projects / deliverable / linux.git / blob
? search:


b9abf265c2f83d6f277f2044784b902f99d688ad
[deliverable/linux.git] / net / ipv4 / ip_gre.c
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 struct rtnl_link_ops ipgre_link_ops __read_mostly;
124 static int ipgre_tunnel_init(struct net_device *dev);
125 static void ipgre_tunnel_setup(struct net_device *dev);
126 static int ipgre_tunnel_bind_dev(struct net_device *dev);
127
128 /* Fallback tunnel: no source, no destination, no key, no options */
129
130 #define HASH_SIZE 16
131
132 static int ipgre_net_id __read_mostly;
133 struct ipgre_net {
134 struct ip_tunnel __rcu *tunnels[4][HASH_SIZE];
135
136 struct net_device *fb_tunnel_dev;
137 };
138
139 /* Tunnel hash table */
140
141 /*
142 4 hash tables:
143
144 3: (remote,local)
145 2: (remote,*)
146 1: (*,local)
147 0: (*,*)
148
149 We require exact key match i.e. if a key is present in packet
150 it will match only tunnel with the same key; if it is not present,
151 it will match only keyless tunnel.
152
153 All keysless packets, if not matched configured keyless tunnels
154 will match fallback tunnel.
155 */
156
157 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
158
159 #define tunnels_r_l tunnels[3]
160 #define tunnels_r tunnels[2]
161 #define tunnels_l tunnels[1]
162 #define tunnels_wc tunnels[0]
163 /*
164 * Locking : hash tables are protected by RCU and RTNL
165 */
166
167 #define for_each_ip_tunnel_rcu(start) \
168 for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
169
170 /* often modified stats are per cpu, other are shared (netdev->stats) */
171 struct pcpu_tstats {
172 u64 rx_packets;
173 u64 rx_bytes;
174 u64 tx_packets;
175 u64 tx_bytes;
176 struct u64_stats_sync syncp;
177 };
178
179 static struct rtnl_link_stats64 *ipgre_get_stats64(struct net_device *dev,
180 struct rtnl_link_stats64 *tot)
181 {
182 int i;
183
184 for_each_possible_cpu(i) {
185 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
186 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
187 unsigned int start;
188
189 do {
190 start = u64_stats_fetch_begin_bh(&tstats->syncp);
191 rx_packets = tstats->rx_packets;
192 tx_packets = tstats->tx_packets;
193 rx_bytes = tstats->rx_bytes;
194 tx_bytes = tstats->tx_bytes;
195 } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
196
197 tot->rx_packets += rx_packets;
198 tot->tx_packets += tx_packets;
199 tot->rx_bytes += rx_bytes;
200 tot->tx_bytes += tx_bytes;
201 }
202
203 tot->multicast = dev->stats.multicast;
204 tot->rx_crc_errors = dev->stats.rx_crc_errors;
205 tot->rx_fifo_errors = dev->stats.rx_fifo_errors;
206 tot->rx_length_errors = dev->stats.rx_length_errors;
207 tot->rx_errors = dev->stats.rx_errors;
208 tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
209 tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
210 tot->tx_dropped = dev->stats.tx_dropped;
211 tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
212 tot->tx_errors = dev->stats.tx_errors;
213
214 return tot;
215 }
216
217 /* Given src, dst and key, find appropriate for input tunnel. */
218
219 static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev,
220 __be32 remote, __be32 local,
221 __be32 key, __be16 gre_proto)
222 {
223 struct net *net = dev_net(dev);
224 int link = dev->ifindex;
225 unsigned int h0 = HASH(remote);
226 unsigned int h1 = HASH(key);
227 struct ip_tunnel *t, *cand = NULL;
228 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
229 int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
230 ARPHRD_ETHER : ARPHRD_IPGRE;
231 int score, cand_score = 4;
232
233 for_each_ip_tunnel_rcu(ign->tunnels_r_l[h0 ^ h1]) {
234 if (local != t->parms.iph.saddr ||
235 remote != t->parms.iph.daddr ||
236 key != t->parms.i_key ||
237 !(t->dev->flags & IFF_UP))
238 continue;
239
240 if (t->dev->type != ARPHRD_IPGRE &&
241 t->dev->type != dev_type)
242 continue;
243
244 score = 0;
245 if (t->parms.link != link)
246 score |= 1;
247 if (t->dev->type != dev_type)
248 score |= 2;
249 if (score == 0)
250 return t;
251
252 if (score < cand_score) {
253 cand = t;
254 cand_score = score;
255 }
256 }
257
258 for_each_ip_tunnel_rcu(ign->tunnels_r[h0 ^ h1]) {
259 if (remote != t->parms.iph.daddr ||
260 key != t->parms.i_key ||
261 !(t->dev->flags & IFF_UP))
262 continue;
263
264 if (t->dev->type != ARPHRD_IPGRE &&
265 t->dev->type != dev_type)
266 continue;
267
268 score = 0;
269 if (t->parms.link != link)
270 score |= 1;
271 if (t->dev->type != dev_type)
272 score |= 2;
273 if (score == 0)
274 return t;
275
276 if (score < cand_score) {
277 cand = t;
278 cand_score = score;
279 }
280 }
281
282 for_each_ip_tunnel_rcu(ign->tunnels_l[h1]) {
283 if ((local != t->parms.iph.saddr &&
284 (local != t->parms.iph.daddr ||
285 !ipv4_is_multicast(local))) ||
286 key != t->parms.i_key ||
287 !(t->dev->flags & IFF_UP))
288 continue;
289
290 if (t->dev->type != ARPHRD_IPGRE &&
291 t->dev->type != dev_type)
292 continue;
293
294 score = 0;
295 if (t->parms.link != link)
296 score |= 1;
297 if (t->dev->type != dev_type)
298 score |= 2;
299 if (score == 0)
300 return t;
301
302 if (score < cand_score) {
303 cand = t;
304 cand_score = score;
305 }
306 }
307
308 for_each_ip_tunnel_rcu(ign->tunnels_wc[h1]) {
309 if (t->parms.i_key != key ||
310 !(t->dev->flags & IFF_UP))
311 continue;
312
313 if (t->dev->type != ARPHRD_IPGRE &&
314 t->dev->type != dev_type)
315 continue;
316
317 score = 0;
318 if (t->parms.link != link)
319 score |= 1;
