text: /*	$OpenBSD: crypto.c,v 1.38 2002/06/11 11:14:29 beck Exp $	*/
  /*-
   * The author of this code is Angelos D. Keromytis (angelos@cis.upenn.edu)
   *
   * This code was written by Angelos D. Keromytis in Athens, Greece, in
   * February 2000. Network Security Technologies Inc. (NSTI) kindly
   * supported the development of this code.
   *
   * Copyright (c) 2000, 2001 Angelos D. Keromytis
   *
   * Permission to use, copy, and modify this software with or without fee
   * is hereby granted, provided that this entire notice is included in
   * all source code copies of any software which is or includes a copy or
   * modification of this software.
   *
   * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
   * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
   * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
   * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
   * PURPOSE.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: src/sys/opencrypto/crypto.c,v 1.17 2006/03/04 15:50:46 wkoszek Exp $");
  
  #define	CRYPTO_TIMING				/* enable timing support */
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/eventhandler.h>
  #include <sys/kernel.h>
  #include <sys/kthread.h>
  #include <sys/lock.h>
  #include <sys/module.h>
  #include <sys/mutex.h>
  #include <sys/malloc.h>
  #include <sys/proc.h>
  #include <sys/sysctl.h>
  
  #include <vm/uma.h>
  #include <opencrypto/cryptodev.h>
  #include <opencrypto/xform.h>			/* XXX for M_XDATA */
  
  /*
   * Crypto drivers register themselves by allocating a slot in the
   * crypto_drivers table with crypto_get_driverid() and then registering
   * each algorithm they support with crypto_register() and crypto_kregister().
   */
  static	struct mtx crypto_drivers_mtx;		/* lock on driver table */
  #define	CRYPTO_DRIVER_LOCK()	mtx_lock(&crypto_drivers_mtx)
  #define	CRYPTO_DRIVER_UNLOCK()	mtx_unlock(&crypto_drivers_mtx)
  static	struct cryptocap *crypto_drivers = NULL;
  static	int crypto_drivers_num = 0;
  
  /*
   * There are two queues for crypto requests; one for symmetric (e.g.
   * cipher) operations and one for asymmetric (e.g. MOD)operations.
   * A single mutex is used to lock access to both queues.  We could
   * have one per-queue but having one simplifies handling of block/unblock
   * operations.
   */
  static	TAILQ_HEAD(,cryptop) crp_q;		/* request queues */
  static	TAILQ_HEAD(,cryptkop) crp_kq;
  static	struct mtx crypto_q_mtx;
  #define	CRYPTO_Q_LOCK()		mtx_lock(&crypto_q_mtx)
  #define	CRYPTO_Q_UNLOCK()	mtx_unlock(&crypto_q_mtx)
  
  /*
   * There are two queues for processing completed crypto requests; one
   * for the symmetric and one for the asymmetric ops.  We only need one
   * but have two to avoid type futzing (cryptop vs. cryptkop).  A single
   * mutex is used to lock access to both queues.  Note that this lock
   * must be separate from the lock on request queues to insure driver
   * callbacks don't generate lock order reversals.
   */
  static	TAILQ_HEAD(,cryptop) crp_ret_q;		/* callback queues */
  static	TAILQ_HEAD(,cryptkop) crp_ret_kq;
  static	struct mtx crypto_ret_q_mtx;
  #define	CRYPTO_RETQ_LOCK()	mtx_lock(&crypto_ret_q_mtx)
  #define	CRYPTO_RETQ_UNLOCK()	mtx_unlock(&crypto_ret_q_mtx)
  
  static	uma_zone_t cryptop_zone;
  static	uma_zone_t cryptodesc_zone;
  
  int	crypto_userasymcrypto = 1;	/* userland may do asym crypto reqs */
  SYSCTL_INT(_kern, OID_AUTO, userasymcrypto, CTLFLAG_RW,
  	   &crypto_userasymcrypto, 0,
  	   "Enable/disable user-mode access to asymmetric crypto support");
  int	crypto_devallowsoft = 0;	/* only use hardware crypto for asym */
  SYSCTL_INT(_kern, OID_AUTO, cryptodevallowsoft, CTLFLAG_RW,
  	   &crypto_devallowsoft, 0,
  	   "Enable/disable use of software asym crypto support");
  
  MALLOC_DEFINE(M_CRYPTO_DATA, "crypto", "crypto session records");
  
  static	void crypto_proc(void);
  static	struct proc *cryptoproc;
  static	void crypto_ret_proc(void);
  static	struct proc *cryptoretproc;
  static	void crypto_destroy(void);
  static	int crypto_invoke(struct cryptop *crp, int hint);
  static	int crypto_kinvoke(struct cryptkop *krp, int hint);
  
  static	struct cryptostats cryptostats;
  SYSCTL_STRUCT(_kern, OID_AUTO, crypto_stats, CTLFLAG_RW, &cryptostats,
  	    cryptostats, "Crypto system statistics");
  
