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
ebt_ip6_mt(const struct sk_buff * skb,struct xt_action_param * par)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 FWINV(info->tclass != ipv6_get_dsfield(ih6), EBT_IP6_TCLASS))
50 return false;
51 if (FWINV(ipv6_masked_addr_cmp(&ih6->saddr, &info->smsk,
52 &info->saddr), EBT_IP6_SOURCE) ||
53 FWINV(ipv6_masked_addr_cmp(&ih6->daddr, &info->dmsk,
54 &info->daddr), EBT_IP6_DEST))
55 return false;
56 if (info->bitmask & EBT_IP6_PROTO) {
57 uint8_t nexthdr = ih6->nexthdr;
58 __be16 frag_off;
59 int offset_ph;
60
61 offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr, &frag_off);
62 if (offset_ph == -1)
63 return false;
64 if (FWINV(info->protocol != nexthdr, EBT_IP6_PROTO))
65 return false;
66 if (!(info->bitmask & ( EBT_IP6_DPORT |
67 EBT_IP6_SPORT | EBT_IP6_ICMP6)))
68 return true;
69
70 /* min icmpv6 headersize is 4, so sizeof(_pkthdr) is ok. */
71 pptr = skb_header_pointer(skb, offset_ph, sizeof(_pkthdr),
72 &_pkthdr);
73 if (pptr == NULL)
74 return false;
75 if (info->bitmask & EBT_IP6_DPORT) {
76 u16 dst = ntohs(pptr->tcpudphdr.dst);
77 if (FWINV(dst < info->dport[0] ||
78 dst > info->dport[1], EBT_IP6_DPORT))
79 return false;
80 }
81 if (info->bitmask & EBT_IP6_SPORT) {
82 u16 src = ntohs(pptr->tcpudphdr.src);
83 if (FWINV(src < info->sport[0] ||
84 src > info->sport[1], EBT_IP6_SPORT))
85 return false;
86 }
87 if ((info->bitmask & EBT_IP6_ICMP6) &&
88 FWINV(pptr->icmphdr.type < info->icmpv6_type[0] ||
89 pptr->icmphdr.type > info->icmpv6_type[1] ||
90 pptr->icmphdr.code < info->icmpv6_code[0] ||
91 pptr->icmphdr.code > info->icmpv6_code[1],
92 EBT_IP6_ICMP6))
93 return false;
94 }
95 return true;
96 }
97
ebt_ip6_mt_check(const struct xt_mtchk_param * par)98 static int ebt_ip6_mt_check(const struct xt_mtchk_param *par)
99 {
100 const struct ebt_entry *e = par->entryinfo;
101 struct ebt_ip6_info *info = par->matchinfo;
102
103 if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
104 return -EINVAL;
105 if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
106 return -EINVAL;
107 if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
108 if (info->invflags & EBT_IP6_PROTO)
109 return -EINVAL;
110 if (info->protocol != IPPROTO_TCP &&
111 info->protocol != IPPROTO_UDP &&
112 info->protocol != IPPROTO_UDPLITE &&
113 info->protocol != IPPROTO_SCTP &&
114 info->protocol != IPPROTO_DCCP)
115 return -EINVAL;
116 }
117 if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
118 return -EINVAL;
119 if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
120 return -EINVAL;
121 if (info->bitmask & EBT_IP6_ICMP6) {
122 if ((info->invflags & EBT_IP6_PROTO) ||
123 info->protocol != IPPROTO_ICMPV6)
124 return -EINVAL;
125 if (info->icmpv6_type[0] > info->icmpv6_type[1] ||
126 info->icmpv6_code[0] > info->icmpv6_code[1])
127 return -EINVAL;
128 }
129 return 0;
130 }
131
132 static struct xt_match ebt_ip6_mt_reg __read_mostly = {
133 .name = "ip6",
134 .revision = 0,
135 .family = NFPROTO_BRIDGE,
136 .match = ebt_ip6_mt,
137 .checkentry = ebt_ip6_mt_check,
138 .matchsize = sizeof(struct ebt_ip6_info),
139 .me = THIS_MODULE,
140 };
141
ebt_ip6_init(void)142 static int __init ebt_ip6_init(void)
143 {
144 return xt_register_match(&ebt_ip6_mt_reg);
145 }
146
ebt_ip6_fini(void)147 static void __exit ebt_ip6_fini(void)
148 {
149 xt_unregister_match(&ebt_ip6_mt_reg);
150 }
151
152 module_init(ebt_ip6_init);
153 module_exit(ebt_ip6_fini);
154 MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
155 MODULE_AUTHOR("Kuo-Lang Tseng <kuo-lang.tseng@intel.com>");
156 MODULE_LICENSE("GPL");
157