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_instance.h"
  26 #include "pim_iface.h"
  27 #include "pim_upstream.h"
  28 #include "pim_oil.h"
  29 #include "pim_nht.h"
  30
  31 static struct channel_oil *
  32 tib_sg_oil_setup(struct pim_instance *pim, pim_sgaddr sg, struct interface *oif)
  33 {
  34         struct pim_interface *pim_oif = oif->info;
  35         int input_iface_vif_index = 0;
  36         pim_addr vif_source;
  37         struct prefix grp;
  38         struct pim_nexthop nexthop;
  39         struct pim_upstream *up = NULL;
  40
  41         if (!pim_rp_set_upstream_addr(pim, &vif_source, sg.src, sg.grp)) {
  42                 /* no PIM RP - create a dummy channel oil */
  43                 return pim_channel_oil_add(pim, &sg, __func__);
  44         }
  45
  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                 (void)pim_ecmp_nexthop_lookup(pim, &nexthop, vif_source, &grp,
  53                                               0);
  54                 if (nexthop.interface)
  55                         input_iface_vif_index = pim_if_find_vifindex_by_ifindex(
  56                                 pim, nexthop.interface->ifindex);
  57         } else
  58                 input_iface_vif_index =
  59                         pim_ecmp_fib_lookup_if_vif_index(pim, vif_source, &grp);
  60
  61         if (PIM_DEBUG_ZEBRA)
  62                 zlog_debug("%s: NHT %pSG vif_source %pPAs vif_index:%d",
  63                            __func__, &sg, &vif_source, input_iface_vif_index);
  64
  65         if (input_iface_vif_index < 1) {
  66                 if (PIM_DEBUG_GM_TRACE)
  67                         zlog_debug(
  68                                 "%s %s: could not find input interface for %pSG",
  69                                 __FILE__, __func__, &sg);
  70
  71                 return pim_channel_oil_add(pim, &sg, __func__);
  72         }
  73
  74         /*
  75          * Protect IGMP against adding looped MFC entries created by both
  76          * source and receiver attached to the same interface. See TODO T22.
  77          * Block only when the intf is non DR DR must create upstream.
  78          */
  79         if ((input_iface_vif_index == pim_oif->mroute_vif_index) &&
  80             !(PIM_I_am_DR(pim_oif))) {
  81                 /* ignore request for looped MFC entry */
  82                 if (PIM_DEBUG_GM_TRACE)
  83                         zlog_debug(
  84                                 "%s: ignoring request for looped MFC entry (S,G)=%pSG: oif=%s vif_index=%d",
  85                                 __func__, &sg, oif->name,
  86                                 input_iface_vif_index);
  87
  88                 return NULL;
  89         }
  90
  91         return pim_channel_oil_add(pim, &sg, __func__);
  92 }
  93
  94 bool tib_sg_gm_join(struct pim_instance *pim, pim_sgaddr sg,
  95                     struct interface *oif, struct channel_oil **oilp)
  96 {
  97         struct pim_interface *pim_oif = oif->info;
  98
  99         if (!pim_oif) {
 100                 if (PIM_DEBUG_GM_TRACE)
 101                         zlog_debug("%s: multicast not enabled on oif=%s?",
 102                                    __func__, oif->name);
 103                 return false;
 104         }
 105
 106         if (!*oilp)
 107                 *oilp = tib_sg_oil_setup(pim, sg, oif);
 108         if (!*oilp)
 109                 return false;
 110
 111         if (PIM_I_am_DR(pim_oif) || PIM_I_am_DualActive(pim_oif)) {
 112                 int result;
 113
 114                 result = pim_channel_add_oif(*oilp, oif, PIM_OIF_FLAG_PROTO_GM,
 115                                              __func__);
 116                 if (result) {
 117                         if (PIM_DEBUG_MROUTE)
 118                                 zlog_warn("%s: add_oif() failed with return=%d",
 119                                           __func__, result);
 120                         return false;
 121                 }
 122         } else {
 123                 if (PIM_DEBUG_GM_TRACE)
 124                         zlog_debug(
 125                                 "%s: %pSG was received on %s interface but we are not DR for that interface",
 126                                 __func__, &sg, oif->name);
 127
 128                 return false;
 129         }
 130         /*
 131           Feed IGMPv3-gathered local membership information into PIM
 132           per-interface (S,G) state.
 133          */
 134         if (!pim_ifchannel_local_membership_add(oif, &sg, false /*is_vxlan*/)) {
 135                 if (PIM_DEBUG_MROUTE)
 136                         zlog_warn(
 137                                 "%s: Failure to add local membership for %pSG",
 138                                 __func__, &sg);
 139
 140                 pim_channel_del_oif(*oilp, oif, PIM_OIF_FLAG_PROTO_GM,
 141                                     __func__);
 142                 return false;
 143         }
 144
 145         return true;
 146 }
 147
 148 void tib_sg_gm_prune(struct pim_instance *pim, pim_sgaddr sg,
 149                      struct interface *oif, struct channel_oil **oilp)
 150 {
 151         int result;
 152
 153         /*
 154          It appears that in certain circumstances that
 155          igmp_source_forward_stop is called when IGMP forwarding
 156          was not enabled in oif_flags for this outgoing interface.
 157          Possibly because of multiple calls. When that happens, we
 158          enter the below if statement and this function returns early
 159          which in turn triggers the calling function to assert.
 160          Making the call to pim_channel_del_oif and ignoring the return code
 161          fixes the issue without ill effect, similar to
 162          pim_forward_stop below.
 163         */
 164         result = pim_channel_del_oif(*oilp, oif, PIM_OIF_FLAG_PROTO_GM,
 165                                      __func__);
 166         if (result) {
 167                 if (PIM_DEBUG_GM_TRACE)
 168                         zlog_debug(
 169                                 "%s: pim_channel_del_oif() failed with return=%d",
 170                                 __func__, result);
 171                 return;
 172         }
 173
 174         /*
 175           Feed IGMPv3-gathered local membership information into PIM
 176           per-interface (S,G) state.
 177          */
 178         pim_ifchannel_local_membership_del(oif, &sg);
 179 }