Merge pull request #27 from bjdgyc/dtls

添加 DTLS支持

README.md

@@ -60,6 +60,7 @@ sudo ./anylink -conf="conf/server.toml"
 
 - [x] IP分配(实现IP、MAC映射信息的持久化)
 - [x] TLS-TCP通道
+- [x] DTLS-UDP通道
 - [x] 兼容AnyConnect
 - [x] 基于tun设备的nat访问模式
 - [x] 基于tap设备的桥接访问模式
@@ -72,8 +73,6 @@ sudo ./anylink -conf="conf/server.toml"
 - [x] 后台管理界面
 - [x] 访问权限管理
 
-- [ ] DTLS-UDP通道
-
 ## Config
 
 默认配置文件内有详细的注释，根据注释填写配置即可。

dtls-2.0.9/.editorconfig

@@ -0,0 +1,21 @@
+# http://editorconfig.org/
+
+root = true
+
+[*]
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+end_of_line = lf
+
+[*.go]
+indent_style = tab
+indent_size = 4
+
+[{*.yml,*.yaml}]
+indent_style = space
+indent_size = 2
+
+# Makefiles always use tabs for indentation
+[Makefile]
+indent_style = tab

dtls-2.0.9/.github/assert-contributors.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+# If you want to update the shared CI config, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+#
+
+set -e
+
+SCRIPT_PATH=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
+
+if [ -f ${SCRIPT_PATH}/.ci.conf ]
+then
+  . ${SCRIPT_PATH}/.ci.conf
+fi
+
+#
+# DO NOT EDIT THIS
+#
+EXCLUDED_CONTRIBUTORS+=('John R. Bradley' 'renovate[bot]' 'Renovate Bot' 'Pion Bot')
+# If you want to exclude a name from all repositories, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+# If you want to exclude a name only from this repository,
+# add EXCLUDED_CONTRIBUTORS=('name') to .github/.ci.conf
+
+MISSING_CONTRIBUTORS=()
+
+shouldBeIncluded () {
+	for i in "${EXCLUDED_CONTRIBUTORS[@]}"
+	do
+		if [ "$i" == "$1" ] ; then
+			return 1
+		fi
+	done
+	return 0
+}
+
+
+IFS=$'\n' #Only split on newline
+for contributor in $(git log --format='%aN' | sort -u)
+do
+	if shouldBeIncluded $contributor; then
+		if ! grep -q "$contributor" "$SCRIPT_PATH/../README.md"; then
+			MISSING_CONTRIBUTORS+=("$contributor")
+		fi
+	fi
+done
+unset IFS
+
+if [ ${#MISSING_CONTRIBUTORS[@]} -ne 0 ]; then
+    echo "Please add the following contributors to the README"
+    for i in "${MISSING_CONTRIBUTORS[@]}"
+    do
+	    echo "$i"
+    done
+    exit 1
+fi

dtls-2.0.9/.github/hooks/commit-msg.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+#
+# DO NOT EDIT THIS FILE DIRECTLY
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+
+set -e
+
+.github/lint-commit-message.sh $1

dtls-2.0.9/.github/hooks/pre-commit.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+#
+# DO NOT EDIT THIS FILE DIRECTLY
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+
+# Redirect output to stderr.
+exec 1>&2
+
+.github/lint-disallowed-functions-in-library.sh

dtls-2.0.9/.github/hooks/pre-push.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+#
+# DO NOT EDIT THIS FILE DIRECTLY
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+
+set -e
+
+.github/assert-contributors.sh
+
+exit 0

dtls-2.0.9/.github/install-hooks.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+# If you want to update the shared CI config, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+#
+
+SCRIPT_PATH=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
+
+cp "$SCRIPT_PATH/hooks/commit-msg.sh" "$SCRIPT_PATH/../.git/hooks/commit-msg"
+cp "$SCRIPT_PATH/hooks/pre-commit.sh" "$SCRIPT_PATH/../.git/hooks/pre-commit"
+cp "$SCRIPT_PATH/hooks/pre-push.sh" "$SCRIPT_PATH/../.git/hooks/pre-push"

dtls-2.0.9/.github/lint-commit-message.sh

@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+# If you want to update the shared CI config, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+#
+
+set -e
+
+display_commit_message_error() {
+cat << EndOfMessage
+$1
+
+-------------------------------------------------
+The preceding commit message is invalid
+it failed '$2' of the following checks
+
+* Separate subject from body with a blank line
+* Limit the subject line to 50 characters
+* Capitalize the subject line
+* Do not end the subject line with a period
+* Wrap the body at 72 characters
+EndOfMessage
+
+     exit 1
+}
+
+lint_commit_message() {
+    if [[ "$(echo "$1" | awk 'NR == 2 {print $1;}' | wc -c)" -ne 1 ]]; then
+        display_commit_message_error "$1" 'Separate subject from body with a blank line'
+    fi
+
+    if [[ "$(echo "$1" | head -n1 | awk '{print length}')" -gt 50 ]]; then
+        display_commit_message_error "$1" 'Limit the subject line to 50 characters'
+    fi
+
+    if [[ ! $1 =~ ^[A-Z] ]]; then
+        display_commit_message_error "$1" 'Capitalize the subject line'
+    fi
+
+    if [[ "$(echo "$1" | awk 'NR == 1 {print substr($0,length($0),1)}')" == "." ]]; then
+        display_commit_message_error "$1" 'Do not end the subject line with a period'
+    fi
+
+    if [[ "$(echo "$1" | awk '{print length}' | sort -nr | head -1)" -gt 72 ]]; then
+        display_commit_message_error "$1" 'Wrap the body at 72 characters'
+    fi
+}
+
+if [ "$#" -eq 1 ]; then
+   if [ ! -f "$1" ]; then
+       echo "$0 was passed one argument, but was not a valid file"
+       exit 1
+   fi
+   lint_commit_message "$(sed -n '/# Please enter the commit message for your changes. Lines starting/q;p' "$1")"
+else
+    for commit in $(git rev-list --no-merges origin/master..); do
+      lint_commit_message "$(git log --format="%B" -n 1 $commit)"
+    done
+fi

dtls-2.0.9/.github/lint-disallowed-functions-in-library.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+# If you want to update the shared CI config, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+#
+
+set -e
+
+# Disallow usages of functions that cause the program to exit in the library code
+SCRIPT_PATH=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
+if [ -f ${SCRIPT_PATH}/.ci.conf ]
+then
+  . ${SCRIPT_PATH}/.ci.conf
+fi
+
+EXCLUDE_DIRECTORIES=${DISALLOWED_FUNCTIONS_EXCLUDED_DIRECTORIES:-"examples"}
+DISALLOWED_FUNCTIONS=('os.Exit(' 'panic(' 'Fatal(' 'Fatalf(' 'Fatalln(' 'fmt.Println(' 'fmt.Printf(' 'log.Print(' 'log.Println(' 'log.Printf(')
+
+files=$(
+  find "$SCRIPT_PATH/.." -name "*.go" \
+    | grep -v -e '^.*_test.go$' \
+    | while read file
+    do
+      excluded=false
+      for ex in $EXCLUDE_DIRECTORIES
+      do
+        if [[ $file == */$ex/* ]]
+        then
+          excluded=true
+          break
+        fi
+      done
+      $excluded || echo "$file"
+    done
+)
+
+for disallowedFunction in "${DISALLOWED_FUNCTIONS[@]}"
+do
+	if grep -e "$disallowedFunction" $files | grep -v -e 'nolint'; then
+		echo "$disallowedFunction may only be used in example code"
+		exit 1
+	fi
+done

dtls-2.0.9/.github/lint-filename.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+# If you want to update the shared CI config, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+#
+
+set -e
+
+SCRIPT_PATH=$( cd "$(dirname "${BASH_SOURCE[0]}")" ; pwd -P )
+GO_REGEX="^[a-zA-Z][a-zA-Z0-9_]*\.go$"
+
+find  "$SCRIPT_PATH/.." -name "*.go" | while read fullpath; do
+  filename=$(basename -- "$fullpath")
+
+  if ! [[ $filename =~ $GO_REGEX ]]; then
+      echo "$filename is not a valid filename for Go code, only alpha, numbers and underscores are supported"
+      exit 1
+  fi
+done

dtls-2.0.9/.github/workflows/e2e.yaml

@@ -0,0 +1,20 @@
+name: E2E
+on:
+  pull_request:
+    branches:
+      - master
+  push:
+    branches:
+      - master
+
+jobs:
+  e2e-test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v2
+      - name: test
+        run: |
+          docker build -t pion-dtls-e2e -f e2e/Dockerfile .
+          docker run -i --rm pion-dtls-e2e

dtls-2.0.9/.github/workflows/lint.yaml

@@ -0,0 +1,43 @@
+name: Lint
+on:
+  pull_request:
+    types:
+      - opened
+      - edited
+      - synchronize
+jobs:
+  lint-commit-message:
+    name: Metadata
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+        - uses: actions/checkout@v2
+          with:
+            fetch-depth: 0
+
+        - name: Commit Message
+          run: .github/lint-commit-message.sh
+
+        - name: File names
+          run: .github/lint-filename.sh
+
+        - name: Contributors
+          run: .github/assert-contributors.sh
+
+        - name: Functions
+          run: .github/lint-disallowed-functions-in-library.sh
+
+  lint-go:
+    name: Go
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          version: v1.31
+          args: $GOLANGCI_LINT_EXRA_ARGS

dtls-2.0.9/.github/workflows/renovate-go-mod-fix.yaml

@@ -0,0 +1,33 @@
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+# If this repository should have package specific CI config,
+# remove the repository name from .goassets/.github/workflows/assets-sync.yml.
+#
+# If you want to update the shared CI config, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+#
+
+name: go-mod-fix
+on:
+  push:
+    branches:
+      - renovate/*
+
+jobs:
+  go-mod-fix:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 2
+      - name: fix
+        uses: at-wat/go-sum-fix-action@v0
+        with:
+          git_user: Pion Bot
+          git_email: 59523206+pionbot@users.noreply.github.com
+          github_token: ${{ secrets.PIONBOT_PRIVATE_KEY }}
+          commit_style: squash
+          push: force

dtls-2.0.9/.github/workflows/test.yaml

@@ -0,0 +1,139 @@
+name: Test
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go: ["1.15", "1.16"]
+      fail-fast: false
+    name: Go ${{ matrix.go }}
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/go/pkg/mod
+            ~/go/bin
+            ~/.cache
+          key: ${{ runner.os }}-amd64-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-amd64-go-
+
+      - name: Setup Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go }}
+
+      - name: Setup go-acc
+        run: |
+          go get github.com/ory/go-acc
+          git checkout go.mod go.sum
+
+      - name: Run test
+        run: |
+          go-acc -o cover.out ./... -- \
+          -bench=. \
+          -v -race
+
+      - uses: codecov/codecov-action@v1
+        with:
+          file: ./cover.out
+          name: codecov-umbrella
+          fail_ci_if_error: true
+          flags: go
+
+  test-i386:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go: ["1.15", "1.16"]
+      fail-fast: false
+    name: Go i386 ${{ matrix.go }}
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/go/pkg/mod
+            ~/.cache
+          key: ${{ runner.os }}-i386-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-i386-go-
+
+      - name: Run test
+        run: |
+          mkdir -p $HOME/go/pkg/mod $HOME/.cache
+          docker run \
+          -u $(id -u):$(id -g) \
+          -e "GO111MODULE=on" \
+          -e "CGO_ENABLED=0" \
+          -v $GITHUB_WORKSPACE:/go/src/github.com/pion/$(basename $GITHUB_WORKSPACE) \
+          -v $HOME/go/pkg/mod:/go/pkg/mod \
+          -v $HOME/.cache:/.cache \
+          -w /go/src/github.com/pion/$(basename $GITHUB_WORKSPACE) \
+          i386/golang:${{matrix.go}}-alpine \
+          /usr/local/go/bin/go test \
+            ${TEST_EXTRA_ARGS:-} \
+            -v ./...
+
+  test-wasm:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    name: WASM
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Use Node.js
+        uses: actions/setup-node@v2
+        with:
+          node-version: '12.x'
+
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/go/pkg/mod
+            ~/.cache
+          key: ${{ runner.os }}-wasm-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-wasm-go-
+
+      - name: Download Go
+        run: curl -sSfL https://dl.google.com/go/go${GO_VERSION}.linux-amd64.tar.gz | tar -C ~ -xzf -
+        env:
+          GO_VERSION: 1.16
+
+      - name: Set Go Root
+        run: echo "GOROOT=${HOME}/go" >> $GITHUB_ENV
+
+      - name: Set Go Path
+        run: echo "GOPATH=${HOME}/go" >> $GITHUB_ENV
+
+      - name: Set Go Path
+        run: echo "GO_JS_WASM_EXEC=${GOROOT}/misc/wasm/go_js_wasm_exec" >> $GITHUB_ENV
+
+      - name: Insall NPM modules
+        run: yarn install
+
+      - name: Run Tests
+        run: |
+          GOOS=js GOARCH=wasm $GOPATH/bin/go test \
+          -coverprofile=cover.out -covermode=atomic \
+          -exec="${GO_JS_WASM_EXEC}" \
+          -v ./...
+
+      - uses: codecov/codecov-action@v1
+        with:
+          file: ./cover.out
+          name: codecov-umbrella
+          fail_ci_if_error: true
+          flags: wasm

dtls-2.0.9/.github/workflows/tidy-check.yaml

@@ -0,0 +1,37 @@
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+# If this repository should have package specific CI config,
+# remove the repository name from .goassets/.github/workflows/assets-sync.yml.
+#
+# If you want to update the shared CI config, send a PR to
+# https://github.com/pion/.goassets instead of this repository.
+#
+
+name: Go mod tidy
+on:
+  pull_request:
+    branches:
+      - master
+  push:
+    branches:
+      - master
+
+jobs:
+  Check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v2
+      - name: Setup Go
+        uses: actions/setup-go@v2
+      - name: check
+        run: |
+          go mod download
+          go mod tidy
+          if ! git diff --exit-code
+          then
+            echo "Not go mod tidied"
+            exit 1
+          fi

dtls-2.0.9/.gitignore

@@ -0,0 +1,24 @@
+### JetBrains IDE ###
+#####################
+.idea/
+
+### Emacs Temporary Files ###
+#############################
+*~
+
+### Folders ###
+###############
+bin/
+vendor/
+node_modules/
+
+### Files ###
+#############
+*.ivf
+*.ogg
+tags
+cover.out
+*.sw[poe]
+*.wasm
+examples/sfu-ws/cert.pem
+examples/sfu-ws/key.pem

dtls-2.0.9/.golangci.yml

@@ -0,0 +1,89 @@
+linters-settings:
+  govet:
+    check-shadowing: true
+  misspell:
+    locale: US
+  exhaustive:
+    default-signifies-exhaustive: true
+  gomodguard:
+    blocked:
+      modules:
+        - github.com/pkg/errors:
+            recommendations:
+            - errors
+
+linters:
+  enable:
+    - asciicheck       # Simple linter to check that your code does not contain non-ASCII identifiers
+    - bodyclose        # checks whether HTTP response body is closed successfully
+    - deadcode         # Finds unused code
+    - depguard         # Go linter that checks if package imports are in a list of acceptable packages
+    - dogsled          # Checks assignments with too many blank identifiers (e.g. x, _, _, _, := f())
+    - dupl             # Tool for code clone detection
+    - errcheck         # Errcheck is a program for checking for unchecked errors in go programs. These unchecked errors can be critical bugs in some cases
+    - exhaustive       # check exhaustiveness of enum switch statements
+    - exportloopref    # checks for pointers to enclosing loop variables
+    - gci              # Gci control golang package import order and make it always deterministic.
+    - gochecknoglobals # Checks that no globals are present in Go code
+    - gochecknoinits   # Checks that no init functions are present in Go code
+    - gocognit         # Computes and checks the cognitive complexity of functions
+    - goconst          # Finds repeated strings that could be replaced by a constant
+    - gocritic         # The most opinionated Go source code linter
+    - godox            # Tool for detection of FIXME, TODO and other comment keywords
+    - goerr113         # Golang linter to check the errors handling expressions
+    - gofmt            # Gofmt checks whether code was gofmt-ed. By default this tool runs with -s option to check for code simplification
+    - gofumpt          # Gofumpt checks whether code was gofumpt-ed.
+    - goheader         # Checks is file header matches to pattern
+    - goimports        # Goimports does everything that gofmt does. Additionally it checks unused imports
+    - golint           # Golint differs from gofmt. Gofmt reformats Go source code, whereas golint prints out style mistakes
+    - gomodguard       # Allow and block list linter for direct Go module dependencies. This is different from depguard where there are different block types for example version constraints and module recommendations.
+    - goprintffuncname # Checks that printf-like functions are named with `f` at the end
+    - gosec            # Inspects source code for security problems
+    - gosimple         # Linter for Go source code that specializes in simplifying a code
+    - govet            # Vet examines Go source code and reports suspicious constructs, such as Printf calls whose arguments do not align with the format string
+    - ineffassign      # Detects when assignments to existing variables are not used
+    - misspell         # Finds commonly misspelled English words in comments
+    - nakedret         # Finds naked returns in functions greater than a specified function length
+    - noctx            # noctx finds sending http request without context.Context
+    - scopelint        # Scopelint checks for unpinned variables in go programs
+    - staticcheck      # Staticcheck is a go vet on steroids, applying a ton of static analysis checks
+    - structcheck      # Finds unused struct fields
+    - stylecheck       # Stylecheck is a replacement for golint
+    - typecheck        # Like the front-end of a Go compiler, parses and type-checks Go code
+    - unconvert        # Remove unnecessary type conversions
+    - unparam          # Reports unused function parameters
+    - unused           # Checks Go code for unused constants, variables, functions and types
+    - varcheck         # Finds unused global variables and constants
+    - whitespace       # Tool for detection of leading and trailing whitespace
+  disable:
+    - funlen           # Tool for detection of long functions
+    - gocyclo          # Computes and checks the cyclomatic complexity of functions
+    - godot            # Check if comments end in a period
+    - gomnd            # An analyzer to detect magic numbers.
+    - lll              # Reports long lines
+    - maligned         # Tool to detect Go structs that would take less memory if their fields were sorted
+    - nestif           # Reports deeply nested if statements
+    - nlreturn         # nlreturn checks for a new line before return and branch statements to increase code clarity
+    - nolintlint       # Reports ill-formed or insufficient nolint directives
+    - prealloc         # Finds slice declarations that could potentially be preallocated
+    - rowserrcheck     # checks whether Err of rows is checked successfully
+    - sqlclosecheck    # Checks that sql.Rows and sql.Stmt are closed.
+    - testpackage      # linter that makes you use a separate _test package
+    - wsl              # Whitespace Linter - Forces you to use empty lines!
+
+issues:
+  exclude-use-default: false
+  exclude-rules:
+    # Allow complex tests, better to be self contained
+    - path: _test\.go
+      linters:
+        - gocognit
+
+    # Allow complex main function in examples
+    - path: examples
+      text: "of func `main` is high"
+      linters:
+        - gocognit
+
+run:
+  skip-dirs-use-default: false

dtls-2.0.9/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

dtls-2.0.9/Makefile

@@ -0,0 +1,6 @@
+fuzz-build-record-layer: fuzz-prepare
+	go-fuzz-build -tags gofuzz -func FuzzRecordLayer
+fuzz-run-record-layer:
+	go-fuzz -bin dtls-fuzz.zip -workdir fuzz
+fuzz-prepare:
+	@GO111MODULE=on go mod vendor

dtls-2.0.9/README.md

@@ -0,0 +1,156 @@
+<h1 align="center">
+  <br>
+  Pion DTLS
+  <br>
+</h1>
+<h4 align="center">A Go implementation of DTLS</h4>
+<p align="center">
+  <a href="https://pion.ly"><img src="https://img.shields.io/badge/pion-dtls-gray.svg?longCache=true&colorB=brightgreen" alt="Pion DTLS"></a>
+  <a href="https://sourcegraph.com/github.com/pion/dtls"><img src="https://sourcegraph.com/github.com/pion/dtls/-/badge.svg" alt="Sourcegraph Widget"></a>
+  <a href="https://pion.ly/slack"><img src="https://img.shields.io/badge/join-us%20on%20slack-gray.svg?longCache=true&logo=slack&colorB=brightgreen" alt="Slack Widget"></a>
+  <br>
+  <a href="https://travis-ci.org/pion/dtls"><img src="https://travis-ci.org/pion/dtls.svg?branch=master" alt="Build Status"></a>
+  <a href="https://pkg.go.dev/github.com/pion/dtls"><img src="https://godoc.org/github.com/pion/dtls?status.svg" alt="GoDoc"></a>
+  <a href="https://codecov.io/gh/pion/dtls"><img src="https://codecov.io/gh/pion/dtls/branch/master/graph/badge.svg" alt="Coverage Status"></a>
+  <a href="https://goreportcard.com/report/github.com/pion/dtls"><img src="https://goreportcard.com/badge/github.com/pion/dtls" alt="Go Report Card"></a>
+  <a href="https://www.codacy.com/app/Sean-Der/dtls"><img src="https://api.codacy.com/project/badge/Grade/18f4aec384894e6aac0b94effe51961d" alt="Codacy Badge"></a>
+  <a href="LICENSE"><img src="https://img.shields.io/badge/License-MIT-yellow.svg" alt="License: MIT"></a>
+</p>
+<br>
+
+Native [DTLS 1.2][rfc6347] implementation in the Go programming language.
+
+A long term goal is a professional security review, and maye inclusion in stdlib.
+
+[rfc6347]: https://tools.ietf.org/html/rfc6347
+
+### Goals/Progress
+This will only be targeting DTLS 1.2, and the most modern/common cipher suites.
+We would love contributes that fall under the 'Planned Features' and fixing any bugs!
+
+#### Current features
+* DTLS 1.2 Client/Server
+* Key Exchange via ECDHE(curve25519, nistp256, nistp384) and PSK
+* Packet loss and re-ordering is handled during handshaking
+* Key export ([RFC 5705][rfc5705])
+* Serialization and Resumption of sessions
+* Extended Master Secret extension ([RFC 7627][rfc7627])
+
+[rfc5705]: https://tools.ietf.org/html/rfc5705
+[rfc7627]: https://tools.ietf.org/html/rfc7627
+
+#### Supported ciphers
+
+##### ECDHE
+* TLS_ECDHE_ECDSA_WITH_AES_128_CCM ([RFC 6655][rfc6655])
+* TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 ([RFC 6655][rfc6655])
+* TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 ([RFC 5289][rfc5289])
+* TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 ([RFC 5289][rfc5289])
+* TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA ([RFC 8422][rfc8422])
+* TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA ([RFC 8422][rfc8422])
+
+##### PSK
+* TLS_PSK_WITH_AES_128_CCM ([RFC 6655][rfc6655])
+* TLS_PSK_WITH_AES_128_CCM_8 ([RFC 6655][rfc6655])
+* TLS_PSK_WITH_AES_128_GCM_SHA256 ([RFC 5487][rfc5487])
+* TLS_PSK_WITH_AES_128_CBC_SHA256 ([RFC 5487][rfc5487])
+
+[rfc5289]: https://tools.ietf.org/html/rfc5289
+[rfc8422]: https://tools.ietf.org/html/rfc8422
+[rfc6655]: https://tools.ietf.org/html/rfc6655
+[rfc5487]: https://tools.ietf.org/html/rfc5487
+
+#### Planned Features
+* Chacha20Poly1305
+
+#### Excluded Features
+* DTLS 1.0
+* Renegotiation
+* Compression
+
+### Using
+
+This library needs at least Go 1.13, and you should have [Go modules
+enabled](https://github.com/golang/go/wiki/Modules).
+
+#### Pion DTLS
+For a DTLS 1.2 Server that listens on 127.0.0.1:4444
+```sh
+go run examples/listen/selfsign/main.go
+```
+
+For a DTLS 1.2 Client that connects to 127.0.0.1:4444
+```sh
+go run examples/dial/selfsign/main.go
+```
+
+#### OpenSSL
+Pion DTLS can connect to itself and OpenSSL.
+```
+  // Generate a certificate
+  openssl ecparam -out key.pem -name prime256v1 -genkey
+  openssl req -new -sha256 -key key.pem -out server.csr
+  openssl x509 -req -sha256 -days 365 -in server.csr -signkey key.pem -out cert.pem
+
+  // Use with examples/dial/selfsign/main.go
+  openssl s_server -dtls1_2 -cert cert.pem -key key.pem -accept 4444
+
+  // Use with examples/listen/selfsign/main.go
+  openssl s_client -dtls1_2 -connect 127.0.0.1:4444 -debug -cert cert.pem -key key.pem
+```
+
+### Using with PSK
+Pion DTLS also comes with examples that do key exchange via PSK
+
+
+#### Pion DTLS
+```sh
+go run examples/listen/psk/main.go
+```
+
+```sh
+go run examples/dial/psk/main.go
+```
+
+#### OpenSSL
+```
+  // Use with examples/dial/psk/main.go
+  openssl s_server -dtls1_2 -accept 4444 -nocert -psk abc123 -cipher PSK-AES128-CCM8
+
+  // Use with examples/listen/psk/main.go
+  openssl s_client -dtls1_2 -connect 127.0.0.1:4444 -psk abc123 -cipher PSK-AES128-CCM8
+```
+
+### Contributing
+Check out the **[contributing wiki](https://github.com/pion/webrtc/wiki/Contributing)** to join the group of amazing people making this project possible:
+
+* [Sean DuBois](https://github.com/Sean-Der) - *Original Author*
+* [Michiel De Backker](https://github.com/backkem) - *Public API*
+* [Chris Hiszpanski](https://github.com/thinkski) - *Support Signature Algorithms Extension*
+* [Iñigo Garcia Olaizola](https://github.com/igolaizola) - *Serialization & resumption, cert verification, E2E*
+* [Daniele Sluijters](https://github.com/daenney) - *AES-CCM support*
+* [Jin Lei](https://github.com/jinleileiking) - *Logging*
+* [Hugo Arregui](https://github.com/hugoArregui)
+* [Lander Noterman](https://github.com/LanderN)
+* [Aleksandr Razumov](https://github.com/ernado) - *Fuzzing*
+* [Ryan Gordon](https://github.com/ryangordon)
+* [Stefan Tatschner](https://rumpelsepp.org/contact.html)
+* [Hayden James](https://github.com/hjames9)
+* [Jozef Kralik](https://github.com/jkralik)
+* [Robert Eperjesi](https://github.com/epes)
+* [Atsushi Watanabe](https://github.com/at-wat)
+* [Julien Salleyron](https://github.com/juliens) - *Server Name Indication*
+* [Jeroen de Bruijn](https://github.com/vidavidorra)
+* [bjdgyc](https://github.com/bjdgyc)
+* [Jeffrey Stoke (Jeff Ctor)](https://github.com/jeffreystoke) - *Fragmentbuffer Fix*
+* [Frank Olbricht](https://github.com/folbricht)
+* [ZHENK](https://github.com/scorpionknifes)
+* [Carson Hoffman](https://github.com/CarsonHoffman)
+* [Vadim Filimonov](https://github.com/fffilimonov)
+* [Jim Wert](https://github.com/bocajim)
+* [Alvaro Viebrantz](https://github.com/alvarowolfx)
+* [Kegan Dougal](https://github.com/Kegsay)
+* [Michael Zabka](https://github.com/misak113)
+
+### License
+MIT License - see [LICENSE](LICENSE) for full text

