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
  16   along with this program; see the file COPYING; if not, write to the
  17   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  18   MA 02110-1301 USA
  19 */
  20
  21 #include <zebra.h>
  22
  23 #include "if.h"
  24
  25 #include "log.h"
  26 #include "prefix.h"
  27 #include "memory.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_zlookup.h"
  35 #include "pim_ifchannel.h"
  36
  37 static struct in_addr pim_rpf_find_rpf_addr(struct pim_upstream *up);
  38
  39 int pim_nexthop_lookup(struct pim_nexthop *nexthop,
  40                        struct in_addr addr, struct interface *incoming)
  41 {
  42   struct pim_zlookup_nexthop nexthop_tab[PIM_NEXTHOP_IFINDEX_TAB_SIZE];
  43   int num_ifindex;
  44   struct interface *ifp;
  45   int first_ifindex;
  46
  47   memset (nexthop_tab, 0, sizeof (struct pim_zlookup_nexthop) * PIM_NEXTHOP_IFINDEX_TAB_SIZE);
  48
  49   if (!incoming)
  50     {
  51       num_ifindex = zclient_lookup_nexthop(qpim_zclient_lookup, nexthop_tab,
  52                                            PIM_NEXTHOP_IFINDEX_TAB_SIZE,
  53                                            addr, PIM_NEXTHOP_LOOKUP_MAX);
  54       if (num_ifindex < 1) {
  55         char addr_str[100];
  56         pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  57         zlog_warn("%s %s: could not find nexthop ifindex for address %s",
  58                   __FILE__, __PRETTY_FUNCTION__,
  59                   addr_str);
  60         return -1;
  61       }
  62
  63       first_ifindex = nexthop_tab[0].ifindex;
  64
  65       if (num_ifindex > 1) {
  66         char addr_str[100];
  67         pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  68         zlog_info("%s %s: FIXME ignoring multiple nexthop ifindex'es num_ifindex=%d for address %s (using only ifindex=%d)",
  69                   __FILE__, __PRETTY_FUNCTION__,
  70                   num_ifindex, addr_str, first_ifindex);
  71         /* debug warning only, do not return */
  72       }
  73
  74       ifp = if_lookup_by_index(first_ifindex);
  75       if (!ifp) {
  76         char addr_str[100];
  77         pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  78         zlog_warn("%s %s: could not find interface for ifindex %d (address %s)",
  79                   __FILE__, __PRETTY_FUNCTION__,
  80                   first_ifindex, addr_str);
  81         return -2;
  82       }
  83     }
  84   else
  85     {
  86       ifp = incoming;
  87       first_ifindex = ifp->ifindex;
  88     }
  89
  90   if (!ifp->info) {
  91     char addr_str[100];
  92     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  93     zlog_warn("%s: multicast not enabled on input interface %s (ifindex=%d, RPF for source %s)",
  94               __PRETTY_FUNCTION__,
  95               ifp->name, first_ifindex, addr_str);
  96     /* debug warning only, do not return */
  97   }
  98
  99   if (PIM_DEBUG_PIM_TRACE) {
 100     char nexthop_str[100];
 101     char addr_str[100];
 102     pim_inet4_dump("<nexthop?>", nexthop_tab[0].nexthop_addr, nexthop_str, sizeof(nexthop_str));
 103     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
 104     zlog_debug("%s %s: found nexthop %s for address %s: interface %s ifindex=%d metric=%d pref=%d",
 105                __FILE__, __PRETTY_FUNCTION__,
 106                nexthop_str, addr_str,
 107                ifp->name, first_ifindex,
 108                nexthop_tab[0].route_metric,
 109                nexthop_tab[0].protocol_distance);
 110   }
 111
 112   /* update nextop data */
 113   nexthop->interface              = ifp;
 114   nexthop->mrib_nexthop_addr      = nexthop_tab[0].nexthop_addr;
 115   nexthop->mrib_metric_preference = nexthop_tab[0].protocol_distance;
 116   nexthop->mrib_route_metric      = nexthop_tab[0].route_metric;
 117
 118   return 0;
 119 }
 120
 121 static int nexthop_mismatch(const struct pim_nexthop *nh1,
 122                             const struct pim_nexthop *nh2)
 123 {
 124   return (nh1->interface != nh2->interface)
 125     ||
 126     (nh1->mrib_nexthop_addr.s_addr != nh2->mrib_nexthop_addr.s_addr)
 127     ||
 128     (nh1->mrib_metric_preference != nh2->mrib_metric_preference)
 129     ||
 130     (nh1->mrib_route_metric != nh2->mrib_route_metric);
 131 }
 132
 133 enum pim_rpf_result pim_rpf_update(struct pim_upstream *up,
 134                                    struct in_addr *old_rpf_addr,
 135                                    struct interface *incoming)
 136 {
 137   struct in_addr      save_rpf_addr;
 138   struct pim_nexthop  save_nexthop;
 139   struct pim_rpf     *rpf = &up->rpf;
 140
 141   save_nexthop  = rpf->source_nexthop; /* detect change in pim_nexthop */
 142   save_rpf_addr = rpf->rpf_addr;       /* detect change in RPF'(S,G) */
