mirror of
https://gitlab.torproject.org/tpo/core/tor.git
synced 2024-11-11 21:53:48 +01:00
103 lines
3.8 KiB
C
103 lines
3.8 KiB
C
/* Copyright (c) 2003-2004, Roger Dingledine.
|
|
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
|
|
* Copyright (c) 2007-2017, The Tor Project, Inc. */
|
|
/* See LICENSE for licensing information */
|
|
|
|
/**
|
|
* \file dns_structs.h
|
|
*
|
|
* \brief Structures used in dns.c. Exposed to dns.c, and to the unit tests
|
|
* that declare DNS_PRIVATE.
|
|
*/
|
|
|
|
#ifndef TOR_DNS_STRUCTS_H
|
|
#define TOR_DNS_STRUCTS_H
|
|
|
|
/** Longest hostname we're willing to resolve. */
|
|
#define MAX_ADDRESSLEN 256
|
|
|
|
/** Linked list of connections waiting for a DNS answer. */
|
|
typedef struct pending_connection_t {
|
|
edge_connection_t *conn;
|
|
struct pending_connection_t *next;
|
|
} pending_connection_t;
|
|
|
|
/** Value of 'magic' field for cached_resolve_t. Used to try to catch bad
|
|
* pointers and memory stomping. */
|
|
#define CACHED_RESOLVE_MAGIC 0x1234F00D
|
|
|
|
/* Possible states for a cached resolve_t */
|
|
/** We are waiting for the resolver system to tell us an answer here.
|
|
* When we get one, or when we time out, the state of this cached_resolve_t
|
|
* will become "DONE" and we'll possibly add a CACHED
|
|
* entry. This cached_resolve_t will be in the hash table so that we will
|
|
* know not to launch more requests for this addr, but rather to add more
|
|
* connections to the pending list for the addr. */
|
|
#define CACHE_STATE_PENDING 0
|
|
/** This used to be a pending cached_resolve_t, and we got an answer for it.
|
|
* Now we're waiting for this cached_resolve_t to expire. This should
|
|
* have no pending connections, and should not appear in the hash table. */
|
|
#define CACHE_STATE_DONE 1
|
|
/** We are caching an answer for this address. This should have no pending
|
|
* connections, and should appear in the hash table. */
|
|
#define CACHE_STATE_CACHED 2
|
|
|
|
/** @name status values for a single DNS request.
|
|
*
|
|
* @{ */
|
|
/** The DNS request is in progress. */
|
|
#define RES_STATUS_INFLIGHT 1
|
|
/** The DNS request finished and gave an answer */
|
|
#define RES_STATUS_DONE_OK 2
|
|
/** The DNS request finished and gave an error */
|
|
#define RES_STATUS_DONE_ERR 3
|
|
/**@}*/
|
|
|
|
/** A DNS request: possibly completed, possibly pending; cached_resolve
|
|
* structs are stored at the OR side in a hash table, and as a linked
|
|
* list from oldest to newest.
|
|
*/
|
|
typedef struct cached_resolve_t {
|
|
HT_ENTRY(cached_resolve_t) node;
|
|
uint32_t magic; /**< Must be CACHED_RESOLVE_MAGIC */
|
|
char address[MAX_ADDRESSLEN]; /**< The hostname to be resolved. */
|
|
|
|
union {
|
|
uint32_t addr_ipv4; /**< IPv4 addr for <b>address</b>, if successful.
|
|
* (In host order.) */
|
|
int err_ipv4; /**< One of DNS_ERR_*, if IPv4 lookup failed. */
|
|
} result_ipv4; /**< Outcome of IPv4 lookup */
|
|
union {
|
|
struct in6_addr addr_ipv6; /**< IPv6 addr for <b>address</b>, if
|
|
* successful */
|
|
int err_ipv6; /**< One of DNS_ERR_*, if IPv6 lookup failed. */
|
|
} result_ipv6; /**< Outcome of IPv6 lookup, if any */
|
|
union {
|
|
char *hostname; /** A hostname, if PTR lookup happened successfully*/
|
|
int err_hostname; /** One of DNS_ERR_*, if PTR lookup failed. */
|
|
} result_ptr;
|
|
/** @name Status fields
|
|
*
|
|
* These take one of the RES_STATUS_* values, depending on the state
|
|
* of the corresponding lookup.
|
|
*
|
|
* @{ */
|
|
unsigned int res_status_ipv4 : 2;
|
|
unsigned int res_status_ipv6 : 2;
|
|
unsigned int res_status_hostname : 2;
|
|
/**@}*/
|
|
uint8_t state; /**< Is this cached entry pending/done/informative? */
|
|
|
|
time_t expire; /**< Remove items from cache after this time. */
|
|
uint32_t ttl_ipv4; /**< What TTL did the nameserver tell us? */
|
|
uint32_t ttl_ipv6; /**< What TTL did the nameserver tell us? */
|
|
uint32_t ttl_hostname; /**< What TTL did the nameserver tell us? */
|
|
/** Connections that want to know when we get an answer for this resolve. */
|
|
pending_connection_t *pending_connections;
|
|
/** Position of this element in the heap*/
|
|
int minheap_idx;
|
|
} cached_resolve_t;
|
|
|
|
#endif /* !defined(TOR_DNS_STRUCTS_H) */
|
|
|