dtls-2.0.9/bench_test.go

@@ -0,0 +1,118 @@
+package dtls
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2/internal/net/dpipe"
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+	"github.com/pion/logging"
+	"github.com/pion/transport/test"
+)
+
+func TestSimpleReadWrite(t *testing.T) {
+	report := test.CheckRoutines(t)
+	defer report()
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	ca, cb := dpipe.Pipe()
+	certificate, err := selfsign.GenerateSelfSigned()
+	if err != nil {
+		t.Fatal(err)
+	}
+	gotHello := make(chan struct{})
+
+	go func() {
+		server, sErr := testServer(ctx, cb, &Config{
+			Certificates:  []tls.Certificate{certificate},
+			LoggerFactory: logging.NewDefaultLoggerFactory(),
+		}, false)
+		if sErr != nil {
+			t.Error(sErr)
+			return
+		}
+		buf := make([]byte, 1024)
+		if _, sErr = server.Read(buf); sErr != nil {
+			t.Error(sErr)
+		}
+		gotHello <- struct{}{}
+		if sErr = server.Close(); sErr != nil {
+			t.Error(sErr)
+		}
+	}()
+
+	client, err := testClient(ctx, ca, &Config{
+		LoggerFactory:      logging.NewDefaultLoggerFactory(),
+		InsecureSkipVerify: true,
+	}, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err = client.Write([]byte("hello")); err != nil {
+		t.Error(err)
+	}
+	select {
+	case <-gotHello:
+		// OK
+	case <-time.After(time.Second * 5):
+		t.Error("timeout")
+	}
+
+	if err = client.Close(); err != nil {
+		t.Error(err)
+	}
+}
+
+func benchmarkConn(b *testing.B, n int64) {
+	b.Run(fmt.Sprintf("%d", n), func(b *testing.B) {
+		ctx := context.Background()
+
+		ca, cb := dpipe.Pipe()
+		certificate, err := selfsign.GenerateSelfSigned()
+		server := make(chan *Conn)
+		go func() {
+			s, sErr := testServer(ctx, cb, &Config{
+				Certificates: []tls.Certificate{certificate},
+			}, false)
+			if err != nil {
+				b.Error(sErr)
+				return
+			}
+			server <- s
+		}()
+		if err != nil {
+			b.Fatal(err)
+		}
+		hw := make([]byte, n)
+		b.ReportAllocs()
+		b.SetBytes(int64(len(hw)))
+		go func() {
+			client, cErr := testClient(ctx, ca, &Config{InsecureSkipVerify: true}, false)
+			if cErr != nil {
+				b.Error(err)
+			}
+			for {
+				if _, cErr = client.Write(hw); cErr != nil {
+					b.Error(err)
+				}
+			}
+		}()
+		s := <-server
+		buf := make([]byte, 2048)
+		for i := 0; i < b.N; i++ {
+			if _, err = s.Read(buf); err != nil {
+				b.Error(err)
+			}
+		}
+	})
+}
+
+func BenchmarkConnReadWrite(b *testing.B) {
+	for _, n := range []int64{16, 128, 512, 1024, 2048} {
+		benchmarkConn(b, n)
+	}
+}

dtls-2.0.9/certificate.go

@@ -0,0 +1,67 @@
+package dtls
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"strings"
+)
+
+func (c *handshakeConfig) getCertificate(serverName string) (*tls.Certificate, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if c.nameToCertificate == nil {
+		nameToCertificate := make(map[string]*tls.Certificate)
+		for i := range c.localCertificates {
+			cert := &c.localCertificates[i]
+			x509Cert := cert.Leaf
+			if x509Cert == nil {
+				var parseErr error
+				x509Cert, parseErr = x509.ParseCertificate(cert.Certificate[0])
+				if parseErr != nil {
+					continue
+				}
+			}
+			if len(x509Cert.Subject.CommonName) > 0 {
+				nameToCertificate[strings.ToLower(x509Cert.Subject.CommonName)] = cert
+			}
+			for _, san := range x509Cert.DNSNames {
+				nameToCertificate[strings.ToLower(san)] = cert
+			}
+		}
+		c.nameToCertificate = nameToCertificate
+	}
+
+	if len(c.localCertificates) == 0 {
+		return nil, errNoCertificates
+	}
+
+	if len(c.localCertificates) == 1 {
+		// There's only one choice, so no point doing any work.
+		return &c.localCertificates[0], nil
+	}
+
+	if len(serverName) == 0 {
+		return &c.localCertificates[0], nil
+	}
+
+	name := strings.TrimRight(strings.ToLower(serverName), ".")
+
+	if cert, ok := c.nameToCertificate[name]; ok {
+		return cert, nil
+	}
+
+	// try replacing labels in the name with wildcards until we get a
+	// match.
+	labels := strings.Split(name, ".")
+	for i := range labels {
+		labels[i] = "*"
+		candidate := strings.Join(labels, ".")
+		if cert, ok := c.nameToCertificate[candidate]; ok {
+			return cert, nil
+		}
+	}
+
+	// If nothing matches, return the first certificate.
+	return &c.localCertificates[0], nil
+}

dtls-2.0.9/certificate_test.go

@@ -0,0 +1,79 @@
+package dtls
+
+import (
+	"crypto/tls"
+	"reflect"
+	"testing"
+
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+)
+
+func TestGetCertificate(t *testing.T) {
+	certificateWildcard, err := selfsign.GenerateSelfSignedWithDNS("*.test.test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	certificateTest, err := selfsign.GenerateSelfSignedWithDNS("test.test", "www.test.test", "pop.test.test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	certificateRandom, err := selfsign.GenerateSelfSigned()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cfg := &handshakeConfig{
+		localCertificates: []tls.Certificate{
+			certificateRandom,
+			certificateTest,
+			certificateWildcard,
+		},
+	}
+
+	testCases := []struct {
+		desc                string
+		serverName          string
+		expectedCertificate tls.Certificate
+	}{
+		{
+			desc:                "Simple match in CN",
+			serverName:          "test.test",
+			expectedCertificate: certificateTest,
+		},
+		{
+			desc:                "Simple match in SANs",
+			serverName:          "www.test.test",
+			expectedCertificate: certificateTest,
+		},
+
+		{
+			desc:                "Wildcard match",
+			serverName:          "foo.test.test",
+			expectedCertificate: certificateWildcard,
+		},
+		{
+			desc:                "No match return first",
+			serverName:          "foo.bar",
+			expectedCertificate: certificateRandom,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			cert, err := cfg.getCertificate(test.serverName)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if !reflect.DeepEqual(cert.Leaf, test.expectedCertificate.Leaf) {
+				t.Fatalf("Certificate does not match: expected(%v) actual(%v)", test.expectedCertificate.Leaf, cert.Leaf)
+			}
+		})
+	}
+}

dtls-2.0.9/cipher_suite.go

@@ -0,0 +1,213 @@
+package dtls
+
+import (
+	"fmt"
+	"hash"
+
+	"github.com/pion/dtls/v2/internal/ciphersuite"
+	"github.com/pion/dtls/v2/pkg/crypto/clientcertificate"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+// CipherSuiteID is an ID for our supported CipherSuites
+type CipherSuiteID = ciphersuite.ID
+
+// Supported Cipher Suites
+const (
+	// AES-128-CCM
+	TLS_ECDHE_ECDSA_WITH_AES_128_CCM   CipherSuiteID = ciphersuite.TLS_ECDHE_ECDSA_WITH_AES_128_CCM   //nolint:golint,stylecheck
+	TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 CipherSuiteID = ciphersuite.TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 //nolint:golint,stylecheck
+
+	// AES-128-GCM-SHA256
+	TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 CipherSuiteID = ciphersuite.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 //nolint:golint,stylecheck
+	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256   CipherSuiteID = ciphersuite.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256   //nolint:golint,stylecheck
+
+	// AES-256-CBC-SHA
+	TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA CipherSuiteID = ciphersuite.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA //nolint:golint,stylecheck
+	TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA   CipherSuiteID = ciphersuite.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA   //nolint:golint,stylecheck
+
+	TLS_PSK_WITH_AES_128_CCM        CipherSuiteID = ciphersuite.TLS_PSK_WITH_AES_128_CCM        //nolint:golint,stylecheck
+	TLS_PSK_WITH_AES_128_CCM_8      CipherSuiteID = ciphersuite.TLS_PSK_WITH_AES_128_CCM_8      //nolint:golint,stylecheck
+	TLS_PSK_WITH_AES_128_GCM_SHA256 CipherSuiteID = ciphersuite.TLS_PSK_WITH_AES_128_GCM_SHA256 //nolint:golint,stylecheck
+	TLS_PSK_WITH_AES_128_CBC_SHA256 CipherSuiteID = ciphersuite.TLS_PSK_WITH_AES_128_CBC_SHA256 //nolint:golint,stylecheck
+)
+
+// CipherSuiteAuthenticationType controls what authentication method is using during the handshake for a CipherSuite
+type CipherSuiteAuthenticationType = ciphersuite.AuthenticationType
+
+// AuthenticationType Enums
+const (
+	CipherSuiteAuthenticationTypeCertificate  CipherSuiteAuthenticationType = ciphersuite.AuthenticationTypeCertificate
+	CipherSuiteAuthenticationTypePreSharedKey CipherSuiteAuthenticationType = ciphersuite.AuthenticationTypePreSharedKey
+	CipherSuiteAuthenticationTypeAnonymous    CipherSuiteAuthenticationType = ciphersuite.AuthenticationTypeAnonymous
+)
+
+var _ = allCipherSuites() // Necessary until this function isn't only used by Go 1.14
+
+// CipherSuite is an interface that all DTLS CipherSuites must satisfy
+type CipherSuite interface {
+	// String of CipherSuite, only used for logging
+	String() string
+
+	// ID of CipherSuite.
+	ID() CipherSuiteID
+
+	// What type of Certificate does this CipherSuite use
+	CertificateType() clientcertificate.Type
+
+	// What Hash function is used during verification
+	HashFunc() func() hash.Hash
+
+	// AuthenticationType controls what authentication method is using during the handshake
+	AuthenticationType() CipherSuiteAuthenticationType
+
+	// Called when keying material has been generated, should initialize the internal cipher
+	Init(masterSecret, clientRandom, serverRandom []byte, isClient bool) error
+	IsInitialized() bool
+
+	Encrypt(pkt *recordlayer.RecordLayer, raw []byte) ([]byte, error)
+	Decrypt(in []byte) ([]byte, error)
+}
+
+// CipherSuiteName provides the same functionality as tls.CipherSuiteName
+// that appeared first in Go 1.14.
+//
+// Our implementation differs slightly in that it takes in a CiperSuiteID,
+// like the rest of our library, instead of a uint16 like crypto/tls.
+func CipherSuiteName(id CipherSuiteID) string {
+	suite := cipherSuiteForID(id, nil)
+	if suite != nil {
+		return suite.String()
+	}
+	return fmt.Sprintf("0x%04X", uint16(id))
+}
+
+// Taken from https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
+// A cipherSuite is a specific combination of key agreement, cipher and MAC
+// function.
+func cipherSuiteForID(id CipherSuiteID, customCiphers func() []CipherSuite) CipherSuite {
+	switch id { //nolint:exhaustive
+	case TLS_ECDHE_ECDSA_WITH_AES_128_CCM:
+		return ciphersuite.NewTLSEcdheEcdsaWithAes128Ccm()
+	case TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8:
+		return ciphersuite.NewTLSEcdheEcdsaWithAes128Ccm8()
+	case TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:
+		return &ciphersuite.TLSEcdheEcdsaWithAes128GcmSha256{}
+	case TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256:
+		return &ciphersuite.TLSEcdheRsaWithAes128GcmSha256{}
+	case TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA:
+		return &ciphersuite.TLSEcdheEcdsaWithAes256CbcSha{}
+	case TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA:
+		return &ciphersuite.TLSEcdheRsaWithAes256CbcSha{}
+	case TLS_PSK_WITH_AES_128_CCM:
+		return ciphersuite.NewTLSPskWithAes128Ccm()
+	case TLS_PSK_WITH_AES_128_CCM_8:
+		return ciphersuite.NewTLSPskWithAes128Ccm8()
+	case TLS_PSK_WITH_AES_128_GCM_SHA256:
+		return &ciphersuite.TLSPskWithAes128GcmSha256{}
+	case TLS_PSK_WITH_AES_128_CBC_SHA256:
+		return &ciphersuite.TLSPskWithAes128CbcSha256{}
+	}
+
+	if customCiphers != nil {
+		for _, c := range customCiphers() {
+			if c.ID() == id {
+				return c
+			}
+		}
+	}
+
+	return nil
+}
+
+// CipherSuites we support in order of preference
+func defaultCipherSuites() []CipherSuite {
+	return []CipherSuite{
+		&ciphersuite.TLSEcdheEcdsaWithAes128GcmSha256{},
+		&ciphersuite.TLSEcdheRsaWithAes128GcmSha256{},
+		&ciphersuite.TLSEcdheEcdsaWithAes256CbcSha{},
+		&ciphersuite.TLSEcdheRsaWithAes256CbcSha{},
+	}
+}
+
+func allCipherSuites() []CipherSuite {
+	return []CipherSuite{
+		ciphersuite.NewTLSEcdheEcdsaWithAes128Ccm(),
+		ciphersuite.NewTLSEcdheEcdsaWithAes128Ccm8(),
+		&ciphersuite.TLSEcdheEcdsaWithAes128GcmSha256{},
+		&ciphersuite.TLSEcdheRsaWithAes128GcmSha256{},
+		&ciphersuite.TLSEcdheEcdsaWithAes256CbcSha{},
+		&ciphersuite.TLSEcdheRsaWithAes256CbcSha{},
+		ciphersuite.NewTLSPskWithAes128Ccm(),
+		ciphersuite.NewTLSPskWithAes128Ccm8(),
+		&ciphersuite.TLSPskWithAes128GcmSha256{},
+	}
+}
+
+func cipherSuiteIDs(cipherSuites []CipherSuite) []uint16 {
+	rtrn := []uint16{}
+	for _, c := range cipherSuites {
+		rtrn = append(rtrn, uint16(c.ID()))
+	}
+	return rtrn
+}
+
+func parseCipherSuites(userSelectedSuites []CipherSuiteID, customCipherSuites func() []CipherSuite, includeCertificateSuites, includePSKSuites bool) ([]CipherSuite, error) {
+	cipherSuitesForIDs := func(ids []CipherSuiteID) ([]CipherSuite, error) {
+		cipherSuites := []CipherSuite{}
+		for _, id := range ids {
+			c := cipherSuiteForID(id, nil)
+			if c == nil {
+				return nil, &invalidCipherSuite{id}
+			}
+			cipherSuites = append(cipherSuites, c)
+		}
+		return cipherSuites, nil
+	}
+
+	var (
+		cipherSuites []CipherSuite
+		err          error
+		i            int
+	)
+	if userSelectedSuites != nil {
+		cipherSuites, err = cipherSuitesForIDs(userSelectedSuites)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		cipherSuites = defaultCipherSuites()
+	}
+
+	// Put CustomCipherSuites before ID selected suites
+	if customCipherSuites != nil {
+		cipherSuites = append(customCipherSuites(), cipherSuites...)
+	}
+
+	var foundCertificateSuite, foundPSKSuite, foundAnonymousSuite bool
+	for _, c := range cipherSuites {
+		switch {
+		case includeCertificateSuites && c.AuthenticationType() == CipherSuiteAuthenticationTypeCertificate:
+			foundCertificateSuite = true
+		case includePSKSuites && c.AuthenticationType() == CipherSuiteAuthenticationTypePreSharedKey:
+			foundPSKSuite = true
+		case c.AuthenticationType() == CipherSuiteAuthenticationTypeAnonymous:
+			foundAnonymousSuite = true
+		default:
+			continue
+		}
+		cipherSuites[i] = c
+		i++
+	}
+
+	switch {
+	case includeCertificateSuites && !foundCertificateSuite && !foundAnonymousSuite:
+		return nil, errNoAvailableCertificateCipherSuite
+	case includePSKSuites && !foundPSKSuite:
+		return nil, errNoAvailablePSKCipherSuite
+	case i == 0:
+		return nil, errNoAvailableCipherSuites
+	}
+
+	return cipherSuites[:i], nil
+}

dtls-2.0.9/cipher_suite_go114.go

@@ -0,0 +1,40 @@
+// +build go1.14
+
+package dtls
+
+import (
+	"crypto/tls"
+)
+
+// VersionDTLS12 is the DTLS version in the same style as
+// VersionTLSXX from crypto/tls
+const VersionDTLS12 = 0xfefd
+
+// Convert from our cipherSuite interface to a tls.CipherSuite struct
+func toTLSCipherSuite(c CipherSuite) *tls.CipherSuite {
+	return &tls.CipherSuite{
+		ID:                uint16(c.ID()),
+		Name:              c.String(),
+		SupportedVersions: []uint16{VersionDTLS12},
+		Insecure:          false,
+	}
+}
+
+// CipherSuites returns a list of cipher suites currently implemented by this
+// package, excluding those with security issues, which are returned by
+// InsecureCipherSuites.
+func CipherSuites() []*tls.CipherSuite {
+	suites := allCipherSuites()
+	res := make([]*tls.CipherSuite, len(suites))
+	for i, c := range suites {
+		res[i] = toTLSCipherSuite(c)
+	}
+	return res
+}
+
+// InsecureCipherSuites returns a list of cipher suites currently implemented by
+// this package and which have security issues.
+func InsecureCipherSuites() []*tls.CipherSuite {
+	var res []*tls.CipherSuite
+	return res
+}

dtls-2.0.9/cipher_suite_go114_test.go

@@ -0,0 +1,51 @@
+// +build go1.14
+
+package dtls
+
+import (
+	"testing"
+)
+
+func TestInsecureCipherSuites(t *testing.T) {
+	r := InsecureCipherSuites()
+
+	if len(r) != 0 {
+		t.Fatalf("Expected no insecure ciphersuites, got %d", len(r))
+	}
+}
+
+func TestCipherSuites(t *testing.T) {
+	ours := allCipherSuites()
+	theirs := CipherSuites()
+
+	if len(ours) != len(theirs) {
+		t.Fatalf("Expected %d CipherSuites, got %d", len(ours), len(theirs))
+	}
+
+	for i, s := range ours {
+		i := i
+		s := s
+		t.Run(s.String(), func(t *testing.T) {
+			c := theirs[i]
+			if c.ID != uint16(s.ID()) {
+				t.Fatalf("Expected ID: 0x%04X, got 0x%04X", s.ID(), c.ID)
+			}
+
+			if c.Name != s.String() {
+				t.Fatalf("Expected Name: %s, got %s", s.String(), c.Name)
+			}
+
+			if len(c.SupportedVersions) != 1 {
+				t.Fatalf("Expected %d SupportedVersion, got %d", 1, len(c.SupportedVersions))
+			}
+
+			if c.SupportedVersions[0] != VersionDTLS12 {
+				t.Fatalf("Expected SupportedVersions 0x%04X, got 0x%04X", VersionDTLS12, c.SupportedVersions[0])
+			}
+
+			if c.Insecure {
+				t.Fatalf("Expected Insecure %t, got %t", false, c.Insecure)
+			}
+		})
+	}
+}

dtls-2.0.9/cipher_suite_test.go

@@ -0,0 +1,108 @@
+package dtls
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2/internal/ciphersuite"
+	"github.com/pion/dtls/v2/internal/net/dpipe"
+	"github.com/pion/transport/test"
+)
+
+func TestCipherSuiteName(t *testing.T) {
+	testCases := []struct {
+		suite    CipherSuiteID
+		expected string
+	}{
+		{TLS_ECDHE_ECDSA_WITH_AES_128_CCM, "TLS_ECDHE_ECDSA_WITH_AES_128_CCM"},
+		{CipherSuiteID(0x0000), "0x0000"},
+	}
+
+	for _, testCase := range testCases {
+		res := CipherSuiteName(testCase.suite)
+		if res != testCase.expected {
+			t.Fatalf("Expected: %s, got %s", testCase.expected, res)
+		}
+	}
+}
+
+func TestAllCipherSuites(t *testing.T) {
+	actual := len(allCipherSuites())
+	if actual == 0 {
+		t.Fatal()
+	}
+}
+
+// CustomCipher that is just used to assert Custom IDs work
+type testCustomCipherSuite struct {
+	ciphersuite.TLSEcdheEcdsaWithAes128GcmSha256
+	authenticationType CipherSuiteAuthenticationType
+}
+
+func (t *testCustomCipherSuite) ID() CipherSuiteID {
+	return 0xFFFF
+}
+
+func (t *testCustomCipherSuite) AuthenticationType() CipherSuiteAuthenticationType {
+	return t.authenticationType
+}
+
+// Assert that two connections that pass in a CipherSuite with a CustomID works
+func TestCustomCipherSuite(t *testing.T) {
+	type result struct {
+		c   *Conn
+		err error
+	}
+
+	// Check for leaking routines
+	report := test.CheckRoutines(t)
+	defer report()
+
+	runTest := func(cipherFactory func() []CipherSuite) {
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+
+		ca, cb := dpipe.Pipe()
+		c := make(chan result)
+
+		go func() {
+			client, err := testClient(ctx, ca, &Config{
+				CipherSuites:       []CipherSuiteID{},
+				CustomCipherSuites: cipherFactory,
+			}, true)
+			c <- result{client, err}
+		}()
+
+		server, err := testServer(ctx, cb, &Config{
+			CipherSuites:       []CipherSuiteID{},
+			CustomCipherSuites: cipherFactory,
+		}, true)
+
+		clientResult := <-c
+
+		if err != nil {
+			t.Error(err)
+		} else {
+			_ = server.Close()
+		}
+
+		if clientResult.err != nil {
+			t.Error(clientResult.err)
+		} else {
+			_ = clientResult.c.Close()
+		}
+	}
+
+	t.Run("Custom ID", func(t *testing.T) {
+		runTest(func() []CipherSuite {
+			return []CipherSuite{&testCustomCipherSuite{authenticationType: CipherSuiteAuthenticationTypeCertificate}}
+		})
+	})
+
+	t.Run("Anonymous Cipher", func(t *testing.T) {
+		runTest(func() []CipherSuite {
+			return []CipherSuite{&testCustomCipherSuite{authenticationType: CipherSuiteAuthenticationTypeAnonymous}}
+		})
+	})
+}

dtls-2.0.9/codecov.yml

@@ -0,0 +1,20 @@
+#
+# DO NOT EDIT THIS FILE
+#
+# It is automatically copied from https://github.com/pion/.goassets repository.
+#
+
+coverage:
+  status:
+    project:
+      default:
+        # Allow decreasing 2% of total coverage to avoid noise.
+        threshold: 2%
+    patch:
+      default:
+        target: 70%
+        only_pulls: true
+
+ignore:
+  - "examples/*"
+  - "examples/**/*"

dtls-2.0.9/compression_method.go

@@ -0,0 +1,9 @@
+package dtls
+
+import "github.com/pion/dtls/v2/pkg/protocol"
+
+func defaultCompressionMethods() []*protocol.CompressionMethod {
+	return []*protocol.CompressionMethod{
+		{},
+	}
+}

dtls-2.0.9/config.go

@@ -0,0 +1,197 @@
+package dtls
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"io"
+	"time"
+
+	"github.com/pion/logging"
+)
+
+const keyLogLabelTLS12 = "CLIENT_RANDOM"
+
+// Config is used to configure a DTLS client or server.
+// After a Config is passed to a DTLS function it must not be modified.
+type Config struct {
+	// Certificates contains certificate chain to present to the other side of the connection.
+	// Server MUST set this if PSK is non-nil
+	// client SHOULD sets this so CertificateRequests can be handled if PSK is non-nil
+	Certificates []tls.Certificate
+
+	// CipherSuites is a list of supported cipher suites.
+	// If CipherSuites is nil, a default list is used
+	CipherSuites []CipherSuiteID
+
+	// CustomCipherSuites is a list of CipherSuites that can be
+	// provided by the user. This allow users to user Ciphers that are reserved
+	// for private usage.
+	CustomCipherSuites func() []CipherSuite
+
+	// SignatureSchemes contains the signature and hash schemes that the peer requests to verify.
+	SignatureSchemes []tls.SignatureScheme
+
+	// SRTPProtectionProfiles are the supported protection profiles
+	// Clients will send this via use_srtp and assert that the server properly responds
+	// Servers will assert that clients send one of these profiles and will respond as needed
+	SRTPProtectionProfiles []SRTPProtectionProfile
+
+	// ClientAuth determines the server's policy for
+	// TLS Client Authentication. The default is NoClientCert.
+	ClientAuth ClientAuthType
+
+	// RequireExtendedMasterSecret determines if the "Extended Master Secret" extension
+	// should be disabled, requested, or required (default requested).
+	ExtendedMasterSecret ExtendedMasterSecretType
+
+	// FlightInterval controls how often we send outbound handshake messages
+	// defaults to time.Second
+	FlightInterval time.Duration
+
+	// PSK sets the pre-shared key used by this DTLS connection
+	// If PSK is non-nil only PSK CipherSuites will be used
+	PSK             PSKCallback
+	PSKIdentityHint []byte
+
+	CiscoCompat PSKCallback // TODO add cisco anyconnect support
+
+	// InsecureSkipVerify controls whether a client verifies the
+	// server's certificate chain and host name.
+	// If InsecureSkipVerify is true, TLS accepts any certificate
+	// presented by the server and any host name in that certificate.
+	// In this mode, TLS is susceptible to man-in-the-middle attacks.
+	// This should be used only for testing.
+	InsecureSkipVerify bool
+
+	// InsecureHashes allows the use of hashing algorithms that are known
+	// to be vulnerable.
+	InsecureHashes bool
+
+	// VerifyPeerCertificate, if not nil, is called after normal
+	// certificate verification by either a client or server. It
+	// receives the certificate provided by the peer and also a flag
+	// that tells if normal verification has succeedded. If it returns a
+	// non-nil error, the handshake is aborted and that error results.
+	//
+	// If normal verification fails then the handshake will abort before
+	// considering this callback. If normal verification is disabled by
+	// setting InsecureSkipVerify, or (for a server) when ClientAuth is
+	// RequestClientCert or RequireAnyClientCert, then this callback will
+	// be considered but the verifiedChains will always be nil.
+	VerifyPeerCertificate func(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error
+
+	// RootCAs defines the set of root certificate authorities
+	// that one peer uses when verifying the other peer's certificates.
+	// If RootCAs is nil, TLS uses the host's root CA set.
+	RootCAs *x509.CertPool
+
+	// ClientCAs defines the set of root certificate authorities
+	// that servers use if required to verify a client certificate
+	// by the policy in ClientAuth.
+	ClientCAs *x509.CertPool
+
+	// ServerName is used to verify the hostname on the returned
+	// certificates unless InsecureSkipVerify is given.
+	ServerName string
+
+	LoggerFactory logging.LoggerFactory
+
+	// ConnectContextMaker is a function to make a context used in Dial(),
+	// Client(), Server(), and Accept(). If nil, the default ConnectContextMaker
+	// is used. It can be implemented as following.
+	//
+	// 	func ConnectContextMaker() (context.Context, func()) {
+	// 		return context.WithTimeout(context.Background(), 30*time.Second)
+	// 	}
+	ConnectContextMaker func() (context.Context, func())
+
+	// MTU is the length at which handshake messages will be fragmented to
+	// fit within the maximum transmission unit (default is 1200 bytes)
+	MTU int
+
+	// ReplayProtectionWindow is the size of the replay attack protection window.
+	// Duplication of the sequence number is checked in this window size.
+	// Packet with sequence number older than this value compared to the latest
+	// accepted packet will be discarded. (default is 64)
+	ReplayProtectionWindow int
+
+	// KeyLogWriter optionally specifies a destination for TLS master secrets
+	// in NSS key log format that can be used to allow external programs
+	// such as Wireshark to decrypt TLS connections.
+	// See https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format.
+	// Use of KeyLogWriter compromises security and should only be
+	// used for debugging.
+	KeyLogWriter io.Writer
+}
+
+func defaultConnectContextMaker() (context.Context, func()) {
+	return context.WithTimeout(context.Background(), 30*time.Second)
+}
+
+func (c *Config) connectContextMaker() (context.Context, func()) {
+	if c.ConnectContextMaker == nil {
+		return defaultConnectContextMaker()
+	}
+	return c.ConnectContextMaker()
+}
+
+const defaultMTU = 1200 // bytes
+
+// PSKCallback is called once we have the remote's PSKIdentityHint.
+// If the remote provided none it will be nil
+type PSKCallback func([]byte) ([]byte, error)
+
+// ClientAuthType declares the policy the server will follow for
+// TLS Client Authentication.
+type ClientAuthType int
+
+// ClientAuthType enums
+const (
+	NoClientCert ClientAuthType = iota
+	RequestClientCert
+	RequireAnyClientCert
+	VerifyClientCertIfGiven
+	RequireAndVerifyClientCert
+)
+
+// ExtendedMasterSecretType declares the policy the client and server
+// will follow for the Extended Master Secret extension
+type ExtendedMasterSecretType int
+
+// ExtendedMasterSecretType enums
+const (
+	RequestExtendedMasterSecret ExtendedMasterSecretType = iota
+	RequireExtendedMasterSecret
+	DisableExtendedMasterSecret
+)
+
+func validateConfig(config *Config) error {
+	switch {
+	case config == nil:
+		return errNoConfigProvided
+	case config.PSKIdentityHint != nil && config.PSK == nil:
+		return errIdentityNoPSK
+	}
+
+	for _, cert := range config.Certificates {
+		if cert.Certificate == nil {
+			return errInvalidCertificate
+		}
+		if cert.PrivateKey != nil {
+			switch cert.PrivateKey.(type) {
+			case ed25519.PrivateKey:
+			case *ecdsa.PrivateKey:
+			case *rsa.PrivateKey:
+			default:
+				return errInvalidPrivateKey
+			}
+		}
+	}
+
+	_, err := parseCipherSuites(config.CipherSuites, config.CustomCipherSuites, config.PSK == nil || len(config.Certificates) > 0, config.PSK != nil)
+	return err
+}