  #ifdef CRYPTO_TIMING
  static	int crypto_timing = 0;
  SYSCTL_INT(_debug, OID_AUTO, crypto_timing, CTLFLAG_RW,
  	   &crypto_timing, 0, "Enable/disable crypto timing support");
  #endif
  
  static int
  crypto_init(void)
  {
  	int error;
  
  	mtx_init(&crypto_drivers_mtx, "crypto", "crypto driver table",
  		MTX_DEF|MTX_QUIET);
  
  	TAILQ_INIT(&crp_q);
  	TAILQ_INIT(&crp_kq);
  	mtx_init(&crypto_q_mtx, "crypto", "crypto op queues", MTX_DEF);
  
  	TAILQ_INIT(&crp_ret_q);
  	TAILQ_INIT(&crp_ret_kq);
  	mtx_init(&crypto_ret_q_mtx, "crypto", "crypto return queues", MTX_DEF);
  
  	cryptop_zone = uma_zcreate("cryptop", sizeof (struct cryptop),
  				    0, 0, 0, 0,
  				    UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
  	cryptodesc_zone = uma_zcreate("cryptodesc", sizeof (struct cryptodesc),
  				    0, 0, 0, 0,
  				    UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
  	if (cryptodesc_zone == NULL || cryptop_zone == NULL) {
  		printf("crypto_init: cannot setup crypto zones\n");
  		error = ENOMEM;
  		goto bad;
  	}
  
  	crypto_drivers_num = CRYPTO_DRIVERS_INITIAL;
  	crypto_drivers = malloc(crypto_drivers_num *
  	    sizeof(struct cryptocap), M_CRYPTO_DATA, M_NOWAIT | M_ZERO);
  	if (crypto_drivers == NULL) {
  		printf("crypto_init: cannot setup crypto drivers\n");
  		error = ENOMEM;
  		goto bad;
  	}
  
  	error = kthread_create((void (*)(void *)) crypto_proc, NULL,
  		    &cryptoproc, 0, 0, "crypto");
  	if (error) {
  		printf("crypto_init: cannot start crypto thread; error %d",
  			error);
  		goto bad;
  	}
  
  	error = kthread_create((void (*)(void *)) crypto_ret_proc, NULL,
  		    &cryptoretproc, 0, 0, "crypto returns");
  	if (error) {
  		printf("crypto_init: cannot start cryptoret thread; error %d",
  			error);
  		goto bad;
  	}
  	return 0;
  bad:
  	crypto_destroy();
  	return error;
  }
  
  /*
   * Signal a crypto thread to terminate.  We use the driver
   * table lock to synchronize the sleep/wakeups so that we
   * are sure the threads have terminated before we release
   * the data structures they use.  See crypto_finis below
   * for the other half of this song-and-dance.
   */
  static void
  crypto_terminate(struct proc **pp, void *q)
  {
  	struct proc *p;
  
  	mtx_assert(&crypto_drivers_mtx, MA_OWNED);
  	p = *pp;
  	*pp = NULL;
  	if (p) {
  		wakeup_one(q);
  		PROC_LOCK(p);		/* NB: insure we don't miss wakeup */
  		CRYPTO_DRIVER_UNLOCK();	/* let crypto_finis progress */
  		msleep(p, &p->p_mtx, PWAIT, "crypto_destroy", 0);
  		PROC_UNLOCK(p);
  		CRYPTO_DRIVER_LOCK();
  	}
  }
  
  static void
  crypto_destroy(void)
  {
  	/*
  	 * Terminate any crypto threads.
  	 */
  	CRYPTO_DRIVER_LOCK();
  	crypto_terminate(&cryptoproc, &crp_q);
  	crypto_terminate(&cryptoretproc, &crp_ret_q);
  	CRYPTO_DRIVER_UNLOCK();
  
  	/* XXX flush queues??? */
  
  	/* 
  	 * Reclaim dynamically allocated resources.
  	 */
  	if (crypto_drivers != NULL)
  		free(crypto_drivers, M_CRYPTO_DATA);
  
  	if (cryptodesc_zone != NULL)
  		uma_zdestroy(cryptodesc_zone);
  	if (cryptop_zone != NULL)
  		uma_zdestroy(cryptop_zone);
  	mtx_destroy(&crypto_q_mtx);
  	mtx_destroy(&crypto_ret_q_mtx);
  	mtx_destroy(&crypto_drivers_mtx);
  }
  
