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ipv6: fix possible use after free of dev stats
[deliverable/linux.git] / net / mpls / af_mpls.c
1 #include <linux/types.h>
2 #include <linux/skbuff.h>
3 #include <linux/socket.h>
4 #include <linux/sysctl.h>
5 #include <linux/net.h>
6 #include <linux/module.h>
7 #include <linux/if_arp.h>
8 #include <linux/ipv6.h>
9 #include <linux/mpls.h>
10 #include <linux/vmalloc.h>
11 #include <net/ip.h>
12 #include <net/dst.h>
13 #include <net/sock.h>
14 #include <net/arp.h>
15 #include <net/ip_fib.h>
16 #include <net/netevent.h>
17 #include <net/netns/generic.h>
18 #include "internal.h"
19
20 #define LABEL_NOT_SPECIFIED (1<<20)
21 #define MAX_NEW_LABELS 2
22
23 /* This maximum ha length copied from the definition of struct neighbour */
24 #define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))
25
26 struct mpls_route { /* next hop label forwarding entry */
27 struct net_device __rcu *rt_dev;
28 struct rcu_head rt_rcu;
29 u32 rt_label[MAX_NEW_LABELS];
30 u8 rt_protocol; /* routing protocol that set this entry */
31 u8 rt_labels;
32 u8 rt_via_alen;
33 u8 rt_via_table;
34 u8 rt_via[0];
35 };
36
37 static int zero = 0;
38 static int label_limit = (1 << 20) - 1;
39
40 static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
41 struct nlmsghdr *nlh, struct net *net, u32 portid,
42 unsigned int nlm_flags);
43
44 static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned index)
45 {
46 struct mpls_route *rt = NULL;
47
48 if (index < net->mpls.platform_labels) {
49 struct mpls_route __rcu **platform_label =
50 rcu_dereference(net->mpls.platform_label);
51 rt = rcu_dereference(platform_label[index]);
52 }
53 return rt;
54 }
55
56 static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
57 {
58 return rcu_dereference_rtnl(dev->mpls_ptr);
59 }
60
61 static bool mpls_output_possible(const struct net_device *dev)
62 {
63 return dev && (dev->flags & IFF_UP) && netif_carrier_ok(dev);
64 }
65
66 static unsigned int mpls_rt_header_size(const struct mpls_route *rt)
67 {
68 /* The size of the layer 2.5 labels to be added for this route */
69 return rt->rt_labels * sizeof(struct mpls_shim_hdr);
70 }
71
72 static unsigned int mpls_dev_mtu(const struct net_device *dev)
73 {
74 /* The amount of data the layer 2 frame can hold */
75 return dev->mtu;
76 }
77
78 static bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
79 {
80 if (skb->len <= mtu)
81 return false;
82
83 if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)
84 return false;
85
86 return true;
87 }
88
89 static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
90 struct mpls_entry_decoded dec)
91 {
92 /* RFC4385 and RFC5586 encode other packets in mpls such that
93 * they don't conflict with the ip version number, making
94 * decoding by examining the ip version correct in everything
95 * except for the strangest cases.
96 *
97 * The strange cases if we choose to support them will require
98 * manual configuration.
99 */
100 struct iphdr *hdr4;
101 bool success = true;
102
103 /* The IPv4 code below accesses through the IPv4 header
104 * checksum, which is 12 bytes into the packet.
105 * The IPv6 code below accesses through the IPv6 hop limit
106 * which is 8 bytes into the packet.
107 *
108 * For all supported cases there should always be at least 12
109 * bytes of packet data present. The IPv4 header is 20 bytes
110 * without options and the IPv6 header is always 40 bytes
111 * long.
112 */
113 if (!pskb_may_pull(skb, 12))
114 return false;
115
116 /* Use ip_hdr to find the ip protocol version */
117 hdr4 = ip_hdr(skb);
118 if (hdr4->version == 4) {
119 skb->protocol = htons(ETH_P_IP);
120 csum_replace2(&hdr4->check,
121 htons(hdr4->ttl << 8),
122 htons(dec.ttl << 8));
123 hdr4->ttl = dec.ttl;
124 }
125 else if (hdr4->version == 6) {
126 struct ipv6hdr *hdr6 = ipv6_hdr(skb);
127 skb->protocol = htons(ETH_P_IPV6);
128 hdr6->hop_limit = dec.ttl;
129 }
130 else
131 /* version 0 and version 1 are used by pseudo wires */
132 success = false;
133 return success;
134 }
135
136 static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
137 struct packet_type *pt, struct net_device *orig_dev)
138 {
139 struct net *net = dev_net(dev);
140 struct mpls_shim_hdr *hdr;
141 struct mpls_route *rt;
142 struct mpls_entry_decoded dec;
143 struct net_device *out_dev;
144 struct mpls_dev *mdev;
145 unsigned int hh_len;
146 unsigned int new_header_size;
147 unsigned int mtu;
148 int err;
149
150 /* Careful this entire function runs inside of an rcu critical section */
151
152 mdev = mpls_dev_get(dev);
153 if (!mdev || !mdev->input_enabled)
154 goto drop;
155
156 if (skb->pkt_type != PACKET_HOST)
157 goto drop;
158
159 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
160 goto drop;
161
162 if (!pskb_may_pull(skb, sizeof(*hdr)))
163 goto drop;
164
165 /* Read and decode the label */
166 hdr = mpls_hdr(skb);
167 dec = mpls_entry_decode(hdr);
168
169 /* Pop the label */
170 skb_pull(skb, sizeof(*hdr));
171 skb_reset_network_header(skb);
172
173 skb_orphan(skb);
174
175 rt = mpls_route_input_rcu(net, dec.label);
176 if (!rt)
177 goto drop;
178
179 /* Find the output device */
180 out_dev = rcu_dereference(rt->rt_dev);
181 if (!mpls_output_possible(out_dev))
182 goto drop;
183
184 if (skb_warn_if_lro(skb))
185 goto drop;
186
187 skb_forward_csum(skb);
188
189 /* Verify ttl is valid */
190 if (dec.ttl <= 1)
191 goto drop;
192 dec.ttl -= 1;
193
194 /* Verify the destination can hold the packet */
195 new_header_size = mpls_rt_header_size(rt);
196 mtu = mpls_dev_mtu(out_dev);
197 if (mpls_pkt_too_big(skb, mtu - new_header_size))
198 goto drop;
199
200 hh_len = LL_RESERVED_SPACE(out_dev);
201 if (!out_dev->header_ops)
202 hh_len = 0;
203
204 /* Ensure there is enough space for the headers in the skb */
205 if (skb_cow(skb, hh_len + new_header_size))
206 goto drop;
207
208 skb->dev = out_dev;
209 skb->protocol = htons(ETH_P_MPLS_UC);
210
211 if (unlikely(!new_header_size && dec.bos)) {
212 /* Penultimate hop popping */
213 if (!mpls_egress(rt, skb, dec))
214 goto drop;
215 } else {
216 bool bos;
217 int i;
218 skb_push(skb, new_header_size);
219 skb_reset_network_header(skb);
220 /* Push the new labels */
221 hdr = mpls_hdr(skb);
222 bos = dec.bos;
223 for (i = rt->rt_labels - 1; i >= 0; i--) {
224 hdr[i] = mpls_entry_encode(rt->rt_label[i], dec.ttl, 0, bos);
225 bos = false;
226 }
227 }
228
229 err = neigh_xmit(rt->rt_via_table, out_dev, rt->rt_via, skb);
230 if (err)
231 net_dbg_ratelimited("%s: packet transmission failed: %d\n",
232 __func__, err);
233 return 0;
234
235 drop:
236 kfree_skb(skb);
237 return NET_RX_DROP;
238 }
239
240 static struct packet_type mpls_packet_type __read_mostly = {
241 .type = cpu_to_be16(ETH_P_MPLS_UC),
242 .func = mpls_forward,
243 };
244
245 static const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = {
246 [RTA_DST] = { .type = NLA_U32 },
247 [RTA_OIF] = { .type = NLA_U32 },
248 };
249
250 struct mpls_route_config {
251 u32 rc_protocol;
252 u32 rc_ifindex;
253 u16 rc_via_table;
254 u16 rc_via_alen;
255 u8 rc_via[MAX_VIA_ALEN];
256 u32 rc_label;
257 u32 rc_output_labels;
258 u32 rc_output_label[MAX_NEW_LABELS];
259 u32 rc_nlflags;
260 struct nl_info rc_nlinfo;
261 };
262
263 static struct mpls_route *mpls_rt_alloc(size_t alen)
264 {
265 struct mpls_route *rt;
266
267 rt = kzalloc(sizeof(*rt) + alen, GFP_KERNEL);
268 if (rt)
269 rt->rt_via_alen = alen;
270 return rt;
271 }
272
273 static void mpls_rt_free(struct mpls_route *rt)
274 {
275 if (rt)
276 kfree_rcu(rt, rt_rcu);
277 }
278
279 static void mpls_notify_route(struct net *net, unsigned index,
280 struct mpls_route *old, struct mpls_route *new,
281 const struct nl_info *info)
282 {
283 struct nlmsghdr *nlh = info ? info->nlh : NULL;
284 unsigned portid = info ? info->portid : 0;
285 int event = new ? RTM_NEWROUTE : RTM_DELROUTE;
286 struct mpls_route *rt = new ? new : old;
287 unsigned nlm_flags = (old && new) ? NLM_F_REPLACE : 0;
288 /* Ignore reserved labels for now */
289 if (rt && (index >= 16))
290 rtmsg_lfib(event, index, rt, nlh, net, portid, nlm_flags);
291 }
292
293 static void mpls_route_update(struct net *net, unsigned index,
294 struct net_device *dev, struct mpls_route *new,
295 const struct nl_info *info)
296 {
297 struct mpls_route __rcu **platform_label;
298 struct mpls_route *rt, *old = NULL;
299
300 ASSERT_RTNL();
301
302 platform_label = rtnl_dereference(net->mpls.platform_label);
303 rt = rtnl_dereference(platform_label[index]);
304 if (!dev || (rt && (rtnl_dereference(rt->rt_dev) == dev))) {
305 rcu_assign_pointer(platform_label[index], new);
306 old = rt;
307 }
308
309 mpls_notify_route(net, index, old, new, info);
310
311 /* If we removed a route free it now */
312 mpls_rt_free(old);
313 }
314
315 static unsigned find_free_label(struct net *net)
316 {
317 struct mpls_route __rcu **platform_label;
318 size_t platform_labels;
319 unsigned index;
320
321 platform_label = rtnl_dereference(net->mpls.platform_label);
322 platform_labels = net->mpls.platform_labels;
323 for (index = 16; index < platform_labels; index++) {
324 if (!rtnl_dereference(platform_label[index]))
325 return index;
326 }
327 return LABEL_NOT_SPECIFIED;
328 }
329
330 static int mpls_route_add(struct mpls_route_config *cfg)
331 {
332 struct mpls_route __rcu **platform_label;
333 struct net *net = cfg->rc_nlinfo.nl_net;
334 struct net_device *dev = NULL;
335 struct mpls_route *rt, *old;
336 unsigned index;
337 int i;
338 int err = -EINVAL;
339
340 index = cfg->rc_label;
341
342 /* If a label was not specified during insert pick one */
343 if ((index == LABEL_NOT_SPECIFIED) &&
344 (cfg->rc_nlflags & NLM_F_CREATE)) {
345 index = find_free_label(net);
346 }
347
348 /* The first 16 labels are reserved, and may not be set */
349 if (index < 16)
350 goto errout;
351
352 /* The full 20 bit range may not be supported. */
353 if (index >= net->mpls.platform_labels)
354 goto errout;
355
356 /* Ensure only a supported number of labels are present */
357 if (cfg->rc_output_labels > MAX_NEW_LABELS)
358 goto errout;
359
360 err = -ENODEV;
361 dev = dev_get_by_index(net, cfg->rc_ifindex);
362 if (!dev)
363 goto errout;
364
365 /* Ensure this is a supported device */
366 err = -EINVAL;
367 if (!mpls_dev_get(dev))
368 goto errout;
369
370 err = -EINVAL;
371 if ((cfg->rc_via_table == NEIGH_LINK_TABLE) &&
372 (dev->addr_len != cfg->rc_via_alen))
373 goto errout;
374
375 /* Append makes no sense with mpls */
376 err = -EOPNOTSUPP;
377 if (cfg->rc_nlflags & NLM_F_APPEND)
378 goto errout;
379
380 err = -EEXIST;
381 platform_label = rtnl_dereference(net->mpls.platform_label);
382 old = rtnl_dereference(platform_label[index]);
383 if ((cfg->rc_nlflags & NLM_F_EXCL) && old)
384 goto errout;
385
386 err = -EEXIST;
387 if (!(cfg->rc_nlflags & NLM_F_REPLACE) && old)
388 goto errout;
389
390 err = -ENOENT;
