9defc7e14554b4cc431deb5223764cb8a4deebe2
[linux-2.6.git] / net / ipv6 / netfilter / nf_conntrack_proto_icmpv6.c
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
28 static unsigned long nf_ct_icmpv6_timeout __read_mostly = 30*HZ;
29
30 static int icmpv6_pkt_to_tuple(const struct sk_buff *skb,
31                                unsigned int dataoff,
32                                struct nf_conntrack_tuple *tuple)
33 {
34         struct icmp6hdr _hdr, *hp;
35
36         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
37         if (hp == NULL)
38                 return 0;
39         tuple->dst.u.icmp.type = hp->icmp6_type;
40         tuple->src.u.icmp.id = hp->icmp6_identifier;
41         tuple->dst.u.icmp.code = hp->icmp6_code;
42
43         return 1;
44 }
45
46 /* Add 1; spaces filled with 0. */
47 static u_int8_t invmap[] = {
48         [ICMPV6_ECHO_REQUEST - 128]     = ICMPV6_ECHO_REPLY + 1,
49         [ICMPV6_ECHO_REPLY - 128]       = ICMPV6_ECHO_REQUEST + 1,
50         [ICMPV6_NI_QUERY - 128]         = ICMPV6_NI_QUERY + 1,
51         [ICMPV6_NI_REPLY - 128]         = ICMPV6_NI_REPLY +1
52 };
53
54 static int icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
55                                const struct nf_conntrack_tuple *orig)
56 {
57         int type = orig->dst.u.icmp.type - 128;
58         if (type < 0 || type >= sizeof(invmap) || !invmap[type])
59                 return 0;
60
61         tuple->src.u.icmp.id   = orig->src.u.icmp.id;
62         tuple->dst.u.icmp.type = invmap[type] - 1;
63         tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
64         return 1;
65 }
66
67 /* Print out the per-protocol part of the tuple. */
68 static int icmpv6_print_tuple(struct seq_file *s,
69                               const struct nf_conntrack_tuple *tuple)
70 {
71         return seq_printf(s, "type=%u code=%u id=%u ",
72                           tuple->dst.u.icmp.type,
73                           tuple->dst.u.icmp.code,
74                           ntohs(tuple->src.u.icmp.id));
75 }
76
77 /* Print out the private part of the conntrack. */
78 static int icmpv6_print_conntrack(struct seq_file *s,
79                                   const struct nf_conn *conntrack)
80 {
81         return 0;
82 }
83
84 /* Returns verdict for packet, or -1 for invalid. */
85 static int icmpv6_packet(struct nf_conn *ct,
86                        const struct sk_buff *skb,
87                        unsigned int dataoff,
88                        enum ip_conntrack_info ctinfo,
89                        int pf,
90                        unsigned int hooknum)
91 {
92         /* Try to delete connection immediately after all replies:
93            won't actually vanish as we still have skb, and del_timer
94            means this will only run once even if count hits zero twice
95            (theoretically possible with SMP) */
96         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
97                 if (atomic_dec_and_test(&ct->proto.icmp.count)
98                     && del_timer(&ct->timeout))
99                         ct->timeout.function((unsigned long)ct);
100         } else {
101                 atomic_inc(&ct->proto.icmp.count);
102                 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
103                 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout);
104         }
105
106         return NF_ACCEPT;
107 }
108
109 /* Called when a new connection for this protocol found. */
110 static int icmpv6_new(struct nf_conn *conntrack,
111                       const struct sk_buff *skb,
112                       unsigned int dataoff)
113 {
114         static u_int8_t valid_new[] = {
115                 [ICMPV6_ECHO_REQUEST - 128] = 1,
116                 [ICMPV6_NI_QUERY - 128] = 1
117         };
118         int type = conntrack->tuplehash[0].tuple.dst.u.icmp.type - 128;
119
120         if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
121                 /* Can't create a new ICMPv6 `conn' with this. */
122                 pr_debug("icmpv6: can't create new conn with type %u\n",
123                          type + 128);
124                 NF_CT_DUMP_TUPLE(&conntrack->tuplehash[0].tuple);
125                 return 0;
126         }
127         atomic_set(&conntrack->proto.icmp.count, 0);
128         return 1;
129 }
130
131 static int
132 icmpv6_error_message(struct sk_buff *skb,
133                      unsigned int icmp6off,
134                      enum ip_conntrack_info *ctinfo,
135                      unsigned int hooknum)
136 {
137         struct nf_conntrack_tuple intuple, origtuple;
138         struct nf_conntrack_tuple_hash *h;
139         struct icmp6hdr _hdr, *hp;
140         unsigned int inip6off;
141         struct nf_conntrack_l4proto *inproto;
142         u_int8_t inprotonum;
143         unsigned int inprotoff;
144
145         NF_CT_ASSERT(skb->nfct == NULL);
146
147         hp = skb_header_pointer(skb, icmp6off, sizeof(_hdr), &_hdr);
148         if (hp == NULL) {
149                 pr_debug("icmpv6_error: Can't get ICMPv6 hdr.\n");
150                 return -NF_ACCEPT;
151         }
152
153         inip6off = icmp6off + sizeof(_hdr);
154         if (skb_copy_bits(skb, inip6off+offsetof(struct ipv6hdr, nexthdr),
155                           &inprotonum, sizeof(inprotonum)) != 0) {
156                 pr_debug("icmpv6_error: Can't get nexthdr in inner IPv6 "
157                          "header.\n");
158                 return -NF_ACCEPT;
159         }
160         inprotoff = nf_ct_ipv6_skip_exthdr(skb,
161                                            inip6off + sizeof(struct ipv6hdr),
162                                            &inprotonum,
163                                            skb->len - inip6off
164                                                     - sizeof(struct ipv6hdr));
165
166         if ((inprotoff > skb->len) || (inprotonum == NEXTHDR_FRAGMENT)) {
167                 pr_debug("icmpv6_error: Can't get protocol header in ICMPv6 "
168                          "payload.\n");
169                 return -NF_ACCEPT;
170         }
171
172         /* rcu_read_lock()ed by nf_hook_slow */
173         inproto = __nf_ct_l4proto_find(PF_INET6, inprotonum);
174
175         /* Are they talking about one of our connections? */
176         if (!nf_ct_get_tuple(skb, inip6off, inprotoff, PF_INET6, inprotonum,
177                              &origtuple, &nf_conntrack_l3proto_ipv6, inproto)) {
178                 pr_debug("icmpv6_error: Can't get tuple\n");
179                 return -NF_ACCEPT;
180         }
181
182         /* Ordinarily, we'd expect the inverted tupleproto, but it's
183            been preserved inside the ICMP. */
184         if (!nf_ct_invert_tuple(&intuple, &origtuple,
185                                 &nf_conntrack_l3proto_ipv6, inproto)) {
186                 pr_debug("icmpv6_error: Can't invert tuple\n");
187                 return -NF_ACCEPT;
188         }
189
190         *ctinfo = IP_CT_RELATED;
191
192         h = nf_conntrack_find_get(&intuple);
193         if (!h) {
194                 pr_debug("icmpv6_error: no match\n");
195                 return -NF_ACCEPT;
196         } else {
197                 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
198                         *ctinfo += IP_CT_IS_REPLY;
199         }
200
201         /* Update skb to refer to this connection */
202         skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
203         skb->nfctinfo = *ctinfo;
204         return -NF_ACCEPT;
205 }
206
207 static int
208 icmpv6_error(struct sk_buff *skb, unsigned int dataoff,
209              enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum)
210 {
211         struct icmp6hdr _ih, *icmp6h;
212
213         icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
214         if (icmp6h == NULL) {
215                 if (LOG_INVALID(IPPROTO_ICMPV6))
216                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
217                               "nf_ct_icmpv6: short packet ");
218                 return -NF_ACCEPT;
219         }
220
221         if (nf_conntrack_checksum && hooknum == NF_IP6_PRE_ROUTING &&
