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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/if_vlan.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/ip_tunnels.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#include <net/dst_metadata.h>
51
52#if IS_ENABLED(CONFIG_IPV6)
53#include <net/ipv6.h>
54#include <net/ip6_fib.h>
55#include <net/ip6_route.h>
56#endif
57
58/*
59 Problems & solutions
60 --------------------
61
62 1. The most important issue is detecting local dead loops.
63 They would cause complete host lockup in transmit, which
64 would be "resolved" by stack overflow or, if queueing is enabled,
65 with infinite looping in net_bh.
66
67 We cannot track such dead loops during route installation,
68 it is infeasible task. The most general solutions would be
69 to keep skb->encapsulation counter (sort of local ttl),
70 and silently drop packet when it expires. It is a good
71 solution, but it supposes maintaining new variable in ALL
72 skb, even if no tunneling is used.
73
74 Current solution: xmit_recursion breaks dead loops. This is a percpu
75 counter, since when we enter the first ndo_xmit(), cpu migration is
76 forbidden. We force an exit if this counter reaches RECURSION_LIMIT
77
78 2. Networking dead loops would not kill routers, but would really
79 kill network. IP hop limit plays role of "t->recursion" in this case,
80 if we copy it from packet being encapsulated to upper header.
81 It is very good solution, but it introduces two problems:
82
83 - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
84 do not work over tunnels.
85 - traceroute does not work. I planned to relay ICMP from tunnel,
86 so that this problem would be solved and traceroute output
87 would even more informative. This idea appeared to be wrong:
88 only Linux complies to rfc1812 now (yes, guys, Linux is the only
89 true router now :-)), all routers (at least, in neighbourhood of mine)
90 return only 8 bytes of payload. It is the end.
91
92 Hence, if we want that OSPF worked or traceroute said something reasonable,
93 we should search for another solution.
94
95 One of them is to parse packet trying to detect inner encapsulation
96 made by our node. It is difficult or even impossible, especially,
97 taking into account fragmentation. TO be short, ttl is not solution at all.
98
99 Current solution: The solution was UNEXPECTEDLY SIMPLE.
100 We force DF flag on tunnels with preconfigured hop limit,
101 that is ALL. :-) Well, it does not remove the problem completely,
102 but exponential growth of network traffic is changed to linear
103 (branches, that exceed pmtu are pruned) and tunnel mtu
104 rapidly degrades to value <68, where looping stops.
105 Yes, it is not good if there exists a router in the loop,
106 which does not force DF, even when encapsulating packets have DF set.
107 But it is not our problem! Nobody could accuse us, we made
108 all that we could make. Even if it is your gated who injected
109 fatal route to network, even if it were you who configured
110 fatal static route: you are innocent. :-)
111
112 Alexey Kuznetsov.
113 */
114
115static bool log_ecn_error = true;
116module_param(log_ecn_error, bool, 0644);
117MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
118
119static struct rtnl_link_ops ipgre_link_ops __read_mostly;
120static int ipgre_tunnel_init(struct net_device *dev);
121
122static int ipgre_net_id __read_mostly;
123static int gre_tap_net_id __read_mostly;
124
125static int ip_gre_calc_hlen(__be16 o_flags)
126{
127 int addend = 4;
128
129 if (o_flags & TUNNEL_CSUM)
130 addend += 4;
131 if (o_flags & TUNNEL_KEY)
132 addend += 4;
133 if (o_flags & TUNNEL_SEQ)
134 addend += 4;
135 return addend;
136}
137
138static __be16 gre_flags_to_tnl_flags(__be16 flags)
139{
140 __be16 tflags = 0;
141
142 if (flags & GRE_CSUM)
143 tflags |= TUNNEL_CSUM;
144 if (flags & GRE_ROUTING)
145 tflags |= TUNNEL_ROUTING;
146 if (flags & GRE_KEY)
147 tflags |= TUNNEL_KEY;
148 if (flags & GRE_SEQ)
149 tflags |= TUNNEL_SEQ;
150 if (flags & GRE_STRICT)
151 tflags |= TUNNEL_STRICT;
152 if (flags & GRE_REC)
153 tflags |= TUNNEL_REC;
154 if (flags & GRE_VERSION)
155 tflags |= TUNNEL_VERSION;
156
157 return tflags;
158}
159
160static __be16 tnl_flags_to_gre_flags(__be16 tflags)
161{
162 __be16 flags = 0;
163
164 if (tflags & TUNNEL_CSUM)
165 flags |= GRE_CSUM;
166 if (tflags & TUNNEL_ROUTING)
167 flags |= GRE_ROUTING;
168 if (tflags & TUNNEL_KEY)
169 flags |= GRE_KEY;
170 if (tflags & TUNNEL_SEQ)
171 flags |= GRE_SEQ;
172 if (tflags & TUNNEL_STRICT)
173 flags |= GRE_STRICT;
174 if (tflags & TUNNEL_REC)
175 flags |= GRE_REC;
176 if (tflags & TUNNEL_VERSION)
177 flags |= GRE_VERSION;
178
179 return flags;
180}
181
182/* Fills in tpi and returns header length to be pulled. */
183static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
184 bool *csum_err)
185{
186 const struct gre_base_hdr *greh;
187 __be32 *options;
188 int hdr_len;
189
190 if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
191 return -EINVAL;
192
193 greh = (struct gre_base_hdr *)skb_transport_header(skb);
194 if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
195 return -EINVAL;
196
197 tpi->flags = gre_flags_to_tnl_flags(greh->flags);
198 hdr_len = ip_gre_calc_hlen(tpi->flags);
199
200 if (!pskb_may_pull(skb, hdr_len))
201 return -EINVAL;
202
203 greh = (struct gre_base_hdr *)skb_transport_header(skb);
204 tpi->proto = greh->protocol;
205
206 options = (__be32 *)(greh + 1);
207 if (greh->flags & GRE_CSUM) {
208 if (skb_checksum_simple_validate(skb)) {
209 *csum_err = true;
210 return -EINVAL;
211 }
212
213 skb_checksum_try_convert(skb, IPPROTO_GRE, 0,
214 null_compute_pseudo);
215 options++;
216 }
217
218 if (greh->flags & GRE_KEY) {
219 tpi->key = *options;
220 options++;
221 } else {
222 tpi->key = 0;
223 }
224 if (unlikely(greh->flags & GRE_SEQ)) {
225 tpi->seq = *options;
226 options++;
227 } else {
228 tpi->seq = 0;
229 }
230 /* WCCP version 1 and 2 protocol decoding.
231 * - Change protocol to IP
232 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
233 */
234 if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
235 tpi->proto = htons(ETH_P_IP);
236 if ((*(u8 *)options & 0xF0) != 0x40) {
237 hdr_len += 4;
238 if (!pskb_may_pull(skb, hdr_len))
239 return -EINVAL;
240 }
241 }
242 return hdr_len;
243}
244
245static void ipgre_err(struct sk_buff *skb, u32 info,
246 const struct tnl_ptk_info *tpi)
247{
248
249 /* All the routers (except for Linux) return only
250 8 bytes of packet payload. It means, that precise relaying of
251 ICMP in the real Internet is absolutely infeasible.
252
253 Moreover, Cisco "wise men" put GRE key to the third word
254 in GRE header. It makes impossible maintaining even soft
255 state for keyed GRE tunnels with enabled checksum. Tell
256 them "thank you".
257
258 Well, I wonder, rfc1812 was written by Cisco employee,
259 what the hell these idiots break standards established
260 by themselves???
261 */
262 struct net *net = dev_net(skb->dev);
263 struct ip_tunnel_net *itn;
264 const struct iphdr *iph;
265 const int type = icmp_hdr(skb)->type;
266 const int code = icmp_hdr(skb)->code;
267 struct ip_tunnel *t;
268
269 switch (type) {
270 default:
271 case ICMP_PARAMETERPROB:
272 return;
273
274 case ICMP_DEST_UNREACH:
275 switch (code) {
276 case ICMP_SR_FAILED:
277 case ICMP_PORT_UNREACH:
278 /* Impossible event. */
279 return;
280 default:
281 /* All others are translated to HOST_UNREACH.
282 rfc2003 contains "deep thoughts" about NET_UNREACH,
283 I believe they are just ether pollution. --ANK
284 */
285 break;
286 }
287 break;
288
289 case ICMP_TIME_EXCEEDED:
290 if (code != ICMP_EXC_TTL)
291 return;
292 break;
293
294 case ICMP_REDIRECT:
295 break;
296 }
297
298 if (tpi->proto == htons(ETH_P_TEB))
299 itn = net_generic(net, gre_tap_net_id);
300 else
301 itn = net_generic(net, ipgre_net_id);
302
303 iph = (const struct iphdr *)(icmp_hdr(skb) + 1);
304 t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
305 iph->daddr, iph->saddr, tpi->key);
306
307 if (!t)
308 return;
309
310 if (t->parms.iph.daddr == 0 ||
311 ipv4_is_multicast(t->parms.iph.daddr))
312 return;
313
314 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
315 return;
316
317 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
318 t->err_count++;
319 else
320 t->err_count = 1;
321 t->err_time = jiffies;
322}
323
324static void gre_err(struct sk_buff *skb, u32 info)
325{
326 /* All the routers (except for Linux) return only
327 * 8 bytes of packet payload. It means, that precise relaying of
328 * ICMP in the real Internet is absolutely infeasible.
329 *
330 * Moreover, Cisco "wise men" put GRE key to the third word
331 * in GRE header. It makes impossible maintaining even soft
332 * state for keyed
333 * GRE tunnels with enabled checksum. Tell them "thank you".
334 *
335 * Well, I wonder, rfc1812 was written by Cisco employee,
336 * what the hell these idiots break standards established
337 * by themselves???
338 */
339
340 const int type = icmp_hdr(skb)->type;
341 const int code = icmp_hdr(skb)->code;
342 struct tnl_ptk_info tpi;
343 bool csum_err = false;
344
345 if (parse_gre_header(skb, &tpi, &csum_err) < 0) {
346 if (!csum_err) /* ignore csum errors. */
347 return;
348 }
349
350 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
351 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
352 skb->dev->ifindex, 0, IPPROTO_GRE, 0);
353 return;
354 }
355 if (type == ICMP_REDIRECT) {
356 ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0,
357 IPPROTO_GRE, 0);
358 return;
359 }
360
361 ipgre_err(skb, info, &tpi);
362}
363
364static __be64 key_to_tunnel_id(__be32 key)
365{
366#ifdef __BIG_ENDIAN
367 return (__force __be64)((__force u32)key);
368#else
369 return (__force __be64)((__force u64)key << 32);
370#endif
371}
372
373/* Returns the least-significant 32 bits of a __be64. */
374static __be32 tunnel_id_to_key(__be64 x)
375{
376#ifdef __BIG_ENDIAN
377 return (__force __be32)x;
378#else
379 return (__force __be32)((__force u64)x >> 32);
380#endif
381}
382
383static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
384{
385 struct net *net = dev_net(skb->dev);
386 struct metadata_dst *tun_dst = NULL;
387 struct ip_tunnel_net *itn;
388 const struct iphdr *iph;
389 struct ip_tunnel *tunnel;
390
391 if (tpi->proto == htons(ETH_P_TEB))
392 itn = net_generic(net, gre_tap_net_id);
393 else
394 itn = net_generic(net, ipgre_net_id);
395
396 iph = ip_hdr(skb);
397 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
398 iph->saddr, iph->daddr, tpi->key);
399
400 if (tunnel) {
401 if (tunnel->dev->type != ARPHRD_NONE)
402 skb_pop_mac_header(skb);
403 else
404 skb_reset_mac_header(skb);
405 if (tunnel->collect_md) {
406 __be16 flags;
407 __be64 tun_id;
408
409 flags = tpi->flags & (TUNNEL_CSUM | TUNNEL_KEY);
410 tun_id = key_to_tunnel_id(tpi->key);
411 tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0);
412 if (!tun_dst)
413 return PACKET_REJECT;
414 }
415
416 ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
417 return PACKET_RCVD;
418 }
419 return PACKET_REJECT;
420}
421
422static int gre_rcv(struct sk_buff *skb)
423{
424 struct tnl_ptk_info tpi;
425 bool csum_err = false;
426 int hdr_len;
427
428#ifdef CONFIG_NET_IPGRE_BROADCAST
429 if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
430 /* Looped back packet, drop it! */
431 if (rt_is_output_route(skb_rtable(skb)))
432 goto drop;
433 }
434#endif
435
436 hdr_len = parse_gre_header(skb, &tpi, &csum_err);
437 if (hdr_len < 0)
438 goto drop;
439 if (iptunnel_pull_header(skb, hdr_len, tpi.proto, false) < 0)
440 goto drop;
441
442 if (ipgre_rcv(skb, &tpi) == PACKET_RCVD)
443 return 0;
444
445 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
446drop:
447 kfree_skb(skb);
448 return 0;
449}
450
451static __sum16 gre_checksum(struct sk_buff *skb)
452{
453 __wsum csum;
454
455 if (skb->ip_summed == CHECKSUM_PARTIAL)
456 csum = lco_csum(skb);
457 else
458 csum = skb_checksum(skb, 0, skb->len, 0);
459 return csum_fold(csum);
460}
461
462static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,
463 __be16 proto, __be32 key, __be32 seq)
464{
465 struct gre_base_hdr *greh;
466
467 skb_push(skb, hdr_len);
468
469 skb_reset_transport_header(skb);
470 greh = (struct gre_base_hdr *)skb->data;
471 greh->flags = tnl_flags_to_gre_flags(flags);
472 greh->protocol = proto;
473
474 if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
475 __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);
476
477 if (flags & TUNNEL_SEQ) {
478 *ptr = seq;
479 ptr--;
480 }
481 if (flags & TUNNEL_KEY) {
482 *ptr = key;
483 ptr--;
484 }
485 if (flags & TUNNEL_CSUM &&
486 !(skb_shinfo(skb)->gso_type &
487 (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
488 *ptr = 0;
489 *(__sum16 *)ptr = gre_checksum(skb);
490 }
491 }
492}
493
494static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
495 const struct iphdr *tnl_params,
496 __be16 proto)
497{
498 struct ip_tunnel *tunnel = netdev_priv(dev);
499
500 if (tunnel->parms.o_flags & TUNNEL_SEQ)
501 tunnel->o_seqno++;
502
503 /* Push GRE header. */
504 build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,
505 proto, tunnel->parms.o_key, htonl(tunnel->o_seqno));
506
507 skb_set_inner_protocol(skb, proto);
508 ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
509}
510
511static struct sk_buff *gre_handle_offloads(struct sk_buff *skb,
512 bool csum)
513{
514 return iptunnel_handle_offloads(skb, csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
515}
516
517static struct rtable *gre_get_rt(struct sk_buff *skb,
518 struct net_device *dev,
519 struct flowi4 *fl,
520 const struct ip_tunnel_key *key)
521{
522 struct net *net = dev_net(dev);
523
524 memset(fl, 0, sizeof(*fl));
525 fl->daddr = key->u.ipv4.dst;
526 fl->saddr = key->u.ipv4.src;
527 fl->flowi4_tos = RT_TOS(key->tos);
528 fl->flowi4_mark = skb->mark;
529 fl->flowi4_proto = IPPROTO_GRE;
530
531 return ip_route_output_key(net, fl);
532}
533
534static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
535 __be16 proto)
536{
537 struct ip_tunnel_info *tun_info;
538 const struct ip_tunnel_key *key;
539 struct rtable *rt = NULL;
540 struct flowi4 fl;
541 int min_headroom;
542 int tunnel_hlen;
543 __be16 df, flags;
544 bool use_cache;
545 int err;
546
547 tun_info = skb_tunnel_info(skb);
548 if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
549 ip_tunnel_info_af(tun_info) != AF_INET))
550 goto err_free_skb;
551
552 key = &tun_info->key;
553 use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
554 if (use_cache)
555 rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl.saddr);
556 if (!rt) {
557 rt = gre_get_rt(skb, dev, &fl, key);
558 if (IS_ERR(rt))
559 goto err_free_skb;
560 if (use_cache)
561 dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
562 fl.saddr);
563 }
564
565 tunnel_hlen = ip_gre_calc_hlen(key->tun_flags);
566
567 min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
568 + tunnel_hlen + sizeof(struct iphdr);
569 if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
570 int head_delta = SKB_DATA_ALIGN(min_headroom -
571 skb_headroom(skb) +
572 16);
573 err = pskb_expand_head(skb, max_t(int, head_delta, 0),
574 0, GFP_ATOMIC);
575 if (unlikely(err))
576 goto err_free_rt;
577 }
578
579 /* Push Tunnel header. */
580 skb = gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM));
581 if (IS_ERR(skb)) {
582 skb = NULL;
583 goto err_free_rt;
584 }
585
586 flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
587 build_header(skb, tunnel_hlen, flags, proto,
588 tunnel_id_to_key(tun_info->key.tun_id), 0);
589
590 df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
591
592 iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE,
593 key->tos, key->ttl, df, false);
594 return;
595
596err_free_rt:
597 ip_rt_put(rt);
598err_free_skb:
599 kfree_skb(skb);
600 dev->stats.tx_dropped++;
601}
602
603static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
604{
605 struct ip_tunnel_info *info = skb_tunnel_info(skb);
606 struct rtable *rt;
607 struct flowi4 fl4;
608
609 if (ip_tunnel_info_af(info) != AF_INET)
610 return -EINVAL;
611
612 rt = gre_get_rt(skb, dev, &fl4, &info->key);
613 if (IS_ERR(rt))
614 return PTR_ERR(rt);
615
616 ip_rt_put(rt);
617 info->key.u.ipv4.src = fl4.saddr;
618 return 0;
619}
620
621static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
622 struct net_device *dev)
623{
624 struct ip_tunnel *tunnel = netdev_priv(dev);
625 const struct iphdr *tnl_params;
626
627 if (tunnel->collect_md) {
628 gre_fb_xmit(skb, dev, skb->protocol);
629 return NETDEV_TX_OK;
630 }
631
632 if (dev->header_ops) {
633 /* Need space for new headers */
634 if (skb_cow_head(skb, dev->needed_headroom -
635 (tunnel->hlen + sizeof(struct iphdr))))
636 goto free_skb;
637
638 tnl_params = (const struct iphdr *)skb->data;
639
640 /* Pull skb since ip_tunnel_xmit() needs skb->data pointing
641 * to gre header.
642 */
643 skb_pull(skb, tunnel->hlen + sizeof(struct iphdr));
644 skb_reset_mac_header(skb);
645 } else {
646 if (skb_cow_head(skb, dev->needed_headroom))
647 goto free_skb;
648
649 tnl_params = &tunnel->parms.iph;
650 }
651
652 skb = gre_handle_offloads(skb, !!(tunnel->parms.o_flags&TUNNEL_CSUM));
653 if (IS_ERR(skb))
654 goto out;
655
656 __gre_xmit(skb, dev, tnl_params, skb->protocol);
657 return NETDEV_TX_OK;
658
659free_skb:
660 kfree_skb(skb);
661out:
662 dev->stats.tx_dropped++;
663 return NETDEV_TX_OK;
664}
665
666static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
667 struct net_device *dev)
668{
669 struct ip_tunnel *tunnel = netdev_priv(dev);
670
671 if (tunnel->collect_md) {
672 gre_fb_xmit(skb, dev, htons(ETH_P_TEB));
673 return NETDEV_TX_OK;
674 }
675
676 skb = gre_handle_offloads(skb, !!(tunnel->parms.o_flags&TUNNEL_CSUM));
677 if (IS_ERR(skb))
678 goto out;
679
680 if (skb_cow_head(skb, dev->needed_headroom))
681 goto free_skb;
682
683 __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB));
684 return NETDEV_TX_OK;
685
686free_skb:
687 kfree_skb(skb);
688out:
689 dev->stats.tx_dropped++;
690 return NETDEV_TX_OK;
691}
692
693static int ipgre_tunnel_ioctl(struct net_device *dev,
694 struct ifreq *ifr, int cmd)
695{
696 int err;
697 struct ip_tunnel_parm p;
698
699 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
700 return -EFAULT;
701 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
702 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
703 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
704 ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
705 return -EINVAL;
706 }
707 p.i_flags = gre_flags_to_tnl_flags(p.i_flags);
708 p.o_flags = gre_flags_to_tnl_flags(p.o_flags);
709
710 err = ip_tunnel_ioctl(dev, &p, cmd);
711 if (err)
712 return err;
713
714 p.i_flags = tnl_flags_to_gre_flags(p.i_flags);
715 p.o_flags = tnl_flags_to_gre_flags(p.o_flags);
716
717 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
718 return -EFAULT;
719 return 0;
720}
721
722/* Nice toy. Unfortunately, useless in real life :-)
723 It allows to construct virtual multiprotocol broadcast "LAN"
724 over the Internet, provided multicast routing is tuned.
725
726
727 I have no idea was this bicycle invented before me,
728 so that I had to set ARPHRD_IPGRE to a random value.
729 I have an impression, that Cisco could make something similar,
730 but this feature is apparently missing in IOS<=11.2(8).
731
732 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
733 with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
734
735 ping -t 255 224.66.66.66
736
737 If nobody answers, mbone does not work.
738
739 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
740 ip addr add 10.66.66.<somewhat>/24 dev Universe
741 ifconfig Universe up
742 ifconfig Universe add fe80::<Your_real_addr>/10
743 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
744 ftp 10.66.66.66
745 ...
746 ftp fec0:6666:6666::193.233.7.65
747 ...
748 */
749static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
750 unsigned short type,
751 const void *daddr, const void *saddr, unsigned int len)
752{
753 struct ip_tunnel *t = netdev_priv(dev);
754 struct iphdr *iph;
755 struct gre_base_hdr *greh;
756
757 iph = (struct iphdr *)skb_push(skb, t->hlen + sizeof(*iph));
758 greh = (struct gre_base_hdr *)(iph+1);
759 greh->flags = tnl_flags_to_gre_flags(t->parms.o_flags);
760 greh->protocol = htons(type);
761
762 memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
763
764 /* Set the source hardware address. */
765 if (saddr)
766 memcpy(&iph->saddr, saddr, 4);
767 if (daddr)
768 memcpy(&iph->daddr, daddr, 4);
769 if (iph->daddr)
770 return t->hlen + sizeof(*iph);
771
772 return -(t->hlen + sizeof(*iph));
773}
774
775static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
776{
777 const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
778 memcpy(haddr, &iph->saddr, 4);
779 return 4;
780}
781
782static const struct header_ops ipgre_header_ops = {
783 .create = ipgre_header,
784 .parse = ipgre_header_parse,
785};
786
787#ifdef CONFIG_NET_IPGRE_BROADCAST
788static int ipgre_open(struct net_device *dev)
789{
790 struct ip_tunnel *t = netdev_priv(dev);
791
792 if (ipv4_is_multicast(t->parms.iph.daddr)) {
793 struct flowi4 fl4;
794 struct rtable *rt;
795
796 rt = ip_route_output_gre(t->net, &fl4,
797 t->parms.iph.daddr,
798 t->parms.iph.saddr,
799 t->parms.o_key,
800 RT_TOS(t->parms.iph.tos),
801 t->parms.link);
802 if (IS_ERR(rt))
803 return -EADDRNOTAVAIL;
804 dev = rt->dst.dev;
805 ip_rt_put(rt);
806 if (!__in_dev_get_rtnl(dev))
807 return -EADDRNOTAVAIL;
808 t->mlink = dev->ifindex;
809 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
810 }
811 return 0;
812}
813
814static int ipgre_close(struct net_device *dev)
815{
816 struct ip_tunnel *t = netdev_priv(dev);
817
818 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
819 struct in_device *in_dev;
820 in_dev = inetdev_by_index(t->net, t->mlink);
821 if (in_dev)
822 ip_mc_dec_group(in_dev, t->parms.iph.daddr);
823 }
824 return 0;
825}
826#endif
827
828static const struct net_device_ops ipgre_netdev_ops = {
829 .ndo_init = ipgre_tunnel_init,
830 .ndo_uninit = ip_tunnel_uninit,
831#ifdef CONFIG_NET_IPGRE_BROADCAST
832 .ndo_open = ipgre_open,
833 .ndo_stop = ipgre_close,
834#endif
835 .ndo_start_xmit = ipgre_xmit,
836 .ndo_do_ioctl = ipgre_tunnel_ioctl,
837 .ndo_change_mtu = ip_tunnel_change_mtu,
838 .ndo_get_stats64 = ip_tunnel_get_stats64,
839 .ndo_get_iflink = ip_tunnel_get_iflink,
840};
841
842#define GRE_FEATURES (NETIF_F_SG | \
843 NETIF_F_FRAGLIST | \
844 NETIF_F_HIGHDMA | \
845 NETIF_F_HW_CSUM)
846
847static void ipgre_tunnel_setup(struct net_device *dev)
848{
849 dev->netdev_ops = &ipgre_netdev_ops;
850 dev->type = ARPHRD_IPGRE;
851 ip_tunnel_setup(dev, ipgre_net_id);
852}
853
854static void __gre_tunnel_init(struct net_device *dev)
855{
856 struct ip_tunnel *tunnel;
857 int t_hlen;
858
859 tunnel = netdev_priv(dev);
860 tunnel->tun_hlen = ip_gre_calc_hlen(tunnel->parms.o_flags);
861 tunnel->parms.iph.protocol = IPPROTO_GRE;
862
863 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
864
865 t_hlen = tunnel->hlen + sizeof(struct iphdr);
866
867 dev->needed_headroom = LL_MAX_HEADER + t_hlen + 4;
868 dev->mtu = ETH_DATA_LEN - t_hlen - 4;
869
870 dev->features |= GRE_FEATURES;
871 dev->hw_features |= GRE_FEATURES;
872
873 if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
874 /* TCP offload with GRE SEQ is not supported, nor
875 * can we support 2 levels of outer headers requiring
876 * an update.
