Files
fips/docs/design
Johnathan Corgan 4a1d583653 fix(gateway): read conntrack over netlink when the proc file is absent
A kernel built without CONFIG_NF_CONNTRACK_PROCFS, such as Ubuntu's, has
no /proc/net/nf_conntrack. The gateway then counted zero sessions for
every mapping, so a mapping still carrying traffic was reclaimed on its
TTL and grace period alone.

When the proc file is absent, the gateway now dumps the IPv6 conntrack
table over NETLINK_NETFILTER, the request conntrack -L makes, and counts
each entry once per distinct destination, the same rule the proc parser
applies. The choice is made on every read, because the proc file appears
only once nf_conntrack is loaded. Any other proc error is still reported
without falling back. When both sources fail, the per-tick warning
carries the netlink error, and the startup line names both errors.

The dump uses netlink-packet-netfilter 0.3, the release built on the
netlink-packet-core 0.8 that rtnetlink already uses.

The gateway suite now expects the netlink source line when the
container has no proc file, and checks that the gateway counts the
session left by the HTTP request through the first virtual IP.
2026-09-19 03:54:00 +00:00
..
2026-08-30 10:42:59 +00:00
2026-08-30 10:42:59 +00:00

FIPS Design

Architectural and protocol-level explanations for FIPS — the why and the how behind the wire and the system. For wire formats and configuration keys, see reference/. For task recipes, see how-to/. For end-to-end lessons, see tutorials/.

Reading Order

Start with fips-concepts.md for the novice-friendly framing of what FIPS is and why, then move to fips-architecture.md for the protocol stack, identity model, and two-layer encryption walkthrough. From there, follow the protocol stack from bottom to top. After the stack, fips-mesh-operation.md explains how the pieces work together at runtime. Cross-cutting and supporting documents cover specific subsystems in detail.

Foundations

Document Description
fips-concepts.md What FIPS is, why it exists, mental model
fips-architecture.md Protocol stack, identity, two-layer encryption
fips-prior-work.md Designs and protocols FIPS builds on

Protocol Stack

Document Description
fips-transport-layer.md Transport layer: datagram delivery over arbitrary media
fips-mesh-layer.md FIPS Mesh Protocol (FMP): peer authentication, link encryption, forwarding
fips-session-layer.md FIPS Session Protocol (FSP): end-to-end encryption, sessions
fips-ipv6-adapter.md IPv6 adaptation: TUN interface, DNS, MTU enforcement
fips-native-api.md Native datagram API: pubkey-addressed flows over FSP, and what it is instead of the TUN path

Cross-Cutting

Document Description
fips-mmp.md Metrics Measurement Protocol (link + session)
fips-mtu.md Path MTU model, encapsulation overhead, PMTUD
fips-security.md fips0 interface threat model and default-deny baseline

Mesh Behavior

Document Description
fips-mesh-operation.md How the mesh operates: routing, discovery, error recovery
fips-nostr-discovery.md Optional Nostr-mediated peer discovery and UDP NAT hole-punch
port-advertisement-and-nat-traversal.md Nostr-signaled port advertisement and UDP NAT-traversal protocol; generic, with FIPS as an example implementation

Deeper Dives

Document Description
fips-spanning-tree.md Spanning tree algorithms: root discovery, parent selection, coordinates
fips-bloom-filters.md Bloom filter properties: FPR analysis, size classes, split-horizon
spanning-tree-dynamics.md Spanning tree walkthroughs: convergence scenarios, worked examples

Adjacent Components

Document Description
fips-gateway.md fips-gateway service: outbound (LAN-to-mesh) DNS-proxy + virtual-IP NAT and inbound (mesh-to-LAN) port-forwarding, sharing one nftables table