libgo/go/net/iprawsock.go

   1 // Copyright 2010 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 package net
   6
   7 import (
   8         "context"
   9         "syscall"
  10 )
  11
  12 // BUG(mikio): On every POSIX platform, reads from the "ip4" network
  13 // using the ReadFrom or ReadFromIP method might not return a complete
  14 // IPv4 packet, including its header, even if there is space
  15 // available. This can occur even in cases where Read or ReadMsgIP
  16 // could return a complete packet. For this reason, it is recommended
  17 // that you do not use these methods if it is important to receive a
  18 // full packet.
  19 //
  20 // The Go 1 compatibility guidelines make it impossible for us to
  21 // change the behavior of these methods; use Read or ReadMsgIP
  22 // instead.
  23
  24 // BUG(mikio): On NaCl, Plan 9 and Windows, the ReadMsgIP and
  25 // WriteMsgIP methods of IPConn are not implemented.
  26
  27 // BUG(mikio): On Windows, the File method of IPConn is not
  28 // implemented.
  29
  30 // IPAddr represents the address of an IP end point.
  31 type IPAddr struct {
  32         IP   IP
  33         Zone string // IPv6 scoped addressing zone
  34 }
  35
  36 // Network returns the address's network name, "ip".
  37 func (a *IPAddr) Network() string { return "ip" }
  38
  39 func (a *IPAddr) String() string {
  40         if a == nil {
  41                 return "<nil>"
  42         }
  43         ip := ipEmptyString(a.IP)
  44         if a.Zone != "" {
  45                 return ip + "%" + a.Zone
  46         }
  47         return ip
  48 }
  49
  50 func (a *IPAddr) isWildcard() bool {
  51         if a == nil || a.IP == nil {
  52                 return true
  53         }
  54         return a.IP.IsUnspecified()
  55 }
  56
  57 func (a *IPAddr) opAddr() Addr {
  58         if a == nil {
  59                 return nil
  60         }
  61         return a
  62 }
  63
  64 // ResolveIPAddr parses addr as an IP address of the form "host" or
  65 // "ipv6-host%zone" and resolves the domain name on the network net,
  66 // which must be "ip", "ip4" or "ip6".
  67 //
  68 // Resolving a hostname is not recommended because this returns at most
  69 // one of its IP addresses.
  70 func ResolveIPAddr(net, addr string) (*IPAddr, error) {
  71         if net == "" { // a hint wildcard for Go 1.0 undocumented behavior
  72                 net = "ip"
  73         }
  74         afnet, _, err := parseNetwork(context.Background(), net)
  75         if err != nil {
  76                 return nil, err
  77         }
  78         switch afnet {
  79         case "ip", "ip4", "ip6":
  80         default:
  81                 return nil, UnknownNetworkError(net)
  82         }
  83         addrs, err := DefaultResolver.internetAddrList(context.Background(), afnet, addr)
  84         if err != nil {
  85                 return nil, err
  86         }
  87         return addrs.first(isIPv4).(*IPAddr), nil
  88 }
  89
  90 // IPConn is the implementation of the Conn and PacketConn interfaces
  91 // for IP network connections.
  92 type IPConn struct {
  93         conn
  94 }
  95
  96 // ReadFromIP reads an IP packet from c, copying the payload into b.
  97 // It returns the number of bytes copied into b and the return address
  98 // that was on the packet.
  99 //
 100 // ReadFromIP can be made to time out and return an error with
 101 // Timeout() == true after a fixed time limit; see SetDeadline and
 102 // SetReadDeadline.
 103 func (c *IPConn) ReadFromIP(b []byte) (int, *IPAddr, error) {
 104         if !c.ok() {
 105                 return 0, nil, syscall.EINVAL
 106         }
 107         n, addr, err := c.readFrom(b)
 108         if err != nil {
 109                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 110         }
 111         return n, addr, err
 112 }
 113
 114 // ReadFrom implements the PacketConn ReadFrom method.
 115 func (c *IPConn) ReadFrom(b []byte) (int, Addr, error) {
 116         if !c.ok() {
 117                 return 0, nil, syscall.EINVAL
 118         }
 119         n, addr, err := c.readFrom(b)
 120         if err != nil {
 121                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 122         }
 123         if addr == nil {
 124                 return n, nil, err
 125         }
 126         return n, addr, err
 127 }
 128
 129 // ReadMsgIP reads a packet from c, copying the payload into b and the
 130 // associated out-of-band data into oob. It returns the number of
 131 // bytes copied into b, the number of bytes copied into oob, the flags
 132 // that were set on the packet and the source address of the packet.
 133 func (c *IPConn) ReadMsgIP(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
 134         if !c.ok() {
 135                 return 0, 0, 0, nil, syscall.EINVAL
 136         }
 137         n, oobn, flags, addr, err = c.readMsg(b, oob)
 138         if err != nil {
 139                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 140         }
 141         return
 142 }
 143
 144 // WriteToIP writes an IP packet to addr via c, copying the payload
 145 // from b.
 146 //
 147 // WriteToIP can be made to time out and return an error with
 148 // Timeout() == true after a fixed time limit; see SetDeadline and
 149 // SetWriteDeadline. On packet-oriented connections, write timeouts
 150 // are rare.
 151 func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (int, error) {
 152         if !c.ok() {
 153                 return 0, syscall.EINVAL
 154         }
 155         n, err := c.writeTo(b, addr)
 156         if err != nil {
 157                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 158         }
 159         return n, err
 160 }
 161
 162 // WriteTo implements the PacketConn WriteTo method.
 163 func (c *IPConn) WriteTo(b []byte, addr Addr) (int, error) {
 164         if !c.ok() {
 165                 return 0, syscall.EINVAL
 166         }
 167         a, ok := addr.(*IPAddr)
 168         if !ok {
 169                 return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
 170         }
 171         n, err := c.writeTo(b, a)
 172         if err != nil {
 173                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
 174         }
 175         return n, err
 176 }
 177
 178 // WriteMsgIP writes a packet to addr via c, copying the payload from
 179 // b and the associated out-of-band data from oob. It returns the
 180 // number of payload and out-of-band bytes written.
 181 func (c *IPConn) WriteMsgIP(b, oob []byte, addr *IPAddr) (n, oobn int, err error) {
 182         if !c.ok() {
 183                 return 0, 0, syscall.EINVAL
 184         }
 185         n, oobn, err = c.writeMsg(b, oob, addr)
 186         if err != nil {
 187                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 188         }
 189         return
 190 }
 191
 192 func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
 193
 194 // DialIP connects to the remote address raddr on the network protocol
 195 // netProto, which must be "ip", "ip4", or "ip6" followed by a colon
 196 // and a protocol number or name.
 197 func DialIP(netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
 198         c, err := dialIP(context.Background(), netProto, laddr, raddr)
 199         if err != nil {
 200                 return nil, &OpError{Op: "dial", Net: netProto, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 201         }
 202         return c, nil
 203 }
 204
 205 // ListenIP listens for incoming IP packets addressed to the local
 206 // address laddr. The returned connection's ReadFrom and WriteTo
 207 // methods can be used to receive and send IP packets with per-packet
 208 // addressing.
 209 func ListenIP(netProto string, laddr *IPAddr) (*IPConn, error) {
 210         c, err := listenIP(context.Background(), netProto, laddr)
 211         if err != nil {
 212                 return nil, &OpError{Op: "listen", Net: netProto, Source: nil, Addr: laddr.opAddr(), Err: err}
 213         }
 214         return c, nil
 215 }