projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
[NETFILTER]: nfnetlink_log: fix module reference counting
[deliverable/linux.git] / net / netfilter / nfnetlink_log.c
1 /*
2 * This is a module which is used for logging packets to userspace via
3 * nfetlink.
4 *
5 * (C) 2005 by Harald Welte <laforge@netfilter.org>
6 *
7 * Based on the old ipv4-only ipt_ULOG.c:
8 * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 *
14 * 2006-01-26 Harald Welte <laforge@netfilter.org>
15 * - Add optional local and global sequence number to detect lost
16 * events from userspace
17 *
18 */
19 #include <linux/module.h>
20 #include <linux/skbuff.h>
21 #include <linux/init.h>
22 #include <linux/ip.h>
23 #include <linux/ipv6.h>
24 #include <linux/netdevice.h>
25 #include <linux/netfilter.h>
26 #include <linux/netlink.h>
27 #include <linux/netfilter/nfnetlink.h>
28 #include <linux/netfilter/nfnetlink_log.h>
29 #include <linux/spinlock.h>
30 #include <linux/sysctl.h>
31 #include <linux/proc_fs.h>
32 #include <linux/security.h>
33 #include <linux/list.h>
34 #include <linux/jhash.h>
35 #include <linux/random.h>
36 #include <net/sock.h>
37
38 #include <asm/atomic.h>
39
40 #ifdef CONFIG_BRIDGE_NETFILTER
41 #include "../bridge/br_private.h"
42 #endif
43
44 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
45 #define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
46 #define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
47
48 #define PRINTR(x, args...) do { if (net_ratelimit()) \
49 printk(x, ## args); } while (0);
50
51 #if 0
52 #define UDEBUG(x, args ...) printk(KERN_DEBUG "%s(%d):%s(): " x, \
53 __FILE__, __LINE__, __FUNCTION__, \
54 ## args)
55 #else
56 #define UDEBUG(x, ...)
57 #endif
58
59 struct nfulnl_instance {
60 struct hlist_node hlist; /* global list of instances */
61 spinlock_t lock;
62 atomic_t use; /* use count */
63
64 unsigned int qlen; /* number of nlmsgs in skb */
65 struct sk_buff *skb; /* pre-allocatd skb */
66 struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */
67 struct timer_list timer;
68 int peer_pid; /* PID of the peer process */
69
70 /* configurable parameters */
71 unsigned int flushtimeout; /* timeout until queue flush */
72 unsigned int nlbufsiz; /* netlink buffer allocation size */
73 unsigned int qthreshold; /* threshold of the queue */
74 u_int32_t copy_range;
75 u_int32_t seq; /* instance-local sequential counter */
76 u_int16_t group_num; /* number of this queue */
77 u_int16_t flags;
78 u_int8_t copy_mode;
79 };
80
81 static DEFINE_RWLOCK(instances_lock);
82 static atomic_t global_seq;
83
84 #define INSTANCE_BUCKETS 16
85 static struct hlist_head instance_table[INSTANCE_BUCKETS];
86 static unsigned int hash_init;
87
88 static inline u_int8_t instance_hashfn(u_int16_t group_num)
89 {
90 return ((group_num & 0xff) % INSTANCE_BUCKETS);
91 }
92
93 static struct nfulnl_instance *
94 __instance_lookup(u_int16_t group_num)
95 {
96 struct hlist_head *head;
97 struct hlist_node *pos;
98 struct nfulnl_instance *inst;
99
100 UDEBUG("entering (group_num=%u)\n", group_num);
101
102 head = &instance_table[instance_hashfn(group_num)];
103 hlist_for_each_entry(inst, pos, head, hlist) {
104 if (inst->group_num == group_num)
105 return inst;
106 }
107 return NULL;
108 }
109
110 static inline void
111 instance_get(struct nfulnl_instance *inst)
112 {
113 atomic_inc(&inst->use);
114 }
115
116 static struct nfulnl_instance *
117 instance_lookup_get(u_int16_t group_num)
118 {
119 struct nfulnl_instance *inst;
120
121 read_lock_bh(&instances_lock);
122 inst = __instance_lookup(group_num);
123 if (inst)
124 instance_get(inst);
125 read_unlock_bh(&instances_lock);
126
127 return inst;
128 }
129
130 static void
131 instance_put(struct nfulnl_instance *inst)
132 {
133 if (inst && atomic_dec_and_test(&inst->use)) {
134 UDEBUG("kfree(inst=%p)\n", inst);
135 kfree(inst);
136 module_put(THIS_MODULE);
137 }
138 }
139
140 static void nfulnl_timer(unsigned long data);
141
142 static struct nfulnl_instance *
143 instance_create(u_int16_t group_num, int pid)
144 {
145 struct nfulnl_instance *inst;
146
147 UDEBUG("entering (group_num=%u, pid=%d)\n", group_num,
148 pid);
149
150 write_lock_bh(&instances_lock);
151 if (__instance_lookup(group_num)) {
152 inst = NULL;
153 UDEBUG("aborting, instance already exists\n");
154 goto out_unlock;
155 }
156
157 inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
158 if (!inst)
159 goto out_unlock;
160
161 INIT_HLIST_NODE(&inst->hlist);
162 spin_lock_init(&inst->lock);
163 /* needs to be two, since we _put() after creation */
164 atomic_set(&inst->use, 2);
165
166 init_timer(&inst->timer);
167 inst->timer.function = nfulnl_timer;
168 inst->timer.data = (unsigned long)inst;
169 /* don't start timer yet. (re)start it with every packet */
170
171 inst->peer_pid = pid;
172 inst->group_num = group_num;
173
174 inst->qthreshold = NFULNL_QTHRESH_DEFAULT;
175 inst->flushtimeout = NFULNL_TIMEOUT_DEFAULT;
176 inst->nlbufsiz = NFULNL_NLBUFSIZ_DEFAULT;
177 inst->copy_mode = NFULNL_COPY_PACKET;
178 inst->copy_range = 0xffff;
179
180 if (!try_module_get(THIS_MODULE))
181 goto out_free;
182
183 hlist_add_head(&inst->hlist,
184 &instance_table[instance_hashfn(group_num)]);
185
186 UDEBUG("newly added node: %p, next=%p\n", &inst->hlist,
187 inst->hlist.next);
188
189 write_unlock_bh(&instances_lock);
190
191 return inst;
192
193 out_free:
194 instance_put(inst);
195 out_unlock:
196 write_unlock_bh(&instances_lock);
197 return NULL;
198 }
199
200 static int __nfulnl_send(struct nfulnl_instance *inst);
201
202 static void
203 _instance_destroy2(struct nfulnl_instance *inst, int lock)
204 {
205 /* first pull it out of the global list */
206 if (lock)
207 write_lock_bh(&instances_lock);
208
209 UDEBUG("removing instance %p (queuenum=%u) from hash\n",
210 inst, inst->group_num);
211
212 hlist_del(&inst->hlist);
213
214 if (lock)
215 write_unlock_bh(&instances_lock);
216
217 /* then flush all pending packets from skb */
218
219 spin_lock_bh(&inst->lock);
220 if (inst->skb) {
221 if (inst->qlen)
222 __nfulnl_send(inst);
223 if (inst->skb) {
224 kfree_skb(inst->skb);
225 inst->skb = NULL;
226 }
227 }
228 spin_unlock_bh(&inst->lock);
229
230 /* and finally put the refcount */
231 instance_put(inst);
232 }
233
234 static inline void
235 __instance_destroy(struct nfulnl_instance *inst)
236 {
237 _instance_destroy2(inst, 0);
238 }
239
240 static inline void
241 instance_destroy(struct nfulnl_instance *inst)
242 {
243 _instance_destroy2(inst, 1);
244 }
245
246 static int
247 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
248 unsigned int range)
249 {
250 int status = 0;
251
252 spin_lock_bh(&inst->lock);
253
254 switch (mode) {
255 case NFULNL_COPY_NONE:
256 case NFULNL_COPY_META:
257 inst->copy_mode = mode;
258 inst->copy_range = 0;
259 break;
260
261 case NFULNL_COPY_PACKET:
262 inst->copy_mode = mode;
263 /* we're using struct nfattr which has 16bit nfa_len */
264 if (range > 0xffff)
265 inst->copy_range = 0xffff;
266 else
267 inst->copy_range = range;
268 break;
269
270 default:
271 status = -EINVAL;
272 break;
273 }
274
275 spin_unlock_bh(&inst->lock);
276
277 return status;
278 }
279
280 static int
281 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
282 {
283 int status;
284
285 spin_lock_bh(&inst->lock);
286 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
287 status = -ERANGE;
288 else if (nlbufsiz > 131072)
289 status = -ERANGE;
