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                 if (PIM_DEBUG_PIM_NHT)
 101                         zlog_debug(
 102                                 "%s %s: could not find nexthop ifindex for address %pPAs",
 103                                 __FILE__, __func__, &addr);
 104                 return false;
 105         }
 106
 107         while (!found && (i < num_ifindex)) {
 108                 first_ifindex = nexthop_tab[i].ifindex;
 109
 110                 ifp = if_lookup_by_index(first_ifindex, pim->vrf->vrf_id);
 111                 if (!ifp) {
 112                         if (PIM_DEBUG_ZEBRA)
 113                                 zlog_debug(
 114                                         "%s %s: could not find interface for ifindex %d (address %pPAs)",
 115                                         __FILE__, __func__, first_ifindex,
 116                                         &addr);
 117                         i++;
 118                         continue;
 119                 }
 120
 121                 if (!ifp->info) {
 122                         if (PIM_DEBUG_ZEBRA)
 123                                 zlog_debug(
 124                                         "%s: multicast not enabled on input interface %s (ifindex=%d, RPF for source %pPAs)",
 125                                         __func__, ifp->name, first_ifindex,
 126                                         &addr);
 127                         i++;
 128                 } else if (neighbor_needed
 129                            && !pim_if_connected_to_source(ifp, addr)) {
 130                         nbr = pim_neighbor_find(ifp,
 131                                                 nexthop_tab[i].nexthop_addr);
 132                         if (PIM_DEBUG_PIM_TRACE_DETAIL)
 133                                 zlog_debug("ifp name: %s, pim nbr: %p",
 134                                            ifp->name, nbr);
 135                         if (!nbr && !if_is_loopback(ifp))
 136                                 i++;
 137                         else
 138                                 found = 1;
 139                 } else
 140                         found = 1;
 141         }
 142
 143         if (found) {
 144                 if (PIM_DEBUG_ZEBRA)
 145                         zlog_debug(
 146                                 "%s %s: found nexthop %pPAs for address %pPAs: interface %s ifindex=%d metric=%d pref=%d",
 147                                 __FILE__, __func__,
 148                                 &nexthop_tab[i].nexthop_addr, &addr, ifp->name,
 149                                 first_ifindex, nexthop_tab[i].route_metric,
 150                                 nexthop_tab[i].protocol_distance);
 151
 152                 /* update nexthop data */
 153                 nexthop->interface = ifp;
 154                 nexthop->mrib_nexthop_addr = nexthop_tab[i].nexthop_addr;
 155                 nexthop->mrib_metric_preference =
 156                         nexthop_tab[i].protocol_distance;
 157                 nexthop->mrib_route_metric = nexthop_tab[i].route_metric;
 158                 nexthop->last_lookup = addr;
 159                 nexthop->last_lookup_time = pim_time_monotonic_usec();
 160                 nexthop->nbr = nbr;
 161                 return true;
 162         } else
 163                 return false;
 164 }
 165
 166 static int nexthop_mismatch(const struct pim_nexthop *nh1,
 167                             const struct pim_nexthop *nh2)
 168 {
 169         return (nh1->interface != nh2->interface) ||
 170                (pim_addr_cmp(nh1->mrib_nexthop_addr, nh2->mrib_nexthop_addr)) ||
 171                (nh1->mrib_metric_preference != nh2->mrib_metric_preference) ||
 172                (nh1->mrib_route_metric != nh2->mrib_route_metric);
 173 }
 174
 175 static void pim_rpf_cost_change(struct pim_instance *pim,
 176                 struct pim_upstream *up, uint32_t old_cost)
 177 {
 178         struct pim_rpf *rpf = &up->rpf;
 179         uint32_t new_cost;
 180
 181         new_cost = pim_up_mlag_local_cost(up);
 182         if (PIM_DEBUG_MLAG)
 183                 zlog_debug(
 184                         "%s: Cost_to_rp of upstream-%s changed to:%u, from:%u",
 185                         __func__, up->sg_str, new_cost, old_cost);
 186
 187         if (old_cost == new_cost)
 188                 return;
 189
 190         /* Cost changed, it might Impact MLAG DF election, update */
 191         if (PIM_DEBUG_MLAG)
 192                 zlog_debug(
 193                         "%s: Cost_to_rp of upstream-%s changed to:%u",
 194                         __func__, up->sg_str,
 195                         rpf->source_nexthop.mrib_route_metric);
 196
 197         if (pim_up_mlag_is_local(up))
 198                 pim_mlag_up_local_add(pim, up);
 199 }
 200
 201 enum pim_rpf_result pim_rpf_update(struct pim_instance *pim,
 202                 struct pim_upstream *up, struct pim_rpf *old,
 203                 const char *caller)
 204 {
 205         struct pim_rpf *rpf = &up->rpf;
 206         struct pim_rpf saved;
 207         pim_addr src;
 208         struct prefix grp;
 209         bool neigh_needed = true;
 210         uint32_t saved_mrib_route_metric;
 211
 212         if (PIM_UPSTREAM_FLAG_TEST_STATIC_IIF(up->flags))
 213                 return PIM_RPF_OK;
 214
 215         if (pim_addr_is_any(up->upstream_addr)) {
 216                 zlog_debug("%s(%s): RP is not configured yet for %s",
 217                         __func__, caller, up->sg_str);
 218                 return PIM_RPF_OK;
 219         }
 220
 221         saved.source_nexthop = rpf->source_nexthop;
 222         saved.rpf_addr = rpf->rpf_addr;
 223         saved_mrib_route_metric = pim_up_mlag_local_cost(up);
 224         if (old) {
 225                 old->source_nexthop = saved.source_nexthop;
 226                 old->rpf_addr = saved.rpf_addr;
 227         }
 228
 229         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, up->upstream_addr, 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->rpf_addr = pim_rpf_find_rpf_addr(up);
 245
 246         if (pim_rpf_addr_is_inaddr_any(rpf) && PIM_DEBUG_ZEBRA) {
 247                 /* RPF'(S,G) not found */
 248                 zlog_debug("%s(%s): RPF'%s not found: won't send join upstream",
 249                            __func__, caller, up->sg_str);
 250                 /* warning only */
 251         }
 252
 253         /* detect change in pim_nexthop */
 254         if (nexthop_mismatch(&rpf->source_nexthop, &saved.source_nexthop)) {
 255
 256                 if (PIM_DEBUG_ZEBRA)
 257                         zlog_debug("%s(%s): (S,G)=%s source nexthop now is: interface=%s address=%pPAs pref=%d metric=%d",
 258                  __func__, caller,
 259                  up->sg_str,
 260                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
 261                  &rpf->source_nexthop.mrib_nexthop_addr,
 262                  rpf->source_nexthop.mrib_metric_preference,
 263                  rpf->source_nexthop.mrib_route_metric);
 264
 265                 pim_upstream_update_join_desired(pim, up);
 266                 pim_upstream_update_could_assert(up);
 267                 pim_upstream_update_my_assert_metric(up);
 268         }
 269
 270         /* detect change in RPF_interface(S) */
 271         if (saved.source_nexthop.interface != rpf->source_nexthop.interface) {
 272
 273                 if (PIM_DEBUG_ZEBRA) {
 274                         zlog_debug("%s(%s): (S,G)=%s RPF_interface(S) changed from %s to %s",
 275                  __func__, caller,
 276                  up->sg_str,
 277                  saved.source_nexthop.interface ? saved.source_nexthop.interface->name : "<oldif?>",
 278                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
 279                         /* warning only */
 280                 }
 281
 282                 pim_upstream_rpf_interface_changed(
 283                         up, saved.source_nexthop.interface);
 284         }
 285
 286         /* detect change in RPF'(S,G) */
 287         if (pim_addr_cmp(saved.rpf_addr, rpf->rpf_addr) ||
 288             saved.source_nexthop.interface != rpf->source_nexthop.interface) {
 289                 pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 290                 return PIM_RPF_CHANGED;
 291         }
 292
 293         if (PIM_DEBUG_MLAG)
 294                 zlog_debug(
 295                         "%s(%s): Cost_to_rp of upstream-%s changed to:%u",
 296                         __func__, caller, up->sg_str,
 297                         rpf->source_nexthop.mrib_route_metric);
 298
 299         pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
 300
 301         return PIM_RPF_OK;
 302 }
 303
 304 /*
 305  * In the case of RP deletion and RP unreachablity,
 306  * uninstall the mroute in the kernel and clear the
 307  * rpf information in the pim upstream and pim channel
 308  * oil data structure.
