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 "openvswitch/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 "condition.h"
  32 #include "poll-loop.h"
  33 #include "reconnect.h"
  34 #include "row.h"
  35 #include "server.h"
  36 #include "simap.h"
  37 #include "stream.h"
  38 #include "table.h"
  39 #include "timeval.h"
  40 #include "transaction.h"
  41 #include "trigger.h"
  42 #include "openvswitch/vlog.h"
  43
  44 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
  45
  46 struct ovsdb_jsonrpc_remote;
  47 struct ovsdb_jsonrpc_session;
  48
  49 /* Set false to defeature monitor2, causing jsonrpc to respond to monitor2
  50  * method with an error.  */
  51 static bool monitor2_enable__ = true;
  52
  53 /* Message rate-limiting. */
  54 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  55
  56 /* Sessions. */
  57 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  58     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  59 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  60 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  61 static void ovsdb_jsonrpc_session_get_memory_usage_all(
  62     const struct ovsdb_jsonrpc_remote *, struct simap *usage);
  63 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  64 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  65 static void ovsdb_jsonrpc_session_set_all_options(
  66     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  67 static bool ovsdb_jsonrpc_active_session_get_status(
  68     const struct ovsdb_jsonrpc_remote *,
  69     struct ovsdb_jsonrpc_remote_status *);
  70 static void ovsdb_jsonrpc_session_get_status(
  71     const struct ovsdb_jsonrpc_session *,
  72     struct ovsdb_jsonrpc_remote_status *);
  73 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  74 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  75 static void ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *,
  76                                        struct jsonrpc_msg *);
  77
  78 /* Triggers. */
  79 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  80                                          struct ovsdb *,
  81                                          struct json *id, struct json *params);
  82 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  83     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  84 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  85 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  86 static void ovsdb_jsonrpc_trigger_complete_done(
  87     struct ovsdb_jsonrpc_session *);
  88
  89 /* Monitors. */
  90 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_create(
  91     struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params,
  92     enum ovsdb_monitor_version, const struct json *request_id);
  93 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cond_change(
  94     struct ovsdb_jsonrpc_session *s,
  95     struct json *params,
  96     const struct json *request_id);
  97 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  98     struct ovsdb_jsonrpc_session *,
  99     struct json_array *params,
 100     const struct json *request_id);
 101 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
 102 static void ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *);
 103 static bool ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *);
 104 static struct json *ovsdb_jsonrpc_monitor_compose_update(
 105     struct ovsdb_jsonrpc_monitor *monitor, bool initial);
 106 static struct jsonrpc_msg * ovsdb_jsonrpc_create_notify(
 107                                         const struct ovsdb_jsonrpc_monitor *m,
 108                                         struct json *params);
 109
 110 \f
 111 /* JSON-RPC database server. */
 112
 113 struct ovsdb_jsonrpc_server {
 114     struct ovsdb_server up;
 115     unsigned int n_sessions;
 116     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
 117 };
 118
 119 /* A configured remote.  This is either a passive stream listener plus a list
 120  * of the currently connected sessions, or a list of exactly one active
 121  * session. */
 122 struct ovsdb_jsonrpc_remote {
 123     struct ovsdb_jsonrpc_server *server;
 124     struct pstream *listener;   /* Listener, if passive. */
 125     struct ovs_list sessions;   /* List of "struct ovsdb_jsonrpc_session"s. */
 126     uint8_t dscp;
 127 };
 128
 129 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 130     struct ovsdb_jsonrpc_server *, const char *name,
 131     const struct ovsdb_jsonrpc_options *options
 132 );
 133 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 134
 135 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 136  *
 137  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 138  * which 'server' should provide access. */
 139 struct ovsdb_jsonrpc_server *
 140 ovsdb_jsonrpc_server_create(void)
 141 {
 142     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 143     ovsdb_server_init(&server->up);
 144     shash_init(&server->remotes);
 145     return server;
 146 }
 147
 148 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 149  * successful, false if 'db''s name is the same as some database already in
 150  * 'server'. */
 151 bool
 152 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 153 {
 154     /* The OVSDB protocol doesn't have a way to notify a client that a
 155      * database has been added.  If some client tried to use the database
 156      * that we're adding and failed, then forcing it to reconnect seems like
 157      * a reasonable way to make it try again.
 158      *
 159      * If this is too big of a hammer in practice, we could be more selective,
 160      * e.g. disconnect only connections that actually tried to use a database
 161      * with 'db''s name. */
 162     ovsdb_jsonrpc_server_reconnect(svr);
 163
 164     return ovsdb_server_add_db(&svr->up, db);
 165 }
 166
 167 /* Removes 'db' from the set of databases served out by 'svr'.  Returns
 168  * true if successful, false if there is no database associated with 'db'. */
 169 bool
 170 ovsdb_jsonrpc_server_remove_db(struct ovsdb_jsonrpc_server *svr,
 171                                struct ovsdb *db)
 172 {
 173     /* There might be pointers to 'db' from 'svr', such as monitors or
 174      * outstanding transactions.  Disconnect all JSON-RPC connections to avoid
 175      * accesses to freed memory.
 176      *
 177      * If this is too big of a hammer in practice, we could be more selective,
 178      * e.g. disconnect only connections that actually reference 'db'. */
 179     ovsdb_jsonrpc_server_reconnect(svr);
 180
 181     return ovsdb_server_remove_db(&svr->up, db);
 182 }
 183
 184 void
 185 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 186 {
 187     struct shash_node *node, *next;
 188
 189     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 190         ovsdb_jsonrpc_server_del_remote(node);
 191     }
 192     shash_destroy(&svr->remotes);
 193     ovsdb_server_destroy(&svr->up);
 194     free(svr);
 195 }
 196
 197 struct ovsdb_jsonrpc_options *
 198 ovsdb_jsonrpc_default_options(const char *target)
 199 {
 200     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 201     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 202     options->probe_interval = (stream_or_pstream_needs_probes(target)
 203                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 204                                : 0);
 205     return options;
 206 }
 207
 208 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 209  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 210  *
 211  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 212  * "tcp:1.2.3.4". */
 213 void
 214 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 215                                  const struct shash *new_remotes)
 216 {
 217     struct shash_node *node, *next;
 218
 219     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 220         struct ovsdb_jsonrpc_remote *remote = node->data;
 221         struct ovsdb_jsonrpc_options *options
 222             = shash_find_data(new_remotes, node->name);
 223
 224         if (!options) {
 225             VLOG_INFO("%s: remote deconfigured", node->name);
 226             ovsdb_jsonrpc_server_del_remote(node);
 227         } else if (options->dscp != remote->dscp) {
 228             ovsdb_jsonrpc_server_del_remote(node);
 229          }
 230     }
 231     SHASH_FOR_EACH (node, new_remotes) {
 232         const struct ovsdb_jsonrpc_options *options = node->data;
 233         struct ovsdb_jsonrpc_remote *remote;
 234
 235         remote = shash_find_data(&svr->remotes, node->name);
 236         if (!remote) {
 237             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 238             if (!remote) {
 239                 continue;
 240             }
 241         }
 242
 243         ovsdb_jsonrpc_session_set_all_options(remote, options);
 244     }
 245 }
 246
 247 static struct ovsdb_jsonrpc_remote *
 248 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 249                                 const char *name,
 250                                 const struct ovsdb_jsonrpc_options *options)
 251 {
 252     struct ovsdb_jsonrpc_remote *remote;
 253     struct pstream *listener;
 254     int error;
 255
 256     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 257     if (error && error != EAFNOSUPPORT) {
 258         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, ovs_strerror(error));
 259         return NULL;
 260     }
 261
 262     remote = xmalloc(sizeof *remote);
 263     remote->server = svr;
 264     remote->listener = listener;
 265     ovs_list_init(&remote->sessions);
 266     remote->dscp = options->dscp;
 267     shash_add(&svr->remotes, name, remote);
 268
 269     if (!listener) {
 270         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true));
 271     }
 272     return remote;
 273 }
 274
 275 static void
 276 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 277 {
 278     struct ovsdb_jsonrpc_remote *remote = node->data;
 279
 280     ovsdb_jsonrpc_session_close_all(remote);
 281     pstream_close(remote->listener);
 282     shash_delete(&remote->server->remotes, node);
 283     free(remote);
 284 }
 285
 286 /* Stores status information for the remote named 'target', which should have
 287  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 288  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 289  * a remote named 'target' or if that remote is an outbound remote that has no
 290  * active connections) returns false.  On failure, 'status' will be zeroed.
 291  */
 292 bool
 293 ovsdb_jsonrpc_server_get_remote_status(
 294     const struct ovsdb_jsonrpc_server *svr, const char *target,
 295     struct ovsdb_jsonrpc_remote_status *status)
 296 {
 297     const struct ovsdb_jsonrpc_remote *remote;
 298
 299     memset(status, 0, sizeof *status);
 300
 301     remote = shash_find_data(&svr->remotes, target);
 302
 303     if (!remote) {
 304         return false;
 305     }
 306
 307     if (remote->listener) {
 308         status->bound_port = pstream_get_bound_port(remote->listener);
 309         status->is_connected = !ovs_list_is_empty(&remote->sessions);
 310         status->n_connections = ovs_list_size(&remote->sessions);
 311         return true;
 312     }
 313
 314     return ovsdb_jsonrpc_active_session_get_status(remote, status);
 315 }
 316
 317 void
 318 ovsdb_jsonrpc_server_free_remote_status(
 319     struct ovsdb_jsonrpc_remote_status *status)
 320 {
 321     free(status->locks_held);
 322     free(status->locks_waiting);
 323     free(status->locks_lost);
 324 }
 325
 326 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 327  * reconnect. */
 328 void
 329 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 330 {
 331     struct shash_node *node;
 332
 333     SHASH_FOR_EACH (node, &svr->remotes) {
 334         struct ovsdb_jsonrpc_remote *remote = node->data;
 335
 336         ovsdb_jsonrpc_session_reconnect_all(remote);
 337     }
 338 }
 339
 340 void
 341 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 342 {
 343     struct shash_node *node;
 344
 345     SHASH_FOR_EACH (node, &svr->remotes) {
 346         struct ovsdb_jsonrpc_remote *remote = node->data;
 347
 348         if (remote->listener) {
 349             struct stream *stream;
 350             int error;
 351
 352             error = pstream_accept(remote->listener, &stream);
 353             if (!error) {
 354                 struct jsonrpc_session *js;
 355                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
 356                                                      remote->dscp);
 357                 ovsdb_jsonrpc_session_create(remote, js);
 358             } else if (error != EAGAIN) {
 359                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 360                              pstream_get_name(remote->listener),
 361                              ovs_strerror(error));
 362             }
 363         }
 364
 365         ovsdb_jsonrpc_session_run_all(remote);
 366     }
 367 }
 368
 369 void
 370 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 371 {
 372     struct shash_node *node;
 373
 374     SHASH_FOR_EACH (node, &svr->remotes) {
 375         struct ovsdb_jsonrpc_remote *remote = node->data;
 376
 377         if (remote->listener) {
 378             pstream_wait(remote->listener);
 379         }
 380
