275 lines
8.5 KiB
Go
275 lines
8.5 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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package net
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import (
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"context"
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"syscall"
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)
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// BUG(mikio): On NaCl, Plan 9 and Windows, the ReadMsgUDP and
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// WriteMsgUDP methods of UDPConn are not implemented.
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// BUG(mikio): On Windows, the File method of UDPConn is not
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// implemented.
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// BUG(mikio): On NaCl, the ListenMulticastUDP function is not
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// implemented.
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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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Zone string // IPv6 scoped addressing zone
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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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ip := ipEmptyString(a.IP)
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if a.Zone != "" {
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return JoinHostPort(ip+"%"+a.Zone, itoa(a.Port))
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}
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return JoinHostPort(ip, itoa(a.Port))
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}
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func (a *UDPAddr) isWildcard() bool {
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if a == nil || a.IP == nil {
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return true
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}
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return a.IP.IsUnspecified()
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}
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func (a *UDPAddr) opAddr() Addr {
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if a == nil {
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return nil
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}
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return a
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}
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// ResolveUDPAddr returns an address of UDP end point.
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//
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// The network must be a UDP network name.
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//
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// If the host in the address parameter is not a literal IP address or
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// the port is not a literal port number, ResolveUDPAddr resolves the
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// address to an address of UDP end point.
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// Otherwise, it parses the address as a pair of literal IP address
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// and port number.
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// The address parameter can use a host name, but this is not
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// recommended, because it will return at most one of the host name's
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// IP addresses.
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//
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// See func Dial for a description of the network and address
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// parameters.
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func ResolveUDPAddr(network, address string) (*UDPAddr, error) {
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switch network {
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case "udp", "udp4", "udp6":
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case "": // a hint wildcard for Go 1.0 undocumented behavior
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network = "udp"
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default:
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return nil, UnknownNetworkError(network)
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}
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addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
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if err != nil {
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return nil, err
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}
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return addrs.forResolve(network, address).(*UDPAddr), nil
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}
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// UDPConn is the implementation of the Conn and PacketConn interfaces
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// for UDP network connections.
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type UDPConn struct {
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conn
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}
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// SyscallConn returns a raw network connection.
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// This implements the syscall.Conn interface.
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func (c *UDPConn) SyscallConn() (syscall.RawConn, error) {
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if !c.ok() {
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return nil, syscall.EINVAL
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}
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return newRawConn(c.fd)
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}
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// ReadFromUDP acts like ReadFrom but returns a UDPAddr.
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func (c *UDPConn) ReadFromUDP(b []byte) (int, *UDPAddr, error) {
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if !c.ok() {
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return 0, nil, syscall.EINVAL
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}
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n, addr, err := c.readFrom(b)
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if err != nil {
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err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
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}
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return n, addr, err
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}
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// ReadFrom implements the PacketConn ReadFrom method.
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func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) {
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if !c.ok() {
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return 0, nil, syscall.EINVAL
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}
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n, addr, err := c.readFrom(b)
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if err != nil {
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err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
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}
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if addr == nil {
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return n, nil, err
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}
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return n, addr, err
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}
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// ReadMsgUDP reads a message from c, copying the payload into b and
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// the associated out-of-band data into oob. It returns the number of
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// bytes copied into b, the number of bytes copied into oob, the flags
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// that were set on the message and the source address of the message.
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//
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// The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
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// used to manipulate IP-level socket options in oob.
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func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
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if !c.ok() {
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return 0, 0, 0, nil, syscall.EINVAL
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}
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n, oobn, flags, addr, err = c.readMsg(b, oob)
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if err != nil {
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err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
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}
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return
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}
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// WriteToUDP acts like WriteTo but takes a UDPAddr.
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func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) {
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if !c.ok() {
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return 0, syscall.EINVAL
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}
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n, err := c.writeTo(b, addr)
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if err != nil {
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err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
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}
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return n, err
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}
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// WriteTo implements the PacketConn WriteTo method.
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func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) {
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if !c.ok() {
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return 0, syscall.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{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
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}
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n, err := c.writeTo(b, a)
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if err != nil {
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err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
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}
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return n, err
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}
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// WriteMsgUDP writes a message to addr via c if c isn't connected, or
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// to c's remote address if c is connected (in which case addr must be
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// nil). The payload is copied from b and the associated out-of-band
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// data is copied from oob. It returns the number of payload and
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// out-of-band bytes written.
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//
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// The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
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// used to manipulate IP-level socket options in oob.
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func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
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if !c.ok() {
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return 0, 0, syscall.EINVAL
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}
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n, oobn, err = c.writeMsg(b, oob, addr)
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if err != nil {
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err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
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}
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return
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}
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func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
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// DialUDP acts like Dial for UDP networks.
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//
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// The network must be a UDP network name; see func Dial for details.
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//
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// If laddr is nil, a local address is automatically chosen.
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// If the IP field of raddr is nil or an unspecified IP address, the
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// local system is assumed.
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func DialUDP(network string, laddr, raddr *UDPAddr) (*UDPConn, error) {
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switch network {
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case "udp", "udp4", "udp6":
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default:
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return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
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}
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if raddr == nil {
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return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
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}
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c, err := dialUDP(context.Background(), network, laddr, raddr)
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if err != nil {
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return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
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}
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return c, nil
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}
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// ListenUDP acts like ListenPacket for UDP networks.
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//
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// The network must be a UDP network name; see func Dial for details.
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//
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// If the IP field of laddr is nil or an unspecified IP address,
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// ListenUDP listens on all available IP addresses of the local system
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// except multicast IP addresses.
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// If the Port field of laddr is 0, a port number is automatically
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// chosen.
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func ListenUDP(network string, laddr *UDPAddr) (*UDPConn, error) {
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switch network {
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case "udp", "udp4", "udp6":
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default:
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return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)}
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}
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if laddr == nil {
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laddr = &UDPAddr{}
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}
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c, err := listenUDP(context.Background(), network, laddr)
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if err != nil {
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return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
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}
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return c, nil
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}
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// ListenMulticastUDP acts like ListenPacket for UDP networks but
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// takes a group address on a specific network interface.
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//
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// The network must be a UDP network name; see func Dial for details.
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//
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// ListenMulticastUDP listens on all available IP addresses of the
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// local system including the group, multicast IP address.
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// If ifi is nil, ListenMulticastUDP uses the system-assigned
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// multicast interface, although this is not recommended because the
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// assignment depends on platforms and sometimes it might require
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// routing configuration.
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// If the Port field of gaddr is 0, a port number is automatically
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// chosen.
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//
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// ListenMulticastUDP is just for convenience of simple, small
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// applications. There are golang.org/x/net/ipv4 and
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// golang.org/x/net/ipv6 packages for general purpose uses.
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func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
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switch network {
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case "udp", "udp4", "udp6":
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default:
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return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: UnknownNetworkError(network)}
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}
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if gaddr == nil || gaddr.IP == nil {
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return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: errMissingAddress}
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}
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c, err := listenMulticastUDP(context.Background(), network, ifi, gaddr)
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if err != nil {
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return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: err}
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}
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return c, nil
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}
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