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 along
  28  * with this program; see the file COPYING; if not, write to the Free Software
  29  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  30  */
  31
  32 #include <zebra.h>
  33
  34 #include "thread.h"
  35 #include "memory.h"
  36 #include "linklist.h"
  37 #include "prefix.h"
  38 #include "if.h"
  39 #include "table.h"
  40 #include "sockunion.h"
  41 #include "stream.h"
  42 #include "log.h"
  43 #include "sockopt.h"
  44 #include "checksum.h"
  45 #include "vty.h"
  46 #include "md5.h"
  47
  48 #include "eigrpd/eigrp_structs.h"
  49 #include "eigrpd/eigrpd.h"
  50 #include "eigrpd/eigrp_interface.h"
  51 #include "eigrpd/eigrp_neighbor.h"
  52 #include "eigrpd/eigrp_packet.h"
  53 #include "eigrpd/eigrp_zebra.h"
  54 #include "eigrpd/eigrp_vty.h"
  55 #include "eigrpd/eigrp_dump.h"
  56 #include "eigrpd/eigrp_macros.h"
  57
  58 /* Packet Type String. */
  59 static const struct message eigrp_general_tlv_type_str[] =
  60 {
  61   { EIGRP_TLV_PARAMETER,        "PARAMETER"             },
  62   { EIGRP_TLV_AUTH,             "AUTH"                  },
  63   { EIGRP_TLV_SEQ,              "SEQ"                   },
  64   { EIGRP_TLV_SW_VERSION,       "SW_VERSION"            },
  65   { EIGRP_TLV_NEXT_MCAST_SEQ,   "NEXT_MCAST_SEQ"        },
  66   { EIGRP_TLV_PEER_TERMINATION, "PEER_TERMINATION"      },
  67   { EIGRP_TLV_PEER_MTRLIST,     "PEER_MTRLIST"          },
  68   { EIGRP_TLV_PEER_TIDLIST,     "PEER_TIDLIST"          },
  69   { 0 }
  70 };
  71
  72
  73 /*
  74  * @fn eigrp_hello_timer
  75  *
  76  * @param[in]   thread  current execution thread timer is associated with
  77  *
  78  * @return int  always returns 0
  79  *
  80  * @par
  81  * Called once per "hello" time interval, default 5 seconds
  82  * Sends hello packet via multicast for all interfaces eigrp
  83  * is configured for
  84  */
  85 int
  86 eigrp_hello_timer (struct thread *thread)
  87 {
  88   struct eigrp_interface *ei;
  89
  90   ei = THREAD_ARG(thread);
  91   ei->t_hello = NULL;
  92
  93   if (IS_DEBUG_EIGRP(0, TIMERS))
  94     zlog_debug ("Start Hello Timer (%s) Expire [%u]",
  95                 IF_NAME(ei), EIGRP_IF_PARAM(ei, v_hello));
  96
  97   /* Sending hello packet. */
  98   eigrp_hello_send(ei, EIGRP_HELLO_NORMAL, NULL);
  99
 100   /* Hello timer set. */
 101   ei->t_hello = NULL;
 102   thread_add_timer(master, eigrp_hello_timer, ei, EIGRP_IF_PARAM(ei, v_hello),
 103                    &ei->t_hello);
 104
 105   return 0;
 106 }
 107
 108 /**
 109  * @fn eigrp_hello_parameter_decode
 110  *
 111  * @param[in]           nbr     neighbor the ACK should be sent to
 112  * @param[in]           param   pointer packet TLV is stored to
 113  *
 114  * @return u_int16_t    number of bytes added to packet stream
 115  *
 116  * @par
 117  * Encode Parameter TLV, used to convey metric weights and the hold time.
 118  *
 119  * @usage
 120  * Note the addition of K6 for the new extended metrics, and does not apply to
 121  * older TLV packet formats.
 122  */
 123 static struct eigrp_neighbor *
 124 eigrp_hello_parameter_decode (struct eigrp_neighbor *nbr,
 125                               struct eigrp_tlv_hdr_type *tlv)
 126 {
 127   struct eigrp *eigrp = nbr->ei->eigrp;
 128   struct TLV_Parameter_Type *param = (struct TLV_Parameter_Type *)tlv;
 129
 130   /* copy over the values passed in by the neighbor */
 131   nbr->K1 = param->K1;
 132   nbr->K2 = param->K2;
 133   nbr->K3 = param->K3;
 134   nbr->K4 = param->K4;
 135   nbr->K5 = param->K5;
 136   nbr->K6 = param->K6;
 137   nbr->v_holddown = ntohs(param->hold_time);
 138
 139   /*
 140    * Check K1-K5 have the correct values to be able to become neighbors
 141    * K6 does not have to match
 142    */
 143   if ((eigrp->k_values[0] == nbr->K1) &&
 144       (eigrp->k_values[1] == nbr->K2) &&
 145       (eigrp->k_values[2] == nbr->K3) &&
 146       (eigrp->k_values[3] == nbr->K4) &&
 147       (eigrp->k_values[4] == nbr->K5))
 148     {
 149
 150       if (eigrp_nbr_state_get(nbr) == EIGRP_NEIGHBOR_DOWN)
 151         {
 152           zlog_info("Neighbor %s (%s) is pending: new adjacency",
 153                     inet_ntoa(nbr->src), ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT));
 154
 155           /* Expedited hello sent */
 156           eigrp_hello_send(nbr->ei, EIGRP_HELLO_NORMAL, NULL);
 157
 158           //     if(ntohl(nbr->ei->address->u.prefix4.s_addr) > ntohl(nbr->src.s_addr))
 159           eigrp_update_send_init(nbr);
 160
 161           eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING);
 162         }
 163     }
 164   else
 165     {
 166       if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN)
 167         {
 168           if ((param->K1 & param->K2 & param->K3 & param->K4 & param->K5) == 255)
 169             {
 170               zlog_info ("Neighbor %s (%s) is down: Interface PEER-TERMINATION received",
 171                          inet_ntoa (nbr->src),ifindex2ifname (nbr->ei->ifp->ifindex, VRF_DEFAULT));
 172               eigrp_nbr_delete (nbr);
 173               return NULL;
 174             }
 175           else
 176             {
 177               zlog_info ("Neighbor %s (%s) going down: Kvalue mismatch",
 178                          inet_ntoa (nbr->src),ifindex2ifname (nbr->ei->ifp->ifindex, VRF_DEFAULT));
 179               eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN);
 180             }
 181         }
 182     }
 183
 184   return nbr;
 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),
 256                  ifindex2ifname (nbr->ei->ifp->ifindex, VRF_DEFAULT));
 257       /* set neighbor to DOWN */
 258       nbr->state = EIGRP_NEIGHBOR_DOWN;
 259       /* delete neighbor */
 260       eigrp_nbr_delete (nbr);
 261     }
 262 }
 263
 264 /**
 265  * @fn eigrp_peer_termination_encode
 266  *
 267  * @param[in,out]   s             packet stream TLV is stored to
 268  * @param[in]           nbr_addr  pointer to neighbor address for Peer Termination TLV
 269  *
 270  * @return u_int16_t    number of bytes added to packet stream
 271  *
 272  * @par
 273  * Function used to encode Peer Termination TLV to Hello packet.
 274  */
 275 static u_int16_t
 276 eigrp_peer_termination_encode (struct stream *s, struct in_addr *nbr_addr)
 277 {
 278   u_int16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 279
 280   /* fill in type and length */
 281   stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 282   stream_putw(s, length);
 283
 284   /* fill in unknown field 0x04 */
 285   stream_putc(s, 0x04);
 286
 287   /* finally neighbor IP address */
 288   stream_put_ipv4(s, nbr_addr->s_addr);
 289
 290   return(length);
 291 }
 292
 293 /*
 294  * @fn eigrp_hello_receive
 295  *
 296  * @param[in]   eigrp           eigrp routing process
 297  * @param[in]   iph             pointer to ip header
 298  * @param[in]   eigrph          pointer to eigrp header
 299  * @param[in]   s               input ip stream
 300  * @param[in]   ei              eigrp interface packet arrived on
 301  * @param[in]   size            size of eigrp packet
 302  *
 303  * @return void
 304  *
 305  * @par
 306  * This is the main worker function for processing hello packets. It
 307  * will validate the peer associated with the src ip address of the ip
 308  * header, and then decode each of the general TLVs which the packet
 309  * may contain.
