xref: /openbmc/linux/include/net/ipv6.h (revision 9d749629)
1 /*
2  *	Linux INET6 implementation
3  *
4  *	Authors:
5  *	Pedro Roque		<roque@di.fc.ul.pt>
6  *
7  *	This program is free software; you can redistribute it and/or
8  *      modify it under the terms of the GNU General Public License
9  *      as published by the Free Software Foundation; either version
10  *      2 of the License, or (at your option) any later version.
11  */
12 
13 #ifndef _NET_IPV6_H
14 #define _NET_IPV6_H
15 
16 #include <linux/ipv6.h>
17 #include <linux/hardirq.h>
18 #include <net/if_inet6.h>
19 #include <net/ndisc.h>
20 #include <net/flow.h>
21 #include <net/snmp.h>
22 
23 #define SIN6_LEN_RFC2133	24
24 
25 #define IPV6_MAXPLEN		65535
26 
27 /*
28  *	NextHeader field of IPv6 header
29  */
30 
31 #define NEXTHDR_HOP		0	/* Hop-by-hop option header. */
32 #define NEXTHDR_TCP		6	/* TCP segment. */
33 #define NEXTHDR_UDP		17	/* UDP message. */
34 #define NEXTHDR_IPV6		41	/* IPv6 in IPv6 */
35 #define NEXTHDR_ROUTING		43	/* Routing header. */
36 #define NEXTHDR_FRAGMENT	44	/* Fragmentation/reassembly header. */
37 #define NEXTHDR_GRE		47	/* GRE header. */
38 #define NEXTHDR_ESP		50	/* Encapsulating security payload. */
39 #define NEXTHDR_AUTH		51	/* Authentication header. */
40 #define NEXTHDR_ICMP		58	/* ICMP for IPv6. */
41 #define NEXTHDR_NONE		59	/* No next header */
42 #define NEXTHDR_DEST		60	/* Destination options header. */
43 #define NEXTHDR_MOBILITY	135	/* Mobility header. */
44 
45 #define NEXTHDR_MAX		255
46 
47 
48 
49 #define IPV6_DEFAULT_HOPLIMIT   64
50 #define IPV6_DEFAULT_MCASTHOPS	1
51 
52 /*
53  *	Addr type
54  *
55  *	type	-	unicast | multicast
56  *	scope	-	local	| site	    | global
57  *	v4	-	compat
58  *	v4mapped
59  *	any
60  *	loopback
61  */
62 
63 #define IPV6_ADDR_ANY		0x0000U
64 
65 #define IPV6_ADDR_UNICAST      	0x0001U
66 #define IPV6_ADDR_MULTICAST    	0x0002U
67 
68 #define IPV6_ADDR_LOOPBACK	0x0010U
69 #define IPV6_ADDR_LINKLOCAL	0x0020U
70 #define IPV6_ADDR_SITELOCAL	0x0040U
71 
72 #define IPV6_ADDR_COMPATv4	0x0080U
73 
74 #define IPV6_ADDR_SCOPE_MASK	0x00f0U
75 
76 #define IPV6_ADDR_MAPPED	0x1000U
77 
78 /*
79  *	Addr scopes
80  */
81 #define IPV6_ADDR_MC_SCOPE(a)	\
82 	((a)->s6_addr[1] & 0x0f)	/* nonstandard */
83 #define __IPV6_ADDR_SCOPE_INVALID	-1
84 #define IPV6_ADDR_SCOPE_NODELOCAL	0x01
85 #define IPV6_ADDR_SCOPE_LINKLOCAL	0x02
86 #define IPV6_ADDR_SCOPE_SITELOCAL	0x05
87 #define IPV6_ADDR_SCOPE_ORGLOCAL	0x08
88 #define IPV6_ADDR_SCOPE_GLOBAL		0x0e
89 
90 /*
91  *	Addr flags
92  */
93 #define IPV6_ADDR_MC_FLAG_TRANSIENT(a)	\
94 	((a)->s6_addr[1] & 0x10)
95 #define IPV6_ADDR_MC_FLAG_PREFIX(a)	\
96 	((a)->s6_addr[1] & 0x20)
97 #define IPV6_ADDR_MC_FLAG_RENDEZVOUS(a)	\
98 	((a)->s6_addr[1] & 0x40)
99 
100 /*
101  *	fragmentation header
102  */
103 
104 struct frag_hdr {
105 	__u8	nexthdr;
106 	__u8	reserved;
107 	__be16	frag_off;
108 	__be32	identification;
109 };
110 
111 #define	IP6_MF	0x0001
112 
113 #include <net/sock.h>
114 
115 /* sysctls */
116 extern int sysctl_mld_max_msf;
117 
118 #define _DEVINC(net, statname, modifier, idev, field)			\
119 ({									\
120 	struct inet6_dev *_idev = (idev);				\
