[tahoe-lafs-trac-stream] [tahoe-lafs] #1933: announcement seqnums: respond to state-rollback

[tahoe-lafs]

#1933: announcement seqnums: respond to state-rollback
--------------------------+---------------------------
 Reporter:  warner        |          Owner:
     Type:  enhancement   |         Status:  new
 Priority:  normal        |      Milestone:  undecided
Component:  code-network  |        Version:  1.9.2
 Keywords:                |  Launchpad Bug:
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 In the #1767 sequence-number-based introducer announcements fix, we
 deferred a few TODO items:

 1. if a publisher receives its own announcement (same pubkey, valid
 signature) with a higher seqnum, or with an equal seqnum but different
 contents, immediately raise its seqnum to be one higher than the received
 value and re-publish all announcements
 2. if a subscriber receives an annoucement that is older (lower seqnum or
 same-seqnum-different-contents) than what it has remembered for that index
 (index=pubkey+servicename), send the remembered announcement back to the
 publisher (so they can learn about their rollback and perform thing 1
 above)

 The introducer server (while we still have one, e.g. until distributed
 /gossip-based introduction happens) is the best place to notice the
 rollback and tell the publisher, perhaps in the return value from the
 `remote_publish_v2()` method. Other introducer clients should do the same
 thing, but all they can do is publish the stored announcement on the same
 channel (service name) as the original, which the publisher may not be
 listening to (like a storage server who doesn't subscribe to "storage"
 because they don't care).

-- 
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1933>
tahoe-lafs <https://tahoe-lafs.org>
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