bnf.c

Internet Phone, Chat, Conferencing

  if (span > maxspan)
    doublecolon = i - span, maxspan = span;

  dst = buf;

  for (i = 0; i < maxparts; i++) {
    if (i == doublecolon)
      hex = i == 0 ? "::" : ":", len = 1;
    else if (i > doublecolon && i < doublecolon + maxspan)
      continue;
    else
      hex = hexparts[i], len = span_hex4(hex);
    if (hex[len] == ':')
      len++;
    memcpy(dst, hex, len);
    dst += len;
  }

  if (ip4) {
    hex = ip4;
    len = scan_ip4_address(&hex); assert(len > 0);

    /* Canonize :: and ::1 */
    if (doublecolon == 0 && maxspan == 6) {
      if (len == 7 && strncmp(ip4, "0.0.0.0", len) == 0)
	ip4 = "", len = 0;
      else if (len == 7 && strncmp(ip4, "0.0.0.1", len) == 0)
	ip4 = "1", len = 1;
    }

    memcpy(dst, ip4, len);
    dst += len;
  }

  len = dst - buf;

  memcpy(host, buf, len);

  return len;
}

/** Return length of valid IP6 address */
int span_ip6_address(char const *host)
{
  return span_canonic_ip6_address(host, NULL, NULL);
}

/** Scan and canonize valid IP6 address.
 *
 * @param inout_host input pointer to string to scan
 *                   output pointer to first character after valid IP6 address
 *
 * @retval Length of valid IP6 address or -1 upon an error.
 *
 * @note Scanned IP6 is not NUL-terminated.
 */
int scan_ip6_address(char **inout_host)
{
  int n, canonize = 0;
  char *host = *inout_host;
  char *hexparts[9] = { NULL };

  n = span_canonic_ip6_address(host, &canonize, hexparts);

  if (n == 0)
    return -1;

  *inout_host += n;

  if (canonize) {
    int len = canonize_ip6_address(host, hexparts);
    assert(len <= n);
    if (len < n)
      host[len] = '\0';
  }

  return n;
}

/** Return length of valid IP6 reference. */
int span_ip6_reference(char const *host)
{
  /* IPv6reference  =  "[" IPv6address "]" */

  if (host[0] == '[') {
    int n = span_ip6_address(host + 1);
    if (n > 0 && host[n + 1] == ']')
      return n + 2;
  }

  return 0;
}

/** Scan valid IP6 reference. */
int scan_ip6_reference(char **inout_host)
{
  int n, canonize = 0;
  char *host = *inout_host;
  char *hexparts[9] = { NULL };

  /* IPv6reference  =  "[" IPv6address "]" */

  if (host == NULL ||
      host[0] != '[' ||
      (n = span_canonic_ip6_address(host + 1, &canonize, hexparts)) == 0 ||
      host[n + 1] != ']')
    return -1;

  *inout_host += n + 2;

  if (canonize) {
    int len = canonize_ip6_address(host + 1, hexparts);

    assert(len <= n);

    host[len + 1] = ']';
    if (len + 2 < n + 2)
      host[len + 2] = '\0';
  }

  return n + 2;
}

/** Return length of valid IP4 or IP6 address. */
int span_ip_address(char const *host)
{
  if (!host || !host[0])
    return 0;

  /* IPv4address = dec-octet "." dec-octet "." dec-octet "." dec-octet */
  if (IS_DIGIT(host[0])) {
    int n = span_ip4_address(host);
    if (n)
      return n;
  }

  if (host[0] == '[')
    return span_ip6_reference(host);
  else
    return span_ip6_address(host);
}

/** Scan valid IP4/IP6 address. */
int scan_ip_address(char **inout_host)
{
  char *host = *inout_host;

  if (host == NULL)
    return -1;

  /* IPv6reference  =  "[" IPv6address "]" */
  if (host[0] == '[')
    return scan_ip6_reference(inout_host);

  if (IS_DIGIT(host[0])) {
    int n = scan_ip4_address(inout_host);
    if (n > 0)
      return n;
  }

  return scan_ip6_address(inout_host);
}

/** Return length of a valid domain label */
static inline
int span_domain_label(char const *label)
{
  /* domainlabel =  alphanum / alphanum *( alphanum / "-" ) alphanum */
  if (IS_ALPHANUM(*label)) {
    int n;
    for (n = 1; IS_ALPHANUM(label[n]) || label[n] == '-'; n++)
      ;
    if (IS_ALPHANUM(label[n - 1]))
      return n;
  }

  return 0;
}

/** Scan valid domain name and count number of labels in it. */
static inline
int span_domain_labels(char const *host, int *return_labels)
{
  int len, n, labels, c;

  if (!host || !host[0])
    return 0;

  for (n = 0, labels = 0; ; n += len) {
    len = span_domain_label(host + n);
    if (len == 0)
      return 0;

    labels++;

    if (host[n + len] != '.')
      break;
    len++;
    if (!IS_ALPHANUM(host[n + len]))
      break;
  }

