添加 github.com/pion/dtls 代码

dtls-2.0.9/pkg/protocol/handshake/handshake.go

@@ -0,0 +1,145 @@
+// Package handshake provides the DTLS wire protocol for handshakes
+package handshake
+
+import (
+	"github.com/pion/dtls/v2/internal/util"
+	"github.com/pion/dtls/v2/pkg/protocol"
+)
+
+// Type is the unique identifier for each handshake message
+// https://tools.ietf.org/html/rfc5246#section-7.4
+type Type uint8
+
+// Types of DTLS Handshake messages we know about
+const (
+	TypeHelloRequest       Type = 0
+	TypeClientHello        Type = 1
+	TypeServerHello        Type = 2
+	TypeHelloVerifyRequest Type = 3
+	TypeCertificate        Type = 11
+	TypeServerKeyExchange  Type = 12
+	TypeCertificateRequest Type = 13
+	TypeServerHelloDone    Type = 14
+	TypeCertificateVerify  Type = 15
+	TypeClientKeyExchange  Type = 16
+	TypeFinished           Type = 20
+)
+
+// String returns the string representation of this type
+func (t Type) String() string {
+	switch t {
+	case TypeHelloRequest:
+		return "HelloRequest"
+	case TypeClientHello:
+		return "ClientHello"
+	case TypeServerHello:
+		return "ServerHello"
+	case TypeHelloVerifyRequest:
+		return "HelloVerifyRequest"
+	case TypeCertificate:
+		return "TypeCertificate"
+	case TypeServerKeyExchange:
+		return "ServerKeyExchange"
+	case TypeCertificateRequest:
+		return "CertificateRequest"
+	case TypeServerHelloDone:
+		return "ServerHelloDone"
+	case TypeCertificateVerify:
+		return "CertificateVerify"
+	case TypeClientKeyExchange:
+		return "ClientKeyExchange"
+	case TypeFinished:
+		return "Finished"
+	}
+	return ""
+}
+
+// Message is the body of a Handshake datagram
+type Message interface {
+	Marshal() ([]byte, error)
+	Unmarshal(data []byte) error
+
+	Type() Type
+}
+
+// Handshake protocol is responsible for selecting a cipher spec and
+// generating a master secret, which together comprise the primary
+// cryptographic parameters associated with a secure session.  The
+// handshake protocol can also optionally authenticate parties who have
+// certificates signed by a trusted certificate authority.
+// https://tools.ietf.org/html/rfc5246#section-7.3
+type Handshake struct {
+	Header  Header
+	Message Message
+}
+
+// ContentType returns what kind of content this message is carying
+func (h Handshake) ContentType() protocol.ContentType {
+	return protocol.ContentTypeHandshake
+}
+
+// Marshal encodes a handshake into a binary message
+func (h *Handshake) Marshal() ([]byte, error) {
+	if h.Message == nil {
+		return nil, errHandshakeMessageUnset
+	} else if h.Header.FragmentOffset != 0 {
+		return nil, errUnableToMarshalFragmented
+	}
+
+	msg, err := h.Message.Marshal()
+	if err != nil {
+		return nil, err
+	}
+
+	h.Header.Length = uint32(len(msg))
+	h.Header.FragmentLength = h.Header.Length
+	h.Header.Type = h.Message.Type()
+	header, err := h.Header.Marshal()
+	if err != nil {
+		return nil, err
+	}
+
+	return append(header, msg...), nil
+}
+
+// Unmarshal decodes a handshake from a binary message
+func (h *Handshake) Unmarshal(data []byte) error {
+	if err := h.Header.Unmarshal(data); err != nil {
+		return err
+	}
+
+	reportedLen := util.BigEndianUint24(data[1:])
+	if uint32(len(data)-HeaderLength) != reportedLen {
+		return errLengthMismatch
+	} else if reportedLen != h.Header.FragmentLength {
+		return errLengthMismatch
+	}
+
+	switch Type(data[0]) {
+	case TypeHelloRequest:
+		return errNotImplemented
+	case TypeClientHello:
+		h.Message = &MessageClientHello{}
+	case TypeHelloVerifyRequest:
+		h.Message = &MessageHelloVerifyRequest{}
+	case TypeServerHello:
+		h.Message = &MessageServerHello{}
+	case TypeCertificate:
+		h.Message = &MessageCertificate{}
+	case TypeServerKeyExchange:
+		h.Message = &MessageServerKeyExchange{}
+	case TypeCertificateRequest:
+		h.Message = &MessageCertificateRequest{}
+	case TypeServerHelloDone:
+		h.Message = &MessageServerHelloDone{}
+	case TypeClientKeyExchange:
+		h.Message = &MessageClientKeyExchange{}
+	case TypeFinished:
+		h.Message = &MessageFinished{}
+	case TypeCertificateVerify:
+		h.Message = &MessageCertificateVerify{}
+	default:
+		return errNotImplemented
+	}
+	return h.Message.Unmarshal(data[HeaderLength:])
+}