 381         ovsdb_jsonrpc_session_wait_all(remote);
 382     }
 383 }
 384
 385 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 386  * memory_report(). */
 387 void
 388 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 389                                       struct simap *usage)
 390 {
 391     struct shash_node *node;
 392
 393     simap_increase(usage, "sessions", svr->n_sessions);
 394     SHASH_FOR_EACH (node, &svr->remotes) {
 395         struct ovsdb_jsonrpc_remote *remote = node->data;
 396
 397         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 398     }
 399 }
 400 \f
 401 /* JSON-RPC database server session. */
 402
 403 struct ovsdb_jsonrpc_session {
 404     struct ovs_list node;       /* Element in remote's sessions list. */
 405     struct ovsdb_session up;
 406     struct ovsdb_jsonrpc_remote *remote;
 407
 408     /* Triggers. */
 409     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 410
 411     /* Monitors. */
 412     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 413
 414     /* Network connectivity. */
 415     struct jsonrpc_session *js;  /* JSON-RPC session. */
 416     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 417 };
 418
 419 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 420 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 421 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 422 static void ovsdb_jsonrpc_session_get_memory_usage(
 423     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 424 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 425                                               struct jsonrpc_msg *);
 426 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 427                                              struct jsonrpc_msg *);
 428
 429 static struct ovsdb_jsonrpc_session *
 430 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 431                              struct jsonrpc_session *js)
 432 {
 433     struct ovsdb_jsonrpc_session *s;
 434
 435     s = xzalloc(sizeof *s);
 436     ovsdb_session_init(&s->up, &remote->server->up);
 437     s->remote = remote;
 438     ovs_list_push_back(&remote->sessions, &s->node);
 439     hmap_init(&s->triggers);
 440     hmap_init(&s->monitors);
 441     s->js = js;
 442     s->js_seqno = jsonrpc_session_get_seqno(js);
 443
 444     remote->server->n_sessions++;
 445
 446     return s;
 447 }
 448
 449 static void
 450 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 451 {
 452     ovsdb_jsonrpc_monitor_remove_all(s);
 453     ovsdb_jsonrpc_session_unlock_all(s);
 454     ovsdb_jsonrpc_trigger_complete_all(s);
 455
 456     hmap_destroy(&s->monitors);
 457     hmap_destroy(&s->triggers);
 458
 459     jsonrpc_session_close(s->js);
 460     ovs_list_remove(&s->node);
 461     s->remote->server->n_sessions--;
 462     ovsdb_session_destroy(&s->up);
 463     free(s);
 464 }
 465
 466 static int
 467 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 468 {
 469     jsonrpc_session_run(s->js);
 470     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 471         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 472         ovsdb_jsonrpc_trigger_complete_all(s);
 473         ovsdb_jsonrpc_monitor_remove_all(s);
 474         ovsdb_jsonrpc_session_unlock_all(s);
 475     }
 476
 477     ovsdb_jsonrpc_trigger_complete_done(s);
 478
 479     if (!jsonrpc_session_get_backlog(s->js)) {
 480         struct jsonrpc_msg *msg;
 481
 482         ovsdb_jsonrpc_monitor_flush_all(s);
 483
 484         msg = jsonrpc_session_recv(s->js);
 485         if (msg) {
 486             if (msg->type == JSONRPC_REQUEST) {
 487                 ovsdb_jsonrpc_session_got_request(s, msg);
 488             } else if (msg->type == JSONRPC_NOTIFY) {
 489                 ovsdb_jsonrpc_session_got_notify(s, msg);
 490             } else {
 491                 VLOG_WARN("%s: received unexpected %s message",
 492                           jsonrpc_session_get_name(s->js),
 493                           jsonrpc_msg_type_to_string(msg->type));
 494                 jsonrpc_session_force_reconnect(s->js);
 495                 jsonrpc_msg_destroy(msg);
 496             }
 497         }
 498     }
 499     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 500 }
 501
 502 static void
 503 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 504                                   const struct ovsdb_jsonrpc_options *options)
 505 {
 506     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 507     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 508     jsonrpc_session_set_dscp(session->js, options->dscp);
 509 }
 510
 511 static void
 512 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 513 {
 514     struct ovsdb_jsonrpc_session *s, *next;
 515
 516     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 517         int error = ovsdb_jsonrpc_session_run(s);
 518         if (error) {
 519             ovsdb_jsonrpc_session_close(s);
 520         }
 521     }
 522 }
 523
 524 static void
 525 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 526 {
 527     jsonrpc_session_wait(s->js);
 528     if (!jsonrpc_session_get_backlog(s->js)) {
 529         if (ovsdb_jsonrpc_monitor_needs_flush(s)) {
 530             poll_immediate_wake();
 531         } else {
 532             jsonrpc_session_recv_wait(s->js);
 533         }
 534     }
 535 }
 536
 537 static void
 538 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 539 {
 540     struct ovsdb_jsonrpc_session *s;
 541
 542     LIST_FOR_EACH (s, node, &remote->sessions) {
 543         ovsdb_jsonrpc_session_wait(s);
 544     }
 545 }
 546
 547 static void
 548 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 549                                        struct simap *usage)
 550 {
 551     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 552     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 553 }
 554
 555 static void
 556 ovsdb_jsonrpc_session_get_memory_usage_all(
 557     const struct ovsdb_jsonrpc_remote *remote,
 558     struct simap *usage)
 559 {
 560     struct ovsdb_jsonrpc_session *s;
 561
 562     LIST_FOR_EACH (s, node, &remote->sessions) {
 563         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 564     }
 565 }
 566
 567 static void
 568 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 569 {
 570     struct ovsdb_jsonrpc_session *s, *next;
 571
 572     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 573         ovsdb_jsonrpc_session_close(s);
 574     }
 575 }
 576
 577 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 578  * reconnect. */
 579 static void
 580 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 581 {
 582     struct ovsdb_jsonrpc_session *s, *next;
 583
 584     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 585         jsonrpc_session_force_reconnect(s->js);
 586         if (!jsonrpc_session_is_alive(s->js)) {
 587             ovsdb_jsonrpc_session_close(s);
 588         }
 589     }
 590 }
 591
 592 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 593  * 'options'.
