// 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, ':') if i < 0 { i = len(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 } }