microdesc.c File Reference

Implements microdescriptors – an abbreviated description of less-frequently-changing router information. More...

#include "core/or/or.h"
#include "lib/fdio/fdio.h"
#include "app/config/config.h"
#include "core/or/circuitbuild.h"
#include "core/or/policies.h"
#include "feature/client/entrynodes.h"
#include "feature/dircache/dirserv.h"
#include "feature/dirclient/dlstatus.h"
#include "feature/dirclient/dirclient_modes.h"
#include "feature/dircommon/directory.h"
#include "feature/dirparse/microdesc_parse.h"
#include "feature/nodelist/dirlist.h"
#include "feature/nodelist/microdesc.h"
#include "feature/nodelist/networkstatus.h"
#include "feature/nodelist/nodefamily.h"
#include "feature/nodelist/nodelist.h"
#include "feature/nodelist/routerlist.h"
#include "feature/relay/router.h"
#include "feature/nodelist/microdesc_st.h"
#include "feature/nodelist/networkstatus_st.h"
#include "feature/nodelist/node_st.h"
#include "feature/nodelist/routerstatus_st.h"

Go to the source code of this file.

Data Structures
struct	microdesc_cache_t

Macros
#define	TOO_MANY_OUTDATED_DIRSERVERS   30
#define	TOLERATE_MICRODESC_AGE   (7*24*60*60)

Functions
static microdesc_cache_t *	get_microdesc_cache_noload (void)
static void	warn_if_nul_found (const char *inp, size_t len, int64_t offset, const char *activity)
static unsigned int	microdesc_hash_ (microdesc_t *md)
static int	microdesc_eq_ (microdesc_t *a, microdesc_t *b)
	HT_PROTOTYPE (microdesc_map, microdesc_t, node, microdesc_hash_, microdesc_eq_)
	HT_GENERATE2 (microdesc_map, microdesc_t, node, microdesc_hash_, microdesc_eq_, 0.6, tor_reallocarray_, tor_free_)
void	microdesc_note_outdated_dirserver (const char *relay_digest)
int	microdesc_relay_is_outdated_dirserver (const char *relay_digest)
void	microdesc_reset_outdated_dirservers_list (void)
static ssize_t	dump_microdescriptor (int fd, microdesc_t *md, size_t *annotation_len_out)
microdesc_cache_t *	get_microdesc_cache (void)
smartlist_t *	microdescs_add_to_cache (microdesc_cache_t *cache, const char *s, const char *eos, saved_location_t where, int no_save, time_t listed_at, smartlist_t *requested_digests256)
smartlist_t *	microdescs_add_list_to_cache (microdesc_cache_t *cache, smartlist_t *descriptors, saved_location_t where, int no_save)
void	microdesc_cache_clear (microdesc_cache_t *cache)
int	microdesc_cache_reload (microdesc_cache_t *cache)
void	microdesc_cache_clean (microdesc_cache_t *cache, time_t cutoff, int force)
static int	should_rebuild_md_cache (microdesc_cache_t *cache)
static void	microdesc_wipe_body (microdesc_t *md)
int	microdesc_cache_rebuild (microdesc_cache_t *cache, int force)
void	microdesc_check_counts (void)
void	microdesc_free_ (microdesc_t *md, const char *fname, int lineno)
void	microdesc_free_all (void)
microdesc_t *	microdesc_cache_lookup_by_digest256 (microdesc_cache_t *cache, const char *d)
smartlist_t *	microdesc_list_missing_digest256 (networkstatus_t *ns, microdesc_cache_t *cache, int downloadable_only, digest256map_t *skip)
void	update_microdesc_downloads (time_t now)
void	update_microdescs_from_networkstatus (time_t now)
int	we_use_microdescriptors_for_circuits (const or_options_t *options)
int	we_fetch_microdescriptors (const or_options_t *options)
int	we_fetch_router_descriptors (const or_options_t *options)
int	usable_consensus_flavor (void)

Variables
static smartlist_t *	outdated_dirserver_list = NULL
static microdesc_cache_t *	the_microdesc_cache = NULL

Detailed Description

Implements microdescriptors – an abbreviated description of less-frequently-changing router information.

Definition in file microdesc.c.

Macro Definition Documentation

TOLERATE_MICRODESC_AGE

#define TOLERATE_MICRODESC_AGE   (7*24*60*60)

By default, we remove any microdescriptors that have gone at least this long without appearing in a current consensus.

Definition at line 563 of file microdesc.c.

Function Documentation

dump_microdescriptor()

static ssize_t dump_microdescriptor ( int  fd, microdesc_t *  md, size_t *  annotation_len_out  )

static

Write the body of md into f, with appropriate annotations. On success, return the total number of bytes written, and set *annotation_len_out to the number of bytes written as annotations.

