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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> | |
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 | 31 | */ |
ff67e4e4 | 32 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
1da177e4 | 33 | #include <linux/module.h> |
1da177e4 LT |
34 | #include <linux/spinlock.h> |
35 | #include <linux/socket.h> | |
5a0e3ad6 | 36 | #include <linux/slab.h> |
1da177e4 LT |
37 | #include <linux/skbuff.h> |
38 | #include <linux/kernel.h> | |
39 | #include <linux/timer.h> | |
40 | #include <linux/netlink.h> | |
41 | #include <linux/netdevice.h> | |
42 | #include <linux/mm.h> | |
43 | #include <linux/moduleparam.h> | |
44 | #include <linux/netfilter.h> | |
6709dbbb | 45 | #include <linux/netfilter/x_tables.h> |
1da177e4 | 46 | #include <linux/netfilter_ipv4/ipt_ULOG.h> |
f01ffbd6 | 47 | #include <net/netfilter/nf_log.h> |
1da177e4 LT |
48 | #include <net/sock.h> |
49 | #include <linux/bitops.h> | |
01102e7c | 50 | #include <asm/unaligned.h> |
1da177e4 LT |
51 | |
52 | MODULE_LICENSE("GPL"); | |
53 | MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); | |
2ae15b64 | 54 | MODULE_DESCRIPTION("Xtables: packet logging to netlink using ULOG"); |
4fdb3bb7 | 55 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG); |
1da177e4 LT |
56 | |
57 | #define ULOG_NL_EVENT 111 /* Harald's favorite number */ | |
58 | #define ULOG_MAXNLGROUPS 32 /* numer of nlgroups */ | |
59 | ||
c2db2924 | 60 | static unsigned int nlbufsiz = NLMSG_GOODSIZE; |
e7be6994 | 61 | module_param(nlbufsiz, uint, 0400); |
1da177e4 LT |
62 | MODULE_PARM_DESC(nlbufsiz, "netlink buffer size"); |
63 | ||
64 | static unsigned int flushtimeout = 10; | |
e7be6994 | 65 | module_param(flushtimeout, uint, 0600); |
1da177e4 LT |
66 | MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)"); |
67 | ||
eb939922 | 68 | static bool nflog = true; |
e7be6994 | 69 | module_param(nflog, bool, 0400); |
1da177e4 LT |
70 | MODULE_PARM_DESC(nflog, "register as internal netfilter logging module"); |
71 | ||
72 | /* global data structures */ | |
73 | ||
74 | typedef struct { | |
75 | unsigned int qlen; /* number of nlmsgs' in the skb */ | |
76 | struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */ | |
77 | struct sk_buff *skb; /* the pre-allocated skb */ | |
78 | struct timer_list timer; /* the timer function */ | |
79 | } ulog_buff_t; | |
80 | ||
81 | static ulog_buff_t ulog_buffers[ULOG_MAXNLGROUPS]; /* array of buffers */ | |
82 | ||
e45b1be8 PM |
83 | static struct sock *nflognl; /* our socket */ |
84 | static DEFINE_SPINLOCK(ulog_lock); /* spinlock */ | |
1da177e4 LT |
85 | |
86 | /* send one ulog_buff_t to userspace */ | |
87 | static void ulog_send(unsigned int nlgroupnum) | |
88 | { | |
89 | ulog_buff_t *ub = &ulog_buffers[nlgroupnum]; | |
90 | ||
91 | if (timer_pending(&ub->timer)) { | |
ff67e4e4 | 92 | pr_debug("ulog_send: timer was pending, deleting\n"); |
1da177e4 LT |
93 | del_timer(&ub->timer); |
94 | } | |
95 | ||
dcb7cd97 | 96 | if (!ub->skb) { |
ff67e4e4 | 97 | pr_debug("ulog_send: nothing to send\n"); |
dcb7cd97 MH |
98 | return; |
99 | } | |
100 | ||
1da177e4 LT |
101 | /* last nlmsg needs NLMSG_DONE */ |
102 | if (ub->qlen > 1) | |
103 | ub->lastnlh->nlmsg_type = NLMSG_DONE; | |
104 | ||
ac6d439d | 105 | NETLINK_CB(ub->skb).dst_group = nlgroupnum + 1; |
ff67e4e4 | 106 | pr_debug("throwing %d packets to netlink group %u\n", |
0d53778e | 107 | ub->qlen, nlgroupnum + 1); |
ac6d439d | 108 | netlink_broadcast(nflognl, ub->skb, 0, nlgroupnum + 1, GFP_ATOMIC); |
1da177e4 LT |
109 | |
110 | ub->qlen = 0; | |
111 | ub->skb = NULL; | |
112 | ub->lastnlh = NULL; | |
1da177e4 LT |
113 | } |
114 | ||
115 | ||
116 | /* timer function to flush queue in flushtimeout time */ | |
117 | static void ulog_timer(unsigned long data) | |
118 | { | |
ff67e4e4 | 119 | pr_debug("timer function called, calling ulog_send\n"); |
1da177e4 LT |
120 | |
121 | /* lock to protect against somebody modifying our structure | |
122 | * from ipt_ulog_target at the same time */ | |
e45b1be8 | 123 | spin_lock_bh(&ulog_lock); |
1da177e4 | 124 | ulog_send(data); |
e45b1be8 | 125 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
126 | } |
127 | ||
128 | static struct sk_buff *ulog_alloc_skb(unsigned int size) | |
129 | { | |
130 | struct sk_buff *skb; | |
ad2ad0f9 | 131 | unsigned int n; |
1da177e4 LT |
132 | |
133 | /* alloc skb which should be big enough for a whole | |
134 | * multipart message. WARNING: has to be <= 131000 | |
135 | * due to slab allocator restrictions */ | |
136 | ||
ad2ad0f9 | 137 | n = max(size, nlbufsiz); |
0a9ee813 | 138 | skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN); |
1da177e4 | 139 | if (!skb) { |
ad2ad0f9 | 140 | if (n > size) { |
e905a9ed | 141 | /* try to allocate only as much as we need for |
ad2ad0f9 | 142 | * current packet */ |
1da177e4 | 143 | |
ad2ad0f9 PM |
144 | skb = alloc_skb(size, GFP_ATOMIC); |
145 | if (!skb) | |
ff67e4e4 | 146 | pr_debug("cannot even allocate %ub\n", size); |
ad2ad0f9 | 147 | } |
1da177e4 LT |
148 | } |
149 | ||
150 | return skb; | |
151 | } | |
152 | ||
153 | static void ipt_ulog_packet(unsigned int hooknum, | |
154 | const struct sk_buff *skb, | |
155 | const struct net_device *in, | |
156 | const struct net_device *out, | |
157 | const struct ipt_ulog_info *loginfo, | |
158 | const char *prefix) | |
159 | { | |
160 | ulog_buff_t *ub; | |
161 | ulog_packet_msg_t *pm; | |
162 | size_t size, copy_len; | |
163 | struct nlmsghdr *nlh; | |
b7aa0bf7 | 164 | struct timeval tv; |
1da177e4 LT |
165 | |
166 | /* ffs == find first bit set, necessary because userspace | |
167 | * is already shifting groupnumber, but we need unshifted. | |
168 | * ffs() returns [1..32], we need [0..31] */ | |
169 | unsigned int groupnum = ffs(loginfo->nl_group) - 1; | |
170 | ||
171 | /* calculate the size of the skb needed */ | |
7c4e36bc | 172 | if (loginfo->copy_range == 0 || loginfo->copy_range > skb->len) |
1da177e4 | 173 | copy_len = skb->len; |
7c4e36bc | 174 | else |
1da177e4 | 175 | copy_len = loginfo->copy_range; |
1da177e4 LT |
176 | |
177 | size = NLMSG_SPACE(sizeof(*pm) + copy_len); | |
178 | ||
179 | ub = &ulog_buffers[groupnum]; | |
e905a9ed | 180 | |
e45b1be8 | 181 | spin_lock_bh(&ulog_lock); |
1da177e4 LT |
182 | |
183 | if (!ub->skb) { | |
184 | if (!(ub->skb = ulog_alloc_skb(size))) | |
185 | goto alloc_failure; | |
186 | } else if (ub->qlen >= loginfo->qthreshold || | |
187 | size > skb_tailroom(ub->skb)) { | |
e905a9ed | 188 | /* either the queue len is too high or we don't have |
1da177e4 LT |
189 | * enough room in nlskb left. send it to userspace. */ |
190 | ||
191 | ulog_send(groupnum); | |
192 | ||
193 | if (!(ub->skb = ulog_alloc_skb(size))) | |
194 | goto alloc_failure; | |
195 | } | |
196 | ||
ff67e4e4 | 197 | pr_debug("qlen %d, qthreshold %Zu\n", ub->qlen, loginfo->qthreshold); |
1da177e4 | 198 | |
c2bd4baf DM |
199 | nlh = nlmsg_put(ub->skb, 0, ub->qlen, ULOG_NL_EVENT, |
200 | sizeof(*pm)+copy_len, 0); | |
201 | if (!nlh) { | |
202 | pr_debug("error during nlmsg_put\n"); | |
203 | goto out_unlock; | |
204 | } | |
1da177e4 LT |
205 | ub->qlen++; |
206 | ||
c2bd4baf | 207 | pm = nlmsg_data(nlh); |
1da177e4 LT |
208 | |
209 | /* We might not have a timestamp, get one */ | |
b7aa0bf7 | 210 | if (skb->tstamp.tv64 == 0) |
a61bbcf2 | 211 | __net_timestamp((struct sk_buff *)skb); |
1da177e4 LT |
212 | |
213 | /* copy hook, prefix, timestamp, payload, etc. */ | |
214 | pm->data_len = copy_len; | |
b7aa0bf7 ED |
215 | tv = ktime_to_timeval(skb->tstamp); |
216 | put_unaligned(tv.tv_sec, &pm->timestamp_sec); | |
217 | put_unaligned(tv.tv_usec, &pm->timestamp_usec); | |
01102e7c | 218 | put_unaligned(skb->mark, &pm->mark); |
1da177e4 LT |
219 | pm->hook = hooknum; |
220 | if (prefix != NULL) | |
221 | strncpy(pm->prefix, prefix, sizeof(pm->prefix)); | |
222 | else if (loginfo->prefix[0] != '\0') | |
223 | strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix)); | |
224 | else | |
225 | *(pm->prefix) = '\0'; | |
226 | ||
3666ed1c JP |
227 | if (in && in->hard_header_len > 0 && |
228 | skb->mac_header != skb->network_header && | |
229 | in->hard_header_len <= ULOG_MAC_LEN) { | |
98e399f8 | 230 | memcpy(pm->mac, skb_mac_header(skb), in->hard_header_len); |
1da177e4 LT |
231 | pm->mac_len = in->hard_header_len; |
232 | } else | |
233 | pm->mac_len = 0; | |
234 | ||
235 | if (in) | |
236 | strncpy(pm->indev_name, in->name, sizeof(pm->indev_name)); | |
237 | else | |
238 | pm->indev_name[0] = '\0'; | |
239 | ||
240 | if (out) | |
241 | strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name)); | |
242 | else | |
243 | pm->outdev_name[0] = '\0'; | |
244 | ||
245 | /* copy_len <= skb->len, so can't fail. */ | |
246 | if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0) | |
247 | BUG(); | |
e905a9ed | 248 | |
1da177e4 | 249 | /* check if we are building multi-part messages */ |
7c4e36bc | 250 | if (ub->qlen > 1) |
1da177e4 | 251 | ub->lastnlh->nlmsg_flags |= NLM_F_MULTI; |
1da177e4 LT |
252 | |
253 | ub->lastnlh = nlh; | |
254 | ||
255 | /* if timer isn't already running, start it */ | |
256 | if (!timer_pending(&ub->timer)) { | |
257 | ub->timer.expires = jiffies + flushtimeout * HZ / 100; | |
258 | add_timer(&ub->timer); | |
259 | } | |
260 | ||
261 | /* if threshold is reached, send message to userspace */ | |
262 | if (ub->qlen >= loginfo->qthreshold) { | |
263 | if (loginfo->qthreshold > 1) | |
264 | nlh->nlmsg_type = NLMSG_DONE; | |
265 | ulog_send(groupnum); | |
266 | } | |
c2bd4baf | 267 | out_unlock: |
e45b1be8 | 268 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
269 | |
270 | return; | |
271 | ||
1da177e4 | 272 | alloc_failure: |
ff67e4e4 | 273 | pr_debug("Error building netlink message\n"); |
e45b1be8 | 274 | spin_unlock_bh(&ulog_lock); |
1da177e4 LT |
275 | } |
276 | ||
d3c5ee6d | 277 | static unsigned int |
4b560b44 | 278 | ulog_tg(struct sk_buff *skb, const struct xt_action_param *par) |
1da177e4 | 279 | { |
7eb35586 JE |
280 | ipt_ulog_packet(par->hooknum, skb, par->in, par->out, |
281 | par->targinfo, NULL); | |
6709dbbb | 282 | return XT_CONTINUE; |
1da177e4 | 283 | } |
e905a9ed | 284 | |
76108cea | 285 | static void ipt_logfn(u_int8_t pf, |
608c8e4f | 286 | unsigned int hooknum, |
1da177e4 LT |
287 | const struct sk_buff *skb, |
288 | const struct net_device *in, | |
289 | const struct net_device *out, | |
608c8e4f | 290 | const struct nf_loginfo *li, |
1da177e4 LT |
291 | const char *prefix) |
292 | { | |
608c8e4f HW |
293 | struct ipt_ulog_info loginfo; |
294 | ||
295 | if (!li || li->type != NF_LOG_TYPE_ULOG) { | |
296 | loginfo.nl_group = ULOG_DEFAULT_NLGROUP; | |
297 | loginfo.copy_range = 0; | |
298 | loginfo.qthreshold = ULOG_DEFAULT_QTHRESHOLD; | |
299 | loginfo.prefix[0] = '\0'; | |
300 | } else { | |
301 | loginfo.nl_group = li->u.ulog.group; | |
302 | loginfo.copy_range = li->u.ulog.copy_len; | |
303 | loginfo.qthreshold = li->u.ulog.qthreshold; | |
304 | strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix)); | |
305 | } | |
1da177e4 LT |
306 | |
307 | ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix); | |
308 | } | |
309 | ||
135367b8 | 310 | static int ulog_tg_check(const struct xt_tgchk_param *par) |
1da177e4 | 311 | { |
af5d6dc2 | 312 | const struct ipt_ulog_info *loginfo = par->targinfo; |
1da177e4 | 313 | |
1da177e4 | 314 | if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') { |
ff67e4e4 | 315 | pr_debug("prefix not null-terminated\n"); |
d6b00a53 | 316 | return -EINVAL; |
1da177e4 | 317 | } |
1da177e4 | 318 | if (loginfo->qthreshold > ULOG_MAX_QLEN) { |
ff67e4e4 | 319 | pr_debug("queue threshold %Zu > MAX_QLEN\n", |
0d53778e | 320 | loginfo->qthreshold); |
d6b00a53 | 321 | return -EINVAL; |
1da177e4 | 322 | } |
d6b00a53 | 323 | return 0; |
1da177e4 LT |
324 | } |
325 | ||
b076deb8 PM |
326 | #ifdef CONFIG_COMPAT |
327 | struct compat_ipt_ulog_info { | |
328 | compat_uint_t nl_group; | |
329 | compat_size_t copy_range; | |
330 | compat_size_t qthreshold; | |
331 | char prefix[ULOG_PREFIX_LEN]; | |
332 | }; | |
333 | ||
739674fb | 334 | static void ulog_tg_compat_from_user(void *dst, const void *src) |
b076deb8 | 335 | { |
a47362a2 | 336 | const struct compat_ipt_ulog_info *cl = src; |
b076deb8 PM |
337 | struct ipt_ulog_info l = { |
338 | .nl_group = cl->nl_group, | |
339 | .copy_range = cl->copy_range, | |
340 | .qthreshold = cl->qthreshold, | |
341 | }; | |
342 | ||
343 | memcpy(l.prefix, cl->prefix, sizeof(l.prefix)); | |
344 | memcpy(dst, &l, sizeof(l)); | |
345 | } | |
346 | ||
739674fb | 347 | static int ulog_tg_compat_to_user(void __user *dst, const void *src) |
b076deb8 | 348 | { |
a47362a2 | 349 | const struct ipt_ulog_info *l = src; |
b076deb8 PM |
350 | struct compat_ipt_ulog_info cl = { |
351 | .nl_group = l->nl_group, | |
352 | .copy_range = l->copy_range, | |
353 | .qthreshold = l->qthreshold, | |
354 | }; | |
355 | ||
356 | memcpy(cl.prefix, l->prefix, sizeof(cl.prefix)); | |
357 | return copy_to_user(dst, &cl, sizeof(cl)) ? -EFAULT : 0; | |
358 | } | |
359 | #endif /* CONFIG_COMPAT */ | |
360 | ||
d3c5ee6d | 361 | static struct xt_target ulog_tg_reg __read_mostly = { |
1da177e4 | 362 | .name = "ULOG", |
ee999d8b | 363 | .family = NFPROTO_IPV4, |
d3c5ee6d | 364 | .target = ulog_tg, |
1d5cd909 | 365 | .targetsize = sizeof(struct ipt_ulog_info), |
d3c5ee6d | 366 | .checkentry = ulog_tg_check, |
b076deb8 PM |
367 | #ifdef CONFIG_COMPAT |
368 | .compatsize = sizeof(struct compat_ipt_ulog_info), | |
d3c5ee6d JE |
369 | .compat_from_user = ulog_tg_compat_from_user, |
370 | .compat_to_user = ulog_tg_compat_to_user, | |
b076deb8 | 371 | #endif |
1da177e4 LT |
372 | .me = THIS_MODULE, |
373 | }; | |
374 | ||
ca735b3a | 375 | static struct nf_logger ipt_ulog_logger __read_mostly = { |
608c8e4f | 376 | .name = "ipt_ULOG", |
1d5cd909 | 377 | .logfn = ipt_logfn, |
608c8e4f HW |
378 | .me = THIS_MODULE, |
379 | }; | |
380 | ||
d3c5ee6d | 381 | static int __init ulog_tg_init(void) |
1da177e4 | 382 | { |
e1fd0586 | 383 | int ret, i; |
a31f2d17 PNA |
384 | struct netlink_kernel_cfg cfg = { |
385 | .groups = ULOG_MAXNLGROUPS, | |
386 | }; | |
1da177e4 | 387 | |
ff67e4e4 | 388 | pr_debug("init module\n"); |
1da177e4 | 389 | |
e7be6994 | 390 | if (nlbufsiz > 128*1024) { |
ff67e4e4 | 391 | pr_warning("Netlink buffer has to be <= 128kB\n"); |
1da177e4 LT |
392 | return -EINVAL; |
393 | } | |
394 | ||
395 | /* initialize ulog_buffers */ | |
e6f689db PM |
396 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) |
397 | setup_timer(&ulog_buffers[i].timer, ulog_timer, i); | |
1da177e4 | 398 | |
9f00d977 | 399 | nflognl = netlink_kernel_create(&init_net, NETLINK_NFLOG, &cfg); |
1da177e4 LT |
400 | if (!nflognl) |
401 | return -ENOMEM; | |
402 | ||
d3c5ee6d | 403 | ret = xt_register_target(&ulog_tg_reg); |
e1fd0586 | 404 | if (ret < 0) { |
b7c6ba6e | 405 | netlink_kernel_release(nflognl); |
e1fd0586 | 406 | return ret; |
1da177e4 LT |
407 | } |
408 | if (nflog) | |
ee999d8b | 409 | nf_log_register(NFPROTO_IPV4, &ipt_ulog_logger); |
e905a9ed | 410 | |
1da177e4 LT |
411 | return 0; |
412 | } | |
413 | ||
d3c5ee6d | 414 | static void __exit ulog_tg_exit(void) |
1da177e4 LT |
415 | { |
416 | ulog_buff_t *ub; | |
417 | int i; | |
418 | ||
ff67e4e4 | 419 | pr_debug("cleanup_module\n"); |
1da177e4 LT |
420 | |
421 | if (nflog) | |
e92ad99c | 422 | nf_log_unregister(&ipt_ulog_logger); |
d3c5ee6d | 423 | xt_unregister_target(&ulog_tg_reg); |
b7c6ba6e | 424 | netlink_kernel_release(nflognl); |
1da177e4 LT |
425 | |
426 | /* remove pending timers and free allocated skb's */ | |
427 | for (i = 0; i < ULOG_MAXNLGROUPS; i++) { | |
428 | ub = &ulog_buffers[i]; | |
429 | if (timer_pending(&ub->timer)) { | |
0d53778e | 430 | pr_debug("timer was pending, deleting\n"); |
1da177e4 LT |
431 | del_timer(&ub->timer); |
432 | } | |
433 | ||
434 | if (ub->skb) { | |
435 | kfree_skb(ub->skb); | |
436 | ub->skb = NULL; | |
437 | } | |
438 | } | |
1da177e4 LT |
439 | } |
440 | ||
d3c5ee6d JE |
441 | module_init(ulog_tg_init); |
442 | module_exit(ulog_tg_exit); |