[NETFILTER]: nf_ct_h323: remove ipv6 module dependency

nf_conntrack_h323 needs ip6_route_output for the call forwarding filter.
Add a ->route function to nf_afinfo and use that to avoid pulling in the
ipv6 module.

Fix the #ifdef for the IPv6 code while I'm at it - the IPv6 support is
only needed when IPv6 conntrack is enabled.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/netfilter.h

@@ -298,10 +298,12 @@ extern void nf_invalidate_cache(int pf);
    Returns true or false. */
 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
 
+struct flowi;
 struct nf_afinfo {
 	unsigned short	family;
 	__sum16		(*checksum)(struct sk_buff *skb, unsigned int hook,
 				    unsigned int dataoff, u_int8_t protocol);
+	int		(*route)(struct dst_entry **dst, struct flowi *fl);
 	void		(*saveroute)(const struct sk_buff *skb,
 				     struct nf_info *info);
 	int		(*reroute)(struct sk_buff *skb,

net/ipv4/netfilter.c

@@ -182,9 +182,15 @@ __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
 
 EXPORT_SYMBOL(nf_ip_checksum);
 
+static int nf_ip_route(struct dst_entry **dst, struct flowi *fl)
+{
+	return ip_route_output_key((struct rtable **)dst, fl);
+}
+
 static struct nf_afinfo nf_ip_afinfo = {
 	.family		= AF_INET,
 	.checksum	= nf_ip_checksum,
+	.route		= nf_ip_route,
 	.saveroute	= nf_ip_saveroute,
 	.reroute	= nf_ip_reroute,
 	.route_key_size	= sizeof(struct ip_rt_info),

net/ipv6/netfilter.c

@@ -81,6 +81,12 @@ static int nf_ip6_reroute(struct sk_buff *skb, const struct nf_info *info)
 	return 0;
 }
 
+static int nf_ip6_route(struct dst_entry **dst, struct flowi *fl)
+{
+	*dst = ip6_route_output(NULL, fl);
+	return (*dst)->error;
+}
+
 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
 			     unsigned int dataoff, u_int8_t protocol)
 {
@@ -118,6 +124,7 @@ EXPORT_SYMBOL(nf_ip6_checksum);
 static struct nf_afinfo nf_ip6_afinfo = {
 	.family		= AF_INET6,
 	.checksum	= nf_ip6_checksum,
+	.route		= nf_ip6_route,
 	.saveroute	= nf_ip6_saveroute,
 	.reroute	= nf_ip6_reroute,
 	.route_key_size	= sizeof(struct ip6_rt_info),

net/netfilter/nf_conntrack_h323_main.c

@@ -708,9 +708,15 @@ static int callforward_do_filter(union nf_conntrack_address *src,
 				 union nf_conntrack_address *dst,
 				 int family)
 {
+	struct nf_afinfo *afinfo;
 	struct flowi fl1, fl2;
 	int ret = 0;
 
+	/* rcu_read_lock()ed by nf_hook_slow() */
+	afinfo = nf_get_afinfo(family);
+	if (!afinfo)
+		return 0;
+
 	memset(&fl1, 0, sizeof(fl1));
 	memset(&fl2, 0, sizeof(fl2));
 
@@ -720,8 +726,8 @@ static int callforward_do_filter(union nf_conntrack_address *src,
 
 		fl1.fl4_dst = src->ip;
 		fl2.fl4_dst = dst->ip;
-		if (ip_route_output_key(&rt1, &fl1) == 0) {
-			if (ip_route_output_key(&rt2, &fl2) == 0) {
+		if (!afinfo->route((struct dst_entry **)&rt1, &fl1)) {
+			if (!afinfo->route((struct dst_entry **)&rt2, &fl2)) {
 				if (rt1->rt_gateway == rt2->rt_gateway &&
 				    rt1->u.dst.dev  == rt2->u.dst.dev)
 					ret = 1;
@@ -731,16 +737,15 @@ static int callforward_do_filter(union nf_conntrack_address *src,
 		}
 		break;
 	}
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+#if defined(CONFIG_NF_CONNTRACK_IPV6) || \
+    defined(CONFIG_NF_CONNTRACK_IPV6_MODULE)
 	case AF_INET6: {
 		struct rt6_info *rt1, *rt2;
 
 		memcpy(&fl1.fl6_dst, src, sizeof(fl1.fl6_dst));
 		memcpy(&fl2.fl6_dst, dst, sizeof(fl2.fl6_dst));
-		rt1 = (struct rt6_info *)ip6_route_output(NULL, &fl1);
-		if (rt1) {
-			rt2 = (struct rt6_info *)ip6_route_output(NULL, &fl2);
-			if (rt2) {
+		if (!afinfo->route((struct dst_entry **)&rt1, &fl1)) {
+			if (!afinfo->route((struct dst_entry **)&rt2, &fl2)) {
 				if (!memcmp(&rt1->rt6i_gateway, &rt2->rt6i_gateway,
 					    sizeof(rt1->rt6i_gateway)) &&
 				    rt1->u.dst.dev == rt2->u.dst.dev)