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[MULTIPATH_NUM];
  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) * MULTIPATH_NUM);
  96         num_ifindex = zclient_lookup_nexthop(pim, nexthop_tab, MULTIPATH_NUM,
  97                                              addr, PIM_NEXTHOP_LOOKUP_MAX);
  98         if (num_ifindex < 1) {
  99                 zlog_warn(
 100                         "%s %s: could not find nexthop ifindex for address %pPAs",
 101                         __FILE__, __func__, &addr);
 102                 return false;
 103         }
 104
 105         while (!found && (i < num_ifindex)) {
 106                 first_ifindex = nexthop_tab[i].ifindex;
 107
 108                 ifp = if_lookup_by_index(first_ifindex, pim->vrf->vrf_id);
 109                 if (!ifp) {
 110                         if (PIM_DEBUG_ZEBRA)
 111                                 zlog_debug(
 112                                         "%s %s: could not find interface for ifindex %d (address %pPAs)",
 113                                         __FILE__, __func__, first_ifindex,
 114                                         &addr);
 115                         i++;
 116                         continue;
 117                 }
 118
 119                 if (!ifp->info) {
 120                         if (PIM_DEBUG_ZEBRA)
 121                                 zlog_debug(
 122                                         "%s: multicast not enabled on input interface %s (ifindex=%d, RPF for source %pPAs)",
 123                                         __func__, ifp->name, first_ifindex,
 124                                         &addr);
 125                         i++;
 126                 } else if (neighbor_needed
 127                            && !pim_if_connected_to_source(ifp, addr)) {
 128                         nbr = pim_neighbor_find(ifp,
 129                                                 nexthop_tab[i].nexthop_addr);
 130                         if (PIM_DEBUG_PIM_TRACE_DETAIL)
 131                                 zlog_debug("ifp name: %s, pim nbr: %p",
 132                                            ifp->name, nbr);
 133                         if (!nbr && !if_is_loopback(ifp))
 134                                 i++;
 135                         else
 136                                 found = 1;
 137                 } else
 138                         found = 1;
 139         }
 140
 141         if (found) {
 142                 if (PIM_DEBUG_ZEBRA)
 143                         zlog_debug(
 144                                 "%s %s: found nexthop %pPAs for address %pPAs: interface %s ifindex=%d metric=%d pref=%d",
 145                                 __FILE__, __func__,
 146                                 &nexthop_tab[i].nexthop_addr, &addr, ifp->name,
 147                                 first_ifindex, nexthop_tab[i].route_metric,
 148                                 nexthop_tab[i].protocol_distance);
 149
 150                 /* update nexthop data */
 151                 nexthop->interface = ifp;
 152                 nexthop->mrib_nexthop_addr = nexthop_tab[i].nexthop_addr;
 153                 nexthop->mrib_metric_preference =
 154                         nexthop_tab[i].protocol_distance;
 155                 nexthop->mrib_route_metric = nexthop_tab[i].route_metric;
 156                 nexthop->last_lookup = addr;
 157                 nexthop->last_lookup_time = pim_time_monotonic_usec();
 158                 nexthop->nbr = nbr;
 159                 return true;
 160         } else
 161                 return false;
 162 }
 163
 164 static int nexthop_mismatch(const struct pim_nexthop *nh1,
 165                             const struct pim_nexthop *nh2)
 166 {
 167         return (nh1->interface != nh2->interface) ||
 168                (pim_addr_cmp(nh1->mrib_nexthop_addr, nh2->mrib_nexthop_addr)) ||
 169                (nh1->mrib_metric_preference != nh2->mrib_metric_preference) ||
 170                (nh1->mrib_route_metric != nh2->mrib_route_metric);
 171 }
 172
 173 static void pim_rpf_cost_change(struct pim_instance *pim,
 174                 struct pim_upstream *up, uint32_t old_cost)
 175 {
 176         struct pim_rpf *rpf = &up->rpf;
 177         uint32_t new_cost;
 178
 179         new_cost = pim_up_mlag_local_cost(up);
 180         if (PIM_DEBUG_MLAG)
 181                 zlog_debug(
 182                         "%s: Cost_to_rp of upstream-%s changed to:%u, from:%u",
 183                         __func__, up->sg_str, new_cost, old_cost);
 184
 185         if (old_cost == new_cost)
 186                 return;
 187
 188         /* Cost changed, it might Impact MLAG DF election, update */
 189         if (PIM_DEBUG_MLAG)
 190                 zlog_debug(
 191                         "%s: Cost_to_rp of upstream-%s changed to:%u",
 192                         __func__, up->sg_str,
 193                         rpf->source_nexthop.mrib_route_metric);
 194
 195         if (pim_up_mlag_is_local(up))
 196                 pim_mlag_up_local_add(pim, up);
 197 }
 198
 199 enum pim_rpf_result pim_rpf_update(struct pim_instance *pim,
 200                 struct pim_upstream *up, struct pim_rpf *old,
 201                 const char *caller)
 202 {
 203         struct pim_rpf *rpf = &up->rpf;
 204         struct pim_rpf saved;
 205         struct prefix nht_p;
 206         struct prefix src, grp;
 207         bool neigh_needed = true;
 208         uint32_t saved_mrib_route_metric;
 209         pim_addr rpf_addr;
 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         pim_addr_to_prefix(&nht_p, up->upstream_addr);
 229
 230         pim_addr_to_prefix(&src, up->upstream_addr); // RP or Src address
 231         pim_addr_to_prefix(&grp, up->sg.grp);
 232
 233         if ((pim_addr_is_any(up->sg.src) && I_am_RP(pim, up->sg.grp)) ||
 234             PIM_UPSTREAM_FLAG_TEST_FHR(up->flags))
 235                 neigh_needed = false;
 236         pim_find_or_track_nexthop(pim, &nht_p, up, NULL, NULL);
 237         if (!pim_ecmp_nexthop_lookup(pim, &rpf->source_nexthop, &src, &grp,
 238                                 neigh_needed)) {
 239                 /* Route is Deleted in Zebra, reset the stored NH data */
 240                 pim_upstream_rpf_clear(pim, up);
 241                 pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 242                 return PIM_RPF_FAILURE;
 243         }
 244
 245         rpf_addr = pim_rpf_find_rpf_addr(up);
 246         pim_addr_to_prefix(&rpf->rpf_addr, rpf_addr);
 247
 248         if (pim_rpf_addr_is_inaddr_any(rpf) && PIM_DEBUG_ZEBRA) {
 249                 /* RPF'(S,G) not found */
 250                 zlog_debug("%s(%s): RPF'%s not found: won't send join upstream",
 251                            __func__, caller, up->sg_str);
 252                 /* warning only */
 253         }
 254
 255         /* detect change in pim_nexthop */
 256         if (nexthop_mismatch(&rpf->source_nexthop, &saved.source_nexthop)) {
 257
 258                 if (PIM_DEBUG_ZEBRA)
 259                         zlog_debug("%s(%s): (S,G)=%s source nexthop now is: interface=%s address=%pPAs pref=%d metric=%d",
 260                  __func__, caller,
 261                  up->sg_str,
 262                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
 263                  &rpf->source_nexthop.mrib_nexthop_addr,
 264                  rpf->source_nexthop.mrib_metric_preference,
 265                  rpf->source_nexthop.mrib_route_metric);
 266
 267                 pim_upstream_update_join_desired(pim, up);
 268                 pim_upstream_update_could_assert(up);
 269                 pim_upstream_update_my_assert_metric(up);
 270         }
 271
 272         /* detect change in RPF_interface(S) */
 273         if (saved.source_nexthop.interface != rpf->source_nexthop.interface) {
 274
 275                 if (PIM_DEBUG_ZEBRA) {
 276                         zlog_debug("%s(%s): (S,G)=%s RPF_interface(S) changed from %s to %s",
 277                  __func__, caller,
 278                  up->sg_str,
 279                  saved.source_nexthop.interface ? saved.source_nexthop.interface->name : "<oldif?>",
 280                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
 281                         /* warning only */
 282                 }
 283
 284                 pim_upstream_rpf_interface_changed(
 285                         up, saved.source_nexthop.interface);
 286         }
 287
 288         /* detect change in RPF'(S,G) */
 289         if (!prefix_same(&saved.rpf_addr, &rpf->rpf_addr) ||
 290             saved.source_nexthop.interface != rpf->source_nexthop.interface) {
 291                 pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 292                 return PIM_RPF_CHANGED;
 293         }
 294
 295         if (PIM_DEBUG_MLAG)
 296                 zlog_debug(
 297                         "%s(%s): Cost_to_rp of upstream-%s changed to:%u",
 298                         __func__, caller, up->sg_str,
 299                         rpf->source_nexthop.mrib_route_metric);
 300
 301         pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 302
 303         return PIM_RPF_OK;
 304 }
 305
 306 /*
 307  * In the case of RP deletion and RP unreachablity,
 308  * uninstall the mroute in the kernel and clear the
 309  * rpf information in the pim upstream and pim channel
 310  * oil data structure.
 311  */
 312 void pim_upstream_rpf_clear(struct pim_instance *pim,
 313                             struct pim_upstream *up)
 314 {
 315         if (up->rpf.source_nexthop.interface) {
 316                 pim_upstream_switch(pim, up, PIM_UPSTREAM_NOTJOINED);
 317                 up->rpf.source_nexthop.interface = NULL;
 318                 up->rpf.source_nexthop.mrib_nexthop_addr = PIMADDR_ANY;
 319                 up->rpf.source_nexthop.mrib_metric_preference =
 320                         router->infinite_assert_metric.metric_preference;
 321                 up->rpf.source_nexthop.mrib_route_metric =
 322                         router->infinite_assert_metric.route_metric;
 323                 pim_addr_to_prefix(&up->rpf.rpf_addr, PIMADDR_ANY);
 324                 pim_upstream_mroute_iif_update(up->channel_oil, __func__);
 325         }
 326 }
 327
 328 /*
 329   RFC 4601: 4.1.6.  State Summarization Macros
 330
 331      neighbor RPF'(S,G) {
 332          if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
 333               return AssertWinner(S, G, RPF_interface(S) )
 334          } else {
 335               return NBR( RPF_interface(S), MRIB.next_hop( S ) )
 336          }
 337      }
 338
 339   RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
 340   packets should be coming and to which joins should be sent on the RP
 341   tree and SPT, respectively.
 342 */
 343 static pim_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
 344 {
 345         struct pim_ifchannel *rpf_ch;
 346         struct pim_neighbor *neigh;
 347         pim_addr rpf_addr;
 348
 349         if (!up->rpf.source_nexthop.interface) {
 350                 zlog_warn("%s: missing RPF interface for upstream (S,G)=%s",
 351                           __func__, up->sg_str);
 352
 353                 return PIMADDR_ANY;
 354         }
 355
 356         rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface, &up->sg);
 357         if (rpf_ch) {
 358                 if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
 359                         return rpf_ch->ifassert_winner;
 360                 }
 361         }
 362
 363         /* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */
 364
 365         neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
 366                                      up->rpf.source_nexthop.mrib_nexthop_addr);
 367         if (neigh)
 368                 rpf_addr = neigh->source_addr;
 369         else
 370                 rpf_addr = PIMADDR_ANY;
 371
 372         return rpf_addr;
 373 }
 374
 375 int pim_rpf_addr_is_inaddr_any(struct pim_rpf *rpf)
 376 {
 377         pim_addr rpf_addr = pim_addr_from_prefix(&rpf->rpf_addr);
 378
 379         switch (rpf->rpf_addr.family) {
 380         case AF_INET:
 381         case AF_INET6:
 382                 return pim_addr_is_any(rpf_addr);
 383         default:
 384                 return 0;
 385         }
 386 }
 387
 388 int pim_rpf_is_same(struct pim_rpf *rpf1, struct pim_rpf *rpf2)
 389 {
 390         if (rpf1->source_nexthop.interface == rpf2->source_nexthop.interface)
 391                 return 1;
 392
 393         return 0;
 394 }
 395
 396 unsigned int pim_rpf_hash_key(const void *arg)
 397 {
 398         const struct pim_nexthop_cache *r = arg;
 399
 400 #if PIM_IPV == 4
 401         return jhash_1word(r->rpf.rpf_addr.u.prefix4.s_addr, 0);
 402 #else
 403         return jhash2(r->rpf.rpf_addr.u.prefix6.s6_addr32,
 404                       array_size(r->rpf.rpf_addr.u.prefix6.s6_addr32), 0);
 405 #endif
 406 }
 407
 408 bool pim_rpf_equal(const void *arg1, const void *arg2)
 409 {
 410         const struct pim_nexthop_cache *r1 =
 411                 (const struct pim_nexthop_cache *)arg1;
 412         const struct pim_nexthop_cache *r2 =
 413                 (const struct pim_nexthop_cache *)arg2;
 414
 415         return prefix_same(&r1->rpf.rpf_addr, &r2->rpf.rpf_addr);
 416 }