diff options
Diffstat (limited to 'src/feature/hs/hs_dos.c')
| -rw-r--r-- | src/feature/hs/hs_dos.c | 53 |
1 files changed, 38 insertions, 15 deletions
diff --git a/src/feature/hs/hs_dos.c b/src/feature/hs/hs_dos.c index 19794e09d3..1f7415a280 100644 --- a/src/feature/hs/hs_dos.c +++ b/src/feature/hs/hs_dos.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2019, The Tor Project, Inc. */ +/* Copyright (c) 2019-2020, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** @@ -31,20 +31,23 @@ #include "feature/hs/hs_dos.h" -/* Default value of the allowed INTRODUCE2 cell rate per second. Above that +/** Default value of the allowed INTRODUCE2 cell rate per second. Above that * value per second, the introduction is denied. */ #define HS_DOS_INTRODUCE_DEFAULT_CELL_RATE_PER_SEC 25 -/* Default value of the allowed INTRODUCE2 cell burst per second. This is the +/** Default value of the allowed INTRODUCE2 cell burst per second. This is the * maximum value a token bucket has per second. We thus allow up to this value * of INTRODUCE2 cell per second but the bucket is refilled by the rate value * but never goes above that burst value. */ #define HS_DOS_INTRODUCE_DEFAULT_CELL_BURST_PER_SEC 200 -/* Default value of the consensus parameter enabling or disabling the +/** Default value of the consensus parameter enabling or disabling the * introduction DoS defense. Disabled by default. */ #define HS_DOS_INTRODUCE_ENABLED_DEFAULT 0 +/** INTRODUCE2 rejected request counter. */ +static uint64_t intro2_rejected_count = 0; + /* Consensus parameters. The ESTABLISH_INTRO DoS cell extension have higher * priority than these values. If no extension is sent, these are used only by * the introduction point. */ @@ -62,7 +65,7 @@ get_intro2_enable_consensus_param(const networkstatus_t *ns) HS_DOS_INTRODUCE_ENABLED_DEFAULT, 0, 1); } -/* Return the parameter for the introduction rate per sec. */ +/** Return the parameter for the introduction rate per sec. */ STATIC uint32_t get_intro2_rate_consensus_param(const networkstatus_t *ns) { @@ -71,7 +74,7 @@ get_intro2_rate_consensus_param(const networkstatus_t *ns) 0, INT32_MAX); } -/* Return the parameter for the introduction burst per sec. */ +/** Return the parameter for the introduction burst per sec. */ STATIC uint32_t get_intro2_burst_consensus_param(const networkstatus_t *ns) { @@ -80,7 +83,7 @@ get_intro2_burst_consensus_param(const networkstatus_t *ns) 0, INT32_MAX); } -/* Go over all introduction circuit relay side and adjust their rate/burst +/** Go over all introduction circuit relay side and adjust their rate/burst * values using the global parameters. This is called right after the * consensus parameters might have changed. */ static void @@ -102,7 +105,7 @@ update_intro_circuits(void) smartlist_free(intro_circs); } -/* Set consensus parameters. */ +/** Set consensus parameters. */ static void set_consensus_parameters(const networkstatus_t *ns) { @@ -122,7 +125,7 @@ set_consensus_parameters(const networkstatus_t *ns) * Public API. */ -/* Initialize the INTRODUCE2 token bucket for the DoS defenses using the +/** Initialize the INTRODUCE2 token bucket for the DoS defenses using the * consensus/default values. We might get a cell extension that changes those * later but if we don't, the default or consensus parameters are used. */ void @@ -138,7 +141,7 @@ hs_dos_setup_default_intro2_defenses(or_circuit_t *circ) (uint32_t) approx_time()); } -/* Called when the consensus has changed. We might have new consensus +/** Called when the consensus has changed. We might have new consensus * parameters to look at. */ void hs_dos_consensus_has_changed(const networkstatus_t *ns) @@ -152,7 +155,7 @@ hs_dos_consensus_has_changed(const networkstatus_t *ns) set_consensus_parameters(ns); } -/* Return true iff an INTRODUCE2 cell can be sent on the given service +/** Return true iff an INTRODUCE2 cell can be sent on the given service * introduction circuit. */ bool hs_dos_can_send_intro2(or_circuit_t *s_intro_circ) @@ -163,12 +166,12 @@ hs_dos_can_send_intro2(or_circuit_t *s_intro_circ) * This can be set by the consensus, the ESTABLISH_INTRO cell extension or * the hardcoded values in tor code. */ if (!s_intro_circ->introduce2_dos_defense_enabled) { - return true; + goto allow; } /* Should not happen but if so, scream loudly. */ if (BUG(TO_CIRCUIT(s_intro_circ)->purpose != CIRCUIT_PURPOSE_INTRO_POINT)) { - return false; + goto disallow; } /* This is called just after we got a valid and parsed INTRODUCE1 cell. The @@ -189,10 +192,30 @@ hs_dos_can_send_intro2(or_circuit_t *s_intro_circ) } /* Finally, we can send a new INTRODUCE2 if there are still tokens. */ - return token_bucket_ctr_get(&s_intro_circ->introduce2_bucket) > 0; + if (token_bucket_ctr_get(&s_intro_circ->introduce2_bucket) > 0) { + goto allow; + } + + /* If we reach this point, then it means the bucket has reached zero, and + we're going to disallow. */ + + disallow: + /* Increment stats counter, we are rejecting the INTRO2 cell. */ + intro2_rejected_count++; + return false; + + allow: + return true; +} + +/** Return rolling count of rejected INTRO2. */ +uint64_t +hs_dos_get_intro2_rejected_count(void) +{ + return intro2_rejected_count; } -/* Initialize the onion service Denial of Service subsystem. */ +/** Initialize the onion service Denial of Service subsystem. */ void hs_dos_init(void) { |