eigrpd/eigrp_hello.c

   1 /*
   2  * EIGRP Sending and Receiving EIGRP Hello Packets.
   3  * Copyright (C) 2013-2016
   4  * Authors:
   5  *   Donnie Savage
   6  *   Jan Janovic
   7  *   Matej Perina
   8  *   Peter Orsag
   9  *   Peter Paluch
  10  *   Frantisek Gazo
  11  *   Tomas Hvorkovy
  12  *   Martin Kontsek
  13  *   Lukas Koribsky
  14  *
  15  * This file is part of GNU Zebra.
  16  *
  17  * GNU Zebra is free software; you can redistribute it and/or modify it
  18  * under the terms of the GNU General Public License as published by the
  19  * Free Software Foundation; either version 2, or (at your option) any
  20  * later version.
  21  *
  22  * GNU Zebra is distributed in the hope that it will be useful, but
  23  * WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25  * General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  29  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  30  * 02111-1307, USA.
  31  */
  32
  33 #include <zebra.h>
  34
  35 #include "thread.h"
  36 #include "memory.h"
  37 #include "linklist.h"
  38 #include "prefix.h"
  39 #include "if.h"
  40 #include "table.h"
  41 #include "sockunion.h"
  42 #include "stream.h"
  43 #include "log.h"
  44 #include "sockopt.h"
  45 #include "checksum.h"
  46 #include "vty.h"
  47 #include "md5.h"
  48
  49 #include "eigrpd/eigrp_structs.h"
  50 #include "eigrpd/eigrpd.h"
  51 #include "eigrpd/eigrp_interface.h"
  52 #include "eigrpd/eigrp_neighbor.h"
  53 #include "eigrpd/eigrp_packet.h"
  54 #include "eigrpd/eigrp_zebra.h"
  55 #include "eigrpd/eigrp_vty.h"
  56 #include "eigrpd/eigrp_dump.h"
  57 #include "eigrpd/eigrp_macros.h"
  58
  59 /* Packet Type String. */
  60 static const struct message eigrp_general_tlv_type_str[] =
  61 {
  62   { EIGRP_TLV_PARAMETER,        "PARAMETER"             },
  63   { EIGRP_TLV_AUTH,             "AUTH"                  },
  64   { EIGRP_TLV_SEQ,              "SEQ"                   },
  65   { EIGRP_TLV_SW_VERSION,       "SW_VERSION"            },
  66   { EIGRP_TLV_NEXT_MCAST_SEQ,   "NEXT_MCAST_SEQ"        },
  67   { EIGRP_TLV_PEER_TERMINATION, "PEER_TERMINATION"      },
  68   { EIGRP_TLV_PEER_MTRLIST,     "PEER_MTRLIST"          },
  69   { EIGRP_TLV_PEER_TIDLIST,     "PEER_TIDLIST"          },
  70 };
  71
  72 static const size_t eigrp_general_tlv_type_str_max = sizeof(eigrp_general_tlv_type_str) /
  73   sizeof(eigrp_general_tlv_type_str[0]);
  74
  75
  76 /*
  77  * @fn eigrp_hello_timer
  78  *
  79  * @param[in]   thread  current execution thread timer is associated with
  80  *
  81  * @return int  always returns 0
  82  *
  83  * @par
  84  * Called once per "hello" time interval, default 5 seconds
  85  * Sends hello packet via multicast for all interfaces eigrp
  86  * is configured for
  87  */
  88 int
  89 eigrp_hello_timer (struct thread *thread)
  90 {
  91   struct eigrp_interface *ei;
  92
  93   ei = THREAD_ARG(thread);
  94   ei->t_hello = NULL;
  95
  96   if (IS_DEBUG_EIGRP(0, TIMERS))
  97     zlog_debug ("Start Hello Timer (%s) Expire [%u]",
  98                 IF_NAME(ei), EIGRP_IF_PARAM(ei, v_hello));
  99
 100   /* Sending hello packet. */
 101   eigrp_hello_send(ei, EIGRP_HELLO_NORMAL, NULL);
 102
 103   /* Hello timer set. */
 104   ei->t_hello = NULL;
 105   thread_add_timer(master, eigrp_hello_timer, ei, EIGRP_IF_PARAM(ei, v_hello),
 106                    &ei->t_hello);
 107
 108   return 0;
 109 }
 110
 111 /**
 112  * @fn eigrp_hello_parameter_decode
 113  *
 114  * @param[in]           nbr     neighbor the ACK should be sent to
 115  * @param[in]           param   pointer packet TLV is stored to
 116  *
 117  * @return u_int16_t    number of bytes added to packet stream
 118  *
 119  * @par
 120  * Encode Parameter TLV, used to convey metric weights and the hold time.
