1 /*
2 * ebt_ip6
3 *
4 * Authors:
5 * Manohar Castelino <manohar.r.castelino@intel.com>
6 * Kuo-Lang Tseng <kuo-lang.tseng@intel.com>
7 * Jan Engelhardt <jengelh@medozas.de>
8 *
9 * Summary:
10 * This is just a modification of the IPv4 code written by
11 * Bart De Schuymer <bdschuym@pandora.be>
12 * with the changes required to support IPv6
13 *
14 * Jan, 2008
15 */
16 #include <linux/ipv6.h>
17 #include <net/ipv6.h>
18 #include <linux/in.h>
19 #include <linux/module.h>
20 #include <net/dsfield.h>
21 #include <linux/netfilter/x_tables.h>
22 #include <linux/netfilter_bridge/ebtables.h>
23 #include <linux/netfilter_bridge/ebt_ip6.h>
24
25 union pkthdr {
26 struct {
27 __be16 src;
28 __be16 dst;
29 } tcpudphdr;
30 struct {
31 u8 type;
32 u8 code;
33 } icmphdr;
34 };
35
36 static bool
37 ebt_ip6_mt(const struct sk_buff *skb, struct xt_action_param *par)
38 {
39 const struct ebt_ip6_info *info = par->matchinfo;
40 const struct ipv6hdr *ih6;
41 struct ipv6hdr _ip6h;
42 const union pkthdr *pptr;
43 union pkthdr _pkthdr;
44
45 ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
46 if (ih6 == NULL)
47 return false;
48 if ((info->bitmask & EBT_IP6_TCLASS) &&
49 NF_INVF(info, EBT_IP6_TCLASS,
50 info->tclass != ipv6_get_dsfield(ih6)))
51 return false;
52 if (((info->bitmask & EBT_IP6_SOURCE) &&
53 NF_INVF(info, EBT_IP6_SOURCE,
54 ipv6_masked_addr_cmp(&ih6->saddr, &info->smsk,
55 &info->saddr))) ||
56 ((info->bitmask & EBT_IP6_DEST) &&
57 NF_INVF(info, EBT_IP6_DEST,
58 ipv6_masked_addr_cmp(&ih6->daddr, &info->dmsk,
59 &info->daddr))))
60 return false;
61 if (info->bitmask & EBT_IP6_PROTO) {
62 uint8_t nexthdr = ih6->nexthdr;
63 __be16 frag_off;
64 int offset_ph;
65
66 offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr, &frag_off);
67 if (offset_ph == -1)
68 return false;
69 if (NF_INVF(info, EBT_IP6_PROTO, info->protocol != nexthdr))
70 return false;
71 if (!(info->bitmask & (EBT_IP6_DPORT |
72 EBT_IP6_SPORT | EBT_IP6_ICMP6)))
73 return true;
74
75 /* min icmpv6 headersize is 4, so sizeof(_pkthdr) is ok. */
76 pptr = skb_header_pointer(skb, offset_ph, sizeof(_pkthdr),
77 &_pkthdr);
78 if (pptr == NULL)
79 return false;
80 if (info->bitmask & EBT_IP6_DPORT) {
81 u16 dst = ntohs(pptr->tcpudphdr.dst);
82 if (NF_INVF(info, EBT_IP6_DPORT,
83 dst < info->dport[0] ||
84 dst > info->dport[1]))
85 return false;
86 }
87 if (info->bitmask & EBT_IP6_SPORT) {
88 u16 src = ntohs(pptr->tcpudphdr.src);
89 if (NF_INVF(info, EBT_IP6_SPORT,
90 src < info->sport[0] ||
91 src > info->sport[1]))
92 return false;
93 }
94 if ((info->bitmask & EBT_IP6_ICMP6) &&
95 NF_INVF(info, EBT_IP6_ICMP6,
96 pptr->icmphdr.type < info->icmpv6_type[0] ||
97 pptr->icmphdr.type > info->icmpv6_type[1] ||
98 pptr->icmphdr.code < info->icmpv6_code[0] ||
99 pptr->icmphdr.code > info->icmpv6_code[1]))
100 return false;
101 }
102 return true;
103 }
104
105 static int ebt_ip6_mt_check(const struct xt_mtchk_param *par)
106 {
107 const struct ebt_entry *e = par->entryinfo;
108 struct ebt_ip6_info *info = par->matchinfo;
109
110 if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
111 return -EINVAL;
112 if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
113 return -EINVAL;
114 if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
115 if (info->invflags & EBT_IP6_PROTO)
116 return -EINVAL;
117 if (info->protocol != IPPROTO_TCP &&
118 info->protocol != IPPROTO_UDP &&
119 info->protocol != IPPROTO_UDPLITE &&
120 info->protocol != IPPROTO_SCTP &&
121 info->protocol != IPPROTO_DCCP)
122 return -EINVAL;
123 }
124 if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
125 return -EINVAL;
126 if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
127 return -EINVAL;
128 if (info->bitmask & EBT_IP6_ICMP6) {
129 if ((info->invflags & EBT_IP6_PROTO) ||
130 info->protocol != IPPROTO_ICMPV6)
131 return -EINVAL;
132 if (info->icmpv6_type[0] > info->icmpv6_type[1] ||
133 info->icmpv6_code[0] > info->icmpv6_code[1])
134 return -EINVAL;
135 }
136 return 0;
137 }
138
139 static struct xt_match ebt_ip6_mt_reg __read_mostly = {
140 .name = "ip6",
141 .revision = 0,
142 .family = NFPROTO_BRIDGE,
143 .match = ebt_ip6_mt,
144 .checkentry = ebt_ip6_mt_check,
145 .matchsize = sizeof(struct ebt_ip6_info),
146 .me = THIS_MODULE,
147 };
148
149 static int __init ebt_ip6_init(void)
150 {
151 return xt_register_match(&ebt_ip6_mt_reg);
152 }
153
154 static void __exit ebt_ip6_fini(void)
155 {
156 xt_unregister_match(&ebt_ip6_mt_reg);
157 }
158
159 module_init(ebt_ip6_init);
160 module_exit(ebt_ip6_fini);
161 MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
162 MODULE_AUTHOR("Kuo-Lang Tseng <kuo-lang.tseng@intel.com>");
163 MODULE_LICENSE("GPL");
164
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