github.com/hxx258456/ccgo@v0.0.5-0.20230213014102-48b35f46f66f/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  //go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris && !zos
     6  // +build !aix,!darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris,!zos
     7  
     8  package ipv4
     9  
    10  import "net"
    11  
    12  // ReadFrom reads a payload of the received IPv4 datagram, from the
    13  // endpoint c, copying the payload into b. It returns the number of
    14  // bytes copied into b, the control message cm and the source address
    15  // src of the received datagram.
    16  func (c *payloadHandler) ReadFrom(b []byte) (n int, cm *ControlMessage, src net.Addr, err error) {
    17  	if !c.ok() {
    18  		return 0, nil, nil, errInvalidConn
    19  	}
    20  	if n, src, err = c.PacketConn.ReadFrom(b); err != nil {
    21  		return 0, nil, nil, err
    22  	}
    23  	return
    24  }
    25  
    26  // WriteTo writes a payload of the IPv4 datagram, to the destination
    27  // address dst through the endpoint c, copying the payload from b. It
    28  // returns the number of bytes written. The control message cm allows
    29  // the datagram path and the outgoing interface to be specified.
    30  // Currently only Darwin and Linux support this. The cm may be nil if
    31  // control of the outgoing datagram is not required.
    32  func (c *payloadHandler) WriteTo(b []byte, cm *ControlMessage, dst net.Addr) (n int, err error) {
    33  	if !c.ok() {
    34  		return 0, errInvalidConn
    35  	}
    36  	if dst == nil {
    37  		return 0, errMissingAddress
    38  	}
    39  	return c.PacketConn.WriteTo(b, dst)
    40  }