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
887c95cc1d
("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@gmail.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
fbfe80c890
commit
3630d40067
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@ -551,6 +551,8 @@ static inline bool rt6_check_neigh(struct rt6_info *rt)
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ret = true;
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#endif
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read_unlock(&neigh->lock);
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} else if (IS_ENABLED(CONFIG_IPV6_ROUTER_PREF)) {
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ret = true;
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}
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rcu_read_unlock_bh();
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