ae975ac59c6a4da507b4399d3b4c53c71d2c53e5
[linux-2.6.git] / net / ipv4 / netfilter / ip_queue.c
1 /*
2  * This is a module which is used for queueing IPv4 packets and
3  * communicating with userspace via netlink.
4  *
5  * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
6  * (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
7  *
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.
11  *
12  * 2000-03-27: Simplified code (thanks to Andi Kleen for clues).
13  * 2000-05-20: Fixed notifier problems (following Miguel Freitas' report).
14  * 2000-06-19: Fixed so nfmark is copied to metadata (reported by Sebastian 
15  *             Zander).
16  * 2000-08-01: Added Nick Williams' MAC support.
17  * 2002-06-25: Code cleanup.
18  * 2005-01-10: Added /proc counter for dropped packets; fixed so
19  *             packets aren't delivered to user space if they're going 
20  *             to be dropped. 
21  * 2005-05-26: local_bh_{disable,enable} around nf_reinject (Harald Welte)
22  *
23  */
24 #include <linux/module.h>
25 #include <linux/skbuff.h>
26 #include <linux/init.h>
27 #include <linux/ip.h>
28 #include <linux/notifier.h>
29 #include <linux/netdevice.h>
30 #include <linux/netfilter.h>
31 #include <linux/netfilter_ipv4/ip_queue.h>
32 #include <linux/netfilter_ipv4/ip_tables.h>
33 #include <linux/netlink.h>
34 #include <linux/spinlock.h>
35 #include <linux/sysctl.h>
36 #include <linux/proc_fs.h>
37 #include <linux/security.h>
38 #include <net/sock.h>
39 #include <net/route.h>
40
41 #define IPQ_QMAX_DEFAULT 1024
42 #define IPQ_PROC_FS_NAME "ip_queue"
43 #define NET_IPQ_QMAX 2088
44 #define NET_IPQ_QMAX_NAME "ip_queue_maxlen"
45
46 struct ipq_rt_info {
47         __u8 tos;
48         __u32 daddr;
49         __u32 saddr;
50 };
51
52 struct ipq_queue_entry {
53         struct list_head list;
54         struct nf_info *info;
55         struct sk_buff *skb;
56         struct ipq_rt_info rt_info;
57 };
58
59 typedef int (*ipq_cmpfn)(struct ipq_queue_entry *, unsigned long);
60
61 static unsigned char copy_mode = IPQ_COPY_NONE;
62 static unsigned int queue_maxlen = IPQ_QMAX_DEFAULT;
63 static DEFINE_RWLOCK(queue_lock);
64 static int peer_pid;
65 static unsigned int copy_range;
66 static unsigned int queue_total;
67 static unsigned int queue_dropped = 0;
68 static unsigned int queue_user_dropped = 0;
69 static struct sock *ipqnl;
70 static LIST_HEAD(queue_list);
71 static DECLARE_MUTEX(ipqnl_sem);
72
73 static void
74 ipq_issue_verdict(struct ipq_queue_entry *entry, int verdict)
75 {
76         /* TCP input path (and probably other bits) assume to be called
77          * from softirq context, not from syscall, like ipq_issue_verdict is
78          * called.  TCP input path deadlocks with locks taken from timer
79          * softirq, e.g.  We therefore emulate this by local_bh_disable() */
80
81         local_bh_disable();
82         nf_reinject(entry->skb, entry->info, verdict);
83         local_bh_enable();
84
85         kfree(entry);
86 }
87
88 static inline void
89 __ipq_enqueue_entry(struct ipq_queue_entry *entry)
90 {
91        list_add(&entry->list, &queue_list);
92        queue_total++;
93 }
94
95 /*
96  * Find and return a queued entry matched by cmpfn, or return the last
97  * entry if cmpfn is NULL.
98  */
99 static inline struct ipq_queue_entry *
100 __ipq_find_entry(ipq_cmpfn cmpfn, unsigned long data)
101 {
102         struct list_head *p;
103
104         list_for_each_prev(p, &queue_list) {
105                 struct ipq_queue_entry *entry = (struct ipq_queue_entry *)p;
106                 
107                 if (!cmpfn || cmpfn(entry, data))
108                         return entry;
109         }
110         return NULL;
111 }
112
113 static inline void
114 __ipq_dequeue_entry(struct ipq_queue_entry *entry)
115 {
116         list_del(&entry->list);
117         queue_total--;
118 }
119
120 static inline struct ipq_queue_entry *
121 __ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
122 {
123         struct ipq_queue_entry *entry;
124
125         entry = __ipq_find_entry(cmpfn, data);
126         if (entry == NULL)
127                 return NULL;
128
129         __ipq_dequeue_entry(entry);
130         return entry;
131 }
132
133
134 static inline void
135 __ipq_flush(int verdict)
136 {
137         struct ipq_queue_entry *entry;
138         
139         while ((entry = __ipq_find_dequeue_entry(NULL, 0)))
140                 ipq_issue_verdict(entry, verdict);
141 }
142
143 static inline int
144 __ipq_set_mode(unsigned char mode, unsigned int range)
145 {
146         int status = 0;
147         
148         switch(mode) {
149         case IPQ_COPY_NONE:
150         case IPQ_COPY_META:
151                 copy_mode = mode;
152                 copy_range = 0;
153                 break;
154                 
155         case IPQ_COPY_PACKET:
156                 copy_mode = mode;
157                 copy_range = range;
158                 if (copy_range > 0xFFFF)
159                         copy_range = 0xFFFF;
160                 break;
161                 
162         default:
163                 status = -EINVAL;
164
165         }
166         return status;
167 }
168
169 static inline void
170 __ipq_reset(void)
171 {
172         peer_pid = 0;
173         net_disable_timestamp();
174         __ipq_set_mode(IPQ_COPY_NONE, 0);
175         __ipq_flush(NF_DROP);
176 }
177
178 static struct ipq_queue_entry *
179 ipq_find_dequeue_entry(ipq_cmpfn cmpfn, unsigned long data)
180 {
181         struct ipq_queue_entry *entry;
182         
183         write_lock_bh(&queue_lock);
184         entry = __ipq_find_dequeue_entry(cmpfn, data);
185         write_unlock_bh(&queue_lock);
186         return entry;
187 }
188
189 static void
190 ipq_flush(int verdict)
191 {
192         write_lock_bh(&queue_lock);
193         __ipq_flush(verdict);
194         write_unlock_bh(&queue_lock);
195 }
196
197 static struct sk_buff *
198 ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
199 {
200         unsigned char *old_tail;
201         size_t size = 0;
202         size_t data_len = 0;
203         struct sk_buff *skb;
204         struct ipq_packet_msg *pmsg;
205         struct nlmsghdr *nlh;
206
207         read_lock_bh(&queue_lock);
208         
209         switch (copy_mode) {
210         case IPQ_COPY_META:
211         case IPQ_COPY_NONE:
212                 size = NLMSG_SPACE(sizeof(*pmsg));
213                 data_len = 0;
214                 break;
215         
216         case IPQ_COPY_PACKET:
217                 if (entry->skb->ip_summed == CHECKSUM_HW &&
218                     (*errp = skb_checksum_help(entry->skb,
219                                                entry->info->outdev == NULL))) {
220                         read_unlock_bh(&queue_lock);
221                         return NULL;
222                 }
223                 if (copy_range == 0 || copy_range > entry->skb->len)
224                         data_len = entry->skb->len;
225                 else
226                         data_len = copy_range;
227                 
228                 size = NLMSG_SPACE(sizeof(*pmsg) + data_len);
229                 break;
230         
231         default:
232                 *errp = -EINVAL;
233                 read_unlock_bh(&queue_lock);
234                 return NULL;
235         }
236
237         read_unlock_bh(&queue_lock);
238
239         skb = alloc_skb(size, GFP_ATOMIC);
240         if (!skb)
241                 goto nlmsg_failure;
242                 
243         old_tail= skb->tail;
244         nlh = NLMSG_PUT(skb, 0, 0, IPQM_PACKET, size - sizeof(*nlh));
245         pmsg = NLMSG_DATA(nlh);
246         memset(pmsg, 0, sizeof(*pmsg));
247
248         pmsg->packet_id       = (unsigned long )entry;
249         pmsg->data_len        = data_len;
250         pmsg->timestamp_sec   = entry->skb->stamp.tv_sec;
251         pmsg->timestamp_usec  = entry->skb->stamp.tv_usec;
252         pmsg->mark            = entry->skb->nfmark;
253         pmsg->hook            = entry->info->hook;
254         pmsg->hw_protocol     = entry->skb->protocol;
255         
256         if (entry->info->indev)
257                 strcpy(pmsg->indev_name, entry->info->indev->name);
258         else
259                 pmsg->indev_name[0] = '\0';
260         
261         if (entry->info->outdev)
