route_node: refactor NODEINFO — separate protocol/memory structs, linked lists with memory_pool

- NODEINFO_MSG (protocol, packed): added flags byte + group_id field
- NODEINFO (memory): ref_count, linked list heads instead of inline arrays
- NODEINFO_ROUTES: separate struct with linked list subnet heads
- NODEINFO_Q: node*, routes*, tranzit_data*, hop_list* as separate mallocs
- 6 memory_pools in ROUTE_BGP for NI_* linked list items
- ni_list_count() universal counter via _ni_head cast
- nodeinfo_serialize/deserialize for protocol <-> memory conversion
- NODEINFO_FLAG_SEND_SUBNETS controls subnet data in protocol
- group_id defaults: utun=NODEINFO_GROUP_UTUN(1) with subnets

Fixes:
- deserialization: data+2 instead of data+sizeof(BGP_NODEINFO_PACKET)
- memset: start after ll_entry to preserve ll.size
- hop_src: subtract hop_count*8 to point at correct dynamic offset
- same-ver branch: remove_path(conn) instead of remove_path_by_hop(peer)
- double-free in route_bgp_remove_conn/process_withdraw
- conn_mgr_add_alien_node: rewritten for new structures
- all test files updated for new API

src/control_server.c

@@ -1386,19 +1386,20 @@ static struct ETCP_CONN* find_connection_by_peer_id(struct UTUN_INSTANCE* instan
  * ============================================================================ */
 
 static void send_single_node_info(struct control_server* server, struct control_client* client, struct NODEINFO_Q* nq) {
-    int dyn = nodeinfo_dyn_size(&nq->node);
-    size_t np_size = sizeof(struct etcpmon_msg_header) + 2 + sizeof(struct NODEINFO) + dyn;
+    if (!server || !nq || !nq->node) return;
+    uint8_t buf[8192];
+    int ser_len = nodeinfo_serialize(server->instance->bgp, nq, buf + 2, sizeof(buf) - 2);
+    if (ser_len < 0) { DEBUG_ERROR(DEBUG_CATEGORY_CONTROL, "Failed to serialize node info"); return; }
+    buf[0] = CTRL_BGP_CMD; buf[1] = CTRL_BGP_SUBCMD;
+    size_t data_size = 2 + (size_t)ser_len;
 
+    size_t np_size = sizeof(struct etcpmon_msg_header) + data_size;
     uint8_t* buffer = (uint8_t*)u_malloc(np_size);
     if (!buffer) { DEBUG_ERROR(DEBUG_CATEGORY_CONTROL, "Failed to allocate node info buffer"); return; }
 
     struct etcpmon_msg_header* hdr = (struct etcpmon_msg_header*)buffer;
-    etcpmon_build_header(hdr, 2 + sizeof(struct NODEINFO) + dyn, ETCPMON_RSP_NODE_INFO, 0);
-
-    uint8_t* pay = buffer + sizeof(*hdr);
-    pay[0] = CTRL_BGP_CMD; pay[1] = CTRL_BGP_SUBCMD;
-    memcpy(pay + 2, &nq->node, sizeof(struct NODEINFO));
-    memcpy(pay + 2 + sizeof(struct NODEINFO), (uint8_t*)&nq->node + sizeof(struct NODEINFO), dyn);
+    etcpmon_build_header(hdr, (uint16_t)data_size, ETCPMON_RSP_NODE_INFO, 0);
+    memcpy(buffer + sizeof(*hdr), buf, data_size);
 
     control_client_send(server, client, buffer, (uint16_t)np_size);
 }