Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * netfilter module for userspace packet logging daemons | |
3 | * | |
4 | * (C) 2000-2004 by Harald Welte <laforge@netfilter.org> | |
1da177e4 LT |
5 | * (C) 1999-2001 Paul `Rusty' Russell |
6 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
e905a9ed YH |
12 | * This module accepts two parameters: |
13 | * | |
1da177e4 LT |
14 | * nlbufsiz: |
15 | * The parameter specifies how big the buffer for each netlink multicast | |
16 | * group is. e.g. If you say nlbufsiz=8192, up to eight kb of packets will | |
17 | * get accumulated in the kernel until they are sent to userspace. It is | |
18 | * NOT possible to allocate more than 128kB, and it is strongly discouraged, | |
19 | * because atomically allocating 128kB inside the network rx softirq is not | |
20 | * reliable. Please also keep in mind that this buffer size is allocated for | |
21 | * each nlgroup you are using, so the total kernel memory usage increases | |
22 | * by that factor. | |
23 | * | |
c2db2924 HE |
24 | * Actually you should use nlbufsiz a bit smaller than PAGE_SIZE, since |
25 | * nlbufsiz is used with alloc_skb, which adds another | |
26 | * sizeof(struct skb_shared_info). Use NLMSG_GOODSIZE instead. | |
27 | * | |
1da177e4 LT |
28 | * flushtimeout: |
29 | * Specify, after how many hundredths of a second the queue should be | |
30 | * flushed even if it is not full yet. | |
1da177e4 LT |
31 | */ |
32 | ||
33 | #include <linux/module.h> | |
1da177e4 LT |
34 | #include <linux/spinlock.h> |
35 | #include <linux/socket.h> | |
36 | #include <linux/skbuff.h> | |
37 | #include <linux/kernel.h> | |
38 | #include <linux/timer.h> | |
39 | #include <linux/netlink.h> | |
40 | #include <linux/netdevice.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/moduleparam.h> | |
43 | #include <linux/netfilter.h> | |
6709dbbb | 44 | #include <linux/netfilter/x_tables.h> |
1da177e4 | 45 | #include <linux/netfilter_ipv4/ipt_ULOG.h> |
1da177e4 LT |
46 | #include <net/sock.h> |
47 | #include <linux/bitops.h> | |
01102e7c | 48 | #include <asm/unaligned.h> |
1da177e4 LT |
49 | |
50 | MODULE_LICENSE("GPL"); | |
51 | MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); | |
52 | MODULE_DESCRIPTION("iptables userspace logging module"); | |
4fdb3bb7 | 53 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG); |
1da177e4 LT |
54 | |
55 | #define ULOG_NL_EVENT 111 /* Harald's favorite number */ | |
56 | #define ULOG_MAXNLGROUPS 32 /* numer of nlgroups */ | |
57 | ||
58 | #if 0 | |
59 | #define DEBUGP(format, args...) printk("%s:%s:" format, \ | |
e905a9ed | 60 | __FILE__, __FUNCTION__ , ## args) |
1da177e4 LT |
61 | #else |
62 | #define DEBUGP(format, args...) | |
63 | #endif | |
64 | ||
65 | #define PRINTR(format, args...) do { if (net_ratelimit()) printk(format , ## args); } while (0) | |
66 | ||
c2db2924 | 67 | static unsigned int nlbufsiz = NLMSG_GOODSIZE; |
e7be6994 | 68 | module_param(nlbufsiz, uint, 0400); |
1da177e4 LT |
69 | MODULE_PARM_DESC(nlbufsiz, "netlink buffer size"); |
70 | ||
71 | static unsigned int flushtimeout = 10; | |
e7be6994 | 72 | module_param(flushtimeout, uint, 0600); |
1da177e4 LT |
73 | MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)"); |
74 | ||
e7be6994 PM |
75 | static int nflog = 1; |
76 | module_param(nflog, bool, 0400); | |
1da177e4 LT |
77 | MODULE_PARM_DESC(nflog, "register as internal netfilter logging module"); |
78 | ||
79 | /* global data structures */ | |
80 | ||
81 | typedef struct { | |
82 | unsigned int qlen; /* number of nlmsgs' in the skb */ | |
83 | struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */ | |
84 | struct sk_buff *skb; /* the pre-allocated skb */ | |
85 | struct timer_list timer; /* the timer function */ | |
86 | } ulog_buff_t; | |
87 | ||
88 | static ulog_buff_t ulog_buffers[ULOG_MAXNLGROUPS]; /* array of buffers */ | |
89 | ||
e45b1be8 PM |
90 | static struct sock *nflognl; /* our socket */ |
91 | static DEFINE_SPINLOCK(ulog_lock); /* spinlock */ | |
1da177e4 LT |
92 | |
93 | /* send one ulog_buff_t to userspace */ | |
94 | static void ulog_send(unsigned int nlgroupnum) | |
95 | { | |
96 | ulog_buff_t *ub = &ulog_buffers[nlgroupnum]; | |
97 | ||
98 | if (timer_pending(&ub->timer)) { | |
99 | DEBUGP("ipt_ULOG: ulog_send: timer was pending, deleting\n"); | |
100 | del_timer(&ub->timer); | |
101 | } | |
102 | ||
dcb7cd97 MH |
103 | if (!ub->skb) { |
104 | DEBUGP("ipt_ULOG: ulog_send: nothing to send\n"); | |
105 | return; | |
106 | } | |
107 | ||
1da177e4 LT |
108 | /* last nlmsg needs NLMSG_DONE */ |
109 | if (ub->qlen > 1) | |
110 | ub->lastnlh->nlmsg_type = NLMSG_DONE; | |
111 | ||
ac6d439d PM |
112 | NETLINK_CB(ub->skb).dst_group = nlgroupnum + 1; |
113 | DEBUGP("ipt_ULOG: throwing %d packets to netlink group %u\n", | |
114 | ub->qlen, nlgroupnum + 1); | |
115 | netlink_broadcast(nflognl, ub->skb, 0, nlgroupnum + 1, GFP_ATOMIC); | |
1da177e4 LT |
116 | |
117 | ub->qlen = 0; | |
118 | ub->skb = NULL; | |
119 | ub->lastnlh = NULL; | |
1da177e4 LT |
120 | } |
121 | ||
122 | ||
123 | /* timer function to flush queue in flushtimeout time */ | |
124 | static void ulog_timer(unsigned long data) | |
125 | { | |
126 | DEBUGP("ipt_ULOG: timer function called, calling ulog_send\n"); | |
127 | ||
128 | /* lock to protect against somebody modifying our structure | |
129 | * from ipt_ulog_target at the same time */ | |
e45b1be8 | 130 | spin_lock_bh(&ulog_lock); |
1da177e4 | 131 | ulog_send(data); |
e45b1be8 | 132 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
133 | } |
134 | ||
135 | static struct sk_buff *ulog_alloc_skb(unsigned int size) | |
136 | { | |
137 | struct sk_buff *skb; | |
ad2ad0f9 | 138 | unsigned int n; |
1da177e4 LT |
139 | |
140 | /* alloc skb which should be big enough for a whole | |
141 | * multipart message. WARNING: has to be <= 131000 | |
142 | * due to slab allocator restrictions */ | |
143 | ||
ad2ad0f9 PM |
144 | n = max(size, nlbufsiz); |
145 | skb = alloc_skb(n, GFP_ATOMIC); | |
1da177e4 | 146 | if (!skb) { |
ad2ad0f9 | 147 | PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n", n); |
1da177e4 | 148 | |
ad2ad0f9 | 149 | if (n > size) { |
e905a9ed | 150 | /* try to allocate only as much as we need for |
ad2ad0f9 | 151 | * current packet */ |
1da177e4 | 152 | |
ad2ad0f9 PM |
153 | skb = alloc_skb(size, GFP_ATOMIC); |
154 | if (!skb) | |
155 | PRINTR("ipt_ULOG: can't even allocate %ub\n", | |
156 | size); | |
157 | } | |
1da177e4 LT |
158 | } |
159 | ||
160 | return skb; | |
161 | } | |
162 | ||
163 | static void ipt_ulog_packet(unsigned int hooknum, | |
164 | const struct sk_buff *skb, | |
165 | const struct net_device *in, | |
166 | const struct net_device *out, | |
167 | const struct ipt_ulog_info *loginfo, | |
168 | const char *prefix) | |
169 | { | |
170 | ulog_buff_t *ub; | |
171 | ulog_packet_msg_t *pm; | |
172 | size_t size, copy_len; | |
173 | struct nlmsghdr *nlh; | |
b7aa0bf7 | 174 | struct timeval tv; |
1da177e4 LT |
175 | |
176 | /* ffs == find first bit set, necessary because userspace | |
177 | * is already shifting groupnumber, but we need unshifted. | |
178 | * ffs() returns [1..32], we need [0..31] */ | |
179 | unsigned int groupnum = ffs(loginfo->nl_group) - 1; | |
180 | ||
181 | /* calculate the size of the skb needed */ | |
182 | if ((loginfo->copy_range == 0) || | |
183 | (loginfo->copy_range > skb->len)) { | |
184 | copy_len = skb->len; | |
185 | } else { | |
186 | copy_len = loginfo->copy_range; | |
187 | } | |
188 | ||
189 | size = NLMSG_SPACE(sizeof(*pm) + copy_len); | |
190 | ||
191 | ub = &ulog_buffers[groupnum]; | |
e905a9ed | 192 | |
e45b1be8 | 193 | spin_lock_bh(&ulog_lock); |
1da177e4 LT |
194 | |
195 | if (!ub->skb) { | |
196 | if (!(ub->skb = ulog_alloc_skb(size))) | |
197 | goto alloc_failure; | |
198 | } else if (ub->qlen >= loginfo->qthreshold || | |
199 | size > skb_tailroom(ub->skb)) { | |
e905a9ed | 200 | /* either the queue len is too high or we don't have |
1da177e4 LT |
201 | * enough room in nlskb left. send it to userspace. */ |
202 | ||
203 | ulog_send(groupnum); | |
204 | ||
205 | if (!(ub->skb = ulog_alloc_skb(size))) | |
206 | goto alloc_failure; | |
207 | } | |
208 | ||
e905a9ed | 209 | DEBUGP("ipt_ULOG: qlen %d, qthreshold %d\n", ub->qlen, |
1da177e4 LT |
210 | loginfo->qthreshold); |
211 | ||
212 | /* NLMSG_PUT contains a hidden goto nlmsg_failure !!! */ | |
e905a9ed | 213 | nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT, |
1da177e4 LT |
214 | sizeof(*pm)+copy_len); |
215 | ub->qlen++; | |
216 | ||
217 | pm = NLMSG_DATA(nlh); | |
218 | ||
219 | /* We might not have a timestamp, get one */ | |
b7aa0bf7 | 220 | if (skb->tstamp.tv64 == 0) |
a61bbcf2 | 221 | __net_timestamp((struct sk_buff *)skb); |
1da177e4 LT |
222 | |
223 | /* copy hook, prefix, timestamp, payload, etc. */ | |
224 | pm->data_len = copy_len; | |
b7aa0bf7 ED |
225 | tv = ktime_to_timeval(skb->tstamp); |
226 | put_unaligned(tv.tv_sec, &pm->timestamp_sec); | |
227 | put_unaligned(tv.tv_usec, &pm->timestamp_usec); | |
01102e7c | 228 | put_unaligned(skb->mark, &pm->mark); |
1da177e4 LT |
229 | pm->hook = hooknum; |
230 | if (prefix != NULL) | |
231 | strncpy(pm->prefix, prefix, sizeof(pm->prefix)); | |
232 | else if (loginfo->prefix[0] != '\0') | |
233 | strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix)); | |
234 | else | |
235 | *(pm->prefix) = '\0'; | |
236 | ||
237 | if (in && in->hard_header_len > 0 | |
b0e380b1 | 238 | && skb->mac_header != skb->network_header |
1da177e4 | 239 | && in->hard_header_len <= ULOG_MAC_LEN) { |
98e399f8 | 240 | memcpy(pm->mac, skb_mac_header(skb), in->hard_header_len); |
1da177e4 LT |
241 | pm->mac_len = in->hard_header_len; |
242 | } else | |
243 | pm->mac_len = 0; | |
244 | ||
245 | if (in) | |
246 | strncpy(pm->indev_name, in->name, sizeof(pm->indev_name)); | |
247 | else | |
248 | pm->indev_name[0] = '\0'; | |
249 | ||
250 | if (out) | |
251 | strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name)); | |
252 | else | |
253 | pm->outdev_name[0] = '\0'; | |
254 | ||
255 | /* copy_len <= skb->len, so can't fail. */ | |
256 | if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0) | |
257 | BUG(); | |
e905a9ed | 258 | |
1da177e4 LT |
259 | /* check if we are building multi-part messages */ |
260 | if (ub->qlen > 1) { | |
261 | ub->lastnlh->nlmsg_flags |= NLM_F_MULTI; | |
262 | } | |
263 | ||
264 | ub->lastnlh = nlh; | |
265 | ||
266 | /* if timer isn't already running, start it */ | |
267 | if (!timer_pending(&ub->timer)) { | |
268 | ub->timer.expires = jiffies + flushtimeout * HZ / 100; | |
269 | add_timer(&ub->timer); | |
270 | } | |
271 | ||
272 | /* if threshold is reached, send message to userspace */ | |
273 | if (ub->qlen >= loginfo->qthreshold) { | |
274 | if (loginfo->qthreshold > 1) | |
275 | nlh->nlmsg_type = NLMSG_DONE; | |
276 | ulog_send(groupnum); | |
277 | } | |
278 | ||
e45b1be8 | 279 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
280 | |
281 | return; | |
282 | ||
283 | nlmsg_failure: | |
284 | PRINTR("ipt_ULOG: error during NLMSG_PUT\n"); | |
285 | ||
286 | alloc_failure: | |
287 | PRINTR("ipt_ULOG: Error building netlink message\n"); | |
288 | ||
e45b1be8 | 289 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
290 | } |
291 | ||
292 | static unsigned int ipt_ulog_target(struct sk_buff **pskb, | |
293 | const struct net_device *in, | |
294 | const struct net_device *out, | |
295 | unsigned int hooknum, | |
c4986734 | 296 | const struct xt_target *target, |
fe1cb108 | 297 | const void *targinfo) |
1da177e4 LT |
298 | { |
299 | struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; | |
300 | ||
301 | ipt_ulog_packet(hooknum, *pskb, in, out, loginfo, NULL); | |
e905a9ed | 302 | |
6709dbbb | 303 | return XT_CONTINUE; |
1da177e4 | 304 | } |
e905a9ed | 305 | |
608c8e4f HW |
306 | static void ipt_logfn(unsigned int pf, |
307 | unsigned int hooknum, | |
1da177e4 LT |
308 | const struct sk_buff *skb, |
309 | const struct net_device *in, | |
310 | const struct net_device *out, | |
608c8e4f | 311 | const struct nf_loginfo *li, |
1da177e4 LT |
312 | const char *prefix) |
313 | { | |
608c8e4f HW |
314 | struct ipt_ulog_info loginfo; |
315 | ||
316 | if (!li || li->type != NF_LOG_TYPE_ULOG) { | |
317 | loginfo.nl_group = ULOG_DEFAULT_NLGROUP; | |
318 | loginfo.copy_range = 0; | |
319 | loginfo.qthreshold = ULOG_DEFAULT_QTHRESHOLD; | |
320 | loginfo.prefix[0] = '\0'; | |
321 | } else { | |
322 | loginfo.nl_group = li->u.ulog.group; | |
323 | loginfo.copy_range = li->u.ulog.copy_len; | |
324 | loginfo.qthreshold = li->u.ulog.qthreshold; | |
325 | strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix)); | |
326 | } | |
1da177e4 LT |
327 | |
328 | ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix); | |
329 | } | |
330 | ||
331 | static int ipt_ulog_checkentry(const char *tablename, | |
2e4e6a17 | 332 | const void *e, |
c4986734 | 333 | const struct xt_target *target, |
1da177e4 | 334 | void *targinfo, |
1da177e4 LT |
335 | unsigned int hookmask) |
336 | { | |
337 | struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; | |
338 | ||
1da177e4 LT |
339 | if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') { |
340 | DEBUGP("ipt_ULOG: prefix term %i\n", | |
341 | loginfo->prefix[sizeof(loginfo->prefix) - 1]); | |
342 | return 0; | |
343 | } | |
1da177e4 LT |
344 | if (loginfo->qthreshold > ULOG_MAX_QLEN) { |
345 | DEBUGP("ipt_ULOG: queue threshold %i > MAX_QLEN\n", | |
346 | loginfo->qthreshold); | |
347 | return 0; | |
348 | } | |
1da177e4 LT |
349 | return 1; |
350 | } | |
351 | ||
b076deb8 PM |
352 | #ifdef CONFIG_COMPAT |
353 | struct compat_ipt_ulog_info { | |
354 | compat_uint_t nl_group; | |
355 | compat_size_t copy_range; | |
356 | compat_size_t qthreshold; | |
357 | char prefix[ULOG_PREFIX_LEN]; | |
358 | }; | |
359 | ||
360 | static void compat_from_user(void *dst, void *src) | |
361 | { | |
362 | struct compat_ipt_ulog_info *cl = src; | |
363 | struct ipt_ulog_info l = { | |
364 | .nl_group = cl->nl_group, | |
365 | .copy_range = cl->copy_range, | |
366 | .qthreshold = cl->qthreshold, | |
367 | }; | |
368 | ||
369 | memcpy(l.prefix, cl->prefix, sizeof(l.prefix)); | |
370 | memcpy(dst, &l, sizeof(l)); | |
371 | } | |
372 | ||
373 | static int compat_to_user(void __user *dst, void *src) | |
374 | { | |
375 | struct ipt_ulog_info *l = src; | |
376 | struct compat_ipt_ulog_info cl = { | |
377 | .nl_group = l->nl_group, | |
378 | .copy_range = l->copy_range, | |
379 | .qthreshold = l->qthreshold, | |
380 | }; | |
381 | ||
382 | memcpy(cl.prefix, l->prefix, sizeof(cl.prefix)); | |
383 | return copy_to_user(dst, &cl, sizeof(cl)) ? -EFAULT : 0; | |
384 | } | |
385 | #endif /* CONFIG_COMPAT */ | |
386 | ||
6709dbbb | 387 | static struct xt_target ipt_ulog_reg = { |
1da177e4 | 388 | .name = "ULOG", |
6709dbbb | 389 | .family = AF_INET, |
1da177e4 | 390 | .target = ipt_ulog_target, |
1d5cd909 | 391 | .targetsize = sizeof(struct ipt_ulog_info), |
1da177e4 | 392 | .checkentry = ipt_ulog_checkentry, |
b076deb8 PM |
393 | #ifdef CONFIG_COMPAT |
394 | .compatsize = sizeof(struct compat_ipt_ulog_info), | |
395 | .compat_from_user = compat_from_user, | |
396 | .compat_to_user = compat_to_user, | |
397 | #endif | |
1da177e4 LT |
398 | .me = THIS_MODULE, |
399 | }; | |
400 | ||
608c8e4f HW |
401 | static struct nf_logger ipt_ulog_logger = { |
402 | .name = "ipt_ULOG", | |
1d5cd909 | 403 | .logfn = ipt_logfn, |
608c8e4f HW |
404 | .me = THIS_MODULE, |
405 | }; | |
406 | ||
65b4b4e8 | 407 | static int __init ipt_ulog_init(void) |
1da177e4 | 408 | { |
e1fd0586 | 409 | int ret, i; |
1da177e4 LT |
410 | |
411 | DEBUGP("ipt_ULOG: init module\n"); | |
412 | ||
e7be6994 | 413 | if (nlbufsiz > 128*1024) { |
1da177e4 LT |
414 | printk("Netlink buffer has to be <= 128kB\n"); |
415 | return -EINVAL; | |
416 | } | |
417 | ||
418 | /* initialize ulog_buffers */ | |
e6f689db PM |
419 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) |
420 | setup_timer(&ulog_buffers[i].timer, ulog_timer, i); | |
1da177e4 | 421 | |
06628607 | 422 | nflognl = netlink_kernel_create(NETLINK_NFLOG, ULOG_MAXNLGROUPS, NULL, |
af65bdfc | 423 | NULL, THIS_MODULE); |
1da177e4 LT |
424 | if (!nflognl) |
425 | return -ENOMEM; | |
426 | ||
6709dbbb | 427 | ret = xt_register_target(&ipt_ulog_reg); |
e1fd0586 | 428 | if (ret < 0) { |
1da177e4 | 429 | sock_release(nflognl->sk_socket); |
e1fd0586 | 430 | return ret; |
1da177e4 LT |
431 | } |
432 | if (nflog) | |
608c8e4f | 433 | nf_log_register(PF_INET, &ipt_ulog_logger); |
e905a9ed | 434 | |
1da177e4 LT |
435 | return 0; |
436 | } | |
437 | ||
65b4b4e8 | 438 | static void __exit ipt_ulog_fini(void) |
1da177e4 LT |
439 | { |
440 | ulog_buff_t *ub; | |
441 | int i; | |
442 | ||
443 | DEBUGP("ipt_ULOG: cleanup_module\n"); | |
444 | ||
445 | if (nflog) | |
e92ad99c | 446 | nf_log_unregister(&ipt_ulog_logger); |
6709dbbb | 447 | xt_unregister_target(&ipt_ulog_reg); |
1da177e4 LT |
448 | sock_release(nflognl->sk_socket); |
449 | ||
450 | /* remove pending timers and free allocated skb's */ | |
451 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) { | |
452 | ub = &ulog_buffers[i]; | |
453 | if (timer_pending(&ub->timer)) { | |
454 | DEBUGP("timer was pending, deleting\n"); | |
455 | del_timer(&ub->timer); | |
456 | } | |
457 | ||
458 | if (ub->skb) { | |
459 | kfree_skb(ub->skb); | |
460 | ub->skb = NULL; | |
461 | } | |
462 | } | |
1da177e4 LT |
463 | } |
464 | ||
65b4b4e8 AM |
465 | module_init(ipt_ulog_init); |
466 | module_exit(ipt_ulog_fini); |