1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_IP_TUNNELS_H
3 #define __NET_IP_TUNNELS_H 1
4 
5 #include <linux/if_tunnel.h>
6 #include <linux/netdevice.h>
7 #include <linux/skbuff.h>
8 #include <linux/socket.h>
9 #include <linux/types.h>
10 #include <linux/u64_stats_sync.h>
11 #include <linux/bitops.h>
12 
13 #include <net/dsfield.h>
14 #include <net/gro_cells.h>
15 #include <net/inet_ecn.h>
16 #include <net/netns/generic.h>
17 #include <net/rtnetlink.h>
18 #include <net/lwtunnel.h>
19 #include <net/dst_cache.h>
20 
21 #if IS_ENABLED(CONFIG_IPV6)
22 #include <net/ipv6.h>
23 #include <net/ip6_fib.h>
24 #include <net/ip6_route.h>
25 #endif
26 
27 /* Keep error state on tunnel for 30 sec */
28 #define IPTUNNEL_ERR_TIMEO	(30*HZ)
29 
30 /* Used to memset ip_tunnel padding. */
31 #define IP_TUNNEL_KEY_SIZE	offsetofend(struct ip_tunnel_key, tp_dst)
32 
33 /* Used to memset ipv4 address padding. */
34 #define IP_TUNNEL_KEY_IPV4_PAD	offsetofend(struct ip_tunnel_key, u.ipv4.dst)
35 #define IP_TUNNEL_KEY_IPV4_PAD_LEN				\
36 	(sizeof_field(struct ip_tunnel_key, u) -		\
37 	 sizeof_field(struct ip_tunnel_key, u.ipv4))
38 
39 struct ip_tunnel_key {
40 	__be64			tun_id;
41 	union {
42 		struct {
43 			__be32	src;
44 			__be32	dst;
45 		} ipv4;
46 		struct {
47 			struct in6_addr src;
48 			struct in6_addr dst;
49 		} ipv6;
50 	} u;
51 	__be16			tun_flags;
52 	u8			tos;		/* TOS for IPv4, TC for IPv6 */
53 	u8			ttl;		/* TTL for IPv4, HL for IPv6 */
54 	__be32			label;		/* Flow Label for IPv6 */
55 	__be16			tp_src;
56 	__be16			tp_dst;
57 	__u8			flow_flags;
58 };
59 
60 /* Flags for ip_tunnel_info mode. */
61 #define IP_TUNNEL_INFO_TX	0x01	/* represents tx tunnel parameters */
62 #define IP_TUNNEL_INFO_IPV6	0x02	/* key contains IPv6 addresses */
63 #define IP_TUNNEL_INFO_BRIDGE	0x04	/* represents a bridged tunnel id */
64 
65 /* Maximum tunnel options length. */
66 #define IP_TUNNEL_OPTS_MAX					\
67 	GENMASK((sizeof_field(struct ip_tunnel_info,		\
68 			      options_len) * BITS_PER_BYTE) - 1, 0)
69 
70 struct ip_tunnel_info {
71 	struct ip_tunnel_key	key;
72 #ifdef CONFIG_DST_CACHE
73 	struct dst_cache	dst_cache;
74 #endif
75 	u8			options_len;
76 	u8			mode;
77 };
78 
79 /* 6rd prefix/relay information */
80 #ifdef CONFIG_IPV6_SIT_6RD
81 struct ip_tunnel_6rd_parm {
82 	struct in6_addr		prefix;
83 	__be32			relay_prefix;
84 	u16			prefixlen;
85 	u16			relay_prefixlen;
86 };
87 #endif
88 
89 struct ip_tunnel_encap {
90 	u16			type;
91 	u16			flags;
92 	__be16			sport;
93 	__be16			dport;
94 };
95 
96 struct ip_tunnel_prl_entry {
97 	struct ip_tunnel_prl_entry __rcu *next;
98 	__be32				addr;
99 	u16				flags;
100 	struct rcu_head			rcu_head;
101 };
102 
103 struct metadata_dst;
104 
105 struct ip_tunnel {
106 	struct ip_tunnel __rcu	*next;
107 	struct hlist_node hash_node;
108 
109 	struct net_device	*dev;
110 	netdevice_tracker	dev_tracker;
111 
112 	struct net		*net;	/* netns for packet i/o */
113 
114 	unsigned long	err_time;	/* Time when the last ICMP error
115 					 * arrived */
116 	int		err_count;	/* Number of arrived ICMP errors */
117 
118 	/* These four fields used only by GRE */
119 	u32		i_seqno;	/* The last seen seqno	*/
120 	atomic_t	o_seqno;	/* The last output seqno */
121 	int		tun_hlen;	/* Precalculated header length */
122 
123 	/* These four fields used only by ERSPAN */
124 	u32		index;		/* ERSPAN type II index */
125 	u8		erspan_ver;	/* ERSPAN version */
126 	u8		dir;		/* ERSPAN direction */
127 	u16		hwid;		/* ERSPAN hardware ID */
128 
129 	struct dst_cache dst_cache;
130 
131 	struct ip_tunnel_parm parms;
132 
133 	int		mlink;
134 	int		encap_hlen;	/* Encap header length (FOU,GUE) */
135 	int		hlen;		/* tun_hlen + encap_hlen */
136 	struct ip_tunnel_encap encap;
137 
138 	/* for SIT */
139 #ifdef CONFIG_IPV6_SIT_6RD
140 	struct ip_tunnel_6rd_parm ip6rd;
141 #endif
142 	struct ip_tunnel_prl_entry __rcu *prl;	/* potential router list */
143 	unsigned int		prl_count;	/* # of entries in PRL */
144 	unsigned int		ip_tnl_net_id;
145 	struct gro_cells	gro_cells;
146 	__u32			fwmark;
147 	bool			collect_md;
148 	bool			ignore_df;
149 };
150 
151 struct tnl_ptk_info {
152 	__be16 flags;
153 	__be16 proto;
154 	__be32 key;
155 	__be32 seq;
156 	int hdr_len;
157 };
158 
159 #define PACKET_RCVD	0
160 #define PACKET_REJECT	1
161 #define PACKET_NEXT	2
162 
163 #define IP_TNL_HASH_BITS   7
164 #define IP_TNL_HASH_SIZE   (1 << IP_TNL_HASH_BITS)
165 
166 struct ip_tunnel_net {
167 	struct net_device *fb_tunnel_dev;
168 	struct rtnl_link_ops *rtnl_link_ops;
169 	struct hlist_head tunnels[IP_TNL_HASH_SIZE];
170 	struct ip_tunnel __rcu *collect_md_tun;
171 	int type;
172 };
173 
ip_tunnel_key_init(struct ip_tunnel_key * key,__be32 saddr,__be32 daddr,u8 tos,u8 ttl,__be32 label,__be16 tp_src,__be16 tp_dst,__be64 tun_id,__be16 tun_flags)174 static inline void ip_tunnel_key_init(struct ip_tunnel_key *key,
175 				      __be32 saddr, __be32 daddr,
176 				      u8 tos, u8 ttl, __be32 label,
177 				      __be16 tp_src, __be16 tp_dst,
178 				      __be64 tun_id, __be16 tun_flags)
179 {
180 	key->tun_id = tun_id;
181 	key->u.ipv4.src = saddr;
182 	key->u.ipv4.dst = daddr;
183 	memset((unsigned char *)key + IP_TUNNEL_KEY_IPV4_PAD,
184 	       0, IP_TUNNEL_KEY_IPV4_PAD_LEN);
185 	key->tos = tos;
186 	key->ttl = ttl;
187 	key->label = label;
188 	key->tun_flags = tun_flags;
189 
190 	/* For the tunnel types on the top of IPsec, the tp_src and tp_dst of
191 	 * the upper tunnel are used.