262                 strcpy(pmsg->outdev_name, entry->info->outdev->name);
263         else
264                 pmsg->outdev_name[0] = '\0';
265         
266         if (entry->info->indev && entry->skb->dev) {
267                 pmsg->hw_type = entry->skb->dev->type;
268                 if (entry->skb->dev->hard_header_parse)
269                         pmsg->hw_addrlen =
270                                 entry->skb->dev->hard_header_parse(entry->skb,
271                                                                    pmsg->hw_addr);
272         }
273         
274         if (data_len)
275                 if (skb_copy_bits(entry->skb, 0, pmsg->payload, data_len))
276                         BUG();
277                 
278         nlh->nlmsg_len = skb->tail - old_tail;
279         return skb;
280
281 nlmsg_failure:
282         if (skb)
283                 kfree_skb(skb);
284         *errp = -EINVAL;
285         printk(KERN_ERR "ip_queue: error creating packet message\n");
286         return NULL;
287 }
288
289 static int
290 ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data)
291 {
292         int status = -EINVAL;
293         struct sk_buff *nskb;
294         struct ipq_queue_entry *entry;
295
296         if (copy_mode == IPQ_COPY_NONE)
297                 return -EAGAIN;
298
299         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
300         if (entry == NULL) {
301                 printk(KERN_ERR "ip_queue: OOM in ipq_enqueue_packet()\n");
302                 return -ENOMEM;
303         }
304
305         entry->info = info;
306         entry->skb = skb;
307
308         if (entry->info->hook == NF_IP_LOCAL_OUT) {
309                 struct iphdr *iph = skb->nh.iph;
310
311                 entry->rt_info.tos = iph->tos;
312                 entry->rt_info.daddr = iph->daddr;
313                 entry->rt_info.saddr = iph->saddr;
314         }
315
316         nskb = ipq_build_packet_message(entry, &status);
317         if (nskb == NULL)
318                 goto err_out_free;
319                 
320         write_lock_bh(&queue_lock);
321         
322         if (!peer_pid)
323                 goto err_out_free_nskb; 
324
325         if (queue_total >= queue_maxlen) {
326                 queue_dropped++;
327                 status = -ENOSPC;
328                 if (net_ratelimit())
329                           printk (KERN_WARNING "ip_queue: full at %d entries, "
330                                   "dropping packets(s). Dropped: %d\n", queue_total,
331                                   queue_dropped);
332                 goto err_out_free_nskb;
333         }
334
335         /* netlink_unicast will either free the nskb or attach it to a socket */ 
336         status = netlink_unicast(ipqnl, nskb, peer_pid, MSG_DONTWAIT);
337         if (status < 0) {
338                 queue_user_dropped++;
339                 goto err_out_unlock;
340         }
341
342         __ipq_enqueue_entry(entry);
343
344         write_unlock_bh(&queue_lock);
345         return status;
346
347 err_out_free_nskb:
348         kfree_skb(nskb); 
349         
350 err_out_unlock:
351         write_unlock_bh(&queue_lock);
352
353 err_out_free:
354         kfree(entry);
355         return status;
356 }
357
358 static int
359 ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
360 {
361         int diff;
362         struct iphdr *user_iph = (struct iphdr *)v->payload;
363
364         if (v->data_len < sizeof(*user_iph))
365                 return 0;
366         diff = v->data_len - e->skb->len;
367         if (diff < 0)
368                 skb_trim(e->skb, v->data_len);
369         else if (diff > 0) {
370                 if (v->data_len > 0xFFFF)
371                         return -EINVAL;
372                 if (diff > skb_tailroom(e->skb)) {
373                         struct sk_buff *newskb;
374                         
375                         newskb = skb_copy_expand(e->skb,
376                                                  skb_headroom(e->skb),
377                                                  diff,
378                                                  GFP_ATOMIC);
379                         if (newskb == NULL) {
380                                 printk(KERN_WARNING "ip_queue: OOM "
381                                       "in mangle, dropping packet\n");
382                                 return -ENOMEM;
383                         }
384                         if (e->skb->sk)
385                                 skb_set_owner_w(newskb, e->skb->sk);
386                         kfree_skb(e->skb);
387                         e->skb = newskb;
388                 }
389                 skb_put(e->skb, diff);
390         }
391         if (!skb_make_writable(&e->skb, v->data_len))
392                 return -ENOMEM;
393         memcpy(e->skb->data, v->payload, v->data_len);
394         e->skb->ip_summed = CHECKSUM_NONE;
395
396         /*
397          * Extra routing may needed on local out, as the QUEUE target never
398          * returns control to the table.
