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 "openvswitch/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 "util.h"
  43 #include "openvswitch/vlog.h"
  44
  45 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
  46
  47 struct ovsdb_jsonrpc_remote;
  48 struct ovsdb_jsonrpc_session;
  49
  50 /* Set false to defeature monitor_cond, causing jsonrpc to respond to
  51  * monitor_cond method with an error.  */
  52 static bool monitor_cond_enable__ = true;
  53
  54 /* Message rate-limiting. */
  55 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  56
  57 /* Sessions. */
  58 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  59     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  60 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  61 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  62 static void ovsdb_jsonrpc_session_get_memory_usage_all(
  63     const struct ovsdb_jsonrpc_remote *, struct simap *usage);
  64 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  65 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  66 static void ovsdb_jsonrpc_session_set_all_options(
  67     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  68 static bool ovsdb_jsonrpc_active_session_get_status(
  69     const struct ovsdb_jsonrpc_remote *,
  70     struct ovsdb_jsonrpc_remote_status *);
  71 static void ovsdb_jsonrpc_session_get_status(
  72     const struct ovsdb_jsonrpc_session *,
  73     struct ovsdb_jsonrpc_remote_status *);
  74 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  75 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  76 static void ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *,
  77                                        struct jsonrpc_msg *);
  78
  79 /* Triggers. */
  80 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  81                                          struct ovsdb *,
  82                                          struct json *id, struct json *params);
  83 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  84     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  85 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  86 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  87 static void ovsdb_jsonrpc_trigger_complete_done(
  88     struct ovsdb_jsonrpc_session *);
  89
  90 /* Monitors. */
  91 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_create(
  92     struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params,
  93     enum ovsdb_monitor_version, const struct json *request_id);
  94 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cond_change(
  95     struct ovsdb_jsonrpc_session *s,
  96     struct json *params,
  97     const struct json *request_id);
  98 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  99     struct ovsdb_jsonrpc_session *,
 100     struct json_array *params,
 101     const struct json *request_id);
 102 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
 103 static void ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *);
 104 static bool ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *);
 105 static struct json *ovsdb_jsonrpc_monitor_compose_update(
 106     struct ovsdb_jsonrpc_monitor *monitor, bool initial);
 107 static struct jsonrpc_msg * ovsdb_jsonrpc_create_notify(
 108                                         const struct ovsdb_jsonrpc_monitor *m,
 109                                         struct json *params);
 110
 111 \f
 112 /* JSON-RPC database server. */
 113
 114 struct ovsdb_jsonrpc_server {
 115     struct ovsdb_server up;
 116     unsigned int n_sessions;
 117     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
 118 };
 119
 120 /* A configured remote.  This is either a passive stream listener plus a list
 121  * of the currently connected sessions, or a list of exactly one active
 122  * session. */
 123 struct ovsdb_jsonrpc_remote {
 124     struct ovsdb_jsonrpc_server *server;
 125     struct pstream *listener;   /* Listener, if passive. */
 126     struct ovs_list sessions;   /* List of "struct ovsdb_jsonrpc_session"s. */
 127     uint8_t dscp;
 128 };
 129
 130 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 131     struct ovsdb_jsonrpc_server *, const char *name,
 132     const struct ovsdb_jsonrpc_options *options
 133 );
 134 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 135
 136 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 137  *
 138  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 139  * which 'server' should provide access. */
 140 struct ovsdb_jsonrpc_server *
 141 ovsdb_jsonrpc_server_create(void)
 142 {
 143     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 144     ovsdb_server_init(&server->up);
 145     shash_init(&server->remotes);
 146     return server;
 147 }
 148
 149 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 150  * successful, false if 'db''s name is the same as some database already in
 151  * 'server'. */
 152 bool
 153 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 154 {
 155     /* The OVSDB protocol doesn't have a way to notify a client that a
 156      * database has been added.  If some client tried to use the database
 157      * that we're adding and failed, then forcing it to reconnect seems like
 158      * a reasonable way to make it try again.
 159      *
 160      * If this is too big of a hammer in practice, we could be more selective,
 161      * e.g. disconnect only connections that actually tried to use a database
 162      * with 'db''s name. */
 163     ovsdb_jsonrpc_server_reconnect(svr);
 164
 165     return ovsdb_server_add_db(&svr->up, db);
 166 }
 167
 168 /* Removes 'db' from the set of databases served out by 'svr'.  Returns
 169  * true if successful, false if there is no database associated with 'db'. */
 170 bool
 171 ovsdb_jsonrpc_server_remove_db(struct ovsdb_jsonrpc_server *svr,
 172                                struct ovsdb *db)
 173 {
 174     /* There might be pointers to 'db' from 'svr', such as monitors or
 175      * outstanding transactions.  Disconnect all JSON-RPC connections to avoid
 176      * accesses to freed memory.
 177      *
 178      * If this is too big of a hammer in practice, we could be more selective,
 179      * e.g. disconnect only connections that actually reference 'db'. */
 180     ovsdb_jsonrpc_server_reconnect(svr);
 181
 182     return ovsdb_server_remove_db(&svr->up, db);
 183 }
 184
 185 void
 186 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 187 {
 188     struct shash_node *node, *next;
 189
 190     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 191         ovsdb_jsonrpc_server_del_remote(node);
 192     }
 193     shash_destroy(&svr->remotes);
 194     ovsdb_server_destroy(&svr->up);
 195     free(svr);
 196 }
 197
 198 struct ovsdb_jsonrpc_options *
 199 ovsdb_jsonrpc_default_options(const char *target)
 200 {
 201     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 202     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 203     options->probe_interval = (stream_or_pstream_needs_probes(target)
 204                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 205                                : 0);
 206     return options;
 207 }
 208
 209 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 210  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 211  *
 212  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 213  * "tcp:1.2.3.4". */
 214 void
 215 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 216                                  const struct shash *new_remotes)
 217 {
 218     struct shash_node *node, *next;
 219
 220     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 221         struct ovsdb_jsonrpc_remote *remote = node->data;
 222         struct ovsdb_jsonrpc_options *options
 223             = shash_find_data(new_remotes, node->name);
 224
 225         if (!options) {
 226             VLOG_INFO("%s: remote deconfigured", node->name);
 227             ovsdb_jsonrpc_server_del_remote(node);
 228         } else if (options->dscp != remote->dscp) {
 229             ovsdb_jsonrpc_server_del_remote(node);
 230          }
 231     }
 232     SHASH_FOR_EACH (node, new_remotes) {
 233         const struct ovsdb_jsonrpc_options *options = node->data;
 234         struct ovsdb_jsonrpc_remote *remote;
 235
 236         remote = shash_find_data(&svr->remotes, node->name);
 237         if (!remote) {
 238             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 239             if (!remote) {
 240                 continue;
 241             }
 242         }
 243
 244         ovsdb_jsonrpc_session_set_all_options(remote, options);
 245     }
 246 }
 247
 248 static struct ovsdb_jsonrpc_remote *
 249 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 250                                 const char *name,
 251                                 const struct ovsdb_jsonrpc_options *options)
 252 {
 253     struct ovsdb_jsonrpc_remote *remote;
 254     struct pstream *listener;
 255     int error;
 256
 257     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 258     if (error && error != EAFNOSUPPORT) {
 259         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, ovs_strerror(error));
 260         return NULL;
 261     }
 262
 263     remote = xmalloc(sizeof *remote);
 264     remote->server = svr;
 265     remote->listener = listener;
 266     ovs_list_init(&remote->sessions);
 267     remote->dscp = options->dscp;
 268     shash_add(&svr->remotes, name, remote);
 269
 270     if (!listener) {
 271         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true));
 272     }
 273     return remote;
 274 }
 275
 276 static void
 277 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 278 {
 279     struct ovsdb_jsonrpc_remote *remote = node->data;
 280
 281     ovsdb_jsonrpc_session_close_all(remote);
 282     pstream_close(remote->listener);
 283     shash_delete(&remote->server->remotes, node);
 284     free(remote);
 285 }
 286
 287 /* Stores status information for the remote named 'target', which should have
 288  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 289  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 290  * a remote named 'target' or if that remote is an outbound remote that has no
 291  * active connections) returns false.  On failure, 'status' will be zeroed.
 292  */
 293 bool
 294 ovsdb_jsonrpc_server_get_remote_status(
 295     const struct ovsdb_jsonrpc_server *svr, const char *target,
 296     struct ovsdb_jsonrpc_remote_status *status)
 297 {
 298     const struct ovsdb_jsonrpc_remote *remote;
 299
 300     memset(status, 0, sizeof *status);
 301
 302     remote = shash_find_data(&svr->remotes, target);
 303
 304     if (!remote) {
 305         return false;
 306     }
 307
 308     if (remote->listener) {
 309         status->bound_port = pstream_get_bound_port(remote->listener);
 310         status->is_connected = !ovs_list_is_empty(&remote->sessions);
 311         status->n_connections = ovs_list_size(&remote->sessions);
 312         return true;
 313     }
 314
 315     return ovsdb_jsonrpc_active_session_get_status(remote, status);
 316 }
 317
 318 void
 319 ovsdb_jsonrpc_server_free_remote_status(
 320     struct ovsdb_jsonrpc_remote_status *status)
 321 {
 322     free(status->locks_held);
 323     free(status->locks_waiting);
 324     free(status->locks_lost);
 325 }
 326
 327 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 328  * reconnect. */
 329 void
 330 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 331 {
 332     struct shash_node *node;
 333
 334     SHASH_FOR_EACH (node, &svr->remotes) {
 335         struct ovsdb_jsonrpc_remote *remote = node->data;
 336
 337         ovsdb_jsonrpc_session_reconnect_all(remote);
 338     }
 339 }
 340
 341 void
 342 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 343 {
 344     struct shash_node *node;
 345
 346     SHASH_FOR_EACH (node, &svr->remotes) {
 347         struct ovsdb_jsonrpc_remote *remote = node->data;
 348
 349         if (remote->listener) {
 350             struct stream *stream;
 351             int error;
 352
 353             error = pstream_accept(remote->listener, &stream);
 354             if (!error) {
 355                 struct jsonrpc_session *js;
 356                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
 357                                                      remote->dscp);
 358                 ovsdb_jsonrpc_session_create(remote, js);
 359             } else if (error != EAGAIN) {
 360                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 361                              pstream_get_name(remote->listener),
 362                              ovs_strerror(error));
 363             }
 364         }
 365
 366         ovsdb_jsonrpc_session_run_all(remote);
 367     }
 368 }
 369
 370 void
 371 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 372 {
 373     struct shash_node *node;
 374
 375     SHASH_FOR_EACH (node, &svr->remotes) {
 376         struct ovsdb_jsonrpc_remote *remote = node->data;
 377
 378         if (remote->listener) {
 379             pstream_wait(remote->listener);
 380         }
 381
 382         ovsdb_jsonrpc_session_wait_all(remote);
 383     }
 384 }
 385
 386 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 387  * memory_report(). */
 388 void
 389 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 390                                       struct simap *usage)
 391 {
 392     struct shash_node *node;
 393
 394     simap_increase(usage, "sessions", svr->n_sessions);
 395     SHASH_FOR_EACH (node, &svr->remotes) {
 396         struct ovsdb_jsonrpc_remote *remote = node->data;
 397
 398         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 399     }
 400 }
 401 \f
 402 /* JSON-RPC database server session. */
 403
 404 struct ovsdb_jsonrpc_session {
 405     struct ovs_list node;       /* Element in remote's sessions list. */
 406     struct ovsdb_session up;
 407     struct ovsdb_jsonrpc_remote *remote;
 408
 409     /* Triggers. */
 410     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 411
 412     /* Monitors. */
 413     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 414
 415     /* Network connectivity. */
 416     struct jsonrpc_session *js;  /* JSON-RPC session. */
 417     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 418 };
 419
 420 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 421 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 422 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 423 static void ovsdb_jsonrpc_session_get_memory_usage(
 424     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 425 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 426                                               struct jsonrpc_msg *);
 427 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 428                                              struct jsonrpc_msg *);
 429
 430 static struct ovsdb_jsonrpc_session *
 431 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 432                              struct jsonrpc_session *js)
 433 {
 434     struct ovsdb_jsonrpc_session *s;
 435
 436     s = xzalloc(sizeof *s);
 437     ovsdb_session_init(&s->up, &remote->server->up);
 438     s->remote = remote;
 439     ovs_list_push_back(&remote->sessions, &s->node);
 440     hmap_init(&s->triggers);
 441     hmap_init(&s->monitors);
 442     s->js = js;
 443     s->js_seqno = jsonrpc_session_get_seqno(js);
 444
 445     remote->server->n_sessions++;
 446
 447     return s;
 448 }
 449
 450 static void
 451 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 452 {
 453     ovsdb_jsonrpc_monitor_remove_all(s);
 454     ovsdb_jsonrpc_session_unlock_all(s);
 455     ovsdb_jsonrpc_trigger_complete_all(s);
 456
 457     hmap_destroy(&s->monitors);
 458     hmap_destroy(&s->triggers);
 459
 460     jsonrpc_session_close(s->js);
 461     ovs_list_remove(&s->node);
 462     s->remote->server->n_sessions--;
 463     ovsdb_session_destroy(&s->up);
 464     free(s);
 465 }
 466
 467 static int
 468 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 469 {
 470     jsonrpc_session_run(s->js);
 471     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 472         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 473         ovsdb_jsonrpc_trigger_complete_all(s);
 474         ovsdb_jsonrpc_monitor_remove_all(s);
 475         ovsdb_jsonrpc_session_unlock_all(s);
 476     }
 477
 478     ovsdb_jsonrpc_trigger_complete_done(s);
 479
 480     if (!jsonrpc_session_get_backlog(s->js)) {
 481         struct jsonrpc_msg *msg;
 482
 483         ovsdb_jsonrpc_monitor_flush_all(s);
 484
 485         msg = jsonrpc_session_recv(s->js);
 486         if (msg) {
 487             if (msg->type == JSONRPC_REQUEST) {
 488                 ovsdb_jsonrpc_session_got_request(s, msg);
 489             } else if (msg->type == JSONRPC_NOTIFY) {
 490                 ovsdb_jsonrpc_session_got_notify(s, msg);
 491             } else {
 492                 VLOG_WARN("%s: received unexpected %s message",
 493                           jsonrpc_session_get_name(s->js),
 494                           jsonrpc_msg_type_to_string(msg->type));
 495                 jsonrpc_session_force_reconnect(s->js);
 496                 jsonrpc_msg_destroy(msg);
 497             }
 498         }
 499     }
 500     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 501 }
 502
 503 static void
 504 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 505                                   const struct ovsdb_jsonrpc_options *options)
 506 {
 507     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 508     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 509     jsonrpc_session_set_dscp(session->js, options->dscp);
 510 }
 511
 512 static void
 513 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 514 {
 515     struct ovsdb_jsonrpc_session *s, *next;
 516
 517     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 518         int error = ovsdb_jsonrpc_session_run(s);
 519         if (error) {
 520             ovsdb_jsonrpc_session_close(s);
 521         }
 522     }
 523 }
 524
 525 static void
 526 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 527 {
 528     jsonrpc_session_wait(s->js);
 529     if (!jsonrpc_session_get_backlog(s->js)) {
 530         if (ovsdb_jsonrpc_monitor_needs_flush(s)) {
 531             poll_immediate_wake();
 532         } else {
 533             jsonrpc_session_recv_wait(s->js);
 534         }
 535     }
 536 }
 537
 538 static void
 539 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 540 {
 541     struct ovsdb_jsonrpc_session *s;
 542
 543     LIST_FOR_EACH (s, node, &remote->sessions) {
 544         ovsdb_jsonrpc_session_wait(s);
 545     }
 546 }
 547
 548 static void
 549 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 550                                        struct simap *usage)
 551 {
 552     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 553     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 554 }
 555
 556 static void
 557 ovsdb_jsonrpc_session_get_memory_usage_all(
 558     const struct ovsdb_jsonrpc_remote *remote,
 559     struct simap *usage)
 560 {
 561     struct ovsdb_jsonrpc_session *s;
 562
 563     LIST_FOR_EACH (s, node, &remote->sessions) {
 564         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 565     }
 566 }
 567
 568 static void
 569 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 570 {
 571     struct ovsdb_jsonrpc_session *s, *next;
 572
 573     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 574         ovsdb_jsonrpc_session_close(s);
 575     }
 576 }
 577
 578 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 579  * reconnect. */
 580 static void
 581 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 582 {
 583     struct ovsdb_jsonrpc_session *s, *next;
 584
 585     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 586         jsonrpc_session_force_reconnect(s->js);
 587         if (!jsonrpc_session_is_alive(s->js)) {
 588             ovsdb_jsonrpc_session_close(s);
 589         }
 590     }
 591 }
 592
 593 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 594  * 'options'.
 595  *
 596  * (The dscp value can't be changed directly; the caller must instead close and
 597  * re-open the session.) */
 598 static void
 599 ovsdb_jsonrpc_session_set_all_options(
 600     struct ovsdb_jsonrpc_remote *remote,
 601     const struct ovsdb_jsonrpc_options *options)
 602 {
 603     struct ovsdb_jsonrpc_session *s;
 604
 605     LIST_FOR_EACH (s, node, &remote->sessions) {
 606         ovsdb_jsonrpc_session_set_options(s, options);
 607     }
 608 }
 609
 610 /* Sets the 'status' of for the 'remote' with an outgoing connection.   */
 611 static bool
 612 ovsdb_jsonrpc_active_session_get_status(
 613     const struct ovsdb_jsonrpc_remote *remote,
 614     struct ovsdb_jsonrpc_remote_status *status)
 615 {
 616     const struct ovs_list *sessions = &remote->sessions;
 617     const struct ovsdb_jsonrpc_session *s;
 618
 619     if (ovs_list_is_empty(sessions)) {
 620         return false;
 621     }
 622
 623     ovs_assert(ovs_list_is_singleton(sessions));
 624     s = CONTAINER_OF(ovs_list_front(sessions), struct ovsdb_jsonrpc_session, node);
 625     ovsdb_jsonrpc_session_get_status(s, status);
 626     status->n_connections = 1;
 627
 628     return true;
 629 }
 630
 631 static void
 632 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_session *session,
 633                                  struct ovsdb_jsonrpc_remote_status *status)
 634 {
 635     const struct ovsdb_jsonrpc_session *s = session;
 636     const struct jsonrpc_session *js;
 637     struct ovsdb_lock_waiter *waiter;
 638     struct reconnect_stats rstats;
 639     struct ds locks_held, locks_waiting, locks_lost;
 640
 641     js = s->js;
 642
 643     status->is_connected = jsonrpc_session_is_connected(js);
 644     status->last_error = jsonrpc_session_get_status(js);
 645
 646     jsonrpc_session_get_reconnect_stats(js, &rstats);
 647     status->state = rstats.state;
 648     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 649         ? UINT_MAX : rstats.msec_since_connect / 1000;
 650     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 651         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 652
 653     ds_init(&locks_held);
 654     ds_init(&locks_waiting);
 655     ds_init(&locks_lost);
 656     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 657         struct ds *string;
 658
 659         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 660                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 661                   : &locks_lost);
 662         if (string->length) {
 663             ds_put_char(string, ' ');
 664         }
 665         ds_put_cstr(string, waiter->lock_name);
 666     }
 667     status->locks_held = ds_steal_cstr(&locks_held);
 668     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 669     status->locks_lost = ds_steal_cstr(&locks_lost);
 670 }
 671
 672 /* Examines 'request' to determine the database to which it relates, and then
 673  * searches 's' to find that database:
 674  *
 675  *    - If successful, returns the database and sets '*replyp' to NULL.
 676  *
 677  *    - If no such database exists, returns NULL and sets '*replyp' to an
 678  *      appropriate JSON-RPC error reply, owned by the caller. */
 679 static struct ovsdb *
 680 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 681                         const struct jsonrpc_msg *request,
 682                         struct jsonrpc_msg **replyp)
 683 {
 684     struct json_array *params;
 685     struct ovsdb_error *error;
 686     const char *db_name;
 687     struct ovsdb *db;
 688
 689     params = json_array(request->params);
 690     if (!params->n || params->elems[0]->type != JSON_STRING) {
 691         error = ovsdb_syntax_error(
 692             request->params, NULL,
 693             "%s request params must begin with <db-name>", request->method);
 694         goto error;
 695     }
 696
 697     db_name = params->elems[0]->u.string;
 698     db = shash_find_data(&s->up.server->dbs, db_name);
 699     if (!db) {
 700         error = ovsdb_syntax_error(
 701             request->params, "unknown database",
 702             "%s request specifies unknown database %s",
 703             request->method, db_name);
 704         goto error;
 705     }
 706
 707     *replyp = NULL;
 708     return db;
 709
 710 error:
 711     *replyp = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 712     ovsdb_error_destroy(error);
 713     return NULL;
 714 }
 715
 716 static struct ovsdb_error *
 717 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 718                                       const char **lock_namep)
 719 {
 720     const struct json_array *params;
 721
 722     params = json_array(request->params);
 723     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 724         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 725         *lock_namep = NULL;
 726         return ovsdb_syntax_error(request->params, NULL,
 727                                   "%s request params must be <id>",
 728                                   request->method);
 729     }
 730
 731     *lock_namep = json_string(params->elems[0]);
 732     return NULL;
 733 }
 734
 735 static void
 736 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 737                              const char *lock_name,
 738                              const char *method)
 739 {
 740     struct ovsdb_jsonrpc_session *s;
 741     struct json *params;
 742
 743     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 744     params = json_array_create_1(json_string_create(lock_name));
 745     ovsdb_jsonrpc_session_send(s, jsonrpc_create_notify(method, params));
 746 }
 747
 748 static struct jsonrpc_msg *
 749 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 750                            struct jsonrpc_msg *request,
 751                            enum ovsdb_lock_mode mode)
 752 {
 753     struct ovsdb_lock_waiter *waiter;
 754     struct jsonrpc_msg *reply;
 755     struct ovsdb_error *error;
 756     struct ovsdb_session *victim;
 757     const char *lock_name;
 758     struct json *result;
 759
 760     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 761     if (error) {
 762         goto error;
 763     }
 764
 765     /* Report error if this session has issued a "lock" or "steal" without a
 766      * matching "unlock" for this lock. */
 767     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 768     if (waiter) {
 769         error = ovsdb_syntax_error(
 770             request->params, NULL,
 771             "must issue \"unlock\" before new \"%s\"", request->method);
 772         goto error;
 773     }
 774
 775     /* Get the lock, add us as a waiter. */
 776     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 777                                &victim);
 778     if (victim) {
