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 "monitor.h"
  26 #include "json.h"
  27 #include "jsonrpc.h"
  28 #include "ovsdb-error.h"
  29 #include "ovsdb-parser.h"
  30 #include "ovsdb.h"
  31 #include "poll-loop.h"
  32 #include "reconnect.h"
  33 #include "row.h"
  34 #include "server.h"
  35 #include "simap.h"
  36 #include "stream.h"
  37 #include "table.h"
  38 #include "timeval.h"
  39 #include "transaction.h"
  40 #include "trigger.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 /* Set false to defeature monitor2, causing jsonrpc to respond to monitor2
  49  * method with an error.  */
  50 static bool monitor2_enable__ = true;
  51
  52 /* Message rate-limiting. */
  53 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  54
  55 /* Sessions. */
  56 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  57     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  58 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  59 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  60 static void ovsdb_jsonrpc_session_get_memory_usage_all(
  61     const struct ovsdb_jsonrpc_remote *, struct simap *usage);
  62 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  63 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  64 static void ovsdb_jsonrpc_session_set_all_options(
  65     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  66 static bool ovsdb_jsonrpc_active_session_get_status(
  67     const struct ovsdb_jsonrpc_remote *,
  68     struct ovsdb_jsonrpc_remote_status *);
  69 static void ovsdb_jsonrpc_session_get_status(
  70     const struct ovsdb_jsonrpc_session *,
  71     struct ovsdb_jsonrpc_remote_status *);
  72 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  73 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  74 static void ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *,
  75                                        struct jsonrpc_msg *);
  76
  77 /* Triggers. */
  78 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  79                                          struct ovsdb *,
  80                                          struct json *id, struct json *params);
  81 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  82     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  83 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  84 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  85 static void ovsdb_jsonrpc_trigger_complete_done(
  86     struct ovsdb_jsonrpc_session *);
  87
  88 /* Monitors. */
  89 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_create(
  90     struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params,
  91     enum ovsdb_monitor_version, const struct json *request_id);
  92 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  93     struct ovsdb_jsonrpc_session *,
  94     struct json_array *params,
  95     const struct json *request_id);
  96 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
  97 static void ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *);
  98 static bool ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *);
  99 static struct json *ovsdb_jsonrpc_monitor_compose_update(
 100     struct ovsdb_jsonrpc_monitor *monitor, bool initial);
 101
 102 \f
 103 /* JSON-RPC database server. */
 104
 105 struct ovsdb_jsonrpc_server {
 106     struct ovsdb_server up;
 107     unsigned int n_sessions;
 108     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
 109 };
 110
 111 /* A configured remote.  This is either a passive stream listener plus a list
 112  * of the currently connected sessions, or a list of exactly one active
 113  * session. */
 114 struct ovsdb_jsonrpc_remote {
 115     struct ovsdb_jsonrpc_server *server;
 116     struct pstream *listener;   /* Listener, if passive. */
 117     struct ovs_list sessions;   /* List of "struct ovsdb_jsonrpc_session"s. */
 118     uint8_t dscp;
 119 };
 120
 121 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 122     struct ovsdb_jsonrpc_server *, const char *name,
 123     const struct ovsdb_jsonrpc_options *options
 124 );
 125 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 126
 127 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 128  *
 129  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 130  * which 'server' should provide access. */
 131 struct ovsdb_jsonrpc_server *
 132 ovsdb_jsonrpc_server_create(void)
 133 {
 134     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 135     ovsdb_server_init(&server->up);
 136     shash_init(&server->remotes);
 137     return server;
 138 }
 139
 140 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 141  * successful, false if 'db''s name is the same as some database already in
 142  * 'server'. */
 143 bool
 144 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 145 {
 146     /* The OVSDB protocol doesn't have a way to notify a client that a
 147      * database has been added.  If some client tried to use the database
 148      * that we're adding and failed, then forcing it to reconnect seems like
 149      * a reasonable way to make it try again.
 150      *
 151      * If this is too big of a hammer in practice, we could be more selective,
 152      * e.g. disconnect only connections that actually tried to use a database
 153      * with 'db''s name. */
 154     ovsdb_jsonrpc_server_reconnect(svr);
 155
 156     return ovsdb_server_add_db(&svr->up, db);
 157 }
 158
 159 /* Removes 'db' from the set of databases served out by 'svr'.  Returns
 160  * true if successful, false if there is no database associated with 'db'. */
 161 bool
 162 ovsdb_jsonrpc_server_remove_db(struct ovsdb_jsonrpc_server *svr,
 163                                struct ovsdb *db)
 164 {
 165     /* There might be pointers to 'db' from 'svr', such as monitors or
 166      * outstanding transactions.  Disconnect all JSON-RPC connections to avoid
 167      * accesses to freed memory.
 168      *
 169      * If this is too big of a hammer in practice, we could be more selective,
 170      * e.g. disconnect only connections that actually reference 'db'. */
 171     ovsdb_jsonrpc_server_reconnect(svr);
 172
 173     return ovsdb_server_remove_db(&svr->up, db);
 174 }
 175
 176 void
 177 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 178 {
 179     struct shash_node *node, *next;
 180
 181     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 182         ovsdb_jsonrpc_server_del_remote(node);
 183     }
 184     shash_destroy(&svr->remotes);
 185     ovsdb_server_destroy(&svr->up);
 186     free(svr);
 187 }
 188
 189 struct ovsdb_jsonrpc_options *
 190 ovsdb_jsonrpc_default_options(const char *target)
 191 {
 192     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 193     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 194     options->probe_interval = (stream_or_pstream_needs_probes(target)
 195                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 196                                : 0);
 197     return options;
 198 }
 199
 200 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 201  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 202  *
 203  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 204  * "tcp:1.2.3.4". */
 205 void
 206 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 207                                  const struct shash *new_remotes)
 208 {
 209     struct shash_node *node, *next;
 210
 211     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 212         struct ovsdb_jsonrpc_remote *remote = node->data;
 213         struct ovsdb_jsonrpc_options *options
 214             = shash_find_data(new_remotes, node->name);
 215
 216         if (!options) {
 217             VLOG_INFO("%s: remote deconfigured", node->name);
 218             ovsdb_jsonrpc_server_del_remote(node);
 219         } else if (options->dscp != remote->dscp) {
 220             ovsdb_jsonrpc_server_del_remote(node);
 221          }
 222     }
 223     SHASH_FOR_EACH (node, new_remotes) {
 224         const struct ovsdb_jsonrpc_options *options = node->data;
 225         struct ovsdb_jsonrpc_remote *remote;
 226
 227         remote = shash_find_data(&svr->remotes, node->name);
 228         if (!remote) {
 229             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 230             if (!remote) {
 231                 continue;
 232             }
 233         }
 234
 235         ovsdb_jsonrpc_session_set_all_options(remote, options);
 236     }
 237 }
 238
 239 static struct ovsdb_jsonrpc_remote *
 240 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 241                                 const char *name,
 242                                 const struct ovsdb_jsonrpc_options *options)
 243 {
 244     struct ovsdb_jsonrpc_remote *remote;
 245     struct pstream *listener;
 246     int error;
 247
 248     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 249     if (error && error != EAFNOSUPPORT) {
 250         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, ovs_strerror(error));
 251         return NULL;
 252     }
 253
 254     remote = xmalloc(sizeof *remote);
 255     remote->server = svr;
 256     remote->listener = listener;
 257     list_init(&remote->sessions);
 258     remote->dscp = options->dscp;
 259     shash_add(&svr->remotes, name, remote);
 260
 261     if (!listener) {
 262         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true));
 263     }
 264     return remote;
 265 }
 266
 267 static void
 268 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 269 {
 270     struct ovsdb_jsonrpc_remote *remote = node->data;
 271
 272     ovsdb_jsonrpc_session_close_all(remote);
 273     pstream_close(remote->listener);
 274     shash_delete(&remote->server->remotes, node);
 275     free(remote);
 276 }
 277
 278 /* Stores status information for the remote named 'target', which should have
 279  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 280  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 281  * a remote named 'target' or if that remote is an outbound remote that has no
 282  * active connections) returns false.  On failure, 'status' will be zeroed.
 283  */
 284 bool
 285 ovsdb_jsonrpc_server_get_remote_status(
 286     const struct ovsdb_jsonrpc_server *svr, const char *target,
 287     struct ovsdb_jsonrpc_remote_status *status)
 288 {
 289     const struct ovsdb_jsonrpc_remote *remote;
 290
 291     memset(status, 0, sizeof *status);
 292
 293     remote = shash_find_data(&svr->remotes, target);
 294
 295     if (!remote) {
 296         return false;
 297     }
 298
 299     if (remote->listener) {
 300         status->bound_port = pstream_get_bound_port(remote->listener);
 301         status->is_connected = !list_is_empty(&remote->sessions);
 302         status->n_connections = list_size(&remote->sessions);
 303         return true;
 304     }
 305
 306     return ovsdb_jsonrpc_active_session_get_status(remote, status);
 307 }
 308
 309 void
 310 ovsdb_jsonrpc_server_free_remote_status(
 311     struct ovsdb_jsonrpc_remote_status *status)
 312 {
 313     free(status->locks_held);
 314     free(status->locks_waiting);
 315     free(status->locks_lost);
 316 }
 317
 318 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 319  * reconnect. */
 320 void
 321 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 322 {
 323     struct shash_node *node;
 324
 325     SHASH_FOR_EACH (node, &svr->remotes) {
 326         struct ovsdb_jsonrpc_remote *remote = node->data;
 327
 328         ovsdb_jsonrpc_session_reconnect_all(remote);
 329     }
 330 }
 331
 332 void
 333 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 334 {
 335     struct shash_node *node;
 336
 337     SHASH_FOR_EACH (node, &svr->remotes) {
 338         struct ovsdb_jsonrpc_remote *remote = node->data;
 339
 340         if (remote->listener) {
 341             struct stream *stream;
 342             int error;
 343
 344             error = pstream_accept(remote->listener, &stream);
 345             if (!error) {
 346                 struct jsonrpc_session *js;
 347                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
 348                                                      remote->dscp);
 349                 ovsdb_jsonrpc_session_create(remote, js);
 350             } else if (error != EAGAIN) {
 351                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 352                              pstream_get_name(remote->listener),
 353                              ovs_strerror(error));
 354             }
 355         }
 356
 357         ovsdb_jsonrpc_session_run_all(remote);
 358     }
 359 }
 360
 361 void
 362 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 363 {
 364     struct shash_node *node;
 365
 366     SHASH_FOR_EACH (node, &svr->remotes) {
 367         struct ovsdb_jsonrpc_remote *remote = node->data;
 368
 369         if (remote->listener) {
 370             pstream_wait(remote->listener);
 371         }
 372
 373         ovsdb_jsonrpc_session_wait_all(remote);
 374     }
 375 }
 376
 377 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 378  * memory_report(). */
 379 void
 380 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 381                                       struct simap *usage)
 382 {
 383     struct shash_node *node;
 384
 385     simap_increase(usage, "sessions", svr->n_sessions);
 386     SHASH_FOR_EACH (node, &svr->remotes) {
 387         struct ovsdb_jsonrpc_remote *remote = node->data;
 388
 389         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 390     }
 391 }
 392 \f
 393 /* JSON-RPC database server session. */
 394
 395 struct ovsdb_jsonrpc_session {
 396     struct ovs_list node;       /* Element in remote's sessions list. */
 397     struct ovsdb_session up;
 398     struct ovsdb_jsonrpc_remote *remote;
 399
 400     /* Triggers. */
 401     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 402
 403     /* Monitors. */
 404     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 405
 406     /* Network connectivity. */
 407     struct jsonrpc_session *js;  /* JSON-RPC session. */
 408     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 409 };
 410
 411 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 412 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 413 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 414 static void ovsdb_jsonrpc_session_get_memory_usage(
 415     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 416 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 417                                              struct jsonrpc_msg *);
 418 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 419                                              struct jsonrpc_msg *);
 420
 421 static struct ovsdb_jsonrpc_session *
 422 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 423                              struct jsonrpc_session *js)
 424 {
 425     struct ovsdb_jsonrpc_session *s;
 426
 427     s = xzalloc(sizeof *s);
 428     ovsdb_session_init(&s->up, &remote->server->up);
 429     s->remote = remote;
 430     list_push_back(&remote->sessions, &s->node);
 431     hmap_init(&s->triggers);
 432     hmap_init(&s->monitors);
 433     s->js = js;
 434     s->js_seqno = jsonrpc_session_get_seqno(js);
 435
 436     remote->server->n_sessions++;
 437
 438     return s;
 439 }
 440
 441 static void
 442 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 443 {
 444     ovsdb_jsonrpc_monitor_remove_all(s);
 445     ovsdb_jsonrpc_session_unlock_all(s);
 446     ovsdb_jsonrpc_trigger_complete_all(s);
 447
 448     hmap_destroy(&s->monitors);
 449     hmap_destroy(&s->triggers);
 450
 451     jsonrpc_session_close(s->js);
 452     list_remove(&s->node);
 453     s->remote->server->n_sessions--;
 454     ovsdb_session_destroy(&s->up);
 455     free(s);
 456 }
 457
 458 static int
 459 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 460 {
 461     jsonrpc_session_run(s->js);
 462     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 463         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 464         ovsdb_jsonrpc_trigger_complete_all(s);
 465         ovsdb_jsonrpc_monitor_remove_all(s);
 466         ovsdb_jsonrpc_session_unlock_all(s);
 467     }
 468
 469     ovsdb_jsonrpc_trigger_complete_done(s);
 470
 471     if (!jsonrpc_session_get_backlog(s->js)) {
 472         struct jsonrpc_msg *msg;
 473
 474         ovsdb_jsonrpc_monitor_flush_all(s);
 475
 476         msg = jsonrpc_session_recv(s->js);
 477         if (msg) {
 478             if (msg->type == JSONRPC_REQUEST) {
 479                 ovsdb_jsonrpc_session_got_request(s, msg);
 480             } else if (msg->type == JSONRPC_NOTIFY) {
 481                 ovsdb_jsonrpc_session_got_notify(s, msg);
 482             } else {
 483                 VLOG_WARN("%s: received unexpected %s message",
 484                           jsonrpc_session_get_name(s->js),
 485                           jsonrpc_msg_type_to_string(msg->type));
 486                 jsonrpc_session_force_reconnect(s->js);
 487                 jsonrpc_msg_destroy(msg);
 488             }
 489         }
 490     }
 491     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 492 }
 493
 494 static void
 495 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 496                                   const struct ovsdb_jsonrpc_options *options)
 497 {
 498     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 499     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 500     jsonrpc_session_set_dscp(session->js, options->dscp);
 501 }
 502
 503 static void
 504 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 505 {
 506     struct ovsdb_jsonrpc_session *s, *next;
 507
 508     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 509         int error = ovsdb_jsonrpc_session_run(s);
 510         if (error) {
 511             ovsdb_jsonrpc_session_close(s);
 512         }
 513     }
 514 }
 515
 516 static void
 517 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 518 {
 519     jsonrpc_session_wait(s->js);
 520     if (!jsonrpc_session_get_backlog(s->js)) {
 521         if (ovsdb_jsonrpc_monitor_needs_flush(s)) {
 522             poll_immediate_wake();
 523         } else {
 524             jsonrpc_session_recv_wait(s->js);
 525         }
 526     }
 527 }
 528
 529 static void
 530 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 531 {
 532     struct ovsdb_jsonrpc_session *s;
 533
 534     LIST_FOR_EACH (s, node, &remote->sessions) {
 535         ovsdb_jsonrpc_session_wait(s);
 536     }
 537 }
 538
 539 static void
 540 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 541                                        struct simap *usage)
 542 {
 543     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 544     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 545 }
 546
 547 static void
 548 ovsdb_jsonrpc_session_get_memory_usage_all(
 549     const struct ovsdb_jsonrpc_remote *remote,
 550     struct simap *usage)
 551 {
 552     struct ovsdb_jsonrpc_session *s;
 553
 554     LIST_FOR_EACH (s, node, &remote->sessions) {
 555         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 556     }
 557 }
 558
 559 static void
 560 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 561 {
 562     struct ovsdb_jsonrpc_session *s, *next;
 563
 564     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 565         ovsdb_jsonrpc_session_close(s);
 566     }
 567 }
 568
 569 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 570  * reconnect. */
 571 static void
 572 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 573 {
 574     struct ovsdb_jsonrpc_session *s, *next;
 575
 576     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 577         jsonrpc_session_force_reconnect(s->js);
 578         if (!jsonrpc_session_is_alive(s->js)) {
 579             ovsdb_jsonrpc_session_close(s);
 580         }
 581     }
 582 }
 583
 584 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 585  * 'options'.
