route: also update fnhe_genid when updating a route cache

[ Upstream commit cebe84c6190d741045a322f5343f717139993c08 ]

Now when ip route flush cache and it turn out all fnhe_genid != genid.
If a redirect/pmtu icmp packet comes and the old fnhe is found and all
it's members but fnhe_genid will be updated.

Then next time when it looks up route and tries to rebind this fnhe to
the new dst, the fnhe will be flushed due to fnhe_genid != genid. It
causes this redirect/pmtu icmp packet acutally not to be applied.

This patch is to also reset fnhe_genid when updating a route cache.

Fixes: 5aad1de5ea2c ("ipv4: use separate genid for next hop exceptions")
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 3d9f1c2f81c58afb45a1445f6ed06a97203606a1..aa659433a97395cdc3fc96e06c5834a091e766fc 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -651,9 +651,12 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
        struct fnhe_hash_bucket *hash;
        struct fib_nh_exception *fnhe;
        struct rtable *rt;
+       u32 genid, hval;
        unsigned int i;
        int depth;
-       u32 hval = fnhe_hashfun(daddr);
+
+       genid = fnhe_genid(dev_net(nh->nh_dev));
+       hval = fnhe_hashfun(daddr);
 
        spin_lock_bh(&fnhe_lock);
 
@@ -676,6 +679,8 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
        }
 
        if (fnhe) {
+               if (fnhe->fnhe_genid != genid)
+                       fnhe->fnhe_genid = genid;
                if (gw)
                        fnhe->fnhe_gw = gw;
                if (pmtu) {
@@ -700,7 +705,7 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
                        fnhe->fnhe_next = hash->chain;
                        rcu_assign_pointer(hash->chain, fnhe);
                }
-               fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
+               fnhe->fnhe_genid = genid;
                fnhe->fnhe_daddr = daddr;
                fnhe->fnhe_gw = gw;
                fnhe->fnhe_pmtu = pmtu;