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.
31 #include <linux/module.h>
32 #include <linux/config.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/module.h>
41 #include <linux/netfilter_bridge/ebtables.h>
42 #include <linux/netfilter_bridge/ebt_ulog.h>
44 #include "../br_private.h"
46 #define PRINTR(format, args...) do { if (net_ratelimit()) \
47 printk(format , ## args); } while (0)
49 static unsigned int nlbufsiz = NLMSG_GOODSIZE;
50 module_param(nlbufsiz, uint, 0600);
51 MODULE_PARM_DESC(nlbufsiz, "netlink buffer size (number of bytes) "
52 "(defaults to 4096)");
54 static unsigned int flushtimeout = 10;
55 module_param(flushtimeout, uint, 0600);
56 MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths ofa second) "
60 unsigned int qlen; /* number of nlmsgs' in the skb */
61 struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */
62 struct sk_buff *skb; /* the pre-allocated skb */
63 struct timer_list timer; /* the timer function */
64 spinlock_t lock; /* the per-queue lock */
67 static ebt_ulog_buff_t ulog_buffers[EBT_ULOG_MAXNLGROUPS];
68 static struct sock *ebtulognl;
70 /* send one ulog_buff_t to userspace */
71 static void ulog_send(unsigned int nlgroup)
73 ebt_ulog_buff_t *ub = &ulog_buffers[nlgroup];
75 if (timer_pending(&ub->timer))
76 del_timer(&ub->timer);
78 /* last nlmsg needs NLMSG_DONE */
80 ub->lastnlh->nlmsg_type = NLMSG_DONE;
82 NETLINK_CB(ub->skb).dst_group = nlgroup + 1;
83 netlink_broadcast(ebtulognl, ub->skb, 0, nlgroup + 1, GFP_ATOMIC);
89 /* timer function to flush queue in flushtimeout time */
90 static void ulog_timer(unsigned long data)
92 spin_lock_bh(&ulog_buffers[data].lock);
93 if (ulog_buffers[data].skb)
95 spin_unlock_bh(&ulog_buffers[data].lock);
98 static struct sk_buff *ulog_alloc_skb(unsigned int size)
103 n = max(size, nlbufsiz);
104 skb = alloc_skb(n, GFP_ATOMIC);
106 PRINTR(KERN_ERR "ebt_ulog: can't alloc whole buffer "
107 "of size %ub!\n", n);
109 /* try to allocate only as much as we need for
111 skb = alloc_skb(size, GFP_ATOMIC);
113 PRINTR(KERN_ERR "ebt_ulog: can't 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;
132 if ((uloginfo->cprange == 0) ||
133 (uloginfo->cprange > skb->len + ETH_HLEN))
134 copy_len = skb->len + ETH_HLEN;
136 copy_len = uloginfo->cprange;
138 size = NLMSG_SPACE(sizeof(*pm) + copy_len);
139 if (size > nlbufsiz) {
140 PRINTR("ebt_ulog: Size %Zd needed, but nlbufsiz=%d\n",
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 do_gettimeofday(&pm->stamp);
167 skb_set_timestamp(ub->skb, &pm->stamp);
168 pm->data_len = copy_len;
169 pm->mark = skb->nfmark;
171 if (uloginfo->prefix != NULL)
172 strcpy(pm->prefix, uloginfo->prefix);
174 *(pm->prefix) = '\0';
177 strcpy(pm->physindev, in->name);
178 /* If in isn't a bridge, then physindev==indev */
180 strcpy(pm->indev, in->br_port->br->dev->name);
182 strcpy(pm->indev, in->name);
184 pm->indev[0] = pm->physindev[0] = '\0';
187 /* If out exists, then out is a bridge port */
188 strcpy(pm->physoutdev, out->name);
189 strcpy(pm->outdev, out->br_port->br->dev->name);
191 pm->outdev[0] = pm->physoutdev[0] = '\0';
193 if (skb_copy_bits(skb, -ETH_HLEN, pm->data, copy_len) < 0)
197 ub->lastnlh->nlmsg_flags |= NLM_F_MULTI;
201 if (ub->qlen >= uloginfo->qthreshold)
203 else if (!timer_pending(&ub->timer)) {
204 ub->timer.expires = jiffies + flushtimeout * HZ / 100;
