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Linux 3.8-rc7
[cris-mirror.git] / net / ipv4 / ip_gre.c
blobe81b1caf2ea2a0ceaa20ef8e1847ebd4f71cd98e
1 /*
2 * Linux NET3: GRE over IP protocol decoder.
3 *
4 * Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/capability.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/slab.h>
20 #include <asm/uaccess.h>
21 #include <linux/skbuff.h>
22 #include <linux/netdevice.h>
23 #include <linux/in.h>
24 #include <linux/tcp.h>
25 #include <linux/udp.h>
26 #include <linux/if_arp.h>
27 #include <linux/mroute.h>
28 #include <linux/init.h>
29 #include <linux/in6.h>
30 #include <linux/inetdevice.h>
31 #include <linux/igmp.h>
32 #include <linux/netfilter_ipv4.h>
33 #include <linux/etherdevice.h>
34 #include <linux/if_ether.h>
35
36 #include <net/sock.h>
37 #include <net/ip.h>
38 #include <net/icmp.h>
39 #include <net/protocol.h>
40 #include <net/ipip.h>
41 #include <net/arp.h>
42 #include <net/checksum.h>
43 #include <net/dsfield.h>
44 #include <net/inet_ecn.h>
45 #include <net/xfrm.h>
46 #include <net/net_namespace.h>
47 #include <net/netns/generic.h>
48 #include <net/rtnetlink.h>
49 #include <net/gre.h>
50
51 #if IS_ENABLED(CONFIG_IPV6)
52 #include <net/ipv6.h>
53 #include <net/ip6_fib.h>
54 #include <net/ip6_route.h>
55 #endif
56
57 /*
58 Problems & solutions
59 --------------------
60
61 1. The most important issue is detecting local dead loops.
62 They would cause complete host lockup in transmit, which
63 would be "resolved" by stack overflow or, if queueing is enabled,
64 with infinite looping in net_bh.
65
66 We cannot track such dead loops during route installation,
67 it is infeasible task. The most general solutions would be
68 to keep skb->encapsulation counter (sort of local ttl),
69 and silently drop packet when it expires. It is a good
70 solution, but it supposes maintaining new variable in ALL
71 skb, even if no tunneling is used.
72
73 Current solution: xmit_recursion breaks dead loops. This is a percpu
74 counter, since when we enter the first ndo_xmit(), cpu migration is
75 forbidden. We force an exit if this counter reaches RECURSION_LIMIT
76
77 2. Networking dead loops would not kill routers, but would really
78 kill network. IP hop limit plays role of "t->recursion" in this case,
79 if we copy it from packet being encapsulated to upper header.
80 It is very good solution, but it introduces two problems:
81
82 - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
83 do not work over tunnels.
84 - traceroute does not work. I planned to relay ICMP from tunnel,
85 so that this problem would be solved and traceroute output
86 would even more informative. This idea appeared to be wrong:
87 only Linux complies to rfc1812 now (yes, guys, Linux is the only
88 true router now :-)), all routers (at least, in neighbourhood of mine)
89 return only 8 bytes of payload. It is the end.
90
91 Hence, if we want that OSPF worked or traceroute said something reasonable,
92 we should search for another solution.
93
94 One of them is to parse packet trying to detect inner encapsulation
95 made by our node. It is difficult or even impossible, especially,
96 taking into account fragmentation. TO be short, ttl is not solution at all.
97
98 Current solution: The solution was UNEXPECTEDLY SIMPLE.
99 We force DF flag on tunnels with preconfigured hop limit,
100 that is ALL. :-) Well, it does not remove the problem completely,
101 but exponential growth of network traffic is changed to linear
102 (branches, that exceed pmtu are pruned) and tunnel mtu
103 rapidly degrades to value <68, where looping stops.
104 Yes, it is not good if there exists a router in the loop,
105 which does not force DF, even when encapsulating packets have DF set.
106 But it is not our problem! Nobody could accuse us, we made
107 all that we could make. Even if it is your gated who injected
108 fatal route to network, even if it were you who configured
109 fatal static route: you are innocent. :-)
110
111
112
113 3. Really, ipv4/ipip.c, ipv4/ip_gre.c and ipv6/sit.c contain
114 practically identical code. It would be good to glue them
115 together, but it is not very evident, how to make them modular.
116 sit is integral part of IPv6, ipip and gre are naturally modular.
117 We could extract common parts (hash table, ioctl etc)
118 to a separate module (ip_tunnel.c).
119
120 Alexey Kuznetsov.
121 */
122
123 static bool log_ecn_error = true;
124 module_param(log_ecn_error, bool, 0644);
125 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
126
127 static struct rtnl_link_ops ipgre_link_ops __read_mostly;
128 static int ipgre_tunnel_init(struct net_device *dev);
129 static void ipgre_tunnel_setup(struct net_device *dev);
130 static int ipgre_tunnel_bind_dev(struct net_device *dev);
131
132 /* Fallback tunnel: no source, no destination, no key, no options */
133
134 #define HASH_SIZE 16
135
136 static int ipgre_net_id __read_mostly;
137 struct ipgre_net {
138 struct ip_tunnel __rcu *tunnels[4][HASH_SIZE];
139
140 struct net_device *fb_tunnel_dev;
141 };
142
143 /* Tunnel hash table */
144
145 /*
146 4 hash tables:
147
148 3: (remote,local)
149 2: (remote,*)
150 1: (*,local)
151 0: (*,*)
152
153 We require exact key match i.e. if a key is present in packet
154 it will match only tunnel with the same key; if it is not present,
155 it will match only keyless tunnel.
156
157 All keysless packets, if not matched configured keyless tunnels
158 will match fallback tunnel.
159 */
160
161 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
162
163 #define tunnels_r_l tunnels[3]
164 #define tunnels_r tunnels[2]
165 #define tunnels_l tunnels[1]
166 #define tunnels_wc tunnels[0]
167
168 static struct rtnl_link_stats64 *ipgre_get_stats64(struct net_device *dev,
169 struct rtnl_link_stats64 *tot)
170 {
171 int i;
172
173 for_each_possible_cpu(i) {
174 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
175 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
176 unsigned int start;
177
178 do {
179 start = u64_stats_fetch_begin_bh(&tstats->syncp);
180 rx_packets = tstats->rx_packets;
181 tx_packets = tstats->tx_packets;
182 rx_bytes = tstats->rx_bytes;
183 tx_bytes = tstats->tx_bytes;
184 } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
185
186 tot->rx_packets += rx_packets;
187 tot->tx_packets += tx_packets;
188 tot->rx_bytes += rx_bytes;
189 tot->tx_bytes += tx_bytes;
190 }
191
192 tot->multicast = dev->stats.multicast;
193 tot->rx_crc_errors = dev->stats.rx_crc_errors;
194 tot->rx_fifo_errors = dev->stats.rx_fifo_errors;
195 tot->rx_length_errors = dev->stats.rx_length_errors;
196 tot->rx_frame_errors = dev->stats.rx_frame_errors;
197 tot->rx_errors = dev->stats.rx_errors;
198
199 tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
200 tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
201 tot->tx_dropped = dev->stats.tx_dropped;
202 tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
203 tot->tx_errors = dev->stats.tx_errors;
204
205 return tot;
206 }
207
208 /* Does key in tunnel parameters match packet */
209 static bool ipgre_key_match(const struct ip_tunnel_parm *p,
210 __be16 flags, __be32 key)
211 {
212 if (p->i_flags & GRE_KEY) {
213 if (flags & GRE_KEY)
214 return key == p->i_key;
215 else
216 return false; /* key expected, none present */
217 } else
218 return !(flags & GRE_KEY);
219 }
220
221 /* Given src, dst and key, find appropriate for input tunnel. */
222
223 static struct ip_tunnel *ipgre_tunnel_lookup(struct net_device *dev,
224 __be32 remote, __be32 local,
225 __be16 flags, __be32 key,
226 __be16 gre_proto)
227 {
228 struct net *net = dev_net(dev);
229 int link = dev->ifindex;
230 unsigned int h0 = HASH(remote);
231 unsigned int h1 = HASH(key);
232 struct ip_tunnel *t, *cand = NULL;
233 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
234 int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
235 ARPHRD_ETHER : ARPHRD_IPGRE;
236 int score, cand_score = 4;
237
238 for_each_ip_tunnel_rcu(t, ign->tunnels_r_l[h0 ^ h1]) {
239 if (local != t->parms.iph.saddr ||
240 remote != t->parms.iph.daddr ||
241 !(t->dev->flags & IFF_UP))
242 continue;
243
244 if (!ipgre_key_match(&t->parms, flags, key))
245 continue;
246
247 if (t->dev->type != ARPHRD_IPGRE &&
248 t->dev->type != dev_type)
249 continue;
250
251 score = 0;
252 if (t->parms.link != link)
253 score |= 1;
254 if (t->dev->type != dev_type)
255 score |= 2;
256 if (score == 0)
257 return t;
258
259 if (score < cand_score) {
260 cand = t;
261 cand_score = score;
262 }
263 }
264
265 for_each_ip_tunnel_rcu(t, ign->tunnels_r[h0 ^ h1]) {
266 if (remote != t->parms.iph.daddr ||
267 !(t->dev->flags & IFF_UP))
268 continue;
269
270 if (!ipgre_key_match(&t->parms, flags, key))
271 continue;
272
273 if (t->dev->type != ARPHRD_IPGRE &&
274 t->dev->type != dev_type)
275 continue;
276
277 score = 0;
278 if (t->parms.link != link)
279 score |= 1;
280 if (t->dev->type != dev_type)
281 score |= 2;
282 if (score == 0)
283 return t;
284
285 if (score < cand_score) {
286 cand = t;
287 cand_score = score;
288 }
289 }
290
291 for_each_ip_tunnel_rcu(t, ign->tunnels_l[h1]) {
292 if ((local != t->parms.iph.saddr &&
293 (local != t->parms.iph.daddr ||
294 !ipv4_is_multicast(local))) ||
295 !(t->dev->flags & IFF_UP))
296 continue;
297
298 if (!ipgre_key_match(&t->parms, flags, key))
299 continue;
300
301 if (t->dev->type != ARPHRD_IPGRE &&
302 t->dev->type != dev_type)
303 continue;
304
305 score = 0;
306 if (t->parms.link != link)
307 score |= 1;
308 if (t->dev->type != dev_type)
309 score |= 2;
310 if (score == 0)
311 return t;
312
313 if (score < cand_score) {
314 cand = t;
315 cand_score = score;
316 }
317 }
318
319 for_each_ip_tunnel_rcu(t, ign->tunnels_wc[h1]) {
320 if (t->parms.i_key != key ||
321 !(t->dev->flags & IFF_UP))
322 continue;
323
324 if (t->dev->type != ARPHRD_IPGRE &&
325 t->dev->type != dev_type)
326 continue;
327
328 score = 0;
329 if (t->parms.link != link)
330 score |= 1;
331 if (t->dev->type != dev_type)
332 score |= 2;
333 if (score == 0)
334 return t;
335
336 if (score < cand_score) {
337 cand = t;
338 cand_score = score;
339 }
340 }
341
342 if (cand != NULL)
343 return cand;
344
345 dev = ign->fb_tunnel_dev;
346 if (dev->flags & IFF_UP)
347 return netdev_priv(dev);
348
349 return NULL;
350 }
351
352 static struct ip_tunnel __rcu **__ipgre_bucket(struct ipgre_net *ign,
353 struct ip_tunnel_parm *parms)
354 {
355 __be32 remote = parms->iph.daddr;
356 __be32 local = parms->iph.saddr;
357 __be32 key = parms->i_key;
358 unsigned int h = HASH(key);
359 int prio = 0;
360
361 if (local)
362 prio |= 1;
363 if (remote && !ipv4_is_multicast(remote)) {
364 prio |= 2;
365 h ^= HASH(remote);
366 }
367
368 return &ign->tunnels[prio][h];
369 }
370
371 static inline struct ip_tunnel __rcu **ipgre_bucket(struct ipgre_net *ign,
372 struct ip_tunnel *t)
373 {
374 return __ipgre_bucket(ign, &t->parms);
375 }
376
377 static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t)
378 {
379 struct ip_tunnel __rcu **tp = ipgre_bucket(ign, t);
380
381 rcu_assign_pointer(t->next, rtnl_dereference(*tp));
382 rcu_assign_pointer(*tp, t);
383 }
384
385 static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t)
386 {
387 struct ip_tunnel __rcu **tp;
388 struct ip_tunnel *iter;
389
390 for (tp = ipgre_bucket(ign, t);
391 (iter = rtnl_dereference(*tp)) != NULL;
392 tp = &iter->next) {
393 if (t == iter) {
394 rcu_assign_pointer(*tp, t->next);
395 break;
396 }
397 }
398 }
399
400 static struct ip_tunnel *ipgre_tunnel_find(struct net *net,
401 struct ip_tunnel_parm *parms,
402 int type)
403 {
404 __be32 remote = parms->iph.daddr;
405 __be32 local = parms->iph.saddr;
406 __be32 key = parms->i_key;
407 int link = parms->link;
408 struct ip_tunnel *t;
409 struct ip_tunnel __rcu **tp;
410 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
411
412 for (tp = __ipgre_bucket(ign, parms);
413 (t = rtnl_dereference(*tp)) != NULL;
414 tp = &t->next)
415 if (local == t->parms.iph.saddr &&
416 remote == t->parms.iph.daddr &&
417 key == t->parms.i_key &&
418 link == t->parms.link &&
419 type == t->dev->type)
420 break;
421
422 return t;
423 }
424
425 static struct ip_tunnel *ipgre_tunnel_locate(struct net *net,
426 struct ip_tunnel_parm *parms, int create)
427 {
428 struct ip_tunnel *t, *nt;
429 struct net_device *dev;
430 char name[IFNAMSIZ];
431 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
432
433 t = ipgre_tunnel_find(net, parms, ARPHRD_IPGRE);
434 if (t || !create)
435 return t;
436
437 if (parms->name[0])
438 strlcpy(name, parms->name, IFNAMSIZ);
439 else
440 strcpy(name, "gre%d");
441
442 dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup);
443 if (!dev)
444 return NULL;
445
446 dev_net_set(dev, net);
447
448 nt = netdev_priv(dev);
449 nt->parms = *parms;
450 dev->rtnl_link_ops = &ipgre_link_ops;
451
452 dev->mtu = ipgre_tunnel_bind_dev(dev);
453
454 if (register_netdevice(dev) < 0)
455 goto failed_free;
456
457 /* Can use a lockless transmit, unless we generate output sequences */
458 if (!(nt->parms.o_flags & GRE_SEQ))
459 dev->features |= NETIF_F_LLTX;
460
461 dev_hold(dev);
462 ipgre_tunnel_link(ign, nt);
463 return nt;
464
465 failed_free:
466 free_netdev(dev);
467 return NULL;
468 }
469
470 static void ipgre_tunnel_uninit(struct net_device *dev)
471 {
472 struct net *net = dev_net(dev);
473 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
474
475 ipgre_tunnel_unlink(ign, netdev_priv(dev));
476 dev_put(dev);
477 }
478
479
480 static void ipgre_err(struct sk_buff *skb, u32 info)
481 {
482
483 /* All the routers (except for Linux) return only
484 8 bytes of packet payload. It means, that precise relaying of
485 ICMP in the real Internet is absolutely infeasible.
486
487 Moreover, Cisco "wise men" put GRE key to the third word
488 in GRE header. It makes impossible maintaining even soft state for keyed
489 GRE tunnels with enabled checksum. Tell them "thank you".
490
491 Well, I wonder, rfc1812 was written by Cisco employee,
492 what the hell these idiots break standards established
493 by themselves???
494 */
495
496 const struct iphdr *iph = (const struct iphdr *)skb->data;
497 __be16 *p = (__be16 *)(skb->data+(iph->ihl<<2));
498 int grehlen = (iph->ihl<<2) + 4;
499 const int type = icmp_hdr(skb)->type;
500 const int code = icmp_hdr(skb)->code;
501 struct ip_tunnel *t;
502 __be16 flags;
503 __be32 key = 0;
504
505 flags = p[0];
506 if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
507 if (flags&(GRE_VERSION|GRE_ROUTING))
508 return;
509 if (flags&GRE_KEY) {
510 grehlen += 4;
511 if (flags&GRE_CSUM)
512 grehlen += 4;
513 }
514 }
515
516 /* If only 8 bytes returned, keyed message will be dropped here */
517 if (skb_headlen(skb) < grehlen)
518 return;
519
520 if (flags & GRE_KEY)
521 key = *(((__be32 *)p) + (grehlen / 4) - 1);
522
523 switch (type) {
524 default:
525 case ICMP_PARAMETERPROB:
526 return;
527
528 case ICMP_DEST_UNREACH:
529 switch (code) {
530 case ICMP_SR_FAILED:
531 case ICMP_PORT_UNREACH:
532 /* Impossible event. */
533 return;
534 default:
535 /* All others are translated to HOST_UNREACH.
536 rfc2003 contains "deep thoughts" about NET_UNREACH,
537 I believe they are just ether pollution. --ANK
538 */
539 break;
540 }
541 break;
542 case ICMP_TIME_EXCEEDED:
543 if (code != ICMP_EXC_TTL)
544 return;
545 break;
546
547 case ICMP_REDIRECT:
548 break;
549 }
550
551 t = ipgre_tunnel_lookup(skb->dev, iph->daddr, iph->saddr,
552 flags, key, p[1]);
553
554 if (t == NULL)
555 return;
556
557 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
558 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
559 t->parms.link, 0, IPPROTO_GRE, 0);
560 return;
561 }
562 if (type == ICMP_REDIRECT) {
563 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
564 IPPROTO_GRE, 0);
565 return;
566 }
567 if (t->parms.iph.daddr == 0 ||
568 ipv4_is_multicast(t->parms.iph.daddr))
569 return;
570
571 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
572 return;
573
574 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
575 t->err_count++;
576 else
577 t->err_count = 1;
578 t->err_time = jiffies;
579 }
580
581 static inline u8
582 ipgre_ecn_encapsulate(u8 tos, const struct iphdr *old_iph, struct sk_buff *skb)
583 {
584 u8 inner = 0;
585 if (skb->protocol == htons(ETH_P_IP))
586 inner = old_iph->tos;
587 else if (skb->protocol == htons(ETH_P_IPV6))
588 inner = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
589 return INET_ECN_encapsulate(tos, inner);
590 }
591
592 static int ipgre_rcv(struct sk_buff *skb)
593 {
594 const struct iphdr *iph;
595 u8 *h;
596 __be16 flags;
597 __sum16 csum = 0;
598 __be32 key = 0;
599 u32 seqno = 0;
600 struct ip_tunnel *tunnel;
601 int offset = 4;
602 __be16 gre_proto;
603 int err;
604
605 if (!pskb_may_pull(skb, 16))
606 goto drop;
607
608 iph = ip_hdr(skb);
609 h = skb->data;
610 flags = *(__be16 *)h;
611
612 if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
613 /* - Version must be 0.
614 - We do not support routing headers.
615 */
616 if (flags&(GRE_VERSION|GRE_ROUTING))
617 goto drop;
618
619 if (flags&GRE_CSUM) {
620 switch (skb->ip_summed) {
621 case CHECKSUM_COMPLETE:
622 csum = csum_fold(skb->csum);
623 if (!csum)
624 break;
625 /* fall through */
626 case CHECKSUM_NONE:
627 skb->csum = 0;
628 csum = __skb_checksum_complete(skb);
629 skb->ip_summed = CHECKSUM_COMPLETE;
630 }
631 offset += 4;
632 }
633 if (flags&GRE_KEY) {
634 key = *(__be32 *)(h + offset);
635 offset += 4;
636 }
637 if (flags&GRE_SEQ) {
638 seqno = ntohl(*(__be32 *)(h + offset));
639 offset += 4;
640 }
641 }
642
643 gre_proto = *(__be16 *)(h + 2);
644
645 tunnel = ipgre_tunnel_lookup(skb->dev,
646 iph->saddr, iph->daddr, flags, key,
647 gre_proto);
648 if (tunnel) {
649 struct pcpu_tstats *tstats;
650
651 secpath_reset(skb);
652
653 skb->protocol = gre_proto;
654 /* WCCP version 1 and 2 protocol decoding.
