Commit | Line | Data |
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1da177e4 LT |
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> | |
8a4c8a96 | 18 | #include <net/ip.h> |
1da177e4 LT |
19 | #include <linux/in.h> |
20 | #include <linux/module.h> | |
21 | ||
22 | struct tcpudphdr { | |
23 | uint16_t src; | |
24 | uint16_t 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 | struct ebt_ip_info *info = (struct ebt_ip_info *)data; | |
32 | struct iphdr _iph, *ih; | |
33 | struct tcpudphdr _ports, *pptr; | |
34 | ||
35 | ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph); | |
36 | if (ih == NULL) | |
37 | return EBT_NOMATCH; | |
38 | if (info->bitmask & EBT_IP_TOS && | |
39 | FWINV(info->tos != ih->tos, EBT_IP_TOS)) | |
40 | return EBT_NOMATCH; | |
41 | if (info->bitmask & EBT_IP_SOURCE && | |
42 | FWINV((ih->saddr & info->smsk) != | |
43 | info->saddr, EBT_IP_SOURCE)) | |
44 | return EBT_NOMATCH; | |
45 | if ((info->bitmask & EBT_IP_DEST) && | |
46 | FWINV((ih->daddr & info->dmsk) != | |
47 | info->daddr, EBT_IP_DEST)) | |
48 | return EBT_NOMATCH; | |
49 | if (info->bitmask & EBT_IP_PROTO) { | |
50 | if (FWINV(info->protocol != ih->protocol, EBT_IP_PROTO)) | |
51 | return EBT_NOMATCH; | |
52 | if (!(info->bitmask & EBT_IP_DPORT) && | |
53 | !(info->bitmask & EBT_IP_SPORT)) | |
54 | return EBT_MATCH; | |
8a4c8a96 BDS |
55 | if (ntohs(ih->frag_off) & IP_OFFSET) |
56 | return EBT_NOMATCH; | |
1da177e4 LT |
57 | pptr = skb_header_pointer(skb, ih->ihl*4, |
58 | sizeof(_ports), &_ports); | |
59 | if (pptr == NULL) | |
60 | return EBT_NOMATCH; | |
61 | if (info->bitmask & EBT_IP_DPORT) { | |
62 | u32 dst = ntohs(pptr->dst); | |
63 | if (FWINV(dst < info->dport[0] || | |
64 | dst > info->dport[1], | |
65 | EBT_IP_DPORT)) | |
66 | return EBT_NOMATCH; | |
67 | } | |
68 | if (info->bitmask & EBT_IP_SPORT) { | |
69 | u32 src = ntohs(pptr->src); | |
70 | if (FWINV(src < info->sport[0] || | |
71 | src > info->sport[1], | |
72 | EBT_IP_SPORT)) | |
73 | return EBT_NOMATCH; | |
74 | } | |
75 | } | |
76 | return EBT_MATCH; | |
77 | } | |
78 | ||
79 | static int ebt_ip_check(const char *tablename, unsigned int hookmask, | |
80 | const struct ebt_entry *e, void *data, unsigned int datalen) | |
81 | { | |
82 | struct ebt_ip_info *info = (struct ebt_ip_info *)data; | |
83 | ||
84 | if (datalen != EBT_ALIGN(sizeof(struct ebt_ip_info))) | |
85 | return -EINVAL; | |
86 | if (e->ethproto != htons(ETH_P_IP) || | |
87 | e->invflags & EBT_IPROTO) | |
88 | return -EINVAL; | |
89 | if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK) | |
90 | return -EINVAL; | |
91 | if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) { | |
92 | if (info->invflags & EBT_IP_PROTO) | |
93 | return -EINVAL; | |
94 | if (info->protocol != IPPROTO_TCP && | |
ab67a4d5 PM |
95 | info->protocol != IPPROTO_UDP && |
96 | info->protocol != IPPROTO_SCTP && | |
97 | info->protocol != IPPROTO_DCCP) | |
1da177e4 LT |
98 | return -EINVAL; |
99 | } | |
100 | if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1]) | |
101 | return -EINVAL; | |
102 | if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1]) | |
103 | return -EINVAL; | |
104 | return 0; | |
105 | } | |
106 | ||
107 | static struct ebt_match filter_ip = | |
108 | { | |
109 | .name = EBT_IP_MATCH, | |
110 | .match = ebt_filter_ip, | |
111 | .check = ebt_ip_check, | |
112 | .me = THIS_MODULE, | |
113 | }; | |
114 | ||
65b4b4e8 | 115 | static int __init ebt_ip_init(void) |
1da177e4 LT |
116 | { |
117 | return ebt_register_match(&filter_ip); | |
118 | } | |
119 | ||
65b4b4e8 | 120 | static void __exit ebt_ip_fini(void) |
1da177e4 LT |
121 | { |
122 | ebt_unregister_match(&filter_ip); | |
123 | } | |
124 | ||
65b4b4e8 AM |
125 | module_init(ebt_ip_init); |
126 | module_exit(ebt_ip_fini); | |
1da177e4 | 127 | MODULE_LICENSE("GPL"); |