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   $QuaggaId: $Format:%an, %ai, %h$ $
  21 */
  22
  23 #include <zebra.h>
  24
  25 #include "if.h"
  26
  27 #include "log.h"
  28 #include "prefix.h"
  29 #include "memory.h"
  30
  31 #include "pimd.h"
  32 #include "pim_rpf.h"
  33 #include "pim_pim.h"
  34 #include "pim_str.h"
  35 #include "pim_iface.h"
  36 #include "pim_zlookup.h"
  37 #include "pim_ifchannel.h"
  38
  39 static struct in_addr pim_rpf_find_rpf_addr(struct pim_upstream *up);
  40
  41 int pim_nexthop_lookup(struct pim_nexthop *nexthop,
  42                        struct in_addr addr, struct interface *incoming)
  43 {
  44   struct pim_zlookup_nexthop nexthop_tab[PIM_NEXTHOP_IFINDEX_TAB_SIZE];
  45   int num_ifindex;
  46   struct interface *ifp;
  47   int first_ifindex;
  48
  49   memset (nexthop_tab, 0, sizeof (struct pim_zlookup_nexthop) * PIM_NEXTHOP_IFINDEX_TAB_SIZE);
  50
  51   if (!incoming)
  52     {
  53       num_ifindex = zclient_lookup_nexthop(qpim_zclient_lookup, nexthop_tab,
  54                                            PIM_NEXTHOP_IFINDEX_TAB_SIZE,
  55                                            addr, PIM_NEXTHOP_LOOKUP_MAX);
  56       if (num_ifindex < 1) {
  57         char addr_str[100];
  58         pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  59         zlog_warn("%s %s: could not find nexthop ifindex for address %s",
  60                   __FILE__, __PRETTY_FUNCTION__,
  61                   addr_str);
  62         return -1;
  63       }
  64
  65       first_ifindex = nexthop_tab[0].ifindex;
  66
  67       if (num_ifindex > 1) {
  68         char addr_str[100];
  69         pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  70         zlog_info("%s %s: FIXME ignoring multiple nexthop ifindex'es num_ifindex=%d for address %s (using only ifindex=%d)",
  71                   __FILE__, __PRETTY_FUNCTION__,
  72                   num_ifindex, addr_str, first_ifindex);
  73         /* debug warning only, do not return */
  74       }
  75
  76       ifp = if_lookup_by_index(first_ifindex);
  77       if (!ifp) {
  78         char addr_str[100];
  79         pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  80         zlog_warn("%s %s: could not find interface for ifindex %d (address %s)",
  81                   __FILE__, __PRETTY_FUNCTION__,
  82                   first_ifindex, addr_str);
  83         return -2;
  84       }
  85     }
  86   else
  87     {
  88       ifp = incoming;
  89       first_ifindex = ifp->ifindex;
  90     }
  91
  92   if (!ifp->info) {
  93     char addr_str[100];
  94     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
  95     zlog_warn("%s: multicast not enabled on input interface %s (ifindex=%d, RPF for source %s)",
  96               __PRETTY_FUNCTION__,
  97               ifp->name, first_ifindex, addr_str);
  98     /* debug warning only, do not return */
  99   }
 100
 101   if (PIM_DEBUG_PIM_TRACE) {
 102     char nexthop_str[100];
 103     char addr_str[100];
 104     pim_inet4_dump("<nexthop?>", nexthop_tab[0].nexthop_addr, nexthop_str, sizeof(nexthop_str));
 105     pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
 106     zlog_debug("%s %s: found nexthop %s for address %s: interface %s ifindex=%d metric=%d pref=%d",
 107                __FILE__, __PRETTY_FUNCTION__,
 108                nexthop_str, addr_str,
 109                ifp->name, first_ifindex,
 110                nexthop_tab[0].route_metric,
 111                nexthop_tab[0].protocol_distance);
 112   }
 113
 114   /* update nextop data */
 115   nexthop->interface              = ifp;
 116   nexthop->mrib_nexthop_addr      = nexthop_tab[0].nexthop_addr;
 117   nexthop->mrib_metric_preference = nexthop_tab[0].protocol_distance;
 118   nexthop->mrib_route_metric      = nexthop_tab[0].route_metric;
 119
 120   return 0;
 121 }
 122
 123 static int nexthop_mismatch(const struct pim_nexthop *nh1,
 124                             const struct pim_nexthop *nh2)
 125 {
 126   return (nh1->interface != nh2->interface)
 127     ||
 128     (nh1->mrib_nexthop_addr.s_addr != nh2->mrib_nexthop_addr.s_addr)
 129     ||
 130     (nh1->mrib_metric_preference != nh2->mrib_metric_preference)
 131     ||
 132     (nh1->mrib_route_metric != nh2->mrib_route_metric);
 133 }
 134
 135 enum pim_rpf_result pim_rpf_update(struct pim_upstream *up,
 136                                    struct in_addr *old_rpf_addr,
 137                                    struct interface *incoming)
 138 {
 139   struct in_addr      save_rpf_addr;
 140   struct pim_nexthop  save_nexthop;
 141   struct pim_rpf     *rpf = &up->rpf;
 142
 143   save_nexthop  = rpf->source_nexthop; /* detect change in pim_nexthop */
 144   save_rpf_addr = rpf->rpf_addr;       /* detect change in RPF'(S,G) */
 145
 146   if (pim_nexthop_lookup(&rpf->source_nexthop,
 147                          up->upstream_addr, incoming)) {
 148     return PIM_RPF_FAILURE;
 149   }
 150
 151   rpf->rpf_addr = pim_rpf_find_rpf_addr(up);
 152   if (PIM_INADDR_IS_ANY(rpf->rpf_addr) && PIM_DEBUG_PIM_EVENTS) {
 153     /* RPF'(S,G) not found */
 154     char src_str[100];
 155     char grp_str[100];
 156     pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 157     pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 158     zlog_debug("%s %s: RPF'(%s,%s) not found: won't send join upstream",
 159                __FILE__, __PRETTY_FUNCTION__,
 160                src_str, grp_str);
 161     /* warning only */
 162   }
 163
 164   /* detect change in pim_nexthop */
 165   if (nexthop_mismatch(&rpf->source_nexthop, &save_nexthop)) {
 166
 167     if (PIM_DEBUG_PIM_EVENTS) {
 168       char src_str[100];
 169       char grp_str[100];
 170       char nhaddr_str[100];
 171       pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 172       pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 173       pim_inet4_dump("<addr?>", rpf->source_nexthop.mrib_nexthop_addr, nhaddr_str, sizeof(nhaddr_str));
 174       zlog_debug("%s %s: (S,G)=(%s,%s) source nexthop now is: interface=%s address=%s pref=%d metric=%d",
 175                  __FILE__, __PRETTY_FUNCTION__,
 176                  src_str, grp_str,
 177                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
 178                  nhaddr_str,
 179                  rpf->source_nexthop.mrib_metric_preference,
 180                  rpf->source_nexthop.mrib_route_metric);
 181     }
 182
 183     pim_upstream_update_join_desired(up);
 184     pim_upstream_update_could_assert(up);
 185     pim_upstream_update_my_assert_metric(up);
 186   }
 187
 188   /* detect change in RPF_interface(S) */
 189   if (save_nexthop.interface != rpf->source_nexthop.interface) {
 190
 191     if (PIM_DEBUG_PIM_EVENTS) {
 192       char src_str[100];
 193       char grp_str[100];
 194       pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 195       pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 196       zlog_debug("%s %s: (S,G)=(%s,%s) RPF_interface(S) changed from %s to %s",
 197                  __FILE__, __PRETTY_FUNCTION__,
 198                  src_str, grp_str,
 199                  save_nexthop.interface ? save_nexthop.interface->name : "<oldif?>",
 200                  rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
 201       /* warning only */
 202     }
 203
 204     pim_upstream_rpf_interface_changed(up, save_nexthop.interface);
 205   }
 206
 207   /* detect change in RPF'(S,G) */
 208   if (save_rpf_addr.s_addr != rpf->rpf_addr.s_addr) {
 209
 210     /* return old rpf to caller ? */
 211     if (old_rpf_addr)
 212       *old_rpf_addr = save_rpf_addr;
 213
 214     return PIM_RPF_CHANGED;
 215   }
 216
 217   return PIM_RPF_OK;
 218 }
 219
 220 /*
 221   RFC 4601: 4.1.6.  State Summarization Macros
 222
 223      neighbor RPF'(S,G) {
 224          if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
 225               return AssertWinner(S, G, RPF_interface(S) )
 226          } else {
 227               return NBR( RPF_interface(S), MRIB.next_hop( S ) )
 228          }
 229      }
 230
 231   RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
 232   packets should be coming and to which joins should be sent on the RP
 233   tree and SPT, respectively.
 234 */
 235 static struct in_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
 236 {
 237   struct pim_ifchannel *rpf_ch;
 238   struct pim_neighbor *neigh;
 239   struct in_addr rpf_addr;
 240
 241   if (!up->rpf.source_nexthop.interface) {
 242     char src_str[100];
 243     char grp_str[100];
 244     pim_inet4_dump("<src?>", up->source_addr, src_str, sizeof(src_str));
 245     pim_inet4_dump("<grp?>", up->group_addr, grp_str, sizeof(grp_str));
 246     zlog_warn("%s: missing RPF interface for upstream (S,G)=(%s,%s)",
 247               __PRETTY_FUNCTION__,
 248               src_str, grp_str);
 249
 250     rpf_addr.s_addr = PIM_NET_INADDR_ANY;
 251     return rpf_addr;
 252   }
 253
 254   rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface,
 255                               up->source_addr, up->group_addr);
 256   if (rpf_ch) {
 257     if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
 258       return rpf_ch->ifassert_winner;
 259     }
 260   }
 261
 262   /* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */
 263
 264   neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
 265                                up->rpf.source_nexthop.mrib_nexthop_addr);
 266   if (neigh)
 267     rpf_addr = neigh->source_addr;
 268   else
 269     rpf_addr.s_addr = PIM_NET_INADDR_ANY;
 270
 271   return rpf_addr;
 272 }