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Source file src/pkg/net/udpsock_posix.go

     1	// Copyright 2009 The Go Authors.  All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// +build darwin dragonfly freebsd linux netbsd openbsd windows
     6	
     7	package net
     8	
     9	import (
    10		"syscall"
    11		"time"
    12	)
    13	
    14	func sockaddrToUDP(sa syscall.Sockaddr) Addr {
    15		switch sa := sa.(type) {
    16		case *syscall.SockaddrInet4:
    17			return &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
    18		case *syscall.SockaddrInet6:
    19			return &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
    20		}
    21		return nil
    22	}
    23	
    24	func (a *UDPAddr) family() int {
    25		if a == nil || len(a.IP) <= IPv4len {
    26			return syscall.AF_INET
    27		}
    28		if a.IP.To4() != nil {
    29			return syscall.AF_INET
    30		}
    31		return syscall.AF_INET6
    32	}
    33	
    34	func (a *UDPAddr) isWildcard() bool {
    35		if a == nil || a.IP == nil {
    36			return true
    37		}
    38		return a.IP.IsUnspecified()
    39	}
    40	
    41	func (a *UDPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
    42		if a == nil {
    43			return nil, nil
    44		}
    45		return ipToSockaddr(family, a.IP, a.Port, a.Zone)
    46	}
    47	
    48	// UDPConn is the implementation of the Conn and PacketConn interfaces
    49	// for UDP network connections.
    50	type UDPConn struct {
    51		conn
    52	}
    53	
    54	func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
    55	
    56	// ReadFromUDP reads a UDP packet from c, copying the payload into b.
    57	// It returns the number of bytes copied into b and the return address
    58	// that was on the packet.
    59	//
    60	// ReadFromUDP can be made to time out and return an error with
    61	// Timeout() == true after a fixed time limit; see SetDeadline and
    62	// SetReadDeadline.
    63	func (c *UDPConn) ReadFromUDP(b []byte) (n int, addr *UDPAddr, err error) {
    64		if !c.ok() {
    65			return 0, nil, syscall.EINVAL
    66		}
    67		n, sa, err := c.fd.ReadFrom(b)
    68		switch sa := sa.(type) {
    69		case *syscall.SockaddrInet4:
    70			addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
    71		case *syscall.SockaddrInet6:
    72			addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
    73		}
    74		return
    75	}
    76	
    77	// ReadFrom implements the PacketConn ReadFrom method.
    78	func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) {
    79		if !c.ok() {
    80			return 0, nil, syscall.EINVAL
    81		}
    82		n, addr, err := c.ReadFromUDP(b)
    83		return n, addr.toAddr(), err
    84	}
    85	
    86	// ReadMsgUDP reads a packet from c, copying the payload into b and
    87	// the associated out-of-band data into oob.  It returns the number
    88	// of bytes copied into b, the number of bytes copied into oob, the
    89	// flags that were set on the packet and the source address of the
    90	// packet.
    91	func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
    92		if !c.ok() {
    93			return 0, 0, 0, nil, syscall.EINVAL
    94		}
    95		var sa syscall.Sockaddr
    96		n, oobn, flags, sa, err = c.fd.ReadMsg(b, oob)
    97		switch sa := sa.(type) {
    98		case *syscall.SockaddrInet4:
    99			addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
   100		case *syscall.SockaddrInet6:
   101			addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
   102		}
   103		return
   104	}
   105	
   106	// WriteToUDP writes a UDP packet to addr via c, copying the payload
   107	// from b.
   108	//
   109	// WriteToUDP can be made to time out and return an error with
   110	// Timeout() == true after a fixed time limit; see SetDeadline and
   111	// SetWriteDeadline.  On packet-oriented connections, write timeouts
   112	// are rare.
   113	func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) {
   114		if !c.ok() {
   115			return 0, syscall.EINVAL
   116		}
   117		if c.fd.isConnected {
   118			return 0, &OpError{"write", c.fd.net, addr, ErrWriteToConnected}
   119		}
   120		if addr == nil {
   121			return 0, &OpError{Op: "write", Net: c.fd.net, Addr: nil, Err: errMissingAddress}
   122		}
   123		sa, err := addr.sockaddr(c.fd.family)
   124		if err != nil {
   125			return 0, &OpError{"write", c.fd.net, addr, err}
   126		}
   127		return c.fd.WriteTo(b, sa)
   128	}
   129	
   130	// WriteTo implements the PacketConn WriteTo method.
   131	func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) {
   132		if !c.ok() {
   133			return 0, syscall.EINVAL
   134		}
   135		a, ok := addr.(*UDPAddr)
   136		if !ok {
   137			return 0, &OpError{"write", c.fd.net, addr, syscall.EINVAL}
   138		}
   139		return c.WriteToUDP(b, a)
   140	}
   141	
   142	// WriteMsgUDP writes a packet to addr via c, copying the payload from
   143	// b and the associated out-of-band data from oob.  It returns the
   144	// number of payload and out-of-band bytes written.
