[NETFILTER]: Prepare {ipt,ip6t}_policy match for x_tables unification

The IPv4 and IPv6 version of the policy match are identical besides address
comparison and the data structure used for userspace communication. Unify
the data structures to break compatiblity now (before it is released), so
we can port it to x_tables in 2.6.17.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter_ipv4/ipt_policy.h

@@ -27,12 +27,18 @@ struct ipt_policy_spec
 			reqid:1;
 };
 
+union ipt_policy_addr
+{
+	struct in_addr	a4;
+	struct in6_addr	a6;
+};
+
 struct ipt_policy_elem
 {
-	u_int32_t	saddr;
-	u_int32_t	smask;
-	u_int32_t	daddr;
-	u_int32_t	dmask;
+	union ipt_policy_addr	saddr;
+	union ipt_policy_addr	smask;
+	union ipt_policy_addr	daddr;
+	union ipt_policy_addr	dmask;
 	u_int32_t		spi;
 	u_int32_t		reqid;
 	u_int8_t		proto;

include/linux/netfilter_ipv6/ip6t_policy.h

@@ -27,12 +27,18 @@ struct ip6t_policy_spec
 			reqid:1;
 };
 
+union ip6t_policy_addr
+{
+	struct in_addr	a4;
+	struct in6_addr	a6;
+};
+
 struct ip6t_policy_elem
 {
-	struct in6_addr	saddr;
-	struct in6_addr	smask;
-	struct in6_addr	daddr;
-	struct in6_addr	dmask;
+	union ip6t_policy_addr	saddr;
+	union ip6t_policy_addr	smask;
+	union ip6t_policy_addr	daddr;
+	union ip6t_policy_addr	dmask;
 	u_int32_t		spi;
 	u_int32_t		reqid;
 	u_int8_t		proto;

net/ipv4/netfilter/ipt_policy.c

@@ -26,10 +26,13 @@ MODULE_LICENSE("GPL");
 static inline int
 match_xfrm_state(struct xfrm_state *x, const struct ipt_policy_elem *e)
 {
+#define MATCH_ADDR(x,y,z)	(!e->match.x ||				     \
+		                 ((e->x.a4.s_addr == (e->y.a4.s_addr & (z))) \
+				  ^ e->invert.x))
 #define MATCH(x,y)		(!e->match.x || ((e->x == (y)) ^ e->invert.x))
 
-	return MATCH(saddr, x->props.saddr.a4 & e->smask) &&
-	       MATCH(daddr, x->id.daddr.a4 & e->dmask) &&
+	return MATCH_ADDR(saddr, smask, x->props.saddr.a4) &&
+	       MATCH_ADDR(daddr, dmask, x->id.daddr.a4) &&
 	       MATCH(proto, x->id.proto) &&
 	       MATCH(mode, x->props.mode) &&
 	       MATCH(spi, x->id.spi) &&

net/ipv6/netfilter/ip6t_policy.c

@@ -27,7 +27,7 @@ static inline int
 match_xfrm_state(struct xfrm_state *x, const struct ip6t_policy_elem *e)
 {
 #define MATCH_ADDR(x,y,z)	(!e->match.x ||				       \
-				 ((!ip6_masked_addrcmp(&e->x, &e->y, z)) \
+				 ((!ip6_masked_addrcmp(&e->x.a6, &e->y.a6, z)) \
 				  ^ e->invert.x))
 #define MATCH(x,y)		(!e->match.x || ((e->x == (y)) ^ e->invert.x))