netfilter: cleanup printk messages
[linux-2.6.git] / net / ipv4 / netfilter / nf_conntrack_l3proto_ipv4.c
1
2 /* (C) 1999-2001 Paul `Rusty' Russell
3  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9
10 #include <linux/types.h>
11 #include <linux/ip.h>
12 #include <linux/netfilter.h>
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/icmp.h>
16 #include <linux/sysctl.h>
17 #include <net/route.h>
18 #include <net/ip.h>
19
20 #include <linux/netfilter_ipv4.h>
21 #include <net/netfilter/nf_conntrack.h>
22 #include <net/netfilter/nf_conntrack_helper.h>
23 #include <net/netfilter/nf_conntrack_l4proto.h>
24 #include <net/netfilter/nf_conntrack_l3proto.h>
25 #include <net/netfilter/nf_conntrack_zones.h>
26 #include <net/netfilter/nf_conntrack_core.h>
27 #include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
28 #include <net/netfilter/nf_nat_helper.h>
29 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
30 #include <net/netfilter/nf_log.h>
31
32 int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb,
33                               struct nf_conn *ct,
34                               enum ip_conntrack_info ctinfo);
35 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook);
36
37 static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
38                               struct nf_conntrack_tuple *tuple)
39 {
40         const __be32 *ap;
41         __be32 _addrs[2];
42         ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
43                                 sizeof(u_int32_t) * 2, _addrs);
44         if (ap == NULL)
45                 return false;
46
47         tuple->src.u3.ip = ap[0];
48         tuple->dst.u3.ip = ap[1];
49
50         return true;
51 }
52
53 static bool ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
54                               const struct nf_conntrack_tuple *orig)
55 {
56         tuple->src.u3.ip = orig->dst.u3.ip;
57         tuple->dst.u3.ip = orig->src.u3.ip;
58
59         return true;
60 }
61
62 static int ipv4_print_tuple(struct seq_file *s,
63                             const struct nf_conntrack_tuple *tuple)
64 {
65         return seq_printf(s, "src=%pI4 dst=%pI4 ",
66                           &tuple->src.u3.ip, &tuple->dst.u3.ip);
67 }
68
69 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
70                             unsigned int *dataoff, u_int8_t *protonum)
71 {
72         const struct iphdr *iph;
73         struct iphdr _iph;
74
75         iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
76         if (iph == NULL)
77                 return -NF_DROP;
78
79         /* Conntrack defragments packets, we might still see fragments
80          * inside ICMP packets though. */
81         if (iph->frag_off & htons(IP_OFFSET))
82                 return -NF_DROP;
83
84         *dataoff = nhoff + (iph->ihl << 2);
85         *protonum = iph->protocol;
86
87         return NF_ACCEPT;
88 }
89
90 static unsigned int ipv4_confirm(unsigned int hooknum,
91                                  struct sk_buff *skb,
92                                  const struct net_device *in,
93                                  const struct net_device *out,
94                                  int (*okfn)(struct sk_buff *))
95 {
96         struct nf_conn *ct;
97         enum ip_conntrack_info ctinfo;
98         const struct nf_conn_help *help;
99         const struct nf_conntrack_helper *helper;
100         unsigned int ret;
101
102         /* This is where we call the helper: as the packet goes out. */
103         ct = nf_ct_get(skb, &ctinfo);
104         if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
105                 goto out;
106
107         help = nfct_help(ct);
108         if (!help)
109                 goto out;
110
111         /* rcu_read_lock()ed by nf_hook_slow */
112         helper = rcu_dereference(help->helper);
113         if (!helper)
114                 goto out;
115
116         ret = helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
117                            ct, ctinfo);
118         if (ret != NF_ACCEPT) {
119                 nf_log_packet(NFPROTO_IPV4, hooknum, skb, in, out, NULL,
120                               "nf_ct_%s: dropping packet", helper->name);
121                 return ret;
122         }
123
124         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status)) {
125                 typeof(nf_nat_seq_adjust_hook) seq_adjust;
126
127                 seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
128                 if (!seq_adjust || !seq_adjust(skb, ct, ctinfo)) {
129                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
130                         return NF_DROP;
131                 }
132         }
133 out:
134         /* We've seen it coming out the other side: confirm it */
135         return nf_conntrack_confirm(skb);
136 }
137
138 static unsigned int ipv4_conntrack_in(unsigned int hooknum,
139                                       struct sk_buff *skb,
140                                       const struct net_device *in,
141                                       const struct net_device *out,
142                                       int (*okfn)(struct sk_buff *))
143 {
144         return nf_conntrack_in(dev_net(in), PF_INET, hooknum, skb);
145 }
146
147 static unsigned int ipv4_conntrack_local(unsigned int hooknum,
148                                          struct sk_buff *skb,
149                                          const struct net_device *in,
150                                          const struct net_device *out,
151                                          int (*okfn)(struct sk_buff *))
152 {
153         /* root is playing with raw sockets. */
154         if (skb->len < sizeof(struct iphdr) ||
155             ip_hdrlen(skb) < sizeof(struct iphdr))
156                 return NF_ACCEPT;
157         return nf_conntrack_in(dev_net(out), PF_INET, hooknum, skb);
158 }
159
160 /* Connection tracking may drop packets, but never alters them, so
161    make it the first hook. */
162 static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
163         {
164                 .hook           = ipv4_conntrack_in,
165                 .owner          = THIS_MODULE,
166                 .pf             = NFPROTO_IPV4,
167                 .hooknum        = NF_INET_PRE_ROUTING,
168                 .priority       = NF_IP_PRI_CONNTRACK,
169         },
170         {
171                 .hook           = ipv4_conntrack_local,
172                 .owner          = THIS_MODULE,
173                 .pf             = NFPROTO_IPV4,
174                 .hooknum        = NF_INET_LOCAL_OUT,
175                 .priority       = NF_IP_PRI_CONNTRACK,
176         },
177         {
178                 .hook           = ipv4_confirm,
179                 .owner          = THIS_MODULE,
180                 .pf             = NFPROTO_IPV4,
181                 .hooknum        = NF_INET_POST_ROUTING,
182                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
183         },
184         {
185                 .hook           = ipv4_confirm,
186                 .owner          = THIS_MODULE,
187                 .pf             = NFPROTO_IPV4,
188                 .hooknum        = NF_INET_LOCAL_IN,
189                 .priority       = NF_IP_PRI_CONNTRACK_CONFIRM,
190         },
191 };
192
193 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
194 static int log_invalid_proto_min = 0;
195 static int log_invalid_proto_max = 255;
196
197 static ctl_table ip_ct_sysctl_table[] = {
198         {
199                 .procname       = "ip_conntrack_max",
200                 .data           = &nf_conntrack_max,
201                 .maxlen         = sizeof(int),
202                 .mode           = 0644,
203                 .proc_handler   = proc_dointvec,
204         },
205         {
206                 .procname       = "ip_conntrack_count",
207                 .data           = &init_net.ct.count,
208                 .maxlen         = sizeof(int),
209                 .mode           = 0444,
210                 .proc_handler   = proc_dointvec,
211         },
212         {
213                 .procname       = "ip_conntrack_buckets",
214                 .data           = &init_net.ct.htable_size,
215                 .maxlen         = sizeof(unsigned int),
216                 .mode           = 0444,
217                 .proc_handler   = proc_dointvec,
218         },
219         {
220                 .procname       = "ip_conntrack_checksum",
221                 .data           = &init_net.ct.sysctl_checksum,
222                 .maxlen         = sizeof(int),
223                 .mode           = 0644,
224                 .proc_handler   = proc_dointvec,
225         },
226         {
227                 .procname       = "ip_conntrack_log_invalid",
228                 .data           = &init_net.ct.sysctl_log_invalid,
229                 .maxlen         = sizeof(unsigned int),
230                 .mode           = 0644,
231                 .proc_handler   = proc_dointvec_minmax,
232                 .extra1         = &log_invalid_proto_min,
233                 .extra2         = &log_invalid_proto_max,
234         },
235         { }
236 };
237 #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
238
239 /* Fast function for those who don't want to parse /proc (and I don't
240    blame them). */
241 /* Reversing the socket's dst/src point of view gives us the reply
242    mapping. */
243 static int
244 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
245 {
246         const struct inet_sock *inet = inet_sk(sk);
247         const struct nf_conntrack_tuple_hash *h;
248         struct nf_conntrack_tuple tuple;
249
250         memset(&tuple, 0, sizeof(tuple));
251         tuple.src.u3.ip = inet->inet_rcv_saddr;
252         tuple.src.u.tcp.port = inet->inet_sport;
253         tuple.dst.u3.ip = inet->inet_daddr;
254         tuple.dst.u.tcp.port = inet->inet_dport;
255         tuple.src.l3num = PF_INET;
256         tuple.dst.protonum = sk->sk_protocol;
257
258         /* We only do TCP and SCTP at the moment: is there a better way? */
259         if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) {
260                 pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
261                 return -ENOPROTOOPT;
262         }
263
264         if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
265                 pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
266                          *len, sizeof(struct sockaddr_in));
267                 return -EINVAL;
268         }
269
270         h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple);
271         if (h) {
272                 struct sockaddr_in sin;
273                 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
274
275                 sin.sin_family = AF_INET;
276                 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
277                         .tuple.dst.u.tcp.port;
278                 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
279                         .tuple.dst.u3.ip;
280                 memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
281
282                 pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
283                          &sin.sin_addr.s_addr, ntohs(sin.sin_port));
284                 nf_ct_put(ct);
285                 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
286                         return -EFAULT;
287                 else
288                         return 0;
289         }
290         pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
291                  &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
292                  &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port));
293         return -ENOENT;
294 }
295
296 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
297
298 #include <linux/netfilter/nfnetlink.h>
299 #include <linux/netfilter/nfnetlink_conntrack.h>
300
301 static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
302                                 const struct nf_conntrack_tuple *tuple)
303 {
304         NLA_PUT_BE32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip);
305         NLA_PUT_BE32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip);
306         return 0;
307
308 nla_put_failure:
309         return -1;
310 }
311
312 static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
313         [CTA_IP_V4_SRC] = { .type = NLA_U32 },
314         [CTA_IP_V4_DST] = { .type = NLA_U32 },
315 };
316
317 static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
318                                 struct nf_conntrack_tuple *t)
319 {
320         if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
321                 return -EINVAL;
322
323         t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]);
324         t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]);
325
326         return 0;
327 }
328
329 static int ipv4_nlattr_tuple_size(void)
330 {
331         return nla_policy_len(ipv4_nla_policy, CTA_IP_MAX + 1);
332 }
333 #endif
334
335 static struct nf_sockopt_ops so_getorigdst = {
336         .pf             = PF_INET,
337         .get_optmin     = SO_ORIGINAL_DST,
338         .get_optmax     = SO_ORIGINAL_DST+1,
339         .get            = &getorigdst,
340         .owner          = THIS_MODULE,
341 };
342
343 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
344         .l3proto         = PF_INET,
345         .name            = "ipv4",
346         .pkt_to_tuple    = ipv4_pkt_to_tuple,
347         .invert_tuple    = ipv4_invert_tuple,
348         .print_tuple     = ipv4_print_tuple,
349         .get_l4proto     = ipv4_get_l4proto,
350 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
351         .tuple_to_nlattr = ipv4_tuple_to_nlattr,
352         .nlattr_tuple_size = ipv4_nlattr_tuple_size,
353         .nlattr_to_tuple = ipv4_nlattr_to_tuple,
354         .nla_policy      = ipv4_nla_policy,
355 #endif
356 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
357         .ctl_table_path  = nf_net_ipv4_netfilter_sysctl_path,
358         .ctl_table       = ip_ct_sysctl_table,
359 #endif
360         .me              = THIS_MODULE,
361 };
362
363 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
364                   &nf_conntrack_htable_size, 0600);
365
366 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
367 MODULE_ALIAS("ip_conntrack");
368 MODULE_LICENSE("GPL");
369
370 static int __init nf_conntrack_l3proto_ipv4_init(void)
371 {
372         int ret = 0;
373
374         need_conntrack();
375         nf_defrag_ipv4_enable();
376
377         ret = nf_register_sockopt(&so_getorigdst);
378         if (ret < 0) {
379                 printk(KERN_ERR "Unable to register netfilter socket option\n");
380                 return ret;
381         }
382
383         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4);
384         if (ret < 0) {
385                 pr_err("nf_conntrack_ipv4: can't register tcp.\n");
386                 goto cleanup_sockopt;
387         }
388
389         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4);
390         if (ret < 0) {
391                 pr_err("nf_conntrack_ipv4: can't register udp.\n");
392                 goto cleanup_tcp;
393         }
394
395         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp);
396         if (ret < 0) {
397                 pr_err("nf_conntrack_ipv4: can't register icmp.\n");
398                 goto cleanup_udp;
399         }
400
401         ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
402         if (ret < 0) {
403                 pr_err("nf_conntrack_ipv4: can't register ipv4\n");
404                 goto cleanup_icmp;
405         }
406
407         ret = nf_register_hooks(ipv4_conntrack_ops,
408                                 ARRAY_SIZE(ipv4_conntrack_ops));
409         if (ret < 0) {
410                 pr_err("nf_conntrack_ipv4: can't register hooks.\n");
411                 goto cleanup_ipv4;
412         }
413 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
414         ret = nf_conntrack_ipv4_compat_init();
415         if (ret < 0)
416                 goto cleanup_hooks;
417 #endif
418         return ret;
419 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
420  cleanup_hooks:
421         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
422 #endif
423  cleanup_ipv4:
424         nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
425  cleanup_icmp:
426         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
427  cleanup_udp:
428         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
429  cleanup_tcp:
430         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
431  cleanup_sockopt:
432         nf_unregister_sockopt(&so_getorigdst);
433         return ret;
434 }
435
436 static void __exit nf_conntrack_l3proto_ipv4_fini(void)
437 {
438         synchronize_net();
439 #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
440         nf_conntrack_ipv4_compat_fini();
441 #endif
442         nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
443         nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
444         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp);
445         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4);
446         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
447         nf_unregister_sockopt(&so_getorigdst);
448 }
449
450 module_init(nf_conntrack_l3proto_ipv4_init);
451 module_exit(nf_conntrack_l3proto_ipv4_fini);
452
453 void need_ipv4_conntrack(void)
454 {
455         return;
456 }
457 EXPORT_SYMBOL_GPL(need_ipv4_conntrack);