pimd: MUTE flag to suppress traffic forwarding on non-DF

If an mroute loses DF election (with the MLAG peer) it has to stop
forwarding traffic on active-active devices such as ipmr-lo used
for vxlan traffic termination. To acheive that this commit
introduces a concept of OIF muting. That way we can let the PIM and
IGMP state machines play out and silence OIFs after the fact.

Relevant outputs:
=================
1. muted OIFs are displayed with the M flag in "pim state" -
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
root@TORC12:~# net show pim state |grep "27.0.0.13"|grep 100
1         27.0.0.13        239.1.1.100      uplink-1          ipmr-lo(   *M)
root@TORC12:~#
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
2. And supressed altogether in the mroute output -
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
root@TORC12:~# net show mroute |grep "27.0.0.13"|grep 100
27.0.0.13       239.1.1.100     none   uplink-1         none             0    --:--:--
root@TORC12:~#
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

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

pimd/pim_cmd.c

@@ -1988,7 +1988,7 @@ static void pim_show_state(struct pim_instance *pim, struct vty *vty,
 		json = json_object_new_object();
 	} else {
 		vty_out(vty,
-			"Codes: J -> Pim Join, I -> IGMP Report, S -> Source, * -> Inherited from (*,G), V -> VxLAN");
+			"Codes: J -> Pim Join, I -> IGMP Report, S -> Source, * -> Inherited from (*,G), V -> VxLAN, M -> Muted");
 		vty_out(vty,
 			"\nInstalled Source           Group            IIF               OIL\n");
 	}
@@ -2117,25 +2117,7 @@ static void pim_show_state(struct pim_instance *pim, struct vty *vty,
 			} else {
 				if (first_oif) {
 					first_oif = 0;
-					vty_out(vty, "%s(%c%c%c%c)", out_ifname,
+					vty_out(vty, "%s(%c%c%c%c%c)",
-						(c_oil->oif_flags[oif_vif_index]
-						 & PIM_OIF_FLAG_PROTO_IGMP)
-							? 'I'
-							: ' ',
-						(c_oil->oif_flags[oif_vif_index]
-						 & PIM_OIF_FLAG_PROTO_PIM)
-							? 'J'
-							: ' ',
-						(c_oil->oif_flags[oif_vif_index]
-						 & PIM_OIF_FLAG_PROTO_VXLAN)
-							? 'V'
-							: ' ',
-						(c_oil->oif_flags[oif_vif_index]
-						 & PIM_OIF_FLAG_PROTO_STAR)
-							? '*'
-							: ' ');
-				} else
-					vty_out(vty, ", %s(%c%c%c%c)",
 						out_ifname,
 						(c_oil->oif_flags[oif_vif_index]
 						 & PIM_OIF_FLAG_PROTO_IGMP)
@@ -2152,6 +2134,33 @@ static void pim_show_state(struct pim_instance *pim, struct vty *vty,
 						(c_oil->oif_flags[oif_vif_index]
 						 & PIM_OIF_FLAG_PROTO_STAR)
 							? '*'
+							: ' ',
+						(c_oil->oif_flags[oif_vif_index]
+						 & PIM_OIF_FLAG_MUTE)
+							? 'M'
+							: ' ');
+				} else
+					vty_out(vty, ", %s(%c%c%c%c%c)",
+						out_ifname,
+						(c_oil->oif_flags[oif_vif_index]
+						 & PIM_OIF_FLAG_PROTO_IGMP)
+							? 'I'
+							: ' ',
+						(c_oil->oif_flags[oif_vif_index]
+						 & PIM_OIF_FLAG_PROTO_PIM)
+							? 'J'
+							: ' ',
+						(c_oil->oif_flags[oif_vif_index]
+						 & PIM_OIF_FLAG_PROTO_VXLAN)
+							? 'V'
+							: ' ',
+						(c_oil->oif_flags[oif_vif_index]
+						 & PIM_OIF_FLAG_PROTO_STAR)
+							? '*'
+							: ' ',
+						(c_oil->oif_flags[oif_vif_index]
+						 & PIM_OIF_FLAG_MUTE)
+							? 'M'
 							: ' ');
 			}
 		}
@@ -5292,6 +5301,11 @@ static void show_mroute(struct pim_instance *pim, struct vty *vty,
 			if (ttl < 1)
 				continue;
 
+			/* do not display muted OIFs */
+			if (c_oil->oif_flags[oif_vif_index]
+					& PIM_OIF_FLAG_MUTE)
+				continue;
+
 			ifp_out = pim_if_find_by_vif_index(pim, oif_vif_index);
 			pim_time_uptime(
 				mroute_uptime, sizeof(mroute_uptime),

pimd/pim_oil.c

@@ -31,6 +31,7 @@
 #include "pim_str.h"
 #include "pim_iface.h"
 #include "pim_time.h"
+#include "pim_vxlan.h"
 
 // struct list *pim_channel_oil_list = NULL;
 // struct hash *pim_channel_oil_hash = NULL;
@@ -311,7 +312,8 @@ int pim_channel_del_oif(struct channel_oil *channel_oil, struct interface *oif,
 
 	channel_oil->oif_flags[pim_ifp->mroute_vif_index] &= ~proto_mask;
 
-	if (channel_oil->oif_flags[pim_ifp->mroute_vif_index]) {
+	if (channel_oil->oif_flags[pim_ifp->mroute_vif_index] &
+			PIM_OIF_FLAG_PROTO_ANY) {
 		if (PIM_DEBUG_MROUTE) {
 			char group_str[INET_ADDRSTRLEN];
 			char source_str[INET_ADDRSTRLEN];
@@ -333,6 +335,8 @@ int pim_channel_del_oif(struct channel_oil *channel_oil, struct interface *oif,
 	}
 
 	channel_oil->oil.mfcc_ttls[pim_ifp->mroute_vif_index] = 0;
+	/* clear mute; will be re-evaluated when the OIF becomes valid again */
+	channel_oil->oif_flags[pim_ifp->mroute_vif_index] &= ~PIM_OIF_FLAG_MUTE;
 
 	if (pim_mroute_add(channel_oil, __PRETTY_FUNCTION__)) {
 		if (PIM_DEBUG_MROUTE) {
@@ -373,6 +377,77 @@ int pim_channel_del_oif(struct channel_oil *channel_oil, struct interface *oif,
 }
 
 
+static bool pim_channel_eval_oif_mute(struct channel_oil *c_oil,
+		struct pim_interface *pim_ifp)
+{
+	struct pim_interface *pim_reg_ifp;
+	struct pim_interface *vxlan_ifp;
+	bool do_mute = false;
+	struct pim_instance *pim = c_oil->pim;
+
+	if (!c_oil->up)
+		return do_mute;
+
+	pim_reg_ifp = pim->regiface->info;
+	if (pim_ifp == pim_reg_ifp) {
+		/* suppress pimreg in the OIL if the mroute is not supposed to
+		 * trigger register encapsulated data
+		 */
+		if (PIM_UPSTREAM_FLAG_TEST_NO_PIMREG_DATA(c_oil->up->flags))
+			do_mute = true;
+
+		return do_mute;
+	}
+
+	vxlan_ifp = pim_vxlan_get_term_ifp(pim);
+	if (pim_ifp == vxlan_ifp) {
+		/* 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.
+		 * PS: This check has also been extended to non-orig mroutes
+		 * that have a local SIP as such mroutes can move back and
+		 * forth between orig<=>non-orig type.
+		 * 2. vxlan termination device should be removed from the non-DF
+		 * to prevent duplicates to the overlay rxer
+		 */
+		if (PIM_UPSTREAM_FLAG_TEST_SRC_VXLAN_ORIG(c_oil->up->flags) ||
+			PIM_UPSTREAM_FLAG_TEST_MLAG_NON_DF(c_oil->up->flags) ||
+			pim_vxlan_is_local_sip(c_oil->up))
+			do_mute = true;
+
+		return do_mute;
+	}
+
+	return do_mute;
+}
+
+void pim_channel_update_oif_mute(struct channel_oil *c_oil,
+		struct pim_interface *pim_ifp)
+{
+	bool old_mute;
+	bool new_mute;
+
+	/* If pim_ifp is not a part of the OIL there is nothing to do */
+	if (!c_oil->oil.mfcc_ttls[pim_ifp->mroute_vif_index])
+		return;
+
+	old_mute = !!(c_oil->oif_flags[pim_ifp->mroute_vif_index] &
+			PIM_OIF_FLAG_MUTE);
+	new_mute = pim_channel_eval_oif_mute(c_oil, pim_ifp);
+	if (old_mute == new_mute)
+		return;
+
+	if (new_mute)
+		c_oil->oif_flags[pim_ifp->mroute_vif_index] |=
+			PIM_OIF_FLAG_MUTE;
+	else
+		c_oil->oif_flags[pim_ifp->mroute_vif_index] &=
+			~PIM_OIF_FLAG_MUTE;
+
+	pim_mroute_add(c_oil, __PRETTY_FUNCTION__);
+}
+
 int pim_channel_add_oif(struct channel_oil *channel_oil, struct interface *oif,
 			uint32_t proto_mask, const char *caller)
 {
@@ -517,6 +592,18 @@ int pim_channel_add_oif(struct channel_oil *channel_oil, struct interface *oif,
 	channel_oil->oil.mfcc_ttls[pim_ifp->mroute_vif_index] =
 		PIM_MROUTE_MIN_TTL;
 
+	/* Some OIFs are held in a muted state i.e. the PIM state machine
+	 * decided to include the OIF but additional status check such as
+	 * MLAG DF role prevent it from being activated for traffic
+	 * forwarding.
+	 */
+	if (pim_channel_eval_oif_mute(channel_oil, pim_ifp))
+		channel_oil->oif_flags[pim_ifp->mroute_vif_index] |=
+			PIM_OIF_FLAG_MUTE;
+	else
+		channel_oil->oif_flags[pim_ifp->mroute_vif_index] &=
+			~PIM_OIF_FLAG_MUTE;
+
 	/* channel_oil->oil.mfcc_parent != MAXVIFS indicate this entry is not
 	 * valid to get installed in kernel.
 	 */
@@ -581,5 +668,5 @@ int pim_channel_oil_empty(struct channel_oil *c_oil)
 		inited = 1;
 	}
 
-	return !memcmp(c_oil->oif_flags, zero, MAXVIFS * sizeof(uint32_t));
+	return !memcmp(c_oil->oil.mfcc_ttls, zero, MAXVIFS * sizeof(uint32_t));
 }

pimd/pim_oil.h

@@ -21,6 +21,7 @@
 #define PIM_OIL_H
 
 #include "pim_mroute.h"
+#include "pim_iface.h"
 
 /*
  * Where did we get this (S,G) from?
@@ -38,6 +39,8 @@
 	(PIM_OIF_FLAG_PROTO_IGMP | PIM_OIF_FLAG_PROTO_PIM      \
 	 | PIM_OIF_FLAG_PROTO_STAR | PIM_OIF_FLAG_PROTO_VXLAN)
 
+/* OIF is present in the OIL but must not be used for forwarding traffic */
+#define PIM_OIF_FLAG_MUTE         (1 << 4)
 /*
  * We need a pimreg vif id from the kernel.
  * Since ifindex == vif id for most cases and the number
@@ -127,4 +130,7 @@ int pim_channel_del_oif(struct channel_oil *c_oil, struct interface *oif,
 int pim_channel_oil_empty(struct channel_oil *c_oil);
 
 char *pim_channel_oil_dump(struct channel_oil *c_oil, char *buf, size_t size);
+
+void pim_channel_update_oif_mute(struct channel_oil *c_oil,
+		struct pim_interface *pim_ifp);
 #endif /* PIM_OIL_H */

pimd/pim_vxlan.c

@@ -292,6 +292,7 @@ static void pim_vxlan_orig_mr_up_add(struct pim_vxlan_sg *vxlan_sg)
 	struct pim_upstream *up;
 	int flags = 0;
 	struct prefix nht_p;
+	struct pim_instance *pim = vxlan_sg->pim;
 
 	if (vxlan_sg->up) {
 		/* nothing to do */
@@ -349,6 +350,10 @@ static void pim_vxlan_orig_mr_up_add(struct pim_vxlan_sg *vxlan_sg)
 		pim_upstream_ref(up, flags, __PRETTY_FUNCTION__);
 		vxlan_sg->up = up;
 		pim_vxlan_orig_mr_up_iif_update(vxlan_sg);
+		/* mute pimreg on origination mroutes */
+		if (pim->regiface)
+			pim_channel_update_oif_mute(up->channel_oil,
+					pim->regiface->info);
 	} else {
 		up = pim_upstream_add(vxlan_sg->pim, &vxlan_sg->sg,
 				vxlan_sg->iif, flags,