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, 18 insertions, 2 deletions

diff --git a/src/vnet/interface_funcs.h b/src/vnet/interface_funcs.h
index 6d404b46098..c0ad81c6d87 100644
--- a/src/vnet/interface_funcs.h
+++ b/src/vnet/interface_funcs.h
@@ -47,7 +47,7 @@ vnet_get_hw_interface (vnet_main_t * vnm, u32 hw_if_index)
 }
 
 always_inline vnet_hw_interface_t *
-vnet_get_hw_interface_safe (vnet_main_t * vnm, u32 hw_if_index)
+vnet_get_hw_interface_or_null (vnet_main_t * vnm, u32 hw_if_index)
 {
   if (!pool_is_free_index (vnm->interface_main.hw_interfaces, hw_if_index))
     return pool_elt_at_index (vnm->interface_main.hw_interfaces, hw_if_index);
@@ -61,7 +61,7 @@ vnet_get_sw_interface (vnet_main_t * vnm, u32 sw_if_index)
 }
 
 always_inline vnet_sw_interface_t *
-vnet_get_sw_interface_safe (vnet_main_t * vnm, u32 sw_if_index)
+vnet_get_sw_interface_or_null (vnet_main_t * vnm, u32 sw_if_index)
 {
   if (!pool_is_free_index (vnm->interface_main.sw_interfaces, sw_if_index))
     return pool_elt_at_index (vnm->interface_main.sw_interfaces, sw_if_index);
@@ -97,6 +97,22 @@ vnet_get_sup_hw_interface (vnet_main_t * vnm, u32 sw_if_index)
   return vnet_get_hw_interface (vnm, sw->hw_if_index);
 }
 
+always_inline vnet_hw_interface_t *
+vnet_get_sup_hw_interface_api_visible_or_null (vnet_main_t * vnm,
+					       u32 sw_if_index)
+{
+  vnet_sw_interface_t *si;
+  if (PREDICT_FALSE (pool_is_free_index (vnm->interface_main.sw_interfaces,
+					 sw_if_index)))
+    return NULL;
+  si = vnet_get_sup_sw_interface (vnm, sw_if_index);
+  if (PREDICT_FALSE (si->flags & VNET_SW_INTERFACE_FLAG_HIDDEN))
+    return NULL;
+  ASSERT ((si->type == VNET_SW_INTERFACE_TYPE_HARDWARE) ||
+	  (si->type == VNET_SW_INTERFACE_TYPE_PIPE));
+  return vnet_get_hw_interface (vnm, si->hw_if_index);
+}
+
 always_inline vnet_hw_interface_class_t *
 vnet_get_hw_interface_class (vnet_main_t * vnm, u32 hw_class_index)
 {