2 * netfilter module for userspace bridged Ethernet frames logging daemons
5 * Bart De Schuymer <bdschuym@pandora.be>
6 * Harald Welte <laforge@netfilter.org>
10 * Based on ipt_ULOG.c, which is
11 * (C) 2000-2002 by Harald Welte <laforge@netfilter.org>
13 * This module accepts two parameters:
16 * The parameter specifies how big the buffer for each netlink multicast
17 * group is. e.g. If you say nlbufsiz=8192, up to eight kb of packets will
18 * get accumulated in the kernel until they are sent to userspace. It is
19 * NOT possible to allocate more than 128kB, and it is strongly discouraged,
20 * because atomically allocating 128kB inside the network rx softirq is not
21 * reliable. Please also keep in mind that this buffer size is allocated for
22 * each nlgroup you are using, so the total kernel memory usage increases
26 * Specify, after how many hundredths of a second the queue should be
27 * flushed even if it is not full yet.
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31 #include <linux/module.h>
32 #include <linux/slab.h>
33 #include <linux/spinlock.h>
34 #include <linux/socket.h>
35 #include <linux/skbuff.h>
36 #include <linux/kernel.h>
37 #include <linux/timer.h>
38 #include <linux/netlink.h>
39 #include <linux/netdevice.h>
40 #include <linux/netfilter/x_tables.h>
41 #include <linux/netfilter_bridge/ebtables.h>
42 #include <linux/netfilter_bridge/ebt_ulog.h>
43 #include <net/netfilter/nf_log.h>
45 #include "../br_private.h"
47 static unsigned int nlbufsiz
= NLMSG_GOODSIZE
;
48 module_param(nlbufsiz
, uint
, 0600);
49 MODULE_PARM_DESC(nlbufsiz
, "netlink buffer size (number of bytes) "
50 "(defaults to 4096)");
52 static unsigned int flushtimeout
= 10;
53 module_param(flushtimeout
, uint
, 0600);
54 MODULE_PARM_DESC(flushtimeout
, "buffer flush timeout (hundredths ofa second) "
58 unsigned int qlen
; /* number of nlmsgs' in the skb */
59 struct nlmsghdr
*lastnlh
; /* netlink header of last msg in skb */
60 struct sk_buff
*skb
; /* the pre-allocated skb */
61 struct timer_list timer
; /* the timer function */
62 spinlock_t lock
; /* the per-queue lock */
65 static ebt_ulog_buff_t ulog_buffers
[EBT_ULOG_MAXNLGROUPS
];
66 static struct sock
*ebtulognl
;
68 /* send one ulog_buff_t to userspace */
69 static void ulog_send(unsigned int nlgroup
)
71 ebt_ulog_buff_t
*ub
= &ulog_buffers
[nlgroup
];
73 if (timer_pending(&ub
->timer
))
74 del_timer(&ub
->timer
);
79 /* last nlmsg needs NLMSG_DONE */
81 ub
->lastnlh
->nlmsg_type
= NLMSG_DONE
;
83 NETLINK_CB(ub
->skb
).dst_group
= nlgroup
+ 1;
84 netlink_broadcast(ebtulognl
, ub
->skb
, 0, nlgroup
+ 1, GFP_ATOMIC
);
90 /* timer function to flush queue in flushtimeout time */
91 static void ulog_timer(unsigned long data
)
93 spin_lock_bh(&ulog_buffers
[data
].lock
);
94 if (ulog_buffers
[data
].skb
)
96 spin_unlock_bh(&ulog_buffers
[data
].lock
);
99 static struct sk_buff
*ulog_alloc_skb(unsigned int size
)
104 n
= max(size
, nlbufsiz
);
105 skb
= alloc_skb(n
, GFP_ATOMIC
);
107 pr_debug("cannot alloc whole buffer of size %ub!\n", n
);
109 /* try to allocate only as much as we need for
111 skb
= alloc_skb(size
, GFP_ATOMIC
);
113 pr_debug("cannot even allocate "
114 "buffer of size %ub\n", size
);
121 static void ebt_ulog_packet(unsigned int hooknr
, const struct sk_buff
*skb
,
122 const struct net_device
*in
, const struct net_device
*out
,
123 const struct ebt_ulog_info
*uloginfo
, const char *prefix
)
125 ebt_ulog_packet_msg_t
*pm
;
126 size_t size
, copy_len
;
127 struct nlmsghdr
*nlh
;
128 unsigned int group
= uloginfo
->nlgroup
;
129 ebt_ulog_buff_t
*ub
= &ulog_buffers
[group
];
130 spinlock_t
*lock
= &ub
->lock
;
133 if ((uloginfo
->cprange
== 0) ||
134 (uloginfo
->cprange
> skb
->len
+ ETH_HLEN
))
135 copy_len
= skb
->len
+ ETH_HLEN
;
137 copy_len
= uloginfo
->cprange
;
139 size
= NLMSG_SPACE(sizeof(*pm
) + copy_len
);
140 if (size
> nlbufsiz
) {
141 pr_debug("Size %Zd needed, but nlbufsiz=%d\n", size
, nlbufsiz
);
148 if (!(ub
->skb
= ulog_alloc_skb(size
)))
150 } else if (size
> skb_tailroom(ub
->skb
)) {
153 if (!(ub
->skb
= ulog_alloc_skb(size
)))
157 nlh
= NLMSG_PUT(ub
->skb
, 0, ub
->qlen
, 0,
158 size
- NLMSG_ALIGN(sizeof(*nlh
)));
161 pm
= NLMSG_DATA(nlh
);
163 /* Fill in the ulog data */
164 pm
->version
= EBT_ULOG_VERSION
;
165 kt
= ktime_get_real();
166 pm
->stamp
= ktime_to_timeval(kt
);
168 ub
->skb
->tstamp
= kt
;
169 pm
->data_len
= copy_len
;
170 pm
->mark
= skb
->mark
;
172 if (uloginfo
->prefix
!= NULL
)
173 strcpy(pm
->prefix
, uloginfo
->prefix
);
175 *(pm
->prefix
) = '\0';
178 strcpy(pm
->physindev
, in
->name
);
179 /* If in isn't a bridge, then physindev==indev */
180 if (br_port_exists(in
))
181 /* rcu_read_lock()ed by nf_hook_slow */
182 strcpy(pm
->indev
, br_port_get_rcu(in
)->br
->dev
->name
);
184 strcpy(pm
->indev
, in
->name
);
186 pm
->indev
[0] = pm
->physindev
[0] = '\0';
189 /* If out exists, then out is a bridge port */
190 strcpy(pm
->physoutdev
, out
->name
);
191 /* rcu_read_lock()ed by nf_hook_slow */
192 strcpy(pm
->outdev
, br_port_get_rcu(out
)->br
->dev
->name
);
194 pm
->outdev
[0] = pm
->physoutdev
[0] = '\0';
196 if (skb_copy_bits(skb
, -ETH_HLEN
, pm
->data
, copy_len
) < 0)
200 ub
->lastnlh
->nlmsg_flags
|= NLM_F_MULTI
;
204 if (ub
->qlen
>= uloginfo
->qthreshold
)
206 else if (!timer_pending(&ub
->timer
)) {
207 ub
->timer
.expires
= jiffies
+ flushtimeout
* HZ
/ 100;
208 add_timer(&ub
->timer
);
212 spin_unlock_bh(lock
);
217 pr_debug("error during NLMSG_PUT. This should "
218 "not happen, please report to author.\n");
223 /* this function is registered with the netfilter core */
224 static void ebt_log_packet(u_int8_t pf
, unsigned int hooknum
,
225 const struct sk_buff
*skb
, const struct net_device
*in
,
226 const struct net_device
*out
, const struct nf_loginfo
*li
,
229 struct ebt_ulog_info loginfo
;
231 if (!li
|| li
->type
!= NF_LOG_TYPE_ULOG
) {
232 loginfo
.nlgroup
= EBT_ULOG_DEFAULT_NLGROUP
;
234 loginfo
.qthreshold
= EBT_ULOG_DEFAULT_QTHRESHOLD
;
235 loginfo
.prefix
[0] = '\0';
237 loginfo
.nlgroup
= li
->u
.ulog
.group
;
238 loginfo
.cprange
= li
->u
.ulog
.copy_len
;
239 loginfo
.qthreshold
= li
->u
.ulog
.qthreshold
;
240 strlcpy(loginfo
.prefix
, prefix
, sizeof(loginfo
.prefix
));
243 ebt_ulog_packet(hooknum
, skb
, in
, out
, &loginfo
, prefix
);
247 ebt_ulog_tg(struct sk_buff
*skb
, const struct xt_action_param
*par
)
249 ebt_ulog_packet(par
->hooknum
, skb
, par
->in
, par
->out
,
250 par
->targinfo
, NULL
);
254 static int ebt_ulog_tg_check(const struct xt_tgchk_param
*par
)
256 struct ebt_ulog_info
*uloginfo
= par
->targinfo
;
258 if (uloginfo
->nlgroup
> 31)
261 uloginfo
->prefix
[EBT_ULOG_PREFIX_LEN
- 1] = '\0';
263 if (uloginfo
->qthreshold
> EBT_ULOG_MAX_QLEN
)
264 uloginfo
->qthreshold
= EBT_ULOG_MAX_QLEN
;
269 static struct xt_target ebt_ulog_tg_reg __read_mostly
= {
272 .family
= NFPROTO_BRIDGE
,
273 .target
= ebt_ulog_tg
,
274 .checkentry
= ebt_ulog_tg_check
,
275 .targetsize
= sizeof(struct ebt_ulog_info
),
279 static struct nf_logger ebt_ulog_logger __read_mostly
= {
281 .logfn
= &ebt_log_packet
,
285 static int __init
ebt_ulog_init(void)
290 if (nlbufsiz
>= 128*1024) {
291 pr_warning("Netlink buffer has to be <= 128kB,"
292 " please try a smaller nlbufsiz parameter.\n");
296 /* initialize ulog_buffers */
297 for (i
= 0; i
< EBT_ULOG_MAXNLGROUPS
; i
++) {
298 setup_timer(&ulog_buffers
[i
].timer
, ulog_timer
, i
);
299 spin_lock_init(&ulog_buffers
[i
].lock
);
302 ebtulognl
= netlink_kernel_create(&init_net
, NETLINK_NFLOG
,
303 EBT_ULOG_MAXNLGROUPS
, NULL
, NULL
,
307 else if ((ret
= xt_register_target(&ebt_ulog_tg_reg
)) != 0)
308 netlink_kernel_release(ebtulognl
);
311 nf_log_register(NFPROTO_BRIDGE
, &ebt_ulog_logger
);
316 static void __exit
ebt_ulog_fini(void)
321 nf_log_unregister(&ebt_ulog_logger
);
322 xt_unregister_target(&ebt_ulog_tg_reg
);
323 for (i
= 0; i
< EBT_ULOG_MAXNLGROUPS
; i
++) {
324 ub
= &ulog_buffers
[i
];
325 if (timer_pending(&ub
->timer
))
326 del_timer(&ub
->timer
);
327 spin_lock_bh(&ub
->lock
);
332 spin_unlock_bh(&ub
->lock
);
334 netlink_kernel_release(ebtulognl
);
337 module_init(ebt_ulog_init
);
338 module_exit(ebt_ulog_fini
);
339 MODULE_LICENSE("GPL");
340 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
341 MODULE_DESCRIPTION("Ebtables: Packet logging to netlink using ULOG");