Netlink Payload Decoding Infrastructure for FreeBSD Tracing Tools

This project improves Netlink support in FreeBSD tracing tools by enabling structured decoding of Netlink message payloads. Currently, truss(1) shows raw hexadecimal output for Netlink calls, making it difficult to interpret structured Netlink messages used by subsystems such as pf . The project will implement decoding within libsysdecode by parsing Generic Netlink headers (genlmsghdr), safely iterating over Type-Length-Value (nlattr) attributes, and dispatching to family-specific decoders. Deliverables include Generic Netlink support, a bounds-safe TLV parsing engine, a modular dispatch framework, and at least one functional decoder (pf), enabling human-readable output and providing a scalable foundation for future Netlink decoding.