netfilter: xt_addrtype: replace rt6_lookup with nf_afinfo->route

This avoids pulling in the ipv6 module when using (ipv4-only) iptables
-m addrtype.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>

2 files changed, 28 insertions, 15 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index c3f988aa115..32bff6d86cb 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -652,7 +652,6 @@ comment "Xtables matches"
 config NETFILTER_XT_MATCH_ADDRTYPE
         tristate '"addrtype" address type match support'
         depends on NETFILTER_ADVANCED
-        depends on (IPV6 || IPV6=n)
         ---help---
           This option allows you to match what routing thinks of an address,
           eg. UNICAST, LOCAL, BROADCAST, ...
diff --git a/net/netfilter/xt_addrtype.c b/net/netfilter/xt_addrtype.c
index 2220b85e951..b77d383cec7 100644
--- a/net/netfilter/xt_addrtype.c
+++ b/net/netfilter/xt_addrtype.c
@@ -32,11 +32,32 @@ MODULE_ALIAS("ipt_addrtype");
 MODULE_ALIAS("ip6t_addrtype");
 
 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
-static u32 xt_addrtype_rt6_to_type(const struct rt6_info *rt)
+static u32 match_lookup_rt6(struct net *net, const struct net_device *dev,
+                            const struct in6_addr *addr)
 {
+        const struct nf_afinfo *afinfo;
+        struct flowi6 flow;
+        struct rt6_info *rt;
         u32 ret;
+        int route_err;
 
-        if (!rt)
+        memset(&flow, 0, sizeof(flow));
+        ipv6_addr_copy(&flow.daddr, addr);
+        if (dev)
+                flow.flowi6_oif = dev->ifindex;
+
+        rcu_read_lock();
+
+        afinfo = nf_get_afinfo(NFPROTO_IPV6);
+        if (afinfo != NULL)
+                route_err = afinfo->route(net, (struct dst_entry **)&rt,
+                                        flowi6_to_flowi(&flow), !!dev);
+        else
+                route_err = 1;
+
+        rcu_read_unlock();
+
+        if (route_err)
                 return XT_ADDRTYPE_UNREACHABLE;
 
         if (rt->rt6i_flags & RTF_REJECT)
@@ -48,6 +69,9 @@ static u32 xt_addrtype_rt6_to_type(const struct rt6_info *rt)
                 ret |= XT_ADDRTYPE_LOCAL;
         if (rt->rt6i_flags & RTF_ANYCAST)
                 ret |= XT_ADDRTYPE_ANYCAST;
+
+
+        dst_release(&rt->dst);
         return ret;
 }
 
@@ -65,18 +89,8 @@ static bool match_type6(struct net *net, const struct net_device *dev,
                 return false;
 
         if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST |
-             XT_ADDRTYPE_UNREACHABLE) & mask) {
-                struct rt6_info *rt;
-                u32 type;
-                int ifindex = dev ? dev->ifindex : 0;
-
-                rt = rt6_lookup(net, addr, NULL, ifindex, !!dev);
-
-                type = xt_addrtype_rt6_to_type(rt);
-
-                dst_release(&rt->dst);
-                return !!(mask & type);
-        }
+             XT_ADDRTYPE_UNREACHABLE) & mask)
+                return !!(mask & match_lookup_rt6(net, dev, addr));
         return true;
 }