1 files changed, 1367 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
new file mode 100644
index 0000000..8082807
--- /dev/null
+++ b/net/xfrm/xfrm_policy.c
@@ -0,0 +1,1367 @@
+/* 
+ * 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 <asm/bug.h>
+#include <linux/config.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/module.h>
+#include <net/xfrm.h>
+#include <net/ip.h>
+
+DECLARE_MUTEX(xfrm_cfg_sem);
+EXPORT_SYMBOL(xfrm_cfg_sem);
+
+static DEFINE_RWLOCK(xfrm_policy_lock);
+
+struct xfrm_policy *xfrm_policy_list[XFRM_POLICY_MAX*2];
+EXPORT_SYMBOL(xfrm_policy_list);
+
+static DEFINE_RWLOCK(xfrm_policy_afinfo_lock);
+static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO];
+
+static kmem_cache_t *xfrm_dst_cache;
+
+static struct work_struct xfrm_policy_gc_work;
+static struct list_head xfrm_policy_gc_list =
+	LIST_HEAD_INIT(xfrm_policy_gc_list);
+static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
+
+static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
+static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
+
+int xfrm_register_type(struct xfrm_type *type, unsigned short family)
+{
+	struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+	struct xfrm_type_map *typemap;
+	int err = 0;
+
+	if (unlikely(afinfo == NULL))
+		return -EAFNOSUPPORT;
+	typemap = afinfo->type_map;
+
+	write_lock(&typemap->lock);
+	if (likely(typemap->map[type->proto] == NULL))
+		typemap->map[type->proto] = type;
+	else
+		err = -EEXIST;
+	write_unlock(&typemap->lock);
+	xfrm_policy_put_afinfo(afinfo);
+	return err;
+}
+EXPORT_SYMBOL(xfrm_register_type);
+
+int xfrm_unregister_type(struct xfrm_type *type, unsigned short family)
+{
+	struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+	struct xfrm_type_map *typemap;
+	int err = 0;
+
+	if (unlikely(afinfo == NULL))
+		return -EAFNOSUPPORT;
+	typemap = afinfo->type_map;
+
+	write_lock(&typemap->lock);
+	if (unlikely(typemap->map[type->proto] != type))
+		err = -ENOENT;
+	else
+		typemap->map[type->proto] = NULL;
+	write_unlock(&typemap->lock);
+	xfrm_policy_put_afinfo(afinfo);
+	return err;
+}
+EXPORT_SYMBOL(xfrm_unregister_type);
+
+struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
+{
+	struct xfrm_policy_afinfo *afinfo;
+	struct xfrm_type_map *typemap;
+	struct xfrm_type *type;
+	int modload_attempted = 0;
+
+retry:
+	afinfo = xfrm_policy_get_afinfo(family);
+	if (unlikely(afinfo == NULL))
+		return NULL;
+	typemap = afinfo->type_map;
+
+	read_lock(&typemap->lock);
+	type = typemap->map[proto];
+	if (unlikely(type && !try_module_get(type->owner)))
+		type = NULL;
+	read_unlock(&typemap->lock);
+	if (!type && !modload_attempted) {
+		xfrm_policy_put_afinfo(afinfo);
+		request_module("xfrm-type-%d-%d",
+			       (int) family, (int) proto);
+		modload_attempted = 1;
+		goto retry;
+	}
+
+	xfrm_policy_put_afinfo(afinfo);
+	return type;
+}
+EXPORT_SYMBOL(xfrm_get_type);
+
+int xfrm_dst_lookup(struct xfrm_dst **dst, struct flowi *fl, 
+		    unsigned short family)
+{
+	struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+	int err = 0;
+
+	if (unlikely(afinfo == NULL))
+		return -EAFNOSUPPORT;
+
+	if (likely(afinfo->dst_lookup != NULL))
+		err = afinfo->dst_lookup(dst, fl);
+	else
+		err = -EINVAL;
+	xfrm_policy_put_afinfo(afinfo);
+	return err;
+}
+EXPORT_SYMBOL(xfrm_dst_lookup);
+
+void xfrm_put_type(struct xfrm_type *type)
+{
+	module_put(type->owner);
+}
+
+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(unsigned long data)
+{
+	struct xfrm_policy *xp = (struct xfrm_policy*)data;
+	unsigned long now = (unsigned long)xtime.tv_sec;
+	long next = LONG_MAX;
+	int warn = 0;
+	int dir;
+
+	read_lock(&xp->lock);
+
+	if (xp->dead)
+		goto out;
+
+	dir = xp->index & 7;
+
+	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);
