xref: /openbmc/linux/net/ipv6/sit.c (revision 11788d9b)
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 static inline struct sit_net *dev_to_sit_net(struct net_device *dev)
87 {
88 	struct ip_tunnel *t = netdev_priv(dev);
89 
90 	return net_generic(t->net, sit_net_id);
91 }
92 
93 /*
94  * Must be invoked with rcu_read_lock
95  */
96 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
97 					     struct net_device *dev,
98 					     __be32 remote, __be32 local,
99 					     int sifindex)
100 {
101 	unsigned int h0 = HASH(remote);
102 	unsigned int h1 = HASH(local);
103 	struct ip_tunnel *t;
104 	struct sit_net *sitn = net_generic(net, sit_net_id);
105 	int ifindex = dev ? dev->ifindex : 0;
106 
107 	for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
108 		if (local == t->parms.iph.saddr &&
109 		    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_r[h0]) {
116 		if (remote == t->parms.iph.daddr &&
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 	for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
123 		if (local == t->parms.iph.saddr &&
124 		    (!dev || !t->parms.link || ifindex == t->parms.link ||
125 		     sifindex == t->parms.link) &&
126 		    (t->dev->flags & IFF_UP))
127 			return t;
128 	}
129 	t = rcu_dereference(sitn->tunnels_wc[0]);
130 	if (t && (t->dev->flags & IFF_UP))
131 		return t;
132 	return NULL;
133 }
134 
135 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
136 		struct ip_tunnel_parm *parms)
137 {
138 	__be32 remote = parms->iph.daddr;
139 	__be32 local = parms->iph.saddr;
140 	unsigned int h = 0;
141 	int prio = 0;
142 
143 	if (remote) {
144 		prio |= 2;
145 		h ^= HASH(remote);
146 	}
147 	if (local) {
148 		prio |= 1;
149 		h ^= HASH(local);
150 	}
151 	return &sitn->tunnels[prio][h];
152 }
153 
154 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
155 		struct ip_tunnel *t)
156 {
157 	return __ipip6_bucket(sitn, &t->parms);
158 }
159 
160 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
161 {
162 	struct ip_tunnel __rcu **tp;
163 	struct ip_tunnel *iter;
164 
165 	for (tp = ipip6_bucket(sitn, t);
166 	     (iter = rtnl_dereference(*tp)) != NULL;
167 	     tp = &iter->next) {
168 		if (t == iter) {
169 			rcu_assign_pointer(*tp, t->next);
170 			break;
171 		}
172 	}
173 }
174 
175 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
176 {
177 	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
178 
179 	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
180 	rcu_assign_pointer(*tp, t);
181 }
182 
183 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
184 {
185 #ifdef CONFIG_IPV6_SIT_6RD
186 	struct ip_tunnel *t = netdev_priv(dev);
187 
188 	if (dev == sitn->fb_tunnel_dev || !sitn->fb_tunnel_dev) {
189 		ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
190 		t->ip6rd.relay_prefix = 0;
191 		t->ip6rd.prefixlen = 16;
192 		t->ip6rd.relay_prefixlen = 0;
193 	} else {
194 		struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
195 		memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
196 	}
197 #endif
198 }
199 
200 static int ipip6_tunnel_create(struct net_device *dev)
201 {
202 	struct ip_tunnel *t = netdev_priv(dev);
203 	struct net *net = dev_net(dev);
204 	struct sit_net *sitn = net_generic(net, sit_net_id);
205 	int err;
206 
207 	memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
208 	memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
209 
210 	if ((__force u16)t->parms.i_flags & SIT_ISATAP)
211 		dev->priv_flags |= IFF_ISATAP;
212 
213 	dev->rtnl_link_ops = &sit_link_ops;
214 
215 	err = register_netdevice(dev);
216 	if (err < 0)
217 		goto out;
218 
219 	ipip6_tunnel_clone_6rd(dev, sitn);
220 
221 	dev_hold(dev);
222 
223 	ipip6_tunnel_link(sitn, t);
224 	return 0;
225 
226 out:
227 	return err;
228 }
229 
230 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
231 		struct ip_tunnel_parm *parms, int create)
232 {
233 	__be32 remote = parms->iph.daddr;
234 	__be32 local = parms->iph.saddr;
235 	struct ip_tunnel *t, *nt;
236 	struct ip_tunnel __rcu **tp;
237 	struct net_device *dev;
238 	char name[IFNAMSIZ];
239 	struct sit_net *sitn = net_generic(net, sit_net_id);
240 
241 	for (tp = __ipip6_bucket(sitn, parms);
242 	    (t = rtnl_dereference(*tp)) != NULL;
243 	     tp = &t->next) {
244 		if (local == t->parms.iph.saddr &&
245 		    remote == t->parms.iph.daddr &&
246 		    parms->link == t->parms.link) {
247 			if (create)
248 				return NULL;
249 			else
250 				return t;
251 		}
252 	}
253 	if (!create)
254 		goto failed;
255 
256 	if (parms->name[0]) {
257 		if (!dev_valid_name(parms->name))
258 			goto failed;
259 		strlcpy(name, parms->name, IFNAMSIZ);
260 	} else {
261 		strcpy(name, "sit%d");
262 	}
263 	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
264 			   ipip6_tunnel_setup);
265 	if (!dev)
266 		return NULL;
267 
268 	dev_net_set(dev, net);
269 
270 	nt = netdev_priv(dev);
271 
272 	nt->parms = *parms;
273 	if (ipip6_tunnel_create(dev) < 0)
274 		goto failed_free;
275 
276 	return nt;
277 
278 failed_free:
279 	free_netdev(dev);
280 failed:
281 	return NULL;
282 }
283 
284 #define for_each_prl_rcu(start)			\
285 	for (prl = rcu_dereference(start);	\
286 	     prl;				\
287 	     prl = rcu_dereference(prl->next))
288 
289 static struct ip_tunnel_prl_entry *
290 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
291 {
292 	struct ip_tunnel_prl_entry *prl;
293 
294 	for_each_prl_rcu(t->prl)
295 		if (prl->addr == addr)
296 			break;
297 	return prl;
298 
299 }
300 
301 static int ipip6_tunnel_get_prl(struct net_device *dev, struct ifreq *ifr)
302 {
303 	struct ip_tunnel_prl __user *a = ifr->ifr_ifru.ifru_data;
304 	struct ip_tunnel *t = netdev_priv(dev);
305 	struct ip_tunnel_prl kprl, *kp;
306 	struct ip_tunnel_prl_entry *prl;
307 	unsigned int cmax, c = 0, ca, len;
308 	int ret = 0;
309 
310 	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
311 		return -EINVAL;
312 
313 	if (copy_from_user(&kprl, a, sizeof(kprl)))
314 		return -EFAULT;
315 	cmax = kprl.datalen / sizeof(kprl);
316 	if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
317 		cmax = 1;
318 
319 	/* For simple GET or for root users,
320 	 * we try harder to allocate.
321 	 */
322 	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
323 		kcalloc(cmax, sizeof(*kp), GFP_KERNEL | __GFP_NOWARN) :
324 		NULL;
325 
326 	rcu_read_lock();
327 
328 	ca = t->prl_count < cmax ? t->prl_count : cmax;
329 
330 	if (!kp) {
331 		/* We don't try hard to allocate much memory for
332 		 * non-root users.
333 		 * For root users, retry allocating enough memory for
334 		 * the answer.
335 		 */
336 		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
337 		if (!kp) {
338 			ret = -ENOMEM;
339 			goto out;
340 		}
341 	}
342 
343 	c = 0;
344 	for_each_prl_rcu(t->prl) {
345 		if (c >= cmax)
346 			break;
347 		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
348 			continue;
349 		kp[c].addr = prl->addr;
350 		kp[c].flags = prl->flags;
351 		c++;
352 		if (kprl.addr != htonl(INADDR_ANY))
353 			break;
354 	}
355 out:
356 	rcu_read_unlock();
357 
358 	len = sizeof(*kp) * c;
359 	ret = 0;
360 	if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
361 		ret = -EFAULT;
362 
363 	kfree(kp);
364 
365 	return ret;
366 }
367 
368 static int
369 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
370 {
371 	struct ip_tunnel_prl_entry *p;
372 	int err = 0;
373 
374 	if (a->addr == htonl(INADDR_ANY))
375 		return -EINVAL;
376 
377 	ASSERT_RTNL();
378 
379 	for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
380 		if (p->addr == a->addr) {
381 			if (chg) {
382 				p->flags = a->flags;
383 				goto out;
384 			}
385 			err = -EEXIST;
386 			goto out;
387 		}
388 	}
389 
390 	if (chg) {
391 		err = -ENXIO;
392 		goto out;
393 	}
394 
395 	p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
396 	if (!p) {
397 		err = -ENOBUFS;
398 		goto out;
399 	}
400 
401 	p->next = t->prl;
402 	p->addr = a->addr;
403 	p->flags = a->flags;
404 	t->prl_count++;
405 	rcu_assign_pointer(t->prl, p);
406 out:
407 	return err;
408 }
409 
410 static void prl_list_destroy_rcu(struct rcu_head *head)
411 {
412 	struct ip_tunnel_prl_entry *p, *n;
413 
414 	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
415 	do {
416 		n = rcu_dereference_protected(p->next, 1);
417 		kfree(p);
418 		p = n;
419 	} while (p);
420 }
421 
422 static int
423 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
424 {
425 	struct ip_tunnel_prl_entry *x;
426 	struct ip_tunnel_prl_entry __rcu **p;
427 	int err = 0;
428 
429 	ASSERT_RTNL();
430 
431 	if (a && a->addr != htonl(INADDR_ANY)) {
432 		for (p = &t->prl;
433 		     (x = rtnl_dereference(*p)) != NULL;
434 		     p = &x->next) {
435 			if (x->addr == a->addr) {
436 				*p = x->next;
437 				kfree_rcu(x, rcu_head);
438 				t->prl_count--;
439 				goto out;
440 			}
441 		}
442 		err = -ENXIO;
443 	} else {
444 		x = rtnl_dereference(t->prl);
445 		if (x) {
446 			t->prl_count = 0;
447 			call_rcu(&x->rcu_head, prl_list_destroy_rcu);
448 			t->prl = NULL;
449 		}
450 	}
451 out:
452 	return err;
453 }
454 
455 static int ipip6_tunnel_prl_ctl(struct net_device *dev, struct ifreq *ifr,
456 		int cmd)
457 {
458 	struct ip_tunnel *t = netdev_priv(dev);
459 	struct ip_tunnel_prl prl;
460 	int err;
461 
462 	if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
463 		return -EPERM;
464 	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
465 		return -EINVAL;
466 
467 	if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
468 		return -EFAULT;
469 
470 	switch (cmd) {
471 	case SIOCDELPRL:
472 		err = ipip6_tunnel_del_prl(t, &prl);
473 		break;
474 	case SIOCADDPRL:
475 	case SIOCCHGPRL:
476 		err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
477 		break;
478 	}
479 	dst_cache_reset(&t->dst_cache);
480 	netdev_state_change(dev);
481 	return err;
482 }
483 
484 static int
485 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
486 {
487 	struct ip_tunnel_prl_entry *p;
488 	int ok = 1;
489 
490 	rcu_read_lock();
491 	p = __ipip6_tunnel_locate_prl(t, iph->saddr);
492 	if (p) {
493 		if (p->flags & PRL_DEFAULT)
494 			skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
495 		else
496 			skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
497 	} else {
498 		const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
499 
500 		if (ipv6_addr_is_isatap(addr6) &&
501 		    (addr6->s6_addr32[3] == iph->saddr) &&
502 		    ipv6_chk_prefix(addr6, t->dev))
503 			skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
504 		else
505 			ok = 0;
506 	}
507 	rcu_read_unlock();
508 	return ok;
509 }
510 
511 static void ipip6_tunnel_uninit(struct net_device *dev)
512 {
513 	struct ip_tunnel *tunnel = netdev_priv(dev);
514 	struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
515 
516 	if (dev == sitn->fb_tunnel_dev) {
517 		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
518 	} else {
519 		ipip6_tunnel_unlink(sitn, tunnel);
520 		ipip6_tunnel_del_prl(tunnel, NULL);
521 	}
522 	dst_cache_reset(&tunnel->dst_cache);
523 	dev_put(dev);
524 }
525 
526 static int ipip6_err(struct sk_buff *skb, u32 info)
527 {
528 	const struct iphdr *iph = (const struct iphdr *)skb->data;
529 	const int type = icmp_hdr(skb)->type;
530 	const int code = icmp_hdr(skb)->code;
531 	unsigned int data_len = 0;
532 	struct ip_tunnel *t;
533 	int sifindex;
534 	int err;
535 
536 	switch (type) {
537 	default:
538 	case ICMP_PARAMETERPROB:
539 		return 0;
540 
541 	case ICMP_DEST_UNREACH:
542 		switch (code) {
543 		case ICMP_SR_FAILED:
544 			/* Impossible event. */
545 			return 0;
546 		default:
547 			/* All others are translated to HOST_UNREACH.
548 			   rfc2003 contains "deep thoughts" about NET_UNREACH,
549 			   I believe they are just ether pollution. --ANK
550 			 */
551 			break;
552 		}
553 		break;
554 	case ICMP_TIME_EXCEEDED:
555 		if (code != ICMP_EXC_TTL)
556 			return 0;
557 		data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
558 		break;
559 	case ICMP_REDIRECT:
560 		break;
561 	}
562 
563 	err = -ENOENT;
564 
565 	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
566 	t = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
567 				iph->daddr, iph->saddr, sifindex);
568 	if (!t)
569 		goto out;
570 
571 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
572 		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
573 				 t->parms.link, iph->protocol);
574 		err = 0;
575 		goto out;
576 	}
577 	if (type == ICMP_REDIRECT) {
578 		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
579 			      iph->protocol);
580 		err = 0;
581 		goto out;
582 	}
583 
584 	err = 0;
585 	if (__in6_dev_get(skb->dev) &&
586 	    !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
587 		goto out;
588 
589 	if (t->parms.iph.daddr == 0)
590 		goto out;
591 
592 	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
593 		goto out;
594 
595 	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
596 		t->err_count++;
597 	else
598 		t->err_count = 1;
599 	t->err_time = jiffies;
600 out:
601 	return err;
602 }
603 
604 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
605 				  const struct in6_addr *v6addr)
606 {
607 	__be32 v4embed = 0;
608 	if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
609 		return true;
610 	return false;
611 }
612 
613 /* Checks if an address matches an address on the tunnel interface.
614  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
615  * Long story:
616  * This function is called after we considered the packet as spoofed
617  * in is_spoofed_6rd.
618  * We may have a router that is doing NAT for proto 41 packets
619  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
620  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
621  * function will return true, dropping the packet.
622  * But, we can still check if is spoofed against the IP
623  * addresses associated with the interface.
624  */
625 static bool only_dnatted(const struct ip_tunnel *tunnel,
626 	const struct in6_addr *v6dst)
627 {
628 	int prefix_len;
629 
630 #ifdef CONFIG_IPV6_SIT_6RD
631 	prefix_len = tunnel->ip6rd.prefixlen + 32
632 		- tunnel->ip6rd.relay_prefixlen;
633 #else
634 	prefix_len = 48;
635 #endif
636 	return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
637 }
638 
639 /* Returns true if a packet is spoofed */
640 static bool packet_is_spoofed(struct sk_buff *skb,
641 			      const struct iphdr *iph,
642 			      struct ip_tunnel *tunnel)
643 {
644 	const struct ipv6hdr *ipv6h;
645 
646 	if (tunnel->dev->priv_flags & IFF_ISATAP) {
647 		if (!isatap_chksrc(skb, iph, tunnel))
648 			return true;
649 
650 		return false;
651 	}
652 
653 	if (tunnel->dev->flags & IFF_POINTOPOINT)
654 		return false;
655 
656 	ipv6h = ipv6_hdr(skb);
657 
658 	if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
659 		net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
660 				     &iph->saddr, &ipv6h->saddr,
661 				     &iph->daddr, &ipv6h->daddr);
662 		return true;
663 	}
664 
665 	if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
666 		return false;
667 
668 	if (only_dnatted(tunnel, &ipv6h->daddr))
669 		return false;
670 
671 	net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
672 			     &iph->saddr, &ipv6h->saddr,
673 			     &iph->daddr, &ipv6h->daddr);
674 	return true;
675 }
676 
677 static int ipip6_rcv(struct sk_buff *skb)
678 {
679 	const struct iphdr *iph = ip_hdr(skb);
680 	struct ip_tunnel *tunnel;
681 	int sifindex;
682 	int err;
683 
684 	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
685 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
686 				     iph->saddr, iph->daddr, sifindex);
687 	if (tunnel) {
688 		struct pcpu_sw_netstats *tstats;
689 
690 		if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
691 		    tunnel->parms.iph.protocol != 0)
692 			goto out;
693 
694 		skb->mac_header = skb->network_header;
695 		skb_reset_network_header(skb);
696 		IPCB(skb)->flags = 0;
697 		skb->dev = tunnel->dev;
698 
699 		if (packet_is_spoofed(skb, iph, tunnel)) {
700 			tunnel->dev->stats.rx_errors++;
701 			goto out;
702 		}
703 
704 		if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
705 		    !net_eq(tunnel->net, dev_net(tunnel->dev))))
706 			goto out;
707 
708 		/* skb can be uncloned in iptunnel_pull_header, so
709 		 * old iph is no longer valid
710 		 */
711 		iph = (const struct iphdr *)skb_mac_header(skb);
712 		err = IP_ECN_decapsulate(iph, skb);
713 		if (unlikely(err)) {
714 			if (log_ecn_error)
715 				net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
716 						     &iph->saddr, iph->tos);
717 			if (err > 1) {
718 				++tunnel->dev->stats.rx_frame_errors;
719 				++tunnel->dev->stats.rx_errors;
720 				goto out;
721 			}
722 		}
723 
724 		tstats = this_cpu_ptr(tunnel->dev->tstats);
725 		u64_stats_update_begin(&tstats->syncp);
726 		tstats->rx_packets++;
727 		tstats->rx_bytes += skb->len;
728 		u64_stats_update_end(&tstats->syncp);
729 
730 		netif_rx(skb);
731 
732 		return 0;
733 	}
734 
735 	/* no tunnel matched,  let upstream know, ipsec may handle it */
736 	return 1;
737 out:
738 	kfree_skb(skb);
739 	return 0;
740 }
741 
742 static const struct tnl_ptk_info ipip_tpi = {
743 	/* no tunnel info required for ipip. */
744 	.proto = htons(ETH_P_IP),
745 };
746 
747 #if IS_ENABLED(CONFIG_MPLS)
748 static const struct tnl_ptk_info mplsip_tpi = {
749 	/* no tunnel info required for mplsip. */
750 	.proto = htons(ETH_P_MPLS_UC),
751 };
752 #endif
753 
754 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
755 {
756 	const struct iphdr *iph;
757 	struct ip_tunnel *tunnel;
758 	int sifindex;
759 
760 	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
761 
762 	iph = ip_hdr(skb);
763 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
764 				     iph->saddr, iph->daddr, sifindex);
765 	if (tunnel) {
766 		const struct tnl_ptk_info *tpi;
767 
768 		if (tunnel->parms.iph.protocol != ipproto &&
769 		    tunnel->parms.iph.protocol != 0)
770 			goto drop;
771 
772 		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
773 			goto drop;
774 #if IS_ENABLED(CONFIG_MPLS)
775 		if (ipproto == IPPROTO_MPLS)
776 			tpi = &mplsip_tpi;
777 		else
778 #endif
779 			tpi = &ipip_tpi;
780 		if (iptunnel_pull_header(skb, 0, tpi->proto, false))
781 			goto drop;
782 		return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
783 	}
784 
785 	return 1;
786 
787 drop:
788 	kfree_skb(skb);
789 	return 0;
790 }
791 
792 static int ipip_rcv(struct sk_buff *skb)
793 {
794 	return sit_tunnel_rcv(skb, IPPROTO_IPIP);
795 }
796 
797 #if IS_ENABLED(CONFIG_MPLS)
798 static int mplsip_rcv(struct sk_buff *skb)
799 {
800 	return sit_tunnel_rcv(skb, IPPROTO_MPLS);
801 }
802 #endif
803 
804 /*
805  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
806  * stores the embedded IPv4 address in v4dst and returns true.
807  */
808 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
809 		      __be32 *v4dst)
810 {
811 #ifdef CONFIG_IPV6_SIT_6RD
812 	if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
813 			      tunnel->ip6rd.prefixlen)) {
814 		unsigned int pbw0, pbi0;
815 		int pbi1;
816 		u32 d;
817 
818 		pbw0 = tunnel->ip6rd.prefixlen >> 5;
819 		pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
820 
821 		d = tunnel->ip6rd.relay_prefixlen < 32 ?
822 			(ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
823 		    tunnel->ip6rd.relay_prefixlen : 0;
824 
825 		pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
826 		if (pbi1 > 0)
827 			d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
828 			     (32 - pbi1);
829 
830 		*v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
831 		return true;
832 	}
833 #else
834 	if (v6dst->s6_addr16[0] == htons(0x2002)) {
835 		/* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
836 		memcpy(v4dst, &v6dst->s6_addr16[1], 4);
837 		return true;
838 	}
839 #endif
840 	return false;
841 }
842 
843 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
844 			     const struct in6_addr *v6dst)
845 {
846 	__be32 dst = 0;
847 	check_6rd(tunnel, v6dst, &dst);
848 	return dst;
849 }
850 
851 /*
852  *	This function assumes it is being called from dev_queue_xmit()
853  *	and that skb is filled properly by that function.
854  */
855 
856 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
857 				     struct net_device *dev)
858 {
859 	struct ip_tunnel *tunnel = netdev_priv(dev);
860 	const struct iphdr  *tiph = &tunnel->parms.iph;
861 	const struct ipv6hdr *iph6 = ipv6_hdr(skb);
862 	u8     tos = tunnel->parms.iph.tos;
863 	__be16 df = tiph->frag_off;
864 	struct rtable *rt;		/* Route to the other host */
865 	struct net_device *tdev;	/* Device to other host */
866 	unsigned int max_headroom;	/* The extra header space needed */
867 	__be32 dst = tiph->daddr;
868 	struct flowi4 fl4;
869 	int    mtu;
870 	const struct in6_addr *addr6;
871 	int addr_type;
872 	u8 ttl;
873 	u8 protocol = IPPROTO_IPV6;
874 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
875 
876 	if (tos == 1)
877 		tos = ipv6_get_dsfield(iph6);
878 
879 	/* ISATAP (RFC4214) - must come before 6to4 */
880 	if (dev->priv_flags & IFF_ISATAP) {
881 		struct neighbour *neigh = NULL;
882 		bool do_tx_error = false;
883 
884 		if (skb_dst(skb))
885 			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
886 
887 		if (!neigh) {
888 			net_dbg_ratelimited("nexthop == NULL\n");
889 			goto tx_error;
890 		}
891 
892 		addr6 = (const struct in6_addr *)&neigh->primary_key;
893 		addr_type = ipv6_addr_type(addr6);
894 
895 		if ((addr_type & IPV6_ADDR_UNICAST) &&
896 		     ipv6_addr_is_isatap(addr6))
897 			dst = addr6->s6_addr32[3];
898 		else
899 			do_tx_error = true;
900 
901 		neigh_release(neigh);
902 		if (do_tx_error)
903 			goto tx_error;
904 	}
905 
906 	if (!dst)
907 		dst = try_6rd(tunnel, &iph6->daddr);
908 
909 	if (!dst) {
910 		struct neighbour *neigh = NULL;
911 		bool do_tx_error = false;
912 
913 		if (skb_dst(skb))
914 			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
915 
916 		if (!neigh) {
917 			net_dbg_ratelimited("nexthop == NULL\n");
918 			goto tx_error;
919 		}
920 
921 		addr6 = (const struct in6_addr *)&neigh->primary_key;
922 		addr_type = ipv6_addr_type(addr6);
923 
924 		if (addr_type == IPV6_ADDR_ANY) {
925 			addr6 = &ipv6_hdr(skb)->daddr;
926 			addr_type = ipv6_addr_type(addr6);
927 		}
928 
929 		if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
930 			dst = addr6->s6_addr32[3];
931 		else
932 			do_tx_error = true;
933 
934 		neigh_release(neigh);
935 		if (do_tx_error)
936 			goto tx_error;
937 	}
938 
939 	flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
940 			   RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
941 			   0, dst, tiph->saddr, 0, 0,
942 			   sock_net_uid(tunnel->net, NULL));
943 
944 	rt = dst_cache_get_ip4(&tunnel->dst_cache, &fl4.saddr);
945 	if (!rt) {
946 		rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
947 		if (IS_ERR(rt)) {
948 			dev->stats.tx_carrier_errors++;
949 			goto tx_error_icmp;
950 		}
951 		dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr);
952 	}
953 
954 	if (rt->rt_type != RTN_UNICAST) {
955 		ip_rt_put(rt);
956 		dev->stats.tx_carrier_errors++;
957 		goto tx_error_icmp;
958 	}
959 	tdev = rt->dst.dev;
960 
961 	if (tdev == dev) {
962 		ip_rt_put(rt);
963 		dev->stats.collisions++;
964 		goto tx_error;
965 	}
966 
967 	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
968 		ip_rt_put(rt);
969 		goto tx_error;
970 	}
971 
972 	if (df) {
973 		mtu = dst_mtu(&rt->dst) - t_hlen;
974 
975 		if (mtu < 68) {
976 			dev->stats.collisions++;
977 			ip_rt_put(rt);
978 			goto tx_error;
979 		}
980 
981 		if (mtu < IPV6_MIN_MTU) {
982 			mtu = IPV6_MIN_MTU;
983 			df = 0;
984 		}
985 
986 		if (tunnel->parms.iph.daddr)
987 			skb_dst_update_pmtu_no_confirm(skb, mtu);
988 
989 		if (skb->len > mtu && !skb_is_gso(skb)) {
990 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
991 			ip_rt_put(rt);
992 			goto tx_error;
993 		}
994 	}
995 
996 	if (tunnel->err_count > 0) {
997 		if (time_before(jiffies,
998 				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
999 			tunnel->err_count--;
1000 			dst_link_failure(skb);
1001 		} else
1002 			tunnel->err_count = 0;
1003 	}
1004 
1005 	/*
1006 	 * Okay, now see if we can stuff it in the buffer as-is.
1007 	 */
1008 	max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
1009 
1010 	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1011 	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1012 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
1013 		if (!new_skb) {
1014 			ip_rt_put(rt);
1015 			dev->stats.tx_dropped++;
1016 			kfree_skb(skb);
1017 			return NETDEV_TX_OK;
1018 		}
1019 		if (skb->sk)
1020 			skb_set_owner_w(new_skb, skb->sk);
1021 		dev_kfree_skb(skb);
1022 		skb = new_skb;
1023 		iph6 = ipv6_hdr(skb);
1024 	}
1025 	ttl = tiph->ttl;
1026 	if (ttl == 0)
1027 		ttl = iph6->hop_limit;
1028 	tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
1029 
1030 	if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
1031 		ip_rt_put(rt);
1032 		goto tx_error;
1033 	}
1034 
1035 	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
1036 
1037 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
1038 		      df, !net_eq(tunnel->net, dev_net(dev)));
1039 	return NETDEV_TX_OK;
1040 
1041 tx_error_icmp:
1042 	dst_link_failure(skb);
1043 tx_error:
1044 	kfree_skb(skb);
1045 	dev->stats.tx_errors++;
1046 	return NETDEV_TX_OK;
1047 }
1048 
1049 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
1050 				     struct net_device *dev, u8 ipproto)
1051 {
1052 	struct ip_tunnel *tunnel = netdev_priv(dev);
1053 	const struct iphdr  *tiph = &tunnel->parms.iph;
1054 
1055 	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1056 		goto tx_error;
1057 
1058 	skb_set_inner_ipproto(skb, ipproto);
1059 
1060 	ip_tunnel_xmit(skb, dev, tiph, ipproto);
1061 	return NETDEV_TX_OK;
1062 tx_error:
1063 	kfree_skb(skb);
1064 	dev->stats.tx_errors++;
1065 	return NETDEV_TX_OK;
1066 }
1067 
1068 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1069 				   struct net_device *dev)
1070 {
1071 	if (!pskb_inet_may_pull(skb))
1072 		goto tx_err;
1073 
1074 	switch (skb->protocol) {
1075 	case htons(ETH_P_IP):
1076 		sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1077 		break;
1078 	case htons(ETH_P_IPV6):
1079 		ipip6_tunnel_xmit(skb, dev);
1080 		break;
1081 #if IS_ENABLED(CONFIG_MPLS)
1082 	case htons(ETH_P_MPLS_UC):
1083 		sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1084 		break;
1085 #endif
1086 	default:
1087 		goto tx_err;
1088 	}
1089 
1090 	return NETDEV_TX_OK;
1091 
1092 tx_err:
1093 	dev->stats.tx_errors++;
1094 	kfree_skb(skb);
1095 	return NETDEV_TX_OK;
1096 
1097 }
1098 
1099 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1100 {
1101 	struct net_device *tdev = NULL;
1102 	struct ip_tunnel *tunnel;
1103 	const struct iphdr *iph;
1104 	struct flowi4 fl4;
1105 
1106 	tunnel = netdev_priv(dev);
1107 	iph = &tunnel->parms.iph;
1108 
1109 	if (iph->daddr) {
1110 		struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1111 							  NULL,
1112 							  iph->daddr, iph->saddr,
1113 							  0, 0,
1114 							  IPPROTO_IPV6,
1115 							  RT_TOS(iph->tos),
1116 							  tunnel->parms.link);
1117 
1118 		if (!IS_ERR(rt)) {
1119 			tdev = rt->dst.dev;
1120 			ip_rt_put(rt);
1121 		}
1122 		dev->flags |= IFF_POINTOPOINT;
1123 	}
1124 
1125 	if (!tdev && tunnel->parms.link)
1126 		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1127 
1128 	if (tdev && !netif_is_l3_master(tdev)) {
1129 		int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1130 
1131 		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1132 		dev->mtu = tdev->mtu - t_hlen;
1133 		if (dev->mtu < IPV6_MIN_MTU)
1134 			dev->mtu = IPV6_MIN_MTU;
1135 	}
1136 }
1137 
1138 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
1139 				__u32 fwmark)
1140 {
1141 	struct net *net = t->net;
1142 	struct sit_net *sitn = net_generic(net, sit_net_id);
1143 
1144 	ipip6_tunnel_unlink(sitn, t);
1145 	synchronize_net();
1146 	t->parms.iph.saddr = p->iph.saddr;
1147 	t->parms.iph.daddr = p->iph.daddr;
1148 	memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1149 	memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1150 	ipip6_tunnel_link(sitn, t);
1151 	t->parms.iph.ttl = p->iph.ttl;
1152 	t->parms.iph.tos = p->iph.tos;
1153 	t->parms.iph.frag_off = p->iph.frag_off;
1154 	if (t->parms.link != p->link || t->fwmark != fwmark) {
1155 		t->parms.link = p->link;
1156 		t->fwmark = fwmark;
1157 		ipip6_tunnel_bind_dev(t->dev);
1158 	}
1159 	dst_cache_reset(&t->dst_cache);
1160 	netdev_state_change(t->dev);
1161 }
1162 
1163 #ifdef CONFIG_IPV6_SIT_6RD
1164 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1165 				   struct ip_tunnel_6rd *ip6rd)
1166 {
1167 	struct in6_addr prefix;
1168 	__be32 relay_prefix;
1169 
1170 	if (ip6rd->relay_prefixlen > 32 ||
1171 	    ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1172 		return -EINVAL;
1173 
1174 	ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1175 	if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1176 		return -EINVAL;
1177 	if (ip6rd->relay_prefixlen)
1178 		relay_prefix = ip6rd->relay_prefix &
1179 			       htonl(0xffffffffUL <<
1180 				     (32 - ip6rd->relay_prefixlen));
1181 	else
1182 		relay_prefix = 0;
1183 	if (relay_prefix != ip6rd->relay_prefix)
1184 		return -EINVAL;
1185 
1186 	t->ip6rd.prefix = prefix;
1187 	t->ip6rd.relay_prefix = relay_prefix;
1188 	t->ip6rd.prefixlen = ip6rd->prefixlen;
1189 	t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1190 	dst_cache_reset(&t->dst_cache);
1191 	netdev_state_change(t->dev);
1192 	return 0;
1193 }
1194 
1195 static int
1196 ipip6_tunnel_get6rd(struct net_device *dev, struct ifreq *ifr)
1197 {
1198 	struct ip_tunnel *t = netdev_priv(dev);
1199 	struct ip_tunnel_6rd ip6rd;
1200 	struct ip_tunnel_parm p;
1201 
1202 	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1203 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1204 			return -EFAULT;
1205 		t = ipip6_tunnel_locate(t->net, &p, 0);
1206 	}
1207 	if (!t)
1208 		t = netdev_priv(dev);
1209 
1210 	ip6rd.prefix = t->ip6rd.prefix;
1211 	ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1212 	ip6rd.prefixlen = t->ip6rd.prefixlen;
1213 	ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1214 	if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd, sizeof(ip6rd)))
1215 		return -EFAULT;
1216 	return 0;
1217 }
1218 
1219 static int
1220 ipip6_tunnel_6rdctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1221 {
1222 	struct ip_tunnel *t = netdev_priv(dev);
1223 	struct ip_tunnel_6rd ip6rd;
1224 	int err;
1225 
1226 	if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1227 		return -EPERM;
1228 	if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data, sizeof(ip6rd)))
1229 		return -EFAULT;
1230 
1231 	if (cmd != SIOCDEL6RD) {
1232 		err = ipip6_tunnel_update_6rd(t, &ip6rd);
1233 		if (err < 0)
1234 			return err;
1235 	} else
1236 		ipip6_tunnel_clone_6rd(dev, dev_to_sit_net(dev));
1237 	return 0;
1238 }
1239 
1240 #endif /* CONFIG_IPV6_SIT_6RD */
1241 
1242 static bool ipip6_valid_ip_proto(u8 ipproto)
1243 {
1244 	return ipproto == IPPROTO_IPV6 ||
1245 		ipproto == IPPROTO_IPIP ||
1246 #if IS_ENABLED(CONFIG_MPLS)
1247 		ipproto == IPPROTO_MPLS ||
1248 #endif
1249 		ipproto == 0;
1250 }
1251 
1252 static int
1253 __ipip6_tunnel_ioctl_validate(struct net *net, struct ip_tunnel_parm *p)
1254 {
1255 	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1256 		return -EPERM;
1257 
1258 	if (!ipip6_valid_ip_proto(p->iph.protocol))
1259 		return -EINVAL;
1260 	if (p->iph.version != 4 ||
1261 	    p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)))
1262 		return -EINVAL;
1263 
1264 	if (p->iph.ttl)
1265 		p->iph.frag_off |= htons(IP_DF);
1266 	return 0;
1267 }
1268 
1269 static int
1270 ipip6_tunnel_get(struct net_device *dev, struct ip_tunnel_parm *p)
1271 {
1272 	struct ip_tunnel *t = netdev_priv(dev);
1273 
1274 	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
1275 		t = ipip6_tunnel_locate(t->net, p, 0);
1276 	if (!t)
1277 		t = netdev_priv(dev);
1278 	memcpy(p, &t->parms, sizeof(*p));
1279 	return 0;
1280 }
1281 
1282 static int
1283 ipip6_tunnel_add(struct net_device *dev, struct ip_tunnel_parm *p)
1284 {
1285 	struct ip_tunnel *t = netdev_priv(dev);
1286 	int err;
1287 
1288 	err = __ipip6_tunnel_ioctl_validate(t->net, p);
1289 	if (err)
1290 		return err;
1291 
1292 	t = ipip6_tunnel_locate(t->net, p, 1);
1293 	if (!t)
1294 		return -ENOBUFS;
1295 	return 0;
1296 }
1297 
1298 static int
1299 ipip6_tunnel_change(struct net_device *dev, struct ip_tunnel_parm *p)
1300 {
1301 	struct ip_tunnel *t = netdev_priv(dev);
1302 	int err;
1303 
1304 	err = __ipip6_tunnel_ioctl_validate(t->net, p);
1305 	if (err)
1306 		return err;
1307 
1308 	t = ipip6_tunnel_locate(t->net, p, 0);
1309 	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1310 		if (!t)
1311 			return -ENOENT;
1312 	} else {
1313 		if (t) {
1314 			if (t->dev != dev)
1315 				return -EEXIST;
1316 		} else {
1317 			if (((dev->flags & IFF_POINTOPOINT) && !p->iph.daddr) ||
1318 			    (!(dev->flags & IFF_POINTOPOINT) && p->iph.daddr))
1319 				return -EINVAL;
1320 			t = netdev_priv(dev);
1321 		}
1322 
1323 		ipip6_tunnel_update(t, p, t->fwmark);
1324 	}
1325 
1326 	return 0;
1327 }
1328 
1329 static int
1330 ipip6_tunnel_del(struct net_device *dev, struct ip_tunnel_parm *p)
1331 {
1332 	struct ip_tunnel *t = netdev_priv(dev);
1333 
1334 	if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1335 		return -EPERM;
1336 
1337 	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1338 		t = ipip6_tunnel_locate(t->net, p, 0);
1339 		if (!t)
1340 			return -ENOENT;
1341 		if (t == netdev_priv(dev_to_sit_net(dev)->fb_tunnel_dev))
1342 			return -EPERM;
1343 		dev = t->dev;
1344 	}
1345 	unregister_netdevice(dev);
1346 	return 0;
1347 }
1348 
1349 static int
1350 ipip6_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
1351 {
1352 	switch (cmd) {
1353 	case SIOCGETTUNNEL:
1354 		return ipip6_tunnel_get(dev, p);
1355 	case SIOCADDTUNNEL:
1356 		return ipip6_tunnel_add(dev, p);
1357 	case SIOCCHGTUNNEL:
1358 		return ipip6_tunnel_change(dev, p);
1359 	case SIOCDELTUNNEL:
1360 		return ipip6_tunnel_del(dev, p);
1361 	default:
1362 		return -EINVAL;
1363 	}
1364 }
1365 
1366 static int
1367 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1368 {
1369 	switch (cmd) {
1370 	case SIOCGETTUNNEL:
1371 	case SIOCADDTUNNEL:
1372 	case SIOCCHGTUNNEL:
1373 	case SIOCDELTUNNEL:
1374 		return ip_tunnel_ioctl(dev, ifr, cmd);
1375 	case SIOCGETPRL:
1376 		return ipip6_tunnel_get_prl(dev, ifr);
1377 	case SIOCADDPRL:
1378 	case SIOCDELPRL:
1379 	case SIOCCHGPRL:
1380 		return ipip6_tunnel_prl_ctl(dev, ifr, cmd);
1381 #ifdef CONFIG_IPV6_SIT_6RD
1382 	case SIOCGET6RD:
1383 		return ipip6_tunnel_get6rd(dev, ifr);
1384 	case SIOCADD6RD:
1385 	case SIOCCHG6RD:
1386 	case SIOCDEL6RD:
1387 		return ipip6_tunnel_6rdctl(dev, ifr, cmd);
1388 #endif
1389 	default:
1390 		return -EINVAL;
1391 	}
1392 }
1393 
1394 static const struct net_device_ops ipip6_netdev_ops = {
1395 	.ndo_init	= ipip6_tunnel_init,
1396 	.ndo_uninit	= ipip6_tunnel_uninit,
1397 	.ndo_start_xmit	= sit_tunnel_xmit,
1398 	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
1399 	.ndo_get_stats64 = ip_tunnel_get_stats64,
1400 	.ndo_get_iflink = ip_tunnel_get_iflink,
1401 	.ndo_tunnel_ctl = ipip6_tunnel_ctl,
1402 };
1403 
1404 static void ipip6_dev_free(struct net_device *dev)
1405 {
1406 	struct ip_tunnel *tunnel = netdev_priv(dev);
1407 
1408 	dst_cache_destroy(&tunnel->dst_cache);
1409 	free_percpu(dev->tstats);
1410 }
1411 
1412 #define SIT_FEATURES (NETIF_F_SG	   | \
1413 		      NETIF_F_FRAGLIST	   | \
1414 		      NETIF_F_HIGHDMA	   | \
1415 		      NETIF_F_GSO_SOFTWARE | \
1416 		      NETIF_F_HW_CSUM)
1417 
1418 static void ipip6_tunnel_setup(struct net_device *dev)
1419 {
1420 	struct ip_tunnel *tunnel = netdev_priv(dev);
1421 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1422 
1423 	dev->netdev_ops		= &ipip6_netdev_ops;
1424 	dev->header_ops		= &ip_tunnel_header_ops;
1425 	dev->needs_free_netdev	= true;
1426 	dev->priv_destructor	= ipip6_dev_free;
1427 
1428 	dev->type		= ARPHRD_SIT;
1429 	dev->hard_header_len	= LL_MAX_HEADER + t_hlen;
1430 	dev->mtu		= ETH_DATA_LEN - t_hlen;
1431 	dev->min_mtu		= IPV6_MIN_MTU;
1432 	dev->max_mtu		= IP6_MAX_MTU - t_hlen;
1433 	dev->flags		= IFF_NOARP;
1434 	netif_keep_dst(dev);
1435 	dev->addr_len		= 4;
1436 	dev->features		|= NETIF_F_LLTX;
1437 	dev->features		|= SIT_FEATURES;
1438 	dev->hw_features	|= SIT_FEATURES;
1439 }
1440 
1441 static int ipip6_tunnel_init(struct net_device *dev)
1442 {
1443 	struct ip_tunnel *tunnel = netdev_priv(dev);
1444 	int err;
1445 
1446 	tunnel->dev = dev;
1447 	tunnel->net = dev_net(dev);
1448 	strcpy(tunnel->parms.name, dev->name);
1449 
1450 	ipip6_tunnel_bind_dev(dev);
1451 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1452 	if (!dev->tstats)
1453 		return -ENOMEM;
1454 
1455 	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1456 	if (err) {
1457 		free_percpu(dev->tstats);
1458 		dev->tstats = NULL;
1459 		return err;
1460 	}
1461 
1462 	return 0;
1463 }
1464 
1465 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1466 {
1467 	struct ip_tunnel *tunnel = netdev_priv(dev);
1468 	struct iphdr *iph = &tunnel->parms.iph;
1469 	struct net *net = dev_net(dev);
1470 	struct sit_net *sitn = net_generic(net, sit_net_id);
1471 
1472 	iph->version		= 4;
1473 	iph->protocol		= IPPROTO_IPV6;
1474 	iph->ihl		= 5;
1475 	iph->ttl		= 64;
1476 
1477 	dev_hold(dev);
1478 	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1479 }
1480 
1481 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1482 			  struct netlink_ext_ack *extack)
1483 {
1484 	u8 proto;
1485 
1486 	if (!data || !data[IFLA_IPTUN_PROTO])
1487 		return 0;
1488 
1489 	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1490 	if (!ipip6_valid_ip_proto(proto))
1491 		return -EINVAL;
1492 
1493 	return 0;
1494 }
1495 
1496 static void ipip6_netlink_parms(struct nlattr *data[],
1497 				struct ip_tunnel_parm *parms,
1498 				__u32 *fwmark)
1499 {
1500 	memset(parms, 0, sizeof(*parms));
1501 
1502 	parms->iph.version = 4;
1503 	parms->iph.protocol = IPPROTO_IPV6;
1504 	parms->iph.ihl = 5;
1505 	parms->iph.ttl = 64;
1506 
1507 	if (!data)
1508 		return;
1509 
1510 	if (data[IFLA_IPTUN_LINK])
1511 		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1512 
1513 	if (data[IFLA_IPTUN_LOCAL])
1514 		parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1515 
1516 	if (data[IFLA_IPTUN_REMOTE])
1517 		parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1518 
1519 	if (data[IFLA_IPTUN_TTL]) {
1520 		parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1521 		if (parms->iph.ttl)
1522 			parms->iph.frag_off = htons(IP_DF);
1523 	}
1524 
1525 	if (data[IFLA_IPTUN_TOS])
1526 		parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1527 
1528 	if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1529 		parms->iph.frag_off = htons(IP_DF);
1530 
1531 	if (data[IFLA_IPTUN_FLAGS])
1532 		parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1533 
1534 	if (data[IFLA_IPTUN_PROTO])
1535 		parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1536 
1537 	if (data[IFLA_IPTUN_FWMARK])
1538 		*fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1539 }
1540 
1541 /* This function returns true when ENCAP attributes are present in the nl msg */
1542 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1543 				      struct ip_tunnel_encap *ipencap)
1544 {
1545 	bool ret = false;
1546 
1547 	memset(ipencap, 0, sizeof(*ipencap));
1548 
1549 	if (!data)
1550 		return ret;
1551 
1552 	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1553 		ret = true;
1554 		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1555 	}
1556 
1557 	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1558 		ret = true;
1559 		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1560 	}
1561 
1562 	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1563 		ret = true;
1564 		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1565 	}
1566 
1567 	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1568 		ret = true;
1569 		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1570 	}
1571 
1572 	return ret;
1573 }
1574 
1575 #ifdef CONFIG_IPV6_SIT_6RD
1576 /* This function returns true when 6RD attributes are present in the nl msg */
1577 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1578 				    struct ip_tunnel_6rd *ip6rd)
1579 {
1580 	bool ret = false;
1581 	memset(ip6rd, 0, sizeof(*ip6rd));
1582 
1583 	if (!data)
1584 		return ret;
1585 
1586 	if (data[IFLA_IPTUN_6RD_PREFIX]) {
1587 		ret = true;
1588 		ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1589 	}
1590 
1591 	if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1592 		ret = true;
1593 		ip6rd->relay_prefix =
1594 			nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1595 	}
1596 
1597 	if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1598 		ret = true;
1599 		ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1600 	}
1601 
1602 	if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1603 		ret = true;
1604 		ip6rd->relay_prefixlen =
1605 			nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1606 	}
1607 
1608 	return ret;
1609 }
1610 #endif
1611 
1612 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1613 			 struct nlattr *tb[], struct nlattr *data[],
1614 			 struct netlink_ext_ack *extack)
1615 {
1616 	struct net *net = dev_net(dev);
1617 	struct ip_tunnel *nt;
1618 	struct ip_tunnel_encap ipencap;
1619 #ifdef CONFIG_IPV6_SIT_6RD
1620 	struct ip_tunnel_6rd ip6rd;
1621 #endif
1622 	int err;
1623 
1624 	nt = netdev_priv(dev);
1625 
1626 	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1627 		err = ip_tunnel_encap_setup(nt, &ipencap);
1628 		if (err < 0)
1629 			return err;
1630 	}
1631 
1632 	ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1633 
1634 	if (ipip6_tunnel_locate(net, &nt->parms, 0))
1635 		return -EEXIST;
1636 
1637 	err = ipip6_tunnel_create(dev);
1638 	if (err < 0)
1639 		return err;
1640 
1641 	if (tb[IFLA_MTU]) {
1642 		u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1643 
1644 		if (mtu >= IPV6_MIN_MTU &&
1645 		    mtu <= IP6_MAX_MTU - dev->hard_header_len)
1646 			dev->mtu = mtu;
1647 	}
1648 
1649 #ifdef CONFIG_IPV6_SIT_6RD
1650 	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1651 		err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1652 #endif
1653 
1654 	return err;
1655 }
1656 
1657 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1658 			    struct nlattr *data[],
1659 			    struct netlink_ext_ack *extack)
1660 {
1661 	struct ip_tunnel *t = netdev_priv(dev);
1662 	struct ip_tunnel_parm p;
1663 	struct ip_tunnel_encap ipencap;
1664 	struct net *net = t->net;
1665 	struct sit_net *sitn = net_generic(net, sit_net_id);
1666 #ifdef CONFIG_IPV6_SIT_6RD
1667 	struct ip_tunnel_6rd ip6rd;
1668 #endif
1669 	__u32 fwmark = t->fwmark;
1670 	int err;
1671 
1672 	if (dev == sitn->fb_tunnel_dev)
1673 		return -EINVAL;
1674 
1675 	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1676 		err = ip_tunnel_encap_setup(t, &ipencap);
1677 		if (err < 0)
1678 			return err;
1679 	}
1680 
1681 	ipip6_netlink_parms(data, &p, &fwmark);
1682 
1683 	if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1684 	    (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1685 		return -EINVAL;
1686 
1687 	t = ipip6_tunnel_locate(net, &p, 0);
1688 
1689 	if (t) {
1690 		if (t->dev != dev)
1691 			return -EEXIST;
1692 	} else
1693 		t = netdev_priv(dev);
1694 
1695 	ipip6_tunnel_update(t, &p, fwmark);
1696 
1697 #ifdef CONFIG_IPV6_SIT_6RD
1698 	if (ipip6_netlink_6rd_parms(data, &ip6rd))
1699 		return ipip6_tunnel_update_6rd(t, &ip6rd);
1700 #endif
1701 
1702 	return 0;
1703 }
1704 
1705 static size_t ipip6_get_size(const struct net_device *dev)
1706 {
1707 	return
1708 		/* IFLA_IPTUN_LINK */
1709 		nla_total_size(4) +
1710 		/* IFLA_IPTUN_LOCAL */
1711 		nla_total_size(4) +
1712 		/* IFLA_IPTUN_REMOTE */
1713 		nla_total_size(4) +
1714 		/* IFLA_IPTUN_TTL */
1715 		nla_total_size(1) +
1716 		/* IFLA_IPTUN_TOS */
1717 		nla_total_size(1) +
1718 		/* IFLA_IPTUN_PMTUDISC */
1719 		nla_total_size(1) +
1720 		/* IFLA_IPTUN_FLAGS */
1721 		nla_total_size(2) +
1722 		/* IFLA_IPTUN_PROTO */
1723 		nla_total_size(1) +
1724 #ifdef CONFIG_IPV6_SIT_6RD
1725 		/* IFLA_IPTUN_6RD_PREFIX */
1726 		nla_total_size(sizeof(struct in6_addr)) +
1727 		/* IFLA_IPTUN_6RD_RELAY_PREFIX */
1728 		nla_total_size(4) +
1729 		/* IFLA_IPTUN_6RD_PREFIXLEN */
1730 		nla_total_size(2) +
1731 		/* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1732 		nla_total_size(2) +
1733 #endif
1734 		/* IFLA_IPTUN_ENCAP_TYPE */
1735 		nla_total_size(2) +
1736 		/* IFLA_IPTUN_ENCAP_FLAGS */
1737 		nla_total_size(2) +
1738 		/* IFLA_IPTUN_ENCAP_SPORT */
1739 		nla_total_size(2) +
1740 		/* IFLA_IPTUN_ENCAP_DPORT */
1741 		nla_total_size(2) +
1742 		/* IFLA_IPTUN_FWMARK */
1743 		nla_total_size(4) +
1744 		0;
1745 }
1746 
1747 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1748 {
1749 	struct ip_tunnel *tunnel = netdev_priv(dev);
1750 	struct ip_tunnel_parm *parm = &tunnel->parms;
1751 
1752 	if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1753 	    nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1754 	    nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1755 	    nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1756 	    nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1757 	    nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1758 		       !!(parm->iph.frag_off & htons(IP_DF))) ||
1759 	    nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1760 	    nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags) ||
1761 	    nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1762 		goto nla_put_failure;
1763 
1764 #ifdef CONFIG_IPV6_SIT_6RD
1765 	if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1766 			     &tunnel->ip6rd.prefix) ||
1767 	    nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1768 			    tunnel->ip6rd.relay_prefix) ||
1769 	    nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1770 			tunnel->ip6rd.prefixlen) ||
1771 	    nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1772 			tunnel->ip6rd.relay_prefixlen))
1773 		goto nla_put_failure;
1774 #endif
1775 
1776 	if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1777 			tunnel->encap.type) ||
1778 	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1779 			tunnel->encap.sport) ||
1780 	    nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1781 			tunnel->encap.dport) ||
1782 	    nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1783 			tunnel->encap.flags))
1784 		goto nla_put_failure;
1785 
1786 	return 0;
1787 
1788 nla_put_failure:
1789 	return -EMSGSIZE;
1790 }
1791 
1792 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1793 	[IFLA_IPTUN_LINK]		= { .type = NLA_U32 },
1794 	[IFLA_IPTUN_LOCAL]		= { .type = NLA_U32 },
1795 	[IFLA_IPTUN_REMOTE]		= { .type = NLA_U32 },
1796 	[IFLA_IPTUN_TTL]		= { .type = NLA_U8 },
1797 	[IFLA_IPTUN_TOS]		= { .type = NLA_U8 },
1798 	[IFLA_IPTUN_PMTUDISC]		= { .type = NLA_U8 },
1799 	[IFLA_IPTUN_FLAGS]		= { .type = NLA_U16 },
1800 	[IFLA_IPTUN_PROTO]		= { .type = NLA_U8 },
1801 #ifdef CONFIG_IPV6_SIT_6RD
1802 	[IFLA_IPTUN_6RD_PREFIX]		= { .len = sizeof(struct in6_addr) },
1803 	[IFLA_IPTUN_6RD_RELAY_PREFIX]	= { .type = NLA_U32 },
1804 	[IFLA_IPTUN_6RD_PREFIXLEN]	= { .type = NLA_U16 },
1805 	[IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1806 #endif
1807 	[IFLA_IPTUN_ENCAP_TYPE]		= { .type = NLA_U16 },
1808 	[IFLA_IPTUN_ENCAP_FLAGS]	= { .type = NLA_U16 },
1809 	[IFLA_IPTUN_ENCAP_SPORT]	= { .type = NLA_U16 },
1810 	[IFLA_IPTUN_ENCAP_DPORT]	= { .type = NLA_U16 },
1811 	[IFLA_IPTUN_FWMARK]		= { .type = NLA_U32 },
1812 };
1813 
1814 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1815 {
1816 	struct net *net = dev_net(dev);
1817 	struct sit_net *sitn = net_generic(net, sit_net_id);
1818 
1819 	if (dev != sitn->fb_tunnel_dev)
1820 		unregister_netdevice_queue(dev, head);
1821 }
1822 
1823 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1824 	.kind		= "sit",
1825 	.maxtype	= IFLA_IPTUN_MAX,
1826 	.policy		= ipip6_policy,
1827 	.priv_size	= sizeof(struct ip_tunnel),
1828 	.setup		= ipip6_tunnel_setup,
1829 	.validate	= ipip6_validate,
1830 	.newlink	= ipip6_newlink,
1831 	.changelink	= ipip6_changelink,
1832 	.get_size	= ipip6_get_size,
1833 	.fill_info	= ipip6_fill_info,
1834 	.dellink	= ipip6_dellink,
1835 	.get_link_net	= ip_tunnel_get_link_net,
1836 };
1837 
1838 static struct xfrm_tunnel sit_handler __read_mostly = {
1839 	.handler	=	ipip6_rcv,
1840 	.err_handler	=	ipip6_err,
1841 	.priority	=	1,
1842 };
1843 
1844 static struct xfrm_tunnel ipip_handler __read_mostly = {
1845 	.handler	=	ipip_rcv,
1846 	.err_handler	=	ipip6_err,
1847 	.priority	=	2,
1848 };
1849 
1850 #if IS_ENABLED(CONFIG_MPLS)
1851 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1852 	.handler	=	mplsip_rcv,
1853 	.err_handler	=	ipip6_err,
1854 	.priority	=	2,
1855 };
1856 #endif
1857 
1858 static void __net_exit sit_destroy_tunnels(struct net *net,
1859 					   struct list_head *head)
1860 {
1861 	struct sit_net *sitn = net_generic(net, sit_net_id);
1862 	struct net_device *dev, *aux;
1863 	int prio;
1864 
1865 	for_each_netdev_safe(net, dev, aux)
1866 		if (dev->rtnl_link_ops == &sit_link_ops)
1867 			unregister_netdevice_queue(dev, head);
1868 
1869 	for (prio = 1; prio < 4; prio++) {
1870 		int h;
1871 		for (h = 0; h < IP6_SIT_HASH_SIZE; h++) {
1872 			struct ip_tunnel *t;
1873 
1874 			t = rtnl_dereference(sitn->tunnels[prio][h]);
1875 			while (t) {
1876 				/* If dev is in the same netns, it has already
1877 				 * been added to the list by the previous loop.
1878 				 */
1879 				if (!net_eq(dev_net(t->dev), net))
1880 					unregister_netdevice_queue(t->dev,
1881 								   head);
1882 				t = rtnl_dereference(t->next);
1883 			}
1884 		}
1885 	}
1886 }
1887 
1888 static int __net_init sit_init_net(struct net *net)
1889 {
1890 	struct sit_net *sitn = net_generic(net, sit_net_id);
1891 	struct ip_tunnel *t;
1892 	int err;
1893 
1894 	sitn->tunnels[0] = sitn->tunnels_wc;
1895 	sitn->tunnels[1] = sitn->tunnels_l;
1896 	sitn->tunnels[2] = sitn->tunnels_r;
1897 	sitn->tunnels[3] = sitn->tunnels_r_l;
1898 
1899 	if (!net_has_fallback_tunnels(net))
1900 		return 0;
1901 
1902 	sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1903 					   NET_NAME_UNKNOWN,
1904 					   ipip6_tunnel_setup);
1905 	if (!sitn->fb_tunnel_dev) {
1906 		err = -ENOMEM;
1907 		goto err_alloc_dev;
1908 	}
1909 	dev_net_set(sitn->fb_tunnel_dev, net);
1910 	sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1911 	/* FB netdevice is special: we have one, and only one per netns.
1912 	 * Allowing to move it to another netns is clearly unsafe.
1913 	 */
1914 	sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1915 
1916 	err = register_netdev(sitn->fb_tunnel_dev);
1917 	if (err)
1918 		goto err_reg_dev;
1919 
1920 	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1921 	ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1922 
1923 	t = netdev_priv(sitn->fb_tunnel_dev);
1924 
1925 	strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1926 	return 0;
1927 
1928 err_reg_dev:
1929 	ipip6_dev_free(sitn->fb_tunnel_dev);
1930 	free_netdev(sitn->fb_tunnel_dev);
1931 err_alloc_dev:
1932 	return err;
1933 }
1934 
1935 static void __net_exit sit_exit_batch_net(struct list_head *net_list)
1936 {
1937 	LIST_HEAD(list);
1938 	struct net *net;
1939 
1940 	rtnl_lock();
1941 	list_for_each_entry(net, net_list, exit_list)
1942 		sit_destroy_tunnels(net, &list);
1943 
1944 	unregister_netdevice_many(&list);
1945 	rtnl_unlock();
1946 }
1947 
1948 static struct pernet_operations sit_net_ops = {
1949 	.init = sit_init_net,
1950 	.exit_batch = sit_exit_batch_net,
1951 	.id   = &sit_net_id,
1952 	.size = sizeof(struct sit_net),
1953 };
1954 
1955 static void __exit sit_cleanup(void)
1956 {
1957 	rtnl_link_unregister(&sit_link_ops);
1958 	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1959 	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1960 #if IS_ENABLED(CONFIG_MPLS)
1961 	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1962 #endif
1963 
1964 	unregister_pernet_device(&sit_net_ops);
1965 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1966 }
1967 
1968 static int __init sit_init(void)
1969 {
1970 	int err;
1971 
1972 	pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1973 
1974 	err = register_pernet_device(&sit_net_ops);
1975 	if (err < 0)
1976 		return err;
1977 	err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1978 	if (err < 0) {
1979 		pr_info("%s: can't register ip6ip4\n", __func__);
1980 		goto xfrm_tunnel_failed;
1981 	}
1982 	err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1983 	if (err < 0) {
1984 		pr_info("%s: can't register ip4ip4\n", __func__);
1985 		goto xfrm_tunnel4_failed;
1986 	}
1987 #if IS_ENABLED(CONFIG_MPLS)
1988 	err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1989 	if (err < 0) {
1990 		pr_info("%s: can't register mplsip\n", __func__);
1991 		goto xfrm_tunnel_mpls_failed;
1992 	}
1993 #endif
1994 	err = rtnl_link_register(&sit_link_ops);
1995 	if (err < 0)
1996 		goto rtnl_link_failed;
1997 
1998 out:
1999 	return err;
2000 
2001 rtnl_link_failed:
2002 #if IS_ENABLED(CONFIG_MPLS)
2003 	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
2004 xfrm_tunnel_mpls_failed:
2005 #endif
2006 	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
2007 xfrm_tunnel4_failed:
2008 	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
2009 xfrm_tunnel_failed:
2010 	unregister_pernet_device(&sit_net_ops);
2011 	goto out;
2012 }
2013 
2014 module_init(sit_init);
2015 module_exit(sit_cleanup);
2016 MODULE_LICENSE("GPL");
2017 MODULE_ALIAS_RTNL_LINK("sit");
2018 MODULE_ALIAS_NETDEV("sit0");
2019