bridges.c File Reference

Code to manage bridges and bridge selection. More...

#include "or.h"
#include "bridges.h"
#include "circuitbuild.h"
#include "config.h"
#include "connection.h"
#include "directory.h"
#include "entrynodes.h"
#include "nodelist.h"
#include "policies.h"
#include "router.h"
#include "routerlist.h"
#include "routerset.h"
#include "transports.h"

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Data Structures
struct	bridge_info_t

Macros
#define	TOR_BRIDGES_PRIVATE
#define	bridge_free(bridge)   FREE_AND_NULL(bridge_info_t, bridge_free_, (bridge))

Functions
void	mark_bridge_list (void)
void	sweep_bridge_list (void)
STATIC void	clear_bridge_list (void)
const smartlist_t *	bridge_list_get (void)
const uint8_t *	bridge_get_rsa_id_digest (const bridge_info_t *bridge)
const tor_addr_port_t *	bridge_get_addr_port (const bridge_info_t *bridge)
STATIC bridge_info_t *	get_configured_bridge_by_orports_digest (const char *digest, const smartlist_t *orports)
bridge_info_t *	get_configured_bridge_by_addr_port_digest (const tor_addr_t *addr, uint16_t port, const char *digest)
bridge_info_t *	get_configured_bridge_by_exact_addr_port_digest (const tor_addr_t *addr, uint16_t port, const char *digest)
int	addr_is_a_configured_bridge (const tor_addr_t *addr, uint16_t port, const char *digest)
int	extend_info_is_a_configured_bridge (const extend_info_t *ei)
int	routerinfo_is_a_configured_bridge (const routerinfo_t *ri)
int	node_is_a_configured_bridge (const node_t *node)
void	learned_router_identity (const tor_addr_t *addr, uint16_t port, const char *digest, const ed25519_public_key_t *ed_id)
STATIC void	bridge_resolve_conflicts (const tor_addr_t *addr, uint16_t port, const char *digest, const char *transport_name)
	MOCK_IMPL (int, transport_is_needed,(const char *transport_name))
void	bridge_add_from_config (bridge_line_t *bridge_line)
STATIC bridge_info_t *	find_bridge_by_digest (const char *digest)
const char *	find_transport_name_by_bridge_addrport (const tor_addr_t *addr, uint16_t port)
int	get_transport_by_bridge_addrport (const tor_addr_t *addr, uint16_t port, const transport_t **transport)
const smartlist_t *	get_socks_args_by_bridge_addrport (const tor_addr_t *addr, uint16_t port)
void	retry_bridge_descriptor_fetch_directly (const char *digest)
void	fetch_bridge_descriptors (const or_options_t *options, time_t now)
void	learned_bridge_descriptor (routerinfo_t *ri, int from_cache)
	MOCK_IMPL (smartlist_t *, list_bridge_identities,(void))
	MOCK_IMPL (download_status_t *, get_bridge_dl_status_by_id,(const char *digest))
void	bridges_free_all (void)

Detailed Description

Code to manage bridges and bridge selection.

Bridges are fixed entry nodes, used for censorship circumvention.

Function Documentation

addr_is_a_configured_bridge()

int addr_is_a_configured_bridge	(	const tor_addr_t *	addr,
		uint16_t	port,
		const char *	digest
	)

If we have a bridge configured whose digest matches digest, or a bridge with no known digest whose address matches addr:port, return 1. Else return 0. If digest is NULL, check for address/port matches only.

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bridge_add_from_config()

void bridge_add_from_config

(

bridge_line_t *

bridge_line

)

Register the bridge information in bridge_line to the bridge subsystem. Steals reference of bridge_line.

bridge_get_addr_port()

const tor_addr_port_t* bridge_get_addr_port

(

const bridge_info_t *

bridge

)

Given a bridge, return a pointer to its configured addr:port combination.

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bridge_get_rsa_id_digest()

const uint8_t* bridge_get_rsa_id_digest

(

const bridge_info_t *

bridge

)

Given a bridge, return a pointer to its RSA identity digest, or NULL if we don't know one for it.

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bridge_list_get()

const smartlist_t* bridge_list_get

(

void

)

Return a list of all the configured bridges, as bridge_info_t pointers.

bridge_resolve_conflicts()

STATIC void bridge_resolve_conflicts	(	const tor_addr_t *	addr,
		uint16_t	port,
		const char *	digest,
		const char *	transport_name
	)

We are about to add a new bridge at addr:port, with optional digest and transport_name. Mark for removal any previously existing bridge with the same address and port, and warn the user as appropriate.

bridges_free_all()

void bridges_free_all

(

void

)

Release all storage held in bridges.c

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clear_bridge_list()

STATIC void clear_bridge_list

(

void

)

Initialize the bridge list to empty, creating it if needed.

