ovsdb/jsonrpc-server.c

   1 /* Copyright (c) 2009, 2010, 2011, 2012 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 <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 "simap.h"
  35 #include "stream.h"
  36 #include "table.h"
  37 #include "timeval.h"
  38 #include "transaction.h"
  39 #include "trigger.h"
  40 #include "vlog.h"
  41
  42 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
  43
  44 struct ovsdb_jsonrpc_remote;
  45 struct ovsdb_jsonrpc_session;
  46
  47 /* Message rate-limiting. */
  48 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  49
  50 /* Sessions. */
  51 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  52     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  53 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  54 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  55 static void ovsdb_jsonrpc_session_get_memory_usage_all(
  56     const struct ovsdb_jsonrpc_remote *, struct simap *usage);
  57 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  58 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  59 static void ovsdb_jsonrpc_session_set_all_options(
  60     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  61 static bool ovsdb_jsonrpc_session_get_status(
  62     const struct ovsdb_jsonrpc_remote *,
  63     struct ovsdb_jsonrpc_remote_status *);
  64 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  65 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  66
  67 /* Triggers. */
  68 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  69                                          struct ovsdb *,
  70                                          struct json *id, struct json *params);
  71 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  72     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  73 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  74 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  75 static void ovsdb_jsonrpc_trigger_complete_done(
  76     struct ovsdb_jsonrpc_session *);
  77
  78 /* Monitors. */
  79 static struct json *ovsdb_jsonrpc_monitor_create(
  80     struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params);
  81 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  82     struct ovsdb_jsonrpc_session *,
  83     struct json_array *params,
  84     const struct json *request_id);
  85 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
  86 \f
  87 /* JSON-RPC database server. */
  88
  89 struct ovsdb_jsonrpc_server {
  90     struct ovsdb_server up;
  91     unsigned int n_sessions, max_sessions;
  92     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
  93 };
  94
  95 /* A configured remote.  This is either a passive stream listener plus a list
  96  * of the currently connected sessions, or a list of exactly one active
  97  * session. */
  98 struct ovsdb_jsonrpc_remote {
  99     struct ovsdb_jsonrpc_server *server;
 100     struct pstream *listener;   /* Listener, if passive. */
 101     struct list sessions;       /* List of "struct ovsdb_jsonrpc_session"s. */
 102 };
 103
 104 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 105     struct ovsdb_jsonrpc_server *, const char *name,
 106     const struct ovsdb_jsonrpc_options *options
 107 );
 108 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 109
 110 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 111  *
 112  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 113  * which 'server' should provide access. */
 114 struct ovsdb_jsonrpc_server *
 115 ovsdb_jsonrpc_server_create(void)
 116 {
 117     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 118     ovsdb_server_init(&server->up);
 119     server->max_sessions = 64;
 120     shash_init(&server->remotes);
 121     return server;
 122 }
 123
 124 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 125  * successful, false if 'db''s name is the same as some database already in
 126  * 'server'. */
 127 bool
 128 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 129 {
 130     return ovsdb_server_add_db(&svr->up, db);
 131 }
 132
 133 void
 134 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 135 {
 136     struct shash_node *node, *next;
 137
 138     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 139         ovsdb_jsonrpc_server_del_remote(node);
 140     }
 141     shash_destroy(&svr->remotes);
 142     ovsdb_server_destroy(&svr->up);
 143     free(svr);
 144 }
 145
 146 struct ovsdb_jsonrpc_options *
 147 ovsdb_jsonrpc_default_options(const char *target)
 148 {
 149     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 150     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 151     options->probe_interval = (stream_or_pstream_needs_probes(target)
 152                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 153                                : 0);
 154     return options;
 155 }
 156
 157 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 158  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 159  *
 160  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 161  * "tcp:1.2.3.4". */
 162 void
 163 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 164                                  const struct shash *new_remotes)
 165 {
 166     struct shash_node *node, *next;
 167
 168     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 169         if (!shash_find(new_remotes, node->name)) {
 170             VLOG_INFO("%s: remote deconfigured", node->name);
 171             ovsdb_jsonrpc_server_del_remote(node);
 172         }
 173     }
 174     SHASH_FOR_EACH (node, new_remotes) {
 175         const struct ovsdb_jsonrpc_options *options = node->data;
 176         struct ovsdb_jsonrpc_remote *remote;
 177
 178         remote = shash_find_data(&svr->remotes, node->name);
 179         if (!remote) {
 180             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 181             if (!remote) {
 182                 continue;
 183             }
 184         }
 185
 186         ovsdb_jsonrpc_session_set_all_options(remote, options);
 187     }
 188 }
 189
 190 static struct ovsdb_jsonrpc_remote *
 191 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 192                                 const char *name,
 193                                 const struct ovsdb_jsonrpc_options *options)
 194 {
 195     struct ovsdb_jsonrpc_remote *remote;
 196     struct pstream *listener;
 197     int error;
 198
 199     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 200     if (error && error != EAFNOSUPPORT) {
 201         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, strerror(error));
 202         return NULL;
 203     }
 204
 205     remote = xmalloc(sizeof *remote);
 206     remote->server = svr;
 207     remote->listener = listener;
 208     list_init(&remote->sessions);
 209     shash_add(&svr->remotes, name, remote);
 210
 211     if (!listener) {
 212         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name));
 213     }
 214     return remote;
 215 }
 216
 217 static void
 218 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 219 {
 220     struct ovsdb_jsonrpc_remote *remote = node->data;
 221
 222     ovsdb_jsonrpc_session_close_all(remote);
 223     pstream_close(remote->listener);
 224     shash_delete(&remote->server->remotes, node);
 225     free(remote);
 226 }
 227
 228 /* Stores status information for the remote named 'target', which should have
 229  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 230  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 231  * a remote named 'target' or if that remote is an inbound remote that has no
 232  * active connections) returns false.  On failure, 'status' will be zeroed.
 233  */
 234 bool
 235 ovsdb_jsonrpc_server_get_remote_status(
 236     const struct ovsdb_jsonrpc_server *svr, const char *target,
 237     struct ovsdb_jsonrpc_remote_status *status)
 238 {
 239     const struct ovsdb_jsonrpc_remote *remote;
 240
 241     memset(status, 0, sizeof *status);
 242
 243     remote = shash_find_data(&svr->remotes, target);
 244     return remote && ovsdb_jsonrpc_session_get_status(remote, status);
 245 }
 246
 247 void
 248 ovsdb_jsonrpc_server_free_remote_status(
 249     struct ovsdb_jsonrpc_remote_status *status)
 250 {
 251     free(status->locks_held);
 252     free(status->locks_waiting);
 253     free(status->locks_lost);
 254 }
 255
 256 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 257  * reconnect. */
 258 void
 259 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 260 {
 261     struct shash_node *node;
 262
 263     SHASH_FOR_EACH (node, &svr->remotes) {
 264         struct ovsdb_jsonrpc_remote *remote = node->data;
 265
 266         ovsdb_jsonrpc_session_reconnect_all(remote);
 267     }
 268 }
 269
 270 void
 271 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 272 {
 273     struct shash_node *node;
 274
 275     SHASH_FOR_EACH (node, &svr->remotes) {
 276         struct ovsdb_jsonrpc_remote *remote = node->data;
 277
 278         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 279             struct stream *stream;
 280             int error;
 281
 282             error = pstream_accept(remote->listener, &stream);
 283             if (!error) {
 284                 struct jsonrpc_session *js;
 285                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream));
 286                 ovsdb_jsonrpc_session_create(remote, js);
 287             } else if (error != EAGAIN) {
 288                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 289                              pstream_get_name(remote->listener),
 290                              strerror(error));
 291             }
 292         }
 293
 294         ovsdb_jsonrpc_session_run_all(remote);
 295     }
 296 }
 297
 298 void
 299 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 300 {
 301     struct shash_node *node;
 302
 303     SHASH_FOR_EACH (node, &svr->remotes) {
 304         struct ovsdb_jsonrpc_remote *remote = node->data;
 305
 306         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 307             pstream_wait(remote->listener);
 308         }
 309
 310         ovsdb_jsonrpc_session_wait_all(remote);
 311     }
 312 }
 313
 314 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 315  * memory_report(). */
 316 void
 317 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 318                                       struct simap *usage)
 319 {
 320     struct shash_node *node;
 321
 322     simap_increase(usage, "sessions", svr->n_sessions);
 323     SHASH_FOR_EACH (node, &svr->remotes) {
 324         struct ovsdb_jsonrpc_remote *remote = node->data;
 325
 326         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 327     }
 328 }
 329 \f
 330 /* JSON-RPC database server session. */
 331
 332 struct ovsdb_jsonrpc_session {
 333     struct list node;           /* Element in remote's sessions list. */
 334     struct ovsdb_session up;
 335     struct ovsdb_jsonrpc_remote *remote;
 336
 337     /* Triggers. */
 338     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 339
 340     /* Monitors. */
 341     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 342
 343     /* Network connectivity. */
 344     struct jsonrpc_session *js;  /* JSON-RPC session. */
 345     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 346 };
 347
 348 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 349 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 350 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 351 static void ovsdb_jsonrpc_session_get_memory_usage(
 352     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 353 static void ovsdb_jsonrpc_session_set_options(
 354     struct ovsdb_jsonrpc_session *, const struct ovsdb_jsonrpc_options *);
 355 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 356                                              struct jsonrpc_msg *);
 357 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 358                                              struct jsonrpc_msg *);
 359
 360 static struct ovsdb_jsonrpc_session *
 361 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 362                              struct jsonrpc_session *js)
 363 {
 364     struct ovsdb_jsonrpc_session *s;
 365
 366     s = xzalloc(sizeof *s);
 367     ovsdb_session_init(&s->up, &remote->server->up);
 368     s->remote = remote;
 369     list_push_back(&remote->sessions, &s->node);
 370     hmap_init(&s->triggers);
 371     hmap_init(&s->monitors);
 372     s->js = js;
 373     s->js_seqno = jsonrpc_session_get_seqno(js);
 374
 375     remote->server->n_sessions++;
 376
 377     return s;
 378 }
 379
 380 static void
 381 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 382 {
 383     ovsdb_jsonrpc_monitor_remove_all(s);
 384     ovsdb_jsonrpc_session_unlock_all(s);
 385     jsonrpc_session_close(s->js);
 386     list_remove(&s->node);
 387     ovsdb_session_destroy(&s->up);
 388     s->remote->server->n_sessions--;
 389     ovsdb_session_destroy(&s->up);
 390     free(s);
 391 }
 392
 393 static int
 394 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 395 {
 396     jsonrpc_session_run(s->js);
 397     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 398         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 399         ovsdb_jsonrpc_trigger_complete_all(s);
 400         ovsdb_jsonrpc_monitor_remove_all(s);
 401         ovsdb_jsonrpc_session_unlock_all(s);
 402     }
 403
 404     ovsdb_jsonrpc_trigger_complete_done(s);
 405
 406     if (!jsonrpc_session_get_backlog(s->js)) {
 407         struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
