add code for sending gratuitous ARP periodically

src/core/ipv4/etharp.c

@@ -54,6 +54,7 @@
 #include "lwip/autoip.h"
 #include "lwip/prot/iana.h"
 #include "netif/ethernet.h"
+#include "lwip/netif.h"
 
 #include <string.h>
 
@@ -137,6 +138,21 @@ static err_t etharp_raw(struct netif *netif,
                         const struct eth_addr *hwdst_addr, const ip4_addr_t *ipdst_addr,
                         const u16_t opcode);
 
+#if ESP_GRATUITOUS_ARP
+void garp_tmr(void)
+{
+  struct netif* garp_netif = NULL;
+
+  for (garp_netif = netif_list; garp_netif != NULL; garp_netif = garp_netif->next) {
+    if (netif_is_up(garp_netif) && netif_is_link_up(garp_netif) && !ip4_addr_isany_val(*netif_ip4_addr(garp_netif))) {
+      if ((garp_netif->flags & NETIF_FLAG_ETHARP) && (garp_netif->flags & NETIF_FLAG_GARP)) {
+        etharp_gratuitous(garp_netif);
+      }
+    }
+  }
+}
+#endif
+
 #if ARP_QUEUEING
 /**
  * Free a complete queue of etharp entries

src/core/netif.c

@@ -727,6 +727,17 @@ netif_set_addr(struct netif *netif, const ip4_addr_t *ipaddr, const ip4_addr_t *
 }
 #endif /* LWIP_IPV4*/
 
+
+/**
+ * Set the netif flags for GARP
+ */
+#if ESP_GRATUITOUS_ARP
+void netif_set_garp_flag(struct netif *netif)
+{
+  netif->flags |= NETIF_FLAG_GARP;
+}
+#endif
+
 /**
  * @ingroup netif
  * Remove a network interface from the list of lwIP netifs.

src/core/timeouts.c

@@ -90,6 +90,9 @@ const struct lwip_cyclic_timer lwip_cyclic_timers[] = {
 #endif /* IP_REASSEMBLY */
 #if LWIP_ARP
   {ARP_TMR_INTERVAL, HANDLER(etharp_tmr)},
+#if ESP_GRATUITOUS_ARP
+  {GARP_TMR_INTERVAL, HANDLER(garp_tmr)},
+#endif /* ESP_GRATUITOUS_ARP */
 #endif /* LWIP_ARP */
 #if LWIP_DHCP
   {DHCP_COARSE_TIMER_MSECS, HANDLER(dhcp_coarse_tmr)},

src/include/lwip/etharp.h

@@ -73,6 +73,16 @@ struct etharp_q_entry {
 };
 #endif /* ARP_QUEUEING */
 
+#if ESP_GRATUITOUS_ARP
+#ifdef CONFIG_GARP_TMR_INTERVAL
+#define GARP_TMR_INTERVAL (CONFIG_GARP_TMR_INTERVAL*1000UL)
+#else
+#define GARP_TMR_INTERVAL 60000 
+#endif
+
+void garp_tmr(void);
+#endif
+
 #define etharp_init() /* Compatibility define, no init needed. */
 void etharp_tmr(void);
 ssize_t etharp_find_addr(struct netif *netif, const ip4_addr_t *ipaddr,

src/include/lwip/netif.h

@@ -106,6 +106,11 @@ extern "C" {
  * Set by the netif driver in its init function. */
 #define NETIF_FLAG_MLD6         0x40U
 
+#if ESP_GRATUITOUS_ARP
+/** If set, the netif will send gratuitous ARP periodically */
+#define NETIF_FLAG_GARP         0x80U
+#endif
+
 /**
  * @}
  */
@@ -438,6 +443,11 @@ void netif_set_addr(struct netif *netif, const ip4_addr_t *ipaddr, const ip4_add
 #else /* LWIP_IPV4 */
 struct netif *netif_add(struct netif *netif, void *state, netif_init_fn init, netif_input_fn input);
 #endif /* LWIP_IPV4 */
+
+#if ESP_GRATUITOUS_ARP
+void netif_set_garp_flag(struct netif *netif);
+#endif
+
 void netif_remove(struct netif * netif);
 
 /* Returns a network interface given its name. The name is of the form

src/include/lwip/opt.h

@@ -505,8 +505,9 @@
  * The number of sys timeouts used by the core stack (not apps)
  * The default number of timeouts is calculated here for all enabled modules.
  */
+#if !defined LWIP_NUM_SYS_TIMEOUT_INTERNAL || defined __DOXYGEN__
 #define LWIP_NUM_SYS_TIMEOUT_INTERNAL   (LWIP_TCP + IP_REASSEMBLY + LWIP_ARP + (2*LWIP_DHCP) + LWIP_AUTOIP + LWIP_IGMP + LWIP_DNS + PPP_NUM_TIMEOUTS + (LWIP_IPV6 * (1 + LWIP_IPV6_REASS + LWIP_IPV6_MLD)))
-
+#endif
 /**
  * MEMP_NUM_SYS_TIMEOUT: the number of simultaneously active timeouts.
  * The default number of timeouts is calculated here for all enabled modules.

test/unit/lwipopts.h

@@ -98,5 +98,7 @@
 #define ESP_PPP                                 1
 #define ESP_LWIP_IGMP_TIMERS_ONDEMAND           1
 #define ESP_LWIP_MLD6_TIMERS_ONDEMAND           1
+#define ESP_GRATUITOUS_ARP                      1
+
 
 #endif /* LWIP_HDR_LWIPOPTS_H */