Merge pull request #371 from renanrodrigo/add_ip_4

Add IPv4 network type class

Author: beraldoleal

CHANGELOG.rst

@@ -7,6 +7,7 @@ All notable changes to the python-openflow project is documented in this file.
 ********************************
 Added
 =====
+- IPv4 packet pack/unpack support.
 
 Changed
 =======

pyof/foundation/base.py

@@ -23,8 +23,8 @@
 from enum import Enum, IntEnum
 
 # Local source tree imports
-from pyof.foundation.exceptions import (BadValueException, PackException,
-                                        UnpackException, ValidationError)
+from pyof.foundation.exceptions import (
+    BadValueException, PackException, UnpackException, ValidationError)
 
 # Third-party imports
 

pyof/foundation/network_types.py

@@ -4,10 +4,11 @@
 """
 
 from pyof.foundation.base import GenericStruct
-from pyof.foundation.basic_types import BinaryData, HWAddress, UBInt8, UBInt16
+from pyof.foundation.basic_types import (
+    BinaryData, HWAddress, IPAddress, UBInt8, UBInt16)
 from pyof.foundation.exceptions import PackException
 
-__all__ = ('Ethernet', 'GenericTLV', 'TLVWithSubType', 'LLDP')
+__all__ = ('Ethernet', 'GenericTLV', 'IPv4', 'TLVWithSubType', 'LLDP')
 
 
 class Ethernet(GenericStruct):
@@ -138,6 +139,140 @@ def get_size(self, value=None):
         return 2 + self.length
 
 
+class IPv4(GenericStruct):
+    """IPv4 packet "struct".
+
+    Contains all fields of an IP version 4 packet header, plus the upper layer
+    content as binary data.
+    Some of the fields were merged together because of their size being
+    inferior to 8 bits. They are represented as a single class attribute, but
+    pack/unpack methods will take into account the values in individual
+    instance attributes.
+    """
+
+    #: _version_ihl (:class:`UBInt8`): IP protocol version + Internet Header
+    #: Length (words)
+    _version_ihl = UBInt8()
+    #: _dscp_ecn (:class:`UBInt8`): Differentiated Services Code Point
+    #: (ToS - Type of Service) + Explicit Congestion Notification
+    _dscp_ecn = UBInt8()
+    #: length (:class:`UBInt16`): IP packet length (bytes)
+    length = UBInt16()
+    #: identification (:class:`UBInt16`): Packet ID - common to all fragments
+    identification = UBInt16()
+    #: _flags_offset (:class:`UBInt16`): Fragmentation flags + fragmentation
+    #: offset
+    _flags_offset = UBInt16()
+    #: ttl (:class:`UBInt8`): Packet time-to-live
+    ttl = UBInt8()
+    #: protocol (:class:`UBInt8`): Upper layer protocol number
+    protocol = UBInt8()
+    #: checksum (:class:`UBInt16`): Header checksum
+    checksum = UBInt16()
+    #: source (:class:`IPAddress`): Source IPv4 address
+    source = IPAddress()
+    #: destination (:class:`IPAddress`): Destination IPv4 address
+    destination = IPAddress()
+    #: options (:class:`BinaryData`): IP Options - up to 320 bits, always
+    #: padded to 32 bits
+    options = BinaryData()
+    #: data (:class:`BinaryData`): Packet data
+    data = BinaryData()
+
+    def __init__(self, version=4, ihl=5, dscp=0, ecn=0, length=0, # noqa
+                 identification=0, flags=0, offset=0, ttl=255, protocol=0,
+                 checksum=0, source="0.0.0.0", destination="0.0.0.0",
+                 options=b'', data=b''):
+        """Create the Packet and set instance attributes."""
+        super().__init__()
+        self.version = version
+        self.ihl = ihl
+        self.dscp = dscp
+        self.ecn = ecn
+        self.length = length
+        self.identification = identification
+        self.flags = flags
+        self.offset = offset
+        self.ttl = ttl
+        self.protocol = protocol
+        self.checksum = checksum
+        self.source = source
+        self.destination = destination
+        self.options = options
+        self.data = data
+
+    def _update_checksum(self):
+        """Update the packet checksum to enable integrity check."""
+        source_list = [int(octet) for octet in self.source.split(".")]
+        destination_list = [int(octet) for octet in
+                            self.destination.split(".")]
+        source_upper = (source_list[0] << 8) + source_list[1]
+        source_lower = (source_list[2] << 8) + source_list[3]
+        destination_upper = (destination_list[0] << 8) + destination_list[1]
+        destination_lower = (destination_list[2] << 8) + destination_list[3]
+
+        block_sum = ((self._version_ihl << 8 | self._dscp_ecn) + self.length +
+                     self.identification + self._flags_offset +
+                     (self.ttl << 8 | self.protocol) + source_upper +
+                     source_lower + destination_upper + destination_lower)
+
+        while block_sum > 65535:
+            carry = block_sum >> 16
+            block_sum = (block_sum & 65535) + carry
+
+        self.checksum = ~block_sum & 65535
+
+    def pack(self, value=None):
+        """Pack the struct in a binary representation.
+
+        Merge some fields to ensure correct packing.
+        """
+        # Set the correct IHL based on options size
+        if self.options:
+            self.ihl += int(len(self.options) / 4)
+
+        # Set the correct packet length based on header length and data
+        self.length = int(self.ihl * 4 + len(self.data))
+
+        self._version_ihl = self.version << 4 | self.ihl
+        self._dscp_ecn = self.dscp << 2 | self.ecn
+        self._flags_offset = self.flags << 13 | self.offset
+
+        # Set the checksum field before packing
+        self._update_checksum()
+
+        return super().pack()
+
+    def unpack(self, buff, offset=0):
+        """Unpack a binary struct into this object's attributes.
+
+        Return the values instead of the lib's basic types.
+        """
+        super().unpack(buff, offset)
+
+        self.version = self._version_ihl.value >> 4
+        self.ihl = self._version_ihl.value & 15
+        self.dscp = self._dscp_ecn.value >> 2
+        self.ecn = self._dscp_ecn.value & 3
+        self.length = self.length.value
+        self.identification = self.identification.value
+        self.flags = self._flags_offset.value >> 13
+        self.offset = self._flags_offset.value & 8191
+        self.ttl = self.ttl.value
+        self.protocol = self.protocol.value
+        self.checksum = self.checksum.value
+        self.source = self.source.value
+        self.destination = self.destination.value
+
+        if self.ihl > 5:
+            options_size = (self.ihl - 5) * 4
+            self.data = self.options.value[options_size:]
+            self.options = self.options.value[:options_size]
+        else:
+            self.data = self.options.value
+            self.options = b''
+
+
 class TLVWithSubType(GenericTLV):
     """Modify the :class:`GenericTLV` to a Organization Specific TLV structure.
 