 408         if (msg) {
 409             if (msg->type == JSONRPC_REQUEST) {
 410                 ovsdb_jsonrpc_session_got_request(s, msg);
 411             } else if (msg->type == JSONRPC_NOTIFY) {
 412                 ovsdb_jsonrpc_session_got_notify(s, msg);
 413             } else {
 414                 VLOG_WARN("%s: received unexpected %s message",
 415                           jsonrpc_session_get_name(s->js),
 416                           jsonrpc_msg_type_to_string(msg->type));
 417                 jsonrpc_session_force_reconnect(s->js);
 418                 jsonrpc_msg_destroy(msg);
 419             }
 420         }
 421     }
 422     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 423 }
 424
 425 static void
 426 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 427                                   const struct ovsdb_jsonrpc_options *options)
 428 {
 429     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 430     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 431     jsonrpc_session_set_dscp(session->js, options->dscp);
 432 }
 433
 434 static void
 435 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 436 {
 437     struct ovsdb_jsonrpc_session *s, *next;
 438
 439     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 440         int error = ovsdb_jsonrpc_session_run(s);
 441         if (error) {
 442             ovsdb_jsonrpc_session_close(s);
 443         }
 444     }
 445 }
 446
 447 static void
 448 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 449 {
 450     jsonrpc_session_wait(s->js);
 451     if (!jsonrpc_session_get_backlog(s->js)) {
 452         jsonrpc_session_recv_wait(s->js);
 453     }
 454 }
 455
 456 static void
 457 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 458 {
 459     struct ovsdb_jsonrpc_session *s;
 460
 461     LIST_FOR_EACH (s, node, &remote->sessions) {
 462         ovsdb_jsonrpc_session_wait(s);
 463     }
 464 }
 465
 466 static void
 467 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 468                                        struct simap *usage)
 469 {
 470     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 471     simap_increase(usage, "monitors", hmap_count(&s->monitors));
 472     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 473 }
 474
 475 static void
 476 ovsdb_jsonrpc_session_get_memory_usage_all(
 477     const struct ovsdb_jsonrpc_remote *remote,
 478     struct simap *usage)
 479 {
 480     struct ovsdb_jsonrpc_session *s;
 481
 482     LIST_FOR_EACH (s, node, &remote->sessions) {
 483         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 484     }
 485 }
 486
 487 static void
 488 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 489 {
 490     struct ovsdb_jsonrpc_session *s, *next;
 491
 492     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 493         ovsdb_jsonrpc_session_close(s);
 494     }
 495 }
 496
 497 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 498  * reconnect. */
 499 static void
 500 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 501 {
 502     struct ovsdb_jsonrpc_session *s, *next;
 503
 504     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 505         jsonrpc_session_force_reconnect(s->js);
 506         if (!jsonrpc_session_is_alive(s->js)) {
 507             ovsdb_jsonrpc_session_close(s);
 508         }
 509     }
 510 }
 511
 512 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 513  * 'options'. */
 514 static void
 515 ovsdb_jsonrpc_session_set_all_options(
 516     struct ovsdb_jsonrpc_remote *remote,
 517     const struct ovsdb_jsonrpc_options *options)
 518 {
 519     struct ovsdb_jsonrpc_session *s;
 520
 521     LIST_FOR_EACH (s, node, &remote->sessions) {
 522         ovsdb_jsonrpc_session_set_options(s, options);
 523     }
 524 }
 525
 526 static bool
 527 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
 528                                  struct ovsdb_jsonrpc_remote_status *status)
 529 {
 530     const struct ovsdb_jsonrpc_session *s;
 531     const struct jsonrpc_session *js;
 532     struct ovsdb_lock_waiter *waiter;
 533     struct reconnect_stats rstats;
 534     struct ds locks_held, locks_waiting, locks_lost;
 535
 536     if (list_is_empty(&remote->sessions)) {
 537         return false;
 538     }
 539     s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
 540     js = s->js;
 541
 542     status->is_connected = jsonrpc_session_is_connected(js);
 543     status->last_error = jsonrpc_session_get_status(js);
 544
 545     jsonrpc_session_get_reconnect_stats(js, &rstats);
 546     status->state = rstats.state;
 547     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 548         ? UINT_MAX : rstats.msec_since_connect / 1000;
 549     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 550         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 551
 552     ds_init(&locks_held);
 553     ds_init(&locks_waiting);
 554     ds_init(&locks_lost);
 555     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 556         struct ds *string;
 557
 558         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 559                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 560                   : &locks_lost);
 561         if (string->length) {
 562             ds_put_char(string, ' ');
 563         }
 564         ds_put_cstr(string, waiter->lock_name);
 565     }
 566     status->locks_held = ds_steal_cstr(&locks_held);
 567     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 568     status->locks_lost = ds_steal_cstr(&locks_lost);
 569
 570     status->n_connections = list_size(&remote->sessions);
 571
 572     return true;
 573 }
 574
 575 /* Examines 'request' to determine the database to which it relates, and then
 576  * searches 's' to find that database:
 577  *
 578  *    - If successful, returns the database and sets '*replyp' to NULL.
 579  *
 580  *    - If no such database exists, returns NULL and sets '*replyp' to an
 581  *      appropriate JSON-RPC error reply, owned by the caller. */
 582 static struct ovsdb *
 583 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 584                         const struct jsonrpc_msg *request,
 585                         struct jsonrpc_msg **replyp)
 586 {
 587     struct json_array *params;
 588     struct ovsdb_error *error;
 589     const char *db_name;
 590     struct ovsdb *db;
 591
 592     params = json_array(request->params);
 593     if (!params->n || params->elems[0]->type != JSON_STRING) {
 594         error = ovsdb_syntax_error(
 595             request->params, NULL,
 596             "%s request params must begin with <db-name>", request->method);
 597         goto error;
 598     }
 599
 600     db_name = params->elems[0]->u.string;
 601     db = shash_find_data(&s->up.server->dbs, db_name);
 602     if (!db) {
 603         error = ovsdb_syntax_error(
 604             request->params, "unknown database",
 605             "%s request specifies unknown database %s",
 606             request->method, db_name);
 607         goto error;
 608     }
 609
 610     *replyp = NULL;
 611     return db;
 612
 613 error:
 614     *replyp = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 615     ovsdb_error_destroy(error);
 616     return NULL;
 617 }
 618
 619 static struct ovsdb_error *
 620 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 621                                       const char **lock_namep)
 622 {
 623     const struct json_array *params;
 624
 625     params = json_array(request->params);
 626     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 627         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 628         *lock_namep = NULL;
 629         return ovsdb_syntax_error(request->params, NULL,
 630                                   "%s request params must be <id>",
 631                                   request->method);
 632     }
 633
 634     *lock_namep = json_string(params->elems[0]);
 635     return NULL;
 636 }
 637
 638 static void
 639 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 640                              const char *lock_name,
 641                              const char *method)
 642 {
 643     struct ovsdb_jsonrpc_session *s;
 644     struct json *params;
 645
 646     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 647     params = json_array_create_1(json_string_create(lock_name));
 648     jsonrpc_session_send(s->js, jsonrpc_create_notify(method, params));
 649 }
 650
 651 static struct jsonrpc_msg *
 652 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 653                            struct jsonrpc_msg *request,
 654                            enum ovsdb_lock_mode mode)
 655 {
 656     struct ovsdb_lock_waiter *waiter;
 657     struct jsonrpc_msg *reply;
 658     struct ovsdb_error *error;
 659     struct ovsdb_session *victim;
 660     const char *lock_name;
 661     struct json *result;
 662
 663     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 664     if (error) {
 665         goto error;
 666     }
 667
 668     /* Report error if this session has issued a "lock" or "steal" without a
 669      * matching "unlock" for this lock. */
 670     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 671     if (waiter) {
 672         error = ovsdb_syntax_error(
 673             request->params, NULL,
 674             "must issue \"unlock\" before new \"%s\"", request->method);
 675         goto error;
 676     }
 677
 678     /* Get the lock, add us as a waiter. */
 679     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 680                                &victim);
 681     if (victim) {
 682         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 683     }
 684
 685     result = json_object_create();
 686     json_object_put(result, "locked",
 687                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 688
 689     return jsonrpc_create_reply(result, request->id);
 690
 691 error:
 692     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 693     ovsdb_error_destroy(error);
 694     return reply;
 695 }
 696
 697 static void
 698 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 699 {
 700     struct ovsdb_lock_waiter *waiter, *next;
 701
 702     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 703         ovsdb_jsonrpc_session_unlock__(waiter);
 704     }
 705 }
 706
 707 static void
 708 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 709 {
 710     struct ovsdb_lock *lock = waiter->lock;
 711
 712     if (lock) {
 713         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 714         if (new_owner) {
 715             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 716         } else {
 717             /* ovsdb_server_lock() might have freed 'lock'. */
 718         }
 719     }
 720
 721     ovsdb_lock_waiter_destroy(waiter);
 722 }
 723
 724 static struct jsonrpc_msg *
 725 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 726                              struct jsonrpc_msg *request)
 727 {
 728     struct ovsdb_lock_waiter *waiter;
 729     struct jsonrpc_msg *reply;
 730     struct ovsdb_error *error;
 731     const char *lock_name;
 732
 733     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 734     if (error) {
 735         goto error;
 736     }
 737
 738     /* Report error if this session has not issued a "lock" or "steal" for this
 739      * lock. */
 740     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 741     if (!waiter) {
 742         error = ovsdb_syntax_error(
 743             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 744         goto error;
 745     }
 746
 747     ovsdb_jsonrpc_session_unlock__(waiter);
 748
 749     return jsonrpc_create_reply(json_object_create(), request->id);
 750
 751 error:
 752     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 753     ovsdb_error_destroy(error);
 754     return reply;
 755 }
 756
 757 static struct jsonrpc_msg *
 758 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 759                     struct jsonrpc_msg *request)
 760 {
 761     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 762     request->id = NULL;
 763     request->params = NULL;
 764     jsonrpc_msg_destroy(request);
 765     return NULL;
 766 }
 767
 768 static void
 769 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 770                                   struct jsonrpc_msg *request)
 771 {
 772     struct jsonrpc_msg *reply;
 773
 774     if (!strcmp(request->method, "transact")) {
 775         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 776         if (!reply) {
 777             reply = execute_transaction(s, db, request);
 778         }
 779     } else if (!strcmp(request->method, "monitor")) {
 780         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 781         if (!reply) {
 782             reply = jsonrpc_create_reply(
 783                 ovsdb_jsonrpc_monitor_create(s, db, request->params),
 784                 request->id);
 785         }
 786     } else if (!strcmp(request->method, "monitor_cancel")) {
 787         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 788                                              request->id);
 789     } else if (!strcmp(request->method, "get_schema")) {
 790         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 791         if (!reply) {
 792             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 793                                          request->id);
 794         }
 795     } else if (!strcmp(request->method, "list_dbs")) {
 796         size_t n_dbs = shash_count(&s->up.server->dbs);
 797         struct shash_node *node;
 798         struct json **dbs;
 799         size_t i;
 800
 801         dbs = xmalloc(n_dbs * sizeof *dbs);
 802         i = 0;
 803         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 804             dbs[i++] = json_string_create(node->name);
 805         }
 806         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 807                                      request->id);
 808     } else if (!strcmp(request->method, "lock")) {
 809         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 810     } else if (!strcmp(request->method, "steal")) {
 811         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 812     } else if (!strcmp(request->method, "unlock")) {
 813         reply = ovsdb_jsonrpc_session_unlock(s, request);
 814     } else if (!strcmp(request->method, "echo")) {
 815         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 816     } else {
 817         reply = jsonrpc_create_error(json_string_create("unknown method"),
 818                                      request->id);
 819     }
 820
 821     if (reply) {
 822         jsonrpc_msg_destroy(request);
 823         jsonrpc_session_send(s->js, reply);
 824     }
 825 }
 826
 827 static void
 828 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 829 {
 830     if (json_array(request->params)->n == 1) {
 831         struct ovsdb_jsonrpc_trigger *t;
 832         struct json *id;
 833
 834         id = request->params->u.array.elems[0];
 835         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 836         if (t) {
 837             ovsdb_jsonrpc_trigger_complete(t);
 838         }
 839     }
 840 }
 841
 842 static void
 843 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 844                                  struct jsonrpc_msg *request)
 845 {
 846     if (!strcmp(request->method, "cancel")) {
 847         execute_cancel(s, request);
 848     }
 849     jsonrpc_msg_destroy(request);
 850 }
 851 \f
 852 /* JSON-RPC database server triggers.
 853  *
 854  * (Every transaction is treated as a trigger even if it doesn't actually have
 855  * any "wait" operations.) */
 856
 857 struct ovsdb_jsonrpc_trigger {
 858     struct ovsdb_trigger trigger;
 859     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 860     struct json *id;
 861 };
 862
 863 static void
 864 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 865                              struct json *id, struct json *params)
 866 {
 867     struct ovsdb_jsonrpc_trigger *t;
 868     size_t hash;
 869
 870     /* Check for duplicate ID. */
 871     hash = json_hash(id, 0);
 872     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 873     if (t) {
 874         struct jsonrpc_msg *msg;
 875
 876         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 877                                    id);
 878         jsonrpc_session_send(s->js, msg);
 879         json_destroy(id);
 880         json_destroy(params);
 881         return;
 882     }
 883
 884     /* Insert into trigger table. */
 885     t = xmalloc(sizeof *t);
 886     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 887     t->id = id;
 888     hmap_insert(&s->triggers, &t->hmap_node, hash);
 889
 890     /* Complete early if possible. */
 891     if (ovsdb_trigger_is_complete(&t->trigger)) {
 892         ovsdb_jsonrpc_trigger_complete(t);
 893     }
 894 }
 895
 896 static struct ovsdb_jsonrpc_trigger *
 897 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 898                            const struct json *id, size_t hash)
 899 {
 900     struct ovsdb_jsonrpc_trigger *t;
 901
 902     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
 903         if (json_equal(t->id, id)) {
 904             return t;
 905         }
 906     }
 907
 908     return NULL;
 909 }
 910
 911 static void
 912 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 913 {
 914     struct ovsdb_jsonrpc_session *s;
 915
 916     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 917
 918     if (jsonrpc_session_is_connected(s->js)) {
 919         struct jsonrpc_msg *reply;
 920         struct json *result;
 921
 922         result = ovsdb_trigger_steal_result(&t->trigger);
 923         if (result) {
 924             reply = jsonrpc_create_reply(result, t->id);
 925         } else {
 926             reply = jsonrpc_create_error(json_string_create("canceled"),
 927                                          t->id);
 928         }
 929         jsonrpc_session_send(s->js, reply);
 930     }
 931
 932     json_destroy(t->id);
 933     ovsdb_trigger_destroy(&t->trigger);
 934     hmap_remove(&s->triggers, &t->hmap_node);
 935     free(t);
 936 }
 937
 938 static void
 939 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
 940 {
 941     struct ovsdb_jsonrpc_trigger *t, *next;
 942     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
 943         ovsdb_jsonrpc_trigger_complete(t);
 944     }
 945 }
 946
 947 static void
 948 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
 949 {
 950     while (!list_is_empty(&s->up.completions)) {
 951         struct ovsdb_jsonrpc_trigger *t
 952             = CONTAINER_OF(s->up.completions.next,
 953                            struct ovsdb_jsonrpc_trigger, trigger.node);
 954         ovsdb_jsonrpc_trigger_complete(t);
 955     }
 956 }
 957 \f
 958 /* JSON-RPC database table monitors. */
 959
 960 enum ovsdb_jsonrpc_monitor_selection {
 961     OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
 962     OJMS_INSERT = 1 << 1,       /* New rows. */
 963     OJMS_DELETE = 1 << 2,       /* Deleted rows. */
 964     OJMS_MODIFY = 1 << 3        /* Modified rows. */
 965 };
 966
 967 /* A particular column being monitored. */
 968 struct ovsdb_jsonrpc_monitor_column {
 969     const struct ovsdb_column *column;
 970     enum ovsdb_jsonrpc_monitor_selection select;
 971 };
 972
 973 /* A particular table being monitored. */
 974 struct ovsdb_jsonrpc_monitor_table {
 975     const struct ovsdb_table *table;
 976
 977     /* This is the union (bitwise-OR) of the 'select' values in all of the
 978      * members of 'columns' below. */
 979     enum ovsdb_jsonrpc_monitor_selection select;
 980
 981     /* Columns being monitored. */
 982     struct ovsdb_jsonrpc_monitor_column *columns;
 983     size_t n_columns;
 984 };
 985
 986 /* A collection of tables being monitored. */
 987 struct ovsdb_jsonrpc_monitor {
 988     struct ovsdb_replica replica;
 989     struct ovsdb_jsonrpc_session *session;
 990     struct ovsdb *db;
 991     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
 992
 993     struct json *monitor_id;
 994     struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
 995 };
 996
 997 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
 998
 999 struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
1000     struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
1001 static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
1002 static struct json *ovsdb_jsonrpc_monitor_get_initial(
1003     const struct ovsdb_jsonrpc_monitor *);
1004
1005 static bool
1006 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1007 {
1008     const struct json *json;
1009
1010     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1011     return json ? json_boolean(json) : default_value;
1012 }
1013
1014 struct ovsdb_jsonrpc_monitor *
1015 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1016                            const struct json *monitor_id)
1017 {
1018     struct ovsdb_jsonrpc_monitor *m;
1019
1020     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1021         if (json_equal(m->monitor_id, monitor_id)) {
1022             return m;
1023         }
1024     }
1025
1026     return NULL;
1027 }
1028
1029 static void
1030 ovsdb_jsonrpc_add_monitor_column(struct ovsdb_jsonrpc_monitor_table *mt,
1031                                  const struct ovsdb_column *column,
1032                                  enum ovsdb_jsonrpc_monitor_selection select,
1033                                  size_t *allocated_columns)
1034 {
1035     struct ovsdb_jsonrpc_monitor_column *c;
1036
1037     if (mt->n_columns >= *allocated_columns) {
1038         mt->columns = x2nrealloc(mt->columns, allocated_columns,
1039                                  sizeof *mt->columns);
1040     }
1041
1042     c = &mt->columns[mt->n_columns++];
1043     c->column = column;
1044     c->select = select;
1045 }
1046
1047 static int
1048 compare_ovsdb_jsonrpc_monitor_column(const void *a_, const void *b_)
1049 {
1050     const struct ovsdb_jsonrpc_monitor_column *a = a_;
1051     const struct ovsdb_jsonrpc_monitor_column *b = b_;
1052
1053     return a->column < b->column ? -1 : a->column > b->column;
1054 }
1055
1056 static struct ovsdb_error * WARN_UNUSED_RESULT
1057 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
1058                                     const struct json *monitor_request,
1059                                     size_t *allocated_columns)
1060 {
1061     const struct ovsdb_table_schema *ts = mt->table->schema;
1062     enum ovsdb_jsonrpc_monitor_selection select;
1063     const struct json *columns, *select_json;
1064     struct ovsdb_parser parser;
1065     struct ovsdb_error *error;
1066
1067     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1068     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1069     select_json = ovsdb_parser_member(&parser, "select",
1070                                       OP_OBJECT | OP_OPTIONAL);
1071     error = ovsdb_parser_finish(&parser);
1072     if (error) {
1073         return error;
1074     }
1075
1076     if (select_json) {
1077         select = 0;
1078         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1079         if (parse_bool(&parser, "initial", true)) {
1080             select |= OJMS_INITIAL;
1081         }
1082         if (parse_bool(&parser, "insert", true)) {
1083             select |= OJMS_INSERT;
1084         }
1085         if (parse_bool(&parser, "delete", true)) {
1086             select |= OJMS_DELETE;
1087         }
1088         if (parse_bool(&parser, "modify", true)) {
1089             select |= OJMS_MODIFY;
1090         }
1091         error = ovsdb_parser_finish(&parser);
1092         if (error) {
1093             return error;
1094         }
1095     } else {
1096         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1097     }
1098     mt->select |= select;
1099
1100     if (columns) {
1101         size_t i;
1102
1103         if (columns->type != JSON_ARRAY) {
1104             return ovsdb_syntax_error(columns, NULL,
1105                                       "array of column names expected");
1106         }
1107
1108         for (i = 0; i < columns->u.array.n; i++) {
1109             const struct ovsdb_column *column;
1110             const char *s;
1111
1112             if (columns->u.array.elems[i]->type != JSON_STRING) {
1113                 return ovsdb_syntax_error(columns, NULL,
1114                                           "array of column names expected");
1115             }
1116
1117             s = columns->u.array.elems[i]->u.string;
1118             column = shash_find_data(&mt->table->schema->columns, s);
1119             if (!column) {
1120                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1121                                           "column name", s);
1122             }
1123             ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1124                                              allocated_columns);
1125         }
1126     } else {
1127         struct shash_node *node;
1128
1129         SHASH_FOR_EACH (node, &ts->columns) {
1130             const struct ovsdb_column *column = node->data;
1131             if (column->index != OVSDB_COL_UUID) {
1132                 ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1133                                                  allocated_columns);
1134             }
1135         }
1136     }
1137
1138     return NULL;
1139 }
1140
1141 static struct json *
1142 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1143                              struct json *params)
1144 {
1145     struct ovsdb_jsonrpc_monitor *m = NULL;
1146     struct json *monitor_id, *monitor_requests;
1147     struct ovsdb_error *error = NULL;
1148     struct shash_node *node;
1149     struct json *json;
1150
1151     if (json_array(params)->n != 3) {
1152         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1153         goto error;
1154     }
1155     monitor_id = params->u.array.elems[1];
1156     monitor_requests = params->u.array.elems[2];
1157     if (monitor_requests->type != JSON_OBJECT) {
1158         error = ovsdb_syntax_error(monitor_requests, NULL,
1159                                    "monitor-requests must be object");
1160         goto error;
1161     }
1162
1163     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1164         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1165         goto error;
1166     }
1167
1168     m = xzalloc(sizeof *m);
1169     ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
1170     ovsdb_add_replica(db, &m->replica);
1171     m->session = s;
1172     m->db = db;
1173     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1174     m->monitor_id = json_clone(monitor_id);
1175     shash_init(&m->tables);
1176
1177     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1178         const struct ovsdb_table *table;
1179         struct ovsdb_jsonrpc_monitor_table *mt;
1180         size_t allocated_columns;
1181         const struct json *mr_value;
1182         size_t i;
1183
1184         table = ovsdb_get_table(m->db, node->name);
1185         if (!table) {
1186             error = ovsdb_syntax_error(NULL, NULL,
1187                                        "no table named %s", node->name);
1188             goto error;
1189         }
1190
1191         mt = xzalloc(sizeof *mt);
1192         mt->table = table;
1193         shash_add(&m->tables, table->schema->name, mt);
1194
1195         /* Parse columns. */
1196         mr_value = node->data;
1197         allocated_columns = 0;
1198         if (mr_value->type == JSON_ARRAY) {
1199             const struct json_array *array = &mr_value->u.array;
1200
1201             for (i = 0; i < array->n; i++) {
1202                 error = ovsdb_jsonrpc_parse_monitor_request(
1203                     mt, array->elems[i], &allocated_columns);
1204                 if (error) {
1205                     goto error;
1206                 }
1207             }
1208         } else {
1209             error = ovsdb_jsonrpc_parse_monitor_request(
1210                 mt, mr_value, &allocated_columns);
1211             if (error) {
1212                 goto error;
1213             }
1214         }
1215
1216         /* Check for duplicate columns. */
1217         qsort(mt->columns, mt->n_columns, sizeof *mt->columns,
1218               compare_ovsdb_jsonrpc_monitor_column);
1219         for (i = 1; i < mt->n_columns; i++) {
1220             if (mt->columns[i].column == mt->columns[i - 1].column) {
1221                 error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1222                                            "mentioned more than once",
1223                                            mt->columns[i].column->name);
1224                 goto error;
1225             }
1226         }
1227     }
1228
1229     return ovsdb_jsonrpc_monitor_get_initial(m);
1230
1231 error:
1232     if (m) {
1233         ovsdb_remove_replica(m->db, &m->replica);
1234     }
1235
1236     json = ovsdb_error_to_json(error);
1237     ovsdb_error_destroy(error);
1238     return json;
1239 }
1240
1241 static struct jsonrpc_msg *
1242 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1243                              struct json_array *params,
1244                              const struct json *request_id)
1245 {
1246     if (params->n != 1) {
1247         return jsonrpc_create_error(json_string_create("invalid parameters"),
1248                                     request_id);
1249     } else {
1250         struct ovsdb_jsonrpc_monitor *m;
1251
1252         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1253         if (!m) {
1254             return jsonrpc_create_error(json_string_create("unknown monitor"),
1255                                         request_id);
1256         } else {
1257             ovsdb_remove_replica(m->db, &m->replica);
1258             return jsonrpc_create_reply(json_object_create(), request_id);
1259         }
1260     }
1261 }
1262
1263 static void
1264 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1265 {
1266     struct ovsdb_jsonrpc_monitor *m, *next;
1267
1268     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1269         ovsdb_remove_replica(m->db, &m->replica);
1270     }
1271 }
1272
1273 static struct ovsdb_jsonrpc_monitor *
1274 ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
1275 {
1276     assert(replica->class == &ovsdb_jsonrpc_replica_class);
1277     return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
1278 }
1279
1280 struct ovsdb_jsonrpc_monitor_aux {
1281     bool initial;               /* Sending initial contents of table? */
1282     const struct ovsdb_jsonrpc_monitor *monitor;
1283     struct json *json;          /* JSON for the whole transaction. */
1284
1285     /* Current table.  */
1286     struct ovsdb_jsonrpc_monitor_table *mt;
1287     struct json *table_json;    /* JSON for table's transaction. */
1288 };
1289
1290 static bool
1291 any_reportable_change(const struct ovsdb_jsonrpc_monitor_table *mt,
1292                       const unsigned long int *changed)
1293 {
1294     size_t i;
1295
1296     for (i = 0; i < mt->n_columns; i++) {
1297         const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1298         unsigned int idx = c->column->index;
1299
1300         if (c->select & OJMS_MODIFY && bitmap_is_set(changed, idx)) {
1301             return true;
1302         }
1303     }
1304
1305     return false;
1306 }
1307
1308 static bool
1309 ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
1310                                 const struct ovsdb_row *new,
1311                                 const unsigned long int *changed,
1312                                 void *aux_)
1313 {
1314     struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
1315     const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
1316     struct ovsdb_table *table = new ? new->table : old->table;
1317     enum ovsdb_jsonrpc_monitor_selection type;
1318     struct json *old_json, *new_json;
1319     struct json *row_json;
1320     char uuid[UUID_LEN + 1];
1321     size_t i;
1322
1323     if (!aux->mt || table != aux->mt->table) {
1324         aux->mt = shash_find_data(&m->tables, table->schema->name);
1325         aux->table_json = NULL;
1326         if (!aux->mt) {
1327             /* We don't care about rows in this table at all.  Tell the caller
1328              * to skip it.  */
1329             return false;
1330         }
1331     }
1332
1333     type = (aux->initial ? OJMS_INITIAL
1334             : !old ? OJMS_INSERT
1335             : !new ? OJMS_DELETE
1336             : OJMS_MODIFY);
1337     if (!(aux->mt->select & type)) {
1338         /* We don't care about this type of change (but do want to be called
1339          * back for changes to other rows in the same table). */
1340         return true;
1341     }
1342
1343     if (type == OJMS_MODIFY && !any_reportable_change(aux->mt, changed)) {
1344         /* Nothing of interest changed. */
1345         return true;
1346     }
1347
1348     old_json = new_json = NULL;
1349     if (type & (OJMS_DELETE | OJMS_MODIFY)) {
1350         old_json = json_object_create();
1351     }
1352     if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1353         new_json = json_object_create();
1354     }
1355     for (i = 0; i < aux->mt->n_columns; i++) {
1356         const struct ovsdb_jsonrpc_monitor_column *c = &aux->mt->columns[i];
1357         const struct ovsdb_column *column = c->column;
1358         unsigned int idx = c->column->index;
1359
1360         if (!(type & c->select)) {
1361             /* We don't care about this type of change for this particular
1362              * column (but we will care about it for some other column). */
1363             continue;
1364         }
1365
1366         if ((type == OJMS_MODIFY && bitmap_is_set(changed, idx))
1367             || type == OJMS_DELETE) {
1368             json_object_put(old_json, column->name,
1369                             ovsdb_datum_to_json(&old->fields[idx],
1370                                                 &column->type));
1371         }
1372         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1373             json_object_put(new_json, column->name,
1374                             ovsdb_datum_to_json(&new->fields[idx],
1375                                                 &column->type));
1376         }
1377     }
1378
1379     /* Create JSON object for transaction overall. */
1380     if (!aux->json) {
1381         aux->json = json_object_create();
1382     }
1383
1384     /* Create JSON object for transaction on this table. */
1385     if (!aux->table_json) {
1386         aux->table_json = json_object_create();
1387         json_object_put(aux->json, aux->mt->table->schema->name,
1388                         aux->table_json);
1389     }
1390
1391     /* Create JSON object for transaction on this row. */
1392     row_json = json_object_create();
1393     if (old_json) {
1394         json_object_put(row_json, "old", old_json);
1395     }
1396     if (new_json) {
1397         json_object_put(row_json, "new", new_json);
1398     }
1399
1400     /* Add JSON row to JSON table. */
1401     snprintf(uuid, sizeof uuid,
1402              UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
1403     json_object_put(aux->table_json, uuid, row_json);
1404
1405     return true;
1406 }
1407
1408 static void
1409 ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
1410                                const struct ovsdb_jsonrpc_monitor *m,
1411                                bool initial)
1412 {
1413     aux->initial = initial;
1414     aux->monitor = m;
1415     aux->json = NULL;
1416     aux->mt = NULL;
1417     aux->table_json = NULL;
1418 }
1419
1420 static struct ovsdb_error *
1421 ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
1422                              const struct ovsdb_txn *txn,
1423                              bool durable OVS_UNUSED)
1424 {
1425     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1426     struct ovsdb_jsonrpc_monitor_aux aux;
1427
1428     ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
1429     ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
1430     if (aux.json) {
1431         struct jsonrpc_msg *msg;
1432         struct json *params;
1433
1434         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
1435                                      aux.json);
1436         msg = jsonrpc_create_notify("update", params);
1437         jsonrpc_session_send(aux.monitor->session->js, msg);
1438     }
1439
1440     return NULL;
1441 }
1442
1443 static struct json *
1444 ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
1445 {
1446     struct ovsdb_jsonrpc_monitor_aux aux;
1447     struct shash_node *node;
1448
1449     ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
1450     SHASH_FOR_EACH (node, &m->tables) {
1451         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1452
1453         if (mt->select & OJMS_INITIAL) {
1454             struct ovsdb_row *row;
1455
1456             HMAP_FOR_EACH (row, hmap_node, &mt->table->rows) {
1457                 ovsdb_jsonrpc_monitor_change_cb(NULL, row, NULL, &aux);
1458             }
1459         }
1460     }
1461     return aux.json ? aux.json : json_object_create();
1462 }
1463
1464 static void
1465 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
1466 {
1467     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1468     struct shash_node *node;
1469
1470     json_destroy(m->monitor_id);
1471     SHASH_FOR_EACH (node, &m->tables) {
1472         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1473         free(mt->columns);
1474         free(mt);
1475     }
1476     shash_destroy(&m->tables);
1477     hmap_remove(&m->session->monitors, &m->node);
1478     free(m);
1479 }
1480
1481 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
1482     ovsdb_jsonrpc_monitor_commit,
1483     ovsdb_jsonrpc_monitor_destroy
1484 };