877 */
878 if (!(tunnel->parms.o_flags & TUNNEL_CSUM) ||
879 (tunnel->encap.type == TUNNEL_ENCAP_NONE)) {
880 dev->features |= NETIF_F_GSO_SOFTWARE;
881 dev->hw_features |= NETIF_F_GSO_SOFTWARE;
882 }
883
884 /* Can use a lockless transmit, unless we generate
885 * output sequences
886 */
887 dev->features |= NETIF_F_LLTX;
888 }
889}
890
891static int ipgre_tunnel_init(struct net_device *dev)
892{
893 struct ip_tunnel *tunnel = netdev_priv(dev);
894 struct iphdr *iph = &tunnel->parms.iph;
895
896 __gre_tunnel_init(dev);
897
898 memcpy(dev->dev_addr, &iph->saddr, 4);
899 memcpy(dev->broadcast, &iph->daddr, 4);
900
901 dev->flags = IFF_NOARP;
902 netif_keep_dst(dev);
903 dev->addr_len = 4;
904
905 if (iph->daddr && !tunnel->collect_md) {
906#ifdef CONFIG_NET_IPGRE_BROADCAST
907 if (ipv4_is_multicast(iph->daddr)) {
908 if (!iph->saddr)
909 return -EINVAL;
910 dev->flags = IFF_BROADCAST;
911 dev->header_ops = &ipgre_header_ops;
912 }
913#endif
914 } else if (!tunnel->collect_md) {
915 dev->header_ops = &ipgre_header_ops;
916 }
917
918 return ip_tunnel_init(dev);
919}
920
921static const struct gre_protocol ipgre_protocol = {
922 .handler = gre_rcv,
923 .err_handler = gre_err,
924};
925
926static int __net_init ipgre_init_net(struct net *net)
927{
928 return ip_tunnel_init_net(net, ipgre_net_id, &ipgre_link_ops, NULL);
929}
930
931static void __net_exit ipgre_exit_net(struct net *net)
932{
933 struct ip_tunnel_net *itn = net_generic(net, ipgre_net_id);
934 ip_tunnel_delete_net(itn, &ipgre_link_ops);
935}
936
937static struct pernet_operations ipgre_net_ops = {
938 .init = ipgre_init_net,
939 .exit = ipgre_exit_net,
940 .id = &ipgre_net_id,
941 .size = sizeof(struct ip_tunnel_net),
942};
943
944static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
945{
946 __be16 flags;
947
948 if (!data)
949 return 0;
950
951 flags = 0;
952 if (data[IFLA_GRE_IFLAGS])
953 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
954 if (data[IFLA_GRE_OFLAGS])
955 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
956 if (flags & (GRE_VERSION|GRE_ROUTING))
957 return -EINVAL;
958
959 if (data[IFLA_GRE_COLLECT_METADATA] &&
960 data[IFLA_GRE_ENCAP_TYPE] &&
961 nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE)
962 return -EINVAL;
963
964 return 0;
965}
966
967static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
968{
969 __be32 daddr;
970
971 if (tb[IFLA_ADDRESS]) {
972 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
973 return -EINVAL;
974 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
975 return -EADDRNOTAVAIL;
976 }
977
978 if (!data)
979 goto out;
980
981 if (data[IFLA_GRE_REMOTE]) {
982 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
983 if (!daddr)
984 return -EINVAL;
985 }
986
987out:
988 return ipgre_tunnel_validate(tb, data);
989}
990
991static void ipgre_netlink_parms(struct net_device *dev,
992 struct nlattr *data[],
993 struct nlattr *tb[],
994 struct ip_tunnel_parm *parms)
995{
996 memset(parms, 0, sizeof(*parms));
997
998 parms->iph.protocol = IPPROTO_GRE;
999
1000 if (!data)
1001 return;
1002
1003 if (data[IFLA_GRE_LINK])
1004 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1005
1006 if (data[IFLA_GRE_IFLAGS])
1007 parms->i_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_IFLAGS]));
1008
1009 if (data[IFLA_GRE_OFLAGS])
1010 parms->o_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_OFLAGS]));
1011
1012 if (data[IFLA_GRE_IKEY])
1013 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1014
1015 if (data[IFLA_GRE_OKEY])
1016 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1017
1018 if (data[IFLA_GRE_LOCAL])
1019 parms->iph.saddr = nla_get_in_addr(data[IFLA_GRE_LOCAL]);
1020
1021 if (data[IFLA_GRE_REMOTE])
1022 parms->iph.daddr = nla_get_in_addr(data[IFLA_GRE_REMOTE]);
1023
1024 if (data[IFLA_GRE_TTL])
1025 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1026
1027 if (data[IFLA_GRE_TOS])
1028 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1029
1030 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC]))
1031 parms->iph.frag_off = htons(IP_DF);
1032
1033 if (data[IFLA_GRE_COLLECT_METADATA]) {
1034 struct ip_tunnel *t = netdev_priv(dev);
1035
1036 t->collect_md = true;
1037 if (dev->type == ARPHRD_IPGRE)
1038 dev->type = ARPHRD_NONE;
1039 }
1040}
1041
1042/* This function returns true when ENCAP attributes are present in the nl msg */
1043static bool ipgre_netlink_encap_parms(struct nlattr *data[],
1044 struct ip_tunnel_encap *ipencap)
1045{
1046 bool ret = false;
1047
1048 memset(ipencap, 0, sizeof(*ipencap));
1049
1050 if (!data)
1051 return ret;
1052
1053 if (data[IFLA_GRE_ENCAP_TYPE]) {
1054 ret = true;
1055 ipencap->type = nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]);
1056 }
1057
1058 if (data[IFLA_GRE_ENCAP_FLAGS]) {
1059 ret = true;
1060 ipencap->flags = nla_get_u16(data[IFLA_GRE_ENCAP_FLAGS]);
1061 }
1062
1063 if (data[IFLA_GRE_ENCAP_SPORT]) {
1064 ret = true;
1065 ipencap->sport = nla_get_be16(data[IFLA_GRE_ENCAP_SPORT]);
1066 }
1067
1068 if (data[IFLA_GRE_ENCAP_DPORT]) {
1069 ret = true;
1070 ipencap->dport = nla_get_be16(data[IFLA_GRE_ENCAP_DPORT]);
1071 }
1072
1073 return ret;
1074}
1075
1076static int gre_tap_init(struct net_device *dev)
1077{
1078 __gre_tunnel_init(dev);
1079 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1080
1081 return ip_tunnel_init(dev);
1082}
1083
1084static const struct net_device_ops gre_tap_netdev_ops = {
1085 .ndo_init = gre_tap_init,
1086 .ndo_uninit = ip_tunnel_uninit,
1087 .ndo_start_xmit = gre_tap_xmit,
1088 .ndo_set_mac_address = eth_mac_addr,
1089 .ndo_validate_addr = eth_validate_addr,
1090 .ndo_change_mtu = ip_tunnel_change_mtu,
1091 .ndo_get_stats64 = ip_tunnel_get_stats64,
1092 .ndo_get_iflink = ip_tunnel_get_iflink,
1093 .ndo_fill_metadata_dst = gre_fill_metadata_dst,
1094};
1095
1096static void ipgre_tap_setup(struct net_device *dev)
1097{
1098 ether_setup(dev);
1099 dev->netdev_ops = &gre_tap_netdev_ops;
1100 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1101 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1102 ip_tunnel_setup(dev, gre_tap_net_id);
1103}
1104
1105static int ipgre_newlink(struct net *src_net, struct net_device *dev,
1106 struct nlattr *tb[], struct nlattr *data[])
1107{
1108 struct ip_tunnel_parm p;
1109 struct ip_tunnel_encap ipencap;
1110
1111 if (ipgre_netlink_encap_parms(data, &ipencap)) {
1112 struct ip_tunnel *t = netdev_priv(dev);
1113 int err = ip_tunnel_encap_setup(t, &ipencap);
1114
1115 if (err < 0)
1116 return err;
1117 }
1118
1119 ipgre_netlink_parms(dev, data, tb, &p);
1120 return ip_tunnel_newlink(dev, tb, &p);
1121}
1122
1123static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1124 struct nlattr *data[])
1125{
1126 struct ip_tunnel_parm p;
1127 struct ip_tunnel_encap ipencap;
1128
1129 if (ipgre_netlink_encap_parms(data, &ipencap)) {
1130 struct ip_tunnel *t = netdev_priv(dev);
1131 int err = ip_tunnel_encap_setup(t, &ipencap);
1132
1133 if (err < 0)
1134 return err;
1135 }
1136
1137 ipgre_netlink_parms(dev, data, tb, &p);
1138 return ip_tunnel_changelink(dev, tb, &p);
1139}
1140
1141static size_t ipgre_get_size(const struct net_device *dev)
1142{
1143 return
1144 /* IFLA_GRE_LINK */
1145 nla_total_size(4) +
1146 /* IFLA_GRE_IFLAGS */
1147 nla_total_size(2) +
1148 /* IFLA_GRE_OFLAGS */
1149 nla_total_size(2) +
1150 /* IFLA_GRE_IKEY */
1151 nla_total_size(4) +
1152 /* IFLA_GRE_OKEY */
1153 nla_total_size(4) +
1154 /* IFLA_GRE_LOCAL */
1155 nla_total_size(4) +
1156 /* IFLA_GRE_REMOTE */
1157 nla_total_size(4) +
1158 /* IFLA_GRE_TTL */
1159 nla_total_size(1) +
1160 /* IFLA_GRE_TOS */
1161 nla_total_size(1) +
1162 /* IFLA_GRE_PMTUDISC */
1163 nla_total_size(1) +
1164 /* IFLA_GRE_ENCAP_TYPE */
1165 nla_total_size(2) +
1166 /* IFLA_GRE_ENCAP_FLAGS */
1167 nla_total_size(2) +
1168 /* IFLA_GRE_ENCAP_SPORT */
1169 nla_total_size(2) +
1170 /* IFLA_GRE_ENCAP_DPORT */
1171 nla_total_size(2) +
1172 /* IFLA_GRE_COLLECT_METADATA */
1173 nla_total_size(0) +
1174 0;
1175}
1176
1177static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1178{
1179 struct ip_tunnel *t = netdev_priv(dev);
1180 struct ip_tunnel_parm *p = &t->parms;
1181
1182 if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
1183 nla_put_be16(skb, IFLA_GRE_IFLAGS, tnl_flags_to_gre_flags(p->i_flags)) ||
1184 nla_put_be16(skb, IFLA_GRE_OFLAGS, tnl_flags_to_gre_flags(p->o_flags)) ||
1185 nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
1186 nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
1187 nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
1188 nla_put_in_addr(skb, IFLA_GRE_REMOTE, p->iph.daddr) ||
1189 nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) ||
1190 nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) ||
1191 nla_put_u8(skb, IFLA_GRE_PMTUDISC,
1192 !!(p->iph.frag_off & htons(IP_DF))))
1193 goto nla_put_failure;
1194
1195 if (nla_put_u16(skb, IFLA_GRE_ENCAP_TYPE,
1196 t->encap.type) ||
1197 nla_put_be16(skb, IFLA_GRE_ENCAP_SPORT,
1198 t->encap.sport) ||
1199 nla_put_be16(skb, IFLA_GRE_ENCAP_DPORT,
1200 t->encap.dport) ||
1201 nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS,
1202 t->encap.flags))
1203 goto nla_put_failure;
1204
1205 if (t->collect_md) {
1206 if (nla_put_flag(skb, IFLA_GRE_COLLECT_METADATA))
1207 goto nla_put_failure;
1208 }
1209
1210 return 0;
1211
1212nla_put_failure:
1213 return -EMSGSIZE;
1214}
1215
1216static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1217 [IFLA_GRE_LINK] = { .type = NLA_U32 },
1218 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 },
1219 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 },
1220 [IFLA_GRE_IKEY] = { .type = NLA_U32 },
1221 [IFLA_GRE_OKEY] = { .type = NLA_U32 },
1222 [IFLA_GRE_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
1223 [IFLA_GRE_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
1224 [IFLA_GRE_TTL] = { .type = NLA_U8 },
1225 [IFLA_GRE_TOS] = { .type = NLA_U8 },
1226 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 },
1227 [IFLA_GRE_ENCAP_TYPE] = { .type = NLA_U16 },
1228 [IFLA_GRE_ENCAP_FLAGS] = { .type = NLA_U16 },
1229 [IFLA_GRE_ENCAP_SPORT] = { .type = NLA_U16 },
1230 [IFLA_GRE_ENCAP_DPORT] = { .type = NLA_U16 },
1231 [IFLA_GRE_COLLECT_METADATA] = { .type = NLA_FLAG },
1232};
1233
1234static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1235 .kind = "gre",
1236 .maxtype = IFLA_GRE_MAX,
1237 .policy = ipgre_policy,
1238 .priv_size = sizeof(struct ip_tunnel),
1239 .setup = ipgre_tunnel_setup,
1240 .validate = ipgre_tunnel_validate,
1241 .newlink = ipgre_newlink,
1242 .changelink = ipgre_changelink,
1243 .dellink = ip_tunnel_dellink,
1244 .get_size = ipgre_get_size,
1245 .fill_info = ipgre_fill_info,
1246 .get_link_net = ip_tunnel_get_link_net,
1247};
1248
1249static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1250 .kind = "gretap",
1251 .maxtype = IFLA_GRE_MAX,
1252 .policy = ipgre_policy,
1253 .priv_size = sizeof(struct ip_tunnel),
1254 .setup = ipgre_tap_setup,
1255 .validate = ipgre_tap_validate,
1256 .newlink = ipgre_newlink,
1257 .changelink = ipgre_changelink,
1258 .dellink = ip_tunnel_dellink,
1259 .get_size = ipgre_get_size,
1260 .fill_info = ipgre_fill_info,
1261 .get_link_net = ip_tunnel_get_link_net,
1262};
1263
1264struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
1265 u8 name_assign_type)
1266{
1267 struct nlattr *tb[IFLA_MAX + 1];
1268 struct net_device *dev;
1269 struct ip_tunnel *t;
1270 int err;
1271
1272 memset(&tb, 0, sizeof(tb));
1273
1274 dev = rtnl_create_link(net, name, name_assign_type,
1275 &ipgre_tap_ops, tb);
1276 if (IS_ERR(dev))
1277 return dev;
1278
1279 /* Configure flow based GRE device. */
1280 t = netdev_priv(dev);
1281 t->collect_md = true;
1282
1283 err = ipgre_newlink(net, dev, tb, NULL);
1284 if (err < 0)
1285 goto out;
1286
1287 /* openvswitch users expect packet sizes to be unrestricted,
1288 * so set the largest MTU we can.
1289 */
1290 err = __ip_tunnel_change_mtu(dev, IP_MAX_MTU, false);
1291 if (err)
1292 goto out;
1293
1294 return dev;
1295out:
1296 free_netdev(dev);
1297 return ERR_PTR(err);
1298}
1299EXPORT_SYMBOL_GPL(gretap_fb_dev_create);
1300
1301static int __net_init ipgre_tap_init_net(struct net *net)
1302{
1303 return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0");
1304}
1305
1306static void __net_exit ipgre_tap_exit_net(struct net *net)
1307{
1308 struct ip_tunnel_net *itn = net_generic(net, gre_tap_net_id);
1309 ip_tunnel_delete_net(itn, &ipgre_tap_ops);
1310}
1311
1312static struct pernet_operations ipgre_tap_net_ops = {
1313 .init = ipgre_tap_init_net,
1314 .exit = ipgre_tap_exit_net,
1315 .id = &gre_tap_net_id,
1316 .size = sizeof(struct ip_tunnel_net),
1317};
1318
1319static int __init ipgre_init(void)
1320{
1321 int err;
1322
1323 pr_info("GRE over IPv4 tunneling driver\n");
1324
1325 err = register_pernet_device(&ipgre_net_ops);
1326 if (err < 0)
1327 return err;
1328
1329 err = register_pernet_device(&ipgre_tap_net_ops);
1330 if (err < 0)
1331 goto pnet_tap_faied;
1332
1333 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
1334 if (err < 0) {
1335 pr_info("%s: can't add protocol\n", __func__);
1336 goto add_proto_failed;
1337 }
1338
1339 err = rtnl_link_register(&ipgre_link_ops);
1340 if (err < 0)
1341 goto rtnl_link_failed;
1342
1343 err = rtnl_link_register(&ipgre_tap_ops);
1344 if (err < 0)
1345 goto tap_ops_failed;
1346
1347 return 0;
1348
1349tap_ops_failed:
1350 rtnl_link_unregister(&ipgre_link_ops);
1351rtnl_link_failed:
1352 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1353add_proto_failed:
1354 unregister_pernet_device(&ipgre_tap_net_ops);
1355pnet_tap_faied:
1356 unregister_pernet_device(&ipgre_net_ops);
1357 return err;
1358}
1359
1360static void __exit ipgre_fini(void)
1361{
1362 rtnl_link_unregister(&ipgre_tap_ops);
1363 rtnl_link_unregister(&ipgre_link_ops);
1364 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1365 unregister_pernet_device(&ipgre_tap_net_ops);
1366 unregister_pernet_device(&ipgre_net_ops);
1367}
1368
1369module_init(ipgre_init);
1370module_exit(ipgre_fini);
1371MODULE_LICENSE("GPL");
1372MODULE_ALIAS_RTNL_LINK("gre");
1373MODULE_ALIAS_RTNL_LINK("gretap");
1374MODULE_ALIAS_NETDEV("gre0");
1375MODULE_ALIAS_NETDEV("gretap0");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Linux NET3: GRE over IP protocol decoder.
4 *
5 * Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru)
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/capability.h>
11#include <linux/module.h>
12#include <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/slab.h>
15#include <linux/uaccess.h>
16#include <linux/skbuff.h>
17#include <linux/netdevice.h>
18#include <linux/in.h>
19#include <linux/tcp.h>
20#include <linux/udp.h>
21#include <linux/if_arp.h>
22#include <linux/if_vlan.h>
23#include <linux/init.h>
24#include <linux/in6.h>
25#include <linux/inetdevice.h>
26#include <linux/igmp.h>
27#include <linux/netfilter_ipv4.h>
28#include <linux/etherdevice.h>
29#include <linux/if_ether.h>
30
31#include <net/sock.h>
32#include <net/ip.h>
33#include <net/icmp.h>
34#include <net/protocol.h>
35#include <net/ip_tunnels.h>
36#include <net/arp.h>
37#include <net/checksum.h>
38#include <net/dsfield.h>
39#include <net/inet_ecn.h>
40#include <net/xfrm.h>
41#include <net/net_namespace.h>
42#include <net/netns/generic.h>
43#include <net/rtnetlink.h>
44#include <net/gre.h>
45#include <net/dst_metadata.h>
46#include <net/erspan.h>
47
48/*
49 Problems & solutions
50 --------------------
51
52 1. The most important issue is detecting local dead loops.
53 They would cause complete host lockup in transmit, which
54 would be "resolved" by stack overflow or, if queueing is enabled,
55 with infinite looping in net_bh.
56
57 We cannot track such dead loops during route installation,
58 it is infeasible task. The most general solutions would be
59 to keep skb->encapsulation counter (sort of local ttl),
60 and silently drop packet when it expires. It is a good
61 solution, but it supposes maintaining new variable in ALL
62 skb, even if no tunneling is used.
63
64 Current solution: xmit_recursion breaks dead loops. This is a percpu
65 counter, since when we enter the first ndo_xmit(), cpu migration is
66 forbidden. We force an exit if this counter reaches RECURSION_LIMIT
67
68 2. Networking dead loops would not kill routers, but would really
69 kill network. IP hop limit plays role of "t->recursion" in this case,
70 if we copy it from packet being encapsulated to upper header.
71 It is very good solution, but it introduces two problems:
72
73 - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
74 do not work over tunnels.
75 - traceroute does not work. I planned to relay ICMP from tunnel,
76 so that this problem would be solved and traceroute output
77 would even more informative. This idea appeared to be wrong:
78 only Linux complies to rfc1812 now (yes, guys, Linux is the only
79 true router now :-)), all routers (at least, in neighbourhood of mine)
80 return only 8 bytes of payload. It is the end.
81
82 Hence, if we want that OSPF worked or traceroute said something reasonable,
83 we should search for another solution.
84
85 One of them is to parse packet trying to detect inner encapsulation
86 made by our node. It is difficult or even impossible, especially,
87 taking into account fragmentation. TO be short, ttl is not solution at all.
88
89 Current solution: The solution was UNEXPECTEDLY SIMPLE.
90 We force DF flag on tunnels with preconfigured hop limit,
91 that is ALL. :-) Well, it does not remove the problem completely,
92 but exponential growth of network traffic is changed to linear
93 (branches, that exceed pmtu are pruned) and tunnel mtu
94 rapidly degrades to value <68, where looping stops.
95 Yes, it is not good if there exists a router in the loop,
96 which does not force DF, even when encapsulating packets have DF set.
97 But it is not our problem! Nobody could accuse us, we made
98 all that we could make. Even if it is your gated who injected
99 fatal route to network, even if it were you who configured
100 fatal static route: you are innocent. :-)
101
102 Alexey Kuznetsov.
103 */
104
105static bool log_ecn_error = true;
106module_param(log_ecn_error, bool, 0644);
107MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
108
109static struct rtnl_link_ops ipgre_link_ops __read_mostly;
110static const struct header_ops ipgre_header_ops;
111
112static int ipgre_tunnel_init(struct net_device *dev);
113static void erspan_build_header(struct sk_buff *skb,
114 u32 id, u32 index,
115 bool truncate, bool is_ipv4);
116
117static unsigned int ipgre_net_id __read_mostly;
118static unsigned int gre_tap_net_id __read_mostly;
119static unsigned int erspan_net_id __read_mostly;
120
121static int ipgre_err(struct sk_buff *skb, u32 info,
122 const struct tnl_ptk_info *tpi)
123{
124
125 /* All the routers (except for Linux) return only
126 8 bytes of packet payload. It means, that precise relaying of
127 ICMP in the real Internet is absolutely infeasible.
128
129 Moreover, Cisco "wise men" put GRE key to the third word
130 in GRE header. It makes impossible maintaining even soft
131 state for keyed GRE tunnels with enabled checksum. Tell
132 them "thank you".
133
134 Well, I wonder, rfc1812 was written by Cisco employee,
135 what the hell these idiots break standards established
136 by themselves???
137 */
138 struct net *net = dev_net(skb->dev);
139 struct ip_tunnel_net *itn;
140 const struct iphdr *iph;
141 const int type = icmp_hdr(skb)->type;
142 const int code = icmp_hdr(skb)->code;
143 unsigned int data_len = 0;
144 struct ip_tunnel *t;
145
146 if (tpi->proto == htons(ETH_P_TEB))
147 itn = net_generic(net, gre_tap_net_id);
148 else if (tpi->proto == htons(ETH_P_ERSPAN) ||
149 tpi->proto == htons(ETH_P_ERSPAN2))
150 itn = net_generic(net, erspan_net_id);
151 else
152 itn = net_generic(net, ipgre_net_id);
153
154 iph = (const struct iphdr *)(icmp_hdr(skb) + 1);
155 t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
156 iph->daddr, iph->saddr, tpi->key);
157
158 if (!t)
159 return -ENOENT;
160
161 switch (type) {
162 default:
163 case ICMP_PARAMETERPROB:
164 return 0;
165
166 case ICMP_DEST_UNREACH:
167 switch (code) {
168 case ICMP_SR_FAILED:
169 case ICMP_PORT_UNREACH:
170 /* Impossible event. */
171 return 0;
172 default:
173 /* All others are translated to HOST_UNREACH.
174 rfc2003 contains "deep thoughts" about NET_UNREACH,
175 I believe they are just ether pollution. --ANK
176 */
177 break;
178 }
179 break;
180
181 case ICMP_TIME_EXCEEDED:
182 if (code != ICMP_EXC_TTL)
183 return 0;
184 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
185 break;
186
187 case ICMP_REDIRECT:
188 break;
189 }
190
191#if IS_ENABLED(CONFIG_IPV6)
192 if (tpi->proto == htons(ETH_P_IPV6) &&
193 !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len,
194 type, data_len))
195 return 0;
196#endif
197
198 if (t->parms.iph.daddr == 0 ||
199 ipv4_is_multicast(t->parms.iph.daddr))
200 return 0;
201
202 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
203 return 0;
204
205 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
206 t->err_count++;
207 else
208 t->err_count = 1;
209 t->err_time = jiffies;
210
211 return 0;
212}
213
214static void gre_err(struct sk_buff *skb, u32 info)
215{
216 /* All the routers (except for Linux) return only
217 * 8 bytes of packet payload. It means, that precise relaying of
218 * ICMP in the real Internet is absolutely infeasible.
219 *
220 * Moreover, Cisco "wise men" put GRE key to the third word
221 * in GRE header. It makes impossible maintaining even soft
222 * state for keyed
223 * GRE tunnels with enabled checksum. Tell them "thank you".
224 *
225 * Well, I wonder, rfc1812 was written by Cisco employee,
226 * what the hell these idiots break standards established
227 * by themselves???
228 */
229
230 const struct iphdr *iph = (struct iphdr *)skb->data;
231 const int type = icmp_hdr(skb)->type;
232 const int code = icmp_hdr(skb)->code;
233 struct tnl_ptk_info tpi;
234
235 if (gre_parse_header(skb, &tpi, NULL, htons(ETH_P_IP),
236 iph->ihl * 4) < 0)
237 return;
238
239 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
240 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
241 skb->dev->ifindex, IPPROTO_GRE);
242 return;
243 }
244 if (type == ICMP_REDIRECT) {
245 ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex,
246 IPPROTO_GRE);
247 return;
248 }
249
250 ipgre_err(skb, info, &tpi);
251}
252
253static bool is_erspan_type1(int gre_hdr_len)
254{
255 /* Both ERSPAN type I (version 0) and type II (version 1) use
256 * protocol 0x88BE, but the type I has only 4-byte GRE header,
257 * while type II has 8-byte.
258 */
259 return gre_hdr_len == 4;
260}
261
262static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
263 int gre_hdr_len)
264{
265 struct net *net = dev_net(skb->dev);
266 struct metadata_dst *tun_dst = NULL;
267 struct erspan_base_hdr *ershdr;
268 struct ip_tunnel_net *itn;
269 struct ip_tunnel *tunnel;
270 const struct iphdr *iph;
271 struct erspan_md2 *md2;
272 int ver;
273 int len;
274
275 itn = net_generic(net, erspan_net_id);
276 iph = ip_hdr(skb);
277 if (is_erspan_type1(gre_hdr_len)) {
278 ver = 0;
279 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
280 tpi->flags | TUNNEL_NO_KEY,
281 iph->saddr, iph->daddr, 0);
282 } else {
283 if (unlikely(!pskb_may_pull(skb,
284 gre_hdr_len + sizeof(*ershdr))))
285 return PACKET_REJECT;
286
287 ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
288 ver = ershdr->ver;
289 iph = ip_hdr(skb);
290 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
291 tpi->flags | TUNNEL_KEY,
292 iph->saddr, iph->daddr, tpi->key);
293 }
294
295 if (tunnel) {
296 if (is_erspan_type1(gre_hdr_len))
297 len = gre_hdr_len;
298 else
299 len = gre_hdr_len + erspan_hdr_len(ver);
300
301 if (unlikely(!pskb_may_pull(skb, len)))
302 return PACKET_REJECT;
303
304 if (__iptunnel_pull_header(skb,
305 len,
306 htons(ETH_P_TEB),
307 false, false) < 0)
308 goto drop;
309
310 if (tunnel->collect_md) {
311 struct erspan_metadata *pkt_md, *md;
312 struct ip_tunnel_info *info;
313 unsigned char *gh;
314 __be64 tun_id;
315 __be16 flags;
316
317 tpi->flags |= TUNNEL_KEY;
318 flags = tpi->flags;
319 tun_id = key32_to_tunnel_id(tpi->key);
320
321 tun_dst = ip_tun_rx_dst(skb, flags,
322 tun_id, sizeof(*md));
323 if (!tun_dst)
324 return PACKET_REJECT;
325
326 /* skb can be uncloned in __iptunnel_pull_header, so
327 * old pkt_md is no longer valid and we need to reset
328 * it
329 */
330 gh = skb_network_header(skb) +
331 skb_network_header_len(skb);
332 pkt_md = (struct erspan_metadata *)(gh + gre_hdr_len +
333 sizeof(*ershdr));
334 md = ip_tunnel_info_opts(&tun_dst->u.tun_info);
335 md->version = ver;
336 md2 = &md->u.md2;
337 memcpy(md2, pkt_md, ver == 1 ? ERSPAN_V1_MDSIZE :
338 ERSPAN_V2_MDSIZE);
339
340 info = &tun_dst->u.tun_info;
341 info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
342 info->options_len = sizeof(*md);
343 }
344
345 skb_reset_mac_header(skb);
346 ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
347 return PACKET_RCVD;
348 }
349 return PACKET_REJECT;
350
351drop:
352 kfree_skb(skb);
353 return PACKET_RCVD;
354}
355
356static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
357 struct ip_tunnel_net *itn, int hdr_len, bool raw_proto)
358{
359 struct metadata_dst *tun_dst = NULL;
360 const struct iphdr *iph;
361 struct ip_tunnel *tunnel;
362
363 iph = ip_hdr(skb);
364 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
365 iph->saddr, iph->daddr, tpi->key);
366
367 if (tunnel) {
368 const struct iphdr *tnl_params;
369
370 if (__iptunnel_pull_header(skb, hdr_len, tpi->proto,
371 raw_proto, false) < 0)
372 goto drop;
373
374 /* Special case for ipgre_header_parse(), which expects the
375 * mac_header to point to the outer IP header.
376 */
377 if (tunnel->dev->header_ops == &ipgre_header_ops)
378 skb_pop_mac_header(skb);
379 else
380 skb_reset_mac_header(skb);
381
382 tnl_params = &tunnel->parms.iph;
383 if (tunnel->collect_md || tnl_params->daddr == 0) {
384 __be16 flags;
385 __be64 tun_id;
386
387 flags = tpi->flags & (TUNNEL_CSUM | TUNNEL_KEY);
388 tun_id = key32_to_tunnel_id(tpi->key);
389 tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0);
390 if (!tun_dst)
391 return PACKET_REJECT;
392 }
393
394 ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
395 return PACKET_RCVD;
396 }
397 return PACKET_NEXT;
398
399drop:
400 kfree_skb(skb);
401 return PACKET_RCVD;
402}
403
404static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
405 int hdr_len)
406{
407 struct net *net = dev_net(skb->dev);
408 struct ip_tunnel_net *itn;
409 int res;
410
411 if (tpi->proto == htons(ETH_P_TEB))
412 itn = net_generic(net, gre_tap_net_id);
413 else
414 itn = net_generic(net, ipgre_net_id);
415
416 res = __ipgre_rcv(skb, tpi, itn, hdr_len, false);
417 if (res == PACKET_NEXT && tpi->proto == htons(ETH_P_TEB)) {
418 /* ipgre tunnels in collect metadata mode should receive
419 * also ETH_P_TEB traffic.
420 */
421 itn = net_generic(net, ipgre_net_id);
422 res = __ipgre_rcv(skb, tpi, itn, hdr_len, true);
423 }
424 return res;
425}
426
427static int gre_rcv(struct sk_buff *skb)
428{
429 struct tnl_ptk_info tpi;
430 bool csum_err = false;
431 int hdr_len;
432
433#ifdef CONFIG_NET_IPGRE_BROADCAST
434 if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
435 /* Looped back packet, drop it! */
436 if (rt_is_output_route(skb_rtable(skb)))
437 goto drop;
438 }
439#endif
440
441 hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP), 0);
442 if (hdr_len < 0)
443 goto drop;
444
445 if (unlikely(tpi.proto == htons(ETH_P_ERSPAN) ||
446 tpi.proto == htons(ETH_P_ERSPAN2))) {
447 if (erspan_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
448 return 0;
449 goto out;
450 }
451
452 if (ipgre_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
453 return 0;
454
455out:
456 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
457drop:
458 kfree_skb(skb);
459 return 0;
460}
461
462static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
463 const struct iphdr *tnl_params,
464 __be16 proto)
465{
466 struct ip_tunnel *tunnel = netdev_priv(dev);
467 __be16 flags = tunnel->parms.o_flags;
468
469 /* Push GRE header. */
470 gre_build_header(skb, tunnel->tun_hlen,
471 flags, proto, tunnel->parms.o_key,
472 (flags & TUNNEL_SEQ) ? htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0);
473
474 ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
475}
476
477static int gre_handle_offloads(struct sk_buff *skb, bool csum)
478{
479 return iptunnel_handle_offloads(skb, csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
480}
481
482static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
483 __be16 proto)
484{
485 struct ip_tunnel *tunnel = netdev_priv(dev);
486 struct ip_tunnel_info *tun_info;
487 const struct ip_tunnel_key *key;
488 int tunnel_hlen;
489 __be16 flags;
490
491 tun_info = skb_tunnel_info(skb);
492 if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
493 ip_tunnel_info_af(tun_info) != AF_INET))
494 goto err_free_skb;
495
496 key = &tun_info->key;
497 tunnel_hlen = gre_calc_hlen(key->tun_flags);
498
499 if (skb_cow_head(skb, dev->needed_headroom))
500 goto err_free_skb;
501
502 /* Push Tunnel header. */
503 if (gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM)))
504 goto err_free_skb;
505
506 flags = tun_info->key.tun_flags &
507 (TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
508 gre_build_header(skb, tunnel_hlen, flags, proto,
509 tunnel_id_to_key32(tun_info->key.tun_id),
510 (flags & TUNNEL_SEQ) ? htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0);
511
512 ip_md_tunnel_xmit(skb, dev, IPPROTO_GRE, tunnel_hlen);
513
514 return;
515
516err_free_skb:
517 kfree_skb(skb);
518 DEV_STATS_INC(dev, tx_dropped);
519}
520
521static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev)
522{
523 struct ip_tunnel *tunnel = netdev_priv(dev);
524 struct ip_tunnel_info *tun_info;
525 const struct ip_tunnel_key *key;
526 struct erspan_metadata *md;
527 bool truncate = false;
528 __be16 proto;
529 int tunnel_hlen;
530 int version;
531 int nhoff;
532
533 tun_info = skb_tunnel_info(skb);
534 if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
535 ip_tunnel_info_af(tun_info) != AF_INET))
536 goto err_free_skb;
537
538 key = &tun_info->key;
539 if (!(tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT))
540 goto err_free_skb;
541 if (tun_info->options_len < sizeof(*md))
542 goto err_free_skb;
543 md = ip_tunnel_info_opts(tun_info);
544
545 /* ERSPAN has fixed 8 byte GRE header */
546 version = md->version;
547 tunnel_hlen = 8 + erspan_hdr_len(version);
548
549 if (skb_cow_head(skb, dev->needed_headroom))
550 goto err_free_skb;
551
552 if (gre_handle_offloads(skb, false))
553 goto err_free_skb;
554
555 if (skb->len > dev->mtu + dev->hard_header_len) {
556 if (pskb_trim(skb, dev->mtu + dev->hard_header_len))
557 goto err_free_skb;
558 truncate = true;
559 }
560
561 nhoff = skb_network_offset(skb);
562 if (skb->protocol == htons(ETH_P_IP) &&
563 (ntohs(ip_hdr(skb)->tot_len) > skb->len - nhoff))
564 truncate = true;
565
566 if (skb->protocol == htons(ETH_P_IPV6)) {
567 int thoff;
568
569 if (skb_transport_header_was_set(skb))
570 thoff = skb_transport_offset(skb);
571 else
572 thoff = nhoff + sizeof(struct ipv6hdr);
573 if (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff)
574 truncate = true;
575 }
576
577 if (version == 1) {
578 erspan_build_header(skb, ntohl(tunnel_id_to_key32(key->tun_id)),
579 ntohl(md->u.index), truncate, true);
580 proto = htons(ETH_P_ERSPAN);
581 } else if (version == 2) {
582 erspan_build_header_v2(skb,
583 ntohl(tunnel_id_to_key32(key->tun_id)),
584 md->u.md2.dir,
585 get_hwid(&md->u.md2),
586 truncate, true);
587 proto = htons(ETH_P_ERSPAN2);
588 } else {
589 goto err_free_skb;
590 }
591
592 gre_build_header(skb, 8, TUNNEL_SEQ,
593 proto, 0, htonl(atomic_fetch_inc(&tunnel->o_seqno)));
594
595 ip_md_tunnel_xmit(skb, dev, IPPROTO_GRE, tunnel_hlen);
596
597 return;
598
599err_free_skb:
600 kfree_skb(skb);
601 DEV_STATS_INC(dev, tx_dropped);
602}
603
604static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
605{
606 struct ip_tunnel_info *info = skb_tunnel_info(skb);
607 const struct ip_tunnel_key *key;
608 struct rtable *rt;
609 struct flowi4 fl4;
610
611 if (ip_tunnel_info_af(info) != AF_INET)
612 return -EINVAL;
613
614 key = &info->key;
615 ip_tunnel_init_flow(&fl4, IPPROTO_GRE, key->u.ipv4.dst, key->u.ipv4.src,
616 tunnel_id_to_key32(key->tun_id),
617 key->tos & ~INET_ECN_MASK, dev_net(dev), 0,
618 skb->mark, skb_get_hash(skb), key->flow_flags);
619 rt = ip_route_output_key(dev_net(dev), &fl4);
620 if (IS_ERR(rt))
621 return PTR_ERR(rt);
622
623 ip_rt_put(rt);
624 info->key.u.ipv4.src = fl4.saddr;
625 return 0;
626}
627
628static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
629 struct net_device *dev)
630{
631 struct ip_tunnel *tunnel = netdev_priv(dev);
632 const struct iphdr *tnl_params;
633
634 if (!pskb_inet_may_pull(skb))
635 goto free_skb;
636
637 if (tunnel->collect_md) {
638 gre_fb_xmit(skb, dev, skb->protocol);
639 return NETDEV_TX_OK;
640 }
641
642 if (dev->header_ops) {
643 int pull_len = tunnel->hlen + sizeof(struct iphdr);
644
645 if (skb_cow_head(skb, 0))
646 goto free_skb;
647
648 tnl_params = (const struct iphdr *)skb->data;
649
650 if (!pskb_network_may_pull(skb, pull_len))
651 goto free_skb;
652
653 /* ip_tunnel_xmit() needs skb->data pointing to gre header. */
654 skb_pull(skb, pull_len);
655 skb_reset_mac_header(skb);
656
657 if (skb->ip_summed == CHECKSUM_PARTIAL &&
658 skb_checksum_start(skb) < skb->data)
659 goto free_skb;
660 } else {
661 if (skb_cow_head(skb, dev->needed_headroom))
662 goto free_skb;
663
664 tnl_params = &tunnel->parms.iph;
665 }
666
667 if (gre_handle_offloads(skb, !!(tunnel->parms.o_flags & TUNNEL_CSUM)))
668 goto free_skb;
669
670 __gre_xmit(skb, dev, tnl_params, skb->protocol);
671 return NETDEV_TX_OK;
672
673free_skb:
674 kfree_skb(skb);
675 DEV_STATS_INC(dev, tx_dropped);
676 return NETDEV_TX_OK;
677}
678
679static netdev_tx_t erspan_xmit(struct sk_buff *skb,
680 struct net_device *dev)
681{
682 struct ip_tunnel *tunnel = netdev_priv(dev);
683 bool truncate = false;
684 __be16 proto;
685
686 if (!pskb_inet_may_pull(skb))
687 goto free_skb;
688
689 if (tunnel->collect_md) {
690 erspan_fb_xmit(skb, dev);
691 return NETDEV_TX_OK;
692 }
693
694 if (gre_handle_offloads(skb, false))
695 goto free_skb;
696
697 if (skb_cow_head(skb, dev->needed_headroom))
698 goto free_skb;
699
700 if (skb->len > dev->mtu + dev->hard_header_len) {
701 if (pskb_trim(skb, dev->mtu + dev->hard_header_len))
702 goto free_skb;
703 truncate = true;
704 }
705
706 /* Push ERSPAN header */
707 if (tunnel->erspan_ver == 0) {
708 proto = htons(ETH_P_ERSPAN);
709 tunnel->parms.o_flags &= ~TUNNEL_SEQ;
710 } else if (tunnel->erspan_ver == 1) {
711 erspan_build_header(skb, ntohl(tunnel->parms.o_key),
712 tunnel->index,
713 truncate, true);
714 proto = htons(ETH_P_ERSPAN);
715 } else if (tunnel->erspan_ver == 2) {
716 erspan_build_header_v2(skb, ntohl(tunnel->parms.o_key),
717 tunnel->dir, tunnel->hwid,
718 truncate, true);
719 proto = htons(ETH_P_ERSPAN2);
720 } else {
721 goto free_skb;
722 }
723
724 tunnel->parms.o_flags &= ~TUNNEL_KEY;
725 __gre_xmit(skb, dev, &tunnel->parms.iph, proto);
726 return NETDEV_TX_OK;
727
728free_skb:
729 kfree_skb(skb);
730 DEV_STATS_INC(dev, tx_dropped);
731 return NETDEV_TX_OK;
732}
733
734static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
735 struct net_device *dev)
736{
737 struct ip_tunnel *tunnel = netdev_priv(dev);
738
739 if (!pskb_inet_may_pull(skb))
740 goto free_skb;
741
742 if (tunnel->collect_md) {
743 gre_fb_xmit(skb, dev, htons(ETH_P_TEB));
744 return NETDEV_TX_OK;
745 }
746
747 if (gre_handle_offloads(skb, !!(tunnel->parms.o_flags & TUNNEL_CSUM)))
748 goto free_skb;
749
750 if (skb_cow_head(skb, dev->needed_headroom))
751 goto free_skb;
752
753 __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB));
754 return NETDEV_TX_OK;
755
756free_skb:
757 kfree_skb(skb);
758 DEV_STATS_INC(dev, tx_dropped);
759 return NETDEV_TX_OK;
760}
761
762static void ipgre_link_update(struct net_device *dev, bool set_mtu)
763{
764 struct ip_tunnel *tunnel = netdev_priv(dev);
765 __be16 flags;
766 int len;
767
768 len = tunnel->tun_hlen;
769 tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
770 len = tunnel->tun_hlen - len;
771 tunnel->hlen = tunnel->hlen + len;
772
773 if (dev->header_ops)
774 dev->hard_header_len += len;
775 else
776 dev->needed_headroom += len;
777
778 if (set_mtu)
779 dev->mtu = max_t(int, dev->mtu - len, 68);
780
781 flags = tunnel->parms.o_flags;
782
783 if (flags & TUNNEL_SEQ ||
784 (flags & TUNNEL_CSUM && tunnel->encap.type != TUNNEL_ENCAP_NONE)) {
785 dev->features &= ~NETIF_F_GSO_SOFTWARE;
786 dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
787 } else {
788 dev->features |= NETIF_F_GSO_SOFTWARE;
789 dev->hw_features |= NETIF_F_GSO_SOFTWARE;
790 }
791}
792
793static int ipgre_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm *p,
794 int cmd)
795{
796 int err;
797
798 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
799 if (p->iph.version != 4 || p->iph.protocol != IPPROTO_GRE ||
800 p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)) ||
801 ((p->i_flags | p->o_flags) & (GRE_VERSION | GRE_ROUTING)))
802 return -EINVAL;
803 }
804
805 p->i_flags = gre_flags_to_tnl_flags(p->i_flags);
806 p->o_flags = gre_flags_to_tnl_flags(p->o_flags);
807
808 err = ip_tunnel_ctl(dev, p, cmd);
809 if (err)
810 return err;
811
812 if (cmd == SIOCCHGTUNNEL) {
813 struct ip_tunnel *t = netdev_priv(dev);
814
815 t->parms.i_flags = p->i_flags;
816 t->parms.o_flags = p->o_flags;
817
818 if (strcmp(dev->rtnl_link_ops->kind, "erspan"))
819 ipgre_link_update(dev, true);
820 }
821
822 p->i_flags = gre_tnl_flags_to_gre_flags(p->i_flags);
823 p->o_flags = gre_tnl_flags_to_gre_flags(p->o_flags);
824 return 0;
825}
826
827/* Nice toy. Unfortunately, useless in real life :-)
828 It allows to construct virtual multiprotocol broadcast "LAN"
829 over the Internet, provided multicast routing is tuned.
830
831
832 I have no idea was this bicycle invented before me,
833 so that I had to set ARPHRD_IPGRE to a random value.
834 I have an impression, that Cisco could make something similar,
835 but this feature is apparently missing in IOS<=11.2(8).
836
837 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
838 with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
839
840 ping -t 255 224.66.66.66
841
842 If nobody answers, mbone does not work.
843
844 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
845 ip addr add 10.66.66.<somewhat>/24 dev Universe
846 ifconfig Universe up
847 ifconfig Universe add fe80::<Your_real_addr>/10
848 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
849 ftp 10.66.66.66
850 ...
851 ftp fec0:6666:6666::193.233.7.65
852 ...
853 */
854static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
855 unsigned short type,
856 const void *daddr, const void *saddr, unsigned int len)
857{
858 struct ip_tunnel *t = netdev_priv(dev);
859 struct iphdr *iph;
860 struct gre_base_hdr *greh;
861
862 iph = skb_push(skb, t->hlen + sizeof(*iph));
863 greh = (struct gre_base_hdr *)(iph+1);
864 greh->flags = gre_tnl_flags_to_gre_flags(t->parms.o_flags);
865 greh->protocol = htons(type);
866
867 memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
868
869 /* Set the source hardware address. */
870 if (saddr)
871 memcpy(&iph->saddr, saddr, 4);
872 if (daddr)
873 memcpy(&iph->daddr, daddr, 4);
874 if (iph->daddr)
875 return t->hlen + sizeof(*iph);
876
877 return -(t->hlen + sizeof(*iph));
878}
879
880static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
881{
882 const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
883 memcpy(haddr, &iph->saddr, 4);
884 return 4;
885}
886
887static const struct header_ops ipgre_header_ops = {
888 .create = ipgre_header,
889 .parse = ipgre_header_parse,
890};
891
892#ifdef CONFIG_NET_IPGRE_BROADCAST
893static int ipgre_open(struct net_device *dev)
894{
895 struct ip_tunnel *t = netdev_priv(dev);
896
897 if (ipv4_is_multicast(t->parms.iph.daddr)) {
898 struct flowi4 fl4;
899 struct rtable *rt;
900
901 rt = ip_route_output_gre(t->net, &fl4,
902 t->parms.iph.daddr,
903 t->parms.iph.saddr,
904 t->parms.o_key,
905 RT_TOS(t->parms.iph.tos),
906 t->parms.link);
907 if (IS_ERR(rt))
908 return -EADDRNOTAVAIL;
909 dev = rt->dst.dev;
910 ip_rt_put(rt);
911 if (!__in_dev_get_rtnl(dev))
912 return -EADDRNOTAVAIL;
913 t->mlink = dev->ifindex;
914 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
915 }
916 return 0;
917}
918
919static int ipgre_close(struct net_device *dev)
920{
921 struct ip_tunnel *t = netdev_priv(dev);
922
923 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
924 struct in_device *in_dev;
925 in_dev = inetdev_by_index(t->net, t->mlink);
926 if (in_dev)
927 ip_mc_dec_group(in_dev, t->parms.iph.daddr);
928 }
929 return 0;
930}
931#endif
932
933static const struct net_device_ops ipgre_netdev_ops = {
934 .ndo_init = ipgre_tunnel_init,
935 .ndo_uninit = ip_tunnel_uninit,
936#ifdef CONFIG_NET_IPGRE_BROADCAST
937 .ndo_open = ipgre_open,
938 .ndo_stop = ipgre_close,
939#endif
940 .ndo_start_xmit = ipgre_xmit,
941 .ndo_siocdevprivate = ip_tunnel_siocdevprivate,
942 .ndo_change_mtu = ip_tunnel_change_mtu,
943 .ndo_get_stats64 = dev_get_tstats64,
944 .ndo_get_iflink = ip_tunnel_get_iflink,
945 .ndo_tunnel_ctl = ipgre_tunnel_ctl,
946};
947
948#define GRE_FEATURES (NETIF_F_SG | \
949 NETIF_F_FRAGLIST | \
950 NETIF_F_HIGHDMA | \
951 NETIF_F_HW_CSUM)
952
953static void ipgre_tunnel_setup(struct net_device *dev)
954{
955 dev->netdev_ops = &ipgre_netdev_ops;
956 dev->type = ARPHRD_IPGRE;
957 ip_tunnel_setup(dev, ipgre_net_id);
958}
959
960static void __gre_tunnel_init(struct net_device *dev)
961{
962 struct ip_tunnel *tunnel;
963 __be16 flags;
964
965 tunnel = netdev_priv(dev);
966 tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
967 tunnel->parms.iph.protocol = IPPROTO_GRE;
968
969 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
970 dev->needed_headroom = tunnel->hlen + sizeof(tunnel->parms.iph);
971
972 dev->features |= GRE_FEATURES | NETIF_F_LLTX;
973 dev->hw_features |= GRE_FEATURES;
974
975 flags = tunnel->parms.o_flags;
976
977 /* TCP offload with GRE SEQ is not supported, nor can we support 2
978 * levels of outer headers requiring an update.
979 */
980 if (flags & TUNNEL_SEQ)
981 return;
982 if (flags & TUNNEL_CSUM && tunnel->encap.type != TUNNEL_ENCAP_NONE)
983 return;
984
985 dev->features |= NETIF_F_GSO_SOFTWARE;
986 dev->hw_features |= NETIF_F_GSO_SOFTWARE;
987}
988
989static int ipgre_tunnel_init(struct net_device *dev)
990{
991 struct ip_tunnel *tunnel = netdev_priv(dev);
992 struct iphdr *iph = &tunnel->parms.iph;
993
994 __gre_tunnel_init(dev);
995
996 __dev_addr_set(dev, &iph->saddr, 4);
997 memcpy(dev->broadcast, &iph->daddr, 4);
998
999 dev->flags = IFF_NOARP;
1000 netif_keep_dst(dev);
1001 dev->addr_len = 4;
1002
1003 if (iph->daddr && !tunnel->collect_md) {
1004#ifdef CONFIG_NET_IPGRE_BROADCAST
1005 if (ipv4_is_multicast(iph->daddr)) {
1006 if (!iph->saddr)
1007 return -EINVAL;
1008 dev->flags = IFF_BROADCAST;
1009 dev->header_ops = &ipgre_header_ops;
1010 dev->hard_header_len = tunnel->hlen + sizeof(*iph);
1011 dev->needed_headroom = 0;
1012 }
1013#endif
1014 } else if (!tunnel->collect_md) {
1015 dev->header_ops = &ipgre_header_ops;
1016 dev->hard_header_len = tunnel->hlen + sizeof(*iph);
1017 dev->needed_headroom = 0;
1018 }
1019
1020 return ip_tunnel_init(dev);
1021}
1022
1023static const struct gre_protocol ipgre_protocol = {
1024 .handler = gre_rcv,
1025 .err_handler = gre_err,
1026};
1027
1028static int __net_init ipgre_init_net(struct net *net)
1029{
1030 return ip_tunnel_init_net(net, ipgre_net_id, &ipgre_link_ops, NULL);
1031}
1032
1033static void __net_exit ipgre_exit_batch_rtnl(struct list_head *list_net,
1034 struct list_head *dev_to_kill)
1035{
1036 ip_tunnel_delete_nets(list_net, ipgre_net_id, &ipgre_link_ops,
1037 dev_to_kill);
1038}
1039
1040static struct pernet_operations ipgre_net_ops = {
1041 .init = ipgre_init_net,
1042 .exit_batch_rtnl = ipgre_exit_batch_rtnl,
1043 .id = &ipgre_net_id,
1044 .size = sizeof(struct ip_tunnel_net),
1045};
1046
1047static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
1048 struct netlink_ext_ack *extack)
1049{
1050 __be16 flags;
1051
1052 if (!data)
1053 return 0;
1054
1055 flags = 0;
1056 if (data[IFLA_GRE_IFLAGS])
1057 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1058 if (data[IFLA_GRE_OFLAGS])
1059 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1060 if (flags & (GRE_VERSION|GRE_ROUTING))
1061 return -EINVAL;
1062
1063 if (data[IFLA_GRE_COLLECT_METADATA] &&
1064 data[IFLA_GRE_ENCAP_TYPE] &&
1065 nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE)
1066 return -EINVAL;
1067
1068 return 0;
1069}
1070
1071static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[],
1072 struct netlink_ext_ack *extack)
1073{
1074 __be32 daddr;
1075
1076 if (tb[IFLA_ADDRESS]) {
1077 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1078 return -EINVAL;
1079 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1080 return -EADDRNOTAVAIL;
1081 }
1082
1083 if (!data)
1084 goto out;
1085
1086 if (data[IFLA_GRE_REMOTE]) {
1087 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
1088 if (!daddr)
1089 return -EINVAL;
1090 }
1091
1092out:
1093 return ipgre_tunnel_validate(tb, data, extack);
1094}
1095
1096static int erspan_validate(struct nlattr *tb[], struct nlattr *data[],
1097 struct netlink_ext_ack *extack)
1098{
1099 __be16 flags = 0;
1100 int ret;
1101
1102 if (!data)
1103 return 0;
1104
1105 ret = ipgre_tap_validate(tb, data, extack);
1106 if (ret)
1107 return ret;
1108
1109 if (data[IFLA_GRE_ERSPAN_VER] &&
1110 nla_get_u8(data[IFLA_GRE_ERSPAN_VER]) == 0)
1111 return 0;
1112
1113 /* ERSPAN type II/III should only have GRE sequence and key flag */
1114 if (data[IFLA_GRE_OFLAGS])
1115 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1116 if (data[IFLA_GRE_IFLAGS])
1117 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1118 if (!data[IFLA_GRE_COLLECT_METADATA] &&
1119 flags != (GRE_SEQ | GRE_KEY))
1120 return -EINVAL;
1121
1122 /* ERSPAN Session ID only has 10-bit. Since we reuse
1123 * 32-bit key field as ID, check it's range.
