sip_util.c

sip协议栈

  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;
    if (q[2] >= '0' && q[2] <= '9') {
      value += (q[2] - '0') * 10;
      if (q[3] >= '0' && q[3] <= '9') {
	value += (q[3] - '0');
	if (q[4] > '5' && q[4] <= '9')
	  /* Round upwards */
	  value += 1;
	else if (q[4] == '5') 
	  value += value & 1; /* Round to even */
      }
    }
  }

  return value;
}


/**@ingroup sip_route
 *
 * Get first route header and remove it from its fragment chain. 
 *
 */
sip_route_t *sip_route_remove(msg_t *msg, sip_t *sip)
{
  sip_route_t *r;

  if ((r = sip->sip_route))
    msg_header_remove(msg, (msg_pub_t *)sip, (msg_header_t *)r);

  return r;
}

/**@ingroup sip_route
 *
 * Get last route header and remove it from its fragment chain. 
 *
 */
sip_route_t *sip_route_pop(msg_t *msg, sip_t *sip)
{
  sip_route_t *r;

  for (r = sip->sip_route; r; r = r->r_next) 
    if (r->r_next == NULL) {
      msg_header_remove(msg, (msg_pub_t *)sip, (msg_header_t *)r);
      return r;
    }

  return NULL;
}


/**@ingroup sip_route
 *
 * Get first route header and rewrite the RequestURI. 
 */
sip_route_t *sip_route_follow(msg_t *msg, sip_t *sip)
{
  if (sip->sip_route) {
    /* XXX - in case of outbound proxy, route may contain our address */ 
      
    sip_route_t *r = sip_route_remove(msg, sip);
    sip_request_t *rq = sip->sip_request;

    rq = sip_request_create(msg_home(msg), rq->rq_method, rq->rq_method_name,
			    (url_string_t const *)r->r_url, rq->rq_version);
    url_strip_transport(rq->rq_url);

    msg_header_insert(msg, (msg_pub_t *)sip, (msg_header_t *)rq);

    return r;
  }
  return NULL;
}

/**@ingroup sip_route
 * 
 * Check if route header has lr param.
 *
 * "lr" param can be either URL or header parameter.
 */
int 
sip_route_is_loose(sip_route_t const *r)
{
  if (!r)
    return 0;
  if (r->r_url->url_params)
    return url_has_param(r->r_url, "lr");
  else
    return r->r_params && msg_params_find(r->r_params, "lr") != NULL;
}

/**@ingroup sip_route
 *
 * Reverse a route header. 
 *
 * The function sip_route_reverse() reverses a route header like @b
 * Record-Route or @b Path.
 */
sip_route_t *sip_route_reverse(su_home_t *home, sip_route_t const *route)
{
  sip_route_t *reverse = NULL;
  sip_route_t r[1], *tmp;
  sip_route_init(r);

  for (reverse = NULL; route; route = route->r_next) {
    *r->r_url = *route->r_url;
    /* Fix broken (Record-)Routes without <> */
    if (r->r_url->url_params == NULL
	&& r->r_params 
	&& r->r_params[0] 
	&& (r->r_params[0][0] == 'l' || r->r_params[0][0] == 'L')
	&& (r->r_params[0][1] == 'r' || r->r_params[0][1] == 'R')
	&& (r->r_params[0][2] == '=' || r->r_params[0][2] == 0))
      r->r_url->url_params = route->r_params[0],
	r->r_params = route->r_params + 1;
    else
      r->r_params = route->r_params;
    tmp = sip_route_dup(home, r);
    if (!tmp) 
      goto error;
    tmp->r_next = reverse;
    reverse = tmp;
  }

  return reverse;

 error:
  while (reverse) {
    sip_route_t *r_next = reverse->r_next;
    su_free(home, reverse);
    reverse = r_next;
  }

  return NULL;
}


/**@ingroup sip_route
 *
 * Fix and duplicate a route header. 
 *
 * The function sip_route_reverse() reverses a route header like @b
 * Record-Route or @b Path.
 *
 */
sip_route_t *sip_route_fixdup(su_home_t *home, sip_route_t const *route)
{
  sip_route_t *copy = NULL;
  sip_route_t r[1], **rr;
  sip_route_init(r);