dtls-2.0.9/config_test.go

@@ -0,0 +1,119 @@
+package dtls
+
+import (
+	"crypto/dsa" //nolint
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"errors"
+	"testing"
+
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+)
+
+func TestValidateConfig(t *testing.T) {
+	// Empty config
+	if err := validateConfig(nil); !errors.Is(err, errNoConfigProvided) {
+		t.Fatalf("TestValidateConfig: Config validation error exp(%v) failed(%v)", errNoConfigProvided, err)
+	}
+
+	// PSK and Certificate, valid cipher suites
+	cert, err := selfsign.GenerateSelfSigned()
+	if err != nil {
+		t.Fatalf("TestValidateConfig: Config validation error(%v), self signed certificate not generated", err)
+		return
+	}
+	config := &Config{
+		CipherSuites: []CipherSuiteID{TLS_PSK_WITH_AES_128_CCM_8, TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+		PSK: func(hint []byte) ([]byte, error) {
+			return nil, nil
+		},
+		Certificates: []tls.Certificate{cert},
+	}
+	if err = validateConfig(config); err != nil {
+		t.Fatalf("TestValidateConfig: Client error exp(%v) failed(%v)", nil, err)
+	}
+
+	// PSK and Certificate, no PSK cipher suite
+	config = &Config{
+		CipherSuites: []CipherSuiteID{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+		PSK: func(hint []byte) ([]byte, error) {
+			return nil, nil
+		},
+		Certificates: []tls.Certificate{cert},
+	}
+	if err = validateConfig(config); !errors.Is(errNoAvailablePSKCipherSuite, err) {
+		t.Fatalf("TestValidateConfig: Client error exp(%v) failed(%v)", errNoAvailablePSKCipherSuite, err)
+	}
+
+	// PSK and Certificate, no non-PSK cipher suite
+	config = &Config{
+		CipherSuites: []CipherSuiteID{TLS_PSK_WITH_AES_128_CCM_8},
+		PSK: func(hint []byte) ([]byte, error) {
+			return nil, nil
+		},
+		Certificates: []tls.Certificate{cert},
+	}
+	if err = validateConfig(config); !errors.Is(errNoAvailableCertificateCipherSuite, err) {
+		t.Fatalf("TestValidateConfig: Client error exp(%v) failed(%v)", errNoAvailableCertificateCipherSuite, err)
+	}
+
+	// PSK identity hint with not PSK
+	config = &Config{
+		CipherSuites:    []CipherSuiteID{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+		PSK:             nil,
+		PSKIdentityHint: []byte{},
+	}
+	if err = validateConfig(config); !errors.Is(err, errIdentityNoPSK) {
+		t.Fatalf("TestValidateConfig: Client error exp(%v) failed(%v)", errIdentityNoPSK, err)
+	}
+
+	// Invalid private key
+	dsaPrivateKey := &dsa.PrivateKey{}
+	err = dsa.GenerateParameters(&dsaPrivateKey.Parameters, rand.Reader, dsa.L1024N160)
+	if err != nil {
+		t.Fatalf("TestValidateConfig: Config validation error(%v), DSA parameters not generated", err)
+		return
+	}
+	err = dsa.GenerateKey(dsaPrivateKey, rand.Reader)
+	if err != nil {
+		t.Fatalf("TestValidateConfig: Config validation error(%v), DSA private key not generated", err)
+		return
+	}
+	config = &Config{
+		CipherSuites: []CipherSuiteID{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+		Certificates: []tls.Certificate{{Certificate: cert.Certificate, PrivateKey: dsaPrivateKey}},
+	}
+	if err = validateConfig(config); !errors.Is(err, errInvalidPrivateKey) {
+		t.Fatalf("TestValidateConfig: Client error exp(%v) failed(%v)", errInvalidPrivateKey, err)
+	}
+
+	// PrivateKey without Certificate
+	config = &Config{
+		CipherSuites: []CipherSuiteID{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+		Certificates: []tls.Certificate{{PrivateKey: cert.PrivateKey}},
+	}
+	if err = validateConfig(config); !errors.Is(err, errInvalidCertificate) {
+		t.Fatalf("TestValidateConfig: Client error exp(%v) failed(%v)", errInvalidCertificate, err)
+	}
+
+	// Invalid cipher suites
+	config = &Config{CipherSuites: []CipherSuiteID{0x0000}}
+	if err = validateConfig(config); err == nil {
+		t.Fatal("TestValidateConfig: Client error expected with invalid CipherSuiteID")
+	}
+
+	// Valid config
+	rsaPrivateKey, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		t.Fatalf("TestValidateConfig: Config validation error(%v), RSA private key not generated", err)
+		return
+	}
+	config = &Config{
+		CipherSuites: []CipherSuiteID{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+		Certificates: []tls.Certificate{cert, {Certificate: cert.Certificate, PrivateKey: rsaPrivateKey}},
+	}
+	if err = validateConfig(config); err != nil {
+		t.Fatalf("TestValidateConfig: Client error exp(%v) failed(%v)", nil, err)
+	}
+}

dtls-2.0.9/conn.go

@@ -0,0 +1,979 @@
+package dtls
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/pion/dtls/v2/internal/closer"
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/crypto/signaturehash"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+	"github.com/pion/logging"
+	"github.com/pion/transport/connctx"
+	"github.com/pion/transport/deadline"
+	"github.com/pion/transport/replaydetector"
+)
+
+const (
+	initialTickerInterval = time.Second
+	cookieLength          = 20
+	defaultNamedCurve     = elliptic.X25519
+	inboundBufferSize     = 8192
+	// Default replay protection window is specified by RFC 6347 Section 4.1.2.6
+	defaultReplayProtectionWindow = 64
+)
+
+func invalidKeyingLabels() map[string]bool {
+	return map[string]bool{
+		"client finished": true,
+		"server finished": true,
+		"master secret":   true,
+		"key expansion":   true,
+	}
+}
+
+// Conn represents a DTLS connection
+type Conn struct {
+	lock           sync.RWMutex     // Internal lock (must not be public)
+	nextConn       connctx.ConnCtx  // Embedded Conn, typically a udpconn we read/write from
+	fragmentBuffer *fragmentBuffer  // out-of-order and missing fragment handling
+	handshakeCache *handshakeCache  // caching of handshake messages for verifyData generation
+	decrypted      chan interface{} // Decrypted Application Data or error, pull by calling `Read`
+
+	state State // Internal state
+
+	maximumTransmissionUnit int
+
+	handshakeCompletedSuccessfully atomic.Value
+
+	encryptedPackets [][]byte
+
+	connectionClosedByUser bool
+	closeLock              sync.Mutex
+	closed                 *closer.Closer
+	handshakeLoopsFinished sync.WaitGroup
+
+	readDeadline  *deadline.Deadline
+	writeDeadline *deadline.Deadline
+
+	log logging.LeveledLogger
+
+	reading               chan struct{}
+	handshakeRecv         chan chan struct{}
+	cancelHandshaker      func()
+	cancelHandshakeReader func()
+
+	fsm *handshakeFSM
+
+	replayProtectionWindow uint
+}
+
+func createConn(ctx context.Context, nextConn net.Conn, config *Config, isClient bool, initialState *State) (*Conn, error) {
+	err := validateConfig(config)
+	if err != nil {
+		return nil, err
+	}
+
+	if nextConn == nil {
+		return nil, errNilNextConn
+	}
+
+	cipherSuites, err := parseCipherSuites(config.CipherSuites, config.CustomCipherSuites, config.PSK == nil || len(config.Certificates) > 0, config.PSK != nil)
+	if err != nil {
+		return nil, err
+	}
+
+	signatureSchemes, err := signaturehash.ParseSignatureSchemes(config.SignatureSchemes, config.InsecureHashes)
+	if err != nil {
+		return nil, err
+	}
+
+	workerInterval := initialTickerInterval
+	if config.FlightInterval != 0 {
+		workerInterval = config.FlightInterval
+	}
+
+	loggerFactory := config.LoggerFactory
+	if loggerFactory == nil {
+		loggerFactory = logging.NewDefaultLoggerFactory()
+	}
+
+	logger := loggerFactory.NewLogger("dtls")
+
+	mtu := config.MTU
+	if mtu <= 0 {
+		mtu = defaultMTU
+	}
+
+	replayProtectionWindow := config.ReplayProtectionWindow
+	if replayProtectionWindow <= 0 {
+		replayProtectionWindow = defaultReplayProtectionWindow
+	}
+
+	c := &Conn{
+		nextConn:                connctx.New(nextConn),
+		fragmentBuffer:          newFragmentBuffer(),
+		handshakeCache:          newHandshakeCache(),
+		maximumTransmissionUnit: mtu,
+
+		decrypted: make(chan interface{}, 1),
+		log:       logger,
+
+		readDeadline:  deadline.New(),
+		writeDeadline: deadline.New(),
+
+		reading:          make(chan struct{}, 1),
+		handshakeRecv:    make(chan chan struct{}),
+		closed:           closer.NewCloser(),
+		cancelHandshaker: func() {},
+
+		replayProtectionWindow: uint(replayProtectionWindow),
+
+		state: State{
+			isClient: isClient,
+		},
+	}
+
+	c.setRemoteEpoch(0)
+	c.setLocalEpoch(0)
+
+	serverName := config.ServerName
+	// Use host from conn address when serverName is not provided
+	if isClient && serverName == "" && nextConn.RemoteAddr() != nil {
+		remoteAddr := nextConn.RemoteAddr().String()
+		var host string
+		host, _, err = net.SplitHostPort(remoteAddr)
+		if err != nil {
+			serverName = remoteAddr
+		} else {
+			serverName = host
+		}
+	}
+
+	hsCfg := &handshakeConfig{
+		localPSKCallback:            config.PSK,
+		localPSKIdentityHint:        config.PSKIdentityHint,
+		localCiscoCompatCallback:    config.CiscoCompat,
+		localCipherSuites:           cipherSuites,
+		localSignatureSchemes:       signatureSchemes,
+		extendedMasterSecret:        config.ExtendedMasterSecret,
+		localSRTPProtectionProfiles: config.SRTPProtectionProfiles,
+		serverName:                  serverName,
+		clientAuth:                  config.ClientAuth,
+		localCertificates:           config.Certificates,
+		insecureSkipVerify:          config.InsecureSkipVerify,
+		verifyPeerCertificate:       config.VerifyPeerCertificate,
+		rootCAs:                     config.RootCAs,
+		clientCAs:                   config.ClientCAs,
+		customCipherSuites:          config.CustomCipherSuites,
+		retransmitInterval:          workerInterval,
+		log:                         logger,
+		initialEpoch:                0,
+		keyLogWriter:                config.KeyLogWriter,
+	}
+
+	var initialFlight flightVal
+	var initialFSMState handshakeState
+
+	if initialState != nil {
+		if c.state.isClient {
+			initialFlight = flight5
+		} else {
+			initialFlight = flight6
+		}
+		initialFSMState = handshakeFinished
+
+		c.state = *initialState
+	} else {
+		if c.state.isClient {
+			initialFlight = flight1
+		} else {
+			initialFlight = flight0
+		}
+		initialFSMState = handshakePreparing
+	}
+	// Do handshake
+	if err := c.handshake(ctx, hsCfg, initialFlight, initialFSMState); err != nil {
+		return nil, err
+	}
+
+	c.log.Trace("Handshake Completed")
+
+	return c, nil
+}
+
+// Dial connects to the given network address and establishes a DTLS connection on top.
+// Connection handshake will timeout using ConnectContextMaker in the Config.
+// If you want to specify the timeout duration, use DialWithContext() instead.
+func Dial(network string, raddr *net.UDPAddr, config *Config) (*Conn, error) {
+	ctx, cancel := config.connectContextMaker()
+	defer cancel()
+
+	return DialWithContext(ctx, network, raddr, config)
+}
+
+// Client establishes a DTLS connection over an existing connection.
+// Connection handshake will timeout using ConnectContextMaker in the Config.
+// If you want to specify the timeout duration, use ClientWithContext() instead.
+func Client(conn net.Conn, config *Config) (*Conn, error) {
+	ctx, cancel := config.connectContextMaker()
+	defer cancel()
+
+	return ClientWithContext(ctx, conn, config)
+}
+
+// Server listens for incoming DTLS connections.
+// Connection handshake will timeout using ConnectContextMaker in the Config.
+// If you want to specify the timeout duration, use ServerWithContext() instead.
+func Server(conn net.Conn, config *Config) (*Conn, error) {
+	ctx, cancel := config.connectContextMaker()
+	defer cancel()
+
+	return ServerWithContext(ctx, conn, config)
+}
+
+// DialWithContext connects to the given network address and establishes a DTLS connection on top.
+func DialWithContext(ctx context.Context, network string, raddr *net.UDPAddr, config *Config) (*Conn, error) {
+	pConn, err := net.DialUDP(network, nil, raddr)
+	if err != nil {
+		return nil, err
+	}
+	return ClientWithContext(ctx, pConn, config)
+}
+
+// ClientWithContext establishes a DTLS connection over an existing connection.
+func ClientWithContext(ctx context.Context, conn net.Conn, config *Config) (*Conn, error) {
+	switch {
+	case config == nil:
+		return nil, errNoConfigProvided
+	case config.PSK != nil && config.PSKIdentityHint == nil:
+		return nil, errPSKAndIdentityMustBeSetForClient
+	}
+
+	return createConn(ctx, conn, config, true, nil)
+}
+
+// ServerWithContext listens for incoming DTLS connections.
+func ServerWithContext(ctx context.Context, conn net.Conn, config *Config) (*Conn, error) {
+	if config == nil {
+		return nil, errNoConfigProvided
+	}
+
+	return createConn(ctx, conn, config, false, nil)
+}
+
+// Read reads data from the connection.
+func (c *Conn) Read(p []byte) (n int, err error) {
+	if !c.isHandshakeCompletedSuccessfully() {
+		return 0, errHandshakeInProgress
+	}
+
+	select {
+	case <-c.readDeadline.Done():
+		return 0, errDeadlineExceeded
+	default:
+	}
+
+	for {
+		select {
+		case <-c.readDeadline.Done():
+			return 0, errDeadlineExceeded
+		case out, ok := <-c.decrypted:
+			if !ok {
+				return 0, io.EOF
+			}
+			switch val := out.(type) {
+			case ([]byte):
+				if len(p) < len(val) {
+					return 0, errBufferTooSmall
+				}
+				copy(p, val)
+				return len(val), nil
+			case (error):
+				return 0, val
+			}
+		}
+	}
+}
+
+// Write writes len(p) bytes from p to the DTLS connection
+func (c *Conn) Write(p []byte) (int, error) {
+	if c.isConnectionClosed() {
+		return 0, ErrConnClosed
+	}
+
+	select {
+	case <-c.writeDeadline.Done():
+		return 0, errDeadlineExceeded
+	default:
+	}
+
+	if !c.isHandshakeCompletedSuccessfully() {
+		return 0, errHandshakeInProgress
+	}
+
+	return len(p), c.writePackets(c.writeDeadline, []*packet{
+		{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Epoch:   c.getLocalEpoch(),
+					Version: protocol.Version1_2,
+				},
+				Content: &protocol.ApplicationData{
+					Data: p,
+				},
+			},
+			shouldEncrypt: true,
+		},
+	})
+}
+
+// Close closes the connection.
+func (c *Conn) Close() error {
+	err := c.close(true)
+	c.handshakeLoopsFinished.Wait()
+	return err
+}
+
+// ConnectionState returns basic DTLS details about the connection.
+// Note that this replaced the `Export` function of v1.
+func (c *Conn) ConnectionState() State {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	return *c.state.clone()
+}
+
+// SelectedSRTPProtectionProfile returns the selected SRTPProtectionProfile
+func (c *Conn) SelectedSRTPProtectionProfile() (SRTPProtectionProfile, bool) {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+
+	if c.state.srtpProtectionProfile == 0 {
+		return 0, false
+	}
+
+	return c.state.srtpProtectionProfile, true
+}
+
+func (c *Conn) writePackets(ctx context.Context, pkts []*packet) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	var rawPackets [][]byte
+
+	for _, p := range pkts {
+		if h, ok := p.record.Content.(*handshake.Handshake); ok {
+			handshakeRaw, err := p.record.Marshal()
+			if err != nil {
+				return err
+			}
+
+			c.log.Tracef("[handshake:%v] -> %s (epoch: %d, seq: %d)",
+				srvCliStr(c.state.isClient), h.Header.Type.String(),
+				p.record.Header.Epoch, h.Header.MessageSequence)
+			c.handshakeCache.push(handshakeRaw[recordlayer.HeaderSize:], p.record.Header.Epoch, h.Header.MessageSequence, h.Header.Type, c.state.isClient)
+
+			rawHandshakePackets, err := c.processHandshakePacket(p, h)
+			if err != nil {
+				return err
+			}
+			rawPackets = append(rawPackets, rawHandshakePackets...)
+		} else {
+			rawPacket, err := c.processPacket(p)
+			if err != nil {
+				return err
+			}
+			rawPackets = append(rawPackets, rawPacket)
+		}
+	}
+	if len(rawPackets) == 0 {
+		return nil
+	}
+	compactedRawPackets := c.compactRawPackets(rawPackets)
+
+	for _, compactedRawPackets := range compactedRawPackets {
+		if _, err := c.nextConn.WriteContext(ctx, compactedRawPackets); err != nil {
+			return netError(err)
+		}
+	}
+
+	return nil
+}
+
+func (c *Conn) compactRawPackets(rawPackets [][]byte) [][]byte {
+	combinedRawPackets := make([][]byte, 0)
+	currentCombinedRawPacket := make([]byte, 0)
+
+	for _, rawPacket := range rawPackets {
+		if len(currentCombinedRawPacket) > 0 && len(currentCombinedRawPacket)+len(rawPacket) >= c.maximumTransmissionUnit {
+			combinedRawPackets = append(combinedRawPackets, currentCombinedRawPacket)
+			currentCombinedRawPacket = []byte{}
+		}
+		currentCombinedRawPacket = append(currentCombinedRawPacket, rawPacket...)
+	}
+
+	combinedRawPackets = append(combinedRawPackets, currentCombinedRawPacket)
+
+	return combinedRawPackets
+}
+
+func (c *Conn) processPacket(p *packet) ([]byte, error) {
+	epoch := p.record.Header.Epoch
+	for len(c.state.localSequenceNumber) <= int(epoch) {
+		c.state.localSequenceNumber = append(c.state.localSequenceNumber, uint64(0))
+	}
+	seq := atomic.AddUint64(&c.state.localSequenceNumber[epoch], 1) - 1
+	if seq > recordlayer.MaxSequenceNumber {
+		// RFC 6347 Section 4.1.0
+		// The implementation must either abandon an association or rehandshake
+		// prior to allowing the sequence number to wrap.
+		return nil, errSequenceNumberOverflow
+	}
+	p.record.Header.SequenceNumber = seq
+
+	rawPacket, err := p.record.Marshal()
+	if err != nil {
+		return nil, err
+	}
+
+	if p.shouldEncrypt {
+		var err error
+		rawPacket, err = c.state.cipherSuite.Encrypt(p.record, rawPacket)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return rawPacket, nil
+}
+
+func (c *Conn) processHandshakePacket(p *packet, h *handshake.Handshake) ([][]byte, error) {
+	rawPackets := make([][]byte, 0)
+
+	handshakeFragments, err := c.fragmentHandshake(h)
+	if err != nil {
+		return nil, err
+	}
+	epoch := p.record.Header.Epoch
+	for len(c.state.localSequenceNumber) <= int(epoch) {
+		c.state.localSequenceNumber = append(c.state.localSequenceNumber, uint64(0))
+	}
+
+	for _, handshakeFragment := range handshakeFragments {
+		seq := atomic.AddUint64(&c.state.localSequenceNumber[epoch], 1) - 1
+		if seq > recordlayer.MaxSequenceNumber {
+			return nil, errSequenceNumberOverflow
+		}
+
+		recordlayerHeader := &recordlayer.Header{
+			Version:        p.record.Header.Version,
+			ContentType:    p.record.Header.ContentType,
+			ContentLen:     uint16(len(handshakeFragment)),
+			Epoch:          p.record.Header.Epoch,
+			SequenceNumber: seq,
+		}
+
+		recordlayerHeaderBytes, err := recordlayerHeader.Marshal()
+		if err != nil {
+			return nil, err
+		}
+
+		p.record.Header = *recordlayerHeader
+
+		rawPacket := append(recordlayerHeaderBytes, handshakeFragment...)
+		if p.shouldEncrypt {
+			var err error
+			rawPacket, err = c.state.cipherSuite.Encrypt(p.record, rawPacket)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		rawPackets = append(rawPackets, rawPacket)
+	}
+
+	return rawPackets, nil
+}
+
+func (c *Conn) fragmentHandshake(h *handshake.Handshake) ([][]byte, error) {
+	content, err := h.Message.Marshal()
+	if err != nil {
+		return nil, err
+	}
+
+	fragmentedHandshakes := make([][]byte, 0)
+
+	contentFragments := splitBytes(content, c.maximumTransmissionUnit)
+	if len(contentFragments) == 0 {
+		contentFragments = [][]byte{
+			{},
+		}
+	}
+
+	offset := 0
+	for _, contentFragment := range contentFragments {
+		contentFragmentLen := len(contentFragment)
+
+		headerFragment := &handshake.Header{
+			Type:            h.Header.Type,
+			Length:          h.Header.Length,
+			MessageSequence: h.Header.MessageSequence,
+			FragmentOffset:  uint32(offset),
+			FragmentLength:  uint32(contentFragmentLen),
+		}
+
+		offset += contentFragmentLen
+
+		headerFragmentRaw, err := headerFragment.Marshal()
+		if err != nil {
+			return nil, err
+		}
+
+		fragmentedHandshake := append(headerFragmentRaw, contentFragment...)
+		fragmentedHandshakes = append(fragmentedHandshakes, fragmentedHandshake)
+	}
+
+	return fragmentedHandshakes, nil
+}
+
+var poolReadBuffer = sync.Pool{ //nolint:gochecknoglobals
+	New: func() interface{} {
+		b := make([]byte, inboundBufferSize)
+		return &b
+	},
+}
+
+func (c *Conn) readAndBuffer(ctx context.Context) error {
+	bufptr := poolReadBuffer.Get().(*[]byte)
+	defer poolReadBuffer.Put(bufptr)
+
+	b := *bufptr
+	i, err := c.nextConn.ReadContext(ctx, b)
+	if err != nil {
+		return netError(err)
+	}
+
+	pkts, err := recordlayer.UnpackDatagram(b[:i])
+	if err != nil {
+		return err
+	}
+
+	var hasHandshake bool
+	for _, p := range pkts {
+		hs, alert, err := c.handleIncomingPacket(p, true)
+		if alert != nil {
+			if alertErr := c.notify(ctx, alert.Level, alert.Description); alertErr != nil {
+				if err == nil {
+					err = alertErr
+				}
+			}
+		}
+		if hs {
+			hasHandshake = true
+		}
+		switch e := err.(type) {
+		case nil:
+		case *errAlert:
+			if e.IsFatalOrCloseNotify() {
+				return e
+			}
+		default:
+			return e
+		}
+	}
+	if hasHandshake {
+		done := make(chan struct{})
+		select {
+		case c.handshakeRecv <- done:
+			// If the other party may retransmit the flight,
+			// we should respond even if it not a new message.
+			<-done
+		case <-c.fsm.Done():
+		}
+	}
+	return nil
+}
+
+func (c *Conn) handleQueuedPackets(ctx context.Context) error {
+	pkts := c.encryptedPackets
+	c.encryptedPackets = nil
+
+	for _, p := range pkts {
+		_, alert, err := c.handleIncomingPacket(p, false) // don't re-enqueue
+		if alert != nil {
+			if alertErr := c.notify(ctx, alert.Level, alert.Description); alertErr != nil {
+				if err == nil {
+					err = alertErr
+				}
+			}
+		}
+		switch e := err.(type) {
+		case nil:
+		case *errAlert:
+			if e.IsFatalOrCloseNotify() {
+				return e
+			}
+		default:
+			return e
+		}
+	}
+	return nil
+}
+
+func (c *Conn) handleIncomingPacket(buf []byte, enqueue bool) (bool, *alert.Alert, error) { //nolint:gocognit
+	h := &recordlayer.Header{}
+	if err := h.Unmarshal(buf); err != nil {
+		// Decode error must be silently discarded
+		// [RFC6347 Section-4.1.2.7]
+		c.log.Debugf("discarded broken packet: %v", err)
+		return false, nil, nil
+	}
+
+	// Validate epoch
+	remoteEpoch := c.getRemoteEpoch()
+	if h.Epoch > remoteEpoch {
+		if h.Epoch > remoteEpoch+1 {
+			c.log.Debugf("discarded future packet (epoch: %d, seq: %d)",
+				h.Epoch, h.SequenceNumber,
+			)
+			return false, nil, nil
+		}
+		if enqueue {
+			c.log.Debug("received packet of next epoch, queuing packet")
+			c.encryptedPackets = append(c.encryptedPackets, buf)
+		}
+		return false, nil, nil
+	}
+
+	// Anti-replay protection
+	for len(c.state.replayDetector) <= int(h.Epoch) {
+		c.state.replayDetector = append(c.state.replayDetector,
+			replaydetector.New(c.replayProtectionWindow, recordlayer.MaxSequenceNumber),
+		)
+	}
+	markPacketAsValid, ok := c.state.replayDetector[int(h.Epoch)].Check(h.SequenceNumber)
+	if !ok {
+		c.log.Debugf("discarded duplicated packet (epoch: %d, seq: %d)",
+			h.Epoch, h.SequenceNumber,
+		)
+		return false, nil, nil
+	}
+
+	// Decrypt
+	if h.Epoch != 0 {
+		if c.state.cipherSuite == nil || !c.state.cipherSuite.IsInitialized() {
+			if enqueue {
+				c.encryptedPackets = append(c.encryptedPackets, buf)
+				c.log.Debug("handshake not finished, queuing packet")
+			}
+			return false, nil, nil
+		}
+
+		var err error
+		buf, err = c.state.cipherSuite.Decrypt(buf)
+		if err != nil {
+			c.log.Debugf("%s: decrypt failed: %s", srvCliStr(c.state.isClient), err)
+			return false, nil, nil
+		}
+	}
+
+	isHandshake, err := c.fragmentBuffer.push(append([]byte{}, buf...))
+	if err != nil {
+		// Decode error must be silently discarded
+		// [RFC6347 Section-4.1.2.7]
+		c.log.Debugf("defragment failed: %s", err)
+		return false, nil, nil
+	} else if isHandshake {
+		markPacketAsValid()
+		for out, epoch := c.fragmentBuffer.pop(); out != nil; out, epoch = c.fragmentBuffer.pop() {
+			rawHandshake := &handshake.Handshake{}
+			if err := rawHandshake.Unmarshal(out); err != nil {
+				c.log.Debugf("%s: handshake parse failed: %s", srvCliStr(c.state.isClient), err)
+				continue
+			}
+
+			_ = c.handshakeCache.push(out, epoch, rawHandshake.Header.MessageSequence, rawHandshake.Header.Type, !c.state.isClient)
+		}
+
+		return true, nil, nil
+	}
+
+	r := &recordlayer.RecordLayer{}
+	if err := r.Unmarshal(buf); err != nil {
+		return false, &alert.Alert{Level: alert.Fatal, Description: alert.DecodeError}, err
+	}
+
+	switch content := r.Content.(type) {
+	case *alert.Alert:
+		c.log.Tracef("%s: <- %s", srvCliStr(c.state.isClient), content.String())
+		var a *alert.Alert
+		if content.Description == alert.CloseNotify {
+			// Respond with a close_notify [RFC5246 Section 7.2.1]
+			a = &alert.Alert{Level: alert.Warning, Description: alert.CloseNotify}
+		}
+		markPacketAsValid()
+		return false, a, &errAlert{content}
+	case *protocol.ChangeCipherSpec:
+		if c.state.cipherSuite == nil || !c.state.cipherSuite.IsInitialized() {
+			if enqueue {
+				c.encryptedPackets = append(c.encryptedPackets, buf)
+				c.log.Debugf("CipherSuite not initialized, queuing packet")
+			}
+			return false, nil, nil
+		}
+
+		newRemoteEpoch := h.Epoch + 1
+		c.log.Tracef("%s: <- ChangeCipherSpec (epoch: %d)", srvCliStr(c.state.isClient), newRemoteEpoch)
+
+		if c.getRemoteEpoch()+1 == newRemoteEpoch {
+			c.setRemoteEpoch(newRemoteEpoch)
+			markPacketAsValid()
+		}
+	case *protocol.ApplicationData:
+		if h.Epoch == 0 {
+			return false, &alert.Alert{Level: alert.Fatal, Description: alert.UnexpectedMessage}, errApplicationDataEpochZero
+		}
+
+		markPacketAsValid()
+
+		select {
+		case c.decrypted <- content.Data:
+		case <-c.closed.Done():
+		}
+
+	default:
+		return false, &alert.Alert{Level: alert.Fatal, Description: alert.UnexpectedMessage}, fmt.Errorf("%w: %d", errUnhandledContextType, content.ContentType())
+	}
+	return false, nil, nil
+}
+
+func (c *Conn) recvHandshake() <-chan chan struct{} {
+	return c.handshakeRecv
+}
+
+func (c *Conn) notify(ctx context.Context, level alert.Level, desc alert.Description) error {
+	return c.writePackets(ctx, []*packet{
+		{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Epoch:   c.getLocalEpoch(),
+					Version: protocol.Version1_2,
+				},
+				Content: &alert.Alert{
+					Level:       level,
+					Description: desc,
+				},
+			},
+			shouldEncrypt: c.isHandshakeCompletedSuccessfully(),
+		},
+	})
+}
+
+func (c *Conn) setHandshakeCompletedSuccessfully() {
+	c.handshakeCompletedSuccessfully.Store(struct{ bool }{true})
+}
+
+func (c *Conn) isHandshakeCompletedSuccessfully() bool {
+	boolean, _ := c.handshakeCompletedSuccessfully.Load().(struct{ bool })
+	return boolean.bool
+}
+
+func (c *Conn) handshake(ctx context.Context, cfg *handshakeConfig, initialFlight flightVal, initialState handshakeState) error { //nolint:gocognit
+	c.fsm = newHandshakeFSM(&c.state, c.handshakeCache, cfg, initialFlight)
+
+	done := make(chan struct{})
+	ctxRead, cancelRead := context.WithCancel(context.Background())
+	c.cancelHandshakeReader = cancelRead
+	cfg.onFlightState = func(f flightVal, s handshakeState) {
+		if s == handshakeFinished && !c.isHandshakeCompletedSuccessfully() {
+			c.setHandshakeCompletedSuccessfully()
+			close(done)
+		}
+	}
+
+	ctxHs, cancel := context.WithCancel(context.Background())
+	c.cancelHandshaker = cancel
+
+	firstErr := make(chan error, 1)
+
+	c.handshakeLoopsFinished.Add(2)
+
+	// Handshake routine should be live until close.
+	// The other party may request retransmission of the last flight to cope with packet drop.
+	go func() {
+		defer c.handshakeLoopsFinished.Done()
+		err := c.fsm.Run(ctxHs, c, initialState)
+		if !errors.Is(err, context.Canceled) {
+			select {
+			case firstErr <- err:
+			default:
+			}
+		}
+	}()
+	go func() {
+		defer func() {
+			// Escaping read loop.
+			// It's safe to close decrypted channnel now.
+			close(c.decrypted)
+
+			// Force stop handshaker when the underlying connection is closed.
+			cancel()
+		}()
+		defer c.handshakeLoopsFinished.Done()
+		for {
+			if err := c.readAndBuffer(ctxRead); err != nil {
+				switch e := err.(type) {
+				case *errAlert:
+					if !e.IsFatalOrCloseNotify() {
+						if c.isHandshakeCompletedSuccessfully() {
+							// Pass the error to Read()
+							select {
+							case c.decrypted <- err:
+							case <-c.closed.Done():
+							}
+						}
+						continue // non-fatal alert must not stop read loop
+					}
+				case error:
+					switch err {
+					case context.DeadlineExceeded, context.Canceled, io.EOF:
+					default:
+						if c.isHandshakeCompletedSuccessfully() {
+							// Keep read loop and pass the read error to Read()
+							select {
+							case c.decrypted <- err:
+							case <-c.closed.Done():
+							}
+							continue // non-fatal alert must not stop read loop
+						}
+					}
+				}
+				select {
+				case firstErr <- err:
+				default:
+				}
+
+				if e, ok := err.(*errAlert); ok {
+					if e.IsFatalOrCloseNotify() {
+						_ = c.close(false)
+					}
+				}
+				return
+			}
+		}
+	}()
+
+	select {
+	case err := <-firstErr:
+		cancelRead()
+		cancel()
+		return c.translateHandshakeCtxError(err)
+	case <-ctx.Done():
+		cancelRead()
+		cancel()
+		return c.translateHandshakeCtxError(ctx.Err())
+	case <-done:
+		return nil
+	}
+}
+
+func (c *Conn) translateHandshakeCtxError(err error) error {
+	if err == nil {
+		return nil
+	}
+	if errors.Is(err, context.Canceled) && c.isHandshakeCompletedSuccessfully() {
+		return nil
+	}
+	return &HandshakeError{Err: err}
+}
+
+func (c *Conn) close(byUser bool) error {
+	c.cancelHandshaker()
+	c.cancelHandshakeReader()
+
+	if c.isHandshakeCompletedSuccessfully() && byUser {
+		// Discard error from notify() to return non-error on the first user call of Close()
+		// even if the underlying connection is already closed.
+		_ = c.notify(context.Background(), alert.Warning, alert.CloseNotify)
+	}
+
+	c.closeLock.Lock()
+	// Don't return ErrConnClosed at the first time of the call from user.
+	closedByUser := c.connectionClosedByUser
+	if byUser {
+		c.connectionClosedByUser = true
+	}
+	c.closed.Close()
+	c.closeLock.Unlock()
+
+	if closedByUser {
+		return ErrConnClosed
+	}
+
+	return c.nextConn.Close()
+}
+
+func (c *Conn) isConnectionClosed() bool {
+	select {
+	case <-c.closed.Done():
+		return true
+	default:
+		return false
+	}
+}
+
+func (c *Conn) setLocalEpoch(epoch uint16) {
+	c.state.localEpoch.Store(epoch)
+}
+
+func (c *Conn) getLocalEpoch() uint16 {
+	return c.state.localEpoch.Load().(uint16)
+}
+
+func (c *Conn) setRemoteEpoch(epoch uint16) {
+	c.state.remoteEpoch.Store(epoch)
+}
+
+func (c *Conn) getRemoteEpoch() uint16 {
+	return c.state.remoteEpoch.Load().(uint16)
+}
+
+// LocalAddr implements net.Conn.LocalAddr
+func (c *Conn) LocalAddr() net.Addr {
+	return c.nextConn.LocalAddr()
+}
+
+// RemoteAddr implements net.Conn.RemoteAddr
+func (c *Conn) RemoteAddr() net.Addr {
+	return c.nextConn.RemoteAddr()
+}
+
+// SetDeadline implements net.Conn.SetDeadline
+func (c *Conn) SetDeadline(t time.Time) error {
+	c.readDeadline.Set(t)
+	return c.SetWriteDeadline(t)
+}
+
+// SetReadDeadline implements net.Conn.SetReadDeadline
+func (c *Conn) SetReadDeadline(t time.Time) error {
+	c.readDeadline.Set(t)
+	// Read deadline is fully managed by this layer.
+	// Don't set read deadline to underlying connection.
+	return nil
+}
+
+// SetWriteDeadline implements net.Conn.SetWriteDeadline
+func (c *Conn) SetWriteDeadline(t time.Time) error {
+	c.writeDeadline.Set(t)
+	// Write deadline is also fully managed by this layer.
+	return nil
+}

dtls-2.0.9/conn_go_test.go

@@ -0,0 +1,169 @@
+// +build !js
+
+package dtls
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2/internal/net/dpipe"
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+	"github.com/pion/transport/test"
+)
+
+func TestContextConfig(t *testing.T) {
+	// Limit runtime in case of deadlocks
+	lim := test.TimeOut(time.Second * 20)
+	defer lim.Stop()
+
+	report := test.CheckRoutines(t)
+	defer report()
+
+	addrListen, err := net.ResolveUDPAddr("udp", "localhost:0")
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
+	// Dummy listener
+	listen, err := net.ListenUDP("udp", addrListen)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer func() {
+		_ = listen.Close()
+	}()
+	addr := listen.LocalAddr().(*net.UDPAddr)
+
+	cert, err := selfsign.GenerateSelfSigned()
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	config := &Config{
+		ConnectContextMaker: func() (context.Context, func()) {
+			return context.WithTimeout(context.Background(), 40*time.Millisecond)
+		},
+		Certificates: []tls.Certificate{cert},
+	}
+
+	dials := map[string]struct {
+		f     func() (func() (net.Conn, error), func())
+		order []byte
+	}{
+		"Dial": {
+			f: func() (func() (net.Conn, error), func()) {
+				return func() (net.Conn, error) {
+						return Dial("udp", addr, config)
+					}, func() {
+					}
+			},
+			order: []byte{0, 1, 2},
+		},
+		"DialWithContext": {
+			f: func() (func() (net.Conn, error), func()) {
+				ctx, cancel := context.WithTimeout(context.Background(), 80*time.Millisecond)
+				return func() (net.Conn, error) {
+						return DialWithContext(ctx, "udp", addr, config)
+					}, func() {
+						cancel()
+					}
+			},
+			order: []byte{0, 2, 1},
+		},
+		"Client": {
+			f: func() (func() (net.Conn, error), func()) {
+				ca, _ := dpipe.Pipe()
+				return func() (net.Conn, error) {
+						return Client(ca, config)
+					}, func() {
+						_ = ca.Close()
+					}
+			},
+			order: []byte{0, 1, 2},
+		},
+		"ClientWithContext": {
+			f: func() (func() (net.Conn, error), func()) {
+				ctx, cancel := context.WithTimeout(context.Background(), 80*time.Millisecond)
+				ca, _ := dpipe.Pipe()
+				return func() (net.Conn, error) {
+						return ClientWithContext(ctx, ca, config)
+					}, func() {
+						cancel()
+						_ = ca.Close()
+					}
+			},
+			order: []byte{0, 2, 1},
+		},
+		"Server": {
+			f: func() (func() (net.Conn, error), func()) {
+				ca, _ := dpipe.Pipe()
+				return func() (net.Conn, error) {
+						return Server(ca, config)
+					}, func() {
+						_ = ca.Close()
+					}
+			},
+			order: []byte{0, 1, 2},
+		},
+		"ServerWithContext": {
+			f: func() (func() (net.Conn, error), func()) {
+				ctx, cancel := context.WithTimeout(context.Background(), 80*time.Millisecond)
+				ca, _ := dpipe.Pipe()
+				return func() (net.Conn, error) {
+						return ServerWithContext(ctx, ca, config)
+					}, func() {
+						cancel()
+						_ = ca.Close()
+					}
+			},
+			order: []byte{0, 2, 1},
+		},
+	}
+
+	for name, dial := range dials {
+		dial := dial
+		t.Run(name, func(t *testing.T) {
+			done := make(chan struct{})
+
+			go func() {
+				d, cancel := dial.f()
+				conn, err := d()
+				defer cancel()
+				if netErr, ok := err.(net.Error); !ok || !netErr.Timeout() {
+					t.Errorf("Client error exp(Temporary network error) failed(%v)", err)
+					close(done)
+					return
+				}
+				done <- struct{}{}
+				if err == nil {
+					_ = conn.Close()
+				}
+			}()
+
+			var order []byte
+			early := time.After(20 * time.Millisecond)
+			late := time.After(60 * time.Millisecond)
+			func() {
+				for len(order) < 3 {
+					select {
+					case <-early:
+						order = append(order, 0)
+					case _, ok := <-done:
+						if !ok {
+							return
+						}
+						order = append(order, 1)
+					case <-late:
+						order = append(order, 2)
+					}
+				}
+			}()
+			if !bytes.Equal(dial.order, order) {
+				t.Errorf("Invalid cancel timing, expected: %v, got: %v", dial.order, order)
+			}
+		})
+	}
+}

dtls-2.0.9/crypto.go

@@ -0,0 +1,221 @@
+package dtls
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/asn1"
+	"encoding/binary"
+	"math/big"
+	"time"
+
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/crypto/hash"
+)
+
+type ecdsaSignature struct {
+	R, S *big.Int
+}
+
+func valueKeyMessage(clientRandom, serverRandom, publicKey []byte, namedCurve elliptic.Curve) []byte {
+	serverECDHParams := make([]byte, 4)
+	serverECDHParams[0] = 3 // named curve
+	binary.BigEndian.PutUint16(serverECDHParams[1:], uint16(namedCurve))
+	serverECDHParams[3] = byte(len(publicKey))
+
+	plaintext := []byte{}
+	plaintext = append(plaintext, clientRandom...)
+	plaintext = append(plaintext, serverRandom...)
+	plaintext = append(plaintext, serverECDHParams...)
+	plaintext = append(plaintext, publicKey...)
+
+	return plaintext
+}
+
+// If the client provided a "signature_algorithms" extension, then all
+// certificates provided by the server MUST be signed by a
+// hash/signature algorithm pair that appears in that extension
+//
+// https://tools.ietf.org/html/rfc5246#section-7.4.2
+func generateKeySignature(clientRandom, serverRandom, publicKey []byte, namedCurve elliptic.Curve, privateKey crypto.PrivateKey, hashAlgorithm hash.Algorithm) ([]byte, error) {
+	msg := valueKeyMessage(clientRandom, serverRandom, publicKey, namedCurve)
+	switch p := privateKey.(type) {
+	case ed25519.PrivateKey:
+		// https://crypto.stackexchange.com/a/55483
+		return p.Sign(rand.Reader, msg, crypto.Hash(0))
+	case *ecdsa.PrivateKey:
+		hashed := hashAlgorithm.Digest(msg)
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	case *rsa.PrivateKey:
+		hashed := hashAlgorithm.Digest(msg)
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	}
+
+	return nil, errKeySignatureGenerateUnimplemented
+}
+
+func verifyKeySignature(message, remoteKeySignature []byte, hashAlgorithm hash.Algorithm, rawCertificates [][]byte) error { //nolint:dupl
+	if len(rawCertificates) == 0 {
+		return errLengthMismatch
+	}
+	certificate, err := x509.ParseCertificate(rawCertificates[0])
+	if err != nil {
+		return err
+	}
+
+	switch p := certificate.PublicKey.(type) {
+	case ed25519.PublicKey:
+		if ok := ed25519.Verify(p, message, remoteKeySignature); !ok {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *ecdsa.PublicKey:
+		ecdsaSig := &ecdsaSignature{}
+		if _, err := asn1.Unmarshal(remoteKeySignature, ecdsaSig); err != nil {
+			return err
+		}
+		if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 {
+			return errInvalidECDSASignature
+		}
+		hashed := hashAlgorithm.Digest(message)
+		if !ecdsa.Verify(p, hashed, ecdsaSig.R, ecdsaSig.S) {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *rsa.PublicKey:
+		switch certificate.SignatureAlgorithm {
+		case x509.SHA1WithRSA, x509.SHA256WithRSA, x509.SHA384WithRSA, x509.SHA512WithRSA:
+			hashed := hashAlgorithm.Digest(message)
+			return rsa.VerifyPKCS1v15(p, hashAlgorithm.CryptoHash(), hashed, remoteKeySignature)
+		default:
+			return errKeySignatureVerifyUnimplemented
+		}
+	}
+
+	return errKeySignatureVerifyUnimplemented
+}
+
+// If the server has sent a CertificateRequest message, the client MUST send the Certificate
+// message.  The ClientKeyExchange message is now sent, and the content
+// of that message will depend on the public key algorithm selected
+// between the ClientHello and the ServerHello.  If the client has sent
+// a certificate with signing ability, a digitally-signed
+// CertificateVerify message is sent to explicitly verify possession of
+// the private key in the certificate.
+// https://tools.ietf.org/html/rfc5246#section-7.3
+func generateCertificateVerify(handshakeBodies []byte, privateKey crypto.PrivateKey, hashAlgorithm hash.Algorithm) ([]byte, error) {
+	h := sha256.New()
+	if _, err := h.Write(handshakeBodies); err != nil {
+		return nil, err
+	}
+	hashed := h.Sum(nil)
+
+	switch p := privateKey.(type) {
+	case ed25519.PrivateKey:
+		// https://crypto.stackexchange.com/a/55483
+		return p.Sign(rand.Reader, hashed, crypto.Hash(0))
+	case *ecdsa.PrivateKey:
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	case *rsa.PrivateKey:
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	}
+
+	return nil, errInvalidSignatureAlgorithm
+}
+
+func verifyCertificateVerify(handshakeBodies []byte, hashAlgorithm hash.Algorithm, remoteKeySignature []byte, rawCertificates [][]byte) error { //nolint:dupl
+	if len(rawCertificates) == 0 {
+		return errLengthMismatch
+	}
+	certificate, err := x509.ParseCertificate(rawCertificates[0])
+	if err != nil {
+		return err
+	}
+
+	switch p := certificate.PublicKey.(type) {
+	case ed25519.PublicKey:
+		if ok := ed25519.Verify(p, handshakeBodies, remoteKeySignature); !ok {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *ecdsa.PublicKey:
+		ecdsaSig := &ecdsaSignature{}
+		if _, err := asn1.Unmarshal(remoteKeySignature, ecdsaSig); err != nil {
+			return err
+		}
+		if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 {
+			return errInvalidECDSASignature
+		}
+		hash := hashAlgorithm.Digest(handshakeBodies)
+		if !ecdsa.Verify(p, hash, ecdsaSig.R, ecdsaSig.S) {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *rsa.PublicKey:
+		switch certificate.SignatureAlgorithm {
+		case x509.SHA1WithRSA, x509.SHA256WithRSA, x509.SHA384WithRSA, x509.SHA512WithRSA:
+			hash := hashAlgorithm.Digest(handshakeBodies)
+			return rsa.VerifyPKCS1v15(p, hashAlgorithm.CryptoHash(), hash, remoteKeySignature)
+		default:
+			return errKeySignatureVerifyUnimplemented
+		}
+	}
+
+	return errKeySignatureVerifyUnimplemented
+}
+
+func loadCerts(rawCertificates [][]byte) ([]*x509.Certificate, error) {
+	if len(rawCertificates) == 0 {
+		return nil, errLengthMismatch
+	}
+
+	certs := make([]*x509.Certificate, 0, len(rawCertificates))
+	for _, rawCert := range rawCertificates {
+		cert, err := x509.ParseCertificate(rawCert)
+		if err != nil {
+			return nil, err
+		}
+		certs = append(certs, cert)
+	}
+	return certs, nil
+}
+
+func verifyClientCert(rawCertificates [][]byte, roots *x509.CertPool) (chains [][]*x509.Certificate, err error) {
+	certificate, err := loadCerts(rawCertificates)
+	if err != nil {
+		return nil, err
+	}
+	intermediateCAPool := x509.NewCertPool()
+	for _, cert := range certificate[1:] {
+		intermediateCAPool.AddCert(cert)
+	}
+	opts := x509.VerifyOptions{
+		Roots:         roots,
+		CurrentTime:   time.Now(),
+		Intermediates: intermediateCAPool,
+		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+	}
+	return certificate[0].Verify(opts)
+}
+
+func verifyServerCert(rawCertificates [][]byte, roots *x509.CertPool, serverName string) (chains [][]*x509.Certificate, err error) {
+	certificate, err := loadCerts(rawCertificates)
+	if err != nil {
+		return nil, err
+	}
+	intermediateCAPool := x509.NewCertPool()
+	for _, cert := range certificate[1:] {
+		intermediateCAPool.AddCert(cert)
+	}
+	opts := x509.VerifyOptions{
+		Roots:         roots,
+		CurrentTime:   time.Now(),
+		DNSName:       serverName,
+		Intermediates: intermediateCAPool,
+	}
+	return certificate[0].Verify(opts)
+}

dtls-2.0.9/crypto_test.go

@@ -0,0 +1,73 @@
+package dtls
+
+import (
+	"bytes"
+	"crypto/x509"
+	"encoding/pem"
+	"testing"
+
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/crypto/hash"
+)
+
+const rawPrivateKey = `
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+`
+
+func TestGenerateKeySignature(t *testing.T) {
+	block, _ := pem.Decode([]byte(rawPrivateKey))
+	key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		t.Error(err)
+	}
+
+	clientRandom := []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f}
+	serverRandom := []byte{0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f}
+	publicKey := []byte{0x20, 0x9f, 0xd7, 0xad, 0x6d, 0xcf, 0xf4, 0x29, 0x8d, 0xd3, 0xf9, 0x6d, 0x5b, 0x1b, 0x2a, 0xf9, 0x10, 0xa0, 0x53, 0x5b, 0x14, 0x88, 0xd7, 0xf8, 0xfa, 0xbb, 0x34, 0x9a, 0x98, 0x28, 0x80, 0xb6, 0x15}
+	expectedSignature := []byte{
+		0x6f, 0x47, 0x97, 0x85, 0xcc, 0x76, 0x50, 0x93, 0xbd, 0xe2, 0x6a, 0x69, 0x0b, 0xc3, 0x03, 0xd1, 0xb7, 0xe4, 0xab, 0x88, 0x7b, 0xa6, 0x52, 0x80, 0xdf,
+		0xaa, 0x25, 0x7a, 0xdb, 0x29, 0x32, 0xe4, 0xd8, 0x28, 0x28, 0xb3, 0xe8, 0x04, 0x3c, 0x38, 0x16, 0xfc, 0x78, 0xe9, 0x15, 0x7b, 0xc5, 0xbd, 0x7d, 0xfc,
+		0xcd, 0x83, 0x00, 0x57, 0x4a, 0x3c, 0x23, 0x85, 0x75, 0x6b, 0x37, 0xd5, 0x89, 0x72, 0x73, 0xf0, 0x44, 0x8c, 0x00, 0x70, 0x1f, 0x6e, 0xa2, 0x81, 0xd0,
+		0x09, 0xc5, 0x20, 0x36, 0xab, 0x23, 0x09, 0x40, 0x1f, 0x4d, 0x45, 0x96, 0x62, 0xbb, 0x81, 0xb0, 0x30, 0x72, 0xad, 0x3a, 0x0a, 0xac, 0x31, 0x63, 0x40,
+		0x52, 0x0a, 0x27, 0xf3, 0x34, 0xde, 0x27, 0x7d, 0xb7, 0x54, 0xff, 0x0f, 0x9f, 0x5a, 0xfe, 0x07, 0x0f, 0x4e, 0x9f, 0x53, 0x04, 0x34, 0x62, 0xf4, 0x30,
+		0x74, 0x83, 0x35, 0xfc, 0xe4, 0x7e, 0xbf, 0x5a, 0xc4, 0x52, 0xd0, 0xea, 0xf9, 0x61, 0x4e, 0xf5, 0x1c, 0x0e, 0x58, 0x02, 0x71, 0xfb, 0x1f, 0x34, 0x55,
+		0xe8, 0x36, 0x70, 0x3c, 0xc1, 0xcb, 0xc9, 0xb7, 0xbb, 0xb5, 0x1c, 0x44, 0x9a, 0x6d, 0x88, 0x78, 0x98, 0xd4, 0x91, 0x2e, 0xeb, 0x98, 0x81, 0x23, 0x30,
+		0x73, 0x39, 0x43, 0xd5, 0xbb, 0x70, 0x39, 0xba, 0x1f, 0xdb, 0x70, 0x9f, 0x91, 0x83, 0x56, 0xc2, 0xde, 0xed, 0x17, 0x6d, 0x2c, 0x3e, 0x21, 0xea, 0x36,
+		0xb4, 0x91, 0xd8, 0x31, 0x05, 0x60, 0x90, 0xfd, 0xc6, 0x74, 0xa9, 0x7b, 0x18, 0xfc, 0x1c, 0x6a, 0x1c, 0x6e, 0xec, 0xd3, 0xc1, 0xc0, 0x0d, 0x11, 0x25,
+		0x48, 0x37, 0x3d, 0x45, 0x11, 0xa2, 0x31, 0x14, 0x0a, 0x66, 0x9f, 0xd8, 0xac, 0x74, 0xa2, 0xcd, 0xc8, 0x79, 0xb3, 0x9e, 0xc6, 0x66, 0x25, 0xcf, 0x2c,
+		0x87, 0x5e, 0x5c, 0x36, 0x75, 0x86,
+	}
+
+	signature, err := generateKeySignature(clientRandom, serverRandom, publicKey, elliptic.X25519, key, hash.SHA256)
+	if err != nil {
+		t.Error(err)
+	} else if !bytes.Equal(expectedSignature, signature) {
+		t.Errorf("Signature generation failed \nexp % 02x \nactual % 02x ", expectedSignature, signature)
+	}
+}

dtls-2.0.9/dtls.go

@@ -0,0 +1,2 @@
+// Package dtls implements Datagram Transport Layer Security (DTLS) 1.2
+package dtls

dtls-2.0.9/e2e/Dockerfile

@@ -0,0 +1,11 @@
+FROM golang:1.14-alpine3.11
+
+RUN apk add --no-cache \
+  openssl
+
+ENV CGO_ENABLED=0
+
+COPY . /go/src/github.com/pion/dtls
+WORKDIR /go/src/github.com/pion/dtls/e2e
+
+CMD ["go", "test", "-tags=openssl", "-v", "."]

