ovsdb/monitor.c

   1 /*
   2  * Copyright (c) 2015 Nicira, Inc.
   3  *
   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:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  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.
  15  */
  16
  17 #include <config.h>
  18
  19 #include <errno.h>
  20
  21 #include "bitmap.h"
  22 #include "column.h"
  23 #include "dynamic-string.h"
  24 #include "json.h"
  25 #include "jsonrpc.h"
  26 #include "ovsdb-error.h"
  27 #include "ovsdb-parser.h"
  28 #include "ovsdb.h"
  29 #include "row.h"
  30 #include "simap.h"
  31 #include "hash.h"
  32 #include "table.h"
  33 #include "hash.h"
  34 #include "timeval.h"
  35 #include "transaction.h"
  36 #include "jsonrpc-server.h"
  37 #include "monitor.h"
  38 #include "openvswitch/vlog.h"
  39
  40
  41 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
  42 static struct hmap ovsdb_monitors = HMAP_INITIALIZER(&ovsdb_monitors);
  43
  44 /*  Backend monitor.
  45  *
  46  *  ovsdb_monitor keep track of the ovsdb changes.
  47  */
  48
  49 /* A collection of tables being monitored. */
  50 struct ovsdb_monitor {
  51     struct ovsdb_replica replica;
  52     struct shash tables;     /* Holds "struct ovsdb_monitor_table"s. */
  53     struct ovs_list jsonrpc_monitors;  /* Contains "jsonrpc_monitor_node"s. */
  54     struct ovsdb *db;
  55     uint64_t n_transactions;      /* Count number of committed transactions. */
  56     struct hmap_node hmap_node;   /* Elements within ovsdb_monitors.  */
  57     struct hmap json_cache;       /* Contains "ovsdb_monitor_json_cache_node"s.*/
  58 };
  59
  60 /* A json object of updates between 'from_txn' and 'dbmon->n_transactions'
  61  * inclusive.  */
  62 struct ovsdb_monitor_json_cache_node {
  63     struct hmap_node hmap_node;   /* Elements in json cache. */
  64     uint64_t from_txn;
  65     struct json *json;            /* Null, or a cloned of json */
  66 };
  67
  68 struct jsonrpc_monitor_node {
  69     struct ovsdb_jsonrpc_monitor *jsonrpc_monitor;
  70     struct ovs_list node;
  71 };
  72
  73 /* A particular column being monitored. */
  74 struct ovsdb_monitor_column {
  75     const struct ovsdb_column *column;
  76     enum ovsdb_monitor_selection select;
  77 };
  78
  79 /* A row that has changed in a monitored table. */
  80 struct ovsdb_monitor_row {
  81     struct hmap_node hmap_node; /* In ovsdb_jsonrpc_monitor_table.changes. */
  82     struct uuid uuid;           /* UUID of row that changed. */
  83     struct ovsdb_datum *old;    /* Old data, NULL for an inserted row. */
  84     struct ovsdb_datum *new;    /* New data, NULL for a deleted row. */
  85 };
  86
  87 /* Contains 'struct ovsdb_monitor_row's for rows that have been
  88  * updated but not yet flushed to all the jsonrpc connection.
  89  *
  90  * 'n_refs' represent the number of jsonrpc connections that have
  91  * not received updates. Generate the update for the last jsonprc
  92  * connection will also destroy the whole "struct ovsdb_monitor_changes"
  93  * object.
  94  *
  95  * 'transaction' stores the first update's transaction id.
