165b256a6fa063943e22617853fe8f59cd572f65
[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 #include <net/netfilter/nf_log.h>
28
29 static unsigned int nf_ct_icmpv6_timeout __read_mostly = 30*HZ;
30
31 static bool 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 false;
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 true;
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_REPLY + 1,
53         [ICMPV6_NI_REPLY - 128]         = ICMPV6_NI_QUERY +1
54 };
55
56 static const u_int8_t noct_valid_new[] = {
57         [ICMPV6_MGM_QUERY - 130] = 1,
58         [ICMPV6_MGM_REPORT -130] = 1,
59         [ICMPV6_MGM_REDUCTION - 130] = 1,
60         [NDISC_ROUTER_SOLICITATION - 130] = 1,
61         [NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
62         [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
63         [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
64         [ICMPV6_MLD2_REPORT - 130] = 1
65 };
66
67 static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
68                                 const struct nf_conntrack_tuple *orig)
69 {
70         int type = orig->dst.u.icmp.type - 128;
71         if (type < 0 || type >= sizeof(invmap) || !invmap[type])
72                 return false;
73
74         tuple->src.u.icmp.id   = orig->src.u.icmp.id;
75         tuple->dst.u.icmp.type = invmap[type] - 1;
76         tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
77         return true;
78 }
79
80 /* Print out the per-protocol part of the tuple. */
81 static int icmpv6_print_tuple(struct seq_file *s,
82                               const struct nf_conntrack_tuple *tuple)
83 {
84         return seq_printf(s, "type=%u code=%u id=%u ",
85                           tuple->dst.u.icmp.type,
86                           tuple->dst.u.icmp.code,
87                           ntohs(tuple->src.u.icmp.id));
88 }
89
90 /* Returns verdict for packet, or -1 for invalid. */
91 static int icmpv6_packet(struct nf_conn *ct,
92                        const struct sk_buff *skb,
93                        unsigned int dataoff,
94                        enum ip_conntrack_info ctinfo,
95                        u_int8_t pf,
96                        unsigned int hooknum)
97 {
98         /* Try to delete connection immediately after all replies:
99            won't actually vanish as we still have skb, and del_timer
100            means this will only run once even if count hits zero twice
101            (theoretically possible with SMP) */
102         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
103                 if (atomic_dec_and_test(&ct->proto.icmp.count))
104                         nf_ct_kill_acct(ct, ctinfo, skb);
105         } else {
106                 atomic_inc(&ct->proto.icmp.count);
107                 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, ct);
108                 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout);
109         }
110
111         return NF_ACCEPT;
112 }
113
114 /* Called when a new connection for this protocol found. */
115 static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
116                        unsigned int dataoff)
117 {
118         static const u_int8_t valid_new[] = {
119                 [ICMPV6_ECHO_REQUEST - 128] = 1,
120                 [ICMPV6_NI_QUERY - 128] = 1
121         };
122         int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
123
124         if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
125                 /* Can't create a new ICMPv6 `conn' with this. */
126                 pr_debug("icmpv6: can't create new conn with type %u\n",
127                          type + 128);
128                 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
129                 if (LOG_INVALID(nf_ct_net(ct), IPPROTO_ICMPV6))
130                         nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
131                                       "nf_ct_icmpv6: invalid new with type %d ",
132                                       type + 128);
133                 return false;
134         }
135         atomic_set(&ct->proto.icmp.count, 0);
136         return true;
137 }
138
139 static int
140 icmpv6_error_message(struct net *net,
141                      struct sk_buff *skb,
142                      unsigned int icmp6off,
143                      enum ip_conntrack_info *ctinfo,
144                      unsigned int hooknum)
145 {
146         struct nf_conntrack_tuple intuple, origtuple;
147         const struct nf_conntrack_tuple_hash *h;
148         const struct nf_conntrack_l4proto *inproto;
149
150         NF_CT_ASSERT(skb->nfct == NULL);
151
152         /* Are they talking about one of our connections? */
153         if (!nf_ct_get_tuplepr(skb,
154                                skb_network_offset(skb)
155                                 + sizeof(struct ipv6hdr)
156                                 + sizeof(struct icmp6hdr),
157                                PF_INET6, &origtuple)) {
158                 pr_debug("icmpv6_error: Can't get tuple\n");
159                 return -NF_ACCEPT;
160         }
161
162         /* rcu_read_lock()ed by nf_hook_slow */
163         inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
164
165         /* Ordinarily, we'd expect the inverted tupleproto, but it's
166            been preserved inside the ICMP. */
167         if (!nf_ct_invert_tuple(&intuple, &origtuple,
168                                 &nf_conntrack_l3proto_ipv6, inproto)) {