290 else {
291 inst->nlbufsiz = nlbufsiz;
292 status = 0;
293 }
294 spin_unlock_bh(&inst->lock);
295
296 return status;
297 }
298
299 static int
300 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
301 {
302 spin_lock_bh(&inst->lock);
303 inst->flushtimeout = timeout;
304 spin_unlock_bh(&inst->lock);
305
306 return 0;
307 }
308
309 static int
310 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
311 {
312 spin_lock_bh(&inst->lock);
313 inst->qthreshold = qthresh;
314 spin_unlock_bh(&inst->lock);
315
316 return 0;
317 }
318
319 static int
320 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
321 {
322 spin_lock_bh(&inst->lock);
323 inst->flags = flags;
324 spin_unlock_bh(&inst->lock);
325
326 return 0;
327 }
328
329 static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size,
330 unsigned int pkt_size)
331 {
332 struct sk_buff *skb;
333 unsigned int n;
334
335 UDEBUG("entered (%u, %u)\n", inst_size, pkt_size);
336
337 /* alloc skb which should be big enough for a whole multipart
338 * message. WARNING: has to be <= 128k due to slab restrictions */
339
340 n = max(inst_size, pkt_size);
341 skb = alloc_skb(n, GFP_ATOMIC);
342 if (!skb) {
343 PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
344 inst_size);
345
346 if (n > pkt_size) {
347 /* try to allocate only as much as we need for current
348 * packet */
349
350 skb = alloc_skb(pkt_size, GFP_ATOMIC);
351 if (!skb)
352 PRINTR("nfnetlink_log: can't even alloc %u "
353 "bytes\n", pkt_size);
354 }
355 }
356
357 return skb;
358 }
359
360 static int
361 __nfulnl_send(struct nfulnl_instance *inst)
362 {
363 int status;
364
365 if (timer_pending(&inst->timer))
366 del_timer(&inst->timer);
367
368 if (!inst->skb)
369 return 0;
370
371 if (inst->qlen > 1)
372 inst->lastnlh->nlmsg_type = NLMSG_DONE;
373
374 status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
375 if (status < 0) {
376 UDEBUG("netlink_unicast() failed\n");
377 /* FIXME: statistics */
378 }
379
380 inst->qlen = 0;
381 inst->skb = NULL;
382 inst->lastnlh = NULL;
383
384 return status;
385 }
386
387 static void nfulnl_timer(unsigned long data)
388 {
389 struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
390
391 UDEBUG("timer function called, flushing buffer\n");
392
393 spin_lock_bh(&inst->lock);
394 __nfulnl_send(inst);
395 spin_unlock_bh(&inst->lock);
396 instance_put(inst);
397 }
398
399 /* This is an inline function, we don't really care about a long
400 * list of arguments */
401 static inline int
402 __build_packet_message(struct nfulnl_instance *inst,
403 const struct sk_buff *skb,
404 unsigned int data_len,
405 unsigned int pf,
406 unsigned int hooknum,
407 const struct net_device *indev,
408 const struct net_device *outdev,
409 const struct nf_loginfo *li,
410 const char *prefix, unsigned int plen)
411 {
412 unsigned char *old_tail;
413 struct nfulnl_msg_packet_hdr pmsg;
414 struct nlmsghdr *nlh;
415 struct nfgenmsg *nfmsg;
416 __be32 tmp_uint;
417
418 UDEBUG("entered\n");
419
420 old_tail = inst->skb->tail;
421 nlh = NLMSG_PUT(inst->skb, 0, 0,
422 NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
423 sizeof(struct nfgenmsg));
424 nfmsg = NLMSG_DATA(nlh);
425 nfmsg->nfgen_family = pf;
426 nfmsg->version = NFNETLINK_V0;
427 nfmsg->res_id = htons(inst->group_num);
428
429 pmsg.hw_protocol = skb->protocol;
430 pmsg.hook = hooknum;
431
432 NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
433
434 if (prefix)
435 NFA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
436
437 if (indev) {
438 tmp_uint = htonl(indev->ifindex);
439 #ifndef CONFIG_BRIDGE_NETFILTER
440 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
441 &tmp_uint);
442 #else
443 if (pf == PF_BRIDGE) {
444 /* Case 1: outdev is physical input device, we need to
445 * look for bridge group (when called from
446 * netfilter_bridge) */
447 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
448 sizeof(tmp_uint), &tmp_uint);
449 /* this is the bridge group "brX" */
450 tmp_uint = htonl(indev->br_port->br->dev->ifindex);
451 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
452 sizeof(tmp_uint), &tmp_uint);
453 } else {
454 /* Case 2: indev is bridge group, we need to look for
455 * physical device (when called from ipv4) */
456 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
457 sizeof(tmp_uint), &tmp_uint);
458 if (skb->nf_bridge && skb->nf_bridge->physindev) {
459 tmp_uint =
460 htonl(skb->nf_bridge->physindev->ifindex);
461 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
462 sizeof(tmp_uint), &tmp_uint);
463 }
464 }
465 #endif
466 }
467
468 if (outdev) {
469 tmp_uint = htonl(outdev->ifindex);
470 #ifndef CONFIG_BRIDGE_NETFILTER
471 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
472 &tmp_uint);
473 #else
474 if (pf == PF_BRIDGE) {
475 /* Case 1: outdev is physical output device, we need to
476 * look for bridge group (when called from
477 * netfilter_bridge) */
478 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
479 sizeof(tmp_uint), &tmp_uint);
480 /* this is the bridge group "brX" */
481 tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
482 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
483 sizeof(tmp_uint), &tmp_uint);
484 } else {
485 /* Case 2: indev is a bridge group, we need to look
486 * for physical device (when called from ipv4) */
487 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
488 sizeof(tmp_uint), &tmp_uint);
489 if (skb->nf_bridge) {
490 tmp_uint =
491 htonl(skb->nf_bridge->physoutdev->ifindex);
492 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
493 sizeof(tmp_uint), &tmp_uint);
494 }
495 }
496 #endif
497 }
498
499 if (skb->mark) {
500 tmp_uint = htonl(skb->mark);
501 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
502 }
503
504 if (indev && skb->dev && skb->dev->hard_header_parse) {
505 struct nfulnl_msg_packet_hw phw;
506 int len = skb->dev->hard_header_parse((struct sk_buff *)skb,
507 phw.hw_addr);
508 phw.hw_addrlen = htons(len);
509 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
510 }
511
512 if (skb->tstamp.off_sec) {
513 struct nfulnl_msg_packet_timestamp ts;
514
515 ts.sec = cpu_to_be64(skb->tstamp.off_sec);
516 ts.usec = cpu_to_be64(skb->tstamp.off_usec);
517
518 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
519 }
520
521 /* UID */
522 if (skb->sk) {
523 read_lock_bh(&skb->sk->sk_callback_lock);
524 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
525 __be32 uid = htonl(skb->sk->sk_socket->file->f_uid);
526 /* need to unlock here since NFA_PUT may goto */
527 read_unlock_bh(&skb->sk->sk_callback_lock);
528 NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
529 } else
530 read_unlock_bh(&skb->sk->sk_callback_lock);
531 }
532
533 /* local sequence number */
534 if (inst->flags & NFULNL_CFG_F_SEQ) {
535 tmp_uint = htonl(inst->seq++);
536 NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
537 }
538 /* global sequence number */
539 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
540 tmp_uint = htonl(atomic_inc_return(&global_seq));
541 NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
542 }
543
544 if (data_len) {
545 struct nfattr *nfa;
546 int size = NFA_LENGTH(data_len);
547
548 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
549 printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
550 goto nlmsg_failure;
551 }
552
553 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
554 nfa->nfa_type = NFULA_PAYLOAD;
555 nfa->nfa_len = size;