320 if (t->dev->type != dev_type)
321 score |= 2;
322 if (score == 0)
323 return t;
324
325 if (score < cand_score) {
326 cand = t;
327 cand_score = score;
328 }
329 }
330
331 if (cand != NULL)
332 return cand;
333
334 dev = ign->fb_tunnel_dev;
335 if (dev->flags & IFF_UP)
336 return netdev_priv(dev);
337
338 return NULL;
339 }
340
341 static struct ip_tunnel __rcu **__ipgre_bucket(struct ipgre_net *ign,
342 struct ip_tunnel_parm *parms)
343 {
344 __be32 remote = parms->iph.daddr;
345 __be32 local = parms->iph.saddr;
346 __be32 key = parms->i_key;
347 unsigned int h = HASH(key);
348 int prio = 0;
349
350 if (local)
351 prio |= 1;
352 if (remote && !ipv4_is_multicast(remote)) {
353 prio |= 2;
354 h ^= HASH(remote);
355 }
356
357 return &ign->tunnels[prio][h];
358 }
359
360 static inline struct ip_tunnel __rcu **ipgre_bucket(struct ipgre_net *ign,
361 struct ip_tunnel *t)
362 {
363 return __ipgre_bucket(ign, &t->parms);
364 }
365
366 static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t)
367 {
368 struct ip_tunnel __rcu **tp = ipgre_bucket(ign, t);
369
370 rcu_assign_pointer(t->next, rtnl_dereference(*tp));
371 rcu_assign_pointer(*tp, t);
372 }
373
374 static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t)
375 {
376 struct ip_tunnel __rcu **tp;
377 struct ip_tunnel *iter;
378
379 for (tp = ipgre_bucket(ign, t);
380 (iter = rtnl_dereference(*tp)) != NULL;
381 tp = &iter->next) {
382 if (t == iter) {
383 rcu_assign_pointer(*tp, t->next);
384 break;
385 }
386 }
387 }
388
389 static struct ip_tunnel *ipgre_tunnel_find(struct net *net,
390 struct ip_tunnel_parm *parms,
391 int type)
392 {
393 __be32 remote = parms->iph.daddr;
394 __be32 local = parms->iph.saddr;
395 __be32 key = parms->i_key;
396 int link = parms->link;
397 struct ip_tunnel *t;
398 struct ip_tunnel __rcu **tp;
399 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
400
401 for (tp = __ipgre_bucket(ign, parms);
402 (t = rtnl_dereference(*tp)) != NULL;
403 tp = &t->next)
404 if (local == t->parms.iph.saddr &&
405 remote == t->parms.iph.daddr &&
406 key == t->parms.i_key &&
407 link == t->parms.link &&
408 type == t->dev->type)
409 break;
410
411 return t;
412 }
413
414 static struct ip_tunnel *ipgre_tunnel_locate(struct net *net,
415 struct ip_tunnel_parm *parms, int create)
416 {
417 struct ip_tunnel *t, *nt;
418 struct net_device *dev;
419 char name[IFNAMSIZ];
420 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
421
422 t = ipgre_tunnel_find(net, parms, ARPHRD_IPGRE);
423 if (t || !create)
424 return t;
425
426 if (parms->name[0])
427 strlcpy(name, parms->name, IFNAMSIZ);
428 else
429 strcpy(name, "gre%d");
430
431 dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup);
432 if (!dev)
433 return NULL;
434
435 dev_net_set(dev, net);
436
437 nt = netdev_priv(dev);
438 nt->parms = *parms;
439 dev->rtnl_link_ops = &ipgre_link_ops;
440
441 dev->mtu = ipgre_tunnel_bind_dev(dev);
442
443 if (register_netdevice(dev) < 0)
444 goto failed_free;
445
446 /* Can use a lockless transmit, unless we generate output sequences */
447 if (!(nt->parms.o_flags & GRE_SEQ))
448 dev->features |= NETIF_F_LLTX;
449
450 dev_hold(dev);
451 ipgre_tunnel_link(ign, nt);
452 return nt;
453
454 failed_free:
455 free_netdev(dev);
456 return NULL;
457 }
458
459 static void ipgre_tunnel_uninit(struct net_device *dev)
460 {
461 struct net *net = dev_net(dev);
462 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
463
464 ipgre_tunnel_unlink(ign, netdev_priv(dev));
465 dev_put(dev);
466 }
467
468
469 static void ipgre_err(struct sk_buff *skb, u32 info)
470 {
471
472 /* All the routers (except for Linux) return only
473 8 bytes of packet payload. It means, that precise relaying of
474 ICMP in the real Internet is absolutely infeasible.
475
476 Moreover, Cisco "wise men" put GRE key to the third word
477 in GRE header. It makes impossible maintaining even soft state for keyed
478 GRE tunnels with enabled checksum. Tell them "thank you".
479
480 Well, I wonder, rfc1812 was written by Cisco employee,
481 what the hell these idiots break standards established
482 by themselves???
483 */
484
485 const struct iphdr *iph = (const struct iphdr *)skb->data;
486 __be16 *p = (__be16*)(skb->data+(iph->ihl<<2));
487 int grehlen = (iph->ihl<<2) + 4;
488 const int type = icmp_hdr(skb)->type;
489 const int code = icmp_hdr(skb)->code;
490 struct ip_tunnel *t;
491 __be16 flags;
492
493 flags = p[0];
494 if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
495 if (flags&(GRE_VERSION|GRE_ROUTING))
496 return;
497 if (flags&GRE_KEY) {
498 grehlen += 4;
499 if (flags&GRE_CSUM)
500 grehlen += 4;
501 }
502 }
503
504 /* If only 8 bytes returned, keyed message will be dropped here */
505 if (skb_headlen(skb) < grehlen)
506 return;
507
508 switch (type) {
509 default:
510 case ICMP_PARAMETERPROB:
511 return;
512
513 case ICMP_DEST_UNREACH:
514 switch (code) {
515 case ICMP_SR_FAILED:
516 case ICMP_PORT_UNREACH:
517 /* Impossible event. */
518 return;
519 case ICMP_FRAG_NEEDED:
520 /* Soft state for pmtu is maintained by IP core. */
521 return;
522 default:
523 /* All others are translated to HOST_UNREACH.
524 rfc2003 contains "deep thoughts" about NET_UNREACH,
525 I believe they are just ether pollution. --ANK
526 */
527 break;
528 }
529 break;
530 case ICMP_TIME_EXCEEDED:
531 if (code != ICMP_EXC_TTL)
532 return;
533 break;
534 }
535
536 rcu_read_lock();
537 t = ipgre_tunnel_lookup(skb->dev, iph->daddr, iph->saddr,
538 flags & GRE_KEY ?
