xref: /linux/net/core/rtnetlink.c (revision f24e9f586b377749dff37554696cf3a105540c94)
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/errno.h>
20 #include <linux/module.h>
21 #include <linux/types.h>
22 #include <linux/socket.h>
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/timer.h>
26 #include <linux/string.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/fcntl.h>
30 #include <linux/mm.h>
31 #include <linux/slab.h>
32 #include <linux/interrupt.h>
33 #include <linux/capability.h>
34 #include <linux/skbuff.h>
35 #include <linux/init.h>
36 #include <linux/security.h>
37 #include <linux/mutex.h>
38 
39 #include <asm/uaccess.h>
40 #include <asm/system.h>
41 #include <asm/string.h>
42 
43 #include <linux/inet.h>
44 #include <linux/netdevice.h>
45 #include <net/ip.h>
46 #include <net/protocol.h>
47 #include <net/arp.h>
48 #include <net/route.h>
49 #include <net/udp.h>
50 #include <net/sock.h>
51 #include <net/pkt_sched.h>
52 #include <net/netlink.h>
53 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
54 #include <linux/wireless.h>
55 #include <net/iw_handler.h>
56 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
57 
58 static DEFINE_MUTEX(rtnl_mutex);
59 
60 void rtnl_lock(void)
61 {
62 	mutex_lock(&rtnl_mutex);
63 }
64 
65 void __rtnl_unlock(void)
66 {
67 	mutex_unlock(&rtnl_mutex);
68 }
69 
70 void rtnl_unlock(void)
71 {
72 	mutex_unlock(&rtnl_mutex);
73 	if (rtnl && rtnl->sk_receive_queue.qlen)
74 		rtnl->sk_data_ready(rtnl, 0);
75 	netdev_run_todo();
76 }
77 
78 int rtnl_trylock(void)
79 {
80 	return mutex_trylock(&rtnl_mutex);
81 }
82 
83 int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len)
84 {
85 	memset(tb, 0, sizeof(struct rtattr*)*maxattr);
86 
87 	while (RTA_OK(rta, len)) {
88 		unsigned flavor = rta->rta_type;
89 		if (flavor && flavor <= maxattr)
90 			tb[flavor-1] = rta;
91 		rta = RTA_NEXT(rta, len);
92 	}
93 	return 0;
94 }
95 
96 struct sock *rtnl;
97 
98 struct rtnetlink_link * rtnetlink_links[NPROTO];
99 
100 static const int rtm_min[RTM_NR_FAMILIES] =
101 {
102 	[RTM_FAM(RTM_NEWLINK)]      = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
103 	[RTM_FAM(RTM_NEWADDR)]      = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
104 	[RTM_FAM(RTM_NEWROUTE)]     = NLMSG_LENGTH(sizeof(struct rtmsg)),
105 	[RTM_FAM(RTM_NEWNEIGH)]     = NLMSG_LENGTH(sizeof(struct ndmsg)),
106 	[RTM_FAM(RTM_NEWRULE)]      = NLMSG_LENGTH(sizeof(struct rtmsg)),
107 	[RTM_FAM(RTM_NEWQDISC)]     = NLMSG_LENGTH(sizeof(struct tcmsg)),
108 	[RTM_FAM(RTM_NEWTCLASS)]    = NLMSG_LENGTH(sizeof(struct tcmsg)),
109 	[RTM_FAM(RTM_NEWTFILTER)]   = NLMSG_LENGTH(sizeof(struct tcmsg)),
110 	[RTM_FAM(RTM_NEWACTION)]    = NLMSG_LENGTH(sizeof(struct tcamsg)),
111 	[RTM_FAM(RTM_NEWPREFIX)]    = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
112 	[RTM_FAM(RTM_GETMULTICAST)] = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
113 	[RTM_FAM(RTM_GETANYCAST)]   = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
114 	[RTM_FAM(RTM_NEWNEIGHTBL)]  = NLMSG_LENGTH(sizeof(struct ndtmsg)),
115 };
116 
117 static const int rta_max[RTM_NR_FAMILIES] =
118 {
119 	[RTM_FAM(RTM_NEWLINK)]      = IFLA_MAX,
120 	[RTM_FAM(RTM_NEWADDR)]      = IFA_MAX,
121 	[RTM_FAM(RTM_NEWROUTE)]     = RTA_MAX,
122 	[RTM_FAM(RTM_NEWNEIGH)]     = NDA_MAX,
123 	[RTM_FAM(RTM_NEWRULE)]      = RTA_MAX,
124 	[RTM_FAM(RTM_NEWQDISC)]     = TCA_MAX,
125 	[RTM_FAM(RTM_NEWTCLASS)]    = TCA_MAX,
126 	[RTM_FAM(RTM_NEWTFILTER)]   = TCA_MAX,
127 	[RTM_FAM(RTM_NEWACTION)]    = TCAA_MAX,
128 	[RTM_FAM(RTM_NEWNEIGHTBL)]  = NDTA_MAX,
129 };
130 
131 void __rta_fill(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
132 {
133 	struct rtattr *rta;
134 	int size = RTA_LENGTH(attrlen);
135 
136 	rta = (struct rtattr*)skb_put(skb, RTA_ALIGN(size));
137 	rta->rta_type = attrtype;
138 	rta->rta_len = size;
139 	memcpy(RTA_DATA(rta), data, attrlen);
140 	memset(RTA_DATA(rta) + attrlen, 0, RTA_ALIGN(size) - size);
141 }
142 
143 size_t rtattr_strlcpy(char *dest, const struct rtattr *rta, size_t size)
144 {
145 	size_t ret = RTA_PAYLOAD(rta);
146 	char *src = RTA_DATA(rta);
147 
148 	if (ret > 0 && src[ret - 1] == '\0')
149 		ret--;
150 	if (size > 0) {
151 		size_t len = (ret >= size) ? size - 1 : ret;
152 		memset(dest, 0, size);
153 		memcpy(dest, src, len);
154 	}
155 	return ret;
156 }
157 
158 int rtnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo)
159 {
160 	int err = 0;
161 
162 	NETLINK_CB(skb).dst_group = group;
163 	if (echo)
164 		atomic_inc(&skb->users);
165 	netlink_broadcast(rtnl, skb, pid, group, GFP_KERNEL);
166 	if (echo)
167 		err = netlink_unicast(rtnl, skb, pid, MSG_DONTWAIT);
168 	return err;
169 }
170 
171 int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics)
172 {
173 	struct rtattr *mx = (struct rtattr*)skb->tail;
174 	int i;
175 
176 	RTA_PUT(skb, RTA_METRICS, 0, NULL);
177 	for (i=0; i<RTAX_MAX; i++) {
178 		if (metrics[i])
179 			RTA_PUT(skb, i+1, sizeof(u32), metrics+i);
180 	}
181 	mx->rta_len = skb->tail - (u8*)mx;
182 	if (mx->rta_len == RTA_LENGTH(0))
183 		skb_trim(skb, (u8*)mx - skb->data);
184 	return 0;
185 
186 rtattr_failure:
187 	skb_trim(skb, (u8*)mx - skb->data);
188 	return -1;
189 }
190 
191 
192 static void set_operstate(struct net_device *dev, unsigned char transition)
193 {
194 	unsigned char operstate = dev->operstate;
195 
196 	switch(transition) {
197 	case IF_OPER_UP:
198 		if ((operstate == IF_OPER_DORMANT ||
199 		     operstate == IF_OPER_UNKNOWN) &&
200 		    !netif_dormant(dev))
201 			operstate = IF_OPER_UP;
202 		break;
203 
204 	case IF_OPER_DORMANT:
205 		if (operstate == IF_OPER_UP ||
206 		    operstate == IF_OPER_UNKNOWN)
207 			operstate = IF_OPER_DORMANT;
208 		break;
209 	};
210 
211 	if (dev->operstate != operstate) {
212 		write_lock_bh(&dev_base_lock);
213 		dev->operstate = operstate;
214 		write_unlock_bh(&dev_base_lock);
215 		netdev_state_change(dev);
216 	}
217 }
218 
