4 files changed, 43 insertions, 41 deletions

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index 2e7f1948216f..717902669d2f 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -419,12 +419,9 @@ static void ah4_err(struct sk_buff *skb, u32 info)
         if (!x)
                 return;
 
-        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
-                atomic_inc(&flow_cache_genid);
-                rt_genid_bump(net);
-
+        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
                 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
-        } else
+        else
                 ipv4_redirect(skb, net, 0, 0, IPPROTO_AH, 0);
         xfrm_state_put(x);
 }
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 4cfe34d4cc96..ab3d814bc80a 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -502,12 +502,9 @@ static void esp4_err(struct sk_buff *skb, u32 info)
         if (!x)
                 return;
 
-        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
-                atomic_inc(&flow_cache_genid);
-                rt_genid_bump(net);
-
+        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
                 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
-        } else
+        else
                 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
         xfrm_state_put(x);
 }
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index 59cb8c769056..826be4cb482a 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -47,12 +47,9 @@ static void ipcomp4_err(struct sk_buff *skb, u32 info)
         if (!x)
                 return;
 
-        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
-                atomic_inc(&flow_cache_genid);
-                rt_genid_bump(net);
-
+        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
                 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
-        } else
+        else
                 ipv4_redirect(skb, net, 0, 0, IPPROTO_COMP, 0);
         xfrm_state_put(x);
 }
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 550781a17b34..561a37833d86 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -594,11 +594,25 @@ static inline u32 fnhe_hashfun(__be32 daddr)
         return hval & (FNHE_HASH_SIZE - 1);
 }
 
+static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
+{
+        rt->rt_pmtu = fnhe->fnhe_pmtu;
+        rt->dst.expires = fnhe->fnhe_expires;
+
+        if (fnhe->fnhe_gw) {
+                rt->rt_flags |= RTCF_REDIRECTED;
+                rt->rt_gateway = fnhe->fnhe_gw;
+                rt->rt_uses_gateway = 1;
+        }
+}
+
 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
                                   u32 pmtu, unsigned long expires)
 {
         struct fnhe_hash_bucket *hash;
         struct fib_nh_exception *fnhe;
+        struct rtable *rt;
+        unsigned int i;
         int depth;
         u32 hval = fnhe_hashfun(daddr);
 
@@ -627,8 +641,12 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
                         fnhe->fnhe_gw = gw;
                 if (pmtu) {
                         fnhe->fnhe_pmtu = pmtu;
-                        fnhe->fnhe_expires = expires;
+                        fnhe->fnhe_expires = max(1UL, expires);
                 }
+                /* Update all cached dsts too */
+                rt = rcu_dereference(fnhe->fnhe_rth);
+                if (rt)
+                        fill_route_from_fnhe(rt, fnhe);
         } else {
                 if (depth > FNHE_RECLAIM_DEPTH)
                         fnhe = fnhe_oldest(hash);
@@ -644,6 +662,18 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
                 fnhe->fnhe_gw = gw;
                 fnhe->fnhe_pmtu = pmtu;
                 fnhe->fnhe_expires = expires;
+
+                /* Exception created; mark the cached routes for the nexthop
+                 * stale, so anyone caching it rechecks if this exception
+                 * applies to them.
+                 */
+                for_each_possible_cpu(i) {
+                        struct rtable __rcu **prt;
+                        prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
+                        rt = rcu_dereference(*prt);
+                        if (rt)
+                                rt->dst.obsolete = DST_OBSOLETE_KILL;
+                }
         }
 
         fnhe->fnhe_stamp = jiffies;
@@ -917,13 +947,6 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
         if (mtu < ip_rt_min_pmtu)
                 mtu = ip_rt_min_pmtu;
 
-        if (!rt->rt_pmtu) {
-                dst->obsolete = DST_OBSOLETE_KILL;
-        } else {
-                rt->rt_pmtu = mtu;
-                dst->expires = max(1UL, jiffies + ip_rt_mtu_expires);
-        }
-
         rcu_read_lock();
         if (fib_lookup(dev_net(dst->dev), fl4, &res) == 0) {
                 struct fib_nh *nh = &FIB_RES_NH(res);
@@ -1063,11 +1086,11 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
          * DST_OBSOLETE_FORCE_CHK which forces validation calls down
          * into this function always.
          *
-         * When a PMTU/redirect information update invalidates a
-         * route, this is indicated by setting obsolete to
-         * DST_OBSOLETE_KILL.
+         * When a PMTU/redirect information update invalidates a route,
+         * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
+         * DST_OBSOLETE_DEAD by dst_free().
          */
-        if (dst->obsolete == DST_OBSOLETE_KILL || rt_is_expired(rt))
+        if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
                 return NULL;
         return dst;
 }
@@ -1215,20 +1238,8 @@ static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
                         fnhe->fnhe_pmtu = 0;
                         fnhe->fnhe_expires = 0;
                 }
-                if (fnhe->fnhe_pmtu) {
-                        unsigned long expires = fnhe->fnhe_expires;
-                        unsigned long diff = expires - jiffies;
-
-                        if (time_before(jiffies, expires)) {
-                                rt->rt_pmtu = fnhe->fnhe_pmtu;
-                                dst_set_expires(&rt->dst, diff);
-                        }
-                }
-                if (fnhe->fnhe_gw) {
-                        rt->rt_flags |= RTCF_REDIRECTED;
-                        rt->rt_gateway = fnhe->fnhe_gw;
-                        rt->rt_uses_gateway = 1;
-                } else if (!rt->rt_gateway)
+                fill_route_from_fnhe(rt, fnhe);
+                if (!rt->rt_gateway)
                         rt->rt_gateway = daddr;
 
                 rcu_assign_pointer(fnhe->fnhe_rth, rt);