+	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);
+	km_policy_expired(xp, dir, 1);
+	xfrm_policy_delete(xp, dir);
+	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(int gfp)
+{
+	struct xfrm_policy *policy;
+
+	policy = kmalloc(sizeof(struct xfrm_policy), gfp);
+
+	if (policy) {
+		memset(policy, 0, sizeof(struct xfrm_policy));
+		atomic_set(&policy->refcnt, 1);
+		rwlock_init(&policy->lock);
+		init_timer(&policy->timer);
+		policy->timer.data = (unsigned long)policy;
+		policy->timer.function = xfrm_policy_timer;
+	}
+	return policy;
+}
+EXPORT_SYMBOL(xfrm_policy_alloc);
+
+/* Destroy xfrm_policy: descendant resources must be released to this moment. */
+
+void __xfrm_policy_destroy(struct xfrm_policy *policy)
+{
+	if (!policy->dead)
+		BUG();
+
+	if (policy->bundles)
+		BUG();
+
+	if (del_timer(&policy->timer))
+		BUG();
+
+	kfree(policy);
+}
+EXPORT_SYMBOL(__xfrm_policy_destroy);
+
+static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
+{
+	struct dst_entry *dst;
+
+	while ((dst = policy->bundles) != NULL) {
+		policy->bundles = dst->next;
+		dst_free(dst);
+	}
+
+	if (del_timer(&policy->timer))
+		atomic_dec(&policy->refcnt);
+
+	if (atomic_read(&policy->refcnt) > 1)
+		flow_cache_flush();
+
+	xfrm_pol_put(policy);
+}
+
+static void xfrm_policy_gc_task(void *data)
+{
+	struct xfrm_policy *policy;
+	struct list_head *entry, *tmp;
+	struct list_head gc_list = LIST_HEAD_INIT(gc_list);
+
+	spin_lock_bh(&xfrm_policy_gc_lock);
+	list_splice_init(&xfrm_policy_gc_list, &gc_list);
+	spin_unlock_bh(&xfrm_policy_gc_lock);
+
+	list_for_each_safe(entry, tmp, &gc_list) {
+		policy = list_entry(entry, struct xfrm_policy, list);
+		xfrm_policy_gc_kill(policy);
+	}
+}
+
+/* Rule must be locked. Release descentant resources, announce
+ * entry dead. The rule must be unlinked from lists to the moment.
+ */
+
+static void xfrm_policy_kill(struct xfrm_policy *policy)
+{
+	int dead;
+
+	write_lock_bh(&policy->lock);
+	dead = policy->dead;
+	policy->dead = 1;
+	write_unlock_bh(&policy->lock);
+
+	if (unlikely(dead)) {
+		WARN_ON(1);
+		return;
+	}
+
+	spin_lock(&xfrm_policy_gc_lock);
+	list_add(&policy->list, &xfrm_policy_gc_list);
+	spin_unlock(&xfrm_policy_gc_lock);
+
+	schedule_work(&xfrm_policy_gc_work);
+}
+
+/* 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(int dir)
+{
+	u32 idx;
+	struct xfrm_policy *p;
+	static u32 idx_generator;
+
+	for (;;) {
+		idx = (idx_generator | dir);
+		idx_generator += 8;
+		if (idx == 0)
+			idx = 8;
+		for (p = xfrm_policy_list[dir]; p; p = p->next) {
+			if (p->index == idx)
+				break;
+		}
+		if (!p)
+			return idx;
+	}
+}
+
+int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
+{
+	struct xfrm_policy *pol, **p;
+	struct xfrm_policy *delpol = NULL;
+	struct xfrm_policy **newpos = NULL;
+
+	write_lock_bh(&xfrm_policy_lock);
+	for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL;) {
+		if (!delpol && memcmp(&policy->selector, &pol->selector, sizeof(pol->selector)) == 0) {
+			if (excl) {
+				write_unlock_bh(&xfrm_policy_lock);
+				return -EEXIST;
+			}
+			*p = pol->next;
+			delpol = pol;
+			if (policy->priority > pol->priority)
+				continue;
+		} else if (policy->priority >= pol->priority) {
+			p = &pol->next;
+			continue;
+		}
+		if (!newpos)
+			newpos = p;
+		if (delpol)
+			break;
+		p = &pol->next;
+	}
+	if (newpos)
+		p = newpos;
+	xfrm_pol_hold(policy);
+	policy->next = *p;
+	*p = policy;
+	atomic_inc(&flow_cache_genid);
+	policy->index = delpol ? delpol->index : xfrm_gen_index(dir);
+	policy->curlft.add_time = (unsigned long)xtime.tv_sec;
+	policy->curlft.use_time = 0;
+	if (!mod_timer(&policy->timer, jiffies + HZ))
+		xfrm_pol_hold(policy);
+	write_unlock_bh(&xfrm_policy_lock);
+
+	if (delpol) {
+		xfrm_policy_kill(delpol);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(xfrm_policy_insert);
+
+struct xfrm_policy *xfrm_policy_bysel(int dir, struct xfrm_selector *sel,
+				      int delete)
+{
+	struct xfrm_policy *pol, **p;
+
+	write_lock_bh(&xfrm_policy_lock);
+	for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) {
+		if (memcmp(sel, &pol->selector, sizeof(*sel)) == 0) {
+			xfrm_pol_hold(pol);
+			if (delete)
+				*p = pol->next;
+			break;
+		}
+	}
+	write_unlock_bh(&xfrm_policy_lock);
+
+	if (pol && delete) {
+		atomic_inc(&flow_cache_genid);
+		xfrm_policy_kill(pol);
+	}
+	return pol;
+}
+EXPORT_SYMBOL(xfrm_policy_bysel);
+
+struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete)
+{
+	struct xfrm_policy *pol, **p;
+
+	write_lock_bh(&xfrm_policy_lock);
+	for (p = &xfrm_policy_list[id & 7]; (pol=*p)!=NULL; p = &pol->next) {
+		if (pol->index == id) {
+			xfrm_pol_hold(pol);
+			if (delete)
+				*p = pol->next;
+			break;
+		}
+	}
+	write_unlock_bh(&xfrm_policy_lock);
+
+	if (pol && delete) {
+		atomic_inc(&flow_cache_genid);
+		xfrm_policy_kill(pol);
+	}
+	return pol;
+}
+EXPORT_SYMBOL(xfrm_policy_byid);
+
+void xfrm_policy_flush(void)
+{
+	struct xfrm_policy *xp;
+	int dir;
+
+	write_lock_bh(&xfrm_policy_lock);
+	for (dir = 0; dir < XFRM_POLICY_MAX; dir++) {
+		while ((xp = xfrm_policy_list[dir]) != NULL) {
+			xfrm_policy_list[dir] = xp->next;
+			write_unlock_bh(&xfrm_policy_lock);
+
+			xfrm_policy_kill(xp);
+
+			write_lock_bh(&xfrm_policy_lock);
+		}
+	}
+	atomic_inc(&flow_cache_genid);
+	write_unlock_bh(&xfrm_policy_lock);
+}
+EXPORT_SYMBOL(xfrm_policy_flush);
+
+int xfrm_policy_walk(int (*func)(struct xfrm_policy *, int, int, void*),
+		     void *data)
+{
+	struct xfrm_policy *xp;
+	int dir;
+	int count = 0;
+	int error = 0;
+
+	read_lock_bh(&xfrm_policy_lock);
+	for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
+		for (xp = xfrm_policy_list[dir]; xp; xp = xp->next)
+			count++;
+	}
+
+	if (count == 0) {
+		error = -ENOENT;
+		goto out;
+	}
+
+	for (dir = 0; dir < 2*XFRM_POLICY_MAX; dir++) {
+		for (xp = xfrm_policy_list[dir]; xp; xp = xp->next) {
+			error = func(xp, dir%XFRM_POLICY_MAX, --count, data);
+			if (error)
+				goto out;
+		}
+	}
+
+out:
+	read_unlock_bh(&xfrm_policy_lock);
+	return error;
+}
+EXPORT_SYMBOL(xfrm_policy_walk);
+
+/* Find policy to apply to this flow. */
+
+static void xfrm_policy_lookup(struct flowi *fl, u16 family, u8 dir,
+			       void **objp, atomic_t **obj_refp)
+{
+	struct xfrm_policy *pol;
+
+	read_lock_bh(&xfrm_policy_lock);
+	for (pol = xfrm_policy_list[dir]; pol; pol = pol->next) {
+		struct xfrm_selector *sel = &pol->selector;
+		int match;
+
+		if (pol->family != family)
+			continue;
+
+		match = xfrm_selector_match(sel, fl, family);
+		if (match) {
+			xfrm_pol_hold(pol);
+			break;
+		}
+	}
+	read_unlock_bh(&xfrm_policy_lock);
+	if ((*objp = (void *) pol) != NULL)
+		*obj_refp = &pol->refcnt;
+}
+
+static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struct flowi *fl)
+{
+	struct xfrm_policy *pol;
+
+	read_lock_bh(&xfrm_policy_lock);
+	if ((pol = sk->sk_policy[dir]) != NULL) {
+		int match = xfrm_selector_match(&pol->selector, fl,
+						sk->sk_family);
+		if (match)
+			xfrm_pol_hold(pol);
+		else
+			pol = NULL;
+	}
+	read_unlock_bh(&xfrm_policy_lock);
+	return pol;
+}
+
+static void __xfrm_policy_link(struct xfrm_policy *pol, int dir)
+{
+	pol->next = xfrm_policy_list[dir];
+	xfrm_policy_list[dir] = pol;
+	xfrm_pol_hold(pol);
+}
+
+static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol,
+						int dir)
+{
+	struct xfrm_policy **polp;
+
+	for (polp = &xfrm_policy_list[dir];
+	     *polp != NULL; polp = &(*polp)->next) {
+		if (*polp == pol) {
+			*polp = pol->next;
+			return pol;
+		}
+	}
+	return NULL;
+}
+
+void xfrm_policy_delete(struct xfrm_policy *pol, int dir)
+{
+	write_lock_bh(&xfrm_policy_lock);
+	pol = __xfrm_policy_unlink(pol, dir);
+	write_unlock_bh(&xfrm_policy_lock);
+	if (pol) {
+		if (dir < XFRM_POLICY_MAX)
+			atomic_inc(&flow_cache_genid);
+		xfrm_policy_kill(pol);
+	}
+}
+
+int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
+{
+	struct xfrm_policy *old_pol;
+
+	write_lock_bh(&xfrm_policy_lock);
+	old_pol = sk->sk_policy[dir];
+	sk->sk_policy[dir] = pol;
+	if (pol) {
+		pol->curlft.add_time = (unsigned long)xtime.tv_sec;
+		pol->index = xfrm_gen_index(XFRM_POLICY_MAX+dir);
+		__xfrm_policy_link(pol, XFRM_POLICY_MAX+dir);
+	}
+	if (old_pol)
+		__xfrm_policy_unlink(old_pol, XFRM_POLICY_MAX+dir);
+	write_unlock_bh(&xfrm_policy_lock);
+
+	if (old_pol) {
+		xfrm_policy_kill(old_pol);
+	}
+	return 0;
+}
+
+static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)
+{
+	struct xfrm_policy *newp = xfrm_policy_alloc(GFP_ATOMIC);
+
+	if (newp) {
+		newp->selector = old->selector;
+		newp->lft = old->lft;
+		newp->curlft = old->curlft;
+		newp->action = old->action;
+		newp->flags = old->flags;
+		newp->xfrm_nr = old->xfrm_nr;
+		newp->index = old->index;
+		memcpy(newp->xfrm_vec, old->xfrm_vec,
+		       newp->xfrm_nr*sizeof(struct xfrm_tmpl));
+		write_lock_bh(&xfrm_policy_lock);
+		__xfrm_policy_link(newp, XFRM_POLICY_MAX+dir);
+		write_unlock_bh(&xfrm_policy_lock);
+		xfrm_pol_put(newp);
+	}
+	return newp;
+}
+
+int __xfrm_sk_clone_policy(struct sock *sk)
+{
+	struct xfrm_policy *p0 = sk->sk_policy[0],
+			   *p1 = sk->sk_policy[1];
+
+	sk->sk_policy[0] = sk->sk_policy[1] = NULL;
+	if (p0 && (sk->sk_policy[0] = clone_policy(p0, 0)) == NULL)
+		return -ENOMEM;
+	if (p1 && (sk->sk_policy[1] = clone_policy(p1, 1)) == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+/* Resolve list of templates for the flow, given policy. */
+
+static int
+xfrm_tmpl_resolve(struct xfrm_policy *policy, struct flowi *fl,
+		  struct xfrm_state **xfrm,
+		  unsigned short family)
+{
+	int nx;
+	int i, error;
+	xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
+	xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);
+
+	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) {
+			remote = &tmpl->id.daddr;
+			local = &tmpl->saddr;
+		}
+
+		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);
+		}
+
+		if (!tmpl->optional)
+			goto fail;
+	}
+	return nx;
+
+fail:
+	for (nx--; nx>=0; nx--)
+		xfrm_state_put(xfrm[nx]);
+	return error;
+}
+
+/* Check that the bundle accepts the flow and its components are
+ * still valid.
+ */
+
+static struct dst_entry *
+xfrm_find_bundle(struct flowi *fl, struct xfrm_policy *policy, unsigned short family)
+{
+	struct dst_entry *x;
+	struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+	if (unlikely(afinfo == NULL))
+		return ERR_PTR(-EINVAL);
+	x = afinfo->find_bundle(fl, policy);
+	xfrm_policy_put_afinfo(afinfo);
+	return x;
+}
+
+/* Allocate chain of dst_entry's, attach known xfrm's, calculate
+ * all the metrics... Shortly, bundle a bundle.
+ */
+
+static int
+xfrm_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
+		   struct flowi *fl, struct dst_entry **dst_p,
+		   unsigned short family)
+{
+	int err;
+	struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+	if (unlikely(afinfo == NULL))
+		return -EINVAL;
+	err = afinfo->bundle_create(policy, xfrm, nx, fl, dst_p);
+	xfrm_policy_put_afinfo(afinfo);
+	return err;
+}
+
+static inline int policy_to_flow_dir(int dir)
+{
+	if (XFRM_POLICY_IN == FLOW_DIR_IN &&
+	    XFRM_POLICY_OUT == FLOW_DIR_OUT &&
+	    XFRM_POLICY_FWD == FLOW_DIR_FWD)
+		return dir;
+	switch (dir) {
+	default:
+	case XFRM_POLICY_IN:
+		return FLOW_DIR_IN;
+	case XFRM_POLICY_OUT:
+		return FLOW_DIR_OUT;
+	case XFRM_POLICY_FWD:
+		return FLOW_DIR_FWD;
+	};
+}
+
+static int stale_bundle(struct dst_entry *dst);
+
+/* Main function: finds/creates a bundle for given flow.
+ *
+ * At the moment we eat a raw IP route. Mostly to speed up lookups
+ * on interfaces with disabled IPsec.
+ */
+int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
+		struct sock *sk, int flags)
+{
+	struct xfrm_policy *policy;
+	struct xfrm_state *xfrm[XFRM_MAX_DEPTH];
+	struct dst_entry *dst, *dst_orig = *dst_p;
+	int nx = 0;
+	int err;
+	u32 genid;
+	u16 family = dst_orig->ops->family;
+restart:
+	genid = atomic_read(&flow_cache_genid);
+	policy = NULL;
+	if (sk && sk->sk_policy[1])
+		policy = xfrm_sk_policy_lookup(sk, XFRM_POLICY_OUT, fl);
+
+	if (!policy) {
+		/* To accelerate a bit...  */
+		if ((dst_orig->flags & DST_NOXFRM) || !xfrm_policy_list[XFRM_POLICY_OUT])
+			return 0;
+
+		policy = flow_cache_lookup(fl, family,
+					   policy_to_flow_dir(XFRM_POLICY_OUT),
+					   xfrm_policy_lookup);
+	}
+
+	if (!policy)
+		return 0;
+
+	policy->curlft.use_time = (unsigned long)xtime.tv_sec;
+
+	switch (policy->action) {
+	case XFRM_POLICY_BLOCK:
+		/* Prohibit the flow */
+		xfrm_pol_put(policy);
+		return -EPERM;
+
+	case XFRM_POLICY_ALLOW:
+		if (policy->xfrm_nr == 0) {
+			/* Flow passes not transformed. */
+			xfrm_pol_put(policy);
+			return 0;
+		}
+
+		/* Try to find matching bundle.
+		 *
+		 * LATER: help from flow cache. It is optional, this
+		 * is required only for output policy.
+		 */
+		dst = xfrm_find_bundle(fl, policy, family);
+		if (IS_ERR(dst)) {
+			xfrm_pol_put(policy);
+			return PTR_ERR(dst);
+		}
+
+		if (dst)
+			break;
+
+		nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
+
+		if (unlikely(nx<0)) {
+			err = nx;
+			if (err == -EAGAIN && flags) {
+				DECLARE_WAITQUEUE(wait, current);
+
+				add_wait_queue(&km_waitq, &wait);
+				set_current_state(TASK_INTERRUPTIBLE);
+				schedule();
+				set_current_state(TASK_RUNNING);
+				remove_wait_queue(&km_waitq, &wait);
+
+				nx = xfrm_tmpl_resolve(policy, fl, xfrm, family);
+
+				if (nx == -EAGAIN && signal_pending(current)) {
+					err = -ERESTART;
+					goto error;
+				}
+				if (nx == -EAGAIN ||
+				    genid != atomic_read(&flow_cache_genid)) {
+					xfrm_pol_put(policy);
+					goto restart;
+				}
+				err = nx;
+			}
+			if (err < 0)
+				goto error;
+		}
+		if (nx == 0) {
+			/* Flow passes not transformed. */
+			xfrm_pol_put(policy);
+			return 0;
+		}
+
+		dst = dst_orig;
+		err = xfrm_bundle_create(policy, xfrm, nx, fl, &dst, family);
+
+		if (unlikely(err)) {
+			int i;
+			for (i=0; i<nx; i++)
+				xfrm_state_put(xfrm[i]);
+			goto error;
+		}
+
+		write_lock_bh(&policy->lock);
+		if (unlikely(policy->dead || stale_bundle(dst))) {
+			/* Wow! While we worked on resolving, this
+			 * policy has gone. Retry. It is not paranoia,
+			 * we just cannot enlist new bundle to dead object.
+			 * We can't enlist stable bundles either.
+			 */
+			write_unlock_bh(&policy->lock);
+
+			xfrm_pol_put(policy);
+			if (dst)
+				dst_free(dst);
+			goto restart;
+		}
+		dst->next = policy->bundles;
+		policy->bundles = dst;
+		dst_hold(dst);
+		write_unlock_bh(&policy->lock);
+	}
+	*dst_p = dst;
+	dst_release(dst_orig);
+	xfrm_pol_put(policy);
+	return 0;
+
+error:
+	dst_release(dst_orig);
+	xfrm_pol_put(policy);
+	*dst_p = NULL;
+	return err;
+}
+EXPORT_SYMBOL(xfrm_lookup);
+
+/* When skb is transformed back to its "native" form, we have to
+ * check policy restrictions. At the moment we make this in maximally
+ * stupid way. Shame on me. :-) Of course, connected sockets must
+ * have policy cached at them.
+ */
+
+static inline int
+xfrm_state_ok(struct xfrm_tmpl *tmpl, struct xfrm_state *x, 
+	      unsigned short family)
+{
+	if (xfrm_state_kern(x))
+		return tmpl->optional && !xfrm_state_addr_cmp(tmpl, x, family);
+	return	x->id.proto == tmpl->id.proto &&
+		(x->id.spi == tmpl->id.spi || !tmpl->id.spi) &&
+		(x->props.reqid == tmpl->reqid || !tmpl->reqid) &&
+		x->props.mode == tmpl->mode &&
+		(tmpl->aalgos & (1<<x->props.aalgo)) &&
+		!(x->props.mode && xfrm_state_addr_cmp(tmpl, x, family));
+}
+
+static inline int
+xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
+	       unsigned short family)
+{
+	int idx = start;
+
+	if (tmpl->optional) {
+		if (!tmpl->mode)
+			return start;
+	} else
+		start = -1;
+	for (; idx < sp->len; idx++) {
+		if (xfrm_state_ok(tmpl, sp->x[idx].xvec, family))
+			return ++idx;
+		if (sp->x[idx].xvec->props.mode)
+			break;
+	}
+	return start;
+}
+
+static int
+_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
+{
+	struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
+
+	if (unlikely(afinfo == NULL))
+		return -EAFNOSUPPORT;
+
+	afinfo->decode_session(skb, fl);
+	xfrm_policy_put_afinfo(afinfo);
+	return 0;
+}
+
+static inline int secpath_has_tunnel(struct sec_path *sp, int k)
+{
+	for (; k < sp->len; k++) {
+		if (sp->x[k].xvec->props.mode)
+			return 1;
+	}
+
+	return 0;
+}
+
+int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, 
+			unsigned short family)
+{
+	struct xfrm_policy *pol;
+	struct flowi fl;
+
+	if (_decode_session(skb, &fl, family) < 0)
+		return 0;
+
+	/* First, check used SA against their selectors. */
+	if (skb->sp) {
+		int i;
+
+		for (i=skb->sp->len-1; i>=0; i--) {
+		  struct sec_decap_state *xvec = &(skb->sp->x[i]);
+			if (!xfrm_selector_match(&xvec->xvec->sel, &fl, family))
+				return 0;
+
+			/* If there is a post_input processor, try running it */
+			if (xvec->xvec->type->post_input &&
+			    (xvec->xvec->type->post_input)(xvec->xvec,
+							   &(xvec->decap),
+							   skb) != 0)
+				return 0;
+		}
+	}
+
+	pol = NULL;
+	if (sk && sk->sk_policy[dir])
+		pol = xfrm_sk_policy_lookup(sk, dir, &fl);
+
+	if (!pol)
+		pol = flow_cache_lookup(&fl, family,
+					policy_to_flow_dir(dir),
+					xfrm_policy_lookup);
+
+	if (!pol)
+		return !skb->sp || !secpath_has_tunnel(skb->sp, 0);
+
+	pol->curlft.use_time = (unsigned long)xtime.tv_sec;
+
+	if (pol->action == XFRM_POLICY_ALLOW) {
+		struct sec_path *sp;
+		static struct sec_path dummy;
+		int i, k;
+
+		if ((sp = skb->sp) == NULL)
+			sp = &dummy;
+
+		/* For each tunnel xfrm, find the first matching tmpl.
+		 * For each tmpl before that, find corresponding xfrm.
+		 * Order is _important_. Later we will implement
+		 * some barriers, but at the moment barriers
+		 * are implied between each two transformations.
+		 */
+		for (i = pol->xfrm_nr-1, k = 0; i >= 0; i--) {
+			k = xfrm_policy_ok(pol->xfrm_vec+i, sp, k, family);
+			if (k < 0)
+				goto reject;
+		}
+
+		if (secpath_has_tunnel(sp, k))
+			goto reject;
+
+		xfrm_pol_put(pol);
+		return 1;
+	}
+
+reject:
+	xfrm_pol_put(pol);
+	return 0;
+}
+EXPORT_SYMBOL(__xfrm_policy_check);
+
+int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
+{
+	struct flowi fl;
+
+	if (_decode_session(skb, &fl, family) < 0)
+		return 0;
+
+	return xfrm_lookup(&skb->dst, &fl, NULL, 0) == 0;
+}
+EXPORT_SYMBOL(__xfrm_route_forward);
+
+/* Optimize later using cookies and generation ids. */
+
+static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
+{
+	if (!stale_bundle(dst))
+		return dst;
+
+	return NULL;
+}
+
+static int stale_bundle(struct dst_entry *dst)
+{
+	return !xfrm_bundle_ok((struct xfrm_dst *)dst, NULL, AF_UNSPEC);
+}
+
+static void xfrm_dst_destroy(struct dst_entry *dst)
+{
+	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+
+	dst_release(xdst->route);
