crypto.c

linux下基于加密芯片的加密设备

	if ((crp->crp_flags & CRYPTO_F_DONE) != 0)
		printk("crypto: crypto_done op already done, flags 0x%x",
				crp->crp_flags);
	crp->crp_flags |= CRYPTO_F_DONE;
	if (crp->crp_etype != 0)
		cryptostats.cs_errs++;
	/*
	 * CBIMM means unconditionally do the callback immediately;
	 * CBIFSYNC means do the callback immediately only if the
	 * operation was done synchronously.  Both are used to avoid
	 * doing extraneous context switches; the latter is mostly
	 * used with the software crypto driver.
	 */
	if ((crp->crp_flags & CRYPTO_F_CBIMM) ||
	    ((crp->crp_flags & CRYPTO_F_CBIFSYNC) &&
	     (CRYPTO_SESID2CAPS(crp->crp_sid) & CRYPTOCAP_F_SYNC))) {
		/*
		 * Do the callback directly.  This is ok when the
		 * callback routine does very little (e.g. the
		 * /dev/crypto callback method just does a wakeup).
		 */
		crp->crp_callback(crp);
	} else {
		int wasempty, r_flags;
		/*
		 * Normal case; queue the callback for the thread.
		 */
		CRYPTO_RETQ_LOCK();
		wasempty = list_empty(&crp_ret_q);
		list_add_tail(&crp->crp_list, &crp_ret_q);

		if (wasempty)
			wake_up_interruptible(&cryptoretproc_wait);	/*shared wait channel */
		CRYPTO_RETQ_UNLOCK();
	}
}

/*
 * Invoke the callback on behalf of the driver.
 */
void
crypto_kdone(struct cryptkop *krp)
{
	int wasempty, r_flags;

	if (krp->krp_status != 0)
		cryptostats.cs_kerrs++;
	CRYPTO_RETQ_LOCK();
	wasempty = list_empty(&crp_ret_kq);
	list_add_tail(&krp->krp_list, &crp_ret_kq);

	if (wasempty)
		wake_up_interruptible(&cryptoretproc_wait);	/* shared wait channel */
	CRYPTO_RETQ_UNLOCK();
}

int
crypto_getfeat(int *featp)
{
	int hid, kalg, feat = 0, d_flags;

	if (!crypto_userasymcrypto)
		goto out;	  

	CRYPTO_DRIVER_LOCK();
	for (hid = 0; hid < crypto_drivers_num; hid++) {
		if ((crypto_drivers[hid].cc_flags & CRYPTOCAP_F_SOFTWARE) &&
		    !crypto_devallowsoft) {
			continue;
		}
		if (crypto_drivers[hid].cc_kprocess == NULL)
			continue;
		for (kalg = 0; kalg < CRK_ALGORITHM_MAX; kalg++)
			if ((crypto_drivers[hid].cc_kalg[kalg] &
			    CRYPTO_ALG_FLAG_SUPPORTED) != 0)
				feat |=  1 << kalg;
	}
	CRYPTO_DRIVER_UNLOCK();
out:
	*featp = feat;
	return (0);
}

/*
 * Crypto thread, dispatches crypto requests.
 */
static int
crypto_proc(void *arg)
{
	struct cryptop *crp, *submit;
	struct cryptkop *krp, *krpp;
	struct cryptocap *cap;
	int result, hint, q_flags;

	daemonize();
	spin_lock_irq(&current->sigmask_lock);
	sigemptyset(&current->blocked);
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);
	sprintf(current->comm, "crypto");

	CRYPTO_Q_LOCK();
	for (;;) {
		/*
		 * Find the first element in the queue that can be
		 * processed and look-ahead to see if multiple ops
		 * are ready for the same driver.
		 */
		submit = NULL;
		hint = 0;
		list_for_each_entry(crp, &crp_q, crp_list) {
			u_int32_t hid = CRYPTO_SESID2HID(crp->crp_sid);
			cap = crypto_checkdriver(hid);
			if (cap == NULL || cap->cc_process == NULL) {
				/* Op needs to be migrated, process it. */
				if (submit == NULL)
					submit = crp;
				break;
			}
			if (!cap->cc_qblocked) {
				if (submit != NULL) {
					/*
					 * We stop on finding another op,
					 * regardless whether its for the same
					 * driver or not.  We could keep
					 * searching the queue but it might be
					 * better to just use a per-driver
					 * queue instead.
					 */
					if (CRYPTO_SESID2HID(submit->crp_sid) == hid)
						hint = CRYPTO_HINT_MORE;
					break;
				} else {
					submit = crp;
					if ((submit->crp_flags & CRYPTO_F_BATCH) == 0)
						break;
					/* keep scanning for more are q'd */
				}
			}
		}
		if (submit != NULL) {
			list_del(&submit->crp_list);
			result = crypto_invoke(submit, hint);
			if (result == ERESTART) {
				/*
				 * The driver ran out of resources, mark the
				 * driver ``blocked'' for cryptop's and put
				 * the request back in the queue.  It would
				 * best to put the request back where we got
				 * it but that's hard so for now we put it
				 * at the front.  This should be ok; putting
				 * it at the end does not work.
				 */
				/* XXX validate sid again? */
				crypto_drivers[CRYPTO_SESID2HID(submit->crp_sid)].cc_qblocked = 1;
				list_add(&submit->crp_list, &crp_q);
				cryptostats.cs_blocks++;
			}
		}

		/* As above, but for key ops */
		krp = NULL;
		list_for_each_entry(krpp, &crp_kq, krp_list) {
			cap = crypto_checkdriver(krpp->krp_hid);
			if (cap == NULL || cap->cc_kprocess == NULL) {
				/* Op needs to be migrated, process it. */
				krp = krpp;
				break;
			}
			if (!cap->cc_kqblocked) {
				krp = krpp;
				break;
			}
		}
		if (krp != NULL) {
			list_del(&krp->krp_list);
			result = crypto_kinvoke(krp, 0);
			if (result == ERESTART) {
				/*
				 * The driver ran out of resources, mark the
				 * driver ``blocked'' for cryptkop's and put
				 * the request back in the queue.  It would
				 * best to put the request back where we got
				 * it but that's hard so for now we put it
				 * at the front.  This should be ok; putting
				 * it at the end does not work.
				 */
				/* XXX validate sid again? */
				crypto_drivers[krp->krp_hid].cc_kqblocked = 1;
				list_add(&krp->krp_list, &crp_kq);
				cryptostats.cs_kblocks++;
			}
		}

		if (submit == NULL && krp == NULL) {
			/*
			 * Nothing more to be processed.  Sleep until we're
			 * woken because there are more ops to process.
			 * This happens either by submission or by a driver
			 * becoming unblocked and notifying us through
			 * crypto_unblock.  Note that when we wakeup we
			 * start processing each queue again from the
			 * front. It's not clear that it's important to
			 * preserve this ordering since ops may finish
			 * out of order if dispatched to different devices
			 * and some become blocked while others do not.
			 */
			dprintk("%s - sleeping\n", __FUNCTION__);
			CRYPTO_Q_UNLOCK();
			wait_event_interruptible(cryptoproc_wait,
					cryptoproc == (pid_t) -1 ||
					!list_empty(&crp_q) ||
					!list_empty(&crp_kq));
			if (signal_pending (current)) {
				spin_lock_irq(&current->sigmask_lock);
				flush_signals(current);
				spin_unlock_irq(&current->sigmask_lock);
			}
			CRYPTO_Q_LOCK();
			dprintk("%s - awake\n", __FUNCTION__);
			if (cryptoproc == (pid_t) -1)
				break;
			cryptostats.cs_intrs++;
		}
	}
	CRYPTO_Q_UNLOCK();
	complete_and_exit(&cryptoproc_exited, 0);
}

/*
 * Crypto returns thread, does callbacks for processed crypto requests.
 * Callbacks are done here, rather than in the crypto drivers, because
 * callbacks typically are expensive and would slow interrupt handling.
 */
static int
crypto_ret_proc(void *arg)
{
	struct cryptop *crpt;
	struct cryptkop *krpt;
	int r_flags;

	daemonize();
	spin_lock_irq(&current->sigmask_lock);
	sigemptyset(&current->blocked);
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);
	sprintf(current->comm, "crypto_ret");

	CRYPTO_RETQ_LOCK();
	for (;;) {
		/* Harvest return q's for completed ops */
		crpt = NULL;
		if (!list_empty(&crp_ret_q))
			crpt = list_entry(crp_ret_q.next, typeof(*crpt), crp_list);
		if (crpt != NULL)
			list_del(&crpt->crp_list);

		krpt = NULL;
		if (!list_empty(&crp_ret_kq))
			krpt = list_entry(crp_ret_kq.next, typeof(*krpt), krp_list);
		if (krpt != NULL)
			list_del(&krpt->krp_list);

		if (crpt != NULL || krpt != NULL) {
			CRYPTO_RETQ_UNLOCK();
			/*
			 * Run callbacks unlocked.
			 */
			if (crpt != NULL)
				crpt->crp_callback(crpt);
			if (krpt != NULL)
				krpt->krp_callback(krpt);
			CRYPTO_RETQ_LOCK();
		} else {
			/*
			 * Nothing more to be processed.  Sleep until we're
			 * woken because there are more returns to process.
			 */
			dprintk("%s - sleeping\n", __FUNCTION__);
			CRYPTO_RETQ_UNLOCK();
			wait_event_interruptible(cryptoretproc_wait,
					cryptoretproc == (pid_t) -1 ||
					!list_empty(&crp_ret_q) ||
					!list_empty(&crp_ret_kq));
			if (signal_pending (current)) {
				spin_lock_irq(&current->sigmask_lock);
				flush_signals(current);
				spin_unlock_irq(&current->sigmask_lock);
			}
			CRYPTO_RETQ_LOCK();
			dprintk("%s - awake\n", __FUNCTION__);
			if (cryptoretproc == (pid_t) -1)
				break;
			cryptostats.cs_rets++;
		}
	}
	CRYPTO_RETQ_UNLOCK();
	complete_and_exit(&cryptoretproc_exited, 0);
}


static int
crypto_init(void)
{
	int error;

	dprintk("%s(0x%x)\n", __FUNCTION__, (int) crypto_init);

	if (crypto_initted)
		return 0;
	crypto_initted = 1;

	spin_lock_init(&crypto_drivers_lock);
	spin_lock_init(&crypto_q_lock);
	spin_lock_init(&crypto_ret_q_lock);

	cryptop_zone = kmem_cache_create("cryptop", sizeof(struct cryptop),
				       0, SLAB_HWCACHE_ALIGN, NULL, NULL);
	cryptodesc_zone = kmem_cache_create("cryptodesc", sizeof(struct cryptodesc),
				       0, SLAB_HWCACHE_ALIGN, NULL, NULL);
	if (cryptodesc_zone == NULL || cryptop_zone == NULL) {
		printk("crypto: crypto_init cannot setup crypto zones\n");
		error = ENOMEM;
		goto bad;
	}

	crypto_drivers_num = CRYPTO_DRIVERS_INITIAL;
	crypto_drivers = kmalloc(crypto_drivers_num * sizeof(struct cryptocap),
			GFP_KERNEL);
	if (crypto_drivers == NULL) {
		printk("crypto: crypto_init cannot setup crypto drivers\n");
		error = ENOMEM;
		goto bad;
	}

	memset(crypto_drivers, 0, crypto_drivers_num * sizeof(struct cryptocap));

	init_completion(&cryptoproc_exited);
	init_completion(&cryptoretproc_exited);

	cryptoproc = kernel_thread(crypto_proc, NULL, CLONE_FS|CLONE_FILES);
	if (cryptoproc < 0) {
		error = cryptoproc;
		printk("crypto: crypto_init cannot start crypto thread; error %d",
			error);
		goto bad;
	}

	cryptoretproc = kernel_thread(crypto_ret_proc, NULL, CLONE_FS|CLONE_FILES);
	if (cryptoretproc < 0) {
		error = cryptoretproc;
		printk("crypto: crypto_init cannot start cryptoret thread; error %d",
				error);
		goto bad;
	}

	return 0;
bad:
	crypto_exit();
	return error;
}


static void
crypto_exit(void)
{
	pid_t p;
	int d_flags;

	dprintk("%s()\n", __FUNCTION__);
	/*
	 * Terminate any crypto threads.
	 */
	CRYPTO_DRIVER_LOCK();

	p = cryptoproc;
	cryptoproc = (pid_t) -1;
	kill_proc(p, SIGTERM, 1);
	wake_up_interruptible(&cryptoproc_wait);
	wait_for_completion(&cryptoproc_exited);

	p = cryptoretproc;
	cryptoretproc = (pid_t) -1;
	kill_proc(p, SIGTERM, 1);
	wake_up_interruptible(&cryptoretproc_wait);
	wait_for_completion(&cryptoretproc_exited);

	CRYPTO_DRIVER_UNLOCK();

	/* XXX flush queues??? */

	/* 
	 * Reclaim dynamically allocated resources.
	 */
	if (crypto_drivers != NULL)
		kfree(crypto_drivers);

	if (cryptodesc_zone != NULL)
		kmem_cache_destroy(cryptodesc_zone);
	if (cryptop_zone != NULL)
		kmem_cache_destroy(cryptop_zone);
}


EXPORT_SYMBOL(crypto_newsession);
EXPORT_SYMBOL(crypto_freesession);
EXPORT_SYMBOL(crypto_get_driverid);
EXPORT_SYMBOL(crypto_kregister);
EXPORT_SYMBOL(crypto_register);
EXPORT_SYMBOL(crypto_unregister);
EXPORT_SYMBOL(crypto_unregister_all);
EXPORT_SYMBOL(crypto_unblock);
EXPORT_SYMBOL(crypto_dispatch);
EXPORT_SYMBOL(crypto_kdispatch);
EXPORT_SYMBOL(crypto_freereq);
EXPORT_SYMBOL(crypto_getreq);
EXPORT_SYMBOL(crypto_done);
EXPORT_SYMBOL(crypto_kdone);
EXPORT_SYMBOL(crypto_getfeat);

module_init(crypto_init);
module_exit(crypto_exit);

MODULE_LICENSE("BSD");
MODULE_AUTHOR("[e-mail]");
MODULE_DESCRIPTION("OCF (OpenBSD Cryptographic Framework)");