hostip.c

/***************************************************************************
 *                                  _   _ ____  _     
 *  Project                     ___| | | |  _ \| |    
 *                             / __| | | | |_) | |    
 *                            | (__| |_| |  _ <| |___ 
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2004, 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 http://curl.haxx.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.
 *
 * $Id$
 ***************************************************************************/

#include "setup.h"

#include <string.h>
#include <errno.h>

#define _REENTRANT

#if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
#include <malloc.h>
#else
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#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 HAVE_STDLIB_H
#include <stdlib.h>	/* required for free() prototypes */
#endif
#ifdef	VMS
#include <in.h>
#include <inet.h>
#include <stdlib.h>
#endif
#endif

#ifdef HAVE_SETJMP_H
#include <setjmp.h>
#endif

#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
#undef in_addr_t
#define in_addr_t unsigned long
#endif

#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "url.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

#if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
#include "inet_ntoa_r.h"
#endif

/* The last #include file should be: */
#ifdef CURLDEBUG
#include "memdebug.h"
#endif

#ifndef ARES_SUCCESS
#define ARES_SUCCESS CURLE_OK
#endif

#define CURL_TIMEOUT_RESOLVE 300 /* when using asynch methods, we allow this
                                    many seconds for a name resolve */

/* These two symbols are for the global DNS cache */
static curl_hash hostname_cache;
static int host_cache_initialized;


static void freednsentry(void *freethis);

/*
 * my_getaddrinfo() is the generic low-level name resolve API within this
 * source file. There exist three versions of this function - for different
 * name resolve layers (selected at build-time). They all take this same set
 * of arguments
 */
static Curl_addrinfo *my_getaddrinfo(struct connectdata *conn,
                                     char *hostname,
                                     int port,
                                     int *waitp);
#ifndef ENABLE_IPV6
#if !defined(HAVE_GETHOSTBYNAME_R) || defined(USE_ARES) || \
    defined(USE_THREADING_GETHOSTBYNAME)
static struct hostent* pack_hostent(char** buf, struct hostent* orig);
#endif
#endif

#ifdef USE_THREADING_GETHOSTBYNAME
#ifdef DEBUG_THREADING_GETHOSTBYNAME
/* If this is defined, provide tracing */
#define TRACE(args)  \
 do { trace_it("%u: ", __LINE__); trace_it args; } while (0)

static void trace_it (const char *fmt, ...);
#else
#define TRACE(x)
#endif

static struct hostent* pack_hostent (char** buf, struct hostent* orig);
static bool init_gethostbyname_thread (struct connectdata *conn,
                                       const char *hostname, int port);
struct thread_data {
  HANDLE thread_hnd;
  DWORD  thread_id;
  DWORD  thread_status;
};
#endif

/*
 * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
 * Global DNS cache is general badness. Do not use. This will be removed in
 * a future version. Use the share interface instead!
 */
void Curl_global_host_cache_init(void)
{
  if (!host_cache_initialized) {
    Curl_hash_init(&hostname_cache, 7, freednsentry);
    host_cache_initialized = 1;
  }
}

/*
 * Return a pointer to the global cache
 */
curl_hash *Curl_global_host_cache_get(void)
{
  return &hostname_cache;
}

/*
 * Destroy and cleanup the global DNS cache
 */
void Curl_global_host_cache_dtor(void)
{
  if (host_cache_initialized) {
    Curl_hash_clean(&hostname_cache);
    host_cache_initialized = 0;
  }
}

/*
 * Minor utility-function:
 * Count the number of characters that an integer takes up.
 */
static int _num_chars(int i)
{
  int chars = 0;

  /* While the number divided by 10 is greater than one, 
   * re-divide the number by 10, and increment the number of 
   * characters by 1.
   *
   * this relies on the fact that for every multiple of 10, 
   * a new digit is added onto every number
   */
  do {
    chars++;

    i = (int) i / 10;
  } while (i >= 1);

  return chars;
}

/*
 * Minor utility-function:
 * Create a hostcache id string for the DNS caching.
 */
static char *
create_hostcache_id(char *server, int port, size_t *entry_len)