Bug 4748

squash! Document 0.2.3.x torrc/default-torrc/command line semantics changes

Incorporates fixes suggested by rransom.

Previously, a directory would check the latest NS consensus for
having the signatures the client wanted, and use that consensus's
valid_until time to set the HTTP lifetime.  With this patch, the
directory looks at NS consensus or the microdesc consensus,
depending on what the client asked for.

I don't believe this bug occurs, but there was an XXX023 to make
sure it doesn't.

Previously it duplicated some getrlimit code and content from compat.c;
now it doesn't.

I saw 72% on a test run with 26 circuits. 70% might be a little close to the
line. That, or min_circs is too low and we need to be more patient. We still
need to test/simulate more.

The defense counts the circuit failure rate for each guard for the past N
circuits. Failure is defined as the ability to complete a first hop, but not
finish completing the circuit all the way to the exit.

If the failure rate exceeds a certain amount, a notice is emitted.

If it exceeds a greater amount, a warn is emitted and the guard is disabled.

These values are governed by consensus parameters which we intend to tune as
we perform experiments and statistical simulations.

The warning message of validate_pluggable_transports_config() is
superseded by the changes in the warning message of
connection_or_connect() when the proxy credentials can't be found.

Andrea Shepard authored 12 years ago and Nick Mathewson committed 12 years ago

Don't poll to see if we need to build circuits for timeout data if LearnCircuitBuildTimeout is disabled