219 static int rtnetlink_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
220 				 int type, u32 pid, u32 seq, u32 change,
221 				 unsigned int flags)
222 {
223 	struct ifinfomsg *r;
224 	struct nlmsghdr  *nlh;
225 	unsigned char	 *b = skb->tail;
226 
227 	nlh = NLMSG_NEW(skb, pid, seq, type, sizeof(*r), flags);
228 	r = NLMSG_DATA(nlh);
229 	r->ifi_family = AF_UNSPEC;
230 	r->__ifi_pad = 0;
231 	r->ifi_type = dev->type;
232 	r->ifi_index = dev->ifindex;
233 	r->ifi_flags = dev_get_flags(dev);
234 	r->ifi_change = change;
235 
236 	RTA_PUT(skb, IFLA_IFNAME, strlen(dev->name)+1, dev->name);
237 
238 	if (1) {
239 		u32 txqlen = dev->tx_queue_len;
240 		RTA_PUT(skb, IFLA_TXQLEN, sizeof(txqlen), &txqlen);
241 	}
242 
243 	if (1) {
244 		u32 weight = dev->weight;
245 		RTA_PUT(skb, IFLA_WEIGHT, sizeof(weight), &weight);
246 	}
247 
248 	if (1) {
249 		u8 operstate = netif_running(dev)?dev->operstate:IF_OPER_DOWN;
250 		u8 link_mode = dev->link_mode;
251 		RTA_PUT(skb, IFLA_OPERSTATE, sizeof(operstate), &operstate);
252 		RTA_PUT(skb, IFLA_LINKMODE, sizeof(link_mode), &link_mode);
253 	}
254 
255 	if (1) {
256 		struct rtnl_link_ifmap map = {
257 			.mem_start   = dev->mem_start,
258 			.mem_end     = dev->mem_end,
259 			.base_addr   = dev->base_addr,
260 			.irq         = dev->irq,
261 			.dma         = dev->dma,
262 			.port        = dev->if_port,
263 		};
264 		RTA_PUT(skb, IFLA_MAP, sizeof(map), &map);
265 	}
266 
267 	if (dev->addr_len) {
268 		RTA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
269 		RTA_PUT(skb, IFLA_BROADCAST, dev->addr_len, dev->broadcast);
270 	}
271 
272 	if (1) {
273 		u32 mtu = dev->mtu;
274 		RTA_PUT(skb, IFLA_MTU, sizeof(mtu), &mtu);
275 	}
276 
277 	if (dev->ifindex != dev->iflink) {
278 		u32 iflink = dev->iflink;
279 		RTA_PUT(skb, IFLA_LINK, sizeof(iflink), &iflink);
280 	}
281 
282 	if (dev->qdisc_sleeping)
283 		RTA_PUT(skb, IFLA_QDISC,
284 			strlen(dev->qdisc_sleeping->ops->id) + 1,
285 			dev->qdisc_sleeping->ops->id);
286 
287 	if (dev->master) {
288 		u32 master = dev->master->ifindex;
289 		RTA_PUT(skb, IFLA_MASTER, sizeof(master), &master);
290 	}
291 
292 	if (dev->get_stats) {
293 		unsigned long *stats = (unsigned long*)dev->get_stats(dev);
294 		if (stats) {
295 			struct rtattr  *a;
296 			__u32	       *s;
297 			int		i;
298 			int		n = sizeof(struct rtnl_link_stats)/4;
299 
300 			a = __RTA_PUT(skb, IFLA_STATS, n*4);
301 			s = RTA_DATA(a);
302 			for (i=0; i<n; i++)
303 				s[i] = stats[i];
304 		}
305 	}
306 	nlh->nlmsg_len = skb->tail - b;
307 	return skb->len;
308 
309 nlmsg_failure:
310 rtattr_failure:
311 	skb_trim(skb, b - skb->data);
312 	return -1;
313 }
314 
315 static int rtnetlink_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
316 {
317 	int idx;
318 	int s_idx = cb->args[0];
319 	struct net_device *dev;
320 
321 	read_lock(&dev_base_lock);
322 	for (dev=dev_base, idx=0; dev; dev = dev->next, idx++) {
323 		if (idx < s_idx)
324 			continue;
325 		if (rtnetlink_fill_ifinfo(skb, dev, RTM_NEWLINK,
326 					  NETLINK_CB(cb->skb).pid,
327 					  cb->nlh->nlmsg_seq, 0,
328 					  NLM_F_MULTI) <= 0)
329 			break;
330 	}
331 	read_unlock(&dev_base_lock);
332 	cb->args[0] = idx;
333 
334 	return skb->len;
335 }
336 
337 static int do_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
338 {
339 	struct ifinfomsg  *ifm = NLMSG_DATA(nlh);
340 	struct rtattr    **ida = arg;
341 	struct net_device *dev;
342 	int err, send_addr_notify = 0;
343 
344 	if (ifm->ifi_index >= 0)
345 		dev = dev_get_by_index(ifm->ifi_index);
346 	else if (ida[IFLA_IFNAME - 1]) {
347 		char ifname[IFNAMSIZ];
348 
349 		if (rtattr_strlcpy(ifname, ida[IFLA_IFNAME - 1],
350 		                   IFNAMSIZ) >= IFNAMSIZ)
351 			return -EINVAL;
352 		dev = dev_get_by_name(ifname);
353 	} else
354 		return -EINVAL;
355 
356 	if (!dev)
357 		return -ENODEV;
358 
359 	err = -EINVAL;
360 
361 	if (ifm->ifi_flags)
362 		dev_change_flags(dev, ifm->ifi_flags);
363 
364 	if (ida[IFLA_MAP - 1]) {
365 		struct rtnl_link_ifmap *u_map;
366 		struct ifmap k_map;
367 
368 		if (!dev->set_config) {
369 			err = -EOPNOTSUPP;
370 			goto out;
371 		}
372 
373 		if (!netif_device_present(dev)) {
374 			err = -ENODEV;
375 			goto out;
376 		}
377 
378 		if (ida[IFLA_MAP - 1]->rta_len != RTA_LENGTH(sizeof(*u_map)))
379 			goto out;
380 
381 		u_map = RTA_DATA(ida[IFLA_MAP - 1]);
382 
383 		k_map.mem_start = (unsigned long) u_map->mem_start;
384 		k_map.mem_end = (unsigned long) u_map->mem_end;
385 		k_map.base_addr = (unsigned short) u_map->base_addr;
386 		k_map.irq = (unsigned char) u_map->irq;
387 		k_map.dma = (unsigned char) u_map->dma;
388 		k_map.port = (unsigned char) u_map->port;
389 
390 		err = dev->set_config(dev, &k_map);
391 
392 		if (err)
393 			goto out;
394 	}
395 
396 	if (ida[IFLA_ADDRESS - 1]) {
397 		struct sockaddr *sa;
398 		int len;
399 
400 		if (!dev->set_mac_address) {
401 			err = -EOPNOTSUPP;
402 			goto out;
403 		}
404 		if (!netif_device_present(dev)) {
405 			err = -ENODEV;
406 			goto out;
407 		}
408 		if (ida[IFLA_ADDRESS - 1]->rta_len != RTA_LENGTH(dev->addr_len))
409 			goto out;
410 
411 		len = sizeof(sa_family_t) + dev->addr_len;
412 		sa = kmalloc(len, GFP_KERNEL);
413 		if (!sa) {
414 			err = -ENOMEM;
415 			goto out;
416 		}
417 		sa->sa_family = dev->type;
418 		memcpy(sa->sa_data, RTA_DATA(ida[IFLA_ADDRESS - 1]),
419 		       dev->addr_len);
420 		err = dev->set_mac_address(dev, sa);
421 		kfree(sa);
422 		if (err)
423 			goto out;
424 		send_addr_notify = 1;
425 	}
426 
427 	if (ida[IFLA_BROADCAST - 1]) {
428 		if (ida[IFLA_BROADCAST - 1]->rta_len != RTA_LENGTH(dev->addr_len))
429 			goto out;
430 		memcpy(dev->broadcast, RTA_DATA(ida[IFLA_BROADCAST - 1]),
431 		       dev->addr_len);
432 		send_addr_notify = 1;
433 	}
434 
435 	if (ida[IFLA_MTU - 1]) {
436 		if (ida[IFLA_MTU - 1]->rta_len != RTA_LENGTH(sizeof(u32)))
437 			goto out;
438 		err = dev_set_mtu(dev, *((u32 *) RTA_DATA(ida[IFLA_MTU - 1])));
439 
440 		if (err)
441 			goto out;
442 
443 	}
444 
445 	if (ida[IFLA_TXQLEN - 1]) {
446 		if (ida[IFLA_TXQLEN - 1]->rta_len != RTA_LENGTH(sizeof(u32)))
447 			goto out;
448 
449 		dev->tx_queue_len = *((u32 *) RTA_DATA(ida[IFLA_TXQLEN - 1]));
450 	}
451 
452 	if (ida[IFLA_WEIGHT - 1]) {
453 		if (ida[IFLA_WEIGHT - 1]->rta_len != RTA_LENGTH(sizeof(u32)))
454 			goto out;
455 
456 		dev->weight = *((u32 *) RTA_DATA(ida[IFLA_WEIGHT - 1]));
457 	}
458 
459 	if (ida[IFLA_OPERSTATE - 1]) {
460 		if (ida[IFLA_OPERSTATE - 1]->rta_len != RTA_LENGTH(sizeof(u8)))
461 			goto out;
462 
463 		set_operstate(dev, *((u8 *) RTA_DATA(ida[IFLA_OPERSTATE - 1])));
464 	}
465 
466 	if (ida[IFLA_LINKMODE - 1]) {
467 		if (ida[IFLA_LINKMODE - 1]->rta_len != RTA_LENGTH(sizeof(u8)))
468 			goto out;
469 
470 		write_lock_bh(&dev_base_lock);
471 		dev->link_mode = *((u8 *) RTA_DATA(ida[IFLA_LINKMODE - 1]));
472 		write_unlock_bh(&dev_base_lock);
473 	}
474 
475 	if (ifm->ifi_index >= 0 && ida[IFLA_IFNAME - 1]) {
476 		char ifname[IFNAMSIZ];
477 
478 		if (rtattr_strlcpy(ifname, ida[IFLA_IFNAME - 1],
479 		                   IFNAMSIZ) >= IFNAMSIZ)
480 			goto out;
481 		err = dev_change_name(dev, ifname);
482 		if (err)
483 			goto out;
484 	}
485 
486 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
487 	if (ida[IFLA_WIRELESS - 1]) {
488 
489 		/* Call Wireless Extensions.
490 		 * Various stuff checked in there... */
491 		err = wireless_rtnetlink_set(dev, RTA_DATA(ida[IFLA_WIRELESS - 1]), ida[IFLA_WIRELESS - 1]->rta_len);
492 		if (err)
493 			goto out;
494 	}
495 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
496 
497 	err = 0;
498 
499 out:
500 	if (send_addr_notify)
501 		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
502 
503 	dev_put(dev);
504 	return err;
505 }
506 
507 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
508 static int do_getlink(struct sk_buff *in_skb, struct nlmsghdr* in_nlh, void *arg)
509 {
510 	struct ifinfomsg  *ifm = NLMSG_DATA(in_nlh);
511 	struct rtattr    **ida = arg;
512 	struct net_device *dev;
513 	struct ifinfomsg *r;
514 	struct nlmsghdr  *nlh;
515 	int err = -ENOBUFS;
516 	struct sk_buff *skb;
517 	unsigned char	 *b;
518 	char *iw_buf = NULL;
519 	int iw_buf_len = 0;
520 
521 	if (ifm->ifi_index >= 0)
522 		dev = dev_get_by_index(ifm->ifi_index);
523 	else
524 		return -EINVAL;
525 	if (!dev)
526 		return -ENODEV;
527 
528 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
529 	if (ida[IFLA_WIRELESS - 1]) {
530 
531 		/* Call Wireless Extensions. We need to know the size before
532 		 * we can alloc. Various stuff checked in there... */
533 		err = wireless_rtnetlink_get(dev, RTA_DATA(ida[IFLA_WIRELESS - 1]), ida[IFLA_WIRELESS - 1]->rta_len, &iw_buf, &iw_buf_len);
534 		if (err)
535 			goto out;
536 	}
537 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
538 
539 	/* Create a skb big enough to include all the data.
