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added 2.6.29.6 aldebaran kernel
[nao-ulib.git] / kernel / 2.6.29.6-aldebaran-rt / net / bridge / netfilter / ebt_ulog.c
blob2c6d6823e703dd62d226a30b740c50fab79615c7
1 /*
2 * netfilter module for userspace bridged Ethernet frames logging daemons
3 *
4 * Authors:
5 * Bart De Schuymer <bdschuym@pandora.be>
6 * Harald Welte <laforge@netfilter.org>
7 *
8 * November, 2004
9 *
10 * Based on ipt_ULOG.c, which is
11 * (C) 2000-2002 by Harald Welte <laforge@netfilter.org>
12 *
13 * This module accepts two parameters:
14 *
15 * nlbufsiz:
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
23 * by that factor.
24 *
25 * flushtimeout:
26 * Specify, after how many hundredths of a second the queue should be
27 * flushed even if it is not full yet.
28 *
29 */
30
31 #include <linux/module.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/netfilter/x_tables.h>
40 #include <linux/netfilter_bridge/ebtables.h>
41 #include <linux/netfilter_bridge/ebt_ulog.h>
42 #include <net/netfilter/nf_log.h>
43 #include <net/sock.h>
44 #include "../br_private.h"
45
46 #define PRINTR(format, args...) do { if (net_ratelimit()) \
47 printk(format , ## args); } while (0)
48
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)");
53
54 static unsigned int flushtimeout = 10;
55 module_param(flushtimeout, uint, 0600);
56 MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths ofa second) "
57 "(defaults to 10)");
58
59 typedef struct {
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 */
65 } ebt_ulog_buff_t;
66
67 static ebt_ulog_buff_t ulog_buffers[EBT_ULOG_MAXNLGROUPS];
68 static struct sock *ebtulognl;
69
70 /* send one ulog_buff_t to userspace */
71 static void ulog_send(unsigned int nlgroup)
72 {
73 ebt_ulog_buff_t *ub = &ulog_buffers[nlgroup];
74
75 if (timer_pending(&ub->timer))
76 del_timer(&ub->timer);
77
78 if (!ub->skb)
79 return;
80
81 /* last nlmsg needs NLMSG_DONE */
82 if (ub->qlen > 1)
83 ub->lastnlh->nlmsg_type = NLMSG_DONE;
84
85 NETLINK_CB(ub->skb).dst_group = nlgroup + 1;
86 netlink_broadcast(ebtulognl, ub->skb, 0, nlgroup + 1, GFP_ATOMIC);
87
88 ub->qlen = 0;
89 ub->skb = NULL;
90 }
91
92 /* timer function to flush queue in flushtimeout time */
93 static void ulog_timer(unsigned long data)
94 {
95 spin_lock_bh(&ulog_buffers[data].lock);
96 if (ulog_buffers[data].skb)
97 ulog_send(data);
98 spin_unlock_bh(&ulog_buffers[data].lock);
99 }
100
101 static struct sk_buff *ulog_alloc_skb(unsigned int size)
102 {
103 struct sk_buff *skb;
104 unsigned int n;
105
106 n = max(size, nlbufsiz);
107 skb = alloc_skb(n, GFP_ATOMIC);
108 if (!skb) {
109 PRINTR(KERN_ERR "ebt_ulog: can't alloc whole buffer "
110 "of size %ub!\n", n);
111 if (n > size) {
112 /* try to allocate only as much as we need for
113 * current packet */
114 skb = alloc_skb(size, GFP_ATOMIC);
115 if (!skb)
116 PRINTR(KERN_ERR "ebt_ulog: can't even allocate "
117 "buffer of size %ub\n", size);
118 }
119 }
120
121 return skb;
122 }
123
124 static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb,
125 const struct net_device *in, const struct net_device *out,
