lib/zebra.h

   1 /* Zebra common header.
   2    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Kunihiro Ishiguro
   3
   4 This file is part of GNU Zebra.
   5
   6 GNU Zebra is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 2, or (at your option) any
   9 later version.
  10
  11 GNU Zebra is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Zebra; see the file COPYING.  If not, write to the Free
  18 Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #ifndef _ZEBRA_H
  22 #define _ZEBRA_H
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include "config.h"
  26 #endif /* HAVE_CONFIG_H */
  27
  28 #ifdef SUNOS_5
  29 #define _XPG4_2
  30 #define __EXTENSIONS__
  31 typedef unsigned int    u_int32_t;
  32 typedef unsigned short  u_int16_t;
  33 typedef unsigned char   u_int8_t;
  34 #endif /* SUNOS_5 */
  35
  36 #ifndef HAVE_SOCKLEN_T
  37 typedef int socklen_t;
  38 #endif /* HAVE_SOCKLEN_T */
  39
  40 #include <unistd.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <ctype.h>
  44 #include <errno.h>
  45 #include <fcntl.h>
  46 #include <signal.h>
  47 #include <string.h>
  48 #include <pwd.h>
  49 #include <grp.h>
  50 #ifdef HAVE_STROPTS_H
  51 #include <stropts.h>
  52 #endif /* HAVE_STROPTS_H */
  53 #include <sys/fcntl.h>
  54 #ifdef HAVE_SYS_SELECT_H
  55 #include <sys/select.h>
  56 #endif /* HAVE_SYS_SELECT_H */
  57 #include <sys/stat.h>
  58 #include <sys/types.h>
  59 #include <sys/param.h>
  60 #ifdef HAVE_SYS_SYSCTL_H
  61 #ifdef GNU_LINUX
  62 #include <linux/types.h>
  63 #endif
  64 #include <sys/sysctl.h>
  65 #endif /* HAVE_SYS_SYSCTL_H */
  66 #include <sys/ioctl.h>
  67 #ifdef HAVE_SYS_CONF_H
  68 #include <sys/conf.h>
  69 #endif /* HAVE_SYS_CONF_H */
  70 #ifdef HAVE_SYS_KSYM_H
  71 #include <sys/ksym.h>
  72 #endif /* HAVE_SYS_KSYM_H */
  73 #include <syslog.h>
  74 #ifdef TIME_WITH_SYS_TIME
  75 # include <sys/time.h>
  76 # include <time.h>
  77 #else
  78 # ifdef HAVE_SYS_TIME_H
  79 #  include <sys/time.h>
  80 # else
  81 #  include <time.h>
  82 # endif
  83 #endif /* TIME_WITH_SYS_TIME */
  84 #include <sys/uio.h>
  85 #include <sys/utsname.h>
  86 #ifdef HAVE_RUSAGE
  87 #include <sys/resource.h>
  88 #endif /* HAVE_RUSAGE */
  89 #ifdef HAVE_LIMITS_H
  90 #include <limits.h>
  91 #endif /* HAVE_LIMITS_H */
  92 #ifdef HAVE_INTTYPES_H
  93 #include <inttypes.h>
  94 #endif /* HAVE_INTTYPES_H */
  95
  96 /* machine dependent includes */
  97 #ifdef SUNOS_5
  98 #include <strings.h>
  99 #endif /* SUNOS_5 */
 100
 101 /* machine dependent includes */
 102 #ifdef HAVE_LINUX_VERSION_H
 103 #include <linux/version.h>
 104 #endif /* HAVE_LINUX_VERSION_H */
 105
 106 #ifdef HAVE_ASM_TYPES_H
 107 #include <asm/types.h>
 108 #endif /* HAVE_ASM_TYPES_H */
 109
 110 /* misc include group */
 111 #include <stdarg.h>
 112 #if !(defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)
 113 /* Not C99; do we need to define va_copy? */
 114 #ifndef va_copy
 115 #ifdef __va_copy
 116 #define va_copy(DST,SRC) __va_copy(DST,SRC)
 117 #else
 118 /* Now we are desperate; this should work on many typical platforms.
 119    But this is slightly dangerous, because the standard does not require
 120    va_copy to be a macro. */
 121 #define va_copy(DST,SRC) memcpy(&(DST), &(SRC), sizeof(va_list))
 122 #warning "Not C99 and no va_copy macro available, falling back to memcpy"
 123 #endif /* __va_copy */
 124 #endif /* !va_copy */
 125 #endif /* !C99 */
 126
 127
 128 #ifdef HAVE_LCAPS
 129 #include <sys/capability.h>
 130 #include <sys/prctl.h>
 131 #endif /* HAVE_LCAPS */
 132
 133 #ifdef HAVE_SOLARIS_CAPABILITIES
 134 #include <priv.h>
 135 #endif /* HAVE_SOLARIS_CAPABILITIES */
 136
 137 /* network include group */
 138
 139 #include <sys/socket.h>
 140
 141 #ifdef HAVE_SYS_SOCKIO_H
 142 #include <sys/sockio.h>
 143 #endif /* HAVE_SYS_SOCKIO_H */
 144
 145 #ifdef HAVE_NETINET_IN_H
 146 #include <netinet/in.h>
 147 #endif /* HAVE_NETINET_IN_H */
 148 #include <netinet/in_systm.h>
 149 #include <netinet/ip.h>
 150 #include <netinet/tcp.h>
 151
 152 #ifdef HAVE_NET_NETOPT_H
 153 #include <net/netopt.h>
 154 #endif /* HAVE_NET_NETOPT_H */
 155
 156 #include <net/if.h>
 157
 158 #ifdef HAVE_NET_IF_DL_H
 159 #include <net/if_dl.h>
 160 #endif /* HAVE_NET_IF_DL_H */
 161
 162 #ifdef HAVE_NET_IF_VAR_H
 163 #include <net/if_var.h>
 164 #endif /* HAVE_NET_IF_VAR_H */
 165
 166 #ifdef HAVE_NET_ROUTE_H
 167 #include <net/route.h>
 168 #endif /* HAVE_NET_ROUTE_H */
 169
 170 #ifdef HAVE_NETLINK
 171 #include <linux/netlink.h>
 172 #include <linux/rtnetlink.h>
 173 #include <linux/filter.h>
 174 #include <stddef.h>
 175 #else
 176 #define RT_TABLE_MAIN           0
 177 #endif /* HAVE_NETLINK */
 178
 179 #ifdef HAVE_NETDB_H
 180 #include <netdb.h>
 181 #endif /* HAVE_NETDB_H */
 182
 183 #include <arpa/inet.h>
 184
 185 #ifdef HAVE_INET_ND_H
 186 #include <inet/nd.h>
 187 #endif /* HAVE_INET_ND_H */
 188
 189 #ifdef HAVE_NETINET_IN_VAR_H
 190 #include <netinet/in_var.h>
 191 #endif /* HAVE_NETINET_IN_VAR_H */
 192
 193 #ifdef HAVE_NETINET6_IN6_VAR_H
 194 #include <netinet6/in6_var.h>
 195 #endif /* HAVE_NETINET6_IN6_VAR_H */
 196
 197 #ifdef HAVE_NETINET_IN6_VAR_H
 198 #include <netinet/in6_var.h>
 199 #endif /* HAVE_NETINET_IN6_VAR_H */
 200
 201 #ifdef HAVE_NETINET6_IN_H
 202 #include <netinet6/in.h>
 203 #endif /* HAVE_NETINET6_IN_H */
 204
 205
 206 #ifdef HAVE_NETINET6_IP6_H
 207 #include <netinet6/ip6.h>
 208 #endif /* HAVE_NETINET6_IP6_H */
 209
 210 #ifdef HAVE_NETINET_ICMP6_H
 211 #include <netinet/icmp6.h>
 212 #endif /* HAVE_NETINET_ICMP6_H */
 213
 214 #ifdef HAVE_NETINET6_ND6_H
 215 #include <netinet6/nd6.h>
 216 #endif /* HAVE_NETINET6_ND6_H */
 217
 218 /* Some systems do not define UINT32_MAX, etc.. from inttypes.h
 219  * e.g. this makes life easier for FBSD 4.11 users.
 220  */
 221 #ifndef INT8_MAX
 222 #define INT8_MAX        (127)
 223 #endif
 224 #ifndef INT16_MAX
 225 #define INT16_MAX       (32767)
 226 #endif
 227 #ifndef INT32_MAX
 228 #define INT32_MAX       (2147483647)
 229 #endif
 230 #ifndef UINT8_MAX
 231 #define UINT8_MAX       (255U)
 232 #endif
 233 #ifndef UINT16_MAX
 234 #define UINT16_MAX      (65535U)
 235 #endif
 236 #ifndef UINT32_MAX
 237 #define UINT32_MAX      (4294967295U)
 238 #endif
 239
 240 #ifdef HAVE_GLIBC_BACKTRACE
 241 #include <execinfo.h>
 242 #endif /* HAVE_GLIBC_BACKTRACE */
 243
 244 #ifdef BSDI_NRL
 245
 246 #ifdef HAVE_NETINET6_IN6_H
 247 #include <netinet6/in6.h>
 248 #endif /* HAVE_NETINET6_IN6_H */
 249
 250 #ifdef NRL
 251 #include <netinet6/in6.h>
 252 #endif /* NRL */
 253
 254 #define IN6_ARE_ADDR_EQUAL IN6_IS_ADDR_EQUAL
 255
 256 #endif /* BSDI_NRL */
 257
 258 /* Local includes: */
 259 #if !(defined(__GNUC__) || defined(VTYSH_EXTRACT_PL))
 260 #define __attribute__(x)
 261 #endif  /* !__GNUC__ || VTYSH_EXTRACT_PL */
 262
 263 #include "zassert.h"
 264 #include "str.h"
 265
 266
 267 #ifdef HAVE_BROKEN_CMSG_FIRSTHDR
 268 /* This bug is present in Solaris 8 and pre-patch Solaris 9 <sys/socket.h>;
 269    please refer to http://bugzilla.quagga.net/show_bug.cgi?id=142 */
 270
 271 /* Check that msg_controllen is large enough. */
 272 #define ZCMSG_FIRSTHDR(mhdr) \
 273   (((size_t)((mhdr)->msg_controllen) >= sizeof(struct cmsghdr)) ? \
 274    CMSG_FIRSTHDR(mhdr) : (struct cmsghdr *)NULL)
 275
 276 #warning "CMSG_FIRSTHDR is broken on this platform, using a workaround"
 277
 278 #else /* HAVE_BROKEN_CMSG_FIRSTHDR */
 279 #define ZCMSG_FIRSTHDR(M) CMSG_FIRSTHDR(M)
 280 #endif /* HAVE_BROKEN_CMSG_FIRSTHDR */
 281
 282
 283
 284 /*
 285  * RFC 3542 defines several macros for using struct cmsghdr.
 286  * Here, we define those that are not present
 287  */
 288
 289 /*
 290  * Internal defines, for use only in this file.
 291  * These are likely wrong on other than ILP32 machines, so warn.
 292  */
 293 #ifndef _CMSG_DATA_ALIGN
 294 #define _CMSG_DATA_ALIGN(n)           (((n) + 3) & ~3)
 295 #endif /* _CMSG_DATA_ALIGN */
 296
 297 #ifndef _CMSG_HDR_ALIGN
 298 #define _CMSG_HDR_ALIGN(n)            (((n) + 3) & ~3)
 299 #endif /* _CMSG_HDR_ALIGN */
 300
 301 /*
 302  * CMSG_SPACE and CMSG_LEN are required in RFC3542, but were new in that
 303  * version.
 304  */
 305 #ifndef CMSG_SPACE
 306 #define CMSG_SPACE(l)       (_CMSG_DATA_ALIGN(sizeof(struct cmsghdr)) + \
 307                               _CMSG_HDR_ALIGN(l))
 308 #warning "assuming 4-byte alignment for CMSG_SPACE"
 309 #endif  /* CMSG_SPACE */
 310
 311
 312 #ifndef CMSG_LEN
 313 #define CMSG_LEN(l)         (_CMSG_DATA_ALIGN(sizeof(struct cmsghdr)) + (l))
 314 #warning "assuming 4-byte alignment for CMSG_LEN"
 315 #endif /* CMSG_LEN */
 316
 317
 318 /*  The definition of struct in_pktinfo is missing in old version of
 319     GLIBC 2.1 (Redhat 6.1).  */
 320 #if defined (GNU_LINUX) && ! defined (HAVE_STRUCT_IN_PKTINFO)
 321 struct in_pktinfo
 322 {
 323   int ipi_ifindex;
 324   struct in_addr ipi_spec_dst;
 325   struct in_addr ipi_addr;
 326 };
 327 #endif
 328
 329 /*
 330  * OSPF Fragmentation / fragmented writes
 331  *
 332  * ospfd can support writing fragmented packets, for cases where
 333  * kernel will not fragment IP_HDRINCL and/or multicast destined
 334  * packets (ie TTBOMK all kernels, BSD, SunOS, Linux). However,
 335  * SunOS, probably BSD too, clobber the user supplied IP ID and IP
 336  * flags fields, hence user-space fragmentation will not work.
 337  * Only Linux is known to leave IP header unmolested.
 338  * Further, fragmentation really should be done the kernel, which already
 339  * supports it, and which avoids nasty IP ID state problems.
 340  *
 341  * Fragmentation of OSPF packets can be required on networks with router
 342  * with many many interfaces active in one area, or on networks with links
 343  * with low MTUs.
 344  */
 345 #ifdef GNU_LINUX
 346 #define WANT_OSPF_WRITE_FRAGMENT
 347 #endif
 348
 349 /*
 350  * IP_HDRINCL / struct ip byte order
 351  *
 352  * Linux: network byte order
 353  * *BSD: network, except for length and offset. (cf Stevens)
 354  * SunOS: nominally as per BSD. but bug: network order on LE.
 355  * OpenBSD: network byte order, apart from older versions which are as per
 356  *          *BSD
 357  */
 358 #if defined(__NetBSD__) || defined(__FreeBSD__) \
 359    || (defined(__OpenBSD__) && (OpenBSD < 200311)) \
 360    || (defined(SUNOS_5) && defined(WORDS_BIGENDIAN))
 361 #define HAVE_IP_HDRINCL_BSD_ORDER
 362 #endif
 363
 364 /* Define BYTE_ORDER, if not defined. Useful for compiler conditional
 365  * code, rather than preprocessor conditional.
 366  * Not all the world has this BSD define.
 367  */
 368 #ifndef BYTE_ORDER
 369 #define BIG_ENDIAN      4321    /* least-significant byte first (vax, pc) */
 370 #define LITTLE_ENDIAN   1234    /* most-significant byte first (IBM, net) */
 371 #define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp) */
 372
 373 #if defined(WORDS_BIGENDIAN)
 374 #define BYTE_ORDER      BIG_ENDIAN
 375 #else /* !WORDS_BIGENDIAN */
 376 #define BYTE_ORDER      LITTLE_ENDIAN
 377 #endif /* WORDS_BIGENDIAN */
 378
 379 #endif /* ndef BYTE_ORDER */
 380
 381 /* MAX / MIN are not commonly defined, but useful */
 382 #ifndef MAX
 383 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 384 #endif
 385 #ifndef MIN
 386 #define MIN(a, b) ((a) < (b) ? (a) : (b))
 387 #endif
 388
 389 /* For old definition. */
 390 #ifndef IN6_ARE_ADDR_EQUAL
 391 #define IN6_ARE_ADDR_EQUAL IN6_IS_ADDR_EQUAL
 392 #endif /* IN6_ARE_ADDR_EQUAL */
 393
 394 /* default zebra TCP port for zclient */
 395 #define ZEBRA_PORT                      2600
 396
 397 /* Zebra message types. */
 398 #define ZEBRA_INTERFACE_ADD                1
 399 #define ZEBRA_INTERFACE_DELETE             2
 400 #define ZEBRA_INTERFACE_ADDRESS_ADD        3
 401 #define ZEBRA_INTERFACE_ADDRESS_DELETE     4
 402 #define ZEBRA_INTERFACE_UP                 5
 403 #define ZEBRA_INTERFACE_DOWN               6
 404 #define ZEBRA_IPV4_ROUTE_ADD               7
 405 #define ZEBRA_IPV4_ROUTE_DELETE            8
 406 #define ZEBRA_IPV6_ROUTE_ADD               9
 407 #define ZEBRA_IPV6_ROUTE_DELETE           10
 408 #define ZEBRA_REDISTRIBUTE_ADD            11
 409 #define ZEBRA_REDISTRIBUTE_DELETE         12
 410 #define ZEBRA_REDISTRIBUTE_DEFAULT_ADD    13
 411 #define ZEBRA_REDISTRIBUTE_DEFAULT_DELETE 14
 412 #define ZEBRA_IPV4_NEXTHOP_LOOKUP         15
 413 #define ZEBRA_IPV6_NEXTHOP_LOOKUP         16
 414 #define ZEBRA_IPV4_IMPORT_LOOKUP          17
 415 #define ZEBRA_IPV6_IMPORT_LOOKUP          18
 416 #define ZEBRA_INTERFACE_RENAME            19
 417 #define ZEBRA_ROUTER_ID_ADD               20
 418 #define ZEBRA_ROUTER_ID_DELETE            21
 419 #define ZEBRA_ROUTER_ID_UPDATE            22
 420 #define ZEBRA_MESSAGE_MAX                 23
 421
 422 /* Marker value used in new Zserv, in the byte location corresponding
 423  * the command value in the old zserv header. To allow old and new
 424  * Zserv headers to be distinguished from each other.
