[tor-relays] New obfsproxy transport: scramblesuit [bridge operators: please upgrade!]

[George Kadianakis]

Matt <matt at pagan.io> writes:

> On Wed, 12 Feb 2014 18:29:26 +0000
> Matt <matt at pagan.io> wrote:
>
>> I installed obfsproxy through pip. Running Tor 0.2.5.1, I'm seeing
>> this message:
>> 
>> [warn] Managed proxy at '/usr/local/bin/obfsproxy' failed the
>> configuration protocol and will be destroyed.
>> 
>> That doesn't sound too great. What does this message mean?
>> 
>
> Here is more from the debug log:
>
> Feb 12 16:38:27.000 [debug] onion_extend_cpath(): Path is complete: 3
> steps long 
> Feb 12 16:38:27.000 [debug] circuit_handle_first_hop():
> Looking for firsthop '[redacted IPv4]:443' 
> Feb 12 16:38:27.000 [debug] circuit_handle_first_hop(): Conn open.
> Delivering first onion skin. 
> Feb 12 16:38:27.000 [debug] circuit_send_next_onion_skin(): First skin;
> sending create cell. 
> Feb 12 16:38:27.000 [debug] circuit_get_by_circid_channel_impl():
> circuit_get_by_circid_channel_impl() found nothing for circ_id
> 2147489864, channel ID 2 (0x2ba73fe349b0) 
> Feb 12 16:38:27.000 [debug] circuit_deliver_create_cell(): Chosen
> circID 2147489864. 
> Feb 12 16:38:27.000 [debug] circuitmux_attach_circuit(): Attaching
> circuit 2147489864 on channel 2 to cmux 0x2ba73f9a1c90 
> Feb 12 16:38:27.000 [debug] circuitmux_attach_circuit(): Attaching
> circuit 2147489864 on channel 2 to cmux 0x2ba73f9a1c90 
> Feb 12 16:38:27.000 [debug] append_cell_to_circuit_queue(): Made a
> circuit active. 
> Feb 12 16:38:27.000 [info] circuit_send_next_onion_skin(): First hop:
> finished sending CREATE cell to
> '$5A0EF08FC99F236C5E48FB52E649F092088D009C=ganooloonix at [redacted
> IPv4]' 
> Feb 12 16:38:27.000 [debug] pt_configure_remaining_proxies():
> Configuring remaining managed proxies (1)! 
> Feb 12 16:38:27.000 [info] handle_proxy_line(): Got a line from managed
> proxy '/usr/local/bin/obfsproxy': (VERSION 1) 
> Feb 12 16:38:27.000 [info] handle_proxy_line(): Got a line from managed
> proxy '/usr/local/bin/obfsproxy': (SMETHOD-ERROR obfs3 Could not set up
> listener.) 
> Feb 12 16:38:27.000 [warn] Server managed proxy encountered
> a method error. (obfs3 Could not set up listener.) 
> Feb 12 16:38:27.000 [warn] Managed proxy at '/usr/local/bin/obfsproxy'
> failed the configuration protocol and will be destroyed. 
>

Hm, the "Could not set up listener" error message usually appears when
something is already listening on the port that obfsproxy wants to
bind to (Twisted throws the error.CannotListenError exception).

I just pushed a commit to obfsproxy (2e88b52) that should make this
error message more useful (for example, it will print the IP:port that
obfsproxy is trying to bind to). If you want, try fetching the latest
git master of obfsproxy and do the same thing. The error message this
time should be more helpful.