ip_set_ahash.h

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#ifndef _IP_SET_AHASH_H
#define _IP_SET_AHASH_H

#include <linux/rcupdate.h>
#include <linux/jhash.h>
#include <linux/netfilter/ipset/ip_set_timeout.h>

#define CONCAT(a, b, c)     a##b##c
#define TOKEN(a, b, c)      CONCAT(a, b, c)

#define type_pf_next        TOKEN(TYPE, PF, _elem)

/* 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]))

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

/* The generic ip_set hash structure */
struct ip_set_hash {
    struct htable *table;   /* the hash table */
    u32 maxelem;        /* max elements in the hash */
    u32 elements;       /* current element (vs timeout) */
    u32 initval;        /* random jhash init value */
    u32 timeout;        /* timeout value, if enabled */
    struct timer_list gc;   /* garbage collection when timeout enabled */
    struct type_pf_next 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 ip_set_hash_nets nets[0]; /* book-keeping of prefixes */
#endif
};

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;
}

#ifdef IP_SET_HASH_WITH_NETS
#ifdef IP_SET_HASH_WITH_NETS_PACKED
/* When cidr is packed with nomatch, cidr - 1 is stored in the entry */
#define CIDR(cidr)  (cidr + 1)
#else
#define CIDR(cidr)  (cidr)
#endif

#define SET_HOST_MASK(family)   (family == AF_INET ? 32 : 128)
#ifdef IP_SET_HASH_WITH_MULTI
#define NETS_LENGTH(family) (SET_HOST_MASK(family) + 1)
#else
#define NETS_LENGTH(family) SET_HOST_MASK(family)
#endif

/* Network cidr size book keeping when the hash stores different
 * sized networks */
static void
add_cidr(struct ip_set_hash *h, u8 cidr, u8 nets_length)
{
    int i, j;

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

static void
del_cidr(struct ip_set_hash *h, u8 cidr, u8 nets_length)
{
    u8 i, j;

    for (i = 0; i < nets_length - 1 && h->nets[i].cidr != cidr; i++)
        ;
    h->nets[i].nets--;

    if (h->nets[i].nets != 0)
        return;

    for (j = i; j < nets_length - 1 && h->nets[j].nets; j++) {
        h->nets[j].cidr = h->nets[j + 1].cidr;
        h->nets[j].nets = h->nets[j + 1].nets;
    }
}
#else
#define NETS_LENGTH(family)     0
#endif

/* Destroy the hashtable part of the set */
static void
ahash_destroy(struct htable *t)
{
    struct hbucket *n;
    u32 i;

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

    ip_set_free(t);
}

/* Calculate the actual memory size of the set data */
static size_t
ahash_memsize(const struct ip_set_hash *h, size_t dsize, u8 nets_length)
{
    u32 i;
    struct htable *t = h->table;
    size_t memsize = sizeof(*h)
             + sizeof(*t)
#ifdef IP_SET_HASH_WITH_NETS
             + sizeof(struct ip_set_hash_nets) * 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;
}

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

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

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

    if (with_timeout(h->timeout))
        del_timer_sync(&h->gc);

    ahash_destroy(h->table);
#ifdef IP_SET_HASH_WITH_RBTREE
    rbtree_destroy(&h->rbtree);
#endif
    kfree(h);

    set->data = NULL;
}

#endif /* _IP_SET_AHASH_H */

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

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

/* Type/family dependent function prototypes */

#define type_pf_data_equal  TOKEN(TYPE, PF, _data_equal)
#define type_pf_data_isnull TOKEN(TYPE, PF, _data_isnull)
#define type_pf_data_copy   TOKEN(TYPE, PF, _data_copy)
#define type_pf_data_zero_out   TOKEN(TYPE, PF, _data_zero_out)
#define type_pf_data_netmask    TOKEN(TYPE, PF, _data_netmask)
#define type_pf_data_list   TOKEN(TYPE, PF, _data_list)
#define type_pf_data_tlist  TOKEN(TYPE, PF, _data_tlist)
#define type_pf_data_next   TOKEN(TYPE, PF, _data_next)
#define type_pf_data_flags  TOKEN(TYPE, PF, _data_flags)
#ifdef IP_SET_HASH_WITH_NETS
#define type_pf_data_match  TOKEN(TYPE, PF, _data_match)
#else
#define type_pf_data_match(d)   1
#endif

#define type_pf_elem        TOKEN(TYPE, PF, _elem)
#define type_pf_telem       TOKEN(TYPE, PF, _telem)
#define type_pf_data_timeout    TOKEN(TYPE, PF, _data_timeout)
#define type_pf_data_expired    TOKEN(TYPE, PF, _data_expired)
#define type_pf_data_timeout_set TOKEN(TYPE, PF, _data_timeout_set)

#define type_pf_elem_add    TOKEN(TYPE, PF, _elem_add)
#define type_pf_add     TOKEN(TYPE, PF, _add)
#define type_pf_del     TOKEN(TYPE, PF, _del)
#define type_pf_test_cidrs  TOKEN(TYPE, PF, _test_cidrs)
#define type_pf_test        TOKEN(TYPE, PF, _test)

#define type_pf_elem_tadd   TOKEN(TYPE, PF, _elem_tadd)
#define type_pf_del_telem   TOKEN(TYPE, PF, _ahash_del_telem)
#define type_pf_expire      TOKEN(TYPE, PF, _expire)
#define type_pf_tadd        TOKEN(TYPE, PF, _tadd)
#define type_pf_tdel        TOKEN(TYPE, PF, _tdel)
#define type_pf_ttest_cidrs TOKEN(TYPE, PF, _ahash_ttest_cidrs)
#define type_pf_ttest       TOKEN(TYPE, PF, _ahash_ttest)

#define type_pf_resize      TOKEN(TYPE, PF, _resize)
#define type_pf_tresize     TOKEN(TYPE, PF, _tresize)
#define type_pf_flush       ip_set_hash_flush
#define type_pf_destroy     ip_set_hash_destroy
#define type_pf_head        TOKEN(TYPE, PF, _head)
#define type_pf_list        TOKEN(TYPE, PF, _list)
#define type_pf_tlist       TOKEN(TYPE, PF, _tlist)
#define type_pf_same_set    TOKEN(TYPE, PF, _same_set)
#define type_pf_kadt        TOKEN(TYPE, PF, _kadt)
#define type_pf_uadt        TOKEN(TYPE, PF, _uadt)
#define type_pf_gc      TOKEN(TYPE, PF, _gc)
#define type_pf_gc_init     TOKEN(TYPE, PF, _gc_init)
#define type_pf_variant     TOKEN(TYPE, PF, _variant)
#define type_pf_tvariant    TOKEN(TYPE, PF, _tvariant)

/* Flavour without timeout */

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

/* Add an element to the hash table when resizing the set:
 * we spare the maintenance of the internal counters. */
static int
type_pf_elem_add(struct hbucket *n, const struct type_pf_elem *value,
         u8 ahash_max, u32 cadt_flags)
{
    struct type_pf_elem *data;

    if (n->pos >= n->size) {
        void *tmp;

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

        tmp = kzalloc((n->size + AHASH_INIT_SIZE)
                  * sizeof(struct type_pf_elem),
                  GFP_ATOMIC);
        if (!tmp)
            return -ENOMEM;
        if (n->size) {
            memcpy(tmp, n->value,
                   sizeof(struct type_pf_elem) * n->size);
            kfree(n->value);
        }
        n->value = tmp;
        n->size += AHASH_INIT_SIZE;
    }
    data = ahash_data(n, n->pos++);
    type_pf_data_copy(data, value);
#ifdef IP_SET_HASH_WITH_NETS
    /* Resizing won't overwrite stored flags */
    if (cadt_flags)
        type_pf_data_flags(data, cadt_flags);
#endif
    return 0;
}

/* 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
type_pf_resize(struct ip_set *set, bool retried)
{
    struct ip_set_hash *h = set->data;
    struct htable *t, *orig = h->table;
    u8 htable_bits = orig->htable_bits;
    const struct type_pf_elem *data;
    struct hbucket *n, *m;
    u32 i, j;
    int ret;

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);
            m = hbucket(t, HKEY(data, h->initval, htable_bits));
            ret = type_pf_elem_add(m, data, AHASH_MAX(h), 0);
            if (ret < 0) {
                read_unlock_bh(&set->lock);
                ahash_destroy(t);
                if (ret == -EAGAIN)
                    goto retry;
                return ret;
            }
        }
    }

    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);
    ahash_destroy(orig);

    return 0;
}

static inline void
type_pf_data_next(struct ip_set_hash *h, const struct type_pf_elem *d);

/* Add an element to a hash and update the internal counters when succeeded,
 * otherwise report the proper error code. */
static int
type_pf_add(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct ip_set_hash *h = set->data;
    struct htable *t;
    const struct type_pf_elem *d = value;
    struct hbucket *n;
    int i, ret = 0;
    u32 key, multi = 0;
    u32 cadt_flags = flags >> 16;

    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++)
        if (type_pf_data_equal(ahash_data(n, i), d, &multi)) {
#ifdef IP_SET_HASH_WITH_NETS
            if (flags & IPSET_FLAG_EXIST)
                /* Support overwriting just the flags */
                type_pf_data_flags(ahash_data(n, i),
                           cadt_flags);
#endif
            ret = -IPSET_ERR_EXIST;
            goto out;
        }
    TUNE_AHASH_MAX(h, multi);
    ret = type_pf_elem_add(n, value, AHASH_MAX(h), cadt_flags);
    if (ret != 0) {
        if (ret == -EAGAIN)
            type_pf_data_next(h, d);
        goto out;
    }

#ifdef IP_SET_HASH_WITH_NETS
    add_cidr(h, CIDR(d->cidr), NETS_LENGTH(set->family));
#endif
    h->elements++;
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
type_pf_del(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct ip_set_hash *h = set->data;
    struct htable *t = h->table;
    const struct type_pf_elem *d = value;
    struct hbucket *n;
    int i;
    struct type_pf_elem *data;
    u32 key, multi = 0;

    key = HKEY(value, h->initval, t->htable_bits);
    n = hbucket(t, key);
    for (i = 0; i < n->pos; i++) {
        data = ahash_data(n, i);
        if (!type_pf_data_equal(data, d, &multi))
            continue;
        if (i != n->pos - 1)
            /* Not last one */
            type_pf_data_copy(data, ahash_data(n, n->pos - 1));

        n->pos--;
        h->elements--;
#ifdef IP_SET_HASH_WITH_NETS
        del_cidr(h, CIDR(d->cidr), NETS_LENGTH(set->family));
#endif
        if (n->pos + AHASH_INIT_SIZE < n->size) {
            void *tmp = kzalloc((n->size - AHASH_INIT_SIZE)
                        * sizeof(struct type_pf_elem),
                        GFP_ATOMIC);
            if (!tmp)
                return 0;
            n->size -= AHASH_INIT_SIZE;
            memcpy(tmp, n->value,
                   n->size * sizeof(struct type_pf_elem));
            kfree(n->value);
            n->value = tmp;
        }
        return 0;
    }

    return -IPSET_ERR_EXIST;
}

#ifdef IP_SET_HASH_WITH_NETS

/* Special test function which takes into account the different network
 * sizes added to the set */
static int
type_pf_test_cidrs(struct ip_set *set, struct type_pf_elem *d, u32 timeout)
{
    struct ip_set_hash *h = set->data;
    struct htable *t = h->table;
    struct hbucket *n;
    const struct type_pf_elem *data;
    int i, j = 0;
    u32 key, multi = 0;
    u8 nets_length = NETS_LENGTH(set->family);

    pr_debug("test by nets\n");
    for (; j < nets_length && h->nets[j].nets && !multi; j++) {
        type_pf_data_netmask(d, h->nets[j].cidr);
        key = HKEY(d, h->initval, t->htable_bits);
        n = hbucket(t, key);
        for (i = 0; i < n->pos; i++) {
            data = ahash_data(n, i);
            if (type_pf_data_equal(data, d, &multi))
                return type_pf_data_match(data);
        }
    }
    return 0;
}
#endif

/* Test whether the element is added to the set */
static int
type_pf_test(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct ip_set_hash *h = set->data;
    struct htable *t = h->table;
    struct type_pf_elem *d = value;
    struct hbucket *n;
    const struct type_pf_elem *data;
    int i;
    u32 key, multi = 0;

#ifdef IP_SET_HASH_WITH_NETS
    /* If we test an IP address and not a network address,
     * try all possible network sizes */
    if (CIDR(d->cidr) == SET_HOST_MASK(set->family))
        return type_pf_test_cidrs(set, d, timeout);
#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);
        if (type_pf_data_equal(data, d, &multi))
            return type_pf_data_match(data);
    }
    return 0;
}

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

    read_lock_bh(&set->lock);
    memsize = ahash_memsize(h, with_timeout(h->timeout)
                    ? sizeof(struct type_pf_telem)
                    : sizeof(struct type_pf_elem),
                NETS_LENGTH(set->family));
    read_unlock_bh(&set->lock);

    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(h->table->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
    if (nla_put_net32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1)) ||
        nla_put_net32(skb, IPSET_ATTR_MEMSIZE, htonl(memsize)) ||
        (with_timeout(h->timeout) &&
         nla_put_net32(skb, IPSET_ATTR_TIMEOUT, htonl(h->timeout))))
        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
type_pf_list(const struct ip_set *set,
         struct sk_buff *skb, struct netlink_callback *cb)
{
    const struct ip_set_hash *h = set->data;
    const struct htable *t = h->table;
    struct nlattr *atd, *nested;
    const struct hbucket *n;
    const struct type_pf_elem *data;
    u32 first = cb->args[2];
    /* 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[2] < jhash_size(t->htable_bits); cb->args[2]++) {
        incomplete = skb_tail_pointer(skb);
        n = hbucket(t, cb->args[2]);
        pr_debug("cb->args[2]: %lu, t %p n %p\n", cb->args[2], t, n);
        for (i = 0; i < n->pos; i++) {
            data = ahash_data(n, i);
            pr_debug("list hash %lu hbucket %p i %u, data %p\n",
                 cb->args[2], n, i, data);
            nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
            if (!nested) {
                if (cb->args[2] == first) {
                    nla_nest_cancel(skb, atd);
                    return -EMSGSIZE;
                } else
                    goto nla_put_failure;
            }
            if (type_pf_data_list(skb, data))
                goto nla_put_failure;
            ipset_nest_end(skb, nested);
        }
    }
    ipset_nest_end(skb, atd);
    /* Set listing finished */
    cb->args[2] = 0;

    return 0;

nla_put_failure:
    nlmsg_trim(skb, incomplete);
    ipset_nest_end(skb, atd);
    if (unlikely(first == cb->args[2])) {
        pr_warning("Can't list set %s: one bucket does not fit into "
               "a message. Please report it!\n", set->name);
        cb->args[2] = 0;
        return -EMSGSIZE;
    }
    return 0;
}

static int
type_pf_kadt(struct ip_set *set, const struct sk_buff *skb,
         const struct xt_action_param *par,
         enum ipset_adt adt, const struct ip_set_adt_opt *opt);
static int
type_pf_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 type_pf_variant = {
    .kadt   = type_pf_kadt,
    .uadt   = type_pf_uadt,
    .adt    = {
        [IPSET_ADD] = type_pf_add,
        [IPSET_DEL] = type_pf_del,
        [IPSET_TEST] = type_pf_test,
    },
    .destroy = type_pf_destroy,
    .flush  = type_pf_flush,
    .head   = type_pf_head,
    .list   = type_pf_list,
    .resize = type_pf_resize,
    .same_set = type_pf_same_set,
};

/* Flavour with timeout support */

#define ahash_tdata(n, i) \
    (struct type_pf_elem *)((struct type_pf_telem *)((n)->value) + (i))

static inline u32
type_pf_data_timeout(const struct type_pf_elem *data)
{
    const struct type_pf_telem *tdata =
        (const struct type_pf_telem *) data;

    return tdata->timeout;
}

static inline bool
type_pf_data_expired(const struct type_pf_elem *data)
{
    const struct type_pf_telem *tdata =
        (const struct type_pf_telem *) data;

    return ip_set_timeout_expired(tdata->timeout);
}

static inline void
type_pf_data_timeout_set(struct type_pf_elem *data, u32 timeout)
{
    struct type_pf_telem *tdata = (struct type_pf_telem *) data;

    tdata->timeout = ip_set_timeout_set(timeout);
}

static int
type_pf_elem_tadd(struct hbucket *n, const struct type_pf_elem *value,
          u8 ahash_max, u32 cadt_flags, u32 timeout)
{
    struct type_pf_elem *data;

    if (n->pos >= n->size) {
        void *tmp;

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

        tmp = kzalloc((n->size + AHASH_INIT_SIZE)
                  * sizeof(struct type_pf_telem),
                  GFP_ATOMIC);
        if (!tmp)
            return -ENOMEM;
        if (n->size) {
            memcpy(tmp, n->value,
                   sizeof(struct type_pf_telem) * n->size);
            kfree(n->value);
        }
        n->value = tmp;
        n->size += AHASH_INIT_SIZE;
    }
    data = ahash_tdata(n, n->pos++);
    type_pf_data_copy(data, value);
    type_pf_data_timeout_set(data, timeout);
#ifdef IP_SET_HASH_WITH_NETS
    /* Resizing won't overwrite stored flags */
    if (cadt_flags)
        type_pf_data_flags(data, cadt_flags);
#endif
    return 0;
}

/* Delete expired elements from the hashtable */
static void
type_pf_expire(struct ip_set_hash *h, u8 nets_length)
{
    struct htable *t = h->table;
    struct hbucket *n;
    struct type_pf_elem *data;
    u32 i;
    int j;

    for (i = 0; i < jhash_size(t->htable_bits); i++) {
        n = hbucket(t, i);
        for (j = 0; j < n->pos; j++) {
            data = ahash_tdata(n, j);
            if (type_pf_data_expired(data)) {
                pr_debug("expired %u/%u\n", i, j);
#ifdef IP_SET_HASH_WITH_NETS
                del_cidr(h, CIDR(data->cidr), nets_length);
#endif
                if (j != n->pos - 1)
                    /* Not last one */
                    type_pf_data_copy(data,
                        ahash_tdata(n, n->pos - 1));
                n->pos--;
                h->elements--;
            }
        }
        if (n->pos + AHASH_INIT_SIZE < n->size) {
            void *tmp = kzalloc((n->size - AHASH_INIT_SIZE)
                        * sizeof(struct type_pf_telem),
                        GFP_ATOMIC);
            if (!tmp)
                /* Still try to delete expired elements */
                continue;
            n->size -= AHASH_INIT_SIZE;
            memcpy(tmp, n->value,
                   n->size * sizeof(struct type_pf_telem));
            kfree(n->value);
            n->value = tmp;
        }
    }
}

static int
type_pf_tresize(struct ip_set *set, bool retried)
{
    struct ip_set_hash *h = set->data;
    struct htable *t, *orig = h->table;
    u8 htable_bits = orig->htable_bits;
    const struct type_pf_elem *data;
    struct hbucket *n, *m;
    u32 i, j;
    int ret;

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

retry:
    ret = 0;
    htable_bits++;
    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_tdata(n, j);
            m = hbucket(t, HKEY(data, h->initval, htable_bits));
            ret = type_pf_elem_tadd(m, data, AHASH_MAX(h), 0,
                        type_pf_data_timeout(data));
            if (ret < 0) {
                read_unlock_bh(&set->lock);
                ahash_destroy(t);
                if (ret == -EAGAIN)
                    goto retry;
                return ret;
            }
        }
    }

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

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

    ahash_destroy(orig);

    return 0;
}

static int
type_pf_tadd(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct ip_set_hash *h = set->data;
    struct htable *t = h->table;
    const struct type_pf_elem *d = value;
    struct hbucket *n;
    struct type_pf_elem *data;
    int ret = 0, i, j = AHASH_MAX(h) + 1;
    bool flag_exist = flags & IPSET_FLAG_EXIST;
    u32 key, multi = 0;
    u32 cadt_flags = flags >> 16;