169                 pr_debug("icmpv6_error: Can't invert tuple\n");
170                 return -NF_ACCEPT;
171         }
172
173         *ctinfo = IP_CT_RELATED;
174
175         h = nf_conntrack_find_get(net, &intuple);
176         if (!h) {
177                 pr_debug("icmpv6_error: no match\n");
178                 return -NF_ACCEPT;
179         } else {
180                 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
181                         *ctinfo += IP_CT_IS_REPLY;
182         }
183
184         /* Update skb to refer to this connection */
185         skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
186         skb->nfctinfo = *ctinfo;
187         return -NF_ACCEPT;
188 }
189
190 static int
191 icmpv6_error(struct net *net, struct sk_buff *skb, unsigned int dataoff,
192              enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
193 {
194         const struct icmp6hdr *icmp6h;
195         struct icmp6hdr _ih;
196         int type;
197
198         icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
199         if (icmp6h == NULL) {
200                 if (LOG_INVALID(net, IPPROTO_ICMPV6))
201                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
202                               "nf_ct_icmpv6: short packet ");
203                 return -NF_ACCEPT;
204         }
205
206         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
207             nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
208                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
209                               "nf_ct_icmpv6: ICMPv6 checksum failed\n");
210                 return -NF_ACCEPT;
211         }
212
213         type = icmp6h->icmp6_type - 130;
214         if (type >= 0 && type < sizeof(noct_valid_new) &&
215             noct_valid_new[type]) {
216                 skb->nfct = &nf_conntrack_untracked.ct_general;
217                 skb->nfctinfo = IP_CT_NEW;
218                 nf_conntrack_get(skb->nfct);
219                 return NF_ACCEPT;
220         }
221
222         /* is not error message ? */
223         if (icmp6h->icmp6_type >= 128)
224                 return NF_ACCEPT;
225
226         return icmpv6_error_message(net, skb, dataoff, ctinfo, hooknum);
227 }
228
229 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
230
231 #include <linux/netfilter/nfnetlink.h>
232 #include <linux/netfilter/nfnetlink_conntrack.h>
233 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
234                                   const struct nf_conntrack_tuple *t)
235 {
236         NLA_PUT_BE16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id);
237         NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type);
238         NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code);
239
240         return 0;
241
242 nla_put_failure:
243         return -1;
244 }
245
246 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
247         [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
248         [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
249         [CTA_PROTO_ICMPV6_ID]   = { .type = NLA_U16 },
250 };
251
252 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
253                                 struct nf_conntrack_tuple *tuple)
254 {
255         if (!tb[CTA_PROTO_ICMPV6_TYPE]
256             || !tb[CTA_PROTO_ICMPV6_CODE]
257             || !tb[CTA_PROTO_ICMPV6_ID])
258                 return -EINVAL;
259
260         tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
261         tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
262         tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
263
264         if (tuple->dst.u.icmp.type < 128
265             || tuple->dst.u.icmp.type - 128 >= sizeof(invmap)
266             || !invmap[tuple->dst.u.icmp.type - 128])
267                 return -EINVAL;
268
269         return 0;
270 }
271 #endif
272
273 #ifdef CONFIG_SYSCTL
274 static struct ctl_table_header *icmpv6_sysctl_header;
275 static struct ctl_table icmpv6_sysctl_table[] = {
276         {
277                 .procname       = "nf_conntrack_icmpv6_timeout",
278                 .data           = &nf_ct_icmpv6_timeout,
279                 .maxlen         = sizeof(unsigned int),
280                 .mode           = 0644,
281                 .proc_handler   = proc_dointvec_jiffies,
282         },
283         {
284                 .ctl_name       = 0
285         }
286 };
287 #endif /* CONFIG_SYSCTL */
288
289 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
290 {
291         .l3proto                = PF_INET6,
292         .l4proto                = IPPROTO_ICMPV6,
293         .name                   = "icmpv6",
294         .pkt_to_tuple           = icmpv6_pkt_to_tuple,
295         .invert_tuple           = icmpv6_invert_tuple,
296         .print_tuple            = icmpv6_print_tuple,
297         .packet                 = icmpv6_packet,
298         .new                    = icmpv6_new,
299         .error                  = icmpv6_error,
300 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
301         .tuple_to_nlattr        = icmpv6_tuple_to_nlattr,
302         .nlattr_to_tuple        = icmpv6_nlattr_to_tuple,
303         .nla_policy             = icmpv6_nla_policy,
304 #endif
305 #ifdef CONFIG_SYSCTL
306         .ctl_table_header       = &icmpv6_sysctl_header,
307         .ctl_table              = icmpv6_sysctl_table,
308 #endif
309 };