xref: /linux/net/core/rtnetlink.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Routing netlink socket interface: protocol independent part.
7  *
8  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9  *
10  *		This program is free software; you can redistribute it and/or
11  *		modify it under the terms of the GNU General Public License
12  *		as published by the Free Software Foundation; either version
13  *		2 of the License, or (at your option) any later version.
14  *
15  *	Fixes:
16  *	Vitaly E. Lavrov		RTA_OK arithmetics was wrong.
17  */
18 
19 #include <linux/config.h>
20 #include <linux/errno.h>
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/socket.h>
24 #include <linux/kernel.h>
25 #include <linux/sched.h>
26 #include <linux/timer.h>
27 #include <linux/string.h>
28 #include <linux/sockios.h>
29 #include <linux/net.h>
30 #include <linux/fcntl.h>
31 #include <linux/mm.h>
32 #include <linux/slab.h>
33 #include <linux/interrupt.h>
34 #include <linux/capability.h>
35 #include <linux/skbuff.h>
36 #include <linux/init.h>
37 #include <linux/security.h>
38 #include <linux/mutex.h>
39 
40 #include <asm/uaccess.h>
41 #include <asm/system.h>
42 #include <asm/string.h>
43 
44 #include <linux/inet.h>
45 #include <linux/netdevice.h>
46 #include <net/ip.h>
47 #include <net/protocol.h>
48 #include <net/arp.h>
49 #include <net/route.h>
50 #include <net/udp.h>
51 #include <net/sock.h>
52 #include <net/pkt_sched.h>
53 #include <net/netlink.h>
54 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
55 #include <linux/wireless.h>
56 #include <net/iw_handler.h>
57 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
58 
59 static DEFINE_MUTEX(rtnl_mutex);
60 
61 void rtnl_lock(void)
62 {
63 	mutex_lock(&rtnl_mutex);
64 }
65 
66 void __rtnl_unlock(void)
67 {
68 	mutex_unlock(&rtnl_mutex);
69 }
70 
71 void rtnl_unlock(void)
72 {
73 	mutex_unlock(&rtnl_mutex);
74 	if (rtnl && rtnl->sk_receive_queue.qlen)
75 		rtnl->sk_data_ready(rtnl, 0);
76 	netdev_run_todo();
77 }
78 
79 int rtnl_trylock(void)
80 {
81 	return mutex_trylock(&rtnl_mutex);
82 }
83 
84 int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len)
85 {
86 	memset(tb, 0, sizeof(struct rtattr*)*maxattr);
87 
88 	while (RTA_OK(rta, len)) {
89 		unsigned flavor = rta->rta_type;
90 		if (flavor && flavor <= maxattr)
91 			tb[flavor-1] = rta;
92 		rta = RTA_NEXT(rta, len);
93 	}
94 	return 0;
95 }
96 
97 struct sock *rtnl;
98 
99 struct rtnetlink_link * rtnetlink_links[NPROTO];
100 
101 static const int rtm_min[RTM_NR_FAMILIES] =
102 {
103 	[RTM_FAM(RTM_NEWLINK)]      = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
104 	[RTM_FAM(RTM_NEWADDR)]      = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
105 	[RTM_FAM(RTM_NEWROUTE)]     = NLMSG_LENGTH(sizeof(struct rtmsg)),
106 	[RTM_FAM(RTM_NEWNEIGH)]     = NLMSG_LENGTH(sizeof(struct ndmsg)),
107 	[RTM_FAM(RTM_NEWRULE)]      = NLMSG_LENGTH(sizeof(struct rtmsg)),
108 	[RTM_FAM(RTM_NEWQDISC)]     = NLMSG_LENGTH(sizeof(struct tcmsg)),
109 	[RTM_FAM(RTM_NEWTCLASS)]    = NLMSG_LENGTH(sizeof(struct tcmsg)),
110 	[RTM_FAM(RTM_NEWTFILTER)]   = NLMSG_LENGTH(sizeof(struct tcmsg)),
111 	[RTM_FAM(RTM_NEWACTION)]    = NLMSG_LENGTH(sizeof(struct tcamsg)),
112 	[RTM_FAM(RTM_NEWPREFIX)]    = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
113 	[RTM_FAM(RTM_GETMULTICAST)] = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
114 	[RTM_FAM(RTM_GETANYCAST)]   = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
115 	[RTM_FAM(RTM_NEWNEIGHTBL)]  = NLMSG_LENGTH(sizeof(struct ndtmsg)),
116 };
117 
118 static const int rta_max[RTM_NR_FAMILIES] =
119 {
120 	[RTM_FAM(RTM_NEWLINK)]      = IFLA_MAX,
121 	[RTM_FAM(RTM_NEWADDR)]      = IFA_MAX,
122 	[RTM_FAM(RTM_NEWROUTE)]     = RTA_MAX,
123 	[RTM_FAM(RTM_NEWNEIGH)]     = NDA_MAX,
124 	[RTM_FAM(RTM_NEWRULE)]      = RTA_MAX,
125 	[RTM_FAM(RTM_NEWQDISC)]     = TCA_MAX,
126 	[RTM_FAM(RTM_NEWTCLASS)]    = TCA_MAX,
127 	[RTM_FAM(RTM_NEWTFILTER)]   = TCA_MAX,
128 	[RTM_FAM(RTM_NEWACTION)]    = TCAA_MAX,
129 	[RTM_FAM(RTM_NEWNEIGHTBL)]  = NDTA_MAX,
130 };
131 
132 void __rta_fill(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
133 {
134 	struct rtattr *rta;
135 	int size = RTA_LENGTH(attrlen);
136 
137 	rta = (struct rtattr*)skb_put(skb, RTA_ALIGN(size));
138 	rta->rta_type = attrtype;
139 	rta->rta_len = size;
140 	memcpy(RTA_DATA(rta), data, attrlen);
141 	memset(RTA_DATA(rta) + attrlen, 0, RTA_ALIGN(size) - size);
142 }
143 
144 size_t rtattr_strlcpy(char *dest, const struct rtattr *rta, size_t size)
145 {
146 	size_t ret = RTA_PAYLOAD(rta);
147 	char *src = RTA_DATA(rta);
148 
149 	if (ret > 0 && src[ret - 1] == '\0')
150 		ret--;
151 	if (size > 0) {
152 		size_t len = (ret >= size) ? size - 1 : ret;
153 		memset(dest, 0, size);
154 		memcpy(dest, src, len);
155 	}
156 	return ret;
157 }
158 
159 int rtnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
160 {
161 	int err = 0;
162 
163 	NETLINK_CB(skb).dst_group = group;
164 	if (echo)
165 		atomic_inc(&skb->users);
166 	netlink_broadcast(rtnl, skb, pid, group, GFP_KERNEL);
167 	if (echo)
168 		err = netlink_unicast(rtnl, skb, pid, MSG_DONTWAIT);
169 	return err;
170 }
171 
172 int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics)
173 {
174 	struct rtattr *mx = (struct rtattr*)skb->tail;
175 	int i;
176 
177 	RTA_PUT(skb, RTA_METRICS, 0, NULL);
178 	for (i=0; i<RTAX_MAX; i++) {
179 		if (metrics[i])
180 			RTA_PUT(skb, i+1, sizeof(u32), metrics+i);
181 	}
182 	mx->rta_len = skb->tail - (u8*)mx;
183 	if (mx->rta_len == RTA_LENGTH(0))
184 		skb_trim(skb, (u8*)mx - skb->data);
185 	return 0;
186 
187 rtattr_failure:
188 	skb_trim(skb, (u8*)mx - skb->data);
189 	return -1;
190 }
191 
192 
193 static void set_operstate(struct net_device *dev, unsigned char transition)
194 {
195 	unsigned char operstate = dev->operstate;
196 
197 	switch(transition) {
198 	case IF_OPER_UP:
199 		if ((operstate == IF_OPER_DORMANT ||
200 		     operstate == IF_OPER_UNKNOWN) &&
201 		    !netif_dormant(dev))
202 			operstate = IF_OPER_UP;
203 		break;
204 
205 	case IF_OPER_DORMANT:
206 		if (operstate == IF_OPER_UP ||
207 		    operstate == IF_OPER_UNKNOWN)
208 			operstate = IF_OPER_DORMANT;
209 		break;
210 	};
211 
212 	if (dev->operstate != operstate) {
213 		write_lock_bh(&dev_base_lock);
214 		dev->operstate = operstate;
215 		write_unlock_bh(&dev_base_lock);
216 		netdev_state_change(dev);
217 	}
218 }
219 
220 static int rtnetlink_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
221 				 int type, u32 pid, u32 seq, u32 change,
222 				 unsigned int flags)
223 {
224 	struct ifinfomsg *r;
225 	struct nlmsghdr  *nlh;
226 	unsigned char	 *b = skb->tail;
227 
228 	nlh = NLMSG_NEW(skb, pid, seq, type, sizeof(*r), flags);
229 	r = NLMSG_DATA(nlh);
230 	r->ifi_family = AF_UNSPEC;
231 	r->__ifi_pad = 0;
232 	r->ifi_type = dev->type;
233 	r->ifi_index = dev->ifindex;
234 	r->ifi_flags = dev_get_flags(dev);
235 	r->ifi_change = change;
236 
237 	RTA_PUT(skb, IFLA_IFNAME, strlen(dev->name)+1, dev->name);
238 
239 	if (1) {
240 		u32 txqlen = dev->tx_queue_len;
241 		RTA_PUT(skb, IFLA_TXQLEN, sizeof(txqlen), &txqlen);
242 	}
243 
244 	if (1) {
245 		u32 weight = dev->weight;
246 		RTA_PUT(skb, IFLA_WEIGHT, sizeof(weight), &weight);
247 	}
248 
249 	if (1) {
250 		u8 operstate = netif_running(dev)?dev->operstate:IF_OPER_DOWN;
251 		u8 link_mode = dev->link_mode;
252 		RTA_PUT(skb, IFLA_OPERSTATE, sizeof(operstate), &operstate);
253 		RTA_PUT(skb, IFLA_LINKMODE, sizeof(link_mode), &link_mode);
254 	}
255 
256 	if (1) {
257 		struct rtnl_link_ifmap map = {
258 			.mem_start   = dev->mem_start,
259 			.mem_end     = dev->mem_end,
260 			.base_addr   = dev->base_addr,
261 			.irq         = dev->irq,
262 			.dma         = dev->dma,
263 			.port        = dev->if_port,
264 		};
265 		RTA_PUT(skb, IFLA_MAP, sizeof(map), &map);
266 	}
267 
268 	if (dev->addr_len) {
269 		RTA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
270 		RTA_PUT(skb, IFLA_BROADCAST, dev->addr_len, dev->broadcast);
271 	}
272 
273 	if (1) {
274 		u32 mtu = dev->mtu;
275 		RTA_PUT(skb, IFLA_MTU, sizeof(mtu), &mtu);
276 	}
277 
278 	if (dev->ifindex != dev->iflink) {
279 		u32 iflink = dev->iflink;
280 		RTA_PUT(skb, IFLA_LINK, sizeof(iflink), &iflink);
281 	}
282 
283 	if (dev->qdisc_sleeping)
284 		RTA_PUT(skb, IFLA_QDISC,
285 			strlen(dev->qdisc_sleeping->ops->id) + 1,
286 			dev->qdisc_sleeping->ops->id);
287 
288 	if (dev->master) {
289 		u32 master = dev->master->ifindex;
290 		RTA_PUT(skb, IFLA_MASTER, sizeof(master), &master);
291 	}
292 
293 	if (dev->get_stats) {
294 		unsigned long *stats = (unsigned long*)dev->get_stats(dev);
295 		if (stats) {
296 			struct rtattr  *a;
297 			__u32	       *s;
298 			int		i;
299 			int		n = sizeof(struct rtnl_link_stats)/4;
300 
301 			a = __RTA_PUT(skb, IFLA_STATS, n*4);
302 			s = RTA_DATA(a);
303 			for (i=0; i<n; i++)
304 				s[i] = stats[i];
305 		}
306 	}
307 	nlh->nlmsg_len = skb->tail - b;
308 	return skb->len;
309 
310 nlmsg_failure:
311 rtattr_failure:
312 	skb_trim(skb, b - skb->data);
313 	return -1;
314 }
315 
316 static int rtnetlink_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
317 {
318 	int idx;
319 	int s_idx = cb->args[0];
320 	struct net_device *dev;
321 
322 	read_lock(&dev_base_lock);
323 	for (dev=dev_base, idx=0; dev; dev = dev->next, idx++) {
324 		if (idx < s_idx)
325 			continue;
326 		if (rtnetlink_fill_ifinfo(skb, dev, RTM_NEWLINK,
327 					  NETLINK_CB(cb->skb).pid,
328 					  cb->nlh->nlmsg_seq, 0,
329 					  NLM_F_MULTI) <= 0)
330 			break;
331 	}
332 	read_unlock(&dev_base_lock);
333 	cb->args[0] = idx;
334 
335 	return skb->len;
336 }
337 
338 static int do_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
339 {
340 	struct ifinfomsg  *ifm = NLMSG_DATA(nlh);
341 	struct rtattr    **ida = arg;
342 	struct net_device *dev;
343 	int err, send_addr_notify = 0;
344 
345 	if (ifm->ifi_index >= 0)
346 		dev = dev_get_by_index(ifm->ifi_index);
347 	else if (ida[IFLA_IFNAME - 1]) {
348 		char ifname[IFNAMSIZ];
349 
350 		if (rtattr_strlcpy(ifname, ida[IFLA_IFNAME - 1],
351 		                   IFNAMSIZ) >= IFNAMSIZ)
352 			return -EINVAL;
353 		dev = dev_get_by_name(ifname);
354 	} else
355 		return -EINVAL;
356 
357 	if (!dev)
358 		return -ENODEV;
359 
360 	err = -EINVAL;
361 
362 	if (ifm->ifi_flags)
363 		dev_change_flags(dev, ifm->ifi_flags);
364 
365 	if (ida[IFLA_MAP - 1]) {
366 		struct rtnl_link_ifmap *u_map;
367 		struct ifmap k_map;
368 
369 		if (!dev->set_config) {
370 			err = -EOPNOTSUPP;
371 			goto out;
372 		}
373 
374 		if (!netif_device_present(dev)) {
375 			err = -ENODEV;
376 			goto out;
377 		}
378 
379 		if (ida[IFLA_MAP - 1]->rta_len != RTA_LENGTH(sizeof(*u_map)))
380 			goto out;
381 
382 		u_map = RTA_DATA(ida[IFLA_MAP - 1]);
