[tor-bugs] #13338 [Tor]: Rewrite tor-fw-helper in Go (or another memory-safe language)

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#13338: Rewrite tor-fw-helper in Go (or another memory-safe language)
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     Reporter:  arma         |      Owner:  yawning
         Type:  enhancement  |     Status:  needs_review
     Priority:  minor        |  Milestone:  Tor: unspecified
    Component:  Tor          |    Version:
   Resolution:               |   Keywords:  flashproxy
Actual Points:               |  Parent ID:  #5213
       Points:               |
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Comment (by yawning):

 Replying to [comment:23 dcf]:
 > Internal port and external port are the same here (9000). You're
 confused between flashproxy-client args and tor-fw-helper args. `:0` is
 the LOCAL port from
 https://gitweb.torproject.org/flashproxy.git/blob/HEAD:/doc/flashproxy-
 client.1.txt.

 Ah indeed.  I should probably still document that caveat somewhere, even
 though strictly speaking it's a "the router firmware sucks" problem.

 On a related note, how well does flashproxy tolerate the external port
 reported as success being different from the one that's requested?  (Eg:
 You request a port mapping between `192.0.2.10:9000` <-> `0.0.0.0:9000`,
 but the router establishes `192.0.2.10:9000` <-> `0.0.0.0:10000`)

 Right now the helper assumes "it doesn't" even though this can happen with
 NAT-PMP, and treats that as a failure and removes the mapping that was
 created.  If it will do the right thing based on the stdout chatter, then
 (after checking if tor handles it), I'll adjust the code as appropriate
 (The internal port returned over stdout on success will always be what is
 expected).

 There's a way to get UPnP to have this kind of behavior as well, but I'm
 not sure how widely deployed support for `WANIPConnection` version 2 is,
 or how reliable it would be.

 If tor doesn't handle it, then I probably won't bother.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13338#comment:24>
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