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# Copyright (C) 2011, 2012 Nippon Telegraph and Telephone Corporation.
# Copyright (C) 2011, 2012 Isaku Yamahata <yamahata at valinux co jp>
#
# 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.
"""
Basic OpenFlow handling including negotiation.
"""
import itertools
import logging
import warnings
import os_ken.base.app_manager
from os_ken.lib import hub
from os_ken import utils
from os_ken.controller import ofp_event
from os_ken.controller.controller import OpenFlowController
from os_ken.controller.handler import set_ev_handler
from os_ken.controller.handler import CONFIG_DISPATCHER
from os_ken.controller.handler import HANDSHAKE_DISPATCHER
from os_ken.controller.handler import MAIN_DISPATCHER
from os_ken.ofproto import ofproto_parser
# The state transition: HANDSHAKE -> CONFIG -> MAIN
#
# HANDSHAKE: if it receives HELLO message with the valid OFP version,
# sends Features Request message, and moves to CONFIG.
#
# CONFIG: it receives Features Reply message and moves to MAIN
#
# MAIN: it does nothing. Applications are expected to register their
# own handlers.
#
# Note that at any state, when we receive Echo Request message, send
# back Echo Reply message.
class OFPHandler(os_ken.base.app_manager.OSKenApp):
def __init__(self, *args, **kwargs):
super(OFPHandler, self).__init__(*args, **kwargs)
self.name = ofp_event.NAME
self.controller = None
def start(self):
super(OFPHandler, self).start()
self.controller = OpenFlowController()
return hub.spawn(self.controller)
def _hello_failed(self, datapath, error_desc):
self.logger.error('%s on datapath %s', error_desc, datapath.address)
error_msg = datapath.ofproto_parser.OFPErrorMsg(
datapath=datapath,
type_=datapath.ofproto.OFPET_HELLO_FAILED,
code=datapath.ofproto.OFPHFC_INCOMPATIBLE,
data=error_desc)
datapath.send_msg(error_msg, close_socket=True)
@set_ev_handler(ofp_event.EventOFPHello, HANDSHAKE_DISPATCHER)
def hello_handler(self, ev):
self.logger.debug('hello ev %s', ev)
msg = ev.msg
datapath = msg.datapath
# check if received version is supported.
# pre 1.0 is not supported
elements = getattr(msg, 'elements', None)
if elements:
switch_versions = set()
for version in itertools.chain.from_iterable(
element.versions for element in elements):
switch_versions.add(version)
usable_versions = switch_versions & set(
datapath.supported_ofp_version)
# We didn't send our supported versions for interoperability as
# most switches would not understand elements at the moment.
# So the switch would think that the negotiated version would
# be max(negotiated_versions), but actual usable version is
# max(usable_versions).
negotiated_versions = set(
version for version in switch_versions
if version <= max(datapath.supported_ofp_version))
if negotiated_versions and not usable_versions:
# e.g.
# versions of OF 1.0 and 1.1 from switch
# max of OF 1.2 from OSKen and supported_ofp_version = (1.2, )
# negotiated version = 1.1
# usable version = None
error_desc = (
'no compatible version found: '
'switch versions %s controller version 0x%x, '
'the negotiated version is 0x%x, '
'but no usable version found. '
'If possible, set the switch to use one of OF version %s'
% (switch_versions, max(datapath.supported_ofp_version),
max(negotiated_versions),
sorted(datapath.supported_ofp_version)))
self._hello_failed(datapath, error_desc)
return
if (negotiated_versions and usable_versions and
max(negotiated_versions) != max(usable_versions)):
# e.g.
# versions of OF 1.0 and 1.1 from switch
# max of OF 1.2 from OSKen and supported_ofp_version = (1.0, 1.2)
# negotiated version = 1.1
# usable version = 1.0
#
# TODO: In order to get the version 1.0, OSKen need to send
# supported verions.
error_desc = (
'no compatible version found: '
'switch versions 0x%x controller version 0x%x, '
'the negotiated version is %s but found usable %s. '
'If possible, '
'set the switch to use one of OF version %s' % (
max(switch_versions),
max(datapath.supported_ofp_version),
sorted(negotiated_versions),
sorted(usable_versions), sorted(usable_versions)))
self._hello_failed(datapath, error_desc)
return
else:
usable_versions = set(version for version
in datapath.supported_ofp_version
if version <= msg.version)
if (usable_versions and
max(usable_versions) != min(msg.version,
datapath.ofproto.OFP_VERSION)):
