Unfortunately, as things stand, the tunnel should compute the checksum before encapsulating the traffic. Otherwise the output node won’t be able to find the right headers.
Will look into simplifying this. Florin > On Apr 29, 2019, at 8:18 AM, Andreas Schultz <andreas.schu...@travelping.com> > wrote: > > Thanks, that helped a lot. I found that traffic is not passing through the > node as I expected it. > > The actual graph is > > tcp4-output -> ip4-lookup -> ip4-rewrite -> upf-if-input > > Note: upf-if-input is the node function of an interface. It is found through > a fib entry that look like this: > > 10.106.14.227/32 <http://10.106.14.227/32> > unicast-ip4-chain > [@0]: dpo-load-balance: [proto:ip4 index:38 buckets:1 uRPF:43 to:[0:0]] > [0] [@5]: ipv4 via 0.0.0.0 upf_session1: mtu:9000 > > What I was expecting that between ip4-rewrite and upf-if-input the > vnet_interface_output_node function of the software interface would be > invoked. > > As far as I can see that is the only logical place that would calculate check > sums and do segmentation on for software interfaces. > For routed traffic that is normally not needed, but locally generated traffic > (like a local TCP endpoint) needs it. > > It feels like I'm missing a important piece of the picture here. > What function or node should fill in the checksum for locally generate > traffic before it is encapsulated into a tunnel and what might be wrong that > it does not work in my setup? > > Many Thanks, > Andreas > > Am Mo., 29. Apr. 2019 um 16:59 Uhr schrieb Dave Barach (dbarach) > <dbar...@cisco.com <mailto:dbar...@cisco.com>>: > Try “pcap dispatch trace on max 10000 buffer-trace <rx-interface-input-node> > 1000”, cause a transaction, “pcap dispatch trace off”; then look at the > resulting trace w/ a vpp-dispatch-trace enabled wireshark. See > https://fdio-vpp.readthedocs.io/en/latest/gettingstarted/developers/buildwireshark.html > > <https://fdio-vpp.readthedocs.io/en/latest/gettingstarted/developers/buildwireshark.html> > > > HTH... Dave > > > > > > From: <vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io>> on behalf of Andreas > Schultz <andreas.schu...@travelping.com > <mailto:andreas.schu...@travelping.com>> > Date: Monday, April 29, 2019 at 9:31 AM > To: "vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io>" <vpp-dev@lists.fd.io > <mailto:vpp-dev@lists.fd.io>> > Subject: [vpp-dev] how to trace tcp4-output? > > > > Hi, > > > > I'm trying to debug a problem and need to trace tcp4-output with vpp 19.04. > > > > So far I have tried it with "trace add tcp4-output 100 verbose", but that is > not producing the expected result. The trace buffer is always empty. > > > > I was expecting that "trace add af-packet-input 100" would also trace the > replies. But I can only see the incoming TCP-SYN, the generated SYN+ACK and > the tcp4-output nodes are not showing up in the trace. > > I do know that the SYN+ACK gets generate, because I can see it in tcpdump > after it has gone through an encapsulation. > > > > The problem I'm trying to figure out is why the TCP SYN+ACK packet when it > hits a tunnel encapsulation node has invalid (or even no) check sums. I > suspect there is something going on with the csum offload. But without the > trace, finding that problem is a nightmare. > > > > Many thanks, > > Andreas > > > > > > -- > > -- > Dipl.-Inform. Andreas Schultz > > ----------------------- enabling your networks ---------------------- > Travelping GmbH Phone: +49-391-81 90 99 0 > Roentgenstr. 13 Fax: +49-391-81 90 99 299 > 39108 Magdeburg Email: i...@travelping.com > <mailto:i...@travelping.com> > GERMANY Web: http://www.travelping.com > <http://www.travelping.com/> > Company Registration: Amtsgericht Stendal Reg No.: HRB 10578 > > Geschaeftsfuehrer: Holger Winkelmann VAT ID No.: DE236673780 > --------------------------------------------------------------------- > > > > -- > -- > Dipl.-Inform. Andreas Schultz > > ----------------------- enabling your networks ---------------------- > Travelping GmbH Phone: +49-391-81 90 99 0 > Roentgenstr. 13 Fax: +49-391-81 90 99 299 > 39108 Magdeburg Email: i...@travelping.com > <mailto:i...@travelping.com> > GERMANY Web: http://www.travelping.com > <http://www.travelping.com/> > > Company Registration: Amtsgericht Stendal Reg No.: HRB 10578 > Geschaeftsfuehrer: Holger Winkelmann VAT ID No.: DE236673780 > --------------------------------------------------------------------- > -=-=-=-=-=-=-=-=-=-=-=- > Links: You receive all messages sent to this group. > > View/Reply Online (#12873): https://lists.fd.io/g/vpp-dev/message/12873 > <https://lists.fd.io/g/vpp-dev/message/12873> > Mute This Topic: https://lists.fd.io/mt/31383412/675152 > <https://lists.fd.io/mt/31383412/675152> > Group Owner: vpp-dev+ow...@lists.fd.io <mailto:vpp-dev+ow...@lists.fd.io> > Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub > <https://lists.fd.io/g/vpp-dev/unsub> [fcoras.li...@gmail.com > <mailto:fcoras.li...@gmail.com>] > -=-=-=-=-=-=-=-=-=-=-=-
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