1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 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_destroy(struct ovsdb_idl
*);
69 void ovsdb_idl_set_leader_only(struct ovsdb_idl
*, bool leader_only
);
71 void ovsdb_idl_run(struct ovsdb_idl
*);
72 void ovsdb_idl_wait(struct ovsdb_idl
*);
74 void ovsdb_idl_set_lock(struct ovsdb_idl
*, const char *lock_name
);
75 bool ovsdb_idl_has_lock(const struct ovsdb_idl
*);
76 bool ovsdb_idl_is_lock_contended(const struct ovsdb_idl
*);
78 const struct uuid
* ovsdb_idl_get_monitor_id(const struct ovsdb_idl
*);
79 unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl
*);
80 bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl
*);
81 void ovsdb_idl_enable_reconnect(struct ovsdb_idl
*);
82 void ovsdb_idl_force_reconnect(struct ovsdb_idl
*);
83 void ovsdb_idl_verify_write_only(struct ovsdb_idl
*);
85 bool ovsdb_idl_is_alive(const struct ovsdb_idl
*);
86 bool ovsdb_idl_is_connected(const struct ovsdb_idl
*idl
);
87 int ovsdb_idl_get_last_error(const struct ovsdb_idl
*);
89 void ovsdb_idl_set_probe_interval(const struct ovsdb_idl
*, int probe_interval
);
91 void ovsdb_idl_check_consistency(const struct ovsdb_idl
*);
93 const struct ovsdb_idl_class
*ovsdb_idl_get_class(const struct ovsdb_idl
*);
94 const struct ovsdb_idl_table_class
*ovsdb_idl_table_class_from_column(
95 const struct ovsdb_idl_class
*, const struct ovsdb_idl_column
*);
97 /* Choosing columns and tables to replicate. */
99 /* Modes with which the IDL can monitor a column.
101 * If no bits are set, the column is not monitored at all. Its value will
102 * always appear to the client to be the default value for its type.
104 * If OVSDB_IDL_MONITOR is set, then the column is replicated. Its value will
105 * reflect the value in the database. If OVSDB_IDL_ALERT is also set, then the
106 * value returned by ovsdb_idl_get_seqno() will change when the column's value
109 * The possible mode combinations are:
111 * - 0, for a column that a client doesn't care about.
113 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants
114 * to track and possibly update.
116 * - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only",
117 * that is, it updates them but doesn't want to get alerted about its own
118 * updates. It also won't be alerted about other clients' updates, so this
119 * is suitable only for use by a client that "owns" a particular column.
121 * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid.
123 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT | OVSDB_IDL_TRACK), for a column
124 * that a client wants to track using the change tracking
125 * ovsdb_idl_track_get_*() functions.
127 #define OVSDB_IDL_MONITOR (1 << 0) /* Monitor this column? */
128 #define OVSDB_IDL_ALERT (1 << 1) /* Alert client when column updated? */
129 #define OVSDB_IDL_TRACK (1 << 2)
131 void ovsdb_idl_add_column(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
132 void ovsdb_idl_add_table(struct ovsdb_idl
*,
133 const struct ovsdb_idl_table_class
*);
135 void ovsdb_idl_omit(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
136 void ovsdb_idl_omit_alert(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
140 * In OVSDB, change tracking is applied at each client in the IDL layer. This
141 * means that when a client makes a request to track changes on a particular
142 * table, they are essentially requesting information about the incremental
143 * changes to that table from the point in time that the request is made. Once
144 * the client clears tracked changes, that information will no longer be
147 * The implication of the above is that if a client requires replaying
148 * untracked history, it faces the choice of either trying to remember changes
149 * itself (which translates into a memory leak) or of being structured with a
150 * path for processing the full untracked table as well as a path that
151 * processes incremental changes. */
152 enum ovsdb_idl_change
