/*
 * xfrm_state.c
 *
 * Changes:
 *	Mitsuru KANDA @USAGI
 * 	Kazunori MIYAZAWA @USAGI
 * 	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
 * 		IPv6 support
 * 	YOSHIFUJI Hideaki @USAGI
 * 		Split up af-specific functions
 *	Derek Atkins <derek@ihtfp.com>
 *		Add UDP Encapsulation
 *
 */

#include <linux/workqueue.h>
#include <net/xfrm.h>
#include <linux/pfkeyv2.h>
#include <linux/ipsec.h>
#include <linux/module.h>
#include <linux/cache.h>
#include <linux/audit.h>
#include <asm/uaccess.h>
#include <linux/ktime.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>

#include "xfrm_hash.h"

/* Each xfrm_state may be linked to two tables:

   1. Hash table by (spi,daddr,ah/esp) to find SA by SPI. (input,ctl)
   2. Hash table by (daddr,family,reqid) to find what SAs exist for given
      destination/tunnel endpoint. (output)
 */

static DEFINE_SPINLOCK(xfrm_state_lock);

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

static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family);
static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo);

static inline unsigned int xfrm_dst_hash(struct net *net,
					 const xfrm_address_t *daddr,
					 const xfrm_address_t *saddr,
					 u32 reqid,
					 unsigned short family)
{
	return __xfrm_dst_hash(daddr, saddr, reqid, family, net->xfrm.state_hmask);
}

static inline unsigned int xfrm_src_hash(struct net *net,
					 const xfrm_address_t *daddr,
					 const xfrm_address_t *saddr,
					 unsigned short family)
{
	return __xfrm_src_hash(daddr, saddr, family, net->xfrm.state_hmask);
}

static inline unsigned int
xfrm_spi_hash(struct net *net, const xfrm_address_t *daddr,
	      __be32 spi, u8 proto, unsigned short family)
{
	return __xfrm_spi_hash(daddr, spi, proto, family, net->xfrm.state_hmask);
}

static void xfrm_hash_transfer(struct hlist_head *list,
			       struct hlist_head *ndsttable,
			       struct hlist_head *nsrctable,
			       struct hlist_head *nspitable,
			       unsigned int nhashmask)
{
	struct hlist_node *tmp;
	struct xfrm_state *x;

	hlist_for_each_entry_safe(x, tmp, list, bydst) {
		unsigned int h;

		h = __xfrm_dst_hash(&x->id.daddr, &x->props.saddr,
				    x->props.reqid, x->props.family,
				    nhashmask);
		hlist_add_head(&x->bydst, ndsttable+h);

		h = __xfrm_src_hash(&x->id.daddr, &x->props.saddr,
				    x->props.family,
				    nhashmask);
		hlist_add_head(&x->bysrc, nsrctable+h);

		if (x->id.spi) {
			h = __xfrm_spi_hash(&x->id.daddr, x->id.spi,
					    x->id.proto, x->props.family,
					    nhashmask);
			hlist_add_head(&x->byspi, nspitable+h);
		}
	}
}

static unsigned long xfrm_hash_new_size(unsigned int state_hmask)
{
	return ((state_hmask + 1) << 1) * sizeof(struct hlist_head);
}

static DEFINE_MUTEX(hash_resize_mutex);

static void xfrm_hash_resize(struct work_struct *work)
{
	struct net *net = container_of(work, struct net, xfrm.state_hash_work);
	struct hlist_head *ndst, *nsrc, *nspi, *odst, *osrc, *ospi;
	unsigned long nsize, osize;
	unsigned int nhashmask, ohashmask;
	int i;

	mutex_lock(&hash_resize_mutex);

	nsize = xfrm_hash_new_size(net->xfrm.state_hmask);
	ndst = xfrm_hash_alloc(nsize);
	if (!ndst)
		goto out_unlock;
	nsrc = xfrm_hash_alloc(nsize);
	if (!nsrc) {
		xfrm_hash_free(ndst, nsize);
		goto out_unlock;
	}
	nspi = xfrm_hash_alloc(nsize);
	if (!nspi) {
		xfrm_hash_free(ndst, nsize);
		xfrm_hash_free(nsrc, nsize);
		goto out_unlock;
	}

	spin_lock_bh(&xfrm_state_lock);

	nhashmask = (nsize / sizeof(struct hlist_head)) - 1U;
	for (i = net->xfrm.state_hmask; i >= 0; i--)
		xfrm_hash_transfer(net->xfrm.state_bydst+i, ndst, nsrc, nspi,
				   nhashmask);

	odst = net->xfrm.state_bydst;
	osrc = net->xfrm.state_bysrc;
	ospi = net->xfrm.state_byspi;
	ohashmask = net->xfrm.state_hmask;

	net->xfrm.state_bydst = ndst;
	net->xfrm.state_bysrc = nsrc;
	net->xfrm.state_byspi = nspi;
	net->xfrm.state_hmask = nhashmask;

	spin_unlock_bh(&xfrm_state_lock);

	osize = (ohashmask + 1) * sizeof(struct hlist_head);
	xfrm_hash_free(odst, osize);
	xfrm_hash_free(osrc, osize);
	xfrm_hash_free(ospi, osize);

out_unlock:
	mutex_unlock(&hash_resize_mutex);
}

static DEFINE_SPINLOCK(xfrm_state_afinfo_lock);
static struct xfrm_state_afinfo __rcu *xfrm_state_afinfo[NPROTO];

static DEFINE_SPINLOCK(xfrm_state_gc_lock);

int __xfrm_state_delete(struct xfrm_state *x);

int km_query(struct xfrm_state *x, struct xfrm_tmpl *t, struct xfrm_policy *pol);
void km_state_expired(struct xfrm_state *x, int hard, u32 portid);

static DEFINE_SPINLOCK(xfrm_type_lock);
int xfrm_register_type(const struct xfrm_type *type, unsigned short family)
{
	struct xfrm_state_afinfo *afinfo = xfrm_state_get_afinfo(family);
	const struct xfrm_type **typemap;
	int err = 0;

	if (unlikely(afinfo == NULL))
		return -EAFNOSUPPORT;
	typemap = afinfo->type_map;
	spin_lock_bh(&xfrm_type_lock);

	if (likely(typemap[type->proto] == NULL))
		typemap[type->proto] = type;
	else
		err = -EEXIST;
	spin_unlock_bh(&xfrm_type_lock);
	xfrm_state_put_afinfo(afinfo);
	return err;
}
EXPORT_SYMBOL(xfrm_register_type);

int xfrm_unregister_type(const struct xfrm_type *type, unsigned short family)
{
	struct xfrm_state_afinfo *afinfo = xfrm_state_get_afinfo(family);
	const struct xfrm_type **typemap;
	int err = 0;

	if (unlikely(afinfo == NULL))
		return -EAFNOSUPPORT;
	typemap = afinfo->type_map;
	spin_lock_bh(&xfrm_type_lock);

	if (unlikely(typemap[type->proto] != type))
		err = -ENOENT;
	else
		typemap[type->proto] = NULL;
	spin_unlock_bh(&xfrm_type_lock);
	xfrm_state_put_afinfo(afinfo);
	return err;
}
EXPORT_SYMBOL(xfrm_unregister_type);

static const struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
{
	struct xfrm_state_afinfo *afinfo;
	const struct xfrm_type **typemap;
	const struct xfrm_type *type;
	int modload_attempted = 0;

retry:
	afinfo = xfrm_state_get_afinfo(family);
	if (unlikely(afinfo == NULL))
		return NULL;
	typemap = afinfo->type_map;

	type = typemap[proto];
	if (unlikely(type && !try_module_get(type->owner)))
		type = NULL;
	if (!type && !modload_attempted) {
		xfrm_state_put_afinfo(afinfo);
		request_module("xfrm-type-%d-%d", family, proto);
		modload_attempted = 1;
		goto retry;
	}

	xfrm_state_put_afinfo(afinfo);
	return type;
}

static void xfrm_put_type(const struct xfrm_type *type)
{
	module_put(type->owner);
}

static DEFINE_SPINLOCK(xfrm_mode_lock);
int xfrm_register_mode(struct xfrm_mode *mode, int family)
{
	struct xfrm_state_afinfo *afinfo;
	struct xfrm_mode **modemap;
	int err;

	if (unlikely(mode->encap >= XFRM_MODE_MAX))
		return -EINVAL;

	afinfo = xfrm_state_get_afinfo(family);
	if (unlikely(afinfo == NULL))
		return -EAFNOSUPPORT;

	err = -EEXIST;
	modemap = afinfo->mode_map;
	spin_lock_bh(&xfrm_mode_lock);
	if (modemap[mode->encap])
		goto out;

	err = -ENOENT;
	if (!try_module_get(afinfo->owner))
		goto out;

	mode->afinfo = afinfo;
	modemap[mode->encap] = mode;
	err = 0;

out:
	spin_unlock_bh(&xfrm_mode_lock);
	xfrm_state_put_afinfo(afinfo);
	return err;
}
EXPORT_SYMBOL(xfrm_register_mode);

int xfrm_unregister_mode(struct xfrm_mode *mode, int family)
{
	struct xfrm_state_afinfo *afinfo;
	struct xfrm_mode **modemap;
	int err;

	if (unlikely(mode->encap >= XFRM_MODE_MAX))
		return -EINVAL;

	afinfo = xfrm_state_get_afinfo(family);
	if (unlikely(afinfo == NULL))
		return -EAFNOSUPPORT;

	err = -ENOENT;
	modemap = afinfo->mode_map;
	spin_lock_bh(&xfrm_mode_lock);
	if (likely(modemap[mode->encap] == mode)) {
		modemap[mode->encap] = NULL;
		module_put(mode->afinfo->owner);
		err = 0;
	}

	spin_unlock_bh(&xfrm_mode_lock);
	xfrm_state_put_afinfo(afinfo);
	return err;
}
EXPORT_SYMBOL(xfrm_unregister_mode);

static struct xfrm_mode *xfrm_get_mode(unsigned int encap, int family)
{
	struct xfrm_state_afinfo *afinfo;
	struct xfrm_mode *mode;
	int modload_attempted = 0;

	if (unlikely(encap >= XFRM_MODE_MAX))
		return NULL;

retry:
	afinfo = xfrm_state_get_afinfo(family);
	if (unlikely(afinfo == NULL))
		return NULL;

	mode = afinfo->mode_map[encap];
	if (unlikely(mode && !try_module_get(mode->owner)))
		mode = NULL;
	if (!mode && !modload_attempted) {
		xfrm_state_put_afinfo(afinfo);
		request_module("xfrm-mode-%d-%d", family, encap);
		modload_attempted = 1;
		goto retry;
	}

	xfrm_state_put_afinfo(afinfo);
	return mode;
}

static void xfrm_put_mode(struct xfrm_mode *mode)
{
	module_put(mode->owner);
}

static void xfrm_state_gc_destroy(struct xfrm_state *x)
{
	tasklet_hrtimer_cancel(&x->mtimer);
	del_timer_sync(&x->rtimer);
	kfree(x->aalg);
	kfree(x->ealg);
	kfree(x->calg);
	kfree(x->encap);
	kfree(x->coaddr);
	kfree(x->replay_esn);
	kfree(x->preplay_esn);
	if (x->inner_mode)
		xfrm_put_mode(x->inner_mode);
	if (x->inner_mode_iaf)
		xfrm_put_mode(x->inner_mode_iaf);
	if (x->outer_mode)
		xfrm_put_mode(x->outer_mode);
	if (x->type) {
		x->type->destructor(x);
		xfrm_put_type(x->type);
	}
	security_xfrm_state_free(x);
	kfree(x);
}

static void xfrm_state_gc_task(struct work_struct *work)
{
	struct net *net = container_of(work, struct net, xfrm.state_gc_work);
	struct xfrm_state *x;
	struct hlist_node *tmp;
	struct hlist_head gc_list;

	spin_lock_bh(&xfrm_state_gc_lock);
	hlist_move_list(&net->xfrm.state_gc_list, &gc_list);
	spin_unlock_bh(&xfrm_state_gc_lock);

	hlist_for_each_entry_safe(x, tmp, &gc_list, gclist)
		xfrm_state_gc_destroy(x);

	wake_up(&net->xfrm.km_waitq);
}

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 enum hrtimer_restart xfrm_timer_handler(struct hrtimer * me)
{
	struct tasklet_hrtimer *thr = container_of(me, struct tasklet_hrtimer, timer);
	struct xfrm_state *x = container_of(thr, struct xfrm_state, mtimer);
	struct net *net = xs_net(x);
	unsigned long now = get_seconds();
	long next = LONG_MAX;
	int warn = 0;
	int err = 0;

	spin_lock(&x->lock);
	if (x->km.state == XFRM_STATE_DEAD)
		goto out;
	if (x->km.state == XFRM_STATE_EXPIRED)
		goto expired;
	if (x->lft.hard_add_expires_seconds) {
		long tmo = x->lft.hard_add_expires_seconds +
			x->curlft.add_time - now;
		if (tmo <= 0) {
			if (x->xflags & XFRM_SOFT_EXPIRE) {
				/* enter hard expire without soft expire first?!
				 * setting a new date could trigger this.
				 * workarbound: fix x->curflt.add_time by below:
				 */
				x->curlft.add_time = now - x->saved_tmo - 1;
				tmo = x->lft.hard_add_expires_seconds - x->saved_tmo;
			} else
				goto expired;
		}
		if (tmo < next)
			next = tmo;
	}
	if (x->lft.hard_use_expires_seconds) {
		long tmo = x->lft.hard_use_expires_seconds +
			(x->curlft.use_time ? : now) - now;
		if (tmo <= 0)
			goto expired;
		if (tmo < next)
			next = tmo;
	}
	if (x->km.dying)
		goto resched;
	if (x->lft.soft_add_expires_seconds) {
		long tmo = x->lft.soft_add_expires_seconds +
			x->curlft.add_time - now;
		if (tmo <= 0) {
			warn = 1;
			x->xflags &= ~XFRM_SOFT_EXPIRE;
		} else if (tmo < next) {
			next = tmo;
			x->xflags |= XFRM_SOFT_EXPIRE;
			x->saved_tmo = tmo;
		}
	}
	if (x->lft.soft_use_expires_seconds) {
		long tmo = x->lft.soft_use_expires_seconds +
			(x->curlft.use_time ? : now) - now;
		if (tmo <= 0)
			warn = 1;
		else if (tmo < next)
			next = tmo;
	}

	x->km.dying = warn;
	if (warn)
		km_state_expired(x, 0, 0);
resched:
	if (next != LONG_MAX){
		tasklet_hrtimer_start(&x->mtimer, ktime_set(next, 0), HRTIMER_MODE_REL);
	}

	goto out;

expired:
	if (x->km.state == XFRM_STATE_ACQ && x->id.spi == 0) {
		x->km.state = XFRM_STATE_EXPIRED;
		wake_up(&net->xfrm.km_waitq);
		next = 2;
		goto resched;
	}

	err = __xfrm_state_delete(x);
	if (!err)
		km_state_expired(x, 1, 0);

	xfrm_audit_state_delete(x, err ? 0 : 1,
				audit_get_loginuid(current),
				audit_get_sessionid(current), 0);

out:
	spin_unlock(&x->lock);
	return HRTIMER_NORESTART;
}

static void xfrm_replay_timer_handler(unsigned long data);

struct xfrm_state *xfrm_state_alloc(struct net *net)
{
	struct xfrm_state *x;

	x = kzalloc(sizeof(struct xfrm_state), GFP_ATOMIC);

	if (x) {
		write_pnet(&x->xs_net, net);
		atomic_set(&x->refcnt, 1);
		atomic_set(&x->tunnel_users, 0);
		INIT_LIST_HEAD(&x->km.all);
		INIT_HLIST_NODE(&x->bydst);
		INIT_HLIST_NODE(&x->bysrc);
		INIT_HLIST_NODE(&x->byspi);
		tasklet_hrtimer_init(&x->mtimer, xfrm_timer_handler,
					CLOCK_BOOTTIME, HRTIMER_MODE_ABS);
		setup_timer(&x->rtimer, xfrm_replay_timer_handler,
				(unsigned long)x);
		x->curlft.add_time = get_seconds();
		x->lft.soft_byte_limit = XFRM_INF;
		x->lft.soft_packet_limit = XFRM_INF;
		x->lft.hard_byte_limit = XFRM_INF;
		x->lft.hard_packet_limit = XFRM_INF;
		x->replay_maxage = 0;
		x->replay_maxdiff = 0;
		x->inner_mode = NULL;
		x->inner_mode_iaf = NULL;
		spin_lock_init(&x->lock);
	}
	return x;
}
EXPORT_SYMBOL(xfrm_state_alloc);

void __xfrm_state_destroy(struct xfrm_state *x)
{
	struct net *net = xs_net(x);

	WARN_ON(x->km.state != XFRM_STATE_DEAD);

	spin_lock_bh(&xfrm_state_gc_lock);
	hlist_add_head(&x->gclist, &net->xfrm.state_gc_list);
	spin_unlock_bh(&xfrm_state_gc_lock);
	schedule_work(&net->xfrm.state_gc_work);
}
EXPORT_SYMBOL(__xfrm_state_destroy);

int __xfrm_state_delete(struct xfrm_state *x)
{
	struct net *net = xs_net(x);
	int err = -ESRCH;

	if (x->km.state != XFRM_STATE_DEAD) {
		x->km.state = XFRM_STATE_DEAD;
		spin_lock(&xfrm_state_lock);
		list_del(&x->km.all);
		hlist_del(&x->bydst);
		hlist_del(&x->bysrc);
		if (x->id.spi)
			hlist_del(&x->byspi);
		net->xfrm.state_num--;
		spin_unlock(&xfrm_state_lock);

		/* All xfrm_state objects are created by xfrm_state_alloc.
		 * The xfrm_state_alloc call gives a reference, and that
		 * is what we are dropping here.
		 */
		xfrm_state_put(x);
		err = 0;
	}

	return err;
}
EXPORT_SYMBOL(__xfrm_state_delete);

int xfrm_state_delete(struct xfrm_state *x)
{
	int err;

	spin_lock_bh(&x->lock);
	err = __xfrm_state_delete(x);
	spin_unlock_bh(&x->lock);

	return err;
}
EXPORT_SYMBOL(xfrm_state_delete);

