host.c

wget (command line browser) source code

  if (sa->sa.sa_family == AF_INET)
      return htons (sa->sin.sin_port);
#ifdef ENABLE_IPV6
  if (sa->sa.sa_family == AF_INET6)
      return htons (sa->sin6.sin6_port);
#endif
  abort();
  /* do not complain about return nothing */
  return -1;
}

/**
  * sockaddr_len
  *
  * This function return the length of the sockaddr corresponding to 
  * the acutall prefered protocol for (bind, connect etc...)
  * Unsuported adress family will abort the whole programm.
  * 
  * Require:
  * that the IP-Protocol already is set.
  *
  * Input:
  * -		Public IP-Family Information
  *
  * Output:
  * socklen_t	structure length for socket options
  */
socklen_t
sockaddr_len () 
{
  if (ip_default_family == AF_INET) 
    return sizeof (struct sockaddr_in);
#ifdef ENABLE_IPV6
  if (ip_default_family == AF_INET6) 
    return sizeof (struct sockaddr_in6);
#endif
  abort();
  /* do not complain about return nothing */
  return 0;
}

/**
  * Map an IPv4 adress to the internal adress format.
  */
void 
map_ipv4_to_ip (ip4_address *ipv4, ip_address *ip) 
{
#ifdef ENABLE_IPV6
  static unsigned char ipv64[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff};
  memcpy ((char *)ip + 12, ipv4 , 4);
  memcpy ((char *)ip + 0, ipv64, 12);
#else
  if ((char *)ip != (char *)ipv4)
    memcpy (ip, ipv4, 4);
#endif
}

/* Detect whether an IP adress represents an IPv4 address and, if so,
   copy it to IPV4.  0 is returned on failure.
   This operation always succeeds when Wget is compiled without IPv6.
   If IPV4 is NULL, don't copy, just detect.  */

int 
map_ip_to_ipv4 (ip_address *ip, ip4_address *ipv4) 
{
#ifdef ENABLE_IPV6
  static unsigned char ipv64[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff};
  if (0 != memcmp (ip, ipv64, 12))
    return 0;
  if (ipv4)
    memcpy (ipv4, (char *)ip + 12, 4);
#else
  if (ipv4)
    memcpy (ipv4, (char *)ip, 4);
#endif
  return 1;
}

/* Versions of gethostbyname and getaddrinfo that support timeout. */

#ifndef ENABLE_IPV6

struct ghbnwt_context {
  const char *host_name;
  struct hostent *hptr;
};

static void
gethostbyname_with_timeout_callback (void *arg)
{
  struct ghbnwt_context *ctx = (struct ghbnwt_context *)arg;
  ctx->hptr = gethostbyname (ctx->host_name);
}

/* Just like gethostbyname, except it times out after TIMEOUT seconds.
   In case of timeout, NULL is returned and errno is set to ETIMEDOUT.
   The function makes sure that when NULL is returned for reasons
   other than timeout, errno is reset.  */

static struct hostent *
gethostbyname_with_timeout (const char *host_name, double timeout)
{
  struct ghbnwt_context ctx;
  ctx.host_name = host_name;
  if (run_with_timeout (timeout, gethostbyname_with_timeout_callback, &ctx))
    {
      SET_H_ERRNO (HOST_NOT_FOUND);
      errno = ETIMEDOUT;
      return NULL;
    }
  if (!ctx.hptr)
    errno = 0;
  return ctx.hptr;
}

#else  /* ENABLE_IPV6 */

struct gaiwt_context {
  const char *node;
  const char *service;
  const struct addrinfo *hints;
  struct addrinfo **res;
  int exit_code;
};

static void
getaddrinfo_with_timeout_callback (void *arg)
{
  struct gaiwt_context *ctx = (struct gaiwt_context *)arg;
  ctx->exit_code = getaddrinfo (ctx->node, ctx->service, ctx->hints, ctx->res);
}

/* Just like getaddrinfo, except it times out after TIMEOUT seconds.
   In case of timeout, the EAI_SYSTEM error code is returned and errno
   is set to ETIMEDOUT.  */

static int
getaddrinfo_with_timeout (const char *node, const char *service,
			  const struct addrinfo *hints, struct addrinfo **res,
			  double timeout)
{
  struct gaiwt_context ctx;
  ctx.node = node;
  ctx.service = service;
  ctx.hints = hints;
  ctx.res = res;

  if (run_with_timeout (timeout, getaddrinfo_with_timeout_callback, &ctx))
    {
      errno = ETIMEDOUT;
      return EAI_SYSTEM;
    }
  return ctx.exit_code;
}

#endif /* ENABLE_IPV6 */

/* Pretty-print ADDR.  When compiled without IPv6, this is the same as
   inet_ntoa.  With IPv6, it either prints an IPv6 address or an IPv4
   address.  */

char *
pretty_print_address (ip_address *addr)
{
#ifdef ENABLE_IPV6
  ip4_address addr4;
  static char buf[128];

  if (map_ip_to_ipv4 (addr, &addr4))
    return inet_ntoa (*(struct in_addr *)&addr4);

  if (!inet_ntop (AF_INET6, addr, buf, sizeof (buf)))
    return "<unknown>";
  return buf;
#endif
  return inet_ntoa (*(struct in_addr *)addr);
}

/* Add host name HOST with the address ADDR_TEXT to the cache.
   ADDR_LIST is a NULL-terminated list of addresses, as in struct
   hostent.  */

static void
cache_host_lookup (const char *host, struct address_list *al)
{
  if (!host_name_addresses_map)
    host_name_addresses_map = make_nocase_string_hash_table (0);

  ++al->refcount;
  hash_table_put (host_name_addresses_map, xstrdup_lower (host), al);

