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 struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
289 struct sk_buff *nskb;
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 nskb = skb_copy_expand(e->skb, 0,
302 diff - skb_tailroom(e->skb),
303 GFP_ATOMIC);
304 if (!nskb) {
305 printk(KERN_WARNING "ip6_queue: OOM "
306 "in mangle, dropping packet\n");
307 return -ENOMEM;
308 }
309 kfree_skb(e->skb);
310 e->skb = nskb;
311 }
312 skb_put(e->skb, diff);
313 }
314 if (!skb_make_writable(e->skb, v->data_len))
315 return -ENOMEM;
316 skb_copy_to_linear_data(e->skb, v->payload, v->data_len);
317 e->skb->ip_summed = CHECKSUM_NONE;
318
319 return 0;
320 }
321
322 static int
323 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
324 {
325 struct nf_queue_entry *entry;
326
327 if (vmsg->value > NF_MAX_VERDICT)
328 return -EINVAL;
329
330 entry = ipq_find_dequeue_entry(vmsg->id);
331 if (entry == NULL)
332 return -ENOENT;
333 else {
334 int verdict = vmsg->value;
335
336 if (vmsg->data_len && vmsg->data_len == len)
337 if (ipq_mangle_ipv6(vmsg, entry) < 0)
338 verdict = NF_DROP;
339
340 nf_reinject(entry, verdict);
341 return 0;
342 }
343 }
344
345 static int
346 ipq_set_mode(unsigned char mode, unsigned int range)
347 {
348 int status;
349
350 write_lock_bh(&queue_lock);
351 status = __ipq_set_mode(mode, range);
352 write_unlock_bh(&queue_lock);
353 return status;
354 }
355
356 static int
357 ipq_receive_peer(struct ipq_peer_msg *pmsg,
358 unsigned char type, unsigned int len)
359 {
360 int status = 0;
361
362 if (len < sizeof(*pmsg))
363 return -EINVAL;
364
365 switch (type) {
366 case IPQM_MODE:
367 status = ipq_set_mode(pmsg->msg.mode.value,
368 pmsg->msg.mode.range);
369 break;
370
371 case IPQM_VERDICT:
372 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
373 status = -EINVAL;
374 else
375 status = ipq_set_verdict(&pmsg->msg.verdict,
376 len - sizeof(*pmsg));
377 break;
378 default:
379 status = -EINVAL;
380 }
381 return status;
382 }
383
384 static int
385 dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
386 {
387 if (entry->indev)
388 if (entry->indev->ifindex == ifindex)
389 return 1;
390
391 if (entry->outdev)
392 if (entry->outdev->ifindex == ifindex)
393 return 1;
394 #ifdef CONFIG_BRIDGE_NETFILTER
395 if (entry->skb->nf_bridge) {
396 if (entry->skb->nf_bridge->physindev &&
397 entry->skb->nf_bridge->physindev->ifindex == ifindex)
398 return 1;
399 if (entry->skb->nf_bridge->physoutdev &&
400 entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
401 return 1;
402 }
403 #endif
404 return 0;
405 }
406
407 static void
408 ipq_dev_drop(int ifindex)
409 {
410 ipq_flush(dev_cmp, ifindex);
411 }
412
413 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
414
415 static inline void
416 __ipq_rcv_skb(struct sk_buff *skb)
417 {
418 int status, type, pid, flags, nlmsglen, skblen;
419 struct nlmsghdr *nlh;
420
421 skblen = skb->len;
422 if (skblen < sizeof(*nlh))
423 return;
424
425 nlh = nlmsg_hdr(skb);
426 nlmsglen = nlh->nlmsg_len;
427 if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
428 return;
429
430 pid = nlh->nlmsg_pid;
431 flags = nlh->nlmsg_flags;
432
433 if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
434 RCV_SKB_FAIL(-EINVAL);
435
436 if (flags & MSG_TRUNC)
437 RCV_SKB_FAIL(-ECOMM);
438
439 type = nlh->nlmsg_type;
440 if (type < NLMSG_NOOP || type >= IPQM_MAX)
441 RCV_SKB_FAIL(-EINVAL);
442
443 if (type <= IPQM_BASE)
444 return;
445
446 if (security_netlink_recv(skb, CAP_NET_ADMIN))
447 RCV_SKB_FAIL(-EPERM);
448
449 write_lock_bh(&queue_lock);
450
451 if (peer_pid) {
452 if (peer_pid != pid) {
453 write_unlock_bh(&queue_lock);
454 RCV_SKB_FAIL(-EBUSY);
455 }
456 } else {
457 net_enable_timestamp();
458 peer_pid = pid;
459 }
460
461 write_unlock_bh(&queue_lock);
462
463 status = ipq_receive_peer(NLMSG_DATA(nlh), type,
464 nlmsglen - NLMSG_LENGTH(0));
465 if (status < 0)
466 RCV_SKB_FAIL(status);
467
468 if (flags & NLM_F_ACK)
469 netlink_ack(skb, nlh, 0);
470 return;
471 }
472
473 static void
474 ipq_rcv_skb(struct sk_buff *skb)
475 {
476 mutex_lock(&ipqnl_mutex);
477 __ipq_rcv_skb(skb);
478 mutex_unlock(&ipqnl_mutex);
479 }
480
481 static int
482 ipq_rcv_dev_event(struct notifier_block *this,
483 unsigned long event, void *ptr)
484 {
485 struct net_device *dev = ptr;
486
487 if (dev->nd_net != &init_net)
488 return NOTIFY_DONE;
489
490 /* Drop any packets associated with the downed device */
491 if (event == NETDEV_DOWN)
492 ipq_dev_drop(dev->ifindex);
493 return NOTIFY_DONE;
494 }
495
496 static struct notifier_block ipq_dev_notifier = {
497 .notifier_call = ipq_rcv_dev_event,
498 };
499
500 static int
501 ipq_rcv_nl_event(struct notifier_block *this,
502 unsigned long event, void *ptr)
503 {
504 struct netlink_notify *n = ptr;
505
506 if (event == NETLINK_URELEASE &&
507 n->protocol == NETLINK_IP6_FW && n->pid) {
508 write_lock_bh(&queue_lock);
509 if ((n->net == &init_net) && (n->pid == peer_pid))
510 __ipq_reset();
511 write_unlock_bh(&queue_lock);
512 }
513 return NOTIFY_DONE;
514 }
515
516 static struct notifier_block ipq_nl_notifier = {
517 .notifier_call = ipq_rcv_nl_event,
518 };
519
520 #ifdef CONFIG_SYSCTL
521 static struct ctl_table_header *ipq_sysctl_header;
522
523 static ctl_table ipq_table[] = {
524 {
525 .ctl_name = NET_IPQ_QMAX,
526 .procname = NET_IPQ_QMAX_NAME,
527 .data = &queue_maxlen,
528 .maxlen = sizeof(queue_maxlen),
529 .mode = 0644,
530 .proc_handler = proc_dointvec
531 },
532 { .ctl_name = 0 }
533 };
534 #endif
535
536 #ifdef CONFIG_PROC_FS
537 static int ip6_queue_show(struct seq_file *m, void *v)
538 {
539 read_lock_bh(&queue_lock);
540
541 seq_printf(m,
542 "Peer PID : %d\n"
543 "Copy mode : %hu\n"
544 "Copy range : %u\n"
545 "Queue length : %u\n"
546 "Queue max. length : %u\n"
547 "Queue dropped : %u\n"
548 "Netfilter dropped : %u\n",
549 peer_pid,
550 copy_mode,
551 copy_range,
552 queue_total,
553 queue_maxlen,
554 queue_dropped,
555 queue_user_dropped);
556
557 read_unlock_bh(&queue_lock);
558 return 0;
559 }
560
561 static int ip6_queue_open(struct inode *inode, struct file *file)
562 {
563 return single_open(file, ip6_queue_show, NULL);
564 }
565
566 static const struct file_operations ip6_queue_proc_fops = {
567 .open = ip6_queue_open,
568 .read = seq_read,
569 .llseek = seq_lseek,
570 .release = single_release,
571 .owner = THIS_MODULE,
572 };
573 #endif
574
575 static const struct nf_queue_handler nfqh = {
576 .name = "ip6_queue",
577 .outfn = &ipq_enqueue_packet,
578 };
579
580 static int __init ip6_queue_init(void)
581 {
582 int status = -ENOMEM;
583 struct proc_dir_entry *proc __maybe_unused;
584
585 netlink_register_notifier(&ipq_nl_notifier);
586 ipqnl = netlink_kernel_create(&init_net, NETLINK_IP6_FW, 0,
587 ipq_rcv_skb, NULL, THIS_MODULE);
588 if (ipqnl == NULL) {
589 printk(KERN_ERR "ip6_queue: failed to create netlink socket\n");
590 goto cleanup_netlink_notifier;
591 }
592
593 #ifdef CONFIG_PROC_FS
594 proc = proc_create(IPQ_PROC_FS_NAME, 0, init_net.proc_net,
595 &ip6_queue_proc_fops);
596 if (!proc) {
597 printk(KERN_ERR "ip6_queue: failed to create proc entry\n");
598 goto cleanup_ipqnl;
599 }
600 #endif
601 register_netdevice_notifier(&ipq_dev_notifier);
602 #ifdef CONFIG_SYSCTL
603 ipq_sysctl_header = register_sysctl_paths(net_ipv6_ctl_path, ipq_table);
604 #endif
605 status = nf_register_queue_handler(PF_INET6, &nfqh);
606 if (status < 0) {
607 printk(KERN_ERR "ip6_queue: failed to register queue handler\n");
608 goto cleanup_sysctl;
609 }
610 return status;
611
612 cleanup_sysctl:
613 #ifdef CONFIG_SYSCTL
614 unregister_sysctl_table(ipq_sysctl_header);
615 #endif
616 unregister_netdevice_notifier(&ipq_dev_notifier);
617 proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
618
619 cleanup_ipqnl: __maybe_unused
620 netlink_kernel_release(ipqnl);
621 mutex_lock(&ipqnl_mutex);
622 mutex_unlock(&ipqnl_mutex);
623
624 cleanup_netlink_notifier:
625 netlink_unregister_notifier(&ipq_nl_notifier);
626 return status;
627 }
628
629 static void __exit ip6_queue_fini(void)
630 {
631 nf_unregister_queue_handlers(&nfqh);
632 synchronize_net();
633 ipq_flush(NULL, 0);
634
635 #ifdef CONFIG_SYSCTL
636 unregister_sysctl_table(ipq_sysctl_header);
637 #endif
638 unregister_netdevice_notifier(&ipq_dev_notifier);
639 proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
640
641 netlink_kernel_release(ipqnl);
642 mutex_lock(&ipqnl_mutex);
643 mutex_unlock(&ipqnl_mutex);
644
645 netlink_unregister_notifier(&ipq_nl_notifier);
646 }
647
648 MODULE_DESCRIPTION("IPv6 packet queue handler");
649 MODULE_LICENSE("GPL");
650
651 module_init(ip6_queue_init);
652 module_exit(ip6_queue_fini);
653
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