1 files changed, 46 insertions, 8 deletions

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 0937b34c27ca..8b52179ddc6e 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -539,7 +539,7 @@ struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
 
 	skb_reserve(skb, hlen);
 	skb_reset_network_header(skb);
-	arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
+	arp = skb_put(skb, arp_hdr_len(dev));
 	skb->dev = dev;
 	skb->protocol = htons(ETH_P_ARP);
 	if (!src_hw)
@@ -641,6 +641,32 @@ void arp_xmit(struct sk_buff *skb)
 }
 EXPORT_SYMBOL(arp_xmit);
 
+static bool arp_is_garp(struct net *net, struct net_device *dev,
+			int *addr_type, __be16 ar_op,
+			__be32 sip, __be32 tip,
+			unsigned char *sha, unsigned char *tha)
+{
+	bool is_garp = tip == sip;
+
+	/* Gratuitous ARP _replies_ also require target hwaddr to be
+	 * the same as source.
+	 */
+	if (is_garp && ar_op == htons(ARPOP_REPLY))
+		is_garp =
+			/* IPv4 over IEEE 1394 doesn't provide target
+			 * hardware address field in its ARP payload.
+			 */
+			tha &&
+			!memcmp(tha, sha, dev->addr_len);
+
+	if (is_garp) {
+		*addr_type = inet_addr_type_dev_table(net, dev, sip);
+		if (*addr_type != RTN_UNICAST)
+			is_garp = false;
+	}
+	return is_garp;
+}
+
 /*
  *	Process an arp request.
  */
@@ -653,6 +679,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
 	unsigned char *arp_ptr;
 	struct rtable *rt;
 	unsigned char *sha;
+	unsigned char *tha = NULL;
 	__be32 sip, tip;
 	u16 dev_type = dev->type;
 	int addr_type;
@@ -724,6 +751,7 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
 		break;
 #endif
 	default:
+		tha = arp_ptr;
 		arp_ptr += dev->addr_len;
 	}
 	memcpy(&tip, arp_ptr, 4);
@@ -835,19 +863,25 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
 
 	n = __neigh_lookup(&arp_tbl, &sip, dev, 0);
 
-	if (IN_DEV_ARP_ACCEPT(in_dev)) {
-		unsigned int addr_type = inet_addr_type_dev_table(net, dev, sip);
+	addr_type = -1;
+	if (n || IN_DEV_ARP_ACCEPT(in_dev)) {
+		is_garp = arp_is_garp(net, dev, &addr_type, arp->ar_op,
+				      sip, tip, sha, tha);
+	}
 
+	if (IN_DEV_ARP_ACCEPT(in_dev)) {
 		/* Unsolicited ARP is not accepted by default.
 		   It is possible, that this option should be enabled for some
 		   devices (strip is candidate)
 		 */
-		is_garp = arp->ar_op == htons(ARPOP_REQUEST) && tip == sip &&
-			  addr_type == RTN_UNICAST;
-
 		if (!n &&
-		    ((arp->ar_op == htons(ARPOP_REPLY)  &&
-				addr_type == RTN_UNICAST) || is_garp))
+		    (is_garp ||
+		     (arp->ar_op == htons(ARPOP_REPLY) &&
+		      (addr_type == RTN_UNICAST ||
+		       (addr_type < 0 &&
+			/* postpone calculation to as late as possible */
+			inet_addr_type_dev_table(net, dev, sip) ==
+				RTN_UNICAST)))))
 			n = __neigh_lookup(&arp_tbl, &sip, dev, 1);
 	}
 
@@ -1079,13 +1113,17 @@ static int arp_invalidate(struct net_device *dev, __be32 ip)
 {
 	struct neighbour *neigh = neigh_lookup(&arp_tbl, &ip, dev);
 	int err = -ENXIO;
+	struct neigh_table *tbl = &arp_tbl;
 
 	if (neigh) {
 		if (neigh->nud_state & ~NUD_NOARP)
 			err = neigh_update(neigh, NULL, NUD_FAILED,
 					   NEIGH_UPDATE_F_OVERRIDE|
 					   NEIGH_UPDATE_F_ADMIN, 0);
+		write_lock_bh(&tbl->lock);
 		neigh_release(neigh);
+		neigh_remove_one(neigh, tbl);
+		write_unlock_bh(&tbl->lock);
 	}
 
 	return err;