ac58dc9d72476cd335907b8230ff2680bdb18dd4
[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 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/init.h>
17 #include <linux/ip.h>
18 #include <linux/ipv6.h>
19 #include <linux/netdevice.h>
20 #include <linux/netfilter.h>
21 #include <linux/netlink.h>
22 #include <linux/netfilter/nfnetlink.h>
23 #include <linux/netfilter/nfnetlink_log.h>
24 #include <linux/spinlock.h>
25 #include <linux/sysctl.h>
26 #include <linux/proc_fs.h>
27 #include <linux/security.h>
28 #include <linux/list.h>
29 #include <linux/jhash.h>
30 #include <linux/random.h>
31 #include <net/sock.h>
32 #include <net/netfilter/nf_log.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  HZ      /* every second */
42 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
43 #define NFULNL_COPY_RANGE_MAX   0xFFFF  /* max packet size is limited by 16-bit struct nfattr nfa_len field */
44
45 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
46                                      printk(x, ## args); } while (0);
47
48 struct nfulnl_instance {
49         struct hlist_node hlist;        /* global list of instances */
50         spinlock_t lock;
51         atomic_t use;                   /* use count */
52
53         unsigned int qlen;              /* number of nlmsgs in skb */
54         struct sk_buff *skb;            /* pre-allocatd skb */
55         struct timer_list timer;
56         int peer_pid;                   /* PID of the peer process */
57
58         /* configurable parameters */
59         unsigned int flushtimeout;      /* timeout until queue flush */
60         unsigned int nlbufsiz;          /* netlink buffer allocation size */
61         unsigned int qthreshold;        /* threshold of the queue */
62         u_int32_t copy_range;
63         u_int32_t seq;                  /* instance-local sequential counter */
64         u_int16_t group_num;            /* number of this queue */
65         u_int16_t flags;
66         u_int8_t copy_mode;
67 };
68
69 static DEFINE_RWLOCK(instances_lock);
70 static atomic_t global_seq;
71
72 #define INSTANCE_BUCKETS        16
73 static struct hlist_head instance_table[INSTANCE_BUCKETS];
74 static unsigned int hash_init;
75
76 static inline u_int8_t instance_hashfn(u_int16_t group_num)
77 {
78         return ((group_num & 0xff) % INSTANCE_BUCKETS);
79 }
80
81 static struct nfulnl_instance *
82 __instance_lookup(u_int16_t group_num)
83 {
84         struct hlist_head *head;
85         struct hlist_node *pos;
86         struct nfulnl_instance *inst;
87
88         head = &instance_table[instance_hashfn(group_num)];
89         hlist_for_each_entry(inst, pos, head, hlist) {
90                 if (inst->group_num == group_num)
91                         return inst;
92         }
93         return NULL;
94 }
95
96 static inline void
97 instance_get(struct nfulnl_instance *inst)
98 {
99         atomic_inc(&inst->use);
100 }
101
102 static struct nfulnl_instance *
103 instance_lookup_get(u_int16_t group_num)
104 {
105         struct nfulnl_instance *inst;
106
107         read_lock_bh(&instances_lock);
108         inst = __instance_lookup(group_num);
109         if (inst)
110                 instance_get(inst);
111         read_unlock_bh(&instances_lock);
112
113         return inst;
114 }
115
116 static void
117 instance_put(struct nfulnl_instance *inst)
118 {
119         if (inst && atomic_dec_and_test(&inst->use)) {
120                 kfree(inst);
121                 module_put(THIS_MODULE);
122         }
123 }
124
125 static void nfulnl_timer(unsigned long data);
126
127 static struct nfulnl_instance *
128 instance_create(u_int16_t group_num, int pid)
129 {
130         struct nfulnl_instance *inst;
131         int err;
132
133         write_lock_bh(&instances_lock);
134         if (__instance_lookup(group_num)) {
135                 err = -EEXIST;
136                 goto out_unlock;
137         }
138
139         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
140         if (!inst) {
141                 err = -ENOMEM;
142                 goto out_unlock;
143         }
144
145         if (!try_module_get(THIS_MODULE)) {
146                 kfree(inst);
147                 err = -EAGAIN;
148                 goto out_unlock;
149         }
150
151         INIT_HLIST_NODE(&inst->hlist);
152         spin_lock_init(&inst->lock);
153         /* needs to be two, since we _put() after creation */
154         atomic_set(&inst->use, 2);
155
156         setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
157
158         inst->peer_pid = pid;
159         inst->group_num = group_num;
160
161         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
162         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
163         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
164         inst->copy_mode         = NFULNL_COPY_PACKET;
165         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
166
167         hlist_add_head(&inst->hlist,
168                        &instance_table[instance_hashfn(group_num)]);
169
170         write_unlock_bh(&instances_lock);
171
172         return inst;
173
174 out_unlock:
175         write_unlock_bh(&instances_lock);
176         return ERR_PTR(err);
177 }
178
179 static void __nfulnl_flush(struct nfulnl_instance *inst);
180
181 static void
182 __instance_destroy(struct nfulnl_instance *inst)
183 {
184         /* first pull it out of the global list */
185         hlist_del(&inst->hlist);
186
187         /* then flush all pending packets from skb */
188
189         spin_lock_bh(&inst->lock);
190         if (inst->skb)
191                 __nfulnl_flush(inst);
192         spin_unlock_bh(&inst->lock);
193
194         /* and finally put the refcount */
195         instance_put(inst);
196 }
197
198 static inline void
199 instance_destroy(struct nfulnl_instance *inst)
200 {
201         write_lock_bh(&instances_lock);
202         __instance_destroy(inst);
203         write_unlock_bh(&instances_lock);
204 }
205
206 static int
207 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
208                   unsigned int range)
209 {
210         int status = 0;
211
212         spin_lock_bh(&inst->lock);
213
214         switch (mode) {
215         case NFULNL_COPY_NONE:
216         case NFULNL_COPY_META:
217                 inst->copy_mode = mode;
218                 inst->copy_range = 0;
219                 break;
220
221         case NFULNL_COPY_PACKET:
222                 inst->copy_mode = mode;
223                 inst->copy_range = min_t(unsigned int,
224                                          range, NFULNL_COPY_RANGE_MAX);
225                 break;
226
227         default:
228                 status = -EINVAL;
229                 break;
230         }
231
232         spin_unlock_bh(&inst->lock);
233
234         return status;
235 }
236
237 static int
238 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
239 {
240         int status;
241
242         spin_lock_bh(&inst->lock);
243         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
244                 status = -ERANGE;
245         else if (nlbufsiz > 131072)
246                 status = -ERANGE;
247         else {
248                 inst->nlbufsiz = nlbufsiz;
249                 status = 0;
250         }
251         spin_unlock_bh(&inst->lock);
252
253         return status;
254 }
255
256 static int
257 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
258 {
259         spin_lock_bh(&inst->lock);
260         inst->flushtimeout = timeout;
261         spin_unlock_bh(&inst->lock);
262
263         return 0;
264 }
265
266 static int
267 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
268 {
269         spin_lock_bh(&inst->lock);
270         inst->qthreshold = qthresh;
271         spin_unlock_bh(&inst->lock);
272
273         return 0;
274 }
275
276 static int
277 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
278 {
279         spin_lock_bh(&inst->lock);
280         inst->flags = flags;
281         spin_unlock_bh(&inst->lock);
282
283         return 0;
284 }
285
286 static struct sk_buff *
287 nfulnl_alloc_skb(unsigned int inst_size, unsigned int pkt_size)
288 {
289         struct sk_buff *skb;
290         unsigned int n;
291
292         /* alloc skb which should be big enough for a whole multipart
293          * message.  WARNING: has to be <= 128k due to slab restrictions */
294
295         n = max(inst_size, pkt_size);
296         skb = alloc_skb(n, GFP_ATOMIC);
297         if (!skb) {
298                 PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
299                         inst_size);
300
301                 if (n > pkt_size) {
302                         /* try to allocate only as much as we need for current
303                          * packet */
304
305                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
306                         if (!skb)
307                                 PRINTR("nfnetlink_log: can't even alloc %u "
308                                        "bytes\n", pkt_size);
309                 }
310         }
311
312         return skb;
313 }
314
315 static int
316 __nfulnl_send(struct nfulnl_instance *inst)
317 {
318         int status = -1;
319
320         if (inst->qlen > 1)
321                 NLMSG_PUT(inst->skb, 0, 0,
322                           NLMSG_DONE,
323                           sizeof(struct nfgenmsg));
324
325         status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
326
327         inst->qlen = 0;
328         inst->skb = NULL;
329
330 nlmsg_failure:
331         return status;
332 }
333
334 static void
335 __nfulnl_flush(struct nfulnl_instance *inst)
336 {
337         /* timer holds a reference */
338         if (del_timer(&inst->timer))
339                 instance_put(inst);
340         if (inst->skb)
341                 __nfulnl_send(inst);
342 }
343
344 static void
345 nfulnl_timer(unsigned long data)
346 {
347         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
348
349         spin_lock_bh(&inst->lock);
350         if (inst->skb)
351                 __nfulnl_send(inst);
352         spin_unlock_bh(&inst->lock);
353         instance_put(inst);
354 }
355
356 /* This is an inline function, we don't really care about a long
357  * list of arguments */
358 static inline int
359 __build_packet_message(struct nfulnl_instance *inst,
360                         const struct sk_buff *skb,
361                         unsigned int data_len,
362                         unsigned int pf,
363                         unsigned int hooknum,
364                         const struct net_device *indev,
365                         const struct net_device *outdev,
366                         const struct nf_loginfo *li,
367                         const char *prefix, unsigned int plen)
368 {
369         struct nfulnl_msg_packet_hdr pmsg;
370         struct nlmsghdr *nlh;
371         struct nfgenmsg *nfmsg;
372         __be32 tmp_uint;
373         sk_buff_data_t old_tail = inst->skb->tail;
374
375         nlh = NLMSG_PUT(inst->skb, 0, 0,
376                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
377                         sizeof(struct nfgenmsg));
378         nfmsg = NLMSG_DATA(nlh);
379         nfmsg->nfgen_family = pf;
380         nfmsg->version = NFNETLINK_V0;
381         nfmsg->res_id = htons(inst->group_num);
382
383         pmsg.hw_protocol        = skb->protocol;
384         pmsg.hook               = hooknum;
385
386         NLA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
387
388         if (prefix)
389                 NLA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
390
391         if (indev) {
392                 tmp_uint = htonl(indev->ifindex);
393 #ifndef CONFIG_BRIDGE_NETFILTER
394                 NLA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
395                         &tmp_uint);
396 #else
397                 if (pf == PF_BRIDGE) {
398                         /* Case 1: outdev is physical input device, we need to
399                          * look for bridge group (when called from
400                          * netfilter_bridge) */
401                         NLA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
402                                 sizeof(tmp_uint), &tmp_uint);
403                         /* this is the bridge group "brX" */
404                         tmp_uint = htonl(indev->br_port->br->dev->ifindex);
405                         NLA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
406                                 sizeof(tmp_uint), &tmp_uint);
407                 } else {
408                         /* Case 2: indev is bridge group, we need to look for
409                          * physical device (when called from ipv4) */
410                         NLA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
411                                 sizeof(tmp_uint), &tmp_uint);
412                         if (skb->nf_bridge && skb->nf_bridge->physindev) {
413                                 tmp_uint =
414                                     htonl(skb->nf_bridge->physindev->ifindex);
415                                 NLA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
416                                         sizeof(tmp_uint), &tmp_uint);
417                         }
418                 }
419 #endif
420         }
421
422         if (outdev) {
423                 tmp_uint = htonl(outdev->ifindex);
424 #ifndef CONFIG_BRIDGE_NETFILTER
425                 NLA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
426                         &tmp_uint);
427 #else
428                 if (pf == PF_BRIDGE) {
429                         /* Case 1: outdev is physical output device, we need to
430                          * look for bridge group (when called from
431                          * netfilter_bridge) */
432                         NLA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
433                                 sizeof(tmp_uint), &tmp_uint);
434                         /* this is the bridge group "brX" */
435                         tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
436                         NLA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
437                                 sizeof(tmp_uint), &tmp_uint);
438                 } else {
439                         /* Case 2: indev is a bridge group, we need to look
440                          * for physical device (when called from ipv4) */
441                         NLA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
442                                 sizeof(tmp_uint), &tmp_uint);
443                         if (skb->nf_bridge && skb->nf_bridge->physoutdev) {
444                                 tmp_uint =
445                                     htonl(skb->nf_bridge->physoutdev->ifindex);
446                                 NLA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
447                                         sizeof(tmp_uint), &tmp_uint);
448                         }
449                 }
450 #endif
451         }
452
453         if (skb->mark) {
454                 tmp_uint = htonl(skb->mark);
455                 NLA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
456         }
457
458         if (indev && skb->dev) {
459                 struct nfulnl_msg_packet_hw phw;
460                 int len = dev_parse_header(skb, phw.hw_addr);
461                 if (len > 0) {
462                         phw.hw_addrlen = htons(len);
463                         NLA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
464                 }
465         }
466
467         if (skb->tstamp.tv64) {
468                 struct nfulnl_msg_packet_timestamp ts;
469                 struct timeval tv = ktime_to_timeval(skb->tstamp);
470                 ts.sec = cpu_to_be64(tv.tv_sec);
471                 ts.usec = cpu_to_be64(tv.tv_usec);
472
473                 NLA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
474         }
475
476         /* UID */
477         if (skb->sk) {
478                 read_lock_bh(&skb->sk->sk_callback_lock);
479                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
480                         __be32 uid = htonl(skb->sk->sk_socket->file->f_uid);
481                         /* need to unlock here since NLA_PUT may goto */
482                         read_unlock_bh(&skb->sk->sk_callback_lock);
483                         NLA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
484                 } else
485                         read_unlock_bh(&skb->sk->sk_callback_lock);
486         }
487
488         /* local sequence number */
489         if (inst->flags & NFULNL_CFG_F_SEQ) {
490                 tmp_uint = htonl(inst->seq++);
491                 NLA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
492         }
493         /* global sequence number */
494         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
495                 tmp_uint = htonl(atomic_inc_return(&global_seq));
496                 NLA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
497         }
498
499         if (data_len) {
500                 struct nlattr *nla;
501                 int size = nla_attr_size(data_len);
502
503                 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
504                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
505                         goto nlmsg_failure;
506                 }
507
508                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
509                 nla->nla_type = NFULA_PAYLOAD;
510                 nla->nla_len = size;
511
512                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
513                         BUG();
514         }
515
516         nlh->nlmsg_len = inst->skb->tail - old_tail;
517         return 0;
518
519 nlmsg_failure:
520 nla_put_failure:
521         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
522         return -1;
523 }
524
525 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
526
527 static struct nf_loginfo default_loginfo = {
528         .type =         NF_LOG_TYPE_ULOG,
529         .u = {
530                 .ulog = {
531                         .copy_len       = 0xffff,
532                         .group          = 0,
533                         .qthreshold     = 1,
534                 },
535         },
536 };
537
538 /* log handler for internal netfilter logging api */
539 static void
540 nfulnl_log_packet(unsigned int pf,
541                   unsigned int hooknum,
542                   const struct sk_buff *skb,
543                   const struct net_device *in,
544                   const struct net_device *out,
545                   const struct nf_loginfo *li_user,
546                   const char *prefix)
547 {
548         unsigned int size, data_len;
549         struct nfulnl_instance *inst;
550         const struct nf_loginfo *li;
551         unsigned int qthreshold;
552         unsigned int plen;
553
554         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
555                 li = li_user;
556         else
557                 li = &default_loginfo;
558
559         inst = instance_lookup_get(li->u.ulog.group);
560         if (!inst)
561                 return;
562
563         plen = 0;
564         if (prefix)
565                 plen = strlen(prefix) + 1;
566
567         /* FIXME: do we want to make the size calculation conditional based on
568          * what is actually present?  way more branches and checks, but more
569          * memory efficient... */
570         size =    NLMSG_ALIGN(sizeof(struct nfgenmsg))
571                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
572                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
573                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
574 #ifdef CONFIG_BRIDGE_NETFILTER
575                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
576                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
577 #endif
578                 + nla_total_size(sizeof(u_int32_t))     /* mark */
579                 + nla_total_size(sizeof(u_int32_t))     /* uid */
580                 + nla_total_size(plen)                  /* prefix */
581                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
582                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp));
583
584         spin_lock_bh(&inst->lock);
585
586         if (inst->flags & NFULNL_CFG_F_SEQ)
587                 size += nla_total_size(sizeof(u_int32_t));
588         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
589                 size += nla_total_size(sizeof(u_int32_t));
590
591         qthreshold = inst->qthreshold;
592         /* per-rule qthreshold overrides per-instance */
593         if (qthreshold > li->u.ulog.qthreshold)
594                 qthreshold = li->u.ulog.qthreshold;
595
596         switch (inst->copy_mode) {
597         case NFULNL_COPY_META:
598         case NFULNL_COPY_NONE:
599                 data_len = 0;
600                 break;
601
602         case NFULNL_COPY_PACKET:
603                 if (inst->copy_range == 0
604                     || inst->copy_range > skb->len)
605                         data_len = skb->len;
606                 else
607                         data_len = inst->copy_range;
608
609                 size += nla_total_size(data_len);
610                 break;
611
612         default:
613                 goto unlock_and_release;
614         }
615
616         if (inst->skb &&
617             size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) {
618                 /* either the queue len is too high or we don't have
619                  * enough room in the skb left. flush to userspace. */
620                 __nfulnl_flush(inst);
621         }
622
623         if (!inst->skb) {
624                 inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size);
625                 if (!inst->skb)
626                         goto alloc_failure;
627         }
628
629         inst->qlen++;
630
631         __build_packet_message(inst, skb, data_len, pf,
632                                 hooknum, in, out, li, prefix, plen);
633
634         if (inst->qlen >= qthreshold)
635                 __nfulnl_flush(inst);
636         /* timer_pending always called within inst->lock, so there
637          * is no chance of a race here */
638         else if (!timer_pending(&inst->timer)) {
639                 instance_get(inst);
640                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
641                 add_timer(&inst->timer);
642         }
643
644 unlock_and_release:
645         spin_unlock_bh(&inst->lock);
646         instance_put(inst);
647         return;
648
649 alloc_failure:
650         /* FIXME: statistics */
651         goto unlock_and_release;
652 }
653
654 static int
655 nfulnl_rcv_nl_event(struct notifier_block *this,
656                    unsigned long event, void *ptr)
657 {
658         struct netlink_notify *n = ptr;
659
660         if (event == NETLINK_URELEASE &&
661             n->protocol == NETLINK_NETFILTER && n->pid) {
662                 int i;
663
664                 /* destroy all instances for this pid */
665                 write_lock_bh(&instances_lock);
666                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
667                         struct hlist_node *tmp, *t2;
668                         struct nfulnl_instance *inst;
669                         struct hlist_head *head = &instance_table[i];
670
671                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
672                                 if ((n->net == &init_net) &&
673                                     (n->pid == inst->peer_pid))
674                                         __instance_destroy(inst);
675                         }
676                 }
677                 write_unlock_bh(&instances_lock);
678         }
679         return NOTIFY_DONE;
680 }
681
682 static struct notifier_block nfulnl_rtnl_notifier = {
683         .notifier_call  = nfulnl_rcv_nl_event,
684 };
685
686 static int
687 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
688                   struct nlmsghdr *nlh, struct nlattr *nfqa[])
689 {
690         return -ENOTSUPP;
691 }
692
693 static const struct nf_logger nfulnl_logger = {
694         .name   = "nfnetlink_log",
695         .logfn  = &nfulnl_log_packet,
696         .me     = THIS_MODULE,
697 };
698
699 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
700         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
701         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
702         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
703         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
704         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
705         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
706 };
707
708 static int
709 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
710                    struct nlmsghdr *nlh, struct nlattr *nfula[])
711 {
712         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
713         u_int16_t group_num = ntohs(nfmsg->res_id);
714         struct nfulnl_instance *inst;
715         int ret = 0;
716
717         inst = instance_lookup_get(group_num);
718         if (inst && inst->peer_pid != NETLINK_CB(skb).pid) {
719                 ret = -EPERM;
720                 goto out_put;
721         }
722
723         if (nfula[NFULA_CFG_CMD]) {
724                 u_int8_t pf = nfmsg->nfgen_family;
725                 struct nfulnl_msg_config_cmd *cmd;
726
727                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
728
729                 switch (cmd->command) {
730                 case NFULNL_CFG_CMD_BIND:
731                         if (inst) {
732                                 ret = -EBUSY;
733                                 goto out_put;
734                         }
735
736                         inst = instance_create(group_num,
737                                                NETLINK_CB(skb).pid);
738                         if (IS_ERR(inst)) {
739                                 ret = PTR_ERR(inst);
740                                 goto out;
741                         }
742                         break;
743                 case NFULNL_CFG_CMD_UNBIND:
744                         if (!inst) {
745                                 ret = -ENODEV;
746                                 goto out;
747                         }
748
749                         instance_destroy(inst);
750                         goto out;
751                 case NFULNL_CFG_CMD_PF_BIND:
752                         ret = nf_log_register(pf, &nfulnl_logger);
753                         break;
754                 case NFULNL_CFG_CMD_PF_UNBIND:
755                         /* This is a bug and a feature.  We cannot unregister
756                          * other handlers, like nfnetlink_inst can */
757                         nf_log_unregister_pf(pf);
758                         break;
759                 default:
760                         ret = -ENOTSUPP;
761                         break;
762                 }
763         }
764
765         if (nfula[NFULA_CFG_MODE]) {
766                 struct nfulnl_msg_config_mode *params;
767                 params = nla_data(nfula[NFULA_CFG_MODE]);
768
769                 if (!inst) {
770                         ret = -ENODEV;
771                         goto out;
772                 }
773                 nfulnl_set_mode(inst, params->copy_mode,
774                                 ntohl(params->copy_range));
775         }
776
777         if (nfula[NFULA_CFG_TIMEOUT]) {
778                 __be32 timeout =
779                         *(__be32 *)nla_data(nfula[NFULA_CFG_TIMEOUT]);
780
781                 if (!inst) {
782                         ret = -ENODEV;
783                         goto out;
784                 }
785                 nfulnl_set_timeout(inst, ntohl(timeout));
786         }
787
788         if (nfula[NFULA_CFG_NLBUFSIZ]) {
789                 __be32 nlbufsiz =
790                         *(__be32 *)nla_data(nfula[NFULA_CFG_NLBUFSIZ]);
791
792                 if (!inst) {
793                         ret = -ENODEV;
794                         goto out;
795                 }
796                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
797         }
798
799         if (nfula[NFULA_CFG_QTHRESH]) {
800                 __be32 qthresh =
801                         *(__be32 *)nla_data(nfula[NFULA_CFG_QTHRESH]);
802
803                 if (!inst) {
804                         ret = -ENODEV;
805                         goto out;
806                 }
807                 nfulnl_set_qthresh(inst, ntohl(qthresh));
808         }
809
810         if (nfula[NFULA_CFG_FLAGS]) {
811                 __be16 flags =
812                         *(__be16 *)nla_data(nfula[NFULA_CFG_FLAGS]);
813
814                 if (!inst) {
815                         ret = -ENODEV;
816                         goto out;
817                 }
818                 nfulnl_set_flags(inst, ntohs(flags));
819         }
820
821 out_put:
822         instance_put(inst);
823 out:
824         return ret;
825 }
826
827 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
828         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
829                                     .attr_count = NFULA_MAX, },
830         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
831                                     .attr_count = NFULA_CFG_MAX,
832                                     .policy = nfula_cfg_policy },
833 };
834
835 static const struct nfnetlink_subsystem nfulnl_subsys = {
836         .name           = "log",
837         .subsys_id      = NFNL_SUBSYS_ULOG,
838         .cb_count       = NFULNL_MSG_MAX,
839         .cb             = nfulnl_cb,
840 };
841
842 #ifdef CONFIG_PROC_FS
843 struct iter_state {
844         unsigned int bucket;
845 };
846
847 static struct hlist_node *get_first(struct iter_state *st)
848 {
849         if (!st)
850                 return NULL;
851
852         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
853                 if (!hlist_empty(&instance_table[st->bucket]))
854                         return instance_table[st->bucket].first;
855         }
856         return NULL;
857 }
858
859 static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
860 {
861         h = h->next;
862         while (!h) {
863                 if (++st->bucket >= INSTANCE_BUCKETS)
864                         return NULL;
865
866                 h = instance_table[st->bucket].first;
867         }
868         return h;
869 }
870
871 static struct hlist_node *get_idx(struct iter_state *st, loff_t pos)
872 {
873         struct hlist_node *head;
874         head = get_first(st);
875
876         if (head)
877                 while (pos && (head = get_next(st, head)))
878                         pos--;
879         return pos ? NULL : head;
880 }
881
882 static void *seq_start(struct seq_file *seq, loff_t *pos)
883 {
884         read_lock_bh(&instances_lock);
885         return get_idx(seq->private, *pos);
886 }
887
888 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
889 {
890         (*pos)++;
891         return get_next(s->private, v);
892 }
893
894 static void seq_stop(struct seq_file *s, void *v)
895 {
896         read_unlock_bh(&instances_lock);
897 }
898
899 static int seq_show(struct seq_file *s, void *v)
900 {
901         const struct nfulnl_instance *inst = v;
902
903         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
904                           inst->group_num,
905                           inst->peer_pid, inst->qlen,
906                           inst->copy_mode, inst->copy_range,
907                           inst->flushtimeout, atomic_read(&inst->use));
908 }
909
910 static const struct seq_operations nful_seq_ops = {
911         .start  = seq_start,
912         .next   = seq_next,
913         .stop   = seq_stop,
914         .show   = seq_show,
915 };
916
917 static int nful_open(struct inode *inode, struct file *file)
918 {
919         return seq_open_private(file, &nful_seq_ops,
920                         sizeof(struct iter_state));
921 }
922
923 static const struct file_operations nful_file_ops = {
924         .owner   = THIS_MODULE,
925         .open    = nful_open,
926         .read    = seq_read,
927         .llseek  = seq_lseek,
928         .release = seq_release_private,
929 };
930
931 #endif /* PROC_FS */
932
933 static int __init nfnetlink_log_init(void)
934 {
935         int i, status = -ENOMEM;
936 #ifdef CONFIG_PROC_FS
937         struct proc_dir_entry *proc_nful;
938 #endif
939
940         for (i = 0; i < INSTANCE_BUCKETS; i++)
941                 INIT_HLIST_HEAD(&instance_table[i]);
942
943         /* it's not really all that important to have a random value, so
944          * we can do this from the init function, even if there hasn't
945          * been that much entropy yet */
946         get_random_bytes(&hash_init, sizeof(hash_init));
947
948         netlink_register_notifier(&nfulnl_rtnl_notifier);
949         status = nfnetlink_subsys_register(&nfulnl_subsys);
950         if (status < 0) {
951                 printk(KERN_ERR "log: failed to create netlink socket\n");
952                 goto cleanup_netlink_notifier;
953         }
954
955 #ifdef CONFIG_PROC_FS
956         proc_nful = create_proc_entry("nfnetlink_log", 0440,
957                                       proc_net_netfilter);
958         if (!proc_nful)
959                 goto cleanup_subsys;
960         proc_nful->proc_fops = &nful_file_ops;
961 #endif
962         return status;
963
964 #ifdef CONFIG_PROC_FS
965 cleanup_subsys:
966         nfnetlink_subsys_unregister(&nfulnl_subsys);
967 #endif
968 cleanup_netlink_notifier:
969         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
970         return status;
971 }
972
973 static void __exit nfnetlink_log_fini(void)
974 {
975         nf_log_unregister(&nfulnl_logger);
976 #ifdef CONFIG_PROC_FS
977         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
978 #endif
979         nfnetlink_subsys_unregister(&nfulnl_subsys);
980         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
981 }
982
983 MODULE_DESCRIPTION("netfilter userspace logging");
984 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
985 MODULE_LICENSE("GPL");
986 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
987
988 module_init(nfnetlink_log_init);
989 module_exit(nfnetlink_log_fini);