irlmp.c

linux 内核源代码

/*********************************************************************
 *
 * Filename:      irlmp.c
 * Version:       1.0
 * Description:   IrDA Link Management Protocol (LMP) layer
 * Status:        Stable.
 * Author:        Dag Brattli <[e-mail]>
 * Created at:    Sun Aug 17 20:54:32 1997
 * Modified at:   Wed Jan  5 11:26:03 2000
 * Modified by:   Dag Brattli <[e-mail]>
 *
 *     Copyright (c) 1998-2000 Dag Brattli <[e-mail]>,
 *     All Rights Reserved.
 *     Copyright (c) 2000-2003 Jean Tourrilhes <[e-mail]>
 *
 *     This program is free software; you can redistribute it and/or
 *     modify it under the terms of the GNU General Public License as
 *     published by the Free Software Foundation; either version 2 of
 *     the License, or (at your option) any later version.
 *
 *     Neither Dag Brattli nor University of Tromsø admit liability nor
 *     provide warranty for any of this software. This material is
 *     provided "AS-IS" and at no charge.
 *
 ********************************************************************/

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/random.h>
#include <linux/seq_file.h>

#include <net/irda/irda.h>
#include <net/irda/timer.h>
#include <net/irda/qos.h>
#include <net/irda/irlap.h>
#include <net/irda/iriap.h>
#include <net/irda/irlmp.h>
#include <net/irda/irlmp_frame.h>

#include <asm/unaligned.h>

static __u8 irlmp_find_free_slsap(void);
static int irlmp_slsap_inuse(__u8 slsap_sel);

/* Master structure */
struct irlmp_cb *irlmp = NULL;

/* These can be altered by the sysctl interface */
int  sysctl_discovery         = 0;
int  sysctl_discovery_timeout = 3; /* 3 seconds by default */
int  sysctl_discovery_slots   = 6; /* 6 slots by default */
int  sysctl_lap_keepalive_time = LM_IDLE_TIMEOUT * 1000 / HZ;
char sysctl_devname[65];

const char *irlmp_reasons[] = {
	"ERROR, NOT USED",
	"LM_USER_REQUEST",
	"LM_LAP_DISCONNECT",
	"LM_CONNECT_FAILURE",
	"LM_LAP_RESET",
	"LM_INIT_DISCONNECT",
	"ERROR, NOT USED",
};

/*
 * Function irlmp_init (void)
 *
 *    Create (allocate) the main IrLMP structure
 *
 */
int __init irlmp_init(void)
{
	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);
	/* Initialize the irlmp structure. */
	irlmp = kzalloc( sizeof(struct irlmp_cb), GFP_KERNEL);
	if (irlmp == NULL)
		return -ENOMEM;

	irlmp->magic = LMP_MAGIC;

	irlmp->clients = hashbin_new(HB_LOCK);
	irlmp->services = hashbin_new(HB_LOCK);
	irlmp->links = hashbin_new(HB_LOCK);
	irlmp->unconnected_lsaps = hashbin_new(HB_LOCK);
	irlmp->cachelog = hashbin_new(HB_NOLOCK);

	if ((irlmp->clients == NULL) ||
	    (irlmp->services == NULL) ||
	    (irlmp->links == NULL) ||
	    (irlmp->unconnected_lsaps == NULL) ||
	    (irlmp->cachelog == NULL)) {
		return -ENOMEM;
	}

	spin_lock_init(&irlmp->cachelog->hb_spinlock);

	irlmp->last_lsap_sel = 0x0f; /* Reserved 0x00-0x0f */
	strcpy(sysctl_devname, "Linux");

	/* Do discovery every 3 seconds */
	init_timer(&irlmp->discovery_timer);
	irlmp_start_discovery_timer(irlmp, sysctl_discovery_timeout*HZ);

	return 0;
}

/*
 * Function irlmp_cleanup (void)
 *
 *    Remove IrLMP layer
 *
 */
void irlmp_cleanup(void)
{
	/* Check for main structure */
	IRDA_ASSERT(irlmp != NULL, return;);
	IRDA_ASSERT(irlmp->magic == LMP_MAGIC, return;);

	del_timer(&irlmp->discovery_timer);

	hashbin_delete(irlmp->links, (FREE_FUNC) kfree);
	hashbin_delete(irlmp->unconnected_lsaps, (FREE_FUNC) kfree);
	hashbin_delete(irlmp->clients, (FREE_FUNC) kfree);
	hashbin_delete(irlmp->services, (FREE_FUNC) kfree);
	hashbin_delete(irlmp->cachelog, (FREE_FUNC) kfree);

	/* De-allocate main structure */
	kfree(irlmp);
	irlmp = NULL;
}

/*
 * Function irlmp_open_lsap (slsap, notify)
 *
 *   Register with IrLMP and create a local LSAP,
 *   returns handle to LSAP.
 */
struct lsap_cb *irlmp_open_lsap(__u8 slsap_sel, notify_t *notify, __u8 pid)
{
	struct lsap_cb *self;

	IRDA_ASSERT(notify != NULL, return NULL;);
	IRDA_ASSERT(irlmp != NULL, return NULL;);
	IRDA_ASSERT(irlmp->magic == LMP_MAGIC, return NULL;);
	IRDA_ASSERT(notify->instance != NULL, return NULL;);

	/*  Does the client care which Source LSAP selector it gets?  */
	if (slsap_sel == LSAP_ANY) {
		slsap_sel = irlmp_find_free_slsap();
		if (!slsap_sel)
			return NULL;
	} else if (irlmp_slsap_inuse(slsap_sel))
		return NULL;

	/* Allocate new instance of a LSAP connection */
	self = kzalloc(sizeof(struct lsap_cb), GFP_ATOMIC);
	if (self == NULL) {
		IRDA_ERROR("%s: can't allocate memory\n", __FUNCTION__);
		return NULL;
	}

	self->magic = LMP_LSAP_MAGIC;
	self->slsap_sel = slsap_sel;

	/* Fix connectionless LSAP's */
	if (slsap_sel == LSAP_CONNLESS) {
#ifdef CONFIG_IRDA_ULTRA
		self->dlsap_sel = LSAP_CONNLESS;
		self->pid = pid;
#endif /* CONFIG_IRDA_ULTRA */
	} else
		self->dlsap_sel = LSAP_ANY;
	/* self->connected = FALSE; -> already NULL via memset() */

	init_timer(&self->watchdog_timer);

	self->notify = *notify;

	self->lsap_state = LSAP_DISCONNECTED;

	/* Insert into queue of unconnected LSAPs */
	hashbin_insert(irlmp->unconnected_lsaps, (irda_queue_t *) self,
		       (long) self, NULL);

	return self;
}
EXPORT_SYMBOL(irlmp_open_lsap);

/*
 * Function __irlmp_close_lsap (self)
 *
 *    Remove an instance of LSAP
 */
static void __irlmp_close_lsap(struct lsap_cb *self)
{
	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

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

	/*
	 *  Set some of the variables to preset values
	 */
	self->magic = 0;
	del_timer(&self->watchdog_timer); /* Important! */

	if (self->conn_skb)
		dev_kfree_skb(self->conn_skb);

	kfree(self);
}

/*
 * Function irlmp_close_lsap (self)
 *
 *    Close and remove LSAP
 *
 */
void irlmp_close_lsap(struct lsap_cb *self)
{
	struct lap_cb *lap;
	struct lsap_cb *lsap = NULL;

