2 * netfilter module for userspace bridged Ethernet frames logging daemons
5 * Bart De Schuymer <bdschuym@pandora.be>
9 * Based on ipt_ULOG.c, which is
10 * (C) 2000-2002 by Harald Welte <laforge@netfilter.org>
12 * This module accepts two parameters:
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
25 * Specify, after how many hundredths of a second the queue should be
26 * flushed even if it is not full yet.
30 #include <linux/module.h>
31 #include <linux/config.h>
32 #include <linux/spinlock.h>
33 #include <linux/socket.h>
34 #include <linux/skbuff.h>
35 #include <linux/kernel.h>
36 #include <linux/timer.h>
37 #include <linux/netlink.h>
38 #include <linux/netdevice.h>
39 #include <linux/module.h>
40 #include <linux/netfilter_bridge/ebtables.h>
41 #include <linux/netfilter_bridge/ebt_ulog.h>
43 #include "../br_private.h"
45 #define PRINTR(format, args...) do { if (net_ratelimit()) \
46 printk(format , ## args); } while (0)
48 static unsigned int nlbufsiz
= 4096;
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 ebt_ulog_buff_t ulog_buffers
[EBT_ULOG_MAXNLGROUPS
];
67 static struct sock
*ebtulognl
;
69 /* send one ulog_buff_t to userspace */
70 static void ulog_send(unsigned int nlgroup
)
72 ebt_ulog_buff_t
*ub
= &ulog_buffers
[nlgroup
];
74 if (timer_pending(&ub
->timer
))
75 del_timer(&ub
->timer
);
77 /* last nlmsg needs NLMSG_DONE */
79 ub
->lastnlh
->nlmsg_type
= NLMSG_DONE
;
81 NETLINK_CB(ub
->skb
).dst_group
= nlgroup
+ 1;
82 netlink_broadcast(ebtulognl
, ub
->skb
, 0, nlgroup
+ 1, GFP_ATOMIC
);
88 /* timer function to flush queue in flushtimeout time */
89 static void ulog_timer(unsigned long data
)
91 spin_lock_bh(&ulog_buffers
[data
].lock
);
92 if (ulog_buffers
[data
].skb
)
94 spin_unlock_bh(&ulog_buffers
[data
].lock
);
97 static struct sk_buff
*ulog_alloc_skb(unsigned int size
)
101 skb
= alloc_skb(nlbufsiz
, GFP_ATOMIC
);
103 PRINTR(KERN_ERR
"ebt_ulog: can't alloc whole buffer "
104 "of size %ub!\n", nlbufsiz
);
105 if (size
< nlbufsiz
) {
106 /* try to allocate only as much as we need for
108 skb
= alloc_skb(size
, GFP_ATOMIC
);
110 PRINTR(KERN_ERR
"ebt_ulog: can't even allocate "
111 "buffer of size %ub\n", size
);
118 static void ebt_ulog(const struct sk_buff
*skb
, unsigned int hooknr
,
119 const struct net_device
*in
, const struct net_device
*out
,
120 const void *data
, unsigned int datalen
)
122 ebt_ulog_packet_msg_t
*pm
;
123 size_t size
, copy_len
;
124 struct nlmsghdr
*nlh
;
125 struct ebt_ulog_info
*uloginfo
= (struct ebt_ulog_info
*)data
;
126 unsigned int group
= uloginfo
->nlgroup
;
127 ebt_ulog_buff_t
*ub
= &ulog_buffers
[group
];
128 spinlock_t
*lock
= &ub
->lock
;
130 if ((uloginfo
->cprange
== 0) ||
131 (uloginfo
->cprange
> skb
->len
+ ETH_HLEN
))
132 copy_len
= skb
->len
+ ETH_HLEN
;
134 copy_len
= uloginfo
->cprange
;
136 size
= NLMSG_SPACE(sizeof(*pm
) + copy_len
);
137 if (size
> nlbufsiz
) {
138 PRINTR("ebt_ulog: Size %Zd needed, but nlbufsiz=%d\n",
146 if (!(ub
->skb
= ulog_alloc_skb(size
)))
148 } else if (size
> skb_tailroom(ub
->skb
)) {
151 if (!(ub
->skb
= ulog_alloc_skb(size
)))
155 nlh
= NLMSG_PUT(ub
->skb
, 0, ub
->qlen
, 0,
156 size
- NLMSG_ALIGN(sizeof(*nlh
)));
159 pm
= NLMSG_DATA(nlh
);
161 /* Fill in the ulog data */
162 pm
->version
= EBT_ULOG_VERSION
;
163 do_gettimeofday(&pm
->stamp
);
165 skb_set_timestamp(ub
->skb
, &pm
->stamp
);
166 pm
->data_len
= copy_len
;
167 pm
->mark
= skb
->nfmark
;
169 if (uloginfo
->prefix
!= NULL
)
170 strcpy(pm
->prefix
, uloginfo
->prefix
);
172 *(pm
->prefix
) = '\0';
175 strcpy(pm
->physindev
, in
->name
);
176 /* If in isn't a bridge, then physindev==indev */
178 strcpy(pm
->indev
, in
->br_port
->br
->dev
->name
);
180 strcpy(pm
->indev
, in
->name
);
182 pm
->indev
[0] = pm
->physindev
[0] = '\0';
185 /* If out exists, then out is a bridge port */
186 strcpy(pm
->physoutdev
, out
->name
);
187 strcpy(pm
->outdev
, out
->br_port
->br
->dev
->name
);
189 pm
->outdev
[0] = pm
->physoutdev
[0] = '\0';
191 if (skb_copy_bits(skb
, -ETH_HLEN
, pm
->data
, copy_len
) < 0)
195 ub
->lastnlh
->nlmsg_flags
|= NLM_F_MULTI
;
199 if (ub
->qlen
>= uloginfo
->qthreshold
)
201 else if (!timer_pending(&ub
->timer
)) {
202 ub
->timer
.expires
= jiffies
+ flushtimeout
* HZ
/ 100;
203 add_timer(&ub
->timer
);
207 spin_unlock_bh(lock
);
212 printk(KERN_CRIT
"ebt_ulog: error during NLMSG_PUT. This should "
213 "not happen, please report to author.\n");
219 static int ebt_ulog_check(const char *tablename
, unsigned int hookmask
,
220 const struct ebt_entry
*e
, void *data
, unsigned int datalen
)
222 struct ebt_ulog_info
*uloginfo
= (struct ebt_ulog_info
*)data
;
224 if (datalen
!= EBT_ALIGN(sizeof(struct ebt_ulog_info
)) ||
225 uloginfo
->nlgroup
> 31)
228 uloginfo
->prefix
[EBT_ULOG_PREFIX_LEN
- 1] = '\0';
230 if (uloginfo
->qthreshold
> EBT_ULOG_MAX_QLEN
)
231 uloginfo
->qthreshold
= EBT_ULOG_MAX_QLEN
;
236 static struct ebt_watcher ulog
= {
237 .name
= EBT_ULOG_WATCHER
,
239 .check
= ebt_ulog_check
,
243 static int __init
init(void)
247 if (nlbufsiz
>= 128*1024) {
248 printk(KERN_NOTICE
"ebt_ulog: Netlink buffer has to be <= 128kB,"
249 " please try a smaller nlbufsiz parameter.\n");
253 /* initialize ulog_buffers */
254 for (i
= 0; i
< EBT_ULOG_MAXNLGROUPS
; i
++) {
255 init_timer(&ulog_buffers
[i
].timer
);
256 ulog_buffers
[i
].timer
.function
= ulog_timer
;
257 ulog_buffers
[i
].timer
.data
= i
;
258 spin_lock_init(&ulog_buffers
[i
].lock
);
261 ebtulognl
= netlink_kernel_create(NETLINK_NFLOG
, NULL
, THIS_MODULE
);
264 else if ((ret
= ebt_register_watcher(&ulog
)))
265 sock_release(ebtulognl
->sk_socket
);
270 static void __exit
fini(void)
275 ebt_unregister_watcher(&ulog
);
276 for (i
= 0; i
< EBT_ULOG_MAXNLGROUPS
; i
++) {
277 ub
= &ulog_buffers
[i
];
278 if (timer_pending(&ub
->timer
))
279 del_timer(&ub
->timer
);
280 spin_lock_bh(&ub
->lock
);
285 spin_unlock_bh(&ub
->lock
);
287 sock_release(ebtulognl
->sk_socket
);
292 MODULE_LICENSE("GPL");
293 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
294 MODULE_DESCRIPTION("ebtables userspace logging module for bridged Ethernet"