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extend_info_is_a_configured_bridge()

int extend_info_is_a_configured_bridge

(

const extend_info_t *

ei

)

If we have a bridge configured whose digest matches ei->identity_digest, or a bridge with no known digest whose address matches ei->addr:ei->port, return 1. Else return 0. If ei->onion_key is NULL, check for address/port matches only.

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fetch_bridge_descriptors()

void fetch_bridge_descriptors	(	const or_options_t *	options,
		time_t	now
	)

For each bridge in our list for which we don't currently have a descriptor, fetch a new copy of its descriptor – either directly from the bridge or via a bridge authority.

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find_bridge_by_digest()

STATIC bridge_info_t* find_bridge_by_digest

(

const char *

digest

)

If digest is one of our known bridges, return it.

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find_transport_name_by_bridge_addrport()

const char* find_transport_name_by_bridge_addrport	(	const tor_addr_t *	addr,
		uint16_t	port
	)

Given the addr and port of a bridge, if that bridge supports a pluggable transport, return its name. Otherwise, return NULL.

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get_configured_bridge_by_addr_port_digest()

bridge_info_t* get_configured_bridge_by_addr_port_digest	(	const tor_addr_t *	addr,
		uint16_t	port,
		const char *	digest
	)

If we have a bridge configured whose digest matches digest, or a bridge with no known digest whose address matches addr:port, return that bridge. Else return NULL. If digest is NULL, check for address/port matches only.

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get_configured_bridge_by_exact_addr_port_digest()

bridge_info_t* get_configured_bridge_by_exact_addr_port_digest	(	const tor_addr_t *	addr,
		uint16_t	port,
		const char *	digest
	)

As get_configured_bridge_by_addr_port, but require that the address match addr:port, and that the ID digest match digest. (The other function will ignore the address if the digest matches.)

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get_configured_bridge_by_orports_digest()

STATIC bridge_info_t* get_configured_bridge_by_orports_digest	(	const char *	digest,
		const smartlist_t *	orports
	)

If we have a bridge configured whose digest matches digest, or a bridge with no known digest whose address matches any of the tor_addr_port_t's in orports, return that bridge. Else return NULL.

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get_socks_args_by_bridge_addrport()

const smartlist_t* get_socks_args_by_bridge_addrport	(	const tor_addr_t *	addr,
		uint16_t	port
	)

Return a smartlist containing all the SOCKS arguments that we should pass to the SOCKS proxy.

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get_transport_by_bridge_addrport()

int get_transport_by_bridge_addrport	(	const tor_addr_t *	addr,
		uint16_t	port,
		const transport_t **	transport
	)

If addr and port match the address and port of a bridge of ours that uses pluggable transports, place its transport in transport.

Return 0 on success (found a transport, or found a bridge with no transport, or found no bridge); return -1 if we should be using a transport, but the transport could not be found.

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learned_bridge_descriptor()

void learned_bridge_descriptor	(	routerinfo_t *	ri,
		int	from_cache
	)

We just learned a descriptor for a bridge. See if that digest is in our entry guard list, and add it if not.

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learned_router_identity()

void learned_router_identity	(	const tor_addr_t *	addr,
		uint16_t	port,
		const char *	digest,
		const ed25519_public_key_t *	ed_id
	)

We made a connection to a router at addr:port without knowing its digest. Its digest turned out to be digest. If it was a bridge, and we still don't know its digest, record it.

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mark_bridge_list()

void mark_bridge_list

(

void

)

Mark every entry of the bridge list to be removed on our next call to sweep_bridge_list unless it has first been un-marked.

MOCK_IMPL() [1/3]

MOCK_IMPL	(	int	,
		transport_is_needed	,
		(const char *transport_name)
	)

Return True if we have a bridge that uses a transport with name transport_name.

MOCK_IMPL() [2/3]

MOCK_IMPL	(	smartlist_t *	,
		list_bridge_identities	,
		(void)
	)

Return a smartlist containing all bridge identity digests

MOCK_IMPL() [3/3]

MOCK_IMPL	(	download_status_t *	,
		get_bridge_dl_status_by_id	,
		(const char *digest)
	)

Get the download status for a bridge descriptor given its identity

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node_is_a_configured_bridge()

int node_is_a_configured_bridge

(

const node_t *

node

)

Return 1 if node is one of our configured bridges, else 0.

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retry_bridge_descriptor_fetch_directly()

void retry_bridge_descriptor_fetch_directly

(

const char *

digest

)

Fetching the bridge descriptor from the bridge authority returned a "not found". Fall back to trying a direct fetch.

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routerinfo_is_a_configured_bridge()

int routerinfo_is_a_configured_bridge

(

const routerinfo_t *

ri

)

Return 1 if ri is one of our known bridges, else 0.

sweep_bridge_list()

void sweep_bridge_list

(

void

)

Remove every entry of the bridge list that was marked with mark_bridge_list if it has not subsequently been un-marked.