pimd/pim_tib.c

   1 /*
   2  * TIB (Tree Information Base) - just PIM <> IGMP/MLD glue for now
   3  * Copyright (C) 2022  David Lamparter for NetDEF, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; either version 2 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * 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 "pim_tib.h"
  23
  24 #include "pimd.h"
  25 #include "pim_iface.h"
  26 #include "pim_upstream.h"
  27 #include "pim_oil.h"
  28 #include "pim_nht.h"
  29
  30 static struct channel_oil *
  31 tib_sg_oil_setup(struct pim_instance *pim, pim_sgaddr sg, struct interface *oif)
  32 {
  33         struct pim_interface *pim_oif = oif->info;
  34         int input_iface_vif_index = 0;
  35         pim_addr vif_source;
  36         struct prefix src, grp;
  37         struct pim_nexthop nexthop;
  38         struct pim_upstream *up = NULL;
  39
  40         if (!pim_rp_set_upstream_addr(pim, &vif_source, sg.src, sg.grp)) {
  41                 /* no PIM RP - create a dummy channel oil */
  42                 return pim_channel_oil_add(pim, &sg, __func__);
  43         }
  44
  45         pim_addr_to_prefix(&src, vif_source); // RP or Src addr
  46         pim_addr_to_prefix(&grp, sg.grp);
  47
  48         up = pim_upstream_find(pim, &sg);
  49         if (up) {
  50                 memcpy(&nexthop, &up->rpf.source_nexthop,
  51                        sizeof(struct pim_nexthop));
  52                 pim_ecmp_nexthop_lookup(pim, &nexthop, &src, &grp, 0);
  53                 if (nexthop.interface)
  54                         input_iface_vif_index = pim_if_find_vifindex_by_ifindex(
  55                                 pim, nexthop.interface->ifindex);
  56         } else
  57                 input_iface_vif_index =
  58                         pim_ecmp_fib_lookup_if_vif_index(pim, &src, &grp);
  59
  60         if (PIM_DEBUG_ZEBRA)
  61                 zlog_debug("%s: NHT %pSG vif_source %pPAs vif_index:%d",
  62                            __func__, &sg, &vif_source, input_iface_vif_index);
  63
  64         if (input_iface_vif_index < 1) {
  65                 if (PIM_DEBUG_IGMP_TRACE)
  66                         zlog_debug(
  67                                 "%s %s: could not find input interface for %pSG",
  68                                 __FILE__, __func__, &sg);
  69
  70                 return pim_channel_oil_add(pim, &sg, __func__);
  71         }
  72
  73         /*
  74          * Protect IGMP against adding looped MFC entries created by both
  75          * source and receiver attached to the same interface. See TODO T22.
  76          * Block only when the intf is non DR DR must create upstream.
  77          */
  78         if ((input_iface_vif_index == pim_oif->mroute_vif_index) &&
  79             !(PIM_I_am_DR(pim_oif))) {
  80                 /* ignore request for looped MFC entry */
  81                 if (PIM_DEBUG_IGMP_TRACE)
  82                         zlog_debug(
  83                                 "%s: ignoring request for looped MFC entry (S,G)=%pSG: oif=%s vif_index=%d",
  84                                 __func__, &sg, oif->name,
  85                                 input_iface_vif_index);
  86
  87                 return NULL;
  88         }
  89
  90         return pim_channel_oil_add(pim, &sg, __func__);
  91 }
  92
  93 bool tib_sg_gm_join(struct pim_instance *pim, pim_sgaddr sg,
  94                     struct interface *oif, struct channel_oil **oilp)
  95 {
  96         struct pim_interface *pim_oif = oif->info;
  97
  98         if (!pim_oif) {
  99                 if (PIM_DEBUG_IGMP_TRACE)
 100                         zlog_debug("%s: multicast not enabled on oif=%s?",
 101                                    __func__, oif->name);
 102                 return false;
 103         }
 104
 105         if (!*oilp)
 106                 *oilp = tib_sg_oil_setup(pim, sg, oif);
 107         if (!*oilp)
 108                 return false;
 109
 110         if (PIM_I_am_DR(pim_oif) || PIM_I_am_DualActive(pim_oif)) {
 111                 int result;
 112
 113                 result = pim_channel_add_oif(*oilp, oif,
 114                                              PIM_OIF_FLAG_PROTO_IGMP, __func__);
 115                 if (result) {
 116                         if (PIM_DEBUG_MROUTE)
 117                                 zlog_warn("%s: add_oif() failed with return=%d",
 118                                           __func__, result);
 119                         return false;
 120                 }
 121         } else {
 122                 if (PIM_DEBUG_IGMP_TRACE)
 123                         zlog_debug(
 124                                 "%s: %pSG was received on %s interface but we are not DR for that interface",
 125                                 __func__, &sg, oif->name);
 126
 127                 return false;
 128         }
 129         /*
 130           Feed IGMPv3-gathered local membership information into PIM
 131           per-interface (S,G) state.
 132          */
 133         if (!pim_ifchannel_local_membership_add(oif, &sg, false /*is_vxlan*/)) {
 134                 if (PIM_DEBUG_MROUTE)
 135                         zlog_warn(
 136                                 "%s: Failure to add local membership for %pSG",
 137                                 __func__, &sg);
 138
 139                 pim_channel_del_oif(*oilp, oif, PIM_OIF_FLAG_PROTO_IGMP,
 140                                     __func__);
 141                 return false;
 142         }
 143
 144         return true;
 145 }
 146
 147 void tib_sg_gm_prune(struct pim_instance *pim, pim_sgaddr sg,
 148                      struct interface *oif, struct channel_oil **oilp)
 149 {
 150         int result;
 151
 152         /*
 153          It appears that in certain circumstances that
 154          igmp_source_forward_stop is called when IGMP forwarding
 155          was not enabled in oif_flags for this outgoing interface.
 156          Possibly because of multiple calls. When that happens, we
 157          enter the below if statement and this function returns early
 158          which in turn triggers the calling function to assert.
 159          Making the call to pim_channel_del_oif and ignoring the return code
 160          fixes the issue without ill effect, similar to
 161          pim_forward_stop below.
 162         */
 163         result = pim_channel_del_oif(*oilp, oif, PIM_OIF_FLAG_PROTO_IGMP,
 164                                      __func__);
 165         if (result) {
 166                 if (PIM_DEBUG_IGMP_TRACE)
 167                         zlog_debug(
 168                                 "%s: pim_channel_del_oif() failed with return=%d",
 169                                 __func__, result);
 170                 return;
 171         }
 172
 173         /*
 174           Feed IGMPv3-gathered local membership information into PIM
 175           per-interface (S,G) state.
 176          */
 177         pim_ifchannel_local_membership_del(oif, &sg);
 178 }