#ifdef ENABLE_DEBUG
  if (opt.debug)
    {
      int i;
      debug_logprintf ("Caching %s =>", host);
      for (i = 0; i < al->count; i++)
	debug_logprintf (" %s", pretty_print_address (al->addresses + i));
      debug_logprintf ("\n");
    }
#endif
}

struct address_list *
lookup_host (const char *host, int silent)
{
  struct address_list *al = NULL;
  uint32_t addr_ipv4;
  ip_address addr;

  /* First, try to check whether the address is already a numeric
     address.  */

#ifdef ENABLE_IPV6
  if (inet_pton (AF_INET6, host, &addr) > 0)
    return address_list_from_single (&addr);
#endif

  addr_ipv4 = (uint32_t)inet_addr (host);
  if (addr_ipv4 != (uint32_t)-1)
    {
      /* ADDR is defined to be in network byte order, which is what
	 this returns, so we can just copy it to STORE_IP.  */
      map_ipv4_to_ip ((ip4_address *)&addr_ipv4, &addr);
      return address_list_from_single (&addr);
    }

  if (host_name_addresses_map)
    {
      al = hash_table_get (host_name_addresses_map, host);
      if (al)
	{
	  DEBUGP (("Found %s in host_name_addresses_map (%p)\n", host, al));
	  ++al->refcount;
	  return al;
	}
    }

  if (!silent)
    logprintf (LOG_VERBOSE, _("Resolving %s... "), host);

  /* Host name lookup goes on below. */

#ifdef HAVE_GETADDRINFO
  {
    struct addrinfo hints, *ai;
    int err;

    memset (&hints, 0, sizeof (hints));
    if (ip_default_family == AF_INET)
      hints.ai_family   = AF_INET;
    else
      hints.ai_family   = PF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    err = getaddrinfo_with_timeout (host, NULL, &hints, &ai, opt.dns_timeout);

    if (err != 0 || ai == NULL)
      {
        if (!silent)
	  logprintf (LOG_VERBOSE, _("failed: %s.\n"),
		     err != EAI_SYSTEM ? gai_strerror (err) : strerror (errno));
        return NULL;
      }
    al = address_list_from_addrinfo (ai);
    freeaddrinfo (ai);
  }
#else
  {
    struct hostent *hptr;
    hptr = gethostbyname_with_timeout (host, opt.dns_timeout);
    if (!hptr)
      {
	if (!silent)
	  {
	    if (errno != ETIMEDOUT)
	      logprintf (LOG_VERBOSE, _("failed: %s.\n"), herrmsg (h_errno));
	    else
	      logputs (LOG_VERBOSE, _("failed: timed out.\n"));
	  }
	return NULL;
      }
    /* Do all systems have h_addr_list, or is it a newer thing?  If
       the latter, use address_list_from_single.  */
    al = address_list_from_vector (hptr->h_addr_list);
  }
#endif

  /* Print the addresses determined by DNS lookup, but no more than
     three.  */
  if (!silent)
    {
      int i;
      int printmax = al->count <= 3 ? al->count : 3;
      for (i = 0; i < printmax; i++)
	{
	  logprintf (LOG_VERBOSE, "%s",
		     pretty_print_address (al->addresses + i));
	  if (i < printmax - 1)
	    logputs (LOG_VERBOSE, ", ");
	}
      if (printmax != al->count)
	logputs (LOG_VERBOSE, ", ...");
      logputs (LOG_VERBOSE, "\n");
    }

  /* Cache the lookup information. */
  if (opt.dns_cache)
    cache_host_lookup (host, al);

  return al;
}

/* Determine whether a URL is acceptable to be followed, according to
   a list of domains to accept.  */
int
accept_domain (struct url *u)
{
  assert (u->host != NULL);
  if (opt.domains)
    {
      if (!sufmatch ((const char **)opt.domains, u->host))
	return 0;
    }
  if (opt.exclude_domains)
    {
      if (sufmatch ((const char **)opt.exclude_domains, u->host))
	return 0;
    }
  return 1;
}

/* Check whether WHAT is matched in LIST, each element of LIST being a
   pattern to match WHAT against, using backward matching (see
   match_backwards() in utils.c).

   If an element of LIST matched, 1 is returned, 0 otherwise.  */
int
sufmatch (const char **list, const char *what)
{
  int i, j, k, lw;

  lw = strlen (what);
  for (i = 0; list[i]; i++)
    {
      for (j = strlen (list[i]), k = lw; j >= 0 && k >= 0; j--, k--)
	if (TOLOWER (list[i][j]) != TOLOWER (what[k]))
	  break;
      /* The domain must be first to reach to beginning.  */
      if (j == -1)
	return 1;
    }
  return 0;
}

/* Print error messages for host errors.  */
char *
herrmsg (int error)
{
  /* Can't use switch since some constants are equal (at least on my
     system), and the compiler signals "duplicate case value".  */
  if (error == HOST_NOT_FOUND
      || error == NO_RECOVERY
      || error == NO_DATA
      || error == NO_ADDRESS
      || error == TRY_AGAIN)
    return _("Host not found");
  else
    return _("Unknown error");
}

static int
host_cleanup_mapper (void *key, void *value, void *arg_ignored)
{
  struct address_list *al;

  xfree (key);			/* host */

  al = (struct address_list *)value;
  assert (al->refcount == 1);
  address_list_delete (al);

  return 0;
}

void
host_cleanup (void)
{
  if (host_name_addresses_map)
    {
      hash_table_map (host_name_addresses_map, host_cleanup_mapper, NULL);
      hash_table_destroy (host_name_addresses_map);
      host_name_addresses_map = NULL;
    }
}