[patch] Reject ARP from our hardware address

dhcpcd-arp.patch (text/plain), 981 bytes, created by Roy Marples (RETIRED) on 2007-07-25 21:36:26 UTC

Index: arp.c
===================================================================
--- arp.c	(revision 253)
+++ arp.c	(working copy)
@@ -190,17 +190,24 @@
 				continue;
 			if (reply->ar_pln != sizeof (struct in_addr))
 				continue;
-
-			if (reply->ar_hln != ETHER_ADDR_LEN)
-				continue;
 			if ((unsigned) bytes < sizeof (reply) + 
 				2 * (4 + reply->ar_hln))
 				continue;
 
+			/* Ensure the ARP reply is for the address we asked for */
+			if (rp.a->s_addr != address.s_addr)
+				continue;
+
+			/* Some systems send a reply back from our hwaddress - weird */
+			if (reply->ar_hln == iface->hwlen &&
+				memcmp (rh.c, iface->hwaddr, iface->hwlen) == 0)
+				continue;
+
 			rp.c = (unsigned char *) ar_spa (reply);
 			rh.c = (unsigned char *) ar_sha (reply);
 			logger (LOG_ERR, "ARPOP_REPLY received from %s (%s)",
-					inet_ntoa (*rp.a), ether_ntoa (rh.a));
+					inet_ntoa (*rp.a),
+					hwaddr_ntoa (rh.c, reply->ar_hln));
 			retval = -1;
 			goto eexit;
 		}