packetforge: add packetforge for generic flow to extras

Add a new tool packetforge to extras. This tool is to support generic flow.
Packetforge is a library to translate naming or json profile format flow
pattern to the required input of generic flow, i.e. spec and mask. Using
python script flow_create.py, it can add and enable a new flow rule for
an interface via flow VAPI, and can delete an existed flow rule as well.
Command examples are shown below. Json profile examples can be found in
./parsegraph/samples.

Naming format input:
python flow_create.py --add -p "mac()/ipv4(src=1.1.1.1,dst=2.2.2.2)/udp()"
-a "redirect-to-queue 3" -i 1
python flow_create.py --del -i 1 -I 0

Json profile format input:
python flow_create.py -f "./flow_rule_examples/mac_ipv4.json" -i 1

With this command, flow rule can be added or deleted, and the flow
entry can be listed with "show flow entry" command in VPP CLI.

Packetforge is based on a parsegraph. The parsegraph can be built by
users. A Spec can be found in ./parsegraph as guidance. More details
about packetforge are in README file.

Type: feature

Signed-off-by: Ting Xu <ting.xu@intel.com>
Change-Id: Ia9f539741c5dca27ff236f2bcc493c5dd48c0df1

extras/packetforge/Node.py

@@ -0,0 +1,62 @@
+# Copyright (c) 2022 Intel 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.
+
+from NodeField import *
+from NodeAttribute import *
+import json
+
+
+class Node:
+    def __init__(self):
+        self.fields = []
+        self.attributes = []
+        self.attrsDict = {}
+        self.fieldDict = {}
+
+    def Create(jsonfile):
+        f = open(jsonfile, "r", encoding="utf-8")
+        token = json.load(f)
+
+        if token == None:
+            return None
+
+        if token["type"] != "node":
+            return None
+
+        node = Node()
+
+        name = token["name"]
+        if name == None:
+            return None
+
+        node.Name = name
+
+        if token["layout"] == None:
+            return None
+
+        for ft in token["layout"]:
+            field = NodeField.Create(ft)
+            if field == None:
+                return None
+            node.fields.append(field)
+            if not field.IsReserved:
+                node.fieldDict[field.Name] = field
+
+        if "attributes" in token and token["attributes"] != None:
+            for ft in token["attributes"]:
+                attr = NodeAttribute.Create(ft)
+                node.attrsDict[attr.Name] = attr
+                node.attributes.append(attr)
+
+        node.JSON = jsonfile
+        return node