[NETFILTER]: nf_conntrack: make print_conntrack function optional for l4protos
[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 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         struct icmp6hdr _hdr, *hp;
36
37         hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
38         if (hp == NULL)
39                 return 0;
40         tuple->dst.u.icmp.type = hp->icmp6_type;
41         tuple->src.u.icmp.id = hp->icmp6_identifier;
42         tuple->dst.u.icmp.code = hp->icmp6_code;
43
44         return 1;
45 }
46
47 /* Add 1; spaces filled with 0. */
48 static u_int8_t invmap[] = {
49         [ICMPV6_ECHO_REQUEST - 128]     = ICMPV6_ECHO_REPLY + 1,
50         [ICMPV6_ECHO_REPLY - 128]       = ICMPV6_ECHO_REQUEST + 1,
51         [ICMPV6_NI_QUERY - 128]         = ICMPV6_NI_QUERY + 1,
52         [ICMPV6_NI_REPLY - 128]         = ICMPV6_NI_REPLY +1
53 };
54
55 static int icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
56                                const struct nf_conntrack_tuple *orig)
57 {
58         int type = orig->dst.u.icmp.type - 128;
59         if (type < 0 || type >= sizeof(invmap) || !invmap[type])
60                 return 0;
61
62         tuple->src.u.icmp.id   = orig->src.u.icmp.id;
63         tuple->dst.u.icmp.type = invmap[type] - 1;
64         tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
65         return 1;
66 }
67
68 /* Print out the per-protocol part of the tuple. */
69 static int icmpv6_print_tuple(struct seq_file *s,
70                               const struct nf_conntrack_tuple *tuple)
71 {
72         return seq_printf(s, "type=%u code=%u id=%u ",
73                           tuple->dst.u.icmp.type,
74                           tuple->dst.u.icmp.code,
75                           ntohs(tuple->src.u.icmp.id));
76 }
77
78 /* Returns verdict for packet, or -1 for invalid. */
79 static int icmpv6_packet(struct nf_conn *ct,
80                        const struct sk_buff *skb,
81                        unsigned int dataoff,
82                        enum ip_conntrack_info ctinfo,
83                        int pf,
84                        unsigned int hooknum)
85 {
86         /* Try to delete connection immediately after all replies:
87            won't actually vanish as we still have skb, and del_timer
88            means this will only run once even if count hits zero twice
89            (theoretically possible with SMP) */
90         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) {
91                 if (atomic_dec_and_test(&ct->proto.icmp.count)
92                     && del_timer(&ct->timeout))
93                         ct->timeout.function((unsigned long)ct);
94         } else {
95                 atomic_inc(&ct->proto.icmp.count);
96                 nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb);
97                 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout);
98         }
99
100         return NF_ACCEPT;
101 }
102
103 /* Called when a new connection for this protocol found. */
104 static int icmpv6_new(struct nf_conn *conntrack,
105                       const struct sk_buff *skb,
106                       unsigned int dataoff)
107 {
108         static u_int8_t valid_new[] = {
109                 [ICMPV6_ECHO_REQUEST - 128] = 1,
110                 [ICMPV6_NI_QUERY - 128] = 1
111         };
112         int type = conntrack->tuplehash[0].tuple.dst.u.icmp.type - 128;
113
114         if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
115                 /* Can't create a new ICMPv6 `conn' with this. */
116                 pr_debug("icmpv6: can't create new conn with type %u\n",
117                          type + 128);
118                 NF_CT_DUMP_TUPLE(&conntrack->tuplehash[0].tuple);
119                 return 0;
120         }
121         atomic_set(&conntrack->proto.icmp.count, 0);
122         return 1;
123 }
124
125 static int
126 icmpv6_error_message(struct sk_buff *skb,
127                      unsigned int icmp6off,
128                      enum ip_conntrack_info *ctinfo,
129                      unsigned int hooknum)
130 {
131         struct nf_conntrack_tuple intuple, origtuple;
132         struct nf_conntrack_tuple_hash *h;
133         struct nf_conntrack_l4proto *inproto;
134
135         NF_CT_ASSERT(skb->nfct == NULL);
136
137         /* Are they talking about one of our connections? */
138         if (!nf_ct_get_tuplepr(skb,
139                                skb_network_offset(skb)
140                                 + sizeof(struct ipv6hdr)
141                                 + sizeof(struct icmp6hdr),
142                                PF_INET6, &origtuple)) {
143                 pr_debug("icmpv6_error: Can't get tuple\n");
144                 return -NF_ACCEPT;
145         }
146
147         /* rcu_read_lock()ed by nf_hook_slow */
148         inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
149
150         /* Ordinarily, we'd expect the inverted tupleproto, but it's
151            been preserved inside the ICMP. */
152         if (!nf_ct_invert_tuple(&intuple, &origtuple,
153                                 &nf_conntrack_l3proto_ipv6, inproto)) {
154                 pr_debug("icmpv6_error: Can't invert tuple\n");
155                 return -NF_ACCEPT;
156         }
157
158         *ctinfo = IP_CT_RELATED;
159
160         h = nf_conntrack_find_get(&intuple);
161         if (!h) {
162                 pr_debug("icmpv6_error: no match\n");
163                 return -NF_ACCEPT;
164         } else {
165                 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
166                         *ctinfo += IP_CT_IS_REPLY;
167         }
168
169         /* Update skb to refer to this connection */
170         skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
171         skb->nfctinfo = *ctinfo;
172         return -NF_ACCEPT;
173 }
174
175 static int
176 icmpv6_error(struct sk_buff *skb, unsigned int dataoff,
177              enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum)
178 {
179         struct icmp6hdr _ih, *icmp6h;
180
181         icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
182         if (icmp6h == NULL) {
183                 if (LOG_INVALID(IPPROTO_ICMPV6))
184                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
185                               "nf_ct_icmpv6: short packet ");
186                 return -NF_ACCEPT;
187         }
188
189         if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
190             nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
191                 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL,
192                               "nf_ct_icmpv6: ICMPv6 checksum failed\n");
193                 return -NF_ACCEPT;
194         }
195
196         /* is not error message ? */
197         if (icmp6h->icmp6_type >= 128)
198                 return NF_ACCEPT;
199
200         return icmpv6_error_message(skb, dataoff, ctinfo, hooknum);
201 }
202
203 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
204
205 #include <linux/netfilter/nfnetlink.h>
206 #include <linux/netfilter/nfnetlink_conntrack.h>
207 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
208                                   const struct nf_conntrack_tuple *t)
209 {
210         NLA_PUT_BE16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id);
211         NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type);
212         NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code);
213
214         return 0;
215
216 nla_put_failure:
217         return -1;
218 }
219
220 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
221         [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
222         [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
223         [CTA_PROTO_ICMPV6_ID]   = { .type = NLA_U16 },
224 };
225
226 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
227                                 struct nf_conntrack_tuple *tuple)
228 {
229         if (!tb[CTA_PROTO_ICMPV6_TYPE]
230             || !tb[CTA_PROTO_ICMPV6_CODE]
231             || !tb[CTA_PROTO_ICMPV6_ID])
232                 return -EINVAL;
233
234         tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
235         tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
236         tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
237
238         if (tuple->dst.u.icmp.type < 128
239             || tuple->dst.u.icmp.type - 128 >= sizeof(invmap)
240             || !invmap[tuple->dst.u.icmp.type - 128])
241                 return -EINVAL;
242
243         return 0;
244 }
245 #endif
246
247 #ifdef CONFIG_SYSCTL
248 static struct ctl_table_header *icmpv6_sysctl_header;
249 static struct ctl_table icmpv6_sysctl_table[] = {
250         {
251                 .procname       = "nf_conntrack_icmpv6_timeout",
252                 .data           = &nf_ct_icmpv6_timeout,
253                 .maxlen         = sizeof(unsigned int),
254                 .mode           = 0644,
255                 .proc_handler   = &proc_dointvec_jiffies,
256         },
257         {
258                 .ctl_name       = 0
259         }
260 };
261 #endif /* CONFIG_SYSCTL */
262
263 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
264 {
265         .l3proto                = PF_INET6,
266         .l4proto                = IPPROTO_ICMPV6,
267         .name                   = "icmpv6",
268         .pkt_to_tuple           = icmpv6_pkt_to_tuple,
269         .invert_tuple           = icmpv6_invert_tuple,
270         .print_tuple            = icmpv6_print_tuple,
271         .packet                 = icmpv6_packet,
272         .new                    = icmpv6_new,
273         .error                  = icmpv6_error,
274 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
275         .tuple_to_nlattr        = icmpv6_tuple_to_nlattr,
276         .nlattr_to_tuple        = icmpv6_nlattr_to_tuple,
277         .nla_policy             = icmpv6_nla_policy,
278 #endif
279 #ifdef CONFIG_SYSCTL
280         .ctl_table_header       = &icmpv6_sysctl_header,
281         .ctl_table              = icmpv6_sysctl_table,
282 #endif
283 };