From a7ecee01f5dbab0d2a72fc6d12247233a2e7695d Mon Sep 17 00:00:00 2001
From: Evgeny <me@jeka.su>
Date: Wed, 15 Jul 2026 19:56:47 +0300
Subject: [PATCH] etcp: replace connections linked-list with indexed ll_queue,
 add state/ref_count lifecycle
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- Remove ETCP_CONN.next linked-list, UTUN_INSTANCE.connections list/count
- Unified connections in single ll_queue indexed by peer_node_id (0=pending)
- struct conn_queue_entry { peer_node_id, conn* } for uniform queue data
- Connection lifecycle via etcp.c: create→pending, conn_ready→indexed, close→detach+deferred free
- Close split: phase1 detach from external world, phase2 deferred via uasync_call_soon
- etcp_conn_set_peer_node_id: reindex on ID change (WARN)
- etcp_conn_ref_take/free: blocking close until refcount returns to 0
- Remove chat_connections — use unified connections queue directly
- Update all iteration/search patterns across 40 files (src + tests + chatgui)
---
 src/control_server.c                         |  30 ++-
 src/db_sync.c                                |  47 ++--
 src/etcp.c                                   | 224 +++++++++++++------
 src/etcp.h                                   |  33 ++-
 src/etcp_connect.c                           |  33 +--
 src/etcp_connections.c                       |  49 ++--
 src/etcp_dump.c                              |  15 +-
 src/ntp_node_time.c                          |   7 +-
 src/topo_group.c                             |   6 +-
 src/utun_instance.c                          |  49 ++--
 src/utun_instance.h                          |  12 +-
 tests/bbr_integration/test_bbr_integration.c | 101 +++++----
 tests/test_bgp_route_exchange.c              |  23 +-
 tests/test_bgp_triangle.c                    |  22 +-
 tests/test_conn_mgr.c                        |   7 +-
 tests/test_db_sync.c                         |   7 +-
 tests/test_etcp_100_packets.c                |  18 +-
 tests/test_etcp_api.c                        |  14 +-
 tests/test_etcp_congestion.c                 |  16 +-
 tests/test_etcp_connect.c                    |   7 +-
 tests/test_etcp_dummynet.c                   |  10 +-
 tests/test_etcp_ping.c                       |  18 +-
 tests/test_etcp_reconnect.c                  |  29 +--
 tests/test_etcp_reinit_inflight.c            |  28 ++-
 tests/test_etcp_router.c                     |   8 +-
 tests/test_etcp_router_reconnect.c           |   7 +-
 tests/test_etcp_simple_traffic.c             |  14 +-
 tests/test_etcp_two_instances.c              |  16 +-
 tests/test_icmp_proxy.c                      |  10 +-
 tests/test_ipv6_sockets.c                    |  10 +-
 tests/test_nat_detection.c                   |  41 ++--
 tests/test_nat_transport.c                   |  13 +-
 tests/test_pkt_normalizer_etcp.c             |  20 +-
 tests/test_route_ping.c                      |  20 +-
 tests/test_socks_http_proxy.c                |   9 +-
 tests/test_stcp_traffic.c                    |   7 +-
 tests/test_tcp_proxy_remote.c                |  10 +-
 tests/test_udp_proxy.c                       |  10 +-
 tools/chatgui/transport/chat_core.c          |  17 +-
 tools/chatgui/transport/chat_sync.c          |  80 ++++---
 40 files changed, 649 insertions(+), 448 deletions(-)

diff --git a/src/control_server.c b/src/control_server.c
index 039db141..1c206492 100644
--- a/src/control_server.c
+++ b/src/control_server.c
@@ -885,10 +885,10 @@ static void send_conn_list(struct control_server* server, struct control_client*
     
     /* Count connections */
     uint8_t count = 0;
-    struct ETCP_CONN* conn = instance->connections;
-    while (conn && count < ETCPMON_MAX_CONNECTIONS) {
+    struct ll_entry* entry = instance->connections->head;
+    while (entry && count < ETCPMON_MAX_CONNECTIONS) {
         count++;
-        conn = conn->next;
+        entry = entry->next;
     }
     
     /* Build response */
@@ -909,12 +909,13 @@ static void send_conn_list(struct control_server* server, struct control_client*
     rsp->count = count;
     
     struct etcpmon_conn_info* info = (struct etcpmon_conn_info*)(buffer + sizeof(*hdr) + sizeof(*rsp));
-    conn = instance->connections;
-    for (uint8_t i = 0; i < count && conn; i++) {
-        info[i].peer_node_id = conn->peer_node_id;
-        strncpy(info[i].name, conn->log_name, ETCPMON_MAX_CONN_NAME - 1);
+    entry = instance->connections->head;
+    for (uint8_t i = 0; i < count && entry; i++) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        info[i].peer_node_id = ce->conn->peer_node_id;
+        strncpy(info[i].name, ce->conn->log_name, ETCPMON_MAX_CONN_NAME - 1);
         info[i].name[ETCPMON_MAX_CONN_NAME - 1] = '\0';
-        conn = conn->next;
+        entry = entry->next;
     }
     
     /* Log and send response */
@@ -1372,14 +1373,11 @@ static void send_debug_config(struct control_server* server, struct control_clie
 
 static struct ETCP_CONN* find_connection_by_peer_id(struct UTUN_INSTANCE* instance, 
                                                      uint64_t peer_id) {
-    struct ETCP_CONN* conn = instance->connections;
-    while (conn) {
-        if (conn->peer_node_id == peer_id) {
-            return conn;
-        }
-        conn = conn->next;
-    }
-    return NULL;
+    if (!instance || !instance->connections) return NULL;
+    struct ll_entry* e = queue_find_data_by_index(instance->connections, (const uint8_t*)&peer_id);
+    if (!e) return NULL;
+    struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+    return ce->conn;
 }
 
 /* ============================================================================
diff --git a/src/db_sync.c b/src/db_sync.c
index 32876ad2..681c96e4 100644
--- a/src/db_sync.c
+++ b/src/db_sync.c
@@ -488,9 +488,9 @@ static int db_sync_send_hash(struct DB_SYNC* db, uint64_t node_id,
     entry->len = plen + 9;
 
     struct ETCP_CONN* conn = NULL;
-    if (db->inst->chat_connections) {
-        struct ll_entry* e = queue_find_data_by_index(db->inst->chat_connections, (const uint8_t*)&node_id);
-        if (e) { struct { uint64_t node_id; struct ETCP_CONN* conn; }* ce = e->data; if (ce->conn->links_up) conn = ce->conn; }
+    {
+        struct ll_entry* e = queue_find_data_by_index(db->inst->connections, (const uint8_t*)&node_id);
+        if (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data; if (ce->conn->links_up) conn = ce->conn; }
     }
     if (!conn) {
         DEBUG_WARN(DEBUG_CATEGORY_DB_SYNC,
@@ -1430,11 +1430,16 @@ int db_sync_init(struct UTUN_INSTANCE* inst)
     etcp_set_new_conn_cbk(inst, db_sync_on_new_conn, NULL);
 
     // Attach to existing connections
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        etcp_conn_add_up_cbk(conn, db_sync_on_conn_up, NULL);
-        etcp_conn_add_down_cbk(conn, db_sync_on_conn_down, NULL);
-        conn = conn->next;
+    {
+        struct ll_entry* entry = inst->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            if (ce && ce->conn) {
+                etcp_conn_add_up_cbk(ce->conn, db_sync_on_conn_up, NULL);
+                etcp_conn_add_down_cbk(ce->conn, db_sync_on_conn_down, NULL);
+            }
+            entry = entry->next;
+        }
     }
 
     if (db->enabled)
@@ -1474,11 +1479,16 @@ void db_sync_destroy(struct UTUN_INSTANCE* inst)
     }
 
     // Detach from existing connections
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        etcp_conn_remove_up_cbk(conn, db_sync_on_conn_up, NULL);
-        etcp_conn_remove_down_cbk(conn, db_sync_on_conn_down, NULL);
-        conn = conn->next;
+    {
+        struct ll_entry* entry = inst->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            if (ce && ce->conn) {
+                etcp_conn_remove_up_cbk(ce->conn, db_sync_on_conn_up, NULL);
+                etcp_conn_remove_down_cbk(ce->conn, db_sync_on_conn_down, NULL);
+            }
+            entry = entry->next;
+        }
     }
 
     db_sqlite_close(db);
@@ -1579,11 +1589,12 @@ struct DB_SYNC_INSTANCE* db_sync_instance_add(struct UTUN_INSTANCE* inst,
 
     // Initiate sync with already connected peers
     {
-        struct ETCP_CONN* conn = inst->connections;
-        while (conn) {
-            uint64_t pid = conn->peer_node_id;
+        struct ll_entry* entry = inst->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            uint64_t pid = ce->conn->peer_node_id;
             if (pid != 0 && pid != inst->node_id
-                && conn->links_up > 0 && conn->initialized)
+                && ce->conn->links_up > 0 && ce->conn->initialized)
             {
                 struct SI_PEER* p = si_peer_add(si, pid);
                 if (p && p->synced == 0) {
@@ -1591,7 +1602,7 @@ struct DB_SYNC_INSTANCE* db_sync_instance_add(struct UTUN_INSTANCE* inst,
                     db_sync_initiate_sync(si, pid);
                 }
             }
-            conn = conn->next;
+            entry = entry->next;
         }
     }
 
diff --git a/src/etcp.c b/src/etcp.c
index 44775316..4e1357bf 100644
--- a/src/etcp.c
+++ b/src/etcp.c
@@ -44,6 +44,7 @@ static void input_send_q_cb(struct ll_queue* q, void* arg);
 static void wait_ack_cb(struct ll_queue* q, void* arg);
 static void send_ack_req_cb(struct ll_queue* q, void* arg);
 static void etcp_conn_process_send_queue(struct ETCP_CONN* etcp);
+static void etcp_connection_free_deferred(void* arg);
 struct ETCP_DGRAM* etcp_request_pkt(struct ETCP_CONN* etcp);
 
 static void clear_queue(struct ll_queue* q) {
@@ -217,6 +218,7 @@ struct ETCP_CONN* etcp_connection_create(struct UTUN_INSTANCE* instance, char* n
     etcp->links_up=0;
     etcp->reset_done=0;
     etcp->callbacks_running=0;
+    etcp->ref_count=0;
     etcp->last_rr_link=NULL;
     etcp->name = u_strdup(name);
     // Initialize log_name with local node_id (peer will be updated later when known)
@@ -256,7 +258,19 @@ struct ETCP_CONN* etcp_connection_create(struct UTUN_INSTANCE* instance, char* n
 
     etcp->link_ready_for_send_fn = etcp_link_ready_callback;
 
-    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "[%s] connection initialized. ETCP=%p mtu=%d, next_tx_id=%u",
+    // Add to instance's connections queue (peer_node_id=0 for pending, reindexed later)
+    {
+        struct ll_entry* qe = queue_entry_new(sizeof(struct conn_queue_entry));
+        if (!qe) { etcp_connection_close(etcp); return NULL; }
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)qe->data;
+        ce->peer_node_id = 0;
+        ce->conn = etcp;
+        etcp->conn_queue_entry = qe;
+        etcp->conn_queue = instance->connections;
+        queue_data_put_with_index(instance->connections, qe);
+    }
+
+    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "[%s] connection initialized. ETCP=%p mtu=%d, next_tx_id=%u state=pending",
                 etcp->log_name, etcp, etcp->mtu, etcp->next_tx_id);
 
     // Вызываем callback для нового соединения если установлен
@@ -286,57 +300,15 @@ static void etcp_on_down(struct ETCP_CONN* etcp) {
 }
 
 
-// Close connection with NULL pointer safety (prevents double free)
-void etcp_connection_close(struct ETCP_CONN* etcp) {
-    DEBUG_TRACE(DEBUG_CATEGORY_ETCP, "");
+// Phase 2 resources cleanup (callable both sync and async via call_soon)
+static void etcp_connection_free_resources(struct ETCP_CONN* etcp) {
     if (!etcp) return;
+    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "[%s] freeing resources phase 2", etcp->log_name);
 
-    if (etcp->callbacks_running) {
-        DEBUG_ERROR(DEBUG_CATEGORY_DEBUG, "[%s] FATAL: etcp_connection_close called from inside callback chain — SEGFAULTING to show backtrace",
-                    etcp->log_name);
-        *(volatile int*)0 = 0;
-    }
-
-    if (etcp->links_up!=0) {
-        etcp->links_up=0;
-        etcp_on_down(etcp);
-        }
-
-    // Cancel active timers to prevent memory leaks
-    if (etcp->retrans_timer) {
-        uasync_cancel_timeout(etcp->instance->ua, etcp->retrans_timer);
-        etcp->retrans_timer = NULL;
-    }
-    if (etcp->ack_resp_timer) {
-        uasync_cancel_timeout(etcp->instance->ua, etcp->ack_resp_timer);
-        etcp->ack_resp_timer = NULL;
-    }
-    etcp_metrics_stop_timer(etcp);
-
-    routing_del_conn(etcp);
-    
-    // NOTE: topo_bgp_remove_conn is already called via down_cbk in etcp_on_down() above
-    // DO NOT call it again here to avoid double-processing and ref_count corruption
-    
-    // Очистить транзитные очереди (до pn_deinit/stcp_link_close — waiter'ы на normalizer->input/tx_queue)
-    etcp_router_transit_queues_destroy(etcp);
-    
-    // Deinitialize packet normalizer (this will call routing_del_conn)
-    if (etcp->normalizer) {
-        pn_deinit((struct PKTNORM*)etcp->normalizer);
-        etcp->normalizer = NULL;
-    }
-    
-    // Clear links BEFORE draining queues: etcp_link_close calls
-    // etcp_conn_on_inflight_lim_changed -> input_queue_try_resume
-    // which accesses input_send_q, input_queue, input_wait_ack.
+    // Close links
     if (etcp->links) {
         struct ETCP_LINK* link = etcp->links;
-        while (link) {
-            struct ETCP_LINK* next = link->next;
-            etcp_link_close(link);
-            link = next;
-        }
+        while (link) { struct ETCP_LINK* next = link->next; etcp_link_close(link); link = next; }
         etcp->links = NULL;
     }
 