   145	func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
   146		if !c.ok() {
   147			return 0, 0, syscall.EINVAL
   148		}
   149		if c.fd.isConnected {
   150			return 0, 0, &OpError{"write", c.fd.net, addr, ErrWriteToConnected}
   151		}
   152		if addr == nil {
   153			return 0, 0, &OpError{Op: "write", Net: c.fd.net, Addr: nil, Err: errMissingAddress}
   154		}
   155		sa, err := addr.sockaddr(c.fd.family)
   156		if err != nil {
   157			return 0, 0, &OpError{"write", c.fd.net, addr, err}
   158		}
   159		return c.fd.WriteMsg(b, oob, sa)
   160	}
   161	
   162	// DialUDP connects to the remote address raddr on the network net,
   163	// which must be "udp", "udp4", or "udp6".  If laddr is not nil, it is
   164	// used as the local address for the connection.
   165	func DialUDP(net string, laddr, raddr *UDPAddr) (*UDPConn, error) {
   166		switch net {
   167		case "udp", "udp4", "udp6":
   168		default:
   169			return nil, &OpError{Op: "dial", Net: net, Addr: raddr, Err: UnknownNetworkError(net)}
   170		}
   171		if raddr == nil {
   172			return nil, &OpError{Op: "dial", Net: net, Addr: nil, Err: errMissingAddress}
   173		}
   174		return dialUDP(net, laddr, raddr, noDeadline)
   175	}
   176	
   177	func dialUDP(net string, laddr, raddr *UDPAddr, deadline time.Time) (*UDPConn, error) {
   178		fd, err := internetSocket(net, laddr, raddr, deadline, syscall.SOCK_DGRAM, 0, "dial", sockaddrToUDP)
   179		if err != nil {
   180			return nil, &OpError{Op: "dial", Net: net, Addr: raddr, Err: err}
   181		}
   182		return newUDPConn(fd), nil
   183	}
   184	
   185	// ListenUDP listens for incoming UDP packets addressed to the local
   186	// address laddr.  Net must be "udp", "udp4", or "udp6".  If laddr has
   187	// a port of 0, ListenUDP will choose an available port.
   188	// The LocalAddr method of the returned UDPConn can be used to
   189	// discover the port.  The returned connection's ReadFrom and WriteTo
   190	// methods can be used to receive and send UDP packets with per-packet
   191	// addressing.
   192	func ListenUDP(net string, laddr *UDPAddr) (*UDPConn, error) {
   193		switch net {
   194		case "udp", "udp4", "udp6":
   195		default:
   196			return nil, &OpError{Op: "listen", Net: net, Addr: laddr, Err: UnknownNetworkError(net)}
   197		}
   198		if laddr == nil {
   199			laddr = &UDPAddr{}
   200		}
   201		fd, err := internetSocket(net, laddr, nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", sockaddrToUDP)
   202		if err != nil {
   203			return nil, &OpError{Op: "listen", Net: net, Addr: laddr, Err: err}
   204		}
   205		return newUDPConn(fd), nil
   206	}
   207	
   208	// ListenMulticastUDP listens for incoming multicast UDP packets
   209	// addressed to the group address gaddr on ifi, which specifies the
   210	// interface to join.  ListenMulticastUDP uses default multicast
   211	// interface if ifi is nil.
   212	func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
   213		switch net {
   214		case "udp", "udp4", "udp6":
   215		default:
   216			return nil, &OpError{Op: "listen", Net: net, Addr: gaddr, Err: UnknownNetworkError(net)}
   217		}
   218		if gaddr == nil || gaddr.IP == nil {
   219			return nil, &OpError{Op: "listen", Net: net, Addr: nil, Err: errMissingAddress}
   220		}
   221		fd, err := internetSocket(net, gaddr, nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", sockaddrToUDP)
   222		if err != nil {
   223			return nil, &OpError{Op: "listen", Net: net, Addr: gaddr, Err: err}
   224		}
   225		c := newUDPConn(fd)
   226		if ip4 := gaddr.IP.To4(); ip4 != nil {
   227			if err := listenIPv4MulticastUDP(c, ifi, ip4); err != nil {
   228				c.Close()
   229				return nil, &OpError{Op: "listen", Net: net, Addr: &IPAddr{IP: ip4}, Err: err}
   230			}
   231		} else {
   232			if err := listenIPv6MulticastUDP(c, ifi, gaddr.IP); err != nil {
   233				c.Close()
   234				return nil, &OpError{Op: "listen", Net: net, Addr: &IPAddr{IP: gaddr.IP}, Err: err}
   235			}
   236		}
   237		return c, nil
   238	}
   239	
   240	func listenIPv4MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
   241		if ifi != nil {
   242			if err := setIPv4MulticastInterface(c.fd, ifi); err != nil {
   243				return err
   244			}
   245		}
   246		if err := setIPv4MulticastLoopback(c.fd, false); err != nil {
   247			return err
   248		}
   249		if err := joinIPv4Group(c.fd, ifi, ip); err != nil {
   250			return err
   251		}
   252		return nil
   253	}
   254	
   255	func listenIPv6MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
   256		if ifi != nil {
   257			if err := setIPv6MulticastInterface(c.fd, ifi); err != nil {
   258				return err
   259			}
   260		}
   261		if err := setIPv6MulticastLoopback(c.fd, false); err != nil {
   262			return err
   263		}
   264		if err := joinIPv6Group(c.fd, ifi, ip); err != nil {
   265			return err
   266		}
   267		return nil
   268	}

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