205 add_timer(&ub->timer);
209 spin_unlock_bh(lock);
214 printk(KERN_CRIT "ebt_ulog: error during NLMSG_PUT. This should "
215 "not happen, please report to author.\n");
221 /* this function is registered with the netfilter core */
222 static void ebt_log_packet(unsigned int pf, unsigned int hooknum,
223 const struct sk_buff *skb, const struct net_device *in,
224 const struct net_device *out, const struct nf_loginfo *li,
227 struct ebt_ulog_info loginfo;
229 if (!li || li->type != NF_LOG_TYPE_ULOG) {
230 loginfo.nlgroup = EBT_ULOG_DEFAULT_NLGROUP;
232 loginfo.qthreshold = EBT_ULOG_DEFAULT_QTHRESHOLD;
233 loginfo.prefix[0] = '\0';
235 loginfo.nlgroup = li->u.ulog.group;
236 loginfo.cprange = li->u.ulog.copy_len;
237 loginfo.qthreshold = li->u.ulog.qthreshold;
238 strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix));
241 ebt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix);
244 static void ebt_ulog(const struct sk_buff *skb, unsigned int hooknr,
245 const struct net_device *in, const struct net_device *out,
246 const void *data, unsigned int datalen)
248 struct ebt_ulog_info *uloginfo = (struct ebt_ulog_info *)data;
250 ebt_ulog_packet(hooknr, skb, in, out, uloginfo, NULL);
254 static int ebt_ulog_check(const char *tablename, unsigned int hookmask,
255 const struct ebt_entry *e, void *data, unsigned int datalen)
257 struct ebt_ulog_info *uloginfo = (struct ebt_ulog_info *)data;
259 if (datalen != EBT_ALIGN(sizeof(struct ebt_ulog_info)) ||
260 uloginfo->nlgroup > 31)
263 uloginfo->prefix[EBT_ULOG_PREFIX_LEN - 1] = '\0';
265 if (uloginfo->qthreshold > EBT_ULOG_MAX_QLEN)
266 uloginfo->qthreshold = EBT_ULOG_MAX_QLEN;
271 static struct ebt_watcher ulog = {
272 .name = EBT_ULOG_WATCHER,
274 .check = ebt_ulog_check,
278 static struct nf_logger ebt_ulog_logger = {
279 .name = EBT_ULOG_WATCHER,
280 .logfn = &ebt_log_packet,
284 static int __init ebt_ulog_init(void)
288 if (nlbufsiz >= 128*1024) {
289 printk(KERN_NOTICE "ebt_ulog: Netlink buffer has to be <= 128kB,"
290 " please try a smaller nlbufsiz parameter.\n");
294 /* initialize ulog_buffers */
295 for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
296 init_timer(&ulog_buffers[i].timer);
297 ulog_buffers[i].timer.function = ulog_timer;
298 ulog_buffers[i].timer.data = i;
299 spin_lock_init(&ulog_buffers[i].lock);
302 ebtulognl = netlink_kernel_create(NETLINK_NFLOG, EBT_ULOG_MAXNLGROUPS,
306 else if ((ret = ebt_register_watcher(&ulog)))
307 sock_release(ebtulognl->sk_socket);
309 if (nf_log_register(PF_BRIDGE, &ebt_ulog_logger) < 0) {
310 printk(KERN_WARNING "ebt_ulog: not logging via ulog "
311 "since somebody else already registered for PF_BRIDGE\n");
312 /* we cannot make module load fail here, since otherwise
313 * ebtables userspace would abort */
319 static void __exit ebt_ulog_fini(void)
324 nf_log_unregister_logger(&ebt_ulog_logger);
325 ebt_unregister_watcher(&ulog);
326 for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
327 ub = &ulog_buffers[i];
328 if (timer_pending(&ub->timer))
329 del_timer(&ub->timer);
330 spin_lock_bh(&ub->lock);
335 spin_unlock_bh(&ub->lock);
337 sock_release(ebtulognl->sk_socket);
340 module_init(ebt_ulog_init);
341 module_exit(ebt_ulog_fini);
342 MODULE_LICENSE("GPL");
343 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
344 MODULE_DESCRIPTION("ebtables userspace logging module for bridged Ethernet"