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(struct net *net, unsigned int hooknr,
135 const struct sk_buff *skb,
136 const struct net_device *in,
137 const struct net_device *out,
138 const struct ebt_ulog_info *uloginfo,
141 ebt_ulog_packet_msg_t *pm;
142 size_t size, copy_len;
143 struct nlmsghdr *nlh;
144 struct ebt_ulog_net *ebt = ebt_ulog_pernet(net);
145 unsigned int group = uloginfo->nlgroup;
146 ebt_ulog_buff_t *ub = &ebt->ulog_buffers[group];
147 spinlock_t *lock = &ub->lock;
150 if ((uloginfo->cprange == 0) ||
151 (uloginfo->cprange > skb->len + ETH_HLEN))
152 copy_len = skb->len + ETH_HLEN;
154 copy_len = uloginfo->cprange;
156 size = nlmsg_total_size(sizeof(*pm) + copy_len);
157 if (size > nlbufsiz) {
158 pr_debug("Size %Zd needed, but nlbufsiz=%d\n", size, nlbufsiz);
165 if (!(ub->skb = ulog_alloc_skb(size)))
167 } else if (size > skb_tailroom(ub->skb)) {
168 ulog_send(ebt, group);
170 if (!(ub->skb = ulog_alloc_skb(size)))
174 nlh = nlmsg_put(ub->skb, 0, ub->qlen, 0,
175 size - NLMSG_ALIGN(sizeof(*nlh)), 0);
183 pm = nlmsg_data(nlh);
185 /* Fill in the ulog data */
186 pm->version = EBT_ULOG_VERSION;
187 kt = ktime_get_real();
188 pm->stamp = ktime_to_timeval(kt);
190 ub->skb->tstamp = kt;
191 pm->data_len = copy_len;
192 pm->mark = skb->mark;
194 if (uloginfo->prefix != NULL)
195 strcpy(pm->prefix, uloginfo->prefix);
197 *(pm->prefix) = '\0';
200 strcpy(pm->physindev, in->name);
201 /* If in isn't a bridge, then physindev==indev */
202 if (br_port_exists(in))
203 /* rcu_read_lock()ed by nf_hook_slow */
204 strcpy(pm->indev, br_port_get_rcu(in)->br->dev->name);
206 strcpy(pm->indev, in->name);
208 pm->indev[0] = pm->physindev[0] = '\0';
211 /* If out exists, then out is a bridge port */
212 strcpy(pm->physoutdev, out->name);
213 /* rcu_read_lock()ed by nf_hook_slow */
214 strcpy(pm->outdev, br_port_get_rcu(out)->br->dev->name);
216 pm->outdev[0] = pm->physoutdev[0] = '\0';
218 if (skb_copy_bits(skb, -ETH_HLEN, pm->data, copy_len) < 0)
222 ub->lastnlh->nlmsg_flags |= NLM_F_MULTI;
226 if (ub->qlen >= uloginfo->qthreshold)
227 ulog_send(ebt, group);
228 else if (!timer_pending(&ub->timer)) {
229 ub->timer.expires = jiffies + flushtimeout * HZ / 100;
230 add_timer(&ub->timer);
234 spin_unlock_bh(lock);
237 /* this function is registered with the netfilter core */
238 static void ebt_log_packet(struct net *net, u_int8_t pf, unsigned int hooknum,
239 const struct sk_buff *skb, const struct net_device *in,
240 const struct net_device *out, const struct nf_loginfo *li,
243 struct ebt_ulog_info loginfo;
245 if (!li || li->type != NF_LOG_TYPE_ULOG) {
246 loginfo.nlgroup = EBT_ULOG_DEFAULT_NLGROUP;
248 loginfo.qthreshold = EBT_ULOG_DEFAULT_QTHRESHOLD;
249 loginfo.prefix[0] = '\0';
251 loginfo.nlgroup = li->u.ulog.group;
252 loginfo.cprange = li->u.ulog.copy_len;
253 loginfo.qthreshold = li->u.ulog.qthreshold;
254 strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix));
