curl/lib/hostip6.c
Jay Satiro 16e9c8e990 hostip: Make Curl_ipv6works function independent of getaddrinfo
- Do not assume IPv6 is not working when getaddrinfo is not present.

The check to see if IPv6 actually works is now independent of whether
there is any resolver that can potentially resolve a hostname to IPv6.

Prior to this change if getaddrinfo() was not found at compile time then
Curl_ipv6works() would be defined as a macro that returns FALSE.

When getaddrinfo is not found then libcurl is built with CURLRES_IPV4
defined instead of CURLRES_IPV6, meaning that it cannot do IPv6 lookups
in the traditional way. With this commit if libcurl is built with IPv6
support (ENABLE_IPV6) but without getaddrinfo (CURLRES_IPV6), and the
IPv6 stack is actually working, then it is possible for libcurl to
resolve IPv6 addresses by using DoH.

Ref: https://github.com/curl/curl/issues/7483#issuecomment-890765378

Closes https://github.com/curl/curl/pull/7529
2021-08-10 03:29:49 -04:00

162 lines
4.4 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2021, 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.
*
***************************************************************************/
#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
#ifdef HAVE_PROCESS_H
#include <process.h>
#endif
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "strerror.h"
#include "url.h"
#include "inet_pton.h"
#include "connect.h"
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
/*
* Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've
* been set and returns TRUE if they are OK.
*/
bool Curl_ipvalid(struct Curl_easy *data, struct connectdata *conn)
{
if(conn->ip_version == CURL_IPRESOLVE_V6)
return Curl_ipv6works(data);
return TRUE;
}
#if defined(CURLRES_SYNCH)
#ifdef DEBUG_ADDRINFO
static void dump_addrinfo(struct connectdata *conn,
const struct Curl_addrinfo *ai)
{
printf("dump_addrinfo:\n");
for(; ai; ai = ai->ai_next) {
char buf[INET6_ADDRSTRLEN];
printf(" fam %2d, CNAME %s, ",
ai->ai_family, ai->ai_canonname ? ai->ai_canonname : "<none>");
Curl_printable_address(ai, buf, sizeof(buf));
printf("%s\n", buf);
}
}
#else
#define dump_addrinfo(x,y) Curl_nop_stmt
#endif
/*
* Curl_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 forth 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_getaddrinfo(struct Curl_easy *data,
const char *hostname,
int port,
int *waitp)
{
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;
*waitp = 0; /* synchronous response only */
if(Curl_ipv6works(data))
/* The stack seems to be IPv6-enabled */
pf = PF_UNSPEC;
memset(&hints, 0, sizeof(hints));
hints.ai_family = pf;
hints.ai_socktype = (data->conn->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 Mac OS X.
*/
if((1 == Curl_inet_pton(AF_INET, hostname, addrbuf)) ||
(1 == Curl_inet_pton(AF_INET6, hostname, addrbuf))) {
/* the given address is numerical only, prevent a reverse lookup */
hints.ai_flags = AI_NUMERICHOST;
}
#endif
if(port) {
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);
}
dump_addrinfo(conn, res);
return res;
}
#endif /* CURLRES_SYNCH */
#endif /* CURLRES_IPV6 */