url.c

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

/*
 * This file is part of the Sofia-SIP package
 *
 * Copyright (C) 2005 Nokia Corporation.
 *
 * Contact: Pekka Pessi <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

/**@CFILE url.c
 *
 * Implementation of basic URL parsing and handling.
 *
 * @author Pekka Pessi <[e-mail]>
 *
 * @date Created: Thu Jun 29 22:44:37 2000 ppessi
 */

#include "config.h"

#include <sofia-sip/su_alloc.h>
#include <sofia-sip/bnf.h>
#include <sofia-sip/hostdomain.h>
#include <sofia-sip/url.h>

#include <sofia-sip/string0.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <ctype.h>
#include <limits.h>

/**@def URL_PRINT_FORMAT
 * Format string used when printing url with printf().
 *
 * The macro URL_PRINT_FORMAT is used in format string of printf() or
 * similar printing functions.  A URL can be printed like this:
 * @code
 *   printf("%s received URL " URL_PRINT_FORMAT "\n", 
 *          my_name, URL_PRINT_ARGS(url));
 * @endcode
 */

/** @def URL_PRINT_ARGS(u)
 * Argument list used when printing url with printf().
 *
 * The macro URL_PRINT_ARGS() is used to create a stdarg list for printf()
 * or similar printing functions.  Using it, a URL can be printed like this:
 *
 * @code
 *   printf("%s received URL " URL_PRINT_FORMAT "\n", 
 *          my_name, URL_PRINT_ARGS(url));
 * @endcode
 */

#define RESERVED        ";/?:@&=+$,"
#define DELIMS          "<>#%\""
#define UNWISE		"{}|\\^[]`"

#define EXCLUDED	RESERVED DELIMS UNWISE

#define UNRESERVED    	"ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
                      	"abcdefghijklmnopqrstuvwxyz" \
                      	"0123456789" \
                      	"-_.!~*'()"

#define IS_EXCLUDED(u, m32, m64, m96)			\
  (u <= ' '						\
   || u >= '\177'					\
   || (u < 64 ? (m32 & (1 << (63 - u)))			\
       : (u < 96 ? (m64 & (1 << (95 - u)))		\
	  : /*u < 128*/ (m96 & (1 << (127 - u))))) != 0)

#define MASKS_WITH_RESERVED(reserved, m32, m64, m96)		\
  if (reserved == NULL) {					\
    m32 = 0xbe19003f, m64 = 0x8000001e, m96 = 0x8000001d;	\
  } else do {							\
    m32 = 0xb400000a, m64 = 0x0000001e, m96 = 0x8000001d;	\
    								\
    for (;reserved[0]; reserved++) {				\
      unsigned r = reserved[0];					\
      RESERVE(r, m32, m64, m96);				\
    }								\
  } while (0)

#define RESERVE(reserved, m32, m64, m96)				\
  if (r < 32)								\
    ;									\
  else if (r < 64)							\
    m32 |= 1U << (63 - r);						\
  else if (r < 96)							\
    m64 |= 1U << (95 - r);						\
  else if (r < 128)							\
    m96 |= 1U << (127 - r)

#define MASKS_WITH_ALLOWED(allowed, mask32, mask64, mask96)	\
  do {								\
    if (allowed) {						\
      for (;allowed[0]; allowed++) {				\
	unsigned a = allowed[0];				\
	ALLOW(a, mask32, mask64, mask96);			\
      }								\
    }								\
  } while (0)

#define ALLOW(a, mask32, mask64, mask96)	\
  if (a < 32)					\
    ;						\
  else if (a < 64)				\
    mask32 &= ~(1U << (63 - a));		\
  else if (a < 96)				\
    mask64 &= ~(1U << (95 - a));		\
  else if (a < 128)				\
    mask96 &= ~(1U << (127 - a))

#define NUL '\0'
#define NULNULNUL '\0', '\0', '\0'

