/****************************************************************************
 * crypto/crypto.c
 * $OpenBSD: crypto.c,v 1.65 2014/07/13 23:24:47 deraadt 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.
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdbool.h>
#include <string.h>
#include <poll.h>
#include <debug.h>
#include <errno.h>
#include <crypto/cryptodev.h>
#include <nuttx/fs/fs.h>
#include <nuttx/mutex.h>
#include <nuttx/kmalloc.h>
#include <nuttx/crypto/crypto.h>

/****************************************************************************
 * Public Data
 ****************************************************************************/

FAR struct cryptocap *crypto_drivers = NULL;
int crypto_drivers_num = 0;

/****************************************************************************
 * Private Data
 ****************************************************************************/

static mutex_t g_crypto_lock = NXMUTEX_INITIALIZER;

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/* Create a new session. */

int crypto_newsession(FAR uint64_t *sid,
                      FAR struct cryptoini *cri,
                      int hard)
{
  uint32_t hid;
  uint32_t lid;
  uint32_t hid2 = -1;
  FAR struct cryptocap *cpc;
  FAR struct cryptoini *cr;
  int turn = 0;
  int err;

  if (crypto_drivers == NULL)
    {
      return -EINVAL;
    }

  nxmutex_lock(&g_crypto_lock);

  /* The algorithm we use here is pretty stupid; just use the
   * first driver that supports all the algorithms we need. Do
   * a double-pass over all the drivers, ignoring software ones
   * at first, to deal with cases of drivers that register after
   * the software one(s) --- e.g., PCMCIA crypto cards.
   *
   * XXX We need more smarts here (in real life too, but that's
   * XXX another story altogether).
   */

  do
    {
      for (hid = 0; hid < crypto_drivers_num; hid++)
        {
          cpc = &crypto_drivers[hid];

          /* If it's not initialized or has remaining sessions
           * referencing it, skip.
           */

          if (cpc->cc_newsession == NULL ||
              (cpc->cc_flags & CRYPTOCAP_F_CLEANUP))
            {
              continue;
            }

          if (cpc->cc_flags & CRYPTOCAP_F_SOFTWARE)
            {
              /* First round of search, ignore
               * software drivers.
               */

              if (turn == 0)
                {
                  continue;
                }
            }
          else
            {
              /* !CRYPTOCAP_F_SOFTWARE
               * Second round of search, only software.
               */

              if (turn == 1)
                {
                  continue;
                }
            }

          /* See if all the algorithms are supported. */

          for (cr = cri; cr; cr = cr->cri_next)
            {
              if (cpc->cc_alg[cr->cri_alg] == 0)
                {
                  break;
                }
            }

          /* If even one algorithm is not supported,
           * keep searching.
           */

          if (cr != NULL)
            {
              continue;
            }

          /* If we had a previous match, see how it compares
           * to this one. Keep "remembering" whichever is
           * the best of the two.
           */

          if (hid2 != -1)
            {
              /* Compare session numbers, pick the one
               * with the lowest.
               * XXX Need better metrics, this will
               * XXX just do un-weighted round-robin.
               */

              if (crypto_drivers[hid].cc_sessions <=
                  crypto_drivers[hid2].cc_sessions)
                {
                  hid2 = hid;
                }
            }
          else
            {
              /* Remember this one, for future
               * comparisons.
               */

              hid2 = hid;
            }
        }

      /* If we found something worth remembering, leave. The
       * side-effect is that we will always prefer a hardware
       * driver over the software one.
       */

      if (hid2 != -1)
        {
          break;
        }

      turn++;

      /* If we only want hardware drivers, don't do second pass. */
    }
  while (turn <= 2 && hard == 0);

  hid = hid2;

  /* Can't do everything in one session.
   * XXX Fix this. We need to inject a "virtual" session
   * XXX layer right about here.
   */

  if (hid == -1)
    {
      nxmutex_unlock(&g_crypto_lock);
      return -EINVAL;
    }

  /* Call the driver initialization routine. */

  lid = hid; /* Pass the driver ID. */
  err = crypto_drivers[hid].cc_newsession(&lid, cri);
  if (err == 0)
    {
      *sid = hid;
      *sid <<= 32;
      *sid |= (lid & 0xffffffff);
      crypto_drivers[hid].cc_sessions++;
    }

  nxmutex_unlock(&g_crypto_lock);
  return err;
}

/* Delete an existing session (or a reserved session on an unregistered
 * driver).
 */

int crypto_freesession(uint64_t sid)
{
  int err = 0;
  uint32_t hid;

  if (crypto_drivers == NULL)
    {
      return -EINVAL;
    }

  /* Determine two IDs. */

  hid = (sid >> 32) & 0xffffffff;

  if (hid >= crypto_drivers_num)
    {
      return -ENOENT;
    }

  nxmutex_lock(&g_crypto_lock);

  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(sid);
    }

  /* 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)
    {
      explicit_bzero(&crypto_drivers[hid], sizeof(struct cryptocap));
    }

  nxmutex_unlock(&g_crypto_lock);
  return err;
}

/* Find an empty slot. */

int crypto_get_driverid(uint8_t flags)
{
  FAR struct cryptocap *newdrv;
  int i;

  nxmutex_lock(&g_crypto_lock);

  if (crypto_drivers_num == 0)
    {
      crypto_drivers_num = CRYPTO_DRIVERS_INITIAL;
      crypto_drivers = kmm_calloc(crypto_drivers_num,
                                  sizeof(struct cryptocap));
      if (crypto_drivers == NULL)
        {
          crypto_drivers_num = 0;
          nxmutex_unlock(&g_crypto_lock);
          return -1;
        }

      bzero(crypto_drivers, crypto_drivers_num *
          sizeof(struct cryptocap));
    }

  for (i = 0; i < crypto_drivers_num; i++)
    {
      if (crypto_drivers[i].cc_process == NULL &&
          !(crypto_drivers[i].cc_flags & CRYPTOCAP_F_CLEANUP) &&
          crypto_drivers[i].cc_sessions == 0)
        {
          crypto_drivers[i].cc_sessions = 1; /* Mark */
          crypto_drivers[i].cc_flags = flags;
          nxmutex_unlock(&g_crypto_lock);
          return i;
        }
    }

  /* Out of entries, allocate some more. */

  if (i == crypto_drivers_num)
    {
      if (crypto_drivers_num >= CRYPTO_DRIVERS_MAX)
        {
          nxmutex_unlock(&g_crypto_lock);
          return -1;
        }

      newdrv = kmm_calloc(crypto_drivers_num * 2,
                          sizeof(struct cryptocap));
      if (newdrv == NULL)
        {
          nxmutex_unlock(&g_crypto_lock);
          return -1;
        }

      bcopy(crypto_drivers, newdrv,
            crypto_drivers_num * sizeof(struct cryptocap));
      bzero(&newdrv[crypto_drivers_num],
            crypto_drivers_num * sizeof(struct cryptocap));

      newdrv[i].cc_sessions = 1; /* Mark */
      newdrv[i].cc_flags = flags;
      crypto_drivers_num *= 2;

      kmm_free(crypto_drivers);
      crypto_drivers = newdrv;
      nxmutex_unlock(&g_crypto_lock);
      return i;
    }

  /* Shouldn't really get here... */

  nxmutex_unlock(&g_crypto_lock);
  return -1;
}

/* Register a crypto driver. It should be called once for each algorithm
 * supported by the driver.
 */

int crypto_kregister(uint32_t driverid, FAR int *kalg,
                     CODE int (*kprocess)(FAR struct cryptkop *))
{
  int i;

  if (driverid >= crypto_drivers_num || kalg  == NULL ||
      crypto_drivers == NULL)
    {
      return -EINVAL;
    }

  nxmutex_lock(&g_crypto_lock);

  for (i = 0; i <= CRK_ALGORITHM_MAX; i++)
    {
      /* XXX Do some performance testing to determine
       * placing.  We probably need an auxiliary data
       * structure that describes relative performances.
       */

      crypto_drivers[driverid].cc_kalg[i] = kalg[i];
    }

  crypto_drivers[driverid].cc_kprocess = kprocess;

  nxmutex_unlock(&g_crypto_lock);
  return 0;
}

/* Register a crypto driver. */

int crypto_register(uint32_t driverid, FAR int *alg,
                    CODE int (*newses)(FAR uint32_t *,
                                       FAR struct cryptoini *),
                    CODE int (*freeses)(uint64_t),
                    CODE int (*process)(FAR struct cryptop *))
{
  int i;

  if (driverid >= crypto_drivers_num || alg == NULL ||
      crypto_drivers == NULL)
    {
      return -EINVAL;
    }

  nxmutex_lock(&g_crypto_lock);

  for (i = 0; i <= CRYPTO_ALGORITHM_MAX; i++)
    {
      /* XXX Do some performance testing to determine
       * placing.  We probably need an auxiliary data
       * structure that describes relative performances.
       */

      crypto_drivers[driverid].cc_alg[i] = alg[i];
    }

  crypto_drivers[driverid].cc_newsession = newses;
  crypto_drivers[driverid].cc_process = process;
  crypto_drivers[driverid].cc_freesession = freeses;
  crypto_drivers[driverid].cc_sessions = 0; /* Unmark */

  nxmutex_unlock(&g_crypto_lock);

  return 0;
}

/* 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 being unregistered and reroute
 * the request.
 */

int crypto_unregister(uint32_t driverid, int alg)
{
  int i = CRYPTO_ALGORITHM_MAX + 1;
  uint32_t ses;

  nxmutex_lock(&g_crypto_lock);

  /* Sanity checks. */

  if (driverid >= crypto_drivers_num || crypto_drivers == NULL ||
      ((alg <= 0 || alg > CRYPTO_ALGORITHM_MAX) &&
      alg != CRYPTO_ALGORITHM_MAX + 1) ||
      crypto_drivers[driverid].cc_alg[alg] == 0)
    {
      nxmutex_unlock(&g_crypto_lock);
      return -EINVAL;
    }

  if (alg != CRYPTO_ALGORITHM_MAX + 1)
    {
      crypto_drivers[driverid].cc_alg[alg] = 0;

      /* Was this the last algorithm ? */

      for (i = 1; i <= CRYPTO_ALGORITHM_MAX; i++)
        {
          if (crypto_drivers[driverid].cc_alg[i] != 0)
            {
              break;
            }
        }
    }

  /* If a driver unregistered its last algorithm or all of them
   * (alg == CRYPTO_ALGORITHM_MAX + 1), cleanup its entry.
   */

  if (i == CRYPTO_ALGORITHM_MAX + 1 || alg == CRYPTO_ALGORITHM_MAX + 1)
    {
      ses = crypto_drivers[driverid].cc_sessions;
      bzero(&crypto_drivers[driverid], sizeof(struct cryptocap));
      if (ses != 0)
        {
          /* If there are pending sessions, just mark as invalid. */

          crypto_drivers[driverid].cc_flags |= CRYPTOCAP_F_CLEANUP;
          crypto_drivers[driverid].cc_sessions = ses;
        }
    }

  nxmutex_unlock(&g_crypto_lock);
  return 0;
}

/* Dispatch an asymmetric crypto request to the appropriate crypto devices. */

int crypto_kinvoke(FAR struct cryptkop *krp)
{
  extern int cryptodevallowsoft;
  uint32_t hid;
  int error;

  /* Sanity checks. */

  if (krp == NULL)
    {
      return -EINVAL;
    }

  nxmutex_lock(&g_crypto_lock);
  for (hid = 0; hid < crypto_drivers_num; hid++)
    {
      if ((crypto_drivers[hid].cc_flags & CRYPTOCAP_F_SOFTWARE) &&
          cryptodevallowsoft == 0)
        {
          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_status = -ENODEV;
      nxmutex_unlock(&g_crypto_lock);
      return 0;
    }

  krp->krp_hid = hid;

  crypto_drivers[hid].cc_koperations++;

  error = crypto_drivers[hid].cc_kprocess(krp);
  if (error)
    {
      krp->krp_status = error;
    }

  nxmutex_unlock(&g_crypto_lock);
  return 0;
}

/* Dispatch a crypto request to the appropriate crypto devices. */

int crypto_invoke(FAR struct cryptop *crp)
{
  FAR struct cryptodesc *crd;
  uint64_t nid;
  uint32_t hid;
  int error;

  /* Sanity checks. */

  if (crp == NULL)
    {
      return -EINVAL;
    }

  nxmutex_lock(&g_crypto_lock);
  if (crp->crp_desc == NULL || crypto_drivers == NULL)
    {
      crp->crp_etype = -EINVAL;
      nxmutex_unlock(&g_crypto_lock);
      return 0;
    }

  hid = (crp->crp_sid >> 32) & 0xffffffff;
  if (hid >= crypto_drivers_num)
    {
      goto migrate;
    }

  if (crypto_drivers[hid].cc_flags & CRYPTOCAP_F_CLEANUP)
    {
      crypto_freesession(crp->crp_sid);
      goto migrate;
    }

  if (crypto_drivers[hid].cc_process == NULL)
    {
      goto migrate;
    }

  crypto_drivers[hid].cc_operations++;
  crypto_drivers[hid].cc_bytes += crp->crp_ilen;

  error = crypto_drivers[hid].cc_process(crp);
  if (error)
    {
      if (error == -ERESTART)
        {
          /* Unregister driver and migrate session. */

          crypto_unregister(hid, CRYPTO_ALGORITHM_MAX + 1);
          goto migrate;
        }
      else
        {
          crp->crp_etype = error;
        }
    }

  nxmutex_unlock(&g_crypto_lock);
  return 0;

migrate:

  /* Migrate session. */

  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;
  nxmutex_unlock(&g_crypto_lock);
  return 0;
}

/* Release a set of crypto descriptors. */

void crypto_freereq(FAR struct cryptop *crp)
{
  FAR struct cryptodesc *crd;

  if (crp == NULL)
    {
      return;
    }

  nxmutex_lock(&g_crypto_lock);

  while ((crd = crp->crp_desc) != NULL)
    {
      crp->crp_desc = crd->crd_next;
      kmm_free(crd);
    }

  kmm_free(crp);
  nxmutex_unlock(&g_crypto_lock);
}

/* Acquire a set of crypto descriptors. */

FAR struct cryptop *crypto_getreq(int num)
{
  FAR struct cryptodesc *crd;
  FAR struct cryptop *crp;

  nxmutex_lock(&g_crypto_lock);

  crp = kmm_malloc(sizeof(struct cryptop));
  if (crp == NULL)
    {
      nxmutex_unlock(&g_crypto_lock);
      return NULL;
    }

  bzero(crp, sizeof(struct cryptop));

  while (num--)
    {
      crd = kmm_calloc(1, sizeof(struct cryptodesc));
      if (crd == NULL)
        {
          nxmutex_unlock(&g_crypto_lock);
          crypto_freereq(crp);
          return NULL;
        }

      crd->crd_next = crp->crp_desc;
      crp->crp_desc = crd;
    }

  nxmutex_unlock(&g_crypto_lock);
  return crp;
}

int crypto_getfeat(FAR int *featp)
{
  extern int cryptodevallowsoft;
  extern int userasymcrypto;
  int hid;
  int kalg;
  int feat = 0;

  if (userasymcrypto == 0)
    {
      goto out;
    }

  for (hid = 0; hid < crypto_drivers_num; hid++)
    {
      if ((crypto_drivers[hid].cc_flags & CRYPTOCAP_F_SOFTWARE) &&
          cryptodevallowsoft == 0)
        {
          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;
            }
        }
    }

out:
  *featp = feat;
  return 0;
}

int up_cryptoinitialize(void)
{
#ifdef CONFIG_CRYPTO_ALGTEST
  int ret = crypto_test();
  if (ret)
    {
      crypterr("ERROR: crypto test failed\n");
    }
  else
    {
      cryptinfo("crypto test OK\n");
    }

  return ret;
#else
  return OK;
#endif
}