test: 5 new router unit tests — RST, restart, sess_id

test_rst_flag: inject ROUTER_FLAG_RST → rconn destroyed, service notified
test_client_restart: pump random data → inject START → restart detected
test_sess_id_change: pump sess_id=0 → inject sess_id=1+START → detected
test_sess_id_wrap: pump sess_id=3, peer_sess_id=3 → inject sess_id=0+START → wrap detected
test_server_reinit: reinit router → new rconn start_sent=0, sess_id=0

inject() extended with uint8_t flags parameter.
pump_data helper for random data injection.
test_handler tracks g_notify_count for close/restart notifications.

fix: etcp_router_recv_cb — return after RST flag to avoid NULL rconn deref

src/etcp_router.c

@@ -396,7 +396,8 @@ static void etcp_router_recv_cb(struct ETCP_CONN* conn, struct ll_entry* entry)
                            "router: RST from %016llx svc_id=%u",
                            (unsigned long long)hdr->src_node_id, hdr->svc_id);
                 router_close_and_notify(rconn);
-                rconn = NULL;
+                queue_dgram_free(entry); queue_entry_free(entry);
+                return;
             }
         }
 

tests/test_etcp_router_unit.c

@@ -31,11 +31,13 @@ static struct {
     uint8_t marker;
 } rx;
 
+static int g_notify_count = 0;
+
 static void test_handler(struct ETCP_CONN* conn, struct ll_entry* entry) {
     (void)conn;
     if (!entry || !entry->dgram || entry->len < 2) {
-        if (entry) { queue_entry_free(entry); queue_dgram_free(entry); }
+        g_notify_count++;
-        rx.errors++;
+        if (entry) { queue_dgram_free(entry); queue_entry_free(entry); }
         return;
     }
     if (entry->dgram[1] != rx.marker) { rx.errors++; } else { rx.delivered++; rx.last_seq = rx.expected_seq; rx.expected_seq++; }
@@ -52,7 +54,7 @@ static struct ETCP_CONN fake_conn;
 
 static void inject(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
                    uint64_t src, uint8_t svc_id, uint32_t seq,
-                   const uint8_t* pl, size_t pl_len, int is_ack) {
+                   const uint8_t* pl, size_t pl_len, int is_ack, uint8_t flags) {
     struct SVC_ROUTE_HDR hdr;
     memset(&hdr, 0, sizeof(hdr));
     hdr.cmd         = ETCP_ID_SVC_ROUTE;
@@ -60,6 +62,7 @@ static void inject(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
     hdr.src_node_id = src;
     hdr.seq         = seq;
     hdr.svc_id      = svc_id;
+    hdr.flags       = flags;
 
     size_t total = SVC_ROUTE_HDR_SIZE + (is_ack ? 0 : pl_len);
     struct ll_entry* e = queue_entry_new(0);
@@ -250,9 +253,9 @@ static int test_in_order(void) {
 
     rx_reset(0xAA);
     uint8_t data[] = { TEST_SVC_ID, 0xAA, 0 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0, 0);
 
     if (rx.delivered != 3) FAIL("delivered != 3");
     if (rx.errors != 0) FAIL("errors != 0");
@@ -273,14 +276,14 @@ static int test_out_of_order(void) {
 
     rx_reset(0xBB);
     uint8_t data[] = { TEST_SVC_ID, 0xBB, 0 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
     if (rx.delivered != 1) FAIL("after seq 0: delivered != 1");
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 3, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 3, data + 1, 2, 0, 0);
     if (rx.delivered != 1) FAIL("after seq 2,3: still delivered != 1 (gap at 1)");
 
     // Fill the gap
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
     if (rx.delivered != 4) FAIL("after seq 1 fill: delivered != 4");
     if (rx.errors   != 0) FAIL("errors != 0");
     if (c->rx_seq   != 4) FAIL("rx_seq != 4");
@@ -300,9 +303,9 @@ static int test_duplicate_same(void) {
 
     rx_reset(0xCC);
     uint8_t data[] = { TEST_SVC_ID, 0xCC, 0 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0); // dup
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0); // dup
 
     if (rx.delivered != 2) FAIL("delivered != 2 (dup dropped)");
     if (c->rx_seq   != 2) FAIL("rx_seq != 2");
@@ -322,10 +325,10 @@ static int test_duplicate_past(void) {
 
     rx_reset(0xDD);
     uint8_t data[] = { TEST_SVC_ID, 0xDD, 0 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
     if (rx.delivered != 2) FAIL("delivered != 2");
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0); // past
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0); // past
 
