[NETFILTER]: nf_conntrack: remove 'ignore_conntrack' argument from nf_conntrack_find_get
[linux-2.6.git] / net / ipv4 / netfilter / nf_conntrack_l3proto_ipv4.c
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
9 #include <linux/types.h>
10 #include <linux/ip.h>
11 #include <linux/netfilter.h>
12 #include <linux/module.h>
13 #include <linux/skbuff.h>
14 #include <linux/icmp.h>
15 #include <linux/sysctl.h>
16 #include <net/route.h>
17 #include <net/ip.h>
18
19 #include <linux/netfilter_ipv4.h>
20 #include <net/netfilter/nf_conntrack.h>
21 #include <net/netfilter/nf_conntrack_helper.h>
22 #include <net/netfilter/nf_conntrack_l4proto.h>
23 #include <net/netfilter/nf_conntrack_l3proto.h>
24 #include <net/netfilter/nf_conntrack_core.h>
25 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
26
27 #if 0
28 #define DEBUGP printk
29 #else
30 #define DEBUGP(format, args...)
31 #endif
32
33 static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
34                              struct nf_conntrack_tuple *tuple)
35 {
36         __be32 _addrs[2], *ap;
37         ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
38                                 sizeof(u_int32_t) * 2, _addrs);
39         if (ap == NULL)
40                 return 0;
41
42         tuple->src.u3.ip = ap[0];
43         tuple->dst.u3.ip = ap[1];
44
45         return 1;
46 }
47
48 static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
49                            const struct nf_conntrack_tuple *orig)
50 {
51         tuple->src.u3.ip = orig->dst.u3.ip;
52         tuple->dst.u3.ip = orig->src.u3.ip;
53
54         return 1;
55 }
56
57 static int ipv4_print_tuple(struct seq_file *s,
58                             const struct nf_conntrack_tuple *tuple)
59 {
60         return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
61                           NIPQUAD(tuple->src.u3.ip),
62                           NIPQUAD(tuple->dst.u3.ip));
63 }
64
65 static int ipv4_print_conntrack(struct seq_file *s,
66                                 const struct nf_conn *conntrack)
67 {
68         return 0;
69 }
70
71 /* Returns new sk_buff, or NULL */
72 static struct sk_buff *
73 nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
74 {
75         skb_orphan(skb);
76
77         local_bh_disable();
78         skb = ip_defrag(skb, user);
79         local_bh_enable();
80
81         if (skb)
82                 ip_send_check(ip_hdr(skb));
83
84         return skb;
85 }
86
87 static int
88 ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
89              u_int8_t *protonum)
90 {
91         /* Never happen */
92         if (ip_hdr(*pskb)->frag_off & htons(IP_OFFSET)) {
93                 if (net_ratelimit()) {
94                         printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n",
95                         ip_hdr(*pskb)->protocol, hooknum);
96                 }
97                 return -NF_DROP;
98         }
99
100         *dataoff = skb_network_offset(*pskb) + ip_hdrlen(*pskb);
101         *protonum = ip_hdr(*pskb)->protocol;
102
103         return NF_ACCEPT;
104 }
105
106 static unsigned int ipv4_confirm(unsigned int hooknum,
107                                  struct sk_buff **pskb,
108                                  const struct net_device *in,
109                                  const struct net_device *out,
110                                  int (*okfn)(struct sk_buff *))
111 {
112         /* We've seen it coming out the other side: confirm it */
113         return nf_conntrack_confirm(pskb);
114 }
115
116 static unsigned int ipv4_conntrack_help(unsigned int hooknum,
117                                       struct sk_buff **pskb,
118                                       const struct net_device *in,
119                                       const struct net_device *out,
120                                       int (*okfn)(struct sk_buff *))
121 {
122         struct nf_conn *ct;
123         enum ip_conntrack_info ctinfo;
124         struct nf_conn_help *help;
125         struct nf_conntrack_helper *helper;
126
127         /* This is where we call the helper: as the packet goes out. */
128         ct = nf_ct_get(*pskb, &ctinfo);
129         if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
130                 return NF_ACCEPT;
131
132         help = nfct_help(ct);
133         if (!help)
134                 return NF_ACCEPT;
135         /* rcu_read_lock()ed by nf_hook_slow */
136         helper = rcu_dereference(help->helper);
137         if (!helper)
138                 return NF_ACCEPT;
139         return helper->help(pskb, skb_network_offset(*pskb) + ip_hdrlen(*pskb),
140                             ct, ctinfo);
141 }
142
143 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
144                                           struct sk_buff **pskb,
145                                           const struct net_device *in,
146                                           const struct net_device *out,
147                                           int (*okfn)(struct sk_buff *))
148 {
149         /* Previously seen (loopback)?  Ignore.  Do this before
150            fragment check. */
151         if ((*pskb)->nfct)
152                 return NF_ACCEPT;
153
154         /* Gather fragments. */
155         if (ip_hdr(*pskb)->frag_off & htons(IP_MF | IP_OFFSET)) {
156                 *pskb = nf_ct_ipv4_gather_frags(*pskb,
157                                                 hooknum == NF_IP_PRE_ROUTING ?
158                                                 IP_DEFRAG_CONNTRACK_IN :
159                                                 IP_DEFRAG_CONNTRACK_OUT);
160                 if (!*pskb)
161                         return NF_STOLEN;
162         }
163         return NF_ACCEPT;
164 }
165
166 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
167                                       struct sk_buff **pskb,
168                                       const struct net_device *in,
169                                       const struct net_device *out,
170                                       int (*okfn)(struct sk_buff *))
171 {
172         return nf_conntrack_in(PF_INET, hooknum, pskb);
173 }
174
175 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
176                                          struct sk_buff **pskb,
177                                          const struct net_device *in,
178                                          const struct net_device *out,
179                                          int (*okfn)(struct sk_buff *))
180 {
181         /* root is playing with raw sockets. */
182         if ((*pskb)->len < sizeof(struct iphdr)
183             || ip_hdrlen(*pskb) < sizeof(struct iphdr)) {
184                 if (net_ratelimit())
185                         printk("ipt_hook: happy cracking.\n");
186                 return NF_ACCEPT;
187         }
188         return nf_conntrack_in(PF_INET, hooknum, pskb);
189 }
190
191 /* Connection tracking may drop packets, but never alters them, so
192    make it the first hook. */
193 static struct nf_hook_ops ipv4_conntrack_ops[] = {
194         {
195                 .hook           = ipv4_conntrack_defrag,
196                 .owner          = THIS_MODULE,
197                 .pf             = PF_INET,
198                 .hooknum        = NF_IP_PRE_ROUTING,
199                 .priority       = NF_IP_PRI_CONNTRACK_DEFRAG,
200         },
201         {
202                 .hook           = ipv4_conntrack_in,
203                 .owner          = THIS_MODULE,
204                 .pf             = PF_INET,
205                 .hooknum        = NF_IP_PRE_ROUTING,
206                 .priority       = NF_IP_PRI_CONNTRACK,
207         },
208         {
209                 .hook           = ipv4_conntrack_defrag,
210                 .owner          = THIS_MODULE,
211                 .pf             = PF_INET,
212                 .hooknum        = NF_IP_LOCAL_OUT,
213                 .priority       = NF_IP_PRI_CONNTRACK_DEFRAG,
214         },
215         {
216                 .hook           = ipv4_conntrack_local,
217                 .owner          = THIS_MODULE,
218                 .pf             = PF_INET,
219                 .hooknum        = NF_IP_LOCAL_OUT,
220                 .priority       = NF_IP_PRI_CONNTRACK,
221         },
222         {
223                 .hook           = ipv4_conntrack_help,
224                 .owner          = THIS_MODULE,
225                 .pf             = PF_INET,
226                 .hooknum        = NF_IP_POST_ROUTING,
227                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
228         },
229         {
230                 .hook           = ipv4_conntrack_help,
231                 .owner          = THIS_MODULE,
232                 .pf             = PF_INET,
233                 .hooknum        = NF_IP_LOCAL_IN,
234                 .priority       = NF_IP_PRI_CONNTRACK_HELPER,
235         },
236         {
237                 .hook           = ipv4_confirm,
238                 .owner          = THIS_MODULE,
239                 .pf             = PF_INET,
240                 .hooknum        = NF_IP_POST_ROUTING,
241                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
242         },
243         {
244                 .hook           = ipv4_confirm,
245                 .owner          = THIS_MODULE,
246                 .pf             = PF_INET,
247                 .hooknum        = NF_IP_LOCAL_IN,
248                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
249         },
250 };
251
252 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
253 static int log_invalid_proto_min = 0;
254 static int log_invalid_proto_max = 255;
255
256 static ctl_table ip_ct_sysctl_table[] = {
257         {
258                 .ctl_name       = NET_IPV4_NF_CONNTRACK_MAX,
259                 .procname       = "ip_conntrack_max",
260                 .data           = &nf_conntrack_max,
261                 .maxlen         = sizeof(int),
262                 .mode           = 0644,
263                 .proc_handler   = &proc_dointvec,
264         },
265         {
266                 .ctl_name       = NET_IPV4_NF_CONNTRACK_COUNT,
267                 .procname       = "ip_conntrack_count",
268                 .data           = &nf_conntrack_count,
269                 .maxlen         = sizeof(int),
270                 .mode           = 0444,
271                 .proc_handler   = &proc_dointvec,
272         },
273         {
274                 .ctl_name       = NET_IPV4_NF_CONNTRACK_BUCKETS,
275                 .procname       = "ip_conntrack_buckets",
276                 .data           = &nf_conntrack_htable_size,
277                 .maxlen         = sizeof(unsigned int),
278                 .mode           = 0444,
279                 .proc_handler   = &proc_dointvec,
280         },
281         {
282                 .ctl_name       = NET_IPV4_NF_CONNTRACK_CHECKSUM,
283                 .procname       = "ip_conntrack_checksum",
284                 .data           = &nf_conntrack_checksum,
285                 .maxlen         = sizeof(int),
286                 .mode           = 0644,
287                 .proc_handler   = &proc_dointvec,
288         },
289         {
290                 .ctl_name       = NET_IPV4_NF_CONNTRACK_LOG_INVALID,
291                 .procname       = "ip_conntrack_log_invalid",
292                 .data           = &nf_ct_log_invalid,
293                 .maxlen         = sizeof(unsigned int),
294                 .mode           = 0644,
295                 .proc_handler   = &proc_dointvec_minmax,
296                 .strategy       = &sysctl_intvec,
297                 .extra1         = &log_invalid_proto_min,
298                 .extra2         = &log_invalid_proto_max,
299         },
300         {
301                 .ctl_name       = 0
302         }
303 };
304 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
305
306 /* Fast function for those who don't want to parse /proc (and I don't
307    blame them). */
308 /* Reversing the socket's dst/src point of view gives us the reply
309    mapping. */
310 static int
311 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
312 {
313         struct inet_sock *inet = inet_sk(sk);
314         struct nf_conntrack_tuple_hash *h;
315         struct nf_conntrack_tuple tuple;
316
317         NF_CT_TUPLE_U_BLANK(&tuple);
318         tuple.src.u3.ip = inet->rcv_saddr;
319         tuple.src.u.tcp.port = inet->sport;
320         tuple.dst.u3.ip = inet->daddr;
321         tuple.dst.u.tcp.port = inet->dport;
322         tuple.src.l3num = PF_INET;
323         tuple.dst.protonum = IPPROTO_TCP;
324
325         /* We only do TCP at the moment: is there a better way? */
326         if (strcmp(sk->sk_prot->name, "TCP")) {
327                 DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
328                 return -ENOPROTOOPT;
329         }
330
331         if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
332                 DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
333                        *len, sizeof(struct sockaddr_in));
334                 return -EINVAL;
335         }
336
337         h = nf_conntrack_find_get(&tuple);
338         if (h) {
339                 struct sockaddr_in sin;
340                 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
341
342                 sin.sin_family = AF_INET;
343                 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
344                         .tuple.dst.u.tcp.port;
345                 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
346                         .tuple.dst.u3.ip;
347                 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
348
349                 DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
350                        NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
351                 nf_ct_put(ct);
352                 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
353                         return -EFAULT;
354                 else
355                         return 0;
356         }
357         DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
358                NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
359                NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
360         return -ENOENT;
361 }
362
363 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
364
365 #include <linux/netfilter/nfnetlink.h>
366 #include <linux/netfilter/nfnetlink_conntrack.h>
367
368 static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
369                                 const struct nf_conntrack_tuple *tuple)
370 {
371         NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
372                 &tuple->src.u3.ip);
373         NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
374                 &tuple->dst.u3.ip);
375         return 0;
376
377 nfattr_failure:
378         return -1;
379 }
380
381 static const size_t cta_min_ip[CTA_IP_MAX] = {
382         [CTA_IP_V4_SRC-1]       = sizeof(u_int32_t),
383         [CTA_IP_V4_DST-1]       = sizeof(u_int32_t),
384 };
385
386 static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
387                                 struct nf_conntrack_tuple *t)
388 {
389         if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
390                 return -EINVAL;
391
392         if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
393                 return -EINVAL;
394
395         t->src.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
396         t->dst.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_DST-1]);
397
398         return 0;
399 }
400 #endif
401
402 static struct nf_sockopt_ops so_getorigdst = {
403         .pf             = PF_INET,
404         .get_optmin     = SO_ORIGINAL_DST,
405         .get_optmax     = SO_ORIGINAL_DST+1,
406         .get            = &getorigdst,
407 };
408
409 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
410         .l3proto         = PF_INET,
411         .name            = "ipv4",
412         .pkt_to_tuple    = ipv4_pkt_to_tuple,
413         .invert_tuple    = ipv4_invert_tuple,
414         .print_tuple     = ipv4_print_tuple,
415         .print_conntrack = ipv4_print_conntrack,
416         .prepare         = ipv4_prepare,
417 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
418         .tuple_to_nfattr = ipv4_tuple_to_nfattr,
419         .nfattr_to_tuple = ipv4_nfattr_to_tuple,
420 #endif
421 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
422         .ctl_table_path  = nf_net_ipv4_netfilter_sysctl_path,
423         .ctl_table       = ip_ct_sysctl_table,
424 #endif
425         .me              = THIS_MODULE,
426 };
427
428 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
429 MODULE_ALIAS("ip_conntrack");
430 MODULE_LICENSE("GPL");
431
432 static int __init nf_conntrack_l3proto_ipv4_init(void)
433 {
434         int ret = 0;
435
436         need_conntrack();
437
438         ret = nf_register_sockopt(&so_getorigdst);
439         if (ret < 0) {
440                 printk(KERN_ERR "Unable to register netfilter socket option\n");
441                 return ret;
442         }
443
444         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
445         if (ret < 0) {
446                 printk("nf_conntrack_ipv4: can't register tcp.\n");
447                 goto cleanup_sockopt;
448         }
449
450         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
451         if (ret < 0) {
452                 printk("nf_conntrack_ipv4: can't register udp.\n");
453                 goto cleanup_tcp;
454         }
455
456         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
457         if (ret < 0) {
458                 printk("nf_conntrack_ipv4: can't register icmp.\n");
459                 goto cleanup_udp;
460         }
461
462         ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
463         if (ret < 0) {
464                 printk("nf_conntrack_ipv4: can't register ipv4\n");
465                 goto cleanup_icmp;
466         }
467
468         ret = nf_register_hooks(ipv4_conntrack_ops,
469                                 ARRAY_SIZE(ipv4_conntrack_ops));
470         if (ret < 0) {
471                 printk("nf_conntrack_ipv4: can't register hooks.\n");
472                 goto cleanup_ipv4;
473         }
474 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
475         ret = nf_conntrack_ipv4_compat_init();
476         if (ret < 0)
477                 goto cleanup_hooks;
478 #endif
479         return ret;
480 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
481  cleanup_hooks:
482         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
483 #endif
484  cleanup_ipv4:
485         nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
486  cleanup_icmp:
487         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
488  cleanup_udp:
489         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
490  cleanup_tcp:
491         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
492  cleanup_sockopt:
493         nf_unregister_sockopt(&so_getorigdst);
494         return ret;
495 }
496
497 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
498 {
499         synchronize_net();
500 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
501         nf_conntrack_ipv4_compat_fini();
502 #endif
503         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
504         nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
505         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
506         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
507         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
508         nf_unregister_sockopt(&so_getorigdst);
509 }
510
511 module_init(nf_conntrack_l3proto_ipv4_init);
512 module_exit(nf_conntrack_l3proto_ipv4_fini);