dtls-2.0.9/e2e/e2e.go

@@ -0,0 +1,2 @@
+// Package e2e contains end to end tests for pion/dtls
+package e2e

dtls-2.0.9/e2e/e2e_lossy_test.go

@@ -0,0 +1,207 @@
+package e2e
+
+import (
+	"crypto/tls"
+	"fmt"
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+	transportTest "github.com/pion/transport/test"
+)
+
+const (
+	flightInterval   = time.Millisecond * 100
+	lossyTestTimeout = 30 * time.Second
+)
+
+/*
+  DTLS Client/Server over a lossy transport, just asserts it can handle at increasing increments
+*/
+func TestPionE2ELossy(t *testing.T) {
+	// Check for leaking routines
+	report := transportTest.CheckRoutines(t)
+	defer report()
+
+	type runResult struct {
+		dtlsConn *dtls.Conn
+		err      error
+	}
+
+	serverCert, err := selfsign.GenerateSelfSigned()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	clientCert, err := selfsign.GenerateSelfSigned()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, test := range []struct {
+		LossChanceRange int
+		DoClientAuth    bool
+		CipherSuites    []dtls.CipherSuiteID
+		MTU             int
+	}{
+		{
+			LossChanceRange: 0,
+		},
+		{
+			LossChanceRange: 10,
+		},
+		{
+			LossChanceRange: 20,
+		},
+		{
+			LossChanceRange: 50,
+		},
+		{
+			LossChanceRange: 0,
+			DoClientAuth:    true,
+		},
+		{
+			LossChanceRange: 10,
+			DoClientAuth:    true,
+		},
+		{
+			LossChanceRange: 20,
+			DoClientAuth:    true,
+		},
+		{
+			LossChanceRange: 50,
+			DoClientAuth:    true,
+		},
+		{
+			LossChanceRange: 0,
+			CipherSuites:    []dtls.CipherSuiteID{dtls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA},
+		},
+		{
+			LossChanceRange: 10,
+			CipherSuites:    []dtls.CipherSuiteID{dtls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA},
+		},
+		{
+			LossChanceRange: 20,
+			CipherSuites:    []dtls.CipherSuiteID{dtls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA},
+		},
+		{
+			LossChanceRange: 50,
+			CipherSuites:    []dtls.CipherSuiteID{dtls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA},
+		},
+		{
+			LossChanceRange: 10,
+			MTU:             100,
+			DoClientAuth:    true,
+		},
+		{
+			LossChanceRange: 20,
+			MTU:             100,
+			DoClientAuth:    true,
+		},
+		{
+			LossChanceRange: 50,
+			MTU:             100,
+			DoClientAuth:    true,
+		},
+	} {
+		name := fmt.Sprintf("Loss%d_MTU%d", test.LossChanceRange, test.MTU)
+		if test.DoClientAuth {
+			name += "_WithCliAuth"
+		}
+		for _, ciph := range test.CipherSuites {
+			name += "_With" + ciph.String()
+		}
+		test := test
+		t.Run(name, func(t *testing.T) {
+			// Limit runtime in case of deadlocks
+			lim := transportTest.TimeOut(lossyTestTimeout + time.Second)
+			defer lim.Stop()
+
+			rand.Seed(time.Now().UTC().UnixNano())
+			chosenLoss := rand.Intn(9) + test.LossChanceRange //nolint:gosec
+			serverDone := make(chan runResult)
+			clientDone := make(chan runResult)
+			br := transportTest.NewBridge()
+
+			if err = br.SetLossChance(chosenLoss); err != nil {
+				t.Fatal(err)
+			}
+
+			go func() {
+				cfg := &dtls.Config{
+					FlightInterval:     flightInterval,
+					CipherSuites:       test.CipherSuites,
+					InsecureSkipVerify: true,
+					MTU:                test.MTU,
+				}
+
+				if test.DoClientAuth {
+					cfg.Certificates = []tls.Certificate{clientCert}
+				}
+
+				client, startupErr := dtls.Client(br.GetConn0(), cfg)
+				clientDone <- runResult{client, startupErr}
+			}()
+
+			go func() {
+				cfg := &dtls.Config{
+					Certificates:   []tls.Certificate{serverCert},
+					FlightInterval: flightInterval,
+					MTU:            test.MTU,
+				}
+
+				if test.DoClientAuth {
+					cfg.ClientAuth = dtls.RequireAnyClientCert
+				}
+
+				server, startupErr := dtls.Server(br.GetConn1(), cfg)
+				serverDone <- runResult{server, startupErr}
+			}()
+
+			testTimer := time.NewTimer(lossyTestTimeout)
+			var serverConn, clientConn *dtls.Conn
+			defer func() {
+				if serverConn != nil {
+					if err = serverConn.Close(); err != nil {
+						t.Error(err)
+					}
+				}
+				if clientConn != nil {
+					if err = clientConn.Close(); err != nil {
+						t.Error(err)
+					}
+				}
+			}()
+
+			for {
+				if serverConn != nil && clientConn != nil {
+					break
+				}
+
+				br.Tick()
+				select {
+				case serverResult := <-serverDone:
+					if serverResult.err != nil {
+						t.Errorf("Fail, serverError: clientComplete(%t) serverComplete(%t) LossChance(%d) error(%v)", clientConn != nil, serverConn != nil, chosenLoss, serverResult.err)
+						return
+					}
+
+					serverConn = serverResult.dtlsConn
+				case clientResult := <-clientDone:
+					if clientResult.err != nil {
+						t.Errorf("Fail, clientError: clientComplete(%t) serverComplete(%t) LossChance(%d) error(%v)", clientConn != nil, serverConn != nil, chosenLoss, clientResult.err)
+						return
+					}
+
+					clientConn = clientResult.dtlsConn
+				case <-testTimer.C:
+					t.Errorf("Test expired: clientComplete(%t) serverComplete(%t) LossChance(%d)", clientConn != nil, serverConn != nil, chosenLoss)
+					return
+				case <-time.After(10 * time.Millisecond):
+				}
+			}
+		})
+	}
+}

dtls-2.0.9/e2e/e2e_openssl_test.go

@@ -0,0 +1,250 @@
+// +build openssl,!js
+
+package e2e
+
+import (
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2"
+)
+
+func serverOpenSSL(c *comm) {
+	go func() {
+		c.serverMutex.Lock()
+		defer c.serverMutex.Unlock()
+
+		cfg := c.serverConfig
+
+		// create openssl arguments
+		args := []string{
+			"s_server",
+			"-dtls1_2",
+			"-quiet",
+			"-verify_quiet",
+			"-verify_return_error",
+			fmt.Sprintf("-accept=%d", c.serverPort),
+		}
+		ciphers := ciphersOpenSSL(cfg)
+		if ciphers != "" {
+			args = append(args, fmt.Sprintf("-cipher=%s", ciphers))
+		}
+
+		// psk arguments
+		if cfg.PSK != nil {
+			psk, err := cfg.PSK(nil)
+			if err != nil {
+				c.errChan <- err
+				return
+			}
+			args = append(args, fmt.Sprintf("-psk=%X", psk))
+			if len(cfg.PSKIdentityHint) > 0 {
+				args = append(args, fmt.Sprintf("-psk_hint=%s", cfg.PSKIdentityHint))
+			}
+		}
+
+		// certs arguments
+		if len(cfg.Certificates) > 0 {
+			// create temporary cert files
+			certPEM, keyPEM, err := writeTempPEM(cfg)
+			if err != nil {
+				c.errChan <- err
+				return
+			}
+			args = append(args,
+				fmt.Sprintf("-cert=%s", certPEM),
+				fmt.Sprintf("-key=%s", keyPEM))
+			defer func() {
+				_ = os.Remove(certPEM)
+				_ = os.Remove(keyPEM)
+			}()
+		} else {
+			args = append(args, "-nocert")
+		}
+
+		// launch command
+		// #nosec G204
+		cmd := exec.CommandContext(c.ctx, "openssl", args...)
+		var inner net.Conn
+		inner, c.serverConn = net.Pipe()
+		cmd.Stdin = inner
+		cmd.Stdout = inner
+		cmd.Stderr = os.Stderr
+		if err := cmd.Start(); err != nil {
+			c.errChan <- err
+			_ = inner.Close()
+			return
+		}
+
+		// Ensure that server has started
+		time.Sleep(500 * time.Millisecond)
+
+		c.serverReady <- struct{}{}
+		simpleReadWrite(c.errChan, c.serverChan, c.serverConn, c.messageRecvCount)
+	}()
+}
+
+func clientOpenSSL(c *comm) {
+	select {
+	case <-c.serverReady:
+		// OK
+	case <-time.After(time.Second):
+		c.errChan <- errors.New("waiting on serverReady err: timeout")
+	}
+
+	c.clientMutex.Lock()
+	defer c.clientMutex.Unlock()
+
+	cfg := c.clientConfig
+
+	// create openssl arguments
+	args := []string{
+		"s_client",
+		"-dtls1_2",
+		"-quiet",
+		"-verify_quiet",
+		"-verify_return_error",
+		"-servername=localhost",
+		fmt.Sprintf("-connect=127.0.0.1:%d", c.serverPort),
+	}
+	ciphers := ciphersOpenSSL(cfg)
+	if ciphers != "" {
+		args = append(args, fmt.Sprintf("-cipher=%s", ciphers))
+	}
+
+	// psk arguments
+	if cfg.PSK != nil {
+		psk, err := cfg.PSK(nil)
+		if err != nil {
+			c.errChan <- err
+			return
+		}
+		args = append(args, fmt.Sprintf("-psk=%X", psk))
+	}
+
+	// certificate arguments
+	if len(cfg.Certificates) > 0 {
+		// create temporary cert files
+		certPEM, keyPEM, err := writeTempPEM(cfg)
+		if err != nil {
+			c.errChan <- err
+			return
+		}
+		args = append(args, fmt.Sprintf("-CAfile=%s", certPEM))
+		defer func() {
+			_ = os.Remove(certPEM)
+			_ = os.Remove(keyPEM)
+		}()
+	}
+
+	// launch command
+	// #nosec G204
+	cmd := exec.CommandContext(c.ctx, "openssl", args...)
+	var inner net.Conn
+	inner, c.clientConn = net.Pipe()
+	cmd.Stdin = inner
+	cmd.Stdout = inner
+	cmd.Stderr = os.Stderr
+	if err := cmd.Start(); err != nil {
+		c.errChan <- err
+		_ = inner.Close()
+		return
+	}
+
+	simpleReadWrite(c.errChan, c.clientChan, c.clientConn, c.messageRecvCount)
+}
+
+func ciphersOpenSSL(cfg *dtls.Config) string {
+	// See https://tls.mbed.org/supported-ssl-ciphersuites
+	translate := map[dtls.CipherSuiteID]string{
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_128_CCM:        "ECDHE-ECDSA-AES128-CCM",
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8:      "ECDHE-ECDSA-AES128-CCM8",
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256: "ECDHE-ECDSA-AES128-GCM-SHA256",
+		dtls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256:   "ECDHE-RSA-AES128-GCM-SHA256",
+
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA: "ECDHE-ECDSA-AES256-SHA",
+		dtls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA:   "ECDHE-RSA-AES128-SHA",
+
+		dtls.TLS_PSK_WITH_AES_128_CCM:        "PSK-AES128-CCM",
+		dtls.TLS_PSK_WITH_AES_128_CCM_8:      "PSK-AES128-CCM8",
+		dtls.TLS_PSK_WITH_AES_128_GCM_SHA256: "PSK-AES128-GCM-SHA256",
+	}
+
+	var ciphers []string
+	for _, c := range cfg.CipherSuites {
+		if text, ok := translate[c]; ok {
+			ciphers = append(ciphers, text)
+		}
+	}
+	return strings.Join(ciphers, ";")
+}
+
+func writeTempPEM(cfg *dtls.Config) (string, string, error) {
+	certOut, err := ioutil.TempFile("", "cert.pem")
+	if err != nil {
+		return "", "", fmt.Errorf("failed to create temporary file: %w", err)
+	}
+	keyOut, err := ioutil.TempFile("", "key.pem")
+	if err != nil {
+		return "", "", fmt.Errorf("failed to create temporary file: %w", err)
+	}
+
+	cert := cfg.Certificates[0]
+	derBytes := cert.Certificate[0]
+	if err = pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
+		return "", "", fmt.Errorf("failed to write data to cert.pem: %w", err)
+	}
+	if err = certOut.Close(); err != nil {
+		return "", "", fmt.Errorf("error closing cert.pem: %w", err)
+	}
+
+	priv := cert.PrivateKey
+	var privBytes []byte
+	privBytes, err = x509.MarshalPKCS8PrivateKey(priv)
+	if err != nil {
+		return "", "", fmt.Errorf("unable to marshal private key: %w", err)
+	}
+	if err = pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
+		return "", "", fmt.Errorf("failed to write data to key.pem: %w", err)
+	}
+	if err = keyOut.Close(); err != nil {
+		return "", "", fmt.Errorf("error closing key.pem: %w", err)
+	}
+	return certOut.Name(), keyOut.Name(), nil
+}
+
+func TestPionOpenSSLE2ESimple(t *testing.T) {
+	t.Run("OpenSSLServer", func(t *testing.T) {
+		testPionE2ESimple(t, serverOpenSSL, clientPion)
+	})
+	t.Run("OpenSSLClient", func(t *testing.T) {
+		testPionE2ESimple(t, serverPion, clientOpenSSL)
+	})
+}
+
+func TestPionOpenSSLE2ESimplePSK(t *testing.T) {
+	t.Run("OpenSSLServer", func(t *testing.T) {
+		testPionE2ESimplePSK(t, serverOpenSSL, clientPion)
+	})
+	t.Run("OpenSSLClient", func(t *testing.T) {
+		testPionE2ESimplePSK(t, serverPion, clientOpenSSL)
+	})
+}
+
+func TestPionOpenSSLE2EMTUs(t *testing.T) {
+	t.Run("OpenSSLServer", func(t *testing.T) {
+		testPionE2EMTUs(t, serverOpenSSL, clientPion)
+	})
+	t.Run("OpenSSLClient", func(t *testing.T) {
+		testPionE2EMTUs(t, serverPion, clientOpenSSL)
+	})
+}

dtls-2.0.9/e2e/e2e_openssl_v113_test.go

@@ -0,0 +1,17 @@
+// +build openssl,go1.13,!js
+
+package e2e
+
+import (
+	"testing"
+)
+
+func TestPionOpenSSLE2ESimpleED25519(t *testing.T) {
+	t.Skip("TODO: waiting OpenSSL's DTLS Ed25519 support")
+	t.Run("OpenSSLServer", func(t *testing.T) {
+		testPionE2ESimpleED25519(t, serverOpenSSL, clientPion)
+	})
+	t.Run("OpenSSLClient", func(t *testing.T) {
+		testPionE2ESimpleED25519(t, serverPion, clientOpenSSL)
+	})
+}

dtls-2.0.9/e2e/e2e_test.go

@@ -0,0 +1,329 @@
+// +build !js
+
+package e2e
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+	"github.com/pion/transport/test"
+)
+
+const (
+	testMessage   = "Hello World"
+	testTimeLimit = 5 * time.Second
+	messageRetry  = 200 * time.Millisecond
+)
+
+var errServerTimeout = errors.New("waiting on serverReady err: timeout")
+
+func randomPort(t testing.TB) int {
+	t.Helper()
+	conn, err := net.ListenPacket("udp4", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("failed to pickPort: %v", err)
+	}
+	defer func() {
+		_ = conn.Close()
+	}()
+	switch addr := conn.LocalAddr().(type) {
+	case *net.UDPAddr:
+		return addr.Port
+	default:
+		t.Fatalf("unknown addr type %T", addr)
+		return 0
+	}
+}
+
+func simpleReadWrite(errChan chan error, outChan chan string, conn io.ReadWriter, messageRecvCount *uint64) {
+	go func() {
+		buffer := make([]byte, 8192)
+		n, err := conn.Read(buffer)
+		if err != nil {
+			errChan <- err
+			return
+		}
+
+		outChan <- string(buffer[:n])
+		atomic.AddUint64(messageRecvCount, 1)
+	}()
+
+	for {
+		if atomic.LoadUint64(messageRecvCount) == 2 {
+			break
+		} else if _, err := conn.Write([]byte(testMessage)); err != nil {
+			errChan <- err
+			break
+		}
+
+		time.Sleep(messageRetry)
+	}
+}
+
+type comm struct {
+	ctx                        context.Context
+	clientConfig, serverConfig *dtls.Config
+	serverPort                 int
+	messageRecvCount           *uint64 // Counter to make sure both sides got a message
+	clientMutex                *sync.Mutex
+	clientConn                 net.Conn
+	serverMutex                *sync.Mutex
+	serverConn                 net.Conn
+	serverListener             net.Listener
+	serverReady                chan struct{}
+	errChan                    chan error
+	clientChan                 chan string
+	serverChan                 chan string
+	client                     func(*comm)
+	server                     func(*comm)
+}
+
+func newComm(ctx context.Context, clientConfig, serverConfig *dtls.Config, serverPort int, server, client func(*comm)) *comm {
+	messageRecvCount := uint64(0)
+	c := &comm{
+		ctx:              ctx,
+		clientConfig:     clientConfig,
+		serverConfig:     serverConfig,
+		serverPort:       serverPort,
+		messageRecvCount: &messageRecvCount,
+		clientMutex:      &sync.Mutex{},
+		serverMutex:      &sync.Mutex{},
+		serverReady:      make(chan struct{}),
+		errChan:          make(chan error),
+		clientChan:       make(chan string),
+		serverChan:       make(chan string),
+		server:           server,
+		client:           client,
+	}
+	return c
+}
+
+func (c *comm) assert(t *testing.T) {
+	// DTLS Client
+	go c.client(c)
+
+	// DTLS Server
+	go c.server(c)
+
+	defer func() {
+		if c.clientConn != nil {
+			if err := c.clientConn.Close(); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if c.serverConn != nil {
+			if err := c.serverConn.Close(); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if c.serverListener != nil {
+			if err := c.serverListener.Close(); err != nil {
+				t.Fatal(err)
+			}
+		}
+	}()
+
+	func() {
+		seenClient, seenServer := false, false
+		for {
+			select {
+			case err := <-c.errChan:
+				t.Fatal(err)
+			case <-time.After(testTimeLimit):
+				t.Fatalf("Test timeout, seenClient %t seenServer %t", seenClient, seenServer)
+			case clientMsg := <-c.clientChan:
+				if clientMsg != testMessage {
+					t.Fatalf("clientMsg does not equal test message: %s %s", clientMsg, testMessage)
+				}
+
+				seenClient = true
+				if seenClient && seenServer {
+					return
+				}
+			case serverMsg := <-c.serverChan:
+				if serverMsg != testMessage {
+					t.Fatalf("serverMsg does not equal test message: %s %s", serverMsg, testMessage)
+				}
+
+				seenServer = true
+				if seenClient && seenServer {
+					return
+				}
+			}
+		}
+	}()
+}
+
+func clientPion(c *comm) {
+	select {
+	case <-c.serverReady:
+		// OK
+	case <-time.After(time.Second):
+		c.errChan <- errServerTimeout
+	}
+
+	c.clientMutex.Lock()
+	defer c.clientMutex.Unlock()
+
+	var err error
+	c.clientConn, err = dtls.DialWithContext(c.ctx, "udp",
+		&net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: c.serverPort},
+		c.clientConfig,
+	)
+	if err != nil {
+		c.errChan <- err
+		return
+	}
+
+	simpleReadWrite(c.errChan, c.clientChan, c.clientConn, c.messageRecvCount)
+}
+
+func serverPion(c *comm) {
+	c.serverMutex.Lock()
+	defer c.serverMutex.Unlock()
+
+	var err error
+	c.serverListener, err = dtls.Listen("udp",
+		&net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: c.serverPort},
+		c.serverConfig,
+	)
+	if err != nil {
+		c.errChan <- err
+		return
+	}
+	c.serverReady <- struct{}{}
+	c.serverConn, err = c.serverListener.Accept()
+	if err != nil {
+		c.errChan <- err
+		return
+	}
+
+	simpleReadWrite(c.errChan, c.serverChan, c.serverConn, c.messageRecvCount)
+}
+
+/*
+  Simple DTLS Client/Server can communicate
+    - Assert that you can send messages both ways
+	- Assert that Close() on both ends work
+	- Assert that no Goroutines are leaked
+*/
+func testPionE2ESimple(t *testing.T, server, client func(*comm)) {
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	report := test.CheckRoutines(t)
+	defer report()
+
+	for _, cipherSuite := range []dtls.CipherSuiteID{
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+	} {
+		cipherSuite := cipherSuite
+		t.Run(cipherSuite.String(), func(t *testing.T) {
+			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			defer cancel()
+
+			cert, err := selfsign.GenerateSelfSignedWithDNS("localhost")
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			cfg := &dtls.Config{
+				Certificates:       []tls.Certificate{cert},
+				CipherSuites:       []dtls.CipherSuiteID{cipherSuite},
+				InsecureSkipVerify: true,
+			}
+			serverPort := randomPort(t)
+			comm := newComm(ctx, cfg, cfg, serverPort, server, client)
+			comm.assert(t)
+		})
+	}
+}
+
+func testPionE2ESimplePSK(t *testing.T, server, client func(*comm)) {
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	report := test.CheckRoutines(t)
+	defer report()
+
+	for _, cipherSuite := range []dtls.CipherSuiteID{
+		dtls.TLS_PSK_WITH_AES_128_CCM,
+		dtls.TLS_PSK_WITH_AES_128_CCM_8,
+		dtls.TLS_PSK_WITH_AES_128_GCM_SHA256,
+	} {
+		cipherSuite := cipherSuite
+		t.Run(cipherSuite.String(), func(t *testing.T) {
+			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			defer cancel()
+
+			cfg := &dtls.Config{
+				PSK: func(hint []byte) ([]byte, error) {
+					return []byte{0xAB, 0xC1, 0x23}, nil
+				},
+				PSKIdentityHint: []byte{0x01, 0x02, 0x03, 0x04, 0x05},
+				CipherSuites:    []dtls.CipherSuiteID{cipherSuite},
+			}
+			serverPort := randomPort(t)
+			comm := newComm(ctx, cfg, cfg, serverPort, server, client)
+			comm.assert(t)
+		})
+	}
+}
+
+func testPionE2EMTUs(t *testing.T, server, client func(*comm)) {
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	report := test.CheckRoutines(t)
+	defer report()
+
+	for _, mtu := range []int{
+		10000,
+		1000,
+		100,
+	} {
+		mtu := mtu
+		t.Run(fmt.Sprintf("MTU%d", mtu), func(t *testing.T) {
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancel()
+
+			cert, err := selfsign.GenerateSelfSignedWithDNS("localhost")
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			cfg := &dtls.Config{
+				Certificates:       []tls.Certificate{cert},
+				CipherSuites:       []dtls.CipherSuiteID{dtls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+				InsecureSkipVerify: true,
+				MTU:                mtu,
+			}
+			serverPort := randomPort(t)
+			comm := newComm(ctx, cfg, cfg, serverPort, server, client)
+			comm.assert(t)
+		})
+	}
+}
+
+func TestPionE2ESimple(t *testing.T) {
+	testPionE2ESimple(t, serverPion, clientPion)
+}
+
+func TestPionE2ESimplePSK(t *testing.T) {
+	testPionE2ESimplePSK(t, serverPion, clientPion)
+}
+
+func TestPionE2EMTUs(t *testing.T) {
+	testPionE2EMTUs(t, serverPion, clientPion)
+}

dtls-2.0.9/e2e/e2e_v113_test.go

@@ -0,0 +1,62 @@
+// +build go1.13,!js
+
+package e2e
+
+import (
+	"context"
+	"crypto/ed25519"
+	"crypto/rand"
+	"crypto/tls"
+	"testing"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+	"github.com/pion/transport/test"
+)
+
+// ED25519 is not supported in Go 1.12 crypto/x509.
+// Once Go 1.12 is deprecated, move this test to e2e_test.go.
+
+func testPionE2ESimpleED25519(t *testing.T, server, client func(*comm)) {
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	report := test.CheckRoutines(t)
+	defer report()
+
+	for _, cipherSuite := range []dtls.CipherSuiteID{
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_128_CCM,
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8,
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+		dtls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+	} {
+		cipherSuite := cipherSuite
+		t.Run(cipherSuite.String(), func(t *testing.T) {
+			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+			defer cancel()
+
+			_, key, err := ed25519.GenerateKey(rand.Reader)
+			if err != nil {
+				t.Fatal(err)
+			}
+			cert, err := selfsign.SelfSign(key)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			cfg := &dtls.Config{
+				Certificates:       []tls.Certificate{cert},
+				CipherSuites:       []dtls.CipherSuiteID{cipherSuite},
+				InsecureSkipVerify: true,
+			}
+			serverPort := randomPort(t)
+			comm := newComm(ctx, cfg, cfg, serverPort, server, client)
+			comm.assert(t)
+		})
+	}
+}
+
+func TestPionE2ESimpleED25519(t *testing.T) {
+	testPionE2ESimpleED25519(t, serverPion, clientPion)
+}