pyof/v0x01/asynchronous/packet_in.py

@@ -4,8 +4,8 @@
 from enum import IntEnum
 
 from pyof.foundation.base import GenericMessage
-from pyof.foundation.basic_types import (BinaryData, Pad, UBInt8, UBInt16,
-                                         UBInt32)
+from pyof.foundation.basic_types import (
+    BinaryData, Pad, UBInt8, UBInt16, UBInt32)
 from pyof.v0x01.common.constants import NO_BUFFER
 from pyof.v0x01.common.header import Header, Type
 

pyof/v0x01/common/action.py

@@ -4,8 +4,8 @@
 
 # Local source tree imports
 from pyof.foundation.base import GenericBitMask, GenericStruct
-from pyof.foundation.basic_types import (FixedTypeList, HWAddress, Pad, UBInt8,
-                                         UBInt16, UBInt32)
+from pyof.foundation.basic_types import (
+    FixedTypeList, HWAddress, Pad, UBInt8, UBInt16, UBInt32)
 from pyof.foundation.constants import UBINT16_MAX_VALUE
 
 # Third-party imports

pyof/v0x01/common/flow_match.py

@@ -6,8 +6,8 @@
 
 # Local source tree imports
 from pyof.foundation.base import GenericBitMask, GenericStruct
-from pyof.foundation.basic_types import (HWAddress, IPAddress, Pad, UBInt8,
-                                         UBInt16, UBInt32)
+from pyof.foundation.basic_types import (
+    HWAddress, IPAddress, Pad, UBInt8, UBInt16, UBInt32)
 
 __all__ = ('Match', 'FlowWildCards')
 

pyof/v0x01/common/phy_port.py

@@ -5,8 +5,8 @@
 
 # Local source tree imports
 from pyof.foundation.base import GenericBitMask, GenericStruct
-from pyof.foundation.basic_types import (Char, FixedTypeList, HWAddress,
-                                         UBInt16, UBInt32)
+from pyof.foundation.basic_types import (
+    Char, FixedTypeList, HWAddress, UBInt16, UBInt32)
 from pyof.foundation.constants import OFP_MAX_PORT_NAME_LEN
 
 # Third-party imports

pyof/v0x01/common/utils.py

@@ -21,10 +21,10 @@
 from pyof.v0x01.controller2switch.get_config_request import GetConfigRequest
 from pyof.v0x01.controller2switch.packet_out import PacketOut
 from pyof.v0x01.controller2switch.port_mod import PortMod
-from pyof.v0x01.controller2switch.queue_get_config_reply import \
-    QueueGetConfigReply
-from pyof.v0x01.controller2switch.queue_get_config_request import \
-    QueueGetConfigRequest
+from pyof.v0x01.controller2switch.queue_get_config_reply import (
+    QueueGetConfigReply)
+from pyof.v0x01.controller2switch.queue_get_config_request import (
+    QueueGetConfigRequest)
 from pyof.v0x01.controller2switch.set_config import SetConfig
 from pyof.v0x01.controller2switch.stats_reply import StatsReply
 from pyof.v0x01.controller2switch.stats_request import StatsRequest

pyof/v0x01/controller2switch/common.py

@@ -4,10 +4,10 @@
 from enum import IntEnum
 
 from pyof.foundation.base import GenericMessage, GenericStruct
-from pyof.foundation.basic_types import (Char, Pad, UBInt8, UBInt16, UBInt32,
-                                         UBInt64)
-from pyof.foundation.constants import (DESC_STR_LEN, OFP_MAX_TABLE_NAME_LEN,
-                                       SERIAL_NUM_LEN)
+from pyof.foundation.basic_types import (
+    Char, Pad, UBInt8, UBInt16, UBInt32, UBInt64)
+from pyof.foundation.constants import (
+    DESC_STR_LEN, OFP_MAX_TABLE_NAME_LEN, SERIAL_NUM_LEN)
 # Local source tree imports
 from pyof.v0x01.common.action import ListOfActions
 from pyof.v0x01.common.flow_match import FlowWildCards, Match

pyof/v0x04/asynchronous/packet_in.py

@@ -4,8 +4,8 @@
 from enum import IntEnum
 
 from pyof.foundation.base import GenericMessage
-from pyof.foundation.basic_types import (BinaryData, Pad, UBInt8, UBInt16,
-                                         UBInt32, UBInt64)
+from pyof.foundation.basic_types import (
+    BinaryData, Pad, UBInt8, UBInt16, UBInt32, UBInt64)
 from pyof.v0x04.common.flow_match import Match
 from pyof.v0x04.common.header import Header, Type