outbound.c

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

  return 0;
}


/** @internal Check if there is a NAT between us and registrar.
 *
 * @retval -1 upon an error
 * @retval #ob_register_ok (0) if the registration was OK
 * @retval #ob_reregister (1) if client needs to re-register
 * @retval #ob_reregister_now (2) if client needs to re-register immediately
 */
static
int outbound_check_for_nat(outbound_t *ob,
			   sip_t const *request,
			   sip_t const *response)
{
  int binding_changed;
  sip_contact_t *m = ob->ob_rcontact;

  /* Update NAT information */
  binding_changed = outbound_nat_detect(ob, request, response);

  if (!ob->ob_nat_detected)
    return ob_no_nat;

  /* Contact was set by application, do not change it */
  if (!ob->ob_by_stack)
    return ob_no_nat;

  /* Application does not want us to do any NAT traversal */ 
  if (!ob->ob_prefs.natify)
    return ob_no_nat;

  /* We have detected NAT. Now, what to do?
   * 1) do nothing - register as usual and let proxy take care of it?
   * 2) try to detect our public nat binding and use it
   * 2A) use public vias from nta generated by STUN or UPnP
   * 2B) use SIP Via header
   */

  /* Do we have to ask for reregistration */
  if (!m || binding_changed >= ob_nat_changed) {
    if (ob->ob_stun) {
      /* Use STUN? */
      return ob_reregister;
    }
    else if (ob->ob_upnp) {
      /* Use UPnP */
      return ob_reregister;
    }
    else {
      if (outbound_contacts_from_via(ob, response->sip_via) < 0)
        return -1;
    }

    return ob_reregister_now;
  }

  return 0;
}

/**@internal
 *
 * Detect NAT.
 *
 * Based on "received" and possible "rport" parameters in the top-most Via,
 * check and update our NAT status.
 *
 * @retval ob_nat_changed (2) change in public NAT binding detected
 * @retval ob_nat_detected (1) NAT binding detected
 * @retval ob_no_nat (0) no NAT binding detected
 * @retval -1 an error occurred
 */
static
int outbound_nat_detect(outbound_t *ob,
			sip_t const *request,
			sip_t const *response)
{
  sip_via_t const *v;
  int one = 1;
  char const *received, *rport;
  char *nat_detected, *nat_port;
  char *new_detected, *new_port;

  assert(request && request->sip_request);
  assert(response && response->sip_status);

  if (!ob || !response || !response->sip_via || !request->sip_via)
    return -1;

  v = response->sip_via;

  received = v->v_received;
  if (!received || !strcmp(received, request->sip_via->v_host))
    return 0;

  if (!host_is_ip_address(received)) {
    if (received[0])
      SU_DEBUG_3(("outbound(%p): Via with invalid received=%s\n",
		  (void *)ob->ob_owner, received));
    return 0;
  }

  rport = sip_via_port(v, &one); assert(rport);

  nat_detected = ob->ob_nat_detected;
  nat_port = ob->ob_nat_port;

  if (nat_detected && host_cmp(received, nat_detected) == 0) {
    if (nat_port && strcasecmp(rport, nat_port) == 0)
      return 1;
    if (!v->v_rport || !v->v_rport[0])
      return 1;
  }

  if (!nat_detected) {
    SU_DEBUG_5(("outbound(%p): detected NAT: %s != %s\n",
		(void *)ob->ob_owner, v->v_host, received));
    if (ob->ob_oo && ob->ob_oo->oo_status)
      ob->ob_oo->oo_status(ob->ob_owner, ob, 101, "NAT detected", TAG_END());
  }
  else {
    SU_DEBUG_5(("outbound(%p): NAT binding changed: "
		"[%s]:%s != [%s]:%s\n",
		(void *)ob->ob_owner, nat_detected, nat_port, received, rport));
    if (ob->ob_oo && ob->ob_oo->oo_status)
      ob->ob_oo->oo_status(ob->ob_owner, ob, 102, "NAT binding changed", TAG_END());
  }

  /* Save our nat binding */
  new_detected = su_strdup(ob->ob_home, received);
  new_port = su_strdup(ob->ob_home, rport);

  if (!new_detected || !new_port) {
    su_free(ob->ob_home, new_detected);
    su_free(ob->ob_home, new_port);
    return -1;
  }

  ob->ob_nat_detected = new_detected;
  ob->ob_nat_port = new_port;

  su_free(ob->ob_home, nat_detected);
  su_free(ob->ob_home, nat_port);

  return 2;
}

/* ---------------------------------------------------------------------- */

/** Convert "gruu" parameter returned by registrar to Contact header. */
int outbound_gruuize(outbound_t *ob, sip_t const *sip)
{
  sip_contact_t *m = NULL;
  char *gruu;

  if (!ob)
    return 0;

  if (ob->ob_rcontact == NULL)
    return -1;

  if (!ob->ob_prefs.gruuize && ob->ob_instance) {
    char const *my_instance, *my_reg_id = NULL;
    char const *instance, *reg_id;

    m = ob->ob_rcontact;
    my_instance = msg_header_find_param(m->m_common, "+sip.instance=");
    if (my_instance)
      my_reg_id = msg_header_find_param(m->m_common, "reg-id=");

    for (m = sip->sip_contact; m; m = m->m_next) {
      if (my_instance) {
	instance = msg_header_find_param(m->m_common, "+sip.instance=");
	if (!instance || strcmp(instance, my_instance))
	  continue;
	if (my_reg_id) {
	  reg_id = msg_header_find_param(m->m_common, "reg-id=");
	  if (!reg_id || strcmp(reg_id, my_reg_id))
	    continue;
	}
      }

      if (url_cmp_all(ob->ob_rcontact->m_url, m->m_url) == 0)
	break;
    }
  }

  if (m == NULL) {
    if (ob->ob_gruu)
      msg_header_free(ob->ob_home, (void *)ob->ob_gruu), ob->ob_gruu = NULL;
    return 0;
  }

  gruu = (char *)msg_header_find_param(m->m_common, "pub-gruu=");
  
  if (gruu == NULL || gruu[0] == '\0')
    gruu = (char *)msg_header_find_param(m->m_common, "gruu=");

  if (gruu == NULL || gruu[0] == '\0')
    return 0;

  gruu = msg_unquote_dup(NULL, gruu);
  m = gruu ? sip_contact_format(ob->ob_home, "<%s>", gruu) : NULL;
  su_free(NULL, gruu);

  if (!m)
    return -1;

  if (ob->ob_gruu)
    msg_header_free(ob->ob_home, (void *)ob->ob_gruu);
  ob->ob_gruu = m;

  return 0;
}

/* ---------------------------------------------------------------------- */

static int create_keepalive_message(outbound_t *ob,
				    sip_t const *register_request);

static int keepalive_options(outbound_t *ob);
static int keepalive_options_with_registration_probe(outbound_t *ob);

static int response_to_keepalive_options(outbound_t *ob,
					 nta_outgoing_t *orq,
					 sip_t const *sip);

static void keepalive_timer(su_root_magic_t *root_magic,
			    su_timer_t *t,
			    su_timer_arg_t *ob_as_timer_arg);

/** Start OPTIONS keepalive or contact validation process */
void outbound_start_keepalive(outbound_t *ob,
			      nta_outgoing_t *register_transaction)
{
  unsigned interval = 0;
  int need_to_validate;

  if (!ob)
    return;

  if (ob->ob_prefs.natify && ob->ob_prefs.okeepalive)
    interval = ob->ob_prefs.interval;
  need_to_validate = ob->ob_prefs.validate && !ob->ob_validated;

  if (!ob->ob_nat_detected || !register_transaction ||
      !(need_to_validate || interval != 0)) {
    outbound_stop_keepalive(ob);
    return;
  }

  if (ob->ob_keepalive.timer)
    su_timer_destroy(ob->ob_keepalive.timer), ob->ob_keepalive.timer = NULL;

  if (interval)
    ob->ob_keepalive.timer =
      su_timer_create(su_root_task(ob->ob_root), interval);

  ob->ob_keepalive.interval = interval;

  if (!ob->ob_validated && ob->ob_keepalive.sipstun 
      && 0 /* Stun is disabled for now */) {
    nta_tport_keepalive(register_transaction);
  }
  else {
    if (register_transaction) {
      msg_t *msg = nta_outgoing_getrequest(register_transaction);
      sip_t const *register_request = sip_object(msg);
      create_keepalive_message(ob, register_request);
      msg_destroy(msg);
    }

    keepalive_options(ob);
  }
}

void outbound_stop_keepalive(outbound_t *ob)
{
  if (!ob)
    return;

  ob->ob_keepalive.interval = 0;

  if (ob->ob_keepalive.timer)
    su_timer_destroy(ob->ob_keepalive.timer), ob->ob_keepalive.timer = NULL;

  if (ob->ob_keepalive.orq)
    nta_outgoing_destroy(ob->ob_keepalive.orq), ob->ob_keepalive.orq = NULL;

  if (ob->ob_keepalive.msg)
    msg_destroy(ob->ob_keepalive.msg), ob->ob_keepalive.msg = NULL;
}