539 *(((__be32 *)p) + (grehlen / 4) - 1) : 0,
540 p[1]);
541 if (t == NULL || t->parms.iph.daddr == 0 ||
542 ipv4_is_multicast(t->parms.iph.daddr))
543 goto out;
544
545 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
546 goto out;
547
548 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
549 t->err_count++;
550 else
551 t->err_count = 1;
552 t->err_time = jiffies;
553 out:
554 rcu_read_unlock();
555 }
556
557 static inline void ipgre_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
558 {
559 if (INET_ECN_is_ce(iph->tos)) {
560 if (skb->protocol == htons(ETH_P_IP)) {
561 IP_ECN_set_ce(ip_hdr(skb));
562 } else if (skb->protocol == htons(ETH_P_IPV6)) {
563 IP6_ECN_set_ce(ipv6_hdr(skb));
564 }
565 }
566 }
567
568 static inline u8
569 ipgre_ecn_encapsulate(u8 tos, const struct iphdr *old_iph, struct sk_buff *skb)
570 {
571 u8 inner = 0;
572 if (skb->protocol == htons(ETH_P_IP))
573 inner = old_iph->tos;
574 else if (skb->protocol == htons(ETH_P_IPV6))
575 inner = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
576 return INET_ECN_encapsulate(tos, inner);
577 }
578
579 static int ipgre_rcv(struct sk_buff *skb)
580 {
581 const struct iphdr *iph;
582 u8 *h;
583 __be16 flags;
584 __sum16 csum = 0;
585 __be32 key = 0;
586 u32 seqno = 0;
587 struct ip_tunnel *tunnel;
588 int offset = 4;
589 __be16 gre_proto;
590
591 if (!pskb_may_pull(skb, 16))
592 goto drop_nolock;
593
594 iph = ip_hdr(skb);
595 h = skb->data;
596 flags = *(__be16*)h;
597
598 if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
599 /* - Version must be 0.
600 - We do not support routing headers.
601 */
602 if (flags&(GRE_VERSION|GRE_ROUTING))
603 goto drop_nolock;
604
605 if (flags&GRE_CSUM) {
606 switch (skb->ip_summed) {
607 case CHECKSUM_COMPLETE:
608 csum = csum_fold(skb->csum);
609 if (!csum)
610 break;
611 /* fall through */
612 case CHECKSUM_NONE:
613 skb->csum = 0;
614 csum = __skb_checksum_complete(skb);
615 skb->ip_summed = CHECKSUM_COMPLETE;
616 }
617 offset += 4;
618 }
619 if (flags&GRE_KEY) {
620 key = *(__be32*)(h + offset);
621 offset += 4;
622 }
623 if (flags&GRE_SEQ) {
624 seqno = ntohl(*(__be32*)(h + offset));
625 offset += 4;
626 }
627 }
628
629 gre_proto = *(__be16 *)(h + 2);
630
631 rcu_read_lock();
632 if ((tunnel = ipgre_tunnel_lookup(skb->dev,
633 iph->saddr, iph->daddr, key,
634 gre_proto))) {
635 struct pcpu_tstats *tstats;
636
637 secpath_reset(skb);
638
639 skb->protocol = gre_proto;
640 /* WCCP version 1 and 2 protocol decoding.
641 * - Change protocol to IP
642 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
643 */
644 if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
645 skb->protocol = htons(ETH_P_IP);
646 if ((*(h + offset) & 0xF0) != 0x40)
647 offset += 4;
648 }
649
650 skb->mac_header = skb->network_header;
651 __pskb_pull(skb, offset);
652 skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
653 skb->pkt_type = PACKET_HOST;
654 #ifdef CONFIG_NET_IPGRE_BROADCAST
655 if (ipv4_is_multicast(iph->daddr)) {
656 /* Looped back packet, drop it! */
657 if (rt_is_output_route(skb_rtable(skb)))
658 goto drop;
659 tunnel->dev->stats.multicast++;
660 skb->pkt_type = PACKET_BROADCAST;
661 }
662 #endif
663
664 if (((flags&GRE_CSUM) && csum) ||
665 (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
666 tunnel->dev->stats.rx_crc_errors++;
667 tunnel->dev->stats.rx_errors++;
668 goto drop;
669 }
670 if (tunnel->parms.i_flags&GRE_SEQ) {
671 if (!(flags&GRE_SEQ) ||
672 (tunnel->i_seqno && (s32)(seqno - tunnel->i_seqno) < 0)) {
673 tunnel->dev->stats.rx_fifo_errors++;
674 tunnel->dev->stats.rx_errors++;
675 goto drop;
676 }
677 tunnel->i_seqno = seqno + 1;
678 }
679
680 /* Warning: All skb pointers will be invalidated! */
681 if (tunnel->dev->type == ARPHRD_ETHER) {
682 if (!pskb_may_pull(skb, ETH_HLEN)) {
683 tunnel->dev->stats.rx_length_errors++;
684 tunnel->dev->stats.rx_errors++;
685 goto drop;
686 }
687
688 iph = ip_hdr(skb);
689 skb->protocol = eth_type_trans(skb, tunnel->dev);
690 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
691 }
692
693 tstats = this_cpu_ptr(tunnel->dev->tstats);
694 u64_stats_update_begin(&tstats->syncp);
695 tstats->rx_packets++;
696 tstats->rx_bytes += skb->len;
697 u64_stats_update_end(&tstats->syncp);
698
699 __skb_tunnel_rx(skb, tunnel->dev);
700
701 skb_reset_network_header(skb);
702 ipgre_ecn_decapsulate(iph, skb);
703
704 netif_rx(skb);
705
706 rcu_read_unlock();
707 return 0;
708 }
709 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
710
711 drop:
712 rcu_read_unlock();
713 drop_nolock:
714 kfree_skb(skb);
715 return 0;
716 }
717
718 static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
719 {
720 struct ip_tunnel *tunnel = netdev_priv(dev);
721 struct pcpu_tstats *tstats;
722 const struct iphdr *old_iph = ip_hdr(skb);
723 const struct iphdr *tiph;
724 struct flowi4 fl4;
725 u8 tos;
726 __be16 df;
727 struct rtable *rt; /* Route to the other host */
728 struct net_device *tdev; /* Device to other host */
729 struct iphdr *iph; /* Our new IP header */
730 unsigned int max_headroom; /* The extra header space needed */
731 int gre_hlen;
732 __be32 dst;
733 int mtu;
734
735 if (dev->type == ARPHRD_ETHER)
736 IPCB(skb)->flags = 0;
737
738 if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
739 gre_hlen = 0;
740 tiph = (const struct iphdr *)skb->data;
741 } else {
742 gre_hlen = tunnel->hlen;
743 tiph = &tunnel->parms.iph;
744 }
745
746 if ((dst = tiph->daddr) == 0) {
747 /* NBMA tunnel */
748
749 if (skb_dst(skb) == NULL) {
750 dev->stats.tx_fifo_errors++;
751 goto tx_error;
752 }
753
754 if (skb->protocol == htons(ETH_P_IP)) {
755 rt = skb_rtable(skb);
756 dst = rt->rt_gateway;
757 }
758 #if IS_ENABLED(CONFIG_IPV6)
759 else if (skb->protocol == htons(ETH_P_IPV6)) {
760 const struct in6_addr *addr6;
761 struct neighbour *neigh;
762 bool do_tx_error_icmp;
763 int addr_type;
764
765 neigh = dst_neigh_lookup(skb_dst(skb), &ipv6_hdr(skb)->daddr);
766 if (neigh == NULL)
767 goto tx_error;
768
769 addr6 = (const struct in6_addr *)&neigh->primary_key;
770 addr_type = ipv6_addr_type(addr6);
771
772 if (addr_type == IPV6_ADDR_ANY) {
773 addr6 = &ipv6_hdr(skb)->daddr;
774 addr_type = ipv6_addr_type(addr6);
775 }
776
777 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
778 do_tx_error_icmp = true;
779 else {
780 do_tx_error_icmp = false;
781 dst = addr6->s6_addr32[3];
782 }
783 neigh_release(neigh);
784 if (do_tx_error_icmp)
785 goto tx_error_icmp;
786 }
787 #endif
788 else
789 goto tx_error;
790 }
791
792 tos = tiph->tos;
793 if (tos == 1) {
794 tos = 0;
795 if (skb->protocol == htons(ETH_P_IP))
796 tos = old_iph->tos;
797 else if (skb->protocol == htons(ETH_P_IPV6))
798 tos = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
799 }
800
801 rt = ip_route_output_gre(dev_net(dev), &fl4, dst, tiph->saddr,
802 tunnel->parms.o_key, RT_TOS(tos),
803 tunnel->parms.link);
804 if (IS_ERR(rt)) {
805 dev->stats.tx_carrier_errors++;
806 goto tx_error;
807 }
808 tdev = rt->dst.dev;
809
810 if (tdev == dev) {
811 ip_rt_put(rt);
812 dev->stats.collisions++;
813 goto tx_error;
814 }
815
816 df = tiph->frag_off;
817 if (df)
818 mtu = dst_mtu(&rt->dst) - dev->hard_header_len - tunnel->hlen;
819 else
820 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
821
822 if (skb_dst(skb))
823 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
824
825 if (skb->protocol == htons(ETH_P_IP)) {
826 df |= (old_iph->frag_off&htons(IP_DF));
827
828 if ((old_iph->frag_off&htons(IP_DF)) &&
829 mtu < ntohs(old_iph->tot_len)) {
830 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
831 ip_rt_put(rt);
832 goto tx_error;
833 }
834 }
835 #if IS_ENABLED(CONFIG_IPV6)
836 else if (skb->protocol == htons(ETH_P_IPV6)) {
837 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
838
839 if (rt6 && mtu < dst_mtu(skb_dst(skb)) && mtu >= IPV6_MIN_MTU) {
840 if ((tunnel->parms.iph.daddr &&
841 !ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
842 rt6->rt6i_dst.plen == 128) {
843 rt6->rt6i_flags |= RTF_MODIFIED;
844 dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
845 }
846 }
847
848 if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) {
849 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
850 ip_rt_put(rt);
851 goto tx_error;
852 }
853 }
854 #endif
855
856 if (tunnel->err_count > 0) {
857 if (time_before(jiffies,
858 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
859 tunnel->err_count--;
860
861 dst_link_failure(skb);
862 } else
863 tunnel->err_count = 0;
864 }
865
866 max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen + rt->dst.header_len;
867
868 if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
869 (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
870 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
871 if (max_headroom > dev->needed_headroom)
872 dev->needed_headroom = max_headroom;
873 if (!new_skb) {
874 ip_rt_put(rt);
875 dev->stats.tx_dropped++;
876 dev_kfree_skb(skb);
877 return NETDEV_TX_OK;
878 }
879 if (skb->sk)
880 skb_set_owner_w(new_skb, skb->sk);
881 dev_kfree_skb(skb);
882 skb = new_skb;
883 old_iph = ip_hdr(skb);
884 }
885
886 skb_reset_transport_header(skb);
887 skb_push(skb, gre_hlen);
888 skb_reset_network_header(skb);
889 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
890 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
891 IPSKB_REROUTED);
892 skb_dst_drop(skb);
893 skb_dst_set(skb, &rt->dst);
894
895 /*
896 * Push down and install the IPIP header.
897 */
898
899 iph = ip_hdr(skb);
900 iph->version = 4;
901 iph->ihl = sizeof(struct iphdr) >> 2;
902 iph->frag_off = df;
903 iph->protocol = IPPROTO_GRE;
904 iph->tos = ipgre_ecn_encapsulate(tos, old_iph, skb);
905 iph->daddr = fl4.daddr;
906 iph->saddr = fl4.saddr;
907
908 if ((iph->ttl = tiph->ttl) == 0) {
909 if (skb->protocol == htons(ETH_P_IP))
910 iph->ttl = old_iph->ttl;
911 #if IS_ENABLED(CONFIG_IPV6)
912 else if (skb->protocol == htons(ETH_P_IPV6))
913 iph->ttl = ((const struct ipv6hdr *)old_iph)->hop_limit;
914 #endif
915 else
916 iph->ttl = ip4_dst_hoplimit(&rt->dst);
917 }
918
919 ((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags;
920 ((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ?
