payload_cmsg.go raw

   1  // Copyright 2013 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  //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
   6  
   7  package ipv6
   8  
   9  import (
  10  	"net"
  11  
  12  	"golang.org/x/net/internal/socket"
  13  )
  14  
  15  // ReadFrom reads a payload of the received IPv6 datagram, from the
  16  // endpoint c, copying the payload into b. It returns the number of
  17  // bytes copied into b, the control message cm and the source address
  18  // src of the received datagram.
  19  func (c *payloadHandler) ReadFrom(b []byte) (n int, cm *ControlMessage, src net.Addr, err error) {
  20  	if !c.ok() {
  21  		return 0, nil, nil, errInvalidConn
  22  	}
  23  	c.rawOpt.RLock()
  24  	m := socket.Message{
  25  		Buffers: [][]byte{b},
  26  		OOB:     NewControlMessage(c.rawOpt.cflags),
  27  	}
  28  	c.rawOpt.RUnlock()
  29  	switch c.PacketConn.(type) {
  30  	case *net.UDPConn:
  31  		if err := c.RecvMsg(&m, 0); err != nil {
  32  			return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
  33  		}
  34  	case *net.IPConn:
  35  		if err := c.RecvMsg(&m, 0); err != nil {
  36  			return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
  37  		}
  38  	default:
  39  		return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: errInvalidConnType}
  40  	}
  41  	if m.NN > 0 {
  42  		cm = new(ControlMessage)
  43  		if err := cm.Parse(m.OOB[:m.NN]); err != nil {
  44  			return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
  45  		}
  46  		cm.Src = netAddrToIP16(m.Addr)
  47  	}
  48  	return m.N, cm, m.Addr, nil
  49  }
  50  
  51  // WriteTo writes a payload of the IPv6 datagram, to the destination
  52  // address dst through the endpoint c, copying the payload from b. It
  53  // returns the number of bytes written. The control message cm allows
  54  // the IPv6 header fields and the datagram path to be specified. The
  55  // cm may be nil if control of the outgoing datagram is not required.
  56  func (c *payloadHandler) WriteTo(b []byte, cm *ControlMessage, dst net.Addr) (n int, err error) {
  57  	if !c.ok() {
  58  		return 0, errInvalidConn
  59  	}
  60  	m := socket.Message{
  61  		Buffers: [][]byte{b},
  62  		OOB:     cm.Marshal(),
  63  		Addr:    dst,
  64  	}
  65  	err = c.SendMsg(&m, 0)
  66  	if err != nil {
  67  		err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Addr: opAddr(dst), Err: err}
  68  	}
  69  	return m.N, err
  70  }
  71