[NETFILTER]: {ip,ip6}_tables: reformat to eliminate differences
[linux-2.6] / net / ipv6 / netfilter / ip6_queue.c
1 /*
2  * This is a module which is used for queueing IPv6 packets and
3  * communicating with userspace via netlink.
4  *
5  * (C) 2001 Fernando Anton, this code is GPL.
6  *     IPv64 Project - Work based in IPv64 draft by Arturo Azcorra.
7  *     Universidad Carlos III de Madrid - Leganes (Madrid) - Spain
8  *     Universidad Politecnica de Alcala de Henares - Alcala de H. (Madrid) - Spain
9  *     email: fanton@it.uc3m.es
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  */
15 #include <linux/module.h>
16 #include <linux/skbuff.h>
17 #include <linux/init.h>
18 #include <linux/ipv6.h>
19 #include <linux/notifier.h>
20 #include <linux/netdevice.h>
21 #include <linux/netfilter.h>
22 #include <linux/netlink.h>
23 #include <linux/spinlock.h>
24 #include <linux/sysctl.h>
25 #include <linux/proc_fs.h>
26 #include <linux/seq_file.h>
27 #include <linux/mutex.h>
28 #include <net/net_namespace.h>
29 #include <net/sock.h>
30 #include <net/ipv6.h>
31 #include <net/ip6_route.h>
32 #include <net/netfilter/nf_queue.h>
33 #include <linux/netfilter_ipv4/ip_queue.h>
34 #include <linux/netfilter_ipv4/ip_tables.h>
35 #include <linux/netfilter_ipv6/ip6_tables.h>
36
37 #define IPQ_QMAX_DEFAULT 1024
38 #define IPQ_PROC_FS_NAME "ip6_queue"
39 #define NET_IPQ_QMAX 2088
40 #define NET_IPQ_QMAX_NAME "ip6_queue_maxlen"
41
42 typedef int (*ipq_cmpfn)(struct nf_queue_entry *, unsigned long);
43
44 static unsigned char copy_mode __read_mostly = IPQ_COPY_NONE;
45 static unsigned int queue_maxlen __read_mostly = IPQ_QMAX_DEFAULT;
46 static DEFINE_RWLOCK(queue_lock);
47 static int peer_pid __read_mostly;
48 static unsigned int copy_range __read_mostly;
49 static unsigned int queue_total;
50 static unsigned int queue_dropped = 0;
51 static unsigned int queue_user_dropped = 0;
52 static struct sock *ipqnl __read_mostly;
53 static LIST_HEAD(queue_list);
54 static DEFINE_MUTEX(ipqnl_mutex);
55
56 static inline void
57 __ipq_enqueue_entry(struct nf_queue_entry *entry)
58 {
59        list_add_tail(&entry->list, &queue_list);
60        queue_total++;
61 }
62
63 static inline int
64 __ipq_set_mode(unsigned char mode, unsigned int range)
65 {
66         int status = 0;
67
68         switch(mode) {
69         case IPQ_COPY_NONE:
70         case IPQ_COPY_META:
71                 copy_mode = mode;
72                 copy_range = 0;
73                 break;
74
75         case IPQ_COPY_PACKET:
76                 copy_mode = mode;
77                 copy_range = range;
78                 if (copy_range > 0xFFFF)
79                         copy_range = 0xFFFF;
80                 break;
81
82         default:
83                 status = -EINVAL;
84
85         }
86         return status;
87 }
88
89 static void __ipq_flush(ipq_cmpfn cmpfn, unsigned long data);
90
91 static inline void
92 __ipq_reset(void)
93 {
94         peer_pid = 0;
95         net_disable_timestamp();
96         __ipq_set_mode(IPQ_COPY_NONE, 0);
97         __ipq_flush(NULL, 0);
98 }
99
100 static struct nf_queue_entry *
101 ipq_find_dequeue_entry(unsigned long id)
102 {
103         struct nf_queue_entry *entry = NULL, *i;
104
105         write_lock_bh(&queue_lock);
106
107         list_for_each_entry(i, &queue_list, list) {
108                 if ((unsigned long)i == id) {
109                         entry = i;
110                         break;
111                 }
112         }
113
114         if (entry) {
115                 list_del(&entry->list);
116                 queue_total--;
117         }
118
119         write_unlock_bh(&queue_lock);
120         return entry;
121 }
122
123 static void
124 __ipq_flush(ipq_cmpfn cmpfn, unsigned long data)
125 {
126         struct nf_queue_entry *entry, *next;
127
128         list_for_each_entry_safe(entry, next, &queue_list, list) {
129                 if (!cmpfn || cmpfn(entry, data)) {
130                         list_del(&entry->list);
131                         queue_total--;
132                         nf_reinject(entry, NF_DROP);
133                 }
134         }
135 }
136
137 static void
138 ipq_flush(ipq_cmpfn cmpfn, unsigned long data)
139 {
140         write_lock_bh(&queue_lock);
141         __ipq_flush(cmpfn, data);
142         write_unlock_bh(&queue_lock);
143 }
144
145 static struct sk_buff *
146 ipq_build_packet_message(struct nf_queue_entry *entry, int *errp)
147 {
148         sk_buff_data_t old_tail;
149         size_t size = 0;
150         size_t data_len = 0;
151         struct sk_buff *skb;
152         struct ipq_packet_msg *pmsg;
153         struct nlmsghdr *nlh;
154         struct timeval tv;
155
156         read_lock_bh(&queue_lock);
157
158         switch (copy_mode) {
159         case IPQ_COPY_META:
160         case IPQ_COPY_NONE:
161                 size = NLMSG_SPACE(sizeof(*pmsg));
162                 data_len = 0;
163                 break;
164
165         case IPQ_COPY_PACKET:
166                 if ((entry->skb->ip_summed == CHECKSUM_PARTIAL ||
167                      entry->skb->ip_summed == CHECKSUM_COMPLETE) &&
168                     (*errp = skb_checksum_help(entry->skb))) {
169                         read_unlock_bh(&queue_lock);
170                         return NULL;
171                 }
172                 if (copy_range == 0 || copy_range > entry->skb->len)
173                         data_len = entry->skb->len;
174                 else
175                         data_len = copy_range;
176
177                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
178                 break;
179
180         default:
181                 *errp = -EINVAL;
182                 read_unlock_bh(&queue_lock);
183                 return NULL;
184         }
185
186         read_unlock_bh(&queue_lock);
187
188         skb = alloc_skb(size, GFP_ATOMIC);
189         if (!skb)
190                 goto nlmsg_failure;
191
192         old_tail = skb->tail;
193         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
194         pmsg = NLMSG_DATA(nlh);
195         memset(pmsg, 0, sizeof(*pmsg));
196
197         pmsg->packet_id       = (unsigned long )entry;
198         pmsg->data_len        = data_len;
199         tv = ktime_to_timeval(entry->skb->tstamp);
200         pmsg->timestamp_sec   = tv.tv_sec;
201         pmsg->timestamp_usec  = tv.tv_usec;
202         pmsg->mark            = entry->skb->mark;
203         pmsg->hook            = entry->hook;
204         pmsg->hw_protocol     = entry->skb->protocol;
205
206         if (entry->indev)
207                 strcpy(pmsg->indev_name, entry->indev->name);
208         else
209                 pmsg->indev_name[0] = '\0';
210
211         if (entry->outdev)
212                 strcpy(pmsg->outdev_name, entry->outdev->name);
213         else
214                 pmsg->outdev_name[0] = '\0';
215
216         if (entry->indev && entry->skb->dev) {
217                 pmsg->hw_type = entry->skb->dev->type;
218                 pmsg->hw_addrlen = dev_parse_header(entry->skb, pmsg->hw_addr);
219         }
220
221         if (data_len)
222                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
223                         BUG();
224
225         nlh->nlmsg_len = skb->tail - old_tail;
226         return skb;
227
228 nlmsg_failure:
229         if (skb)
230                 kfree_skb(skb);
231         *errp = -EINVAL;
232         printk(KERN_ERR "ip6_queue: error creating packet message\n");
233         return NULL;
234 }
235
236 static int
237 ipq_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
238 {
239         int status = -EINVAL;
240         struct sk_buff *nskb;
241
242         if (copy_mode == IPQ_COPY_NONE)
243                 return -EAGAIN;
244
245         nskb = ipq_build_packet_message(entry, &status);
246         if (nskb == NULL)
247                 return status;
248
249         write_lock_bh(&queue_lock);
250
251         if (!peer_pid)
252                 goto err_out_free_nskb;
253
254         if (queue_total >= queue_maxlen) {
255                 queue_dropped++;
256                 status = -ENOSPC;
257                 if (net_ratelimit())
258                         printk (KERN_WARNING "ip6_queue: fill at %d entries, "
259                                 "dropping packet(s).  Dropped: %d\n", queue_total,
260                                 queue_dropped);
261                 goto err_out_free_nskb;
262         }
263
264         /* netlink_unicast will either free the nskb or attach it to a socket */
265         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
266         if (status < 0) {
267                 queue_user_dropped++;
268                 goto err_out_unlock;
269         }
270
271         __ipq_enqueue_entry(entry);
272
273         write_unlock_bh(&queue_lock);
274         return status;
275
276 err_out_free_nskb:
277         kfree_skb(nskb);
278
279 err_out_unlock:
280         write_unlock_bh(&queue_lock);
281         return status;
282 }
283
284 static int
285 ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct nf_queue_entry *e)
286 {
287         int diff;
288         int err;
289         struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
290
291         if (v->data_len < sizeof(*user_iph))
292                 return 0;
293         diff = v->data_len - e->skb->len;
294         if (diff < 0) {
295                 if (pskb_trim(e->skb, v->data_len))
296                         return -ENOMEM;
297         } else if (diff > 0) {
298                 if (v->data_len > 0xFFFF)
299                         return -EINVAL;
300                 if (diff > skb_tailroom(e->skb)) {
301                         err = pskb_expand_head(e->skb, 0,
302                                                diff - skb_tailroom(e->skb),
303                                                GFP_ATOMIC);
304                         if (err) {
305                                 printk(KERN_WARNING "ip6_queue: OOM "
306                                       "in mangle, dropping packet\n");
307                                 return err;
308                         }
309                 }
310                 skb_put(e->skb, diff);
311         }
312         if (!skb_make_writable(e->skb, v->data_len))
313                 return -ENOMEM;
314         skb_copy_to_linear_data(e->skb, v->payload, v->data_len);
315         e->skb->ip_summed = CHECKSUM_NONE;
316
317         return 0;
318 }
319
320 static int
321 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
322 {
323         struct nf_queue_entry *entry;
324
325         if (vmsg->value > NF_MAX_VERDICT)
326                 return -EINVAL;
327
328         entry = ipq_find_dequeue_entry(vmsg->id);
329         if (entry == NULL)
330                 return -ENOENT;
331         else {
332                 int verdict = vmsg->value;
333
334                 if (vmsg->data_len && vmsg->data_len == len)
335                         if (ipq_mangle_ipv6(vmsg, entry) < 0)
336                                 verdict = NF_DROP;
337
338                 nf_reinject(entry, verdict);
339                 return 0;
340         }
341 }
342
343 static int
344 ipq_set_mode(unsigned char mode, unsigned int range)
345 {
346         int status;
347
348         write_lock_bh(&queue_lock);
349         status = __ipq_set_mode(mode, range);
350         write_unlock_bh(&queue_lock);
351         return status;
352 }
353
354 static int
355 ipq_receive_peer(struct ipq_peer_msg *pmsg,
356                  unsigned char type, unsigned int len)
357 {
358         int status = 0;
359
360         if (len < sizeof(*pmsg))
361                 return -EINVAL;
362
363         switch (type) {
364         case IPQM_MODE:
365                 status = ipq_set_mode(pmsg->msg.mode.value,
366                                       pmsg->msg.mode.range);
367                 break;
368
369         case IPQM_VERDICT:
370                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
371                         status = -EINVAL;
372                 else
373                         status = ipq_set_verdict(&pmsg->msg.verdict,
374                                                  len - sizeof(*pmsg));
375                         break;
376         default:
377                 status = -EINVAL;
378         }
379         return status;
380 }
381
382 static int
383 dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
384 {
385         if (entry->indev)
386                 if (entry->indev->ifindex == ifindex)
387                         return 1;
388
389         if (entry->outdev)
390                 if (entry->outdev->ifindex == ifindex)
391                         return 1;
392 #ifdef CONFIG_BRIDGE_NETFILTER
393         if (entry->skb->nf_bridge) {
394                 if (entry->skb->nf_bridge->physindev &&
395                     entry->skb->nf_bridge->physindev->ifindex == ifindex)
396                         return 1;
397                 if (entry->skb->nf_bridge->physoutdev &&
398                     entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
399                         return 1;
400         }
401 #endif
402         return 0;
403 }
404
405 static void
406 ipq_dev_drop(int ifindex)
407 {
408         ipq_flush(dev_cmp, ifindex);
409 }
410
411 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
412
413 static inline void
414 __ipq_rcv_skb(struct sk_buff *skb)
415 {
416         int status, type, pid, flags, nlmsglen, skblen;
417         struct nlmsghdr *nlh;
418
419         skblen = skb->len;
420         if (skblen < sizeof(*nlh))
421                 return;
422
423         nlh = nlmsg_hdr(skb);
424         nlmsglen = nlh->nlmsg_len;
425         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
426                 return;
427
428         pid = nlh->nlmsg_pid;
429         flags = nlh->nlmsg_flags;
430
431         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
432                 RCV_SKB_FAIL(-EINVAL);
433
434         if (flags & MSG_TRUNC)
435                 RCV_SKB_FAIL(-ECOMM);
436
437         type = nlh->nlmsg_type;
438         if (type < NLMSG_NOOP || type >= IPQM_MAX)
439                 RCV_SKB_FAIL(-EINVAL);
440
441         if (type <= IPQM_BASE)
442                 return;
443
444         if (security_netlink_recv(skb, CAP_NET_ADMIN))
445                 RCV_SKB_FAIL(-EPERM);
446
447         write_lock_bh(&queue_lock);
448
449         if (peer_pid) {
450                 if (peer_pid != pid) {
451                         write_unlock_bh(&queue_lock);
452                         RCV_SKB_FAIL(-EBUSY);
453                 }
454         } else {
455                 net_enable_timestamp();
456                 peer_pid = pid;
457         }
458
459         write_unlock_bh(&queue_lock);
460
461         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
462                                   nlmsglen - NLMSG_LENGTH(0));
463         if (status < 0)
464                 RCV_SKB_FAIL(status);
465
466         if (flags & NLM_F_ACK)
467                 netlink_ack(skb, nlh, 0);
468         return;
469 }
470
471 static void
472 ipq_rcv_skb(struct sk_buff *skb)
473 {
474         mutex_lock(&ipqnl_mutex);
475         __ipq_rcv_skb(skb);
476         mutex_unlock(&ipqnl_mutex);
477 }
478
479 static int
480 ipq_rcv_dev_event(struct notifier_block *this,
481                   unsigned long event, void *ptr)
482 {
483         struct net_device *dev = ptr;
484
485         if (dev->nd_net != &init_net)
486                 return NOTIFY_DONE;
487
488         /* Drop any packets associated with the downed device */
489         if (event == NETDEV_DOWN)
490                 ipq_dev_drop(dev->ifindex);
491         return NOTIFY_DONE;
492 }
493
494 static struct notifier_block ipq_dev_notifier = {
495         .notifier_call  = ipq_rcv_dev_event,
496 };
497
498 static int
499 ipq_rcv_nl_event(struct notifier_block *this,
500                  unsigned long event, void *ptr)
501 {
502         struct netlink_notify *n = ptr;
503
504         if (event == NETLINK_URELEASE &&
505             n->protocol == NETLINK_IP6_FW && n->pid) {
506                 write_lock_bh(&queue_lock);
507                 if ((n->net == &init_net) && (n->pid == peer_pid))
508                         __ipq_reset();
509                 write_unlock_bh(&queue_lock);
510         }
511         return NOTIFY_DONE;
512 }
513
514 static struct notifier_block ipq_nl_notifier = {
515         .notifier_call  = ipq_rcv_nl_event,
516 };
517
518 static struct ctl_table_header *ipq_sysctl_header;
519
520 static ctl_table ipq_table[] = {
521         {
522                 .ctl_name       = NET_IPQ_QMAX,
523                 .procname       = NET_IPQ_QMAX_NAME,
524                 .data           = &queue_maxlen,
525                 .maxlen         = sizeof(queue_maxlen),
526                 .mode           = 0644,
527                 .proc_handler   = proc_dointvec
528         },
529         { .ctl_name = 0 }
530 };
531
532 static ctl_table ipq_dir_table[] = {
533         {
534                 .ctl_name       = NET_IPV6,
535                 .procname       = "ipv6",
536                 .mode           = 0555,
537                 .child          = ipq_table
538         },
539         { .ctl_name = 0 }
540 };
541
542 static ctl_table ipq_root_table[] = {
543         {
544                 .ctl_name       = CTL_NET,
545                 .procname       = "net",
546                 .mode           = 0555,
547                 .child          = ipq_dir_table
548         },
549         { .ctl_name = 0 }
550 };
551
552 static int ip6_queue_show(struct seq_file *m, void *v)
553 {
554         read_lock_bh(&queue_lock);
555
556         seq_printf(m,
557                       "Peer PID          : %d\n"
558                       "Copy mode         : %hu\n"
559                       "Copy range        : %u\n"
560                       "Queue length      : %u\n"
561                       "Queue max. length : %u\n"
562                       "Queue dropped     : %u\n"
563                       "Netfilter dropped : %u\n",
564                       peer_pid,
565                       copy_mode,
566                       copy_range,
567                       queue_total,
568                       queue_maxlen,
569                       queue_dropped,
570                       queue_user_dropped);
571
572         read_unlock_bh(&queue_lock);
573         return 0;
574 }
575
576 static int ip6_queue_open(struct inode *inode, struct file *file)
577 {
578         return single_open(file, ip6_queue_show, NULL);
579 }
580
581 static const struct file_operations ip6_queue_proc_fops = {
582         .open           = ip6_queue_open,
583         .read           = seq_read,
584         .llseek         = seq_lseek,
585         .release        = single_release,
586         .owner          = THIS_MODULE,
587 };
588
589 static const struct nf_queue_handler nfqh = {
590         .name   = "ip6_queue",
591         .outfn  = &ipq_enqueue_packet,
592 };
593
594 static int __init ip6_queue_init(void)
595 {
596         int status = -ENOMEM;
597         struct proc_dir_entry *proc;
598
599         netlink_register_notifier(&ipq_nl_notifier);
600         ipqnl = netlink_kernel_create(&init_net, NETLINK_IP6_FW, 0,
601                                       ipq_rcv_skb, NULL, THIS_MODULE);
602         if (ipqnl == NULL) {
603                 printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
604                 goto cleanup_netlink_notifier;
605         }
606
607         proc = create_proc_entry(IPQ_PROC_FS_NAME, 0, init_net.proc_net);
608         if (proc) {
609                 proc->owner = THIS_MODULE;
610                 proc->proc_fops = &ip6_queue_proc_fops;
611         } else {
612                 printk(KERN_ERR "ip6_queue: failed to create proc entry\n");
613                 goto cleanup_ipqnl;
614         }
615
616         register_netdevice_notifier(&ipq_dev_notifier);
617         ipq_sysctl_header = register_sysctl_table(ipq_root_table);
618
619         status = nf_register_queue_handler(PF_INET6, &nfqh);
620         if (status < 0) {
621                 printk(KERN_ERR "ip6_queue: failed to register queue handler\n");
622                 goto cleanup_sysctl;
623         }
624         return status;
625
626 cleanup_sysctl:
627         unregister_sysctl_table(ipq_sysctl_header);
628         unregister_netdevice_notifier(&ipq_dev_notifier);
629         proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
630
631 cleanup_ipqnl:
632         sock_release(ipqnl->sk_socket);
633         mutex_lock(&ipqnl_mutex);
634         mutex_unlock(&ipqnl_mutex);
635
636 cleanup_netlink_notifier:
637         netlink_unregister_notifier(&ipq_nl_notifier);
638         return status;
639 }
640
641 static void __exit ip6_queue_fini(void)
642 {
643         nf_unregister_queue_handlers(&nfqh);
644         synchronize_net();
645         ipq_flush(NULL, 0);
646
647         unregister_sysctl_table(ipq_sysctl_header);
648         unregister_netdevice_notifier(&ipq_dev_notifier);
649         proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
650
651         sock_release(ipqnl->sk_socket);
652         mutex_lock(&ipqnl_mutex);
653         mutex_unlock(&ipqnl_mutex);
654
655         netlink_unregister_notifier(&ipq_nl_notifier);
656 }
657
658 MODULE_DESCRIPTION("IPv6 packet queue handler");
659 MODULE_LICENSE("GPL");
660
661 module_init(ip6_queue_init);
662 module_exit(ip6_queue_fini);