session: delete and add application namespace do not create the global session table

When an application namespace is added, we call session_table_is_alloced
to see if we need to allocate a new session table. That check returns true
even if we removed the session table.
The fix is when we delete an application's global session table,
we need to invalidate fib_index_to_table_index.

Fixed test_vcl test script to run two tests back to back.
The 1st test deletes the application namespace at the end.
The 2nd test adds the application namespace in the beginning.

Type: fix
Fixes: 67bae20b05cb46e5f6d19afeaf1f7a52a5309d59

Change-Id: I67f5cc1b726a07659597a9479df011717db08d0a
Signed-off-by: Steven Luong <sluong@cisco.com>

1 files changed, 51 insertions, 1 deletions

diff --git a/src/vnet/session/session_lookup.c b/src/vnet/session/session_lookup.c
index ff6e5818ce5..1e58e5e7806 100644
--- a/src/vnet/session/session_lookup.c
+++ b/src/vnet/session/session_lookup.c
@@ -37,6 +37,8 @@ static session_lookup_main_t sl_main;
  */
 static u32 *fib_index_to_table_index[2];
 
+static u32 *fib_index_to_lock_count[2];
+
 /* 16 octets */
 typedef CLIB_PACKED (struct {
   union
@@ -1392,6 +1394,23 @@ vnet_session_rule_add_del (session_rule_add_del_args_t *args)
   return rv;
 }
 
+static void
+session_lookup_fib_table_lock (u32 fib_index, u32 protocol)
+{
+  fib_table_lock (fib_index, protocol, sl_main.fib_src);
+  vec_validate (fib_index_to_lock_count[protocol], fib_index);
+  fib_index_to_lock_count[protocol][fib_index]++;
+  ASSERT (fib_index_to_lock_count[protocol][fib_index] > 0);
+}
+
+static void
+session_lookup_fib_table_unlock (u32 fib_index, u32 protocol)
+{
+  fib_table_unlock (fib_index, protocol, sl_main.fib_src);
+  ASSERT (fib_index_to_lock_count[protocol][fib_index] > 0);
+  fib_index_to_lock_count[protocol][fib_index]--;
+}
+
 /**
  * Mark (global) tables as pertaining to app ns
  */
@@ -1407,7 +1426,10 @@ session_lookup_set_tables_appns (app_namespace_t * app_ns)
       fib_index = app_namespace_get_fib_index (app_ns, fp);
       st = session_table_get_or_alloc (fp, fib_index);
       if (st)
-	st->appns_index = app_namespace_index (app_ns);
+	{
+	  st->appns_index = app_namespace_index (app_ns);
+	  session_lookup_fib_table_lock (fib_index, fp);
+	}
     }
 }
 
@@ -1859,6 +1881,14 @@ session_lookup_init (void)
 
   clib_spinlock_init (&slm->st_alloc_lock);
 
+  /* We are not contributing any route to the fib. But we allocate a fib source
+   * so that when we lock the fib table, we can view that we have a lock on the
+   * particular fib table in case we wonder why the fib table is not free after
+   * "ip table del"
+   */
+  slm->fib_src = fib_source_allocate (
+    "session lookup", FIB_SOURCE_PRIORITY_LOW, FIB_SOURCE_BH_SIMPLE);
+
   /*
    * Allocate default table and map it to fib_index 0
    */
@@ -1874,6 +1904,26 @@ session_lookup_init (void)
   session_table_init (st, FIB_PROTOCOL_IP6);
 }
 
+void
+session_lookup_table_cleanup (u32 fib_proto, u32 fib_index)
+{
+  session_table_t *st;
+  u32 table_index;
+
+  session_lookup_fib_table_unlock (fib_index, fib_proto);
+  if (fib_index_to_lock_count[fib_proto][fib_index] == 0)
+    {
+      table_index = session_lookup_get_index_for_fib (fib_proto, fib_index);
+      st = session_table_get (table_index);
+      if (st)
+	{
+	  session_table_free (st, fib_proto);
+	  if (vec_len (fib_index_to_table_index[fib_proto]) > fib_index)
+	    fib_index_to_table_index[fib_proto][fib_index] = ~0;
+	}
+    }
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *