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32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33#include <linux/module.h>
34#include <linux/spinlock.h>
35#include <linux/socket.h>
36#include <linux/slab.h>
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>
45#include <linux/netfilter/x_tables.h>
46#include <linux/netfilter_ipv4/ipt_ULOG.h>
47#include <net/netfilter/nf_log.h>
48#include <net/sock.h>
49#include <linux/bitops.h>
50#include <asm/unaligned.h>
51
52MODULE_LICENSE("GPL");
53MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
54MODULE_DESCRIPTION("Xtables: packet logging to netlink using ULOG");
55MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG);
56
57#define ULOG_NL_EVENT 111
58#define ULOG_MAXNLGROUPS 32
59
60static unsigned int nlbufsiz = NLMSG_GOODSIZE;
61module_param(nlbufsiz, uint, 0400);
62MODULE_PARM_DESC(nlbufsiz, "netlink buffer size");
63
64static unsigned int flushtimeout = 10;
65module_param(flushtimeout, uint, 0600);
66MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)");
67
68static int nflog = 1;
69module_param(nflog, bool, 0400);
70MODULE_PARM_DESC(nflog, "register as internal netfilter logging module");
71
72
73
74typedef struct {
75 unsigned int qlen;
76 struct nlmsghdr *lastnlh;
77 struct sk_buff *skb;
78 struct timer_list timer;
79} ulog_buff_t;
80
81static ulog_buff_t ulog_buffers[ULOG_MAXNLGROUPS];
82
83static struct sock *nflognl;
84static DEFINE_SPINLOCK(ulog_lock);
85
86
87static void ulog_send(unsigned int nlgroupnum)
88{
89 ulog_buff_t *ub = &ulog_buffers[nlgroupnum];
90
91 if (timer_pending(&ub->timer)) {
92 pr_debug("ulog_send: timer was pending, deleting\n");
93 del_timer(&ub->timer);
94 }
95
96 if (!ub->skb) {
97 pr_debug("ulog_send: nothing to send\n");
98 return;
99 }
100
101
102 if (ub->qlen > 1)
103 ub->lastnlh->nlmsg_type = NLMSG_DONE;
104
105 NETLINK_CB(ub->skb).dst_group = nlgroupnum + 1;
106 pr_debug("throwing %d packets to netlink group %u\n",
107 ub->qlen, nlgroupnum + 1);
108 netlink_broadcast(nflognl, ub->skb, 0, nlgroupnum + 1, GFP_ATOMIC);
109
110 ub->qlen = 0;
111 ub->skb = NULL;
112 ub->lastnlh = NULL;
113}
114
115
116
117static void ulog_timer(unsigned long data)
118{
119 pr_debug("timer function called, calling ulog_send\n");
120
121
122
123 spin_lock_bh(&ulog_lock);
124 ulog_send(data);
125 spin_unlock_bh(&ulog_lock);
126}
127
128static struct sk_buff *ulog_alloc_skb(unsigned int size)
129{
130 struct sk_buff *skb;
131 unsigned int n;
132
133
134
135
136
137 n = max(size, nlbufsiz);
138 skb = alloc_skb(n, GFP_ATOMIC);
139 if (!skb) {
140 pr_debug("cannot alloc whole buffer %ub!\n", n);
141
142 if (n > size) {
143
144
145
146 skb = alloc_skb(size, GFP_ATOMIC);
147 if (!skb)
148 pr_debug("cannot even allocate %ub\n", size);
149 }
150 }
151
152 return skb;
153}
154
155static void ipt_ulog_packet(unsigned int hooknum,
156 const struct sk_buff *skb,
157 const struct net_device *in,
158 const struct net_device *out,
159 const struct ipt_ulog_info *loginfo,
160 const char *prefix)
161{
162 ulog_buff_t *ub;
163 ulog_packet_msg_t *pm;
164 size_t size, copy_len;
165 struct nlmsghdr *nlh;
166 struct timeval tv;
167
168
169
170
171 unsigned int groupnum = ffs(loginfo->nl_group) - 1;
172
173
174 if (loginfo->copy_range == 0 || loginfo->copy_range > skb->len)
175 copy_len = skb->len;
176 else
177 copy_len = loginfo->copy_range;
178
179 size = NLMSG_SPACE(sizeof(*pm) + copy_len);
180
181 ub = &ulog_buffers[groupnum];
182
183 spin_lock_bh(&ulog_lock);
184
185 if (!ub->skb) {
186 if (!(ub->skb = ulog_alloc_skb(size)))
187 goto alloc_failure;
188 } else if (ub->qlen >= loginfo->qthreshold ||
189 size > skb_tailroom(ub->skb)) {
190
191
192
193 ulog_send(groupnum);
194
195 if (!(ub->skb = ulog_alloc_skb(size)))
196 goto alloc_failure;
197 }
198
199 pr_debug("qlen %d, qthreshold %Zu\n", ub->qlen, loginfo->qthreshold);
200
201
202 nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT,
203 sizeof(*pm)+copy_len);
204 ub->qlen++;
205
206 pm = NLMSG_DATA(nlh);
207
208
209 if (skb->tstamp.tv64 == 0)
210 __net_timestamp((struct sk_buff *)skb);
211
212
213 pm->data_len = copy_len;
214 tv = ktime_to_timeval(skb->tstamp);
215 put_unaligned(tv.tv_sec, &pm->timestamp_sec);
216 put_unaligned(tv.tv_usec, &pm->timestamp_usec);
217 put_unaligned(skb->mark, &pm->mark);
218 pm->hook = hooknum;
219 if (prefix != NULL)
220 strncpy(pm->prefix, prefix, sizeof(pm->prefix));
221 else if (loginfo->prefix[0] != '\0')
222 strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix));
223 else
224 *(pm->prefix) = '\0';
225
226 if (in && in->hard_header_len > 0 &&
227 skb->mac_header != skb->network_header &&
228 in->hard_header_len <= ULOG_MAC_LEN) {
229 memcpy(pm->mac, skb_mac_header(skb), in->hard_header_len);
230 pm->mac_len = in->hard_header_len;
231 } else
232 pm->mac_len = 0;
233
234 if (in)
235 strncpy(pm->indev_name, in->name, sizeof(pm->indev_name));
236 else
237 pm->indev_name[0] = '\0';
238
239 if (out)
240 strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name));
241 else
242 pm->outdev_name[0] = '\0';
243
244
245 if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0)
246 BUG();
247
248
249 if (ub->qlen > 1)
250 ub->lastnlh->nlmsg_flags |= NLM_F_MULTI;
251
252 ub->lastnlh = nlh;
253
254
255 if (!timer_pending(&ub->timer)) {
256 ub->timer.expires = jiffies + flushtimeout * HZ / 100;
257 add_timer(&ub->timer);
258 }
259
260
261 if (ub->qlen >= loginfo->qthreshold) {
262 if (loginfo->qthreshold > 1)
263 nlh->nlmsg_type = NLMSG_DONE;
264 ulog_send(groupnum);
265 }
266
267 spin_unlock_bh(&ulog_lock);
268
269 return;
270
271nlmsg_failure:
272 pr_debug("error during NLMSG_PUT\n");
273alloc_failure:
274 pr_debug("Error building netlink message\n");
275 spin_unlock_bh(&ulog_lock);
276}
277
278static unsigned int
279ulog_tg(struct sk_buff *skb, const struct xt_action_param *par)
280{
281 ipt_ulog_packet(par->hooknum, skb, par->in, par->out,
282 par->targinfo, NULL);
283 return XT_CONTINUE;
284}
285
286static void ipt_logfn(u_int8_t pf,
287 unsigned int hooknum,
288 const struct sk_buff *skb,
289 const struct net_device *in,
290 const struct net_device *out,
291 const struct nf_loginfo *li,
292 const char *prefix)
293{
294 struct ipt_ulog_info loginfo;
295
296 if (!li || li->type != NF_LOG_TYPE_ULOG) {
297 loginfo.nl_group = ULOG_DEFAULT_NLGROUP;
298 loginfo.copy_range = 0;
299 loginfo.qthreshold = ULOG_DEFAULT_QTHRESHOLD;
300 loginfo.prefix[0] = '\0';
301 } else {
302 loginfo.nl_group = li->u.ulog.group;
303 loginfo.copy_range = li->u.ulog.copy_len;
304 loginfo.qthreshold = li->u.ulog.qthreshold;
305 strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix));
306 }
307
308 ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix);
309}
310
311static int ulog_tg_check(const struct xt_tgchk_param *par)
312{
313 const struct ipt_ulog_info *loginfo = par->targinfo;
314
315 if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') {
316 pr_debug("prefix not null-terminated\n");
317 return -EINVAL;
318 }
319 if (loginfo->qthreshold > ULOG_MAX_QLEN) {
320 pr_debug("queue threshold %Zu > MAX_QLEN\n",
321 loginfo->qthreshold);
322 return -EINVAL;
323 }
324 return 0;
325}
326
327#ifdef CONFIG_COMPAT
328struct compat_ipt_ulog_info {
329 compat_uint_t nl_group;
330 compat_size_t copy_range;
331 compat_size_t qthreshold;
332 char prefix[ULOG_PREFIX_LEN];
333};
334
335static void ulog_tg_compat_from_user(void *dst, const void *src)
336{
337 const struct compat_ipt_ulog_info *cl = src;
338 struct ipt_ulog_info l = {
339 .nl_group = cl->nl_group,
340 .copy_range = cl->copy_range,
341 .qthreshold = cl->qthreshold,
342 };
343
344 memcpy(l.prefix, cl->prefix, sizeof(l.prefix));
345 memcpy(dst, &l, sizeof(l));
346}
347
348static int ulog_tg_compat_to_user(void __user *dst, const void *src)
349{
350 const struct ipt_ulog_info *l = src;
351 struct compat_ipt_ulog_info cl = {
352 .nl_group = l->nl_group,
353 .copy_range = l->copy_range,
354 .qthreshold = l->qthreshold,
355 };
356
357 memcpy(cl.prefix, l->prefix, sizeof(cl.prefix));
358 return copy_to_user(dst, &cl, sizeof(cl)) ? -EFAULT : 0;
359}
360#endif
361
362static struct xt_target ulog_tg_reg __read_mostly = {
363 .name = "ULOG",
364 .family = NFPROTO_IPV4,
365 .target = ulog_tg,
366 .targetsize = sizeof(struct ipt_ulog_info),
367 .checkentry = ulog_tg_check,
368#ifdef CONFIG_COMPAT
369 .compatsize = sizeof(struct compat_ipt_ulog_info),
370 .compat_from_user = ulog_tg_compat_from_user,
371 .compat_to_user = ulog_tg_compat_to_user,
372#endif
373 .me = THIS_MODULE,
374};
375
376static struct nf_logger ipt_ulog_logger __read_mostly = {
377 .name = "ipt_ULOG",
378 .logfn = ipt_logfn,
379 .me = THIS_MODULE,
380};
381
382static int __init ulog_tg_init(void)
383{
384 int ret, i;
385
386 pr_debug("init module\n");
387
388 if (nlbufsiz > 128*1024) {
389 pr_warning("Netlink buffer has to be <= 128kB\n");
390 return -EINVAL;
391 }
392
393
394 for (i = 0; i < ULOG_MAXNLGROUPS; i++)
395 setup_timer(&ulog_buffers[i].timer, ulog_timer, i);
396
397 nflognl = netlink_kernel_create(&init_net,
398 NETLINK_NFLOG, ULOG_MAXNLGROUPS, NULL,
399 NULL, THIS_MODULE);
400 if (!nflognl)
401 return -ENOMEM;
402
403 ret = xt_register_target(&ulog_tg_reg);
404 if (ret < 0) {
405 netlink_kernel_release(nflognl);
406 return ret;
407 }
408 if (nflog)
409 nf_log_register(NFPROTO_IPV4, &ipt_ulog_logger);
410
411 return 0;
412}
413
414static void __exit ulog_tg_exit(void)
415{
416 ulog_buff_t *ub;
417 int i;
418
419 pr_debug("cleanup_module\n");
420
421 if (nflog)
422 nf_log_unregister(&ipt_ulog_logger);
423 xt_unregister_target(&ulog_tg_reg);
424 netlink_kernel_release(nflognl);
425
426
427 for (i = 0; i < ULOG_MAXNLGROUPS; i++) {
428 ub = &ulog_buffers[i];
429 if (timer_pending(&ub->timer)) {
430 pr_debug("timer was pending, deleting\n");
431 del_timer(&ub->timer);
432 }
433
434 if (ub->skb) {
435 kfree_skb(ub->skb);
436 ub->skb = NULL;
437 }
438 }
439}
440
441module_init(ulog_tg_init);
442module_exit(ulog_tg_exit);
443