399          */
400         if (e->info->hook == NF_IP_LOCAL_OUT) {
401                 struct iphdr *iph = e->skb->nh.iph;
402
403                 if (!(iph->tos == e->rt_info.tos
404                       && iph->daddr == e->rt_info.daddr
405                       && iph->saddr == e->rt_info.saddr))
406                         return ip_route_me_harder(&e->skb);
407         }
408         return 0;
409 }
410
411 static inline int
412 id_cmp(struct ipq_queue_entry *e, unsigned long id)
413 {
414         return (id == (unsigned long )e);
415 }
416
417 static int
418 ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len)
419 {
420         struct ipq_queue_entry *entry;
421
422         if (vmsg->value > NF_MAX_VERDICT)
423                 return -EINVAL;
424
425         entry = ipq_find_dequeue_entry(id_cmp, vmsg->id);
426         if (entry == NULL)
427                 return -ENOENT;
428         else {
429                 int verdict = vmsg->value;
430                 
431                 if (vmsg->data_len && vmsg->data_len == len)
432                         if (ipq_mangle_ipv4(vmsg, entry) < 0)
433                                 verdict = NF_DROP;
434                 
435                 ipq_issue_verdict(entry, verdict);
436                 return 0;
437         }
438 }
439
440 static int
441 ipq_set_mode(unsigned char mode, unsigned int range)
442 {
443         int status;
444
445         write_lock_bh(&queue_lock);
446         status = __ipq_set_mode(mode, range);
447         write_unlock_bh(&queue_lock);
448         return status;
449 }
450
451 static int
452 ipq_receive_peer(struct ipq_peer_msg *pmsg,
453                  unsigned char type, unsigned int len)
454 {
455         int status = 0;
456
457         if (len < sizeof(*pmsg))
458                 return -EINVAL;
459
460         switch (type) {
461         case IPQM_MODE:
462                 status = ipq_set_mode(pmsg->msg.mode.value,
463                                       pmsg->msg.mode.range);
464                 break;
465                 
466         case IPQM_VERDICT:
467                 if (pmsg->msg.verdict.value > NF_MAX_VERDICT)
468                         status = -EINVAL;
469                 else
470                         status = ipq_set_verdict(&pmsg->msg.verdict,
471                                                  len - sizeof(*pmsg));
472                         break;
473         default:
474                 status = -EINVAL;
475         }
476         return status;
477 }
478
479 static int
480 dev_cmp(struct ipq_queue_entry *entry, unsigned long ifindex)
481 {
482         if (entry->info->indev)
483                 if (entry->info->indev->ifindex == ifindex)
484                         return 1;
485                         
486         if (entry->info->outdev)
487                 if (entry->info->outdev->ifindex == ifindex)
488                         return 1;
489
490         return 0;
491 }
492
493 static void
494 ipq_dev_drop(int ifindex)
495 {
496         struct ipq_queue_entry *entry;
497         
498         while ((entry = ipq_find_dequeue_entry(dev_cmp, ifindex)) != NULL)
499                 ipq_issue_verdict(entry, NF_DROP);
500 }
501
502 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
503
504 static inline void
505 ipq_rcv_skb(struct sk_buff *skb)
506 {
507         int status, type, pid, flags, nlmsglen, skblen;
508         struct nlmsghdr *nlh;
509
510         skblen = skb->len;
511         if (skblen < sizeof(*nlh))
512                 return;
513
514         nlh = (struct nlmsghdr *)skb->data;
515         nlmsglen = nlh->nlmsg_len;
516         if (nlmsglen < sizeof(*nlh) || skblen < nlmsglen)
517                 return;
518
519         pid = nlh->nlmsg_pid;
520         flags = nlh->nlmsg_flags;
521         
522         if(pid <= 0 || !(flags & NLM_F_REQUEST) || flags & NLM_F_MULTI)
523                 RCV_SKB_FAIL(-EINVAL);
524                 
525         if (flags & MSG_TRUNC)
526                 RCV_SKB_FAIL(-ECOMM);
527                 
528         type = nlh->nlmsg_type;
529         if (type < NLMSG_NOOP || type >= IPQM_MAX)
530                 RCV_SKB_FAIL(-EINVAL);
531                 
532         if (type <= IPQM_BASE)
533                 return;
534                 
535         if (security_netlink_recv(skb))
536                 RCV_SKB_FAIL(-EPERM);
537         
538         write_lock_bh(&queue_lock);
539         
540         if (peer_pid) {
541                 if (peer_pid != pid) {
542                         write_unlock_bh(&queue_lock);
543                         RCV_SKB_FAIL(-EBUSY);
544                 }
545         } else {
546                 net_enable_timestamp();
547                 peer_pid = pid;
548         }
549                 
550         write_unlock_bh(&queue_lock);
551         
552         status = ipq_receive_peer(NLMSG_DATA(nlh), type,
553                                   skblen - NLMSG_LENGTH(0));
554         if (status < 0)
555                 RCV_SKB_FAIL(status);
556                 
557         if (flags & NLM_F_ACK)
558                 netlink_ack(skb, nlh, 0);
559         return;
560 }
561
562 static void
563 ipq_rcv_sk(struct sock *sk, int len)
564 {
565         struct sk_buff *skb;
566         unsigned int qlen;
567
568         down(&ipqnl_sem);
569                         
570         for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
571                 skb = skb_dequeue(&sk->sk_receive_queue);
572                 ipq_rcv_skb(skb);
573                 kfree_skb(skb);
574         }
575                 
576         up(&ipqnl_sem);
577 }
578
579 static int
580 ipq_rcv_dev_event(struct notifier_block *this,
581                   unsigned long event, void *ptr)
582 {
583         struct net_device *dev = ptr;
584
585         /* Drop any packets associated with the downed device */
586         if (event == NETDEV_DOWN)
587                 ipq_dev_drop(dev->ifindex);
588         return NOTIFY_DONE;
589 }
590
591 static struct notifier_block ipq_dev_notifier = {
592         .notifier_call  = ipq_rcv_dev_event,
593 };
594
595 static int
596 ipq_rcv_nl_event(struct notifier_block *this,
597                  unsigned long event, void *ptr)
598 {
599         struct netlink_notify *n = ptr;
600
601         if (event == NETLINK_URELEASE &&
602             n->protocol == NETLINK_FIREWALL && n->pid) {
603                 write_lock_bh(&queue_lock);
604                 if (n->pid == peer_pid)
605                         __ipq_reset();
606                 write_unlock_bh(&queue_lock);
607         }
608         return NOTIFY_DONE;
609 }
610
611 static struct notifier_block ipq_nl_notifier = {
612         .notifier_call  = ipq_rcv_nl_event,
613 };
614
615 static struct ctl_table_header *ipq_sysctl_header;
616
617 static ctl_table ipq_table[] = {
618         {
619                 .ctl_name       = NET_IPQ_QMAX,
620                 .procname       = NET_IPQ_QMAX_NAME,
621                 .data           = &queue_maxlen,
622                 .maxlen         = sizeof(queue_maxlen),
623                 .mode           = 0644,
624                 .proc_handler   = proc_dointvec
625         },
626         { .ctl_name = 0 }
627 };
628
629 static ctl_table ipq_dir_table[] = {
630         {
631                 .ctl_name       = NET_IPV4,
632                 .procname       = "ipv4",
633                 .mode           = 0555,
634                 .child          = ipq_table
635         },
636         { .ctl_name = 0 }