921 htons(ETH_P_TEB) : skb->protocol;
922
923 if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
924 __be32 *ptr = (__be32*)(((u8*)iph) + tunnel->hlen - 4);
925
926 if (tunnel->parms.o_flags&GRE_SEQ) {
927 ++tunnel->o_seqno;
928 *ptr = htonl(tunnel->o_seqno);
929 ptr--;
930 }
931 if (tunnel->parms.o_flags&GRE_KEY) {
932 *ptr = tunnel->parms.o_key;
933 ptr--;
934 }
935 if (tunnel->parms.o_flags&GRE_CSUM) {
936 *ptr = 0;
937 *(__sum16*)ptr = ip_compute_csum((void*)(iph+1), skb->len - sizeof(struct iphdr));
938 }
939 }
940
941 nf_reset(skb);
942 tstats = this_cpu_ptr(dev->tstats);
943 __IPTUNNEL_XMIT(tstats, &dev->stats);
944 return NETDEV_TX_OK;
945
946 #if IS_ENABLED(CONFIG_IPV6)
947 tx_error_icmp:
948 dst_link_failure(skb);
949 #endif
950 tx_error:
951 dev->stats.tx_errors++;
952 dev_kfree_skb(skb);
953 return NETDEV_TX_OK;
954 }
955
956 static int ipgre_tunnel_bind_dev(struct net_device *dev)
957 {
958 struct net_device *tdev = NULL;
959 struct ip_tunnel *tunnel;
960 const struct iphdr *iph;
961 int hlen = LL_MAX_HEADER;
962 int mtu = ETH_DATA_LEN;
963 int addend = sizeof(struct iphdr) + 4;
964
965 tunnel = netdev_priv(dev);
966 iph = &tunnel->parms.iph;
967
968 /* Guess output device to choose reasonable mtu and needed_headroom */
969
970 if (iph->daddr) {
971 struct flowi4 fl4;
972 struct rtable *rt;
973
974 rt = ip_route_output_gre(dev_net(dev), &fl4,
975 iph->daddr, iph->saddr,
976 tunnel->parms.o_key,
977 RT_TOS(iph->tos),
978 tunnel->parms.link);
979 if (!IS_ERR(rt)) {
980 tdev = rt->dst.dev;
981 ip_rt_put(rt);
982 }
983
984 if (dev->type != ARPHRD_ETHER)
985 dev->flags |= IFF_POINTOPOINT;
986 }
987
988 if (!tdev && tunnel->parms.link)
989 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
990
991 if (tdev) {
992 hlen = tdev->hard_header_len + tdev->needed_headroom;
993 mtu = tdev->mtu;
994 }
995 dev->iflink = tunnel->parms.link;
996
997 /* Precalculate GRE options length */
998 if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) {
999 if (tunnel->parms.o_flags&GRE_CSUM)
1000 addend += 4;
1001 if (tunnel->parms.o_flags&GRE_KEY)
1002 addend += 4;
1003 if (tunnel->parms.o_flags&GRE_SEQ)
1004 addend += 4;
1005 }
1006 dev->needed_headroom = addend + hlen;
1007 mtu -= dev->hard_header_len + addend;
1008
1009 if (mtu < 68)
1010 mtu = 68;
1011
1012 tunnel->hlen = addend;
1013
1014 return mtu;
1015 }
1016
1017 static int
1018 ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
1019 {
1020 int err = 0;
1021 struct ip_tunnel_parm p;
1022 struct ip_tunnel *t;
1023 struct net *net = dev_net(dev);
1024 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1025
1026 switch (cmd) {
1027 case SIOCGETTUNNEL:
1028 t = NULL;
1029 if (dev == ign->fb_tunnel_dev) {
1030 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1031 err = -EFAULT;
1032 break;
1033 }
1034 t = ipgre_tunnel_locate(net, &p, 0);
1035 }
1036 if (t == NULL)
1037 t = netdev_priv(dev);
1038 memcpy(&p, &t->parms, sizeof(p));
1039 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1040 err = -EFAULT;
1041 break;
1042
1043 case SIOCADDTUNNEL:
1044 case SIOCCHGTUNNEL:
1045 err = -EPERM;
1046 if (!capable(CAP_NET_ADMIN))
1047 goto done;
1048
1049 err = -EFAULT;
1050 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1051 goto done;
1052
1053 err = -EINVAL;
1054 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
1055 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
1056 ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
1057 goto done;
1058 if (p.iph.ttl)
1059 p.iph.frag_off |= htons(IP_DF);
1060
1061 if (!(p.i_flags&GRE_KEY))
1062 p.i_key = 0;
1063 if (!(p.o_flags&GRE_KEY))
1064 p.o_key = 0;
1065
1066 t = ipgre_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1067
1068 if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1069 if (t != NULL) {
1070 if (t->dev != dev) {
1071 err = -EEXIST;
1072 break;
1073 }
1074 } else {
1075 unsigned int nflags = 0;
1076
1077 t = netdev_priv(dev);
1078
1079 if (ipv4_is_multicast(p.iph.daddr))
1080 nflags = IFF_BROADCAST;
1081 else if (p.iph.daddr)
1082 nflags = IFF_POINTOPOINT;
1083
1084 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
1085 err = -EINVAL;
1086 break;
1087 }
1088 ipgre_tunnel_unlink(ign, t);
1089 synchronize_net();
1090 t->parms.iph.saddr = p.iph.saddr;
1091 t->parms.iph.daddr = p.iph.daddr;
1092 t->parms.i_key = p.i_key;
1093 t->parms.o_key = p.o_key;
1094 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1095 memcpy(dev->broadcast, &p.iph.daddr, 4);
1096 ipgre_tunnel_link(ign, t);
1097 netdev_state_change(dev);
1098 }
1099 }
1100
1101 if (t) {
1102 err = 0;
1103 if (cmd == SIOCCHGTUNNEL) {
1104 t->parms.iph.ttl = p.iph.ttl;
1105 t->parms.iph.tos = p.iph.tos;
1106 t->parms.iph.frag_off = p.iph.frag_off;
1107 if (t->parms.link != p.link) {
1108 t->parms.link = p.link;
1109 dev->mtu = ipgre_tunnel_bind_dev(dev);
1110 netdev_state_change(dev);
1111 }
1112 }
1113 if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1114 err = -EFAULT;
1115 } else
1116 err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1117 break;
1118
1119 case SIOCDELTUNNEL:
1120 err = -EPERM;
1121 if (!capable(CAP_NET_ADMIN))
1122 goto done;
1123
1124 if (dev == ign->fb_tunnel_dev) {
1125 err = -EFAULT;
1126 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1127 goto done;
1128 err = -ENOENT;
1129 if ((t = ipgre_tunnel_locate(net, &p, 0)) == NULL)
1130 goto done;
1131 err = -EPERM;
1132 if (t == netdev_priv(ign->fb_tunnel_dev))
1133 goto done;
1134 dev = t->dev;
1135 }
1136 unregister_netdevice(dev);
1137 err = 0;
1138 break;
1139
1140 default:
1141 err = -EINVAL;
1142 }
1143
1144 done:
1145 return err;
1146 }
1147
1148 static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1149 {
1150 struct ip_tunnel *tunnel = netdev_priv(dev);
1151 if (new_mtu < 68 ||
1152 new_mtu > 0xFFF8 - dev->hard_header_len - tunnel->hlen)
1153 return -EINVAL;
1154 dev->mtu = new_mtu;
1155 return 0;
1156 }
1157
1158 /* Nice toy. Unfortunately, useless in real life :-)
1159 It allows to construct virtual multiprotocol broadcast "LAN"
1160 over the Internet, provided multicast routing is tuned.
1161
1162
1163 I have no idea was this bicycle invented before me,
1164 so that I had to set ARPHRD_IPGRE to a random value.
1165 I have an impression, that Cisco could make something similar,
1166 but this feature is apparently missing in IOS<=11.2(8).
1167
1168 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
1169 with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
1170
1171 ping -t 255 224.66.66.66
1172
1173 If nobody answers, mbone does not work.
1174
1175 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
1176 ip addr add 10.66.66.<somewhat>/24 dev Universe
1177 ifconfig Universe up
1178 ifconfig Universe add fe80::<Your_real_addr>/10
1179 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
1180 ftp 10.66.66.66
1181 ...
1182 ftp fec0:6666:6666::193.233.7.65
1183 ...
1184
1185 */
1186
1187 static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
1188 unsigned short type,
1189 const void *daddr, const void *saddr, unsigned int len)
1190 {
1191 struct ip_tunnel *t = netdev_priv(dev);
1192 struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
1193 __be16 *p = (__be16*)(iph+1);
1194
1195 memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
1196 p[0] = t->parms.o_flags;
1197 p[1] = htons(type);
1198
1199 /*
1200 * Set the source hardware address.
1201 */
1202
1203 if (saddr)
1204 memcpy(&iph->saddr, saddr, 4);
1205 if (daddr)
1206 memcpy(&iph->daddr, daddr, 4);
1207 if (iph->daddr)
1208 return t->hlen;
1209
1210 return -t->hlen;
1211 }
1212
1213 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
1214 {
1215 const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
1216 memcpy(haddr, &iph->saddr, 4);
1217 return 4;
1218 }
1219
1220 static const struct header_ops ipgre_header_ops = {
1221 .create = ipgre_header,
1222 .parse = ipgre_header_parse,
1223 };
1224
1225 #ifdef CONFIG_NET_IPGRE_BROADCAST
1226 static int ipgre_open(struct net_device *dev)
1227 {
1228 struct ip_tunnel *t = netdev_priv(dev);
1229
1230 if (ipv4_is_multicast(t->parms.iph.daddr)) {
1231 struct flowi4 fl4;
1232 struct rtable *rt;
1233
1234 rt = ip_route_output_gre(dev_net(dev), &fl4,
1235 t->parms.iph.daddr,
1236 t->parms.iph.saddr,
1237 t->parms.o_key,
1238 RT_TOS(t->parms.iph.tos),
1239 t->parms.link);
1240 if (IS_ERR(rt))
1241 return -EADDRNOTAVAIL;
1242 dev = rt->dst.dev;
1243 ip_rt_put(rt);
1244 if (__in_dev_get_rtnl(dev) == NULL)
1245 return -EADDRNOTAVAIL;
1246 t->mlink = dev->ifindex;
1247 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
1248 }
1249 return 0;
1250 }
1251
1252 static int ipgre_close(struct net_device *dev)
1253 {
1254 struct ip_tunnel *t = netdev_priv(dev);
1255
1256 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
1257 struct in_device *in_dev;
1258 in_dev = inetdev_by_index(dev_net(dev), t->mlink);
1259 if (in_dev)
1260 ip_mc_dec_group(in_dev, t->parms.iph.daddr);
1261 }
1262 return 0;
1263 }
1264
1265 #endif
1266
1267 static const struct net_device_ops ipgre_netdev_ops = {
1268 .ndo_init = ipgre_tunnel_init,
1269 .ndo_uninit = ipgre_tunnel_uninit,
1270 #ifdef CONFIG_NET_IPGRE_BROADCAST
1271 .ndo_open = ipgre_open,
1272 .ndo_stop = ipgre_close,
1273 #endif
1274 .ndo_start_xmit = ipgre_tunnel_xmit,
1275 .ndo_do_ioctl = ipgre_tunnel_ioctl,
1276 .ndo_change_mtu = ipgre_tunnel_change_mtu,
1277 .ndo_get_stats64 = ipgre_get_stats64,
1278 };
1279
1280 static void ipgre_dev_free(struct net_device *dev)
1281 {
1282 free_percpu(dev->tstats);
1283 free_netdev(dev);
1284 }
1285
1286 static void ipgre_tunnel_setup(struct net_device *dev)
1287 {
1288 dev->netdev_ops = &ipgre_netdev_ops;
1289 dev->destructor = ipgre_dev_free;
1290
1291 dev->type = ARPHRD_IPGRE;
1292 dev->needed_headroom = LL_MAX_HEADER + sizeof(struct iphdr) + 4;
1293 dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr) - 4;
1294 dev->flags = IFF_NOARP;
1295 dev->iflink = 0;
1296 dev->addr_len = 4;
1297 dev->features |= NETIF_F_NETNS_LOCAL;
1298 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1299 }
1300
1301 static int ipgre_tunnel_init(struct net_device *dev)
1302 {
1303 struct ip_tunnel *tunnel;
1304 struct iphdr *iph;
1305
1306 tunnel = netdev_priv(dev);
1307 iph = &tunnel->parms.iph;
1308
1309 tunnel->dev = dev;
1310 strcpy(tunnel->parms.name, dev->name);
1311
1312 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1313 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1314
1315 if (iph->daddr) {
1316 #ifdef CONFIG_NET_IPGRE_BROADCAST
1317 if (ipv4_is_multicast(iph->daddr)) {
1318 if (!iph->saddr)
1319 return -EINVAL;
1320 dev->flags = IFF_BROADCAST;
1321 dev->header_ops = &ipgre_header_ops;
1322 }
1323 #endif
1324 } else
1325 dev->header_ops = &ipgre_header_ops;
1326
1327 dev->tstats = alloc_percpu(struct pcpu_tstats);
1328 if (!dev->tstats)
1329 return -ENOMEM;
1330
1331 return 0;
1332 }
1333
1334 static void ipgre_fb_tunnel_init(struct net_device *dev)
1335 {
1336 struct ip_tunnel *tunnel = netdev_priv(dev);
1337 struct iphdr *iph = &tunnel->parms.iph;
1338
1339 tunnel->dev = dev;
1340 strcpy(tunnel->parms.name, dev->name);
1341
1342 iph->version = 4;
1343 iph->protocol = IPPROTO_GRE;
1344 iph->ihl = 5;
1345 tunnel->hlen = sizeof(struct iphdr) + 4;
1346
1347 dev_hold(dev);
1348 }
1349
1350
1351 static const struct gre_protocol ipgre_protocol = {
1352 .handler = ipgre_rcv,
1353 .err_handler = ipgre_err,
1354 };
1355
1356 static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head)
1357 {
1358 int prio;
1359
1360 for (prio = 0; prio < 4; prio++) {
1361 int h;
1362 for (h = 0; h < HASH_SIZE; h++) {
1363 struct ip_tunnel *t;
1364
1365 t = rtnl_dereference(ign->tunnels[prio][h]);
1366
1367 while (t != NULL) {
1368 unregister_netdevice_queue(t->dev, head);
1369 t = rtnl_dereference(t->next);
1370 }
1371 }
1372 }
1373 }
1374
1375 static int __net_init ipgre_init_net(struct net *net)
1376 {
1377 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1378 int err;
1379
1380 ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0",
1381 ipgre_tunnel_setup);
1382 if (!ign->fb_tunnel_dev) {
1383 err = -ENOMEM;
1384 goto err_alloc_dev;
1385 }
1386 dev_net_set(ign->fb_tunnel_dev, net);
1387
1388 ipgre_fb_tunnel_init(ign->fb_tunnel_dev);
1389 ign->fb_tunnel_dev->rtnl_link_ops = &ipgre_link_ops;
1390
1391 if ((err = register_netdev(ign->fb_tunnel_dev)))
