3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
[ Upstream commit 3630d40067a21d4dfbadc6002bb469ce26ac5d52 ]
After the removal of rt->n we do not create a neighbour entry at route
insertion time (rt6_bind_neighbour is gone). As long as no neighbour is
created because of "useful traffic" we skip this routing entry because
rt6_check_neigh cannot pick up a valid neighbour (neigh == NULL) and
thus returns false.
This change was introduced by commit
887c95cc1da53f66a5890fdeab13414613010097 ("ipv6: Complete neighbour
entry removal from dst_entry.")
To quote RFC4191:
"If the host has no information about the router's reachability, then
the host assumes the router is reachable."
and also:
"A host MUST NOT probe a router's reachability in the absence of useful
traffic that the host would have sent to the router if it were reachable."
So, just assume the router is reachable and let's rt6_probe do the
rest. We don't need to create a neighbour on route insertion time.
If we don't compile with CONFIG_IPV6_ROUTER_PREF (RFC4191 support)
a neighbour is only valid if its nud_state is NUD_VALID. I did not find
any references that we should probe the router on route insertion time
via the other RFCs. So skip this route in that case.
v2:
a) use IS_ENABLED instead of #ifdefs (thanks to Sergei Shtylyov)
Reported-by: Pierre Emeriaud <petrus.lt@xxxxxxxxx>
Cc: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/route.c | 2 ++
1 file changed, 2 insertions(+)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -547,6 +547,8 @@ static inline bool rt6_check_neigh(struc
ret = true;
#endif
read_unlock(&neigh->lock);
+ } else if (IS_ENABLED(CONFIG_IPV6_ROUTER_PREF)) {
+ ret = true;
}
rcu_read_unlock_bh();
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