Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[mirror_ubuntu-bionic-kernel.git] / net / netfilter / ipset / ip_set_hash_gen.h

/* Copyright (C) 2013 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#ifndef _IP_SET_HASH_GEN_H
#define _IP_SET_HASH_GEN_H

#include <linux/rcupdate.h>
#include <linux/jhash.h>
#include <linux/netfilter/ipset/ip_set_timeout.h>
#ifndef rcu_dereference_bh
#define rcu_dereference_bh(p)   rcu_dereference(p)
#endif

#define rcu_dereference_bh_nfnl(p)      rcu_dereference_bh_check(p, 1)

/* Hashing which uses arrays to resolve clashing. The hash table is resized
 * (doubled) when searching becomes too long.
 * Internally jhash is used with the assumption that the size of the
 * stored data is a multiple of sizeof(u32). If storage supports timeout,
 * the timeout field must be the last one in the data structure - that field
 * is ignored when computing the hash key.
 *
 * Readers and resizing
 *
 * Resizing can be triggered by userspace command only, and those
 * are serialized by the nfnl mutex. During resizing the set is
 * read-locked, so the only possible concurrent operations are
 * the kernel side readers. Those must be protected by proper RCU locking.
 */

/* Number of elements to store in an initial array block */
#define AHASH_INIT_SIZE                 4
/* Max number of elements to store in an array block */
#define AHASH_MAX_SIZE                  (3*AHASH_INIT_SIZE)

/* Max number of elements can be tuned */
#ifdef IP_SET_HASH_WITH_MULTI
#define AHASH_MAX(h)                    ((h)->ahash_max)

static inline u8
tune_ahash_max(u8 curr, u32 multi)
{
        u32 n;

        if (multi < curr)
                return curr;

        n = curr + AHASH_INIT_SIZE;
        /* Currently, at listing one hash bucket must fit into a message.
         * Therefore we have a hard limit here.
         */
        return n > curr && n <= 64 ? n : curr;
}
#define TUNE_AHASH_MAX(h, multi)        \
        ((h)->ahash_max = tune_ahash_max((h)->ahash_max, multi))
#else
#define AHASH_MAX(h)                    AHASH_MAX_SIZE
#define TUNE_AHASH_MAX(h, multi)
#endif

/* A hash bucket */
struct hbucket {
        void *value;            /* the array of the values */
        u8 size;                /* size of the array */
        u8 pos;                 /* position of the first free entry */
};

/* The hash table: the table size stored here in order to make resizing easy */
struct htable {
        u8 htable_bits;         /* size of hash table == 2^htable_bits */
        struct hbucket bucket[0]; /* hashtable buckets */
};

#define hbucket(h, i)           (&((h)->bucket[i]))

#ifndef IPSET_NET_COUNT
#define IPSET_NET_COUNT         1
#endif

/* Book-keeping of the prefixes added to the set */
struct net_prefixes {
        u32 nets[IPSET_NET_COUNT]; /* number of elements per cidr */
        u8 cidr[IPSET_NET_COUNT];  /* the different cidr values in the set */
};

/* Compute the hash table size */
static size_t
htable_size(u8 hbits)
{
        size_t hsize;

        /* We must fit both into u32 in jhash and size_t */
        if (hbits > 31)
                return 0;
        hsize = jhash_size(hbits);
        if ((((size_t)-1) - sizeof(struct htable))/sizeof(struct hbucket)
            < hsize)
                return 0;

        return hsize * sizeof(struct hbucket) + sizeof(struct htable);
}

/* Compute htable_bits from the user input parameter hashsize */
static u8
htable_bits(u32 hashsize)
{
        /* Assume that hashsize == 2^htable_bits */
        u8 bits = fls(hashsize - 1);
        if (jhash_size(bits) != hashsize)
                /* Round up to the first 2^n value */
                bits = fls(hashsize);

        return bits;
}

static int
hbucket_elem_add(struct hbucket *n, u8 ahash_max, size_t dsize)
{
        if (n->pos >= n->size) {
                void *tmp;

                if (n->size >= ahash_max)
                        /* Trigger rehashing */
                        return -EAGAIN;

                tmp = kzalloc((n->size + AHASH_INIT_SIZE) * dsize,
                              GFP_ATOMIC);
                if (!tmp)
                        return -ENOMEM;
                if (n->size) {
                        memcpy(tmp, n->value, n->size * dsize);
                        kfree(n->value);
                }
                n->value = tmp;
                n->size += AHASH_INIT_SIZE;
        }
        return 0;
}

#ifdef IP_SET_HASH_WITH_NETS
#if IPSET_NET_COUNT > 1
#define __CIDR(cidr, i)         (cidr[i])
#else
#define __CIDR(cidr, i)         (cidr)
#endif
#ifdef IP_SET_HASH_WITH_NETS_PACKED
/* When cidr is packed with nomatch, cidr - 1 is stored in the entry */
#define CIDR(cidr, i)           (__CIDR(cidr, i) + 1)
#else
#define CIDR(cidr, i)           (__CIDR(cidr, i))
#endif

#define SET_HOST_MASK(family)   (family == AF_INET ? 32 : 128)

#ifdef IP_SET_HASH_WITH_MULTI
#define NLEN(family)            (SET_HOST_MASK(family) + 1)
#else
#define NLEN(family)            SET_HOST_MASK(family)
#endif

#else
#define NLEN(family)            0
#endif /* IP_SET_HASH_WITH_NETS */

#endif /* _IP_SET_HASH_GEN_H */

/* Family dependent templates */

#undef ahash_data
#undef mtype_data_equal
#undef mtype_do_data_match
#undef mtype_data_set_flags
#undef mtype_data_reset_flags
#undef mtype_data_netmask
#undef mtype_data_list
#undef mtype_data_next
#undef mtype_elem

#undef mtype_ahash_destroy
#undef mtype_ext_cleanup
#undef mtype_add_cidr
#undef mtype_del_cidr
#undef mtype_ahash_memsize
#undef mtype_flush
#undef mtype_destroy
#undef mtype_gc_init
#undef mtype_same_set
#undef mtype_kadt
#undef mtype_uadt
#undef mtype

#undef mtype_add
#undef mtype_del
#undef mtype_test_cidrs
#undef mtype_test
#undef mtype_expire
#undef mtype_resize
#undef mtype_head
#undef mtype_list
#undef mtype_gc
#undef mtype_gc_init
#undef mtype_variant
#undef mtype_data_match

#undef HKEY

#define mtype_data_equal        IPSET_TOKEN(MTYPE, _data_equal)
#ifdef IP_SET_HASH_WITH_NETS
#define mtype_do_data_match     IPSET_TOKEN(MTYPE, _do_data_match)
#else
#define mtype_do_data_match(d)  1
#endif
#define mtype_data_set_flags    IPSET_TOKEN(MTYPE, _data_set_flags)
#define mtype_data_reset_elem   IPSET_TOKEN(MTYPE, _data_reset_elem)
#define mtype_data_reset_flags  IPSET_TOKEN(MTYPE, _data_reset_flags)
#define mtype_data_netmask      IPSET_TOKEN(MTYPE, _data_netmask)
#define mtype_data_list         IPSET_TOKEN(MTYPE, _data_list)
#define mtype_data_next         IPSET_TOKEN(MTYPE, _data_next)
#define mtype_elem              IPSET_TOKEN(MTYPE, _elem)
#define mtype_ahash_destroy     IPSET_TOKEN(MTYPE, _ahash_destroy)
#define mtype_ext_cleanup       IPSET_TOKEN(MTYPE, _ext_cleanup)
#define mtype_add_cidr          IPSET_TOKEN(MTYPE, _add_cidr)
#define mtype_del_cidr          IPSET_TOKEN(MTYPE, _del_cidr)
#define mtype_ahash_memsize     IPSET_TOKEN(MTYPE, _ahash_memsize)
#define mtype_flush             IPSET_TOKEN(MTYPE, _flush)
#define mtype_destroy           IPSET_TOKEN(MTYPE, _destroy)
#define mtype_gc_init           IPSET_TOKEN(MTYPE, _gc_init)
#define mtype_same_set          IPSET_TOKEN(MTYPE, _same_set)
#define mtype_kadt              IPSET_TOKEN(MTYPE, _kadt)
#define mtype_uadt              IPSET_TOKEN(MTYPE, _uadt)
#define mtype                   MTYPE

#define mtype_add               IPSET_TOKEN(MTYPE, _add)
#define mtype_del               IPSET_TOKEN(MTYPE, _del)
#define mtype_test_cidrs        IPSET_TOKEN(MTYPE, _test_cidrs)
#define mtype_test              IPSET_TOKEN(MTYPE, _test)
#define mtype_expire            IPSET_TOKEN(MTYPE, _expire)
#define mtype_resize            IPSET_TOKEN(MTYPE, _resize)
#define mtype_head              IPSET_TOKEN(MTYPE, _head)
#define mtype_list              IPSET_TOKEN(MTYPE, _list)
#define mtype_gc                IPSET_TOKEN(MTYPE, _gc)
#define mtype_variant           IPSET_TOKEN(MTYPE, _variant)
#define mtype_data_match        IPSET_TOKEN(MTYPE, _data_match)

#ifndef HKEY_DATALEN
#define HKEY_DATALEN            sizeof(struct mtype_elem)
#endif

#define HKEY(data, initval, htable_bits)                        \
(jhash2((u32 *)(data), HKEY_DATALEN/sizeof(u32), initval)       \
        & jhash_mask(htable_bits))

#ifndef htype
#define htype                   HTYPE

/* The generic hash structure */
struct htype {
        struct htable __rcu *table; /* the hash table */
        u32 maxelem;            /* max elements in the hash */
        u32 elements;           /* current element (vs timeout) */
        u32 initval;            /* random jhash init value */
#ifdef IP_SET_HASH_WITH_MARKMASK
        u32 markmask;           /* markmask value for mark mask to store */
#endif
        struct timer_list gc;   /* garbage collection when timeout enabled */
        struct mtype_elem next; /* temporary storage for uadd */
#ifdef IP_SET_HASH_WITH_MULTI
        u8 ahash_max;           /* max elements in an array block */
#endif
#ifdef IP_SET_HASH_WITH_NETMASK
        u8 netmask;             /* netmask value for subnets to store */
#endif
#ifdef IP_SET_HASH_WITH_RBTREE
        struct rb_root rbtree;
#endif
#ifdef IP_SET_HASH_WITH_NETS
        struct net_prefixes nets[0]; /* book-keeping of prefixes */
#endif
};
#endif

#ifdef IP_SET_HASH_WITH_NETS
/* Network cidr size book keeping when the hash stores different
 * sized networks */
static void
mtype_add_cidr(struct htype *h, u8 cidr, u8 nets_length, u8 n)
{
        int i, j;

        /* Add in increasing prefix order, so larger cidr first */
        for (i = 0, j = -1; i < nets_length && h->nets[i].nets[n]; i++) {
                if (j != -1)
                        continue;
                else if (h->nets[i].cidr[n] < cidr)
                        j = i;
                else if (h->nets[i].cidr[n] == cidr) {
                        h->nets[i].nets[n]++;
                        return;
                }
        }
        if (j != -1) {
                for (; i > j; i--) {
                        h->nets[i].cidr[n] = h->nets[i - 1].cidr[n];
                        h->nets[i].nets[n] = h->nets[i - 1].nets[n];
                }
        }
        h->nets[i].cidr[n] = cidr;
        h->nets[i].nets[n] = 1;
}

static void
mtype_del_cidr(struct htype *h, u8 cidr, u8 nets_length, u8 n)
{
        u8 i, j, net_end = nets_length - 1;

        for (i = 0; i < nets_length; i++) {
                if (h->nets[i].cidr[n] != cidr)
                        continue;
                if (h->nets[i].nets[n] > 1 || i == net_end ||
                    h->nets[i + 1].nets[n] == 0) {
                        h->nets[i].nets[n]--;
                        return;
                }
                for (j = i; j < net_end && h->nets[j].nets[n]; j++) {
                        h->nets[j].cidr[n] = h->nets[j + 1].cidr[n];
                        h->nets[j].nets[n] = h->nets[j + 1].nets[n];
                }
                h->nets[j].nets[n] = 0;
                return;
        }
}
#endif

/* Calculate the actual memory size of the set data */
static size_t
mtype_ahash_memsize(const struct htype *h, const struct htable *t,
                    u8 nets_length, size_t dsize)
{
        u32 i;
        size_t memsize = sizeof(*h)
                         + sizeof(*t)
#ifdef IP_SET_HASH_WITH_NETS
                         + sizeof(struct net_prefixes) * nets_length
#endif
                         + jhash_size(t->htable_bits) * sizeof(struct hbucket);

        for (i = 0; i < jhash_size(t->htable_bits); i++)
                memsize += t->bucket[i].size * dsize;

        return memsize;
}

/* Get the ith element from the array block n */
#define ahash_data(n, i, dsize) \
        ((struct mtype_elem *)((n)->value + ((i) * (dsize))))

static void
mtype_ext_cleanup(struct ip_set *set, struct hbucket *n)
{
        int i;

        for (i = 0; i < n->pos; i++)
                ip_set_ext_destroy(set, ahash_data(n, i, set->dsize));
}

/* Flush a hash type of set: destroy all elements */
static void
mtype_flush(struct ip_set *set)
{
        struct htype *h = set->data;
        struct htable *t;
        struct hbucket *n;
        u32 i;

        t = rcu_dereference_bh_nfnl(h->table);
        for (i = 0; i < jhash_size(t->htable_bits); i++) {
                n = hbucket(t, i);
                if (n->size) {
                        if (set->extensions & IPSET_EXT_DESTROY)
                                mtype_ext_cleanup(set, n);
                        n->size = n->pos = 0;
                        /* FIXME: use slab cache */
                        kfree(n->value);
                }
        }
#ifdef IP_SET_HASH_WITH_NETS
        memset(h->nets, 0, sizeof(struct net_prefixes) * NLEN(set->family));
#endif
        h->elements = 0;
}

/* Destroy the hashtable part of the set */
static void
mtype_ahash_destroy(struct ip_set *set, struct htable *t, bool ext_destroy)
{
        struct hbucket *n;
        u32 i;

        for (i = 0; i < jhash_size(t->htable_bits); i++) {
                n = hbucket(t, i);
                if (n->size) {
                        if (set->extensions & IPSET_EXT_DESTROY && ext_destroy)
                                mtype_ext_cleanup(set, n);
                        /* FIXME: use slab cache */
                        kfree(n->value);
                }
        }

        ip_set_free(t);
}

/* Destroy a hash type of set */
static void
mtype_destroy(struct ip_set *set)
{
        struct htype *h = set->data;

        if (set->extensions & IPSET_EXT_TIMEOUT)
                del_timer_sync(&h->gc);

        mtype_ahash_destroy(set, rcu_dereference_bh_nfnl(h->table), true);
#ifdef IP_SET_HASH_WITH_RBTREE
        rbtree_destroy(&h->rbtree);
#endif
        kfree(h);

        set->data = NULL;
}

static void
mtype_gc_init(struct ip_set *set, void (*gc)(unsigned long ul_set))
{
        struct htype *h = set->data;

        init_timer(&h->gc);
        h->gc.data = (unsigned long) set;
        h->gc.function = gc;
        h->gc.expires = jiffies + IPSET_GC_PERIOD(set->timeout) * HZ;
        add_timer(&h->gc);
        pr_debug("gc initialized, run in every %u\n",
                 IPSET_GC_PERIOD(set->timeout));
}

static bool
mtype_same_set(const struct ip_set *a, const struct ip_set *b)
{
        const struct htype *x = a->data;
        const struct htype *y = b->data;

        /* Resizing changes htable_bits, so we ignore it */
        return x->maxelem == y->maxelem &&
               a->timeout == b->timeout &&
#ifdef IP_SET_HASH_WITH_NETMASK
               x->netmask == y->netmask &&
#endif
#ifdef IP_SET_HASH_WITH_MARKMASK
               x->markmask == y->markmask &&
#endif
               a->extensions == b->extensions;
}

/* Delete expired elements from the hashtable */
static void
mtype_expire(struct ip_set *set, struct htype *h, u8 nets_length, size_t dsize)
{
        struct htable *t;
        struct hbucket *n;
        struct mtype_elem *data;
        u32 i;
        int j;
#ifdef IP_SET_HASH_WITH_NETS
        u8 k;
#endif

        rcu_read_lock_bh();
        t = rcu_dereference_bh(h->table);
        for (i = 0; i < jhash_size(t->htable_bits); i++) {
                n = hbucket(t, i);
                for (j = 0; j < n->pos; j++) {
                        data = ahash_data(n, j, dsize);
                        if (ip_set_timeout_expired(ext_timeout(data, set))) {
                                pr_debug("expired %u/%u\n", i, j);
#ifdef IP_SET_HASH_WITH_NETS
                                for (k = 0; k < IPSET_NET_COUNT; k++)
                                        mtype_del_cidr(h, CIDR(data->cidr, k),
                                                       nets_length, k);
#endif
                                ip_set_ext_destroy(set, data);
                                if (j != n->pos - 1)
                                        /* Not last one */
                                        memcpy(data,
                                               ahash_data(n, n->pos - 1, dsize),
                                               dsize);
                                n->pos--;
                                h->elements--;
                        }
                }
                if (n->pos + AHASH_INIT_SIZE < n->size) {
                        void *tmp = kzalloc((n->size - AHASH_INIT_SIZE)
                                            * dsize,
                                            GFP_ATOMIC);
                        if (!tmp)
                                /* Still try to delete expired elements */
                                continue;
                        n->size -= AHASH_INIT_SIZE;
                        memcpy(tmp, n->value, n->size * dsize);
                        kfree(n->value);
                        n->value = tmp;
                }
        }
        rcu_read_unlock_bh();
}

static void
mtype_gc(unsigned long ul_set)
{
        struct ip_set *set = (struct ip_set *) ul_set;
        struct htype *h = set->data;

        pr_debug("called\n");
        write_lock_bh(&set->lock);
        mtype_expire(set, h, NLEN(set->family), set->dsize);
        write_unlock_bh(&set->lock);

        h->gc.expires = jiffies + IPSET_GC_PERIOD(set->timeout) * HZ;
        add_timer(&h->gc);
}

/* Resize a hash: create a new hash table with doubling the hashsize
 * and inserting the elements to it. Repeat until we succeed or
 * fail due to memory pressures. */
static int
mtype_resize(struct ip_set *set, bool retried)
{
        struct htype *h = set->data;
        struct htable *t, *orig = rcu_dereference_bh_nfnl(h->table);
        u8 htable_bits = orig->htable_bits;
#ifdef IP_SET_HASH_WITH_NETS
        u8 flags;
#endif
        struct mtype_elem *data;
        struct mtype_elem *d;
        struct hbucket *n, *m;
        u32 i, j;
        int ret;

        /* Try to cleanup once */
        if (SET_WITH_TIMEOUT(set) && !retried) {
                i = h->elements;
                write_lock_bh(&set->lock);
                mtype_expire(set, set->data, NLEN(set->family), set->dsize);
                write_unlock_bh(&set->lock);
                if (h->elements < i)
                        return 0;
        }

retry:
        ret = 0;
        htable_bits++;
        pr_debug("attempt to resize set %s from %u to %u, t %p\n",
                 set->name, orig->htable_bits, htable_bits, orig);
        if (!htable_bits) {
                /* In case we have plenty of memory :-) */
                pr_warning("Cannot increase the hashsize of set %s further\n",
                           set->name);
                return -IPSET_ERR_HASH_FULL;
        }
        t = ip_set_alloc(sizeof(*t)
                         + jhash_size(htable_bits) * sizeof(struct hbucket));
        if (!t)
                return -ENOMEM;
        t->htable_bits = htable_bits;

        read_lock_bh(&set->lock);
        for (i = 0; i < jhash_size(orig->htable_bits); i++) {
                n = hbucket(orig, i);
                for (j = 0; j < n->pos; j++) {
                        data = ahash_data(n, j, set->dsize);
#ifdef IP_SET_HASH_WITH_NETS
                        flags = 0;
                        mtype_data_reset_flags(data, &flags);
#endif
                        m = hbucket(t, HKEY(data, h->initval, htable_bits));
                        ret = hbucket_elem_add(m, AHASH_MAX(h), set->dsize);
                        if (ret < 0) {
#ifdef IP_SET_HASH_WITH_NETS
                                mtype_data_reset_flags(data, &flags);
#endif
                                read_unlock_bh(&set->lock);
                                mtype_ahash_destroy(set, t, false);
                                if (ret == -EAGAIN)
                                        goto retry;
                                return ret;
                        }
                        d = ahash_data(m, m->pos++, set->dsize);
                        memcpy(d, data, set->dsize);
#ifdef IP_SET_HASH_WITH_NETS
                        mtype_data_reset_flags(d, &flags);
#endif
                }
        }

        rcu_assign_pointer(h->table, t);
        read_unlock_bh(&set->lock);

        /* Give time to other readers of the set */
        synchronize_rcu_bh();

        pr_debug("set %s resized from %u (%p) to %u (%p)\n", set->name,
                 orig->htable_bits, orig, t->htable_bits, t);
        mtype_ahash_destroy(set, orig, false);

        return 0;
}

/* Add an element to a hash and update the internal counters when succeeded,
 * otherwise report the proper error code. */
static int
mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
          struct ip_set_ext *mext, u32 flags)
{
        struct htype *h = set->data;
        struct htable *t;
        const struct mtype_elem *d = value;
        struct mtype_elem *data;
        struct hbucket *n;
        int i, ret = 0;
        int j = AHASH_MAX(h) + 1;
        bool flag_exist = flags & IPSET_FLAG_EXIST;
        u32 key, multi = 0;

        if (h->elements >= h->maxelem && SET_WITH_FORCEADD(set)) {
                rcu_read_lock_bh();
                t = rcu_dereference_bh(h->table);
                key = HKEY(value, h->initval, t->htable_bits);
                n = hbucket(t,key);
                if (n->pos) {
                        /* Choosing the first entry in the array to replace */
                        j = 0;
                        goto reuse_slot;
                }
                rcu_read_unlock_bh();
        }
        if (SET_WITH_TIMEOUT(set) && h->elements >= h->maxelem)
                /* FIXME: when set is full, we slow down here */
                mtype_expire(set, h, NLEN(set->family), set->dsize);

        if (h->elements >= h->maxelem) {
                if (net_ratelimit())
                        pr_warning("Set %s is full, maxelem %u reached\n",
                                   set->name, h->maxelem);
                return -IPSET_ERR_HASH_FULL;
        }

        rcu_read_lock_bh();
        t = rcu_dereference_bh(h->table);
        key = HKEY(value, h->initval, t->htable_bits);
        n = hbucket(t, key);
        for (i = 0; i < n->pos; i++) {
                data = ahash_data(n, i, set->dsize);
                if (mtype_data_equal(data, d, &multi)) {
                        if (flag_exist ||
                            (SET_WITH_TIMEOUT(set) &&
                             ip_set_timeout_expired(ext_timeout(data, set)))) {
                                /* Just the extensions could be overwritten */
                                j = i;
                                goto reuse_slot;
                        } else {
                                ret = -IPSET_ERR_EXIST;
                                goto out;
                        }
                }
                /* Reuse first timed out entry */
                if (SET_WITH_TIMEOUT(set) &&
                    ip_set_timeout_expired(ext_timeout(data, set)) &&
                    j != AHASH_MAX(h) + 1)
                        j = i;
        }
reuse_slot:
        if (j != AHASH_MAX(h) + 1) {
                /* Fill out reused slot */
                data = ahash_data(n, j, set->dsize);
#ifdef IP_SET_HASH_WITH_NETS
                for (i = 0; i < IPSET_NET_COUNT; i++) {
                        mtype_del_cidr(h, CIDR(data->cidr, i),
                                       NLEN(set->family), i);
                        mtype_add_cidr(h, CIDR(d->cidr, i),
                                       NLEN(set->family), i);
                }
#endif
                ip_set_ext_destroy(set, data);
        } else {
                /* Use/create a new slot */
                TUNE_AHASH_MAX(h, multi);
                ret = hbucket_elem_add(n, AHASH_MAX(h), set->dsize);
                if (ret != 0) {
                        if (ret == -EAGAIN)
                                mtype_data_next(&h->next, d);
                        goto out;
                }
                data = ahash_data(n, n->pos++, set->dsize);
#ifdef IP_SET_HASH_WITH_NETS
                for (i = 0; i < IPSET_NET_COUNT; i++)
                        mtype_add_cidr(h, CIDR(d->cidr, i), NLEN(set->family),
                                       i);
#endif
                h->elements++;
        }
        memcpy(data, d, sizeof(struct mtype_elem));
#ifdef IP_SET_HASH_WITH_NETS
        mtype_data_set_flags(data, flags);
#endif
        if (SET_WITH_TIMEOUT(set))
                ip_set_timeout_set(ext_timeout(data, set), ext->timeout);
        if (SET_WITH_COUNTER(set))
                ip_set_init_counter(ext_counter(data, set), ext);
        if (SET_WITH_COMMENT(set))
                ip_set_init_comment(ext_comment(data, set), ext);

out:
        rcu_read_unlock_bh();
        return ret;
}

/* Delete an element from the hash: swap it with the last element
 * and free up space if possible.
 */
static int
mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
          struct ip_set_ext *mext, u32 flags)
{
        struct htype *h = set->data;
        struct htable *t;
        const struct mtype_elem *d = value;
        struct mtype_elem *data;
        struct hbucket *n;
        int i, ret = -IPSET_ERR_EXIST;
#ifdef IP_SET_HASH_WITH_NETS
        u8 j;
#endif
        u32 key, multi = 0;

        rcu_read_lock_bh();
        t = rcu_dereference_bh(h->table);
        key = HKEY(value, h->initval, t->htable_bits);
        n = hbucket(t, key);
        for (i = 0; i < n->pos; i++) {
                data = ahash_data(n, i, set->dsize);
                if (!mtype_data_equal(data, d, &multi))
                        continue;
                if (SET_WITH_TIMEOUT(set) &&
                    ip_set_timeout_expired(ext_timeout(data, set)))
                        goto out;
                if (i != n->pos - 1)
                        /* Not last one */
                        memcpy(data, ahash_data(n, n->pos - 1, set->dsize),
                               set->dsize);

                n->pos--;
                h->elements--;
#ifdef IP_SET_HASH_WITH_NETS
                for (j = 0; j < IPSET_NET_COUNT; j++)
                        mtype_del_cidr(h, CIDR(d->cidr, j), NLEN(set->family),
                                       j);
#endif
                ip_set_ext_destroy(set, data);
                if (n->pos + AHASH_INIT_SIZE < n->size) {
                        void *tmp = kzalloc((n->size - AHASH_INIT_SIZE)
                                            * set->dsize,
                                            GFP_ATOMIC);
                        if (!tmp) {
                                ret = 0;
                                goto out;
                        }
                        n->size -= AHASH_INIT_SIZE;
                        memcpy(tmp, n->value, n->size * set->dsize);
                        kfree(n->value);
                        n->value = tmp;
                }
                ret = 0;
                goto out;
        }

out:
        rcu_read_unlock_bh();
        return ret;
}

static inline int
mtype_data_match(struct mtype_elem *data, const struct ip_set_ext *ext,
                 struct ip_set_ext *mext, struct ip_set *set, u32 flags)
{
        if (SET_WITH_COUNTER(set))
                ip_set_update_counter(ext_counter(data, set),
                                      ext, mext, flags);
        return mtype_do_data_match(data);
}

#ifdef IP_SET_HASH_WITH_NETS
/* Special test function which takes into account the different network
 * sizes added to the set */
static int
mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d,
                 const struct ip_set_ext *ext,
                 struct ip_set_ext *mext, u32 flags)
{
        struct htype *h = set->data;
        struct htable *t = rcu_dereference_bh(h->table);
        struct hbucket *n;
        struct mtype_elem *data;
#if IPSET_NET_COUNT == 2
        struct mtype_elem orig = *d;
        int i, j = 0, k;
#else
        int i, j = 0;
#endif
        u32 key, multi = 0;
        u8 nets_length = NLEN(set->family);

        pr_debug("test by nets\n");
        for (; j < nets_length && h->nets[j].nets[0] && !multi; j++) {
#if IPSET_NET_COUNT == 2
                mtype_data_reset_elem(d, &orig);
                mtype_data_netmask(d, h->nets[j].cidr[0], false);
                for (k = 0; k < nets_length && h->nets[k].nets[1] && !multi;
                     k++) {
                        mtype_data_netmask(d, h->nets[k].cidr[1], true);
#else
                mtype_data_netmask(d, h->nets[j].cidr[0]);
#endif
                key = HKEY(d, h->initval, t->htable_bits);
                n = hbucket(t, key);
                for (i = 0; i < n->pos; i++) {
                        data = ahash_data(n, i, set->dsize);
                        if (!mtype_data_equal(data, d, &multi))
                                continue;
                        if (SET_WITH_TIMEOUT(set)) {
                                if (!ip_set_timeout_expired(
                                                ext_timeout(data, set)))
                                        return mtype_data_match(data, ext,
                                                                mext, set,
                                                                flags);
#ifdef IP_SET_HASH_WITH_MULTI
                                multi = 0;
#endif
                        } else
                                return mtype_data_match(data, ext,
                                                        mext, set, flags);
                }
#if IPSET_NET_COUNT == 2
                }
#endif
        }
        return 0;
}
#endif

/* Test whether the element is added to the set */
static int
mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
           struct ip_set_ext *mext, u32 flags)
{
        struct htype *h = set->data;
        struct htable *t;
        struct mtype_elem *d = value;
        struct hbucket *n;
        struct mtype_elem *data;
        int i, ret = 0;
        u32 key, multi = 0;

        rcu_read_lock_bh();
        t = rcu_dereference_bh(h->table);
#ifdef IP_SET_HASH_WITH_NETS
        /* If we test an IP address and not a network address,
         * try all possible network sizes */
        for (i = 0; i < IPSET_NET_COUNT; i++)
                if (CIDR(d->cidr, i) != SET_HOST_MASK(set->family))
                        break;
        if (i == IPSET_NET_COUNT) {
                ret = mtype_test_cidrs(set, d, ext, mext, flags);
                goto out;
        }
#endif

        key = HKEY(d, h->initval, t->htable_bits);
        n = hbucket(t, key);
        for (i = 0; i < n->pos; i++) {
                data = ahash_data(n, i, set->dsize);
                if (mtype_data_equal(data, d, &multi) &&
                    !(SET_WITH_TIMEOUT(set) &&
                      ip_set_timeout_expired(ext_timeout(data, set)))) {
                        ret = mtype_data_match(data, ext, mext, set, flags);
                        goto out;
                }
        }
out:
        rcu_read_unlock_bh();
        return ret;
}

/* Reply a HEADER request: fill out the header part of the set */
static int
mtype_head(struct ip_set *set, struct sk_buff *skb)
{
        const struct htype *h = set->data;
        const struct htable *t;
        struct nlattr *nested;
        size_t memsize;

        t = rcu_dereference_bh_nfnl(h->table);
        memsize = mtype_ahash_memsize(h, t, NLEN(set->family), set->dsize);

        nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
        if (!nested)
                goto nla_put_failure;
        if (nla_put_net32(skb, IPSET_ATTR_HASHSIZE,
                          htonl(jhash_size(t->htable_bits))) ||
            nla_put_net32(skb, IPSET_ATTR_MAXELEM, htonl(h->maxelem)))
                goto nla_put_failure;
#ifdef IP_SET_HASH_WITH_NETMASK
        if (h->netmask != HOST_MASK &&
            nla_put_u8(skb, IPSET_ATTR_NETMASK, h->netmask))
                goto nla_put_failure;
#endif
#ifdef IP_SET_HASH_WITH_MARKMASK
        if (nla_put_u32(skb, IPSET_ATTR_MARKMASK, h->markmask))
                goto nla_put_failure;
#endif
        if (nla_put_net32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1)) ||
            nla_put_net32(skb, IPSET_ATTR_MEMSIZE, htonl(memsize)))
                goto nla_put_failure;
        if (unlikely(ip_set_put_flags(skb, set)))
                goto nla_put_failure;
        ipset_nest_end(skb, nested);

        return 0;
nla_put_failure:
        return -EMSGSIZE;
}

/* Reply a LIST/SAVE request: dump the elements of the specified set */
static int
mtype_list(const struct ip_set *set,
           struct sk_buff *skb, struct netlink_callback *cb)
{
        const struct htype *h = set->data;
        const struct htable *t = rcu_dereference_bh_nfnl(h->table);
        struct nlattr *atd, *nested;
        const struct hbucket *n;
        const struct mtype_elem *e;
        u32 first = cb->args[IPSET_CB_ARG0];
        /* We assume that one hash bucket fills into one page */
        void *incomplete;
        int i;

        atd = ipset_nest_start(skb, IPSET_ATTR_ADT);
        if (!atd)
                return -EMSGSIZE;
        pr_debug("list hash set %s\n", set->name);
        for (; cb->args[IPSET_CB_ARG0] < jhash_size(t->htable_bits);
             cb->args[IPSET_CB_ARG0]++) {
                incomplete = skb_tail_pointer(skb);
                n = hbucket(t, cb->args[IPSET_CB_ARG0]);
                pr_debug("cb->arg bucket: %lu, t %p n %p\n",
                         cb->args[IPSET_CB_ARG0], t, n);
                for (i = 0; i < n->pos; i++) {
                        e = ahash_data(n, i, set->dsize);
                        if (SET_WITH_TIMEOUT(set) &&
                            ip_set_timeout_expired(ext_timeout(e, set)))
                                continue;
                        pr_debug("list hash %lu hbucket %p i %u, data %p\n",
                                 cb->args[IPSET_CB_ARG0], n, i, e);
                        nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
                        if (!nested) {
                                if (cb->args[IPSET_CB_ARG0] == first) {
                                        nla_nest_cancel(skb, atd);
                                        return -EMSGSIZE;
                                } else
                                        goto nla_put_failure;
                        }
                        if (mtype_data_list(skb, e))
                                goto nla_put_failure;
                        if (ip_set_put_extensions(skb, set, e, true))
                                goto nla_put_failure;
                        ipset_nest_end(skb, nested);
                }
        }
        ipset_nest_end(skb, atd);
        /* Set listing finished */
        cb->args[IPSET_CB_ARG0] = 0;

        return 0;

nla_put_failure:
        nlmsg_trim(skb, incomplete);
        if (unlikely(first == cb->args[IPSET_CB_ARG0])) {
                pr_warning("Can't list set %s: one bucket does not fit into "
                           "a message. Please report it!\n", set->name);
                cb->args[IPSET_CB_ARG0] = 0;
                return -EMSGSIZE;
        }
        ipset_nest_end(skb, atd);
        return 0;
}

static int
IPSET_TOKEN(MTYPE, _kadt)(struct ip_set *set, const struct sk_buff *skb,
            const struct xt_action_param *par,
            enum ipset_adt adt, struct ip_set_adt_opt *opt);

static int
IPSET_TOKEN(MTYPE, _uadt)(struct ip_set *set, struct nlattr *tb[],
            enum ipset_adt adt, u32 *lineno, u32 flags, bool retried);

static const struct ip_set_type_variant mtype_variant = {
        .kadt   = mtype_kadt,
        .uadt   = mtype_uadt,
        .adt    = {
                [IPSET_ADD] = mtype_add,
                [IPSET_DEL] = mtype_del,
                [IPSET_TEST] = mtype_test,
        },
        .destroy = mtype_destroy,
        .flush  = mtype_flush,
        .head   = mtype_head,
        .list   = mtype_list,
        .resize = mtype_resize,
        .same_set = mtype_same_set,
};

#ifdef IP_SET_EMIT_CREATE
static int
IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
                            struct nlattr *tb[], u32 flags)
{
        u32 hashsize = IPSET_DEFAULT_HASHSIZE, maxelem = IPSET_DEFAULT_MAXELEM;
#ifdef IP_SET_HASH_WITH_MARKMASK
        u32 markmask;
#endif
        u8 hbits;
#ifdef IP_SET_HASH_WITH_NETMASK
        u8 netmask;
#endif
        size_t hsize;
        struct HTYPE *h;
        struct htable *t;

        if (!(set->family == NFPROTO_IPV4 || set->family == NFPROTO_IPV6))
                return -IPSET_ERR_INVALID_FAMILY;

#ifdef IP_SET_HASH_WITH_MARKMASK
        markmask = 0xffffffff;
#endif
#ifdef IP_SET_HASH_WITH_NETMASK
        netmask = set->family == NFPROTO_IPV4 ? 32 : 128;
        pr_debug("Create set %s with family %s\n",
                 set->name, set->family == NFPROTO_IPV4 ? "inet" : "inet6");
#endif

        if (unlikely(!ip_set_optattr_netorder(tb, IPSET_ATTR_HASHSIZE) ||
                     !ip_set_optattr_netorder(tb, IPSET_ATTR_MAXELEM) ||
#ifdef IP_SET_HASH_WITH_MARKMASK
                     !ip_set_optattr_netorder(tb, IPSET_ATTR_MARKMASK) ||
#endif
                     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT) ||
                     !ip_set_optattr_netorder(tb, IPSET_ATTR_CADT_FLAGS)))
                return -IPSET_ERR_PROTOCOL;

        if (tb[IPSET_ATTR_HASHSIZE]) {
                hashsize = ip_set_get_h32(tb[IPSET_ATTR_HASHSIZE]);
                if (hashsize < IPSET_MIMINAL_HASHSIZE)
                        hashsize = IPSET_MIMINAL_HASHSIZE;
        }

        if (tb[IPSET_ATTR_MAXELEM])
                maxelem = ip_set_get_h32(tb[IPSET_ATTR_MAXELEM]);

#ifdef IP_SET_HASH_WITH_NETMASK
        if (tb[IPSET_ATTR_NETMASK]) {
                netmask = nla_get_u8(tb[IPSET_ATTR_NETMASK]);

                if ((set->family == NFPROTO_IPV4 && netmask > 32) ||
                    (set->family == NFPROTO_IPV6 && netmask > 128) ||
                    netmask == 0)
                        return -IPSET_ERR_INVALID_NETMASK;
        }
#endif
#ifdef IP_SET_HASH_WITH_MARKMASK
        if (tb[IPSET_ATTR_MARKMASK]) {
                markmask = ntohl(nla_get_u32(tb[IPSET_ATTR_MARKMASK]));

                if ((markmask > 4294967295u) || markmask == 0)
                        return -IPSET_ERR_INVALID_MARKMASK;
        }
#endif

        hsize = sizeof(*h);
#ifdef IP_SET_HASH_WITH_NETS
        hsize += sizeof(struct net_prefixes) *
                (set->family == NFPROTO_IPV4 ? 32 : 128);
#endif
        h = kzalloc(hsize, GFP_KERNEL);
        if (!h)
                return -ENOMEM;

        h->maxelem = maxelem;
#ifdef IP_SET_HASH_WITH_NETMASK
        h->netmask = netmask;
#endif
#ifdef IP_SET_HASH_WITH_MARKMASK
        h->markmask = markmask;
#endif
        get_random_bytes(&h->initval, sizeof(h->initval));
        set->timeout = IPSET_NO_TIMEOUT;

        hbits = htable_bits(hashsize);
        hsize = htable_size(hbits);
        if (hsize == 0) {
                kfree(h);
                return -ENOMEM;
        }
        t = ip_set_alloc(hsize);
        if (!t) {
                kfree(h);
                return -ENOMEM;
        }
        t->htable_bits = hbits;
        rcu_assign_pointer(h->table, t);

        set->data = h;
        if (set->family == NFPROTO_IPV4) {
                set->variant = &IPSET_TOKEN(HTYPE, 4_variant);
                set->dsize = ip_set_elem_len(set, tb,
                                sizeof(struct IPSET_TOKEN(HTYPE, 4_elem)));
        } else {
                set->variant = &IPSET_TOKEN(HTYPE, 6_variant);
                set->dsize = ip_set_elem_len(set, tb,
                                sizeof(struct IPSET_TOKEN(HTYPE, 6_elem)));
        }
        if (tb[IPSET_ATTR_TIMEOUT]) {
                set->timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
                if (set->family == NFPROTO_IPV4)
                        IPSET_TOKEN(HTYPE, 4_gc_init)(set,
                                IPSET_TOKEN(HTYPE, 4_gc));
                else
                        IPSET_TOKEN(HTYPE, 6_gc_init)(set,
                                IPSET_TOKEN(HTYPE, 6_gc));
        }

        pr_debug("create %s hashsize %u (%u) maxelem %u: %p(%p)\n",
                 set->name, jhash_size(t->htable_bits),
                 t->htable_bits, h->maxelem, set->data, t);

        return 0;
}
#endif /* IP_SET_EMIT_CREATE */