tor
master
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Implements client-side DNS proxy server code. More...
#include "or.h"
#include "dnsserv.h"
#include "config.h"
#include "connection.h"
#include "connection_edge.h"
#include "control.h"
#include "main.h"
#include "policies.h"
#include <event2/dns.h>
#include <event2/dns_compat.h>
#include <event2/dns_struct.h>
Functions | |
int | dnsserv_launch_request (const char *name, int reverse, control_connection_t *control_conn) |
void | dnsserv_reject_request (entry_connection_t *conn) |
void | dnsserv_resolved (entry_connection_t *conn, int answer_type, size_t answer_len, const char *answer, int ttl) |
void | dnsserv_configure_listener (connection_t *conn) |
void | dnsserv_close_listener (connection_t *conn) |
Implements client-side DNS proxy server code.
When a user enables the DNSPort configuration option to have their local Tor client handle DNS requests, this module handles it. It functions as a "DNS Server" on the client side, which client applications use.
Inbound DNS requests are represented as entry_connection_t here (since that's how Tor represents client-side streams), which are kept associated with an evdns_server_request structure as exposed by Libevent's evdns code.
Upon receiving a DNS request, libevent calls our evdns_server_callback() function here, which causes this module to create an entry_connection_t request as appropriate. Later, when that request is answered, connection_edge.c calls dnsserv_resolved() so we can finish up and tell the DNS client.
void dnsserv_close_listener | ( | connection_t * | conn | ) |
Free the evdns server port for conn, which must be an AP_DNS_LISTENER.
void dnsserv_configure_listener | ( | connection_t * | conn | ) |
Set up the evdns server port for the UDP socket on conn, which must be an AP_DNS_LISTENER
int dnsserv_launch_request | ( | const char * | name, |
int | reverse, | ||
control_connection_t * | control_conn | ||
) |
Helper function: called whenever the client sends a resolve request to our controller. We need to eventually answer the request req. Returns 0 if the controller will be getting (or has gotten) an event in response; -1 if we couldn't launch the request.
void dnsserv_reject_request | ( | entry_connection_t * | conn | ) |
If there is a pending request on conn that's waiting for an answer, send back an error and free the request.
void dnsserv_resolved | ( | entry_connection_t * | conn, |
int | answer_type, | ||
size_t | answer_len, | ||
const char * | answer, | ||
int | ttl | ||
) |
Tell the dns request waiting for an answer on conn that we have an answer of type answer_type (RESOLVE_TYPE_IPV4/IPV6/ERR), of length answer_len, in answer, with TTL ttl. Doesn't do any caching; that's handled elsewhere.