383 
384 		k_map.mem_start = (unsigned long) u_map->mem_start;
385 		k_map.mem_end = (unsigned long) u_map->mem_end;
386 		k_map.base_addr = (unsigned short) u_map->base_addr;
387 		k_map.irq = (unsigned char) u_map->irq;
388 		k_map.dma = (unsigned char) u_map->dma;
389 		k_map.port = (unsigned char) u_map->port;
390 
391 		err = dev->set_config(dev, &k_map);
392 
393 		if (err)
394 			goto out;
395 	}
396 
397 	if (ida[IFLA_ADDRESS - 1]) {
398 		if (!dev->set_mac_address) {
399 			err = -EOPNOTSUPP;
400 			goto out;
401 		}
402 		if (!netif_device_present(dev)) {
403 			err = -ENODEV;
404 			goto out;
405 		}
406 		if (ida[IFLA_ADDRESS - 1]->rta_len != RTA_LENGTH(dev->addr_len))
407 			goto out;
408 
409 		err = dev->set_mac_address(dev, RTA_DATA(ida[IFLA_ADDRESS - 1]));
410 		if (err)
411 			goto out;
412 		send_addr_notify = 1;
413 	}
414 
415 	if (ida[IFLA_BROADCAST - 1]) {
416 		if (ida[IFLA_BROADCAST - 1]->rta_len != RTA_LENGTH(dev->addr_len))
417 			goto out;
418 		memcpy(dev->broadcast, RTA_DATA(ida[IFLA_BROADCAST - 1]),
419 		       dev->addr_len);
420 		send_addr_notify = 1;
421 	}
422 
423 	if (ida[IFLA_MTU - 1]) {
424 		if (ida[IFLA_MTU - 1]->rta_len != RTA_LENGTH(sizeof(u32)))
425 			goto out;
426 		err = dev_set_mtu(dev, *((u32 *) RTA_DATA(ida[IFLA_MTU - 1])));
427 
428 		if (err)
429 			goto out;
430 
431 	}
432 
433 	if (ida[IFLA_TXQLEN - 1]) {
434 		if (ida[IFLA_TXQLEN - 1]->rta_len != RTA_LENGTH(sizeof(u32)))
435 			goto out;
436 
437 		dev->tx_queue_len = *((u32 *) RTA_DATA(ida[IFLA_TXQLEN - 1]));
438 	}
439 
440 	if (ida[IFLA_WEIGHT - 1]) {
441 		if (ida[IFLA_WEIGHT - 1]->rta_len != RTA_LENGTH(sizeof(u32)))
442 			goto out;
443 
444 		dev->weight = *((u32 *) RTA_DATA(ida[IFLA_WEIGHT - 1]));
445 	}
446 
447 	if (ida[IFLA_OPERSTATE - 1]) {
448 		if (ida[IFLA_OPERSTATE - 1]->rta_len != RTA_LENGTH(sizeof(u8)))
449 			goto out;
450 
451 		set_operstate(dev, *((u8 *) RTA_DATA(ida[IFLA_OPERSTATE - 1])));
452 	}
453 
454 	if (ida[IFLA_LINKMODE - 1]) {
455 		if (ida[IFLA_LINKMODE - 1]->rta_len != RTA_LENGTH(sizeof(u8)))
456 			goto out;
457 
458 		write_lock_bh(&dev_base_lock);
459 		dev->link_mode = *((u8 *) RTA_DATA(ida[IFLA_LINKMODE - 1]));
460 		write_unlock_bh(&dev_base_lock);
461 	}
462 
463 	if (ifm->ifi_index >= 0 && ida[IFLA_IFNAME - 1]) {
464 		char ifname[IFNAMSIZ];
465 
466 		if (rtattr_strlcpy(ifname, ida[IFLA_IFNAME - 1],
467 		                   IFNAMSIZ) >= IFNAMSIZ)
468 			goto out;
469 		err = dev_change_name(dev, ifname);
470 		if (err)
471 			goto out;
472 	}
473 
474 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
475 	if (ida[IFLA_WIRELESS - 1]) {
476 
477 		/* Call Wireless Extensions.
