1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2019 Nicira, Inc.
2 * Copyright (C) 2016 Hewlett Packard Enterprise Development LP
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
20 /* Open vSwitch Database Interface Definition Language (OVSDB IDL).
22 * The OVSDB IDL maintains an in-memory replica of a database. It issues RPC
23 * requests to an OVSDB database server and parses the responses, converting
24 * raw JSON into data structures that are easier for clients to digest. Most
25 * notably, references to rows via UUID become C pointers.
27 * The IDL always presents a consistent snapshot of the database to its client,
28 * that is, it won't present the effects of some part of a transaction applied
29 * at the database server without presenting all of its effects.
31 * The IDL also assists with issuing database transactions. The client creates
32 * a transaction, manipulates the IDL data structures, and commits or aborts
33 * the transaction. The IDL then composes and issues the necessary JSON-RPC
34 * requests and reports to the client whether the transaction completed
41 #include "ovsdb-types.h"
42 #include "ovsdb-data.h"
43 #include "openvswitch/list.h"
44 #include "ovsdb-condition.h"
53 struct ovsdb_idl_class
;
55 struct ovsdb_idl_column
;
56 struct ovsdb_idl_table_class
;
59 struct ovsdb_idl
*ovsdb_idl_create(const char *remote
,
60 const struct ovsdb_idl_class
*,
61 bool monitor_everything_by_default
,
63 struct ovsdb_idl
*ovsdb_idl_create_unconnected(
64 const struct ovsdb_idl_class
*, bool monitor_everything_by_default
);
65 void ovsdb_idl_set_remote(struct ovsdb_idl
*, const char *, bool);
66 void ovsdb_idl_set_shuffle_remotes(struct ovsdb_idl
*, bool);
67 void ovsdb_idl_reset_min_index(struct ovsdb_idl
*);
68 void ovsdb_idl_destroy(struct ovsdb_idl
*);
70 void ovsdb_idl_set_leader_only(struct ovsdb_idl
*, bool leader_only
);
72 void ovsdb_idl_run(struct ovsdb_idl
*);
73 void ovsdb_idl_wait(struct ovsdb_idl
*);
75 void ovsdb_idl_set_lock(struct ovsdb_idl
*, const char *lock_name
);
76 bool ovsdb_idl_has_lock(const struct ovsdb_idl
*);
77 bool ovsdb_idl_is_lock_contended(const struct ovsdb_idl
*);
79 const struct uuid
* ovsdb_idl_get_monitor_id(const struct ovsdb_idl
*);
80 unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl
*);
81 bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl
*);
82 void ovsdb_idl_enable_reconnect(struct ovsdb_idl
*);
83 void ovsdb_idl_force_reconnect(struct ovsdb_idl
*);
84 void ovsdb_idl_verify_write_only(struct ovsdb_idl
*);
86 bool ovsdb_idl_is_alive(const struct ovsdb_idl
*);
87 bool ovsdb_idl_is_connected(const struct ovsdb_idl
*idl
);
88 int ovsdb_idl_get_last_error(const struct ovsdb_idl
*);
90 void ovsdb_idl_set_probe_interval(const struct ovsdb_idl
*, int probe_interval
);
92 void ovsdb_idl_check_consistency(const struct ovsdb_idl
*);
94 const struct ovsdb_idl_class
*ovsdb_idl_get_class(const struct ovsdb_idl
*);
95 const struct ovsdb_idl_table_class
*ovsdb_idl_table_class_from_column(
96 const struct ovsdb_idl_class
*, const struct ovsdb_idl_column
*);
98 /* Choosing columns and tables to replicate.
100 * The client may choose any subset of the columns and tables to replicate,
101 * specifying it one of two ways:
103 * - As a deny list (adding the columns or tables to replicate). To do so,
104 * the client passes false as 'monitor_everything_by_default' to
105 * ovsdb_idl_create() and then calls ovsdb_idl_add_column() and
106 * ovsdb_idl_add_table() for the desired columns and, if necessary, tables.
108 * - As an allow list (replicating all columns and tables except those
109 * explicitly removed). To do so, the client passes true as
110 * 'monitor_everything_by_default' to ovsdb_idl_create() and then calls
111 * ovsdb_idl_omit() to remove columns.
113 * There are multiple modes a column may be replicated:
115 * - Read-only. This is the default. Whenever the column changes in any
116 * replicated row, the value returned by ovsdb_idl_get_seqno() will change,
117 * letting the client know to look at the replicated data again.
119 * - Write-only. This is for columns that the client sets and updates but
120 * does not want to be alerted about its own updates (which, at the OVSDB
121 * level, cannot be distinguished from updates made by any other client).
122 * The column will be replicated in the same way as for read-only columns,
123 * but the value returned by ovsdb_idl_get_seqno() will not change when the
124 * column changes, saving wasted CPU time.
126 * (A "write-only" client probably does read the column so that it can know
127 * whether it needs to update it, but it doesn't expect to react to changes
130 * To mark a replicated column as write-only, a client calls
131 * ovsdb_idl_omit_alert(). (The column must already be replicated one of
132 * the ways described in the previous list.)
134 * This is an optimization only and does not affect behavioral correctness
135 * of an otherwise well-written client.
137 * - Read/write. In theory, an OVSDB client might both read and write a
138 * column, although OVSDB schemas are usually designed so that any given
139 * client only does one or the other. This is actually the same as
140 * read/write columns; that is, the client need take no special action.
143 /* Modes with which the IDL can replicate a column. See above comment for
146 * If no bits are set, the IDL does not replicate the column at all. The
147 * client will always see it with the default value for its type.
149 * If OVSDB_IDL_MONITOR is set, then the IDL replicates the column and sets it
150 * to to the value in the database. If OVSDB_IDL_ALERT is also set, then the
151 * IDL will change the value returned by ovsdb_idl_get_seqno() when the
152 * column's value changes in any row.
154 * The possible mode combinations are:
156 * - 0, for a column that a client doesn't care about. This is the default
157 * for every column in every table, if the client passes false for
158 * 'monitor_everything_by_default' to ovsdb_idl_create().
160 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants
161 * to track and possibly update. This is the default for every column in
162 * every table, if the client passes true for
163 * 'monitor_everything_by_default' to ovsdb_idl_create().
165 * - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only",
166 * that is, it updates them but doesn't want to get alerted about its own
167 * updates. It also won't be alerted about other clients' updates, so this
168 * is suitable only for use by a client that "owns" a particular column.
169 * Use ovsdb_idl_omit_alert() to set a column that is already replicated to
172 * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid.
174 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT | OVSDB_IDL_TRACK), for a column
175 * that a client wants to track using the change tracking
176 * ovsdb_idl_track_get_*() functions.
178 #define OVSDB_IDL_MONITOR (1 << 0) /* Replicate this column? */
179 #define OVSDB_IDL_ALERT (1 << 1) /* Alert client when column changes? */
180 #define OVSDB_IDL_TRACK (1 << 2)
182 void ovsdb_idl_add_column(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
183 void ovsdb_idl_add_table(struct ovsdb_idl
*,
184 const struct ovsdb_idl_table_class
*);
186 void ovsdb_idl_omit(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
187 void ovsdb_idl_omit_alert(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
191 * In OVSDB, change tracking is applied at each client in the IDL layer. This
192 * means that when a client makes a request to track changes on a particular
193 * table, they are essentially requesting information about the incremental
194 * changes to that table from the point in time that the request is made. Once
195 * the client clears tracked changes, that information will no longer be
198 * The implication of the above is that if a client requires replaying
199 * untracked history, it faces the choice of either trying to remember changes
200 * itself (which translates into a memory leak) or of being structured with a
201 * path for processing the full untracked table as well as a path that
202 * processes incremental changes. */
203 enum ovsdb_idl_change
{
204 OVSDB_IDL_CHANGE_INSERT
,
205 OVSDB_IDL_CHANGE_MODIFY
,
206 OVSDB_IDL_CHANGE_DELETE
,
210 /* Row, table sequence numbers */
211 unsigned int ovsdb_idl_table_get_seqno(
212 const struct ovsdb_idl
*idl
,
213 const struct ovsdb_idl_table_class
*table_class
);
214 unsigned int ovsdb_idl_row_get_seqno(
215 const struct ovsdb_idl_row
*row
,
216 enum ovsdb_idl_change change
);
218 void ovsdb_idl_track_add_column(struct ovsdb_idl
*idl
,
219 const struct ovsdb_idl_column
*column
);
220 void ovsdb_idl_track_add_all(struct ovsdb_idl
*idl
);
221 const struct ovsdb_idl_row
*ovsdb_idl_track_get_first(
222 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
223 const struct ovsdb_idl_row
*ovsdb_idl_track_get_next(const struct ovsdb_idl_row
*);
224 bool ovsdb_idl_track_is_updated(const struct ovsdb_idl_row
*row
,
225 const struct ovsdb_idl_column
*column
);
226 void ovsdb_idl_track_clear(struct ovsdb_idl
*);
229 /* Reading the database replica. */
231 const struct ovsdb_idl_row
*ovsdb_idl_get_row_for_uuid(
232 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*,
233 const struct uuid
*);
234 const struct ovsdb_idl_row
*ovsdb_idl_first_row(
235 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
236 const struct ovsdb_idl_row
*ovsdb_idl_next_row(const struct ovsdb_idl_row
*);
238 const struct ovsdb_datum
*ovsdb_idl_read(const struct ovsdb_idl_row
*,
239 const struct ovsdb_idl_column
*);
240 const struct ovsdb_datum
*ovsdb_idl_get(const struct ovsdb_idl_row
*,
241 const struct ovsdb_idl_column
*,
242 enum ovsdb_atomic_type key_type
,
243 enum ovsdb_atomic_type value_type
);
244 bool ovsdb_idl_is_mutable(const struct ovsdb_idl_row
*,
245 const struct ovsdb_idl_column
*);
247 bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row
*);
251 * A transaction may modify the contents of a database by modifying the values
252 * of columns, deleting rows, inserting rows, or adding checks that columns in
253 * the database have not changed ("verify" operations), through
254 * ovsdb_idl_txn_*() functions. (The OVSDB IDL code generator produces helper
255 * functions that internally call the ovsdb_idl_txn_*() functions. These are
256 * likely to be more convenient.)
258 * Reading and writing columns and inserting and deleting rows are all
259 * straightforward. The reasons to verify columns are less obvious.
260 * Verification is the key to maintaining transactional integrity. Because
261 * OVSDB handles multiple clients, it can happen that between the time that
262 * OVSDB client A reads a column and writes a new value, OVSDB client B has
263 * written that column. Client A's write should not ordinarily overwrite
264 * client B's, especially if the column in question is a "map" column that
265 * contains several more or less independent data items. If client A adds a
266 * "verify" operation before it writes the column, then the transaction fails
267 * in case client B modifies it first. Client A will then see the new value of
268 * the column and compose a new transaction based on the new contents written
271 * When a transaction is complete, which must be before the next call to
272 * ovsdb_idl_run() on 'idl', call ovsdb_idl_txn_commit() or
273 * ovsdb_idl_txn_abort().
275 * The life-cycle of a transaction looks like this:
277 * 1. Create the transaction and record the initial sequence number:
279 * seqno = ovsdb_idl_get_seqno(idl);
280 * txn = ovsdb_idl_txn_create(idl);
282 * 2. Modify the database with ovsdb_idl_txn_*() functions directly or
285 * 3. Commit the transaction by calling ovsdb_idl_txn_commit(). The first call
286 * to this function probably returns TXN_INCOMPLETE. The client must keep
287 * calling again along as this remains true, calling ovsdb_idl_run() in
288 * between to let the IDL do protocol processing. (If the client doesn't
289 * have anything else to do in the meantime, it can use
290 * ovsdb_idl_txn_commit_block() to avoid having to loop itself.)
