pimd/pim_nht.c

   1 /*
   2  * PIM for Quagga
   3  * Copyright (C) 2017 Cumulus Networks, Inc.
   4  * Chirag Shah
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program 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 along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20 #include <zebra.h>
  21 #include "network.h"
  22 #include "zclient.h"
  23 #include "stream.h"
  24 #include "nexthop.h"
  25 #include "if.h"
  26 #include "hash.h"
  27 #include "jhash.h"
  28
  29 #include "lib/printfrr.h"
  30
  31 #include "pimd.h"
  32 #include "pimd/pim_nht.h"
  33 #include "log.h"
  34 #include "pim_time.h"
  35 #include "pim_oil.h"
  36 #include "pim_ifchannel.h"
  37 #include "pim_mroute.h"
  38 #include "pim_zebra.h"
  39 #include "pim_upstream.h"
  40 #include "pim_join.h"
  41 #include "pim_jp_agg.h"
  42 #include "pim_zebra.h"
  43 #include "pim_zlookup.h"
  44 #include "pim_rp.h"
  45
  46 /**
  47  * pim_sendmsg_zebra_rnh -- Format and send a nexthop register/Unregister
  48  *   command to Zebra.
  49  */
  50 void pim_sendmsg_zebra_rnh(struct pim_instance *pim, struct zclient *zclient,
  51                            struct pim_nexthop_cache *pnc, int command)
  52 {
  53         struct prefix *p;
  54         int ret;
  55
  56         p = &(pnc->rpf.rpf_addr);
  57         ret = zclient_send_rnh(zclient, command, p, false, false,
  58                                pim->vrf->vrf_id);
  59         if (ret == ZCLIENT_SEND_FAILURE)
  60                 zlog_warn("sendmsg_nexthop: zclient_send_message() failed");
  61
  62         if (PIM_DEBUG_PIM_NHT)
  63                 zlog_debug(
  64                         "%s: NHT %sregistered addr %pFX(%s) with Zebra ret:%d ",
  65                         __func__,
  66                         (command == ZEBRA_NEXTHOP_REGISTER) ? " " : "de", p,
  67                         pim->vrf->name, ret);
  68
  69         return;
  70 }
  71
  72 struct pim_nexthop_cache *pim_nexthop_cache_find(struct pim_instance *pim,
  73                                                  struct pim_rpf *rpf)
  74 {
  75         struct pim_nexthop_cache *pnc = NULL;
  76         struct pim_nexthop_cache lookup;
  77
  78         lookup.rpf.rpf_addr.family = rpf->rpf_addr.family;
  79         lookup.rpf.rpf_addr.prefixlen = rpf->rpf_addr.prefixlen;
  80         lookup.rpf.rpf_addr.u.prefix4.s_addr = rpf->rpf_addr.u.prefix4.s_addr;
  81
  82         pnc = hash_lookup(pim->rpf_hash, &lookup);
  83
  84         return pnc;
  85 }
  86
  87 static struct pim_nexthop_cache *pim_nexthop_cache_add(struct pim_instance *pim,
  88                                                        struct pim_rpf *rpf_addr)
  89 {
  90         struct pim_nexthop_cache *pnc;
  91         char hash_name[64];
  92
  93         pnc = XCALLOC(MTYPE_PIM_NEXTHOP_CACHE,
  94                       sizeof(struct pim_nexthop_cache));
  95         pnc->rpf.rpf_addr.family = rpf_addr->rpf_addr.family;
  96         pnc->rpf.rpf_addr.prefixlen = rpf_addr->rpf_addr.prefixlen;
  97         pnc->rpf.rpf_addr.u.prefix4.s_addr =
  98                 rpf_addr->rpf_addr.u.prefix4.s_addr;
  99
 100         pnc = hash_get(pim->rpf_hash, pnc, hash_alloc_intern);
 101
 102         pnc->rp_list = list_new();
 103         pnc->rp_list->cmp = pim_rp_list_cmp;
 104
 105         snprintfrr(hash_name, sizeof(hash_name), "PNC %pFX(%s) Upstream Hash",
 106                    &pnc->rpf.rpf_addr, pim->vrf->name);
 107         pnc->upstream_hash = hash_create_size(8192, pim_upstream_hash_key,
 108                                               pim_upstream_equal, hash_name);
 109
 110         return pnc;
 111 }
 112
 113 static struct pim_nexthop_cache *pim_nht_get(struct pim_instance *pim,
 114                                              struct prefix *addr)
 115 {
 116         struct pim_nexthop_cache *pnc = NULL;
 117         struct pim_rpf rpf;
 118         struct zclient *zclient = NULL;
 119
 120         zclient = pim_zebra_zclient_get();
 121         memset(&rpf, 0, sizeof(struct pim_rpf));
 122         rpf.rpf_addr.family = addr->family;
 123         rpf.rpf_addr.prefixlen = addr->prefixlen;
 124         rpf.rpf_addr.u.prefix4 = addr->u.prefix4;
 125
 126         pnc = pim_nexthop_cache_find(pim, &rpf);
 127         if (!pnc) {
 128                 pnc = pim_nexthop_cache_add(pim, &rpf);
 129                 pim_sendmsg_zebra_rnh(pim, zclient, pnc,
 130                                       ZEBRA_NEXTHOP_REGISTER);
 131                 if (PIM_DEBUG_PIM_NHT)
 132                         zlog_debug(
 133                                 "%s: NHT cache and zebra notification added for %pFX(%s)",
 134                                 __func__, addr, pim->vrf->name);
 135         }
 136
 137         return pnc;
 138 }
 139
 140 /* TBD: this does several distinct things and should probably be split up.
 141  * (checking state vs. returning pnc vs. adding upstream vs. adding rp)
 142  */
 143 int pim_find_or_track_nexthop(struct pim_instance *pim, struct prefix *addr,
 144                               struct pim_upstream *up, struct rp_info *rp,
 145                               struct pim_nexthop_cache *out_pnc)
 146 {
 147         struct pim_nexthop_cache *pnc;
 148         struct listnode *ch_node = NULL;
 149
 150         pnc = pim_nht_get(pim, addr);
 151
 152         assertf(up || rp, "addr=%pFX", addr);
 153
 154         if (rp != NULL) {
 155                 ch_node = listnode_lookup(pnc->rp_list, rp);
 156                 if (ch_node == NULL)
 157                         listnode_add_sort(pnc->rp_list, rp);
 158         }
 159
 160         if (up != NULL)
 161                 hash_get(pnc->upstream_hash, up, hash_alloc_intern);
 162
 163         if (CHECK_FLAG(pnc->flags, PIM_NEXTHOP_VALID)) {
 164                 if (out_pnc)
 165                         memcpy(out_pnc, pnc, sizeof(struct pim_nexthop_cache));
 166                 return 1;
 167         }
 168
 169         return 0;
 170 }
 171
 172 void pim_nht_bsr_add(struct pim_instance *pim, struct in_addr addr)
 173 {
 174         struct pim_nexthop_cache *pnc;
 175         struct prefix pfx;
 176
 177         pfx.family = AF_INET;
 178         pfx.prefixlen = IPV4_MAX_BITLEN;
 179         pfx.u.prefix4 = addr;
 180
 181         pnc = pim_nht_get(pim, &pfx);
 182
 183         pnc->bsr_count++;
 184 }
 185
 186 static void pim_nht_drop_maybe(struct pim_instance *pim,
 187                                struct pim_nexthop_cache *pnc)
 188 {
 189         if (PIM_DEBUG_PIM_NHT)
 190                 zlog_debug(
 191                         "%s: NHT %pFX(%s) rp_list count:%d upstream count:%ld BSR count:%u",
 192                         __func__, &pnc->rpf.rpf_addr, pim->vrf->name,
 193                         pnc->rp_list->count, pnc->upstream_hash->count,
 194                         pnc->bsr_count);
 195
 196         if (pnc->rp_list->count == 0 && pnc->upstream_hash->count == 0
 197             && pnc->bsr_count == 0) {
 198                 struct zclient *zclient = pim_zebra_zclient_get();
 199
 200                 pim_sendmsg_zebra_rnh(pim, zclient, pnc,
 201                                       ZEBRA_NEXTHOP_UNREGISTER);
 202
 203                 list_delete(&pnc->rp_list);
 204                 hash_free(pnc->upstream_hash);
 205
 206                 hash_release(pim->rpf_hash, pnc);
 207                 if (pnc->nexthop)
 208                         nexthops_free(pnc->nexthop);
 209                 XFREE(MTYPE_PIM_NEXTHOP_CACHE, pnc);
 210         }
 211 }
 212
 213 void pim_delete_tracked_nexthop(struct pim_instance *pim, struct prefix *addr,
 214                                 struct pim_upstream *up, struct rp_info *rp)
 215 {
 216         struct pim_nexthop_cache *pnc = NULL;
 217         struct pim_nexthop_cache lookup;
 218         struct pim_upstream *upstream = NULL;
 219
 220         /* Remove from RPF hash if it is the last entry */
 221         lookup.rpf.rpf_addr = *addr;
 222         pnc = hash_lookup(pim->rpf_hash, &lookup);
 223         if (!pnc) {
 224                 zlog_warn("attempting to delete nonexistent NHT entry %pFX",
 225                           addr);
 226                 return;
 227         }
 228
 229         if (rp) {
 230                 /* Release the (*, G)upstream from pnc->upstream_hash,
 231                  * whose Group belongs to the RP getting deleted
 232                  */
 233                 frr_each (rb_pim_upstream, &pim->upstream_head, upstream) {
 234                         struct prefix grp;
 235                         struct rp_info *trp_info;
 236
 237                         if (upstream->sg.src.s_addr != INADDR_ANY)
 238                                 continue;
 239
 240                         grp.family = AF_INET;
 241                         grp.prefixlen = IPV4_MAX_BITLEN;
 242                         grp.u.prefix4 = upstream->sg.grp;
 243
 244                         trp_info = pim_rp_find_match_group(pim, &grp);
 245                         if (trp_info == rp)
 246                                 hash_release(pnc->upstream_hash, upstream);
 247                 }
 248                 listnode_delete(pnc->rp_list, rp);
 249         }
 250
 251         if (up)
 252                 hash_release(pnc->upstream_hash, up);
 253
 254         pim_nht_drop_maybe(pim, pnc);
 255 }
 256
 257 void pim_nht_bsr_del(struct pim_instance *pim, struct in_addr addr)
 258 {
 259         struct pim_nexthop_cache *pnc = NULL;
 260         struct pim_nexthop_cache lookup;
 261
 262         lookup.rpf.rpf_addr.family = AF_INET;
 263         lookup.rpf.rpf_addr.prefixlen = IPV4_MAX_BITLEN;
 264         lookup.rpf.rpf_addr.u.prefix4 = addr;
 265
 266         pnc = hash_lookup(pim->rpf_hash, &lookup);
 267
 268         if (!pnc) {
 269                 zlog_warn("attempting to delete nonexistent NHT BSR entry %pI4",
 270                           &addr);
 271                 return;
 272         }
 273
 274         assertf(pnc->bsr_count > 0, "addr=%pI4", &addr);
 275         pnc->bsr_count--;
 276
 277         pim_nht_drop_maybe(pim, pnc);
 278 }
 279
 280 bool pim_nht_bsr_rpf_check(struct pim_instance *pim, struct in_addr bsr_addr,
 281                            struct interface *src_ifp, struct in_addr src_ip)
 282 {