  /*
   * Initialization code, both for static and dynamic loading.
   */
  static int
  crypto_modevent(module_t mod, int type, void *unused)
  {
  	int error = EINVAL;
  
  	switch (type) {
  	case MOD_LOAD:
  		error = crypto_init();
  		if (error == 0 && bootverbose)
  			printf("crypto: <crypto core>\n");
  		break;
  	case MOD_UNLOAD:
  		/*XXX disallow if active sessions */
  		error = 0;
  		crypto_destroy();
  		return 0;
  	}
  	return error;
  }
  
  static moduledata_t crypto_mod = {
  	"crypto",
  	crypto_modevent,
  	0
  };
  MODULE_VERSION(crypto, 1);
  DECLARE_MODULE(crypto, crypto_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
  MODULE_DEPEND(crypto, zlib, 1, 1, 1);
  
  /*
   * Create a new session.
   */
  int
  crypto_newsession(u_int64_t *sid, struct cryptoini *cri, int hard)
  {
  	struct cryptoini *cr;
  	u_int32_t hid, lid;
  	int err = EINVAL;
  
  	CRYPTO_DRIVER_LOCK();
  
  	if (crypto_drivers == NULL)
  		goto done;
  
  	/*
  	 * The algorithm we use here is pretty stupid; just use the
  	 * first driver that supports all the algorithms we need.
  	 *
  	 * XXX We need more smarts here (in real life too, but that's
  	 * XXX another story altogether).
  	 */
  
  	for (hid = 0; hid < crypto_drivers_num; hid++) {
  		struct cryptocap *cap = &crypto_drivers[hid];
  		/*
  		 * If it's not initialized or has remaining sessions
  		 * referencing it, skip.
  		 */
  		if (cap->cc_newsession == NULL ||
  		    (cap->cc_flags & CRYPTOCAP_F_CLEANUP))
  			continue;
  
  		/* Hardware required -- ignore software drivers. */
  		if (hard > 0 && (cap->cc_flags & CRYPTOCAP_F_SOFTWARE))
  			continue;
  		/* Software required -- ignore hardware drivers. */
  		if (hard < 0 && (cap->cc_flags & CRYPTOCAP_F_SOFTWARE) == 0)
  			continue;
  
  		/* See if all the algorithms are supported. */
  		for (cr = cri; cr; cr = cr->cri_next)
  			if (cap->cc_alg[cr->cri_alg] == 0)
  				break;
  
  		if (cr == NULL) {
  			/* Ok, all algorithms are supported. */
  
  			/*
  			 * Can't do everything in one session.
  			 *
  			 * XXX Fix this. We need to inject a "virtual" session layer right
  			 * XXX about here.
  			 */
  
  			/* Call the driver initialization routine. */
  			lid = hid;		/* Pass the driver ID. */
  			err = (*cap->cc_newsession)(cap->cc_arg, &lid, cri);
  			if (err == 0) {
  				/* XXX assert (hid &~ 0xffffff) == 0 */
  				/* XXX assert (cap->cc_flags &~ 0xff) == 0 */
  				(*sid) = ((cap->cc_flags & 0xff) << 24) | hid;
  				(*sid) <<= 32;
  				(*sid) |= (lid & 0xffffffff);
  				cap->cc_sessions++;
  			}
  			break;
  		}
  	}
  done:
  	CRYPTO_DRIVER_UNLOCK();
  	return err;
  }
  
  /*
   * Delete an existing session (or a reserved session on an unregistered
   * driver).
   */
  int
  crypto_freesession(u_int64_t sid)
  {
  	u_int32_t hid;
  	int err;
  
  	CRYPTO_DRIVER_LOCK();
  
  	if (crypto_drivers == NULL) {
  		err = EINVAL;
  		goto done;
  	}
  
  	/* Determine two IDs. */
  	hid = CRYPTO_SESID2HID(sid);
  
  	if (hid >= crypto_drivers_num) {
  		err = ENOENT;
  		goto done;
  	}
  
  	if (crypto_drivers[hid].cc_sessions)
  		crypto_drivers[hid].cc_sessions--;
  
  	/* Call the driver cleanup routine, if available. */
  	if (crypto_drivers[hid].cc_freesession)
  		err = crypto_drivers[hid].cc_freesession(
  				crypto_drivers[hid].cc_arg, sid);
  	else
  		err = 0;
  
  	/*
  	 * If this was the last session of a driver marked as invalid,
  	 * make the entry available for reuse.
  	 */
  	if ((crypto_drivers[hid].cc_flags & CRYPTOCAP_F_CLEANUP) &&
  	    crypto_drivers[hid].cc_sessions == 0)
  		bzero(&crypto_drivers[hid], sizeof(struct cryptocap));
  
  done:
  	CRYPTO_DRIVER_UNLOCK();
  	return err;
  }
  
  /*
   * Return an unused driver id.  Used by drivers prior to registering
   * support for the algorithms they handle.
   */
  int32_t
  crypto_get_driverid(u_int32_t flags)
  {
  	struct cryptocap *newdrv;
  	int i;
  