dtls-2.0.9/errors.go

@@ -0,0 +1,141 @@
+package dtls
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"golang.org/x/xerrors"
+)
+
+// Typed errors
+var (
+	ErrConnClosed = &FatalError{Err: errors.New("conn is closed")} //nolint:goerr113
+
+	errDeadlineExceeded   = &TimeoutError{Err: xerrors.Errorf("read/write timeout: %w", context.DeadlineExceeded)}
+	errInvalidContentType = &TemporaryError{Err: errors.New("invalid content type")} //nolint:goerr113
+
+	errBufferTooSmall               = &TemporaryError{Err: errors.New("buffer is too small")}                                        //nolint:goerr113
+	errContextUnsupported           = &TemporaryError{Err: errors.New("context is not supported for ExportKeyingMaterial")}          //nolint:goerr113
+	errHandshakeInProgress          = &TemporaryError{Err: errors.New("handshake is in progress")}                                   //nolint:goerr113
+	errReservedExportKeyingMaterial = &TemporaryError{Err: errors.New("ExportKeyingMaterial can not be used with a reserved label")} //nolint:goerr113
+	errApplicationDataEpochZero     = &TemporaryError{Err: errors.New("ApplicationData with epoch of 0")}                            //nolint:goerr113
+	errUnhandledContextType         = &TemporaryError{Err: errors.New("unhandled contentType")}                                      //nolint:goerr113
+
+	errCertificateVerifyNoCertificate    = &FatalError{Err: errors.New("client sent certificate verify but we have no certificate to verify")}                      //nolint:goerr113
+	errCipherSuiteNoIntersection         = &FatalError{Err: errors.New("client+server do not support any shared cipher suites")}                                    //nolint:goerr113
+	errClientCertificateNotVerified      = &FatalError{Err: errors.New("client sent certificate but did not verify it")}                                            //nolint:goerr113
+	errClientCertificateRequired         = &FatalError{Err: errors.New("server required client verification, but got none")}                                        //nolint:goerr113
+	errClientNoMatchingSRTPProfile       = &FatalError{Err: errors.New("server responded with SRTP Profile we do not support")}                                     //nolint:goerr113
+	errClientRequiredButNoServerEMS      = &FatalError{Err: errors.New("client required Extended Master Secret extension, but server does not support it")}         //nolint:goerr113
+	errCookieMismatch                    = &FatalError{Err: errors.New("client+server cookie does not match")}                                                      //nolint:goerr113
+	errIdentityNoPSK                     = &FatalError{Err: errors.New("PSK Identity Hint provided but PSK is nil")}                                                //nolint:goerr113
+	errInvalidCertificate                = &FatalError{Err: errors.New("no certificate provided")}                                                                  //nolint:goerr113
+	errInvalidCipherSuite                = &FatalError{Err: errors.New("invalid or unknown cipher suite")}                                                          //nolint:goerr113
+	errInvalidECDSASignature             = &FatalError{Err: errors.New("ECDSA signature contained zero or negative values")}                                        //nolint:goerr113
+	errInvalidPrivateKey                 = &FatalError{Err: errors.New("invalid private key type")}                                                                 //nolint:goerr113
+	errInvalidSignatureAlgorithm         = &FatalError{Err: errors.New("invalid signature algorithm")}                                                              //nolint:goerr113
+	errKeySignatureMismatch              = &FatalError{Err: errors.New("expected and actual key signature do not match")}                                           //nolint:goerr113
+	errNilNextConn                       = &FatalError{Err: errors.New("Conn can not be created with a nil nextConn")}                                              //nolint:goerr113
+	errNoAvailableCipherSuites           = &FatalError{Err: errors.New("connection can not be created, no CipherSuites satisfy this Config")}                       //nolint:goerr113
+	errNoAvailablePSKCipherSuite         = &FatalError{Err: errors.New("connection can not be created, pre-shared key present but no compatible CipherSuite")}      //nolint:goerr113
+	errNoAvailableCertificateCipherSuite = &FatalError{Err: errors.New("connection can not be created, certificate present but no compatible CipherSuite")}         //nolint:goerr113
+	errNoAvailableSignatureSchemes       = &FatalError{Err: errors.New("connection can not be created, no SignatureScheme satisfy this Config")}                    //nolint:goerr113
+	errNoCertificates                    = &FatalError{Err: errors.New("no certificates configured")}                                                               //nolint:goerr113
+	errNoConfigProvided                  = &FatalError{Err: errors.New("no config provided")}                                                                       //nolint:goerr113
+	errNoSupportedEllipticCurves         = &FatalError{Err: errors.New("client requested zero or more elliptic curves that are not supported by the server")}       //nolint:goerr113
+	errUnsupportedProtocolVersion        = &FatalError{Err: errors.New("unsupported protocol version")}                                                             //nolint:goerr113
+	errPSKAndIdentityMustBeSetForClient  = &FatalError{Err: errors.New("PSK and PSK Identity Hint must both be set for client")}                                    //nolint:goerr113
+	errRequestedButNoSRTPExtension       = &FatalError{Err: errors.New("SRTP support was requested but server did not respond with use_srtp extension")}            //nolint:goerr113
+	errServerNoMatchingSRTPProfile       = &FatalError{Err: errors.New("client requested SRTP but we have no matching profiles")}                                   //nolint:goerr113
+	errServerRequiredButNoClientEMS      = &FatalError{Err: errors.New("server requires the Extended Master Secret extension, but the client does not support it")} //nolint:goerr113
+	errVerifyDataMismatch                = &FatalError{Err: errors.New("expected and actual verify data does not match")}                                           //nolint:goerr113
+
+	errInvalidFlight                     = &InternalError{Err: errors.New("invalid flight number")}                           //nolint:goerr113
+	errKeySignatureGenerateUnimplemented = &InternalError{Err: errors.New("unable to generate key signature, unimplemented")} //nolint:goerr113
+	errKeySignatureVerifyUnimplemented   = &InternalError{Err: errors.New("unable to verify key signature, unimplemented")}   //nolint:goerr113
+	errLengthMismatch                    = &InternalError{Err: errors.New("data length and declared length do not match")}    //nolint:goerr113
+	errSequenceNumberOverflow            = &InternalError{Err: errors.New("sequence number overflow")}                        //nolint:goerr113
+	errInvalidFSMTransition              = &InternalError{Err: errors.New("invalid state machine transition")}                //nolint:goerr113
+)
+
+// FatalError indicates that the DTLS connection is no longer available.
+// It is mainly caused by wrong configuration of server or client.
+type FatalError = protocol.FatalError
+
+// InternalError indicates and internal error caused by the implementation, and the DTLS connection is no longer available.
+// It is mainly caused by bugs or tried to use unimplemented features.
+type InternalError = protocol.InternalError
+
+// TemporaryError indicates that the DTLS connection is still available, but the request was failed temporary.
+type TemporaryError = protocol.TemporaryError
+
+// TimeoutError indicates that the request was timed out.
+type TimeoutError = protocol.TimeoutError
+
+// HandshakeError indicates that the handshake failed.
+type HandshakeError = protocol.HandshakeError
+
+// invalidCipherSuite indicates an attempt at using an unsupported cipher suite.
+type invalidCipherSuite struct {
+	id CipherSuiteID
+}
+
+func (e *invalidCipherSuite) Error() string {
+	return fmt.Sprintf("CipherSuite with id(%d) is not valid", e.id)
+}
+
+func (e *invalidCipherSuite) Is(err error) bool {
+	if other, ok := err.(*invalidCipherSuite); ok {
+		return e.id == other.id
+	}
+	return false
+}
+
+// errAlert wraps DTLS alert notification as an error
+type errAlert struct {
+	*alert.Alert
+}
+
+func (e *errAlert) Error() string {
+	return fmt.Sprintf("alert: %s", e.Alert.String())
+}
+
+func (e *errAlert) IsFatalOrCloseNotify() bool {
+	return e.Level == alert.Fatal || e.Description == alert.CloseNotify
+}
+
+func (e *errAlert) Is(err error) bool {
+	if other, ok := err.(*errAlert); ok {
+		return e.Level == other.Level && e.Description == other.Description
+	}
+	return false
+}
+
+// netError translates an error from underlying Conn to corresponding net.Error.
+func netError(err error) error {
+	switch err {
+	case io.EOF, context.Canceled, context.DeadlineExceeded:
+		// Return io.EOF and context errors as is.
+		return err
+	}
+	switch e := err.(type) {
+	case (*net.OpError):
+		if se, ok := e.Err.(*os.SyscallError); ok {
+			if se.Timeout() {
+				return &TimeoutError{Err: err}
+			}
+			if isOpErrorTemporary(se) {
+				return &TemporaryError{Err: err}
+			}
+		}
+	case (net.Error):
+		return err
+	}
+	return &FatalError{Err: err}
+}

dtls-2.0.9/errors_errno.go

@@ -0,0 +1,25 @@
+// +build aix darwin dragonfly freebsd linux nacl nacljs netbsd openbsd solaris windows
+
+// For systems having syscall.Errno.
+// Update build targets by following command:
+// $ grep -R ECONN $(go env GOROOT)/src/syscall/zerrors_*.go \
+//     | tr "." "_" | cut -d"_" -f"2" | sort | uniq
+
+package dtls
+
+import (
+	"os"
+	"syscall"
+)
+
+func isOpErrorTemporary(err *os.SyscallError) bool {
+	if ne, ok := err.Err.(syscall.Errno); ok {
+		switch ne {
+		case syscall.ECONNREFUSED:
+			return true
+		default:
+			return false
+		}
+	}
+	return false
+}

dtls-2.0.9/errors_errno_test.go

@@ -0,0 +1,41 @@
+// +build aix darwin dragonfly freebsd linux nacl nacljs netbsd openbsd solaris windows
+
+// For systems having syscall.Errno.
+// The build target must be same as errors_errno.go.
+
+package dtls
+
+import (
+	"net"
+	"testing"
+)
+
+func TestErrorsTemporary(t *testing.T) {
+	addrListen, errListen := net.ResolveUDPAddr("udp", "localhost:0")
+	if errListen != nil {
+		t.Fatalf("Unexpected error: %v", errListen)
+	}
+	// Server is not listening.
+	conn, errDial := net.DialUDP("udp", nil, addrListen)
+	if errDial != nil {
+		t.Fatalf("Unexpected error: %v", errDial)
+	}
+
+	_, _ = conn.Write([]byte{0x00}) // trigger
+	_, err := conn.Read(make([]byte, 10))
+	_ = conn.Close()
+
+	if err == nil {
+		t.Skip("ECONNREFUSED is not set by system")
+	}
+	ne, ok := netError(err).(net.Error)
+	if !ok {
+		t.Fatalf("netError must return net.Error")
+	}
+	if ne.Timeout() {
+		t.Errorf("%v must not be timeout error", err)
+	}
+	if !ne.Temporary() {
+		t.Errorf("%v must be temporary error", err)
+	}
+}

dtls-2.0.9/errors_noerrno.go

@@ -0,0 +1,14 @@
+// +build !aix,!darwin,!dragonfly,!freebsd,!linux,!nacl,!nacljs,!netbsd,!openbsd,!solaris,!windows
+
+// For systems without syscall.Errno.
+// Build targets must be inverse of errors_errno.go
+
+package dtls
+
+import (
+	"os"
+)
+
+func isOpErrorTemporary(err *os.SyscallError) bool {
+	return false
+}

dtls-2.0.9/errors_test.go

@@ -0,0 +1,85 @@
+package dtls
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"testing"
+
+	"golang.org/x/xerrors"
+)
+
+var errExample = errors.New("an example error")
+
+func TestErrorUnwrap(t *testing.T) {
+	cases := []struct {
+		err          error
+		errUnwrapped []error
+	}{
+		{
+			&FatalError{Err: errExample},
+			[]error{errExample},
+		},
+		{
+			&TemporaryError{Err: errExample},
+			[]error{errExample},
+		},
+		{
+			&InternalError{Err: errExample},
+			[]error{errExample},
+		},
+		{
+			&TimeoutError{Err: errExample},
+			[]error{errExample},
+		},
+		{
+			&HandshakeError{Err: errExample},
+			[]error{errExample},
+		},
+	}
+	for _, c := range cases {
+		c := c
+		t.Run(fmt.Sprintf("%T", c.err), func(t *testing.T) {
+			err := c.err
+			for _, unwrapped := range c.errUnwrapped {
+				e := xerrors.Unwrap(err)
+				if !errors.Is(e, unwrapped) {
+					t.Errorf("Unwrapped error is expected to be '%v', got '%v'", unwrapped, e)
+				}
+			}
+		})
+	}
+}
+
+func TestErrorNetError(t *testing.T) {
+	cases := []struct {
+		err                error
+		str                string
+		timeout, temporary bool
+	}{
+		{&FatalError{Err: errExample}, "dtls fatal: an example error", false, false},
+		{&TemporaryError{Err: errExample}, "dtls temporary: an example error", false, true},
+		{&InternalError{Err: errExample}, "dtls internal: an example error", false, false},
+		{&TimeoutError{Err: errExample}, "dtls timeout: an example error", true, true},
+		{&HandshakeError{Err: errExample}, "handshake error: an example error", false, false},
+		{&HandshakeError{Err: &TimeoutError{Err: errExample}}, "handshake error: dtls timeout: an example error", true, true},
+	}
+	for _, c := range cases {
+		c := c
+		t.Run(fmt.Sprintf("%T", c.err), func(t *testing.T) {
+			ne, ok := c.err.(net.Error)
+			if !ok {
+				t.Fatalf("%T doesn't implement net.Error", c.err)
+			}
+			if ne.Timeout() != c.timeout {
+				t.Errorf("%T.Timeout() should be %v", c.err, c.timeout)
+			}
+			if ne.Temporary() != c.temporary {
+				t.Errorf("%T.Temporary() should be %v", c.err, c.temporary)
+			}
+			if ne.Error() != c.str {
+				t.Errorf("%T.Error() should be %v", c.err, c.str)
+			}
+		})
+	}
+}

dtls-2.0.9/examples/certificates/README.md

@@ -0,0 +1,26 @@
+# Certificates
+
+The certificates in for the examples are generated using the commands shown below.
+
+Note that this was run on OpenSSL 1.1.1d, of which the arguments can be found in the [OpenSSL Manpages](https://www.openssl.org/docs/man1.1.1/man1), and is not guaranteed to work on different OpenSSL versions.
+
+```shell
+# Extensions required for certificate validation.
+$ EXTFILE='extfile.conf'
+$ echo 'subjectAltName = IP:127.0.0.1\nbasicConstraints = critical,CA:true' > "${EXTFILE}"
+
+# Server.
+$ SERVER_NAME='server'
+$ openssl ecparam -name prime256v1 -genkey -noout -out "${SERVER_NAME}.pem"
+$ openssl req -key "${SERVER_NAME}.pem" -new -sha256 -subj '/C=NL' -out "${SERVER_NAME}.csr"
+$ openssl x509 -req -in "${SERVER_NAME}.csr" -extfile "${EXTFILE}" -days 365 -signkey "${SERVER_NAME}.pem" -sha256 -out "${SERVER_NAME}.pub.pem"
+
+# Client.
+$ CLIENT_NAME='client'
+$ openssl ecparam -name prime256v1 -genkey -noout -out "${CLIENT_NAME}.pem"
+$ openssl req -key "${CLIENT_NAME}.pem" -new -sha256 -subj '/C=NL' -out "${CLIENT_NAME}.csr"
+$ openssl x509 -req -in "${CLIENT_NAME}.csr" -extfile "${EXTFILE}" -days 365 -CA "${SERVER_NAME}.pub.pem" -CAkey "${SERVER_NAME}.pem" -set_serial '0xabcd' -sha256 -out "${CLIENT_NAME}.pub.pem"
+
+# Cleanup.
+$ rm "${EXTFILE}" "${SERVER_NAME}.csr" "${CLIENT_NAME}.csr"
+```

dtls-2.0.9/examples/certificates/client.pem

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIGOO78dEAcepxdUIeDzC28jMcFrJr2q7x+UdhgtJ/RS3oAoGCCqGSM49
+AwEHoUQDQgAEGLSNxlkJ9mETKI2Hogq3Cyh06pJKA1YMgcKqYKS6yQQlvvk5rU88
++RojFPgXJukymhfIJmw4eGxxEMSjuEZY7w==
+-----END EC PRIVATE KEY-----

dtls-2.0.9/examples/certificates/client.pub.pem

@@ -0,0 +1,9 @@
+-----BEGIN CERTIFICATE-----
+MIIBLTCB1aADAgECAgMAq80wCgYIKoZIzj0EAwIwDTELMAkGA1UEBhMCTkwwHhcN
+MjAwMzIwMDk0NjQ0WhcNMjEwMzIwMDk0NjQ0WjANMQswCQYDVQQGEwJOTDBZMBMG
+ByqGSM49AgEGCCqGSM49AwEHA0IABBi0jcZZCfZhEyiNh6IKtwsodOqSSgNWDIHC
+qmCkuskEJb75Oa1PPPkaIxT4FybpMpoXyCZsOHhscRDEo7hGWO+jJDAiMA8GA1Ud
+EQQIMAaHBH8AAAEwDwYDVR0TAQH/BAUwAwEB/zAKBggqhkjOPQQDAgNHADBEAiBx
+sIkcADN9E60veZOFOeANaRWAiQaLWZfUxqkOmfHztQIgI2CfHMjDQwJZFh35HvFs
+NOPJj8wxFhqR5pqMF23cgOY=
+-----END CERTIFICATE-----

dtls-2.0.9/examples/certificates/server.pem

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIDT8Xyx5RpPP+98ulYZKsvKIVdBUJug/L9H2M8JThv+GoAoGCCqGSM49
+AwEHoUQDQgAE6Wf0qQqIb5G7g51P83Dh1Yst52kyntGYz1Bt6S7crpmQFs9ZRZMy
+bJ6MGIwGcVBMgoL3pfxDKdZ3mnzmoibU0w==
+-----END EC PRIVATE KEY-----

dtls-2.0.9/examples/certificates/server.pub.pem

@@ -0,0 +1,9 @@
+-----BEGIN CERTIFICATE-----
+MIIBPzCB5qADAgECAhRtzyVTL+9D0KHfbcKYeKckpLVRmTAKBggqhkjOPQQDAjAN
+MQswCQYDVQQGEwJOTDAeFw0yMDAzMjAwOTQ2NDRaFw0yMTAzMjAwOTQ2NDRaMA0x
+CzAJBgNVBAYTAk5MMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE6Wf0qQqIb5G7
+g51P83Dh1Yst52kyntGYz1Bt6S7crpmQFs9ZRZMybJ6MGIwGcVBMgoL3pfxDKdZ3
+mnzmoibU06MkMCIwDwYDVR0RBAgwBocEfwAAATAPBgNVHRMBAf8EBTADAQH/MAoG
+CCqGSM49BAMCA0gAMEUCIQD000SU+klkNLGvHZcMYNVkCFsImnGKIqPMy3LELSiF
+0gIgSGIFkNEIAyNxn44CXZJu3piyz1ouK2fLefDJMYfcXgM=
+-----END CERTIFICATE-----

dtls-2.0.9/examples/dial/psk/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/examples/util"
+)
+
+func main() {
+	// Prepare the IP to connect to
+	addr := &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: 4444}
+
+	//
+	// Everything below is the pion-DTLS API! Thanks for using it ❤️.
+	//
+
+	// Prepare the configuration of the DTLS connection
+	config := &dtls.Config{
+		PSK: func(hint []byte) ([]byte, error) {
+			fmt.Printf("Server's hint: %s \n", hint)
+			return []byte{0xAB, 0xC1, 0x23}, nil
+		},
+		PSKIdentityHint:      []byte("Pion DTLS Server"),
+		CipherSuites:         []dtls.CipherSuiteID{dtls.TLS_PSK_WITH_AES_128_CCM_8},
+		ExtendedMasterSecret: dtls.RequireExtendedMasterSecret,
+	}
+
+	// Connect to a DTLS server
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	dtlsConn, err := dtls.DialWithContext(ctx, "udp", addr, config)
+	util.Check(err)
+	defer func() {
+		util.Check(dtlsConn.Close())
+	}()
+
+	fmt.Println("Connected; type 'exit' to shutdown gracefully")
+
+	// Simulate a chat session
+	util.Chat(dtlsConn)
+}

dtls-2.0.9/examples/dial/selfsign/main.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/examples/util"
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+)
+
+func main() {
+	// Prepare the IP to connect to
+	addr := &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: 4444}
+
+	// Generate a certificate and private key to secure the connection
+	certificate, genErr := selfsign.GenerateSelfSigned()
+	util.Check(genErr)
+
+	//
+	// Everything below is the pion-DTLS API! Thanks for using it ❤️.
+	//
+
+	// Prepare the configuration of the DTLS connection
+	config := &dtls.Config{
+		Certificates:         []tls.Certificate{certificate},
+		InsecureSkipVerify:   true,
+		ExtendedMasterSecret: dtls.RequireExtendedMasterSecret,
+	}
+
+	// Connect to a DTLS server
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	dtlsConn, err := dtls.DialWithContext(ctx, "udp", addr, config)
+	util.Check(err)
+	defer func() {
+		util.Check(dtlsConn.Close())
+	}()
+
+	fmt.Println("Connected; type 'exit' to shutdown gracefully")
+
+	// Simulate a chat session
+	util.Chat(dtlsConn)
+}

dtls-2.0.9/examples/dial/verify/main.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/examples/util"
+)
+
+func main() {
+	// Prepare the IP to connect to
+	addr := &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: 4444}
+
+	//
+	// Everything below is the pion-DTLS API! Thanks for using it ❤️.
+	//
+
+	certificate, err := util.LoadKeyAndCertificate("examples/certificates/client.pem",
+		"examples/certificates/client.pub.pem")
+	util.Check(err)
+
+	rootCertificate, err := util.LoadCertificate("examples/certificates/server.pub.pem")
+	util.Check(err)
+	certPool := x509.NewCertPool()
+	cert, err := x509.ParseCertificate(rootCertificate.Certificate[0])
+	util.Check(err)
+	certPool.AddCert(cert)
+
+	// Prepare the configuration of the DTLS connection
+	config := &dtls.Config{
+		Certificates:         []tls.Certificate{*certificate},
+		ExtendedMasterSecret: dtls.RequireExtendedMasterSecret,
+		RootCAs:              certPool,
+	}
+
+	// Connect to a DTLS server
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	dtlsConn, err := dtls.DialWithContext(ctx, "udp", addr, config)
+	util.Check(err)
+	defer func() {
+		util.Check(dtlsConn.Close())
+	}()
+
+	fmt.Println("Connected; type 'exit' to shutdown gracefully")
+
+	// Simulate a chat session
+	util.Chat(dtlsConn)
+}

dtls-2.0.9/examples/listen/psk/main.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/examples/util"
+)
+
+func main() {
+	// Prepare the IP to connect to
+	addr := &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: 4444}
+
+	// Create parent context to cleanup handshaking connections on exit.
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	//
+	// Everything below is the pion-DTLS API! Thanks for using it ❤️.
+	//
+
+	// Prepare the configuration of the DTLS connection
+	config := &dtls.Config{
+		PSK: func(hint []byte) ([]byte, error) {
+			fmt.Printf("Client's hint: %s \n", hint)
+			return []byte{0xAB, 0xC1, 0x23}, nil
+		},
+		PSKIdentityHint:      []byte("Pion DTLS Client"),
+		CipherSuites:         []dtls.CipherSuiteID{dtls.TLS_PSK_WITH_AES_128_CCM_8},
+		ExtendedMasterSecret: dtls.RequireExtendedMasterSecret,
+		// Create timeout context for accepted connection.
+		ConnectContextMaker: func() (context.Context, func()) {
+			return context.WithTimeout(ctx, 30*time.Second)
+		},
+	}
+
+	// Connect to a DTLS server
+	listener, err := dtls.Listen("udp", addr, config)
+	util.Check(err)
+	defer func() {
+		util.Check(listener.Close())
+	}()
+
+	fmt.Println("Listening")
+
+	// Simulate a chat session
+	hub := util.NewHub()
+
+	go func() {
+		for {
+			// Wait for a connection.
+			conn, err := listener.Accept()
+			util.Check(err)
+			// defer conn.Close() // TODO: graceful shutdown
+
+			// `conn` is of type `net.Conn` but may be casted to `dtls.Conn`
+			// using `dtlsConn := conn.(*dtls.Conn)` in order to to expose
+			// functions like `ConnectionState` etc.
+
+			// Register the connection with the chat hub
+			if err == nil {
+				hub.Register(conn)
+			}
+		}
+	}()
+
+	// Start chatting
+	hub.Chat()
+}

dtls-2.0.9/examples/listen/selfsign/main.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/examples/util"
+	"github.com/pion/dtls/v2/pkg/crypto/selfsign"
+)
+
+func main() {
+	// Prepare the IP to connect to
+	addr := &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: 4444}
+
+	// Generate a certificate and private key to secure the connection
+	certificate, genErr := selfsign.GenerateSelfSigned()
+	util.Check(genErr)
+
+	// Create parent context to cleanup handshaking connections on exit.
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	//
+	// Everything below is the pion-DTLS API! Thanks for using it ❤️.
+	//
+
+	// Prepare the configuration of the DTLS connection
+	config := &dtls.Config{
+		Certificates:         []tls.Certificate{certificate},
+		ExtendedMasterSecret: dtls.RequireExtendedMasterSecret,
+		// Create timeout context for accepted connection.
+		ConnectContextMaker: func() (context.Context, func()) {
+			return context.WithTimeout(ctx, 30*time.Second)
+		},
+	}
+
+	// Connect to a DTLS server
+	listener, err := dtls.Listen("udp", addr, config)
+	util.Check(err)
+	defer func() {
+		util.Check(listener.Close())
+	}()
+
+	fmt.Println("Listening")
+
+	// Simulate a chat session
+	hub := util.NewHub()
+
+	go func() {
+		for {
+			// Wait for a connection.
+			conn, err := listener.Accept()
+			util.Check(err)
+			// defer conn.Close() // TODO: graceful shutdown
+
+			// `conn` is of type `net.Conn` but may be casted to `dtls.Conn`
+			// using `dtlsConn := conn.(*dtls.Conn)` in order to to expose
+			// functions like `ConnectionState` etc.
+
+			// Register the connection with the chat hub
+			if err == nil {
+				hub.Register(conn)
+			}
+		}
+	}()
+
+	// Start chatting
+	hub.Chat()
+}

dtls-2.0.9/examples/listen/verify/main.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/pion/dtls/v2"
+	"github.com/pion/dtls/v2/examples/util"
+)
+
+func main() {
+	// Prepare the IP to connect to
+	addr := &net.UDPAddr{IP: net.ParseIP("127.0.0.1"), Port: 4444}
+
+	// Create parent context to cleanup handshaking connections on exit.
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	//
+	// Everything below is the pion-DTLS API! Thanks for using it ❤️.
+	//
+
+	certificate, err := util.LoadKeyAndCertificate("examples/certificates/server.pem",
+		"examples/certificates/server.pub.pem")
+	util.Check(err)
+
+	rootCertificate, err := util.LoadCertificate("examples/certificates/server.pub.pem")
+	util.Check(err)
+	certPool := x509.NewCertPool()
+	cert, err := x509.ParseCertificate(rootCertificate.Certificate[0])
+	util.Check(err)
+	certPool.AddCert(cert)
+
+	// Prepare the configuration of the DTLS connection
+	config := &dtls.Config{
+		Certificates:         []tls.Certificate{*certificate},
+		ExtendedMasterSecret: dtls.RequireExtendedMasterSecret,
+		ClientAuth:           dtls.RequireAndVerifyClientCert,
+		ClientCAs:            certPool,
+		// Create timeout context for accepted connection.
+		ConnectContextMaker: func() (context.Context, func()) {
+			return context.WithTimeout(ctx, 30*time.Second)
+		},
+	}
+
+	// Connect to a DTLS server
+	listener, err := dtls.Listen("udp", addr, config)
+	util.Check(err)
+	defer func() {
+		util.Check(listener.Close())
+	}()
+
+	fmt.Println("Listening")
+
+	// Simulate a chat session
+	hub := util.NewHub()
+
+	go func() {
+		for {
+			// Wait for a connection.
+			conn, err := listener.Accept()
+			util.Check(err)
+			// defer conn.Close() // TODO: graceful shutdown
+
+			// `conn` is of type `net.Conn` but may be casted to `dtls.Conn`
+			// using `dtlsConn := conn.(*dtls.Conn)` in order to to expose
+			// functions like `ConnectionState` etc.
+
+			// Register the connection with the chat hub
+			hub.Register(conn)
+		}
+	}()
+
+	// Start chatting
+	hub.Chat()
+}

