1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 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"
44 struct ovsdb_idl_class;
46 struct ovsdb_idl_column;
47 struct ovsdb_idl_table_class;
50 struct ovsdb_idl *ovsdb_idl_create(const char *remote,
51 const struct ovsdb_idl_class *,
52 bool monitor_everything_by_default,
54 void ovsdb_idl_set_remote(struct ovsdb_idl *, const char *, bool);
55 void ovsdb_idl_destroy(struct ovsdb_idl *);
57 void ovsdb_idl_run(struct ovsdb_idl *);
58 void ovsdb_idl_wait(struct ovsdb_idl *);
60 void ovsdb_idl_set_lock(struct ovsdb_idl *, const char *lock_name);
61 bool ovsdb_idl_has_lock(const struct ovsdb_idl *);
62 bool ovsdb_idl_is_lock_contended(const struct ovsdb_idl *);
64 const struct uuid * ovsdb_idl_get_monitor_id(const struct ovsdb_idl *);
65 unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl *);
66 bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl *);
67 void ovsdb_idl_enable_reconnect(struct ovsdb_idl *);
68 void ovsdb_idl_force_reconnect(struct ovsdb_idl *);
69 void ovsdb_idl_verify_write_only(struct ovsdb_idl *);
71 bool ovsdb_idl_is_alive(const struct ovsdb_idl *);
72 int ovsdb_idl_get_last_error(const struct ovsdb_idl *);
74 void ovsdb_idl_set_probe_interval(const struct ovsdb_idl *, int probe_interval);
76 /* Choosing columns and tables to replicate. */
78 /* Modes with which the IDL can monitor a column.
80 * If no bits are set, the column is not monitored at all. Its value will
81 * always appear to the client to be the default value for its type.
83 * If OVSDB_IDL_MONITOR is set, then the column is replicated. Its value will
84 * reflect the value in the database. If OVSDB_IDL_ALERT is also set, then the
85 * value returned by ovsdb_idl_get_seqno() will change when the column's value
88 * The possible mode combinations are:
90 * - 0, for a column that a client doesn't care about.
92 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants
93 * to track and possibly update.
95 * - OVSDB_IDL_MONITOR, for columns that a client treats as "write-only",
96 * that is, it updates them but doesn't want to get alerted about its own
97 * updates. It also won't be alerted about other clients' updates, so this
98 * is suitable only for use by a client that "owns" a particular column.
100 * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid.
102 * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT | OVSDB_IDL_TRACK), for a column
103 * that a client wants to track using the change tracking
104 * ovsdb_idl_track_get_*() functions.
106 #define OVSDB_IDL_MONITOR (1 << 0) /* Monitor this column? */
107 #define OVSDB_IDL_ALERT (1 << 1) /* Alert client when column updated? */
108 #define OVSDB_IDL_TRACK (1 << 2)
110 void ovsdb_idl_add_column(struct ovsdb_idl *, const struct ovsdb_idl_column *);
111 void ovsdb_idl_add_table(struct ovsdb_idl *,
112 const struct ovsdb_idl_table_class *);
114 void ovsdb_idl_omit(struct ovsdb_idl *, const struct ovsdb_idl_column *);
115 void ovsdb_idl_omit_alert(struct ovsdb_idl *, const struct ovsdb_idl_column *);
119 * In OVSDB, change tracking is applied at each client in the IDL layer. This
120 * means that when a client makes a request to track changes on a particular
121 * table, they are essentially requesting information about the incremental
122 * changes to that table from the point in time that the request is made. Once
123 * the client clears tracked changes, that information will no longer be
126 * The implication of the above is that if a client requires replaying
127 * untracked history, it faces the choice of either trying to remember changes
128 * itself (which translates into a memory leak) or of being structured with a
129 * path for processing the full untracked table as well as a path that
130 * processes incremental changes. */
131 enum ovsdb_idl_change {
132 OVSDB_IDL_CHANGE_INSERT,
133 OVSDB_IDL_CHANGE_MODIFY,
134 OVSDB_IDL_CHANGE_DELETE,
138 /* Row, table sequence numbers */
139 unsigned int ovsdb_idl_table_get_seqno(
140 const struct ovsdb_idl *idl,
141 const struct ovsdb_idl_table_class *table_class);
142 unsigned int ovsdb_idl_row_get_seqno(
143 const struct ovsdb_idl_row *row,
144 enum ovsdb_idl_change change);
146 void ovsdb_idl_track_add_column(struct ovsdb_idl *idl,
147 const struct ovsdb_idl_column *column);
148 void ovsdb_idl_track_add_all(struct ovsdb_idl *idl);
149 const struct ovsdb_idl_row *ovsdb_idl_track_get_first(
150 const struct ovsdb_idl *, const struct ovsdb_idl_table_class *);
151 const struct ovsdb_idl_row *ovsdb_idl_track_get_next(const struct ovsdb_idl_row *);
152 bool ovsdb_idl_track_is_updated(const struct ovsdb_idl_row *row,
153 const struct ovsdb_idl_column *column);
154 void ovsdb_idl_track_clear(const struct ovsdb_idl *);
157 /* Reading the database replica. */
159 const struct ovsdb_idl_row *ovsdb_idl_get_row_for_uuid(
160 const struct ovsdb_idl *, const struct ovsdb_idl_table_class *,
161 const struct uuid *);
162 const struct ovsdb_idl_row *ovsdb_idl_first_row(
163 const struct ovsdb_idl *, const struct ovsdb_idl_table_class *);
164 const struct ovsdb_idl_row *ovsdb_idl_next_row(const struct ovsdb_idl_row *);
166 const struct ovsdb_datum *ovsdb_idl_read(const struct ovsdb_idl_row *,
167 const struct ovsdb_idl_column *);
168 const struct ovsdb_datum *ovsdb_idl_get(const struct ovsdb_idl_row *,
169 const struct ovsdb_idl_column *,
170 enum ovsdb_atomic_type key_type,
171 enum ovsdb_atomic_type value_type);
172 bool ovsdb_idl_is_mutable(const struct ovsdb_idl_row *,
173 const struct ovsdb_idl_column *);
175 bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row *);
179 * A transaction may modify the contents of a database by modifying the values
180 * of columns, deleting rows, inserting rows, or adding checks that columns in
181 * the database have not changed ("verify" operations), through
182 * ovsdb_idl_txn_*() functions. (The OVSDB IDL code generator produces helper
183 * functions that internally call the ovsdb_idl_txn_*() functions. These are
184 * likely to be more convenient.)
186 * Reading and writing columns and inserting and deleting rows are all
187 * straightforward. The reasons to verify columns are less obvious.
188 * Verification is the key to maintaining transactional integrity. Because
189 * OVSDB handles multiple clients, it can happen that between the time that
190 * OVSDB client A reads a column and writes a new value, OVSDB client B has
191 * written that column. Client A's write should not ordinarily overwrite
192 * client B's, especially if the column in question is a "map" column that
193 * contains several more or less independent data items. If client A adds a
194 * "verify" operation before it writes the column, then the transaction fails
195 * in case client B modifies it first. Client A will then see the new value of
196 * the column and compose a new transaction based on the new contents written
199 * When a transaction is complete, which must be before the next call to
200 * ovsdb_idl_run() on 'idl', call ovsdb_idl_txn_commit() or
201 * ovsdb_idl_txn_abort().
203 * The life-cycle of a transaction looks like this:
205 * 1. Create the transaction and record the initial sequence number:
207 * seqno = ovsdb_idl_get_seqno(idl);
208 * txn = ovsdb_idl_txn_create(idl);
210 * 2. Modify the database with ovsdb_idl_txn_*() functions directly or
213 * 3. Commit the transaction by calling ovsdb_idl_txn_commit(). The first call
214 * to this function probably returns TXN_INCOMPLETE. The client must keep
215 * calling again along as this remains true, calling ovsdb_idl_run() in
216 * between to let the IDL do protocol processing. (If the client doesn't
217 * have anything else to do in the meantime, it can use
218 * ovsdb_idl_txn_commit_block() to avoid having to loop itself.)
220 * 4. If the final status is TXN_TRY_AGAIN, wait for ovsdb_idl_get_seqno() to
221 * change from the saved 'seqno' (it's possible that it's already changed,
222 * in which case the client should not wait at all), then start over from
223 * step 1. Only a call to ovsdb_idl_run() will change the return value of
224 * ovsdb_idl_get_seqno(). (ovsdb_idl_txn_commit_block() calls
228 enum ovsdb_idl_txn_status {
229 TXN_UNCOMMITTED, /* Not yet committed or aborted. */
230 TXN_UNCHANGED, /* Transaction didn't include any changes. */
231 TXN_INCOMPLETE, /* Commit in progress, please wait. */
232 TXN_ABORTED, /* ovsdb_idl_txn_abort() called. */
233 TXN_SUCCESS, /* Commit successful. */
234 TXN_TRY_AGAIN, /* Commit failed because a "verify" operation
235 * reported an inconsistency, due to a network
236 * problem, or other transient failure. Wait
237 * for a change, then try again. */
238 TXN_NOT_LOCKED, /* Server hasn't given us the lock yet. */
239 TXN_ERROR /* Commit failed due to a hard error. */
242 const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status);
244 struct ovsdb_idl_txn *ovsdb_idl_txn_create(struct ovsdb_idl *);
245 void ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn *, const char *, ...)
246 OVS_PRINTF_FORMAT (2, 3);
247 void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn *);
248 void ovsdb_idl_txn_increment(struct ovsdb_idl_txn *,
249 const struct ovsdb_idl_row *,
250 const struct ovsdb_idl_column *);
251 void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *);
252 void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn *);
253 enum ovsdb_idl_txn_status ovsdb_idl_txn_commit(struct ovsdb_idl_txn *);
254 enum ovsdb_idl_txn_status ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn *);
255 void ovsdb_idl_txn_abort(struct ovsdb_idl_txn *);
257 const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn *);
259 int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn *);
260 const struct uuid *ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn *,
261 const struct uuid *);
263 void ovsdb_idl_txn_write(const struct ovsdb_idl_row *,
264 const struct ovsdb_idl_column *,
265 struct ovsdb_datum *);
266 void ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row *,
267 const struct ovsdb_idl_column *,
268 const struct ovsdb_datum *);
269 void ovsdb_idl_txn_write_partial_map(const struct ovsdb_idl_row *,
270 const struct ovsdb_idl_column *,
271 struct ovsdb_datum *);
272 void ovsdb_idl_txn_delete_partial_map(const struct ovsdb_idl_row *,
273 const struct ovsdb_idl_column *,
274 struct ovsdb_datum *);
275 void ovsdb_idl_txn_delete(const struct ovsdb_idl_row *);
276 const struct ovsdb_idl_row *ovsdb_idl_txn_insert(
277 struct ovsdb_idl_txn *, const struct ovsdb_idl_table_class *,
278 const struct uuid *);
280 struct ovsdb_idl *ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn *);
281 void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl *);
284 /* ovsdb_idl_loop provides an easy way to manage the transactions related
285 * to 'idl' and to cope with different status during transaction. */
286 struct ovsdb_idl_loop {
287 struct ovsdb_idl *idl;
288 unsigned int skip_seqno;
290 struct ovsdb_idl_txn *committing_txn;
291 unsigned int precommit_seqno;
293 struct ovsdb_idl_txn *open_txn;
296 #define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) }
298 void ovsdb_idl_loop_destroy(struct ovsdb_idl_loop *);
299 struct ovsdb_idl_txn *ovsdb_idl_loop_run(struct ovsdb_idl_loop *);
300 void ovsdb_idl_loop_commit_and_wait(struct ovsdb_idl_loop *);
302 #endif /* ovsdb-idl.h */