// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2000-2002 Joakim Axelsson <gozem@linux.nu>
 *                         Patrick Schaaf <bof@bof.de>
 *                         Martin Josefsson <gandalf@wlug.westbo.se>
 */

/* 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_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,mac", IPSET_TYPE_REV_MIN, IPSET_TYPE_REV_MAX);
MODULE_ALIAS("ip_set_bitmap:ip,mac");

#define MTYPE           bitmap_ipmac
#define HOST_MASK       32
#define IP_SET_BITMAP_STORED_TIMEOUT

enum {
        MAC_UNSET,              /* element is set, without MAC */
        MAC_FILLED,             /* element is set with MAC */
};

/* Type structure */
struct bitmap_ipmac {
        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 */
        size_t memsize;         /* members size */
        struct timer_list gc;   /* garbage collector */
        struct ip_set *set;     /* attached to this ip_set */
        unsigned char extensions[]      /* MAC + data extensions */
                __aligned(__alignof__(u64));
};

/* ADT structure for generic function args */
struct bitmap_ipmac_adt_elem {
        unsigned char ether[ETH_ALEN] __aligned(2);
        u16 id;
        u16 add_mac;
};

struct bitmap_ipmac_elem {
        unsigned char ether[ETH_ALEN];
        unsigned char filled;
} __aligned(__alignof__(u64));

static u32
ip_to_id(const struct bitmap_ipmac *m, u32 ip)
{
        return ip - m->first_ip;
}

#define get_elem(extensions, id, dsize)         \
        (struct bitmap_ipmac_elem *)(extensions + (id) * (dsize))

#define get_const_elem(extensions, id, dsize)   \
        (const struct bitmap_ipmac_elem *)(extensions + (id) * (dsize))

/* Common functions */

static int
bitmap_ipmac_do_test(const struct bitmap_ipmac_adt_elem *e,
                     const struct bitmap_ipmac *map, size_t dsize)
{
        const struct bitmap_ipmac_elem *elem;

        if (!test_bit(e->id, map->members))
                return 0;
        elem = get_const_elem(map->extensions, e->id, dsize);
        if (e->add_mac && elem->filled == MAC_FILLED)
                return ether_addr_equal(e->ether, elem->ether);
        /* Trigger kernel to fill out the ethernet address */
        return -EAGAIN;
}

static int
bitmap_ipmac_gc_test(u16 id, const struct bitmap_ipmac *map, size_t dsize)
{
        const struct bitmap_ipmac_elem *elem;

        if (!test_bit(id, map->members))
                return 0;
        elem = get_const_elem(map->extensions, id, dsize);
        /* Timer not started for the incomplete elements */
        return elem->filled == MAC_FILLED;
}

static int
bitmap_ipmac_is_filled(const struct bitmap_ipmac_elem *elem)
{
        return elem->filled == MAC_FILLED;
}

static int
bitmap_ipmac_add_timeout(unsigned long *timeout,
                         const struct bitmap_ipmac_adt_elem *e,
                         const struct ip_set_ext *ext, struct ip_set *set,
                         struct bitmap_ipmac *map, int mode)
{
        u32 t = ext->timeout;

        if (mode == IPSET_ADD_START_STORED_TIMEOUT) {
                if (t == set->timeout)
                        /* Timeout was not specified, get stored one */
                        t = *timeout;
                ip_set_timeout_set(timeout, t);
        } else {
                /* 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
                 */
                if (e->add_mac)
                        ip_set_timeout_set(timeout, t);
                else
                        *timeout = t;
        }
        return 0;
}

static int
bitmap_ipmac_do_add(const struct bitmap_ipmac_adt_elem *e,
                    struct bitmap_ipmac *map, u32 flags, size_t dsize)
{
        struct bitmap_ipmac_elem *elem;

        elem = get_elem(map->extensions, e->id, dsize);
        if (test_bit(e->id, map->members)) {
                if (elem->filled == MAC_FILLED) {
                        if (e->add_mac &&
                            (flags & IPSET_FLAG_EXIST) &&
                            !ether_addr_equal(e->ether, elem->ether)) {
                                /* memcpy isn't atomic */
                                clear_bit(e->id, map->members);
                                smp_mb__after_atomic();
                                ether_addr_copy(elem->ether, e->ether);
                        }
                        return IPSET_ADD_FAILED;
                } else if (!e->add_mac)
                        /* Already added without ethernet address */
                        return IPSET_ADD_FAILED;
                /* Fill the MAC address and trigger the timer activation */
                clear_bit(e->id, map->members);
                smp_mb__after_atomic();
                ether_addr_copy(elem->ether, e->ether);
                elem->filled = MAC_FILLED;
                return IPSET_ADD_START_STORED_TIMEOUT;
        } else if (e->add_mac) {
                /* We can store MAC too */
                ether_addr_copy(elem->ether, e->ether);
                elem->filled = MAC_FILLED;
                return 0;
        }
        elem->filled = MAC_UNSET;
        /* MAC is not stored yet, don't start timer */
        return IPSET_ADD_STORE_PLAIN_TIMEOUT;
}

static int
bitmap_ipmac_do_del(const struct bitmap_ipmac_adt_elem *e,
                    struct bitmap_ipmac *map)
{
        return !test_and_clear_bit(e->id, map->members);
}

static int
bitmap_ipmac_do_list(struct sk_buff *skb, const struct bitmap_ipmac *map,
                     u32 id, size_t dsize)
{
        const struct bitmap_ipmac_elem *elem =
                get_const_elem(map->extensions, id, dsize);

        return nla_put_ipaddr4(skb, IPSET_ATTR_IP,
                               htonl(map->first_ip + id)) ||
               (elem->filled == MAC_FILLED &&
                nla_put(skb, IPSET_ATTR_ETHER, ETH_ALEN, elem->ether));
}

static int
bitmap_ipmac_do_head(struct sk_buff *skb, const struct bitmap_ipmac *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));
}

static int
bitmap_ipmac_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_ipmac *map = set->data;
        ipset_adtfn adtfn = set->variant->adt[adt];
        struct bitmap_ipmac_adt_elem e = { .id = 0, .add_mac = 1 };
        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;

        /* 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;

        e.id = ip_to_id(map, ip);

        if (opt->flags & IPSET_DIM_TWO_SRC)
                ether_addr_copy(e.ether, eth_hdr(skb)->h_source);
        else
                ether_addr_copy(e.ether, eth_hdr(skb)->h_dest);

        if (is_zero_ether_addr(e.ether))
                return -EINVAL;

        return adtfn(set, &e, &ext, &opt->ext, 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 bitmap_ipmac_adt_elem e = { .id = 0 };
        struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
        u32 ip = 0;
        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;

        e.id = ip_to_id(map, ip);
        if (tb[IPSET_ATTR_ETHER]) {
                if (nla_len(tb[IPSET_ATTR_ETHER]) != ETH_ALEN)
                        return -IPSET_ERR_PROTOCOL;
                memcpy(e.ether, nla_data(tb[IPSET_ATTR_ETHER]), ETH_ALEN);
                e.add_mac = 1;
        }
        ret = adtfn(set, &e, &ext, &ext, flags);

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

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 &&
               a->timeout == b->timeout &&
               a->extensions == b->extensions;
}

/* Plain variant */

#include "ip_set_bitmap_gen.h"

/* 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, u32 elements)
{
        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;
        set->timeout = IPSET_NO_TIMEOUT;

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

        return true;
}

static int
bitmap_ipmac_create(struct net *net, struct ip_set *set, struct nlattr *tb[],
                    u32 flags)
{
        u32 first_ip = 0, last_ip = 0;
        u64 elements;
        struct bitmap_ipmac *map;
        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;
        }

        elements = (u64)last_ip - first_ip + 1;

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

        set->dsize = ip_set_elem_len(set, tb,
                                     sizeof(struct bitmap_ipmac_elem),
                                     __alignof__(struct bitmap_ipmac_elem));
        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_ipmac;
        if (!init_map_ipmac(set, map, first_ip, last_ip, elements)) {
                ip_set_free(map);
                return -ENOMEM;
        }
        if (tb[IPSET_ATTR_TIMEOUT]) {
                set->timeout = ip_set_timeout_uget(tb[IPSET_ATTR_TIMEOUT]);
                bitmap_ipmac_gc_init(set, bitmap_ipmac_gc);
        }
        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   = IPSET_TYPE_REV_MIN,
        .revision_max   = IPSET_TYPE_REV_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 },
                [IPSET_ATTR_CADT_FLAGS] = { .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 },
                [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_ipmac_init(void)
{
        return ip_set_type_register(&bitmap_ipmac_type);
}

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

module_init(bitmap_ipmac_init);
module_exit(bitmap_ipmac_fini);