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 000000000000..80828078733d
--- /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();
+}
+