sip_util.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 sip_util.c
 * 
 * SIP utility functions.
 *
 * @author Pekka Pessi <[e-mail]>.
 *
 * @date Created: Tue Jun 13 02:57:51 2000 ppessi
 */

#include "config.h"

/* Avoid casting sip_t to msg_pub_t and sip_header_t to msg_header_t */
#define MSG_PUB_T       struct sip_s
#define MSG_HDR_T       union sip_header_u

#include <sofia-sip/su_alloc.h>
#include <sofia-sip/su_strlst.h>
#include <sofia-sip/string0.h>

#include "sofia-sip/sip_parser.h"
#include <sofia-sip/sip_header.h>
#include <sofia-sip/sip_util.h>
#include <sofia-sip/sip_status.h>

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


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

/** 
 * Compare two SIP addresses ( @From or @To headers).
 *
 * @retval nonzero if matching.
 * @retval zero if not matching.
 */
int sip_addr_match(sip_addr_t const *a, sip_addr_t const *b)
{
  return
    (a->a_tag == NULL || b->a_tag == NULL || 
     strcmp(a->a_tag, b->a_tag) == 0)
    &&
    str0casecmp(a->a_host, b->a_host) == 0 
    &&
    str0cmp(a->a_user, b->a_user) == 0 
    &&
    str0cmp(a->a_url->url_scheme, b->a_url->url_scheme);
}


/**@ingroup sip_contact
 *
 * Create a contact header.
 *
 * Create a @Contact header object with the given URL and list of parameters.
 *
 * @param home      memory home
 * @param url       URL (string or pointer to url_t)
 * @param p,...     NULL-terminated list of @Contact parameters
 *
 * @return
 * A pointer to newly created @Contact header object when successful or NULL
 * upon an error.
 *
 */
sip_contact_t * sip_contact_create(su_home_t *home,
				   url_string_t const *url,
				   char const *p, ...)
{
  su_strlst_t *l;
  su_home_t *lhome;
  sip_contact_t *m;

  if (url == NULL)
    return NULL;

  l = su_strlst_create_with(NULL, "<", NULL), lhome = su_strlst_home(l);
  if (l == NULL)
    return NULL;

  if (url_is_string(url))
    su_strlst_append(l, (char const *)url);
  else
    su_strlst_append(l, url_as_string(lhome, url->us_url));

  su_strlst_append(l, ">");

  if (p) {
    va_list ap;
    va_start(ap, p);

    for (; p; p = va_arg(ap, char const *)) {
      su_strlst_append(l, ";");
      su_strlst_append(l, p);
    }

    va_end(ap);
  }

  m = sip_contact_make(home, su_strlst_join(l, lhome, ""));

  su_strlst_destroy(l);

  return m;
}

/** Convert a @Via header to @Contact header.
 *
 * The @Contact URI will contain the port number if needed. If transport
 * protocol name starts with "TLS", "SIPS:" URI schema is used. Transport
 * parameter is included in the URI unless the transport protocol is UDP.
 *
 * @param home      memory home
 * @param v         @Via header field structure 
 *                  (with <sent-protocol> and <sent-by> parameters)
 * @param user      username for @Contact URI (may be NULL)
 *
 * @retval contact header structure
 * @retval NULL upon an error
 *
 * @sa sip_contact_create_from_via_with_transport(), 
 *     sip_contact_string_from_via()
 */
sip_contact_t *
sip_contact_create_from_via(su_home_t *home,
			    sip_via_t const *v,
			    char const *user)
{
  const char *tp;

  if (!v) return NULL;

  tp = v->v_protocol;

  if (tp == sip_transport_udp ||
      strcasecmp(tp, sip_transport_udp) == 0)  /* Default is UDP */
    tp = NULL;

  return sip_contact_create_from_via_with_transport(home, v, user, tp);
}

/** Convert a @Via header to @Contact header.
 *
 * The @Contact URI will contain the port number and transport parameters if
 * needed. If transport protocol name starts with "TLS", "SIPS:" URI schema
 * is used.
 *
 * @param home      memory home
 * @param v         @Via header field structure
 *                  (with <sent-by> parameter containing host and port)
 * @param user      username for @Contact URI (may be NULL)
 * @param transport transport name for @Contact URI (may be NULL)
 *
 * @retval contact header structure
 * @retval NULL upon an error
 *
 * @sa sip_contact_create_from_via(), sip_contact_string_from_via()
 */
sip_contact_t *
sip_contact_create_from_via_with_transport(su_home_t *home,
					   sip_via_t const *v,
					   char const *user,
					   char const *transport)
{
  char *s = sip_contact_string_from_via(NULL, v, user, transport);
  sip_contact_t *m = sip_contact_make(home, s);
  su_free(NULL, s);
  return m;
}

/** Convert a @Via header to @Contact URL string.
 *
 * The @Contact URI will contain the port number and transport parameters if
 * needed. If transport protocol name starts with "TLS", "SIPS:" URI schema
 * is used.
 *
 * The contact URI string returned will always have angle brackets ("<" and
 * ">") around it.
 *
 * @param home      memory home
 * @param v         @Via header field structure
 *                  (with <sent-by> parameter containing host and port)
 * @param user      username for @Contact URI (may be NULL)
 * @param transport transport name for @Contact URI (may be NULL)
 *
 * @retval string containing Contact URI with angle brackets
 * @retval NULL upon an error
 */
char *
sip_contact_string_from_via(su_home_t *home,
			    sip_via_t const *v,
			    char const *user,
			    char const *transport)
{
  const char *host, *port, *maddr, *comp;
  char const *scheme = "sip:";
  int one = 1;
  char _transport[16];

  if (!v) return NULL;

  host = v->v_host;
  if (v->v_received)
    host = v->v_received;
  port = sip_via_port(v, &one);
  maddr = v->v_maddr;
  comp = v->v_comp;

  if (host == NULL)
    return NULL;

  if (sip_transport_has_tls(v->v_protocol) ||
      sip_transport_has_tls(transport)) {
    scheme = "sips:";
    if (port && strcmp(port, SIPS_DEFAULT_SERV) == 0)
      port = NULL;
    if (port || host_is_ip_address(host))
      transport = NULL;
  }
  else if (port && strcmp(port, SIP_DEFAULT_SERV) == 0 &&
	   (host_is_ip_address(host) || host_has_domain_invalid(host))) {
    port = NULL;
  }

  if (transport && strncasecmp(transport, "SIP/2.0/", 8) == 0)
    transport += 8;

  /* Make transport parameter lowercase */
  if (transport && strlen(transport) < (sizeof _transport)) {
    char *s = strcpy(_transport, transport);
    short c;

    for (s = _transport; (c = *s) && c != ';'; s++)
      if (isupper(c))
	*s = tolower(c);

    transport = _transport;
  }

  return su_strcat_all(home,
		       "<",
		       scheme,
		       user ? user : "", user ? "@" : "",
		       host,
		       SIP_STRLOG(":", port),
		       SIP_STRLOG(";transport=", transport),
		       SIP_STRLOG(";maddr=", maddr),
		       SIP_STRLOG(";comp=", comp),
		       ">",
		       NULL);
}

/** Check if tranport name refers to TLS */
int sip_transport_has_tls(char const *transport_name)
{
  if (!transport_name)
    return 0;

  if (transport_name == sip_transport_tls)
    return 1;

  /* transport name starts with TLS or SIP/2.0/TLS */
  return
    strncasecmp(transport_name, "TLS", 3) == 0 ||
    strncasecmp(transport_name, sip_transport_tls, 11) == 0;
}

/**Perform sanity check on a SIP message
 * 
 * Check that the SIP message has all the mandatory fields. 
 *
 * @param sip SIP message to be checked
 *
 * @return 
 * When the SIP message fulfills the minimum requirements, return zero,
 * otherwise a negative status code.
 */
int
sip_sanity_check(sip_t const *sip)
{
  if (!sip ||
      !((sip->sip_request != NULL) ^ (sip->sip_status != NULL)) ||
      !sip->sip_to ||
      !sip->sip_from ||
      !sip->sip_call_id ||
      !sip->sip_cseq ||
      !sip->sip_via ||
      (sip->sip_flags & MSG_FLG_TRUNC))
    return -1;  /* Bad request */

  if (sip->sip_request) {
    url_t const *ruri = sip->sip_request->rq_url;

    switch (ruri->url_type) {
    case url_invalid:
      return -1;

    case url_sip: case url_sips: case url_im: case url_pres:
      if (!ruri->url_host || strlen(ruri->url_host) == 0)
	return -1;
      break;

    case url_tel: 
      if (!ruri->url_user || strlen(ruri->url_user) == 0)
	return -1;
      break;
    }

    if (sip->sip_request->rq_method != sip->sip_cseq->cs_method)
      return -1;
    if (sip->sip_request->rq_method == sip_method_unknown &&
	str0casecmp(sip->sip_request->rq_method_name,
		    sip->sip_cseq->cs_method_name))
      return -1;
  }

  return 0;
}

/** Decode a string containg header field.
 *
 * The header object is initialized with the contents of the string. The
 * string is modified when parsing. The home is used to allocate extra
 * memory required when parsing, e.g., for parameter list or when there
 * string contains multiple header fields.
 * 
 * @deprecated
 * Use msg_header_make() or header-specific make functions, e.g.,
 * sip_via_make().
 *
 * @retval 0 when successful
 * @retval -1 upon an error.
 */
issize_t sip_header_field_d(su_home_t *home, sip_header_t *h, char *s, isize_t slen)
{
  if (h && s && s[slen] == '\0') {
    size_t n = span_lws(s);
    s += n; slen -= n;

    for (n = slen; n >= 1 && IS_LWS(s[n - 1]); n--)
      ;
    
    s[n] = '\0';
    
    assert(SIP_HDR_TEST(h));

    return h->sh_class->hc_parse(home, h, s, slen);
  }
  else
    return -1;
}

/** Encode a SIP header contents.
 *
 * @deprecated Use msg_header_field_e() instead.
 */
issize_t sip_header_field_e(char *b, isize_t bsiz, sip_header_t const *h, int flags)
{
  return msg_header_field_e(b, bsiz, h, flags);
}

/** Convert the header @a h to a string allocated from @a home. */
char *sip_header_as_string(su_home_t *home, sip_header_t const *h)
{
  ssize_t len;
  char *rv, s[128];

  if (h == NULL)
    return NULL;

  len = sip_header_field_e(s, sizeof(s), h, 0);

  if (len >= 0 && (size_t)len < sizeof(s))
    return su_strdup(home, s);

  if (len == -1)
    len = 2 * sizeof(s);
  else
    len += 1;

  for (rv = su_alloc(home, len);
       rv;
       rv = su_realloc(home, rv, len)) {
    ssize_t n = sip_header_field_e(rv, len, h, 0);
    if (n > -1 && n + 1 <= len)
      break;
    if (n > -1)			/* glibc >2.1 */
      len = n + 1;		
    else			/* glibc 2.0 */
      len *= 2;			
  }

  return rv;
}

/** Calculate size of a SIP header. */
isize_t sip_header_size(sip_header_t const *h)
{
  assert(h == NULL || h == SIP_NONE || h->sh_class);
  if (h == NULL || h == SIP_NONE)
    return 0;
  else
    return h->sh_class->hc_dxtra(h, h->sh_class->hc_size);
}

/** Duplicate a url or make a url out of string. 
 * @deprecated Use url_hdup() instead.
 */
url_t *sip_url_dup(su_home_t *home, url_t const *o)
{
  return url_hdup(home, o);
}

/**Calculate Q value.
 * 
 * Convert q-value string @a q to numeric value
 * in range (0..1000).  Q values are used, for instance, to describe
 * relative priorities of registered contacts.
 *
 * @param q q-value string <code>("1" | "." 1,3DIGIT)</code>
 * 
 * @return An integer in range 0 .. 1000.
 */
unsigned sip_q_value(char const *q)
{
  unsigned value = 0;

  if (!q)
    return 1000;
  if (q[0] != '0' && q[0] != '.' && q[0] != '1')
    return 500; /* Garbage... */
  while (q[0] == '0')
    q++;
  if (q[0] >= '1' && q[0] <= '9')
    return 1000;
  if (q[0] == '\0')
    return 0;
  if (q[0] != '.')      
    return 500;    /* Garbage... */

  if (q[1] >= '0' && q[1] <= '9') {
    value = (q[1] - '0') * 100;