 309  */
 310 void pim_upstream_rpf_clear(struct pim_instance *pim,
 311                             struct pim_upstream *up)
 312 {
 313         if (up->rpf.source_nexthop.interface) {
 314                 pim_upstream_switch(pim, up, PIM_UPSTREAM_NOTJOINED);
 315                 up->rpf.source_nexthop.interface = NULL;
 316                 up->rpf.source_nexthop.mrib_nexthop_addr = PIMADDR_ANY;
 317                 up->rpf.source_nexthop.mrib_metric_preference =
 318                         router->infinite_assert_metric.metric_preference;
 319                 up->rpf.source_nexthop.mrib_route_metric =
 320                         router->infinite_assert_metric.route_metric;
 321                 up->rpf.rpf_addr = PIMADDR_ANY;
 322                 pim_upstream_mroute_iif_update(up->channel_oil, __func__);
 323         }
 324 }
 325
 326 /*
 327   RFC 4601: 4.1.6.  State Summarization Macros
 328
 329      neighbor RPF'(S,G) {
 330          if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
 331               return AssertWinner(S, G, RPF_interface(S) )
 332          } else {
 333               return NBR( RPF_interface(S), MRIB.next_hop( S ) )
 334          }
 335      }
 336
 337   RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
 338   packets should be coming and to which joins should be sent on the RP
 339   tree and SPT, respectively.
 340 */
 341 static pim_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
 342 {
 343         struct pim_ifchannel *rpf_ch;
 344         struct pim_neighbor *neigh;
 345         pim_addr rpf_addr;
 346
 347         if (!up->rpf.source_nexthop.interface) {
 348                 zlog_warn("%s: missing RPF interface for upstream (S,G)=%s",
 349                           __func__, up->sg_str);
 350
 351                 return PIMADDR_ANY;
 352         }
 353
 354         rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface, &up->sg);
 355         if (rpf_ch) {
 356                 if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
 357                         return rpf_ch->ifassert_winner;
 358                 }
 359         }
 360
 361         /* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */
 362
 363         neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
 364                                      up->rpf.source_nexthop.mrib_nexthop_addr);
 365         if (neigh)
 366                 rpf_addr = neigh->source_addr;
 367         else
 368                 rpf_addr = PIMADDR_ANY;
 369
 370         return rpf_addr;
 371 }
 372
 373 int pim_rpf_addr_is_inaddr_any(struct pim_rpf *rpf)
 374 {
 375         return pim_addr_is_any(rpf->rpf_addr);
 376 }
 377
 378 int pim_rpf_is_same(struct pim_rpf *rpf1, struct pim_rpf *rpf2)
 379 {
 380         if (rpf1->source_nexthop.interface == rpf2->source_nexthop.interface)
 381                 return 1;
 382
 383         return 0;
 384 }
 385
 386 unsigned int pim_rpf_hash_key(const void *arg)
 387 {
 388         const struct pim_nexthop_cache *r = arg;
 389
 390 #if PIM_IPV == 4
 391         return jhash_1word(r->rpf.rpf_addr.s_addr, 0);
 392 #else
 393         return jhash2(r->rpf.rpf_addr.s6_addr32,
 394                       array_size(r->rpf.rpf_addr.s6_addr32), 0);
 395 #endif
 396 }
 397
 398 bool pim_rpf_equal(const void *arg1, const void *arg2)
 399 {
 400         const struct pim_nexthop_cache *r1 =
 401                 (const struct pim_nexthop_cache *)arg1;
 402         const struct pim_nexthop_cache *r2 =
 403                 (const struct pim_nexthop_cache *)arg2;
 404
 405         return (!pim_addr_cmp(r1->rpf.rpf_addr, r2->rpf.rpf_addr));
 406 }