[tor-bugs] #6757 [Tor Client]: ClientPreferIPv6ORPort not honoured when running with bridges

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#6757: ClientPreferIPv6ORPort not honoured when running with bridges
------------------------+---------------------------------------------------
 Reporter:  ln5         |          Owner:                    
     Type:  defect      |         Status:  needs_review      
 Priority:  normal      |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor Client  |        Version:  Tor: 0.2.4.1-alpha
 Keywords:  ipv6        |         Parent:                    
   Points:              |   Actualpoints:                    
------------------------+---------------------------------------------------
Changes (by ln5):

  * keywords:  => ipv6
  * status:  new => needs_review
  * version:  => Tor: 0.2.4.1-alpha
  * component:  Tor Bridge => Tor Client


Comment:

 Replying to [ticket:6757 ln5]:
 > Since get_configured_bridge_by_routerinfo() returns the same bridge
 > regardless of which routerinfo we pass to it, the first found
 > (seemingly the one configured first in the config file).

 Please ignore that sentence. It's both confusing and pointless.

 In 0.2.4.x, clients running with bridges need to set both
 ClientUseIPv6 and ClientPreferIPv6ORPort in order to connect over
 IPv6. This is regression from 0.2.3.x.

 Based on the assumption that we want i) a Bridge line with an IPv6
 address to imply ClientUseIPv6=1 and b) a Bridge line with an IPv6
 address for a given bridge listed before an IPv4 address for the same
 bridge to imply ClientPreferIPv6ORPort=1, I suggest two changes:

 1. Set and reset node_t.ipv6_preferred in
 rewrite_node_address_for_bridge() based on address family of the
 _bridge_ entry (i.e. first configured IP address matching newly
 arrived router) and the existence of an IPv6 address in the
 _routerinfo_.

 2. have node_get_pref_ipv6_orport() return an IPv6 address when
 UseBridges is set, not only when ClientUseIPv6 is set

 Please review branch bug6757 in my public repo.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6757#comment:4>
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