xref: /linux/include/net/ipv6.h (revision 405849610fd96b4f34cd1875c4c033228fea6c0f)
1 /*
2  *	Linux INET6 implementation
3  *
4  *	Authors:
5  *	Pedro Roque		<roque@di.fc.ul.pt>
6  *
7  *	$Id: ipv6.h,v 1.1 2002/05/20 15:13:07 jgrimm Exp $
8  *
9  *	This program is free software; you can redistribute it and/or
10  *      modify it under the terms of the GNU General Public License
11  *      as published by the Free Software Foundation; either version
12  *      2 of the License, or (at your option) any later version.
13  */
14 
15 #ifndef _NET_IPV6_H
16 #define _NET_IPV6_H
17 
18 #include <linux/ipv6.h>
19 #include <linux/hardirq.h>
20 #include <net/if_inet6.h>
21 #include <net/ndisc.h>
22 #include <net/flow.h>
23 #include <net/snmp.h>
24 
25 #define SIN6_LEN_RFC2133	24
26 
27 #define IPV6_MAXPLEN		65535
28 
29 /*
30  *	NextHeader field of IPv6 header
31  */
32 
33 #define NEXTHDR_HOP		0	/* Hop-by-hop option header. */
34 #define NEXTHDR_TCP		6	/* TCP segment. */
35 #define NEXTHDR_UDP		17	/* UDP message. */
36 #define NEXTHDR_IPV6		41	/* IPv6 in IPv6 */
37 #define NEXTHDR_ROUTING		43	/* Routing header. */
38 #define NEXTHDR_FRAGMENT	44	/* Fragmentation/reassembly header. */
39 #define NEXTHDR_ESP		50	/* Encapsulating security payload. */
40 #define NEXTHDR_AUTH		51	/* Authentication header. */
41 #define NEXTHDR_ICMP		58	/* ICMP for IPv6. */
42 #define NEXTHDR_NONE		59	/* No next header */
43 #define NEXTHDR_DEST		60	/* Destination options header. */
44 #define NEXTHDR_MOBILITY	135	/* Mobility header. */
45 
46 #define NEXTHDR_MAX		255
47 
48 
49 
50 #define IPV6_DEFAULT_HOPLIMIT   64
51 #define IPV6_DEFAULT_MCASTHOPS	1
52 
53 /*
54  *	Addr type
55  *
56  *	type	-	unicast | multicast
57  *	scope	-	local	| site	    | global
58  *	v4	-	compat
59  *	v4mapped
60  *	any
61  *	loopback
62  */
63 
64 #define IPV6_ADDR_ANY		0x0000U
65 
66 #define IPV6_ADDR_UNICAST      	0x0001U
67 #define IPV6_ADDR_MULTICAST    	0x0002U
68 
69 #define IPV6_ADDR_LOOPBACK	0x0010U
70 #define IPV6_ADDR_LINKLOCAL	0x0020U
71 #define IPV6_ADDR_SITELOCAL	0x0040U
72 
73 #define IPV6_ADDR_COMPATv4	0x0080U
74 
75 #define IPV6_ADDR_SCOPE_MASK	0x00f0U
76 
77 #define IPV6_ADDR_MAPPED	0x1000U
78 #define IPV6_ADDR_RESERVED	0x2000U	/* reserved address space */
79 
80 /*
81  *	Addr scopes
82  */
83 #ifdef __KERNEL__
84 #define IPV6_ADDR_MC_SCOPE(a)	\
85 	((a)->s6_addr[1] & 0x0f)	/* nonstandard */
86 #define __IPV6_ADDR_SCOPE_INVALID	-1
87 #endif
88 #define IPV6_ADDR_SCOPE_NODELOCAL	0x01
89 #define IPV6_ADDR_SCOPE_LINKLOCAL	0x02
90 #define IPV6_ADDR_SCOPE_SITELOCAL	0x05
91 #define IPV6_ADDR_SCOPE_ORGLOCAL	0x08
92 #define IPV6_ADDR_SCOPE_GLOBAL		0x0e
93 
94 /*
95  *	fragmentation header
96  */
97 
98 struct frag_hdr {
99 	__u8	nexthdr;
100 	__u8	reserved;
101 	__be16	frag_off;
102 	__be32	identification;
103 };
104 
105 #define	IP6_MF	0x0001
106 
107 #ifdef __KERNEL__
108 
109 #include <net/sock.h>
110 
111 /* sysctls */
112 extern int sysctl_ipv6_bindv6only;
113 extern int sysctl_mld_max_msf;
114 
115 /* MIBs */
116 DECLARE_SNMP_STAT(struct ipstats_mib, ipv6_statistics);
117 #define IP6_INC_STATS(idev,field)		({			\
118 	struct inet6_dev *_idev = (idev);				\
119 	if (likely(_idev != NULL))					\
120 		SNMP_INC_STATS(_idev->stats.ipv6, field);		\
121 	SNMP_INC_STATS(ipv6_statistics, field);				\
122 })
123 #define IP6_INC_STATS_BH(idev,field)		({			\
124 	struct inet6_dev *_idev = (idev);				\
125 	if (likely(_idev != NULL))					\
126 		SNMP_INC_STATS_BH(_idev->stats.ipv6, field);		\
127 	SNMP_INC_STATS_BH(ipv6_statistics, field);			\
128 })
129 #define IP6_INC_STATS_USER(idev,field)		({			\
130 	struct inet6_dev *_idev = (idev);				\
131 	if (likely(_idev != NULL))					\
132 		SNMP_INC_STATS_USER(_idev->stats.ipv6, field);		\
133 	SNMP_INC_STATS_USER(ipv6_statistics, field);			\
134 })
135 DECLARE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics);
136 #define ICMP6_INC_STATS(idev, field)		({			\
137 	struct inet6_dev *_idev = (idev);				\
138 	if (likely(_idev != NULL))					\
139 		SNMP_INC_STATS(idev->stats.icmpv6, field); 		\
140 	SNMP_INC_STATS(icmpv6_statistics, field);			\
141 })
142 #define ICMP6_INC_STATS_BH(idev, field)		({			\
143 	struct inet6_dev *_idev = (idev);				\
144 	if (likely(_idev != NULL))					\
145 		SNMP_INC_STATS_BH((_idev)->stats.icmpv6, field);	\
146 	SNMP_INC_STATS_BH(icmpv6_statistics, field);			\
147 })
148 #define ICMP6_INC_STATS_USER(idev, field) 	({			\
149 	struct inet6_dev *_idev = (idev);				\
150 	if (likely(_idev != NULL))					\
151 		SNMP_INC_STATS_USER(_idev->stats.icmpv6, field);	\
152 	SNMP_INC_STATS_USER(icmpv6_statistics, field);			\
153 })
154 #define ICMP6_INC_STATS_OFFSET_BH(idev, field, offset)	({			\
155 	struct inet6_dev *_idev = idev;						\
156 	__typeof__(offset) _offset = (offset);					\
157 	if (likely(_idev != NULL))						\
158 		SNMP_INC_STATS_OFFSET_BH(_idev->stats.icmpv6, field, _offset);	\
159 	SNMP_INC_STATS_OFFSET_BH(icmpv6_statistics, field, _offset);    	\
160 })
161 DECLARE_SNMP_STAT(struct udp_mib, udp_stats_in6);
162 DECLARE_SNMP_STAT(struct udp_mib, udplite_stats_in6);
163 #define UDP6_INC_STATS_BH(field, is_udplite) 			      do  {  \
164 	if (is_udplite) SNMP_INC_STATS_BH(udplite_stats_in6, field);         \
165 	else		SNMP_INC_STATS_BH(udp_stats_in6, field);    } while(0)
166 #define UDP6_INC_STATS_USER(field, is_udplite)			       do {    \
167 	if (is_udplite) SNMP_INC_STATS_USER(udplite_stats_in6, field);         \
168 	else		SNMP_INC_STATS_USER(udp_stats_in6, field);    } while(0)
169 
170 struct ip6_ra_chain
171 {
172 	struct ip6_ra_chain	*next;
173 	struct sock		*sk;
174 	int			sel;
175 	void			(*destructor)(struct sock *);
176 };
177 
178 extern struct ip6_ra_chain	*ip6_ra_chain;
179 extern rwlock_t ip6_ra_lock;
180 
181 /*
182    This structure is prepared by protocol, when parsing
183    ancillary data and passed to IPv6.
184  */
185 
186 struct ipv6_txoptions
187 {
188 	/* Length of this structure */
189 	int			tot_len;
190 
191 	/* length of extension headers   */
192 
193 	__u16			opt_flen;	/* after fragment hdr */
194 	__u16			opt_nflen;	/* before fragment hdr */
195 
196 	struct ipv6_opt_hdr	*hopopt;
197 	struct ipv6_opt_hdr	*dst0opt;
198 	struct ipv6_rt_hdr	*srcrt;	/* Routing Header */
199 	struct ipv6_opt_hdr	*dst1opt;
200 
201 	/* Option buffer, as read by IPV6_PKTOPTIONS, starts here. */
202 };
203 
204 struct ip6_flowlabel
205 {
206 	struct ip6_flowlabel	*next;
207 	__be32			label;
208 	atomic_t		users;
209 	struct in6_addr		dst;
210 	struct ipv6_txoptions	*opt;
211 	unsigned long		linger;
212 	u8			share;
213 	u32			owner;
214 	unsigned long		lastuse;
215 	unsigned long		expires;
216 };
217 
218 #define IPV6_FLOWINFO_MASK	__constant_htonl(0x0FFFFFFF)
219 #define IPV6_FLOWLABEL_MASK	__constant_htonl(0x000FFFFF)
220 
221 struct ipv6_fl_socklist
222 {
223 	struct ipv6_fl_socklist	*next;
224 	struct ip6_flowlabel	*fl;
225 };
226 
227 extern struct ip6_flowlabel	*fl6_sock_lookup(struct sock *sk, __be32 label);
228 extern struct ipv6_txoptions	*fl6_merge_options(struct ipv6_txoptions * opt_space,
229 						   struct ip6_flowlabel * fl,
230 						   struct ipv6_txoptions * fopt);
231 extern void			fl6_free_socklist(struct sock *sk);
232 extern int			ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen);
233 extern void			ip6_flowlabel_init(void);
234 extern void			ip6_flowlabel_cleanup(void);
235 
236 static inline void fl6_sock_release(struct ip6_flowlabel *fl)
237 {
238 	if (fl)
239 		atomic_dec(&fl->users);
240 }
241 
242 extern int 			ip6_ra_control(struct sock *sk, int sel,
243 					       void (*destructor)(struct sock *));
244 
245 
246 extern int			ipv6_parse_hopopts(struct sk_buff **skbp);
247 
248 extern struct ipv6_txoptions *  ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt);
249 extern struct ipv6_txoptions *	ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
250 						   int newtype,
251 						   struct ipv6_opt_hdr __user *newopt,
252 						   int newoptlen);
253 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
254 					  struct ipv6_txoptions *opt);
255 
256 extern int ipv6_opt_accepted(struct sock *sk, struct sk_buff *skb);
257 
258 extern int ip6_frag_nqueues;
259 extern atomic_t ip6_frag_mem;
260 
261 #define IPV6_FRAG_TIMEOUT	(60*HZ)		/* 60 seconds */
262 
263 /*
264  *	Function prototype for build_xmit
265  */
266 
267 typedef int		(*inet_getfrag_t) (const void *data,
268 					   struct in6_addr *addr,
269 					   char *,
270 					   unsigned int, unsigned int);
271 
272 extern int __ipv6_addr_type(const struct in6_addr *addr);
273 static inline int ipv6_addr_type(const struct in6_addr *addr)
274 {
275 	return __ipv6_addr_type(addr) & 0xffff;
276 }
277 
278 static inline int ipv6_addr_scope(const struct in6_addr *addr)
279 {
280 	return __ipv6_addr_type(addr) & IPV6_ADDR_SCOPE_MASK;
281 }
282 
283 static inline int __ipv6_addr_src_scope(int type)
284 {
285 	return (type == IPV6_ADDR_ANY ? __IPV6_ADDR_SCOPE_INVALID : (type >> 16));
286 }
287 
288 static inline int ipv6_addr_src_scope(const struct in6_addr *addr)
289 {
290 	return __ipv6_addr_src_scope(__ipv6_addr_type(addr));
291 }
292 
293 static inline int ipv6_addr_cmp(const struct in6_addr *a1, const struct in6_addr *a2)
294 {
295 	return memcmp(a1, a2, sizeof(struct in6_addr));
296 }
297 
298 static inline int
299 ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m,
300 		     const struct in6_addr *a2)
301 {
302 	unsigned int i;
303 
304 	for (i = 0; i < 4; i++)
305 		if ((a1->s6_addr32[i] ^ a2->s6_addr32[i]) & m->s6_addr32[i])
306 			return 1;
307 	return 0;
308 }
309 
310 static inline void ipv6_addr_copy(struct in6_addr *a1, const struct in6_addr *a2)
311 {
312 	memcpy(a1, a2, sizeof(struct in6_addr));
313 }
314 
315 static inline void ipv6_addr_prefix(struct in6_addr *pfx,
316 				    const struct in6_addr *addr,
317 				    int plen)
318 {
319 	/* caller must guarantee 0 <= plen <= 128 */
320 	int o = plen >> 3,
321 	    b = plen & 0x7;
322 
323 	memset(pfx->s6_addr, 0, sizeof(pfx->s6_addr));
324 	memcpy(pfx->s6_addr, addr, o);
325 	if (b != 0)
326 		pfx->s6_addr[o] = addr->s6_addr[o] & (0xff00 >> b);
327 }
328 
329 static inline void ipv6_addr_set(struct in6_addr *addr,
330 				     __be32 w1, __be32 w2,
331 				     __be32 w3, __be32 w4)
332 {
333 	addr->s6_addr32[0] = w1;
334 	addr->s6_addr32[1] = w2;
335 	addr->s6_addr32[2] = w3;
336 	addr->s6_addr32[3] = w4;
337 }
338 
339 static inline int ipv6_addr_equal(const struct in6_addr *a1,
340 				  const struct in6_addr *a2)
341 {
342 	return (a1->s6_addr32[0] == a2->s6_addr32[0] &&
343 		a1->s6_addr32[1] == a2->s6_addr32[1] &&
344 		a1->s6_addr32[2] == a2->s6_addr32[2] &&
345 		a1->s6_addr32[3] == a2->s6_addr32[3]);
346 }
347 
348 static inline int __ipv6_prefix_equal(const __be32 *a1, const __be32 *a2,
349 				      unsigned int prefixlen)
350 {
351 	unsigned pdw, pbi;
352 
353 	/* check complete u32 in prefix */
354 	pdw = prefixlen >> 5;
355 	if (pdw && memcmp(a1, a2, pdw << 2))
356 		return 0;
357 
358 	/* check incomplete u32 in prefix */
359 	pbi = prefixlen & 0x1f;
360 	if (pbi && ((a1[pdw] ^ a2[pdw]) & htonl((0xffffffff) << (32 - pbi))))
361 		return 0;
362 
363 	return 1;
364 }
365 
366 static inline int ipv6_prefix_equal(const struct in6_addr *a1,
367 				    const struct in6_addr *a2,
368 				    unsigned int prefixlen)
369 {
370 	return __ipv6_prefix_equal(a1->s6_addr32, a2->s6_addr32,
371 				   prefixlen);
372 }
373 
374 static inline int ipv6_addr_any(const struct in6_addr *a)
375 {
376 	return ((a->s6_addr32[0] | a->s6_addr32[1] |
377 		 a->s6_addr32[2] | a->s6_addr32[3] ) == 0);
378 }
379 
380 /*
381  * find the first different bit between two addresses
382  * length of address must be a multiple of 32bits
383  */
384 static inline int __ipv6_addr_diff(const void *token1, const void *token2, int addrlen)
385 {
386 	const __be32 *a1 = token1, *a2 = token2;
387 	int i;
388 
389 	addrlen >>= 2;
390 
391 	for (i = 0; i < addrlen; i++) {
392 		__be32 xb = a1[i] ^ a2[i];
393 		if (xb)
394 			return i * 32 + 32 - fls(ntohl(xb));
395 	}
396 
397 	/*
398 	 *	we should *never* get to this point since that
399 	 *	would mean the addrs are equal
400 	 *
401 	 *	However, we do get to it 8) And exacly, when
402 	 *	addresses are equal 8)
403 	 *
404 	 *	ip route add 1111::/128 via ...
405 	 *	ip route add 1111::/64 via ...
406 	 *	and we are here.
407 	 *
408 	 *	Ideally, this function should stop comparison
409 	 *	at prefix length. It does not, but it is still OK,
410 	 *	if returned value is greater than prefix length.
411 	 *					--ANK (980803)
412 	 */
413 	return (addrlen << 5);
414 }
415 
416 static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_addr *a2)
417 {
418 	return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr));
419 }
420 
421 /*
422  *	Prototypes exported by ipv6
423  */
424 
425 /*
426  *	rcv function (called from netdevice level)
427  */
428 
429 extern int			ipv6_rcv(struct sk_buff *skb,
430 					 struct net_device *dev,
431 					 struct packet_type *pt,
432 					 struct net_device *orig_dev);
433 
434 extern int			ip6_rcv_finish(struct sk_buff *skb);
435 
436 /*
437  *	upper-layer output functions
438  */
439 extern int			ip6_xmit(struct sock *sk,
440 					 struct sk_buff *skb,
441 					 struct flowi *fl,
442 					 struct ipv6_txoptions *opt,
443 					 int ipfragok);
444 
445 extern int			ip6_nd_hdr(struct sock *sk,
446 					   struct sk_buff *skb,
447 					   struct net_device *dev,
448 					   struct in6_addr *saddr,
449 					   struct in6_addr *daddr,
450 					   int proto, int len);
451 
452 extern int			ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr);
453 
454 extern int			ip6_append_data(struct sock *sk,
455 						int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb),
456 		    				void *from,
457 						int length,
458 						int transhdrlen,
459 		      				int hlimit,
460 		      				int tclass,
461 						struct ipv6_txoptions *opt,
462 						struct flowi *fl,
463 						struct rt6_info *rt,
464 						unsigned int flags);
465 
466 extern int			ip6_push_pending_frames(struct sock *sk);
467 
468 extern void			ip6_flush_pending_frames(struct sock *sk);
469 
470 extern int			ip6_dst_lookup(struct sock *sk,
471 					       struct dst_entry **dst,
472 					       struct flowi *fl);
473 extern int			ip6_dst_blackhole(struct sock *sk,
474 						  struct dst_entry **dst,
475 						  struct flowi *fl);
476 extern int			ip6_sk_dst_lookup(struct sock *sk,
477 						  struct dst_entry **dst,
478 						  struct flowi *fl);
479 
480 /*
481  *	skb processing functions
482  */
483 
484 extern int			ip6_output(struct sk_buff *skb);
485 extern int			ip6_forward(struct sk_buff *skb);
486 extern int			ip6_input(struct sk_buff *skb);
487 extern int			ip6_mc_input(struct sk_buff *skb);
488 
489 /*
490  *	Extension header (options) processing
491  */
492 
493 extern u8 *			ipv6_build_nfrag_opts(struct sk_buff *skb,
494 						      u8 *prev_hdr,
495 						      struct ipv6_txoptions *opt,
496 						      struct in6_addr *daddr,
497 						      u32 jumbolen);
498 extern u8 *			ipv6_build_frag_opts(struct sk_buff *skb,
499 						     u8 *prev_hdr,
500 						     struct ipv6_txoptions *opt);
501 extern void 			ipv6_push_nfrag_opts(struct sk_buff *skb,
502 						     struct ipv6_txoptions *opt,
503 						     u8 *proto,
504 						     struct in6_addr **daddr_p);
505 extern void			ipv6_push_frag_opts(struct sk_buff *skb,
506 						    struct ipv6_txoptions *opt,
507 						    u8 *proto);
508 
509 extern int			ipv6_skip_exthdr(const struct sk_buff *, int start,
510 					         u8 *nexthdrp);
511 
512 extern int 			ipv6_ext_hdr(u8 nexthdr);
513 
514 extern int ipv6_find_tlv(struct sk_buff *skb, int offset, int type);
515 
516 /*