/** @internal Create a message template for keepalive. */
static int create_keepalive_message(outbound_t *ob, sip_t const *regsip)
{
  msg_t *msg = nta_msg_create(ob->ob_nta, MSG_FLG_COMPACT), *previous;
  sip_t *osip = sip_object(msg);
  sip_contact_t *m = ob->ob_rcontact;

  unsigned d = ob->ob_keepalive.interval;

  if (msg == NULL)
    return -1;

  assert(regsip); assert(regsip->sip_request);

  if (m && m->m_params) {
    sip_accept_contact_t *ac;
    size_t i;
    int features = 0;

    ac = sip_accept_contact_make(msg_home(msg), "*;require;explicit");

    for (i = 0; m->m_params[i]; i++) {
      char const *s = m->m_params[i];
      if (!sip_is_callerpref(s))
	continue;
      features++;
      s = su_strdup(msg_home(msg), s);
      msg_header_add_param(msg_home(msg), ac->cp_common, s);
    }
    
    if (features)
      msg_header_insert(msg, NULL, (void *)ac);
    else
      msg_header_free(msg_home(msg), (void *)ac);
  }

  if (0 >
      /* Duplicate essential headers from REGISTER request: */
      sip_add_tl(msg, osip,
		 SIPTAG_TO(regsip->sip_to),
		 SIPTAG_FROM(regsip->sip_from),
		 /* XXX - we should only use loose routing here */
		 /* XXX - if we used strict routing,
		    the route header/request_uri must be restored
		 */
		 SIPTAG_ROUTE(regsip->sip_route),
		 /* Add Max-Forwards 0 */
		 TAG_IF(d, SIPTAG_MAX_FORWARDS_STR("0")),
		 TAG_IF(d, SIPTAG_SUBJECT_STR("KEEPALIVE")),
		 SIPTAG_CALL_ID_STR(ob->ob_cookie),
		 SIPTAG_ACCEPT_STR(outbound_content_type),
		 TAG_END()) ||
      /* Create request-line, Call-ID, CSeq */
      nta_msg_request_complete(msg,
       			nta_default_leg(ob->ob_nta),
       			SIP_METHOD_OPTIONS,
       			(void *)regsip->sip_to->a_url) < 0 ||
      msg_serialize(msg, (void *)osip) < 0 ||
      msg_prepare(msg) < 0)
    return msg_destroy(msg), -1;

  previous = ob->ob_keepalive.msg;
  ob->ob_keepalive.msg = msg;
  msg_destroy(previous);

  return 0;
}

static int keepalive_options(outbound_t *ob)
{
  msg_t *req;
  sip_t *sip;

  if (ob->ob_keepalive.orq)
    return 0;

  if (ob->ob_prefs.validate && ob->ob_registered && !ob->ob_validated)
    return keepalive_options_with_registration_probe(ob);

  req = msg_copy(ob->ob_keepalive.msg);
  if (!req)
    return -1;
  sip = sip_object(req); assert(sip); assert(sip->sip_request);

  if (nta_msg_request_complete(req, nta_default_leg(ob->ob_nta),
			       SIP_METHOD_UNKNOWN, NULL) < 0)
    return msg_destroy(req), -1;

  if (ob->ob_keepalive.auc[0])
    auc_authorization(ob->ob_keepalive.auc, req, (void *)sip,
		      "OPTIONS", sip->sip_request->rq_url, sip->sip_payload);

  ob->ob_keepalive.orq =
    nta_outgoing_mcreate(ob->ob_nta,
			 response_to_keepalive_options,
			 ob,
			 NULL,
			 req,
			 TAG_IF(ob->ob_proxy_override,
				NTATAG_DEFAULT_PROXY(ob->ob_proxy)),
			 TAG_END());

  if (!ob->ob_keepalive.orq)
    return msg_destroy(req), -1;

  return 0;
}

static int response_to_keepalive_options(outbound_t *ob,
					 nta_outgoing_t *orq,
					 sip_t const *sip)
{
  int status = 408;
  char const *phrase = sip_408_Request_timeout;
  int binding_check;
  int challenged = 0, credentials = 0;
  msg_t *_reqmsg = nta_outgoing_getrequest(orq);
  sip_t *request = sip_object(_reqmsg); msg_destroy(_reqmsg);

  if (sip && sip->sip_status) {
    status = sip->sip_status->st_status;
    phrase = sip->sip_status->st_phrase;
  }

  if (status == 100) {
    /* This probably means that we are in trouble. whattodo, whattodo */