ouroboros/src/ipcpd/unicast/dt.c, branch 0.24.0

ipcpd: Remove mutex on DT stats

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

There was a bug where the flow's stat mutex was zero'd while held. Removed the mutex alltogether; use stamp != 0 as the validity guard of the flow stats while reading stats. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

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 unreachable code in dt_init

2026-07-19T09:44:30+00:00

With IPCP_FLOW_STATS disabled, the bmp_destroy() in the dt_init() failure handling was unreachable. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

ipcpd: Refactor dt stats

2026-06-03T06:02:34+00:00

Use relaxed atomics in hot path to bump stats via dt_stat_inc/dt_stat_load. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

ipcpd: Fully gate fa/dt RIB ops on IPCP_FLOW_STATS

2026-05-27T13:55:08+00:00

The previous shape registered no-op _rib_read / _rib_readdir / _rib_getattr handlers when IPCP_FLOW_STATS was off, and there was a bug where *buf was not set in the no-op causing free on an uninitialized pointer. IPCP_FLOW_STATS was referenced by config.h.in but the declaration was lost during the CMake refactor. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

ipcpd: Close dt stat_used race vs rib readdir

2026-05-27T13:55:08+00:00

The stat_used function updated dt.stat[fd].stamp under the per-stat mutex, released it, then took dt.lock wrlock to bump dt.n_flows. A concurrent dt_rib_readdir holding dt.lock rdlock between those two critical sections saw the new stamp but the old n_flows. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Use push/pop for ssm_pk_buff ops

2026-05-20T06:17:06+00:00

Renames the allocation for head/tail to push/pop instead of alloc/release as it's simpler and shorter. Took this approach insted of adopting the kernel's push/pull/put/trim. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Rename PROG_* config to PROC_*

2026-05-20T06:17:06+00:00

Per-process flow / fd / fqueue limits are properties of a process, not a program; align the naming. Mechanical rename of PROG_MAX_FLOWS, PROG_RES_FDS, and PROG_MAX_FQUEUES to PROC_*. 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

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

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