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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.
// +build darwin freebsd linux netbsd openbsd windows
// UDP sockets for POSIX
package net
import (
"syscall"
"time"
)
func sockaddrToUDP(sa syscall.Sockaddr) Addr {
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
return &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
case *syscall.SockaddrInet6:
return &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
}
return nil
}
func (a *UDPAddr) family() int {
if a == nil || len(a.IP) <= IPv4len {
return syscall.AF_INET
}
if a.IP.To4() != nil {
return syscall.AF_INET
}
return syscall.AF_INET6
}
func (a *UDPAddr) isWildcard() bool {
if a == nil || a.IP == nil {
return true
}
return a.IP.IsUnspecified()
}
func (a *UDPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
return ipToSockaddr(family, a.IP, a.Port, a.Zone)
}
func (a *UDPAddr) toAddr() sockaddr {
if a == nil { // nil *UDPAddr
return nil // nil interface
}
return a
}
// UDPConn is the implementation of the Conn and PacketConn
// interfaces for UDP network connections.
type UDPConn struct {
conn
}
func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
// 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 SetDeadline and SetReadDeadline.
func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
n, sa, err := c.fd.ReadFrom(b)
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
case *syscall.SockaddrInet6:
addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
}
return
}
// ReadFrom implements the PacketConn ReadFrom method.
func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
n, addr, err := c.ReadFromUDP(b)
return n, addr.toAddr(), err
}
// ReadMsgUDP reads a packet from c, copying the payload into b and
// the associdated out-of-band data into oob. It returns the number
// of bytes copied into b, the number of bytes copied into oob, the
// flags that were set on the packet and the source address of the
// packet.
func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
if !c.ok() {
return 0, 0, 0, nil, syscall.EINVAL
}
var sa syscall.Sockaddr
n, oobn, flags, sa, err = c.fd.ReadMsg(b, oob)
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
case *syscall.SockaddrInet6:
addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
}
return
}
// 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 SetDeadline and SetWriteDeadline.
// On packet-oriented connections, write timeouts are rare.
func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) {
if !c.ok() {
return 0, syscall.EINVAL
}
if c.fd.isConnected {
return 0, &OpError{"write", c.fd.net, addr, ErrWriteToConnected}
}
sa, err := addr.sockaddr(c.fd.family)
if err != nil {
return 0, &OpError{"write", c.fd.net, addr, err}
}
return c.fd.WriteTo(b, sa)
}
// WriteTo implements the PacketConn WriteTo method.
func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) {
if !c.ok() {
return 0, syscall.EINVAL
}
a, ok := addr.(*UDPAddr)
if !ok {
return 0, &OpError{"write", c.fd.net, addr, syscall.EINVAL}
}
return c.WriteToUDP(b, a)
}
// WriteMsgUDP writes a packet to addr via c, copying the payload from
// b and the associated out-of-band data from oob. It returns the
// number of payload and out-of-band bytes written.
func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
if !c.ok() {
return 0, 0, syscall.EINVAL
}
if c.fd.isConnected {
return 0, 0, &OpError{"write", c.fd.net, addr, ErrWriteToConnected}
}
sa, err := addr.sockaddr(c.fd.family)
if err != nil {
return 0, 0, &OpError{"write", c.fd.net, addr, err}
}
return c.fd.WriteMsg(b, oob, sa)
}
// 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) (*UDPConn, error) {
return dialUDP(net, laddr, raddr, noDeadline)
}
func dialUDP(net string, laddr, raddr *UDPAddr, deadline time.Time) (*UDPConn, error) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, UnknownNetworkError(net)
}
if raddr == nil {
return nil, &OpError{"dial", net, nil, errMissingAddress}
}
fd, err := internetSocket(net, laddr.toAddr(), raddr.toAddr(), deadline, syscall.SOCK_DGRAM, 0, "dial", sockaddrToUDP)
if err != nil {
return nil, err
}
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) (*UDPConn, error) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, UnknownNetworkError(net)
}
if laddr == nil {
laddr = &UDPAddr{}
}
fd, err := internetSocket(net, laddr.toAddr(), nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", sockaddrToUDP)
if err != nil {
return nil, err
}
return newUDPConn(fd), nil
}
// ListenMulticastUDP listens for incoming multicast UDP packets
// addressed to the group address gaddr on ifi, which specifies
// the interface to join. ListenMulticastUDP uses default
// multicast interface if ifi is nil.
func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, UnknownNetworkError(net)
}
if gaddr == nil || gaddr.IP == nil {
return nil, &OpError{"listen", net, nil, errMissingAddress}
}
fd, err := internetSocket(net, gaddr.toAddr(), nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", sockaddrToUDP)
if err != nil {
return nil, err
}
c := newUDPConn(fd)
if ip4 := gaddr.IP.To4(); ip4 != nil {
if err := listenIPv4MulticastUDP(c, ifi, ip4); err != nil {
c.Close()
return nil, &OpError{"listen", net, &IPAddr{IP: ip4}, err}
}
} else {
if err := listenIPv6MulticastUDP(c, ifi, gaddr.IP); err != nil {
c.Close()
return nil, &OpError{"listen", net, &IPAddr{IP: gaddr.IP}, err}
}
}
return c, nil
}
func listenIPv4MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
if ifi != nil {
if err := setIPv4MulticastInterface(c.fd, ifi); err != nil {
return err
}
}
if err := setIPv4MulticastLoopback(c.fd, false); err != nil {
return err
}
if err := joinIPv4Group(c.fd, ifi, ip); err != nil {
return err
}
return nil
}
func listenIPv6MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
if ifi != nil {
if err := setIPv6MulticastInterface(c.fd, ifi); err != nil {
return err
}
}
if err := setIPv6MulticastLoopback(c.fd, false); err != nil {
return err
}
if err := joinIPv6Group(c.fd, ifi, ip); err != nil {
return err
}
return nil
}
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