1124 */
1125 if (data[IFLA_GRE_IKEY] &&
1126 (ntohl(nla_get_be32(data[IFLA_GRE_IKEY])) & ~ID_MASK))
1127 return -EINVAL;
1128
1129 if (data[IFLA_GRE_OKEY] &&
1130 (ntohl(nla_get_be32(data[IFLA_GRE_OKEY])) & ~ID_MASK))
1131 return -EINVAL;
1132
1133 return 0;
1134}
1135
1136static int ipgre_netlink_parms(struct net_device *dev,
1137 struct nlattr *data[],
1138 struct nlattr *tb[],
1139 struct ip_tunnel_parm *parms,
1140 __u32 *fwmark)
1141{
1142 struct ip_tunnel *t = netdev_priv(dev);
1143
1144 memset(parms, 0, sizeof(*parms));
1145
1146 parms->iph.protocol = IPPROTO_GRE;
1147
1148 if (!data)
1149 return 0;
1150
1151 if (data[IFLA_GRE_LINK])
1152 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1153
1154 if (data[IFLA_GRE_IFLAGS])
1155 parms->i_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_IFLAGS]));
1156
1157 if (data[IFLA_GRE_OFLAGS])
1158 parms->o_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_OFLAGS]));
1159
1160 if (data[IFLA_GRE_IKEY])
1161 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1162
1163 if (data[IFLA_GRE_OKEY])
1164 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1165
1166 if (data[IFLA_GRE_LOCAL])
1167 parms->iph.saddr = nla_get_in_addr(data[IFLA_GRE_LOCAL]);
1168
1169 if (data[IFLA_GRE_REMOTE])
1170 parms->iph.daddr = nla_get_in_addr(data[IFLA_GRE_REMOTE]);
1171
1172 if (data[IFLA_GRE_TTL])
1173 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1174
1175 if (data[IFLA_GRE_TOS])
1176 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1177
1178 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC])) {
1179 if (t->ignore_df)
1180 return -EINVAL;
1181 parms->iph.frag_off = htons(IP_DF);
1182 }
1183
1184 if (data[IFLA_GRE_COLLECT_METADATA]) {
1185 t->collect_md = true;
1186 if (dev->type == ARPHRD_IPGRE)
1187 dev->type = ARPHRD_NONE;
1188 }
1189
1190 if (data[IFLA_GRE_IGNORE_DF]) {
1191 if (nla_get_u8(data[IFLA_GRE_IGNORE_DF])
1192 && (parms->iph.frag_off & htons(IP_DF)))
1193 return -EINVAL;
1194 t->ignore_df = !!nla_get_u8(data[IFLA_GRE_IGNORE_DF]);
1195 }
1196
1197 if (data[IFLA_GRE_FWMARK])
1198 *fwmark = nla_get_u32(data[IFLA_GRE_FWMARK]);
1199
1200 return 0;
1201}
1202
1203static int erspan_netlink_parms(struct net_device *dev,
1204 struct nlattr *data[],
1205 struct nlattr *tb[],
1206 struct ip_tunnel_parm *parms,
1207 __u32 *fwmark)
1208{
1209 struct ip_tunnel *t = netdev_priv(dev);
1210 int err;
1211
1212 err = ipgre_netlink_parms(dev, data, tb, parms, fwmark);
1213 if (err)
1214 return err;
1215 if (!data)
1216 return 0;
1217
1218 if (data[IFLA_GRE_ERSPAN_VER]) {
1219 t->erspan_ver = nla_get_u8(data[IFLA_GRE_ERSPAN_VER]);
1220
1221 if (t->erspan_ver > 2)
1222 return -EINVAL;
1223 }
1224
1225 if (t->erspan_ver == 1) {
1226 if (data[IFLA_GRE_ERSPAN_INDEX]) {
1227 t->index = nla_get_u32(data[IFLA_GRE_ERSPAN_INDEX]);
1228 if (t->index & ~INDEX_MASK)
1229 return -EINVAL;
1230 }
1231 } else if (t->erspan_ver == 2) {
1232 if (data[IFLA_GRE_ERSPAN_DIR]) {
1233 t->dir = nla_get_u8(data[IFLA_GRE_ERSPAN_DIR]);
1234 if (t->dir & ~(DIR_MASK >> DIR_OFFSET))
1235 return -EINVAL;
1236 }
1237 if (data[IFLA_GRE_ERSPAN_HWID]) {
1238 t->hwid = nla_get_u16(data[IFLA_GRE_ERSPAN_HWID]);
1239 if (t->hwid & ~(HWID_MASK >> HWID_OFFSET))
1240 return -EINVAL;
1241 }
1242 }
1243
1244 return 0;
1245}
1246
1247/* This function returns true when ENCAP attributes are present in the nl msg */
1248static bool ipgre_netlink_encap_parms(struct nlattr *data[],
1249 struct ip_tunnel_encap *ipencap)
1250{
1251 bool ret = false;
1252
1253 memset(ipencap, 0, sizeof(*ipencap));
1254
1255 if (!data)
1256 return ret;
1257
1258 if (data[IFLA_GRE_ENCAP_TYPE]) {
1259 ret = true;
1260 ipencap->type = nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]);
1261 }
1262
1263 if (data[IFLA_GRE_ENCAP_FLAGS]) {
1264 ret = true;
1265 ipencap->flags = nla_get_u16(data[IFLA_GRE_ENCAP_FLAGS]);
1266 }
1267
1268 if (data[IFLA_GRE_ENCAP_SPORT]) {
1269 ret = true;
1270 ipencap->sport = nla_get_be16(data[IFLA_GRE_ENCAP_SPORT]);
1271 }
1272
1273 if (data[IFLA_GRE_ENCAP_DPORT]) {
1274 ret = true;
1275 ipencap->dport = nla_get_be16(data[IFLA_GRE_ENCAP_DPORT]);
1276 }
1277
1278 return ret;
1279}
1280
1281static int gre_tap_init(struct net_device *dev)
1282{
1283 __gre_tunnel_init(dev);
1284 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1285 netif_keep_dst(dev);
1286
1287 return ip_tunnel_init(dev);
1288}
1289
1290static const struct net_device_ops gre_tap_netdev_ops = {
1291 .ndo_init = gre_tap_init,
1292 .ndo_uninit = ip_tunnel_uninit,
1293 .ndo_start_xmit = gre_tap_xmit,
1294 .ndo_set_mac_address = eth_mac_addr,
1295 .ndo_validate_addr = eth_validate_addr,
1296 .ndo_change_mtu = ip_tunnel_change_mtu,
1297 .ndo_get_stats64 = dev_get_tstats64,
1298 .ndo_get_iflink = ip_tunnel_get_iflink,
1299 .ndo_fill_metadata_dst = gre_fill_metadata_dst,
1300};
1301
1302static int erspan_tunnel_init(struct net_device *dev)
1303{
1304 struct ip_tunnel *tunnel = netdev_priv(dev);
1305
1306 if (tunnel->erspan_ver == 0)
1307 tunnel->tun_hlen = 4; /* 4-byte GRE hdr. */
1308 else
1309 tunnel->tun_hlen = 8; /* 8-byte GRE hdr. */
1310
1311 tunnel->parms.iph.protocol = IPPROTO_GRE;
1312 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
1313 erspan_hdr_len(tunnel->erspan_ver);
1314
1315 dev->features |= GRE_FEATURES;
1316 dev->hw_features |= GRE_FEATURES;
1317 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1318 netif_keep_dst(dev);
1319
1320 return ip_tunnel_init(dev);
1321}
1322
1323static const struct net_device_ops erspan_netdev_ops = {
1324 .ndo_init = erspan_tunnel_init,
1325 .ndo_uninit = ip_tunnel_uninit,
1326 .ndo_start_xmit = erspan_xmit,
1327 .ndo_set_mac_address = eth_mac_addr,
1328 .ndo_validate_addr = eth_validate_addr,
1329 .ndo_change_mtu = ip_tunnel_change_mtu,
1330 .ndo_get_stats64 = dev_get_tstats64,
1331 .ndo_get_iflink = ip_tunnel_get_iflink,
1332 .ndo_fill_metadata_dst = gre_fill_metadata_dst,
1333};
1334
1335static void ipgre_tap_setup(struct net_device *dev)
1336{
1337 ether_setup(dev);
1338 dev->max_mtu = 0;
1339 dev->netdev_ops = &gre_tap_netdev_ops;
1340 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1341 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1342 ip_tunnel_setup(dev, gre_tap_net_id);
1343}
1344
1345static int
1346ipgre_newlink_encap_setup(struct net_device *dev, struct nlattr *data[])
1347{
1348 struct ip_tunnel_encap ipencap;
1349
1350 if (ipgre_netlink_encap_parms(data, &ipencap)) {
1351 struct ip_tunnel *t = netdev_priv(dev);
1352 int err = ip_tunnel_encap_setup(t, &ipencap);
1353
1354 if (err < 0)
1355 return err;
1356 }
1357
1358 return 0;
1359}
1360
1361static int ipgre_newlink(struct net *src_net, struct net_device *dev,
1362 struct nlattr *tb[], struct nlattr *data[],
1363 struct netlink_ext_ack *extack)
1364{
1365 struct ip_tunnel_parm p;
1366 __u32 fwmark = 0;
1367 int err;
1368
1369 err = ipgre_newlink_encap_setup(dev, data);
1370 if (err)
1371 return err;
1372
1373 err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);
1374 if (err < 0)
1375 return err;
1376 return ip_tunnel_newlink(dev, tb, &p, fwmark);
1377}
1378
1379static int erspan_newlink(struct net *src_net, struct net_device *dev,
1380 struct nlattr *tb[], struct nlattr *data[],
1381 struct netlink_ext_ack *extack)
1382{
1383 struct ip_tunnel_parm p;
1384 __u32 fwmark = 0;
1385 int err;
1386
1387 err = ipgre_newlink_encap_setup(dev, data);
1388 if (err)
1389 return err;
1390
1391 err = erspan_netlink_parms(dev, data, tb, &p, &fwmark);
1392 if (err)
1393 return err;
1394 return ip_tunnel_newlink(dev, tb, &p, fwmark);
1395}
1396
1397static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1398 struct nlattr *data[],
1399 struct netlink_ext_ack *extack)
1400{
1401 struct ip_tunnel *t = netdev_priv(dev);
1402 __u32 fwmark = t->fwmark;
1403 struct ip_tunnel_parm p;
1404 int err;
1405
1406 err = ipgre_newlink_encap_setup(dev, data);
1407 if (err)
1408 return err;
1409
1410 err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);
1411 if (err < 0)
1412 return err;
1413
1414 err = ip_tunnel_changelink(dev, tb, &p, fwmark);
1415 if (err < 0)
1416 return err;
1417
1418 t->parms.i_flags = p.i_flags;
1419 t->parms.o_flags = p.o_flags;
1420
1421 ipgre_link_update(dev, !tb[IFLA_MTU]);
1422
1423 return 0;
1424}
1425
1426static int erspan_changelink(struct net_device *dev, struct nlattr *tb[],
1427 struct nlattr *data[],
1428 struct netlink_ext_ack *extack)
1429{
1430 struct ip_tunnel *t = netdev_priv(dev);
1431 __u32 fwmark = t->fwmark;
1432 struct ip_tunnel_parm p;
1433 int err;
1434
1435 err = ipgre_newlink_encap_setup(dev, data);
1436 if (err)
1437 return err;
1438
1439 err = erspan_netlink_parms(dev, data, tb, &p, &fwmark);
1440 if (err < 0)
1441 return err;
1442
1443 err = ip_tunnel_changelink(dev, tb, &p, fwmark);
1444 if (err < 0)
1445 return err;
1446
1447 t->parms.i_flags = p.i_flags;
1448 t->parms.o_flags = p.o_flags;
1449
1450 return 0;
1451}
1452
1453static size_t ipgre_get_size(const struct net_device *dev)
1454{
1455 return
1456 /* IFLA_GRE_LINK */
1457 nla_total_size(4) +
1458 /* IFLA_GRE_IFLAGS */
1459 nla_total_size(2) +
1460 /* IFLA_GRE_OFLAGS */
1461 nla_total_size(2) +
1462 /* IFLA_GRE_IKEY */
1463 nla_total_size(4) +
1464 /* IFLA_GRE_OKEY */
1465 nla_total_size(4) +
1466 /* IFLA_GRE_LOCAL */
1467 nla_total_size(4) +
1468 /* IFLA_GRE_REMOTE */
1469 nla_total_size(4) +
1470 /* IFLA_GRE_TTL */
1471 nla_total_size(1) +
1472 /* IFLA_GRE_TOS */
1473 nla_total_size(1) +
1474 /* IFLA_GRE_PMTUDISC */
1475 nla_total_size(1) +
1476 /* IFLA_GRE_ENCAP_TYPE */
1477 nla_total_size(2) +
1478 /* IFLA_GRE_ENCAP_FLAGS */
1479 nla_total_size(2) +
1480 /* IFLA_GRE_ENCAP_SPORT */
1481 nla_total_size(2) +
1482 /* IFLA_GRE_ENCAP_DPORT */
1483 nla_total_size(2) +
1484 /* IFLA_GRE_COLLECT_METADATA */
1485 nla_total_size(0) +
1486 /* IFLA_GRE_IGNORE_DF */
1487 nla_total_size(1) +
1488 /* IFLA_GRE_FWMARK */
1489 nla_total_size(4) +
1490 /* IFLA_GRE_ERSPAN_INDEX */
1491 nla_total_size(4) +
