xref: /openbmc/linux/net/ipv6/sit.c (revision a36954f5)
1 /*
2  *	IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
8  *
9  *	This program is free software; you can redistribute it and/or
10  *      modify it under the terms of the GNU General Public License
11  *      as published by the Free Software Foundation; either version
12  *      2 of the License, or (at your option) any later version.
13  *
14  *	Changes:
15  * Roger Venning <r.venning@telstra.com>:	6to4 support
16  * Nate Thompson <nate@thebog.net>:		6to4 support
17  * Fred Templin <fred.l.templin@boeing.com>:	isatap support
18  */
19 
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 
22 #include <linux/module.h>
23 #include <linux/capability.h>
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/in6.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_arp.h>
32 #include <linux/icmp.h>
33 #include <linux/slab.h>
34 #include <linux/uaccess.h>
35 #include <linux/init.h>
36 #include <linux/netfilter_ipv4.h>
37 #include <linux/if_ether.h>
38 
39 #include <net/sock.h>
40 #include <net/snmp.h>
41 
42 #include <net/ipv6.h>
43 #include <net/protocol.h>
44 #include <net/transp_v6.h>
45 #include <net/ip6_fib.h>
46 #include <net/ip6_route.h>
47 #include <net/ndisc.h>
48 #include <net/addrconf.h>
49 #include <net/ip.h>
50 #include <net/udp.h>
51 #include <net/icmp.h>
52 #include <net/ip_tunnels.h>
53 #include <net/inet_ecn.h>
54 #include <net/xfrm.h>
55 #include <net/dsfield.h>
56 #include <net/net_namespace.h>
57 #include <net/netns/generic.h>
58 
59 /*
60    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
61 
62    For comments look at net/ipv4/ip_gre.c --ANK
63  */
64 
65 #define IP6_SIT_HASH_SIZE  16
66 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
67 
68 static bool log_ecn_error = true;
69 module_param(log_ecn_error, bool, 0644);
70 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
71 
72 static int ipip6_tunnel_init(struct net_device *dev);
73 static void ipip6_tunnel_setup(struct net_device *dev);
74 static void ipip6_dev_free(struct net_device *dev);
75 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
76 		      __be32 *v4dst);
77 static struct rtnl_link_ops sit_link_ops __read_mostly;
78 
79 static unsigned int sit_net_id __read_mostly;
80 struct sit_net {
81 	struct ip_tunnel __rcu *tunnels_r_l[IP6_SIT_HASH_SIZE];
82 	struct ip_tunnel __rcu *tunnels_r[IP6_SIT_HASH_SIZE];
83 	struct ip_tunnel __rcu *tunnels_l[IP6_SIT_HASH_SIZE];
84 	struct ip_tunnel __rcu *tunnels_wc[1];
85 	struct ip_tunnel __rcu **tunnels[4];
86 
87 	struct net_device *fb_tunnel_dev;
88 };
89 
90 /*
91  * Must be invoked with rcu_read_lock
92  */
93 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
94 		struct net_device *dev, __be32 remote, __be32 local)
95 {
96 	unsigned int h0 = HASH(remote);
97 	unsigned int h1 = HASH(local);
98 	struct ip_tunnel *t;
99 	struct sit_net *sitn = net_generic(net, sit_net_id);
100 
101 	for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
102 		if (local == t->parms.iph.saddr &&
103 		    remote == t->parms.iph.daddr &&
104 		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
105 		    (t->dev->flags & IFF_UP))
106 			return t;
107 	}
108 	for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
109 		if (remote == t->parms.iph.daddr &&
110 		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
111 		    (t->dev->flags & IFF_UP))
112 			return t;
113 	}
114 	for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
115 		if (local == t->parms.iph.saddr &&
116 		    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
117 		    (t->dev->flags & IFF_UP))
118 			return t;
119 	}
120 	t = rcu_dereference(sitn->tunnels_wc[0]);
121 	if (t && (t->dev->flags & IFF_UP))
122 		return t;
123 	return NULL;
124 }
125 
126 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
127 		struct ip_tunnel_parm *parms)
128 {
129 	__be32 remote = parms->iph.daddr;
130 	__be32 local = parms->iph.saddr;
131 	unsigned int h = 0;
132 	int prio = 0;
133 
134 	if (remote) {
135 		prio |= 2;
136 		h ^= HASH(remote);
137 	}
138 	if (local) {
139 		prio |= 1;
140 		h ^= HASH(local);
141 	}
142 	return &sitn->tunnels[prio][h];
143 }
144 
145 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
146 		struct ip_tunnel *t)
147 {
148 	return __ipip6_bucket(sitn, &t->parms);
149 }
150 
151 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
152 {
153 	struct ip_tunnel __rcu **tp;
154 	struct ip_tunnel *iter;
155 
156 	for (tp = ipip6_bucket(sitn, t);
157 	     (iter = rtnl_dereference(*tp)) != NULL;
158 	     tp = &iter->next) {
159 		if (t == iter) {
160 			rcu_assign_pointer(*tp, t->next);
161 			break;
162 		}
163 	}
164 }
165 
166 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
167 {
168 	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
169 
170 	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
171 	rcu_assign_pointer(*tp, t);
172 }
173 
174 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
175 {
176 #ifdef CONFIG_IPV6_SIT_6RD
177 	struct ip_tunnel *t = netdev_priv(dev);
178 
179 	if (t->dev == sitn->fb_tunnel_dev) {
180 		ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
181 		t->ip6rd.relay_prefix = 0;
182 		t->ip6rd.prefixlen = 16;
183 		t->ip6rd.relay_prefixlen = 0;
184 	} else {
185 		struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
186 		memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
187 	}
188 #endif
189 }
190 
191 static int ipip6_tunnel_create(struct net_device *dev)
192 {
193 	struct ip_tunnel *t = netdev_priv(dev);
194 	struct net *net = dev_net(dev);
195 	struct sit_net *sitn = net_generic(net, sit_net_id);
196 	int err;
197 
198 	memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
199 	memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
200 
201 	if ((__force u16)t->parms.i_flags & SIT_ISATAP)
202 		dev->priv_flags |= IFF_ISATAP;
203 
204 	dev->rtnl_link_ops = &sit_link_ops;
205 
206 	err = register_netdevice(dev);
207 	if (err < 0)
208 		goto out;
209 
210 	ipip6_tunnel_clone_6rd(dev, sitn);
211 
212 	dev_hold(dev);
213 
214 	ipip6_tunnel_link(sitn, t);
215 	return 0;
216 
217 out:
218 	return err;
219 }
220 
221 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
222 		struct ip_tunnel_parm *parms, int create)
223 {
224 	__be32 remote = parms->iph.daddr;
225 	__be32 local = parms->iph.saddr;
226 	struct ip_tunnel *t, *nt;
227 	struct ip_tunnel __rcu **tp;
228 	struct net_device *dev;
229 	char name[IFNAMSIZ];
230 	struct sit_net *sitn = net_generic(net, sit_net_id);
231 
232 	for (tp = __ipip6_bucket(sitn, parms);
233 	    (t = rtnl_dereference(*tp)) != NULL;
234 	     tp = &t->next) {
235 		if (local == t->parms.iph.saddr &&
236 		    remote == t->parms.iph.daddr &&
237 		    parms->link == t->parms.link) {
238 			if (create)
239 				return NULL;
240 			else
241 				return t;
242 		}
243 	}
244 	if (!create)
245 		goto failed;
246 
247 	if (parms->name[0])
248 		strlcpy(name, parms->name, IFNAMSIZ);
249 	else
250 		strcpy(name, "sit%d");
251 
252 	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
253 			   ipip6_tunnel_setup);
254 	if (!dev)
255 		return NULL;
256 
257 	dev_net_set(dev, net);
258 
259 	nt = netdev_priv(dev);
260 
261 	nt->parms = *parms;
262 	if (ipip6_tunnel_create(dev) < 0)
263 		goto failed_free;
264 
265 	return nt;
266 
267 failed_free:
268 	ipip6_dev_free(dev);
269 failed:
270 	return NULL;
271 }
272 
273 #define for_each_prl_rcu(start)			\
274 	for (prl = rcu_dereference(start);	\
275 	     prl;				\
276 	     prl = rcu_dereference(prl->next))
277 
278 static struct ip_tunnel_prl_entry *
279 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
280 {
281 	struct ip_tunnel_prl_entry *prl;
282 
283 	for_each_prl_rcu(t->prl)
284 		if (prl->addr == addr)
285 			break;
286 	return prl;
287 
288 }
289 
290 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
291 				struct ip_tunnel_prl __user *a)
292 {
293 	struct ip_tunnel_prl kprl, *kp;
294 	struct ip_tunnel_prl_entry *prl;
295 	unsigned int cmax, c = 0, ca, len;
296 	int ret = 0;
297 
298 	if (copy_from_user(&kprl, a, sizeof(kprl)))
299 		return -EFAULT;
300 	cmax = kprl.datalen / sizeof(kprl);
301 	if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
302 		cmax = 1;
303 
304 	/* For simple GET or for root users,
305 	 * we try harder to allocate.
306 	 */
307 	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
308 		kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
309 		NULL;
310 
311 	rcu_read_lock();
312 
313 	ca = t->prl_count < cmax ? t->prl_count : cmax;
314 
315 	if (!kp) {
316 		/* We don't try hard to allocate much memory for
317 		 * non-root users.
318 		 * For root users, retry allocating enough memory for
319 		 * the answer.
320 		 */
321 		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
322 		if (!kp) {
323 			ret = -ENOMEM;
324 			goto out;
325 		}
326 	}
327 
328 	c = 0;
329 	for_each_prl_rcu(t->prl) {
330 		if (c >= cmax)
331 			break;
332 		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
333 			continue;
334 		kp[c].addr = prl->addr;
335 		kp[c].flags = prl->flags;
336 		c++;
337 		if (kprl.addr != htonl(INADDR_ANY))
338 			break;
339 	}
340 out:
341 	rcu_read_unlock();
342 
343 	len = sizeof(*kp) * c;
344 	ret = 0;
345 	if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
346 		ret = -EFAULT;
347 
348 	kfree(kp);
349 
350 	return ret;
351 }
352 
353 static int
354 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
355 {
356 	struct ip_tunnel_prl_entry *p;
357 	int err = 0;
358 
359 	if (a->addr == htonl(INADDR_ANY))
360 		return -EINVAL;
361 
362 	ASSERT_RTNL();
363 
364 	for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
365 		if (p->addr == a->addr) {
366 			if (chg) {
367 				p->flags = a->flags;
368 				goto out;
369 			}
370 			err = -EEXIST;
371 			goto out;
372 		}
373 	}
374 
375 	if (chg) {
376 		err = -ENXIO;
377 		goto out;
378 	}
379 
380 	p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
381 	if (!p) {
382 		err = -ENOBUFS;
383 		goto out;
384 	}
385 
386 	p->next = t->prl;
387 	p->addr = a->addr;
388 	p->flags = a->flags;
389 	t->prl_count++;
390 	rcu_assign_pointer(t->prl, p);
391 out:
392 	return err;
393 }
394 
395 static void prl_list_destroy_rcu(struct rcu_head *head)
396 {
397 	struct ip_tunnel_prl_entry *p, *n;
398 
399 	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
400 	do {
401 		n = rcu_dereference_protected(p->next, 1);
402 		kfree(p);
403 		p = n;
404 	} while (p);
405 }
406 
407 static int
408 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
409 {
410 	struct ip_tunnel_prl_entry *x;
411 	struct ip_tunnel_prl_entry __rcu **p;
412 	int err = 0;
413 
414 	ASSERT_RTNL();
415 
416 	if (a && a->addr != htonl(INADDR_ANY)) {
417 		for (p = &t->prl;
418 		     (x = rtnl_dereference(*p)) != NULL;
419 		     p = &x->next) {
420 			if (x->addr == a->addr) {
421 				*p = x->next;
422 				kfree_rcu(x, rcu_head);
423 				t->prl_count--;
424 				goto out;
425 			}
426 		}
427 		err = -ENXIO;
428 	} else {
429 		x = rtnl_dereference(t->prl);
430 		if (x) {
431 			t->prl_count = 0;
432 			call_rcu(&x->rcu_head, prl_list_destroy_rcu);
433 			t->prl = NULL;
434 		}
435 	}
436 out:
437 	return err;
438 }
439 
440 static int
441 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
442 {
443 	struct ip_tunnel_prl_entry *p;
444 	int ok = 1;
445 
446 	rcu_read_lock();
447 	p = __ipip6_tunnel_locate_prl(t, iph->saddr);
448 	if (p) {
449 		if (p->flags & PRL_DEFAULT)
450 			skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
451 		else
452 			skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
453 	} else {
454 		const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
455 
456 		if (ipv6_addr_is_isatap(addr6) &&
457 		    (addr6->s6_addr32[3] == iph->saddr) &&
458 		    ipv6_chk_prefix(addr6, t->dev))
459 			skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
460 		else
461 			ok = 0;
462 	}
463 	rcu_read_unlock();
464 	return ok;
465 }
466 
467 static void ipip6_tunnel_uninit(struct net_device *dev)
468 {
469 	struct ip_tunnel *tunnel = netdev_priv(dev);
470 	struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
471 
472 	if (dev == sitn->fb_tunnel_dev) {
473 		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
474 	} else {
475 		ipip6_tunnel_unlink(sitn, tunnel);
476 		ipip6_tunnel_del_prl(tunnel, NULL);
477 	}
478 	dst_cache_reset(&tunnel->dst_cache);
479 	dev_put(dev);
480 }
481 
482 static int ipip6_err(struct sk_buff *skb, u32 info)
483 {
484 	const struct iphdr *iph = (const struct iphdr *)skb->data;
485 	const int type = icmp_hdr(skb)->type;
486 	const int code = icmp_hdr(skb)->code;
487 	unsigned int data_len = 0;
488 	struct ip_tunnel *t;
489 	int err;
490 
491 	switch (type) {
492 	default:
493 	case ICMP_PARAMETERPROB:
494 		return 0;
495 
496 	case ICMP_DEST_UNREACH:
497 		switch (code) {
498 		case ICMP_SR_FAILED:
499 			/* Impossible event. */
500 			return 0;
501 		default:
502 			/* All others are translated to HOST_UNREACH.
503 			   rfc2003 contains "deep thoughts" about NET_UNREACH,
504 			   I believe they are just ether pollution. --ANK
505 			 */
506 			break;
507 		}
508 		break;
509 	case ICMP_TIME_EXCEEDED:
510 		if (code != ICMP_EXC_TTL)
511 			return 0;
512 		data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
513 		break;
514 	case ICMP_REDIRECT:
515 		break;
516 	}
517 
518 	err = -ENOENT;
519 
520 	t = ipip6_tunnel_lookup(dev_net(skb->dev),
521 				skb->dev,
522 				iph->daddr,
523 				iph->saddr);
524 	if (!t)
525 		goto out;
526 
527 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
528 		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
529 				 t->parms.link, 0, iph->protocol, 0);
530 		err = 0;
531 		goto out;
532 	}
533 	if (type == ICMP_REDIRECT) {
534 		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
535 			      iph->protocol, 0);
536 		err = 0;
537 		goto out;
538 	}
539 
540 	err = 0;
541 	if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
542 		goto out;
543 
544 	if (t->parms.iph.daddr == 0)
545 		goto out;
546 
547 	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
548 		goto out;
549 
550 	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
551 		t->err_count++;
552 	else
553 		t->err_count = 1;
554 	t->err_time = jiffies;
555 out:
556 	return err;
557 }
558 
559 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
560 				  const struct in6_addr *v6addr)
561 {
562 	__be32 v4embed = 0;
563 	if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
564 		return true;
565 	return false;
566 }
567 
568 /* Checks if an address matches an address on the tunnel interface.
569  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
570  * Long story:
571  * This function is called after we considered the packet as spoofed
572  * in is_spoofed_6rd.
573  * We may have a router that is doing NAT for proto 41 packets
574  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
575  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
576  * function will return true, dropping the packet.
577  * But, we can still check if is spoofed against the IP
578  * addresses associated with the interface.
579  */
580 static bool only_dnatted(const struct ip_tunnel *tunnel,
581 	const struct in6_addr *v6dst)
582 {
583 	int prefix_len;
584 
585 #ifdef CONFIG_IPV6_SIT_6RD
586 	prefix_len = tunnel->ip6rd.prefixlen + 32
587 		- tunnel->ip6rd.relay_prefixlen;
588 #else
589 	prefix_len = 48;
590 #endif
591 	return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
592 }
593 
594 /* Returns true if a packet is spoofed */
595 static bool packet_is_spoofed(struct sk_buff *skb,
596 			      const struct iphdr *iph,
597 			      struct ip_tunnel *tunnel)
598 {
599 	const struct ipv6hdr *ipv6h;
600 
601 	if (tunnel->dev->priv_flags & IFF_ISATAP) {
602 		if (!isatap_chksrc(skb, iph, tunnel))
603 			return true;
604 
605 		return false;
606 	}
607 
608 	if (tunnel->dev->flags & IFF_POINTOPOINT)
609 		return false;
610 
611 	ipv6h = ipv6_hdr(skb);
612 
613 	if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
614 		net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
615 				     &iph->saddr, &ipv6h->saddr,
616 				     &iph->daddr, &ipv6h->daddr);
617 		return true;
618 	}
619 
620 	if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
621 		return false;
622 
623 	if (only_dnatted(tunnel, &ipv6h->daddr))
624 		return false;
625 
626 	net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
627 			     &iph->saddr, &ipv6h->saddr,
628 			     &iph->daddr, &ipv6h->daddr);
629 	return true;
630 }
631 
632 static int ipip6_rcv(struct sk_buff *skb)
633 {
634 	const struct iphdr *iph = ip_hdr(skb);
635 	struct ip_tunnel *tunnel;
636 	int err;
637 
638 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
639 				     iph->saddr, iph->daddr);
640 	if (tunnel) {
641 		struct pcpu_sw_netstats *tstats;
642 
643 		if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
644 		    tunnel->parms.iph.protocol != 0)
645 			goto out;
646 
647 		skb->mac_header = skb->network_header;
648 		skb_reset_network_header(skb);
649 		IPCB(skb)->flags = 0;
650 		skb->dev = tunnel->dev;
651 
652 		if (packet_is_spoofed(skb, iph, tunnel)) {
653 			tunnel->dev->stats.rx_errors++;
654 			goto out;
655 		}
656 
657 		if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
658 		    !net_eq(tunnel->net, dev_net(tunnel->dev))))
659 			goto out;
660 
661 		err = IP_ECN_decapsulate(iph, skb);
662 		if (unlikely(err)) {
663 			if (log_ecn_error)
664 				net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
665 						     &iph->saddr, iph->tos);
666 			if (err > 1) {
667 				++tunnel->dev->stats.rx_frame_errors;
668 				++tunnel->dev->stats.rx_errors;
669 				goto out;
670 			}
671 		}
672 
673 		tstats = this_cpu_ptr(tunnel->dev->tstats);
674 		u64_stats_update_begin(&tstats->syncp);
675 		tstats->rx_packets++;
676 		tstats->rx_bytes += skb->len;
677 		u64_stats_update_end(&tstats->syncp);
678 
679 		netif_rx(skb);
680 
681 		return 0;
682 	}
683 
684 	/* no tunnel matched,  let upstream know, ipsec may handle it */
685 	return 1;
686 out:
687 	kfree_skb(skb);
688 	return 0;
689 }
690 
691 static const struct tnl_ptk_info ipip_tpi = {
692 	/* no tunnel info required for ipip. */
693 	.proto = htons(ETH_P_IP),
694 };
695 
696 #if IS_ENABLED(CONFIG_MPLS)
697 static const struct tnl_ptk_info mplsip_tpi = {
698 	/* no tunnel info required for mplsip. */
699 	.proto = htons(ETH_P_MPLS_UC),
700 };
701 #endif
702 
703 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
704 {
705 	const struct iphdr *iph;
706 	struct ip_tunnel *tunnel;
707 
708 	iph = ip_hdr(skb);
709 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
710 				     iph->saddr, iph->daddr);
711 	if (tunnel) {
712 		const struct tnl_ptk_info *tpi;
713 
714 		if (tunnel->parms.iph.protocol != ipproto &&
715 		    tunnel->parms.iph.protocol != 0)
716 			goto drop;
717 
718 		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
719 			goto drop;
720 #if IS_ENABLED(CONFIG_MPLS)
721 		if (ipproto == IPPROTO_MPLS)
722 			tpi = &mplsip_tpi;
723 		else
724 #endif
725 			tpi = &ipip_tpi;
726 		if (iptunnel_pull_header(skb, 0, tpi->proto, false))
727 			goto drop;
728 		return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
729 	}
730 
731 	return 1;
732 
733 drop:
734 	kfree_skb(skb);
735 	return 0;
736 }
737 
738 static int ipip_rcv(struct sk_buff *skb)
739 {
740 	return sit_tunnel_rcv(skb, IPPROTO_IPIP);
741 }
742 
743 #if IS_ENABLED(CONFIG_MPLS)
744 static int mplsip_rcv(struct sk_buff *skb)
745 {
746 	return sit_tunnel_rcv(skb, IPPROTO_MPLS);
747 }
748 #endif
749 
750 /*
751  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
752  * stores the embedded IPv4 address in v4dst and returns true.
753  */
754 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
755 		      __be32 *v4dst)
756 {
757 #ifdef CONFIG_IPV6_SIT_6RD
758 	if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
759 			      tunnel->ip6rd.prefixlen)) {
760 		unsigned int pbw0, pbi0;
761 		int pbi1;
762 		u32 d;
763 
764 		pbw0 = tunnel->ip6rd.prefixlen >> 5;
765 		pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
766 
767 		d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
768 		    tunnel->ip6rd.relay_prefixlen;
769 
770 		pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
771 		if (pbi1 > 0)
772 			d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
773 			     (32 - pbi1);
774 
775 		*v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
776 		return true;
777 	}
778 #else
779 	if (v6dst->s6_addr16[0] == htons(0x2002)) {
780 		/* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
781 		memcpy(v4dst, &v6dst->s6_addr16[1], 4);
782 		return true;
783 	}
784 #endif
785 	return false;
786 }
787 
788 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
789 			     const struct in6_addr *v6dst)
790 {
791 	__be32 dst = 0;
792 	check_6rd(tunnel, v6dst, &dst);
793 	return dst;
794 }
795 
796 /*
797  *	This function assumes it is being called from dev_queue_xmit()
798  *	and that skb is filled properly by that function.