121 	if (likely(_idev != NULL))					\
122 		SNMP_INC_STATS##modifier((_idev)->stats.statname, (field)); \
123 	SNMP_INC_STATS##modifier((net)->mib.statname##_statistics, (field));\
124 })
125 
126 /* per device counters are atomic_long_t */
127 #define _DEVINCATOMIC(net, statname, modifier, idev, field)		\
128 ({									\
129 	struct inet6_dev *_idev = (idev);				\
130 	if (likely(_idev != NULL))					\
131 		SNMP_INC_STATS_ATOMIC_LONG((_idev)->stats.statname##dev, (field)); \
132 	SNMP_INC_STATS##modifier((net)->mib.statname##_statistics, (field));\
133 })
134 
135 /* per device and per net counters are atomic_long_t */
136 #define _DEVINC_ATOMIC_ATOMIC(net, statname, idev, field)		\
137 ({									\
138 	struct inet6_dev *_idev = (idev);				\
139 	if (likely(_idev != NULL))					\
140 		SNMP_INC_STATS_ATOMIC_LONG((_idev)->stats.statname##dev, (field)); \
141 	SNMP_INC_STATS_ATOMIC_LONG((net)->mib.statname##_statistics, (field));\
142 })
143 
144 #define _DEVADD(net, statname, modifier, idev, field, val)		\
145 ({									\
146 	struct inet6_dev *_idev = (idev);				\
147 	if (likely(_idev != NULL))					\
148 		SNMP_ADD_STATS##modifier((_idev)->stats.statname, (field), (val)); \
149 	SNMP_ADD_STATS##modifier((net)->mib.statname##_statistics, (field), (val));\
150 })
151 
152 #define _DEVUPD(net, statname, modifier, idev, field, val)		\
153 ({									\
154 	struct inet6_dev *_idev = (idev);				\
155 	if (likely(_idev != NULL))					\
156 		SNMP_UPD_PO_STATS##modifier((_idev)->stats.statname, field, (val)); \
157 	SNMP_UPD_PO_STATS##modifier((net)->mib.statname##_statistics, field, (val));\
158 })
159 
160 /* MIBs */
161 
162 #define IP6_INC_STATS(net, idev,field)		\
163 		_DEVINC(net, ipv6, 64, idev, field)
164 #define IP6_INC_STATS_BH(net, idev,field)	\
165 		_DEVINC(net, ipv6, 64_BH, idev, field)
166 #define IP6_ADD_STATS(net, idev,field,val)	\
167 		_DEVADD(net, ipv6, 64, idev, field, val)
168 #define IP6_ADD_STATS_BH(net, idev,field,val)	\
169 		_DEVADD(net, ipv6, 64_BH, idev, field, val)
170 #define IP6_UPD_PO_STATS(net, idev,field,val)   \
171 		_DEVUPD(net, ipv6, 64, idev, field, val)
172 #define IP6_UPD_PO_STATS_BH(net, idev,field,val)   \
173 		_DEVUPD(net, ipv6, 64_BH, idev, field, val)
174 #define ICMP6_INC_STATS(net, idev, field)	\
175 		_DEVINCATOMIC(net, icmpv6, , idev, field)
176 #define ICMP6_INC_STATS_BH(net, idev, field)	\
177 		_DEVINCATOMIC(net, icmpv6, _BH, idev, field)
178 
179 #define ICMP6MSGOUT_INC_STATS(net, idev, field)		\
180 	_DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field +256)
181 #define ICMP6MSGOUT_INC_STATS_BH(net, idev, field)	\
182 	_DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field +256)
183 #define ICMP6MSGIN_INC_STATS_BH(net, idev, field)	\
184 	_DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field)
185 
186 struct ip6_ra_chain {
187 	struct ip6_ra_chain	*next;
188 	struct sock		*sk;
189 	int			sel;
190 	void			(*destructor)(struct sock *);
191 };
192 
193 extern struct ip6_ra_chain	*ip6_ra_chain;
194 extern rwlock_t ip6_ra_lock;
195 
196 /*
197    This structure is prepared by protocol, when parsing
198    ancillary data and passed to IPv6.
199  */
200 
201 struct ipv6_txoptions {
202 	/* Length of this structure */
203 	int			tot_len;
204 
205 	/* length of extension headers   */
206 
207 	__u16			opt_flen;	/* after fragment hdr */
208 	__u16			opt_nflen;	/* before fragment hdr */
209 
210 	struct ipv6_opt_hdr	*hopopt;
211 	struct ipv6_opt_hdr	*dst0opt;
212 	struct ipv6_rt_hdr	*srcrt;	/* Routing Header */
213 	struct ipv6_opt_hdr	*dst1opt;
214 
215 	/* Option buffer, as read by IPV6_PKTOPTIONS, starts here. */
216 };
217 
218 struct ip6_flowlabel {
219 	struct ip6_flowlabel	*next;
220 	__be32			label;
221 	atomic_t		users;
222 	struct in6_addr		dst;
223 	struct ipv6_txoptions	*opt;
224 	unsigned long		linger;
225 	struct rcu_head		rcu;
226 	u8			share;
227 	union {
228 		struct pid *pid;
229 		kuid_t uid;
230 	} owner;
231 	unsigned long		lastuse;
232 	unsigned long		expires;
233 	struct net		*fl_net;
234 };
235 
236 #define IPV6_FLOWINFO_MASK	cpu_to_be32(0x0FFFFFFF)
237 #define IPV6_FLOWLABEL_MASK	cpu_to_be32(0x000FFFFF)
238 
239 struct ipv6_fl_socklist {
240 	struct ipv6_fl_socklist	*next;
241 	struct ip6_flowlabel	*fl;
242 	struct rcu_head		rcu;
243 };
244 
245 extern struct ip6_flowlabel	*fl6_sock_lookup(struct sock *sk, __be32 label);
246 extern struct ipv6_txoptions	*fl6_merge_options(struct ipv6_txoptions * opt_space,
247 						   struct ip6_flowlabel * fl,
248 						   struct ipv6_txoptions * fopt);
249 extern void			fl6_free_socklist(struct sock *sk);
250 extern int			ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen);
251 extern int			ip6_flowlabel_init(void);
252 extern void			ip6_flowlabel_cleanup(void);
253 
254 static inline void fl6_sock_release(struct ip6_flowlabel *fl)
255 {
256 	if (fl)
257 		atomic_dec(&fl->users);
258 }
259 
260 extern void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info);
261 
262 extern int 			ip6_ra_control(struct sock *sk, int sel);
263 
264 extern int			ipv6_parse_hopopts(struct sk_buff *skb);
265 
266 extern struct ipv6_txoptions *  ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt);
267 extern struct ipv6_txoptions *	ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
268 						   int newtype,
269 						   struct ipv6_opt_hdr __user *newopt,
270 						   int newoptlen);
271 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
272 					  struct ipv6_txoptions *opt);
273 
274 extern bool ipv6_opt_accepted(const struct sock *sk, const struct sk_buff *skb);
275 
276 static inline bool ipv6_accept_ra(struct inet6_dev *idev)
277 {
278 	/* If forwarding is enabled, RA are not accepted unless the special
279 	 * hybrid mode (accept_ra=2) is enabled.
280 	 */
281 	return idev->cnf.forwarding ? idev->cnf.accept_ra == 2 :
282 	    idev->cnf.accept_ra;
283 }
284 
285 #if IS_ENABLED(CONFIG_IPV6)
286 static inline int ip6_frag_nqueues(struct net *net)
287 {
288 	return net->ipv6.frags.nqueues;
289 }
290 
291 static inline int ip6_frag_mem(struct net *net)
292 {
293 	return sum_frag_mem_limit(&net->ipv6.frags);
294 }
295 #endif
296 
297 #define IPV6_FRAG_HIGH_THRESH	(4 * 1024*1024)	/* 4194304 */
298 #define IPV6_FRAG_LOW_THRESH	(3 * 1024*1024)	/* 3145728 */
299 #define IPV6_FRAG_TIMEOUT	(60 * HZ)	/* 60 seconds */
300 
301 extern int __ipv6_addr_type(const struct in6_addr *addr);
302 static inline int ipv6_addr_type(const struct in6_addr *addr)
303 {
304 	return __ipv6_addr_type(addr) & 0xffff;
305 }
306 
307 static inline int ipv6_addr_scope(const struct in6_addr *addr)
308 {
309 	return __ipv6_addr_type(addr) & IPV6_ADDR_SCOPE_MASK;
310 }
311 
312 static inline int __ipv6_addr_src_scope(int type)
313 {
314 	return (type == IPV6_ADDR_ANY) ? __IPV6_ADDR_SCOPE_INVALID : (type >> 16);
315 }
316 
317 static inline int ipv6_addr_src_scope(const struct in6_addr *addr)
318 {
319 	return __ipv6_addr_src_scope(__ipv6_addr_type(addr));
320 }
321 
322 static inline int ipv6_addr_cmp(const struct in6_addr *a1, const struct in6_addr *a2)
323 {
324 	return memcmp(a1, a2, sizeof(struct in6_addr));
325 }
326 
327 static inline bool
328 ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m,
329 		     const struct in6_addr *a2)
330 {
331 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
332 	const unsigned long *ul1 = (const unsigned long *)a1;
333 	const unsigned long *ulm = (const unsigned long *)m;
334 	const unsigned long *ul2 = (const unsigned long *)a2;
335 
336 	return !!(((ul1[0] ^ ul2[0]) & ulm[0]) |
337 		  ((ul1[1] ^ ul2[1]) & ulm[1]));
338 #else
339 	return !!(((a1->s6_addr32[0] ^ a2->s6_addr32[0]) & m->s6_addr32[0]) |
340 		  ((a1->s6_addr32[1] ^ a2->s6_addr32[1]) & m->s6_addr32[1]) |
341 		  ((a1->s6_addr32[2] ^ a2->s6_addr32[2]) & m->s6_addr32[2]) |
342 		  ((a1->s6_addr32[3] ^ a2->s6_addr32[3]) & m->s6_addr32[3]));
343 #endif
344 }
345 
346 static inline void ipv6_addr_prefix(struct in6_addr *pfx,
347 				    const struct in6_addr *addr,
348 				    int plen)
349 {
350 	/* caller must guarantee 0 <= plen <= 128 */
351 	int o = plen >> 3,
352 	    b = plen & 0x7;
353 
354 	memset(pfx->s6_addr, 0, sizeof(pfx->s6_addr));
355 	memcpy(pfx->s6_addr, addr, o);
356 	if (b != 0)
357 		pfx->s6_addr[o] = addr->s6_addr[o] & (0xff00 >> b);
358 }
359 
360 static inline void __ipv6_addr_set_half(__be32 *addr,
361 					__be32 wh, __be32 wl)
362 {
363 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
364 #if defined(__BIG_ENDIAN)
365 	if (__builtin_constant_p(wh) && __builtin_constant_p(wl)) {
366 		*(__force u64 *)addr = ((__force u64)(wh) << 32 | (__force u64)(wl));
367 		return;
368 	}
369 #elif defined(__LITTLE_ENDIAN)
370 	if (__builtin_constant_p(wl) && __builtin_constant_p(wh)) {
371 		*(__force u64 *)addr = ((__force u64)(wl) << 32 | (__force u64)(wh));
372 		return;
373 	}
374 #endif
375 #endif
376 	addr[0] = wh;
377 	addr[1] = wl;
378 }
379 
380 static inline void ipv6_addr_set(struct in6_addr *addr,
381 				     __be32 w1, __be32 w2,
382 				     __be32 w3, __be32 w4)
383 {
384 	__ipv6_addr_set_half(&addr->s6_addr32[0], w1, w2);
385 	__ipv6_addr_set_half(&addr->s6_addr32[2], w3, w4);
386 }
387 
388 static inline bool ipv6_addr_equal(const struct in6_addr *a1,
389 				   const struct in6_addr *a2)
390 {
391 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
392 	const unsigned long *ul1 = (const unsigned long *)a1;
393 	const unsigned long *ul2 = (const unsigned long *)a2;
394 
395 	return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL;
396 #else
397 	return ((a1->s6_addr32[0] ^ a2->s6_addr32[0]) |
398 		(a1->s6_addr32[1] ^ a2->s6_addr32[1]) |
399 		(a1->s6_addr32[2] ^ a2->s6_addr32[2]) |
400 		(a1->s6_addr32[3] ^ a2->s6_addr32[3])) == 0;
401 #endif
402 }
403 
404 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
405 static inline bool __ipv6_prefix_equal64_half(const __be64 *a1,
406 					      const __be64 *a2,
407 					      unsigned int len)
408 {
409 	if (len && ((*a1 ^ *a2) & cpu_to_be64((~0UL) << (64 - len))))
410 		return false;
411 	return true;
412 }
413 
414 static inline bool ipv6_prefix_equal(const struct in6_addr *addr1,
415 				     const struct in6_addr *addr2,
416 				     unsigned int prefixlen)
417 {
418 	const __be64 *a1 = (const __be64 *)addr1;
419 	const __be64 *a2 = (const __be64 *)addr2;
420 
421 	if (prefixlen >= 64) {
422 		if (a1[0] ^ a2[0])
423 			return false;
424 		return __ipv6_prefix_equal64_half(a1 + 1, a2 + 1, prefixlen - 64);
425 	}
426 	return __ipv6_prefix_equal64_half(a1, a2, prefixlen);
427 }
428 #else
429 static inline bool ipv6_prefix_equal(const struct in6_addr *addr1,
430 				     const struct in6_addr *addr2,
431 				     unsigned int prefixlen)
432 {
433 	const __be32 *a1 = addr1->s6_addr32;
434 	const __be32 *a2 = addr2->s6_addr32;
435 	unsigned int pdw, pbi;
436 
437 	/* check complete u32 in prefix */
438 	pdw = prefixlen >> 5;
439 	if (pdw && memcmp(a1, a2, pdw << 2))
440 		return false;
441 
442 	/* check incomplete u32 in prefix */
443 	pbi = prefixlen & 0x1f;
444 	if (pbi && ((a1[pdw] ^ a2[pdw]) & htonl((0xffffffff) << (32 - pbi))))
445 		return false;
446 
447 	return true;
448 }
449 #endif
450 
451 struct inet_frag_queue;
452 
453 enum ip6_defrag_users {
454 	IP6_DEFRAG_LOCAL_DELIVER,
455 	IP6_DEFRAG_CONNTRACK_IN,
456 	__IP6_DEFRAG_CONNTRACK_IN	= IP6_DEFRAG_CONNTRACK_IN + USHRT_MAX,
457 	IP6_DEFRAG_CONNTRACK_OUT,
458 	__IP6_DEFRAG_CONNTRACK_OUT	= IP6_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
459 	IP6_DEFRAG_CONNTRACK_BRIDGE_IN,
460 	__IP6_DEFRAG_CONNTRACK_BRIDGE_IN = IP6_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
461 };
462 
463 struct ip6_create_arg {
464 	__be32 id;
465 	u32 user;
466 	const struct in6_addr *src;
467 	const struct in6_addr *dst;
468 };
469 
470 void ip6_frag_init(struct inet_frag_queue *q, void *a);
471 bool ip6_frag_match(struct inet_frag_queue *q, void *a);
472 
473 /*
474  *	Equivalent of ipv4 struct ip
475  */
476 struct frag_queue {
477 	struct inet_frag_queue	q;
478 
479 	__be32			id;		/* fragment id		*/
480 	u32			user;
481 	struct in6_addr		saddr;
482 	struct in6_addr		daddr;
483 
484 	int			iif;
485 	unsigned int		csum;
486 	__u16			nhoffset;
487 };
488 
489 void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,
490 			   struct inet_frags *frags);
491 
492 static inline bool ipv6_addr_any(const struct in6_addr *a)
493 {
494 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
495 	const unsigned long *ul = (const unsigned long *)a;
496 
497 	return (ul[0] | ul[1]) == 0UL;
498 #else
499 	return (a->s6_addr32[0] | a->s6_addr32[1] |
500 		a->s6_addr32[2] | a->s6_addr32[3]) == 0;
501 #endif
502 }
503 
504 static inline u32 ipv6_addr_hash(const struct in6_addr *a)
505 {
506 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
507 	const unsigned long *ul = (const unsigned long *)a;
508 	unsigned long x = ul[0] ^ ul[1];
509 
510 	return (u32)(x ^ (x >> 32));
511 #else
512 	return (__force u32)(a->s6_addr32[0] ^ a->s6_addr32[1] ^
513 			     a->s6_addr32[2] ^ a->s6_addr32[3]);
514 #endif
515 }
516 
517 static inline bool ipv6_addr_loopback(const struct in6_addr *a)
518 {
519 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
520 	const unsigned long *ul = (const unsigned long *)a;
521 
522 	return (ul[0] | (ul[1] ^ cpu_to_be64(1))) == 0UL;
523 #else
524 	return (a->s6_addr32[0] | a->s6_addr32[1] |
525 		a->s6_addr32[2] | (a->s6_addr32[3] ^ htonl(1))) == 0;
526 #endif
527 }
528 
529 static inline bool ipv6_addr_v4mapped(const struct in6_addr *a)
530 {
531 	return (
532 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
533 		*(__be64 *)a |
534 #else
535 		(a->s6_addr32[0] | a->s6_addr32[1]) |
536 #endif
537 		(a->s6_addr32[2] ^ htonl(0x0000ffff))) == 0UL;
538 }
539 
540 /*
541  * Check for a RFC 4843 ORCHID address
542  * (Overlay Routable Cryptographic Hash Identifiers)
543  */
544 static inline bool ipv6_addr_orchid(const struct in6_addr *a)
545 {
546 	return (a->s6_addr32[0] & htonl(0xfffffff0)) == htonl(0x20010010);
547 }
548 
549 static inline void ipv6_addr_set_v4mapped(const __be32 addr,
550 					  struct in6_addr *v4mapped)
551 {
552 	ipv6_addr_set(v4mapped,
553 			0, 0,
554 			htonl(0x0000FFFF),
555 			addr);
556 }
557 
558 /*
559  * find the first different bit between two addresses
560  * length of address must be a multiple of 32bits
561  */
562 static inline int __ipv6_addr_diff32(const void *token1, const void *token2, int addrlen)
563 {
564 	const __be32 *a1 = token1, *a2 = token2;
565 	int i;
566 
567 	addrlen >>= 2;
568 
569 	for (i = 0; i < addrlen; i++) {
570 		__be32 xb = a1[i] ^ a2[i];
571 		if (xb)
572 			return i * 32 + 31 - __fls(ntohl(xb));
573 	}
574 
575 	/*
576 	 *	we should *never* get to this point since that
577 	 *	would mean the addrs are equal
578 	 *
579 	 *	However, we do get to it 8) And exacly, when
580 	 *	addresses are equal 8)
581 	 *
582 	 *	ip route add 1111::/128 via ...
583 	 *	ip route add 1111::/64 via ...
584 	 *	and we are here.
585 	 *
586 	 *	Ideally, this function should stop comparison
587 	 *	at prefix length. It does not, but it is still OK,
588 	 *	if returned value is greater than prefix length.
589 	 *					--ANK (980803)
590 	 */
591 	return addrlen << 5;
592 }
593 
594 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
595 static inline int __ipv6_addr_diff64(const void *token1, const void *token2, int addrlen)
596 {
597 	const __be64 *a1 = token1, *a2 = token2;
598 	int i;
599 
600 	addrlen >>= 3;
601 
602 	for (i = 0; i < addrlen; i++) {
603 		__be64 xb = a1[i] ^ a2[i];
604 		if (xb)
605 			return i * 64 + 63 - __fls(be64_to_cpu(xb));
606 	}
607 
608 	return addrlen << 6;
609 }
610 #endif
611 
612 static inline int __ipv6_addr_diff(const void *token1, const void *token2, int addrlen)
613 {
614 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
615 	if (__builtin_constant_p(addrlen) && !(addrlen & 7))
616 		return __ipv6_addr_diff64(token1, token2, addrlen);
617 #endif
618 	return __ipv6_addr_diff32(token1, token2, addrlen);
619 }
620 
621 static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_addr *a2)
622 {
623 	return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr));
624 }
625 
626 extern void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt);
627 
628 /*
629  *	Header manipulation
630  */
631 static inline void ip6_flow_hdr(struct ipv6hdr *hdr, unsigned int tclass,
632 				__be32 flowlabel)
633 {
634 	*(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | flowlabel;
635 }
636 
637 static inline __be32 ip6_flowinfo(const struct ipv6hdr *hdr)
638 {
639 	return *(__be32 *)hdr & IPV6_FLOWINFO_MASK;
640 }
641 
642 /*
643  *	Prototypes exported by ipv6
644  */
645 
646 /*
647  *	rcv function (called from netdevice level)
648  */
649 
650 extern int			ipv6_rcv(struct sk_buff *skb,
651 					 struct net_device *dev,
652 					 struct packet_type *pt,
653 					 struct net_device *orig_dev);
654 
655 extern int			ip6_rcv_finish(struct sk_buff *skb);
656 
657 /*
658  *	upper-layer output functions
659  */
660 extern int			ip6_xmit(struct sock *sk,
661 					 struct sk_buff *skb,
662 					 struct flowi6 *fl6,
663 					 struct ipv6_txoptions *opt,
664 					 int tclass);
665 
666 extern int			ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr);
667 
668 extern int			ip6_append_data(struct sock *sk,
669 						int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb),
670 		    				void *from,
671 						int length,
672 						int transhdrlen,
673 		      				int hlimit,
674 		      				int tclass,
675 						struct ipv6_txoptions *opt,
676 						struct flowi6 *fl6,
677 						struct rt6_info *rt,
678 						unsigned int flags,
679 						int dontfrag);
680 
681 extern int			ip6_push_pending_frames(struct sock *sk);
682 
683 extern void			ip6_flush_pending_frames(struct sock *sk);
684 
685 extern int			ip6_dst_lookup(struct sock *sk,
686 					       struct dst_entry **dst,
687 					       struct flowi6 *fl6);
688 extern struct dst_entry *	ip6_dst_lookup_flow(struct sock *sk,
689 						    struct flowi6 *fl6,
690 						    const struct in6_addr *final_dst,
691 						    bool can_sleep);
692 extern struct dst_entry *	ip6_sk_dst_lookup_flow(struct sock *sk,
693 						       struct flowi6 *fl6,
694 						       const struct in6_addr *final_dst,
695 						       bool can_sleep);
696 extern struct dst_entry *	ip6_blackhole_route(struct net *net,
697 						    struct dst_entry *orig_dst);
698 
699 /*
700  *	skb processing functions
701  */
702 
703 extern int			ip6_output(struct sk_buff *skb);
704 extern int			ip6_forward(struct sk_buff *skb);
705 extern int			ip6_input(struct sk_buff *skb);
706 extern int			ip6_mc_input(struct sk_buff *skb);
707 
708 extern int			__ip6_local_out(struct sk_buff *skb);
709 extern int			ip6_local_out(struct sk_buff *skb);
710 
711 /*
712  *	Extension header (options) processing
713  */
714 
715 extern void 			ipv6_push_nfrag_opts(struct sk_buff *skb,
716 						     struct ipv6_txoptions *opt,
717 						     u8 *proto,
718 						     struct in6_addr **daddr_p);
719 extern void			ipv6_push_frag_opts(struct sk_buff *skb,
720 						    struct ipv6_txoptions *opt,
721 						    u8 *proto);
722 
723 extern int			ipv6_skip_exthdr(const struct sk_buff *, int start,
724 					         u8 *nexthdrp, __be16 *frag_offp);
725 
726 extern bool			ipv6_ext_hdr(u8 nexthdr);
727 
728 enum {
729 	IP6_FH_F_FRAG		= (1 << 0),
730 	IP6_FH_F_AUTH		= (1 << 1),
731 	IP6_FH_F_SKIP_RH	= (1 << 2),
732 };
733 
734 /* find specified header and get offset to it */
735 extern int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
736 			 int target, unsigned short *fragoff, int *fragflg);
737 
738 extern int ipv6_find_tlv(struct sk_buff *skb, int offset, int type);
739 
740 extern struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
741 				       const struct ipv6_txoptions *opt,
742 				       struct in6_addr *orig);
743 
744 /*
745  *	socket options (ipv6_sockglue.c)
746  */
747 
748 extern int			ipv6_setsockopt(struct sock *sk, int level,
749 						int optname,
750 						char __user *optval,
751 						unsigned int optlen);
752 extern int			ipv6_getsockopt(struct sock *sk, int level,
753 						int optname,
754 						char __user *optval,
755 						int __user *optlen);
756 extern int			compat_ipv6_setsockopt(struct sock *sk,
757 						int level,
758 						int optname,
759 						char __user *optval,
760 						unsigned int optlen);
761 extern int			compat_ipv6_getsockopt(struct sock *sk,
762 						int level,
763 						int optname,
764 						char __user *optval,
765 						int __user *optlen);
766 
767 extern int			ip6_datagram_connect(struct sock *sk,
768 						     struct sockaddr *addr, int addr_len);
769 
770 extern int 			ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len);
771 extern int 			ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len);
772 extern void			ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
773 						u32 info, u8 *payload);
774 extern void			ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info);
775 extern void			ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu);
776 
777 extern int inet6_release(struct socket *sock);
778 extern int inet6_bind(struct socket *sock, struct sockaddr *uaddr,
779 		      int addr_len);
780 extern int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
781 			 int *uaddr_len, int peer);
782 extern int inet6_ioctl(struct socket *sock, unsigned int cmd,
783 		       unsigned long arg);
784 
785 extern int inet6_hash_connect(struct inet_timewait_death_row *death_row,
786 			      struct sock *sk);
787 
788 /*
789  * reassembly.c
790  */
791 extern const struct proto_ops inet6_stream_ops;
792 extern const struct proto_ops inet6_dgram_ops;
793 
794 struct group_source_req;
795 struct group_filter;
796 
797 extern int ip6_mc_source(int add, int omode, struct sock *sk,
798 			 struct group_source_req *pgsr);
799 extern int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf);
800 extern int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
801 			 struct group_filter __user *optval,
802 			 int __user *optlen);
803 extern unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
804 				    const struct in6_addr *daddr, u32 rnd);
805 
806 #ifdef CONFIG_PROC_FS
807 extern int  ac6_proc_init(struct net *net);
808 extern void ac6_proc_exit(struct net *net);
809 extern int  raw6_proc_init(void);
810 extern void raw6_proc_exit(void);
811 extern int  tcp6_proc_init(struct net *net);
812 extern void tcp6_proc_exit(struct net *net);
813 extern int  udp6_proc_init(struct net *net);
814 extern void udp6_proc_exit(struct net *net);
815 extern int  udplite6_proc_init(void);
816 extern void udplite6_proc_exit(void);
817 extern int  ipv6_misc_proc_init(void);
818 extern void ipv6_misc_proc_exit(void);
819 extern int snmp6_register_dev(struct inet6_dev *idev);
820 extern int snmp6_unregister_dev(struct inet6_dev *idev);
821 
822 #else
823 static inline int ac6_proc_init(struct net *net) { return 0; }
824 static inline void ac6_proc_exit(struct net *net) { }
825 static inline int snmp6_register_dev(struct inet6_dev *idev) { return 0; }
826 static inline int snmp6_unregister_dev(struct inet6_dev *idev) { return 0; }
827 #endif
828 
829 #ifdef CONFIG_SYSCTL
830 extern ctl_table ipv6_route_table_template[];
831 extern ctl_table ipv6_icmp_table_template[];
832 
833 extern struct ctl_table *ipv6_icmp_sysctl_init(struct net *net);
834 extern struct ctl_table *ipv6_route_sysctl_init(struct net *net);
835 extern int ipv6_sysctl_register(void);
836 extern void ipv6_sysctl_unregister(void);
837 #endif
838 
839 #endif /* _NET_IPV6_H */
840