540 	 * Some requests are way bigger than 4k... Jean II */
541 	skb = alloc_skb((NLMSG_LENGTH(sizeof(*r))) + (RTA_SPACE(iw_buf_len)),
542 			GFP_KERNEL);
543 	if (!skb)
544 		goto out;
545 	b = skb->tail;
546 
547 	/* Put in the message the usual good stuff */
548 	nlh = NLMSG_PUT(skb, NETLINK_CB(in_skb).pid, in_nlh->nlmsg_seq,
549 			RTM_NEWLINK, sizeof(*r));
550 	r = NLMSG_DATA(nlh);
551 	r->ifi_family = AF_UNSPEC;
552 	r->__ifi_pad = 0;
553 	r->ifi_type = dev->type;
554 	r->ifi_index = dev->ifindex;
555 	r->ifi_flags = dev->flags;
556 	r->ifi_change = 0;
557 
558 	/* Put the wireless payload if it exist */
559 	if(iw_buf != NULL)
560 		RTA_PUT(skb, IFLA_WIRELESS, iw_buf_len,
561 			iw_buf + IW_EV_POINT_OFF);
562 
563 	nlh->nlmsg_len = skb->tail - b;
564 
565 	/* Needed ? */
566 	NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
567 
568 	err = netlink_unicast(rtnl, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
569 	if (err > 0)
570 		err = 0;
571 out:
572 	if(iw_buf != NULL)
573 		kfree(iw_buf);
574 	dev_put(dev);
575 	return err;
576 
577 rtattr_failure:
578 nlmsg_failure:
579 	kfree_skb(skb);
580 	goto out;
581 }
582 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
583 
584 static int rtnetlink_dump_all(struct sk_buff *skb, struct netlink_callback *cb)
585 {
586 	int idx;
587 	int s_idx = cb->family;
588 
589 	if (s_idx == 0)
590 		s_idx = 1;
591 	for (idx=1; idx<NPROTO; idx++) {
592 		int type = cb->nlh->nlmsg_type-RTM_BASE;
593 		if (idx < s_idx || idx == PF_PACKET)
594 			continue;
595 		if (rtnetlink_links[idx] == NULL ||
596 		    rtnetlink_links[idx][type].dumpit == NULL)
597 			continue;
598 		if (idx > s_idx)
599 			memset(&cb->args[0], 0, sizeof(cb->args));
600 		if (rtnetlink_links[idx][type].dumpit(skb, cb))
601 			break;
602 	}
603 	cb->family = idx;
604 
605 	return skb->len;
606 }
607 
608 void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)
609 {
610 	struct sk_buff *skb;
611 	int size = NLMSG_SPACE(sizeof(struct ifinfomsg) +
612 			       sizeof(struct rtnl_link_ifmap) +
613 			       sizeof(struct rtnl_link_stats) + 128);
614 
615 	skb = alloc_skb(size, GFP_KERNEL);
616 	if (!skb)
617 		return;
618 
619 	if (rtnetlink_fill_ifinfo(skb, dev, type, 0, 0, change, 0) < 0) {
620 		kfree_skb(skb);
621 		return;
622 	}
623 	NETLINK_CB(skb).dst_group = RTNLGRP_LINK;
624 	netlink_broadcast(rtnl, skb, 0, RTNLGRP_LINK, GFP_KERNEL);
625 }
626 
627 /* Protected by RTNL sempahore.  */
628 static struct rtattr **rta_buf;
629 static int rtattr_max;
630 
631 /* Process one rtnetlink message. */
632 
633 static __inline__ int
634 rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
635 {
636 	struct rtnetlink_link *link;
637 	struct rtnetlink_link *link_tab;
