From 4c9fe60693c9e30af30987115f84007d9dca4e51 Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon>
Date: Sun, 14 Feb 2010 18:08:16 +0000
Subject: [PATCH] Fixed ARP input processing: only add a new entry if a request
 was directed as us (RFC 826, Packet Reception), otherwise only update
 existing entries; internalized some functions

---
 CHANGELOG                  |  5 +++++
 src/include/netif/etharp.h |  3 ---
 src/netif/etharp.c         | 21 +++++++++++----------
 3 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index e09ad3ba..1ba0154c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -131,6 +131,11 @@ HISTORY
 
   ++ Bugfixes:
 
+  2010-02-14: Simon Goldschmidt
+  * etharp.c/.h: Fixed ARP input processing: only add a new entry if a
+    request was directed as us (RFC 826, Packet Reception), otherwise
+    only update existing entries; internalized some functions
+
   2010-02-14: Simon Goldschmidt
   * netif.h, etharp.c, tcpip.c: Fixed bug #28183 (ARP and TCP/IP cannot be
     disabled on netif used for PPPoE) by adding a new netif flag
diff --git a/src/include/netif/etharp.h b/src/include/netif/etharp.h
index 63b66d7a..3eb0604f 100644
--- a/src/include/netif/etharp.h
+++ b/src/include/netif/etharp.h
@@ -163,9 +163,6 @@ struct etharp_q_entry {
 void etharp_tmr(void);
 s8_t etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr,
          struct eth_addr **eth_ret, ip_addr_t **ip_ret);
-void etharp_ip_input(struct netif *netif, struct pbuf *p);
-void etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr,
-         struct pbuf *p);
 err_t etharp_output(struct netif *netif, struct pbuf *q, ip_addr_t *ipaddr);
 err_t etharp_query(struct netif *netif, ip_addr_t *ipaddr, struct pbuf *q);
 err_t etharp_request(struct netif *netif, ip_addr_t *ipaddr);
diff --git a/src/netif/etharp.c b/src/netif/etharp.c
index 79872f56..d64bafc4 100644
--- a/src/netif/etharp.c
+++ b/src/netif/etharp.c
@@ -344,10 +344,10 @@ find_entry(ip_addr_t *ipaddr, u8_t flags)
   }
   /* { we have no match } => try to create a new entry */
    
-  /* no empty entry found and not allowed to recycle? */
-  if (((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_TRY_HARD) == 0))
-      /* or don't create new entry, only search? */
-      || ((flags & ETHARP_FIND_ONLY) != 0)) {
+  /* don't create new entry, only search? */
+  if (((flags & ETHARP_FIND_ONLY) != 0) ||
+      /* or no empty entry found and not allowed to recycle? */
+      ((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_TRY_HARD) == 0))) {
     LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty entry found and not allowed to recycle\n"));
     return (s8_t)ERR_MEM;
   }
@@ -565,6 +565,7 @@ etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr,
   return -1;
 }
 
+#if ETHARP_TRUST_IP_MAC
 /**
  * Updates the ARP table using the given IP packet.
  *
@@ -580,7 +581,7 @@ etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr,
  *
  * @see pbuf_free()
  */
-void
+static void
 etharp_ip_input(struct netif *netif, struct pbuf *p)
 {
   struct eth_hdr *ethhdr;
@@ -604,12 +605,12 @@ etharp_ip_input(struct netif *netif, struct pbuf *p)
   }
 
   LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table.\n"));
-  /* update ARP table */
+  /* update the source IP address in the cache, if present */
   /* @todo We could use ETHARP_TRY_HARD if we think we are going to talk
    * back soon (for example, if the destination IP address is ours. */
-  update_arp_entry(netif, &(iphdr->src), &(ethhdr->src), 0);
+  update_arp_entry(netif, &(iphdr->src), &(ethhdr->src), ETHARP_FIND_ONLY);
 }
-
+#endif /* ETHARP_TRUST_IP_MAC */
 
 /**
  * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache  
@@ -626,7 +627,7 @@ etharp_ip_input(struct netif *netif, struct pbuf *p)
  *
  * @see pbuf_free()
  */
-void
+static void
 etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
 {
   struct etharp_hdr *hdr;
@@ -704,7 +705,7 @@ etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
   /* ARP message not directed to us? */
   } else {
     /* update the source IP address in the cache, if present */
-    update_arp_entry(netif, &sipaddr, &(hdr->shwaddr), 0);
+    update_arp_entry(netif, &sipaddr, &(hdr->shwaddr), ETHARP_FIND_ONLY);
   }
 
   /* now act on the message itself */