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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// UDP sockets
package net
import (
"os"
"syscall"
)
func sockaddrToUDP(sa syscall.Sockaddr) Addr {
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
return &UDPAddr{sa.Addr[0:], sa.Port}
case *syscall.SockaddrInet6:
return &UDPAddr{sa.Addr[0:], sa.Port}
}
return nil
}
// UDPAddr represents the address of a UDP end point.
type UDPAddr struct {
IP IP
Port int
}
// Network returns the address's network name, "udp".
func (a *UDPAddr) Network() string { return "udp" }
func (a *UDPAddr) String() string {
if a == nil {
return "<nil>"
}
return joinHostPort(a.IP.String(), itoa(a.Port))
}
func (a *UDPAddr) family() int {
if a == nil || len(a.IP) <= 4 {
return syscall.AF_INET
}
if ip := a.IP.To4(); ip != nil {
return syscall.AF_INET
}
return syscall.AF_INET6
}
func (a *UDPAddr) sockaddr(family int) (syscall.Sockaddr, os.Error) {
return ipToSockaddr(family, a.IP, a.Port)
}
func (a *UDPAddr) toAddr() sockaddr {
if a == nil { // nil *UDPAddr
return nil // nil interface
}
return a
}
// ResolveUDPAddr parses addr as a UDP address of the form
// host:port and resolves domain names or port names to
// numeric addresses. A literal IPv6 host address must be
// enclosed in square brackets, as in "[::]:80".
func ResolveUDPAddr(addr string) (*UDPAddr, os.Error) {
ip, port, err := hostPortToIP("udp", addr)
if err != nil {
return nil, err
}
return &UDPAddr{ip, port}, nil
}
// UDPConn is the implementation of the Conn and PacketConn
// interfaces for UDP network connections.
type UDPConn struct {
fd *netFD
}
func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{fd} }
func (c *UDPConn) ok() bool { return c != nil && c.fd != nil }
// Implementation of the Conn interface - see Conn for documentation.
// Read implements the net.Conn Read method.
func (c *UDPConn) Read(b []byte) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
return c.fd.Read(b)
}
// Write implements the net.Conn Write method.
func (c *UDPConn) Write(b []byte) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
return c.fd.Write(b)
}
// Close closes the UDP connection.
func (c *UDPConn) Close() os.Error {
if !c.ok() {
return os.EINVAL
}
err := c.fd.Close()
c.fd = nil
return err
}
// LocalAddr returns the local network address.
func (c *UDPConn) LocalAddr() Addr {
if !c.ok() {
return nil
}
return c.fd.laddr
}
// RemoteAddr returns the remote network address, a *UDPAddr.
func (c *UDPConn) RemoteAddr() Addr {
if !c.ok() {
return nil
}
return c.fd.raddr
}
// SetTimeout implements the net.Conn SetTimeout method.
func (c *UDPConn) SetTimeout(nsec int64) os.Error {
if !c.ok() {
return os.EINVAL
}
return setTimeout(c.fd, nsec)
}
// SetReadTimeout implements the net.Conn SetReadTimeout method.
func (c *UDPConn) SetReadTimeout(nsec int64) os.Error {
if !c.ok() {
return os.EINVAL
}
return setReadTimeout(c.fd, nsec)
}
// SetWriteTimeout implements the net.Conn SetWriteTimeout method.
func (c *UDPConn) SetWriteTimeout(nsec int64) os.Error {
if !c.ok() {
return os.EINVAL
}
return setWriteTimeout(c.fd, nsec)
}
// SetReadBuffer sets the size of the operating system's
// receive buffer associated with the connection.
func (c *UDPConn) SetReadBuffer(bytes int) os.Error {
if !c.ok() {
return os.EINVAL
}
return setReadBuffer(c.fd, bytes)
}
// SetWriteBuffer sets the size of the operating system's
// transmit buffer associated with the connection.
func (c *UDPConn) SetWriteBuffer(bytes int) os.Error {
if !c.ok() {
return os.EINVAL
}
return setWriteBuffer(c.fd, bytes)
}
// UDP-specific methods.