637 };
638
639 static ctl_table ipq_root_table[] = {
640         {
641                 .ctl_name       = CTL_NET,
642                 .procname       = "net",
643                 .mode           = 0555,
644                 .child          = ipq_dir_table
645         },
646         { .ctl_name = 0 }
647 };
648
649 #ifdef CONFIG_PROC_FS
650 static int
651 ipq_get_info(char *buffer, char **start, off_t offset, int length)
652 {
653         int len;
654
655         read_lock_bh(&queue_lock);
656         
657         len = sprintf(buffer,
658                       "Peer PID          : %d\n"
659                       "Copy mode         : %hu\n"
660                       "Copy range        : %u\n"
661                       "Queue length      : %u\n"
662                       "Queue max. length : %u\n"
663                       "Queue dropped     : %u\n"
664                       "Netlink dropped   : %u\n",
665                       peer_pid,
666                       copy_mode,
667                       copy_range,
668                       queue_total,
669                       queue_maxlen,
670                       queue_dropped,
671                       queue_user_dropped);
672
673         read_unlock_bh(&queue_lock);
674         
675         *start = buffer + offset;
676         len -= offset;
677         if (len > length)
678                 len = length;
679         else if (len < 0)
680                 len = 0;
681         return len;
682 }
683 #endif /* CONFIG_PROC_FS */
684
685 static int
686 init_or_cleanup(int init)
687 {
688         int status = -ENOMEM;
689         struct proc_dir_entry *proc;
690         
691         if (!init)
692                 goto cleanup;
693
694         netlink_register_notifier(&ipq_nl_notifier);
695         ipqnl = netlink_kernel_create(NETLINK_FIREWALL, ipq_rcv_sk);
696         if (ipqnl == NULL) {
697                 printk(KERN_ERR "ip_queue: failed to create netlink socket\n");
698                 goto cleanup_netlink_notifier;
699         }
700
701         proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
702         if (proc)
703                 proc->owner = THIS_MODULE;
704         else {
705                 printk(KERN_ERR "ip_queue: failed to create proc entry\n");
706                 goto cleanup_ipqnl;
707         }
708         
709         register_netdevice_notifier(&ipq_dev_notifier);
710         ipq_sysctl_header = register_sysctl_table(ipq_root_table, 0);
711         
712         status = nf_register_queue_handler(PF_INET, ipq_enqueue_packet, NULL);
713         if (status < 0) {
714                 printk(KERN_ERR "ip_queue: failed to register queue handler\n");
715                 goto cleanup_sysctl;
716         }
717         return status;
718
719 cleanup:
720         nf_unregister_queue_handler(PF_INET);
721         synchronize_net();
722         ipq_flush(NF_DROP);
723         
724 cleanup_sysctl:
725         unregister_sysctl_table(ipq_sysctl_header);
726         unregister_netdevice_notifier(&ipq_dev_notifier);
727         proc_net_remove(IPQ_PROC_FS_NAME);
728         
729 cleanup_ipqnl:
730         sock_release(ipqnl->sk_socket);
731         down(&ipqnl_sem);
732         up(&ipqnl_sem);
733         
734 cleanup_netlink_notifier:
735         netlink_unregister_notifier(&ipq_nl_notifier);
736         return status;
737 }
738
739 static int __init init(void)
740 {
741         
742         return init_or_cleanup(1);
743 }
744
745 static void __exit fini(void)
746 {
747         init_or_cleanup(0);
748 }
749
750 MODULE_DESCRIPTION("IPv4 packet queue handler");
751 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
752 MODULE_LICENSE("GPL");
753
754 module_init(init);
755 module_exit(fini);