libgo/go/net/udpsock.go

   1 // Copyright 2009 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 Plan 9, the ReadMsgUDP and
  13 // WriteMsgUDP methods of UDPConn are not implemented.
  14
  15 // BUG(mikio): On Windows, the File method of UDPConn is not
  16 // implemented.
  17
  18 // BUG(mikio): On JS, methods and functions related to UDPConn are not
  19 // implemented.
  20
  21 // UDPAddr represents the address of a UDP end point.
  22 type UDPAddr struct {
  23         IP   IP
  24         Port int
  25         Zone string // IPv6 scoped addressing zone
  26 }
  27
  28 // Network returns the address's network name, "udp".
  29 func (a *UDPAddr) Network() string { return "udp" }
  30
  31 func (a *UDPAddr) String() string {
  32         if a == nil {
  33                 return "<nil>"
  34         }
  35         ip := ipEmptyString(a.IP)
  36         if a.Zone != "" {
  37                 return JoinHostPort(ip+"%"+a.Zone, itoa(a.Port))
  38         }
  39         return JoinHostPort(ip, itoa(a.Port))
  40 }
  41
  42 func (a *UDPAddr) isWildcard() bool {
  43         if a == nil || a.IP == nil {
  44                 return true
  45         }
  46         return a.IP.IsUnspecified()
  47 }
  48
  49 func (a *UDPAddr) opAddr() Addr {
  50         if a == nil {
  51                 return nil
  52         }
  53         return a
  54 }
  55
  56 // ResolveUDPAddr returns an address of UDP end point.
  57 //
  58 // The network must be a UDP network name.
  59 //
  60 // If the host in the address parameter is not a literal IP address or
  61 // the port is not a literal port number, ResolveUDPAddr resolves the
  62 // address to an address of UDP end point.
  63 // Otherwise, it parses the address as a pair of literal IP address
  64 // and port number.
  65 // The address parameter can use a host name, but this is not
  66 // recommended, because it will return at most one of the host name's
  67 // IP addresses.
  68 //
  69 // See func Dial for a description of the network and address
  70 // parameters.
  71 func ResolveUDPAddr(network, address string) (*UDPAddr, error) {
  72         switch network {
  73         case "udp", "udp4", "udp6":
  74         case "": // a hint wildcard for Go 1.0 undocumented behavior
  75                 network = "udp"
  76         default:
  77                 return nil, UnknownNetworkError(network)
  78         }
  79         addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
  80         if err != nil {
  81                 return nil, err
  82         }
  83         return addrs.forResolve(network, address).(*UDPAddr), nil
  84 }
  85
  86 // UDPConn is the implementation of the Conn and PacketConn interfaces
  87 // for UDP network connections.
  88 type UDPConn struct {
  89         conn
  90 }
  91
  92 // SyscallConn returns a raw network connection.
  93 // This implements the syscall.Conn interface.
  94 func (c *UDPConn) SyscallConn() (syscall.RawConn, error) {
  95         if !c.ok() {
  96                 return nil, syscall.EINVAL
  97         }
  98         return newRawConn(c.fd)
  99 }
 100
 101 // ReadFromUDP acts like ReadFrom but returns a UDPAddr.
 102 func (c *UDPConn) ReadFromUDP(b []byte) (int, *UDPAddr, error) {
 103         if !c.ok() {
 104                 return 0, nil, syscall.EINVAL
 105         }
 106         n, addr, err := c.readFrom(b)
 107         if err != nil {
 108                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 109         }
 110         return n, addr, err
 111 }
 112
 113 // ReadFrom implements the PacketConn ReadFrom method.
 114 func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) {
 115         if !c.ok() {
 116                 return 0, nil, syscall.EINVAL
 117         }
 118         n, addr, err := c.readFrom(b)
 119         if err != nil {
 120                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 121         }
 122         if addr == nil {
 123                 return n, nil, err
 124         }
 125         return n, addr, err
 126 }
 127
 128 // ReadMsgUDP reads a message from c, copying the payload into b and
 129 // the associated out-of-band data into oob. It returns the number of
 130 // bytes copied into b, the number of bytes copied into oob, the flags
 131 // that were set on the message and the source address of the message.
 132 //
 133 // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
 134 // used to manipulate IP-level socket options in oob.
 135 func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
 136         if !c.ok() {
 137                 return 0, 0, 0, nil, syscall.EINVAL
 138         }
 139         n, oobn, flags, addr, err = c.readMsg(b, oob)
 140         if err != nil {
 141                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 142         }
 143         return
 144 }
 145
 146 // WriteToUDP acts like WriteTo but takes a UDPAddr.
