ovsdb/jsonrpc-server.c

   1 /* Copyright (c) 2009, 2010, 2011 Nicira Networks
   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 <assert.h>
  21 #include <errno.h>
  22
  23 #include "bitmap.h"
  24 #include "column.h"
  25 #include "dynamic-string.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 "reconnect.h"
  32 #include "row.h"
  33 #include "server.h"
  34 #include "stream.h"
  35 #include "table.h"
  36 #include "timeval.h"
  37 #include "transaction.h"
  38 #include "trigger.h"
  39 #include "vlog.h"
  40
  41 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
  42
  43 struct ovsdb_jsonrpc_remote;
  44 struct ovsdb_jsonrpc_session;
  45
  46 /* Message rate-limiting. */
  47 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  48
  49 /* Sessions. */
  50 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  51     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  52 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  53 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  54 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  55 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  56 static void ovsdb_jsonrpc_session_set_all_options(
  57     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  58 static bool ovsdb_jsonrpc_session_get_status(
  59     const struct ovsdb_jsonrpc_remote *,
  60     struct ovsdb_jsonrpc_remote_status *);
  61 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  62 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  63
  64 /* Triggers. */
  65 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  66                                          struct json *id, struct json *params);
  67 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  68     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  69 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  70 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  71 static void ovsdb_jsonrpc_trigger_complete_done(
  72     struct ovsdb_jsonrpc_session *);
  73
  74 /* Monitors. */
  75 static struct json *ovsdb_jsonrpc_monitor_create(
  76     struct ovsdb_jsonrpc_session *, struct json *params);
  77 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  78     struct ovsdb_jsonrpc_session *,
  79     struct json_array *params,
  80     const struct json *request_id);
  81 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
  82 \f
  83 /* JSON-RPC database server. */
  84
  85 struct ovsdb_jsonrpc_server {
  86     struct ovsdb_server up;
  87     unsigned int n_sessions, max_sessions;
  88     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
  89 };
  90
  91 /* A configured remote.  This is either a passive stream listener plus a list
  92  * of the currently connected sessions, or a list of exactly one active
  93  * session. */
  94 struct ovsdb_jsonrpc_remote {
  95     struct ovsdb_jsonrpc_server *server;
  96     struct pstream *listener;   /* Listener, if passive. */
  97     struct list sessions;       /* List of "struct ovsdb_jsonrpc_session"s. */
  98 };
  99
 100 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 101     struct ovsdb_jsonrpc_server *, const char *name);
 102 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 103
 104 struct ovsdb_jsonrpc_server *
 105 ovsdb_jsonrpc_server_create(struct ovsdb *db)
 106 {
 107     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 108     ovsdb_server_init(&server->up, db);
 109     server->max_sessions = 64;
 110     shash_init(&server->remotes);
 111     return server;
 112 }
 113
 114 void
 115 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 116 {
 117     struct shash_node *node, *next;
 118
 119     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 120         ovsdb_jsonrpc_server_del_remote(node);
 121     }
 122     shash_destroy(&svr->remotes);
 123     ovsdb_server_destroy(&svr->up);
 124     free(svr);
 125 }
 126
 127 struct ovsdb_jsonrpc_options *
 128 ovsdb_jsonrpc_default_options(void)
 129 {
 130     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 131     options->probe_interval = RECONNECT_DEFAULT_PROBE_INTERVAL;
 132     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 133     return options;
 134 }
 135
 136 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 137  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 138  *
 139  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 140  * "tcp:1.2.3.4". */
 141 void
 142 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 143                                  const struct shash *new_remotes)
 144 {
 145     struct shash_node *node, *next;
 146
 147     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 148         if (!shash_find(new_remotes, node->name)) {
 149             VLOG_INFO("%s: remote deconfigured", node->name);
 150             ovsdb_jsonrpc_server_del_remote(node);
 151         }
 152     }
 153     SHASH_FOR_EACH (node, new_remotes) {
 154         const struct ovsdb_jsonrpc_options *options = node->data;
 155         struct ovsdb_jsonrpc_remote *remote;
 156
 157         remote = shash_find_data(&svr->remotes, node->name);
 158         if (!remote) {
 159             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name);
 160             if (!remote) {
 161                 continue;
 162             }
 163         }
 164
 165         ovsdb_jsonrpc_session_set_all_options(remote, options);
 166     }
 167 }
 168
 169 static struct ovsdb_jsonrpc_remote *
 170 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 171                                 const char *name)
 172 {
 173     struct ovsdb_jsonrpc_remote *remote;
 174     struct pstream *listener;
 175     int error;
 176
 177     error = jsonrpc_pstream_open(name, &listener);
 178     if (error && error != EAFNOSUPPORT) {
 179         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, strerror(error));
 180         return NULL;
 181     }
 182
 183     remote = xmalloc(sizeof *remote);
 184     remote->server = svr;
 185     remote->listener = listener;
 186     list_init(&remote->sessions);
 187     shash_add(&svr->remotes, name, remote);
 188
 189     if (!listener) {
 190         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name));
 191     }
 192     return remote;
 193 }
 194
 195 static void
 196 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 197 {
 198     struct ovsdb_jsonrpc_remote *remote = node->data;
 199
 200     ovsdb_jsonrpc_session_close_all(remote);
 201     pstream_close(remote->listener);
 202     shash_delete(&remote->server->remotes, node);
 203     free(remote);
 204 }
 205
 206 /* Stores status information for the remote named 'target', which should have
 207  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 208  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 209  * a remote named 'target' or if that remote is an inbound remote that has no
 210  * active connections) returns false.  On failure, 'status' will be zeroed.
