Add local vhost loopback example for single-machine development - #57
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sarsanaee wants to merge 1 commit into
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Add local vhost loopback example for single-machine development#57sarsanaee wants to merge 1 commit into
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Machnet previously required a physical DPDK NIC (and typically a pair of cloud VMs) to try anything end-to-end. This adds a self-contained local test that runs the full datapath on one Linux machine using DPDK virtual devices: a net_vhost port and a virtio_user port wired back-to-back over a unix socket, driven by the existing hello_world app. - examples/local_vhost_test.sh: starts the daemon on the vhost pair and verifies a hello_world message crosses the loop; heavily commented so it doubles as local-development documentation. - examples/local_vhost_config.json: two-interface config for the loop. - machnet_config: new optional per-interface "vdev" key, passed to DPDK as --vdev (plus --no-pci when no physical ports are configured). vdev arguments are sorted so DPDK port ids -- and thus the net_vhost MAC, which is derived from the port id -- are deterministic. - pmd.cc: fall back to a basic ethernet configuration with a warning, instead of LOG(FATAL), when a port lacks TX checksum offloads; virtual devices have none, and nothing on a local loop verifies checksums. - README.md / src/apps/machnet/README.md: document the new field and the local workflow. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EFQ6Rh1j4r3i9QURDaUyXm
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Summary
Adds a self-contained way to develop and test Machnet locally on one Linux machine — no physical NIC, second VM, or cloud setup — by running the stack on a pair of DPDK virtual devices (
net_vhost+virtio_user) wired back-to-back over a unix socket.examples/local_vhost_test.sh— one-command local experiment: starts the Machnet daemon on the vhost pair, then runs the existinghello_worldserver (10.66.0.1) and client (10.66.0.2) and asserts the message crosses the loop (ARP, handshake, data transfer). Heavily commented so it doubles as local-dev documentation.examples/local_vhost_config.json— the two-interface config for the loop.machnet_config— new optional per-interface"vdev"key, passed to DPDK as--vdev(plus--no-pciwhen no physical ports are configured). vdev args are sorted so DPDK port ids — and hence thenet_vhostMAC, which is derived from the port id (56:48:4f:53:54:<port id>) — are deterministic across runs.pmd.cc— ports lacking TX checksum offloads now fall back to a basic ethernet configuration with a loud warning instead ofLOG(FATAL). Virtual devices have no checksum offloads; nothing on a local loop verifies checksums, so this is safe for the intended use and keeps the fatal-by-default spirit via the warning.vdevfield docs.Testing
bash -non the script and JSON validation pass.sudo examples/local_vhost_test.shbefore undrafting. Known risk to verify: thenet_vhostPMD MAC assumption (56:48:4f:53:54:00for port 0) — the script's comments explain how to reconcile against the[PMDPORT]log lines if it differs.🤖 Generated with Claude Code
https://claude.ai/code/session_01EFQ6Rh1j4r3i9QURDaUyXm