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1 /*
2 * Copyright (c) 2012 Nicira, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef OFP_MSGS_H
18 #define OFP_MSGS_H 1
19
20 /* OpenFlow message headers abstraction.
21 *
22 * OpenFlow headers are unnecessarily complicated:
23 *
24 * - Some messages with the same meaning were renumbered between 1.0 and 1.1.
25 *
26 * - "Statistics" (aka multipart) messages have a different format from other
27 * messages.
28 *
29 * - The 1.0 header for statistics messages is an odd number of 32-bit words
30 * long, leaving 64-bit quantities in the body misaligned. The 1.1 header
31 * for statistics added a padding word to fix this misalignment, although
32 * many statistic message bodies did not change.
33 *
34 * - Vendor-defined messages have an additional header but no standard way to
35 * distinguish individual types of message within a given vendor.
36 *
37 * This file attempts to abstract out the differences between the various forms
38 * of headers.
39 */
40
41 #include "openvswitch/types.h"
42 #include "ofp-errors.h"
43 #include "util.h"
44
45 struct list;
46 \f
47 /* Raw identifiers for OpenFlow messages.
48 *
49 * Some OpenFlow messages with similar meanings have multiple variants across
50 * OpenFlow versions or vendor extensions. Each variant has a different
51 * OFPRAW_* enumeration constant. More specifically, if two messages have
52 * different types, different numbers, or different arguments, then they must
53 * have different OFPRAW_* values.
54 *
55 * The comments here must follow a stylized form because the "extract-ofp-msgs"
56 * program parses them at build time to generate data tables. The syntax of
57 * each comment is:
58 *
59 * type versions (number): arguments.
60 *
61 * where the syntax of each part is:
62 *
63 * - type: One of OFPT (standard OpenFlow message), OFPST (standard OpenFlow
64 * statistics message), NXT (Nicira extension message), or NXST (Nicira
65 * extension statistics message).
66 *
67 * As new vendors implement extensions it will make sense to expand the
68 * dictionary of possible types.
69 *
70 * - versions: The OpenFlow version or versions in which this message is
71 * supported, e.g. "1.0" or "1.1" or "1.0+".
72 *
73 * - number:
74 * For OFPT, the 'type' in struct ofp_header.
75 * For OFPST, the 'type' in struct ofp_stats_msg or ofp11_stats_msg.
76 * For NXT, the 'subtype' in struct nicira_header.
77 * For NXST, the 'subtype' in struct nicira10_stats_msg or
78 * nicira11_stats_msg.
79 *
80 * - arguments: The types of data that follow the OpenFlow headers (the
81 * message "body"). This can be "void" if the message has no body.
82 * Otherwise, it should be a comma-separated sequence of C types. The
83 * last type in the sequence can end with [] if the body ends in a
84 * variable-length sequence.
85 *
86 * The arguments are used to validate the lengths of messages when a
87 * header is parsed. Any message whose length isn't valid as a length of
88 * the specified types will be rejected with OFPERR_OFPBRC_BAD_LEN.
89 *
90 * A few OpenFlow messages, such as OFPT_PACKET_IN, intentionally end with
91 * only part of a structure, up to some specified member. The syntax "up
92 * to <member>" indicates this, e.g. "struct ofp11_packet_in up to data".
93 */
94 enum ofpraw {
95 /* Standard messages. */
96
97 /* OFPT 1.0+ (0): uint8_t[]. */
98 OFPRAW_OFPT_HELLO,
99
100 /* OFPT 1.0+ (1): struct ofp_error_msg, uint8_t[]. */
101 OFPRAW_OFPT_ERROR,
102
103 /* OFPT 1.0+ (2): uint8_t[]. */
104 OFPRAW_OFPT_ECHO_REQUEST,
105
106 /* OFPT 1.0+ (3): uint8_t[]. */
107 OFPRAW_OFPT_ECHO_REPLY,
108
109 /* OFPT 1.0+ (5): void. */
110 OFPRAW_OFPT_FEATURES_REQUEST,
111
112 /* OFPT 1.0 (6): struct ofp_switch_features, struct ofp10_phy_port[]. */
113 OFPRAW_OFPT10_FEATURES_REPLY,
114 /* OFPT 1.1+ (6): struct ofp_switch_features, struct ofp11_port[]. */
115 OFPRAW_OFPT11_FEATURES_REPLY,
116
117 /* OFPT 1.0+ (7): void. */
118 OFPRAW_OFPT_GET_CONFIG_REQUEST,
119
120 /* OFPT 1.0+ (8): struct ofp_switch_config. */
121 OFPRAW_OFPT_GET_CONFIG_REPLY,
122
123 /* OFPT 1.0+ (9): struct ofp_switch_config. */
124 OFPRAW_OFPT_SET_CONFIG,
125
126 /* OFPT 1.0 (10): struct ofp_packet_in up to data, uint8_t[]. */
127 OFPRAW_OFPT10_PACKET_IN,
128 /* OFPT 1.1 (10): struct ofp11_packet_in up to data, uint8_t[]. */
129 OFPRAW_OFPT11_PACKET_IN,
130 /* OFPT 1.2 (10): struct ofp12_packet_in, uint8_t[]. */
131 OFPRAW_OFPT12_PACKET_IN,
132 /* NXT 1.0+ (17): struct nx_packet_in, uint8_t[]. */
133 OFPRAW_NXT_PACKET_IN,
134
135 /* OFPT 1.0 (11): struct ofp_flow_removed. */
136 OFPRAW_OFPT10_FLOW_REMOVED,
137 /* OFPT 1.1+ (11): struct ofp11_flow_removed, uint8_t[8][]. */
138 OFPRAW_OFPT11_FLOW_REMOVED,
139 /* NXT 1.0+ (14): struct nx_flow_removed, uint8_t[8][]. */
140 OFPRAW_NXT_FLOW_REMOVED,
141
142 /* OFPT 1.0 (12): struct ofp_port_status, struct ofp10_phy_port. */
143 OFPRAW_OFPT10_PORT_STATUS,
144 /* OFPT 1.1+ (12): struct ofp_port_status, struct ofp11_port. */
145 OFPRAW_OFPT11_PORT_STATUS,
146
147 /* OFPT 1.0 (13): struct ofp_packet_out, uint8_t[]. */
148 OFPRAW_OFPT10_PACKET_OUT,
149 /* OFPT 1.1+ (13): struct ofp11_packet_out, uint8_t[]. */
150 OFPRAW_OFPT11_PACKET_OUT,
151
152 /* OFPT 1.0 (14): struct ofp10_flow_mod, struct ofp_action_header[]. */
153 OFPRAW_OFPT10_FLOW_MOD,
154 /* OFPT 1.1+ (14): struct ofp11_flow_mod, struct ofp11_instruction[]. */
155 OFPRAW_OFPT11_FLOW_MOD,
156 /* NXT 1.0+ (13): struct nx_flow_mod, uint8_t[8][]. */
157 OFPRAW_NXT_FLOW_MOD,
158
159 /* OFPT 1.0 (15): struct ofp10_port_mod. */
160 OFPRAW_OFPT10_PORT_MOD,
161 /* OFPT 1.1+ (16): struct ofp11_port_mod. */
162 OFPRAW_OFPT11_PORT_MOD,
163
164 /* OFPT 1.0 (18): void. */
165 OFPRAW_OFPT10_BARRIER_REQUEST,
166 /* OFPT 1.1+ (20): void. */
167 OFPRAW_OFPT11_BARRIER_REQUEST,
168
169 /* OFPT 1.0 (19): void. */
170 OFPRAW_OFPT10_BARRIER_REPLY,
171 /* OFPT 1.1+ (21): void. */
172 OFPRAW_OFPT11_BARRIER_REPLY,
173
174 /* Standard statistics. */
175
176 /* OFPST 1.0+ (0): void. */
177 OFPRAW_OFPST_DESC_REQUEST,
178
179 /* OFPST 1.0+ (0): struct ofp_desc_stats. */
180 OFPRAW_OFPST_DESC_REPLY,
181
182 /* OFPST 1.0 (1): struct ofp10_flow_stats_request. */
183 OFPRAW_OFPST10_FLOW_REQUEST,
184 /* OFPST 1.1+ (1): struct ofp11_flow_stats_request, uint8_t[8][]. */
185 OFPRAW_OFPST11_FLOW_REQUEST,
186 /* NXST 1.0 (0): struct nx_flow_stats_request, uint8_t[8][]. */
187 OFPRAW_NXST_FLOW_REQUEST,
188
