pimd: OIF add with PROTO_PIM is not happening if join rxed in PP state

Dumps while in problem state -
============================
[from "show ip pim state"]
Active Source           Group            RPT  IIF               OIL
1      6.0.0.31         239.1.1.111      n    swp1              swp4( J * )
[from "show ip pim join"]
Interface        Address         Source          Group           State      Uptime   Expire Prune
swp3             6.0.0.22        6.0.0.31        239.1.1.111     JOIN       --:--:-- 03:11  --:--

You can see from the dumps that the pim downstream router has joined on
swp3 but that OIF has not been added to the OIL with flag
PIM_OIF_FLAG_PROTO_PIM. This is because the join was rxed while the
ifchannel was in a prune-pending state.

Relevant logs -
===============
[
PIM: recv_prune: prune (S,G)=(6.0.0.31,239.1.1.111) rpt=1 wc=0 upstream=6.0.0.22 holdtime=210 from 6.0.0.28 on swp3
PIM: pim_upstream_ref(pim_ifchannel_add): upstream (6.0.0.31,239.1.1.111) ref count 3 increment
PIM: pim_upstream_add(pim_ifchannel_add): (6.0.0.31,239.1.1.111), iif 6.0.0.26/0 (swp1) found: 1: ref_count: 3
PIM: pim_ifchannel_add: ifchannel (6.0.0.31,239.1.1.111) is created
PIM: pim_joinprune_recv: SGRpt flag is set, del inherit oif from up (6.0.0.31,239.1.1.111)
PIM: pim_mroute_add(pim_channel_del_oif), vrf default Added Route: (6.0.0.31,239.1.1.111) IIF: swp1, OIFS: swp4
PIM: pim_channel_del_oif(pim_joinprune_recv): (S,G)=(6.0.0.31,239.1.1.111): proto_mask=4 IIF:1 OIF=swp3 vif_index=3
PIM: recv_join: join (S,G)=(6.0.0.31,239.1.1.111) rpt=0 wc=0 upstream=6.0.0.22 holdtime=210 from 6.0.0.28 on swp3
PIM: PIM_IFCHANNEL(swp3): (6.0.0.31,239.1.1.111) is switching from SGRpt(PP) to JOIN
PIM: Sending Request for New Channel Oil Information(6.0.0.31,239.1.1.111) VIIF 1(default)
]

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

2 files changed, 27 insertions, 28 deletions

diff --git a/pimd/pim_ifchannel.c b/pimd/pim_ifchannel.c
index d091505837..ca8f061681 100644
--- a/pimd/pim_ifchannel.c
+++ b/pimd/pim_ifchannel.c
@@ -781,6 +781,28 @@ static int nonlocal_upstream(int is_join, struct interface *recv_ifp,
 	return 1; /* non-local */
 }
 
+static void pim_ifchannel_ifjoin_handler(struct pim_ifchannel *ch,
+		struct pim_interface *pim_ifp)
+{
+	pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch,
+			PIM_IFJOIN_JOIN);
+	PIM_IF_FLAG_UNSET_S_G_RPT(ch->flags);
+	/* check if the interface qualifies as an immediate
+	 * OIF
+	 */
+	if (pim_upstream_evaluate_join_desired_interface(
+				ch->upstream, ch,
+				NULL /*starch*/)) {
+		pim_channel_add_oif(ch->upstream->channel_oil,
+				ch->interface,
+				PIM_OIF_FLAG_PROTO_PIM,
+				__func__);
+		pim_upstream_update_join_desired(pim_ifp->pim,
+				ch->upstream);
+	}
+}
+
+
 void pim_ifchannel_join_add(struct interface *ifp, struct in_addr neigh_addr,
 			    struct in_addr upstream, struct prefix_sg *sg,
 			    uint8_t source_flags, uint16_t holdtime)
@@ -888,30 +910,8 @@ void pim_ifchannel_join_add(struct interface *ifp, struct in_addr neigh_addr,
 		if (source_flags & PIM_ENCODE_RPT_BIT)
 			pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch,
 						    PIM_IFJOIN_NOINFO);
-		else {
-			/*
-			 * We have received a S,G join and we are in
-			 * S,G RPT Prune state.  Which means we need
-			 * to transition to Join state and setup
-			 * state as appropriate.
-			 */
-			pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch,
-						    PIM_IFJOIN_JOIN);
-			PIM_IF_FLAG_UNSET_S_G_RPT(ch->flags);
-			/* check if the interface qualifies as an immediate
-			 * OIF
-			 */
-			if (pim_upstream_evaluate_join_desired_interface(
-						ch->upstream, ch,
-						NULL /*starch*/)) {
-				pim_channel_add_oif(ch->upstream->channel_oil,
-						ch->interface,
-						PIM_OIF_FLAG_PROTO_PIM,
-						__func__);
-				pim_upstream_update_join_desired(pim_ifp->pim,
-						ch->upstream);
-			}
-		}
+		else
+			pim_ifchannel_ifjoin_handler(ch, pim_ifp);
 		break;
 	case PIM_IFJOIN_PRUNE_PENDING:
 		THREAD_OFF(ch->t_ifjoin_prune_pending_timer);
@@ -919,9 +919,9 @@ void pim_ifchannel_join_add(struct interface *ifp, struct in_addr neigh_addr,
 			THREAD_OFF(ch->t_ifjoin_expiry_timer);
 			pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch,
 						    PIM_IFJOIN_NOINFO);
-		} else
-			pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch,
-						    PIM_IFJOIN_JOIN);
+		} else {
+			pim_ifchannel_ifjoin_handler(ch, pim_ifp);
+		}
 		break;
 	case PIM_IFJOIN_PRUNE_TMP:
 		break;
diff --git a/pimd/pim_join.c b/pimd/pim_join.c
index 53bfb28228..d63bc83862 100644
--- a/pimd/pim_join.c
+++ b/pimd/pim_join.c
@@ -316,7 +316,6 @@ int pim_joinprune_recv(struct interface *ifp, struct pim_neighbor *neigh,
 			recv_prune(ifp, neigh, msg_holdtime,
 				   msg_upstream_addr.u.prefix4, &sg,
 				   msg_source_flags);
-
 			/*
 			 * So if we are receiving a S,G,RPT prune
 			 * before we have any data for that S,G