Tor Bridges are special
Tor relays which are not listed in the public relay directory. They are
used to help circumvent censorship by
providing users with connections to the public relays in the Tor
network.
Tor Bridges are different from normal relays in another important way:
they can run what are called Pluggable Transports.
A Pluggable
Transport
is a program which is pluggable — meaning that it is meant to work
with lots of other anonymity and censorship circumvention software, not
just Tor — and is a transport — meaning that it transports your
internet traffic, usually in a way which makes it look different. For
example,
Obfsproxy is
a Pluggable Transport which disguises your traffic by adding an
obfuscating layer of encryption.
Well, probably, you don’t. But if you’re looking for bridges, you can
use the web interface of the
BridgeDB instance deployed by the Tor Project, which has instructions on
getting the Pluggable Transports-capable Tor Browser Bundle, as well as
instructions for getting extra Bridges.
If you’d like to hack on BridgeDB, you might wish to read BridgeDB’s
developer documentation. The rest of
this document mainly concerns mainenance and installation instructions.
BridgeDB requires the following OS-level dependencies:
As well as any Python dependencies in the requirements.txt file.
BridgeDB should work with or without a Python virtualenv.
Install Python 2.7, and other OS-level dependencies. On Debian, you
can do:
sudo apt-get install build-essential openssl python python-dev \
python-setuptools sqlite3 gnupg2 libgeoip-dev geoip-database
Install Pip 1.3.1 or later. Debian has this version, but if for some
reason that or a newer version isn’t available, the easiest way to
install a newer Pip is to use the Pip development teams’s getpip
script:
wget https://raw.github.com/pypa/pip/master/contrib/get-pip.py
sudo python get-pip.py
(virtualenv installs only) Use Pip to install virtualenv and
virtualenvwrapper:
sudo pip install --upgrade virtualenv virtualenvwrapper
(virtualenv installs only) Configure virtualenvwrapper and create a
virtualenv for BridgeDB:
WORKON_HOME=${HOME}/.virtualenvs
export WORKON_HOME
mkdir -p $WORKON_HOME
source $(which virtualenvwrapper.sh)
git clone https://git.torproject.org/bridgedb.git && cd bridgedb
mkvirtualenv -a $PWD -r requirements.txt --unzip-setuptools --setuptools bridgedb
From now on, to use BridgeDB’s virtualenv, just do $ workon bridgedb
(after sourcing virtualenvwrapper.sh, as before). To exit the virtualenv
without exiting the shell, do $ deactivate.
(virtualenv installs only) To install, set PYTHONPATH to include the
root directory of the virtualenv:
export PYTHONPATH=$PYTHONPATH:${VIRTUAL_ENV}/lib/python2.7/site-packages
Then, proceed as usual:
python setup.py install --record installed-files.txt
Using New Translations:
This should be done when newly completed translations are available in
Transifex.
Piece of cake. Running maint/get-completed-translations will take
care of cloning only the bridgedb_completed branch of Tor’s
translations repo
and placing all the updated files in their correct locations.
Requesting Translations for Altered/Added Source Code:
This should be done whenever any of the strings requiring translation –
_("the ones inside the weird underscore function, like this") – are
changed, or new ones are added. See lib/bridgedb/strings.py.
Translations for Tor Project repos are kept in a separate
repo. You’ll need to
extract the strings from BridgeDB’s source code into .pot templates, and
place these .po files into the translation repo in the bridgedb
branch. After than the .po files should be put into Transifex (don’t ask
me how this works…) and translated. After the translations are complete,
the finished .po files should be placed into the bridgedb_completed
branch.
To extract all strings from BridgeDB’s source:
python setup.py extract_messages
A .pot file will be created in ./i18n/templates/bridgedb.pot
Initialise catalogs for each desired language:
python setup.py init_catalog -l LANG
where LANG is the 2 or 4 letter country-code, eg. ‘es’. If you’ve
already initialised a particular language, do instead:
python setup.py update_catalog
Create a self-signed certificate with:
Or, place an existing certificate in the path specified in bridgedb.conf
by the HTTPS_CERT_FILE option, and a private key where
HTTPS_KEY_FILE points to. The defaults are ‘cert’ and ‘privkey.pem’,
respectively.