  	CRYPTO_DRIVER_LOCK();
  
  	for (i = 0; i < crypto_drivers_num; i++)
  		if (crypto_drivers[i].cc_process == NULL &&
  		    (crypto_drivers[i].cc_flags & CRYPTOCAP_F_CLEANUP) == 0 &&
  		    crypto_drivers[i].cc_sessions == 0)
  			break;
  
  	/* Out of entries, allocate some more. */
  	if (i == crypto_drivers_num) {
  		/* Be careful about wrap-around. */
  		if (2 * crypto_drivers_num <= crypto_drivers_num) {
  			CRYPTO_DRIVER_UNLOCK();
  			printf("crypto: driver count wraparound!\n");
  			return -1;
  		}
  
  		newdrv = malloc(2 * crypto_drivers_num *
  		    sizeof(struct cryptocap), M_CRYPTO_DATA, M_NOWAIT|M_ZERO);
  		if (newdrv == NULL) {
  			CRYPTO_DRIVER_UNLOCK();
  			printf("crypto: no space to expand driver table!\n");
  			return -1;
  		}
  
  		bcopy(crypto_drivers, newdrv,
  		    crypto_drivers_num * sizeof(struct cryptocap));
  
  		crypto_drivers_num *= 2;
  
  		free(crypto_drivers, M_CRYPTO_DATA);
  		crypto_drivers = newdrv;
  	}
  
  	/* NB: state is zero'd on free */
  	crypto_drivers[i].cc_sessions = 1;	/* Mark */
  	crypto_drivers[i].cc_flags = flags;
  	if (bootverbose)
  		printf("crypto: assign driver %u, flags %u\n", i, flags);
  
  	CRYPTO_DRIVER_UNLOCK();
  
  	return i;
  }
  
  static struct cryptocap *
  crypto_checkdriver(u_int32_t hid)
  {
  	if (crypto_drivers == NULL)
  		return NULL;
  	return (hid >= crypto_drivers_num ? NULL : &crypto_drivers[hid]);
  }
  
  /*
   * Register support for a key-related algorithm.  This routine
   * is called once for each algorithm supported a driver.
   */
  int
  crypto_kregister(u_int32_t driverid, int kalg, u_int32_t flags,
      int (*kprocess)(void*, struct cryptkop *, int),
      void *karg)
  {
  	struct cryptocap *cap;
  	int err;
  
  	CRYPTO_DRIVER_LOCK();
  
  	cap = crypto_checkdriver(driverid);
  	if (cap != NULL &&
  	    (CRK_ALGORITM_MIN <= kalg && kalg <= CRK_ALGORITHM_MAX)) {
  		/*
  		 * XXX Do some performance testing to determine placing.
  		 * XXX We probably need an auxiliary data structure that
  		 * XXX describes relative performances.
  		 */
  
  		cap->cc_kalg[kalg] = flags | CRYPTO_ALG_FLAG_SUPPORTED;
  		if (bootverbose)
  			printf("crypto: driver %u registers key alg %u flags %u\n"
  				, driverid
  				, kalg
  				, flags
  			);
  
  		if (cap->cc_kprocess == NULL) {
  			cap->cc_karg = karg;
  			cap->cc_kprocess = kprocess;
  		}
  		err = 0;
  	} else
  		err = EINVAL;
  
  	CRYPTO_DRIVER_UNLOCK();
  	return err;
  }
  
  /*
   * Register support for a non-key-related algorithm.  This routine
   * is called once for each such algorithm supported by a driver.
   */
  int
  crypto_register(u_int32_t driverid, int alg, u_int16_t maxoplen,
      u_int32_t flags,
      int (*newses)(void*, u_int32_t*, struct cryptoini*),
      int (*freeses)(void*, u_int64_t),
      int (*process)(void*, struct cryptop *, int),
      void *arg)
  {
  	struct cryptocap *cap;
  	int err;
  
  	CRYPTO_DRIVER_LOCK();
  
  	cap = crypto_checkdriver(driverid);
  	/* NB: algorithms are in the range [1..max] */
  	if (cap != NULL &&
  	    (CRYPTO_ALGORITHM_MIN <= alg && alg <= CRYPTO_ALGORITHM_MAX)) {
  		/*
  		 * XXX Do some performance testing to determine placing.
  		 * XXX We probably need an auxiliary data structure that
  		 * XXX describes relative performances.
  		 */
  
  		cap->cc_alg[alg] = flags | CRYPTO_ALG_FLAG_SUPPORTED;
  		cap->cc_max_op_len[alg] = maxoplen;
  		if (bootverbose)
  			printf("crypto: driver %u registers alg %u flags %u maxoplen %u\n"
  				, driverid
  				, alg
  				, flags
  				, maxoplen
  			);
  
  		if (cap->cc_process == NULL) {
  			cap->cc_arg = arg;
  			cap->cc_newsession = newses;
  			cap->cc_process = process;
  			cap->cc_freesession = freeses;
  			cap->cc_sessions = 0;		/* Unmark */
  		}
  		err = 0;
  	} else
  		err = EINVAL;
  
  	CRYPTO_DRIVER_UNLOCK();
  	return err;
  }
  
  /*
   * Unregister a crypto driver. If there are pending sessions using it,
   * leave enough information around so that subsequent calls using those
   * sessions will correctly detect the driver has been unregistered and
   * reroute requests.
   */
  int
  crypto_unregister(u_int32_t driverid, int alg)
  {
  	int i, err;
  	u_int32_t ses;
  	struct cryptocap *cap;
  
  	CRYPTO_DRIVER_LOCK();
  
  	cap = crypto_checkdriver(driverid);
  	if (cap != NULL &&
  	    (CRYPTO_ALGORITHM_MIN <= alg && alg <= CRYPTO_ALGORITHM_MAX) &&
  	    cap->cc_alg[alg] != 0) {
  		cap->cc_alg[alg] = 0;
  		cap->cc_max_op_len[alg] = 0;
  
  		/* Was this the last algorithm ? */
  		for (i = 1; i <= CRYPTO_ALGORITHM_MAX; i++)
  			if (cap->cc_alg[i] != 0)
  				break;
  
  		if (i == CRYPTO_ALGORITHM_MAX + 1) {
  			ses = cap->cc_sessions;
  			bzero(cap, sizeof(struct cryptocap));
  			if (ses != 0) {
  				/*
  				 * If there are pending sessions, just mark as invalid.
  				 */
  				cap->cc_flags |= CRYPTOCAP_F_CLEANUP;
  				cap->cc_sessions = ses;
  			}
  		}
  		err = 0;
  	} else
  		err = EINVAL;
  
  	CRYPTO_DRIVER_UNLOCK();
  	return err;
  }
  
  /*
   * Unregister all algorithms associated with a crypto driver.
   * If there are pending sessions using it, leave enough information
   * around so that subsequent calls using those sessions will
   * correctly detect the driver has been unregistered and reroute
   * requests.
   */
  int
  crypto_unregister_all(u_int32_t driverid)
  {
  	int i, err;
  	u_int32_t ses;
  	struct cryptocap *cap;
  
  	CRYPTO_DRIVER_LOCK();
  
  	cap = crypto_checkdriver(driverid);
  	if (cap != NULL) {
  		for (i = CRYPTO_ALGORITHM_MIN; i <= CRYPTO_ALGORITHM_MAX; i++) {
  			cap->cc_alg[i] = 0;
  			cap->cc_max_op_len[i] = 0;
  		}
  		ses = cap->cc_sessions;
  		bzero(cap, sizeof(struct cryptocap));
  		if (ses != 0) {
  			/*
  			 * If there are pending sessions, just mark as invalid.
  			 */
  			cap->cc_flags |= CRYPTOCAP_F_CLEANUP;
  			cap->cc_sessions = ses;
  		}
  		err = 0;
  	} else
  		err = EINVAL;
  
  	CRYPTO_DRIVER_UNLOCK();
  	return err;
  }
  
  /*
   * Clear blockage on a driver.  The what parameter indicates whether
   * the driver is now ready for cryptop's and/or cryptokop's.
   */
  int
  crypto_unblock(u_int32_t driverid, int what)
  {
  	struct cryptocap *cap;
  	int needwakeup, err;
  
  	CRYPTO_Q_LOCK();
  	cap = crypto_checkdriver(driverid);
  	if (cap != NULL) {
  		needwakeup = 0;
  		if (what & CRYPTO_SYMQ) {
  			needwakeup |= cap->cc_qblocked;
  			cap->cc_qblocked = 0;
  		}
  		if (what & CRYPTO_ASYMQ) {
  			needwakeup |= cap->cc_kqblocked;
  			cap->cc_kqblocked = 0;
  		}
  		if (needwakeup)
  			wakeup_one(&crp_q);
  		err = 0;
  	} else
  		err = EINVAL;
  	CRYPTO_Q_UNLOCK();
  
  	return err;
  }
  
  /*
   * Add a crypto request to a queue, to be processed by the kernel thread.
   */
  int
  crypto_dispatch(struct cryptop *crp)
  {
  	u_int32_t hid = CRYPTO_SESID2HID(crp->crp_sid);
  	int result;
  
  	cryptostats.cs_ops++;
  
