87 lines
2 KiB
Go
87 lines
2 KiB
Go
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// Copyright 2020 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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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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)
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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, sysIP_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.Addr[:], 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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func setControlMessage(c *socket.Conn, opt *rawOpt, cf ControlFlags, on bool) error {
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opt.Lock()
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defer opt.Unlock()
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if so, ok := sockOpts[ssoReceiveTTL]; ok && cf&FlagTTL != 0 {
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if err := so.SetInt(c, boolint(on)); err != nil {
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return err
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}
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if on {
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opt.set(FlagTTL)
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} else {
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opt.clear(FlagTTL)
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}
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}
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if so, ok := sockOpts[ssoPacketInfo]; ok {
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if cf&(FlagSrc|FlagDst|FlagInterface) != 0 {
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if err := so.SetInt(c, boolint(on)); err != nil {
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return err
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}
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if on {
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opt.set(cf & (FlagSrc | FlagDst | FlagInterface))
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} else {
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opt.clear(cf & (FlagSrc | FlagDst | FlagInterface))
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}
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}
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} else {
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if so, ok := sockOpts[ssoReceiveDst]; ok && cf&FlagDst != 0 {
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if err := so.SetInt(c, boolint(on)); err != nil {
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return err
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}
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if on {
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opt.set(FlagDst)
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} else {
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opt.clear(FlagDst)
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}
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}
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if so, ok := sockOpts[ssoReceiveInterface]; ok && cf&FlagInterface != 0 {
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if err := so.SetInt(c, boolint(on)); err != nil {
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return err
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}
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if on {
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opt.set(FlagInterface)
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} else {
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opt.clear(FlagInterface)
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}
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}
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}
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return nil
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}
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