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