[tor-bugs] #7773 [Tor]: Relay does not pick the right IP addr of local node

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#7773: Relay does not pick the right IP addr of local node
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 Reporter:  ciaccio               |          Owner:                    
     Type:  defect                |         Status:  new               
 Priority:  normal                |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor                   |        Version:  Tor: 0.2.4.6-alpha
 Keywords:  multihomed tor-relay  |         Parent:                    
   Points:                        |   Actualpoints:                    
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 My laptop has two network interfaces: eth0, statically configured, in use
 when I'm wired in my office; and ppp0, dynamically configured, when I'm
 abroad and use a 3G wireless interface.

 When I'm on eth0 (LAN), the tor relay works regularly.
 When I'm on the ppp0 (3G wireless), the tor relay works too but the ORPort
 and DirPort are not reachable from the outside, because the relay still
 picks the IP address associated to eth0 (unconnected actually) instead of
 ppp0 (the one in real use).

 This problem probably affects all releases.  One year ago I raised another
 bug ticket on this very same defect (see #5298)

 The defect originates by the following two bugs:

 src/or/config.c:resolve_my_address(), a rather messy (really badly
 written, to be honest) piece of code which mistakenly resolves via
 hostname rather than picking the IP address based on the network interface
 actually in use.  I had to rewrite that function almost from scratch, and
 now it works.

 src/common/address.c:get_interface_address6(): here a list of all net
 devices available is built, but then the first valid one is picked,
 regardless of it being the one actually in use or not (on my laptop it
 always chooses eth0, even if I'm using ppp0). Solved by disabling the list
 of net devices, thus falling back to the default "discovery" mechanism.

 I have patches, if needed.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/7773>
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