control_server: fix infinite loop in router_conns aggregation — use read-only head->next traversal instead of get/put

src/control_server.c

@@ -1175,8 +1175,8 @@ static void send_metrics(struct control_server* server, struct control_client* c
     /* Fill router congestion metrics — aggregate over all router_conns */
     memset(&rsp->router, 0, sizeof(rsp->router));
     if (instance->router_conns) {
-        struct ll_entry* re;
-        while ((re = queue_data_get(instance->router_conns)) != NULL) {
+        struct ll_entry* re = instance->router_conns->head;
+        while (re) {
             struct ETCP_ROUTER_CONN* rc = (struct ETCP_ROUTER_CONN*)re;
             rsp->router.total_inflight += (uint32_t)(rc->tx_seq - rc->tx_acked);
             if (rc->send_q) rsp->router.total_send_q += (uint32_t)queue_entry_count(rc->send_q);
@@ -1190,7 +1190,7 @@ static void send_metrics(struct control_server* server, struct control_client* c
             rsp->router.oob_dropped   += rc->c_oob_dropped;
             rsp->router.stale_ack     += rc->c_stale_ack;
             rsp->router.sign_fail     += rc->c_sign_fail;
-            queue_data_put_with_index(instance->router_conns, re);
+            re = re->next;
         }
         rsp->router.total_conns = (uint32_t)queue_entry_count(instance->router_conns);
     }