zebra: clean up client routes when client goes away

  * zebra/zebra_rib.c: Add code to clean up routes added by a client
    (as identfied by 'rib type').

  * zebra/zserv.[ch]: Maintain the type of the routes added by a
    client on the 'zserv' structure -- assume that a given client uses
    a single route type for now.

    Clean up routes from a client when the client goes away (in
    zebra_client_close()).

From: Josh Bailey <joshb@google.com>
Signed-off-by: Avneesh Sachdev <avneesh@opensourcerouting.org>
Signed-off-by: David Lamparter <equinox@diac24.net>

1 files changed, 55 insertions, 0 deletions

diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
index 0035eb6e..8da6c84a 100644
--- a/zebra/zebra_rib.c
+++ b/zebra/zebra_rib.c
@@ -2905,6 +2905,61 @@ rib_sweep_route (void)
   rib_sweep_table (vrf_table (AFI_IP6, SAFI_UNICAST, 0));
 }
 
+/* Delete routes learned from a given client.  */
+/* TODO(wsun) May need to split the sweep process into multiple batches,
+ * so that the process won't take too long if the table is large. */
+static void
+rib_sweep_client_table (struct route_table *table, int rib_type)
+{
+  struct route_node *rn;
+  struct rib *rib;
+  struct rib *next;
+  int ret = 0;
+
+  if (table)
+    for (rn = route_top (table); rn; rn = route_next (rn))
+      for (rib = rn->info; rib; rib = next)
+	{
+	  next = rib->next;
+
+	  if (CHECK_FLAG (rib->status, RIB_ENTRY_REMOVED))
+	    continue;
+
+	  if (rib->type == rib_type)
+            if (CHECK_FLAG (rib->flags, ZEBRA_FLAG_SELECTED))
+	      {
+                /* TODO(wsun) Is this mandatory? What about graceful restart/
+                 * non-stop forwarding */
+	        ret = rib_uninstall_kernel (rn, rib);
+	        if (! ret)
+                  rib_delnode (rn, rib);
+                else
+                  zlog_err ("%s: could not delete routes from kernel!",
+                            __func__);
+	      }
+            else
+              {
+                /* Always delete the node. */
+                rib_delnode (rn, rib);
+              }
+	}
+}
+
+/* Sweep all routes learned from a given client from RIB tables.  */
+void
+rib_sweep_client_route (struct zserv *client)
+{
+  assert(client);
+  int route_type = client->route_type;
+  if (route_type != ZEBRA_ROUTE_MAX)
+    {
+      zlog_debug ("%s: Removing existing routes from client type %d",
+                  __func__, route_type);
+      rib_sweep_client_table (vrf_table (AFI_IP, SAFI_UNICAST, 0), route_type);
+      rib_sweep_client_table (vrf_table (AFI_IP6, SAFI_UNICAST, 0), route_type);
+    }
+}
+
 /* Close RIB and clean up kernel routes. */
 static void
 rib_close_table (struct route_table *table)