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TUN-6744: On posix platforms, assign unique echo ID per (src, dst, echo ID)

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This also refactor FunnelTracker to provide a GetOrRegister method to prevent race condition
This commit is contained in:
cthuang
2022-09-09 16:48:42 +01:00
parent e454994e3e
commit b639b6627a
7 changed files with 268 additions and 138 deletions
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73
ingress/icmp_linux.go
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@@ -57,45 +57,57 @@ func (ip *icmpProxy) Request(pk *packet.ICMP, responder packet.FunnelUniPipe) er
if pk == nil {
return errPacketNil
}
funnelID := srcIPFunnelID(pk.Src)
funnel, exists := ip.srcFunnelTracker.Get(funnelID)
if !exists {
originalEcho, err := getICMPEcho(pk.Message)
if err != nil {
return err
}
originalEcho, err := getICMPEcho(pk.Message)
if err != nil {
return err
}
newConnChan := make(chan *icmp.PacketConn, 1)
newFunnelFunc := func() (packet.Funnel, error) {
conn, err := newICMPConn(ip.listenIP)
if err != nil {
return errors.Wrap(err, "failed to open ICMP socket")
return nil, errors.Wrap(err, "failed to open ICMP socket")
}
newConnChan <- conn
localUDPAddr, ok := conn.LocalAddr().(*net.UDPAddr)
if !ok {
return fmt.Errorf("ICMP listener address %s is not net.UDPAddr", conn.LocalAddr())
return nil, fmt.Errorf("ICMP listener address %s is not net.UDPAddr", conn.LocalAddr())
}
originSender := originSender{conn: conn}
echoID := localUDPAddr.Port
icmpFlow := newICMPEchoFlow(pk.Src, &originSender, responder, echoID, originalEcho.ID, packet.NewEncoder())
if replaced := ip.srcFunnelTracker.Register(funnelID, icmpFlow); replaced {
ip.logger.Info().Str("src", pk.Src.String()).Msg("Replaced funnel")
}
if err := icmpFlow.sendToDst(pk.Dst, pk.Message); err != nil {
return errors.Wrap(err, "failed to send ICMP echo request")
}
go func() {
defer ip.srcFunnelTracker.Unregister(funnelID, icmpFlow)
if err := ip.listenResponse(icmpFlow, conn); err != nil {
ip.logger.Err(err).
Str("funnelID", funnelID.String()).
Int("echoID", echoID).
Msg("Failed to listen for ICMP echo response")
}
}()
return nil
return icmpFlow, nil
}
funnelID := flow3Tuple{
srcIP: pk.Src,
dstIP: pk.Dst,
originalEchoID: originalEcho.ID,
}
funnel, isNew, err := ip.srcFunnelTracker.GetOrRegister(funnelID, newFunnelFunc)
if err != nil {
return err
}
icmpFlow, err := toICMPEchoFlow(funnel)
if err != nil {
return err
}
if isNew {
ip.logger.Debug().
Str("src", pk.Src.String()).
Str("dst", pk.Dst.String()).
Int("originalEchoID", originalEcho.ID).
Msg("New flow")
conn := <-newConnChan
go func() {
defer ip.srcFunnelTracker.Unregister(funnelID, icmpFlow)
if err := ip.listenResponse(icmpFlow, conn); err != nil {
ip.logger.Debug().Err(err).
Str("src", pk.Src.String()).
Str("dst", pk.Dst.String()).
Int("originalEchoID", originalEcho.ID).
Msg("Failed to listen for ICMP echo response")
}
}()
}
if err := icmpFlow.sendToDst(pk.Dst, pk.Message); err != nil {
return errors.Wrap(err, "failed to send ICMP echo request")
}
@@ -146,12 +158,11 @@ func (os *originSender) Close() error {
return os.conn.Close()
}
type srcIPFunnelID netip.Addr
func (sifd srcIPFunnelID) Type() string {
return "srcIP"
// Only linux uses flow3Tuple as FunnelID
func (ft flow3Tuple) Type() string {
return "srcIP_dstIP_echoID"
}
func (sifd srcIPFunnelID) String() string {
return netip.Addr(sifd).String()
func (ft flow3Tuple) String() string {
return fmt.Sprintf("%s:%s:%d", ft.srcIP, ft.dstIP, ft.originalEchoID)
}