Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / net / ipv4 / netfilter / ip_queue.c
blobe59aabd0eae4f9a63559672914db90d5a54c97b6
1 /*
2 * This is a module which is used for queueing IPv4 packets and
3 * communicating with userspace via netlink.
5 * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
6 * (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/skbuff.h>
14 #include <linux/init.h>
15 #include <linux/ip.h>
16 #include <linux/notifier.h>
17 #include <linux/netdevice.h>
18 #include <linux/netfilter.h>
19 #include <linux/netfilter_ipv4/ip_queue.h>
20 #include <linux/netfilter_ipv4/ip_tables.h>
21 #include <linux/netlink.h>
22 #include <linux/spinlock.h>
23 #include <linux/sysctl.h>
24 #include <linux/proc_fs.h>
25 #include <linux/seq_file.h>
26 #include <linux/security.h>
27 #include <linux/net.h>
28 #include <linux/mutex.h>
29 #include <linux/slab.h>
30 #include <net/net_namespace.h>
31 #include <net/sock.h>
32 #include <net/route.h>
33 #include <net/netfilter/nf_queue.h>
34 #include <net/ip.h>
36 #define IPQ_QMAX_DEFAULT 1024
37 #define IPQ_PROC_FS_NAME "ip_queue"
38 #define NET_IPQ_QMAX 2088
39 #define NET_IPQ_QMAX_NAME "ip_queue_maxlen"
41 typedef int (*ipq_cmpfn)(struct nf_queue_entry *, unsigned long);
43 static unsigned char copy_mode __read_mostly = IPQ_COPY_NONE;
44 static unsigned int queue_maxlen __read_mostly = IPQ_QMAX_DEFAULT;
45 static DEFINE_SPINLOCK(queue_lock);
46 static int peer_pid __read_mostly;
47 static unsigned int copy_range __read_mostly;
48 static unsigned int queue_total;
49 static unsigned int queue_dropped = 0;
50 static unsigned int queue_user_dropped = 0;
51 static struct sock *ipqnl __read_mostly;
52 static LIST_HEAD(queue_list);
53 static DEFINE_MUTEX(ipqnl_mutex);
55 static inline void
56 __ipq_enqueue_entry(struct nf_queue_entry *entry)
58 list_add_tail(&entry->list, &queue_list);
59 queue_total++;
62 static inline int
63 __ipq_set_mode(unsigned char mode, unsigned int range)
65 int status = 0;
67 switch(mode) {
68 case IPQ_COPY_NONE:
69 case IPQ_COPY_META:
70 copy_mode = mode;
71 copy_range = 0;
72 break;
74 case IPQ_COPY_PACKET:
75 if (range > 0xFFFF)
76 range = 0xFFFF;
77 copy_range = range;
78 copy_mode = mode;
79 break;
81 default:
82 status = -EINVAL;
85 return status;
88 static void __ipq_flush(ipq_cmpfn cmpfn, unsigned long data);
90 static inline void
91 __ipq_reset(void)
93 peer_pid = 0;
94 net_disable_timestamp();
95 __ipq_set_mode(IPQ_COPY_NONE, 0);
96 __ipq_flush(NULL, 0);
99 static struct nf_queue_entry *
100 ipq_find_dequeue_entry(unsigned long id)
102 struct nf_queue_entry *entry = NULL, *i;
104 spin_lock_bh(&queue_lock);
106 list_for_each_entry(i, &queue_list, list) {
107 if ((unsigned long)i == id) {
108 entry = i;
109 break;
113 if (entry) {
114 list_del(&entry->list);
115 queue_total--;
118 spin_unlock_bh(&queue_lock);
119 return entry;
122 static void
123 __ipq_flush(ipq_cmpfn cmpfn, unsigned long data)
125 struct nf_queue_entry *entry, *next;
127 list_for_each_entry_safe(entry, next, &queue_list, list) {
128 if (!cmpfn || cmpfn(entry, data)) {
129 list_del(&entry->list);
130 queue_total--;
131 nf_reinject(entry, NF_DROP);
136 static void
137 ipq_flush(ipq_cmpfn cmpfn, unsigned long data)
139 spin_lock_bh(&queue_lock);
140 __ipq_flush(cmpfn, data);
141 spin_unlock_bh(&queue_lock);
144 static struct sk_buff *
145 ipq_build_packet_message(struct nf_queue_entry *entry, int *errp)
147 sk_buff_data_t old_tail;
148 size_t size = 0;
149 size_t data_len = 0;
150 struct sk_buff *skb;
151 struct ipq_packet_msg *pmsg;
152 struct nlmsghdr *nlh;
153 struct timeval tv;
155 switch (ACCESS_ONCE(copy_mode)) {
156 case IPQ_COPY_META:
157 case IPQ_COPY_NONE:
158 size = NLMSG_SPACE(sizeof(*pmsg));
159 break;
161 case IPQ_COPY_PACKET:
162 if (entry->skb->ip_summed == CHECKSUM_PARTIAL &&
163 (*errp = skb_checksum_help(entry->skb)))
164 return NULL;
166 data_len = ACCESS_ONCE(copy_range);
167 if (data_len == 0 || data_len > entry->skb->len)
168 data_len = entry->skb->len;
170 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
171 break;
173 default:
174 *errp = -EINVAL;
175 return NULL;
178 skb = alloc_skb(size, GFP_ATOMIC);
179 if (!skb)
180 goto nlmsg_failure;
182 old_tail = skb->tail;
183 nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
184 pmsg = NLMSG_DATA(nlh);
185 memset(pmsg, 0, sizeof(*pmsg));
187 pmsg->packet_id = (unsigned long )entry;
188 pmsg->data_len = data_len;
189 tv = ktime_to_timeval(entry->skb->tstamp);
190 pmsg->timestamp_sec = tv.tv_sec;
191 pmsg->timestamp_usec = tv.tv_usec;
192 pmsg->mark = entry->skb->mark;
193 pmsg->hook = entry->hook;
194 pmsg->hw_protocol = entry->skb->protocol;
196 if (entry->indev)
197 strcpy(pmsg->indev_name, entry->indev->name);
198 else
199 pmsg->indev_name[0] = '\0';
201 if (entry->outdev)
202 strcpy(pmsg->outdev_name, entry->outdev->name);
203 else
204 pmsg->outdev_name[0] = '\0';
206 if (entry->indev && entry->skb->dev &&
207 entry->skb->mac_header != entry->skb->network_header) {
208 pmsg->hw_type = entry->skb->dev->type;
209 pmsg->hw_addrlen = dev_parse_header(entry->skb,
210 pmsg->hw_addr);
213 if (data_len)
214 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
215 BUG();
217 nlh->nlmsg_len = skb->tail - old_tail;
218 return skb;
220 nlmsg_failure:
221 kfree_skb(skb);
222 *errp = -EINVAL;
223 printk(KERN_ERR "ip_queue: error creating packet message\n");
224 return NULL;
227 static int
228 ipq_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
230 int status = -EINVAL;
231 struct sk_buff *nskb;
233 if (copy_mode == IPQ_COPY_NONE)
234 return -EAGAIN;
236 nskb = ipq_build_packet_message(entry, &status);
237 if (nskb == NULL)
238 return status;
240 spin_lock_bh(&queue_lock);
242 if (!peer_pid)
243 goto err_out_free_nskb;
245 if (queue_total >= queue_maxlen) {
246 queue_dropped++;
247 status = -ENOSPC;
248 if (net_ratelimit())
249 printk (KERN_WARNING "ip_queue: full at %d entries, "
250 "dropping packets(s). Dropped: %d\n", queue_total,
251 queue_dropped);
252 goto err_out_free_nskb;
255 /* netlink_unicast will either free the nskb or attach it to a socket */
256 status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
257 if (status < 0) {
258 queue_user_dropped++;
259 goto err_out_unlock;
262 __ipq_enqueue_entry(entry);
264 spin_unlock_bh(&queue_lock);
265 return status;
267 err_out_free_nskb:
268 kfree_skb(nskb);
270 err_out_unlock:
271 spin_unlock_bh(&queue_lock);
272 return status;
275 static int
276 ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct nf_queue_entry *e)
278 int diff;
279 struct iphdr *user_iph = (struct iphdr *)v->payload;
280 struct sk_buff *nskb;
282 if (v->data_len < sizeof(*user_iph))
283 return 0;
284 diff = v->data_len - e->skb->len;
285 if (diff < 0) {
286 if (pskb_trim(e->skb, v->data_len))
287 return -ENOMEM;
288 } else if (diff > 0) {
289 if (v->data_len > 0xFFFF)
290 return -EINVAL;
291 if (diff > skb_tailroom(e->skb)) {
292 nskb = skb_copy_expand(e->skb, skb_headroom(e->skb),
293 diff, GFP_ATOMIC);
294 if (!nskb) {
295 printk(KERN_WARNING "ip_queue: error "
296 "in mangle, dropping packet\n");
297 return -ENOMEM;
299 kfree_skb(e->skb);
300 e->skb = nskb;
302 skb_put(e->skb, diff);
304 if (!skb_make_writable(e->skb, v->data_len))
305 return -ENOMEM;
306 skb_copy_to_linear_data(e->skb, v->payload, v->data_len);
307 e->skb->ip_summed = CHECKSUM_NONE;
309 return 0;
312 static int
313 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
315 struct nf_queue_entry *entry;
317 if (vmsg->value > NF_MAX_VERDICT || vmsg->value == NF_STOLEN)
318 return -EINVAL;
320 entry = ipq_find_dequeue_entry(vmsg->id);
321 if (entry == NULL)
322 return -ENOENT;
323 else {
324 int verdict = vmsg->value;
326 if (vmsg->data_len && vmsg->data_len == len)
327 if (ipq_mangle_ipv4(vmsg, entry) < 0)
328 verdict = NF_DROP;
330 nf_reinject(entry, verdict);
331 return 0;
335 static int
336 ipq_set_mode(unsigned char mode, unsigned int range)
338 int status;
340 spin_lock_bh(&queue_lock);
341 status = __ipq_set_mode(mode, range);
342 spin_unlock_bh(&queue_lock);
343 return status;
346 static int
347 ipq_receive_peer(struct ipq_peer_msg *pmsg,
348 unsigned char type, unsigned int len)
350 int status = 0;
352 if (len < sizeof(*pmsg))
353 return -EINVAL;
355 switch (type) {
356 case IPQM_MODE:
357 status = ipq_set_mode(pmsg->msg.mode.value,
358 pmsg->msg.mode.range);
359 break;
361 case IPQM_VERDICT:
362 status = ipq_set_verdict(&pmsg->msg.verdict,
363 len - sizeof(*pmsg));
364 break;
365 default:
366 status = -EINVAL;
368 return status;
371 static int
372 dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
374 if (entry->indev)
375 if (entry->indev->ifindex == ifindex)
376 return 1;
377 if (entry->outdev)
378 if (entry->outdev->ifindex == ifindex)
379 return 1;
380 #ifdef CONFIG_BRIDGE_NETFILTER
381 if (entry->skb->nf_bridge) {
382 if (entry->skb->nf_bridge->physindev &&
383 entry->skb->nf_bridge->physindev->ifindex == ifindex)
384 return 1;
385 if (entry->skb->nf_bridge->physoutdev &&
386 entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
387 return 1;
389 #endif
390 return 0;
393 static void
394 ipq_dev_drop(int ifindex)
396 ipq_flush(dev_cmp, ifindex);
399 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
401 static inline void
402 __ipq_rcv_skb(struct sk_buff *skb)
404 int status, type, pid, flags;
405 unsigned int nlmsglen, skblen;
406 struct nlmsghdr *nlh;
408 skblen = skb->len;
409 if (skblen < sizeof(*nlh))
410 return;
412 nlh = nlmsg_hdr(skb);
413 nlmsglen = nlh->nlmsg_len;
414 if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
415 return;
417 pid = nlh->nlmsg_pid;
418 flags = nlh->nlmsg_flags;
420 if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
421 RCV_SKB_FAIL(-EINVAL);
423 if (flags & MSG_TRUNC)
424 RCV_SKB_FAIL(-ECOMM);
426 type = nlh->nlmsg_type;
427 if (type < NLMSG_NOOP || type >= IPQM_MAX)
428 RCV_SKB_FAIL(-EINVAL);
430 if (type <= IPQM_BASE)
431 return;
433 if (security_netlink_recv(skb, CAP_NET_ADMIN))
434 RCV_SKB_FAIL(-EPERM);
436 spin_lock_bh(&queue_lock);
438 if (peer_pid) {
439 if (peer_pid != pid) {
440 spin_unlock_bh(&queue_lock);
441 RCV_SKB_FAIL(-EBUSY);
443 } else {
444 net_enable_timestamp();
445 peer_pid = pid;
448 spin_unlock_bh(&queue_lock);
450 status = ipq_receive_peer(NLMSG_DATA(nlh), type,
451 nlmsglen - NLMSG_LENGTH(0));
452 if (status < 0)
453 RCV_SKB_FAIL(status);
455 if (flags & NLM_F_ACK)
456 netlink_ack(skb, nlh, 0);
459 static void
460 ipq_rcv_skb(struct sk_buff *skb)
462 mutex_lock(&ipqnl_mutex);
463 __ipq_rcv_skb(skb);
464 mutex_unlock(&ipqnl_mutex);
467 static int
468 ipq_rcv_dev_event(struct notifier_block *this,
469 unsigned long event, void *ptr)
471 struct net_device *dev = ptr;
473 if (!net_eq(dev_net(dev), &init_net))
474 return NOTIFY_DONE;
476 /* Drop any packets associated with the downed device */
477 if (event == NETDEV_DOWN)
478 ipq_dev_drop(dev->ifindex);
479 return NOTIFY_DONE;
482 static struct notifier_block ipq_dev_notifier = {
483 .notifier_call = ipq_rcv_dev_event,
486 static int
487 ipq_rcv_nl_event(struct notifier_block *this,
488 unsigned long event, void *ptr)
490 struct netlink_notify *n = ptr;
492 if (event == NETLINK_URELEASE && n->protocol == NETLINK_FIREWALL) {
493 spin_lock_bh(&queue_lock);
494 if ((net_eq(n->net, &init_net)) && (n->pid == peer_pid))
495 __ipq_reset();
496 spin_unlock_bh(&queue_lock);
498 return NOTIFY_DONE;
501 static struct notifier_block ipq_nl_notifier = {
502 .notifier_call = ipq_rcv_nl_event,
505 #ifdef CONFIG_SYSCTL
506 static struct ctl_table_header *ipq_sysctl_header;
508 static ctl_table ipq_table[] = {
510 .procname = NET_IPQ_QMAX_NAME,
511 .data = &queue_maxlen,
512 .maxlen = sizeof(queue_maxlen),
513 .mode = 0644,
514 .proc_handler = proc_dointvec
518 #endif
520 #ifdef CONFIG_PROC_FS
521 static int ip_queue_show(struct seq_file *m, void *v)
523 spin_lock_bh(&queue_lock);
525 seq_printf(m,
526 "Peer PID : %d\n"
527 "Copy mode : %hu\n"
528 "Copy range : %u\n"
529 "Queue length : %u\n"
530 "Queue max. length : %u\n"
531 "Queue dropped : %u\n"
532 "Netlink dropped : %u\n",
533 peer_pid,
534 copy_mode,
535 copy_range,
536 queue_total,
537 queue_maxlen,
538 queue_dropped,
539 queue_user_dropped);
541 spin_unlock_bh(&queue_lock);
542 return 0;
545 static int ip_queue_open(struct inode *inode, struct file *file)
547 return single_open(file, ip_queue_show, NULL);
550 static const struct file_operations ip_queue_proc_fops = {
551 .open = ip_queue_open,
552 .read = seq_read,
553 .llseek = seq_lseek,
554 .release = single_release,
555 .owner = THIS_MODULE,
557 #endif
559 static const struct nf_queue_handler nfqh = {
560 .name = "ip_queue",
561 .outfn = &ipq_enqueue_packet,
564 static int __init ip_queue_init(void)
566 int status = -ENOMEM;
567 struct proc_dir_entry *proc __maybe_unused;
569 netlink_register_notifier(&ipq_nl_notifier);
570 ipqnl = netlink_kernel_create(&init_net, NETLINK_FIREWALL, 0,
571 ipq_rcv_skb, NULL, THIS_MODULE);
572 if (ipqnl == NULL) {
573 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
574 goto cleanup_netlink_notifier;
577 #ifdef CONFIG_PROC_FS
578 proc = proc_create(IPQ_PROC_FS_NAME, 0, init_net.proc_net,
579 &ip_queue_proc_fops);
580 if (!proc) {
581 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
582 goto cleanup_ipqnl;
584 #endif
585 register_netdevice_notifier(&ipq_dev_notifier);
586 #ifdef CONFIG_SYSCTL
587 ipq_sysctl_header = register_sysctl_paths(net_ipv4_ctl_path, ipq_table);
588 #endif
589 status = nf_register_queue_handler(NFPROTO_IPV4, &nfqh);
590 if (status < 0) {
591 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
592 goto cleanup_sysctl;
594 return status;
596 cleanup_sysctl:
597 #ifdef CONFIG_SYSCTL
598 unregister_sysctl_table(ipq_sysctl_header);
599 #endif
600 unregister_netdevice_notifier(&ipq_dev_notifier);
601 proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
602 cleanup_ipqnl: __maybe_unused
603 netlink_kernel_release(ipqnl);
604 mutex_lock(&ipqnl_mutex);
605 mutex_unlock(&ipqnl_mutex);
607 cleanup_netlink_notifier:
608 netlink_unregister_notifier(&ipq_nl_notifier);
609 return status;
612 static void __exit ip_queue_fini(void)
614 nf_unregister_queue_handlers(&nfqh);
616 ipq_flush(NULL, 0);
618 #ifdef CONFIG_SYSCTL
619 unregister_sysctl_table(ipq_sysctl_header);
620 #endif
621 unregister_netdevice_notifier(&ipq_dev_notifier);
622 proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
624 netlink_kernel_release(ipqnl);
625 mutex_lock(&ipqnl_mutex);
626 mutex_unlock(&ipqnl_mutex);
628 netlink_unregister_notifier(&ipq_nl_notifier);
631 MODULE_DESCRIPTION("IPv4 packet queue handler");
632 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
633 MODULE_LICENSE("GPL");
634 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_FIREWALL);
636 module_init(ip_queue_init);
637 module_exit(ip_queue_fini);