     if (rx.delivered != 2) FAIL("delivered != 2 (past dup dropped)");
     if (c->rx_seq   != 2) FAIL("rx_seq != 2");
@@ -346,7 +349,7 @@ static int test_out_of_bounds(void) {
     rx_reset(0xEE);
     uint8_t data[] = { TEST_SVC_ID, 0xEE, 0 };
     uint32_t bad_seq = ROUTER_MAX_INFLIGHT + 2;
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, bad_seq, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, bad_seq, data + 1, 2, 0, 0);
 
     if (rx.delivered != 0) FAIL("out-of-bounds delivered");
     if (c->rx_seq   != 0) FAIL("rx_seq changed on bounds drop");
@@ -368,10 +371,10 @@ static int test_circular_wrap(void) {
     rx_reset(0x11);
     rx.expected_seq = 0xFFFFFFFE;
     uint8_t data[] = { TEST_SVC_ID, 0x11, 0 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFE, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFE, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFF, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFF, data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0,            data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0,            data + 1, 2, 0, 0);
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1,            data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1,            data + 1, 2, 0, 0);
 
     if (rx.delivered != 4) FAIL("delivered != 4 (wrap)");
     if (c->rx_seq   != 2) FAIL("rx_seq != 2 after wrap (wrapped)");
@@ -391,7 +394,7 @@ static int test_data_integrity(void) {
 
     rx_reset(0x77);
     uint8_t payload[10] = { 0x77, 0xA1, 0xB2, 0xC3, 0xD4, 0xE5, 0xF6, 0x07, 0x18, 0x29 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, payload, 10, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, payload, 10, 0, 0);
 
     if (rx.delivered != 1) FAIL("delivered != 1");
     if (rx.errors   != 0) FAIL("data mismatch");
@@ -411,7 +414,7 @@ static int test_ack_receive(void) {
 
     rx_reset(0x00);
     // Send ACK: is_ack=1, seq=7 means remote has rx_seq=7
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 7, NULL, 0, 1);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 7, NULL, 0, 1, 0);
 
     if (c->tx_acked != 7)      FAIL("tx_acked not updated from ACK");
     if (rx.delivered != 0)     FAIL("ACK delivered to handler (should not)");
@@ -434,7 +437,7 @@ static int test_ack_timer(void) {
 
     rx_reset(0x55);
     uint8_t data[] = { TEST_SVC_ID, 0x55, 0 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
 
     if (c->ack_timer == NULL && c->last_sent_ack_seq != 1) FAIL("ack not sent (no timer, no immediate)");
     if (c->ack_timer != NULL && c->last_sent_ack_seq != 0) FAIL("last_sent_ack_seq changed before timer fired");
@@ -513,7 +516,7 @@ static int test_timestamp(void) {
 
     rx_reset(0x99);
     uint8_t data[] = { TEST_SVC_ID, 0x99, 0 };
-    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0);
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
 
     if (c->last_dgram_ts == 0) FAIL("last_dgram_ts zero after data");
     // Cancel ack_timer
@@ -542,6 +545,143 @@ static int test_conn_send_no_bgp(void) {
     return 0;
 }
 
