ip_set_hash_ip.c

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/* Copyright (C) 2003-2011 Jozsef Kadlecsik <[email protected]>
 *
 * 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.
 */

/* Kernel module implementing an IP set type: the hash:ip type */

#include <linux/jhash.h>
#include <linux/module.h>
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/random.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/netlink.h>
#include <net/tcp.h>

#include <linux/netfilter.h>
#include <linux/netfilter/ipset/pfxlen.h>
#include <linux/netfilter/ipset/ip_set.h>
#include <linux/netfilter/ipset/ip_set_timeout.h>
#include <linux/netfilter/ipset/ip_set_hash.h>

#define REVISION_MIN    0
#define REVISION_MAX    0

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jozsef Kadlecsik <[email protected]>");
IP_SET_MODULE_DESC("hash:ip", REVISION_MIN, REVISION_MAX);
MODULE_ALIAS("ip_set_hash:ip");

/* Type specific function prefix */
#define TYPE        hash_ip

static bool
hash_ip_same_set(const struct ip_set *a, const struct ip_set *b);

#define hash_ip4_same_set   hash_ip_same_set
#define hash_ip6_same_set   hash_ip_same_set

/* The type variant functions: IPv4 */

/* Member elements without timeout */
struct hash_ip4_elem {
    __be32 ip;
};

/* Member elements with timeout support */
struct hash_ip4_telem {
    __be32 ip;
    unsigned long timeout;
};

static inline bool
hash_ip4_data_equal(const struct hash_ip4_elem *ip1,
            const struct hash_ip4_elem *ip2,
            u32 *multi)
{
    return ip1->ip == ip2->ip;
}

static inline bool
hash_ip4_data_isnull(const struct hash_ip4_elem *elem)
{
    return elem->ip == 0;
}

static inline void
hash_ip4_data_copy(struct hash_ip4_elem *dst, const struct hash_ip4_elem *src)
{
    dst->ip = src->ip;
}

/* Zero valued IP addresses cannot be stored */
static inline void
hash_ip4_data_zero_out(struct hash_ip4_elem *elem)
{
    elem->ip = 0;
}

static inline bool
hash_ip4_data_list(struct sk_buff *skb, const struct hash_ip4_elem *data)
{
    if (nla_put_ipaddr4(skb, IPSET_ATTR_IP, data->ip))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return 1;
}

static bool
hash_ip4_data_tlist(struct sk_buff *skb, const struct hash_ip4_elem *data)
{
    const struct hash_ip4_telem *tdata =
        (const struct hash_ip4_telem *)data;

    if (nla_put_ipaddr4(skb, IPSET_ATTR_IP, tdata->ip) ||
        nla_put_net32(skb, IPSET_ATTR_TIMEOUT,
              htonl(ip_set_timeout_get(tdata->timeout))))
        goto nla_put_failure;

    return 0;

nla_put_failure:
    return 1;
}

#define IP_SET_HASH_WITH_NETMASK
#define PF      4
#define HOST_MASK   32
#include <linux/netfilter/ipset/ip_set_ahash.h>

static inline void
hash_ip4_data_next(struct ip_set_hash *h, const struct hash_ip4_elem *d)
{
    h->next.ip = d->ip;
}

static int
hash_ip4_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)
{
    const struct ip_set_hash *h = set->data;
    ipset_adtfn adtfn = set->variant->adt[adt];
    __be32 ip;

    ip4addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &ip);
    ip &= ip_set_netmask(h->netmask);
    if (ip == 0)
        return -EINVAL;

    return adtfn(set, &ip, opt_timeout(opt, h), opt->cmdflags);
}

static int
hash_ip4_uadt(struct ip_set *set, struct nlattr *tb[],
          enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
{
    const struct ip_set_hash *h = set->data;
    ipset_adtfn adtfn = set->variant->adt[adt];
    u32 ip, ip_to, hosts, timeout = h->timeout;
    __be32 nip;
    int ret = 0;

    if (unlikely(!tb[IPSET_ATTR_IP] ||
             !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT)))
        return -IPSET_ERR_PROTOCOL;

    if (tb[IPSET_ATTR_LINENO])
        *lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);

    ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP], &ip);
    if (ret)
        return ret;

    ip &= ip_set_hostmask(h->netmask);

    if (tb[IPSET_ATTR_TIMEOUT]) {
        if (!with_timeout(h->timeout))
            return -IPSET_ERR_TIMEOUT;
        timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
    }

    if (adt == IPSET_TEST) {
        nip = htonl(ip);
        if (nip == 0)
            return -IPSET_ERR_HASH_ELEM;
        return adtfn(set, &nip, timeout, flags);
    }

    ip_to = ip;
    if (tb[IPSET_ATTR_IP_TO]) {
        ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP_TO], &ip_to);
        if (ret)
            return ret;
        if (ip > ip_to)
            swap(ip, ip_to);
    } else if (tb[IPSET_ATTR_CIDR]) {
        u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);

        if (!cidr || cidr > 32)
            return -IPSET_ERR_INVALID_CIDR;
        ip_set_mask_from_to(ip, ip_to, cidr);
    }

    hosts = h->netmask == 32 ? 1 : 2 << (32 - h->netmask - 1);

    if (retried)
        ip = ntohl(h->next.ip);
    for (; !before(ip_to, ip); ip += hosts) {
        nip = htonl(ip);
        if (nip == 0)
            return -IPSET_ERR_HASH_ELEM;
        ret = adtfn(set, &nip, timeout, flags);

        if (ret && !ip_set_eexist(ret, flags))
            return ret;
        else
            ret = 0;
    }
    return ret;
}

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

    /* Resizing changes htable_bits, so we ignore it */
    return x->maxelem == y->maxelem &&
           x->timeout == y->timeout &&
           x->netmask == y->netmask;
}

/* The type variant functions: IPv6 */

struct hash_ip6_elem {
    union nf_inet_addr ip;
};

struct hash_ip6_telem {
    union nf_inet_addr ip;
    unsigned long timeout;
};

static inline bool
hash_ip6_data_equal(const struct hash_ip6_elem *ip1,
            const struct hash_ip6_elem *ip2,
            u32 *multi)
{
    return ipv6_addr_cmp(&ip1->ip.in6, &ip2->ip.in6) == 0;
}

static inline bool
hash_ip6_data_isnull(const struct hash_ip6_elem *elem)
{
    return ipv6_addr_any(&elem->ip.in6);
}

static inline void
hash_ip6_data_copy(struct hash_ip6_elem *dst, const struct hash_ip6_elem *src)
{
    dst->ip.in6 = src->ip.in6;
}

static inline void
hash_ip6_data_zero_out(struct hash_ip6_elem *elem)
{
    ipv6_addr_set(&elem->ip.in6, 0, 0, 0, 0);
}

static inline void
ip6_netmask(union nf_inet_addr *ip, u8 prefix)
{
    ip->ip6[0] &= ip_set_netmask6(prefix)[0];
    ip->ip6[1] &= ip_set_netmask6(prefix)[1];
    ip->ip6[2] &= ip_set_netmask6(prefix)[2];
    ip->ip6[3] &= ip_set_netmask6(prefix)[3];
}

static bool
hash_ip6_data_list(struct sk_buff *skb, const struct hash_ip6_elem *data)
{
    if (nla_put_ipaddr6(skb, IPSET_ATTR_IP, &data->ip.in6))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return 1;
}

static bool
hash_ip6_data_tlist(struct sk_buff *skb, const struct hash_ip6_elem *data)
{
    const struct hash_ip6_telem *e =
        (const struct hash_ip6_telem *)data;

    if (nla_put_ipaddr6(skb, IPSET_ATTR_IP, &e->ip.in6) ||
        nla_put_net32(skb, IPSET_ATTR_TIMEOUT,
              htonl(ip_set_timeout_get(e->timeout))))
        goto nla_put_failure;
    return 0;

nla_put_failure:
    return 1;
}

#undef PF
#undef HOST_MASK

#define PF      6
#define HOST_MASK   128
#include <linux/netfilter/ipset/ip_set_ahash.h>

static inline void
hash_ip6_data_next(struct ip_set_hash *h, const struct hash_ip6_elem *d)
{
}

static int
hash_ip6_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)
{
    const struct ip_set_hash *h = set->data;
    ipset_adtfn adtfn = set->variant->adt[adt];
    union nf_inet_addr ip;

    ip6addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &ip.in6);
    ip6_netmask(&ip, h->netmask);
    if (ipv6_addr_any(&ip.in6))
        return -EINVAL;

    return adtfn(set, &ip, opt_timeout(opt, h), opt->cmdflags);
}

static const struct nla_policy hash_ip6_adt_policy[IPSET_ATTR_ADT_MAX + 1] = {
    [IPSET_ATTR_IP]     = { .type = NLA_NESTED },
    [IPSET_ATTR_TIMEOUT]    = { .type = NLA_U32 },
    [IPSET_ATTR_LINENO] = { .type = NLA_U32 },
};

static int
hash_ip6_uadt(struct ip_set *set, struct nlattr *tb[],
          enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
{
    const struct ip_set_hash *h = set->data;
    ipset_adtfn adtfn = set->variant->adt[adt];
    union nf_inet_addr ip;
    u32 timeout = h->timeout;
    int ret;

    if (unlikely(!tb[IPSET_ATTR_IP] ||
             !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT) ||
             tb[IPSET_ATTR_IP_TO] ||
             tb[IPSET_ATTR_CIDR]))
        return -IPSET_ERR_PROTOCOL;

    if (tb[IPSET_ATTR_LINENO])
        *lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);

    ret = ip_set_get_ipaddr6(tb[IPSET_ATTR_IP], &ip);
    if (ret)
        return ret;

    ip6_netmask(&ip, h->netmask);
    if (ipv6_addr_any(&ip.in6))
        return -IPSET_ERR_HASH_ELEM;

    if (tb[IPSET_ATTR_TIMEOUT]) {
        if (!with_timeout(h->timeout))
            return -IPSET_ERR_TIMEOUT;
        timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
    }

    ret = adtfn(set, &ip, timeout, flags);

    return ip_set_eexist(ret, flags) ? 0 : ret;
}

/* Create hash:ip type of sets */

static int
hash_ip_create(struct ip_set *set, struct nlattr *tb[], u32 flags)
{
    u32 hashsize = IPSET_DEFAULT_HASHSIZE, maxelem = IPSET_DEFAULT_MAXELEM;
    u8 netmask, hbits;
    size_t hsize;
    struct ip_set_hash *h;

    if (!(set->family == NFPROTO_IPV4 || set->family == NFPROTO_IPV6))
        return -IPSET_ERR_INVALID_FAMILY;
    netmask = set->family == NFPROTO_IPV4 ? 32 : 128;
    pr_debug("Create set %s with family %s\n",
         set->name, set->family == NFPROTO_IPV4 ? "inet" : "inet6");

    if (unlikely(!ip_set_optattr_netorder(tb, IPSET_ATTR_HASHSIZE) ||
             !ip_set_optattr_netorder(tb, IPSET_ATTR_MAXELEM) ||
             !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT)))
        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]);

    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;
    }

    h = kzalloc(sizeof(*h), GFP_KERNEL);
    if (!h)
        return -ENOMEM;

    h->maxelem = maxelem;
    h->netmask = netmask;
    get_random_bytes(&h->initval, sizeof(h->initval));
    h->timeout = IPSET_NO_TIMEOUT;

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

    set->data = h;

    if (tb[IPSET_ATTR_TIMEOUT]) {
        h->timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);

        set->variant = set->family == NFPROTO_IPV4
            ? &hash_ip4_tvariant : &hash_ip6_tvariant;

        if (set->family == NFPROTO_IPV4)
            hash_ip4_gc_init(set);
        else
            hash_ip6_gc_init(set);
    } else {
        set->variant = set->family == NFPROTO_IPV4
            ? &hash_ip4_variant : &hash_ip6_variant;
    }

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

    return 0;
}

static struct ip_set_type hash_ip_type __read_mostly = {
    .name       = "hash:ip",
    .protocol   = IPSET_PROTOCOL,
    .features   = IPSET_TYPE_IP,
    .dimension  = IPSET_DIM_ONE,
    .family     = NFPROTO_UNSPEC,
    .revision_min   = REVISION_MIN,
    .revision_max   = REVISION_MAX,
    .create     = hash_ip_create,
    .create_policy  = {
        [IPSET_ATTR_HASHSIZE]   = { .type = NLA_U32 },
        [IPSET_ATTR_MAXELEM]    = { .type = NLA_U32 },
        [IPSET_ATTR_PROBES] = { .type = NLA_U8 },
        [IPSET_ATTR_RESIZE] = { .type = NLA_U8  },
        [IPSET_ATTR_TIMEOUT]    = { .type = NLA_U32 },
        [IPSET_ATTR_NETMASK]    = { .type = NLA_U8  },
    },
    .adt_policy = {
        [IPSET_ATTR_IP]     = { .type = NLA_NESTED },
        [IPSET_ATTR_IP_TO]  = { .type = NLA_NESTED },
        [IPSET_ATTR_CIDR]   = { .type = NLA_U8 },
        [IPSET_ATTR_TIMEOUT]    = { .type = NLA_U32 },
        [IPSET_ATTR_LINENO] = { .type = NLA_U32 },
    },
    .me     = THIS_MODULE,
};

static int __init
hash_ip_init(void)
{
    return ip_set_type_register(&hash_ip_type);
}

static void __exit
hash_ip_fini(void)
{
    ip_set_type_unregister(&hash_ip_type);
}

module_init(hash_ip_init);
module_exit(hash_ip_fini);