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 NaCl and 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 NaCl, the ListenMulticastUDP function is not
  19 // implemented.
  20
  21 // BUG(mikio): On JS, methods and functions related to UDPConn are not
  22 // implemented.
  23
  24 // UDPAddr represents the address of a UDP end point.
  25 type UDPAddr struct {
  26         IP   IP
  27         Port int
  28         Zone string // IPv6 scoped addressing zone
  29 }
  30
  31 // Network returns the address's network name, "udp".
  32 func (a *UDPAddr) Network() string { return "udp" }
  33
  34 func (a *UDPAddr) String() string {
  35         if a == nil {
  36                 return "<nil>"
  37         }
  38         ip := ipEmptyString(a.IP)
  39         if a.Zone != "" {
  40                 return JoinHostPort(ip+"%"+a.Zone, itoa(a.Port))
  41         }
  42         return JoinHostPort(ip, itoa(a.Port))
  43 }
  44
  45 func (a *UDPAddr) isWildcard() bool {
  46         if a == nil || a.IP == nil {
  47                 return true
  48         }
  49         return a.IP.IsUnspecified()
  50 }
  51
  52 func (a *UDPAddr) opAddr() Addr {
  53         if a == nil {
  54                 return nil
  55         }
  56         return a
  57 }
  58
  59 // ResolveUDPAddr returns an address of UDP end point.
  60 //
  61 // The network must be a UDP network name.
  62 //
  63 // If the host in the address parameter is not a literal IP address or
  64 // the port is not a literal port number, ResolveUDPAddr resolves the
  65 // address to an address of UDP end point.
  66 // Otherwise, it parses the address as a pair of literal IP address
  67 // and port number.
  68 // The address parameter can use a host name, but this is not
  69 // recommended, because it will return at most one of the host name's
  70 // IP addresses.
  71 //
  72 // See func Dial for a description of the network and address
  73 // parameters.
  74 func ResolveUDPAddr(network, address string) (*UDPAddr, error) {
  75         switch network {
  76         case "udp", "udp4", "udp6":
  77         case "": // a hint wildcard for Go 1.0 undocumented behavior
  78                 network = "udp"
  79         default:
  80                 return nil, UnknownNetworkError(network)
  81         }
  82         addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
  83         if err != nil {
  84                 return nil, err
  85         }
  86         return addrs.forResolve(network, address).(*UDPAddr), nil
  87 }
  88
  89 // UDPConn is the implementation of the Conn and PacketConn interfaces
  90 // for UDP network connections.
  91 type UDPConn struct {
  92         conn
  93 }
  94
  95 // SyscallConn returns a raw network connection.
  96 // This implements the syscall.Conn interface.
  97 func (c *UDPConn) SyscallConn() (syscall.RawConn, error) {
  98         if !c.ok() {
  99                 return nil, syscall.EINVAL
 100         }
 101         return newRawConn(c.fd)
 102 }
 103
 104 // ReadFromUDP acts like ReadFrom but returns a UDPAddr.
 105 func (c *UDPConn) ReadFromUDP(b []byte) (int, *UDPAddr, error) {
 106         if !c.ok() {
 107                 return 0, nil, syscall.EINVAL
 108         }
 109         n, addr, err := c.readFrom(b)
 110         if err != nil {
 111                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 112         }
 113         return n, addr, err
 114 }
 115
 116 // ReadFrom implements the PacketConn ReadFrom method.
 117 func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) {
 118         if !c.ok() {
 119                 return 0, nil, syscall.EINVAL
 120         }
 121         n, addr, err := c.readFrom(b)
 122         if err != nil {
 123                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 124         }
 125         if addr == nil {
 126                 return n, nil, err
 127         }
 128         return n, addr, err
 129 }
 130
 131 // ReadMsgUDP reads a message from c, copying the payload into b and
 132 // the associated out-of-band data into oob. It returns the number of
 133 // bytes copied into b, the number of bytes copied into oob, the flags
 134 // that were set on the message and the source address of the message.
 135 //
 136 // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
 137 // used to manipulate IP-level socket options in oob.
 138 func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
 139         if !c.ok() {
 140                 return 0, 0, 0, nil, syscall.EINVAL
 141         }
 142         n, oobn, flags, addr, err = c.readMsg(b, oob)
 143         if err != nil {
 144                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 145         }
 146         return
 147 }
 148
 149 // WriteToUDP acts like WriteTo but takes a UDPAddr.
 150 func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) {
 151         if !c.ok() {
 152                 return 0, syscall.EINVAL
 153         }
 154         n, err := c.writeTo(b, addr)
 155         if err != nil {
 156                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 157         }
 158         return n, err
 159 }
 160
 161 // WriteTo implements the PacketConn WriteTo method.
 162 func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) {
 163         if !c.ok() {
 164                 return 0, syscall.EINVAL
 165         }
 166         a, ok := addr.(*UDPAddr)
 167         if !ok {
 168                 return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
 169         }
 170         n, err := c.writeTo(b, a)
 171         if err != nil {
 172                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
 173         }
 174         return n, err
 175 }
 176
 177 // WriteMsgUDP writes a message to addr via c if c isn't connected, or
 178 // to c's remote address if c is connected (in which case addr must be
 179 // nil). The payload is copied from b and the associated out-of-band
 180 // data is copied from oob. It returns the number of payload and
 181 // out-of-band bytes written.
 182 //
 183 // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
 184 // used to manipulate IP-level socket options in oob.
 185 func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
 186         if !c.ok() {
 187                 return 0, 0, syscall.EINVAL
 188         }
 189         n, oobn, err = c.writeMsg(b, oob, addr)
 190         if err != nil {
 191                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 192         }
 193         return
 194 }
 195
 196 func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
 197
 198 // DialUDP acts like Dial for UDP networks.
 199 //
 200 // The network must be a UDP network name; see func Dial for details.
 201 //
 202 // If laddr is nil, a local address is automatically chosen.
 203 // If the IP field of raddr is nil or an unspecified IP address, the
 204 // local system is assumed.
 205 func DialUDP(network string, laddr, raddr *UDPAddr) (*UDPConn, error) {
 206         switch network {
 207         case "udp", "udp4", "udp6":
 208         default:
 209                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
 210         }
 211         if raddr == nil {
 212                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
 213         }
 214         sd := &sysDialer{network: network, address: raddr.String()}
 215         c, err := sd.dialUDP(context.Background(), laddr, raddr)
 216         if err != nil {
 217                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 218         }
 219         return c, nil
 220 }
 221
 222 // ListenUDP acts like ListenPacket for UDP networks.
 223 //
 224 // The network must be a UDP network name; see func Dial for details.
 225 //
 226 // If the IP field of laddr is nil or an unspecified IP address,
 227 // ListenUDP listens on all available IP addresses of the local system
 228 // except multicast IP addresses.
 229 // If the Port field of laddr is 0, a port number is automatically
 230 // chosen.
 231 func ListenUDP(network string, laddr *UDPAddr) (*UDPConn, error) {
 232         switch network {
 233         case "udp", "udp4", "udp6":
 234         default:
 235                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)}
 236         }
 237         if laddr == nil {
 238                 laddr = &UDPAddr{}
 239         }
 240         sl := &sysListener{network: network, address: laddr.String()}
 241         c, err := sl.listenUDP(context.Background(), laddr)
 242         if err != nil {
 243                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
 244         }
 245         return c, nil
 246 }
 247
 248 // ListenMulticastUDP acts like ListenPacket for UDP networks but
 249 // takes a group address on a specific network interface.
 250 //
 251 // The network must be a UDP network name; see func Dial for details.
 252 //
 253 // ListenMulticastUDP listens on all available IP addresses of the
 254 // local system including the group, multicast IP address.
 255 // If ifi is nil, ListenMulticastUDP uses the system-assigned
 256 // multicast interface, although this is not recommended because the
 257 // assignment depends on platforms and sometimes it might require
 258 // routing configuration.
 259 // If the Port field of gaddr is 0, a port number is automatically
 260 // chosen.
 261 //
 262 // ListenMulticastUDP is just for convenience of simple, small
 263 // applications. There are golang.org/x/net/ipv4 and
 264 // golang.org/x/net/ipv6 packages for general purpose uses.
 265 func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
 266         switch network {
 267         case "udp", "udp4", "udp6":
 268         default:
 269                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: UnknownNetworkError(network)}
 270         }
 271         if gaddr == nil || gaddr.IP == nil {
 272                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: errMissingAddress}
 273         }
 274         sl := &sysListener{network: network, address: gaddr.String()}
 275         c, err := sl.listenMulticastUDP(context.Background(), ifi, gaddr)
 276         if err != nil {
 277                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: err}
 278         }
 279         return c, nil
 280 }