38 lines
894 B
Go
38 lines
894 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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// +build darwin linux
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package ipv4
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import (
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"syscall"
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"unsafe"
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"golang.org/x/net/internal/iana"
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)
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func marshalPacketInfo(b []byte, cm *ControlMessage) []byte {
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m := (*syscall.Cmsghdr)(unsafe.Pointer(&b[0]))
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m.Level = iana.ProtocolIP
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m.Type = sysIP_PKTINFO
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m.SetLen(syscall.CmsgLen(sysSizeofInetPktinfo))
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if cm != nil {
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pi := (*sysInetPktinfo)(unsafe.Pointer(&b[syscall.CmsgLen(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 b[syscall.CmsgSpace(sysSizeofInetPktinfo):]
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}
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func parsePacketInfo(cm *ControlMessage, b []byte) {
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pi := (*sysInetPktinfo)(unsafe.Pointer(&b[0]))
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cm.IfIndex = int(pi.Ifindex)
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cm.Dst = pi.Addr[:]
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}
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