David K. Bainbridge | 215e024 | 2017-09-05 23:18:24 -0700 | [diff] [blame^] | 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 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 | "golang.org/x/net/internal/iana" |
| 16 | "golang.org/x/net/ipv4" |
| 17 | "golang.org/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 | } |