 425  */
 426 #define ZEBRA_HEADER_MARKER              255
 427
 428 /* Zebra route's types. */
 429 #define ZEBRA_ROUTE_SYSTEM               0
 430 #define ZEBRA_ROUTE_KERNEL               1
 431 #define ZEBRA_ROUTE_CONNECT              2
 432 #define ZEBRA_ROUTE_STATIC               3
 433 #define ZEBRA_ROUTE_RIP                  4
 434 #define ZEBRA_ROUTE_RIPNG                5
 435 #define ZEBRA_ROUTE_OSPF                 6
 436 #define ZEBRA_ROUTE_OSPF6                7
 437 #define ZEBRA_ROUTE_ISIS                 8
 438 #define ZEBRA_ROUTE_BGP                  9
 439 #define ZEBRA_ROUTE_HSLS                 10
 440 #define ZEBRA_ROUTE_MAX                  11
 441
 442 /* Note: whenever a new route-type or zserv-command is added the
 443  * corresponding {command,route}_types[] table in lib/log.c MUST be
 444  * updated! */
 445
 446 /* Map a route type to a string.  For example, ZEBRA_ROUTE_RIPNG -> "ripng". */
 447 extern const char *zebra_route_string(unsigned int route_type);
 448 /* Map a route type to a char.  For example, ZEBRA_ROUTE_RIPNG -> 'R'. */
 449 extern char zebra_route_char(unsigned int route_type);
 450 /* Map a zserv command type to the same string,
 451  * e.g. ZEBRA_INTERFACE_ADD -> "ZEBRA_INTERFACE_ADD" */
 452 /* Map a protocol name to its number. e.g. ZEBRA_ROUTE_BGP->9*/
 453 extern int proto_name2num(const char *s);
 454
 455 extern const char *zserv_command_string (unsigned int command);
 456
 457 /* Zebra's family types. */
 458 #define ZEBRA_FAMILY_IPV4                1
 459 #define ZEBRA_FAMILY_IPV6                2
 460 #define ZEBRA_FAMILY_MAX                 3
 461
 462 /* Error codes of zebra. */
 463 #define ZEBRA_ERR_NOERROR                0
 464 #define ZEBRA_ERR_RTEXIST               -1
 465 #define ZEBRA_ERR_RTUNREACH             -2
 466 #define ZEBRA_ERR_EPERM                 -3
 467 #define ZEBRA_ERR_RTNOEXIST             -4
 468 #define ZEBRA_ERR_KERNEL                -5
 469
 470 /* Zebra message flags */
 471 #define ZEBRA_FLAG_INTERNAL           0x01
 472 #define ZEBRA_FLAG_SELFROUTE          0x02
 473 #define ZEBRA_FLAG_BLACKHOLE          0x04
 474 #define ZEBRA_FLAG_IBGP               0x08
 475 #define ZEBRA_FLAG_SELECTED           0x10
 476 #define ZEBRA_FLAG_CHANGED            0x20
 477 #define ZEBRA_FLAG_STATIC             0x40
 478 #define ZEBRA_FLAG_REJECT             0x80
 479
 480 /* Zebra nexthop flags. */
 481 #define ZEBRA_NEXTHOP_IFINDEX            1
 482 #define ZEBRA_NEXTHOP_IFNAME             2
 483 #define ZEBRA_NEXTHOP_IPV4               3
 484 #define ZEBRA_NEXTHOP_IPV4_IFINDEX       4
 485 #define ZEBRA_NEXTHOP_IPV4_IFNAME        5
 486 #define ZEBRA_NEXTHOP_IPV6               6
 487 #define ZEBRA_NEXTHOP_IPV6_IFINDEX       7
 488 #define ZEBRA_NEXTHOP_IPV6_IFNAME        8
 489 #define ZEBRA_NEXTHOP_BLACKHOLE          9
 490
 491 #ifndef INADDR_LOOPBACK
 492 #define INADDR_LOOPBACK 0x7f000001      /* Internet address 127.0.0.1.  */
 493 #endif
 494
 495 /* Address family numbers from RFC1700. */
 496 #define AFI_IP                    1
 497 #define AFI_IP6                   2
