mdata: buffer metadata change tracker plugin

A handy tool in case you need to know which metadata will be changed
when a packet visits a certain node.

Reflect metadata changes into format functions used by the
vpp-specific wireshark dissector.

Type: feature

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I96fe8a24db4082bb29fe2a33cc522e8616a3a1bb

1 files changed, 66 insertions, 0 deletions

diff --git a/src/plugins/mdata/mdata.h b/src/plugins/mdata/mdata.h
new file mode 100644
index 00000000000..6f38918ec25
--- /dev/null
+++ b/src/plugins/mdata/mdata.h
@@ -0,0 +1,66 @@
+
+/*
+ * mdata.h - Buffer metadata change tracker
+ *
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef __included_mdata_h__
+#define __included_mdata_h__
+
+#include <vnet/vnet.h>
+
+#include <vppinfra/hash.h>
+#include <vppinfra/error.h>
+
+/** @file buffer metadata change tracker definitions
+ */
+
+typedef struct
+{
+  /** Node index, ~0 means no data from this run */
+  u32 node_index;
+  /** buffer metadata, cast to vlib_buffer_t as needed */
+  u8 mdata[128];
+} mdata_t;
+
+typedef struct
+{
+  /** API message ID base */
+  u16 msg_id_base;
+
+  /** Per-thread buffer metadata before calling node fcn */
+  mdata_t **before_per_thread;
+
+  /** Spinlock to protect modified metadata by node */
+  clib_spinlock_t modify_lock;
+
+  /** Modified metadata by node */
+  mdata_t *modifies;
+
+  /* convenience */
+  vlib_main_t *vlib_main;
+  vnet_main_t *vnet_main;
+} mdata_main_t;
+
+extern mdata_main_t mdata_main;
+
+#endif /* __included_mdata_h__ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */