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9fb9cbb1 YK |
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 | * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> | |
12 | * - ICMPv6 tracking support. Derived from the original ip_conntrack code | |
13 | * net/ipv4/netfilter/ip_conntrack_proto_icmp.c which had the following | |
14 | * copyright information: | |
15 | * (C) 1999-2001 Paul `Rusty' Russell | |
16 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
17 | */ | |
18 | ||
19 | #include <linux/types.h> | |
20 | #include <linux/sched.h> | |
21 | #include <linux/timer.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/netfilter.h> | |
24 | #include <linux/in6.h> | |
25 | #include <linux/icmpv6.h> | |
26 | #include <linux/ipv6.h> | |
27 | #include <net/ipv6.h> | |
28 | #include <net/ip6_checksum.h> | |
29 | #include <linux/seq_file.h> | |
30 | #include <linux/netfilter_ipv6.h> | |
31 | #include <net/netfilter/nf_conntrack_tuple.h> | |
32 | #include <net/netfilter/nf_conntrack_protocol.h> | |
33 | #include <net/netfilter/nf_conntrack_core.h> | |
34 | #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h> | |
35 | ||
36 | unsigned long nf_ct_icmpv6_timeout = 30*HZ; | |
37 | ||
38 | #if 0 | |
39 | #define DEBUGP printk | |
40 | #else | |
41 | #define DEBUGP(format, args...) | |
42 | #endif | |
43 | ||
44 | static int icmpv6_pkt_to_tuple(const struct sk_buff *skb, | |
45 | unsigned int dataoff, | |
46 | struct nf_conntrack_tuple *tuple) | |
47 | { | |
48 | struct icmp6hdr _hdr, *hp; | |
49 | ||
50 | hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); | |
51 | if (hp == NULL) | |
52 | return 0; | |
53 | tuple->dst.u.icmp.type = hp->icmp6_type; | |
54 | tuple->src.u.icmp.id = hp->icmp6_identifier; | |
55 | tuple->dst.u.icmp.code = hp->icmp6_code; | |
56 | ||
57 | return 1; | |
58 | } | |
59 | ||
60 | static int icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple, | |
61 | const struct nf_conntrack_tuple *orig) | |
62 | { | |
63 | /* Add 1; spaces filled with 0. */ | |
64 | static u_int8_t invmap[] = { | |
65 | [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1, | |
66 | [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1, | |
67 | [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_QUERY + 1, | |
68 | [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_REPLY +1 | |
69 | }; | |
70 | ||
f16c9107 YK |
71 | int type = orig->dst.u.icmp.type - 128; |
72 | if (type < 0 || type >= sizeof(invmap) || !invmap[type]) | |
9fb9cbb1 YK |
73 | return 0; |
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 1; | |
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 | /* Print out the private part of the conntrack. */ | |
92 | static int icmpv6_print_conntrack(struct seq_file *s, | |
93 | const struct nf_conn *conntrack) | |
94 | { | |
95 | return 0; | |
96 | } | |
97 | ||
98 | /* Returns verdict for packet, or -1 for invalid. */ | |
99 | static int icmpv6_packet(struct nf_conn *ct, | |
100 | const struct sk_buff *skb, | |
101 | unsigned int dataoff, | |
102 | enum ip_conntrack_info ctinfo, | |
103 | int pf, | |
104 | unsigned int hooknum) | |
105 | { | |
106 | /* Try to delete connection immediately after all replies: | |
107 | won't actually vanish as we still have skb, and del_timer | |
108 | means this will only run once even if count hits zero twice | |
109 | (theoretically possible with SMP) */ | |
110 | if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY) { | |
111 | if (atomic_dec_and_test(&ct->proto.icmp.count) | |
112 | && del_timer(&ct->timeout)) | |
113 | ct->timeout.function((unsigned long)ct); | |
114 | } else { | |
115 | atomic_inc(&ct->proto.icmp.count); | |
116 | nf_conntrack_event_cache(IPCT_PROTOINFO_VOLATILE, skb); | |
117 | nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout); | |
118 | } | |
119 | ||
120 | return NF_ACCEPT; | |
121 | } | |
122 | ||
123 | /* Called when a new connection for this protocol found. */ | |
124 | static int icmpv6_new(struct nf_conn *conntrack, | |
125 | const struct sk_buff *skb, | |
126 | unsigned int dataoff) | |
127 | { | |
128 | static u_int8_t valid_new[] = { | |
129 | [ICMPV6_ECHO_REQUEST - 128] = 1, | |
130 | [ICMPV6_NI_QUERY - 128] = 1 | |
131 | }; | |
f16c9107 | 132 | int type = conntrack->tuplehash[0].tuple.dst.u.icmp.type - 128; |
9fb9cbb1 | 133 | |
f16c9107 | 134 | if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) { |
9fb9cbb1 | 135 | /* Can't create a new ICMPv6 `conn' with this. */ |
f16c9107 YK |
136 | DEBUGP("icmpv6: can't create new conn with type %u\n", |
137 | type + 128); | |
9fb9cbb1 YK |
138 | NF_CT_DUMP_TUPLE(&conntrack->tuplehash[0].tuple); |
139 | return 0; | |
140 | } | |
141 | atomic_set(&conntrack->proto.icmp.count, 0); | |
142 | return 1; | |
143 | } | |
144 | ||
145 | extern int | |
146 | nf_ct_ipv6_skip_exthdr(struct sk_buff *skb, int start, u8 *nexthdrp, int len); | |
147 | extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6; | |
148 | static int | |
149 | icmpv6_error_message(struct sk_buff *skb, | |
150 | unsigned int icmp6off, | |
151 | enum ip_conntrack_info *ctinfo, | |
152 | unsigned int hooknum) | |
153 | { | |
154 | struct nf_conntrack_tuple intuple, origtuple; | |
155 | struct nf_conntrack_tuple_hash *h; | |
156 | struct icmp6hdr _hdr, *hp; | |
157 | unsigned int inip6off; | |
158 | struct nf_conntrack_protocol *inproto; | |
159 | u_int8_t inprotonum; | |
160 | unsigned int inprotoff; | |
161 | ||
162 | NF_CT_ASSERT(skb->nfct == NULL); | |
163 | ||
164 | hp = skb_header_pointer(skb, icmp6off, sizeof(_hdr), &_hdr); | |
165 | if (hp == NULL) { | |
166 | DEBUGP("icmpv6_error: Can't get ICMPv6 hdr.\n"); | |
167 | return -NF_ACCEPT; | |
168 | } | |
169 | ||
170 | inip6off = icmp6off + sizeof(_hdr); | |
171 | if (skb_copy_bits(skb, inip6off+offsetof(struct ipv6hdr, nexthdr), | |
172 | &inprotonum, sizeof(inprotonum)) != 0) { | |
173 | DEBUGP("icmpv6_error: Can't get nexthdr in inner IPv6 header.\n"); | |
174 | return -NF_ACCEPT; | |
175 | } | |
176 | inprotoff = nf_ct_ipv6_skip_exthdr(skb, | |
177 | inip6off + sizeof(struct ipv6hdr), | |
178 | &inprotonum, | |
179 | skb->len - inip6off | |
180 | - sizeof(struct ipv6hdr)); | |
181 | ||
182 | if ((inprotoff < 0) || (inprotoff > skb->len) || | |
183 | (inprotonum == NEXTHDR_FRAGMENT)) { | |
184 | DEBUGP("icmpv6_error: Can't get protocol header in ICMPv6 payload.\n"); | |
185 | return -NF_ACCEPT; | |
186 | } | |
187 | ||
188 | inproto = nf_ct_find_proto(PF_INET6, inprotonum); | |
189 | ||
190 | /* Are they talking about one of our connections? */ | |
191 | if (!nf_ct_get_tuple(skb, inip6off, inprotoff, PF_INET6, inprotonum, | |
192 | &origtuple, &nf_conntrack_l3proto_ipv6, inproto)) { | |
193 | DEBUGP("icmpv6_error: Can't get tuple\n"); | |
194 | return -NF_ACCEPT; | |
195 | } | |
196 | ||
197 | /* Ordinarily, we'd expect the inverted tupleproto, but it's | |
198 | been preserved inside the ICMP. */ | |
199 | if (!nf_ct_invert_tuple(&intuple, &origtuple, | |
200 | &nf_conntrack_l3proto_ipv6, inproto)) { | |
201 | DEBUGP("icmpv6_error: Can't invert tuple\n"); | |
202 | return -NF_ACCEPT; | |
203 | } | |
204 | ||
205 | *ctinfo = IP_CT_RELATED; | |
206 | ||
207 | h = nf_conntrack_find_get(&intuple, NULL); | |
208 | if (!h) { | |
209 | DEBUGP("icmpv6_error: no match\n"); | |
210 | return -NF_ACCEPT; | |
211 | } else { | |
212 | if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) | |
213 | *ctinfo += IP_CT_IS_REPLY; | |
214 | } | |
215 | ||
216 | /* Update skb to refer to this connection */ | |
217 | skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general; | |
218 | skb->nfctinfo = *ctinfo; | |
219 | return -NF_ACCEPT; | |
220 | } | |
221 | ||
222 | static int | |
223 | icmpv6_error(struct sk_buff *skb, unsigned int dataoff, | |
224 | enum ip_conntrack_info *ctinfo, int pf, unsigned int hooknum) | |
225 | { | |
226 | struct icmp6hdr _ih, *icmp6h; | |
227 | ||
228 | icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih); | |
229 | if (icmp6h == NULL) { | |
230 | if (LOG_INVALID(IPPROTO_ICMPV6)) | |
231 | nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL, | |
232 | "nf_ct_icmpv6: short packet "); | |
233 | return -NF_ACCEPT; | |
234 | } | |
235 | ||
236 | if (hooknum != NF_IP6_PRE_ROUTING) | |
237 | goto skipped; | |
238 | ||
239 | /* Ignore it if the checksum's bogus. */ | |
240 | if (csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr, | |
241 | skb->len - dataoff, IPPROTO_ICMPV6, | |
242 | skb_checksum(skb, dataoff, | |
243 | skb->len - dataoff, 0))) { | |
244 | nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL, | |
245 | "nf_ct_icmpv6: ICMPv6 checksum failed\n"); | |
246 | return -NF_ACCEPT; | |
247 | } | |
248 | ||
249 | skipped: | |
250 | ||
251 | /* is not error message ? */ | |
252 | if (icmp6h->icmp6_type >= 128) | |
253 | return NF_ACCEPT; | |
254 | ||
255 | return icmpv6_error_message(skb, dataoff, ctinfo, hooknum); | |
256 | } | |
257 | ||
258 | struct nf_conntrack_protocol nf_conntrack_protocol_icmpv6 = | |
259 | { | |
260 | .l3proto = PF_INET6, | |
261 | .proto = IPPROTO_ICMPV6, | |
262 | .name = "icmpv6", | |
263 | .pkt_to_tuple = icmpv6_pkt_to_tuple, | |
264 | .invert_tuple = icmpv6_invert_tuple, | |
265 | .print_tuple = icmpv6_print_tuple, | |
266 | .print_conntrack = icmpv6_print_conntrack, | |
267 | .packet = icmpv6_packet, | |
268 | .new = icmpv6_new, | |
269 | .error = icmpv6_error, | |
270 | }; | |
271 | ||
272 | EXPORT_SYMBOL(nf_conntrack_protocol_icmpv6); |