 310  *
 311  * @usage
 312  * Not all TLVs are current decoder.  This is a work in progress..
 313  */
 314 void
 315 eigrp_hello_receive (struct eigrp *eigrp, struct ip *iph, struct eigrp_header *eigrph,
 316                      struct stream *s, struct eigrp_interface *ei, int size)
 317 {
 318   struct eigrp_tlv_hdr_type *tlv_header;
 319   struct eigrp_neighbor *nbr;
 320   uint16_t      type;
 321   uint16_t      length;
 322
 323   /* get neighbor struct */
 324   nbr = eigrp_nbr_get(ei, eigrph, iph);
 325
 326   /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 327   assert(nbr);
 328
 329   if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 330     zlog_debug("Processing Hello size[%u] int(%s) nbr(%s)",
 331                size, ifindex2ifname(nbr->ei->ifp->ifindex, VRF_DEFAULT),
 332                inet_ntoa(nbr->src));
 333
 334   size -= EIGRP_HEADER_LEN;
 335   if (size < 0)
 336     return;
 337
 338   tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 339
 340   do {
 341     type = ntohs(tlv_header->type);
 342     length = ntohs(tlv_header->length);
 343
 344     if ((length > 0) && (length <= size))
 345       {
 346         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 347           zlog_debug("  General TLV(%s)", lookup_msg(eigrp_general_tlv_type_str, type, NULL));
 348
 349         // determine what General TLV is being processed
 350         switch (type)
 351           {
 352           case EIGRP_TLV_PARAMETER:
 353             nbr = eigrp_hello_parameter_decode(nbr, tlv_header);
 354             if (!nbr)
 355               return;
 356             break;
 357           case EIGRP_TLV_AUTH:
 358             {
 359               if(eigrp_hello_authentication_decode(s,tlv_header,nbr) == 0)
 360                 return;
 361               else
 362                 break;
 363               break;
 364             }
 365           case EIGRP_TLV_SEQ:
 366             break;
 367           case EIGRP_TLV_SW_VERSION:
 368             eigrp_sw_version_decode(nbr, tlv_header);
 369             break;
 370           case EIGRP_TLV_NEXT_MCAST_SEQ:
 371             break;
 372           case EIGRP_TLV_PEER_TERMINATION:
 373             eigrp_peer_termination_decode(nbr, tlv_header);
 374             return;
 375             break;
 376           case EIGRP_TLV_PEER_MTRLIST:
 377           case EIGRP_TLV_PEER_TIDLIST:
 378             break;
 379           default:
 380             break;
 381           }
 382       }
 383
 384     tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header) + length);
 385     size -= length;
 386
 387   } while (size > 0);
 388
 389
 390   /*If received packet is hello with Parameter TLV*/
 391   if (ntohl(eigrph->ack) == 0)
 392     {
 393       /* increment statistics. */
 394       ei->hello_in++;
 395       if (nbr)
 396         eigrp_nbr_state_update(nbr);
 397
 398     }
 399
 400   if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 401     zlog_debug("Hello Packet received from %s", inet_ntoa(nbr->src));
 402 }
 403
 404 /**
 405  * @fn eigrp_sw_version_encode
 406  *
 407  * @param[in,out]       s       packet stream TLV is stored to
 408  *
 409  * @return u_int16_t    number of bytes added to packet stream
 410  *
 411  * @par
 412  * Store the software version in the specified location.
 413  * This consists of two bytes of OS version, and two bytes of EIGRP
 414  * revision number.
 415  */
 416 static u_int16_t
 417 eigrp_sw_version_encode (struct stream *s)
 418 {
 419   u_int16_t length = EIGRP_TLV_SW_VERSION_LEN;
 420
 421   // setup the tlv fields
 422   stream_putw(s, EIGRP_TLV_SW_VERSION);
 423   stream_putw(s, length);
 424
 425   // encode the version of quagga we're running
 426   // DVS: need to figure out a cleaner way to do this
 427   stream_putc(s, 0);            //!< major os version
 428   stream_putc(s, 99);           //!< minor os version
 429
 430   /* and the core eigrp version */
 431   stream_putc(s, EIGRP_MAJOR_VERSION);
 432   stream_putc(s, EIGRP_MINOR_VERSION);
 433
 434   return(length);
 435 }
 436
 437 /**
 438  * @fn eigrp_tidlist_encode
 439  *
 440  * @param[in,out]       s       packet stream TLV is stored to
 441  *
 442  * @return void
 443  *
 444  * @par
 445  * If doing mutli-topology, then store the supported TID list.
 446  * This is currently a place holder function
 447  */
 448 static u_int16_t
 449 eigrp_tidlist_encode (struct stream *s)
 450 {
 451   //u_int16_t length = EIGRP_TLV_SW_VERSION_LEN;
 452   return 0;
 453 }
 454
 455 /**
 456  * @fn eigrp_sequence_encode
 457  *
 458  * @param[in,out]       s       packet stream TLV is stored to
 459  *
 460  * @return u_int16_t    number of bytes added to packet stream
 461  *
 462  * @par
 463  * Part of conditional receive process
 464  *
 465  */
 466 static u_int16_t
 467 eigrp_sequence_encode (struct stream *s)
 468 {
 469   u_int16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 470   struct eigrp *eigrp;
 471   struct eigrp_interface *ei;
 472   struct listnode *node, *node2, *nnode2;
 473   struct eigrp_neighbor *nbr;
 474   size_t backup_end, size_end;
 475   int found;
 476
 477   eigrp = eigrp_lookup ();
 478   if (eigrp == NULL)
 479     {
 480       return 0;
 481     }
 482
 483   // add in the parameters TLV
 484   backup_end = stream_get_endp(s);
 485   stream_putw(s, EIGRP_TLV_SEQ);
 486   size_end = s->endp;
 487   stream_putw(s, 0x0000);
 488   stream_putc(s, IPV4_MAX_BYTELEN);
 489
 490   found = 0;
 491   for (ALL_LIST_ELEMENTS_RO (eigrp->eiflist, node, ei))
 492     {
 493       for (ALL_LIST_ELEMENTS (ei->nbrs, node2, nnode2, nbr))
 494         {
 495           if(nbr->multicast_queue->count > 0)
 496             {
 497               length += (u_int16_t) stream_put_ipv4(s,nbr->src.s_addr);
 498               found = 1;
 499             }
 500         }
 501     }
 502
 503   if(found == 0)
 504     {
 505       stream_set_endp(s,backup_end);
 506       return 0;
 507     }
 508
 509   backup_end = stream_get_endp (s);
 510   stream_set_endp (s,size_end);
 511   stream_putw (s, length);
 512   stream_set_endp (s, backup_end);
 513
 514   return length;
 515 }
 516
 517 /**
 518  * @fn eigrp_sequence_encode
 519  *
 520  * @param[in,out]       s       packet stream TLV is stored to
 521  *
 522  * @return u_int16_t    number of bytes added to packet stream
 523  *
 524  * @par
 525  * Part of conditional receive process
 526  *
 527  */
 528 static u_int16_t
 529 eigrp_next_sequence_encode (struct stream *s)
 530 {
 531   u_int16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 532   struct eigrp *eigrp;
 533
 534   eigrp = eigrp_lookup ();
 535   if (eigrp == NULL)
 536     {
 537       return 0;
 538     }
 539
 540   // add in the parameters TLV
 541   stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 542   stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 543   stream_putl(s,eigrp->sequence_number+1);
 544
 545   return length;
 546 }
 547
 548 /**
 549  * @fn eigrp_hello_parameter_encode
 550  *
 551  * @param[in]           ei      pointer to interface hello packet came in on
 552  * @param[in,out]       s       packet stream TLV is stored to
 553  *
 554  * @return u_int16_t    number of bytes added to packet stream
 555  *
 556  * @par
 557  * Encode Parameter TLV, used to convey metric weights and the hold time.
 558  *
 559  * @usage
 560  * Note the addition of K6 for the new extended metrics, and does not apply to
 561  * older TLV packet formats.
 562  */
 563 static u_int16_t
 564 eigrp_hello_parameter_encode (struct eigrp_interface *ei, struct stream *s, u_char flags)
 565 {
 566   u_int16_t length = EIGRP_TLV_PARAMETER_LEN;
 567
 568   // add in the parameters TLV
 569   stream_putw(s, EIGRP_TLV_PARAMETER);
 570   stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 571
 572   //if graceful shutdown is needed to be announced, send all 255 in K values
 573   if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 574     {
 575       stream_putc(s, 0xff); /* K1 */
 576       stream_putc(s, 0xff); /* K2 */
 577       stream_putc(s, 0xff); /* K3 */
 578       stream_putc(s, 0xff); /* K4 */
 579       stream_putc(s, 0xff); /* K5 */
 580       stream_putc(s, 0xff); /* K6 */
 581     }
 582   else // set k values
 583     {
 584       stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 585       stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 586       stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 587       stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 588       stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 589       stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 590     }
 591
 592   // and set hold time value..
 593   stream_putw(s, IF_DEF_PARAMS(ei->ifp)->v_wait);
 594
 595   return length;
 596 }
 597
 598 /**
 599  * @fn eigrp_hello_encode
 600  *
 601  * @param[in]           ei      pointer to interface hello packet came in on
 602  * @param[in]           s       packet stream TLV is stored to
 603  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 604  * @param[in]           flags  type of hello packet
 605  * @param[in]           nbr_addr  pointer to neighbor address for Peer Termination TLV
 606  *
 607  * @return eigrp_packet         pointer initialize hello packet
 608  *
 609  * @par
 610  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 611  *
 612  */
 613 static struct eigrp_packet *
 614 eigrp_hello_encode (struct eigrp_interface *ei, in_addr_t addr, u_int32_t ack,
 615                     u_char flags, struct in_addr *nbr_addr)
 616 {
 617   struct eigrp_packet *ep;
 618   u_int16_t length = EIGRP_HEADER_LEN;
 619
 620   // allocate a new packet to be sent
 621   ep = eigrp_packet_new(ei->ifp->mtu);
 622
 623   if (ep)
 624     {
 625       // encode common header feilds
 626       eigrp_packet_header_init(EIGRP_OPC_HELLO, ei, ep->s, 0, 0, ack);
 627
 628       // encode Authentication TLV
 629       if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_MD5) &&
 630          (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 631         {
 632           length += eigrp_add_authTLV_MD5_to_stream(ep->s,ei);
 633         }
 634       else if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_SHA256) &&
 635               (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 636         {
 637           length += eigrp_add_authTLV_SHA256_to_stream(ep->s,ei);
 638         }
 639
 640       /* encode appropriate parameters to Hello packet */
 641       if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 642         length += eigrp_hello_parameter_encode(ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 643       else
 644         length += eigrp_hello_parameter_encode(ei, ep->s, EIGRP_HELLO_NORMAL);
 645
 646       // figure out the version of code we're running
 647       length += eigrp_sw_version_encode(ep->s);
 648
 649       if(flags & EIGRP_HELLO_ADD_SEQUENCE)
 650         {
 651           length += eigrp_sequence_encode(ep->s);
 652           length += eigrp_next_sequence_encode(ep->s);
 653         }
 654
 655       // add in the TID list if doing multi-topology
 656       length += eigrp_tidlist_encode(ep->s);
 657
 658       /* encode Peer Termination TLV if needed */
 659       if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 660         length += eigrp_peer_termination_encode(ep->s, nbr_addr);
 661
 662       // Set packet length
 663       ep->length = length;
 664
 665       // set soruce address for the hello packet
 666       ep->dst.s_addr = addr;
 667
 668       if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_MD5) &&
 669          (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 670         {
 671           eigrp_make_md5_digest(ei,ep->s, EIGRP_AUTH_BASIC_HELLO_FLAG);
 672         }
 673       else if((IF_DEF_PARAMS (ei->ifp)->auth_type == EIGRP_AUTH_TYPE_SHA256) &&
 674               (IF_DEF_PARAMS (ei->ifp)->auth_keychain != NULL))
 675         {
 676           eigrp_make_sha256_digest(ei,ep->s, EIGRP_AUTH_BASIC_HELLO_FLAG);
 677         }
 678
 679       // EIGRP Checksum
 680       eigrp_packet_checksum(ei, ep->s, length);
 681     }
 682
 683   return(ep);
 684 }
 685
 686 /**
 687  * @fn eigrp_hello_send
 688  *
 689  * @param[in]           nbr     neighbor the ACK should be sent to
 690  *
 691  * @return void
 692  *
 693  * @par
 694  *  Send (unicast) a hello packet with the destination address
 695  *  associated with the neighbor.  The eigrp header ACK feild will be
 696  *  updated to the neighbor's sequence number to acknolodge any
 697  *  outstanding packets
 698  */
 699 void
 700 eigrp_hello_send_ack (struct eigrp_neighbor *nbr)
 701 {
 702   struct eigrp_packet *ep;
 703
 704   /* if packet succesfully created, add it to the interface queue */
 705   ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr, nbr->recv_sequence_number, EIGRP_HELLO_NORMAL, NULL);
 706
 707   if (ep)
 708     {
 709       if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 710         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%s]",
 711                    nbr->recv_sequence_number, inet_ntoa(nbr->src));
 712
 713       /* Add packet to the top of the interface output queue*/
 714       eigrp_fifo_push_head(nbr->ei->obuf, ep);
 715
 716       /* Hook thread to write packet. */
 717       if (nbr->ei->on_write_q == 0)
 718         {
 719           listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 720           nbr->ei->on_write_q = 1;
 721         }
 722       thread_add_write(master, eigrp_write, nbr->ei->eigrp, nbr->ei->eigrp->fd,
 723                        &nbr->ei->eigrp->t_write);
 724     }
 725 }
 726
 727 /**
 728  * @fn eigrp_hello_send
 729  *
 730  * @param[in]           ei      pointer to interface hello should be sent
 731  * @param[in]           flags type of hello packet
 732  * @param[in]           nbr_addr  pointer to neighbor address for Peer Termination TLV
 733  *
 734  * @return void
 735  *
 736  * @par
 737  * Build and enqueue a generic (multicast) periodic hello packet for
 738  * sending.  If no packets are currently queues, the packet will be
 739  * sent immadiatly
 740  */
 741 void
 742 eigrp_hello_send (struct eigrp_interface *ei, u_char flags, struct in_addr *nbr_addr)
 743 {
 744   struct eigrp_packet *ep = NULL;
 745
 746   /* If this is passive interface, do not send EIGRP Hello.
 747      if ((EIGRP_IF_PASSIVE_STATUS (ei) == EIGRP_IF_PASSIVE) ||
 748      (ei->type != EIGRP_IFTYPE_NBMA))
 749      return;
 750   */
 751
 752   if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 753     zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 754
 755   /* if packet was succesfully created, then add it to the interface queue */
 756   ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags, nbr_addr);
 757
 758   if (ep)
 759     {
 760       // Add packet to the top of the interface output queue
 761       eigrp_fifo_push_head(ei->obuf, ep);
 762
 763       /* Hook thread to write packet. */
 764       if (ei->on_write_q == 0)
 765         {
 766           listnode_add(ei->eigrp->oi_write_q, ei);
 767           ei->on_write_q = 1;
 768         }
 769
 770       if (ei->eigrp->t_write == NULL)
 771         {
 772           if(flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 773             {
 774               thread_execute(master, eigrp_write, ei->eigrp, ei->eigrp->fd);
 775             }
 776           else
 777             {
 778               thread_add_write(master, eigrp_write, ei->eigrp, ei->eigrp->fd,
 779                                &ei->eigrp->t_write);
 780             }
 781         }
 782     }
 783 }