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>
(cherry picked from commit 3940de36728b768574a3e998389bb90d55f690d1)

3 files changed, 14 insertions, 8 deletions

diff --git a/src/vnet/devices/virtio/cli.c b/src/vnet/devices/virtio/cli.c
index 92e7e93831a..f6cb2b3e6b1 100644
--- a/src/vnet/devices/virtio/cli.c
+++ b/src/vnet/devices/virtio/cli.c
@@ -99,7 +99,7 @@ virtio_pci_delete_command_fn (vlib_main_t * vm, unformat_input_t * input,
     return clib_error_return (0,
 			      "please specify interface name or sw_if_index");
 
-  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 clib_error_return (0, "not a virtio interface");
 
diff --git a/src/vnet/devices/virtio/vhost_user.c b/src/vnet/devices/virtio/vhost_user.c
index f16d015ef5a..a18313b2038 100644
--- a/src/vnet/devices/virtio/vhost_user.c
+++ b/src/vnet/devices/virtio/vhost_user.c
@@ -1250,8 +1250,10 @@ vhost_user_delete_if (vnet_main_t * vnm, vlib_main_t * vm, u32 sw_if_index)
   vnet_hw_interface_t *hwif;
   u16 qid;
 
-  if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
-      hwif->dev_class_index != vhost_user_device_class.index)
+  if (!
+      (hwif =
+       vnet_get_sup_hw_interface_api_visible_or_null (vnm, sw_if_index))
+      || hwif->dev_class_index != vhost_user_device_class.index)
     return VNET_API_ERROR_INVALID_SW_IF_INDEX;
 
   vui = pool_elt_at_index (vum->vhost_user_interfaces, hwif->dev_instance);
@@ -1534,8 +1536,10 @@ vhost_user_modify_if (vnet_main_t * vnm, vlib_main_t * vm,
   vnet_hw_interface_t *hwif;
   uword *if_index;
 
-  if (!(hwif = vnet_get_sup_hw_interface (vnm, sw_if_index)) ||
-      hwif->dev_class_index != vhost_user_device_class.index)
+  if (!
+      (hwif =
+       vnet_get_sup_hw_interface_api_visible_or_null (vnm, sw_if_index))
+      || hwif->dev_class_index != vhost_user_device_class.index)
     return VNET_API_ERROR_INVALID_SW_IF_INDEX;
 
   if (sock_filename == NULL || !(strlen (sock_filename) > 0))
@@ -1658,7 +1662,7 @@ vhost_user_delete_command_fn (vlib_main_t * vm,
 		&sw_if_index))
 	{
 	  vnet_hw_interface_t *hwif =
-	    vnet_get_sup_hw_interface (vnm, sw_if_index);
+	    vnet_get_sup_hw_interface_api_visible_or_null (vnm, sw_if_index);
 	  if (hwif == NULL ||
 	      vhost_user_device_class.index != hwif->dev_class_index)
 	    {
diff --git a/src/vnet/devices/virtio/virtio_api.c b/src/vnet/devices/virtio/virtio_api.c
index ff123ae081c..6e8d34f872e 100644
--- a/src/vnet/devices/virtio/virtio_api.c
+++ b/src/vnet/devices/virtio/virtio_api.c
@@ -97,10 +97,12 @@ vl_api_virtio_pci_delete_t_handler (vl_api_virtio_pci_delete_t * mp)
   vl_api_virtio_pci_delete_reply_t *rmp;
   vl_api_registration_t *reg;
 
-  hw = vnet_get_sup_hw_interface (vnm, htonl (mp->sw_if_index));
+  hw =
+    vnet_get_sup_hw_interface_api_visible_or_null (vnm,
+						   htonl (mp->sw_if_index));
   if (hw == NULL || virtio_device_class.index != hw->dev_class_index)
     {
-      rv = VNET_API_ERROR_INVALID_INTERFACE;
+      rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;
       goto reply;
     }