192 	 * E.g: GRE over IPSEC, the tp_src and tp_port are zero.
193 	 */
194 	key->tp_src = tp_src;
195 	key->tp_dst = tp_dst;
196 
197 	/* Clear struct padding. */
198 	if (sizeof(*key) != IP_TUNNEL_KEY_SIZE)
199 		memset((unsigned char *)key + IP_TUNNEL_KEY_SIZE,
200 		       0, sizeof(*key) - IP_TUNNEL_KEY_SIZE);
201 }
202 
203 static inline bool
ip_tunnel_dst_cache_usable(const struct sk_buff * skb,const struct ip_tunnel_info * info)204 ip_tunnel_dst_cache_usable(const struct sk_buff *skb,
205 			   const struct ip_tunnel_info *info)
206 {
207 	if (skb->mark)
208 		return false;
209 	if (!info)
210 		return true;
211 	if (info->key.tun_flags & TUNNEL_NOCACHE)
212 		return false;
213 
214 	return true;
215 }
216 
ip_tunnel_info_af(const struct ip_tunnel_info * tun_info)217 static inline unsigned short ip_tunnel_info_af(const struct ip_tunnel_info
218 					       *tun_info)
219 {
220 	return tun_info->mode & IP_TUNNEL_INFO_IPV6 ? AF_INET6 : AF_INET;
221 }
222 
key32_to_tunnel_id(__be32 key)223 static inline __be64 key32_to_tunnel_id(__be32 key)
224 {
225 #ifdef __BIG_ENDIAN
226 	return (__force __be64)key;
227 #else
228 	return (__force __be64)((__force u64)key << 32);
229 #endif
230 }
231 
232 /* Returns the least-significant 32 bits of a __be64. */
tunnel_id_to_key32(__be64 tun_id)233 static inline __be32 tunnel_id_to_key32(__be64 tun_id)
234 {
235 #ifdef __BIG_ENDIAN
236 	return (__force __be32)tun_id;
237 #else
238 	return (__force __be32)((__force u64)tun_id >> 32);
239 #endif
240 }
241 
242 #ifdef CONFIG_INET
243 
ip_tunnel_init_flow(struct flowi4 * fl4,int proto,__be32 daddr,__be32 saddr,__be32 key,__u8 tos,struct net * net,int oif,__u32 mark,__u32 tun_inner_hash,__u8 flow_flags)244 static inline void ip_tunnel_init_flow(struct flowi4 *fl4,
245 				       int proto,
246 				       __be32 daddr, __be32 saddr,
247 				       __be32 key, __u8 tos,
248 				       struct net *net, int oif,
249 				       __u32 mark, __u32 tun_inner_hash,
250 				       __u8 flow_flags)
251 {
252 	memset(fl4, 0, sizeof(*fl4));
253 
254 	if (oif) {
255 		fl4->flowi4_l3mdev = l3mdev_master_upper_ifindex_by_index_rcu(net, oif);
256 		/* Legacy VRF/l3mdev use case */
257 		fl4->flowi4_oif = fl4->flowi4_l3mdev ? 0 : oif;
258 	}
259 
260 	fl4->daddr = daddr;
261 	fl4->saddr = saddr;
262 	fl4->flowi4_tos = tos;
263 	fl4->flowi4_proto = proto;
264 	fl4->fl4_gre_key = key;
265 	fl4->flowi4_mark = mark;
266 	fl4->flowi4_multipath_hash = tun_inner_hash;
267 	fl4->flowi4_flags = flow_flags;
268 }
269 
270 int ip_tunnel_init(struct net_device *dev);
271 void ip_tunnel_uninit(struct net_device *dev);
272 void  ip_tunnel_dellink(struct net_device *dev, struct list_head *head);
273 struct net *ip_tunnel_get_link_net(const struct net_device *dev);
274 int ip_tunnel_get_iflink(const struct net_device *dev);
275 int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
276 		       struct rtnl_link_ops *ops, char *devname);
277 
278 void ip_tunnel_delete_nets(struct list_head *list_net, unsigned int id,
279 			   struct rtnl_link_ops *ops);
280 
281 void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
282 		    const struct iphdr *tnl_params, const u8 protocol);
283 void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
284 		       const u8 proto, int tunnel_hlen);
285 int ip_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd);
286 int ip_tunnel_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
287 			     void __user *data, int cmd);
288 int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict);
289 int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu);
290 
291 struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
292 				   int link, __be16 flags,
293 				   __be32 remote, __be32 local,
294 				   __be32 key);
295 
296 int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
297 		  const struct tnl_ptk_info *tpi, struct metadata_dst *tun_dst,
298 		  bool log_ecn_error);
299 int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
300 			 struct ip_tunnel_parm *p, __u32 fwmark);
301 int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
302 		      struct ip_tunnel_parm *p, __u32 fwmark);
303 void ip_tunnel_setup(struct net_device *dev, unsigned int net_id);
304 
305 bool ip_tunnel_netlink_encap_parms(struct nlattr *data[],
306 				   struct ip_tunnel_encap *encap);
307 
308 void ip_tunnel_netlink_parms(struct nlattr *data[],
309 			     struct ip_tunnel_parm *parms);
310 
311 extern const struct header_ops ip_tunnel_header_ops;
312 __be16 ip_tunnel_parse_protocol(const struct sk_buff *skb);
313 
314 struct ip_tunnel_encap_ops {
315 	size_t (*encap_hlen)(struct ip_tunnel_encap *e);
316 	int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e,
317 			    u8 *protocol, struct flowi4 *fl4);
318 	int (*err_handler)(struct sk_buff *skb, u32 info);
319 };
320 
321 #define MAX_IPTUN_ENCAP_OPS 8
322 
323 extern const struct ip_tunnel_encap_ops __rcu *
324 		iptun_encaps[MAX_IPTUN_ENCAP_OPS];
325 
326 int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *op,
327 			    unsigned int num);
328 int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *op,
329 			    unsigned int num);
330 
331 int ip_tunnel_encap_setup(struct ip_tunnel *t,
332 			  struct ip_tunnel_encap *ipencap);
333 
pskb_inet_may_pull(struct sk_buff * skb)334 static inline bool pskb_inet_may_pull(struct sk_buff *skb)
335 {
336 	int nhlen;
337 
338 	switch (skb->protocol) {
339 #if IS_ENABLED(CONFIG_IPV6)
340 	case htons(ETH_P_IPV6):
341 		nhlen = sizeof(struct ipv6hdr);
342 		break;
343 #endif
344 	case htons(ETH_P_IP):
345 		nhlen = sizeof(struct iphdr);
346 		break;
347 	default:
348 		nhlen = 0;
349 	}
350 
351 	return pskb_network_may_pull(skb, nhlen);
352 }
353 
ip_encap_hlen(struct ip_tunnel_encap * e)354 static inline int ip_encap_hlen(struct ip_tunnel_encap *e)
355 {
356 	const struct ip_tunnel_encap_ops *ops;
357 	int hlen = -EINVAL;
358 
359 	if (e->type == TUNNEL_ENCAP_NONE)
360 		return 0;
361 
362 	if (e->type >= MAX_IPTUN_ENCAP_OPS)
363 		return -EINVAL;
364 
365 	rcu_read_lock();
366 	ops = rcu_dereference(iptun_encaps[e->type]);
367 	if (likely(ops && ops->encap_hlen))
368 		hlen = ops->encap_hlen(e);
369 	rcu_read_unlock();
370 
371 	return hlen;
372 }
373 
ip_tunnel_encap(struct sk_buff * skb,struct ip_tunnel * t,u8 * protocol,struct flowi4 * fl4)374 static inline int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
375 				  u8 *protocol, struct flowi4 *fl4)
376 {
377 	const struct ip_tunnel_encap_ops *ops;
378 	int ret = -EINVAL;
379 
380 	if (t->encap.type == TUNNEL_ENCAP_NONE)
381 		return 0;
382 
383 	if (t->encap.type >= MAX_IPTUN_ENCAP_OPS)
384 		return -EINVAL;
385 
386 	rcu_read_lock();
387 	ops = rcu_dereference(iptun_encaps[t->encap.type]);
388 	if (likely(ops && ops->build_header))
389 		ret = ops->build_header(skb, &t->encap, protocol, fl4);
390 	rcu_read_unlock();
391 
392 	return ret;
393 }
394 
395 /* Extract dsfield from inner protocol */
ip_tunnel_get_dsfield(const struct iphdr * iph,const struct sk_buff * skb)396 static inline u8 ip_tunnel_get_dsfield(const struct iphdr *iph,
397 				       const struct sk_buff *skb)
398 {
399 	__be16 payload_protocol = skb_protocol(skb, true);
400 
401 	if (payload_protocol == htons(ETH_P_IP))
402 		return iph->tos;
403 	else if (payload_protocol == htons(ETH_P_IPV6))
404 		return ipv6_get_dsfield((const struct ipv6hdr *)iph);
405 	else
406 		return 0;
407 }
408 
ip_tunnel_get_ttl(const struct iphdr * iph,const struct sk_buff * skb)409 static inline u8 ip_tunnel_get_ttl(const struct iphdr *iph,
410 				       const struct sk_buff *skb)
411 {
412 	__be16 payload_protocol = skb_protocol(skb, true);
413 
414 	if (payload_protocol == htons(ETH_P_IP))
415 		return iph->ttl;
416 	else if (payload_protocol == htons(ETH_P_IPV6))
417 		return ((const struct ipv6hdr *)iph)->hop_limit;
418 	else
419 		return 0;
420 }
421 
422 /* Propogate ECN bits out */
ip_tunnel_ecn_encap(u8 tos,const struct iphdr * iph,const struct sk_buff * skb)423 static inline u8 ip_tunnel_ecn_encap(u8 tos, const struct iphdr *iph,
424 				     const struct sk_buff *skb)
425 {
426 	u8 inner = ip_tunnel_get_dsfield(iph, skb);
427 
428 	return INET_ECN_encapsulate(tos, inner);
429 }
430 
431 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
432 			   __be16 inner_proto, bool raw_proto, bool xnet);
433 
iptunnel_pull_header(struct sk_buff * skb,int hdr_len,__be16 inner_proto,bool xnet)434 static inline int iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
435 				       __be16 inner_proto, bool xnet)
436 {
437 	return __iptunnel_pull_header(skb, hdr_len, inner_proto, false, xnet);
438 }
439 
440 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
441 		   __be32 src, __be32 dst, u8 proto,
442 		   u8 tos, u8 ttl, __be16 df, bool xnet);
443 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
444 					     gfp_t flags);
445 int skb_tunnel_check_pmtu(struct sk_buff *skb, struct dst_entry *encap_dst,
446 			  int headroom, bool reply);
447 
448 int iptunnel_handle_offloads(struct sk_buff *skb, int gso_type_mask);
449 
iptunnel_pull_offloads(struct sk_buff * skb)450 static inline int iptunnel_pull_offloads(struct sk_buff *skb)
451 {
452 	if (skb_is_gso(skb)) {
453 		int err;
454 
455 		err = skb_unclone(skb, GFP_ATOMIC);
456 		if (unlikely(err))
457 			return err;
458 		skb_shinfo(skb)->gso_type &= ~(NETIF_F_GSO_ENCAP_ALL >>
