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>

1 files changed, 89 insertions, 2 deletions

diff --git a/pimd/pim_oil.c b/pimd/pim_oil.c
index 7e88ea4fb..64979ed7e 100644
--- a/pimd/pim_oil.c
+++ b/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));
 }