[NET]: Store skb->timestamp as offset to a base timestamp
[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 4096
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 = kmalloc(sizeof(*inst), GFP_ATOMIC);
150         if (!inst)
151                 goto out_unlock;
152
153         memset(inst, 0, sizeof(*inst));
154         INIT_HLIST_NODE(&inst->hlist);
155         inst->lock = SPIN_LOCK_UNLOCKED;
156         /* needs to be two, since we _put() after creation */
157         atomic_set(&inst->use, 2);
158
159         init_timer(&inst->timer);
160         inst->timer.function = nfulnl_timer;
161         inst->timer.data = (unsigned long)inst;
162         /* don't start timer yet. (re)start it  with every packet */
163
164         inst->peer_pid = pid;
165         inst->group_num = group_num;
166
167         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
168         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
169         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
170         inst->copy_mode         = NFULNL_COPY_PACKET;
171         inst->copy_range        = 0xffff;
172
173         if (!try_module_get(THIS_MODULE))
174                 goto out_free;
175
176         hlist_add_head(&inst->hlist, 
177                        &instance_table[instance_hashfn(group_num)]);
178
179         UDEBUG("newly added node: %p, next=%p\n", &inst->hlist, 
180                 inst->hlist.next);
181
182         write_unlock_bh(&instances_lock);
183
184         return inst;
185
186 out_free:
187         instance_put(inst);
188 out_unlock:
189         write_unlock_bh(&instances_lock);
190         return NULL;
191 }
192
193 static int __nfulnl_send(struct nfulnl_instance *inst);
194
195 static void
196 _instance_destroy2(struct nfulnl_instance *inst, int lock)
197 {
198         /* first pull it out of the global list */
199         if (lock)
200                 write_lock_bh(&instances_lock);
201
202         UDEBUG("removing instance %p (queuenum=%u) from hash\n",
203                 inst, inst->group_num);
204
205         hlist_del(&inst->hlist);
206
207         if (lock)
208                 write_unlock_bh(&instances_lock);
209
210         /* then flush all pending packets from skb */
211
212         spin_lock_bh(&inst->lock);
213         if (inst->skb) {
214                 if (inst->qlen)
215                         __nfulnl_send(inst);
216                 if (inst->skb) {
217                         kfree_skb(inst->skb);
218                         inst->skb = NULL;
219                 }
220         }
221         spin_unlock_bh(&inst->lock);
222
223         /* and finally put the refcount */
224         instance_put(inst);
225
226         module_put(THIS_MODULE);
227 }
228
229 static inline void
230 __instance_destroy(struct nfulnl_instance *inst)
231 {
232         _instance_destroy2(inst, 0);
233 }
234
235 static inline void
236 instance_destroy(struct nfulnl_instance *inst)
237 {
238         _instance_destroy2(inst, 1);
239 }
240
241 static int
242 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
243                   unsigned int range)
244 {
245         int status = 0;
246
247         spin_lock_bh(&inst->lock);
248         
249         switch (mode) {
250         case NFULNL_COPY_NONE:
251         case NFULNL_COPY_META:
252                 inst->copy_mode = mode;
253                 inst->copy_range = 0;
254                 break;
255                 
256         case NFULNL_COPY_PACKET:
257                 inst->copy_mode = mode;
258                 /* we're using struct nfattr which has 16bit nfa_len */
259                 if (range > 0xffff)
260                         inst->copy_range = 0xffff;
261                 else
262                         inst->copy_range = range;
263                 break;
264                 
265         default:
266                 status = -EINVAL;
267                 break;
268         }
269
270         spin_unlock_bh(&inst->lock);
271
272         return status;
273 }
274
275 static int
276 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
277 {
278         int status;
279
280         spin_lock_bh(&inst->lock);
281         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
282                 status = -ERANGE;
283         else if (nlbufsiz > 131072)
284                 status = -ERANGE;
285         else {
286                 inst->nlbufsiz = nlbufsiz;
287                 status = 0;
288         }
289         spin_unlock_bh(&inst->lock);
290
291         return status;
292 }
293
294 static int
295 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
296 {
297         spin_lock_bh(&inst->lock);
298         inst->flushtimeout = timeout;
299         spin_unlock_bh(&inst->lock);
300
301         return 0;
302 }
303
304 static int
305 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
306 {
307         spin_lock_bh(&inst->lock);
308         inst->qthreshold = qthresh;
309         spin_unlock_bh(&inst->lock);
310
311         return 0;
312 }
313
314 static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size, 
315                                         unsigned int pkt_size)
316 {
317         struct sk_buff *skb;
318
319         UDEBUG("entered (%u, %u)\n", inst_size, pkt_size);
320
321         /* alloc skb which should be big enough for a whole multipart
322          * message.  WARNING: has to be <= 128k due to slab restrictions */
323
324         skb = alloc_skb(inst_size, GFP_ATOMIC);
325         if (!skb) {
326                 PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
327                         inst_size);
328
329                 /* try to allocate only as much as we need for current
330                  * packet */
331
332                 skb = alloc_skb(pkt_size, GFP_ATOMIC);
333                 if (!skb)
334                         PRINTR("nfnetlink_log: can't even alloc %u bytes\n",
335                                 pkt_size);
336         }
337
338         return skb;
339 }
340
341 static int
342 __nfulnl_send(struct nfulnl_instance *inst)
343 {
344         int status;
345
346         if (timer_pending(&inst->timer))
347                 del_timer(&inst->timer);
348
349         if (inst->qlen > 1)
350                 inst->lastnlh->nlmsg_type = NLMSG_DONE;
351
352         status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
353         if (status < 0) {
354                 UDEBUG("netlink_unicast() failed\n");
355                 /* FIXME: statistics */
356         }
357
358         inst->qlen = 0;
359         inst->skb = NULL;
360         inst->lastnlh = NULL;
361
362         return status;
363 }
364
365 static void nfulnl_timer(unsigned long data)
366 {
367         struct nfulnl_instance *inst = (struct nfulnl_instance *)data; 
368
369         UDEBUG("timer function called, flushing buffer\n");
370
371         spin_lock_bh(&inst->lock);
372         __nfulnl_send(inst);
373         instance_put(inst);
374         spin_unlock_bh(&inst->lock);
375 }
376
377 static inline int 
378 __build_packet_message(struct nfulnl_instance *inst,
379                         const struct sk_buff *skb, 
380                         unsigned int data_len,
381                         unsigned int pf,
382                         unsigned int hooknum,
383                         const struct net_device *indev,
384                         const struct net_device *outdev,
385                         const struct nf_loginfo *li,
386                         const char *prefix)
387 {
388         unsigned char *old_tail;
389         struct nfulnl_msg_packet_hdr pmsg;
390         struct nlmsghdr *nlh;
391         struct nfgenmsg *nfmsg;
392         u_int32_t tmp_uint;
393
394         UDEBUG("entered\n");
395                 
396         old_tail = inst->skb->tail;
397         nlh = NLMSG_PUT(inst->skb, 0, 0, 
398                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
399                         sizeof(struct nfgenmsg));
400         nfmsg = NLMSG_DATA(nlh);
401         nfmsg->nfgen_family = pf;
402         nfmsg->version = NFNETLINK_V0;
403         nfmsg->res_id = htons(inst->group_num);
404
405         pmsg.hw_protocol        = htons(skb->protocol);
406         pmsg.hook               = hooknum;
407
408         NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
409
410         if (prefix) {
411                 int slen = strlen(prefix);
412                 if (slen > NFULNL_PREFIXLEN)
413                         slen = NFULNL_PREFIXLEN;
414                 NFA_PUT(inst->skb, NFULA_PREFIX, slen, prefix);
415         }
416
417         if (indev) {
418                 tmp_uint = htonl(indev->ifindex);
419 #ifndef CONFIG_BRIDGE_NETFILTER
420                 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
421                         &tmp_uint);
422 #else
423                 if (pf == PF_BRIDGE) {
424                         /* Case 1: outdev is physical input device, we need to
425                          * look for bridge group (when called from
426                          * netfilter_bridge) */
427                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
428                                 sizeof(tmp_uint), &tmp_uint);
429                         /* this is the bridge group "brX" */
430                         tmp_uint = htonl(indev->br_port->br->dev->ifindex);
431                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
432                                 sizeof(tmp_uint), &tmp_uint);
433                 } else {
434                         /* Case 2: indev is bridge group, we need to look for
435                          * physical device (when called from ipv4) */
436                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
437                                 sizeof(tmp_uint), &tmp_uint);
438                         if (skb->nf_bridge && skb->nf_bridge->physindev) {
439                                 tmp_uint = 
440                                     htonl(skb->nf_bridge->physindev->ifindex);
441                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
442                                         sizeof(tmp_uint), &tmp_uint);
443                         }
444                 }
445 #endif
446         }
447
448         if (outdev) {
449                 tmp_uint = htonl(outdev->ifindex);
450 #ifndef CONFIG_BRIDGE_NETFILTER
451                 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
452                         &tmp_uint);
453 #else
454                 if (pf == PF_BRIDGE) {
455                         /* Case 1: outdev is physical output device, we need to
456                          * look for bridge group (when called from
457                          * netfilter_bridge) */
458                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
459                                 sizeof(tmp_uint), &tmp_uint);
460                         /* this is the bridge group "brX" */
461                         tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
462                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
463                                 sizeof(tmp_uint), &tmp_uint);
464                 } else {
465                         /* Case 2: indev is a bridge group, we need to look
466                          * for physical device (when called from ipv4) */
467                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
468                                 sizeof(tmp_uint), &tmp_uint);
469                         if (skb->nf_bridge) {
470                                 tmp_uint = 
471                                     htonl(skb->nf_bridge->physoutdev->ifindex);
472                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
473                                         sizeof(tmp_uint), &tmp_uint);
474                         }
475                 }
476 #endif
477         }
478
479         if (skb->nfmark) {
480                 tmp_uint = htonl(skb->nfmark);
481                 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
482         }
483
484         if (indev && skb->dev && skb->dev->hard_header_parse) {
485                 struct nfulnl_msg_packet_hw phw;
486
487                 phw.hw_addrlen = 
488                         skb->dev->hard_header_parse((struct sk_buff *)skb, 
489                                                     phw.hw_addr);
490                 phw.hw_addrlen = htons(phw.hw_addrlen);
491                 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
492         }
493
494         if (skb->tstamp.off_sec) {
495                 struct nfulnl_msg_packet_timestamp ts;
496
497                 ts.sec = cpu_to_be64(skb_tv_base.tv_sec + skb->tstamp.off_sec);
498                 ts.usec = cpu_to_be64(skb_tv_base.tv_usec + skb->tstamp.off_usec);
499
500                 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
501         }
502
503         /* UID */
504         if (skb->sk) {
505                 read_lock_bh(&skb->sk->sk_callback_lock);
506                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
507                         u_int32_t uid = htonl(skb->sk->sk_socket->file->f_uid);
508                         /* need to unlock here since NFA_PUT may goto */
509                         read_unlock_bh(&skb->sk->sk_callback_lock);
510                         NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
511                 } else
512                         read_unlock_bh(&skb->sk->sk_callback_lock);
513         }
514
515         if (data_len) {
516                 struct nfattr *nfa;
517                 int size = NFA_LENGTH(data_len);
518
519                 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
520                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
521                         goto nlmsg_failure;
522                 }
523
524                 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
525                 nfa->nfa_type = NFULA_PAYLOAD;
526                 nfa->nfa_len = size;
527
528                 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
529                         BUG();
530         }
531                 
532         nlh->nlmsg_len = inst->skb->tail - old_tail;
533         return 0;
534
535 nlmsg_failure:
536         UDEBUG("nlmsg_failure\n");
537 nfattr_failure:
538         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
539         return -1;
540 }
541
542 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
543
544 static struct nf_loginfo default_loginfo = {
545         .type =         NF_LOG_TYPE_ULOG,
546         .u = {
547                 .ulog = {
548                         .copy_len       = 0xffff,
549                         .group          = 0,
550                         .qthreshold     = 1,
551                 },
552         },
553 };
554
555 /* log handler for internal netfilter logging api */
556 static void
557 nfulnl_log_packet(unsigned int pf,
558                   unsigned int hooknum,
559                   const struct sk_buff *skb,
560                   const struct net_device *in,
561                   const struct net_device *out,
562                   const struct nf_loginfo *li_user,
563                   const char *prefix)
564 {
565         unsigned int size, data_len;
566         struct nfulnl_instance *inst;
567         const struct nf_loginfo *li;
568         unsigned int qthreshold;
569         unsigned int nlbufsiz;
570
571         if (li_user && li_user->type == NF_LOG_TYPE_ULOG) 
572                 li = li_user;
573         else
574                 li = &default_loginfo;
575
576         inst = instance_lookup_get(li->u.ulog.group);
577         if (!inst)
578                 inst = instance_lookup_get(0);
579         if (!inst) {
580                 PRINTR("nfnetlink_log: trying to log packet, "
581                         "but no instance for group %u\n", li->u.ulog.group);
582                 return;
583         }
584
585         /* all macros expand to constant values at compile time */
586         /* FIXME: do we want to make the size calculation conditional based on
587          * what is actually present?  way more branches and checks, but more
588          * memory efficient... */
589         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
590                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
591                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
592                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
593 #ifdef CONFIG_BRIDGE_NETFILTER
594                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
595                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
596 #endif
597                 + NFA_SPACE(sizeof(u_int32_t))  /* mark */
598                 + NFA_SPACE(sizeof(u_int32_t))  /* uid */
599                 + NFA_SPACE(NFULNL_PREFIXLEN)   /* prefix */
600                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
601                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
602
603         UDEBUG("initial size=%u\n", size);
604
605         spin_lock_bh(&inst->lock);
606
607         qthreshold = inst->qthreshold;
608         /* per-rule qthreshold overrides per-instance */
609         if (qthreshold > li->u.ulog.qthreshold)
610                 qthreshold = li->u.ulog.qthreshold;
611         
612         switch (inst->copy_mode) {
613         case NFULNL_COPY_META:
614         case NFULNL_COPY_NONE:
615                 data_len = 0;
616                 break;
617         
618         case NFULNL_COPY_PACKET:
619                 if (inst->copy_range == 0 
620                     || inst->copy_range > skb->len)
621                         data_len = skb->len;
622                 else
623                         data_len = inst->copy_range;
624                 
625                 size += NFA_SPACE(data_len);
626                 UDEBUG("copy_packet, therefore size now %u\n", size);
627                 break;
628         
629         default:
630                 spin_unlock_bh(&inst->lock);
631                 instance_put(inst);
632                 return;
633         }
634
635         if (size > inst->nlbufsiz)
636                 nlbufsiz = size;
637         else
638                 nlbufsiz = inst->nlbufsiz;
639
640         if (!inst->skb) {
641                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
642                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
643                                 inst->nlbufsiz, size);
644                         goto alloc_failure;
645                 }
646         } else if (inst->qlen >= qthreshold ||
647                    size > skb_tailroom(inst->skb)) {
648                 /* either the queue len is too high or we don't have
649                  * enough room in the skb left. flush to userspace. */
650                 UDEBUG("flushing old skb\n");
651
652                 __nfulnl_send(inst);
653
654                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
655                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
656                                 inst->nlbufsiz, size);
657                         goto alloc_failure;
658                 }
659         }
660
661         UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
662         inst->qlen++;
663
664         __build_packet_message(inst, skb, data_len, pf,
665                                 hooknum, in, out, li, prefix);
666
667         /* timer_pending always called within inst->lock, so there
668          * is no chance of a race here */
669         if (!timer_pending(&inst->timer)) {
670                 instance_get(inst);
671                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
672                 add_timer(&inst->timer);
673         }
674         spin_unlock_bh(&inst->lock);
675
676         return;
677
678 alloc_failure:
679         spin_unlock_bh(&inst->lock);
680         instance_put(inst);
681         UDEBUG("error allocating skb\n");
682         /* FIXME: statistics */
683 }
684
685 static int
686 nfulnl_rcv_nl_event(struct notifier_block *this,
687                    unsigned long event, void *ptr)
688 {
689         struct netlink_notify *n = ptr;
690
691         if (event == NETLINK_URELEASE &&
692             n->protocol == NETLINK_NETFILTER && n->pid) {
693                 int i;
694
695                 /* destroy all instances for this pid */
696                 write_lock_bh(&instances_lock);
697                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
698                         struct hlist_node *tmp, *t2;
699                         struct nfulnl_instance *inst;
700                         struct hlist_head *head = &instance_table[i];
701
702                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
703                                 UDEBUG("node = %p\n", inst);
704                                 if (n->pid == inst->peer_pid)
705                                         __instance_destroy(inst);
706                         }
707                 }
708                 write_unlock_bh(&instances_lock);
709         }
710         return NOTIFY_DONE;
711 }
712
713 static struct notifier_block nfulnl_rtnl_notifier = {
714         .notifier_call  = nfulnl_rcv_nl_event,
715 };
716
717 static int
718 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
719                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
720 {
721         return -ENOTSUPP;
722 }
723
724 static struct nf_logger nfulnl_logger = {
725         .name   = "nfnetlink_log",
726         .logfn  = &nfulnl_log_packet,
727         .me     = THIS_MODULE,
728 };
729
730 static const int nfula_min[NFULA_MAX] = {
731         [NFULA_PACKET_HDR-1]    = sizeof(struct nfulnl_msg_packet_hdr),
732         [NFULA_MARK-1]          = sizeof(u_int32_t),
733         [NFULA_TIMESTAMP-1]     = sizeof(struct nfulnl_msg_packet_timestamp),
734         [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
735         [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
736         [NFULA_HWADDR-1]        = sizeof(struct nfulnl_msg_packet_hw),
737         [NFULA_PAYLOAD-1]       = 0,
738         [NFULA_PREFIX-1]        = 0,
739         [NFULA_UID-1]           = sizeof(u_int32_t),
740 };
741
742 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
743         [NFULA_CFG_CMD-1]       = sizeof(struct nfulnl_msg_config_cmd),
744         [NFULA_CFG_MODE-1]      = sizeof(struct nfulnl_msg_config_mode),
745         [NFULA_CFG_TIMEOUT-1]   = sizeof(u_int32_t),
746         [NFULA_CFG_QTHRESH-1]   = sizeof(u_int32_t),
747         [NFULA_CFG_NLBUFSIZ-1]  = sizeof(u_int32_t),
748 };
749
750 static int
751 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
752                    struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
753 {
754         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
755         u_int16_t group_num = ntohs(nfmsg->res_id);
756         struct nfulnl_instance *inst;
757         int ret = 0;
758
759         UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
760
761         if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
762                 UDEBUG("bad attribute size\n");
763                 return -EINVAL;
764         }
765
766         inst = instance_lookup_get(group_num);
767         if (nfula[NFULA_CFG_CMD-1]) {
768                 u_int8_t pf = nfmsg->nfgen_family;
769                 struct nfulnl_msg_config_cmd *cmd;
770                 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
771                 UDEBUG("found CFG_CMD for\n");
772
773                 switch (cmd->command) {
774                 case NFULNL_CFG_CMD_BIND:
775                         if (inst) {
776                                 ret = -EBUSY;
777                                 goto out_put;
778                         }
779
780                         inst = instance_create(group_num,
781                                                NETLINK_CB(skb).pid);
782                         if (!inst) {
783                                 ret = -EINVAL;
784                                 goto out_put;
785                         }
786                         break;
787                 case NFULNL_CFG_CMD_UNBIND:
788                         if (!inst) {
789                                 ret = -ENODEV;
790                                 goto out_put;
791                         }
792
793                         if (inst->peer_pid != NETLINK_CB(skb).pid) {
794                                 ret = -EPERM;
795                                 goto out_put;
796                         }
797
798                         instance_destroy(inst);
799                         break;
800                 case NFULNL_CFG_CMD_PF_BIND:
801                         UDEBUG("registering log handler for pf=%u\n", pf);
802                         ret = nf_log_register(pf, &nfulnl_logger);
803                         break;
804                 case NFULNL_CFG_CMD_PF_UNBIND:
805                         UDEBUG("unregistering log handler for pf=%u\n", pf);
806                         /* This is a bug and a feature.  We cannot unregister
807                          * other handlers, like nfnetlink_inst can */
808                         nf_log_unregister_pf(pf);
809                         break;
810                 default:
811                         ret = -EINVAL;
812                         break;
813                 }
814         } else {
815                 if (!inst) {
816                         UDEBUG("no config command, and no instance for "
817                                 "group=%u pid=%u =>ENOENT\n",
818                                 group_num, NETLINK_CB(skb).pid);
819                         ret = -ENOENT;
820                         goto out_put;
821                 }
822
823                 if (inst->peer_pid != NETLINK_CB(skb).pid) {
824                         UDEBUG("no config command, and wrong pid\n");
825                         ret = -EPERM;
826                         goto out_put;
827                 }
828         }
829
830         if (nfula[NFULA_CFG_MODE-1]) {
831                 struct nfulnl_msg_config_mode *params;
832                 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
833
834                 nfulnl_set_mode(inst, params->copy_mode,
835                                 ntohs(params->copy_range));
836         }
837
838         if (nfula[NFULA_CFG_TIMEOUT-1]) {
839                 u_int32_t timeout = 
840                         *(u_int32_t *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
841
842                 nfulnl_set_timeout(inst, ntohl(timeout));
843         }
844
845         if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
846                 u_int32_t nlbufsiz = 
847                         *(u_int32_t *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
848
849                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
850         }
851
852         if (nfula[NFULA_CFG_QTHRESH-1]) {
853                 u_int32_t qthresh = 
854                         *(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
855
856                 nfulnl_set_qthresh(inst, ntohl(qthresh));
857         }
858
859 out_put:
860         instance_put(inst);
861         return ret;
862 }
863
864 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
865         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
866                                     .attr_count = NFULA_MAX,
867                                     .cap_required = CAP_NET_ADMIN, },
868         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
869                                     .attr_count = NFULA_CFG_MAX,
870                                     .cap_required = CAP_NET_ADMIN },
871 };
872
873 static struct nfnetlink_subsystem nfulnl_subsys = {
874         .name           = "log",
875         .subsys_id      = NFNL_SUBSYS_ULOG,
876         .cb_count       = NFULNL_MSG_MAX,
877         .cb             = nfulnl_cb,
878 };
879
880 #ifdef CONFIG_PROC_FS
881 struct iter_state {
882         unsigned int bucket;
883 };
884
885 static struct hlist_node *get_first(struct seq_file *seq)
886 {
887         struct iter_state *st = seq->private;
888
889         if (!st)
890                 return NULL;
891
892         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
893                 if (!hlist_empty(&instance_table[st->bucket]))
894                         return instance_table[st->bucket].first;
895         }
896         return NULL;
897 }
898
899 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
900 {
901         struct iter_state *st = seq->private;
902
903         h = h->next;
904         while (!h) {
905                 if (++st->bucket >= INSTANCE_BUCKETS)
906                         return NULL;
907
908                 h = instance_table[st->bucket].first;
909         }
910         return h;
911 }
912
913 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
914 {
915         struct hlist_node *head;
916         head = get_first(seq);
917
918         if (head)
919                 while (pos && (head = get_next(seq, head)))
920                         pos--;
921         return pos ? NULL : head;
922 }
923
924 static void *seq_start(struct seq_file *seq, loff_t *pos)
925 {
926         read_lock_bh(&instances_lock);
927         return get_idx(seq, *pos);
928 }
929
930 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
931 {
932         (*pos)++;
933         return get_next(s, v);
934 }
935
936 static void seq_stop(struct seq_file *s, void *v)
937 {
938         read_unlock_bh(&instances_lock);
939 }
940
941 static int seq_show(struct seq_file *s, void *v)
942 {
943         const struct nfulnl_instance *inst = v;
944
945         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n", 
946                           inst->group_num,
947                           inst->peer_pid, inst->qlen, 
948                           inst->copy_mode, inst->copy_range,
949                           inst->flushtimeout, atomic_read(&inst->use));
950 }
951
952 static struct seq_operations nful_seq_ops = {
953         .start  = seq_start,
954         .next   = seq_next,
955         .stop   = seq_stop,
956         .show   = seq_show,
957 };
958
959 static int nful_open(struct inode *inode, struct file *file)
960 {
961         struct seq_file *seq;
962         struct iter_state *is;
963         int ret;
964
965         is = kmalloc(sizeof(*is), GFP_KERNEL);
966         if (!is)
967                 return -ENOMEM;
968         memset(is, 0, sizeof(*is));
969         ret = seq_open(file, &nful_seq_ops);
970         if (ret < 0)
971                 goto out_free;
972         seq = file->private_data;
973         seq->private = is;
974         return ret;
975 out_free:
976         kfree(is);
977         return ret;
978 }
979
980 static struct file_operations nful_file_ops = {
981         .owner   = THIS_MODULE,
982         .open    = nful_open,
983         .read    = seq_read,
984         .llseek  = seq_lseek,
985         .release = seq_release_private,
986 };
987
988 #endif /* PROC_FS */
989
990 static int
991 init_or_cleanup(int init)
992 {
993         int i, status = -ENOMEM;
994 #ifdef CONFIG_PROC_FS
995         struct proc_dir_entry *proc_nful;
996 #endif
997         
998         if (!init)
999                 goto cleanup;
1000
1001         for (i = 0; i < INSTANCE_BUCKETS; i++)
1002                 INIT_HLIST_HEAD(&instance_table[i]);
1003         
1004         /* it's not really all that important to have a random value, so
1005          * we can do this from the init function, even if there hasn't
1006          * been that much entropy yet */
1007         get_random_bytes(&hash_init, sizeof(hash_init));
1008
1009         netlink_register_notifier(&nfulnl_rtnl_notifier);
1010         status = nfnetlink_subsys_register(&nfulnl_subsys);
1011         if (status < 0) {
1012                 printk(KERN_ERR "log: failed to create netlink socket\n");
1013                 goto cleanup_netlink_notifier;
1014         }
1015
1016 #ifdef CONFIG_PROC_FS
1017         proc_nful = create_proc_entry("nfnetlink_log", 0440,
1018                                       proc_net_netfilter);
1019         if (!proc_nful)
1020                 goto cleanup_subsys;
1021         proc_nful->proc_fops = &nful_file_ops;
1022 #endif
1023
1024         return status;
1025
1026 cleanup:
1027         nf_log_unregister_logger(&nfulnl_logger);
1028 #ifdef CONFIG_PROC_FS
1029         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1030 cleanup_subsys:
1031 #endif
1032         nfnetlink_subsys_unregister(&nfulnl_subsys);
1033 cleanup_netlink_notifier:
1034         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1035         return status;
1036 }
1037
1038 static int __init init(void)
1039 {
1040         
1041         return init_or_cleanup(1);
1042 }
1043
1044 static void __exit fini(void)
1045 {
1046         init_or_cleanup(0);
1047 }
1048
1049 MODULE_DESCRIPTION("netfilter userspace logging");
1050 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1051 MODULE_LICENSE("GPL");
1052 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1053
1054 module_init(init);
1055 module_exit(fini);