ovsdb/jsonrpc-server.c

   1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 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 #include <config.h>
  17
  18 #include "jsonrpc-server.h"
  19
  20 #include <errno.h>
  21
  22 #include "bitmap.h"
  23 #include "column.h"
  24 #include "dynamic-string.h"
  25 #include "json.h"
  26 #include "jsonrpc.h"
  27 #include "ovsdb-error.h"
  28 #include "ovsdb-parser.h"
  29 #include "ovsdb.h"
  30 #include "poll-loop.h"
  31 #include "reconnect.h"
  32 #include "row.h"
  33 #include "server.h"
  34 #include "simap.h"
  35 #include "stream.h"
  36 #include "table.h"
  37 #include "timeval.h"
  38 #include "transaction.h"
  39 #include "trigger.h"
  40 #include "monitor.h"
  41 #include "openvswitch/vlog.h"
  42
  43 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
  44
  45 struct ovsdb_jsonrpc_remote;
  46 struct ovsdb_jsonrpc_session;
  47
  48 /* Message rate-limiting. */
  49 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  50
  51 /* Sessions. */
  52 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  53     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  54 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  55 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  56 static void ovsdb_jsonrpc_session_get_memory_usage_all(
  57     const struct ovsdb_jsonrpc_remote *, struct simap *usage);
  58 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  59 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  60 static void ovsdb_jsonrpc_session_set_all_options(
  61     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  62 static bool ovsdb_jsonrpc_session_get_status(
  63     const struct ovsdb_jsonrpc_remote *,
  64     struct ovsdb_jsonrpc_remote_status *);
  65 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  66 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  67 static void ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *,
  68                                        struct jsonrpc_msg *);
  69
  70 /* Triggers. */
  71 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  72                                          struct ovsdb *,
  73                                          struct json *id, struct json *params);
  74 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  75     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  76 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  77 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  78 static void ovsdb_jsonrpc_trigger_complete_done(
  79     struct ovsdb_jsonrpc_session *);
  80
  81 /* Monitors. */
  82 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_create(
  83     struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params,
  84     const struct json *request_id);
  85 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  86     struct ovsdb_jsonrpc_session *,
  87     struct json_array *params,
  88     const struct json *request_id);
  89 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
  90 static void ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *);
  91 static bool ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *);
  92 \f
  93 /* JSON-RPC database server. */
  94
  95 struct ovsdb_jsonrpc_server {
  96     struct ovsdb_server up;
  97     unsigned int n_sessions, max_sessions;
  98     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
  99 };
 100
 101 /* A configured remote.  This is either a passive stream listener plus a list
 102  * of the currently connected sessions, or a list of exactly one active
 103  * session. */
 104 struct ovsdb_jsonrpc_remote {
 105     struct ovsdb_jsonrpc_server *server;
 106     struct pstream *listener;   /* Listener, if passive. */
 107     struct ovs_list sessions;   /* List of "struct ovsdb_jsonrpc_session"s. */
 108     uint8_t dscp;
 109 };
 110
 111 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 112     struct ovsdb_jsonrpc_server *, const char *name,
 113     const struct ovsdb_jsonrpc_options *options
 114 );
 115 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 116
 117 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 118  *
 119  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 120  * which 'server' should provide access. */
 121 struct ovsdb_jsonrpc_server *
 122 ovsdb_jsonrpc_server_create(void)
 123 {
 124     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 125     ovsdb_server_init(&server->up);
 126     server->max_sessions = 330;   /* Random limit. */
 127     shash_init(&server->remotes);
 128     return server;
 129 }
 130
 131 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 132  * successful, false if 'db''s name is the same as some database already in
 133  * 'server'. */
 134 bool
 135 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 136 {
 137     /* The OVSDB protocol doesn't have a way to notify a client that a
 138      * database has been added.  If some client tried to use the database
 139      * that we're adding and failed, then forcing it to reconnect seems like
 140      * a reasonable way to make it try again.
 141      *
 142      * If this is too big of a hammer in practice, we could be more selective,
 143      * e.g. disconnect only connections that actually tried to use a database
 144      * with 'db''s name. */
 145     ovsdb_jsonrpc_server_reconnect(svr);
 146
 147     return ovsdb_server_add_db(&svr->up, db);
 148 }
 149
 150 /* Removes 'db' from the set of databases served out by 'svr'.  Returns
 151  * true if successful, false if there is no database associated with 'db'. */
 152 bool
 153 ovsdb_jsonrpc_server_remove_db(struct ovsdb_jsonrpc_server *svr,
 154                                struct ovsdb *db)
 155 {
 156     /* There might be pointers to 'db' from 'svr', such as monitors or
 157      * outstanding transactions.  Disconnect all JSON-RPC connections to avoid
 158      * accesses to freed memory.
 159      *
 160      * If this is too big of a hammer in practice, we could be more selective,
 161      * e.g. disconnect only connections that actually reference 'db'. */
 162     ovsdb_jsonrpc_server_reconnect(svr);
 163
 164     return ovsdb_server_remove_db(&svr->up, db);
 165 }
 166
 167 void
 168 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 169 {
 170     struct shash_node *node, *next;
 171
 172     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 173         ovsdb_jsonrpc_server_del_remote(node);
 174     }
 175     shash_destroy(&svr->remotes);
 176     ovsdb_server_destroy(&svr->up);
 177     free(svr);
 178 }
 179
 180 struct ovsdb_jsonrpc_options *
 181 ovsdb_jsonrpc_default_options(const char *target)
 182 {
 183     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 184     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 185     options->probe_interval = (stream_or_pstream_needs_probes(target)
 186                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 187                                : 0);
 188     return options;
 189 }
 190
 191 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 192  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 193  *
 194  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 195  * "tcp:1.2.3.4". */
 196 void
 197 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 198                                  const struct shash *new_remotes)
 199 {
 200     struct shash_node *node, *next;
 201
 202     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 203         struct ovsdb_jsonrpc_remote *remote = node->data;
 204         struct ovsdb_jsonrpc_options *options
 205             = shash_find_data(new_remotes, node->name);
 206
 207         if (!options) {
 208             VLOG_INFO("%s: remote deconfigured", node->name);
 209             ovsdb_jsonrpc_server_del_remote(node);
 210         } else if (options->dscp != remote->dscp) {
 211             ovsdb_jsonrpc_server_del_remote(node);
 212          }
 213     }
 214     SHASH_FOR_EACH (node, new_remotes) {
 215         const struct ovsdb_jsonrpc_options *options = node->data;
 216         struct ovsdb_jsonrpc_remote *remote;
 217
 218         remote = shash_find_data(&svr->remotes, node->name);
 219         if (!remote) {
 220             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 221             if (!remote) {
 222                 continue;
 223             }
 224         }
 225
 226         ovsdb_jsonrpc_session_set_all_options(remote, options);
 227     }
 228 }
 229
 230 static struct ovsdb_jsonrpc_remote *
 231 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 232                                 const char *name,
 233                                 const struct ovsdb_jsonrpc_options *options)
 234 {
 235     struct ovsdb_jsonrpc_remote *remote;
 236     struct pstream *listener;
 237     int error;
 238
 239     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 240     if (error && error != EAFNOSUPPORT) {
 241         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, ovs_strerror(error));
 242         return NULL;
 243     }
 244
 245     remote = xmalloc(sizeof *remote);
 246     remote->server = svr;
 247     remote->listener = listener;
 248     list_init(&remote->sessions);
 249     remote->dscp = options->dscp;
 250     shash_add(&svr->remotes, name, remote);
 251
 252     if (!listener) {
 253         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true));
 254     }
 255     return remote;
 256 }
 257
 258 static void
 259 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 260 {
 261     struct ovsdb_jsonrpc_remote *remote = node->data;
 262
 263     ovsdb_jsonrpc_session_close_all(remote);
 264     pstream_close(remote->listener);
 265     shash_delete(&remote->server->remotes, node);
 266     free(remote);
 267 }
 268
 269 /* Stores status information for the remote named 'target', which should have
 270  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 271  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 272  * a remote named 'target' or if that remote is an inbound remote that has no
 273  * active connections) returns false.  On failure, 'status' will be zeroed.
 274  */
 275 bool
 276 ovsdb_jsonrpc_server_get_remote_status(
 277     const struct ovsdb_jsonrpc_server *svr, const char *target,
 278     struct ovsdb_jsonrpc_remote_status *status)
 279 {
 280     const struct ovsdb_jsonrpc_remote *remote;
 281
 282     memset(status, 0, sizeof *status);
 283
 284     remote = shash_find_data(&svr->remotes, target);
 285     return remote && ovsdb_jsonrpc_session_get_status(remote, status);
 286 }
 287
 288 void
 289 ovsdb_jsonrpc_server_free_remote_status(
 290     struct ovsdb_jsonrpc_remote_status *status)
 291 {
 292     free(status->locks_held);
 293     free(status->locks_waiting);
 294     free(status->locks_lost);
 295 }
 296
 297 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 298  * reconnect. */
 299 void
 300 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 301 {
 302     struct shash_node *node;
 303
 304     SHASH_FOR_EACH (node, &svr->remotes) {
 305         struct ovsdb_jsonrpc_remote *remote = node->data;
 306
 307         ovsdb_jsonrpc_session_reconnect_all(remote);
 308     }
 309 }
 310
 311 void
 312 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 313 {
 314     struct shash_node *node;
 315
 316     SHASH_FOR_EACH (node, &svr->remotes) {
 317         struct ovsdb_jsonrpc_remote *remote = node->data;
 318
 319         if (remote->listener) {
 320             if (svr->n_sessions < svr->max_sessions) {
 321                 struct stream *stream;
 322                 int error;
 323
 324                 error = pstream_accept(remote->listener, &stream);
 325                 if (!error) {
 326                     struct jsonrpc_session *js;
 327                     js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
 328                                                          remote->dscp);
 329                     ovsdb_jsonrpc_session_create(remote, js);
 330                 } else if (error != EAGAIN) {
 331                     VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 332                                  pstream_get_name(remote->listener),
 333                                  ovs_strerror(error));
 334                 }
 335             } else {
 336                 VLOG_WARN_RL(&rl, "%s: connection exceeded maximum (%d)",
 337                              pstream_get_name(remote->listener),
 338                              svr->max_sessions);
 339             }
 340         }
 341
 342         ovsdb_jsonrpc_session_run_all(remote);
 343     }
 344 }
 345
 346 void
 347 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 348 {
 349     struct shash_node *node;
 350
 351     SHASH_FOR_EACH (node, &svr->remotes) {
 352         struct ovsdb_jsonrpc_remote *remote = node->data;
 353
 354         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 355             pstream_wait(remote->listener);
 356         }
 357
 358         ovsdb_jsonrpc_session_wait_all(remote);
 359     }
 360 }
 361
 362 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 363  * memory_report(). */
 364 void
 365 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 366                                       struct simap *usage)
 367 {
 368     struct shash_node *node;
 369
 370     simap_increase(usage, "sessions", svr->n_sessions);
 371     SHASH_FOR_EACH (node, &svr->remotes) {
 372         struct ovsdb_jsonrpc_remote *remote = node->data;
 373
 374         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 375     }
 376 }
 377 \f
 378 /* JSON-RPC database server session. */
 379
 380 struct ovsdb_jsonrpc_session {
 381     struct ovs_list node;       /* Element in remote's sessions list. */
 382     struct ovsdb_session up;
 383     struct ovsdb_jsonrpc_remote *remote;
 384
 385     /* Triggers. */
 386     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 387
 388     /* Monitors. */
 389     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 390
 391     /* Network connectivity. */
 392     struct jsonrpc_session *js;  /* JSON-RPC session. */
 393     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 394 };
 395
 396 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 397 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 398 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 399 static void ovsdb_jsonrpc_session_get_memory_usage(
 400     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 401 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 402                                              struct jsonrpc_msg *);
 403 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 404                                              struct jsonrpc_msg *);
 405
 406 static struct ovsdb_jsonrpc_session *
 407 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 408                              struct jsonrpc_session *js)
 409 {
 410     struct ovsdb_jsonrpc_session *s;
 411
 412     s = xzalloc(sizeof *s);
 413     ovsdb_session_init(&s->up, &remote->server->up);
 414     s->remote = remote;
 415     list_push_back(&remote->sessions, &s->node);
 416     hmap_init(&s->triggers);
 417     hmap_init(&s->monitors);
 418     s->js = js;
 419     s->js_seqno = jsonrpc_session_get_seqno(js);
 420
 421     remote->server->n_sessions++;
 422
 423     return s;
 424 }
 425
 426 static void
 427 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 428 {
 429     ovsdb_jsonrpc_monitor_remove_all(s);
 430     ovsdb_jsonrpc_session_unlock_all(s);
 431     ovsdb_jsonrpc_trigger_complete_all(s);
 432
 433     hmap_destroy(&s->monitors);
 434     hmap_destroy(&s->triggers);
 435
 436     jsonrpc_session_close(s->js);
 437     list_remove(&s->node);
 438     s->remote->server->n_sessions--;
 439     ovsdb_session_destroy(&s->up);
 440     free(s);
 441 }
 442
 443 static int
 444 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 445 {
 446     jsonrpc_session_run(s->js);
 447     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 448         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 449         ovsdb_jsonrpc_trigger_complete_all(s);
 450         ovsdb_jsonrpc_monitor_remove_all(s);
 451         ovsdb_jsonrpc_session_unlock_all(s);
 452     }
 453
 454     ovsdb_jsonrpc_trigger_complete_done(s);
 455
 456     if (!jsonrpc_session_get_backlog(s->js)) {
 457         struct jsonrpc_msg *msg;
 458
 459         ovsdb_jsonrpc_monitor_flush_all(s);
 460
 461         msg = jsonrpc_session_recv(s->js);
 462         if (msg) {
 463             if (msg->type == JSONRPC_REQUEST) {
 464                 ovsdb_jsonrpc_session_got_request(s, msg);
 465             } else if (msg->type == JSONRPC_NOTIFY) {
 466                 ovsdb_jsonrpc_session_got_notify(s, msg);
 467             } else {
 468                 VLOG_WARN("%s: received unexpected %s message",
 469                           jsonrpc_session_get_name(s->js),
 470                           jsonrpc_msg_type_to_string(msg->type));
 471                 jsonrpc_session_force_reconnect(s->js);
 472                 jsonrpc_msg_destroy(msg);
 473             }
 474         }
 475     }
 476     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 477 }
 478
 479 static void
 480 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 481                                   const struct ovsdb_jsonrpc_options *options)
 482 {
 483     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 484     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 485     jsonrpc_session_set_dscp(session->js, options->dscp);
 486 }
 487
 488 static void
 489 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 490 {
 491     struct ovsdb_jsonrpc_session *s, *next;
 492
 493     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 494         int error = ovsdb_jsonrpc_session_run(s);
 495         if (error) {
 496             ovsdb_jsonrpc_session_close(s);
 497         }
 498     }
 499 }
 500
 501 static void
 502 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 503 {
 504     jsonrpc_session_wait(s->js);
 505     if (!jsonrpc_session_get_backlog(s->js)) {
 506         if (ovsdb_jsonrpc_monitor_needs_flush(s)) {
 507             poll_immediate_wake();
 508         } else {
 509             jsonrpc_session_recv_wait(s->js);
 510         }
 511     }
 512 }
 513
 514 static void
 515 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 516 {
 517     struct ovsdb_jsonrpc_session *s;
 518
 519     LIST_FOR_EACH (s, node, &remote->sessions) {
 520         ovsdb_jsonrpc_session_wait(s);
 521     }
 522 }
 523
 524 static void
 525 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 526                                        struct simap *usage)
 527 {
 528     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 529     simap_increase(usage, "monitors", hmap_count(&s->monitors));
 530     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 531 }
 532
 533 static void
 534 ovsdb_jsonrpc_session_get_memory_usage_all(
 535     const struct ovsdb_jsonrpc_remote *remote,
 536     struct simap *usage)
 537 {
 538     struct ovsdb_jsonrpc_session *s;
 539
 540     LIST_FOR_EACH (s, node, &remote->sessions) {
 541         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 542     }
 543 }
 544
 545 static void
 546 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 547 {
 548     struct ovsdb_jsonrpc_session *s, *next;
 549
 550     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 551         ovsdb_jsonrpc_session_close(s);
 552     }
 553 }
 554
 555 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 556  * reconnect. */
 557 static void
 558 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 559 {
 560     struct ovsdb_jsonrpc_session *s, *next;
 561
 562     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 563         jsonrpc_session_force_reconnect(s->js);
 564         if (!jsonrpc_session_is_alive(s->js)) {
 565             ovsdb_jsonrpc_session_close(s);
 566         }
 567     }
 568 }
 569
 570 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 571  * 'options'.
 572  *
 573  * (The dscp value can't be changed directly; the caller must instead close and
 574  * re-open the session.) */
 575 static void
 576 ovsdb_jsonrpc_session_set_all_options(
 577     struct ovsdb_jsonrpc_remote *remote,
 578     const struct ovsdb_jsonrpc_options *options)
 579 {
 580     struct ovsdb_jsonrpc_session *s;
 581
 582     LIST_FOR_EACH (s, node, &remote->sessions) {
 583         ovsdb_jsonrpc_session_set_options(s, options);
 584     }
 585 }
 586
 587 static bool
 588 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
 589                                  struct ovsdb_jsonrpc_remote_status *status)
 590 {
 591     const struct ovsdb_jsonrpc_session *s;
 592     const struct jsonrpc_session *js;
 593     struct ovsdb_lock_waiter *waiter;
 594     struct reconnect_stats rstats;
 595     struct ds locks_held, locks_waiting, locks_lost;
 596
 597     status->bound_port = (remote->listener
 598                           ? pstream_get_bound_port(remote->listener)
 599                           : htons(0));
 600
 601     if (list_is_empty(&remote->sessions)) {
 602         return false;
 603     }
 604     s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
 605     js = s->js;
 606
 607     status->is_connected = jsonrpc_session_is_connected(js);
 608     status->last_error = jsonrpc_session_get_status(js);
 609
 610     jsonrpc_session_get_reconnect_stats(js, &rstats);
 611     status->state = rstats.state;
 612     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 613         ? UINT_MAX : rstats.msec_since_connect / 1000;
 614     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 615         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 616
 617     ds_init(&locks_held);
 618     ds_init(&locks_waiting);
 619     ds_init(&locks_lost);
 620     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 621         struct ds *string;
 622
 623         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 624                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 625                   : &locks_lost);
 626         if (string->length) {
 627             ds_put_char(string, ' ');
 628         }
 629         ds_put_cstr(string, waiter->lock_name);
 630     }
 631     status->locks_held = ds_steal_cstr(&locks_held);
 632     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 633     status->locks_lost = ds_steal_cstr(&locks_lost);
 634
 635     status->n_connections = list_size(&remote->sessions);
 636
 637     return true;
 638 }
 639
 640 /* Examines 'request' to determine the database to which it relates, and then
 641  * searches 's' to find that database:
 642  *
 643  *    - If successful, returns the database and sets '*replyp' to NULL.
 644  *
 645  *    - If no such database exists, returns NULL and sets '*replyp' to an
 646  *      appropriate JSON-RPC error reply, owned by the caller. */
 647 static struct ovsdb *
 648 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 649                         const struct jsonrpc_msg *request,
 650                         struct jsonrpc_msg **replyp)
 651 {
 652     struct json_array *params;
 653     struct ovsdb_error *error;
 654     const char *db_name;
 655     struct ovsdb *db;
 656
 657     params = json_array(request->params);
 658     if (!params->n || params->elems[0]->type != JSON_STRING) {
 659         error = ovsdb_syntax_error(
 660             request->params, NULL,
 661             "%s request params must begin with <db-name>", request->method);
 662         goto error;
 663     }
 664
 665     db_name = params->elems[0]->u.string;
 666     db = shash_find_data(&s->up.server->dbs, db_name);
 667     if (!db) {
 668         error = ovsdb_syntax_error(
 669             request->params, "unknown database",
 670             "%s request specifies unknown database %s",
 671             request->method, db_name);
 672         goto error;
 673     }
 674
 675     *replyp = NULL;
 676     return db;
 677
 678 error:
 679     *replyp = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 680     ovsdb_error_destroy(error);
 681     return NULL;
 682 }
 683
 684 static struct ovsdb_error *
 685 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 686                                       const char **lock_namep)
 687 {
 688     const struct json_array *params;
 689
 690     params = json_array(request->params);
 691     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 692         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 693         *lock_namep = NULL;
 694         return ovsdb_syntax_error(request->params, NULL,
 695                                   "%s request params must be <id>",
 696                                   request->method);
 697     }
 698
 699     *lock_namep = json_string(params->elems[0]);
 700     return NULL;
 701 }
 702
 703 static void
 704 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 705                              const char *lock_name,
 706                              const char *method)
 707 {
 708     struct ovsdb_jsonrpc_session *s;
 709     struct json *params;
 710
 711     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 712     params = json_array_create_1(json_string_create(lock_name));
 713     ovsdb_jsonrpc_session_send(s, jsonrpc_create_notify(method, params));
 714 }
 715
 716 static struct jsonrpc_msg *
 717 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 718                            struct jsonrpc_msg *request,
 719                            enum ovsdb_lock_mode mode)
 720 {
 721     struct ovsdb_lock_waiter *waiter;
 722     struct jsonrpc_msg *reply;
 723     struct ovsdb_error *error;
 724     struct ovsdb_session *victim;
 725     const char *lock_name;
 726     struct json *result;
 727
 728     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 729     if (error) {
 730         goto error;
 731     }
 732
 733     /* Report error if this session has issued a "lock" or "steal" without a
 734      * matching "unlock" for this lock. */
 735     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 736     if (waiter) {
 737         error = ovsdb_syntax_error(
 738             request->params, NULL,
 739             "must issue \"unlock\" before new \"%s\"", request->method);
 740         goto error;
 741     }
 742
 743     /* Get the lock, add us as a waiter. */
 744     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 745                                &victim);
 746     if (victim) {
 747         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 748     }
 749
 750     result = json_object_create();
 751     json_object_put(result, "locked",
 752                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 753
 754     return jsonrpc_create_reply(result, request->id);
 755
 756 error:
 757     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 758     ovsdb_error_destroy(error);
 759     return reply;
 760 }
 761
 762 static void
 763 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 764 {
 765     struct ovsdb_lock_waiter *waiter, *next;
 766
 767     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 768         ovsdb_jsonrpc_session_unlock__(waiter);
 769     }
 770 }
 771
 772 static void
 773 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 774 {
 775     struct ovsdb_lock *lock = waiter->lock;
 776
 777     if (lock) {
 778         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 779         if (new_owner) {
 780             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 781         } else {
 782             /* ovsdb_server_lock() might have freed 'lock'. */
 783         }
 784     }
 785
 786     ovsdb_lock_waiter_destroy(waiter);
 787 }
 788
 789 static struct jsonrpc_msg *
 790 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 791                              struct jsonrpc_msg *request)
 792 {
 793     struct ovsdb_lock_waiter *waiter;
 794     struct jsonrpc_msg *reply;
 795     struct ovsdb_error *error;
 796     const char *lock_name;
 797
 798     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 799     if (error) {
 800         goto error;
 801     }
 802
 803     /* Report error if this session has not issued a "lock" or "steal" for this
 804      * lock. */
 805     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 806     if (!waiter) {
 807         error = ovsdb_syntax_error(
 808             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 809         goto error;
 810     }
 811
 812     ovsdb_jsonrpc_session_unlock__(waiter);
 813
 814     return jsonrpc_create_reply(json_object_create(), request->id);
 815
 816 error:
 817     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 818     ovsdb_error_destroy(error);
 819     return reply;
 820 }
 821
 822 static struct jsonrpc_msg *
 823 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 824                     struct jsonrpc_msg *request)
 825 {
 826     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 827     request->id = NULL;
 828     request->params = NULL;
 829     jsonrpc_msg_destroy(request);
 830     return NULL;
 831 }
 832
 833 static void
 834 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 835                                   struct jsonrpc_msg *request)
 836 {
 837     struct jsonrpc_msg *reply;
 838
 839     if (!strcmp(request->method, "transact")) {
 840         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 841         if (!reply) {
 842             reply = execute_transaction(s, db, request);
 843         }
 844     } else if (!strcmp(request->method, "monitor")) {
 845         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 846         if (!reply) {
 847             reply = ovsdb_jsonrpc_monitor_create(s, db, request->params,
 848                                                  request->id);
 849         }
 850     } else if (!strcmp(request->method, "monitor_cancel")) {
 851         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 852                                              request->id);
 853     } else if (!strcmp(request->method, "get_schema")) {
 854         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 855         if (!reply) {
 856             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 857                                          request->id);
 858         }
 859     } else if (!strcmp(request->method, "list_dbs")) {
 860         size_t n_dbs = shash_count(&s->up.server->dbs);
 861         struct shash_node *node;
 862         struct json **dbs;
 863         size_t i;
 864
 865         dbs = xmalloc(n_dbs * sizeof *dbs);
 866         i = 0;
 867         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 868             dbs[i++] = json_string_create(node->name);
 869         }
 870         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 871                                      request->id);
 872     } else if (!strcmp(request->method, "lock")) {
 873         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 874     } else if (!strcmp(request->method, "steal")) {
 875         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 876     } else if (!strcmp(request->method, "unlock")) {
 877         reply = ovsdb_jsonrpc_session_unlock(s, request);
 878     } else if (!strcmp(request->method, "echo")) {
 879         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 880     } else {
 881         reply = jsonrpc_create_error(json_string_create("unknown method"),
 882                                      request->id);
 883     }
 884
 885     if (reply) {
 886         jsonrpc_msg_destroy(request);
 887         ovsdb_jsonrpc_session_send(s, reply);
 888     }
 889 }
 890
 891 static void
 892 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 893 {
 894     if (json_array(request->params)->n == 1) {
 895         struct ovsdb_jsonrpc_trigger *t;
 896         struct json *id;
 897
 898         id = request->params->u.array.elems[0];
 899         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 900         if (t) {
 901             ovsdb_jsonrpc_trigger_complete(t);
 902         }
 903     }
 904 }
 905
 906 static void
 907 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 908                                  struct jsonrpc_msg *request)
 909 {
 910     if (!strcmp(request->method, "cancel")) {
 911         execute_cancel(s, request);
 912     }
 913     jsonrpc_msg_destroy(request);
 914 }
 915
 916 static void
 917 ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *s,
 918                            struct jsonrpc_msg *msg)
 919 {
 920     ovsdb_jsonrpc_monitor_flush_all(s);
 921     jsonrpc_session_send(s->js, msg);
 922 }
 923 \f
 924 /* JSON-RPC database server triggers.
 925  *
 926  * (Every transaction is treated as a trigger even if it doesn't actually have
 927  * any "wait" operations.) */
 928
 929 struct ovsdb_jsonrpc_trigger {
 930     struct ovsdb_trigger trigger;
 931     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 932     struct json *id;
 933 };
 934
 935 static void
 936 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 937                              struct json *id, struct json *params)
 938 {
 939     struct ovsdb_jsonrpc_trigger *t;
 940     size_t hash;
 941
 942     /* Check for duplicate ID. */
 943     hash = json_hash(id, 0);
 944     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 945     if (t) {
 946         struct jsonrpc_msg *msg;
 947
 948         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 949                                    id);
 950         ovsdb_jsonrpc_session_send(s, msg);
 951         json_destroy(id);
 952         json_destroy(params);
 953         return;
 954     }
 955
 956     /* Insert into trigger table. */
 957     t = xmalloc(sizeof *t);
 958     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 959     t->id = id;
 960     hmap_insert(&s->triggers, &t->hmap_node, hash);
 961
 962     /* Complete early if possible. */
 963     if (ovsdb_trigger_is_complete(&t->trigger)) {
 964         ovsdb_jsonrpc_trigger_complete(t);
 965     }
 966 }
 967
 968 static struct ovsdb_jsonrpc_trigger *
 969 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 970                            const struct json *id, size_t hash)
 971 {
 972     struct ovsdb_jsonrpc_trigger *t;
 973
 974     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
 975         if (json_equal(t->id, id)) {
 976             return t;
 977         }
 978     }
 979
 980     return NULL;
 981 }
 982
 983 static void
 984 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 985 {
 986     struct ovsdb_jsonrpc_session *s;
 987
 988     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 989
 990     if (jsonrpc_session_is_connected(s->js)) {
 991         struct jsonrpc_msg *reply;
 992         struct json *result;
 993
 994         result = ovsdb_trigger_steal_result(&t->trigger);
 995         if (result) {
 996             reply = jsonrpc_create_reply(result, t->id);
 997         } else {
 998             reply = jsonrpc_create_error(json_string_create("canceled"),
 999                                          t->id);
1000         }
1001         ovsdb_jsonrpc_session_send(s, reply);
1002     }
1003
1004     json_destroy(t->id);
1005     ovsdb_trigger_destroy(&t->trigger);
1006     hmap_remove(&s->triggers, &t->hmap_node);
1007     free(t);
1008 }
1009
1010 static void
1011 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
1012 {
1013     struct ovsdb_jsonrpc_trigger *t, *next;
1014     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
1015         ovsdb_jsonrpc_trigger_complete(t);
1016     }
1017 }
1018
1019 static void
1020 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
1021 {
1022     while (!list_is_empty(&s->up.completions)) {
1023         struct ovsdb_jsonrpc_trigger *t
1024             = CONTAINER_OF(s->up.completions.next,
1025                            struct ovsdb_jsonrpc_trigger, trigger.node);
1026         ovsdb_jsonrpc_trigger_complete(t);
1027     }
1028 }
1029 \f
1030 /* Jsonrpc front end monitor. */
1031 struct ovsdb_jsonrpc_monitor {
1032     struct ovsdb_jsonrpc_session *session;
1033     struct ovsdb *db;
1034     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1035     struct json *monitor_id;
1036     struct ovsdb_monitor *dbmon;
1037 };
1038
1039 static struct ovsdb_jsonrpc_monitor *
1040 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1041                            const struct json *monitor_id)
1042 {
1043     struct ovsdb_jsonrpc_monitor *m;
1044
1045     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1046         if (json_equal(m->monitor_id, monitor_id)) {
1047             return m;
1048         }
1049     }
1050
1051     return NULL;
1052 }
1053
1054 static bool
1055 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1056 {
1057     const struct json *json;
1058
1059     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1060     return json ? json_boolean(json) : default_value;
1061 }
1062
1063 static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
1064 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_monitor *dbmon,
1065                                     const struct ovsdb_table *table,
1066                                     const struct json *monitor_request,
1067                                     size_t *allocated_columns)
1068 {
1069     const struct ovsdb_table_schema *ts = table->schema;
1070     enum ovsdb_monitor_selection select;
1071     const struct json *columns, *select_json;
1072     struct ovsdb_parser parser;
1073     struct ovsdb_error *error;
1074
1075     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1076     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1077     select_json = ovsdb_parser_member(&parser, "select",
1078                                       OP_OBJECT | OP_OPTIONAL);
1079     error = ovsdb_parser_finish(&parser);
1080     if (error) {
1081         return error;
1082     }
1083
1084     if (select_json) {
1085         select = 0;
1086         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1087         if (parse_bool(&parser, "initial", true)) {
1088             select |= OJMS_INITIAL;
1089         }
1090         if (parse_bool(&parser, "insert", true)) {
1091             select |= OJMS_INSERT;
1092         }
1093         if (parse_bool(&parser, "delete", true)) {
1094             select |= OJMS_DELETE;
1095         }
1096         if (parse_bool(&parser, "modify", true)) {
1097             select |= OJMS_MODIFY;
1098         }
1099         error = ovsdb_parser_finish(&parser);
1100         if (error) {
1101             return error;
1102         }
1103     } else {
1104         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1105     }
1106
1107     ovsdb_monitor_table_add_select(dbmon, table, select);
1108     if (columns) {
1109         size_t i;
1110
1111         if (columns->type != JSON_ARRAY) {
1112             return ovsdb_syntax_error(columns, NULL,
1113                                       "array of column names expected");
1114         }
1115
1116         for (i = 0; i < columns->u.array.n; i++) {
1117             const struct ovsdb_column *column;
1118             const char *s;
1119
1120             if (columns->u.array.elems[i]->type != JSON_STRING) {
1121                 return ovsdb_syntax_error(columns, NULL,
1122                                           "array of column names expected");
1123             }
1124
1125             s = columns->u.array.elems[i]->u.string;
1126             column = shash_find_data(&table->schema->columns, s);
1127             if (!column) {
1128                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1129                                           "column name", s);
1130             }
1131             ovsdb_monitor_add_column(dbmon, table, column, select,
1132                                      allocated_columns);
1133         }
1134     } else {
1135         struct shash_node *node;
1136
1137         SHASH_FOR_EACH (node, &ts->columns) {
1138             const struct ovsdb_column *column = node->data;
1139             if (column->index != OVSDB_COL_UUID) {
1140                 ovsdb_monitor_add_column(dbmon, table, column, select,
1141                                          allocated_columns);
1142             }
1143         }
1144     }
1145
1146     return NULL;
1147 }
1148
1149 static struct jsonrpc_msg *
1150 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1151                              struct json *params,
1152                              const struct json *request_id)
1153 {
1154     struct ovsdb_jsonrpc_monitor *m = NULL;
1155     struct json *monitor_id, *monitor_requests;
1156     struct ovsdb_error *error = NULL;
1157     struct shash_node *node;
1158     struct json *json;
1159
1160     if (json_array(params)->n != 3) {
1161         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1162         goto error;
1163     }
1164     monitor_id = params->u.array.elems[1];
1165     monitor_requests = params->u.array.elems[2];
1166     if (monitor_requests->type != JSON_OBJECT) {
1167         error = ovsdb_syntax_error(monitor_requests, NULL,
1168                                    "monitor-requests must be object");
1169         goto error;
1170     }
1171
1172     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1173         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1174         goto error;
1175     }
1176
1177     m = xzalloc(sizeof *m);
1178     m->session = s;
1179     m->db = db;
1180     m->dbmon = ovsdb_monitor_create(db, m);
1181     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1182     m->monitor_id = json_clone(monitor_id);
1183
1184     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1185         const struct ovsdb_table *table;
1186         const char *column_name;
1187         size_t allocated_columns;
1188         const struct json *mr_value;
1189         size_t i;
1190
1191         table = ovsdb_get_table(m->db, node->name);
1192         if (!table) {
1193             error = ovsdb_syntax_error(NULL, NULL,
1194                                        "no table named %s", node->name);
1195             goto error;
1196         }
1197
1198         ovsdb_monitor_add_table(m->dbmon, table);
1199
1200         /* Parse columns. */
1201         mr_value = node->data;
1202         allocated_columns = 0;
1203         if (mr_value->type == JSON_ARRAY) {
1204             const struct json_array *array = &mr_value->u.array;
1205
1206             for (i = 0; i < array->n; i++) {
1207                 error = ovsdb_jsonrpc_parse_monitor_request(
1208                     m->dbmon, table, array->elems[i], &allocated_columns);
1209                 if (error) {
1210                     goto error;
1211                 }
1212             }
1213         } else {
1214             error = ovsdb_jsonrpc_parse_monitor_request(
1215                 m->dbmon, table, mr_value, &allocated_columns);
1216             if (error) {
1217                 goto error;
1218             }
1219         }
1220
1221         column_name = ovsdb_monitor_table_check_duplicates(m->dbmon, table);
1222
1223         if (column_name) {
1224             error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1225                                        "mentioned more than once",
1226                                         column_name);
1227             goto error;
1228         }
1229     }
1230
1231     return jsonrpc_create_reply(ovsdb_monitor_get_initial(m->dbmon),
1232                                 request_id);
1233
1234 error:
1235     if (m) {
1236         ovsdb_jsonrpc_monitor_destroy(m);
1237     }
1238
1239     json = ovsdb_error_to_json(error);
1240     ovsdb_error_destroy(error);
1241     return jsonrpc_create_error(json, request_id);
1242 }
1243
1244 static struct jsonrpc_msg *
1245 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1246                              struct json_array *params,
1247                              const struct json *request_id)
1248 {
1249     if (params->n != 1) {
1250         return jsonrpc_create_error(json_string_create("invalid parameters"),
1251                                     request_id);
1252     } else {
1253         struct ovsdb_jsonrpc_monitor *m;
1254
1255         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1256         if (!m) {
1257             return jsonrpc_create_error(json_string_create("unknown monitor"),
1258                                         request_id);
1259         } else {
1260             ovsdb_jsonrpc_monitor_destroy(m);
1261             return jsonrpc_create_reply(json_object_create(), request_id);
1262         }
1263     }
1264 }
1265
1266 static void
1267 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1268 {
1269     struct ovsdb_jsonrpc_monitor *m, *next;
1270
1271     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1272         ovsdb_jsonrpc_monitor_destroy(m);
1273     }
1274 }
1275
1276 static struct json *
1277 ovsdb_jsonrpc_monitor_compose_table_update(
1278     const struct ovsdb_jsonrpc_monitor *monitor, bool initial)
1279 {
1280     return ovsdb_monitor_compose_table_update(monitor->dbmon, initial);
1281 }
1282
1283 static bool
1284 ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *s)
1285 {
1286     struct ovsdb_jsonrpc_monitor *m;
1287
1288     HMAP_FOR_EACH (m, node, &s->monitors) {
1289         if (ovsdb_monitor_needs_flush(m->dbmon)) {
1290             return true;
1291         }
1292     }
1293
1294     return false;
1295 }
1296
1297 void
1298 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_jsonrpc_monitor *m)
1299 {
1300     json_destroy(m->monitor_id);
1301     hmap_remove(&m->session->monitors, &m->node);
1302     ovsdb_monitor_destroy(m->dbmon);
1303     free(m);
1304 }
1305
1306 static void
1307 ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *s)
1308 {
1309     struct ovsdb_jsonrpc_monitor *m;
1310
1311     HMAP_FOR_EACH (m, node, &s->monitors) {
1312         struct json *json;
1313
1314         json = ovsdb_jsonrpc_monitor_compose_table_update(m, false);
1315         if (json) {
1316             struct jsonrpc_msg *msg;
1317             struct json *params;
1318
1319             params = json_array_create_2(json_clone(m->monitor_id), json);
1320             msg = jsonrpc_create_notify("update", params);
1321             jsonrpc_session_send(s->js, msg);
1322         }
1323     }
1324 }