GUI: add active timeouts and busy memory blocks counters

- Add timeout_heap_get_size() to get active timer count
- Add global counters in memory_pool: g_total_free and g_total_allocated
- Simplify busy memory calculation to single formula:
  busy = memory_pool_get_total_allocated() - memory_pool_get_total_free_blocks()
- Add new IDC_EDIT_ACTIVE_TIMEOUTS and IDC_EDIT_BUSY_MEMORY to GUI

src/control_server.c

@@ -14,6 +14,8 @@
 #include "pkt_normalizer.h"
 #include "../tools/etcpmon/etcpmon_protocol.h"
 #include "../lib/u_async.h"
+#include "../lib/timeout_heap.h"
+#include "../lib/memory_pool.h"
 #include "../lib/debug_config.h"
 #include "../lib/mem.h"
 #include "../lib/ll_queue.h"
@@ -971,6 +973,15 @@ static void send_metrics(struct control_server* server, struct control_client* c
     for (int i = 0; i < 8; i++) {
         rsp->etcp.debug[i] = conn->debug[i];
     }
+
+    /* System resources */
+    if (instance->ua && instance->ua->timeout_heap) {
+        rsp->etcp.active_timeouts = (uint32_t)timeout_heap_get_size(instance->ua->timeout_heap);
+    } else {
+        rsp->etcp.active_timeouts = 0;
+    }
+
+    rsp->etcp.busy_memory_blocks = (uint32_t)(memory_pool_get_total_allocated() - memory_pool_get_total_free_blocks());
     
     /* Fill TUN metrics */
     if (instance->tun) {