556
557 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
558 BUG();
559 }
560
561 nlh->nlmsg_len = inst->skb->tail - old_tail;
562 inst->lastnlh = nlh;
563 return 0;
564
565 nlmsg_failure:
566 UDEBUG("nlmsg_failure\n");
567 nfattr_failure:
568 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
569 return -1;
570 }
571
572 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
573
574 static struct nf_loginfo default_loginfo = {
575 .type = NF_LOG_TYPE_ULOG,
576 .u = {
577 .ulog = {
578 .copy_len = 0xffff,
579 .group = 0,
580 .qthreshold = 1,
581 },
582 },
583 };
584
585 /* log handler for internal netfilter logging api */
586 static void
587 nfulnl_log_packet(unsigned int pf,
588 unsigned int hooknum,
589 const struct sk_buff *skb,
590 const struct net_device *in,
591 const struct net_device *out,
592 const struct nf_loginfo *li_user,
593 const char *prefix)
594 {
595 unsigned int size, data_len;
596 struct nfulnl_instance *inst;
597 const struct nf_loginfo *li;
598 unsigned int qthreshold;
599 unsigned int nlbufsiz;
600 unsigned int plen;
601
602 if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
603 li = li_user;
604 else
605 li = &default_loginfo;
606
607 inst = instance_lookup_get(li->u.ulog.group);
608 if (!inst)
609 inst = instance_lookup_get(0);
610 if (!inst) {
611 PRINTR("nfnetlink_log: trying to log packet, "
612 "but no instance for group %u\n", li->u.ulog.group);
613 return;
614 }
615
616 plen = 0;
617 if (prefix)
618 plen = strlen(prefix);
619
620 /* all macros expand to constant values at compile time */
621 /* FIXME: do we want to make the size calculation conditional based on
622 * what is actually present? way more branches and checks, but more
623 * memory efficient... */
624 size = NLMSG_SPACE(sizeof(struct nfgenmsg))
625 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
626 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
627 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
628 #ifdef CONFIG_BRIDGE_NETFILTER
629 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
630 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
631 #endif
632 + NFA_SPACE(sizeof(u_int32_t)) /* mark */
633 + NFA_SPACE(sizeof(u_int32_t)) /* uid */
634 + NFA_SPACE(plen) /* prefix */
635 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
636 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
637
638 UDEBUG("initial size=%u\n", size);
639
640 spin_lock_bh(&inst->lock);
641
642 if (inst->flags & NFULNL_CFG_F_SEQ)
643 size += NFA_SPACE(sizeof(u_int32_t));
644 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
645 size += NFA_SPACE(sizeof(u_int32_t));
646
647 qthreshold = inst->qthreshold;
648 /* per-rule qthreshold overrides per-instance */
649 if (qthreshold > li->u.ulog.qthreshold)
650 qthreshold = li->u.ulog.qthreshold;
651
652 switch (inst->copy_mode) {
653 case NFULNL_COPY_META:
654 case NFULNL_COPY_NONE:
655 data_len = 0;
656 break;
657
658 case NFULNL_COPY_PACKET:
659 if (inst->copy_range == 0
660 || inst->copy_range > skb->len)
661 data_len = skb->len;
662 else
663 data_len = inst->copy_range;
664
665 size += NFA_SPACE(data_len);
666 UDEBUG("copy_packet, therefore size now %u\n", size);
667 break;
668
669 default:
670 spin_unlock_bh(&inst->lock);
671 instance_put(inst);
672 return;
673 }
674
675 if (size > inst->nlbufsiz)
676 nlbufsiz = size;
677 else
678 nlbufsiz = inst->nlbufsiz;
679
680 if (!inst->skb) {
681 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
682 UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
683 inst->nlbufsiz, size);
684 goto alloc_failure;
685 }
686 } else if (inst->qlen >= qthreshold ||
687 size > skb_tailroom(inst->skb)) {
688 /* either the queue len is too high or we don't have
689 * enough room in the skb left. flush to userspace. */
690 UDEBUG("flushing old skb\n");
691
692 __nfulnl_send(inst);
693
694 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
695 UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
696 inst->nlbufsiz, size);
697 goto alloc_failure;
698 }
699 }
700
701 UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
702 inst->qlen++;
703
704 __build_packet_message(inst, skb, data_len, pf,
705 hooknum, in, out, li, prefix, plen);
706
707 /* timer_pending always called within inst->lock, so there
708 * is no chance of a race here */
709 if (!timer_pending(&inst->timer)) {
710 instance_get(inst);
711 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
712 add_timer(&inst->timer);
713 }
714
715 unlock_and_release:
716 spin_unlock_bh(&inst->lock);
717 instance_put(inst);
718 return;
719
720 alloc_failure:
721 UDEBUG("error allocating skb\n");
722 /* FIXME: statistics */
723 goto unlock_and_release;
724 }
725
726 static int
727 nfulnl_rcv_nl_event(struct notifier_block *this,
728 unsigned long event, void *ptr)
729 {
730 struct netlink_notify *n = ptr;
731
732 if (event == NETLINK_URELEASE &&
733 n->protocol == NETLINK_NETFILTER && n->pid) {
734 int i;
735
736 /* destroy all instances for this pid */
737 write_lock_bh(&instances_lock);
738 for (i = 0; i < INSTANCE_BUCKETS; i++) {
739 struct hlist_node *tmp, *t2;
740 struct nfulnl_instance *inst;
741 struct hlist_head *head = &instance_table[i];
742
743 hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
744 UDEBUG("node = %p\n", inst);
745 if (n->pid == inst->peer_pid)
746 __instance_destroy(inst);
747 }
748 }
749 write_unlock_bh(&instances_lock);
750 }
751 return NOTIFY_DONE;
752 }
753
754 static struct notifier_block nfulnl_rtnl_notifier = {
755 .notifier_call = nfulnl_rcv_nl_event,
756 };
757
758 static int
759 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
760 struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
761 {
762 return -ENOTSUPP;
763 }
764
765 static struct nf_logger nfulnl_logger = {
766 .name = "nfnetlink_log",
767 .logfn = &nfulnl_log_packet,
768 .me = THIS_MODULE,
769 };
770
771 static const int nfula_min[NFULA_MAX] = {
772 [NFULA_PACKET_HDR-1] = sizeof(struct nfulnl_msg_packet_hdr),
773 [NFULA_MARK-1] = sizeof(u_int32_t),
774 [NFULA_TIMESTAMP-1] = sizeof(struct nfulnl_msg_packet_timestamp),
775 [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
776 [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
777 [NFULA_IFINDEX_PHYSINDEV-1] = sizeof(u_int32_t),
778 [NFULA_IFINDEX_PHYSOUTDEV-1] = sizeof(u_int32_t),
779 [NFULA_HWADDR-1] = sizeof(struct nfulnl_msg_packet_hw),
780 [NFULA_PAYLOAD-1] = 0,
781 [NFULA_PREFIX-1] = 0,
782 [NFULA_UID-1] = sizeof(u_int32_t),
783 [NFULA_SEQ-1] = sizeof(u_int32_t),
784 [NFULA_SEQ_GLOBAL-1] = sizeof(u_int32_t),
785 };
786
787 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
788 [NFULA_CFG_CMD-1] = sizeof(struct nfulnl_msg_config_cmd),
789 [NFULA_CFG_MODE-1] = sizeof(struct nfulnl_msg_config_mode),
790 [NFULA_CFG_TIMEOUT-1] = sizeof(u_int32_t),
791 [NFULA_CFG_QTHRESH-1] = sizeof(u_int32_t),
792 [NFULA_CFG_NLBUFSIZ-1] = sizeof(u_int32_t),
793 [NFULA_CFG_FLAGS-1] = sizeof(u_int16_t),
794 };
795
796 static int
797 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
798 struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
799 {
800 struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
801 u_int16_t group_num = ntohs(nfmsg->res_id);
802 struct nfulnl_instance *inst;
803 int ret = 0;
804
805 UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
806
807 if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
808 UDEBUG("bad attribute size\n");
809 return -EINVAL;
810 }
811
812 inst = instance_lookup_get(group_num);
813 if (nfula[NFULA_CFG_CMD-1]) {
814 u_int8_t pf = nfmsg->nfgen_family;
815 struct nfulnl_msg_config_cmd *cmd;
816 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
817 UDEBUG("found CFG_CMD for\n");
818
819 switch (cmd->command) {
820 case NFULNL_CFG_CMD_BIND:
821 if (inst) {
822 ret = -EBUSY;
823 goto out_put;
824 }
825
826 inst = instance_create(group_num,
827 NETLINK_CB(skb).pid);
828 if (!inst) {
829 ret = -EINVAL;
830 goto out_put;
831 }
832 break;
833 case NFULNL_CFG_CMD_UNBIND:
834 if (!inst) {
835 ret = -ENODEV;
836 goto out_put;
837 }
838
839 if (inst->peer_pid != NETLINK_CB(skb).pid) {
840 ret = -EPERM;
841 goto out_put;
842 }
843
844 instance_destroy(inst);
845 break;
846 case NFULNL_CFG_CMD_PF_BIND:
847 UDEBUG("registering log handler for pf=%u\n", pf);
848 ret = nf_log_register(pf, &nfulnl_logger);
849 break;
850 case NFULNL_CFG_CMD_PF_UNBIND:
851 UDEBUG("unregistering log handler for pf=%u\n", pf);
852 /* This is a bug and a feature. We cannot unregister
853 * other handlers, like nfnetlink_inst can */
854 nf_log_unregister_pf(pf);
855 break;
856 default:
857 ret = -EINVAL;
858 break;
859 }
860
861 if (!inst)
862 goto out;
863 } else {
864 if (!inst) {
865 UDEBUG("no config command, and no instance for "
866 "group=%u pid=%u =>ENOENT\n",
867 group_num, NETLINK_CB(skb).pid);
868 ret = -ENOENT;
869 goto out_put;
870 }
871
872 if (inst->peer_pid != NETLINK_CB(skb).pid) {
873 UDEBUG("no config command, and wrong pid\n");
874 ret = -EPERM;
875 goto out_put;
876 }
877 }
878
879 if (nfula[NFULA_CFG_MODE-1]) {
880 struct nfulnl_msg_config_mode *params;
881 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
882
883 nfulnl_set_mode(inst, params->copy_mode,
884 ntohl(params->copy_range));
885 }
886
887 if (nfula[NFULA_CFG_TIMEOUT-1]) {
888 __be32 timeout =
889 *(__be32 *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
890
891 nfulnl_set_timeout(inst, ntohl(timeout));
892 }
893
894 if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
895 __be32 nlbufsiz =
896 *(__be32 *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
897
898 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
899 }
900
901 if (nfula[NFULA_CFG_QTHRESH-1]) {
902 __be32 qthresh =
903 *(__be32 *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
904
905 nfulnl_set_qthresh(inst, ntohl(qthresh));
906 }
907
908 if (nfula[NFULA_CFG_FLAGS-1]) {
909 __be16 flags =
910 *(__be16 *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
911 nfulnl_set_flags(inst, ntohs(flags));
912 }
913
914 out_put:
915 instance_put(inst);
916 out:
917 return ret;
918 }
919
920 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
921 [NFULNL_MSG_PACKET] = { .call = nfulnl_recv_unsupp,
922 .attr_count = NFULA_MAX, },
923 [NFULNL_MSG_CONFIG] = { .call = nfulnl_recv_config,
924 .attr_count = NFULA_CFG_MAX, },
925 };
926
927 static struct nfnetlink_subsystem nfulnl_subsys = {
928 .name = "log",
929 .subsys_id = NFNL_SUBSYS_ULOG,
930 .cb_count = NFULNL_MSG_MAX,
931 .cb = nfulnl_cb,
932 };
933
934 #ifdef CONFIG_PROC_FS
935 struct iter_state {
936 unsigned int bucket;
937 };
938
939 static struct hlist_node *get_first(struct seq_file *seq)
940 {
941 struct iter_state *st = seq->private;
942
943 if (!st)
944 return NULL;
945
946 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
947 if (!hlist_empty(&instance_table[st->bucket]))
948 return instance_table[st->bucket].first;
949 }
950 return NULL;
951 }
952
953 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
954 {
955 struct iter_state *st = seq->private;
956
957 h = h->next;
958 while (!h) {
959 if (++st->bucket >= INSTANCE_BUCKETS)
960 return NULL;
961
962 h = instance_table[st->bucket].first;
963 }
964 return h;
965 }
966
967 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
968 {
969 struct hlist_node *head;
970 head = get_first(seq);
971
972 if (head)
973 while (pos && (head = get_next(seq, head)))
974 pos--;
975 return pos ? NULL : head;
976 }
977
978 static void *seq_start(struct seq_file *seq, loff_t *pos)
979 {
980 read_lock_bh(&instances_lock);
981 return get_idx(seq, *pos);
982 }
983
984 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
985 {
986 (*pos)++;
987 return get_next(s, v);
988 }
989
990 static void seq_stop(struct seq_file *s, void *v)
991 {
992 read_unlock_bh(&instances_lock);
993 }
994
995 static int seq_show(struct seq_file *s, void *v)
996 {
997 const struct nfulnl_instance *inst = v;
998
999 return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
1000 inst->group_num,
1001 inst->peer_pid, inst->qlen,
1002 inst->copy_mode, inst->copy_range,
1003 inst->flushtimeout, atomic_read(&inst->use));
1004 }
1005
1006 static struct seq_operations nful_seq_ops = {
1007 .start = seq_start,
1008 .next = seq_next,
1009 .stop = seq_stop,
1010 .show = seq_show,
1011 };
1012
1013 static int nful_open(struct inode *inode, struct file *file)
1014 {
1015 struct seq_file *seq;
1016 struct iter_state *is;
1017 int ret;
1018
1019 is = kzalloc(sizeof(*is), GFP_KERNEL);
1020 if (!is)
1021 return -ENOMEM;
1022 ret = seq_open(file, &nful_seq_ops);
1023 if (ret < 0)
1024 goto out_free;
1025 seq = file->private_data;
1026 seq->private = is;
1027 return ret;
1028 out_free:
1029 kfree(is);
1030 return ret;
1031 }
1032
1033 static const struct file_operations nful_file_ops = {
1034 .owner = THIS_MODULE,
1035 .open = nful_open,
1036 .read = seq_read,
1037 .llseek = seq_lseek,
1038 .release = seq_release_private,
1039 };
1040
1041 #endif /* PROC_FS */
1042
1043 static int __init nfnetlink_log_init(void)
1044 {
1045 int i, status = -ENOMEM;
1046 #ifdef CONFIG_PROC_FS
1047 struct proc_dir_entry *proc_nful;
1048 #endif
1049
1050 for (i = 0; i < INSTANCE_BUCKETS; i++)
1051 INIT_HLIST_HEAD(&instance_table[i]);
1052
1053 /* it's not really all that important to have a random value, so
1054 * we can do this from the init function, even if there hasn't
1055 * been that much entropy yet */
1056 get_random_bytes(&hash_init, sizeof(hash_init));
1057
1058 netlink_register_notifier(&nfulnl_rtnl_notifier);
1059 status = nfnetlink_subsys_register(&nfulnl_subsys);
1060 if (status < 0) {
1061 printk(KERN_ERR "log: failed to create netlink socket\n");
1062 goto cleanup_netlink_notifier;
1063 }
1064
1065 #ifdef CONFIG_PROC_FS
1066 proc_nful = create_proc_entry("nfnetlink_log", 0440,
1067 proc_net_netfilter);
1068 if (!proc_nful)
1069 goto cleanup_subsys;
1070 proc_nful->proc_fops = &nful_file_ops;
1071 #endif
1072 return status;
1073
1074 #ifdef CONFIG_PROC_FS
1075 cleanup_subsys:
1076 nfnetlink_subsys_unregister(&nfulnl_subsys);
1077 #endif
1078 cleanup_netlink_notifier:
1079 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1080 return status;
1081 }
1082
1083 static void __exit nfnetlink_log_fini(void)
1084 {
1085 nf_log_unregister(&nfulnl_logger);
1086 #ifdef CONFIG_PROC_FS
1087 remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1088 #endif
1089 nfnetlink_subsys_unregister(&nfulnl_subsys);
1090 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1091 }
1092
1093 MODULE_DESCRIPTION("netfilter userspace logging");
1094 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1095 MODULE_LICENSE("GPL");
1096 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1097
1098 module_init(nfnetlink_log_init);
1099 module_exit(nfnetlink_log_fini);
Linux kernel - Deliverables
This page took 0.05255 seconds and 6 git commands to generate.