  /* Copy the record route as route */
  for (rr = &copy; route; route = route->r_next) {
    *r->r_url = *route->r_url;
    /* Fix broken (Record-)Routes without <> */
    if (r->r_url->url_params == NULL
	&& r->r_params 
	&& r->r_params[0] 
	&& (r->r_params[0][0] == 'l' || r->r_params[0][0] == 'L')
	&& (r->r_params[0][1] == 'r' || r->r_params[0][1] == 'R')
	&& (r->r_params[0][2] == '=' || r->r_params[0][2] == 0))
      r->r_url->url_params = route->r_params[0],
	r->r_params = route->r_params + 1;
    else
      r->r_params = route->r_params;
    *rr = sip_route_dup(home, r);
    if (!*rr) goto error;
    rr = &(*rr)->r_next;
  }

  return copy;

 error:
  while (copy) {
    sip_route_t *r_next = copy->r_next;
    su_free(home, copy);
    copy = r_next;
  }

  return NULL;
}

static void sip_fragment_clear_chain(sip_header_t *h)
{
  void const *next;

  for (h = h; h; h = h->sh_succ) {
    next = (char *)h->sh_data + h->sh_len;

    sip_fragment_clear(h->sh_common);

    if (!next ||
	!h->sh_succ ||
	h->sh_next != h->sh_succ ||
	h->sh_succ->sh_data != next ||
	h->sh_succ->sh_len)
      return;
  }
}

/**@ingroup sip_route
 *
 * Fix Route header.
 */
sip_route_t *sip_route_fix(sip_route_t *route)
{
  sip_route_t *r;
  sip_header_t *h = NULL;
  int i;

  for (r = route; r; r = r->r_next) {
    /* Keep track of first header structure on this header line */
    if (!h 
	|| (char *)h->sh_data + h->sh_len != r->r_common->h_data
	|| r->r_common->h_len)
      h = (sip_header_t *)r;

    if (r->r_url->url_params == NULL
	&& r->r_params 
	&& r->r_params[0] 
	&& (r->r_params[0][0] == 'l' || r->r_params[0][0] == 'L')
	&& (r->r_params[0][1] == 'r' || r->r_params[0][1] == 'R')
	&& (r->r_params[0][2] == '=' || r->r_params[0][2] == 0)) {
      r->r_url->url_params = r->r_params[0];

      for (i = 0; r->r_params[i]; i++)
	((char const **)r->r_params)[i] = r->r_params[i + 1];

      sip_fragment_clear_chain(h);
    }
  }

  return route;
}

/**@ingroup sip_via
 *
 * Get first via header and remove it from its fragment chain. 
 */
sip_via_t *sip_via_remove(msg_t *msg, sip_t *sip)
{
  sip_via_t *v;

  if (sip == NULL)
    return NULL;
  
  for (v = sip->sip_via; v; v = v->v_next) {
    sip_fragment_clear(v->v_common);

    if (v->v_next != (void *)v->v_common->h_succ)
      break;
  }

  if ((v = sip->sip_via))
    msg_header_remove(msg, (msg_pub_t *)sip, (msg_header_t *)v);

  return v;
}

/** Serialize payload.
 *
 * The sip_payload_serialize() adds missing headers to MIME multiparty payload,
 * encodes them and orders them in header chain.  It also calculates the total
 * length of the payload.
 */
unsigned long sip_payload_serialize(msg_t *msg, sip_payload_t *pl)
{
  unsigned long total;

  for (total = 0; pl; pl = (sip_payload_t *)pl->pl_next) {
    total += (unsigned)pl->pl_common->h_len;
  }

  return total;
}

/** 
 * Remove extra parameters from an AOR URL.
 *
 * The extra parameters listed in the RFC 3261 table 1 include port number,
 * method, maddr, ttl, transport, lr and headers.
 * 
 * @note The funtion modifies the @a url and the strings attached to it.
 *
 * @retval 0 when successful
 * @retval -1 upon an error
 */
int sip_aor_strip(url_t *url)
{
  if (url == NULL)
    return -1;

  url->url_port = NULL;
  url->url_headers = NULL;

  if (url->url_params) {
    char *d, *s;
    size_t n;
    int semi;

