141 lines
5.0 KiB
C
141 lines
5.0 KiB
C
/* Copyright (c) 2018, The Tor Project, Inc. */
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/* See LICENSE for licensing information */
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/*
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* \file dos.h
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* \brief Header file for dos.c
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*/
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#ifndef TOR_DOS_H
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#define TOR_DOS_H
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/* Structure that keeps stats of client connection per-IP. */
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typedef struct cc_client_stats_t {
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/* Number of allocated circuits remaining for this address. It is
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* decremented every time a new circuit is seen for this client address and
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* if the count goes to 0, we have a positive detection. */
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uint32_t circuit_bucket;
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/* When was the last time we've refilled the circuit bucket? This is used to
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* know if we need to refill the bucket when a new circuit is seen. It is
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* synchronized using approx_time(). */
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time_t last_circ_bucket_refill_ts;
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/* This client address was detected to be above the circuit creation rate
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* and this timestamp indicates until when it should remain marked as
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* detected so we can apply a defense for the address. It is synchronized
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* using the approx_time(). */
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time_t marked_until_ts;
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} cc_client_stats_t;
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/* This object is a top level object that contains everything related to the
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* per-IP client DoS mitigation. Because it is per-IP, it is used in the geoip
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* clientmap_entry_t object. */
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typedef struct dos_client_stats_t {
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/* Concurrent connection count from the specific address. 2^32 is most
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* likely way too big for the amount of allowed file descriptors. */
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uint32_t concurrent_count;
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/* Circuit creation statistics. This is only used if the circuit creation
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* subsystem has been enabled (dos_cc_enabled). */
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cc_client_stats_t cc_stats;
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} dos_client_stats_t;
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/* General API. */
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/* Stub. */
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struct clientmap_entry_t;
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void dos_init(void);
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void dos_free_all(void);
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void dos_consensus_has_changed(const networkstatus_t *ns);
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int dos_enabled(void);
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void dos_log_heartbeat(void);
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void dos_geoip_entry_about_to_free(const struct clientmap_entry_t *geoip_ent);
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void dos_new_client_conn(or_connection_t *or_conn);
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void dos_close_client_conn(const or_connection_t *or_conn);
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int dos_should_refuse_single_hop_client(void);
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void dos_note_refuse_single_hop_client(void);
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/*
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* Circuit creation DoS mitigation subsystemn interface.
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*/
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/* DoSCircuitCreationEnabled default. Disabled by default. */
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#define DOS_CC_ENABLED_DEFAULT 0
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/* DoSCircuitCreationDefenseType maps to the dos_cc_defense_type_t enum. */
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#define DOS_CC_DEFENSE_TYPE_DEFAULT DOS_CC_DEFENSE_REFUSE_CELL
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/* DoSCircuitCreationMinConnections default */
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#define DOS_CC_MIN_CONCURRENT_CONN_DEFAULT 3
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/* DoSCircuitCreationRateTenths is 3 per seconds. */
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#define DOS_CC_CIRCUIT_RATE_DEFAULT 3
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/* DoSCircuitCreationBurst default. */
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#define DOS_CC_CIRCUIT_BURST_DEFAULT 90
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/* DoSCircuitCreationDefenseTimePeriod in seconds. */
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#define DOS_CC_DEFENSE_TIME_PERIOD_DEFAULT (60 * 60)
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/* Type of defense that we can use for the circuit creation DoS mitigation. */
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typedef enum dos_cc_defense_type_t {
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/* No defense used. */
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DOS_CC_DEFENSE_NONE = 1,
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/* Refuse any cells which means a DESTROY cell will be sent back. */
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DOS_CC_DEFENSE_REFUSE_CELL = 2,
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/* Maximum value that can be used. Useful for the boundaries of the
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* consensus parameter. */
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DOS_CC_DEFENSE_MAX = 2,
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} dos_cc_defense_type_t;
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void dos_cc_new_create_cell(channel_t *channel);
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dos_cc_defense_type_t dos_cc_get_defense_type(channel_t *chan);
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/*
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* Concurrent connection DoS mitigation interface.
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*/
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/* DoSConnectionEnabled default. Disabled by default. */
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#define DOS_CONN_ENABLED_DEFAULT 0
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/* DoSConnectionMaxConcurrentCount default. */
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#define DOS_CONN_MAX_CONCURRENT_COUNT_DEFAULT 100
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/* DoSConnectionDefenseType maps to the dos_conn_defense_type_t enum. */
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#define DOS_CONN_DEFENSE_TYPE_DEFAULT DOS_CONN_DEFENSE_CLOSE
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/* Type of defense that we can use for the concurrent connection DoS
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* mitigation. */
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typedef enum dos_conn_defense_type_t {
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/* No defense used. */
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DOS_CONN_DEFENSE_NONE = 1,
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/* Close immediately the connection meaning refuse it. */
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DOS_CONN_DEFENSE_CLOSE = 2,
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/* Maximum value that can be used. Useful for the boundaries of the
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* consensus parameter. */
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DOS_CONN_DEFENSE_MAX = 2,
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} dos_conn_defense_type_t;
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dos_conn_defense_type_t dos_conn_addr_get_defense_type(const tor_addr_t *addr);
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#ifdef DOS_PRIVATE
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STATIC uint32_t get_param_conn_max_concurrent_count(
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const networkstatus_t *ns);
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STATIC uint32_t get_param_cc_circuit_burst(const networkstatus_t *ns);
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STATIC uint32_t get_param_cc_min_concurrent_connection(
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const networkstatus_t *ns);
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STATIC uint64_t get_circuit_rate_per_second(void);
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STATIC void cc_stats_refill_bucket(cc_client_stats_t *stats,
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const tor_addr_t *addr);
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MOCK_DECL(STATIC unsigned int, get_param_cc_enabled,
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(const networkstatus_t *ns));
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MOCK_DECL(STATIC unsigned int, get_param_conn_enabled,
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(const networkstatus_t *ns));
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#endif /* TOR_DOS_PRIVATE */
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#endif /* TOR_DOS_H */
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