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TOMOYO Linux Cross Reference
Linux/net/netfilter/nfnetlink_log.c

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  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/if_arp.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 <linux/slab.h>
 33 #include <net/sock.h>
 34 #include <net/netfilter/nf_log.h>
 35 #include <net/netfilter/nfnetlink_log.h>
 36 
 37 #include <linux/atomic.h>
 38 
 39 #ifdef CONFIG_BRIDGE_NETFILTER
 40 #include "../bridge/br_private.h"
 41 #endif
 42 
 43 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
 44 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
 45 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
 46 #define NFULNL_COPY_RANGE_MAX   0xFFFF  /* max packet size is limited by 16-bit struct nfattr nfa_len field */
 47 
 48 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
 49                                      printk(x, ## args); } while (0);
 50 
 51 struct nfulnl_instance {
 52         struct hlist_node hlist;        /* global list of instances */
 53         spinlock_t lock;
 54         atomic_t use;                   /* use count */
 55 
 56         unsigned int qlen;              /* number of nlmsgs in skb */
 57         struct sk_buff *skb;            /* pre-allocatd skb */
 58         struct timer_list timer;
 59         struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
 60         int peer_portid;                        /* PORTID of the peer process */
 61 
 62         /* configurable parameters */
 63         unsigned int flushtimeout;      /* timeout until queue flush */
 64         unsigned int nlbufsiz;          /* netlink buffer allocation size */
 65         unsigned int qthreshold;        /* threshold of the queue */
 66         u_int32_t copy_range;
 67         u_int32_t seq;                  /* instance-local sequential counter */
 68         u_int16_t group_num;            /* number of this queue */
 69         u_int16_t flags;
 70         u_int8_t copy_mode;
 71         struct rcu_head rcu;
 72 };
 73 
 74 static DEFINE_SPINLOCK(instances_lock);
 75 static atomic_t global_seq;
 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 nfulnl_instance *inst;
 91 
 92         head = &instance_table[instance_hashfn(group_num)];
 93         hlist_for_each_entry_rcu(inst, head, hlist) {
 94                 if (inst->group_num == group_num)
 95                         return inst;
 96         }
 97         return NULL;
 98 }
 99 
100 static inline void
101 instance_get(struct nfulnl_instance *inst)
102 {
103         atomic_inc(&inst->use);
104 }
105 
106 static struct nfulnl_instance *
107 instance_lookup_get(u_int16_t group_num)
108 {
109         struct nfulnl_instance *inst;
110 
111         rcu_read_lock_bh();
112         inst = __instance_lookup(group_num);
113         if (inst && !atomic_inc_not_zero(&inst->use))
114                 inst = NULL;
115         rcu_read_unlock_bh();
116 
117         return inst;
118 }
119 
120 static void nfulnl_instance_free_rcu(struct rcu_head *head)
121 {
122         kfree(container_of(head, struct nfulnl_instance, rcu));
123         module_put(THIS_MODULE);
124 }
125 
126 static void
127 instance_put(struct nfulnl_instance *inst)
128 {
129         if (inst && atomic_dec_and_test(&inst->use))
130                 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
131 }
132 
133 static void nfulnl_timer(unsigned long data);
134 
135 static struct nfulnl_instance *
136 instance_create(u_int16_t group_num, int portid, struct user_namespace *user_ns)
137 {
138         struct nfulnl_instance *inst;
139         int err;
140 
141         spin_lock_bh(&instances_lock);
142         if (__instance_lookup(group_num)) {
143                 err = -EEXIST;
144                 goto out_unlock;
145         }
146 
147         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
148         if (!inst) {
149                 err = -ENOMEM;
150                 goto out_unlock;
151         }
152 
153         if (!try_module_get(THIS_MODULE)) {
154                 kfree(inst);
155                 err = -EAGAIN;
156                 goto out_unlock;
157         }
158 
159         INIT_HLIST_NODE(&inst->hlist);
160         spin_lock_init(&inst->lock);
161         /* needs to be two, since we _put() after creation */
162         atomic_set(&inst->use, 2);
163 
164         setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
165 
166         inst->peer_user_ns = user_ns;
167         inst->peer_portid = portid;
168         inst->group_num = group_num;
169 
170         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
171         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
172         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
173         inst->copy_mode         = NFULNL_COPY_PACKET;
174         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
175 
176         hlist_add_head_rcu(&inst->hlist,
177                        &instance_table[instance_hashfn(group_num)]);
178 
179         spin_unlock_bh(&instances_lock);
180 
181         return inst;
182 
183 out_unlock:
184         spin_unlock_bh(&instances_lock);
185         return ERR_PTR(err);
186 }
187 
188 static void __nfulnl_flush(struct nfulnl_instance *inst);
189 
190 /* called with BH disabled */
191 static void
192 __instance_destroy(struct nfulnl_instance *inst)
193 {
194         /* first pull it out of the global list */
195         hlist_del_rcu(&inst->hlist);
196 
197         /* then flush all pending packets from skb */
198 
199         spin_lock(&inst->lock);
200 
201         /* lockless readers wont be able to use us */
202         inst->copy_mode = NFULNL_COPY_DISABLED;
203 
204         if (inst->skb)
205                 __nfulnl_flush(inst);
206         spin_unlock(&inst->lock);
207 
208         /* and finally put the refcount */
209         instance_put(inst);
210 }
211 
212 static inline void
213 instance_destroy(struct nfulnl_instance *inst)
214 {
215         spin_lock_bh(&instances_lock);
216         __instance_destroy(inst);
217         spin_unlock_bh(&instances_lock);
218 }
219 
220 static int
221 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
222                   unsigned int range)
223 {
224         int status = 0;
225 
226         spin_lock_bh(&inst->lock);
227 
228         switch (mode) {
229         case NFULNL_COPY_NONE:
230         case NFULNL_COPY_META:
231                 inst->copy_mode = mode;
232                 inst->copy_range = 0;
233                 break;
234 
235         case NFULNL_COPY_PACKET:
236                 inst->copy_mode = mode;
237                 inst->copy_range = min_t(unsigned int,
238                                          range, NFULNL_COPY_RANGE_MAX);
239                 break;
240 
241         default:
242                 status = -EINVAL;
243                 break;
244         }
245 
246         spin_unlock_bh(&inst->lock);
247 
248         return status;
249 }
250 
251 static int
252 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
253 {
254         int status;
255 
256         spin_lock_bh(&inst->lock);
257         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
258                 status = -ERANGE;
259         else if (nlbufsiz > 131072)
260                 status = -ERANGE;
261         else {
262                 inst->nlbufsiz = nlbufsiz;
263                 status = 0;
264         }
265         spin_unlock_bh(&inst->lock);
266 
267         return status;
268 }
269 
270 static int
271 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
272 {
273         spin_lock_bh(&inst->lock);
274         inst->flushtimeout = timeout;
275         spin_unlock_bh(&inst->lock);
276 
277         return 0;
278 }
279 
280 static int
281 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
282 {
283         spin_lock_bh(&inst->lock);
284         inst->qthreshold = qthresh;
285         spin_unlock_bh(&inst->lock);
286 
287         return 0;
288 }
289 
290 static int
291 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
292 {
293         spin_lock_bh(&inst->lock);
294         inst->flags = flags;
295         spin_unlock_bh(&inst->lock);
296 
297         return 0;
298 }
299 
300 static struct sk_buff *
301 nfulnl_alloc_skb(unsigned int inst_size, unsigned int pkt_size)
302 {
303         struct sk_buff *skb;
304         unsigned int n;
305 
306         /* alloc skb which should be big enough for a whole multipart
307          * message.  WARNING: has to be <= 128k due to slab restrictions */
308 
309         n = max(inst_size, pkt_size);
310         skb = alloc_skb(n, GFP_ATOMIC);
311         if (!skb) {
312                 if (n > pkt_size) {
313                         /* try to allocate only as much as we need for current
314                          * packet */
315 
316                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
317                         if (!skb)
318                                 pr_err("nfnetlink_log: can't even alloc %u bytes\n",
319                                        pkt_size);
320                 }
321         }
322 
323         return skb;
324 }
325 
326 static int
327 __nfulnl_send(struct nfulnl_instance *inst)
328 {
329         int status = -1;
330 
331         if (inst->qlen > 1) {
332                 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
333                                                  NLMSG_DONE,
334                                                  sizeof(struct nfgenmsg),
335                                                  0);
336                 if (!nlh)
337                         goto out;
338         }
339         status = nfnetlink_unicast(inst->skb, &init_net, inst->peer_portid,
340                                    MSG_DONTWAIT);
341 
342         inst->qlen = 0;
343         inst->skb = NULL;
344 out:
345         return status;
346 }
347 
348 static void
349 __nfulnl_flush(struct nfulnl_instance *inst)
350 {
351         /* timer holds a reference */
352         if (del_timer(&inst->timer))
353                 instance_put(inst);
354         if (inst->skb)
355                 __nfulnl_send(inst);
356 }
357 
358 static void
359 nfulnl_timer(unsigned long data)
360 {
361         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
362 
363         spin_lock_bh(&inst->lock);
364         if (inst->skb)
365                 __nfulnl_send(inst);
366         spin_unlock_bh(&inst->lock);
367         instance_put(inst);
368 }
369 
370 /* This is an inline function, we don't really care about a long
371  * list of arguments */
372 static inline int
373 __build_packet_message(struct nfulnl_instance *inst,
374                         const struct sk_buff *skb,
375                         unsigned int data_len,
376                         u_int8_t pf,
377                         unsigned int hooknum,
378                         const struct net_device *indev,
379                         const struct net_device *outdev,
380                         const char *prefix, unsigned int plen)
381 {
382         struct nfulnl_msg_packet_hdr pmsg;
383         struct nlmsghdr *nlh;
384         struct nfgenmsg *nfmsg;
385         sk_buff_data_t old_tail = inst->skb->tail;
386         struct sock *sk;
387         const unsigned char *hwhdrp;
388 
389         nlh = nlmsg_put(inst->skb, 0, 0,
390                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
391                         sizeof(struct nfgenmsg), 0);
392         if (!nlh)
393                 return -1;
394         nfmsg = nlmsg_data(nlh);
395         nfmsg->nfgen_family = pf;
396         nfmsg->version = NFNETLINK_V0;
397         nfmsg->res_id = htons(inst->group_num);
398 
399         pmsg.hw_protocol        = skb->protocol;
400         pmsg.hook               = hooknum;
401 
402         if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
403                 goto nla_put_failure;
404 
405         if (prefix &&
406             nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
407                 goto nla_put_failure;
408 
409         if (indev) {
410 #ifndef CONFIG_BRIDGE_NETFILTER
411                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
412                                  htonl(indev->ifindex)))
413                         goto nla_put_failure;
414 #else
415                 if (pf == PF_BRIDGE) {
416                         /* Case 1: outdev is physical input device, we need to
417                          * look for bridge group (when called from
418                          * netfilter_bridge) */
419                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
420                                          htonl(indev->ifindex)) ||
421                         /* this is the bridge group "brX" */
422                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
423                             nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
424                                          htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
425                                 goto nla_put_failure;
426                 } else {
427                         /* Case 2: indev is bridge group, we need to look for
428                          * physical device (when called from ipv4) */
429                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
430                                          htonl(indev->ifindex)))
431                                 goto nla_put_failure;
432                         if (skb->nf_bridge && skb->nf_bridge->physindev &&
433                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
434                                          htonl(skb->nf_bridge->physindev->ifindex)))
435                                 goto nla_put_failure;
436                 }
437 #endif
438         }
439 
440         if (outdev) {
441 #ifndef CONFIG_BRIDGE_NETFILTER
442                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
443                                  htonl(outdev->ifindex)))
444                         goto nla_put_failure;
445 #else
446                 if (pf == PF_BRIDGE) {
447                         /* Case 1: outdev is physical output device, we need to
448                          * look for bridge group (when called from
449                          * netfilter_bridge) */
450                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
451                                          htonl(outdev->ifindex)) ||
452                         /* this is the bridge group "brX" */
453                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
454                             nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
455                                          htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
456                                 goto nla_put_failure;
457                 } else {
458                         /* Case 2: indev is a bridge group, we need to look
459                          * for physical device (when called from ipv4) */
460                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
461                                          htonl(outdev->ifindex)))
462                                 goto nla_put_failure;
463                         if (skb->nf_bridge && skb->nf_bridge->physoutdev &&
464                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
465                                          htonl(skb->nf_bridge->physoutdev->ifindex)))
466                                 goto nla_put_failure;
467                 }
468 #endif
469         }
470 
471         if (skb->mark &&
472             nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
473                 goto nla_put_failure;
474 
475         if (indev && skb->dev &&
476             skb->mac_header != skb->network_header) {
477                 struct nfulnl_msg_packet_hw phw;
478                 int len = dev_parse_header(skb, phw.hw_addr);
479                 if (len > 0) {
480                         phw.hw_addrlen = htons(len);
481                         if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
482                                 goto nla_put_failure;
483                 }
484         }
485 
486         if (indev && skb_mac_header_was_set(skb)) {
487                 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
488                     nla_put_be16(inst->skb, NFULA_HWLEN,
489                                  htons(skb->dev->hard_header_len)))
490                         goto nla_put_failure;
491 
492                 hwhdrp = skb_mac_header(skb);
493 
494                 if (skb->dev->type == ARPHRD_SIT)
495                         hwhdrp -= ETH_HLEN;
496 
497                 if (hwhdrp >= skb->head &&
498                     nla_put(inst->skb, NFULA_HWHEADER,
499                             skb->dev->hard_header_len, hwhdrp))
500                         goto nla_put_failure;
501         }
502 
503         if (skb->tstamp.tv64) {
504                 struct nfulnl_msg_packet_timestamp ts;
505                 struct timeval tv = ktime_to_timeval(skb->tstamp);
506                 ts.sec = cpu_to_be64(tv.tv_sec);
507                 ts.usec = cpu_to_be64(tv.tv_usec);
508 
509                 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
510                         goto nla_put_failure;
511         }
512 
513         /* UID */
514         sk = skb->sk;
515         if (sk && sk->sk_state != TCP_TIME_WAIT) {
516                 read_lock_bh(&sk->sk_callback_lock);
517                 if (sk->sk_socket && sk->sk_socket->file) {
518                         struct file *file = sk->sk_socket->file;
519                         const struct cred *cred = file->f_cred;
520                         struct user_namespace *user_ns = inst->peer_user_ns;
521                         __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
522                         __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
523                         read_unlock_bh(&sk->sk_callback_lock);
524                         if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
525                             nla_put_be32(inst->skb, NFULA_GID, gid))
526                                 goto nla_put_failure;
527                 } else
528                         read_unlock_bh(&sk->sk_callback_lock);
529         }
530 
531         /* local sequence number */
532         if ((inst->flags & NFULNL_CFG_F_SEQ) &&
533             nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
534                 goto nla_put_failure;
535 
536         /* global sequence number */
537         if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
538             nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
539                          htonl(atomic_inc_return(&global_seq))))
540                 goto nla_put_failure;
541 
542         if (data_len) {
543                 struct nlattr *nla;
544                 int size = nla_attr_size(data_len);
545 
546                 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
547                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
548                         return -1;
549                 }
550 
551                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
552                 nla->nla_type = NFULA_PAYLOAD;
553                 nla->nla_len = size;
554 
555                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
556                         BUG();
557         }
558 
559         nlh->nlmsg_len = inst->skb->tail - old_tail;
560         return 0;
561 
562 nla_put_failure:
563         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
564         return -1;
565 }
566 
567 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
568 
569 static struct nf_loginfo default_loginfo = {
570         .type =         NF_LOG_TYPE_ULOG,
571         .u = {
572                 .ulog = {
573                         .copy_len       = 0xffff,
574                         .group          = 0,
575                         .qthreshold     = 1,
576                 },
577         },
578 };
579 
580 /* log handler for internal netfilter logging api */
581 void
582 nfulnl_log_packet(u_int8_t pf,
583                   unsigned int hooknum,
584                   const struct sk_buff *skb,
585                   const struct net_device *in,
586                   const struct net_device *out,
587                   const struct nf_loginfo *li_user,
588                   const char *prefix)
589 {
590         unsigned int size, data_len;
591         struct nfulnl_instance *inst;
592         const struct nf_loginfo *li;
593         unsigned int qthreshold;
594         unsigned int plen;
595 
596         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
597                 li = li_user;
598         else
599                 li = &default_loginfo;
600 
601         inst = instance_lookup_get(li->u.ulog.group);
602         if (!inst)
603                 return;
604 
605         plen = 0;
606         if (prefix)
607                 plen = strlen(prefix) + 1;
608 
609         /* FIXME: do we want to make the size calculation conditional based on
610          * what is actually present?  way more branches and checks, but more
611          * memory efficient... */
612         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
613                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
614                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
615                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
616 #ifdef CONFIG_BRIDGE_NETFILTER
617                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
618                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
619 #endif
620                 + nla_total_size(sizeof(u_int32_t))     /* mark */
621                 + nla_total_size(sizeof(u_int32_t))     /* uid */
622                 + nla_total_size(sizeof(u_int32_t))     /* gid */
623                 + nla_total_size(plen)                  /* prefix */
624                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
625                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp));
626 
627         if (in && skb_mac_header_was_set(skb)) {
628                 size +=   nla_total_size(skb->dev->hard_header_len)
629                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
630                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
631         }
632 
633         spin_lock_bh(&inst->lock);
634 
635         if (inst->flags & NFULNL_CFG_F_SEQ)
636                 size += nla_total_size(sizeof(u_int32_t));
637         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
638                 size += nla_total_size(sizeof(u_int32_t));
639 
640         qthreshold = inst->qthreshold;
641         /* per-rule qthreshold overrides per-instance */
642         if (li->u.ulog.qthreshold)
643                 if (qthreshold > li->u.ulog.qthreshold)
644                         qthreshold = li->u.ulog.qthreshold;
645 
646 
647         switch (inst->copy_mode) {
648         case NFULNL_COPY_META:
649         case NFULNL_COPY_NONE:
650                 data_len = 0;
651                 break;
652 
653         case NFULNL_COPY_PACKET:
654                 if (inst->copy_range == 0
655                     || inst->copy_range > skb->len)
656                         data_len = skb->len;
657                 else
658                         data_len = inst->copy_range;
659 
660                 size += nla_total_size(data_len);
661                 break;
662 
663         case NFULNL_COPY_DISABLED:
664         default:
665                 goto unlock_and_release;
666         }
667 
668         if (inst->skb &&
669             size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) {
670                 /* either the queue len is too high or we don't have
671                  * enough room in the skb left. flush to userspace. */
672                 __nfulnl_flush(inst);
673         }
674 
675         if (!inst->skb) {
676                 inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size);
677                 if (!inst->skb)
678                         goto alloc_failure;
679         }
680 
681         inst->qlen++;
682 
683         __build_packet_message(inst, skb, data_len, pf,
684                                 hooknum, in, out, prefix, plen);
685 
686         if (inst->qlen >= qthreshold)
687                 __nfulnl_flush(inst);
688         /* timer_pending always called within inst->lock, so there
689          * is no chance of a race here */
690         else if (!timer_pending(&inst->timer)) {
691                 instance_get(inst);
692                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
693                 add_timer(&inst->timer);
694         }
695 
696 unlock_and_release:
697         spin_unlock_bh(&inst->lock);
698         instance_put(inst);
699         return;
700 
701 alloc_failure:
702         /* FIXME: statistics */
703         goto unlock_and_release;
704 }
705 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
706 
707 static int
708 nfulnl_rcv_nl_event(struct notifier_block *this,
709                    unsigned long event, void *ptr)
710 {
711         struct netlink_notify *n = ptr;
712 
713         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
714                 int i;
715 
716                 /* destroy all instances for this portid */
717                 spin_lock_bh(&instances_lock);
718                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
719                         struct hlist_node *t2;
720                         struct nfulnl_instance *inst;
721                         struct hlist_head *head = &instance_table[i];
722 
723                         hlist_for_each_entry_safe(inst, t2, head, hlist) {
724                                 if ((net_eq(n->net, &init_net)) &&
725                                     (n->portid == inst->peer_portid))
726                                         __instance_destroy(inst);
727                         }
728                 }
729                 spin_unlock_bh(&instances_lock);
730         }
731         return NOTIFY_DONE;
732 }
733 
734 static struct notifier_block nfulnl_rtnl_notifier = {
735         .notifier_call  = nfulnl_rcv_nl_event,
736 };
737 
738 static int
739 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
740                    const struct nlmsghdr *nlh,
741                    const struct nlattr * const nfqa[])
742 {
743         return -ENOTSUPP;
744 }
745 
746 static struct nf_logger nfulnl_logger __read_mostly = {
747         .name   = "nfnetlink_log",
748         .logfn  = &nfulnl_log_packet,
749         .me     = THIS_MODULE,
750 };
751 
752 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
753         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
754         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
755         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
756         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
757         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
758         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
759 };
760 
761 static int
762 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
763                    const struct nlmsghdr *nlh,
764                    const struct nlattr * const nfula[])
765 {
766         struct nfgenmsg *nfmsg = nlmsg_data(nlh);
767         u_int16_t group_num = ntohs(nfmsg->res_id);
768         struct nfulnl_instance *inst;
769         struct nfulnl_msg_config_cmd *cmd = NULL;
770         int ret = 0;
771 
772         if (nfula[NFULA_CFG_CMD]) {
773                 u_int8_t pf = nfmsg->nfgen_family;
774                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
775 
776                 /* Commands without queue context */
777                 switch (cmd->command) {
778                 case NFULNL_CFG_CMD_PF_BIND:
779                         return nf_log_bind_pf(pf, &nfulnl_logger);
780                 case NFULNL_CFG_CMD_PF_UNBIND:
781                         nf_log_unbind_pf(pf);
782                         return 0;
783                 }
784         }
785 
786         inst = instance_lookup_get(group_num);
787         if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
788                 ret = -EPERM;
789                 goto out_put;
790         }
791 
792         if (cmd != NULL) {
793                 switch (cmd->command) {
794                 case NFULNL_CFG_CMD_BIND:
795                         if (inst) {
796                                 ret = -EBUSY;
797                                 goto out_put;
798                         }
799 
800                         inst = instance_create(group_num,
801                                                NETLINK_CB(skb).portid,
802                                                sk_user_ns(NETLINK_CB(skb).ssk));
803                         if (IS_ERR(inst)) {
804                                 ret = PTR_ERR(inst);
805                                 goto out;
806                         }
807                         break;
808                 case NFULNL_CFG_CMD_UNBIND:
809                         if (!inst) {
810                                 ret = -ENODEV;
811                                 goto out;
812                         }
813 
814                         instance_destroy(inst);
815                         goto out_put;
816                 default:
817                         ret = -ENOTSUPP;
818                         break;
819                 }
820         }
821 
822         if (nfula[NFULA_CFG_MODE]) {
823                 struct nfulnl_msg_config_mode *params;
824                 params = nla_data(nfula[NFULA_CFG_MODE]);
825 
826                 if (!inst) {
827                         ret = -ENODEV;
828                         goto out;
829                 }
830                 nfulnl_set_mode(inst, params->copy_mode,
831                                 ntohl(params->copy_range));
832         }
833 
834         if (nfula[NFULA_CFG_TIMEOUT]) {
835                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
836 
837                 if (!inst) {
838                         ret = -ENODEV;
839                         goto out;
840                 }
841                 nfulnl_set_timeout(inst, ntohl(timeout));
842         }
843 
844         if (nfula[NFULA_CFG_NLBUFSIZ]) {
845                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
846 
847                 if (!inst) {
848                         ret = -ENODEV;
849                         goto out;
850                 }
851                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
852         }
853 
854         if (nfula[NFULA_CFG_QTHRESH]) {
855                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
856 
857                 if (!inst) {
858                         ret = -ENODEV;
859                         goto out;
860                 }
861                 nfulnl_set_qthresh(inst, ntohl(qthresh));
862         }
863 
864         if (nfula[NFULA_CFG_FLAGS]) {
865                 __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
866 
867                 if (!inst) {
868                         ret = -ENODEV;
869                         goto out;
870                 }
871                 nfulnl_set_flags(inst, ntohs(flags));
872         }
873 
874 out_put:
875         instance_put(inst);
876 out:
877         return ret;
878 }
879 
880 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
881         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
882                                     .attr_count = NFULA_MAX, },
883         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
884                                     .attr_count = NFULA_CFG_MAX,
885                                     .policy = nfula_cfg_policy },
886 };
887 
888 static const struct nfnetlink_subsystem nfulnl_subsys = {
889         .name           = "log",
890         .subsys_id      = NFNL_SUBSYS_ULOG,
891         .cb_count       = NFULNL_MSG_MAX,
892         .cb             = nfulnl_cb,
893 };
894 
895 #ifdef CONFIG_PROC_FS
896 struct iter_state {
897         unsigned int bucket;
898 };
899 
900 static struct hlist_node *get_first(struct iter_state *st)
901 {
902         if (!st)
903                 return NULL;
904 
905         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
906                 if (!hlist_empty(&instance_table[st->bucket]))
907                         return rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
908         }
909         return NULL;
910 }
911 
912 static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
913 {
914         h = rcu_dereference_bh(hlist_next_rcu(h));
915         while (!h) {
916                 if (++st->bucket >= INSTANCE_BUCKETS)
917                         return NULL;
918 
919                 h = rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
920         }
921         return h;
922 }
923 
924 static struct hlist_node *get_idx(struct iter_state *st, loff_t pos)
925 {
926         struct hlist_node *head;
927         head = get_first(st);
928 
929         if (head)
930                 while (pos && (head = get_next(st, head)))
931                         pos--;
932         return pos ? NULL : head;
933 }
934 
935 static void *seq_start(struct seq_file *seq, loff_t *pos)
936         __acquires(rcu_bh)
937 {
938         rcu_read_lock_bh();
939         return get_idx(seq->private, *pos);
940 }
941 
942 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
943 {
944         (*pos)++;
945         return get_next(s->private, v);
946 }
947 
948 static void seq_stop(struct seq_file *s, void *v)
949         __releases(rcu_bh)
950 {
951         rcu_read_unlock_bh();
952 }
953 
954 static int seq_show(struct seq_file *s, void *v)
955 {
956         const struct nfulnl_instance *inst = v;
957 
958         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
959                           inst->group_num,
960                           inst->peer_portid, inst->qlen,
961                           inst->copy_mode, inst->copy_range,
962                           inst->flushtimeout, atomic_read(&inst->use));
963 }
964 
965 static const struct seq_operations nful_seq_ops = {
966         .start  = seq_start,
967         .next   = seq_next,
968         .stop   = seq_stop,
969         .show   = seq_show,
970 };
971 
972 static int nful_open(struct inode *inode, struct file *file)
973 {
974         return seq_open_private(file, &nful_seq_ops,
975                         sizeof(struct iter_state));
976 }
977 
978 static const struct file_operations nful_file_ops = {
979         .owner   = THIS_MODULE,
980         .open    = nful_open,
981         .read    = seq_read,
982         .llseek  = seq_lseek,
983         .release = seq_release_private,
984 };
985 
986 #endif /* PROC_FS */
987 
988 static int __init nfnetlink_log_init(void)
989 {
990         int i, status = -ENOMEM;
991 
992         for (i = 0; i < INSTANCE_BUCKETS; i++)
993                 INIT_HLIST_HEAD(&instance_table[i]);
994 
995         /* it's not really all that important to have a random value, so
996          * we can do this from the init function, even if there hasn't
997          * been that much entropy yet */
998         get_random_bytes(&hash_init, sizeof(hash_init));
999 
1000         netlink_register_notifier(&nfulnl_rtnl_notifier);
1001         status = nfnetlink_subsys_register(&nfulnl_subsys);
1002         if (status < 0) {
1003                 printk(KERN_ERR "log: failed to create netlink socket\n");
1004                 goto cleanup_netlink_notifier;
1005         }
1006 
1007         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1008         if (status < 0) {
1009                 printk(KERN_ERR "log: failed to register logger\n");
1010                 goto cleanup_subsys;
1011         }
1012 
1013 #ifdef CONFIG_PROC_FS
1014         if (!proc_create("nfnetlink_log", 0440,
1015                          proc_net_netfilter, &nful_file_ops)) {
1016                 status = -ENOMEM;
1017                 goto cleanup_logger;
1018         }
1019 #endif
1020         return status;
1021 
1022 #ifdef CONFIG_PROC_FS
1023 cleanup_logger:
1024         nf_log_unregister(&nfulnl_logger);
1025 #endif
1026 cleanup_subsys:
1027         nfnetlink_subsys_unregister(&nfulnl_subsys);
1028 cleanup_netlink_notifier:
1029         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1030         return status;
1031 }
1032 
1033 static void __exit nfnetlink_log_fini(void)
1034 {
1035         nf_log_unregister(&nfulnl_logger);
1036 #ifdef CONFIG_PROC_FS
1037         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1038 #endif
1039         nfnetlink_subsys_unregister(&nfulnl_subsys);
1040         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1041 }
1042 
1043 MODULE_DESCRIPTION("netfilter userspace logging");
1044 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1045 MODULE_LICENSE("GPL");
1046 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1047 
1048 module_init(nfnetlink_log_init);
1049 module_exit(nfnetlink_log_fini);
1050 

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