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[NETFILTER]: nfnetlink_log: don't count max(a,b) twice
[mirror_ubuntu-zesty-kernel.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 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/init.h>
17 #include <linux/ip.h>
18 #include <linux/ipv6.h>
19 #include <linux/netdevice.h>
20 #include <linux/netfilter.h>
21 #include <linux/netlink.h>
22 #include <linux/netfilter/nfnetlink.h>
23 #include <linux/netfilter/nfnetlink_log.h>
24 #include <linux/spinlock.h>
25 #include <linux/sysctl.h>
26 #include <linux/proc_fs.h>
27 #include <linux/security.h>
28 #include <linux/list.h>
29 #include <linux/jhash.h>
30 #include <linux/random.h>
31 #include <net/sock.h>
32
33 #include <asm/atomic.h>
34
35 #ifdef CONFIG_BRIDGE_NETFILTER
36 #include "../bridge/br_private.h"
37 #endif
38
39 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
40 #define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
41 #define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
42
43 #define PRINTR(x, args...) do { if (net_ratelimit()) \
44 printk(x, ## args); } while (0);
45
46 #if 0
47 #define UDEBUG(x, args ...) printk(KERN_DEBUG "%s(%d):%s(): " x, \
48 __FILE__, __LINE__, __FUNCTION__, \
49 ## args)
50 #else
51 #define UDEBUG(x, ...)
52 #endif
53
54 struct nfulnl_instance {
55 struct hlist_node hlist; /* global list of instances */
56 spinlock_t lock;
57 atomic_t use; /* use count */
58
59 unsigned int qlen; /* number of nlmsgs in skb */
60 struct sk_buff *skb; /* pre-allocatd skb */
61 struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */
62 struct timer_list timer;
63 int peer_pid; /* PID of the peer process */
64
65 /* configurable parameters */
66 unsigned int flushtimeout; /* timeout until queue flush */
67 unsigned int nlbufsiz; /* netlink buffer allocation size */
68 unsigned int qthreshold; /* threshold of the queue */
69 u_int32_t copy_range;
70 u_int32_t seq; /* instance-local sequential counter */
71 u_int16_t group_num; /* number of this queue */
72 u_int16_t flags;
73 u_int8_t copy_mode;
74 };
75
76 static DEFINE_RWLOCK(instances_lock);
77 static atomic_t global_seq;
78
79 #define INSTANCE_BUCKETS 16
80 static struct hlist_head instance_table[INSTANCE_BUCKETS];
81 static unsigned int hash_init;
82
83 static inline u_int8_t instance_hashfn(u_int16_t group_num)
84 {
85 return ((group_num & 0xff) % INSTANCE_BUCKETS);
86 }
87
88 static struct nfulnl_instance *
89 __instance_lookup(u_int16_t group_num)
90 {
91 struct hlist_head *head;
92 struct hlist_node *pos;
93 struct nfulnl_instance *inst;
94
95 UDEBUG("entering (group_num=%u)\n", group_num);
96
97 head = &instance_table[instance_hashfn(group_num)];
98 hlist_for_each_entry(inst, pos, head, hlist) {
99 if (inst->group_num == group_num)
100 return inst;
101 }
102 return NULL;
103 }
104
105 static inline void
106 instance_get(struct nfulnl_instance *inst)
107 {
108 atomic_inc(&inst->use);
109 }
110
111 static struct nfulnl_instance *
112 instance_lookup_get(u_int16_t group_num)
113 {
114 struct nfulnl_instance *inst;
115
116 read_lock_bh(&instances_lock);
117 inst = __instance_lookup(group_num);
118 if (inst)
119 instance_get(inst);
120 read_unlock_bh(&instances_lock);
121
122 return inst;
123 }
124
125 static void
126 instance_put(struct nfulnl_instance *inst)
127 {
128 if (inst && atomic_dec_and_test(&inst->use)) {
129 UDEBUG("kfree(inst=%p)\n", inst);
130 kfree(inst);
131 module_put(THIS_MODULE);
132 }
133 }
134
135 static void nfulnl_timer(unsigned long data);
136
137 static struct nfulnl_instance *
138 instance_create(u_int16_t group_num, int pid)
139 {
140 struct nfulnl_instance *inst;
141
142 UDEBUG("entering (group_num=%u, pid=%d)\n", group_num,
143 pid);
144
145 write_lock_bh(&instances_lock);
146 if (__instance_lookup(group_num)) {
147 inst = NULL;
148 UDEBUG("aborting, instance already exists\n");
149 goto out_unlock;
150 }
151
152 inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
153 if (!inst)
154 goto out_unlock;
155
156 INIT_HLIST_NODE(&inst->hlist);
157 spin_lock_init(&inst->lock);
158 /* needs to be two, since we _put() after creation */
159 atomic_set(&inst->use, 2);
160
161 init_timer(&inst->timer);
162 inst->timer.function = nfulnl_timer;
163 inst->timer.data = (unsigned long)inst;
164 /* don't start timer yet. (re)start it with every packet */
165
166 inst->peer_pid = pid;
167 inst->group_num = group_num;
168
169 inst->qthreshold = NFULNL_QTHRESH_DEFAULT;
170 inst->flushtimeout = NFULNL_TIMEOUT_DEFAULT;
171 inst->nlbufsiz = NFULNL_NLBUFSIZ_DEFAULT;
172 inst->copy_mode = NFULNL_COPY_PACKET;
173 inst->copy_range = 0xffff;
174
175 if (!try_module_get(THIS_MODULE))
176 goto out_free;
177
178 hlist_add_head(&inst->hlist,
179 &instance_table[instance_hashfn(group_num)]);
180
181 UDEBUG("newly added node: %p, next=%p\n", &inst->hlist,
182 inst->hlist.next);
183
184 write_unlock_bh(&instances_lock);
185
186 return inst;
187
188 out_free:
189 instance_put(inst);
190 out_unlock:
191 write_unlock_bh(&instances_lock);
192 return NULL;
193 }
194
195 static int __nfulnl_send(struct nfulnl_instance *inst);
196
197 static void
198 _instance_destroy2(struct nfulnl_instance *inst, int lock)
199 {
200 /* first pull it out of the global list */
201 if (lock)
202 write_lock_bh(&instances_lock);
203
204 UDEBUG("removing instance %p (queuenum=%u) from hash\n",
205 inst, inst->group_num);
206
207 hlist_del(&inst->hlist);
208
209 if (lock)
210 write_unlock_bh(&instances_lock);
211
212 /* then flush all pending packets from skb */
213
214 spin_lock_bh(&inst->lock);
215 if (inst->skb) {
216 /* timer "holds" one reference (we have one more) */
217 if (del_timer(&inst->timer))
218 instance_put(inst);
219 if (inst->qlen)
220 __nfulnl_send(inst);
221 if (inst->skb) {
222 kfree_skb(inst->skb);
223 inst->skb = NULL;
224 }
225 }
226 spin_unlock_bh(&inst->lock);
227
228 /* and finally put the refcount */
229 instance_put(inst);
230 }
231
232 static inline void
233 __instance_destroy(struct nfulnl_instance *inst)
234 {
235 _instance_destroy2(inst, 0);
236 }
237
238 static inline void
239 instance_destroy(struct nfulnl_instance *inst)
240 {
241 _instance_destroy2(inst, 1);
242 }
243
244 static int
245 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
246 unsigned int range)
247 {
248 int status = 0;
249
250 spin_lock_bh(&inst->lock);
251
252 switch (mode) {
253 case NFULNL_COPY_NONE:
254 case NFULNL_COPY_META:
255 inst->copy_mode = mode;
256 inst->copy_range = 0;
257 break;
258
259 case NFULNL_COPY_PACKET:
260 inst->copy_mode = mode;
261 /* we're using struct nfattr which has 16bit nfa_len */
262 if (range > 0xffff)
263 inst->copy_range = 0xffff;
264 else
265 inst->copy_range = range;
266 break;
267
268 default:
269 status = -EINVAL;
270 break;
271 }
272
273 spin_unlock_bh(&inst->lock);
274
275 return status;
276 }
277
278 static int
279 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
280 {
281 int status;
282
283 spin_lock_bh(&inst->lock);
284 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
285 status = -ERANGE;
286 else if (nlbufsiz > 131072)
287 status = -ERANGE;
288 else {
289 inst->nlbufsiz = nlbufsiz;
290 status = 0;
291 }
292 spin_unlock_bh(&inst->lock);
293
294 return status;
295 }
296
297 static int
298 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
299 {
300 spin_lock_bh(&inst->lock);
301 inst->flushtimeout = timeout;
302 spin_unlock_bh(&inst->lock);
303
304 return 0;
305 }
306
307 static int
308 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
309 {
310 spin_lock_bh(&inst->lock);
311 inst->qthreshold = qthresh;
312 spin_unlock_bh(&inst->lock);
313
314 return 0;
315 }
316
317 static int
318 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
319 {
320 spin_lock_bh(&inst->lock);
321 inst->flags = flags;
322 spin_unlock_bh(&inst->lock);
323
324 return 0;
325 }
326
327 static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size,
328 unsigned int pkt_size)
329 {
330 struct sk_buff *skb;
331 unsigned int n;
332
333 UDEBUG("entered (%u, %u)\n", inst_size, pkt_size);
334
335 /* alloc skb which should be big enough for a whole multipart
336 * message. WARNING: has to be <= 128k due to slab restrictions */
337
338 n = max(inst_size, pkt_size);
339 skb = alloc_skb(n, GFP_ATOMIC);
340 if (!skb) {
341 PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
342 inst_size);
343
344 if (n > pkt_size) {
345 /* try to allocate only as much as we need for current
346 * packet */
347
348 skb = alloc_skb(pkt_size, GFP_ATOMIC);
349 if (!skb)
350 PRINTR("nfnetlink_log: can't even alloc %u "
351 "bytes\n", pkt_size);
352 }
353 }
354
355 return skb;
356 }
357
358 static int
359 __nfulnl_send(struct nfulnl_instance *inst)
360 {
361 int status;
362
363 if (!inst->skb)
364 return 0;
365
366 if (inst->qlen > 1)
367 inst->lastnlh->nlmsg_type = NLMSG_DONE;
368
369 status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
370 if (status < 0) {
371 UDEBUG("netlink_unicast() failed\n");
372 /* FIXME: statistics */
373 }
374
375 inst->qlen = 0;
376 inst->skb = NULL;
377 inst->lastnlh = NULL;
378
379 return status;
380 }
381
382 static void nfulnl_timer(unsigned long data)
383 {
384 struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
385
386 UDEBUG("timer function called, flushing buffer\n");
387
388 spin_lock_bh(&inst->lock);
389 __nfulnl_send(inst);
390 spin_unlock_bh(&inst->lock);
391 instance_put(inst);
392 }
393
394 /* This is an inline function, we don't really care about a long
395 * list of arguments */
396 static inline int
397 __build_packet_message(struct nfulnl_instance *inst,
398 const struct sk_buff *skb,
399 unsigned int data_len,
400 unsigned int pf,
401 unsigned int hooknum,
402 const struct net_device *indev,
403 const struct net_device *outdev,
404 const struct nf_loginfo *li,
405 const char *prefix, unsigned int plen)
406 {
407 struct nfulnl_msg_packet_hdr pmsg;
408 struct nlmsghdr *nlh;
409 struct nfgenmsg *nfmsg;
410 __be32 tmp_uint;
411 sk_buff_data_t old_tail = inst->skb->tail;
412
413 UDEBUG("entered\n");
414
415 nlh = NLMSG_PUT(inst->skb, 0, 0,
416 NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
417 sizeof(struct nfgenmsg));
418 nfmsg = NLMSG_DATA(nlh);
419 nfmsg->nfgen_family = pf;
420 nfmsg->version = NFNETLINK_V0;
421 nfmsg->res_id = htons(inst->group_num);
422
423 pmsg.hw_protocol = skb->protocol;
424 pmsg.hook = hooknum;
425
426 NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
427
428 if (prefix)
429 NFA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
430
431 if (indev) {
432 tmp_uint = htonl(indev->ifindex);
433 #ifndef CONFIG_BRIDGE_NETFILTER
434 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
435 &tmp_uint);
436 #else
437 if (pf == PF_BRIDGE) {
438 /* Case 1: outdev is physical input device, we need to
439 * look for bridge group (when called from
440 * netfilter_bridge) */
441 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
442 sizeof(tmp_uint), &tmp_uint);
443 /* this is the bridge group "brX" */
444 tmp_uint = htonl(indev->br_port->br->dev->ifindex);
445 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
446 sizeof(tmp_uint), &tmp_uint);
447 } else {
448 /* Case 2: indev is bridge group, we need to look for
449 * physical device (when called from ipv4) */
450 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
451 sizeof(tmp_uint), &tmp_uint);
452 if (skb->nf_bridge && skb->nf_bridge->physindev) {
453 tmp_uint =
454 htonl(skb->nf_bridge->physindev->ifindex);
455 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
456 sizeof(tmp_uint), &tmp_uint);
457 }
458 }
459 #endif
460 }
461
462 if (outdev) {
463 tmp_uint = htonl(outdev->ifindex);
464 #ifndef CONFIG_BRIDGE_NETFILTER
465 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
466 &tmp_uint);
467 #else
468 if (pf == PF_BRIDGE) {
469 /* Case 1: outdev is physical output device, we need to
470 * look for bridge group (when called from
471 * netfilter_bridge) */
472 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
473 sizeof(tmp_uint), &tmp_uint);
474 /* this is the bridge group "brX" */
475 tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
476 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
477 sizeof(tmp_uint), &tmp_uint);
478 } else {
479 /* Case 2: indev is a bridge group, we need to look
480 * for physical device (when called from ipv4) */
481 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
482 sizeof(tmp_uint), &tmp_uint);
483 if (skb->nf_bridge && skb->nf_bridge->physoutdev) {
484 tmp_uint =
485 htonl(skb->nf_bridge->physoutdev->ifindex);
486 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
487 sizeof(tmp_uint), &tmp_uint);
488 }
489 }
490 #endif
491 }
492
493 if (skb->mark) {
494 tmp_uint = htonl(skb->mark);
495 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
496 }
497
498 if (indev && skb->dev && skb->dev->hard_header_parse) {
499 struct nfulnl_msg_packet_hw phw;
500 int len = skb->dev->hard_header_parse((struct sk_buff *)skb,
501 phw.hw_addr);
502 phw.hw_addrlen = htons(len);
503 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
504 }
505
506 if (skb->tstamp.tv64) {
507 struct nfulnl_msg_packet_timestamp ts;
508 struct timeval tv = ktime_to_timeval(skb->tstamp);
509 ts.sec = cpu_to_be64(tv.tv_sec);
510 ts.usec = cpu_to_be64(tv.tv_usec);
511
512 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
513 }
514
515 /* UID */
516 if (skb->sk) {
517 read_lock_bh(&skb->sk->sk_callback_lock);
518 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
519 __be32 uid = htonl(skb->sk->sk_socket->file->f_uid);
520 /* need to unlock here since NFA_PUT may goto */
521 read_unlock_bh(&skb->sk->sk_callback_lock);
522 NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
523 } else
524 read_unlock_bh(&skb->sk->sk_callback_lock);
525 }
526
527 /* local sequence number */
528 if (inst->flags & NFULNL_CFG_F_SEQ) {
529 tmp_uint = htonl(inst->seq++);
530 NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
531 }
532 /* global sequence number */
533 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
534 tmp_uint = htonl(atomic_inc_return(&global_seq));
535 NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
536 }
537
538 if (data_len) {
539 struct nfattr *nfa;
540 int size = NFA_LENGTH(data_len);
541
542 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
543 printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
544 goto nlmsg_failure;
545 }
546
547 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
548 nfa->nfa_type = NFULA_PAYLOAD;
549 nfa->nfa_len = size;
550
551 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
552 BUG();
553 }
554
555 nlh->nlmsg_len = inst->skb->tail - old_tail;
556 inst->lastnlh = nlh;
557 return 0;
558
559 nlmsg_failure:
560 UDEBUG("nlmsg_failure\n");
561 nfattr_failure:
562 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
563 return -1;
564 }
565
566 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
567
568 static struct nf_loginfo default_loginfo = {
569 .type = NF_LOG_TYPE_ULOG,
570 .u = {
571 .ulog = {
572 .copy_len = 0xffff,
573 .group = 0,
574 .qthreshold = 1,
575 },
576 },
577 };
578
579 /* log handler for internal netfilter logging api */
580 static void
581 nfulnl_log_packet(unsigned int pf,
582 unsigned int hooknum,
583 const struct sk_buff *skb,
584 const struct net_device *in,
585 const struct net_device *out,
586 const struct nf_loginfo *li_user,
587 const char *prefix)
588 {
589 unsigned int size, data_len;
590 struct nfulnl_instance *inst;
591 const struct nf_loginfo *li;
592 unsigned int qthreshold;
593 unsigned int plen;
594
595 if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
596 li = li_user;
597 else
598 li = &default_loginfo;
599
600 inst = instance_lookup_get(li->u.ulog.group);
601 if (!inst)
602 inst = instance_lookup_get(0);
603 if (!inst) {
604 PRINTR("nfnetlink_log: trying to log packet, "
605 "but no instance for group %u\n", li->u.ulog.group);
606 return;
607 }
608
609 plen = 0;
610 if (prefix)
611 plen = strlen(prefix) + 1;
612
613 /* all macros expand to constant values at compile time */
614 /* FIXME: do we want to make the size calculation conditional based on
615 * what is actually present? way more branches and checks, but more
616 * memory efficient... */
617 size = NLMSG_SPACE(sizeof(struct nfgenmsg))
618 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
619 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
620 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
621 #ifdef CONFIG_BRIDGE_NETFILTER
622 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
623 + NFA_SPACE(sizeof(u_int32_t)) /* ifindex */
624 #endif
625 + NFA_SPACE(sizeof(u_int32_t)) /* mark */
626 + NFA_SPACE(sizeof(u_int32_t)) /* uid */
627 + NFA_SPACE(plen) /* prefix */
628 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
629 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
630
631 UDEBUG("initial size=%u\n", size);
632
633 spin_lock_bh(&inst->lock);
634
635 if (inst->flags & NFULNL_CFG_F_SEQ)
636 size += NFA_SPACE(sizeof(u_int32_t));
637 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
638 size += NFA_SPACE(sizeof(u_int32_t));
639
640 qthreshold = inst->qthreshold;
641 /* per-rule qthreshold overrides per-instance */
642 if (qthreshold > li->u.ulog.qthreshold)
643 qthreshold = li->u.ulog.qthreshold;
644
645 switch (inst->copy_mode) {
646 case NFULNL_COPY_META:
647 case NFULNL_COPY_NONE:
648 data_len = 0;
649 break;
650
651 case NFULNL_COPY_PACKET:
652 if (inst->copy_range == 0
653 || inst->copy_range > skb->len)
654 data_len = skb->len;
655 else
656 data_len = inst->copy_range;
657
658 size += NFA_SPACE(data_len);
659 UDEBUG("copy_packet, therefore size now %u\n", size);
660 break;
661
662 default:
663 spin_unlock_bh(&inst->lock);
664 instance_put(inst);
665 return;
666 }
667
668 if (!inst->skb) {
669 if (!(inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size))) {
670 UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
671 inst->nlbufsiz, size);
672 goto alloc_failure;
673 }
674 } else if (inst->qlen >= qthreshold ||
675 size > skb_tailroom(inst->skb)) {
676 /* either the queue len is too high or we don't have
677 * enough room in the skb left. flush to userspace. */
678 UDEBUG("flushing old skb\n");
679
680 /* timer "holds" one reference (we have another one) */
681 if (del_timer(&inst->timer))
682 instance_put(inst);
683 __nfulnl_send(inst);
684
685 if (!(inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size))) {
686 UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
687 inst->nlbufsiz, size);
688 goto alloc_failure;
689 }
690 }
691
692 UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
693 inst->qlen++;
694
695 __build_packet_message(inst, skb, data_len, pf,
696 hooknum, in, out, li, prefix, plen);
697
698 /* timer_pending always called within inst->lock, so there
699 * is no chance of a race here */
700 if (!timer_pending(&inst->timer)) {
701 instance_get(inst);
702 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
703 add_timer(&inst->timer);
704 }
705
706 unlock_and_release:
707 spin_unlock_bh(&inst->lock);
708 instance_put(inst);
709 return;
710
711 alloc_failure:
712 UDEBUG("error allocating skb\n");
713 /* FIXME: statistics */
714 goto unlock_and_release;
715 }
716
717 static int
718 nfulnl_rcv_nl_event(struct notifier_block *this,
719 unsigned long event, void *ptr)
720 {
721 struct netlink_notify *n = ptr;
722
723 if (event == NETLINK_URELEASE &&
724 n->protocol == NETLINK_NETFILTER && n->pid) {
725 int i;
726
727 /* destroy all instances for this pid */
728 write_lock_bh(&instances_lock);
729 for (i = 0; i < INSTANCE_BUCKETS; i++) {
730 struct hlist_node *tmp, *t2;
731 struct nfulnl_instance *inst;
732 struct hlist_head *head = &instance_table[i];
733
734 hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
735 UDEBUG("node = %p\n", inst);
736 if (n->pid == inst->peer_pid)
737 __instance_destroy(inst);
738 }
739 }
740 write_unlock_bh(&instances_lock);
741 }
742 return NOTIFY_DONE;
743 }
744
745 static struct notifier_block nfulnl_rtnl_notifier = {
746 .notifier_call = nfulnl_rcv_nl_event,
747 };
748
749 static int
750 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
751 struct nlmsghdr *nlh, struct nfattr *nfqa[])
752 {
753 return -ENOTSUPP;
754 }
755
756 static struct nf_logger nfulnl_logger = {
757 .name = "nfnetlink_log",
758 .logfn = &nfulnl_log_packet,
759 .me = THIS_MODULE,
760 };
761
762 static const int nfula_min[NFULA_MAX] = {
763 [NFULA_PACKET_HDR-1] = sizeof(struct nfulnl_msg_packet_hdr),
764 [NFULA_MARK-1] = sizeof(u_int32_t),
765 [NFULA_TIMESTAMP-1] = sizeof(struct nfulnl_msg_packet_timestamp),
766 [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
767 [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
768 [NFULA_IFINDEX_PHYSINDEV-1] = sizeof(u_int32_t),
769 [NFULA_IFINDEX_PHYSOUTDEV-1] = sizeof(u_int32_t),
770 [NFULA_HWADDR-1] = sizeof(struct nfulnl_msg_packet_hw),
771 [NFULA_PAYLOAD-1] = 0,
772 [NFULA_PREFIX-1] = 0,
773 [NFULA_UID-1] = sizeof(u_int32_t),
774 [NFULA_SEQ-1] = sizeof(u_int32_t),
775 [NFULA_SEQ_GLOBAL-1] = sizeof(u_int32_t),
776 };
777
778 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
779 [NFULA_CFG_CMD-1] = sizeof(struct nfulnl_msg_config_cmd),
780 [NFULA_CFG_MODE-1] = sizeof(struct nfulnl_msg_config_mode),
781 [NFULA_CFG_TIMEOUT-1] = sizeof(u_int32_t),
782 [NFULA_CFG_QTHRESH-1] = sizeof(u_int32_t),
783 [NFULA_CFG_NLBUFSIZ-1] = sizeof(u_int32_t),
784 [NFULA_CFG_FLAGS-1] = sizeof(u_int16_t),
785 };
786
787 static int
788 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
789 struct nlmsghdr *nlh, struct nfattr *nfula[])
790 {
791 struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
792 u_int16_t group_num = ntohs(nfmsg->res_id);
793 struct nfulnl_instance *inst;
794 int ret = 0;
795
796 UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
797
798 if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
799 UDEBUG("bad attribute size\n");
800 return -EINVAL;
801 }
802
803 inst = instance_lookup_get(group_num);
804 if (nfula[NFULA_CFG_CMD-1]) {
805 u_int8_t pf = nfmsg->nfgen_family;
806 struct nfulnl_msg_config_cmd *cmd;
807 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
808 UDEBUG("found CFG_CMD for\n");
809
810 switch (cmd->command) {
811 case NFULNL_CFG_CMD_BIND:
812 if (inst) {
813 ret = -EBUSY;
814 goto out_put;
815 }
816
817 inst = instance_create(group_num,
818 NETLINK_CB(skb).pid);
819 if (!inst) {
820 ret = -EINVAL;
821 goto out_put;
822 }
823 break;
824 case NFULNL_CFG_CMD_UNBIND:
825 if (!inst) {
826 ret = -ENODEV;
827 goto out_put;
828 }
829
830 if (inst->peer_pid != NETLINK_CB(skb).pid) {
831 ret = -EPERM;
832 goto out_put;
833 }
834
835 instance_destroy(inst);
836 break;
837 case NFULNL_CFG_CMD_PF_BIND:
838 UDEBUG("registering log handler for pf=%u\n", pf);
839 ret = nf_log_register(pf, &nfulnl_logger);
840 break;
841 case NFULNL_CFG_CMD_PF_UNBIND:
842 UDEBUG("unregistering log handler for pf=%u\n", pf);
843 /* This is a bug and a feature. We cannot unregister
844 * other handlers, like nfnetlink_inst can */
845 nf_log_unregister_pf(pf);
846 break;
847 default:
848 ret = -EINVAL;
849 break;
850 }
851
852 if (!inst)
853 goto out;
854 } else {
855 if (!inst) {
856 UDEBUG("no config command, and no instance for "
857 "group=%u pid=%u =>ENOENT\n",
858 group_num, NETLINK_CB(skb).pid);
859 ret = -ENOENT;
860 goto out_put;
861 }
862
863 if (inst->peer_pid != NETLINK_CB(skb).pid) {
864 UDEBUG("no config command, and wrong pid\n");
865 ret = -EPERM;
866 goto out_put;
867 }
868 }
869
870 if (nfula[NFULA_CFG_MODE-1]) {
871 struct nfulnl_msg_config_mode *params;
872 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
873
874 nfulnl_set_mode(inst, params->copy_mode,
875 ntohl(params->copy_range));
876 }
877
878 if (nfula[NFULA_CFG_TIMEOUT-1]) {
879 __be32 timeout =
880 *(__be32 *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
881
882 nfulnl_set_timeout(inst, ntohl(timeout));
883 }
884
885 if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
886 __be32 nlbufsiz =
887 *(__be32 *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
888
889 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
890 }
891
892 if (nfula[NFULA_CFG_QTHRESH-1]) {
893 __be32 qthresh =
894 *(__be32 *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
895
896 nfulnl_set_qthresh(inst, ntohl(qthresh));
897 }
898
899 if (nfula[NFULA_CFG_FLAGS-1]) {
900 __be16 flags =
901 *(__be16 *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
902 nfulnl_set_flags(inst, ntohs(flags));
903 }
904
905 out_put:
906 instance_put(inst);
907 out:
908 return ret;
909 }
910
911 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
912 [NFULNL_MSG_PACKET] = { .call = nfulnl_recv_unsupp,
913 .attr_count = NFULA_MAX, },
914 [NFULNL_MSG_CONFIG] = { .call = nfulnl_recv_config,
915 .attr_count = NFULA_CFG_MAX, },
916 };
917
918 static struct nfnetlink_subsystem nfulnl_subsys = {
919 .name = "log",
920 .subsys_id = NFNL_SUBSYS_ULOG,
921 .cb_count = NFULNL_MSG_MAX,
922 .cb = nfulnl_cb,
923 };
924
925 #ifdef CONFIG_PROC_FS
926 struct iter_state {
927 unsigned int bucket;
928 };
929
930 static struct hlist_node *get_first(struct seq_file *seq)
931 {
932 struct iter_state *st = seq->private;
933
934 if (!st)
935 return NULL;
936
937 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
938 if (!hlist_empty(&instance_table[st->bucket]))
939 return instance_table[st->bucket].first;
940 }
941 return NULL;
942 }
943
944 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
945 {
946 struct iter_state *st = seq->private;
947
948 h = h->next;
949 while (!h) {
950 if (++st->bucket >= INSTANCE_BUCKETS)
951 return NULL;
952
953 h = instance_table[st->bucket].first;
954 }
955 return h;
956 }
957
958 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
959 {
960 struct hlist_node *head;
961 head = get_first(seq);
962
963 if (head)
964 while (pos && (head = get_next(seq, head)))
965 pos--;
966 return pos ? NULL : head;
967 }
968
969 static void *seq_start(struct seq_file *seq, loff_t *pos)
970 {
971 read_lock_bh(&instances_lock);
972 return get_idx(seq, *pos);
973 }
974
975 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
976 {
977 (*pos)++;
978 return get_next(s, v);
979 }
980
981 static void seq_stop(struct seq_file *s, void *v)
982 {
983 read_unlock_bh(&instances_lock);
984 }
985
986 static int seq_show(struct seq_file *s, void *v)
987 {
988 const struct nfulnl_instance *inst = v;
989
990 return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
991 inst->group_num,
992 inst->peer_pid, inst->qlen,
993 inst->copy_mode, inst->copy_range,
994 inst->flushtimeout, atomic_read(&inst->use));
995 }
996
997 static struct seq_operations nful_seq_ops = {
998 .start = seq_start,
999 .next = seq_next,
1000 .stop = seq_stop,
1001 .show = seq_show,
1002 };
1003
1004 static int nful_open(struct inode *inode, struct file *file)
1005 {
1006 struct seq_file *seq;
1007 struct iter_state *is;
1008 int ret;
1009
1010 is = kzalloc(sizeof(*is), GFP_KERNEL);
1011 if (!is)
1012 return -ENOMEM;
1013 ret = seq_open(file, &nful_seq_ops);
1014 if (ret < 0)
1015 goto out_free;
1016 seq = file->private_data;
1017 seq->private = is;
1018 return ret;
1019 out_free:
1020 kfree(is);
1021 return ret;
1022 }
1023
1024 static const struct file_operations nful_file_ops = {
1025 .owner = THIS_MODULE,
1026 .open = nful_open,
1027 .read = seq_read,
1028 .llseek = seq_lseek,
1029 .release = seq_release_private,
1030 };
1031
1032 #endif /* PROC_FS */
1033
1034 static int __init nfnetlink_log_init(void)
1035 {
1036 int i, status = -ENOMEM;
1037 #ifdef CONFIG_PROC_FS
1038 struct proc_dir_entry *proc_nful;
1039 #endif
1040
1041 for (i = 0; i < INSTANCE_BUCKETS; i++)
1042 INIT_HLIST_HEAD(&instance_table[i]);
1043
1044 /* it's not really all that important to have a random value, so
1045 * we can do this from the init function, even if there hasn't
1046 * been that much entropy yet */
1047 get_random_bytes(&hash_init, sizeof(hash_init));
1048
1049 netlink_register_notifier(&nfulnl_rtnl_notifier);
1050 status = nfnetlink_subsys_register(&nfulnl_subsys);
1051 if (status < 0) {
1052 printk(KERN_ERR "log: failed to create netlink socket\n");
1053 goto cleanup_netlink_notifier;
1054 }
1055
1056 #ifdef CONFIG_PROC_FS
1057 proc_nful = create_proc_entry("nfnetlink_log", 0440,
1058 proc_net_netfilter);
1059 if (!proc_nful)
1060 goto cleanup_subsys;
1061 proc_nful->proc_fops = &nful_file_ops;
1062 #endif
1063 return status;
1064
1065 #ifdef CONFIG_PROC_FS
1066 cleanup_subsys:
1067 nfnetlink_subsys_unregister(&nfulnl_subsys);
1068 #endif
1069 cleanup_netlink_notifier:
1070 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1071 return status;
1072 }
1073
1074 static void __exit nfnetlink_log_fini(void)
1075 {
1076 nf_log_unregister(&nfulnl_logger);
1077 #ifdef CONFIG_PROC_FS
1078 remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1079 #endif
1080 nfnetlink_subsys_unregister(&nfulnl_subsys);
1081 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1082 }
1083
1084 MODULE_DESCRIPTION("netfilter userspace logging");
1085 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1086 MODULE_LICENSE("GPL");
1087 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1088
1089 module_init(nfnetlink_log_init);
1090 module_exit(nfnetlink_log_fini);
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