2 * netfilter module for userspace packet logging daemons
4 * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
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
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.
19 * (C) 1999-2001 Paul `Rusty' Russell
20 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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.
26 * This module accepts two parameters:
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
39 * Specify, after how many hundredths of a second the queue should be
40 * flushed even if it is not full yet.
42 * ipt_ULOG.c,v 1.22 2002/10/30 09:07:31 laforge Exp
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>
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>
60 #include <linux/bitops.h>
62 MODULE_LICENSE("GPL");
63 MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
64 MODULE_DESCRIPTION("iptables userspace logging module");
65 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK
, NETLINK_NFLOG
);
67 #define ULOG_NL_EVENT 111 /* Harald's favorite number */
68 #define ULOG_MAXNLGROUPS 32 /* numer of nlgroups */
71 #define DEBUGP(format, args...) printk("%s:%s:" format, \
72 __FILE__, __FUNCTION__ , ## args)
74 #define DEBUGP(format, args...)
77 #define PRINTR(format, args...) do { if (net_ratelimit()) printk(format , ## args); } while (0)
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");
83 static unsigned int flushtimeout
= 10;
84 module_param(flushtimeout
, int, 0600);
85 MODULE_PARM_DESC(flushtimeout
, "buffer flush timeout (hundredths of a second)");
87 static unsigned int nflog
= 1;
88 module_param(nflog
, int, 0400);
89 MODULE_PARM_DESC(nflog
, "register as internal netfilter logging module");
91 /* global data structures */
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 */
100 static ulog_buff_t ulog_buffers
[ULOG_MAXNLGROUPS
]; /* array of buffers */
102 static struct sock
*nflognl
; /* our socket */
103 static DEFINE_SPINLOCK(ulog_lock
); /* spinlock */
105 /* send one ulog_buff_t to userspace */
106 static void ulog_send(unsigned int nlgroupnum
)
108 ulog_buff_t
*ub
= &ulog_buffers
[nlgroupnum
];
110 if (timer_pending(&ub
->timer
)) {
111 DEBUGP("ipt_ULOG: ulog_send: timer was pending, deleting\n");
112 del_timer(&ub
->timer
);
115 /* last nlmsg needs NLMSG_DONE */
117 ub
->lastnlh
->nlmsg_type
= NLMSG_DONE
;
119 NETLINK_CB(ub
->skb
).dst_groups
= (1 << nlgroupnum
);
120 DEBUGP("ipt_ULOG: throwing %d packets to netlink mask %u\n",
121 ub
->qlen
, nlgroupnum
);
122 netlink_broadcast(nflognl
, ub
->skb
, 0, (1 << nlgroupnum
), GFP_ATOMIC
);
131 /* timer function to flush queue in flushtimeout time */
132 static void ulog_timer(unsigned long data
)
134 DEBUGP("ipt_ULOG: timer function called, calling ulog_send\n");
136 /* lock to protect against somebody modifying our structure
137 * from ipt_ulog_target at the same time */
138 spin_lock_bh(&ulog_lock
);
140 spin_unlock_bh(&ulog_lock
);
143 static struct sk_buff
*ulog_alloc_skb(unsigned int size
)
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 */
151 skb
= alloc_skb(nlbufsiz
, GFP_ATOMIC
);
153 PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n",
156 /* try to allocate only as much as we need for
159 skb
= alloc_skb(size
, GFP_ATOMIC
);
161 PRINTR("ipt_ULOG: can't even allocate %ub\n", size
);
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
,
175 ulog_packet_msg_t
*pm
;
176 size_t size
, copy_len
;
177 struct nlmsghdr
*nlh
;
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;
184 /* calculate the size of the skb needed */
185 if ((loginfo
->copy_range
== 0) ||
186 (loginfo
->copy_range
> skb
->len
)) {
189 copy_len
= loginfo
->copy_range
;
192 size
= NLMSG_SPACE(sizeof(*pm
) + copy_len
);
194 ub
= &ulog_buffers
[groupnum
];
196 spin_lock_bh(&ulog_lock
);
199 if (!(ub
->skb
= ulog_alloc_skb(size
)))
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. */
208 if (!(ub
->skb
= ulog_alloc_skb(size
)))
212 DEBUGP("ipt_ULOG: qlen %d, qthreshold %d\n", ub
->qlen
,
213 loginfo
->qthreshold
);
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
);
220 pm
= NLMSG_DATA(nlh
);
222 /* We might not have a timestamp, get one */
223 if (skb
->stamp
.tv_sec
== 0)
224 do_gettimeofday((struct timeval
*)&skb
->stamp
);
226 /* copy hook, prefix, timestamp, payload, etc. */
227 pm
->data_len
= copy_len
;
228 pm
->timestamp_sec
= skb
->stamp
.tv_sec
;
229 pm
->timestamp_usec
= skb
->stamp
.tv_usec
;
230 pm
->mark
= skb
->nfmark
;
233 strncpy(pm
->prefix
, prefix
, sizeof(pm
->prefix
));
234 else if (loginfo
->prefix
[0] != '\0')
235 strncpy(pm
->prefix
, loginfo
->prefix
, sizeof(pm
->prefix
));
237 *(pm
->prefix
) = '\0';
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
;
248 strncpy(pm
->indev_name
, in
->name
, sizeof(pm
->indev_name
));
250 pm
->indev_name
[0] = '\0';
253 strncpy(pm
->outdev_name
, out
->name
, sizeof(pm
->outdev_name
));
255 pm
->outdev_name
[0] = '\0';
257 /* copy_len <= skb->len, so can't fail. */
258 if (skb_copy_bits(skb
, 0, pm
->payload
, copy_len
) < 0)
261 /* check if we are building multi-part messages */
263 ub
->lastnlh
->nlmsg_flags
|= NLM_F_MULTI
;
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
);
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
;
281 spin_unlock_bh(&ulog_lock
);
286 PRINTR("ipt_ULOG: error during NLMSG_PUT\n");
289 PRINTR("ipt_ULOG: Error building netlink message\n");
291 spin_unlock_bh(&ulog_lock
);
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
)
300 struct ipt_ulog_info
*loginfo
= (struct ipt_ulog_info
*) targinfo
;
302 ipt_ulog_packet(hooknum
, *pskb
, in
, out
, loginfo
, NULL
);
307 static void ipt_logfn(unsigned int pf
,
308 unsigned int hooknum
,
309 const struct sk_buff
*skb
,
310 const struct net_device
*in
,
311 const struct net_device
*out
,
312 const struct nf_loginfo
*li
,
315 struct ipt_ulog_info loginfo
;
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';
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
));
329 ipt_ulog_packet(hooknum
, skb
, in
, out
, &loginfo
, prefix
);
332 static int ipt_ulog_checkentry(const char *tablename
,
333 const struct ipt_entry
*e
,
335 unsigned int targinfosize
,
336 unsigned int hookmask
)
338 struct ipt_ulog_info
*loginfo
= (struct ipt_ulog_info
*) targinfo
;
340 if (targinfosize
!= IPT_ALIGN(sizeof(struct ipt_ulog_info
))) {
341 DEBUGP("ipt_ULOG: targinfosize %u != 0\n", targinfosize
);
345 if (loginfo
->prefix
[sizeof(loginfo
->prefix
) - 1] != '\0') {
346 DEBUGP("ipt_ULOG: prefix term %i\n",
347 loginfo
->prefix
[sizeof(loginfo
->prefix
) - 1]);
351 if (loginfo
->qthreshold
> ULOG_MAX_QLEN
) {
352 DEBUGP("ipt_ULOG: queue threshold %i > MAX_QLEN\n",
353 loginfo
->qthreshold
);
360 static struct ipt_target ipt_ulog_reg
= {
362 .target
= ipt_ulog_target
,
363 .checkentry
= ipt_ulog_checkentry
,
367 static struct nf_logger ipt_ulog_logger
= {
373 static int __init
init(void)
377 DEBUGP("ipt_ULOG: init module\n");
379 if (nlbufsiz
>= 128*1024) {
380 printk("Netlink buffer has to be <= 128kB\n");
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
;
391 nflognl
= netlink_kernel_create(NETLINK_NFLOG
, NULL
, THIS_MODULE
);
395 if (ipt_register_target(&ipt_ulog_reg
) != 0) {
396 sock_release(nflognl
->sk_socket
);
400 nf_log_register(PF_INET
, &ipt_ulog_logger
);
405 static void __exit
fini(void)
410 DEBUGP("ipt_ULOG: cleanup_module\n");
413 nf_log_unregister_logger(&ipt_ulog_logger
);
414 ipt_unregister_target(&ipt_ulog_reg
);
415 sock_release(nflognl
->sk_socket
);
417 /* remove pending timers and free allocated skb's */
418 for (i
= 0; i
< ULOG_MAXNLGROUPS
; i
++) {
419 ub
= &ulog_buffers
[i
];
420 if (timer_pending(&ub
->timer
)) {
421 DEBUGP("timer was pending, deleting\n");
422 del_timer(&ub
->timer
);