net: split rt_genid for ipv4 and ipv6

Current net name space has only one genid for both IPv4 and IPv6, it has below
drawbacks:

- Add/delete an IPv4 address will invalidate all IPv6 routing table entries.
- Insert/remove XFRM policy will also invalidate both IPv4/IPv6 routing table
  entries even when the policy is only applied for one address family.

Thus, this patch attempt to split one genid for two to cater for IPv4 and IPv6
separately in a fine granularity.

Signed-off-by: Fan Du <fan.du@windriver.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 3 insertions, 2 deletions

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index a5ac969aeefe..0d1a9b153fbb 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -766,6 +766,7 @@ static int __net_init inet6_net_init(struct net *net)
 
         net->ipv6.sysctl.bindv6only = 0;
         net->ipv6.sysctl.icmpv6_time = 1*HZ;
+        atomic_set(&net->ipv6.rt_genid, 0);
 
         err = ipv6_init_mibs(net);
         if (err)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 74ab1f74abcd..ce9616304521 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -283,7 +283,7 @@ static inline struct rt6_info *ip6_dst_alloc(struct net *net,
 
                 memset(dst + 1, 0, sizeof(*rt) - sizeof(*dst));
                 rt6_init_peer(rt, table ? &table->tb6_peers : net->ipv6.peers);
-                rt->rt6i_genid = rt_genid(net);
+                rt->rt6i_genid = rt_genid_ipv6(net);
                 INIT_LIST_HEAD(&rt->rt6i_siblings);
         }
         return rt;
@@ -1061,7 +1061,7 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
          * DST_OBSOLETE_FORCE_CHK which forces validation calls down
          * into this function always.
          */
-        if (rt->rt6i_genid != rt_genid(dev_net(rt->dst.dev)))
+        if (rt->rt6i_genid != rt_genid_ipv6(dev_net(rt->dst.dev)))
                 return NULL;
 
         if (rt->rt6i_node && (rt->rt6i_node->fn_sernum == cookie))