#   define PARAM_MATCH(s, tag)						\
    (strncasecmp(s, tag, strlen(tag)) == 0 &&				\
     (s[strlen(tag)] == '\0' ||						\
      s[strlen(tag)] == ';' ||						\
      s[strlen(tag)] == '='))

    for (d = s = (char *)url->url_params; *s; s += n + semi) {
      n = strcspn(s, ";");
      semi = s[n] != '\0';
    
      if (PARAM_MATCH(s, "method"))
	continue;
      if (PARAM_MATCH(s, "maddr"))
	continue;
      if (PARAM_MATCH(s, "ttl"))
	continue;
      if (PARAM_MATCH(s, "transport"))
	continue;
      if (PARAM_MATCH(s, "lr"))
	continue;

      if (s != d) {
	if (d != url->url_params)
	  d++;
	if (s != d)
	  memcpy(d, s, n + 1);
      }
      d += n;
    }

    if (d == url->url_params)
      url->url_params = NULL;
    else if (d != s)
      *d = '\0';

#   undef PARAM_MATCH
  }

  return 0;
}

/** Compare Security-Verify header with Security-Server header. */
int sip_security_verify_compare(sip_security_server_t const *s,
				sip_security_verify_t const *v,
				msg_param_t *return_d_ver)
{
  int i, j, retval, digest;
  msg_param_t const *s_params, *v_params, empty[] = { NULL };

  if (return_d_ver)
    *return_d_ver = NULL;

  if (s == NULL)
    return 0;

  for (;;s = s->sa_next, v = v->sa_next) {
    if (s == NULL || v == NULL)
      return (s == NULL) - (v == NULL);
    
    if ((retval = str0cmp(s->sa_mec, v->sa_mec)))
      return retval;

    digest = strcasecmp(s->sa_mec, "Digest") == 0;

    s_params = s->sa_params, v_params = v->sa_params;

    if (digest && s_params == NULL && v_params != NULL)
      s_params = empty;

    if (s_params == NULL || v_params == NULL) {
      if ((retval = (s_params == NULL) - (v_params == NULL)))
	return retval;
      continue;
    }

    for (i = 0, j = 0;; i++, j++) {
      if (digest && v_params[j] && 
	  strncasecmp(v_params[j], "d-ver=", 6) == 0) {
	if (return_d_ver)
	  *return_d_ver = v_params[j] + strlen("d-ver=");
	j++;
      }

      retval = str0cmp(s_params[i], v_params[j]);
      
      if (retval || s_params[i] == NULL || v_params[j] == NULL) 
	break;
    }

    if (retval)
      return retval;
  }
}

/** Select best mechanism from Security-Client header. 
 *
 * @note We assume that Security-Server header in @a s is sorted by
 * preference.
 */
sip_security_client_t const *
sip_security_client_select(sip_security_client_t const *client,
			   sip_security_server_t const *server)
{
  sip_security_server_t const *c, *s;

  if (server == NULL || client == NULL)
    return NULL;

  for (s = server; s; s = s->sa_next) {
    for (c = client; c; c = c->sa_next) {
      if (str0cmp(s->sa_mec, c->sa_mec) == 0)
	return c;
    }
  }

  return NULL;
}

/**Checks if the response with given response code terminates dialog or
 * dialog usage.
 * 
 * @return -1 if the response with given code terminates whole dialog.
 * @return 1 if the response terminates the dialog usage.
 * @return 0 if the response does not terminate dialog or dialog usage.
 * 
 * @return
 * The @a *return_graceful_terminate_usage is set to 1, if application
 * should gracefully terminate its dialog usage. It is set to 0, if no
 * graceful terminate is required. If it is up to application policy to
 * decide whether to gracefully terminate or not, the
 * @a *return_graceful_terminate_usage is left unmodified.
 *
 * @sa 
 * http://www.ietf.org/internet-drafts/draft-sparks-sipping-dialogusage-01.txt
 */
int sip_response_terminates_dialog(int response_code,
				   sip_method_t method,
				   int *return_graceful_terminate_usage)
{
  enum { no_effect, terminate_usage = 1, terminate_dialog = -1 };
  int dummy;

  if (!return_graceful_terminate_usage) 
    return_graceful_terminate_usage = &dummy;

  if (response_code < 300)
    return *return_graceful_terminate_usage = 0;

  /*  
      3xx responses: Redirection mid-dialog is not well understood in SIP,
      but whatever effect it has impacts the entire dialog and all of