xdpcap

Overview ¶

Program xdpcap produces tcpdump compatible PCAPs from a BPF map.

You can use it to introspect traffic dropped or redirected by XDP. It is also useful to examine any transformations done to a packet.

xdpcap requires you to instrument your XDP code in a specific way, check the documentation at https://github.com/cloudflare/xdpcap for details.

Once you have done so, you can capture into a file, or pipe straight into tcpdump:

xdpcap /path/to/pinned/map file.pcap
xdpcap /path/to/pinned/map - | tcpdump -r -

xdpcap supports tcpdump / libpcap-style filter expressions.