[tor-bugs] #9098 [Tor]: Hidden service protocol has IPv4 baked into it

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#9098: Hidden service protocol has IPv4 baked into it
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 Reporter:  andrea  |          Owner:                     
     Type:  defect  |         Status:  new                
 Priority:  major   |      Milestone:  Tor: unspecified   
Component:  Tor     |        Version:  Tor: 0.2.4.14-alpha
 Keywords:          |         Parent:                     
   Points:          |   Actualpoints:                     
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 The current hidden service protocol assumes a single-protocol IPv4
 environment.  Specifically:

 The v2 HS descriptor has exactly one ip-address field per intro point,
 which is parsed by tor_addr_parse().  This will accept an IPv6 address,
 although I haven't checked what the client will do with it if it gets one.
 In a mixed IPv4/v6 environment it's obviously undesirable for there to be
 only one ip-address field per intro point, although possibly a service
 could get around that by listing the IPv4 and IPv6 addresses of a node in
 separate intro points.

 The v2/v3 INTRODUCE cell format have the 4-byte IPv4 address of a
 rendezvous point hard-coded.  This will have to change to something like
 this:

  * 1 byte address family
  * 1 byte address length
  * variable-length address

 ...possibly together with a way for the service to indicate in its
 descriptors what address families it will support in rendezvous points.

 Yeah, I know there's a long list of desired hidden service improvements
 and a Tor network where any nodes don't support IPv4 is far off in the
 future, but I haven't seen this one mentioned before so I thought I'd file
 a bug while I remembered it.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9098>
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