65caa00dcf2a348d0c321a42add55acd40177339
[linux-2.6.git] / net / bridge / netfilter / ebt_ip.c
1 /*
2  *  ebt_ip
3  *
4  *      Authors:
5  *      Bart De Schuymer <bdschuym@pandora.be>
6  *
7  *  April, 2002
8  *
9  *  Changes:
10  *    added ip-sport and ip-dport
11  *    Innominate Security Technologies AG <mhopf@innominate.com>
12  *    September, 2002
13  */
14
15 #include <linux/netfilter_bridge/ebtables.h>
16 #include <linux/netfilter_bridge/ebt_ip.h>
17 #include <linux/ip.h>
18 #include <net/ip.h>
19 #include <linux/in.h>
20 #include <linux/module.h>
21
22 struct tcpudphdr {
23         __be16 src;
24         __be16 dst;
25 };
26
27 static int ebt_filter_ip(const struct sk_buff *skb, const struct net_device *in,
28    const struct net_device *out, const void *data,
29    unsigned int datalen)
30 {
31         const struct ebt_ip_info *info = data;
32         const struct iphdr *ih;
33         struct iphdr _iph;
34         const struct tcpudphdr *pptr;
35         struct tcpudphdr _ports;
36
37         ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
38         if (ih == NULL)
39                 return EBT_NOMATCH;
40         if (info->bitmask & EBT_IP_TOS &&
41            FWINV(info->tos != ih->tos, EBT_IP_TOS))
42                 return EBT_NOMATCH;
43         if (info->bitmask & EBT_IP_SOURCE &&
44            FWINV((ih->saddr & info->smsk) !=
45            info->saddr, EBT_IP_SOURCE))
46                 return EBT_NOMATCH;
47         if ((info->bitmask & EBT_IP_DEST) &&
48            FWINV((ih->daddr & info->dmsk) !=
49            info->daddr, EBT_IP_DEST))
50                 return EBT_NOMATCH;
51         if (info->bitmask & EBT_IP_PROTO) {
52                 if (FWINV(info->protocol != ih->protocol, EBT_IP_PROTO))
53                         return EBT_NOMATCH;
54                 if (!(info->bitmask & EBT_IP_DPORT) &&
55                     !(info->bitmask & EBT_IP_SPORT))
56                         return EBT_MATCH;
57                 if (ntohs(ih->frag_off) & IP_OFFSET)
58                         return EBT_NOMATCH;
59                 pptr = skb_header_pointer(skb, ih->ihl*4,
60                                           sizeof(_ports), &_ports);
61                 if (pptr == NULL)
62                         return EBT_NOMATCH;
63                 if (info->bitmask & EBT_IP_DPORT) {
64                         u32 dst = ntohs(pptr->dst);
65                         if (FWINV(dst < info->dport[0] ||
66                                   dst > info->dport[1],
67                                   EBT_IP_DPORT))
68                         return EBT_NOMATCH;
69                 }
70                 if (info->bitmask & EBT_IP_SPORT) {
71                         u32 src = ntohs(pptr->src);
72                         if (FWINV(src < info->sport[0] ||
73                                   src > info->sport[1],
74                                   EBT_IP_SPORT))
75                         return EBT_NOMATCH;
76                 }
77         }
78         return EBT_MATCH;
79 }
80
81 static int ebt_ip_check(const char *tablename, unsigned int hookmask,
82    const struct ebt_entry *e, void *data, unsigned int datalen)
83 {
84         const struct ebt_ip_info *info = data;
85
86         if (datalen != EBT_ALIGN(sizeof(struct ebt_ip_info)))
87                 return -EINVAL;
88         if (e->ethproto != htons(ETH_P_IP) ||
89            e->invflags & EBT_IPROTO)
90                 return -EINVAL;
91         if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK)
92                 return -EINVAL;
93         if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) {
94                 if (info->invflags & EBT_IP_PROTO)
95                         return -EINVAL;
96                 if (info->protocol != IPPROTO_TCP &&
97                     info->protocol != IPPROTO_UDP &&
98                     info->protocol != IPPROTO_UDPLITE &&
99                     info->protocol != IPPROTO_SCTP &&
100                     info->protocol != IPPROTO_DCCP)
101                          return -EINVAL;
102         }
103         if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1])
104                 return -EINVAL;
105         if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1])
106                 return -EINVAL;
107         return 0;
108 }
109
110 static struct ebt_match filter_ip __read_mostly = {
111         .name           = EBT_IP_MATCH,
112         .match          = ebt_filter_ip,
113         .check          = ebt_ip_check,
114         .me             = THIS_MODULE,
115 };
116
117 static int __init ebt_ip_init(void)
118 {
119         return ebt_register_match(&filter_ip);
120 }
121
122 static void __exit ebt_ip_fini(void)
123 {
124         ebt_unregister_match(&filter_ip);
125 }
126
127 module_init(ebt_ip_init);
128 module_exit(ebt_ip_fini);
129 MODULE_DESCRIPTION("Ebtables: IPv4 protocol packet match");
130 MODULE_LICENSE("GPL");