irlmp.c

linux 内核源代码

 *    Incoming connection
 *
 */
void irlmp_connect_indication(struct lsap_cb *self, struct sk_buff *skb)
{
	int max_seg_size;
	int lap_header_size;
	int max_header_size;

	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LSAP_MAGIC, return;);
	IRDA_ASSERT(skb != NULL, return;);
	IRDA_ASSERT(self->lap != NULL, return;);

	IRDA_DEBUG(2, "%s(), slsap_sel=%02x, dlsap_sel=%02x\n",
		   __FUNCTION__, self->slsap_sel, self->dlsap_sel);

	/* Note : self->lap is set in irlmp_link_data_indication(),
	 * (case CONNECT_CMD:) because we have no way to set it here.
	 * Similarly, self->dlsap_sel is usually set in irlmp_find_lsap().
	 * Jean II */

	self->qos = *self->lap->qos;

	max_seg_size = self->lap->qos->data_size.value-LMP_HEADER;
	lap_header_size = IRLAP_GET_HEADER_SIZE(self->lap->irlap);
	max_header_size = LMP_HEADER + lap_header_size;

	/* Hide LMP_CONTROL_HEADER header from layer above */
	skb_pull(skb, LMP_CONTROL_HEADER);

	if (self->notify.connect_indication) {
		/* Don't forget to refcount it - see irlap_driver_rcv(). */
		skb_get(skb);
		self->notify.connect_indication(self->notify.instance, self,
						&self->qos, max_seg_size,
						max_header_size, skb);
	}
}

/*
 * Function irlmp_connect_response (handle, userdata)
 *
 *    Service user is accepting connection
 *
 */
int irlmp_connect_response(struct lsap_cb *self, struct sk_buff *userdata)
{
	IRDA_ASSERT(self != NULL, return -1;);
	IRDA_ASSERT(self->magic == LMP_LSAP_MAGIC, return -1;);
	IRDA_ASSERT(userdata != NULL, return -1;);

	/* We set the connected bit and move the lsap to the connected list
	 * in the state machine itself. Jean II */

	IRDA_DEBUG(2, "%s(), slsap_sel=%02x, dlsap_sel=%02x\n",
		   __FUNCTION__, self->slsap_sel, self->dlsap_sel);

	/* Make room for MUX control header (3 bytes) */
	IRDA_ASSERT(skb_headroom(userdata) >= LMP_CONTROL_HEADER, return -1;);
	skb_push(userdata, LMP_CONTROL_HEADER);

	irlmp_do_lsap_event(self, LM_CONNECT_RESPONSE, userdata);

	/* Drop reference count - see irlap_data_request(). */
	dev_kfree_skb(userdata);

	return 0;
}
EXPORT_SYMBOL(irlmp_connect_response);

/*
 * Function irlmp_connect_confirm (handle, skb)
 *
 *    LSAP connection confirmed peer device!
 */
void irlmp_connect_confirm(struct lsap_cb *self, struct sk_buff *skb)
{
	int max_header_size;
	int lap_header_size;
	int max_seg_size;

	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(skb != NULL, return;);
	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LSAP_MAGIC, return;);
	IRDA_ASSERT(self->lap != NULL, return;);

	self->qos = *self->lap->qos;

	max_seg_size    = self->lap->qos->data_size.value-LMP_HEADER;
	lap_header_size = IRLAP_GET_HEADER_SIZE(self->lap->irlap);
	max_header_size = LMP_HEADER + lap_header_size;

	IRDA_DEBUG(2, "%s(), max_header_size=%d\n",
		   __FUNCTION__, max_header_size);

	/* Hide LMP_CONTROL_HEADER header from layer above */
	skb_pull(skb, LMP_CONTROL_HEADER);

	if (self->notify.connect_confirm) {
		/* Don't forget to refcount it - see irlap_driver_rcv() */
		skb_get(skb);
		self->notify.connect_confirm(self->notify.instance, self,
					     &self->qos, max_seg_size,
					     max_header_size, skb);
	}
}

/*
 * Function irlmp_dup (orig, instance)
 *
 *    Duplicate LSAP, can be used by servers to confirm a connection on a
 *    new LSAP so it can keep listening on the old one.
 *
 */
struct lsap_cb *irlmp_dup(struct lsap_cb *orig, void *instance)
{
	struct lsap_cb *new;
	unsigned long flags;

	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	spin_lock_irqsave(&irlmp->unconnected_lsaps->hb_spinlock, flags);

	/* Only allowed to duplicate unconnected LSAP's, and only LSAPs
	 * that have received a connect indication. Jean II */
	if ((!hashbin_find(irlmp->unconnected_lsaps, (long) orig, NULL)) ||
	    (orig->lap == NULL)) {
		IRDA_DEBUG(0, "%s(), invalid LSAP (wrong state)\n",
			   __FUNCTION__);
		spin_unlock_irqrestore(&irlmp->unconnected_lsaps->hb_spinlock,
				       flags);
		return NULL;
	}

	/* Allocate a new instance */
	new = kmemdup(orig, sizeof(*new), GFP_ATOMIC);
	if (!new)  {
		IRDA_DEBUG(0, "%s(), unable to kmalloc\n", __FUNCTION__);
		spin_unlock_irqrestore(&irlmp->unconnected_lsaps->hb_spinlock,
				       flags);
		return NULL;
	}
	/* new->lap = orig->lap; => done in the memcpy() */
	/* new->slsap_sel = orig->slsap_sel; => done in the memcpy() */
	new->conn_skb = NULL;

	spin_unlock_irqrestore(&irlmp->unconnected_lsaps->hb_spinlock, flags);

	/* Not everything is the same */
	new->notify.instance = instance;

	init_timer(&new->watchdog_timer);

	hashbin_insert(irlmp->unconnected_lsaps, (irda_queue_t *) new,
		       (long) new, NULL);

#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
	/* Make sure that we invalidate the LSAP cache */
	new->lap->cache.valid = FALSE;
#endif /* CONFIG_IRDA_CACHE_LAST_LSAP */

	return new;
}

/*
 * Function irlmp_disconnect_request (handle, userdata)
 *
 *    The service user is requesting disconnection, this will not remove the
 *    LSAP, but only mark it as disconnected
 */
int irlmp_disconnect_request(struct lsap_cb *self, struct sk_buff *userdata)
{
	struct lsap_cb *lsap;

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

	/* Already disconnected ?
	 * There is a race condition between irlmp_disconnect_indication()
	 * and us that might mess up the hashbins below. This fixes it.
	 * Jean II */
	if (! test_and_clear_bit(0, &self->connected)) {
		IRDA_DEBUG(0, "%s(), already disconnected!\n", __FUNCTION__);
		dev_kfree_skb(userdata);
		return -1;
	}

	skb_push(userdata, LMP_CONTROL_HEADER);

	/*
	 *  Do the event before the other stuff since we must know
	 *  which lap layer that the frame should be transmitted on
	 */
	irlmp_do_lsap_event(self, LM_DISCONNECT_REQUEST, userdata);

	/* Drop reference count - see irlap_data_request(). */
	dev_kfree_skb(userdata);

	/*
	 *  Remove LSAP from list of connected LSAPs for the particular link
	 *  and insert it into the list of unconnected LSAPs
	 */
	IRDA_ASSERT(self->lap != NULL, return -1;);
	IRDA_ASSERT(self->lap->magic == LMP_LAP_MAGIC, return -1;);
	IRDA_ASSERT(self->lap->lsaps != NULL, return -1;);

	lsap = hashbin_remove(self->lap->lsaps, (long) self, NULL);
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
	self->lap->cache.valid = FALSE;
#endif

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

	hashbin_insert(irlmp->unconnected_lsaps, (irda_queue_t *) self,
		       (long) self, NULL);

	/* Reset some values */
	self->dlsap_sel = LSAP_ANY;
	self->lap = NULL;

	return 0;
}
EXPORT_SYMBOL(irlmp_disconnect_request);

/*
 * Function irlmp_disconnect_indication (reason, userdata)
 *
 *    LSAP is being closed!
 */
void irlmp_disconnect_indication(struct lsap_cb *self, LM_REASON reason,
				 struct sk_buff *skb)
{
	struct lsap_cb *lsap;

	IRDA_DEBUG(1, "%s(), reason=%s\n", __FUNCTION__, irlmp_reasons[reason]);
	IRDA_ASSERT(self != NULL, return;);
	IRDA_ASSERT(self->magic == LMP_LSAP_MAGIC, return;);

	IRDA_DEBUG(3, "%s(), slsap_sel=%02x, dlsap_sel=%02x\n",
		   __FUNCTION__, self->slsap_sel, self->dlsap_sel);

