优化抓包性能

vendor/github.com/google/gopacket/pcap/pcap_tester.go

@@ -0,0 +1,108 @@
+// Copyright 2012 Google, Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+// +build ignore
+
+// This binary tests that PCAP packet capture is working correctly by issuing
+// HTTP requests, then making sure we actually capture data off the wire.
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/google/gopacket/pcap"
+)
+
+var mode = flag.String("mode", "basic", "One of: basic,filtered,timestamp")
+
+func generatePackets() {
+	if resp, err := http.Get("http://code.google.com"); err != nil {
+		log.Printf("Could not get HTTP: %v", err)
+	} else {
+		resp.Body.Close()
+	}
+}
+
+func main() {
+	flag.Parse()
+	ifaces, err := pcap.FindAllDevs()
+	if err != nil {
+		log.Fatal(err)
+	}
+	for _, iface := range ifaces {
+		log.Printf("Trying capture on %q", iface.Name)
+		if err := tryCapture(iface); err != nil {
+			log.Printf("Error capturing on %q: %v", iface.Name, err)
+		} else {
+			log.Printf("Successfully captured on %q", iface.Name)
+			return
+		}
+	}
+	os.Exit(1)
+}
+
+func tryCapture(iface pcap.Interface) error {
+	if iface.Name[:2] == "lo" {
+		return errors.New("skipping loopback")
+	}
+	var h *pcap.Handle
+	var err error
+	switch *mode {
+	case "basic":
+		h, err = pcap.OpenLive(iface.Name, 65536, false, time.Second*3)
+		if err != nil {
+			return fmt.Errorf("openlive: %v", err)
+		}
+		defer h.Close()
+	case "filtered":
+		h, err = pcap.OpenLive(iface.Name, 65536, false, time.Second*3)
+		if err != nil {
+			return fmt.Errorf("openlive: %v", err)
+		}
+		defer h.Close()
+		if err := h.SetBPFFilter("port 80 or port 443"); err != nil {
+			return fmt.Errorf("setbpf: %v", err)
+		}
+	case "timestamp":
+		u, err := pcap.NewInactiveHandle(iface.Name)
+		if err != nil {
+			return err
+		}
+		defer u.CleanUp()
+		if err = u.SetSnapLen(65536); err != nil {
+			return err
+		} else if err = u.SetPromisc(false); err != nil {
+			return err
+		} else if err = u.SetTimeout(time.Second * 3); err != nil {
+			return err
+		}
+		sources := u.SupportedTimestamps()
+		if len(sources) == 0 {
+			return errors.New("no supported timestamp sources")
+		} else if err := u.SetTimestampSource(sources[0]); err != nil {
+			return fmt.Errorf("settimestampsource(%v): %v", sources[0], err)
+		} else if h, err = u.Activate(); err != nil {
+			return fmt.Errorf("could not activate: %v", err)
+		}
+		defer h.Close()
+	default:
+		panic("Invalid --mode: " + *mode)
+	}
+	go generatePackets()
+	h.ReadPacketData() // Do one dummy read to clear any timeouts.
+	data, ci, err := h.ReadPacketData()
+	if err != nil {
+		return fmt.Errorf("readpacketdata: %v", err)
+	}
+	log.Printf("Read packet, %v bytes, CI: %+v", len(data), ci)
+	return nil
+}