diff options
Diffstat (limited to 'src/core/or/dos.c')
| -rw-r--r-- | src/core/or/dos.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/src/core/or/dos.c b/src/core/or/dos.c index ccdb30dbee..b789f87aae 100644 --- a/src/core/or/dos.c +++ b/src/core/or/dos.c @@ -79,6 +79,24 @@ static uint64_t conn_num_addr_connect_rejected; static uint32_t dos_num_circ_max_outq; /* + * Stream denial of service mitigation. + * + * Namespace used for this mitigation framework is "dos_stream_". + */ + +/* Is the connection DoS mitigation enabled? */ +static unsigned int dos_stream_enabled = 0; + +/* Consensus parameters. They can be changed when a new consensus arrives. + * They are initialized with the hardcoded default values. */ +static dos_stream_defense_type_t dos_stream_defense_type; +static uint32_t dos_stream_rate = DOS_STREAM_RATE_DEFAULT; +static uint32_t dos_stream_burst = DOS_STREAM_BURST_DEFAULT; + +/* Keep some stats for the heartbeat so we can report out. */ +static uint64_t stream_num_rejected; + +/* * General interface of the denial of service mitigation subsystem. */ @@ -258,6 +276,59 @@ get_param_conn_connect_defense_time_period(const networkstatus_t *ns) INT32_MAX); } +/* Return true iff the stream creation mitigation is enabled. We look at the + * consensus for this else a default value is returned. */ +MOCK_IMPL(STATIC unsigned int, +get_param_stream_enabled, (const networkstatus_t *ns)) +{ + if (dos_get_options()->DoSStreamCreationEnabled != -1) { + return dos_get_options()->DoSStreamCreationEnabled; + } + + return !!networkstatus_get_param(ns, "DoSStreamCreationEnabled", + DOS_STREAM_ENABLED_DEFAULT, 0, 1); +} + +/* Return the parameter for the time rate that is how many stream per circuit + * over this time span. */ +static uint32_t +get_param_stream_rate(const networkstatus_t *ns) +{ + /* This is in seconds. */ + if (dos_get_options()->DoSStreamCreationRate) { + return dos_get_options()->DoSStreamCreationRate; + } + return networkstatus_get_param(ns, "DoSStreamCreationRate", + DOS_STREAM_RATE_DEFAULT, + 1, INT32_MAX); +} + +/* Return the parameter for the maximum circuit count for the circuit time + * rate. */ +static uint32_t +get_param_stream_burst(const networkstatus_t *ns) +{ + if (dos_get_options()->DoSStreamCreationBurst) { + return dos_get_options()->DoSStreamCreationBurst; + } + return networkstatus_get_param(ns, "DoSStreamCreationBurst", + DOS_STREAM_BURST_DEFAULT, + 1, INT32_MAX); +} + +/* Return the consensus parameter of the circuit creation defense type. */ +static uint32_t +get_param_stream_defense_type(const networkstatus_t *ns) +{ + if (dos_get_options()->DoSStreamCreationDefenseType) { + return dos_get_options()->DoSStreamCreationDefenseType; + } + return networkstatus_get_param(ns, "DoSStreamCreationDefenseType", + DOS_STREAM_DEFENSE_TYPE_DEFAULT, + DOS_STREAM_DEFENSE_NONE, + DOS_STREAM_DEFENSE_MAX); +} + /* Set circuit creation parameters located in the consensus or their default * if none are present. Called at initialization or when the consensus * changes. */ @@ -283,6 +354,12 @@ set_dos_parameters(const networkstatus_t *ns) /* Circuit. */ dos_num_circ_max_outq = get_param_dos_num_circ_max_outq(ns); + + /* Stream. */ + dos_stream_enabled = get_param_stream_enabled(ns); + dos_stream_defense_type = get_param_stream_defense_type(ns); + dos_stream_rate = get_param_stream_rate(ns); + dos_stream_burst = get_param_stream_burst(ns); } /* Free everything for the circuit creation DoS mitigation subsystem. */ @@ -760,6 +837,48 @@ dos_conn_addr_get_defense_type(const tor_addr_t *addr) return DOS_CONN_DEFENSE_NONE; } +/* Stream creation public API. */ + +/** Return the number of rejected stream and resolve. */ +uint64_t +dos_get_num_stream_rejected(void) +{ + return stream_num_rejected; +} + +/* Return the action to take against a BEGIN or RESOLVE cell. Return + * DOS_STREAM_DEFENSE_NONE when no action should be taken. + * Increment the appropriate counter when the cell was found to go over a + * limit. */ +dos_stream_defense_type_t +dos_stream_new_begin_or_resolve_cell(or_circuit_t *circ) +{ + if (!dos_stream_enabled || circ == NULL) + return DOS_STREAM_DEFENSE_NONE; + + token_bucket_ctr_refill(&circ->stream_limiter, + (uint32_t) monotime_coarse_absolute_sec()); + + if (token_bucket_ctr_get(&circ->stream_limiter) > 0) { + token_bucket_ctr_dec(&circ->stream_limiter, 1); + return DOS_STREAM_DEFENSE_NONE; + } + /* if defense type is DOS_STREAM_DEFENSE_NONE but DoSStreamEnabled is true, + * we count offending cells as rejected, despite them being actually + * accepted. */ + ++stream_num_rejected; + return dos_stream_defense_type; +} + +/* Initialize the token bucket for stream rate limit on a circuit. */ +void +dos_stream_init_circ_tbf(or_circuit_t *circ) +{ + token_bucket_ctr_init(&circ->stream_limiter, dos_stream_rate, + dos_stream_burst, + (uint32_t) monotime_coarse_absolute_sec()); +} + /* General API */ /* Take any appropriate actions for the given geoip entry that is about to get @@ -945,6 +1064,14 @@ dos_log_heartbeat(void) "[DoSRefuseSingleHopClientRendezvous disabled]"); } + if (dos_stream_enabled) { + smartlist_add_asprintf(elems, + "%" PRIu64 " stream rejected", + stream_num_rejected); + } else { + smartlist_add_asprintf(elems, "[DoSStreamCreationEnabled disabled]"); + } + /* HS DoS stats. */ smartlist_add_asprintf(elems, "%" PRIu64 " INTRODUCE2 rejected", |