 211  */
 212 bool
 213 ovsdb_jsonrpc_server_get_remote_status(
 214     const struct ovsdb_jsonrpc_server *svr, const char *target,
 215     struct ovsdb_jsonrpc_remote_status *status)
 216 {
 217     const struct ovsdb_jsonrpc_remote *remote;
 218
 219     memset(status, 0, sizeof *status);
 220
 221     remote = shash_find_data(&svr->remotes, target);
 222     return remote && ovsdb_jsonrpc_session_get_status(remote, status);
 223 }
 224
 225 void
 226 ovsdb_jsonrpc_server_free_remote_status(
 227     struct ovsdb_jsonrpc_remote_status *status)
 228 {
 229     free(status->locks_held);
 230     free(status->locks_waiting);
 231     free(status->locks_lost);
 232 }
 233
 234 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 235  * reconnect. */
 236 void
 237 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 238 {
 239     struct shash_node *node;
 240
 241     SHASH_FOR_EACH (node, &svr->remotes) {
 242         struct ovsdb_jsonrpc_remote *remote = node->data;
 243
 244         ovsdb_jsonrpc_session_reconnect_all(remote);
 245     }
 246 }
 247
 248 void
 249 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 250 {
 251     struct shash_node *node;
 252
 253     SHASH_FOR_EACH (node, &svr->remotes) {
 254         struct ovsdb_jsonrpc_remote *remote = node->data;
 255
 256         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 257             struct stream *stream;
 258             int error;
 259
 260             error = pstream_accept(remote->listener, &stream);
 261             if (!error) {
 262                 struct jsonrpc_session *js;
 263                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream));
 264                 ovsdb_jsonrpc_session_create(remote, js);
 265             } else if (error != EAGAIN) {
 266                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 267                              pstream_get_name(remote->listener),
 268                              strerror(error));
 269             }
 270         }
 271
 272         ovsdb_jsonrpc_session_run_all(remote);
 273     }
 274 }
 275
 276 void
 277 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 278 {
 279     struct shash_node *node;
 280
 281     SHASH_FOR_EACH (node, &svr->remotes) {
 282         struct ovsdb_jsonrpc_remote *remote = node->data;
 283
 284         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 285             pstream_wait(remote->listener);
 286         }
 287
 288         ovsdb_jsonrpc_session_wait_all(remote);
 289     }
 290 }
 291 \f
 292 /* JSON-RPC database server session. */
 293
 294 struct ovsdb_jsonrpc_session {
 295     struct ovsdb_session up;
 296     struct ovsdb_jsonrpc_remote *remote;
 297     struct list node;           /* Element in remote's sessions list. */
 298
 299     /* Triggers. */
 300     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 301
 302     /* Monitors. */
 303     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 304
 305     /* Network connectivity. */
 306     struct jsonrpc_session *js;  /* JSON-RPC session. */
 307     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 308 };
 309
 310 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 311 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 312 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 313 static void ovsdb_jsonrpc_session_set_options(
 314     struct ovsdb_jsonrpc_session *, const struct ovsdb_jsonrpc_options *);
 315 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 316                                              struct jsonrpc_msg *);
 317 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 318                                              struct jsonrpc_msg *);
 319
 320 static struct ovsdb_jsonrpc_session *
 321 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 322                              struct jsonrpc_session *js)
 323 {
 324     struct ovsdb_jsonrpc_session *s;
 325
 326     s = xzalloc(sizeof *s);
 327     ovsdb_session_init(&s->up, remote->server->up.db);
 328     s->remote = remote;
 329     list_push_back(&remote->sessions, &s->node);
 330     hmap_init(&s->triggers);
 331     hmap_init(&s->monitors);
 332     s->js = js;
 333     s->js_seqno = jsonrpc_session_get_seqno(js);
 334
 335     remote->server->n_sessions++;
 336
 337     return s;
 338 }
 339
 340 static void
 341 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 342 {
 343     ovsdb_jsonrpc_monitor_remove_all(s);
 344     ovsdb_jsonrpc_session_unlock_all(s);
 345     jsonrpc_session_close(s->js);
 346     list_remove(&s->node);
 347     ovsdb_session_destroy(&s->up);
 348     s->remote->server->n_sessions--;
 349     ovsdb_session_destroy(&s->up);
 350     free(s);
 351 }
 352
 353 static int
 354 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 355 {
 356     jsonrpc_session_run(s->js);
 357     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 358         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 359         ovsdb_jsonrpc_trigger_complete_all(s);
 360         ovsdb_jsonrpc_monitor_remove_all(s);
 361         ovsdb_jsonrpc_session_unlock_all(s);
 362     }
 363
 364     ovsdb_jsonrpc_trigger_complete_done(s);
 365
 366     if (!jsonrpc_session_get_backlog(s->js)) {
 367         struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
 368         if (msg) {
 369             if (msg->type == JSONRPC_REQUEST) {
 370                 ovsdb_jsonrpc_session_got_request(s, msg);
 371             } else if (msg->type == JSONRPC_NOTIFY) {
 372                 ovsdb_jsonrpc_session_got_notify(s, msg);
 373             } else {
 374                 VLOG_WARN("%s: received unexpected %s message",
 375                           jsonrpc_session_get_name(s->js),
 376                           jsonrpc_msg_type_to_string(msg->type));
 377                 jsonrpc_session_force_reconnect(s->js);
 378                 jsonrpc_msg_destroy(msg);
 379             }
 380         }
 381     }
 382     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 383 }
 384
 385 static void
 386 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 387                                   const struct ovsdb_jsonrpc_options *options)
 388 {
 389     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 390     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 391 }
 392
 393 static void
 394 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 395 {
 396     struct ovsdb_jsonrpc_session *s, *next;
 397
 398     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 399         int error = ovsdb_jsonrpc_session_run(s);
