The next series of commits begins addressing the issue that we're
currently including the complete or.h file in all of our source files.
To change that, we're splitting function definitions into new header
files (one header file per source file).
We implemented ratelimiting for warnings going into the logfile, but didn't
rate-limit controller events. Now both log warnings and controller events
are rate-limited.
The OutboundBindAddress option is useful for making sure that all of
your outbond connections use a given interface. But when connecting
to 127.0.0.1 (or ::1 even) it's important to actually have the
connection come _from_ localhost, since lots of programs running on
localhost use the source address to authenticate that the connection
is really coming from the same host.
Our old code always bound to OutboundBindAddress, whether connecting
to localhost or not. This would potentially break DNS servers on
localhost, and socks proxies on localhost. This patch changes the
behavior so that we only look at OutboundBindAddress when connecting
to a non-loopback address.
The new rule is: safe_str_X() means "this string is a piece of X
information; make it safe to log." safe_str() on its own means
"this string is a piece of who-knows-what; make it safe to log".
There are two big changes here:
- We store active circuits in a priority queue for each or_conn,
rather than doing a linear search over all the active circuits
before we send each cell.
- Rather than multiplying every circuit's cell-ewma by a decay
factor every time we send a cell (thus normalizing the value of a
current cell to 1.0 and a past cell to alpha^t), we instead
only scale down the cell-ewma every tick (ten seconds atm),
normalizing so that a cell sent at the start of the tick has
value 1.0).
Each circuit is ranked in terms of how many cells from it have been
relayed recently, using a time-weighted average.
This patch has been tested this on a private Tor network on PlanetLab,
and gotten improvements of 12-35% in time it takes to fetch a small
web page while there's a simultaneous large data transfer going on
simultaneously.
[Commit msg by nickm based on mail from Ian Goldberg.]
Some *_free functions threw asserts when passed NULL. Now all of them
accept NULL as input and perform no action when called that way.
This gains us consistence for our free functions, and allows some
code simplifications where an explicit null check is no longer necessary.