1492 /* IFLA_GRE_ERSPAN_VER */
1493 nla_total_size(1) +
1494 /* IFLA_GRE_ERSPAN_DIR */
1495 nla_total_size(1) +
1496 /* IFLA_GRE_ERSPAN_HWID */
1497 nla_total_size(2) +
1498 0;
1499}
1500
1501static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1502{
1503 struct ip_tunnel *t = netdev_priv(dev);
1504 struct ip_tunnel_parm *p = &t->parms;
1505 __be16 o_flags = p->o_flags;
1506
1507 if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
1508 nla_put_be16(skb, IFLA_GRE_IFLAGS,
1509 gre_tnl_flags_to_gre_flags(p->i_flags)) ||
1510 nla_put_be16(skb, IFLA_GRE_OFLAGS,
1511 gre_tnl_flags_to_gre_flags(o_flags)) ||
1512 nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
1513 nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
1514 nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
1515 nla_put_in_addr(skb, IFLA_GRE_REMOTE, p->iph.daddr) ||
1516 nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) ||
1517 nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) ||
1518 nla_put_u8(skb, IFLA_GRE_PMTUDISC,
1519 !!(p->iph.frag_off & htons(IP_DF))) ||
1520 nla_put_u32(skb, IFLA_GRE_FWMARK, t->fwmark))
1521 goto nla_put_failure;
1522
1523 if (nla_put_u16(skb, IFLA_GRE_ENCAP_TYPE,
1524 t->encap.type) ||
1525 nla_put_be16(skb, IFLA_GRE_ENCAP_SPORT,
1526 t->encap.sport) ||
1527 nla_put_be16(skb, IFLA_GRE_ENCAP_DPORT,
1528 t->encap.dport) ||
1529 nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS,
1530 t->encap.flags))
1531 goto nla_put_failure;
1532
1533 if (nla_put_u8(skb, IFLA_GRE_IGNORE_DF, t->ignore_df))
1534 goto nla_put_failure;
1535
1536 if (t->collect_md) {
1537 if (nla_put_flag(skb, IFLA_GRE_COLLECT_METADATA))
1538 goto nla_put_failure;
1539 }
1540
1541 return 0;
1542
1543nla_put_failure:
1544 return -EMSGSIZE;
1545}
1546
1547static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev)
1548{
1549 struct ip_tunnel *t = netdev_priv(dev);
1550
1551 if (t->erspan_ver <= 2) {
1552 if (t->erspan_ver != 0 && !t->collect_md)
1553 t->parms.o_flags |= TUNNEL_KEY;
1554
1555 if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
1556 goto nla_put_failure;
1557
1558 if (t->erspan_ver == 1) {
1559 if (nla_put_u32(skb, IFLA_GRE_ERSPAN_INDEX, t->index))
1560 goto nla_put_failure;
1561 } else if (t->erspan_ver == 2) {
1562 if (nla_put_u8(skb, IFLA_GRE_ERSPAN_DIR, t->dir))
1563 goto nla_put_failure;
1564 if (nla_put_u16(skb, IFLA_GRE_ERSPAN_HWID, t->hwid))
1565 goto nla_put_failure;
1566 }
1567 }
1568
1569 return ipgre_fill_info(skb, dev);
1570
1571nla_put_failure:
1572 return -EMSGSIZE;
1573}
1574
1575static void erspan_setup(struct net_device *dev)
1576{
1577 struct ip_tunnel *t = netdev_priv(dev);
1578
1579 ether_setup(dev);
1580 dev->max_mtu = 0;
1581 dev->netdev_ops = &erspan_netdev_ops;
1582 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1583 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1584 ip_tunnel_setup(dev, erspan_net_id);
1585 t->erspan_ver = 1;
1586}
1587
1588static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1589 [IFLA_GRE_LINK] = { .type = NLA_U32 },
1590 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 },
1591 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 },
1592 [IFLA_GRE_IKEY] = { .type = NLA_U32 },
1593 [IFLA_GRE_OKEY] = { .type = NLA_U32 },
1594 [IFLA_GRE_LOCAL] = { .len = sizeof_field(struct iphdr, saddr) },
1595 [IFLA_GRE_REMOTE] = { .len = sizeof_field(struct iphdr, daddr) },
1596 [IFLA_GRE_TTL] = { .type = NLA_U8 },
1597 [IFLA_GRE_TOS] = { .type = NLA_U8 },
1598 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 },
1599 [IFLA_GRE_ENCAP_TYPE] = { .type = NLA_U16 },
1600 [IFLA_GRE_ENCAP_FLAGS] = { .type = NLA_U16 },
1601 [IFLA_GRE_ENCAP_SPORT] = { .type = NLA_U16 },
1602 [IFLA_GRE_ENCAP_DPORT] = { .type = NLA_U16 },
1603 [IFLA_GRE_COLLECT_METADATA] = { .type = NLA_FLAG },
1604 [IFLA_GRE_IGNORE_DF] = { .type = NLA_U8 },
1605 [IFLA_GRE_FWMARK] = { .type = NLA_U32 },
1606 [IFLA_GRE_ERSPAN_INDEX] = { .type = NLA_U32 },
1607 [IFLA_GRE_ERSPAN_VER] = { .type = NLA_U8 },
1608 [IFLA_GRE_ERSPAN_DIR] = { .type = NLA_U8 },
1609 [IFLA_GRE_ERSPAN_HWID] = { .type = NLA_U16 },
1610};
1611
1612static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1613 .kind = "gre",
1614 .maxtype = IFLA_GRE_MAX,
1615 .policy = ipgre_policy,
1616 .priv_size = sizeof(struct ip_tunnel),
1617 .setup = ipgre_tunnel_setup,
1618 .validate = ipgre_tunnel_validate,
1619 .newlink = ipgre_newlink,
1620 .changelink = ipgre_changelink,
1621 .dellink = ip_tunnel_dellink,
1622 .get_size = ipgre_get_size,
1623 .fill_info = ipgre_fill_info,
1624 .get_link_net = ip_tunnel_get_link_net,
1625};
1626
1627static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1628 .kind = "gretap",
1629 .maxtype = IFLA_GRE_MAX,
1630 .policy = ipgre_policy,
1631 .priv_size = sizeof(struct ip_tunnel),
1632 .setup = ipgre_tap_setup,
1633 .validate = ipgre_tap_validate,
1634 .newlink = ipgre_newlink,
1635 .changelink = ipgre_changelink,
1636 .dellink = ip_tunnel_dellink,
1637 .get_size = ipgre_get_size,
1638 .fill_info = ipgre_fill_info,
1639 .get_link_net = ip_tunnel_get_link_net,
1640};
1641
1642static struct rtnl_link_ops erspan_link_ops __read_mostly = {
1643 .kind = "erspan",
1644 .maxtype = IFLA_GRE_MAX,
1645 .policy = ipgre_policy,
1646 .priv_size = sizeof(struct ip_tunnel),
1647 .setup = erspan_setup,
1648 .validate = erspan_validate,
1649 .newlink = erspan_newlink,
1650 .changelink = erspan_changelink,
1651 .dellink = ip_tunnel_dellink,
1652 .get_size = ipgre_get_size,
1653 .fill_info = erspan_fill_info,
1654 .get_link_net = ip_tunnel_get_link_net,
1655};
1656
1657struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
1658 u8 name_assign_type)
1659{
1660 struct nlattr *tb[IFLA_MAX + 1];
1661 struct net_device *dev;
1662 LIST_HEAD(list_kill);
1663 struct ip_tunnel *t;
1664 int err;
1665
1666 memset(&tb, 0, sizeof(tb));
1667
1668 dev = rtnl_create_link(net, name, name_assign_type,
1669 &ipgre_tap_ops, tb, NULL);
1670 if (IS_ERR(dev))
1671 return dev;
1672
1673 /* Configure flow based GRE device. */
1674 t = netdev_priv(dev);
1675 t->collect_md = true;
1676
1677 err = ipgre_newlink(net, dev, tb, NULL, NULL);
1678 if (err < 0) {
1679 free_netdev(dev);
1680 return ERR_PTR(err);
1681 }
1682
1683 /* openvswitch users expect packet sizes to be unrestricted,
1684 * so set the largest MTU we can.
1685 */
1686 err = __ip_tunnel_change_mtu(dev, IP_MAX_MTU, false);
1687 if (err)
1688 goto out;
1689
1690 err = rtnl_configure_link(dev, NULL, 0, NULL);
1691 if (err < 0)
1692 goto out;
1693
1694 return dev;
1695out:
1696 ip_tunnel_dellink(dev, &list_kill);
1697 unregister_netdevice_many(&list_kill);
1698 return ERR_PTR(err);
1699}
1700EXPORT_SYMBOL_GPL(gretap_fb_dev_create);
1701
1702static int __net_init ipgre_tap_init_net(struct net *net)
1703{
1704 return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0");
1705}
1706
1707static void __net_exit ipgre_tap_exit_batch_rtnl(struct list_head *list_net,
1708 struct list_head *dev_to_kill)
1709{
1710 ip_tunnel_delete_nets(list_net, gre_tap_net_id, &ipgre_tap_ops,
1711 dev_to_kill);
1712}
1713
1714static struct pernet_operations ipgre_tap_net_ops = {
1715 .init = ipgre_tap_init_net,
1716 .exit_batch_rtnl = ipgre_tap_exit_batch_rtnl,
1717 .id = &gre_tap_net_id,
1718 .size = sizeof(struct ip_tunnel_net),
1719};
1720
1721static int __net_init erspan_init_net(struct net *net)
1722{
1723 return ip_tunnel_init_net(net, erspan_net_id,
1724 &erspan_link_ops, "erspan0");
1725}
1726
1727static void __net_exit erspan_exit_batch_rtnl(struct list_head *net_list,
1728 struct list_head *dev_to_kill)
1729{
1730 ip_tunnel_delete_nets(net_list, erspan_net_id, &erspan_link_ops,
1731 dev_to_kill);
1732}
1733
1734static struct pernet_operations erspan_net_ops = {
1735 .init = erspan_init_net,
1736 .exit_batch_rtnl = erspan_exit_batch_rtnl,
1737 .id = &erspan_net_id,
1738 .size = sizeof(struct ip_tunnel_net),
1739};
1740
1741static int __init ipgre_init(void)
1742{
1743 int err;
1744
1745 pr_info("GRE over IPv4 tunneling driver\n");
1746
1747 err = register_pernet_device(&ipgre_net_ops);
1748 if (err < 0)
1749 return err;
1750
1751 err = register_pernet_device(&ipgre_tap_net_ops);
1752 if (err < 0)
1753 goto pnet_tap_failed;
1754
1755 err = register_pernet_device(&erspan_net_ops);
1756 if (err < 0)
1757 goto pnet_erspan_failed;
1758
1759 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
1760 if (err < 0) {
1761 pr_info("%s: can't add protocol\n", __func__);
1762 goto add_proto_failed;
1763 }
1764
1765 err = rtnl_link_register(&ipgre_link_ops);
1766 if (err < 0)
1767 goto rtnl_link_failed;
1768
1769 err = rtnl_link_register(&ipgre_tap_ops);
1770 if (err < 0)
1771 goto tap_ops_failed;
1772
1773 err = rtnl_link_register(&erspan_link_ops);
1774 if (err < 0)
1775 goto erspan_link_failed;
1776
1777 return 0;
1778
1779erspan_link_failed:
1780 rtnl_link_unregister(&ipgre_tap_ops);
1781tap_ops_failed:
1782 rtnl_link_unregister(&ipgre_link_ops);
1783rtnl_link_failed:
1784 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1785add_proto_failed:
1786 unregister_pernet_device(&erspan_net_ops);
1787pnet_erspan_failed:
1788 unregister_pernet_device(&ipgre_tap_net_ops);
1789pnet_tap_failed:
1790 unregister_pernet_device(&ipgre_net_ops);
1791 return err;
1792}
1793
1794static void __exit ipgre_fini(void)
1795{
1796 rtnl_link_unregister(&ipgre_tap_ops);
1797 rtnl_link_unregister(&ipgre_link_ops);
1798 rtnl_link_unregister(&erspan_link_ops);
1799 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1800 unregister_pernet_device(&ipgre_tap_net_ops);
1801 unregister_pernet_device(&ipgre_net_ops);
1802 unregister_pernet_device(&erspan_net_ops);
1803}
1804
1805module_init(ipgre_init);
1806module_exit(ipgre_fini);
1807MODULE_DESCRIPTION("IPv4 GRE tunnels over IP library");
1808MODULE_LICENSE("GPL");
1809MODULE_ALIAS_RTNL_LINK("gre");
1810MODULE_ALIAS_RTNL_LINK("gretap");
1811MODULE_ALIAS_RTNL_LINK("erspan");
1812MODULE_ALIAS_NETDEV("gre0");
1813MODULE_ALIAS_NETDEV("gretap0");
1814MODULE_ALIAS_NETDEV("erspan0");