From e711cd3cece039d91a59834e6a9396f878b99c56 Mon Sep 17 00:00:00 2001
From: Donald Sharp <sharpd@cumulusnetworks.com>
Date: Fri, 10 Mar 2017 10:26:00 -0500
Subject: [PATCH] pimd: Carefully Reconstruct FHR state when interface bounces

When an interface bounces and we receive a packet before
pim has a chance to fully bring the 'struct pim_usptream'
back up correctly, first check to see if we already have
an associated data structure before creating it again.

This removes a case where both the c_oil and up ref counts
were being incremented and never removed properly.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
---
 pimd/pim_mroute.c   | 30 ++++++++++--------------------
 pimd/pim_upstream.c | 23 +++++++++++++++++++++++
 pimd/pim_upstream.h |  3 +++
 3 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/pimd/pim_mroute.c b/pimd/pim_mroute.c
index a244534ab4..04b6a4c697 100644
--- a/pimd/pim_mroute.c
+++ b/pimd/pim_mroute.c
@@ -118,7 +118,6 @@ pim_mroute_msg_nocache (int fd, struct interface *ifp, const struct igmpmsg *msg
   struct pim_upstream *up;
   struct pim_rpf *rpg;
   struct prefix_sg sg;
-  struct channel_oil *oil;
 
   rpg = RP(msg->im_dst);
   /*
@@ -153,25 +152,17 @@ pim_mroute_msg_nocache (int fd, struct interface *ifp, const struct igmpmsg *msg
   sg.src = msg->im_src;
   sg.grp = msg->im_dst;
 
-  oil = pim_channel_oil_add (&sg, pim_ifp->mroute_vif_index);
-  if (!oil) {
-    if (PIM_DEBUG_MROUTE) {
-      zlog_debug("%s: Failure to add channel oil for %s",
-		 __PRETTY_FUNCTION__,
-		 pim_str_sg_dump (&sg));
-    }
-    return 0;
-  }
-
-  up = pim_upstream_add (&sg, ifp, PIM_UPSTREAM_FLAG_MASK_FHR, __PRETTY_FUNCTION__);
-  if (!up) {
-    if (PIM_DEBUG_MROUTE) {
-      zlog_debug("%s: Failure to add upstream information for %s",
-		 __PRETTY_FUNCTION__,
-		 pim_str_sg_dump (&sg));
+  up = pim_upstream_find_or_add (&sg, ifp, PIM_UPSTREAM_FLAG_MASK_FHR, __PRETTY_FUNCTION__);
+  if (!up)
+    {
+      if (PIM_DEBUG_MROUTE)
+        {
+          zlog_debug("%s: Failure to add upstream information for %s",
+                     __PRETTY_FUNCTION__,
+                     pim_str_sg_dump (&sg));
+        }
+      return 0;
     }
-    return 0;
-  }
 
   /*
    * I moved this debug till after the actual add because
@@ -185,7 +176,6 @@ pim_mroute_msg_nocache (int fd, struct interface *ifp, const struct igmpmsg *msg
   PIM_UPSTREAM_FLAG_SET_SRC_STREAM(up->flags);
   pim_upstream_keep_alive_timer_start (up, qpim_keep_alive_time);
 
-  up->channel_oil = oil;
   up->channel_oil->cc.pktcnt++;
   PIM_UPSTREAM_FLAG_SET_FHR(up->flags);
   pim_channel_add_oif (up->channel_oil, pim_regiface, PIM_OIF_FLAG_PROTO_PIM);
diff --git a/pimd/pim_upstream.c b/pimd/pim_upstream.c
index 183db532ba..b29e71a334 100644
--- a/pimd/pim_upstream.c
+++ b/pimd/pim_upstream.c
@@ -669,6 +669,29 @@ struct pim_upstream *pim_upstream_find(struct prefix_sg *sg)
   return up;
 }
 
+struct pim_upstream *
+pim_upstream_find_or_add(struct prefix_sg *sg,
+                         struct interface *incoming,
+                         int flags, const char *name)
+{
+  struct pim_upstream *up;
+
+  up = pim_upstream_find(sg);
+
+  if (up)
+    {
+      if (!(up->flags & flags))
+        {
+          up->flags |= flags;
+          up->ref_count++;
+        }
+    }
+  else
+    up = pim_upstream_add (sg, incoming, flags, name);
+
+  return up;
+}
+
 static void pim_upstream_ref(struct pim_upstream *up, int flags)
 {
   up->flags |= flags;
diff --git a/pimd/pim_upstream.h b/pimd/pim_upstream.h
index 0bc4c4410a..21c78021e5 100644
--- a/pimd/pim_upstream.h
+++ b/pimd/pim_upstream.h
@@ -129,6 +129,9 @@ struct hash *pim_upstream_hash;
 
 void pim_upstream_free(struct pim_upstream *up);
 struct pim_upstream *pim_upstream_find (struct prefix_sg *sg);
+struct pim_upstream *pim_upstream_find_or_add (struct prefix_sg *sg,
+                                               struct interface *ifp, int flags,
+                                               const char *name);
 struct pim_upstream *pim_upstream_add (struct prefix_sg *sg,
 				       struct interface *ifp, int flags,
 				       const char *name);
-- 
2.39.5