[NETFILTER]: nfnetlink_log: fix module reference counting
[linux-2.6.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);