curl-curl/lib/hostip.h
Stefan Eissing 56e40ae6a5
asyn resolver code improvements
"asyn" is the internal name under which both c-ares and threaded
resolver operate. Make the naming more consistent. Implement the c-ares
resolver in `asyn-ares.*` and the threaded resolver in `asyn-thrdd.*`.
The common functions are in `asyn-base.c`.

When `CURLRES_ASYNCH` is defined, either of the two is used and
`data->state.async` exists. Members of that struct vary for the selected
implementation, but have the fields `hostname`, `port` and `ip_version`
always present. This are populated when the async resolving starts and
eliminate the need to pass them again when checking on the status and
processing the results of the resolving.

Add a `Curl_resolv_blocking()` to `hostip.h` that relieves FTP and SOCKS
from having to repeat the same code.

`Curl_resolv_check()` remains the function to check for status of
ongoing resolving. Now it also performs internally the check if the
needed DNS entry exists in the dnscache and if so, aborts the asnyc
operation. (libcurl right now does not check for duplicate resolve
attempts. an area for future improvements).

The number of functions in `asyn.h` has been reduced. There were subtle
difference in "cancel()" and "kill()" calls, both replaced by
`Curl_async_shutdown()` now. This changes behaviour for threaded
resolver insofar as the resolving thread is now always joined unless
`data->set.quick_exit` is set. Before this was only done on some code
paths. A future improvement would be a thread pool that keeps a limit
and also could handle joins more gracefully.

DoH, not previously tagged under "asny", has its struct `doh_probes` now
also in `data->state.async`, moved there from `data->req` because it
makes more sense. Further integration of DoH underneath the "asyn"
umbrella seems like a good idea.

Closes #16963
2025-04-16 09:34:20 +02:00

211 lines
6.7 KiB
C

#ifndef HEADER_CURL_HOSTIP_H
#define HEADER_CURL_HOSTIP_H
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "curl_setup.h"
#include "hash.h"
#include "curl_addrinfo.h"
#include "timeval.h" /* for timediff_t */
#include "asyn.h"
#include "httpsrr.h"
#include <setjmp.h>
#ifdef USE_HTTPSRR
# include <stdint.h>
#endif
/* Allocate enough memory to hold the full name information structs and
* everything. OSF1 is known to require at least 8872 bytes. The buffer
* required for storing all possible aliases and IP numbers is according to
* Stevens' Unix Network Programming 2nd edition, p. 304: 8192 bytes!
*/
#define CURL_HOSTENT_SIZE 9000
#define CURL_TIMEOUT_RESOLVE 300 /* when using asynch methods, we allow this
many seconds for a name resolve */
#define CURL_ASYNC_SUCCESS CURLE_OK
struct addrinfo;
struct hostent;
struct Curl_easy;
struct connectdata;
enum alpnid {
ALPN_none = 0,
ALPN_h1 = CURLALTSVC_H1,
ALPN_h2 = CURLALTSVC_H2,
ALPN_h3 = CURLALTSVC_H3
};
struct Curl_dns_entry {
struct Curl_addrinfo *addr;
#ifdef USE_HTTPSRR
struct Curl_https_rrinfo *hinfo;
#endif
/* timestamp == 0 -- permanent CURLOPT_RESOLVE entry (does not time out) */
time_t timestamp;
/* reference counter, entry is freed on reaching 0 */
size_t refcount;
/* hostname port number that resolved to addr. */
int hostport;
/* hostname that resolved to addr. may be NULL (Unix domain sockets). */
char hostname[1];
};
struct Curl_dnscache {
struct Curl_hash entries;
};
bool Curl_host_is_ipnum(const char *hostname);
/*
* Curl_resolv() returns an entry with the info for the specified host
* and port.
*
* The returned data *MUST* be "released" with Curl_resolv_unlink() after
* use, or we will leak memory!
*/
CURLcode Curl_resolv(struct Curl_easy *data,
const char *hostname,
int port,
int ip_version,
bool allowDOH,
struct Curl_dns_entry **dnsentry);
CURLcode Curl_resolv_blocking(struct Curl_easy *data,
const char *hostname,
int port,
int ip_version,
struct Curl_dns_entry **dnsentry);
CURLcode Curl_resolv_timeout(struct Curl_easy *data,
const char *hostname, int port,
int ip_version,
struct Curl_dns_entry **dnsentry,
timediff_t timeoutms);
#ifdef USE_IPV6
/*
* Curl_ipv6works() returns TRUE if IPv6 seems to work.
*/
bool Curl_ipv6works(struct Curl_easy *data);
#else
#define Curl_ipv6works(x) FALSE
#endif
/* unlink a dns entry, potentially shared with a cache */
void Curl_resolv_unlink(struct Curl_easy *data,
struct Curl_dns_entry **pdns);
/* init a new dns cache */
void Curl_dnscache_init(struct Curl_dnscache *dns, size_t hashsize);
void Curl_dnscache_destroy(struct Curl_dnscache *dns);
/* prune old entries from the DNS cache */
void Curl_dnscache_prune(struct Curl_easy *data);
/* IPv4 threadsafe resolve function used for synch and asynch builds */
struct Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, int port);
CURLcode Curl_once_resolved(struct Curl_easy *data, bool *protocol_connect);
/*
* Curl_printable_address() returns a printable version of the 1st address
* given in the 'ip' argument. The result will be stored in the buf that is
* bufsize bytes big.
*/
void Curl_printable_address(const struct Curl_addrinfo *ip,
char *buf, size_t bufsize);
/*
* Make a `Curl_dns_entry`.
* Creates a dnscache entry *without* adding it to a dnscache. This allows
* further modifications of the entry *before* then adding it to a cache.
*
* The entry is created with a reference count of 1.
* Use `Curl_resolv_unlink()` to release your hold on it.
*
* The call takes ownership of `addr`and makes a copy of `hostname`.
*
* Returns entry or NULL on OOM.
*/
struct Curl_dns_entry *
Curl_dnscache_mk_entry(struct Curl_easy *data,
struct Curl_addrinfo *addr,
const char *hostname,
size_t hostlen, /* length or zero */
int port,
bool permanent);
/*
* Curl_dnscache_get() fetches a 'Curl_dns_entry' already in the DNS cache.
*
* Returns the Curl_dns_entry entry pointer or NULL if not in the cache.
*
* The returned data *MUST* be "released" with Curl_resolv_unlink() after
* use, or we will leak memory!
*/
struct Curl_dns_entry *
Curl_dnscache_get(struct Curl_easy *data,
const char *hostname,
int port, int ip_version);
/*
* Curl_dnscache_addr() adds `entry` to the cache, increasing its
* reference count on success.
*/
CURLcode Curl_dnscache_add(struct Curl_easy *data,
struct Curl_dns_entry *entry);
/*
* Populate the cache with specified entries from CURLOPT_RESOLVE.
*/
CURLcode Curl_loadhostpairs(struct Curl_easy *data);
CURLcode Curl_resolv_check(struct Curl_easy *data,
struct Curl_dns_entry **dns);
int Curl_resolv_getsock(struct Curl_easy *data,
curl_socket_t *socks);
CURLcode Curl_resolver_error(struct Curl_easy *data);
#ifdef CURLRES_SYNCH
/*
* Curl_sync_getaddrinfo() is the non-async low-level name resolve API.
* There are several versions of this function - depending on IPV6
* support and platform.
*/
struct Curl_addrinfo *Curl_sync_getaddrinfo(struct Curl_easy *data,
const char *hostname,
int port,
int ip_version);
#endif
#endif /* HEADER_CURL_HOSTIP_H */