ipv6: Extend the route lookups to low priority metrics.

We search only for routes with highest priority metric in
find_rr_leaf(). However if one of these routes is marked
as invalid, we may fail to find a route even if there is
a appropriate route with lower priority. Then we loose
connectivity until the garbage collector deletes the
invalid route. This typically happens if a host route
expires afer a pmtu event. Fix this by searching also
for routes with a lower priority metric.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 4774f13..07562a2 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -652,15 +652,33 @@ static struct rt6_info *find_rr_leaf(struct fib6_node *fn,
                                     u32 metric, int oif, int strict,
                                     bool *do_rr)
 {
-       struct rt6_info *rt, *match;
+       struct rt6_info *rt, *match, *cont;
        int mpri = -1;
 
        match = NULL;
-       for (rt = rr_head; rt && rt->rt6i_metric == metric;
-            rt = rt->dst.rt6_next)
+       cont = NULL;
+       for (rt = rr_head; rt; rt = rt->dst.rt6_next) {
+               if (rt->rt6i_metric != metric) {
+                       cont = rt;
+                       break;
+               }
+
+               match = find_match(rt, oif, strict, &mpri, match, do_rr);
+       }
+
+       for (rt = fn->leaf; rt && rt != rr_head; rt = rt->dst.rt6_next) {
+               if (rt->rt6i_metric != metric) {
+                       cont = rt;
+                       break;
+               }
+
                match = find_match(rt, oif, strict, &mpri, match, do_rr);
-       for (rt = fn->leaf; rt && rt != rr_head && rt->rt6i_metric == metric;
-            rt = rt->dst.rt6_next)
+       }
+
+       if (match || !cont)
+               return match;
+
+       for (rt = cont; rt; rt = rt->dst.rt6_next)
                match = find_match(rt, oif, strict, &mpri, match, do_rr);
 
        return match;