bgpd: Free up changes to attr that the speculative route-map applied

So we have the ability to apply speculative route-maps to
neighbor display to see what the changes would look like
via some show commands.  When we do this we make a
shallow copy of the attr data structure and then pass
it around for applying the routemap.  After we've applied
this route-map and displayed it we really need to clean
up memory that the route-map application applied.

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

1 files changed, 26 insertions, 0 deletions

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 76fc8f968..6ddb2ec8a 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -822,6 +822,32 @@ void bgp_attr_unintern_sub(struct attr *attr)
 #endif
 }
 
+/*
+ * We have some show commands that let you experimentally
+ * apply a route-map.  When we apply the route-map
+ * we are reseting values but not saving them for
+ * posterity via intern'ing( because route-maps don't
+ * do that) but at this point in time we need
+ * to compare the new attr to the old and if the
+ * routemap has changed it we need to, as Snoop Dog says,
+ * Drop it like it's hot
+ */
+void bgp_attr_undup(struct attr *new, struct attr *old)
+{
+	if (new->aspath != old->aspath)
+		aspath_free(new->aspath);
+
+	if (new->community != old->community)
+		community_free(new->community);
+
+	if (new->ecommunity != old->ecommunity)
+		ecommunity_free(&new->ecommunity);
+
+	if (new->lcommunity != old->lcommunity)
+		lcommunity_free(&new->lcommunity);
+
+}
+
 /* Free bgp attribute and aspath. */
 void bgp_attr_unintern(struct attr **pattr)
 {