l2: crash on l2_input_is_xconnect

Running vpp without any interface configured and then invoking the
binary-api l2_xconnect_dump causes vpp to crash in l2_input_is_xconnect due
to l2input_main.configs has no memory allocated to it, not even for the local
interface which exists all the times.

The reason that l2input_main.configs has no memory allocated to it was due to
gerrit patch 29232 which took out a line in l2input_init

  /* Create the config vector */
  vec_validate (mp->configs, 100);

The fix is to iterate through l2input_main.configs for each interface in
l2 to call l2_input_is_xconnect when dumping l2_xconnect interfaces.

Type: fix
Fixes: gerrit 29232

Signed-off-by: Steven Luong <sluong@cisco.com>
Change-Id: I8d9cba4b7eba4c2e0c60887c4fd57d5ec3b06d3b

1 files changed, 8 insertions, 10 deletions

diff --git a/src/vnet/l2/l2_api.c b/src/vnet/l2/l2_api.c
index 85e9c31e2fb..70d6eeff424 100644
--- a/src/vnet/l2/l2_api.c
+++ b/src/vnet/l2/l2_api.c
@@ -103,10 +103,8 @@ static void
 vl_api_l2_xconnect_dump_t_handler (vl_api_l2_xconnect_dump_t * mp)
 {
   vl_api_registration_t *reg;
-  vnet_main_t *vnm = vnet_get_main ();
-  vnet_interface_main_t *im = &vnm->interface_main;
   l2input_main_t *l2im = &l2input_main;
-  vnet_sw_interface_t *swif;
+  u32 sw_if_index;
   l2_input_config_t *config;
 
   reg = vl_api_client_index_to_registration (mp->client_index);
@@ -114,13 +112,13 @@ vl_api_l2_xconnect_dump_t_handler (vl_api_l2_xconnect_dump_t * mp)
     return;
 
   /* *INDENT-OFF* */
-  pool_foreach (swif, im->sw_interfaces)
-   {
-    config = vec_elt_at_index (l2im->configs, swif->sw_if_index);
-    if (l2_input_is_xconnect(config))
-      send_l2_xconnect_details (reg, mp->context, swif->sw_if_index,
-                                config->output_sw_if_index);
-  }
+  vec_foreach_index (sw_if_index, l2im->configs)
+    {
+      config = vec_elt_at_index (l2im->configs, sw_if_index);
+      if (l2_input_is_xconnect (config))
+	send_l2_xconnect_details (reg, mp->context, sw_if_index,
+				  config->output_sw_if_index);
+    }
   /* *INDENT-ON* */
 }