netifapi: add thread safe ARP APIs (task #14724)

This adds thread safe netifapi ARP cache APIs for add/remove

CHANGELOG

@@ -6,6 +6,9 @@ HISTORY
 
   ++ New features:
 
+  2017-11-14: Joel Cunningham
+  * netifapi: Add thread safe ARP cache APIs (task #14724)
+
   2017-11-06: Axel Lin
   * TCP: kill existing connections with a LOWER priority than the one currently being opened.
     Previous implementations also kill existing connections of the SAME priority.

src/api/netifapi.c

@@ -42,6 +42,7 @@
 
 #if LWIP_NETIF_API /* don't build if not configured for use in lwipopts.h */
 
+#include "lwip/etharp.h"
 #include "lwip/netifapi.h"
 #include "lwip/memp.h"
 #include "lwip/priv/tcpip_priv.h"
@@ -147,6 +148,69 @@ netifapi_do_netif_common(struct tcpip_api_call_data *m)
   }
 }
 
+#if LWIP_ARP && LWIP_IPV4
+/**
+ * @ingroup netifapi_arp
+ * Add or update an entry in the ARP cache.
+ * For an update, ipaddr is used to find the cache entry.
+ *
+ * @param ipaddr IPv4 address of cache entry
+ * @param ethaddr hardware address mapped to ipaddr
+ * @param type type of ARP cache entry
+ * @return ERR_OK: entry added/updated, else error from err_t
+ */
+err_t
+netifapi_arp_add(const ip4_addr_t *ipaddr, struct eth_addr *ethaddr, enum netifapi_arp_entry type)
+{
+  err_t err;
+
+  /* We only support permanent entries currently */
+  LWIP_UNUSED_ARG(type);
+
+#if ETHARP_SUPPORT_STATIC_ENTRIES && LWIP_TCPIP_CORE_LOCKING
+  LOCK_TCPIP_CORE();
+  err = etharp_add_static_entry(ipaddr, ethaddr);
+  UNLOCK_TCPIP_CORE();
+#else
+  /* @todo add new vars to struct netifapi_msg and create a 'do' func */
+  LWIP_UNUSED_ARG(ipaddr);
+  LWIP_UNUSED_ARG(ethaddr);
+  err = ERR_VAL;
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES && LWIP_TCPIP_CORE_LOCKING */
+
+  return err;
+}
+
+/**
+ * @ingroup netifapi_arp
+ * Remove an entry in the ARP cache identified by ipaddr
+ *
+ * @param ipaddr IPv4 address of cache entry
+ * @param type type of ARP cache entry
+ * @return ERR_OK: entry removed, else error from err_t
+ */
+err_t
+netifapi_arp_remove(const ip4_addr_t *ipaddr, enum netifapi_arp_entry type)
+{
+  err_t err;
+
+  /* We only support permanent entries currently */
+  LWIP_UNUSED_ARG(type);
+
+#if ETHARP_SUPPORT_STATIC_ENTRIES && LWIP_TCPIP_CORE_LOCKING
+  LOCK_TCPIP_CORE();
+  err = etharp_remove_static_entry(ipaddr);
+  UNLOCK_TCPIP_CORE();
+#else
+  /* @todo add new vars to struct netifapi_msg and create a 'do' func */
+  LWIP_UNUSED_ARG(ipaddr);
+  err = ERR_VAL;
+#endif /* ETHARP_SUPPORT_STATIC_ENTRIES && LWIP_TCPIP_CORE_LOCKING */
+
+  return err;
+}
+#endif /* LWIP_ARP && LWIP_IPV4 */
+
 /**
  * @ingroup netifapi_netif
  * Call netif_add() in a thread-safe way by running that function inside the

src/include/lwip/netifapi.h

@@ -42,12 +42,26 @@
 #include "lwip/autoip.h"
 #include "lwip/priv/tcpip_priv.h"
 #include "lwip/priv/api_msg.h"
+#include "lwip/prot/ethernet.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /* API for application */
+#if LWIP_ARP && LWIP_IPV4
+/* Used for netfiapi_arp_* APIs */
+enum netifapi_arp_entry {
+  NETIFAPI_ARP_PERM /* Permanent entry */
+  /* Other entry types can be added here */
+};
+
+/** @ingroup netifapi_arp */
+err_t netifapi_arp_add(const ip4_addr_t *ipaddr, struct eth_addr *ethaddr, enum netifapi_arp_entry type);
+/** @ingroup netifapi_arp */
+err_t netifapi_arp_remove(const ip4_addr_t *ipaddr, enum netifapi_arp_entry type);
+#endif /* LWIP_ARP && LWIP_IPV4 */
+
 err_t netifapi_netif_add(struct netif *netif,
 #if LWIP_IPV4
                          const ip4_addr_t *ipaddr, const ip4_addr_t *netmask, const ip4_addr_t *gw,