391 if (!(cfg->rc_nlflags & NLM_F_CREATE) && !old)
392 goto errout;
393
394 err = -ENOMEM;
395 rt = mpls_rt_alloc(cfg->rc_via_alen);
396 if (!rt)
397 goto errout;
398
399 rt->rt_labels = cfg->rc_output_labels;
400 for (i = 0; i < rt->rt_labels; i++)
401 rt->rt_label[i] = cfg->rc_output_label[i];
402 rt->rt_protocol = cfg->rc_protocol;
403 RCU_INIT_POINTER(rt->rt_dev, dev);
404 rt->rt_via_table = cfg->rc_via_table;
405 memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen);
406
407 mpls_route_update(net, index, NULL, rt, &cfg->rc_nlinfo);
408
409 dev_put(dev);
410 return 0;
411
412 errout:
413 if (dev)
414 dev_put(dev);
415 return err;
416 }
417
418 static int mpls_route_del(struct mpls_route_config *cfg)
419 {
420 struct net *net = cfg->rc_nlinfo.nl_net;
421 unsigned index;
422 int err = -EINVAL;
423
424 index = cfg->rc_label;
425
426 /* The first 16 labels are reserved, and may not be removed */
427 if (index < 16)
428 goto errout;
429
430 /* The full 20 bit range may not be supported */
431 if (index >= net->mpls.platform_labels)
432 goto errout;
433
434 mpls_route_update(net, index, NULL, NULL, &cfg->rc_nlinfo);
435
436 err = 0;
437 errout:
438 return err;
439 }
440
441 #define MPLS_PERDEV_SYSCTL_OFFSET(field) \
442 (&((struct mpls_dev *)0)->field)
443
444 static const struct ctl_table mpls_dev_table[] = {
445 {
446 .procname = "input",
447 .maxlen = sizeof(int),
448 .mode = 0644,
449 .proc_handler = proc_dointvec,
450 .data = MPLS_PERDEV_SYSCTL_OFFSET(input_enabled),
451 },
452 { }
453 };
454
455 static int mpls_dev_sysctl_register(struct net_device *dev,
456 struct mpls_dev *mdev)
457 {
458 char path[sizeof("net/mpls/conf/") + IFNAMSIZ];
459 struct ctl_table *table;
460 int i;
461
462 table = kmemdup(&mpls_dev_table, sizeof(mpls_dev_table), GFP_KERNEL);
463 if (!table)
464 goto out;
465
466 /* Table data contains only offsets relative to the base of
467 * the mdev at this point, so make them absolute.
468 */
469 for (i = 0; i < ARRAY_SIZE(mpls_dev_table); i++)
470 table[i].data = (char *)mdev + (uintptr_t)table[i].data;
471
472 snprintf(path, sizeof(path), "net/mpls/conf/%s", dev->name);
473
474 mdev->sysctl = register_net_sysctl(dev_net(dev), path, table);
475 if (!mdev->sysctl)
476 goto free;
477
478 return 0;
479
480 free:
481 kfree(table);
482 out:
483 return -ENOBUFS;
484 }
485
486 static void mpls_dev_sysctl_unregister(struct mpls_dev *mdev)
487 {
488 struct ctl_table *table;
489
490 table = mdev->sysctl->ctl_table_arg;
491 unregister_net_sysctl_table(mdev->sysctl);
492 kfree(table);
493 }
494
495 static struct mpls_dev *mpls_add_dev(struct net_device *dev)
496 {
497 struct mpls_dev *mdev;
498 int err = -ENOMEM;
499
500 ASSERT_RTNL();
501
502 mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
503 if (!mdev)
504 return ERR_PTR(err);
505
506 err = mpls_dev_sysctl_register(dev, mdev);
507 if (err)
508 goto free;
509
510 rcu_assign_pointer(dev->mpls_ptr, mdev);
511
512 return mdev;
513
514 free:
515 kfree(mdev);
516 return ERR_PTR(err);
517 }
518
519 static void mpls_ifdown(struct net_device *dev)
520 {
521 struct mpls_route __rcu **platform_label;
522 struct net *net = dev_net(dev);
523 struct mpls_dev *mdev;
524 unsigned index;
525
526 platform_label = rtnl_dereference(net->mpls.platform_label);
527 for (index = 0; index < net->mpls.platform_labels; index++) {
528 struct mpls_route *rt = rtnl_dereference(platform_label[index]);
529 if (!rt)
530 continue;
531 if (rtnl_dereference(rt->rt_dev) != dev)
532 continue;
533 rt->rt_dev = NULL;
534 }
535
536 mdev = mpls_dev_get(dev);
537 if (!mdev)
538 return;
539
540 mpls_dev_sysctl_unregister(mdev);
541
542 RCU_INIT_POINTER(dev->mpls_ptr, NULL);
543
544 kfree_rcu(mdev, rcu);