478 		 * Various stuff checked in there... */
479 		err = wireless_rtnetlink_set(dev, RTA_DATA(ida[IFLA_WIRELESS - 1]), ida[IFLA_WIRELESS - 1]->rta_len);
480 		if (err)
481 			goto out;
482 	}
483 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
484 
485 	err = 0;
486 
487 out:
488 	if (send_addr_notify)
489 		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
490 
491 	dev_put(dev);
492 	return err;
493 }
494 
495 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
496 static int do_getlink(struct sk_buff *in_skb, struct nlmsghdr* in_nlh, void *arg)
497 {
498 	struct ifinfomsg  *ifm = NLMSG_DATA(in_nlh);
499 	struct rtattr    **ida = arg;
500 	struct net_device *dev;
501 	struct ifinfomsg *r;
502 	struct nlmsghdr  *nlh;
503 	int err = -ENOBUFS;
504 	struct sk_buff *skb;
505 	unsigned char	 *b;
506 	char *iw_buf = NULL;
507 	int iw_buf_len = 0;
508 
509 	if (ifm->ifi_index >= 0)
510 		dev = dev_get_by_index(ifm->ifi_index);
511 	else
512 		return -EINVAL;
513 	if (!dev)
514 		return -ENODEV;
515 
516 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
517 	if (ida[IFLA_WIRELESS - 1]) {
518 
519 		/* Call Wireless Extensions. We need to know the size before
520 		 * we can alloc. Various stuff checked in there... */
521 		err = wireless_rtnetlink_get(dev, RTA_DATA(ida[IFLA_WIRELESS - 1]), ida[IFLA_WIRELESS - 1]->rta_len, &iw_buf, &iw_buf_len);
522 		if (err)
523 			goto out;
524 	}
525 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
526 
527 	/* Create a skb big enough to include all the data.
528 	 * Some requests are way bigger than 4k... Jean II */
529 	skb = alloc_skb((NLMSG_LENGTH(sizeof(*r))) + (RTA_SPACE(iw_buf_len)),
530 			GFP_KERNEL);
531 	if (!skb)
532 		goto out;
533 	b = skb->tail;
534 
535 	/* Put in the message the usual good stuff */
536 	nlh = NLMSG_PUT(skb, NETLINK_CB(in_skb).pid, in_nlh->nlmsg_seq,
537 			RTM_NEWLINK, sizeof(*r));
538 	r = NLMSG_DATA(nlh);
539 	r->ifi_family = AF_UNSPEC;
540 	r->__ifi_pad = 0;
541 	r->ifi_type = dev->type;
542 	r->ifi_index = dev->ifindex;
543 	r->ifi_flags = dev->flags;
544 	r->ifi_change = 0;
545 
546 	/* Put the wireless payload if it exist */
547 	if(iw_buf != NULL)
548 		RTA_PUT(skb, IFLA_WIRELESS, iw_buf_len,
549 			iw_buf + IW_EV_POINT_OFF);
550 
551 	nlh->nlmsg_len = skb->tail - b;
552 
553 	/* Needed ? */
554 	NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
555 
556 	err = netlink_unicast(rtnl, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
557 	if (err > 0)
558 		err = 0;
559 out:
560 	if(iw_buf != NULL)
561 		kfree(iw_buf);
562 	dev_put(dev);
563 	return err;
564 
565 rtattr_failure:
566 nlmsg_failure:
567 	kfree_skb(skb);
568 	goto out;
569 }
570 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
571 
572 static int rtnetlink_dump_all(struct sk_buff *skb, struct netlink_callback *cb)
573 {
574 	int idx;
575 	int s_idx = cb->family;
576 
577 	if (s_idx == 0)
578 		s_idx = 1;
579 	for (idx=1; idx<NPROTO; idx++) {
580 		int type = cb->nlh->nlmsg_type-RTM_BASE;
581 		if (idx < s_idx || idx == PF_PACKET)
582 			continue;
583 		if (rtnetlink_links[idx] == NULL ||
584 		    rtnetlink_links[idx][type].dumpit == NULL)
585 			continue;
586 		if (idx > s_idx)
587 			memset(&cb->args[0], 0, sizeof(cb->args));
