Test: etharp_gratuitous (#1877)

* test: etharp_gratuitous * proper checks before calling etharp_gratuitous, move includes * disable at runtime * ms values * reload * debug * reword * filter by ifnum instead of checking for AP mode * drop station_if check 2.3.0/lwip1 builds netif->num increments on for each sta or ap lwip2 keeps those constant, but that seems like a implementation detail might break in the future anyways...
xoseperez · Aug 30, 2019 · 35ce687 · 35ce687
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diff --git a/code/espurna/config/general.h b/code/espurna/config/general.h
@@ -554,6 +554,25 @@
 #define WIFI_PROPAGATION_CONST 4 // This is typically something between 2.7 to 4.3 (free space is 2)
 #endif
 
+// ref: https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/kconfig.html#config-lwip-esp-gratuitous-arp
+// ref: https://github.com/xoseperez/espurna/pull/1877#issuecomment-525612546 
+//
+// Broadcast gratuitous ARP periodically to update ARP tables on the AP and all devices on the same network.
+// Helps to solve compatibility issues when ESP fails to timely reply to ARP requests, causing the device's ARP table entry to expire.
+
+#ifndef WIFI_GRATUITOUS_ARP_SUPPORT
+#define WIFI_GRATUITOUS_ARP_SUPPORT 1
+#endif
+
+// Interval is randomized on each boot in range from ..._MIN to ..._MAX (ms)
+#ifndef WIFI_GRATUITOUS_ARP_INTERVAL_MIN
+#define WIFI_GRATUITOUS_ARP_INTERVAL_MIN 15000
+#endif
+
+#ifndef WIFI_GRATUITOUS_ARP_INTERVAL_MAX
+#define WIFI_GRATUITOUS_ARP_INTERVAL_MAX 30000
+#endif
+
 // -----------------------------------------------------------------------------
 // WEB
 // -----------------------------------------------------------------------------

diff --git a/code/espurna/config/prototypes.h b/code/espurna/config/prototypes.h
@@ -367,6 +367,12 @@ using wifi_callback_f = std::function<void(justwifi_messages_t code, char * para
 void wifiRegister(wifi_callback_f callback);
 bool wifiConnected();
 
+#if LWIP_VERSION_MAJOR == 1
+#include <netif/etharp.h>
+#else // LWIP_VERSION_MAJOR >= 2
+#include <lwip/etharp.h>
+#endif
+
 // -----------------------------------------------------------------------------
 // THERMOSTAT
 // -----------------------------------------------------------------------------

diff --git a/code/espurna/wifi.ino b/code/espurna/wifi.ino
@@ -15,6 +15,11 @@ bool _wifi_smartconfig_running = false;
 bool _wifi_smartconfig_initial = false;
 uint8_t _wifi_ap_mode = WIFI_AP_FALLBACK;
 
+#if WIFI_GRATUITOUS_ARP_SUPPORT
+unsigned long _wifi_gratuitous_arp_interval = 0;
+unsigned long _wifi_gratuitous_arp_last = 0;
+#endif
+
 // -----------------------------------------------------------------------------
 // PRIVATE
 // -----------------------------------------------------------------------------
@@ -91,6 +96,14 @@ void _wifiConfigure() {
  sleep_mode = constrain(sleep_mode, 0, 2);
 
  WiFi.setSleepMode(static_cast<WiFiSleepType_t>(sleep_mode));
+
+ #if WIFI_GRATUITOUS_ARP_SUPPORT
+ _wifi_gratuitous_arp_last = millis();
+ _wifi_gratuitous_arp_interval = getSetting("wifiGarpIntvl", secureRandom(
+ WIFI_GRATUITOUS_ARP_INTERVAL_MIN, WIFI_GRATUITOUS_ARP_INTERVAL_MAX
+ )).toInt();
+ #endif
+
 }
 
 void _wifiScan(uint32_t client_id = 0) {
@@ -504,6 +517,47 @@ void _wifiWebSocketOnAction(uint32_t client_id, const char * action, JsonObject&
 
 #endif
 
+// -----------------------------------------------------------------------------
+// SUPPORT
+// -----------------------------------------------------------------------------
+
+#if WIFI_GRATUITOUS_ARP_SUPPORT
+
+// ref: lwip src/core/netif.c netif_issue_reports(...)
+// ref: esp-lwip/core/ipv4/etharp.c garp_tmr()
+// TODO: only for ipv4, need (?) a different method with ipv6
+bool _wifiSendGratuitousArp() {
+
+ bool result = false;
+ for (netif* interface = netif_list; interface != nullptr; interface = interface->next) {
+ if (
+ (interface->flags & NETIF_FLAG_ETHARP)
+ && (interface->hwaddr_len == ETHARP_HWADDR_LEN)
+ #if LWIP_VERSION_MAJOR == 1
+ && (!ip_addr_isany(&interface->ip_addr))
+ #else
+ && (!ip4_addr_isany_val(*netif_ip4_addr(interface)))
+ #endif
+ && (interface->flags & NETIF_FLAG_LINK_UP)
+ && (interface->flags & NETIF_FLAG_UP)
+ ) {
+ etharp_gratuitous(interface);
+ result = true;
+ }
+ }
+
+ return result;
+}
+
+void _wifiSendGratuitousArp(unsigned long interval) {
+ if (millis() - _wifi_gratuitous_arp_last > interval) {
+ _wifi_gratuitous_arp_last = millis();
+ _wifiSendGratuitousArp();
+ }
+}
+
+#endif // WIFI_GRATUITOUS_ARP_SUPPORT
+
 // -----------------------------------------------------------------------------
 // INFO
 // -----------------------------------------------------------------------------
@@ -730,4 +784,11 @@ void wifiLoop() {
  _wifiCheckAP();
  }
 
+ #if WIFI_GRATUITOUS_ARP_SUPPORT
+ // Only send out gra arp when in STA mode
+ if (_wifi_gratuitous_arp_interval) {
+ _wifiSendGratuitousArp(_wifi_gratuitous_arp_interval);
+ }
+ #endif
+
 }