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