xref: /kernel/linux/linux-5.10/net/ipv6/sit.c (revision 8c2ecf20)
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
64static bool log_ecn_error = true;
65module_param(log_ecn_error, bool, 0644);
66MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
67
68static int ipip6_tunnel_init(struct net_device *dev);
69static void ipip6_tunnel_setup(struct net_device *dev);
70static void ipip6_dev_free(struct net_device *dev);
71static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
72		      __be32 *v4dst);
73static struct rtnl_link_ops sit_link_ops __read_mostly;
74
75static unsigned int sit_net_id __read_mostly;
76struct 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
86static 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 */
96static 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
135static 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
154static 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
160static 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
175static 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
183static 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
200static 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	ipip6_tunnel_link(sitn, t);
222	return 0;
223
224out:
225	return err;
226}
227
228static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
229		struct ip_tunnel_parm *parms, int create)
230{
231	__be32 remote = parms->iph.daddr;
232	__be32 local = parms->iph.saddr;
233	struct ip_tunnel *t, *nt;
234	struct ip_tunnel __rcu **tp;
235	struct net_device *dev;
236	char name[IFNAMSIZ];
237	struct sit_net *sitn = net_generic(net, sit_net_id);
238
239	for (tp = __ipip6_bucket(sitn, parms);
240	    (t = rtnl_dereference(*tp)) != NULL;
241	     tp = &t->next) {
242		if (local == t->parms.iph.saddr &&
243		    remote == t->parms.iph.daddr &&
244		    parms->link == t->parms.link) {
245			if (create)
246				return NULL;
247			else
248				return t;
249		}
250	}
251	if (!create)
252		goto failed;
253
254	if (parms->name[0]) {
255		if (!dev_valid_name(parms->name))
256			goto failed;
257		strlcpy(name, parms->name, IFNAMSIZ);
258	} else {
259		strcpy(name, "sit%d");
260	}
261	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
262			   ipip6_tunnel_setup);
263	if (!dev)
264		return NULL;
265
266	dev_net_set(dev, net);
267
268	nt = netdev_priv(dev);
269
270	nt->parms = *parms;
271	if (ipip6_tunnel_create(dev) < 0)
272		goto failed_free;
273
274	return nt;
275
276failed_free:
277	free_netdev(dev);
278failed:
279	return NULL;
280}
281
282#define for_each_prl_rcu(start)			\
283	for (prl = rcu_dereference(start);	\
284	     prl;				\
285	     prl = rcu_dereference(prl->next))
286
287static struct ip_tunnel_prl_entry *
288__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
289{
290	struct ip_tunnel_prl_entry *prl;
291
292	for_each_prl_rcu(t->prl)
293		if (prl->addr == addr)
294			break;
295	return prl;
296
297}
298
299static int ipip6_tunnel_get_prl(struct net_device *dev, struct ifreq *ifr)
300{
301	struct ip_tunnel_prl __user *a = ifr->ifr_ifru.ifru_data;
302	struct ip_tunnel *t = netdev_priv(dev);
303	struct ip_tunnel_prl kprl, *kp;
304	struct ip_tunnel_prl_entry *prl;
305	unsigned int cmax, c = 0, ca, len;
306	int ret = 0;
307
308	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
309		return -EINVAL;
310
311	if (copy_from_user(&kprl, a, sizeof(kprl)))
312		return -EFAULT;
313	cmax = kprl.datalen / sizeof(kprl);
314	if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
315		cmax = 1;
316
317	/* For simple GET or for root users,
318	 * we try harder to allocate.
319	 */
320	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
321		kcalloc(cmax, sizeof(*kp), GFP_KERNEL | __GFP_NOWARN) :
322		NULL;
323
324	ca = min(t->prl_count, cmax);
325
326	if (!kp) {
327		/* We don't try hard to allocate much memory for
328		 * non-root users.
329		 * For root users, retry allocating enough memory for
330		 * the answer.
331		 */
332		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
333		if (!kp) {
334			ret = -ENOMEM;
335			goto out;
336		}
337	}
338
339	rcu_read_lock();
340	for_each_prl_rcu(t->prl) {
341		if (c >= cmax)
342			break;
343		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
344			continue;
345		kp[c].addr = prl->addr;
346		kp[c].flags = prl->flags;
347		c++;
348		if (kprl.addr != htonl(INADDR_ANY))
349			break;
350	}
351
352	rcu_read_unlock();
353
354	len = sizeof(*kp) * c;
355	ret = 0;
356	if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
357		ret = -EFAULT;
358
359	kfree(kp);
360out:
361	return ret;
362}
363
364static int
365ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
366{
367	struct ip_tunnel_prl_entry *p;
368	int err = 0;
369
370	if (a->addr == htonl(INADDR_ANY))
371		return -EINVAL;
372
373	ASSERT_RTNL();
374
375	for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
376		if (p->addr == a->addr) {
377			if (chg) {
378				p->flags = a->flags;
379				goto out;
380			}
381			err = -EEXIST;
382			goto out;
383		}
384	}
385
386	if (chg) {
387		err = -ENXIO;
388		goto out;
389	}
390
391	p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
392	if (!p) {
393		err = -ENOBUFS;
394		goto out;
395	}
396
397	p->next = t->prl;
398	p->addr = a->addr;
399	p->flags = a->flags;
400	t->prl_count++;
401	rcu_assign_pointer(t->prl, p);
402out:
403	return err;
404}
405
406static void prl_list_destroy_rcu(struct rcu_head *head)
407{
408	struct ip_tunnel_prl_entry *p, *n;
409
410	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
411	do {
412		n = rcu_dereference_protected(p->next, 1);
413		kfree(p);
414		p = n;
415	} while (p);
416}
417
418static int
419ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
420{
421	struct ip_tunnel_prl_entry *x;
422	struct ip_tunnel_prl_entry __rcu **p;
423	int err = 0;
424
425	ASSERT_RTNL();
426
427	if (a && a->addr != htonl(INADDR_ANY)) {
428		for (p = &t->prl;
429		     (x = rtnl_dereference(*p)) != NULL;
430		     p = &x->next) {
431			if (x->addr == a->addr) {
432				*p = x->next;
433				kfree_rcu(x, rcu_head);
434				t->prl_count--;
435				goto out;
436			}
437		}
438		err = -ENXIO;
439	} else {
440		x = rtnl_dereference(t->prl);
441		if (x) {
442			t->prl_count = 0;
443			call_rcu(&x->rcu_head, prl_list_destroy_rcu);
444			t->prl = NULL;
445		}
446	}
447out:
448	return err;
449}
450
451static int ipip6_tunnel_prl_ctl(struct net_device *dev, struct ifreq *ifr,
452		int cmd)
453{
454	struct ip_tunnel *t = netdev_priv(dev);
455	struct ip_tunnel_prl prl;
456	int err;
457
458	if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
459		return -EPERM;
460	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
461		return -EINVAL;
462
463	if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
464		return -EFAULT;
465
466	switch (cmd) {
467	case SIOCDELPRL:
468		err = ipip6_tunnel_del_prl(t, &prl);
469		break;
470	case SIOCADDPRL:
471	case SIOCCHGPRL:
472		err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
473		break;
474	}
475	dst_cache_reset(&t->dst_cache);
476	netdev_state_change(dev);
477	return err;
478}
479
480static int
481isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
482{
483	struct ip_tunnel_prl_entry *p;
484	int ok = 1;
485
486	rcu_read_lock();
487	p = __ipip6_tunnel_locate_prl(t, iph->saddr);
488	if (p) {
489		if (p->flags & PRL_DEFAULT)
490			skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
491		else
492			skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
493	} else {
494		const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
495
496		if (ipv6_addr_is_isatap(addr6) &&
497		    (addr6->s6_addr32[3] == iph->saddr) &&
498		    ipv6_chk_prefix(addr6, t->dev))
499			skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
500		else
501			ok = 0;
502	}
503	rcu_read_unlock();
504	return ok;
505}
506
507static void ipip6_tunnel_uninit(struct net_device *dev)
508{
509	struct ip_tunnel *tunnel = netdev_priv(dev);
510	struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
511
512	if (dev == sitn->fb_tunnel_dev) {
513		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
514	} else {
515		ipip6_tunnel_unlink(sitn, tunnel);
516		ipip6_tunnel_del_prl(tunnel, NULL);
517	}
518	dst_cache_reset(&tunnel->dst_cache);
519	dev_put(dev);
520}
521
522static int ipip6_err(struct sk_buff *skb, u32 info)
523{
524	const struct iphdr *iph = (const struct iphdr *)skb->data;
525	const int type = icmp_hdr(skb)->type;
526	const int code = icmp_hdr(skb)->code;
527	unsigned int data_len = 0;
528	struct ip_tunnel *t;
529	int sifindex;
530	int err;
531
532	switch (type) {
533	default:
534	case ICMP_PARAMETERPROB:
535		return 0;
536
537	case ICMP_DEST_UNREACH:
538		switch (code) {
539		case ICMP_SR_FAILED:
540			/* Impossible event. */
541			return 0;
542		default:
543			/* All others are translated to HOST_UNREACH.
544			   rfc2003 contains "deep thoughts" about NET_UNREACH,
545			   I believe they are just ether pollution. --ANK
546			 */
547			break;
548		}
549		break;
550	case ICMP_TIME_EXCEEDED:
551		if (code != ICMP_EXC_TTL)
552			return 0;
553		data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
554		break;
555	case ICMP_REDIRECT:
556		break;
557	}
558
559	err = -ENOENT;
560
561	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
562	t = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
563				iph->daddr, iph->saddr, sifindex);
564	if (!t)
565		goto out;
566
567	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
568		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
569				 t->parms.link, iph->protocol);
570		err = 0;
571		goto out;
572	}
573	if (type == ICMP_REDIRECT) {
574		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
575			      iph->protocol);
576		err = 0;
577		goto out;
578	}
579
580	err = 0;
581	if (__in6_dev_get(skb->dev) &&
582	    !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
583		goto out;
584
585	if (t->parms.iph.daddr == 0)
586		goto out;
587
588	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
589		goto out;
590
591	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
592		t->err_count++;
593	else
594		t->err_count = 1;
595	t->err_time = jiffies;
596out:
597	return err;
598}
599
600static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
601				  const struct in6_addr *v6addr)
602{
603	__be32 v4embed = 0;
604	if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
605		return true;
606	return false;
607}
608
609/* Checks if an address matches an address on the tunnel interface.
610 * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
611 * Long story:
612 * This function is called after we considered the packet as spoofed
613 * in is_spoofed_6rd.
614 * We may have a router that is doing NAT for proto 41 packets
615 * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
616 * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
617 * function will return true, dropping the packet.
618 * But, we can still check if is spoofed against the IP
619 * addresses associated with the interface.
620 */
621static bool only_dnatted(const struct ip_tunnel *tunnel,
622	const struct in6_addr *v6dst)
623{
624	int prefix_len;
625
626#ifdef CONFIG_IPV6_SIT_6RD
627	prefix_len = tunnel->ip6rd.prefixlen + 32
628		- tunnel->ip6rd.relay_prefixlen;
629#else
630	prefix_len = 48;
631#endif
632	return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
633}
634
635/* Returns true if a packet is spoofed */
636static bool packet_is_spoofed(struct sk_buff *skb,
637			      const struct iphdr *iph,
638			      struct ip_tunnel *tunnel)
639{
640	const struct ipv6hdr *ipv6h;
641
642	if (tunnel->dev->priv_flags & IFF_ISATAP) {
643		if (!isatap_chksrc(skb, iph, tunnel))
644			return true;
645
646		return false;
647	}
648
649	if (tunnel->dev->flags & IFF_POINTOPOINT)
650		return false;
651
652	ipv6h = ipv6_hdr(skb);
653
654	if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
655		net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
656				     &iph->saddr, &ipv6h->saddr,
657				     &iph->daddr, &ipv6h->daddr);
658		return true;
659	}
660
661	if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
662		return false;
663
664	if (only_dnatted(tunnel, &ipv6h->daddr))
665		return false;
666
667	net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
668			     &iph->saddr, &ipv6h->saddr,
669			     &iph->daddr, &ipv6h->daddr);
670	return true;
671}
672
673static int ipip6_rcv(struct sk_buff *skb)
674{
675	const struct iphdr *iph = ip_hdr(skb);
676	struct ip_tunnel *tunnel;
677	int sifindex;
678	int err;
679
680	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
681	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
682				     iph->saddr, iph->daddr, sifindex);
683	if (tunnel) {
684		struct pcpu_sw_netstats *tstats;
685
686		if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
687		    tunnel->parms.iph.protocol != 0)
688			goto out;
689
690		skb->mac_header = skb->network_header;
691		skb_reset_network_header(skb);
692		IPCB(skb)->flags = 0;
693		skb->dev = tunnel->dev;
694
695		if (packet_is_spoofed(skb, iph, tunnel)) {
696			tunnel->dev->stats.rx_errors++;
697			goto out;
698		}
699
700		if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
701		    !net_eq(tunnel->net, dev_net(tunnel->dev))))
702			goto out;
703
704		/* skb can be uncloned in iptunnel_pull_header, so
705		 * old iph is no longer valid
706		 */
707		iph = (const struct iphdr *)skb_mac_header(skb);
708		err = IP_ECN_decapsulate(iph, skb);
709		if (unlikely(err)) {
710			if (log_ecn_error)
711				net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
712						     &iph->saddr, iph->tos);
713			if (err > 1) {
714				++tunnel->dev->stats.rx_frame_errors;
715				++tunnel->dev->stats.rx_errors;
716				goto out;
717			}
718		}
719
720		tstats = this_cpu_ptr(tunnel->dev->tstats);
721		u64_stats_update_begin(&tstats->syncp);
722		tstats->rx_packets++;
723		tstats->rx_bytes += skb->len;
724		u64_stats_update_end(&tstats->syncp);
725
726		netif_rx(skb);
727
728		return 0;
729	}
730
731	/* no tunnel matched,  let upstream know, ipsec may handle it */
732	return 1;
733out:
734	kfree_skb(skb);
735	return 0;
736}
737
738static const struct tnl_ptk_info ipip_tpi = {
739	/* no tunnel info required for ipip. */
740	.proto = htons(ETH_P_IP),
741};
742
743#if IS_ENABLED(CONFIG_MPLS)
744static const struct tnl_ptk_info mplsip_tpi = {
745	/* no tunnel info required for mplsip. */
746	.proto = htons(ETH_P_MPLS_UC),
747};
748#endif
749
750static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
751{
752	const struct iphdr *iph;
753	struct ip_tunnel *tunnel;
754	int sifindex;
755
756	sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
757
758	iph = ip_hdr(skb);
759	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
760				     iph->saddr, iph->daddr, sifindex);
761	if (tunnel) {
762		const struct tnl_ptk_info *tpi;
763
764		if (tunnel->parms.iph.protocol != ipproto &&
765		    tunnel->parms.iph.protocol != 0)
766			goto drop;
767
768		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
769			goto drop;
770#if IS_ENABLED(CONFIG_MPLS)
771		if (ipproto == IPPROTO_MPLS)
772			tpi = &mplsip_tpi;
773		else
774#endif
775			tpi = &ipip_tpi;
776		if (iptunnel_pull_header(skb, 0, tpi->proto, false))
777			goto drop;
778		return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
779	}
780
781	return 1;
782
783drop:
784	kfree_skb(skb);
785	return 0;
786}
787
788static int ipip_rcv(struct sk_buff *skb)
789{
790	return sit_tunnel_rcv(skb, IPPROTO_IPIP);
791}
792
793#if IS_ENABLED(CONFIG_MPLS)
794static int mplsip_rcv(struct sk_buff *skb)
795{
796	return sit_tunnel_rcv(skb, IPPROTO_MPLS);
797}
798#endif
799
800/*
801 * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
802 * stores the embedded IPv4 address in v4dst and returns true.
803 */
804static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
805		      __be32 *v4dst)
806{
807#ifdef CONFIG_IPV6_SIT_6RD
808	if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
809			      tunnel->ip6rd.prefixlen)) {
810		unsigned int pbw0, pbi0;
811		int pbi1;
812		u32 d;
813
814		pbw0 = tunnel->ip6rd.prefixlen >> 5;
815		pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
816
817		d = tunnel->ip6rd.relay_prefixlen < 32 ?
818			(ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
819		    tunnel->ip6rd.relay_prefixlen : 0;
820
821		pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
822		if (pbi1 > 0)
823			d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
824			     (32 - pbi1);
825
826		*v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
827		return true;
828	}
829#else
830	if (v6dst->s6_addr16[0] == htons(0x2002)) {
831		/* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
832		memcpy(v4dst, &v6dst->s6_addr16[1], 4);
833		return true;
834	}
835#endif
836	return false;
837}
838
839static inline __be32 try_6rd(struct ip_tunnel *tunnel,
840			     const struct in6_addr *v6dst)
841{
842	__be32 dst = 0;
843	check_6rd(tunnel, v6dst, &dst);
844	return dst;
845}
846
847/*
848 *	This function assumes it is being called from dev_queue_xmit()
849 *	and that skb is filled properly by that function.
850 */
851
852static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
853				     struct net_device *dev)
854{
855	struct ip_tunnel *tunnel = netdev_priv(dev);
856	const struct iphdr  *tiph = &tunnel->parms.iph;
857	const struct ipv6hdr *iph6 = ipv6_hdr(skb);
858	u8     tos = tunnel->parms.iph.tos;
859	__be16 df = tiph->frag_off;
860	struct rtable *rt;		/* Route to the other host */
861	struct net_device *tdev;	/* Device to other host */
862	unsigned int max_headroom;	/* The extra header space needed */
863	__be32 dst = tiph->daddr;
864	struct flowi4 fl4;
865	int    mtu;
866	const struct in6_addr *addr6;
867	int addr_type;
868	u8 ttl;
869	u8 protocol = IPPROTO_IPV6;
870	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
871
872	if (tos == 1)
873		tos = ipv6_get_dsfield(iph6);
874
875	/* ISATAP (RFC4214) - must come before 6to4 */
876	if (dev->priv_flags & IFF_ISATAP) {
877		struct neighbour *neigh = NULL;
878		bool do_tx_error = false;
879
880		if (skb_dst(skb))
881			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
882
883		if (!neigh) {
884			net_dbg_ratelimited("nexthop == NULL\n");
885			goto tx_error;
886		}
887
888		addr6 = (const struct in6_addr *)&neigh->primary_key;
889		addr_type = ipv6_addr_type(addr6);
890
891		if ((addr_type & IPV6_ADDR_UNICAST) &&
892		     ipv6_addr_is_isatap(addr6))
893			dst = addr6->s6_addr32[3];
894		else
895			do_tx_error = true;
896
897		neigh_release(neigh);
898		if (do_tx_error)
899			goto tx_error;
900	}
901
902	if (!dst)
903		dst = try_6rd(tunnel, &iph6->daddr);
904
905	if (!dst) {
906		struct neighbour *neigh = NULL;
907		bool do_tx_error = false;
908
909		if (skb_dst(skb))
910			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
911
912		if (!neigh) {
913			net_dbg_ratelimited("nexthop == NULL\n");
914			goto tx_error;
915		}
916
917		addr6 = (const struct in6_addr *)&neigh->primary_key;
918		addr_type = ipv6_addr_type(addr6);
919
920		if (addr_type == IPV6_ADDR_ANY) {
921			addr6 = &ipv6_hdr(skb)->daddr;
922			addr_type = ipv6_addr_type(addr6);
923		}
924
925		if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
926			dst = addr6->s6_addr32[3];
927		else
928			do_tx_error = true;
929
930		neigh_release(neigh);
931		if (do_tx_error)
932			goto tx_error;
933	}
934
935	flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
936			   RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
937			   0, dst, tiph->saddr, 0, 0,
938			   sock_net_uid(tunnel->net, NULL));
939
940	rt = dst_cache_get_ip4(&tunnel->dst_cache, &fl4.saddr);
941	if (!rt) {
942		rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
943		if (IS_ERR(rt)) {
944			dev->stats.tx_carrier_errors++;
945			goto tx_error_icmp;
946		}
947		dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr);
948	}
949
950	if (rt->rt_type != RTN_UNICAST) {
951		ip_rt_put(rt);
952		dev->stats.tx_carrier_errors++;
953		goto tx_error_icmp;
954	}
955	tdev = rt->dst.dev;
956
957	if (tdev == dev) {
958		ip_rt_put(rt);
959		dev->stats.collisions++;
960		goto tx_error;
961	}
962
963	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
964		ip_rt_put(rt);
965		goto tx_error;
966	}
967
968	if (df) {
969		mtu = dst_mtu(&rt->dst) - t_hlen;
970
971		if (mtu < 68) {
972			dev->stats.collisions++;
973			ip_rt_put(rt);
974			goto tx_error;
975		}
976
977		if (mtu < IPV6_MIN_MTU) {
978			mtu = IPV6_MIN_MTU;
979			df = 0;
980		}
981
982		if (tunnel->parms.iph.daddr)
983			skb_dst_update_pmtu_no_confirm(skb, mtu);
984
985		if (skb->len > mtu && !skb_is_gso(skb)) {
986			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
987			ip_rt_put(rt);
988			goto tx_error;
989		}
990	}
991
992	if (tunnel->err_count > 0) {
993		if (time_before(jiffies,
994				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
995			tunnel->err_count--;
996			dst_link_failure(skb);
997		} else
998			tunnel->err_count = 0;
999	}
1000
1001	/*
1002	 * Okay, now see if we can stuff it in the buffer as-is.
1003	 */
1004	max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
1005
1006	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1007	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1008		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
1009		if (!new_skb) {
1010			ip_rt_put(rt);
1011			dev->stats.tx_dropped++;
1012			kfree_skb(skb);
1013			return NETDEV_TX_OK;
1014		}
1015		if (skb->sk)
1016			skb_set_owner_w(new_skb, skb->sk);
1017		dev_kfree_skb(skb);
1018		skb = new_skb;
1019		iph6 = ipv6_hdr(skb);
1020	}
1021	ttl = tiph->ttl;
1022	if (ttl == 0)
1023		ttl = iph6->hop_limit;
1024	tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
1025
1026	if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
1027		ip_rt_put(rt);
1028		goto tx_error;
1029	}
1030
1031	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
1032
1033	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
1034		      df, !net_eq(tunnel->net, dev_net(dev)));
1035	return NETDEV_TX_OK;
1036
1037tx_error_icmp:
1038	dst_link_failure(skb);
1039tx_error:
1040	kfree_skb(skb);
1041	dev->stats.tx_errors++;
1042	return NETDEV_TX_OK;
1043}
1044
1045static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
1046				     struct net_device *dev, u8 ipproto)
1047{
1048	struct ip_tunnel *tunnel = netdev_priv(dev);
1049	const struct iphdr  *tiph = &tunnel->parms.iph;
1050
1051	if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1052		goto tx_error;
1053
1054	skb_set_inner_ipproto(skb, ipproto);
1055
1056	ip_tunnel_xmit(skb, dev, tiph, ipproto);
1057	return NETDEV_TX_OK;
1058tx_error:
1059	kfree_skb(skb);
1060	dev->stats.tx_errors++;
1061	return NETDEV_TX_OK;
1062}
1063
1064static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1065				   struct net_device *dev)
1066{
1067	if (!pskb_inet_may_pull(skb))
1068		goto tx_err;
1069
1070	switch (skb->protocol) {
1071	case htons(ETH_P_IP):
1072		sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1073		break;
1074	case htons(ETH_P_IPV6):
1075		ipip6_tunnel_xmit(skb, dev);
1076		break;
1077#if IS_ENABLED(CONFIG_MPLS)
1078	case htons(ETH_P_MPLS_UC):
1079		sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1080		break;
1081#endif
1082	default:
1083		goto tx_err;
1084	}
1085
1086	return NETDEV_TX_OK;
1087
1088tx_err:
1089	dev->stats.tx_errors++;
1090	kfree_skb(skb);
1091	return NETDEV_TX_OK;
1092
1093}
1094
1095static void ipip6_tunnel_bind_dev(struct net_device *dev)
1096{
1097	struct ip_tunnel *tunnel = netdev_priv(dev);
1098	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1099	struct net_device *tdev = NULL;
1100	int hlen = LL_MAX_HEADER;
1101	const struct iphdr *iph;
1102	struct flowi4 fl4;
1103
1104	iph = &tunnel->parms.iph;
1105
1106	if (iph->daddr) {
1107		struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1108							  NULL,
1109							  iph->daddr, iph->saddr,
1110							  0, 0,
1111							  IPPROTO_IPV6,
1112							  RT_TOS(iph->tos),
1113							  tunnel->parms.link);
1114
1115		if (!IS_ERR(rt)) {
1116			tdev = rt->dst.dev;
1117			ip_rt_put(rt);
1118		}
1119		dev->flags |= IFF_POINTOPOINT;
1120	}
1121
1122	if (!tdev && tunnel->parms.link)
1123		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1124
1125	if (tdev && !netif_is_l3_master(tdev)) {
1126		int mtu;
1127
1128		mtu = tdev->mtu - t_hlen;
1129		if (mtu < IPV6_MIN_MTU)
1130			mtu = IPV6_MIN_MTU;
1131		WRITE_ONCE(dev->mtu, mtu);
1132		hlen = tdev->hard_header_len + tdev->needed_headroom;
1133	}
1134	dev->needed_headroom = t_hlen + hlen;
1135}
1136
1137static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
1138				__u32 fwmark)
1139{
1140	struct net *net = t->net;
1141	struct sit_net *sitn = net_generic(net, sit_net_id);
1142
1143	ipip6_tunnel_unlink(sitn, t);
1144	synchronize_net();
1145	t->parms.iph.saddr = p->iph.saddr;
1146	t->parms.iph.daddr = p->iph.daddr;
1147	memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1148	memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1149	ipip6_tunnel_link(sitn, t);
1150	t->parms.iph.ttl = p->iph.ttl;
1151	t->parms.iph.tos = p->iph.tos;
1152	t->parms.iph.frag_off = p->iph.frag_off;
1153	if (t->parms.link != p->link || t->fwmark != fwmark) {
1154		t->parms.link = p->link;
1155		t->fwmark = fwmark;
1156		ipip6_tunnel_bind_dev(t->dev);
1157	}
1158	dst_cache_reset(&t->dst_cache);
1159	netdev_state_change(t->dev);
1160}
1161
1162#ifdef CONFIG_IPV6_SIT_6RD
1163static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1164				   struct ip_tunnel_6rd *ip6rd)
1165{
1166	struct in6_addr prefix;
1167	__be32 relay_prefix;
1168
1169	if (ip6rd->relay_prefixlen > 32 ||
1170	    ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1171		return -EINVAL;
1172
1173	ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1174	if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1175		return -EINVAL;
1176	if (ip6rd->relay_prefixlen)
1177		relay_prefix = ip6rd->relay_prefix &
1178			       htonl(0xffffffffUL <<
1179				     (32 - ip6rd->relay_prefixlen));
1180	else
1181		relay_prefix = 0;
1182	if (relay_prefix != ip6rd->relay_prefix)
1183		return -EINVAL;
1184
1185	t->ip6rd.prefix = prefix;
1186	t->ip6rd.relay_prefix = relay_prefix;
1187	t->ip6rd.prefixlen = ip6rd->prefixlen;
1188	t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1189	dst_cache_reset(&t->dst_cache);
1190	netdev_state_change(t->dev);
1191	return 0;
1192}
1193
1194static int
1195ipip6_tunnel_get6rd(struct net_device *dev, struct ifreq *ifr)
1196{
1197	struct ip_tunnel *t = netdev_priv(dev);
1198	struct ip_tunnel_6rd ip6rd;
1199	struct ip_tunnel_parm p;
1200
1201	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1202		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1203			return -EFAULT;
1204		t = ipip6_tunnel_locate(t->net, &p, 0);
1205	}
1206	if (!t)
1207		t = netdev_priv(dev);
1208
1209	ip6rd.prefix = t->ip6rd.prefix;
1210	ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1211	ip6rd.prefixlen = t->ip6rd.prefixlen;
1212	ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1213	if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd, sizeof(ip6rd)))
1214		return -EFAULT;
1215	return 0;
1216}
1217
1218static int
1219ipip6_tunnel_6rdctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1220{
1221	struct ip_tunnel *t = netdev_priv(dev);
1222	struct ip_tunnel_6rd ip6rd;
1223	int err;
1224
1225	if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1226		return -EPERM;
1227	if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data, sizeof(ip6rd)))
1228		return -EFAULT;
1229
1230	if (cmd != SIOCDEL6RD) {
1231		err = ipip6_tunnel_update_6rd(t, &ip6rd);
1232		if (err < 0)
1233			return err;
1234	} else
1235		ipip6_tunnel_clone_6rd(dev, dev_to_sit_net(dev));
1236	return 0;
1237}
1238
1239#endif /* CONFIG_IPV6_SIT_6RD */
1240
1241static bool ipip6_valid_ip_proto(u8 ipproto)
1242{
1243	return ipproto == IPPROTO_IPV6 ||
1244		ipproto == IPPROTO_IPIP ||
1245#if IS_ENABLED(CONFIG_MPLS)
1246		ipproto == IPPROTO_MPLS ||
1247#endif
1248		ipproto == 0;
1249}
1250
1251static int
1252__ipip6_tunnel_ioctl_validate(struct net *net, struct ip_tunnel_parm *p)
1253{
1254	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1255		return -EPERM;
1256
1257	if (!ipip6_valid_ip_proto(p->iph.protocol))
1258		return -EINVAL;
1259	if (p->iph.version != 4 ||
1260	    p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)))
1261		return -EINVAL;
1262
1263	if (p->iph.ttl)
1264		p->iph.frag_off |= htons(IP_DF);
1265	return 0;
1266}
1267
1268static int
1269ipip6_tunnel_get(struct net_device *dev, struct ip_tunnel_parm *p)
1270{
1271	struct ip_tunnel *t = netdev_priv(dev);
1272
1273	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
1274		t = ipip6_tunnel_locate(t->net, p, 0);
1275	if (!t)
1276		t = netdev_priv(dev);
1277	memcpy(p, &t->parms, sizeof(*p));
1278	return 0;
1279}
1280
1281static int
1282ipip6_tunnel_add(struct net_device *dev, struct ip_tunnel_parm *p)
1283{
1284	struct ip_tunnel *t = netdev_priv(dev);
1285	int err;
1286
1287	err = __ipip6_tunnel_ioctl_validate(t->net, p);
1288	if (err)
1289		return err;
1290
1291	t = ipip6_tunnel_locate(t->net, p, 1);
1292	if (!t)
1293		return -ENOBUFS;
1294	return 0;
1295}
1296
1297static int
1298ipip6_tunnel_change(struct net_device *dev, struct ip_tunnel_parm *p)
1299{
1300	struct ip_tunnel *t = netdev_priv(dev);
1301	int err;
1302
1303	err = __ipip6_tunnel_ioctl_validate(t->net, p);
1304	if (err)
1305		return err;
1306
1307	t = ipip6_tunnel_locate(t->net, p, 0);
1308	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1309		if (!t)
1310			return -ENOENT;
1311	} else {
1312		if (t) {
1313			if (t->dev != dev)
1314				return -EEXIST;
1315		} else {
1316			if (((dev->flags & IFF_POINTOPOINT) && !p->iph.daddr) ||
1317			    (!(dev->flags & IFF_POINTOPOINT) && p->iph.daddr))
1318				return -EINVAL;
1319			t = netdev_priv(dev);
1320		}
1321
1322		ipip6_tunnel_update(t, p, t->fwmark);
1323	}
1324
1325	return 0;
1326}
1327
1328static int
1329ipip6_tunnel_del(struct net_device *dev, struct ip_tunnel_parm *p)
1330{
1331	struct ip_tunnel *t = netdev_priv(dev);
1332
1333	if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1334		return -EPERM;
1335
1336	if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1337		t = ipip6_tunnel_locate(t->net, p, 0);
1338		if (!t)
1339			return -ENOENT;
1340		if (t == netdev_priv(dev_to_sit_net(dev)->fb_tunnel_dev))
1341			return -EPERM;
1342		dev = t->dev;
1343	}
1344	unregister_netdevice(dev);
1345	return 0;
1346}
1347
1348static int
1349ipip6_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
1350{
1351	switch (cmd) {
1352	case SIOCGETTUNNEL:
1353		return ipip6_tunnel_get(dev, p);
1354	case SIOCADDTUNNEL:
1355		return ipip6_tunnel_add(dev, p);
1356	case SIOCCHGTUNNEL:
1357		return ipip6_tunnel_change(dev, p);
1358	case SIOCDELTUNNEL:
1359		return ipip6_tunnel_del(dev, p);
1360	default:
1361		return -EINVAL;
1362	}
1363}
1364
1365static int
1366ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1367{
1368	switch (cmd) {
1369	case SIOCGETTUNNEL:
1370	case SIOCADDTUNNEL:
1371	case SIOCCHGTUNNEL:
1372	case SIOCDELTUNNEL:
1373		return ip_tunnel_ioctl(dev, ifr, cmd);
1374	case SIOCGETPRL:
1375		return ipip6_tunnel_get_prl(dev, ifr);
1376	case SIOCADDPRL:
1377	case SIOCDELPRL:
1378	case SIOCCHGPRL:
1379		return ipip6_tunnel_prl_ctl(dev, ifr, cmd);
1380#ifdef CONFIG_IPV6_SIT_6RD
1381	case SIOCGET6RD:
1382		return ipip6_tunnel_get6rd(dev, ifr);
1383	case SIOCADD6RD:
1384	case SIOCCHG6RD:
1385	case SIOCDEL6RD:
1386		return ipip6_tunnel_6rdctl(dev, ifr, cmd);
1387#endif
1388	default:
1389		return -EINVAL;
1390	}
1391}
1392
1393static const struct net_device_ops ipip6_netdev_ops = {
1394	.ndo_init	= ipip6_tunnel_init,
1395	.ndo_uninit	= ipip6_tunnel_uninit,
1396	.ndo_start_xmit	= sit_tunnel_xmit,
1397	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
1398	.ndo_get_stats64 = ip_tunnel_get_stats64,
1399	.ndo_get_iflink = ip_tunnel_get_iflink,
1400	.ndo_tunnel_ctl = ipip6_tunnel_ctl,
1401};
1402
1403static void ipip6_dev_free(struct net_device *dev)
1404{
1405	struct ip_tunnel *tunnel = netdev_priv(dev);
1406
1407	dst_cache_destroy(&tunnel->dst_cache);
1408	free_percpu(dev->tstats);
1409}
1410
1411#define SIT_FEATURES (NETIF_F_SG	   | \
1412		      NETIF_F_FRAGLIST	   | \
1413		      NETIF_F_HIGHDMA	   | \
1414		      NETIF_F_GSO_SOFTWARE | \
1415		      NETIF_F_HW_CSUM)
1416
1417static void ipip6_tunnel_setup(struct net_device *dev)
1418{
1419	struct ip_tunnel *tunnel = netdev_priv(dev);
1420	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1421
1422	dev->netdev_ops		= &ipip6_netdev_ops;
1423	dev->header_ops		= &ip_tunnel_header_ops;
1424	dev->needs_free_netdev	= true;
1425	dev->priv_destructor	= ipip6_dev_free;
1426
1427	dev->type		= ARPHRD_SIT;
1428	dev->mtu		= ETH_DATA_LEN - t_hlen;
1429	dev->min_mtu		= IPV6_MIN_MTU;
1430	dev->max_mtu		= IP6_MAX_MTU - t_hlen;
1431	dev->flags		= IFF_NOARP;
1432	netif_keep_dst(dev);
1433	dev->addr_len		= 4;
1434	dev->features		|= NETIF_F_LLTX;
1435	dev->features		|= SIT_FEATURES;
1436	dev->hw_features	|= SIT_FEATURES;
1437}
1438
1439static int ipip6_tunnel_init(struct net_device *dev)
1440{
1441	struct ip_tunnel *tunnel = netdev_priv(dev);
1442	int err;
1443
1444	tunnel->dev = dev;
1445	tunnel->net = dev_net(dev);
1446	strcpy(tunnel->parms.name, dev->name);
1447
1448	ipip6_tunnel_bind_dev(dev);
1449	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1450	if (!dev->tstats)
1451		return -ENOMEM;
1452
1453	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1454	if (err) {
1455		free_percpu(dev->tstats);
1456		dev->tstats = NULL;
1457		return err;
1458	}
1459	dev_hold(dev);
1460	return 0;
1461}
1462
1463static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1464{
1465	struct ip_tunnel *tunnel = netdev_priv(dev);
1466	struct iphdr *iph = &tunnel->parms.iph;
1467	struct net *net = dev_net(dev);
1468	struct sit_net *sitn = net_generic(net, sit_net_id);
1469
1470	iph->version		= 4;
1471	iph->protocol		= IPPROTO_IPV6;
1472	iph->ihl		= 5;
1473	iph->ttl		= 64;
1474
1475	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1476}
1477
1478static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1479			  struct netlink_ext_ack *extack)
1480{
1481	u8 proto;
1482
1483	if (!data || !data[IFLA_IPTUN_PROTO])
1484		return 0;
1485
1486	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1487	if (!ipip6_valid_ip_proto(proto))
1488		return -EINVAL;
1489
1490	return 0;
1491}
1492
1493static void ipip6_netlink_parms(struct nlattr *data[],
1494				struct ip_tunnel_parm *parms,
1495				__u32 *fwmark)
1496{
1497	memset(parms, 0, sizeof(*parms));
1498
1499	parms->iph.version = 4;
1500	parms->iph.protocol = IPPROTO_IPV6;
1501	parms->iph.ihl = 5;
1502	parms->iph.ttl = 64;
1503
1504	if (!data)
1505		return;
1506
1507	if (data[IFLA_IPTUN_LINK])
1508		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1509
1510	if (data[IFLA_IPTUN_LOCAL])
1511		parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1512
1513	if (data[IFLA_IPTUN_REMOTE])
1514		parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1515
1516	if (data[IFLA_IPTUN_TTL]) {
1517		parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1518		if (parms->iph.ttl)
1519			parms->iph.frag_off = htons(IP_DF);
1520	}
1521
1522	if (data[IFLA_IPTUN_TOS])
1523		parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1524
1525	if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1526		parms->iph.frag_off = htons(IP_DF);
1527
1528	if (data[IFLA_IPTUN_FLAGS])
1529		parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1530
1531	if (data[IFLA_IPTUN_PROTO])
1532		parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1533
1534	if (data[IFLA_IPTUN_FWMARK])
1535		*fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1536}
1537
1538/* This function returns true when ENCAP attributes are present in the nl msg */
1539static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1540				      struct ip_tunnel_encap *ipencap)
1541{
1542	bool ret = false;
1543
1544	memset(ipencap, 0, sizeof(*ipencap));
1545
1546	if (!data)
1547		return ret;
1548
1549	if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1550		ret = true;
1551		ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1552	}
1553
1554	if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1555		ret = true;
1556		ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1557	}
1558
1559	if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1560		ret = true;
1561		ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1562	}
1563
1564	if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1565		ret = true;
1566		ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1567	}
1568
1569	return ret;
1570}
1571
1572#ifdef CONFIG_IPV6_SIT_6RD
1573/* This function returns true when 6RD attributes are present in the nl msg */
1574static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1575				    struct ip_tunnel_6rd *ip6rd)
1576{
1577	bool ret = false;
1578	memset(ip6rd, 0, sizeof(*ip6rd));
1579
1580	if (!data)
1581		return ret;
1582
1583	if (data[IFLA_IPTUN_6RD_PREFIX]) {
1584		ret = true;
1585		ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1586	}
1587
1588	if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1589		ret = true;
1590		ip6rd->relay_prefix =
1591			nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1592	}
1593
1594	if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1595		ret = true;
1596		ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1597	}
1598
1599	if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1600		ret = true;
1601		ip6rd->relay_prefixlen =
1602			nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1603	}
1604
1605	return ret;
1606}
1607#endif
1608
1609static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1610			 struct nlattr *tb[], struct nlattr *data[],
1611			 struct netlink_ext_ack *extack)
1612{
1613	struct net *net = dev_net(dev);
1614	struct ip_tunnel *nt;
1615	struct ip_tunnel_encap ipencap;
1616#ifdef CONFIG_IPV6_SIT_6RD
1617	struct ip_tunnel_6rd ip6rd;
1618#endif
1619	int err;
1620
1621	nt = netdev_priv(dev);
1622
1623	if (ipip6_netlink_encap_parms(data, &ipencap)) {
1624		err = ip_tunnel_encap_setup(nt, &ipencap);
1625		if (err < 0)
1626			return err;
1627	}
1628
1629	ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1630
1631	if (ipip6_tunnel_locate(net, &nt->parms, 0))
1632		return -EEXIST;
1633
1634	err = ipip6_tunnel_create(dev);
1635	if (err < 0)
1636		return err;
1637
1638	if (tb[IFLA_MTU]) {
1639		u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1640
1641		if (mtu >= IPV6_MIN_MTU &&
1642		    mtu <= IP6_MAX_MTU - dev->hard_header_len)
1643			dev->mtu = mtu;
1644	}
1645
1646#ifdef CONFIG_IPV6_SIT_6RD
1647	if (ipip6_netlink_6rd_parms(data, &ip6rd)) {
1648		err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1649		if (err < 0)
1650			unregister_netdevice_queue(dev, NULL);
1651	}
1652#endif
1653
1654	return err;
1655}
1656
1657static 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
1705static 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
1747static 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
1788nla_put_failure:
1789	return -EMSGSIZE;
1790}
1791
1792static 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
1814static 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
1823static 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
1838static struct xfrm_tunnel sit_handler __read_mostly = {
1839	.handler	=	ipip6_rcv,
1840	.err_handler	=	ipip6_err,
1841	.priority	=	1,
1842};
1843
1844static 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)
1851static struct xfrm_tunnel mplsip_handler __read_mostly = {
1852	.handler	=	mplsip_rcv,
1853	.err_handler	=	ipip6_err,
1854	.priority	=	2,
1855};
1856#endif
1857
1858static 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 = 0; prio < 4; prio++) {
1870		int h;
1871		for (h = 0; h < (prio ? IP6_SIT_HASH_SIZE : 1); 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
1888static 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
1928err_reg_dev:
1929	free_netdev(sitn->fb_tunnel_dev);
1930err_alloc_dev:
1931	return err;
1932}
1933
1934static void __net_exit sit_exit_batch_net(struct list_head *net_list)
1935{
1936	LIST_HEAD(list);
1937	struct net *net;
1938
1939	rtnl_lock();
1940	list_for_each_entry(net, net_list, exit_list)
1941		sit_destroy_tunnels(net, &list);
1942
1943	unregister_netdevice_many(&list);
1944	rtnl_unlock();
1945}
1946
1947static struct pernet_operations sit_net_ops = {
1948	.init = sit_init_net,
1949	.exit_batch = sit_exit_batch_net,
1950	.id   = &sit_net_id,
1951	.size = sizeof(struct sit_net),
1952};
1953
1954static void __exit sit_cleanup(void)
1955{
1956	rtnl_link_unregister(&sit_link_ops);
1957	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1958	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1959#if IS_ENABLED(CONFIG_MPLS)
1960	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1961#endif
1962
1963	unregister_pernet_device(&sit_net_ops);
1964	rcu_barrier(); /* Wait for completion of call_rcu()'s */
1965}
1966
1967static int __init sit_init(void)
1968{
1969	int err;
1970
1971	pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1972
1973	err = register_pernet_device(&sit_net_ops);
1974	if (err < 0)
1975		return err;
1976	err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1977	if (err < 0) {
1978		pr_info("%s: can't register ip6ip4\n", __func__);
1979		goto xfrm_tunnel_failed;
1980	}
1981	err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1982	if (err < 0) {
1983		pr_info("%s: can't register ip4ip4\n", __func__);
1984		goto xfrm_tunnel4_failed;
1985	}
1986#if IS_ENABLED(CONFIG_MPLS)
1987	err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1988	if (err < 0) {
1989		pr_info("%s: can't register mplsip\n", __func__);
1990		goto xfrm_tunnel_mpls_failed;
1991	}
1992#endif
1993	err = rtnl_link_register(&sit_link_ops);
1994	if (err < 0)
1995		goto rtnl_link_failed;
1996
1997out:
1998	return err;
1999
2000rtnl_link_failed:
2001#if IS_ENABLED(CONFIG_MPLS)
2002	xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
2003xfrm_tunnel_mpls_failed:
2004#endif
2005	xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
2006xfrm_tunnel4_failed:
2007	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
2008xfrm_tunnel_failed:
2009	unregister_pernet_device(&sit_net_ops);
2010	goto out;
2011}
2012
2013module_init(sit_init);
2014module_exit(sit_cleanup);
2015MODULE_LICENSE("GPL");
2016MODULE_ALIAS_RTNL_LINK("sit");
2017MODULE_ALIAS_NETDEV("sit0");
2018