1392 goto err_reg_dev;
1393
1394 rcu_assign_pointer(ign->tunnels_wc[0],
1395 netdev_priv(ign->fb_tunnel_dev));
1396 return 0;
1397
1398 err_reg_dev:
1399 ipgre_dev_free(ign->fb_tunnel_dev);
1400 err_alloc_dev:
1401 return err;
1402 }
1403
1404 static void __net_exit ipgre_exit_net(struct net *net)
1405 {
1406 struct ipgre_net *ign;
1407 LIST_HEAD(list);
1408
1409 ign = net_generic(net, ipgre_net_id);
1410 rtnl_lock();
1411 ipgre_destroy_tunnels(ign, &list);
1412 unregister_netdevice_many(&list);
1413 rtnl_unlock();
1414 }
1415
1416 static struct pernet_operations ipgre_net_ops = {
1417 .init = ipgre_init_net,
1418 .exit = ipgre_exit_net,
1419 .id = &ipgre_net_id,
1420 .size = sizeof(struct ipgre_net),
1421 };
1422
1423 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
1424 {
1425 __be16 flags;
1426
1427 if (!data)
1428 return 0;
1429
1430 flags = 0;
1431 if (data[IFLA_GRE_IFLAGS])
1432 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1433 if (data[IFLA_GRE_OFLAGS])
1434 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1435 if (flags & (GRE_VERSION|GRE_ROUTING))
1436 return -EINVAL;
1437
1438 return 0;
1439 }
1440
1441 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
1442 {
1443 __be32 daddr;
1444
1445 if (tb[IFLA_ADDRESS]) {
1446 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1447 return -EINVAL;
1448 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1449 return -EADDRNOTAVAIL;
1450 }
1451
1452 if (!data)
1453 goto out;
1454
1455 if (data[IFLA_GRE_REMOTE]) {
1456 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
1457 if (!daddr)
1458 return -EINVAL;
1459 }
1460
1461 out:
1462 return ipgre_tunnel_validate(tb, data);
1463 }
1464
1465 static void ipgre_netlink_parms(struct nlattr *data[],
1466 struct ip_tunnel_parm *parms)
1467 {
1468 memset(parms, 0, sizeof(*parms));
1469
1470 parms->iph.protocol = IPPROTO_GRE;
1471
1472 if (!data)
1473 return;
1474
1475 if (data[IFLA_GRE_LINK])
1476 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1477
1478 if (data[IFLA_GRE_IFLAGS])
1479 parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]);
1480
1481 if (data[IFLA_GRE_OFLAGS])
1482 parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]);
1483
1484 if (data[IFLA_GRE_IKEY])
1485 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1486
1487 if (data[IFLA_GRE_OKEY])
1488 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1489
1490 if (data[IFLA_GRE_LOCAL])
1491 parms->iph.saddr = nla_get_be32(data[IFLA_GRE_LOCAL]);
1492
1493 if (data[IFLA_GRE_REMOTE])
1494 parms->iph.daddr = nla_get_be32(data[IFLA_GRE_REMOTE]);
1495
1496 if (data[IFLA_GRE_TTL])
1497 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1498
1499 if (data[IFLA_GRE_TOS])
1500 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1501
1502 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC]))
1503 parms->iph.frag_off = htons(IP_DF);
1504 }
1505
1506 static int ipgre_tap_init(struct net_device *dev)
1507 {
1508 struct ip_tunnel *tunnel;
1509
1510 tunnel = netdev_priv(dev);
1511
1512 tunnel->dev = dev;
1513 strcpy(tunnel->parms.name, dev->name);
1514
1515 ipgre_tunnel_bind_dev(dev);
1516
1517 dev->tstats = alloc_percpu(struct pcpu_tstats);
1518 if (!dev->tstats)
1519 return -ENOMEM;
1520
1521 return 0;
1522 }
1523
1524 static const struct net_device_ops ipgre_tap_netdev_ops = {
1525 .ndo_init = ipgre_tap_init,
1526 .ndo_uninit = ipgre_tunnel_uninit,
1527 .ndo_start_xmit = ipgre_tunnel_xmit,
1528 .ndo_set_mac_address = eth_mac_addr,
1529 .ndo_validate_addr = eth_validate_addr,
1530 .ndo_change_mtu = ipgre_tunnel_change_mtu,
1531 .ndo_get_stats64 = ipgre_get_stats64,
1532 };
1533
1534 static void ipgre_tap_setup(struct net_device *dev)
1535 {
1536
1537 ether_setup(dev);
1538
1539 dev->netdev_ops = &ipgre_tap_netdev_ops;
1540 dev->destructor = ipgre_dev_free;
1541
1542 dev->iflink = 0;
1543 dev->features |= NETIF_F_NETNS_LOCAL;
1544 }
1545
1546 static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],
1547 struct nlattr *data[])
1548 {
1549 struct ip_tunnel *nt;
1550 struct net *net = dev_net(dev);
1551 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1552 int mtu;
1553 int err;
1554
1555 nt = netdev_priv(dev);
1556 ipgre_netlink_parms(data, &nt->parms);
1557
1558 if (ipgre_tunnel_find(net, &nt->parms, dev->type))
1559 return -EEXIST;
1560
1561 if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
1562 eth_hw_addr_random(dev);
1563
1564 mtu = ipgre_tunnel_bind_dev(dev);
1565 if (!tb[IFLA_MTU])
1566 dev->mtu = mtu;
1567
1568 /* Can use a lockless transmit, unless we generate output sequences */
1569 if (!(nt->parms.o_flags & GRE_SEQ))
1570 dev->features |= NETIF_F_LLTX;
1571
1572 err = register_netdevice(dev);
1573 if (err)
1574 goto out;
1575
1576 dev_hold(dev);
1577 ipgre_tunnel_link(ign, nt);
1578
1579 out:
1580 return err;
1581 }
1582
1583 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1584 struct nlattr *data[])
1585 {
1586 struct ip_tunnel *t, *nt;
1587 struct net *net = dev_net(dev);
1588 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1589 struct ip_tunnel_parm p;
1590 int mtu;
1591
1592 if (dev == ign->fb_tunnel_dev)
1593 return -EINVAL;
1594
1595 nt = netdev_priv(dev);
1596 ipgre_netlink_parms(data, &p);
1597
1598 t = ipgre_tunnel_locate(net, &p, 0);
1599
1600 if (t) {
1601 if (t->dev != dev)
1602 return -EEXIST;
1603 } else {
1604 t = nt;
1605
1606 if (dev->type != ARPHRD_ETHER) {
1607 unsigned int nflags = 0;
