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1 | /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Nicira, Inc. | |
2 | * | |
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: | |
6 | * | |
7 | * http://www.apache.org/licenses/LICENSE-2.0 | |
8 | * | |
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. | |
14 | */ | |
15 | ||
16 | #ifndef OVSDB_IDL_H | |
17 | #define OVSDB_IDL_H 1 | |
18 | ||
19 | /* Open vSwitch Database Interface Definition Language (OVSDB IDL). | |
20 | * | |
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. | |
25 | * | |
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. | |
29 | * | |
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 | |
34 | * successfully. | |
35 | */ | |
36 | ||
37 | #include <stdbool.h> | |
38 | #include <stdint.h> | |
39 | #include "compiler.h" | |
40 | #include "ovsdb-types.h" | |
41 | #include "ovsdb-data.h" | |
42 | #include "openvswitch/list.h" | |
43 | #include "ovsdb-condition.h" | |
44 | ||
45 | struct json; | |
46 | struct ovsdb_datum; | |
47 | struct ovsdb_idl_class; | |
48 | struct ovsdb_idl_row; | |
49 | struct ovsdb_idl_column; | |
50 | struct ovsdb_idl_table_class; | |
51 | struct uuid; | |
52 | ||
53 | struct ovsdb_idl *ovsdb_idl_create(const char *remote, | |
54 | const struct ovsdb_idl_class *, | |
55 | bool monitor_everything_by_default, | |
56 | bool retry); | |
57 | void ovsdb_idl_set_remote(struct ovsdb_idl *, const char *, bool); | |
58 | void ovsdb_idl_destroy(struct ovsdb_idl *); | |
59 | ||
60 | void ovsdb_idl_run(struct ovsdb_idl *); | |
61 | void ovsdb_idl_wait(struct ovsdb_idl *); | |
62 | ||
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 *); | |
66 | ||
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 *); | |
73 | ||
74 | bool ovsdb_idl_is_alive(const struct ovsdb_idl *); | |
75 | int ovsdb_idl_get_last_error(const struct ovsdb_idl *); | |
76 | ||
77 | void ovsdb_idl_set_probe_interval(const struct ovsdb_idl *, int probe_interval); | |
78 | ||
79 | void ovsdb_idl_check_consistency(const struct ovsdb_idl *); | |
80 | \f | |
81 | /* Choosing columns and tables to replicate. */ | |
82 | ||
83 | /* Modes with which the IDL can monitor a column. | |
84 | * | |
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. | |
87 | * | |
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 | |
91 | * changes. | |
92 | * | |
93 | * The possible mode combinations are: | |
94 | * | |
95 | * - 0, for a column that a client doesn't care about. | |
96 | * | |
97 | * - (OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT), for a column that a client wants | |
98 | * to track and possibly update. | |
99 | * | |
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. | |
104 | * | |
105 | * - OVDSB_IDL_ALERT without OVSDB_IDL_MONITOR is not valid. | |
106 | * | |
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. | |
110 | */ | |
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) | |
114 | ||
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 *); | |
118 | ||
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 *); | |
121 | ||
122 | /* Change tracking. | |
123 | * | |
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 | |
129 | * available. | |
130 | * | |
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, | |
140 | OVSDB_IDL_CHANGE_MAX | |
141 | }; | |
142 | ||
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); | |
150 | ||
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 *); | |
160 | ||
161 | \f | |
162 | /* Reading the database replica. */ | |
163 | ||
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 *); | |
170 | ||
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 *); | |
179 | ||
180 | bool ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row *); | |
181 | \f | |
182 | /* Transactions. | |
183 | * | |
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.) | |
190 | * | |
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 | |
202 | * by client B. | |
203 | * | |
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(). | |
207 | * | |
208 | * The life-cycle of a transaction looks like this: | |
209 | * | |
210 | * 1. Create the transaction and record the initial sequence number: | |
211 | * | |
212 | * seqno = ovsdb_idl_get_seqno(idl); | |
213 | * txn = ovsdb_idl_txn_create(idl); | |
214 | * | |
215 | * 2. Modify the database with ovsdb_idl_txn_*() functions directly or | |
216 | * indirectly. | |
217 | * | |
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.) | |
224 | * | |
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 | |
230 | * ovsdb_idl_run().) | |
231 | */ | |
232 | ||
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. */ | |
245 | }; | |
246 | ||
247 | const char *ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status); | |
248 | ||
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 *, | |
256 | bool force); | |
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 *); | |
262 | ||
263 | const char *ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn *); | |
264 | ||
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 *); | |
268 | ||
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 *); | |
291 | ||
292 | struct ovsdb_idl *ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn *); | |
293 | void ovsdb_idl_get_initial_snapshot(struct ovsdb_idl *); | |
294 | \f | |
295 | ||
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; | |
301 | ||
302 | struct ovsdb_idl_txn *committing_txn; | |
303 | unsigned int precommit_seqno; | |
304 | ||
305 | struct ovsdb_idl_txn *open_txn; | |
306 | ||
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. */ | |
312 | int64_t cur_cfg; | |
313 | int64_t next_cfg; | |
314 | }; | |
315 | ||
316 | #define OVSDB_IDL_LOOP_INITIALIZER(IDL) { .idl = (IDL) } | |
317 | ||
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 *); | |
321 | \f | |
322 | /* Conditional Replication | |
323 | * ======================= | |
324 | * | |
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. | |
329 | * | |
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.) | |
333 | */ | |
334 | ||
335 | struct ovsdb_idl_condition { | |
336 | struct hmap clauses; /* Contains "struct ovsdb_idl_clause"s. */ | |
337 | bool is_true; /* Is the condition unconditionally true? */ | |
338 | }; | |
339 | #define OVSDB_IDL_CONDITION_INIT(CONDITION) \ | |
340 | { HMAP_INITIALIZER(&(CONDITION)->clauses), false } | |
341 | ||
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 *); | |
351 | ||
352 | void ovsdb_idl_set_condition(struct ovsdb_idl *, | |
353 | const struct ovsdb_idl_table_class *, | |
354 | const struct ovsdb_idl_condition *); | |
355 | ||
356 | #endif /* ovsdb-idl.h */ |