netfilter: conntrack: simplify event caching system
[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_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout);
108         }
109
110         return NF_ACCEPT;
111 }
112
113 /* Called when a new connection for this protocol found. */
114 static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
115                        unsigned int dataoff)
116 {
117         static const u_int8_t valid_new[] = {
118                 [ICMPV6_ECHO_REQUEST - 128] = 1,
119                 [ICMPV6_NI_QUERY - 128] = 1
120         };
121         int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
122
123         if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
124                 /* Can't create a new ICMPv6 `conn' with this. */
125                 pr_debug("icmpv6: can't create new conn with type %u\n",
126                          type + 128);
127                 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
128                 if (LOG_INVALID(nf_ct_net(ct), IPPROTO_ICMPV6))
129                         nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
130                                       "nf_ct_icmpv6: invalid new with type %d ",
131                                       type + 128);
132                 return false;
133         }
134         atomic_set(&ct->proto.icmp.count, 0);
135         return true;
136 }
137
138 static int
139 icmpv6_error_message(struct net *net,
140                      struct sk_buff *skb,
141                      unsigned int icmp6off,
142                      enum ip_conntrack_info *ctinfo,
143                      unsigned int hooknum)
144 {
145         struct nf_conntrack_tuple intuple, origtuple;
146         const struct nf_conntrack_tuple_hash *h;
147         const struct nf_conntrack_l4proto *inproto;
148
149         NF_CT_ASSERT(skb->nfct == NULL);
150
151         /* Are they talking about one of our connections? */
152         if (!nf_ct_get_tuplepr(skb,
153                                skb_network_offset(skb)
154                                 + sizeof(struct ipv6hdr)
155                                 + sizeof(struct icmp6hdr),
156                                PF_INET6, &origtuple)) {
157                 pr_debug("icmpv6_error: Can't get tuple\n");
158                 return -NF_ACCEPT;
159         }
160
161         /* rcu_read_lock()ed by nf_hook_slow */
162         inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
163
164         /* Ordinarily, we'd expect the inverted tupleproto, but it's
165            been preserved inside the ICMP. */
166         if (!nf_ct_invert_tuple(&intuple, &origtuple,
167                                 &nf_conntrack_l3proto_ipv6, inproto)) {
168                 pr_debug("icmpv6_error: Can't invert tuple\n");
169                 return -NF_ACCEPT;
170         }
171
172         *ctinfo = IP_CT_RELATED;
173
174         h = nf_conntrack_find_get(net, &intuple);
175         if (!h) {
176                 pr_debug("icmpv6_error: no match\n");
177                 return -NF_ACCEPT;
178         } else {
179                 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
180                         *ctinfo += IP_CT_IS_REPLY;
181         }
182
183         /* Update skb to refer to this connection */
184         skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
185         skb->nfctinfo = *ctinfo;
186         return -NF_ACCEPT;
187 }
188
189 static int
190 icmpv6_error(struct net *net, struct sk_buff *skb, unsigned int dataoff,
191              enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
192 {
193         const struct icmp6hdr *icmp6h;
194         struct icmp6hdr _ih;
195         int type;
196
197         icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
198         if (icmp6h == NULL) {
199                 if (LOG_INVALID(net, IPPROTO_ICMPV6))
200                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
201                               "nf_ct_icmpv6: short packet ");
202                 return -NF_ACCEPT;
203         }
204
205         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
206             nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
207                 if (LOG_INVALID(net, IPPROTO_ICMPV6))
208                         nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
209                                       "nf_ct_icmpv6: ICMPv6 checksum failed ");
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
272 static int icmpv6_nlattr_tuple_size(void)
273 {
274         return nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
275 }
276 #endif
277
278 #ifdef CONFIG_SYSCTL
279 static struct ctl_table_header *icmpv6_sysctl_header;
280 static struct ctl_table icmpv6_sysctl_table[] = {
281         {
282                 .procname       = "nf_conntrack_icmpv6_timeout",
283                 .data           = &nf_ct_icmpv6_timeout,
284                 .maxlen         = sizeof(unsigned int),
285                 .mode           = 0644,
286                 .proc_handler   = proc_dointvec_jiffies,
287         },
288         {
289                 .ctl_name       = 0
290         }
291 };
292 #endif /* CONFIG_SYSCTL */
293
294 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
295 {
296         .l3proto                = PF_INET6,
297         .l4proto                = IPPROTO_ICMPV6,
298         .name                   = "icmpv6",
299         .pkt_to_tuple           = icmpv6_pkt_to_tuple,
300         .invert_tuple           = icmpv6_invert_tuple,
301         .print_tuple            = icmpv6_print_tuple,
302         .packet                 = icmpv6_packet,
303         .new                    = icmpv6_new,
304         .error                  = icmpv6_error,
305 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
306         .tuple_to_nlattr        = icmpv6_tuple_to_nlattr,
307         .nlattr_tuple_size      = icmpv6_nlattr_tuple_size,
308         .nlattr_to_tuple        = icmpv6_nlattr_to_tuple,
309         .nla_policy             = icmpv6_nla_policy,
310 #endif
311 #ifdef CONFIG_SYSCTL
312         .ctl_table_header       = &icmpv6_sysctl_header,
313         .ctl_table              = icmpv6_sysctl_table,
314 #endif
315 };