Commit 3630d400 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
Browse files

ipv6: rt6_check_neigh should successfully verify neigh if no NUD information are available

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

 ("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.

a) use IS_ENABLED instead of #ifdefs (thanks to Sergei Shtylyov)
Reported-by: default avatarPierre Emeriaud <>
Cc: YOSHIFUJI Hideaki <>
Signed-off-by: default avatarHannes Frederic Sowa <>
Signed-off-by: default avatarDavid S. Miller <>
parent fbfe80c8
......@@ -551,6 +551,8 @@ static inline bool rt6_check_neigh(struct rt6_info *rt)
ret = true;
ret = true;
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment