lib/sockopt.c

   1 /* setsockopt functions
   2  * Copyright (C) 1999 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
  22 #include <zebra.h>
  23 #include "log.h"
  24 #include "sockopt.h"
  25 #include "sockunion.h"
  26
  27 int
  28 setsockopt_so_recvbuf (int sock, int size)
  29 {
  30   int ret;
  31
  32   if ( (ret = setsockopt (sock, SOL_SOCKET, SO_RCVBUF, (char *)
  33                           &size, sizeof (int))) < 0)
  34     zlog_err ("fd %d: can't setsockopt SO_RCVBUF to %d: %s",
  35               sock,size,safe_strerror(errno));
  36
  37   return ret;
  38 }
  39
  40 int
  41 setsockopt_so_sendbuf (const int sock, int size)
  42 {
  43   int ret = setsockopt (sock, SOL_SOCKET, SO_SNDBUF,
  44     (char *)&size, sizeof (int));
  45
  46   if (ret < 0)
  47     zlog_err ("fd %d: can't setsockopt SO_SNDBUF to %d: %s",
  48       sock, size, safe_strerror (errno));
  49
  50   return ret;
  51 }
  52
  53 int
  54 getsockopt_so_sendbuf (const int sock)
  55 {
  56   u_int32_t optval;
  57   socklen_t optlen = sizeof (optval);
  58   int ret = getsockopt (sock, SOL_SOCKET, SO_SNDBUF,
  59     (char *)&optval, &optlen);
  60   if (ret < 0)
  61   {
  62     zlog_err ("fd %d: can't getsockopt SO_SNDBUF: %d (%s)",
  63       sock, errno, safe_strerror (errno));
  64     return ret;
  65   }
  66   return optval;
  67 }
  68
  69 static void *
  70 getsockopt_cmsg_data (struct msghdr *msgh, int level, int type)
  71 {
  72   struct cmsghdr *cmsg;
  73   void *ptr = NULL;
  74
  75   for (cmsg = ZCMSG_FIRSTHDR(msgh);
  76        cmsg != NULL;
  77        cmsg = CMSG_NXTHDR(msgh, cmsg))
  78     if (cmsg->cmsg_level == level && cmsg->cmsg_type)
  79       return (ptr = CMSG_DATA(cmsg));
  80
  81   return NULL;
  82 }
  83
  84 #ifdef HAVE_IPV6
  85 /* Set IPv6 packet info to the socket. */
  86 int
  87 setsockopt_ipv6_pktinfo (int sock, int val)
  88 {
  89   int ret;
  90
  91 #ifdef IPV6_RECVPKTINFO         /*2292bis-01*/
  92   ret = setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
  93   if (ret < 0)
  94     zlog_warn ("can't setsockopt IPV6_RECVPKTINFO : %s", safe_strerror (errno));
  95 #else   /*RFC2292*/
  96   ret = setsockopt(sock, IPPROTO_IPV6, IPV6_PKTINFO, &val, sizeof(val));
  97   if (ret < 0)
  98     zlog_warn ("can't setsockopt IPV6_PKTINFO : %s", safe_strerror (errno));
  99 #endif /* INIA_IPV6 */
 100   return ret;
 101 }
 102
 103 /* Set multicast hops val to the socket. */
 104 int
 105 setsockopt_ipv6_checksum (int sock, int val)
 106 {
 107   int ret;
 108
 109 #ifdef GNU_LINUX
 110   ret = setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
 111 #else
 112   ret = setsockopt(sock, IPPROTO_IPV6, IPV6_CHECKSUM, &val, sizeof(val));
 113 #endif /* GNU_LINUX */
 114   if (ret < 0)
 115     zlog_warn ("can't setsockopt IPV6_CHECKSUM");
 116   return ret;
 117 }
 118
 119 /* Set multicast hops val to the socket. */
 120 int
 121 setsockopt_ipv6_multicast_hops (int sock, int val)
 122 {
 123   int ret;
 124
 125   ret = setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
 126   if (ret < 0)
 127     zlog_warn ("can't setsockopt IPV6_MULTICAST_HOPS");
 128   return ret;
 129 }
 130
 131 /* Set multicast hops val to the socket. */
 132 int
 133 setsockopt_ipv6_unicast_hops (int sock, int val)
 134 {
 135   int ret;
 136
 137   ret = setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
 138   if (ret < 0)
 139     zlog_warn ("can't setsockopt IPV6_UNICAST_HOPS");
 140   return ret;
 141 }
 142
 143 int
 144 setsockopt_ipv6_hoplimit (int sock, int val)
 145 {
 146   int ret;
 147
 148 #ifdef IPV6_RECVHOPLIMIT        /*2292bis-01*/
 149   ret = setsockopt (sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val));
 150   if (ret < 0)
 151     zlog_warn ("can't setsockopt IPV6_RECVHOPLIMIT");
 152 #else   /*RFC2292*/
 153   ret = setsockopt (sock, IPPROTO_IPV6, IPV6_HOPLIMIT, &val, sizeof(val));
 154   if (ret < 0)
 155     zlog_warn ("can't setsockopt IPV6_HOPLIMIT");
 156 #endif
 157   return ret;
 158 }
 159
 160 /* Set multicast loop zero to the socket. */
 161 int
 162 setsockopt_ipv6_multicast_loop (int sock, int val)
 163 {
 164   int ret;
 165
 166   ret = setsockopt (sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val,
 167                     sizeof (val));
 168   if (ret < 0)
 169     zlog_warn ("can't setsockopt IPV6_MULTICAST_LOOP");
 170   return ret;
 171 }
 172
 173 static int
 174 getsockopt_ipv6_ifindex (struct msghdr *msgh)
 175 {
 176   struct in6_pktinfo *pktinfo;
 177
 178   pktinfo = getsockopt_cmsg_data (msgh, IPPROTO_IPV6, IPV6_PKTINFO);
 179
 180   return pktinfo->ipi6_ifindex;
 181 }
 182
 183 int
 184 setsockopt_ipv6_tclass(int sock, int tclass)
 185 {
 186   int ret;
 187
 188   ret = setsockopt (sock, IPPROTO_IPV6, IPV6_TCLASS, &tclass, sizeof (tclass));
 189   if (ret < 0)
 190     zlog_warn ("Can't set IPV6_TCLASS option for fd %d to %#x: %s",
 191                sock, tclass, safe_strerror(errno));
 192   return ret;
 193 }
 194 #endif /* HAVE_IPV6 */
 195
 196 /*
 197  * Process multicast socket options for IPv4 in an OS-dependent manner.
 198  * Supported options are IP_{ADD,DROP}_MEMBERSHIP.
 199  *
 200  * Many operating systems have a limit on the number of groups that
 201  * can be joined per socket (where each group and local address
 202  * counts).  This impacts OSPF, which joins groups on each interface
 203  * using a single socket.  The limit is typically 20, derived from the
 204  * original BSD multicast implementation.  Some systems have
 205  * mechanisms for increasing this limit.
 206  *
 207  * In many 4.4BSD-derived systems, multicast group operations are not
 208  * allowed on interfaces that are not UP.  Thus, a previous attempt to
 209  * leave the group may have failed, leaving it still joined, and we
 210  * drop/join quietly to recover.  This may not be necessary, but aims to
 211  * defend against unknown behavior in that we will still return an error
 212  * if the second join fails.  It is not clear how other systems
 213  * (e.g. Linux, Solaris) behave when leaving groups on down interfaces,
 214  * but this behavior should not be harmful if they behave the same way,
 215  * allow leaves, or implicitly leave all groups joined to down interfaces.
 216  */
 217 int
 218 setsockopt_ipv4_multicast(int sock,
 219                         int optname,
 220                         unsigned int mcast_addr,
 221                         unsigned int ifindex)
 222 {
 223 #ifdef HAVE_RFC3678
 224   struct group_req gr;
 225   struct sockaddr_in *si;
 226   int ret;
 227   memset (&gr, 0, sizeof(gr));
 228   si = (struct sockaddr_in *)&gr.gr_group;
 229   gr.gr_interface = ifindex;
 230   si->sin_family = AF_INET;
 231 #ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
 232   si->sin_len = sizeof(struct sockaddr_in);
 233 #endif /* HAVE_STRUCT_SOCKADDR_IN_SIN_LEN */
 234   si->sin_addr.s_addr = mcast_addr;
 235   ret = setsockopt(sock, IPPROTO_IP, (optname == IP_ADD_MEMBERSHIP) ?
 236     MCAST_JOIN_GROUP : MCAST_LEAVE_GROUP, (void *)&gr, sizeof(gr));
 237   if ((ret < 0) && (optname == IP_ADD_MEMBERSHIP) && (errno == EADDRINUSE))
 238     {
 239       setsockopt(sock, IPPROTO_IP, MCAST_LEAVE_GROUP, (void *)&gr, sizeof(gr));
 240       ret = setsockopt(sock, IPPROTO_IP, MCAST_JOIN_GROUP, (void *)&gr, sizeof(gr));
 241     }
 242   return ret;
 243
 244 #elif defined(HAVE_STRUCT_IP_MREQN_IMR_IFINDEX) && !defined(__FreeBSD__)
 245   struct ip_mreqn mreqn;
 246   int ret;
 247
 248   assert(optname == IP_ADD_MEMBERSHIP || optname == IP_DROP_MEMBERSHIP);
 249   memset (&mreqn, 0, sizeof(mreqn));
 250
 251   mreqn.imr_multiaddr.s_addr = mcast_addr;
 252   mreqn.imr_ifindex = ifindex;
 253
 254   ret = setsockopt(sock, IPPROTO_IP, optname,
 255                    (void *)&mreqn, sizeof(mreqn));
 256   if ((ret < 0) && (optname == IP_ADD_MEMBERSHIP) && (errno == EADDRINUSE))
 257     {
 258       /* see above: handle possible problem when interface comes back up */
 259       char buf[1][INET_ADDRSTRLEN];
 260       zlog_info("setsockopt_ipv4_multicast attempting to drop and "
 261                 "re-add (fd %d, mcast %s, ifindex %u)",
 262                 sock,
 263                 inet_ntop(AF_INET, &mreqn.imr_multiaddr,
 264                           buf[0], sizeof(buf[0])), ifindex);
 265       setsockopt(sock, IPPROTO_IP, IP_DROP_MEMBERSHIP,
 266                  (void *)&mreqn, sizeof(mreqn));
 267       ret = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
 268                        (void *)&mreqn, sizeof(mreqn));
 269     }
 270   return ret;
 271
 272   /* Example defines for another OS, boilerplate off other code in this
 273      function, AND handle optname as per other sections for consistency !! */
 274   /* #elif  defined(BOGON_NIX) && EXAMPLE_VERSION_CODE > -100000 */
 275   /* Add your favourite OS here! */
 276
 277 #elif defined(HAVE_BSD_STRUCT_IP_MREQ_HACK) /* #if OS_TYPE */
 278   /* standard BSD API */
 279
 280   struct in_addr m;
 281   struct ip_mreq mreq;
 282   int ret;
 283
 284   assert(optname == IP_ADD_MEMBERSHIP || optname == IP_DROP_MEMBERSHIP);
 285
 286   m.s_addr = htonl(ifindex);
 287
 288   memset (&mreq, 0, sizeof(mreq));
 289   mreq.imr_multiaddr.s_addr = mcast_addr;
 290   mreq.imr_interface = m;
 291
 292   ret = setsockopt (sock, IPPROTO_IP, optname, (void *)&mreq, sizeof(mreq));
 293   if ((ret < 0) && (optname == IP_ADD_MEMBERSHIP) && (errno == EADDRINUSE))
 294     {
 295       /* see above: handle possible problem when interface comes back up */
 296       char buf[1][INET_ADDRSTRLEN];
 297       zlog_info("setsockopt_ipv4_multicast attempting to drop and "
 298                 "re-add (fd %d, mcast %s, ifindex %u)",
 299                 sock,
 300                 inet_ntop(AF_INET, &mreq.imr_multiaddr,
 301                           buf[0], sizeof(buf[0])), ifindex);
 302       setsockopt (sock, IPPROTO_IP, IP_DROP_MEMBERSHIP,
 303                   (void *)&mreq, sizeof(mreq));
 304       ret = setsockopt (sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
 305                         (void *)&mreq, sizeof(mreq));
 306     }
 307   return ret;
 308
 309 #else
 310   #error "Unsupported multicast API"
 311 #endif /* #if OS_TYPE */
 312
 313 }
 314
 315 /*
 316  * Set IP_MULTICAST_IF socket option in an OS-dependent manner.
 317  */
 318 int
 319 setsockopt_ipv4_multicast_if(int sock,
 320                         unsigned int ifindex)
 321 {
 322
 323 #ifdef HAVE_STRUCT_IP_MREQN_IMR_IFINDEX
 324   struct ip_mreqn mreqn;
 325   memset (&mreqn, 0, sizeof(mreqn));
 326
 327   mreqn.imr_ifindex = ifindex;
 328   return setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF, (void *)&mreqn, sizeof(mreqn));
 329
 330   /* Example defines for another OS, boilerplate off other code in this
 331      function */
 332   /* #elif  defined(BOGON_NIX) && EXAMPLE_VERSION_CODE > -100000 */
 333   /* Add your favourite OS here! */
 334 #elif defined(HAVE_BSD_STRUCT_IP_MREQ_HACK)
 335   struct in_addr m;
 336
 337   m.s_addr = htonl(ifindex);
 338
 339   return setsockopt (sock, IPPROTO_IP, IP_MULTICAST_IF, (void *)&m, sizeof(m));
 340 #else
 341   #error "Unsupported multicast API"
 342 #endif
 343 }
 344
 345 static int
 346 setsockopt_ipv4_ifindex (int sock, int val)
 347 {
 348   int ret;
 349
 350 #if defined (IP_PKTINFO)
 351   if ((ret = setsockopt (sock, IPPROTO_IP, IP_PKTINFO, &val, sizeof (val))) < 0)
 352     zlog_warn ("Can't set IP_PKTINFO option for fd %d to %d: %s",
 353                sock,val,safe_strerror(errno));
 354 #elif defined (IP_RECVIF)
 355   if ((ret = setsockopt (sock, IPPROTO_IP, IP_RECVIF, &val, sizeof (val))) < 0)
 356     zlog_warn ("Can't set IP_RECVIF option for fd %d to %d: %s",
 357                sock,val,safe_strerror(errno));
 358 #else
 359 #warning "Neither IP_PKTINFO nor IP_RECVIF is available."
 360 #warning "Will not be able to receive link info."
 361 #warning "Things might be seriously broken.."
 362   /* XXX Does this ever happen?  Should there be a zlog_warn message here? */
 363   ret = -1;
 364 #endif
 365   return ret;
 366 }
 367
 368 int
 369 setsockopt_ipv4_tos(int sock, int tos)
 370 {
 371   int ret;
 372
 373   ret = setsockopt (sock, IPPROTO_IP, IP_TOS, &tos, sizeof (tos));
 374   if (ret < 0)
 375     zlog_warn ("Can't set IP_TOS option for fd %d to %#x: %s",
 376                sock, tos, safe_strerror(errno));
 377   return ret;
 378 }
 379
 380
 381 int
 382 setsockopt_ifindex (int af, int sock, int val)
 383 {
 384   int ret = -1;
 385
 386   switch (af)
 387     {
 388       case AF_INET:
 389         ret = setsockopt_ipv4_ifindex (sock, val);
 390         break;
 391 #ifdef HAVE_IPV6
 392       case AF_INET6:
 393         ret = setsockopt_ipv6_pktinfo (sock, val);
 394         break;
 395 #endif
 396       default:
 397         zlog_warn ("setsockopt_ifindex: unknown address family %d", af);
 398     }
 399   return ret;
 400 }
 401
 402 /*
 403  * Requires: msgh is not NULL and points to a valid struct msghdr, which
 404  * may or may not have control data about the incoming interface.
 405  *
 406  * Returns the interface index (small integer >= 1) if it can be
 407  * determined, or else 0.
 408  */
 409 static int
 410 getsockopt_ipv4_ifindex (struct msghdr *msgh)
 411 {
 412   /* XXX: initialize to zero?  (Always overwritten, so just cosmetic.) */
 413   int ifindex = -1;
 414
 415 #if defined(IP_PKTINFO)
 416 /* Linux pktinfo based ifindex retrieval */
 417   struct in_pktinfo *pktinfo;
 418
 419   pktinfo =
 420     (struct in_pktinfo *)getsockopt_cmsg_data (msgh, IPPROTO_IP, IP_PKTINFO);
 421   /* XXX Can pktinfo be NULL?  Clean up post 0.98. */
 422   ifindex = pktinfo->ipi_ifindex;
 423
 424 #elif defined(IP_RECVIF)
 425
 426   /* retrieval based on IP_RECVIF */
 427
 428 #ifndef SUNOS_5
 429   /* BSD systems use a sockaddr_dl as the control message payload. */
 430   struct sockaddr_dl *sdl;
 431 #else
 432   /* SUNOS_5 uses an integer with the index. */
 433   int *ifindex_p;
 434 #endif /* SUNOS_5 */
 435
 436 #ifndef SUNOS_5
 437   /* BSD */
 438   sdl =
 439     (struct sockaddr_dl *)getsockopt_cmsg_data (msgh, IPPROTO_IP, IP_RECVIF);
 440   if (sdl != NULL)
 441     ifindex = sdl->sdl_index;
 442   else
 443     ifindex = 0;
 444 #else
 445   /*
 446    * Solaris.  On Solaris 8, IP_RECVIF is defined, but the call to
 447    * enable it fails with errno=99, and the struct msghdr has
 448    * controllen 0.
 449    */
 450   ifindex_p = (uint_t *)getsockopt_cmsg_data (msgh, IPPROTO_IP, IP_RECVIF);
 451   if (ifindex_p != NULL)
 452     ifindex = *ifindex_p;
 453   else
 454     ifindex = 0;
 455 #endif /* SUNOS_5 */
 456
 457 #else
 458   /*
 459    * Neither IP_PKTINFO nor IP_RECVIF defined - warn at compile time.
 460    * XXX Decide if this is a core service, or if daemons have to cope.
 461    * Since Solaris 8 and OpenBSD seem not to provide it, it seems that
 462    * daemons have to cope.
 463    */
 464 #warning "getsockopt_ipv4_ifindex: Neither IP_PKTINFO nor IP_RECVIF defined."
 465 #warning "Some daemons may fail to operate correctly!"
 466   ifindex = 0;
 467
 468 #endif /* IP_PKTINFO */
 469
 470   return ifindex;
 471 }
 472
 473 /* return ifindex, 0 if none found */
 474 int
 475 getsockopt_ifindex (int af, struct msghdr *msgh)
 476 {
 477   switch (af)
 478     {
 479       case AF_INET:
 480         return (getsockopt_ipv4_ifindex (msgh));
 481         break;
 482 #ifdef HAVE_IPV6
 483       case AF_INET6:
 484         return (getsockopt_ipv6_ifindex (msgh));
 485         break;
 486 #endif
 487       default:
 488         zlog_warn ("getsockopt_ifindex: unknown address family %d", af);
 489         return 0;
 490     }
 491 }
 492
 493 /* swab iph between order system uses for IP_HDRINCL and host order */
 494 void
 495 sockopt_iphdrincl_swab_htosys (struct ip *iph)
 496 {
 497   /* BSD and derived take iph in network order, except for
 498    * ip_len and ip_off
 499    */
 500 #ifndef HAVE_IP_HDRINCL_BSD_ORDER
 501   iph->ip_len = htons(iph->ip_len);
 502   iph->ip_off = htons(iph->ip_off);
 503 #endif /* HAVE_IP_HDRINCL_BSD_ORDER */
 504
 505   iph->ip_id = htons(iph->ip_id);
 506 }
 507
 508 void
 509 sockopt_iphdrincl_swab_systoh (struct ip *iph)
 510 {
 511 #ifndef HAVE_IP_HDRINCL_BSD_ORDER
 512   iph->ip_len = ntohs(iph->ip_len);
 513   iph->ip_off = ntohs(iph->ip_off);
 514 #endif /* HAVE_IP_HDRINCL_BSD_ORDER */
 515
 516   iph->ip_id = ntohs(iph->ip_id);
 517 }
 518
 519 int
 520 sockopt_tcp_signature (int sock, union sockunion *su, const char *password)
 521 {
 522 #if defined(HAVE_TCP_MD5_LINUX24) && defined(GNU_LINUX)
 523   /* Support for the old Linux 2.4 TCP-MD5 patch, taken from Hasso Tepper's
 524    * version of the Quagga patch (based on work by Rick Payne, and Bruce
 525    * Simpson)
 526    */
 527 #define TCP_MD5_AUTH 13
 528 #define TCP_MD5_AUTH_ADD 1
 529 #define TCP_MD5_AUTH_DEL 2
 530   struct tcp_rfc2385_cmd {
 531     u_int8_t     command;    /* Command - Add/Delete */
 532     u_int32_t    address;    /* IPV4 address associated */
 533     u_int8_t     keylen;     /* MD5 Key len (do NOT assume 0 terminated ascii) */
 534     void         *key;       /* MD5 Key */
 535   } cmd;
 536   struct in_addr *addr = &su->sin.sin_addr;
 537
 538   cmd.command = (password != NULL ? TCP_MD5_AUTH_ADD : TCP_MD5_AUTH_DEL);
 539   cmd.address = addr->s_addr;
 540   cmd.keylen = (password != NULL ? strlen (password) : 0);
 541   cmd.key = password;
 542
 543   return setsockopt (sock, IPPROTO_TCP, TCP_MD5_AUTH, &cmd, sizeof cmd);
 544
 545 #elif HAVE_DECL_TCP_MD5SIG
 546   int ret;
 547 #ifndef GNU_LINUX
 548   /*
 549    * XXX Need to do PF_KEY operation here to add/remove an SA entry,
 550    * and add/remove an SP entry for this peer's packet flows also.
 551    */
 552   int md5sig = password && *password ? 1 : 0;
 553 #else
 554   int keylen = password ? strlen (password) : 0;
 555   struct tcp_md5sig md5sig;
 556   union sockunion *su2, *susock;
 557
 558   /* Figure out whether the socket and the sockunion are the same family..
 559    * adding AF_INET to AF_INET6 needs to be v4 mapped, you'd think..
 560    */
 561   if (!(susock = sockunion_getsockname (sock)))
 562     return -1;
 563
 564   if (susock->sa.sa_family == su->sa.sa_family)
 565     su2 = su;
 566   else
 567     {
 568       /* oops.. */
 569       su2 = susock;
 570
 571       if (su2->sa.sa_family == AF_INET)
 572         {
 573           sockunion_free (susock);
 574           return 0;
 575         }
 576
 577 #ifdef HAVE_IPV6
 578       /* If this does not work, then all users of this sockopt will need to
 579        * differentiate between IPv4 and IPv6, and keep seperate sockets for
 580        * each.
 581        *
 582        * Sadly, it doesn't seem to work at present. It's unknown whether
 583        * this is a bug or not.
 584        */
 585       if (su2->sa.sa_family == AF_INET6
 586           && su->sa.sa_family == AF_INET)
 587         {
 588            su2->sin6.sin6_family = AF_INET6;
 589            /* V4Map the address */
 590            memset (&su2->sin6.sin6_addr, 0, sizeof (struct in6_addr));
 591            su2->sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
 592            memcpy (&su2->sin6.sin6_addr.s6_addr32[3], &su->sin.sin_addr, 4);
 593         }
 594 #endif
 595     }
 596
 597   memset (&md5sig, 0, sizeof (md5sig));
 598   memcpy (&md5sig.tcpm_addr, su2, sizeof (*su2));
 599   md5sig.tcpm_keylen = keylen;
 600   if (keylen)
 601     memcpy (md5sig.tcpm_key, password, keylen);
 602   sockunion_free (susock);
 603 #endif /* GNU_LINUX */
 604   if ((ret = setsockopt (sock, IPPROTO_TCP, TCP_MD5SIG, &md5sig, sizeof md5sig)) < 0)
 605     {
 606       /* ENOENT is harmless.  It is returned when we clear a password for which
 607          one was not previously set. */
 608       if (ENOENT == errno)
 609         ret = 0;
 610       else
 611         zlog_err ("sockopt_tcp_signature: setsockopt(%d): %s",
 612                   sock, safe_strerror(errno));
 613     }
 614   return ret;
 615 #else /* HAVE_TCP_MD5SIG */
 616   return -2;
 617 #endif /* !HAVE_TCP_MD5SIG */
 618 }