[tor-bugs] #23502 [Core Tor/Tor]: prop224: Don't make IPv4 mandatory because one day we'll have IPv6 only relays

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#23502: prop224: Don't make IPv4 mandatory because one day we'll have IPv6 only
relays
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 Reporter:  dgoulet                     |          Owner:  dgoulet
     Type:  defect                      |         Status:  merge_ready
 Priority:  Medium                      |      Milestone:  Tor:
                                        |  0.3.2.x-final
Component:  Core Tor/Tor                |        Version:
 Severity:  Normal                      |     Resolution:
 Keywords:  prop224, tor-relay, tor-hs  |  Actual Points:
Parent ID:                              |         Points:
 Reviewer:  asn                         |        Sponsor:
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Comment (by dgoulet):

 Summarizing a bit the IRC discussion and conclusion for the `merge_ready`
 state.

 This patch makes it that we can possibly encode an IPv6 only relay that is
 NO IPv4. Right now, it is not possible for a relay to not have an IPv4 in
 tor so the HS subsystem will always prefer IPv4 in case of a 3-hop.

 For single onion now, the IPv6 is preferred if (1) firewall allow it, and
 (2) it is available of course.

 Now, the other issue is that *both* IPv4 and IPv6 of a relay can NOT be
 included in the link specifier list with current code. It is v4 and if not
 there, v6 if possible. If none are available, we go on error and the
 node_t is discarded.

 For 032 as the feature freeze is today, I think it is OK with what we have
 and we'll make a real IPv6 support for 033 if we can.

 Sounds about right?

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/23502#comment:14>
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