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| author | Jiri Benc <jbenc@redhat.com> | 2013-12-11 13:48:20 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-12-11 16:02:58 -0500 |
| commit | 7e9805696428113e34625a65a30dbc62cb78acc5 (patch) | |
| tree | 3d5c13ae988049a6b4e53ff586826ee7779627a6 /net/core/neighbour.c | |
| parent | e47726683803616c773bc75c88cfb3eb54a8172b (diff) | |
| download | lwn-7e9805696428113e34625a65a30dbc62cb78acc5.tar.gz lwn-7e9805696428113e34625a65a30dbc62cb78acc5.zip | |
ipv6: router reachability probing
RFC 4191 states in 3.5:
When a host avoids using any non-reachable router X and instead sends
a data packet to another router Y, and the host would have used
router X if router X were reachable, then the host SHOULD probe each
such router X's reachability by sending a single Neighbor
Solicitation to that router's address. 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. In any case,
these probes MUST be rate-limited to no more than one per minute per
router.
Currently, when the neighbour corresponding to a router falls into
NUD_FAILED, it's never considered again. Introduce a new rt6_nud_state
value, RT6_NUD_FAIL_PROBE, which suggests the route should not be used but
should be probed with a single NS. The probe is ratelimited by the existing
code. To better distinguish meanings of the failure values, rename
RT6_NUD_FAIL_SOFT to RT6_NUD_FAIL_DO_RR.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/neighbour.c')
| -rw-r--r-- | net/core/neighbour.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 8be82a7f0e0f..bf6f404c04aa 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1238,6 +1238,21 @@ out: } EXPORT_SYMBOL(neigh_update); +/* Update the neigh to listen temporarily for probe responses, even if it is + * in a NUD_FAILED state. The caller has to hold neigh->lock for writing. + */ +void __neigh_set_probe_once(struct neighbour *neigh) +{ + neigh->updated = jiffies; + if (!(neigh->nud_state & NUD_FAILED)) + return; + neigh->nud_state = NUD_PROBE; + atomic_set(&neigh->probes, NEIGH_VAR(neigh->parms, UCAST_PROBES)); + neigh_add_timer(neigh, + jiffies + NEIGH_VAR(neigh->parms, RETRANS_TIME)); +} +EXPORT_SYMBOL(__neigh_set_probe_once); + struct neighbour *neigh_event_ns(struct neigh_table *tbl, u8 *lladdr, void *saddr, struct net_device *dev) |