commit 3f7f96d9e7aa2254d62d63530c37ee96d4b3abc8 Author: Sebastian Hahn sebastian@torproject.org Date: Tue Apr 19 16:00:41 2011 +0200
Prevent hugely inflated observed bandwidth values
When reading the bw history from the state file, we'd add the 900-second value as traffic that occured during one second. Fix that by adding the average value to each second.
This bug was present since 0.2.0.5-alpha, but was hidden until 0.2.23-alpha when we started using the saved values. --- changes/bug2704_part2 | 5 +++++ src/or/rephist.c | 19 ++++++++++++++++--- 2 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/changes/bug2704_part2 b/changes/bug2704_part2 new file mode 100644 index 0000000..962c8b7 --- /dev/null +++ b/changes/bug2704_part2 @@ -0,0 +1,5 @@ + o Major bugfixes: + - Prevent relays that read their bandwidth history from their state file + from arbitrarily inflating that value. Fixes the second half of bug + 2704, bugfix on tor-0.2.2.23-alpha. + diff --git a/src/or/rephist.c b/src/or/rephist.c index 6034bbc..fb091d5 100644 --- a/src/or/rephist.c +++ b/src/or/rephist.c @@ -1686,11 +1686,24 @@ rep_hist_load_bwhist_state_section(bw_array_t *b, }
if (start < now) { - add_obs(b, start, v); + time_t cur_start = start; + time_t actual_interval_len = s_interval; + uint64_t cur_val = 0; + /* Calculate the average per second. This is the best we can do + * because our state file doesn't have per-second resolution. */ + if (start + s_interval > now) + actual_interval_len = now - start; + cur_val = v / actual_interval_len; + /* This is potentially inefficient, but since we don't do it very + * often it should be ok. */ + while (cur_start < start + actual_interval_len) { + add_obs(b, cur_start, cur_val); + ++cur_start; + } b->max_total = mv; /* This will result in some fairly choppy history if s_interval - * is notthe same as NUM_SECS_BW_SUM_INTERVAL. XXXX */ - start += s_interval; + * is not the same as NUM_SECS_BW_SUM_INTERVAL. XXXX */ + start += actual_interval_len; } } SMARTLIST_FOREACH_END(cp); }