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 /* Choosing columns and tables to replicate. */
83 /* Modes with which the IDL can monitor a column.
85 * If no bits are set, the column is not monitored at all. Its value will
86 * always appear to the client to be the default value for its type.
88 * If OVSDB_IDL_MONITOR is set, then the column is replicated. Its value will
89 * reflect the value in the database. If OVSDB_IDL_ALERT is also set, then the
90 * value returned by ovsdb_idl_get_seqno() will change when the column's value
93 * The possible mode combinations are:
95 * - 0, for a column that a client doesn't care about.
97 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants
98 * to track and possibly update.
100 * - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only",
101 * that is, it updates them but doesn't want to get alerted about its own
102 * updates. It also won't be alerted about other clients' updates, so this
103 * is suitable only for use by a client that "owns" a particular column.
105 * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid.
107 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT | OVSDB_IDL_TRACK), for a column
108 * that a client wants to track using the change tracking
109 * ovsdb_idl_track_get_*() functions.
111 #define OVSDB_IDL_MONITOR (1 << 0) /* Monitor this column? */
112 #define OVSDB_IDL_ALERT (1 << 1) /* Alert client when column updated? */
113 #define OVSDB_IDL_TRACK (1 << 2)
115 void ovsdb_idl_add_column(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
116 void ovsdb_idl_add_table(struct ovsdb_idl
*,
117 const struct ovsdb_idl_table_class
*);
119 void ovsdb_idl_omit(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
120 void ovsdb_idl_omit_alert(struct ovsdb_idl
*, const struct ovsdb_idl_column
*);
124 * In OVSDB, change tracking is applied at each client in the IDL layer. This
125 * means that when a client makes a request to track changes on a particular
126 * table, they are essentially requesting information about the incremental
127 * changes to that table from the point in time that the request is made. Once
128 * the client clears tracked changes, that information will no longer be
131 * The implication of the above is that if a client requires replaying
132 * untracked history, it faces the choice of either trying to remember changes
133 * itself (which translates into a memory leak) or of being structured with a
134 * path for processing the full untracked table as well as a path that
135 * processes incremental changes. */
136 enum ovsdb_idl_change
{
137 OVSDB_IDL_CHANGE_INSERT
,
138 OVSDB_IDL_CHANGE_MODIFY
,
139 OVSDB_IDL_CHANGE_DELETE
,
143 /* Row, table sequence numbers */
144 unsigned int ovsdb_idl_table_get_seqno(
145 const struct ovsdb_idl
*idl
,
146 const struct ovsdb_idl_table_class
*table_class
);
147 unsigned int ovsdb_idl_row_get_seqno(
148 const struct ovsdb_idl_row
*row
,
149 enum ovsdb_idl_change change
);
151 void ovsdb_idl_track_add_column(struct ovsdb_idl
*idl
,
152 const struct ovsdb_idl_column
*column
);
153 void ovsdb_idl_track_add_all(struct ovsdb_idl
*idl
);
154 const struct ovsdb_idl_row
*ovsdb_idl_track_get_first(
155 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
156 const struct ovsdb_idl_row
*ovsdb_idl_track_get_next(const struct ovsdb_idl_row
*);
157 bool ovsdb_idl_track_is_updated(const struct ovsdb_idl_row
*row
,
158 const struct ovsdb_idl_column
*column
);
159 void ovsdb_idl_track_clear(const struct ovsdb_idl
*);
162 /* Reading the database replica. */
164 const struct ovsdb_idl_row
*ovsdb_idl_get_row_for_uuid(
165 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*,
166 const struct uuid
*);
167 const struct ovsdb_idl_row
*ovsdb_idl_first_row(
168 const struct ovsdb_idl
*, const struct ovsdb_idl_table_class
*);
169 const struct ovsdb_idl_row
*ovsdb_idl_next_row(const struct ovsdb_idl_row
*);
171 const struct ovsdb_datum
*ovsdb_idl_read(const struct ovsdb_idl_row
*,
172 const struct ovsdb_idl_column
*);
173 const struct ovsdb_datum
*ovsdb_idl_get(const struct ovsdb_idl_row
*,
174 const struct ovsdb_idl_column
*,
175 enum ovsdb_atomic_type key_type
,
176 enum ovsdb_atomic_type value_type
);
177 bool ovsdb_idl_is_mutable(const struct ovsdb_idl_row
*,
178 const struct ovsdb_idl_column
*);
180 bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row
*);
184 * A transaction may modify the contents of a database by modifying the values
185 * of columns, deleting rows, inserting rows, or adding checks that columns in
186 * the database have not changed ("verify" operations), through
187 * ovsdb_idl_txn_*() functions. (The OVSDB IDL code generator produces helper
188 * functions that internally call the ovsdb_idl_txn_*() functions. These are
189 * likely to be more convenient.)
191 * Reading and writing columns and inserting and deleting rows are all
192 * straightforward. The reasons to verify columns are less obvious.
193 * Verification is the key to maintaining transactional integrity. Because
194 * OVSDB handles multiple clients, it can happen that between the time that
195 * OVSDB client A reads a column and writes a new value, OVSDB client B has
196 * written that column. Client A's write should not ordinarily overwrite
197 * client B's, especially if the column in question is a "map" column that
198 * contains several more or less independent data items. If client A adds a
199 * "verify" operation before it writes the column, then the transaction fails
200 * in case client B modifies it first. Client A will then see the new value of
201 * the column and compose a new transaction based on the new contents written
204 * When a transaction is complete, which must be before the next call to
205 * ovsdb_idl_run() on 'idl', call ovsdb_idl_txn_commit() or
206 * ovsdb_idl_txn_abort().
208 * The life-cycle of a transaction looks like this:
210 * 1. Create the transaction and record the initial sequence number:
212 * seqno = ovsdb_idl_get_seqno(idl);
213 * txn = ovsdb_idl_txn_create(idl);
215 * 2. Modify the database with ovsdb_idl_txn_*() functions directly or
218 * 3. Commit the transaction by calling ovsdb_idl_txn_commit(). The first call
219 * to this function probably returns TXN_INCOMPLETE. The client must keep
220 * calling again along as this remains true, calling ovsdb_idl_run() in
221 * between to let the IDL do protocol processing. (If the client doesn't
222 * have anything else to do in the meantime, it can use
223 * ovsdb_idl_txn_commit_block() to avoid having to loop itself.)
225 * 4. If the final status is TXN_TRY_AGAIN, wait for ovsdb_idl_get_seqno() to
226 * change from the saved 'seqno' (it's possible that it's already changed,
227 * in which case the client should not wait at all), then start over from
228 * step 1. Only a call to ovsdb_idl_run() will change the return value of
229 * ovsdb_idl_get_seqno(). (ovsdb_idl_txn_commit_block() calls
233 enum ovsdb_idl_txn_status
{
234 TXN_UNCOMMITTED
, /* Not yet committed or aborted. */
235 TXN_UNCHANGED
, /* Transaction didn't include any changes. */
236 TXN_INCOMPLETE
, /* Commit in progress, please wait. */
237 TXN_ABORTED
, /* ovsdb_idl_txn_abort() called. */
238 TXN_SUCCESS
, /* Commit successful. */
239 TXN_TRY_AGAIN
, /* Commit failed because a "verify" operation
240 * reported an inconsistency, due to a network
241 * problem, or other transient failure. Wait
242 * for a change, then try again. */
243 TXN_NOT_LOCKED
, /* Server hasn't given us the lock yet. */
244 TXN_ERROR
/* Commit failed due to a hard error. */
247 const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status
);
249 struct ovsdb_idl_txn
*ovsdb_idl_txn_create(struct ovsdb_idl
*);
250 void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn
*, const char *, ...)
251 OVS_PRINTF_FORMAT (2, 3);
252 void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn
*);
253 void ovsdb_idl_txn_increment(struct ovsdb_idl_txn
*,
254 const struct ovsdb_idl_row
*,
255 const struct ovsdb_idl_column
*,
257 void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn
*);
258 void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn
*);
259 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit(struct ovsdb_idl_txn
*);
260 enum ovsdb_idl_txn_status
ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn
*);
261 void ovsdb_idl_txn_abort(struct ovsdb_idl_txn
*);
263 const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn
*);
265 int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn
*);
266 const struct uuid
*ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn
*,
267 const struct uuid
*);
269 void ovsdb_idl_txn_write(const struct ovsdb_idl_row
*,
270 const struct ovsdb_idl_column
*,
271 struct ovsdb_datum
*);
272 void ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row
*,
273 const struct ovsdb_idl_column
*,
274 const struct ovsdb_datum
*);
275 void ovsdb_idl_txn_write_partial_map(const struct ovsdb_idl_row
*,
276 const struct ovsdb_idl_column
*,
277 struct ovsdb_datum
*);
278 void ovsdb_idl_txn_delete_partial_map(const struct ovsdb_idl_row
*,
279 const struct ovsdb_idl_column
*,
280 struct ovsdb_datum
*);
281 void ovsdb_idl_txn_write_partial_set(const struct ovsdb_idl_row
*,
282 const struct ovsdb_idl_column
*,
283 struct ovsdb_datum
*);
284 void ovsdb_idl_txn_delete_partial_set(const struct ovsdb_idl_row
*,
285 const struct ovsdb_idl_column
*,
286 struct ovsdb_datum
*);
287 void ovsdb_idl_txn_delete(const struct ovsdb_idl_row
*);
288 const struct ovsdb_idl_row
*ovsdb_idl_txn_insert(
289 struct ovsdb_idl_txn
*, const struct ovsdb_idl_table_class
*,
290 const struct uuid
*);
292 struct ovsdb_idl
*ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn
*);
293 void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl
*);
296 /* ovsdb_idl_loop provides an easy way to manage the transactions related
297 * to 'idl' and to cope with different status during transaction. */
298 struct ovsdb_idl_loop
{
299 struct ovsdb_idl
*idl
;
300 unsigned int skip_seqno
;
302 struct ovsdb_idl_txn
*committing_txn
;
303 unsigned int precommit_seqno
;
305 struct ovsdb_idl_txn
*open_txn
;
307 /* These members allow a client a simple, stateless way to keep track of
308 * transactions that commit: when a transaction commits successfully,
309 * ovsdb_idl_loop_commit_and_wait() copies 'next_cfg' to 'cur_cfg'. Thus,
310 * the client can set 'next_cfg' to a value that indicates a successful
311 * commit and check 'cur_cfg' on each iteration. */
316 #define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) }
318 void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop
*);
319 struct ovsdb_idl_txn
*ovsdb_idl_loop_run(struct ovsdb_idl_loop
*);
320 int ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop
*);
322 /* Conditional Replication
323 * =======================
325 * By default, when the IDL replicates a particular table in the database, it
326 * replicates every row in the table. These functions allow the client to
327 * specify that only selected rows should be replicated, by constructing a
328 * per-table condition that specifies the rows to replicate.
330 * A condition is a disjunction of clauses. The condition is true, and thus a
331 * row is replicated, if any of the clauses evaluates to true for a given row.
332 * (Thus, a condition with no clauses is always false.)
335 struct ovsdb_idl_condition
{
336 struct hmap clauses
; /* Contains "struct ovsdb_idl_clause"s. */
337 bool is_true
; /* Is the condition unconditionally true? */
339 #define OVSDB_IDL_CONDITION_INIT(CONDITION) \
340 { HMAP_INITIALIZER(&(CONDITION)->clauses), false }
342 void ovsdb_idl_condition_init(struct ovsdb_idl_condition
*);
343 void ovsdb_idl_condition_clear(struct ovsdb_idl_condition
*);
344 void ovsdb_idl_condition_destroy(struct ovsdb_idl_condition
*);
345 void ovsdb_idl_condition_add_clause(struct ovsdb_idl_condition
*,
346 enum ovsdb_function function
,
347 const struct ovsdb_idl_column
*column
,
348 const struct ovsdb_datum
*arg
);
349 void ovsdb_idl_condition_add_clause_true(struct ovsdb_idl_condition
*);
350 bool ovsdb_idl_condition_is_true(const struct ovsdb_idl_condition
*);
352 void ovsdb_idl_set_condition(struct ovsdb_idl
*,
353 const struct ovsdb_idl_table_class
*,
354 const struct ovsdb_idl_condition
*);
356 #endif /* ovsdb-idl.h */