github.com/mh-cbon/go@v0.0.0-20160603070303-9e112a3fe4c0/src/net/udpsock_posix.go (about)

     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 nacl netbsd openbsd solaris windows
     6  
     7  package net
     8  
     9  import (
    10  	"context"
    11  	"syscall"
    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) sockaddr(family int) (syscall.Sockaddr, error) {
    35  	if a == nil {
    36  		return nil, nil
    37  	}
    38  	return ipToSockaddr(family, a.IP, a.Port, a.Zone)
    39  }
    40  
    41  func (c *UDPConn) readFrom(b []byte) (int, *UDPAddr, error) {
    42  	var addr *UDPAddr
    43  	n, sa, err := c.fd.readFrom(b)
    44  	switch sa := sa.(type) {
    45  	case *syscall.SockaddrInet4:
    46  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
    47  	case *syscall.SockaddrInet6:
    48  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
    49  	}
    50  	return n, addr, err
    51  }
    52  
    53  func (c *UDPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
    54  	var sa syscall.Sockaddr
    55  	n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
    56  	switch sa := sa.(type) {
    57  	case *syscall.SockaddrInet4:
    58  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
    59  	case *syscall.SockaddrInet6:
    60  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
    61  	}
    62  	return
    63  }
    64  
    65  func (c *UDPConn) writeTo(b []byte, addr *UDPAddr) (int, error) {
    66  	if c.fd.isConnected {
    67  		return 0, ErrWriteToConnected
    68  	}
    69  	if addr == nil {
    70  		return 0, errMissingAddress
    71  	}
    72  	sa, err := addr.sockaddr(c.fd.family)
    73  	if err != nil {
    74  		return 0, err
    75  	}
    76  	return c.fd.writeTo(b, sa)
    77  }
    78  
    79  func (c *UDPConn) writeMsg(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
    80  	if c.fd.isConnected && addr != nil {
    81  		return 0, 0, ErrWriteToConnected
    82  	}
    83  	if !c.fd.isConnected && addr == nil {
    84  		return 0, 0, errMissingAddress
    85  	}
    86  	sa, err := addr.sockaddr(c.fd.family)
    87  	if err != nil {
    88  		return 0, 0, err
    89  	}
    90  	return c.fd.writeMsg(b, oob, sa)
    91  }
    92  
    93  func dialUDP(ctx context.Context, net string, laddr, raddr *UDPAddr) (*UDPConn, error) {
    94  	fd, err := internetSocket(ctx, net, laddr, raddr, syscall.SOCK_DGRAM, 0, "dial")
    95  	if err != nil {
    96  		return nil, err
    97  	}
    98  	return newUDPConn(fd), nil
    99  }
   100  
   101  func listenUDP(ctx context.Context, network string, laddr *UDPAddr) (*UDPConn, error) {
   102  	fd, err := internetSocket(ctx, network, laddr, nil, syscall.SOCK_DGRAM, 0, "listen")
   103  	if err != nil {
   104  		return nil, err
   105  	}
   106  	return newUDPConn(fd), nil
   107  }
   108  
   109  func listenMulticastUDP(ctx context.Context, network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
   110  	fd, err := internetSocket(ctx, network, gaddr, nil, syscall.SOCK_DGRAM, 0, "listen")
   111  	if err != nil {
   112  		return nil, err
   113  	}
   114  	c := newUDPConn(fd)
   115  	if ip4 := gaddr.IP.To4(); ip4 != nil {
   116  		if err := listenIPv4MulticastUDP(c, ifi, ip4); err != nil {
   117  			c.Close()
   118  			return nil, err
   119  		}
   120  	} else {
   121  		if err := listenIPv6MulticastUDP(c, ifi, gaddr.IP); err != nil {
   122  			c.Close()
   123  			return nil, err
   124  		}
   125  	}
   126  	return c, nil
   127  }
   128  
   129  func listenIPv4MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
   130  	if ifi != nil {
   131  		if err := setIPv4MulticastInterface(c.fd, ifi); err != nil {
   132  			return err
   133  		}
   134  	}
   135  	if err := setIPv4MulticastLoopback(c.fd, false); err != nil {
   136  		return err
   137  	}
   138  	if err := joinIPv4Group(c.fd, ifi, ip); err != nil {
   139  		return err
   140  	}
   141  	return nil
   142  }
   143  
   144  func listenIPv6MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
   145  	if ifi != nil {
   146  		if err := setIPv6MulticastInterface(c.fd, ifi); err != nil {
   147  			return err
   148  		}
   149  	}
   150  	if err := setIPv6MulticastLoopback(c.fd, false); err != nil {
   151  		return err
   152  	}
   153  	if err := joinIPv6Group(c.fd, ifi, ip); err != nil {
   154  		return err
   155  	}
   156  	return nil
   157  }