1df3c8b6bf4723668e6b8c43666b3e31f4583fd8
[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/nf_conntrack_zones.h>
27 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
28 #include <net/netfilter/nf_log.h>
29
30 static unsigned int nf_ct_icmpv6_timeout __read_mostly = 30*HZ;
31
32 static bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
33                                 unsigned int dataoff,
34                                 struct nf_conntrack_tuple *tuple)
35 {
36         const struct icmp6hdr *hp;
37         struct icmp6hdr _hdr;
38
39         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
40         if (hp == NULL)
41                 return false;
42         tuple->dst.u.icmp.type = hp->icmp6_type;
43         tuple->src.u.icmp.id = hp->icmp6_identifier;
44         tuple->dst.u.icmp.code = hp->icmp6_code;
45
46         return true;
47 }
48
49 /* Add 1; spaces filled with 0. */
50 static const u_int8_t invmap[] = {
51         [ICMPV6_ECHO_REQUEST - 128]     = ICMPV6_ECHO_REPLY + 1,
52         [ICMPV6_ECHO_REPLY - 128]       = ICMPV6_ECHO_REQUEST + 1,
53         [ICMPV6_NI_QUERY - 128]         = ICMPV6_NI_REPLY + 1,
54         [ICMPV6_NI_REPLY - 128]         = ICMPV6_NI_QUERY +1
55 };
56
57 static const u_int8_t noct_valid_new[] = {
58         [ICMPV6_MGM_QUERY - 130] = 1,
59         [ICMPV6_MGM_REPORT -130] = 1,
60         [ICMPV6_MGM_REDUCTION - 130] = 1,
61         [NDISC_ROUTER_SOLICITATION - 130] = 1,
62         [NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
63         [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
64         [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
65         [ICMPV6_MLD2_REPORT - 130] = 1
66 };
67
68 static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
69                                 const struct nf_conntrack_tuple *orig)
70 {
71         int type = orig->dst.u.icmp.type - 128;
72         if (type < 0 || type >= sizeof(invmap) || !invmap[type])
73                 return false;
74
75         tuple->src.u.icmp.id   = orig->src.u.icmp.id;
76         tuple->dst.u.icmp.type = invmap[type] - 1;
77         tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
78         return true;
79 }
80
81 /* Print out the per-protocol part of the tuple. */
82 static int icmpv6_print_tuple(struct seq_file *s,
83                               const struct nf_conntrack_tuple *tuple)
84 {
85         return seq_printf(s, "type=%u code=%u id=%u ",
86                           tuple->dst.u.icmp.type,
87                           tuple->dst.u.icmp.code,
88                           ntohs(tuple->src.u.icmp.id));
89 }
90
91 /* Returns verdict for packet, or -1 for invalid. */
92 static int icmpv6_packet(struct nf_conn *ct,
93                        const struct sk_buff *skb,
94                        unsigned int dataoff,
95                        enum ip_conntrack_info ctinfo,
96                        u_int8_t pf,
97                        unsigned int hooknum)
98 {
99         /* Do not immediately delete the connection after the first
100            successful reply to avoid excessive conntrackd traffic
101            and also to handle correctly ICMP echo reply duplicates. */
102         nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout);
103
104         return NF_ACCEPT;
105 }
106
107 /* Called when a new connection for this protocol found. */
108 static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
109                        unsigned int dataoff)
110 {
111         static const u_int8_t valid_new[] = {
112                 [ICMPV6_ECHO_REQUEST - 128] = 1,
113                 [ICMPV6_NI_QUERY - 128] = 1
114         };
115         int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
116
117         if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
118                 /* Can't create a new ICMPv6 `conn' with this. */
119                 pr_debug("icmpv6: can't create new conn with type %u\n",
120                          type + 128);
121                 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
122                 if (LOG_INVALID(nf_ct_net(ct), IPPROTO_ICMPV6))
123                         nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
124                                       "nf_ct_icmpv6: invalid new with type %d ",
125                                       type + 128);
126                 return false;
127         }
128         return true;
129 }
130
131 static int
132 icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
133                      struct sk_buff *skb,
134                      unsigned int icmp6off,
135                      enum ip_conntrack_info *ctinfo,
136                      unsigned int hooknum)
137 {
138         struct nf_conntrack_tuple intuple, origtuple;
139         const struct nf_conntrack_tuple_hash *h;
140         const struct nf_conntrack_l4proto *inproto;
141         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
142
143         NF_CT_ASSERT(skb->nfct == NULL);
144
145         /* Are they talking about one of our connections? */
146         if (!nf_ct_get_tuplepr(skb,
147                                skb_network_offset(skb)
148                                 + sizeof(struct ipv6hdr)
149                                 + sizeof(struct icmp6hdr),
150                                PF_INET6, &origtuple)) {
151                 pr_debug("icmpv6_error: Can't get tuple\n");
152                 return -NF_ACCEPT;
153         }
154
155         /* rcu_read_lock()ed by nf_hook_slow */
156         inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
157
158         /* Ordinarily, we'd expect the inverted tupleproto, but it's
159            been preserved inside the ICMP. */
160         if (!nf_ct_invert_tuple(&intuple, &origtuple,
161                                 &nf_conntrack_l3proto_ipv6, inproto)) {
162                 pr_debug("icmpv6_error: Can't invert tuple\n");
163                 return -NF_ACCEPT;
164         }
165
166         *ctinfo = IP_CT_RELATED;
167
168         h = nf_conntrack_find_get(net, zone, &intuple);
169         if (!h) {
170                 pr_debug("icmpv6_error: no match\n");
171                 return -NF_ACCEPT;
172         } else {
173                 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
174                         *ctinfo += IP_CT_IS_REPLY;
175         }
176
177         /* Update skb to refer to this connection */
178         skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
179         skb->nfctinfo = *ctinfo;
180         return -NF_ACCEPT;
181 }
182
183 static int
184 icmpv6_error(struct net *net, struct nf_conn *tmpl,
185              struct sk_buff *skb, unsigned int dataoff,
186              enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
187 {
188         const struct icmp6hdr *icmp6h;
189         struct icmp6hdr _ih;
190         int type;
191
192         icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
193         if (icmp6h == NULL) {
194                 if (LOG_INVALID(net, IPPROTO_ICMPV6))
195                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
196                               "nf_ct_icmpv6: short packet ");
197                 return -NF_ACCEPT;
198         }
199
200         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
201             nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
202                 if (LOG_INVALID(net, IPPROTO_ICMPV6))
203                         nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
204                                       "nf_ct_icmpv6: ICMPv6 checksum failed ");
205                 return -NF_ACCEPT;
206         }
207
208         type = icmp6h->icmp6_type - 130;
209         if (type >= 0 && type < sizeof(noct_valid_new) &&
210             noct_valid_new[type]) {
211                 skb->nfct = &nf_ct_untracked_get()->ct_general;
212                 skb->nfctinfo = IP_CT_NEW;
213                 nf_conntrack_get(skb->nfct);
214                 return NF_ACCEPT;
215         }
216
217         /* is not error message ? */
218         if (icmp6h->icmp6_type >= 128)
219                 return NF_ACCEPT;
220
221         return icmpv6_error_message(net, tmpl, skb, dataoff, ctinfo, hooknum);
222 }
223
224 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
225
226 #include <linux/netfilter/nfnetlink.h>
227 #include <linux/netfilter/nfnetlink_conntrack.h>
228 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
229                                   const struct nf_conntrack_tuple *t)
230 {
231         NLA_PUT_BE16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id);
232         NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type);
233         NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code);
234
235         return 0;
236
237 nla_put_failure:
238         return -1;
239 }
240
241 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
242         [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
243         [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
244         [CTA_PROTO_ICMPV6_ID]   = { .type = NLA_U16 },
245 };
246
247 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
248                                 struct nf_conntrack_tuple *tuple)
249 {
250         if (!tb[CTA_PROTO_ICMPV6_TYPE] ||
251             !tb[CTA_PROTO_ICMPV6_CODE] ||
252             !tb[CTA_PROTO_ICMPV6_ID])
253                 return -EINVAL;
254
255         tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
256         tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
257         tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
258
259         if (tuple->dst.u.icmp.type < 128 ||
260             tuple->dst.u.icmp.type - 128 >= sizeof(invmap) ||
261             !invmap[tuple->dst.u.icmp.type - 128])
262                 return -EINVAL;
263
264         return 0;
265 }
266
267 static int icmpv6_nlattr_tuple_size(void)
268 {
269         return nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
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 };
285 #endif /* CONFIG_SYSCTL */
286
287 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
288 {
289         .l3proto                = PF_INET6,
290         .l4proto                = IPPROTO_ICMPV6,
291         .name                   = "icmpv6",
292         .pkt_to_tuple           = icmpv6_pkt_to_tuple,
293         .invert_tuple           = icmpv6_invert_tuple,
294         .print_tuple            = icmpv6_print_tuple,
295         .packet                 = icmpv6_packet,
296         .new                    = icmpv6_new,
297         .error                  = icmpv6_error,
298 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
299         .tuple_to_nlattr        = icmpv6_tuple_to_nlattr,
300         .nlattr_tuple_size      = icmpv6_nlattr_tuple_size,
301         .nlattr_to_tuple        = icmpv6_nlattr_to_tuple,
302         .nla_policy             = icmpv6_nla_policy,
303 #endif
304 #ifdef CONFIG_SYSCTL
305         .ctl_table_header       = &icmpv6_sysctl_header,
306         .ctl_table              = icmpv6_sysctl_table,
307 #endif
308 };