netfilter: xtables: change xt_match.checkentry return type
[linux-2.6.git] / net / ipv4 / netfilter / ipt_addrtype.c
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
22 MODULE_LICENSE("GPL");
23 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
24 MODULE_DESCRIPTION("Xtables: address type match for IPv4");
25
26 static 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
32 static bool
33 addrtype_mt_v0(const struct sk_buff *skb, const struct xt_match_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
50 static bool
51 addrtype_mt_v1(const struct sk_buff *skb, const struct xt_match_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
73 static 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 false;
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 false;
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 false;
98         }
99
100         return true;
101 }
102
103 static 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
122 static int __init addrtype_mt_init(void)
123 {
124         return xt_register_matches(addrtype_mt_reg,
125                                    ARRAY_SIZE(addrtype_mt_reg));
126 }
127
128 static void __exit addrtype_mt_exit(void)
129 {
130         xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
131 }
132
133 module_init(addrtype_mt_init);
134 module_exit(addrtype_mt_exit);