588 		if (rtnetlink_links[idx][type].dumpit(skb, cb))
589 			break;
590 	}
591 	cb->family = idx;
592 
593 	return skb->len;
594 }
595 
596 void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)
597 {
598 	struct sk_buff *skb;
599 	int size = NLMSG_SPACE(sizeof(struct ifinfomsg) +
600 			       sizeof(struct rtnl_link_ifmap) +
601 			       sizeof(struct rtnl_link_stats) + 128);
602 
603 	skb = alloc_skb(size, GFP_KERNEL);
604 	if (!skb)
605 		return;
606 
607 	if (rtnetlink_fill_ifinfo(skb, dev, type, 0, 0, change, 0) < 0) {
608 		kfree_skb(skb);
609 		return;
610 	}
611 	NETLINK_CB(skb).dst_group = RTNLGRP_LINK;
612 	netlink_broadcast(rtnl, skb, 0, RTNLGRP_LINK, GFP_KERNEL);
613 }
614 
615 /* Protected by RTNL sempahore.  */
616 static struct rtattr **rta_buf;
617 static int rtattr_max;
618 
619 /* Process one rtnetlink message. */
620 
621 static __inline__ int
622 rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
623 {
624 	struct rtnetlink_link *link;
625 	struct rtnetlink_link *link_tab;
626 	int sz_idx, kind;
627 	int min_len;
628 	int family;
629 	int type;
630 	int err;
631 
632 	/* Only requests are handled by kernel now */
633 	if (!(nlh->nlmsg_flags&NLM_F_REQUEST))
634 		return 0;
635 
636 	type = nlh->nlmsg_type;
637 
638 	/* A control message: ignore them */
639 	if (type < RTM_BASE)
640 		return 0;
641 
642 	/* Unknown message: reply with EINVAL */
643 	if (type > RTM_MAX)
644 		goto err_inval;
645 
646 	type -= RTM_BASE;
647 
648 	/* All the messages must have at least 1 byte length */
649 	if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct rtgenmsg)))
650 		return 0;
651 
652 	family = ((struct rtgenmsg*)NLMSG_DATA(nlh))->rtgen_family;
653 	if (family >= NPROTO) {
654 		*errp = -EAFNOSUPPORT;
655 		return -1;
656 	}
657 
658 	link_tab = rtnetlink_links[family];
659 	if (link_tab == NULL)
660 		link_tab = rtnetlink_links[PF_UNSPEC];
661 	link = &link_tab[type];
662 
663 	sz_idx = type>>2;
664 	kind = type&3;
665 
666 	if (kind != 2 && security_netlink_recv(skb)) {
667 		*errp = -EPERM;
668 		return -1;
669 	}
670 
671 	if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
672 		if (link->dumpit == NULL)
673 			link = &(rtnetlink_links[PF_UNSPEC][type]);
674 
675 		if (link->dumpit == NULL)
676 			goto err_inval;
677 
678 		if ((*errp = netlink_dump_start(rtnl, skb, nlh,
679 						link->dumpit, NULL)) != 0) {
680 			return -1;
681 		}
682 
683 		netlink_queue_skip(nlh, skb);
684 		return -1;
685 	}
686 
687 	memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *)));
688 
689 	min_len = rtm_min[sz_idx];
690 	if (nlh->nlmsg_len < min_len)
691 		goto err_inval;
692 
693 	if (nlh->nlmsg_len > min_len) {
694 		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
695 		struct rtattr *attr = (void*)nlh + NLMSG_ALIGN(min_len);
696 
697 		while (RTA_OK(attr, attrlen)) {
698 			unsigned flavor = attr->rta_type;
699 			if (flavor) {
700 				if (flavor > rta_max[sz_idx])
701 					goto err_inval;
702 				rta_buf[flavor-1] = attr;
703 			}
704 			attr = RTA_NEXT(attr, attrlen);
705 		}
706 	}
707 
708 	if (link->doit == NULL)
709 		link = &(rtnetlink_links[PF_UNSPEC][type]);
710 	if (link->doit == NULL)
711 		goto err_inval;
712 	err = link->doit(skb, nlh, (void *)&rta_buf[0]);
