mirror of
https://github.com/jmcorgan/fips.git
synced 2026-08-04 22:04:37 +00:00
Johnathan Corgan
0a84a25db1
Carries the inbound max_peers admission-cap silent-drop work from
master across the IK→XX structural boundary.
On master (Noise IK), the gate fires at handle_msg1 after the peer's
identity is extracted from the IK msg1 payload, before Msg2 is built
and sent. Wire savings of Msg2 (~104 B) plus the responder crypto
per cap-denied attempt motivate the gate placement.
On next (Noise XX), peer identity is not learned until msg3, by
which point Msg1, Msg2, and Msg3 have all crossed the wire. The IK
gate's wire-savings rationale does not apply on XX. The equivalent
gate is placed in handle_msg3 after the peer's static-key + signature
verification (identity now known) and before promote_connection
(ActivePeer construction, peers_by_index insert, link transition).
The value on XX is local CPU / allocation savings and cleaner peer-
side semantics: no fake-promotion whose subsequent data frames fail
decryption on this side, replaced by a silent drop the peer's
existing auto-reconnect backoff handles cleanly.
Bypass logic is the same as the IK version: known-active peers
(reconnect / cross-connection / restart) and pending-outbound peers
skip the cap so admitting them doesn't grow peers.len(). The late
cap check inside promote_connection is intentionally retained as
defense-in-depth.
Cleanup ordering for the gate's silent-drop path corrects a latent
issue in the adjacent msg3-processing-failure path: our_index is
captured before the connection is removed so the allocator slot is
actually freed (the pre-existing path's get-after-remove returns
None, leaking the index).
The two IK-shaped unit tests at handle_msg1 are marked #[ignore] on
this branch with reason. Their wire-bytes discriminator ("Msg2 must
NOT be sent at cap") is structurally false on XX, and the XX-shaped
equivalents need full three-message-handshake test scaffolding that
isn't authored here. XX-adapted unit + integration test coverage for
the handle_msg3 gate is a follow-up.
CHANGELOG [Unreleased] entry adjusted to describe the handle_msg3
placement on this branch (preserving the master-side framing on the
mainline-merge half of the entry would have been misleading on this
branch).
Three conflicts auto-resolved: the structural handshake.rs span
(~253 lines, IK identity-tied logic discarded on this branch's XX
msg1 path), and three textual ci-local.sh conflicts (admission-cap
suite list / dispatch added alongside the existing mixed-profile
suite list / dispatch).