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| author | Lu Feng <lu.feng@6wind.com> | 2014-02-21 08:11:15 +0000 |
|---|---|---|
| committer | David Lamparter <equinox@opensourcerouting.org> | 2014-05-14 16:46:28 +0200 |
| commit | 49d7af115177d05bd66d3115cbacd56a7591ec5e (patch) | |
| tree | 7082972f63b091f0e8bcbbf9a285fe10e5136a8d /ospfd | |
| parent | 4b4bda9bb1913579bd54667f62fafe58e2746478 (diff) | |
| download | quagga-49d7af115177d05bd66d3115cbacd56a7591ec5e.tar.bz2 quagga-49d7af115177d05bd66d3115cbacd56a7591ec5e.tar.xz | |
ospfd: check the LS-Ack's recentness instead of only comparing the #seq
ISSUE:
RTA(DR)-----(BackupDR)RTB
RTA advertises a new LSA to RTB, and then flushes the LSA (with setting
the age of the LSA to MaxAge) within 1 second. Then the LSA is deleted
from RTA, while it still exists on RTB with non-MaxAge and can not be
flushed any more.
FIX:
The reason can be explained in below:
a) RTA -- new LSA, #seq=1 --> RTB (RTB will send the delayed Ack in 1s)
b) RTA -- MaxAge LSA, #seq=1 --> RTB (RTB discards it for the MIN_LS_ARRIVAL)
c) RTA <-- Ack for the new LSA, #seq=1 -- RTB (RTA accepts it)
In the step c), ospf_ls_ack() compares the #seq of the entry in the LS-Ack
with that of local MaxAge LSA. The #seq of the two entries are same. So
the Ack is accepted and the LSA is removed from the retransmit-list (while
it should not).
In RFC2328, section 13.7. Receiving link state acknowledgments:
o If the acknowledgment is for the same instance that is <==
contained on the list, remove the item from the list and
examine the next acknowledgment. Otherwise:
where "same instance" does not mean the same #seq. We must call
ospf_lsa_more_recent() to check whether the two instances are same.
Signed-off-by: Feng Lu <lu.feng@6wind.com>
Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Diffstat (limited to 'ospfd')
| -rw-r--r-- | ospfd/ospf_packet.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c index ab68bf0b..cce56fc6 100644 --- a/ospfd/ospf_packet.c +++ b/ospfd/ospf_packet.c @@ -2120,7 +2120,7 @@ ospf_ls_ack (struct ip *iph, struct ospf_header *ospfh, lsr = ospf_ls_retransmit_lookup (nbr, lsa); - if (lsr != NULL && lsr->data->ls_seqnum == lsa->data->ls_seqnum) + if (lsr != NULL && ospf_lsa_more_recent (lsr, lsa) == 0) { #ifdef HAVE_OPAQUE_LSA if (IS_OPAQUE_LSA (lsr->data->type)) |