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
HTH... Dave From: <vpp-dev@lists.fd.io> on behalf of Andreas Schultz <andreas.schu...@travelping.com> Date: Monday, April 29, 2019 at 9:31 AM To: "vpp-dev@lists.fd.io" <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 Company Registration: Amtsgericht Stendal Reg No.: HRB 10578 Geschaeftsfuehrer: Holger Winkelmann VAT ID No.: DE236673780 ---------------------------------------------------------------------
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