Definition at line 203 of file microdesc.c.

get_microdesc_cache()

microdesc_cache_t* get_microdesc_cache

(

void

)

Return a pointer to the microdescriptor cache, loading it if necessary.

Definition at line 251 of file microdesc.c.

Referenced by microdesc_cache_lookup_by_digest256(), and update_microdescs_from_networkstatus().

get_microdesc_cache_noload()

static microdesc_cache_t * get_microdesc_cache_noload ( void  )

static

Return a pointer to the microdescriptor cache, creating (but not loading) it if necessary.

Definition at line 263 of file microdesc.c.

Referenced by get_microdesc_cache(), and microdesc_free_().

microdesc_cache_clean()

void microdesc_cache_clean	(	microdesc_cache_t *	cache,
		time_t	cutoff,
		int	force
	)

Remove all microdescriptors from cache that haven't been listed for a long time. Does not rebuild the cache on disk. If cutoff is positive, specifically remove microdescriptors that have been unlisted since cutoff. If force is true, remove microdescriptors even if we have no current live microdescriptor consensus.

Definition at line 572 of file microdesc.c.

Referenced by microdesc_cache_rebuild().

microdesc_cache_clear()

void microdesc_cache_clear

(

microdesc_cache_t *

cache

)

Remove every microdescriptor in cache.

Definition at line 465 of file microdesc.c.

Referenced by microdesc_cache_reload(), and microdesc_free_all().

microdesc_cache_lookup_by_digest256()

microdesc_t* microdesc_cache_lookup_by_digest256	(	microdesc_cache_t *	cache,
		const char *	d
	)

If there is a microdescriptor in cache whose sha256 digest is d, return it. Otherwise return NULL.

Definition at line 946 of file microdesc.c.

microdesc_cache_rebuild()

int microdesc_cache_rebuild	(	microdesc_cache_t *	cache,
		int	force
	)

Regenerate the main cache file for cache, clear the journal file, and update every microdesc_t in the cache with pointers to its new location. If force is true, do this unconditionally. If force is false, do it only if we expect to save space on disk.

Definition at line 705 of file microdesc.c.

Referenced by clean_caches_callback().

microdesc_cache_reload()

int microdesc_cache_reload

(

microdesc_cache_t *

cache

)

Reload the contents of cache from disk. If it is empty, load it for the first time. Return 0 on success, -1 on failure.

Definition at line 515 of file microdesc.c.

microdesc_check_counts()

void microdesc_check_counts

(

void

)

Make sure that the reference count of every microdescriptor in cache is accurate.

Definition at line 844 of file microdesc.c.

microdesc_eq_()

static int microdesc_eq_ ( microdesc_t *  a, microdesc_t *  b  )

inlinestatic

Helper: compares a and b for equality for hash-table purposes.

Definition at line 87 of file microdesc.c.

microdesc_free_()

void microdesc_free_	(	microdesc_t *	md,
		const char *	fname,
		int	lineno
	)

Deallocate a single microdescriptor. Note: the microdescriptor MUST have previously been removed from the cache if it had ever been inserted.

Definition at line 866 of file microdesc.c.

microdesc_free_all()

void microdesc_free_all

(

void

)

Free all storage held in the microdesc.c module.

Definition at line 928 of file microdesc.c.

microdesc_hash_()

static unsigned int microdesc_hash_ ( microdesc_t *  md )

inlinestatic

Helper: computes a hash of md to place it in a hash table.

Definition at line 79 of file microdesc.c.

microdesc_list_missing_digest256()

smartlist_t* microdesc_list_missing_digest256	(	networkstatus_t *	ns,
		microdesc_cache_t *	cache,
		int	downloadable_only,
		digest256map_t *	skip
	)

Return a smartlist of all the sha256 digest of the microdescriptors that are listed in ns but not present in cache. Returns pointers to internals of ns; you should not free the members of the resulting smartlist. Omit all microdescriptors whose digest appear in skip.

Definition at line 961 of file microdesc.c.

microdesc_note_outdated_dirserver()

void microdesc_note_outdated_dirserver

(

const char *

relay_digest

)

Note that we failed to fetch a microdescriptor from the relay with relay_digest (of size DIGEST_LEN).

Definition at line 111 of file microdesc.c.

microdesc_relay_is_outdated_dirserver()

int microdesc_relay_is_outdated_dirserver

(

const char *

relay_digest

)

Return True if the relay with relay_digest (size DIGEST_LEN) is an outdated dirserver

Definition at line 163 of file microdesc.c.

Referenced by guard_obeys_md_dirserver_restriction().

microdesc_reset_outdated_dirservers_list()

void microdesc_reset_outdated_dirservers_list

(

void

)

Reset the list of outdated dirservers.