  #ifdef CRYPTO_TIMING
  	if (crypto_timing)
  		binuptime(&crp->crp_tstamp);
  #endif
  
  	CRYPTO_Q_LOCK();
  	if ((crp->crp_flags & CRYPTO_F_BATCH) == 0) {
  		struct cryptocap *cap;
  		/*
  		 * Caller marked the request to be processed
  		 * immediately; dispatch it directly to the
  		 * driver unless the driver is currently blocked.
  		 */
  		cap = crypto_checkdriver(hid);
  		if (cap && !cap->cc_qblocked) {
  			result = crypto_invoke(crp, 0);
  			if (result == ERESTART) {
  				/*
  				 * The driver ran out of resources, mark the
  				 * driver ``blocked'' for cryptop's and put
  				 * the request on the queue.
  				 *
  				 * XXX ops are placed at the tail so their
  				 * order is preserved but this can place them
  				 * behind batch'd ops.
  				 */
  				crypto_drivers[hid].cc_qblocked = 1;
  				TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
  				cryptostats.cs_blocks++;
  				result = 0;
  			}
  		} else {
  			/*
  			 * The driver is blocked, just queue the op until
  			 * it unblocks and the kernel thread gets kicked.
  			 */
  			TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
  			result = 0;
  		}
  	} else {
  		int wasempty;
  		/*
  		 * Caller marked the request as ``ok to delay'';
  		 * queue it for the dispatch thread.  This is desirable
  		 * when the operation is low priority and/or suitable
  		 * for batching.
  		 */
  		wasempty = TAILQ_EMPTY(&crp_q);
  		TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
  		if (wasempty)
  			wakeup_one(&crp_q);
  		result = 0;
  	}
  	CRYPTO_Q_UNLOCK();
  
  	return result;
  }
  
  /*
   * Add an asymetric crypto request to a queue,
   * to be processed by the kernel thread.
   */
  int
  crypto_kdispatch(struct cryptkop *krp)
  {
  	struct cryptocap *cap;
  	int result;
  
  	cryptostats.cs_kops++;
  
  	CRYPTO_Q_LOCK();
  	cap = crypto_checkdriver(krp->krp_hid);
  	if (cap && !cap->cc_kqblocked) {
  		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.
  			 */
  			crypto_drivers[krp->krp_hid].cc_kqblocked = 1;
  			TAILQ_INSERT_TAIL(&crp_kq, krp, krp_next);
  			cryptostats.cs_kblocks++;
  		}
  	} else {
  		/*
  		 * The driver is blocked, just queue the op until
  		 * it unblocks and the kernel thread gets kicked.
  		 */
  		TAILQ_INSERT_TAIL(&crp_kq, krp, krp_next);
  		result = 0;
  	}
  	CRYPTO_Q_UNLOCK();
  
  	return result;
  }
  
  /*
   * Dispatch an assymetric crypto request to the appropriate crypto devices.
   */
  static int
  crypto_kinvoke(struct cryptkop *krp, int hint)
  {
  	u_int32_t hid;
  	int error;
  
  	mtx_assert(&crypto_q_mtx, MA_OWNED);
  
  	/* Sanity checks. */
  	if (krp == NULL)
  		return EINVAL;
  	if (krp->krp_callback == NULL) {
  		free(krp, M_XDATA);		/* XXX allocated in cryptodev */
  		return EINVAL;
  	}
  
  	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;
  		if ((crypto_drivers[hid].cc_kalg[krp->krp_op] &
  		    CRYPTO_ALG_FLAG_SUPPORTED) == 0)
  			continue;
  		break;
  	}
  	if (hid < crypto_drivers_num) {
  		krp->krp_hid = hid;
  		error = crypto_drivers[hid].cc_kprocess(
  				crypto_drivers[hid].cc_karg, krp, hint);
  	} else
  		error = ENODEV;
  
  	if (error) {
  		krp->krp_status = error;
  		crypto_kdone(krp);
  	}
  	return 0;
  }
  
  #ifdef CRYPTO_TIMING
  static void
  crypto_tstat(struct cryptotstat *ts, struct bintime *bt)
  {
  	struct bintime now, delta;
  	struct timespec t;
  	uint64_t u;
  
  	binuptime(&now);
  	u = now.frac;
  	delta.frac = now.frac - bt->frac;
  	delta.sec = now.sec - bt->sec;
  	if (u < delta.frac)
  		delta.sec--;
  	bintime2timespec(&delta, &t);
  	timespecadd(&ts->acc, &t);
  	if (timespeccmp(&t, &ts->min, <))
  		ts->min = t;
  	if (timespeccmp(&t, &ts->max, >))
  		ts->max = t;
  	ts->count++;
  