459 					       NETIF_F_GSO_SHIFT);
460 	}
461 
462 	skb->encapsulation = 0;
463 	return 0;
464 }
465 
iptunnel_xmit_stats(struct net_device * dev,int pkt_len)466 static inline void iptunnel_xmit_stats(struct net_device *dev, int pkt_len)
467 {
468 	if (pkt_len > 0) {
469 		struct pcpu_sw_netstats *tstats = get_cpu_ptr(dev->tstats);
470 
471 		u64_stats_update_begin(&tstats->syncp);
472 		u64_stats_add(&tstats->tx_bytes, pkt_len);
473 		u64_stats_inc(&tstats->tx_packets);
474 		u64_stats_update_end(&tstats->syncp);
475 		put_cpu_ptr(tstats);
476 	} else {
477 		struct net_device_stats *err_stats = &dev->stats;
478 
479 		if (pkt_len < 0) {
480 			err_stats->tx_errors++;
481 			err_stats->tx_aborted_errors++;
482 		} else {
483 			err_stats->tx_dropped++;
484 		}
485 	}
486 }
487 
ip_tunnel_info_opts(struct ip_tunnel_info * info)488 static inline void *ip_tunnel_info_opts(struct ip_tunnel_info *info)
489 {
490 	return info + 1;
491 }
492 
ip_tunnel_info_opts_get(void * to,const struct ip_tunnel_info * info)493 static inline void ip_tunnel_info_opts_get(void *to,
494 					   const struct ip_tunnel_info *info)
495 {
496 	memcpy(to, info + 1, info->options_len);
497 }
498 
ip_tunnel_info_opts_set(struct ip_tunnel_info * info,const void * from,int len,__be16 flags)499 static inline void ip_tunnel_info_opts_set(struct ip_tunnel_info *info,
500 					   const void *from, int len,
501 					   __be16 flags)
502 {
503 	info->options_len = len;
504 	if (len > 0) {
505 		memcpy(ip_tunnel_info_opts(info), from, len);
506 		info->key.tun_flags |= flags;
507 	}
508 }
509 
lwt_tun_info(struct lwtunnel_state * lwtstate)510 static inline struct ip_tunnel_info *lwt_tun_info(struct lwtunnel_state *lwtstate)
511 {
512 	return (struct ip_tunnel_info *)lwtstate->data;
513 }
514 
515 DECLARE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
516 
517 /* Returns > 0 if metadata should be collected */
ip_tunnel_collect_metadata(void)518 static inline int ip_tunnel_collect_metadata(void)
519 {
520 	return static_branch_unlikely(&ip_tunnel_metadata_cnt);
521 }
522 
523 void __init ip_tunnel_core_init(void);
524 
525 void ip_tunnel_need_metadata(void);
526 void ip_tunnel_unneed_metadata(void);
527 
528 #else /* CONFIG_INET */
529 
lwt_tun_info(struct lwtunnel_state * lwtstate)530 static inline struct ip_tunnel_info *lwt_tun_info(struct lwtunnel_state *lwtstate)
531 {
532 	return NULL;
533 }
534 
ip_tunnel_need_metadata(void)535 static inline void ip_tunnel_need_metadata(void)
536 {
537 }
538 
ip_tunnel_unneed_metadata(void)539 static inline void ip_tunnel_unneed_metadata(void)
540 {
541 }
542 
ip_tunnel_info_opts_get(void * to,const struct ip_tunnel_info * info)543 static inline void ip_tunnel_info_opts_get(void *to,
544 					   const struct ip_tunnel_info *info)
545 {
546 }
547 
ip_tunnel_info_opts_set(struct ip_tunnel_info * info,const void * from,int len,__be16 flags)548 static inline void ip_tunnel_info_opts_set(struct ip_tunnel_info *info,
549 					   const void *from, int len,
550 					   __be16 flags)
551 {
552 	info->options_len = 0;
553 }
554 
555 #endif /* CONFIG_INET */
556 
557 #endif /* __NET_IP_TUNNELS_H */
558