wip

Author: pavel-kirienko

AGENTS.md

@@ -19,9 +19,11 @@ Keep code compact and add brief comments before non-obvious logic.
 
 Treat warnings as errors and keep compatibility with strict warning flags.
 
+**FORCE PUSH MUST NEVER BE USED**. The git history is sacrosanct and must not be rewritten. If you need to undo a change, make a new commit.
+
 For agent-authored commits, set `GIT_AUTHOR_NAME="Agent"` and `GIT_COMMITTER_NAME="Agent"`.
 
-**FORCE PUSH MUST NEVER BE USED**. The git history is sacrosanct and must not be rewritten. If you need to undo a change, make a new commit.
+The build system will reject code that is not clang-formatted; use build target `format` to invoke clang-format.
 
 ## Adversarial validation and verification
 

libcanard/canard.c

@@ -1280,8 +1280,9 @@ static canard_tree_t* rx_session_factory(void* const user)
     FOREACH_SLOT (i) {
         ses->slots[i] = NULL;
     }
-    ses->owner   = ctx->owner;
-    ses->node_id = ctx->node_id;
+    ses->last_admitted_start_ts = BIG_BANG;
+    ses->owner                  = ctx->owner;
+    ses->node_id                = ctx->node_id;
     enlist_tail(&ctx->owner->owner->rx.list_session_by_animation, &ses->list_animation);
     return &ses->index;
 }
@@ -1356,16 +1357,15 @@ static bool rx_session_update(canard_subscription_t* const sub,
 
     // Frame admittance state machine. A highly complex piece, redesigned after v4 to support priority preemption.
     // TID forward difference illustration: f(2,3)==31, f(2,2)==0, f(2,1)==1
-    const bool tid_new = rx_transfer_id_forward_difference(ses->last_admitted_transfer_id, frame->transfer_id) > 1;
-    const canard_us_t timed_out = (ts - ses->last_admitted_start_ts) > ses->owner->transfer_id_timeout;
-    bool              accept    = false;
+    const bool tid_new   = rx_transfer_id_forward_difference(ses->last_admitted_transfer_id, frame->transfer_id) > 1;
+    const bool timed_out = ts > (ses->last_admitted_start_ts + ses->owner->transfer_id_timeout);
+    bool       accept    = false;
+    const rx_slot_t* const slot = ses->slots[frame->priority];
     if (!frame->start) {
-        const rx_slot_t* const slot = ses->slots[frame->priority];
         accept = (slot != NULL) && (slot->transfer_id == frame->transfer_id) && (slot->iface_index == iface_index) &&
                  (slot->expected_toggle == frame->toggle);
     } else {
-        const rx_slot_t* const slot = ses->slots[frame->priority];
-        accept = (slot == NULL) || (slot->transfer_id != frame->transfer_id) || tid_new || timed_out; // --
+        accept = ((slot == NULL) || (slot->transfer_id != frame->transfer_id)) && (tid_new || timed_out);
     }
     if (!accept) {
         return true; // Frame not needed; not a failure to accept.
@@ -1374,8 +1374,6 @@ static bool rx_session_update(canard_subscription_t* const sub,
     // The frame must be accepted. If this is the start of a new transfer, we must update state.
     enlist_tail(&sub->owner->rx.list_session_by_animation, &ses->list_animation);
     if (frame->start) {
-        ses->last_admitted_start_ts    = ts;
-        ses->last_admitted_transfer_id = frame->transfer_id;
         rx_slot_destroy(sub, ses->slots[frame->priority]);
         ses->slots[frame->priority] = NULL;
         if (!frame->end) { // more frames to follow, must store in-progress state
@@ -1385,6 +1383,8 @@ static bool rx_session_update(canard_subscription_t* const sub,
                 return false;
             }
         }
+        ses->last_admitted_start_ts    = ts;
+        ses->last_admitted_transfer_id = frame->transfer_id;
     }
 
     // TODO acceptance