-
Notifications
You must be signed in to change notification settings - Fork 0
/
ofp_handler.py
312 lines (284 loc) · 13.4 KB
/
ofp_handler.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
# 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 ryu.base.app_manager
from ryu.lib import hub
from ryu import utils
from ryu.controller import ofp_event
from ryu.controller.controller import OpenFlowController
from ryu.controller.handler import set_ev_handler
from ryu.controller.handler import HANDSHAKE_DISPATCHER, CONFIG_DISPATCHER,\
MAIN_DISPATCHER
from ryu.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(ryu.base.app_manager.RyuApp):
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 Ryu 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 Ryu 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, Ryu 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 Ryu 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))
# <------------------------ fix version bug -------------------->
if ofp.OFP_VERSION > 0x01 and 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.")