1 /*
2 * Copyright (C)2003,2004 USAGI/WIDE Project
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Author:
9 * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
10 */
11
12 #include <linux/types.h>
13 #include <linux/timer.h>
14 #include <linux/module.h>
15 #include <linux/netfilter.h>
16 #include <linux/in6.h>
17 #include <linux/icmpv6.h>
18 #include <linux/ipv6.h>
19 #include <net/ipv6.h>
20 #include <net/ip6_checksum.h>
21 #include <linux/seq_file.h>
22 #include <linux/netfilter_ipv6.h>
23 #include <net/netfilter/nf_conntrack_tuple.h>
24 #include <net/netfilter/nf_conntrack_l4proto.h>
25 #include <net/netfilter/nf_conntrack_core.h>
26 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
27 #include <net/netfilter/nf_log.h>
28
29 static unsigned long nf_ct_icmpv6_timeout __read_mostly = 30*HZ;
30
31 static int icmpv6_pkt_to_tuple(const struct sk_buff *skb,
32 unsigned int dataoff,
33 struct nf_conntrack_tuple *tuple)
34 {
35 const struct icmp6hdr *hp;
36 struct icmp6hdr _hdr;
37
38 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
39 if (hp == NULL)
40 return 0;
41 tuple->dst.u.icmp.type = hp->icmp6_type;
42 tuple->src.u.icmp.id = hp->icmp6_identifier;
43 tuple->dst.u.icmp.code = hp->icmp6_code;
44
45 return 1;
46 }
47
48 /* Add 1; spaces filled with 0. */
49 static const u_int8_t invmap[] = {
50 [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
51 [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
52 [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_QUERY + 1,
53 [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_REPLY +1
54 };
55
56 static int icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
57 const struct nf_conntrack_tuple *orig)
58 {
59 int type = orig->dst.u.icmp.type - 128;
60 if (type < 0 || type >= sizeof(invmap) || !invmap[type])
61 return 0;
62
63 tuple->src.u.icmp.id = orig->src.u.icmp.id;
64 tuple->dst.u.icmp.type = invmap[type] - 1;
65 tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
66 return 1;
67 }
68
69 /* Print out the per-protocol part of the tuple. */
70 static int icmpv6_print_tuple(struct seq_file *s,
71 const struct nf_conntrack_tuple *tuple)
72 {
73 return seq_printf(s, "type=%u code=%u id=%u ",
74 tuple->dst.u.icmp.type,
75 tuple->dst.u.icmp.code,
76 ntohs(tuple->src.u.icmp.id));
77 }
78
79 /* Returns verdict for packet, or -1 for invalid. */
80 static int icmpv6_packet(struct nf_conn *ct,
81 const struct sk_buff *skb,
82 unsigned int dataoff,
83 enum ip_conntrack_info ctinfo,
84 int pf,
85 unsigned int hooknum)
86 {
87 /* Try to delete connection immediately after all replies:
88 won't actually vanish as we still have skb, and del_timer
89 means this will only run once even if count hits zero twice
90 (theoretically possible with SMP) */
91 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
92 if (atomic_dec_and_test(&ct->proto.icmp.count)
93 && del_timer(&ct->timeout))
94 ct->timeout.function((unsigned long)ct);
95 } else {
96 atomic_inc(&ct->proto.icmp.count);
97 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
98 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout);
99 }
100
101 return NF_ACCEPT;
102 }
103
104 /* Called when a new connection for this protocol found. */
105 static int icmpv6_new(struct nf_conn *ct,
106 const struct sk_buff *skb,
107 unsigned int dataoff)
108 {
109 static const u_int8_t valid_new[] = {
110 [ICMPV6_ECHO_REQUEST - 128] = 1,
111 [ICMPV6_NI_QUERY - 128] = 1
112 };
113 int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
114
115 if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
116 /* Can't create a new ICMPv6 `conn' with this. */
117 pr_debug("icmpv6: can't create new conn with type %u\n",
118 type + 128);
119 NF_CT_DUMP_TUPLE(&ct->tuplehash[0].tuple);
120 return 0;
121 }
122 atomic_set(&ct->proto.icmp.count, 0);
123 return 1;
124 }
125
126 static int
127 icmpv6_error_message(struct sk_buff *skb,
128 unsigned int icmp6off,
129 enum ip_conntrack_info *ctinfo,
130 unsigned int hooknum)
131 {
132 struct nf_conntrack_tuple intuple, origtuple;
133 const struct nf_conntrack_tuple_hash *h;
134 const struct nf_conntrack_l4proto *inproto;
135
136 NF_CT_ASSERT(skb->nfct == NULL);
137
138 /* Are they talking about one of our connections? */
139 if (!nf_ct_get_tuplepr(skb,
140 skb_network_offset(skb)
141 + sizeof(struct ipv6hdr)
142 + sizeof(struct icmp6hdr),
143 PF_INET6, &origtuple)) {
144 pr_debug("icmpv6_error: Can't get tuple\n");
145 return -NF_ACCEPT;
146 }
147
148 /* rcu_read_lock()ed by nf_hook_slow */
149 inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
150
151 /* Ordinarily, we'd expect the inverted tupleproto, but it's
152 been preserved inside the ICMP. */
153 if (!nf_ct_invert_tuple(&intuple, &origtuple,
154 &nf_conntrack_l3proto_ipv6, inproto)) {
155 pr_debug("icmpv6_error: Can't invert tuple\n");
156 return -NF_ACCEPT;
157 }
158
159 *ctinfo = IP_CT_RELATED;
160
161 h = nf_conntrack_find_get(&intuple);
162 if (!h) {
163 pr_debug("icmpv6_error: no match\n");
164 return -NF_ACCEPT;
165 } else {
166 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
167 *ctinfo += IP_CT_IS_REPLY;
168 }
169
170 /* Update skb to refer to this connection */
171 skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
172 skb->nfctinfo = *ctinfo;
173 return -NF_ACCEPT;
174 }
175
176 static int
177 icmpv6_error(struct sk_buff *skb, unsigned int dataoff,
178 enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum)
179 {
180 const struct icmp6hdr *icmp6h;
181 struct icmp6hdr _ih;
182
183 icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
184 if (icmp6h == NULL) {
185 if (LOG_INVALID(IPPROTO_ICMPV6))
186 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
187 "nf_ct_icmpv6: short packet ");
188 return -NF_ACCEPT;
189 }
190
191 if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
192 nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
193 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
194 "nf_ct_icmpv6: ICMPv6 checksum failed\n");
195 return -NF_ACCEPT;
196 }
197
198 /* is not error message ? */
199 if (icmp6h->icmp6_type >= 128)
200 return NF_ACCEPT;
201
202 return icmpv6_error_message(skb, dataoff, ctinfo, hooknum);
203 }
204
205 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
206
207 #include <linux/netfilter/nfnetlink.h>
208 #include <linux/netfilter/nfnetlink_conntrack.h>
209 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
210 const struct nf_conntrack_tuple *t)
211 {
212 NLA_PUT_BE16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id);
213 NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type);
214 NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code);
215
216 return 0;
217
218 nla_put_failure:
219 return -1;
220 }
221
222 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
223 [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
224 [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
225 [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
226 };
227
228 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
229 struct nf_conntrack_tuple *tuple)
230 {
231 if (!tb[CTA_PROTO_ICMPV6_TYPE]
232 || !tb[CTA_PROTO_ICMPV6_CODE]
233 || !tb[CTA_PROTO_ICMPV6_ID])
234 return -EINVAL;
235
236 tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
237 tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
238 tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
239
240 if (tuple->dst.u.icmp.type < 128
241 || tuple->dst.u.icmp.type - 128 >= sizeof(invmap)
242 || !invmap[tuple->dst.u.icmp.type - 128])
243 return -EINVAL;
244
245 return 0;
246 }
247 #endif
248
249 #ifdef CONFIG_SYSCTL
250 static struct ctl_table_header *icmpv6_sysctl_header;
251 static struct ctl_table icmpv6_sysctl_table[] = {
252 {
253 .procname = "nf_conntrack_icmpv6_timeout",
254 .data = &nf_ct_icmpv6_timeout,
255 .maxlen = sizeof(unsigned int),
256 .mode = 0644,
257 .proc_handler = &proc_dointvec_jiffies,
258 },
259 {
260 .ctl_name = 0
261 }
262 };
263 #endif /* CONFIG_SYSCTL */
264
265 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
266 {
267 .l3proto = PF_INET6,
268 .l4proto = IPPROTO_ICMPV6,
269 .name = "icmpv6",
270 .pkt_to_tuple = icmpv6_pkt_to_tuple,
271 .invert_tuple = icmpv6_invert_tuple,
272 .print_tuple = icmpv6_print_tuple,
273 .packet = icmpv6_packet,
274 .new = icmpv6_new,
275 .error = icmpv6_error,
276 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
277 .tuple_to_nlattr = icmpv6_tuple_to_nlattr,
278 .nlattr_to_tuple = icmpv6_nlattr_to_tuple,
279 .nla_policy = icmpv6_nla_policy,
280 #endif
281 #ifdef CONFIG_SYSCTL
282 .ctl_table_header = &icmpv6_sysctl_header,
283 .ctl_table = icmpv6_sysctl_table,
284 #endif
285 };
286
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