github.com/Andyfoo/golang/x/net@v0.0.0-20190901054642-57c1bf301704/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 !aix,!darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris
     6  
     7  package ipv4
     8  
     9  import "net"
    10  
    11  // ReadFrom reads a payload of the received IPv4 datagram, from the
    12  // endpoint c, copying the payload into b. It returns the number of
    13  // bytes copied into b, the control message cm and the source address
    14  // src of the received datagram.
    15  func (c *payloadHandler) ReadFrom(b []byte) (n int, cm *ControlMessage, src net.Addr, err error) {
    16  	if !c.ok() {
    17  		return 0, nil, nil, errInvalidConn
    18  	}
    19  	if n, src, err = c.PacketConn.ReadFrom(b); err != nil {
    20  		return 0, nil, nil, err
    21  	}
    22  	return
    23  }
    24  
    25  // WriteTo writes a payload of the IPv4 datagram, to the destination
    26  // address dst through the endpoint c, copying the payload from b. It
    27  // returns the number of bytes written. The control message cm allows
    28  // the datagram path and the outgoing interface to be specified.
    29  // Currently only Darwin and Linux support this. The cm may be nil if
    30  // control of the outgoing datagram is not required.
    31  func (c *payloadHandler) WriteTo(b []byte, cm *ControlMessage, dst net.Addr) (n int, err error) {
    32  	if !c.ok() {
    33  		return 0, errInvalidConn
    34  	}
    35  	if dst == nil {
    36  		return 0, errMissingAddress
    37  	}
    38  	return c.PacketConn.WriteTo(b, dst)
    39  }