pimd/pim_rpf.c

   1 /*
   2  * PIM for Quagga
   3  * Copyright (C) 2008  Everton da Silva Marques
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include <zebra.h>
  21
  22 #include "if.h"
  23
  24 #include "log.h"
  25 #include "prefix.h"
  26 #include "memory.h"
  27 #include "jhash.h"
  28
  29 #include "pimd.h"
  30 #include "pim_rpf.h"
  31 #include "pim_pim.h"
  32 #include "pim_str.h"
  33 #include "pim_iface.h"
  34 #include "pim_neighbor.h"
  35 #include "pim_zlookup.h"
  36 #include "pim_ifchannel.h"
  37 #include "pim_time.h"
  38 #include "pim_nht.h"
  39 #include "pim_oil.h"
  40 #include "pim_mlag.h"
  41
  42 static pim_addr pim_rpf_find_rpf_addr(struct pim_upstream *up);
  43
  44 void pim_rpf_set_refresh_time(struct pim_instance *pim)
  45 {
  46         pim->last_route_change_time = pim_time_monotonic_usec();
  47         if (PIM_DEBUG_PIM_TRACE)
  48                 zlog_debug("%s: vrf(%s) New last route change time: %" PRId64,
  49                            __func__, pim->vrf->name,
  50                            pim->last_route_change_time);
  51 }
  52
  53 bool pim_nexthop_lookup(struct pim_instance *pim, struct pim_nexthop *nexthop,
  54                         pim_addr addr, int neighbor_needed)
  55 {
  56         struct pim_zlookup_nexthop nexthop_tab[MULTIPATH_NUM];
  57         struct pim_neighbor *nbr = NULL;
  58         int num_ifindex;
  59         struct interface *ifp = NULL;
  60         ifindex_t first_ifindex = 0;
  61         int found = 0;
  62         int i = 0;
  63
  64 #if PIM_IPV == 4
  65         /*
  66          * We should not attempt to lookup a
  67          * 255.255.255.255 address, since
  68          * it will never work
  69          */
  70         if (pim_addr_is_any(addr))
  71                 return false;
  72 #endif
  73
  74         if ((!pim_addr_cmp(nexthop->last_lookup, addr)) &&
  75             (nexthop->last_lookup_time > pim->last_route_change_time)) {
  76                 if (PIM_DEBUG_PIM_NHT)
  77                         zlog_debug(
  78                                 "%s: Using last lookup for %pPAs at %lld, %" PRId64
  79                                 " addr %pPAs",
  80                                 __func__, &addr, nexthop->last_lookup_time,
  81                                 pim->last_route_change_time,
  82                                 &nexthop->mrib_nexthop_addr);
  83                 pim->nexthop_lookups_avoided++;
  84                 return true;
  85         } else {
  86                 if (PIM_DEBUG_PIM_NHT)
  87                         zlog_debug(
  88                                 "%s: Looking up: %pPAs, last lookup time: %lld, %" PRId64,
  89                                 __func__, &addr, nexthop->last_lookup_time,
  90                                 pim->last_route_change_time);
  91         }
  92
  93         memset(nexthop_tab, 0,
  94                sizeof(struct pim_zlookup_nexthop) * MULTIPATH_NUM);
  95         num_ifindex = zclient_lookup_nexthop(pim, nexthop_tab, MULTIPATH_NUM,
  96                                              addr, PIM_NEXTHOP_LOOKUP_MAX);
  97         if (num_ifindex < 1) {
  98                 zlog_warn(
  99                         "%s %s: could not find nexthop ifindex for address %pPAs",
 100                         __FILE__, __func__, &addr);
 101                 return false;
 102         }
 103
 104         while (!found && (i < num_ifindex)) {
 105                 first_ifindex = nexthop_tab[i].ifindex;
 106
 107                 ifp = if_lookup_by_index(first_ifindex, pim->vrf->vrf_id);
 108                 if (!ifp) {
 109                         if (PIM_DEBUG_ZEBRA)
 110                                 zlog_debug(
 111                                         "%s %s: could not find interface for ifindex %d (address %pPAs)",
 112                                         __FILE__, __func__, first_ifindex,
 113                                         &addr);
 114                         i++;
 115                         continue;
 116                 }
 117
 118                 if (!ifp->info) {
 119                         if (PIM_DEBUG_ZEBRA)
 120                                 zlog_debug(
 121                                         "%s: multicast not enabled on input interface %s (ifindex=%d, RPF for source %pPAs)",