222             nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
223                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
224                               "nf_ct_icmpv6: ICMPv6 checksum failed\n");
225                 return -NF_ACCEPT;
226         }
227
228         /* is not error message ? */
229         if (icmp6h->icmp6_type >= 128)
230                 return NF_ACCEPT;
231
232         return icmpv6_error_message(skb, dataoff, ctinfo, hooknum);
233 }
234
235 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
236
237 #include <linux/netfilter/nfnetlink.h>
238 #include <linux/netfilter/nfnetlink_conntrack.h>
239 static int icmpv6_tuple_to_nfattr(struct sk_buff *skb,
240                                   const struct nf_conntrack_tuple *t)
241 {
242         NFA_PUT(skb, CTA_PROTO_ICMPV6_ID, sizeof(u_int16_t),
243                 &t->src.u.icmp.id);
244         NFA_PUT(skb, CTA_PROTO_ICMPV6_TYPE, sizeof(u_int8_t),
245                 &t->dst.u.icmp.type);
246         NFA_PUT(skb, CTA_PROTO_ICMPV6_CODE, sizeof(u_int8_t),
247                 &t->dst.u.icmp.code);
248
249         return 0;
250
251 nfattr_failure:
252         return -1;
253 }
254
255 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
256         [CTA_PROTO_ICMPV6_TYPE-1] = sizeof(u_int8_t),
257         [CTA_PROTO_ICMPV6_CODE-1] = sizeof(u_int8_t),
258         [CTA_PROTO_ICMPV6_ID-1]   = sizeof(u_int16_t)
259 };
260
261 static int icmpv6_nfattr_to_tuple(struct nfattr *tb[],
262                                 struct nf_conntrack_tuple *tuple)
263 {
264         if (!tb[CTA_PROTO_ICMPV6_TYPE-1]
265             || !tb[CTA_PROTO_ICMPV6_CODE-1]
266             || !tb[CTA_PROTO_ICMPV6_ID-1])
267                 return -EINVAL;
268
269         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
270                 return -EINVAL;
271
272         tuple->dst.u.icmp.type =
273                         *(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_TYPE-1]);
274         tuple->dst.u.icmp.code =
275                         *(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_CODE-1]);
276         tuple->src.u.icmp.id =
277                         *(__be16 *)NFA_DATA(tb[CTA_PROTO_ICMPV6_ID-1]);
278
279         if (tuple->dst.u.icmp.type < 128
280             || tuple->dst.u.icmp.type - 128 >= sizeof(invmap)
281             || !invmap[tuple->dst.u.icmp.type - 128])
282                 return -EINVAL;
283
284         return 0;
285 }
286 #endif
287
288 #ifdef CONFIG_SYSCTL
289 static struct ctl_table_header *icmpv6_sysctl_header;
290 static struct ctl_table icmpv6_sysctl_table[] = {
291         {
292                 .ctl_name       = NET_NF_CONNTRACK_ICMPV6_TIMEOUT,
293                 .procname       = "nf_conntrack_icmpv6_timeout",
294                 .data           = &nf_ct_icmpv6_timeout,
295                 .maxlen         = sizeof(unsigned int),
296                 .mode           = 0644,
297                 .proc_handler   = &proc_dointvec_jiffies,
298         },
299         {
300                 .ctl_name       = 0
301         }
302 };
303 #endif /* CONFIG_SYSCTL */
304
305 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 =
306 {
307         .l3proto                = PF_INET6,
308         .l4proto                = IPPROTO_ICMPV6,
309         .name                   = "icmpv6",
310         .pkt_to_tuple           = icmpv6_pkt_to_tuple,
311         .invert_tuple           = icmpv6_invert_tuple,
312         .print_tuple            = icmpv6_print_tuple,
313         .print_conntrack        = icmpv6_print_conntrack,
314         .packet                 = icmpv6_packet,
315         .new                    = icmpv6_new,
316         .error                  = icmpv6_error,
317 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
318         .tuple_to_nfattr        = icmpv6_tuple_to_nfattr,
319         .nfattr_to_tuple        = icmpv6_nfattr_to_tuple,
320 #endif
321 #ifdef CONFIG_SYSCTL
322         .ctl_table_header       = &icmpv6_sysctl_header,
323         .ctl_table              = icmpv6_sysctl_table,
324 #endif
325 };
326
327 EXPORT_SYMBOL(nf_conntrack_l4proto_icmpv6);