189 /* OFPST 1.0 (1): uint8_t[]. */
190 OFPRAW_OFPST10_FLOW_REPLY,
191 /* OFPST 1.1+ (1): uint8_t[]. */
192 OFPRAW_OFPST11_FLOW_REPLY,
193 /* NXST 1.0 (0): uint8_t[]. */
194 OFPRAW_NXST_FLOW_REPLY,
195
196 /* OFPST 1.0 (2): struct ofp10_flow_stats_request. */
197 OFPRAW_OFPST10_AGGREGATE_REQUEST,
198 /* OFPST 1.1+ (2): struct ofp11_flow_stats_request, uint8_t[8][]. */
199 OFPRAW_OFPST11_AGGREGATE_REQUEST,
200 /* NXST 1.0 (1): struct nx_flow_stats_request, uint8_t[8][]. */
201 OFPRAW_NXST_AGGREGATE_REQUEST,
202
203 /* OFPST 1.0+ (2): struct ofp_aggregate_stats_reply. */
204 OFPRAW_OFPST_AGGREGATE_REPLY,
205 /* NXST 1.0 (1): struct ofp_aggregate_stats_reply. */
206 OFPRAW_NXST_AGGREGATE_REPLY,
207
208 /* OFPST 1.0-1.2 (3): void. */
209 OFPRAW_OFPST_TABLE_REQUEST,
210
211 /* OFPST 1.0 (3): struct ofp10_table_stats[]. */
212 OFPRAW_OFPST10_TABLE_REPLY,
213 /* OFPST 1.1 (3): struct ofp11_table_stats[]. */
214 OFPRAW_OFPST11_TABLE_REPLY,
215 /* OFPST 1.2 (3): struct ofp12_table_stats[]. */
216 OFPRAW_OFPST12_TABLE_REPLY,
217
218 /* OFPST 1.0 (4): struct ofp10_port_stats_request. */
219 OFPRAW_OFPST10_PORT_REQUEST,
220 /* OFPST 1.1+ (4): struct ofp11_port_stats_request. */
221 OFPRAW_OFPST11_PORT_REQUEST,
222
223 /* OFPST 1.0 (4): struct ofp10_port_stats[]. */
224 OFPRAW_OFPST10_PORT_REPLY,
225 /* OFPST 1.1+ (4): struct ofp11_port_stats[]. */
226 OFPRAW_OFPST11_PORT_REPLY,
227
228 /* OFPST 1.0 (5): struct ofp10_queue_stats_request. */
229 OFPRAW_OFPST10_QUEUE_REQUEST,
230 /* OFPST 1.1+ (5): struct ofp11_queue_stats_request. */
231 OFPRAW_OFPST11_QUEUE_REQUEST,
232
233 /* OFPST 1.0 (5): struct ofp10_queue_stats[]. */
234 OFPRAW_OFPST10_QUEUE_REPLY,
235 /* OFPST 1.1+ (5): struct ofp11_queue_stats[]. */
236 OFPRAW_OFPST11_QUEUE_REPLY,
237
238 /* OFPST 1.0+ (13): void. */
239 OFPRAW_OFPST_PORT_DESC_REQUEST,
240
241 /* OFPST 1.0 (13): struct ofp10_phy_port[]. */
242 OFPRAW_OFPST10_PORT_DESC_REPLY,
243 /* OFPST 1.1+ (13): struct ofp11_port[]. */
244 OFPRAW_OFPST11_PORT_DESC_REPLY,
245
246 /* Nicira extension messages.
247 *
248 * Nicira extensions that correspond to standard OpenFlow messages are listed
249 * alongside the standard versions above. */
250
251 /* NXT 1.0+ (10): struct nx_role_request. */
252 OFPRAW_NXT_ROLE_REQUEST,
253
254 /* NXT 1.0+ (11): struct nx_role_request. */
255 OFPRAW_NXT_ROLE_REPLY,
256
257 /* NXT 1.0+ (12): struct nx_set_flow_format. */
258 OFPRAW_NXT_SET_FLOW_FORMAT,
259
260 /* NXT 1.0+ (15): struct nx_flow_mod_table_id. */
261 OFPRAW_NXT_FLOW_MOD_TABLE_ID,
262
263 /* NXT 1.0+ (16): struct nx_set_packet_in_format. */
264 OFPRAW_NXT_SET_PACKET_IN_FORMAT,
265
266 /* NXT 1.0+ (18): void. */
267 OFPRAW_NXT_FLOW_AGE,
268
269 /* NXT 1.0+ (19): struct nx_async_config. */
270 OFPRAW_NXT_SET_ASYNC_CONFIG,
271
272 /* NXT 1.0+ (20): struct nx_controller_id. */
273 OFPRAW_NXT_SET_CONTROLLER_ID,
274
275 /* NXT 1.0+ (21): struct nx_flow_monitor_cancel. */
276 OFPRAW_NXT_FLOW_MONITOR_CANCEL,
277
278 /* NXT 1.0+ (22): void. */
279 OFPRAW_NXT_FLOW_MONITOR_PAUSED,
280
281 /* NXT 1.0+ (23): void. */
282 OFPRAW_NXT_FLOW_MONITOR_RESUMED,
283
284 /* Nicira extension statistics.
285 *
286 * Nicira extension statistics that correspond to standard OpenFlow statistics
287 * are listed alongside the standard versions above. */
288
289 /* NXST 1.0 (2): uint8_t[8][]. */
290 OFPRAW_NXST_FLOW_MONITOR_REQUEST,
291
292 /* NXST 1.0 (2): uint8_t[8][]. */
293 OFPRAW_NXST_FLOW_MONITOR_REPLY,
294 };
295
296 /* Decoding messages into OFPRAW_* values. */
297 enum ofperr ofpraw_decode(enum ofpraw *, const struct ofp_header *);
298 enum ofperr ofpraw_pull(enum ofpraw *, struct ofpbuf *);
299 enum ofpraw ofpraw_pull_assert(struct ofpbuf *);
300
301 enum ofperr ofpraw_decode_partial(enum ofpraw *,
302 const struct ofp_header *, size_t length);
303
304 /* Encoding messages using OFPRAW_* values. */
305 struct ofpbuf *ofpraw_alloc(enum ofpraw, uint8_t ofp_version,
306 size_t extra_tailroom);
307 struct ofpbuf *ofpraw_alloc_xid(enum ofpraw, uint8_t ofp_version,
308 ovs_be32 xid, size_t extra_tailroom);
309 struct ofpbuf *ofpraw_alloc_reply(enum ofpraw,
310 const struct ofp_header *request,
311 size_t extra_tailroom);
312 struct ofpbuf *ofpraw_alloc_stats_reply(const struct ofp_header *request,
313 size_t extra_tailroom);
314
315 void ofpraw_put(enum ofpraw, uint8_t ofp_version, struct ofpbuf *);
316 void ofpraw_put_xid(enum ofpraw, uint8_t ofp_version, ovs_be32 xid,
317 struct ofpbuf *);
318 void ofpraw_put_reply(enum ofpraw, const struct ofp_header *request,
319 struct ofpbuf *);
320 void ofpraw_put_stats_reply(const struct ofp_header *request, struct ofpbuf *);
321
322 /* Information about OFPRAW_* values. */
323 const char *ofpraw_get_name(enum ofpraw);
324 enum ofpraw ofpraw_stats_request_to_reply(enum ofpraw, uint8_t version);
325 \f
326 /* Semantic identifiers for OpenFlow messages.
327 *
328 * Each OFPTYPE_* enumeration constant represents one or more concrete format
329 * of OpenFlow message. When two variants of a message have essentially the
330 * same meaning, they are assigned a single OFPTYPE_* value.
331 *
332 * The comments here must follow a stylized form because the "extract-ofp-msgs"
333 * program parses them at build time to generate data tables. The format is
334 * simply to list each OFPRAW_* enumeration constant for a given OFPTYPE_*,
335 * each followed by a period. */
336 enum ofptype {
337 /* Immutable messages. */
338 OFPTYPE_HELLO, /* OFPRAW_OFPT_HELLO. */
339 OFPTYPE_ERROR, /* OFPRAW_OFPT_ERROR. */
340 OFPTYPE_ECHO_REQUEST, /* OFPRAW_OFPT_ECHO_REQUEST. */
341 OFPTYPE_ECHO_REPLY, /* OFPRAW_OFPT_ECHO_REPLY. */
342
343 /* Switch configuration messages. */
344 OFPTYPE_FEATURES_REQUEST, /* OFPRAW_OFPT_FEATURES_REQUEST. */
345 OFPTYPE_FEATURES_REPLY, /* OFPRAW_OFPT10_FEATURES_REPLY.
346 * OFPRAW_OFPT11_FEATURES_REPLY. */
347 OFPTYPE_GET_CONFIG_REQUEST, /* OFPRAW_OFPT_GET_CONFIG_REQUEST. */
348 OFPTYPE_GET_CONFIG_REPLY, /* OFPRAW_OFPT_GET_CONFIG_REPLY. */
349 OFPTYPE_SET_CONFIG, /* OFPRAW_OFPT_SET_CONFIG. */
350
351 /* Asynchronous messages. */
352 OFPTYPE_PACKET_IN, /* OFPRAW_OFPT10_PACKET_IN.
353 * OFPRAW_OFPT11_PACKET_IN.
354 * OFPRAW_OFPT12_PACKET_IN.
355 * OFPRAW_NXT_PACKET_IN. */
356 OFPTYPE_FLOW_REMOVED, /* OFPRAW_OFPT10_FLOW_REMOVED.
357 * OFPRAW_OFPT11_FLOW_REMOVED.
358 * OFPRAW_NXT_FLOW_REMOVED. */
359 OFPTYPE_PORT_STATUS, /* OFPRAW_OFPT10_PORT_STATUS.
360 * OFPRAW_OFPT11_PORT_STATUS. */
361
362 /* Controller command messages. */
363 OFPTYPE_PACKET_OUT, /* OFPRAW_OFPT10_PACKET_OUT.
364 * OFPRAW_OFPT11_PACKET_OUT. */
365 OFPTYPE_FLOW_MOD, /* OFPRAW_OFPT10_FLOW_MOD.
366 * OFPRAW_OFPT11_FLOW_MOD.
367 * OFPRAW_NXT_FLOW_MOD. */
368 OFPTYPE_PORT_MOD, /* OFPRAW_OFPT10_PORT_MOD.
369 * OFPRAW_OFPT11_PORT_MOD. */
370
371 /* Barrier messages. */
372 OFPTYPE_BARRIER_REQUEST, /* OFPRAW_OFPT10_BARRIER_REQUEST.
373 * OFPRAW_OFPT11_BARRIER_REQUEST. */
374 OFPTYPE_BARRIER_REPLY, /* OFPRAW_OFPT10_BARRIER_REPLY.
375 * OFPRAW_OFPT11_BARRIER_REPLY. */
376
377 /* Statistics. */
378 OFPTYPE_DESC_STATS_REQUEST, /* OFPRAW_OFPST_DESC_REQUEST. */
379 OFPTYPE_DESC_STATS_REPLY, /* OFPRAW_OFPST_DESC_REPLY. */
380 OFPTYPE_FLOW_STATS_REQUEST, /* OFPRAW_OFPST10_FLOW_REQUEST.
381 * OFPRAW_OFPST11_FLOW_REQUEST.
382 * OFPRAW_NXST_FLOW_REQUEST. */
383 OFPTYPE_FLOW_STATS_REPLY, /* OFPRAW_OFPST10_FLOW_REPLY.
384 * OFPRAW_OFPST11_FLOW_REPLY.
385 * OFPRAW_NXST_FLOW_REPLY. */
386 OFPTYPE_AGGREGATE_STATS_REQUEST, /* OFPRAW_OFPST10_AGGREGATE_REQUEST.
387 * OFPRAW_OFPST11_AGGREGATE_REQUEST.
388 * OFPRAW_NXST_AGGREGATE_REQUEST. */
389 OFPTYPE_AGGREGATE_STATS_REPLY, /* OFPRAW_OFPST_AGGREGATE_REPLY.
390 * OFPRAW_NXST_AGGREGATE_REPLY. */
391 OFPTYPE_TABLE_STATS_REQUEST, /* OFPRAW_OFPST_TABLE_REQUEST. */
392 OFPTYPE_TABLE_STATS_REPLY, /* OFPRAW_OFPST10_TABLE_REPLY.
393 * OFPRAW_OFPST11_TABLE_REPLY.
394 * OFPRAW_OFPST12_TABLE_REPLY. */
395 OFPTYPE_PORT_STATS_REQUEST, /* OFPRAW_OFPST10_PORT_REQUEST.
396 * OFPRAW_OFPST11_PORT_REQUEST. */
397 OFPTYPE_PORT_STATS_REPLY, /* OFPRAW_OFPST10_PORT_REPLY.
398 * OFPRAW_OFPST11_PORT_REPLY. */
399 OFPTYPE_QUEUE_STATS_REQUEST, /* OFPRAW_OFPST10_QUEUE_REQUEST.
400 * OFPRAW_OFPST11_QUEUE_REQUEST. */
401 OFPTYPE_QUEUE_STATS_REPLY, /* OFPRAW_OFPST10_QUEUE_REPLY.
402 * OFPRAW_OFPST11_QUEUE_REPLY. */
403 OFPTYPE_PORT_DESC_STATS_REQUEST, /* OFPRAW_OFPST_PORT_DESC_REQUEST. */
404
405 OFPTYPE_PORT_DESC_STATS_REPLY, /* OFPRAW_OFPST10_PORT_DESC_REPLY.
406 * OFPRAW_OFPST11_PORT_DESC_REPLY. */
407
408 /* Nicira extensions. */
409 OFPTYPE_ROLE_REQUEST, /* OFPRAW_NXT_ROLE_REQUEST. */
410 OFPTYPE_ROLE_REPLY, /* OFPRAW_NXT_ROLE_REPLY. */
411 OFPTYPE_SET_FLOW_FORMAT, /* OFPRAW_NXT_SET_FLOW_FORMAT. */
412 OFPTYPE_FLOW_MOD_TABLE_ID, /* OFPRAW_NXT_FLOW_MOD_TABLE_ID. */
413 OFPTYPE_SET_PACKET_IN_FORMAT, /* OFPRAW_NXT_SET_PACKET_IN_FORMAT. */
414 OFPTYPE_FLOW_AGE, /* OFPRAW_NXT_FLOW_AGE. */
415 OFPTYPE_SET_ASYNC_CONFIG, /* OFPRAW_NXT_SET_ASYNC_CONFIG. */
416 OFPTYPE_SET_CONTROLLER_ID, /* OFPRAW_NXT_SET_CONTROLLER_ID. */
417
418 /* Flow monitor extension. */
419 OFPTYPE_FLOW_MONITOR_STATS_REQUEST, /* OFPRAW_NXST_FLOW_MONITOR_REQUEST. */
420 OFPTYPE_FLOW_MONITOR_STATS_REPLY, /* OFPRAW_NXST_FLOW_MONITOR_REPLY. */
421 OFPTYPE_FLOW_MONITOR_CANCEL, /* OFPRAW_NXT_FLOW_MONITOR_CANCEL. */
422 OFPTYPE_FLOW_MONITOR_PAUSED, /* OFPRAW_NXT_FLOW_MONITOR_PAUSED. */
423 OFPTYPE_FLOW_MONITOR_RESUMED, /* OFPRAW_NXT_FLOW_MONITOR_RESUMED. */
424 };
425
426 /* Decoding messages into OFPTYPE_* values. */
427 enum ofperr ofptype_decode(enum ofptype *, const struct ofp_header *);
428 enum ofperr ofptype_pull(enum ofptype *, struct ofpbuf *);
429 enum ofptype ofptype_from_ofpraw(enum ofpraw);
430 \f
431 /* OpenFlow message properties. */
432 void ofpmsg_update_length(struct ofpbuf *);
433 const void *ofpmsg_body(const struct ofp_header *);
434 \f
435 /* Multipart messages (aka "statistics").
436 *
437 * Individual OpenFlow messages are limited to 64 kB in size, but some messages
438 * need to be longer. Therefore, multipart messages allow a longer message to
439 * be divided into multiple parts at some convenient boundary. For example,
440 * limiting the response to a "flow dump" request to 64 kB would unreasonably
441 * limit the maximum number of flows in an OpenFlow switch, so a "flow dump" is
442 * expressed as a multipart request/reply pair, with the reply broken into
443 * pieces between flows.
444 *
445 * Multipart messages always consist of a request/reply pair.
446 *
447 * In OpenFlow 1.0, 1.1, and 1.2, requests must always fit in a single message,
448 * that is, only a multipart reply may have more than one part. OpenFlow 1.3
449 * adds one multipart request. This code does not yet support multipart
450 * requests. */
451
452 /* Encoding multipart replies.
453 *
454 * These functions are useful for multipart replies that might really require
455 * more than one message. A multipart message that is known in advance to fit
456 * within 64 kB doesn't need any special treatment, so you might as well use
457 * the ofpraw_alloc_*() functions.
458 *
459 * These functions work with a "struct list" of "struct ofpbuf"s, each of
460 * which represents one part of a multipart message. */
461 void ofpmp_init(struct list *, const struct ofp_header *request);
462 struct ofpbuf *ofpmp_reserve(struct list *, size_t len);
463 void *ofpmp_append(struct list *, size_t len);
464 void ofpmp_postappend(struct list *, size_t start_ofs);
465
466 /* Decoding multipart replies. */
467 uint16_t ofpmp_flags(const struct ofp_header *);
468 bool ofpmp_more(const struct ofp_header *);
469
470 #endif /* ofp-msgs.h */