xref: /openbmc/linux/net/ipv6/sit.c (revision adb57164)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
4  *	Linux INET6 implementation
5  *
6  *	Authors:
7  *	Pedro Roque		<roque@di.fc.ul.pt>
8  *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
9  *
10  *	Changes:
11  * Roger Venning <r.venning@telstra.com>:	6to4 support
12  * Nate Thompson <nate@thebog.net>:		6to4 support
13  * Fred Templin <fred.l.templin@boeing.com>:	isatap support
14  */
15 
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 
18 #include <linux/module.h>
19 #include <linux/capability.h>
20 #include <linux/errno.h>
21 #include <linux/types.h>
22 #include <linux/socket.h>
23 #include <linux/sockios.h>
24 #include <linux/net.h>
25 #include <linux/in6.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_arp.h>
28 #include <linux/icmp.h>
29 #include <linux/slab.h>
30 #include <linux/uaccess.h>
31 #include <linux/init.h>
32 #include <linux/netfilter_ipv4.h>
33 #include <linux/if_ether.h>
34 
35 #include <net/sock.h>
36 #include <net/snmp.h>
37 
38 #include <net/ipv6.h>
39 #include <net/protocol.h>
40 #include <net/transp_v6.h>
41 #include <net/ip6_fib.h>
42 #include <net/ip6_route.h>
43 #include <net/ndisc.h>
44 #include <net/addrconf.h>
45 #include <net/ip.h>
46 #include <net/udp.h>
47 #include <net/icmp.h>
48 #include <net/ip_tunnels.h>
49 #include <net/inet_ecn.h>
50 #include <net/xfrm.h>
51 #include <net/dsfield.h>
52 #include <net/net_namespace.h>
53 #include <net/netns/generic.h>
54 
55 /*
56    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
57 
58    For comments look at net/ipv4/ip_gre.c --ANK
59  */
60 
61 #define IP6_SIT_HASH_SIZE  16
62 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
63 
64 static bool log_ecn_error = true;
65 module_param(log_ecn_error, bool, 0644);
66 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
67 
68 static int ipip6_tunnel_init(struct net_device *dev);
69 static void ipip6_tunnel_setup(struct net_device *dev);
70 static void ipip6_dev_free(struct net_device *dev);
71 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
72 		      __be32 *v4dst);
73 static struct rtnl_link_ops sit_link_ops __read_mostly;
74 
75 static unsigned int sit_net_id __read_mostly;
76 struct sit_net {
77 	struct ip_tunnel __rcu *tunnels_r_l[IP6_SIT_HASH_SIZE];
78 	struct ip_tunnel __rcu *tunnels_r[IP6_SIT_HASH_SIZE];
79 	struct ip_tunnel __rcu *tunnels_l[IP6_SIT_HASH_SIZE];
80 	struct ip_tunnel __rcu *tunnels_wc[1];
81 	struct ip_tunnel __rcu **tunnels[4];
82 
83 	struct net_device *fb_tunnel_dev;
84 };
85 
86 /*
87  * Must be invoked with rcu_read_lock
88  */
89 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
90 					     struct net_device *dev,
91 					     __be32 remote, __be32 local,
92 					     int sifindex)
93 {
94 	unsigned int h0 = HASH(remote);
95 	unsigned int h1 = HASH(local);
96 	struct ip_tunnel *t;
97 	struct sit_net *sitn = net_generic(net, sit_net_id);
98 	int ifindex = dev ? dev->ifindex : 0;
99 
100 	for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
101 		if (local == t->parms.iph.saddr &&
102 		    remote == t->parms.iph.daddr &&
103 		    (!dev || !t->parms.link || ifindex == t->parms.link ||
104 		     sifindex == 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 || ifindex == t->parms.link ||
111 		     sifindex == t->parms.link) &&
112 		    (t->dev->flags & IFF_UP))
113 			return t;
114 	}
115 	for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
116 		if (local == t->parms.iph.saddr &&
117 		    (!dev || !t->parms.link || ifindex == t->parms.link ||
118 		     sifindex == t->parms.link) &&
119 		    (t->dev->flags & IFF_UP))
120 			return t;
121 	}
122 	t = rcu_dereference(sitn->tunnels_wc[0]);
123 	if (t && (t->dev->flags & IFF_UP))
124 		return t;
125 	return NULL;
126 }
127 
128 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
129 		struct ip_tunnel_parm *parms)
130 {
131 	__be32 remote = parms->iph.daddr;
132 	__be32 local = parms->iph.saddr;
133 	unsigned int h = 0;
134 	int prio = 0;
135 
136 	if (remote) {
137 		prio |= 2;
138 		h ^= HASH(remote);
139 	}
140 	if (local) {
141 		prio |= 1;
142 		h ^= HASH(local);
143 	}
144 	return &sitn->tunnels[prio][h];
145 }
146 
147 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
148 		struct ip_tunnel *t)
149 {
150 	return __ipip6_bucket(sitn, &t->parms);
151 }
152 
153 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
154 {
155 	struct ip_tunnel __rcu **tp;
156 	struct ip_tunnel *iter;
157 
158 	for (tp = ipip6_bucket(sitn, t);
159 	     (iter = rtnl_dereference(*tp)) != NULL;
160 	     tp = &iter->next) {
161 		if (t == iter) {
162 			rcu_assign_pointer(*tp, t->next);
163 			break;
164 		}
165 	}
166 }
167 
168 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
169 {
170 	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
171 
172 	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
173 	rcu_assign_pointer(*tp, t);
174 }
175 
176 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
177 {
178 #ifdef CONFIG_IPV6_SIT_6RD
179 	struct ip_tunnel *t = netdev_priv(dev);
180 
181 	if (dev == sitn->fb_tunnel_dev || !sitn->fb_tunnel_dev) {
182 		ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
183 		t->ip6rd.relay_prefix = 0;
184 		t->ip6rd.prefixlen = 16;
185 		t->ip6rd.relay_prefixlen = 0;
186 	} else {
187 		struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
188 		memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
189 	}
190 #endif
191 }
192 
193 static int ipip6_tunnel_create(struct net_device *dev)
194 {
195 	struct ip_tunnel *t = netdev_priv(dev);
196 	struct net *net = dev_net(dev);
197 	struct sit_net *sitn = net_generic(net, sit_net_id);
198 	int err;
199 
200 	memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
201 	memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
202 
203 	if ((__force u16)t->parms.i_flags & SIT_ISATAP)
204 		dev->priv_flags |= IFF_ISATAP;
205 
206 	dev->rtnl_link_ops = &sit_link_ops;
207 
208 	err = register_netdevice(dev);
209 	if (err < 0)
210 		goto out;
211 
212 	ipip6_tunnel_clone_6rd(dev, sitn);
213 
214 	dev_hold(dev);
215 
216 	ipip6_tunnel_link(sitn, t);
217 	return 0;
218 
219 out:
220 	return err;
221 }
222 
223 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
224 		struct ip_tunnel_parm *parms, int create)
225 {
226 	__be32 remote = parms->iph.daddr;
227 	__be32 local = parms->iph.saddr;
228 	struct ip_tunnel *t, *nt;
229 	struct ip_tunnel __rcu **tp;
230 	struct net_device *dev;
231 	char name[IFNAMSIZ];
232 	struct sit_net *sitn = net_generic(net, sit_net_id);
233 
234 	for (tp = __ipip6_bucket(sitn, parms);
235 	    (t = rtnl_dereference(*tp)) != NULL;
236 	     tp = &t->next) {
237 		if (local == t->parms.iph.saddr &&
238 		    remote == t->parms.iph.daddr &&
239 		    parms->link == t->parms.link) {
240 			if (create)
241 				return NULL;
242 			else
243 				return t;
244 		}
245 	}
246 	if (!create)
247 		goto failed;
248 
249 	if (parms->name[0]) {
250 		if (!dev_valid_name(parms->name))
251 			goto failed;
252 		strlcpy(name, parms->name, IFNAMSIZ);
253 	} else {
254 		strcpy(name, "sit%d");
255 	}
256 	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
257 			   ipip6_tunnel_setup);
258 	if (!dev)
259 		return NULL;
260 
261 	dev_net_set(dev, net);
262 
263 	nt = netdev_priv(dev);
264 
265 	nt->parms = *parms;
266 	if (ipip6_tunnel_create(dev) < 0)
267 		goto failed_free;
268 
269 	return nt;
270 
271 failed_free:
272 	free_netdev(dev);
273 failed:
274 	return NULL;
275 }
276 
277 #define for_each_prl_rcu(start)			\
278 	for (prl = rcu_dereference(start);	\
279 	     prl;				\
280 	     prl = rcu_dereference(prl->next))
281 
282 static struct ip_tunnel_prl_entry *
283 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
284 {
285 	struct ip_tunnel_prl_entry *prl;
286 
287 	for_each_prl_rcu(t->prl)
288 		if (prl->addr == addr)
289 			break;
290 	return prl;
291 
292 }
293 
294 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
295 				struct ip_tunnel_prl __user *a)
296 {
297 	struct ip_tunnel_prl kprl, *kp;
298 	struct ip_tunnel_prl_entry *prl;
299 	unsigned int cmax, c = 0, ca, len;
300 	int ret = 0;
301 
302 	if (copy_from_user(&kprl, a, sizeof(kprl)))
303 		return -EFAULT;
304 	cmax = kprl.datalen / sizeof(kprl);
305 	if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
306 		cmax = 1;
307 
308 	/* For simple GET or for root users,
309 	 * we try harder to allocate.
310 	 */
311 	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
312 		kcalloc(cmax, sizeof(*kp), GFP_KERNEL | __GFP_NOWARN) :
313 		NULL;
314 
315 	rcu_read_lock();
316 
317 	ca = t->prl_count < cmax ? t->prl_count : cmax;
318 
319 	if (!kp) {
320 		/* We don't try hard to allocate much memory for
321 		 * non-root users.
322 		 * For root users, retry allocating enough memory for
323 		 * the answer.
324 		 */
325 		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
326 		if (!kp) {
327 			ret = -ENOMEM;
328 			goto out;
329 		}
330 	}
331 
332 	c = 0;
333 	for_each_prl_rcu(t->prl) {
334 		if (c >= cmax)
335 			break;
336 		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
337 			continue;
338 		kp[c].addr = prl->addr;
339 		kp[c].flags = prl->flags;
340 		c++;
341 		if (kprl.addr != htonl(INADDR_ANY))
342 			break;
343 	}
344 out:
345 	rcu_read_unlock();
346 
347 	len = sizeof(*kp) * c;
348 	ret = 0;
349 	if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
350 		ret = -EFAULT;
351 
352 	kfree(kp);
353 
354 	return ret;
355 }
356 
357 static int
358 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
359 {
360 	struct ip_tunnel_prl_entry *p;
361 	int err = 0;
362 
363 	if (a->addr == htonl(INADDR_ANY))
364 		return -EINVAL;
365 
366 	ASSERT_RTNL();
367 
368 	for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
369 		if (p->addr == a->addr) {
370 			if (chg) {
371 				p->flags = a->flags;
372 				goto out;
373 			}
374 			err = -EEXIST;
375 			goto out;
376 		}
377 	}
378 
379 	if (chg) {
380 		err = -ENXIO;
381 		goto out;
382 	}
383 
384 	p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
385 	if (!p) {
386 		err = -ENOBUFS;
387 		goto out;
388 	}
389 
390 	p->next = t->prl;
391 	p->addr = a->addr;
392 	p->flags = a->flags;
393 	t->prl_count++;
394 	rcu_assign_pointer(t->prl, p);
395 out:
396 	return err;
397 }
398 
399 static void prl_list_destroy_rcu(struct rcu_head *head)
400 {
401 	struct ip_tunnel_prl_entry *p, *n;
402 
403 	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
404 	do {
405 		n = rcu_dereference_protected(p->next, 1);
406 		kfree(p);
407 		p = n;
408 	} while (p);
409 }
410 
411 static int
412 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
413 {
414 	struct ip_tunnel_prl_entry *x;
415 	struct ip_tunnel_prl_entry __rcu **p;
416 	int err = 0;
417 
418 	ASSERT_RTNL();
419 
420 	if (a && a->addr != htonl(INADDR_ANY)) {
421 		for (p = &t->prl;
422 		     (x = rtnl_dereference(*p)) != NULL;
423 		     p = &x->next) {
424 			if (x->addr == a->addr) {
425 				*p = x->next;
426 				kfree_rcu(x, rcu_head);
427 				t->prl_count--;
428 				goto out;
429 			}
430 		}
431 		err = -ENXIO;
432 	} else {
433 		x = rtnl_dereference(t->prl);
434 		if (x) {
435 			t->prl_count = 0;
436 			call_rcu(&x->rcu_head, prl_list_destroy_rcu);
437 			t->prl = NULL;
438 		}
439 	}
440 out:
441 	return err;
442 }
443 
444 static int
445 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
446 {
447 	struct ip_tunnel_prl_entry *p;
448 	int ok = 1;
449 
450 	rcu_read_lock();
451 	p = __ipip6_tunnel_locate_prl(t, iph->saddr);
452 	if (p) {
453 		if (p->flags & PRL_DEFAULT)
454 			skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
455 		else
456 			skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
457 	} else {
458 		const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
459 
460 		if (ipv6_addr_is_isatap(addr6) &&
461 		    (addr6->s6_addr32[3] == iph->saddr) &&
462 		    ipv6_chk_prefix(addr6, t->dev))
463 			skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
464 		else
465 			ok = 0;
466 	}
467 	rcu_read_unlock();
468 	return ok;
469 }
470 
471 static void ipip6_tunnel_uninit(struct net_device *dev)
472 {
473 	struct ip_tunnel *tunnel = netdev_priv(dev);
474 	struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
475 
476 	if (dev == sitn->fb_tunnel_dev) {
477 		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
478 	} else {
479 		ipip6_tunnel_unlink(sitn, tunnel);
480 		ipip6_tunnel_del_prl(tunnel, NULL);
481 	}
482 	dst_cache_reset(&tunnel->dst_cache);
483 	dev_put(dev);
484 }
485 
486 static int ipip6_err(struct sk_buff *skb, u32 info)
487 {
488 	const struct iphdr *iph = (const struct iphdr *)skb->data;
489 	const int type = icmp_hdr(skb)->type;
490 	const int code = icmp_hdr(skb)->code;
491 	unsigned int data_len = 0;
492 	struct ip_tunnel *t;
493 	int sifindex;
494 	int err;
495 
496 	switch (type) {
497 	default:
498 	case ICMP_PARAMETERPROB:
499 		return 0;
500 
501 	case ICMP_DEST_UNREACH:
502 		switch (code) {
503 		case ICMP_SR_FAILED:
504 			/* Impossible event. */
505 			return 0;
506 		default:
507 			/* All others are translated to HOST_UNREACH.
508 			   rfc2003 contains "deep thoughts" about NET_UNREACH,
509 			   I believe they are just ether pollution. --ANK
510 			 */
511 			break;
512 		}
513 		break;
514 	case ICMP_TIME_EXCEEDED:
515 		if (code != ICMP_EXC_TTL)
516 			return 0;
517 		data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
518 		break;
519 	case ICMP_REDIRECT:
520 		break;
521 	}
522 
523 	err = -ENOENT;
524 
525 	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
526 	t = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
527 				iph->daddr, iph->saddr, sifindex);
528 	if (!t)
529 		goto out;
530 
531 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
532 		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
533 				 t->parms.link, iph->protocol);
534 		err = 0;
535 		goto out;
536 	}
537 	if (type == ICMP_REDIRECT) {
538 		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
539 			      iph->protocol);
540 		err = 0;
541 		goto out;
542 	}
543 
544 	err = 0;
545 	if (__in6_dev_get(skb->dev) &&
546 	    !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
547 		goto out;
548 
549 	if (t->parms.iph.daddr == 0)
550 		goto out;
551 
552 	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
553 		goto out;
554 
555 	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
556 		t->err_count++;
557 	else
558 		t->err_count = 1;
559 	t->err_time = jiffies;
560 out:
561 	return err;
562 }
563 
564 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
565 				  const struct in6_addr *v6addr)
566 {
567 	__be32 v4embed = 0;
568 	if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
569 		return true;
570 	return false;
571 }
572 
573 /* Checks if an address matches an address on the tunnel interface.
574  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
575  * Long story:
576  * This function is called after we considered the packet as spoofed
577  * in is_spoofed_6rd.
578  * We may have a router that is doing NAT for proto 41 packets
579  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
580  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
581  * function will return true, dropping the packet.
582  * But, we can still check if is spoofed against the IP
583  * addresses associated with the interface.
584  */
585 static bool only_dnatted(const struct ip_tunnel *tunnel,
586 	const struct in6_addr *v6dst)
587 {
588 	int prefix_len;
589 
590 #ifdef CONFIG_IPV6_SIT_6RD
591 	prefix_len = tunnel->ip6rd.prefixlen + 32
592 		- tunnel->ip6rd.relay_prefixlen;
593 #else
594 	prefix_len = 48;
595 #endif
596 	return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
597 }
598 
599 /* Returns true if a packet is spoofed */
600 static bool packet_is_spoofed(struct sk_buff *skb,
601 			      const struct iphdr *iph,
602 			      struct ip_tunnel *tunnel)
603 {
604 	const struct ipv6hdr *ipv6h;
605 
606 	if (tunnel->dev->priv_flags & IFF_ISATAP) {
607 		if (!isatap_chksrc(skb, iph, tunnel))
608 			return true;
609 
610 		return false;
611 	}
612 
613 	if (tunnel->dev->flags & IFF_POINTOPOINT)
614 		return false;
615 
616 	ipv6h = ipv6_hdr(skb);
617 
618 	if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
619 		net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
620 				     &iph->saddr, &ipv6h->saddr,
621 				     &iph->daddr, &ipv6h->daddr);
622 		return true;
623 	}
624 
625 	if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
626 		return false;
627 
628 	if (only_dnatted(tunnel, &ipv6h->daddr))
629 		return false;
630 
631 	net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
632 			     &iph->saddr, &ipv6h->saddr,
633 			     &iph->daddr, &ipv6h->daddr);
634 	return true;
635 }
636 
637 static int ipip6_rcv(struct sk_buff *skb)
638 {
639 	const struct iphdr *iph = ip_hdr(skb);
640 	struct ip_tunnel *tunnel;
641 	int sifindex;
642 	int err;
643 
644 	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
645 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
646 				     iph->saddr, iph->daddr, sifindex);
647 	if (tunnel) {
648 		struct pcpu_sw_netstats *tstats;
649 
650 		if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
651 		    tunnel->parms.iph.protocol != 0)
652 			goto out;
653 
654 		skb->mac_header = skb->network_header;
655 		skb_reset_network_header(skb);
656 		IPCB(skb)->flags = 0;
657 		skb->dev = tunnel->dev;
658 
659 		if (packet_is_spoofed(skb, iph, tunnel)) {
660 			tunnel->dev->stats.rx_errors++;
661 			goto out;
662 		}
663 
664 		if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
665 		    !net_eq(tunnel->net, dev_net(tunnel->dev))))
666 			goto out;
667 
668 		/* skb can be uncloned in iptunnel_pull_header, so
669 		 * old iph is no longer valid
670 		 */
671 		iph = (const struct iphdr *)skb_mac_header(skb);
672 		err = IP_ECN_decapsulate(iph, skb);
673 		if (unlikely(err)) {
674 			if (log_ecn_error)
675 				net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
676 						     &iph->saddr, iph->tos);
677 			if (err > 1) {
678 				++tunnel->dev->stats.rx_frame_errors;
679 				++tunnel->dev->stats.rx_errors;
680 				goto out;
681 			}
682 		}
683 
684 		tstats = this_cpu_ptr(tunnel->dev->tstats);
685 		u64_stats_update_begin(&tstats->syncp);
686 		tstats->rx_packets++;
687 		tstats->rx_bytes += skb->len;
688 		u64_stats_update_end(&tstats->syncp);
689 
690 		netif_rx(skb);
691 
692 		return 0;
693 	}
694 
695 	/* no tunnel matched,  let upstream know, ipsec may handle it */
696 	return 1;
697 out:
698 	kfree_skb(skb);
699 	return 0;
700 }
701 
702 static const struct tnl_ptk_info ipip_tpi = {
703 	/* no tunnel info required for ipip. */
704 	.proto = htons(ETH_P_IP),
705 };
706 
707 #if IS_ENABLED(CONFIG_MPLS)
708 static const struct tnl_ptk_info mplsip_tpi = {
709 	/* no tunnel info required for mplsip. */
710 	.proto = htons(ETH_P_MPLS_UC),
711 };
712 #endif
713 
714 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
715 {
716 	const struct iphdr *iph;
717 	struct ip_tunnel *tunnel;
718 	int sifindex;
719 
720 	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
721 
722 	iph = ip_hdr(skb);
723 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
724 				     iph->saddr, iph->daddr, sifindex);
725 	if (tunnel) {
726 		const struct tnl_ptk_info *tpi;
727 
728 		if (tunnel->parms.iph.protocol != ipproto &&
729 		    tunnel->parms.iph.protocol != 0)
730 			goto drop;
731 
732 		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
733 			goto drop;
734 #if IS_ENABLED(CONFIG_MPLS)
735 		if (ipproto == IPPROTO_MPLS)
736 			tpi = &mplsip_tpi;
737 		else
738 #endif
739 			tpi = &ipip_tpi;
740 		if (iptunnel_pull_header(skb, 0, tpi->proto, false))
741 			goto drop;
742 		return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
743 	}
744 
745 	return 1;
746 
747 drop:
748 	kfree_skb(skb);
749 	return 0;
750 }
751 
752 static int ipip_rcv(struct sk_buff *skb)
753 {
754 	return sit_tunnel_rcv(skb, IPPROTO_IPIP);
755 }
756 
757 #if IS_ENABLED(CONFIG_MPLS)
758 static int mplsip_rcv(struct sk_buff *skb)
759 {
760 	return sit_tunnel_rcv(skb, IPPROTO_MPLS);
761 }
762 #endif
763 
764 /*
765  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
766  * stores the embedded IPv4 address in v4dst and returns true.
767  */
768 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
769 		      __be32 *v4dst)
770 {
771 #ifdef CONFIG_IPV6_SIT_6RD
772 	if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
773 			      tunnel->ip6rd.prefixlen)) {
774 		unsigned int pbw0, pbi0;
775 		int pbi1;
776 		u32 d;
777 
778 		pbw0 = tunnel->ip6rd.prefixlen >> 5;
779 		pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
780 
781 		d = tunnel->ip6rd.relay_prefixlen < 32 ?
782 			(ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
783 		    tunnel->ip6rd.relay_prefixlen : 0;
784 
785 		pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
786 		if (pbi1 > 0)
787 			d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
788 			     (32 - pbi1);
789 
790 		*v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
791 		return true;
792 	}
793 #else
794 	if (v6dst->s6_addr16[0] == htons(0x2002)) {
795 		/* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
796 		memcpy(v4dst, &v6dst->s6_addr16[1], 4);
797 		return true;
798 	}
799 #endif
800 	return false;
801 }
802 
803 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
804 			     const struct in6_addr *v6dst)
805 {
806 	__be32 dst = 0;
807 	check_6rd(tunnel, v6dst, &dst);
808 	return dst;
809 }
810 
811 /*
812  *	This function assumes it is being called from dev_queue_xmit()
813  *	and that skb is filled properly by that function.
814  */
815 
816 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
817 				     struct net_device *dev)
818 {
819 	struct ip_tunnel *tunnel = netdev_priv(dev);
820 	const struct iphdr  *tiph = &tunnel->parms.iph;
821 	const struct ipv6hdr *iph6 = ipv6_hdr(skb);
822 	u8     tos = tunnel->parms.iph.tos;
823 	__be16 df = tiph->frag_off;
824 	struct rtable *rt;		/* Route to the other host */
825 	struct net_device *tdev;	/* Device to other host */
826 	unsigned int max_headroom;	/* The extra header space needed */
827 	__be32 dst = tiph->daddr;
828 	struct flowi4 fl4;
829 	int    mtu;
830 	const struct in6_addr *addr6;
831 	int addr_type;
832 	u8 ttl;
833 	u8 protocol = IPPROTO_IPV6;
834 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
835 
836 	if (tos == 1)
837 		tos = ipv6_get_dsfield(iph6);
838 
839 	/* ISATAP (RFC4214) - must come before 6to4 */
840 	if (dev->priv_flags & IFF_ISATAP) {
841 		struct neighbour *neigh = NULL;
842 		bool do_tx_error = false;
843 
844 		if (skb_dst(skb))
845 			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
846 
847 		if (!neigh) {
848 			net_dbg_ratelimited("nexthop == NULL\n");
849 			goto tx_error;
850 		}
851 
852 		addr6 = (const struct in6_addr *)&neigh->primary_key;
853 		addr_type = ipv6_addr_type(addr6);
854 
855 		if ((addr_type & IPV6_ADDR_UNICAST) &&
856 		     ipv6_addr_is_isatap(addr6))
857 			dst = addr6->s6_addr32[3];
858 		else
859 			do_tx_error = true;
860 
861 		neigh_release(neigh);
862 		if (do_tx_error)
863 			goto tx_error;
864 	}
865 
866 	if (!dst)
867 		dst = try_6rd(tunnel, &iph6->daddr);
868 
869 	if (!dst) {
870 		struct neighbour *neigh = NULL;
871 		bool do_tx_error = false;
872 
873 		if (skb_dst(skb))
874 			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
875 
876 		if (!neigh) {
877 			net_dbg_ratelimited("nexthop == NULL\n");
878 			goto tx_error;
879 		}
880 
881 		addr6 = (const struct in6_addr *)&neigh->primary_key;
882 		addr_type = ipv6_addr_type(addr6);
883 
884 		if (addr_type == IPV6_ADDR_ANY) {
885 			addr6 = &ipv6_hdr(skb)->daddr;
886 			addr_type = ipv6_addr_type(addr6);
887 		}
888 
889 		if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
890 			dst = addr6->s6_addr32[3];
891 		else
892 			do_tx_error = true;
893 
894 		neigh_release(neigh);
895 		if (do_tx_error)
896 			goto tx_error;
897 	}
898 
899 	flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
900 			   RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
901 			   0, dst, tiph->saddr, 0, 0,
902 			   sock_net_uid(tunnel->net, NULL));
903 
904 	rt = dst_cache_get_ip4(&tunnel->dst_cache, &fl4.saddr);
905 	if (!rt) {
906 		rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
907 		if (IS_ERR(rt)) {
908 			dev->stats.tx_carrier_errors++;
909 			goto tx_error_icmp;
910 		}
911 		dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr);
912 	}
913 
914 	if (rt->rt_type != RTN_UNICAST) {
915 		ip_rt_put(rt);
916 		dev->stats.tx_carrier_errors++;
917 		goto tx_error_icmp;
918 	}
919 	tdev = rt->dst.dev;
920 
921 	if (tdev == dev) {
922 		ip_rt_put(rt);
923 		dev->stats.collisions++;
924 		goto tx_error;
925 	}
926 
927 	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
928 		ip_rt_put(rt);
929 		goto tx_error;
930 	}
931 
932 	if (df) {
933 		mtu = dst_mtu(&rt->dst) - t_hlen;
934 
935 		if (mtu < 68) {
936 			dev->stats.collisions++;
937 			ip_rt_put(rt);
938 			goto tx_error;
939 		}
940 
941 		if (mtu < IPV6_MIN_MTU) {
942 			mtu = IPV6_MIN_MTU;
943 			df = 0;
944 		}
945 
946 		if (tunnel->parms.iph.daddr)
947 			skb_dst_update_pmtu_no_confirm(skb, mtu);
948 
949 		if (skb->len > mtu && !skb_is_gso(skb)) {
950 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
951 			ip_rt_put(rt);
952 			goto tx_error;
953 		}
954 	}
955 
956 	if (tunnel->err_count > 0) {
957 		if (time_before(jiffies,
958 				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
959 			tunnel->err_count--;
960 			dst_link_failure(skb);
961 		} else
962 			tunnel->err_count = 0;
963 	}
964 
965 	/*
966 	 * Okay, now see if we can stuff it in the buffer as-is.
967 	 */
968 	max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
969 
970 	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
971 	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
972 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
973 		if (!new_skb) {
974 			ip_rt_put(rt);
975 			dev->stats.tx_dropped++;
976 			kfree_skb(skb);
977 			return NETDEV_TX_OK;
978 		}
979 		if (skb->sk)
980 			skb_set_owner_w(new_skb, skb->sk);
981 		dev_kfree_skb(skb);
982 		skb = new_skb;
983 		iph6 = ipv6_hdr(skb);
984 	}
985 	ttl = tiph->ttl;
986 	if (ttl == 0)
987 		ttl = iph6->hop_limit;
988 	tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
989 
990 	if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
991 		ip_rt_put(rt);
992 		goto tx_error;
993 	}
994 
995 	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
996 
997 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
998 		      df, !net_eq(tunnel->net, dev_net(dev)));
999 	return NETDEV_TX_OK;
1000 
1001 tx_error_icmp:
1002 	dst_link_failure(skb);
1003 tx_error:
1004 	kfree_skb(skb);
1005 	dev->stats.tx_errors++;
1006 	return NETDEV_TX_OK;
1007 }
1008 
1009 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
1010 				     struct net_device *dev, u8 ipproto)
1011 {
1012 	struct ip_tunnel *tunnel = netdev_priv(dev);
1013 	const struct iphdr  *tiph = &tunnel->parms.iph;
1014 
1015 	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1016 		goto tx_error;
1017 
1018 	skb_set_inner_ipproto(skb, ipproto);
1019 
1020 	ip_tunnel_xmit(skb, dev, tiph, ipproto);
1021 	return NETDEV_TX_OK;
1022 tx_error:
1023 	kfree_skb(skb);
1024 	dev->stats.tx_errors++;
1025 	return NETDEV_TX_OK;
1026 }
1027 
1028 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1029 				   struct net_device *dev)
1030 {
1031 	if (!pskb_inet_may_pull(skb))
1032 		goto tx_err;
1033 
1034 	switch (skb->protocol) {
1035 	case htons(ETH_P_IP):
1036 		sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1037 		break;
1038 	case htons(ETH_P_IPV6):
1039 		ipip6_tunnel_xmit(skb, dev);
1040 		break;
1041 #if IS_ENABLED(CONFIG_MPLS)
1042 	case htons(ETH_P_MPLS_UC):
1043 		sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1044 		break;
1045 #endif
1046 	default:
1047 		goto tx_err;
1048 	}
1049 
1050 	return NETDEV_TX_OK;
1051 
1052 tx_err:
1053 	dev->stats.tx_errors++;
1054 	kfree_skb(skb);
1055 	return NETDEV_TX_OK;
1056 
1057 }
1058 
1059 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1060 {
1061 	struct net_device *tdev = NULL;
1062 	struct ip_tunnel *tunnel;
1063 	const struct iphdr *iph;
1064 	struct flowi4 fl4;
1065 
1066 	tunnel = netdev_priv(dev);
1067 	iph = &tunnel->parms.iph;
1068 
1069 	if (iph->daddr) {
1070 		struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1071 							  NULL,
1072 							  iph->daddr, iph->saddr,
1073 							  0, 0,
1074 							  IPPROTO_IPV6,
1075 							  RT_TOS(iph->tos),
1076 							  tunnel->parms.link);
1077 
1078 		if (!IS_ERR(rt)) {
1079 			tdev = rt->dst.dev;
1080 			ip_rt_put(rt);
1081 		}
1082 		dev->flags |= IFF_POINTOPOINT;
1083 	}
1084 
1085 	if (!tdev && tunnel->parms.link)
1086 		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1087 
1088 	if (tdev && !netif_is_l3_master(tdev)) {
1089 		int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1090 
1091 		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1092 		dev->mtu = tdev->mtu - t_hlen;
1093 		if (dev->mtu < IPV6_MIN_MTU)
1094 			dev->mtu = IPV6_MIN_MTU;
1095 	}
1096 }
1097 
1098 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
1099 				__u32 fwmark)
1100 {
1101 	struct net *net = t->net;
1102 	struct sit_net *sitn = net_generic(net, sit_net_id);
1103 
1104 	ipip6_tunnel_unlink(sitn, t);
1105 	synchronize_net();
1106 	t->parms.iph.saddr = p->iph.saddr;
1107 	t->parms.iph.daddr = p->iph.daddr;
1108 	memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1109 	memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1110 	ipip6_tunnel_link(sitn, t);
1111 	t->parms.iph.ttl = p->iph.ttl;
1112 	t->parms.iph.tos = p->iph.tos;
1113 	t->parms.iph.frag_off = p->iph.frag_off;
1114 	if (t->parms.link != p->link || t->fwmark != fwmark) {
1115 		t->parms.link = p->link;
1116 		t->fwmark = fwmark;
1117 		ipip6_tunnel_bind_dev(t->dev);
1118 	}
1119 	dst_cache_reset(&t->dst_cache);
1120 	netdev_state_change(t->dev);
1121 }
1122 
1123 #ifdef CONFIG_IPV6_SIT_6RD
1124 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1125 				   struct ip_tunnel_6rd *ip6rd)
1126 {
1127 	struct in6_addr prefix;
1128 	__be32 relay_prefix;
1129 
1130 	if (ip6rd->relay_prefixlen > 32 ||
1131 	    ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1132 		return -EINVAL;
1133 
1134 	ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1135 	if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1136 		return -EINVAL;
1137 	if (ip6rd->relay_prefixlen)
1138 		relay_prefix = ip6rd->relay_prefix &
1139 			       htonl(0xffffffffUL <<
1140 				     (32 - ip6rd->relay_prefixlen));
1141 	else
1142 		relay_prefix = 0;
1143 	if (relay_prefix != ip6rd->relay_prefix)
1144 		return -EINVAL;
1145 
1146 	t->ip6rd.prefix = prefix;
1147 	t->ip6rd.relay_prefix = relay_prefix;
1148 	t->ip6rd.prefixlen = ip6rd->prefixlen;
1149 	t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1150 	dst_cache_reset(&t->dst_cache);
1151 	netdev_state_change(t->dev);
1152 	return 0;
1153 }
1154 #endif
1155 
1156 static bool ipip6_valid_ip_proto(u8 ipproto)
1157 {
1158 	return ipproto == IPPROTO_IPV6 ||
1159 		ipproto == IPPROTO_IPIP ||
1160 #if IS_ENABLED(CONFIG_MPLS)
1161 		ipproto == IPPROTO_MPLS ||
1162 #endif
1163 		ipproto == 0;
1164 }
1165 
1166 static int
1167 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1168 {
1169 	int err = 0;
1170 	struct ip_tunnel_parm p;
1171 	struct ip_tunnel_prl prl;
1172 	struct ip_tunnel *t = netdev_priv(dev);
1173 	struct net *net = t->net;
1174 	struct sit_net *sitn = net_generic(net, sit_net_id);
1175 #ifdef CONFIG_IPV6_SIT_6RD
1176 	struct ip_tunnel_6rd ip6rd;
1177 #endif
1178 
1179 	switch (cmd) {
1180 	case SIOCGETTUNNEL:
1181 #ifdef CONFIG_IPV6_SIT_6RD
1182 	case SIOCGET6RD:
1183 #endif
1184 		if (dev == sitn->fb_tunnel_dev) {
1185 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1186 				err = -EFAULT;
1187 				break;
1188 			}
1189 			t = ipip6_tunnel_locate(net, &p, 0);
1190 			if (!t)
1191 				t = netdev_priv(dev);
1192 		}
1193 
1194 		err = -EFAULT;
1195 		if (cmd == SIOCGETTUNNEL) {
1196 			memcpy(&p, &t->parms, sizeof(p));
1197 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1198 					 sizeof(p)))
1199 				goto done;
1200 #ifdef CONFIG_IPV6_SIT_6RD
1201 		} else {
1202 			ip6rd.prefix = t->ip6rd.prefix;
1203 			ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1204 			ip6rd.prefixlen = t->ip6rd.prefixlen;
1205 			ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1206 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1207 					 sizeof(ip6rd)))
1208 				goto done;
1209 #endif
1210 		}
1211 		err = 0;
1212 		break;
1213 
1214 	case SIOCADDTUNNEL:
1215 	case SIOCCHGTUNNEL:
1216 		err = -EPERM;
1217 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1218 			goto done;
1219 
1220 		err = -EFAULT;
1221 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1222 			goto done;
1223 
1224 		err = -EINVAL;
1225 		if (!ipip6_valid_ip_proto(p.iph.protocol))
1226 			goto done;
1227 		if (p.iph.version != 4 ||
1228 		    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1229 			goto done;
1230 		if (p.iph.ttl)
1231 			p.iph.frag_off |= htons(IP_DF);
1232 
1233 		t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1234 
1235 		if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1236 			if (t) {
1237 				if (t->dev != dev) {
1238 					err = -EEXIST;
1239 					break;
1240 				}
1241 			} else {
1242 				if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1243 				    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1244 					err = -EINVAL;
1245 					break;
1246 				}
1247 				t = netdev_priv(dev);
1248 			}
1249 
1250 			ipip6_tunnel_update(t, &p, t->fwmark);
1251 		}
1252 
1253 		if (t) {
1254 			err = 0;
1255 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1256 				err = -EFAULT;
1257 		} else
1258 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1259 		break;
1260 
1261 	case SIOCDELTUNNEL:
1262 		err = -EPERM;
1263 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1264 			goto done;
1265 
1266 		if (dev == sitn->fb_tunnel_dev) {
1267 			err = -EFAULT;
1268 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1269 				goto done;
1270 			err = -ENOENT;
1271 			t = ipip6_tunnel_locate(net, &p, 0);
1272 			if (!t)
1273 				goto done;
1274 			err = -EPERM;
1275 			if (t == netdev_priv(sitn->fb_tunnel_dev))
1276 				goto done;
1277 			dev = t->dev;
1278 		}
1279 		unregister_netdevice(dev);
1280 		err = 0;
1281 		break;
1282 
1283 	case SIOCGETPRL:
1284 		err = -EINVAL;
1285 		if (dev == sitn->fb_tunnel_dev)
1286 			goto done;
1287 		err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1288 		break;
1289 
1290 	case SIOCADDPRL:
1291 	case SIOCDELPRL:
1292 	case SIOCCHGPRL:
1293 		err = -EPERM;
1294 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1295 			goto done;
1296 		err = -EINVAL;
1297 		if (dev == sitn->fb_tunnel_dev)
1298 			goto done;
1299 		err = -EFAULT;
1300 		if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1301 			goto done;
1302 
1303 		switch (cmd) {
1304 		case SIOCDELPRL:
1305 			err = ipip6_tunnel_del_prl(t, &prl);
1306 			break;
1307 		case SIOCADDPRL:
1308 		case SIOCCHGPRL:
1309 			err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1310 			break;
1311 		}
1312 		dst_cache_reset(&t->dst_cache);
1313 		netdev_state_change(dev);
1314 		break;
1315 
1316 #ifdef CONFIG_IPV6_SIT_6RD
1317 	case SIOCADD6RD:
1318 	case SIOCCHG6RD:
1319 	case SIOCDEL6RD:
1320 		err = -EPERM;
1321 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1322 			goto done;
1323 
1324 		err = -EFAULT;
1325 		if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1326 				   sizeof(ip6rd)))
1327 			goto done;
1328 
1329 		if (cmd != SIOCDEL6RD) {
1330 			err = ipip6_tunnel_update_6rd(t, &ip6rd);
1331 			if (err < 0)
1332 				goto done;
1333 		} else
1334 			ipip6_tunnel_clone_6rd(dev, sitn);
1335 
1336 		err = 0;
1337 		break;
1338 #endif
1339 
1340 	default:
1341 		err = -EINVAL;
1342 	}
1343 
1344 done:
1345 	return err;
1346 }
1347 
1348 static const struct net_device_ops ipip6_netdev_ops = {
1349 	.ndo_init	= ipip6_tunnel_init,
1350 	.ndo_uninit	= ipip6_tunnel_uninit,
1351 	.ndo_start_xmit	= sit_tunnel_xmit,
1352 	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
1353 	.ndo_get_stats64 = ip_tunnel_get_stats64,
1354 	.ndo_get_iflink = ip_tunnel_get_iflink,
1355 };
1356 
1357 static void ipip6_dev_free(struct net_device *dev)
1358 {
1359 	struct ip_tunnel *tunnel = netdev_priv(dev);
1360 
1361 	dst_cache_destroy(&tunnel->dst_cache);
1362 	free_percpu(dev->tstats);
1363 }
1364 
1365 #define SIT_FEATURES (NETIF_F_SG	   | \
1366 		      NETIF_F_FRAGLIST	   | \
1367 		      NETIF_F_HIGHDMA	   | \
1368 		      NETIF_F_GSO_SOFTWARE | \
1369 		      NETIF_F_HW_CSUM)
1370 
1371 static void ipip6_tunnel_setup(struct net_device *dev)
1372 {
1373 	struct ip_tunnel *tunnel = netdev_priv(dev);
1374 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1375 
1376 	dev->netdev_ops		= &ipip6_netdev_ops;
1377 	dev->needs_free_netdev	= true;
1378 	dev->priv_destructor	= ipip6_dev_free;
1379 
1380 	dev->type		= ARPHRD_SIT;
1381 	dev->hard_header_len	= LL_MAX_HEADER + t_hlen;
1382 	dev->mtu		= ETH_DATA_LEN - t_hlen;
1383 	dev->min_mtu		= IPV6_MIN_MTU;
1384 	dev->max_mtu		= IP6_MAX_MTU - t_hlen;
1385 	dev->flags		= IFF_NOARP;
1386 	netif_keep_dst(dev);
1387 	dev->addr_len		= 4;
1388 	dev->features		|= NETIF_F_LLTX;
1389 	dev->features		|= SIT_FEATURES;
1390 	dev->hw_features	|= SIT_FEATURES;
1391 }
1392 
1393 static int ipip6_tunnel_init(struct net_device *dev)
1394 {
1395 	struct ip_tunnel *tunnel = netdev_priv(dev);
1396 	int err;
1397 
1398 	tunnel->dev = dev;
1399 	tunnel->net = dev_net(dev);
1400 	strcpy(tunnel->parms.name, dev->name);
1401 
1402 	ipip6_tunnel_bind_dev(dev);
1403 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1404 	if (!dev->tstats)
1405 		return -ENOMEM;
1406 
1407 	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1408 	if (err) {
1409 		free_percpu(dev->tstats);
1410 		dev->tstats = NULL;
1411 		return err;
1412 	}
1413 
1414 	return 0;
1415 }
1416 
1417 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1418 {
1419 	struct ip_tunnel *tunnel = netdev_priv(dev);
1420 	struct iphdr *iph = &tunnel->parms.iph;
1421 	struct net *net = dev_net(dev);
1422 	struct sit_net *sitn = net_generic(net, sit_net_id);
1423 
1424 	iph->version		= 4;
1425 	iph->protocol		= IPPROTO_IPV6;
1426 	iph->ihl		= 5;
1427 	iph->ttl		= 64;
1428 
1429 	dev_hold(dev);
1430 	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1431 }
1432 
1433 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1434 			  struct netlink_ext_ack *extack)
1435 {
1436 	u8 proto;
1437 
1438 	if (!data || !data[IFLA_IPTUN_PROTO])
1439 		return 0;
1440 
1441 	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1442 	if (!ipip6_valid_ip_proto(proto))
1443 		return -EINVAL;
1444 
1445 	return 0;
1446 }
1447 
1448 static void ipip6_netlink_parms(struct nlattr *data[],
1449 				struct ip_tunnel_parm *parms,
1450 				__u32 *fwmark)
1451 {
1452 	memset(parms, 0, sizeof(*parms));
1453 
1454 	parms->iph.version = 4;
1455 	parms->iph.protocol = IPPROTO_IPV6;
1456 	parms->iph.ihl = 5;
1457 	parms->iph.ttl = 64;
1458 
1459 	if (!data)
1460 		return;
1461 
1462 	if (data[IFLA_IPTUN_LINK])
1463 		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1464 
1465 	if (data[IFLA_IPTUN_LOCAL])
1466 		parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1467 
1468 	if (data[IFLA_IPTUN_REMOTE])
1469 		parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1470 
1471 	if (data[IFLA_IPTUN_TTL]) {
1472 		parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1473 		if (parms->iph.ttl)
1474 			parms->iph.frag_off = htons(IP_DF);
1475 	}
1476 
1477 	if (data[IFLA_IPTUN_TOS])
1478 		parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1479 
1480 	if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1481 		parms->iph.frag_off = htons(IP_DF);
1482 
1483 	if (data[IFLA_IPTUN_FLAGS])
1484 		parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1485 
1486 	if (data[IFLA_IPTUN_PROTO])
1487 		parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1488 
1489 	if (data[IFLA_IPTUN_FWMARK])
1490 		*fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1491 }
1492 
1493 /* This function returns true when ENCAP attributes are present in the nl msg */
1494 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1495 				      struct ip_tunnel_encap *ipencap)
1496 {
1497 	bool ret = false;
1498 
1499 	memset(ipencap, 0, sizeof(*ipencap));
1500 
1501 	if (!data)
1502 		return ret;
1503 
1504 	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1505 		ret = true;
1506 		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1507 	}
1508 
1509 	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1510 		ret = true;
1511 		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1512 	}
1513 
1514 	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1515 		ret = true;
1516 		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1517 	}
1518 
1519 	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1520 		ret = true;
1521 		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1522 	}
1523 
1524 	return ret;
1525 }
1526 
1527 #ifdef CONFIG_IPV6_SIT_6RD
1528 /* This function returns true when 6RD attributes are present in the nl msg */
1529 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1530 				    struct ip_tunnel_6rd *ip6rd)
1531 {
1532 	bool ret = false;
1533 	memset(ip6rd, 0, sizeof(*ip6rd));
1534 
1535 	if (!data)
1536 		return ret;
1537 
1538 	if (data[IFLA_IPTUN_6RD_PREFIX]) {
1539 		ret = true;
1540 		ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1541 	}
1542 
1543 	if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1544 		ret = true;
1545 		ip6rd->relay_prefix =
1546 			nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1547 	}
1548 
1549 	if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1550 		ret = true;
1551 		ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1552 	}
1553 
1554 	if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1555 		ret = true;
1556 		ip6rd->relay_prefixlen =
1557 			nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1558 	}
1559 
1560 	return ret;
1561 }
1562 #endif
1563 
1564 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1565 			 struct nlattr *tb[], struct nlattr *data[],
1566 			 struct netlink_ext_ack *extack)
1567 {
1568 	struct net *net = dev_net(dev);
1569 	struct ip_tunnel *nt;
1570 	struct ip_tunnel_encap ipencap;
1571 #ifdef CONFIG_IPV6_SIT_6RD
1572 	struct ip_tunnel_6rd ip6rd;
1573 #endif
1574 	int err;
1575 
1576 	nt = netdev_priv(dev);
1577 
1578 	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1579 		err = ip_tunnel_encap_setup(nt, &ipencap);
1580 		if (err < 0)
1581 			return err;
1582 	}
1583 
1584 	ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1585 
1586 	if (ipip6_tunnel_locate(net, &nt->parms, 0))
1587 		return -EEXIST;
1588 
1589 	err = ipip6_tunnel_create(dev);
1590 	if (err < 0)
1591 		return err;
1592 
1593 	if (tb[IFLA_MTU]) {
1594 		u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1595 
1596 		if (mtu >= IPV6_MIN_MTU &&
1597 		    mtu <= IP6_MAX_MTU - dev->hard_header_len)
1598 			dev->mtu = mtu;
1599 	}
1600 
1601 #ifdef CONFIG_IPV6_SIT_6RD
1602 	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1603 		err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1604 #endif
1605 
1606 	return err;
1607 }
1608 
1609 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1610 			    struct nlattr *data[],
1611 			    struct netlink_ext_ack *extack)
1612 {
1613 	struct ip_tunnel *t = netdev_priv(dev);
1614 	struct ip_tunnel_parm p;
1615 	struct ip_tunnel_encap ipencap;
1616 	struct net *net = t->net;
1617 	struct sit_net *sitn = net_generic(net, sit_net_id);
1618 #ifdef CONFIG_IPV6_SIT_6RD
1619 	struct ip_tunnel_6rd ip6rd;
1620 #endif
1621 	__u32 fwmark = t->fwmark;
1622 	int err;
1623 
1624 	if (dev == sitn->fb_tunnel_dev)
1625 		return -EINVAL;
1626 
1627 	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1628 		err = ip_tunnel_encap_setup(t, &ipencap);
1629 		if (err < 0)
1630 			return err;
1631 	}
1632 
1633 	ipip6_netlink_parms(data, &p, &fwmark);
1634 
1635 	if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1636 	    (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1637 		return -EINVAL;
1638 
1639 	t = ipip6_tunnel_locate(net, &p, 0);
1640 
1641 	if (t) {
1642 		if (t->dev != dev)
1643 			return -EEXIST;
1644 	} else
1645 		t = netdev_priv(dev);
1646 
1647 	ipip6_tunnel_update(t, &p, fwmark);
1648 
1649 #ifdef CONFIG_IPV6_SIT_6RD
1650 	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1651 		return ipip6_tunnel_update_6rd(t, &ip6rd);
1652 #endif
1653 
1654 	return 0;
1655 }
1656 
1657 static size_t ipip6_get_size(const struct net_device *dev)
1658 {
1659 	return
1660 		/* IFLA_IPTUN_LINK */
1661 		nla_total_size(4) +
1662 		/* IFLA_IPTUN_LOCAL */
1663 		nla_total_size(4) +
1664 		/* IFLA_IPTUN_REMOTE */
1665 		nla_total_size(4) +
1666 		/* IFLA_IPTUN_TTL */
1667 		nla_total_size(1) +
1668 		/* IFLA_IPTUN_TOS */
1669 		nla_total_size(1) +
1670 		/* IFLA_IPTUN_PMTUDISC */
1671 		nla_total_size(1) +
1672 		/* IFLA_IPTUN_FLAGS */
1673 		nla_total_size(2) +
1674 		/* IFLA_IPTUN_PROTO */
1675 		nla_total_size(1) +
1676 #ifdef CONFIG_IPV6_SIT_6RD
1677 		/* IFLA_IPTUN_6RD_PREFIX */
1678 		nla_total_size(sizeof(struct in6_addr)) +
1679 		/* IFLA_IPTUN_6RD_RELAY_PREFIX */
1680 		nla_total_size(4) +
1681 		/* IFLA_IPTUN_6RD_PREFIXLEN */
1682 		nla_total_size(2) +
1683 		/* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1684 		nla_total_size(2) +
1685 #endif
1686 		/* IFLA_IPTUN_ENCAP_TYPE */
1687 		nla_total_size(2) +
1688 		/* IFLA_IPTUN_ENCAP_FLAGS */
1689 		nla_total_size(2) +
1690 		/* IFLA_IPTUN_ENCAP_SPORT */
1691 		nla_total_size(2) +
1692 		/* IFLA_IPTUN_ENCAP_DPORT */
1693 		nla_total_size(2) +
1694 		/* IFLA_IPTUN_FWMARK */
1695 		nla_total_size(4) +
1696 		0;
1697 }
1698 
1699 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1700 {
1701 	struct ip_tunnel *tunnel = netdev_priv(dev);
1702 	struct ip_tunnel_parm *parm = &tunnel->parms;
1703 
1704 	if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1705 	    nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1706 	    nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1707 	    nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1708 	    nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1709 	    nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1710 		       !!(parm->iph.frag_off & htons(IP_DF))) ||
1711 	    nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1712 	    nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags) ||
1713 	    nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1714 		goto nla_put_failure;
1715 
1716 #ifdef CONFIG_IPV6_SIT_6RD
1717 	if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1718 			     &tunnel->ip6rd.prefix) ||
1719 	    nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1720 			    tunnel->ip6rd.relay_prefix) ||
1721 	    nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1722 			tunnel->ip6rd.prefixlen) ||
1723 	    nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1724 			tunnel->ip6rd.relay_prefixlen))
1725 		goto nla_put_failure;
1726 #endif
1727 
1728 	if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1729 			tunnel->encap.type) ||
1730 	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1731 			tunnel->encap.sport) ||
1732 	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1733 			tunnel->encap.dport) ||
1734 	    nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1735 			tunnel->encap.flags))
1736 		goto nla_put_failure;
1737 
1738 	return 0;
1739 
1740 nla_put_failure:
1741 	return -EMSGSIZE;
1742 }
1743 
1744 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1745 	[IFLA_IPTUN_LINK]		= { .type = NLA_U32 },
1746 	[IFLA_IPTUN_LOCAL]		= { .type = NLA_U32 },
1747 	[IFLA_IPTUN_REMOTE]		= { .type = NLA_U32 },
1748 	[IFLA_IPTUN_TTL]		= { .type = NLA_U8 },
1749 	[IFLA_IPTUN_TOS]		= { .type = NLA_U8 },
1750 	[IFLA_IPTUN_PMTUDISC]		= { .type = NLA_U8 },
1751 	[IFLA_IPTUN_FLAGS]		= { .type = NLA_U16 },
1752 	[IFLA_IPTUN_PROTO]		= { .type = NLA_U8 },
1753 #ifdef CONFIG_IPV6_SIT_6RD
1754 	[IFLA_IPTUN_6RD_PREFIX]		= { .len = sizeof(struct in6_addr) },
1755 	[IFLA_IPTUN_6RD_RELAY_PREFIX]	= { .type = NLA_U32 },
1756 	[IFLA_IPTUN_6RD_PREFIXLEN]	= { .type = NLA_U16 },
1757 	[IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1758 #endif
1759 	[IFLA_IPTUN_ENCAP_TYPE]		= { .type = NLA_U16 },
1760 	[IFLA_IPTUN_ENCAP_FLAGS]	= { .type = NLA_U16 },
1761 	[IFLA_IPTUN_ENCAP_SPORT]	= { .type = NLA_U16 },
1762 	[IFLA_IPTUN_ENCAP_DPORT]	= { .type = NLA_U16 },
1763 	[IFLA_IPTUN_FWMARK]		= { .type = NLA_U32 },
1764 };
1765 
1766 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1767 {
1768 	struct net *net = dev_net(dev);
1769 	struct sit_net *sitn = net_generic(net, sit_net_id);
1770 
1771 	if (dev != sitn->fb_tunnel_dev)
1772 		unregister_netdevice_queue(dev, head);
1773 }
1774 
1775 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1776 	.kind		= "sit",
1777 	.maxtype	= IFLA_IPTUN_MAX,
1778 	.policy		= ipip6_policy,
1779 	.priv_size	= sizeof(struct ip_tunnel),
1780 	.setup		= ipip6_tunnel_setup,
1781 	.validate	= ipip6_validate,
1782 	.newlink	= ipip6_newlink,
1783 	.changelink	= ipip6_changelink,
1784 	.get_size	= ipip6_get_size,
1785 	.fill_info	= ipip6_fill_info,
1786 	.dellink	= ipip6_dellink,
1787 	.get_link_net	= ip_tunnel_get_link_net,
1788 };
1789 
1790 static struct xfrm_tunnel sit_handler __read_mostly = {
1791 	.handler	=	ipip6_rcv,
1792 	.err_handler	=	ipip6_err,
1793 	.priority	=	1,
1794 };
1795 
1796 static struct xfrm_tunnel ipip_handler __read_mostly = {
1797 	.handler	=	ipip_rcv,
1798 	.err_handler	=	ipip6_err,
1799 	.priority	=	2,
1800 };
1801 
1802 #if IS_ENABLED(CONFIG_MPLS)
1803 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1804 	.handler	=	mplsip_rcv,
1805 	.err_handler	=	ipip6_err,
1806 	.priority	=	2,
1807 };
1808 #endif
1809 
1810 static void __net_exit sit_destroy_tunnels(struct net *net,
1811 					   struct list_head *head)
1812 {
1813 	struct sit_net *sitn = net_generic(net, sit_net_id);
1814 	struct net_device *dev, *aux;
1815 	int prio;
1816 
1817 	for_each_netdev_safe(net, dev, aux)
1818 		if (dev->rtnl_link_ops == &sit_link_ops)
1819 			unregister_netdevice_queue(dev, head);
1820 
1821 	for (prio = 1; prio < 4; prio++) {
1822 		int h;
1823 		for (h = 0; h < IP6_SIT_HASH_SIZE; h++) {
1824 			struct ip_tunnel *t;
1825 
1826 			t = rtnl_dereference(sitn->tunnels[prio][h]);
1827 			while (t) {
1828 				/* If dev is in the same netns, it has already
1829 				 * been added to the list by the previous loop.
1830 				 */
1831 				if (!net_eq(dev_net(t->dev), net))
1832 					unregister_netdevice_queue(t->dev,
1833 								   head);
1834 				t = rtnl_dereference(t->next);
1835 			}
1836 		}
1837 	}
1838 }
1839 
1840 static int __net_init sit_init_net(struct net *net)
1841 {
1842 	struct sit_net *sitn = net_generic(net, sit_net_id);
1843 	struct ip_tunnel *t;
1844 	int err;
1845 
1846 	sitn->tunnels[0] = sitn->tunnels_wc;
1847 	sitn->tunnels[1] = sitn->tunnels_l;
1848 	sitn->tunnels[2] = sitn->tunnels_r;
1849 	sitn->tunnels[3] = sitn->tunnels_r_l;
1850 
1851 	if (!net_has_fallback_tunnels(net))
1852 		return 0;
1853 
1854 	sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1855 					   NET_NAME_UNKNOWN,
1856 					   ipip6_tunnel_setup);
1857 	if (!sitn->fb_tunnel_dev) {
1858 		err = -ENOMEM;
1859 		goto err_alloc_dev;
1860 	}
1861 	dev_net_set(sitn->fb_tunnel_dev, net);
1862 	sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1863 	/* FB netdevice is special: we have one, and only one per netns.
1864 	 * Allowing to move it to another netns is clearly unsafe.
1865 	 */
1866 	sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1867 
1868 	err = register_netdev(sitn->fb_tunnel_dev);
1869 	if (err)
1870 		goto err_reg_dev;
1871 
1872 	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1873 	ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1874 
1875 	t = netdev_priv(sitn->fb_tunnel_dev);
1876 
1877 	strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1878 	return 0;
1879 
1880 err_reg_dev:
1881 	ipip6_dev_free(sitn->fb_tunnel_dev);
1882 	free_netdev(sitn->fb_tunnel_dev);
1883 err_alloc_dev:
1884 	return err;
1885 }
1886 
1887 static void __net_exit sit_exit_batch_net(struct list_head *net_list)
1888 {
1889 	LIST_HEAD(list);
1890 	struct net *net;
1891 
1892 	rtnl_lock();
1893 	list_for_each_entry(net, net_list, exit_list)
1894 		sit_destroy_tunnels(net, &list);
1895 
1896 	unregister_netdevice_many(&list);
1897 	rtnl_unlock();
1898 }
1899 
1900 static struct pernet_operations sit_net_ops = {
1901 	.init = sit_init_net,
1902 	.exit_batch = sit_exit_batch_net,
1903 	.id   = &sit_net_id,
1904 	.size = sizeof(struct sit_net),
1905 };
1906 
1907 static void __exit sit_cleanup(void)
1908 {
1909 	rtnl_link_unregister(&sit_link_ops);
1910 	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1911 	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1912 #if IS_ENABLED(CONFIG_MPLS)
1913 	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1914 #endif
1915 
1916 	unregister_pernet_device(&sit_net_ops);
1917 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1918 }
1919 
1920 static int __init sit_init(void)
1921 {
1922 	int err;
1923 
1924 	pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1925 
1926 	err = register_pernet_device(&sit_net_ops);
1927 	if (err < 0)
1928 		return err;
1929 	err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1930 	if (err < 0) {
1931 		pr_info("%s: can't register ip6ip4\n", __func__);
1932 		goto xfrm_tunnel_failed;
1933 	}
1934 	err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1935 	if (err < 0) {
1936 		pr_info("%s: can't register ip4ip4\n", __func__);
1937 		goto xfrm_tunnel4_failed;
1938 	}
1939 #if IS_ENABLED(CONFIG_MPLS)
1940 	err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1941 	if (err < 0) {
1942 		pr_info("%s: can't register mplsip\n", __func__);
1943 		goto xfrm_tunnel_mpls_failed;
1944 	}
1945 #endif
1946 	err = rtnl_link_register(&sit_link_ops);
1947 	if (err < 0)
1948 		goto rtnl_link_failed;
1949 
1950 out:
1951 	return err;
1952 
1953 rtnl_link_failed:
1954 #if IS_ENABLED(CONFIG_MPLS)
1955 	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1956 xfrm_tunnel_mpls_failed:
1957 #endif
1958 	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1959 xfrm_tunnel4_failed:
1960 	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1961 xfrm_tunnel_failed:
1962 	unregister_pernet_device(&sit_net_ops);
1963 	goto out;
1964 }
1965 
1966 module_init(sit_init);
1967 module_exit(sit_cleanup);
1968 MODULE_LICENSE("GPL");
1969 MODULE_ALIAS_RTNL_LINK("sit");
1970 MODULE_ALIAS_NETDEV("sit0");
1971