#define RMASK1 0xbe19003f
#define RMASK2 0x8000001e
#define RMASK3 0x8000001d

#define RESERVED_MASK 0xbe19003f, 0x8000001e, 0x8000001d
#define URIC_MASK     0xb400000a, 0x0000001e, 0x8000001d

#define IS_EXCLUDED_MASK(u, m) IS_EXCLUDED(u, m)

/* Internal prototypes */
static char *url_canonize(char *d, char const *s, size_t n,
			  unsigned syn33,
			  char const allowed[]);
static char *url_canonize2(char *d, char const *s, size_t n, 
			   unsigned syn33,
			   unsigned m32, unsigned m64, unsigned m96);
static int url_tel_cmp_numbers(char const *A, char const *B);

/**Test if string contains excluded or url-reserved characters. 
 *
 * 
 *
 * @param s  string to be searched
 *
 * @retval 0 if no reserved characters were found.
 * @retval l if a reserved character was found.
 */
int url_reserved_p(char const *s)
{
  if (s) 
    while (*s) {
      unsigned char u = *s++;

      if (IS_EXCLUDED(u, RMASK1, RMASK2, RMASK3))
	return 1;
    }

  return 0;
}

/** Calculate length of string when escaped with %-notation.
 *
 * Calculate the length of string @a s when the excluded or reserved
 * characters in it have been escaped.
 * 
 * @param s         String with reserved URL characters. [IN
 * @param reserved  Optional array of reserved characters [IN]
 *
 * @return 
 * The number of characters in corresponding but escaped string.
 *
 * You can handle a part of URL with reserved characters like this:
 *燖code
 * if (url_reserved_p(s))  {
 *   n = malloc(url_esclen(s, NULL) + 1);
 *   if (n) url_escape(n, s);
 * } else {
 *   n = malloc(strlen(s) + 1);
 *   if (n) strcpy(n, s);
 * }
 * @endcode
 */
isize_t url_esclen(char const *s, char const reserved[])
{
  size_t n;
  unsigned mask32, mask64, mask96;

  MASKS_WITH_RESERVED(reserved, mask32, mask64, mask96);

  for (n = 0; s && *s; n++) {
    unsigned char u = *s++;

    if (IS_EXCLUDED(u, mask32, mask64, mask96))
      n += 2;
  }

  return (isize_t)n;
}

/** Escape a string.
 *
 * The function url_escape() copies the string pointed by @a s to the array
 * pointed by @a d, @b excluding the terminating \\0 character.  All reserved
 * characters in @a s are copied in hexadecimal format, for instance, @c
 * "$%#" is copied as @c "%24%25%23".  The destination array @a d must be
 * large enough to receive the escaped copy.
 *
 * @param d         Destination buffer [OUT]
 * @param s         String to be copied [IN]
 * @param reserved  Array of reserved characters [IN]
 *
 * @return Pointer to the destination array.
 */
char *url_escape(char *d, char const *s, char const reserved[])
{
  char *retval = d;
  unsigned mask32, mask64, mask96;
 
  MASKS_WITH_RESERVED(reserved, mask32, mask64, mask96);

  while (s && *s) {
    unsigned char u = *s++;

    if (IS_EXCLUDED(u, mask32, mask64, mask96)) {
#     define URL_HEXIFY(u) ((u) + '0' + ((u) >= 10 ? 'A' - '0' - 10 : 0))

      *d++ = '%';
      *d++ = URL_HEXIFY(u >> 4);
      *d++ = URL_HEXIFY(u & 15);