#ifdef CONFIG_SECURITY_NETWORK_XFRM
static inline int
xfrm_state_flush_secctx_check(struct net *net, u8 proto, struct xfrm_audit *audit_info)
{
	int i, err = 0;

	for (i = 0; i <= net->xfrm.state_hmask; i++) {
		struct xfrm_state *x;

		hlist_for_each_entry(x, net->xfrm.state_bydst+i, bydst) {
			if (xfrm_id_proto_match(x->id.proto, proto) &&
			   (err = security_xfrm_state_delete(x)) != 0) {
				xfrm_audit_state_delete(x, 0,
							audit_info->loginuid,
							audit_info->sessionid,
							audit_info->secid);
				return err;
			}
		}
	}

	return err;
}
#else
static inline int
xfrm_state_flush_secctx_check(struct net *net, u8 proto, struct xfrm_audit *audit_info)
{
	return 0;
}
#endif

int xfrm_state_flush(struct net *net, u8 proto, struct xfrm_audit *audit_info)
{
	int i, err = 0, cnt = 0;

	spin_lock_bh(&xfrm_state_lock);
	err = xfrm_state_flush_secctx_check(net, proto, audit_info);
	if (err)
		goto out;

	err = -ESRCH;
	for (i = 0; i <= net->xfrm.state_hmask; i++) {
		struct xfrm_state *x;
restart:
		hlist_for_each_entry(x, net->xfrm.state_bydst+i, bydst) {
			if (!xfrm_state_kern(x) &&
			    xfrm_id_proto_match(x->id.proto, proto)) {
				xfrm_state_hold(x);
				spin_unlock_bh(&xfrm_state_lock);

				err = xfrm_state_delete(x);
				xfrm_audit_state_delete(x, err ? 0 : 1,
							audit_info->loginuid,
							audit_info->sessionid,
							audit_info->secid);
				xfrm_state_put(x);
				if (!err)
					cnt++;

				spin_lock_bh(&xfrm_state_lock);
				goto restart;
			}
		}
	}
	if (cnt)
		err = 0;

out:
	spin_unlock_bh(&xfrm_state_lock);
	wake_up(&net->xfrm.km_waitq);
	return err;
}
EXPORT_SYMBOL(xfrm_state_flush);

void xfrm_sad_getinfo(struct net *net, struct xfrmk_sadinfo *si)
{
	spin_lock_bh(&xfrm_state_lock);
	si->sadcnt = net->xfrm.state_num;
	si->sadhcnt = net->xfrm.state_hmask;
	si->sadhmcnt = xfrm_state_hashmax;
	spin_unlock_bh(&xfrm_state_lock);
}
EXPORT_SYMBOL(xfrm_sad_getinfo);

static int
xfrm_init_tempstate(struct xfrm_state *x, const struct flowi *fl,
		    const struct xfrm_tmpl *tmpl,
		    const xfrm_address_t *daddr, const xfrm_address_t *saddr,
		    unsigned short family)
{
	struct xfrm_state_afinfo *afinfo = xfrm_state_get_afinfo(family);
	if (!afinfo)
		return -1;
	afinfo->init_tempsel(&x->sel, fl);

	if (family != tmpl->encap_family) {
		xfrm_state_put_afinfo(afinfo);
		afinfo = xfrm_state_get_afinfo(tmpl->encap_family);
		if (!afinfo)
			return -1;
	}
	afinfo->init_temprop(x, tmpl, daddr, saddr);
	xfrm_state_put_afinfo(afinfo);
	return 0;
}

static struct xfrm_state *__xfrm_state_lookup(struct net *net, u32 mark,
					      const xfrm_address_t *daddr,
					      __be32 spi, u8 proto,
					      unsigned short family)
{
	unsigned int h = xfrm_spi_hash(net, daddr, spi, proto, family);
	struct xfrm_state *x;

	hlist_for_each_entry(x, net->xfrm.state_byspi+h, byspi) {
		if (x->props.family != family ||
		    x->id.spi       != spi ||
		    x->id.proto     != proto ||
		    !xfrm_addr_equal(&x->id.daddr, daddr, family))
			continue;

		if ((mark & x->mark.m) != x->mark.v)
			continue;
		xfrm_state_hold(x);
		return x;
	}

	return NULL;
}

static struct xfrm_state *__xfrm_state_lookup_byaddr(struct net *net, u32 mark,
						     const xfrm_address_t *daddr,
						     const xfrm_address_t *saddr,
						     u8 proto, unsigned short family)
{
	unsigned int h = xfrm_src_hash(net, daddr, saddr, family);
	struct xfrm_state *x;

	hlist_for_each_entry(x, net->xfrm.state_bysrc+h, bysrc) {
		if (x->props.family != family ||
		    x->id.proto     != proto ||
		    !xfrm_addr_equal(&x->id.daddr, daddr, family) ||
		    !xfrm_addr_equal(&x->props.saddr, saddr, family))
			continue;

		if ((mark & x->mark.m) != x->mark.v)
			continue;
		xfrm_state_hold(x);
		return x;
	}

	return NULL;
}

static inline struct xfrm_state *
__xfrm_state_locate(struct xfrm_state *x, int use_spi, int family)
{
	struct net *net = xs_net(x);
	u32 mark = x->mark.v & x->mark.m;

	if (use_spi)
		return __xfrm_state_lookup(net, mark, &x->id.daddr,
					   x->id.spi, x->id.proto, family);
	else
		return __xfrm_state_lookup_byaddr(net, mark,
						  &x->id.daddr,
						  &x->props.saddr,
						  x->id.proto, family);
}

static void xfrm_hash_grow_check(struct net *net, int have_hash_collision)
{
	if (have_hash_collision &&
	    (net->xfrm.state_hmask + 1) < xfrm_state_hashmax &&
	    net->xfrm.state_num > net->xfrm.state_hmask)
		schedule_work(&net->xfrm.state_hash_work);
}

static void xfrm_state_look_at(struct xfrm_policy *pol, struct xfrm_state *x,
			       const struct flowi *fl, unsigned short family,
			       struct xfrm_state **best, int *acq_in_progress,
			       int *error)
{
	/* Resolution logic:
	 * 1. There is a valid state with matching selector. Done.
	 * 2. Valid state with inappropriate selector. Skip.
	 *
	 * Entering area of "sysdeps".
	 *
	 * 3. If state is not valid, selector is temporary, it selects
	 *    only session which triggered previous resolution. Key
	 *    manager will do something to install a state with proper
	 *    selector.
	 */
	if (x->km.state == XFRM_STATE_VALID) {
		if ((x->sel.family &&
		     !xfrm_selector_match(&x->sel, fl, x->sel.family)) ||
		    !security_xfrm_state_pol_flow_match(x, pol, fl))
			return;

		if (!*best ||
		    (*best)->km.dying > x->km.dying ||
		    ((*best)->km.dying == x->km.dying &&
		     (*best)->curlft.add_time < x->curlft.add_time))
			*best = x;
	} else if (x->km.state == XFRM_STATE_ACQ) {
		*acq_in_progress = 1;
	} else if (x->km.state == XFRM_STATE_ERROR ||
		   x->km.state == XFRM_STATE_EXPIRED) {
		if (xfrm_selector_match(&x->sel, fl, x->sel.family) &&
		    security_xfrm_state_pol_flow_match(x, pol, fl))
			*error = -ESRCH;
	}
}

struct xfrm_state *
xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr,
		const struct flowi *fl, struct xfrm_tmpl *tmpl,
		struct xfrm_policy *pol, int *err,
		unsigned short family)
{
	static xfrm_address_t saddr_wildcard = { };
	struct net *net = xp_net(pol);
	unsigned int h, h_wildcard;
	struct xfrm_state *x, *x0, *to_put;
	int acquire_in_progress = 0;
	int error = 0;
	struct xfrm_state *best = NULL;
	u32 mark = pol->mark.v & pol->mark.m;
	unsigned short encap_family = tmpl->encap_family;

	to_put = NULL;

	spin_lock_bh(&xfrm_state_lock);
	h = xfrm_dst_hash(net, daddr, saddr, tmpl->reqid, encap_family);
	hlist_for_each_entry(x, net->xfrm.state_bydst+h, bydst) {
		if (x->props.family == encap_family &&
		    x->props.reqid == tmpl->reqid &&
		    (mark & x->mark.m) == x->mark.v &&
		    !(x->props.flags & XFRM_STATE_WILDRECV) &&
		    xfrm_state_addr_check(x, daddr, saddr, encap_family) &&
		    tmpl->mode == x->props.mode &&
		    tmpl->id.proto == x->id.proto &&
		    (tmpl->id.spi == x->id.spi || !tmpl->id.spi))
			xfrm_state_look_at(pol, x, fl, encap_family,
					   &best, &acquire_in_progress, &error);
	}
	if (best)
		goto found;

	h_wildcard = xfrm_dst_hash(net, daddr, &saddr_wildcard, tmpl->reqid, encap_family);
	hlist_for_each_entry(x, net->xfrm.state_bydst+h_wildcard, bydst) {
		if (x->props.family == encap_family &&
		    x->props.reqid == tmpl->reqid &&
		    (mark & x->mark.m) == x->mark.v &&
		    !(x->props.flags & XFRM_STATE_WILDRECV) &&
		    xfrm_state_addr_check(x, daddr, saddr, encap_family) &&
		    tmpl->mode == x->props.mode &&
		    tmpl->id.proto == x->id.proto &&
		    (tmpl->id.spi == x->id.spi || !tmpl->id.spi))
			xfrm_state_look_at(pol, x, fl, encap_family,
					   &best, &acquire_in_progress, &error);
	}

found:
	x = best;
	if (!x && !error && !acquire_in_progress) {
		if (tmpl->id.spi &&
		    (x0 = __xfrm_state_lookup(net, mark, daddr, tmpl->id.spi,
					      tmpl->id.proto, encap_family)) != NULL) {
			to_put = x0;
			error = -EEXIST;
			goto out;
		}
		x = xfrm_state_alloc(net);
		if (x == NULL) {
			error = -ENOMEM;
			goto out;
		}
		/* Initialize temporary state matching only
		 * to current session. */
		xfrm_init_tempstate(x, fl, tmpl, daddr, saddr, family);
		memcpy(&x->mark, &pol->mark, sizeof(x->mark));

		error = security_xfrm_state_alloc_acquire(x, pol->security, fl->flowi_secid);
		if (error) {
			x->km.state = XFRM_STATE_DEAD;
			to_put = x;
			x = NULL;
			goto out;
		}

		if (km_query(x, tmpl, pol) == 0) {
			x->km.state = XFRM_STATE_ACQ;
			list_add(&x->km.all, &net->xfrm.state_all);
			hlist_add_head(&x->bydst, net->xfrm.state_bydst+h);
			h = xfrm_src_hash(net, daddr, saddr, encap_family);
			hlist_add_head(&x->bysrc, net->xfrm.state_bysrc+h);
			if (x->id.spi) {
				h = xfrm_spi_hash(net, &x->id.daddr, x->id.spi, x->id.proto, encap_family);
				hlist_add_head(&x->byspi, net->xfrm.state_byspi+h);
			}
			x->lft.hard_add_expires_seconds = net->xfrm.sysctl_acq_expires;
			tasklet_hrtimer_start(&x->mtimer, ktime_set(net->xfrm.sysctl_acq_expires, 0), HRTIMER_MODE_REL);
			net->xfrm.state_num++;
			xfrm_hash_grow_check(net, x->bydst.next != NULL);
		} else {
			x->km.state = XFRM_STATE_DEAD;
			to_put = x;
			x = NULL;
			error = -ESRCH;
		}
	}
out:
	if (x)
		xfrm_state_hold(x);
	else
		*err = acquire_in_progress ? -EAGAIN : error;
	spin_unlock_bh(&xfrm_state_lock);
	if (to_put)
		xfrm_state_put(to_put);
	return x;
}

struct xfrm_state *
xfrm_stateonly_find(struct net *net, u32 mark,
		    xfrm_address_t *daddr, xfrm_address_t *saddr,
		    unsigned short family, u8 mode, u8 proto, u32 reqid)
{
	unsigned int h;
	struct xfrm_state *rx = NULL, *x = NULL;

	spin_lock(&xfrm_state_lock);
	h = xfrm_dst_hash(net, daddr, saddr, reqid, family);
	hlist_for_each_entry(x, net->xfrm.state_bydst+h, bydst) {
		if (x->props.family == family &&
		    x->props.reqid == reqid &&
		    (mark & x->mark.m) == x->mark.v &&
		    !(x->props.flags & XFRM_STATE_WILDRECV) &&
		    xfrm_state_addr_check(x, daddr, saddr, family) &&
		    mode == x->props.mode &&
		    proto == x->id.proto &&
		    x->km.state == XFRM_STATE_VALID) {
			rx = x;
			break;
		}
	}

	if (rx)
		xfrm_state_hold(rx);
	spin_unlock(&xfrm_state_lock);


	return rx;
}
EXPORT_SYMBOL(xfrm_stateonly_find);

static void __xfrm_state_insert(struct xfrm_state *x)
{
	struct net *net = xs_net(x);
	unsigned int h;

	list_add(&x->km.all, &net->xfrm.state_all);

	h = xfrm_dst_hash(net, &x->id.daddr, &x->props.saddr,
			  x->props.reqid, x->props.family);
	hlist_add_head(&x->bydst, net->xfrm.state_bydst+h);

	h = xfrm_src_hash(net, &x->id.daddr, &x->props.saddr, x->props.family);
	hlist_add_head(&x->bysrc, net->xfrm.state_bysrc+h);

	if (x->id.spi) {
		h = xfrm_spi_hash(net, &x->id.daddr, x->id.spi, x->id.proto,
				  x->props.family);

		hlist_add_head(&x->byspi, net->xfrm.state_byspi+h);
	}

	tasklet_hrtimer_start(&x->mtimer, ktime_set(1, 0), HRTIMER_MODE_REL);
	if (x->replay_maxage)
		mod_timer(&x->rtimer, jiffies + x->replay_maxage);

	wake_up(&net->xfrm.km_waitq);

	net->xfrm.state_num++;

	xfrm_hash_grow_check(net, x->bydst.next != NULL);
}

/* xfrm_state_lock is held */
static void __xfrm_state_bump_genids(struct xfrm_state *xnew)
{
	struct net *net = xs_net(xnew);
	unsigned short family = xnew->props.family;
	u32 reqid = xnew->props.reqid;
	struct xfrm_state *x;
	unsigned int h;
	u32 mark = xnew->mark.v & xnew->mark.m;

	h = xfrm_dst_hash(net, &xnew->id.daddr, &xnew->props.saddr, reqid, family);
	hlist_for_each_entry(x, net->xfrm.state_bydst+h, bydst) {
		if (x->props.family	== family &&
		    x->props.reqid	== reqid &&
		    (mark & x->mark.m) == x->mark.v &&
		    xfrm_addr_equal(&x->id.daddr, &xnew->id.daddr, family) &&
		    xfrm_addr_equal(&x->props.saddr, &xnew->props.saddr, family))
			x->genid++;
	}
}

void xfrm_state_insert(struct xfrm_state *x)
{
	spin_lock_bh(&xfrm_state_lock);
	__xfrm_state_bump_genids(x);
	__xfrm_state_insert(x);
	spin_unlock_bh(&xfrm_state_lock);
}
EXPORT_SYMBOL(xfrm_state_insert);

/* xfrm_state_lock is held */
static struct xfrm_state *__find_acq_core(struct net *net,
					  const struct xfrm_mark *m,
					  unsigned short family, u8 mode,
					  u32 reqid, u8 proto,
					  const xfrm_address_t *daddr,
					  const xfrm_address_t *saddr,
					  int create)
{
	unsigned int h = xfrm_dst_hash(net, daddr, saddr, reqid, family);
	struct xfrm_state *x;
	u32 mark = m->v & m->m;

	hlist_for_each_entry(x, net->xfrm.state_bydst+h, bydst) {
		if (x->props.reqid  != reqid ||
		    x->props.mode   != mode ||
		    x->props.family != family ||
		    x->km.state     != XFRM_STATE_ACQ ||
		    x->id.spi       != 0 ||
		    x->id.proto	    != proto ||
		    (mark & x->mark.m) != x->mark.v ||
		    !xfrm_addr_equal(&x->id.daddr, daddr, family) ||
		    !xfrm_addr_equal(&x->props.saddr, saddr, family))
			continue;

		xfrm_state_hold(x);
		return x;
	}

	if (!create)
		return NULL;

	x = xfrm_state_alloc(net);
	if (likely(x)) {
		switch (family) {
		case AF_INET:
			x->sel.daddr.a4 = daddr->a4;
			x->sel.saddr.a4 = saddr->a4;
			x->sel.prefixlen_d = 32;
			x->sel.prefixlen_s = 32;
			x->props.saddr.a4 = saddr->a4;
			x->id.daddr.a4 = daddr->a4;
			break;

		case AF_INET6:
			*(struct in6_addr *)x->sel.daddr.a6 = *(struct in6_addr *)daddr;
			*(struct in6_addr *)x->sel.saddr.a6 = *(struct in6_addr *)saddr;
			x->sel.prefixlen_d = 128;
			x->sel.prefixlen_s = 128;
			*(struct in6_addr *)x->props.saddr.a6 = *(struct in6_addr *)saddr;
			*(struct in6_addr *)x->id.daddr.a6 = *(struct in6_addr *)daddr;
			break;
		}

		x->km.state = XFRM_STATE_ACQ;
		x->id.proto = proto;
		x->props.family = family;
		x->props.mode = mode;
		x->props.reqid = reqid;
		x->mark.v = m->v;
		x->mark.m = m->m;
		x->lft.hard_add_expires_seconds = net->xfrm.sysctl_acq_expires;
		xfrm_state_hold(x);
		tasklet_hrtimer_start(&x->mtimer, ktime_set(net->xfrm.sysctl_acq_expires, 0), HRTIMER_MODE_REL);
		list_add(&x->km.all, &net->xfrm.state_all);
		hlist_add_head(&x->bydst, net->xfrm.state_bydst+h);
		h = xfrm_src_hash(net, daddr, saddr, family);
		hlist_add_head(&x->bysrc, net->xfrm.state_bysrc+h);

		net->xfrm.state_num++;

		xfrm_hash_grow_check(net, x->bydst.next != NULL);
	}

	return x;
}

static struct xfrm_state *__xfrm_find_acq_byseq(struct net *net, u32 mark, u32 seq);

int xfrm_state_add(struct xfrm_state *x)
{
	struct net *net = xs_net(x);
	struct xfrm_state *x1, *to_put;
	int family;
	int err;
	u32 mark = x->mark.v & x->mark.m;
	int use_spi = xfrm_id_proto_match(x->id.proto, IPSEC_PROTO_ANY);

	family = x->props.family;

	to_put = NULL;

	spin_lock_bh(&xfrm_state_lock);

	x1 = __xfrm_state_locate(x, use_spi, family);
	if (x1) {
		to_put = x1;
		x1 = NULL;
		err = -EEXIST;
		goto out;
	}

	if (use_spi && x->km.seq) {
		x1 = __xfrm_find_acq_byseq(net, mark, x->km.seq);
		if (x1 && ((x1->id.proto != x->id.proto) ||
		    !xfrm_addr_equal(&x1->id.daddr, &x->id.daddr, family))) {
			to_put = x1;
			x1 = NULL;
		}
	}

	if (use_spi && !x1)
		x1 = __find_acq_core(net, &x->mark, family, x->props.mode,
				     x->props.reqid, x->id.proto,
				     &x->id.daddr, &x->props.saddr, 0);

	__xfrm_state_bump_genids(x);
	__xfrm_state_insert(x);
	err = 0;

out:
	spin_unlock_bh(&xfrm_state_lock);

	if (x1) {
		xfrm_state_delete(x1);
		xfrm_state_put(x1);
	}

	if (to_put)
		xfrm_state_put(to_put);

	return err;
}
EXPORT_SYMBOL(xfrm_state_add);

#ifdef CONFIG_XFRM_MIGRATE
static struct xfrm_state *xfrm_state_clone(struct xfrm_state *orig, int *errp)
{
	struct net *net = xs_net(orig);
	int err = -ENOMEM;
	struct xfrm_state *x = xfrm_state_alloc(net);
	if (!x)
		goto out;

	memcpy(&x->id, &orig->id, sizeof(x->id));
	memcpy(&x->sel, &orig->sel, sizeof(x->sel));
	memcpy(&x->lft, &orig->lft, sizeof(x->lft));
	x->props.mode = orig->props.mode;
	x->props.replay_window = orig->props.replay_window;
	x->props.reqid = orig->props.reqid;
	x->props.family = orig->props.family;
	x->props.saddr = orig->props.saddr;

	if (orig->aalg) {
		x->aalg = xfrm_algo_auth_clone(orig->aalg);
		if (!x->aalg)
			goto error;
	}
	x->props.aalgo = orig->props.aalgo;

	if (orig->ealg) {
		x->ealg = xfrm_algo_clone(orig->ealg);
		if (!x->ealg)
			goto error;
	}
	x->props.ealgo = orig->props.ealgo;

	if (orig->calg) {
		x->calg = xfrm_algo_clone(orig->calg);
		if (!x->calg)
			goto error;
	}
	x->props.calgo = orig->props.calgo;

	if (orig->encap) {
		x->encap = kmemdup(orig->encap, sizeof(*x->encap), GFP_KERNEL);
		if (!x->encap)
			goto error;
	}

	if (orig->coaddr) {
		x->coaddr = kmemdup(orig->coaddr, sizeof(*x->coaddr),
				    GFP_KERNEL);
		if (!x->coaddr)
			goto error;
	}

	if (orig->replay_esn) {
		err = xfrm_replay_clone(x, orig);
		if (err)
			goto error;
	}

	memcpy(&x->mark, &orig->mark, sizeof(x->mark));

	err = xfrm_init_state(x);
	if (err)
		goto error;

	x->props.flags = orig->props.flags;
	x->props.extra_flags = orig->props.extra_flags;

	x->curlft.add_time = orig->curlft.add_time;
	x->km.state = orig->km.state;
	x->km.seq = orig->km.seq;

	return x;

 error:
	xfrm_state_put(x);
out:
	if (errp)
		*errp = err;
	return NULL;
}

/* xfrm_state_lock is held */
struct xfrm_state * xfrm_migrate_state_find(struct xfrm_migrate *m)
{
	unsigned int h;
	struct xfrm_state *x;

	if (m->reqid) {
		h = xfrm_dst_hash(&init_net, &m->old_daddr, &m->old_saddr,
				  m->reqid, m->old_family);
		hlist_for_each_entry(x, init_net.xfrm.state_bydst+h, bydst) {
			if (x->props.mode != m->mode ||
			    x->id.proto != m->proto)
				continue;
			if (m->reqid && x->props.reqid != m->reqid)
				continue;
			if (!xfrm_addr_equal(&x->id.daddr, &m->old_daddr,
					     m->old_family) ||
			    !xfrm_addr_equal(&x->props.saddr, &m->old_saddr,
					     m->old_family))
				continue;
			xfrm_state_hold(x);
			return x;
		}
	} else {
		h = xfrm_src_hash(&init_net, &m->old_daddr, &m->old_saddr,
				  m->old_family);
		hlist_for_each_entry(x, init_net.xfrm.state_bysrc+h, bysrc) {
			if (x->props.mode != m->mode ||
			    x->id.proto != m->proto)
				continue;
			if (!xfrm_addr_equal(&x->id.daddr, &m->old_daddr,
					     m->old_family) ||
			    !xfrm_addr_equal(&x->props.saddr, &m->old_saddr,
					     m->old_family))
				continue;
			xfrm_state_hold(x);
			return x;
		}
	}

	return NULL;
}
EXPORT_SYMBOL(xfrm_migrate_state_find);

struct xfrm_state * xfrm_state_migrate(struct xfrm_state *x,
				       struct xfrm_migrate *m)
{
	struct xfrm_state *xc;
	int err;

	xc = xfrm_state_clone(x, &err);
	if (!xc)
		return NULL;

	memcpy(&xc->id.daddr, &m->new_daddr, sizeof(xc->id.daddr));
	memcpy(&xc->props.saddr, &m->new_saddr, sizeof(xc->props.saddr));

	/* add state */
	if (xfrm_addr_equal(&x->id.daddr, &m->new_daddr, m->new_family)) {
		/* a care is needed when the destination address of the
		   state is to be updated as it is a part of triplet */
		xfrm_state_insert(xc);
	} else {
		if ((err = xfrm_state_add(xc)) < 0)
			goto error;
	}

	return xc;
error:
	xfrm_state_put(xc);
	return NULL;
}
EXPORT_SYMBOL(xfrm_state_migrate);
#endif

int xfrm_state_update(struct xfrm_state *x)
{
	struct xfrm_state *x1, *to_put;
	int err;
	int use_spi = xfrm_id_proto_match(x->id.proto, IPSEC_PROTO_ANY);

	to_put = NULL;

	spin_lock_bh(&xfrm_state_lock);
	x1 = __xfrm_state_locate(x, use_spi, x->props.family);

	err = -ESRCH;
	if (!x1)
		goto out;

	if (xfrm_state_kern(x1)) {
		to_put = x1;
		err = -EEXIST;
		goto out;
	}

	if (x1->km.state == XFRM_STATE_ACQ) {
		__xfrm_state_insert(x);
		x = NULL;
	}
	err = 0;

out:
	spin_unlock_bh(&xfrm_state_lock);

	if (to_put)
		xfrm_state_put(to_put);

	if (err)
		return err;

	if (!x) {
		xfrm_state_delete(x1);
		xfrm_state_put(x1);
		return 0;
	}

	err = -EINVAL;
	spin_lock_bh(&x1->lock);
	if (likely(x1->km.state == XFRM_STATE_VALID)) {
		if (x->encap && x1->encap)
			memcpy(x1->encap, x->encap, sizeof(*x1->encap));
		if (x->coaddr && x1->coaddr) {
			memcpy(x1->coaddr, x->coaddr, sizeof(*x1->coaddr));
		}
		if (!use_spi && memcmp(&x1->sel, &x->sel, sizeof(x1->sel)))
			memcpy(&x1->sel, &x->sel, sizeof(x1->sel));
		memcpy(&x1->lft, &x->lft, sizeof(x1->lft));
		x1->km.dying = 0;

		tasklet_hrtimer_start(&x1->mtimer, ktime_set(1, 0), HRTIMER_MODE_REL);
		if (x1->curlft.use_time)
			xfrm_state_check_expire(x1);

		err = 0;
		x->km.state = XFRM_STATE_DEAD;
		__xfrm_state_put(x);
	}
	spin_unlock_bh(&x1->lock);

	xfrm_state_put(x1);

	return err;
}
EXPORT_SYMBOL(xfrm_state_update);

int xfrm_state_check_expire(struct xfrm_state *x)
{
	if (!x->curlft.use_time)
		x->curlft.use_time = get_seconds();

	if (x->curlft.bytes >= x->lft.hard_byte_limit ||
	    x->curlft.packets >= x->lft.hard_packet_limit) {
		x->km.state = XFRM_STATE_EXPIRED;
		tasklet_hrtimer_start(&x->mtimer, ktime_set(0,0), HRTIMER_MODE_REL);
		return -EINVAL;
	}

	if (!x->km.dying &&
	    (x->curlft.bytes >= x->lft.soft_byte_limit ||
	     x->curlft.packets >= x->lft.soft_packet_limit)) {
		x->km.dying = 1;
		km_state_expired(x, 0, 0);
	}
	return 0;
}
EXPORT_SYMBOL(xfrm_state_check_expire);

struct xfrm_state *
xfrm_state_lookup(struct net *net, u32 mark, const xfrm_address_t *daddr, __be32 spi,
		  u8 proto, unsigned short family)
{
	struct xfrm_state *x;

	spin_lock_bh(&xfrm_state_lock);
	x = __xfrm_state_lookup(net, mark, daddr, spi, proto, family);
	spin_unlock_bh(&xfrm_state_lock);
	return x;
}
EXPORT_SYMBOL(xfrm_state_lookup);

struct xfrm_state *
xfrm_state_lookup_byaddr(struct net *net, u32 mark,
			 const xfrm_address_t *daddr, const xfrm_address_t *saddr,
			 u8 proto, unsigned short family)
{
	struct xfrm_state *x;

	spin_lock_bh(&xfrm_state_lock);
	x = __xfrm_state_lookup_byaddr(net, mark, daddr, saddr, proto, family);
	spin_unlock_bh(&xfrm_state_lock);
	return x;
}
EXPORT_SYMBOL(xfrm_state_lookup_byaddr);

struct xfrm_state *
xfrm_find_acq(struct net *net, const struct xfrm_mark *mark, u8 mode, u32 reqid,
	      u8 proto, const xfrm_address_t *daddr,
	      const xfrm_address_t *saddr, int create, unsigned short family)
{
	struct xfrm_state *x;

	spin_lock_bh(&xfrm_state_lock);
	x = __find_acq_core(net, mark, family, mode, reqid, proto, daddr, saddr, create);
	spin_unlock_bh(&xfrm_state_lock);

	return x;
}
EXPORT_SYMBOL(xfrm_find_acq);

#ifdef CONFIG_XFRM_SUB_POLICY
int
xfrm_tmpl_sort(struct xfrm_tmpl **dst, struct xfrm_tmpl **src, int n,
	       unsigned short family)
{
	int err = 0;
	struct xfrm_state_afinfo *afinfo = xfrm_state_get_afinfo(family);
	if (!afinfo)
		return -EAFNOSUPPORT;

	spin_lock_bh(&xfrm_state_lock);
	if (afinfo->tmpl_sort)
		err = afinfo->tmpl_sort(dst, src, n);
	spin_unlock_bh(&xfrm_state_lock);
	xfrm_state_put_afinfo(afinfo);
	return err;
}
EXPORT_SYMBOL(xfrm_tmpl_sort);

int
xfrm_state_sort(struct xfrm_state **dst, struct xfrm_state **src, int n,
		unsigned short family)
{
	int err = 0;
	struct xfrm_state_afinfo *afinfo = xfrm_state_get_afinfo(family);
	if (!afinfo)
		return -EAFNOSUPPORT;

	spin_lock_bh(&xfrm_state_lock);
	if (afinfo->state_sort)
		err = afinfo->state_sort(dst, src, n);
	spin_unlock_bh(&xfrm_state_lock);
	xfrm_state_put_afinfo(afinfo);
	return err;
}
EXPORT_SYMBOL(xfrm_state_sort);
#endif

/* Silly enough, but I'm lazy to build resolution list */

static struct xfrm_state *__xfrm_find_acq_byseq(struct net *net, u32 mark, u32 seq)
{
	int i;

	for (i = 0; i <= net->xfrm.state_hmask; i++) {
		struct xfrm_state *x;

		hlist_for_each_entry(x, net->xfrm.state_bydst+i, bydst) {
			if (x->km.seq == seq &&
			    (mark & x->mark.m) == x->mark.v &&
			    x->km.state == XFRM_STATE_ACQ) {
				xfrm_state_hold(x);
				return x;
			}
		}
	}
	return NULL;
}

struct xfrm_state *xfrm_find_acq_byseq(struct net *net, u32 mark, u32 seq)
{
	struct xfrm_state *x;

	spin_lock_bh(&xfrm_state_lock);
	x = __xfrm_find_acq_byseq(net, mark, seq);
	spin_unlock_bh(&xfrm_state_lock);
	return x;
}
EXPORT_SYMBOL(xfrm_find_acq_byseq);

u32 xfrm_get_acqseq(void)
{
	u32 res;
	static atomic_t acqseq;

	do {
		res = atomic_inc_return(&acqseq);
	} while (!res);

	return res;
}
EXPORT_SYMBOL(xfrm_get_acqseq);

int xfrm_alloc_spi(struct xfrm_state *x, u32 low, u32 high)
{
	struct net *net = xs_net(x);
	unsigned int h;
	struct xfrm_state *x0;
	int err = -ENOENT;
	__be32 minspi = htonl(low);
	__be32 maxspi = htonl(high);
	u32 mark = x->mark.v & x->mark.m;

	spin_lock_bh(&x->lock);
	if (x->km.state == XFRM_STATE_DEAD)
		goto unlock;

	err = 0;
	if (x->id.spi)
		goto unlock;

	err = -ENOENT;

	if (minspi == maxspi) {
		x0 = xfrm_state_lookup(net, mark, &x->id.daddr, minspi, x->id.proto, x->props.family);
		if (x0) {
			xfrm_state_put(x0);
			goto unlock;
		}
		x->id.spi = minspi;
	} else {
		u32 spi = 0;
		for (h=0; h<high-low+1; h++) {
			spi = low + net_random()%(high-low+1);
			x0 = xfrm_state_lookup(net, mark, &x->id.daddr, htonl(spi), x->id.proto, x->props.family);
			if (x0 == NULL) {
				x->id.spi = htonl(spi);
				break;
			}
			xfrm_state_put(x0);
		}
	}
	if (x->id.spi) {
		spin_lock_bh(&xfrm_state_lock);
		h = xfrm_spi_hash(net, &x->id.daddr, x->id.spi, x->id.proto, x->props.family);
		hlist_add_head(&x->byspi, net->xfrm.state_byspi+h);
		spin_unlock_bh(&xfrm_state_lock);

		err = 0;
	}

unlock:
	spin_unlock_bh(&x->lock);

	return err;
}
EXPORT_SYMBOL(xfrm_alloc_spi);

int xfrm_state_walk(struct net *net, struct xfrm_state_walk *walk,
		    int (*func)(struct xfrm_state *, int, void*),
		    void *data)
{
	struct xfrm_state *state;
	struct xfrm_state_walk *x;
	int err = 0;

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

	spin_lock_bh(&xfrm_state_lock);
	if (list_empty(&walk->all))
		x = list_first_entry(&net->xfrm.state_all, struct xfrm_state_walk, all);
	else
		x = list_entry(&walk->all, struct xfrm_state_walk, all);
	list_for_each_entry_from(x, &net->xfrm.state_all, all) {
		if (x->state == XFRM_STATE_DEAD)
			continue;
		state = container_of(x, struct xfrm_state, km);
		if (!xfrm_id_proto_match(state->id.proto, walk->proto))
			continue;
		err = func(state, walk->seq, data);
		if (err) {
			list_move_tail(&walk->all, &x->all);
			goto out;
		}
		walk->seq++;
	}
	if (walk->seq == 0) {
		err = -ENOENT;
		goto out;
	}
	list_del_init(&walk->all);
out:
	spin_unlock_bh(&xfrm_state_lock);
	return err;
}
EXPORT_SYMBOL(xfrm_state_walk);

void xfrm_state_walk_init(struct xfrm_state_walk *walk, u8 proto)
{
	INIT_LIST_HEAD(&walk->all);
	walk->proto = proto;
	walk->state = XFRM_STATE_DEAD;
	walk->seq = 0;
}
EXPORT_SYMBOL(xfrm_state_walk_init);

void xfrm_state_walk_done(struct xfrm_state_walk *walk)
{
	if (list_empty(&walk->all))
		return;

	spin_lock_bh(&xfrm_state_lock);
	list_del(&walk->all);
	spin_unlock_bh(&xfrm_state_lock);
}
EXPORT_SYMBOL(xfrm_state_walk_done);

static void xfrm_replay_timer_handler(unsigned long data)
{
	struct xfrm_state *x = (struct xfrm_state*)data;

	spin_lock(&x->lock);

	if (x->km.state == XFRM_STATE_VALID) {
		if (xfrm_aevent_is_on(xs_net(x)))
			x->repl->notify(x, XFRM_REPLAY_TIMEOUT);
		else
			x->xflags |= XFRM_TIME_DEFER;
	}

	spin_unlock(&x->lock);
}

static LIST_HEAD(xfrm_km_list);

void km_policy_notify(struct xfrm_policy *xp, int dir, const struct km_event *c)
{
	struct xfrm_mgr *km;

	rcu_read_lock();
	list_for_each_entry_rcu(km, &xfrm_km_list, list)
		if (km->notify_policy)
			km->notify_policy(xp, dir, c);
	rcu_read_unlock();
}

void km_state_notify(struct xfrm_state *x, const struct km_event *c)
{
	struct xfrm_mgr *km;
	rcu_read_lock();
	list_for_each_entry_rcu(km, &xfrm_km_list, list)
		if (km->notify)
			km->notify(x, c);
	rcu_read_unlock();
}

