root/net/netfilter/xt_iprange.c

DEFINITIONS

1. iprange_mt_v0
2. iprange_mt4
3. iprange_ipv6_sub
4. iprange_mt6
5. iprange_mt_init
6. iprange_mt_exit

/*
 *      xt_iprange - Netfilter module to match IP address ranges
 *
 *      (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
 *      (C) CC Computer Consultants GmbH, 2008
 *
 *      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.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_iprange.h>
#include <linux/netfilter_ipv4/ipt_iprange.h>

static bool
iprange_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct ipt_iprange_info *info = par->matchinfo;
        const struct iphdr *iph = ip_hdr(skb);

        if (info->flags & IPRANGE_SRC) {
                if ((ntohl(iph->saddr) < ntohl(info->src.min_ip)
                          || ntohl(iph->saddr) > ntohl(info->src.max_ip))
                         ^ !!(info->flags & IPRANGE_SRC_INV)) {
                        pr_debug("src IP %u.%u.%u.%u NOT in range %s"
                                 "%u.%u.%u.%u-%u.%u.%u.%u\n",
                                 NIPQUAD(iph->saddr),
                                 info->flags & IPRANGE_SRC_INV ? "(INV) " : "",
                                 NIPQUAD(info->src.min_ip),
                                 NIPQUAD(info->src.max_ip));
                        return false;
                }
        }
        if (info->flags & IPRANGE_DST) {
                if ((ntohl(iph->daddr) < ntohl(info->dst.min_ip)
                          || ntohl(iph->daddr) > ntohl(info->dst.max_ip))
                         ^ !!(info->flags & IPRANGE_DST_INV)) {
                        pr_debug("dst IP %u.%u.%u.%u NOT in range %s"
                                 "%u.%u.%u.%u-%u.%u.%u.%u\n",
                                 NIPQUAD(iph->daddr),
                                 info->flags & IPRANGE_DST_INV ? "(INV) " : "",
                                 NIPQUAD(info->dst.min_ip),
                                 NIPQUAD(info->dst.max_ip));
                        return false;
                }
        }
        return true;
}

static bool
iprange_mt4(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct xt_iprange_mtinfo *info = par->matchinfo;
        const struct iphdr *iph = ip_hdr(skb);
        bool m;

        if (info->flags & IPRANGE_SRC) {
                m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
                m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
                m ^= info->flags & IPRANGE_SRC_INV;
                if (m) {
                        pr_debug("src IP " NIPQUAD_FMT " NOT in range %s"
                                 NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
                                 NIPQUAD(iph->saddr),
                                 (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
                                 NIPQUAD(info->src_max.ip),
                                 NIPQUAD(info->src_max.ip));
                        return false;
                }
        }
        if (info->flags & IPRANGE_DST) {
                m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
                m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
                m ^= info->flags & IPRANGE_DST_INV;
                if (m) {
                        pr_debug("dst IP " NIPQUAD_FMT " NOT in range %s"
                                 NIPQUAD_FMT "-" NIPQUAD_FMT "\n",
                                 NIPQUAD(iph->daddr),
                                 (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
                                 NIPQUAD(info->dst_min.ip),
                                 NIPQUAD(info->dst_max.ip));
                        return false;
                }
        }
        return true;
}

static inline int
iprange_ipv6_sub(const struct in6_addr *a, const struct in6_addr *b)
{
        unsigned int i;
        int r;

        for (i = 0; i < 4; ++i) {
                r = ntohl(a->s6_addr32[i]) - ntohl(b->s6_addr32[i]);
                if (r != 0)
                        return r;
        }

        return 0;
}

static bool
iprange_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct xt_iprange_mtinfo *info = par->matchinfo;
        const struct ipv6hdr *iph = ipv6_hdr(skb);
        bool m;

        if (info->flags & IPRANGE_SRC) {
                m  = iprange_ipv6_sub(&iph->saddr, &info->src_min.in6) < 0;
                m |= iprange_ipv6_sub(&iph->saddr, &info->src_max.in6) > 0;
                m ^= info->flags & IPRANGE_SRC_INV;
                if (m)
                        return false;
        }
        if (info->flags & IPRANGE_DST) {
                m  = iprange_ipv6_sub(&iph->daddr, &info->dst_min.in6) < 0;
                m |= iprange_ipv6_sub(&iph->daddr, &info->dst_max.in6) > 0;
                m ^= info->flags & IPRANGE_DST_INV;
                if (m)
                        return false;
        }
        return true;
}

static struct xt_match iprange_mt_reg[] __read_mostly = {
        {
                .name      = "iprange",
                .revision  = 0,
                .family    = NFPROTO_IPV4,
                .match     = iprange_mt_v0,
                .matchsize = sizeof(struct ipt_iprange_info),
                .me        = THIS_MODULE,
        },
        {
                .name      = "iprange",
                .revision  = 1,
                .family    = NFPROTO_IPV4,
                .match     = iprange_mt4,
                .matchsize = sizeof(struct xt_iprange_mtinfo),
                .me        = THIS_MODULE,
        },
        {
                .name      = "iprange",
                .revision  = 1,
                .family    = NFPROTO_IPV6,
                .match     = iprange_mt6,
                .matchsize = sizeof(struct xt_iprange_mtinfo),
                .me        = THIS_MODULE,
        },
};

static int __init iprange_mt_init(void)
{
        return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
}

static void __exit iprange_mt_exit(void)
{
        xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
}

module_init(iprange_mt_init);
module_exit(iprange_mt_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>, Jan Engelhardt <jengelh@computergmbh.de>");
MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
MODULE_ALIAS("ipt_iprange");
MODULE_ALIAS("ip6t_iprange");