257 ebt_ulog_packet(net, hooknum, skb, in, out, &loginfo, prefix);
261 ebt_ulog_tg(struct sk_buff *skb, const struct xt_action_param *par)
263 struct net *net = dev_net(par->in ? par->in : par->out);
265 ebt_ulog_packet(net, par->hooknum, skb, par->in, par->out,
266 par->targinfo, NULL);
270 static int ebt_ulog_tg_check(const struct xt_tgchk_param *par)
272 struct ebt_ulog_info *uloginfo = par->targinfo;
274 if (!par->net->xt.ebt_ulog_warn_deprecated) {
275 pr_info("ebt_ulog is deprecated and it will be removed soon, "
276 "use ebt_nflog instead\n");
277 par->net->xt.ebt_ulog_warn_deprecated = true;
280 if (uloginfo->nlgroup > 31)
283 uloginfo->prefix[EBT_ULOG_PREFIX_LEN - 1] = '\0';
285 if (uloginfo->qthreshold > EBT_ULOG_MAX_QLEN)
286 uloginfo->qthreshold = EBT_ULOG_MAX_QLEN;
291 static struct xt_target ebt_ulog_tg_reg __read_mostly = {
294 .family = NFPROTO_BRIDGE,
295 .target = ebt_ulog_tg,
296 .checkentry = ebt_ulog_tg_check,
297 .targetsize = sizeof(struct ebt_ulog_info),
301 static struct nf_logger ebt_ulog_logger __read_mostly = {
303 .logfn = &ebt_log_packet,
307 static int __net_init ebt_ulog_net_init(struct net *net)
310 struct ebt_ulog_net *ebt = ebt_ulog_pernet(net);
312 struct netlink_kernel_cfg cfg = {
313 .groups = EBT_ULOG_MAXNLGROUPS,
316 /* initialize ulog_buffers */
317 for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
319 setup_timer(&ebt->ulog_buffers[i].timer, ulog_timer,
320 (unsigned long)&ebt->nlgroup[i]);
321 spin_lock_init(&ebt->ulog_buffers[i].lock);
324 ebt->ebtulognl = netlink_kernel_create(net, NETLINK_NFLOG, &cfg);
328 nf_log_set(net, NFPROTO_BRIDGE, &ebt_ulog_logger);
332 static void __net_exit ebt_ulog_net_fini(struct net *net)
335 struct ebt_ulog_net *ebt = ebt_ulog_pernet(net);
337 nf_log_unset(net, &ebt_ulog_logger);
338 for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
339 ebt_ulog_buff_t *ub = &ebt->ulog_buffers[i];
340 del_timer(&ub->timer);
347 netlink_kernel_release(ebt->ebtulognl);
350 static struct pernet_operations ebt_ulog_net_ops = {
351 .init = ebt_ulog_net_init,
352 .exit = ebt_ulog_net_fini,
353 .id = &ebt_ulog_net_id,
354 .size = sizeof(struct ebt_ulog_net),
357 static int __init ebt_ulog_init(void)
361 if (nlbufsiz >= 128*1024) {
362 pr_warn("Netlink buffer has to be <= 128kB,"
363 "please try a smaller nlbufsiz parameter.\n");
367 ret = register_pernet_subsys(&ebt_ulog_net_ops);
371 ret = xt_register_target(&ebt_ulog_tg_reg);
375 nf_log_register(NFPROTO_BRIDGE, &ebt_ulog_logger);
380 unregister_pernet_subsys(&ebt_ulog_net_ops);
385 static void __exit ebt_ulog_fini(void)
387 nf_log_unregister(&ebt_ulog_logger);
388 xt_unregister_target(&ebt_ulog_tg_reg);
389 unregister_pernet_subsys(&ebt_ulog_net_ops);
392 module_init(ebt_ulog_init);
393 module_exit(ebt_ulog_fini);
394 MODULE_LICENSE("GPL");
395 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
396 MODULE_DESCRIPTION("Ebtables: Packet logging to netlink using ULOG");