713 
714 	*errp = err;
715 	return err;
716 
717 err_inval:
718 	*errp = -EINVAL;
719 	return -1;
720 }
721 
722 static void rtnetlink_rcv(struct sock *sk, int len)
723 {
724 	unsigned int qlen = 0;
725 
726 	do {
727 		mutex_lock(&rtnl_mutex);
728 		netlink_run_queue(sk, &qlen, &rtnetlink_rcv_msg);
729 		mutex_unlock(&rtnl_mutex);
730 
731 		netdev_run_todo();
732 	} while (qlen);
733 }
734 
735 static struct rtnetlink_link link_rtnetlink_table[RTM_NR_MSGTYPES] =
736 {
737 	[RTM_GETLINK     - RTM_BASE] = {
738 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
739 					 .doit   = do_getlink,
740 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
741 					 .dumpit = rtnetlink_dump_ifinfo },
742 	[RTM_SETLINK     - RTM_BASE] = { .doit   = do_setlink		 },
743 	[RTM_GETADDR     - RTM_BASE] = { .dumpit = rtnetlink_dump_all	 },
744 	[RTM_GETROUTE    - RTM_BASE] = { .dumpit = rtnetlink_dump_all	 },
745 	[RTM_NEWNEIGH    - RTM_BASE] = { .doit   = neigh_add		 },
746 	[RTM_DELNEIGH    - RTM_BASE] = { .doit   = neigh_delete		 },
747 	[RTM_GETNEIGH    - RTM_BASE] = { .dumpit = neigh_dump_info	 },
748 	[RTM_GETRULE     - RTM_BASE] = { .dumpit = rtnetlink_dump_all	 },
749 	[RTM_GETNEIGHTBL - RTM_BASE] = { .dumpit = neightbl_dump_info	 },
750 	[RTM_SETNEIGHTBL - RTM_BASE] = { .doit   = neightbl_set		 },
751 };
752 
753 static int rtnetlink_event(struct notifier_block *this, unsigned long event, void *ptr)
754 {
755 	struct net_device *dev = ptr;
756 	switch (event) {
757 	case NETDEV_UNREGISTER:
758 		rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
759 		break;
760 	case NETDEV_REGISTER:
761 		rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U);
762 		break;
763 	case NETDEV_UP:
764 	case NETDEV_DOWN:
765 		rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);
766 		break;
767 	case NETDEV_CHANGE:
768 	case NETDEV_GOING_DOWN:
769 		break;
770 	default:
771 		rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
772 		break;
773 	}
774 	return NOTIFY_DONE;
775 }
776 
777 static struct notifier_block rtnetlink_dev_notifier = {
778 	.notifier_call	= rtnetlink_event,
779 };
780 
781 void __init rtnetlink_init(void)
782 {
783 	int i;
784 
785 	rtattr_max = 0;
786 	for (i = 0; i < ARRAY_SIZE(rta_max); i++)
787 		if (rta_max[i] > rtattr_max)
788 			rtattr_max = rta_max[i];
789 	rta_buf = kmalloc(rtattr_max * sizeof(struct rtattr *), GFP_KERNEL);
790 	if (!rta_buf)
791 		panic("rtnetlink_init: cannot allocate rta_buf\n");
792 
793 	rtnl = netlink_kernel_create(NETLINK_ROUTE, RTNLGRP_MAX, rtnetlink_rcv,
794 	                             THIS_MODULE);
795 	if (rtnl == NULL)
796 		panic("rtnetlink_init: cannot initialize rtnetlink\n");
797 	netlink_set_nonroot(NETLINK_ROUTE, NL_NONROOT_RECV);
798 	register_netdevice_notifier(&rtnetlink_dev_notifier);
799 	rtnetlink_links[PF_UNSPEC] = link_rtnetlink_table;
800 	rtnetlink_links[PF_PACKET] = link_rtnetlink_table;
801 }
802 
803 EXPORT_SYMBOL(__rta_fill);
804 EXPORT_SYMBOL(rtattr_strlcpy);
805 EXPORT_SYMBOL(rtattr_parse);
806 EXPORT_SYMBOL(rtnetlink_links);
807 EXPORT_SYMBOL(rtnetlink_put_metrics);
808 EXPORT_SYMBOL(rtnl);
809 EXPORT_SYMBOL(rtnl_lock);
810 EXPORT_SYMBOL(rtnl_trylock);
811 EXPORT_SYMBOL(rtnl_unlock);
812