pimd: Tell ourselves to rescan when we discover an issue

When we have network churn and we have an inherited_olist
notice when we may have a situation where we need
to recalculate the inherited_olist.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

pimd/pim_oil.c

@@ -177,9 +177,12 @@ struct channel_oil *pim_channel_oil_add(struct prefix_sg *sg,
   c_oil = pim_find_channel_oil(sg);
   if (c_oil) {
     if (c_oil->oil.mfcc_parent != input_vif_index)
-      if (PIM_DEBUG_MROUTE)
+      {
-	zlog_debug ("%s: Existing channel oil %s points to %d, modifying to point at %d",
+	c_oil->oil_inherited_rescan = 1;
-		    __PRETTY_FUNCTION__, pim_str_sg_dump(sg), c_oil->oil.mfcc_parent, input_vif_index);
+	if (PIM_DEBUG_MROUTE)
+	  zlog_debug ("%s: Existing channel oil %s points to %d, modifying to point at %d",
+		      __PRETTY_FUNCTION__, pim_str_sg_dump(sg), c_oil->oil.mfcc_parent, input_vif_index);
+      }
     c_oil->oil.mfcc_parent = input_vif_index;
     ++c_oil->oil_ref_count;
     return c_oil;
@@ -315,6 +318,7 @@ int pim_channel_add_oif(struct channel_oil *channel_oil,
     TODO T22.
   */
   if (pim_ifp->mroute_vif_index == channel_oil->oil.mfcc_parent) {
+    channel_oil->oil_inherited_rescan = 1;
     if (PIM_DEBUG_MROUTE)
       {
 	char group_str[INET_ADDRSTRLEN];

pimd/pim_oil.h

@@ -71,6 +71,7 @@ struct channel_counts
 struct channel_oil {
   struct mfcctl oil;
   int           installed;
+  int           oil_inherited_rescan;
   int           oil_size;
   int           oil_ref_count;
   time_t        oif_creation[MAXVIFS];

pimd/pim_upstream.c

@@ -1268,24 +1268,8 @@ pim_upstream_start_register_stop_timer (struct pim_upstream *up, int null_regist
 		   up, time);
 }
 
-/*
- * For a given upstream, determine the inherited_olist
- * and apply it.
- *
- * inherited_olist(S,G,rpt) =
- *           ( joins(*,*,RP(G)) (+) joins(*,G) (-) prunes(S,G,rpt) )
- *      (+) ( pim_include(*,G) (-) pim_exclude(S,G))
- *      (-) ( lost_assert(*,G) (+) lost_assert(S,G,rpt) )
- *
- *  inherited_olist(S,G) =
- *      inherited_olist(S,G,rpt) (+)
- *      joins(S,G) (+) pim_include(S,G) (-) lost_assert(S,G)
- *
- * return 1 if there are any output interfaces
- * return 0 if there are not any output interfaces
- */
 int
-pim_upstream_inherited_olist (struct pim_upstream *up)
+pim_upstream_inherited_olist_decide (struct pim_upstream *up)
 {
   struct pim_interface *pim_ifp;
   struct listnode *chnextnode;
@@ -1310,6 +1294,30 @@ pim_upstream_inherited_olist (struct pim_upstream *up)
 	}
     }
 
+  return output_intf;
+}
+
+/*
+ * For a given upstream, determine the inherited_olist
+ * and apply it.
+ *
+ * inherited_olist(S,G,rpt) =
+ *           ( joins(*,*,RP(G)) (+) joins(*,G) (-) prunes(S,G,rpt) )
+ *      (+) ( pim_include(*,G) (-) pim_exclude(S,G))
+ *      (-) ( lost_assert(*,G) (+) lost_assert(S,G,rpt) )
+ *
+ *  inherited_olist(S,G) =
+ *      inherited_olist(S,G,rpt) (+)
+ *      joins(S,G) (+) pim_include(S,G) (-) lost_assert(S,G)
+ *
+ * return 1 if there are any output interfaces
+ * return 0 if there are not any output interfaces
+ */
+int
+pim_upstream_inherited_olist (struct pim_upstream *up)
+{
+  int output_intf =  pim_upstream_inherited_olist_decide (up);
+
   /*
    * If we have output_intf switch state to Join and work like normal
    * If we don't have an output_intf that means we are probably a

pimd/pim_upstream.h

@@ -162,6 +162,7 @@ void pim_upstream_switch (struct pim_upstream *up, enum pim_upstream_state new_s
 
 const char *pim_upstream_state2str (enum pim_upstream_state join_state);
 
+int pim_upstream_inherited_olist_decide (struct pim_upstream *up);
 int pim_upstream_inherited_olist (struct pim_upstream *up);
 int pim_upstream_empty_inherited_olist (struct pim_upstream *up);
 

pimd/pim_zebra.c

@@ -371,15 +371,25 @@ static void scan_upstream_rpf_cache()
       continue;
 
     if (rpf_result == PIM_RPF_CHANGED) {
-      
+
+      /*
+       * We have detected a case where we might need to rescan
+       * the inherited o_list so do it.
+       */
+      if (up->channel_oil->oil_inherited_rescan)
+	{
+	  pim_upstream_inherited_olist_decide (up);
+	  up->channel_oil->oil_inherited_rescan = 0;
+	}
+
       if (up->join_state == PIM_UPSTREAM_JOINED) {
 	/*
          * If we come up real fast we can be here
 	 * where the mroute has not been installed
 	 * so install it.
 	 */
-	if (up->channel_oil && !up->channel_oil->installed)
+	if (!up->channel_oil->installed)
-          pim_mroute_add (up->channel_oil, __PRETTY_FUNCTION__);
+	  pim_mroute_add (up->channel_oil, __PRETTY_FUNCTION__);
 
 	/*
 	  RFC 4601: 4.5.7.  Sending (S,G) Join/Prune Messages