[tor-bugs] #3076 [Tor Client]: Implement 'SocksPort auto' and 'ControlPort auto'

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#3076: Implement 'SocksPort auto' and 'ControlPort auto'
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 Reporter:  mikeperry    |          Owner:                    
     Type:  enhancement  |         Status:  new               
 Priority:  major        |      Milestone:  Tor: 0.2.2.x-final
Component:  Tor Client   |        Version:                    
 Keywords:               |         Parent:  #2264             
   Points:               |   Actualpoints:                    
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Comment(by arma):

 Replying to [comment:5 nickm]:
 > On the interface:
 >
 > I can get that we need to expose the ControlPort via a way that doesn't
 involve using the ControlPort, but is there some reason that we can't use
 a GETINFO command for the other ports?

 Not that I know of.

 > Also, is there any reason to do this _only_ for socksport and
 controlport?

 No.

 > As far as possible, I want to avoid having log messages be any part of
 our defined interface.  If we *did* do that, we'd want to make it really
 obvious which ones they are.

 Right.

 > On the implementation:
 >
 > It seems like "FooPort auto" ought to mean "bind the address with
 sin_port set to 0, then do a getsockname() on the socket, then advertise
 that one."  That doesn't sound too hard.  We would also need to tweak
 anything that advertises a port.

 Ok. I expect "ORPort auto" will want more smarts, for two reasons. First,
 we want to pick one that is reachable, so it's a more complex testing
 process than 'bind and see what the answer is'. Same, I guess, with
 "DirPort auto". Second, we might prefer relays on 443 or 80 or 143 or
 something -- I'd been imagining a function that returns what number we'd
 like to try next and the first few are random skewed toward the numbers
 we'd prefer and after that it goes random. Your idea of "if you meant to
 get a random one, let the kernel decide" is a good one. All of *that*
 said, an ORPort auto that simply binds to an available port would be a
 great start.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/3076#comment:6>
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