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> | |
5 | * | |
6 | * 2000/09/22 ulog-cprange feature added | |
7 | * 2001/01/04 in-kernel queue as proposed by Sebastian Zander | |
8 | * <zander@fokus.gmd.de> | |
9 | * 2001/01/30 per-rule nlgroup conflicts with global queue. | |
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 | * | |
26 | * This module accepts two parameters: | |
27 | * | |
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 | * | |
38 | * flushtimeout: | |
39 | * Specify, after how many hundredths of a second the queue should be | |
40 | * flushed even if it is not full yet. | |
41 | * | |
42 | * ipt_ULOG.c,v 1.22 2002/10/30 09:07:31 laforge Exp | |
43 | */ | |
44 | ||
45 | #include <linux/module.h> | |
46 | #include <linux/config.h> | |
47 | #include <linux/spinlock.h> | |
48 | #include <linux/socket.h> | |
49 | #include <linux/skbuff.h> | |
50 | #include <linux/kernel.h> | |
51 | #include <linux/timer.h> | |
52 | #include <linux/netlink.h> | |
53 | #include <linux/netdevice.h> | |
54 | #include <linux/mm.h> | |
55 | #include <linux/moduleparam.h> | |
56 | #include <linux/netfilter.h> | |
57 | #include <linux/netfilter_ipv4/ip_tables.h> | |
58 | #include <linux/netfilter_ipv4/ipt_ULOG.h> | |
1da177e4 LT |
59 | #include <net/sock.h> |
60 | #include <linux/bitops.h> | |
61 | ||
62 | MODULE_LICENSE("GPL"); | |
63 | MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); | |
64 | MODULE_DESCRIPTION("iptables userspace logging module"); | |
4fdb3bb7 | 65 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG); |
1da177e4 LT |
66 | |
67 | #define ULOG_NL_EVENT 111 /* Harald's favorite number */ | |
68 | #define ULOG_MAXNLGROUPS 32 /* numer of nlgroups */ | |
69 | ||
70 | #if 0 | |
71 | #define DEBUGP(format, args...) printk("%s:%s:" format, \ | |
72 | __FILE__, __FUNCTION__ , ## args) | |
73 | #else | |
74 | #define DEBUGP(format, args...) | |
75 | #endif | |
76 | ||
77 | #define PRINTR(format, args...) do { if (net_ratelimit()) printk(format , ## args); } while (0) | |
78 | ||
79 | static unsigned int nlbufsiz = 4096; | |
80 | module_param(nlbufsiz, uint, 0600); /* FIXME: Check size < 128k --RR */ | |
81 | MODULE_PARM_DESC(nlbufsiz, "netlink buffer size"); | |
82 | ||
83 | static unsigned int flushtimeout = 10; | |
84 | module_param(flushtimeout, int, 0600); | |
85 | MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)"); | |
86 | ||
87 | static unsigned int nflog = 1; | |
88 | module_param(nflog, int, 0400); | |
89 | MODULE_PARM_DESC(nflog, "register as internal netfilter logging module"); | |
90 | ||
91 | /* global data structures */ | |
92 | ||
93 | typedef struct { | |
94 | unsigned int qlen; /* number of nlmsgs' in the skb */ | |
95 | struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */ | |
96 | struct sk_buff *skb; /* the pre-allocated skb */ | |
97 | struct timer_list timer; /* the timer function */ | |
98 | } ulog_buff_t; | |
99 | ||
100 | static ulog_buff_t ulog_buffers[ULOG_MAXNLGROUPS]; /* array of buffers */ | |
101 | ||
e45b1be8 PM |
102 | static struct sock *nflognl; /* our socket */ |
103 | static DEFINE_SPINLOCK(ulog_lock); /* spinlock */ | |
1da177e4 LT |
104 | |
105 | /* send one ulog_buff_t to userspace */ | |
106 | static void ulog_send(unsigned int nlgroupnum) | |
107 | { | |
108 | ulog_buff_t *ub = &ulog_buffers[nlgroupnum]; | |
109 | ||
110 | if (timer_pending(&ub->timer)) { | |
111 | DEBUGP("ipt_ULOG: ulog_send: timer was pending, deleting\n"); | |
112 | del_timer(&ub->timer); | |
113 | } | |
114 | ||
115 | /* last nlmsg needs NLMSG_DONE */ | |
116 | if (ub->qlen > 1) | |
117 | ub->lastnlh->nlmsg_type = NLMSG_DONE; | |
118 | ||
ac6d439d PM |
119 | NETLINK_CB(ub->skb).dst_group = nlgroupnum + 1; |
120 | DEBUGP("ipt_ULOG: throwing %d packets to netlink group %u\n", | |
121 | ub->qlen, nlgroupnum + 1); | |
122 | netlink_broadcast(nflognl, ub->skb, 0, nlgroupnum + 1, GFP_ATOMIC); | |
1da177e4 LT |
123 | |
124 | ub->qlen = 0; | |
125 | ub->skb = NULL; | |
126 | ub->lastnlh = NULL; | |
127 | ||
128 | } | |
129 | ||
130 | ||
131 | /* timer function to flush queue in flushtimeout time */ | |
132 | static void ulog_timer(unsigned long data) | |
133 | { | |
134 | DEBUGP("ipt_ULOG: timer function called, calling ulog_send\n"); | |
135 | ||
136 | /* lock to protect against somebody modifying our structure | |
137 | * from ipt_ulog_target at the same time */ | |
e45b1be8 | 138 | spin_lock_bh(&ulog_lock); |
1da177e4 | 139 | ulog_send(data); |
e45b1be8 | 140 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
141 | } |
142 | ||
143 | static struct sk_buff *ulog_alloc_skb(unsigned int size) | |
144 | { | |
145 | struct sk_buff *skb; | |
146 | ||
147 | /* alloc skb which should be big enough for a whole | |
148 | * multipart message. WARNING: has to be <= 131000 | |
149 | * due to slab allocator restrictions */ | |
150 | ||
151 | skb = alloc_skb(nlbufsiz, GFP_ATOMIC); | |
152 | if (!skb) { | |
153 | PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n", | |
154 | nlbufsiz); | |
155 | ||
156 | /* try to allocate only as much as we need for | |
157 | * current packet */ | |
158 | ||
159 | skb = alloc_skb(size, GFP_ATOMIC); | |
160 | if (!skb) | |
161 | PRINTR("ipt_ULOG: can't even allocate %ub\n", size); | |
162 | } | |
163 | ||
164 | return skb; | |
165 | } | |
166 | ||
167 | static void ipt_ulog_packet(unsigned int hooknum, | |
168 | const struct sk_buff *skb, | |
169 | const struct net_device *in, | |
170 | const struct net_device *out, | |
171 | const struct ipt_ulog_info *loginfo, | |
172 | const char *prefix) | |
173 | { | |
174 | ulog_buff_t *ub; | |
175 | ulog_packet_msg_t *pm; | |
176 | size_t size, copy_len; | |
177 | struct nlmsghdr *nlh; | |
178 | ||
179 | /* ffs == find first bit set, necessary because userspace | |
180 | * is already shifting groupnumber, but we need unshifted. | |
181 | * ffs() returns [1..32], we need [0..31] */ | |
182 | unsigned int groupnum = ffs(loginfo->nl_group) - 1; | |
183 | ||
184 | /* calculate the size of the skb needed */ | |
185 | if ((loginfo->copy_range == 0) || | |
186 | (loginfo->copy_range > skb->len)) { | |
187 | copy_len = skb->len; | |
188 | } else { | |
189 | copy_len = loginfo->copy_range; | |
190 | } | |
191 | ||
192 | size = NLMSG_SPACE(sizeof(*pm) + copy_len); | |
193 | ||
194 | ub = &ulog_buffers[groupnum]; | |
195 | ||
e45b1be8 | 196 | spin_lock_bh(&ulog_lock); |
1da177e4 LT |
197 | |
198 | if (!ub->skb) { | |
199 | if (!(ub->skb = ulog_alloc_skb(size))) | |
200 | goto alloc_failure; | |
201 | } else if (ub->qlen >= loginfo->qthreshold || | |
202 | size > skb_tailroom(ub->skb)) { | |
203 | /* either the queue len is too high or we don't have | |
204 | * enough room in nlskb left. send it to userspace. */ | |
205 | ||
206 | ulog_send(groupnum); | |
207 | ||
208 | if (!(ub->skb = ulog_alloc_skb(size))) | |
209 | goto alloc_failure; | |
210 | } | |
211 | ||
212 | DEBUGP("ipt_ULOG: qlen %d, qthreshold %d\n", ub->qlen, | |
213 | loginfo->qthreshold); | |
214 | ||
215 | /* NLMSG_PUT contains a hidden goto nlmsg_failure !!! */ | |
216 | nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT, | |
217 | sizeof(*pm)+copy_len); | |
218 | ub->qlen++; | |
219 | ||
220 | pm = NLMSG_DATA(nlh); | |
221 | ||
222 | /* We might not have a timestamp, get one */ | |
a61bbcf2 PM |
223 | if (skb->tstamp.off_sec == 0) |
224 | __net_timestamp((struct sk_buff *)skb); | |
1da177e4 LT |
225 | |
226 | /* copy hook, prefix, timestamp, payload, etc. */ | |
227 | pm->data_len = copy_len; | |
a61bbcf2 PM |
228 | pm->timestamp_sec = skb_tv_base.tv_sec + skb->tstamp.off_sec; |
229 | pm->timestamp_usec = skb_tv_base.tv_usec + skb->tstamp.off_usec; | |
1da177e4 LT |
230 | pm->mark = skb->nfmark; |
231 | pm->hook = hooknum; | |
232 | if (prefix != NULL) | |
233 | strncpy(pm->prefix, prefix, sizeof(pm->prefix)); | |
234 | else if (loginfo->prefix[0] != '\0') | |
235 | strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix)); | |
236 | else | |
237 | *(pm->prefix) = '\0'; | |
238 | ||
239 | if (in && in->hard_header_len > 0 | |
240 | && skb->mac.raw != (void *) skb->nh.iph | |
241 | && in->hard_header_len <= ULOG_MAC_LEN) { | |
242 | memcpy(pm->mac, skb->mac.raw, in->hard_header_len); | |
243 | pm->mac_len = in->hard_header_len; | |
244 | } else | |
245 | pm->mac_len = 0; | |
246 | ||
247 | if (in) | |
248 | strncpy(pm->indev_name, in->name, sizeof(pm->indev_name)); | |
249 | else | |
250 | pm->indev_name[0] = '\0'; | |
251 | ||
252 | if (out) | |
253 | strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name)); | |
254 | else | |
255 | pm->outdev_name[0] = '\0'; | |
256 | ||
257 | /* copy_len <= skb->len, so can't fail. */ | |
258 | if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0) | |
259 | BUG(); | |
260 | ||
261 | /* check if we are building multi-part messages */ | |
262 | if (ub->qlen > 1) { | |
263 | ub->lastnlh->nlmsg_flags |= NLM_F_MULTI; | |
264 | } | |
265 | ||
266 | ub->lastnlh = nlh; | |
267 | ||
268 | /* if timer isn't already running, start it */ | |
269 | if (!timer_pending(&ub->timer)) { | |
270 | ub->timer.expires = jiffies + flushtimeout * HZ / 100; | |
271 | add_timer(&ub->timer); | |
272 | } | |
273 | ||
274 | /* if threshold is reached, send message to userspace */ | |
275 | if (ub->qlen >= loginfo->qthreshold) { | |
276 | if (loginfo->qthreshold > 1) | |
277 | nlh->nlmsg_type = NLMSG_DONE; | |
278 | ulog_send(groupnum); | |
279 | } | |
280 | ||
e45b1be8 | 281 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
282 | |
283 | return; | |
284 | ||
285 | nlmsg_failure: | |
286 | PRINTR("ipt_ULOG: error during NLMSG_PUT\n"); | |
287 | ||
288 | alloc_failure: | |
289 | PRINTR("ipt_ULOG: Error building netlink message\n"); | |
290 | ||
e45b1be8 | 291 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
292 | } |
293 | ||
294 | static unsigned int ipt_ulog_target(struct sk_buff **pskb, | |
295 | const struct net_device *in, | |
296 | const struct net_device *out, | |
297 | unsigned int hooknum, | |
298 | const void *targinfo, void *userinfo) | |
299 | { | |
300 | struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; | |
301 | ||
302 | ipt_ulog_packet(hooknum, *pskb, in, out, loginfo, NULL); | |
303 | ||
304 | return IPT_CONTINUE; | |
305 | } | |
306 | ||
608c8e4f HW |
307 | static void ipt_logfn(unsigned int pf, |
308 | unsigned int hooknum, | |
1da177e4 LT |
309 | const struct sk_buff *skb, |
310 | const struct net_device *in, | |
311 | const struct net_device *out, | |
608c8e4f | 312 | const struct nf_loginfo *li, |
1da177e4 LT |
313 | const char *prefix) |
314 | { | |
608c8e4f HW |
315 | struct ipt_ulog_info loginfo; |
316 | ||
317 | if (!li || li->type != NF_LOG_TYPE_ULOG) { | |
318 | loginfo.nl_group = ULOG_DEFAULT_NLGROUP; | |
319 | loginfo.copy_range = 0; | |
320 | loginfo.qthreshold = ULOG_DEFAULT_QTHRESHOLD; | |
321 | loginfo.prefix[0] = '\0'; | |
322 | } else { | |
323 | loginfo.nl_group = li->u.ulog.group; | |
324 | loginfo.copy_range = li->u.ulog.copy_len; | |
325 | loginfo.qthreshold = li->u.ulog.qthreshold; | |
326 | strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix)); | |
327 | } | |
1da177e4 LT |
328 | |
329 | ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix); | |
330 | } | |
331 | ||
332 | static int ipt_ulog_checkentry(const char *tablename, | |
333 | const struct ipt_entry *e, | |
334 | void *targinfo, | |
335 | unsigned int targinfosize, | |
336 | unsigned int hookmask) | |
337 | { | |
338 | struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo; | |
339 | ||
340 | if (targinfosize != IPT_ALIGN(sizeof(struct ipt_ulog_info))) { | |
341 | DEBUGP("ipt_ULOG: targinfosize %u != 0\n", targinfosize); | |
342 | return 0; | |
343 | } | |
344 | ||
345 | if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') { | |
346 | DEBUGP("ipt_ULOG: prefix term %i\n", | |
347 | loginfo->prefix[sizeof(loginfo->prefix) - 1]); | |
348 | return 0; | |
349 | } | |
350 | ||
351 | if (loginfo->qthreshold > ULOG_MAX_QLEN) { | |
352 | DEBUGP("ipt_ULOG: queue threshold %i > MAX_QLEN\n", | |
353 | loginfo->qthreshold); | |
354 | return 0; | |
355 | } | |
356 | ||
357 | return 1; | |
358 | } | |
359 | ||
360 | static struct ipt_target ipt_ulog_reg = { | |
361 | .name = "ULOG", | |
362 | .target = ipt_ulog_target, | |
363 | .checkentry = ipt_ulog_checkentry, | |
364 | .me = THIS_MODULE, | |
365 | }; | |
366 | ||
608c8e4f HW |
367 | static struct nf_logger ipt_ulog_logger = { |
368 | .name = "ipt_ULOG", | |
369 | .logfn = &ipt_logfn, | |
370 | .me = THIS_MODULE, | |
371 | }; | |
372 | ||
1da177e4 LT |
373 | static int __init init(void) |
374 | { | |
375 | int i; | |
376 | ||
377 | DEBUGP("ipt_ULOG: init module\n"); | |
378 | ||
379 | if (nlbufsiz >= 128*1024) { | |
380 | printk("Netlink buffer has to be <= 128kB\n"); | |
381 | return -EINVAL; | |
382 | } | |
383 | ||
384 | /* initialize ulog_buffers */ | |
385 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) { | |
386 | init_timer(&ulog_buffers[i].timer); | |
387 | ulog_buffers[i].timer.function = ulog_timer; | |
388 | ulog_buffers[i].timer.data = i; | |
389 | } | |
390 | ||
06628607 PM |
391 | nflognl = netlink_kernel_create(NETLINK_NFLOG, ULOG_MAXNLGROUPS, NULL, |
392 | THIS_MODULE); | |
1da177e4 LT |
393 | if (!nflognl) |
394 | return -ENOMEM; | |
395 | ||
396 | if (ipt_register_target(&ipt_ulog_reg) != 0) { | |
397 | sock_release(nflognl->sk_socket); | |
398 | return -EINVAL; | |
399 | } | |
400 | if (nflog) | |
608c8e4f | 401 | nf_log_register(PF_INET, &ipt_ulog_logger); |
1da177e4 LT |
402 | |
403 | return 0; | |
404 | } | |
405 | ||
406 | static void __exit fini(void) | |
407 | { | |
408 | ulog_buff_t *ub; | |
409 | int i; | |
410 | ||
411 | DEBUGP("ipt_ULOG: cleanup_module\n"); | |
412 | ||
413 | if (nflog) | |
608c8e4f | 414 | nf_log_unregister_logger(&ipt_ulog_logger); |
1da177e4 LT |
415 | ipt_unregister_target(&ipt_ulog_reg); |
416 | sock_release(nflognl->sk_socket); | |
417 | ||
418 | /* remove pending timers and free allocated skb's */ | |
419 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) { | |
420 | ub = &ulog_buffers[i]; | |
421 | if (timer_pending(&ub->timer)) { | |
422 | DEBUGP("timer was pending, deleting\n"); | |
423 | del_timer(&ub->timer); | |
424 | } | |
425 | ||
426 | if (ub->skb) { | |
427 | kfree_skb(ub->skb); | |
428 | ub->skb = NULL; | |
429 | } | |
430 | } | |
431 | ||
432 | } | |
433 | ||
434 | module_init(init); | |
435 | module_exit(fini); |