1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Nicira, Inc.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
19 /* Open vSwitch Database Interface Definition Language (OVSDB IDL).
21 * The OVSDB IDL maintains an in-memory replica of a database. It issues RPC
22 * requests to an OVSDB database server and parses the responses, converting
23 * raw JSON into data structures that are easier for clients to digest. Most
24 * notably, references to rows via UUID become C pointers.
26 * The IDL always presents a consistent snapshot of the database to its client,
27 * that is, it won't present the effects of some part of a transaction applied
28 * at the database server without presenting all of its effects.
30 * The IDL also assists with issuing database transactions. The client creates
31 * a transaction, manipulates the IDL data structures, and commits or aborts
32 * the transaction. The IDL then composes and issues the necessary JSON-RPC
33 * requests and reports to the client whether the transaction completed
40 #include "ovsdb-types.h"
41 #include "ovsdb-data.h"
42 #include "openvswitch/list.h"
43 #include "ovsdb-condition.h"
47 struct ovsdb_idl_class
;
49 struct ovsdb_idl_column
;
50 struct ovsdb_idl_table_class
;
53 struct ovsdb_idl
*ovsdb_idl_create(const char *remote
,
54 const struct ovsdb_idl_class
*,
55 bool monitor_everything_by_default
,
57 void ovsdb_idl_set_remote(struct ovsdb_idl
*, const char *, bool);
58 void ovsdb_idl_destroy(struct ovsdb_idl
*);
60 void ovsdb_idl_run(struct ovsdb_idl
*);
61 void ovsdb_idl_wait(struct ovsdb_idl
*);
63 void ovsdb_idl_set_lock(struct ovsdb_idl
*, const char *lock_name
);
64 bool ovsdb_idl_has_lock(const struct ovsdb_idl
*);
65 bool ovsdb_idl_is_lock_contended(const struct ovsdb_idl
*);
67 const struct uuid
* ovsdb_idl_get_monitor_id(const struct ovsdb_idl
*);
68 unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl
*);
69 bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl
*);
70 void ovsdb_idl_enable_reconnect(struct ovsdb_idl
*);
71 void ovsdb_idl_force_reconnect(struct ovsdb_idl
*);
72 void ovsdb_idl_verify_write_only(struct ovsdb_idl
*);
74 bool ovsdb_idl_is_alive(const struct ovsdb_idl
*);
75 int ovsdb_idl_get_last_error(const struct ovsdb_idl
*);
77 void ovsdb_idl_set_probe_interval(const struct ovsdb_idl
*, int probe_interval
);
79 void ovsdb_idl_check_consistency(const struct ovsdb_idl
*);
81 const struct ovsdb_idl_class
*ovsdb_idl_get_class(const struct ovsdb_idl
*);
82 const struct ovsdb_idl_table_class
*ovsdb_idl_table_class_from_column(
83 const struct ovsdb_idl_class
*, const struct ovsdb_idl_column
*);
85 /* Choosing columns and tables to replicate. */
87 /* Modes with which the IDL can monitor a column.
89 * If no bits are set, the column is not monitored at all. Its value will
90 * always appear to the client to be the default value for its type.
92 * If OVSDB_IDL_MONITOR is set, then the column is replicated. Its value will
93 * reflect the value in the database. If OVSDB_IDL_ALERT is also set, then the
94 * value returned by ovsdb_idl_get_seqno() will change when the column's value
97 * The possible mode combinations are:
99 * - 0, for a column that a client doesn't care about.
101 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants
102 * to track and possibly update.
104 * - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only",
105 * that is, it updates them but doesn't want to get alerted about its own
106 * updates. It also won't be alerted about other clients' updates, so this
107 * is suitable only for use by a client that "owns" a particular column.
109 * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid.
111 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT | OVSDB_IDL_TRACK), for a column
112 * that a client wants to track using the change tracking
113 * ovsdb_idl_track_get_*() functions.
115 #define OVSDB_IDL_MONITOR (1 << 0) /* Monitor this column? */
116 #define OVSDB_IDL_ALERT (1 << 1) /* Alert client when column updated? */
117 #define OVSDB_IDL_TRACK (1 << 2)
119 void ovsdb_idl_add_column(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
120 void ovsdb_idl_add_table(struct ovsdb_idl
*,
121 const struct ovsdb_idl_table_class
*);
123 void ovsdb_idl_omit(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
124 void ovsdb_idl_omit_alert(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
128 * In OVSDB, change tracking is applied at each client in the IDL layer. This
129 * means that when a client makes a request to track changes on a particular
130 * table, they are essentially requesting information about the incremental
131 * changes to that table from the point in time that the request is made. Once
132 * the client clears tracked changes, that information will no longer be
135 * The implication of the above is that if a client requires replaying
136 * untracked history, it faces the choice of either trying to remember changes
137 * itself (which translates into a memory leak) or of being structured with a
138 * path for processing the full untracked table as well as a path that
139 * processes incremental changes. */
140 enum ovsdb_idl_change
{
141 OVSDB_IDL_CHANGE_INSERT
,
142 OVSDB_IDL_CHANGE_MODIFY
,
143 OVSDB_IDL_CHANGE_DELETE
,
147 /* Row, table sequence numbers */
148 unsigned int ovsdb_idl_table_get_seqno(
149 const struct ovsdb_idl
*idl
,
150 const struct ovsdb_idl_table_class
*table_class
);
151 unsigned int ovsdb_idl_row_get_seqno(
152 const struct ovsdb_idl_row
*row
,
153 enum ovsdb_idl_change change
);
155 void ovsdb_idl_track_add_column(struct ovsdb_idl
*idl
,
156 const struct ovsdb_idl_column
*column
);
157 void ovsdb_idl_track_add_all(struct ovsdb_idl
*idl
);
158 const struct ovsdb_idl_row
*ovsdb_idl_track_get_first(
159 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
160 const struct ovsdb_idl_row
*ovsdb_idl_track_get_next(const struct ovsdb_idl_row
*);
161 bool ovsdb_idl_track_is_updated(const struct ovsdb_idl_row
*row
,
162 const struct ovsdb_idl_column
*column
);
163 void ovsdb_idl_track_clear(const struct ovsdb_idl
*);
166 /* Reading the database replica. */
168 const struct ovsdb_idl_row
*ovsdb_idl_get_row_for_uuid(
169 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*,
170 const struct uuid
*);
171 const struct ovsdb_idl_row
*ovsdb_idl_first_row(
172 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
173 const struct ovsdb_idl_row
*ovsdb_idl_next_row(const struct ovsdb_idl_row
*);
175 const struct ovsdb_datum
*ovsdb_idl_read(const struct ovsdb_idl_row
*,
176 const struct ovsdb_idl_column
*);
177 const struct ovsdb_datum
*ovsdb_idl_get(const struct ovsdb_idl_row
*,
178 const struct ovsdb_idl_column
*,
179 enum ovsdb_atomic_type key_type
,
180 enum ovsdb_atomic_type value_type
);
181 bool ovsdb_idl_is_mutable(const struct ovsdb_idl_row
*,
182 const struct ovsdb_idl_column
*);
184 bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row
*);
188 * A transaction may modify the contents of a database by modifying the values
189 * of columns, deleting rows, inserting rows, or adding checks that columns in
190 * the database have not changed ("verify" operations), through
191 * ovsdb_idl_txn_*() functions. (The OVSDB IDL code generator produces helper
192 * functions that internally call the ovsdb_idl_txn_*() functions. These are
193 * likely to be more convenient.)
195 * Reading and writing columns and inserting and deleting rows are all
196 * straightforward. The reasons to verify columns are less obvious.
197 * Verification is the key to maintaining transactional integrity. Because
198 * OVSDB handles multiple clients, it can happen that between the time that
199 * OVSDB client A reads a column and writes a new value, OVSDB client B has
200 * written that column. Client A's write should not ordinarily overwrite
201 * client B's, especially if the column in question is a "map" column that
202 * contains several more or less independent data items. If client A adds a
203 * "verify" operation before it writes the column, then the transaction fails
204 * in case client B modifies it first. Client A will then see the new value of
205 * the column and compose a new transaction based on the new contents written
208 * When a transaction is complete, which must be before the next call to
209 * ovsdb_idl_run() on 'idl', call ovsdb_idl_txn_commit() or
210 * ovsdb_idl_txn_abort().
212 * The life-cycle of a transaction looks like this:
214 * 1. Create the transaction and record the initial sequence number:
216 * seqno = ovsdb_idl_get_seqno(idl);
217 * txn = ovsdb_idl_txn_create(idl);
219 * 2. Modify the database with ovsdb_idl_txn_*() functions directly or
222 * 3. Commit the transaction by calling ovsdb_idl_txn_commit(). The first call
223 * to this function probably returns TXN_INCOMPLETE. The client must keep
224 * calling again along as this remains true, calling ovsdb_idl_run() in
225 * between to let the IDL do protocol processing. (If the client doesn't
226 * have anything else to do in the meantime, it can use
227 * ovsdb_idl_txn_commit_block() to avoid having to loop itself.)
229 * 4. If the final status is TXN_TRY_AGAIN, wait for ovsdb_idl_get_seqno() to
230 * change from the saved 'seqno' (it's possible that it's already changed,
231 * in which case the client should not wait at all), then start over from
232 * step 1. Only a call to ovsdb_idl_run() will change the return value of
233 * ovsdb_idl_get_seqno(). (ovsdb_idl_txn_commit_block() calls
237 enum ovsdb_idl_txn_status
{
238 TXN_UNCOMMITTED
, /* Not yet committed or aborted. */
239 TXN_UNCHANGED
, /* Transaction didn't include any changes. */
240 TXN_INCOMPLETE
, /* Commit in progress, please wait. */
241 TXN_ABORTED
, /* ovsdb_idl_txn_abort() called. */
242 TXN_SUCCESS
, /* Commit successful. */
243 TXN_TRY_AGAIN
, /* Commit failed because a "verify" operation
244 * reported an inconsistency, due to a network
245 * problem, or other transient failure. Wait
246 * for a change, then try again. */
247 TXN_NOT_LOCKED
, /* Server hasn't given us the lock yet. */
248 TXN_ERROR
/* Commit failed due to a hard error. */
251 const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status
);
253 struct ovsdb_idl_txn
*ovsdb_idl_txn_create(struct ovsdb_idl
*);
254 void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn
*, const char *, ...)
255 OVS_PRINTF_FORMAT (2, 3);
256 void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn
*);
257 void ovsdb_idl_txn_increment(struct ovsdb_idl_txn
*,
258 const struct ovsdb_idl_row
*,
259 const struct ovsdb_idl_column
*,
261 void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn
*);
262 void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn
*);
263 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit(struct ovsdb_idl_txn
*);
264 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn
*);
265 void ovsdb_idl_txn_abort(struct ovsdb_idl_txn
*);
267 const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn
*);
269 int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn
*);
270 const struct uuid
*ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn
*,
271 const struct uuid
*);
273 void ovsdb_idl_txn_write(const struct ovsdb_idl_row
*,
274 const struct ovsdb_idl_column
*,
275 struct ovsdb_datum
*);
276 void ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row
*,
277 const struct ovsdb_idl_column
*,
278 const struct ovsdb_datum
*);
279 void ovsdb_idl_txn_write_partial_map(const struct ovsdb_idl_row
*,
280 const struct ovsdb_idl_column
*,
281 struct ovsdb_datum
*);
282 void ovsdb_idl_txn_delete_partial_map(const struct ovsdb_idl_row
*,
283 const struct ovsdb_idl_column
*,
284 struct ovsdb_datum
*);
285 void ovsdb_idl_txn_write_partial_set(const struct ovsdb_idl_row
*,
286 const struct ovsdb_idl_column
*,
287 struct ovsdb_datum
*);
288 void ovsdb_idl_txn_delete_partial_set(const struct ovsdb_idl_row
*,
289 const struct ovsdb_idl_column
*,
290 struct ovsdb_datum
*);
291 void ovsdb_idl_txn_delete(const struct ovsdb_idl_row
*);
292 const struct ovsdb_idl_row
*ovsdb_idl_txn_insert(
293 struct ovsdb_idl_txn
*, const struct ovsdb_idl_table_class
*,
294 const struct uuid
*);
296 struct ovsdb_idl
*ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn
*);
297 void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl
*);
300 /* ovsdb_idl_loop provides an easy way to manage the transactions related
301 * to 'idl' and to cope with different status during transaction. */
302 struct ovsdb_idl_loop
{
303 struct ovsdb_idl
*idl
;
304 unsigned int skip_seqno
;
306 struct ovsdb_idl_txn
*committing_txn
;
307 unsigned int precommit_seqno
;
309 struct ovsdb_idl_txn
*open_txn
;
311 /* These members allow a client a simple, stateless way to keep track of
312 * transactions that commit: when a transaction commits successfully,
313 * ovsdb_idl_loop_commit_and_wait() copies 'next_cfg' to 'cur_cfg'. Thus,
314 * the client can set 'next_cfg' to a value that indicates a successful
315 * commit and check 'cur_cfg' on each iteration. */
320 #define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) }
322 void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop
*);
323 struct ovsdb_idl_txn
*ovsdb_idl_loop_run(struct ovsdb_idl_loop
*);
324 int ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop
*);
326 /* Conditional Replication
327 * =======================
329 * By default, when the IDL replicates a particular table in the database, it
330 * replicates every row in the table. These functions allow the client to
331 * specify that only selected rows should be replicated, by constructing a
332 * per-table condition that specifies the rows to replicate.
334 * A condition is a disjunction of clauses. The condition is true, and thus a
335 * row is replicated, if any of the clauses evaluates to true for a given row.
336 * (Thus, a condition with no clauses is always false.)
339 struct ovsdb_idl_condition
{
340 struct hmap clauses
; /* Contains "struct ovsdb_idl_clause"s. */
341 bool is_true
; /* Is the condition unconditionally true? */
343 #define OVSDB_IDL_CONDITION_INIT(CONDITION) \
344 { HMAP_INITIALIZER(&(CONDITION)->clauses), false }
346 void ovsdb_idl_condition_init(struct ovsdb_idl_condition
*);
347 void ovsdb_idl_condition_clear(struct ovsdb_idl_condition
*);
348 void ovsdb_idl_condition_destroy(struct ovsdb_idl_condition
*);
349 void ovsdb_idl_condition_add_clause(struct ovsdb_idl_condition
*,
350 enum ovsdb_function function
,
351 const struct ovsdb_idl_column
*column
,
352 const struct ovsdb_datum
*arg
);
353 void ovsdb_idl_condition_add_clause_true(struct ovsdb_idl_condition
*);
354 bool ovsdb_idl_condition_is_true(const struct ovsdb_idl_condition
*);
356 unsigned int ovsdb_idl_set_condition(struct ovsdb_idl
*,
357 const struct ovsdb_idl_table_class
*,
358 const struct ovsdb_idl_condition
*);
360 unsigned int ovsdb_idl_get_condition_seqno(const struct ovsdb_idl
*);
361 #endif /* ovsdb-idl.h */