api: vat2 and json autogeneration for api messages

VAT2: A completely auto-generated replacement of VAT.
Reads input message in JSON from stdin and outputs received messages in JSON.

A VAT2 plugin is automatically built for a .api file.
There no longer a need for a separate _test.c.

Example:
vat2 show_version {}
{
        "_msgname":     "show_version_reply",
        "retval":       0,
        "program":      "vpe",
        "version":      "21.01-rc0~411-gf6eb348a6",
        "build_date":   "2020-11-19T09:49:25",
        "build_directory":      "/vpp/autogen3"
}

vat2 sw_interface_dump '{"sw_if_index": -1,
                         "name_filter_valid": 0,
                         "name_filter": ""}'
[{
                "_msgname":     "sw_interface_details",
                "sw_if_index":  0,
                "sup_sw_if_index":      0,
                "l2_address":   "00:00:00:00:00:00",
                "flags":        "Invalid ENUM",
                "type": "IF_API_TYPE_HARDWARE",
                "link_duplex":  "LINK_DUPLEX_API_UNKNOWN",
                "link_speed":   0,
                "link_mtu":     0,
                "mtu":  [0, 0, 0, 0],
                "sub_id":       0,
                "sub_number_of_tags":   0,
                "sub_outer_vlan_id":    0,
                "sub_inner_vlan_id":    0,
                "sub_if_flags": "Invalid ENUM",
                "vtr_op":       0,
                "vtr_push_dot1q":       0,
                "vtr_tag1":     0,
                "vtr_tag2":     0,
                "outer_tag":    0,
                "b_dmac":       "00:00:00:00:00:00",
                "b_smac":       "00:00:00:00:00:00",
                "b_vlanid":     0,
                "i_sid":        0,
                "interface_name":       "local0",
                "interface_dev_type":   "local",
                "tag":  ""
        }]

This is the first phase and vat2 is not integrated in packaging yet.

Type: feature
Signed-off-by: Ole Troan <ot@cisco.com>
Change-Id: Ib45ddeafb180ea7da8c5dc274a9274d7a4edc876
Signed-off-by: Ole Troan <ot@cisco.com>
diff --git a/src/vat2/CMakeLists.txt b/src/vat2/CMakeLists.txt
new file mode 100644
index 0000000..690267c
--- /dev/null
+++ b/src/vat2/CMakeLists.txt
@@ -0,0 +1,43 @@
+# Copyright (c) 2020 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.
+
+##############################################################################
+# vat2
+##############################################################################
+add_vpp_executable(vat2 ENABLE_EXPORTS NO_INSTALL
+  SOURCES
+  main.c
+  plugin.c
+  jsonconvert.c
+
+  DEPENDS api_headers
+
+  LINK_LIBRARIES
+  vlibmemoryclient
+  svm
+  vppinfra
+  vppapiclient
+  Threads::Threads
+  rt m dl crypto
+)
+
+##############################################################################
+# vat2 headers
+##############################################################################
+install(
+  FILES
+  jsonconvert.h
+  vat2_helpers.h
+  DESTINATION include/vat2
+  COMPONENT vpp-dev
+)