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/parsegraph/nodes/ipv4.json b/extras/packetforge/parsegraph/nodes/ipv4.json
new file mode 100644
index 0000000..297f600
--- /dev/null
+++ b/extras/packetforge/parsegraph/nodes/ipv4.json
@@ -0,0 +1,76 @@
+{
+    "type" : "node",
+    "name" : "ipv4",
+    "layout" : [
+        {
+            "name" : "version",
+            "size" : "4",
+            "default" : "4",
+            "readonly" : "true"
+        },
+        {
+            "name" : "ilh",
+            "size" : "4",
+            "default" : "5",
+            "readonly" : "true"
+        },
+        {
+            "name" : "dscp",
+            "size" : "6"
+        },
+        {
+            "name" : "ecn",
+            "size" : "2"
+        },
+        {
+            "name" : "totallength",
+            "size" : "16",
+            "default" : "20",
+            "autoincrease" : "true"
+        },
+        {
+            "name" : "identification",
+            "size" : "16"
+        },
+        {
+            "name" : "reserved",
+            "size" : "1"
+        },
+        {
+            "name" : "df",
+            "size" : "1"
+        },
+        {
+            "name" : "mf",
+            "size" : "1"
+        },
+        {
+            "name" : "fragmentoffset",
+            "size" : "13"
+        },
+        {
+            "name" : "ttl",
+            "size" : "8"
+        },
+        {
+            "name" : "protocol",
+            "size" : "8"
+        },
+        {
+            "name" : "checksum",
+            "size" : "16"
+        },
+        {
+            "name" : "src",
+            "size" : "32",
+            "format" : "ipv4",
+            "default" : "1.1.1.1"
+        },
+        {
+            "name" : "dst",
+            "size" : "32",
+            "format" : "ipv4",
+            "default" : "2.2.2.2"
+        }
+    ]
+}