nua_notifier.c

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

static
int nua_subscribe_server_report(nua_server_request_t *sr, tagi_t const *tags)
{
  nua_handle_t *nh = sr->sr_owner;
  nua_dialog_state_t *ds = nh->nh_ds;
  nua_dialog_usage_t *du = sr->sr_usage;
  struct notifier_usage *nu = nua_dialog_usage_private(du);
  enum nua_substate substate = nua_substate_terminated;
  int notify = 0;
  int retval;

  if (nu && !sr->sr_terminating) {
    substate = nu->nu_substate;
  }

  /* nu_requested is set by SUBSCRIBE and cleared when NOTIFY is sent */
  if (nu && nu->nu_requested && substate != nua_substate_embryonic) {
#if SU_HAVE_EXPERIMENTAL
    sip_t const *sip = sr->sr_request.sip;
    sip_suppress_notify_if_match_t *snim = sip_suppress_notify_if_match(sip);
    sip_suppress_body_if_match_t *sbim = sip_suppress_body_if_match(sip);
    
    if (!nu->nu_tag)
      notify = 1;
    else if (snim && !strcasecmp(snim->snim_tag, nu->nu_tag))
      notify = 0;
    else if (sbim && !strcasecmp(snim->snim_tag, nu->nu_tag))
      notify = 1, nu->nu_no_body = 1;
    else 
#endif
      notify = 1;

    notify = notify && du->du_cr != NULL;
  }

  retval = nua_base_server_treport(sr, NUTAG_SUBSTATE(substate), TAG_END());

  if (retval >= 2 || du == NULL)
    return retval;
  
  if (notify) {
    /* Send NOTIFY (and terminate subscription, when needed) */
    nua_dialog_usage_refresh(nh, ds, du, sip_now());
  }
  
  return retval;
}

/* ======================================================================== */
/* NOTIFY client */

/**@fn void nua_notify(nua_handle_t *nh, tag_type_t tag, tag_value_t value, ...);
 *
 * Send a SIP NOTIFY request message.
 *
 * This function is used when the application implements itself the
 * notifier. The application must provide valid @SubscriptionState and
 * @Event headers using SIP tags. The subscription state can be modified
 * with NUTAG_SUBSTATE(), however, its effect is overriden by
 * @SubscriptionState header included in the nua_notify() tags.
 *
 * @bug If the @Event is not given by application, stack uses the @Event
 * header from the first subscription usage on handle.
 * 
 * If there is no active <i>notifier dialog usage</i> or no notifier dialog
 * usage matches the @Event header given by the application the nua_notify()
 * request is rejected locally by the stack with status code 481. The local
 * rejection can be bypassed if NUTAG_NEWSUB(1) is included in tags.
 *
 * Please note that including NUTAG_NEWSUB(1) in nua_notify() tags if there
 * is a valid subscription may lead to an extra NOTIFY sent to subscriber if
 * the subscription had been terminated by the subscriber or by a timeout
 * before the nua_notify() is processed.
 *
 * @param nh              Pointer to operation handle
 * @param tag, value, ... List of tagged parameters
 *
 * @return 
 *    nothing
 *
 * @par Related Tags:
 *    NUTAG_SUBSTATE() \n
 *    NUTAG_NEWSUB() \n
 *    Tags of nua_set_hparams() \n
 *    Header tags defined in <sofia-sip/sip_tag.h>
 *
 * @par Events:
 *    #nua_r_notify
 *
 * @sa @RFC3265, #nua_i_subscribe, #nua_i_refer, NUTAG_ALLOW_EVENTS()
 */

static int nua_notify_client_init(nua_client_request_t *cr, 
				  msg_t *, sip_t *,
				  tagi_t const *tags);
static int nua_notify_client_init_etag(nua_client_request_t *cr,
				       msg_t *msg, sip_t *sip,
				       tagi_t const *tags);
static int nua_notify_client_request(nua_client_request_t *cr,
				     msg_t *, sip_t *,
				     tagi_t const *tags);
static int nua_notify_client_report(nua_client_request_t *cr,
				    int status, char const *phrase,
				    sip_t const *sip,
				    nta_outgoing_t *orq,
				    tagi_t const *tags);

static nua_client_methods_t const nua_notify_client_methods = {
  SIP_METHOD_NOTIFY,		/* crm_method, crm_method_name */
  0,				/* crm_extra */
  {				/* crm_flags */
    /* create_dialog */ 1,
    /* in_dialog */ 1,
    /* target refresh */ 1
  },
  NULL,				/* crm_template */
  nua_notify_client_init,	/* crm_init */
  nua_notify_client_request,	/* crm_send */
  NULL,				/* crm_check_restart */
  NULL,				/* crm_recv */
  NULL,				/* crm_preliminary */
  nua_notify_client_report,	/* crm_report */
  NULL,				/* crm_complete */
};

/**@internal Send NOTIFY. */
int nua_stack_notify(nua_t *nua,
		     nua_handle_t *nh,
		     nua_event_t e,
		     tagi_t const *tags)
{
  return nua_client_create(nh, e, &nua_notify_client_methods, tags);
}

static int nua_notify_client_init(nua_client_request_t *cr,
				  msg_t *msg, sip_t *sip,
				  tagi_t const *tags)
{
  nua_handle_t *nh = cr->cr_owner;
  nua_dialog_usage_t *du;
  struct notifier_usage *nu;
  sip_event_t const *o = sip->sip_event;
  sip_subscription_state_t *ss = sip->sip_subscription_state;
  sip_time_t now = sip_now();
    
  if (o == NULL && nh->nh_ds->ds_has_notifys == 1)
    o = NONE;

  du = nua_dialog_usage_get(nh->nh_ds, nua_notify_usage, o);

  if (!du) {
    tagi_t const *newsub = tl_find_last(tags, nutag_newsub);

    if (!newsub || !newsub->t_value)
      return 0; /* Rejected eventually by nua_notify_client_request() */

    /* Create new notifier */
    du = nua_dialog_usage_add(nh, nh->nh_ds, nua_notify_usage, o);
    if (du == NULL)
      return -1;

    nu = nua_dialog_usage_private(du);
    nu->nu_expires = now;
  }
  else
    nu = nua_dialog_usage_private(du);


  if (nu->nu_substate == nua_substate_terminated) {
    /*Xyzzy*/;
  }
  else if (ss != NULL) {
    /* SIPTAG_SUBSCRIPTION_STATE() overrides NUTAG_SUBSTATE() */
    nu->nu_substate = nua_substate_make(ss->ss_substate);

    if (ss->ss_expires) {
      unsigned long expires = strtoul(ss->ss_expires, NULL, 10);
      if (now + expires < now)
	expires = SIP_TIME_MAX - now - 1;

      /* We can change the lifetime of unsolicited subscription at will */
      if (nu->nu_requested == 0)
	nu->nu_expires = nu->nu_requested = now + expires;
      /* Notifier can only shorten the subscribed time */ 
      else if (nu->nu_requested >= now + expires)
	nu->nu_expires = nu->nu_requested = now + expires;
    }
    else {
      if (nu->nu_requested >= nu->nu_expires)
	nu->nu_expires = nu->nu_requested;
    }

  }
  else {
    enum nua_substate substate = nu->nu_substate;

    if (nu->nu_requested >= nu->nu_expires)
      nu->nu_expires = nu->nu_requested;

    if (nu->nu_expires > now) {
      tagi_t const *t = tl_find_last(tags, nutag_substate);
      if (t)
        substate = (enum nua_substate)t->t_value;
    }
    else
      substate = nua_substate_terminated;

    switch (substate) {
    case nua_substate_embryonic:
      /*FALLTHROUGH*/
    case nua_substate_pending:
      nu->nu_substate = nua_substate_pending;
      break;
    case nua_substate_active:
    default:
      nu->nu_substate = nua_substate_active;
      break;
    case nua_substate_terminated:
      nu->nu_substate = nua_substate_terminated;
      break;
    }
  }

  cr->cr_usage = du;

  return nua_notify_client_init_etag(cr, msg, sip, tags);
}

static int nua_notify_client_init_etag(nua_client_request_t *cr,
				       msg_t *msg, sip_t *sip,
				       tagi_t const *tags)
{
#if SU_HAVE_EXPERIMENTAL
  nua_handle_t *nh = cr->cr_owner;
  struct notifier_usage *nu = nua_dialog_usage_private(cr->cr_usage);
  nua_server_request_t *sr;

  if (nu->nu_tag)
    su_free(nh->nh_home, nu->nu_tag), nu->nu_tag = NULL;
    nu->nu_no_body = 0;

  if (sip->sip_etag) {
    nu->nu_appl_etags = 1;
    nu->nu_tag = su_strdup(nh->nh_home, sip->sip_etag->g_string);
  }
  else if (!nu->nu_appl_etags && nu->nu_etags) {
    su_md5_t md5[1];
    unsigned char digest[SU_MD5_DIGEST_SIZE];
    sip_payload_t pl[1] = { SIP_PAYLOAD_INIT() };
    char token[2 * 16];

    su_md5_init(md5);

    if (sip->sip_payload) *pl = *sip->sip_payload;

    if (pl->pl_len)
      su_md5_update(md5, pl->pl_data, pl->pl_len);
    su_md5_update(md5, &pl->pl_len, sizeof(pl->pl_len));

    if (sip->sip_content_type)
      su_md5_striupdate(md5, sip->sip_content_type->c_type);

    su_md5_digest(md5, digest);
    token64_e(token, sizeof token, digest, sizeof digest);
    token[(sizeof token) - 1] = '\0';
    nu->nu_tag = su_strdup(nh->nh_home, token);
  }

  if (!nu->nu_requested || !nu->nu_tag)
    return 0;

  /* Check if SUBSCRIBE had matching suppression */
  for (sr = nh->nh_ds->ds_sr; sr; sr = sr->sr_next)
    if (sr->sr_usage == cr->cr_usage && sr->sr_method == sip_method_subscribe)
      break;

  if (sr) {
    sip_t const *sip = sr->sr_request.sip;

    sip_suppress_body_if_match_t *sbim;
    sip_suppress_notify_if_match_t *snim;
    
    if (cr->cr_usage->du_ready) {
      snim = sip_suppress_notify_if_match(sip);

      if (snim && !strcasecmp(snim->snim_tag, nu->nu_tag)) {
	if (nu->nu_requested > nu->nu_expires)
	  nu->nu_expires = nu->nu_requested;
	nu->nu_requested = 0;
	return nua_client_return(cr, 202, "NOTIFY Suppressed", msg);
      }
    }

    sbim = sip_suppress_body_if_match(sip);
    if (sbim && !strcasecmp(sbim->sbim_tag, nu->nu_tag))
      nu->nu_no_body = 1;
  }
#endif

  return 0;
}

static
int nua_notify_client_request(nua_client_request_t *cr,
			      msg_t *msg, sip_t *sip,
			      tagi_t const *tags)
{
  nua_dialog_usage_t *du = cr->cr_usage; 
  struct notifier_usage *nu = nua_dialog_usage_private(du);
  su_home_t *home = msg_home(msg);
  sip_time_t now = sip_now();
  sip_subscription_state_t *ss = sip->sip_subscription_state;
  char const *expires;

  if (du == NULL)		/* Subscription has been terminated */
    return nua_client_return(cr, SIP_481_NO_TRANSACTION, msg);

  assert(du && nu);

  if (du && nua_client_bind(cr, du) < 0)
    return -1;

  if (nu->nu_requested)
    nu->nu_expires = nu->nu_requested;
  nu->nu_requested = 0;

  if (nu->nu_expires <= now || du->du_shutdown) {
    nu->nu_substate = nua_substate_terminated;
    expires = "expires=0";
  }
  else {
    expires = su_sprintf(home, "expires=%lu", nu->nu_expires - now);
  }

  if (ss == NULL || nua_substate_make(ss->ss_substate) != nu->nu_substate) {
    if (nu->nu_substate == nua_substate_terminated)