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14#include <linux/ip.h>
15#include <net/ip.h>
16#include <linux/in.h>
17#include <linux/module.h>
18#include <linux/netfilter/x_tables.h>
19#include <linux/netfilter_bridge/ebtables.h>
20#include <linux/netfilter_bridge/ebt_ip.h>
21
22union pkthdr {
23 struct {
24 __be16 src;
25 __be16 dst;
26 } tcpudphdr;
27 struct {
28 u8 type;
29 u8 code;
30 } icmphdr;
31 struct {
32 u8 type;
33 } igmphdr;
34};
35
36static bool
37ebt_ip_mt(const struct sk_buff *skb, struct xt_action_param *par)
38{
39 const struct ebt_ip_info *info = par->matchinfo;
40 const struct iphdr *ih;
41 struct iphdr _iph;
42 const union pkthdr *pptr;
43 union pkthdr _pkthdr;
44
45 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
46 if (ih == NULL)
47 return false;
48 if ((info->bitmask & EBT_IP_TOS) &&
49 NF_INVF(info, EBT_IP_TOS, info->tos != ih->tos))
50 return false;
51 if ((info->bitmask & EBT_IP_SOURCE) &&
52 NF_INVF(info, EBT_IP_SOURCE,
53 (ih->saddr & info->smsk) != info->saddr))
54 return false;
55 if ((info->bitmask & EBT_IP_DEST) &&
56 NF_INVF(info, EBT_IP_DEST,
57 (ih->daddr & info->dmsk) != info->daddr))
58 return false;
59 if (info->bitmask & EBT_IP_PROTO) {
60 if (NF_INVF(info, EBT_IP_PROTO, info->protocol != ih->protocol))
61 return false;
62 if (!(info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT |
63 EBT_IP_ICMP | EBT_IP_IGMP)))
64 return true;
65 if (ntohs(ih->frag_off) & IP_OFFSET)
66 return false;
67
68
69 pptr = skb_header_pointer(skb, ih->ihl*4,
70 sizeof(_pkthdr), &_pkthdr);
71 if (pptr == NULL)
72 return false;
73 if (info->bitmask & EBT_IP_DPORT) {
74 u32 dst = ntohs(pptr->tcpudphdr.dst);
75 if (NF_INVF(info, EBT_IP_DPORT,
76 dst < info->dport[0] ||
77 dst > info->dport[1]))
78 return false;
79 }
80 if (info->bitmask & EBT_IP_SPORT) {
81 u32 src = ntohs(pptr->tcpudphdr.src);
82 if (NF_INVF(info, EBT_IP_SPORT,
83 src < info->sport[0] ||
84 src > info->sport[1]))
85 return false;
86 }
87 if ((info->bitmask & EBT_IP_ICMP) &&
88 NF_INVF(info, EBT_IP_ICMP,
89 pptr->icmphdr.type < info->icmp_type[0] ||
90 pptr->icmphdr.type > info->icmp_type[1] ||
91 pptr->icmphdr.code < info->icmp_code[0] ||
92 pptr->icmphdr.code > info->icmp_code[1]))
93 return false;
94 if ((info->bitmask & EBT_IP_IGMP) &&
95 NF_INVF(info, EBT_IP_IGMP,
96 pptr->igmphdr.type < info->igmp_type[0] ||
97 pptr->igmphdr.type > info->igmp_type[1]))
98 return false;
99 }
100 return true;
101}
102
103static int ebt_ip_mt_check(const struct xt_mtchk_param *par)
104{
105 const struct ebt_ip_info *info = par->matchinfo;
106 const struct ebt_entry *e = par->entryinfo;
107
108 if (e->ethproto != htons(ETH_P_IP) ||
109 e->invflags & EBT_IPROTO)
110 return -EINVAL;
111 if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK)
112 return -EINVAL;
113 if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) {
114 if (info->invflags & EBT_IP_PROTO)
115 return -EINVAL;
116 if (info->protocol != IPPROTO_TCP &&
117 info->protocol != IPPROTO_UDP &&
118 info->protocol != IPPROTO_UDPLITE &&
119 info->protocol != IPPROTO_SCTP &&
120 info->protocol != IPPROTO_DCCP)
121 return -EINVAL;
122 }
123 if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1])
124 return -EINVAL;
125 if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1])
126 return -EINVAL;
127 if (info->bitmask & EBT_IP_ICMP) {
128 if ((info->invflags & EBT_IP_PROTO) ||
129 info->protocol != IPPROTO_ICMP)
130 return -EINVAL;
131 if (info->icmp_type[0] > info->icmp_type[1] ||
132 info->icmp_code[0] > info->icmp_code[1])
133 return -EINVAL;
134 }
135 if (info->bitmask & EBT_IP_IGMP) {
136 if ((info->invflags & EBT_IP_PROTO) ||
137 info->protocol != IPPROTO_IGMP)
138 return -EINVAL;
139 if (info->igmp_type[0] > info->igmp_type[1])
140 return -EINVAL;
141 }
142 return 0;
143}
144
145static struct xt_match ebt_ip_mt_reg __read_mostly = {
146 .name = "ip",
147 .revision = 0,
148 .family = NFPROTO_BRIDGE,
149 .match = ebt_ip_mt,
150 .checkentry = ebt_ip_mt_check,
151 .matchsize = sizeof(struct ebt_ip_info),
152 .me = THIS_MODULE,
153};
154
155static int __init ebt_ip_init(void)
156{
157 return xt_register_match(&ebt_ip_mt_reg);
158}
159
160static void __exit ebt_ip_fini(void)
161{
162 xt_unregister_match(&ebt_ip_mt_reg);
163}
164
165module_init(ebt_ip_init);
166module_exit(ebt_ip_fini);
167MODULE_DESCRIPTION("Ebtables: IPv4 protocol packet match");
168MODULE_LICENSE("GPL");
169
