pim, pimv6: Removing upstreams and mroutes when "no ip pim"/"no ipv6 …

…pim" configs applied in receiver connected interface

When the (no ip pim/no ipv6 pim) pim/pimv6 configuration is removed from the receiver-connected interface in LHR,
we observe inconsistent behavior in following scenarios.

1) When there is no pim/pimv6 configuration at the beginning and the traffic is initiated,
no multicast routes are formed, and there is no available upstream
frr# show ip pim upstream
 Iif  Source  Group  State  Uptime  JoinTimer  RSTimer  KATimer  RefCnt

frr# show ip mroute
IP Multicast Routing Table
Flags: S - Sparse, C - Connected, P - Pruned
       R - SGRpt Pruned, F - Register flag, T - SPT-bit set
 Source  Group  Flags  Proto  Input  Output  TTL  Uptime

2) When the traffic is flowing and we remove the pim/pimv6 config in between,
the (*,G) upstream transitions into the NotJ state, yet the mroutes remain intact.

frr# show ip mroute
IP Multicast Routing Table
Flags: S - Sparse, C - Connected, P - Pruned
       R - SGRpt Pruned, F - Register flag, T - SPT-bit set
 Source  Group      Flags  Proto  Input   Output  TTL  Uptime
 *       226.1.1.1  SC     IGMP   ens224  pimreg  1    00:00:56
                           IGMP           ens192  1

frr# show ip pim upstream
 Iif     Source  Group      State  Uptime    JoinTimer  RSTimer   KATimer   RefCnt
 ens224  *       226.1.1.1  NotJ   00:00:13  00:00:55   --:--:--  --:--:--  1

Hence, to make the behaviour consistent, we remove both the upstream entries for (*,G)
and the corresponding mroutes using the 'pim_igmp_if_reset' API call when dealing with the receiver-connected interface.
The 'pim_ifchannel_local_membership_del' is returned when no ip pim/pimv6 config is applied due to 'pim_ifp->pim_enable' check.
Therefore, removing this check in order to proceed with the deletion when the pim/pimv6 configurations are removed

Signed-off-by: Sai Gomathi N <[email protected]>

pimd/pim6_mld.c

@@ -2151,6 +2151,15 @@ static void gm_start(struct interface *ifp)
 	}
 }
 
+void pim_gm_if_reset(struct interface *ifp)
+{
+	struct pim_interface *pim_ifp = ifp->info;
+	struct gm_if *gm_ifp = pim_ifp->mld;
+
+	if (gm_ifp)
+		gm_group_delete(gm_ifp);
+}
+
 void gm_group_delete(struct gm_if *gm_ifp)
 {
 	struct gm_sg *sg;

pimd/pim6_mld.h

@@ -357,6 +357,7 @@ struct gm_if {
 #if PIM_IPV == 6
 extern void gm_ifp_update(struct interface *ifp);
 extern void gm_ifp_teardown(struct interface *ifp);
+extern void pim_gm_if_reset(struct interface *ifp);
 extern void gm_group_delete(struct gm_if *gm_ifp);
 #else
 static inline void gm_ifp_update(struct interface *ifp)

pimd/pim_ifchannel.c

@@ -1232,8 +1232,6 @@ void pim_ifchannel_local_membership_del(struct interface *ifp, pim_sgaddr *sg)
 	pim_ifp = ifp->info;
 	if (!pim_ifp)
 		return;
-	if (!pim_ifp->pim_enable)
-		return;
 
 	orig = ch = pim_ifchannel_find(ifp, sg);
 	if (!ch)

pimd/pim_pim.c

@@ -29,6 +29,7 @@
 #include "pim_register.h"
 #include "pim_errors.h"
 #include "pim_bsm.h"
+#include "pim6_mld.h"
 #include <lib/lib_errors.h>
 
 static void on_pim_hello_send(struct event *t);
@@ -102,6 +103,8 @@ static void sock_close(struct interface *ifp)
 
 void pim_sock_delete(struct interface *ifp, const char *delete_message)
 {
+	struct pim_interface *pim_ifp = ifp->info;
+
 	zlog_info("PIM INTERFACE DOWN: on interface %s: %s", ifp->name,
 		  delete_message);
 
@@ -124,6 +127,9 @@ void pim_sock_delete(struct interface *ifp, const char *delete_message)
 	pim_neighbor_delete_all(ifp, delete_message);
 
 	sock_close(ifp);
+
+	if (pim_ifp->gm_enable)
+		pim_gm_if_reset(ifp);
 }
 
 /* For now check dst address for hello, assrt and join/prune is all pim rtr */