FD.io VPP  v19.01.1-17-ge106252
Vector Packet Processing
How to build a vpp dispatch trace aware Wireshark

We have upstreamed our vpp pcap dispatch trace dissector. After working through a laundry list of issues discovered during the upstreaming process, it appears that the code is close to being merged. See https://code.wireshark.org/review/#/c/31466.

As of this writing, the simplest way to build a vpp dispatch trace aware wireshark is to clone the wireshark repo, and apply the vpp dissector patch.

Download wireshark source code

The wireshark git repo is large, so it takes a while to clone.

1 git clone https://code.wireshark.org/review/wireshark

Download Gerrit 31466 using the URL shown above. If you have "git review" set up, it's as simple as "git review -d 31466" in the wireshark workspace.

Alternatively, download a patch-file from the gerrit server and apply the patch.

Install prerequisite Debian packages

Here is a list of prerequisite packages which must be present in order to compile wireshark, beyond what's typically installed on an Ubuntu 18.04 system:

1 libgcrypt11-dev flex bison qtbase5-dev qttools5-dev-tools qttools5-dev
2 qtmultimedia5-dev libqt5svg5-dev libpcap-dev qt5-default

Compile Wireshark

Wireshark uses cmake, so it's relatively easy to build, at least on Ubuntu 18.04.

1 $ cd wireshark
2 $ mkdir build
3 $ cd build
4 $ cmake -G Ninja ../
5 $ ninja -j 8
6 $ sudo ninja install

Make a pcap dispatch trace

Configure vpp to pass traffic in some fashion or other, and then:

1 vpp# pcap dispatch trace on max 10000 file vppcapture buffer-trace dpdk-input 1000

or similar. Run traffic for long enough to capture some data. Save the dispatch trace capture like so:

1 vpp# pcap dispatch trace off

Display in Wireshark

Display /tmp/vppcapture in the vpp-enabled version of wireshark. Normal version of wireshark will refuse to process vpp dispatch trace pcap files because they won't understand the encap type.

Set wireshark to filter on vpp.bufferindex to watch a single packet traverse the forwarding graph. Otherwise, you'll see a vector of packets in e.g. ip4-lookup, then a vector of packets in ip4-rewrite, etc.