@@ -350,35 +322,86 @@ void etcp_connection_close(struct ETCP_CONN* etcp) {
 
     // Free callback chains
     { struct etcp_cbk_entry* cbe = etcp->ready_cbks; while (cbe) { struct etcp_cbk_entry* n = cbe->next; u_free(cbe); cbe = n; } etcp->ready_cbks = NULL; }
-    { struct etcp_cbk_entry* cbe = etcp->up_cbks; while (cbe) { struct etcp_cbk_entry* n = cbe->next; u_free(cbe); cbe = n; } etcp->up_cbks = NULL; }
-    { struct etcp_cbk_entry* cbe = etcp->down_cbks; while (cbe) { struct etcp_cbk_entry* n = cbe->next; u_free(cbe); cbe = n; } etcp->down_cbks = NULL; }
+    { struct etcp_cbk_entry* cbe = etcp->up_cbks;    while (cbe) { struct etcp_cbk_entry* n = cbe->next; u_free(cbe); cbe = n; } etcp->up_cbks = NULL; }
+    { struct etcp_cbk_entry* cbe = etcp->down_cbks;  while (cbe) { struct etcp_cbk_entry* n = cbe->next; u_free(cbe); cbe = n; } etcp->down_cbks = NULL; }
 
-    // Free memory pools after all elements are returned
-    if (etcp->inflight_pool) {
-        memory_pool_destroy(etcp->inflight_pool);
-        etcp->inflight_pool = NULL;
-    }
+    if (etcp->inflight_pool) { memory_pool_destroy(etcp->inflight_pool); etcp->inflight_pool = NULL; }
+    if (etcp->io_pool)       { memory_pool_destroy(etcp->io_pool); etcp->io_pool = NULL; }
+
+    u_free(etcp->name);
+    u_free(etcp);
+}
+
+static void etcp_connection_free_deferred(void* arg) {
+    etcp_connection_free_resources((struct ETCP_CONN*)arg);
+}
+
+// Close connection: phase 1 detach + deferred phase 2 cleanup
+void etcp_connection_close(struct ETCP_CONN* etcp) {
+    DEBUG_TRACE(DEBUG_CATEGORY_ETCP, "");
+    if (!etcp) return;
+    if (etcp->state == 2) { DEBUG_WARN(DEBUG_CATEGORY_ETCP, "[%s] already deleted", etcp->log_name); return; }
 
-    if (etcp->io_pool) {
-        memory_pool_destroy(etcp->io_pool);
-        etcp->io_pool = NULL;
+    if (etcp->callbacks_running) {
+        DEBUG_ERROR(DEBUG_CATEGORY_DEBUG, "[%s] FATAL: etcp_connection_close called from inside callback chain — SEGFAULTING to show backtrace",
+                    etcp->log_name);
+        *(volatile int*)0 = 0;
     }
 
-    u_free(etcp->name);
+    // === PHASE 1: detach from external world ===
 
-    {   struct UTUN_INSTANCE* inst = etcp->instance;
-        if (inst && inst->connections) {
-            struct ETCP_CONN** pp = &inst->connections;
-            while (*pp && *pp != etcp) pp = &(*pp)->next;
-            if (*pp) { *pp = etcp->next; if (inst->connections_count) inst->connections_count--; }
-        }
+    if (etcp->links_up != 0) { etcp->links_up = 0; etcp_on_down(etcp); }
+
+    // Cancel active timers
+    if (etcp->retrans_timer) { uasync_cancel_timeout(etcp->instance->ua, etcp->retrans_timer); etcp->retrans_timer = NULL; }
+    if (etcp->ack_resp_timer) { uasync_cancel_timeout(etcp->instance->ua, etcp->ack_resp_timer); etcp->ack_resp_timer = NULL; }
+    etcp_metrics_stop_timer(etcp);
+
+    routing_del_conn(etcp);
+    etcp_router_transit_queues_destroy(etcp);
+
+    if (etcp->normalizer) { pn_deinit((struct PKTNORM*)etcp->normalizer); etcp->normalizer = NULL; }
+
+    // Close links (detach from socket scan queues)
+    if (etcp->links) {
+        struct ETCP_LINK* link = etcp->links;
+        while (link) { struct ETCP_LINK* next = link->next; etcp_link_close(link); link = next; }
+        etcp->links = NULL;
     }
 
-    // Clear next pointer to prevent dangling references
-    etcp->next = NULL;
+    // Remove from instance queue
+    if (etcp->conn_queue && etcp->conn_queue_entry) {
+        queue_remove_data(etcp->conn_queue, etcp->conn_queue_entry);
+        queue_entry_free(etcp->conn_queue_entry);
+        etcp->conn_queue_entry = NULL;
+        etcp->conn_queue = NULL;
+    }
 
-    // TODO: Free rx_list, etc.
-    u_free(etcp);
+    etcp->state = 2; // deleted
+
+    // === PHASE 2: deferred resource cleanup (only if no outstanding refs) ===
+    if (etcp->ref_count == 0)
+        uasync_call_soon(etcp->instance->ua, etcp, etcp_connection_free_deferred);
+    // else: cleanup deferred until last etcp_conn_ref_free()
+}
+
+// Take a reference on connection. Returns -1 if already deleted (state==2).
+int etcp_conn_ref_take(struct ETCP_CONN* conn) {
+    if (!conn) return -1;
+    if (conn->state == 2) { DEBUG_WARN(DEBUG_CATEGORY_ETCP, "[%s] ref_take on deleted conn", conn->log_name); return -1; }
+    conn->ref_count++;
+    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "[%s] ref_take ref_count=%d", conn->log_name, conn->ref_count);
+    return 0;
+}
+
+// Release a reference. If last ref and conn is deleted, schedule deferred free.
+void etcp_conn_ref_free(struct ETCP_CONN* conn) {
+    if (!conn) return;
+    if (conn->ref_count <= 0) { DEBUG_WARN(DEBUG_CATEGORY_ETCP, "[%s] ref_free underflow ref_count=%d", conn->log_name, conn->ref_count); return; }
+    conn->ref_count--;
+    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "[%s] ref_free ref_count=%d state=%d", conn->log_name, conn->ref_count, conn->state);
+    if (conn->ref_count == 0 && conn->state == 2)
+        uasync_call_soon(conn->instance->ua, conn, etcp_connection_free_deferred);
 }
 
 // Reset connection
@@ -543,24 +566,77 @@ void etcp_conn_reinit(struct ETCP_CONN* etcp) {// Если сбой в обме
 // внутренняя функция. Вызывается один раз когда первый линк готов.
 void etcp_conn_ready(struct ETCP_CONN* conn) {
     if (!conn) return;
+    if (conn->initialized) return; // already ready
 
     conn->initialized = 1;
     conn->reset_done = 1;
-    // Если tx_state не установлен (первое подключение без reinit), установим его
-    if (conn->tx_state == 0) {
-        conn->tx_state = ETCP_TX_STATE_DATA_WAIT;
-    }
+    if (conn->tx_state == 0) { conn->tx_state = ETCP_TX_STATE_DATA_WAIT; }
     DEBUG_INFO(DEBUG_CATEGORY_ETCP, "[%s] Connection ready", conn->log_name);
 
+    etcp_conn_queue_set_ready(conn);
+}
+
+// Move from pending to indexed connections, fire ready callbacks
+void etcp_conn_queue_set_ready(struct ETCP_CONN* conn) {
+    if (!conn || conn->state != 0) return;
+
+    // Reindex: remove old entry (key=0), add new entry with real peer_node_id
+    if (conn->conn_queue && conn->conn_queue_entry) {
+        queue_remove_data(conn->conn_queue, conn->conn_queue_entry);
+        queue_entry_free(conn->conn_queue_entry);
+    }
+
+    struct ll_entry* qe = queue_entry_new(sizeof(struct conn_queue_entry));
+    if (!qe) { DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "[%s] failed to alloc queue entry for ready", conn->log_name); return; }
+    struct conn_queue_entry* ce = (struct conn_queue_entry*)qe->data;
+    ce->peer_node_id = conn->peer_node_id;
+    ce->conn = conn;
+    conn->conn_queue_entry = qe;
+    conn->conn_queue = conn->instance->connections;
+    conn->state = 1;
+    queue_data_put_with_index(conn->instance->connections, qe);
+
+    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "[%s] moved to ready queue, state=%d peer_node_id=0x%llx",
+               conn->log_name, conn->state, (unsigned long long)conn->peer_node_id);
+
     etcp_metrics_start_timer(conn);
 
-    // Вызываем callback если установлен
     conn->callbacks_running = 1;
     { struct etcp_cbk_entry* cbe = conn->ready_cbks; while (cbe) { struct etcp_cbk_entry* n = cbe->next; cbe->fn(conn, cbe->arg); cbe = n; } }
     if (conn->links_up) etcp_on_up(conn);
     conn->callbacks_running = 0;
 }
 
+// Set peer_node_id, reindex if already in connections queue
+void etcp_conn_set_peer_node_id(struct ETCP_CONN* conn, uint64_t peer_node_id) {
+    if (!conn) return;
+    if (conn->state == 2) { DEBUG_WARN(DEBUG_CATEGORY_ETCP, "[%s] set_peer_node_id on deleted conn", conn->log_name); return; }
+
+    if (conn->peer_node_id == peer_node_id) return;
+
+    if (conn->state == 1 && conn->peer_node_id != 0) {
+        // Already in indexed queue with old ID — reindex
+        DEBUG_WARN(DEBUG_CATEGORY_ETCP, "[%s] peer_node_id changed 0x%llx -> 0x%llx, reindexing",
+                   conn->log_name, (unsigned long long)conn->peer_node_id, (unsigned long long)peer_node_id);
+        if (conn->conn_queue && conn->conn_queue_entry) {
+            queue_remove_data(conn->conn_queue, conn->conn_queue_entry);
+            queue_entry_free(conn->conn_queue_entry);
+        }
+        struct ll_entry* qe = queue_entry_new(sizeof(struct conn_queue_entry));
+        if (!qe) { DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "[%s] reindex alloc failed", conn->log_name); return; }
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)qe->data;
+        ce->peer_node_id = peer_node_id;
+        ce->conn = conn;
+        conn->conn_queue_entry = qe;
+        conn->conn_queue = conn->instance->connections;
+        queue_data_put_with_index(conn->instance->connections, qe);
+    }
+
+    conn->peer_node_id = peer_node_id;
+    etcp_update_log_name(conn);
+    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "[%s] peer_node_id set to 0x%llx", conn->log_name, (unsigned long long)peer_node_id);
+}
+
 
 // Update log_name when peer_node_id becomes known
 void etcp_update_log_name(struct ETCP_CONN* etcp) {
diff --git a/src/etcp.h b/src/etcp.h
index 0b3b7faa..640a13eb 100644
--- a/src/etcp.h
+++ b/src/etcp.h
@@ -138,11 +138,19 @@ struct ACK_PACKET {
 
 // ETCP connection structure (refactored)
 struct ETCP_CONN {
-    struct ETCP_CONN* next;
+    // State: 0=not ready, 1=ready (indexed in instance->connections), 2=deleted
+    int state; // 0=pending, 1=ready, 2=deleted (phase 1 of close done)
+    int ref_count; // External reference count. >0 blocks deferred resource free.
+                    // Take/free via etcp_conn_ref_take()/etcp_conn_ref_free().
+
     int mtu;
 
     struct UTUN_INSTANCE* instance;
 
+    // Queue entries in instance->connections or instance->pending_connections
+    struct ll_entry* conn_queue_entry; // entry в очереди instance
+    struct ll_queue*  conn_queue;      // указатель на очередь где лежим (pending или connections)
+
     // Links (channels) - linked list
     struct ETCP_LINK* links;
     struct ETCP_LINK* last_rr_link; // последний линк, выбранный round-robin
@@ -252,6 +260,29 @@ struct ETCP_CONN {
 // Functions
 struct ETCP_CONN* etcp_connection_create(struct UTUN_INSTANCE* instance, char* name);
 void etcp_connection_close(struct ETCP_CONN* etcp);
+void etcp_conn_set_peer_node_id(struct ETCP_CONN* conn, uint64_t peer_node_id);
+void etcp_conn_queue_set_ready(struct ETCP_CONN* conn); // move pending->connections, fire ready cbks
+
+/**
+ * @brief Take a reference on the connection (blocks deferred resource free).
+ * @param conn connection
+ * @return 0 on success, -1 if conn is NULL or already in state 2 (deleted).
+ *
+ * Increments ref_count. While ref_count > 0, etcp_connection_close()
+ * will detach but defer resource cleanup until all references are released.
+ * Always pair with etcp_conn_ref_free().
+ */
+int  etcp_conn_ref_take(struct ETCP_CONN* conn);
+
+/**
+ * @brief Release a reference. Triggers deferred resource free if last ref and state==2.
+ * @param conn connection
+ *
+ * Decrements ref_count. If ref_count reaches 0 and the connection has been closed
+ * (state == 2), schedules deferred resource cleanup via uasync_call_soon.
+ * Safe to call on NULL.
+ */
+void etcp_conn_ref_free(struct ETCP_CONN* conn);
 
 void etcp_conn_reset(struct ETCP_CONN* etcp);
 void etcp_links_reset(struct ETCP_CONN* etcp);
diff --git a/src/etcp_connect.c b/src/etcp_connect.c
index f18d4281..3f909126 100644
--- a/src/etcp_connect.c
+++ b/src/etcp_connect.c
@@ -210,22 +210,26 @@ int etcp_connect(struct UTUN_INSTANCE* inst, struct TOPO_NODEQ* node,
     if (!inst || !node || !cb) return -1;
     uint64_t node_id = node->node->node_id;
 