+
+	if (!dst->xfrm)
+		return;
+	xfrm_state_put(dst->xfrm);
+	dst->xfrm = NULL;
+}
+
+static void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
+			    int unregister)
+{
+	if (!unregister)
+		return;
+
+	while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {
+		dst->dev = &loopback_dev;
+		dev_hold(&loopback_dev);
+		dev_put(dev);
+	}
+}
+
+static void xfrm_link_failure(struct sk_buff *skb)
+{
+	/* Impossible. Such dst must be popped before reaches point of failure. */
+	return;
+}
+
+static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
+{
+	if (dst) {
+		if (dst->obsolete) {
+			dst_release(dst);
+			dst = NULL;
+		}
+	}
+	return dst;
+}
+
+static void xfrm_prune_bundles(int (*func)(struct dst_entry *))
+{
+	int i;
+	struct xfrm_policy *pol;
+	struct dst_entry *dst, **dstp, *gc_list = NULL;
+
+	read_lock_bh(&xfrm_policy_lock);
+	for (i=0; i<2*XFRM_POLICY_MAX; i++) {
+		for (pol = xfrm_policy_list[i]; pol; pol = pol->next) {
+			write_lock(&pol->lock);
+			dstp = &pol->bundles;
+			while ((dst=*dstp) != NULL) {
+				if (func(dst)) {
+					*dstp = dst->next;
+					dst->next = gc_list;
+					gc_list = dst;
+				} else {
+					dstp = &dst->next;
+				}
+			}
+			write_unlock(&pol->lock);
+		}
+	}
+	read_unlock_bh(&xfrm_policy_lock);
+
+	while (gc_list) {
+		dst = gc_list;
+		gc_list = dst->next;
+		dst_free(dst);
+	}
+}
+
+static int unused_bundle(struct dst_entry *dst)
+{
+	return !atomic_read(&dst->__refcnt);
+}
+
+static void __xfrm_garbage_collect(void)
+{
+	xfrm_prune_bundles(unused_bundle);
+}
+
+int xfrm_flush_bundles(void)
+{
+	xfrm_prune_bundles(stale_bundle);
+	return 0;
+}
+
+void xfrm_init_pmtu(struct dst_entry *dst)
+{
+	do {
+		struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+		u32 pmtu, route_mtu_cached;
+
+		pmtu = dst_mtu(dst->child);
+		xdst->child_mtu_cached = pmtu;
+
+		pmtu = xfrm_state_mtu(dst->xfrm, pmtu);
+
+		route_mtu_cached = dst_mtu(xdst->route);
+		xdst->route_mtu_cached = route_mtu_cached;
+
+		if (pmtu > route_mtu_cached)
+			pmtu = route_mtu_cached;
+
+		dst->metrics[RTAX_MTU-1] = pmtu;
+	} while ((dst = dst->next));
+}
+
+EXPORT_SYMBOL(xfrm_init_pmtu);
+
+/* Check that the bundle accepts the flow and its components are
+ * still valid.
+ */
+
+int xfrm_bundle_ok(struct xfrm_dst *first, struct flowi *fl, int family)
+{
+	struct dst_entry *dst = &first->u.dst;
+	struct xfrm_dst *last;
+	u32 mtu;
+
+	if (!dst_check(dst->path, 0) ||
+	    (dst->dev && !netif_running(dst->dev)))
+		return 0;
+
+	last = NULL;
+
+	do {
+		struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+
+		if (fl && !xfrm_selector_match(&dst->xfrm->sel, fl, family))
+			return 0;
+		if (dst->xfrm->km.state != XFRM_STATE_VALID)
+			return 0;
+
+		mtu = dst_mtu(dst->child);
+		if (xdst->child_mtu_cached != mtu) {
+			last = xdst;
+			xdst->child_mtu_cached = mtu;
+		}
+
+		if (!dst_check(xdst->route, 0))
+			return 0;
+		mtu = dst_mtu(xdst->route);
+		if (xdst->route_mtu_cached != mtu) {
+			last = xdst;
+			xdst->route_mtu_cached = mtu;
+		}
+
+		dst = dst->child;
+	} while (dst->xfrm);
+
+	if (likely(!last))
+		return 1;
+
+	mtu = last->child_mtu_cached;
+	for (;;) {
+		dst = &last->u.dst;
+
+		mtu = xfrm_state_mtu(dst->xfrm, mtu);
+		if (mtu > last->route_mtu_cached)
+			mtu = last->route_mtu_cached;
+		dst->metrics[RTAX_MTU-1] = mtu;
+
+		if (last == first)
+			break;
+
+		last = last->u.next;
+		last->child_mtu_cached = mtu;
+	}
+
+	return 1;
+}
+
+EXPORT_SYMBOL(xfrm_bundle_ok);
+
+/* Well... that's _TASK_. We need to scan through transformation
+ * list and figure out what mss tcp should generate in order to
+ * final datagram fit to mtu. Mama mia... :-)
+ *
+ * Apparently, some easy way exists, but we used to choose the most
+ * bizarre ones. :-) So, raising Kalashnikov... tra-ta-ta.
+ *
+ * Consider this function as something like dark humour. :-)
+ */
+static int xfrm_get_mss(struct dst_entry *dst, u32 mtu)
+{
+	int res = mtu - dst->header_len;
+
+	for (;;) {
+		struct dst_entry *d = dst;
+		int m = res;
+
+		do {
+			struct xfrm_state *x = d->xfrm;
+			if (x) {
+				spin_lock_bh(&x->lock);
+				if (x->km.state == XFRM_STATE_VALID &&
+				    x->type && x->type->get_max_size)
+					m = x->type->get_max_size(d->xfrm, m);
+				else
+					m += x->props.header_len;
+				spin_unlock_bh(&x->lock);
+			}
+		} while ((d = d->child) != NULL);
+
+		if (m <= mtu)
+			break;
+		res -= (m - mtu);
+		if (res < 88)
+			return mtu;
+	}
+
+	return res + dst->header_len;
+}
+
+int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
+{
+	int err = 0;
+	if (unlikely(afinfo == NULL))
+		return -EINVAL;
+	if (unlikely(afinfo->family >= NPROTO))
+		return -EAFNOSUPPORT;
+	write_lock(&xfrm_policy_afinfo_lock);
+	if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL))
+		err = -ENOBUFS;
+	else {
+		struct dst_ops *dst_ops = afinfo->dst_ops;
+		if (likely(dst_ops->kmem_cachep == NULL))
+			dst_ops->kmem_cachep = xfrm_dst_cache;
+		if (likely(dst_ops->check == NULL))
+			dst_ops->check = xfrm_dst_check;
+		if (likely(dst_ops->destroy == NULL))
+			dst_ops->destroy = xfrm_dst_destroy;
+		if (likely(dst_ops->ifdown == NULL))
+			dst_ops->ifdown = xfrm_dst_ifdown;
+		if (likely(dst_ops->negative_advice == NULL))
+			dst_ops->negative_advice = xfrm_negative_advice;
+		if (likely(dst_ops->link_failure == NULL))
+			dst_ops->link_failure = xfrm_link_failure;
+		if (likely(dst_ops->get_mss == NULL))
+			dst_ops->get_mss = xfrm_get_mss;
+		if (likely(afinfo->garbage_collect == NULL))
+			afinfo->garbage_collect = __xfrm_garbage_collect;
+		xfrm_policy_afinfo[afinfo->family] = afinfo;
+	}
+	write_unlock(&xfrm_policy_afinfo_lock);
+	return err;
+}
+EXPORT_SYMBOL(xfrm_policy_register_afinfo);
+
+int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo)
+{
+	int err = 0;
+	if (unlikely(afinfo == NULL))
+		return -EINVAL;
+	if (unlikely(afinfo->family >= NPROTO))
+		return -EAFNOSUPPORT;
+	write_lock(&xfrm_policy_afinfo_lock);
+	if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) {
+		if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo))
+			err = -EINVAL;
+		else {
+			struct dst_ops *dst_ops = afinfo->dst_ops;
+			xfrm_policy_afinfo[afinfo->family] = NULL;
+			dst_ops->kmem_cachep = NULL;
+			dst_ops->check = NULL;
+			dst_ops->destroy = NULL;
+			dst_ops->ifdown = NULL;
+			dst_ops->negative_advice = NULL;
+			dst_ops->link_failure = NULL;
+			dst_ops->get_mss = NULL;
+			afinfo->garbage_collect = NULL;
+		}
+	}
+	write_unlock(&xfrm_policy_afinfo_lock);
+	return err;
+}
+EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
+
+static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
+{
+	struct xfrm_policy_afinfo *afinfo;
+	if (unlikely(family >= NPROTO))
+		return NULL;
+	read_lock(&xfrm_policy_afinfo_lock);
+	afinfo = xfrm_policy_afinfo[family];
+	if (likely(afinfo != NULL))
+		read_lock(&afinfo->lock);
+	read_unlock(&xfrm_policy_afinfo_lock);
+	return afinfo;
+}
+
+static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
+{
+	if (unlikely(afinfo == NULL))
+		return;
+	read_unlock(&afinfo->lock);
+}
+
+static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	switch (event) {
+	case NETDEV_DOWN:
+		xfrm_flush_bundles();
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block xfrm_dev_notifier = {
+	xfrm_dev_event,
+	NULL,
+	0
+};
+
+static void __init xfrm_policy_init(void)
+{
+	xfrm_dst_cache = kmem_cache_create("xfrm_dst_cache",
+					   sizeof(struct xfrm_dst),
+					   0, SLAB_HWCACHE_ALIGN,
+					   NULL, NULL);
+	if (!xfrm_dst_cache)
+		panic("XFRM: failed to allocate xfrm_dst_cache\n");
+
+	INIT_WORK(&xfrm_policy_gc_work, xfrm_policy_gc_task, NULL);
+	register_netdevice_notifier(&xfrm_dev_notifier);
+}
+
+void __init xfrm_init(void)
+{
+	xfrm_state_init();
+	xfrm_policy_init();
+	xfrm_input_init();
+}
+