LXR linux/net/ipv4/netfilter/ipt

   1/*
   2 *  iptables module to match inet_addr_type() of an ip.
   3 *
   4 *  Copyright (c) 2004 Patrick McHardy <kaber@trash.net>
   5 *  (C) 2007 Laszlo Attila Toth <panther@balabit.hu>
   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/kernel.h>
  13#include <linux/module.h>
  14#include <linux/skbuff.h>
  15#include <linux/netdevice.h>
  16#include <linux/ip.h>
  17#include <net/route.h>
  18
  19#include <linux/netfilter_ipv4/ipt_addrtype.h>
  20#include <linux/netfilter/x_tables.h>
  21
  22MODULE_LICENSE("GPL");
  23MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  24MODULE_DESCRIPTION("Xtables: address type match for IPv4");
  25
  26static inline bool match_type(struct net *net, const struct net_device *dev,
  27                              __be32 addr, u_int16_t mask)
  28{
  29        return !!(mask & (1 << inet_dev_addr_type(net, dev, addr)));
  30}
  31
  32static bool
  33addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par)
  34{
  35        struct net *net = dev_net(par->in ? par->in : par->out);
  36        const struct ipt_addrtype_info *info = par->matchinfo;
  37        const struct iphdr *iph = ip_hdr(skb);
  38        bool ret = true;
  39
  40        if (info->source)
  41                ret &= match_type(net, NULL, iph->saddr, info->source) ^
  42                       info->invert_source;
  43        if (info->dest)
  44                ret &= match_type(net, NULL, iph->daddr, info->dest) ^
  45                       info->invert_dest;
  46
  47        return ret;
  48}
  49
  50static bool
  51addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
  52{
  53        struct net *net = dev_net(par->in ? par->in : par->out);
  54        const struct ipt_addrtype_info_v1 *info = par->matchinfo;
  55        const struct iphdr *iph = ip_hdr(skb);
  56        const struct net_device *dev = NULL;
  57        bool ret = true;
  58
  59        if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN)
  60                dev = par->in;
  61        else if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT)
  62                dev = par->out;
  63
  64        if (info->source)
  65                ret &= match_type(net, dev, iph->saddr, info->source) ^
  66                       (info->flags & IPT_ADDRTYPE_INVERT_SOURCE);
  67        if (ret && info->dest)
  68                ret &= match_type(net, dev, iph->daddr, info->dest) ^
  69                       !!(info->flags & IPT_ADDRTYPE_INVERT_DEST);
  70        return ret;
  71}
  72
  73static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
  74{
  75        struct ipt_addrtype_info_v1 *info = par->matchinfo;
  76
  77        if (info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN &&
  78            info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT) {
  79                pr_info("both incoming and outgoing "
  80                        "interface limitation cannot be selected\n");
  81                return -EINVAL;
  82        }
  83
  84        if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) |
  85            (1 << NF_INET_LOCAL_IN)) &&
  86            info->flags & IPT_ADDRTYPE_LIMIT_IFACE_OUT) {
  87                pr_info("output interface limitation "
  88                        "not valid in PREROUTING and INPUT\n");
  89                return -EINVAL;
  90        }
  91
  92        if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) |
  93            (1 << NF_INET_LOCAL_OUT)) &&
  94            info->flags & IPT_ADDRTYPE_LIMIT_IFACE_IN) {
  95                pr_info("input interface limitation "
  96                        "not valid in POSTROUTING and OUTPUT\n");
  97                return -EINVAL;
  98        }
  99
 100        return 0;
 101}
 102
 103static struct xt_match addrtype_mt_reg[] __read_mostly = {
 104        {
 105                .name           = "addrtype",
 106                .family         = NFPROTO_IPV4,
 107                .match          = addrtype_mt_v0,
 108                .matchsize      = sizeof(struct ipt_addrtype_info),
 109                .me             = THIS_MODULE
 110        },
 111        {
 112                .name           = "addrtype",
 113                .family         = NFPROTO_IPV4,
 114                .revision       = 1,
 115                .match          = addrtype_mt_v1,
 116                .checkentry     = addrtype_mt_checkentry_v1,
 117                .matchsize      = sizeof(struct ipt_addrtype_info_v1),
 118                .me             = THIS_MODULE
 119        }
 120};
 121
 122static int __init addrtype_mt_init(void)
 123{
 124        return xt_register_matches(addrtype_mt_reg,
 125                                   ARRAY_SIZE(addrtype_mt_reg));
 126}
 127
 128static void __exit addrtype_mt_exit(void)
 129{
 130        xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
 131}
 132
 133module_init(addrtype_mt_init);
 134module_exit(addrtype_mt_exit);
 135