Expose per-service payload backlog and acknowledged delivery

src/routing_layer/etcp_router.c

@@ -564,6 +564,7 @@ static int router_conn_reset(struct ETCP_ROUTER_CONN* rconn) {
     rconn->c_ack_sent = 0; rconn->c_ack_recv = 0; rconn->c_retrans_done = 0;
     rconn->c_dup_dropped = 0; rconn->c_oob_dropped = 0; rconn->c_stale_ack = 0; rconn->c_sign_fail = 0;
     rconn->last_ack_changed_tb = 0;
+    route_tx_meter_reset(&rconn->delivery, get_time_us());
     return 0;
 }
 
@@ -666,7 +667,7 @@ static void router_send_drain_cb(struct ll_queue* q, void* arg) {
         free_entry(e); u_free(inf->dgram); u_free(inf); return;
     }
     memcpy(e->dgram, inf->dgram, len); e->len = len;
-    memcpy(&inf->seq, pending->data, 4); inf->ll.size = 4;
+    memcpy(&inf->seq, pending->data, 4); inf->ll.size = 4; inf->ll.len = pending->len;
     inf->dgram_len = len; inf->last_sent_tb = get_time_tb(); inf->send_count = 1;
     uint32_t seq = inf->seq;
     queue_data_put_with_index(rconn->inflight_q, &inf->ll);
@@ -1210,6 +1211,7 @@ static void router_handle_ack(struct UTUN_INSTANCE* inst, struct ETCP_ROUTER_CON
     while (rconn->inflight_q->head) {
         struct ROUTER_INFLIGHT* inf = (struct ROUTER_INFLIGHT*)rconn->inflight_q->head;
         if ((int32_t)(inf->seq - seq) >= 0) break;
+        route_tx_meter_ack(&rconn->delivery, get_time_us(), inf->ll.len);
         queue_remove_data(rconn->inflight_q, &inf->ll);
         u_free(inf->dgram); u_free(inf);
     }
@@ -1548,6 +1550,27 @@ void etcp_router_conn_restart(struct UTUN_INSTANCE* inst, uint64_t group_id, uin
     if (!rconn->closed) router_handshake_start(rconn);
 }
 
+/* Снимок логической доставки: физические копии inflight второй раз не учитываются. */
+int etcp_router_tx_stats(struct UTUN_INSTANCE *inst, uint64_t group, uint64_t peer, uint8_t svc,
+                         uint64_t now_us, struct ETCP_ROUTER_TX_STATS *out) {
+    if (!inst || !out) { DEBUG_ERROR(DEBUG_CATEGORY_ETCPROUTE, "router TX snapshot invalid arguments"); return -1; }
+    struct ETCP_ROUTER_CONN *rconn = router_conn_find(inst, group, peer, svc);
+    if (!rconn || rconn->closed) { memset(out, 0, sizeof(*out)); return 1; }
+    struct ETCP_ROUTER_TX_STATS result = {
+        .local_epoch = rconn->reset_id, .peer_epoch = rconn->peer_reset_id,
+        .queued_bytes = rconn->send_q->total_bytes, .inflight_bytes = rconn->inflight_q->total_bytes,
+        .queued_packets = rconn->send_q->count, .inflight_packets = rconn->inflight_q->count,
+        .acked_bytes = rconn->delivery.bytes, .acked_packets = rconn->delivery.packets,
+        .rtt_us = (uint32_t)rconn->rtt * 100,
+        .baseline_rtt_us = rconn->minrtt_window_count ? (uint32_t)rconn->minrtt * 100 : 0,
+        .ready = rconn->peer_reset_id != 0, .no_route = rconn->no_route,
+        .receive_busy = rconn->peer_receive_blocked, .probing = rconn->minrtt_probe
+    };
+    if (route_tx_meter_window(&rconn->delivery, now_us, &result.window) < 0) return -1;
+    *out = result;
+    return 0;
+}
+
 // Backpressure: зарегистрировать waiter на send_q для (group_id, node_id, svc_id).
 void etcp_router_on_send_ready(struct UTUN_INSTANCE* inst, uint64_t group_id, uint64_t node_id, uint8_t svc_id,
                                 struct queue_waiter_handle* h,

src/routing_layer/etcp_router.h

@@ -34,6 +34,7 @@ extern "C" {
 
 #include <stdint.h>
 #include "etcp_api.h"
+#include "route_tx_stats.h"
 
 // ====================================================================
 // 1. Протокол SVC_ROUTE (wire-формат и формат доставки в сервис)
@@ -179,8 +180,23 @@ struct ETCP_ROUTER_CONN {
     uint32_t c_oob_dropped;      // дропнуто out-of-bounds seq
     uint32_t c_stale_ack;        // устаревших ACK
     uint32_t c_sign_fail;        // signature verification failures
+    struct route_tx_meter delivery; // первые подтверждения исходного payload, без wire overhead
 };
 
+/* Заимствований нет. queued/inflight — исходный payload, а не размер криптограммы.
+ * ACK подтверждает доставку callback сервиса; декодирование/показ сервис отслеживает отдельно. */
+struct ETCP_ROUTER_TX_STATS {
+    uint64_t local_epoch, peer_epoch, queued_bytes, inflight_bytes, acked_bytes, acked_packets;
+    uint32_t queued_packets, inflight_packets;
+    struct route_tx_window window;
+    uint32_t rtt_us, baseline_rtt_us;
+    int ready, no_route, receive_busy, probing;
+};
+
+/* Только uasync. 0 — снимок, 1 — канал отсутствует/закрыт, -1 — неверные аргументы. Канал не создаёт. */
+int etcp_router_tx_stats(struct UTUN_INSTANCE *inst, uint64_t group, uint64_t peer, uint8_t svc,
+                         uint64_t now_us, struct ETCP_ROUTER_TX_STATS *out);
+
 #define ROUTER_CONN_HASH_SIZE     256
 #define ROUTER_RECVQ_HASH_SIZE    1024
 #define ROUTER_MAX_INFLIGHT       256    // макс пакетов в полёте (для контроля inflight)