  96  * */
  97 struct ovsdb_monitor_changes {
  98     struct ovsdb_monitor_table *mt;
  99     struct hmap rows;
 100     int n_refs;
 101     uint64_t transaction;
 102     struct hmap_node hmap_node;  /* Element in ovsdb_monitor_tables' changes
 103                                     hmap.  */
 104 };
 105
 106 /* A particular table being monitored. */
 107 struct ovsdb_monitor_table {
 108     const struct ovsdb_table *table;
 109
 110     /* This is the union (bitwise-OR) of the 'select' values in all of the
 111      * members of 'columns' below. */
 112     enum ovsdb_monitor_selection select;
 113
 114     /* Columns being monitored. */
 115     struct ovsdb_monitor_column *columns;
 116     size_t n_columns;
 117
 118     /* Contains 'ovsdb_monitor_changes' indexed by 'transaction'. */
 119     struct hmap changes;
 120 };
 121
 122 static void ovsdb_monitor_destroy(struct ovsdb_monitor *dbmon);
 123 static struct ovsdb_monitor_changes * ovsdb_monitor_table_add_changes(
 124     struct ovsdb_monitor_table *mt, uint64_t next_txn);
 125 static struct ovsdb_monitor_changes *ovsdb_monitor_table_find_changes(
 126     struct ovsdb_monitor_table *mt, uint64_t unflushed);
 127 static void ovsdb_monitor_changes_destroy(
 128                                   struct ovsdb_monitor_changes *changes);
 129 static void ovsdb_monitor_table_track_changes(struct ovsdb_monitor_table *mt,
 130                                   uint64_t unflushed);
 131
 132 static struct ovsdb_monitor_json_cache_node *
 133 ovsdb_monitor_json_cache_search(const struct ovsdb_monitor *dbmon,
 134                                 uint64_t from_txn)
 135 {
 136     struct ovsdb_monitor_json_cache_node *node;
 137     uint32_t hash = hash_uint64(from_txn);
 138
 139     HMAP_FOR_EACH_WITH_HASH(node, hmap_node, hash, &dbmon->json_cache) {
 140         if (node->from_txn == from_txn) {
 141             return node;
 142         }
 143     }
 144
 145     return NULL;
 146 }
 147
 148 static void
 149 ovsdb_monitor_json_cache_insert(struct ovsdb_monitor *dbmon,
 150                                 uint64_t from_txn, struct json *json)
 151 {
 152     struct ovsdb_monitor_json_cache_node *node;
 153     uint32_t hash;
 154
 155     node = xmalloc(sizeof *node);
 156
 157     hash = hash_uint64(from_txn);
 158     node->from_txn = from_txn;
 159     node->json = json ? json_clone(json) : NULL;
 160
 161     hmap_insert(&dbmon->json_cache, &node->hmap_node, hash);
 162 }
 163
 164 static void
 165 ovsdb_monitor_json_cache_flush(struct ovsdb_monitor *dbmon)
 166 {
 167     struct ovsdb_monitor_json_cache_node *node, *next;
 168
 169     HMAP_FOR_EACH_SAFE(node, next, hmap_node, &dbmon->json_cache) {
 170         hmap_remove(&dbmon->json_cache, &node->hmap_node);
 171         json_destroy(node->json);
 172         free(node);
 173     }
 174 }
 175
 176 static int
 177 compare_ovsdb_monitor_column(const void *a_, const void *b_)
 178 {
 179     const struct ovsdb_monitor_column *a = a_;
 180     const struct ovsdb_monitor_column *b = b_;
 181
 182     return a->column < b->column ? -1 : a->column > b->column;
 183 }
 184
 185 static struct ovsdb_monitor *
 186 ovsdb_monitor_cast(struct ovsdb_replica *replica)
 187 {
 188     ovs_assert(replica->class == &ovsdb_jsonrpc_replica_class);
 189     return CONTAINER_OF(replica, struct ovsdb_monitor, replica);
 190 }
 191
 192 /* Finds and returns the ovsdb_monitor_row in 'mt->changes->rows' for the
 193  * given 'uuid', or NULL if there is no such row. */
 194 static struct ovsdb_monitor_row *
 195 ovsdb_monitor_changes_row_find(const struct ovsdb_monitor_changes *changes,
 196                                const struct uuid *uuid)
 197 {
 198     struct ovsdb_monitor_row *row;
 199
 200     HMAP_FOR_EACH_WITH_HASH (row, hmap_node, uuid_hash(uuid),
 201                              &changes->rows) {
 202         if (uuid_equals(uuid, &row->uuid)) {
 203             return row;
 204         }
 205     }
 206     return NULL;
 207 }
 208
 209 /* Allocates an array of 'mt->n_columns' ovsdb_datums and initializes them as
 210  * copies of the data in 'row' drawn from the columns represented by
 211  * mt->columns[].  Returns the array.
 212  *
 213  * If 'row' is NULL, returns NULL. */
 214 static struct ovsdb_datum *
 215 clone_monitor_row_data(const struct ovsdb_monitor_table *mt,
 216                        const struct ovsdb_row *row)
 217 {
 218     struct ovsdb_datum *data;
 219     size_t i;
 220
 221     if (!row) {
 222         return NULL;
 223     }
 224
 225     data = xmalloc(mt->n_columns * sizeof *data);
 226     for (i = 0; i < mt->n_columns; i++) {
 227         const struct ovsdb_column *c = mt->columns[i].column;
 228         const struct ovsdb_datum *src = &row->fields[c->index];
 229         struct ovsdb_datum *dst = &data[i];
 230         const struct ovsdb_type *type = &c->type;
 231
 232         ovsdb_datum_clone(dst, src, type);
 233     }
 234     return data;
 235 }
 236
 237 /* Replaces the mt->n_columns ovsdb_datums in row[] by copies of the data from
 238  * in 'row' drawn from the columns represented by mt->columns[]. */
 239 static void
 240 update_monitor_row_data(const struct ovsdb_monitor_table *mt,
 241                         const struct ovsdb_row *row,
 242                         struct ovsdb_datum *data)
 243 {
 244     size_t i;
 245
 246     for (i = 0; i < mt->n_columns; i++) {
 247         const struct ovsdb_column *c = mt->columns[i].column;
 248         const struct ovsdb_datum *src = &row->fields[c->index];
 249         struct ovsdb_datum *dst = &data[i];
 250         const struct ovsdb_type *type = &c->type;
 251
 252         if (!ovsdb_datum_equals(src, dst, type)) {
 253             ovsdb_datum_destroy(dst, type);
 254             ovsdb_datum_clone(dst, src, type);
 255         }
 256     }
 257 }
 258
 259 /* Frees all of the mt->n_columns ovsdb_datums in data[], using the types taken
 260  * from mt->columns[], plus 'data' itself. */
 261 static void
 262 free_monitor_row_data(const struct ovsdb_monitor_table *mt,
 263                       struct ovsdb_datum *data)
 264 {
 265     if (data) {
 266         size_t i;
 267
 268         for (i = 0; i < mt->n_columns; i++) {
 269             const struct ovsdb_column *c = mt->columns[i].column;
 270
 271             ovsdb_datum_destroy(&data[i], &c->type);
 272         }
 273         free(data);
 274     }
 275 }
 276
 277 /* Frees 'row', which must have been created from 'mt'. */
 278 static void
 279 ovsdb_monitor_row_destroy(const struct ovsdb_monitor_table *mt,
 280                           struct ovsdb_monitor_row *row)
 281 {
 282     if (row) {
 283         free_monitor_row_data(mt, row->old);
 284         free_monitor_row_data(mt, row->new);
 285         free(row);
 286     }
 287 }
 288
 289 void
 290 ovsdb_monitor_add_jsonrpc_monitor(struct ovsdb_monitor *dbmon,
 291                                   struct ovsdb_jsonrpc_monitor *jsonrpc_monitor)
 292 {
 293     struct jsonrpc_monitor_node *jm;
 294
 295     jm = xzalloc(sizeof *jm);
 296     jm->jsonrpc_monitor = jsonrpc_monitor;
 297     list_push_back(&dbmon->jsonrpc_monitors, &jm->node);
 298 }
 299
 300 struct ovsdb_monitor *
 301 ovsdb_monitor_create(struct ovsdb *db,
 302                      struct ovsdb_jsonrpc_monitor *jsonrpc_monitor)
 303 {
 304     struct ovsdb_monitor *dbmon;
 305
 306     dbmon = xzalloc(sizeof *dbmon);
 307
 308     ovsdb_replica_init(&dbmon->replica, &ovsdb_jsonrpc_replica_class);
 309     ovsdb_add_replica(db, &dbmon->replica);
 310     list_init(&dbmon->jsonrpc_monitors);
 311     dbmon->db = db;
 312     dbmon->n_transactions = 0;
 313     shash_init(&dbmon->tables);
 314     hmap_node_nullify(&dbmon->hmap_node);
 315     hmap_init(&dbmon->json_cache);
 316
 317     ovsdb_monitor_add_jsonrpc_monitor(dbmon, jsonrpc_monitor);
 318     return dbmon;
 319 }
 320
 321 void
 322 ovsdb_monitor_add_table(struct ovsdb_monitor *m,
 323                         const struct ovsdb_table *table)
 324 {
 325     struct ovsdb_monitor_table *mt;
 326
 327     mt = xzalloc(sizeof *mt);
 328     mt->table = table;
 329     shash_add(&m->tables, table->schema->name, mt);
 330     hmap_init(&mt->changes);
 331 }
 332
 333 void
 334 ovsdb_monitor_add_column(struct ovsdb_monitor *dbmon,
 335                          const struct ovsdb_table *table,
 336                          const struct ovsdb_column *column,
 337                          enum ovsdb_monitor_selection select,
 338                          size_t *allocated_columns)
 339 {
 340     struct ovsdb_monitor_table *mt;
 341     struct ovsdb_monitor_column *c;
 342
 343     mt = shash_find_data(&dbmon->tables, table->schema->name);
 344
 345     if (mt->n_columns >= *allocated_columns) {
 346         mt->columns = x2nrealloc(mt->columns, allocated_columns,
 347                                  sizeof *mt->columns);
 348     }
 349
 350     mt->select |= select;
 351     c = &mt->columns[mt->n_columns++];
 352     c->column = column;
 353     c->select = select;
 354 }
 355
 356 /* Check for duplicated column names. Return the first
 357  * duplicated column's name if found. Otherwise return
 358  * NULL.  */
 359 const char * OVS_WARN_UNUSED_RESULT
 360 ovsdb_monitor_table_check_duplicates(struct ovsdb_monitor *m,
 361                                      const struct ovsdb_table *table)
 362 {
 363     struct ovsdb_monitor_table *mt;
 364     int i;
 365
 366     mt = shash_find_data(&m->tables, table->schema->name);
 367
 368     if (mt) {
 369         /* Check for duplicate columns. */
 370         qsort(mt->columns, mt->n_columns, sizeof *mt->columns,
 371               compare_ovsdb_monitor_column);
 372         for (i = 1; i < mt->n_columns; i++) {
 373             if (mt->columns[i].column == mt->columns[i - 1].column) {
 374                 return mt->columns[i].column->name;
 375             }
 376         }
 377     }
 378
 379     return NULL;
 380 }
 381
 382 static struct ovsdb_monitor_changes *
 383 ovsdb_monitor_table_add_changes(struct ovsdb_monitor_table *mt,
 384                                 uint64_t next_txn)
 385 {
 386     struct ovsdb_monitor_changes *changes;
 387
 388     changes = xzalloc(sizeof *changes);
 389
 390     changes->transaction = next_txn;
 391     changes->mt = mt;
 392     changes->n_refs = 1;
 393     hmap_init(&changes->rows);
 394     hmap_insert(&mt->changes, &changes->hmap_node, hash_uint64(next_txn));
 395
 396     return changes;
 397 };
 398
 399 static struct ovsdb_monitor_changes *
 400 ovsdb_monitor_table_find_changes(struct ovsdb_monitor_table *mt,
 401                                  uint64_t transaction)
 402 {
 403     struct ovsdb_monitor_changes *changes;
 404     size_t hash = hash_uint64(transaction);
 405
 406     HMAP_FOR_EACH_WITH_HASH(changes, hmap_node, hash, &mt->changes) {
 407         if (changes->transaction == transaction) {
 408             return changes;
 409         }
 410     }
 411
 412     return NULL;
 413 }
 414
 415 /* Stop currently tracking changes to table 'mt' since 'transaction'.
 416  *
 417  * Return 'true' if the 'transaction' is being tracked. 'false' otherwise. */
 418 static void
 419 ovsdb_monitor_table_untrack_changes(struct ovsdb_monitor_table *mt,
 420                                     uint64_t transaction)
 421 {
 422     struct ovsdb_monitor_changes *changes =
 423                 ovsdb_monitor_table_find_changes(mt, transaction);
 424     if (changes) {
 425         if (--changes->n_refs == 0) {
 426             hmap_remove(&mt->changes, &changes->hmap_node);
 427             ovsdb_monitor_changes_destroy(changes);
 428         }
 429     }
 430 }
 431
 432 /* Start tracking changes to table 'mt' begins from 'transaction' inclusive.
 433  */
 434 static void
 435 ovsdb_monitor_table_track_changes(struct ovsdb_monitor_table *mt,
 436                                   uint64_t transaction)
 437 {
 438     struct ovsdb_monitor_changes *changes;
 439
 440     changes = ovsdb_monitor_table_find_changes(mt, transaction);
 441     if (changes) {
 442         changes->n_refs++;
 443     } else {
 444         ovsdb_monitor_table_add_changes(mt, transaction);
 445     }
 446 }
 447
 448 static void
 449 ovsdb_monitor_changes_destroy(struct ovsdb_monitor_changes *changes)
 450 {
 451     struct ovsdb_monitor_row *row, *next;
 452
 453     HMAP_FOR_EACH_SAFE (row, next, hmap_node, &changes->rows) {
 454         hmap_remove(&changes->rows, &row->hmap_node);
 455         ovsdb_monitor_row_destroy(changes->mt, row);
 456     }
 457     hmap_destroy(&changes->rows);
 458     free(changes);
 459 }
 460
 461 /* Returns JSON for a <row-update> (as described in RFC 7047) for 'row' within
 462  * 'mt', or NULL if no row update should be sent.
 463  *
 464  * The caller should specify 'initial' as true if the returned JSON is going to
 465  * be used as part of the initial reply to a "monitor" request, false if it is
 466  * going to be used as part of an "update" notification.
 467  *
 468  * 'changed' must be a scratch buffer for internal use that is at least
 469  * bitmap_n_bytes(mt->n_columns) bytes long. */
 470 static struct json *
 471 ovsdb_monitor_compose_row_update(
 472     const struct ovsdb_monitor_table *mt,
 473     const struct ovsdb_monitor_row *row,
 474     bool initial, unsigned long int *changed)
 475 {
 476     enum ovsdb_monitor_selection type;
 477     struct json *old_json, *new_json;
 478     struct json *row_json;
 479     size_t i;
 480
 481     type = (initial ? OJMS_INITIAL
 482             : !row->old ? OJMS_INSERT
 483             : !row->new ? OJMS_DELETE
 484             : OJMS_MODIFY);
 485     if (!(mt->select & type)) {
 486         return NULL;
 487     }
 488
 489     if (type == OJMS_MODIFY) {
 490         size_t n_changes;
 491
 492         n_changes = 0;
 493         memset(changed, 0, bitmap_n_bytes(mt->n_columns));
 494         for (i = 0; i < mt->n_columns; i++) {
 495             const struct ovsdb_column *c = mt->columns[i].column;
 496             if (!ovsdb_datum_equals(&row->old[i], &row->new[i], &c->type)) {
 497                 bitmap_set1(changed, i);
 498                 n_changes++;
 499             }
 500         }
 501         if (!n_changes) {
 502             /* No actual changes: presumably a row changed and then
 503              * changed back later. */
 504             return NULL;
 505         }
 506     }
 507
 508     row_json = json_object_create();
 509     old_json = new_json = NULL;
 510     if (type & (OJMS_DELETE | OJMS_MODIFY)) {
 511         old_json = json_object_create();
 512         json_object_put(row_json, "old", old_json);
 513     }
 514     if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
 515         new_json = json_object_create();
 516         json_object_put(row_json, "new", new_json);
 517     }
 518     for (i = 0; i < mt->n_columns; i++) {
 519         const struct ovsdb_monitor_column *c = &mt->columns[i];
 520
 521         if (!(type & c->select)) {
 522             /* We don't care about this type of change for this
 523              * particular column (but we will care about it for some
 524              * other column). */
 525             continue;
 526         }
 527
 528         if ((type == OJMS_MODIFY && bitmap_is_set(changed, i))
 529             || type == OJMS_DELETE) {
 530             json_object_put(old_json, c->column->name,
 531                             ovsdb_datum_to_json(&row->old[i],
 532                                                 &c->column->type));
 533         }
 534         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
 535             json_object_put(new_json, c->column->name,
 536                             ovsdb_datum_to_json(&row->new[i],
 537                                                 &c->column->type));
 538         }
 539     }
 540
 541     return row_json;
 542 }
 543
 544 /* Constructs and returns JSON for a <table-updates> object (as described in
 545  * RFC 7047) for all the outstanding changes within 'monitor', starting from
 546  * 'transaction'.  */
 547 static struct json*
 548 ovsdb_monitor_compose_update(struct ovsdb_monitor *dbmon,
 549                              bool initial, uint64_t transaction)
 550 {
 551     struct shash_node *node;
 552     unsigned long int *changed;
 553     struct json *json;
 554     size_t max_columns;
 555
 556     max_columns = 0;
 557     SHASH_FOR_EACH (node, &dbmon->tables) {
 558         struct ovsdb_monitor_table *mt = node->data;
 559
 560         max_columns = MAX(max_columns, mt->n_columns);
 561     }
 562     changed = xmalloc(bitmap_n_bytes(max_columns));
 563
 564     json = NULL;
 565     SHASH_FOR_EACH (node, &dbmon->tables) {
 566         struct ovsdb_monitor_table *mt = node->data;
 567         struct ovsdb_monitor_row *row, *next;
 568         struct ovsdb_monitor_changes *changes;
 569         struct json *table_json = NULL;
 570
 571         changes = ovsdb_monitor_table_find_changes(mt, transaction);
 572         if (!changes) {
 573             continue;
 574         }
 575
 576         HMAP_FOR_EACH_SAFE (row, next, hmap_node, &changes->rows) {
 577             struct json *row_json;
 578
 579             row_json = ovsdb_monitor_compose_row_update(
 580                 mt, row, initial, changed);
 581             if (row_json) {
 582                 char uuid[UUID_LEN + 1];
 583
 584                 /* Create JSON object for transaction overall. */
 585                 if (!json) {
 586                     json = json_object_create();
 587                 }
 588
 589                 /* Create JSON object for transaction on this table. */
 590                 if (!table_json) {
 591                     table_json = json_object_create();
 592                     json_object_put(json, mt->table->schema->name, table_json);
 593                 }
 594
 595                 /* Add JSON row to JSON table. */
 596                 snprintf(uuid, sizeof uuid, UUID_FMT, UUID_ARGS(&row->uuid));
 597                 json_object_put(table_json, uuid, row_json);
 598             }
 599         }
 600     }
 601     free(changed);
 602
 603     return json;
 604 }
 605
 606 /* Returns JSON for a <table-updates> object (as described in RFC 7047)
 607  * for all the outstanding changes within 'monitor' that starts from
 608  * '*unflushed' transaction id.
 609  *
 610  * The caller should specify 'initial' as true if the returned JSON is going to
 611  * be used as part of the initial reply to a "monitor" request, false if it is
 612  * going to be used as part of an "update" notification. */
 613 struct json *
 614 ovsdb_monitor_get_update(struct ovsdb_monitor *dbmon,
 615                          bool initial, uint64_t *unflushed)
 616 {
 617     struct ovsdb_monitor_json_cache_node *cache_node;
 618     struct shash_node *node;
 619     struct json *json;
 620     uint64_t prev_txn = *unflushed;
 621     uint64_t next_txn = dbmon->n_transactions + 1;
 622
 623     /* Return a clone of cached json if one exists. Otherwise,
 624      * generate a new one and add it to the cache.  */
 625     cache_node = ovsdb_monitor_json_cache_search(dbmon, prev_txn);
 626     if (cache_node) {
 627         json = cache_node->json ? json_clone(cache_node->json) : NULL;
 628     } else {
 629         json = ovsdb_monitor_compose_update(dbmon, initial, prev_txn);
 630         ovsdb_monitor_json_cache_insert(dbmon, prev_txn, json);
 631     }
 632
 633     /* Maintain transaction id of 'changes'. */
 634     SHASH_FOR_EACH (node, &dbmon->tables) {
 635         struct ovsdb_monitor_table *mt = node->data;
 636
 637         ovsdb_monitor_table_untrack_changes(mt, prev_txn);
 638         ovsdb_monitor_table_track_changes(mt, next_txn);
 639     }
 640     *unflushed = next_txn;
 641
 642     return json;
 643 }
 644
 645 bool
 646 ovsdb_monitor_needs_flush(struct ovsdb_monitor *dbmon,
 647                           uint64_t next_transaction)
 648 {
 649     ovs_assert(next_transaction <= dbmon->n_transactions + 1);
 650     return (next_transaction <= dbmon->n_transactions);
 651 }
 652
 653 void
 654 ovsdb_monitor_table_add_select(struct ovsdb_monitor *dbmon,
 655                                const struct ovsdb_table *table,
 656                                enum ovsdb_monitor_selection select)
 657 {
 658     struct ovsdb_monitor_table * mt;
 659
 660     mt = shash_find_data(&dbmon->tables, table->schema->name);
 661     mt->select |= select;
 662 }
 663
 664 struct ovsdb_monitor_aux {
 665     const struct ovsdb_monitor *monitor;
 666     struct ovsdb_monitor_table *mt;
 667 };
 668
 669 static void
 670 ovsdb_monitor_init_aux(struct ovsdb_monitor_aux *aux,
 671                        const struct ovsdb_monitor *m)
 672 {
 673     aux->monitor = m;
 674     aux->mt = NULL;
 675 }
 676
 677 static void
 678 ovsdb_monitor_changes_update(const struct ovsdb_row *old,
 679                              const struct ovsdb_row *new,
 680                              const struct ovsdb_monitor_table *mt,
 681                              struct ovsdb_monitor_changes *changes)
 682 {
 683     const struct uuid *uuid = ovsdb_row_get_uuid(new ? new : old);
 684     struct ovsdb_monitor_row *change;
 685
 686     change = ovsdb_monitor_changes_row_find(changes, uuid);
 687     if (!change) {
 688         change = xzalloc(sizeof *change);
 689         hmap_insert(&changes->rows, &change->hmap_node, uuid_hash(uuid));
 690         change->uuid = *uuid;
 691         change->old = clone_monitor_row_data(mt, old);
 692         change->new = clone_monitor_row_data(mt, new);
 693     } else {
 694         if (new) {
 695             update_monitor_row_data(mt, new, change->new);
 696         } else {
 697             free_monitor_row_data(mt, change->new);
 698             change->new = NULL;
 699
 700             if (!change->old) {
 701                 /* This row was added then deleted.  Forget about it. */
 702                 hmap_remove(&changes->rows, &change->hmap_node);
 703                 free(change);
 704             }
 705         }
 706     }
 707 }
 708
 709 static bool
 710 ovsdb_monitor_change_cb(const struct ovsdb_row *old,
 711                         const struct ovsdb_row *new,
 712                         const unsigned long int *changed OVS_UNUSED,
 713                         void *aux_)
 714 {
 715     struct ovsdb_monitor_aux *aux = aux_;
 716     const struct ovsdb_monitor *m = aux->monitor;
 717     struct ovsdb_table *table = new ? new->table : old->table;
 718     struct ovsdb_monitor_table *mt;
 719     struct ovsdb_monitor_changes *changes;
 720
 721     if (!aux->mt || table != aux->mt->table) {
 722         aux->mt = shash_find_data(&m->tables, table->schema->name);
 723         if (!aux->mt) {
 724             /* We don't care about rows in this table at all.  Tell the caller
 725              * to skip it.  */
 726             return false;
 727         }
 728     }
 729     mt = aux->mt;
 730
 731     HMAP_FOR_EACH(changes, hmap_node, &mt->changes) {
 732         ovsdb_monitor_changes_update(old, new, mt, changes);
 733     }
 734     return true;
 735 }
 736
 737 void
 738 ovsdb_monitor_get_initial(const struct ovsdb_monitor *dbmon)
 739 {
 740     struct ovsdb_monitor_aux aux;
 741     struct shash_node *node;
 742
 743     ovsdb_monitor_init_aux(&aux, dbmon);
 744     SHASH_FOR_EACH (node, &dbmon->tables) {
 745         struct ovsdb_monitor_table *mt = node->data;
 746
 747         if (mt->select & OJMS_INITIAL) {
 748             struct ovsdb_row *row;
 749             struct ovsdb_monitor_changes *changes;
 750
 751             changes = ovsdb_monitor_table_find_changes(mt, 0);
 752             if (!changes) {
 753                 changes = ovsdb_monitor_table_add_changes(mt, 0);
 754                 HMAP_FOR_EACH (row, hmap_node, &mt->table->rows) {
 755                     ovsdb_monitor_changes_update(NULL, row, mt, changes);
 756                 }
 757             } else {
 758                 changes->n_refs++;
 759             }
 760         }
 761     }
 762 }
 763
 764 void
 765 ovsdb_monitor_remove_jsonrpc_monitor(struct ovsdb_monitor *dbmon,
 766                    struct ovsdb_jsonrpc_monitor *jsonrpc_monitor)
 767 {
 768     struct jsonrpc_monitor_node *jm;
 769
 770     if (list_is_empty(&dbmon->jsonrpc_monitors)) {
 771         ovsdb_monitor_destroy(dbmon);
 772         return;
 773     }
 774
 775     /* Find and remove the jsonrpc monitor from the list.  */
 776     LIST_FOR_EACH(jm, node, &dbmon->jsonrpc_monitors) {
 777         if (jm->jsonrpc_monitor == jsonrpc_monitor) {
 778             list_remove(&jm->node);
 779             free(jm);
 780
 781             /* Destroy ovsdb monitor if this is the last user.  */
 782             if (list_is_empty(&dbmon->jsonrpc_monitors)) {
 783                 ovsdb_monitor_destroy(dbmon);
 784             }
 785
 786             return;
 787         };
 788     }
 789
 790     /* Should never reach here. jsonrpc_monitor should be on the list.  */
 791     OVS_NOT_REACHED();
 792 }
 793
 794 static bool
 795 ovsdb_monitor_table_equal(const struct ovsdb_monitor_table *a,
 796                           const struct ovsdb_monitor_table *b)
 797 {
 798     size_t i;
 799
 800     if ((a->table != b->table) ||
 801         (a->select != b->select) ||
 802         (a->n_columns != b->n_columns)) {
 803         return false;
 804     }
 805
 806     for (i = 0; i < a->n_columns; i++) {
 807         if ((a->columns[i].column != b->columns[i].column) ||
 808             (a->columns[i].select != b->columns[i].select)) {
 809             return false;
 810         }
 811     }
 812
 813     return true;
 814 }
 815
 816 static bool
 817 ovsdb_monitor_equal(const struct ovsdb_monitor *a,
 818                     const struct ovsdb_monitor *b)
 819 {
 820     struct shash_node *node;
 821
 822     if (shash_count(&a->tables) != shash_count(&b->tables)) {
 823         return false;
 824     }
 825
 826     SHASH_FOR_EACH(node, &a->tables) {
 827         const struct ovsdb_monitor_table *mta = node->data;
 828         const struct ovsdb_monitor_table *mtb;
 829
 830         mtb = shash_find_data(&b->tables, node->name);
 831         if (!mtb) {
 832             return false;
 833         }
 834
 835         if (!ovsdb_monitor_table_equal(mta, mtb)) {
 836             return false;
 837         }
 838     }
 839
 840     return true;
 841 }
 842
 843 static size_t
 844 ovsdb_monitor_hash(const struct ovsdb_monitor *dbmon, size_t basis)
 845 {
 846     const struct shash_node **nodes;
 847     size_t i, j, n;
 848
 849     nodes = shash_sort(&dbmon->tables);
 850     n = shash_count(&dbmon->tables);
 851
 852     for (i = 0; i < n; i++) {
 853         struct ovsdb_monitor_table *mt = nodes[i]->data;
 854
 855         basis = hash_pointer(mt->table, basis);
 856         basis = hash_3words(mt->select, mt->n_columns, basis);
 857
 858         for (j = 0; j < mt->n_columns; j++) {
 859             basis = hash_pointer(mt->columns[j].column, basis);
 860             basis = hash_2words(mt->columns[j].select, basis);
 861         }
 862     }
 863     free(nodes);
 864
 865     return basis;
 866 }
 867
 868 struct ovsdb_monitor *
 869 ovsdb_monitor_add(struct ovsdb_monitor *new_dbmon)
 870 {
 871     struct ovsdb_monitor *dbmon;
 872     size_t hash;
 873
 874     /* New_dbmon should be associated with only one jsonrpc
 875      * connections.  */
 876     ovs_assert(list_is_singleton(&new_dbmon->jsonrpc_monitors));
 877
 878     hash = ovsdb_monitor_hash(new_dbmon, 0);
 879     HMAP_FOR_EACH_WITH_HASH(dbmon, hmap_node, hash, &ovsdb_monitors) {
 880         if (ovsdb_monitor_equal(dbmon,  new_dbmon)) {
 881             return dbmon;
 882         }
 883     }
 884
 885     hmap_insert(&ovsdb_monitors, &new_dbmon->hmap_node, hash);
 886     return new_dbmon;
 887 }
 888
 889 static void
 890 ovsdb_monitor_destroy(struct ovsdb_monitor *dbmon)
 891 {
 892     struct shash_node *node;
 893
 894     list_remove(&dbmon->replica.node);
 895
 896     if (!hmap_node_is_null(&dbmon->hmap_node)) {
 897         hmap_remove(&ovsdb_monitors, &dbmon->hmap_node);
 898     }
 899
 900     ovsdb_monitor_json_cache_flush(dbmon);
 901     hmap_destroy(&dbmon->json_cache);
 902
 903     SHASH_FOR_EACH (node, &dbmon->tables) {
 904         struct ovsdb_monitor_table *mt = node->data;
 905         struct ovsdb_monitor_changes *changes, *next;
 906
 907         HMAP_FOR_EACH_SAFE (changes, next, hmap_node, &mt->changes) {
 908             hmap_remove(&mt->changes, &changes->hmap_node);
 909             ovsdb_monitor_changes_destroy(changes);
 910         }
 911         free(mt->columns);
 912         free(mt);
 913     }
 914     shash_destroy(&dbmon->tables);
 915     free(dbmon);
 916 }
 917
 918 static struct ovsdb_error *
 919 ovsdb_monitor_commit(struct ovsdb_replica *replica,
 920                      const struct ovsdb_txn *txn,
 921                      bool durable OVS_UNUSED)
 922 {
 923     struct ovsdb_monitor *m = ovsdb_monitor_cast(replica);
 924     struct ovsdb_monitor_aux aux;
 925
 926     ovsdb_monitor_json_cache_flush(m);
 927     ovsdb_monitor_init_aux(&aux, m);
 928     ovsdb_txn_for_each_change(txn, ovsdb_monitor_change_cb, &aux);
 929     m->n_transactions++;
 930
 931     return NULL;
 932 }
 933
 934 static void
 935 ovsdb_monitor_destroy_callback(struct ovsdb_replica *replica)
 936 {
 937     struct ovsdb_monitor *dbmon = ovsdb_monitor_cast(replica);
 938     struct jsonrpc_monitor_node *jm, *next;
 939
 940     /* Delete all front end monitors. Removing the last front
 941      * end monitor will also destroy the corresponding 'ovsdb_monitor'.
 942      * ovsdb monitor will also be destroied.  */
 943     LIST_FOR_EACH_SAFE(jm, next, node, &dbmon->jsonrpc_monitors) {
 944         ovsdb_jsonrpc_monitor_destroy(jm->jsonrpc_monitor);
 945     }
 946 }
 947
 948 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
 949     ovsdb_monitor_commit,
 950     ovsdb_monitor_destroy_callback,
 951 };