EXPORT_SYMBOL(km_policy_notify);
EXPORT_SYMBOL(km_state_notify);

void km_state_expired(struct xfrm_state *x, int hard, u32 portid)
{
	struct net *net = xs_net(x);
	struct km_event c;

	c.data.hard = hard;
	c.portid = portid;
	c.event = XFRM_MSG_EXPIRE;
	km_state_notify(x, &c);

	if (hard)
		wake_up(&net->xfrm.km_waitq);
}

EXPORT_SYMBOL(km_state_expired);
/*
 * We send to all registered managers regardless of failure
 * We are happy with one success
*/
int km_query(struct xfrm_state *x, struct xfrm_tmpl *t, struct xfrm_policy *pol)
{
	int err = -EINVAL, acqret;
	struct xfrm_mgr *km;

	rcu_read_lock();
	list_for_each_entry_rcu(km, &xfrm_km_list, list) {
		acqret = km->acquire(x, t, pol);
		if (!acqret)
			err = acqret;
	}
	rcu_read_unlock();
	return err;
}
EXPORT_SYMBOL(km_query);

int km_new_mapping(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport)
{
	int err = -EINVAL;
	struct xfrm_mgr *km;

	rcu_read_lock();
	list_for_each_entry_rcu(km, &xfrm_km_list, list) {
		if (km->new_mapping)
			err = km->new_mapping(x, ipaddr, sport);
		if (!err)
			break;
	}
	rcu_read_unlock();
	return err;
}
EXPORT_SYMBOL(km_new_mapping);

void km_policy_expired(struct xfrm_policy *pol, int dir, int hard, u32 portid)
{
	struct net *net = xp_net(pol);
	struct km_event c;

	c.data.hard = hard;
	c.portid = portid;
	c.event = XFRM_MSG_POLEXPIRE;
	km_policy_notify(pol, dir, &c);

	if (hard)
		wake_up(&net->xfrm.km_waitq);
}
EXPORT_SYMBOL(km_policy_expired);

#ifdef CONFIG_XFRM_MIGRATE
int km_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
	       const struct xfrm_migrate *m, int num_migrate,
	       const struct xfrm_kmaddress *k)
{
	int err = -EINVAL;
	int ret;
	struct xfrm_mgr *km;

	rcu_read_lock();
	list_for_each_entry_rcu(km, &xfrm_km_list, list) {
		if (km->migrate) {
			ret = km->migrate(sel, dir, type, m, num_migrate, k);
			if (!ret)
				err = ret;
		}
	}
	rcu_read_unlock();
	return err;
}
EXPORT_SYMBOL(km_migrate);
#endif

int km_report(struct net *net, u8 proto, struct xfrm_selector *sel, xfrm_address_t *addr)
{
	int err = -EINVAL;
	int ret;
	struct xfrm_mgr *km;

	rcu_read_lock();
	list_for_each_entry_rcu(km, &xfrm_km_list, list) {
		if (km->report) {
			ret = km->report(net, proto, sel, addr);
			if (!ret)
				err = ret;
		}
	}
	rcu_read_unlock();
	return err;
}
EXPORT_SYMBOL(km_report);

int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optval, int optlen)
{
	int err;
	u8 *data;
	struct xfrm_mgr *km;
	struct xfrm_policy *pol = NULL;

	if (optlen <= 0 || optlen > PAGE_SIZE)
		return -EMSGSIZE;

	data = kmalloc(optlen, GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	err = -EFAULT;
	if (copy_from_user(data, optval, optlen))
		goto out;

	err = -EINVAL;
	rcu_read_lock();
	list_for_each_entry_rcu(km, &xfrm_km_list, list) {
		pol = km->compile_policy(sk, optname, data,
					 optlen, &err);
		if (err >= 0)
			break;
	}
	rcu_read_unlock();

	if (err >= 0) {
		xfrm_sk_policy_insert(sk, err, pol);
		xfrm_pol_put(pol);
		err = 0;
	}

out:
	kfree(data);
	return err;
}
EXPORT_SYMBOL(xfrm_user_policy);

static DEFINE_SPINLOCK(xfrm_km_lock);

int xfrm_register_km(struct xfrm_mgr *km)
{
	spin_lock_bh(&xfrm_km_lock);
	list_add_tail_rcu(&km->list, &xfrm_km_list);
	spin_unlock_bh(&xfrm_km_lock);
	return 0;
}
EXPORT_SYMBOL(xfrm_register_km);

int xfrm_unregister_km(struct xfrm_mgr *km)
{
	spin_lock_bh(&xfrm_km_lock);
	list_del_rcu(&km->list);
	spin_unlock_bh(&xfrm_km_lock);
	synchronize_rcu();
	return 0;
}
EXPORT_SYMBOL(xfrm_unregister_km);

int xfrm_state_register_afinfo(struct xfrm_state_afinfo *afinfo)
{
	int err = 0;
	if (unlikely(afinfo == NULL))
		return -EINVAL;
	if (unlikely(afinfo->family >= NPROTO))
		return -EAFNOSUPPORT;
	spin_lock_bh(&xfrm_state_afinfo_lock);
	if (unlikely(xfrm_state_afinfo[afinfo->family] != NULL))
		err = -ENOBUFS;
	else
		rcu_assign_pointer(xfrm_state_afinfo[afinfo->family], afinfo);
	spin_unlock_bh(&xfrm_state_afinfo_lock);
	return err;
}
EXPORT_SYMBOL(xfrm_state_register_afinfo);

int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo)
{
	int err = 0;
	if (unlikely(afinfo == NULL))
		return -EINVAL;
	if (unlikely(afinfo->family >= NPROTO))
		return -EAFNOSUPPORT;
	spin_lock_bh(&xfrm_state_afinfo_lock);
	if (likely(xfrm_state_afinfo[afinfo->family] != NULL)) {
		if (unlikely(xfrm_state_afinfo[afinfo->family] != afinfo))
			err = -EINVAL;
		else
			RCU_INIT_POINTER(xfrm_state_afinfo[afinfo->family], NULL);
	}
	spin_unlock_bh(&xfrm_state_afinfo_lock);
	synchronize_rcu();
	return err;
}
EXPORT_SYMBOL(xfrm_state_unregister_afinfo);

static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
{
	struct xfrm_state_afinfo *afinfo;
	if (unlikely(family >= NPROTO))
		return NULL;
	rcu_read_lock();
	afinfo = rcu_dereference(xfrm_state_afinfo[family]);
	if (unlikely(!afinfo))
		rcu_read_unlock();
	return afinfo;
}

static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
{
	rcu_read_unlock();
}

/* Temporarily located here until net/xfrm/xfrm_tunnel.c is created */
void xfrm_state_delete_tunnel(struct xfrm_state *x)
{
	if (x->tunnel) {
		struct xfrm_state *t = x->tunnel;

		if (atomic_read(&t->tunnel_users) == 2)
			xfrm_state_delete(t);
		atomic_dec(&t->tunnel_users);
		xfrm_state_put(t);
		x->tunnel = NULL;
	}
}
EXPORT_SYMBOL(xfrm_state_delete_tunnel);

int xfrm_state_mtu(struct xfrm_state *x, int mtu)
{
	int res;

	spin_lock_bh(&x->lock);
	if (x->km.state == XFRM_STATE_VALID &&
	    x->type && x->type->get_mtu)
		res = x->type->get_mtu(x, mtu);
	else
		res = mtu - x->props.header_len;
	spin_unlock_bh(&x->lock);
	return res;
}

int __xfrm_init_state(struct xfrm_state *x, bool init_replay)
{
	struct xfrm_state_afinfo *afinfo;
	struct xfrm_mode *inner_mode;
	int family = x->props.family;
	int err;

	err = -EAFNOSUPPORT;
	afinfo = xfrm_state_get_afinfo(family);
	if (!afinfo)
		goto error;

	err = 0;
	if (afinfo->init_flags)
		err = afinfo->init_flags(x);

	xfrm_state_put_afinfo(afinfo);

	if (err)
		goto error;

	err = -EPROTONOSUPPORT;

	if (x->sel.family != AF_UNSPEC) {
		inner_mode = xfrm_get_mode(x->props.mode, x->sel.family);
		if (inner_mode == NULL)
			goto error;

		if (!(inner_mode->flags & XFRM_MODE_FLAG_TUNNEL) &&
		    family != x->sel.family) {
			xfrm_put_mode(inner_mode);
			goto error;
		}

		x->inner_mode = inner_mode;
	} else {
		struct xfrm_mode *inner_mode_iaf;
		int iafamily = AF_INET;

		inner_mode = xfrm_get_mode(x->props.mode, x->props.family);
		if (inner_mode == NULL)
			goto error;

		if (!(inner_mode->flags & XFRM_MODE_FLAG_TUNNEL)) {
			xfrm_put_mode(inner_mode);
			goto error;
		}
		x->inner_mode = inner_mode;

		if (x->props.family == AF_INET)
			iafamily = AF_INET6;

		inner_mode_iaf = xfrm_get_mode(x->props.mode, iafamily);
		if (inner_mode_iaf) {
			if (inner_mode_iaf->flags & XFRM_MODE_FLAG_TUNNEL)
				x->inner_mode_iaf = inner_mode_iaf;
			else
				xfrm_put_mode(inner_mode_iaf);
		}
	}

	x->type = xfrm_get_type(x->id.proto, family);
	if (x->type == NULL)
		goto error;

	err = x->type->init_state(x);
	if (err)
		goto error;

	x->outer_mode = xfrm_get_mode(x->props.mode, family);
	if (x->outer_mode == NULL) {
		err = -EPROTONOSUPPORT;
		goto error;
	}

	if (init_replay) {
		err = xfrm_init_replay(x);
		if (err)
			goto error;
	}

	x->km.state = XFRM_STATE_VALID;

error:
	return err;
}

EXPORT_SYMBOL(__xfrm_init_state);

int xfrm_init_state(struct xfrm_state *x)
{
	return __xfrm_init_state(x, true);
}

EXPORT_SYMBOL(xfrm_init_state);

int __net_init xfrm_state_init(struct net *net)
{
	unsigned int sz;

	INIT_LIST_HEAD(&net->xfrm.state_all);

	sz = sizeof(struct hlist_head) * 8;

	net->xfrm.state_bydst = xfrm_hash_alloc(sz);
	if (!net->xfrm.state_bydst)
		goto out_bydst;
	net->xfrm.state_bysrc = xfrm_hash_alloc(sz);
	if (!net->xfrm.state_bysrc)
		goto out_bysrc;
	net->xfrm.state_byspi = xfrm_hash_alloc(sz);
	if (!net->xfrm.state_byspi)
		goto out_byspi;
	net->xfrm.state_hmask = ((sz / sizeof(struct hlist_head)) - 1);

	net->xfrm.state_num = 0;
	INIT_WORK(&net->xfrm.state_hash_work, xfrm_hash_resize);
	INIT_HLIST_HEAD(&net->xfrm.state_gc_list);
	INIT_WORK(&net->xfrm.state_gc_work, xfrm_state_gc_task);
	init_waitqueue_head(&net->xfrm.km_waitq);
	return 0;

out_byspi:
	xfrm_hash_free(net->xfrm.state_bysrc, sz);
out_bysrc:
	xfrm_hash_free(net->xfrm.state_bydst, sz);
out_bydst:
	return -ENOMEM;
}

void xfrm_state_fini(struct net *net)
{
	struct xfrm_audit audit_info;
	unsigned int sz;

	flush_work(&net->xfrm.state_hash_work);
	audit_info.loginuid = INVALID_UID;
	audit_info.sessionid = -1;
	audit_info.secid = 0;
	xfrm_state_flush(net, IPSEC_PROTO_ANY, &audit_info);
	flush_work(&net->xfrm.state_gc_work);

	WARN_ON(!list_empty(&net->xfrm.state_all));

	sz = (net->xfrm.state_hmask + 1) * sizeof(struct hlist_head);
	WARN_ON(!hlist_empty(net->xfrm.state_byspi));
	xfrm_hash_free(net->xfrm.state_byspi, sz);
	WARN_ON(!hlist_empty(net->xfrm.state_bysrc));
	xfrm_hash_free(net->xfrm.state_bysrc, sz);
	WARN_ON(!hlist_empty(net->xfrm.state_bydst));
	xfrm_hash_free(net->xfrm.state_bydst, sz);
}

#ifdef CONFIG_AUDITSYSCALL
static void xfrm_audit_helper_sainfo(struct xfrm_state *x,
				     struct audit_buffer *audit_buf)
{
	struct xfrm_sec_ctx *ctx = x->security;
	u32 spi = ntohl(x->id.spi);

	if (ctx)
		audit_log_format(audit_buf, " sec_alg=%u sec_doi=%u sec_obj=%s",
				 ctx->ctx_alg, ctx->ctx_doi, ctx->ctx_str);

	switch(x->props.family) {
	case AF_INET:
		audit_log_format(audit_buf, " src=%pI4 dst=%pI4",
				 &x->props.saddr.a4, &x->id.daddr.a4);
		break;
	case AF_INET6:
		audit_log_format(audit_buf, " src=%pI6 dst=%pI6",
				 x->props.saddr.a6, x->id.daddr.a6);
		break;
	}

	audit_log_format(audit_buf, " spi=%u(0x%x)", spi, spi);
}

static void xfrm_audit_helper_pktinfo(struct sk_buff *skb, u16 family,
				      struct audit_buffer *audit_buf)
{
	const struct iphdr *iph4;
	const struct ipv6hdr *iph6;

	switch (family) {
	case AF_INET:
		iph4 = ip_hdr(skb);
		audit_log_format(audit_buf, " src=%pI4 dst=%pI4",
				 &iph4->saddr, &iph4->daddr);
		break;
	case AF_INET6:
		iph6 = ipv6_hdr(skb);
		audit_log_format(audit_buf,
				 " src=%pI6 dst=%pI6 flowlbl=0x%x%02x%02x",
				 &iph6->saddr,&iph6->daddr,
				 iph6->flow_lbl[0] & 0x0f,
				 iph6->flow_lbl[1],
				 iph6->flow_lbl[2]);
		break;
	}
}

void xfrm_audit_state_add(struct xfrm_state *x, int result,
			  kuid_t auid, u32 sessionid, u32 secid)
{
	struct audit_buffer *audit_buf;

	audit_buf = xfrm_audit_start("SAD-add");
	if (audit_buf == NULL)
		return;
	xfrm_audit_helper_usrinfo(auid, sessionid, secid, audit_buf);
	xfrm_audit_helper_sainfo(x, audit_buf);
	audit_log_format(audit_buf, " res=%u", result);
	audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_state_add);

void xfrm_audit_state_delete(struct xfrm_state *x, int result,
			     kuid_t auid, u32 sessionid, u32 secid)
{
	struct audit_buffer *audit_buf;

	audit_buf = xfrm_audit_start("SAD-delete");
	if (audit_buf == NULL)
		return;
	xfrm_audit_helper_usrinfo(auid, sessionid, secid, audit_buf);
	xfrm_audit_helper_sainfo(x, audit_buf);
	audit_log_format(audit_buf, " res=%u", result);
	audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_state_delete);

void xfrm_audit_state_replay_overflow(struct xfrm_state *x,
				      struct sk_buff *skb)
{
	struct audit_buffer *audit_buf;
	u32 spi;

	audit_buf = xfrm_audit_start("SA-replay-overflow");
	if (audit_buf == NULL)
		return;
	xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf);
	/* don't record the sequence number because it's inherent in this kind
	 * of audit message */
	spi = ntohl(x->id.spi);
	audit_log_format(audit_buf, " spi=%u(0x%x)", spi, spi);
	audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_state_replay_overflow);

void xfrm_audit_state_replay(struct xfrm_state *x,
			     struct sk_buff *skb, __be32 net_seq)
{
	struct audit_buffer *audit_buf;
	u32 spi;

	audit_buf = xfrm_audit_start("SA-replayed-pkt");
	if (audit_buf == NULL)
		return;
	xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf);
	spi = ntohl(x->id.spi);
	audit_log_format(audit_buf, " spi=%u(0x%x) seqno=%u",
			 spi, spi, ntohl(net_seq));
	audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_state_replay);

void xfrm_audit_state_notfound_simple(struct sk_buff *skb, u16 family)
{
	struct audit_buffer *audit_buf;

	audit_buf = xfrm_audit_start("SA-notfound");
	if (audit_buf == NULL)
		return;
	xfrm_audit_helper_pktinfo(skb, family, audit_buf);
	audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_state_notfound_simple);

void xfrm_audit_state_notfound(struct sk_buff *skb, u16 family,
			       __be32 net_spi, __be32 net_seq)
{
	struct audit_buffer *audit_buf;
	u32 spi;

	audit_buf = xfrm_audit_start("SA-notfound");
	if (audit_buf == NULL)
		return;
	xfrm_audit_helper_pktinfo(skb, family, audit_buf);
	spi = ntohl(net_spi);
	audit_log_format(audit_buf, " spi=%u(0x%x) seqno=%u",
			 spi, spi, ntohl(net_seq));
	audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_state_notfound);

void xfrm_audit_state_icvfail(struct xfrm_state *x,
			      struct sk_buff *skb, u8 proto)
{
	struct audit_buffer *audit_buf;
	__be32 net_spi;
	__be32 net_seq;

	audit_buf = xfrm_audit_start("SA-icv-failure");
	if (audit_buf == NULL)
		return;
	xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf);
	if (xfrm_parse_spi(skb, proto, &net_spi, &net_seq) == 0) {
		u32 spi = ntohl(net_spi);
		audit_log_format(audit_buf, " spi=%u(0x%x) seqno=%u",
				 spi, spi, ntohl(net_seq));
	}
	audit_log_end(audit_buf);
}
EXPORT_SYMBOL_GPL(xfrm_audit_state_icvfail);
#endif /* CONFIG_AUDITSYSCALL */