ouroboros/src/ipcpd/unicast/dir, 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

ipcpd: Fix NULL deref in DHT cleanup

2026-07-19T09:44:34+00:00

The dht_kv_find_node_rsp_msg function steals *contacts and NULLs it on success. When the subsequent msg->val allocation fails in dht_kv_find_value_rsp_msg(), the stolen contacts are freed along with the message, and do_dht_kv_find_value_req() is left with contacts == NULL while n_contacts is still positive: its fail_vals loop then dereferences NULL. Found by clang static analyzer. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

ipcpd: Store local names before DHT peering

2026-07-08T09:02:25+00:00

A name registered before the DHT had a peer stayed unpublished until it neared its expiry deadline. Make a never-stored local value (t_repl == 0) eligible for replication immediately, and flush replication once when the worker starts so such names are published as soon as the DHT is enrolled. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

ipcpd: Fix DHT bootstrap re-seeding

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

The bootstrap seeder reported success as soon as the query was sent. Only skip seeding once the peer is in a bucket, and return -EAGAIN until it actually appears so the caller keeps retrying rather than assuming bootstrap completed. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

ipcpd: Fix unused values in unicast IPCP

2026-02-22T15:04:16+00:00

Use the key in the store operation in the DHT, to avoid static analyzer seeing it as being set without being used in release builds. The length of the packet buffer is only used when tracking DT stats, so should be set within the IPCP_FLOW_STATS guard. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Add struct llist for lists tracking len

2026-02-18T06:58:21+00:00

The DHT uses a struct {struct list_head, size_t len} pattern, which is also useful in the registry and other places. Having a struct llist (defined in list.h) with consistent macros for addition/deletion etc removes a lot of duplication and boilerplate and reduces the risk of inconsistent updates. The list management is now a macro-only implementation. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

build: Update copyright to 2026

2026-02-18T06:54:56+00:00

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

build: Refactor CMake back to in-tree CMakeLists

2026-02-13T08:22:29+00:00

This moves the build definitions back to src/ subdirectories (CMakeLists.txt per component). Configuration and dependencies are kept out of tree. Configuration options are bundled into cmake/config/ modules. Dependencies are grouped by component (system/, crypt/, eth/, coverage/, etc.). It now consistently uses target-based commands (target_include_directories, target_link_libraries) instead of global include_directories(). Proper PRIVATE/PUBLIC visibility for executable link libraries. CONFIG_OUROBOROS_DEBUG now properly set based on being a valid debug config (not just checking the string name). It also adds OuroborosTargets export for find_package() support and CMake package config files (OuroborosConfig.cmake) for easier integration with CMake projects. The build logic now follows more idiomatic CMake practices with configuration separated from target definitions. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Replace rdrbuff with a proper slab allocator

2026-01-26T06:50:33+00:00

This is a first step towards the Secure Shared Memory (SSM) infrastructure for Ouroboros, which will allow proper resource separation for non-privileged processes. This replaces the rdrbuff (random-deletion ring buffer) PoC allocator with a sharded slab allocator for the packet buffer pool to avoid the head-of-line blocking behaviour of the rdrb and reduce lock contention in multi-process scenarios. Each size class contains multiple independent shards, allowing parallel allocations without blocking. - Configurable shard count per size class (default: 4, set via SSM_POOL_SHARDS in CMake). The configured number of blocks are spread over the number of shards. As an example: SSM_POOL_512_BLOCKS = 768 blocks total These 768 blocks are shared among 4 shards (not 768 × 4 = 3072 blocks) - Lazy block distribution: all blocks initially reside in shard 0 and naturally migrate to process-local shards upon first allocation and subsequent free operations - Fallback with work stealing: processes attempt allocation from their local shard (pid % SSM_POOL_SHARDS) first, then steal from other shards if local is exhausted, eliminating fragmentation while maintaining low contention - Round-robin condvar signaling: blocking allocations cycle through all shard condition variables to ensure fairness - Blocks freed to allocator's shard: uses allocator_pid to determine target shard, enabling natural load balancing as process allocation patterns stabilize over time Maintains existing robust mutex semantics including EOWNERDEAD handling for dead process recovery. Internal structures exposed in ssm.h for testing purposes. Adds some tests (pool_test, pool_sharding_test.c. etc) verifying lazy distribution, migration, fallback stealing, and multiprocess behavior. Updates the ring buffer (rbuff) to use relaxed/acquire/release ordering on atomic indices. The ring buffer requires the (robust) mutex to ensure cross-structure synchronization between pool buffer writes and ring buffer index publication. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Add post-quantum cryptography support

2026-01-19T07:29:29+00:00

This adds initial support for runtime-configurable encryption and post-quantum Key Encapsulation Mechanisms (KEMs) and authentication (ML-DSA). Supported key exchange algorithms: ECDH: prime256v1, secp384r1, secp521r1, X25519, X448 Finite Field DH: ffdhe2048, ffdhe3072, ffdhe4096 ML-KEM (FIPS 203): ML-KEM-512, ML-KEM-768, ML-KEM-1024 Hybrid KEMs: X25519MLKEM768, X448MLKEM1024 Supported ciphers: AEAD: aes-128-gcm, aes-192-gcm, aes-256-gcm, chacha20-poly1305 CTR: aes-128-ctr, aes-192-ctr, aes-256-ctr Supported HKDFs: sha256, sha384, sha512, sha3-256, sha3-384, sha3-512, blake2b512, blake2s256 Supported Digests for DSA: sha256, sha384, sha512, sha3-256, sha3-384, sha3-512, blake2b512, blake2s256 PQC support requires OpenSSL 3.4.0+ and is detected automatically via CMake. A DISABLE_PQC option allows building without PQC even when available. KEMs differ from traditional DH in that they require asymmetric roles: one party encapsulates to the other's public key. This creates a coordination problem during simultaneous reconnection attempts. The kem_mode configuration parameter resolves this by pre-assigning roles: kem_mode=server # Server encapsulates (1-RTT, full forward secrecy) kem_mode=client # Client encapsulates (0-RTT, cached server key) The enc.conf file format supports: kex= # Key exchange algorithm cipher= # Symmetric cipher kdf= # Key derivation function digest= # Digest for DSA kem_mode= # Server (default) or client none # Disable encryption The OAP protocol is extended to negotiate algorithms and exchange KEX data. All KEX messages are signed using existing authentication infrastructure for integrity and replay protection. Tests are split into base and _pqc variants to handle conditional PQC compilation (kex_test.c/kex_test_pqc.c, oap_test.c/oap_test_pqc.c). Bumped minimum required OpenSSL version for encryption to 3.0 (required for HKDF API). 1.1.1 is long time EOL. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders