github.com/Andyfoo/golang/x/net@v0.0.0-20190901054642-57c1bf301704/icmp/listen_posix.go (about)

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build aix darwin dragonfly freebsd linux netbsd openbsd solaris windows
     6  
     7  package icmp
     8  
     9  import (
    10  	"net"
    11  	"os"
    12  	"runtime"
    13  	"syscall"
    14  
    15  	"github.com/Andyfoo/golang/x/net/internal/iana"
    16  	"github.com/Andyfoo/golang/x/net/ipv4"
    17  	"github.com/Andyfoo/golang/x/net/ipv6"
    18  )
    19  
    20  const sysIP_STRIPHDR = 0x17 // for now only darwin supports this option
    21  
    22  // ListenPacket listens for incoming ICMP packets addressed to
    23  // address. See net.Dial for the syntax of address.
    24  //
    25  // For non-privileged datagram-oriented ICMP endpoints, network must
    26  // be "udp4" or "udp6". The endpoint allows to read, write a few
    27  // limited ICMP messages such as echo request and echo reply.
    28  // Currently only Darwin and Linux support this.
    29  //
    30  // Examples:
    31  //	ListenPacket("udp4", "192.168.0.1")
    32  //	ListenPacket("udp4", "0.0.0.0")
    33  //	ListenPacket("udp6", "fe80::1%en0")
    34  //	ListenPacket("udp6", "::")
    35  //
    36  // For privileged raw ICMP endpoints, network must be "ip4" or "ip6"
    37  // followed by a colon and an ICMP protocol number or name.
    38  //
    39  // Examples:
    40  //	ListenPacket("ip4:icmp", "192.168.0.1")
    41  //	ListenPacket("ip4:1", "0.0.0.0")
    42  //	ListenPacket("ip6:ipv6-icmp", "fe80::1%en0")
    43  //	ListenPacket("ip6:58", "::")
    44  func ListenPacket(network, address string) (*PacketConn, error) {
    45  	var family, proto int
    46  	switch network {
    47  	case "udp4":
    48  		family, proto = syscall.AF_INET, iana.ProtocolICMP
    49  	case "udp6":
    50  		family, proto = syscall.AF_INET6, iana.ProtocolIPv6ICMP
    51  	default:
    52  		i := last(network, ':')
    53  		switch network[:i] {
    54  		case "ip4":
    55  			proto = iana.ProtocolICMP
    56  		case "ip6":
    57  			proto = iana.ProtocolIPv6ICMP
    58  		}
    59  	}
    60  	var cerr error
    61  	var c net.PacketConn
    62  	switch family {
    63  	case syscall.AF_INET, syscall.AF_INET6:
    64  		s, err := syscall.Socket(family, syscall.SOCK_DGRAM, proto)
    65  		if err != nil {
    66  			return nil, os.NewSyscallError("socket", err)
    67  		}
    68  		if runtime.GOOS == "darwin" && family == syscall.AF_INET {
    69  			if err := syscall.SetsockoptInt(s, iana.ProtocolIP, sysIP_STRIPHDR, 1); err != nil {
    70  				syscall.Close(s)
    71  				return nil, os.NewSyscallError("setsockopt", err)
    72  			}
    73  		}
    74  		sa, err := sockaddr(family, address)
    75  		if err != nil {
    76  			syscall.Close(s)
    77  			return nil, err
    78  		}
    79  		if err := syscall.Bind(s, sa); err != nil {
    80  			syscall.Close(s)
    81  			return nil, os.NewSyscallError("bind", err)
    82  		}
    83  		f := os.NewFile(uintptr(s), "datagram-oriented icmp")
    84  		c, cerr = net.FilePacketConn(f)
    85  		f.Close()
    86  	default:
    87  		c, cerr = net.ListenPacket(network, address)
    88  	}
    89  	if cerr != nil {
    90  		return nil, cerr
    91  	}
    92  	switch proto {
    93  	case iana.ProtocolICMP:
    94  		return &PacketConn{c: c, p4: ipv4.NewPacketConn(c)}, nil
    95  	case iana.ProtocolIPv6ICMP:
    96  		return &PacketConn{c: c, p6: ipv6.NewPacketConn(c)}, nil
    97  	default:
    98  		return &PacketConn{c: c}, nil
    99  	}
   100  }