BridgeDB has two ways to use CAPTCHAs on webpages. The first uses reCaptcha,
an external Google service (this requires an account with them), which
BridgeDB fetches the CAPTCHAs images from for each incoming request from a
client. The second method uses a local cache of pre-made CAPTCHAs, created by
scripting Gimp using gimp-captcha. The latter cannot easily be run on
headless server, unfortunately, because Gimp requires an X server to be
installed.
reCaptcha
To enable fetching CAPTCHAs from the reCaptcha API server, set these
options in bridgedb.conf:
RECAPTCHA_ENABLED
RECAPTCHA_PUB_KEY
RECAPTCHA_SEC_KEY
gimp-captcha
To enable using a local cache of CAPTCHAs, set the following options:
GIMP_CAPTCHA_ENABLED
GIMP_CAPTCHA_DIR
GIMP_CAPTCHA_HMAC_KEYFILE
GIMP_CAPTCHA_RSA_KEYFILE
In your bridgedb.conf file, make sure that:
EMAIL_GPG_SIGNING_ENABLED = True
and edit the following option to add the full fingerprint of the GnuPG key
that should be used to by BridgeDB to sign outgoing emails:
EMAIL_GPG_PRIMARY_KEY_FINGERPRINT
The key specified by EMAIL_GPG_PRIMARY_KEY_FINGERPRINT can be a master
key, or a subkey (with or without the private portions of its corresponding
master key), but it must be inside the secring.gpg and pubring.gpg
keyrings inside the directory specified in the bridgedb.conf option:
If the key has requires a passphrase for signing, you’ll also need to set
either of:
EMAIL_GPG_PASSPHRASE
EMAIL_GPG_PASSPHRASE_FILE
Uncomment or add COUNTRY_BLOCK_FILE to your bridgedb.conf. This file
should contain one bridge entry per line, in the format:
fingerprint <bridge fingerprint> country-code <country code>
If the COUNTRY_BLOCK_FILE file is present, bridgedb will filter
blocked bridges from the responses it gives to clients requesting
bridges.
Before running to any of BridgeDB’s test suites, make sure you have the
additional dependencies in the Pip requirements file,
.test.requirements.txt installed:
pip install -r .test.requirements.txt
To create a bunch of fake bridge descriptors to test BridgeDB, do:
bridgedb mock [-n NUMBER_OF_DESCRIPTORS]
Note that you will need to install
leekspin in order to run the
bridgedb mock command. See doc/HACKING.md for details.
And finally, to run the test suites, do:
If you just want to run the tests, and don’t care about code coverage
statistics, see the bridgedb trial and bridgedb test commands.
To run BridgeDB, simply make any necessary changes to bridgedb.conf, and do:
And remember that all files/directories in bridgedb.conf are assumed
relative to the runtime directory. By default, BridgeDB uses the current
working directory; you can, however specify an a different runtime
directory:
bridgedb -r /srv/bridges.torproject.org/run
Make sure that the files and directories referred to in bridgedb.conf
exist. However, many of them, if not found, will be touched on disk so
that attempts to read/write from/to them will not raise excessive
errors.
When you have new lists of bridges from the Bridge Authority, replace
the old files and do:
Or just give it a SIGHUP:
kill -s SIGHUP `cat .../run/bridgedb.pid`
Obviously, you’ll have to feed it bridge descriptor files from a
BridgeAuthority. There’s currently only one BridgeAuthority in the entire
world, but Tor Project is, of course, very interested in adding support for
multiple BridgeAuthorities so that we can scale our own network, and make it
easier for individual and organisations who wish to run a lot of Tor bridge
relays have an easier time distributing those bridges themselves (if they wish
to do so). If you’d like to fund our work on this, please contact
tor-dev@lists.torproject.org!
Just connect to the appropriate port. (See the HTTPS_PORT and
HTTP_UNENCRYPTED_PORT options in the bridgedb.conf file.)
The HTTPS interface for our BridgeDB instance can be found here.
Any mail sent to the EMAIL_PORT with a destination username as defined by
the EMAIL_USERNAME configuration option (the default is 'bridge',
e.g. bridges@...) and sent from an @riseup.net, @gmail.com, or
@yahoo.com address (by default, but configurable with the
EMAIL_DOMAINS option).
You can email our BridgeDB instance here.