	/* Already disconnected ?
	 * There is a race condition between irlmp_disconnect_request()
	 * and us that might mess up the hashbins below. This fixes it.
	 * Jean II */
	if (! test_and_clear_bit(0, &self->connected)) {
		IRDA_DEBUG(0, "%s(), already disconnected!\n", __FUNCTION__);
		return;
	}

	/*
	 *  Remove association between this LSAP and the link it used
	 */
	IRDA_ASSERT(self->lap != NULL, return;);
	IRDA_ASSERT(self->lap->lsaps != NULL, return;);

	lsap = hashbin_remove(self->lap->lsaps, (long) self, NULL);
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
	self->lap->cache.valid = FALSE;
#endif

	IRDA_ASSERT(lsap != NULL, return;);
	IRDA_ASSERT(lsap == self, return;);
	hashbin_insert(irlmp->unconnected_lsaps, (irda_queue_t *) lsap,
		       (long) lsap, NULL);

	self->dlsap_sel = LSAP_ANY;
	self->lap = NULL;

	/*
	 *  Inform service user
	 */
	if (self->notify.disconnect_indication) {
		/* Don't forget to refcount it - see irlap_driver_rcv(). */
		if(skb)
			skb_get(skb);
		self->notify.disconnect_indication(self->notify.instance,
						   self, reason, skb);
	} else {
		IRDA_DEBUG(0, "%s(), no handler\n", __FUNCTION__);
	}
}

/*
 * Function irlmp_do_expiry (void)
 *
 *    Do a cleanup of the discovery log (remove old entries)
 *
 * Note : separate from irlmp_do_discovery() so that we can handle
 * passive discovery properly.
 */
void irlmp_do_expiry(void)
{
	struct lap_cb *lap;

	/*
	 * Expire discovery on all links which are *not* connected.
	 * On links which are connected, we can't do discovery
	 * anymore and can't refresh the log, so we freeze the
	 * discovery log to keep info about the device we are
	 * connected to.
	 * This info is mandatory if we want irlmp_connect_request()
	 * to work properly. - Jean II
	 */
	lap = (struct lap_cb *) hashbin_get_first(irlmp->links);
	while (lap != NULL) {
		IRDA_ASSERT(lap->magic == LMP_LAP_MAGIC, return;);

		if (lap->lap_state == LAP_STANDBY) {
			/* Expire discoveries discovered on this link */
			irlmp_expire_discoveries(irlmp->cachelog, lap->saddr,
						 FALSE);
		}
		lap = (struct lap_cb *) hashbin_get_next(irlmp->links);
	}
}

/*
 * Function irlmp_do_discovery (nslots)
 *
 *    Do some discovery on all links
 *
 * Note : log expiry is done above.
 */
void irlmp_do_discovery(int nslots)
{
	struct lap_cb *lap;
	__u16 *data_hintsp;

	/* Make sure the value is sane */
	if ((nslots != 1) && (nslots != 6) && (nslots != 8) && (nslots != 16)){
		IRDA_WARNING("%s: invalid value for number of slots!\n",
			     __FUNCTION__);
		nslots = sysctl_discovery_slots = 8;
	}

	/* Construct new discovery info to be used by IrLAP, */
	data_hintsp = (__u16 *) irlmp->discovery_cmd.data.hints;
	put_unaligned(irlmp->hints.word, data_hintsp);

	/*
	 *  Set character set for device name (we use ASCII), and
	 *  copy device name. Remember to make room for a \0 at the
	 *  end
	 */
	irlmp->discovery_cmd.data.charset = CS_ASCII;
	strncpy(irlmp->discovery_cmd.data.info, sysctl_devname,
		NICKNAME_MAX_LEN);
	irlmp->discovery_cmd.name_len = strlen(irlmp->discovery_cmd.data.info);
	irlmp->discovery_cmd.nslots = nslots;

	/*
	 * Try to send discovery packets on all links
	 */
	lap = (struct lap_cb *) hashbin_get_first(irlmp->links);
	while (lap != NULL) {
		IRDA_ASSERT(lap->magic == LMP_LAP_MAGIC, return;);

		if (lap->lap_state == LAP_STANDBY) {
			/* Try to discover */
			irlmp_do_lap_event(lap, LM_LAP_DISCOVERY_REQUEST,
					   NULL);
		}
		lap = (struct lap_cb *) hashbin_get_next(irlmp->links);
	}
}