 498 #define AFI_MAX                   3
 499
 500 /* Subsequent Address Family Identifier. */
 501 #define SAFI_UNICAST              1
 502 #define SAFI_MULTICAST            2
 503 #define SAFI_RESERVED_3           3
 504 #define SAFI_MPLS_VPN             4
 505 #define SAFI_MAX                  5
 506
 507 /* Filter direction.  */
 508 #define FILTER_IN                 0
 509 #define FILTER_OUT                1
 510 #define FILTER_MAX                2
 511
 512 /* Default Administrative Distance of each protocol. */
 513 #define ZEBRA_KERNEL_DISTANCE_DEFAULT      0
 514 #define ZEBRA_CONNECT_DISTANCE_DEFAULT     0
 515 #define ZEBRA_STATIC_DISTANCE_DEFAULT      1
 516 #define ZEBRA_RIP_DISTANCE_DEFAULT       120
 517 #define ZEBRA_RIPNG_DISTANCE_DEFAULT     120
 518 #define ZEBRA_OSPF_DISTANCE_DEFAULT      110
 519 #define ZEBRA_OSPF6_DISTANCE_DEFAULT     110
 520 #define ZEBRA_ISIS_DISTANCE_DEFAULT      115
 521 #define ZEBRA_IBGP_DISTANCE_DEFAULT      200
 522 #define ZEBRA_EBGP_DISTANCE_DEFAULT       20
 523
 524 /* Flag manipulation macros. */
 525 #define CHECK_FLAG(V,F)      ((V) & (F))
 526 #define SET_FLAG(V,F)        (V) |= (F)
 527 #define UNSET_FLAG(V,F)      (V) &= ~(F)
 528
 529 /* AFI and SAFI type. */
 530 typedef u_int16_t afi_t;
 531 typedef u_int8_t safi_t;
 532
 533 /* Zebra types. Used in Zserv message header. */
 534 typedef u_int16_t zebra_size_t;
 535 typedef u_int16_t zebra_command_t;
 536
 537 /* FIFO -- first in first out structure and macros.  */
 538 struct fifo
 539 {
 540   struct fifo *next;
 541   struct fifo *prev;
 542 };
 543
 544 #define FIFO_INIT(F)                                  \
 545   do {                                                \
 546     struct fifo *Xfifo = (struct fifo *)(F);          \
 547     Xfifo->next = Xfifo->prev = Xfifo;                \
 548   } while (0)
 549
 550 #define FIFO_ADD(F,N)                                 \
 551   do {                                                \
 552     struct fifo *Xfifo = (struct fifo *)(F);          \
 553     struct fifo *Xnode = (struct fifo *)(N);          \
 554     Xnode->next = Xfifo;                              \
 555     Xnode->prev = Xfifo->prev;                        \
 556     Xfifo->prev = Xfifo->prev->next = Xnode;          \
 557   } while (0)
 558
 559 #define FIFO_DEL(N)                                   \
 560   do {                                                \
 561     struct fifo *Xnode = (struct fifo *)(N);          \
 562     Xnode->prev->next = Xnode->next;                  \
 563     Xnode->next->prev = Xnode->prev;                  \
 564   } while (0)
 565
 566 #define FIFO_HEAD(F)                                  \
 567   ((((struct fifo *)(F))->next == (struct fifo *)(F)) \
 568   ? NULL : (F)->next)
 569
 570 #define FIFO_EMPTY(F)                                 \
 571   (((struct fifo *)(F))->next == (struct fifo *)(F))
 572
 573 #define FIFO_TOP(F)                                   \
 574   (FIFO_EMPTY(F) ? NULL : ((struct fifo *)(F))->next)
 575
 576 #endif /* _ZEBRA_H */