545 }
546
547 static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
548 void *ptr)
549 {
550 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
551 struct mpls_dev *mdev;
552
553 switch(event) {
554 case NETDEV_REGISTER:
555 /* For now just support ethernet devices */
556 if ((dev->type == ARPHRD_ETHER) ||
557 (dev->type == ARPHRD_LOOPBACK)) {
558 mdev = mpls_add_dev(dev);
559 if (IS_ERR(mdev))
560 return notifier_from_errno(PTR_ERR(mdev));
561 }
562 break;
563
564 case NETDEV_UNREGISTER:
565 mpls_ifdown(dev);
566 break;
567 }
568 return NOTIFY_OK;
569 }
570
571 static struct notifier_block mpls_dev_notifier = {
572 .notifier_call = mpls_dev_notify,
573 };
574
575 static int nla_put_via(struct sk_buff *skb,
576 u8 table, const void *addr, int alen)
577 {
578 static const int table_to_family[NEIGH_NR_TABLES + 1] = {
579 AF_INET, AF_INET6, AF_DECnet, AF_PACKET,
580 };
581 struct nlattr *nla;
582 struct rtvia *via;
583 int family = AF_UNSPEC;
584
585 nla = nla_reserve(skb, RTA_VIA, alen + 2);
586 if (!nla)
587 return -EMSGSIZE;
588
589 if (table <= NEIGH_NR_TABLES)
590 family = table_to_family[table];
591
592 via = nla_data(nla);
593 via->rtvia_family = family;
594 memcpy(via->rtvia_addr, addr, alen);
595 return 0;
596 }
597
598 int nla_put_labels(struct sk_buff *skb, int attrtype,
599 u8 labels, const u32 label[])
600 {
601 struct nlattr *nla;
602 struct mpls_shim_hdr *nla_label;
603 bool bos;
604 int i;
605 nla = nla_reserve(skb, attrtype, labels*4);
606 if (!nla)
607 return -EMSGSIZE;
608
609 nla_label = nla_data(nla);
610 bos = true;
611 for (i = labels - 1; i >= 0; i--) {
612 nla_label[i] = mpls_entry_encode(label[i], 0, 0, bos);
613 bos = false;
614 }
615
616 return 0;
617 }
618
619 int nla_get_labels(const struct nlattr *nla,
620 u32 max_labels, u32 *labels, u32 label[])
621 {
622 unsigned len = nla_len(nla);
623 unsigned nla_labels;
624 struct mpls_shim_hdr *nla_label;
625 bool bos;
626 int i;
627
628 /* len needs to be an even multiple of 4 (the label size) */
629 if (len & 3)
630 return -EINVAL;
631
632 /* Limit the number of new labels allowed */
633 nla_labels = len/4;
634 if (nla_labels > max_labels)
635 return -EINVAL;
636
637 nla_label = nla_data(nla);
638 bos = true;
639 for (i = nla_labels - 1; i >= 0; i--, bos = false) {
640 struct mpls_entry_decoded dec;
641 dec = mpls_entry_decode(nla_label + i);
642
643 /* Ensure the bottom of stack flag is properly set
644 * and ttl and tc are both clear.
645 */
646 if ((dec.bos != bos) || dec.ttl || dec.tc)
647 return -EINVAL;
648
649 switch (dec.label) {
650 case MPLS_LABEL_IMPLNULL:
651 /* RFC3032: This is a label that an LSR may
652 * assign and distribute, but which never
653 * actually appears in the encapsulation.
654 */
655 return -EINVAL;
656 }
657
658 label[i] = dec.label;
659 }
660 *labels = nla_labels;
661 return 0;
662 }
663
664 static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
665 struct mpls_route_config *cfg)
666 {
667 struct rtmsg *rtm;
668 struct nlattr *tb[RTA_MAX+1];
669 int index;
670 int err;
671
672 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_mpls_policy);
673 if (err < 0)
674 goto errout;
675
676 err = -EINVAL;
677 rtm = nlmsg_data(nlh);
678 memset(cfg, 0, sizeof(*cfg));
679
680 if (rtm->rtm_family != AF_MPLS)
681 goto errout;
682 if (rtm->rtm_dst_len != 20)
683 goto errout;
684 if (rtm->rtm_src_len != 0)
685 goto errout;
686 if (rtm->rtm_tos != 0)
687 goto errout;
688 if (rtm->rtm_table != RT_TABLE_MAIN)
689 goto errout;
690 /* Any value is acceptable for rtm_protocol */
691
692 /* As mpls uses destination specific addresses
693 * (or source specific address in the case of multicast)
694 * all addresses have universal scope.
695 */
696 if (rtm->rtm_scope != RT_SCOPE_UNIVERSE)
697 goto errout;
698 if (rtm->rtm_type != RTN_UNICAST)
699 goto errout;
700 if (rtm->rtm_flags != 0)
701 goto errout;
702
703 cfg->rc_label = LABEL_NOT_SPECIFIED;
704 cfg->rc_protocol = rtm->rtm_protocol;
705 cfg->rc_nlflags = nlh->nlmsg_flags;
706 cfg->rc_nlinfo.portid = NETLINK_CB(skb).portid;
707 cfg->rc_nlinfo.nlh = nlh;
708 cfg->rc_nlinfo.nl_net = sock_net(skb->sk);
709
710 for (index = 0; index <= RTA_MAX; index++) {
711 struct nlattr *nla = tb[index];
712 if (!nla)
713 continue;
714
715 switch(index) {
716 case RTA_OIF:
717 cfg->rc_ifindex = nla_get_u32(nla);
718 break;
719 case RTA_NEWDST:
720 if (nla_get_labels(nla, MAX_NEW_LABELS,
721 &cfg->rc_output_labels,
722 cfg->rc_output_label))
723 goto errout;
724 break;
725 case RTA_DST:
726 {
727 u32 label_count;
728 if (nla_get_labels(nla, 1, &label_count,
729 &cfg->rc_label))
730 goto errout;
731
732 /* The first 16 labels are reserved, and may not be set */
733 if (cfg->rc_label < 16)
734 goto errout;
735
736 break;
737 }
738 case RTA_VIA:
739 {
740 struct rtvia *via = nla_data(nla);
741 if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
742 goto errout;
743 cfg->rc_via_alen = nla_len(nla) -
744 offsetof(struct rtvia, rtvia_addr);
745 if (cfg->rc_via_alen > MAX_VIA_ALEN)
746 goto errout;
747
748 /* Validate the address family */
749 switch(via->rtvia_family) {
750 case AF_PACKET:
751 cfg->rc_via_table = NEIGH_LINK_TABLE;
752 break;
753 case AF_INET:
754 cfg->rc_via_table = NEIGH_ARP_TABLE;
755 if (cfg->rc_via_alen != 4)
756 goto errout;
757 break;
758 case AF_INET6:
759 cfg->rc_via_table = NEIGH_ND_TABLE;
760 if (cfg->rc_via_alen != 16)
761 goto errout;
762 break;
763 default:
764 /* Unsupported address family */
765 goto errout;
766 }
767
768 memcpy(cfg->rc_via, via->rtvia_addr, cfg->rc_via_alen);
769 break;
770 }
771 default:
772 /* Unsupported attribute */
773 goto errout;
774 }
775 }
776
777 err = 0;
778 errout:
779 return err;
780 }
781
782 static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
783 {
784 struct mpls_route_config cfg;
785 int err;
786
787 err = rtm_to_route_config(skb, nlh, &cfg);
788 if (err < 0)
789 return err;
790
791 return mpls_route_del(&cfg);
792 }
793
794
795 static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
796 {
797 struct mpls_route_config cfg;
798 int err;
799
800 err = rtm_to_route_config(skb, nlh, &cfg);
801 if (err < 0)
802 return err;
803
804 return mpls_route_add(&cfg);
805 }
806
807 static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
808 u32 label, struct mpls_route *rt, int flags)
809 {
810 struct net_device *dev;
811 struct nlmsghdr *nlh;
812 struct rtmsg *rtm;
813
814 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
815 if (nlh == NULL)
816 return -EMSGSIZE;
817
818 rtm = nlmsg_data(nlh);
819 rtm->rtm_family = AF_MPLS;
820 rtm->rtm_dst_len = 20;
821 rtm->rtm_src_len = 0;
822 rtm->rtm_tos = 0;
823 rtm->rtm_table = RT_TABLE_MAIN;
824 rtm->rtm_protocol = rt->rt_protocol;
825 rtm->rtm_scope = RT_SCOPE_UNIVERSE;
826 rtm->rtm_type = RTN_UNICAST;
827 rtm->rtm_flags = 0;
828
829 if (rt->rt_labels &&
830 nla_put_labels(skb, RTA_NEWDST, rt->rt_labels, rt->rt_label))
831 goto nla_put_failure;
832 if (nla_put_via(skb, rt->rt_via_table, rt->rt_via, rt->rt_via_alen))
833 goto nla_put_failure;
834 dev = rtnl_dereference(rt->rt_dev);
835 if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
836 goto nla_put_failure;
837 if (nla_put_labels(skb, RTA_DST, 1, &label))
838 goto nla_put_failure;
839
840 nlmsg_end(skb, nlh);
841 return 0;
842
843 nla_put_failure:
844 nlmsg_cancel(skb, nlh);
845 return -EMSGSIZE;
846 }
847
848 static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
849 {
850 struct net *net = sock_net(skb->sk);
851 struct mpls_route __rcu **platform_label;
852 size_t platform_labels;
853 unsigned int index;
854
855 ASSERT_RTNL();
856
857 index = cb->args[0];
858 if (index < 16)
859 index = 16;
860
861 platform_label = rtnl_dereference(net->mpls.platform_label);
862 platform_labels = net->mpls.platform_labels;
863 for (; index < platform_labels; index++) {
864 struct mpls_route *rt;
865 rt = rtnl_dereference(platform_label[index]);
866 if (!rt)
867 continue;
868
869 if (mpls_dump_route(skb, NETLINK_CB(cb->skb).portid,
870 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
871 index, rt, NLM_F_MULTI) < 0)
872 break;
873 }
874 cb->args[0] = index;
875
876 return skb->len;
877 }
878
879 static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
880 {
881 size_t payload =
882 NLMSG_ALIGN(sizeof(struct rtmsg))
883 + nla_total_size(2 + rt->rt_via_alen) /* RTA_VIA */
884 + nla_total_size(4); /* RTA_DST */
885 if (rt->rt_labels) /* RTA_NEWDST */
886 payload += nla_total_size(rt->rt_labels * 4);
887 if (rt->rt_dev) /* RTA_OIF */
888 payload += nla_total_size(4);
889 return payload;
890 }
891
892 static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
893 struct nlmsghdr *nlh, struct net *net, u32 portid,
894 unsigned int nlm_flags)
895 {
896 struct sk_buff *skb;
897 u32 seq = nlh ? nlh->nlmsg_seq : 0;
898 int err = -ENOBUFS;
899
900 skb = nlmsg_new(lfib_nlmsg_size(rt), GFP_KERNEL);
901 if (skb == NULL)
902 goto errout;
903
904 err = mpls_dump_route(skb, portid, seq, event, label, rt, nlm_flags);
905 if (err < 0) {
906 /* -EMSGSIZE implies BUG in lfib_nlmsg_size */
907 WARN_ON(err == -EMSGSIZE);
908 kfree_skb(skb);
909 goto errout;
910 }
911 rtnl_notify(skb, net, portid, RTNLGRP_MPLS_ROUTE, nlh, GFP_KERNEL);
912
913 return;
914 errout:
915 if (err < 0)
916 rtnl_set_sk_err(net, RTNLGRP_MPLS_ROUTE, err);
917 }
918
919 static int resize_platform_label_table(struct net *net, size_t limit)
920 {
921 size_t size = sizeof(struct mpls_route *) * limit;
922 size_t old_limit;
923 size_t cp_size;
924 struct mpls_route __rcu **labels = NULL, **old;
925 struct mpls_route *rt0 = NULL, *rt2 = NULL;
926 unsigned index;
927
928 if (size) {
929 labels = kzalloc(size, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
930 if (!labels)
931 labels = vzalloc(size);
932
933 if (!labels)
934 goto nolabels;
935 }
936
937 /* In case the predefined labels need to be populated */
938 if (limit > MPLS_LABEL_IPV4NULL) {
939 struct net_device *lo = net->loopback_dev;
940 rt0 = mpls_rt_alloc(lo->addr_len);
941 if (!rt0)
942 goto nort0;
943 RCU_INIT_POINTER(rt0->rt_dev, lo);
944 rt0->rt_protocol = RTPROT_KERNEL;
945 rt0->rt_via_table = NEIGH_LINK_TABLE;
946 memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
947 }
948 if (limit > MPLS_LABEL_IPV6NULL) {
949 struct net_device *lo = net->loopback_dev;
950 rt2 = mpls_rt_alloc(lo->addr_len);
951 if (!rt2)
952 goto nort2;
953 RCU_INIT_POINTER(rt2->rt_dev, lo);
954 rt2->rt_protocol = RTPROT_KERNEL;
955 rt2->rt_via_table = NEIGH_LINK_TABLE;
956 memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
957 }
958
959 rtnl_lock();
960 /* Remember the original table */
961 old = rtnl_dereference(net->mpls.platform_label);
962 old_limit = net->mpls.platform_labels;
963
964 /* Free any labels beyond the new table */
965 for (index = limit; index < old_limit; index++)
966 mpls_route_update(net, index, NULL, NULL, NULL);
967
968 /* Copy over the old labels */
969 cp_size = size;
970 if (old_limit < limit)
971 cp_size = old_limit * sizeof(struct mpls_route *);
972
973 memcpy(labels, old, cp_size);
974
975 /* If needed set the predefined labels */
976 if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
977 (limit > MPLS_LABEL_IPV6NULL)) {
978 RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
979 rt2 = NULL;
980 }
981
982 if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
983 (limit > MPLS_LABEL_IPV4NULL)) {
984 RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
985 rt0 = NULL;
986 }
987
988 /* Update the global pointers */
989 net->mpls.platform_labels = limit;
990 rcu_assign_pointer(net->mpls.platform_label, labels);
991
992 rtnl_unlock();
993
994 mpls_rt_free(rt2);
995 mpls_rt_free(rt0);
996
997 if (old) {
998 synchronize_rcu();
999 kvfree(old);
1000 }
