[tor-bugs] #13112 [Tor]: Some things are probably broken when we advertise multiple ORPorts and only some are reachable

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#13112: Some things are probably broken when we advertise multiple ORPorts and only
some are reachable
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 Reporter:  andrea  |          Owner:
     Type:  defect  |         Status:  new
 Priority:  normal  |      Milestone:  Tor: 0.2.6.x-final
Component:  Tor     |        Version:  Tor: unspecified
 Keywords:          |  Actual Points:
Parent ID:          |         Points:
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 Observations on reachability testing made while fixing #12160:

  - We only have a 1-bit notion of reachability; if we get an incoming non-
 local connection, we assume reachability in onionskin_answer() and call
 router_orport_found_reachable() to publish a descriptor.

  - We should have a reachability bit per *advertised* ORPort to determine
 its inclusion in the published descriptor, and publish if and only if we
 have one or more reachable ORPorts.

  - To implement this, we need a way to link incoming testing circuits to a
 particular advertised ORPort; we don't know this from the port the
 underlying channel was listening on because reverse proxies might make
 this not one-to-one in general.

  - Arma suggests in IRC that netinfo cells know the IP the connection was
 attempted on and if they were extended with a port number they might
 provide a sufficient mechanism.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13112>
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