irlap_event.c

linux 内核源代码

#ifdef CONFIG_IRDA_ULTRA
		/* Send any pending Ultra frames if any */
		if (!skb_queue_empty(&self->txq_ultra)) {
			/* We don't send the frame, just post an event.
			 * Also, previously this code was in timer.c...
			 * Jean II */
			ret = (*state[self->state])(self, SEND_UI_FRAME,
						    NULL, NULL);
		}
#endif /* CONFIG_IRDA_ULTRA */
		/* Check if we should try to connect.
		 * This code was previously in irlap_do_event() */
		if (self->connect_pending) {
			self->connect_pending = FALSE;

			/* This one *should* not pend in this state, except
			 * if a socket try to connect and immediately
			 * disconnect. - clear - Jean II */
			if (self->disconnect_pending)
				irlap_disconnect_indication(self, LAP_DISC_INDICATION);
			else
				ret = (*state[self->state])(self,
							    CONNECT_REQUEST,
							    NULL, NULL);
			self->disconnect_pending = FALSE;
		}
		/* Note : one way to test if this code works well (including
		 * media busy and small busy) is to create a user space
		 * application generating an Ultra packet every 3.05 sec (or
		 * 2.95 sec) and to see how it interact with discovery.
		 * It's fairly easy to check that no packet is lost, that the
		 * packets are postponed during discovery and that after
		 * discovery indication you have a 100ms "gap".
		 * As connection request and Ultra are now processed the same
		 * way, this avoid the tedious job of trying IrLAP connection
		 * in all those cases...
		 * Jean II */
		break;
#ifdef CONFIG_IRDA_ULTRA
	case SEND_UI_FRAME:
	{
		int i;
		/* Only allowed to repeat an operation twice */
		for (i=0; ((i<2) && (self->media_busy == FALSE)); i++) {
			skb = skb_dequeue(&self->txq_ultra);
			if (skb)
				irlap_send_ui_frame(self, skb, CBROADCAST,
						    CMD_FRAME);
			else
				break;
			/* irlap_send_ui_frame() won't increase skb reference
			 * count, so no dev_kfree_skb() - Jean II */
		}
		if (i == 2) {
			/* Force us to listen 500 ms again */
			irda_device_set_media_busy(self->netdev, TRUE);
		}
		break;
	}
	case RECV_UI_FRAME:
		/* Only accept broadcast frames in NDM mode */
		if (info->caddr != CBROADCAST) {
			IRDA_DEBUG(0, "%s(), not a broadcast frame!\n",
				   __FUNCTION__);
		} else
			irlap_unitdata_indication(self, skb);
		break;
#endif /* CONFIG_IRDA_ULTRA */
	case RECV_TEST_CMD:
		/* Remove test frame header */
		skb_pull(skb, sizeof(struct test_frame));

		/*
		 * Send response. This skb will not be sent out again, and
		 * will only be used to send out the same info as the cmd
		 */
		irlap_send_test_frame(self, CBROADCAST, info->daddr, skb);
		break;
	case RECV_TEST_RSP:
		IRDA_DEBUG(0, "%s() not implemented!\n", __FUNCTION__);
		break;
	default:
		IRDA_DEBUG(2, "%s(), Unknown event %s\n", __FUNCTION__,
			   irlap_event[event]);

		ret = -1;
		break;
	}
	return ret;
}

/*
 * Function irlap_state_query (event, skb, info)
 *
 *    QUERY state
 *
 */
static int irlap_state_query(struct irlap_cb *self, IRLAP_EVENT event,
			     struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	IRDA_ASSERT(self != NULL, return -1;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);

	switch (event) {
	case RECV_DISCOVERY_XID_RSP:
		IRDA_ASSERT(info != NULL, return -1;);
		IRDA_ASSERT(info->discovery != NULL, return -1;);

		IRDA_DEBUG(4, "%s(), daddr=%08x\n", __FUNCTION__,
			   info->discovery->data.daddr);

		if (!self->discovery_log) {
			IRDA_WARNING("%s: discovery log is gone! "
				     "maybe the discovery timeout has been set"
				     " too short?\n", __FUNCTION__);
			break;
		}
		hashbin_insert(self->discovery_log,
			       (irda_queue_t *) info->discovery,
			       info->discovery->data.daddr, NULL);

		/* Keep state */
		/* irlap_next_state(self, LAP_QUERY);  */

		break;
	case RECV_DISCOVERY_XID_CMD:
		/* Yes, it is possible to receive those frames in this mode.
		 * Note that most often the last discovery request won't
		 * occur here but in NDM state (see my comment there).
		 * What should we do ?
		 * Not much. We are currently performing our own discovery,
		 * therefore we can't answer those frames. We don't want
		 * to change state either. We just pass the info to
		 * IrLMP who will put it in the log (and post an event).
		 * Jean II
		 */

		IRDA_ASSERT(info != NULL, return -1;);

		IRDA_DEBUG(1, "%s(), Receiving discovery request (s = %d) while performing discovery :-(\n", __FUNCTION__, info->s);

		/* Last discovery request ? */
		if (info->s == 0xff)
			irlap_discovery_indication(self, info->discovery);
		break;
	case SLOT_TIMER_EXPIRED:
		/*
		 * Wait a little longer if we detect an incoming frame. This
		 * is not mentioned in the spec, but is a good thing to do,
		 * since we want to work even with devices that violate the
		 * timing requirements.
		 */
		if (irda_device_is_receiving(self->netdev) && !self->add_wait) {
			IRDA_DEBUG(2, "%s(), device is slow to answer, "
				   "waiting some more!\n", __FUNCTION__);
			irlap_start_slot_timer(self, msecs_to_jiffies(10));
			self->add_wait = TRUE;
			return ret;
		}
		self->add_wait = FALSE;

		if (self->s < self->S) {
			irlap_send_discovery_xid_frame(self, self->S,
						       self->s, TRUE,
						       self->discovery_cmd);
			self->s++;
			irlap_start_slot_timer(self, self->slot_timeout);

			/* Keep state */
			irlap_next_state(self, LAP_QUERY);
		} else {
			/* This is the final slot! */
			irlap_send_discovery_xid_frame(self, self->S, 0xff,
						       TRUE,
						       self->discovery_cmd);

			/* Always switch state before calling upper layers */
			irlap_next_state(self, LAP_NDM);

			/*
			 *  We are now finished with the discovery procedure,
			 *  so now we must return the results
			 */
			irlap_discovery_confirm(self, self->discovery_log);

			/* IrLMP should now have taken care of the log */
			self->discovery_log = NULL;
		}
		break;
	default:
		IRDA_DEBUG(2, "%s(), Unknown event %s\n", __FUNCTION__,
			   irlap_event[event]);

		ret = -1;
		break;
	}
	return ret;
}

/*
 * Function irlap_state_reply (self, event, skb, info)
 *
 *    REPLY, we have received a XID discovery frame from a device and we
 *    are waiting for the right time slot to send a response XID frame
 *
 */
static int irlap_state_reply(struct irlap_cb *self, IRLAP_EVENT event,
			     struct sk_buff *skb, struct irlap_info *info)
{
	discovery_t *discovery_rsp;
	int ret=0;

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return -1;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);

	switch (event) {
	case QUERY_TIMER_EXPIRED:
		IRDA_DEBUG(0, "%s(), QUERY_TIMER_EXPIRED <%ld>\n",
			   __FUNCTION__, jiffies);
		irlap_next_state(self, LAP_NDM);
		break;
	case RECV_DISCOVERY_XID_CMD:
		IRDA_ASSERT(info != NULL, return -1;);
		/* Last frame? */
		if (info->s == 0xff) {
			del_timer(&self->query_timer);

			/* info->log.condition = REMOTE; */

			/* Always switch state before calling upper layers */
			irlap_next_state(self, LAP_NDM);

			irlap_discovery_indication(self, info->discovery);
		} else {
			/* If it's our slot, send our reply */
			if ((info->s >= self->slot) && (!self->frame_sent)) {
				discovery_rsp = irlmp_get_discovery_response();
				discovery_rsp->data.daddr = info->daddr;

				irlap_send_discovery_xid_frame(self, info->S,
							       self->slot,
							       FALSE,
							       discovery_rsp);

				self->frame_sent = TRUE;
			}
			/* Readjust our timer to accomodate devices
			 * doing faster or slower discovery than us...
			 * Jean II */
			irlap_start_query_timer(self, info->S, info->s);

			/* Keep state */
			//irlap_next_state(self, LAP_REPLY);
		}
		break;
	default:
		IRDA_DEBUG(1, "%s(), Unknown event %d, %s\n", __FUNCTION__,
			   event, irlap_event[event]);

		ret = -1;
		break;
	}
	return ret;
}

/*
 * Function irlap_state_conn (event, skb, info)
 *
 *    CONN, we have received a SNRM command and is waiting for the upper
 *    layer to accept or refuse connection
 *
 */
static int irlap_state_conn(struct irlap_cb *self, IRLAP_EVENT event,
			    struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	IRDA_DEBUG(4, "%s(), event=%s\n", __FUNCTION__, irlap_event[ event]);

	IRDA_ASSERT(self != NULL, return -1;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);

	switch (event) {
	case CONNECT_RESPONSE:
		skb_pull(skb, sizeof(struct snrm_frame));

		IRDA_ASSERT(self->netdev != NULL, return -1;);

		irlap_qos_negotiate(self, skb);

		irlap_initiate_connection_state(self);

		/*
		 * Applying the parameters now will make sure we change speed
		 * *after* we have sent the next frame
		 */
		irlap_apply_connection_parameters(self, FALSE);

		/*
		 * Sending this frame will force a speed change after it has
		 * been sent (i.e. the frame will be sent at 9600).
		 */
		irlap_send_ua_response_frame(self, &self->qos_rx);