 147 func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) {
 148         if !c.ok() {
 149                 return 0, syscall.EINVAL
 150         }
 151         n, err := c.writeTo(b, addr)
 152         if err != nil {
 153                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 154         }
 155         return n, err
 156 }
 157
 158 // WriteTo implements the PacketConn WriteTo method.
 159 func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) {
 160         if !c.ok() {
 161                 return 0, syscall.EINVAL
 162         }
 163         a, ok := addr.(*UDPAddr)
 164         if !ok {
 165                 return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
 166         }
 167         n, err := c.writeTo(b, a)
 168         if err != nil {
 169                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
 170         }
 171         return n, err
 172 }
 173
 174 // WriteMsgUDP writes a message to addr via c if c isn't connected, or
 175 // to c's remote address if c is connected (in which case addr must be
 176 // nil). The payload is copied from b and the associated out-of-band
 177 // data is copied from oob. It returns the number of payload and
 178 // out-of-band bytes written.
 179 //
 180 // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
 181 // used to manipulate IP-level socket options in oob.
 182 func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
 183         if !c.ok() {
 184                 return 0, 0, syscall.EINVAL
 185         }
 186         n, oobn, err = c.writeMsg(b, oob, addr)
 187         if err != nil {
 188                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 189         }
 190         return
 191 }
 192
 193 func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
 194
 195 // DialUDP acts like Dial for UDP networks.
 196 //
 197 // The network must be a UDP network name; see func Dial for details.
 198 //
 199 // If laddr is nil, a local address is automatically chosen.
 200 // If the IP field of raddr is nil or an unspecified IP address, the
 201 // local system is assumed.
 202 func DialUDP(network string, laddr, raddr *UDPAddr) (*UDPConn, error) {
 203         switch network {
 204         case "udp", "udp4", "udp6":
 205         default:
 206                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
 207         }
 208         if raddr == nil {
 209                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
 210         }
 211         sd := &sysDialer{network: network, address: raddr.String()}
 212         c, err := sd.dialUDP(context.Background(), laddr, raddr)
 213         if err != nil {
 214                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 215         }
 216         return c, nil
 217 }
 218
 219 // ListenUDP acts like ListenPacket for UDP networks.
 220 //
 221 // The network must be a UDP network name; see func Dial for details.
 222 //
 223 // If the IP field of laddr is nil or an unspecified IP address,
 224 // ListenUDP listens on all available IP addresses of the local system
 225 // except multicast IP addresses.
 226 // If the Port field of laddr is 0, a port number is automatically
 227 // chosen.
 228 func ListenUDP(network string, laddr *UDPAddr) (*UDPConn, error) {
 229         switch network {
 230         case "udp", "udp4", "udp6":
 231         default:
 232                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)}
 233         }
 234         if laddr == nil {
 235                 laddr = &UDPAddr{}
 236         }
 237         sl := &sysListener{network: network, address: laddr.String()}
 238         c, err := sl.listenUDP(context.Background(), laddr)
 239         if err != nil {
 240                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
 241         }
 242         return c, nil
 243 }
 244
 245 // ListenMulticastUDP acts like ListenPacket for UDP networks but
 246 // takes a group address on a specific network interface.
 247 //
 248 // The network must be a UDP network name; see func Dial for details.
 249 //
 250 // ListenMulticastUDP listens on all available IP addresses of the
 251 // local system including the group, multicast IP address.
 252 // If ifi is nil, ListenMulticastUDP uses the system-assigned
 253 // multicast interface, although this is not recommended because the
 254 // assignment depends on platforms and sometimes it might require
 255 // routing configuration.
 256 // If the Port field of gaddr is 0, a port number is automatically
 257 // chosen.
 258 //
 259 // ListenMulticastUDP is just for convenience of simple, small
 260 // applications. There are golang.org/x/net/ipv4 and
 261 // golang.org/x/net/ipv6 packages for general purpose uses.
 262 func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
 263         switch network {
 264         case "udp", "udp4", "udp6":
 265         default:
 266                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: UnknownNetworkError(network)}
 267         }
 268         if gaddr == nil || gaddr.IP == nil {
 269                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: errMissingAddress}
 270         }
 271         sl := &sysListener{network: network, address: gaddr.String()}
 272         c, err := sl.listenMulticastUDP(context.Background(), ifi, gaddr)
 273         if err != nil {
 274                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: err}
 275         }
 276         return c, nil
 277 }