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[NETFILTER]: nf_conntrack: move conntrack protocol sysctls to individual modules
[linux-2.6.22.y-op.git] / net / ipv4 / netfilter / nf_conntrack_l3proto_ipv4.c
blob786c4ce96cdfc306e21d7e3d65e1aef2edef27c8
1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
9 * - move L3 protocol dependent part to this file.
10 * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
11 * - add get_features() to support various size of conntrack
12 * structures.
13 *
14 * Derived from net/ipv4/netfilter/ip_conntrack_standalone.c
15 */
16
17 #include <linux/types.h>
18 #include <linux/ip.h>
19 #include <linux/netfilter.h>
20 #include <linux/module.h>
21 #include <linux/skbuff.h>
22 #include <linux/icmp.h>
23 #include <linux/sysctl.h>
24 #include <net/route.h>
25 #include <net/ip.h>
26
27 #include <linux/netfilter_ipv4.h>
28 #include <net/netfilter/nf_conntrack.h>
29 #include <net/netfilter/nf_conntrack_helper.h>
30 #include <net/netfilter/nf_conntrack_l4proto.h>
31 #include <net/netfilter/nf_conntrack_l3proto.h>
32 #include <net/netfilter/nf_conntrack_core.h>
33 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
34
35 #if 0
36 #define DEBUGP printk
37 #else
38 #define DEBUGP(format, args...)
39 #endif
40
41 static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
42 struct nf_conntrack_tuple *tuple)
43 {
44 u_int32_t _addrs[2], *ap;
45 ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
46 sizeof(u_int32_t) * 2, _addrs);
47 if (ap == NULL)
48 return 0;
49
50 tuple->src.u3.ip = ap[0];
51 tuple->dst.u3.ip = ap[1];
52
53 return 1;
54 }
55
56 static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
57 const struct nf_conntrack_tuple *orig)
58 {
59 tuple->src.u3.ip = orig->dst.u3.ip;
60 tuple->dst.u3.ip = orig->src.u3.ip;
61
62 return 1;
63 }
64
65 static int ipv4_print_tuple(struct seq_file *s,
66 const struct nf_conntrack_tuple *tuple)
67 {
68 return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
69 NIPQUAD(tuple->src.u3.ip),
70 NIPQUAD(tuple->dst.u3.ip));
71 }
72
73 static int ipv4_print_conntrack(struct seq_file *s,
74 const struct nf_conn *conntrack)
75 {
76 return 0;
77 }
78
79 /* Returns new sk_buff, or NULL */
80 static struct sk_buff *
81 nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
82 {
83 skb_orphan(skb);
84
85 local_bh_disable();
86 skb = ip_defrag(skb, user);
87 local_bh_enable();
88
89 if (skb)
90 ip_send_check(skb->nh.iph);
91
92 return skb;
93 }
94
95 static int
96 ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
97 u_int8_t *protonum)
98 {
99 /* Never happen */
100 if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET)) {
101 if (net_ratelimit()) {
102 printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n",
103 (*pskb)->nh.iph->protocol, hooknum);
104 }
105 return -NF_DROP;
106 }
107
108 *dataoff = (*pskb)->nh.raw - (*pskb)->data + (*pskb)->nh.iph->ihl*4;
109 *protonum = (*pskb)->nh.iph->protocol;
110
111 return NF_ACCEPT;
112 }
113
114 int nat_module_is_loaded = 0;
115 static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple)
116 {
117 if (nat_module_is_loaded)
118 return NF_CT_F_NAT;
119
120 return NF_CT_F_BASIC;
121 }
122
123 static unsigned int ipv4_confirm(unsigned int hooknum,
124 struct sk_buff **pskb,
125 const struct net_device *in,
126 const struct net_device *out,
127 int (*okfn)(struct sk_buff *))
128 {
129 /* We've seen it coming out the other side: confirm it */
130 return nf_conntrack_confirm(pskb);
131 }
132
133 static unsigned int ipv4_conntrack_help(unsigned int hooknum,
134 struct sk_buff **pskb,
135 const struct net_device *in,
136 const struct net_device *out,
137 int (*okfn)(struct sk_buff *))
138 {
139 struct nf_conn *ct;
140 enum ip_conntrack_info ctinfo;
141 struct nf_conn_help *help;
142
143 /* This is where we call the helper: as the packet goes out. */
144 ct = nf_ct_get(*pskb, &ctinfo);
145 if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
146 return NF_ACCEPT;
147
148 help = nfct_help(ct);
149 if (!help || !help->helper)
150 return NF_ACCEPT;
151
152 return help->helper->help(pskb,
153 (*pskb)->nh.raw - (*pskb)->data
154 + (*pskb)->nh.iph->ihl*4,
155 ct, ctinfo);
156 }
157
158 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
159 struct sk_buff **pskb,
160 const struct net_device *in,
161 const struct net_device *out,
162 int (*okfn)(struct sk_buff *))
163 {
164 #if !defined(CONFIG_IP_NF_NAT) && !defined(CONFIG_IP_NF_NAT_MODULE)
165 /* Previously seen (loopback)? Ignore. Do this before
166 fragment check. */
167 if ((*pskb)->nfct)
168 return NF_ACCEPT;
169 #endif
170
171 /* Gather fragments. */
172 if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
173 *pskb = nf_ct_ipv4_gather_frags(*pskb,
174 hooknum == NF_IP_PRE_ROUTING ?
175 IP_DEFRAG_CONNTRACK_IN :
176 IP_DEFRAG_CONNTRACK_OUT);
177 if (!*pskb)
178 return NF_STOLEN;
179 }
180 return NF_ACCEPT;
181 }
182
183 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
184 struct sk_buff **pskb,
185 const struct net_device *in,
186 const struct net_device *out,
187 int (*okfn)(struct sk_buff *))
188 {
189 return nf_conntrack_in(PF_INET, hooknum, pskb);
190 }
191
192 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
193 struct sk_buff **pskb,
194 const struct net_device *in,
195 const struct net_device *out,
196 int (*okfn)(struct sk_buff *))
197 {
198 /* root is playing with raw sockets. */
199 if ((*pskb)->len < sizeof(struct iphdr)
200 || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
201 if (net_ratelimit())
202 printk("ipt_hook: happy cracking.\n");
203 return NF_ACCEPT;
204 }
205 return nf_conntrack_in(PF_INET, hooknum, pskb);
206 }
207
208 /* Connection tracking may drop packets, but never alters them, so
209 make it the first hook. */
210 static struct nf_hook_ops ipv4_conntrack_ops[] = {
211 {
212 .hook = ipv4_conntrack_defrag,
213 .owner = THIS_MODULE,
214 .pf = PF_INET,
215 .hooknum = NF_IP_PRE_ROUTING,
216 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
217 },
218 {
219 .hook = ipv4_conntrack_in,
220 .owner = THIS_MODULE,
221 .pf = PF_INET,
222 .hooknum = NF_IP_PRE_ROUTING,
223 .priority = NF_IP_PRI_CONNTRACK,
224 },
225 {
226 .hook = ipv4_conntrack_defrag,
227 .owner = THIS_MODULE,
228 .pf = PF_INET,
229 .hooknum = NF_IP_LOCAL_OUT,
230 .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
231 },
232 {
233 .hook = ipv4_conntrack_local,
234 .owner = THIS_MODULE,
235 .pf = PF_INET,
236 .hooknum = NF_IP_LOCAL_OUT,
237 .priority = NF_IP_PRI_CONNTRACK,
238 },
239 {
240 .hook = ipv4_conntrack_help,
241 .owner = THIS_MODULE,
242 .pf = PF_INET,
243 .hooknum = NF_IP_POST_ROUTING,
244 .priority = NF_IP_PRI_CONNTRACK_HELPER,
245 },
246 {
247 .hook = ipv4_conntrack_help,
248 .owner = THIS_MODULE,
249 .pf = PF_INET,
250 .hooknum = NF_IP_LOCAL_IN,
251 .priority = NF_IP_PRI_CONNTRACK_HELPER,
252 },
253 {
254 .hook = ipv4_confirm,
255 .owner = THIS_MODULE,
256 .pf = PF_INET,
257 .hooknum = NF_IP_POST_ROUTING,
258 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
259 },
260 {
261 .hook = ipv4_confirm,
262 .owner = THIS_MODULE,
263 .pf = PF_INET,
264 .hooknum = NF_IP_LOCAL_IN,
265 .priority = NF_IP_PRI_CONNTRACK_CONFIRM,
266 },
267 };
268
269 /* Fast function for those who don't want to parse /proc (and I don't
270 blame them). */
271 /* Reversing the socket's dst/src point of view gives us the reply
272 mapping. */
273 static int
274 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
275 {
276 struct inet_sock *inet = inet_sk(sk);
277 struct nf_conntrack_tuple_hash *h;
278 struct nf_conntrack_tuple tuple;
279
280 NF_CT_TUPLE_U_BLANK(&tuple);
281 tuple.src.u3.ip = inet->rcv_saddr;
282 tuple.src.u.tcp.port = inet->sport;
283 tuple.dst.u3.ip = inet->daddr;
284 tuple.dst.u.tcp.port = inet->dport;
285 tuple.src.l3num = PF_INET;
286 tuple.dst.protonum = IPPROTO_TCP;
287
288 /* We only do TCP at the moment: is there a better way? */
289 if (strcmp(sk->sk_prot->name, "TCP")) {
290 DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
291 return -ENOPROTOOPT;
292 }
293
294 if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
295 DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
296 *len, sizeof(struct sockaddr_in));
297 return -EINVAL;
298 }
299
300 h = nf_conntrack_find_get(&tuple, NULL);
301 if (h) {
302 struct sockaddr_in sin;
303 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
304
305 sin.sin_family = AF_INET;
306 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
307 .tuple.dst.u.tcp.port;
308 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
309 .tuple.dst.u3.ip;
310 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
311
312 DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
313 NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
314 nf_ct_put(ct);
315 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
316 return -EFAULT;
317 else
318 return 0;
319 }
320 DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
321 NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
