Merge pull request #317 from renanrodrigo/add_hello_msg

Add Hello message

Author: beraldoleal

pyof/v0x04/symmetric/hello.py

@@ -2,7 +2,103 @@
 
 # System imports
 
+from enum import Enum
+
+from pyof.foundation.base import GenericMessage, GenericStruct
+from pyof.foundation.basic_types import BinaryData, FixedTypeList, UBInt16
+from pyof.v0x04.common.header import Header, Type
+
 # Third-party imports
 
-from pyof.v0x01.symmetric.hello import Hello
-__all__ = ('Hello',)
+
+__all__ = ('Hello', 'HelloElemHeader', 'HelloElemType',
+           'HelloElemVersionbitmap', 'ListOfHelloElements')
+
+# Enums
+
+
+class HelloElemType(Enum):
+    """Hello element types."""
+
+    #: Bitmap of version supported.
+    OFPHET_VERSIONBITMAP = 1
+
+
+# Classes
+
+
+class HelloElemHeader(GenericStruct):
+    """Common header for all Hello Elements."""
+
+    element_type = UBInt16(enum_ref=HelloElemType)
+    length = UBInt16()
+
+    def __init__(self, element_type=None, length=None):
+        """The constructor just assigns parameters to object attributes.
+
+        Args:
+            element_type: One of OFPHET_*.
+            length: Length in bytes of the element, including this header,
+                excluding padding.
+        """
+        super().__init__()
+        self.element_type = element_type
+        self.length = length
+
+
+class ListOfHelloElements(FixedTypeList):
+    """List of Hello elements.
+
+    Represented by instances of HelloElemHeader and used on Hello
+    objects.
+    """
+
+    def __init__(self, items=None):
+        """The constructor just assigns parameters to object attributes.
+
+        Args:
+            items (HelloElemHeader): Instance or a list of instances.
+        """
+        super().__init__(pyof_class=HelloElemHeader, items=items)
+
+
+class Hello(GenericMessage):
+    """OpenFlow Hello Message OFPT_HELLO.
+
+    This message includes zero or more hello elements having variable size.
+    Unknown element types must be ignored/skipped, to allow for future
+    extensions.
+    """
+
+    header = Header(message_type=Type.OFPT_HELLO)
+    #: Hello element list
+    elements = ListOfHelloElements()
+
+    def __init__(self, xid=None, elements=None):
+        """The constructor takes the parameters below.
+
+        Args:
+            xid (int): xid to be used on the message header.
+            elements: List of elements - 0 or more
+        """
+        super().__init__(xid)
+        self.elements = elements
+
+
+class HelloElemVersionbitmap(HelloElemHeader):
+    """Version bitmap Hello Element."""
+
+    #: List of bitmaps - supported versions
+    bitmaps = BinaryData()
+
+    def __init__(self, bitmaps=b''):
+        """The constructor just assigns parameters to object attributes.
+
+        Args:
+            bitmaps: -Exactly (length - 4) bytes containing the bitmaps,then
+                     -Exactly (length + 7)/8*8 - (length) (between 0 and 7)
+                      bytes of all-zero bytes.
+        """
+        super().__init__(element_type=HelloElemType.OFPHET_VERSIONBITMAP,
+                         length=None)
+        self.bitmaps = bitmaps