ouroboros/src/lib/shm_rbuff.c, branch master

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: Call mlock() on the shared memory buffers

2026-01-19T07:31:30+00:00

This prevents them from swapping to disk and killing performance. It also enhances security a little bit by reducing the risk of sensitive (even encrypted) data being paged out and captured. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Refactor rbuff

2026-01-07T13:33:47+00:00

Renames the macros and adds functions for handling the robust mutexes to reduce the preprocessor invasions. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Remove the not-so lockless rbuff_ll

2026-01-07T13:33:39+00:00

The "lockless" rbuff was mixing paradigms as it still has mutexes and condvars to avoid spinning on blocking behaviour. This was a bad idea. We'll add proper lockless implementations later. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

irmd: Revise IRMd internals

2024-02-19T10:49:07+00:00

This is a full revision of the IRMd internal implementation. The registry is now a proper subcomponent managing its own internal lock (a single mutex). Some tests are added for the registry and its data structures. Some macros for tests are added in . Flow allocation is now more symmetric between the client side (alloc) and server size (accept). Each will create a flow in pending state (ALLOC_PENDING/ACCEPT_PENDING) that is potentially fulfilled by an IPCP using respond_alloc and respond_accept primitives. Deallocation is split in flow_dealloc (application side) and ipcp_flow_dealloc (IPCP side) to get the flow in DEALLOC_PENDING and DEALLOCATED state. Cleanup of failed flow allocation is now properly handled instead of relying on the sanitizer thread. The new sanitizer only needs to monitor crashed processes. On shutdown, the IRMd will now detect hanging processes and SIGKILL them and clean up their fuse mountpoints if needed. A lot of other things have been cleaned up and shuffled around a bit. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

build: Update licenses to 2024

2024-01-13T09:20:14+00:00

Slow but steady. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Fix lengths of shared memory objects

2023-08-23T11:09:10+00:00

Seems like all shared memory objects were truncated to a size that came up a byte short. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

2023-02-13T20:10:10+00:00

2022 was a rather slow year... Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

2022-04-03T16:01:02+00:00

Growing pains. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Flag all flows down as the IRMd exits

2022-03-03T11:05:57+00:00

On exit of the IRMd all flows will now be flagged as down, so external applications will not hang anymore. Note: reads keep work from flows that are down until there are no more remaining packets in the buffer, but no more packets can be written. When the RIB is used, the external application may exit a bit later than the IRMd, so I added a brief sleep before the IRMd tries to remove the fuse main directory. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders