LXR linux/net/netfilter/xt

   1/*
   2 *      xt_iprange - Netfilter module to match IP address ranges
   3 *
   4 *      (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
   5 *      (C) CC Computer Consultants GmbH, 2008
   6 *
   7 *      This program is free software; you can redistribute it and/or modify
   8 *      it under the terms of the GNU General Public License version 2 as
   9 *      published by the Free Software Foundation.
  10 */
  11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12#include <linux/module.h>
  13#include <linux/skbuff.h>
  14#include <linux/ip.h>
  15#include <linux/ipv6.h>
  16#include <linux/netfilter/x_tables.h>
  17#include <linux/netfilter/xt_iprange.h>
  18
  19static bool
  20iprange_mt4(const struct sk_buff *skb, struct xt_action_param *par)
  21{
  22        const struct xt_iprange_mtinfo *info = par->matchinfo;
  23        const struct iphdr *iph = ip_hdr(skb);
  24        bool m;
  25
  26        if (info->flags & IPRANGE_SRC) {
  27                m  = ntohl(iph->saddr) < ntohl(info->src_min.ip);
  28                m |= ntohl(iph->saddr) > ntohl(info->src_max.ip);
  29                m ^= !!(info->flags & IPRANGE_SRC_INV);
  30                if (m) {
  31                        pr_debug("src IP %pI4 NOT in range %s%pI4-%pI4\n",
  32                                 &iph->saddr,
  33                                 (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  34                                 &info->src_min.ip,
  35                                 &info->src_max.ip);
  36                        return false;
  37                }
  38        }
  39        if (info->flags & IPRANGE_DST) {
  40                m  = ntohl(iph->daddr) < ntohl(info->dst_min.ip);
  41                m |= ntohl(iph->daddr) > ntohl(info->dst_max.ip);
  42                m ^= !!(info->flags & IPRANGE_DST_INV);
  43                if (m) {
  44                        pr_debug("dst IP %pI4 NOT in range %s%pI4-%pI4\n",
  45                                 &iph->daddr,
  46                                 (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  47                                 &info->dst_min.ip,
  48                                 &info->dst_max.ip);
  49                        return false;
  50                }
  51        }
  52        return true;
  53}
  54
  55static inline int
  56iprange_ipv6_lt(const struct in6_addr *a, const struct in6_addr *b)
  57{
  58        unsigned int i;
  59
  60        for (i = 0; i < 4; ++i) {
  61                if (a->s6_addr32[i] != b->s6_addr32[i])
  62                        return ntohl(a->s6_addr32[i]) < ntohl(b->s6_addr32[i]);
  63        }
  64
  65        return 0;
  66}
  67
  68static bool
  69iprange_mt6(const struct sk_buff *skb, struct xt_action_param *par)
  70{
  71        const struct xt_iprange_mtinfo *info = par->matchinfo;
  72        const struct ipv6hdr *iph = ipv6_hdr(skb);
  73        bool m;
  74
  75        if (info->flags & IPRANGE_SRC) {
  76                m  = iprange_ipv6_lt(&iph->saddr, &info->src_min.in6);
  77                m |= iprange_ipv6_lt(&info->src_max.in6, &iph->saddr);
  78                m ^= !!(info->flags & IPRANGE_SRC_INV);
  79                if (m) {
  80                        pr_debug("src IP %pI6 NOT in range %s%pI6-%pI6\n",
  81                                 &iph->saddr,
  82                                 (info->flags & IPRANGE_SRC_INV) ? "(INV) " : "",
  83                                 &info->src_min.in6,
  84                                 &info->src_max.in6);
  85                        return false;
  86                }
  87        }
  88        if (info->flags & IPRANGE_DST) {
  89                m  = iprange_ipv6_lt(&iph->daddr, &info->dst_min.in6);
  90                m |= iprange_ipv6_lt(&info->dst_max.in6, &iph->daddr);
  91                m ^= !!(info->flags & IPRANGE_DST_INV);
  92                if (m) {
  93                        pr_debug("dst IP %pI6 NOT in range %s%pI6-%pI6\n",
  94                                 &iph->daddr,
  95                                 (info->flags & IPRANGE_DST_INV) ? "(INV) " : "",
  96                                 &info->dst_min.in6,
  97                                 &info->dst_max.in6);
  98                        return false;
  99                }
 100        }
 101        return true;
 102}
 103
 104static struct xt_match iprange_mt_reg[] __read_mostly = {
 105        {
 106                .name      = "iprange",
 107                .revision  = 1,
 108                .family    = NFPROTO_IPV4,
 109                .match     = iprange_mt4,
 110                .matchsize = sizeof(struct xt_iprange_mtinfo),
 111                .me        = THIS_MODULE,
 112        },
 113        {
 114                .name      = "iprange",
 115                .revision  = 1,
 116                .family    = NFPROTO_IPV6,
 117                .match     = iprange_mt6,
 118                .matchsize = sizeof(struct xt_iprange_mtinfo),
 119                .me        = THIS_MODULE,
 120        },
 121};
 122
 123static int __init iprange_mt_init(void)
 124{
 125        return xt_register_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 126}
 127
 128static void __exit iprange_mt_exit(void)
 129{
 130        xt_unregister_matches(iprange_mt_reg, ARRAY_SIZE(iprange_mt_reg));
 131}
 132
 133module_init(iprange_mt_init);
 134module_exit(iprange_mt_exit);
 135MODULE_LICENSE("GPL");
 136MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
 137MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
 138MODULE_DESCRIPTION("Xtables: arbitrary IPv4 range matching");
 139MODULE_ALIAS("ipt_iprange");
 140MODULE_ALIAS("ip6t_iprange");
 141