1001 return 0;
1002
1003 nort2:
1004 mpls_rt_free(rt0);
1005 nort0:
1006 kvfree(labels);
1007 nolabels:
1008 return -ENOMEM;
1009 }
1010
1011 static int mpls_platform_labels(struct ctl_table *table, int write,
1012 void __user *buffer, size_t *lenp, loff_t *ppos)
1013 {
1014 struct net *net = table->data;
1015 int platform_labels = net->mpls.platform_labels;
1016 int ret;
1017 struct ctl_table tmp = {
1018 .procname = table->procname,
1019 .data = &platform_labels,
1020 .maxlen = sizeof(int),
1021 .mode = table->mode,
1022 .extra1 = &zero,
1023 .extra2 = &label_limit,
1024 };
1025
1026 ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
1027
1028 if (write && ret == 0)
1029 ret = resize_platform_label_table(net, platform_labels);
1030
1031 return ret;
1032 }
1033
1034 static const struct ctl_table mpls_table[] = {
1035 {
1036 .procname = "platform_labels",
1037 .data = NULL,
1038 .maxlen = sizeof(int),
1039 .mode = 0644,
1040 .proc_handler = mpls_platform_labels,
1041 },
1042 { }
1043 };
1044
1045 static int mpls_net_init(struct net *net)
1046 {
1047 struct ctl_table *table;
1048
1049 net->mpls.platform_labels = 0;
1050 net->mpls.platform_label = NULL;
1051
1052 table = kmemdup(mpls_table, sizeof(mpls_table), GFP_KERNEL);
1053 if (table == NULL)
1054 return -ENOMEM;
1055
1056 table[0].data = net;
1057 net->mpls.ctl = register_net_sysctl(net, "net/mpls", table);
1058 if (net->mpls.ctl == NULL)
1059 return -ENOMEM;
1060
1061 return 0;
1062 }
1063
1064 static void mpls_net_exit(struct net *net)
1065 {
1066 struct mpls_route __rcu **platform_label;
1067 size_t platform_labels;
1068 struct ctl_table *table;
1069 unsigned int index;
1070
1071 table = net->mpls.ctl->ctl_table_arg;
1072 unregister_net_sysctl_table(net->mpls.ctl);
1073 kfree(table);
1074
1075 /* An rcu grace period has passed since there was a device in
1076 * the network namespace (and thus the last in flight packet)
1077 * left this network namespace. This is because
1078 * unregister_netdevice_many and netdev_run_todo has completed
1079 * for each network device that was in this network namespace.
1080 *
1081 * As such no additional rcu synchronization is necessary when
1082 * freeing the platform_label table.
1083 */
1084 rtnl_lock();
1085 platform_label = rtnl_dereference(net->mpls.platform_label);
1086 platform_labels = net->mpls.platform_labels;
1087 for (index = 0; index < platform_labels; index++) {
1088 struct mpls_route *rt = rtnl_dereference(platform_label[index]);
1089 RCU_INIT_POINTER(platform_label[index], NULL);
1090 mpls_rt_free(rt);
1091 }
1092 rtnl_unlock();
1093
1094 kvfree(platform_label);
1095 }
1096
1097 static struct pernet_operations mpls_net_ops = {
1098 .init = mpls_net_init,
1099 .exit = mpls_net_exit,
1100 };
1101
1102 static int __init mpls_init(void)
1103 {
1104 int err;
1105
1106 BUILD_BUG_ON(sizeof(struct mpls_shim_hdr) != 4);
1107
1108 err = register_pernet_subsys(&mpls_net_ops);
1109 if (err)
1110 goto out;
1111
1112 err = register_netdevice_notifier(&mpls_dev_notifier);
1113 if (err)
1114 goto out_unregister_pernet;
1115
1116 dev_add_pack(&mpls_packet_type);
1117
1118 rtnl_register(PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, NULL);
1119 rtnl_register(PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, NULL);
1120 rtnl_register(PF_MPLS, RTM_GETROUTE, NULL, mpls_dump_routes, NULL);
1121 err = 0;
1122 out:
1123 return err;
1124
1125 out_unregister_pernet:
1126 unregister_pernet_subsys(&mpls_net_ops);
1127 goto out;
1128 }
1129 module_init(mpls_init);
1130
1131 static void __exit mpls_exit(void)
1132 {
1133 rtnl_unregister_all(PF_MPLS);
1134 dev_remove_pack(&mpls_packet_type);
1135 unregister_netdevice_notifier(&mpls_dev_notifier);
1136 unregister_pernet_subsys(&mpls_net_ops);
1137 }
1138 module_exit(mpls_exit);
1139
1140 MODULE_DESCRIPTION("MultiProtocol Label Switching");
1141 MODULE_LICENSE("GPL v2");
1142 MODULE_ALIAS_NETPROTO(PF_MPLS);
Linux kernel - Deliverables
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