ip_set_bitmap_ipmac.c

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/* Copyright (C) 2000-2002 Joakim Axelsson <[email protected]>
 *                         Patrick Schaaf <[email protected]>
 *             Martin Josefsson <[email protected]>
 * 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 bitmap:ip,mac type */

#include <linux/module.h>
#include <linux/ip.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/if_ether.h>
#include <linux/netlink.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <net/netlink.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_bitmap.h>

#define REVISION_MIN    0
#define REVISION_MAX    0

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

enum {
    MAC_EMPTY,      /* element is not set */
    MAC_FILLED,     /* element is set with MAC */
    MAC_UNSET,      /* element is set, without MAC */
};

/* Type structure */
struct bitmap_ipmac {
    void *members;      /* the set members */
    u32 first_ip;       /* host byte order, included in range */
    u32 last_ip;        /* host byte order, included in range */
    u32 timeout;        /* timeout value */
    struct timer_list gc;   /* garbage collector */
    size_t dsize;       /* size of element */
};

/* ADT structure for generic function args */
struct ipmac {
    u32 id;         /* id in array */
    unsigned char *ether;   /* ethernet address */
};

/* Member element without and with timeout */

struct ipmac_elem {
    unsigned char ether[ETH_ALEN];
    unsigned char match;
} __attribute__ ((aligned));

struct ipmac_telem {
    unsigned char ether[ETH_ALEN];
    unsigned char match;
    unsigned long timeout;
} __attribute__ ((aligned));

static inline void *
bitmap_ipmac_elem(const struct bitmap_ipmac *map, u32 id)
{
    return (void *)((char *)map->members + id * map->dsize);
}

static inline bool
bitmap_timeout(const struct bitmap_ipmac *map, u32 id)
{
    const struct ipmac_telem *elem = bitmap_ipmac_elem(map, id);

    return ip_set_timeout_test(elem->timeout);
}

static inline bool
bitmap_expired(const struct bitmap_ipmac *map, u32 id)
{
    const struct ipmac_telem *elem = bitmap_ipmac_elem(map, id);

    return ip_set_timeout_expired(elem->timeout);
}

static inline int
bitmap_ipmac_exist(const struct ipmac_telem *elem)
{
    return elem->match == MAC_UNSET ||
           (elem->match == MAC_FILLED &&
        !ip_set_timeout_expired(elem->timeout));
}

/* Base variant */

static int
bitmap_ipmac_test(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    const struct bitmap_ipmac *map = set->data;
    const struct ipmac *data = value;
    const struct ipmac_elem *elem = bitmap_ipmac_elem(map, data->id);

    switch (elem->match) {
    case MAC_UNSET:
        /* Trigger kernel to fill out the ethernet address */
        return -EAGAIN;
    case MAC_FILLED:
        return data->ether == NULL ||
               ether_addr_equal(data->ether, elem->ether);
    }
    return 0;
}

static int
bitmap_ipmac_add(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct bitmap_ipmac *map = set->data;
    const struct ipmac *data = value;
    struct ipmac_elem *elem = bitmap_ipmac_elem(map, data->id);

    switch (elem->match) {
    case MAC_UNSET:
        if (!data->ether)
            /* Already added without ethernet address */
            return -IPSET_ERR_EXIST;
        /* Fill the MAC address */
        memcpy(elem->ether, data->ether, ETH_ALEN);
        elem->match = MAC_FILLED;
        break;
    case MAC_FILLED:
        return -IPSET_ERR_EXIST;
    case MAC_EMPTY:
        if (data->ether) {
            memcpy(elem->ether, data->ether, ETH_ALEN);
            elem->match = MAC_FILLED;
        } else
            elem->match = MAC_UNSET;
    }

    return 0;
}

static int
bitmap_ipmac_del(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct bitmap_ipmac *map = set->data;
    const struct ipmac *data = value;
    struct ipmac_elem *elem = bitmap_ipmac_elem(map, data->id);

    if (elem->match == MAC_EMPTY)
        return -IPSET_ERR_EXIST;

    elem->match = MAC_EMPTY;

    return 0;
}

static int
bitmap_ipmac_list(const struct ip_set *set,
          struct sk_buff *skb, struct netlink_callback *cb)
{
    const struct bitmap_ipmac *map = set->data;
    const struct ipmac_elem *elem;
    struct nlattr *atd, *nested;
    u32 id, first = cb->args[2];
    u32 last = map->last_ip - map->first_ip;

    atd = ipset_nest_start(skb, IPSET_ATTR_ADT);
    if (!atd)
        return -EMSGSIZE;
    for (; cb->args[2] <= last; cb->args[2]++) {
        id = cb->args[2];
        elem = bitmap_ipmac_elem(map, id);
        if (elem->match == MAC_EMPTY)
            continue;
        nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
        if (!nested) {
            if (id == first) {
                nla_nest_cancel(skb, atd);
                return -EMSGSIZE;
            } else
                goto nla_put_failure;
        }
        if (nla_put_ipaddr4(skb, IPSET_ATTR_IP,
                    htonl(map->first_ip + id)) ||
            (elem->match == MAC_FILLED &&
             nla_put(skb, IPSET_ATTR_ETHER, ETH_ALEN,
                 elem->ether)))
            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:
    nla_nest_cancel(skb, nested);
    ipset_nest_end(skb, atd);
    if (unlikely(id == first)) {
        cb->args[2] = 0;
        return -EMSGSIZE;
    }
    return 0;
}

/* Timeout variant */

static int
bitmap_ipmac_ttest(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    const struct bitmap_ipmac *map = set->data;
    const struct ipmac *data = value;
    const struct ipmac_elem *elem = bitmap_ipmac_elem(map, data->id);

    switch (elem->match) {
    case MAC_UNSET:
        /* Trigger kernel to fill out the ethernet address */
        return -EAGAIN;
    case MAC_FILLED:
        return (data->ether == NULL ||
            ether_addr_equal(data->ether, elem->ether)) &&
               !bitmap_expired(map, data->id);
    }
    return 0;
}

static int
bitmap_ipmac_tadd(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct bitmap_ipmac *map = set->data;
    const struct ipmac *data = value;
    struct ipmac_telem *elem = bitmap_ipmac_elem(map, data->id);
    bool flag_exist = flags & IPSET_FLAG_EXIST;

    switch (elem->match) {
    case MAC_UNSET:
        if (!(data->ether || flag_exist))
            /* Already added without ethernet address */
            return -IPSET_ERR_EXIST;
        /* Fill the MAC address and activate the timer */
        memcpy(elem->ether, data->ether, ETH_ALEN);
        elem->match = MAC_FILLED;
        if (timeout == map->timeout)
            /* Timeout was not specified, get stored one */
            timeout = elem->timeout;
        elem->timeout = ip_set_timeout_set(timeout);
        break;
    case MAC_FILLED:
        if (!(bitmap_expired(map, data->id) || flag_exist))
            return -IPSET_ERR_EXIST;
        /* Fall through */
    case MAC_EMPTY:
        if (data->ether) {
            memcpy(elem->ether, data->ether, ETH_ALEN);
            elem->match = MAC_FILLED;
        } else
            elem->match = MAC_UNSET;
        /* If MAC is unset yet, we store plain timeout value
         * because the timer is not activated yet
         * and we can reuse it later when MAC is filled out,
         * possibly by the kernel */
        elem->timeout = data->ether ? ip_set_timeout_set(timeout)
                        : timeout;
        break;
    }

    return 0;
}

static int
bitmap_ipmac_tdel(struct ip_set *set, void *value, u32 timeout, u32 flags)
{
    struct bitmap_ipmac *map = set->data;
    const struct ipmac *data = value;
    struct ipmac_telem *elem = bitmap_ipmac_elem(map, data->id);

    if (elem->match == MAC_EMPTY || bitmap_expired(map, data->id))
        return -IPSET_ERR_EXIST;

    elem->match = MAC_EMPTY;

    return 0;
}

static int
bitmap_ipmac_tlist(const struct ip_set *set,
           struct sk_buff *skb, struct netlink_callback *cb)
{
    const struct bitmap_ipmac *map = set->data;
    const struct ipmac_telem *elem;
    struct nlattr *atd, *nested;
    u32 id, first = cb->args[2];
    u32 timeout, last = map->last_ip - map->first_ip;

    atd = ipset_nest_start(skb, IPSET_ATTR_ADT);
    if (!atd)
        return -EMSGSIZE;
    for (; cb->args[2] <= last; cb->args[2]++) {
        id = cb->args[2];
        elem = bitmap_ipmac_elem(map, id);
        if (!bitmap_ipmac_exist(elem))
            continue;
        nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
        if (!nested) {
            if (id == first) {
                nla_nest_cancel(skb, atd);
                return -EMSGSIZE;
            } else
                goto nla_put_failure;
        }
        if (nla_put_ipaddr4(skb, IPSET_ATTR_IP,
                    htonl(map->first_ip + id)) ||
            (elem->match == MAC_FILLED &&
             nla_put(skb, IPSET_ATTR_ETHER, ETH_ALEN,
                 elem->ether)))
            goto nla_put_failure;
        timeout = elem->match == MAC_UNSET ? elem->timeout
                : ip_set_timeout_get(elem->timeout);
        if (nla_put_net32(skb, IPSET_ATTR_TIMEOUT, htonl(timeout)))
            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:
    nla_nest_cancel(skb, nested);
    ipset_nest_end(skb, atd);
    return -EMSGSIZE;
}

static int
bitmap_ipmac_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)
{
    struct bitmap_ipmac *map = set->data;
    ipset_adtfn adtfn = set->variant->adt[adt];
    struct ipmac data;

    /* MAC can be src only */
    if (!(opt->flags & IPSET_DIM_TWO_SRC))
        return 0;

    data.id = ntohl(ip4addr(skb, opt->flags & IPSET_DIM_ONE_SRC));
    if (data.id < map->first_ip || data.id > map->last_ip)
        return -IPSET_ERR_BITMAP_RANGE;

    /* Backward compatibility: we don't check the second flag */
    if (skb_mac_header(skb) < skb->head ||
        (skb_mac_header(skb) + ETH_HLEN) > skb->data)
        return -EINVAL;

    data.id -= map->first_ip;
    data.ether = eth_hdr(skb)->h_source;

    return adtfn(set, &data, opt_timeout(opt, map), opt->cmdflags);
}

static int
bitmap_ipmac_uadt(struct ip_set *set, struct nlattr *tb[],
          enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
{
    const struct bitmap_ipmac *map = set->data;
    ipset_adtfn adtfn = set->variant->adt[adt];
    struct ipmac data;
    u32 timeout = map->timeout;
    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], &data.id);
    if (ret)
        return ret;

    if (data.id < map->first_ip || data.id > map->last_ip)
        return -IPSET_ERR_BITMAP_RANGE;

    if (tb[IPSET_ATTR_ETHER])
        data.ether = nla_data(tb[IPSET_ATTR_ETHER]);
    else
        data.ether = NULL;

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

    data.id -= map->first_ip;

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

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

static void
bitmap_ipmac_destroy(struct ip_set *set)
{
    struct bitmap_ipmac *map = set->data;

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

    ip_set_free(map->members);
    kfree(map);

    set->data = NULL;
}

static void
bitmap_ipmac_flush(struct ip_set *set)
{
    struct bitmap_ipmac *map = set->data;

    memset(map->members, 0,
           (map->last_ip - map->first_ip + 1) * map->dsize);
}

static int
bitmap_ipmac_head(struct ip_set *set, struct sk_buff *skb)
{
    const struct bitmap_ipmac *map = set->data;
    struct nlattr *nested;

    nested = ipset_nest_start(skb, IPSET_ATTR_DATA);
    if (!nested)
        goto nla_put_failure;
    if (nla_put_ipaddr4(skb, IPSET_ATTR_IP, htonl(map->first_ip)) ||
        nla_put_ipaddr4(skb, IPSET_ATTR_IP_TO, htonl(map->last_ip)) ||
        nla_put_net32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref - 1)) ||
        nla_put_net32(skb, IPSET_ATTR_MEMSIZE,
              htonl(sizeof(*map) +
                ((map->last_ip - map->first_ip + 1) *
                 map->dsize))) ||
        (with_timeout(map->timeout) &&
         nla_put_net32(skb, IPSET_ATTR_TIMEOUT, htonl(map->timeout))))
        goto nla_put_failure;
    ipset_nest_end(skb, nested);

    return 0;
nla_put_failure:
    return -EMSGSIZE;
}

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

    return x->first_ip == y->first_ip &&
           x->last_ip == y->last_ip &&
           x->timeout == y->timeout;
}

static const struct ip_set_type_variant bitmap_ipmac = {
    .kadt   = bitmap_ipmac_kadt,
    .uadt   = bitmap_ipmac_uadt,
    .adt    = {
        [IPSET_ADD] = bitmap_ipmac_add,
        [IPSET_DEL] = bitmap_ipmac_del,
        [IPSET_TEST] = bitmap_ipmac_test,
    },
    .destroy = bitmap_ipmac_destroy,
    .flush  = bitmap_ipmac_flush,
    .head   = bitmap_ipmac_head,
    .list   = bitmap_ipmac_list,
    .same_set = bitmap_ipmac_same_set,
};

static const struct ip_set_type_variant bitmap_tipmac = {
    .kadt   = bitmap_ipmac_kadt,
    .uadt   = bitmap_ipmac_uadt,
    .adt    = {
        [IPSET_ADD] = bitmap_ipmac_tadd,
        [IPSET_DEL] = bitmap_ipmac_tdel,
        [IPSET_TEST] = bitmap_ipmac_ttest,
    },
    .destroy = bitmap_ipmac_destroy,
    .flush  = bitmap_ipmac_flush,
    .head   = bitmap_ipmac_head,
    .list   = bitmap_ipmac_tlist,
    .same_set = bitmap_ipmac_same_set,
};

static void
bitmap_ipmac_gc(unsigned long ul_set)
{
    struct ip_set *set = (struct ip_set *) ul_set;
    struct bitmap_ipmac *map = set->data;
    struct ipmac_telem *elem;
    u32 id, last = map->last_ip - map->first_ip;

    /* We run parallel with other readers (test element)
     * but adding/deleting new entries is locked out */
    read_lock_bh(&set->lock);
    for (id = 0; id <= last; id++) {
        elem = bitmap_ipmac_elem(map, id);
        if (elem->match == MAC_FILLED &&
            ip_set_timeout_expired(elem->timeout))
            elem->match = MAC_EMPTY;
    }
    read_unlock_bh(&set->lock);

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

static void
bitmap_ipmac_gc_init(struct ip_set *set)
{
    struct bitmap_ipmac *map = set->data;

    init_timer(&map->gc);
    map->gc.data = (unsigned long) set;
    map->gc.function = bitmap_ipmac_gc;
    map->gc.expires = jiffies + IPSET_GC_PERIOD(map->timeout) * HZ;
    add_timer(&map->gc);
}

/* Create bitmap:ip,mac type of sets */

static bool
init_map_ipmac(struct ip_set *set, struct bitmap_ipmac *map,
           u32 first_ip, u32 last_ip)
{
    map->members = ip_set_alloc((last_ip - first_ip + 1) * map->dsize);
    if (!map->members)
        return false;
    map->first_ip = first_ip;
    map->last_ip = last_ip;
    map->timeout = IPSET_NO_TIMEOUT;

    set->data = map;
    set->family = NFPROTO_IPV4;

    return true;
}

static int
bitmap_ipmac_create(struct ip_set *set, struct nlattr *tb[],
            u32 flags)
{
    u32 first_ip, last_ip;
    u64 elements;
    struct bitmap_ipmac *map;
    int ret;

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

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

    if (tb[IPSET_ATTR_IP_TO]) {
        ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP_TO], &last_ip);
        if (ret)
            return ret;
        if (first_ip > last_ip) {
            u32 tmp = first_ip;

            first_ip = last_ip;
            last_ip = tmp;
        }
    } else if (tb[IPSET_ATTR_CIDR]) {
        u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);

        if (cidr >= 32)
            return -IPSET_ERR_INVALID_CIDR;
        ip_set_mask_from_to(first_ip, last_ip, cidr);
    } else
        return -IPSET_ERR_PROTOCOL;

    elements = (u64)last_ip - first_ip + 1;

    if (elements > IPSET_BITMAP_MAX_RANGE + 1)
        return -IPSET_ERR_BITMAP_RANGE_SIZE;

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

    if (tb[IPSET_ATTR_TIMEOUT]) {
        map->dsize = sizeof(struct ipmac_telem);

        if (!init_map_ipmac(set, map, first_ip, last_ip)) {
            kfree(map);
            return -ENOMEM;
        }

        map->timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);

        set->variant = &bitmap_tipmac;

        bitmap_ipmac_gc_init(set);
    } else {
        map->dsize = sizeof(struct ipmac_elem);

        if (!init_map_ipmac(set, map, first_ip, last_ip)) {
            kfree(map);
            return -ENOMEM;
        }
        set->variant = &bitmap_ipmac;

    }
    return 0;
}

static struct ip_set_type bitmap_ipmac_type = {
    .name       = "bitmap:ip,mac",
    .protocol   = IPSET_PROTOCOL,
    .features   = IPSET_TYPE_IP | IPSET_TYPE_MAC,
    .dimension  = IPSET_DIM_TWO,
    .family     = NFPROTO_IPV4,
    .revision_min   = REVISION_MIN,
    .revision_max   = REVISION_MAX,
    .create     = bitmap_ipmac_create,
    .create_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 },
    },
    .adt_policy = {
        [IPSET_ATTR_IP]     = { .type = NLA_NESTED },
        [IPSET_ATTR_ETHER]  = { .type = NLA_BINARY,
                        .len  = ETH_ALEN },
        [IPSET_ATTR_TIMEOUT]    = { .type = NLA_U32 },
        [IPSET_ATTR_LINENO] = { .type = NLA_U32 },
    },
    .me     = THIS_MODULE,
};

static int __init
bitmap_ipmac_init(void)
{
    return ip_set_type_register(&bitmap_ipmac_type);
}

static void __exit
bitmap_ipmac_fini(void)
{
    ip_set_type_unregister(&bitmap_ipmac_type);
}

module_init(bitmap_ipmac_init);
module_exit(bitmap_ipmac_fini);