X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=net%2Fbridge%2Fnetfilter%2Febt_arp.c;h=7c535be75665ce8dd32c23818c866ed972601976;hb=62429f434091586d54b37b8dd46076e7c08b27b9;hp=9c599800a90005b2a4602d6782daf86fb7b576ce;hpb=7e23772f414cdbfb2a08aed237d6e926bb1cb728;p=linux-2.6

diff --git a/net/bridge/netfilter/ebt_arp.c b/net/bridge/netfilter/ebt_arp.c
index 9c599800a9..7c535be756 100644
--- a/net/bridge/netfilter/ebt_arp.c
+++ b/net/bridge/netfilter/ebt_arp.c
@@ -18,8 +18,9 @@
 static int ebt_filter_arp(const struct sk_buff *skb, const struct net_device *in,
    const struct net_device *out, const void *data, unsigned int datalen)
 {
-	struct ebt_arp_info *info = (struct ebt_arp_info *)data;
-	struct arphdr _arph, *ah;
+	const struct ebt_arp_info *info = data;
+	const struct arphdr *ah;
+	struct arphdr _arph;
 
 	ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 	if (ah == NULL)
@@ -34,41 +35,39 @@ static int ebt_filter_arp(const struct sk_buff *skb, const struct net_device *in
 	   ah->ar_pro, EBT_ARP_PTYPE))
 		return EBT_NOMATCH;
 
-	if (info->bitmask & (EBT_ARP_SRC_IP | EBT_ARP_DST_IP)) {
-		__be32 _addr, *ap;
+	if (info->bitmask & (EBT_ARP_SRC_IP | EBT_ARP_DST_IP | EBT_ARP_GRAT)) {
+		const __be32 *sap, *dap;
+		__be32 saddr, daddr;
 
-		/* IPv4 addresses are always 4 bytes */
-		if (ah->ar_pln != sizeof(__be32))
+		if (ah->ar_pln != sizeof(__be32) || ah->ar_pro != htons(ETH_P_IP))
+			return EBT_NOMATCH;
+		sap = skb_header_pointer(skb, sizeof(struct arphdr) +
+					ah->ar_hln, sizeof(saddr),
+					&saddr);
+		if (sap == NULL)
+			return EBT_NOMATCH;
+		dap = skb_header_pointer(skb, sizeof(struct arphdr) +
+					2*ah->ar_hln+sizeof(saddr),
+					sizeof(daddr), &daddr);
+		if (dap == NULL)
+			return EBT_NOMATCH;
+		if (info->bitmask & EBT_ARP_SRC_IP &&
+		    FWINV(info->saddr != (*sap & info->smsk), EBT_ARP_SRC_IP))
+			return EBT_NOMATCH;
+		if (info->bitmask & EBT_ARP_DST_IP &&
+		    FWINV(info->daddr != (*dap & info->dmsk), EBT_ARP_DST_IP))
+			return EBT_NOMATCH;
+		if (info->bitmask & EBT_ARP_GRAT &&
+		    FWINV(*dap != *sap, EBT_ARP_GRAT))
 			return EBT_NOMATCH;
-		if (info->bitmask & EBT_ARP_SRC_IP) {
-			ap = skb_header_pointer(skb, sizeof(struct arphdr) +
-						ah->ar_hln, sizeof(_addr),
-						&_addr);
-			if (ap == NULL)
-				return EBT_NOMATCH;
-			if (FWINV(info->saddr != (*ap & info->smsk),
-			   EBT_ARP_SRC_IP))
-				return EBT_NOMATCH;
-		}
-
-		if (info->bitmask & EBT_ARP_DST_IP) {
-			ap = skb_header_pointer(skb, sizeof(struct arphdr) +
-						2*ah->ar_hln+sizeof(__be32),
-						sizeof(_addr), &_addr);
-			if (ap == NULL)
-				return EBT_NOMATCH;
-			if (FWINV(info->daddr != (*ap & info->dmsk),
-			   EBT_ARP_DST_IP))
-				return EBT_NOMATCH;
-		}
 	}
 
 	if (info->bitmask & (EBT_ARP_SRC_MAC | EBT_ARP_DST_MAC)) {
-		unsigned char _mac[ETH_ALEN], *mp;
+		const unsigned char *mp;
+		unsigned char _mac[ETH_ALEN];
 		uint8_t verdict, i;
 
-		/* MAC addresses are 6 bytes */
-		if (ah->ar_hln != ETH_ALEN)
+		if (ah->ar_hln != ETH_ALEN || ah->ar_hrd != htons(ARPHRD_ETHER))
 			return EBT_NOMATCH;
 		if (info->bitmask & EBT_ARP_SRC_MAC) {
 			mp = skb_header_pointer(skb, sizeof(struct arphdr),
@@ -104,7 +103,7 @@ static int ebt_filter_arp(const struct sk_buff *skb, const struct net_device *in
 static int ebt_arp_check(const char *tablename, unsigned int hookmask,
    const struct ebt_entry *e, void *data, unsigned int datalen)
 {
-	struct ebt_arp_info *info = (struct ebt_arp_info *)data;
+	const struct ebt_arp_info *info = data;
 
 	if (datalen != EBT_ALIGN(sizeof(struct ebt_arp_info)))
 		return -EINVAL;
@@ -117,8 +116,7 @@ static int ebt_arp_check(const char *tablename, unsigned int hookmask,
 	return 0;
 }
 
-static struct ebt_match filter_arp =
-{
+static struct ebt_match filter_arp __read_mostly = {
 	.name		= EBT_ARP_MATCH,
 	.match		= ebt_filter_arp,
 	.check		= ebt_arp_check,
@@ -137,4 +135,5 @@ static void __exit ebt_arp_fini(void)
 
 module_init(ebt_arp_init);
 module_exit(ebt_arp_fini);
+MODULE_DESCRIPTION("Ebtables: ARP protocol packet match");
 MODULE_LICENSE("GPL");