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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !go1.9
package ipv4
import "net"
func (c *packetHandler) readFrom(b []byte) (h *Header, p []byte, cm *ControlMessage, err error) {
c.rawOpt.RLock()
oob := NewControlMessage(c.rawOpt.cflags)
c.rawOpt.RUnlock()
n, nn, _, src, err := c.ReadMsgIP(b, oob)
if err != nil {
return nil, nil, nil, err
}
var hs []byte
if hs, p, err = slicePacket(b[:n]); err != nil {
return nil, nil, nil, err
}
if h, err = ParseHeader(hs); err != nil {
return nil, nil, nil, err
}
if nn > 0 {
cm = new(ControlMessage)
if err := cm.Parse(oob[:nn]); err != nil {
return nil, nil, nil, err
}
}
if src != nil && cm != nil {
cm.Src = src.IP
}
return
}
func (c *packetHandler) writeTo(h *Header, p []byte, cm *ControlMessage) error {
oob := cm.Marshal()
wh, err := h.Marshal()
if err != nil {
return err
}
dst := new(net.IPAddr)
if cm != nil {
if ip := cm.Dst.To4(); ip != nil {
dst.IP = ip
}
}
if dst.IP == nil {
dst.IP = h.Dst
}
wh = append(wh, p...)
_, _, err = c.WriteMsgIP(wh, oob, dst)
return err
}
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