# The version of min(msg.version, datapath.ofproto.OFP_VERSION)
# should be used according to the spec. But we can't.
# So log it and use max(usable_versions) with the hope that
# the switch is able to understand lower version.
# e.g.
# OF 1.1 from switch
# OF 1.2 from OSKen and supported_ofp_version = (1.0, 1.2)
# In this case, 1.1 should be used according to the spec,
# but 1.1 can't be used.
#
# OF1.3.1 6.3.1
# Upon receipt of this message, the recipient must
# calculate the OpenFlow protocol version to be used. If
# both the Hello message sent and the Hello message
# received contained a OFPHET_VERSIONBITMAP hello element,
# and if those bitmaps have some common bits set, the
# negotiated version must be the highest version set in
# both bitmaps. Otherwise, the negotiated version must be
# the smaller of the version number that was sent and the
# one that was received in the version fields. If the
# negotiated version is supported by the recipient, then
# the connection proceeds. Otherwise, the recipient must
# reply with an OFPT_ERROR message with a type field of
# OFPET_HELLO_FAILED, a code field of OFPHFC_INCOMPATIBLE,
# and optionally an ASCII string explaining the situation
# in data, and then terminate the connection.
version = max(usable_versions)
error_desc = (
'no compatible version found: '
'switch 0x%x controller 0x%x, but found usable 0x%x. '
'If possible, set the switch to use OF version 0x%x' % (
msg.version, datapath.ofproto.OFP_VERSION,
version, version))
self._hello_failed(datapath, error_desc)
return
if not usable_versions:
error_desc = (
'unsupported version 0x%x. '
'If possible, set the switch to use one of the versions %s' % (
msg.version, sorted(datapath.supported_ofp_version)))
self._hello_failed(datapath, error_desc)
return
datapath.set_version(max(usable_versions))
# Move on to config state
self.logger.debug('move onto config mode')
datapath.set_state(CONFIG_DISPATCHER)
# Finally, send feature request
features_request = datapath.ofproto_parser.OFPFeaturesRequest(datapath)
datapath.send_msg(features_request)
@set_ev_handler(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
def switch_features_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
self.logger.debug('switch features ev %s', msg)
datapath.id = msg.datapath_id
# hacky workaround, will be removed. OF1.3 doesn't have
# ports. An application should not depend on them. But there
# might be such bad applications so keep this workaround for
# while.
if datapath.ofproto.OFP_VERSION < 0x04:
datapath.ports = msg.ports
else:
datapath.ports = {}
if datapath.ofproto.OFP_VERSION < 0x04:
self.logger.debug('move onto main mode')
ev.msg.datapath.set_state(MAIN_DISPATCHER)
else:
port_desc = datapath.ofproto_parser.OFPPortDescStatsRequest(
datapath, 0)
datapath.send_msg(port_desc)
@set_ev_handler(ofp_event.EventOFPPortDescStatsReply, CONFIG_DISPATCHER)
def multipart_reply_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
with warnings.catch_warnings():
warnings.simplefilter('ignore')
for port in msg.body:
datapath.ports[port.port_no] = port
if msg.flags & datapath.ofproto.OFPMPF_REPLY_MORE:
return
self.logger.debug('move onto main mode')
ev.msg.datapath.set_state(MAIN_DISPATCHER)
@set_ev_handler(ofp_event.EventOFPEchoRequest,
[HANDSHAKE_DISPATCHER, CONFIG_DISPATCHER, MAIN_DISPATCHER])
def echo_request_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
echo_reply = datapath.ofproto_parser.OFPEchoReply(datapath)
echo_reply.xid = msg.xid
echo_reply.data = msg.data
datapath.send_msg(echo_reply)
@set_ev_handler(ofp_event.EventOFPEchoReply,
[HANDSHAKE_DISPATCHER, CONFIG_DISPATCHER, MAIN_DISPATCHER])
def echo_reply_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
datapath.acknowledge_echo_reply(msg.xid)
@set_ev_handler(ofp_event.EventOFPPortStatus, MAIN_DISPATCHER)
def port_status_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
if msg.reason in [ofproto.OFPPR_ADD, ofproto.OFPPR_MODIFY]:
datapath.ports[msg.desc.port_no] = msg.desc
elif msg.reason == ofproto.OFPPR_DELETE:
datapath.ports.pop(msg.desc.port_no, None)
else:
return
self.send_event_to_observers(
ofp_event.EventOFPPortStateChange(
datapath, msg.reason, msg.desc.port_no),
datapath.state)
@set_ev_handler(ofp_event.EventOFPErrorMsg,
[HANDSHAKE_DISPATCHER, CONFIG_DISPATCHER, MAIN_DISPATCHER])
def error_msg_handler(self, ev):
msg = ev.msg
ofp = msg.datapath.ofproto
self.logger.debug(
"EventOFPErrorMsg received.\n"
"version=%s, msg_type=%s, msg_len=%s, xid=%s\n"
" `-- msg_type: %s",
hex(msg.version), hex(msg.msg_type), hex(msg.msg_len),
hex(msg.xid),
ofp.ofp_msg_type_to_str(msg.msg_type))
if msg.type == ofp.OFPET_EXPERIMENTER:
self.logger.debug(
"OFPErrorExperimenterMsg(type=%s, exp_type=%s,"
" experimenter=%s, data=b'%s')",
hex(msg.type), hex(msg.exp_type),
hex(msg.experimenter), utils.binary_str(msg.data))
else:
self.logger.debug(
"OFPErrorMsg(type=%s, code=%s, data=b'%s')\n"
" |-- type: %s\n"
" |-- code: %s",
hex(msg.type), hex(msg.code), utils.binary_str(msg.data),
ofp.ofp_error_type_to_str(msg.type),
ofp.ofp_error_code_to_str(msg.type, msg.code))
if msg.type == ofp.OFPET_HELLO_FAILED:
self.logger.debug(
" `-- data: %s", msg.data.decode('ascii'))
elif len(msg.data) >= ofp.OFP_HEADER_SIZE:
(version, msg_type, msg_len, xid) = ofproto_parser.header(msg.data)
self.logger.debug(
" `-- data: version=%s, msg_type=%s, msg_len=%s, xid=%s\n"
" `-- msg_type: %s",
hex(version), hex(msg_type), hex(msg_len), hex(xid),
ofp.ofp_msg_type_to_str(msg_type))
else:
self.logger.warning(
"The data field sent from the switch is too short: "
"len(msg.data) < OFP_HEADER_SIZE\n"
"The OpenFlow Spec says that the data field should contain "
"at least 64 bytes of the failed request.\n"
"Please check the settings or implementation of your switch.")
|
