commit e9038dc5f2fe6a62af1a32e1e4c51d8b894998e1 Author: Mike Perry mikeperry-git@torproject.org Date: Tue Sep 28 15:17:34 2021 +0000

Add a max cwnd consensus parameter and clamp. --- src/core/or/congestion_control_common.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/core/or/congestion_control_common.c b/src/core/or/congestion_control_common.c index 393b79459d..4449d9bfd5 100644 --- a/src/core/or/congestion_control_common.c +++ b/src/core/or/congestion_control_common.c @@ -33,6 +33,7 @@

#define SENDME_INC_DFLT (50) #define CWND_MIN_DFLT (MAX(100, SENDME_INC_DFLT)) +#define CWND_MAX_DFLT (INT32_MAX)

#define CWND_INC_DFLT (50)

@@ -82,6 +83,14 @@ congestion_control_new_consensus_params(const networkstatus_t *ns) OR_CONN_LOWWATER_DFLT, OR_CONN_LOWWATER_MIN, OR_CONN_LOWWATER_MAX); + +#define CWND_MAX_MIN 500 +#define CWND_MAX_MAX (INT32_MAX) + cwnd_max = + networkstatus_get_param(NULL, "cc_cwnd_max", + CWND_MAX_DFLT, + CWND_MAX_MIN, + CWND_MAX_MAX); }

/** @@ -963,20 +972,32 @@ congestion_control_dispatch_cc_alg(congestion_control_t *cc, const circuit_t *circ, const crypt_path_t *layer_hint) { + int ret = -END_CIRC_REASON_INTERNAL; switch (cc->cc_alg) { case CC_ALG_WESTWOOD: - return congestion_control_westwood_process_sendme(cc, circ, layer_hint); + ret = congestion_control_westwood_process_sendme(cc, circ, layer_hint); + break;

case CC_ALG_VEGAS: - return congestion_control_vegas_process_sendme(cc, circ, layer_hint); + ret = congestion_control_vegas_process_sendme(cc, circ, layer_hint); + break;

case CC_ALG_NOLA: - return congestion_control_nola_process_sendme(cc, circ, layer_hint); + ret = congestion_control_nola_process_sendme(cc, circ, layer_hint); + break;

case CC_ALG_SENDME: default: tor_assert(0); }

- return -END_CIRC_REASON_INTERNAL; + if (cc->cwnd > cwnd_max) { + static ratelim_t cwnd_limit = RATELIM_INIT(60); + log_fn_ratelim(&cwnd_limit, LOG_NOTICE, LD_CIRC, + "Congestion control cwnd %"PRIu64" exceeds max %d, clamping.", + cc->cwnd, cwnd_max); + cc->cwnd = cwnd_max; + } + + return ret; }