commit 248cbc2d2207a0bc3374cd18a17cda9d1b8a8ef1 Author: George Kadianakis desnacked@riseup.net Date: Mon Sep 7 13:17:41 2020 +0300

statistics: Properly count all rendezvous cells (avoid undercounting).

tl;dr We were not counting cells flying from the client to the service, but we were counting cells flying from the service to the client.

When a rendezvous cell arrives from the client to the RP, the RP forwards it to the service.

For this to happen, the cell first passes through command_process_relay_cell() which normally does the statistics counting. However because the `rend_circ` circuit was not flagged with `circuit_carries_hs_traffic_stats` in rend_mid_rendezvous(), the cell is not counted there.

Then the cell goes to circuit_receive_relay_cell() which has a special code block based on `rend_splice` specifically for rendezvous cells, and the cell gets directly passed to `rend_circ` via a direct call to circuit_receive_relay_cell(). The cell never passes through command_process_relay_cell() ever again and hence is never counted by our rephist module.

The fix here is to flag the `rend_circ` circuit with `circuit_carries_hs_traffic_stats` so that the cell is counted as soon as it hits command_process_relay_cell().

Furthermore we avoid double-counting cells since the special code block of circuit_receive_relay_cell() makes us count rendezvous cells only as they enter the RP and not as they exit it.

Fixes #40117. --- changes/bug40117 | 5 +++++ src/feature/rend/rendmid.c | 6 ++++-- 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/changes/bug40117 b/changes/bug40117 new file mode 100644 index 0000000000..77646edf9c --- /dev/null +++ b/changes/bug40117 @@ -0,0 +1,5 @@ + o Major bugfixes (stats, onion services): + - Fix a bug where we were undercounting the Tor network's total onion + service traffic, by only counting rendezvous traffic originating from + services and ignoring any traffic originating from clients. Fixes bug + 40117; bugfix on 0.2.6.2-alpha. diff --git a/src/feature/rend/rendmid.c b/src/feature/rend/rendmid.c index 3ba48f8858..af02b34e6b 100644 --- a/src/feature/rend/rendmid.c +++ b/src/feature/rend/rendmid.c @@ -333,10 +333,12 @@ rend_mid_rendezvous(or_circuit_t *circ, const uint8_t *request, goto err; }

- /* Statistics: Mark this circuit as an RP circuit so that we collect - stats from it. */ + /* Statistics: Mark circuits as RP circuits */ if (options->HiddenServiceStatistics) { + /* `circ` is the RP <-> service circuit */ circ->circuit_carries_hs_traffic_stats = 1; + /* `rend_circ` is the client <-> RP circuit */ + rend_circ->circuit_carries_hs_traffic_stats = 1; }

/* Send the RENDEZVOUS2 cell to the client. */