 594  *
 595  * (The dscp value can't be changed directly; the caller must instead close and
 596  * re-open the session.) */
 597 static void
 598 ovsdb_jsonrpc_session_set_all_options(
 599     struct ovsdb_jsonrpc_remote *remote,
 600     const struct ovsdb_jsonrpc_options *options)
 601 {
 602     struct ovsdb_jsonrpc_session *s;
 603
 604     LIST_FOR_EACH (s, node, &remote->sessions) {
 605         ovsdb_jsonrpc_session_set_options(s, options);
 606     }
 607 }
 608
 609 /* Sets the 'status' of for the 'remote' with an outgoing connection.   */
 610 static bool
 611 ovsdb_jsonrpc_active_session_get_status(
 612     const struct ovsdb_jsonrpc_remote *remote,
 613     struct ovsdb_jsonrpc_remote_status *status)
 614 {
 615     const struct ovs_list *sessions = &remote->sessions;
 616     const struct ovsdb_jsonrpc_session *s;
 617
 618     if (ovs_list_is_empty(sessions)) {
 619         return false;
 620     }
 621
 622     ovs_assert(ovs_list_is_singleton(sessions));
 623     s = CONTAINER_OF(ovs_list_front(sessions), struct ovsdb_jsonrpc_session, node);
 624     ovsdb_jsonrpc_session_get_status(s, status);
 625     status->n_connections = 1;
 626
 627     return true;
 628 }
 629
 630 static void
 631 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_session *session,
 632                                  struct ovsdb_jsonrpc_remote_status *status)
 633 {
 634     const struct ovsdb_jsonrpc_session *s = session;
 635     const struct jsonrpc_session *js;
 636     struct ovsdb_lock_waiter *waiter;
 637     struct reconnect_stats rstats;
 638     struct ds locks_held, locks_waiting, locks_lost;
 639
 640     js = s->js;
 641
 642     status->is_connected = jsonrpc_session_is_connected(js);
 643     status->last_error = jsonrpc_session_get_status(js);
 644
 645     jsonrpc_session_get_reconnect_stats(js, &rstats);
 646     status->state = rstats.state;
 647     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 648         ? UINT_MAX : rstats.msec_since_connect / 1000;
 649     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 650         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 651
 652     ds_init(&locks_held);
 653     ds_init(&locks_waiting);
 654     ds_init(&locks_lost);
 655     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 656         struct ds *string;
 657
 658         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 659                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 660                   : &locks_lost);
 661         if (string->length) {
 662             ds_put_char(string, ' ');
 663         }
 664         ds_put_cstr(string, waiter->lock_name);
 665     }
 666     status->locks_held = ds_steal_cstr(&locks_held);
 667     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 668     status->locks_lost = ds_steal_cstr(&locks_lost);
 669 }
 670
 671 /* Examines 'request' to determine the database to which it relates, and then
 672  * searches 's' to find that database:
 673  *
 674  *    - If successful, returns the database and sets '*replyp' to NULL.
 675  *
 676  *    - If no such database exists, returns NULL and sets '*replyp' to an
 677  *      appropriate JSON-RPC error reply, owned by the caller. */
 678 static struct ovsdb *
 679 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 680                         const struct jsonrpc_msg *request,
 681                         struct jsonrpc_msg **replyp)
 682 {
 683     struct json_array *params;
 684     struct ovsdb_error *error;
 685     const char *db_name;
 686     struct ovsdb *db;
 687
 688     params = json_array(request->params);
 689     if (!params->n || params->elems[0]->type != JSON_STRING) {
 690         error = ovsdb_syntax_error(
 691             request->params, NULL,
 692             "%s request params must begin with <db-name>", request->method);
 693         goto error;
 694     }
 695
 696     db_name = params->elems[0]->u.string;
 697     db = shash_find_data(&s->up.server->dbs, db_name);
 698     if (!db) {
 699         error = ovsdb_syntax_error(
 700             request->params, "unknown database",
 701             "%s request specifies unknown database %s",
 702             request->method, db_name);
 703         goto error;
 704     }
 705
 706     *replyp = NULL;
 707     return db;
 708
 709 error:
 710     *replyp = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 711     ovsdb_error_destroy(error);
 712     return NULL;
 713 }
 714
 715 static struct ovsdb_error *
 716 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 717                                       const char **lock_namep)
 718 {
 719     const struct json_array *params;
 720
 721     params = json_array(request->params);
 722     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 723         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 724         *lock_namep = NULL;
 725         return ovsdb_syntax_error(request->params, NULL,
 726                                   "%s request params must be <id>",
 727                                   request->method);
 728     }
 729
 730     *lock_namep = json_string(params->elems[0]);
 731     return NULL;
 732 }
 733
 734 static void
 735 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 736                              const char *lock_name,
 737                              const char *method)
 738 {
 739     struct ovsdb_jsonrpc_session *s;
 740     struct json *params;
 741
 742     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 743     params = json_array_create_1(json_string_create(lock_name));
 744     ovsdb_jsonrpc_session_send(s, jsonrpc_create_notify(method, params));
 745 }
 746
 747 static struct jsonrpc_msg *
 748 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 749                            struct jsonrpc_msg *request,
 750                            enum ovsdb_lock_mode mode)
 751 {
 752     struct ovsdb_lock_waiter *waiter;
 753     struct jsonrpc_msg *reply;
 754     struct ovsdb_error *error;
 755     struct ovsdb_session *victim;
 756     const char *lock_name;
 757     struct json *result;
 758
 759     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 760     if (error) {
 761         goto error;
 762     }
 763
 764     /* Report error if this session has issued a "lock" or "steal" without a
 765      * matching "unlock" for this lock. */
 766     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 767     if (waiter) {
 768         error = ovsdb_syntax_error(
 769             request->params, NULL,
 770             "must issue \"unlock\" before new \"%s\"", request->method);
 771         goto error;
 772     }
 773
 774     /* Get the lock, add us as a waiter. */
 775     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 776                                &victim);
 777     if (victim) {
 778         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 779     }
 780
 781     result = json_object_create();
 782     json_object_put(result, "locked",
 783                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 784
 785     return jsonrpc_create_reply(result, request->id);
 786
 787 error:
 788     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 789     ovsdb_error_destroy(error);
 790     return reply;
 791 }
 792
 793 static void
 794 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 795 {
 796     struct ovsdb_lock_waiter *waiter, *next;
 797
 798     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 799         ovsdb_jsonrpc_session_unlock__(waiter);
 800     }
 801 }
 802
 803 static void
 804 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 805 {
 806     struct ovsdb_lock *lock = waiter->lock;
 807
 808     if (lock) {
 809         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 810         if (new_owner) {
 811             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 812         } else {
 813             /* ovsdb_server_lock() might have freed 'lock'. */
 814         }
 815     }
 816
 817     ovsdb_lock_waiter_destroy(waiter);
 818 }
 819
 820 static struct jsonrpc_msg *
 821 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 822                              struct jsonrpc_msg *request)
 823 {
 824     struct ovsdb_lock_waiter *waiter;
 825     struct jsonrpc_msg *reply;
 826     struct ovsdb_error *error;
 827     const char *lock_name;
 828
 829     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 830     if (error) {
 831         goto error;
 832     }
 833
 834     /* Report error if this session has not issued a "lock" or "steal" for this
 835      * lock. */
 836     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 837     if (!waiter) {
 838         error = ovsdb_syntax_error(
 839             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 840         goto error;
 841     }
 842
 843     ovsdb_jsonrpc_session_unlock__(waiter);
 844
 845     return jsonrpc_create_reply(json_object_create(), request->id);
 846
 847 error:
 848     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 849     ovsdb_error_destroy(error);
 850     return reply;
 851 }
 852
 853 static struct jsonrpc_msg *
 854 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 855                     struct jsonrpc_msg *request)
 856 {
 857     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 858     request->id = NULL;
 859     request->params = NULL;
 860     jsonrpc_msg_destroy(request);
 861     return NULL;
 862 }
 863
 864 static void
 865 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 866                                   struct jsonrpc_msg *request)
 867 {
 868     struct jsonrpc_msg *reply;
 869
 870     if (!strcmp(request->method, "transact")) {
 871         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 872         if (!reply) {
 873             reply = execute_transaction(s, db, request);
 874         }
 875     } else if (!strcmp(request->method, "monitor") ||
 876                (monitor2_enable__ && !strcmp(request->method, "monitor2")) ||
 877                !strcmp(request->method, "monitor_cond")) {
 878         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 879         if (!reply) {
 880             int l = strlen(request->method) - strlen("monitor");
 881             enum ovsdb_monitor_version version = l ? OVSDB_MONITOR_V2
 882                                                    : OVSDB_MONITOR_V1;
 883             reply = ovsdb_jsonrpc_monitor_create(s, db, request->params,
 884                                                  version, request->id);
 885         }
 886     } else if (!strcmp(request->method, "monitor_cond_change")) {
 887         reply = ovsdb_jsonrpc_monitor_cond_change(s, request->params,
 888                                                   request->id);
 889     } else if (!strcmp(request->method, "monitor_cancel")) {
 890         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 891                                              request->id);
 892     } else if (!strcmp(request->method, "get_schema")) {
 893         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 894         if (!reply) {
 895             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 896                                          request->id);
 897         }
 898     } else if (!strcmp(request->method, "list_dbs")) {
 899         size_t n_dbs = shash_count(&s->up.server->dbs);
 900         struct shash_node *node;
 901         struct json **dbs;
 902         size_t i;
 903
 904         dbs = xmalloc(n_dbs * sizeof *dbs);
 905         i = 0;
 906         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 907             dbs[i++] = json_string_create(node->name);
 908         }
 909         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 910                                      request->id);
 911     } else if (!strcmp(request->method, "lock")) {
 912         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 913     } else if (!strcmp(request->method, "steal")) {
 914         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 915     } else if (!strcmp(request->method, "unlock")) {
 916         reply = ovsdb_jsonrpc_session_unlock(s, request);
 917     } else if (!strcmp(request->method, "echo")) {
 918         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 919     } else {
 920         reply = jsonrpc_create_error(json_string_create("unknown method"),
 921                                      request->id);
 922     }
 923
 924     if (reply) {
 925         jsonrpc_msg_destroy(request);
 926         ovsdb_jsonrpc_session_send(s, reply);
 927     }
 928 }
 929
 930 static void
 931 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 932 {
 933     if (json_array(request->params)->n == 1) {
 934         struct ovsdb_jsonrpc_trigger *t;
 935         struct json *id;
 936
 937         id = request->params->u.array.elems[0];
 938         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 939         if (t) {
 940             ovsdb_jsonrpc_trigger_complete(t);
 941         }
 942     }
 943 }
 944
 945 static void
 946 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 947                                  struct jsonrpc_msg *request)
 948 {
 949     if (!strcmp(request->method, "cancel")) {
 950         execute_cancel(s, request);
 951     }
 952     jsonrpc_msg_destroy(request);
 953 }
 954
 955 static void
 956 ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *s,
 957                            struct jsonrpc_msg *msg)
 958 {
 959     ovsdb_jsonrpc_monitor_flush_all(s);
 960     jsonrpc_session_send(s->js, msg);
 961 }
 962 \f
 963 /* JSON-RPC database server triggers.
 964  *
 965  * (Every transaction is treated as a trigger even if it doesn't actually have
 966  * any "wait" operations.) */
 967
 968 struct ovsdb_jsonrpc_trigger {
 969     struct ovsdb_trigger trigger;
 970     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 971     struct json *id;
 972 };
 973
 974 static void
 975 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 976                              struct json *id, struct json *params)
 977 {
 978     struct ovsdb_jsonrpc_trigger *t;
 979     size_t hash;
 980
 981     /* Check for duplicate ID. */
 982     hash = json_hash(id, 0);
 983     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 984     if (t) {
 985         struct jsonrpc_msg *msg;
 986
 987         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 988                                    id);
 989         ovsdb_jsonrpc_session_send(s, msg);
 990         json_destroy(id);
 991         json_destroy(params);
 992         return;
 993     }
 994
 995     /* Insert into trigger table. */
 996     t = xmalloc(sizeof *t);
 997     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 998     t->id = id;
 999     hmap_insert(&s->triggers, &t->hmap_node, hash);
1000
1001     /* Complete early if possible. */
1002     if (ovsdb_trigger_is_complete(&t->trigger)) {
1003         ovsdb_jsonrpc_trigger_complete(t);
1004     }
1005 }
1006
1007 static struct ovsdb_jsonrpc_trigger *
1008 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
1009                            const struct json *id, size_t hash)
1010 {
1011     struct ovsdb_jsonrpc_trigger *t;
1012
1013     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
1014         if (json_equal(t->id, id)) {
1015             return t;
1016         }
1017     }
1018
1019     return NULL;
1020 }
1021
1022 static void
1023 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
1024 {
1025     struct ovsdb_jsonrpc_session *s;
1026
1027     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
1028
1029     if (jsonrpc_session_is_connected(s->js)) {
1030         struct jsonrpc_msg *reply;
1031         struct json *result;
1032
1033         result = ovsdb_trigger_steal_result(&t->trigger);
1034         if (result) {
1035             reply = jsonrpc_create_reply(result, t->id);
1036         } else {
1037             reply = jsonrpc_create_error(json_string_create("canceled"),
1038                                          t->id);
1039         }
1040         ovsdb_jsonrpc_session_send(s, reply);
1041     }
1042
1043     json_destroy(t->id);
1044     ovsdb_trigger_destroy(&t->trigger);
1045     hmap_remove(&s->triggers, &t->hmap_node);
1046     free(t);
1047 }
1048
1049 static void
1050 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
1051 {
1052     struct ovsdb_jsonrpc_trigger *t, *next;
1053     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
1054         ovsdb_jsonrpc_trigger_complete(t);
1055     }
1056 }
1057
1058 static void
1059 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
1060 {
1061     while (!ovs_list_is_empty(&s->up.completions)) {
1062         struct ovsdb_jsonrpc_trigger *t
1063             = CONTAINER_OF(s->up.completions.next,
1064                            struct ovsdb_jsonrpc_trigger, trigger.node);
1065         ovsdb_jsonrpc_trigger_complete(t);
1066     }
1067 }
1068 \f
1069 /* Jsonrpc front end monitor. */
1070 struct ovsdb_jsonrpc_monitor {
1071     struct ovsdb_jsonrpc_session *session;
1072     struct ovsdb *db;
1073     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1074     struct json *monitor_id;
1075     struct ovsdb_monitor *dbmon;
1076     uint64_t unflushed;         /* The first transaction that has not been
1077                                        flushed to the jsonrpc remote client. */
1078     enum ovsdb_monitor_version version;
1079     struct ovsdb_monitor_session_condition *condition;/* Session's condition */
1080 };
1081
1082 static struct ovsdb_jsonrpc_monitor *
1083 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1084                            const struct json *monitor_id)
1085 {
1086     struct ovsdb_jsonrpc_monitor *m;
1087
1088     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1089         if (json_equal(m->monitor_id, monitor_id)) {
1090             return m;
1091         }
1092     }
1093
1094     return NULL;
1095 }
1096
1097 static bool
1098 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1099 {
1100     const struct json *json;
1101
1102     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1103     return json ? json_boolean(json) : default_value;
1104 }
1105
1106 static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
1107 ovsdb_jsonrpc_parse_monitor_request(
1108                                struct ovsdb_monitor *dbmon,
1109                                const struct ovsdb_table *table,
1110                                struct ovsdb_monitor_session_condition *cond,
1111                                const struct json *monitor_request)
1112 {
1113     const struct ovsdb_table_schema *ts = table->schema;
1114     enum ovsdb_monitor_selection select;
1115     const struct json *columns, *select_json, *where = NULL;
1116     struct ovsdb_parser parser;
1117     struct ovsdb_error *error;
1118
1119     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1120     if (cond) {
1121         where = ovsdb_parser_member(&parser, "where", OP_ARRAY | OP_OPTIONAL);
1122     }
1123     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1124
1125     select_json = ovsdb_parser_member(&parser, "select",
1126                                       OP_OBJECT | OP_OPTIONAL);
1127
1128     error = ovsdb_parser_finish(&parser);
1129     if (error) {
1130         return error;
1131     }
1132
1133     if (select_json) {
1134         select = 0;
1135         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1136         if (parse_bool(&parser, "initial", true)) {
1137             select |= OJMS_INITIAL;
1138         }
1139         if (parse_bool(&parser, "insert", true)) {
1140             select |= OJMS_INSERT;
1141         }
1142         if (parse_bool(&parser, "delete", true)) {
1143             select |= OJMS_DELETE;
1144         }
1145         if (parse_bool(&parser, "modify", true)) {
1146             select |= OJMS_MODIFY;
1147         }
1148         error = ovsdb_parser_finish(&parser);
1149         if (error) {
1150             return error;
1151         }
1152     } else {
1153         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1154     }
1155
1156     ovsdb_monitor_table_add_select(dbmon, table, select);
1157     if (columns) {
1158         size_t i;
1159
1160         if (columns->type != JSON_ARRAY) {
1161             return ovsdb_syntax_error(columns, NULL,
1162                                       "array of column names expected");
1163         }
1164
1165         for (i = 0; i < columns->u.array.n; i++) {
1166             const struct ovsdb_column *column;
1167             const char *s;
1168
1169             if (columns->u.array.elems[i]->type != JSON_STRING) {
1170                 return ovsdb_syntax_error(columns, NULL,
1171                                           "array of column names expected");
1172             }
1173
1174             s = columns->u.array.elems[i]->u.string;
1175             column = shash_find_data(&table->schema->columns, s);
1176             if (!column) {
1177                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1178                                           "column name", s);
1179             }
1180             if (ovsdb_monitor_add_column(dbmon, table, column,
1181                                          select, true)) {
1182                 return ovsdb_syntax_error(columns, NULL, "column %s "
1183                                           "mentioned more than once",
1184                                           column->name);
1185             }
1186         }
1187     } else {
1188         struct shash_node *node;
1189
1190         SHASH_FOR_EACH (node, &ts->columns) {
1191             const struct ovsdb_column *column = node->data;
1192             if (column->index != OVSDB_COL_UUID) {
1193                 if (ovsdb_monitor_add_column(dbmon, table, column,
1194                                              select, true)) {
1195                     return ovsdb_syntax_error(columns, NULL, "column %s "
1196                                               "mentioned more than once",
1197                                               column->name);
1198                 }
1199             }
1200         }
1201     }
1202     if (cond) {
1203         error = ovsdb_monitor_table_condition_create(cond, table, where);
1204         if (error) {
1205             return error;
1206         }
1207     }
1208
1209     return NULL;
1210 }
1211
1212 static struct jsonrpc_msg *
1213 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1214                              struct json *params,
1215                              enum ovsdb_monitor_version version,
1216                              const struct json *request_id)
1217 {
1218     struct ovsdb_jsonrpc_monitor *m = NULL;
1219     struct ovsdb_monitor *dbmon = NULL;
1220     struct json *monitor_id, *monitor_requests;
1221     struct ovsdb_error *error = NULL;
1222     struct shash_node *node;
1223     struct json *json;
1224
1225     if (json_array(params)->n != 3) {
1226         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1227         goto error;
1228     }
1229     monitor_id = params->u.array.elems[1];
1230     monitor_requests = params->u.array.elems[2];
1231     if (monitor_requests->type != JSON_OBJECT) {
1232         error = ovsdb_syntax_error(monitor_requests, NULL,
1233                                    "monitor-requests must be object");
1234         goto error;
1235     }
1236
1237     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1238         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1239         goto error;
1240     }
1241
1242     m = xzalloc(sizeof *m);
1243     m->session = s;
1244     m->db = db;
1245     m->dbmon = ovsdb_monitor_create(db, m);
1246     if (version == OVSDB_MONITOR_V2) {
1247         m->condition = ovsdb_monitor_session_condition_create();
1248     }
1249     m->unflushed = 0;
1250     m->version = version;
1251     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1252     m->monitor_id = json_clone(monitor_id);
1253
1254     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1255         const struct ovsdb_table *table;
1256         const struct json *mr_value;
1257         size_t i;
1258
1259         table = ovsdb_get_table(m->db, node->name);
1260         if (!table) {
1261             error = ovsdb_syntax_error(NULL, NULL,
1262                                        "no table named %s", node->name);
1263             goto error;
1264         }
1265
1266         ovsdb_monitor_add_table(m->dbmon, table);
1267
1268         /* Parse columns. */
1269         mr_value = node->data;
1270         if (mr_value->type == JSON_ARRAY) {
1271             const struct json_array *array = &mr_value->u.array;
1272
1273             for (i = 0; i < array->n; i++) {
1274                 error = ovsdb_jsonrpc_parse_monitor_request(m->dbmon,
1275                                                             table,
1276                                                             m->condition,
1277                                                             array->elems[i]);
1278                 if (error) {
1279                     goto error;
1280                 }
1281             }
1282         } else {
1283             error = ovsdb_jsonrpc_parse_monitor_request(m->dbmon,
1284                                                         table,
1285                                                         m->condition,
1286                                                         mr_value);
1287             if (error) {
1288                 goto error;
1289             }
1290         }
1291     }
1292
1293     dbmon = ovsdb_monitor_add(m->dbmon);
1294     if (dbmon != m->dbmon) {
1295         /* Found an exisiting dbmon, reuse the current one. */
1296         ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m, m->unflushed);
1297         ovsdb_monitor_add_jsonrpc_monitor(dbmon, m);
1298         m->dbmon = dbmon;
1299     }
1300
1301     /* Only now we can bind session's condition to ovsdb_monitor */
1302     if (m->condition) {
1303         ovsdb_monitor_condition_bind(m->dbmon, m->condition);
1304     }
1305
1306     ovsdb_monitor_get_initial(m->dbmon);
1307     json = ovsdb_jsonrpc_monitor_compose_update(m, true);
1308     json = json ? json : json_object_create();
1309     return jsonrpc_create_reply(json, request_id);
1310
1311 error:
1312     if (m) {
1313         ovsdb_jsonrpc_monitor_destroy(m);
1314     }
1315
1316     json = ovsdb_error_to_json(error);
1317     ovsdb_error_destroy(error);
1318     return jsonrpc_create_error(json, request_id);
1319 }
1320
1321 static struct ovsdb_error *
1322 ovsdb_jsonrpc_parse_monitor_cond_change_request(
1323                                 struct ovsdb_jsonrpc_monitor *m,
1324                                 const struct ovsdb_table *table,
1325                                 const struct json *cond_change_req)
1326 {
1327     const struct ovsdb_table_schema *ts = table->schema;
1328     const struct json *condition, *columns;
1329     struct ovsdb_parser parser;
1330     struct ovsdb_error *error;
1331
1332     ovsdb_parser_init(&parser, cond_change_req, "table %s", ts->name);
1333     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1334     condition = ovsdb_parser_member(&parser, "where", OP_ARRAY | OP_OPTIONAL);
1335
1336     error = ovsdb_parser_finish(&parser);
1337     if (error) {
1338         return error;
1339     }
1340
1341     if (columns) {
1342         error = ovsdb_syntax_error(cond_change_req, NULL, "changing columns "
1343                                    "is unsupported");
1344         return error;
1345     }
1346     error = ovsdb_monitor_table_condition_update(m->dbmon, m->condition, table,
1347                                                  condition);
1348
1349     return error;
1350 }
1351
1352 static struct jsonrpc_msg *
1353 ovsdb_jsonrpc_monitor_cond_change(struct ovsdb_jsonrpc_session *s,
1354                                   struct json *params,
1355                                   const struct json *request_id)
1356 {
1357     struct ovsdb_error *error;
1358     struct ovsdb_jsonrpc_monitor *m;
1359     struct json *monitor_cond_change_reqs;
1360     struct shash_node *node;
1361     struct json *json;
1362
1363     if (json_array(params)->n != 3) {
1364         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1365         goto error;
1366     }
1367
1368     m = ovsdb_jsonrpc_monitor_find(s, params->u.array.elems[0]);
1369     if (!m) {
1370         error = ovsdb_syntax_error(request_id, NULL,
1371                                    "unknown monitor session");
1372         goto error;
1373     }
1374
1375     monitor_cond_change_reqs = params->u.array.elems[2];
1376     if (monitor_cond_change_reqs->type != JSON_OBJECT) {
1377         error =
1378             ovsdb_syntax_error(NULL, NULL,
1379                                "monitor-cond-change-requests must be object");
1380         goto error;
1381     }
1382
1383     SHASH_FOR_EACH (node, json_object(monitor_cond_change_reqs)) {
1384         const struct ovsdb_table *table;
1385         const struct json *mr_value;
1386         size_t i;
1387
1388         table = ovsdb_get_table(m->db, node->name);
1389         if (!table) {
1390             error = ovsdb_syntax_error(NULL, NULL,
1391                                        "no table named %s", node->name);
1392             goto error;
1393         }
1394         if (!ovsdb_monitor_table_exists(m->dbmon, table)) {
1395             error = ovsdb_syntax_error(NULL, NULL,
1396                                        "no table named %s in monitor session",
1397                                        node->name);
1398             goto error;
1399         }
1400
1401         mr_value = node->data;
1402         if (mr_value->type == JSON_ARRAY) {
1403             const struct json_array *array = &mr_value->u.array;
1404
1405             for (i = 0; i < array->n; i++) {
1406                 error = ovsdb_jsonrpc_parse_monitor_cond_change_request(
1407                                             m, table, array->elems[i]);
1408                 if (error) {
1409                     goto error;
1410                 }
1411             }
1412         } else {
1413             error = ovsdb_syntax_error(
1414                        NULL, NULL,
1415                        "table %s no monitor-cond-change JSON array",
1416                        node->name);
1417             goto error;
1418         }
1419     }
1420
1421     /* Change monitor id */
1422     hmap_remove(&s->monitors, &m->node);
1423     json_destroy(m->monitor_id);
1424     m->monitor_id = json_clone(params->u.array.elems[1]);
1425     hmap_insert(&s->monitors, &m->node, json_hash(m->monitor_id, 0));
1426
1427     /* Send the new update, if any,  represents the difference from the old
1428      * condition and the new one. */
1429     struct json *update_json;
1430
1431     update_json = ovsdb_monitor_get_update(m->dbmon, false, true,
1432                                     &m->unflushed, m->condition, m->version);
1433     if (update_json) {
1434         struct jsonrpc_msg *msg;
1435         struct json *params;
1436
1437         params = json_array_create_2(json_clone(m->monitor_id), update_json);
1438         msg = ovsdb_jsonrpc_create_notify(m, params);
1439         jsonrpc_session_send(s->js, msg);
1440     }
1441
1442     return jsonrpc_create_reply(json_object_create(), request_id);
1443
1444 error:
1445
1446     json = ovsdb_error_to_json(error);
1447     ovsdb_error_destroy(error);
1448     return jsonrpc_create_error(json, request_id);
1449 }
1450
1451 static struct jsonrpc_msg *
1452 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1453                              struct json_array *params,
1454                              const struct json *request_id)
1455 {
1456     if (params->n != 1) {
1457         return jsonrpc_create_error(json_string_create("invalid parameters"),
1458                                     request_id);
1459     } else {
1460         struct ovsdb_jsonrpc_monitor *m;
1461
1462         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1463         if (!m) {
1464             return jsonrpc_create_error(json_string_create("unknown monitor"),
1465                                         request_id);
1466         } else {
1467             ovsdb_jsonrpc_monitor_destroy(m);
1468             return jsonrpc_create_reply(json_object_create(), request_id);
1469         }
1470     }
1471 }
1472
1473 static void
1474 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1475 {
1476     struct ovsdb_jsonrpc_monitor *m, *next;
1477
1478     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1479         ovsdb_jsonrpc_monitor_destroy(m);
1480     }
1481 }
1482
1483 static struct json *
1484 ovsdb_jsonrpc_monitor_compose_update(struct ovsdb_jsonrpc_monitor *m,
1485                                      bool initial)
1486 {
1487
1488     if (!ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
1489         return NULL;
1490     }
1491
1492     return ovsdb_monitor_get_update(m->dbmon, initial, false,
1493                                     &m->unflushed, m->condition, m->version);
1494 }
1495
1496 static bool
1497 ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *s)
1498 {
1499     struct ovsdb_jsonrpc_monitor *m;
1500
1501     HMAP_FOR_EACH (m, node, &s->monitors) {
1502         if (ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
1503             return true;
1504         }
1505     }
1506
1507     return false;
1508 }
1509
1510 void
1511 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_jsonrpc_monitor *m)
1512 {
1513     json_destroy(m->monitor_id);
1514     hmap_remove(&m->session->monitors, &m->node);
1515     ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m, m->unflushed);
1516     ovsdb_monitor_session_condition_destroy(m->condition);
1517     free(m);
1518 }
1519
1520 static struct jsonrpc_msg *
1521 ovsdb_jsonrpc_create_notify(const struct ovsdb_jsonrpc_monitor *m,
1522                             struct json *params)
1523 {
1524     const char *method;
1525
1526     switch(m->version) {
1527     case OVSDB_MONITOR_V1:
1528         method = "update";
1529         break;
1530     case OVSDB_MONITOR_V2:
1531         method = "update2";
1532         break;
1533     case OVSDB_MONITOR_VERSION_MAX:
1534     default:
1535         OVS_NOT_REACHED();
1536     }
1537
1538     return jsonrpc_create_notify(method, params);
1539 }
1540
1541 static void
1542 ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *s)
1543 {
1544     struct ovsdb_jsonrpc_monitor *m;
1545
1546     HMAP_FOR_EACH (m, node, &s->monitors) {
1547         struct json *json;
1548
1549         json = ovsdb_jsonrpc_monitor_compose_update(m, false);
1550         if (json) {
1551             struct jsonrpc_msg *msg;
1552             struct json *params;
1553
1554             params = json_array_create_2(json_clone(m->monitor_id), json);
1555             msg = ovsdb_jsonrpc_create_notify(m, params);
1556             jsonrpc_session_send(s->js, msg);
1557         }
1558     }
1559 }
1560
1561 void
1562 ovsdb_jsonrpc_disable_monitor2(void)
1563 {
1564     /* Once disabled, it is not possible to re-enable it. */
1565     monitor2_enable__ = false;
1566 }