[tor-bugs] #18998 [Core Tor/Tor]: Relays should accept RENDEZVOUS1 cells of variable size

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#18998: Relays should accept RENDEZVOUS1 cells of variable size
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     Reporter:  special       |      Owner:
         Type:  enhancement   |     Status:  new
     Priority:  Medium        |  Milestone:  Tor: 0.2.9.x-final
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:  tor-hs
Actual Points:                |  Parent ID:  #17241
       Points:                |   Reviewer:
      Sponsor:                |
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 In rend_mid_rendezvous, we require that the RENDEZVOUS1 cell has precisely
 DH_KEY_LEN+DIGEST_LEN bytes of handshake info, which is passed verbatim to
 the service in the RENDEZVOUS2 cell.

 For prop 224, we want to use these same cells. Prop 224 redefines
 RENDEZVOUS1 to be:

     RENDEZVOUS_COOKIE [20 bytes]
     HANDSHAKE_INFO [variable; to end of cell]

 Prop 224's HANDSHAKE_INFO is much shorter. To remain compatible with older
 RPs, we will need to pad these cells in prop 224. Still, we should start
 accepting RENDEZVOUS1 cells of any size, and forward everything after the
 cookie verbatim in the RENDEZVOUS2 cell.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18998>
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