  	*bt = now;
  }
  #endif
  
  /*
   * Dispatch a crypto request to the appropriate crypto devices.
   */
  static int
  crypto_invoke(struct cryptop *crp, int hint)
  {
  	u_int32_t hid;
  	int (*process)(void*, struct cryptop *, int);
  
  #ifdef CRYPTO_TIMING
  	if (crypto_timing)
  		crypto_tstat(&cryptostats.cs_invoke, &crp->crp_tstamp);
  #endif
  	/* Sanity checks. */
  	if (crp == NULL)
  		return EINVAL;
  	if (crp->crp_callback == NULL) {
  		crypto_freereq(crp);
  		return EINVAL;
  	}
  	if (crp->crp_desc == NULL) {
  		crp->crp_etype = EINVAL;
  		crypto_done(crp);
  		return 0;
  	}
  
  	hid = CRYPTO_SESID2HID(crp->crp_sid);
  	if (hid < crypto_drivers_num) {
  		if (crypto_drivers[hid].cc_flags & CRYPTOCAP_F_CLEANUP)
  			crypto_freesession(crp->crp_sid);
  		process = crypto_drivers[hid].cc_process;
  	} else {
  		process = NULL;
  	}
  
  	if (process == NULL) {
  		struct cryptodesc *crd;
  		u_int64_t nid;
  
  		/*
  		 * Driver has unregistered; migrate the session and return
  		 * an error to the caller so they'll resubmit the op.
  		 */
  		for (crd = crp->crp_desc; crd->crd_next; crd = crd->crd_next)
  			crd->CRD_INI.cri_next = &(crd->crd_next->CRD_INI);
  
  		if (crypto_newsession(&nid, &(crp->crp_desc->CRD_INI), 0) == 0)
  			crp->crp_sid = nid;
  
  		crp->crp_etype = EAGAIN;
  		crypto_done(crp);
  		return 0;
  	} else {
  		/*
  		 * Invoke the driver to process the request.
  		 */
  		return (*process)(crypto_drivers[hid].cc_arg, crp, hint);
  	}
  }
  
  /*
   * Release a set of crypto descriptors.
   */
  void
  crypto_freereq(struct cryptop *crp)
  {
  	struct cryptodesc *crd;
  
  	if (crp == NULL)
  		return;
  
  	while ((crd = crp->crp_desc) != NULL) {
  		crp->crp_desc = crd->crd_next;
  		uma_zfree(cryptodesc_zone, crd);
  	}
  
  	uma_zfree(cryptop_zone, crp);
  }
  
  /*
   * Acquire a set of crypto descriptors.
   */
  struct cryptop *
  crypto_getreq(int num)
  {
  	struct cryptodesc *crd;
  	struct cryptop *crp;
  
  	crp = uma_zalloc(cryptop_zone, M_NOWAIT|M_ZERO);
  	if (crp != NULL) {
  		while (num--) {
  			crd = uma_zalloc(cryptodesc_zone, M_NOWAIT|M_ZERO);
  			if (crd == NULL) {
  				crypto_freereq(crp);
  				return NULL;
  			}
  
  			crd->crd_next = crp->crp_desc;
  			crp->crp_desc = crd;
  		}
  	}
  	return crp;
  }
  
  /*
   * Invoke the callback on behalf of the driver.
   */
  void
  crypto_done(struct cryptop *crp)
  {
  	KASSERT((crp->crp_flags & CRYPTO_F_DONE) == 0,
  		("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++;
  #ifdef CRYPTO_TIMING
  	if (crypto_timing)
  		crypto_tstat(&cryptostats.cs_done, &crp->crp_tstamp);
  #endif
  	/*
  	 * 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).
  		 */
  #ifdef CRYPTO_TIMING
  		if (crypto_timing) {
  			/*
  			 * NB: We must copy the timestamp before
  			 * doing the callback as the cryptop is
  			 * likely to be reclaimed.
  			 */
  			struct bintime t = crp->crp_tstamp;
  			crypto_tstat(&cryptostats.cs_cb, &t);
  			crp->crp_callback(crp);
  			crypto_tstat(&cryptostats.cs_finis, &t);
  		} else
  #endif
  			crp->crp_callback(crp);
  	} else {
  		int wasempty;
  		/*
  		 * Normal case; queue the callback for the thread.
  		 */
  		CRYPTO_RETQ_LOCK();
  		wasempty = TAILQ_EMPTY(&crp_ret_q);
  		TAILQ_INSERT_TAIL(&crp_ret_q, crp, crp_next);
  
  		if (wasempty)
  			wakeup_one(&crp_ret_q);	/* shared wait channel */
  		CRYPTO_RETQ_UNLOCK();
  	}
  }
  
  /*
   * Invoke the callback on behalf of the driver.
   */
  void
  crypto_kdone(struct cryptkop *krp)
  {
  	int wasempty;
  
  	if (krp->krp_status != 0)
  		cryptostats.cs_kerrs++;
  	CRYPTO_RETQ_LOCK();
  	wasempty = TAILQ_EMPTY(&crp_ret_kq);
  	TAILQ_INSERT_TAIL(&crp_ret_kq, krp, krp_next);
  
  	if (wasempty)
  		wakeup_one(&crp_ret_q);		/* shared wait channel */
  	CRYPTO_RETQ_UNLOCK();
  }
  
  int
  crypto_getfeat(int *featp)
  {
  	int hid, kalg, feat = 0;
  
  	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);
  }
  
  /*
   * Terminate a thread at module unload.  The process that
   * initiated this is waiting for us to signal that we're gone;
   * wake it up and exit.  We use the driver table lock to insure
   * we don't do the wakeup before they're waiting.  There is no
   * race here because the waiter sleeps on the proc lock for the
   * thread so it gets notified at the right time because of an
   * extra wakeup that's done in exit1().
   */
  static void
  crypto_finis(void *chan)
  {
  	CRYPTO_DRIVER_LOCK();
  	wakeup_one(chan);
  	CRYPTO_DRIVER_UNLOCK();
  	kthread_exit(0);
  }
  
  /*
   * Crypto thread, dispatches crypto requests.
   */
  static void
  crypto_proc(void)
  {
  	struct cryptop *crp, *submit;
  	struct cryptkop *krp;
  	struct cryptocap *cap;
  	int result, hint;
  
  	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;
  		TAILQ_FOREACH(crp, &crp_q, crp_next) {
  			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) {
  			TAILQ_REMOVE(&crp_q, submit, crp_next);
  			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;
  				TAILQ_INSERT_HEAD(&crp_q, submit, crp_next);
  				cryptostats.cs_blocks++;
  			}
  		}
  
  		/* As above, but for key ops */
  		TAILQ_FOREACH(krp, &crp_kq, krp_next) {
  			cap = crypto_checkdriver(krp->krp_hid);
  			if (cap == NULL || cap->cc_kprocess == NULL) {
  				/* Op needs to be migrated, process it. */
  				break;
  			}
  			if (!cap->cc_kqblocked)
  				break;
  		}
  		if (krp != NULL) {
  			TAILQ_REMOVE(&crp_kq, krp, krp_next);
  			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;
  				TAILQ_INSERT_HEAD(&crp_kq, krp, krp_next);
  				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.
  			 */
  			msleep(&crp_q, &crypto_q_mtx, PWAIT, "crypto_wait", 0);
  			if (cryptoproc == NULL)
  				break;
  			cryptostats.cs_intrs++;
  		}
  	}
  	CRYPTO_Q_UNLOCK();
  
  	crypto_finis(&crp_q);
  }
  
  /*
   * 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 void
  crypto_ret_proc(void)
  {
  	struct cryptop *crpt;
  	struct cryptkop *krpt;
  
  	CRYPTO_RETQ_LOCK();
  	for (;;) {
  		/* Harvest return q's for completed ops */
  		crpt = TAILQ_FIRST(&crp_ret_q);
  		if (crpt != NULL)
  			TAILQ_REMOVE(&crp_ret_q, crpt, crp_next);
  
  		krpt = TAILQ_FIRST(&crp_ret_kq);
  		if (krpt != NULL)
  			TAILQ_REMOVE(&crp_ret_kq, krpt, krp_next);
  
  		if (crpt != NULL || krpt != NULL) {
  			CRYPTO_RETQ_UNLOCK();
  			/*
  			 * Run callbacks unlocked.
  			 */
  			if (crpt != NULL) {
  #ifdef CRYPTO_TIMING
  				if (crypto_timing) {
  					/*
  					 * NB: We must copy the timestamp before
  					 * doing the callback as the cryptop is
  					 * likely to be reclaimed.
  					 */
  					struct bintime t = crpt->crp_tstamp;
  					crypto_tstat(&cryptostats.cs_cb, &t);
  					crpt->crp_callback(crpt);
  					crypto_tstat(&cryptostats.cs_finis, &t);
  				} else
  #endif
  					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.
  			 */
  			msleep(&crp_ret_q, &crypto_ret_q_mtx, PWAIT,
  				"crypto_ret_wait", 0);
  			if (cryptoretproc == NULL)
  				break;
  			cryptostats.cs_rets++;
  		}
  	}
  	CRYPTO_RETQ_UNLOCK();
  
  	crypto_finis(&crp_ret_q);
  }
  