dtls-2.0.9/examples/util/hub.go

@@ -0,0 +1,80 @@
+package util
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"os"
+	"strings"
+	"sync"
+)
+
+// Hub is a helper to handle one to many chat
+type Hub struct {
+	conns map[string]net.Conn
+	lock  sync.RWMutex
+}
+
+// NewHub builds a new hub
+func NewHub() *Hub {
+	return &Hub{conns: make(map[string]net.Conn)}
+}
+
+// Register adds a new conn to the Hub
+func (h *Hub) Register(conn net.Conn) {
+	fmt.Printf("Connected to %s\n", conn.RemoteAddr())
+	h.lock.Lock()
+	defer h.lock.Unlock()
+
+	h.conns[conn.RemoteAddr().String()] = conn
+
+	go h.readLoop(conn)
+}
+
+func (h *Hub) readLoop(conn net.Conn) {
+	b := make([]byte, bufSize)
+	for {
+		n, err := conn.Read(b)
+		if err != nil {
+			h.unregister(conn)
+			return
+		}
+		fmt.Printf("Got message: %s\n", string(b[:n]))
+	}
+}
+
+func (h *Hub) unregister(conn net.Conn) {
+	h.lock.Lock()
+	defer h.lock.Unlock()
+	delete(h.conns, conn.RemoteAddr().String())
+	err := conn.Close()
+	if err != nil {
+		fmt.Println("Failed to disconnect", conn.RemoteAddr(), err)
+	} else {
+		fmt.Println("Disconnected ", conn.RemoteAddr())
+	}
+}
+
+func (h *Hub) broadcast(msg []byte) {
+	h.lock.RLock()
+	defer h.lock.RUnlock()
+	for _, conn := range h.conns {
+		_, err := conn.Write(msg)
+		if err != nil {
+			fmt.Printf("Failed to write message to %s: %v\n", conn.RemoteAddr(), err)
+		}
+	}
+}
+
+// Chat starts the stdin readloop to dispatch messages to the hub
+func (h *Hub) Chat() {
+	reader := bufio.NewReader(os.Stdin)
+	for {
+		msg, err := reader.ReadString('\n')
+		Check(err)
+		if strings.TrimSpace(msg) == "exit" {
+			return
+		}
+		h.broadcast([]byte(msg))
+	}
+}

dtls-2.0.9/examples/util/util.go

@@ -0,0 +1,154 @@
+// Package util provides auxiliary utilities used in examples
+package util
+
+import (
+	"bufio"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const bufSize = 8192
+
+var (
+	errBlockIsNotPrivateKey  = errors.New("block is not a private key, unable to load key")
+	errUnknownKeyTime        = errors.New("unknown key time in PKCS#8 wrapping, unable to load key")
+	errNoPrivateKeyFound     = errors.New("no private key found, unable to load key")
+	errBlockIsNotCertificate = errors.New("block is not a certificate, unable to load certificates")
+	errNoCertificateFound    = errors.New("no certificate found, unable to load certificates")
+)
+
+// Chat simulates a simple text chat session over the connection
+func Chat(conn io.ReadWriter) {
+	go func() {
+		b := make([]byte, bufSize)
+
+		for {
+			n, err := conn.Read(b)
+			Check(err)
+			fmt.Printf("Got message: %s\n", string(b[:n]))
+		}
+	}()
+
+	reader := bufio.NewReader(os.Stdin)
+
+	for {
+		text, err := reader.ReadString('\n')
+		Check(err)
+
+		if strings.TrimSpace(text) == "exit" {
+			return
+		}
+
+		_, err = conn.Write([]byte(text))
+		Check(err)
+	}
+}
+
+// Check is a helper to throw errors in the examples
+func Check(err error) {
+	switch e := err.(type) {
+	case nil:
+	case (net.Error):
+		if e.Temporary() {
+			fmt.Printf("Warning: %v\n", err)
+			return
+		}
+
+		fmt.Printf("net.Error: %v\n", err)
+		panic(err)
+	default:
+		fmt.Printf("error: %v\n", err)
+		panic(err)
+	}
+}
+
+// LoadKeyAndCertificate reads certificates or key from file
+func LoadKeyAndCertificate(keyPath string, certificatePath string) (*tls.Certificate, error) {
+	privateKey, err := LoadKey(keyPath)
+	if err != nil {
+		return nil, err
+	}
+
+	certificate, err := LoadCertificate(certificatePath)
+	if err != nil {
+		return nil, err
+	}
+
+	certificate.PrivateKey = privateKey
+
+	return certificate, nil
+}
+
+// LoadKey Load/read key from file
+func LoadKey(path string) (crypto.PrivateKey, error) {
+	rawData, err := ioutil.ReadFile(filepath.Clean(path))
+	if err != nil {
+		return nil, err
+	}
+
+	block, _ := pem.Decode(rawData)
+	if block == nil || !strings.HasSuffix(block.Type, "PRIVATE KEY") {
+		return nil, errBlockIsNotPrivateKey
+	}
+
+	if key, err := x509.ParsePKCS1PrivateKey(block.Bytes); err == nil {
+		return key, nil
+	}
+
+	if key, err := x509.ParsePKCS8PrivateKey(block.Bytes); err == nil {
+		switch key := key.(type) {
+		case *rsa.PrivateKey, *ecdsa.PrivateKey:
+			return key, nil
+		default:
+			return nil, errUnknownKeyTime
+		}
+	}
+
+	if key, err := x509.ParseECPrivateKey(block.Bytes); err == nil {
+		return key, nil
+	}
+
+	return nil, errNoPrivateKeyFound
+}
+
+// LoadCertificate Load/read certificate(s) from file
+func LoadCertificate(path string) (*tls.Certificate, error) {
+	rawData, err := ioutil.ReadFile(filepath.Clean(path))
+	if err != nil {
+		return nil, err
+	}
+
+	var certificate tls.Certificate
+
+	for {
+		block, rest := pem.Decode(rawData)
+		if block == nil {
+			break
+		}
+
+		if block.Type != "CERTIFICATE" {
+			return nil, errBlockIsNotCertificate
+		}
+
+		certificate.Certificate = append(certificate.Certificate, block.Bytes)
+		rawData = rest
+	}
+
+	if len(certificate.Certificate) == 0 {
+		return nil, errNoCertificateFound
+	}
+
+	return &certificate, nil
+}

dtls-2.0.9/flight.go

@@ -0,0 +1,75 @@
+package dtls
+
+/*
+  DTLS messages are grouped into a series of message flights, according
+  to the diagrams below.  Although each flight of messages may consist
+  of a number of messages, they should be viewed as monolithic for the
+  purpose of timeout and retransmission.
+  https://tools.ietf.org/html/rfc4347#section-4.2.4
+  Client                                          Server
+  ------                                          ------
+                                      Waiting                 Flight 0
+
+  ClientHello             -------->                           Flight 1
+
+                          <-------    HelloVerifyRequest      Flight 2
+
+  ClientHello              -------->                           Flight 3
+
+                                             ServerHello    \
+                                            Certificate*     \
+                                      ServerKeyExchange*      Flight 4
+                                     CertificateRequest*     /
+                          <--------      ServerHelloDone    /
+
+  Certificate*                                              \
+  ClientKeyExchange                                          \
+  CertificateVerify*                                          Flight 5
+  [ChangeCipherSpec]                                         /
+  Finished                -------->                         /
+
+                                      [ChangeCipherSpec]    \ Flight 6
+                          <--------             Finished    /
+
+*/
+
+type flightVal uint8
+
+const (
+	flight0 flightVal = iota + 1
+	flight1
+	flight2
+	flight3
+	flight4
+	flight5
+	flight6
+)
+
+func (f flightVal) String() string {
+	switch f {
+	case flight0:
+		return "Flight 0"
+	case flight1:
+		return "Flight 1"
+	case flight2:
+		return "Flight 2"
+	case flight3:
+		return "Flight 3"
+	case flight4:
+		return "Flight 4"
+	case flight5:
+		return "Flight 5"
+	case flight6:
+		return "Flight 6"
+	default:
+		return "Invalid Flight"
+	}
+}
+
+func (f flightVal) isLastSendFlight() bool {
+	return f == flight6
+}
+
+func (f flightVal) isLastRecvFlight() bool {
+	return f == flight5
+}

dtls-2.0.9/flight0handler.go

@@ -0,0 +1,102 @@
+package dtls
+
+import (
+	"context"
+	"crypto/rand"
+
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/extension"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+)
+
+func flight0Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
+	seq, msgs, ok := cache.fullPullMap(0,
+		handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+	)
+	if !ok {
+		// No valid message received. Keep reading
+		return 0, nil, nil
+	}
+	state.handshakeRecvSequence = seq
+
+	var clientHello *handshake.MessageClientHello
+
+	// Validate type
+	if clientHello, ok = msgs[handshake.TypeClientHello].(*handshake.MessageClientHello); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+	}
+
+	if !clientHello.Version.Equal(protocol.Version1_2) {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
+	}
+
+	state.remoteRandom = clientHello.Random
+
+	cipherSuites := []CipherSuite{}
+	for _, id := range clientHello.CipherSuiteIDs {
+		if c := cipherSuiteForID(CipherSuiteID(id), cfg.customCipherSuites); c != nil {
+			cipherSuites = append(cipherSuites, c)
+		}
+	}
+
+	if state.cipherSuite, ok = findMatchingCipherSuite(cipherSuites, cfg.localCipherSuites); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errCipherSuiteNoIntersection
+	}
+
+	for _, val := range clientHello.Extensions {
+		switch e := val.(type) {
+		case *extension.SupportedEllipticCurves:
+			if len(e.EllipticCurves) == 0 {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errNoSupportedEllipticCurves
+			}
+			state.namedCurve = e.EllipticCurves[0]
+		case *extension.UseSRTP:
+			profile, ok := findMatchingSRTPProfile(e.ProtectionProfiles, cfg.localSRTPProtectionProfiles)
+			if !ok {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errServerNoMatchingSRTPProfile
+			}
+			state.srtpProtectionProfile = profile
+		case *extension.UseExtendedMasterSecret:
+			if cfg.extendedMasterSecret != DisableExtendedMasterSecret {
+				state.extendedMasterSecret = true
+			}
+		case *extension.ServerName:
+			state.serverName = e.ServerName // remote server name
+		}
+	}
+
+	if cfg.extendedMasterSecret == RequireExtendedMasterSecret && !state.extendedMasterSecret {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errServerRequiredButNoClientEMS
+	}
+
+	if state.localKeypair == nil {
+		var err error
+		state.localKeypair, err = elliptic.GenerateKeypair(state.namedCurve)
+		if err != nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, err
+		}
+	}
+
+	return flight2, nil, nil
+}
+
+func flight0Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
+	// Initialize
+	state.cookie = make([]byte, cookieLength)
+	if _, err := rand.Read(state.cookie); err != nil {
+		return nil, nil, err
+	}
+
+	var zeroEpoch uint16
+	state.localEpoch.Store(zeroEpoch)
+	state.remoteEpoch.Store(zeroEpoch)
+	state.namedCurve = defaultNamedCurve
+
+	if err := state.localRandom.Populate(); err != nil {
+		return nil, nil, err
+	}
+
+	return nil, nil, nil
+}

dtls-2.0.9/flight1handler.go

@@ -0,0 +1,112 @@
+package dtls
+
+import (
+	"context"
+
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/extension"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+func flight1Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
+	// HelloVerifyRequest can be skipped by the server,
+	// so allow ServerHello during flight1 also
+	seq, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
+		handshakeCachePullRule{handshake.TypeHelloVerifyRequest, cfg.initialEpoch, false, true},
+		handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, true},
+	)
+	if !ok {
+		// No valid message received. Keep reading
+		return 0, nil, nil
+	}
+
+	if _, ok := msgs[handshake.TypeServerHello]; ok {
+		// Flight1 and flight2 were skipped.
+		// Parse as flight3.
+		return flight3Parse(ctx, c, state, cache, cfg)
+	}
+
+	if h, ok := msgs[handshake.TypeHelloVerifyRequest].(*handshake.MessageHelloVerifyRequest); ok {
+		// DTLS 1.2 clients must not assume that the server will use the protocol version
+		// specified in HelloVerifyRequest message. RFC 6347 Section 4.2.1
+		if !h.Version.Equal(protocol.Version1_0) && !h.Version.Equal(protocol.Version1_2) {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
+		}
+		state.cookie = append([]byte{}, h.Cookie...)
+		state.handshakeRecvSequence = seq
+		return flight3, nil, nil
+	}
+
+	return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+}
+
+func flight1Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
+	var zeroEpoch uint16
+	state.localEpoch.Store(zeroEpoch)
+	state.remoteEpoch.Store(zeroEpoch)
+	state.namedCurve = defaultNamedCurve
+	state.cookie = nil
+
+	if err := state.localRandom.Populate(); err != nil {
+		return nil, nil, err
+	}
+
+	extensions := []extension.Extension{
+		&extension.SupportedSignatureAlgorithms{
+			SignatureHashAlgorithms: cfg.localSignatureSchemes,
+		},
+		&extension.RenegotiationInfo{
+			RenegotiatedConnection: 0,
+		},
+	}
+	if cfg.localPSKCallback == nil {
+		extensions = append(extensions, []extension.Extension{
+			&extension.SupportedEllipticCurves{
+				EllipticCurves: []elliptic.Curve{elliptic.X25519, elliptic.P256, elliptic.P384},
+			},
+			&extension.SupportedPointFormats{
+				PointFormats: []elliptic.CurvePointFormat{elliptic.CurvePointFormatUncompressed},
+			},
+		}...)
+	}
+
+	if len(cfg.localSRTPProtectionProfiles) > 0 {
+		extensions = append(extensions, &extension.UseSRTP{
+			ProtectionProfiles: cfg.localSRTPProtectionProfiles,
+		})
+	}
+
+	if cfg.extendedMasterSecret == RequestExtendedMasterSecret ||
+		cfg.extendedMasterSecret == RequireExtendedMasterSecret {
+		extensions = append(extensions, &extension.UseExtendedMasterSecret{
+			Supported: true,
+		})
+	}
+
+	if len(cfg.serverName) > 0 {
+		extensions = append(extensions, &extension.ServerName{ServerName: cfg.serverName})
+	}
+
+	return []*packet{
+		{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageClientHello{
+						Version:            protocol.Version1_2,
+						Cookie:             state.cookie,
+						Random:             state.localRandom,
+						CipherSuiteIDs:     cipherSuiteIDs(cfg.localCipherSuites),
+						CompressionMethods: defaultCompressionMethods(),
+						Extensions:         extensions,
+					},
+				},
+			},
+		},
+	}, nil, nil
+}

dtls-2.0.9/flight2handler.go

@@ -0,0 +1,78 @@
+package dtls
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+func flight2Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
+	seq, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
+		handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+	)
+	if !ok {
+		// Client may retransmit the first ClientHello when HelloVerifyRequest is dropped.
+		// Parse as flight 0 in this case.
+		return flight0Parse(ctx, c, state, cache, cfg)
+	}
+	state.handshakeRecvSequence = seq
+
+	var clientHello *handshake.MessageClientHello
+
+	// Validate type
+	if clientHello, ok = msgs[handshake.TypeClientHello].(*handshake.MessageClientHello); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+	}
+
+	if !clientHello.Version.Equal(protocol.Version1_2) {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
+	}
+
+	if len(clientHello.Cookie) == 0 {
+		return 0, nil, nil
+	}
+	if !bytes.Equal(state.cookie, clientHello.Cookie) {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.AccessDenied}, errCookieMismatch
+	}
+
+	// TODO 添加 CiscoCompat 支持
+	if cfg.localCiscoCompatCallback != nil {
+		var err error
+		state.SessionID = clientHello.SessionID
+		if len(state.SessionID) == 0 {
+			err = fmt.Errorf("clientHello SessionID is nil")
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, err
+		}
+
+		state.masterSecret, err = cfg.localCiscoCompatCallback(state.SessionID)
+		if err != nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, err
+		}
+	}
+
+	return flight4, nil, nil
+}
+
+func flight2Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
+	state.handshakeSendSequence = 0
+	return []*packet{
+		{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageHelloVerifyRequest{
+						Version: protocol.Version1_2,
+						Cookie:  state.cookie,
+					},
+				},
+			},
+		},
+	}, nil, nil
+}

dtls-2.0.9/flight3handler.go

@@ -0,0 +1,194 @@
+package dtls
+
+import (
+	"context"
+
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/crypto/prf"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/extension"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+func flight3Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) { //nolint:gocognit
+	// Clients may receive multiple HelloVerifyRequest messages with different cookies.
+	// Clients SHOULD handle this by sending a new ClientHello with a cookie in response
+	// to the new HelloVerifyRequest. RFC 6347 Section 4.2.1
+	seq, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
+		handshakeCachePullRule{handshake.TypeHelloVerifyRequest, cfg.initialEpoch, false, true},
+	)
+	if ok {
+		if h, msgOk := msgs[handshake.TypeHelloVerifyRequest].(*handshake.MessageHelloVerifyRequest); msgOk {
+			// DTLS 1.2 clients must not assume that the server will use the protocol version
+			// specified in HelloVerifyRequest message. RFC 6347 Section 4.2.1
+			if !h.Version.Equal(protocol.Version1_0) && !h.Version.Equal(protocol.Version1_2) {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
+			}
+			state.cookie = append([]byte{}, h.Cookie...)
+			state.handshakeRecvSequence = seq
+			return flight3, nil, nil
+		}
+	}
+
+	if cfg.localPSKCallback != nil {
+		seq, msgs, ok = cache.fullPullMap(state.handshakeRecvSequence,
+			handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, true},
+			handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
+		)
+	} else {
+		seq, msgs, ok = cache.fullPullMap(state.handshakeRecvSequence,
+			handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, false, true},
+			handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificateRequest, cfg.initialEpoch, false, true},
+			handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
+		)
+	}
+	if !ok {
+		// Don't have enough messages. Keep reading
+		return 0, nil, nil
+	}
+	state.handshakeRecvSequence = seq
+
+	if h, ok := msgs[handshake.TypeServerHello].(*handshake.MessageServerHello); ok {
+		if !h.Version.Equal(protocol.Version1_2) {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
+		}
+		for _, v := range h.Extensions {
+			switch e := v.(type) {
+			case *extension.UseSRTP:
+				profile, ok := findMatchingSRTPProfile(e.ProtectionProfiles, cfg.localSRTPProtectionProfiles)
+				if !ok {
+					return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, errClientNoMatchingSRTPProfile
+				}
+				state.srtpProtectionProfile = profile
+			case *extension.UseExtendedMasterSecret:
+				if cfg.extendedMasterSecret != DisableExtendedMasterSecret {
+					state.extendedMasterSecret = true
+				}
+			}
+		}
+		if cfg.extendedMasterSecret == RequireExtendedMasterSecret && !state.extendedMasterSecret {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errClientRequiredButNoServerEMS
+		}
+		if len(cfg.localSRTPProtectionProfiles) > 0 && state.srtpProtectionProfile == 0 {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errRequestedButNoSRTPExtension
+		}
+
+		remoteCipherSuite := cipherSuiteForID(CipherSuiteID(*h.CipherSuiteID), cfg.customCipherSuites)
+		if remoteCipherSuite == nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errCipherSuiteNoIntersection
+		}
+
+		selectedCipherSuite, ok := findMatchingCipherSuite([]CipherSuite{remoteCipherSuite}, cfg.localCipherSuites)
+		if !ok {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errInvalidCipherSuite
+		}
+
+		state.cipherSuite = selectedCipherSuite
+		state.remoteRandom = h.Random
+		cfg.log.Tracef("[handshake] use cipher suite: %s", selectedCipherSuite.String())
+	}
+
+	if h, ok := msgs[handshake.TypeCertificate].(*handshake.MessageCertificate); ok {
+		state.PeerCertificates = h.Certificate
+	} else if state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeCertificate {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.NoCertificate}, errInvalidCertificate
+	}
+
+	if h, ok := msgs[handshake.TypeServerKeyExchange].(*handshake.MessageServerKeyExchange); ok {
+		alertPtr, err := handleServerKeyExchange(c, state, cfg, h)
+		if err != nil {
+			return 0, alertPtr, err
+		}
+	}
+
+	if _, ok := msgs[handshake.TypeCertificateRequest].(*handshake.MessageCertificateRequest); ok {
+		state.remoteRequestedCertificate = true
+	}
+
+	return flight5, nil, nil
+}
+
+func handleServerKeyExchange(_ flightConn, state *State, cfg *handshakeConfig, h *handshake.MessageServerKeyExchange) (*alert.Alert, error) {
+	var err error
+	if cfg.localPSKCallback != nil {
+		var psk []byte
+		if psk, err = cfg.localPSKCallback(h.IdentityHint); err != nil {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+		state.IdentityHint = h.IdentityHint
+		state.preMasterSecret = prf.PSKPreMasterSecret(psk)
+	} else {
+		if state.localKeypair, err = elliptic.GenerateKeypair(h.NamedCurve); err != nil {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+
+		if state.preMasterSecret, err = prf.PreMasterSecret(h.PublicKey, state.localKeypair.PrivateKey, state.localKeypair.Curve); err != nil {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+	}
+
+	return nil, nil
+}
+
+func flight3Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
+	extensions := []extension.Extension{
+		&extension.SupportedSignatureAlgorithms{
+			SignatureHashAlgorithms: cfg.localSignatureSchemes,
+		},
+		&extension.RenegotiationInfo{
+			RenegotiatedConnection: 0,
+		},
+	}
+	if cfg.localPSKCallback == nil {
+		extensions = append(extensions, []extension.Extension{
+			&extension.SupportedEllipticCurves{
+				EllipticCurves: []elliptic.Curve{elliptic.X25519, elliptic.P256, elliptic.P384},
+			},
+			&extension.SupportedPointFormats{
+				PointFormats: []elliptic.CurvePointFormat{elliptic.CurvePointFormatUncompressed},
+			},
+		}...)
+	}
+
+	if len(cfg.localSRTPProtectionProfiles) > 0 {
+		extensions = append(extensions, &extension.UseSRTP{
+			ProtectionProfiles: cfg.localSRTPProtectionProfiles,
+		})
+	}
+
+	if cfg.extendedMasterSecret == RequestExtendedMasterSecret ||
+		cfg.extendedMasterSecret == RequireExtendedMasterSecret {
+		extensions = append(extensions, &extension.UseExtendedMasterSecret{
+			Supported: true,
+		})
+	}
+
+	if len(cfg.serverName) > 0 {
+		extensions = append(extensions, &extension.ServerName{ServerName: cfg.serverName})
+	}
+
+	return []*packet{
+		{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageClientHello{
+						Version:            protocol.Version1_2,
+						Cookie:             state.cookie,
+						Random:             state.localRandom,
+						CipherSuiteIDs:     cipherSuiteIDs(cfg.localCipherSuites),
+						CompressionMethods: defaultCompressionMethods(),
+						Extensions:         extensions,
+					},
+				},
+			},
+		},
+	}, nil, nil
+}

