From 833d027778ba97020fb5ded1d94e4b21fbcab766 Mon Sep 17 00:00:00 2001 From: Nick Mathewson Date: Wed, 26 Feb 2014 09:51:30 -0500 Subject: Monotonize the OOM-killer data timers 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. --- src/or/buffers.c | 2 +- src/or/circuitlist.c | 2 +- src/or/relay.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'src/or') diff --git a/src/or/buffers.c b/src/or/buffers.c index 352e60a979..b16ee6efa7 100644 --- a/src/or/buffers.c +++ b/src/or/buffers.c @@ -632,7 +632,7 @@ buf_add_chunk_with_capacity(buf_t *buf, size_t capacity, int capped) chunk = chunk_new_with_alloc_size(preferred_chunk_size(capacity)); } - tor_gettimeofday_cached(&now); + tor_gettimeofday_cached_monotonic(&now); chunk->inserted_time = (uint32_t)tv_to_msec(&now); if (buf->tail) { diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c index 45fc95b561..0534e35553 100644 --- a/src/or/circuitlist.c +++ b/src/or/circuitlist.c @@ -1551,7 +1551,7 @@ circuits_handle_oom(size_t current_allocation) mem_to_recover = current_allocation - mem_target; } - tor_gettimeofday_cached(&now); + tor_gettimeofday_cached_monotonic(&now); now_ms = (uint32_t)tv_to_msec(&now); /* This algorithm itself assumes that you've got enough memory slack diff --git a/src/or/relay.c b/src/or/relay.c index e6d0f50aca..4cbc8fa471 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -1906,7 +1906,7 @@ cell_queue_append_packed_copy(cell_queue_t *queue, const cell_t *cell) { struct timeval now; packed_cell_t *copy = packed_cell_copy(cell); - tor_gettimeofday_cached(&now); + tor_gettimeofday_cached_monotonic(&now); copy->inserted_time = (uint32_t)tv_to_msec(&now); /* Remember the time when this cell was put in the queue. */ -- cgit v1.2.3-54-g00ecf