126 const struct ebt_ulog_info *uloginfo, const char *prefix)
127 {
128 ebt_ulog_packet_msg_t *pm;
129 size_t size, copy_len;
130 struct nlmsghdr *nlh;
131 unsigned int group = uloginfo->nlgroup;
132 ebt_ulog_buff_t *ub = &ulog_buffers[group];
133 spinlock_t *lock = &ub->lock;
134 ktime_t kt;
135
136 if ((uloginfo->cprange == 0) ||
137 (uloginfo->cprange > skb->len + ETH_HLEN))
138 copy_len = skb->len + ETH_HLEN;
139 else
140 copy_len = uloginfo->cprange;
141
142 size = NLMSG_SPACE(sizeof(*pm) + copy_len);
143 if (size > nlbufsiz) {
144 PRINTR("ebt_ulog: Size %Zd needed, but nlbufsiz=%d\n",
145 size, nlbufsiz);
146 return;
147 }
148
149 spin_lock_bh(lock);
150
151 if (!ub->skb) {
152 if (!(ub->skb = ulog_alloc_skb(size)))
153 goto alloc_failure;
154 } else if (size > skb_tailroom(ub->skb)) {
155 ulog_send(group);
156
157 if (!(ub->skb = ulog_alloc_skb(size)))
158 goto alloc_failure;
159 }
160
161 nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, 0,
162 size - NLMSG_ALIGN(sizeof(*nlh)));
163 ub->qlen++;
164
165 pm = NLMSG_DATA(nlh);
166
167 /* Fill in the ulog data */
168 pm->version = EBT_ULOG_VERSION;
169 kt = ktime_get_real();
170 pm->stamp = ktime_to_timeval(kt);
171 if (ub->qlen == 1)
172 ub->skb->tstamp = kt;
173 pm->data_len = copy_len;
174 pm->mark = skb->mark;
175 pm->hook = hooknr;
176 if (uloginfo->prefix != NULL)
177 strcpy(pm->prefix, uloginfo->prefix);
178 else
179 *(pm->prefix) = '\0';
180
181 if (in) {
182 strcpy(pm->physindev, in->name);
183 /* If in isn't a bridge, then physindev==indev */
184 if (in->br_port)
185 strcpy(pm->indev, in->br_port->br->dev->name);
186 else
187 strcpy(pm->indev, in->name);
188 } else
189 pm->indev[0] = pm->physindev[0] = '\0';
190
191 if (out) {
192 /* If out exists, then out is a bridge port */
193 strcpy(pm->physoutdev, out->name);
194 strcpy(pm->outdev, out->br_port->br->dev->name);
195 } else
196 pm->outdev[0] = pm->physoutdev[0] = '\0';
197
198 if (skb_copy_bits(skb, -ETH_HLEN, pm->data, copy_len) < 0)
199 BUG();
200
201 if (ub->qlen > 1)
202 ub->lastnlh->nlmsg_flags |= NLM_F_MULTI;
203
204 ub->lastnlh = nlh;
205
206 if (ub->qlen >= uloginfo->qthreshold)
207 ulog_send(group);
208 else if (!timer_pending(&ub->timer)) {
209 ub->timer.expires = jiffies + flushtimeout * HZ / 100;
210 add_timer(&ub->timer);
211 }
212
213 unlock:
214 spin_unlock_bh(lock);
215
216 return;
217
218 nlmsg_failure:
219 printk(KERN_CRIT "ebt_ulog: error during NLMSG_PUT. This should "
220 "not happen, please report to author.\n");
221 goto unlock;
222 alloc_failure:
223 goto unlock;
224 }
225
226 /* this function is registered with the netfilter core */
227 static void ebt_log_packet(u_int8_t pf, unsigned int hooknum,
228 const struct sk_buff *skb, const struct net_device *in,
229 const struct net_device *out, const struct nf_loginfo *li,
230 const char *prefix)
231 {
232 struct ebt_ulog_info loginfo;
233
234 if (!li || li->type != NF_LOG_TYPE_ULOG) {
235 loginfo.nlgroup = EBT_ULOG_DEFAULT_NLGROUP;
236 loginfo.cprange = 0;
237 loginfo.qthreshold = EBT_ULOG_DEFAULT_QTHRESHOLD;
238 loginfo.prefix[0] = '\0';
239 } else {
240 loginfo.nlgroup = li->u.ulog.group;
241 loginfo.cprange = li->u.ulog.copy_len;
242 loginfo.qthreshold = li->u.ulog.qthreshold;
243 strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix));
244 }
245
246 ebt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix);
247 }
248
249 static unsigned int
250 ebt_ulog_tg(struct sk_buff *skb, const struct xt_target_param *par)
251 {
252 ebt_ulog_packet(par->hooknum, skb, par->in, par->out,
253 par->targinfo, NULL);
254 return EBT_CONTINUE;
255 }
256
257 static bool ebt_ulog_tg_check(const struct xt_tgchk_param *par)
258 {
259 struct ebt_ulog_info *uloginfo = par->targinfo;
260
261 if (uloginfo->nlgroup > 31)
262 return false;
263
264 uloginfo->prefix[EBT_ULOG_PREFIX_LEN - 1] = '\0';
265
266 if (uloginfo->qthreshold > EBT_ULOG_MAX_QLEN)
267 uloginfo->qthreshold = EBT_ULOG_MAX_QLEN;
268
269 return 0;
270 }
271
272 static struct xt_target ebt_ulog_tg_reg __read_mostly = {
273 .name = "ulog",
274 .revision = 0,
275 .family = NFPROTO_BRIDGE,
276 .target = ebt_ulog_tg,
277 .checkentry = ebt_ulog_tg_check,
278 .targetsize = XT_ALIGN(sizeof(struct ebt_ulog_info)),
279 .me = THIS_MODULE,
280 };
281
282 static const struct nf_logger ebt_ulog_logger = {
283 .name = "ulog",
284 .logfn = &ebt_log_packet,
285 .me = THIS_MODULE,
286 };
287
288 static int __init ebt_ulog_init(void)
289 {
290 bool ret = true;
291 int i;
292
293 if (nlbufsiz >= 128*1024) {
294 printk(KERN_NOTICE "ebt_ulog: Netlink buffer has to be <= 128kB,"
295 " please try a smaller nlbufsiz parameter.\n");
296 return false;
297 }
298
299 /* initialize ulog_buffers */
300 for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
301 setup_timer(&ulog_buffers[i].timer, ulog_timer, i);
302 spin_lock_init(&ulog_buffers[i].lock);
303 }
304
305 ebtulognl = netlink_kernel_create(&init_net, NETLINK_NFLOG,
306 EBT_ULOG_MAXNLGROUPS, NULL, NULL,
307 THIS_MODULE);
308 if (!ebtulognl) {
309 printk(KERN_WARNING KBUILD_MODNAME ": out of memory trying to "
310 "call netlink_kernel_create\n");
311 ret = false;
312 } else if (xt_register_target(&ebt_ulog_tg_reg) != 0) {
313 netlink_kernel_release(ebtulognl);
314 }
315
316 if (ret)
317 nf_log_register(NFPROTO_BRIDGE, &ebt_ulog_logger);
318
319 return ret;
320 }
321
322 static void __exit ebt_ulog_fini(void)
323 {
324 ebt_ulog_buff_t *ub;
325 int i;
326
327 nf_log_unregister(&ebt_ulog_logger);
328 xt_unregister_target(&ebt_ulog_tg_reg);
329 for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
330 ub = &ulog_buffers[i];
331 if (timer_pending(&ub->timer))
332 del_timer(&ub->timer);
333 spin_lock_bh(&ub->lock);
334 if (ub->skb) {
335 kfree_skb(ub->skb);
336 ub->skb = NULL;
337 }
338 spin_unlock_bh(&ub->lock);
339 }
340 netlink_kernel_release(ebtulognl);
341 }
342
343 module_init(ebt_ulog_init);
344 module_exit(ebt_ulog_fini);
345 MODULE_LICENSE("GPL");
346 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
347 MODULE_DESCRIPTION("Ebtables: Packet logging to netlink using ULOG");
Nao low-level kernelspace/userspace library that runs on our robots, Nao-Team HTWK