 122                                         __func__, ifp->name, first_ifindex,
 123                                         &addr);
 124                         i++;
 125                 } else if (neighbor_needed
 126                            && !pim_if_connected_to_source(ifp, addr)) {
 127                         nbr = pim_neighbor_find(ifp,
 128                                                 nexthop_tab[i].nexthop_addr);
 129                         if (PIM_DEBUG_PIM_TRACE_DETAIL)
 130                                 zlog_debug("ifp name: %s, pim nbr: %p",
 131                                            ifp->name, nbr);
 132                         if (!nbr && !if_is_loopback(ifp))
 133                                 i++;
 134                         else
 135                                 found = 1;
 136                 } else
 137                         found = 1;
 138         }
 139
 140         if (found) {
 141                 if (PIM_DEBUG_ZEBRA)
 142                         zlog_debug(
 143                                 "%s %s: found nexthop %pPAs for address %pPAs: interface %s ifindex=%d metric=%d pref=%d",
 144                                 __FILE__, __func__,
 145                                 &nexthop_tab[i].nexthop_addr, &addr, ifp->name,
 146                                 first_ifindex, nexthop_tab[i].route_metric,
 147                                 nexthop_tab[i].protocol_distance);
 148
 149                 /* update nexthop data */
 150                 nexthop->interface = ifp;
 151                 nexthop->mrib_nexthop_addr = nexthop_tab[i].nexthop_addr;
 152                 nexthop->mrib_metric_preference =
 153                         nexthop_tab[i].protocol_distance;
 154                 nexthop->mrib_route_metric = nexthop_tab[i].route_metric;
 155                 nexthop->last_lookup = addr;
 156                 nexthop->last_lookup_time = pim_time_monotonic_usec();
 157                 nexthop->nbr = nbr;
 158                 return true;
 159         } else
 160                 return false;
 161 }
 162
 163 static int nexthop_mismatch(const struct pim_nexthop *nh1,
 164                             const struct pim_nexthop *nh2)
 165 {
 166         return (nh1->interface != nh2->interface) ||
 167                (pim_addr_cmp(nh1->mrib_nexthop_addr, nh2->mrib_nexthop_addr)) ||
 168                (nh1->mrib_metric_preference != nh2->mrib_metric_preference) ||
 169                (nh1->mrib_route_metric != nh2->mrib_route_metric);
 170 }
 171
 172 static void pim_rpf_cost_change(struct pim_instance *pim,
 173                 struct pim_upstream *up, uint32_t old_cost)
 174 {
 175         struct pim_rpf *rpf = &up->rpf;
 176         uint32_t new_cost;
 177
 178         new_cost = pim_up_mlag_local_cost(up);
 179         if (PIM_DEBUG_MLAG)
 180                 zlog_debug(
 181                         "%s: Cost_to_rp of upstream-%s changed to:%u, from:%u",
 182                         __func__, up->sg_str, new_cost, old_cost);
 183
 184         if (old_cost == new_cost)
 185                 return;
 186
 187         /* Cost changed, it might Impact MLAG DF election, update */
 188         if (PIM_DEBUG_MLAG)
 189                 zlog_debug(
 190                         "%s: Cost_to_rp of upstream-%s changed to:%u",
 191                         __func__, up->sg_str,
 192                         rpf->source_nexthop.mrib_route_metric);
 193
 194         if (pim_up_mlag_is_local(up))
 195                 pim_mlag_up_local_add(pim, up);
 196 }
 197
 198 enum pim_rpf_result pim_rpf_update(struct pim_instance *pim,
 199                 struct pim_upstream *up, struct pim_rpf *old,
 200                 const char *caller)
 201 {
 202         struct pim_rpf *rpf = &up->rpf;
 203         struct pim_rpf saved;
 204         struct prefix nht_p;
 205         struct prefix src, grp;
 206         bool neigh_needed = true;
 207         uint32_t saved_mrib_route_metric;
 208         pim_addr rpf_addr;
 209
 210         if (PIM_UPSTREAM_FLAG_TEST_STATIC_IIF(up->flags))
 211                 return PIM_RPF_OK;
 212
 213         if (pim_addr_is_any(up->upstream_addr)) {
 214                 zlog_debug("%s(%s): RP is not configured yet for %s",
 215                         __func__, caller, up->sg_str);
 216                 return PIM_RPF_OK;
 217         }
 218
 219         saved.source_nexthop = rpf->source_nexthop;
 220         saved.rpf_addr = rpf->rpf_addr;
 221         saved_mrib_route_metric = pim_up_mlag_local_cost(up);
 222         if (old) {
 223                 old->source_nexthop = saved.source_nexthop;
 224                 old->rpf_addr = saved.rpf_addr;
 225         }
 226
 227         pim_addr_to_prefix(&nht_p, up->upstream_addr);
 228
 229         pim_addr_to_prefix(&src, up->upstream_addr); // RP or Src address
 230         pim_addr_to_prefix(&grp, up->sg.grp);
 231
 232         if ((pim_addr_is_any(up->sg.src) && I_am_RP(pim, up->sg.grp)) ||
 233             PIM_UPSTREAM_FLAG_TEST_FHR(up->flags))
 234                 neigh_needed = false;
 235         pim_find_or_track_nexthop(pim, &nht_p, up, NULL, NULL);
 236         if (!pim_ecmp_nexthop_lookup(pim, &rpf->source_nexthop, &src, &grp,
 237                                 neigh_needed)) {
 238                 /* Route is Deleted in Zebra, reset the stored NH data */
 239                 pim_upstream_rpf_clear(pim, up);
 240                 pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 241                 return PIM_RPF_FAILURE;
 242         }
 243
 244         rpf_addr = pim_rpf_find_rpf_addr(up);
 245         pim_addr_to_prefix(&rpf->rpf_addr, rpf_addr);
 246
 247         if (pim_rpf_addr_is_inaddr_any(rpf) && PIM_DEBUG_ZEBRA) {
 248                 /* RPF'(S,G) not found */
 249                 zlog_debug("%s(%s): RPF'%s not found: won't send join upstream",
 250                            __func__, caller, up->sg_str);
 251                 /* warning only */
 252         }
 253
 254         /* detect change in pim_nexthop */
 255         if (nexthop_mismatch(&rpf->source_nexthop, &saved.source_nexthop)) {
 256
 257                 if (PIM_DEBUG_ZEBRA)
 258                         zlog_debug("%s(%s): (S,G)=%s source nexthop now is: interface=%s address=%pPAs pref=%d metric=%d",
 259                  __func__, caller,
 260                  up->sg_str,
 261                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
 262                  &rpf->source_nexthop.mrib_nexthop_addr,
 263                  rpf->source_nexthop.mrib_metric_preference,
 264                  rpf->source_nexthop.mrib_route_metric);
 265
 266                 pim_upstream_update_join_desired(pim, up);
 267                 pim_upstream_update_could_assert(up);
 268                 pim_upstream_update_my_assert_metric(up);
 269         }
 270
 271         /* detect change in RPF_interface(S) */
 272         if (saved.source_nexthop.interface != rpf->source_nexthop.interface) {
 273
 274                 if (PIM_DEBUG_ZEBRA) {
 275                         zlog_debug("%s(%s): (S,G)=%s RPF_interface(S) changed from %s to %s",
 276                  __func__, caller,
 277                  up->sg_str,
 278                  saved.source_nexthop.interface ? saved.source_nexthop.interface->name : "<oldif?>",
 279                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
 280                         /* warning only */
 281                 }
 282
 283                 pim_upstream_rpf_interface_changed(
 284                         up, saved.source_nexthop.interface);
 285         }
 286
 287         /* detect change in RPF'(S,G) */
 288         if (!prefix_same(&saved.rpf_addr, &rpf->rpf_addr) ||
 289             saved.source_nexthop.interface != rpf->source_nexthop.interface) {
 290                 pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 291                 return PIM_RPF_CHANGED;
 292         }
 293
 294         if (PIM_DEBUG_MLAG)
 295                 zlog_debug(
 296                         "%s(%s): Cost_to_rp of upstream-%s changed to:%u",
 297                         __func__, caller, up->sg_str,
 298                         rpf->source_nexthop.mrib_route_metric);
 299
 300         pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 301
 302         return PIM_RPF_OK;
 303 }
 304
 305 /*
 306  * In the case of RP deletion and RP unreachablity,
 307  * uninstall the mroute in the kernel and clear the
 308  * rpf information in the pim upstream and pim channel
 309  * oil data structure.
 310  */
 311 void pim_upstream_rpf_clear(struct pim_instance *pim,
 312                             struct pim_upstream *up)
 313 {
 314         if (up->rpf.source_nexthop.interface) {
 315                 pim_upstream_switch(pim, up, PIM_UPSTREAM_NOTJOINED);
 316                 up->rpf.source_nexthop.interface = NULL;
 317                 up->rpf.source_nexthop.mrib_nexthop_addr = PIMADDR_ANY;
 318                 up->rpf.source_nexthop.mrib_metric_preference =
 319                         router->infinite_assert_metric.metric_preference;
 320                 up->rpf.source_nexthop.mrib_route_metric =
 321                         router->infinite_assert_metric.route_metric;
 322                 pim_addr_to_prefix(&up->rpf.rpf_addr, PIMADDR_ANY);
 323                 pim_upstream_mroute_iif_update(up->channel_oil, __func__);
 324         }
 325 }
 326
 327 /*
 328   RFC 4601: 4.1.6.  State Summarization Macros
 329
 330      neighbor RPF'(S,G) {
 331          if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
 332               return AssertWinner(S, G, RPF_interface(S) )
 333          } else {
 334               return NBR( RPF_interface(S), MRIB.next_hop( S ) )
 335          }
 336      }
 337
 338   RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
 339   packets should be coming and to which joins should be sent on the RP
 340   tree and SPT, respectively.
 341 */
 342 static pim_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
 343 {
 344         struct pim_ifchannel *rpf_ch;
 345         struct pim_neighbor *neigh;
 346         pim_addr rpf_addr;
 347
 348         if (!up->rpf.source_nexthop.interface) {
 349                 zlog_warn("%s: missing RPF interface for upstream (S,G)=%s",
 350                           __func__, up->sg_str);
 351
 352                 return PIMADDR_ANY;
 353         }
 354
 355         rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface, &up->sg);
 356         if (rpf_ch) {
 357                 if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
 358                         return rpf_ch->ifassert_winner;
 359                 }
 360         }
 361
 362         /* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */
 363
 364         neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
 365                                      up->rpf.source_nexthop.mrib_nexthop_addr);
 366         if (neigh)
 367                 rpf_addr = neigh->source_addr;
 368         else
 369                 rpf_addr = PIMADDR_ANY;
 370
 371         return rpf_addr;
 372 }
 373
 374 int pim_rpf_addr_is_inaddr_any(struct pim_rpf *rpf)
 375 {
 376         pim_addr rpf_addr = pim_addr_from_prefix(&rpf->rpf_addr);
 377
 378         switch (rpf->rpf_addr.family) {
 379         case AF_INET:
 380         case AF_INET6:
 381                 return pim_addr_is_any(rpf_addr);
 382         default:
 383                 return 0;
 384         }
 385 }
 386
 387 int pim_rpf_is_same(struct pim_rpf *rpf1, struct pim_rpf *rpf2)
 388 {
 389         if (rpf1->source_nexthop.interface == rpf2->source_nexthop.interface)
 390                 return 1;
 391
 392         return 0;
 393 }
 394
 395 unsigned int pim_rpf_hash_key(const void *arg)
 396 {
 397         const struct pim_nexthop_cache *r = arg;
 398
 399 #if PIM_IPV == 4
 400         return jhash_1word(r->rpf.rpf_addr.u.prefix4.s_addr, 0);
 401 #else
 402         return jhash2(r->rpf.rpf_addr.u.prefix6.s6_addr32,
 403                       array_size(r->rpf.rpf_addr.u.prefix6.s6_addr32), 0);
 404 #endif
 405 }
 406
 407 bool pim_rpf_equal(const void *arg1, const void *arg2)
 408 {
 409         const struct pim_nexthop_cache *r1 =
 410                 (const struct pim_nexthop_cache *)arg1;
 411         const struct pim_nexthop_cache *r2 =
 412                 (const struct pim_nexthop_cache *)arg2;
 413
 414         return prefix_same(&r1->rpf.rpf_addr, &r2->rpf.rpf_addr);
 415 }