Definition at line 186 of file microdesc.c.

microdesc_wipe_body()

static void microdesc_wipe_body ( microdesc_t *  md )

static

Mark md as having no body, and release any storage previously held by its body.

Definition at line 685 of file microdesc.c.

microdescs_add_list_to_cache()

smartlist_t* microdescs_add_list_to_cache	(	microdesc_cache_t *	cache,
		smartlist_t *	descriptors,
		saved_location_t	where,
		int	no_save
	)

As microdescs_add_to_cache, but takes a list of microdescriptors instead of a string to decode. Frees any members of descriptors that it does not add.

Definition at line 383 of file microdesc.c.

microdescs_add_to_cache()

smartlist_t* microdescs_add_to_cache	(	microdesc_cache_t *	cache,
		const char *	s,
		const char *	eos,
		saved_location_t	where,
		int	no_save,
		time_t	listed_at,
		smartlist_t *	requested_digests256
	)

Decode the microdescriptors from the string starting at s and ending at eos, and store them in cache. If no_save, mark them as non-writable to disk. If where is SAVED_IN_CACHE, leave their bodies as pointers to the mmap'd cache. If where is SAVED_NOWHERE, do not allow annotations. If listed_at is not -1, set the last_listed field of every microdesc to listed_at. If requested_digests is non-null, then it contains a list of digests we mean to allow, so we should reject any non-requested microdesc with a different digest, and alter the list to contain only the digests of those microdescs we didn't find. Return a newly allocated list of the added microdescriptors, or NULL

Definition at line 293 of file microdesc.c.

update_microdesc_downloads()

void update_microdesc_downloads

(

time_t

now

)

Launch download requests for microdescriptors as appropriate.

Specifically, we should launch download requests if we are configured to download mirodescriptors, and there are some microdescriptors listed in the current microdesc consensus that we don't have, and either we never asked for them, or we failed to download them but we're willing to retry.

Definition at line 993 of file microdesc.c.

Referenced by update_all_descriptor_downloads().

update_microdescs_from_networkstatus()

void update_microdescs_from_networkstatus

(

time_t

now

)

For every microdescriptor listed in the current microdescriptor consensus, update its last_listed field to be at least as recent as the publication time of the current microdescriptor consensus.

Definition at line 1033 of file microdesc.c.

usable_consensus_flavor()

int usable_consensus_flavor

(

void

)

Return the consensus flavor we actually want to use to build circuits.

Definition at line 1086 of file microdesc.c.

Referenced by cached_client_descriptor_has_expired(), consensus_is_waiting_for_certs(), count_loading_descriptors_progress(), get_voting_interval(), hs_get_responsible_hsdirs(), hs_get_time_period_num(), hs_in_period_between_tp_and_srv(), networkstatus_consensus_is_bootstrapping(), reasonably_live_consensus_is_missing(), should_rotate_descriptors(), sr_get_current(), sr_get_previous(), update_consensus_bootstrap_attempt_downloads(), update_consensus_bootstrap_multiple_downloads(), update_consensus_networkstatus_downloads(), and update_router_have_minimum_dir_info().

we_fetch_microdescriptors()

int we_fetch_microdescriptors

(

const or_options_t *

options

)

Return true iff we should try to download microdescriptors at all.

Definition at line 1064 of file microdesc.c.

we_fetch_router_descriptors()

int we_fetch_router_descriptors

(

const or_options_t *

options

)

Return true iff we should try to download router descriptors at all.

Definition at line 1075 of file microdesc.c.

Referenced by update_router_descriptor_downloads().

we_use_microdescriptors_for_circuits()

int we_use_microdescriptors_for_circuits

(

const or_options_t *

options

)

Return true iff we should prefer to use microdescriptors rather than routerdescs for building circuits.

Definition at line 1055 of file microdesc.c.

Referenced by networkstatus_get_latest_consensus(), node_has_preferred_descriptor(), usable_consensus_flavor(), we_fetch_microdescriptors(), and we_fetch_router_descriptors().

Variable Documentation

outdated_dirserver_list

smartlist_t* outdated_dirserver_list = NULL

static

List of dirservers with outdated microdesc information. The smartlist is filled with the hex digests of outdated dirservers.

Definition at line 106 of file microdesc.c.

Referenced by microdesc_free_all(), microdesc_relay_is_outdated_dirserver(), and microdesc_reset_outdated_dirservers_list().

the_microdesc_cache

microdesc_cache_t* the_microdesc_cache = NULL

static

Holds a pointer to the current microdesc_cache_t object, or NULL if no such object has been allocated.

Definition at line 247 of file microdesc.c.

Referenced by microdesc_cache_rebuild(), microdesc_check_counts(), and microdesc_free_all().