Add a 64-byte interface "tag" for vhost and tap interfaces

This patch should dispose of spurious objections around interface tag
requirements, currently in use as excuses not to support the vpp ML2
plugin.

Add "u8 tag[64];" to the sw_interface_details message sent by vpp to
control-plane clients. Add u8 tag[64] to the create_vhost_user_if and
tap_connect APIs.

Added debug CLI to set/show/clear the interface tag on any vnet sw
interface. Added the sw_interface_tag_add_del API to set/clear
tags on any vnet sw interface.

There can be no expectation of "tag atomicity" with respect to
physical hardware. Vpp discovers devices before establishing a
control-plane connection.

This patch upload verifies using the csit oper-161128 branch

Change-Id: If8520119e7a586c5ccf0fdda82484ac205622855
Signed-off-by: Dave Barach <dave@barachs.net>

4 files changed, 107 insertions, 1 deletions

diff --git a/vnet/vnet/interface.c b/vnet/vnet/interface.c
index e552733e58b..6e3d7f291b7 100644
--- a/vnet/vnet/interface.c
+++ b/vnet/vnet/interface.c
@@ -1202,6 +1202,7 @@ vnet_interface_init (vlib_main_t * vm)
 
     return error;
   }
+  vnm->interface_tag_by_sw_if_index = hash_create (0, sizeof (uword));
 }
 
 VLIB_INIT_FUNCTION (vnet_interface_init);
diff --git a/vnet/vnet/interface_cli.c b/vnet/vnet/interface_cli.c
index 1c15eb18028..7dbee867ded 100644
--- a/vnet/vnet/interface_cli.c
+++ b/vnet/vnet/interface_cli.c
@@ -228,6 +228,7 @@ show_sw_interfaces (vlib_main_t * vm,
   u32 sw_if_index = ~(u32) 0;
   u8 show_addresses = 0;
   u8 show_features = 0;
+  u8 show_tag = 0;
 
   while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
     {
@@ -242,6 +243,8 @@ show_sw_interfaces (vlib_main_t * vm,
 	show_addresses = 1;
       else if (unformat (input, "features") || unformat (input, "feat"))
 	show_features = 1;
+      else if (unformat (input, "tag"))
+	show_tag = 1;
       else
 	{
 	  error = clib_error_return (0, "unknown input `%U'",
@@ -250,14 +253,26 @@ show_sw_interfaces (vlib_main_t * vm,
 	}
     }
 
-  if (show_features)
+  if (show_features || show_tag)
     {
       if (sw_if_index == ~(u32) 0)
 	return clib_error_return (0, "Interface not specified...");
+    }
 
+  if (show_features)
+    {
       vnet_interface_features_show (vm, sw_if_index);
       return 0;
     }
+  if (show_tag)
+    {
+      u8 *tag;
+      tag = vnet_get_sw_interface_tag (vnm, sw_if_index);
+      vlib_cli_output (vm, "%U: %s",
+		       format_vnet_sw_if_index_name, vnm, sw_if_index,
+		       tag ? (char *) tag : "(none)");
+      return 0;
+    }
 
   if (!show_addresses)
     vlib_cli_output (vm, "%U\n", format_vnet_sw_interface, vnm, 0);
@@ -1091,6 +1106,56 @@ VLIB_CLI_COMMAND (set_interface_mac_address_cmd, static) = {
 };
 /* *INDENT-ON* */
 
+static clib_error_t *
+set_tag (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 sw_if_index = ~0;
+  u8 *tag = 0;
+
+  if (!unformat (input, "%U %s", unformat_vnet_sw_interface,
+		 vnm, &sw_if_index, &tag))
+    return clib_error_return (0, "unknown input `%U'",
+			      format_unformat_error, input);
+
+  vnet_set_sw_interface_tag (vnm, tag, sw_if_index);
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (set_tag_command, static) = {
+  .path = "set interface tag",
+  .short_help = "set interface tag <intfc> <tag>",
+  .function = set_tag,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+clear_tag (vlib_main_t * vm, unformat_input_t * input,
+	   vlib_cli_command_t * cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 sw_if_index = ~0;
+
+  if (!unformat (input, "%U", unformat_vnet_sw_interface, vnm, &sw_if_index))
+    return clib_error_return (0, "unknown input `%U'",
+			      format_unformat_error, input);
+
+  vnet_clear_sw_interface_tag (vnm, sw_if_index);
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (clear_tag_command, static) = {
+  .path = "clear interface tag",
+  .short_help = "clear interface tag <intfc>",
+  .function = clear_tag,
+};
+/* *INDENT-ON* */
+
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/vnet/vnet/interface_funcs.h b/vnet/vnet/interface_funcs.h
index 17c677f07b6..a488599cff0 100644
--- a/vnet/vnet/interface_funcs.h
+++ b/vnet/vnet/interface_funcs.h
@@ -92,6 +92,44 @@ vnet_get_device_class (vnet_main_t * vnm, u32 dev_class_index)
 			   dev_class_index);
 }
 
+static inline u8 *
+vnet_get_sw_interface_tag (vnet_main_t * vnm, u32 sw_if_index)
+{
+  uword *p;
+  p = hash_get (vnm->interface_tag_by_sw_if_index, sw_if_index);
+  if (p)
+    return ((u8 *) p[0]);
+  return 0;
+}
+
+static inline void
+vnet_set_sw_interface_tag (vnet_main_t * vnm, u8 * tag, u32 sw_if_index)
+{
+  uword *p;
+  p = hash_get (vnm->interface_tag_by_sw_if_index, sw_if_index);
+  if (p)
+    {
+      u8 *oldtag = (u8 *) p[0];
+      hash_unset (vnm->interface_tag_by_sw_if_index, sw_if_index);
+      vec_free (oldtag);
+    }
+
+  hash_set (vnm->interface_tag_by_sw_if_index, sw_if_index, tag);
+}
+
+static inline void
+vnet_clear_sw_interface_tag (vnet_main_t * vnm, u32 sw_if_index)
+{
+  uword *p;
+  p = hash_get (vnm->interface_tag_by_sw_if_index, sw_if_index);
+  if (p)
+    {
+      u8 *oldtag = (u8 *) p[0];
+      hash_unset (vnm->interface_tag_by_sw_if_index, sw_if_index);
+      vec_free (oldtag);
+    }
+}
+
 /**
  * Call back walk type for walking SW indices on a HW interface
  */
diff --git a/vnet/vnet/vnet.h b/vnet/vnet/vnet.h
index 36cdddd6ba4..5a8ae858678 100644
--- a/vnet/vnet/vnet.h
+++ b/vnet/vnet/vnet.h
@@ -68,6 +68,8 @@ typedef struct vnet_main_t
     _vnet_interface_function_list_elt_t
     * sw_interface_admin_up_down_functions[VNET_ITF_FUNC_N_PRIO];
 
+  uword *interface_tag_by_sw_if_index;
+
   /*
    * Last "api" error, preserved so we can issue reasonable diagnostics
    * at or near the top of the food chain