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