api: binary api cleanup

Multiple API message handlers call vnet_get_sup_hw_interface(...)
without checking the inbound sw_if_index. This can cause a
pool_elt_at_index ASSERT in a debug image, and major disorder in a
production image.

Given that a number of places are coded as follows, add an
"api_visible_or_null" variant of vnet_get_sup_hw_interface, which
returns NULL given an invalid sw_if_index, or a hidden sw interface:

-  hw = vnet_get_sup_hw_interface (vnm, sw_if_index);
+  hw = vnet_get_sup_hw_interface_api_visible_or_null (vnm, sw_if_index);
   if (hw == NULL || memif_device_class.index != hw->dev_class_index)
     return clib_error_return (0, "not a memif interface");

Rename two existing xxx_safe functions -> xxx_or_null to make it
obvious what they return.

Type: fix

Change-Id: I29996e8d0768fd9e0c5495bd91ff8bedcf2c5697
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/vnet/devices/tap/tap.c b/src/vnet/devices/tap/tap.c
index c090bedbd7f..974a4175fa6 100644
--- a/src/vnet/devices/tap/tap.c
+++ b/src/vnet/devices/tap/tap.c
@@ -514,7 +514,7 @@ tap_delete_if (vlib_main_t * vm, u32 sw_if_index)
   virtio_if_t *vif;
   vnet_hw_interface_t *hw;
 
-  hw = vnet_get_sup_hw_interface (vnm, sw_if_index);
+  hw = vnet_get_sup_hw_interface_api_visible_or_null (vnm, sw_if_index);
   if (hw == NULL || virtio_device_class.index != hw->dev_class_index)
     return VNET_API_ERROR_INVALID_SW_IF_INDEX;
 
@@ -565,9 +565,11 @@ tap_gso_enable_disable (vlib_main_t * vm, u32 sw_if_index, int enable_disable)
   vnet_main_t *vnm = vnet_get_main ();
   virtio_main_t *mm = &virtio_main;
   virtio_if_t *vif;
-  vnet_hw_interface_t *hw = vnet_get_sup_hw_interface (vnm, sw_if_index);
+  vnet_hw_interface_t *hw;
   clib_error_t *err = 0;
 
+  hw = vnet_get_sup_hw_interface_api_visible_or_null (vnm, sw_if_index);
+
   if (hw == NULL || virtio_device_class.index != hw->dev_class_index)
     return VNET_API_ERROR_INVALID_SW_IF_INDEX;