1608
1609 if (ipv4_is_multicast(p.iph.daddr))
1610 nflags = IFF_BROADCAST;
1611 else if (p.iph.daddr)
1612 nflags = IFF_POINTOPOINT;
1613
1614 if ((dev->flags ^ nflags) &
1615 (IFF_POINTOPOINT | IFF_BROADCAST))
1616 return -EINVAL;
1617 }
1618
1619 ipgre_tunnel_unlink(ign, t);
1620 t->parms.iph.saddr = p.iph.saddr;
1621 t->parms.iph.daddr = p.iph.daddr;
1622 t->parms.i_key = p.i_key;
1623 if (dev->type != ARPHRD_ETHER) {
1624 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1625 memcpy(dev->broadcast, &p.iph.daddr, 4);
1626 }
1627 ipgre_tunnel_link(ign, t);
1628 netdev_state_change(dev);
1629 }
1630
1631 t->parms.o_key = p.o_key;
1632 t->parms.iph.ttl = p.iph.ttl;
1633 t->parms.iph.tos = p.iph.tos;
1634 t->parms.iph.frag_off = p.iph.frag_off;
1635
1636 if (t->parms.link != p.link) {
1637 t->parms.link = p.link;
1638 mtu = ipgre_tunnel_bind_dev(dev);
1639 if (!tb[IFLA_MTU])
1640 dev->mtu = mtu;
1641 netdev_state_change(dev);
1642 }
1643
1644 return 0;
1645 }
1646
1647 static size_t ipgre_get_size(const struct net_device *dev)
1648 {
1649 return
1650 /* IFLA_GRE_LINK */
1651 nla_total_size(4) +
1652 /* IFLA_GRE_IFLAGS */
1653 nla_total_size(2) +
1654 /* IFLA_GRE_OFLAGS */
1655 nla_total_size(2) +
1656 /* IFLA_GRE_IKEY */
1657 nla_total_size(4) +
1658 /* IFLA_GRE_OKEY */
1659 nla_total_size(4) +
1660 /* IFLA_GRE_LOCAL */
1661 nla_total_size(4) +
1662 /* IFLA_GRE_REMOTE */
1663 nla_total_size(4) +
1664 /* IFLA_GRE_TTL */
1665 nla_total_size(1) +
1666 /* IFLA_GRE_TOS */
1667 nla_total_size(1) +
1668 /* IFLA_GRE_PMTUDISC */
1669 nla_total_size(1) +
1670 0;
1671 }
1672
1673 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1674 {
1675 struct ip_tunnel *t = netdev_priv(dev);
1676 struct ip_tunnel_parm *p = &t->parms;
1677
1678 if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
1679 nla_put_be16(skb, IFLA_GRE_IFLAGS, p->i_flags) ||
1680 nla_put_be16(skb, IFLA_GRE_OFLAGS, p->o_flags) ||
1681 nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
1682 nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
1683 nla_put_be32(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
1684 nla_put_be32(skb, IFLA_GRE_REMOTE, p->iph.daddr) ||
1685 nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) ||
1686 nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) ||
1687 nla_put_u8(skb, IFLA_GRE_PMTUDISC,
1688 !!(p->iph.frag_off & htons(IP_DF))))
1689 goto nla_put_failure;
1690 return 0;
1691
1692 nla_put_failure:
1693 return -EMSGSIZE;
1694 }
1695
1696 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1697 [IFLA_GRE_LINK] = { .type = NLA_U32 },
1698 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 },
1699 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 },
1700 [IFLA_GRE_IKEY] = { .type = NLA_U32 },
1701 [IFLA_GRE_OKEY] = { .type = NLA_U32 },
1702 [IFLA_GRE_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
1703 [IFLA_GRE_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
1704 [IFLA_GRE_TTL] = { .type = NLA_U8 },
1705 [IFLA_GRE_TOS] = { .type = NLA_U8 },
1706 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 },
1707 };
1708
1709 static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1710 .kind = "gre",
1711 .maxtype = IFLA_GRE_MAX,
1712 .policy = ipgre_policy,
1713 .priv_size = sizeof(struct ip_tunnel),
1714 .setup = ipgre_tunnel_setup,
1715 .validate = ipgre_tunnel_validate,
1716 .newlink = ipgre_newlink,
1717 .changelink = ipgre_changelink,
1718 .get_size = ipgre_get_size,
1719 .fill_info = ipgre_fill_info,
1720 };
1721
1722 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1723 .kind = "gretap",
1724 .maxtype = IFLA_GRE_MAX,
1725 .policy = ipgre_policy,
1726 .priv_size = sizeof(struct ip_tunnel),
1727 .setup = ipgre_tap_setup,
1728 .validate = ipgre_tap_validate,
1729 .newlink = ipgre_newlink,
1730 .changelink = ipgre_changelink,
1731 .get_size = ipgre_get_size,
1732 .fill_info = ipgre_fill_info,
1733 };
1734
1735 /*
1736 * And now the modules code and kernel interface.
1737 */
1738
1739 static int __init ipgre_init(void)
1740 {
1741 int err;
1742
1743 pr_info("GRE over IPv4 tunneling driver\n");
1744
1745 err = register_pernet_device(&ipgre_net_ops);
1746 if (err < 0)
1747 return err;
1748
1749 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
1750 if (err < 0) {
1751 pr_info("%s: can't add protocol\n", __func__);
1752 goto add_proto_failed;
1753 }
1754
1755 err = rtnl_link_register(&ipgre_link_ops);
1756 if (err < 0)
1757 goto rtnl_link_failed;
1758
1759 err = rtnl_link_register(&ipgre_tap_ops);
1760 if (err < 0)
1761 goto tap_ops_failed;
1762
1763 out:
1764 return err;
1765
1766 tap_ops_failed:
1767 rtnl_link_unregister(&ipgre_link_ops);
1768 rtnl_link_failed:
1769 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1770 add_proto_failed:
1771 unregister_pernet_device(&ipgre_net_ops);
1772 goto out;
1773 }
1774
1775 static void __exit ipgre_fini(void)
1776 {
1777 rtnl_link_unregister(&ipgre_tap_ops);
1778 rtnl_link_unregister(&ipgre_link_ops);
1779 if (gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0)
1780 pr_info("%s: can't remove protocol\n", __func__);
1781 unregister_pernet_device(&ipgre_net_ops);
1782 }
1783
1784 module_init(ipgre_init);
1785 module_exit(ipgre_fini);
1786 MODULE_LICENSE("GPL");
1787 MODULE_ALIAS_RTNL_LINK("gre");
1788 MODULE_ALIAS_RTNL_LINK("gretap");
1789 MODULE_ALIAS_NETDEV("gre0");
Linux kernel - Deliverables
This page took 0.093743 seconds and 4 git commands to generate.