 121  *
 122  * @usage
 123  * Note the addition of K6 for the new extended metrics, and does not apply to
 124  * older TLV packet formats.
 125  */
 126 static void
 127 eigrp_hello_parameter_decode (struct eigrp_neighbor *nbr,
 128                               struct eigrp_tlv_hdr_type *tlv)
 129 {
 130   struct eigrp *eigrp = nbr->ei->eigrp;
 131   struct TLV_Parameter_Type *param = (struct TLV_Parameter_Type *)tlv;
 132
 133   /* copy over the values passed in by the neighbor */
 134   nbr->K1 = param->K1;
 135   nbr->K2 = param->K2;
 136   nbr->K3 = param->K3;
 137   nbr->K4 = param->K4;
 138   nbr->K5 = param->K5;
 139   nbr->K6 = param->K6;
 140   nbr->v_holddown = ntohs(param->hold_time);
 141
 142   /*
 143    * Check K1-K5 have the correct values to be able to become neighbors
 144    * K6 does not have to match
 145    */
 146   if ((eigrp->k_values[0] == nbr->K1) &&
 147       (eigrp->k_values[1] == nbr->K2) &&
 148       (eigrp->k_values[2] == nbr->K3) &&
 149       (eigrp->k_values[3] == nbr->K4) &&
 150       (eigrp->k_values[4] == nbr->K5))
 151     {
 152
 153       if (eigrp_nbr_state_get(nbr) == EIGRP_NEIGHBOR_DOWN)
 154         {
 155           zlog_info("Neighbor %s (%s) is pending: new adjacency",
 156                     inet_ntoa(nbr->src), ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT));
 157
 158           /* Expedited hello sent */
 159           eigrp_hello_send(nbr->ei, EIGRP_HELLO_NORMAL, NULL);
 160
 161           //     if(ntohl(nbr->ei->address->u.prefix4.s_addr) > ntohl(nbr->src.s_addr))
 162           eigrp_update_send_init(nbr);
 163
 164           eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING);
 165         }
 166     }
 167   else
 168     {
 169       if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN)
 170         {
 171           if ((param->K1 & param->K2 & param->K3 & param->K4 & param->K5) == 255)
 172             {
 173               zlog_info ("Neighbor %s (%s) is down: Interface PEER-TERMINATION received",
 174                          inet_ntoa (nbr->src),ifindex2ifname (nbr->ei->ifp->ifindex, VRF_DEFAULT));
 175               eigrp_nbr_delete (nbr);
 176             }
 177           else
 178             {
 179               zlog_info ("Neighbor %s (%s) going down: Kvalue mismatch",
 180                          inet_ntoa (nbr->src),ifindex2ifname (nbr->ei->ifp->ifindex, VRF_DEFAULT));
 181               eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN);
 182             }
 183         }
 184     }
 185 }
 186
 187 static u_char
 188 eigrp_hello_authentication_decode(struct stream *s, struct eigrp_tlv_hdr_type *tlv_header,
 189                                   struct eigrp_neighbor *nbr)
 190 {
 191   struct TLV_MD5_Authentication_Type *md5;
 192
 193   md5 = (struct TLV_MD5_Authentication_Type *) tlv_header;
 194
 195   if(md5->auth_type == EIGRP_AUTH_TYPE_MD5)
 196     return eigrp_check_md5_digest(s, md5, nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 197   else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256)
 198     return eigrp_check_sha256_digest(s, (struct TLV_SHA256_Authentication_Type *)tlv_header,
 199                                      nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 200
 201   return 0;
 202 }
 203
 204 /**
 205  * @fn eigrp_sw_version_decode
 206  *
 207  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 208  * @param[in]           param   pointer to TLV software version information
 209  *
 210  * @return void
 211  *
 212  * @par
 213  * Read the software version in the specified location.
 214  * This consists of two bytes of OS version, and two bytes of EIGRP
 215  * revision number.
 216  */
 217 static void
 218 eigrp_sw_version_decode (struct eigrp_neighbor *nbr,
 219                          struct eigrp_tlv_hdr_type *tlv)
 220 {
 221   struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv;
 222
 223   nbr->os_rel_major = version->vender_major;
 224   nbr->os_rel_minor = version->vender_minor;
 225   nbr->tlv_rel_major = version->eigrp_major;
 226   nbr->tlv_rel_minor = version->eigrp_minor;
 227   return;
 228 }
 229
 230 /**
 231  * @fn eigrp_peer_termination_decode
 232  *
 233  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 234  * @param[in]           tlv     pointer to TLV software version information
 235  *
 236  * @return void
 237  *
 238  * @par
 239  * Read the address in the TLV and match to out address. If
 240  * a match is found, move the sending neighbor to the down state. If
 241  * out address is not in the TLV, then ignore the peer termination
 242  */
 243 static void
 244 eigrp_peer_termination_decode (struct eigrp_neighbor *nbr,
 245                                struct eigrp_tlv_hdr_type *tlv)
 246 {
 247   struct TLV_Peer_Termination_type *param = (struct TLV_Peer_Termination_type *)tlv;
 248
 249   uint32_t my_ip = nbr->ei->address->u.prefix4.s_addr;
 250   uint32_t received_ip = param->neighbor_ip;
 251
 252   if(my_ip == received_ip)
 253     {
 254       zlog_info ("Neighbor %s (%s) is down: Peer Termination received",
 255                  inet_ntoa (nbr->src),ifindex2ifname (nbr->ei->ifp->ifindex, VRF_DEFAULT));
 256       /* set neighbor to DOWN */
 257       nbr->state = EIGRP_NEIGHBOR_DOWN;
 258       /* delete neighbor */
 259       eigrp_nbr_delete (nbr);
 260     }
 261 }
 262
 263 /**
 264  * @fn eigrp_peer_termination_encode
 265  *
 266  * @param[in,out]   s             packet stream TLV is stored to
 267  * @param[in]           nbr_addr  pointer to neighbor address for Peer Termination TLV
 268  *
 269  * @return u_int16_t    number of bytes added to packet stream
 270  *
 271  * @par
 272  * Function used to encode Peer Termination TLV to Hello packet.
 273  */
 274 static u_int16_t
 275 eigrp_peer_termination_encode (struct stream *s, struct in_addr *nbr_addr)
 276 {
 277   u_int16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 278
 279   /* fill in type and length */
 280   stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 281   stream_putw(s, length);
 282
 283   /* fill in unknown field 0x04 */
 284   stream_putc(s, 0x04);
 285
 286   /* finally neighbor IP address */
 287   stream_put_ipv4(s, nbr_addr->s_addr);
 288
 289   return(length);
 290 }
 291
 292 /*
 293  * @fn eigrp_hello_receive
 294  *
 295  * @param[in]   eigrp           eigrp routing process
 296  * @param[in]   iph             pointer to ip header
 297  * @param[in]   eigrph          pointer to eigrp header
 298  * @param[in]   s               input ip stream
 299  * @param[in]   ei              eigrp interface packet arrived on
 300  * @param[in]   size            size of eigrp packet
 301  *
 302  * @return void
 303  *
 304  * @par
 305  * This is the main worker function for processing hello packets. It
 306  * will validate the peer associated with the src ip address of the ip
 307  * header, and then decode each of the general TLVs which the packet
 308  * may contain.
 309  *
 310  * @usage
 311  * Not all TLVs are current decoder.  This is a work in progress..
 312  */
 313 void
 314 eigrp_hello_receive (struct eigrp *eigrp, struct ip *iph, struct eigrp_header *eigrph,
 315                      struct stream *s, struct eigrp_interface *ei, int size)
 316 {
 317   struct eigrp_tlv_hdr_type *tlv_header;
 318   struct eigrp_neighbor *nbr;
 319   uint16_t      type;
 320   uint16_t      length;
 321
 322   /* get neighbor struct */
 323   nbr = eigrp_nbr_get(ei, eigrph, iph);
 324
 325   /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 326   assert(nbr);
 327
 328   if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 329     zlog_debug("Processing Hello size[%u] int(%s) nbr(%s)",
 330                size, ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT),
 331                inet_ntoa(nbr->src));
 332
 333   size -= EIGRP_HEADER_LEN;
 334   if (size < 0)
 335     return;
 336
 337   tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 338
 339   do {
 340     type = ntohs(tlv_header->type);
 341     length = ntohs(tlv_header->length);
 342
 343     if ((length > 0) && (length <= size))
 344       {
 345         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 346           zlog_debug("  General TLV(%s)", LOOKUP(eigrp_general_tlv_type_str, type));
 347
 348         // determine what General TLV is being processed
 349         switch (type)
 350           {
 351           case EIGRP_TLV_PARAMETER:
 352             eigrp_hello_parameter_decode(nbr, tlv_header);
 353             break;
 354           case EIGRP_TLV_AUTH:
 355             {
 356               if(eigrp_hello_authentication_decode(s,tlv_header,nbr) == 0)
 357                 return;
 358               else
 359                 break;
 360               break;
 361             }
 362           case EIGRP_TLV_SEQ:
 363             break;
 364           case EIGRP_TLV_SW_VERSION:
 365             eigrp_sw_version_decode(nbr, tlv_header);
 366             break;
 367          case EIGRP_TLV_NEXT_MCAST_SEQ:
 368            break;
 369           case EIGRP_TLV_PEER_TERMINATION:
 370             eigrp_peer_termination_decode(nbr, tlv_header);
 371             break;
 372           case EIGRP_TLV_PEER_MTRLIST:
 373          case EIGRP_TLV_PEER_TIDLIST:
 374            break;
 375           default:
 376             break;
 377           }
 378       }
 379
 380     tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header) + length);
 381     size -= length;
 382
 383   } while (size > 0);
 384
 385
 386   /*If received packet is hello with Parameter TLV*/
 387   if (ntohl(eigrph->ack) == 0)
 388     {
 389       /* increment statistics. */
 390       ei->hello_in++;
 391       eigrp_nbr_state_update(nbr);
 392
 393     }
 394
 395   if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 396     zlog_debug("Hello Packet received from %s", inet_ntoa(nbr->src));
 397 }
 398
 399 /**
 400  * @fn eigrp_sw_version_encode
 401  *
 402  * @param[in,out]       s       packet stream TLV is stored to
 403  *
 404  * @return u_int16_t    number of bytes added to packet stream
 405  *
 406  * @par
 407  * Store the software version in the specified location.
 408  * This consists of two bytes of OS version, and two bytes of EIGRP
 409  * revision number.
 410  */
 411 static u_int16_t
 412 eigrp_sw_version_encode (struct stream *s)
 413 {
 414   u_int16_t length = EIGRP_TLV_SW_VERSION_LEN;
 415
 416   // setup the tlv fields
 417   stream_putw(s, EIGRP_TLV_SW_VERSION);
 418   stream_putw(s, length);
 419
 420   // encode the version of quagga we're running
 421   // DVS: need to figure out a cleaner way to do this
 422   stream_putc(s, 0);            //!< major os version
 423   stream_putc(s, 99);           //!< minor os version
 424
 425   /* and the core eigrp version */
 426   stream_putc(s, EIGRP_MAJOR_VERSION);
 427   stream_putc(s, EIGRP_MINOR_VERSION);
 428
 429   return(length);
 430 }
 431
 432 /**
 433  * @fn eigrp_tidlist_encode
 434  *
 435  * @param[in,out]       s       packet stream TLV is stored to
 436  *
 437  * @return void
 438  *
 439  * @par
 440  * If doing mutli-topology, then store the supported TID list.
 441  * This is currently a place holder function
 442  */
 443 static u_int16_t
 444 eigrp_tidlist_encode (struct stream *s)
 445 {
 446   //u_int16_t length = EIGRP_TLV_SW_VERSION_LEN;
 447   return 0;
 448 }
 449
 450 /**
 451  * @fn eigrp_sequence_encode
 452  *
 453  * @param[in,out]       s       packet stream TLV is stored to
 454  *
 455  * @return u_int16_t    number of bytes added to packet stream
 456  *
 457  * @par
 458  * Part of conditional receive process
 459  *
 460  */
 461 static u_int16_t
 462 eigrp_sequence_encode (struct stream *s)
 463 {
 464   u_int16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 465   struct eigrp *eigrp;
 466   struct eigrp_interface *ei;
 467   struct listnode *node, *node2, *nnode2;
 468   struct eigrp_neighbor *nbr;
 469   size_t backup_end, size_end;
 470   int found;
 471
 472   eigrp = eigrp_lookup ();
 473   if (eigrp == NULL)
 474     {
 475       return 0;
 476     }
 477
 478   // add in the parameters TLV
 479   backup_end = stream_get_endp(s);
 480   stream_putw(s, EIGRP_TLV_SEQ);
 481   size_end = s->endp;
 482   stream_putw(s, 0x0000);
 483   stream_putc(s, IPV4_MAX_BYTELEN);
 484
 485   found = 0;
 486   for (ALL_LIST_ELEMENTS_RO (eigrp->eiflist, node, ei))
 487     {
 488       for (ALL_LIST_ELEMENTS (ei->nbrs, node2, nnode2, nbr))
 489         {
 490           if(nbr->multicast_queue->count > 0)
 491             {
 492               length += (u_int16_t) stream_put_ipv4(s,nbr->src.s_addr);
 493               found = 1;
 494             }
 495         }
 496     }
 497
 498   if(found == 0)
 499     {
 500       stream_set_endp(s,backup_end);
 501       return 0;
 502     }
 503
 504   backup_end = stream_get_endp (s);
 505   stream_set_endp (s,size_end);
 506   stream_putw (s, length);
 507   stream_set_endp (s, backup_end);
 508
 509   return length;
 510 }
 511
 512 /**
 513  * @fn eigrp_sequence_encode
 514  *
 515  * @param[in,out]       s       packet stream TLV is stored to
 516  *
 517  * @return u_int16_t    number of bytes added to packet stream
 518  *
 519  * @par
 520  * Part of conditional receive process
 521  *
 522  */
 523 static u_int16_t
 524 eigrp_next_sequence_encode (struct stream *s)
 525 {
 526   u_int16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 527   struct eigrp *eigrp;
 528
 529   eigrp = eigrp_lookup ();
 530   if (eigrp == NULL)
 531     {
 532       return 0;
 533     }
 534
 535   // add in the parameters TLV
 536   stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 537   stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 538   stream_putl(s,eigrp->sequence_number+1);
 539
 540   return length;
 541 }
 542
 543 /**
 544  * @fn eigrp_hello_parameter_encode
 545  *
 546  * @param[in]           ei      pointer to interface hello packet came in on
 547  * @param[in,out]       s       packet stream TLV is stored to
 548  *
 549  * @return u_int16_t    number of bytes added to packet stream
 550  *
 551  * @par
 552  * Encode Parameter TLV, used to convey metric weights and the hold time.