 400         if (error) {
 401             ovsdb_jsonrpc_session_close(s);
 402         }
 403     }
 404 }
 405
 406 static void
 407 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 408 {
 409     jsonrpc_session_wait(s->js);
 410     if (!jsonrpc_session_get_backlog(s->js)) {
 411         jsonrpc_session_recv_wait(s->js);
 412     }
 413 }
 414
 415 static void
 416 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 417 {
 418     struct ovsdb_jsonrpc_session *s;
 419
 420     LIST_FOR_EACH (s, node, &remote->sessions) {
 421         ovsdb_jsonrpc_session_wait(s);
 422     }
 423 }
 424
 425 static void
 426 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 427 {
 428     struct ovsdb_jsonrpc_session *s, *next;
 429
 430     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 431         ovsdb_jsonrpc_session_close(s);
 432     }
 433 }
 434
 435 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 436  * reconnect. */
 437 static void
 438 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 439 {
 440     struct ovsdb_jsonrpc_session *s, *next;
 441
 442     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 443         jsonrpc_session_force_reconnect(s->js);
 444         if (!jsonrpc_session_is_alive(s->js)) {
 445             ovsdb_jsonrpc_session_close(s);
 446         }
 447     }
 448 }
 449
 450 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 451  * 'options'. */
 452 static void
 453 ovsdb_jsonrpc_session_set_all_options(
 454     struct ovsdb_jsonrpc_remote *remote,
 455     const struct ovsdb_jsonrpc_options *options)
 456 {
 457     struct ovsdb_jsonrpc_session *s;
 458
 459     LIST_FOR_EACH (s, node, &remote->sessions) {
 460         ovsdb_jsonrpc_session_set_options(s, options);
 461     }
 462 }
 463
 464 static bool
 465 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
 466                                  struct ovsdb_jsonrpc_remote_status *status)
 467 {
 468     const struct ovsdb_jsonrpc_session *s;
 469     const struct jsonrpc_session *js;
 470     struct ovsdb_lock_waiter *waiter;
 471     struct reconnect_stats rstats;
 472     struct ds locks_held, locks_waiting, locks_lost;
 473
 474     if (list_is_empty(&remote->sessions)) {
 475         return false;
 476     }
 477     s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
 478     js = s->js;
 479
 480     status->is_connected = jsonrpc_session_is_connected(js);
 481     status->last_error = jsonrpc_session_get_status(js);
 482
 483     jsonrpc_session_get_reconnect_stats(js, &rstats);
 484     status->state = rstats.state;
 485     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 486         ? UINT_MAX : rstats.msec_since_connect / 1000;
 487     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 488         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 489
 490     ds_init(&locks_held);
 491     ds_init(&locks_waiting);
 492     ds_init(&locks_lost);
 493     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 494         struct ds *string;
 495
 496         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 497                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 498                   : &locks_lost);
 499         if (string->length) {
 500             ds_put_char(string, ' ');
 501         }
 502         ds_put_cstr(string, waiter->lock_name);
 503     }
 504     status->locks_held = ds_steal_cstr(&locks_held);
 505     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 506     status->locks_lost = ds_steal_cstr(&locks_lost);
 507
 508     status->n_connections = list_size(&remote->sessions);
 509
 510     return true;
 511 }
 512
 513 static const char *
 514 get_db_name(const struct ovsdb_jsonrpc_session *s)
 515 {
 516     return s->remote->server->up.db->schema->name;
 517 }
 518
 519 static struct jsonrpc_msg *
 520 ovsdb_jsonrpc_check_db_name(const struct ovsdb_jsonrpc_session *s,
 521                             const struct jsonrpc_msg *request)
 522 {
 523     struct json_array *params;
 524     const char *want_db_name;
 525     const char *have_db_name;
 526     struct ovsdb_error *error;
 527     struct jsonrpc_msg *reply;
 528
 529     params = json_array(request->params);
 530     if (!params->n || params->elems[0]->type != JSON_STRING) {
 531         error = ovsdb_syntax_error(
 532             request->params, NULL,
 533             "%s request params must begin with <db-name>", request->method);
 534         goto error;
 535     }
 536
 537     want_db_name = params->elems[0]->u.string;
 538     have_db_name = get_db_name(s);
 539     if (strcmp(want_db_name, have_db_name)) {
 540         error = ovsdb_syntax_error(
 541             request->params, "unknown database",
 542             "%s request specifies unknown database %s",
 543             request->method, want_db_name);
 544         goto error;
 545     }
 546
 547     return NULL;
 548
 549 error:
 550     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 551     ovsdb_error_destroy(error);
 552     return reply;
 553 }
 554
 555 static struct ovsdb_error *
 556 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 557                                       const char **lock_namep)
 558 {
 559     const struct json_array *params;
 560
 561     params = json_array(request->params);
 562     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 563         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 564         *lock_namep = NULL;
 565         return ovsdb_syntax_error(request->params, NULL,
 566                                   "%s request params must be <id>",
 567                                   request->method);
 568     }
 569
 570     *lock_namep = json_string(params->elems[0]);
 571     return NULL;
 572 }
 573
 574 static void
 575 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 576                              const char *lock_name,
 577                              const char *method)
 578 {
 579     struct ovsdb_jsonrpc_session *s;
 580     struct json *params;
 581
 582     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 583     params = json_array_create_1(json_string_create(lock_name));
 584     jsonrpc_session_send(s->js, jsonrpc_create_notify(method, params));
 585 }
 586
 587 static struct jsonrpc_msg *
 588 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 589                            struct jsonrpc_msg *request,
 590                            enum ovsdb_lock_mode mode)
 591 {
 592     struct ovsdb_lock_waiter *waiter;
 593     struct jsonrpc_msg *reply;
 594     struct ovsdb_error *error;
 595     struct ovsdb_session *victim;
 596     const char *lock_name;
 597     struct json *result;
 598
 599     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 600     if (error) {
 601         goto error;
 602     }
 603
 604     /* Report error if this session has issued a "lock" or "steal" without a
 605      * matching "unlock" for this lock. */
 606     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 607     if (waiter) {
 608         error = ovsdb_syntax_error(
 609             request->params, NULL,
 610             "must issue \"unlock\" before new \"%s\"", request->method);
 611         goto error;
 612     }
 613
 614     /* Get the lock, add us as a waiter. */
 615     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 616                                &victim);
 617     if (victim) {
 618         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 619     }
 620
 621     result = json_object_create();
 622     json_object_put(result, "locked",
 623                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 624
 625     return jsonrpc_create_reply(result, request->id);
 626
 627 error:
 628     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 629     ovsdb_error_destroy(error);
 630     return reply;
 631 }
 632
 633 static void
 634 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 635 {
 636     struct ovsdb_lock_waiter *waiter, *next;
 637
 638     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 639         ovsdb_jsonrpc_session_unlock__(waiter);
 640     }
 641 }
 642
 643 static void
 644 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 645 {
 646     struct ovsdb_lock *lock = waiter->lock;
 647
 648     if (lock) {
 649         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 650         if (new_owner) {
 651             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 652         } else {
 653             /* ovsdb_server_lock() might have freed 'lock'. */
 654         }
 655     }
 656
 657     ovsdb_lock_waiter_destroy(waiter);
 658 }
 659
 660 static struct jsonrpc_msg *
 661 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 662                              struct jsonrpc_msg *request)
 663 {
 664     struct ovsdb_lock_waiter *waiter;
 665     struct jsonrpc_msg *reply;
 666     struct ovsdb_error *error;
 667     const char *lock_name;
 668
 669     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 670     if (error) {
 671         goto error;
 672     }
 673
 674     /* Report error if this session has not issued a "lock" or "steal" for this
 675      * lock. */
 676     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 677     if (!waiter) {
 678         error = ovsdb_syntax_error(
 679             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 680         goto error;
 681     }
 682
 683     ovsdb_jsonrpc_session_unlock__(waiter);
 684
 685     return jsonrpc_create_reply(json_object_create(), request->id);
 686
 687 error:
 688     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 689     ovsdb_error_destroy(error);
 690     return reply;
 691 }
 692
 693 static struct jsonrpc_msg *
 694 execute_transaction(struct ovsdb_jsonrpc_session *s,
 695                     struct jsonrpc_msg *request)
 696 {
 697     ovsdb_jsonrpc_trigger_create(s, request->id, request->params);
 698     request->id = NULL;
 699     request->params = NULL;
 700     jsonrpc_msg_destroy(request);
 701     return NULL;
 702 }
 703
 704 static void
 705 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 706                                   struct jsonrpc_msg *request)
 707 {
 708     struct jsonrpc_msg *reply;
 709
 710     if (!strcmp(request->method, "transact")) {
 711         reply = ovsdb_jsonrpc_check_db_name(s, request);
 712         if (!reply) {
 713             reply = execute_transaction(s, request);
 714         }
 715     } else if (!strcmp(request->method, "monitor")) {
 716         reply = ovsdb_jsonrpc_check_db_name(s, request);
 717         if (!reply) {
 718             reply = jsonrpc_create_reply(
 719                 ovsdb_jsonrpc_monitor_create(s, request->params), request->id);
 720         }
 721     } else if (!strcmp(request->method, "monitor_cancel")) {
 722         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 723                                              request->id);
 724     } else if (!strcmp(request->method, "get_schema")) {
 725         reply = ovsdb_jsonrpc_check_db_name(s, request);
 726         if (!reply) {
 727             reply = jsonrpc_create_reply(
 728                 ovsdb_schema_to_json(s->remote->server->up.db->schema),
 729                 request->id);
 730         }
 731     } else if (!strcmp(request->method, "list_dbs")) {
 732         reply = jsonrpc_create_reply(
 733             json_array_create_1(json_string_create(get_db_name(s))),
 734             request->id);
 735     } else if (!strcmp(request->method, "lock")) {
 736         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 737     } else if (!strcmp(request->method, "steal")) {
 738         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 739     } else if (!strcmp(request->method, "unlock")) {
 740         reply = ovsdb_jsonrpc_session_unlock(s, request);
 741     } else if (!strcmp(request->method, "echo")) {
 742         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 743     } else {
 744         reply = jsonrpc_create_error(json_string_create("unknown method"),
 745                                      request->id);
 746     }
 747
 748     if (reply) {
 749         jsonrpc_msg_destroy(request);
 750         jsonrpc_session_send(s->js, reply);
 751     }
 752 }
 753
 754 static void
 755 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 756 {
 757     if (json_array(request->params)->n == 1) {
 758         struct ovsdb_jsonrpc_trigger *t;
 759         struct json *id;
 760
 761         id = request->params->u.array.elems[0];
 762         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 763         if (t) {
 764             ovsdb_jsonrpc_trigger_complete(t);
 765         }
 766     }
 767 }
 768
 769 static void
 770 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 771                                  struct jsonrpc_msg *request)
 772 {
 773     if (!strcmp(request->method, "cancel")) {
 774         execute_cancel(s, request);
 775     }
 776     jsonrpc_msg_destroy(request);
 777 }
 778 \f
 779 /* JSON-RPC database server triggers.
 780  *
 781  * (Every transaction is treated as a trigger even if it doesn't actually have
 782  * any "wait" operations.) */
 783
 784 struct ovsdb_jsonrpc_trigger {
 785     struct ovsdb_trigger trigger;
 786     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 787     struct json *id;
 788 };
 789
 790 static void
 791 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s,
 792                              struct json *id, struct json *params)
 793 {
 794     struct ovsdb_jsonrpc_trigger *t;
 795     size_t hash;
 796
 797     /* Check for duplicate ID. */
 798     hash = json_hash(id, 0);
 799     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 800     if (t) {
 801         struct jsonrpc_msg *msg;
 802
 803         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 804                                    id);
 805         jsonrpc_session_send(s->js, msg);
 806         json_destroy(id);
 807         json_destroy(params);
 808         return;
 809     }
 810
 811     /* Insert into trigger table. */
 812     t = xmalloc(sizeof *t);
 813     ovsdb_trigger_init(&s->up, &t->trigger, params, time_msec());
 814     t->id = id;
 815     hmap_insert(&s->triggers, &t->hmap_node, hash);
 816
 817     /* Complete early if possible. */
 818     if (ovsdb_trigger_is_complete(&t->trigger)) {
 819         ovsdb_jsonrpc_trigger_complete(t);
 820     }
 821 }
 822
 823 static struct ovsdb_jsonrpc_trigger *
 824 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 825                            const struct json *id, size_t hash)
 826 {
 827     struct ovsdb_jsonrpc_trigger *t;
 828
 829     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
 830         if (json_equal(t->id, id)) {
 831             return t;
 832         }
 833     }
 834
 835     return NULL;
 836 }
 837
 838 static void
 839 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 840 {
 841     struct ovsdb_jsonrpc_session *s;
 842
 843     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 844
 845     if (jsonrpc_session_is_connected(s->js)) {
 846         struct jsonrpc_msg *reply;
 847         struct json *result;
 848
 849         result = ovsdb_trigger_steal_result(&t->trigger);
 850         if (result) {
 851             reply = jsonrpc_create_reply(result, t->id);
 852         } else {
 853             reply = jsonrpc_create_error(json_string_create("canceled"),
 854                                          t->id);
 855         }
 856         jsonrpc_session_send(s->js, reply);
 857     }
 858
 859     json_destroy(t->id);
 860     ovsdb_trigger_destroy(&t->trigger);
 861     hmap_remove(&s->triggers, &t->hmap_node);
 862     free(t);
 863 }
 864
 865 static void
 866 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
 867 {
 868     struct ovsdb_jsonrpc_trigger *t, *next;
 869     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
 870         ovsdb_jsonrpc_trigger_complete(t);
 871     }
 872 }
 873
 874 static void
 875 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
 876 {
 877     while (!list_is_empty(&s->up.completions)) {
 878         struct ovsdb_jsonrpc_trigger *t
 879             = CONTAINER_OF(s->up.completions.next,
 880                            struct ovsdb_jsonrpc_trigger, trigger.node);
 881         ovsdb_jsonrpc_trigger_complete(t);
 882     }
 883 }
 884 \f
 885 /* JSON-RPC database table monitors. */
 886
 887 enum ovsdb_jsonrpc_monitor_selection {
 888     OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
 889     OJMS_INSERT = 1 << 1,       /* New rows. */
 890     OJMS_DELETE = 1 << 2,       /* Deleted rows. */
 891     OJMS_MODIFY = 1 << 3        /* Modified rows. */
 892 };
 893
 894 /* A particular column being monitored. */
 895 struct ovsdb_jsonrpc_monitor_column {
 896     const struct ovsdb_column *column;
 897     enum ovsdb_jsonrpc_monitor_selection select;
 898 };
 899
 900 /* A particular table being monitored. */
 901 struct ovsdb_jsonrpc_monitor_table {
 902     const struct ovsdb_table *table;
 903
 904     /* This is the union (bitwise-OR) of the 'select' values in all of the
 905      * members of 'columns' below. */
 906     enum ovsdb_jsonrpc_monitor_selection select;
 907
 908     /* Columns being monitored. */
 909     struct ovsdb_jsonrpc_monitor_column *columns;
 910     size_t n_columns;
 911 };
 912
 913 /* A collection of tables being monitored. */
 914 struct ovsdb_jsonrpc_monitor {
 915     struct ovsdb_replica replica;
 916     struct ovsdb_jsonrpc_session *session;
 917     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
 918
 919     struct json *monitor_id;
 920     struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
 921 };
 922
 923 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
 924
 925 struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
 926     struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
 927 static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
 928 static struct json *ovsdb_jsonrpc_monitor_get_initial(
 929     const struct ovsdb_jsonrpc_monitor *);
 930
 931 static bool
 932 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
 933 {
 934     const struct json *json;
 935
 936     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
 937     return json ? json_boolean(json) : default_value;
 938 }
 939
 940 struct ovsdb_jsonrpc_monitor *
 941 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
 942                            const struct json *monitor_id)
 943 {
 944     struct ovsdb_jsonrpc_monitor *m;
 945
 946     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
 947         if (json_equal(m->monitor_id, monitor_id)) {
 948             return m;
 949         }
 950     }
 951
 952     return NULL;
 953 }
 954
 955 static void
 956 ovsdb_jsonrpc_add_monitor_column(struct ovsdb_jsonrpc_monitor_table *mt,
 957                                  const struct ovsdb_column *column,
 958                                  enum ovsdb_jsonrpc_monitor_selection select,
 959                                  size_t *allocated_columns)
 960 {
 961     struct ovsdb_jsonrpc_monitor_column *c;
 962
 963     if (mt->n_columns >= *allocated_columns) {
 964         mt->columns = x2nrealloc(mt->columns, allocated_columns,
 965                                  sizeof *mt->columns);
 966     }
 967
 968     c = &mt->columns[mt->n_columns++];
 969     c->column = column;
 970     c->select = select;
 971 }
 972
 973 static int
 974 compare_ovsdb_jsonrpc_monitor_column(const void *a_, const void *b_)
 975 {
 976     const struct ovsdb_jsonrpc_monitor_column *a = a_;
 977     const struct ovsdb_jsonrpc_monitor_column *b = b_;
 978
 979     return a->column < b->column ? -1 : a->column > b->column;
 980 }
 981
 982 static struct ovsdb_error * WARN_UNUSED_RESULT
 983 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
 984                                     const struct json *monitor_request,
 985                                     size_t *allocated_columns)
 986 {
 987     const struct ovsdb_table_schema *ts = mt->table->schema;
 988     enum ovsdb_jsonrpc_monitor_selection select;
 989     const struct json *columns, *select_json;
 990     struct ovsdb_parser parser;
 991     struct ovsdb_error *error;
 992
 993     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
 994     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
 995     select_json = ovsdb_parser_member(&parser, "select",
 996                                       OP_OBJECT | OP_OPTIONAL);
 997     error = ovsdb_parser_finish(&parser);
 998     if (error) {
 999         return error;
1000     }
1001
1002     if (select_json) {
1003         select = 0;
1004         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1005         if (parse_bool(&parser, "initial", true)) {
1006             select |= OJMS_INITIAL;
1007         }
1008         if (parse_bool(&parser, "insert", true)) {
1009             select |= OJMS_INSERT;
1010         }
1011         if (parse_bool(&parser, "delete", true)) {
1012             select |= OJMS_DELETE;
1013         }
1014         if (parse_bool(&parser, "modify", true)) {
1015             select |= OJMS_MODIFY;
1016         }
1017         error = ovsdb_parser_finish(&parser);
1018         if (error) {
1019             return error;
1020         }
1021     } else {
1022         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1023     }
1024     mt->select |= select;
1025
1026     if (columns) {
1027         size_t i;
1028
1029         if (columns->type != JSON_ARRAY) {
1030             return ovsdb_syntax_error(columns, NULL,
1031                                       "array of column names expected");
1032         }
1033
1034         for (i = 0; i < columns->u.array.n; i++) {
1035             const struct ovsdb_column *column;
1036             const char *s;
1037
1038             if (columns->u.array.elems[i]->type != JSON_STRING) {
1039                 return ovsdb_syntax_error(columns, NULL,
1040                                           "array of column names expected");
1041             }
1042
1043             s = columns->u.array.elems[i]->u.string;
1044             column = shash_find_data(&mt->table->schema->columns, s);
1045             if (!column) {
1046                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1047                                           "column name", s);
1048             }
1049             ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1050                                              allocated_columns);
1051         }
1052     } else {
1053         struct shash_node *node;
1054
1055         SHASH_FOR_EACH (node, &ts->columns) {
1056             const struct ovsdb_column *column = node->data;
1057             if (column->index != OVSDB_COL_UUID) {
1058                 ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1059                                                  allocated_columns);
1060             }
1061         }
1062     }
1063
1064     return NULL;
1065 }
1066
1067 static struct json *
1068 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s,
1069                              struct json *params)
1070 {
1071     struct ovsdb_jsonrpc_monitor *m = NULL;
1072     struct json *monitor_id, *monitor_requests;
1073     struct ovsdb_error *error = NULL;
1074     struct shash_node *node;
1075     struct json *json;
1076
1077     if (json_array(params)->n != 3) {
1078         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1079         goto error;
1080     }
1081     monitor_id = params->u.array.elems[1];
1082     monitor_requests = params->u.array.elems[2];
1083     if (monitor_requests->type != JSON_OBJECT) {
1084         error = ovsdb_syntax_error(monitor_requests, NULL,
1085                                    "monitor-requests must be object");
1086         goto error;
1087     }
1088
1089     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1090         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1091         goto error;
1092     }
1093
1094     m = xzalloc(sizeof *m);
1095     ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
1096     ovsdb_add_replica(s->remote->server->up.db, &m->replica);
1097     m->session = s;
1098     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1099     m->monitor_id = json_clone(monitor_id);
1100     shash_init(&m->tables);
1101
1102     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1103         const struct ovsdb_table *table;
1104         struct ovsdb_jsonrpc_monitor_table *mt;
1105         size_t allocated_columns;
1106         const struct json *mr_value;
1107         size_t i;
1108
1109         table = ovsdb_get_table(s->remote->server->up.db, node->name);
1110         if (!table) {
1111             error = ovsdb_syntax_error(NULL, NULL,
1112                                        "no table named %s", node->name);
1113             goto error;
1114         }
1115
1116         mt = xzalloc(sizeof *mt);
1117         mt->table = table;
1118         shash_add(&m->tables, table->schema->name, mt);
1119
1120         /* Parse columns. */
1121         mr_value = node->data;
1122         allocated_columns = 0;
1123         if (mr_value->type == JSON_ARRAY) {
1124             const struct json_array *array = &mr_value->u.array;
1125
1126             for (i = 0; i < array->n; i++) {
1127                 error = ovsdb_jsonrpc_parse_monitor_request(
1128                     mt, array->elems[i], &allocated_columns);
1129                 if (error) {
1130                     goto error;
1131                 }
1132             }
1133         } else {
1134             error = ovsdb_jsonrpc_parse_monitor_request(
1135                 mt, mr_value, &allocated_columns);
1136             if (error) {
1137                 goto error;
1138             }
1139         }
1140
1141         /* Check for duplicate columns. */
1142         qsort(mt->columns, mt->n_columns, sizeof *mt->columns,
1143               compare_ovsdb_jsonrpc_monitor_column);
1144         for (i = 1; i < mt->n_columns; i++) {
1145             if (mt->columns[i].column == mt->columns[i - 1].column) {
1146                 error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1147                                            "mentioned more than once",
1148                                            mt->columns[i].column->name);
1149                 goto error;
1150             }
1151         }
1152     }
1153
1154     return ovsdb_jsonrpc_monitor_get_initial(m);
1155
1156 error:
1157     if (m) {
1158         ovsdb_remove_replica(s->remote->server->up.db, &m->replica);
1159     }
1160
1161     json = ovsdb_error_to_json(error);
1162     ovsdb_error_destroy(error);
1163     return json;
1164 }
1165
1166 static struct jsonrpc_msg *
1167 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1168                              struct json_array *params,
1169                              const struct json *request_id)
1170 {
1171     if (params->n != 1) {
1172         return jsonrpc_create_error(json_string_create("invalid parameters"),
1173                                     request_id);
1174     } else {
1175         struct ovsdb_jsonrpc_monitor *m;
1176
1177         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1178         if (!m) {
1179             return jsonrpc_create_error(json_string_create("unknown monitor"),
1180                                         request_id);
1181         } else {
1182             ovsdb_remove_replica(s->remote->server->up.db, &m->replica);
1183             return jsonrpc_create_reply(json_object_create(), request_id);
1184         }
1185     }
1186 }
1187
1188 static void
1189 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1190 {
1191     struct ovsdb_jsonrpc_monitor *m, *next;
1192
1193     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1194         ovsdb_remove_replica(s->remote->server->up.db, &m->replica);
1195     }
1196 }
1197
1198 static struct ovsdb_jsonrpc_monitor *
1199 ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
1200 {
1201     assert(replica->class == &ovsdb_jsonrpc_replica_class);
1202     return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
1203 }
1204
1205 struct ovsdb_jsonrpc_monitor_aux {
1206     bool initial;               /* Sending initial contents of table? */
1207     const struct ovsdb_jsonrpc_monitor *monitor;
1208     struct json *json;          /* JSON for the whole transaction. */
1209
1210     /* Current table.  */
1211     struct ovsdb_jsonrpc_monitor_table *mt;
1212     struct json *table_json;    /* JSON for table's transaction. */
1213 };
1214
1215 static bool
1216 any_reportable_change(const struct ovsdb_jsonrpc_monitor_table *mt,
1217                       const unsigned long int *changed)
1218 {
1219     size_t i;
1220
1221     for (i = 0; i < mt->n_columns; i++) {
1222         const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1223         unsigned int idx = c->column->index;
1224
1225         if (c->select & OJMS_MODIFY && bitmap_is_set(changed, idx)) {
1226             return true;
1227         }
1228     }
1229
1230     return false;
1231 }
1232
1233 static bool
1234 ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
1235                                 const struct ovsdb_row *new,
1236                                 const unsigned long int *changed,
1237                                 void *aux_)
1238 {
1239     struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
1240     const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
1241     struct ovsdb_table *table = new ? new->table : old->table;
1242     enum ovsdb_jsonrpc_monitor_selection type;
1243     struct json *old_json, *new_json;
1244     struct json *row_json;
1245     char uuid[UUID_LEN + 1];
1246     size_t i;
1247
1248     if (!aux->mt || table != aux->mt->table) {
1249         aux->mt = shash_find_data(&m->tables, table->schema->name);
1250         aux->table_json = NULL;
1251         if (!aux->mt) {
1252             /* We don't care about rows in this table at all.  Tell the caller
1253              * to skip it.  */
1254             return false;
1255         }
1256     }
1257
1258     type = (aux->initial ? OJMS_INITIAL
1259             : !old ? OJMS_INSERT
1260             : !new ? OJMS_DELETE
1261             : OJMS_MODIFY);
1262     if (!(aux->mt->select & type)) {
1263         /* We don't care about this type of change (but do want to be called
1264          * back for changes to other rows in the same table). */
1265         return true;
1266     }
1267
1268     if (type == OJMS_MODIFY && !any_reportable_change(aux->mt, changed)) {
1269         /* Nothing of interest changed. */
1270         return true;
1271     }
1272
1273     old_json = new_json = NULL;
1274     if (type & (OJMS_DELETE | OJMS_MODIFY)) {
1275         old_json = json_object_create();
1276     }
1277     if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1278         new_json = json_object_create();
1279     }
1280     for (i = 0; i < aux->mt->n_columns; i++) {
1281         const struct ovsdb_jsonrpc_monitor_column *c = &aux->mt->columns[i];
1282         const struct ovsdb_column *column = c->column;
1283         unsigned int idx = c->column->index;
1284
1285         if (!(type & c->select)) {
1286             /* We don't care about this type of change for this particular
1287              * column (but we will care about it for some other column). */
1288             continue;
1289         }
1290
1291         if ((type == OJMS_MODIFY && bitmap_is_set(changed, idx))
1292             || type == OJMS_DELETE) {
1293             json_object_put(old_json, column->name,
1294                             ovsdb_datum_to_json(&old->fields[idx],
1295                                                 &column->type));
1296         }
1297         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1298             json_object_put(new_json, column->name,
1299                             ovsdb_datum_to_json(&new->fields[idx],
1300                                                 &column->type));
1301         }
1302     }
1303
1304     /* Create JSON object for transaction overall. */
1305     if (!aux->json) {
1306         aux->json = json_object_create();
1307     }
1308
1309     /* Create JSON object for transaction on this table. */
1310     if (!aux->table_json) {
1311         aux->table_json = json_object_create();
1312         json_object_put(aux->json, aux->mt->table->schema->name,
1313                         aux->table_json);
1314     }
1315
1316     /* Create JSON object for transaction on this row. */
1317     row_json = json_object_create();
1318     if (old_json) {
1319         json_object_put(row_json, "old", old_json);
1320     }
1321     if (new_json) {
1322         json_object_put(row_json, "new", new_json);
1323     }
1324
1325     /* Add JSON row to JSON table. */
1326     snprintf(uuid, sizeof uuid,
1327              UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
1328     json_object_put(aux->table_json, uuid, row_json);
1329
1330     return true;
1331 }
1332
1333 static void
1334 ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
1335                                const struct ovsdb_jsonrpc_monitor *m,
1336                                bool initial)
1337 {
1338     aux->initial = initial;
1339     aux->monitor = m;
1340     aux->json = NULL;
1341     aux->mt = NULL;
1342     aux->table_json = NULL;
1343 }
1344
1345 static struct ovsdb_error *
1346 ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
1347                              const struct ovsdb_txn *txn,
1348                              bool durable OVS_UNUSED)
1349 {
1350     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1351     struct ovsdb_jsonrpc_monitor_aux aux;
1352
1353     ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
1354     ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
1355     if (aux.json) {
1356         struct jsonrpc_msg *msg;
1357         struct json *params;
1358
1359         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
1360                                      aux.json);
1361         msg = jsonrpc_create_notify("update", params);
1362         jsonrpc_session_send(aux.monitor->session->js, msg);
1363     }
1364
1365     return NULL;
1366 }
1367
1368 static struct json *
1369 ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
1370 {
1371     struct ovsdb_jsonrpc_monitor_aux aux;
1372     struct shash_node *node;
1373
1374     ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
1375     SHASH_FOR_EACH (node, &m->tables) {
1376         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1377
1378         if (mt->select & OJMS_INITIAL) {
1379             struct ovsdb_row *row;
1380
1381             HMAP_FOR_EACH (row, hmap_node, &mt->table->rows) {
1382                 ovsdb_jsonrpc_monitor_change_cb(NULL, row, NULL, &aux);
1383             }
1384         }
1385     }
1386     return aux.json ? aux.json : json_object_create();
1387 }
1388
1389 static void
1390 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
1391 {
1392     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1393     struct shash_node *node;
1394
1395     json_destroy(m->monitor_id);
1396     SHASH_FOR_EACH (node, &m->tables) {
1397         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1398         free(mt->columns);
1399         free(mt);
1400     }
1401     shash_destroy(&m->tables);
1402     hmap_remove(&m->session->monitors, &m->node);
1403     free(m);
1404 }
1405
1406 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
1407     ovsdb_jsonrpc_monitor_commit,
1408     ovsdb_jsonrpc_monitor_destroy
1409 };