#     undef URL_HEXIFY
    }
    else {
      *d++ = u;
    }
  }

  *d = '\0';
  
  return retval;
}


/**Unescape url-escaped string fragment.
 *
 * Unescape @a n characters from string @a s to the buffer @a d, including
 * the terminating \\0 character. All %-escaped triplets in @a s are
 * unescaped, for instance, @c "%40%25%23" is copied as @c "@%#". The
 * destination array @a d must be large enough to receive the escaped copy
 * (@a n bytes is always enough).
 *
 * @param d  destination buffer
 * @param s  string to be unescaped
 * @param n  maximum number of characters to unescape
 *
 * @return Length of unescaped string
 *
 * @NEW_1_12_4.
 */
size_t url_unescape_to(char *d, char const *s, size_t n)
{
  size_t i = 0, j = 0;

  if (s == NULL)
    return 0;

  i = j = strncspn(s, n, "%");

  if (d && d != s)
    memmove(d, s, i);

  for (; i < n;) {
    char c = s[i++];

    if (c == '\0')
      break;

    if (c == '%' && i + 1 < n && IS_HEX(s[i]) && IS_HEX(s[i + 1])) {
#define   UNHEX(a) (a - (a >= 'a' ? 'a' - 10 : (a >= 'A' ? 'A' - 10 : '0')))
      c = (UNHEX(s[i]) << 4) | UNHEX(s[i + 1]);
#undef    UNHEX
      i += 2;
    }

    if (d)
      d[j] = c;
    j++;
  }

  return j;
}

/**Unescape url-escaped string.
 *
 * Unescape string @a s to the buffer @a d, including the terminating \\0
 * character. All %-escaped triplets in @a s are unescaped, for instance, @c
 * "%40%25%23" is copied as @c "@%#". The destination array @a d must be
 * large enough to receive the escaped copy.
 *
 * @param d  destination buffer
 * @param s  string to be copied
 *
 * @return Pointer to the destination buffer.
 */
char *url_unescape(char *d, char const *s)
{
  size_t n = url_unescape_to(d, s, SIZE_MAX);
  if (d)
    d[n] = '\0';
  return d;
}

/** Canonize a URL component */
static
char *url_canonize(char *d, char const *s, size_t n,
		   unsigned syn33,
		   char const allowed[])
{
  unsigned mask32 = 0xbe19003f, mask64 = 0x8000001e, mask96 = 0x8000001d;

  MASKS_WITH_ALLOWED(allowed, mask32, mask64, mask96);

  return url_canonize2(d, s, n, syn33, mask32, mask64, mask96);
}

#define SYN33(c) (1U << (c - 33))
#define IS_SYN33(syn33, c) ((syn33 & (1U << (c - 33))) != 0)

/** Canonize a URL component (with precomputed mask) */
static
char *url_canonize2(char *d, char const * const s, size_t n,
		    unsigned syn33,
		    unsigned m32, unsigned m64, unsigned m96)
{
  size_t i = 0;

  if (d == s)
    for (;s[i] && i < n; d++, i++) 
      if (s[i] == '%')
	break;

  for (;s[i] && i < n; d++, i++) {
    unsigned char c = s[i], h1, h2;

    if (c != '%') {
      if (!IS_SYN33(syn33, c) && IS_EXCLUDED(c, m32, m64, m96))
	return NULL;
      *d = c;
      continue;
    }

    h1 = s[i + 1], h2 = s[i + 2];
    
    if (!IS_HEX(h1) || !IS_HEX(h2)) {
      *d = '\0';
      return NULL;
    }
    
#define UNHEX(a) (a - (a >= 'a' ? 'a' - 10 : (a >= 'A' ? 'A' - 10 : '0')))
    c = (UNHEX(h1) << 4) | UNHEX(h2);

    if (!IS_EXCLUDED(c, m32, m64, m96)) {
      /* Convert hex to normal character */
      *d = c, i += 2;
      continue;
    }

