Initial set of Fabric switch test cases

Change-Id: I86fd2b67d3b773aa496f5ef61f1e1fdf51fd9925
diff --git a/Fabric/Utilities/src/python/loxi/generic_util.py b/Fabric/Utilities/src/python/loxi/generic_util.py
new file mode 100644
index 0000000..90aa672
--- /dev/null
+++ b/Fabric/Utilities/src/python/loxi/generic_util.py
@@ -0,0 +1,116 @@
+
+# Copyright 2017-present Open Networking Foundation
+#
+# 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.
+
+
+# Copyright (c) 2008 The Board of Trustees of The Leland Stanford Junior University
+# Copyright (c) 2011, 2012 Open Networking Foundation
+# Copyright (c) 2012, 2013 Big Switch Networks, Inc.
+# See the file LICENSE.pyloxi which should have been included in the source distribution
+"""
+Utility functions independent of the protocol version
+"""
+
+# Automatically generated by LOXI from template generic_util.py
+# Do not modify
+
+import loxi
+import struct
+
+def pack_list(values):
+    return "".join([x.pack() for x in values])
+
+def unpack_list(reader, deserializer):
+    """
+    The deserializer function should take an OFReader and return the new object.
+    """
+    entries = []
+    while not reader.is_empty():
+        entries.append(deserializer(reader))
+    return entries
+
+def pad_to(alignment, length):
+    """
+    Return a string of zero bytes that will pad a string of length 'length' to
+    a multiple of 'alignment'.
+    """
+    return "\x00" * ((length + alignment - 1)/alignment*alignment - length)
+
+class OFReader(object):
+    """
+    Cursor over a read-only buffer
+
+    OpenFlow messages are best thought of as a sequence of elements of
+    variable size, rather than a C-style struct with fixed offsets and
+    known field lengths. This class supports efficiently reading
+    fields sequentially and is intended to be used recursively by the
+    parsers of child objects which will implicitly update the offset.
+
+    buf: buffer object
+    start: initial position in the buffer
+    length: number of bytes after start
+    offset: distance from start
+    """
+    def __init__(self, buf, start=0, length=None):
+        self.buf = buf
+        self.start = start
+        if length is None:
+            self.length = len(buf) - start
+        else:
+            self.length = length
+        self.offset = 0
+
+    def read(self, fmt):
+        st = struct.Struct(fmt)
+        if self.offset + st.size > self.length:
+            raise loxi.ProtocolError("Buffer too short")
+        result = st.unpack_from(self.buf, self.start+self.offset)
+        self.offset += st.size
+        return result
+
+    def read_all(self):
+        s = self.buf[(self.start+self.offset):(self.start+self.length)]
+        assert(len(s) == self.length - self.offset)
+        self.offset = self.length
+        return s
+
+    def peek(self, fmt, offset=0):
+        st = struct.Struct(fmt)
+        if self.offset + offset + st.size > self.length:
+            raise loxi.ProtocolError("Buffer too short")
+        result = st.unpack_from(self.buf, self.start + self.offset + offset)
+        return result
+
+    def skip(self, length):
+        if self.offset + length > self.length:
+            raise loxi.ProtocolError("Buffer too short")
+        self.offset += length
+
+    def skip_align(self):
+        new_offset = (self.offset + 7) / 8 * 8
+        if new_offset > self.length:
+            raise loxi.ProtocolError("Buffer too short")
+        self.offset = new_offset
+
+    def is_empty(self):
+        return self.offset == self.length
+
+    # Used when parsing objects that have their own length fields
+    def slice(self, length, rewind=0):
+        if self.offset + length - rewind > self.length:
+            raise loxi.ProtocolError("Buffer too short")
+        reader = OFReader(self.buf, self.start + self.offset - rewind, length)
+        reader.skip(rewind)
+        self.offset += length - rewind
+        return reader