 143
 144   if (pim_nexthop_lookup(&rpf->source_nexthop,
 145                          up->upstream_addr, incoming)) {
 146     return PIM_RPF_FAILURE;
 147   }
 148
 149   rpf->rpf_addr = pim_rpf_find_rpf_addr(up);
 150   if (PIM_INADDR_IS_ANY(rpf->rpf_addr) && PIM_DEBUG_PIM_EVENTS) {
 151     /* RPF'(S,G) not found */
 152     char src_str[100];
 153     char grp_str[100];
 154     pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 155     pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 156     zlog_debug("%s %s: RPF'(%s,%s) not found: won't send join upstream",
 157                __FILE__, __PRETTY_FUNCTION__,
 158                src_str, grp_str);
 159     /* warning only */
 160   }
 161
 162   /* detect change in pim_nexthop */
 163   if (nexthop_mismatch(&rpf->source_nexthop, &save_nexthop)) {
 164
 165     if (PIM_DEBUG_PIM_EVENTS) {
 166       char src_str[100];
 167       char grp_str[100];
 168       char nhaddr_str[100];
 169       pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 170       pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 171       pim_inet4_dump("<addr?>", rpf->source_nexthop.mrib_nexthop_addr, nhaddr_str, sizeof(nhaddr_str));
 172       zlog_debug("%s %s: (S,G)=(%s,%s) source nexthop now is: interface=%s address=%s pref=%d metric=%d",
 173                  __FILE__, __PRETTY_FUNCTION__,
 174                  src_str, grp_str,
 175                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
 176                  nhaddr_str,
 177                  rpf->source_nexthop.mrib_metric_preference,
 178                  rpf->source_nexthop.mrib_route_metric);
 179     }
 180
 181     pim_upstream_update_join_desired(up);
 182     pim_upstream_update_could_assert(up);
 183     pim_upstream_update_my_assert_metric(up);
 184   }
 185
 186   /* detect change in RPF_interface(S) */
 187   if (save_nexthop.interface != rpf->source_nexthop.interface) {
 188
 189     if (PIM_DEBUG_PIM_EVENTS) {
 190       char src_str[100];
 191       char grp_str[100];
 192       pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 193       pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 194       zlog_debug("%s %s: (S,G)=(%s,%s) RPF_interface(S) changed from %s to %s",
 195                  __FILE__, __PRETTY_FUNCTION__,
 196                  src_str, grp_str,
 197                  save_nexthop.interface ? save_nexthop.interface->name : "<oldif?>",
 198                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
 199       /* warning only */
 200     }
 201
 202     pim_upstream_rpf_interface_changed(up, save_nexthop.interface);
 203   }
 204
 205   /* detect change in RPF'(S,G) */
 206   if (save_rpf_addr.s_addr != rpf->rpf_addr.s_addr) {
 207
 208     /* return old rpf to caller ? */
 209     if (old_rpf_addr)
 210       *old_rpf_addr = save_rpf_addr;
 211
 212     return PIM_RPF_CHANGED;
 213   }
 214
 215   return PIM_RPF_OK;
 216 }
 217
 218 /*
 219   RFC 4601: 4.1.6.  State Summarization Macros
 220
 221      neighbor RPF'(S,G) {
 222          if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
 223               return AssertWinner(S, G, RPF_interface(S) )
 224          } else {
 225               return NBR( RPF_interface(S), MRIB.next_hop( S ) )
 226          }
 227      }
 228
 229   RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
 230   packets should be coming and to which joins should be sent on the RP
 231   tree and SPT, respectively.
 232 */
 233 static struct in_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
 234 {
 235   struct pim_ifchannel *rpf_ch;
 236   struct pim_neighbor *neigh;
 237   struct in_addr rpf_addr;
 238
 239   if (!up->rpf.source_nexthop.interface) {
 240     char src_str[100];
 241     char grp_str[100];
 242     pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 243     pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 244     zlog_warn("%s: missing RPF interface for upstream (S,G)=(%s,%s)",
 245               __PRETTY_FUNCTION__,
 246               src_str, grp_str);
 247
 248     rpf_addr.s_addr = PIM_NET_INADDR_ANY;
 249     return rpf_addr;
 250   }
 251
 252   rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface,
 253                               up->source_addr, up->group_addr);
 254   if (rpf_ch) {
 255     if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
 256       return rpf_ch->ifassert_winner;
 257     }
 258   }
 259
 260   /* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */
 261
 262   neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
 263                                up->rpf.source_nexthop.mrib_nexthop_addr);
 264   if (neigh)
 265     rpf_addr = neigh->source_addr;
 266   else
 267     rpf_addr.s_addr = PIM_NET_INADDR_ANY;
 268
 269   return rpf_addr;
 270 }