Packet Metadata - Where Are Thee?
summary
Proposal reuses XDP headroom and ships a bpf_dynptr indirection (merged for 6.8) to decouple metadata from skb->data, but still needs a new skb field to track metadata offset to survive L2 decap and tx headroom moves. Production uses a simple TLV bottom-up format and stashes metadata in BPF maps, passing TCP via a custom socket option and UDP via repurposed cmsg/mark (32‑bit limit). Remaining blockers: metadata through Rx path, clean Tx reservation, BPF_PROG_RUN testing gaps, and policy‑routing / kernel extraction hooks.
AI-written summary · about
chapters (6)
- 0:00Introduction to packet metadata
- 1:05Motivation and use cases
- 6:49Progress update on XDP metadata
- 18:29Lessons from production adoption
- 25:01Unsolved problems in metadata
- 28:59Q&A on metadata sizing and routing
related talks
22mExtending AF_XDP with hardware metadata
28mSafe sharing of the network with eBPF
33mXDP gaining access to NIC hardware hints via BTF
32mOverview of the BPF networking hooks and user experience in Meta
33mBringing packet queueing to XDP
32mMPTCP: Extending kernel functionality with eBPF and Netlink
32meBPF: BPF kernel infrastructure
38mTelecom Packet Processing and Correlation Engine Using DPDK