PATCH: send-to-self: smaller & better

@@ -114,6 +114,16 @@
 #define SIOCBONDINFOQUERY      0x8994	/* rtn info about bond state    */
 #define SIOCBONDCHANGEACTIVE   0x8995   /* update to a new active slave */
 			
+
+/* Ben's little hack land */
+#define SIOCSACCEPTLOCALADDRS  0x89a0   /*  Allow interfaces to accept pkts from
+                                         * local interfaces...use with SO_BINDTODEVICE
+                                         */
+#define SIOCGACCEPTLOCALADDRS  0x89a1   /*  Allow interfaces to accept pkts from
+                                         * local interfaces...use with SO_BINDTODEVICE
+                                         */
+
+
 /* Device private ioctl calls */
 
 /*

@@ -1,4 +1,4 @@
-/* linux/net/inet/arp.c
+/* linux/net/inet/arp.c  -*-linux-c-*-
  *
  * Version:	$Id: arp.c,v 1.99 2001/08/30 22:55:42 davem Exp $
  *

@@ -351,12 +351,22 @@
 	int flag = 0;
 	/*unsigned long now; */
 
-	if (ip_route_output(&rt, sip, tip, 0, 0) < 0)
+	if (ip_route_output(&rt, sip, tip, 0, 0) < 0)
 		return 1;
-	if (rt->u.dst.dev != dev) {
-		NET_INC_STATS_BH(ArpFilter);
-		flag = 1;
-	}
+
+	if (rt->u.dst.dev != dev) {
+                if ((dev->priv_flags & IFF_ACCEPT_LOCAL_ADDRS) &&
+                    (rt->u.dst.dev == &loopback_dev))  {
+                        /* OK, we'll let this special case slide, so that we can arp from one
+                         * local interface to another.  This seems to work, but could use some
+                         * review. --Ben
+                         */
+                }
+                else {
+                        NET_INC_STATS_BH(ArpFilter);
+                        flag = 1;
+                }
+        }
 	ip_rt_put(rt);
 	return flag;
 }

@@ -233,8 +233,17 @@
 
 	if (fib_lookup(&key, &res))
 		goto last_resort;
-	if (res.type != RTN_UNICAST)
-		goto e_inval_res;
+
+	if (res.type != RTN_UNICAST) {
+                if ((res.type == RTN_LOCAL) &&
+                    (dev->priv_flags & IFF_ACCEPT_LOCAL_ADDRS)) {
+                        /* All is OK */
+                }
+                else {
+                        goto e_inval_res;
+                }
+        }
+
 	*spec_dst = FIB_RES_PREFSRC(res);
 	fib_combine_itag(itag, &res);
 #ifdef CONFIG_IP_ROUTE_MULTIPATH

@@ -1394,7 +1394,7 @@
 #define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
 #endif
 
-	/* Never answer to SYNs send to broadcast or multicast */
+	/* Never answer to SYNs sent to broadcast or multicast */
 	if (((struct rtable *)skb->dst)->rt_flags &
 	    (RTCF_BROADCAST|RTCF_MULTICAST))
 		goto drop;

@@ -2153,6 +2183,24 @@
 			notifier_call_chain(&netdev_chain, NETDEV_CHANGENAME, dev);
 			return 0;
 
+                case SIOCSACCEPTLOCALADDRS:
+                        if (ifr->ifr_flags) {
+                                dev->priv_flags |= IFF_ACCEPT_LOCAL_ADDRS;
+                        }
+                        else {
+                                dev->priv_flags &= ~IFF_ACCEPT_LOCAL_ADDRS;
+                        }
+                        return 0;
+
+                case SIOCGACCEPTLOCALADDRS:
+                        if (dev->priv_flags & IFF_ACCEPT_LOCAL_ADDRS) {
+                                ifr->ifr_flags = 1;
+                        }
+                        else {
+                                ifr->ifr_flags = 0;
+                        }
+                        return 0;
+
 		/*
 		 *	Unknown or private ioctl
 		 */

@@ -2249,6 +2297,7 @@
 		case SIOCGIFMAP:
 		case SIOCGIFINDEX:
 		case SIOCGIFTXQLEN:
+                case SIOCGACCEPTLOCALADDRS:
 			dev_load(ifr.ifr_name);
 			read_lock(&dev_base_lock);
 			ret = dev_ifsioc(&ifr, cmd);

@@ -2312,6 +2361,7 @@
 		case SIOCBONDSLAVEINFOQUERY:
 		case SIOCBONDINFOQUERY:
 		case SIOCBONDCHANGEACTIVE:
+                case SIOCSACCEPTLOCALADDRS:
 			if (!capable(CAP_NET_ADMIN))
 				return -EPERM;
 			dev_load(ifr.ifr_name);