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Commit 20de705b authored by Mikio Hara's avatar Mikio Hara
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net: deduplicate UDP socket code 

This change consolidates functions and methods related to UDPAddr and
UDPConn for maintenance purpose, especially for documentation.

The followup changes will update comments and examples.

Updates #10624.

Change-Id: Idfe9be8ea46ade1111b0ae176862b2048eafc7be
Reviewed-on: https://go-review.googlesource.com/20120
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: 's avatarIan Lance Taylor <iant@golang.org>
parent 1f96c83b
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Inline Side-by-side
Showing with 216 additions and 277 deletions
src/net/udpsock.go
View file @ 20de705b
......@@ -4,6 +4,8 @@
package net
import "syscall"
// UDPAddr represents the address of a UDP end point.
type UDPAddr struct {
IP IP
......@@ -59,3 +61,179 @@ func ResolveUDPAddr(net, addr string) (*UDPAddr, error) {
}
return addrs.first(isIPv4).(*UDPAddr), nil
}
// UDPConn is the implementation of the Conn and PacketConn interfaces
// for UDP network connections.
type UDPConn struct {
conn
}
// 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) (int, *UDPAddr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
n, addr, err := c.readFrom(b)
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
return n, addr, err
}
// 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.readFrom(b)
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
if addr == nil {
return n, nil, err
}
return n, addr, err
}
// ReadMsgUDP reads a packet from c, copying the payload into b and
// the associated 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
}
n, oobn, flags, addr, err = c.readMsg(b, oob)
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
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
}
n, err := c.writeTo(b, addr)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
}
return n, err
}
// 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{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
}
n, err := c.writeTo(b, a)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
}
return n, err
}
// WriteMsgUDP writes a packet to addr via c if c isn't connected, or
// to c's remote destination address if c is connected (in which case
// addr must be nil). The payload is copied from b and the associated
// out-of-band data is copied 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
}
n, oobn, err = c.writeMsg(b, oob, addr)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
}
return
}
func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
// 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) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(net)}
}
if raddr == nil {
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
}
c, err := dialUDP(net, laddr, raddr, noDeadline)
if err != nil {
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
}
return c, nil
}
// ListenUDP listens for incoming UDP packets addressed to the local
// address laddr. Net must be "udp", "udp4", or "udp6". If laddr has
// a port of 0, ListenUDP will choose an available port.
// The LocalAddr method of the returned UDPConn can be used to
// discover the port. The returned connection'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, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)}
}
if laddr == nil {
laddr = &UDPAddr{}
}
c, err := listenUDP(net, laddr)
if err != nil {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: err}
}
return c, nil
}
// ListenMulticastUDP listens for incoming multicast UDP packets
// addressed to the group address gaddr on the interface ifi.
// Network must be "udp", "udp4" or "udp6".
// ListenMulticastUDP uses the system-assigned multicast interface
// when ifi is nil, although this is not recommended because the
// assignment depends on platforms and sometimes it might require
// routing configuration.
//
// ListenMulticastUDP is just for convenience of simple, small
// applications. There are golang.org/x/net/ipv4 and
// golang.org/x/net/ipv6 packages for general purpose uses.
func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
switch network {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: UnknownNetworkError(network)}
}
if gaddr == nil || gaddr.IP == nil {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: errMissingAddress}
}
c, err := listenMulticastUDP(network, ifi, gaddr)
if err != nil {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: err}
}
return c, nil
}
src/net/udpsock_plan9.go
View file @ 20de705b
......@@ -11,32 +11,14 @@ import (
"time"
)
// 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() || c.fd.data == nil {
return 0, nil, syscall.EINVAL
}
func (c *UDPConn) readFrom(b []byte) (n int, addr *UDPAddr, err error) {
buf := make([]byte, udpHeaderSize+len(b))
m, err := c.fd.data.Read(buf)
m, err := c.fd.Read(buf)
if err != nil {
return 0, nil, &OpError{Op: "read", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
return 0, nil, err
}
if m < udpHeaderSize {
return 0, nil, &OpError{Op: "read", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: errors.New("short read reading UDP header")}
return 0, nil, errors.New("short read reading UDP header")
}
buf = buf[:m]
......@@ -45,36 +27,13 @@ func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err error) {
return n, &UDPAddr{IP: h.raddr, Port: int(h.rport)}, nil
}
// ReadFrom implements the PacketConn ReadFrom method.
func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
return c.ReadFromUDP(b)
func (c *UDPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
return 0, 0, 0, nil, syscall.EPLAN9
}
// ReadMsgUDP reads a packet from c, copying the payload into b and
// the associated 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) {
return 0, 0, 0, nil, &OpError{Op: "read", Net: c.fd.dir, Source: c.fd.laddr, Addr: c.fd.raddr, Err: syscall.EPLAN9}
}
// 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() || c.fd.data == nil {
return 0, syscall.EINVAL
}
func (c *UDPConn) writeTo(b []byte, addr *UDPAddr) (int, error) {
if addr == nil {
return 0, &OpError{Op: "write", Net: c.fd.dir, Source: c.fd.laddr, Addr: nil, Err: errMissingAddress}
return 0, errMissingAddress
}
h := new(udpHeader)
h.raddr = addr.IP.To16()
......@@ -86,56 +45,20 @@ func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) {
buf := make([]byte, udpHeaderSize+len(b))
i := copy(buf, h.Bytes())
copy(buf[i:], b)
if _, err := c.fd.data.Write(buf); err != nil {
return 0, &OpError{Op: "write", Net: c.fd.dir, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
if _, err := c.fd.Write(buf); err != nil {
return 0, err
}
return len(b), nil
}
// 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{Op: "write", Net: c.fd.dir, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
}
return c.WriteToUDP(b, a)
}
// WriteMsgUDP writes a packet to addr via c if c isn't connected, or
// to c's remote destination address if c is connected (in which case
// addr must be nil). The payload is copied from b and the associated
// out-of-band data is copied 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) {
return 0, 0, &OpError{Op: "write", Net: c.fd.dir, Source: c.fd.laddr, Addr: addr.opAddr(), Err: syscall.EPLAN9}
}
// 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) {
c, err := dialUDP(net, laddr, raddr, noDeadline)
if err != nil {
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
}
return c, nil
func (c *UDPConn) writeMsg(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
return 0, 0, syscall.EPLAN9
}
func dialUDP(net string, laddr, raddr *UDPAddr, deadline time.Time) (*UDPConn, error) {
if !deadline.IsZero() {
panic("net.dialUDP: deadline not implemented on Plan 9")
}
switch net {
case "udp", "udp4", "udp6":
default:
return nil, UnknownNetworkError(net)
}
if raddr == nil {
return nil, errMissingAddress
}
fd, err := dialPlan9(net, laddr, raddr)
if err != nil {
return nil, err
......@@ -171,49 +94,23 @@ func unmarshalUDPHeader(b []byte) (*udpHeader, []byte) {
return h, b
}
// ListenUDP listens for incoming UDP packets addressed to the local
// address laddr. Net must be "udp", "udp4", or "udp6". If laddr has
// a port of 0, ListenUDP will choose an available port.
// The LocalAddr method of the returned UDPConn can be used to
// discover the port. The returned connection'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, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)}
}
if laddr == nil {
laddr = &UDPAddr{}
}
l, err := listenPlan9(net, laddr)
func listenUDP(network string, laddr *UDPAddr) (*UDPConn, error) {
l, err := listenPlan9(network, laddr)
if err != nil {
return nil, err
}
_, err = l.ctl.WriteString("headers")
if err != nil {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr, Err: err}
return nil, err
}
l.data, err = os.OpenFile(l.dir+"/data", os.O_RDWR, 0)
if err != nil {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr, Err: err}
return nil, err
}
fd, err := l.netFD()
return newUDPConn(fd), err
}
// ListenMulticastUDP listens for incoming multicast UDP packets
// addressed to the group address gaddr on the interface ifi.
// Network must be "udp", "udp4" or "udp6".
// ListenMulticastUDP uses the system-assigned multicast interface
// when ifi is nil, although this is not recommended because the
// assignment depends on platforms and sometimes it might require
// routing configuration.
//
// ListenMulticastUDP is just for convenience of simple, small
// applications. There are golang.org/x/net/ipv4 and
// golang.org/x/net/ipv6 packages for general purpose uses.
func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: syscall.EPLAN9}
func listenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
return nil, syscall.EPLAN9
}
src/net/udpsock_posix.go
View file @ 20de705b
......@@ -38,25 +38,7 @@ func (a *UDPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
return ipToSockaddr(family, a.IP, a.Port, a.Zone)
}
// 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) (int, *UDPAddr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
func (c *UDPConn) readFrom(b []byte) (int, *UDPAddr, error) {
var addr *UDPAddr
n, sa, err := c.fd.readFrom(b)
switch sa := sa.(type) {
......@@ -65,33 +47,10 @@ func (c *UDPConn) ReadFromUDP(b []byte) (int, *UDPAddr, error) {
case *syscall.SockaddrInet6:
addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
}
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
return n, addr, err
}
// 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)
if addr == nil {
return n, nil, err
}
return n, addr, err
}
// ReadMsgUDP reads a packet from c, copying the payload into b and
// the associated 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
}
func (c *UDPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
var sa syscall.Sockaddr
n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
switch sa := sa.(type) {
......@@ -100,96 +59,35 @@ func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr,
case *syscall.SockaddrInet6:
addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
}
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
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
}
func (c *UDPConn) writeTo(b []byte, addr *UDPAddr) (int, error) {
if c.fd.isConnected {
return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: ErrWriteToConnected}
return 0, ErrWriteToConnected
}
if addr == nil {
return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: nil, Err: errMissingAddress}
return 0, errMissingAddress
}
sa, err := addr.sockaddr(c.fd.family)
if err != nil {
return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
return 0, err
}
n, err := c.fd.writeTo(b, sa)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
}
return n, 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{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
}
return c.WriteToUDP(b, a)
}
// WriteMsgUDP writes a packet to addr via c if c isn't connected, or
// to c's remote destination address if c is connected (in which case
// addr must be nil). The payload is copied from b and the associated
// out-of-band data is copied 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
}
func (c *UDPConn) writeMsg(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
if c.fd.isConnected && addr != nil {
return 0, 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: ErrWriteToConnected}
return 0, 0, ErrWriteToConnected
}
if !c.fd.isConnected && addr == nil {
return 0, 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: errMissingAddress}
}
var sa syscall.Sockaddr
sa, err = addr.sockaddr(c.fd.family)
if err != nil {
return 0, 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
}
n, oobn, err = c.fd.writeMsg(b, oob, sa)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
}
return
}
// 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) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(net)}
}
if raddr == nil {
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
return 0, 0, errMissingAddress
}
c, err := dialUDP(net, laddr, raddr, noDeadline)
sa, err := addr.sockaddr(c.fd.family)
if err != nil {
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
return 0, 0, err
}
return c, nil
return c.fd.writeMsg(b, oob, sa)
}
func dialUDP(net string, laddr, raddr *UDPAddr, deadline time.Time) (*UDPConn, error) {
......@@ -200,63 +98,29 @@ func dialUDP(net string, laddr, raddr *UDPAddr, deadline time.Time) (*UDPConn, e
return newUDPConn(fd), nil
}
// ListenUDP listens for incoming UDP packets addressed to the local
// address laddr. Net must be "udp", "udp4", or "udp6". If laddr has
// a port of 0, ListenUDP will choose an available port.
// The LocalAddr method of the returned UDPConn can be used to
// discover the port. The returned connection'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, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)}
}
if laddr == nil {
laddr = &UDPAddr{}
}
fd, err := internetSocket(net, laddr, nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", noCancel)
func listenUDP(network string, laddr *UDPAddr) (*UDPConn, error) {
fd, err := internetSocket(network, laddr, nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", noCancel)
if err != nil {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr, Err: err}
return nil, err
}
return newUDPConn(fd), nil
}
// ListenMulticastUDP listens for incoming multicast UDP packets
// addressed to the group address gaddr on the interface ifi.
// Network must be "udp", "udp4" or "udp6".
// ListenMulticastUDP uses the system-assigned multicast interface
// when ifi is nil, although this is not recommended because the
// assignment depends on platforms and sometimes it might require
// routing configuration.
//
// ListenMulticastUDP is just for convenience of simple, small
// applications. There are golang.org/x/net/ipv4 and
// golang.org/x/net/ipv6 packages for general purpose uses.
func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
switch network {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: UnknownNetworkError(network)}
}
if gaddr == nil || gaddr.IP == nil {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: errMissingAddress}
}
func listenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
fd, err := internetSocket(network, gaddr, nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", noCancel)
if err != nil {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr, Err: err}
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{Op: "listen", Net: network, Source: c.fd.laddr, Addr: &IPAddr{IP: ip4}, Err: err}
return nil, err
}
} else {
if err := listenIPv6MulticastUDP(c, ifi, gaddr.IP); err != nil {
c.Close()
return nil, &OpError{Op: "listen", Net: network, Source: c.fd.laddr, Addr: &IPAddr{IP: gaddr.IP}, Err: err}
return nil, err
}
}
return c, nil
......
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