    /* Convert hex to uppercase */
    if (h1 >= 'a' /* && h1 <= 'f' */)
      h1 = h1 - 'a' + 'A';
    if (h2 >= 'a' /* && h2 <= 'f' */)
      h2 = h2 - 'a' + 'A';

    d[0] = '%', d[1] = h1, d[2] = h2;

    d +=2, i += 2;
#undef    UNHEX
  }
  
  *d = '\0';

  return d;
}


/** Canonize a URL component (with precomputed mask).
 *
 * This version does not flag error if *s contains character that should 
 * be escaped.
 */
static
char *url_canonize3(char *d, char const * const s, size_t n,
		    unsigned m32, unsigned m64, unsigned m96)
{
  size_t i = 0;

  if (d == s)
    for (;s[i] && i < n; d++, i++) 
      if (s[i] == '%')
	break;

  for (;s[i] && i < n; d++, i++) {
    unsigned char c = s[i], h1, h2;

    if (c != '%') {
      *d = c;
      continue;
    }

    h1 = s[i + 1], h2 = s[i + 2];
    
    if (!IS_HEX(h1) || !IS_HEX(h2)) {
      *d = '\0';
      return NULL;
    }
    
#define UNHEX(a) (a - (a >= 'a' ? 'a' - 10 : (a >= 'A' ? 'A' - 10 : '0')))
    c = (UNHEX(h1) << 4) | UNHEX(h2);

    if (!IS_EXCLUDED(c, m32, m64, m96)) {
      *d = c, i += 2;
      continue;
    }

    /* Convert hex to uppercase */
    if (h1 >= 'a' /* && h1 <= 'f' */)
      h1 = h1 - 'a' + 'A';
    if (h2 >= 'a' /* && h2 <= 'f' */)
      h2 = h2 - 'a' + 'A';

    d[0] = '%', d[1] = h1, d[2] = h2;

    d +=2, i += 2;
#undef    UNHEX
  }
  
  *d = '\0';

  return d;
}


/** Get URL scheme. */
char const* url_scheme(enum url_type_e url_type)
{
  switch (url_type) {
  case url_any:    return "*";
  case url_sip:    return "sip";
  case url_sips:   return "sips";
  case url_tel:    return "tel";
  case url_fax:    return "fax";
  case url_modem:  return "modem";
  case url_http:   return "http";
  case url_https:  return "https";
  case url_ftp:    return "ftp";
  case url_file:   return "file";
  case url_rtsp:   return "rtsp";
  case url_rtspu:  return "rtspu";
  case url_mailto: return "mailto";
  case url_im:     return "im";
  case url_pres:   return "pres";
  case url_cid:    return "cid";
  case url_msrp:   return "msrp";
  case url_msrps:  return "msrps";
  case url_wv:     return "wv";
  default:       
    assert(url_type == url_unknown);
    return NULL;
  }
}

su_inline
int url_type_is_opaque(enum url_type_e url_type)
{
  return 
    url_type == url_invalid ||
    url_type == url_tel || 
    url_type == url_modem || 
    url_type == url_fax ||
    url_type == url_cid;
}

/** Init an url as given type */
void url_init(url_t *url, enum url_type_e type)
{
  memset(url, 0, sizeof(*url));
  url->url_type = type;
  if (type > url_unknown) {
    char const *scheme = url_scheme(url->url_type);
    if (scheme)
      url->url_scheme = scheme;
  }
}

/** Get url type */
su_inline
enum url_type_e url_get_type(char const *scheme, size_t len)
{
#define test_scheme(s) \
   if (len == strlen(#s) && !strncasecmp(scheme, #s, len)) return url_##s
  
  switch (scheme[0]) {
  case '*': if (strcmp(scheme, "*") == 0) return url_any;
  case 'c': case 'C': 
    test_scheme(cid); break;
  case 'f': case 'F': 
    test_scheme(ftp); test_scheme(file); test_scheme(fax); break;
  case 'h': case 'H': 
    test_scheme(http); test_scheme(https); break;
  case 'i': case 'I': 
    test_scheme(im); break;
  case 'm': case 'M': 
    test_scheme(mailto); test_scheme(modem); 
    test_scheme(msrp); test_scheme(msrps); break;
  case 'p': case 'P': 
    test_scheme(pres); break;
  case 'r': case 'R': 
    test_scheme(rtsp); test_scheme(rtspu); break;
  case 's': case 'S': 
    test_scheme(sip); test_scheme(sips); break;