517  *	socket options (ipv6_sockglue.c)
518  */
519 
520 extern int			ipv6_setsockopt(struct sock *sk, int level,
521 						int optname,
522 						char __user *optval,
523 						int optlen);
524 extern int			ipv6_getsockopt(struct sock *sk, int level,
525 						int optname,
526 						char __user *optval,
527 						int __user *optlen);
528 extern int			compat_ipv6_setsockopt(struct sock *sk,
529 						int level,
530 						int optname,
531 						char __user *optval,
532 						int optlen);
533 extern int			compat_ipv6_getsockopt(struct sock *sk,
534 						int level,
535 						int optname,
536 						char __user *optval,
537 						int __user *optlen);
538 
539 extern void			ipv6_packet_init(void);
540 
541 extern void			ipv6_packet_cleanup(void);
542 
543 extern int			ip6_datagram_connect(struct sock *sk,
544 						     struct sockaddr *addr, int addr_len);
545 
546 extern int 			ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len);
547 extern void			ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
548 						u32 info, u8 *payload);
549 extern void			ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info);
550 
551 extern int inet6_release(struct socket *sock);
552 extern int inet6_bind(struct socket *sock, struct sockaddr *uaddr,
553 		      int addr_len);
554 extern int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
555 			 int *uaddr_len, int peer);
556 extern int inet6_ioctl(struct socket *sock, unsigned int cmd,
557 		       unsigned long arg);
558 
559 extern int inet6_hash_connect(struct inet_timewait_death_row *death_row,
560 			      struct sock *sk);
561 
562 /*
563  * reassembly.c
564  */
565 extern int sysctl_ip6frag_high_thresh;
566 extern int sysctl_ip6frag_low_thresh;
567 extern int sysctl_ip6frag_time;
568 extern int sysctl_ip6frag_secret_interval;
569 
570 extern const struct proto_ops inet6_stream_ops;
571 extern const struct proto_ops inet6_dgram_ops;
572 
573 struct group_source_req;
574 struct group_filter;
575 
576 extern int ip6_mc_source(int add, int omode, struct sock *sk,
577 			 struct group_source_req *pgsr);
578 extern int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf);
579 extern int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
580 			 struct group_filter __user *optval,
581 			 int __user *optlen);
582 
583 #ifdef CONFIG_PROC_FS
584 extern int  ac6_proc_init(void);
585 extern void ac6_proc_exit(void);
586 extern int  raw6_proc_init(void);
587 extern void raw6_proc_exit(void);
588 extern int  tcp6_proc_init(void);
589 extern void tcp6_proc_exit(void);
590 extern int  udp6_proc_init(void);
591 extern void udp6_proc_exit(void);
592 extern int  udplite6_proc_init(void);
593 extern void udplite6_proc_exit(void);
594 extern int  ipv6_misc_proc_init(void);
595 extern void ipv6_misc_proc_exit(void);
596 extern int snmp6_register_dev(struct inet6_dev *idev);
597 extern int snmp6_unregister_dev(struct inet6_dev *idev);
598 
599 extern struct rt6_statistics rt6_stats;
600 #else
601 static inline int snmp6_register_dev(struct inet6_dev *idev)
602 {
603 	return 0;
604 }
605 
606 static inline int snmp6_unregister_dev(struct inet6_dev *idev)
607 {
608 	return 0;
609 }
610 #endif
611 
612 #ifdef CONFIG_SYSCTL
613 extern ctl_table ipv6_route_table[];
614 extern ctl_table ipv6_icmp_table[];
615 
616 extern void ipv6_sysctl_register(void);
617 extern void ipv6_sysctl_unregister(void);
618 #endif
619 
620 #endif /* __KERNEL__ */
621 #endif /* _NET_IPV6_H */
622