655 * - Change protocol to IP
656 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
657 */
658 if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
659 skb->protocol = htons(ETH_P_IP);
660 if ((*(h + offset) & 0xF0) != 0x40)
661 offset += 4;
662 }
663
664 skb->mac_header = skb->network_header;
665 __pskb_pull(skb, offset);
666 skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
667 skb->pkt_type = PACKET_HOST;
668 #ifdef CONFIG_NET_IPGRE_BROADCAST
669 if (ipv4_is_multicast(iph->daddr)) {
670 /* Looped back packet, drop it! */
671 if (rt_is_output_route(skb_rtable(skb)))
672 goto drop;
673 tunnel->dev->stats.multicast++;
674 skb->pkt_type = PACKET_BROADCAST;
675 }
676 #endif
677
678 if (((flags&GRE_CSUM) && csum) ||
679 (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
680 tunnel->dev->stats.rx_crc_errors++;
681 tunnel->dev->stats.rx_errors++;
682 goto drop;
683 }
684 if (tunnel->parms.i_flags&GRE_SEQ) {
685 if (!(flags&GRE_SEQ) ||
686 (tunnel->i_seqno && (s32)(seqno - tunnel->i_seqno) < 0)) {
687 tunnel->dev->stats.rx_fifo_errors++;
688 tunnel->dev->stats.rx_errors++;
689 goto drop;
690 }
691 tunnel->i_seqno = seqno + 1;
692 }
693
694 /* Warning: All skb pointers will be invalidated! */
695 if (tunnel->dev->type == ARPHRD_ETHER) {
696 if (!pskb_may_pull(skb, ETH_HLEN)) {
697 tunnel->dev->stats.rx_length_errors++;
698 tunnel->dev->stats.rx_errors++;
699 goto drop;
700 }
701
702 iph = ip_hdr(skb);
703 skb->protocol = eth_type_trans(skb, tunnel->dev);
704 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
705 }
706
707 __skb_tunnel_rx(skb, tunnel->dev);
708
709 skb_reset_network_header(skb);
710 err = IP_ECN_decapsulate(iph, skb);
711 if (unlikely(err)) {
712 if (log_ecn_error)
713 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
714 &iph->saddr, iph->tos);
715 if (err > 1) {
716 ++tunnel->dev->stats.rx_frame_errors;
717 ++tunnel->dev->stats.rx_errors;
718 goto drop;
719 }
720 }
721
722 tstats = this_cpu_ptr(tunnel->dev->tstats);
723 u64_stats_update_begin(&tstats->syncp);
724 tstats->rx_packets++;
725 tstats->rx_bytes += skb->len;
726 u64_stats_update_end(&tstats->syncp);
727
728 gro_cells_receive(&tunnel->gro_cells, skb);
729 return 0;
730 }
731 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
732
733 drop:
734 kfree_skb(skb);
735 return 0;
736 }
737
738 static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
739 {
740 struct ip_tunnel *tunnel = netdev_priv(dev);
741 const struct iphdr *old_iph = ip_hdr(skb);
742 const struct iphdr *tiph;
743 struct flowi4 fl4;
744 u8 tos;
745 __be16 df;
746 struct rtable *rt; /* Route to the other host */
747 struct net_device *tdev; /* Device to other host */
748 struct iphdr *iph; /* Our new IP header */
749 unsigned int max_headroom; /* The extra header space needed */
750 int gre_hlen;
751 __be32 dst;
752 int mtu;
753 u8 ttl;
754
755 if (skb->ip_summed == CHECKSUM_PARTIAL &&
756 skb_checksum_help(skb))
757 goto tx_error;
758
759 if (dev->type == ARPHRD_ETHER)
760 IPCB(skb)->flags = 0;
761
762 if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
763 gre_hlen = 0;
764 if (skb->protocol == htons(ETH_P_IP))
765 tiph = (const struct iphdr *)skb->data;
766 else
767 tiph = &tunnel->parms.iph;
768 } else {
769 gre_hlen = tunnel->hlen;
770 tiph = &tunnel->parms.iph;
771 }
772
773 if ((dst = tiph->daddr) == 0) {
774 /* NBMA tunnel */
775
776 if (skb_dst(skb) == NULL) {
777 dev->stats.tx_fifo_errors++;
778 goto tx_error;
779 }
780
781 if (skb->protocol == htons(ETH_P_IP)) {
782 rt = skb_rtable(skb);
783 dst = rt_nexthop(rt, old_iph->daddr);
784 }
785 #if IS_ENABLED(CONFIG_IPV6)
786 else if (skb->protocol == htons(ETH_P_IPV6)) {
787 const struct in6_addr *addr6;
788 struct neighbour *neigh;
789 bool do_tx_error_icmp;
790 int addr_type;
791
792 neigh = dst_neigh_lookup(skb_dst(skb), &ipv6_hdr(skb)->daddr);
793 if (neigh == NULL)
794 goto tx_error;
795
796 addr6 = (const struct in6_addr *)&neigh->primary_key;
797 addr_type = ipv6_addr_type(addr6);
798
799 if (addr_type == IPV6_ADDR_ANY) {
800 addr6 = &ipv6_hdr(skb)->daddr;
801 addr_type = ipv6_addr_type(addr6);
802 }
803
804 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
805 do_tx_error_icmp = true;
806 else {
807 do_tx_error_icmp = false;
808 dst = addr6->s6_addr32[3];
809 }
810 neigh_release(neigh);
811 if (do_tx_error_icmp)
812 goto tx_error_icmp;
813 }
814 #endif
815 else
816 goto tx_error;
817 }
818
819 ttl = tiph->ttl;
820 tos = tiph->tos;
821 if (tos == 1) {
822 tos = 0;
823 if (skb->protocol == htons(ETH_P_IP))
824 tos = old_iph->tos;
825 else if (skb->protocol == htons(ETH_P_IPV6))
826 tos = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
827 }
828
829 rt = ip_route_output_gre(dev_net(dev), &fl4, dst, tiph->saddr,
830 tunnel->parms.o_key, RT_TOS(tos),
831 tunnel->parms.link);
832 if (IS_ERR(rt)) {
833 dev->stats.tx_carrier_errors++;
834 goto tx_error;
835 }
836 tdev = rt->dst.dev;
837
838 if (tdev == dev) {
839 ip_rt_put(rt);
840 dev->stats.collisions++;
841 goto tx_error;
842 }
843
844 df = tiph->frag_off;
845 if (df)
846 mtu = dst_mtu(&rt->dst) - dev->hard_header_len - tunnel->hlen;
847 else
848 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
849
850 if (skb_dst(skb))
851 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
852
853 if (skb->protocol == htons(ETH_P_IP)) {
854 df |= (old_iph->frag_off&htons(IP_DF));
855
856 if ((old_iph->frag_off&htons(IP_DF)) &&
857 mtu < ntohs(old_iph->tot_len)) {
858 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
859 ip_rt_put(rt);
860 goto tx_error;
861 }
862 }
863 #if IS_ENABLED(CONFIG_IPV6)
864 else if (skb->protocol == htons(ETH_P_IPV6)) {
865 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
866
867 if (rt6 && mtu < dst_mtu(skb_dst(skb)) && mtu >= IPV6_MIN_MTU) {
868 if ((tunnel->parms.iph.daddr &&
869 !ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
870 rt6->rt6i_dst.plen == 128) {
871 rt6->rt6i_flags |= RTF_MODIFIED;
872 dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
873 }
874 }
875
876 if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) {
877 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
878 ip_rt_put(rt);
879 goto tx_error;
880 }
881 }
882 #endif
883
884 if (tunnel->err_count > 0) {
885 if (time_before(jiffies,
886 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
887 tunnel->err_count--;
888
889 dst_link_failure(skb);
890 } else
891 tunnel->err_count = 0;
892 }
893
894 max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen + rt->dst.header_len;
895
896 if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
897 (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
898 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
899 if (max_headroom > dev->needed_headroom)
900 dev->needed_headroom = max_headroom;
901 if (!new_skb) {
902 ip_rt_put(rt);
903 dev->stats.tx_dropped++;
904 dev_kfree_skb(skb);
905 return NETDEV_TX_OK;
906 }
907 if (skb->sk)
908 skb_set_owner_w(new_skb, skb->sk);
909 dev_kfree_skb(skb);
910 skb = new_skb;
911 old_iph = ip_hdr(skb);
912 /* Warning : tiph value might point to freed memory */
913 }
914
915 skb_push(skb, gre_hlen);
916 skb_reset_network_header(skb);
917 skb_set_transport_header(skb, sizeof(*iph));
918 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
919 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
920 IPSKB_REROUTED);
921 skb_dst_drop(skb);
922 skb_dst_set(skb, &rt->dst);
923
924 /*
925 * Push down and install the IPIP header.
926 */
927
928 iph = ip_hdr(skb);
929 iph->version = 4;
930 iph->ihl = sizeof(struct iphdr) >> 2;
931 iph->frag_off = df;
932 iph->protocol = IPPROTO_GRE;
933 iph->tos = ipgre_ecn_encapsulate(tos, old_iph, skb);
934 iph->daddr = fl4.daddr;
935 iph->saddr = fl4.saddr;
936 iph->ttl = ttl;
937
938 if (ttl == 0) {
939 if (skb->protocol == htons(ETH_P_IP))
940 iph->ttl = old_iph->ttl;
941 #if IS_ENABLED(CONFIG_IPV6)
942 else if (skb->protocol == htons(ETH_P_IPV6))
943 iph->ttl = ((const struct ipv6hdr *)old_iph)->hop_limit;
944 #endif
945 else
946 iph->ttl = ip4_dst_hoplimit(&rt->dst);
947 }
948
949 ((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags;
950 ((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ?
951 htons(ETH_P_TEB) : skb->protocol;
952
953 if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
954 __be32 *ptr = (__be32 *)(((u8 *)iph) + tunnel->hlen - 4);
955
956 if (tunnel->parms.o_flags&GRE_SEQ) {
957 ++tunnel->o_seqno;
958 *ptr = htonl(tunnel->o_seqno);
959 ptr--;
960 }
961 if (tunnel->parms.o_flags&GRE_KEY) {
962 *ptr = tunnel->parms.o_key;
963 ptr--;
964 }
965 if (tunnel->parms.o_flags&GRE_CSUM) {
966 int offset = skb_transport_offset(skb);
967
968 *ptr = 0;
969 *(__sum16 *)ptr = csum_fold(skb_checksum(skb, offset,
970 skb->len - offset,
971 0));
972 }
973 }
974
975 iptunnel_xmit(skb, dev);
976 return NETDEV_TX_OK;
977
978 #if IS_ENABLED(CONFIG_IPV6)
979 tx_error_icmp:
980 dst_link_failure(skb);
981 #endif
982 tx_error:
983 dev->stats.tx_errors++;
984 dev_kfree_skb(skb);
985 return NETDEV_TX_OK;
986 }
987
988 static int ipgre_tunnel_bind_dev(struct net_device *dev)
989 {
990 struct net_device *tdev = NULL;
991 struct ip_tunnel *tunnel;
992 const struct iphdr *iph;
993 int hlen = LL_MAX_HEADER;
994 int mtu = ETH_DATA_LEN;
995 int addend = sizeof(struct iphdr) + 4;
996
997 tunnel = netdev_priv(dev);
998 iph = &tunnel->parms.iph;
999
1000 /* Guess output device to choose reasonable mtu and needed_headroom */
1001
1002 if (iph->daddr) {
1003 struct flowi4 fl4;
1004 struct rtable *rt;
1005
1006 rt = ip_route_output_gre(dev_net(dev), &fl4,
1007 iph->daddr, iph->saddr,
1008 tunnel->parms.o_key,
1009 RT_TOS(iph->tos),
1010 tunnel->parms.link);
1011 if (!IS_ERR(rt)) {
1012 tdev = rt->dst.dev;
1013 ip_rt_put(rt);
1014 }
1015
1016 if (dev->type != ARPHRD_ETHER)
1017 dev->flags |= IFF_POINTOPOINT;
1018 }
1019
1020 if (!tdev && tunnel->parms.link)
1021 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
1022
1023 if (tdev) {
1024 hlen = tdev->hard_header_len + tdev->needed_headroom;
1025 mtu = tdev->mtu;
1026 }
1027 dev->iflink = tunnel->parms.link;
1028
1029 /* Precalculate GRE options length */
1030 if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) {
1031 if (tunnel->parms.o_flags&GRE_CSUM)
1032 addend += 4;
1033 if (tunnel->parms.o_flags&GRE_KEY)
1034 addend += 4;
1035 if (tunnel->parms.o_flags&GRE_SEQ)
1036 addend += 4;
1037 }
1038 dev->needed_headroom = addend + hlen;
1039 mtu -= dev->hard_header_len + addend;
1040
1041 if (mtu < 68)
1042 mtu = 68;
1043
1044 tunnel->hlen = addend;
1045
1046 return mtu;
1047 }
1048
1049 static int
1050 ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
1051 {
1052 int err = 0;
1053 struct ip_tunnel_parm p;
1054 struct ip_tunnel *t;
1055 struct net *net = dev_net(dev);
1056 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1057
1058 switch (cmd) {
1059 case SIOCGETTUNNEL:
1060 t = NULL;
1061 if (dev == ign->fb_tunnel_dev) {
1062 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1063 err = -EFAULT;
1064 break;
1065 }
1066 t = ipgre_tunnel_locate(net, &p, 0);
1067 }
1068 if (t == NULL)
1069 t = netdev_priv(dev);
1070 memcpy(&p, &t->parms, sizeof(p));
1071 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1072 err = -EFAULT;
1073 break;
1074
1075 case SIOCADDTUNNEL:
1076 case SIOCCHGTUNNEL:
1077 err = -EPERM;
1078 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1079 goto done;
1080
1081 err = -EFAULT;
1082 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1083 goto done;
1084
1085 err = -EINVAL;
1086 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
1087 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
1088 ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
1089 goto done;
1090 if (p.iph.ttl)
1091 p.iph.frag_off |= htons(IP_DF);
1092
1093 if (!(p.i_flags&GRE_KEY))
1094 p.i_key = 0;
1095 if (!(p.o_flags&GRE_KEY))
1096 p.o_key = 0;
1097
1098 t = ipgre_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1099
1100 if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1101 if (t != NULL) {
1102 if (t->dev != dev) {
1103 err = -EEXIST;
1104 break;
1105 }
1106 } else {
1107 unsigned int nflags = 0;
1108
1109 t = netdev_priv(dev);
1110
1111 if (ipv4_is_multicast(p.iph.daddr))
1112 nflags = IFF_BROADCAST;
1113 else if (p.iph.daddr)
1114 nflags = IFF_POINTOPOINT;
1115
1116 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
1117 err = -EINVAL;
1118 break;
1119 }
1120 ipgre_tunnel_unlink(ign, t);
1121 synchronize_net();
1122 t->parms.iph.saddr = p.iph.saddr;
1123 t->parms.iph.daddr = p.iph.daddr;
1124 t->parms.i_key = p.i_key;
1125 t->parms.o_key = p.o_key;
1126 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1127 memcpy(dev->broadcast, &p.iph.daddr, 4);
1128 ipgre_tunnel_link(ign, t);
1129 netdev_state_change(dev);
1130 }
1131 }
1132
1133 if (t) {
1134 err = 0;
1135 if (cmd == SIOCCHGTUNNEL) {
1136 t->parms.iph.ttl = p.iph.ttl;
1137 t->parms.iph.tos = p.iph.tos;
1138 t->parms.iph.frag_off = p.iph.frag_off;
1139 if (t->parms.link != p.link) {
1140 t->parms.link = p.link;
1141 dev->mtu = ipgre_tunnel_bind_dev(dev);
1142 netdev_state_change(dev);
1143 }
1144 }
1145 if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1146 err = -EFAULT;
1147 } else
1148 err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1149 break;
1150
1151 case SIOCDELTUNNEL:
1152 err = -EPERM;
1153 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1154 goto done;
1155
1156 if (dev == ign->fb_tunnel_dev) {
1157 err = -EFAULT;
1158 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1159 goto done;
1160 err = -ENOENT;
1161 if ((t = ipgre_tunnel_locate(net, &p, 0)) == NULL)
1162 goto done;
1163 err = -EPERM;
1164 if (t == netdev_priv(ign->fb_tunnel_dev))
1165 goto done;
1166 dev = t->dev;
1167 }
1168 unregister_netdevice(dev);
1169 err = 0;
1170 break;
1171
1172 default:
1173 err = -EINVAL;
1174 }
1175
1176 done:
1177 return err;
1178 }
1179
1180 static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1181 {
1182 struct ip_tunnel *tunnel = netdev_priv(dev);
1183 if (new_mtu < 68 ||
1184 new_mtu > 0xFFF8 - dev->hard_header_len - tunnel->hlen)
1185 return -EINVAL;
1186 dev->mtu = new_mtu;
1187 return 0;
1188 }
1189
1190 /* Nice toy. Unfortunately, useless in real life :-)
1191 It allows to construct virtual multiprotocol broadcast "LAN"
1192 over the Internet, provided multicast routing is tuned.
1193
1194
1195 I have no idea was this bicycle invented before me,
1196 so that I had to set ARPHRD_IPGRE to a random value.
1197 I have an impression, that Cisco could make something similar,
1198 but this feature is apparently missing in IOS<=11.2(8).
1199
1200 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
1201 with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
1202
1203 ping -t 255 224.66.66.66
1204
1205 If nobody answers, mbone does not work.
1206
1207 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
1208 ip addr add 10.66.66.<somewhat>/24 dev Universe
1209 ifconfig Universe up
1210 ifconfig Universe add fe80::<Your_real_addr>/10
1211 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
1212 ftp 10.66.66.66
1213 ...
1214 ftp fec0:6666:6666::193.233.7.65
1215 ...
1216
1217 */
1218
1219 static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
1220 unsigned short type,
1221 const void *daddr, const void *saddr, unsigned int len)
1222 {
1223 struct ip_tunnel *t = netdev_priv(dev);
1224 struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
1225 __be16 *p = (__be16 *)(iph+1);
1226
1227 memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
1228 p[0] = t->parms.o_flags;
1229 p[1] = htons(type);
1230
1231 /*
1232 * Set the source hardware address.
1233 */
1234
1235 if (saddr)
1236 memcpy(&iph->saddr, saddr, 4);
1237 if (daddr)
1238 memcpy(&iph->daddr, daddr, 4);
1239 if (iph->daddr)
1240 return t->hlen;
1241
1242 return -t->hlen;
1243 }
1244
1245 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
1246 {
1247 const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
1248 memcpy(haddr, &iph->saddr, 4);
1249 return 4;
1250 }
1251
1252 static const struct header_ops ipgre_header_ops = {
1253 .create = ipgre_header,
1254 .parse = ipgre_header_parse,
1255 };
1256
1257 #ifdef CONFIG_NET_IPGRE_BROADCAST
1258 static int ipgre_open(struct net_device *dev)
1259 {
1260 struct ip_tunnel *t = netdev_priv(dev);
1261
1262 if (ipv4_is_multicast(t->parms.iph.daddr)) {
1263 struct flowi4 fl4;
1264 struct rtable *rt;
1265
1266 rt = ip_route_output_gre(dev_net(dev), &fl4,
1267 t->parms.iph.daddr,
1268 t->parms.iph.saddr,
1269 t->parms.o_key,
1270 RT_TOS(t->parms.iph.tos),
1271 t->parms.link);
1272 if (IS_ERR(rt))
1273 return -EADDRNOTAVAIL;
1274 dev = rt->dst.dev;
1275 ip_rt_put(rt);
1276 if (__in_dev_get_rtnl(dev) == NULL)
1277 return -EADDRNOTAVAIL;
1278 t->mlink = dev->ifindex;
1279 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
1280 }
1281 return 0;
1282 }
1283
1284 static int ipgre_close(struct net_device *dev)
1285 {
1286 struct ip_tunnel *t = netdev_priv(dev);
1287
1288 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
1289 struct in_device *in_dev;
1290 in_dev = inetdev_by_index(dev_net(dev), t->mlink);
1291 if (in_dev)
1292 ip_mc_dec_group(in_dev, t->parms.iph.daddr);
1293 }
1294 return 0;
1295 }
1296
1297 #endif
1298
1299 static const struct net_device_ops ipgre_netdev_ops = {
1300 .ndo_init = ipgre_tunnel_init,
1301 .ndo_uninit = ipgre_tunnel_uninit,
1302 #ifdef CONFIG_NET_IPGRE_BROADCAST
1303 .ndo_open = ipgre_open,
1304 .ndo_stop = ipgre_close,
1305 #endif
1306 .ndo_start_xmit = ipgre_tunnel_xmit,
1307 .ndo_do_ioctl = ipgre_tunnel_ioctl,
1308 .ndo_change_mtu = ipgre_tunnel_change_mtu,
1309 .ndo_get_stats64 = ipgre_get_stats64,
1310 };
1311
1312 static void ipgre_dev_free(struct net_device *dev)
1313 {
1314 struct ip_tunnel *tunnel = netdev_priv(dev);
1315
1316 gro_cells_destroy(&tunnel->gro_cells);
1317 free_percpu(dev->tstats);
1318 free_netdev(dev);
1319 }
1320
1321 #define GRE_FEATURES (NETIF_F_SG | \
1322 NETIF_F_FRAGLIST | \
1323 NETIF_F_HIGHDMA | \
1324 NETIF_F_HW_CSUM)
1325
1326 static void ipgre_tunnel_setup(struct net_device *dev)
1327 {
1328 dev->netdev_ops = &ipgre_netdev_ops;
1329 dev->destructor = ipgre_dev_free;
1330
1331 dev->type = ARPHRD_IPGRE;
1332 dev->needed_headroom = LL_MAX_HEADER + sizeof(struct iphdr) + 4;
1333 dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr) - 4;
1334 dev->flags = IFF_NOARP;
1335 dev->iflink = 0;
1336 dev->addr_len = 4;
1337 dev->features |= NETIF_F_NETNS_LOCAL;
1338 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1339
1340 dev->features |= GRE_FEATURES;
1341 dev->hw_features |= GRE_FEATURES;
1342 }
1343
1344 static int ipgre_tunnel_init(struct net_device *dev)
1345 {
1346 struct ip_tunnel *tunnel;
1347 struct iphdr *iph;
1348 int err;
1349
1350 tunnel = netdev_priv(dev);
1351 iph = &tunnel->parms.iph;
1352
1353 tunnel->dev = dev;
1354 strcpy(tunnel->parms.name, dev->name);
1355
1356 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1357 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1358
1359 if (iph->daddr) {
1360 #ifdef CONFIG_NET_IPGRE_BROADCAST
1361 if (ipv4_is_multicast(iph->daddr)) {
1362 if (!iph->saddr)
1363 return -EINVAL;
1364 dev->flags = IFF_BROADCAST;
1365 dev->header_ops = &ipgre_header_ops;
1366 }
1367 #endif
1368 } else
1369 dev->header_ops = &ipgre_header_ops;
1370
1371 dev->tstats = alloc_percpu(struct pcpu_tstats);
1372 if (!dev->tstats)
1373 return -ENOMEM;
1374
1375 err = gro_cells_init(&tunnel->gro_cells, dev);
1376 if (err) {
1377 free_percpu(dev->tstats);
1378 return err;
1379 }
1380
1381 return 0;
1382 }
1383
1384 static void ipgre_fb_tunnel_init(struct net_device *dev)
1385 {
1386 struct ip_tunnel *tunnel = netdev_priv(dev);
1387 struct iphdr *iph = &tunnel->parms.iph;
1388
1389 tunnel->dev = dev;
1390 strcpy(tunnel->parms.name, dev->name);
1391
1392 iph->version = 4;
1393 iph->protocol = IPPROTO_GRE;
1394 iph->ihl = 5;
1395 tunnel->hlen = sizeof(struct iphdr) + 4;
1396
1397 dev_hold(dev);
1398 }
1399
1400
1401 static const struct gre_protocol ipgre_protocol = {
1402 .handler = ipgre_rcv,
1403 .err_handler = ipgre_err,
1404 };
1405
1406 static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head)
1407 {
1408 int prio;
1409
1410 for (prio = 0; prio < 4; prio++) {
1411 int h;
1412 for (h = 0; h < HASH_SIZE; h++) {
1413 struct ip_tunnel *t;
1414
1415 t = rtnl_dereference(ign->tunnels[prio][h]);
1416
1417 while (t != NULL) {
1418 unregister_netdevice_queue(t->dev, head);
1419 t = rtnl_dereference(t->next);
1420 }
1421 }
1422 }
1423 }
1424
1425 static int __net_init ipgre_init_net(struct net *net)
1426 {
1427 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1428 int err;
1429
1430 ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0",
1431 ipgre_tunnel_setup);
1432 if (!ign->fb_tunnel_dev) {
1433 err = -ENOMEM;
1434 goto err_alloc_dev;
1435 }
1436 dev_net_set(ign->fb_tunnel_dev, net);
1437
1438 ipgre_fb_tunnel_init(ign->fb_tunnel_dev);
1439 ign->fb_tunnel_dev->rtnl_link_ops = &ipgre_link_ops;
1440
1441 if ((err = register_netdev(ign->fb_tunnel_dev)))
1442 goto err_reg_dev;
1443
1444 rcu_assign_pointer(ign->tunnels_wc[0],
1445 netdev_priv(ign->fb_tunnel_dev));
1446 return 0;
1447
1448 err_reg_dev:
1449 ipgre_dev_free(ign->fb_tunnel_dev);
1450 err_alloc_dev:
1451 return err;
1452 }
1453
1454 static void __net_exit ipgre_exit_net(struct net *net)
1455 {
1456 struct ipgre_net *ign;
1457 LIST_HEAD(list);
1458
1459 ign = net_generic(net, ipgre_net_id);
1460 rtnl_lock();
1461 ipgre_destroy_tunnels(ign, &list);
1462 unregister_netdevice_many(&list);
1463 rtnl_unlock();
1464 }
1465
1466 static struct pernet_operations ipgre_net_ops = {
1467 .init = ipgre_init_net,
1468 .exit = ipgre_exit_net,
1469 .id = &ipgre_net_id,
1470 .size = sizeof(struct ipgre_net),
1471 };
1472
1473 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
1474 {
1475 __be16 flags;
1476
1477 if (!data)
1478 return 0;
1479
1480 flags = 0;
1481 if (data[IFLA_GRE_IFLAGS])
1482 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1483 if (data[IFLA_GRE_OFLAGS])
1484 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1485 if (flags & (GRE_VERSION|GRE_ROUTING))
1486 return -EINVAL;
1487
1488 return 0;
1489 }
1490
1491 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
1492 {
1493 __be32 daddr;
1494
1495 if (tb[IFLA_ADDRESS]) {
1496 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1497 return -EINVAL;
1498 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1499 return -EADDRNOTAVAIL;
1500 }
1501
1502 if (!data)
1503 goto out;
1504
1505 if (data[IFLA_GRE_REMOTE]) {
1506 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
1507 if (!daddr)
1508 return -EINVAL;
1509 }
1510
1511 out:
1512 return ipgre_tunnel_validate(tb, data);
1513 }
1514
1515 static void ipgre_netlink_parms(struct nlattr *data[],
1516 struct ip_tunnel_parm *parms)
1517 {
1518 memset(parms, 0, sizeof(*parms));
1519
1520 parms->iph.protocol = IPPROTO_GRE;
1521
1522 if (!data)
1523 return;
1524
1525 if (data[IFLA_GRE_LINK])
1526 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1527
1528 if (data[IFLA_GRE_IFLAGS])
1529 parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]);
1530
1531 if (data[IFLA_GRE_OFLAGS])
1532 parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]);
1533
1534 if (data[IFLA_GRE_IKEY])
1535 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1536
1537 if (data[IFLA_GRE_OKEY])
1538 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1539
1540 if (data[IFLA_GRE_LOCAL])
1541 parms->iph.saddr = nla_get_be32(data[IFLA_GRE_LOCAL]);
1542
1543 if (data[IFLA_GRE_REMOTE])
1544 parms->iph.daddr = nla_get_be32(data[IFLA_GRE_REMOTE]);
1545
1546 if (data[IFLA_GRE_TTL])
1547 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1548
1549 if (data[IFLA_GRE_TOS])
1550 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1551
1552 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC]))
1553 parms->iph.frag_off = htons(IP_DF);
1554 }
1555
1556 static int ipgre_tap_init(struct net_device *dev)
1557 {
1558 struct ip_tunnel *tunnel;
1559
1560 tunnel = netdev_priv(dev);
1561
1562 tunnel->dev = dev;
1563 strcpy(tunnel->parms.name, dev->name);
1564
1565 ipgre_tunnel_bind_dev(dev);
1566
1567 dev->tstats = alloc_percpu(struct pcpu_tstats);
1568 if (!dev->tstats)
1569 return -ENOMEM;
1570
1571 return 0;
1572 }
1573
1574 static const struct net_device_ops ipgre_tap_netdev_ops = {
1575 .ndo_init = ipgre_tap_init,
1576 .ndo_uninit = ipgre_tunnel_uninit,
1577 .ndo_start_xmit = ipgre_tunnel_xmit,
1578 .ndo_set_mac_address = eth_mac_addr,
1579 .ndo_validate_addr = eth_validate_addr,
1580 .ndo_change_mtu = ipgre_tunnel_change_mtu,
1581 .ndo_get_stats64 = ipgre_get_stats64,
1582 };
1583
1584 static void ipgre_tap_setup(struct net_device *dev)
1585 {
1586
1587 ether_setup(dev);
1588
1589 dev->netdev_ops = &ipgre_tap_netdev_ops;
1590 dev->destructor = ipgre_dev_free;
1591
1592 dev->iflink = 0;
1593 dev->features |= NETIF_F_NETNS_LOCAL;
1594 }
1595
1596 static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],
1597 struct nlattr *data[])
1598 {
1599 struct ip_tunnel *nt;
1600 struct net *net = dev_net(dev);
1601 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1602 int mtu;
1603 int err;
1604
1605 nt = netdev_priv(dev);
1606 ipgre_netlink_parms(data, &nt->parms);
1607
1608 if (ipgre_tunnel_find(net, &nt->parms, dev->type))
1609 return -EEXIST;
1610
1611 if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
1612 eth_hw_addr_random(dev);
1613
1614 mtu = ipgre_tunnel_bind_dev(dev);
1615 if (!tb[IFLA_MTU])
1616 dev->mtu = mtu;
1617
1618 /* Can use a lockless transmit, unless we generate output sequences */
1619 if (!(nt->parms.o_flags & GRE_SEQ))
1620 dev->features |= NETIF_F_LLTX;
1621
1622 err = register_netdevice(dev);
1623 if (err)
1624 goto out;
1625
1626 dev_hold(dev);
1627 ipgre_tunnel_link(ign, nt);
1628
1629 out:
1630 return err;
1631 }
1632
1633 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1634 struct nlattr *data[])
1635 {
1636 struct ip_tunnel *t, *nt;
