xref: /linux/net/ipv4/ip_tunnel.c (revision e7cd4b811c9e019f5acbce85699c622b30194c24)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2013 Nicira, Inc.
4  */
5 
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7 
8 #include <linux/capability.h>
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/uaccess.h>
14 #include <linux/skbuff.h>
15 #include <linux/netdevice.h>
16 #include <linux/in.h>
17 #include <linux/tcp.h>
18 #include <linux/udp.h>
19 #include <linux/if_arp.h>
20 #include <linux/init.h>
21 #include <linux/in6.h>
22 #include <linux/inetdevice.h>
23 #include <linux/igmp.h>
24 #include <linux/netfilter_ipv4.h>
25 #include <linux/etherdevice.h>
26 #include <linux/if_ether.h>
27 #include <linux/if_vlan.h>
28 #include <linux/rculist.h>
29 #include <linux/err.h>
30 
31 #include <net/sock.h>
32 #include <net/ip.h>
33 #include <net/icmp.h>
34 #include <net/protocol.h>
35 #include <net/ip_tunnels.h>
36 #include <net/arp.h>
37 #include <net/checksum.h>
38 #include <net/dsfield.h>
39 #include <net/inet_ecn.h>
40 #include <net/xfrm.h>
41 #include <net/net_namespace.h>
42 #include <net/netns/generic.h>
43 #include <net/rtnetlink.h>
44 #include <net/udp.h>
45 #include <net/dst_metadata.h>
46 #include <net/inet_dscp.h>
47 
48 #if IS_ENABLED(CONFIG_IPV6)
49 #include <net/ipv6.h>
50 #include <net/ip6_fib.h>
51 #include <net/ip6_route.h>
52 #endif
53 
54 static unsigned int ip_tunnel_hash(__be32 key, __be32 remote)
55 {
56 	return hash_32((__force u32)key ^ (__force u32)remote,
57 			 IP_TNL_HASH_BITS);
58 }
59 
60 static bool ip_tunnel_key_match(const struct ip_tunnel_parm_kern *p,
61 				const unsigned long *flags, __be32 key)
62 {
63 	if (!test_bit(IP_TUNNEL_KEY_BIT, flags))
64 		return !test_bit(IP_TUNNEL_KEY_BIT, p->i_flags);
65 
66 	return test_bit(IP_TUNNEL_KEY_BIT, p->i_flags) && p->i_key == key;
67 }
68 
69 /* Fallback tunnel: no source, no destination, no key, no options
70 
71    Tunnel hash table:
72    We require exact key match i.e. if a key is present in packet
73    it will match only tunnel with the same key; if it is not present,
74    it will match only keyless tunnel.
75 
76    All keysless packets, if not matched configured keyless tunnels
77    will match fallback tunnel.
78    Given src, dst and key, find appropriate for input tunnel.
79 */
80 struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
81 				   int link, const unsigned long *flags,
82 				   __be32 remote, __be32 local,
83 				   __be32 key)
84 {
85 	struct ip_tunnel *t, *cand = NULL;
86 	struct hlist_head *head;
87 	struct net_device *ndev;
88 	unsigned int hash;
89 
90 	hash = ip_tunnel_hash(key, remote);
91 	head = &itn->tunnels[hash];
92 
93 	hlist_for_each_entry_rcu(t, head, hash_node) {
94 		if (local != t->parms.iph.saddr ||
95 		    remote != t->parms.iph.daddr ||
96 		    !(t->dev->flags & IFF_UP))
97 			continue;
98 
99 		if (!ip_tunnel_key_match(&t->parms, flags, key))
100 			continue;
101 
102 		if (READ_ONCE(t->parms.link) == link)
103 			return t;
104 		cand = t;
105 	}
106 
107 	hlist_for_each_entry_rcu(t, head, hash_node) {
108 		if (remote != t->parms.iph.daddr ||
109 		    t->parms.iph.saddr != 0 ||
110 		    !(t->dev->flags & IFF_UP))
111 			continue;
112 
113 		if (!ip_tunnel_key_match(&t->parms, flags, key))
114 			continue;
115 
116 		if (READ_ONCE(t->parms.link) == link)
117 			return t;
118 		if (!cand)
119 			cand = t;
120 	}
121 
122 	hash = ip_tunnel_hash(key, 0);
123 	head = &itn->tunnels[hash];
124 
125 	hlist_for_each_entry_rcu(t, head, hash_node) {
126 		if ((local != t->parms.iph.saddr || t->parms.iph.daddr != 0) &&
127 		    (local != t->parms.iph.daddr || !ipv4_is_multicast(local)))
128 			continue;
129 
130 		if (!(t->dev->flags & IFF_UP))
131 			continue;
132 
133 		if (!ip_tunnel_key_match(&t->parms, flags, key))
134 			continue;
135 
136 		if (READ_ONCE(t->parms.link) == link)
137 			return t;
138 		if (!cand)
139 			cand = t;
140 	}
141 
142 	hlist_for_each_entry_rcu(t, head, hash_node) {
143 		if ((!test_bit(IP_TUNNEL_NO_KEY_BIT, flags) &&
144 		     t->parms.i_key != key) ||
145 		    t->parms.iph.saddr != 0 ||
146 		    t->parms.iph.daddr != 0 ||
147 		    !(t->dev->flags & IFF_UP))
148 			continue;
149 
150 		if (READ_ONCE(t->parms.link) == link)
151 			return t;
152 		if (!cand)
153 			cand = t;
154 	}
155 
156 	if (cand)
157 		return cand;
158 
159 	t = rcu_dereference(itn->collect_md_tun);
160 	if (t && t->dev->flags & IFF_UP)
161 		return t;
162 
163 	ndev = READ_ONCE(itn->fb_tunnel_dev);
164 	if (ndev && ndev->flags & IFF_UP)
165 		return netdev_priv(ndev);
166 
167 	return NULL;
168 }
169 EXPORT_SYMBOL_GPL(ip_tunnel_lookup);
170 
171 static struct hlist_head *ip_bucket(struct ip_tunnel_net *itn,
172 				    struct ip_tunnel_parm_kern *parms)
173 {
174 	unsigned int h;
175 	__be32 remote;
176 	__be32 i_key = parms->i_key;
177 
178 	if (parms->iph.daddr && !ipv4_is_multicast(parms->iph.daddr))
179 		remote = parms->iph.daddr;
180 	else
181 		remote = 0;
182 
183 	if (!test_bit(IP_TUNNEL_KEY_BIT, parms->i_flags) &&
184 	    test_bit(IP_TUNNEL_VTI_BIT, parms->i_flags))
185 		i_key = 0;
186 
187 	h = ip_tunnel_hash(i_key, remote);
188 	return &itn->tunnels[h];
189 }
190 
191 static void ip_tunnel_add(struct ip_tunnel_net *itn, struct ip_tunnel *t)
192 {
193 	struct hlist_head *head = ip_bucket(itn, &t->parms);
194 
195 	if (t->collect_md)
196 		rcu_assign_pointer(itn->collect_md_tun, t);
197 	hlist_add_head_rcu(&t->hash_node, head);
198 }
199 
200 static void ip_tunnel_del(struct ip_tunnel_net *itn, struct ip_tunnel *t)
201 {
202 	if (t->collect_md)
203 		rcu_assign_pointer(itn->collect_md_tun, NULL);
204 	hlist_del_init_rcu(&t->hash_node);
205 }
206 
207 static struct ip_tunnel *ip_tunnel_find(struct ip_tunnel_net *itn,
208 					struct ip_tunnel_parm_kern *parms,
209 					int type)
210 {
211 	__be32 remote = parms->iph.daddr;
212 	__be32 local = parms->iph.saddr;
213 	IP_TUNNEL_DECLARE_FLAGS(flags);
214 	__be32 key = parms->i_key;
215 	int link = parms->link;
216 	struct ip_tunnel *t = NULL;
217 	struct hlist_head *head = ip_bucket(itn, parms);
218 
219 	ip_tunnel_flags_copy(flags, parms->i_flags);
220 
221 	hlist_for_each_entry_rcu(t, head, hash_node) {
222 		if (local == t->parms.iph.saddr &&
223 		    remote == t->parms.iph.daddr &&
224 		    link == READ_ONCE(t->parms.link) &&
225 		    type == t->dev->type &&
226 		    ip_tunnel_key_match(&t->parms, flags, key))
227 			break;
228 	}
229 	return t;
230 }
231 
232 static struct net_device *__ip_tunnel_create(struct net *net,
233 					     const struct rtnl_link_ops *ops,
234 					     struct ip_tunnel_parm_kern *parms)
235 {
236 	int err;
237 	struct ip_tunnel *tunnel;
238 	struct net_device *dev;
239 	char name[IFNAMSIZ];
240 
241 	err = -E2BIG;
242 	if (parms->name[0]) {
243 		if (!dev_valid_name(parms->name))
244 			goto failed;
245 		strscpy(name, parms->name, IFNAMSIZ);
246 	} else {
247 		if (strlen(ops->kind) > (IFNAMSIZ - 3))
248 			goto failed;
249 		strcpy(name, ops->kind);
250 		strcat(name, "%d");
251 	}
252 
253 	ASSERT_RTNL();
254 	dev = alloc_netdev(ops->priv_size, name, NET_NAME_UNKNOWN, ops->setup);
255 	if (!dev) {
256 		err = -ENOMEM;
257 		goto failed;
258 	}
259 	dev_net_set(dev, net);
260 
261 	dev->rtnl_link_ops = ops;
262 
263 	tunnel = netdev_priv(dev);
264 	tunnel->parms = *parms;
265 	tunnel->net = net;
266 
267 	err = register_netdevice(dev);
268 	if (err)
269 		goto failed_free;
270 
271 	return dev;
272 
273 failed_free:
274 	free_netdev(dev);
275 failed:
276 	return ERR_PTR(err);
277 }
278 
279 static int ip_tunnel_bind_dev(struct net_device *dev)
280 {
281 	struct net_device *tdev = NULL;
282 	struct ip_tunnel *tunnel = netdev_priv(dev);
283 	const struct iphdr *iph;
284 	int hlen = LL_MAX_HEADER;
285 	int mtu = ETH_DATA_LEN;
286 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
287 
288 	iph = &tunnel->parms.iph;
289 
290 	/* Guess output device to choose reasonable mtu and needed_headroom */
291 	if (iph->daddr) {
292 		struct flowi4 fl4;
293 		struct rtable *rt;
294 
295 		ip_tunnel_init_flow(&fl4, iph->protocol, iph->daddr,
296 				    iph->saddr, tunnel->parms.o_key,
297 				    iph->tos & INET_DSCP_MASK, dev_net(dev),
298 				    tunnel->parms.link, tunnel->fwmark, 0, 0);
299 		rt = ip_route_output_key(tunnel->net, &fl4);
300 
301 		if (!IS_ERR(rt)) {
302 			tdev = rt->dst.dev;
303 			ip_rt_put(rt);
304 		}
305 		if (dev->type != ARPHRD_ETHER)
306 			dev->flags |= IFF_POINTOPOINT;
307 
308 		dst_cache_reset(&tunnel->dst_cache);
309 	}
310 
311 	if (!tdev && tunnel->parms.link)
312 		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
313 
314 	if (tdev) {
315 		hlen = tdev->hard_header_len + tdev->needed_headroom;
316 		mtu = min(tdev->mtu, IP_MAX_MTU);
317 	}
318 
319 	dev->needed_headroom = t_hlen + hlen;
320 	mtu -= t_hlen + (dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0);
321 
322 	if (mtu < IPV4_MIN_MTU)
323 		mtu = IPV4_MIN_MTU;
324 
325 	return mtu;
326 }
327 
328 static struct ip_tunnel *ip_tunnel_create(struct net *net,
329 					  struct ip_tunnel_net *itn,
330 					  struct ip_tunnel_parm_kern *parms)
331 {
332 	struct ip_tunnel *nt;
333 	struct net_device *dev;
334 	int t_hlen;
335 	int mtu;
336 	int err;
337 
338 	dev = __ip_tunnel_create(net, itn->rtnl_link_ops, parms);
339 	if (IS_ERR(dev))
340 		return ERR_CAST(dev);
341 
342 	mtu = ip_tunnel_bind_dev(dev);
343 	err = dev_set_mtu(dev, mtu);
344 	if (err)
345 		goto err_dev_set_mtu;
346 
347 	nt = netdev_priv(dev);
348 	t_hlen = nt->hlen + sizeof(struct iphdr);
349 	dev->min_mtu = ETH_MIN_MTU;
350 	dev->max_mtu = IP_MAX_MTU - t_hlen;
351 	if (dev->type == ARPHRD_ETHER)
352 		dev->max_mtu -= dev->hard_header_len;
353 
354 	ip_tunnel_add(itn, nt);
355 	return nt;
356 
357 err_dev_set_mtu:
358 	unregister_netdevice(dev);
359 	return ERR_PTR(err);
360 }
361 
362 void ip_tunnel_md_udp_encap(struct sk_buff *skb, struct ip_tunnel_info *info)
363 {
364 	const struct iphdr *iph = ip_hdr(skb);
365 	const struct udphdr *udph;
366 
367 	if (iph->protocol != IPPROTO_UDP)
368 		return;
369 
370 	udph = (struct udphdr *)((__u8 *)iph + (iph->ihl << 2));
371 	info->encap.sport = udph->source;
372 	info->encap.dport = udph->dest;
373 }
374 EXPORT_SYMBOL(ip_tunnel_md_udp_encap);
375 
376 int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
377 		  const struct tnl_ptk_info *tpi, struct metadata_dst *tun_dst,
378 		  bool log_ecn_error)
379 {
380 	const struct iphdr *iph = ip_hdr(skb);
381 	int nh, err;
382 
383 #ifdef CONFIG_NET_IPGRE_BROADCAST
384 	if (ipv4_is_multicast(iph->daddr)) {
385 		DEV_STATS_INC(tunnel->dev, multicast);
386 		skb->pkt_type = PACKET_BROADCAST;
387 	}
388 #endif
389 
390 	if (test_bit(IP_TUNNEL_CSUM_BIT, tunnel->parms.i_flags) !=
391 	    test_bit(IP_TUNNEL_CSUM_BIT, tpi->flags)) {
392 		DEV_STATS_INC(tunnel->dev, rx_crc_errors);
393 		DEV_STATS_INC(tunnel->dev, rx_errors);
394 		goto drop;
395 	}
396 
397 	if (test_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.i_flags)) {
398 		if (!test_bit(IP_TUNNEL_SEQ_BIT, tpi->flags) ||
399 		    (tunnel->i_seqno && (s32)(ntohl(tpi->seq) - tunnel->i_seqno) < 0)) {
400 			DEV_STATS_INC(tunnel->dev, rx_fifo_errors);
401 			DEV_STATS_INC(tunnel->dev, rx_errors);
402 			goto drop;
403 		}
404 		tunnel->i_seqno = ntohl(tpi->seq) + 1;
405 	}
406 
407 	/* Save offset of outer header relative to skb->head,
408 	 * because we are going to reset the network header to the inner header
409 	 * and might change skb->head.
410 	 */
411 	nh = skb_network_header(skb) - skb->head;
412 
413 	skb_set_network_header(skb, (tunnel->dev->type == ARPHRD_ETHER) ? ETH_HLEN : 0);
414 
415 	if (!pskb_inet_may_pull(skb)) {
416 		DEV_STATS_INC(tunnel->dev, rx_length_errors);
417 		DEV_STATS_INC(tunnel->dev, rx_errors);
418 		goto drop;
419 	}
420 	iph = (struct iphdr *)(skb->head + nh);
421 
422 	err = IP_ECN_decapsulate(iph, skb);
423 	if (unlikely(err)) {
424 		if (log_ecn_error)
425 			net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
426 					&iph->saddr, iph->tos);
427 		if (err > 1) {
428 			DEV_STATS_INC(tunnel->dev, rx_frame_errors);
429 			DEV_STATS_INC(tunnel->dev, rx_errors);
430 			goto drop;
431 		}
432 	}
433 
434 	dev_sw_netstats_rx_add(tunnel->dev, skb->len);
435 	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));
436 
437 	if (tunnel->dev->type == ARPHRD_ETHER) {
438 		skb->protocol = eth_type_trans(skb, tunnel->dev);
439 		skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
440 	} else {
441 		skb->dev = tunnel->dev;
442 	}
443 
444 	if (tun_dst)
445 		skb_dst_set(skb, (struct dst_entry *)tun_dst);
446 
447 	gro_cells_receive(&tunnel->gro_cells, skb);
448 	return 0;
449 
450 drop:
451 	if (tun_dst)
452 		dst_release((struct dst_entry *)tun_dst);
453 	kfree_skb(skb);
454 	return 0;
455 }
456 EXPORT_SYMBOL_GPL(ip_tunnel_rcv);
457 
458 int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *ops,
459 			    unsigned int num)
460 {
461 	if (num >= MAX_IPTUN_ENCAP_OPS)
462 		return -ERANGE;
463 
464 	return !cmpxchg((const struct ip_tunnel_encap_ops **)
465 			&iptun_encaps[num],
466 			NULL, ops) ? 0 : -1;
467 }
468 EXPORT_SYMBOL(ip_tunnel_encap_add_ops);
469 
470 int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *ops,
471 			    unsigned int num)
472 {
473 	int ret;
474 
475 	if (num >= MAX_IPTUN_ENCAP_OPS)
476 		return -ERANGE;
477 
478 	ret = (cmpxchg((const struct ip_tunnel_encap_ops **)
479 		       &iptun_encaps[num],
480 		       ops, NULL) == ops) ? 0 : -1;
481 
482 	synchronize_net();
483 
484 	return ret;
485 }
486 EXPORT_SYMBOL(ip_tunnel_encap_del_ops);
487 
488 int ip_tunnel_encap_setup(struct ip_tunnel *t,
489 			  struct ip_tunnel_encap *ipencap)
490 {
491 	int hlen;
492 
493 	memset(&t->encap, 0, sizeof(t->encap));
494 
495 	hlen = ip_encap_hlen(ipencap);
496 	if (hlen < 0)
497 		return hlen;
498 
499 	t->encap.type = ipencap->type;
500 	t->encap.sport = ipencap->sport;
501 	t->encap.dport = ipencap->dport;
502 	t->encap.flags = ipencap->flags;
503 
504 	t->encap_hlen = hlen;
505 	t->hlen = t->encap_hlen + t->tun_hlen;
506 
507 	return 0;
508 }
509 EXPORT_SYMBOL_GPL(ip_tunnel_encap_setup);
510 
511 static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
512 			    struct rtable *rt, __be16 df,
513 			    const struct iphdr *inner_iph,
514 			    int tunnel_hlen, __be32 dst, bool md)
515 {
516 	struct ip_tunnel *tunnel = netdev_priv(dev);
517 	int pkt_size;
518 	int mtu;
519 
520 	tunnel_hlen = md ? tunnel_hlen : tunnel->hlen;
521 	pkt_size = skb->len - tunnel_hlen;
522 	pkt_size -= dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0;
523 
524 	if (df) {
525 		mtu = dst_mtu(&rt->dst) - (sizeof(struct iphdr) + tunnel_hlen);
526 		mtu -= dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0;
527 	} else {
528 		mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
529 	}
530 
531 	if (skb_valid_dst(skb))
532 		skb_dst_update_pmtu_no_confirm(skb, mtu);
533 
534 	if (skb->protocol == htons(ETH_P_IP)) {
535 		if (!skb_is_gso(skb) &&
536 		    (inner_iph->frag_off & htons(IP_DF)) &&
537 		    mtu < pkt_size) {
538 			icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
539 			return -E2BIG;
540 		}
541 	}
542 #if IS_ENABLED(CONFIG_IPV6)
543 	else if (skb->protocol == htons(ETH_P_IPV6)) {
544 		struct rt6_info *rt6;
545 		__be32 daddr;
546 
547 		rt6 = skb_valid_dst(skb) ? dst_rt6_info(skb_dst(skb)) :
548 					   NULL;
549 		daddr = md ? dst : tunnel->parms.iph.daddr;
550 
551 		if (rt6 && mtu < dst_mtu(skb_dst(skb)) &&
552 			   mtu >= IPV6_MIN_MTU) {
553 			if ((daddr && !ipv4_is_multicast(daddr)) ||
554 			    rt6->rt6i_dst.plen == 128) {
555 				rt6->rt6i_flags |= RTF_MODIFIED;
556 				dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
557 			}
558 		}
559 
560 		if (!skb_is_gso(skb) && mtu >= IPV6_MIN_MTU &&
561 					mtu < pkt_size) {
562 			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
563 			return -E2BIG;
564 		}
565 	}
566 #endif
567 	return 0;
568 }
569 
570 static void ip_tunnel_adj_headroom(struct net_device *dev, unsigned int headroom)
571 {
572 	/* we must cap headroom to some upperlimit, else pskb_expand_head
573 	 * will overflow header offsets in skb_headers_offset_update().
574 	 */
575 	static const unsigned int max_allowed = 512;
576 
577 	if (headroom > max_allowed)
578 		headroom = max_allowed;
579 
580 	if (headroom > READ_ONCE(dev->needed_headroom))
581 		WRITE_ONCE(dev->needed_headroom, headroom);
582 }
583 
584 void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
585 		       u8 proto, int tunnel_hlen)
586 {
587 	struct ip_tunnel *tunnel = netdev_priv(dev);
588 	u32 headroom = sizeof(struct iphdr);
589 	struct ip_tunnel_info *tun_info;
590 	const struct ip_tunnel_key *key;
591 	const struct iphdr *inner_iph;
592 	struct rtable *rt = NULL;
593 	struct flowi4 fl4;
594 	__be16 df = 0;
595 	u8 tos, ttl;
596 	bool use_cache;
597 
598 	tun_info = skb_tunnel_info(skb);
599 	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
600 		     ip_tunnel_info_af(tun_info) != AF_INET))
601 		goto tx_error;
602 	key = &tun_info->key;
603 	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
604 	inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
605 	tos = key->tos;
606 	if (tos == 1) {
607 		if (skb->protocol == htons(ETH_P_IP))
608 			tos = inner_iph->tos;
609 		else if (skb->protocol == htons(ETH_P_IPV6))
610 			tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
611 	}
612 	ip_tunnel_init_flow(&fl4, proto, key->u.ipv4.dst, key->u.ipv4.src,
613 			    tunnel_id_to_key32(key->tun_id),
614 			    tos & INET_DSCP_MASK, dev_net(dev), 0, skb->mark,
615 			    skb_get_hash(skb), key->flow_flags);
616 
617 	if (!tunnel_hlen)
618 		tunnel_hlen = ip_encap_hlen(&tun_info->encap);
619 
620 	if (ip_tunnel_encap(skb, &tun_info->encap, &proto, &fl4) < 0)
621 		goto tx_error;
622 
623 	use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
624 	if (use_cache)
625 		rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl4.saddr);
626 	if (!rt) {
627 		rt = ip_route_output_key(tunnel->net, &fl4);
628 		if (IS_ERR(rt)) {
629 			DEV_STATS_INC(dev, tx_carrier_errors);
630 			goto tx_error;
631 		}
632 		if (use_cache)
633 			dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
634 					  fl4.saddr);
635 	}
636 	if (rt->dst.dev == dev) {
637 		ip_rt_put(rt);
638 		DEV_STATS_INC(dev, collisions);
639 		goto tx_error;
640 	}
641 
642 	if (test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, key->tun_flags))
643 		df = htons(IP_DF);
644 	if (tnl_update_pmtu(dev, skb, rt, df, inner_iph, tunnel_hlen,
645 			    key->u.ipv4.dst, true)) {
646 		ip_rt_put(rt);
647 		goto tx_error;
648 	}
649 
650 	tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
651 	ttl = key->ttl;
652 	if (ttl == 0) {
653 		if (skb->protocol == htons(ETH_P_IP))
654 			ttl = inner_iph->ttl;
655 		else if (skb->protocol == htons(ETH_P_IPV6))
656 			ttl = ((const struct ipv6hdr *)inner_iph)->hop_limit;
657 		else
658 			ttl = ip4_dst_hoplimit(&rt->dst);
659 	}
660 
661 	headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
662 	if (skb_cow_head(skb, headroom)) {
663 		ip_rt_put(rt);
664 		goto tx_dropped;
665 	}
666 
667 	ip_tunnel_adj_headroom(dev, headroom);
668 
669 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, proto, tos, ttl,
670 		      df, !net_eq(tunnel->net, dev_net(dev)));
671 	return;
672 tx_error:
673 	DEV_STATS_INC(dev, tx_errors);
674 	goto kfree;
675 tx_dropped:
676 	DEV_STATS_INC(dev, tx_dropped);
677 kfree:
678 	kfree_skb(skb);
679 }
680 EXPORT_SYMBOL_GPL(ip_md_tunnel_xmit);
681 
682 void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
683 		    const struct iphdr *tnl_params, u8 protocol)
684 {
685 	struct ip_tunnel *tunnel = netdev_priv(dev);
686 	struct ip_tunnel_info *tun_info = NULL;
687 	const struct iphdr *inner_iph;
688 	unsigned int max_headroom;	/* The extra header space needed */
689 	struct rtable *rt = NULL;		/* Route to the other host */
690 	__be16 payload_protocol;
691 	bool use_cache = false;
692 	struct flowi4 fl4;
693 	bool md = false;
694 	bool connected;
695 	u8 tos, ttl;
696 	__be32 dst;
697 	__be16 df;
698 
699 	inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
700 	connected = (tunnel->parms.iph.daddr != 0);
701 	payload_protocol = skb_protocol(skb, true);
702 
703 	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
704 
705 	dst = tnl_params->daddr;
706 	if (dst == 0) {
707 		/* NBMA tunnel */
708 
709 		if (!skb_dst(skb)) {
710 			DEV_STATS_INC(dev, tx_fifo_errors);
711 			goto tx_error;
712 		}
713 
714 		tun_info = skb_tunnel_info(skb);
715 		if (tun_info && (tun_info->mode & IP_TUNNEL_INFO_TX) &&
716 		    ip_tunnel_info_af(tun_info) == AF_INET &&
717 		    tun_info->key.u.ipv4.dst) {
718 			dst = tun_info->key.u.ipv4.dst;
719 			md = true;
720 			connected = true;
721 		} else if (payload_protocol == htons(ETH_P_IP)) {
722 			rt = skb_rtable(skb);
723 			dst = rt_nexthop(rt, inner_iph->daddr);
724 		}
725 #if IS_ENABLED(CONFIG_IPV6)
726 		else if (payload_protocol == htons(ETH_P_IPV6)) {
727 			const struct in6_addr *addr6;
728 			struct neighbour *neigh;
729 			bool do_tx_error_icmp;
730 			int addr_type;
731 
732 			neigh = dst_neigh_lookup(skb_dst(skb),
733 						 &ipv6_hdr(skb)->daddr);
734 			if (!neigh)
735 				goto tx_error;
736 
737 			addr6 = (const struct in6_addr *)&neigh->primary_key;
738 			addr_type = ipv6_addr_type(addr6);
739 
740 			if (addr_type == IPV6_ADDR_ANY) {
741 				addr6 = &ipv6_hdr(skb)->daddr;
742 				addr_type = ipv6_addr_type(addr6);
743 			}
744 
745 			if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
746 				do_tx_error_icmp = true;
747 			else {
748 				do_tx_error_icmp = false;
749 				dst = addr6->s6_addr32[3];
750 			}
751 			neigh_release(neigh);
752 			if (do_tx_error_icmp)
753 				goto tx_error_icmp;
754 		}
755 #endif
756 		else
757 			goto tx_error;
758 
759 		if (!md)
760 			connected = false;
761 	}
762 
763 	tos = tnl_params->tos;
764 	if (tos & 0x1) {
765 		tos &= ~0x1;
766 		if (payload_protocol == htons(ETH_P_IP)) {
767 			tos = inner_iph->tos;
768 			connected = false;
769 		} else if (payload_protocol == htons(ETH_P_IPV6)) {
770 			tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
771 			connected = false;
772 		}
773 	}
774 
775 	ip_tunnel_init_flow(&fl4, protocol, dst, tnl_params->saddr,
776 			    tunnel->parms.o_key, tos & INET_DSCP_MASK,
777 			    dev_net(dev), READ_ONCE(tunnel->parms.link),
778 			    tunnel->fwmark, skb_get_hash(skb), 0);
779 
780 	if (ip_tunnel_encap(skb, &tunnel->encap, &protocol, &fl4) < 0)
781 		goto tx_error;
782 
783 	if (connected && md) {
784 		use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
785 		if (use_cache)
786 			rt = dst_cache_get_ip4(&tun_info->dst_cache,
787 					       &fl4.saddr);
788 	} else {
789 		rt = connected ? dst_cache_get_ip4(&tunnel->dst_cache,
790 						&fl4.saddr) : NULL;
791 	}
792 
793 	if (!rt) {
794 		rt = ip_route_output_key(tunnel->net, &fl4);
795 
796 		if (IS_ERR(rt)) {
797 			DEV_STATS_INC(dev, tx_carrier_errors);
798 			goto tx_error;
799 		}
800 		if (use_cache)
801 			dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
802 					  fl4.saddr);
803 		else if (!md && connected)
804 			dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst,
805 					  fl4.saddr);
806 	}
807 
808 	if (rt->dst.dev == dev) {
809 		ip_rt_put(rt);
810 		DEV_STATS_INC(dev, collisions);
811 		goto tx_error;
812 	}
813 
814 	df = tnl_params->frag_off;
815 	if (payload_protocol == htons(ETH_P_IP) && !tunnel->ignore_df)
816 		df |= (inner_iph->frag_off & htons(IP_DF));
817 
818 	if (tnl_update_pmtu(dev, skb, rt, df, inner_iph, 0, 0, false)) {
819 		ip_rt_put(rt);
820 		goto tx_error;
821 	}
822 
823 	if (tunnel->err_count > 0) {
824 		if (time_before(jiffies,
825 				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
826 			tunnel->err_count--;
827 
828 			dst_link_failure(skb);
829 		} else
830 			tunnel->err_count = 0;
831 	}
832 
833 	tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
834 	ttl = tnl_params->ttl;
835 	if (ttl == 0) {
836 		if (payload_protocol == htons(ETH_P_IP))
837 			ttl = inner_iph->ttl;
838 #if IS_ENABLED(CONFIG_IPV6)
839 		else if (payload_protocol == htons(ETH_P_IPV6))
840 			ttl = ((const struct ipv6hdr *)inner_iph)->hop_limit;
841 #endif
842 		else
843 			ttl = ip4_dst_hoplimit(&rt->dst);
844 	}
845 
846 	max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
847 			+ rt->dst.header_len + ip_encap_hlen(&tunnel->encap);
848 
849 	if (skb_cow_head(skb, max_headroom)) {
850 		ip_rt_put(rt);
851 		DEV_STATS_INC(dev, tx_dropped);
852 		kfree_skb(skb);
853 		return;
854 	}
855 
856 	ip_tunnel_adj_headroom(dev, max_headroom);
857 
858 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
859 		      df, !net_eq(tunnel->net, dev_net(dev)));
860 	return;
861 
862 #if IS_ENABLED(CONFIG_IPV6)
863 tx_error_icmp:
864 	dst_link_failure(skb);
865 #endif
866 tx_error:
867 	DEV_STATS_INC(dev, tx_errors);
868 	kfree_skb(skb);
869 }
870 EXPORT_SYMBOL_GPL(ip_tunnel_xmit);
871 
872 static void ip_tunnel_update(struct ip_tunnel_net *itn,
873 			     struct ip_tunnel *t,
874 			     struct net_device *dev,
875 			     struct ip_tunnel_parm_kern *p,
876 			     bool set_mtu,
877 			     __u32 fwmark)
878 {
879 	ip_tunnel_del(itn, t);
880 	t->parms.iph.saddr = p->iph.saddr;
881 	t->parms.iph.daddr = p->iph.daddr;
882 	t->parms.i_key = p->i_key;
883 	t->parms.o_key = p->o_key;
884 	if (dev->type != ARPHRD_ETHER) {
885 		__dev_addr_set(dev, &p->iph.saddr, 4);
886 		memcpy(dev->broadcast, &p->iph.daddr, 4);
887 	}
888 	ip_tunnel_add(itn, t);
889 
890 	t->parms.iph.ttl = p->iph.ttl;
891 	t->parms.iph.tos = p->iph.tos;
892 	t->parms.iph.frag_off = p->iph.frag_off;
893 
894 	if (t->parms.link != p->link || t->fwmark != fwmark) {
895 		int mtu;
896 
897 		WRITE_ONCE(t->parms.link, p->link);
898 		t->fwmark = fwmark;
899 		mtu = ip_tunnel_bind_dev(dev);
900 		if (set_mtu)
901 			WRITE_ONCE(dev->mtu, mtu);
902 	}
903 	dst_cache_reset(&t->dst_cache);
904 	netdev_state_change(dev);
905 }
906 
907 int ip_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm_kern *p,
908 		  int cmd)
909 {
910 	int err = 0;
911 	struct ip_tunnel *t = netdev_priv(dev);
912 	struct net *net = t->net;
913 	struct ip_tunnel_net *itn = net_generic(net, t->ip_tnl_net_id);
914 
915 	switch (cmd) {
916 	case SIOCGETTUNNEL:
917 		if (dev == itn->fb_tunnel_dev) {
918 			t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
919 			if (!t)
920 				t = netdev_priv(dev);
921 		}
922 		memcpy(p, &t->parms, sizeof(*p));
923 		break;
924 
925 	case SIOCADDTUNNEL:
926 	case SIOCCHGTUNNEL:
927 		err = -EPERM;
928 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
929 			goto done;
930 		if (p->iph.ttl)
931 			p->iph.frag_off |= htons(IP_DF);
932 		if (!test_bit(IP_TUNNEL_VTI_BIT, p->i_flags)) {
933 			if (!test_bit(IP_TUNNEL_KEY_BIT, p->i_flags))
934 				p->i_key = 0;
935 			if (!test_bit(IP_TUNNEL_KEY_BIT, p->o_flags))
936 				p->o_key = 0;
937 		}
938 
939 		t = ip_tunnel_find(itn, p, itn->type);
940 
941 		if (cmd == SIOCADDTUNNEL) {
942 			if (!t) {
943 				t = ip_tunnel_create(net, itn, p);
944 				err = PTR_ERR_OR_ZERO(t);
945 				break;
946 			}
947 
948 			err = -EEXIST;
949 			break;
950 		}
951 		if (dev != itn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
952 			if (t) {
953 				if (t->dev != dev) {
954 					err = -EEXIST;
955 					break;
956 				}
957 			} else {
958 				unsigned int nflags = 0;
959 
960 				if (ipv4_is_multicast(p->iph.daddr))
961 					nflags = IFF_BROADCAST;
962 				else if (p->iph.daddr)
963 					nflags = IFF_POINTOPOINT;
964 
965 				if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
966 					err = -EINVAL;
967 					break;
968 				}
969 
970 				t = netdev_priv(dev);
971 			}
972 		}
973 
974 		if (t) {
975 			err = 0;
976 			ip_tunnel_update(itn, t, dev, p, true, 0);
977 		} else {
978 			err = -ENOENT;
979 		}
980 		break;
981 
982 	case SIOCDELTUNNEL:
983 		err = -EPERM;
984 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
985 			goto done;
986 
987 		if (dev == itn->fb_tunnel_dev) {
988 			err = -ENOENT;
989 			t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
990 			if (!t)
991 				goto done;
992 			err = -EPERM;
993 			if (t == netdev_priv(itn->fb_tunnel_dev))
994 				goto done;
995 			dev = t->dev;
996 		}
997 		unregister_netdevice(dev);
998 		err = 0;
999 		break;
1000 
1001 	default:
1002 		err = -EINVAL;
1003 	}
1004 
1005 done:
1006 	return err;
1007 }
1008 EXPORT_SYMBOL_GPL(ip_tunnel_ctl);
1009 
1010 bool ip_tunnel_parm_from_user(struct ip_tunnel_parm_kern *kp,
1011 			      const void __user *data)
1012 {
1013 	struct ip_tunnel_parm p;
1014 
1015 	if (copy_from_user(&p, data, sizeof(p)))
1016 		return false;
1017 
1018 	strscpy(kp->name, p.name);
1019 	kp->link = p.link;
1020 	ip_tunnel_flags_from_be16(kp->i_flags, p.i_flags);
1021 	ip_tunnel_flags_from_be16(kp->o_flags, p.o_flags);
1022 	kp->i_key = p.i_key;
1023 	kp->o_key = p.o_key;
1024 	memcpy(&kp->iph, &p.iph, min(sizeof(kp->iph), sizeof(p.iph)));
1025 
1026 	return true;
1027 }
1028 EXPORT_SYMBOL_GPL(ip_tunnel_parm_from_user);
1029 
1030 bool ip_tunnel_parm_to_user(void __user *data, struct ip_tunnel_parm_kern *kp)
1031 {
1032 	struct ip_tunnel_parm p;
1033 
1034 	if (!ip_tunnel_flags_is_be16_compat(kp->i_flags) ||
1035 	    !ip_tunnel_flags_is_be16_compat(kp->o_flags))
1036 		return false;
1037 
1038 	memset(&p, 0, sizeof(p));
1039 
1040 	strscpy(p.name, kp->name);
1041 	p.link = kp->link;
1042 	p.i_flags = ip_tunnel_flags_to_be16(kp->i_flags);
1043 	p.o_flags = ip_tunnel_flags_to_be16(kp->o_flags);
1044 	p.i_key = kp->i_key;
1045 	p.o_key = kp->o_key;
1046 	memcpy(&p.iph, &kp->iph, min(sizeof(p.iph), sizeof(kp->iph)));
1047 
1048 	return !copy_to_user(data, &p, sizeof(p));
1049 }
1050 EXPORT_SYMBOL_GPL(ip_tunnel_parm_to_user);
1051 
1052 int ip_tunnel_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1053 			     void __user *data, int cmd)
1054 {
1055 	struct ip_tunnel_parm_kern p;
1056 	int err;
1057 
1058 	if (!ip_tunnel_parm_from_user(&p, data))
1059 		return -EFAULT;
1060 	err = dev->netdev_ops->ndo_tunnel_ctl(dev, &p, cmd);
1061 	if (!err && !ip_tunnel_parm_to_user(data, &p))
1062 		return -EFAULT;
1063 	return err;
1064 }
1065 EXPORT_SYMBOL_GPL(ip_tunnel_siocdevprivate);
1066 
1067 int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict)
1068 {
1069 	struct ip_tunnel *tunnel = netdev_priv(dev);
1070 	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1071 	int max_mtu = IP_MAX_MTU - t_hlen;
1072 
1073 	if (dev->type == ARPHRD_ETHER)
1074 		max_mtu -= dev->hard_header_len;
1075 
1076 	if (new_mtu < ETH_MIN_MTU)
1077 		return -EINVAL;
1078 
1079 	if (new_mtu > max_mtu) {
1080 		if (strict)
1081 			return -EINVAL;
1082 
1083 		new_mtu = max_mtu;
1084 	}
1085 
1086 	WRITE_ONCE(dev->mtu, new_mtu);
1087 	return 0;
1088 }
1089 EXPORT_SYMBOL_GPL(__ip_tunnel_change_mtu);
1090 
1091 int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1092 {
1093 	return __ip_tunnel_change_mtu(dev, new_mtu, true);
1094 }
1095 EXPORT_SYMBOL_GPL(ip_tunnel_change_mtu);
1096 
1097 static void ip_tunnel_dev_free(struct net_device *dev)
1098 {
1099 	struct ip_tunnel *tunnel = netdev_priv(dev);
1100 
1101 	gro_cells_destroy(&tunnel->gro_cells);
1102 	dst_cache_destroy(&tunnel->dst_cache);
1103 }
1104 
1105 void ip_tunnel_dellink(struct net_device *dev, struct list_head *head)
1106 {
1107 	struct ip_tunnel *tunnel = netdev_priv(dev);
1108 	struct ip_tunnel_net *itn;
1109 
1110 	itn = net_generic(tunnel->net, tunnel->ip_tnl_net_id);
1111 
1112 	if (itn->fb_tunnel_dev != dev) {
1113 		ip_tunnel_del(itn, netdev_priv(dev));
1114 		unregister_netdevice_queue(dev, head);
1115 	}
1116 }
1117 EXPORT_SYMBOL_GPL(ip_tunnel_dellink);
1118 
1119 struct net *ip_tunnel_get_link_net(const struct net_device *dev)
1120 {
1121 	struct ip_tunnel *tunnel = netdev_priv(dev);
1122 
1123 	return READ_ONCE(tunnel->net);
1124 }
1125 EXPORT_SYMBOL(ip_tunnel_get_link_net);
1126 
1127 int ip_tunnel_get_iflink(const struct net_device *dev)
1128 {
1129 	const struct ip_tunnel *tunnel = netdev_priv(dev);
1130 
1131 	return READ_ONCE(tunnel->parms.link);
1132 }
1133 EXPORT_SYMBOL(ip_tunnel_get_iflink);
1134 
1135 int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
1136 				  struct rtnl_link_ops *ops, char *devname)
1137 {
1138 	struct ip_tunnel_net *itn = net_generic(net, ip_tnl_net_id);
1139 	struct ip_tunnel_parm_kern parms;
1140 	unsigned int i;
1141 
1142 	itn->rtnl_link_ops = ops;
1143 	for (i = 0; i < IP_TNL_HASH_SIZE; i++)
1144 		INIT_HLIST_HEAD(&itn->tunnels[i]);
1145 
1146 	if (!ops || !net_has_fallback_tunnels(net)) {
1147 		struct ip_tunnel_net *it_init_net;
1148 
1149 		it_init_net = net_generic(&init_net, ip_tnl_net_id);
1150 		itn->type = it_init_net->type;
1151 		itn->fb_tunnel_dev = NULL;
1152 		return 0;
1153 	}
1154 
1155 	memset(&parms, 0, sizeof(parms));
1156 	if (devname)
1157 		strscpy(parms.name, devname, IFNAMSIZ);
1158 
1159 	rtnl_lock();
1160 	itn->fb_tunnel_dev = __ip_tunnel_create(net, ops, &parms);
1161 	/* FB netdevice is special: we have one, and only one per netns.
1162 	 * Allowing to move it to another netns is clearly unsafe.
1163 	 */
1164 	if (!IS_ERR(itn->fb_tunnel_dev)) {
1165 		itn->fb_tunnel_dev->netns_local = true;
1166 		itn->fb_tunnel_dev->mtu = ip_tunnel_bind_dev(itn->fb_tunnel_dev);
1167 		ip_tunnel_add(itn, netdev_priv(itn->fb_tunnel_dev));
1168 		itn->type = itn->fb_tunnel_dev->type;
1169 	}
1170 	rtnl_unlock();
1171 
1172 	return PTR_ERR_OR_ZERO(itn->fb_tunnel_dev);
1173 }
1174 EXPORT_SYMBOL_GPL(ip_tunnel_init_net);
1175 
1176 static void ip_tunnel_destroy(struct net *net, struct ip_tunnel_net *itn,
1177 			      struct list_head *head,
1178 			      struct rtnl_link_ops *ops)
1179 {
1180 	struct net_device *dev, *aux;
1181 	int h;
1182 
1183 	for_each_netdev_safe(net, dev, aux)
1184 		if (dev->rtnl_link_ops == ops)
1185 			unregister_netdevice_queue(dev, head);
1186 
1187 	for (h = 0; h < IP_TNL_HASH_SIZE; h++) {
1188 		struct ip_tunnel *t;
1189 		struct hlist_node *n;
1190 		struct hlist_head *thead = &itn->tunnels[h];
1191 
1192 		hlist_for_each_entry_safe(t, n, thead, hash_node)
1193 			/* If dev is in the same netns, it has already
1194 			 * been added to the list by the previous loop.
1195 			 */
1196 			if (!net_eq(dev_net(t->dev), net))
1197 				unregister_netdevice_queue(t->dev, head);
1198 	}
1199 }
1200 
1201 void ip_tunnel_delete_nets(struct list_head *net_list, unsigned int id,
1202 			   struct rtnl_link_ops *ops,
1203 			   struct list_head *dev_to_kill)
1204 {
1205 	struct ip_tunnel_net *itn;
1206 	struct net *net;
1207 
1208 	ASSERT_RTNL();
1209 	list_for_each_entry(net, net_list, exit_list) {
1210 		itn = net_generic(net, id);
1211 		ip_tunnel_destroy(net, itn, dev_to_kill, ops);
1212 	}
1213 }
1214 EXPORT_SYMBOL_GPL(ip_tunnel_delete_nets);
1215 
1216 int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
1217 		      struct ip_tunnel_parm_kern *p, __u32 fwmark)
1218 {
1219 	struct ip_tunnel *nt;
1220 	struct net *net = dev_net(dev);
1221 	struct ip_tunnel_net *itn;
1222 	int mtu;
1223 	int err;
1224 
1225 	nt = netdev_priv(dev);
1226 	itn = net_generic(net, nt->ip_tnl_net_id);
1227 
1228 	if (nt->collect_md) {
1229 		if (rtnl_dereference(itn->collect_md_tun))
1230 			return -EEXIST;
1231 	} else {
1232 		if (ip_tunnel_find(itn, p, dev->type))
1233 			return -EEXIST;
1234 	}
1235 
1236 	nt->net = net;
1237 	nt->parms = *p;
1238 	nt->fwmark = fwmark;
1239 	err = register_netdevice(dev);
1240 	if (err)
1241 		goto err_register_netdevice;
1242 
1243 	if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
1244 		eth_hw_addr_random(dev);
1245 
1246 	mtu = ip_tunnel_bind_dev(dev);
1247 	if (tb[IFLA_MTU]) {
1248 		unsigned int max = IP_MAX_MTU - (nt->hlen + sizeof(struct iphdr));
1249 
1250 		if (dev->type == ARPHRD_ETHER)
1251 			max -= dev->hard_header_len;
1252 
1253 		mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU, max);
1254 	}
1255 
1256 	err = dev_set_mtu(dev, mtu);
1257 	if (err)
1258 		goto err_dev_set_mtu;
1259 
1260 	ip_tunnel_add(itn, nt);
1261 	return 0;
1262 
1263 err_dev_set_mtu:
1264 	unregister_netdevice(dev);
1265 err_register_netdevice:
1266 	return err;
1267 }
1268 EXPORT_SYMBOL_GPL(ip_tunnel_newlink);
1269 
1270 int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
1271 			 struct ip_tunnel_parm_kern *p, __u32 fwmark)
1272 {
1273 	struct ip_tunnel *t;
1274 	struct ip_tunnel *tunnel = netdev_priv(dev);
1275 	struct net *net = tunnel->net;
1276 	struct ip_tunnel_net *itn = net_generic(net, tunnel->ip_tnl_net_id);
1277 
1278 	if (dev == itn->fb_tunnel_dev)
1279 		return -EINVAL;
1280 
1281 	t = ip_tunnel_find(itn, p, dev->type);
1282 
1283 	if (t) {
1284 		if (t->dev != dev)
1285 			return -EEXIST;
1286 	} else {
1287 		t = tunnel;
1288 
1289 		if (dev->type != ARPHRD_ETHER) {
1290 			unsigned int nflags = 0;
1291 
1292 			if (ipv4_is_multicast(p->iph.daddr))
1293 				nflags = IFF_BROADCAST;
1294 			else if (p->iph.daddr)
1295 				nflags = IFF_POINTOPOINT;
1296 
1297 			if ((dev->flags ^ nflags) &
1298 			    (IFF_POINTOPOINT | IFF_BROADCAST))
1299 				return -EINVAL;
1300 		}
1301 	}
1302 
1303 	ip_tunnel_update(itn, t, dev, p, !tb[IFLA_MTU], fwmark);
1304 	return 0;
1305 }
1306 EXPORT_SYMBOL_GPL(ip_tunnel_changelink);
1307 
1308 int ip_tunnel_init(struct net_device *dev)
1309 {
1310 	struct ip_tunnel *tunnel = netdev_priv(dev);
1311 	struct iphdr *iph = &tunnel->parms.iph;
1312 	int err;
1313 
1314 	dev->needs_free_netdev = true;
1315 	dev->priv_destructor = ip_tunnel_dev_free;
1316 	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1317 
1318 	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1319 	if (err)
1320 		return err;
1321 
1322 	err = gro_cells_init(&tunnel->gro_cells, dev);
1323 	if (err) {
1324 		dst_cache_destroy(&tunnel->dst_cache);
1325 		return err;
1326 	}
1327 
1328 	tunnel->dev = dev;
1329 	tunnel->net = dev_net(dev);
1330 	strscpy(tunnel->parms.name, dev->name);
1331 	iph->version		= 4;
1332 	iph->ihl		= 5;
1333 
1334 	if (tunnel->collect_md)
1335 		netif_keep_dst(dev);
1336 	netdev_lockdep_set_classes(dev);
1337 	return 0;
1338 }
1339 EXPORT_SYMBOL_GPL(ip_tunnel_init);
1340 
1341 void ip_tunnel_uninit(struct net_device *dev)
1342 {
1343 	struct ip_tunnel *tunnel = netdev_priv(dev);
1344 	struct net *net = tunnel->net;
1345 	struct ip_tunnel_net *itn;
1346 
1347 	itn = net_generic(net, tunnel->ip_tnl_net_id);
1348 	ip_tunnel_del(itn, netdev_priv(dev));
1349 	if (itn->fb_tunnel_dev == dev)
1350 		WRITE_ONCE(itn->fb_tunnel_dev, NULL);
1351 
1352 	dst_cache_reset(&tunnel->dst_cache);
1353 }
1354 EXPORT_SYMBOL_GPL(ip_tunnel_uninit);
1355 
1356 /* Do least required initialization, rest of init is done in tunnel_init call */
1357 void ip_tunnel_setup(struct net_device *dev, unsigned int net_id)
1358 {
1359 	struct ip_tunnel *tunnel = netdev_priv(dev);
1360 	tunnel->ip_tnl_net_id = net_id;
1361 }
1362 EXPORT_SYMBOL_GPL(ip_tunnel_setup);
1363 
1364 MODULE_DESCRIPTION("IPv4 tunnel implementation library");
1365 MODULE_LICENSE("GPL");
1366