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
diff --git a/extras/packetforge/NodeField.py b/extras/packetforge/NodeField.py
new file mode 100644
index 0000000..5788984
--- /dev/null
+++ b/extras/packetforge/NodeField.py
@@ -0,0 +1,86 @@
+# 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.
+
+import ExpressionConverter
+from InputFormat import *
+
+
+class NodeField:
+    def __init__(self):
+        self.DefaultValue = None
+        self.IsReserved = None
+        self.IsReadonly = None
+        self.IsAutoIncrease = None
+        self.IsIncreaseLength = None
+        self.Optional = None
+        self.VariableSize = None
+
+    def Create(token):
+        if token == None:
+            return None
+
+        field = NodeField()
+
+        if token["name"] == None:
+            return None
+        if token["size"] == None:
+            return None
+
+        # name
+        field.Name = token["name"]
+
+        if field.Name == "reserved":
+            field.IsReserved = True
+
+        inputFormat = InputFormat.bytearray
+        res, u16 = ExpressionConverter.ToNum(token["size"])
+
+        # size
+        if res:
+            field.Size = u16
+            if u16 <= 8:
+                inputFormat = InputFormat.u8
+            elif u16 <= 16:
+                inputFormat = InputFormat.u16
+            elif u16 <= 32:
+                inputFormat = InputFormat.u32
+            elif u16 <= 64:
+                inputFormat = InputFormat.u64
+            else:
+                inputFormat = InputFormat.bytearray
+        else:
+            field.Size = 0
+            field.VariableSize = token["size"]
+
+        if "format" in token and token["format"] != None:
+            inputFormat = InputFormat[token["format"]]
+
+        field.Format = inputFormat
+
+        if "default" in token and token["default"] != None:
+            field.DefaultValue = token["default"]
+            ret, _ = ExpressionConverter.Verify(field.Format, field.DefaultValue)
+            if not ret:
+                return None
+
+        if "readonly" in token and token["readonly"] == "true" or field.IsReserved:
+            field.IsReadonly = True
+        if "autoincrease" in token and token["autoincrease"] == "true":
+            field.IsAutoIncrease = True
+            field.IsReadonly = True
+        if "increaselength" in token and token["increaselength"] == "true":
+            field.IsIncreaseLength = True
+        if "optional" in token:
+            field.Optional = token["optional"]
+
+        return field