/*
 * Function irlmp_discovery_request (nslots)
 *
 *    Do a discovery of devices in front of the computer
 *
 * If the caller has registered a client discovery callback, this
 * allow him to receive the full content of the discovery log through
 * this callback (as normally he will receive only new discoveries).
 */
void irlmp_discovery_request(int nslots)
{
	/* Return current cached discovery log (in full) */
	irlmp_discovery_confirm(irlmp->cachelog, DISCOVERY_LOG);

	/*
	 * Start a single discovery operation if discovery is not already
	 * running
	 */
	if (!sysctl_discovery) {
		/* Check if user wants to override the default */
		if (nslots == DISCOVERY_DEFAULT_SLOTS)
			nslots = sysctl_discovery_slots;

		irlmp_do_discovery(nslots);
		/* Note : we never do expiry here. Expiry will run on the
		 * discovery timer regardless of the state of sysctl_discovery
		 * Jean II */
	}
}
EXPORT_SYMBOL(irlmp_discovery_request);

/*
 * Function irlmp_get_discoveries (pn, mask, slots)
 *
 *    Return the current discovery log
 *
 * If discovery is not enabled, you should call this function again
 * after 1 or 2 seconds (i.e. after discovery has been done).
 */
struct irda_device_info *irlmp_get_discoveries(int *pn, __u16 mask, int nslots)
{
	/* If discovery is not enabled, it's likely that the discovery log
	 * will be empty. So, we trigger a single discovery, so that next
	 * time the user call us there might be some results in the log.
	 * Jean II
	 */
	if (!sysctl_discovery) {
		/* Check if user wants to override the default */
		if (nslots == DISCOVERY_DEFAULT_SLOTS)
			nslots = sysctl_discovery_slots;

		/* Start discovery - will complete sometime later */
		irlmp_do_discovery(nslots);
		/* Note : we never do expiry here. Expiry will run on the
		 * discovery timer regardless of the state of sysctl_discovery
		 * Jean II */
	}

	/* Return current cached discovery log */
	return(irlmp_copy_discoveries(irlmp->cachelog, pn, mask, TRUE));
}
EXPORT_SYMBOL(irlmp_get_discoveries);

/*
 * Function irlmp_notify_client (log)
 *
 *    Notify all about discovered devices
 *
 * Clients registered with IrLMP are :
 *	o IrComm
 *	o IrLAN
 *	o Any socket (in any state - ouch, that may be a lot !)
 * The client may have defined a callback to be notified in case of
 * partial/selective discovery based on the hints that it passed to IrLMP.
 */
static inline void
irlmp_notify_client(irlmp_client_t *client,
		    hashbin_t *log, DISCOVERY_MODE mode)
{
	discinfo_t *discoveries;	/* Copy of the discovery log */
	int	number;			/* Number of nodes in the log */
	int	i;

	IRDA_DEBUG(3, "%s()\n", __FUNCTION__);

	/* Check if client wants or not partial/selective log (optimisation) */
	if (!client->disco_callback)
		return;

	/*
	 * Locking notes :
	 * the old code was manipulating the log directly, which was
	 * very racy. Now, we use copy_discoveries, that protects
	 * itself while dumping the log for us.
	 * The overhead of the copy is compensated by the fact that
	 * we only pass new discoveries in normal mode and don't
	 * pass the same old entry every 3s to the caller as we used
	 * to do (virtual function calling is expensive).
	 * Jean II
	 */

	/*
	 * Now, check all discovered devices (if any), and notify client
	 * only about the services that the client is interested in
	 * We also notify only about the new devices unless the caller
	 * explicitly request a dump of the log. Jean II
	 */
	discoveries = irlmp_copy_discoveries(log, &number,
					     client->hint_mask.word,
					     (mode == DISCOVERY_LOG));
	/* Check if the we got some results */
	if (discoveries == NULL)
		return;	/* No nodes discovered */

	/* Pass all entries to the listener */
	for(i = 0; i < number; i++)
		client->disco_callback(&(discoveries[i]), mode, client->priv);

	/* Free up our buffer */
	kfree(discoveries);
}

/*
 * Function irlmp_discovery_confirm ( self, log)
 *
 *    Some device(s) answered to our discovery request! Check to see which
 *    device it is, and give indication to the client(s)
 *
 */
void irlmp_discovery_confirm(hashbin_t *log, DISCOVERY_MODE mode)
{
	irlmp_client_t *client;
	irlmp_client_t *client_next;