Merge tag 'media/v4.16-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...

[sfrench/cifs-2.6.git] / net / ipv6 / route.c

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 9dcfadddd800557e6c710a8e848dbfdb7d186393..b0d5c64e19780ce94feb112285ed1d85dbe07e9e 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -128,7 +128,7 @@ struct uncached_list {
 
 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt6_uncached_list);
 
-static void rt6_uncached_list_add(struct rt6_info *rt)
+void rt6_uncached_list_add(struct rt6_info *rt)
 {
        struct uncached_list *ul = raw_cpu_ptr(&rt6_uncached_list);
 
@@ -139,7 +139,7 @@ static void rt6_uncached_list_add(struct rt6_info *rt)
        spin_unlock_bh(&ul->lock);
 }
 
-static void rt6_uncached_list_del(struct rt6_info *rt)
+void rt6_uncached_list_del(struct rt6_info *rt)
 {
        if (!list_empty(&rt->rt6i_uncached)) {
                struct uncached_list *ul = rt->rt6i_uncached_list;
@@ -1509,7 +1509,30 @@ static void rt6_exceptions_remove_prefsrc(struct rt6_info *rt)
        }
 }
 
-static void rt6_exceptions_update_pmtu(struct rt6_info *rt, int mtu)
+static bool rt6_mtu_change_route_allowed(struct inet6_dev *idev,
+                                        struct rt6_info *rt, int mtu)
+{
+       /* If the new MTU is lower than the route PMTU, this new MTU will be the
+        * lowest MTU in the path: always allow updating the route PMTU to
+        * reflect PMTU decreases.
+        *
+        * If the new MTU is higher, and the route PMTU is equal to the local
+        * MTU, this means the old MTU is the lowest in the path, so allow
+        * updating it: if other nodes now have lower MTUs, PMTU discovery will
+        * handle this.
+        */
+
+       if (dst_mtu(&rt->dst) >= mtu)
+               return true;
+
+       if (dst_mtu(&rt->dst) == idev->cnf.mtu6)
+               return true;
+
+       return false;
+}
+
+static void rt6_exceptions_update_pmtu(struct inet6_dev *idev,
+                                      struct rt6_info *rt, int mtu)
 {
        struct rt6_exception_bucket *bucket;
        struct rt6_exception *rt6_ex;
@@ -1518,20 +1541,22 @@ static void rt6_exceptions_update_pmtu(struct rt6_info *rt, int mtu)
        bucket = rcu_dereference_protected(rt->rt6i_exception_bucket,
                                        lockdep_is_held(&rt6_exception_lock));
 
-       if (bucket) {
-               for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
-                       hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
-                               struct rt6_info *entry = rt6_ex->rt6i;
-                               /* For RTF_CACHE with rt6i_pmtu == 0
-                                * (i.e. a redirected route),
-                                * the metrics of its rt->dst.from has already
-                                * been updated.
-                                */
-                               if (entry->rt6i_pmtu && entry->rt6i_pmtu > mtu)
-                                       entry->rt6i_pmtu = mtu;
-                       }
-                       bucket++;
+       if (!bucket)
+               return;
+
+       for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
+               hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
+                       struct rt6_info *entry = rt6_ex->rt6i;
+
+                       /* For RTF_CACHE with rt6i_pmtu == 0 (i.e. a redirected
+                        * route), the metrics of its rt->dst.from have already
+                        * been updated.
+                        */
+                       if (entry->rt6i_pmtu &&
+                           rt6_mtu_change_route_allowed(idev, entry, mtu))
+                               entry->rt6i_pmtu = mtu;
                }
+               bucket++;
        }
 }
 
@@ -3809,25 +3834,13 @@ static int rt6_mtu_change_route(struct rt6_info *rt, void *p_arg)
           Since RFC 1981 doesn't include administrative MTU increase
           update PMTU increase is a MUST. (i.e. jumbo frame)
         */
-       /*
-          If new MTU is less than route PMTU, this new MTU will be the
-          lowest MTU in the path, update the route PMTU to reflect PMTU
-          decreases; if new MTU is greater than route PMTU, and the
-          old MTU is the lowest MTU in the path, update the route PMTU
-          to reflect the increase. In this case if the other nodes' MTU
-          also have the lowest MTU, TOO BIG MESSAGE will be lead to
-          PMTU discovery.
-        */
        if (rt->dst.dev == arg->dev &&
-           dst_metric_raw(&rt->dst, RTAX_MTU) &&
            !dst_metric_locked(&rt->dst, RTAX_MTU)) {
                spin_lock_bh(&rt6_exception_lock);
-               if (dst_mtu(&rt->dst) >= arg->mtu ||
-                   (dst_mtu(&rt->dst) < arg->mtu &&
-                    dst_mtu(&rt->dst) == idev->cnf.mtu6)) {
+               if (dst_metric_raw(&rt->dst, RTAX_MTU) &&
+                   rt6_mtu_change_route_allowed(idev, rt, arg->mtu))
                        dst_metric_set(&rt->dst, RTAX_MTU, arg->mtu);
-               }
-               rt6_exceptions_update_pmtu(rt, arg->mtu);
+               rt6_exceptions_update_pmtu(idev, rt, arg->mtu);
                spin_unlock_bh(&rt6_exception_lock);
        }
        return 0;
@@ -4099,6 +4112,7 @@ static int ip6_route_multipath_add(struct fib6_config *cfg,
                                r_cfg.fc_encap_type = nla_get_u16(nla);
                }
 
+               r_cfg.fc_flags |= (rtnh->rtnh_flags & RTNH_F_ONLINK);
                rt = ip6_route_info_create(&r_cfg, extack);
                if (IS_ERR(rt)) {
                        err = PTR_ERR(rt);