638 	int sz_idx, kind;
639 	int min_len;
640 	int family;
641 	int type;
642 	int err;
643 
644 	/* Only requests are handled by kernel now */
645 	if (!(nlh->nlmsg_flags&NLM_F_REQUEST))
646 		return 0;
647 
648 	type = nlh->nlmsg_type;
649 
650 	/* A control message: ignore them */
651 	if (type < RTM_BASE)
652 		return 0;
653 
654 	/* Unknown message: reply with EINVAL */
655 	if (type > RTM_MAX)
656 		goto err_inval;
657 
658 	type -= RTM_BASE;
659 
660 	/* All the messages must have at least 1 byte length */
661 	if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct rtgenmsg)))
662 		return 0;
663 
664 	family = ((struct rtgenmsg*)NLMSG_DATA(nlh))->rtgen_family;
665 	if (family >= NPROTO) {
666 		*errp = -EAFNOSUPPORT;
667 		return -1;
668 	}
669 
670 	link_tab = rtnetlink_links[family];
671 	if (link_tab == NULL)
672 		link_tab = rtnetlink_links[PF_UNSPEC];
673 	link = &link_tab[type];
674 
675 	sz_idx = type>>2;
676 	kind = type&3;
677 
678 	if (kind != 2 && security_netlink_recv(skb, CAP_NET_ADMIN)) {
679 		*errp = -EPERM;
680 		return -1;
681 	}
682 
683 	if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
684 		if (link->dumpit == NULL)
685 			link = &(rtnetlink_links[PF_UNSPEC][type]);
686 
687 		if (link->dumpit == NULL)
688 			goto err_inval;
689 
690 		if ((*errp = netlink_dump_start(rtnl, skb, nlh,
691 						link->dumpit, NULL)) != 0) {
692 			return -1;
693 		}
694 
695 		netlink_queue_skip(nlh, skb);
696 		return -1;
697 	}
698 
699 	memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *)));
700 
701 	min_len = rtm_min[sz_idx];
702 	if (nlh->nlmsg_len < min_len)
703 		goto err_inval;
704 
705 	if (nlh->nlmsg_len > min_len) {
706 		int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
707 		struct rtattr *attr = (void*)nlh + NLMSG_ALIGN(min_len);
708 
709 		while (RTA_OK(attr, attrlen)) {
710 			unsigned flavor = attr->rta_type;
711 			if (flavor) {
712 				if (flavor > rta_max[sz_idx])
713 					goto err_inval;
714 				rta_buf[flavor-1] = attr;
715 			}
716 			attr = RTA_NEXT(attr, attrlen);
717 		}
718 	}
719 
720 	if (link->doit == NULL)
721 		link = &(rtnetlink_links[PF_UNSPEC][type]);
722 	if (link->doit == NULL)
723 		goto err_inval;
724 	err = link->doit(skb, nlh, (void *)&rta_buf[0]);
725 
726 	*errp = err;
727 	return err;
728 
729 err_inval:
730 	*errp = -EINVAL;
731 	return -1;
732 }
733 
734 static void rtnetlink_rcv(struct sock *sk, int len)
735 {
736 	unsigned int qlen = 0;
737 
738 	do {
739 		mutex_lock(&rtnl_mutex);
740 		netlink_run_queue(sk, &qlen, &rtnetlink_rcv_msg);
741 		mutex_unlock(&rtnl_mutex);
742 
743 		netdev_run_todo();
744 	} while (qlen);
745 }
746 
747 static struct rtnetlink_link link_rtnetlink_table[RTM_NR_MSGTYPES] =
748 {