292 * 4. If the final status is TXN_TRY_AGAIN, wait for ovsdb_idl_get_seqno() to
293 * change from the saved 'seqno' (it's possible that it's already changed,
294 * in which case the client should not wait at all), then start over from
295 * step 1. Only a call to ovsdb_idl_run() will change the return value of
296 * ovsdb_idl_get_seqno(). (ovsdb_idl_txn_commit_block() calls
300 enum ovsdb_idl_txn_status
{
301 TXN_UNCOMMITTED
, /* Not yet committed or aborted. */
302 TXN_UNCHANGED
, /* Transaction didn't include any changes. */
303 TXN_INCOMPLETE
, /* Commit in progress, please wait. */
304 TXN_ABORTED
, /* ovsdb_idl_txn_abort() called. */
305 TXN_SUCCESS
, /* Commit successful. */
306 TXN_TRY_AGAIN
, /* Commit failed because a "verify" operation
307 * reported an inconsistency, due to a network
308 * problem, or other transient failure. Wait
309 * for a change, then try again. */
310 TXN_NOT_LOCKED
, /* Server hasn't given us the lock yet. */
311 TXN_ERROR
/* Commit failed due to a hard error. */
314 const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status
);
316 struct ovsdb_idl_txn
*ovsdb_idl_txn_create(struct ovsdb_idl
*);
317 void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn
*, const char *, ...)
318 OVS_PRINTF_FORMAT (2, 3);
319 void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn
*);
320 void ovsdb_idl_txn_increment(struct ovsdb_idl_txn
*,
321 const struct ovsdb_idl_row
*,
322 const struct ovsdb_idl_column
*,
324 void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn
*);
325 void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn
*);
326 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit(struct ovsdb_idl_txn
*);
327 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn
*);
328 void ovsdb_idl_txn_abort(struct ovsdb_idl_txn
*);
330 const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn
*);
332 int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn
*);
333 const struct uuid
*ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn
*,
334 const struct uuid
*);
336 void ovsdb_idl_txn_write(const struct ovsdb_idl_row
*,
337 const struct ovsdb_idl_column
*,
338 struct ovsdb_datum
*);
339 void ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row
*,
340 const struct ovsdb_idl_column
*,
341 const struct ovsdb_datum
*);
342 void ovsdb_idl_txn_write_partial_map(const struct ovsdb_idl_row
*,
343 const struct ovsdb_idl_column
*,
344 struct ovsdb_datum
*);
345 void ovsdb_idl_txn_delete_partial_map(const struct ovsdb_idl_row
*,
346 const struct ovsdb_idl_column
*,
347 struct ovsdb_datum
*);
348 void ovsdb_idl_txn_write_partial_set(const struct ovsdb_idl_row
*,
349 const struct ovsdb_idl_column
*,
350 struct ovsdb_datum
*);
351 void ovsdb_idl_txn_delete_partial_set(const struct ovsdb_idl_row
*,
352 const struct ovsdb_idl_column
*,
353 struct ovsdb_datum
*);
354 void ovsdb_idl_txn_delete(const struct ovsdb_idl_row
*);
355 const struct ovsdb_idl_row
*ovsdb_idl_txn_insert(
356 struct ovsdb_idl_txn
*, const struct ovsdb_idl_table_class
*,
357 const struct uuid
*);
359 struct ovsdb_idl
*ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn
*);
360 void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl
*);
363 /* ovsdb_idl_loop provides an easy way to manage the transactions related
364 * to 'idl' and to cope with different status during transaction. */
365 struct ovsdb_idl_loop
{
366 struct ovsdb_idl
*idl
;
367 unsigned int skip_seqno
;
369 struct ovsdb_idl_txn
*committing_txn
;
370 unsigned int precommit_seqno
;
372 struct ovsdb_idl_txn
*open_txn
;
374 /* These members allow a client a simple, stateless way to keep track of
375 * transactions that commit: when a transaction commits successfully,
376 * ovsdb_idl_loop_commit_and_wait() copies 'next_cfg' to 'cur_cfg'. Thus,
377 * the client can set 'next_cfg' to a value that indicates a successful
378 * commit and check 'cur_cfg' on each iteration. */
383 #define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) }
385 void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop
*);
386 struct ovsdb_idl_txn
*ovsdb_idl_loop_run(struct ovsdb_idl_loop
*);
387 int ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop
*);
389 /* Conditional Replication
390 * =======================
392 * By default, when the IDL replicates a particular table in the database, it
393 * replicates every row in the table. These functions allow the client to
394 * specify that only selected rows should be replicated, by constructing a
395 * per-table condition that specifies the rows to replicate.
397 * A condition is a disjunction of clauses. The condition is true, and thus a
398 * row is replicated, if any of the clauses evaluates to true for a given row.
399 * (Thus, a condition with no clauses is always false.)
402 struct ovsdb_idl_condition
{
403 struct hmap clauses
; /* Contains "struct ovsdb_idl_clause"s. */
404 bool is_true
; /* Is the condition unconditionally true? */
406 #define OVSDB_IDL_CONDITION_INIT(CONDITION) \
407 { HMAP_INITIALIZER(&(CONDITION)->clauses), false }
409 void ovsdb_idl_condition_init(struct ovsdb_idl_condition
*);
410 void ovsdb_idl_condition_clear(struct ovsdb_idl_condition
*);
411 void ovsdb_idl_condition_destroy(struct ovsdb_idl_condition
*);
412 void ovsdb_idl_condition_add_clause(struct ovsdb_idl_condition
*,
413 enum ovsdb_function function
,
414 const struct ovsdb_idl_column
*column
,
415 const struct ovsdb_datum
*arg
);
416 void ovsdb_idl_condition_add_clause_true(struct ovsdb_idl_condition
*);
417 bool ovsdb_idl_condition_is_true(const struct ovsdb_idl_condition
*);
419 unsigned int ovsdb_idl_set_condition(struct ovsdb_idl
*,
420 const struct ovsdb_idl_table_class
*,
421 const struct ovsdb_idl_condition
*);
423 unsigned int ovsdb_idl_get_condition_seqno(const struct ovsdb_idl
*);
425 /* Indexes over one or more columns in the IDL, to retrieve rows matching
426 * particular search criteria and to iterate over a subset of rows in a defined
429 enum ovsdb_index_order
{
430 OVSDB_INDEX_ASC
, /* 0, 1, 2, ... */
431 OVSDB_INDEX_DESC
/* 2, 1, 0, ... */
434 typedef int column_comparator_func(const void *a
, const void *b
);
436 struct ovsdb_idl_index_column
{
437 const struct ovsdb_idl_column
*column
;
438 column_comparator_func
*comparer
;
439 enum ovsdb_index_order order
;
442 /* Creating an index. */
443 struct ovsdb_idl_index
*ovsdb_idl_index_create(
444 struct ovsdb_idl
*, const struct ovsdb_idl_index_column
*, size_t n
);
445 struct ovsdb_idl_index
*ovsdb_idl_index_create1(
446 struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
447 struct ovsdb_idl_index
*ovsdb_idl_index_create2(
448 struct ovsdb_idl
*, const struct ovsdb_idl_column
*,
449 const struct ovsdb_idl_column
*);
451 /* Searching an index. */
452 struct ovsdb_idl_row
*ovsdb_idl_index_find(struct ovsdb_idl_index
*,
453 const struct ovsdb_idl_row
*);
455 /* Iteration over an index.
457 * Usually these would be invoked through table-specific wrappers generated
460 struct ovsdb_idl_cursor
{
461 struct ovsdb_idl_index
*index
; /* Index being iterated. */
462 struct skiplist_node
*position
; /* Current position in 'index'. */
465 struct ovsdb_idl_cursor
ovsdb_idl_cursor_first(struct ovsdb_idl_index
*);
466 struct ovsdb_idl_cursor
ovsdb_idl_cursor_first_eq(
467 struct ovsdb_idl_index
*, const struct ovsdb_idl_row
*);
468 struct ovsdb_idl_cursor
ovsdb_idl_cursor_first_ge(
469 struct ovsdb_idl_index
*, const struct ovsdb_idl_row
*);
471 void ovsdb_idl_cursor_next(struct ovsdb_idl_cursor
*);
472 void ovsdb_idl_cursor_next_eq(struct ovsdb_idl_cursor
*);
474 struct ovsdb_idl_row
*ovsdb_idl_cursor_data(struct ovsdb_idl_cursor
*);
480 #endif /* ovsdb-idl.h */