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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * netfilter module for userspace packet logging daemons | |
3 | * | |
4 | * (C) 2000-2004 by Harald Welte <laforge@netfilter.org> | |
5 | * | |
6 | * 2000/09/22 ulog-cprange feature added | |
e905a9ed | 7 | * 2001/01/04 in-kernel queue as proposed by Sebastian Zander |
1da177e4 | 8 | * <zander@fokus.gmd.de> |
e905a9ed | 9 | * 2001/01/30 per-rule nlgroup conflicts with global queue. |
1da177e4 LT |
10 | * nlgroup now global (sysctl) |
11 | * 2001/04/19 ulog-queue reworked, now fixed buffer size specified at | |
12 | * module loadtime -HW | |
13 | * 2002/07/07 remove broken nflog_rcv() function -HW | |
14 | * 2002/08/29 fix shifted/unshifted nlgroup bug -HW | |
15 | * 2002/10/30 fix uninitialized mac_len field - <Anders K. Pedersen> | |
16 | * 2004/10/25 fix erroneous calculation of 'len' parameter to NLMSG_PUT | |
17 | * resulting in bogus 'error during NLMSG_PUT' messages. | |
18 | * | |
19 | * (C) 1999-2001 Paul `Rusty' Russell | |
20 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
21 | * | |
22 | * This program is free software; you can redistribute it and/or modify | |
23 | * it under the terms of the GNU General Public License version 2 as | |
24 | * published by the Free Software Foundation. | |
25 | * | |
e905a9ed YH |
26 | * This module accepts two parameters: |
27 | * | |
1da177e4 LT |
28 | * nlbufsiz: |
29 | * The parameter specifies how big the buffer for each netlink multicast | |
30 | * group is. e.g. If you say nlbufsiz=8192, up to eight kb of packets will | |
31 | * get accumulated in the kernel until they are sent to userspace. It is | |
32 | * NOT possible to allocate more than 128kB, and it is strongly discouraged, | |
33 | * because atomically allocating 128kB inside the network rx softirq is not | |
34 | * reliable. Please also keep in mind that this buffer size is allocated for | |
35 | * each nlgroup you are using, so the total kernel memory usage increases | |
36 | * by that factor. | |
37 | * | |
c2db2924 HE |
38 | * Actually you should use nlbufsiz a bit smaller than PAGE_SIZE, since |
39 | * nlbufsiz is used with alloc_skb, which adds another | |
40 | * sizeof(struct skb_shared_info). Use NLMSG_GOODSIZE instead. | |
41 | * | |
1da177e4 LT |
42 | * flushtimeout: |
43 | * Specify, after how many hundredths of a second the queue should be | |
44 | * flushed even if it is not full yet. | |
45 | * | |
46 | * ipt_ULOG.c,v 1.22 2002/10/30 09:07:31 laforge Exp | |
47 | */ | |
48 | ||
49 | #include <linux/module.h> | |
1da177e4 LT |
50 | #include <linux/spinlock.h> |
51 | #include <linux/socket.h> | |
52 | #include <linux/skbuff.h> | |
53 | #include <linux/kernel.h> | |
54 | #include <linux/timer.h> | |
55 | #include <linux/netlink.h> | |
56 | #include <linux/netdevice.h> | |
57 | #include <linux/mm.h> | |
58 | #include <linux/moduleparam.h> | |
59 | #include <linux/netfilter.h> | |
6709dbbb | 60 | #include <linux/netfilter/x_tables.h> |
1da177e4 | 61 | #include <linux/netfilter_ipv4/ipt_ULOG.h> |
1da177e4 LT |
62 | #include <net/sock.h> |
63 | #include <linux/bitops.h> | |
01102e7c | 64 | #include <asm/unaligned.h> |
1da177e4 LT |
65 | |
66 | MODULE_LICENSE("GPL"); | |
67 | MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); | |
68 | MODULE_DESCRIPTION("iptables userspace logging module"); | |
4fdb3bb7 | 69 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG); |
1da177e4 LT |
70 | |
71 | #define ULOG_NL_EVENT 111 /* Harald's favorite number */ | |
72 | #define ULOG_MAXNLGROUPS 32 /* numer of nlgroups */ | |
73 | ||
74 | #if 0 | |
75 | #define DEBUGP(format, args...) printk("%s:%s:" format, \ | |
e905a9ed | 76 | __FILE__, __FUNCTION__ , ## args) |
1da177e4 LT |
77 | #else |
78 | #define DEBUGP(format, args...) | |
79 | #endif | |
80 | ||
81 | #define PRINTR(format, args...) do { if (net_ratelimit()) printk(format , ## args); } while (0) | |
82 | ||
c2db2924 | 83 | static unsigned int nlbufsiz = NLMSG_GOODSIZE; |
e7be6994 | 84 | module_param(nlbufsiz, uint, 0400); |
1da177e4 LT |
85 | MODULE_PARM_DESC(nlbufsiz, "netlink buffer size"); |
86 | ||
87 | static unsigned int flushtimeout = 10; | |
e7be6994 | 88 | module_param(flushtimeout, uint, 0600); |
1da177e4 LT |
89 | MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)"); |
90 | ||
e7be6994 PM |
91 | static int nflog = 1; |
92 | module_param(nflog, bool, 0400); | |
1da177e4 LT |
93 | MODULE_PARM_DESC(nflog, "register as internal netfilter logging module"); |
94 | ||
95 | /* global data structures */ | |
96 | ||
97 | typedef struct { | |
98 | unsigned int qlen; /* number of nlmsgs' in the skb */ | |
99 | struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */ | |
100 | struct sk_buff *skb; /* the pre-allocated skb */ | |
101 | struct timer_list timer; /* the timer function */ | |
102 | } ulog_buff_t; | |
103 | ||
104 | static ulog_buff_t ulog_buffers[ULOG_MAXNLGROUPS]; /* array of buffers */ | |
105 | ||
e45b1be8 PM |
106 | static struct sock *nflognl; /* our socket */ |
107 | static DEFINE_SPINLOCK(ulog_lock); /* spinlock */ | |
1da177e4 LT |
108 | |
109 | /* send one ulog_buff_t to userspace */ | |
110 | static void ulog_send(unsigned int nlgroupnum) | |
111 | { | |
112 | ulog_buff_t *ub = &ulog_buffers[nlgroupnum]; | |
113 | ||
114 | if (timer_pending(&ub->timer)) { | |
115 | DEBUGP("ipt_ULOG: ulog_send: timer was pending, deleting\n"); | |
116 | del_timer(&ub->timer); | |
117 | } | |
118 | ||
dcb7cd97 MH |
119 | if (!ub->skb) { |
120 | DEBUGP("ipt_ULOG: ulog_send: nothing to send\n"); | |
121 | return; | |
122 | } | |
123 | ||
1da177e4 LT |
124 | /* last nlmsg needs NLMSG_DONE */ |
125 | if (ub->qlen > 1) | |
126 | ub->lastnlh->nlmsg_type = NLMSG_DONE; | |
127 | ||
ac6d439d PM |
128 | NETLINK_CB(ub->skb).dst_group = nlgroupnum + 1; |
129 | DEBUGP("ipt_ULOG: throwing %d packets to netlink group %u\n", | |
130 | ub->qlen, nlgroupnum + 1); | |
131 | netlink_broadcast(nflognl, ub->skb, 0, nlgroupnum + 1, GFP_ATOMIC); | |
1da177e4 LT |
132 | |
133 | ub->qlen = 0; | |
134 | ub->skb = NULL; | |
135 | ub->lastnlh = NULL; | |
1da177e4 LT |
136 | } |
137 | ||
138 | ||
139 | /* timer function to flush queue in flushtimeout time */ | |
140 | static void ulog_timer(unsigned long data) | |
141 | { | |
142 | DEBUGP("ipt_ULOG: timer function called, calling ulog_send\n"); | |
143 | ||
144 | /* lock to protect against somebody modifying our structure | |
145 | * from ipt_ulog_target at the same time */ | |
e45b1be8 | 146 | spin_lock_bh(&ulog_lock); |
1da177e4 | 147 | ulog_send(data); |
e45b1be8 | 148 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
149 | } |
150 | ||
151 | static struct sk_buff *ulog_alloc_skb(unsigned int size) | |
152 | { | |
153 | struct sk_buff *skb; | |
ad2ad0f9 | 154 | unsigned int n; |
1da177e4 LT |
155 | |
156 | /* alloc skb which should be big enough for a whole | |
157 | * multipart message. WARNING: has to be <= 131000 | |
158 | * due to slab allocator restrictions */ | |
159 | ||
ad2ad0f9 PM |
160 | n = max(size, nlbufsiz); |
161 | skb = alloc_skb(n, GFP_ATOMIC); | |
1da177e4 | 162 | if (!skb) { |
ad2ad0f9 | 163 | PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n", n); |
1da177e4 | 164 | |
ad2ad0f9 | 165 | if (n > size) { |
e905a9ed | 166 | /* try to allocate only as much as we need for |
ad2ad0f9 | 167 | * current packet */ |
1da177e4 | 168 | |
ad2ad0f9 PM |
169 | skb = alloc_skb(size, GFP_ATOMIC); |
170 | if (!skb) | |
171 | PRINTR("ipt_ULOG: can't even allocate %ub\n", | |
172 | size); | |
173 | } | |
1da177e4 LT |
174 | } |
175 | ||
176 | return skb; | |
177 | } | |
178 | ||
179 | static void ipt_ulog_packet(unsigned int hooknum, | |
180 | const struct sk_buff *skb, | |
181 | const struct net_device *in, | |
182 | const struct net_device *out, | |
183 | const struct ipt_ulog_info *loginfo, | |
184 | const char *prefix) | |
185 | { | |
186 | ulog_buff_t *ub; | |
187 | ulog_packet_msg_t *pm; | |
188 | size_t size, copy_len; | |
189 | struct nlmsghdr *nlh; | |
b7aa0bf7 | 190 | struct timeval tv; |
1da177e4 LT |
191 | |
192 | /* ffs == find first bit set, necessary because userspace | |
193 | * is already shifting groupnumber, but we need unshifted. | |
194 | * ffs() returns [1..32], we need [0..31] */ | |
195 | unsigned int groupnum = ffs(loginfo->nl_group) - 1; | |
196 | ||
197 | /* calculate the size of the skb needed */ | |
198 | if ((loginfo->copy_range == 0) || | |
199 | (loginfo->copy_range > skb->len)) { | |
200 | copy_len = skb->len; | |
201 | } else { | |
202 | copy_len = loginfo->copy_range; | |
203 | } | |
204 | ||
205 | size = NLMSG_SPACE(sizeof(*pm) + copy_len); | |
206 | ||
207 | ub = &ulog_buffers[groupnum]; | |
e905a9ed | 208 | |
e45b1be8 | 209 | spin_lock_bh(&ulog_lock); |
1da177e4 LT |
210 | |
211 | if (!ub->skb) { | |
212 | if (!(ub->skb = ulog_alloc_skb(size))) | |
213 | goto alloc_failure; | |
214 | } else if (ub->qlen >= loginfo->qthreshold || | |
215 | size > skb_tailroom(ub->skb)) { | |
e905a9ed | 216 | /* either the queue len is too high or we don't have |
1da177e4 LT |
217 | * enough room in nlskb left. send it to userspace. */ |
218 | ||
219 | ulog_send(groupnum); | |
220 | ||
221 | if (!(ub->skb = ulog_alloc_skb(size))) | |
222 | goto alloc_failure; | |
223 | } | |
224 | ||
e905a9ed | 225 | DEBUGP("ipt_ULOG: qlen %d, qthreshold %d\n", ub->qlen, |
1da177e4 LT |
226 | loginfo->qthreshold); |
227 | ||
228 | /* NLMSG_PUT contains a hidden goto nlmsg_failure !!! */ | |
e905a9ed | 229 | nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT, |
1da177e4 LT |
230 | sizeof(*pm)+copy_len); |
231 | ub->qlen++; | |
232 | ||
233 | pm = NLMSG_DATA(nlh); | |
234 | ||
235 | /* We might not have a timestamp, get one */ | |
b7aa0bf7 | 236 | if (skb->tstamp.tv64 == 0) |
a61bbcf2 | 237 | __net_timestamp((struct sk_buff *)skb); |
1da177e4 LT |
238 | |
239 | /* copy hook, prefix, timestamp, payload, etc. */ | |
240 | pm->data_len = copy_len; | |
b7aa0bf7 ED |
241 | tv = ktime_to_timeval(skb->tstamp); |
242 | put_unaligned(tv.tv_sec, &pm->timestamp_sec); | |
243 | put_unaligned(tv.tv_usec, &pm->timestamp_usec); | |
01102e7c | 244 | put_unaligned(skb->mark, &pm->mark); |
1da177e4 LT |
245 | pm->hook = hooknum; |
246 | if (prefix != NULL) | |
247 | strncpy(pm->prefix, prefix, sizeof(pm->prefix)); | |
248 | else if (loginfo->prefix[0] != '\0') | |
249 | strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix)); | |
250 | else | |
251 | *(pm->prefix) = '\0'; | |
252 | ||
253 | if (in && in->hard_header_len > 0 | |
254 | && skb->mac.raw != (void *) skb->nh.iph | |
255 | && in->hard_header_len <= ULOG_MAC_LEN) { | |
256 | memcpy(pm->mac, skb->mac.raw, in->hard_header_len); | |
257 | pm->mac_len = in->hard_header_len; | |
258 | } else | |
259 | pm->mac_len = 0; | |
260 | ||
261 | if (in) | |
262 | strncpy(pm->indev_name, in->name, sizeof(pm->indev_name)); | |
263 | else | |
264 | pm->indev_name[0] = '\0'; | |
265 | ||
266 | if (out) | |
267 | strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name)); | |
268 | else | |
269 | pm->outdev_name[0] = '\0'; | |
270 | ||
271 | /* copy_len <= skb->len, so can't fail. */ | |
272 | if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0) | |
273 | BUG(); | |
e905a9ed | 274 | |
1da177e4 LT |
275 | /* check if we are building multi-part messages */ |
276 | if (ub->qlen > 1) { | |
277 | ub->lastnlh->nlmsg_flags |= NLM_F_MULTI; | |
278 | } | |
279 | ||
280 | ub->lastnlh = nlh; | |
281 | ||
282 | /* if timer isn't already running, start it */ | |
283 | if (!timer_pending(&ub->timer)) { | |
284 | ub->timer.expires = jiffies + flushtimeout * HZ / 100; | |
285 | add_timer(&ub->timer); | |
286 | } | |
287 | ||
288 | /* if threshold is reached, send message to userspace */ | |
289 | if (ub->qlen >= loginfo->qthreshold) { | |
290 | if (loginfo->qthreshold > 1) | |
291 | nlh->nlmsg_type = NLMSG_DONE; | |
292 | ulog_send(groupnum); | |
293 | } | |
294 | ||
e45b1be8 | 295 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
296 | |
297 | return; | |
298 | ||
299 | nlmsg_failure: | |
300 | PRINTR("ipt_ULOG: error during NLMSG_PUT\n"); | |
301 | ||
302 | alloc_failure: | |
303 | PRINTR("ipt_ULOG: Error building netlink message\n"); | |
304 | ||
e45b1be8 | 305 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
306 | } |
307 | ||
308 | static unsigned int ipt_ulog_target(struct sk_buff **pskb, | |
309 | const struct net_device *in, | |
310 | const struct net_device *out, | |
311 | unsigned int hooknum, | |
c4986734 | 312 | const struct xt_target *target, |
fe1cb108 | 313 | const void *targinfo) |
1da177e4 LT |
314 | { |
315 | struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; | |
316 | ||
317 | ipt_ulog_packet(hooknum, *pskb, in, out, loginfo, NULL); | |
e905a9ed | 318 | |
6709dbbb | 319 | return XT_CONTINUE; |
1da177e4 | 320 | } |
e905a9ed | 321 | |
608c8e4f HW |
322 | static void ipt_logfn(unsigned int pf, |
323 | unsigned int hooknum, | |
1da177e4 LT |
324 | const struct sk_buff *skb, |
325 | const struct net_device *in, | |
326 | const struct net_device *out, | |
608c8e4f | 327 | const struct nf_loginfo *li, |
1da177e4 LT |
328 | const char *prefix) |
329 | { | |
608c8e4f HW |
330 | struct ipt_ulog_info loginfo; |
331 | ||
332 | if (!li || li->type != NF_LOG_TYPE_ULOG) { | |
333 | loginfo.nl_group = ULOG_DEFAULT_NLGROUP; | |
334 | loginfo.copy_range = 0; | |
335 | loginfo.qthreshold = ULOG_DEFAULT_QTHRESHOLD; | |
336 | loginfo.prefix[0] = '\0'; | |
337 | } else { | |
338 | loginfo.nl_group = li->u.ulog.group; | |
339 | loginfo.copy_range = li->u.ulog.copy_len; | |
340 | loginfo.qthreshold = li->u.ulog.qthreshold; | |
341 | strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix)); | |
342 | } | |
1da177e4 LT |
343 | |
344 | ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix); | |
345 | } | |
346 | ||
347 | static int ipt_ulog_checkentry(const char *tablename, | |
2e4e6a17 | 348 | const void *e, |
c4986734 | 349 | const struct xt_target *target, |
1da177e4 | 350 | void *targinfo, |
1da177e4 LT |
351 | unsigned int hookmask) |
352 | { | |
353 | struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; | |
354 | ||
1da177e4 LT |
355 | if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') { |
356 | DEBUGP("ipt_ULOG: prefix term %i\n", | |
357 | loginfo->prefix[sizeof(loginfo->prefix) - 1]); | |
358 | return 0; | |
359 | } | |
1da177e4 LT |
360 | if (loginfo->qthreshold > ULOG_MAX_QLEN) { |
361 | DEBUGP("ipt_ULOG: queue threshold %i > MAX_QLEN\n", | |
362 | loginfo->qthreshold); | |
363 | return 0; | |
364 | } | |
1da177e4 LT |
365 | return 1; |
366 | } | |
367 | ||
6709dbbb | 368 | static struct xt_target ipt_ulog_reg = { |
1da177e4 | 369 | .name = "ULOG", |
6709dbbb | 370 | .family = AF_INET, |
1da177e4 | 371 | .target = ipt_ulog_target, |
1d5cd909 | 372 | .targetsize = sizeof(struct ipt_ulog_info), |
1da177e4 LT |
373 | .checkentry = ipt_ulog_checkentry, |
374 | .me = THIS_MODULE, | |
375 | }; | |
376 | ||
608c8e4f HW |
377 | static struct nf_logger ipt_ulog_logger = { |
378 | .name = "ipt_ULOG", | |
1d5cd909 | 379 | .logfn = ipt_logfn, |
608c8e4f HW |
380 | .me = THIS_MODULE, |
381 | }; | |
382 | ||
65b4b4e8 | 383 | static int __init ipt_ulog_init(void) |
1da177e4 | 384 | { |
e1fd0586 | 385 | int ret, i; |
1da177e4 LT |
386 | |
387 | DEBUGP("ipt_ULOG: init module\n"); | |
388 | ||
e7be6994 | 389 | if (nlbufsiz > 128*1024) { |
1da177e4 LT |
390 | printk("Netlink buffer has to be <= 128kB\n"); |
391 | return -EINVAL; | |
392 | } | |
393 | ||
394 | /* initialize ulog_buffers */ | |
395 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) { | |
396 | init_timer(&ulog_buffers[i].timer); | |
397 | ulog_buffers[i].timer.function = ulog_timer; | |
398 | ulog_buffers[i].timer.data = i; | |
399 | } | |
400 | ||
06628607 | 401 | nflognl = netlink_kernel_create(NETLINK_NFLOG, ULOG_MAXNLGROUPS, NULL, |
e905a9ed | 402 | THIS_MODULE); |
1da177e4 LT |
403 | if (!nflognl) |
404 | return -ENOMEM; | |
405 | ||
6709dbbb | 406 | ret = xt_register_target(&ipt_ulog_reg); |
e1fd0586 | 407 | if (ret < 0) { |
1da177e4 | 408 | sock_release(nflognl->sk_socket); |
e1fd0586 | 409 | return ret; |
1da177e4 LT |
410 | } |
411 | if (nflog) | |
608c8e4f | 412 | nf_log_register(PF_INET, &ipt_ulog_logger); |
e905a9ed | 413 | |
1da177e4 LT |
414 | return 0; |
415 | } | |
416 | ||
65b4b4e8 | 417 | static void __exit ipt_ulog_fini(void) |
1da177e4 LT |
418 | { |
419 | ulog_buff_t *ub; | |
420 | int i; | |
421 | ||
422 | DEBUGP("ipt_ULOG: cleanup_module\n"); | |
423 | ||
424 | if (nflog) | |
e92ad99c | 425 | nf_log_unregister(&ipt_ulog_logger); |
6709dbbb | 426 | xt_unregister_target(&ipt_ulog_reg); |
1da177e4 LT |
427 | sock_release(nflognl->sk_socket); |
428 | ||
429 | /* remove pending timers and free allocated skb's */ | |
430 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) { | |
431 | ub = &ulog_buffers[i]; | |
432 | if (timer_pending(&ub->timer)) { | |
433 | DEBUGP("timer was pending, deleting\n"); | |
434 | del_timer(&ub->timer); | |
435 | } | |
436 | ||
437 | if (ub->skb) { | |
438 | kfree_skb(ub->skb); | |
439 | ub->skb = NULL; | |
440 | } | |
441 | } | |
1da177e4 LT |
442 | } |
443 | ||
65b4b4e8 AM |
444 | module_init(ipt_ulog_init); |
445 | module_exit(ipt_ulog_fini); |