Found by testing with chutney. The old behavior was "fail an
assertion", which obviously isn't optimal.
Bugfix on 8b9a2cb68b290e550695124d7ef0511225b451d5; bug not in any
released version.
In circuitlist_free_all, we free all the circuits, removing them from
the map as we go, but we weren't actually freeing the placeholder
entries that we use to indicate pending DESTROY cells.
Fix for bug 11278; bugfix on the 7912 code that was merged in
0.2.5.1-alpha
This contains the obvious implementation using the circuitmux data
structure. It also runs the old (slow) algorithm and compares
the results of the two to make sure that they're the same.
Needs review and testing.
In a couple of places, to implement the OOM-circuit-killer defense
against sniper attacks, we have counters to remember the age of
cells or data chunks. These timers were based on wall clock time,
which can move backwards, thus giving roll-over results for our age
calculation. This commit creates a low-budget monotonic time, based
on ratcheting gettimeofday(), so that even in the event of a time
rollback, we don't do anything _really_ stupid.
A future version of Tor should update this function to do something
even less stupid here, like employ clock_gettime() or its kin.
On busy servers, this function takes up something like 3-7% in
different profiles, and gets invoked every time we need to participate
as the midpoint in a hidden service.
So maybe walking through a linked list of all the circuits here wasn't
a good idea.
This patch splits out some of the functions in OOM handling so that
it's easier to check them without involving the rest of Tor or
requiring that the circuits be "wired up".
Right now this accounts for about 1% of circuits over all, but if you
pick a guard that's running 0.2.3, it will be about 6% of the circuits
running through that guard.
Making sure that every circuit has at least one ntor link means that
we're getting plausibly good forward secrecy on every circuit.
This implements ticket 9777,
Conflicts:
src/or/or.h
src/or/relay.c
Conflicts were simple to resolve. More fixes were needed for
compilation, including: reinstating the tv_to_msec function, and renaming
*_conn_cells to *_chan_cells.
Previously, when we ran low on memory, we'd close whichever circuits
had the most queued cells. Now, we close those that have the
*oldest* queued cells, on the theory that those are most responsible
for us running low on memory, and that those are the least likely to
actually drain on their own if we wait a little longer.
Based on analysis from a forthcoming paper by Jansen, Tschorsch,
Johnson, and Scheuermann. Fixes bug 9093.
There were only two functions outside of circuitstats that actually
wanted to know what was inside this. Making the structure itself
hidden should help isolation and prevent us from spaghettifying the
thing more.
This implements "algorithm 1" from my discussion of bug #9072: on OOM,
find the circuits with the longest queues, and kill them. It's also a
fix for #9063 -- without the side-effects of bug #9072.
The memory bounds aren't perfect here, and you need to be sure to
allow some slack for the rest of Tor's usage.
This isn't a perfect fix; the rest of the solutions I describe on
codeable.