 586  *
 587  * (The dscp value can't be changed directly; the caller must instead close and
 588  * re-open the session.) */
 589 static void
 590 ovsdb_jsonrpc_session_set_all_options(
 591     struct ovsdb_jsonrpc_remote *remote,
 592     const struct ovsdb_jsonrpc_options *options)
 593 {
 594     struct ovsdb_jsonrpc_session *s;
 595
 596     LIST_FOR_EACH (s, node, &remote->sessions) {
 597         ovsdb_jsonrpc_session_set_options(s, options);
 598     }
 599 }
 600
 601 /* Sets the 'status' of for the 'remote' with an outgoing connection.   */
 602 static bool
 603 ovsdb_jsonrpc_active_session_get_status(
 604     const struct ovsdb_jsonrpc_remote *remote,
 605     struct ovsdb_jsonrpc_remote_status *status)
 606 {
 607     const struct ovs_list *sessions = &remote->sessions;
 608     const struct ovsdb_jsonrpc_session *s;
 609
 610     if (list_is_empty(sessions)) {
 611         return false;
 612     }
 613
 614     ovs_assert(list_is_singleton(sessions));
 615     s = CONTAINER_OF(list_front(sessions), struct ovsdb_jsonrpc_session, node);
 616     ovsdb_jsonrpc_session_get_status(s, status);
 617     status->n_connections = 1;
 618
 619     return true;
 620 }
 621
 622 static void
 623 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_session *session,
 624                                  struct ovsdb_jsonrpc_remote_status *status)
 625 {
 626     const struct ovsdb_jsonrpc_session *s = session;
 627     const struct jsonrpc_session *js;
 628     struct ovsdb_lock_waiter *waiter;
 629     struct reconnect_stats rstats;
 630     struct ds locks_held, locks_waiting, locks_lost;
 631
 632     js = s->js;
 633
 634     status->is_connected = jsonrpc_session_is_connected(js);
 635     status->last_error = jsonrpc_session_get_status(js);
 636
 637     jsonrpc_session_get_reconnect_stats(js, &rstats);
 638     status->state = rstats.state;
 639     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 640         ? UINT_MAX : rstats.msec_since_connect / 1000;
 641     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 642         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 643
 644     ds_init(&locks_held);
 645     ds_init(&locks_waiting);
 646     ds_init(&locks_lost);
 647     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 648         struct ds *string;
 649
 650         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 651                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 652                   : &locks_lost);
 653         if (string->length) {
 654             ds_put_char(string, ' ');
 655         }
 656         ds_put_cstr(string, waiter->lock_name);
 657     }
 658     status->locks_held = ds_steal_cstr(&locks_held);
 659     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 660     status->locks_lost = ds_steal_cstr(&locks_lost);
 661 }
 662
 663 /* Examines 'request' to determine the database to which it relates, and then
 664  * searches 's' to find that database:
 665  *
 666  *    - If successful, returns the database and sets '*replyp' to NULL.
