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Source file src/net/udpsock_posix.go

Documentation: net

     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 js,wasm 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: zoneCache.name(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 (a *UDPAddr) toLocal(net string) sockaddr {
    42  	return &UDPAddr{loopbackIP(net), a.Port, a.Zone}
    43  }
    44  
    45  func (c *UDPConn) readFrom(b []byte) (int, *UDPAddr, error) {
    46  	var addr *UDPAddr
    47  	n, sa, err := c.fd.readFrom(b)
    48  	switch sa := sa.(type) {
    49  	case *syscall.SockaddrInet4:
    50  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
    51  	case *syscall.SockaddrInet6:
    52  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneCache.name(int(sa.ZoneId))}
    53  	}
    54  	return n, addr, err
    55  }
    56  
    57  func (c *UDPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
    58  	var sa syscall.Sockaddr
    59  	n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
    60  	switch sa := sa.(type) {
    61  	case *syscall.SockaddrInet4:
    62  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}
    63  	case *syscall.SockaddrInet6:
    64  		addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneCache.name(int(sa.ZoneId))}
    65  	}
    66  	return
    67  }
    68  
    69  func (c *UDPConn) writeTo(b []byte, addr *UDPAddr) (int, error) {
    70  	if c.fd.isConnected {
    71  		return 0, ErrWriteToConnected
    72  	}
    73  	if addr == nil {
    74  		return 0, errMissingAddress
    75  	}
    76  	sa, err := addr.sockaddr(c.fd.family)
    77  	if err != nil {
    78  		return 0, err
    79  	}
    80  	return c.fd.writeTo(b, sa)
    81  }
    82  
    83  func (c *UDPConn) writeMsg(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
    84  	if c.fd.isConnected && addr != nil {
    85  		return 0, 0, ErrWriteToConnected
    86  	}
    87  	if !c.fd.isConnected && addr == nil {
    88  		return 0, 0, errMissingAddress
    89  	}
    90  	sa, err := addr.sockaddr(c.fd.family)
    91  	if err != nil {
    92  		return 0, 0, err
    93  	}
    94  	return c.fd.writeMsg(b, oob, sa)
    95  }
    96  
    97  func (sd *sysDialer) dialUDP(ctx context.Context, laddr, raddr *UDPAddr) (*UDPConn, error) {
    98  	fd, err := internetSocket(ctx, sd.network, laddr, raddr, syscall.SOCK_DGRAM, 0, "dial", sd.Dialer.Control)
    99  	if err != nil {
   100  		return nil, err
   101  	}
   102  	return newUDPConn(fd), nil
   103  }
   104  
   105  func (sl *sysListener) listenUDP(ctx context.Context, laddr *UDPAddr) (*UDPConn, error) {
   106  	fd, err := internetSocket(ctx, sl.network, laddr, nil, syscall.SOCK_DGRAM, 0, "listen", sl.ListenConfig.Control)
   107  	if err != nil {
   108  		return nil, err
   109  	}
   110  	return newUDPConn(fd), nil
   111  }
   112  
   113  func (sl *sysListener) listenMulticastUDP(ctx context.Context, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
   114  	fd, err := internetSocket(ctx, sl.network, gaddr, nil, syscall.SOCK_DGRAM, 0, "listen", sl.ListenConfig.Control)
   115  	if err != nil {
   116  		return nil, err
   117  	}
   118  	c := newUDPConn(fd)
   119  	if ip4 := gaddr.IP.To4(); ip4 != nil {
   120  		if err := listenIPv4MulticastUDP(c, ifi, ip4); err != nil {
   121  			c.Close()
   122  			return nil, err
   123  		}
   124  	} else {
   125  		if err := listenIPv6MulticastUDP(c, ifi, gaddr.IP); err != nil {
   126  			c.Close()
   127  			return nil, err
   128  		}
   129  	}
   130  	return c, nil
   131  }
   132  
   133  func listenIPv4MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
   134  	if ifi != nil {
   135  		if err := setIPv4MulticastInterface(c.fd, ifi); err != nil {
   136  			return err
   137  		}
   138  	}
   139  	if err := setIPv4MulticastLoopback(c.fd, false); err != nil {
   140  		return err
   141  	}
   142  	if err := joinIPv4Group(c.fd, ifi, ip); err != nil {
   143  		return err
   144  	}
   145  	return nil
   146  }
   147  
   148  func listenIPv6MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
   149  	if ifi != nil {
   150  		if err := setIPv6MulticastInterface(c.fd, ifi); err != nil {
   151  			return err
   152  		}
   153  	}
   154  	if err := setIPv6MulticastLoopback(c.fd, false); err != nil {
   155  		return err
   156  	}
   157  	if err := joinIPv6Group(c.fd, ifi, ip); err != nil {
   158  		return err
   159  	}
   160  	return nil
   161  }
   162  

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