  /* Check that last label does not start with number */
  if (!IS_ALPHA(host[n]))
    return 0;

  c = host[n + len];
  if (IS_ALPHANUM(c) || c == '-' || c == '.')
    return 0;

  if (return_labels)
    *return_labels = labels;

  return n + len;
}

/** Return length of a valid domain name.
 *
 * @code
 * hostname         =  *( domainlabel "." ) toplabel [ "." ]
 * domainlabel      =  alphanum
 *                     / alphanum *( alphanum / "-" ) alphanum
 * toplabel         =  ALPHA / ALPHA *( alphanum / "-" ) alphanum
 * @endcode
 */
int span_domain(char const *host)
{
  return span_domain_labels(host, NULL);
}

/** Scan valid domain name. */
int scan_domain(char **inout_host)
{
  char *host;
  int n, labels;

  n = span_domain_labels(host = *inout_host, &labels);
  if (n == 0)
    return -1;

  /* Remove extra dot at the end of hostname */
  if (labels > 1 && host[n - 1] == '.')
    host[n - 1] = '\0';

  *inout_host += n;

  return n;
}

/** Return length of a valid domain name or IP address. */
int span_host(char const *host)
{
 if (!host || !host[0])
    return 0;

  if (host[0] == '[')
    return span_ip6_reference(host);

  if (IS_DIGIT(host[0])) {
    int n = span_ip4_address(host);
    if (n)
      return n;
  }

  return span_domain(host);
}

/** Scan valid domain name or IP address. */
int scan_host(char **inout_host)
{
  char *host = *inout_host;

  if (host == NULL)
    return -1;

  /* IPv6reference  =  "[" IPv6address "]" */
  if (host[0] == '[')
    return scan_ip6_reference(inout_host);

  if (IS_DIGIT(host[0])) {
    int n = scan_ip4_address(inout_host);
    if (n > 0)
      return n;
  }

  return scan_domain(inout_host);
}

#include <sofia-sip/hostdomain.h>

/** Return true if @a string is valid IP4 address in dot-notation.
 *
 * @note Only 4-octet form is accepted, e.g., @c 127.1 is not considered
 * valid IP4 address.
 */
int host_is_ip4_address(char const *string)
{
  int n = span_ip4_address(string);
  return n > 0 && string[n] == '\0';
}

/** Return true if @a string is valid IP6 address in hex notation.
 *
 * E.g., fe80::1 is a valid IP6 address. 
 */
int host_is_ip6_address(char const *string)
{
  int n = span_ip6_address(string);
  return n > 0 && string[n] == '\0';
}

/** Return true if @a string is valid IP6 reference, 
 *  i.e. hex notation in square brackets.
 *
 * E.g., [::1] is a valid IP6 reference.
 */
int host_ip6_reference(char const *string)
{
  int n = span_ip6_reference(string);
  return n > 0 && string[n] == '\0';
}

/** Return true if @a string is valid IP address.
 *
 * Valid IP address is either a IP4 adddress in quad-octet notation, 
 * IP6 hex address or IP6 reference in square brackets ([]).
 */
int host_is_ip_address(char const *string)
{
  int n = span_ip_address(string);
  return n > 0 && string[n] == '\0';
}

/** Return true if @a string is valid a domain name.
 *
 * Valid domain name consists of alphanumeric labels separated with 
 * dot ("."). There can be a "-" in the middle of label.
 * The last label must start with a letter.
 *
 * @code
 * hostname         =  *( domainlabel "." ) toplabel [ "." ]
 * domainlabel      =  alphanum
 *                     / alphanum *( alphanum / "-" ) alphanum
 * toplabel         =  ALPHA / ALPHA *( alphanum / "-" ) alphanum
 * @endcode
 */
int host_is_domain(char *string)
{
  int n = span_domain(string);
  return n > 0 && string[n] == '\0';
}

/** Return true if @a string is valid a host name.
 *
 * Check if the @a string is a domain name, IP address or IP6 reference.
 */
int host_is_valid(char const *string)
{
  int n = span_host(string);
  return n > 0 && string[n] == '\0';
}