github.com/graybobo/golang.org-package-offline-cache@v0.0.0-20200626051047-6608995c132f/x/net/ipv4/payload_nocmsg.go (about)

     1  // Copyright 2012 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 plan9 solaris windows
     6  
     7  package ipv4
     8  
     9  import (
    10  	"net"
    11  	"syscall"
    12  )
    13  
    14  // ReadFrom reads a payload of the received IPv4 datagram, from the
    15  // endpoint c, copying the payload into b.  It returns the number of
    16  // bytes copied into b, the control message cm and the source address
    17  // src of the received datagram.
    18  func (c *payloadHandler) ReadFrom(b []byte) (n int, cm *ControlMessage, src net.Addr, err error) {
    19  	if !c.ok() {
    20  		return 0, nil, nil, syscall.EINVAL
    21  	}
    22  	if n, src, err = c.PacketConn.ReadFrom(b); err != nil {
    23  		return 0, nil, nil, err
    24  	}
    25  	return
    26  }
    27  
    28  // WriteTo writes a payload of the IPv4 datagram, to the destination
    29  // address dst through the endpoint c, copying the payload from b.  It
    30  // returns the number of bytes written.  The control message cm allows
    31  // the datagram path and the outgoing interface to be specified.
    32  // Currently only Darwin and Linux support this.  The cm may be nil if
    33  // control of the outgoing datagram is not required.
    34  func (c *payloadHandler) WriteTo(b []byte, cm *ControlMessage, dst net.Addr) (n int, err error) {
    35  	if !c.ok() {
    36  		return 0, syscall.EINVAL
    37  	}
    38  	if dst == nil {
    39  		return 0, errMissingAddress
    40  	}
    41  	return c.PacketConn.WriteTo(b, dst)
    42  }