    if (h->elements >= h->maxelem)
        /* FIXME: when set is full, we slow down here */
        type_pf_expire(h, NETS_LENGTH(set->family));
    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(d, h->initval, t->htable_bits);
    n = hbucket(t, key);
    for (i = 0; i < n->pos; i++) {
        data = ahash_tdata(n, i);
        if (type_pf_data_equal(data, d, &multi)) {
            if (type_pf_data_expired(data) || flag_exist)
                /* Just timeout value may be updated */
                j = i;
            else {
                ret = -IPSET_ERR_EXIST;
                goto out;
            }
        } else if (j == AHASH_MAX(h) + 1 &&
               type_pf_data_expired(data))
            j = i;
    }
    if (j != AHASH_MAX(h) + 1) {
        data = ahash_tdata(n, j);
#ifdef IP_SET_HASH_WITH_NETS
        del_cidr(h, CIDR(data->cidr), NETS_LENGTH(set->family));
        add_cidr(h, CIDR(d->cidr), NETS_LENGTH(set->family));
#endif
        type_pf_data_copy(data, d);
        type_pf_data_timeout_set(data, timeout);
#ifdef IP_SET_HASH_WITH_NETS
        type_pf_data_flags(data, cadt_flags);
#endif
        goto out;
    }
    TUNE_AHASH_MAX(h, multi);
    ret = type_pf_elem_tadd(n, d, AHASH_MAX(h), cadt_flags, timeout);
    if (ret != 0) {
        if (ret == -EAGAIN)
            type_pf_data_next(h, d);
        goto out;
    }

#ifdef IP_SET_HASH_WITH_NETS
    add_cidr(h, CIDR(d->cidr), NETS_LENGTH(set->family));
#endif
    h->elements++;
out:
    rcu_read_unlock_bh();
    return ret;
}

static int
type_pf_tdel(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct ip_set_hash *h = set->data;
    struct htable *t = h->table;
    const struct type_pf_elem *d = value;
    struct hbucket *n;
    int i;
    struct type_pf_elem *data;
    u32 key, multi = 0;

    key = HKEY(value, h->initval, t->htable_bits);
    n = hbucket(t, key);
    for (i = 0; i < n->pos; i++) {
        data = ahash_tdata(n, i);
        if (!type_pf_data_equal(data, d, &multi))
            continue;
        if (type_pf_data_expired(data))
            return -IPSET_ERR_EXIST;
        if (i != n->pos - 1)
            /* Not last one */
            type_pf_data_copy(data, ahash_tdata(n, n->pos - 1));

        n->pos--;
        h->elements--;
#ifdef IP_SET_HASH_WITH_NETS
        del_cidr(h, CIDR(d->cidr), NETS_LENGTH(set->family));
#endif
        if (n->pos + AHASH_INIT_SIZE < n->size) {
            void *tmp = kzalloc((n->size - AHASH_INIT_SIZE)
                        * sizeof(struct type_pf_telem),
                        GFP_ATOMIC);
            if (!tmp)
                return 0;
            n->size -= AHASH_INIT_SIZE;
            memcpy(tmp, n->value,
                   n->size * sizeof(struct type_pf_telem));
            kfree(n->value);
            n->value = tmp;
        }
        return 0;
    }

    return -IPSET_ERR_EXIST;
}

#ifdef IP_SET_HASH_WITH_NETS
static int
type_pf_ttest_cidrs(struct ip_set *set, struct type_pf_elem *d, u32 timeout)
{
    struct ip_set_hash *h = set->data;
    struct htable *t = h->table;
    struct type_pf_elem *data;
    struct hbucket *n;
    int i, j = 0;
    u32 key, multi = 0;
    u8 nets_length = NETS_LENGTH(set->family);

    for (; j < nets_length && h->nets[j].nets && !multi; j++) {
        type_pf_data_netmask(d, h->nets[j].cidr);
        key = HKEY(d, h->initval, t->htable_bits);
        n = hbucket(t, key);
        for (i = 0; i < n->pos; i++) {
            data = ahash_tdata(n, i);
#ifdef IP_SET_HASH_WITH_MULTI
            if (type_pf_data_equal(data, d, &multi)) {
                if (!type_pf_data_expired(data))
                    return type_pf_data_match(data);
                multi = 0;
            }
#else
            if (type_pf_data_equal(data, d, &multi) &&
                !type_pf_data_expired(data))
                return type_pf_data_match(data);
#endif
        }
    }
    return 0;
}
#endif

static int
type_pf_ttest(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct ip_set_hash *h = set->data;
    struct htable *t = h->table;
    struct type_pf_elem *data, *d = value;
    struct hbucket *n;
    int i;
    u32 key, multi = 0;

#ifdef IP_SET_HASH_WITH_NETS
    if (CIDR(d->cidr) == SET_HOST_MASK(set->family))
        return type_pf_ttest_cidrs(set, d, timeout);
#endif
    key = HKEY(d, h->initval, t->htable_bits);
    n = hbucket(t, key);
    for (i = 0; i < n->pos; i++) {
        data = ahash_tdata(n, i);
        if (type_pf_data_equal(data, d, &multi) &&
            !type_pf_data_expired(data))
            return type_pf_data_match(data);
    }
    return 0;
}

static int
type_pf_tlist(const struct ip_set *set,
          struct sk_buff *skb, struct netlink_callback *cb)
{
    const struct ip_set_hash *h = set->data;
    const struct htable *t = h->table;
    struct nlattr *atd, *nested;
    const struct hbucket *n;
    const struct type_pf_elem *data;
    u32 first = cb->args[2];
    /* 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;
    for (; cb->args[2] < jhash_size(t->htable_bits); cb->args[2]++) {
        incomplete = skb_tail_pointer(skb);
        n = hbucket(t, cb->args[2]);
        for (i = 0; i < n->pos; i++) {
            data = ahash_tdata(n, i);
            pr_debug("list %p %u\n", n, i);
            if (type_pf_data_expired(data))
                continue;
            pr_debug("do list %p %u\n", n, i);
            nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
            if (!nested) {
                if (cb->args[2] == first) {
                    nla_nest_cancel(skb, atd);
                    return -EMSGSIZE;
                } else
                    goto nla_put_failure;
            }
            if (type_pf_data_tlist(skb, data))
                goto nla_put_failure;
            ipset_nest_end(skb, nested);
        }
    }
    ipset_nest_end(skb, atd);
    /* Set listing finished */
    cb->args[2] = 0;

    return 0;

nla_put_failure:
    nlmsg_trim(skb, incomplete);
    ipset_nest_end(skb, atd);
    if (unlikely(first == cb->args[2])) {
        pr_warning("Can't list set %s: one bucket does not fit into "
               "a message. Please report it!\n", set->name);
        cb->args[2] = 0;
        return -EMSGSIZE;
    }
    return 0;
}

static const struct ip_set_type_variant type_pf_tvariant = {
    .kadt   = type_pf_kadt,
    .uadt   = type_pf_uadt,
    .adt    = {
        [IPSET_ADD] = type_pf_tadd,
        [IPSET_DEL] = type_pf_tdel,
        [IPSET_TEST] = type_pf_ttest,
    },
    .destroy = type_pf_destroy,
    .flush  = type_pf_flush,
    .head   = type_pf_head,
    .list   = type_pf_tlist,
    .resize = type_pf_tresize,
    .same_set = type_pf_same_set,
};

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

    pr_debug("called\n");
    write_lock_bh(&set->lock);
    type_pf_expire(h, NETS_LENGTH(set->family));
    write_unlock_bh(&set->lock);

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

static void
type_pf_gc_init(struct ip_set *set)
{
    struct ip_set_hash *h = set->data;

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

#undef HKEY_DATALEN
#undef HKEY
#undef type_pf_data_equal
#undef type_pf_data_isnull
#undef type_pf_data_copy
#undef type_pf_data_zero_out
#undef type_pf_data_netmask
#undef type_pf_data_list
#undef type_pf_data_tlist
#undef type_pf_data_next
#undef type_pf_data_flags
#undef type_pf_data_match

#undef type_pf_elem
#undef type_pf_telem
#undef type_pf_data_timeout
#undef type_pf_data_expired
#undef type_pf_data_timeout_set

#undef type_pf_elem_add
#undef type_pf_add
#undef type_pf_del
#undef type_pf_test_cidrs
#undef type_pf_test

#undef type_pf_elem_tadd
#undef type_pf_del_telem
#undef type_pf_expire
#undef type_pf_tadd
#undef type_pf_tdel
#undef type_pf_ttest_cidrs
#undef type_pf_ttest

#undef type_pf_resize
#undef type_pf_tresize
#undef type_pf_flush
#undef type_pf_destroy
#undef type_pf_head
#undef type_pf_list
#undef type_pf_tlist
#undef type_pf_same_set
#undef type_pf_kadt
#undef type_pf_uadt
#undef type_pf_gc
#undef type_pf_gc_init
#undef type_pf_variant
#undef type_pf_tvariant