#if 0
		/*
		 * We are allowed to send two frames, but this may increase
		 * the connect latency, so lets not do it for now.
		 */
		/* This is full of good intentions, but doesn't work in
		 * practice.
		 * After sending the first UA response, we switch the
		 * dongle to the negotiated speed, which is usually
		 * different than 9600 kb/s.
		 * From there, there is two solutions :
		 * 1) The other end has received the first UA response :
		 * it will set up the connection, move to state LAP_NRM_P,
		 * and will ignore and drop the second UA response.
		 * Actually, it's even worse : the other side will almost
		 * immediately send a RR that will likely collide with the
		 * UA response (depending on negotiated turnaround).
		 * 2) The other end has not received the first UA response,
		 * will stay at 9600 and will never see the second UA response.
		 * Jean II */
		irlap_send_ua_response_frame(self, &self->qos_rx);
#endif

		/*
		 *  The WD-timer could be set to the duration of the P-timer
		 *  for this case, but it is recommended to use twice the
		 *  value (note 3 IrLAP p. 60).
		 */
		irlap_start_wd_timer(self, self->wd_timeout);
		irlap_next_state(self, LAP_NRM_S);

		break;
	case RECV_DISCOVERY_XID_CMD:
		IRDA_DEBUG(3, "%s(), event RECV_DISCOVER_XID_CMD!\n",
			   __FUNCTION__);
		irlap_next_state(self, LAP_NDM);

		break;
	case DISCONNECT_REQUEST:
		IRDA_DEBUG(0, "%s(), Disconnect request!\n", __FUNCTION__);
		irlap_send_dm_frame(self);
		irlap_next_state( self, LAP_NDM);
		irlap_disconnect_indication(self, LAP_DISC_INDICATION);
		break;
	default:
		IRDA_DEBUG(1, "%s(), Unknown event %d, %s\n", __FUNCTION__,
			   event, irlap_event[event]);

		ret = -1;
		break;
	}

	return ret;
}

/*
 * Function irlap_state_setup (event, skb, frame)
 *
 *    SETUP state, The local layer has transmitted a SNRM command frame to
 *    a remote peer layer and is awaiting a reply .
 *
 */
static int irlap_state_setup(struct irlap_cb *self, IRLAP_EVENT event,
			     struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return -1;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);

	switch (event) {
	case FINAL_TIMER_EXPIRED:
		if (self->retry_count < self->N3) {
/*
 *  Perform random backoff, Wait a random number of time units, minimum
 *  duration half the time taken to transmitt a SNRM frame, maximum duration
 *  1.5 times the time taken to transmit a SNRM frame. So this time should
 *  between 15 msecs and 45 msecs.
 */
			irlap_start_backoff_timer(self, msecs_to_jiffies(20 +
							(jiffies % 30)));
		} else {
			/* Always switch state before calling upper layers */
			irlap_next_state(self, LAP_NDM);

			irlap_disconnect_indication(self, LAP_FOUND_NONE);
		}
		break;
	case BACKOFF_TIMER_EXPIRED:
		irlap_send_snrm_frame(self, &self->qos_rx);
		irlap_start_final_timer(self, self->final_timeout);
		self->retry_count++;
		break;
	case RECV_SNRM_CMD:
		IRDA_DEBUG(4, "%s(), SNRM battle!\n", __FUNCTION__);

		IRDA_ASSERT(skb != NULL, return 0;);
		IRDA_ASSERT(info != NULL, return 0;);

		/*
		 *  The device with the largest device address wins the battle
		 *  (both have sent a SNRM command!)
		 */
		if (info &&(info->daddr > self->saddr)) {
			del_timer(&self->final_timer);
			irlap_initiate_connection_state(self);

			IRDA_ASSERT(self->netdev != NULL, return -1;);

			skb_pull(skb, sizeof(struct snrm_frame));

			irlap_qos_negotiate(self, skb);

			/* Send UA frame and then change link settings */
			irlap_apply_connection_parameters(self, FALSE);
			irlap_send_ua_response_frame(self, &self->qos_rx);

			irlap_next_state(self, LAP_NRM_S);
			irlap_connect_confirm(self, skb);

			/*
			 *  The WD-timer could be set to the duration of the
			 *  P-timer for this case, but it is recommended
			 *  to use twice the value (note 3 IrLAP p. 60).
			 */
			irlap_start_wd_timer(self, self->wd_timeout);
		} else {
			/* We just ignore the other device! */
			irlap_next_state(self, LAP_SETUP);
		}
		break;
	case RECV_UA_RSP:
		/* Stop F-timer */
		del_timer(&self->final_timer);

		/* Initiate connection state */
		irlap_initiate_connection_state(self);

		/* Negotiate connection parameters */
		IRDA_ASSERT(skb->len > 10, return -1;);

		skb_pull(skb, sizeof(struct ua_frame));

		IRDA_ASSERT(self->netdev != NULL, return -1;);

		irlap_qos_negotiate(self, skb);

		/* Set the new link setting *now* (before the rr frame) */
		irlap_apply_connection_parameters(self, TRUE);