xref: /openbmc/linux/net/ipv6/ip6_gre.c (revision 8b235f2f)
1 /*
2  *	GRE over IPv6 protocol decoder.
3  *
4  *	Authors: Dmitry Kozlov (xeb@mail.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 <linux/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 #include <linux/hash.h>
36 #include <linux/if_tunnel.h>
37 #include <linux/ip6_tunnel.h>
38 
39 #include <net/sock.h>
40 #include <net/ip.h>
41 #include <net/ip_tunnels.h>
42 #include <net/icmp.h>
43 #include <net/protocol.h>
44 #include <net/addrconf.h>
45 #include <net/arp.h>
46 #include <net/checksum.h>
47 #include <net/dsfield.h>
48 #include <net/inet_ecn.h>
49 #include <net/xfrm.h>
50 #include <net/net_namespace.h>
51 #include <net/netns/generic.h>
52 #include <net/rtnetlink.h>
53 
54 #include <net/ipv6.h>
55 #include <net/ip6_fib.h>
56 #include <net/ip6_route.h>
57 #include <net/ip6_tunnel.h>
58 
59 
60 static bool log_ecn_error = true;
61 module_param(log_ecn_error, bool, 0644);
62 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
63 
64 #define HASH_SIZE_SHIFT  5
65 #define HASH_SIZE (1 << HASH_SIZE_SHIFT)
66 
67 static int ip6gre_net_id __read_mostly;
68 struct ip6gre_net {
69 	struct ip6_tnl __rcu *tunnels[4][HASH_SIZE];
70 
71 	struct net_device *fb_tunnel_dev;
72 };
73 
74 static struct rtnl_link_ops ip6gre_link_ops __read_mostly;
75 static struct rtnl_link_ops ip6gre_tap_ops __read_mostly;
76 static int ip6gre_tunnel_init(struct net_device *dev);
77 static void ip6gre_tunnel_setup(struct net_device *dev);
78 static void ip6gre_tunnel_link(struct ip6gre_net *ign, struct ip6_tnl *t);
79 static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu);
80 
81 /* Tunnel hash table */
82 
83 /*
84    4 hash tables:
85 
86    3: (remote,local)
87    2: (remote,*)
88    1: (*,local)
89    0: (*,*)
90 
91    We require exact key match i.e. if a key is present in packet
92    it will match only tunnel with the same key; if it is not present,
93    it will match only keyless tunnel.
94 
95    All keysless packets, if not matched configured keyless tunnels
96    will match fallback tunnel.
97  */
98 
99 #define HASH_KEY(key) (((__force u32)key^((__force u32)key>>4))&(HASH_SIZE - 1))
100 static u32 HASH_ADDR(const struct in6_addr *addr)
101 {
102 	u32 hash = ipv6_addr_hash(addr);
103 
104 	return hash_32(hash, HASH_SIZE_SHIFT);
105 }
106 
107 #define tunnels_r_l	tunnels[3]
108 #define tunnels_r	tunnels[2]
109 #define tunnels_l	tunnels[1]
110 #define tunnels_wc	tunnels[0]
111 
112 /* Given src, dst and key, find appropriate for input tunnel. */
113 
114 static struct ip6_tnl *ip6gre_tunnel_lookup(struct net_device *dev,
115 		const struct in6_addr *remote, const struct in6_addr *local,
116 		__be32 key, __be16 gre_proto)
117 {
118 	struct net *net = dev_net(dev);
119 	int link = dev->ifindex;
120 	unsigned int h0 = HASH_ADDR(remote);
121 	unsigned int h1 = HASH_KEY(key);
122 	struct ip6_tnl *t, *cand = NULL;
123 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
124 	int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
125 		       ARPHRD_ETHER : ARPHRD_IP6GRE;
126 	int score, cand_score = 4;
127 
128 	for_each_ip_tunnel_rcu(t, ign->tunnels_r_l[h0 ^ h1]) {
129 		if (!ipv6_addr_equal(local, &t->parms.laddr) ||
130 		    !ipv6_addr_equal(remote, &t->parms.raddr) ||
131 		    key != t->parms.i_key ||
132 		    !(t->dev->flags & IFF_UP))
133 			continue;
134 
135 		if (t->dev->type != ARPHRD_IP6GRE &&
136 		    t->dev->type != dev_type)
137 			continue;
138 
139 		score = 0;
140 		if (t->parms.link != link)
141 			score |= 1;
142 		if (t->dev->type != dev_type)
143 			score |= 2;
144 		if (score == 0)
145 			return t;
146 
147 		if (score < cand_score) {
148 			cand = t;
149 			cand_score = score;
150 		}
151 	}
152 
153 	for_each_ip_tunnel_rcu(t, ign->tunnels_r[h0 ^ h1]) {
154 		if (!ipv6_addr_equal(remote, &t->parms.raddr) ||
155 		    key != t->parms.i_key ||
156 		    !(t->dev->flags & IFF_UP))
157 			continue;
158 
159 		if (t->dev->type != ARPHRD_IP6GRE &&
160 		    t->dev->type != dev_type)
161 			continue;
162 
163 		score = 0;
164 		if (t->parms.link != link)
165 			score |= 1;
166 		if (t->dev->type != dev_type)
167 			score |= 2;
168 		if (score == 0)
169 			return t;
170 
171 		if (score < cand_score) {
172 			cand = t;
173 			cand_score = score;
174 		}
175 	}
176 
177 	for_each_ip_tunnel_rcu(t, ign->tunnels_l[h1]) {
178 		if ((!ipv6_addr_equal(local, &t->parms.laddr) &&
179 			  (!ipv6_addr_equal(local, &t->parms.raddr) ||
180 				 !ipv6_addr_is_multicast(local))) ||
181 		    key != t->parms.i_key ||
182 		    !(t->dev->flags & IFF_UP))
183 			continue;
184 
185 		if (t->dev->type != ARPHRD_IP6GRE &&
186 		    t->dev->type != dev_type)
187 			continue;
188 
189 		score = 0;
190 		if (t->parms.link != link)
191 			score |= 1;
192 		if (t->dev->type != dev_type)
193 			score |= 2;
194 		if (score == 0)
195 			return t;
196 
197 		if (score < cand_score) {
198 			cand = t;
199 			cand_score = score;
200 		}
201 	}
202 
203 	for_each_ip_tunnel_rcu(t, ign->tunnels_wc[h1]) {
204 		if (t->parms.i_key != key ||
205 		    !(t->dev->flags & IFF_UP))
206 			continue;
207 
208 		if (t->dev->type != ARPHRD_IP6GRE &&
209 		    t->dev->type != dev_type)
210 			continue;
211 
212 		score = 0;
213 		if (t->parms.link != link)
214 			score |= 1;
215 		if (t->dev->type != dev_type)
216 			score |= 2;
217 		if (score == 0)
218 			return t;
219 
220 		if (score < cand_score) {
221 			cand = t;
222 			cand_score = score;
223 		}
224 	}
225 
226 	if (cand)
227 		return cand;
228 
229 	dev = ign->fb_tunnel_dev;
230 	if (dev->flags & IFF_UP)
231 		return netdev_priv(dev);
232 
233 	return NULL;
234 }
235 
236 static struct ip6_tnl __rcu **__ip6gre_bucket(struct ip6gre_net *ign,
237 		const struct __ip6_tnl_parm *p)
238 {
239 	const struct in6_addr *remote = &p->raddr;
240 	const struct in6_addr *local = &p->laddr;
241 	unsigned int h = HASH_KEY(p->i_key);
242 	int prio = 0;
243 
244 	if (!ipv6_addr_any(local))
245 		prio |= 1;
246 	if (!ipv6_addr_any(remote) && !ipv6_addr_is_multicast(remote)) {
247 		prio |= 2;
248 		h ^= HASH_ADDR(remote);
249 	}
250 
251 	return &ign->tunnels[prio][h];
252 }
253 
254 static inline struct ip6_tnl __rcu **ip6gre_bucket(struct ip6gre_net *ign,
255 		const struct ip6_tnl *t)
256 {
257 	return __ip6gre_bucket(ign, &t->parms);
258 }
259 
260 static void ip6gre_tunnel_link(struct ip6gre_net *ign, struct ip6_tnl *t)
261 {
262 	struct ip6_tnl __rcu **tp = ip6gre_bucket(ign, t);
263 
264 	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
265 	rcu_assign_pointer(*tp, t);
266 }
267 
268 static void ip6gre_tunnel_unlink(struct ip6gre_net *ign, struct ip6_tnl *t)
269 {
270 	struct ip6_tnl __rcu **tp;
271 	struct ip6_tnl *iter;
272 
273 	for (tp = ip6gre_bucket(ign, t);
274 	     (iter = rtnl_dereference(*tp)) != NULL;
275 	     tp = &iter->next) {
276 		if (t == iter) {
277 			rcu_assign_pointer(*tp, t->next);
278 			break;
279 		}
280 	}
281 }
282 
283 static struct ip6_tnl *ip6gre_tunnel_find(struct net *net,
284 					   const struct __ip6_tnl_parm *parms,
285 					   int type)
286 {
287 	const struct in6_addr *remote = &parms->raddr;
288 	const struct in6_addr *local = &parms->laddr;
289 	__be32 key = parms->i_key;
290 	int link = parms->link;
291 	struct ip6_tnl *t;
292 	struct ip6_tnl __rcu **tp;
293 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
294 
295 	for (tp = __ip6gre_bucket(ign, parms);
296 	     (t = rtnl_dereference(*tp)) != NULL;
297 	     tp = &t->next)
298 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
299 		    ipv6_addr_equal(remote, &t->parms.raddr) &&
300 		    key == t->parms.i_key &&
301 		    link == t->parms.link &&
302 		    type == t->dev->type)
303 			break;
304 
305 	return t;
306 }
307 
308 static struct ip6_tnl *ip6gre_tunnel_locate(struct net *net,
309 		const struct __ip6_tnl_parm *parms, int create)
310 {
311 	struct ip6_tnl *t, *nt;
312 	struct net_device *dev;
313 	char name[IFNAMSIZ];
314 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
315 
316 	t = ip6gre_tunnel_find(net, parms, ARPHRD_IP6GRE);
317 	if (t && create)
318 		return NULL;
319 	if (t || !create)
320 		return t;
321 
322 	if (parms->name[0])
323 		strlcpy(name, parms->name, IFNAMSIZ);
324 	else
325 		strcpy(name, "ip6gre%d");
326 
327 	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
328 			   ip6gre_tunnel_setup);
329 	if (!dev)
330 		return NULL;
331 
332 	dev_net_set(dev, net);
333 
334 	nt = netdev_priv(dev);
335 	nt->parms = *parms;
336 	dev->rtnl_link_ops = &ip6gre_link_ops;
337 
338 	nt->dev = dev;
339 	nt->net = dev_net(dev);
340 	ip6gre_tnl_link_config(nt, 1);
341 
342 	if (register_netdevice(dev) < 0)
343 		goto failed_free;
344 
345 	/* Can use a lockless transmit, unless we generate output sequences */
346 	if (!(nt->parms.o_flags & GRE_SEQ))
347 		dev->features |= NETIF_F_LLTX;
348 
349 	dev_hold(dev);
350 	ip6gre_tunnel_link(ign, nt);
351 	return nt;
352 
353 failed_free:
354 	free_netdev(dev);
355 	return NULL;
356 }
357 
358 static void ip6gre_tunnel_uninit(struct net_device *dev)
359 {
360 	struct ip6_tnl *t = netdev_priv(dev);
361 	struct ip6gre_net *ign = net_generic(t->net, ip6gre_net_id);
362 
363 	ip6gre_tunnel_unlink(ign, t);
364 	ip6_tnl_dst_reset(t);
365 	dev_put(dev);
366 }
367 
368 
369 static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
370 		u8 type, u8 code, int offset, __be32 info)
371 {
372 	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)skb->data;
373 	__be16 *p = (__be16 *)(skb->data + offset);
374 	int grehlen = offset + 4;
375 	struct ip6_tnl *t;
376 	__be16 flags;
377 
378 	flags = p[0];
379 	if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
380 		if (flags&(GRE_VERSION|GRE_ROUTING))
381 			return;
382 		if (flags&GRE_KEY) {
383 			grehlen += 4;
384 			if (flags&GRE_CSUM)
385 				grehlen += 4;
386 		}
387 	}
388 
389 	/* If only 8 bytes returned, keyed message will be dropped here */
390 	if (!pskb_may_pull(skb, grehlen))
391 		return;
392 	ipv6h = (const struct ipv6hdr *)skb->data;
393 	p = (__be16 *)(skb->data + offset);
394 
395 	t = ip6gre_tunnel_lookup(skb->dev, &ipv6h->daddr, &ipv6h->saddr,
396 				flags & GRE_KEY ?
397 				*(((__be32 *)p) + (grehlen / 4) - 1) : 0,
398 				p[1]);
399 	if (!t)
400 		return;
401 
402 	switch (type) {
403 		__u32 teli;
404 		struct ipv6_tlv_tnl_enc_lim *tel;
405 		__u32 mtu;
406 	case ICMPV6_DEST_UNREACH:
407 		net_warn_ratelimited("%s: Path to destination invalid or inactive!\n",
408 				     t->parms.name);
409 		break;
410 	case ICMPV6_TIME_EXCEED:
411 		if (code == ICMPV6_EXC_HOPLIMIT) {
412 			net_warn_ratelimited("%s: Too small hop limit or routing loop in tunnel!\n",
413 					     t->parms.name);
414 		}
415 		break;
416 	case ICMPV6_PARAMPROB:
417 		teli = 0;
418 		if (code == ICMPV6_HDR_FIELD)
419 			teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);
420 
421 		if (teli && teli == be32_to_cpu(info) - 2) {
422 			tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
423 			if (tel->encap_limit == 0) {
424 				net_warn_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
425 						     t->parms.name);
426 			}
427 		} else {
428 			net_warn_ratelimited("%s: Recipient unable to parse tunneled packet!\n",
429 					     t->parms.name);
430 		}
431 		break;
432 	case ICMPV6_PKT_TOOBIG:
433 		mtu = be32_to_cpu(info) - offset;
434 		if (mtu < IPV6_MIN_MTU)
435 			mtu = IPV6_MIN_MTU;
436 		t->dev->mtu = mtu;
437 		break;
438 	}
439 
440 	if (time_before(jiffies, t->err_time + IP6TUNNEL_ERR_TIMEO))
441 		t->err_count++;
442 	else
443 		t->err_count = 1;
444 	t->err_time = jiffies;
445 }
446 
447 static int ip6gre_rcv(struct sk_buff *skb)
448 {
449 	const struct ipv6hdr *ipv6h;
450 	u8     *h;
451 	__be16    flags;
452 	__sum16   csum = 0;
453 	__be32 key = 0;
454 	u32    seqno = 0;
455 	struct ip6_tnl *tunnel;
456 	int    offset = 4;
457 	__be16 gre_proto;
458 	int err;
459 
460 	if (!pskb_may_pull(skb, sizeof(struct in6_addr)))
461 		goto drop;
462 
463 	ipv6h = ipv6_hdr(skb);
464 	h = skb->data;
465 	flags = *(__be16 *)h;
466 
467 	if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
468 		/* - Version must be 0.
469 		   - We do not support routing headers.
470 		 */
471 		if (flags&(GRE_VERSION|GRE_ROUTING))
472 			goto drop;
473 
474 		if (flags&GRE_CSUM) {
475 			csum = skb_checksum_simple_validate(skb);
476 			offset += 4;
477 		}
478 		if (flags&GRE_KEY) {
479 			key = *(__be32 *)(h + offset);
480 			offset += 4;
481 		}
482 		if (flags&GRE_SEQ) {
483 			seqno = ntohl(*(__be32 *)(h + offset));
484 			offset += 4;
485 		}
486 	}
487 
488 	gre_proto = *(__be16 *)(h + 2);
489 
490 	tunnel = ip6gre_tunnel_lookup(skb->dev,
491 					  &ipv6h->saddr, &ipv6h->daddr, key,
492 					  gre_proto);
493 	if (tunnel) {
494 		struct pcpu_sw_netstats *tstats;
495 
496 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
497 			goto drop;
498 
499 		if (!ip6_tnl_rcv_ctl(tunnel, &ipv6h->daddr, &ipv6h->saddr)) {
500 			tunnel->dev->stats.rx_dropped++;
501 			goto drop;
502 		}
503 
504 		skb->protocol = gre_proto;
505 		/* WCCP version 1 and 2 protocol decoding.
506 		 * - Change protocol to IPv6
507 		 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
508 		 */
509 		if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
510 			skb->protocol = htons(ETH_P_IPV6);
511 			if ((*(h + offset) & 0xF0) != 0x40)
512 				offset += 4;
513 		}
514 
515 		skb->mac_header = skb->network_header;
516 		__pskb_pull(skb, offset);
517 		skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
518 
519 		if (((flags&GRE_CSUM) && csum) ||
520 		    (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
521 			tunnel->dev->stats.rx_crc_errors++;
522 			tunnel->dev->stats.rx_errors++;
523 			goto drop;
524 		}
525 		if (tunnel->parms.i_flags&GRE_SEQ) {
526 			if (!(flags&GRE_SEQ) ||
527 			    (tunnel->i_seqno &&
528 					(s32)(seqno - tunnel->i_seqno) < 0)) {
529 				tunnel->dev->stats.rx_fifo_errors++;
530 				tunnel->dev->stats.rx_errors++;
531 				goto drop;
532 			}
533 			tunnel->i_seqno = seqno + 1;
534 		}
535 
536 		/* Warning: All skb pointers will be invalidated! */
537 		if (tunnel->dev->type == ARPHRD_ETHER) {
538 			if (!pskb_may_pull(skb, ETH_HLEN)) {
539 				tunnel->dev->stats.rx_length_errors++;
540 				tunnel->dev->stats.rx_errors++;
541 				goto drop;
542 			}
543 
544 			ipv6h = ipv6_hdr(skb);
545 			skb->protocol = eth_type_trans(skb, tunnel->dev);
546 			skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
547 		}
548 
549 		__skb_tunnel_rx(skb, tunnel->dev, tunnel->net);
550 
551 		skb_reset_network_header(skb);
552 
553 		err = IP6_ECN_decapsulate(ipv6h, skb);
554 		if (unlikely(err)) {
555 			if (log_ecn_error)
556 				net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
557 						     &ipv6h->saddr,
558 						     ipv6_get_dsfield(ipv6h));
559 			if (err > 1) {
560 				++tunnel->dev->stats.rx_frame_errors;
561 				++tunnel->dev->stats.rx_errors;
562 				goto drop;
563 			}
564 		}
565 
566 		tstats = this_cpu_ptr(tunnel->dev->tstats);
567 		u64_stats_update_begin(&tstats->syncp);
568 		tstats->rx_packets++;
569 		tstats->rx_bytes += skb->len;
570 		u64_stats_update_end(&tstats->syncp);
571 
572 		netif_rx(skb);
573 
574 		return 0;
575 	}
576 	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
577 
578 drop:
579 	kfree_skb(skb);
580 	return 0;
581 }
582 
583 struct ipv6_tel_txoption {
584 	struct ipv6_txoptions ops;
585 	__u8 dst_opt[8];
586 };
587 
588 static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
589 {
590 	memset(opt, 0, sizeof(struct ipv6_tel_txoption));
591 
592 	opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
593 	opt->dst_opt[3] = 1;
594 	opt->dst_opt[4] = encap_limit;
595 	opt->dst_opt[5] = IPV6_TLV_PADN;
596 	opt->dst_opt[6] = 1;
597 
598 	opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
599 	opt->ops.opt_nflen = 8;
600 }
601 
602 static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
603 			 struct net_device *dev,
604 			 __u8 dsfield,
605 			 struct flowi6 *fl6,
606 			 int encap_limit,
607 			 __u32 *pmtu)
608 {
609 	struct ip6_tnl *tunnel = netdev_priv(dev);
610 	struct net *net = tunnel->net;
611 	struct net_device *tdev;    /* Device to other host */
612 	struct ipv6hdr  *ipv6h;     /* Our new IP header */
613 	unsigned int max_headroom = 0; /* The extra header space needed */
614 	int    gre_hlen;
615 	struct ipv6_tel_txoption opt;
616 	int    mtu;
617 	struct dst_entry *dst = NULL, *ndst = NULL;
618 	struct net_device_stats *stats = &tunnel->dev->stats;
619 	int err = -1;
620 	u8 proto;
621 	struct sk_buff *new_skb;
622 	__be16 protocol;
623 
624 	if (dev->type == ARPHRD_ETHER)
625 		IPCB(skb)->flags = 0;
626 
627 	if (dev->header_ops && dev->type == ARPHRD_IP6GRE) {
628 		gre_hlen = 0;
629 		ipv6h = (struct ipv6hdr *)skb->data;
630 		fl6->daddr = ipv6h->daddr;
631 	} else {
632 		gre_hlen = tunnel->hlen;
633 		fl6->daddr = tunnel->parms.raddr;
634 	}
635 
636 	if (!fl6->flowi6_mark)
637 		dst = ip6_tnl_dst_check(tunnel);
638 
639 	if (!dst) {
640 		ndst = ip6_route_output(net, NULL, fl6);
641 
642 		if (ndst->error)
643 			goto tx_err_link_failure;
644 		ndst = xfrm_lookup(net, ndst, flowi6_to_flowi(fl6), NULL, 0);
645 		if (IS_ERR(ndst)) {
646 			err = PTR_ERR(ndst);
647 			ndst = NULL;
648 			goto tx_err_link_failure;
649 		}
650 		dst = ndst;
651 	}
652 
653 	tdev = dst->dev;
654 
655 	if (tdev == dev) {
656 		stats->collisions++;
657 		net_warn_ratelimited("%s: Local routing loop detected!\n",
658 				     tunnel->parms.name);
659 		goto tx_err_dst_release;
660 	}
661 
662 	mtu = dst_mtu(dst) - sizeof(*ipv6h);
663 	if (encap_limit >= 0) {
664 		max_headroom += 8;
665 		mtu -= 8;
666 	}
667 	if (mtu < IPV6_MIN_MTU)
668 		mtu = IPV6_MIN_MTU;
669 	if (skb_dst(skb))
670 		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
671 	if (skb->len > mtu) {
672 		*pmtu = mtu;
673 		err = -EMSGSIZE;
674 		goto tx_err_dst_release;
675 	}
676 
677 	if (tunnel->err_count > 0) {
678 		if (time_before(jiffies,
679 				tunnel->err_time + IP6TUNNEL_ERR_TIMEO)) {
680 			tunnel->err_count--;
681 
682 			dst_link_failure(skb);
683 		} else
684 			tunnel->err_count = 0;
685 	}
686 
687 	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
688 
689 	max_headroom += LL_RESERVED_SPACE(tdev) + gre_hlen + dst->header_len;
690 
691 	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
692 	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
693 		new_skb = skb_realloc_headroom(skb, max_headroom);
694 		if (max_headroom > dev->needed_headroom)
695 			dev->needed_headroom = max_headroom;
696 		if (!new_skb)
697 			goto tx_err_dst_release;
698 
699 		if (skb->sk)
700 			skb_set_owner_w(new_skb, skb->sk);
701 		consume_skb(skb);
702 		skb = new_skb;
703 	}
704 
705 	if (fl6->flowi6_mark) {
706 		skb_dst_set(skb, dst);
707 		ndst = NULL;
708 	} else {
709 		skb_dst_set_noref(skb, dst);
710 	}
711 
712 	proto = NEXTHDR_GRE;
713 	if (encap_limit >= 0) {
714 		init_tel_txopt(&opt, encap_limit);
715 		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
716 	}
717 
718 	if (likely(!skb->encapsulation)) {
719 		skb_reset_inner_headers(skb);
720 		skb->encapsulation = 1;
721 	}
722 
723 	skb_push(skb, gre_hlen);
724 	skb_reset_network_header(skb);
725 	skb_set_transport_header(skb, sizeof(*ipv6h));
726 
727 	/*
728 	 *	Push down and install the IP header.
729 	 */
730 	ipv6h = ipv6_hdr(skb);
731 	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
732 		     ip6_make_flowlabel(net, skb, fl6->flowlabel, true, fl6));
733 	ipv6h->hop_limit = tunnel->parms.hop_limit;
734 	ipv6h->nexthdr = proto;
735 	ipv6h->saddr = fl6->saddr;
736 	ipv6h->daddr = fl6->daddr;
737 
738 	((__be16 *)(ipv6h + 1))[0] = tunnel->parms.o_flags;
739 	protocol = (dev->type == ARPHRD_ETHER) ?
740 		    htons(ETH_P_TEB) : skb->protocol;
741 	((__be16 *)(ipv6h + 1))[1] = protocol;
742 
743 	if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
744 		__be32 *ptr = (__be32 *)(((u8 *)ipv6h) + tunnel->hlen - 4);
745 
746 		if (tunnel->parms.o_flags&GRE_SEQ) {
747 			++tunnel->o_seqno;
748 			*ptr = htonl(tunnel->o_seqno);
749 			ptr--;
750 		}
751 		if (tunnel->parms.o_flags&GRE_KEY) {
752 			*ptr = tunnel->parms.o_key;
753 			ptr--;
754 		}
755 		if (tunnel->parms.o_flags&GRE_CSUM) {
756 			*ptr = 0;
757 			*(__sum16 *)ptr = ip_compute_csum((void *)(ipv6h+1),
758 				skb->len - sizeof(struct ipv6hdr));
759 		}
760 	}
761 
762 	skb_set_inner_protocol(skb, protocol);
763 
764 	ip6tunnel_xmit(NULL, skb, dev);
765 	if (ndst)
766 		ip6_tnl_dst_store(tunnel, ndst);
767 	return 0;
768 tx_err_link_failure:
769 	stats->tx_carrier_errors++;
770 	dst_link_failure(skb);
771 tx_err_dst_release:
772 	dst_release(ndst);
773 	return err;
774 }
775 
776 static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
777 {
778 	struct ip6_tnl *t = netdev_priv(dev);
779 	const struct iphdr  *iph = ip_hdr(skb);
780 	int encap_limit = -1;
781 	struct flowi6 fl6;
782 	__u8 dsfield;
783 	__u32 mtu;
784 	int err;
785 
786 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
787 		encap_limit = t->parms.encap_limit;
788 
789 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
790 	fl6.flowi6_proto = IPPROTO_GRE;
791 
792 	dsfield = ipv4_get_dsfield(iph);
793 
794 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
795 		fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
796 					  & IPV6_TCLASS_MASK;
797 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
798 		fl6.flowi6_mark = skb->mark;
799 
800 	err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
801 	if (err != 0) {
802 		/* XXX: send ICMP error even if DF is not set. */
803 		if (err == -EMSGSIZE)
804 			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
805 				  htonl(mtu));
806 		return -1;
807 	}
808 
809 	return 0;
810 }
811 
812 static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev)
813 {
814 	struct ip6_tnl *t = netdev_priv(dev);
815 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
816 	int encap_limit = -1;
817 	__u16 offset;
818 	struct flowi6 fl6;
819 	__u8 dsfield;
820 	__u32 mtu;
821 	int err;
822 
823 	if (ipv6_addr_equal(&t->parms.raddr, &ipv6h->saddr))
824 		return -1;
825 
826 	offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
827 	if (offset > 0) {
828 		struct ipv6_tlv_tnl_enc_lim *tel;
829 		tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
830 		if (tel->encap_limit == 0) {
831 			icmpv6_send(skb, ICMPV6_PARAMPROB,
832 				    ICMPV6_HDR_FIELD, offset + 2);
833 			return -1;
834 		}
835 		encap_limit = tel->encap_limit - 1;
836 	} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
837 		encap_limit = t->parms.encap_limit;
838 
839 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
840 	fl6.flowi6_proto = IPPROTO_GRE;
841 
842 	dsfield = ipv6_get_dsfield(ipv6h);
843 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
844 		fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
845 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
846 		fl6.flowlabel |= ip6_flowlabel(ipv6h);
847 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
848 		fl6.flowi6_mark = skb->mark;
849 
850 	err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
851 	if (err != 0) {
852 		if (err == -EMSGSIZE)
853 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
854 		return -1;
855 	}
856 
857 	return 0;
858 }
859 
860 /**
861  * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
862  *   @t: the outgoing tunnel device
863  *   @hdr: IPv6 header from the incoming packet
864  *
865  * Description:
866  *   Avoid trivial tunneling loop by checking that tunnel exit-point
867  *   doesn't match source of incoming packet.
868  *
869  * Return:
870  *   1 if conflict,
871  *   0 else
872  **/
873 
874 static inline bool ip6gre_tnl_addr_conflict(const struct ip6_tnl *t,
875 	const struct ipv6hdr *hdr)
876 {
877 	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
878 }
879 
880 static int ip6gre_xmit_other(struct sk_buff *skb, struct net_device *dev)
881 {
882 	struct ip6_tnl *t = netdev_priv(dev);
883 	int encap_limit = -1;
884 	struct flowi6 fl6;
885 	__u32 mtu;
886 	int err;
887 
888 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
889 		encap_limit = t->parms.encap_limit;
890 
891 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
892 	fl6.flowi6_proto = skb->protocol;
893 
894 	err = ip6gre_xmit2(skb, dev, 0, &fl6, encap_limit, &mtu);
895 
896 	return err;
897 }
898 
899 static netdev_tx_t ip6gre_tunnel_xmit(struct sk_buff *skb,
900 	struct net_device *dev)
901 {
902 	struct ip6_tnl *t = netdev_priv(dev);
903 	struct net_device_stats *stats = &t->dev->stats;
904 	int ret;
905 
906 	if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))
907 		goto tx_err;
908 
909 	switch (skb->protocol) {
910 	case htons(ETH_P_IP):
911 		ret = ip6gre_xmit_ipv4(skb, dev);
912 		break;
913 	case htons(ETH_P_IPV6):
914 		ret = ip6gre_xmit_ipv6(skb, dev);
915 		break;
916 	default:
917 		ret = ip6gre_xmit_other(skb, dev);
918 		break;
919 	}
920 
921 	if (ret < 0)
922 		goto tx_err;
923 
924 	return NETDEV_TX_OK;
925 
926 tx_err:
927 	stats->tx_errors++;
928 	stats->tx_dropped++;
929 	kfree_skb(skb);
930 	return NETDEV_TX_OK;
931 }
932 
933 static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu)
934 {
935 	struct net_device *dev = t->dev;
936 	struct __ip6_tnl_parm *p = &t->parms;
937 	struct flowi6 *fl6 = &t->fl.u.ip6;
938 	int addend = sizeof(struct ipv6hdr) + 4;
939 
940 	if (dev->type != ARPHRD_ETHER) {
941 		memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
942 		memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
943 	}
944 
945 	/* Set up flowi template */
946 	fl6->saddr = p->laddr;
947 	fl6->daddr = p->raddr;
948 	fl6->flowi6_oif = p->link;
949 	fl6->flowlabel = 0;
950 
951 	if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
952 		fl6->flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
953 	if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
954 		fl6->flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
955 
956 	p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV|IP6_TNL_F_CAP_PER_PACKET);
957 	p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);
958 
959 	if (p->flags&IP6_TNL_F_CAP_XMIT &&
960 			p->flags&IP6_TNL_F_CAP_RCV && dev->type != ARPHRD_ETHER)
961 		dev->flags |= IFF_POINTOPOINT;
962 	else
963 		dev->flags &= ~IFF_POINTOPOINT;
964 
965 	/* Precalculate GRE options length */
966 	if (t->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) {
967 		if (t->parms.o_flags&GRE_CSUM)
968 			addend += 4;
969 		if (t->parms.o_flags&GRE_KEY)
970 			addend += 4;
971 		if (t->parms.o_flags&GRE_SEQ)
972 			addend += 4;
973 	}
974 	t->hlen = addend;
975 
976 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
977 		int strict = (ipv6_addr_type(&p->raddr) &
978 			      (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
979 
980 		struct rt6_info *rt = rt6_lookup(t->net,
981 						 &p->raddr, &p->laddr,
982 						 p->link, strict);
983 
984 		if (!rt)
985 			return;
986 
987 		if (rt->dst.dev) {
988 			dev->hard_header_len = rt->dst.dev->hard_header_len + addend;
989 
990 			if (set_mtu) {
991 				dev->mtu = rt->dst.dev->mtu - addend;
992 				if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
993 					dev->mtu -= 8;
994 
995 				if (dev->mtu < IPV6_MIN_MTU)
996 					dev->mtu = IPV6_MIN_MTU;
997 			}
998 		}
999 		ip6_rt_put(rt);
1000 	}
1001 }
1002 
1003 static int ip6gre_tnl_change(struct ip6_tnl *t,
1004 	const struct __ip6_tnl_parm *p, int set_mtu)
1005 {
1006 	t->parms.laddr = p->laddr;
1007 	t->parms.raddr = p->raddr;
1008 	t->parms.flags = p->flags;
1009 	t->parms.hop_limit = p->hop_limit;
1010 	t->parms.encap_limit = p->encap_limit;
1011 	t->parms.flowinfo = p->flowinfo;
1012 	t->parms.link = p->link;
1013 	t->parms.proto = p->proto;
1014 	t->parms.i_key = p->i_key;
1015 	t->parms.o_key = p->o_key;
1016 	t->parms.i_flags = p->i_flags;
1017 	t->parms.o_flags = p->o_flags;
1018 	ip6_tnl_dst_reset(t);
1019 	ip6gre_tnl_link_config(t, set_mtu);
1020 	return 0;
1021 }
1022 
1023 static void ip6gre_tnl_parm_from_user(struct __ip6_tnl_parm *p,
1024 	const struct ip6_tnl_parm2 *u)
1025 {
1026 	p->laddr = u->laddr;
1027 	p->raddr = u->raddr;
1028 	p->flags = u->flags;
1029 	p->hop_limit = u->hop_limit;
1030 	p->encap_limit = u->encap_limit;
1031 	p->flowinfo = u->flowinfo;
1032 	p->link = u->link;
1033 	p->i_key = u->i_key;
1034 	p->o_key = u->o_key;
1035 	p->i_flags = u->i_flags;
1036 	p->o_flags = u->o_flags;
1037 	memcpy(p->name, u->name, sizeof(u->name));
1038 }
1039 
1040 static void ip6gre_tnl_parm_to_user(struct ip6_tnl_parm2 *u,
1041 	const struct __ip6_tnl_parm *p)
1042 {
1043 	u->proto = IPPROTO_GRE;
1044 	u->laddr = p->laddr;
1045 	u->raddr = p->raddr;
1046 	u->flags = p->flags;
1047 	u->hop_limit = p->hop_limit;
1048 	u->encap_limit = p->encap_limit;
1049 	u->flowinfo = p->flowinfo;
1050 	u->link = p->link;
1051 	u->i_key = p->i_key;
1052 	u->o_key = p->o_key;
1053 	u->i_flags = p->i_flags;
1054 	u->o_flags = p->o_flags;
1055 	memcpy(u->name, p->name, sizeof(u->name));
1056 }
1057 
1058 static int ip6gre_tunnel_ioctl(struct net_device *dev,
1059 	struct ifreq *ifr, int cmd)
1060 {
1061 	int err = 0;
1062 	struct ip6_tnl_parm2 p;
1063 	struct __ip6_tnl_parm p1;
1064 	struct ip6_tnl *t = netdev_priv(dev);
1065 	struct net *net = t->net;
1066 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
1067 
1068 	switch (cmd) {
1069 	case SIOCGETTUNNEL:
1070 		if (dev == ign->fb_tunnel_dev) {
1071 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1072 				err = -EFAULT;
1073 				break;
1074 			}
1075 			ip6gre_tnl_parm_from_user(&p1, &p);
1076 			t = ip6gre_tunnel_locate(net, &p1, 0);
1077 			if (!t)
1078 				t = netdev_priv(dev);
1079 		}
1080 		memset(&p, 0, sizeof(p));
1081 		ip6gre_tnl_parm_to_user(&p, &t->parms);
1082 		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1083 			err = -EFAULT;
1084 		break;
1085 
1086 	case SIOCADDTUNNEL:
1087 	case SIOCCHGTUNNEL:
1088 		err = -EPERM;
1089 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1090 			goto done;
1091 
1092 		err = -EFAULT;
1093 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1094 			goto done;
1095 
1096 		err = -EINVAL;
1097 		if ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING))
1098 			goto done;
1099 
1100 		if (!(p.i_flags&GRE_KEY))
1101 			p.i_key = 0;
1102 		if (!(p.o_flags&GRE_KEY))
1103 			p.o_key = 0;
1104 
1105 		ip6gre_tnl_parm_from_user(&p1, &p);
1106 		t = ip6gre_tunnel_locate(net, &p1, cmd == SIOCADDTUNNEL);
1107 
1108 		if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1109 			if (t) {
1110 				if (t->dev != dev) {
1111 					err = -EEXIST;
1112 					break;
1113 				}
1114 			} else {
1115 				t = netdev_priv(dev);
1116 
1117 				ip6gre_tunnel_unlink(ign, t);
1118 				synchronize_net();
1119 				ip6gre_tnl_change(t, &p1, 1);
1120 				ip6gre_tunnel_link(ign, t);
1121 				netdev_state_change(dev);
1122 			}
1123 		}
1124 
1125 		if (t) {
1126 			err = 0;
1127 
1128 			memset(&p, 0, sizeof(p));
1129 			ip6gre_tnl_parm_to_user(&p, &t->parms);
1130 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1131 				err = -EFAULT;
1132 		} else
1133 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1134 		break;
1135 
1136 	case SIOCDELTUNNEL:
1137 		err = -EPERM;
1138 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1139 			goto done;
1140 
1141 		if (dev == ign->fb_tunnel_dev) {
1142 			err = -EFAULT;
1143 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1144 				goto done;
1145 			err = -ENOENT;
1146 			ip6gre_tnl_parm_from_user(&p1, &p);
1147 			t = ip6gre_tunnel_locate(net, &p1, 0);
1148 			if (!t)
1149 				goto done;
1150 			err = -EPERM;
1151 			if (t == netdev_priv(ign->fb_tunnel_dev))
1152 				goto done;
1153 			dev = t->dev;
1154 		}
1155 		unregister_netdevice(dev);
1156 		err = 0;
1157 		break;
1158 
1159 	default:
1160 		err = -EINVAL;
1161 	}
1162 
1163 done:
1164 	return err;
1165 }
1166 
1167 static int ip6gre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1168 {
1169 	if (new_mtu < 68 ||
1170 	    new_mtu > 0xFFF8 - dev->hard_header_len)
1171 		return -EINVAL;
1172 	dev->mtu = new_mtu;
1173 	return 0;
1174 }
1175 
1176 static int ip6gre_header(struct sk_buff *skb, struct net_device *dev,
1177 			unsigned short type,
1178 			const void *daddr, const void *saddr, unsigned int len)
1179 {
1180 	struct ip6_tnl *t = netdev_priv(dev);
1181 	struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb_push(skb, t->hlen);
1182 	__be16 *p = (__be16 *)(ipv6h+1);
1183 
1184 	ip6_flow_hdr(ipv6h, 0,
1185 		     ip6_make_flowlabel(dev_net(dev), skb,
1186 					t->fl.u.ip6.flowlabel, true,
1187 					&t->fl.u.ip6));
1188 	ipv6h->hop_limit = t->parms.hop_limit;
1189 	ipv6h->nexthdr = NEXTHDR_GRE;
1190 	ipv6h->saddr = t->parms.laddr;
1191 	ipv6h->daddr = t->parms.raddr;
1192 
1193 	p[0]		= t->parms.o_flags;
1194 	p[1]		= htons(type);
1195 
1196 	/*
1197 	 *	Set the source hardware address.
1198 	 */
1199 
1200 	if (saddr)
1201 		memcpy(&ipv6h->saddr, saddr, sizeof(struct in6_addr));
1202 	if (daddr)
1203 		memcpy(&ipv6h->daddr, daddr, sizeof(struct in6_addr));
1204 	if (!ipv6_addr_any(&ipv6h->daddr))
1205 		return t->hlen;
1206 
1207 	return -t->hlen;
1208 }
1209 
1210 static const struct header_ops ip6gre_header_ops = {
1211 	.create	= ip6gre_header,
1212 };
1213 
1214 static const struct net_device_ops ip6gre_netdev_ops = {
1215 	.ndo_init		= ip6gre_tunnel_init,
1216 	.ndo_uninit		= ip6gre_tunnel_uninit,
1217 	.ndo_start_xmit		= ip6gre_tunnel_xmit,
1218 	.ndo_do_ioctl		= ip6gre_tunnel_ioctl,
1219 	.ndo_change_mtu		= ip6gre_tunnel_change_mtu,
1220 	.ndo_get_stats64	= ip_tunnel_get_stats64,
1221 	.ndo_get_iflink		= ip6_tnl_get_iflink,
1222 };
1223 
1224 static void ip6gre_dev_free(struct net_device *dev)
1225 {
1226 	free_percpu(dev->tstats);
1227 	free_netdev(dev);
1228 }
1229 
1230 static void ip6gre_tunnel_setup(struct net_device *dev)
1231 {
1232 	struct ip6_tnl *t;
1233 
1234 	dev->netdev_ops = &ip6gre_netdev_ops;
1235 	dev->destructor = ip6gre_dev_free;
1236 
1237 	dev->type = ARPHRD_IP6GRE;
1238 	dev->hard_header_len = LL_MAX_HEADER + sizeof(struct ipv6hdr) + 4;
1239 	dev->mtu = ETH_DATA_LEN - sizeof(struct ipv6hdr) - 4;
1240 	t = netdev_priv(dev);
1241 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1242 		dev->mtu -= 8;
1243 	dev->flags |= IFF_NOARP;
1244 	dev->addr_len = sizeof(struct in6_addr);
1245 	netif_keep_dst(dev);
1246 }
1247 
1248 static int ip6gre_tunnel_init(struct net_device *dev)
1249 {
1250 	struct ip6_tnl *tunnel;
1251 
1252 	tunnel = netdev_priv(dev);
1253 
1254 	tunnel->dev = dev;
1255 	tunnel->net = dev_net(dev);
1256 	strcpy(tunnel->parms.name, dev->name);
1257 
1258 	memcpy(dev->dev_addr, &tunnel->parms.laddr, sizeof(struct in6_addr));
1259 	memcpy(dev->broadcast, &tunnel->parms.raddr, sizeof(struct in6_addr));
1260 
1261 	if (ipv6_addr_any(&tunnel->parms.raddr))
1262 		dev->header_ops = &ip6gre_header_ops;
1263 
1264 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1265 	if (!dev->tstats)
1266 		return -ENOMEM;
1267 
1268 	return 0;
1269 }
1270 
1271 static void ip6gre_fb_tunnel_init(struct net_device *dev)
1272 {
1273 	struct ip6_tnl *tunnel = netdev_priv(dev);
1274 
1275 	tunnel->dev = dev;
1276 	tunnel->net = dev_net(dev);
1277 	strcpy(tunnel->parms.name, dev->name);
1278 
1279 	tunnel->hlen		= sizeof(struct ipv6hdr) + 4;
1280 
1281 	dev_hold(dev);
1282 }
1283 
1284 
1285 static struct inet6_protocol ip6gre_protocol __read_mostly = {
1286 	.handler     = ip6gre_rcv,
1287 	.err_handler = ip6gre_err,
1288 	.flags       = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1289 };
1290 
1291 static void ip6gre_destroy_tunnels(struct net *net, struct list_head *head)
1292 {
1293 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
1294 	struct net_device *dev, *aux;
1295 	int prio;
1296 
1297 	for_each_netdev_safe(net, dev, aux)
1298 		if (dev->rtnl_link_ops == &ip6gre_link_ops ||
1299 		    dev->rtnl_link_ops == &ip6gre_tap_ops)
1300 			unregister_netdevice_queue(dev, head);
1301 
1302 	for (prio = 0; prio < 4; prio++) {
1303 		int h;
1304 		for (h = 0; h < HASH_SIZE; h++) {
1305 			struct ip6_tnl *t;
1306 
1307 			t = rtnl_dereference(ign->tunnels[prio][h]);
1308 
1309 			while (t) {
1310 				/* If dev is in the same netns, it has already
1311 				 * been added to the list by the previous loop.
1312 				 */
1313 				if (!net_eq(dev_net(t->dev), net))
1314 					unregister_netdevice_queue(t->dev,
1315 								   head);
1316 				t = rtnl_dereference(t->next);
1317 			}
1318 		}
1319 	}
1320 }
1321 
1322 static int __net_init ip6gre_init_net(struct net *net)
1323 {
1324 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
1325 	int err;
1326 
1327 	ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6gre0",
1328 					  NET_NAME_UNKNOWN,
1329 					  ip6gre_tunnel_setup);
1330 	if (!ign->fb_tunnel_dev) {
1331 		err = -ENOMEM;
1332 		goto err_alloc_dev;
1333 	}
1334 	dev_net_set(ign->fb_tunnel_dev, net);
1335 	/* FB netdevice is special: we have one, and only one per netns.
1336 	 * Allowing to move it to another netns is clearly unsafe.
1337 	 */
1338 	ign->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1339 
1340 
1341 	ip6gre_fb_tunnel_init(ign->fb_tunnel_dev);
1342 	ign->fb_tunnel_dev->rtnl_link_ops = &ip6gre_link_ops;
1343 
1344 	err = register_netdev(ign->fb_tunnel_dev);
1345 	if (err)
1346 		goto err_reg_dev;
1347 
1348 	rcu_assign_pointer(ign->tunnels_wc[0],
1349 			   netdev_priv(ign->fb_tunnel_dev));
1350 	return 0;
1351 
1352 err_reg_dev:
1353 	ip6gre_dev_free(ign->fb_tunnel_dev);
1354 err_alloc_dev:
1355 	return err;
1356 }
1357 
1358 static void __net_exit ip6gre_exit_net(struct net *net)
1359 {
1360 	LIST_HEAD(list);
1361 
1362 	rtnl_lock();
1363 	ip6gre_destroy_tunnels(net, &list);
1364 	unregister_netdevice_many(&list);
1365 	rtnl_unlock();
1366 }
1367 
1368 static struct pernet_operations ip6gre_net_ops = {
1369 	.init = ip6gre_init_net,
1370 	.exit = ip6gre_exit_net,
1371 	.id   = &ip6gre_net_id,
1372 	.size = sizeof(struct ip6gre_net),
1373 };
1374 
1375 static int ip6gre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
1376 {
1377 	__be16 flags;
1378 
1379 	if (!data)
1380 		return 0;
1381 
1382 	flags = 0;
1383 	if (data[IFLA_GRE_IFLAGS])
1384 		flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1385 	if (data[IFLA_GRE_OFLAGS])
1386 		flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1387 	if (flags & (GRE_VERSION|GRE_ROUTING))
1388 		return -EINVAL;
1389 
1390 	return 0;
1391 }
1392 
1393 static int ip6gre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
1394 {
1395 	struct in6_addr daddr;
1396 
1397 	if (tb[IFLA_ADDRESS]) {
1398 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1399 			return -EINVAL;
1400 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1401 			return -EADDRNOTAVAIL;
1402 	}
1403 
1404 	if (!data)
1405 		goto out;
1406 
1407 	if (data[IFLA_GRE_REMOTE]) {
1408 		daddr = nla_get_in6_addr(data[IFLA_GRE_REMOTE]);
1409 		if (ipv6_addr_any(&daddr))
1410 			return -EINVAL;
1411 	}
1412 
1413 out:
1414 	return ip6gre_tunnel_validate(tb, data);
1415 }
1416 
1417 
1418 static void ip6gre_netlink_parms(struct nlattr *data[],
1419 				struct __ip6_tnl_parm *parms)
1420 {
1421 	memset(parms, 0, sizeof(*parms));
1422 
1423 	if (!data)
1424 		return;
1425 
1426 	if (data[IFLA_GRE_LINK])
1427 		parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1428 
1429 	if (data[IFLA_GRE_IFLAGS])
1430 		parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]);
1431 
1432 	if (data[IFLA_GRE_OFLAGS])
1433 		parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]);
1434 
1435 	if (data[IFLA_GRE_IKEY])
1436 		parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1437 
1438 	if (data[IFLA_GRE_OKEY])
1439 		parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1440 
1441 	if (data[IFLA_GRE_LOCAL])
1442 		parms->laddr = nla_get_in6_addr(data[IFLA_GRE_LOCAL]);
1443 
1444 	if (data[IFLA_GRE_REMOTE])
1445 		parms->raddr = nla_get_in6_addr(data[IFLA_GRE_REMOTE]);
1446 
1447 	if (data[IFLA_GRE_TTL])
1448 		parms->hop_limit = nla_get_u8(data[IFLA_GRE_TTL]);
1449 
1450 	if (data[IFLA_GRE_ENCAP_LIMIT])
1451 		parms->encap_limit = nla_get_u8(data[IFLA_GRE_ENCAP_LIMIT]);
1452 
1453 	if (data[IFLA_GRE_FLOWINFO])
1454 		parms->flowinfo = nla_get_u32(data[IFLA_GRE_FLOWINFO]);
1455 
1456 	if (data[IFLA_GRE_FLAGS])
1457 		parms->flags = nla_get_u32(data[IFLA_GRE_FLAGS]);
1458 }
1459 
1460 static int ip6gre_tap_init(struct net_device *dev)
1461 {
1462 	struct ip6_tnl *tunnel;
1463 
1464 	tunnel = netdev_priv(dev);
1465 
1466 	tunnel->dev = dev;
1467 	tunnel->net = dev_net(dev);
1468 	strcpy(tunnel->parms.name, dev->name);
1469 
1470 	ip6gre_tnl_link_config(tunnel, 1);
1471 
1472 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1473 	if (!dev->tstats)
1474 		return -ENOMEM;
1475 
1476 	return 0;
1477 }
1478 
1479 static const struct net_device_ops ip6gre_tap_netdev_ops = {
1480 	.ndo_init = ip6gre_tap_init,
1481 	.ndo_uninit = ip6gre_tunnel_uninit,
1482 	.ndo_start_xmit = ip6gre_tunnel_xmit,
1483 	.ndo_set_mac_address = eth_mac_addr,
1484 	.ndo_validate_addr = eth_validate_addr,
1485 	.ndo_change_mtu = ip6gre_tunnel_change_mtu,
1486 	.ndo_get_stats64 = ip_tunnel_get_stats64,
1487 	.ndo_get_iflink = ip6_tnl_get_iflink,
1488 };
1489 
1490 static void ip6gre_tap_setup(struct net_device *dev)
1491 {
1492 
1493 	ether_setup(dev);
1494 
1495 	dev->netdev_ops = &ip6gre_tap_netdev_ops;
1496 	dev->destructor = ip6gre_dev_free;
1497 
1498 	dev->features |= NETIF_F_NETNS_LOCAL;
1499 }
1500 
1501 static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
1502 	struct nlattr *tb[], struct nlattr *data[])
1503 {
1504 	struct ip6_tnl *nt;
1505 	struct net *net = dev_net(dev);
1506 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
1507 	int err;
1508 
1509 	nt = netdev_priv(dev);
1510 	ip6gre_netlink_parms(data, &nt->parms);
1511 
1512 	if (ip6gre_tunnel_find(net, &nt->parms, dev->type))
1513 		return -EEXIST;
1514 
1515 	if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
1516 		eth_hw_addr_random(dev);
1517 
1518 	nt->dev = dev;
1519 	nt->net = dev_net(dev);
1520 	ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);
1521 
1522 	/* Can use a lockless transmit, unless we generate output sequences */
1523 	if (!(nt->parms.o_flags & GRE_SEQ))
1524 		dev->features |= NETIF_F_LLTX;
1525 
1526 	err = register_netdevice(dev);
1527 	if (err)
1528 		goto out;
1529 
1530 	dev_hold(dev);
1531 	ip6gre_tunnel_link(ign, nt);
1532 
1533 out:
1534 	return err;
1535 }
1536 
1537 static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[],
1538 			    struct nlattr *data[])
1539 {
1540 	struct ip6_tnl *t, *nt = netdev_priv(dev);
1541 	struct net *net = nt->net;
1542 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
1543 	struct __ip6_tnl_parm p;
1544 
1545 	if (dev == ign->fb_tunnel_dev)
1546 		return -EINVAL;
1547 
1548 	ip6gre_netlink_parms(data, &p);
1549 
1550 	t = ip6gre_tunnel_locate(net, &p, 0);
1551 
1552 	if (t) {
1553 		if (t->dev != dev)
1554 			return -EEXIST;
1555 	} else {
1556 		t = nt;
1557 
1558 		ip6gre_tunnel_unlink(ign, t);
1559 		ip6gre_tnl_change(t, &p, !tb[IFLA_MTU]);
1560 		ip6gre_tunnel_link(ign, t);
1561 		netdev_state_change(dev);
1562 	}
1563 
1564 	return 0;
1565 }
1566 
1567 static void ip6gre_dellink(struct net_device *dev, struct list_head *head)
1568 {
1569 	struct net *net = dev_net(dev);
1570 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
1571 
1572 	if (dev != ign->fb_tunnel_dev)
1573 		unregister_netdevice_queue(dev, head);
1574 }
1575 
1576 static size_t ip6gre_get_size(const struct net_device *dev)
1577 {
1578 	return
1579 		/* IFLA_GRE_LINK */
1580 		nla_total_size(4) +
1581 		/* IFLA_GRE_IFLAGS */
1582 		nla_total_size(2) +
1583 		/* IFLA_GRE_OFLAGS */
1584 		nla_total_size(2) +
1585 		/* IFLA_GRE_IKEY */
1586 		nla_total_size(4) +
1587 		/* IFLA_GRE_OKEY */
1588 		nla_total_size(4) +
1589 		/* IFLA_GRE_LOCAL */
1590 		nla_total_size(sizeof(struct in6_addr)) +
1591 		/* IFLA_GRE_REMOTE */
1592 		nla_total_size(sizeof(struct in6_addr)) +
1593 		/* IFLA_GRE_TTL */
1594 		nla_total_size(1) +
1595 		/* IFLA_GRE_TOS */
1596 		nla_total_size(1) +
1597 		/* IFLA_GRE_ENCAP_LIMIT */
1598 		nla_total_size(1) +
1599 		/* IFLA_GRE_FLOWINFO */
1600 		nla_total_size(4) +
1601 		/* IFLA_GRE_FLAGS */
1602 		nla_total_size(4) +
1603 		0;
1604 }
1605 
1606 static int ip6gre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1607 {
1608 	struct ip6_tnl *t = netdev_priv(dev);
1609 	struct __ip6_tnl_parm *p = &t->parms;
1610 
1611 	if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
1612 	    nla_put_be16(skb, IFLA_GRE_IFLAGS, p->i_flags) ||
1613 	    nla_put_be16(skb, IFLA_GRE_OFLAGS, p->o_flags) ||
1614 	    nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
1615 	    nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
1616 	    nla_put_in6_addr(skb, IFLA_GRE_LOCAL, &p->laddr) ||
1617 	    nla_put_in6_addr(skb, IFLA_GRE_REMOTE, &p->raddr) ||
1618 	    nla_put_u8(skb, IFLA_GRE_TTL, p->hop_limit) ||
1619 	    /*nla_put_u8(skb, IFLA_GRE_TOS, t->priority) ||*/
1620 	    nla_put_u8(skb, IFLA_GRE_ENCAP_LIMIT, p->encap_limit) ||
1621 	    nla_put_be32(skb, IFLA_GRE_FLOWINFO, p->flowinfo) ||
1622 	    nla_put_u32(skb, IFLA_GRE_FLAGS, p->flags))
1623 		goto nla_put_failure;
1624 	return 0;
1625 
1626 nla_put_failure:
1627 	return -EMSGSIZE;
1628 }
1629 
1630 static const struct nla_policy ip6gre_policy[IFLA_GRE_MAX + 1] = {
1631 	[IFLA_GRE_LINK]        = { .type = NLA_U32 },
1632 	[IFLA_GRE_IFLAGS]      = { .type = NLA_U16 },
1633 	[IFLA_GRE_OFLAGS]      = { .type = NLA_U16 },
1634 	[IFLA_GRE_IKEY]        = { .type = NLA_U32 },
1635 	[IFLA_GRE_OKEY]        = { .type = NLA_U32 },
1636 	[IFLA_GRE_LOCAL]       = { .len = FIELD_SIZEOF(struct ipv6hdr, saddr) },
1637 	[IFLA_GRE_REMOTE]      = { .len = FIELD_SIZEOF(struct ipv6hdr, daddr) },
1638 	[IFLA_GRE_TTL]         = { .type = NLA_U8 },
1639 	[IFLA_GRE_ENCAP_LIMIT] = { .type = NLA_U8 },
1640 	[IFLA_GRE_FLOWINFO]    = { .type = NLA_U32 },
1641 	[IFLA_GRE_FLAGS]       = { .type = NLA_U32 },
1642 };
1643 
1644 static struct rtnl_link_ops ip6gre_link_ops __read_mostly = {
1645 	.kind		= "ip6gre",
1646 	.maxtype	= IFLA_GRE_MAX,
1647 	.policy		= ip6gre_policy,
1648 	.priv_size	= sizeof(struct ip6_tnl),
1649 	.setup		= ip6gre_tunnel_setup,
1650 	.validate	= ip6gre_tunnel_validate,
1651 	.newlink	= ip6gre_newlink,
1652 	.changelink	= ip6gre_changelink,
1653 	.dellink	= ip6gre_dellink,
1654 	.get_size	= ip6gre_get_size,
1655 	.fill_info	= ip6gre_fill_info,
1656 	.get_link_net	= ip6_tnl_get_link_net,
1657 };
1658 
1659 static struct rtnl_link_ops ip6gre_tap_ops __read_mostly = {
1660 	.kind		= "ip6gretap",
1661 	.maxtype	= IFLA_GRE_MAX,
1662 	.policy		= ip6gre_policy,
1663 	.priv_size	= sizeof(struct ip6_tnl),
1664 	.setup		= ip6gre_tap_setup,
1665 	.validate	= ip6gre_tap_validate,
1666 	.newlink	= ip6gre_newlink,
1667 	.changelink	= ip6gre_changelink,
1668 	.get_size	= ip6gre_get_size,
1669 	.fill_info	= ip6gre_fill_info,
1670 	.get_link_net	= ip6_tnl_get_link_net,
1671 };
1672 
1673 /*
1674  *	And now the modules code and kernel interface.
1675  */
1676 
1677 static int __init ip6gre_init(void)
1678 {
1679 	int err;
1680 
1681 	pr_info("GRE over IPv6 tunneling driver\n");
1682 
1683 	err = register_pernet_device(&ip6gre_net_ops);
1684 	if (err < 0)
1685 		return err;
1686 
1687 	err = inet6_add_protocol(&ip6gre_protocol, IPPROTO_GRE);
1688 	if (err < 0) {
1689 		pr_info("%s: can't add protocol\n", __func__);
1690 		goto add_proto_failed;
1691 	}
1692 
1693 	err = rtnl_link_register(&ip6gre_link_ops);
1694 	if (err < 0)
1695 		goto rtnl_link_failed;
1696 
1697 	err = rtnl_link_register(&ip6gre_tap_ops);
1698 	if (err < 0)
1699 		goto tap_ops_failed;
1700 
1701 out:
1702 	return err;
1703 
1704 tap_ops_failed:
1705 	rtnl_link_unregister(&ip6gre_link_ops);
1706 rtnl_link_failed:
1707 	inet6_del_protocol(&ip6gre_protocol, IPPROTO_GRE);
1708 add_proto_failed:
1709 	unregister_pernet_device(&ip6gre_net_ops);
1710 	goto out;
1711 }
1712 
1713 static void __exit ip6gre_fini(void)
1714 {
1715 	rtnl_link_unregister(&ip6gre_tap_ops);
1716 	rtnl_link_unregister(&ip6gre_link_ops);
1717 	inet6_del_protocol(&ip6gre_protocol, IPPROTO_GRE);
1718 	unregister_pernet_device(&ip6gre_net_ops);
1719 }
1720 
1721 module_init(ip6gre_init);
1722 module_exit(ip6gre_fini);
1723 MODULE_LICENSE("GPL");
1724 MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
1725 MODULE_DESCRIPTION("GRE over IPv6 tunneling device");
1726 MODULE_ALIAS_RTNL_LINK("ip6gre");
1727 MODULE_ALIAS_RTNL_LINK("ip6gretap");
1728 MODULE_ALIAS_NETDEV("ip6gre0");
1729