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
25union pkthdr {
26	struct {
27		__be16 src;
28		__be16 dst;
29	} tcpudphdr;
30	struct {
31		u8 type;
32		u8 code;
33	} icmphdr;
34};
35
36static bool
37ebt_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 ((info->bitmask & EBT_IP6_SOURCE &&
52	    FWINV(ipv6_masked_addr_cmp(&ih6->saddr, &info->smsk,
53				       &info->saddr), EBT_IP6_SOURCE)) ||
54	    (info->bitmask & EBT_IP6_DEST &&
55	    FWINV(ipv6_masked_addr_cmp(&ih6->daddr, &info->dmsk,
56				       &info->daddr), EBT_IP6_DEST)))
57		return false;
58	if (info->bitmask & EBT_IP6_PROTO) {
59		uint8_t nexthdr = ih6->nexthdr;
60		__be16 frag_off;
61		int offset_ph;
62
63		offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr, &frag_off);
64		if (offset_ph == -1)
65			return false;
66		if (FWINV(info->protocol != nexthdr, EBT_IP6_PROTO))
67			return false;
68		if (!(info->bitmask & ( EBT_IP6_DPORT |
69					EBT_IP6_SPORT | EBT_IP6_ICMP6)))
70			return true;
71
72		/* min icmpv6 headersize is 4, so sizeof(_pkthdr) is ok. */
73		pptr = skb_header_pointer(skb, offset_ph, sizeof(_pkthdr),
74					  &_pkthdr);
75		if (pptr == NULL)
76			return false;
77		if (info->bitmask & EBT_IP6_DPORT) {
78			u16 dst = ntohs(pptr->tcpudphdr.dst);
79			if (FWINV(dst < info->dport[0] ||
80				  dst > info->dport[1], EBT_IP6_DPORT))
81				return false;
82		}
83		if (info->bitmask & EBT_IP6_SPORT) {
84			u16 src = ntohs(pptr->tcpudphdr.src);
85			if (FWINV(src < info->sport[0] ||
86				  src > info->sport[1], EBT_IP6_SPORT))
87			return false;
88		}
89		if ((info->bitmask & EBT_IP6_ICMP6) &&
90		     FWINV(pptr->icmphdr.type < info->icmpv6_type[0] ||
91			   pptr->icmphdr.type > info->icmpv6_type[1] ||
92			   pptr->icmphdr.code < info->icmpv6_code[0] ||
93			   pptr->icmphdr.code > info->icmpv6_code[1],
94							EBT_IP6_ICMP6))
95			return false;
96	}
97	return true;
98}
99
100static int ebt_ip6_mt_check(const struct xt_mtchk_param *par)
101{
102	const struct ebt_entry *e = par->entryinfo;
103	struct ebt_ip6_info *info = par->matchinfo;
104
105	if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
106		return -EINVAL;
107	if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
108		return -EINVAL;
109	if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
110		if (info->invflags & EBT_IP6_PROTO)
111			return -EINVAL;
112		if (info->protocol != IPPROTO_TCP &&
113		    info->protocol != IPPROTO_UDP &&
114		    info->protocol != IPPROTO_UDPLITE &&
115		    info->protocol != IPPROTO_SCTP &&
116		    info->protocol != IPPROTO_DCCP)
117			return -EINVAL;
118	}
119	if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
120		return -EINVAL;
121	if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
122		return -EINVAL;
123	if (info->bitmask & EBT_IP6_ICMP6) {
124		if ((info->invflags & EBT_IP6_PROTO) ||
125		     info->protocol != IPPROTO_ICMPV6)
126			return -EINVAL;
127		if (info->icmpv6_type[0] > info->icmpv6_type[1] ||
128		    info->icmpv6_code[0] > info->icmpv6_code[1])
129			return -EINVAL;
130	}
131	return 0;
132}
133
134static struct xt_match ebt_ip6_mt_reg __read_mostly = {
135	.name		= "ip6",
136	.revision	= 0,
137	.family		= NFPROTO_BRIDGE,
138	.match		= ebt_ip6_mt,
139	.checkentry	= ebt_ip6_mt_check,
140	.matchsize	= sizeof(struct ebt_ip6_info),
141	.me		= THIS_MODULE,
142};
143
144static int __init ebt_ip6_init(void)
145{
146	return xt_register_match(&ebt_ip6_mt_reg);
147}
148
149static void __exit ebt_ip6_fini(void)
150{
151	xt_unregister_match(&ebt_ip6_mt_reg);
152}
153
154module_init(ebt_ip6_init);
155module_exit(ebt_ip6_fini);
156MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
157MODULE_AUTHOR("Kuo-Lang Tseng <kuo-lang.tseng@intel.com>");
158MODULE_LICENSE("GPL");
159