322 NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
323 return -ENOENT;
324 }
325
326 #if defined(CONFIG_NF_CT_NETLINK) || \
327 defined(CONFIG_NF_CT_NETLINK_MODULE)
328
329 #include <linux/netfilter/nfnetlink.h>
330 #include <linux/netfilter/nfnetlink_conntrack.h>
331
332 static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
333 const struct nf_conntrack_tuple *tuple)
334 {
335 NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
336 &tuple->src.u3.ip);
337 NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
338 &tuple->dst.u3.ip);
339 return 0;
340
341 nfattr_failure:
342 return -1;
343 }
344
345 static const size_t cta_min_ip[CTA_IP_MAX] = {
346 [CTA_IP_V4_SRC-1] = sizeof(u_int32_t),
347 [CTA_IP_V4_DST-1] = sizeof(u_int32_t),
348 };
349
350 static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
351 struct nf_conntrack_tuple *t)
352 {
353 if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
354 return -EINVAL;
355
356 if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
357 return -EINVAL;
358
359 t->src.u3.ip =
360 *(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
361 t->dst.u3.ip =
362 *(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_DST-1]);
363
364 return 0;
365 }
366 #endif
367
368 static struct nf_sockopt_ops so_getorigdst = {
369 .pf = PF_INET,
370 .get_optmin = SO_ORIGINAL_DST,
371 .get_optmax = SO_ORIGINAL_DST+1,
372 .get = &getorigdst,
373 };
374
375 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
376 .l3proto = PF_INET,
377 .name = "ipv4",
378 .pkt_to_tuple = ipv4_pkt_to_tuple,
379 .invert_tuple = ipv4_invert_tuple,
380 .print_tuple = ipv4_print_tuple,
381 .print_conntrack = ipv4_print_conntrack,
382 .prepare = ipv4_prepare,
383 .get_features = ipv4_get_features,
384 #if defined(CONFIG_NF_CT_NETLINK) || \
385 defined(CONFIG_NF_CT_NETLINK_MODULE)
386 .tuple_to_nfattr = ipv4_tuple_to_nfattr,
387 .nfattr_to_tuple = ipv4_nfattr_to_tuple,
388 #endif
389 .me = THIS_MODULE,
390 };
391
392 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
393 MODULE_LICENSE("GPL");
394
395 static int __init nf_conntrack_l3proto_ipv4_init(void)
396 {
397 int ret = 0;
398
399 need_conntrack();
400
401 ret = nf_register_sockopt(&so_getorigdst);
402 if (ret < 0) {
403 printk(KERN_ERR "Unable to register netfilter socket option\n");
404 return ret;
405 }
406
407 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
408 if (ret < 0) {
409 printk("nf_conntrack_ipv4: can't register tcp.\n");
410 goto cleanup_sockopt;
411 }
412
413 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
414 if (ret < 0) {
415 printk("nf_conntrack_ipv4: can't register udp.\n");
416 goto cleanup_tcp;
417 }
418
419 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
420 if (ret < 0) {
421 printk("nf_conntrack_ipv4: can't register icmp.\n");
422 goto cleanup_udp;
423 }
424
425 ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
426 if (ret < 0) {
427 printk("nf_conntrack_ipv4: can't register ipv4\n");
428 goto cleanup_icmp;
429 }
430
431 ret = nf_register_hooks(ipv4_conntrack_ops,
432 ARRAY_SIZE(ipv4_conntrack_ops));
433 if (ret < 0) {
434 printk("nf_conntrack_ipv4: can't register hooks.\n");
435 goto cleanup_ipv4;
436 }
437 return ret;
438
439 cleanup_ipv4:
440 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
441 cleanup_icmp:
442 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
443 cleanup_udp:
444 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
445 cleanup_tcp:
446 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
447 cleanup_sockopt:
448 nf_unregister_sockopt(&so_getorigdst);
449 return ret;
450 }
451
452 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
453 {
454 synchronize_net();
455 nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
456 nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
457 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
458 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
459 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
460 nf_unregister_sockopt(&so_getorigdst);
461 }
462
463 module_init(nf_conntrack_l3proto_ipv4_init);
464 module_exit(nf_conntrack_l3proto_ipv4_fini);
465
466 EXPORT_SYMBOL(nf_ct_ipv4_gather_frags);
linux v2.6.22.y-op