bnf.c

Sofia SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification.

 * @retval Length of valid IP6 address or -1 upon an error.
 *
 * @note Scanned IP6 is not always 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 && 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 */
su_inline
size_t span_domain_label(char const *label)
{
  /* domainlabel =  alphanum / alphanum *( alphanum / "-" ) alphanum */
  if (IS_ALPHANUM(*label)) {
    size_t 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. */
su_inline
size_t span_domain_labels(char const *host, size_t *return_labels)
{
  size_t len, n, labels;
  int 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
 */
isize_t span_domain(char const *host)
{
  return span_domain_labels(host, NULL);
}

/** Scan valid domain name. */
issize_t scan_domain(char **inout_host)
{
  char *host;
  size_t 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. */
isize_t 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 (isize_t)n;
  }

  return span_domain(host);
}

/** Scan valid domain name or IP address. */
issize_t 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 (issize_t)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';
}

int host_ip6_reference(char const *string)
{
  return host_is_ip6_reference(string);
}

/** 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_is_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 const *string)
{
  size_t n = string ? span_domain(string) : 0;
  return string && 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)
{
  size_t n = span_host(string);
  return n > 0 && string[n] == '\0';
}

/** Returns true if @a string is describing a local address.
 *
 * Uses the definitions of local addresses found in RFC1700 and 
 * RFC4291. 
 */
int host_is_local(char const *host)
{
  size_t n;

  if (host_is_ip6_reference(host))
    return (strcmp(host, "[::1]") == 0);
  else if (host_is_ip6_address(host))
    return (strcmp(host, "::1") == 0);
  else if (host_is_ip4_address(host))
    return (strncmp(host, "127.", 4) == 0);

  n = span_domain(host);

  return 
    n >= 9 /* strlen("localhost") */ &&
    strncasecmp(host, "localhost", 9) == 0 &&
    (n == 9 || 
     ((n == 10 || /* localhost. */
       n == 21 || /* strlen("localhost.localdomain") */
       n == 22) && /* strlen("localhost.localdomain.") */
      strncasecmp(host + 9, ".localdomain.", n - 9) == 0));
}

/** Return true if @a string has domain name in "invalid." domain.
 *
 */
int host_has_domain_invalid(char const *string)
{
  size_t n = span_domain(string);

  if (n >= 7 && string[n] == '\0') {
    static char const invalid[] = ".invalid";
    if (string[n - 1] == '.')	/* .invalid. perhaps? */
      n--;
    if (n == 7 /* strlen("invalid") */)
      return strncasecmp(string, invalid + 1, 7) == 0;
    else
      return strncasecmp(string + n - 8, invalid, 8) == 0;
  }

  return 0;
}

#include <sofia-sip/su.h>

static size_t convert_ip_address(char const *s,
				 uint8_t addr[16],
				 size_t *return_addrlen)
{
  size_t len;
  int canonize = 0;
  char buf[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];

#if SU_HAVE_IN6

  len = span_ip6_reference(s);
  if (len) {
    assert(len - 2 < sizeof buf); assert(len > 2);

    if (s[len])
      return 0;

    len = len - 2;
    s = memcpy(buf, s + 1, len), buf[len] = '\0';
  }
  else
    len = span_ip6_address(s);

  if (len) {
    if (s[len] == '\0' && su_inet_pton(AF_INET6, s, addr) == 1) {
      if (SU_IN6_IS_ADDR_V4MAPPED(addr) ||
	  SU_IN6_IS_ADDR_V4COMPAT(addr)) {
	memcpy(addr, addr + 12, 4);
	return (void)(*return_addrlen = 4), len;
      }
      return (void)(*return_addrlen = 16), len;
    }
  }
  else
#endif
  len = span_canonic_ip4_address(s, &canonize);

  if (len) {
    if (canonize) {
      char *tmp = buf;
      s = memcpy(tmp, s, len + 1);
      scan_ip4_address(&tmp);      
    }
    if (s[len] == '\0' && su_inet_pton(AF_INET, s, addr) == 1)
      return (void)(*return_addrlen = 4), len;
  }

  return 0;
}

/** Compare two host names or IP addresses
 *
 * Converts valid IP addresses to the binary format before comparing them. 
 * Note that IP6-mapped IP4 addresses and IP6-compatible IP4 addresses are
 * compared as IP4 addresses; that is, ::ffff:127.0.0.1, ::127.0.0.1 and
 * 127.0.0.1 all are all equal.
 *
 * @param a IP address or domain name
 * @param b IP address or domain name
 * 
 * @retval -1 if a < b
 * @retval 0 if a == b
 * @retval 1 if a > b
 *
 * @since New in @VERSION_1_12_4.
 */
int host_cmp(char const *a, char const *b)
{
  uint8_t a6[16], b6[16];
  size_t alen, blen, asize = 0, bsize = 0;
  int retval;

  if (a == NULL || b == NULL) {
    retval = (a != NULL) - (b != NULL);
  }
  else {
    alen = convert_ip_address(a, a6, &asize);
    blen = convert_ip_address(b, b6, &bsize);

    if (alen > 0 && blen > 0) {
      if (asize < bsize)
	retval = -1;
      else if (asize > bsize)
	retval = 1;
      else
	retval = memcmp(a6, b6, asize);
    }
    else {
      retval = strcasecmp(a, b);
    }
  }

  return retval;
}