hs_dos.c File Reference

Implement denial of service mitigation for the onion service subsystem. More...

#include "core/or/or.h"
#include "app/config/config.h"
#include "core/or/circuitlist.h"
#include "feature/hs/hs_circuitmap.h"
#include "feature/nodelist/networkstatus.h"
#include "feature/relay/routermode.h"
#include "lib/evloop/token_bucket.h"
#include "feature/hs/hs_dos.h"

Go to the source code of this file.

Macros
#define	HS_DOS_PRIVATE
#define	HS_DOS_INTRODUCE_DEFAULT_CELL_RATE_PER_SEC   25
#define	HS_DOS_INTRODUCE_DEFAULT_CELL_BURST_PER_SEC   200
#define	HS_DOS_INTRODUCE_ENABLED_DEFAULT   0

Functions
STATIC uint32_t	get_intro2_enable_consensus_param (const networkstatus_t *ns)
STATIC uint32_t	get_intro2_rate_consensus_param (const networkstatus_t *ns)
STATIC uint32_t	get_intro2_burst_consensus_param (const networkstatus_t *ns)
static void	update_intro_circuits (void)
static void	set_consensus_parameters (const networkstatus_t *ns)
void	hs_dos_setup_default_intro2_defenses (or_circuit_t *circ)
void	hs_dos_consensus_has_changed (const networkstatus_t *ns)
bool	hs_dos_can_send_intro2 (or_circuit_t *s_intro_circ)
uint64_t	hs_dos_get_intro2_rejected_count (void)
void	hs_dos_init (void)

Variables
static uint64_t	intro2_rejected_count = 0
static uint32_t	consensus_param_introduce_rate_per_sec
static uint32_t	consensus_param_introduce_burst_per_sec
static uint32_t	consensus_param_introduce_defense_enabled

Detailed Description

Implement denial of service mitigation for the onion service subsystem.

This module defenses:

• Introduction Rate Limiting: If enabled by the consensus, an introduction point will rate limit client introduction towards the service (INTRODUCE2 cells). It uses a token bucket model with a rate and burst per second.

  Proposal 305 will expand this module by allowing an operator to define these values into the ESTABLISH_INTRO cell. Not yet implemented.

Definition in file hs_dos.c.

Macro Definition Documentation

HS_DOS_INTRODUCE_DEFAULT_CELL_BURST_PER_SEC

#define HS_DOS_INTRODUCE_DEFAULT_CELL_BURST_PER_SEC   200

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.

Definition at line 42 of file hs_dos.c.

HS_DOS_INTRODUCE_DEFAULT_CELL_RATE_PER_SEC

#define HS_DOS_INTRODUCE_DEFAULT_CELL_RATE_PER_SEC   25

Default value of the allowed INTRODUCE2 cell rate per second. Above that value per second, the introduction is denied.

Definition at line 36 of file hs_dos.c.

HS_DOS_INTRODUCE_ENABLED_DEFAULT

#define HS_DOS_INTRODUCE_ENABLED_DEFAULT   0

Default value of the consensus parameter enabling or disabling the introduction DoS defense. Disabled by default.

Definition at line 46 of file hs_dos.c.

Function Documentation

get_intro2_burst_consensus_param()

STATIC uint32_t get_intro2_burst_consensus_param

(

const networkstatus_t *

ns

)

Return the parameter for the introduction burst per sec.

Definition at line 79 of file hs_dos.c.

get_intro2_rate_consensus_param()

STATIC uint32_t get_intro2_rate_consensus_param

(

const networkstatus_t *

ns

)

Return the parameter for the introduction rate per sec.

Definition at line 70 of file hs_dos.c.

hs_dos_can_send_intro2()

bool hs_dos_can_send_intro2

(

or_circuit_t *

s_intro_circ

)

Return true iff an INTRODUCE2 cell can be sent on the given service introduction circuit.

Definition at line 166 of file hs_dos.c.

hs_dos_consensus_has_changed()

void hs_dos_consensus_has_changed

(

const networkstatus_t *

ns

)

Called when the consensus has changed. We might have new consensus parameters to look at.

Definition at line 152 of file hs_dos.c.

hs_dos_get_intro2_rejected_count()

uint64_t hs_dos_get_intro2_rejected_count

(

void

)

Return rolling count of rejected INTRO2.

Definition at line 218 of file hs_dos.c.

hs_dos_init()

void hs_dos_init

(

void

)

Initialize the onion service Denial of Service subsystem.

Definition at line 225 of file hs_dos.c.

hs_dos_setup_default_intro2_defenses()

void hs_dos_setup_default_intro2_defenses

(

or_circuit_t *

circ

)

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.

Definition at line 137 of file hs_dos.c.

set_consensus_parameters()

static void set_consensus_parameters ( const networkstatus_t *  ns )

static

Set consensus parameters.

Definition at line 115 of file hs_dos.c.

Referenced by hs_dos_consensus_has_changed(), and hs_dos_init().

update_intro_circuits()

static void update_intro_circuits ( void  )

static

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.

Definition at line 90 of file hs_dos.c.

Variable Documentation

consensus_param_introduce_burst_per_sec

uint32_t consensus_param_introduce_burst_per_sec

static

Initial value:

=
  HS_DOS_INTRODUCE_DEFAULT_CELL_BURST_PER_SEC

Definition at line 56 of file hs_dos.c.

consensus_param_introduce_defense_enabled

uint32_t consensus_param_introduce_defense_enabled

static

Initial value:

=
  HS_DOS_INTRODUCE_ENABLED_DEFAULT

Definition at line 58 of file hs_dos.c.

consensus_param_introduce_rate_per_sec

uint32_t consensus_param_introduce_rate_per_sec

static

Initial value:

=
  HS_DOS_INTRODUCE_DEFAULT_CELL_RATE_PER_SEC

Definition at line 54 of file hs_dos.c.

intro2_rejected_count

uint64_t intro2_rejected_count = 0

static

INTRODUCE2 rejected request counter.

Definition at line 49 of file hs_dos.c.

Referenced by hs_dos_get_intro2_rejected_count().