[tor-bugs] #5617 [Obfsproxy]: obfsproxy: test suite failure (connection refused)

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#5617: obfsproxy: test suite failure (connection refused)
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 Reporter:  asn        |          Owner:  asn
     Type:  defect     |         Status:  new
 Priority:  normal     |      Milestone:     
Component:  Obfsproxy  |        Version:     
 Keywords:             |         Parent:     
   Points:             |   Actualpoints:     
-----------------------+----------------------------------------------------

Comment(by asn):

 Replying to [comment:4 arma]:
 > Replying to [comment:2 asn]:
 > > I suspect that this one is caused by this code:
 > > {{{
 > >         self.output_reader = ReadWorker(("127.0.0.1", EXIT_PORT))
 > >         self.obfs = Obfsproxy(self.obfs_args)
 > >         self.input_chan = connect_with_retry(("127.0.0.1",
 ENTRY_PORT))
 > > }}}
 > >
 > > `ReadWorker` is supposed to listen in `EXIT_PORT`, so that the server-
 side obfsproxy can send it data to read.
 > >
 > > `ReadWorker` is implemented as a `multiprocessing` process, and I
 think that the `Connection refused` error is caused by the race condition
 between `ReadWorker` spawning its python process, and `Obfsproxy` spawing
 its obfsproxy process that tries to connect to `EXIT_PORT`.
 >
 > I know nothing here, but doesn't one of those say ENTRY_PORT?

 `connect_with_retry()` connects to `ENTRY_PORT` to send the file to the
 client-side obfsproxy. The client-side obfsproxy, passes an obfsucated
 version of the file to the server-side obfsproxy, which in turn spits the
 original file back to the `ReadWorker` on `EXIT_PORT`.

 The bug occurs because the server-side obfsproxy tries to connect to
 `EXIT_PORT` when it starts up, but `ReadWorker` still hasn't bound there.

 IOW, the `ENTRY_PORTS` line is not directly related to the bug; it's just
 the line that does the initial connection to the client-side obfsproxy.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5617#comment:5>
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