[wifi] Connect LN882x to the BSSID asked for (#20174)

esphome/components/wifi/__init__.py

@@ -734,6 +734,10 @@ async def to_code(config):
     if not config[CONF_ENABLE_ON_BOOT]:
         cg.add(var.set_enable_on_boot(False))
 
+    # LN882x: hand the SDK the BSSID LibreTiny 1.13 drops (see wifi_component_libretiny.cpp); remove once fixed upstream.
+    if CORE.is_ln882x:
+        cg.add_build_flag("-Wl,--wrap=wifi_sta_connect")
+
     # post_connect_roaming defaults to true in C++ - disable if user disabled it
     # or if 802.11k/v is enabled (driver handles roaming natively)
     if (

esphome/components/wifi/wifi_component_libretiny.cpp

@@ -31,6 +31,17 @@ extern "C" {
 #ifdef USE_LN882X
 #include <WiFiPrivate.h>
 #undef DATA  // clashes with setup_priority::DATA
+// LibreTiny 1.13's LN882H reconnect() gives the SDK a NULL bssid; pass on the requested one. Remove once it passes
+// info.bssid. Safe without a BSSID: begin() frees sta.bssid (resetNetworkInfo), so it stays NULL.
+// NOLINTBEGIN(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp,readability-identifier-naming)
+// Names are mandated by the --wrap linker mechanism.
+extern "C" int __real_wifi_sta_connect(wifi_sta_connect_t *connect, wifi_scan_cfg_t *scan_cfg);
+extern "C" int __wrap_wifi_sta_connect(wifi_sta_connect_t *connect, wifi_scan_cfg_t *scan_cfg) {
+  if (connect->bssid == nullptr)
+    connect->bssid = static_cast<WiFiData *>(WiFi.data)->sta.bssid;
+  return __real_wifi_sta_connect(connect, scan_cfg);
+}
+// NOLINTEND(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp,readability-identifier-naming)
 #endif
 
 #include "esphome/core/application.h"