examples/testdata

The L2 program and its P4Info for the examples and integration tests.

File	Purpose
l2.p4	Source for the minimal L2 switch program.
l2.p4info.txt	Generated P4Info in text format, checked in for metadata lookups.
l2.bmv2.json	Generated BMv2 device config, kept out of Git.

Regenerate

./scripts/compile-l2.sh

The script requires p4c-bm2-ss, included with p4c. It generates both files from the same source in one compilation. Pass an output directory to keep a separate pair, for example ./scripts/compile-l2.sh /tmp/l2. Use both files from that directory when installing the pipeline. Do not combine a new JSON with an older P4Info.

Resources and packet flow

MyIngress.t_l2 matches hdr.eth.dst. Its MyIngress.forward(port) action sends a matching Ethernet frame to the specified 9-bit port. An unmatched frame goes to CPU port 255 as a PacketIn.

MyIngress.pkt_counter has 512 entries. The forward action counts packets and bytes at the egress port's index. MyIngress.pkt_counter_direct counts the same traffic for each L2 table entry. PacketOut bypasses the L2 table.

PacketIn metadata contains ingress_port and _pad. PacketOut metadata contains egress_port and _pad. Both port fields are 9 bits, and _pad is 7 bits with value zero. The payload is a complete Ethernet frame. The P4 parser removes the PacketOut control header, and the deparser prepends a PacketIn control header only for frames sent to port 255.

Native BMv2

Start a local target with device ID 1 and CPU port 255. The launcher compiles both artifacts first:

./scripts/run-bmv2.sh

For traffic, bind existing host-facing interfaces with --interface 1@veth1 --interface 2@veth2. BMv2 needs permission to open raw sockets on them. Examples 02 and 03 use port 1 by default in their documented commands. Docker mode provides a control plane target through --docker; host interface bindings use native mode. See the script guide.