router close_all_for_node: integrate with BGP remove_conn, fail fast on no route, stop PAUSE cycle

- route_bgp_remove_conn: call etcp_router_conn_close_all_for_node() when node loses all paths
- etcp_route_send: check BGP route before creating conn (return -1 early, no conn leak)
- remote_proxy: check rp_send_msg return value, close conn on error to break PAUSE↔FLUSH cycle

src/etcp_router.c

@@ -486,6 +486,14 @@ int etcp_route_send(struct UTUN_INSTANCE* inst, uint64_t dst_node_id, struct ll_
         return 0;
     }
 
+    struct ETCP_CONN* etcp_conn = route_bgp_find_conn_for_node(inst->bgp, dst_node_id);
+    if (!etcp_conn) {
+        DEBUG_WARN(DEBUG_CATEGORY_ETCP, "etcp_route_send: no BGP route to %016llx svc_id=%u, dropping",
+                   (unsigned long long)dst_node_id, svc_id);
+        queue_dgram_free(entry); queue_entry_free(entry);
+        return -1;
+    }
+
     struct ETCP_ROUTER_CONN* rconn = etcp_router_conn_get(inst, dst_node_id, svc_id);
     if (!rconn) { queue_dgram_free(entry); queue_entry_free(entry); return -1; }
 

src/remote_proxy.c

@@ -141,7 +141,10 @@ static void rp_sock_pause_cb(void* arg) {
     }
     if (rc->pause_buf && rc->pause_len > 0) {
         DEBUG_INFO(DEBUG_CATEGORY_SOCKET, "SOCK:PAUSE_FLUSH fd=%d sid=%08x len=%zu qcnt=%d", (int)rc->sock, rc->stream_id, rc->pause_len, qcnt);
-        rp_send_msg(inst, rc->peer_node_id, TCP_PROXY_SUBCMD_DATA, rc->stream_id, rc->pause_buf, rc->pause_len);
+        if (rp_send_msg(inst, rc->peer_node_id, TCP_PROXY_SUBCMD_DATA, rc->stream_id, rc->pause_buf, rc->pause_len) < 0) {
+            DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "SOCK:PAUSE_FLUSH send failed — closing sid=%08x", rc->stream_id);
+            rc->error = 1; u_free(rc->pause_buf); rc->pause_buf = NULL; rc->pause_len = 0; rp_conn_free(rc); return;
+        }
         u_free(rc->pause_buf); rc->pause_buf = NULL; rc->pause_len = 0;
     }
     rc->read_id = uasync_add_socket_t(rc->ua, rc->sock, rp_sock_read_cb, rp_sock_write_cb, rp_sock_error_cb, rc);
@@ -171,7 +174,10 @@ static void rp_sock_read_cb(socket_t sock, void* arg) {
             return;
         }
         DEBUG_INFO(DEBUG_CATEGORY_SOCKET, "SOCK:RECV fd=%d sid=%08x len=%zd total=%d", (int)rc->sock, rc->stream_id, n, rp_conn_total(rc));
-        rp_send_msg(inst, rc->peer_node_id, TCP_PROXY_SUBCMD_DATA, rc->stream_id, buf, (size_t)n);
+        if (rp_send_msg(inst, rc->peer_node_id, TCP_PROXY_SUBCMD_DATA, rc->stream_id, buf, (size_t)n) < 0) {
+            DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "SOCK:RECV send failed — closing sid=%08x", rc->stream_id);
+            rc->error = 1; rp_conn_free(rc); return;
+        }
     } else if (n == 0) {
         DEBUG_INFO(DEBUG_CATEGORY_SOCKET, "SOCK:EOF fd=%d sid=%08x total=%d cli_closed=%d sock_closed=%d",
                    (int)rc->sock, rc->stream_id, rp_conn_total(rc), rc->cli_closed, rc->sock_closed);

src/route_bgp.c

@@ -436,6 +436,7 @@ void route_bgp_remove_conn(struct ETCP_CONN* conn) {
             struct ll_entry* entry = node_entry;
             if (entry) { queue_remove_data(bgp->nodes, entry); queue_entry_free(entry); }
             nodes_removed++;
+            etcp_router_conn_close_all_for_node(bgp->instance, key);
             DEBUG_DEBUG(DEBUG_CATEGORY_BGP, "Removed node %016llx after link down", (unsigned long long)key);
         }
         node_entry = next;