// ReadFromUDP reads a UDP packet from c, copying the payload into b.
// It returns the number of bytes copied into b and the return address
// that was on the packet.
//
// ReadFromUDP can be made to time out and return an error with Timeout() == true
// after a fixed time limit; see SetTimeout and SetReadTimeout.
func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err os.Error) {
if !c.ok() {
return 0, nil, os.EINVAL
}
n, sa, err := c.fd.ReadFrom(b)
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
addr = &UDPAddr{sa.Addr[0:], sa.Port}
case *syscall.SockaddrInet6:
addr = &UDPAddr{sa.Addr[0:], sa.Port}
}
return
}
// ReadFrom implements the net.PacketConn ReadFrom method.
func (c *UDPConn) ReadFrom(b []byte) (n int, addr Addr, err os.Error) {
if !c.ok() {
return 0, nil, os.EINVAL
}
n, uaddr, err := c.ReadFromUDP(b)
return n, uaddr.toAddr(), err
}
// WriteToUDP writes a UDP packet to addr via c, copying the payload from b.
//
// WriteToUDP can be made to time out and return
// an error with Timeout() == true after a fixed time limit;
// see SetTimeout and SetWriteTimeout.
// On packet-oriented connections, write timeouts are rare.
func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
sa, err1 := addr.sockaddr(c.fd.family)
if err1 != nil {
return 0, &OpError{Op: "write", Net: "udp", Addr: addr, Error: err1}
}
return c.fd.WriteTo(b, sa)
}
// WriteTo implements the net.PacketConn WriteTo method.
func (c *UDPConn) WriteTo(b []byte, addr Addr) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
a, ok := addr.(*UDPAddr)
if !ok {
return 0, &OpError{"writeto", "udp", addr, os.EINVAL}
}
return c.WriteToUDP(b, a)
}
// DialUDP connects to the remote address raddr on the network net,
// which must be "udp", "udp4", or "udp6". If laddr is not nil, it is used
// as the local address for the connection.
func DialUDP(net string, laddr, raddr *UDPAddr) (c *UDPConn, err os.Error) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, UnknownNetworkError(net)
}
if raddr == nil {
return nil, &OpError{"dial", "udp", nil, errMissingAddress}
}
fd, e := internetSocket(net, laddr.toAddr(), raddr.toAddr(), syscall.SOCK_DGRAM, 0, "dial", sockaddrToUDP)
if e != nil {
return nil, e
}
return newUDPConn(fd), nil
}
// ListenUDP listens for incoming UDP packets addressed to the
// local address laddr. The returned connection c's ReadFrom
// and WriteTo methods can be used to receive and send UDP
// packets with per-packet addressing.
func ListenUDP(net string, laddr *UDPAddr) (c *UDPConn, err os.Error) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, UnknownNetworkError(net)
}
if laddr == nil {
return nil, &OpError{"listen", "udp", nil, errMissingAddress}
}
fd, e := internetSocket(net, laddr.toAddr(), nil, syscall.SOCK_DGRAM, 0, "dial", sockaddrToUDP)
if e != nil {
return nil, e
}
return newUDPConn(fd), nil
}
// BindToDevice binds a UDPConn to a network interface.
func (c *UDPConn) BindToDevice(device string) os.Error {
if !c.ok() {
return os.EINVAL
}
c.fd.incref()
defer c.fd.decref()
return os.NewSyscallError("setsockopt", syscall.BindToDevice(c.fd.sysfd, device))
}
// File returns a copy of the underlying os.File, set to blocking mode.
// It is the caller's responsibility to close f when finished.
// Closing c does not affect f, and closing f does not affect c.
func (c *UDPConn) File() (f *os.File, err os.Error) { return c.fd.dup() }