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

	/*
	 *  Find out if we should remove this LSAP from a link or from the
	 *  list of unconnected lsaps (not associated with a link)
	 */
	lap = self->lap;
	if (lap) {
		IRDA_ASSERT(lap->magic == LMP_LAP_MAGIC, return;);
		/* We might close a LSAP before it has completed the
		 * connection setup. In those case, higher layers won't
		 * send a proper disconnect request. Harmless, except
		 * that we will forget to close LAP... - Jean II */
		if(self->lsap_state != LSAP_DISCONNECTED) {
			self->lsap_state = LSAP_DISCONNECTED;
			irlmp_do_lap_event(self->lap,
					   LM_LAP_DISCONNECT_REQUEST, NULL);
		}
		/* Now, remove from the link */
		lsap = hashbin_remove(lap->lsaps, (long) self, NULL);
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
		lap->cache.valid = FALSE;
#endif
	}
	self->lap = NULL;
	/* Check if we found the LSAP! If not then try the unconnected lsaps */
	if (!lsap) {
		lsap = hashbin_remove(irlmp->unconnected_lsaps, (long) self,
				      NULL);
	}
	if (!lsap) {
		IRDA_DEBUG(0,
		     "%s(), Looks like somebody has removed me already!\n",
			   __FUNCTION__);
		return;
	}
	__irlmp_close_lsap(self);
}
EXPORT_SYMBOL(irlmp_close_lsap);

/*
 * Function irlmp_register_irlap (saddr, notify)
 *
 *    Register IrLAP layer with IrLMP. There is possible to have multiple
 *    instances of the IrLAP layer, each connected to different IrDA ports
 *
 */
void irlmp_register_link(struct irlap_cb *irlap, __u32 saddr, notify_t *notify)
{
	struct lap_cb *lap;

	IRDA_ASSERT(irlmp != NULL, return;);
	IRDA_ASSERT(irlmp->magic == LMP_MAGIC, return;);
	IRDA_ASSERT(notify != NULL, return;);

	/*
	 *  Allocate new instance of a LSAP connection
	 */
	lap = kzalloc(sizeof(struct lap_cb), GFP_KERNEL);
	if (lap == NULL) {
		IRDA_ERROR("%s: unable to kmalloc\n", __FUNCTION__);
		return;
	}

	lap->irlap = irlap;
	lap->magic = LMP_LAP_MAGIC;
	lap->saddr = saddr;
	lap->daddr = DEV_ADDR_ANY;
#ifdef CONFIG_IRDA_CACHE_LAST_LSAP
	lap->cache.valid = FALSE;
#endif
	lap->lsaps = hashbin_new(HB_LOCK);
	if (lap->lsaps == NULL) {
		IRDA_WARNING("%s(), unable to kmalloc lsaps\n", __FUNCTION__);
		kfree(lap);
		return;
	}

	lap->lap_state = LAP_STANDBY;

	init_timer(&lap->idle_timer);

	/*
	 *  Insert into queue of LMP links
	 */
	hashbin_insert(irlmp->links, (irda_queue_t *) lap, lap->saddr, NULL);

	/*
	 *  We set only this variable so IrLAP can tell us on which link the
	 *  different events happened on
	 */
	irda_notify_init(notify);
	notify->instance = lap;
}

/*
 * Function irlmp_unregister_irlap (saddr)
 *
 *    IrLAP layer has been removed!
 *
 */
void irlmp_unregister_link(__u32 saddr)
{
	struct lap_cb *link;

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

	/* We must remove ourselves from the hashbin *first*. This ensure
	 * that no more LSAPs will be open on this link and no discovery
	 * will be triggered anymore. Jean II */
	link = hashbin_remove(irlmp->links, saddr, NULL);
	if (link) {
		IRDA_ASSERT(link->magic == LMP_LAP_MAGIC, return;);

		/* Kill all the LSAPs on this link. Jean II */
		link->reason = LAP_DISC_INDICATION;
		link->daddr = DEV_ADDR_ANY;
		irlmp_do_lap_event(link, LM_LAP_DISCONNECT_INDICATION, NULL);

		/* Remove all discoveries discovered at this link */
		irlmp_expire_discoveries(irlmp->cachelog, link->saddr, TRUE);

		/* Final cleanup */
		del_timer(&link->idle_timer);
		link->magic = 0;
		hashbin_delete(link->lsaps, (FREE_FUNC) __irlmp_close_lsap);
		kfree(link);
	}
}

/*
 * Function irlmp_connect_request (handle, dlsap, userdata)
 *
 *    Connect with a peer LSAP
 *
 */
int irlmp_connect_request(struct lsap_cb *self, __u8 dlsap_sel,
			  __u32 saddr, __u32 daddr,
			  struct qos_info *qos, struct sk_buff *userdata)
{
	struct sk_buff *tx_skb = userdata;
	struct lap_cb *lap;
	struct lsap_cb *lsap;
	int ret;

