curl-curl/lib/hostip6.c
Stefan Eissing 2b3dfb4ad4
lib: make resolving HTTPS DNS records reliable:
- allow to specify when they are wanted on starting a resolve
- match dns cache entries accordingly. An entry which never
  tried to get HTTPS-RRs is no answer for a resolve that wants
  it.
- fix late arrivals of resolve answers to match the "async"
  records that started them - if it still exists.
- provide for multiple "async" resolves in a transfer at the
  same time. We may need to resolve an IP interface while the
  main connection resolve has not finished yet.
- allow lookup of HTTPS-RR information as soon as it is
  available, even if A/AAAA queries are still ongoing.

For this, the "async" infrastructure is changed:

- Defined bits for DNS queries `CURL_DNSQ_A`, `CURL_DNSQ_AAAA`
  and `CURL_DNSQ_HTTPS`. These replace `ip_version` which says
  nothing about HTTPS.
  Use them in dns cache entries for matching.
- enhance the `async->id` to be a unique `uint32_t` for
  resolves inside one multi. This is weak, as the id may
  wrap around. However it is combined with the `mid` of
  the easy handle, making collisions highly unlikely.
  `data->state.async` is only accessed in few places where
  the mid/async-id match is performed.
- vtls: for ECH supporting TLS backends (openssl, rustls, wolfssl),
  retrieve the HTTPS-RR information from the dns connection filter.
  Delay the connect if the HTTPS-RR is needed, but has not
  been resolved yet.

The implementation of all this is complete for the threaded
resolver. c-ares resolver and DoH do not take advantage of
all new async features yet. To be done in separate PRs.

Details:

c-ares: cleanup settings and initialisation. Any ares channel
is only being created on starting a resolve and propagating
operations in setopt.c to the channel are not helpful.

Changed threaded+ares pollset handling so that they do not
overwrite each others `ASYNC_NAME` timeouts.

Add trace name 'threads' for tracing thread queue and
pool used by threaded resolver.

Closes #21175
2026-04-01 15:36:31 +02:00

121 lines
3.4 KiB
C

/***************************************************************************
* _ _ ____ _
* 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"
/***********************************************************************
* Only for IPv6-enabled builds
**********************************************************************/
#ifdef CURLRES_IPV6
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef __VMS
#include <in.h>
#include <inet.h>
#endif
#include "urldata.h"
#include "cfilters.h"
#include "curl_addrinfo.h"
#include "curl_trc.h"
#include "hostip.h"
#include "url.h"
#include "curlx/inet_pton.h"
#include "connect.h"
#ifdef CURLRES_SYNCH
/*
* Curl_sync_getaddrinfo() when built IPv6-enabled (non-threading and
* non-ares version).
*
* Returns name information about the given hostname and port number. If
* successful, the 'addrinfo' is returned and the fourth argument will point
* to memory we need to free after use. That memory *MUST* be freed with
* Curl_freeaddrinfo(), nothing else.
*/
struct Curl_addrinfo *Curl_sync_getaddrinfo(struct Curl_easy *data,
uint8_t dns_queries,
const char *hostname,
uint16_t port,
uint8_t transport)
{
struct addrinfo hints;
struct Curl_addrinfo *res;
int error;
char sbuf[12];
char *sbufptr = NULL;
#ifndef USE_RESOLVE_ON_IPS
char addrbuf[128];
#endif
int pf = PF_INET;
if(dns_queries & CURL_DNSQ_AAAA)
pf = PF_UNSPEC;
memset(&hints, 0, sizeof(hints));
hints.ai_family = pf;
hints.ai_socktype = (transport == TRNSPRT_TCP) ?
SOCK_STREAM : SOCK_DGRAM;
#ifndef USE_RESOLVE_ON_IPS
/*
* The AI_NUMERICHOST must not be set to get synthesized IPv6 address from
* an IPv4 address on iOS and macOS.
*/
if((curlx_inet_pton(AF_INET, hostname, addrbuf) == 1) ||
(curlx_inet_pton(AF_INET6, hostname, addrbuf) == 1)) {
/* the given address is numerical only, prevent a reverse lookup */
hints.ai_flags = AI_NUMERICHOST;
}
#endif
if(port) {
curl_msnprintf(sbuf, sizeof(sbuf), "%d", port);
sbufptr = sbuf;
}
error = Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &res);
if(error) {
infof(data, "getaddrinfo(3) failed for %s:%d", hostname, port);
return NULL;
}
if(port) {
Curl_addrinfo_set_port(res, port);
}
return res;
}
#endif /* CURLRES_SYNCH */
#endif /* CURLRES_IPV6 */