Add command ``SetOption41 <x>`` to force sending gratuitous ARP every <x> seconds

tasmota/CHANGELOG.md

@@ -13,6 +13,7 @@
 - Add command ``Sensor10 31..254`` to control BH1750 measurement time which defaults to 69 (#8016)
 - Add command ``SetOption91 1`` to enable fading at startup / power on
 - Add quick wifi connect using saved AP parameters when ``SetOption56 0`` (#3189)
+- Add command ``SetOption41 <x>`` to force sending gratuitous ARP every <x> seconds
 
 ### 8.2.0.2 20200328
 

tasmota/settings.ino

@@ -1298,8 +1298,8 @@ void SettingsDelta(void)
         Settings.tuya_fnid_map[tuyaindex].dpid = 1;
         tuyaindex++;
       }
-      if (Settings.param[P_ex_TUYA_RELAYS] > 0) {
-        for (uint8_t i = 0 ; i < Settings.param[P_ex_TUYA_RELAYS]; i++) {  // ex SetOption41
+      if (Settings.param[P_ARP_GRATUITOUS] > 0) {            // Was P_ex_TUYA_RELAYS
+        for (uint8_t i = 0 ; i < Settings.param[P_ARP_GRATUITOUS]; i++) {  // ex SetOption41
           Settings.tuya_fnid_map[tuyaindex].fnid = 12 + i;   // TUYA_MCU_FUNC_REL2 -  Create FnID for Switches
           Settings.tuya_fnid_map[tuyaindex].dpid = i + 2;
           tuyaindex++;

tasmota/support_tasmota.ino

@@ -814,6 +814,9 @@ void PerformEverySecond(void)
       }
     }
   }
+
+  // Wifi keep alive to send Gratuitous ARP
+  wifiKeepAlive();
 }
 
 /*-------------------------------------------------------------------------------------------*\

tasmota/support_wifi.ino

@@ -708,3 +708,51 @@ void EspRestart(void)
 //  ESP.restart();            // This results in exception 3 on restarts on core 2.3.0
   ESP.reset();
 }
+
+//
+// Gratuitous ARP, backported from https://github.com/esp8266/Arduino/pull/6889
+//
+extern "C" {
+#if LWIP_VERSION_MAJOR == 1
+#include "netif/wlan_lwip_if.h" // eagle_lwip_getif()
+#include "netif/etharp.h" // gratuitous arp
+#else
+#include "lwip/etharp.h" // gratuitous arp
+#endif
+}
+
+unsigned long wifiTimer = 0;
+
+void stationKeepAliveNow(void) {
+  AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_WIFI "Sending Gratuitous ARP"));
+  for (netif* interface = netif_list; interface != nullptr; interface = interface->next)
+    if (
+          (interface->flags & NETIF_FLAG_LINK_UP)
+      && (interface->flags & NETIF_FLAG_UP)
+#if LWIP_VERSION_MAJOR == 1
+      && interface == eagle_lwip_getif(STATION_IF) /* lwip1 does not set if->num properly */
+      && (!ip_addr_isany(&interface->ip_addr))
+#else
+      && interface->num == STATION_IF
+      && (!ip4_addr_isany_val(*netif_ip4_addr(interface)))
+#endif
+  )
+  {
+    etharp_gratuitous(interface);
+    break;
+  }
+}
+
+void wifiKeepAlive(void) {
+  uint32_t wifiTimerSec = Settings.param[P_ARP_GRATUITOUS];   // 8-bits number of seconds, or minutes if > 100
+
+  if ((WL_CONNECTED != Wifi.status) || (0 == wifiTimerSec)) { return; }   // quick exit if wifi not connected or feature disabled
+
+  if (wifiTimerSec > 100) {
+    wifiTimerSec = (wifiTimerSec - 100) * 60;                 // convert >100 as minutes, ex: 105 = 5 minutes, 110 = 10 minutes
+  }
+  if (TimeReached(wifiTimer)) {
+    stationKeepAliveNow();
+    SetNextTimeInterval(wifiTimer, wifiTimerSec * 1000);
+  }
+}

tasmota/tasmota.h

@@ -256,7 +256,7 @@ enum ButtonStates { PRESSED, NOT_PRESSED };
 enum Shortcuts { SC_CLEAR, SC_DEFAULT, SC_USER };
 
 enum SettingsParamIndex { P_HOLD_TIME, P_MAX_POWER_RETRY, P_BACKLOG_DELAY, P_MDNS_DELAYED_START, P_BOOT_LOOP_OFFSET, P_RGB_REMAP, P_IR_UNKNOW_THRESHOLD,  // SetOption32 .. SetOption38
-                          P_CSE7766_INVALID_POWER, P_HOLD_IGNORE, P_ex_TUYA_RELAYS, P_OVER_TEMP,  // SetOption39 .. SetOption42
+                          P_CSE7766_INVALID_POWER, P_HOLD_IGNORE, P_ARP_GRATUITOUS, P_OVER_TEMP,  // SetOption39 .. SetOption42
                           P_ex_DIMMER_MAX, P_ex_TUYA_VOLTAGE_ID, P_ex_TUYA_CURRENT_ID, P_ex_TUYA_POWER_ID,  // SetOption43 .. SetOption46
                           P_ex_ENERGY_TARIFF1, P_ex_ENERGY_TARIFF2,  // SetOption47 .. SetOption48
                           P_MAX_PARAM8 };  // Max is PARAM8_SIZE (18) - SetOption32 until SetOption49