-    struct ETCP_CONN* existing = inst->connections;
-    while (existing) {
-        if (existing->peer_node_id == node_id) {
-            struct ETCP_LINK* l = existing->links;
-            while (l) { if (l->link_state == 3) break; l = l->next; }
-            if (l) {
-                DEBUG_INFO(DEBUG_CATEGORY_ETCP_CONNECT, "[etcp_connect] node 0x%016llx already connected, delivering immediately",
-                           (unsigned long long)node_id);
-                if (flags & ETCP_CONNECT_EARLY) cb(arg, existing, ETCP_CONNECT_EARLY);
-                if (flags & ETCP_CONNECT_LATE)  cb(arg, existing, ETCP_CONNECT_LATE);
-                if ((flags & ETCP_CONNECT_BGP_READY) && existing->routing_exchange_active >= 3)
-                    cb(arg, existing, ETCP_CONNECT_BGP_READY);
-                return 0;
+    // Check if already connected via indexed queue
+    {
+        struct ll_entry* e = queue_find_data_by_index(inst->connections, (const uint8_t*)&node_id);
+        if (e) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            struct ETCP_CONN* existing = ce->conn;
+            if (existing && existing->peer_node_id == node_id) {
+                struct ETCP_LINK* l = existing->links;
+                while (l) { if (l->link_state == 3) break; l = l->next; }
+                if (l) {
+                    DEBUG_INFO(DEBUG_CATEGORY_ETCP_CONNECT, "[etcp_connect] node 0x%016llx already connected, delivering immediately",
+                               (unsigned long long)node_id);
+                    if (flags & ETCP_CONNECT_EARLY) cb(arg, existing, ETCP_CONNECT_EARLY);
+                    if (flags & ETCP_CONNECT_LATE)  cb(arg, existing, ETCP_CONNECT_LATE);
+                    if ((flags & ETCP_CONNECT_BGP_READY) && existing->routing_exchange_active >= 3)
+                        cb(arg, existing, ETCP_CONNECT_BGP_READY);
+                    return 0;
+                }
             }
         }
-        existing = existing->next;
     }
 
     struct ETCP_CONNECT* ctx = connect_find(inst, node_id);
@@ -241,7 +245,6 @@ int etcp_connect(struct UTUN_INSTANCE* inst, struct TOPO_NODEQ* node,
     struct ETCP_CONN* conn = etcp_connection_create(inst, NULL);
     if (!conn) { DEBUG_ERROR(DEBUG_CATEGORY_ETCP_CONNECT, "[etcp_connect] failed to create ETCP_CONN for node 0x%016llx",
                               (unsigned long long)node_id); cb(arg, NULL, 0); return -1; }
-    conn->next = inst->connections; inst->connections = conn; inst->connections_count++;
     if (sc_init_ctx(&conn->crypto_ctx, &inst->my_keys) != SC_OK) {
         DEBUG_ERROR(DEBUG_CATEGORY_ETCP_CONNECT, "[etcp_connect] sc_init_ctx failed for node 0x%016llx", (unsigned long long)node_id);
         etcp_connection_close(conn); cb(arg, NULL, 0); return -1;
diff --git a/src/etcp_connections.c b/src/etcp_connections.c
index 22d862f9..dd977e97 100644
--- a/src/etcp_connections.c
+++ b/src/etcp_connections.c
@@ -32,18 +32,17 @@
 // TCP server: on new incoming connection → create minimal ETCP_CONN
 static void tcp_server_on_link(struct stcp_link *link, void *arg) {
     struct UTUN_INSTANCE *inst = (struct UTUN_INSTANCE *)arg;
-    struct ETCP_CONN *conn = u_calloc(1, sizeof(struct ETCP_CONN));
+    struct ETCP_CONN *conn = etcp_connection_create(inst, NULL);
     if (!conn) return;
-    conn->instance = inst;
     conn->transport_link = link;
     snprintf(conn->log_name, sizeof(conn->log_name), "tcp-[%p]", (void*)link);
-    conn->next = inst->connections;
-    inst->connections = conn;
-    inst->connections_count++;
     struct etcp_cbk_entry* cbe = inst->new_conn_cbks;
     while (cbe) { struct etcp_cbk_entry* n = cbe->next; cbe->fn(conn, cbe->arg); cbe = n; }
     { struct etcp_cbk_entry* rcb = conn->ready_cbks; while (rcb) { struct etcp_cbk_entry* n = rcb->next; rcb->fn(conn, rcb->arg); rcb = n; } }
-    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "TCP server new conn=%p total=%d", (void*)conn, inst->connections_count);
+    DEBUG_INFO(DEBUG_CATEGORY_ETCP, "TCP server new conn=%p total=%d pending=%d",
+               (void*)conn,
+               queue_entry_count(inst->connections),
+               queue_entry_count(inst->connections));
 }
 
 // Forward declaration
@@ -1464,8 +1463,7 @@ static int handle_init_response_client(struct ETCP_SOCKET* e_sock, struct ETCP_D
 
 //        DEBUG_INFO(DEBUG_CATEGORY_CONNECTION, "Received INIT_RESPONSE from server_node_id=%llu, mtu=%d", (unsigned long long)server_node_id, link->mtu);
 
-    link->etcp->peer_node_id = server_node_id; // If not set
-    etcp_update_log_name(link->etcp);  // Update log_name with peer_node_id
+    etcp_conn_set_peer_node_id(link->etcp, server_node_id);
 
     link->initialized = 1;// получен init response (client)
     link->link_state = 3; // connected
@@ -1678,11 +1676,11 @@ void etcp_connections_read_callback_socket(socket_t sock, void* arg) {
                req->src_ipv4[0], req->src_ipv4[1], req->src_ipv4[2], req->src_ipv4[3],
                src_port, session_id, sockaddr_storage_to_str(&addr).str);
 
-    struct ETCP_CONN* conn=e_sock->instance->connections;
-    while (conn) {// ищем есть ли подключение к этому пиру
-        if (conn->peer_node_id==peer_id) break;
-        conn=conn->next;
-        }
+    struct ETCP_CONN* conn = NULL;
+    {
+        struct ll_entry* e = queue_find_data_by_index(e_sock->instance->connections, (const uint8_t*)&peer_id);
+        if (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data; conn = ce->conn; }
+    }
 
     int new_conn=0;
     if (!conn || conn->peer_node_id!=peer_id) {// создаём новое подключение [new etcp]
@@ -1690,14 +1688,11 @@ void etcp_connections_read_callback_socket(socket_t sock, void* arg) {
         conn=etcp_connection_create(e_sock->instance,"");
         if (!conn) { errorcode=55; DEBUG_ERROR(DEBUG_CATEGORY_CONNECTION, "failed to create connection"); goto ec_fr; }
         memcpy(&conn->crypto_ctx, &sc, sizeof(sc));
-        conn->peer_node_id=peer_id;
-        etcp_update_log_name(conn);
+        etcp_conn_set_peer_node_id(conn, peer_id);
         DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "New connection received on socket %s: log_name=%s peer_id=%lu peer:%s", e_sock->name, conn->log_name, (unsigned long)peer_id, sockaddr_storage_to_str(&addr).str);
-        DEBUG_DEBUG(DEBUG_CATEGORY_CONNECTION, "New connection from %s peer_id=%ld etcp=%p", ip_to_str(&addr, addr.ss_family).str, peer_id, conn);
-        conn->next = e_sock->instance->connections;
-        e_sock->instance->connections = conn;
-        e_sock->instance->connections_count++;
-        DEBUG_INFO(DEBUG_CATEGORY_CONNECTION, "Added incoming connection %p to instance, total count: %d", conn, e_sock->instance->connections_count);
+        DEBUG_DEBUG(DEBUG_CATEGORY_CONNECTION, "New connection from %s peer_id=%ld etcp=%p total=%d",
+                     ip_to_str(&addr, addr.ss_family).str, peer_id, conn,
+                     queue_entry_count(e_sock->instance->connections));
         }
     else {// check keys если существующее подключение
         if (memcmp(conn->crypto_ctx.peer_public_key, sc.peer_public_key, SC_PUBKEY_SIZE)) { errorcode=5; DEBUG_ERROR(DEBUG_CATEGORY_CRYPTO, "peer key mismatch for node %016llx", (unsigned long long)peer_id); goto ec_fr; }// коллизия - peer id совпал а ключи разные.
@@ -2065,8 +2060,8 @@ int init_connections(struct UTUN_INSTANCE* instance) {
 
     // Initialize clients - create outgoing connections
     struct CFG_CLIENT* client = config->clients;
-    DEBUG_DEBUG(DEBUG_CATEGORY_CONNECTION, "init_connections called, instance=%p, config=%p, clients=%p, connections_count=%d", 
-                instance, config, config ? config->clients : NULL, instance ? instance->connections_count : -1);
+    DEBUG_DEBUG(DEBUG_CATEGORY_CONNECTION, "init_connections called, instance=%p, config=%p, clients=%p, total_conns=%d", 
+                instance, config, config ? config->clients : NULL, instance ? queue_entry_count(instance->connections) : -1);
     while (client) {
         // Check if client has required configuration
         DEBUG_INFO(DEBUG_CATEGORY_CONNECTION, "Client %s - keepalive=%d, links=%p, peer_key_len=%zu", 
@@ -2196,22 +2191,18 @@ int init_connections(struct UTUN_INSTANCE* instance) {
             client_link = client_link->next;
         }
 
-        etcp_conn->next = instance->connections;
-        instance->connections = etcp_conn;
-        instance->connections_count++;
-        
-        DEBUG_INFO(DEBUG_CATEGORY_CONNECTION, "Added connection %p to instance, total count: %d", etcp_conn, instance->connections_count);
         client = client->next;
     }
     
     // If there are clients configured but no connections created, that's an error
     // If there are no clients (server-only mode), 0 connections is OK (server will accept incoming)
-    if (instance->connections_count == 0 && config->clients != NULL) {
+    int total_conns = queue_entry_count(instance->connections);
+    if (total_conns == 0 && config->clients != NULL) {
         DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "Clients configured but no connections initialized");
         return -1;
     }
     
-    DEBUG_INFO(DEBUG_CATEGORY_CONNECTION, "Initialized %d connections", instance->connections_count);
+    DEBUG_INFO(DEBUG_CATEGORY_CONNECTION, "Initialized %d connections", total_conns);
     // Return 1 if there was a partial socket initialization error
     if (socket_result == 1) return 1;
     return 0;
diff --git a/src/etcp_dump.c b/src/etcp_dump.c
index 9cb372a6..d3f1249d 100644
--- a/src/etcp_dump.c
+++ b/src/etcp_dump.c
@@ -233,13 +233,16 @@ void etcp_dump_all_conns(struct UTUN_INSTANCE* instance) {
     }
     DUMP_HDR("=== DUMP ALL CONNS for instance node=0x%llx ===",
                (unsigned long long)instance->node_id);
-    struct ETCP_CONN* conn = instance->connections;
+    struct ll_entry* entry = instance->connections->head;
     int idx = 0;
-    while (conn) {
-        DUMP_HDR("--- CONN %d ---", idx);
-        etcp_dump_conn_state(conn);
-        conn = conn->next;
-        idx++;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        if (ce && ce->conn) {
+            DUMP_HDR("--- CONN %d ---", idx);
+            etcp_dump_conn_state(ce->conn);
+            idx++;
+        }
+        entry = entry->next;
     }
     if (idx == 0) DUMP_HDR("--- NO CONNECTIONS ---");
     DUMP_HDR("=== END DUMP ALL ===");
diff --git a/src/ntp_node_time.c b/src/ntp_node_time.c
index d1945cdc..2080f2f0 100644
--- a/src/ntp_node_time.c
+++ b/src/ntp_node_time.c
@@ -152,9 +152,10 @@ void ntp_node_sync_peers(struct UTUN_INSTANCE* inst) {
     if (!inst || !ntp_time_is_synced(inst)) return;
 
     int sent = 0;
-    for (struct ETCP_CONN* conn = inst->connections; conn; conn = conn->next) {
-        if (!conn->initialized || !conn->links_up) continue;
-        if (send_time_sync(inst, conn->peer_node_id) == 0) sent++;
+    for (struct ll_entry* entry = inst->connections->head; entry; entry = entry->next) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        if (!ce->conn->initialized || !ce->conn->links_up) continue;
+        if (send_time_sync(inst, ce->conn->peer_node_id) == 0) sent++;
     }
 
     DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "NTP_node: broadcast TIME_SYNC to %d peers", sent);
diff --git a/src/topo_group.c b/src/topo_group.c
index fa788172..737a9cab 100644
--- a/src/topo_group.c
+++ b/src/topo_group.c
@@ -366,8 +366,8 @@ void topo_group_new_conn(struct TOPO_GROUP* group, struct ETCP_CONN* conn) {
     topo_group_add_to_senders(group, conn);
     if (peer_nq && peer_nq->alien) { DEBUG_INFO(DEBUG_CATEGORY_BGP, "peer 0x%016llx is alien, skipping route exchange", (unsigned long long)conn->peer_node_id); return; }
 
-    struct ETCP_CONN* c = conn->instance->connections;
-    while (c) { struct ETCP_LINK* l = c->links; while (l) { if (l->initialized && l->conn && l->nat_check_status < NAT_CHECK_IN_PROGRESS) topo_group_start_link_nat_check(group, l); l = l->next; } c = c->next; }
+    struct ll_entry* entry = conn->instance->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data; struct ETCP_LINK* l = ce->conn->links; while (l) { if (l->initialized && l->conn && l->nat_check_status < NAT_CHECK_IN_PROGRESS) topo_group_start_link_nat_check(group, l); l = l->next; } entry = entry->next; }
 
     topo_group_send_table_request(group, conn);
 }
@@ -839,7 +839,7 @@ void topo_group_send_nat_check_req(struct ETCP_CONN* conn, uint8_t socket_id) {
 void topo_group_request_nat_check_all(struct TOPO_GROUP* group) {
     if (!group || !group->instance) return;
     int count = 0;
-    struct ETCP_CONN* conn = group->instance->connections; while (conn) { struct ETCP_LINK* link = conn->links; while (link) { if (link->nat_check_status < NAT_CHECK_IN_PROGRESS) topo_group_start_link_nat_check(group, link); count++; link = link->next; } conn = conn->next; }
+    struct ll_entry* entry = group->instance->connections->head; while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data; struct ETCP_LINK* link = ce->conn->links; while (link) { if (link->nat_check_status < NAT_CHECK_IN_PROGRESS) topo_group_start_link_nat_check(group, link); count++; link = link->next; } entry = entry->next; }
 }
 
 void topo_group_send_withdraw(struct TOPO_GROUP* group, uint64_t node_id) {
diff --git a/src/utun_instance.c b/src/utun_instance.c
index f41417de..54025db6 100644
--- a/src/utun_instance.c
+++ b/src/utun_instance.c
@@ -106,6 +106,9 @@ static int instance_init_common(struct UTUN_INSTANCE* instance, struct UASYNC* u
         DEBUG_ERROR(DEBUG_CATEGORY_CONFIG, "Failed to create networks queue");
         return -1;
     }
+    // Initialize connection queue
+    instance->connections = queue_new(ua, 256, 0, 8, "connections");
+    if (!instance->connections) { DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "Failed to create connections queue"); return -1; }
     struct CFG_NETWORK *net = config->networks;
     while (net) {
         struct ll_entry *entry = queue_entry_new(sizeof(struct NETWORK_ENTRY));
@@ -397,17 +400,17 @@ void utun_instance_destroy(struct UTUN_INSTANCE *instance) {
     instance->etcp_sockets = NULL;
     DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[INSTANCE_DESTROY] ETCP sockets cleanup complete");
     
-    // Safe cleanup of ETCP connections with NULL pointer checks
-    struct ETCP_CONN* conn = instance->connections;
-    while (conn) {
-        struct ETCP_CONN* next = conn->next;
-        DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[INSTANCE_DESTROY] Closing connection %p", conn);
-        if (conn) {  // Дополнительная проверка на случай поврежденного списка
-            etcp_connection_close(conn);  // Закрыть соединение (с проверкой NULL внутри)
+    // Cleanup ETCP connections (phase 1 detach + deferred phase 2 via call_soon)
+    {
+        struct ll_entry* entry = instance->connections->head;
+        while (entry) {
+            struct ll_entry* next = entry->next;
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            if (ce && ce->conn) etcp_connection_close(ce->conn);
+            entry = next;
         }
-        conn = next;
     }
-    instance->connections = NULL;
+    queue_free(instance->connections); instance->connections = NULL;
     DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[INSTANCE_DESTROY] ETCP connections cleanup complete");
     
     struct PING_CONTEXT* p = instance->pending_pings;
@@ -578,7 +581,7 @@ int utun_instance_init(struct UTUN_INSTANCE *instance) {
         return -1;
     }
     
-    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Connections initialized successfully, count=%d", instance->connections_count);
+    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Connections initialized successfully, count=%d", queue_entry_count(instance->connections));
     
     // Initialize control server if configured
     if (instance->config->global.control_sock.ss_family != 0) {
@@ -654,16 +657,15 @@ void utun_instance_diagnose_leaks(struct UTUN_INSTANCE *instance, const char *ph
     }
     
     // Подсчёт ETCP соединений
-    struct ETCP_CONN *conn = instance->connections;
-    while (conn) {
-        report.etcp_connections_count++;
-        // Подсчёт линков в соединениях
-        struct ETCP_LINK *link = conn->links;
-        while (link) {
-            report.etcp_links_count++;
-            link = link->next;
+    {
+        struct ll_entry* entry = instance->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            report.etcp_connections_count++;
+            struct ETCP_LINK *link = ce->conn->links;
+            while (link) { report.etcp_links_count++; link = link->next; }
+            entry = entry->next;
         }
-        conn = conn->next;
     }
     
     DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "[LEAK DIAGNOSIS] Phase: %s", phase);
@@ -788,9 +790,12 @@ struct UTUN_INSTANCE *utun_instance_reload(struct UTUN_INSTANCE *instance, struc
     // Clients [client:] and links (link=)
     for (struct CFG_CLIENT *nc = new_config->clients; nc; nc = nc->next) {
         struct ETCP_CONN *conn = NULL;
-        for (struct ETCP_CONN *c = instance->connections; c; c = c->next) {
-            if (strcmp(nc->name, c->name) == 0) {
-                conn = c; break;
+        {
+            struct ll_entry* entry = instance->connections->head;
+            while (entry) {
+                struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+                if (strcmp(nc->name, ce->conn->name) == 0) { conn = ce->conn; break; }
+                entry = entry->next;
             }
         }
         if (!conn) {
diff --git a/src/utun_instance.h b/src/utun_instance.h
index 1e705669..f59dd506 100644
--- a/src/utun_instance.h
+++ b/src/utun_instance.h
@@ -52,6 +52,12 @@ struct NETWORK_ENTRY {
     char name[64];
 };
 
+// Queue entry for instance->connections (indexed by peer_node_id)
+struct conn_queue_entry {
+    uint64_t peer_node_id;
+    struct ETCP_CONN* conn;
+};
+
 // uTun instance configuration
 struct UTUN_INSTANCE {
     // Identification
@@ -87,9 +93,8 @@ struct UTUN_INSTANCE {
     // State
     int running;
 
-    // Connections (список всех подключений для instance)
-    struct ETCP_CONN* connections;// linked-list
-    int connections_count;  // Number of connections
+    // Connections (очередь всех подключений для instance)
+    struct ll_queue* connections;        // indexed by peer_node_id (0=pending), data=conn_queue_entry
     
     // Callback chain for new ETCP connections
     struct etcp_cbk_entry* new_conn_cbks;
@@ -135,7 +140,6 @@ struct UTUN_INSTANCE {
     // etcp_router bindings и seq-connections (per-instance service routing)
     struct ETCP_ROUTER_BINDINGS router_bindings;
     struct ll_queue* router_conns;
-    struct ll_queue* chat_connections; // chat P2P connections indexed by node_id
     struct CONN_MGR* conn_mgr;       // Connection Manager (может быть NULL)
     struct DB_SYNC* db_sync;         // Distributed DB sync (может быть NULL)
 
diff --git a/tests/bbr_integration/test_bbr_integration.c b/tests/bbr_integration/test_bbr_integration.c
index 375db676..f546b107 100644
--- a/tests/bbr_integration/test_bbr_integration.c
+++ b/tests/bbr_integration/test_bbr_integration.c
@@ -187,7 +187,9 @@ static void send_wtr_cb(struct ll_queue* q, void* arg) {
 
 static void send_burst(struct test_ctx* ctx) {
     if (ctx->test_done) return;
-    struct ETCP_CONN* conn = ctx->sender->connections;
+    struct ETCP_CONN* conn = NULL;
+    if (ctx->sender->connections && ctx->sender->connections->head)
+        conn = ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn;
     if (!conn || !conn->initialized) return;
 
     if (conn->normalizer && conn->normalizer->input) {
@@ -241,9 +243,11 @@ static void print_metrics(struct test_ctx* ctx) {
     double        pace_kbps   = 0;
     double        rtt_ms      = 0;
 
-    if (ctx->sender->connections && ctx->sender->connections->links) {
-        struct ETCP_LINK* l = ctx->sender->connections->links;
-        struct ETCP_CONN* c = ctx->sender->connections;
+    struct ETCP_CONN* c = NULL;
+    if (ctx->sender->connections && ctx->sender->connections->head)
+        c = ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn;
+    if (c && c->links) {
+        struct ETCP_LINK* l = c->links;
         lk_status = l->link_status ? " UP" : " DN";
         lk_reinit = c->reinit_count;
         lk_rtrns  = l->total_retransmissions;
@@ -376,11 +380,14 @@ int main(void) {
 
     /* Wait for connection */
     printf("Waiting for connection...\n");
+    struct ETCP_CONN* conn = NULL;
     uint64_t t0 = now_us();
     while ((now_us() - t0) < 10000000ULL) {
         uasync_poll(ctx.ua, 1);
-        if (ctx.sender->connections && ctx.sender->connections->links) {
-            struct ETCP_LINK* l = ctx.sender->connections->links;
+        if (ctx.sender->connections && ctx.sender->connections->head)
+            conn = ((struct conn_queue_entry*)ctx.sender->connections->head->data)->conn;
+        if (conn && conn->links) {
+            struct ETCP_LINK* l = conn->links;
             if (l->initialized && l->link_status == 1) break;
         }
     }
@@ -388,9 +395,9 @@ int main(void) {
     t0 = now_us();
     while ((now_us() - t0) < 500000ULL) uasync_poll(ctx.ua, 1);
 
-    if (ctx.sender->connections && ctx.sender->connections->normalizer && ctx.sender->connections->normalizer->input) {
-        queue_set_threshold(ctx.sender->connections->normalizer->input, 0, 0);
-        queue_set_waiter_defer(ctx.sender->connections->normalizer->input, 1);
+    if (conn && conn->normalizer && conn->normalizer->input) {
+        queue_set_threshold(conn->normalizer->input, 0, 0);
+        queue_set_waiter_defer(conn->normalizer->input, 1);
     }
 
     /* Start test */
@@ -416,10 +423,15 @@ int main(void) {
             const struct dummynet_stats* ds = dummynet_get_stats(ctx.dn, DUMMYNET_FORWARD);
             const char* lks = "?";
             uint32_t rein = 0, rtrns = 0;
-            if (ctx.sender->connections && ctx.sender->connections->links) {
-                lks   = ctx.sender->connections->links->link_status ? "UP" : "DN";
-                rein  = ctx.sender->connections->reinit_count;
-                rtrns = ctx.sender->connections->links->total_retransmissions;
+            {
+                struct ETCP_CONN* c = NULL;
+                if (ctx.sender->connections && ctx.sender->connections->head)
+                    c = ((struct conn_queue_entry*)ctx.sender->connections->head->data)->conn;
+                if (c && c->links) {
+                    lks   = c->links->link_status ? "UP" : "DN";
+                    rein  = c->reinit_count;
+                    rtrns = c->links->total_retransmissions;
+                }
             }
             printf("  t=%lus Lk=%s Rein=%u Rtrns=%u recv=%lu dn_tx=%llu dn_lost=%llu\n",
                    (unsigned long)elapsed, lks, rein, rtrns, (unsigned long)ctx.bytes_received,
@@ -455,31 +467,35 @@ int main(void) {
                (unsigned long long)ds_bk->recv, (unsigned long long)ds_bk->sent,
                (unsigned long long)ds_bk->lost, (unsigned long long)ds_bk->dropped);
 
-    if (ctx.sender->connections) {
-        struct ETCP_CONN* c = ctx.sender->connections;
-        printf("ETCP:               reinit=%u reset=%u links_up=%u\n",
-               c->reinit_count, c->reset_count, c->links_up);
-        if (c->links) {
-            struct ETCP_LINK* l = c->links;
-            int lnum = 0;
-            while (l) {
-                lnum++;
-                printf("  Link%d:             status=%s state=%u rKeep=%u sKeep=%u retrans=%lu"
-                       " inflight=%u/%u lim=%u kB  rtt=%u ms\n",
-                       lnum, l->link_status ? "UP" : "DN", l->link_state,
-                       l->recv_keepalive, l->remote_keepalive,
-                       (unsigned long)l->total_retransmissions,
-                       l->inflight_bytes, l->inflight_packets, l->inflight_lim_bytes / 1024,
-                       l->rtt_last);
-                if (l->bbr)
-                    printf("         BBR:          mode=%d cycle=%d full_bw=%d loss_rnd=%d"
-                           " minrtt=%.1fms bw_hi=%.0fK bw_lo=%.0fK pace=%.0fK infl_hi=%.1fK infl_lo=%.1fK\n",
-                           l->bbr->mode, l->bbr->cycle_idx, l->bbr->full_bw_reached, l->bbr->loss_in_round,
-                           (double)l->bbr->min_rtt_us / 1000.0,
-                            (double)l->bbr->bw_hi[0] / 2097.152, (double)l->bbr->bw_lo / 2097.152,
-                           (double)l->bbr_pacing_rate / 125.0,
-                           (double)l->bbr->inflight_hi / 1024.0, (double)l->bbr->inflight_lo / 1024.0);
-                l = l->next;
+    {
+        struct ETCP_CONN* c = NULL;
+        if (ctx.sender->connections && ctx.sender->connections->head)
+            c = ((struct conn_queue_entry*)ctx.sender->connections->head->data)->conn;
+        if (c) {
+            printf("ETCP:               reinit=%u reset=%u links_up=%u\n",
+                   c->reinit_count, c->reset_count, c->links_up);
+            if (c->links) {
+                struct ETCP_LINK* l = c->links;
+                int lnum = 0;
+                while (l) {
+                    lnum++;
+                    printf("  Link%d:             status=%s state=%u rKeep=%u sKeep=%u retrans=%lu"
+                           " inflight=%u/%u lim=%u kB  rtt=%u ms\n",
+                           lnum, l->link_status ? "UP" : "DN", l->link_state,
+                           l->recv_keepalive, l->remote_keepalive,
+                           (unsigned long)l->total_retransmissions,
+                           l->inflight_bytes, l->inflight_packets, l->inflight_lim_bytes / 1024,
+                           l->rtt_last);
+                    if (l->bbr)
+                        printf("         BBR:          mode=%d cycle=%d full_bw=%d loss_rnd=%d"
+                               " minrtt=%.1fms bw_hi=%.0fK bw_lo=%.0fK pace=%.0fK infl_hi=%.1fK infl_lo=%.1fK\n",
+                               l->bbr->mode, l->bbr->cycle_idx, l->bbr->full_bw_reached, l->bbr->loss_in_round,
+                               (double)l->bbr->min_rtt_us / 1000.0,
+                                (double)l->bbr->bw_hi[0] / 2097.152, (double)l->bbr->bw_lo / 2097.152,
+                               (double)l->bbr_pacing_rate / 125.0,
+                               (double)l->bbr->inflight_hi / 1024.0, (double)l->bbr->inflight_lo / 1024.0);
+                    l = l->next;
+                }
             }
         }
     }
@@ -505,8 +521,13 @@ int main(void) {
     }
 
     /* Cleanup */
-    if (ctx.sender->connections && ctx.sender->connections->normalizer && ctx.sender->connections->normalizer->input)
-        queue_waiter_cancel(ctx.sender->connections->normalizer->input, &ctx.waiter);
+    {
+        struct ETCP_CONN* cc = NULL;
+        if (ctx.sender->connections && ctx.sender->connections->head)
+            cc = ((struct conn_queue_entry*)ctx.sender->connections->head->data)->conn;
+        if (cc && cc->normalizer && cc->normalizer->input)
+            queue_waiter_cancel(cc->normalizer->input, &ctx.waiter);
+    }
     dummynet_destroy(ctx.dn);
     utun_instance_destroy(ctx.sender);
     utun_instance_destroy(ctx.receiver);
diff --git a/tests/test_bgp_route_exchange.c b/tests/test_bgp_route_exchange.c
index 21da299e..0bf4a9db 100644
--- a/tests/test_bgp_route_exchange.c
+++ b/tests/test_bgp_route_exchange.c
@@ -195,17 +195,17 @@ static void cleanup_temp_configs(void) {
 }
 
 static int has_initialized_link(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) { struct ETCP_LINK* l = conn->links; while (l) { if (l->initialized) return 1; l = l->next; } conn = conn->next; }
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data; struct ETCP_LINK* l = ce->conn->links; while (l) { if (l->initialized) return 1; l = l->next; } entry = entry->next; }
     return 0;
 }
 
 static int count_initialized_links(struct UTUN_INSTANCE* inst) {
     int n = 0;
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) { struct ETCP_LINK* l = conn->links; while (l) { if (l->initialized) n++; l = l->next; } conn = conn->next; }
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data; struct ETCP_LINK* l = ce->conn->links; while (l) { if (l->initialized) n++; l = l->next; } entry = entry->next; }
     return n;
 }
 
@@ -221,10 +221,11 @@ static int check_learned_route(struct UTUN_INSTANCE* inst, uint32_t network, uin
 }
 
 static struct ETCP_LINK* find_client_link(struct UTUN_INSTANCE* inst, int idx) {
-    if (!inst) return NULL;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        struct ETCP_LINK* l = conn->links;
+    if (!inst || !inst->connections) return NULL;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_LINK* l = ce->conn->links;
         while (l) {
             if (l->is_server == 0) {
                 if (idx == 0) return l;
@@ -232,7 +233,7 @@ static struct ETCP_LINK* find_client_link(struct UTUN_INSTANCE* inst, int idx) {
             }
             l = l->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return NULL;
 }
diff --git a/tests/test_bgp_triangle.c b/tests/test_bgp_triangle.c
index 5c3ea308..01eceb35 100644
--- a/tests/test_bgp_triangle.c
+++ b/tests/test_bgp_triangle.c
@@ -162,26 +162,28 @@ static int route_count_for_node(struct UTUN_INSTANCE* inst, uint64_t node_id) {
 
 static int count_initialized_links(struct UTUN_INSTANCE* inst) {
     int n = 0;
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        struct ETCP_LINK* l = conn->links;
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_LINK* l = ce->conn->links;
         while (l) { if (l->initialized) n++; l = l->next; }
-        conn = conn->next;
+        entry = entry->next;
     }
     return n;
 }
 
 static struct ETCP_LINK* find_client_link(struct UTUN_INSTANCE* inst, int idx) {
-    if (!inst) return NULL;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        struct ETCP_LINK* l = conn->links;
+    if (!inst || !inst->connections) return NULL;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_LINK* l = ce->conn->links;
         while (l) {
             if (l->is_server == 0) { if (idx == 0) return l; idx--; }
             l = l->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return NULL;
 }
diff --git a/tests/test_conn_mgr.c b/tests/test_conn_mgr.c
index aa77239d..070d87d0 100644
--- a/tests/test_conn_mgr.c
+++ b/tests/test_conn_mgr.c
@@ -56,8 +56,11 @@ static char* gv(const char* p, const char* k) {
     free_config(c); return r;
 }
 static int lks(struct UTUN_INSTANCE* i) {
-    int n = 0; struct ETCP_CONN* c = i->connections;
-    while (c) { struct ETCP_LINK* l = c->links; while (l) { if (l->initialized && l->link_status) n++; l = l->next; } c = c->next; }
+    int n = 0; struct ll_entry* entry = i->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* c = ce->conn;
+        struct ETCP_LINK* l = c->links; while (l) { if (l->initialized && l->link_status) n++; l = l->next; }
+        entry = entry->next; }
     return n;
 }
 static void fail(const char* msg) { fprintf(stderr, "FAIL: %s\n", msg); fflush(stderr); result = 2; }
diff --git a/tests/test_db_sync.c b/tests/test_db_sync.c
index 8f4e447b..e60d3845 100644
--- a/tests/test_db_sync.c
+++ b/tests/test_db_sync.c
@@ -151,8 +151,11 @@ static void sleep_tb(int tb) {
 // ---- Condition functions ----
 static int cond_links_init(void) {
     if (!inst_a || !inst_b) return 0;
-    struct ETCP_CONN* ca = inst_a->connections;
-    while (ca) { struct ETCP_LINK* l = ca->links; while (l) { if (l->initialized) return 1; l = l->next; } ca = ca->next; }
+    struct ll_entry* entry = inst_a->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* ca = ce->conn;
+        struct ETCP_LINK* l = ca->links; while (l) { if (l->initialized) return 1; l = l->next; }
+        entry = entry->next; }
     return 0;
 }
 
diff --git a/tests/test_etcp_100_packets.c b/tests/test_etcp_100_packets.c
index 506bf9cd..d069d688 100644
--- a/tests/test_etcp_100_packets.c
+++ b/tests/test_etcp_100_packets.c
@@ -139,15 +139,17 @@ static void generate_packet_data(int seq, uint8_t* buffer, int size) {
 
 // Check if connection is established
 static int is_connection_established(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         struct ETCP_LINK* link = conn->links;
         while (link) {
             if (link->initialized) return 1;
             link = link->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return 0;
 }
@@ -156,7 +158,7 @@ static int is_connection_established(struct UTUN_INSTANCE* inst) {
 static void send_packets_fwd(void) {
     if (!client_instance || packets_sent_fwd >= TOTAL_PACKETS) return;
     
-    struct ETCP_CONN* conn = client_instance->connections;
+    struct ETCP_CONN* conn = (client_instance->connections && client_instance->connections->head) ? ((struct conn_queue_entry*)client_instance->connections->head->data)->conn : NULL;
     if (!conn || !conn->input_queue) return;
     
     // Start timing on first packet
@@ -193,7 +195,7 @@ static void send_packets_fwd(void) {
 static void send_packets_back(void) {
     if (!server_instance || packets_sent_back >= TOTAL_PACKETS) return;
     
-    struct ETCP_CONN* conn = server_instance->connections;
+    struct ETCP_CONN* conn = (server_instance->connections && server_instance->connections->head) ? ((struct conn_queue_entry*)server_instance->connections->head->data)->conn : NULL;
     if (!conn || !conn->input_queue) return;
     
     // Start timing on first packet
@@ -230,7 +232,7 @@ static void send_packets_back(void) {
 static void check_received_packets_fwd(void) {
     if (!server_instance) return;
     
-    struct ETCP_CONN* conn = server_instance->connections;
+    struct ETCP_CONN* conn = (server_instance->connections && server_instance->connections->head) ? ((struct conn_queue_entry*)server_instance->connections->head->data)->conn : NULL;
     if (!conn || !conn->output_queue) return;
     
     // Disable routing callback to keep packets in output_queue for test verification
@@ -263,7 +265,7 @@ static void check_received_packets_fwd(void) {
 static void check_received_packets_back(void) {
     if (!client_instance) return;
     
-    struct ETCP_CONN* conn = client_instance->connections;
+    struct ETCP_CONN* conn = (client_instance->connections && client_instance->connections->head) ? ((struct conn_queue_entry*)client_instance->connections->head->data)->conn : NULL;
     if (!conn || !conn->output_queue) return;
 
     // Disable routing callback to keep packets in output_queue for test verification
diff --git a/tests/test_etcp_api.c b/tests/test_etcp_api.c
index b74ea4b8..56bfc786 100644
--- a/tests/test_etcp_api.c
+++ b/tests/test_etcp_api.c
@@ -280,8 +280,10 @@ static void client_recv_callback(struct ETCP_CONN* conn, struct ll_entry* entry)
 // Check if connection is established and crypto session key is ready
 static int is_connection_established(struct UTUN_INSTANCE* inst) {
     if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         struct ETCP_LINK* link = conn->links;
         while (link) {
             // Проверяем что линк инициализирован И session_key установлен (не нулевой)
@@ -300,15 +302,17 @@ static int is_connection_established(struct UTUN_INSTANCE* inst) {
             }
             link = link->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return 0;
 }
 
 // Get first connection from instance
 static struct ETCP_CONN* get_first_connection(struct UTUN_INSTANCE* inst) {
-    if (!inst) return NULL;
-    return inst->connections;
+    if (!inst || !inst->connections) return NULL;
+    if (!inst->connections->head) return NULL;
+    struct conn_queue_entry* ce = (struct conn_queue_entry*)inst->connections->head->data;
+    return ce->conn;
 }
 
 // Send packets from client to server (forward direction) via etcp_send
diff --git a/tests/test_etcp_congestion.c b/tests/test_etcp_congestion.c
index 36821fad..eea561b4 100644
--- a/tests/test_etcp_congestion.c
+++ b/tests/test_etcp_congestion.c
@@ -187,8 +187,8 @@ static void send_timer_cb(void* arg) {
 static void send_burst(struct test_ctx* ctx) {
     if (ctx->test_done) return;
     if (!ctx->sender || !ctx->sender->connections) return;
-    struct ETCP_CONN* conn = ctx->sender->connections;
-    if (!conn->initialized) return;
+    struct ETCP_CONN* conn = (ctx->sender->connections && ctx->sender->connections->head) ? ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn : NULL;
+    if (!conn || !conn->initialized) return;
 
     int sent = 0;
     while (sent < 64) {
@@ -232,7 +232,8 @@ static void log_metrics(struct test_ctx* ctx) {
     ctx->last_bytes_recv = ctx->bytes_received;
 
     if (!ctx->sender || !ctx->sender->connections) return;
-    struct ETCP_CONN* sconn = ctx->sender->connections;
+    struct ETCP_CONN* sconn = (ctx->sender->connections && ctx->sender->connections->head) ? ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn : NULL;
+    if (!sconn) return;
     struct ETCP_LINK* link = sconn->links;
     int idx = 0;
     while (link && idx < 2) {
@@ -343,10 +344,11 @@ int main(void) {
     int links_ready = 0;
     while ((now_us() - t0) < 10000000ULL) {
         uasync_poll(ctx.ua, 1);
-        if (ctx.sender->connections && ctx.sender->connections->links) {
-            struct ETCP_LINK* l = ctx.sender->connections->links;
+        { struct ETCP_CONN* c = (ctx.sender->connections && ctx.sender->connections->head) ? ((struct conn_queue_entry*)ctx.sender->connections->head->data)->conn : NULL;
+          if (c && c->links) {
+            struct ETCP_LINK* l = c->links;
             if (l->initialized && l->link_status == 1) { links_ready = 1; break; }
-        }
+          } }
     }
     printf("Links ready, waiting stabilize...\n");
     t0 = now_us();
@@ -383,7 +385,7 @@ int main(void) {
         if (elapsed >= TEST_DURATION_MS) ctx.test_done = 1;
         if (elapsed - last_progress >= 1000) {
             last_progress = elapsed;
-            int l1 = ctx.sender->connections && ctx.sender->connections->links ? 1 : 0;
+            int l1 = (ctx.sender->connections && ctx.sender->connections->head) ? 1 : 0;
             printf("  t=%lus sent=%lu recv=%lu links=%d\n", (unsigned long)elapsed, (unsigned long)ctx.bytes_sent, (unsigned long)ctx.bytes_received, l1);
         }
     }
diff --git a/tests/test_etcp_connect.c b/tests/test_etcp_connect.c
index eb089d88..4b99549d 100644
--- a/tests/test_etcp_connect.c
+++ b/tests/test_etcp_connect.c
@@ -45,8 +45,11 @@ static char* gv(const char* p, const char* k) {
     free_config(c); return r;
 }
 static int lks(struct UTUN_INSTANCE* i) {
-    int n = 0; struct ETCP_CONN* c = i->connections;
-    while (c) { struct ETCP_LINK* l = c->links; while (l) { if (l->initialized && l->link_status) n++; l = l->next; } c = c->next; }
+    int n = 0; struct ll_entry* entry = i->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* c = ce->conn;
+        struct ETCP_LINK* l = c->links; while (l) { if (l->initialized && l->link_status) n++; l = l->next; }
+        entry = entry->next; }
     return n;
 }
 static void fail(const char* msg) { fprintf(stderr, "FAIL: %s\n", msg); fflush(stderr); result = 1; }
diff --git a/tests/test_etcp_dummynet.c b/tests/test_etcp_dummynet.c
index 77888be5..4bf3ed5d 100644
--- a/tests/test_etcp_dummynet.c
+++ b/tests/test_etcp_dummynet.c
@@ -81,8 +81,10 @@ static void send_pkt(void* arg) {
     if (sending_done || (now_us() - start_us)/1000 >= SEND_MS) {
         sending_done = 1; return;
     }
-    if (!client || !client->connections) return;
-    
+    if (!client || !client->connections || !client->connections->head) return;
+    struct ETCP_CONN* conn = ((struct conn_queue_entry*)client->connections->head->data)->conn;
+    if (!conn) return;
+
     struct ll_entry* e = ll_alloc_lldgram(sizeof(struct test_pkt));
     if (!e) return;
     struct test_pkt* pkt = (struct test_pkt*)e->dgram;
@@ -91,7 +93,7 @@ static void send_pkt(void* arg) {
     pkt->crc = crc32_calc(pkt->data, PAYLOAD_SIZE);
     e->len = sizeof(struct test_pkt);
     
-    if (etcp_send(client->connections, e) == 0) pkts_sent++;
+    if (etcp_send(conn, e) == 0) pkts_sent++;
     else queue_entry_free(e);
     
     /* Schedule next packet with 5ms delay for rate limiting (~200 pkt/sec)
@@ -229,7 +231,7 @@ int main(void) {
         
         /* Check if client has an established connection with ready links */
         if (client && client->connections) {
-            struct ETCP_CONN* conn = client->connections;
+            struct ETCP_CONN* conn = (client->connections && client->connections->head) ? ((struct conn_queue_entry*)client->connections->head->data)->conn : NULL;
             /* Check if peer_node_id is set (non-zero) and has links */
             if (conn->peer_node_id != 0 && conn->links != NULL) {
                 struct ETCP_LINK* link = conn->links;
diff --git a/tests/test_etcp_ping.c b/tests/test_etcp_ping.c
index 11e28031..03954cdc 100644
--- a/tests/test_etcp_ping.c
+++ b/tests/test_etcp_ping.c
@@ -97,27 +97,31 @@ static void monitor_connections(void* arg) {
     int server_links = 0;
     int client_links = 0;
     if (server_instance) {
-        struct ETCP_CONN* conn = server_instance->connections;
-        while (conn) {
+        struct ll_entry* e = server_instance->connections->head;
+        while (e) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            struct ETCP_CONN* conn = ce->conn;
             struct ETCP_LINK* link = conn->links;
             while (link) {
                 server_links++;
                 if (link->initialized) test_completed = 1;
                 link = link->next;
             }
-            conn = conn->next;
+            e = e->next;
         }
     }
     if (client_instance) {
-        struct ETCP_CONN* conn = client_instance->connections;
-        while (conn) {
+        struct ll_entry* e = client_instance->connections->head;
+        while (e) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            struct ETCP_CONN* conn = ce->conn;
             struct ETCP_LINK* link = conn->links;
             while (link) {
                 client_links++;
                 if (link->initialized) test_completed = 1;
                 link = link->next;
             }
-            conn = conn->next;
+            e = e->next;
         }
     }
     if (server_links > 0 && client_links > 0) test_completed = 1;
@@ -182,7 +186,7 @@ int main(void) {
         goto cleanup;
     }
     DEBUG_INFO(DEBUG_CATEGORY_ETCP, "Links established, running ping test");
-    struct ETCP_CONN* conn = client_instance->connections;
+    struct ETCP_CONN* conn = (client_instance->connections && client_instance->connections->head) ? ((struct conn_queue_entry*)client_instance->connections->head->data)->conn : NULL;
     if (conn && conn->links) {
         struct ETCP_LINK* link = conn->links;
         uint8_t peer_pubkey[SC_PUBKEY_SIZE];
diff --git a/tests/test_etcp_reconnect.c b/tests/test_etcp_reconnect.c
index a4107d59..5807858c 100644
--- a/tests/test_etcp_reconnect.c
+++ b/tests/test_etcp_reconnect.c
@@ -114,19 +114,22 @@ static void cleanup_temp_configs(void) {
 }
 
 static int is_connection_established(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        if (conn->initialized) return 1;
-        conn = conn->next;
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        if (ce->conn->initialized) return 1;
+        entry = entry->next;
     }
     return 0;
 }
 
 static void drain_received(int count_flag) {
-    if (!server_instance) return;
-    struct ETCP_CONN* conn = server_instance->connections;
-    while (conn) {
+    if (!server_instance || !server_instance->connections) return;
+    struct ll_entry* entry = server_instance->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         if (conn->output_queue) {
             queue_set_callback(conn->output_queue, NULL, NULL);
             struct ETCP_FRAGMENT* pkt;
@@ -136,13 +139,13 @@ static void drain_received(int count_flag) {
                 queue_entry_free((struct ll_entry*)pkt);
             }
         }
-        conn = conn->next;
+        entry = entry->next;
     }
 }
 
 static void send_packets(void) {
     if (!client_instance || packets_sent >= TOTAL_PACKETS) return;
-    struct ETCP_CONN* conn = client_instance->connections;
+    struct ETCP_CONN* conn = (client_instance->connections && client_instance->connections->head) ? ((struct conn_queue_entry*)client_instance->connections->head->data)->conn : NULL;
     if (!conn || !conn->input_queue) return;
     while (packets_sent < TOTAL_PACKETS) {
         if (queue_entry_count(conn->input_queue) >= MAX_QUEUE_SIZE) break;
@@ -160,7 +163,7 @@ static void monitor(void* arg) {
     int conn_ok = is_connection_established(client_instance);
     static int last_reinit_count = -1;
     int cur_reinit = 0;
-    struct ETCP_CONN* conn = client_instance ? client_instance->connections : NULL;
+    struct ETCP_CONN* conn = (client_instance && client_instance->connections && client_instance->connections->head) ? ((struct conn_queue_entry*)client_instance->connections->head->data)->conn : NULL;
     if (conn) cur_reinit = conn->reinit_count;
 
     switch (phase) {
@@ -208,8 +211,8 @@ static void monitor(void* arg) {
             }
             printf("Server recreated (node_id=%llx)\n", (unsigned long long)server_instance->node_id);
             // Force client to reinit — otherwise conn_ok stays true on old initialized=1
-            {   struct ETCP_CONN* c = client_instance->connections;
-                while (c) { etcp_conn_reinit(c); c = c->next; } }
+            {   struct ll_entry* e = client_instance->connections->head;
+                while (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data; etcp_conn_reinit(ce->conn); e = e->next; } }
             restart_action_done = 1;
         }
         drain_received(0);
diff --git a/tests/test_etcp_reinit_inflight.c b/tests/test_etcp_reinit_inflight.c
index 574f50d6..ef68d228 100644
--- a/tests/test_etcp_reinit_inflight.c
+++ b/tests/test_etcp_reinit_inflight.c
@@ -133,17 +133,20 @@ static void on_recv(struct ETCP_CONN* conn, struct ll_entry* entry) {
 }
 
 static int links_initialized(struct UTUN_INSTANCE* inst) {
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
+    if (!inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         struct ETCP_LINK* link = conn->links;
         while (link) { if (link->initialized) return 1; link = link->next; }
-        conn = conn->next;
+        entry = entry->next;
     }
     return 0;
 }
 
 static int buffers_full(struct test_ctx* ctx) {
-    struct ETCP_CONN* conn = ctx->sender->connections;
+    struct ETCP_CONN* conn = (ctx->sender->connections && ctx->sender->connections->head) ? ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn : NULL;
     if (!conn) return 0;
     struct ETCP_LINK* link = conn->links;
     return link && link->inflight_bytes >= link->inflight_lim_bytes
@@ -152,7 +155,7 @@ static int buffers_full(struct test_ctx* ctx) {
 }
 
 static void send_one_packet(struct test_ctx* ctx) {
-    struct ETCP_CONN* conn = ctx->sender->connections;
+    struct ETCP_CONN* conn = (ctx->sender->connections && ctx->sender->connections->head) ? ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn : NULL;
     if (!conn || !conn->initialized) return;
     if (ctx->total_packets_sent >= TOTAL_PACKETS) return;
     if (conn->input_queue && queue_entry_count(conn->input_queue) > 200) return;
@@ -192,11 +195,12 @@ static void monitor(void* arg) {
         break;
     case 2: // fill buffers
         if (buffers_full(ctx)) {
-            printf("  buffers full: inflight=%u/%u wait_ack=%d sent=%d\n",
-                   ctx->sender->connections->links->inflight_bytes,
-                   ctx->sender->connections->links->inflight_lim_bytes,
-                   ctx->sender->connections->input_wait_ack->count,
-                   ctx->total_packets_sent);
+            { struct ETCP_CONN* c = (ctx->sender->connections && ctx->sender->connections->head) ? ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn : NULL;
+              printf("  buffers full: inflight=%u/%u wait_ack=%d sent=%d\n",
+                     c ? c->links->inflight_bytes : 0,
+                     c ? c->links->inflight_lim_bytes : 0,
+                     c ? c->input_wait_ack->count : 0,
+                     ctx->total_packets_sent); }
             ctx->phase = 3;
         }
         break;
@@ -221,7 +225,7 @@ static void monitor(void* arg) {
         ctx->phase = 5;
         break;
     case 5: // wait delivery
-        conn = ctx->sender->connections;
+        conn = (ctx->sender->connections && ctx->sender->connections->head) ? ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn : NULL;
         if (conn && conn->reinit_count > 0 && !ctx->sender_reinit_detected) {
             ctx->sender_reinit_detected = 1;
             printf("  reinit detected (count=%u)\n", conn->reinit_count);
@@ -232,7 +236,7 @@ static void monitor(void* arg) {
         }
         break;
     case 6: // verify
-        conn = ctx->sender->connections;
+        conn = (ctx->sender->connections && ctx->sender->connections->head) ? ((struct conn_queue_entry*)ctx->sender->connections->head->data)->conn : NULL;
         if (conn && conn->reinit_count < 1) {
             printf("\n[FAIL] Reinit not triggered (reinit_count=%u)\n", conn->reinit_count);
             ctx->test_done = 2;
diff --git a/tests/test_etcp_router.c b/tests/test_etcp_router.c
index be97e9b5..3cc78608 100644
--- a/tests/test_etcp_router.c
+++ b/tests/test_etcp_router.c
@@ -205,8 +205,11 @@ static void write_configs(void) {
 
 // ======================== Helpers ========================
 static int conn_established(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    for (struct ETCP_CONN* c = inst->connections; c; c = c->next) {
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* c = ce->conn;
         for (struct ETCP_LINK* l = c->links; l; l = l->next) {
             if (l->initialized && c->crypto_ctx.initialized) {
                 int ok = 0;
@@ -215,6 +218,7 @@ static int conn_established(struct UTUN_INSTANCE* inst) {
                 if (ok) return 1;
             }
         }
+        entry = entry->next;
     }
     return 0;
 }
diff --git a/tests/test_etcp_router_reconnect.c b/tests/test_etcp_router_reconnect.c
index 9fb998fe..e130029d 100644
--- a/tests/test_etcp_router_reconnect.c
+++ b/tests/test_etcp_router_reconnect.c
@@ -186,9 +186,10 @@ static void state_step(void) {
         break;
     case ST_B_KILL:
         g_b->running=0; utun_instance_destroy(g_b); g_b=NULL;
-        {   struct ETCP_CONN *c,*n;
-            for(c=g_a->connections;c;c=n){n=c->next;if(c->peer_node_id==node_b)etcp_connection_close(c);}
-            for(c=g_c->connections;c;c=n){n=c->next;if(c->peer_node_id==node_b)etcp_connection_close(c);} }
+        {   struct ll_entry* e = queue_find_data_by_index(g_a->connections, (const uint8_t*)&node_b);
+            if (e) etcp_connection_close(((struct conn_queue_entry*)e->data)->conn);
+            e = queue_find_data_by_index(g_c->connections, (const uint8_t*)&node_b);
+            if (e) etcp_connection_close(((struct conn_queue_entry*)e->data)->conn); }
         g_phase_sent=0; g_bgp_ready_mask=0; g_state=ST_B_RESTART;
         break;
     case ST_B_RESTART:
diff --git a/tests/test_etcp_simple_traffic.c b/tests/test_etcp_simple_traffic.c
index 3495b152..7c9b66d3 100644
--- a/tests/test_etcp_simple_traffic.c
+++ b/tests/test_etcp_simple_traffic.c
@@ -107,22 +107,24 @@ static void cleanup_temp_configs(void) {
 }
 
 static int is_connection_established(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         struct ETCP_LINK* link = conn->links;
         while (link) {
             if (link->initialized) return 1;
             link = link->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return 0;
 }
 
 static void send_test_packet(void) {
     if (!client_instance || packet_sent) return;
-    struct ETCP_CONN* conn = client_instance->connections;
+    struct ETCP_CONN* conn = (client_instance->connections && client_instance->connections->head) ? ((struct conn_queue_entry*)client_instance->connections->head->data)->conn : NULL;
     if (!conn || !conn->input_queue) {
         DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "send_test_packet: no connection or input_queue");
         return;
@@ -138,7 +140,7 @@ static void send_test_packet(void) {
 
 static void check_packet_received(void) {
     if (!server_instance || packet_received) return;
-    struct ETCP_CONN* conn = server_instance->connections;
+    struct ETCP_CONN* conn = (server_instance->connections && server_instance->connections->head) ? ((struct conn_queue_entry*)server_instance->connections->head->data)->conn : NULL;
     if (!conn || !conn->output_queue) return;
 
     queue_set_callback(conn->output_queue, NULL, NULL);
diff --git a/tests/test_etcp_two_instances.c b/tests/test_etcp_two_instances.c
index 96304aed..f3b6b80d 100644
--- a/tests/test_etcp_two_instances.c
+++ b/tests/test_etcp_two_instances.c
@@ -125,8 +125,10 @@ static void monitor_connections(void* arg) {
     
     // Check server
     if (server_instance) {
-        struct ETCP_CONN* conn = server_instance->connections;
-        while (conn) {
+        struct ll_entry* entry = server_instance->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            struct ETCP_CONN* conn = ce->conn;
             struct ETCP_LINK* link = conn->links;
             while (link) {
                 server_links++;
@@ -136,14 +138,16 @@ static void monitor_connections(void* arg) {
                        link->is_server ? "server" : "client");
                 link = link->next;
             }
-            conn = conn->next;
+            entry = entry->next;
         }
     }
     
     // Check client
     if (client_instance) {
-        struct ETCP_CONN* conn = client_instance->connections;
-        while (conn) {
+        struct ll_entry* entry = client_instance->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            struct ETCP_CONN* conn = ce->conn;
             struct ETCP_LINK* link = conn->links;
             while (link) {
                 client_links++;
@@ -203,7 +207,7 @@ static void monitor_connections(void* arg) {
                 }
                 link = link->next;
             }
-            conn = conn->next;
+            entry = entry->next;
         }
     }
     
diff --git a/tests/test_icmp_proxy.c b/tests/test_icmp_proxy.c
index 5077a207..20334ee0 100644
--- a/tests/test_icmp_proxy.c
+++ b/tests/test_icmp_proxy.c
@@ -114,12 +114,18 @@ static void monitor(void* arg) {
 
     if (g_test_phase == 0) {
         int cli_ok = 0, exit_ok = 0;
-        for (struct ETCP_CONN* c = cli->connections; c; c = c->next)
+        { struct ll_entry* e = cli->connections->head;
+          while (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            struct ETCP_CONN* c = ce->conn;
             for (struct ETCP_LINK* l = c->links; l; l = l->next)
                 if (l->initialized && c->crypto_ctx.initialized) cli_ok = 1;
-        for (struct ETCP_CONN* c = exit_node->connections; c; c = c->next)
+            e = e->next; } }
+        { struct ll_entry* e = exit_node->connections->head;
+          while (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            struct ETCP_CONN* c = ce->conn;
             for (struct ETCP_LINK* l = c->links; l; l = l->next)
                 if (l->initialized && c->crypto_ctx.initialized) exit_ok = 1;
+            e = e->next; } }
         if (cli_ok && exit_ok) {
             g_test_phase = 1;
             // Override client handler for test verification
diff --git a/tests/test_ipv6_sockets.c b/tests/test_ipv6_sockets.c
index f0b9d161..ded353a7 100644
--- a/tests/test_ipv6_sockets.c
+++ b/tests/test_ipv6_sockets.c
@@ -121,15 +121,17 @@ static void cleanup_temp_configs(void) {
 }
 
 static int is_connection_established(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         struct ETCP_LINK* link = conn->links;
         while (link) {
             if (link->initialized) return 1;
             link = link->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return 0;
 }
diff --git a/tests/test_nat_detection.c b/tests/test_nat_detection.c
index f08a41ab..3d7986e7 100644
--- a/tests/test_nat_detection.c
+++ b/tests/test_nat_detection.c
@@ -149,27 +149,25 @@ static void cleanup_temp_configs(void) {
 }
 
 static int has_initialized_link(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         struct ETCP_LINK* link = conn->links;
         while (link) {
             if (link->initialized) return 1;
             link = link->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return 0;
 }
 
 static struct ETCP_LINK* find_link_to_node(struct UTUN_INSTANCE* inst, uint64_t node_id) {
-    if (!inst) return NULL;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        if (conn->peer_node_id == node_id) return conn->links;
-        conn = conn->next;
-    }
-    return NULL;
+    if (!inst || !inst->connections) return NULL;
+    struct ll_entry* entry = queue_find_data_by_index(inst->connections, (const uint8_t*)&node_id);
+    return entry ? ((struct conn_queue_entry*)entry->data)->conn->links : NULL;
 }
 
 static void test_timeout_cb(void* arg) {
@@ -335,11 +333,13 @@ int main(void) {
     }
 
     // Verify link nat_type on server
-    struct ETCP_CONN* conn_sc1 = inst_s->connections;
-    while (conn_sc1) {
-        if (conn_sc1->peer_node_id == NODE_ID_C1) break;
-        conn_sc1 = conn_sc1->next;
-    }
+    struct ETCP_CONN* conn_sc1 = NULL;
+    {   struct ll_entry* e = inst_s->connections->head;
+        while (e) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            if (ce->conn->peer_node_id == NODE_ID_C1) { conn_sc1 = ce->conn; break; }
+            e = e->next;
+        } }
     if (!link_sc1 || link_sc1->nat_type != NAT_TYPE_EIM) {
         DEBUG_ERROR(DEBUG_CATEGORY_BGP, "FAIL: link nat_type not EIM on server");
         goto cleanup;
@@ -414,10 +414,11 @@ int main(void) {
     // 6. Separate STUN check via explicit route_ping_send_req_addr
     DEBUG_INFO(DEBUG_CATEGORY_BGP, "Performing explicit STUN ping from S via C2 to C1...");
     struct ETCP_CONN* conn_sc2 = NULL;
-    struct ETCP_CONN* conn = inst_s->connections;
-    while (conn) {
-        if (conn->peer_node_id == NODE_ID_C2) { conn_sc2 = conn; break; }
-        conn = conn->next;
+    struct ll_entry* entry = inst_s->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        if (ce->conn->peer_node_id == NODE_ID_C2) { conn_sc2 = ce->conn; break; }
+        entry = entry->next;
     }
     if (!conn_sc2) {
         DEBUG_ERROR(DEBUG_CATEGORY_BGP, "FAIL: S has no connection to C2");
diff --git a/tests/test_nat_transport.c b/tests/test_nat_transport.c
index 15a57720..3f9e7ffe 100644
--- a/tests/test_nat_transport.c
+++ b/tests/test_nat_transport.c
@@ -157,11 +157,12 @@ static void test_timeout_cb(void* arg) {
 
 static struct ETCP_LINK* first_initialized_link(struct UTUN_INSTANCE* inst) {
     if (!inst || !inst->connections) return NULL;
-    struct ETCP_LINK* link = inst->connections->links;
-    while (link) {
-        if (link->initialized) return link;
-        link = link->next;
-    }
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
+        struct ETCP_LINK* link = conn->links;
+        while (link) { if (link->initialized) return link; link = link->next; }
+        entry = entry->next; }
     return NULL;
 }
 
@@ -278,7 +279,7 @@ static int test_provider_egress(void) {
     DEBUG_INFO(DEBUG_CATEGORY_NAT, "=== test_provider_egress ===");
 
     // Get the connection from client to provider (for debug info only)
-    struct ETCP_CONN* client_conn = inst_client->connections;
+    struct ETCP_CONN* client_conn = (inst_client->connections && inst_client->connections->head) ? ((struct conn_queue_entry*)inst_client->connections->head->data)->conn : NULL;
     if (!client_conn) {
         DEBUG_ERROR(DEBUG_CATEGORY_NAT, "No client connections");
         return 0;
diff --git a/tests/test_pkt_normalizer_etcp.c b/tests/test_pkt_normalizer_etcp.c
index e473d6fd..5312ef9d 100644
--- a/tests/test_pkt_normalizer_etcp.c
+++ b/tests/test_pkt_normalizer_etcp.c
@@ -127,9 +127,9 @@ static int verify_packet_data(uint8_t* buffer, int size, int expected_seq) {
 }
 
 static int is_connection_established(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) { struct ETCP_LINK* link = conn->links; while (link) { if (link->initialized) return 1; link = link->next; } conn = conn->next; }
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) { struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data; struct ETCP_CONN* conn = ce->conn; struct ETCP_LINK* link = conn->links; while (link) { if (link->initialized) return 1; link = link->next; } entry = entry->next; }
     return 0;
 }
 
@@ -189,16 +189,18 @@ static void monitor_and_send(void* arg) {
     if (!connection_checked) {
         if (is_connection_established(client_instance)) {
             connection_checked = 1;
-            if (!client_pn && client_instance->connections) {
-                client_pn = pn_init(client_instance->connections);
+            { struct ETCP_CONN* c = (client_instance->connections && client_instance->connections->head) ? ((struct conn_queue_entry*)client_instance->connections->head->data)->conn : NULL;
+              if (!client_pn && c) {
+                client_pn = pn_init(c);
                 if (!client_pn) { test_completed = 2; return; }
                 queue_set_callback(client_pn->output, NULL, NULL);
-            }
-            if (!server_pn && server_instance->connections) {
-                server_pn = pn_init(server_instance->connections);
+              } }
+            { struct ETCP_CONN* c = (server_instance->connections && server_instance->connections->head) ? ((struct conn_queue_entry*)server_instance->connections->head->data)->conn : NULL;
+              if (!server_pn && c) {
+                server_pn = pn_init(c);
                 if (!server_pn) { test_completed = 2; return; }
                 queue_set_callback(server_pn->output, NULL, NULL);
-            }
+              } }
         }
     }
 
diff --git a/tests/test_route_ping.c b/tests/test_route_ping.c
index 9a3d30ef..c3ce344c 100644
--- a/tests/test_route_ping.c
+++ b/tests/test_route_ping.c
@@ -157,27 +157,25 @@ static void cleanup_temp_configs(void) {
 }
 
 static int has_initialized_link(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* conn = ce->conn;
         struct ETCP_LINK* link = conn->links;
         while (link) {
             if (link->initialized) return 1;
             link = link->next;
         }
-        conn = conn->next;
+        entry = entry->next;
     }
     return 0;
 }
 
 static struct ETCP_CONN* find_conn_to_peer(struct UTUN_INSTANCE* inst, uint64_t peer_node_id) {
-    if (!inst) return NULL;
-    struct ETCP_CONN* conn = inst->connections;
-    while (conn) {
-        if (conn->peer_node_id == peer_node_id) return conn;
-        conn = conn->next;
-    }
-    return NULL;
+    if (!inst || !inst->connections) return NULL;
+    struct ll_entry* entry = queue_find_data_by_index(inst->connections, (const uint8_t*)&peer_node_id);
+    return entry ? ((struct conn_queue_entry*)entry->data)->conn : NULL;
 }
 
 static void test_timeout_cb(void* arg) {
diff --git a/tests/test_socks_http_proxy.c b/tests/test_socks_http_proxy.c
index ba468c0d..eb89db00 100644
--- a/tests/test_socks_http_proxy.c
+++ b/tests/test_socks_http_proxy.c
@@ -215,10 +215,15 @@ static char* make_cfg_client(void) {
 }
 
 static int conn_ready(struct UTUN_INSTANCE* inst) {
-    if (!inst) return 0;
-    for (struct ETCP_CONN* c = inst->connections; c; c = c->next)
+    if (!inst || !inst->connections) return 0;
+    struct ll_entry* entry = inst->connections->head;
+    while (entry) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+        struct ETCP_CONN* c = ce->conn;
         for (struct ETCP_LINK* l = c->links; l; l = l->next)
             if (l->initialized && c->crypto_ctx.initialized) return 1;
+        entry = entry->next;
+    }
     return 0;
 }
 
diff --git a/tests/test_stcp_traffic.c b/tests/test_stcp_traffic.c
index a1a72669..d015f0fe 100644
--- a/tests/test_stcp_traffic.c
+++ b/tests/test_stcp_traffic.c
@@ -178,8 +178,11 @@ int main(void) {
     TASSERT(cli_send_ready);
     TASSERT(cli_link);
 
-    { struct ETCP_CONN *c = srv_inst->connections;
-      while (c) { if (c->transport_link) { srv_link = (struct stcp_link *)c->transport_link; break; } c = c->next; }
+    { struct ll_entry* e = srv_inst->connections->head;
+      while (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+        struct ETCP_CONN *c = ce->conn;
+        if (c->transport_link) { srv_link = (struct stcp_link *)c->transport_link; break; }
+        e = e->next; }
     }
     TASSERT(srv_link);
 
diff --git a/tests/test_tcp_proxy_remote.c b/tests/test_tcp_proxy_remote.c
index 915af76b..a1536abc 100644
--- a/tests/test_tcp_proxy_remote.c
+++ b/tests/test_tcp_proxy_remote.c
@@ -118,10 +118,16 @@ static void monitor(void* arg) {
     if (g_done) return;
     if (g_phase == 0 && !g_conn_up) {
         int bup=0, eup=0;
-        if (g_b) for (struct ETCP_CONN*c=g_b->connections;c;c=c->next)
+        if (g_b) { struct ll_entry* e=g_b->connections->head;
+          while (e) { struct conn_queue_entry* ce=(struct conn_queue_entry*)e->data;
+            struct ETCP_CONN*c=ce->conn;
             for (struct ETCP_LINK*l=c->links;l;l=l->next) if (l->initialized&&c->crypto_ctx.initialized) bup=1;
-        if (g_exit) for (struct ETCP_CONN*c=g_exit->connections;c;c=c->next)
+            e=e->next; } }
+        if (g_exit) { struct ll_entry* e=g_exit->connections->head;
+          while (e) { struct conn_queue_entry* ce=(struct conn_queue_entry*)e->data;
+            struct ETCP_CONN*c=ce->conn;
             for (struct ETCP_LINK*l=c->links;l;l=l->next) if (l->initialized&&c->crypto_ctx.initialized) eup=1;
+            e=e->next; } }
         if (bup && eup) { g_conn_up=1; start_test(); }
     }
     if (g_conn_up && !g_done) poll_test();
diff --git a/tests/test_udp_proxy.c b/tests/test_udp_proxy.c
index 15e19a0c..3dc96613 100644
--- a/tests/test_udp_proxy.c
+++ b/tests/test_udp_proxy.c
@@ -118,12 +118,18 @@ static void monitor(void* arg) {
     if (g_test_phase == 0) {
         // Wait for ETCP connection
         int cli_ok = 0, exit_ok = 0;
-        for (struct ETCP_CONN* c = cli->connections; c; c = c->next)
+        { struct ll_entry* e = cli->connections->head;
+          while (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            struct ETCP_CONN* c = ce->conn;
             for (struct ETCP_LINK* l = c->links; l; l = l->next)
                 if (l->initialized && c->crypto_ctx.initialized) cli_ok = 1;
-        for (struct ETCP_CONN* c = exit_node->connections; c; c = c->next)
+            e = e->next; } }
+        { struct ll_entry* e = exit_node->connections->head;
+          while (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+            struct ETCP_CONN* c = ce->conn;
             for (struct ETCP_LINK* l = c->links; l; l = l->next)
                 if (l->initialized && c->crypto_ctx.initialized) exit_ok = 1;
+            e = e->next; } }
         if (cli_ok && exit_ok) {
             g_test_phase = 1;
             // Bind client handler for UDP replies (overrides what tcp_proxy_client_create set, for test verification)
diff --git a/tools/chatgui/transport/chat_core.c b/tools/chatgui/transport/chat_core.c
index 0016561a..362fa204 100644
--- a/tools/chatgui/transport/chat_core.c
+++ b/tools/chatgui/transport/chat_core.c
@@ -564,10 +564,6 @@ struct cc_parallel_ctx {
 
 static void cc_parallel_cleanup(struct cc_parallel_state* st) {
     if (!st) return;
-    if (st->inst && st->inst->chat_connections) {
-        struct ll_entry* e = queue_find_data_by_index(st->inst->chat_connections, (const uint8_t*)&st->node_id);
-        if (e) { queue_remove_data(st->inst->chat_connections, e); queue_entry_free(e); }
-    }
     u_free(st->conns);
     u_free(st->timers);
     u_free(st);
@@ -764,8 +760,7 @@ void chat_core_connect_from_invite(struct chat_invite* inv) {
             pst->conns[idx] = NULL; pst->timers[idx] = NULL; pst->pending_count--; continue;
         }
         pst->conns[idx] = conn;
-        conn->peer_node_id = inv->node_id;
-        { struct ll_entry* qe = queue_entry_new(16); if (qe) { *(uint64_t*)qe->data = inv->node_id; *(struct ETCP_CONN**)(qe->data+8) = conn; queue_data_put_with_index(g_cc.inst->chat_connections, qe); } }
+        etcp_conn_set_peer_node_id(conn, inv->node_id);
         pst->timers[idx] = uasync_set_timeout(g_cc.inst->ua, CC_PARALLEL_CONNECT_TIMEOUT_MS * 10,
                                                pctx, cc_parallel_timeout_cb, "cc_parallel");
         DEBUG_INFO(DEBUG_CATEGORY_CONNECTIVITY, "%s: parallel connect attempt %d/%d to %d.%d.%d.%d:%d",
@@ -810,10 +805,6 @@ struct ca_state {
 
 static void ca_cleanup(struct ca_state* st) {
     if (!st) return;
-    if (st->inst && st->inst->chat_connections) {
-        struct ll_entry* e = queue_find_data_by_index(st->inst->chat_connections, (const uint8_t*)&st->node_id);
-        if (e) { queue_remove_data(st->inst->chat_connections, e); queue_entry_free(e); }
-    }
     if (st->ctxs) { for (int i = 0; i < st->addr_count; i++) u_free(st->ctxs[i]); u_free(st->ctxs); }
     u_free(st->conns);
     u_free(st->timers);
@@ -962,10 +953,7 @@ void chat_core_connect_auto(uint64_t node_id,
         }
         sc_init_ctx(&conn->crypto_ctx, &g_cc.inst->my_keys);
         sc_set_peer_public_key(&conn->crypto_ctx, pubkey, 0);
-        conn->peer_node_id = node_id;
-        conn->next = g_cc.inst->connections;
-        g_cc.inst->connections = conn;
-        g_cc.inst->connections_count++;
+        etcp_conn_set_peer_node_id(conn, node_id);
 
         struct ca_ctx* pctx = u_calloc(1, sizeof(struct ca_ctx));
         if (!pctx) { etcp_connection_close(conn); pst->conns[i] = NULL; pst->timers[i] = NULL; pst->ctxs[i] = NULL; pst->pending_count--; continue; }
@@ -980,7 +968,6 @@ void chat_core_connect_auto(uint64_t node_id,
             pst->conns[i] = NULL; pst->timers[i] = NULL; pst->ctxs[i] = NULL; pst->pending_count--; continue;
         }
         pst->conns[i] = conn;
-        { struct ll_entry* qe = queue_entry_new(16); if (qe) { *(uint64_t*)qe->data = node_id; *(struct ETCP_CONN**)(qe->data+8) = conn; queue_data_put_with_index(g_cc.inst->chat_connections, qe); } }
         pst->timers[i] = uasync_set_timeout(g_cc.inst->ua, CA_CONNECT_TIMEOUT_MS * 10,
                                              pctx, ca_timeout_cb, "ca_timeout");
         DEBUG_INFO(DEBUG_CATEGORY_CONNECTIVITY, "%s: auto_connect attempt %d/%d to %d.%d.%d.%d:%d",
diff --git a/tools/chatgui/transport/chat_sync.c b/tools/chatgui/transport/chat_sync.c
index a6a679d8..d91f6124 100644
--- a/tools/chatgui/transport/chat_sync.c
+++ b/tools/chatgui/transport/chat_sync.c
@@ -90,15 +90,18 @@ static void ac_gc(struct auto_connect* ac) {
         if (now - ac->flights[i].created_tb < deadline) continue;
         uint64_t nid = ac->flights[i].node_id;
         /* check if link already UP — if so, just free slot (already connected) */
-        struct ETCP_CONN* c = ac->inst->connections;
         int found_up = 0;
-        while (c) {
-            if (c->peer_node_id == nid) {
-                struct ETCP_LINK* l = c->links;
-                while (l) { if (l->initialized && l->link_status) { found_up = 1; break; } l = l->next; }
-                if (found_up) break;
+        {
+            struct ll_entry* entry = ac->inst->connections->head;
+            while (entry) {
+                struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+                if (ce->conn->peer_node_id == nid) {
+                    struct ETCP_LINK* l = ce->conn->links;
+                    while (l) { if (l->initialized && l->link_status) { found_up = 1; break; } l = l->next; }
+                    if (found_up) break;
+                }
+                entry = entry->next;
             }
-            c = c->next;
         }
         if (found_up) {
             chat_core_connect_auto_cancel(ac->flights[i].ca_state);
@@ -130,12 +133,9 @@ static int ac_find_free_slot(struct auto_connect* ac) {
 /* ── check if node already has active ETCP connection ── */
 
 static int ac_node_has_conn(struct UTUN_INSTANCE* inst, uint64_t nid) {
-    struct ETCP_CONN* c = inst->connections;
-    while (c) {
-        if (c->peer_node_id == nid) return 1;
-        c = c->next;
-    }
-    return 0;
+    if (!inst->connections) return 0;
+    struct ll_entry* e = queue_find_data_by_index(inst->connections, (const uint8_t*)&nid);
+    return e != NULL;
 }
 
 /* ── fill up to AC_MAX_FLIGHTS by advancing cursor ── */
@@ -433,24 +433,22 @@ static void cs_join_timeout_cb(void* arg) {
 
 /* ── helper: find active ETCP_CONN for node ── */
 
-struct CHAT_CONN_ENTRY { uint64_t node_id; struct ETCP_CONN* conn; };
-
 static struct ETCP_CONN* cs_find_conn_for_node(struct UTUN_INSTANCE* inst, uint64_t node_id) {
-    struct ll_entry* e = queue_find_data_by_index(inst->chat_connections, (const uint8_t*)&node_id);
-    if (e) { struct CHAT_CONN_ENTRY* ce = (struct CHAT_CONN_ENTRY*)e->data; if (ce->conn->initialized && ce->conn->links_up) return ce->conn; }
+    if (!inst->connections) return NULL;
+    struct ll_entry* e = queue_find_data_by_index(inst->connections, (const uint8_t*)&node_id);
+    if (e) { struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data; if (ce->conn->initialized && ce->conn->links_up) return ce->conn; }
     return NULL;
 }
 
 /* ── helper: check if peer has active ETCP link ── */
 
 static int cs_is_peer_online(struct UTUN_INSTANCE* inst, uint64_t peer_id) {
-    struct ETCP_CONN* c = inst->connections;
-    while (c) {
-        if (c->peer_node_id == peer_id) {
-            struct ETCP_LINK* l = c->links;
-            while (l) { if (l->initialized && l->link_status) return 1; l = l->next; }
-        }
-        c = c->next;
+    if (!inst->connections) return 0;
+    struct ll_entry* e = queue_find_data_by_index(inst->connections, (const uint8_t*)&peer_id);
+    if (e) {
+        struct conn_queue_entry* ce = (struct conn_queue_entry*)e->data;
+        struct ETCP_LINK* l = ce->conn->links;
+        while (l) { if (l->initialized && l->link_status) return 1; l = l->next; }
     }
     return 0;
 }
@@ -509,10 +507,6 @@ static void cs_on_conn_down(struct ETCP_CONN* conn, void* arg) {
     (void)arg;
     if (!conn || !g_cs) return;
     uint64_t peer = conn->peer_node_id;
-    if (g_cs->inst->chat_connections) {
-        struct ll_entry* e = queue_find_data_by_index(g_cs->inst->chat_connections, (const uint8_t*)&peer);
-        if (e) { queue_remove_data(g_cs->inst->chat_connections, e); queue_entry_free(e); }
-    }
     uint16_t rtt = conn->rtt_avg_100;
     if (rtt > 0 && peer != 0 && g_cs->inst->topo_groups && g_cs->inst->topo_groups->topo_sqlite_db) {
         sqlite3* db = g_cs->inst->topo_groups->topo_sqlite_db;
@@ -617,13 +611,14 @@ int chat_sync_init(struct UTUN_INSTANCE* inst,
     etcp_bind(inst, ETCP_RT_ID_CHAT_SYNC, chat_sync_recv_cb);
     etcp_add_new_conn_cbk(inst, cs_on_new_conn, NULL);
 
-    inst->chat_connections = queue_new(inst->ua, 16, 0, 8, "chat_conns");
-
-    struct ETCP_CONN* c = inst->connections;
-    while (c) {
-        etcp_conn_add_up_cbk(c, cs_on_conn_up, NULL);
-        etcp_conn_add_down_cbk(c, cs_on_conn_down, NULL);
-        c = c->next;
+    {
+        struct ll_entry* entry = inst->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            etcp_conn_add_up_cbk(ce->conn, cs_on_conn_up, NULL);
+            etcp_conn_add_down_cbk(ce->conn, cs_on_conn_down, NULL);
+            entry = entry->next;
+        }
     }
 
     cs_refresh_channels(cs);
@@ -646,17 +641,18 @@ void chat_sync_destroy(struct UTUN_INSTANCE* inst) {
     member_sync_destroy(inst);
     cs->initialized = 0; g_cs = NULL;
 
-    queue_free(inst->chat_connections); inst->chat_connections = NULL;
-
     etcp_unbind(inst, ETCP_RT_ID_CHAT_SYNC);
     if (cs->refresh_timer) { uasync_cancel_timeout(inst->ua, cs->refresh_timer); cs->refresh_timer = NULL; }
     cs_cancel_proto_timers(cs);
 
-    struct ETCP_CONN* c = inst->connections;
-    while (c) {
-        etcp_conn_remove_up_cbk(c, cs_on_conn_up, NULL);
-        etcp_conn_remove_down_cbk(c, cs_on_conn_down, NULL);
-        c = c->next;
+    {
+        struct ll_entry* entry = inst->connections->head;
+        while (entry) {
+            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
+            etcp_conn_remove_up_cbk(ce->conn, cs_on_conn_up, NULL);
+            etcp_conn_remove_down_cbk(ce->conn, cs_on_conn_down, NULL);
+            entry = entry->next;
+        }
     }
 
     for (int i = 0; i < cs->channel_count; i++)