799  */
800 
801 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
802 				     struct net_device *dev)
803 {
804 	struct ip_tunnel *tunnel = netdev_priv(dev);
805 	const struct iphdr  *tiph = &tunnel->parms.iph;
806 	const struct ipv6hdr *iph6 = ipv6_hdr(skb);
807 	u8     tos = tunnel->parms.iph.tos;
808 	__be16 df = tiph->frag_off;
809 	struct rtable *rt;		/* Route to the other host */
810 	struct net_device *tdev;	/* Device to other host */
811 	unsigned int max_headroom;	/* The extra header space needed */
812 	__be32 dst = tiph->daddr;
813 	struct flowi4 fl4;
814 	int    mtu;
815 	const struct in6_addr *addr6;
816 	int addr_type;
817 	u8 ttl;
818 	u8 protocol = IPPROTO_IPV6;
819 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
820 
821 	if (tos == 1)
822 		tos = ipv6_get_dsfield(iph6);
823 
824 	/* ISATAP (RFC4214) - must come before 6to4 */
825 	if (dev->priv_flags & IFF_ISATAP) {
826 		struct neighbour *neigh = NULL;
827 		bool do_tx_error = false;
828 
829 		if (skb_dst(skb))
830 			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
831 
832 		if (!neigh) {
833 			net_dbg_ratelimited("nexthop == NULL\n");
834 			goto tx_error;
835 		}
836 
837 		addr6 = (const struct in6_addr *)&neigh->primary_key;
838 		addr_type = ipv6_addr_type(addr6);
839 
840 		if ((addr_type & IPV6_ADDR_UNICAST) &&
841 		     ipv6_addr_is_isatap(addr6))
842 			dst = addr6->s6_addr32[3];
843 		else
844 			do_tx_error = true;
845 
846 		neigh_release(neigh);
847 		if (do_tx_error)
848 			goto tx_error;
849 	}
850 
851 	if (!dst)
852 		dst = try_6rd(tunnel, &iph6->daddr);
853 
854 	if (!dst) {
855 		struct neighbour *neigh = NULL;
856 		bool do_tx_error = false;
857 
858 		if (skb_dst(skb))
859 			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
860 
861 		if (!neigh) {
862 			net_dbg_ratelimited("nexthop == NULL\n");
863 			goto tx_error;
864 		}
865 
866 		addr6 = (const struct in6_addr *)&neigh->primary_key;
867 		addr_type = ipv6_addr_type(addr6);
868 
869 		if (addr_type == IPV6_ADDR_ANY) {
870 			addr6 = &ipv6_hdr(skb)->daddr;
871 			addr_type = ipv6_addr_type(addr6);
872 		}
873 
874 		if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
875 			dst = addr6->s6_addr32[3];
876 		else
877 			do_tx_error = true;
878 
879 		neigh_release(neigh);
880 		if (do_tx_error)
881 			goto tx_error;
882 	}
883 
884 	flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
885 			   RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
886 			   0, dst, tiph->saddr, 0, 0,
887 			   sock_net_uid(tunnel->net, NULL));
888 	rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
889 
890 	if (IS_ERR(rt)) {
891 		dev->stats.tx_carrier_errors++;
892 		goto tx_error_icmp;
893 	}
894 	if (rt->rt_type != RTN_UNICAST) {
895 		ip_rt_put(rt);
896 		dev->stats.tx_carrier_errors++;
897 		goto tx_error_icmp;
898 	}
899 	tdev = rt->dst.dev;
900 
901 	if (tdev == dev) {
902 		ip_rt_put(rt);
903 		dev->stats.collisions++;
904 		goto tx_error;
905 	}
906 
907 	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
908 		ip_rt_put(rt);
909 		goto tx_error;
910 	}
911 
912 	if (df) {
913 		mtu = dst_mtu(&rt->dst) - t_hlen;
914 
915 		if (mtu < 68) {
916 			dev->stats.collisions++;
917 			ip_rt_put(rt);
918 			goto tx_error;
919 		}
920 
921 		if (mtu < IPV6_MIN_MTU) {
922 			mtu = IPV6_MIN_MTU;
923 			df = 0;
924 		}
925 
926 		if (tunnel->parms.iph.daddr && skb_dst(skb))
927 			skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
928 
929 		if (skb->len > mtu && !skb_is_gso(skb)) {
930 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
931 			ip_rt_put(rt);
932 			goto tx_error;
933 		}
934 	}
935 
936 	if (tunnel->err_count > 0) {
937 		if (time_before(jiffies,
938 				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
939 			tunnel->err_count--;
940 			dst_link_failure(skb);
941 		} else
942 			tunnel->err_count = 0;
943 	}
944 
945 	/*
946 	 * Okay, now see if we can stuff it in the buffer as-is.
947 	 */
948 	max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
949 
950 	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
951 	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
952 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
953 		if (!new_skb) {
954 			ip_rt_put(rt);
955 			dev->stats.tx_dropped++;
956 			kfree_skb(skb);
957 			return NETDEV_TX_OK;
958 		}
959 		if (skb->sk)
960 			skb_set_owner_w(new_skb, skb->sk);
961 		dev_kfree_skb(skb);
962 		skb = new_skb;
963 		iph6 = ipv6_hdr(skb);
964 	}
965 	ttl = tiph->ttl;
966 	if (ttl == 0)
967 		ttl = iph6->hop_limit;
968 	tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
969 
970 	if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
971 		ip_rt_put(rt);
972 		goto tx_error;
973 	}
974 
975 	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
976 
977 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
978 		      df, !net_eq(tunnel->net, dev_net(dev)));
979 	return NETDEV_TX_OK;
980 
981 tx_error_icmp:
982 	dst_link_failure(skb);
983 tx_error:
984 	kfree_skb(skb);
985 	dev->stats.tx_errors++;
986 	return NETDEV_TX_OK;
987 }
988 
989 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
990 				     struct net_device *dev, u8 ipproto)
991 {
992 	struct ip_tunnel *tunnel = netdev_priv(dev);
993 	const struct iphdr  *tiph = &tunnel->parms.iph;
994 
995 	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
996 		goto tx_error;
997 
998 	skb_set_inner_ipproto(skb, ipproto);
999 
1000 	ip_tunnel_xmit(skb, dev, tiph, ipproto);
1001 	return NETDEV_TX_OK;
1002 tx_error:
1003 	kfree_skb(skb);
1004 	dev->stats.tx_errors++;
1005 	return NETDEV_TX_OK;
1006 }
1007 
1008 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1009 				   struct net_device *dev)
1010 {
1011 	switch (skb->protocol) {
1012 	case htons(ETH_P_IP):
1013 		sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1014 		break;
1015 	case htons(ETH_P_IPV6):
1016 		ipip6_tunnel_xmit(skb, dev);
1017 		break;
1018 #if IS_ENABLED(CONFIG_MPLS)
1019 	case htons(ETH_P_MPLS_UC):
1020 		sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1021 		break;
1022 #endif
1023 	default:
1024 		goto tx_err;
1025 	}
1026 
1027 	return NETDEV_TX_OK;
1028 
1029 tx_err:
1030 	dev->stats.tx_errors++;
1031 	kfree_skb(skb);
1032 	return NETDEV_TX_OK;
1033 
1034 }
1035 
1036 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1037 {
1038 	struct net_device *tdev = NULL;
1039 	struct ip_tunnel *tunnel;
1040 	const struct iphdr *iph;
1041 	struct flowi4 fl4;
1042 
1043 	tunnel = netdev_priv(dev);
1044 	iph = &tunnel->parms.iph;
1045 
1046 	if (iph->daddr) {
1047 		struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1048 							  NULL,
1049 							  iph->daddr, iph->saddr,
1050 							  0, 0,
1051 							  IPPROTO_IPV6,
1052 							  RT_TOS(iph->tos),
1053 							  tunnel->parms.link);
1054 
1055 		if (!IS_ERR(rt)) {
1056 			tdev = rt->dst.dev;
1057 			ip_rt_put(rt);
1058 		}
1059 		dev->flags |= IFF_POINTOPOINT;
1060 	}
1061 
1062 	if (!tdev && tunnel->parms.link)
1063 		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1064 
1065 	if (tdev) {
1066 		int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1067 
1068 		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1069 		dev->mtu = tdev->mtu - t_hlen;
1070 		if (dev->mtu < IPV6_MIN_MTU)
1071 			dev->mtu = IPV6_MIN_MTU;
1072 	}
1073 }
1074 
1075 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
1076 				__u32 fwmark)
1077 {
1078 	struct net *net = t->net;
1079 	struct sit_net *sitn = net_generic(net, sit_net_id);
1080 
1081 	ipip6_tunnel_unlink(sitn, t);
1082 	synchronize_net();
1083 	t->parms.iph.saddr = p->iph.saddr;
1084 	t->parms.iph.daddr = p->iph.daddr;
1085 	memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1086 	memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1087 	ipip6_tunnel_link(sitn, t);
1088 	t->parms.iph.ttl = p->iph.ttl;
1089 	t->parms.iph.tos = p->iph.tos;
1090 	if (t->parms.link != p->link || t->fwmark != fwmark) {
1091 		t->parms.link = p->link;
1092 		t->fwmark = fwmark;
1093 		ipip6_tunnel_bind_dev(t->dev);
1094 	}
1095 	dst_cache_reset(&t->dst_cache);
1096 	netdev_state_change(t->dev);
1097 }
1098 
1099 #ifdef CONFIG_IPV6_SIT_6RD
1100 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1101 				   struct ip_tunnel_6rd *ip6rd)
1102 {
1103 	struct in6_addr prefix;
1104 	__be32 relay_prefix;
1105 
1106 	if (ip6rd->relay_prefixlen > 32 ||
1107 	    ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1108 		return -EINVAL;
1109 
1110 	ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1111 	if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1112 		return -EINVAL;
1113 	if (ip6rd->relay_prefixlen)
1114 		relay_prefix = ip6rd->relay_prefix &
1115 			       htonl(0xffffffffUL <<
1116 				     (32 - ip6rd->relay_prefixlen));
1117 	else
1118 		relay_prefix = 0;
1119 	if (relay_prefix != ip6rd->relay_prefix)
1120 		return -EINVAL;
1121 
1122 	t->ip6rd.prefix = prefix;
1123 	t->ip6rd.relay_prefix = relay_prefix;
1124 	t->ip6rd.prefixlen = ip6rd->prefixlen;
1125 	t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1126 	dst_cache_reset(&t->dst_cache);
1127 	netdev_state_change(t->dev);
1128 	return 0;
1129 }
1130 #endif
1131 
1132 static bool ipip6_valid_ip_proto(u8 ipproto)
1133 {
1134 	return ipproto == IPPROTO_IPV6 ||
1135 		ipproto == IPPROTO_IPIP ||
1136 #if IS_ENABLED(CONFIG_MPLS)
1137 		ipproto == IPPROTO_MPLS ||
1138 #endif
1139 		ipproto == 0;
1140 }
1141 
1142 static int
1143 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1144 {
1145 	int err = 0;
1146 	struct ip_tunnel_parm p;
1147 	struct ip_tunnel_prl prl;
1148 	struct ip_tunnel *t = netdev_priv(dev);
1149 	struct net *net = t->net;
1150 	struct sit_net *sitn = net_generic(net, sit_net_id);
1151 #ifdef CONFIG_IPV6_SIT_6RD
1152 	struct ip_tunnel_6rd ip6rd;
1153 #endif
1154 
1155 	switch (cmd) {
1156 	case SIOCGETTUNNEL:
1157 #ifdef CONFIG_IPV6_SIT_6RD
1158 	case SIOCGET6RD:
1159 #endif
1160 		if (dev == sitn->fb_tunnel_dev) {
1161 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1162 				err = -EFAULT;
1163 				break;
1164 			}
1165 			t = ipip6_tunnel_locate(net, &p, 0);
1166 			if (!t)
1167 				t = netdev_priv(dev);
1168 		}
1169 
1170 		err = -EFAULT;
1171 		if (cmd == SIOCGETTUNNEL) {
1172 			memcpy(&p, &t->parms, sizeof(p));
1173 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1174 					 sizeof(p)))
1175 				goto done;
1176 #ifdef CONFIG_IPV6_SIT_6RD
1177 		} else {
1178 			ip6rd.prefix = t->ip6rd.prefix;
1179 			ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1180 			ip6rd.prefixlen = t->ip6rd.prefixlen;
1181 			ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1182 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1183 					 sizeof(ip6rd)))
1184 				goto done;
1185 #endif
1186 		}
1187 		err = 0;
1188 		break;
1189 
1190 	case SIOCADDTUNNEL:
1191 	case SIOCCHGTUNNEL:
1192 		err = -EPERM;
1193 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1194 			goto done;
1195 
1196 		err = -EFAULT;
1197 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1198 			goto done;
1199 
1200 		err = -EINVAL;
1201 		if (!ipip6_valid_ip_proto(p.iph.protocol))
1202 			goto done;
1203 		if (p.iph.version != 4 ||
1204 		    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1205 			goto done;
1206 		if (p.iph.ttl)
1207 			p.iph.frag_off |= htons(IP_DF);
1208 
1209 		t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1210 
1211 		if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1212 			if (t) {
1213 				if (t->dev != dev) {
1214 					err = -EEXIST;
1215 					break;
1216 				}
1217 			} else {
1218 				if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1219 				    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1220 					err = -EINVAL;
1221 					break;
1222 				}
1223 				t = netdev_priv(dev);
1224 			}
1225 
1226 			ipip6_tunnel_update(t, &p, t->fwmark);
1227 		}
1228 
1229 		if (t) {
1230 			err = 0;
1231 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1232 				err = -EFAULT;
1233 		} else
1234 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1235 		break;
1236 
1237 	case SIOCDELTUNNEL:
1238 		err = -EPERM;
1239 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1240 			goto done;
1241 
1242 		if (dev == sitn->fb_tunnel_dev) {
1243 			err = -EFAULT;
1244 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1245 				goto done;
1246 			err = -ENOENT;
1247 			t = ipip6_tunnel_locate(net, &p, 0);
1248 			if (!t)
1249 				goto done;
1250 			err = -EPERM;
1251 			if (t == netdev_priv(sitn->fb_tunnel_dev))
1252 				goto done;
1253 			dev = t->dev;
1254 		}
1255 		unregister_netdevice(dev);
1256 		err = 0;
1257 		break;
1258 
1259 	case SIOCGETPRL:
1260 		err = -EINVAL;
1261 		if (dev == sitn->fb_tunnel_dev)
1262 			goto done;
1263 		err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1264 		break;
1265 
1266 	case SIOCADDPRL:
1267 	case SIOCDELPRL:
1268 	case SIOCCHGPRL:
1269 		err = -EPERM;
1270 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1271 			goto done;
1272 		err = -EINVAL;
1273 		if (dev == sitn->fb_tunnel_dev)
1274 			goto done;
1275 		err = -EFAULT;
1276 		if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1277 			goto done;
1278 
1279 		switch (cmd) {
1280 		case SIOCDELPRL:
1281 			err = ipip6_tunnel_del_prl(t, &prl);
1282 			break;
1283 		case SIOCADDPRL:
1284 		case SIOCCHGPRL:
1285 			err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1286 			break;
1287 		}
1288 		dst_cache_reset(&t->dst_cache);
1289 		netdev_state_change(dev);
1290 		break;
1291 
1292 #ifdef CONFIG_IPV6_SIT_6RD
1293 	case SIOCADD6RD:
1294 	case SIOCCHG6RD:
1295 	case SIOCDEL6RD:
1296 		err = -EPERM;
1297 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1298 			goto done;
1299 
1300 		err = -EFAULT;
1301 		if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1302 				   sizeof(ip6rd)))
1303 			goto done;
1304 
1305 		if (cmd != SIOCDEL6RD) {
1306 			err = ipip6_tunnel_update_6rd(t, &ip6rd);
1307 			if (err < 0)
1308 				goto done;
1309 		} else
1310 			ipip6_tunnel_clone_6rd(dev, sitn);
1311 
1312 		err = 0;
1313 		break;
1314 #endif
1315 
1316 	default:
1317 		err = -EINVAL;
1318 	}
1319 
1320 done:
1321 	return err;
1322 }
1323 
1324 static const struct net_device_ops ipip6_netdev_ops = {
1325 	.ndo_init	= ipip6_tunnel_init,
1326 	.ndo_uninit	= ipip6_tunnel_uninit,
1327 	.ndo_start_xmit	= sit_tunnel_xmit,
1328 	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
1329 	.ndo_get_stats64 = ip_tunnel_get_stats64,
1330 	.ndo_get_iflink = ip_tunnel_get_iflink,
1331 };
1332 
1333 static void ipip6_dev_free(struct net_device *dev)
1334 {
1335 	struct ip_tunnel *tunnel = netdev_priv(dev);
1336 
1337 	dst_cache_destroy(&tunnel->dst_cache);
1338 	free_percpu(dev->tstats);
1339 	free_netdev(dev);
1340 }
1341 
1342 #define SIT_FEATURES (NETIF_F_SG	   | \
1343 		      NETIF_F_FRAGLIST	   | \
1344 		      NETIF_F_HIGHDMA	   | \
1345 		      NETIF_F_GSO_SOFTWARE | \
1346 		      NETIF_F_HW_CSUM)
1347 
1348 static void ipip6_tunnel_setup(struct net_device *dev)
1349 {
1350 	struct ip_tunnel *tunnel = netdev_priv(dev);
1351 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1352 
1353 	dev->netdev_ops		= &ipip6_netdev_ops;
1354 	dev->destructor		= ipip6_dev_free;
1355 
1356 	dev->type		= ARPHRD_SIT;
1357 	dev->hard_header_len	= LL_MAX_HEADER + t_hlen;
1358 	dev->mtu		= ETH_DATA_LEN - t_hlen;
1359 	dev->min_mtu		= IPV6_MIN_MTU;
1360 	dev->max_mtu		= 0xFFF8 - t_hlen;
1361 	dev->flags		= IFF_NOARP;
1362 	netif_keep_dst(dev);
1363 	dev->addr_len		= 4;
1364 	dev->features		|= NETIF_F_LLTX;
1365 	dev->features		|= SIT_FEATURES;
1366 	dev->hw_features	|= SIT_FEATURES;
1367 }
1368 
1369 static int ipip6_tunnel_init(struct net_device *dev)
1370 {
1371 	struct ip_tunnel *tunnel = netdev_priv(dev);
1372 	int err;
1373 
1374 	tunnel->dev = dev;
1375 	tunnel->net = dev_net(dev);
1376 	strcpy(tunnel->parms.name, dev->name);
1377 
1378 	ipip6_tunnel_bind_dev(dev);
1379 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1380 	if (!dev->tstats)
1381 		return -ENOMEM;
1382 
1383 	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1384 	if (err) {
1385 		free_percpu(dev->tstats);
1386 		dev->tstats = NULL;
1387 		return err;
1388 	}
1389 
1390 	return 0;
1391 }
1392 
1393 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1394 {
1395 	struct ip_tunnel *tunnel = netdev_priv(dev);
1396 	struct iphdr *iph = &tunnel->parms.iph;
1397 	struct net *net = dev_net(dev);
1398 	struct sit_net *sitn = net_generic(net, sit_net_id);
1399 
1400 	iph->version		= 4;
1401 	iph->protocol		= IPPROTO_IPV6;
1402 	iph->ihl		= 5;
1403 	iph->ttl		= 64;
1404 
1405 	dev_hold(dev);
1406 	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1407 }
1408 
1409 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1410 {
1411 	u8 proto;
1412 
1413 	if (!data || !data[IFLA_IPTUN_PROTO])
1414 		return 0;
1415 
1416 	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1417 	if (!ipip6_valid_ip_proto(proto))
1418 		return -EINVAL;
1419 
1420 	return 0;
1421 }
1422 
1423 static void ipip6_netlink_parms(struct nlattr *data[],
1424 				struct ip_tunnel_parm *parms,
1425 				__u32 *fwmark)
1426 {
1427 	memset(parms, 0, sizeof(*parms));
1428 
1429 	parms->iph.version = 4;
1430 	parms->iph.protocol = IPPROTO_IPV6;
1431 	parms->iph.ihl = 5;
1432 	parms->iph.ttl = 64;
1433 
1434 	if (!data)
1435 		return;
1436 
1437 	if (data[IFLA_IPTUN_LINK])
1438 		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1439 
1440 	if (data[IFLA_IPTUN_LOCAL])
1441 		parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1442 
1443 	if (data[IFLA_IPTUN_REMOTE])
1444 		parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1445 
1446 	if (data[IFLA_IPTUN_TTL]) {
1447 		parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1448 		if (parms->iph.ttl)
1449 			parms->iph.frag_off = htons(IP_DF);
1450 	}
1451 
1452 	if (data[IFLA_IPTUN_TOS])
1453 		parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1454 
1455 	if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1456 		parms->iph.frag_off = htons(IP_DF);
1457 
1458 	if (data[IFLA_IPTUN_FLAGS])
1459 		parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1460 
1461 	if (data[IFLA_IPTUN_PROTO])
1462 		parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1463 
1464 	if (data[IFLA_IPTUN_FWMARK])
1465 		*fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1466 }
1467 
1468 /* This function returns true when ENCAP attributes are present in the nl msg */
1469 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1470 				      struct ip_tunnel_encap *ipencap)
1471 {
1472 	bool ret = false;
1473 
1474 	memset(ipencap, 0, sizeof(*ipencap));
1475 
1476 	if (!data)
1477 		return ret;
1478 
1479 	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1480 		ret = true;
1481 		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1482 	}
1483 
1484 	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1485 		ret = true;
1486 		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1487 	}
1488 
1489 	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1490 		ret = true;
1491 		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1492 	}
1493 
1494 	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1495 		ret = true;
1496 		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1497 	}
1498 
1499 	return ret;
1500 }
1501 
1502 #ifdef CONFIG_IPV6_SIT_6RD
1503 /* This function returns true when 6RD attributes are present in the nl msg */
1504 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1505 				    struct ip_tunnel_6rd *ip6rd)
1506 {
1507 	bool ret = false;
1508 	memset(ip6rd, 0, sizeof(*ip6rd));
1509 
1510 	if (!data)
1511 		return ret;
1512 
1513 	if (data[IFLA_IPTUN_6RD_PREFIX]) {
1514 		ret = true;
1515 		ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1516 	}
1517 
1518 	if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1519 		ret = true;
1520 		ip6rd->relay_prefix =
1521 			nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1522 	}
1523 
1524 	if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1525 		ret = true;
1526 		ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1527 	}
1528 
1529 	if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1530 		ret = true;
1531 		ip6rd->relay_prefixlen =
1532 			nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1533 	}
1534 
1535 	return ret;
1536 }
1537 #endif
1538 
1539 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1540 			 struct nlattr *tb[], struct nlattr *data[])
1541 {
1542 	struct net *net = dev_net(dev);
1543 	struct ip_tunnel *nt;
1544 	struct ip_tunnel_encap ipencap;
1545 #ifdef CONFIG_IPV6_SIT_6RD
1546 	struct ip_tunnel_6rd ip6rd;
1547 #endif
1548 	int err;
1549 
1550 	nt = netdev_priv(dev);
1551 
1552 	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1553 		err = ip_tunnel_encap_setup(nt, &ipencap);
1554 		if (err < 0)
1555 			return err;
1556 	}
1557 
1558 	ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1559 
1560 	if (ipip6_tunnel_locate(net, &nt->parms, 0))
1561 		return -EEXIST;
1562 
1563 	err = ipip6_tunnel_create(dev);
1564 	if (err < 0)
1565 		return err;
1566 
1567 #ifdef CONFIG_IPV6_SIT_6RD
1568 	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1569 		err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1570 #endif
1571 
1572 	return err;
1573 }
1574 
1575 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1576 			  struct nlattr *data[])
1577 {
1578 	struct ip_tunnel *t = netdev_priv(dev);
1579 	struct ip_tunnel_parm p;
1580 	struct ip_tunnel_encap ipencap;
1581 	struct net *net = t->net;
1582 	struct sit_net *sitn = net_generic(net, sit_net_id);
1583 #ifdef CONFIG_IPV6_SIT_6RD
1584 	struct ip_tunnel_6rd ip6rd;
1585 #endif
1586 	__u32 fwmark = t->fwmark;
1587 	int err;
1588 
1589 	if (dev == sitn->fb_tunnel_dev)
1590 		return -EINVAL;
1591 
1592 	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1593 		err = ip_tunnel_encap_setup(t, &ipencap);
1594 		if (err < 0)
1595 			return err;
1596 	}
1597 
1598 	ipip6_netlink_parms(data, &p, &fwmark);
1599 
1600 	if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1601 	    (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1602 		return -EINVAL;
1603 
1604 	t = ipip6_tunnel_locate(net, &p, 0);
1605 
1606 	if (t) {
1607 		if (t->dev != dev)
1608 			return -EEXIST;
1609 	} else
1610 		t = netdev_priv(dev);
1611 
1612 	ipip6_tunnel_update(t, &p, fwmark);
1613 
1614 #ifdef CONFIG_IPV6_SIT_6RD
1615 	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1616 		return ipip6_tunnel_update_6rd(t, &ip6rd);
1617 #endif
1618 
1619 	return 0;
1620 }
1621 
1622 static size_t ipip6_get_size(const struct net_device *dev)
1623 {
1624 	return
1625 		/* IFLA_IPTUN_LINK */
1626 		nla_total_size(4) +
1627 		/* IFLA_IPTUN_LOCAL */
1628 		nla_total_size(4) +
1629 		/* IFLA_IPTUN_REMOTE */
1630 		nla_total_size(4) +
1631 		/* IFLA_IPTUN_TTL */
1632 		nla_total_size(1) +
1633 		/* IFLA_IPTUN_TOS */
1634 		nla_total_size(1) +
1635 		/* IFLA_IPTUN_PMTUDISC */
1636 		nla_total_size(1) +
1637 		/* IFLA_IPTUN_FLAGS */
1638 		nla_total_size(2) +
1639 		/* IFLA_IPTUN_PROTO */
1640 		nla_total_size(1) +
1641 #ifdef CONFIG_IPV6_SIT_6RD
1642 		/* IFLA_IPTUN_6RD_PREFIX */
1643 		nla_total_size(sizeof(struct in6_addr)) +
1644 		/* IFLA_IPTUN_6RD_RELAY_PREFIX */
1645 		nla_total_size(4) +
1646 		/* IFLA_IPTUN_6RD_PREFIXLEN */
1647 		nla_total_size(2) +
1648 		/* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1649 		nla_total_size(2) +
1650 #endif
1651 		/* IFLA_IPTUN_ENCAP_TYPE */
1652 		nla_total_size(2) +
1653 		/* IFLA_IPTUN_ENCAP_FLAGS */
1654 		nla_total_size(2) +
1655 		/* IFLA_IPTUN_ENCAP_SPORT */
1656 		nla_total_size(2) +
1657 		/* IFLA_IPTUN_ENCAP_DPORT */
1658 		nla_total_size(2) +
1659 		/* IFLA_IPTUN_FWMARK */
1660 		nla_total_size(4) +
1661 		0;
1662 }
1663 
1664 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1665 {
1666 	struct ip_tunnel *tunnel = netdev_priv(dev);
1667 	struct ip_tunnel_parm *parm = &tunnel->parms;
1668 
1669 	if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1670 	    nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1671 	    nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1672 	    nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1673 	    nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1674 	    nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1675 		       !!(parm->iph.frag_off & htons(IP_DF))) ||
1676 	    nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1677 	    nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags) ||
1678 	    nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1679 		goto nla_put_failure;
1680 
1681 #ifdef CONFIG_IPV6_SIT_6RD
1682 	if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1683 			     &tunnel->ip6rd.prefix) ||
1684 	    nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1685 			    tunnel->ip6rd.relay_prefix) ||
1686 	    nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1687 			tunnel->ip6rd.prefixlen) ||
1688 	    nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1689 			tunnel->ip6rd.relay_prefixlen))
1690 		goto nla_put_failure;
1691 #endif
1692 
1693 	if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1694 			tunnel->encap.type) ||
1695 	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1696 			tunnel->encap.sport) ||
1697 	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1698 			tunnel->encap.dport) ||
1699 	    nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1700 			tunnel->encap.flags))
1701 		goto nla_put_failure;
1702 
1703 	return 0;
1704 
1705 nla_put_failure:
1706 	return -EMSGSIZE;
1707 }
1708 
1709 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1710 	[IFLA_IPTUN_LINK]		= { .type = NLA_U32 },
1711 	[IFLA_IPTUN_LOCAL]		= { .type = NLA_U32 },
1712 	[IFLA_IPTUN_REMOTE]		= { .type = NLA_U32 },
1713 	[IFLA_IPTUN_TTL]		= { .type = NLA_U8 },
1714 	[IFLA_IPTUN_TOS]		= { .type = NLA_U8 },
1715 	[IFLA_IPTUN_PMTUDISC]		= { .type = NLA_U8 },
1716 	[IFLA_IPTUN_FLAGS]		= { .type = NLA_U16 },
1717 	[IFLA_IPTUN_PROTO]		= { .type = NLA_U8 },
1718 #ifdef CONFIG_IPV6_SIT_6RD
1719 	[IFLA_IPTUN_6RD_PREFIX]		= { .len = sizeof(struct in6_addr) },
1720 	[IFLA_IPTUN_6RD_RELAY_PREFIX]	= { .type = NLA_U32 },
1721 	[IFLA_IPTUN_6RD_PREFIXLEN]	= { .type = NLA_U16 },
1722 	[IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1723 #endif
1724 	[IFLA_IPTUN_ENCAP_TYPE]		= { .type = NLA_U16 },
1725 	[IFLA_IPTUN_ENCAP_FLAGS]	= { .type = NLA_U16 },
1726 	[IFLA_IPTUN_ENCAP_SPORT]	= { .type = NLA_U16 },
1727 	[IFLA_IPTUN_ENCAP_DPORT]	= { .type = NLA_U16 },
1728 	[IFLA_IPTUN_FWMARK]		= { .type = NLA_U32 },
1729 };
1730 
1731 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1732 {
1733 	struct net *net = dev_net(dev);
1734 	struct sit_net *sitn = net_generic(net, sit_net_id);
1735 
1736 	if (dev != sitn->fb_tunnel_dev)
1737 		unregister_netdevice_queue(dev, head);
1738 }
1739 
1740 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1741 	.kind		= "sit",
1742 	.maxtype	= IFLA_IPTUN_MAX,
1743 	.policy		= ipip6_policy,
1744 	.priv_size	= sizeof(struct ip_tunnel),
1745 	.setup		= ipip6_tunnel_setup,
1746 	.validate	= ipip6_validate,
1747 	.newlink	= ipip6_newlink,
1748 	.changelink	= ipip6_changelink,
1749 	.get_size	= ipip6_get_size,
1750 	.fill_info	= ipip6_fill_info,
1751 	.dellink	= ipip6_dellink,
1752 	.get_link_net	= ip_tunnel_get_link_net,
1753 };
1754 
1755 static struct xfrm_tunnel sit_handler __read_mostly = {
1756 	.handler	=	ipip6_rcv,
1757 	.err_handler	=	ipip6_err,
1758 	.priority	=	1,
1759 };
1760 
1761 static struct xfrm_tunnel ipip_handler __read_mostly = {
1762 	.handler	=	ipip_rcv,
1763 	.err_handler	=	ipip6_err,
1764 	.priority	=	2,
1765 };
1766 
1767 #if IS_ENABLED(CONFIG_MPLS)
1768 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1769 	.handler	=	mplsip_rcv,
1770 	.err_handler	=	ipip6_err,
1771 	.priority	=	2,
1772 };
1773 #endif
1774 
1775 static void __net_exit sit_destroy_tunnels(struct net *net,
1776 					   struct list_head *head)
1777 {
1778 	struct sit_net *sitn = net_generic(net, sit_net_id);
1779 	struct net_device *dev, *aux;
1780 	int prio;
1781 
1782 	for_each_netdev_safe(net, dev, aux)
1783 		if (dev->rtnl_link_ops == &sit_link_ops)
1784 			unregister_netdevice_queue(dev, head);
1785 
1786 	for (prio = 1; prio < 4; prio++) {
1787 		int h;
1788 		for (h = 0; h < IP6_SIT_HASH_SIZE; h++) {
1789 			struct ip_tunnel *t;
1790 
1791 			t = rtnl_dereference(sitn->tunnels[prio][h]);
1792 			while (t) {
1793 				/* If dev is in the same netns, it has already
1794 				 * been added to the list by the previous loop.
1795 				 */
1796 				if (!net_eq(dev_net(t->dev), net))
1797 					unregister_netdevice_queue(t->dev,
1798 								   head);
1799 				t = rtnl_dereference(t->next);
1800 			}
1801 		}
1802 	}
1803 }
1804 
1805 static int __net_init sit_init_net(struct net *net)
1806 {
1807 	struct sit_net *sitn = net_generic(net, sit_net_id);
1808 	struct ip_tunnel *t;
1809 	int err;
1810 
1811 	sitn->tunnels[0] = sitn->tunnels_wc;
1812 	sitn->tunnels[1] = sitn->tunnels_l;
1813 	sitn->tunnels[2] = sitn->tunnels_r;
1814 	sitn->tunnels[3] = sitn->tunnels_r_l;
1815 
1816 	sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1817 					   NET_NAME_UNKNOWN,
1818 					   ipip6_tunnel_setup);
1819 	if (!sitn->fb_tunnel_dev) {
1820 		err = -ENOMEM;
1821 		goto err_alloc_dev;
1822 	}
1823 	dev_net_set(sitn->fb_tunnel_dev, net);
1824 	sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1825 	/* FB netdevice is special: we have one, and only one per netns.
1826 	 * Allowing to move it to another netns is clearly unsafe.
1827 	 */
1828 	sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1829 
1830 	err = register_netdev(sitn->fb_tunnel_dev);
1831 	if (err)
1832 		goto err_reg_dev;
1833 
1834 	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1835 	ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1836 
1837 	t = netdev_priv(sitn->fb_tunnel_dev);
1838 
1839 	strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1840 	return 0;
1841 
1842 err_reg_dev:
1843 	ipip6_dev_free(sitn->fb_tunnel_dev);
1844 err_alloc_dev:
1845 	return err;
1846 }
1847 
1848 static void __net_exit sit_exit_net(struct net *net)
1849 {
1850 	LIST_HEAD(list);
1851 
1852 	rtnl_lock();
1853 	sit_destroy_tunnels(net, &list);
1854 	unregister_netdevice_many(&list);
1855 	rtnl_unlock();
1856 }
1857 
1858 static struct pernet_operations sit_net_ops = {
1859 	.init = sit_init_net,
1860 	.exit = sit_exit_net,
1861 	.id   = &sit_net_id,
1862 	.size = sizeof(struct sit_net),
1863 };
1864 
1865 static void __exit sit_cleanup(void)
1866 {
1867 	rtnl_link_unregister(&sit_link_ops);
1868 	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1869 	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1870 #if IS_ENABLED(CONFIG_MPLS)
1871 	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1872 #endif
1873 
1874 	unregister_pernet_device(&sit_net_ops);
1875 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1876 }
1877 
1878 static int __init sit_init(void)
1879 {
1880 	int err;
1881 
1882 	pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1883 
1884 	err = register_pernet_device(&sit_net_ops);
1885 	if (err < 0)
1886 		return err;
1887 	err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1888 	if (err < 0) {
1889 		pr_info("%s: can't register ip6ip4\n", __func__);
1890 		goto xfrm_tunnel_failed;
1891 	}
1892 	err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1893 	if (err < 0) {
1894 		pr_info("%s: can't register ip4ip4\n", __func__);
1895 		goto xfrm_tunnel4_failed;
1896 	}
1897 #if IS_ENABLED(CONFIG_MPLS)
1898 	err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1899 	if (err < 0) {
1900 		pr_info("%s: can't register mplsip\n", __func__);
1901 		goto xfrm_tunnel_mpls_failed;
1902 	}
1903 #endif
1904 	err = rtnl_link_register(&sit_link_ops);
1905 	if (err < 0)
1906 		goto rtnl_link_failed;
1907 
1908 out:
1909 	return err;
1910 
1911 rtnl_link_failed:
1912 #if IS_ENABLED(CONFIG_MPLS)
1913 	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1914 xfrm_tunnel_mpls_failed:
1915 #endif
1916 	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1917 xfrm_tunnel4_failed:
1918 	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1919 xfrm_tunnel_failed:
1920 	unregister_pernet_device(&sit_net_ops);
1921 	goto out;
1922 }
1923 
1924 module_init(sit_init);
1925 module_exit(sit_cleanup);
1926 MODULE_LICENSE("GPL");
1927 MODULE_ALIAS_RTNL_LINK("sit");
1928 MODULE_ALIAS_NETDEV("sit0");
1929