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@nigeltao @mattn @Helflym
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris windows
package icmp
import (
"net"
"os"
"runtime"
"syscall"
"golang.org/x/net/internal/iana"
"golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
)
const sysIP_STRIPHDR = 0x17 // for now only darwin supports this option
// ListenPacket listens for incoming ICMP packets addressed to
// address. See net.Dial for the syntax of address.
//
// For non-privileged datagram-oriented ICMP endpoints, network must
// be "udp4" or "udp6". The endpoint allows to read, write a few
// limited ICMP messages such as echo request and echo reply.
// Currently only Darwin and Linux support this.
//
// Examples:
// ListenPacket("udp4", "192.168.0.1")
// ListenPacket("udp4", "0.0.0.0")
// ListenPacket("udp6", "fe80::1%en0")
// ListenPacket("udp6", "::")
//
// For privileged raw ICMP endpoints, network must be "ip4" or "ip6"
// followed by a colon and an ICMP protocol number or name.
//
// Examples:
// ListenPacket("ip4:icmp", "192.168.0.1")
// ListenPacket("ip4:1", "0.0.0.0")
// ListenPacket("ip6:ipv6-icmp", "fe80::1%en0")
// ListenPacket("ip6:58", "::")
func ListenPacket(network, address string) (*PacketConn, error) {
var family, proto int
switch network {
case "udp4":
family, proto = syscall.AF_INET, iana.ProtocolICMP
case "udp6":
family, proto = syscall.AF_INET6, iana.ProtocolIPv6ICMP
default:
i := last(network, ':')
switch network[:i] {
case "ip4":
proto = iana.ProtocolICMP
case "ip6":
proto = iana.ProtocolIPv6ICMP
}
}
var cerr error
var c net.PacketConn
switch family {
case syscall.AF_INET, syscall.AF_INET6:
s, err := syscall.Socket(family, syscall.SOCK_DGRAM, proto)
if err != nil {
return nil, os.NewSyscallError("socket", err)
}
if runtime.GOOS == "darwin" && family == syscall.AF_INET {
if err := syscall.SetsockoptInt(s, iana.ProtocolIP, sysIP_STRIPHDR, 1); err != nil {
syscall.Close(s)
return nil, os.NewSyscallError("setsockopt", err)
}
}
sa, err := sockaddr(family, address)
if err != nil {
syscall.Close(s)
return nil, err
}
if err := syscall.Bind(s, sa); err != nil {
syscall.Close(s)
return nil, os.NewSyscallError("bind", err)
}
f := os.NewFile(uintptr(s), "datagram-oriented icmp")
c, cerr = net.FilePacketConn(f)
f.Close()
default:
c, cerr = net.ListenPacket(network, address)
}
if cerr != nil {
return nil, cerr
}
switch proto {
case iana.ProtocolICMP:
return &PacketConn{c: c, p4: ipv4.NewPacketConn(c)}, nil
case iana.ProtocolIPv6ICMP:
return &PacketConn{c: c, p6: ipv6.NewPacketConn(c)}, nil
default:
return &PacketConn{c: c}, nil
}
}
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