dtls-2.0.9/flight4handler.go

@@ -0,0 +1,352 @@
+package dtls
+
+import (
+	"context"
+	"crypto/x509"
+
+	"github.com/pion/dtls/v2/pkg/crypto/clientcertificate"
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/crypto/prf"
+	"github.com/pion/dtls/v2/pkg/crypto/signaturehash"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/extension"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+func flight4Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) { //nolint:gocognit
+	seq, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
+		handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, true, true},
+		handshakeCachePullRule{handshake.TypeClientKeyExchange, cfg.initialEpoch, true, false},
+		handshakeCachePullRule{handshake.TypeCertificateVerify, cfg.initialEpoch, true, true},
+	)
+	if !ok {
+		// No valid message received. Keep reading
+		return 0, nil, nil
+	}
+
+	// Validate type
+	var clientKeyExchange *handshake.MessageClientKeyExchange
+	if clientKeyExchange, ok = msgs[handshake.TypeClientKeyExchange].(*handshake.MessageClientKeyExchange); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+	}
+
+	if h, hasCert := msgs[handshake.TypeCertificate].(*handshake.MessageCertificate); hasCert {
+		state.PeerCertificates = h.Certificate
+	}
+
+	if h, hasCertVerify := msgs[handshake.TypeCertificateVerify].(*handshake.MessageCertificateVerify); hasCertVerify {
+		if state.PeerCertificates == nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.NoCertificate}, errCertificateVerifyNoCertificate
+		}
+
+		plainText := cache.pullAndMerge(
+			handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificateRequest, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeClientKeyExchange, cfg.initialEpoch, true, false},
+		)
+
+		// Verify that the pair of hash algorithm and signiture is listed.
+		var validSignatureScheme bool
+		for _, ss := range cfg.localSignatureSchemes {
+			if ss.Hash == h.HashAlgorithm && ss.Signature == h.SignatureAlgorithm {
+				validSignatureScheme = true
+				break
+			}
+		}
+		if !validSignatureScheme {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errNoAvailableSignatureSchemes
+		}
+
+		if err := verifyCertificateVerify(plainText, h.HashAlgorithm, h.Signature, state.PeerCertificates); err != nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, err
+		}
+		var chains [][]*x509.Certificate
+		var err error
+		var verified bool
+		if cfg.clientAuth >= VerifyClientCertIfGiven {
+			if chains, err = verifyClientCert(state.PeerCertificates, cfg.clientCAs); err != nil {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, err
+			}
+			verified = true
+		}
+		if cfg.verifyPeerCertificate != nil {
+			if err := cfg.verifyPeerCertificate(state.PeerCertificates, chains); err != nil {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, err
+			}
+		}
+		state.peerCertificatesVerified = verified
+	}
+
+	if !state.cipherSuite.IsInitialized() {
+		serverRandom := state.localRandom.MarshalFixed()
+		clientRandom := state.remoteRandom.MarshalFixed()
+
+		var err error
+		var preMasterSecret []byte
+		if state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypePreSharedKey {
+			var psk []byte
+			if psk, err = cfg.localPSKCallback(clientKeyExchange.IdentityHint); err != nil {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+			}
+			state.IdentityHint = clientKeyExchange.IdentityHint
+			preMasterSecret = prf.PSKPreMasterSecret(psk)
+		} else {
+			preMasterSecret, err = prf.PreMasterSecret(clientKeyExchange.PublicKey, state.localKeypair.PrivateKey, state.localKeypair.Curve)
+			if err != nil {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, err
+			}
+		}
+
+		if state.extendedMasterSecret {
+			var sessionHash []byte
+			sessionHash, err = cache.sessionHash(state.cipherSuite.HashFunc(), cfg.initialEpoch)
+			if err != nil {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+			}
+
+			state.masterSecret, err = prf.ExtendedMasterSecret(preMasterSecret, sessionHash, state.cipherSuite.HashFunc())
+			if err != nil {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+			}
+		} else {
+			state.masterSecret, err = prf.MasterSecret(preMasterSecret, clientRandom[:], serverRandom[:], state.cipherSuite.HashFunc())
+			if err != nil {
+				return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+			}
+		}
+
+		if err := state.cipherSuite.Init(state.masterSecret, clientRandom[:], serverRandom[:], false); err != nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+		cfg.writeKeyLog(keyLogLabelTLS12, clientRandom[:], state.masterSecret)
+	}
+
+	// Now, encrypted packets can be handled
+	if err := c.handleQueuedPackets(ctx); err != nil {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+	}
+
+	seq, msgs, ok = cache.fullPullMap(seq,
+		handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, true, false},
+	)
+	if !ok {
+		// No valid message received. Keep reading
+		return 0, nil, nil
+	}
+	state.handshakeRecvSequence = seq
+
+	if _, ok = msgs[handshake.TypeFinished].(*handshake.MessageFinished); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+	}
+
+	if state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeAnonymous {
+		return flight6, nil, nil
+	}
+
+	switch cfg.clientAuth {
+	case RequireAnyClientCert:
+		if state.PeerCertificates == nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.NoCertificate}, errClientCertificateRequired
+		}
+	case VerifyClientCertIfGiven:
+		if state.PeerCertificates != nil && !state.peerCertificatesVerified {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, errClientCertificateNotVerified
+		}
+	case RequireAndVerifyClientCert:
+		if state.PeerCertificates == nil {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.NoCertificate}, errClientCertificateRequired
+		}
+		if !state.peerCertificatesVerified {
+			return 0, &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, errClientCertificateNotVerified
+		}
+	case NoClientCert, RequestClientCert:
+		return flight6, nil, nil
+	}
+
+	return flight6, nil, nil
+}
+
+func flight4Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
+	extensions := []extension.Extension{&extension.RenegotiationInfo{
+		RenegotiatedConnection: 0,
+	}}
+	if (cfg.extendedMasterSecret == RequestExtendedMasterSecret ||
+		cfg.extendedMasterSecret == RequireExtendedMasterSecret) && state.extendedMasterSecret {
+		extensions = append(extensions, &extension.UseExtendedMasterSecret{
+			Supported: true,
+		})
+	}
+	if state.srtpProtectionProfile != 0 {
+		extensions = append(extensions, &extension.UseSRTP{
+			ProtectionProfiles: []SRTPProtectionProfile{state.srtpProtectionProfile},
+		})
+	}
+	if state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeCertificate {
+		extensions = append(extensions, []extension.Extension{
+			&extension.SupportedEllipticCurves{
+				EllipticCurves: []elliptic.Curve{elliptic.X25519, elliptic.P256, elliptic.P384},
+			},
+			&extension.SupportedPointFormats{
+				PointFormats: []elliptic.CurvePointFormat{elliptic.CurvePointFormatUncompressed},
+			},
+		}...)
+	}
+
+	var pkts []*packet
+	cipherSuiteID := uint16(state.cipherSuite.ID())
+
+	pkts = append(pkts, &packet{
+		record: &recordlayer.RecordLayer{
+			Header: recordlayer.Header{
+				Version: protocol.Version1_2,
+			},
+			Content: &handshake.Handshake{
+				Message: &handshake.MessageServerHello{
+					Version:           protocol.Version1_2,
+					Random:            state.localRandom,
+					SessionID:         state.SessionID,
+					CipherSuiteID:     &cipherSuiteID,
+					CompressionMethod: defaultCompressionMethods()[0],
+					Extensions:        extensions,
+				},
+			},
+		},
+	})
+
+	// TODO 添加 CiscoCompat 支持
+	if cfg.localCiscoCompatCallback != nil {
+		if !state.cipherSuite.IsInitialized() {
+			serverRandom := state.localRandom.MarshalFixed()
+			clientRandom := state.remoteRandom.MarshalFixed()
+
+			if err := state.cipherSuite.Init(state.masterSecret, clientRandom[:], serverRandom[:], false); err != nil {
+				return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+			}
+			cfg.writeKeyLog(keyLogLabelTLS12, clientRandom[:], state.masterSecret)
+		}
+		return pkts, nil, nil
+	}
+
+	switch {
+	case state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeCertificate:
+		certificate, err := cfg.getCertificate(cfg.serverName)
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.HandshakeFailure}, err
+		}
+
+		pkts = append(pkts, &packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageCertificate{
+						Certificate: certificate.Certificate,
+					},
+				},
+			},
+		})
+
+		serverRandom := state.localRandom.MarshalFixed()
+		clientRandom := state.remoteRandom.MarshalFixed()
+
+		// Find compatible signature scheme
+		signatureHashAlgo, err := signaturehash.SelectSignatureScheme(cfg.localSignatureSchemes, certificate.PrivateKey)
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, err
+		}
+
+		signature, err := generateKeySignature(clientRandom[:], serverRandom[:], state.localKeypair.PublicKey, state.namedCurve, certificate.PrivateKey, signatureHashAlgo.Hash)
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+		state.localKeySignature = signature
+
+		pkts = append(pkts, &packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageServerKeyExchange{
+						EllipticCurveType:  elliptic.CurveTypeNamedCurve,
+						NamedCurve:         state.namedCurve,
+						PublicKey:          state.localKeypair.PublicKey,
+						HashAlgorithm:      signatureHashAlgo.Hash,
+						SignatureAlgorithm: signatureHashAlgo.Signature,
+						Signature:          state.localKeySignature,
+					},
+				},
+			},
+		})
+
+		if cfg.clientAuth > NoClientCert {
+			pkts = append(pkts, &packet{
+				record: &recordlayer.RecordLayer{
+					Header: recordlayer.Header{
+						Version: protocol.Version1_2,
+					},
+					Content: &handshake.Handshake{
+						Message: &handshake.MessageCertificateRequest{
+							CertificateTypes:        []clientcertificate.Type{clientcertificate.RSASign, clientcertificate.ECDSASign},
+							SignatureHashAlgorithms: cfg.localSignatureSchemes,
+						},
+					},
+				},
+			})
+		}
+	case cfg.localPSKIdentityHint != nil:
+		// To help the client in selecting which identity to use, the server
+		// can provide a "PSK identity hint" in the ServerKeyExchange message.
+		// If no hint is provided, the ServerKeyExchange message is omitted.
+		//
+		// https://tools.ietf.org/html/rfc4279#section-2
+		pkts = append(pkts, &packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageServerKeyExchange{
+						IdentityHint: cfg.localPSKIdentityHint,
+					},
+				},
+			},
+		})
+	case state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeAnonymous:
+		pkts = append(pkts, &packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageServerKeyExchange{
+						EllipticCurveType: elliptic.CurveTypeNamedCurve,
+						NamedCurve:        state.namedCurve,
+						PublicKey:         state.localKeypair.PublicKey,
+					},
+				},
+			},
+		})
+	}
+
+	pkts = append(pkts, &packet{
+		record: &recordlayer.RecordLayer{
+			Header: recordlayer.Header{
+				Version: protocol.Version1_2,
+			},
+			Content: &handshake.Handshake{
+				Message: &handshake.MessageServerHelloDone{},
+			},
+		},
+	})
+
+	return pkts, nil, nil
+}

dtls-2.0.9/flight5handler.go

@@ -0,0 +1,323 @@
+package dtls
+
+import (
+	"bytes"
+	"context"
+	"crypto"
+	"crypto/x509"
+
+	"github.com/pion/dtls/v2/pkg/crypto/prf"
+	"github.com/pion/dtls/v2/pkg/crypto/signaturehash"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+func flight5Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
+	_, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
+		handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, false, false},
+	)
+	if !ok {
+		// No valid message received. Keep reading
+		return 0, nil, nil
+	}
+
+	var finished *handshake.MessageFinished
+	if finished, ok = msgs[handshake.TypeFinished].(*handshake.MessageFinished); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+	}
+	plainText := cache.pullAndMerge(
+		handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+		handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+		handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, false, false},
+		handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
+		handshakeCachePullRule{handshake.TypeCertificateRequest, cfg.initialEpoch, false, false},
+		handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
+		handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, true, false},
+		handshakeCachePullRule{handshake.TypeClientKeyExchange, cfg.initialEpoch, true, false},
+		handshakeCachePullRule{handshake.TypeCertificateVerify, cfg.initialEpoch, true, false},
+		handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, true, false},
+	)
+
+	expectedVerifyData, err := prf.VerifyDataServer(state.masterSecret, plainText, state.cipherSuite.HashFunc())
+	if err != nil {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+	}
+	if !bytes.Equal(expectedVerifyData, finished.VerifyData) {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.HandshakeFailure}, errVerifyDataMismatch
+	}
+
+	return flight5, nil, nil
+}
+
+func flight5Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) { //nolint:gocognit
+	var certBytes [][]byte
+	var privateKey crypto.PrivateKey
+	if len(cfg.localCertificates) > 0 {
+		certificate, err := cfg.getCertificate(cfg.serverName)
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.HandshakeFailure}, err
+		}
+		certBytes = certificate.Certificate
+		privateKey = certificate.PrivateKey
+	}
+
+	var pkts []*packet
+
+	if state.remoteRequestedCertificate {
+		pkts = append(pkts,
+			&packet{
+				record: &recordlayer.RecordLayer{
+					Header: recordlayer.Header{
+						Version: protocol.Version1_2,
+					},
+					Content: &handshake.Handshake{
+						Message: &handshake.MessageCertificate{
+							Certificate: certBytes,
+						},
+					},
+				},
+			})
+	}
+
+	clientKeyExchange := &handshake.MessageClientKeyExchange{}
+	if cfg.localPSKCallback == nil {
+		clientKeyExchange.PublicKey = state.localKeypair.PublicKey
+	} else {
+		clientKeyExchange.IdentityHint = cfg.localPSKIdentityHint
+	}
+
+	pkts = append(pkts,
+		&packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: clientKeyExchange,
+				},
+			},
+		})
+
+	serverKeyExchangeData := cache.pullAndMerge(
+		handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
+	)
+
+	serverKeyExchange := &handshake.MessageServerKeyExchange{}
+
+	// handshakeMessageServerKeyExchange is optional for PSK
+	if len(serverKeyExchangeData) == 0 {
+		alertPtr, err := handleServerKeyExchange(c, state, cfg, &handshake.MessageServerKeyExchange{})
+		if err != nil {
+			return nil, alertPtr, err
+		}
+	} else {
+		rawHandshake := &handshake.Handshake{}
+		err := rawHandshake.Unmarshal(serverKeyExchangeData)
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.UnexpectedMessage}, err
+		}
+
+		switch h := rawHandshake.Message.(type) {
+		case *handshake.MessageServerKeyExchange:
+			serverKeyExchange = h
+		default:
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.UnexpectedMessage}, errInvalidContentType
+		}
+	}
+
+	// Append not-yet-sent packets
+	merged := []byte{}
+	seqPred := uint16(state.handshakeSendSequence)
+	for _, p := range pkts {
+		h, ok := p.record.Content.(*handshake.Handshake)
+		if !ok {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, errInvalidContentType
+		}
+		h.Header.MessageSequence = seqPred
+		seqPred++
+		raw, err := h.Marshal()
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+		merged = append(merged, raw...)
+	}
+
+	if alertPtr, err := initalizeCipherSuite(state, cache, cfg, serverKeyExchange, merged); err != nil {
+		return nil, alertPtr, err
+	}
+
+	// If the client has sent a certificate with signing ability, a digitally-signed
+	// CertificateVerify message is sent to explicitly verify possession of the
+	// private key in the certificate.
+	if state.remoteRequestedCertificate && len(cfg.localCertificates) > 0 {
+		plainText := append(cache.pullAndMerge(
+			handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificateRequest, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeClientKeyExchange, cfg.initialEpoch, true, false},
+		), merged...)
+
+		// Find compatible signature scheme
+		signatureHashAlgo, err := signaturehash.SelectSignatureScheme(cfg.localSignatureSchemes, privateKey)
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, err
+		}
+
+		certVerify, err := generateCertificateVerify(plainText, privateKey, signatureHashAlgo.Hash)
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+		state.localCertificatesVerify = certVerify
+
+		p := &packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageCertificateVerify{
+						HashAlgorithm:      signatureHashAlgo.Hash,
+						SignatureAlgorithm: signatureHashAlgo.Signature,
+						Signature:          state.localCertificatesVerify,
+					},
+				},
+			},
+		}
+		pkts = append(pkts, p)
+
+		h, ok := p.record.Content.(*handshake.Handshake)
+		if !ok {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, errInvalidContentType
+		}
+		h.Header.MessageSequence = seqPred
+		// seqPred++ // this is the last use of seqPred
+		raw, err := h.Marshal()
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+		merged = append(merged, raw...)
+	}
+
+	pkts = append(pkts,
+		&packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &protocol.ChangeCipherSpec{},
+			},
+		})
+
+	if len(state.localVerifyData) == 0 {
+		plainText := cache.pullAndMerge(
+			handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificateRequest, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeClientKeyExchange, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeCertificateVerify, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, true, false},
+		)
+
+		var err error
+		state.localVerifyData, err = prf.VerifyDataClient(state.masterSecret, append(plainText, merged...), state.cipherSuite.HashFunc())
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+	}
+
+	pkts = append(pkts,
+		&packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+					Epoch:   1,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageFinished{
+						VerifyData: state.localVerifyData,
+					},
+				},
+			},
+			shouldEncrypt:            true,
+			resetLocalSequenceNumber: true,
+		})
+
+	return pkts, nil, nil
+}
+
+func initalizeCipherSuite(state *State, cache *handshakeCache, cfg *handshakeConfig, h *handshake.MessageServerKeyExchange, sendingPlainText []byte) (*alert.Alert, error) { //nolint:gocognit
+	if state.cipherSuite.IsInitialized() {
+		return nil, nil
+	}
+
+	clientRandom := state.localRandom.MarshalFixed()
+	serverRandom := state.remoteRandom.MarshalFixed()
+
+	var err error
+
+	if state.extendedMasterSecret {
+		var sessionHash []byte
+		sessionHash, err = cache.sessionHash(state.cipherSuite.HashFunc(), cfg.initialEpoch, sendingPlainText)
+		if err != nil {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+
+		state.masterSecret, err = prf.ExtendedMasterSecret(state.preMasterSecret, sessionHash, state.cipherSuite.HashFunc())
+		if err != nil {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, err
+		}
+	} else {
+		state.masterSecret, err = prf.MasterSecret(state.preMasterSecret, clientRandom[:], serverRandom[:], state.cipherSuite.HashFunc())
+		if err != nil {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+	}
+
+	if state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeCertificate {
+		// Verify that the pair of hash algorithm and signiture is listed.
+		var validSignatureScheme bool
+		for _, ss := range cfg.localSignatureSchemes {
+			if ss.Hash == h.HashAlgorithm && ss.Signature == h.SignatureAlgorithm {
+				validSignatureScheme = true
+				break
+			}
+		}
+		if !validSignatureScheme {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errNoAvailableSignatureSchemes
+		}
+
+		expectedMsg := valueKeyMessage(clientRandom[:], serverRandom[:], h.PublicKey, h.NamedCurve)
+		if err = verifyKeySignature(expectedMsg, h.Signature, h.HashAlgorithm, state.PeerCertificates); err != nil {
+			return &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, err
+		}
+		var chains [][]*x509.Certificate
+		if !cfg.insecureSkipVerify {
+			if chains, err = verifyServerCert(state.PeerCertificates, cfg.rootCAs, cfg.serverName); err != nil {
+				return &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, err
+			}
+		}
+		if cfg.verifyPeerCertificate != nil {
+			if err = cfg.verifyPeerCertificate(state.PeerCertificates, chains); err != nil {
+				return &alert.Alert{Level: alert.Fatal, Description: alert.BadCertificate}, err
+			}
+		}
+	}
+
+	if err = state.cipherSuite.Init(state.masterSecret, clientRandom[:], serverRandom[:], true); err != nil {
+		return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+	}
+
+	cfg.writeKeyLog(keyLogLabelTLS12, clientRandom[:], state.masterSecret)
+
+	return nil, nil
+}

dtls-2.0.9/flight6handler.go

@@ -0,0 +1,82 @@
+package dtls
+
+import (
+	"context"
+
+	"github.com/pion/dtls/v2/pkg/crypto/prf"
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+func flight6Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
+	_, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence-1,
+		handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, true, false},
+	)
+	if !ok {
+		// No valid message received. Keep reading
+		return 0, nil, nil
+	}
+
+	if _, ok = msgs[handshake.TypeFinished].(*handshake.MessageFinished); !ok {
+		return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
+	}
+
+	// Other party retransmitted the last flight.
+	return flight6, nil, nil
+}
+
+func flight6Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
+	var pkts []*packet
+
+	pkts = append(pkts,
+		&packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+				},
+				Content: &protocol.ChangeCipherSpec{},
+			},
+		})
+
+	if len(state.localVerifyData) == 0 {
+		plainText := cache.pullAndMerge(
+			handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificateRequest, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
+			handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeClientKeyExchange, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeCertificateVerify, cfg.initialEpoch, true, false},
+			handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, true, false},
+		)
+
+		var err error
+		state.localVerifyData, err = prf.VerifyDataServer(state.masterSecret, plainText, state.cipherSuite.HashFunc())
+		if err != nil {
+			return nil, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
+		}
+	}
+
+	pkts = append(pkts,
+		&packet{
+			record: &recordlayer.RecordLayer{
+				Header: recordlayer.Header{
+					Version: protocol.Version1_2,
+					Epoch:   1,
+				},
+				Content: &handshake.Handshake{
+					Message: &handshake.MessageFinished{
+						VerifyData: state.localVerifyData,
+					},
+				},
+			},
+			shouldEncrypt:            true,
+			resetLocalSequenceNumber: true,
+		},
+	)
+	return pkts, nil, nil
+}

dtls-2.0.9/flighthandler.go

@@ -0,0 +1,57 @@
+package dtls
+
+import (
+	"context"
+
+	"github.com/pion/dtls/v2/pkg/protocol/alert"
+)
+
+// Parse received handshakes and return next flightVal
+type flightParser func(context.Context, flightConn, *State, *handshakeCache, *handshakeConfig) (flightVal, *alert.Alert, error)
+
+// Generate flights
+type flightGenerator func(flightConn, *State, *handshakeCache, *handshakeConfig) ([]*packet, *alert.Alert, error)
+
+func (f flightVal) getFlightParser() (flightParser, error) {
+	switch f {
+	case flight0:
+		return flight0Parse, nil
+	case flight1:
+		return flight1Parse, nil
+	case flight2:
+		return flight2Parse, nil
+	case flight3:
+		return flight3Parse, nil
+	case flight4:
+		return flight4Parse, nil
+	case flight5:
+		return flight5Parse, nil
+	case flight6:
+		return flight6Parse, nil
+	default:
+		return nil, errInvalidFlight
+	}
+}
+
+func (f flightVal) getFlightGenerator() (gen flightGenerator, retransmit bool, err error) {
+	switch f {
+	case flight0:
+		return flight0Generate, true, nil
+	case flight1:
+		return flight1Generate, true, nil
+	case flight2:
+		// https://tools.ietf.org/html/rfc6347#section-3.2.1
+		// HelloVerifyRequests must not be retransmitted.
+		return flight2Generate, false, nil
+	case flight3:
+		return flight3Generate, true, nil
+	case flight4:
+		return flight4Generate, true, nil
+	case flight5:
+		return flight5Generate, true, nil
+	case flight6:
+		return flight6Generate, true, nil
+	default:
+		return nil, false, errInvalidFlight
+	}
+}

dtls-2.0.9/fragment_buffer.go

@@ -0,0 +1,111 @@
+package dtls
+
+import (
+	"github.com/pion/dtls/v2/pkg/protocol"
+	"github.com/pion/dtls/v2/pkg/protocol/handshake"
+	"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
+)
+
+type fragment struct {
+	recordLayerHeader recordlayer.Header
+	handshakeHeader   handshake.Header
+	data              []byte
+}
+
+type fragmentBuffer struct {
+	// map of MessageSequenceNumbers that hold slices of fragments
+	cache map[uint16][]*fragment
+
+	currentMessageSequenceNumber uint16
+}
+
+func newFragmentBuffer() *fragmentBuffer {
+	return &fragmentBuffer{cache: map[uint16][]*fragment{}}
+}
+
+// Attempts to push a DTLS packet to the fragmentBuffer
+// when it returns true it means the fragmentBuffer has inserted and the buffer shouldn't be handled
+// when an error returns it is fatal, and the DTLS connection should be stopped
+func (f *fragmentBuffer) push(buf []byte) (bool, error) {
+	frag := new(fragment)
+	if err := frag.recordLayerHeader.Unmarshal(buf); err != nil {
+		return false, err
+	}
+
+	// fragment isn't a handshake, we don't need to handle it
+	if frag.recordLayerHeader.ContentType != protocol.ContentTypeHandshake {
+		return false, nil
+	}
+
+	for buf = buf[recordlayer.HeaderSize:]; len(buf) != 0; frag = new(fragment) {
+		if err := frag.handshakeHeader.Unmarshal(buf); err != nil {
+			return false, err
+		}
+
+		if _, ok := f.cache[frag.handshakeHeader.MessageSequence]; !ok {
+			f.cache[frag.handshakeHeader.MessageSequence] = []*fragment{}
+		}
+
+		// end index should be the length of handshake header but if the handshake
+		// was fragmented, we should keep them all
+		end := int(handshake.HeaderLength + frag.handshakeHeader.Length)
+		if size := len(buf); end > size {
+			end = size
+		}
+
+		// Discard all headers, when rebuilding the packet we will re-build
+		frag.data = append([]byte{}, buf[handshake.HeaderLength:end]...)
+		f.cache[frag.handshakeHeader.MessageSequence] = append(f.cache[frag.handshakeHeader.MessageSequence], frag)
+		buf = buf[end:]
+	}
+
+	return true, nil
+}
+
+func (f *fragmentBuffer) pop() (content []byte, epoch uint16) {
+	frags, ok := f.cache[f.currentMessageSequenceNumber]
+	if !ok {
+		return nil, 0
+	}
+
+	// Go doesn't support recursive lambdas
+	var appendMessage func(targetOffset uint32) bool
+
+	rawMessage := []byte{}
+	appendMessage = func(targetOffset uint32) bool {
+		for _, f := range frags {
+			if f.handshakeHeader.FragmentOffset == targetOffset {
+				fragmentEnd := (f.handshakeHeader.FragmentOffset + f.handshakeHeader.FragmentLength)
+				if fragmentEnd != f.handshakeHeader.Length {
+					if !appendMessage(fragmentEnd) {
+						return false
+					}
+				}
+
+				rawMessage = append(f.data, rawMessage...)
+				return true
+			}
+		}
+		return false
+	}
+
+	// Recursively collect up
+	if !appendMessage(0) {
+		return nil, 0
+	}
+
+	firstHeader := frags[0].handshakeHeader
+	firstHeader.FragmentOffset = 0
+	firstHeader.FragmentLength = firstHeader.Length
+
+	rawHeader, err := firstHeader.Marshal()
+	if err != nil {
+		return nil, 0
+	}
+
+	messageEpoch := frags[0].recordLayerHeader.Epoch
+
+	delete(f.cache, f.currentMessageSequenceNumber)
+	f.currentMessageSequenceNumber++
+	return append(rawHeader, rawMessage...), messageEpoch
+}

dtls-2.0.9/fragment_buffer_test.go

@@ -0,0 +1,101 @@
+package dtls
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestFragmentBuffer(t *testing.T) {
+	for _, test := range []struct {
+		Name     string
+		In       [][]byte
+		Expected [][]byte
+		Epoch    uint16
+	}{
+		{
+			Name: "Single Fragment",
+			In: [][]byte{
+				{0x16, 0xfe, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0x03, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xfe, 0xff, 0x00},
+			},
+			Expected: [][]byte{
+				{0x03, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xfe, 0xff, 0x00},
+			},
+			Epoch: 0,
+		},
+		{
+			Name: "Single Fragment Epoch 3",
+			In: [][]byte{
+				{0x16, 0xfe, 0xff, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0x03, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xfe, 0xff, 0x00},
+			},
+			Expected: [][]byte{
+				{0x03, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xfe, 0xff, 0x00},
+			},
+			Epoch: 3,
+		},
+		{
+			Name: "Multiple Fragments",
+			In: [][]byte{
+				{0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0x0b, 0x00, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05, 0x00, 0x01, 0x02, 0x03, 0x04},
+				{0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0x0b, 0x00, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x05, 0x05, 0x06, 0x07, 0x08, 0x09},
+				{0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0x0b, 0x00, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00, 0x0A, 0x00, 0x00, 0x05, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E},
+			},
+			Expected: [][]byte{
+				{0x0b, 0x00, 0x00, 0x0f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0f, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e},
+			},
+			Epoch: 0,
+		},
+		{
+			Name: "Multiple Unordered Fragments",
+			In: [][]byte{
+				{0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0x0b, 0x00, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05, 0x00, 0x01, 0x02, 0x03, 0x04},
+				{0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0x0b, 0x00, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00, 0x0A, 0x00, 0x00, 0x05, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E},
+				{0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x81, 0x0b, 0x00, 0x00, 0x0F, 0x00, 0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x05, 0x05, 0x06, 0x07, 0x08, 0x09},
+			},
+			Expected: [][]byte{
+				{0x0b, 0x00, 0x00, 0x0f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0f, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e},
+			},
+			Epoch: 0,
+		},
+		{
+			Name: "Multiple Handshakes in Signle Fragment",
+			In: [][]byte{
+				{
+					0x16, 0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x30, /* record header */
+					0x03, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0xfe, 0xff, 0x01, 0x01, /*handshake msg 1*/
+					0x03, 0x00, 0x00, 0x04, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0xfe, 0xff, 0x01, 0x01, /*handshake msg 2*/
+					0x03, 0x00, 0x00, 0x04, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0xfe, 0xff, 0x01, 0x01, /*handshake msg 3*/
+				},
+			},
+			Expected: [][]byte{
+				{0x03, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0xfe, 0xff, 0x01, 0x01},
+				{0x03, 0x00, 0x00, 0x04, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0xfe, 0xff, 0x01, 0x01},
+				{0x03, 0x00, 0x00, 0x04, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0xfe, 0xff, 0x01, 0x01},
+			},
+			Epoch: 0,
+		},
+	} {
+		fragmentBuffer := newFragmentBuffer()
+		for _, frag := range test.In {
+			status, err := fragmentBuffer.push(frag)
+			if err != nil {
+				t.Error(err)
+			} else if !status {
+				t.Errorf("fragmentBuffer didn't accept fragments for '%s'", test.Name)
+			}
+		}
+
+		for _, expected := range test.Expected {
+			out, epoch := fragmentBuffer.pop()
+			if !reflect.DeepEqual(out, expected) {
+				t.Errorf("fragmentBuffer '%s' push/pop: got % 02x, want % 02x", test.Name, out, expected)
+			}
+			if epoch != test.Epoch {
+				t.Errorf("fragmentBuffer returned wrong epoch: got %d, want %d", epoch, test.Epoch)
+			}
+		}
+
+		if frag, _ := fragmentBuffer.pop(); frag != nil {
+			t.Errorf("fragmentBuffer popped single buffer multiple times for '%s'", test.Name)
+		}
+	}
+}

dtls-2.0.9/fuzz.go

@@ -0,0 +1,38 @@
+// +build gofuzz
+
+package dtls
+
+import "fmt"
+
+func partialHeaderMismatch(a, b recordlayer.Header) bool {
+	// Ignoring content length for now.
+	a.contentLen = b.contentLen
+	return a != b
+}
+
+func FuzzRecordLayer(data []byte) int {
+	var r recordLayer
+	if err := r.Unmarshal(data); err != nil {
+		return 0
+	}
+	buf, err := r.Marshal()
+	if err != nil {
+		return 1
+	}
+	if len(buf) == 0 {
+		panic("zero buff") // nolint
+	}
+	var nr recordLayer
+	if err = nr.Unmarshal(data); err != nil {
+		panic(err) // nolint
+	}
+	if partialHeaderMismatch(nr.recordlayer.Header, r.recordlayer.Header) {
+		panic( // nolint
+			fmt.Sprintf("header mismatch: %+v != %+v",
+				nr.recordlayer.Header, r.recordlayer.Header,
+			),
+		)
+	}
+
+	return 1
+}

dtls-2.0.9/fuzz/corpus/01277073b27ccc6925ce4c941527f7b7705c8311-1

@@ -0,0 +1 @@
+Ñ12‡™ŠÇ[A51

dtls-2.0.9/fuzz/corpus/137e470b38deeeac3586025e0e6e2702117e26e6

@@ -0,0 +1 @@
+864797660130