// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2000-2002 Joakim Axelsson <gozem@linux.nu>
 *                         Patrick Schaaf <bof@bof.de>
 * Copyright (C) 2003-2013 Jozsef Kadlecsik <kadlec@netfilter.org>
 */

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

#include <linux/module.h>
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/netlink.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <net/netlink.h>
#include <net/tcp.h>

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

#define IPSET_TYPE_REV_MIN      0
/*                              1          Counter support added */
/*                              2          Comment support added */
#define IPSET_TYPE_REV_MAX      3       /* skbinfo support added */

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@netfilter.org>");
IP_SET_MODULE_DESC("bitmap:ip", IPSET_TYPE_REV_MIN, IPSET_TYPE_REV_MAX);
MODULE_ALIAS("ip_set_bitmap:ip");

#define MTYPE           bitmap_ip
#define HOST_MASK       32

/* Type structure */
struct bitmap_ip {
        unsigned long *members; /* the set members */
        u32 first_ip;           /* host byte order, included in range */
        u32 last_ip;            /* host byte order, included in range */
        u32 elements;           /* number of max elements in the set */
        u32 hosts;              /* number of hosts in a subnet */
        size_t memsize;         /* members size */
        u8 netmask;             /* subnet netmask */
        struct timer_list gc;   /* garbage collection */
        struct ip_set *set;     /* attached to this ip_set */
        unsigned char extensions[]      /* data extensions */
                __aligned(__alignof__(u64));
};

/* ADT structure for generic function args */
struct bitmap_ip_adt_elem {
        u16 id;
};

static u32
ip_to_id(const struct bitmap_ip *m, u32 ip)
{
        return ((ip & ip_set_hostmask(m->netmask)) - m->first_ip) / m->hosts;
}

/* Common functions */

static int
bitmap_ip_do_test(const struct bitmap_ip_adt_elem *e,
                  struct bitmap_ip *map, size_t dsize)
{
        return !!test_bit(e->id, map->members);
}

static int
bitmap_ip_gc_test(u16 id, const struct bitmap_ip *map, size_t dsize)
{
        return !!test_bit(id, map->members);
}

static int
bitmap_ip_do_add(const struct bitmap_ip_adt_elem *e, struct bitmap_ip *map,
                 u32 flags, size_t dsize)
{
        return !!test_bit(e->id, map->members);
}

static int
bitmap_ip_do_del(const struct bitmap_ip_adt_elem *e, struct bitmap_ip *map)
{
        return !test_and_clear_bit(e->id, map->members);
}

static int
bitmap_ip_do_list(struct sk_buff *skb, const struct bitmap_ip *map, u32 id,
                  size_t dsize)
{
        return nla_put_ipaddr4(skb, IPSET_ATTR_IP,
                        htonl(map->first_ip + id * map->hosts));
}

static int
bitmap_ip_do_head(struct sk_buff *skb, const struct bitmap_ip *map)
{
        return nla_put_ipaddr4(skb, IPSET_ATTR_IP, htonl(map->first_ip)) ||
               nla_put_ipaddr4(skb, IPSET_ATTR_IP_TO, htonl(map->last_ip)) ||
               (map->netmask != 32 &&
                nla_put_u8(skb, IPSET_ATTR_NETMASK, map->netmask));
}

static int
bitmap_ip_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)
{
        struct bitmap_ip *map = set->data;
        ipset_adtfn adtfn = set->variant->adt[adt];
        struct bitmap_ip_adt_elem e = { .id = 0 };
        struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);
        u32 ip;

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

        e.id = ip_to_id(map, ip);

        return adtfn(set, &e, &ext, &opt->ext, opt->cmdflags);
}

static int
bitmap_ip_uadt(struct ip_set *set, struct nlattr *tb[],
               enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
{
        struct bitmap_ip *map = set->data;
        ipset_adtfn adtfn = set->variant->adt[adt];
        u32 ip = 0, ip_to = 0;
        struct bitmap_ip_adt_elem e = { .id = 0 };
        struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
        int ret = 0;

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

        if (unlikely(!tb[IPSET_ATTR_IP]))
                return -IPSET_ERR_PROTOCOL;

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

        ret = ip_set_get_extensions(set, tb, &ext);
        if (ret)
                return ret;

        if (ip < map->first_ip || ip > map->last_ip)
                return -IPSET_ERR_BITMAP_RANGE;

        if (adt == IPSET_TEST) {
                e.id = ip_to_id(map, ip);
                return adtfn(set, &e, &ext, &ext, flags);
        }

        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 > HOST_MASK)
                        return -IPSET_ERR_INVALID_CIDR;
                ip_set_mask_from_to(ip, ip_to, cidr);
        } else {
                ip_to = ip;
        }

        if (ip < map->first_ip || ip_to > map->last_ip)
                return -IPSET_ERR_BITMAP_RANGE;

        for (; !before(ip_to, ip); ip += map->hosts) {
                e.id = ip_to_id(map, ip);
                ret = adtfn(set, &e, &ext, &ext, flags);

                if (ret && !ip_set_eexist(ret, flags))
                        return ret;

                ret = 0;
        }
        return ret;
}

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

        return x->first_ip == y->first_ip &&
               x->last_ip == y->last_ip &&
               x->netmask == y->netmask &&
               a->timeout == b->timeout &&
               a->extensions == b->extensions;
}

/* Plain variant */

struct bitmap_ip_elem {
};

#include "ip_set_bitmap_gen.h"

/* Create bitmap:ip type of sets */

static bool
init_map_ip(struct ip_set *set, struct bitmap_ip *map,
            u32 first_ip, u32 last_ip,
            u32 elements, u32 hosts, u8 netmask)
{
        map->members = bitmap_zalloc(elements, GFP_KERNEL | __GFP_NOWARN);
        if (!map->members)
                return false;
        map->first_ip = first_ip;
        map->last_ip = last_ip;
        map->elements = elements;
        map->hosts = hosts;
        map->netmask = netmask;
        set->timeout = IPSET_NO_TIMEOUT;

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

        return true;
}

static u32
range_to_mask(u32 from, u32 to, u8 *bits)
{
        u32 mask = 0xFFFFFFFE;

        *bits = 32;
        while (--(*bits) > 0 && mask && (to & mask) != from)
                mask <<= 1;

        return mask;
}

static int
bitmap_ip_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
                 u32 flags)
{
        struct bitmap_ip *map;
        u32 first_ip = 0, last_ip = 0, hosts;
        u64 elements;
        u8 netmask = 32;
        int ret;

        if (unlikely(!tb[IPSET_ATTR_IP] ||
                     !ip_set_optattr_netorder(tb, IPSET_ATTR_TIMEOUT) ||
                     !ip_set_optattr_netorder(tb, IPSET_ATTR_CADT_FLAGS)))
                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)
                        swap(first_ip, last_ip);
        } else if (tb[IPSET_ATTR_CIDR]) {
                u8 cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);

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

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

                if (netmask > HOST_MASK)
                        return -IPSET_ERR_INVALID_NETMASK;

                first_ip &= ip_set_hostmask(netmask);
                last_ip |= ~ip_set_hostmask(netmask);
        }

        if (netmask == 32) {
                hosts = 1;
                elements = (u64)last_ip - first_ip + 1;
        } else {
                u8 mask_bits;
                u32 mask;

                mask = range_to_mask(first_ip, last_ip, &mask_bits);

                if ((!mask && (first_ip || last_ip != 0xFFFFFFFF)) ||
                    netmask <= mask_bits)
                        return -IPSET_ERR_BITMAP_RANGE;

                pr_debug("mask_bits %u, netmask %u\n", mask_bits, netmask);
                hosts = 2U << (32 - netmask - 1);
                elements = 2UL << (netmask - mask_bits - 1);
        }
        if (elements > IPSET_BITMAP_MAX_RANGE + 1)
                return -IPSET_ERR_BITMAP_RANGE_SIZE;

        pr_debug("hosts %u, elements %llu\n",
                 hosts, (unsigned long long)elements);

        set->dsize = ip_set_elem_len(set, tb, 0, 0);
        map = ip_set_alloc(sizeof(*map) + elements * set->dsize);
        if (!map)
                return -ENOMEM;

        map->memsize = BITS_TO_LONGS(elements) * sizeof(unsigned long);
        set->variant = &bitmap_ip;
        if (!init_map_ip(set, map, first_ip, last_ip,
                         elements, hosts, netmask)) {
                ip_set_free(map);
                return -ENOMEM;
        }
        if (tb[IPSET_ATTR_TIMEOUT]) {
                set->timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
                bitmap_ip_gc_init(set, bitmap_ip_gc);
        }
        return 0;
}

static struct ip_set_type bitmap_ip_type __read_mostly = {
        .name           = "bitmap:ip",
        .protocol       = IPSET_PROTOCOL,
        .features       = IPSET_TYPE_IP,
        .dimension      = IPSET_DIM_ONE,
        .family         = NFPROTO_IPV4,
        .revision_min   = IPSET_TYPE_REV_MIN,
        .revision_max   = IPSET_TYPE_REV_MAX,
        .create         = bitmap_ip_create,
        .create_policy  = {
                [IPSET_ATTR_IP]         = { .type = NLA_NESTED },
                [IPSET_ATTR_IP_TO]      = { .type = NLA_NESTED },
                [IPSET_ATTR_CIDR]       = { .type = NLA_U8 },
                [IPSET_ATTR_NETMASK]    = { .type = NLA_U8  },
                [IPSET_ATTR_TIMEOUT]    = { .type = NLA_U32 },
                [IPSET_ATTR_CADT_FLAGS] = { .type = NLA_U32 },
        },
        .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 },
                [IPSET_ATTR_BYTES]      = { .type = NLA_U64 },
                [IPSET_ATTR_PACKETS]    = { .type = NLA_U64 },
                [IPSET_ATTR_COMMENT]    = { .type = NLA_NUL_STRING,
                                            .len  = IPSET_MAX_COMMENT_SIZE },
                [IPSET_ATTR_SKBMARK]    = { .type = NLA_U64 },
                [IPSET_ATTR_SKBPRIO]    = { .type = NLA_U32 },
                [IPSET_ATTR_SKBQUEUE]   = { .type = NLA_U16 },
        },
        .me             = THIS_MODULE,
};

static int __init
bitmap_ip_init(void)
{
        return ip_set_type_register(&bitmap_ip_type);
}

static void __exit
bitmap_ip_fini(void)
{
        rcu_barrier();
        ip_set_type_unregister(&bitmap_ip_type);
}

module_init(bitmap_ip_init);
module_exit(bitmap_ip_fini);