[tor-bugs] #23276 [Core Tor/Tor]: RELAY_CONNECTED cells reponding to RELAY_BEGIN_DIR cells don't have a payload

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#23276: RELAY_CONNECTED cells reponding to RELAY_BEGIN_DIR cells don't have a
payload
------------------------------+--------------------------------
     Reporter:  teor          |      Owner:  (none)
         Type:  defect        |     Status:  new
     Priority:  Medium        |  Milestone:  Tor: 0.3.2.x-final
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:  tor-spec
Actual Points:                |  Parent ID:  #18856
       Points:  0.2           |   Reviewer:
      Sponsor:                |
------------------------------+--------------------------------
 But there are only two RELAY_CONNECTED cell formats listed in the spec,
 and they both have payloads:
 {{{
    Otherwise, the exit node replies with a RELAY_CONNECTED cell, whose
    payload is in one of the following formats:
        The IPv4 address to which the connection was made [4 octets]
        A number of seconds (TTL) for which the address may be cached [4
 octets]
     or
        Four zero-valued octets [4 octets]
        An address type (6)     [1 octet]
        The IPv6 address to which the connection was made [16 octets]
        A number of seconds (TTL) for which the address may be cached [4
 octets]
 }}}
 https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt#n1368

 And the RELAY_BEGIN_DIR section could make this explicit, but doesn't:
 {{{
    If a Tor relay is a directory server, it should respond to a
    RELAY_BEGIN_DIR cell as if it had received a BEGIN cell requesting a
    connection to its directory port.  RELAY_BEGIN_DIR cells ignore exit
    policy, since the stream is local to the Tor process.

    ...

    Clients MUST generate an all-zero payload for RELAY_BEGIN_DIR cells,
    and relays MUST ignore the payload.
 }}}

 https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt#n1406

 We could add:

 {{{
    Relays MUST also return an all-zero payload in RELAY_CONNECTED cells
    sent in response to RELAY_BEGIN_DIR cells, and clients MUST ignore the
    payload.
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/23276>
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