42 lines
980 B
Go
42 lines
980 B
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build darwin || linux || solaris
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package ipv4
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import (
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"net"
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"unsafe"
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"golang.org/x/net/internal/iana"
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"golang.org/x/net/internal/socket"
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"golang.org/x/sys/unix"
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)
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func marshalPacketInfo(b []byte, cm *ControlMessage) []byte {
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m := socket.ControlMessage(b)
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m.MarshalHeader(iana.ProtocolIP, unix.IP_PKTINFO, sizeofInetPktinfo)
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if cm != nil {
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pi := (*inetPktinfo)(unsafe.Pointer(&m.Data(sizeofInetPktinfo)[0]))
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if ip := cm.Src.To4(); ip != nil {
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copy(pi.Spec_dst[:], ip)
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}
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if cm.IfIndex > 0 {
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pi.setIfindex(cm.IfIndex)
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}
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}
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return m.Next(sizeofInetPktinfo)
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}
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func parsePacketInfo(cm *ControlMessage, b []byte) {
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pi := (*inetPktinfo)(unsafe.Pointer(&b[0]))
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cm.IfIndex = int(pi.Ifindex)
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if len(cm.Dst) < net.IPv4len {
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cm.Dst = make(net.IP, net.IPv4len)
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}
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copy(cm.Dst, pi.Addr[:])
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}
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