323 lines
8.4 KiB
Go
323 lines
8.4 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// UDP sockets
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package net
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import (
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"os"
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"syscall"
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)
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func sockaddrToUDP(sa syscall.Sockaddr) Addr {
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switch sa := sa.(type) {
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case *syscall.SockaddrInet4:
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return &UDPAddr{sa.Addr[0:], sa.Port}
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case *syscall.SockaddrInet6:
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return &UDPAddr{sa.Addr[0:], sa.Port}
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}
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return nil
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}
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// UDPAddr represents the address of a UDP end point.
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type UDPAddr struct {
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IP IP
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Port int
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}
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// Network returns the address's network name, "udp".
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func (a *UDPAddr) Network() string { return "udp" }
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func (a *UDPAddr) String() string {
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if a == nil {
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return "<nil>"
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}
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return JoinHostPort(a.IP.String(), itoa(a.Port))
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}
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func (a *UDPAddr) family() int {
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if a == nil || len(a.IP) <= 4 {
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return syscall.AF_INET
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}
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if ip := a.IP.To4(); ip != nil {
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return syscall.AF_INET
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}
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return syscall.AF_INET6
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}
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func (a *UDPAddr) sockaddr(family int) (syscall.Sockaddr, os.Error) {
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return ipToSockaddr(family, a.IP, a.Port)
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}
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func (a *UDPAddr) toAddr() sockaddr {
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if a == nil { // nil *UDPAddr
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return nil // nil interface
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}
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return a
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}
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// ResolveUDPAddr parses addr as a UDP address of the form
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// host:port and resolves domain names or port names to
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// numeric addresses. A literal IPv6 host address must be
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// enclosed in square brackets, as in "[::]:80".
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func ResolveUDPAddr(network, addr string) (*UDPAddr, os.Error) {
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ip, port, err := hostPortToIP(network, addr)
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if err != nil {
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return nil, err
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}
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return &UDPAddr{ip, port}, nil
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}
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// UDPConn is the implementation of the Conn and PacketConn
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// interfaces for UDP network connections.
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type UDPConn struct {
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fd *netFD
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}
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func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{fd} }
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func (c *UDPConn) ok() bool { return c != nil && c.fd != nil }
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// Implementation of the Conn interface - see Conn for documentation.
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// Read implements the net.Conn Read method.
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func (c *UDPConn) Read(b []byte) (n int, err os.Error) {
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if !c.ok() {
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return 0, os.EINVAL
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}
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return c.fd.Read(b)
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}
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// Write implements the net.Conn Write method.
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func (c *UDPConn) Write(b []byte) (n int, err os.Error) {
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if !c.ok() {
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return 0, os.EINVAL
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}
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return c.fd.Write(b)
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}
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// Close closes the UDP connection.
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func (c *UDPConn) Close() os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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err := c.fd.Close()
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c.fd = nil
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return err
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}
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// LocalAddr returns the local network address.
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func (c *UDPConn) LocalAddr() Addr {
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if !c.ok() {
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return nil
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}
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return c.fd.laddr
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}
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// RemoteAddr returns the remote network address, a *UDPAddr.
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func (c *UDPConn) RemoteAddr() Addr {
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if !c.ok() {
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return nil
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}
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return c.fd.raddr
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}
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// SetTimeout implements the net.Conn SetTimeout method.
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func (c *UDPConn) SetTimeout(nsec int64) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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return setTimeout(c.fd, nsec)
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}
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// SetReadTimeout implements the net.Conn SetReadTimeout method.
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func (c *UDPConn) SetReadTimeout(nsec int64) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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return setReadTimeout(c.fd, nsec)
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}
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// SetWriteTimeout implements the net.Conn SetWriteTimeout method.
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func (c *UDPConn) SetWriteTimeout(nsec int64) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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return setWriteTimeout(c.fd, nsec)
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}
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// SetReadBuffer sets the size of the operating system's
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// receive buffer associated with the connection.
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func (c *UDPConn) SetReadBuffer(bytes int) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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return setReadBuffer(c.fd, bytes)
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}
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// SetWriteBuffer sets the size of the operating system's
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// transmit buffer associated with the connection.
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func (c *UDPConn) SetWriteBuffer(bytes int) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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return setWriteBuffer(c.fd, bytes)
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}
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// UDP-specific methods.
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// ReadFromUDP reads a UDP packet from c, copying the payload into b.
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// It returns the number of bytes copied into b and the return address
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// that was on the packet.
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//
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// ReadFromUDP can be made to time out and return an error with Timeout() == true
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// after a fixed time limit; see SetTimeout and SetReadTimeout.
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func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err os.Error) {
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if !c.ok() {
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return 0, nil, os.EINVAL
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}
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n, sa, err := c.fd.ReadFrom(b)
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switch sa := sa.(type) {
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case *syscall.SockaddrInet4:
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addr = &UDPAddr{sa.Addr[0:], sa.Port}
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case *syscall.SockaddrInet6:
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addr = &UDPAddr{sa.Addr[0:], sa.Port}
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}
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return
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}
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// ReadFrom implements the net.PacketConn ReadFrom method.
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func (c *UDPConn) ReadFrom(b []byte) (n int, addr Addr, err os.Error) {
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if !c.ok() {
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return 0, nil, os.EINVAL
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}
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n, uaddr, err := c.ReadFromUDP(b)
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return n, uaddr.toAddr(), err
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}
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// WriteToUDP writes a UDP packet to addr via c, copying the payload from b.
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//
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// WriteToUDP can be made to time out and return
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// an error with Timeout() == true after a fixed time limit;
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// see SetTimeout and SetWriteTimeout.
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// On packet-oriented connections, write timeouts are rare.
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func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (n int, err os.Error) {
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if !c.ok() {
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return 0, os.EINVAL
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}
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sa, err1 := addr.sockaddr(c.fd.family)
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if err1 != nil {
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return 0, &OpError{Op: "write", Net: "udp", Addr: addr, Error: err1}
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}
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return c.fd.WriteTo(b, sa)
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}
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// WriteTo implements the net.PacketConn WriteTo method.
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func (c *UDPConn) WriteTo(b []byte, addr Addr) (n int, err os.Error) {
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if !c.ok() {
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return 0, os.EINVAL
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}
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a, ok := addr.(*UDPAddr)
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if !ok {
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return 0, &OpError{"writeto", "udp", addr, os.EINVAL}
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}
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return c.WriteToUDP(b, a)
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}
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// DialUDP connects to the remote address raddr on the network net,
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// which must be "udp", "udp4", or "udp6". If laddr is not nil, it is used
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// as the local address for the connection.
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func DialUDP(net string, laddr, raddr *UDPAddr) (c *UDPConn, err os.Error) {
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switch net {
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case "udp", "udp4", "udp6":
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default:
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return nil, UnknownNetworkError(net)
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}
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if raddr == nil {
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return nil, &OpError{"dial", "udp", nil, errMissingAddress}
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}
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fd, e := internetSocket(net, laddr.toAddr(), raddr.toAddr(), syscall.SOCK_DGRAM, 0, "dial", sockaddrToUDP)
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if e != nil {
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return nil, e
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}
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return newUDPConn(fd), nil
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}
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// ListenUDP listens for incoming UDP packets addressed to the
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// local address laddr. The returned connection c's ReadFrom
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// and WriteTo methods can be used to receive and send UDP
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// packets with per-packet addressing.
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func ListenUDP(net string, laddr *UDPAddr) (c *UDPConn, err os.Error) {
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switch net {
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case "udp", "udp4", "udp6":
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default:
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return nil, UnknownNetworkError(net)
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}
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if laddr == nil {
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return nil, &OpError{"listen", "udp", nil, errMissingAddress}
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}
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fd, e := internetSocket(net, laddr.toAddr(), nil, syscall.SOCK_DGRAM, 0, "dial", sockaddrToUDP)
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if e != nil {
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return nil, e
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}
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return newUDPConn(fd), nil
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}
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// BindToDevice binds a UDPConn to a network interface.
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func (c *UDPConn) BindToDevice(device string) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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c.fd.incref()
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defer c.fd.decref()
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return os.NewSyscallError("setsockopt", syscall.BindToDevice(c.fd.sysfd, device))
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}
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// File returns a copy of the underlying os.File, set to blocking mode.
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// It is the caller's responsibility to close f when finished.
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// Closing c does not affect f, and closing f does not affect c.
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func (c *UDPConn) File() (f *os.File, err os.Error) { return c.fd.dup() }
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var errInvalidMulticast = os.ErrorString("invalid IPv4 multicast address")
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// JoinGroup joins the IPv4 multicast group named by addr.
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// The UDPConn must use the "udp4" network.
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func (c *UDPConn) JoinGroup(addr IP) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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ip := addr.To4()
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if ip == nil {
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return &OpError{"joingroup", "udp", &IPAddr{ip}, errInvalidMulticast}
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}
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mreq := &syscall.IpMreq{
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Multiaddr: [4]byte{ip[0], ip[1], ip[2], ip[3]},
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}
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err := os.NewSyscallError("setsockopt", syscall.SetsockoptIpMreq(c.fd.sysfd, syscall.IPPROTO_IP, syscall.IP_ADD_MEMBERSHIP, mreq))
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if err != nil {
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return &OpError{"joingroup", "udp", &IPAddr{ip}, err}
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}
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return nil
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}
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// LeaveGroup exits the IPv4 multicast group named by addr.
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func (c *UDPConn) LeaveGroup(addr IP) os.Error {
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if !c.ok() {
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return os.EINVAL
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}
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ip := addr.To4()
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if ip == nil {
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return &OpError{"leavegroup", "udp", &IPAddr{ip}, errInvalidMulticast}
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}
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mreq := &syscall.IpMreq{
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Multiaddr: [4]byte{ip[0], ip[1], ip[2], ip[3]},
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}
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err := os.NewSyscallError("setsockopt", syscall.SetsockoptIpMreq(c.fd.sysfd, syscall.IPPROTO_IP, syscall.IP_DROP_MEMBERSHIP, mreq))
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if err != nil {
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return &OpError{"leavegroup", "udp", &IPAddr{ip}, err}
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}
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return nil
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}
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