 553  *
 554  * @usage
 555  * Note the addition of K6 for the new extended metrics, and does not apply to
 556  * older TLV packet formats.
 557  */
 558 static u_int16_t
 559 eigrp_hello_parameter_encode (struct eigrp_interface *ei, struct stream *s, u_char flags)
 560 {
 561   u_int16_t length = EIGRP_TLV_PARAMETER_LEN;
 562
 563   // add in the parameters TLV
 564   stream_putw(s, EIGRP_TLV_PARAMETER);
 565   stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 566
 567   //if graceful shutdown is needed to be announced, send all 255 in K values
 568   if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 569     {
 570       stream_putc(s, 0xff); /* K1 */
 571       stream_putc(s, 0xff); /* K2 */
 572       stream_putc(s, 0xff); /* K3 */
 573       stream_putc(s, 0xff); /* K4 */
 574       stream_putc(s, 0xff); /* K5 */
 575       stream_putc(s, 0xff); /* K6 */
 576     }
 577   else // set k values
 578     {
 579       stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 580       stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 581       stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 582       stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 583       stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 584       stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 585     }
 586
 587   // and set hold time value..
 588   stream_putw(s, IF_DEF_PARAMS(ei->ifp)->v_wait);
 589
 590   return length;
 591 }
 592
 593 /**
 594  * @fn eigrp_hello_encode
 595  *
 596  * @param[in]           ei      pointer to interface hello packet came in on
 597  * @param[in]           s       packet stream TLV is stored to
 598  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 599  * @param[in]           flags  type of hello packet
 600  * @param[in]           nbr_addr  pointer to neighbor address for Peer Termination TLV
 601  *
 602  * @return eigrp_packet         pointer initialize hello packet
 603  *
 604  * @par
 605  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 606  *
 607  */
 608 static struct eigrp_packet *
 609 eigrp_hello_encode (struct eigrp_interface *ei, in_addr_t addr, u_int32_t ack,
 610                     u_char flags, struct in_addr *nbr_addr)
 611 {
 612   struct eigrp_packet *ep;
 613   u_int16_t length = EIGRP_HEADER_LEN;
 614
 615   // allocate a new packet to be sent
 616   ep = eigrp_packet_new(ei->ifp->mtu);
 617
 618   if (ep)
 619     {
 620       // encode common header feilds
 621       eigrp_packet_header_init(EIGRP_OPC_HELLO, ei, ep->s, 0, 0, ack);
 622
 623       // encode Authentication TLV
 624       if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_MD5) &&
 625          (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 626         {
 627           length += eigrp_add_authTLV_MD5_to_stream(ep->s,ei);
 628         }
 629       else if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_SHA256) &&
 630               (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 631         {
 632           length += eigrp_add_authTLV_SHA256_to_stream(ep->s,ei);
 633         }
 634
 635       /* encode appropriate parameters to Hello packet */
 636       if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 637         length += eigrp_hello_parameter_encode(ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 638       else
 639         length += eigrp_hello_parameter_encode(ei, ep->s, EIGRP_HELLO_NORMAL);
 640
 641       // figure out the version of code we're running
 642       length += eigrp_sw_version_encode(ep->s);
 643
 644       if(flags & EIGRP_HELLO_ADD_SEQUENCE)
 645         {
 646           length += eigrp_sequence_encode(ep->s);
 647           length += eigrp_next_sequence_encode(ep->s);
 648         }
 649
 650       // add in the TID list if doing multi-topology
 651       length += eigrp_tidlist_encode(ep->s);
 652
 653       /* encode Peer Termination TLV if needed */
 654       if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 655         length += eigrp_peer_termination_encode(ep->s, nbr_addr);
 656
 657       // Set packet length
 658       ep->length = length;
 659
 660       // set soruce address for the hello packet
 661       ep->dst.s_addr = addr;
 662
 663       if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_MD5) &&
 664          (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 665         {
 666           eigrp_make_md5_digest(ei,ep->s, EIGRP_AUTH_BASIC_HELLO_FLAG);
 667         }
 668       else if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_SHA256) &&
 669               (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 670         {
 671           eigrp_make_sha256_digest(ei,ep->s, EIGRP_AUTH_BASIC_HELLO_FLAG);
 672         }
 673
 674       // EIGRP Checksum
 675       eigrp_packet_checksum(ei, ep->s, length);
 676     }
 677
 678   return(ep);
 679 }
 680
 681 /**
 682  * @fn eigrp_hello_send
 683  *
 684  * @param[in]           nbr     neighbor the ACK should be sent to
 685  *
 686  * @return void
 687  *
 688  * @par
 689  *  Send (unicast) a hello packet with the destination address
 690  *  associated with the neighbor.  The eigrp header ACK feild will be
 691  *  updated to the neighbor's sequence number to acknolodge any
 692  *  outstanding packets
 693  */
 694 void
 695 eigrp_hello_send_ack (struct eigrp_neighbor *nbr)
 696 {
 697   struct eigrp_packet *ep;
 698
 699   /* if packet succesfully created, add it to the interface queue */
 700   ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr, nbr->recv_sequence_number, EIGRP_HELLO_NORMAL, NULL);
 701
 702   if (ep)
 703     {
 704       if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 705         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%s]",
 706                    nbr->recv_sequence_number, inet_ntoa(nbr->src));
 707
 708       /* Add packet to the top of the interface output queue*/
 709       eigrp_fifo_push_head(nbr->ei->obuf, ep);
 710
 711       /* Hook thread to write packet. */
 712       if (nbr->ei->on_write_q == 0)
 713         {
 714           listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 715           nbr->ei->on_write_q = 1;
 716         }
 717       thread_add_write(master, eigrp_write, nbr->ei->eigrp, nbr->ei->eigrp->fd,
 718                        &nbr->ei->eigrp->t_write);
 719     }
 720 }
 721
 722 /**
 723  * @fn eigrp_hello_send
 724  *
 725  * @param[in]           ei      pointer to interface hello should be sent
 726  * @param[in]           flags type of hello packet
 727  * @param[in]           nbr_addr  pointer to neighbor address for Peer Termination TLV
 728  *
 729  * @return void
 730  *
 731  * @par
 732  * Build and enqueue a generic (multicast) periodic hello packet for
 733  * sending.  If no packets are currently queues, the packet will be
 734  * sent immadiatly
 735  */
 736 void
 737 eigrp_hello_send (struct eigrp_interface *ei, u_char flags, struct in_addr *nbr_addr)
 738 {
 739   struct eigrp_packet *ep = NULL;
 740
 741   /* If this is passive interface, do not send EIGRP Hello.
 742      if ((EIGRP_IF_PASSIVE_STATUS (ei) == EIGRP_IF_PASSIVE) ||
 743      (ei->type != EIGRP_IFTYPE_NBMA))
 744      return;
 745   */
 746
 747   if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 748     zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 749
 750   /* if packet was succesfully created, then add it to the interface queue */
 751   ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags, nbr_addr);
 752
 753   if (ep)
 754     {
 755       // Add packet to the top of the interface output queue
 756       eigrp_fifo_push_head(ei->obuf, ep);
 757
 758       /* Hook thread to write packet. */
 759       if (ei->on_write_q == 0)
 760         {
 761           listnode_add(ei->eigrp->oi_write_q, ei);
 762           ei->on_write_q = 1;
 763         }
 764
 765       if (ei->eigrp->t_write == NULL)
 766         {
 767           if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 768             {
 769               thread_execute(master, eigrp_write, ei->eigrp, ei->eigrp->fd);
 770             }
 771           else
 772             {
 773               thread_add_write(master, eigrp_write, ei->eigrp, ei->eigrp->fd,
 774                                &ei->eigrp->t_write);
 775             }
 776         }
 777     }
 778 }