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

	IRDA_DEBUG(2,
	      "%s(), slsap_sel=%02x, dlsap_sel=%02x, saddr=%08x, daddr=%08x\n",
	      __FUNCTION__, self->slsap_sel, dlsap_sel, saddr, daddr);

	if (test_bit(0, &self->connected)) {
		ret = -EISCONN;
		goto err;
	}

	/* Client must supply destination device address */
	if (!daddr) {
		ret = -EINVAL;
		goto err;
	}

	/* Any userdata? */
	if (tx_skb == NULL) {
		tx_skb = alloc_skb(LMP_MAX_HEADER, GFP_ATOMIC);
		if (!tx_skb)
			return -ENOMEM;

		skb_reserve(tx_skb, LMP_MAX_HEADER);
	}

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

	self->dlsap_sel = dlsap_sel;

	/*
	 * Find the link to where we should try to connect since there may
	 * be more than one IrDA port on this machine. If the client has
	 * passed us the saddr (and already knows which link to use), then
	 * we use that to find the link, if not then we have to look in the
	 * discovery log and check if any of the links has discovered a
	 * device with the given daddr
	 */
	if ((!saddr) || (saddr == DEV_ADDR_ANY)) {
		discovery_t *discovery;
		unsigned long flags;

		spin_lock_irqsave(&irlmp->cachelog->hb_spinlock, flags);
		if (daddr != DEV_ADDR_ANY)
			discovery = hashbin_find(irlmp->cachelog, daddr, NULL);
		else {
			IRDA_DEBUG(2, "%s(), no daddr\n", __FUNCTION__);
			discovery = (discovery_t *)
				hashbin_get_first(irlmp->cachelog);
		}

		if (discovery) {
			saddr = discovery->data.saddr;
			daddr = discovery->data.daddr;
		}
		spin_unlock_irqrestore(&irlmp->cachelog->hb_spinlock, flags);
	}
	lap = hashbin_lock_find(irlmp->links, saddr, NULL);
	if (lap == NULL) {
		IRDA_DEBUG(1, "%s(), Unable to find a usable link!\n", __FUNCTION__);
		ret = -EHOSTUNREACH;
		goto err;
	}

	/* Check if LAP is disconnected or already connected */
	if (lap->daddr == DEV_ADDR_ANY)
		lap->daddr = daddr;
	else if (lap->daddr != daddr) {
		/* Check if some LSAPs are active on this LAP */
		if (HASHBIN_GET_SIZE(lap->lsaps) == 0) {
			/* No active connection, but LAP hasn't been
			 * disconnected yet (waiting for timeout in LAP).
			 * Maybe we could give LAP a bit of help in this case.
			 */
			IRDA_DEBUG(0, "%s(), sorry, but I'm waiting for LAP to timeout!\n", __FUNCTION__);
			ret = -EAGAIN;
			goto err;
		}

		/* LAP is already connected to a different node, and LAP
		 * can only talk to one node at a time */
		IRDA_DEBUG(0, "%s(), sorry, but link is busy!\n", __FUNCTION__);
		ret = -EBUSY;
		goto err;
	}

	self->lap = lap;

	/*
	 *  Remove LSAP from list of unconnected LSAPs and insert it into the
	 *  list of connected LSAPs for the particular link
	 */
	lsap = hashbin_remove(irlmp->unconnected_lsaps, (long) self, NULL);

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

	hashbin_insert(self->lap->lsaps, (irda_queue_t *) self, (long) self,
		       NULL);

	set_bit(0, &self->connected);	/* TRUE */

	/*
	 *  User supplied qos specifications?
	 */
	if (qos)
		self->qos = *qos;

	irlmp_do_lsap_event(self, LM_CONNECT_REQUEST, tx_skb);

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

	return 0;

err:
	/* Cleanup */
	if(tx_skb)
		dev_kfree_skb(tx_skb);
	return ret;
}
EXPORT_SYMBOL(irlmp_connect_request);

/*
 * Function irlmp_connect_indication (self)
 *