+// ======================== Helper: pump random data ========================
+static int pump_data(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
+                     uint8_t marker, int count, uint8_t flags) {
+    uint8_t data[] = { TEST_SVC_ID, marker, 0 };
+    for (int i = 0; i < count; i++)
+        inject(recv_cb, inst, TEST_REMOTE_NODE, TEST_SVC_ID, i, data + 1, 2, 0, flags);
+    return count;
+}
+
+// ======================== Restart/session tests ========================
+
+static int test_rst_flag(void) {
+    TEST("RST flag — rconn destroyed, service notified");
+    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
+    SETUP();
+    g_notify_count = 0;
+
+    int n = rand() % 10 + 1;
+    rx_reset(0xA1);
+    pump_data(recv_cb, &inst, 0xA1, n, 0);
+    if (rx.delivered != n) FAIL("initial pump failed");
+
+    uint8_t data[] = { TEST_SVC_ID, 0x01, 0 };
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, n, data + 1, 2, 0, ROUTER_FLAG_RST);
+    if (g_notify_count != 1) FAIL("RST should notify service");
+
+    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
+    if (!c) FAIL("new rconn should exist");
+    etcp_router_conn_close(c);
+
+    TEARDOWN();
+    PASS();
+    return 0;
+}
+
+static int test_client_restart(void) {
+    TEST("client restart — START flag detected after random data");
+    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
+    SETUP();
+    g_notify_count = 0;
+
+    int n = rand() % 10 + 1;
+    rx_reset(0xB1);
+    pump_data(recv_cb, &inst, 0xB1, n, 0);
+    if (rx.delivered != n) FAIL("initial pump failed");
+
+    rx_reset(0xB2);
+    uint8_t data[] = { TEST_SVC_ID, 0xB2, 0 };
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
+    if (g_notify_count != 1) FAIL("restart not notified");
+    if (rx.delivered < 1) FAIL("data after restart not delivered");
+
+    TEARDOWN();
+    PASS();
+    return 0;
+}
+
+static int test_sess_id_change(void) {
+    TEST("sess_id change — 0→1 with START triggers restart");
+    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
+    SETUP();
+    g_notify_count = 0;
+
+    int n = rand() % 10 + 1;
+    rx_reset(0xC1);
+    pump_data(recv_cb, &inst, 0xC1, n, 0);
+    if (rx.delivered != n) FAIL("initial pump failed");
+
+    rx_reset(0xC2);
+    uint8_t data[] = { TEST_SVC_ID, 0xC2, 0 };
+    uint8_t f = (1 << ROUTER_SESS_ID_SHIFT) | ROUTER_FLAG_START;
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, f);
+    if (g_notify_count != 1) FAIL("restart not notified");
+    if (rx.delivered < 1) FAIL("data after restart not delivered");
+
+    TEARDOWN();
+    PASS();
+    return 0;
+}
+
+static int test_sess_id_wrap(void) {
+    TEST("sess_id wrap — 3→0 with START triggers restart");
+    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
+    SETUP();
+    g_notify_count = 0;
+
+    int n = rand() % 10 + 1;
+    uint8_t f3 = (3 << ROUTER_SESS_ID_SHIFT);
+    rx_reset(0xD1);
+
+    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
+    if (!c) FAIL("rconn not found");
+    c->peer_sess_id = 3;
+
+    pump_data(recv_cb, &inst, 0xD1, n, f3);
+    if (rx.delivered != n) FAIL("initial pump failed");
+
+    rx_reset(0xD2);
+    g_notify_count = 0;
+    uint8_t data[] = { TEST_SVC_ID, 0xD2, 0 };
+    uint8_t f0 = (0 << ROUTER_SESS_ID_SHIFT) | ROUTER_FLAG_START;
+    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, f0);
+    if (g_notify_count != 1) FAIL("restart not notified on wrap");
+    if (rx.delivered < 1) FAIL("data after wrap not delivered");
+
+    TEARDOWN();
+    PASS();
+    return 0;
+}
+
+static int test_server_reinit(void) {
+    TEST("server reinit — new rconn gets start_sent=0 sess_id=0");
+    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
+    SETUP();
+
+    int n = rand() % 10 + 1;
+    pump_data(recv_cb, &inst, 0xE1, n, 0);
+
+    etcp_router_destroy(&inst);
+    memset(&inst.api_bindings, 0, sizeof(inst.api_bindings));
+    memset(&inst.router_bindings, 0, sizeof(inst.router_bindings));
+    if (etcp_router_init(&inst) != 0) FAIL("reinit failed");
+    etcp_router_bind(&inst, TEST_SVC_ID, test_handler);
+    recv_cb = inst.api_bindings.callbacks[ETCP_ID_SVC_ROUTE];
+    if (!recv_cb) FAIL("recv_cb not bound");
+
+    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
+    if (!c) FAIL("rconn after reinit");
+    if (c->start_sent != 0) FAIL("start_sent != 0 after reinit");
+    if (c->sess_id != 0) FAIL("sess_id != 0 after reinit");
+
+    etcp_router_conn_close(c);
+    TEARDOWN();
+    PASS();
+    return 0;
+}
+
 // ======================== Main ========================
 int main(void) {
     // Run all tests
@@ -563,6 +703,11 @@ int main(void) {
     test_loopback();
     test_timestamp();
     test_conn_send_no_bgp();
+    test_rst_flag();
+    test_client_restart();
+    test_sess_id_change();
+    test_sess_id_wrap();
+    test_server_reinit();
 
     printf("\n=== Results: %d/%d passed, %d failed ===\n", test_passed, test_total, test_failed);
     return test_failed > 0 ? 1 : 0;