 779         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 780     }
 781
 782     result = json_object_create();
 783     json_object_put(result, "locked",
 784                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 785
 786     return jsonrpc_create_reply(result, request->id);
 787
 788 error:
 789     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 790     ovsdb_error_destroy(error);
 791     return reply;
 792 }
 793
 794 static void
 795 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 796 {
 797     struct ovsdb_lock_waiter *waiter, *next;
 798
 799     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 800         ovsdb_jsonrpc_session_unlock__(waiter);
 801     }
 802 }
 803
 804 static void
 805 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 806 {
 807     struct ovsdb_lock *lock = waiter->lock;
 808
 809     if (lock) {
 810         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 811         if (new_owner) {
 812             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 813         } else {
 814             /* ovsdb_server_lock() might have freed 'lock'. */
 815         }
 816     }
 817
 818     ovsdb_lock_waiter_destroy(waiter);
 819 }
 820
 821 static struct jsonrpc_msg *
 822 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 823                              struct jsonrpc_msg *request)
 824 {
 825     struct ovsdb_lock_waiter *waiter;
 826     struct jsonrpc_msg *reply;
 827     struct ovsdb_error *error;
 828     const char *lock_name;
 829
 830     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 831     if (error) {
 832         goto error;
 833     }
 834
 835     /* Report error if this session has not issued a "lock" or "steal" for this
 836      * lock. */
 837     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 838     if (!waiter) {
 839         error = ovsdb_syntax_error(
 840             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 841         goto error;
 842     }
 843
 844     ovsdb_jsonrpc_session_unlock__(waiter);
 845
 846     return jsonrpc_create_reply(json_object_create(), request->id);
 847
 848 error:
 849     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 850     ovsdb_error_destroy(error);
 851     return reply;
 852 }
 853
 854 static struct jsonrpc_msg *
 855 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 856                     struct jsonrpc_msg *request)
 857 {
 858     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 859     request->id = NULL;
 860     request->params = NULL;
 861     jsonrpc_msg_destroy(request);
 862     return NULL;
 863 }
 864
 865 static void
 866 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 867                                   struct jsonrpc_msg *request)
 868 {
 869     struct jsonrpc_msg *reply;
 870
 871     if (!strcmp(request->method, "transact")) {
 872         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 873         if (!reply) {
 874             reply = execute_transaction(s, db, request);
 875         }
 876     } else if (!strcmp(request->method, "monitor") ||
 877                (monitor_cond_enable__ && !strcmp(request->method,
 878                                                  "monitor_cond"))) {
 879         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 880         if (!reply) {
 881             int l = strlen(request->method) - strlen("monitor");
 882             enum ovsdb_monitor_version version = l ? OVSDB_MONITOR_V2
 883                                                    : OVSDB_MONITOR_V1;
 884             reply = ovsdb_jsonrpc_monitor_create(s, db, request->params,
 885                                                  version, request->id);
 886         }
 887     } else if (!strcmp(request->method, "monitor_cond_change")) {
 888         reply = ovsdb_jsonrpc_monitor_cond_change(s, request->params,
 889                                                   request->id);
 890     } else if (!strcmp(request->method, "monitor_cancel")) {
 891         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 892                                              request->id);
 893     } else if (!strcmp(request->method, "get_schema")) {
 894         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 895         if (!reply) {
 896             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 897                                          request->id);
 898         }
 899     } else if (!strcmp(request->method, "list_dbs")) {
 900         size_t n_dbs = shash_count(&s->up.server->dbs);
 901         struct shash_node *node;
 902         struct json **dbs;
 903         size_t i;
 904
 905         dbs = xmalloc(n_dbs * sizeof *dbs);
 906         i = 0;
 907         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 908             dbs[i++] = json_string_create(node->name);
 909         }
 910         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 911                                      request->id);
 912     } else if (!strcmp(request->method, "lock")) {
 913         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 914     } else if (!strcmp(request->method, "steal")) {
 915         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 916     } else if (!strcmp(request->method, "unlock")) {
 917         reply = ovsdb_jsonrpc_session_unlock(s, request);
 918     } else if (!strcmp(request->method, "echo")) {
 919         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 920     } else {
 921         reply = jsonrpc_create_error(json_string_create("unknown method"),
 922                                      request->id);
 923     }
 924
 925     if (reply) {
 926         jsonrpc_msg_destroy(request);
 927         ovsdb_jsonrpc_session_send(s, reply);
 928     }
 929 }
 930
 931 static void
 932 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 933 {
 934     if (json_array(request->params)->n == 1) {
 935         struct ovsdb_jsonrpc_trigger *t;
 936         struct json *id;
 937
 938         id = request->params->u.array.elems[0];
 939         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 940         if (t) {
 941             ovsdb_jsonrpc_trigger_complete(t);
 942         }
 943     }
 944 }
 945
 946 static void
 947 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 948                                  struct jsonrpc_msg *request)
 949 {
 950     if (!strcmp(request->method, "cancel")) {
 951         execute_cancel(s, request);
 952     }
 953     jsonrpc_msg_destroy(request);
 954 }
 955
 956 static void
 957 ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *s,
 958                            struct jsonrpc_msg *msg)
 959 {
 960     ovsdb_jsonrpc_monitor_flush_all(s);
 961     jsonrpc_session_send(s->js, msg);
 962 }
 963 \f
 964 /* JSON-RPC database server triggers.
 965  *
 966  * (Every transaction is treated as a trigger even if it doesn't actually have
 967  * any "wait" operations.) */
 968
 969 struct ovsdb_jsonrpc_trigger {
 970     struct ovsdb_trigger trigger;
 971     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 972     struct json *id;
 973 };
 974
 975 static void
 976 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 977                              struct json *id, struct json *params)
 978 {
 979     struct ovsdb_jsonrpc_trigger *t;
 980     size_t hash;
 981
 982     /* Check for duplicate ID. */
 983     hash = json_hash(id, 0);
 984     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 985     if (t) {
 986         struct jsonrpc_msg *msg;
 987
 988         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 989                                    id);
 990         ovsdb_jsonrpc_session_send(s, msg);
 991         json_destroy(id);
 992         json_destroy(params);
 993         return;
 994     }
 995
 996     /* Insert into trigger table. */
 997     t = xmalloc(sizeof *t);
 998     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 999     t->id = id;
1000     hmap_insert(&s->triggers, &t->hmap_node, hash);
1001
1002     /* Complete early if possible. */
1003     if (ovsdb_trigger_is_complete(&t->trigger)) {
1004         ovsdb_jsonrpc_trigger_complete(t);
1005     }
1006 }
1007
1008 static struct ovsdb_jsonrpc_trigger *
1009 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
1010                            const struct json *id, size_t hash)
1011 {
1012     struct ovsdb_jsonrpc_trigger *t;
1013
1014     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
1015         if (json_equal(t->id, id)) {
1016             return t;
1017         }
1018     }
1019
1020     return NULL;
1021 }
1022
1023 static void
1024 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
1025 {
1026     struct ovsdb_jsonrpc_session *s;
1027
1028     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
1029
1030     if (jsonrpc_session_is_connected(s->js)) {
1031         struct jsonrpc_msg *reply;
1032         struct json *result;
1033
1034         result = ovsdb_trigger_steal_result(&t->trigger);
1035         if (result) {
1036             reply = jsonrpc_create_reply(result, t->id);
1037         } else {
1038             reply = jsonrpc_create_error(json_string_create("canceled"),
1039                                          t->id);
1040         }
1041         ovsdb_jsonrpc_session_send(s, reply);
1042     }
1043
1044     json_destroy(t->id);
1045     ovsdb_trigger_destroy(&t->trigger);
1046     hmap_remove(&s->triggers, &t->hmap_node);
1047     free(t);
1048 }
1049
1050 static void
1051 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
1052 {
1053     struct ovsdb_jsonrpc_trigger *t, *next;
1054     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
1055         ovsdb_jsonrpc_trigger_complete(t);
1056     }
1057 }
1058
1059 static void
1060 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
1061 {
1062     while (!ovs_list_is_empty(&s->up.completions)) {
1063         struct ovsdb_jsonrpc_trigger *t
1064             = CONTAINER_OF(s->up.completions.next,
1065                            struct ovsdb_jsonrpc_trigger, trigger.node);
1066         ovsdb_jsonrpc_trigger_complete(t);
1067     }
1068 }
1069 \f
1070 /* Jsonrpc front end monitor. */
1071 struct ovsdb_jsonrpc_monitor {
1072     struct ovsdb_jsonrpc_session *session;
1073     struct ovsdb *db;
1074     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1075     struct json *monitor_id;
1076     struct ovsdb_monitor *dbmon;
1077     uint64_t unflushed;         /* The first transaction that has not been
1078                                        flushed to the jsonrpc remote client. */
1079     enum ovsdb_monitor_version version;
1080     struct ovsdb_monitor_session_condition *condition;/* Session's condition */
1081 };
1082
1083 static struct ovsdb_jsonrpc_monitor *
1084 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1085                            const struct json *monitor_id)
1086 {
1087     struct ovsdb_jsonrpc_monitor *m;
1088
1089     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1090         if (json_equal(m->monitor_id, monitor_id)) {
1091             return m;
1092         }
1093     }
1094
1095     return NULL;
1096 }
1097
1098 static bool
1099 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1100 {
1101     const struct json *json;
1102
1103     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1104     return json ? json_boolean(json) : default_value;
1105 }
1106
1107 static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
1108 ovsdb_jsonrpc_parse_monitor_request(
1109                                struct ovsdb_monitor *dbmon,
1110                                const struct ovsdb_table *table,
1111                                struct ovsdb_monitor_session_condition *cond,
1112                                const struct json *monitor_request)
1113 {
1114     const struct ovsdb_table_schema *ts = table->schema;
1115     enum ovsdb_monitor_selection select;
1116     const struct json *columns, *select_json, *where = NULL;
1117     struct ovsdb_parser parser;
1118     struct ovsdb_error *error;
1119
1120     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1121     if (cond) {
1122         where = ovsdb_parser_member(&parser, "where", OP_ARRAY | OP_OPTIONAL);
1123     }
1124     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1125
1126     select_json = ovsdb_parser_member(&parser, "select",
1127                                       OP_OBJECT | OP_OPTIONAL);
1128
1129     error = ovsdb_parser_finish(&parser);
1130     if (error) {
1131         return error;
1132     }
1133
1134     if (select_json) {
1135         select = 0;
1136         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1137         if (parse_bool(&parser, "initial", true)) {
1138             select |= OJMS_INITIAL;
1139         }
1140         if (parse_bool(&parser, "insert", true)) {
1141             select |= OJMS_INSERT;
1142         }
1143         if (parse_bool(&parser, "delete", true)) {
1144             select |= OJMS_DELETE;
1145         }
1146         if (parse_bool(&parser, "modify", true)) {
1147             select |= OJMS_MODIFY;
1148         }
1149         error = ovsdb_parser_finish(&parser);
1150         if (error) {
1151             return error;
1152         }
1153     } else {
1154         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1155     }
1156
1157     ovsdb_monitor_table_add_select(dbmon, table, select);
1158     if (columns) {
1159         size_t i;
1160
1161         if (columns->type != JSON_ARRAY) {
1162             return ovsdb_syntax_error(columns, NULL,
1163                                       "array of column names expected");
1164         }
1165
1166         for (i = 0; i < columns->u.array.n; i++) {
1167             const struct ovsdb_column *column;
1168             const char *s;
1169
1170             if (columns->u.array.elems[i]->type != JSON_STRING) {
1171                 return ovsdb_syntax_error(columns, NULL,
1172                                           "array of column names expected");
1173             }
1174
1175             s = columns->u.array.elems[i]->u.string;
1176             column = shash_find_data(&table->schema->columns, s);
1177             if (!column) {
1178                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1179                                           "column name", s);
1180             }
1181             if (ovsdb_monitor_add_column(dbmon, table, column,
1182                                          select, true)) {
1183                 return ovsdb_syntax_error(columns, NULL, "column %s "
1184                                           "mentioned more than once",
1185                                           column->name);
1186             }
1187         }
1188     } else {
1189         struct shash_node *node;
1190
1191         SHASH_FOR_EACH (node, &ts->columns) {
1192             const struct ovsdb_column *column = node->data;
1193             if (column->index != OVSDB_COL_UUID) {
1194                 if (ovsdb_monitor_add_column(dbmon, table, column,
1195                                              select, true)) {
1196                     return ovsdb_syntax_error(columns, NULL, "column %s "
1197                                               "mentioned more than once",
1198                                               column->name);
1199                 }
1200             }
1201         }
1202     }
1203     if (cond) {
1204         error = ovsdb_monitor_table_condition_create(cond, table, where);
1205         if (error) {
1206             return error;
1207         }
1208     }
1209
1210     return NULL;
1211 }
1212
1213 static struct jsonrpc_msg *
1214 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1215                              struct json *params,
1216                              enum ovsdb_monitor_version version,
1217                              const struct json *request_id)
1218 {
1219     struct ovsdb_jsonrpc_monitor *m = NULL;
1220     struct ovsdb_monitor *dbmon = NULL;
1221     struct json *monitor_id, *monitor_requests;
1222     struct ovsdb_error *error = NULL;
1223     struct shash_node *node;
1224     struct json *json;
1225
1226     if (json_array(params)->n != 3) {
1227         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1228         goto error;
1229     }
1230     monitor_id = params->u.array.elems[1];
1231     monitor_requests = params->u.array.elems[2];
1232     if (monitor_requests->type != JSON_OBJECT) {
1233         error = ovsdb_syntax_error(monitor_requests, NULL,
1234                                    "monitor-requests must be object");
1235         goto error;
1236     }
1237
1238     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1239         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1240         goto error;
1241     }
1242
1243     m = xzalloc(sizeof *m);
1244     m->session = s;
1245     m->db = db;
1246     m->dbmon = ovsdb_monitor_create(db, m);
1247     if (version == OVSDB_MONITOR_V2) {
1248         m->condition = ovsdb_monitor_session_condition_create();
1249     }
1250     m->unflushed = 0;
1251     m->version = version;
1252     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1253     m->monitor_id = json_clone(monitor_id);
1254
1255     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1256         const struct ovsdb_table *table;
1257         const struct json *mr_value;
1258         size_t i;
1259
1260         table = ovsdb_get_table(m->db, node->name);
1261         if (!table) {
1262             error = ovsdb_syntax_error(NULL, NULL,
1263                                        "no table named %s", node->name);
1264             goto error;
1265         }
1266
1267         ovsdb_monitor_add_table(m->dbmon, table);
1268
1269         /* Parse columns. */
1270         mr_value = node->data;
1271         if (mr_value->type == JSON_ARRAY) {
1272             const struct json_array *array = &mr_value->u.array;
1273
1274             for (i = 0; i < array->n; i++) {
1275                 error = ovsdb_jsonrpc_parse_monitor_request(m->dbmon,
1276                                                             table,
1277                                                             m->condition,
1278                                                             array->elems[i]);
1279                 if (error) {
1280                     goto error;
1281                 }
1282             }
1283         } else {
1284             error = ovsdb_jsonrpc_parse_monitor_request(m->dbmon,
1285                                                         table,
1286                                                         m->condition,
1287                                                         mr_value);
1288             if (error) {
1289                 goto error;
1290             }
1291         }
1292     }
1293
1294     dbmon = ovsdb_monitor_add(m->dbmon);
1295     if (dbmon != m->dbmon) {
1296         /* Found an exisiting dbmon, reuse the current one. */
1297         ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m, m->unflushed);
1298         ovsdb_monitor_add_jsonrpc_monitor(dbmon, m);
1299         m->dbmon = dbmon;
1300     }
1301
1302     /* Only now we can bind session's condition to ovsdb_monitor */
1303     if (m->condition) {
1304         ovsdb_monitor_condition_bind(m->dbmon, m->condition);
1305     }
1306
1307     ovsdb_monitor_get_initial(m->dbmon);
1308     json = ovsdb_jsonrpc_monitor_compose_update(m, true);
1309     json = json ? json : json_object_create();
1310     return jsonrpc_create_reply(json, request_id);
1311
1312 error:
1313     if (m) {
1314         ovsdb_jsonrpc_monitor_destroy(m);
1315     }
1316
1317     json = ovsdb_error_to_json(error);
1318     ovsdb_error_destroy(error);
1319     return jsonrpc_create_error(json, request_id);
1320 }
1321
1322 static struct ovsdb_error *
1323 ovsdb_jsonrpc_parse_monitor_cond_change_request(
1324                                 struct ovsdb_jsonrpc_monitor *m,
1325                                 const struct ovsdb_table *table,
1326                                 const struct json *cond_change_req)
1327 {
1328     const struct ovsdb_table_schema *ts = table->schema;
1329     const struct json *condition, *columns;
1330     struct ovsdb_parser parser;
1331     struct ovsdb_error *error;
1332
1333     ovsdb_parser_init(&parser, cond_change_req, "table %s", ts->name);
1334     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1335     condition = ovsdb_parser_member(&parser, "where", OP_ARRAY | OP_OPTIONAL);
1336
1337     error = ovsdb_parser_finish(&parser);
1338     if (error) {
1339         return error;
1340     }
1341
1342     if (columns) {
1343         error = ovsdb_syntax_error(cond_change_req, NULL, "changing columns "
1344                                    "is unsupported");
1345         return error;
1346     }
1347     error = ovsdb_monitor_table_condition_update(m->dbmon, m->condition, table,
1348                                                  condition);
1349
1350     return error;
1351 }
1352
1353 static struct jsonrpc_msg *
1354 ovsdb_jsonrpc_monitor_cond_change(struct ovsdb_jsonrpc_session *s,
1355                                   struct json *params,
1356                                   const struct json *request_id)
1357 {
1358     struct ovsdb_error *error;
1359     struct ovsdb_jsonrpc_monitor *m;
1360     struct json *monitor_cond_change_reqs;
1361     struct shash_node *node;
1362     struct json *json;
1363
1364     if (json_array(params)->n != 3) {
1365         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1366         goto error;
1367     }
1368
1369     m = ovsdb_jsonrpc_monitor_find(s, params->u.array.elems[0]);
1370     if (!m) {
1371         error = ovsdb_syntax_error(request_id, NULL,
1372                                    "unknown monitor session");
1373         goto error;
1374     }
1375
1376     monitor_cond_change_reqs = params->u.array.elems[2];
1377     if (monitor_cond_change_reqs->type != JSON_OBJECT) {
1378         error =
1379             ovsdb_syntax_error(NULL, NULL,
1380                                "monitor-cond-change-requests must be object");
1381         goto error;
1382     }
1383
1384     SHASH_FOR_EACH (node, json_object(monitor_cond_change_reqs)) {
1385         const struct ovsdb_table *table;
1386         const struct json *mr_value;
1387         size_t i;
1388
1389         table = ovsdb_get_table(m->db, node->name);
1390         if (!table) {
1391             error = ovsdb_syntax_error(NULL, NULL,
1392                                        "no table named %s", node->name);
1393             goto error;
1394         }
1395         if (!ovsdb_monitor_table_exists(m->dbmon, table)) {
1396             error = ovsdb_syntax_error(NULL, NULL,
1397                                        "no table named %s in monitor session",
1398                                        node->name);
1399             goto error;
1400         }
1401
1402         mr_value = node->data;
1403         if (mr_value->type == JSON_ARRAY) {
1404             const struct json_array *array = &mr_value->u.array;
1405
1406             for (i = 0; i < array->n; i++) {
1407                 error = ovsdb_jsonrpc_parse_monitor_cond_change_request(
1408                                             m, table, array->elems[i]);
1409                 if (error) {
1410                     goto error;
1411                 }
1412             }
1413         } else {
1414             error = ovsdb_syntax_error(
1415                        NULL, NULL,
1416                        "table %s no monitor-cond-change JSON array",
1417                        node->name);
1418             goto error;
1419         }
1420     }
1421
1422     /* Change monitor id */
1423     hmap_remove(&s->monitors, &m->node);
1424     json_destroy(m->monitor_id);
1425     m->monitor_id = json_clone(params->u.array.elems[1]);
1426     hmap_insert(&s->monitors, &m->node, json_hash(m->monitor_id, 0));
1427
1428     /* Send the new update, if any,  represents the difference from the old
1429      * condition and the new one. */
1430     struct json *update_json;
1431
1432     update_json = ovsdb_monitor_get_update(m->dbmon, false, true,
1433                                     &m->unflushed, m->condition, m->version);
1434     if (update_json) {
1435         struct jsonrpc_msg *msg;
1436         struct json *params;
1437
1438         params = json_array_create_2(json_clone(m->monitor_id), update_json);
1439         msg = ovsdb_jsonrpc_create_notify(m, params);
1440         jsonrpc_session_send(s->js, msg);
1441     }
1442
1443     return jsonrpc_create_reply(json_object_create(), request_id);
1444
1445 error:
1446
1447     json = ovsdb_error_to_json(error);
1448     ovsdb_error_destroy(error);
1449     return jsonrpc_create_error(json, request_id);
1450 }
1451
1452 static struct jsonrpc_msg *
1453 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1454                              struct json_array *params,
1455                              const struct json *request_id)
1456 {
1457     if (params->n != 1) {
1458         return jsonrpc_create_error(json_string_create("invalid parameters"),
1459                                     request_id);
1460     } else {
1461         struct ovsdb_jsonrpc_monitor *m;
1462
1463         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1464         if (!m) {
1465             return jsonrpc_create_error(json_string_create("unknown monitor"),
1466                                         request_id);
1467         } else {
1468             ovsdb_jsonrpc_monitor_destroy(m);
1469             return jsonrpc_create_reply(json_object_create(), request_id);
1470         }
1471     }
1472 }
1473
1474 static void
1475 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1476 {
1477     struct ovsdb_jsonrpc_monitor *m, *next;
1478
1479     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1480         ovsdb_jsonrpc_monitor_destroy(m);
1481     }
1482 }
1483
1484 static struct json *
1485 ovsdb_jsonrpc_monitor_compose_update(struct ovsdb_jsonrpc_monitor *m,
1486                                      bool initial)
1487 {
1488
1489     if (!ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
1490         return NULL;
1491     }
1492
1493     return ovsdb_monitor_get_update(m->dbmon, initial, false,
1494                                     &m->unflushed, m->condition, m->version);
1495 }
1496
1497 static bool
1498 ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *s)
1499 {
1500     struct ovsdb_jsonrpc_monitor *m;
1501
1502     HMAP_FOR_EACH (m, node, &s->monitors) {
1503         if (ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
1504             return true;
1505         }
1506     }
1507
1508     return false;
1509 }
1510
1511 void
1512 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_jsonrpc_monitor *m)
1513 {
1514     json_destroy(m->monitor_id);
1515     hmap_remove(&m->session->monitors, &m->node);
1516     ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m, m->unflushed);
1517     ovsdb_monitor_session_condition_destroy(m->condition);
1518     free(m);
1519 }
1520
1521 static struct jsonrpc_msg *
1522 ovsdb_jsonrpc_create_notify(const struct ovsdb_jsonrpc_monitor *m,
1523                             struct json *params)
1524 {
1525     const char *method;
1526
1527     switch(m->version) {
1528     case OVSDB_MONITOR_V1:
1529         method = "update";
1530         break;
1531     case OVSDB_MONITOR_V2:
1532         method = "update2";
1533         break;
1534     case OVSDB_MONITOR_VERSION_MAX:
1535     default:
1536         OVS_NOT_REACHED();
1537     }
1538
1539     return jsonrpc_create_notify(method, params);
1540 }
1541
1542 static void
1543 ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *s)
1544 {
1545     struct ovsdb_jsonrpc_monitor *m;
1546
1547     HMAP_FOR_EACH (m, node, &s->monitors) {
1548         struct json *json;
1549
1550         json = ovsdb_jsonrpc_monitor_compose_update(m, false);
1551         if (json) {
1552             struct jsonrpc_msg *msg;
1553             struct json *params;
1554
1555             params = json_array_create_2(json_clone(m->monitor_id), json);
1556             msg = ovsdb_jsonrpc_create_notify(m, params);
1557             jsonrpc_session_send(s->js, msg);
1558         }
1559     }
1560 }
1561
1562 void
1563 ovsdb_jsonrpc_disable_monitor_cond(void)
1564 {
1565     /* Once disabled, it is not possible to re-enable it. */
1566     monitor_cond_enable__ = false;
1567 }