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"""For packets received by the datapath and sent to the controller."""
# System imports
from enum import IntEnum
from pyof.foundation.base import GenericMessage
from pyof.foundation.basic_types import (
BinaryData, Pad, UBInt8, UBInt16, UBInt32, UBInt64)
from pyof.v0x04.common.flow_match import Match, OxmOfbMatchField
from pyof.v0x04.common.header import Header, Type
# Third-party imports
__all__ = ('PacketIn', 'PacketInReason')
# Enums
class PacketInReason(IntEnum):
"""Reason why this packet is being sent to the controller."""
#: matching flow (table-miss flow entry).
OFPR_NO_MATCH = 0
#: Action explicitly output to controller.
OFPR_ACTION = 1
#: Packet has invalid TTL.
OFPR_INVALID_TTL = 2
# Classes
class PacketIn(GenericMessage):
"""Packet received on port (datapath -> controller)."""
#: :class:`~pyof.v0x04.common.header.Header`: OpenFlow Header
header = Header(message_type=Type.OFPT_PACKET_IN)
#: ID assigned by datapath.
buffer_id = UBInt32()
#: Full length of frame.
total_len = UBInt16()
#: Reason packet is being sent (one of OFPR_*),
reason = UBInt8(enum_ref=PacketInReason)
#: ID of the table that was looked up.
table_id = UBInt8()
#: Cookie of the flow entry that was looked up.
cookie = UBInt64()
#: Packet metadata. Variable size.
match = Match()
#: Align to 64 bit + 16 bit
pad = Pad(2)
#: Ethernet frame whose length is inferred from header.length.
#: The padding bytes preceding the Ethernet frame ensure that the IP
#: header (if any) following the Ethernet header is 32-bit aligned.
data = BinaryData()
def __init__(self, xid=None, buffer_id=None, total_len=None, reason=None,
table_id=None, cookie=None, match=None, data=b''):
"""Assign parameters to object attributes.
Args:
xid (int): Header's xid.
buffer_id (int): ID assigned by datapath.
total_len (int): Full length of frame.
reason (~pyof.v0x04.asynchronous.packet_in.PacketInReason):
The reason why the packet is being sent
table_id (int): ID of the table that was looked up
cookie (int): Cookie of the flow entry that was looked up
match (:class:`~pyof.v0x04.common.flow_match.Match`):
Packet metadata with variable size.
data (bytes): Ethernet frame, halfway through 32-bit word, so the
IP header is 32-bit aligned. The amount of data is inferred
from the length field in the header. Because of padding,
offsetof(struct ofp_packet_in, data) ==
sizeof(struct ofp_packet_in) - 2.
"""
super().__init__(xid)
self.buffer_id = buffer_id
self.total_len = total_len
self.reason = reason
self.table_id = table_id
self.cookie = cookie
self.match = match
self.data = data
@property
def in_port(self):
"""Retrieve the 'in_port' that generated the PacketIn.
This method will look for the OXM_TLV with type OFPXMT_OFB_IN_PORT on
the `oxm_match_fields` field from `match` field and return its value,
if the OXM exists.
Returns:
The integer number of the 'in_port' that generated the PacketIn if
it exists. Otherwise return None.
"""
in_port = self.match.get_field(OxmOfbMatchField.OFPXMT_OFB_IN_PORT)
return int.from_bytes(in_port, 'big')
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