ouroboros/src/lib, branch 0.24.0

ipcpd: Rework congestion avoidance

2026-07-19T09:44:36+00:00

Congestion avoidance is a property of the layer, orthogonal to ARQ and to flow control: FRCP retransmits and lets the peer pace the sender, per flow, end-to-end; the IPCP paces path aggregates. Each signal means one thing: a loss triggers a retransmission, a mark means congestion, the peer window means a slow receiver. Every flow is paced by the same rate law whatever its QoS, so a greedy raw sender shares a bottleneck fairly with a reliable stream. The unit of control is the (destination address, QoS cube) aggregate: all flows toward that destination share one controller and one rate; a start-time fair-queuing pacer divides the rate across them by deadline instead of blocking the send path, and a new flow rides the aggregate's estimates at its current rate, with no probing of its own. Slow start runs once per aggregate. The congestion signal is a multi-bit magnitude: forwarders mark packets with their standing queue depth, MAX-combined across hops, so a packet carries the deepest queue on its path. The receiver feeds back a time-integral mean over a window that adapts to the flow's byte rate, measuring a slow flow with the same fidelity as a fast one. The sender runs AIMD scaled by elapsed wall-clock time, which makes the steady-state allocation RTT-independent. The PCI gains one byte: the path capacity as a quarter-log2 code. Forwarders estimate their egress rate from busy-period drain and MIN-stamp the byte, the receiver returns the window minimum with its feedback, and the sender scales its rate floor and additive slope to the bottleneck (C / 32). A deep cut implies a backlogged bottleneck and a backlogged bottleneck advertises its capacity, so the scaled floor is live exactly when recovery needs it: the probe heals a halving in seconds at any link rate, and the floor bounds the deepest hole to a factor 32 below the bottleneck. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Whitespace cleanup in dev and frct

2026-07-19T09:44:35+00:00

Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Fix crypt_test without crypto backend

2026-07-19T09:44:35+00:00

Creating a context without OpenSSL fails (returns NULL) after adding the key rotation logic (requires HKDF). Assert instead that context creation returns NULL without OpenSSL. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Fix locking on flow read

2026-07-08T09:02:24+00:00

Reading a deallocated flow could cause an assert on a negative id. The raw-flow path now holds proc.lock across flow_rx_spb rather than dropping it first, and the FRCT loop no longer releases and reacquires the lock on every iteration. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Prefer writers on the proc flow lock

2026-07-08T09:02:24+00:00

FRCT readers hold proc.lock in a rdlock loop and could starve a pending flow accept waiting for the wrlock. Initialise the lock with the writer-nonrecursive kind on Linux with glibc, so writers are not indefinitely delayed. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Clean up on cancelled blocking read

2026-07-08T09:02:24+00:00

Cancelling a thread that was blocked in ssm_rbuff_read_b/write_b didn't clean up the n_users reference. If it was in flow_rx_one it didn't unlock the process lock. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Separate rekey replay from epoch conflict

2026-07-08T09:02:24+00:00

keyrot_rekey() treated any re-key attempt against a live epoch (current or previous) the same way, whether the offered root key matched the live one (a replay) or was genuinely different (a conflict). Compare the offered key against the live batch's root and return -EREPLAY for a match, keeping -1/-ECRYPT for an actual conflict, so callers can handle replayed re-keys distinctly from real ones. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Harden crypto unit tests

2026-07-08T09:02:23+00:00

Stop the non-OpenSSL runners from masking a real failure as SKIP by only downgrading to SKIP if they passed. Fix a stray call that ran test_kex_dhe_wrong_algo in the skip branch. Fix double free + free of an uninitialised pointer in test_store_add. Test that a KDF- less derive must fail. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Reject re-key to a live epoch

2026-07-08T09:02:23+00:00

A re-key epoch arrives from the peer, so we need to reject duplicates to avoid two batches sharing a wire epoch with different keys. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

build: Fix OpenSSL version check for PQC

2026-07-08T09:02:12+00:00

ML-KEM, ML-DSA and SLH-DSA all landed in OpenSSL 3.5.0, not 3.4.0. ML-KEM+ML-DSA and SLH-DSA can be disabled by DISABLE_ML / DISABLE_SLH. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders