/*

   * xfrm_policy.c
   *
   * Changes:
   *	Mitsuru KANDA @USAGI
   * 	Kazunori MIYAZAWA @USAGI
   * 	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
   * 		IPv6 support
   * 	Kazunori MIYAZAWA @USAGI
   * 	YOSHIFUJI Hideaki
   * 		Split up af-specific portion
   *	Derek Atkins <derek@ihtfp.com>		Add the post_input processor

   *

   */

  #include <linux/err.h>

  #include <linux/slab.h>
  #include <linux/kmod.h>
  #include <linux/list.h>
  #include <linux/spinlock.h>
  #include <linux/workqueue.h>
  #include <linux/notifier.h>
  #include <linux/netdevice.h>

  #include <linux/netfilter.h>

  #include <linux/module.h>

  #include <linux/cache.h>

  #include <linux/cpu.h>

  #include <linux/audit.h>

  #include <net/dst.h>

  #include <net/flow.h>

  #include <net/xfrm.h>
  #include <net/ip.h>

  #ifdef CONFIG_XFRM_STATISTICS
  #include <net/snmp.h>
  #endif

  #include "xfrm_hash.h"

  #define XFRM_QUEUE_TMO_MIN ((unsigned)(HZ/10))
  #define XFRM_QUEUE_TMO_MAX ((unsigned)(60*HZ))
  #define XFRM_MAX_QUEUE_LEN	100

  struct xfrm_flo {
  	struct dst_entry *dst_orig;
  	u8 flags;
  };

  static DEFINE_PER_CPU(struct xfrm_dst *, xfrm_last_dst);
  static struct work_struct *xfrm_pcpu_work __read_mostly;

  static DEFINE_SPINLOCK(xfrm_policy_afinfo_lock);

  static struct xfrm_policy_afinfo const __rcu *xfrm_policy_afinfo[AF_INET6 + 1]

  						__read_mostly;

  static struct kmem_cache *xfrm_dst_cache __read_mostly;

  static __read_mostly seqcount_t xfrm_policy_hash_generation;

  static void xfrm_init_pmtu(struct dst_entry *dst);

  static int stale_bundle(struct dst_entry *dst);

  static int xfrm_bundle_ok(struct xfrm_dst *xdst);

  static void xfrm_policy_queue_process(struct timer_list *t);

  static void __xfrm_policy_link(struct xfrm_policy *pol, int dir);

  static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
  						int dir);

  static inline bool xfrm_pol_hold_rcu(struct xfrm_policy *policy)
  {

  	return refcount_inc_not_zero(&policy->refcnt);

  }

  static inline bool

  __xfrm4_selector_match(const struct xfrm_selector *sel, const struct flowi *fl)

  {

  	const struct flowi4 *fl4 = &fl->u.ip4;

  	return  addr4_match(fl4->daddr, sel->daddr.a4, sel->prefixlen_d) &&
  		addr4_match(fl4->saddr, sel->saddr.a4, sel->prefixlen_s) &&

  		!((xfrm_flowi_dport(fl, &fl4->uli) ^ sel->dport) & sel->dport_mask) &&
  		!((xfrm_flowi_sport(fl, &fl4->uli) ^ sel->sport) & sel->sport_mask) &&
  		(fl4->flowi4_proto == sel->proto || !sel->proto) &&
  		(fl4->flowi4_oif == sel->ifindex || !sel->ifindex);

  }

  static inline bool

  __xfrm6_selector_match(const struct xfrm_selector *sel, const struct flowi *fl)

  {

  	const struct flowi6 *fl6 = &fl->u.ip6;
  
  	return  addr_match(&fl6->daddr, &sel->daddr, sel->prefixlen_d) &&
  		addr_match(&fl6->saddr, &sel->saddr, sel->prefixlen_s) &&
  		!((xfrm_flowi_dport(fl, &fl6->uli) ^ sel->dport) & sel->dport_mask) &&
  		!((xfrm_flowi_sport(fl, &fl6->uli) ^ sel->sport) & sel->sport_mask) &&
  		(fl6->flowi6_proto == sel->proto || !sel->proto) &&
  		(fl6->flowi6_oif == sel->ifindex || !sel->ifindex);

  }

  bool xfrm_selector_match(const struct xfrm_selector *sel, const struct flowi *fl,
  			 unsigned short family)

  {
  	switch (family) {
  	case AF_INET:
  		return __xfrm4_selector_match(sel, fl);
  	case AF_INET6:
  		return __xfrm6_selector_match(sel, fl);
  	}

  	return false;

  }

  static const struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)

  {

  	const struct xfrm_policy_afinfo *afinfo;

  	if (unlikely(family >= ARRAY_SIZE(xfrm_policy_afinfo)))

  		return NULL;
  	rcu_read_lock();
  	afinfo = rcu_dereference(xfrm_policy_afinfo[family]);
  	if (unlikely(!afinfo))
  		rcu_read_unlock();
  	return afinfo;
  }

  struct dst_entry *__xfrm_dst_lookup(struct net *net, int tos, int oif,
  				    const xfrm_address_t *saddr,
  				    const xfrm_address_t *daddr,

  				    int family, u32 mark)

  {

  	const struct xfrm_policy_afinfo *afinfo;

  	struct dst_entry *dst;
  
  	afinfo = xfrm_policy_get_afinfo(family);
  	if (unlikely(afinfo == NULL))
  		return ERR_PTR(-EAFNOSUPPORT);

  	dst = afinfo->dst_lookup(net, tos, oif, saddr, daddr, mark);

  	rcu_read_unlock();

  
  	return dst;
  }

  EXPORT_SYMBOL(__xfrm_dst_lookup);

  static inline struct dst_entry *xfrm_dst_lookup(struct xfrm_state *x,
  						int tos, int oif,

  						xfrm_address_t *prev_saddr,
  						xfrm_address_t *prev_daddr,

  						int family, u32 mark)

  {

  	struct net *net = xs_net(x);

  	xfrm_address_t *saddr = &x->props.saddr;
  	xfrm_address_t *daddr = &x->id.daddr;

  	struct dst_entry *dst;

  	if (x->type->flags & XFRM_TYPE_LOCAL_COADDR) {

  		saddr = x->coaddr;

  		daddr = prev_daddr;
  	}
  	if (x->type->flags & XFRM_TYPE_REMOTE_COADDR) {
  		saddr = prev_saddr;

  		daddr = x->coaddr;

  	}

  	dst = __xfrm_dst_lookup(net, tos, oif, saddr, daddr, family, mark);

  
  	if (!IS_ERR(dst)) {
  		if (prev_saddr != saddr)
  			memcpy(prev_saddr, saddr,  sizeof(*prev_saddr));
  		if (prev_daddr != daddr)
  			memcpy(prev_daddr, daddr,  sizeof(*prev_daddr));
  	}

  	return dst;

  }

  static inline unsigned long make_jiffies(long secs)
  {
  	if (secs >= (MAX_SCHEDULE_TIMEOUT-1)/HZ)
  		return MAX_SCHEDULE_TIMEOUT-1;
  	else

  		return secs*HZ;

  }

  static void xfrm_policy_timer(struct timer_list *t)

  {

  	struct xfrm_policy *xp = from_timer(xp, t, timer);

  	unsigned long now = get_seconds();

  	long next = LONG_MAX;
  	int warn = 0;
  	int dir;
  
  	read_lock(&xp->lock);

  	if (unlikely(xp->walk.dead))

  		goto out;

  	dir = xfrm_policy_id2dir(xp->index);

  
  	if (xp->lft.hard_add_expires_seconds) {
  		long tmo = xp->lft.hard_add_expires_seconds +
  			xp->curlft.add_time - now;
  		if (tmo <= 0)
  			goto expired;
  		if (tmo < next)
  			next = tmo;
  	}
  	if (xp->lft.hard_use_expires_seconds) {
  		long tmo = xp->lft.hard_use_expires_seconds +
  			(xp->curlft.use_time ? : xp->curlft.add_time) - now;
  		if (tmo <= 0)
  			goto expired;
  		if (tmo < next)
  			next = tmo;
  	}
  	if (xp->lft.soft_add_expires_seconds) {
  		long tmo = xp->lft.soft_add_expires_seconds +
  			xp->curlft.add_time - now;
  		if (tmo <= 0) {
  			warn = 1;
  			tmo = XFRM_KM_TIMEOUT;
  		}
  		if (tmo < next)
  			next = tmo;
  	}
  	if (xp->lft.soft_use_expires_seconds) {
  		long tmo = xp->lft.soft_use_expires_seconds +
  			(xp->curlft.use_time ? : xp->curlft.add_time) - now;
  		if (tmo <= 0) {
  			warn = 1;
  			tmo = XFRM_KM_TIMEOUT;
  		}
  		if (tmo < next)
  			next = tmo;
  	}
  
  	if (warn)

  		km_policy_expired(xp, dir, 0, 0);

  	if (next != LONG_MAX &&
  	    !mod_timer(&xp->timer, jiffies + make_jiffies(next)))
  		xfrm_pol_hold(xp);
  
  out:
  	read_unlock(&xp->lock);
  	xfrm_pol_put(xp);
  	return;
  
  expired:
  	read_unlock(&xp->lock);

  	if (!xfrm_policy_delete(xp, dir))

  		km_policy_expired(xp, dir, 1, 0);

  	xfrm_pol_put(xp);
  }

  /* Allocate xfrm_policy. Not used here, it is supposed to be used by pfkeyv2
   * SPD calls.
   */

  struct xfrm_policy *xfrm_policy_alloc(struct net *net, gfp_t gfp)

  {
  	struct xfrm_policy *policy;

  	policy = kzalloc(sizeof(struct xfrm_policy), gfp);

  
  	if (policy) {

  		write_pnet(&policy->xp_net, net);

  		INIT_LIST_HEAD(&policy->walk.all);

  		INIT_HLIST_NODE(&policy->bydst);
  		INIT_HLIST_NODE(&policy->byidx);

  		rwlock_init(&policy->lock);

  		refcount_set(&policy->refcnt, 1);

  		skb_queue_head_init(&policy->polq.hold_queue);

  		timer_setup(&policy->timer, xfrm_policy_timer, 0);
  		timer_setup(&policy->polq.hold_timer,
  			    xfrm_policy_queue_process, 0);

  	}
  	return policy;
  }
  EXPORT_SYMBOL(xfrm_policy_alloc);

  static void xfrm_policy_destroy_rcu(struct rcu_head *head)
  {
  	struct xfrm_policy *policy = container_of(head, struct xfrm_policy, rcu);
  
  	security_xfrm_policy_free(policy->security);
  	kfree(policy);
  }

  /* Destroy xfrm_policy: descendant resources must be released to this moment. */

  void xfrm_policy_destroy(struct xfrm_policy *policy)

  {

  	BUG_ON(!policy->walk.dead);

  	if (del_timer(&policy->timer) || del_timer(&policy->polq.hold_timer))

  		BUG();

  	call_rcu(&policy->rcu, xfrm_policy_destroy_rcu);

  }

  EXPORT_SYMBOL(xfrm_policy_destroy);

  /* Rule must be locked. Release descendant resources, announce

   * entry dead. The rule must be unlinked from lists to the moment.
   */
  
  static void xfrm_policy_kill(struct xfrm_policy *policy)
  {

  	policy->walk.dead = 1;

  	atomic_inc(&policy->genid);

  	if (del_timer(&policy->polq.hold_timer))
  		xfrm_pol_put(policy);

  	skb_queue_purge(&policy->polq.hold_queue);

  	if (del_timer(&policy->timer))
  		xfrm_pol_put(policy);
  
  	xfrm_pol_put(policy);

  }

  static unsigned int xfrm_policy_hashmax __read_mostly = 1 * 1024 * 1024;

  static inline unsigned int idx_hash(struct net *net, u32 index)

  {

  	return __idx_hash(index, net->xfrm.policy_idx_hmask);

  }

  /* calculate policy hash thresholds */
  static void __get_hash_thresh(struct net *net,
  			      unsigned short family, int dir,
  			      u8 *dbits, u8 *sbits)
  {
  	switch (family) {
  	case AF_INET:
  		*dbits = net->xfrm.policy_bydst[dir].dbits4;
  		*sbits = net->xfrm.policy_bydst[dir].sbits4;
  		break;
  
  	case AF_INET6:
  		*dbits = net->xfrm.policy_bydst[dir].dbits6;
  		*sbits = net->xfrm.policy_bydst[dir].sbits6;
  		break;
  
  	default:
  		*dbits = 0;
  		*sbits = 0;
  	}
  }

  static struct hlist_head *policy_hash_bysel(struct net *net,
  					    const struct xfrm_selector *sel,
  					    unsigned short family, int dir)

  {

  	unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;

  	unsigned int hash;
  	u8 dbits;
  	u8 sbits;
  
  	__get_hash_thresh(net, family, dir, &dbits, &sbits);
  	hash = __sel_hash(sel, family, hmask, dbits, sbits);

  	if (hash == hmask + 1)
  		return &net->xfrm.policy_inexact[dir];
  
  	return rcu_dereference_check(net->xfrm.policy_bydst[dir].table,
  		     lockdep_is_held(&net->xfrm.xfrm_policy_lock)) + hash;

  }

  static struct hlist_head *policy_hash_direct(struct net *net,
  					     const xfrm_address_t *daddr,
  					     const xfrm_address_t *saddr,
  					     unsigned short family, int dir)

  {

  	unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;

  	unsigned int hash;
  	u8 dbits;
  	u8 sbits;
  
  	__get_hash_thresh(net, family, dir, &dbits, &sbits);
  	hash = __addr_hash(daddr, saddr, family, hmask, dbits, sbits);

  	return rcu_dereference_check(net->xfrm.policy_bydst[dir].table,
  		     lockdep_is_held(&net->xfrm.xfrm_policy_lock)) + hash;

  }

  static void xfrm_dst_hash_transfer(struct net *net,
  				   struct hlist_head *list,

  				   struct hlist_head *ndsttable,

  				   unsigned int nhashmask,
  				   int dir)

  {

  	struct hlist_node *tmp, *entry0 = NULL;

  	struct xfrm_policy *pol;

  	unsigned int h0 = 0;

  	u8 dbits;
  	u8 sbits;

  redo:

  	hlist_for_each_entry_safe(pol, tmp, list, bydst) {

  		unsigned int h;

  		__get_hash_thresh(net, pol->family, dir, &dbits, &sbits);

  		h = __addr_hash(&pol->selector.daddr, &pol->selector.saddr,

  				pol->family, nhashmask, dbits, sbits);

  		if (!entry0) {

  			hlist_del_rcu(&pol->bydst);
  			hlist_add_head_rcu(&pol->bydst, ndsttable + h);

  			h0 = h;
  		} else {
  			if (h != h0)
  				continue;

  			hlist_del_rcu(&pol->bydst);
  			hlist_add_behind_rcu(&pol->bydst, entry0);

  		}

  		entry0 = &pol->bydst;

  	}
  	if (!hlist_empty(list)) {
  		entry0 = NULL;
  		goto redo;

  	}
  }
  
  static void xfrm_idx_hash_transfer(struct hlist_head *list,
  				   struct hlist_head *nidxtable,
  				   unsigned int nhashmask)
  {

  	struct hlist_node *tmp;

  	struct xfrm_policy *pol;

  	hlist_for_each_entry_safe(pol, tmp, list, byidx) {

  		unsigned int h;
  
  		h = __idx_hash(pol->index, nhashmask);
  		hlist_add_head(&pol->byidx, nidxtable+h);
  	}
  }
  
  static unsigned long xfrm_new_hash_mask(unsigned int old_hmask)
  {
  	return ((old_hmask + 1) << 1) - 1;
  }

  static void xfrm_bydst_resize(struct net *net, int dir)

  {

  	unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;

  	unsigned int nhashmask = xfrm_new_hash_mask(hmask);
  	unsigned int nsize = (nhashmask + 1) * sizeof(struct hlist_head);

  	struct hlist_head *ndst = xfrm_hash_alloc(nsize);

  	struct hlist_head *odst;

  	int i;
  
  	if (!ndst)
  		return;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	write_seqcount_begin(&xfrm_policy_hash_generation);
  
  	odst = rcu_dereference_protected(net->xfrm.policy_bydst[dir].table,
  				lockdep_is_held(&net->xfrm.xfrm_policy_lock));

  	odst = rcu_dereference_protected(net->xfrm.policy_bydst[dir].table,
  				lockdep_is_held(&net->xfrm.xfrm_policy_lock));

  	for (i = hmask; i >= 0; i--)

  		xfrm_dst_hash_transfer(net, odst + i, ndst, nhashmask, dir);

  	rcu_assign_pointer(net->xfrm.policy_bydst[dir].table, ndst);

  	net->xfrm.policy_bydst[dir].hmask = nhashmask;

  	write_seqcount_end(&xfrm_policy_hash_generation);

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	synchronize_rcu();

  	xfrm_hash_free(odst, (hmask + 1) * sizeof(struct hlist_head));

  }

  static void xfrm_byidx_resize(struct net *net, int total)

  {

  	unsigned int hmask = net->xfrm.policy_idx_hmask;

  	unsigned int nhashmask = xfrm_new_hash_mask(hmask);
  	unsigned int nsize = (nhashmask + 1) * sizeof(struct hlist_head);

  	struct hlist_head *oidx = net->xfrm.policy_byidx;

  	struct hlist_head *nidx = xfrm_hash_alloc(nsize);

  	int i;
  
  	if (!nidx)
  		return;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  
  	for (i = hmask; i >= 0; i--)
  		xfrm_idx_hash_transfer(oidx + i, nidx, nhashmask);

  	net->xfrm.policy_byidx = nidx;
  	net->xfrm.policy_idx_hmask = nhashmask;

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	xfrm_hash_free(oidx, (hmask + 1) * sizeof(struct hlist_head));

  }

  static inline int xfrm_bydst_should_resize(struct net *net, int dir, int *total)

  {

  	unsigned int cnt = net->xfrm.policy_count[dir];
  	unsigned int hmask = net->xfrm.policy_bydst[dir].hmask;

  
  	if (total)
  		*total += cnt;
  
  	if ((hmask + 1) < xfrm_policy_hashmax &&
  	    cnt > hmask)
  		return 1;
  
  	return 0;
  }

  static inline int xfrm_byidx_should_resize(struct net *net, int total)

  {

  	unsigned int hmask = net->xfrm.policy_idx_hmask;

  
  	if ((hmask + 1) < xfrm_policy_hashmax &&
  	    total > hmask)
  		return 1;
  
  	return 0;
  }

  void xfrm_spd_getinfo(struct net *net, struct xfrmk_spdinfo *si)

  {

  	si->incnt = net->xfrm.policy_count[XFRM_POLICY_IN];
  	si->outcnt = net->xfrm.policy_count[XFRM_POLICY_OUT];
  	si->fwdcnt = net->xfrm.policy_count[XFRM_POLICY_FWD];
  	si->inscnt = net->xfrm.policy_count[XFRM_POLICY_IN+XFRM_POLICY_MAX];
  	si->outscnt = net->xfrm.policy_count[XFRM_POLICY_OUT+XFRM_POLICY_MAX];
  	si->fwdscnt = net->xfrm.policy_count[XFRM_POLICY_FWD+XFRM_POLICY_MAX];
  	si->spdhcnt = net->xfrm.policy_idx_hmask;

  	si->spdhmcnt = xfrm_policy_hashmax;

  }
  EXPORT_SYMBOL(xfrm_spd_getinfo);

  static DEFINE_MUTEX(hash_resize_mutex);

  static void xfrm_hash_resize(struct work_struct *work)

  {

  	struct net *net = container_of(work, struct net, xfrm.policy_hash_work);

  	int dir, total;
  
  	mutex_lock(&hash_resize_mutex);
  
  	total = 0;

  	for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {

  		if (xfrm_bydst_should_resize(net, dir, &total))
  			xfrm_bydst_resize(net, dir);

  	}

  	if (xfrm_byidx_should_resize(net, total))
  		xfrm_byidx_resize(net, total);

  
  	mutex_unlock(&hash_resize_mutex);
  }

  static void xfrm_hash_rebuild(struct work_struct *work)
  {
  	struct net *net = container_of(work, struct net,
  				       xfrm.policy_hthresh.work);
  	unsigned int hmask;
  	struct xfrm_policy *pol;
  	struct xfrm_policy *policy;
  	struct hlist_head *chain;
  	struct hlist_head *odst;
  	struct hlist_node *newpos;
  	int i;
  	int dir;
  	unsigned seq;
  	u8 lbits4, rbits4, lbits6, rbits6;
  
  	mutex_lock(&hash_resize_mutex);
  
  	/* read selector prefixlen thresholds */
  	do {
  		seq = read_seqbegin(&net->xfrm.policy_hthresh.lock);
  
  		lbits4 = net->xfrm.policy_hthresh.lbits4;
  		rbits4 = net->xfrm.policy_hthresh.rbits4;
  		lbits6 = net->xfrm.policy_hthresh.lbits6;
  		rbits6 = net->xfrm.policy_hthresh.rbits6;
  	} while (read_seqretry(&net->xfrm.policy_hthresh.lock, seq));

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  
  	/* reset the bydst and inexact table in all directions */

  	for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {

  		INIT_HLIST_HEAD(&net->xfrm.policy_inexact[dir]);
  		hmask = net->xfrm.policy_bydst[dir].hmask;
  		odst = net->xfrm.policy_bydst[dir].table;
  		for (i = hmask; i >= 0; i--)
  			INIT_HLIST_HEAD(odst + i);
  		if ((dir & XFRM_POLICY_MASK) == XFRM_POLICY_OUT) {
  			/* dir out => dst = remote, src = local */
  			net->xfrm.policy_bydst[dir].dbits4 = rbits4;
  			net->xfrm.policy_bydst[dir].sbits4 = lbits4;
  			net->xfrm.policy_bydst[dir].dbits6 = rbits6;
  			net->xfrm.policy_bydst[dir].sbits6 = lbits6;
  		} else {
  			/* dir in/fwd => dst = local, src = remote */
  			net->xfrm.policy_bydst[dir].dbits4 = lbits4;
  			net->xfrm.policy_bydst[dir].sbits4 = rbits4;
  			net->xfrm.policy_bydst[dir].dbits6 = lbits6;
  			net->xfrm.policy_bydst[dir].sbits6 = rbits6;
  		}
  	}
  
  	/* re-insert all policies by order of creation */
  	list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) {

  		if (xfrm_policy_id2dir(policy->index) >= XFRM_POLICY_MAX) {
  			/* skip socket policies */
  			continue;
  		}

  		newpos = NULL;
  		chain = policy_hash_bysel(net, &policy->selector,
  					  policy->family,
  					  xfrm_policy_id2dir(policy->index));
  		hlist_for_each_entry(pol, chain, bydst) {
  			if (policy->priority >= pol->priority)
  				newpos = &pol->bydst;
  			else
  				break;
  		}
  		if (newpos)
  			hlist_add_behind(&policy->bydst, newpos);
  		else
  			hlist_add_head(&policy->bydst, chain);
  	}

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  
  	mutex_unlock(&hash_resize_mutex);
  }
  
  void xfrm_policy_hash_rebuild(struct net *net)
  {
  	schedule_work(&net->xfrm.policy_hthresh.work);
  }
  EXPORT_SYMBOL(xfrm_policy_hash_rebuild);

  /* Generate new index... KAME seems to generate them ordered by cost
   * of an absolute inpredictability of ordering of rules. This will not pass. */

  static u32 xfrm_gen_index(struct net *net, int dir, u32 index)

  {

  	static u32 idx_generator;
  
  	for (;;) {

  		struct hlist_head *list;
  		struct xfrm_policy *p;
  		u32 idx;
  		int found;

  		if (!index) {
  			idx = (idx_generator | dir);
  			idx_generator += 8;
  		} else {
  			idx = index;
  			index = 0;
  		}

  		if (idx == 0)
  			idx = 8;

  		list = net->xfrm.policy_byidx + idx_hash(net, idx);

  		found = 0;

  		hlist_for_each_entry(p, list, byidx) {

  			if (p->index == idx) {
  				found = 1;

  				break;

  			}

  		}

  		if (!found)

  			return idx;
  	}
  }

  static inline int selector_cmp(struct xfrm_selector *s1, struct xfrm_selector *s2)
  {
  	u32 *p1 = (u32 *) s1;
  	u32 *p2 = (u32 *) s2;
  	int len = sizeof(struct xfrm_selector) / sizeof(u32);
  	int i;
  
  	for (i = 0; i < len; i++) {
  		if (p1[i] != p2[i])
  			return 1;
  	}
  
  	return 0;
  }

  static void xfrm_policy_requeue(struct xfrm_policy *old,
  				struct xfrm_policy *new)
  {
  	struct xfrm_policy_queue *pq = &old->polq;
  	struct sk_buff_head list;

  	if (skb_queue_empty(&pq->hold_queue))
  		return;

  	__skb_queue_head_init(&list);
  
  	spin_lock_bh(&pq->hold_queue.lock);
  	skb_queue_splice_init(&pq->hold_queue, &list);

  	if (del_timer(&pq->hold_timer))
  		xfrm_pol_put(old);

  	spin_unlock_bh(&pq->hold_queue.lock);

  	pq = &new->polq;
  
  	spin_lock_bh(&pq->hold_queue.lock);
  	skb_queue_splice(&list, &pq->hold_queue);
  	pq->timeout = XFRM_QUEUE_TMO_MIN;

  	if (!mod_timer(&pq->hold_timer, jiffies))
  		xfrm_pol_hold(new);

  	spin_unlock_bh(&pq->hold_queue.lock);
  }

  static bool xfrm_policy_mark_match(struct xfrm_policy *policy,
  				   struct xfrm_policy *pol)
  {
  	u32 mark = policy->mark.v & policy->mark.m;
  
  	if (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m)
  		return true;
  
  	if ((mark & pol->mark.m) == pol->mark.v &&
  	    policy->priority == pol->priority)
  		return true;
  
  	return false;
  }

  int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
  {

  	struct net *net = xp_net(policy);

  	struct xfrm_policy *pol;
  	struct xfrm_policy *delpol;
  	struct hlist_head *chain;

  	struct hlist_node *newpos;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	chain = policy_hash_bysel(net, &policy->selector, policy->family, dir);

  	delpol = NULL;
  	newpos = NULL;

  	hlist_for_each_entry(pol, chain, bydst) {

  		if (pol->type == policy->type &&

  		    !selector_cmp(&pol->selector, &policy->selector) &&

  		    xfrm_policy_mark_match(policy, pol) &&

  		    xfrm_sec_ctx_match(pol->security, policy->security) &&
  		    !WARN_ON(delpol)) {

  			if (excl) {

  				spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  				return -EEXIST;
  			}

  			delpol = pol;
  			if (policy->priority > pol->priority)
  				continue;
  		} else if (policy->priority >= pol->priority) {

  			newpos = &pol->bydst;

  			continue;
  		}

  		if (delpol)
  			break;

  	}
  	if (newpos)

  		hlist_add_behind(&policy->bydst, newpos);

  	else
  		hlist_add_head(&policy->bydst, chain);

  	__xfrm_policy_link(policy, dir);

  
  	/* After previous checking, family can either be AF_INET or AF_INET6 */
  	if (policy->family == AF_INET)
  		rt_genid_bump_ipv4(net);
  	else
  		rt_genid_bump_ipv6(net);

  	if (delpol) {
  		xfrm_policy_requeue(delpol, policy);

  		__xfrm_policy_unlink(delpol, dir);

  	}

  	policy->index = delpol ? delpol->index : xfrm_gen_index(net, dir, policy->index);

  	hlist_add_head(&policy->byidx, net->xfrm.policy_byidx+idx_hash(net, policy->index));

  	policy->curlft.add_time = get_seconds();

  	policy->curlft.use_time = 0;
  	if (!mod_timer(&policy->timer, jiffies + HZ))
  		xfrm_pol_hold(policy);

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	if (delpol)

  		xfrm_policy_kill(delpol);

  	else if (xfrm_bydst_should_resize(net, dir, NULL))
  		schedule_work(&net->xfrm.policy_hash_work);

  	return 0;
  }
  EXPORT_SYMBOL(xfrm_policy_insert);

  struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u8 type,
  					  int dir, struct xfrm_selector *sel,

  					  struct xfrm_sec_ctx *ctx, int delete,
  					  int *err)

  {

  	struct xfrm_policy *pol, *ret;
  	struct hlist_head *chain;

  	*err = 0;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	chain = policy_hash_bysel(net, sel, sel->family, dir);

  	ret = NULL;

  	hlist_for_each_entry(pol, chain, bydst) {

  		if (pol->type == type &&

  		    (mark & pol->mark.m) == pol->mark.v &&

  		    !selector_cmp(sel, &pol->selector) &&
  		    xfrm_sec_ctx_match(ctx, pol->security)) {

  			xfrm_pol_hold(pol);

  			if (delete) {

  				*err = security_xfrm_policy_delete(
  								pol->security);

  				if (*err) {

  					spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  					return pol;
  				}

  				__xfrm_policy_unlink(pol, dir);

  			}
  			ret = pol;

  			break;
  		}
  	}

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	if (ret && delete)

  		xfrm_policy_kill(ret);

  	return ret;

  }

  EXPORT_SYMBOL(xfrm_policy_bysel_ctx);

  struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u8 type,
  				     int dir, u32 id, int delete, int *err)

  {

  	struct xfrm_policy *pol, *ret;
  	struct hlist_head *chain;

  	*err = -ENOENT;
  	if (xfrm_policy_id2dir(id) != dir)
  		return NULL;

  	*err = 0;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	chain = net->xfrm.policy_byidx + idx_hash(net, id);

  	ret = NULL;

  	hlist_for_each_entry(pol, chain, byidx) {

  		if (pol->type == type && pol->index == id &&
  		    (mark & pol->mark.m) == pol->mark.v) {

  			xfrm_pol_hold(pol);

  			if (delete) {

  				*err = security_xfrm_policy_delete(
  								pol->security);

  				if (*err) {

  					spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  					return pol;
  				}

  				__xfrm_policy_unlink(pol, dir);

  			}
  			ret = pol;

  			break;
  		}
  	}

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	if (ret && delete)

  		xfrm_policy_kill(ret);

  	return ret;

  }
  EXPORT_SYMBOL(xfrm_policy_byid);

  #ifdef CONFIG_SECURITY_NETWORK_XFRM
  static inline int

  xfrm_policy_flush_secctx_check(struct net *net, u8 type, bool task_valid)

  {

  	int dir, err = 0;
  
  	for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
  		struct xfrm_policy *pol;

  		int i;

  		hlist_for_each_entry(pol,

  				     &net->xfrm.policy_inexact[dir], bydst) {

  			if (pol->type != type)
  				continue;

  			err = security_xfrm_policy_delete(pol->security);

  			if (err) {

  				xfrm_audit_policy_delete(pol, 0, task_valid);

  				return err;
  			}

  		}

  		for (i = net->xfrm.policy_bydst[dir].hmask; i >= 0; i--) {

  			hlist_for_each_entry(pol,

  					     net->xfrm.policy_bydst[dir].table + i,

  					     bydst) {
  				if (pol->type != type)
  					continue;

  				err = security_xfrm_policy_delete(
  								pol->security);

  				if (err) {

  					xfrm_audit_policy_delete(pol, 0,

  								 task_valid);

  					return err;
  				}
  			}
  		}
  	}
  	return err;
  }
  #else
  static inline int

  xfrm_policy_flush_secctx_check(struct net *net, u8 type, bool task_valid)

  {
  	return 0;
  }
  #endif

  int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)

  {

  	int dir, err = 0, cnt = 0;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	err = xfrm_policy_flush_secctx_check(net, type, task_valid);

  	if (err)
  		goto out;

  	for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {

  		struct xfrm_policy *pol;

  		int i;

  
  	again1:

  		hlist_for_each_entry(pol,

  				     &net->xfrm.policy_inexact[dir], bydst) {

  			if (pol->type != type)
  				continue;

  			__xfrm_policy_unlink(pol, dir);

  			spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  			cnt++;

  			xfrm_audit_policy_delete(pol, 1, task_valid);

  			xfrm_policy_kill(pol);

  			spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  			goto again1;
  		}

  		for (i = net->xfrm.policy_bydst[dir].hmask; i >= 0; i--) {

  	again2:

  			hlist_for_each_entry(pol,

  					     net->xfrm.policy_bydst[dir].table + i,

  					     bydst) {
  				if (pol->type != type)
  					continue;

  				__xfrm_policy_unlink(pol, dir);

  				spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  				cnt++;

  				xfrm_audit_policy_delete(pol, 1, task_valid);

  				xfrm_policy_kill(pol);

  				spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  				goto again2;
  			}

  		}

  	}

  	if (!cnt)
  		err = -ESRCH;

  	else
  		xfrm_policy_cache_flush();

  out:

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	return err;

  }
  EXPORT_SYMBOL(xfrm_policy_flush);

  int xfrm_policy_walk(struct net *net, struct xfrm_policy_walk *walk,

  		     int (*func)(struct xfrm_policy *, int, int, void*),

  		     void *data)
  {

  	struct xfrm_policy *pol;
  	struct xfrm_policy_walk_entry *x;

  	int error = 0;
  
  	if (walk->type >= XFRM_POLICY_TYPE_MAX &&
  	    walk->type != XFRM_POLICY_TYPE_ANY)
  		return -EINVAL;

  	if (list_empty(&walk->walk.all) && walk->seq != 0)

  		return 0;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	if (list_empty(&walk->walk.all))

  		x = list_first_entry(&net->xfrm.policy_all, struct xfrm_policy_walk_entry, all);

  	else

  		x = list_first_entry(&walk->walk.all,
  				     struct xfrm_policy_walk_entry, all);

  	list_for_each_entry_from(x, &net->xfrm.policy_all, all) {

  		if (x->dead)

  			continue;

  		pol = container_of(x, struct xfrm_policy, walk);
  		if (walk->type != XFRM_POLICY_TYPE_ANY &&
  		    walk->type != pol->type)
  			continue;
  		error = func(pol, xfrm_policy_id2dir(pol->index),
  			     walk->seq, data);
  		if (error) {
  			list_move_tail(&walk->walk.all, &x->all);
  			goto out;

  		}

  		walk->seq++;

  	}

  	if (walk->seq == 0) {

  		error = -ENOENT;
  		goto out;
  	}

  	list_del_init(&walk->walk.all);

  out:

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	return error;
  }
  EXPORT_SYMBOL(xfrm_policy_walk);

  void xfrm_policy_walk_init(struct xfrm_policy_walk *walk, u8 type)
  {
  	INIT_LIST_HEAD(&walk->walk.all);
  	walk->walk.dead = 1;
  	walk->type = type;
  	walk->seq = 0;
  }
  EXPORT_SYMBOL(xfrm_policy_walk_init);

  void xfrm_policy_walk_done(struct xfrm_policy_walk *walk, struct net *net)

  {
  	if (list_empty(&walk->walk.all))
  		return;

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock); /*FIXME where is net? */

  	list_del(&walk->walk.all);

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  }
  EXPORT_SYMBOL(xfrm_policy_walk_done);

  /*
   * Find policy to apply to this flow.
   *
   * Returns 0 if policy found, else an -errno.
   */

  static int xfrm_policy_match(const struct xfrm_policy *pol,
  			     const struct flowi *fl,

  			     u8 type, u16 family, int dir)

  {

  	const struct xfrm_selector *sel = &pol->selector;

  	int ret = -ESRCH;
  	bool match;

  	if (pol->family != family ||

  	    (fl->flowi_mark & pol->mark.m) != pol->mark.v ||

  	    pol->type != type)

  		return ret;

  	match = xfrm_selector_match(sel, fl, family);

  	if (match)

  		ret = security_xfrm_policy_lookup(pol->security, fl->flowi_secid,

  						  dir);

  	return ret;

  }

  static struct xfrm_policy *xfrm_policy_lookup_bytype(struct net *net, u8 type,

  						     const struct flowi *fl,

  						     u16 family, u8 dir)
  {

  	int err;

  	struct xfrm_policy *pol, *ret;

  	const xfrm_address_t *daddr, *saddr;

  	struct hlist_head *chain;

  	unsigned int sequence;
  	u32 priority;

  	daddr = xfrm_flowi_daddr(fl, family);
  	saddr = xfrm_flowi_saddr(fl, family);
  	if (unlikely(!daddr || !saddr))
  		return NULL;

  	rcu_read_lock();

   retry:
  	do {
  		sequence = read_seqcount_begin(&xfrm_policy_hash_generation);
  		chain = policy_hash_direct(net, daddr, saddr, family, dir);
  	} while (read_seqcount_retry(&xfrm_policy_hash_generation, sequence));
  
  	priority = ~0U;

  	ret = NULL;

  	hlist_for_each_entry_rcu(pol, chain, bydst) {

  		err = xfrm_policy_match(pol, fl, type, family, dir);
  		if (err) {
  			if (err == -ESRCH)
  				continue;
  			else {
  				ret = ERR_PTR(err);
  				goto fail;
  			}
  		} else {

  			ret = pol;

  			priority = ret->priority;

  			break;
  		}
  	}

  	chain = &net->xfrm.policy_inexact[dir];

  	hlist_for_each_entry_rcu(pol, chain, bydst) {

  		if ((pol->priority >= priority) && ret)
  			break;

  		err = xfrm_policy_match(pol, fl, type, family, dir);
  		if (err) {
  			if (err == -ESRCH)
  				continue;
  			else {
  				ret = ERR_PTR(err);
  				goto fail;
  			}

  		} else {

  			ret = pol;
  			break;

  		}
  	}

  	if (read_seqcount_retry(&xfrm_policy_hash_generation, sequence))
  		goto retry;

  	if (ret && !xfrm_pol_hold_rcu(ret))
  		goto retry;

  fail:

  	rcu_read_unlock();

  	return ret;

  }

  static struct xfrm_policy *

  xfrm_policy_lookup(struct net *net, const struct flowi *fl, u16 family, u8 dir)

  {
  #ifdef CONFIG_XFRM_SUB_POLICY
  	struct xfrm_policy *pol;
  
  	pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_SUB, fl, family, dir);
  	if (pol != NULL)
  		return pol;
  #endif
  	return xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_MAIN, fl, family, dir);
  }

  static struct xfrm_policy *xfrm_sk_policy_lookup(const struct sock *sk, int dir,

  						 const struct flowi *fl, u16 family)

  {
  	struct xfrm_policy *pol;

  	rcu_read_lock();

   again:

  	pol = rcu_dereference(sk->sk_policy[dir]);
  	if (pol != NULL) {

  		bool match;

  		int err = 0;

  		if (pol->family != family) {
  			pol = NULL;
  			goto out;
  		}
  
  		match = xfrm_selector_match(&pol->selector, fl, family);

  		if (match) {

  			if ((sk->sk_mark & pol->mark.m) != pol->mark.v) {
  				pol = NULL;
  				goto out;
  			}

  			err = security_xfrm_policy_lookup(pol->security,

  						      fl->flowi_secid,

  						      dir);

  			if (!err) {
  				if (!xfrm_pol_hold_rcu(pol))
  					goto again;
  			} else if (err == -ESRCH) {

  				pol = NULL;

  			} else {

  				pol = ERR_PTR(err);

  			}

  		} else

  			pol = NULL;
  	}

  out:

  	rcu_read_unlock();

  	return pol;
  }
  
  static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
  {

  	struct net *net = xp_net(pol);

  	list_add(&pol->walk.all, &net->xfrm.policy_all);

  	net->xfrm.policy_count[dir]++;

  	xfrm_pol_hold(pol);
  }
  
  static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
  						int dir)
  {

  	struct net *net = xp_net(pol);

  	if (list_empty(&pol->walk.all))

  		return NULL;

  	/* Socket policies are not hashed. */
  	if (!hlist_unhashed(&pol->bydst)) {

  		hlist_del_rcu(&pol->bydst);

  		hlist_del(&pol->byidx);
  	}
  
  	list_del_init(&pol->walk.all);

  	net->xfrm.policy_count[dir]--;

  
  	return pol;

  }

  static void xfrm_sk_policy_link(struct xfrm_policy *pol, int dir)
  {
  	__xfrm_policy_link(pol, XFRM_POLICY_MAX + dir);
  }
  
  static void xfrm_sk_policy_unlink(struct xfrm_policy *pol, int dir)
  {
  	__xfrm_policy_unlink(pol, XFRM_POLICY_MAX + dir);
  }

  int xfrm_policy_delete(struct xfrm_policy *pol, int dir)

  {

  	struct net *net = xp_net(pol);

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	pol = __xfrm_policy_unlink(pol, dir);

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  	if (pol) {

  		xfrm_policy_kill(pol);

  		return 0;

  	}

  	return -ENOENT;

  }

  EXPORT_SYMBOL(xfrm_policy_delete);

  
  int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
  {

  	struct net *net = xp_net(pol);

  	struct xfrm_policy *old_pol;

  #ifdef CONFIG_XFRM_SUB_POLICY
  	if (pol && pol->type != XFRM_POLICY_TYPE_MAIN)
  		return -EINVAL;
  #endif

  	spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  	old_pol = rcu_dereference_protected(sk->sk_policy[dir],
  				lockdep_is_held(&net->xfrm.xfrm_policy_lock));

  	if (pol) {

  		pol->curlft.add_time = get_seconds();

  		pol->index = xfrm_gen_index(net, XFRM_POLICY_MAX+dir, 0);

  		xfrm_sk_policy_link(pol, dir);

  	}

  	rcu_assign_pointer(sk->sk_policy[dir], pol);

  	if (old_pol) {
  		if (pol)
  			xfrm_policy_requeue(old_pol, pol);

  		/* Unlinking succeeds always. This is the only function
  		 * allowed to delete or replace socket policy.
  		 */

  		xfrm_sk_policy_unlink(old_pol, dir);

  	}

  	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  
  	if (old_pol) {
  		xfrm_policy_kill(old_pol);
  	}
  	return 0;
  }

  static struct xfrm_policy *clone_policy(const struct xfrm_policy *old, int dir)

  {

  	struct xfrm_policy *newp = xfrm_policy_alloc(xp_net(old), GFP_ATOMIC);

  	struct net *net = xp_net(old);

  
  	if (newp) {
  		newp->selector = old->selector;

  		if (security_xfrm_policy_clone(old->security,
  					       &newp->security)) {

  			kfree(newp);
  			return NULL;  /* ENOMEM */
  		}

  		newp->lft = old->lft;
  		newp->curlft = old->curlft;

  		newp->mark = old->mark;

  		newp->action = old->action;
  		newp->flags = old->flags;
  		newp->xfrm_nr = old->xfrm_nr;
  		newp->index = old->index;

  		newp->type = old->type;

  		newp->family = old->family;

  		memcpy(newp->xfrm_vec, old->xfrm_vec,
  		       newp->xfrm_nr*sizeof(struct xfrm_tmpl));

  		spin_lock_bh(&net->xfrm.xfrm_policy_lock);

  		xfrm_sk_policy_link(newp, dir);

  		spin_unlock_bh(&net->xfrm.xfrm_policy_lock);

  		xfrm_pol_put(newp);
  	}
  	return newp;
  }

  int __xfrm_sk_clone_policy(struct sock *sk, const struct sock *osk)

  {

  	const struct xfrm_policy *p;
  	struct xfrm_policy *np;
  	int i, ret = 0;
  
  	rcu_read_lock();
  	for (i = 0; i < 2; i++) {
  		p = rcu_dereference(osk->sk_policy[i]);
  		if (p) {
  			np = clone_policy(p, i);
  			if (unlikely(!np)) {
  				ret = -ENOMEM;
  				break;
  			}
  			rcu_assign_pointer(sk->sk_policy[i], np);
  		}
  	}
  	rcu_read_unlock();
  	return ret;

  }

  static int

  xfrm_get_saddr(struct net *net, int oif, xfrm_address_t *local,

  	       xfrm_address_t *remote, unsigned short family, u32 mark)

  {
  	int err;

  	const struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);

  
  	if (unlikely(afinfo == NULL))
  		return -EINVAL;

  	err = afinfo->get_saddr(net, oif, local, remote, mark);

  	rcu_read_unlock();

  	return err;
  }

  /* Resolve list of templates for the flow, given policy. */
  
  static int

  xfrm_tmpl_resolve_one(struct xfrm_policy *policy, const struct flowi *fl,
  		      struct xfrm_state **xfrm, unsigned short family)

  {

  	struct net *net = xp_net(policy);

  	int nx;
  	int i, error;

  	xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
  	xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);

  	xfrm_address_t tmp;

  	for (nx = 0, i = 0; i < policy->xfrm_nr; i++) {

  		struct xfrm_state *x;

  		xfrm_address_t *remote = daddr;
  		xfrm_address_t *local  = saddr;

  		struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];

  		if (tmpl->mode == XFRM_MODE_TUNNEL ||
  		    tmpl->mode == XFRM_MODE_BEET) {
  			remote = &tmpl->id.daddr;
  			local = &tmpl->saddr;
  			if (xfrm_addr_any(local, tmpl->encap_family)) {
  				error = xfrm_get_saddr(net, fl->flowi_oif,
  						       &tmp, remote,
  						       tmpl->encap_family, 0);
  				if (error)
  					goto fail;
  				local = &tmp;
  			}

  		}
  
  		x = xfrm_state_find(remote, local, fl, tmpl, policy, &error, family);
  
  		if (x && x->km.state == XFRM_STATE_VALID) {
  			xfrm[nx++] = x;

  			daddr = remote;
  			saddr = local;

  			continue;
  		}
  		if (x) {
  			error = (x->km.state == XFRM_STATE_ERROR ?
  				 -EINVAL : -EAGAIN);
  			xfrm_state_put(x);

  		} else if (error == -ESRCH) {

  			error = -EAGAIN;

  		}

  
  		if (!tmpl->optional)
  			goto fail;
  	}
  	return nx;
  
  fail: