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 <net/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>
44 #include <net/netns/generic.h>
46 #include "../br_private.h"
48 static unsigned int nlbufsiz
= NLMSG_GOODSIZE
;
49 module_param(nlbufsiz
, uint
, 0600);
50 MODULE_PARM_DESC(nlbufsiz
, "netlink buffer size (number of bytes) "
51 "(defaults to 4096)");
53 static unsigned int flushtimeout
= 10;
54 module_param(flushtimeout
, uint
, 0600);
55 MODULE_PARM_DESC(flushtimeout
, "buffer flush timeout (hundredths ofa second) "
59 unsigned int qlen
; /* number of nlmsgs' in the skb */
60 struct nlmsghdr
*lastnlh
; /* netlink header of last msg in skb */
61 struct sk_buff
*skb
; /* the pre-allocated skb */
62 struct timer_list timer
; /* the timer function */
63 spinlock_t lock
; /* the per-queue lock */
66 static int ebt_ulog_net_id __read_mostly
;
68 unsigned int nlgroup
[EBT_ULOG_MAXNLGROUPS
];
69 ebt_ulog_buff_t ulog_buffers
[EBT_ULOG_MAXNLGROUPS
];
70 struct sock
*ebtulognl
;
73 static struct ebt_ulog_net
*ebt_ulog_pernet(struct net
*net
)
75 return net_generic(net
, ebt_ulog_net_id
);
78 /* send one ulog_buff_t to userspace */
79 static void ulog_send(struct ebt_ulog_net
*ebt
, unsigned int nlgroup
)
81 ebt_ulog_buff_t
*ub
= &ebt
->ulog_buffers
[nlgroup
];
83 del_timer(&ub
->timer
);
88 /* last nlmsg needs NLMSG_DONE */
90 ub
->lastnlh
->nlmsg_type
= NLMSG_DONE
;
92 NETLINK_CB(ub
->skb
).dst_group
= nlgroup
+ 1;
93 netlink_broadcast(ebt
->ebtulognl
, ub
->skb
, 0, nlgroup
+ 1, GFP_ATOMIC
);
99 /* timer function to flush queue in flushtimeout time */
100 static void ulog_timer(unsigned long data
)
102 struct ebt_ulog_net
*ebt
= container_of((void *)data
,
104 nlgroup
[*(unsigned int *)data
]);
106 ebt_ulog_buff_t
*ub
= &ebt
->ulog_buffers
[*(unsigned int *)data
];
107 spin_lock_bh(&ub
->lock
);
109 ulog_send(ebt
, *(unsigned int *)data
);
110 spin_unlock_bh(&ub
->lock
);
113 static struct sk_buff
*ulog_alloc_skb(unsigned int size
)
118 n
= max(size
, nlbufsiz
);
119 skb
= alloc_skb(n
, GFP_ATOMIC
| __GFP_NOWARN
);
122 /* try to allocate only as much as we need for
124 skb
= alloc_skb(size
, GFP_ATOMIC
);
126 pr_debug("cannot even allocate buffer of size %ub\n",
134 static void ebt_ulog_packet(unsigned int hooknr
, const struct sk_buff
*skb
,
135 const struct net_device
*in
, const struct net_device
*out
,
136 const struct ebt_ulog_info
*uloginfo
, const char *prefix
)
138 ebt_ulog_packet_msg_t
*pm
;
139 size_t size
, copy_len
;
140 struct nlmsghdr
*nlh
;
141 struct net
*net
= dev_net(in
? in
: out
);
142 struct ebt_ulog_net
*ebt
= ebt_ulog_pernet(net
);
143 unsigned int group
= uloginfo
->nlgroup
;
144 ebt_ulog_buff_t
*ub
= &ebt
->ulog_buffers
[group
];
145 spinlock_t
*lock
= &ub
->lock
;
148 if ((uloginfo
->cprange
== 0) ||
149 (uloginfo
->cprange
> skb
->len
+ ETH_HLEN
))
150 copy_len
= skb
->len
+ ETH_HLEN
;
152 copy_len
= uloginfo
->cprange
;
154 size
= nlmsg_total_size(sizeof(*pm
) + copy_len
);
155 if (size
> nlbufsiz
) {
156 pr_debug("Size %Zd needed, but nlbufsiz=%d\n", size
, nlbufsiz
);
163 if (!(ub
->skb
= ulog_alloc_skb(size
)))
165 } else if (size
> skb_tailroom(ub
->skb
)) {
166 ulog_send(ebt
, group
);
168 if (!(ub
->skb
= ulog_alloc_skb(size
)))
172 nlh
= nlmsg_put(ub
->skb
, 0, ub
->qlen
, 0,
173 size
- NLMSG_ALIGN(sizeof(*nlh
)), 0);
181 pm
= nlmsg_data(nlh
);
183 /* Fill in the ulog data */
184 pm
->version
= EBT_ULOG_VERSION
;
185 kt
= ktime_get_real();
186 pm
->stamp
= ktime_to_timeval(kt
);
188 ub
->skb
->tstamp
= kt
;
189 pm
->data_len
= copy_len
;
190 pm
->mark
= skb
->mark
;
192 if (uloginfo
->prefix
!= NULL
)
193 strcpy(pm
->prefix
, uloginfo
->prefix
);
195 *(pm
->prefix
) = '\0';
198 strcpy(pm
->physindev
, in
->name
);
199 /* If in isn't a bridge, then physindev==indev */
200 if (br_port_exists(in
))
201 /* rcu_read_lock()ed by nf_hook_slow */
202 strcpy(pm
->indev
, br_port_get_rcu(in
)->br
->dev
->name
);
204 strcpy(pm
->indev
, in
->name
);
206 pm
->indev
[0] = pm
->physindev
[0] = '\0';
209 /* If out exists, then out is a bridge port */
210 strcpy(pm
->physoutdev
, out
->name
);
211 /* rcu_read_lock()ed by nf_hook_slow */
212 strcpy(pm
->outdev
, br_port_get_rcu(out
)->br
->dev
->name
);
214 pm
->outdev
[0] = pm
->physoutdev
[0] = '\0';
216 if (skb_copy_bits(skb
, -ETH_HLEN
, pm
->data
, copy_len
) < 0)
220 ub
->lastnlh
->nlmsg_flags
|= NLM_F_MULTI
;
224 if (ub
->qlen
>= uloginfo
->qthreshold
)
225 ulog_send(ebt
, group
);
226 else if (!timer_pending(&ub
->timer
)) {
227 ub
->timer
.expires
= jiffies
+ flushtimeout
* HZ
/ 100;
228 add_timer(&ub
->timer
);
232 spin_unlock_bh(lock
);
235 /* this function is registered with the netfilter core */
236 static void ebt_log_packet(u_int8_t pf
, unsigned int hooknum
,
237 const struct sk_buff
*skb
, const struct net_device
*in
,
238 const struct net_device
*out
, const struct nf_loginfo
*li
,
241 struct ebt_ulog_info loginfo
;
243 if (!li
|| li
->type
!= NF_LOG_TYPE_ULOG
) {
244 loginfo
.nlgroup
= EBT_ULOG_DEFAULT_NLGROUP
;
246 loginfo
.qthreshold
= EBT_ULOG_DEFAULT_QTHRESHOLD
;
247 loginfo
.prefix
[0] = '\0';
249 loginfo
.nlgroup
= li
->u
.ulog
.group
;
250 loginfo
.cprange
= li
->u
.ulog
.copy_len
;
251 loginfo
.qthreshold
= li
->u
.ulog
.qthreshold
;
252 strlcpy(loginfo
.prefix
, prefix
, sizeof(loginfo
.prefix
));
255 ebt_ulog_packet(hooknum
, skb
, in
, out
, &loginfo
, prefix
);
259 ebt_ulog_tg(struct sk_buff
*skb
, const struct xt_action_param
*par
)
261 ebt_ulog_packet(par
->hooknum
, skb
, par
->in
, par
->out
,
262 par
->targinfo
, NULL
);
266 static int ebt_ulog_tg_check(const struct xt_tgchk_param
*par
)
268 struct ebt_ulog_info
*uloginfo
= par
->targinfo
;
270 if (uloginfo
->nlgroup
> 31)
273 uloginfo
->prefix
[EBT_ULOG_PREFIX_LEN
- 1] = '\0';
275 if (uloginfo
->qthreshold
> EBT_ULOG_MAX_QLEN
)
276 uloginfo
->qthreshold
= EBT_ULOG_MAX_QLEN
;
281 static struct xt_target ebt_ulog_tg_reg __read_mostly
= {
284 .family
= NFPROTO_BRIDGE
,
285 .target
= ebt_ulog_tg
,
286 .checkentry
= ebt_ulog_tg_check
,
287 .targetsize
= sizeof(struct ebt_ulog_info
),
291 static struct nf_logger ebt_ulog_logger __read_mostly
= {
293 .logfn
= &ebt_log_packet
,
297 static int __net_init
ebt_ulog_net_init(struct net
*net
)
300 struct ebt_ulog_net
*ebt
= ebt_ulog_pernet(net
);
302 struct netlink_kernel_cfg cfg
= {
303 .groups
= EBT_ULOG_MAXNLGROUPS
,
306 /* initialize ulog_buffers */
307 for (i
= 0; i
< EBT_ULOG_MAXNLGROUPS
; i
++) {
309 setup_timer(&ebt
->ulog_buffers
[i
].timer
, ulog_timer
,
310 (unsigned long)&ebt
->nlgroup
[i
]);
311 spin_lock_init(&ebt
->ulog_buffers
[i
].lock
);
314 ebt
->ebtulognl
= netlink_kernel_create(net
, NETLINK_NFLOG
, &cfg
);
318 nf_log_set(net
, NFPROTO_BRIDGE
, &ebt_ulog_logger
);
322 static void __net_exit
ebt_ulog_net_fini(struct net
*net
)
325 struct ebt_ulog_net
*ebt
= ebt_ulog_pernet(net
);
327 nf_log_unset(net
, &ebt_ulog_logger
);
328 for (i
= 0; i
< EBT_ULOG_MAXNLGROUPS
; i
++) {
329 ebt_ulog_buff_t
*ub
= &ebt
->ulog_buffers
[i
];
330 del_timer(&ub
->timer
);
337 netlink_kernel_release(ebt
->ebtulognl
);
340 static struct pernet_operations ebt_ulog_net_ops
= {
341 .init
= ebt_ulog_net_init
,
342 .exit
= ebt_ulog_net_fini
,
343 .id
= &ebt_ulog_net_id
,
344 .size
= sizeof(struct ebt_ulog_net
),
347 static int __init
ebt_ulog_init(void)
351 if (nlbufsiz
>= 128*1024) {
352 pr_warn("Netlink buffer has to be <= 128kB,"
353 "please try a smaller nlbufsiz parameter.\n");
357 ret
= register_pernet_subsys(&ebt_ulog_net_ops
);
361 ret
= xt_register_target(&ebt_ulog_tg_reg
);
365 nf_log_register(NFPROTO_BRIDGE
, &ebt_ulog_logger
);
370 unregister_pernet_subsys(&ebt_ulog_net_ops
);
375 static void __exit
ebt_ulog_fini(void)
377 nf_log_unregister(&ebt_ulog_logger
);
378 xt_unregister_target(&ebt_ulog_tg_reg
);
379 unregister_pernet_subsys(&ebt_ulog_net_ops
);
382 module_init(ebt_ulog_init
);
383 module_exit(ebt_ulog_fini
);
384 MODULE_LICENSE("GPL");
385 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
386 MODULE_DESCRIPTION("Ebtables: Packet logging to netlink using ULOG");