 283         struct pim_nexthop_cache *pnc = NULL;
 284         struct pim_nexthop_cache lookup;
 285         struct pim_neighbor *nbr = NULL;
 286         struct nexthop *nh;
 287         struct interface *ifp;
 288
 289         lookup.rpf.rpf_addr.family = AF_INET;
 290         lookup.rpf.rpf_addr.prefixlen = IPV4_MAX_BITLEN;
 291         lookup.rpf.rpf_addr.u.prefix4 = bsr_addr;
 292
 293         pnc = hash_lookup(pim->rpf_hash, &lookup);
 294         if (!pnc || !CHECK_FLAG(pnc->flags, PIM_NEXTHOP_ANSWER_RECEIVED)) {
 295                 /* BSM from a new freshly registered BSR - do a synchronous
 296                  * zebra query since otherwise we'd drop the first packet,
 297                  * leading to additional delay in picking up BSM data
 298                  */
 299
 300                 /* FIXME: this should really be moved into a generic NHT
 301                  * function that does "add and get immediate result" or maybe
 302                  * "check cache or get immediate result." But until that can
 303                  * be worked in, here's a copy of the code below :(
 304                  */
 305                 struct pim_zlookup_nexthop nexthop_tab[MULTIPATH_NUM];
 306                 ifindex_t i;
 307                 struct interface *ifp = NULL;
 308                 int num_ifindex;
 309
 310                 memset(nexthop_tab, 0, sizeof(nexthop_tab));
 311                 num_ifindex = zclient_lookup_nexthop(pim, nexthop_tab,
 312                                                      MULTIPATH_NUM, bsr_addr,
 313                                                      PIM_NEXTHOP_LOOKUP_MAX);
 314
 315                 if (num_ifindex <= 0)
 316                         return false;
 317
 318                 for (i = 0; i < num_ifindex; i++) {
 319                         struct pim_zlookup_nexthop *znh = &nexthop_tab[i];
 320
 321                         /* pim_zlookup_nexthop has no ->type */
 322
 323                         /* 1:1 match code below with znh instead of nh */
 324                         ifp = if_lookup_by_index(znh->ifindex,
 325                                                  pim->vrf->vrf_id);
 326
 327                         if (!ifp || !ifp->info)
 328                                 continue;
 329
 330                         if (if_is_loopback(ifp) && if_is_loopback(src_ifp))
 331                                 return true;
 332
 333                         nbr = pim_neighbor_find(ifp,
 334                                                 znh->nexthop_addr.u.prefix4);
 335                         if (!nbr)
 336                                 continue;
 337
 338                         return znh->ifindex == src_ifp->ifindex
 339                                && znh->nexthop_addr.u.prefix4.s_addr
 340                                           == src_ip.s_addr;
 341                 }
 342                 return false;
 343         }
 344
 345         if (!CHECK_FLAG(pnc->flags, PIM_NEXTHOP_VALID))
 346                 return false;
 347
 348         /* if we accept BSMs from more than one ECMP nexthop, this will cause
 349          * BSM message "multiplication" for each ECMP hop.  i.e. if you have
 350          * 4-way ECMP and 4 hops you end up with 256 copies of each BSM
 351          * message.
 352          *
 353          * so...  only accept the first (IPv4) valid nexthop as source.
 354          */
 355
 356         for (nh = pnc->nexthop; nh; nh = nh->next) {
 357                 struct in_addr nhaddr;
 358
 359                 switch (nh->type) {
 360                 case NEXTHOP_TYPE_IPV4:
 361                         if (nh->ifindex == IFINDEX_INTERNAL)
 362                                 continue;
 363
 364                         /* fallthru */
 365                 case NEXTHOP_TYPE_IPV4_IFINDEX:
 366                         nhaddr = nh->gate.ipv4;
 367                         break;
 368
 369                 case NEXTHOP_TYPE_IFINDEX:
 370                         nhaddr = bsr_addr;
 371                         break;
 372
 373                 default:
 374                         continue;
 375                 }
 376
 377                 ifp = if_lookup_by_index(nh->ifindex, pim->vrf->vrf_id);
 378                 if (!ifp || !ifp->info)
 379                         continue;
 380
 381                 if (if_is_loopback(ifp) && if_is_loopback(src_ifp))
 382                         return true;
 383
 384                 /* MRIB (IGP) may be pointing at a router where PIM is down */
 385                 nbr = pim_neighbor_find(ifp, nhaddr);
 386                 if (!nbr)
 387                         continue;
 388
 389                 return nh->ifindex == src_ifp->ifindex
 390                        && nhaddr.s_addr == src_ip.s_addr;
 391         }
 392         return false;
 393 }
 394
 395 void pim_rp_nexthop_del(struct rp_info *rp_info)
 396 {
 397         rp_info->rp.source_nexthop.interface = NULL;
 398         rp_info->rp.source_nexthop.mrib_nexthop_addr.u.prefix4.s_addr =
 399                 PIM_NET_INADDR_ANY;
 400         rp_info->rp.source_nexthop.mrib_metric_preference =
 401                 router->infinite_assert_metric.metric_preference;
 402         rp_info->rp.source_nexthop.mrib_route_metric =
 403                 router->infinite_assert_metric.route_metric;
 404 }
 405
 406 /* Update RP nexthop info based on Nexthop update received from Zebra.*/
 407 static void pim_update_rp_nh(struct pim_instance *pim,
 408                              struct pim_nexthop_cache *pnc)
 409 {
 410         struct listnode *node = NULL;
 411         struct rp_info *rp_info = NULL;
 412
 413         /*Traverse RP list and update each RP Nexthop info */
 414         for (ALL_LIST_ELEMENTS_RO(pnc->rp_list, node, rp_info)) {
 415                 if (rp_info->rp.rpf_addr.u.prefix4.s_addr == INADDR_NONE)
 416                         continue;
 417
 418                 // Compute PIM RPF using cached nexthop
 419                 if (!pim_ecmp_nexthop_lookup(pim, &rp_info->rp.source_nexthop,
 420                                              &rp_info->rp.rpf_addr,
 421                                              &rp_info->group, 1))
 422                         pim_rp_nexthop_del(rp_info);
 423         }
 424 }
 425
 426 /* Update Upstream nexthop info based on Nexthop update received from Zebra.*/
 427 static int pim_update_upstream_nh_helper(struct hash_bucket *bucket, void *arg)
 428 {
 429         struct pim_instance *pim = (struct pim_instance *)arg;
 430         struct pim_upstream *up = (struct pim_upstream *)bucket->data;
 431
 432         enum pim_rpf_result rpf_result;
 433         struct pim_rpf old;
 434
 435         old.source_nexthop.interface = up->rpf.source_nexthop.interface;
 436         rpf_result = pim_rpf_update(pim, up, &old, __func__);
 437
 438         /* update kernel multicast forwarding cache (MFC); if the
 439          * RPF nbr is now unreachable the MFC has already been updated
 440          * by pim_rpf_clear
 441          */
 442         if (rpf_result != PIM_RPF_FAILURE)
 443                 pim_upstream_mroute_iif_update(up->channel_oil, __func__);
 444
 445         if (rpf_result == PIM_RPF_CHANGED ||
 446                 (rpf_result == PIM_RPF_FAILURE && old.source_nexthop.interface))
 447                 pim_zebra_upstream_rpf_changed(pim, up, &old);
 448
 449
 450         if (PIM_DEBUG_PIM_NHT) {
 451                 zlog_debug(
 452                         "%s: NHT upstream %s(%s) old ifp %s new ifp %s",
 453                         __func__, up->sg_str, pim->vrf->name,
 454                         old.source_nexthop.interface ? old.source_nexthop
 455                                                                .interface->name
 456                                                      : "Unknown",
 457                         up->rpf.source_nexthop.interface ? up->rpf.source_nexthop
 458                                                                    .interface->name
 459                                                          : "Unknown");
 460         }
 461
 462         return HASHWALK_CONTINUE;
 463 }
 464
 465 static int pim_update_upstream_nh(struct pim_instance *pim,
 466                                   struct pim_nexthop_cache *pnc)
 467 {
 468         hash_walk(pnc->upstream_hash, pim_update_upstream_nh_helper, pim);
 469
 470         pim_zebra_update_all_interfaces(pim);
 471
 472         return 0;
 473 }
 474
 475 uint32_t pim_compute_ecmp_hash(struct prefix *src, struct prefix *grp)
 476 {
 477         uint32_t hash_val;
 478         uint32_t s = 0, g = 0;
 479
 480         if ((!src))
 481                 return 0;
 482
 483         switch (src->family) {
 484         case AF_INET: {
 485                 s = src->u.prefix4.s_addr;
 486                 s = s == 0 ? 1 : s;
 487                 if (grp)
 488                         g = grp->u.prefix4.s_addr;
 489         } break;
 490         default:
 491                 break;
 492         }
 493
 494         hash_val = jhash_2words(g, s, 101);
 495         return hash_val;
 496 }
 497
 498 static int pim_ecmp_nexthop_search(struct pim_instance *pim,
 499                                    struct pim_nexthop_cache *pnc,
 500                                    struct pim_nexthop *nexthop,
 501                                    struct prefix *src, struct prefix *grp,
 502                                    int neighbor_needed)
 503 {
 504         struct pim_neighbor *nbrs[MULTIPATH_NUM], *nbr = NULL;
 505         struct interface *ifps[MULTIPATH_NUM];
 506         struct nexthop *nh_node = NULL;
 507         ifindex_t first_ifindex;
 508         struct interface *ifp = NULL;
 509         uint32_t hash_val = 0, mod_val = 0;
 510         uint8_t nh_iter = 0, found = 0;
 511         uint32_t i, num_nbrs = 0;
 512
 513         if (!pnc || !pnc->nexthop_num || !nexthop)
 514                 return 0;
 515
 516         memset(&nbrs, 0, sizeof(nbrs));
 517         memset(&ifps, 0, sizeof(ifps));
 518
 519         // Current Nexthop is VALID, check to stay on the current path.
 520         if (nexthop->interface && nexthop->interface->info
 521             && nexthop->mrib_nexthop_addr.u.prefix4.s_addr
 522                        != PIM_NET_INADDR_ANY) {
 523                 /* User configured knob to explicitly switch
 524                    to new path is disabled or current path
 525                    metric is less than nexthop update.
 526                  */
 527
 528                 if (pim->ecmp_rebalance_enable == 0) {
 529                         uint8_t curr_route_valid = 0;
 530                         // Check if current nexthop is present in new updated
 531                         // Nexthop list.
 532                         // If the current nexthop is not valid, candidate to
 533                         // choose new Nexthop.
 534                         for (nh_node = pnc->nexthop; nh_node;
 535                              nh_node = nh_node->next) {
 536                                 curr_route_valid = (nexthop->interface->ifindex
 537                                                     == nh_node->ifindex);
 538                                 if (curr_route_valid)
 539                                         break;
 540                         }
 541
 542                         if (curr_route_valid
 543                             && !pim_if_connected_to_source(nexthop->interface,
 544                                                            src->u.prefix4)) {
 545                                 nbr = pim_neighbor_find(
 546                                         nexthop->interface,
 547                                         nexthop->mrib_nexthop_addr.u.prefix4);
 548                                 if (!nbr
 549                                     && !if_is_loopback(nexthop->interface)) {
 550                                         if (PIM_DEBUG_PIM_NHT)
 551                                                 zlog_debug(
 552                                                         "%s: current nexthop does not have nbr ",
 553                                                         __func__);
 554                                 } else {
 555                                         /* update metric even if the upstream
 556                                          * neighbor stays unchanged
 557                                          */
 558                                         nexthop->mrib_metric_preference =
 559                                                 pnc->distance;
 560                                         nexthop->mrib_route_metric =
 561                                                 pnc->metric;
 562                                         if (PIM_DEBUG_PIM_NHT) {
 563                                                 char src_str[INET_ADDRSTRLEN];
 564                                                 pim_inet4_dump("<addr?>",
 565                                                                src->u.prefix4,
 566                                                                src_str,
 567                                                                sizeof(src_str));
 568                                                 char grp_str[INET_ADDRSTRLEN];
 569                                                 pim_inet4_dump("<addr?>",
 570                                                                grp->u.prefix4,
 571                                                                grp_str,
 572                                                                sizeof(grp_str));
 573                                                 zlog_debug(
 574                                                         "%s: (%s,%s)(%s) current nexthop %s is valid, skipping new path selection",
 575                                                         __func__, src_str,
 576                                                         grp_str, pim->vrf->name,
 577                                                         nexthop->interface->name);
 578                                         }
 579                                         return 1;
 580                                 }
 581                         }
 582                 }
 583         }
 584
 585         /*
 586          * Look up all interfaces and neighbors,
 587          * store for later usage
 588          */
 589         for (nh_node = pnc->nexthop, i = 0; nh_node;
 590              nh_node = nh_node->next, i++) {
 591                 ifps[i] =
 592                         if_lookup_by_index(nh_node->ifindex, pim->vrf->vrf_id);
 593                 if (ifps[i]) {
 594                         nbrs[i] = pim_neighbor_find(ifps[i],
 595                                                     nh_node->gate.ipv4);
 596                         if (nbrs[i] || pim_if_connected_to_source(ifps[i],
 597
 598                                                                   src->u.prefix4))
 599                                 num_nbrs++;
 600                 }
 601         }
 602         if (pim->ecmp_enable) {
 603                 uint32_t consider = pnc->nexthop_num;
 604
 605                 if (neighbor_needed && num_nbrs < consider)
 606                         consider = num_nbrs;
 607
 608                 if (consider == 0)
 609                         return 0;
 610
 611                 // PIM ECMP flag is enable then choose ECMP path.
 612                 hash_val = pim_compute_ecmp_hash(src, grp);
 613                 mod_val = hash_val % consider;
 614         }
 615
 616         for (nh_node = pnc->nexthop; nh_node && (found == 0);
 617              nh_node = nh_node->next) {
 618                 first_ifindex = nh_node->ifindex;
 619                 ifp = ifps[nh_iter];
 620                 if (!ifp) {
 621                         if (PIM_DEBUG_PIM_NHT) {
 622                                 char addr_str[INET_ADDRSTRLEN];
 623                                 pim_inet4_dump("<addr?>", src->u.prefix4,
 624                                                addr_str, sizeof(addr_str));
 625                                 zlog_debug(
 626                                         "%s %s: could not find interface for ifindex %d (address %s(%s))",
 627                                         __FILE__, __func__, first_ifindex,
 628                                         addr_str, pim->vrf->name);
 629                         }
 630                         if (nh_iter == mod_val)
 631                                 mod_val++; // Select nexthpath
 632                         nh_iter++;
 633                         continue;
 634                 }
 635                 if (!ifp->info) {
 636                         if (PIM_DEBUG_PIM_NHT) {
 637                                 char addr_str[INET_ADDRSTRLEN];
 638                                 pim_inet4_dump("<addr?>", src->u.prefix4,
 639                                                addr_str, sizeof(addr_str));
 640                                 zlog_debug(
 641                                         "%s: multicast not enabled on input interface %s(%s) (ifindex=%d, RPF for source %s)",
 642                                         __func__, ifp->name, pim->vrf->name,
 643                                         first_ifindex, addr_str);
 644                         }
 645                         if (nh_iter == mod_val)
 646                                 mod_val++; // Select nexthpath
 647                         nh_iter++;
 648                         continue;
 649                 }
 650
 651                 if (neighbor_needed
 652                     && !pim_if_connected_to_source(ifp, src->u.prefix4)) {
 653                         nbr = nbrs[nh_iter];
 654                         if (!nbr && !if_is_loopback(ifp)) {
 655                                 if (PIM_DEBUG_PIM_NHT)
 656                                         zlog_debug(
 657                                                 "%s: pim nbr not found on input interface %s(%s)",
 658                                                 __func__, ifp->name,
 659                                                 pim->vrf->name);
 660                                 if (nh_iter == mod_val)
 661                                         mod_val++; // Select nexthpath
 662                                 nh_iter++;
 663                                 continue;
 664                         }
 665                 }
 666
 667                 if (nh_iter == mod_val) {
 668                         nexthop->interface = ifp;
 669                         nexthop->mrib_nexthop_addr.family = AF_INET;
 670                         nexthop->mrib_nexthop_addr.prefixlen = IPV4_MAX_BITLEN;
 671                         nexthop->mrib_nexthop_addr.u.prefix4 =
 672                                 nh_node->gate.ipv4;
 673                         nexthop->mrib_metric_preference = pnc->distance;
 674                         nexthop->mrib_route_metric = pnc->metric;
 675                         nexthop->last_lookup = src->u.prefix4;
 676                         nexthop->last_lookup_time = pim_time_monotonic_usec();
 677                         nexthop->nbr = nbr;
 678                         found = 1;
 679                         if (PIM_DEBUG_PIM_NHT) {
 680                                 char buf[INET_ADDRSTRLEN];
 681                                 char buf2[INET_ADDRSTRLEN];
 682                                 char buf3[INET_ADDRSTRLEN];
 683                                 pim_inet4_dump("<src?>", src->u.prefix4, buf2,
 684                                                sizeof(buf2));
 685                                 pim_inet4_dump("<grp?>", grp->u.prefix4, buf3,
 686                                                sizeof(buf3));
 687                                 pim_inet4_dump(
 688                                         "<rpf?>",
 689                                         nexthop->mrib_nexthop_addr.u.prefix4,
 690                                         buf, sizeof(buf));
 691                                 zlog_debug(
 692                                         "%s: (%s,%s)(%s) selected nhop interface %s addr %s mod_val %u iter %d ecmp %d",
 693                                         __func__, buf2, buf3, pim->vrf->name,
 694                                         ifp->name, buf, mod_val, nh_iter,
 695                                         pim->ecmp_enable);
 696                         }
 697                 }
 698                 nh_iter++;
 699         }
 700
 701         if (found)
 702                 return 1;
 703         else
 704                 return 0;
 705 }
 706
 707 /* This API is used to parse Registered address nexthop update coming from Zebra
 708  */
 709 int pim_parse_nexthop_update(ZAPI_CALLBACK_ARGS)
 710 {
 711         struct nexthop *nexthop;
 712         struct nexthop *nhlist_head = NULL;
 713         struct nexthop *nhlist_tail = NULL;
 714         int i;
 715         struct pim_rpf rpf;
 716         struct pim_nexthop_cache *pnc = NULL;
 717         struct pim_neighbor *nbr = NULL;
 718         struct interface *ifp = NULL;
 719         struct interface *ifp1 = NULL;
 720         struct vrf *vrf = vrf_lookup_by_id(vrf_id);
 721         struct pim_instance *pim;
 722         struct zapi_route nhr;
 723
 724         if (!vrf)
 725                 return 0;
 726         pim = vrf->info;
 727
 728         if (!zapi_nexthop_update_decode(zclient->ibuf, &nhr)) {
 729                 zlog_err("%s: Decode of nexthop update from zebra failed",
 730                          __func__);
 731                 return 0;
 732         }
 733
 734         if (cmd == ZEBRA_NEXTHOP_UPDATE) {
 735                 prefix_copy(&rpf.rpf_addr, &nhr.prefix);
 736                 pnc = pim_nexthop_cache_find(pim, &rpf);
 737                 if (!pnc) {
 738                         if (PIM_DEBUG_PIM_NHT)
 739                                 zlog_debug(
 740                                         "%s: Skipping NHT update, addr %pFX is not in local cached DB.",
 741                                         __func__, &rpf.rpf_addr);
 742                         return 0;
 743                 }
 744         } else {
 745                 /*
 746                  * We do not currently handle ZEBRA_IMPORT_CHECK_UPDATE
 747                  */
 748                 return 0;
 749         }
 750
 751         pnc->last_update = pim_time_monotonic_usec();
 752
 753         if (nhr.nexthop_num) {
 754                 pnc->nexthop_num = 0; // Only increment for pim enabled rpf.
 755
 756                 for (i = 0; i < nhr.nexthop_num; i++) {
 757                         nexthop = nexthop_from_zapi_nexthop(&nhr.nexthops[i]);
 758                         switch (nexthop->type) {
 759                         case NEXTHOP_TYPE_IPV4:
 760                         case NEXTHOP_TYPE_IPV4_IFINDEX:
 761                         case NEXTHOP_TYPE_IPV6:
 762                         case NEXTHOP_TYPE_BLACKHOLE:
 763                                 break;
 764                         case NEXTHOP_TYPE_IFINDEX:
 765                                 /*
 766                                  * Connected route (i.e. no nexthop), use
 767                                  * RPF address from nexthop cache (i.e.
 768                                  * destination) as PIM nexthop.
 769                                  */
 770                                 nexthop->type = NEXTHOP_TYPE_IPV4_IFINDEX;
 771                                 nexthop->gate.ipv4 =
 772                                         pnc->rpf.rpf_addr.u.prefix4;
 773                                 break;
 774                         case NEXTHOP_TYPE_IPV6_IFINDEX:
 775                                 ifp1 = if_lookup_by_index(nexthop->ifindex,
 776                                                           pim->vrf->vrf_id);
 777
 778                                 if (!ifp1)
 779                                         nbr = NULL;
 780                                 else
 781                                         nbr = pim_neighbor_find_if(ifp1);
 782                                 /* Overwrite with Nbr address as NH addr */
 783                                 if (nbr)
 784                                         nexthop->gate.ipv4 = nbr->source_addr;
 785                                 else {
 786                                         // Mark nexthop address to 0 until PIM
 787                                         // Nbr is resolved.
 788                                         nexthop->gate.ipv4.s_addr =
 789                                                 PIM_NET_INADDR_ANY;
 790                                 }
 791
 792                                 break;
 793                         }
 794
 795                         ifp = if_lookup_by_index(nexthop->ifindex,
 796                                                  pim->vrf->vrf_id);
 797                         if (!ifp) {
 798                                 if (PIM_DEBUG_PIM_NHT) {
 799                                         char buf[NEXTHOP_STRLEN];
 800                                         zlog_debug(
 801                                                 "%s: could not find interface for ifindex %d(%s) (addr %s)",
 802                                                 __func__, nexthop->ifindex,
 803                                                 pim->vrf->name,
 804                                                 nexthop2str(nexthop, buf,
 805                                                             sizeof(buf)));
 806                                 }
 807                                 nexthop_free(nexthop);
 808                                 continue;
 809                         }
 810
 811                         if (PIM_DEBUG_PIM_NHT)
 812                                 zlog_debug(
 813                                         "%s: NHT addr %pFX(%s) %d-nhop via %pI4(%s) type %d distance:%u metric:%u ",
 814                                         __func__, &nhr.prefix, pim->vrf->name,
 815                                         i + 1, &nexthop->gate.ipv4,
 816                                         ifp->name, nexthop->type, nhr.distance,
 817                                         nhr.metric);
 818
 819                         if (!ifp->info) {
 820                                 /*
 821                                  * Though Multicast is not enabled on this
 822                                  * Interface store it in database otheriwse we
 823                                  * may miss this update and this will not cause
 824                                  * any issue, because while choosing the path we
 825                                  * are ommitting the Interfaces which are not
 826                                  * multicast enabled
 827                                  */
 828                                 if (PIM_DEBUG_PIM_NHT) {
 829                                         char buf[NEXTHOP_STRLEN];
 830
 831                                         zlog_debug(
 832                                                 "%s: multicast not enabled on input interface %s(%s) (ifindex=%d, addr %s)",
 833                                                 __func__, ifp->name,
 834                                                 pim->vrf->name,
 835                                                 nexthop->ifindex,
 836                                                 nexthop2str(nexthop, buf,
 837                                                             sizeof(buf)));
 838                                 }
 839                         }
 840
 841                         if (nhlist_tail) {
 842                                 nhlist_tail->next = nexthop;
 843                                 nhlist_tail = nexthop;
 844                         } else {
 845                                 nhlist_tail = nexthop;
 846                                 nhlist_head = nexthop;
 847                         }
 848                         // Only keep track of nexthops which are PIM enabled.
 849                         pnc->nexthop_num++;
 850                 }
 851                 /* Reset existing pnc->nexthop before assigning new list */
 852                 nexthops_free(pnc->nexthop);
 853                 pnc->nexthop = nhlist_head;
 854                 if (pnc->nexthop_num) {
 855                         pnc->flags |= PIM_NEXTHOP_VALID;
 856                         pnc->distance = nhr.distance;
 857                         pnc->metric = nhr.metric;
 858                 }
 859         } else {
 860                 pnc->flags &= ~PIM_NEXTHOP_VALID;
 861                 pnc->nexthop_num = nhr.nexthop_num;
 862                 nexthops_free(pnc->nexthop);
 863                 pnc->nexthop = NULL;
 864         }
 865         SET_FLAG(pnc->flags, PIM_NEXTHOP_ANSWER_RECEIVED);
 866
 867         if (PIM_DEBUG_PIM_NHT)
 868                 zlog_debug(
 869                         "%s: NHT Update for %pFX(%s) num_nh %d num_pim_nh %d vrf:%u up %ld rp %d",
 870                         __func__, &nhr.prefix, pim->vrf->name, nhr.nexthop_num,
 871                         pnc->nexthop_num, vrf_id, pnc->upstream_hash->count,
 872                         listcount(pnc->rp_list));
 873
 874         pim_rpf_set_refresh_time(pim);
 875
 876         if (listcount(pnc->rp_list))
 877                 pim_update_rp_nh(pim, pnc);
 878         if (pnc->upstream_hash->count)
 879                 pim_update_upstream_nh(pim, pnc);
 880
 881         return 0;
 882 }
 883
 884 int pim_ecmp_nexthop_lookup(struct pim_instance *pim,
 885                             struct pim_nexthop *nexthop, struct prefix *src,
 886                             struct prefix *grp, int neighbor_needed)
 887 {
 888         struct pim_nexthop_cache *pnc;
 889         struct pim_zlookup_nexthop nexthop_tab[MULTIPATH_NUM];
 890         struct pim_neighbor *nbrs[MULTIPATH_NUM], *nbr = NULL;
 891         struct pim_rpf rpf;
 892         int num_ifindex;
 893         struct interface *ifps[MULTIPATH_NUM], *ifp;
 894         int first_ifindex;
 895         int found = 0;
 896         uint8_t i = 0;
 897         uint32_t hash_val = 0, mod_val = 0;
 898         uint32_t num_nbrs = 0;
 899         char addr_str[PREFIX_STRLEN];
 900
 901         if (PIM_DEBUG_PIM_NHT) {
 902                 pim_inet4_dump("<addr?>", src->u.prefix4, addr_str,
 903                                sizeof(addr_str));
 904                 zlog_debug("%s: Looking up: %s(%s), last lookup time: %lld",
 905                            __func__, addr_str, pim->vrf->name,
 906                            nexthop->last_lookup_time);
 907         }
 908
 909         memset(&rpf, 0, sizeof(struct pim_rpf));
 910         rpf.rpf_addr.family = AF_INET;
 911         rpf.rpf_addr.prefixlen = IPV4_MAX_BITLEN;
 912         rpf.rpf_addr.u.prefix4 = src->u.prefix4;
 913
 914         pnc = pim_nexthop_cache_find(pim, &rpf);
 915         if (pnc) {
 916                 if (CHECK_FLAG(pnc->flags, PIM_NEXTHOP_ANSWER_RECEIVED))
 917                     return pim_ecmp_nexthop_search(pim, pnc, nexthop, src, grp,
 918                                                    neighbor_needed);
 919         }
 920
 921         memset(nexthop_tab, 0,
 922                sizeof(struct pim_zlookup_nexthop) * MULTIPATH_NUM);
 923         num_ifindex =
 924                 zclient_lookup_nexthop(pim, nexthop_tab, MULTIPATH_NUM,
 925                                        src->u.prefix4, PIM_NEXTHOP_LOOKUP_MAX);
 926         if (num_ifindex < 1) {
 927                 if (PIM_DEBUG_PIM_NHT)
 928                         zlog_warn(
 929                                 "%s: could not find nexthop ifindex for address %s(%s)",
 930                                 __func__, addr_str, pim->vrf->name);
 931                 return 0;
 932         }
 933
 934         memset(&nbrs, 0, sizeof(nbrs));
 935         memset(&ifps, 0, sizeof(ifps));
 936
 937         /*
 938          * Look up all interfaces and neighbors,
 939          * store for later usage
 940          */
 941         for (i = 0; i < num_ifindex; i++) {
 942                 ifps[i] = if_lookup_by_index(nexthop_tab[i].ifindex,
 943                                              pim->vrf->vrf_id);
 944                 if (ifps[i]) {
 945                         nbrs[i] = pim_neighbor_find(
 946                                 ifps[i], nexthop_tab[i].nexthop_addr.u.prefix4);
 947                         if (nbrs[i]
 948                             || pim_if_connected_to_source(ifps[i],
 949                                                           src->u.prefix4))
 950                                 num_nbrs++;
 951                 }
 952         }
 953
 954         // If PIM ECMP enable then choose ECMP path.
 955         if (pim->ecmp_enable) {
 956                 uint32_t consider = num_ifindex;
 957
 958                 if (neighbor_needed && num_nbrs < consider)
 959                         consider = num_nbrs;
 960
 961                 if (consider == 0)
 962                         return 0;
 963
 964                 hash_val = pim_compute_ecmp_hash(src, grp);
 965                 mod_val = hash_val % consider;
 966                 if (PIM_DEBUG_PIM_NHT_DETAIL)
 967                         zlog_debug("%s: hash_val %u mod_val %u", __func__,
 968                                    hash_val, mod_val);
 969         }
 970
 971         i = 0;
 972         while (!found && (i < num_ifindex)) {
 973                 first_ifindex = nexthop_tab[i].ifindex;
 974
 975                 ifp = ifps[i];
 976                 if (!ifp) {
 977                         if (PIM_DEBUG_PIM_NHT)
 978                                 zlog_debug(
 979                                         "%s %s: could not find interface for ifindex %d (address %s(%s))",
 980                                         __FILE__, __func__, first_ifindex,
 981                                         addr_str, pim->vrf->name);
 982                         if (i == mod_val)
 983                                 mod_val++;
 984                         i++;
 985                         continue;
 986                 }
 987
 988                 if (!ifp->info) {
 989                         if (PIM_DEBUG_PIM_NHT)
 990                                 zlog_debug(
 991                                         "%s: multicast not enabled on input interface %s(%s) (ifindex=%d, RPF for source %s)",
 992                                         __func__, ifp->name, pim->vrf->name,
 993                                         first_ifindex, addr_str);
 994                         if (i == mod_val)
 995                                 mod_val++;
 996                         i++;
 997                         continue;
 998                 }
 999                 if (neighbor_needed
1000                     && !pim_if_connected_to_source(ifp, src->u.prefix4)) {
1001                         nbr = nbrs[i];
1002                         if (PIM_DEBUG_PIM_NHT_DETAIL)
1003                                 zlog_debug("ifp name: %s(%s), pim nbr: %p",
1004                                            ifp->name, pim->vrf->name, nbr);
1005                         if (!nbr && !if_is_loopback(ifp)) {
1006                                 if (i == mod_val)
1007                                         mod_val++;
1008                                 i++;
1009                                 if (PIM_DEBUG_PIM_NHT)
1010                                         zlog_debug(
1011                                                 "%s: NBR not found on input interface %s(%s) (RPF for source %s)",
1012                                                 __func__, ifp->name,
1013                                                 pim->vrf->name, addr_str);
1014                                 continue;
1015                         }
1016                 }
1017
1018                 if (i == mod_val) {
1019                         if (PIM_DEBUG_PIM_NHT) {
1020                                 char nexthop_str[PREFIX_STRLEN];
1021
1022                                 pim_addr_dump("<nexthop?>",
1023                                               &nexthop_tab[i].nexthop_addr,
1024                                               nexthop_str, sizeof(nexthop_str));
1025                                 zlog_debug(
1026                                         "%s: found nhop %s for addr %s interface %s(%s) metric %d dist %d",
1027                                         __func__, nexthop_str, addr_str,
1028                                         ifp->name, pim->vrf->name,
1029                                         nexthop_tab[i].route_metric,
1030                                         nexthop_tab[i].protocol_distance);
1031                         }
1032                         /* update nexthop data */
1033                         nexthop->interface = ifp;
1034                         nexthop->mrib_nexthop_addr =
1035                                 nexthop_tab[i].nexthop_addr;
1036                         nexthop->mrib_metric_preference =
1037                                 nexthop_tab[i].protocol_distance;
1038                         nexthop->mrib_route_metric =
1039                                 nexthop_tab[i].route_metric;
1040                         nexthop->last_lookup = src->u.prefix4;
1041                         nexthop->last_lookup_time = pim_time_monotonic_usec();
1042                         nexthop->nbr = nbr;
1043                         found = 1;
1044                 }
1045                 i++;
1046         }
1047
1048         if (found)
1049                 return 1;
1050         else
1051                 return 0;
1052 }
1053
1054 int pim_ecmp_fib_lookup_if_vif_index(struct pim_instance *pim,
1055                                      struct prefix *src, struct prefix *grp)
1056 {
1057         struct pim_nexthop nhop;
1058         int vif_index;
1059         ifindex_t ifindex;
1060         char addr_str[PREFIX_STRLEN];
1061
1062         if (PIM_DEBUG_PIM_NHT)
1063                 pim_inet4_dump("<addr?>", src->u.prefix4, addr_str,
1064                                sizeof(addr_str));
1065
1066         memset(&nhop, 0, sizeof(nhop));
1067         if (!pim_ecmp_nexthop_lookup(pim, &nhop, src, grp, 1)) {
1068                 if (PIM_DEBUG_PIM_NHT)
1069                         zlog_debug(
1070                                 "%s: could not find nexthop ifindex for address %s(%s)",
1071                                 __func__, addr_str, pim->vrf->name);
1072                 return -1;
1073         }
1074
1075         ifindex = nhop.interface->ifindex;
1076         if (PIM_DEBUG_PIM_NHT)
1077                 zlog_debug(
1078                         "%s: found nexthop ifindex=%d (interface %s(%s)) for address %s",
1079                         __func__, ifindex,
1080                         ifindex2ifname(ifindex, pim->vrf->vrf_id),
1081                         pim->vrf->name, addr_str);
1082
1083         vif_index = pim_if_find_vifindex_by_ifindex(pim, ifindex);
1084
1085         if (vif_index < 0) {
1086                 if (PIM_DEBUG_PIM_NHT) {
1087                         zlog_debug(
1088                                 "%s: low vif_index=%d(%s) < 1 nexthop for address %s",
1089                                 __func__, vif_index, pim->vrf->name, addr_str);
1090                 }
1091                 return -2;
1092         }
1093
1094         return vif_index;
1095 }