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 #include "eigrpd/eigrp_errors.h"
  58
  59 /* Packet Type String. */
  60 static const struct message eigrp_general_tlv_type_str[] = {
  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  * @fn eigrp_hello_timer
  74  *
  75  * @param[in]   thread  current execution thread timer is associated with
  76  *
  77  * @return int  always returns 0
  78  *
  79  * @par
  80  * Called once per "hello" time interval, default 5 seconds
  81  * Sends hello packet via multicast for all interfaces eigrp
  82  * is configured for
  83  */
  84 int eigrp_hello_timer(struct thread *thread)
  85 {
  86         struct eigrp_interface *ei;
  87
  88         ei = THREAD_ARG(thread);
  89
  90         if (IS_DEBUG_EIGRP(0, TIMERS))
  91                 zlog_debug("Start Hello Timer (%s) Expire [%u]", IF_NAME(ei),
  92                            ei->params.v_hello);
  93
  94         /* Sending hello packet. */
  95         eigrp_hello_send(ei, EIGRP_HELLO_NORMAL, NULL);
  96
  97         /* Hello timer set. */
  98         thread_add_timer(master, eigrp_hello_timer, ei, ei->params.v_hello,
  99                          &ei->t_hello);
 100
 101         return 0;
 102 }
 103
 104 /**
 105  * @fn eigrp_hello_parameter_decode
 106  *
 107  * @param[in]           nbr     neighbor the ACK should be sent to
 108  * @param[in]           param   pointer packet TLV is stored to
 109  *
 110  * @return uint16_t     number of bytes added to packet stream
 111  *
 112  * @par
 113  * Encode Parameter TLV, used to convey metric weights and the hold time.
 114  *
 115  * @usage
 116  * Note the addition of K6 for the new extended metrics, and does not apply to
 117  * older TLV packet formats.
 118  */
 119 static struct eigrp_neighbor *
 120 eigrp_hello_parameter_decode(struct eigrp_neighbor *nbr,
 121                              struct eigrp_tlv_hdr_type *tlv)
 122 {
 123         struct eigrp *eigrp = nbr->ei->eigrp;
 124         struct TLV_Parameter_Type *param = (struct TLV_Parameter_Type *)tlv;
 125
 126         /* First validate TLV length */
 127         if (tlv->length < sizeof(struct TLV_Parameter_Type))
 128                 return NULL;
 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) && (eigrp->k_values[1] == nbr->K2)
 144             && (eigrp->k_values[2] == nbr->K3)
 145             && (eigrp->k_values[3] == nbr->K4)
 146             && (eigrp->k_values[4] == nbr->K5)) {
 147
 148                 if (eigrp_nbr_state_get(nbr) == EIGRP_NEIGHBOR_DOWN) {
 149                         zlog_info(
 150                                 "Neighbor %pI4 (%s) is pending: new adjacency",
 151                                 &nbr->src,
 152                                 ifindex2ifname(nbr->ei->ifp->ifindex,
 153                                                eigrp->vrf_id));
 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) >
 159                         //     ntohl(nbr->src.s_addr))
 160                         eigrp_update_send_init(nbr);
 161
 162                         eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_PENDING);
 163                 }
 164         } else {
 165                 if (eigrp_nbr_state_get(nbr) != EIGRP_NEIGHBOR_DOWN) {
 166                         if ((param->K1 & param->K2 & param->K3 & param->K4
 167                              & param->K5)
 168                             == 255) {
 169                                 zlog_info(
 170                                         "Neighbor %pI4 (%s) is down: Interface PEER-TERMINATION received",
 171                                         &nbr->src,
 172                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 173                                                        eigrp->vrf_id));
 174                                 eigrp_nbr_delete(nbr);
 175                                 return NULL;
 176                         } else {
 177                                 zlog_info(
 178                                         "Neighbor %pI4 (%s) going down: Kvalue mismatch",
 179                                         &nbr->src,
 180                                         ifindex2ifname(nbr->ei->ifp->ifindex,
 181                                                        eigrp->vrf_id));
 182                                 eigrp_nbr_state_set(nbr, EIGRP_NEIGHBOR_DOWN);
 183                         }
 184                 }
 185         }
 186
 187         return nbr;
 188 }
 189
 190 static uint8_t
 191 eigrp_hello_authentication_decode(struct stream *s,
 192                                   struct eigrp_tlv_hdr_type *tlv_header,
 193                                   struct eigrp_neighbor *nbr)
 194 {
 195         struct TLV_MD5_Authentication_Type *md5;
 196
 197         md5 = (struct TLV_MD5_Authentication_Type *)tlv_header;
 198
 199         if (md5->auth_type == EIGRP_AUTH_TYPE_MD5) {
 200                 /* Validate tlv length */
 201                 if (md5->length < sizeof(struct TLV_MD5_Authentication_Type))
 202                         return 0;
 203
 204                 return eigrp_check_md5_digest(s, md5, nbr,
 205                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 206         } else if (md5->auth_type == EIGRP_AUTH_TYPE_SHA256) {
 207                 /* Validate tlv length */
 208                 if (md5->length < sizeof(struct TLV_SHA256_Authentication_Type))
 209                         return 0;
 210
 211                 return eigrp_check_sha256_digest(
 212                         s, (struct TLV_SHA256_Authentication_Type *)tlv_header,
 213                         nbr, EIGRP_AUTH_BASIC_HELLO_FLAG);
 214         }
 215
 216         return 0;
 217 }
 218
 219 /**
 220  * @fn eigrp_sw_version_decode
 221  *
 222  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 223  * @param[in]           param   pointer to TLV software version information
 224  *
 225  * @return void
 226  *
 227  * @par
 228  * Read the software version in the specified location.
 229  * This consists of two bytes of OS version, and two bytes of EIGRP
 230  * revision number.
 231  */
 232 static void eigrp_sw_version_decode(struct eigrp_neighbor *nbr,
 233                                     struct eigrp_tlv_hdr_type *tlv)
 234 {
 235         struct TLV_Software_Type *version = (struct TLV_Software_Type *)tlv;
 236
 237         /* Validate TLV length */
 238         if (tlv->length < sizeof(struct TLV_Software_Type))
 239                 return;
 240
 241         nbr->os_rel_major = version->vender_major;
 242         nbr->os_rel_minor = version->vender_minor;
 243         nbr->tlv_rel_major = version->eigrp_major;
 244         nbr->tlv_rel_minor = version->eigrp_minor;
 245         return;
 246 }
 247
 248 /**
 249  * @fn eigrp_peer_termination_decode
 250  *
 251  * @param[in]           nbr     neighbor the ACK shoudl be sent to
 252  * @param[in]           tlv     pointer to TLV software version information
 253  *
 254  * @return void
 255  *
 256  * @par
 257  * Read the address in the TLV and match to out address. If
 258  * a match is found, move the sending neighbor to the down state. If
 259  * out address is not in the TLV, then ignore the peer termination
 260  */
 261 static void eigrp_peer_termination_decode(struct eigrp_neighbor *nbr,
 262                                           struct eigrp_tlv_hdr_type *tlv)
 263 {
 264         struct eigrp *eigrp = nbr->ei->eigrp;
 265         struct TLV_Peer_Termination_type *param =
 266                 (struct TLV_Peer_Termination_type *)tlv;
 267
 268         /* Validate TLV length */
 269         if (tlv->length < sizeof(struct TLV_Peer_Termination_type))
 270                 return;
 271
 272         uint32_t my_ip = nbr->ei->address.u.prefix4.s_addr;
 273         uint32_t received_ip = param->neighbor_ip;
 274
 275         if (my_ip == received_ip) {
 276                 zlog_info(
 277                         "Neighbor %pI4 (%s) is down: Peer Termination received",
 278                         &nbr->src,
 279                         ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id));
 280                 /* set neighbor to DOWN */
 281                 nbr->state = EIGRP_NEIGHBOR_DOWN;
 282                 /* delete neighbor */
 283                 eigrp_nbr_delete(nbr);
 284         }
 285 }
 286
 287 /**
 288  * @fn eigrp_peer_termination_encode
 289  *
 290  * @param[in,out]   s             packet stream TLV is stored to
 291  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 292  * Termination TLV
 293  *
 294  * @return uint16_t    number of bytes added to packet stream
 295  *
 296  * @par
 297  * Function used to encode Peer Termination TLV to Hello packet.
 298  */
 299 static uint16_t eigrp_peer_termination_encode(struct stream *s,
 300                                               struct in_addr *nbr_addr)
 301 {
 302         uint16_t length = EIGRP_TLV_PEER_TERMINATION_LEN;
 303
 304         /* fill in type and length */
 305         stream_putw(s, EIGRP_TLV_PEER_TERMINATION);
 306         stream_putw(s, length);
 307
 308         /* fill in unknown field 0x04 */
 309         stream_putc(s, 0x04);
 310
 311         /* finally neighbor IP address */
 312         stream_put_ipv4(s, nbr_addr->s_addr);
 313
 314         return (length);
 315 }
 316
 317 /*
 318  * @fn eigrp_hello_receive
 319  *
 320  * @param[in]   eigrp           eigrp routing process
 321  * @param[in]   iph             pointer to ip header
 322  * @param[in]   eigrph          pointer to eigrp header
 323  * @param[in]   s               input ip stream
 324  * @param[in]   ei              eigrp interface packet arrived on
 325  * @param[in]   size            size of eigrp packet
 326  *
 327  * @return void
 328  *
 329  * @par
 330  * This is the main worker function for processing hello packets. It
 331  * will validate the peer associated with the src ip address of the ip
 332  * header, and then decode each of the general TLVs which the packet
 333  * may contain.
 334  *
 335  * @usage
 336  * Not all TLVs are current decoder.  This is a work in progress..
 337  */
 338 void eigrp_hello_receive(struct eigrp *eigrp, struct ip *iph,
 339                          struct eigrp_header *eigrph, struct stream *s,
 340                          struct eigrp_interface *ei, int size)
 341 {
 342         struct eigrp_tlv_hdr_type *tlv_header;
 343         struct eigrp_neighbor *nbr;
 344         uint16_t type;
 345         uint16_t length;
 346
 347         /* get neighbor struct */
 348         nbr = eigrp_nbr_get(ei, eigrph, iph);
 349
 350         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 351         assert(nbr);
 352
 353         if (IS_DEBUG_EIGRP_PACKET(eigrph->opcode - 1, RECV))
 354                 zlog_debug("Processing Hello size[%u] int(%s) nbr(%pI4)", size,
 355                            ifindex2ifname(nbr->ei->ifp->ifindex, eigrp->vrf_id),
 356                            &nbr->src);
 357
 358         size -= EIGRP_HEADER_LEN;
 359         if (size < 0)
 360                 return;
 361
 362         tlv_header = (struct eigrp_tlv_hdr_type *)eigrph->tlv;
 363
 364         do {
 365                 type = ntohs(tlv_header->type);
 366                 length = ntohs(tlv_header->length);
 367
 368                 /* Validate length against packet size */
 369                 if (length > size)
 370                         return;
 371
 372                 if ((length > 0) && (length <= size)) {
 373                         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 374                                 zlog_debug(
 375                                         "  General TLV(%s)",
 376                                         lookup_msg(eigrp_general_tlv_type_str,
 377                                                    type, NULL));
 378
 379                         // determine what General TLV is being processed
 380                         switch (type) {
 381                         case EIGRP_TLV_PARAMETER:
 382                                 nbr = eigrp_hello_parameter_decode(nbr,
 383                                                                    tlv_header);
 384                                 if (!nbr)
 385                                         return;
 386                                 break;
 387                         case EIGRP_TLV_AUTH: {
 388                                 if (eigrp_hello_authentication_decode(
 389                                             s, tlv_header, nbr)
 390                                     == 0)
 391                                         return;
 392                                 else
 393                                         break;
 394                                 break;
 395                         }
 396                         case EIGRP_TLV_SEQ:
 397                                 break;
 398                         case EIGRP_TLV_SW_VERSION:
 399                                 eigrp_sw_version_decode(nbr, tlv_header);
 400                                 break;
 401                         case EIGRP_TLV_NEXT_MCAST_SEQ:
 402                                 break;
 403                         case EIGRP_TLV_PEER_TERMINATION:
 404                                 eigrp_peer_termination_decode(nbr, tlv_header);
 405                                 return;
 406                                 break;
 407                         case EIGRP_TLV_PEER_MTRLIST:
 408                         case EIGRP_TLV_PEER_TIDLIST:
 409                                 break;
 410                         default:
 411                                 break;
 412                         }
 413                 }
 414
 415                 tlv_header = (struct eigrp_tlv_hdr_type *)(((char *)tlv_header)
 416                                                            + length);
 417                 size -= length;
 418
 419         } while (size > 0);
 420
 421
 422         /*If received packet is hello with Parameter TLV*/
 423         if (ntohl(eigrph->ack) == 0) {
 424                 /* increment statistics. */
 425                 ei->hello_in++;
 426                 if (nbr)
 427                         eigrp_nbr_state_update(nbr);
 428         }
 429
 430         if (IS_DEBUG_EIGRP_PACKET(0, RECV))
 431                 zlog_debug("Hello Packet received from %pI4", &nbr->src);
 432 }
 433
 434 uint32_t FRR_MAJOR;
 435 uint32_t FRR_MINOR;
 436
 437 void eigrp_sw_version_initialize(void)
 438 {
 439         char ver_string[] = VERSION;
 440         char *dash = strstr(ver_string, "-");
 441         int ret;
 442
 443         if (dash)
 444                 dash[0] = '\0';
 445
 446         ret = sscanf(ver_string, "%" SCNu32 ".%" SCNu32, &FRR_MAJOR,
 447                      &FRR_MINOR);
 448         if (ret != 2)
 449                 flog_err(EC_EIGRP_PACKET,
 450                          "Did not Properly parse %s, please fix VERSION string",
 451                          VERSION);
 452 }
 453
 454 /**
 455  * @fn eigrp_sw_version_encode
 456  *
 457  * @param[in,out]       s       packet stream TLV is stored to
 458  *
 459  * @return uint16_t     number of bytes added to packet stream
 460  *
 461  * @par
 462  * Store the software version in the specified location.
 463  * This consists of two bytes of OS version, and two bytes of EIGRP
 464  * revision number.
 465  */
 466 static uint16_t eigrp_sw_version_encode(struct stream *s)
 467 {
 468         uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 469
 470         // setup the tlv fields
 471         stream_putw(s, EIGRP_TLV_SW_VERSION);
 472         stream_putw(s, length);
 473
 474         stream_putc(s, FRR_MAJOR); //!< major os version
 475         stream_putc(s, FRR_MINOR); //!< minor os version
 476
 477         /* and the core eigrp version */
 478         stream_putc(s, EIGRP_MAJOR_VERSION);
 479         stream_putc(s, EIGRP_MINOR_VERSION);
 480
 481         return (length);
 482 }
 483
 484 /**
 485  * @fn eigrp_tidlist_encode
 486  *
 487  * @param[in,out]       s       packet stream TLV is stored to
 488  *
 489  * @return void
 490  *
 491  * @par
 492  * If doing mutli-topology, then store the supported TID list.
 493  * This is currently a place holder function
 494  */
 495 static uint16_t eigrp_tidlist_encode(struct stream *s)
 496 {
 497         // uint16_t length = EIGRP_TLV_SW_VERSION_LEN;
 498         return 0;
 499 }
 500
 501 /**
 502  * @fn eigrp_sequence_encode
 503  *
 504  * @param[in,out]       s       packet stream TLV is stored to
 505  *
 506  * @return uint16_t    number of bytes added to packet stream
 507  *
 508  * @par
 509  * Part of conditional receive process
 510  *
 511  */
 512 static uint16_t eigrp_sequence_encode(struct eigrp *eigrp, struct stream *s)
 513 {
 514         uint16_t length = EIGRP_TLV_SEQ_BASE_LEN;
 515         struct eigrp_interface *ei;
 516         struct listnode *node, *node2, *nnode2;
 517         struct eigrp_neighbor *nbr;
 518         size_t backup_end, size_end;
 519         int found;
 520
 521         // add in the parameters TLV
 522         backup_end = stream_get_endp(s);
 523         stream_putw(s, EIGRP_TLV_SEQ);
 524         size_end = s->endp;
 525         stream_putw(s, 0x0000);
 526         stream_putc(s, IPV4_MAX_BYTELEN);
 527
 528         found = 0;
 529         for (ALL_LIST_ELEMENTS_RO(eigrp->eiflist, node, ei)) {
 530                 for (ALL_LIST_ELEMENTS(ei->nbrs, node2, nnode2, nbr)) {
 531                         if (nbr->multicast_queue->count > 0) {
 532                                 length += (uint16_t)stream_put_ipv4(
 533                                         s, nbr->src.s_addr);
 534                                 found = 1;
 535                         }
 536                 }
 537         }
 538
 539         if (found == 0) {
 540                 stream_set_endp(s, backup_end);
 541                 return 0;
 542         }
 543
 544         backup_end = stream_get_endp(s);
 545         stream_set_endp(s, size_end);
 546         stream_putw(s, length);
 547         stream_set_endp(s, backup_end);
 548
 549         return length;
 550 }
 551
 552 /**
 553  * @fn eigrp_sequence_encode
 554  *
 555  * @param[in,out]       s       packet stream TLV is stored to
 556  *
 557  * @return uint16_t    number of bytes added to packet stream
 558  *
 559  * @par
 560  * Part of conditional receive process
 561  *
 562  */
 563 static uint16_t eigrp_next_sequence_encode(struct eigrp *eigrp,
 564                                            struct stream *s)
 565 {
 566         uint16_t length = EIGRP_NEXT_SEQUENCE_TLV_SIZE;
 567
 568         // add in the parameters TLV
 569         stream_putw(s, EIGRP_TLV_NEXT_MCAST_SEQ);
 570         stream_putw(s, EIGRP_NEXT_SEQUENCE_TLV_SIZE);
 571         stream_putl(s, eigrp->sequence_number + 1);
 572
 573         return length;
 574 }
 575
 576 /**
 577  * @fn eigrp_hello_parameter_encode
 578  *
 579  * @param[in]           ei      pointer to interface hello packet came in on
 580  * @param[in,out]       s       packet stream TLV is stored to
 581  *
 582  * @return uint16_t     number of bytes added to packet stream
 583  *
 584  * @par
 585  * Encode Parameter TLV, used to convey metric weights and the hold time.
 586  *
 587  * @usage
 588  * Note the addition of K6 for the new extended metrics, and does not apply to
 589  * older TLV packet formats.
 590  */
 591 static uint16_t eigrp_hello_parameter_encode(struct eigrp_interface *ei,
 592                                              struct stream *s, uint8_t flags)
 593 {
 594         // add in the parameters TLV
 595         stream_putw(s, EIGRP_TLV_PARAMETER);
 596         stream_putw(s, EIGRP_TLV_PARAMETER_LEN);
 597
 598         // if graceful shutdown is needed to be announced, send all 255 in K
 599         // values
 600         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 601                 stream_putc(s, 0xff); /* K1 */
 602                 stream_putc(s, 0xff); /* K2 */
 603                 stream_putc(s, 0xff); /* K3 */
 604                 stream_putc(s, 0xff); /* K4 */
 605                 stream_putc(s, 0xff); /* K5 */
 606                 stream_putc(s, 0xff); /* K6 */
 607         } else                        // set k values
 608         {
 609                 stream_putc(s, ei->eigrp->k_values[0]); /* K1 */
 610                 stream_putc(s, ei->eigrp->k_values[1]); /* K2 */
 611                 stream_putc(s, ei->eigrp->k_values[2]); /* K3 */
 612                 stream_putc(s, ei->eigrp->k_values[3]); /* K4 */
 613                 stream_putc(s, ei->eigrp->k_values[4]); /* K5 */
 614                 stream_putc(s, ei->eigrp->k_values[5]); /* K6 */
 615         }
 616
 617         // and set hold time value..
 618         stream_putw(s, ei->params.v_wait);
 619
 620         return EIGRP_TLV_PARAMETER_LEN;
 621 }
 622
 623 /**
 624  * @fn eigrp_hello_encode
 625  *
 626  * @param[in]           ei      pointer to interface hello packet came in on
 627  * @param[in]           s       packet stream TLV is stored to
 628  * @param[in]           ack      if non-zero, neigbors sequence packet to ack
 629  * @param[in]           flags  type of hello packet
 630  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 631  * Termination TLV
 632  *
 633  * @return eigrp_packet         pointer initialize hello packet
 634  *
 635  * @par
 636  * Allocate an EIGRP hello packet, and add in the the approperate TLVs
 637  *
 638  */
 639 static struct eigrp_packet *eigrp_hello_encode(struct eigrp_interface *ei,
 640                                                in_addr_t addr, uint32_t ack,
 641                                                uint8_t flags,
 642                                                struct in_addr *nbr_addr)
 643 {
 644         struct eigrp_packet *ep;
 645         uint16_t length = EIGRP_HEADER_LEN;
 646
 647         // allocate a new packet to be sent
 648         ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), NULL);
 649
 650         if (ep) {
 651                 // encode common header feilds
 652                 eigrp_packet_header_init(EIGRP_OPC_HELLO, ei->eigrp, ep->s, 0,
 653                                          0, ack);
 654
 655                 // encode Authentication TLV
 656                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 657                     && (ei->params.auth_keychain != NULL)) {
 658                         length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 659                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 660                            && (ei->params.auth_keychain != NULL)) {
 661                         length += eigrp_add_authTLV_SHA256_to_stream(ep->s, ei);
 662                 }
 663
 664                 /* encode appropriate parameters to Hello packet */
 665                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN)
 666                         length += eigrp_hello_parameter_encode(
 667                                 ei, ep->s, EIGRP_HELLO_GRACEFUL_SHUTDOWN);
 668                 else
 669                         length += eigrp_hello_parameter_encode(
 670                                 ei, ep->s, EIGRP_HELLO_NORMAL);
 671
 672                 // figure out the version of code we're running
 673                 length += eigrp_sw_version_encode(ep->s);
 674
 675                 if (flags & EIGRP_HELLO_ADD_SEQUENCE) {
 676                         length += eigrp_sequence_encode(ei->eigrp, ep->s);
 677                         length += eigrp_next_sequence_encode(ei->eigrp, ep->s);
 678                 }
 679
 680                 // add in the TID list if doing multi-topology
 681                 length += eigrp_tidlist_encode(ep->s);
 682
 683                 /* encode Peer Termination TLV if needed */
 684                 if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN_NBR)
 685                         length +=
 686                                 eigrp_peer_termination_encode(ep->s, nbr_addr);
 687
 688                 // Set packet length
 689                 ep->length = length;
 690
 691                 // set soruce address for the hello packet
 692                 ep->dst.s_addr = addr;
 693
 694                 if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 695                     && (ei->params.auth_keychain != NULL)) {
 696                         eigrp_make_md5_digest(ei, ep->s,
 697                                               EIGRP_AUTH_BASIC_HELLO_FLAG);
 698                 } else if ((ei->params.auth_type == EIGRP_AUTH_TYPE_SHA256)
 699                            && (ei->params.auth_keychain != NULL)) {
 700                         eigrp_make_sha256_digest(ei, ep->s,
 701                                                  EIGRP_AUTH_BASIC_HELLO_FLAG);
 702                 }
 703
 704                 // EIGRP Checksum
 705                 eigrp_packet_checksum(ei, ep->s, length);
 706         }
 707
 708         return (ep);
 709 }
 710
 711 /**
 712  * @fn eigrp_hello_send
 713  *
 714  * @param[in]           nbr     neighbor the ACK should be sent to
 715  *
 716  * @return void
 717  *
 718  * @par
 719  *  Send (unicast) a hello packet with the destination address
 720  *  associated with the neighbor.  The eigrp header ACK feild will be
 721  *  updated to the neighbor's sequence number to acknolodge any
 722  *  outstanding packets
 723  */
 724 void eigrp_hello_send_ack(struct eigrp_neighbor *nbr)
 725 {
 726         struct eigrp_packet *ep;
 727
 728         /* if packet succesfully created, add it to the interface queue */
 729         ep = eigrp_hello_encode(nbr->ei, nbr->src.s_addr,
 730                                 nbr->recv_sequence_number, EIGRP_HELLO_NORMAL,
 731                                 NULL);
 732
 733         if (ep) {
 734                 if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 735                         zlog_debug("Queueing [Hello] Ack Seq [%u] nbr [%pI4]",
 736                                    nbr->recv_sequence_number, &nbr->src);
 737
 738                 /* Add packet to the top of the interface output queue*/
 739                 eigrp_fifo_push(nbr->ei->obuf, ep);
 740
 741                 /* Hook thread to write packet. */
 742                 if (nbr->ei->on_write_q == 0) {
 743                         listnode_add(nbr->ei->eigrp->oi_write_q, nbr->ei);
 744                         nbr->ei->on_write_q = 1;
 745                 }
 746                 thread_add_write(master, eigrp_write, nbr->ei->eigrp,
 747                                  nbr->ei->eigrp->fd, &nbr->ei->eigrp->t_write);
 748         }
 749 }
 750
 751 /**
 752  * @fn eigrp_hello_send
 753  *
 754  * @param[in]           ei      pointer to interface hello should be sent
 755  * @param[in]           flags type of hello packet
 756  * @param[in]           nbr_addr  pointer to neighbor address for Peer
 757  * Termination TLV
 758  *
 759  * @return void
 760  *
 761  * @par
 762  * Build and enqueue a generic (multicast) periodic hello packet for
 763  * sending.  If no packets are currently queues, the packet will be
 764  * sent immadiatly
 765  */
 766 void eigrp_hello_send(struct eigrp_interface *ei, uint8_t flags,
 767                       struct in_addr *nbr_addr)
 768 {
 769         struct eigrp_packet *ep = NULL;
 770
 771         if (IS_DEBUG_EIGRP_PACKET(0, SEND))
 772                 zlog_debug("Queueing [Hello] Interface(%s)", IF_NAME(ei));
 773
 774         /* if packet was succesfully created, then add it to the interface queue
 775          */
 776         ep = eigrp_hello_encode(ei, htonl(EIGRP_MULTICAST_ADDRESS), 0, flags,
 777                                 nbr_addr);
 778
 779         if (ep) {
 780                 // Add packet to the top of the interface output queue
 781                 eigrp_fifo_push(ei->obuf, ep);
 782
 783                 /* Hook thread to write packet. */
 784                 if (ei->on_write_q == 0) {
 785                         listnode_add(ei->eigrp->oi_write_q, ei);
 786                         ei->on_write_q = 1;
 787                 }
 788
 789                 if (ei->eigrp->t_write == NULL) {
 790                         if (flags & EIGRP_HELLO_GRACEFUL_SHUTDOWN) {
 791                                 thread_execute(master, eigrp_write, ei->eigrp,
 792                                                ei->eigrp->fd);
 793                         } else {
 794                                 thread_add_write(master, eigrp_write, ei->eigrp,
 795                                                  ei->eigrp->fd,
 796                                                  &ei->eigrp->t_write);
 797                         }
 798                 }
 799         }
 800 }