// Copyright 2017 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" "golang.org/x/net/internal/socket" ) func (c *packetHandler) readFrom(b []byte) (h *Header, p []byte, cm *ControlMessage, err error) { c.rawOpt.RLock() m := socket.Message{ Buffers: [][]byte{b}, OOB: NewControlMessage(c.rawOpt.cflags), } c.rawOpt.RUnlock() if err := c.RecvMsg(&m, 0); err != nil { return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} } var hs []byte if hs, p, err = slicePacket(b[:m.N]); err != nil { return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} } if h, err = ParseHeader(hs); err != nil { return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} } if m.NN > 0 { cm = new(ControlMessage) if err := cm.Parse(m.OOB[:m.NN]); err != nil { return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err} } } if src, ok := m.Addr.(*net.IPAddr); ok && cm != nil { cm.Src = src.IP } return } func (c *packetHandler) writeTo(h *Header, p []byte, cm *ControlMessage) error { m := socket.Message{ OOB: cm.Marshal(), } wh, err := h.Marshal() if err != nil { return err } m.Buffers = [][]byte{wh, p} 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 } m.Addr = dst if err := c.SendMsg(&m, 0); err != nil { return &net.OpError{Op: "write", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Addr: opAddr(dst), Err: err} } return nil }