1637 struct net *net = dev_net(dev);
1638 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1639 struct ip_tunnel_parm p;
1640 int mtu;
1641
1642 if (dev == ign->fb_tunnel_dev)
1643 return -EINVAL;
1644
1645 nt = netdev_priv(dev);
1646 ipgre_netlink_parms(data, &p);
1647
1648 t = ipgre_tunnel_locate(net, &p, 0);
1649
1650 if (t) {
1651 if (t->dev != dev)
1652 return -EEXIST;
1653 } else {
1654 t = nt;
1655
1656 if (dev->type != ARPHRD_ETHER) {
1657 unsigned int nflags = 0;
1658
1659 if (ipv4_is_multicast(p.iph.daddr))
1660 nflags = IFF_BROADCAST;
1661 else if (p.iph.daddr)
1662 nflags = IFF_POINTOPOINT;
1663
1664 if ((dev->flags ^ nflags) &
1665 (IFF_POINTOPOINT | IFF_BROADCAST))
1666 return -EINVAL;
1667 }
1668
1669 ipgre_tunnel_unlink(ign, t);
1670 t->parms.iph.saddr = p.iph.saddr;
1671 t->parms.iph.daddr = p.iph.daddr;
1672 t->parms.i_key = p.i_key;
1673 if (dev->type != ARPHRD_ETHER) {
1674 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1675 memcpy(dev->broadcast, &p.iph.daddr, 4);
1676 }
1677 ipgre_tunnel_link(ign, t);
1678 netdev_state_change(dev);
1679 }
1680
1681 t->parms.o_key = p.o_key;
1682 t->parms.iph.ttl = p.iph.ttl;
1683 t->parms.iph.tos = p.iph.tos;
1684 t->parms.iph.frag_off = p.iph.frag_off;
1685
1686 if (t->parms.link != p.link) {
1687 t->parms.link = p.link;
1688 mtu = ipgre_tunnel_bind_dev(dev);
1689 if (!tb[IFLA_MTU])
1690 dev->mtu = mtu;
1691 netdev_state_change(dev);
1692 }
1693
1694 return 0;
1695 }
1696
1697 static size_t ipgre_get_size(const struct net_device *dev)
1698 {
1699 return
1700 /* IFLA_GRE_LINK */
1701 nla_total_size(4) +
1702 /* IFLA_GRE_IFLAGS */
1703 nla_total_size(2) +
1704 /* IFLA_GRE_OFLAGS */
1705 nla_total_size(2) +
1706 /* IFLA_GRE_IKEY */
1707 nla_total_size(4) +
1708 /* IFLA_GRE_OKEY */
1709 nla_total_size(4) +
1710 /* IFLA_GRE_LOCAL */
1711 nla_total_size(4) +
1712 /* IFLA_GRE_REMOTE */
1713 nla_total_size(4) +
1714 /* IFLA_GRE_TTL */
1715 nla_total_size(1) +
1716 /* IFLA_GRE_TOS */
1717 nla_total_size(1) +
1718 /* IFLA_GRE_PMTUDISC */
1719 nla_total_size(1) +
1720 0;
1721 }
1722
1723 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1724 {
1725 struct ip_tunnel *t = netdev_priv(dev);
1726 struct ip_tunnel_parm *p = &t->parms;
1727
1728 if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
1729 nla_put_be16(skb, IFLA_GRE_IFLAGS, p->i_flags) ||
1730 nla_put_be16(skb, IFLA_GRE_OFLAGS, p->o_flags) ||
1731 nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
1732 nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
1733 nla_put_be32(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
1734 nla_put_be32(skb, IFLA_GRE_REMOTE, p->iph.daddr) ||
1735 nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) ||
1736 nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) ||
1737 nla_put_u8(skb, IFLA_GRE_PMTUDISC,
1738 !!(p->iph.frag_off & htons(IP_DF))))
1739 goto nla_put_failure;
1740 return 0;
1741
1742 nla_put_failure:
1743 return -EMSGSIZE;
1744 }
1745
1746 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1747 [IFLA_GRE_LINK] = { .type = NLA_U32 },
1748 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 },
1749 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 },
1750 [IFLA_GRE_IKEY] = { .type = NLA_U32 },
1751 [IFLA_GRE_OKEY] = { .type = NLA_U32 },
1752 [IFLA_GRE_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
1753 [IFLA_GRE_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
1754 [IFLA_GRE_TTL] = { .type = NLA_U8 },
1755 [IFLA_GRE_TOS] = { .type = NLA_U8 },
1756 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 },
1757 };
1758
1759 static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1760 .kind = "gre",
1761 .maxtype = IFLA_GRE_MAX,
1762 .policy = ipgre_policy,
1763 .priv_size = sizeof(struct ip_tunnel),
1764 .setup = ipgre_tunnel_setup,
1765 .validate = ipgre_tunnel_validate,
1766 .newlink = ipgre_newlink,
1767 .changelink = ipgre_changelink,
1768 .get_size = ipgre_get_size,
1769 .fill_info = ipgre_fill_info,
1770 };
1771
1772 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1773 .kind = "gretap",
1774 .maxtype = IFLA_GRE_MAX,
1775 .policy = ipgre_policy,
1776 .priv_size = sizeof(struct ip_tunnel),
1777 .setup = ipgre_tap_setup,
1778 .validate = ipgre_tap_validate,
1779 .newlink = ipgre_newlink,
1780 .changelink = ipgre_changelink,
1781 .get_size = ipgre_get_size,
1782 .fill_info = ipgre_fill_info,
1783 };
1784
1785 /*
1786 * And now the modules code and kernel interface.
1787 */
1788
1789 static int __init ipgre_init(void)
1790 {
1791 int err;
1792
1793 pr_info("GRE over IPv4 tunneling driver\n");
1794
1795 err = register_pernet_device(&ipgre_net_ops);
1796 if (err < 0)
1797 return err;
1798
1799 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
1800 if (err < 0) {
1801 pr_info("%s: can't add protocol\n", __func__);
1802 goto add_proto_failed;
1803 }
1804
1805 err = rtnl_link_register(&ipgre_link_ops);
1806 if (err < 0)
1807 goto rtnl_link_failed;
1808
1809 err = rtnl_link_register(&ipgre_tap_ops);
1810 if (err < 0)
1811 goto tap_ops_failed;
1812
1813 out:
1814 return err;
1815
1816 tap_ops_failed:
1817 rtnl_link_unregister(&ipgre_link_ops);
1818 rtnl_link_failed:
1819 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1820 add_proto_failed:
1821 unregister_pernet_device(&ipgre_net_ops);
1822 goto out;
1823 }
1824
1825 static void __exit ipgre_fini(void)
1826 {
1827 rtnl_link_unregister(&ipgre_tap_ops);
1828 rtnl_link_unregister(&ipgre_link_ops);
1829 if (gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0)
1830 pr_info("%s: can't remove protocol\n", __func__);
1831 unregister_pernet_device(&ipgre_net_ops);
1832 }
1833
1834 module_init(ipgre_init);
1835 module_exit(ipgre_fini);
1836 MODULE_LICENSE("GPL");
1837 MODULE_ALIAS_RTNL_LINK("gre");
1838 MODULE_ALIAS_RTNL_LINK("gretap");
1839 MODULE_ALIAS_NETDEV("gre0");
CRIS linux kernel tree