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ipv6: Stop /128 route from disappearing after pmtu update
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This patch is mostly from Steffen Klassert <steffen.klassert@secunet.com>.
I only removed the (rt6->rt6i_dst.plen == 128) check from
ip6_rt_update_pmtu() because the (rt6->rt6i_flags & RTF_CACHE) test
has already implied it.

This patch:
1. Create RTF_CACHE route for /128 non local route
2. After (1), all routes that allow pmtu update should have a RTF_CACHE
   clone.  Hence, stop updating MTU for any non RTF_CACHE route.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Martin KaFai Lau authored and David S. Miller committed May 2, 2015
1 parent 9fbdcfa commit 653437d
Showing 1 changed file with 2 additions and 2 deletions.
4 changes: 2 additions & 2 deletions net/ipv6/route.c
Original file line number Diff line number Diff line change
Expand Up @@ -977,7 +977,7 @@ static struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,

if (!(rt->rt6i_flags & (RTF_NONEXTHOP | RTF_GATEWAY)))
nrt = rt6_alloc_cow(rt, &fl6->daddr, &fl6->saddr);
else if (!(rt->dst.flags & DST_HOST))
else if (!(rt->dst.flags & DST_HOST) || !(rt->dst.flags & RTF_LOCAL))
nrt = rt6_alloc_clone(rt, &fl6->daddr);
else
goto out2;
Expand Down Expand Up @@ -1172,7 +1172,7 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
struct rt6_info *rt6 = (struct rt6_info *)dst;

dst_confirm(dst);
if (mtu < dst_mtu(dst) && rt6->rt6i_dst.plen == 128) {
if (mtu < dst_mtu(dst) && (rt6->rt6i_flags & RTF_CACHE)) {
struct net *net = dev_net(dst->dev);

rt6->rt6i_flags |= RTF_MODIFIED;
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