{
153 OVSDB_IDL_CHANGE_INSERT
,
154 OVSDB_IDL_CHANGE_MODIFY
,
155 OVSDB_IDL_CHANGE_DELETE
,
159 /* Row, table sequence numbers */
160 unsigned int ovsdb_idl_table_get_seqno(
161 const struct ovsdb_idl
*idl
,
162 const struct ovsdb_idl_table_class
*table_class
);
163 unsigned int ovsdb_idl_row_get_seqno(
164 const struct ovsdb_idl_row
*row
,
165 enum ovsdb_idl_change change
);
167 void ovsdb_idl_track_add_column(struct ovsdb_idl
*idl
,
168 const struct ovsdb_idl_column
*column
);
169 void ovsdb_idl_track_add_all(struct ovsdb_idl
*idl
);
170 const struct ovsdb_idl_row
*ovsdb_idl_track_get_first(
171 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
172 const struct ovsdb_idl_row
*ovsdb_idl_track_get_next(const struct ovsdb_idl_row
*);
173 bool ovsdb_idl_track_is_updated(const struct ovsdb_idl_row
*row
,
174 const struct ovsdb_idl_column
*column
);
175 void ovsdb_idl_track_clear(struct ovsdb_idl
*);
178 /* Reading the database replica. */
180 const struct ovsdb_idl_row
*ovsdb_idl_get_row_for_uuid(
181 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*,
182 const struct uuid
*);
183 const struct ovsdb_idl_row
*ovsdb_idl_first_row(
184 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
185 const struct ovsdb_idl_row
*ovsdb_idl_next_row(const struct ovsdb_idl_row
*);
187 const struct ovsdb_datum
*ovsdb_idl_read(const struct ovsdb_idl_row
*,
188 const struct ovsdb_idl_column
*);
189 const struct ovsdb_datum
*ovsdb_idl_get(const struct ovsdb_idl_row
*,
190 const struct ovsdb_idl_column
*,
191 enum ovsdb_atomic_type key_type
,
192 enum ovsdb_atomic_type value_type
);
193 bool ovsdb_idl_is_mutable(const struct ovsdb_idl_row
*,
194 const struct ovsdb_idl_column
*);
196 bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row
*);
200 * A transaction may modify the contents of a database by modifying the values
201 * of columns, deleting rows, inserting rows, or adding checks that columns in
202 * the database have not changed ("verify" operations), through
203 * ovsdb_idl_txn_*() functions. (The OVSDB IDL code generator produces helper
204 * functions that internally call the ovsdb_idl_txn_*() functions. These are
205 * likely to be more convenient.)
207 * Reading and writing columns and inserting and deleting rows are all
208 * straightforward. The reasons to verify columns are less obvious.
209 * Verification is the key to maintaining transactional integrity. Because
210 * OVSDB handles multiple clients, it can happen that between the time that
211 * OVSDB client A reads a column and writes a new value, OVSDB client B has
212 * written that column. Client A's write should not ordinarily overwrite
213 * client B's, especially if the column in question is a "map" column that
214 * contains several more or less independent data items. If client A adds a
215 * "verify" operation before it writes the column, then the transaction fails
216 * in case client B modifies it first. Client A will then see the new value of
217 * the column and compose a new transaction based on the new contents written
220 * When a transaction is complete, which must be before the next call to
221 * ovsdb_idl_run() on 'idl', call ovsdb_idl_txn_commit() or
222 * ovsdb_idl_txn_abort().
224 * The life-cycle of a transaction looks like this:
226 * 1. Create the transaction and record the initial sequence number:
228 * seqno = ovsdb_idl_get_seqno(idl);
229 * txn = ovsdb_idl_txn_create(idl);
231 * 2. Modify the database with ovsdb_idl_txn_*() functions directly or
234 * 3. Commit the transaction by calling ovsdb_idl_txn_commit(). The first call
235 * to this function probably returns TXN_INCOMPLETE. The client must keep
236 * calling again along as this remains true, calling ovsdb_idl_run() in
237 * between to let the IDL do protocol processing. (If the client doesn't
238 * have anything else to do in the meantime, it can use
239 * ovsdb_idl_txn_commit_block() to avoid having to loop itself.)
241 * 4. If the final status is TXN_TRY_AGAIN, wait for ovsdb_idl_get_seqno() to
242 * change from the saved 'seqno' (it's possible that it's already changed,
243 * in which case the client should not wait at all), then start over from
244 * step 1. Only a call to ovsdb_idl_run() will change the return value of
245 * ovsdb_idl_get_seqno(). (ovsdb_idl_txn_commit_block() calls
249 enum ovsdb_idl_txn_status
{
250 TXN_UNCOMMITTED
, /* Not yet committed or aborted. */
251 TXN_UNCHANGED
, /* Transaction didn't include any changes. */
252 TXN_INCOMPLETE
, /* Commit in progress, please wait. */
253 TXN_ABORTED
, /* ovsdb_idl_txn_abort() called. */
254 TXN_SUCCESS
, /* Commit successful. */
255 TXN_TRY_AGAIN
, /* Commit failed because a "verify" operation
256 * reported an inconsistency, due to a network
257 * problem, or other transient failure. Wait
258 * for a change, then try again. */
259 TXN_NOT_LOCKED
, /* Server hasn't given us the lock yet. */
260 TXN_ERROR
/* Commit failed due to a hard error. */
263 const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status
);
265 struct ovsdb_idl_txn
*ovsdb_idl_txn_create(struct ovsdb_idl
*);
266 void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn
*, const char *, ...)
267 OVS_PRINTF_FORMAT (2, 3);
268 void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn
*);
269 void ovsdb_idl_txn_increment(struct ovsdb_idl_txn
*,
270 const struct ovsdb_idl_row
*,
271 const struct ovsdb_idl_column
*,
273 void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn
*);
274 void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn
*);
275 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit(struct ovsdb_idl_txn
*);
276 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn
*);
277 void ovsdb_idl_txn_abort(struct ovsdb_idl_txn
*);
279 const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn
*);
281 int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn
*);
282 const struct uuid
*ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn
*,
283 const struct uuid
*);
285 void ovsdb_idl_txn_write(const struct ovsdb_idl_row
*,
286 const struct ovsdb_idl_column
*,
287 struct ovsdb_datum
*);
288 void ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row
*,
289 const struct ovsdb_idl_column
*,
290 const struct ovsdb_datum
*);
291 void ovsdb_idl_txn_write_partial_map(const struct ovsdb_idl_row
*,
292 const struct ovsdb_idl_column
*,
293 struct ovsdb_datum
*);
294 void ovsdb_idl_txn_delete_partial_map(const struct ovsdb_idl_row
*,
295 const struct ovsdb_idl_column
*,
296 struct ovsdb_datum
*);
297 void ovsdb_idl_txn_write_partial_set(const struct ovsdb_idl_row
*,
298 const struct ovsdb_idl_column
*,
299 struct ovsdb_datum
*);
300 void ovsdb_idl_txn_delete_partial_set(const struct ovsdb_idl_row
*,
301 const struct ovsdb_idl_column
*,
302 struct ovsdb_datum
*);
303 void ovsdb_idl_txn_delete(const struct ovsdb_idl_row
*);
304 const struct ovsdb_idl_row
*ovsdb_idl_txn_insert(
305 struct ovsdb_idl_txn
*, const struct ovsdb_idl_table_class
*,
306 const struct uuid
*);
308 struct ovsdb_idl
*ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn
*);
309 void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl
*);
312 /* ovsdb_idl_loop provides an easy way to manage the transactions related
313 * to 'idl' and to cope with different status during transaction. */
314 struct ovsdb_idl_loop
{
315 struct ovsdb_idl
*idl
;
316 unsigned int skip_seqno
;
318 struct ovsdb_idl_txn
*committing_txn
;
319 unsigned int precommit_seqno
;
321 struct ovsdb_idl_txn
*open_txn
;
323 /* These members allow a client a simple, stateless way to keep track of
324 * transactions that commit: when a transaction commits successfully,
325 * ovsdb_idl_loop_commit_and_wait() copies 'next_cfg' to 'cur_cfg'. Thus,
326 * the client can set 'next_cfg' to a value that indicates a successful
327 * commit and check 'cur_cfg' on each iteration. */
332 #define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) }
334 void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop
*);
335 struct ovsdb_idl_txn
*ovsdb_idl_loop_run(struct ovsdb_idl_loop
*);
336 int ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop
*);
338 /* Conditional Replication
339 * =======================
341 * By default, when the IDL replicates a particular table in the database, it
342 * replicates every row in the table. These functions allow the client to
343 * specify that only selected rows should be replicated, by constructing a
344 * per-table condition that specifies the rows to replicate.
346 * A condition is a disjunction of clauses. The condition is true, and thus a
347 * row is replicated, if any of the clauses evaluates to true for a given row.
348 * (Thus, a condition with no clauses is always false.)
351 struct ovsdb_idl_condition
{
352 struct hmap clauses
; /* Contains "struct ovsdb_idl_clause"s. */
353 bool is_true
; /* Is the condition unconditionally true? */
355 #define OVSDB_IDL_CONDITION_INIT(CONDITION) \
356 { HMAP_INITIALIZER(&(CONDITION)->clauses), false }
358 void ovsdb_idl_condition_init(struct ovsdb_idl_condition
*);
359 void ovsdb_idl_condition_clear(struct ovsdb_idl_condition
*);
360 void ovsdb_idl_condition_destroy(struct ovsdb_idl_condition
*);
361 void ovsdb_idl_condition_add_clause(struct ovsdb_idl_condition
*,
362 enum ovsdb_function function
,
363 const struct ovsdb_idl_column
*column
,
364 const struct ovsdb_datum
*arg
);
365 void ovsdb_idl_condition_add_clause_true(struct ovsdb_idl_condition
*);
366 bool ovsdb_idl_condition_is_true(const struct ovsdb_idl_condition
*);
368 unsigned int ovsdb_idl_set_condition(struct ovsdb_idl
*,
369 const struct ovsdb_idl_table_class
*,
370 const struct ovsdb_idl_condition
*);
372 unsigned int ovsdb_idl_get_condition_seqno(const struct ovsdb_idl
*);
374 /* Indexes over one or more columns in the IDL, to retrieve rows matching
375 * particular search criteria and to iterate over a subset of rows in a defined
378 enum ovsdb_index_order
{
379 OVSDB_INDEX_ASC
, /* 0, 1, 2, ... */
380 OVSDB_INDEX_DESC
/* 2, 1, 0, ... */
383 typedef int column_comparator_func(const void *a
, const void *b
);
385 struct ovsdb_idl_index_column
{
386 const struct ovsdb_idl_column
*column
;
387 column_comparator_func
*comparer
;
388 enum ovsdb_index_order order
;
391 /* Creating an index. */
392 struct ovsdb_idl_index
*ovsdb_idl_index_create(
393 struct ovsdb_idl
*, const struct ovsdb_idl_index_column
*, size_t n
);
394 struct ovsdb_idl_index
*ovsdb_idl_index_create1(
395 struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
396 struct ovsdb_idl_index
*ovsdb_idl_index_create2(
397 struct ovsdb_idl
*, const struct ovsdb_idl_column
*,
398 const struct ovsdb_idl_column
*);
400 /* Searching an index. */
401 struct ovsdb_idl_row
*ovsdb_idl_index_find(struct ovsdb_idl_index
*,
402 const struct ovsdb_idl_row
*);
404 /* Iteration over an index.
406 * Usually these would be invoked through table-specific wrappers generated
409 struct ovsdb_idl_cursor
{
410 struct ovsdb_idl_index
*index
; /* Index being iterated. */
411 struct skiplist_node
*position
; /* Current position in 'index'. */
414 struct ovsdb_idl_cursor
ovsdb_idl_cursor_first(struct ovsdb_idl_index
*);
415 struct ovsdb_idl_cursor
ovsdb_idl_cursor_first_eq(
416 struct ovsdb_idl_index
*, const struct ovsdb_idl_row
*);
417 struct ovsdb_idl_cursor
ovsdb_idl_cursor_first_ge(
418 struct ovsdb_idl_index
*, const struct ovsdb_idl_row
*);
420 void ovsdb_idl_cursor_next(struct ovsdb_idl_cursor
*);
421 void ovsdb_idl_cursor_next_eq(struct ovsdb_idl_cursor
*);
423 struct ovsdb_idl_row
*ovsdb_idl_cursor_data(struct ovsdb_idl_cursor
*);
429 #endif /* ovsdb-idl.h */