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我想UDP數據包發送到遠程主機這樣發送UDP數據包gopacket
conn, err := net.ListenPacket("ip4:udp", "0.0.0.0")
if err != nil {
panic(err)
}
ip := &layers.IPv4{
SrcIP: saddr,
DstIP: dip,
Protocol: layers.IPProtocolUDP,
}
udp := &layers.UDP{
SrcPort: layers.UDPPort(sport),
DstPort: layers.UDPPort(us.Port),
}
udp.SetNetworkLayerForChecksum(ip)
buf := gopacket.NewSerializeBuffer()
opts := gopacket.SerializeOptions{
ComputeChecksums: true,
FixLengths: true,
}
if err := gopacket.SerializeLayers(buf, opts, udp); err != nil {
fmt.Printf("%v", err)
}
if _, err := us.Conn.WriteTo(buf.Bytes(), &net.IPAddr{IP: dip}); err != nil {
panic(err)
}
// reading
for {
buf2 := make([]byte, 4096)
n, addr, err := us.Conn.ReadFrom(buf2)
if err != nil {
fmt.Printf("%v", err)
}
if addr.String() == dip.String() {
fmt.Printf("Got a reply")
}
}
但這種不斷犯錯了,而與read ip4 0.0.0.0: i/o timeout
讀取數據包。當我tcpdump時,我看到數據包被髮送出去,一個UDP響應在端口53上返回,都是ICMP。爲什麼我的代碼不能讀取這些數據包?