From d656e9f28e8eaf988042d7430bd631e4dbe9fbff Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon>
Date: Mon, 10 May 2010 14:10:46 +0000
Subject: [PATCH] Added option LWIP_ARP_FILTER_NETIF to use multiple IPs on one
 hardware interface (by using multiple netifs, each with its own IP)

---
 src/include/netif/etharp.h | 10 ++++++++++
 src/netif/etharp.c         |  4 ++++
 2 files changed, 14 insertions(+)

diff --git a/src/include/netif/etharp.h b/src/include/netif/etharp.h
index af78f525..51d7b6ad 100644
--- a/src/include/netif/etharp.h
+++ b/src/include/netif/etharp.h
@@ -157,6 +157,16 @@ PACK_STRUCT_END
 #define ARP_REQUEST 1
 #define ARP_REPLY   2
 
+/** Define this to 1 and define LWIP_ARP_FILTER_NETIF_FN(pbuf, netif, type)
+ * to a filter function that returns the correct netif when using multiple
+ * netifs on one hardware interface where the netif's low-level receive
+ * routine cannot decide for the correct netif (e.g. when mapping multiple
+ * IP addresses to one hardware interface).
+ */
+#ifndef LWIP_ARP_FILTER_NETIF
+#define LWIP_ARP_FILTER_NETIF 0
+#endif
+
 #if ARP_QUEUEING
 /** struct for queueing outgoing packets for unknown address
   * defined here to be accessed by memp.h
diff --git a/src/netif/etharp.c b/src/netif/etharp.c
index fed920c6..42bce4b4 100644
--- a/src/netif/etharp.c
+++ b/src/netif/etharp.c
@@ -1226,6 +1226,10 @@ ethernet_input(struct pbuf *p, struct netif *netif)
   }
 #endif /* ETHARP_SUPPORT_VLAN */
 
+#if LWIP_ARP_FILTER_NETIF
+  netif = LWIP_ARP_FILTER_NETIF_FN(p, netif, type);
+#endif /* LWIP_ARP_FILTER_NETIF*/
+
   switch (type) {
 #if LWIP_ARP
     /* IP packet? */