749 	[RTM_GETLINK     - RTM_BASE] = {
750 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
751 					 .doit   = do_getlink,
752 #endif	/* CONFIG_NET_WIRELESS_RTNETLINK */
753 					 .dumpit = rtnetlink_dump_ifinfo },
754 	[RTM_SETLINK     - RTM_BASE] = { .doit   = do_setlink		 },
755 	[RTM_GETADDR     - RTM_BASE] = { .dumpit = rtnetlink_dump_all	 },
756 	[RTM_GETROUTE    - RTM_BASE] = { .dumpit = rtnetlink_dump_all	 },
757 	[RTM_NEWNEIGH    - RTM_BASE] = { .doit   = neigh_add		 },
758 	[RTM_DELNEIGH    - RTM_BASE] = { .doit   = neigh_delete		 },
759 	[RTM_GETNEIGH    - RTM_BASE] = { .dumpit = neigh_dump_info	 },
760 	[RTM_GETRULE     - RTM_BASE] = { .dumpit = rtnetlink_dump_all	 },
761 	[RTM_GETNEIGHTBL - RTM_BASE] = { .dumpit = neightbl_dump_info	 },
762 	[RTM_SETNEIGHTBL - RTM_BASE] = { .doit   = neightbl_set		 },
763 };
764 
765 static int rtnetlink_event(struct notifier_block *this, unsigned long event, void *ptr)
766 {
767 	struct net_device *dev = ptr;
768 	switch (event) {
769 	case NETDEV_UNREGISTER:
770 		rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
771 		break;
772 	case NETDEV_REGISTER:
773 		rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U);
774 		break;
775 	case NETDEV_UP:
776 	case NETDEV_DOWN:
777 		rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);
778 		break;
779 	case NETDEV_CHANGE:
780 	case NETDEV_GOING_DOWN:
781 		break;
782 	default:
783 		rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
784 		break;
785 	}
786 	return NOTIFY_DONE;
787 }
788 
789 static struct notifier_block rtnetlink_dev_notifier = {
790 	.notifier_call	= rtnetlink_event,
791 };
792 
793 void __init rtnetlink_init(void)
794 {
795 	int i;
796 
797 	rtattr_max = 0;
798 	for (i = 0; i < ARRAY_SIZE(rta_max); i++)
799 		if (rta_max[i] > rtattr_max)
800 			rtattr_max = rta_max[i];
801 	rta_buf = kmalloc(rtattr_max * sizeof(struct rtattr *), GFP_KERNEL);
802 	if (!rta_buf)
803 		panic("rtnetlink_init: cannot allocate rta_buf\n");
804 
805 	rtnl = netlink_kernel_create(NETLINK_ROUTE, RTNLGRP_MAX, rtnetlink_rcv,
806 	                             THIS_MODULE);
807 	if (rtnl == NULL)
808 		panic("rtnetlink_init: cannot initialize rtnetlink\n");
809 	netlink_set_nonroot(NETLINK_ROUTE, NL_NONROOT_RECV);
810 	register_netdevice_notifier(&rtnetlink_dev_notifier);
811 	rtnetlink_links[PF_UNSPEC] = link_rtnetlink_table;
812 	rtnetlink_links[PF_PACKET] = link_rtnetlink_table;
813 }
814 
815 EXPORT_SYMBOL(__rta_fill);
816 EXPORT_SYMBOL(rtattr_strlcpy);
817 EXPORT_SYMBOL(rtattr_parse);
818 EXPORT_SYMBOL(rtnetlink_links);
819 EXPORT_SYMBOL(rtnetlink_put_metrics);
820 EXPORT_SYMBOL(rtnl);
821 EXPORT_SYMBOL(rtnl_lock);
822 EXPORT_SYMBOL(rtnl_trylock);
823 EXPORT_SYMBOL(rtnl_unlock);
824