| // 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() } |