nat: use same-interface STUN mapping as tentative EIM

src/routing_layer/nat_detection.c

@@ -16,6 +16,7 @@
 #include "etcp_router.h"
 #include "route_crypto.h"
 #include "stcp_client.h"
+#include "stun_nat.h"
 #include "sock_match.h"
 #include "../lib/debug_config.h"
 #include "../lib/mem.h"
@@ -574,7 +575,7 @@ static void clear_profile(struct nat_socket *state, uint8_t reason) {
     }
 }
 
-/* Публикуется только измерение рабочего endpoint; отдельный STUN-порт остаётся диагностикой. */
+/* Измерение рабочего endpoint приоритетно; STUN того же пути даёт только предварительный EIM?. */
 static void select_profile(struct nat_socket *state) {
     const struct address_profile *current = &state->socket->address_profile;
     struct address_profile selected = state->measured_profile;
@@ -586,6 +587,15 @@ static void select_profile(struct nat_socket *state) {
     if (!selected.mapping && state->observed_address.ss_family) {
         selected.source = ADDRESS_SOURCE_ETCP; selected_address = state->observed_address;
     }
+    struct stun_nat_result stun;
+    uint64_t now = get_time_tb();
+    if (!selected.mapping && !stun_nat_get_socket_result(state->detector->instance, state->socket, &stun) &&
+        (stun.status == STUN_NAT_COMPLETE || stun.status == STUN_NAT_PARTIAL) &&
+        stun.measured_at_tb && now >= stun.measured_at_tb && now - stun.measured_at_tb < STUN_NAT_TTL_TB &&
+        stun.server_count == 2 && stun.translated == 1 && (stun.mapping == STUN_MAP_MATCH || stun.mapping == STUN_MAP_EIM) &&
+        (!selected_address.ss_family || route_ping_addr_equal(&selected_address, &stun.mapped[0], 0))) {
+        selected.mapping = ADDRESS_MAP_EIM; selected.inbound = ADDRESS_IN_UNKNOWN; selected.source = ADDRESS_SOURCE_STUN;
+    }
     int address_changed = selected_address.ss_family != state->socket->nat_addr.ss_family ||
         (selected_address.ss_family && !route_ping_addr_equal(&selected_address, &state->socket->nat_addr, 1));
     if (selected.mapping == current->mapping && selected.inbound == current->inbound &&