pimd: handling termination device in the MFC

1. special handling of term device in orig mroutes -
The multicast-vxlan termination device ipmr-lo is added to the (*, G)
mroute -
(0.0.0.0, 239.1.1.100)          Iif: uplink-1   Oifs: uplink-1 ipmr-lo
This means that it will be inherited into all the SG entries including the
origination mroute. However we cannot terminate the traffic we originate
so some special handling is needed to exclude the termination device
in the origination entries -
27.0.0.7, 239.1.1.100)          Iif: lo         Oifs: uplink-1

2. special handling of term device on the MLAG pair -
Both MLAG switches pull down BUM-MDT traffic but only one (the DF) can
terminate the traffic. The non-DF must not exclude the termination device
from the MFC to prevent dups to the overlay.
DF -
root@TORC11:~# ip mr |grep "(0.0.0.0, 239.1.1.100)"
(0.0.0.0, 239.1.1.100)           Iif: uplink-1   Oifs: uplink-1 ipmr-lo  State: resolved
root@TORC11:~#
non-DF -
root@TORC12:~# ip mr |grep "(0.0.0.0, 239.1.1.100)"
(0.0.0.0, 239.1.1.100)           Iif: uplink-1   Oifs: uplink-1  State: resolved
root@TORC12:~#

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>

diff --git a/pimd/pim_mroute.c b/pimd/pim_mroute.c
index af75dc63f88fe9c78184861340a5578ddd99ff72..866a19fc9831defe3fed610912782df567ef403e 100644 (file)
--- a/pimd/pim_mroute.c
+++ b/pimd/pim_mroute.c
@@ -42,6 +42,7 @@
 #include "pim_zlookup.h"
 #include "pim_ssm.h"
 #include "pim_sock.h"
+#include "pim_vxlan.h"
 
 static void mroute_read_on(struct pim_instance *pim);
 
@@ -899,6 +900,9 @@ int pim_mroute_add(struct channel_oil *c_oil, const char *name)
        struct pim_interface *pim_reg_ifp;
        int orig_pimreg_ttl;
        bool pimreg_ttl_reset = false;
+       struct pim_interface *vxlan_ifp;
+       int orig_term_ttl;
+       bool orig_term_ttl_reset = false;
 
        pim->mroute_add_last = pim_time_monotonic_sec();
        ++pim->mroute_add_events;
@@ -936,6 +940,23 @@ int pim_mroute_add(struct channel_oil *c_oil, const char *name)
                        /* remember to flip it back after MFC programming */
                        pimreg_ttl_reset = true;
                }
+
+               vxlan_ifp = pim_vxlan_get_term_ifp(pim);
+               /* 1. vxlan termination device must never be added to the
+                * origination mroute (and that can actually happen because
+                * of XG inheritance from the termination mroute) otherwise
+                * traffic will end up looping.
+                * 2. vxlan termination device should be removed from the non-DF
+                * to prevent duplicates to the overlay rxer
+                */
+               if (vxlan_ifp &&
+                       (PIM_UPSTREAM_FLAG_TEST_SRC_VXLAN_ORIG(c_oil->up->flags) ||
+                        PIM_UPSTREAM_FLAG_TEST_MLAG_NON_DF(c_oil->up->flags))) {
+                       orig_term_ttl_reset = true;
+                       orig_term_ttl =
+                               c_oil->oil.mfcc_ttls[vxlan_ifp->mroute_vif_index];
+                       c_oil->oil.mfcc_ttls[vxlan_ifp->mroute_vif_index] = 0;
+               }
        }
 
        /*
@@ -967,6 +988,11 @@ int pim_mroute_add(struct channel_oil *c_oil, const char *name)
        if (pimreg_ttl_reset)
                c_oil->oil.mfcc_ttls[pim_reg_ifp->mroute_vif_index] =
                        orig_pimreg_ttl;
+
+       if (orig_term_ttl_reset)
+               c_oil->oil.mfcc_ttls[vxlan_ifp->mroute_vif_index] =
+                       orig_term_ttl;
+
        if (err) {
                zlog_warn(
                        "%s %s: failure: setsockopt(fd=%d,IPPROTO_IP,MRT_ADD_MFC): errno=%d: %s",