 667  *
 668  *    - If no such database exists, returns NULL and sets '*replyp' to an
 669  *      appropriate JSON-RPC error reply, owned by the caller. */
 670 static struct ovsdb *
 671 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 672                         const struct jsonrpc_msg *request,
 673                         struct jsonrpc_msg **replyp)
 674 {
 675     struct json_array *params;
 676     struct ovsdb_error *error;
 677     const char *db_name;
 678     struct ovsdb *db;
 679
 680     params = json_array(request->params);
 681     if (!params->n || params->elems[0]->type != JSON_STRING) {
 682         error = ovsdb_syntax_error(
 683             request->params, NULL,
 684             "%s request params must begin with <db-name>", request->method);
 685         goto error;
 686     }
 687
 688     db_name = params->elems[0]->u.string;
 689     db = shash_find_data(&s->up.server->dbs, db_name);
 690     if (!db) {
 691         error = ovsdb_syntax_error(
 692             request->params, "unknown database",
 693             "%s request specifies unknown database %s",
 694             request->method, db_name);
 695         goto error;
 696     }
 697
 698     *replyp = NULL;
 699     return db;
 700
 701 error:
 702     *replyp = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 703     ovsdb_error_destroy(error);
 704     return NULL;
 705 }
 706
 707 static struct ovsdb_error *
 708 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 709                                       const char **lock_namep)
 710 {
 711     const struct json_array *params;
 712
 713     params = json_array(request->params);
 714     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 715         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 716         *lock_namep = NULL;
 717         return ovsdb_syntax_error(request->params, NULL,
 718                                   "%s request params must be <id>",
 719                                   request->method);
 720     }
 721
 722     *lock_namep = json_string(params->elems[0]);
 723     return NULL;
 724 }
 725
 726 static void
 727 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 728                              const char *lock_name,
 729                              const char *method)
 730 {
 731     struct ovsdb_jsonrpc_session *s;
 732     struct json *params;
 733
 734     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 735     params = json_array_create_1(json_string_create(lock_name));
 736     ovsdb_jsonrpc_session_send(s, jsonrpc_create_notify(method, params));
 737 }
 738
 739 static struct jsonrpc_msg *
 740 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 741                            struct jsonrpc_msg *request,
 742                            enum ovsdb_lock_mode mode)
 743 {
 744     struct ovsdb_lock_waiter *waiter;
 745     struct jsonrpc_msg *reply;
 746     struct ovsdb_error *error;
 747     struct ovsdb_session *victim;
 748     const char *lock_name;
 749     struct json *result;
 750
 751     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 752     if (error) {
 753         goto error;
 754     }
 755
 756     /* Report error if this session has issued a "lock" or "steal" without a
 757      * matching "unlock" for this lock. */
 758     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 759     if (waiter) {
 760         error = ovsdb_syntax_error(
 761             request->params, NULL,
 762             "must issue \"unlock\" before new \"%s\"", request->method);
 763         goto error;
 764     }
 765
 766     /* Get the lock, add us as a waiter. */
 767     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 768                                &victim);
 769     if (victim) {
 770         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 771     }
 772
 773     result = json_object_create();
 774     json_object_put(result, "locked",
 775                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 776
 777     return jsonrpc_create_reply(result, request->id);
 778
 779 error:
 780     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 781     ovsdb_error_destroy(error);
 782     return reply;
 783 }
 784
 785 static void
 786 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 787 {
 788     struct ovsdb_lock_waiter *waiter, *next;
 789
 790     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 791         ovsdb_jsonrpc_session_unlock__(waiter);
 792     }
 793 }
 794
 795 static void
 796 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 797 {
 798     struct ovsdb_lock *lock = waiter->lock;
 799
 800     if (lock) {
 801         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 802         if (new_owner) {
 803             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 804         } else {
 805             /* ovsdb_server_lock() might have freed 'lock'. */
 806         }
 807     }
 808
 809     ovsdb_lock_waiter_destroy(waiter);
 810 }
 811
 812 static struct jsonrpc_msg *
 813 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 814                              struct jsonrpc_msg *request)
 815 {
 816     struct ovsdb_lock_waiter *waiter;
 817     struct jsonrpc_msg *reply;
 818     struct ovsdb_error *error;
 819     const char *lock_name;
 820
 821     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 822     if (error) {
 823         goto error;
 824     }
 825
 826     /* Report error if this session has not issued a "lock" or "steal" for this
 827      * lock. */
 828     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 829     if (!waiter) {
 830         error = ovsdb_syntax_error(
 831             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 832         goto error;
 833     }
 834
 835     ovsdb_jsonrpc_session_unlock__(waiter);
 836
 837     return jsonrpc_create_reply(json_object_create(), request->id);
 838
 839 error:
 840     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 841     ovsdb_error_destroy(error);
 842     return reply;
 843 }
 844
 845 static struct jsonrpc_msg *
 846 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 847                     struct jsonrpc_msg *request)
 848 {
 849     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 850     request->id = NULL;
 851     request->params = NULL;
 852     jsonrpc_msg_destroy(request);
 853     return NULL;
 854 }
 855
 856 static void
 857 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 858                                   struct jsonrpc_msg *request)
 859 {
 860     struct jsonrpc_msg *reply;
 861
 862     if (!strcmp(request->method, "transact")) {
 863         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 864         if (!reply) {
 865             reply = execute_transaction(s, db, request);
 866         }
 867     } else if (!strcmp(request->method, "monitor") ||
 868                (monitor2_enable__ && !strcmp(request->method, "monitor2"))) {
 869         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 870         if (!reply) {
 871             int l = strlen(request->method) - strlen("monitor");
 872             enum ovsdb_monitor_version version = l ? OVSDB_MONITOR_V2
 873                                                    : OVSDB_MONITOR_V1;
 874             reply = ovsdb_jsonrpc_monitor_create(s, db, request->params,
 875                                                  version, request->id);
 876         }
 877     } else if (!strcmp(request->method, "monitor_cancel")) {
 878         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 879                                              request->id);
 880     } else if (!strcmp(request->method, "get_schema")) {
 881         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 882         if (!reply) {
 883             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 884                                          request->id);
 885         }
 886     } else if (!strcmp(request->method, "list_dbs")) {
 887         size_t n_dbs = shash_count(&s->up.server->dbs);
 888         struct shash_node *node;
 889         struct json **dbs;
 890         size_t i;
 891
 892         dbs = xmalloc(n_dbs * sizeof *dbs);
 893         i = 0;
 894         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 895             dbs[i++] = json_string_create(node->name);
 896         }
 897         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 898                                      request->id);
 899     } else if (!strcmp(request->method, "lock")) {
 900         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 901     } else if (!strcmp(request->method, "steal")) {
 902         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 903     } else if (!strcmp(request->method, "unlock")) {
 904         reply = ovsdb_jsonrpc_session_unlock(s, request);
 905     } else if (!strcmp(request->method, "echo")) {
 906         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 907     } else {
 908         reply = jsonrpc_create_error(json_string_create("unknown method"),
 909                                      request->id);
 910     }
 911
 912     if (reply) {
 913         jsonrpc_msg_destroy(request);
 914         ovsdb_jsonrpc_session_send(s, reply);
 915     }
 916 }
 917
 918 static void
 919 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 920 {
 921     if (json_array(request->params)->n == 1) {
 922         struct ovsdb_jsonrpc_trigger *t;
 923         struct json *id;
 924
 925         id = request->params->u.array.elems[0];
 926         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 927         if (t) {
 928             ovsdb_jsonrpc_trigger_complete(t);
 929         }
 930     }
 931 }
 932
 933 static void
 934 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 935                                  struct jsonrpc_msg *request)
 936 {
 937     if (!strcmp(request->method, "cancel")) {
 938         execute_cancel(s, request);
 939     }
 940     jsonrpc_msg_destroy(request);
 941 }
 942
 943 static void
 944 ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *s,
 945                            struct jsonrpc_msg *msg)
 946 {
 947     ovsdb_jsonrpc_monitor_flush_all(s);
 948     jsonrpc_session_send(s->js, msg);
 949 }
 950 \f
 951 /* JSON-RPC database server triggers.
 952  *
 953  * (Every transaction is treated as a trigger even if it doesn't actually have
 954  * any "wait" operations.) */
 955
 956 struct ovsdb_jsonrpc_trigger {
 957     struct ovsdb_trigger trigger;
 958     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 959     struct json *id;
 960 };
 961
 962 static void
 963 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 964                              struct json *id, struct json *params)
 965 {
 966     struct ovsdb_jsonrpc_trigger *t;
 967     size_t hash;
 968
 969     /* Check for duplicate ID. */
 970     hash = json_hash(id, 0);
 971     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 972     if (t) {
 973         struct jsonrpc_msg *msg;
 974
 975         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 976                                    id);
 977         ovsdb_jsonrpc_session_send(s, msg);
 978         json_destroy(id);
 979         json_destroy(params);
 980         return;
 981     }
 982
 983     /* Insert into trigger table. */
 984     t = xmalloc(sizeof *t);
 985     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 986     t->id = id;
 987     hmap_insert(&s->triggers, &t->hmap_node, hash);
 988
 989     /* Complete early if possible. */
 990     if (ovsdb_trigger_is_complete(&t->trigger)) {
 991         ovsdb_jsonrpc_trigger_complete(t);
 992     }
 993 }
 994
 995 static struct ovsdb_jsonrpc_trigger *
 996 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 997                            const struct json *id, size_t hash)
 998 {
 999     struct ovsdb_jsonrpc_trigger *t;
1000
1001     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
1002         if (json_equal(t->id, id)) {
1003             return t;
1004         }
1005     }
1006
1007     return NULL;
1008 }
1009
1010 static void
1011 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
1012 {
1013     struct ovsdb_jsonrpc_session *s;
1014
1015     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
1016
1017     if (jsonrpc_session_is_connected(s->js)) {
1018         struct jsonrpc_msg *reply;
1019         struct json *result;
1020
1021         result = ovsdb_trigger_steal_result(&t->trigger);
1022         if (result) {
1023             reply = jsonrpc_create_reply(result, t->id);
1024         } else {
1025             reply = jsonrpc_create_error(json_string_create("canceled"),
1026                                          t->id);
1027         }
1028         ovsdb_jsonrpc_session_send(s, reply);
1029     }
1030
1031     json_destroy(t->id);
1032     ovsdb_trigger_destroy(&t->trigger);
1033     hmap_remove(&s->triggers, &t->hmap_node);
1034     free(t);
1035 }
1036
1037 static void
1038 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
1039 {
1040     struct ovsdb_jsonrpc_trigger *t, *next;
1041     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
1042         ovsdb_jsonrpc_trigger_complete(t);
1043     }
1044 }
1045
1046 static void
1047 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
1048 {
1049     while (!list_is_empty(&s->up.completions)) {
1050         struct ovsdb_jsonrpc_trigger *t
1051             = CONTAINER_OF(s->up.completions.next,
1052                            struct ovsdb_jsonrpc_trigger, trigger.node);
1053         ovsdb_jsonrpc_trigger_complete(t);
1054     }
1055 }
1056 \f
1057 /* Jsonrpc front end monitor. */
1058 struct ovsdb_jsonrpc_monitor {
1059     struct ovsdb_jsonrpc_session *session;
1060     struct ovsdb *db;
1061     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1062     struct json *monitor_id;
1063     struct ovsdb_monitor *dbmon;
1064     uint64_t unflushed;         /* The first transaction that has not been
1065                                        flushed to the jsonrpc remote client. */
1066     enum ovsdb_monitor_version version;
1067 };
1068
1069 static struct ovsdb_jsonrpc_monitor *
1070 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1071                            const struct json *monitor_id)
1072 {
1073     struct ovsdb_jsonrpc_monitor *m;
1074
1075     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1076         if (json_equal(m->monitor_id, monitor_id)) {
1077             return m;
1078         }
1079     }
1080
1081     return NULL;
1082 }
1083
1084 static bool
1085 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1086 {
1087     const struct json *json;
1088
1089     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1090     return json ? json_boolean(json) : default_value;
1091 }
1092
1093 static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
1094 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_monitor *dbmon,
1095                                     const struct ovsdb_table *table,
1096                                     const struct json *monitor_request,
1097                                     size_t *allocated_columns)
1098 {
1099     const struct ovsdb_table_schema *ts = table->schema;
1100     enum ovsdb_monitor_selection select;
1101     const struct json *columns, *select_json;
1102     struct ovsdb_parser parser;
1103     struct ovsdb_error *error;
1104
1105     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1106     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1107     select_json = ovsdb_parser_member(&parser, "select",
1108                                       OP_OBJECT | OP_OPTIONAL);
1109     error = ovsdb_parser_finish(&parser);
1110     if (error) {
1111         return error;
1112     }
1113
1114     if (select_json) {
1115         select = 0;
1116         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1117         if (parse_bool(&parser, "initial", true)) {
1118             select |= OJMS_INITIAL;
1119         }
1120         if (parse_bool(&parser, "insert", true)) {
1121             select |= OJMS_INSERT;
1122         }
1123         if (parse_bool(&parser, "delete", true)) {
1124             select |= OJMS_DELETE;
1125         }
1126         if (parse_bool(&parser, "modify", true)) {
1127             select |= OJMS_MODIFY;
1128         }
1129         error = ovsdb_parser_finish(&parser);
1130         if (error) {
1131             return error;
1132         }
1133     } else {
1134         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1135     }
1136
1137     ovsdb_monitor_table_add_select(dbmon, table, select);
1138     if (columns) {
1139         size_t i;
1140
1141         if (columns->type != JSON_ARRAY) {
1142             return ovsdb_syntax_error(columns, NULL,
1143                                       "array of column names expected");
1144         }
1145
1146         for (i = 0; i < columns->u.array.n; i++) {
1147             const struct ovsdb_column *column;
1148             const char *s;
1149
1150             if (columns->u.array.elems[i]->type != JSON_STRING) {
1151                 return ovsdb_syntax_error(columns, NULL,
1152                                           "array of column names expected");
1153             }
1154
1155             s = columns->u.array.elems[i]->u.string;
1156             column = shash_find_data(&table->schema->columns, s);
1157             if (!column) {
1158                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1159                                           "column name", s);
1160             }
1161             ovsdb_monitor_add_column(dbmon, table, column, select,
1162                                      allocated_columns);
1163         }
1164     } else {
1165         struct shash_node *node;
1166
1167         SHASH_FOR_EACH (node, &ts->columns) {
1168             const struct ovsdb_column *column = node->data;
1169             if (column->index != OVSDB_COL_UUID) {
1170                 ovsdb_monitor_add_column(dbmon, table, column, select,
1171                                          allocated_columns);
1172             }
1173         }
1174     }
1175
1176     return NULL;
1177 }
1178
1179 static struct jsonrpc_msg *
1180 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1181                              struct json *params,
1182                              enum ovsdb_monitor_version version,
1183                              const struct json *request_id)
1184 {
1185     struct ovsdb_jsonrpc_monitor *m = NULL;
1186     struct ovsdb_monitor *dbmon = NULL;
1187     struct json *monitor_id, *monitor_requests;
1188     struct ovsdb_error *error = NULL;
1189     struct shash_node *node;
1190     struct json *json;
1191
1192     if (json_array(params)->n != 3) {
1193         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1194         goto error;
1195     }
1196     monitor_id = params->u.array.elems[1];
1197     monitor_requests = params->u.array.elems[2];
1198     if (monitor_requests->type != JSON_OBJECT) {
1199         error = ovsdb_syntax_error(monitor_requests, NULL,
1200                                    "monitor-requests must be object");
1201         goto error;
1202     }
1203
1204     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1205         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1206         goto error;
1207     }
1208
1209     m = xzalloc(sizeof *m);
1210     m->session = s;
1211     m->db = db;
1212     m->dbmon = ovsdb_monitor_create(db, m);
1213     m->unflushed = 0;
1214     m->version = version;
1215     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1216     m->monitor_id = json_clone(monitor_id);
1217
1218     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1219         const struct ovsdb_table *table;
1220         const char *column_name;
1221         size_t allocated_columns;
1222         const struct json *mr_value;
1223         size_t i;
1224
1225         table = ovsdb_get_table(m->db, node->name);
1226         if (!table) {
1227             error = ovsdb_syntax_error(NULL, NULL,
1228                                        "no table named %s", node->name);
1229             goto error;
1230         }
1231
1232         ovsdb_monitor_add_table(m->dbmon, table);
1233
1234         /* Parse columns. */
1235         mr_value = node->data;
1236         allocated_columns = 0;
1237         if (mr_value->type == JSON_ARRAY) {
1238             const struct json_array *array = &mr_value->u.array;
1239
1240             for (i = 0; i < array->n; i++) {
1241                 error = ovsdb_jsonrpc_parse_monitor_request(
1242                     m->dbmon, table, array->elems[i], &allocated_columns);
1243                 if (error) {
1244                     goto error;
1245                 }
1246             }
1247         } else {
1248             error = ovsdb_jsonrpc_parse_monitor_request(
1249                 m->dbmon, table, mr_value, &allocated_columns);
1250             if (error) {
1251                 goto error;
1252             }
1253         }
1254
1255         column_name = ovsdb_monitor_table_check_duplicates(m->dbmon, table);
1256
1257         if (column_name) {
1258             error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1259                                        "mentioned more than once",
1260                                         column_name);
1261             goto error;
1262         }
1263     }
1264
1265     dbmon = ovsdb_monitor_add(m->dbmon);
1266     if (dbmon != m->dbmon) {
1267         /* Found an exisiting dbmon, reuse the current one. */
1268         ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m);
1269         ovsdb_monitor_add_jsonrpc_monitor(dbmon, m);
1270         m->dbmon = dbmon;
1271     }
1272
1273     ovsdb_monitor_get_initial(m->dbmon);
1274     json = ovsdb_jsonrpc_monitor_compose_update(m, true);
1275     json = json ? json : json_object_create();
1276     return jsonrpc_create_reply(json, request_id);
1277
1278 error:
1279     if (m) {
1280         ovsdb_jsonrpc_monitor_destroy(m);
1281     }
1282
1283     json = ovsdb_error_to_json(error);
1284     ovsdb_error_destroy(error);
1285     return jsonrpc_create_error(json, request_id);
1286 }
1287
1288 static struct jsonrpc_msg *
1289 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1290                              struct json_array *params,
1291                              const struct json *request_id)
1292 {
1293     if (params->n != 1) {
1294         return jsonrpc_create_error(json_string_create("invalid parameters"),
1295                                     request_id);
1296     } else {
1297         struct ovsdb_jsonrpc_monitor *m;
1298
1299         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1300         if (!m) {
1301             return jsonrpc_create_error(json_string_create("unknown monitor"),
1302                                         request_id);
1303         } else {
1304             ovsdb_jsonrpc_monitor_destroy(m);
1305             return jsonrpc_create_reply(json_object_create(), request_id);
1306         }
1307     }
1308 }
1309
1310 static void
1311 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1312 {
1313     struct ovsdb_jsonrpc_monitor *m, *next;
1314
1315     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1316         ovsdb_jsonrpc_monitor_destroy(m);
1317     }
1318 }
1319
1320 static struct json *
1321 ovsdb_jsonrpc_monitor_compose_update(struct ovsdb_jsonrpc_monitor *m,
1322                                      bool initial)
1323 {
1324     if (!ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
1325         return NULL;
1326     }
1327
1328     return ovsdb_monitor_get_update(m->dbmon, initial, &m->unflushed,
1329                                     m->version);
1330 }
1331
1332 static bool
1333 ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *s)
1334 {
1335     struct ovsdb_jsonrpc_monitor *m;
1336
1337     HMAP_FOR_EACH (m, node, &s->monitors) {
1338         if (ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
1339             return true;
1340         }
1341     }
1342
1343     return false;
1344 }
1345
1346 void
1347 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_jsonrpc_monitor *m)
1348 {
1349     json_destroy(m->monitor_id);
1350     hmap_remove(&m->session->monitors, &m->node);
1351     ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m);
1352     free(m);
1353 }
1354
1355 static struct jsonrpc_msg *
1356 ovsdb_jsonrpc_create_notify(const struct ovsdb_jsonrpc_monitor *m,
1357                             struct json *params)
1358 {
1359     const char *method;
1360
1361     switch(m->version) {
1362     case OVSDB_MONITOR_V1:
1363         method = "update";
1364         break;
1365     case OVSDB_MONITOR_V2:
1366         method = "update2";
1367         break;
1368     case OVSDB_MONITOR_VERSION_MAX:
1369     default:
1370         OVS_NOT_REACHED();
1371     }
1372
1373     return jsonrpc_create_notify(method, params);
1374 }
1375
1376 static void
1377 ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *s)
1378 {
1379     struct ovsdb_jsonrpc_monitor *m;
1380
1381     HMAP_FOR_EACH (m, node, &s->monitors) {
1382         struct json *json;
1383
1384         json = ovsdb_jsonrpc_monitor_compose_update(m, false);
1385         if (json) {
1386             struct jsonrpc_msg *msg;
1387             struct json *params;
1388
1389             params = json_array_create_2(json_clone(m->monitor_id), json);
1390             msg = ovsdb_jsonrpc_create_notify(m, params);
1391             jsonrpc_session_send(s->js, msg);
1392         }
1393     }
1394 }
1395
1396 void
1397 ovsdb_jsonrpc_disable_monitor2(void)
1398 {
1399     /* Once disabled, it is not possible to re-enable it. */
1400     monitor2_enable__ = false;
1401 }