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_ESP 50 /* Encapsulating security payload. */ 38 #define NEXTHDR_AUTH 51 /* Authentication header. */ 39 #define NEXTHDR_ICMP 58 /* ICMP for IPv6. */ 40 #define NEXTHDR_NONE 59 /* No next header */ 41 #define NEXTHDR_DEST 60 /* Destination options header. */ 42 #define NEXTHDR_MOBILITY 135 /* Mobility header. */ 43 44 #define NEXTHDR_MAX 255 45 46 47 48 #define IPV6_DEFAULT_HOPLIMIT 64 49 #define IPV6_DEFAULT_MCASTHOPS 1 50 51 /* 52 * Addr type 53 * 54 * type - unicast | multicast 55 * scope - local | site | global 56 * v4 - compat 57 * v4mapped 58 * any 59 * loopback 60 */ 61 62 #define IPV6_ADDR_ANY 0x0000U 63 64 #define IPV6_ADDR_UNICAST 0x0001U 65 #define IPV6_ADDR_MULTICAST 0x0002U 66 67 #define IPV6_ADDR_LOOPBACK 0x0010U 68 #define IPV6_ADDR_LINKLOCAL 0x0020U 69 #define IPV6_ADDR_SITELOCAL 0x0040U 70 71 #define IPV6_ADDR_COMPATv4 0x0080U 72 73 #define IPV6_ADDR_SCOPE_MASK 0x00f0U 74 75 #define IPV6_ADDR_MAPPED 0x1000U 76 #define IPV6_ADDR_RESERVED 0x2000U /* reserved address space */ 77 78 /* 79 * Addr scopes 80 */ 81 #ifdef __KERNEL__ 82 #define IPV6_ADDR_MC_SCOPE(a) \ 83 ((a)->s6_addr[1] & 0x0f) /* nonstandard */ 84 #define __IPV6_ADDR_SCOPE_INVALID -1 85 #endif 86 #define IPV6_ADDR_SCOPE_NODELOCAL 0x01 87 #define IPV6_ADDR_SCOPE_LINKLOCAL 0x02 88 #define IPV6_ADDR_SCOPE_SITELOCAL 0x05 89 #define IPV6_ADDR_SCOPE_ORGLOCAL 0x08 90 #define IPV6_ADDR_SCOPE_GLOBAL 0x0e 91 92 /* 93 * fragmentation header 94 */ 95 96 struct frag_hdr { 97 __u8 nexthdr; 98 __u8 reserved; 99 __be16 frag_off; 100 __be32 identification; 101 }; 102 103 #define IP6_MF 0x0001 104 105 #ifdef __KERNEL__ 106 107 #include <net/sock.h> 108 109 /* sysctls */ 110 extern int sysctl_mld_max_msf; 111 extern struct ctl_path net_ipv6_ctl_path[]; 112 113 #define _DEVINC(net, statname, modifier, idev, field) \ 114 ({ \ 115 struct inet6_dev *_idev = (idev); \ 116 if (likely(_idev != NULL)) \ 117 SNMP_INC_STATS##modifier((_idev)->stats.statname, (field)); \ 118 SNMP_INC_STATS##modifier((net)->mib.statname##_statistics, (field));\ 119 }) 120 121 #define _DEVADD(net, statname, modifier, idev, field, val) \ 122 ({ \ 123 struct inet6_dev *_idev = (idev); \ 124 if (likely(_idev != NULL)) \ 125 SNMP_ADD_STATS##modifier((_idev)->stats.statname, (field), (val)); \ 126 SNMP_ADD_STATS##modifier((net)->mib.statname##_statistics, (field), (val));\ 127 }) 128 129 #define _DEVUPD(net, statname, modifier, idev, field, val) \ 130 ({ \ 131 struct inet6_dev *_idev = (idev); \ 132 if (likely(_idev != NULL)) \ 133 SNMP_UPD_PO_STATS##modifier((_idev)->stats.statname, field, (val)); \ 134 SNMP_UPD_PO_STATS##modifier((net)->mib.statname##_statistics, field, (val));\ 135 }) 136 137 /* MIBs */ 138 139 #define IP6_INC_STATS(net, idev,field) \ 140 _DEVINC(net, ipv6, , idev, field) 141 #define IP6_INC_STATS_BH(net, idev,field) \ 142 _DEVINC(net, ipv6, _BH, idev, field) 143 #define IP6_ADD_STATS(net, idev,field,val) \ 144 _DEVADD(net, ipv6, , idev, field, val) 145 #define IP6_ADD_STATS_BH(net, idev,field,val) \ 146 _DEVADD(net, ipv6, _BH, idev, field, val) 147 #define IP6_UPD_PO_STATS(net, idev,field,val) \ 148 _DEVUPD(net, ipv6, , idev, field, val) 149 #define IP6_UPD_PO_STATS_BH(net, idev,field,val) \ 150 _DEVUPD(net, ipv6, _BH, idev, field, val) 151 #define ICMP6_INC_STATS(net, idev, field) \ 152 _DEVINC(net, icmpv6, , idev, field) 153 #define ICMP6_INC_STATS_BH(net, idev, field) \ 154 _DEVINC(net, icmpv6, _BH, idev, field) 155 156 #define ICMP6MSGOUT_INC_STATS(net, idev, field) \ 157 _DEVINC(net, icmpv6msg, , idev, field +256) 158 #define ICMP6MSGOUT_INC_STATS_BH(net, idev, field) \ 159 _DEVINC(net, icmpv6msg, _BH, idev, field +256) 160 #define ICMP6MSGIN_INC_STATS_BH(net, idev, field) \ 161 _DEVINC(net, icmpv6msg, _BH, idev, field) 162 163 struct ip6_ra_chain { 164 struct ip6_ra_chain *next; 165 struct sock *sk; 166 int sel; 167 void (*destructor)(struct sock *); 168 }; 169 170 extern struct ip6_ra_chain *ip6_ra_chain; 171 extern rwlock_t ip6_ra_lock; 172 173 /* 174 This structure is prepared by protocol, when parsing 175 ancillary data and passed to IPv6. 176 */ 177 178 struct ipv6_txoptions { 179 /* Length of this structure */ 180 int tot_len; 181 182 /* length of extension headers */ 183 184 __u16 opt_flen; /* after fragment hdr */ 185 __u16 opt_nflen; /* before fragment hdr */ 186 187 struct ipv6_opt_hdr *hopopt; 188 struct ipv6_opt_hdr *dst0opt; 189 struct ipv6_rt_hdr *srcrt; /* Routing Header */ 190 struct ipv6_opt_hdr *dst1opt; 191 192 /* Option buffer, as read by IPV6_PKTOPTIONS, starts here. */ 193 }; 194 195 struct ip6_flowlabel { 196 struct ip6_flowlabel *next; 197 __be32 label; 198 atomic_t users; 199 struct in6_addr dst; 200 struct ipv6_txoptions *opt; 201 unsigned long linger; 202 u8 share; 203 u32 owner; 204 unsigned long lastuse; 205 unsigned long expires; 206 struct net *fl_net; 207 }; 208 209 #define IPV6_FLOWINFO_MASK cpu_to_be32(0x0FFFFFFF) 210 #define IPV6_FLOWLABEL_MASK cpu_to_be32(0x000FFFFF) 211 212 struct ipv6_fl_socklist { 213 struct ipv6_fl_socklist *next; 214 struct ip6_flowlabel *fl; 215 }; 216 217 extern struct ip6_flowlabel *fl6_sock_lookup(struct sock *sk, __be32 label); 218 extern struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space, 219 struct ip6_flowlabel * fl, 220 struct ipv6_txoptions * fopt); 221 extern void fl6_free_socklist(struct sock *sk); 222 extern int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen); 223 extern int ip6_flowlabel_init(void); 224 extern void ip6_flowlabel_cleanup(void); 225 226 static inline void fl6_sock_release(struct ip6_flowlabel *fl) 227 { 228 if (fl) 229 atomic_dec(&fl->users); 230 } 231 232 extern int ip6_ra_control(struct sock *sk, int sel); 233 234 extern int ipv6_parse_hopopts(struct sk_buff *skb); 235 236 extern struct ipv6_txoptions * ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt); 237 extern struct ipv6_txoptions * ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 238 int newtype, 239 struct ipv6_opt_hdr __user *newopt, 240 int newoptlen); 241 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 242 struct ipv6_txoptions *opt); 243 244 extern int ipv6_opt_accepted(struct sock *sk, struct sk_buff *skb); 245 246 int ip6_frag_nqueues(struct net *net); 247 int ip6_frag_mem(struct net *net); 248 249 #define IPV6_FRAG_TIMEOUT (60*HZ) /* 60 seconds */ 250 251 extern int __ipv6_addr_type(const struct in6_addr *addr); 252 static inline int ipv6_addr_type(const struct in6_addr *addr) 253 { 254 return __ipv6_addr_type(addr) & 0xffff; 255 } 256 257 static inline int ipv6_addr_scope(const struct in6_addr *addr) 258 { 259 return __ipv6_addr_type(addr) & IPV6_ADDR_SCOPE_MASK; 260 } 261 262 static inline int __ipv6_addr_src_scope(int type) 263 { 264 return (type == IPV6_ADDR_ANY ? __IPV6_ADDR_SCOPE_INVALID : (type >> 16)); 265 } 266 267 static inline int ipv6_addr_src_scope(const struct in6_addr *addr) 268 { 269 return __ipv6_addr_src_scope(__ipv6_addr_type(addr)); 270 } 271 272 static inline int ipv6_addr_cmp(const struct in6_addr *a1, const struct in6_addr *a2) 273 { 274 return memcmp(a1, a2, sizeof(struct in6_addr)); 275 } 276 277 static inline int 278 ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m, 279 const struct in6_addr *a2) 280 { 281 return (!!(((a1->s6_addr32[0] ^ a2->s6_addr32[0]) & m->s6_addr32[0]) | 282 ((a1->s6_addr32[1] ^ a2->s6_addr32[1]) & m->s6_addr32[1]) | 283 ((a1->s6_addr32[2] ^ a2->s6_addr32[2]) & m->s6_addr32[2]) | 284 ((a1->s6_addr32[3] ^ a2->s6_addr32[3]) & m->s6_addr32[3]))); 285 } 286 287 static inline void ipv6_addr_copy(struct in6_addr *a1, const struct in6_addr *a2) 288 { 289 memcpy(a1, a2, sizeof(struct in6_addr)); 290 } 291 292 static inline void ipv6_addr_prefix(struct in6_addr *pfx, 293 const struct in6_addr *addr, 294 int plen) 295 { 296 /* caller must guarantee 0 <= plen <= 128 */ 297 int o = plen >> 3, 298 b = plen & 0x7; 299 300 memset(pfx->s6_addr, 0, sizeof(pfx->s6_addr)); 301 memcpy(pfx->s6_addr, addr, o); 302 if (b != 0) 303 pfx->s6_addr[o] = addr->s6_addr[o] & (0xff00 >> b); 304 } 305 306 static inline void ipv6_addr_set(struct in6_addr *addr, 307 __be32 w1, __be32 w2, 308 __be32 w3, __be32 w4) 309 { 310 addr->s6_addr32[0] = w1; 311 addr->s6_addr32[1] = w2; 312 addr->s6_addr32[2] = w3; 313 addr->s6_addr32[3] = w4; 314 } 315 316 static inline int ipv6_addr_equal(const struct in6_addr *a1, 317 const struct in6_addr *a2) 318 { 319 return (((a1->s6_addr32[0] ^ a2->s6_addr32[0]) | 320 (a1->s6_addr32[1] ^ a2->s6_addr32[1]) | 321 (a1->s6_addr32[2] ^ a2->s6_addr32[2]) | 322 (a1->s6_addr32[3] ^ a2->s6_addr32[3])) == 0); 323 } 324 325 static inline int __ipv6_prefix_equal(const __be32 *a1, const __be32 *a2, 326 unsigned int prefixlen) 327 { 328 unsigned pdw, pbi; 329 330 /* check complete u32 in prefix */ 331 pdw = prefixlen >> 5; 332 if (pdw && memcmp(a1, a2, pdw << 2)) 333 return 0; 334 335 /* check incomplete u32 in prefix */ 336 pbi = prefixlen & 0x1f; 337 if (pbi && ((a1[pdw] ^ a2[pdw]) & htonl((0xffffffff) << (32 - pbi)))) 338 return 0; 339 340 return 1; 341 } 342 343 static inline int ipv6_prefix_equal(const struct in6_addr *a1, 344 const struct in6_addr *a2, 345 unsigned int prefixlen) 346 { 347 return __ipv6_prefix_equal(a1->s6_addr32, a2->s6_addr32, 348 prefixlen); 349 } 350 351 struct inet_frag_queue; 352 353 struct ip6_create_arg { 354 __be32 id; 355 struct in6_addr *src; 356 struct in6_addr *dst; 357 }; 358 359 void ip6_frag_init(struct inet_frag_queue *q, void *a); 360 int ip6_frag_match(struct inet_frag_queue *q, void *a); 361 362 static inline int ipv6_addr_any(const struct in6_addr *a) 363 { 364 return ((a->s6_addr32[0] | a->s6_addr32[1] | 365 a->s6_addr32[2] | a->s6_addr32[3] ) == 0); 366 } 367 368 static inline int ipv6_addr_loopback(const struct in6_addr *a) 369 { 370 return ((a->s6_addr32[0] | a->s6_addr32[1] | 371 a->s6_addr32[2] | (a->s6_addr32[3] ^ htonl(1))) == 0); 372 } 373 374 static inline int ipv6_addr_v4mapped(const struct in6_addr *a) 375 { 376 return ((a->s6_addr32[0] | a->s6_addr32[1] | 377 (a->s6_addr32[2] ^ htonl(0x0000ffff))) == 0); 378 } 379 380 /* 381 * Check for a RFC 4843 ORCHID address 382 * (Overlay Routable Cryptographic Hash Identifiers) 383 */ 384 static inline int ipv6_addr_orchid(const struct in6_addr *a) 385 { 386 return ((a->s6_addr32[0] & htonl(0xfffffff0)) 387 == htonl(0x20010010)); 388 } 389 390 static inline void ipv6_addr_set_v4mapped(const __be32 addr, 391 struct in6_addr *v4mapped) 392 { 393 ipv6_addr_set(v4mapped, 394 0, 0, 395 htonl(0x0000FFFF), 396 addr); 397 } 398 399 /* 400 * find the first different bit between two addresses 401 * length of address must be a multiple of 32bits 402 */ 403 static inline int __ipv6_addr_diff(const void *token1, const void *token2, int addrlen) 404 { 405 const __be32 *a1 = token1, *a2 = token2; 406 int i; 407 408 addrlen >>= 2; 409 410 for (i = 0; i < addrlen; i++) { 411 __be32 xb = a1[i] ^ a2[i]; 412 if (xb) 413 return i * 32 + 32 - fls(ntohl(xb)); 414 } 415 416 /* 417 * we should *never* get to this point since that 418 * would mean the addrs are equal 419 * 420 * However, we do get to it 8) And exacly, when 421 * addresses are equal 8) 422 * 423 * ip route add 1111::/128 via ... 424 * ip route add 1111::/64 via ... 425 * and we are here. 426 * 427 * Ideally, this function should stop comparison 428 * at prefix length. It does not, but it is still OK, 429 * if returned value is greater than prefix length. 430 * --ANK (980803) 431 */ 432 return (addrlen << 5); 433 } 434 435 static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_addr *a2) 436 { 437 return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr)); 438 } 439 440 static __inline__ void ipv6_select_ident(struct frag_hdr *fhdr) 441 { 442 static u32 ipv6_fragmentation_id = 1; 443 static DEFINE_SPINLOCK(ip6_id_lock); 444 445 spin_lock_bh(&ip6_id_lock); 446 fhdr->identification = htonl(ipv6_fragmentation_id); 447 if (++ipv6_fragmentation_id == 0) 448 ipv6_fragmentation_id = 1; 449 spin_unlock_bh(&ip6_id_lock); 450 } 451 452 /* 453 * Prototypes exported by ipv6 454 */ 455 456 /* 457 * rcv function (called from netdevice level) 458 */ 459 460 extern int ipv6_rcv(struct sk_buff *skb, 461 struct net_device *dev, 462 struct packet_type *pt, 463 struct net_device *orig_dev); 464 465 extern int ip6_rcv_finish(struct sk_buff *skb); 466 467 /* 468 * upper-layer output functions 469 */ 470 extern int ip6_xmit(struct sock *sk, 471 struct sk_buff *skb, 472 struct flowi *fl, 473 struct ipv6_txoptions *opt, 474 int ipfragok); 475 476 extern int ip6_nd_hdr(struct sock *sk, 477 struct sk_buff *skb, 478 struct net_device *dev, 479 const struct in6_addr *saddr, 480 const struct in6_addr *daddr, 481 int proto, int len); 482 483 extern int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr); 484 485 extern int ip6_append_data(struct sock *sk, 486 int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), 487 void *from, 488 int length, 489 int transhdrlen, 490 int hlimit, 491 int tclass, 492 struct ipv6_txoptions *opt, 493 struct flowi *fl, 494 struct rt6_info *rt, 495 unsigned int flags); 496 497 extern int ip6_push_pending_frames(struct sock *sk); 498 499 extern void ip6_flush_pending_frames(struct sock *sk); 500 501 extern int ip6_dst_lookup(struct sock *sk, 502 struct dst_entry **dst, 503 struct flowi *fl); 504 extern int ip6_dst_blackhole(struct sock *sk, 505 struct dst_entry **dst, 506 struct flowi *fl); 507 extern int ip6_sk_dst_lookup(struct sock *sk, 508 struct dst_entry **dst, 509 struct flowi *fl); 510 511 /* 512 * skb processing functions 513 */ 514 515 extern int ip6_output(struct sk_buff *skb); 516 extern int ip6_forward(struct sk_buff *skb); 517 extern int ip6_input(struct sk_buff *skb); 518 extern int ip6_mc_input(struct sk_buff *skb); 519 520 extern int __ip6_local_out(struct sk_buff *skb); 521 extern int ip6_local_out(struct sk_buff *skb); 522 523 /* 524 * Extension header (options) processing 525 */ 526 527 extern void ipv6_push_nfrag_opts(struct sk_buff *skb, 528 struct ipv6_txoptions *opt, 529 u8 *proto, 530 struct in6_addr **daddr_p); 531 extern void ipv6_push_frag_opts(struct sk_buff *skb, 532 struct ipv6_txoptions *opt, 533 u8 *proto); 534 535 extern int ipv6_skip_exthdr(const struct sk_buff *, int start, 536 u8 *nexthdrp); 537 538 extern int ipv6_ext_hdr(u8 nexthdr); 539 540 extern int ipv6_find_tlv(struct sk_buff *skb, int offset, int type); 541 542 /* 543 * socket options (ipv6_sockglue.c) 544 */ 545 546 extern int ipv6_setsockopt(struct sock *sk, int level, 547 int optname, 548 char __user *optval, 549 unsigned int optlen); 550 extern int ipv6_getsockopt(struct sock *sk, int level, 551 int optname, 552 char __user *optval, 553 int __user *optlen); 554 extern int compat_ipv6_setsockopt(struct sock *sk, 555 int level, 556 int optname, 557 char __user *optval, 558 unsigned int optlen); 559 extern int compat_ipv6_getsockopt(struct sock *sk, 560 int level, 561 int optname, 562 char __user *optval, 563 int __user *optlen); 564 565 extern int ip6_datagram_connect(struct sock *sk, 566 struct sockaddr *addr, int addr_len); 567 568 extern int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len); 569 extern void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port, 570 u32 info, u8 *payload); 571 extern void ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info); 572 573 extern int inet6_release(struct socket *sock); 574 extern int inet6_bind(struct socket *sock, struct sockaddr *uaddr, 575 int addr_len); 576 extern int inet6_getname(struct socket *sock, struct sockaddr *uaddr, 577 int *uaddr_len, int peer); 578 extern int inet6_ioctl(struct socket *sock, unsigned int cmd, 579 unsigned long arg); 580 581 extern int inet6_hash_connect(struct inet_timewait_death_row *death_row, 582 struct sock *sk); 583 584 /* 585 * reassembly.c 586 */ 587 extern const struct proto_ops inet6_stream_ops; 588 extern const struct proto_ops inet6_dgram_ops; 589 590 struct group_source_req; 591 struct group_filter; 592 593 extern int ip6_mc_source(int add, int omode, struct sock *sk, 594 struct group_source_req *pgsr); 595 extern int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf); 596 extern int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf, 597 struct group_filter __user *optval, 598 int __user *optlen); 599 extern unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr, 600 const struct in6_addr *daddr, u32 rnd); 601 602 #ifdef CONFIG_PROC_FS 603 extern int ac6_proc_init(struct net *net); 604 extern void ac6_proc_exit(struct net *net); 605 extern int raw6_proc_init(void); 606 extern void raw6_proc_exit(void); 607 extern int tcp6_proc_init(struct net *net); 608 extern void tcp6_proc_exit(struct net *net); 609 extern int udp6_proc_init(struct net *net); 610 extern void udp6_proc_exit(struct net *net); 611 extern int udplite6_proc_init(void); 612 extern void udplite6_proc_exit(void); 613 extern int ipv6_misc_proc_init(void); 614 extern void ipv6_misc_proc_exit(void); 615 extern int snmp6_register_dev(struct inet6_dev *idev); 616 extern int snmp6_unregister_dev(struct inet6_dev *idev); 617 618 #else 619 static inline int ac6_proc_init(struct net *net) { return 0; } 620 static inline void ac6_proc_exit(struct net *net) { } 621 static inline int snmp6_register_dev(struct inet6_dev *idev) { return 0; } 622 static inline int snmp6_unregister_dev(struct inet6_dev *idev) { return 0; } 623 #endif 624 625 #ifdef CONFIG_SYSCTL 626 extern ctl_table ipv6_route_table_template[]; 627 extern ctl_table ipv6_icmp_table_template[]; 628 629 extern struct ctl_table *ipv6_icmp_sysctl_init(struct net *net); 630 extern struct ctl_table *ipv6_route_sysctl_init(struct net *net); 631 extern int ipv6_sysctl_register(void); 632 extern void ipv6_sysctl_unregister(void); 633 extern int ipv6_static_sysctl_register(void); 634 extern void ipv6_static_sysctl_unregister(void); 635 #endif 636 637 #endif /* __KERNEL__ */ 638 #endif /* _NET_IPV6_H */ 639