addressmap.c File Reference

The addressmap module manages the processes by which we rewrite addresses in client requess. It handles the MapAddress controller and torrc commands, and the TrackHostExits feature, and the client-side DNS cache (deprecated). More...

#include "or.h"
#include "addressmap.h"
#include "circuituse.h"
#include "config.h"
#include "connection_edge.h"
#include "control.h"
#include "crypto_rand.h"
#include "dns.h"
#include "nodelist.h"
#include "routerset.h"

Include dependency graph for addressmap.c:

Data Structures
struct	addressmap_entry_t
struct	virtaddress_entry_t

Macros
#define	ADDRESSMAP_PRIVATE
#define	addressmap_ent_free(ent)   FREE_AND_NULL(addressmap_entry_t, addressmap_ent_free_, (ent))
#define	addressmap_virtaddress_ent_free(ent)   FREE_AND_NULL(virtaddress_entry_t, addressmap_virtaddress_ent_free_, (ent))

Functions
void	addressmap_init (void)
void	clear_trackexithost_mappings (const char *exitname)
void	addressmap_clear_excluded_trackexithosts (const or_options_t *options)
int	addressmap_address_should_automap (const char *address, const or_options_t *options)
void	addressmap_clear_invalid_automaps (const or_options_t *options)
void	addressmap_clear_configured (void)
void	addressmap_clear_transient (void)
void	addressmap_clean (time_t now)
void	addressmap_free_all (void)
int	addressmap_rewrite (char *address, size_t maxlen, unsigned flags, time_t *expires_out, addressmap_entry_source_t *exit_source_out)
int	addressmap_rewrite_reverse (char *address, size_t maxlen, unsigned flags, time_t *expires_out)
int	addressmap_have_mapping (const char *address, int update_expiry)
void	addressmap_register (const char *address, char *new_address, time_t expires, addressmap_entry_source_t source, const int wildcard_addr, const int wildcard_new_addr)
int	client_dns_incr_failures (const char *address)
void	client_dns_clear_failures (const char *address)
void	client_dns_set_addressmap (entry_connection_t *for_conn, const char *address, const tor_addr_t *val, const char *exitname, int ttl)
void	client_dns_set_reverse_addressmap (entry_connection_t *for_conn, const char *address, const char *v, const char *exitname, int ttl)
int	parse_virtual_addr_network (const char *val, sa_family_t family, int validate_only, char **msg)
int	address_is_in_virtual_range (const char *address)
STATIC void	get_random_virtual_addr (const virtual_addr_conf_t *conf, tor_addr_t *addr_out)
const char *	addressmap_register_virtual_address (int type, char *new_address)
int	address_is_invalid_destination (const char *address, int client)
void	addressmap_get_mappings (smartlist_t *sl, time_t min_expires, time_t max_expires, int want_expiry)

Detailed Description

The addressmap module manages the processes by which we rewrite addresses in client requess. It handles the MapAddress controller and torrc commands, and the TrackHostExits feature, and the client-side DNS cache (deprecated).

Function Documentation

address_is_in_virtual_range()

int address_is_in_virtual_range

(

const char *

address

)

Return true iff addr is likely to have been returned by client_dns_get_unused_address.

Here is the call graph for this function:

address_is_invalid_destination()

int address_is_invalid_destination	(	const char *	address,
		int	client
	)

Return 1 if address has funny characters in it like colons. Return 0 if it's fine, or if we're configured to allow it anyway. client should be true if we're using this address as a client; false if we're using it as a server.

Here is the call graph for this function:

Here is the caller graph for this function:

addressmap_address_should_automap()

int addressmap_address_should_automap	(	const char *	address,
		const or_options_t *	options
	)

Return true iff address is one that we are configured to automap on resolve according to options.

Here is the call graph for this function:

addressmap_clean()

void addressmap_clean

(

time_t

now

)

Clean out entries from the addressmap cache that were added long enough ago that they are no longer valid.

Here is the call graph for this function:

Here is the caller graph for this function:

addressmap_clear_configured()

void addressmap_clear_configured

(

void

)

Remove all entries from the addressmap that were set via the configuration file or the command line.

Here is the call graph for this function:

Here is the caller graph for this function:

addressmap_clear_excluded_trackexithosts()

void addressmap_clear_excluded_trackexithosts

(

const or_options_t *

options

)

Remove all TRACKEXIT mappings from the addressmap for which the target host is unknown or no longer allowed, or for which the source address is no longer in trackexithosts.

addressmap_clear_invalid_automaps()

void addressmap_clear_invalid_automaps

(

const or_options_t *

options

)

Remove all AUTOMAP mappings from the addressmap for which the source address no longer matches AutomapHostsSuffixes, which is no longer allowed by AutomapHostsOnResolve, or for which the target address is no longer in the virtual network.

addressmap_clear_transient()

void addressmap_clear_transient

(

void

)

Remove all entries from the addressmap that are set to expire, ever.

Here is the call graph for this function:

addressmap_free_all()

void addressmap_free_all

(

void

)

Free all the elements in the addressmap, and free the addressmap itself.

addressmap_get_mappings()

void addressmap_get_mappings	(	smartlist_t *	sl,
		time_t	min_expires,
		time_t	max_expires,
		int	want_expiry
	)

Iterate over all address mappings which have expiry times between min_expires and max_expires, inclusive. If sl is provided, add an "old-addr new-addr expiry" string to sl for each mapping, omitting the expiry time if want_expiry is false. If sl is NULL, remove the mappings.

Here is the caller graph for this function:

addressmap_have_mapping()

int addressmap_have_mapping	(	const char *	address,
		int	update_expiry
	)

Return 1 if address is already registered, else return 0. If address is already registered, and update_expires is non-zero, then update the expiry time on the mapping with update_expires if it is a mapping created by TrackHostExits.

Here is the call graph for this function:

addressmap_init()

void addressmap_init

(

void

)

Initialize addressmap.

addressmap_register()

void addressmap_register	(	const char *	address,
		char *	new_address,
		time_t	expires,
		addressmap_entry_source_t	source,
		const int	wildcard_addr,
		const int	wildcard_new_addr
	)

Register a request to map address to new_address, which will expire on expires (or 0 if never expires from config file, 1 if never expires from controller, 2 if never expires (virtual address mapping) from the controller.)

new_address should be a newly dup'ed string, which we'll use or free as appropriate. We will leave address alone.

If wildcard_addr is true, then the mapping will match any address equal to address, or any address ending with a period followed by address. If wildcard_addr and wildcard_new_addr are both true, the mapping will rewrite addresses that end with ".<b>address</b>" into ones that end with ".<b>new_address</b>".

If new_address is NULL, or new_address is equal to address and wildcard_addr is equal to wildcard_new_addr, remove any mappings that exist from address.

It is an error to set wildcard_new_addr if wildcard_addr is not set.

Here is the caller graph for this function:

addressmap_register_virtual_address()

const char* addressmap_register_virtual_address	(	int	type,
		char *	new_address
	)

A controller has requested that we map some address of type type to the address new_address. Choose an address that is unlikely to be used, and map it, and return it in a newly allocated string. If another address of the same type is already mapped to new_address, try to return a copy of that address.

The string in new_address may be freed or inserted into a map as appropriate. May return NULL if are out of virtual addresses.

addressmap_rewrite()

int addressmap_rewrite	(	char *	address,
		size_t	maxlen,
		unsigned	flags,
		time_t *	expires_out,
		addressmap_entry_source_t *	exit_source_out
	)

Look at address, and rewrite it until it doesn't want any more rewrites; but don't get into an infinite loop. Don't write more than maxlen chars into address. Return true if the address changed; false otherwise. Set *expires_out to the expiry time of the result, or to time_max if the result does not expire.

If exit_source_out is non-null, we set it as follows. If we the address starts out as a non-exit address, and we remap it to an .exit address at any point, then set *exit_source_out to the address_entry_source_t of the first such rule. Set *exit_source_out to ADDRMAPSRC_NONE if there is no such rewrite, or if the original address was a .exit.

addressmap_rewrite_reverse()

int addressmap_rewrite_reverse	(	char *	address,
		size_t	maxlen,
		unsigned	flags,
		time_t *	expires_out
	)

If we have a cached reverse DNS entry for the address stored in the maxlen-byte buffer address (typically, a dotted quad) then rewrite to the cached value and return 1. Otherwise return 0. Set *expires_out to the expiry time of the result, or to time_max if the result does not expire.

Here is the call graph for this function:

clear_trackexithost_mappings()

void clear_trackexithost_mappings

(

const char *

exitname

)

Unregister all TrackHostExits mappings from any address to *.exitname.exit.

client_dns_clear_failures()

void client_dns_clear_failures

(

const char *

address

)

If address is in the client DNS addressmap, reset the number of resolve failures we have on record for it. This is used when we fail a stream because it won't resolve: otherwise future attempts on that address will only try once.

client_dns_incr_failures()

int client_dns_incr_failures

(

const char *

address

)

An attempt to resolve address failed at some OR. Increment the number of resolve failures we have on record for it, and then return that number.

client_dns_set_addressmap()

void client_dns_set_addressmap	(	entry_connection_t *	for_conn,
		const char *	address,
		const tor_addr_t *	val,
		const char *	exitname,
		int	ttl
	)

Record the fact that address resolved to val. We can now use this in subsequent streams via addressmap_rewrite() so we can more correctly choose an exit that will allow address.

If exitname is defined, then append the addresses with ".exitname.exit" before registering the mapping.

If ttl is nonnegative, the mapping will be valid for ttlseconds; otherwise, we use the default.

Here is the call graph for this function:

client_dns_set_reverse_addressmap()

void client_dns_set_reverse_addressmap	(	entry_connection_t *	for_conn,
		const char *	address,
		const char *	v,
		const char *	exitname,
		int	ttl
	)

Add a cache entry noting that address (ordinarily a dotted quad) resolved via a RESOLVE_PTR request to the hostname v.

If exitname is defined, then append the addresses with ".exitname.exit" before registering the mapping.

If ttl is nonnegative, the mapping will be valid for ttlseconds; otherwise, we use the default.

Here is the call graph for this function:

get_random_virtual_addr()

STATIC void get_random_virtual_addr	(	const virtual_addr_conf_t *	conf,
		tor_addr_t *	addr_out
	)

Return a random address conforming to the virtual address configuration in conf.

parse_virtual_addr_network()

int parse_virtual_addr_network	(	const char *	val,
		sa_family_t	family,
		int	validate_only,
		char **	msg
	)

Read a netmask of the form 127.192.0.0/10 from "val", and check whether it's a valid set of virtual addresses to hand out in response to MAPADDRESS requests. Return 0 on success; set *msg (if provided) to a newly allocated string and return -1 on failure. If validate_only is false, sets the actual virtual address range to the parsed value.