// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2003-2013 Jozsef Kadlecsik <kadlec@netfilter.org> */

/* Kernel module implementing an IP set type: the hash:net 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 <linux/netfilter.h>
#include <linux/netfilter/ipset/pfxlen.h>
#include <linux/netfilter/ipset/ip_set.h>
#include <linux/netfilter/ipset/ip_set_hash.h>

#define IPSET_TYPE_REV_MIN      0
/*                              1    Range as input support for IPv4 added */
/*                              2    nomatch flag support added */
/*                              3    Counters support added */
/*                              4    Comments support added */
/*                              5    Forceadd support added */
/*                              6    skbinfo support added */
#define IPSET_TYPE_REV_MAX      7 /* bucketsize, initval support added */

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@netfilter.org>");
IP_SET_MODULE_DESC("hash:net", IPSET_TYPE_REV_MIN, IPSET_TYPE_REV_MAX);
MODULE_ALIAS("ip_set_hash:net");

/* Type specific function prefix */
#define HTYPE           hash_net
#define IP_SET_HASH_WITH_NETS

/* IPv4 variant */

/* Member elements  */
struct hash_net4_elem {
        __be32 ip;
        u16 padding0;
        u8 nomatch;
        u8 cidr;
};

/* Common functions */

static bool
hash_net4_data_equal(const struct hash_net4_elem *ip1,
                     const struct hash_net4_elem *ip2,
                     u32 *multi)
{
        return ip1->ip == ip2->ip &&
               ip1->cidr == ip2->cidr;
}

static int
hash_net4_do_data_match(const struct hash_net4_elem *elem)
{
        return elem->nomatch ? -ENOTEMPTY : 1;
}

static void
hash_net4_data_set_flags(struct hash_net4_elem *elem, u32 flags)
{
        elem->nomatch = (flags >> 16) & IPSET_FLAG_NOMATCH;
}

static void
hash_net4_data_reset_flags(struct hash_net4_elem *elem, u8 *flags)
{
        swap(*flags, elem->nomatch);
}

static void
hash_net4_data_netmask(struct hash_net4_elem *elem, u8 cidr)
{
        elem->ip &= ip_set_netmask(cidr);
        elem->cidr = cidr;
}

static bool
hash_net4_data_list(struct sk_buff *skb, const struct hash_net4_elem *data)
{
        u32 flags = data->nomatch ? IPSET_FLAG_NOMATCH : 0;

        if (nla_put_ipaddr4(skb, IPSET_ATTR_IP, data->ip) ||
            nla_put_u8(skb, IPSET_ATTR_CIDR, data->cidr) ||
            (flags &&
             nla_put_net32(skb, IPSET_ATTR_CADT_FLAGS, htonl(flags))))
                goto nla_put_failure;
        return false;

nla_put_failure:
        return true;
}

static void
hash_net4_data_next(struct hash_net4_elem *next,
                    const struct hash_net4_elem *d)
{
        next->ip = d->ip;
}

#define MTYPE           hash_net4
#define HOST_MASK       32
#include "ip_set_hash_gen.h"

static int
hash_net4_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)
{
        const struct hash_net4 *h = set->data;
        ipset_adtfn adtfn = set->variant->adt[adt];
        struct hash_net4_elem e = {
                .cidr = INIT_CIDR(h->nets[0].cidr[0], HOST_MASK),
        };
        struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);

        if (e.cidr == 0)
                return -EINVAL;
        if (adt == IPSET_TEST)
                e.cidr = HOST_MASK;

        ip4addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip);
        e.ip &= ip_set_netmask(e.cidr);

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

static int
hash_net4_uadt(struct ip_set *set, struct nlattr *tb[],
               enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
{
        struct hash_net4 *h = set->data;
        ipset_adtfn adtfn = set->variant->adt[adt];
        struct hash_net4_elem e = { .cidr = HOST_MASK };
        struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
        u32 ip = 0, ip_to = 0, i = 0;
        int ret;

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

        if (unlikely(!tb[IPSET_ATTR_IP] ||
                     !ip_set_optattr_netorder(tb, IPSET_ATTR_CADT_FLAGS)))
                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 (tb[IPSET_ATTR_CIDR]) {
                e.cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
                if (!e.cidr || e.cidr > HOST_MASK)
                        return -IPSET_ERR_INVALID_CIDR;
        }

        if (tb[IPSET_ATTR_CADT_FLAGS]) {
                u32 cadt_flags = ip_set_get_h32(tb[IPSET_ATTR_CADT_FLAGS]);

                if (cadt_flags & IPSET_FLAG_NOMATCH)
                        flags |= (IPSET_FLAG_NOMATCH << 16);
        }

        if (adt == IPSET_TEST || !tb[IPSET_ATTR_IP_TO]) {
                e.ip = htonl(ip & ip_set_hostmask(e.cidr));
                ret = adtfn(set, &e, &ext, &ext, flags);
                return ip_set_enomatch(ret, flags, adt, set) ? -ret :
                       ip_set_eexist(ret, flags) ? 0 : ret;
        }

        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_to < ip)
                        swap(ip, ip_to);
                if (ip + UINT_MAX == ip_to)
                        return -IPSET_ERR_HASH_RANGE;
        }

        if (retried)
                ip = ntohl(h->next.ip);
        do {
                i++;
                e.ip = htonl(ip);
                if (i > IPSET_MAX_RANGE) {
                        hash_net4_data_next(&h->next, &e);
                        return -ERANGE;
                }
                ip = ip_set_range_to_cidr(ip, ip_to, &e.cidr);
                ret = adtfn(set, &e, &ext, &ext, flags);
                if (ret && !ip_set_eexist(ret, flags))
                        return ret;

                ret = 0;
        } while (ip++ < ip_to);
        return ret;
}

/* IPv6 variant */

struct hash_net6_elem {
        union nf_inet_addr ip;
        u16 padding0;
        u8 nomatch;
        u8 cidr;
};

/* Common functions */

static bool
hash_net6_data_equal(const struct hash_net6_elem *ip1,
                     const struct hash_net6_elem *ip2,
                     u32 *multi)
{
        return ipv6_addr_equal(&ip1->ip.in6, &ip2->ip.in6) &&
               ip1->cidr == ip2->cidr;
}

static int
hash_net6_do_data_match(const struct hash_net6_elem *elem)
{
        return elem->nomatch ? -ENOTEMPTY : 1;
}

static void
hash_net6_data_set_flags(struct hash_net6_elem *elem, u32 flags)
{
        elem->nomatch = (flags >> 16) & IPSET_FLAG_NOMATCH;
}

static void
hash_net6_data_reset_flags(struct hash_net6_elem *elem, u8 *flags)
{
        swap(*flags, elem->nomatch);
}

static void
hash_net6_data_netmask(struct hash_net6_elem *elem, u8 cidr)
{
        ip6_netmask(&elem->ip, cidr);
        elem->cidr = cidr;
}

static bool
hash_net6_data_list(struct sk_buff *skb, const struct hash_net6_elem *data)
{
        u32 flags = data->nomatch ? IPSET_FLAG_NOMATCH : 0;

        if (nla_put_ipaddr6(skb, IPSET_ATTR_IP, &data->ip.in6) ||
            nla_put_u8(skb, IPSET_ATTR_CIDR, data->cidr) ||
            (flags &&
             nla_put_net32(skb, IPSET_ATTR_CADT_FLAGS, htonl(flags))))
                goto nla_put_failure;
        return false;

nla_put_failure:
        return true;
}

static void
hash_net6_data_next(struct hash_net6_elem *next,
                    const struct hash_net6_elem *d)
{
}

#undef MTYPE
#undef HOST_MASK

#define MTYPE           hash_net6
#define HOST_MASK       128
#define IP_SET_EMIT_CREATE
#include "ip_set_hash_gen.h"

static int
hash_net6_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)
{
        const struct hash_net6 *h = set->data;
        ipset_adtfn adtfn = set->variant->adt[adt];
        struct hash_net6_elem e = {
                .cidr = INIT_CIDR(h->nets[0].cidr[0], HOST_MASK),
        };
        struct ip_set_ext ext = IP_SET_INIT_KEXT(skb, opt, set);

        if (e.cidr == 0)
                return -EINVAL;
        if (adt == IPSET_TEST)
                e.cidr = HOST_MASK;

        ip6addrptr(skb, opt->flags & IPSET_DIM_ONE_SRC, &e.ip.in6);
        ip6_netmask(&e.ip, e.cidr);

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

static int
hash_net6_uadt(struct ip_set *set, struct nlattr *tb[],
               enum ipset_adt adt, u32 *lineno, u32 flags, bool retried)
{
        ipset_adtfn adtfn = set->variant->adt[adt];
        struct hash_net6_elem e = { .cidr = HOST_MASK };
        struct ip_set_ext ext = IP_SET_INIT_UEXT(set);
        int ret;

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

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

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

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

        if (tb[IPSET_ATTR_CIDR]) {
                e.cidr = nla_get_u8(tb[IPSET_ATTR_CIDR]);
                if (!e.cidr || e.cidr > HOST_MASK)
                        return -IPSET_ERR_INVALID_CIDR;
        }

        ip6_netmask(&e.ip, e.cidr);

        if (tb[IPSET_ATTR_CADT_FLAGS]) {
                u32 cadt_flags = ip_set_get_h32(tb[IPSET_ATTR_CADT_FLAGS]);

                if (cadt_flags & IPSET_FLAG_NOMATCH)
                        flags |= (IPSET_FLAG_NOMATCH << 16);
        }

        ret = adtfn(set, &e, &ext, &ext, flags);

        return ip_set_enomatch(ret, flags, adt, set) ? -ret :
               ip_set_eexist(ret, flags) ? 0 : ret;
}

static struct ip_set_type hash_net_type __read_mostly = {
        .name           = "hash:net",
        .protocol       = IPSET_PROTOCOL,
        .features       = IPSET_TYPE_IP | IPSET_TYPE_NOMATCH,
        .dimension      = IPSET_DIM_ONE,
        .family         = NFPROTO_UNSPEC,
        .revision_min   = IPSET_TYPE_REV_MIN,
        .revision_max   = IPSET_TYPE_REV_MAX,
        .create_flags[IPSET_TYPE_REV_MAX] = IPSET_CREATE_FLAG_BUCKETSIZE,
        .create         = hash_net_create,
        .create_policy  = {
                [IPSET_ATTR_HASHSIZE]   = { .type = NLA_U32 },
                [IPSET_ATTR_MAXELEM]    = { .type = NLA_U32 },
                [IPSET_ATTR_INITVAL]    = { .type = NLA_U32 },
                [IPSET_ATTR_BUCKETSIZE] = { .type = NLA_U8 },
                [IPSET_ATTR_RESIZE]     = { .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_CADT_FLAGS] = { .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
hash_net_init(void)
{
        return ip_set_type_register(&hash_net_type);
}

static void __exit
hash_net_fini(void)
{
        rcu_barrier();
        ip_set_type_unregister(&hash_net_type);
}

module_init(hash_net_init);
module_exit(hash_net_fini);