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     uint8_t dscp;
 103 };
 104
 105 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 106     struct ovsdb_jsonrpc_server *, const char *name,
 107     const struct ovsdb_jsonrpc_options *options
 108 );
 109 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 110
 111 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 112  *
 113  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 114  * which 'server' should provide access. */
 115 struct ovsdb_jsonrpc_server *
 116 ovsdb_jsonrpc_server_create(void)
 117 {
 118     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 119     ovsdb_server_init(&server->up);
 120     server->max_sessions = 64;
 121     shash_init(&server->remotes);
 122     return server;
 123 }
 124
 125 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 126  * successful, false if 'db''s name is the same as some database already in
 127  * 'server'. */
 128 bool
 129 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 130 {
 131     return ovsdb_server_add_db(&svr->up, db);
 132 }
 133
 134 void
 135 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 136 {
 137     struct shash_node *node, *next;
 138
 139     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 140         ovsdb_jsonrpc_server_del_remote(node);
 141     }
 142     shash_destroy(&svr->remotes);
 143     ovsdb_server_destroy(&svr->up);
 144     free(svr);
 145 }
 146
 147 struct ovsdb_jsonrpc_options *
 148 ovsdb_jsonrpc_default_options(const char *target)
 149 {
 150     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 151     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 152     options->probe_interval = (stream_or_pstream_needs_probes(target)
 153                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 154                                : 0);
 155     return options;
 156 }
 157
 158 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 159  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 160  *
 161  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 162  * "tcp:1.2.3.4". */
 163 void
 164 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 165                                  const struct shash *new_remotes)
 166 {
 167     struct shash_node *node, *next;
 168
 169     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 170         if (!shash_find(new_remotes, node->name)) {
 171             VLOG_INFO("%s: remote deconfigured", node->name);
 172             ovsdb_jsonrpc_server_del_remote(node);
 173         }
 174     }
 175     SHASH_FOR_EACH (node, new_remotes) {
 176         const struct ovsdb_jsonrpc_options *options = node->data;
 177         struct ovsdb_jsonrpc_remote *remote;
 178
 179         remote = shash_find_data(&svr->remotes, node->name);
 180         if (!remote) {
 181             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 182             if (!remote) {
 183                 continue;
 184             }
 185         }
 186
 187         ovsdb_jsonrpc_session_set_all_options(remote, options);
 188     }
 189 }
 190
 191 static struct ovsdb_jsonrpc_remote *
 192 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 193                                 const char *name,
 194                                 const struct ovsdb_jsonrpc_options *options)
 195 {
 196     struct ovsdb_jsonrpc_remote *remote;
 197     struct pstream *listener;
 198     int error;
 199
 200     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 201     if (error && error != EAFNOSUPPORT) {
 202         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, strerror(error));
 203         return NULL;
 204     }
 205
 206     remote = xmalloc(sizeof *remote);
 207     remote->server = svr;
 208     remote->listener = listener;
 209     list_init(&remote->sessions);
 210     remote->dscp = options->dscp;
 211     shash_add(&svr->remotes, name, remote);
 212
 213     if (!listener) {
 214         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name));
 215     }
 216     return remote;
 217 }
 218
 219 static void
 220 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 221 {
 222     struct ovsdb_jsonrpc_remote *remote = node->data;
 223
 224     ovsdb_jsonrpc_session_close_all(remote);
 225     pstream_close(remote->listener);
 226     shash_delete(&remote->server->remotes, node);
 227     free(remote);
 228 }
 229
 230 /* Stores status information for the remote named 'target', which should have
 231  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 232  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 233  * a remote named 'target' or if that remote is an inbound remote that has no
 234  * active connections) returns false.  On failure, 'status' will be zeroed.
 235  */
 236 bool
 237 ovsdb_jsonrpc_server_get_remote_status(
 238     const struct ovsdb_jsonrpc_server *svr, const char *target,
 239     struct ovsdb_jsonrpc_remote_status *status)
 240 {
 241     const struct ovsdb_jsonrpc_remote *remote;
 242
 243     memset(status, 0, sizeof *status);
 244
 245     remote = shash_find_data(&svr->remotes, target);
 246     return remote && ovsdb_jsonrpc_session_get_status(remote, status);
 247 }
 248
 249 void
 250 ovsdb_jsonrpc_server_free_remote_status(
 251     struct ovsdb_jsonrpc_remote_status *status)
 252 {
 253     free(status->locks_held);
 254     free(status->locks_waiting);
 255     free(status->locks_lost);
 256 }
 257
 258 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 259  * reconnect. */
 260 void
 261 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 262 {
 263     struct shash_node *node;
 264
 265     SHASH_FOR_EACH (node, &svr->remotes) {
 266         struct ovsdb_jsonrpc_remote *remote = node->data;
 267
 268         ovsdb_jsonrpc_session_reconnect_all(remote);
 269     }
 270 }
 271
 272 void
 273 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 274 {
 275     struct shash_node *node;
 276
 277     SHASH_FOR_EACH (node, &svr->remotes) {
 278         struct ovsdb_jsonrpc_remote *remote = node->data;
 279
 280         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 281             struct stream *stream;
 282             int error;
 283
 284             error = pstream_accept(remote->listener, &stream);
 285             if (!error) {
 286                 struct jsonrpc_session *js;
 287                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
 288                                                      remote->dscp);
 289                 ovsdb_jsonrpc_session_create(remote, js);
 290             } else if (error != EAGAIN) {
 291                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 292                              pstream_get_name(remote->listener),
 293                              strerror(error));
 294             }
 295         }
 296
 297         ovsdb_jsonrpc_session_run_all(remote);
 298     }
 299 }
 300
 301 void
 302 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 303 {
 304     struct shash_node *node;
 305
 306     SHASH_FOR_EACH (node, &svr->remotes) {
 307         struct ovsdb_jsonrpc_remote *remote = node->data;
 308
 309         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 310             pstream_wait(remote->listener);
 311         }
 312
 313         ovsdb_jsonrpc_session_wait_all(remote);
 314     }
 315 }
 316
 317 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 318  * memory_report(). */
 319 void
 320 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 321                                       struct simap *usage)
 322 {
 323     struct shash_node *node;
 324
 325     simap_increase(usage, "sessions", svr->n_sessions);
 326     SHASH_FOR_EACH (node, &svr->remotes) {
 327         struct ovsdb_jsonrpc_remote *remote = node->data;
 328
 329         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 330     }
 331 }
 332 \f
 333 /* JSON-RPC database server session. */
 334
 335 struct ovsdb_jsonrpc_session {
 336     struct list node;           /* Element in remote's sessions list. */
 337     struct ovsdb_session up;
 338     struct ovsdb_jsonrpc_remote *remote;
 339
 340     /* Triggers. */
 341     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 342
 343     /* Monitors. */
 344     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 345
 346     /* Network connectivity. */
 347     struct jsonrpc_session *js;  /* JSON-RPC session. */
 348     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 349 };
 350
 351 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 352 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 353 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 354 static void ovsdb_jsonrpc_session_get_memory_usage(
 355     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 356 static void ovsdb_jsonrpc_session_set_options(
 357     struct ovsdb_jsonrpc_session *, const struct ovsdb_jsonrpc_options *);
 358 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 359                                              struct jsonrpc_msg *);
 360 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 361                                              struct jsonrpc_msg *);
 362
 363 static struct ovsdb_jsonrpc_session *
 364 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 365                              struct jsonrpc_session *js)
 366 {
 367     struct ovsdb_jsonrpc_session *s;
 368
 369     s = xzalloc(sizeof *s);
 370     ovsdb_session_init(&s->up, &remote->server->up);
 371     s->remote = remote;
 372     list_push_back(&remote->sessions, &s->node);
 373     hmap_init(&s->triggers);
 374     hmap_init(&s->monitors);
 375     s->js = js;
 376     s->js_seqno = jsonrpc_session_get_seqno(js);
 377
 378     remote->server->n_sessions++;
 379
 380     return s;
 381 }
 382
 383 static void
 384 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 385 {
 386     ovsdb_jsonrpc_monitor_remove_all(s);
 387     ovsdb_jsonrpc_session_unlock_all(s);
 388     jsonrpc_session_close(s->js);
 389     list_remove(&s->node);
 390     ovsdb_session_destroy(&s->up);
 391     s->remote->server->n_sessions--;
 392     ovsdb_session_destroy(&s->up);
 393     free(s);
 394 }
 395
 396 static int
 397 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 398 {
 399     jsonrpc_session_run(s->js);
 400     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 401         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 402         ovsdb_jsonrpc_trigger_complete_all(s);
 403         ovsdb_jsonrpc_monitor_remove_all(s);
 404         ovsdb_jsonrpc_session_unlock_all(s);
 405     }
 406
 407     ovsdb_jsonrpc_trigger_complete_done(s);
 408
 409     if (!jsonrpc_session_get_backlog(s->js)) {
 410         struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
 411         if (msg) {
 412             if (msg->type == JSONRPC_REQUEST) {
 413                 ovsdb_jsonrpc_session_got_request(s, msg);
 414             } else if (msg->type == JSONRPC_NOTIFY) {
 415                 ovsdb_jsonrpc_session_got_notify(s, msg);
 416             } else {
 417                 VLOG_WARN("%s: received unexpected %s message",
 418                           jsonrpc_session_get_name(s->js),
 419                           jsonrpc_msg_type_to_string(msg->type));
 420                 jsonrpc_session_force_reconnect(s->js);
 421                 jsonrpc_msg_destroy(msg);
 422             }
 423         }
 424     }
 425     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 426 }
 427
 428 static void
 429 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 430                                   const struct ovsdb_jsonrpc_options *options)
 431 {
 432     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 433     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 434     jsonrpc_session_set_dscp(session->js, options->dscp);
 435 }
 436
 437 static void
 438 ovsdb_jsonrpc_session_run_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         int error = ovsdb_jsonrpc_session_run(s);
 444         if (error) {
 445             ovsdb_jsonrpc_session_close(s);
 446         }
 447     }
 448 }
 449
 450 static void
 451 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 452 {
 453     jsonrpc_session_wait(s->js);
 454     if (!jsonrpc_session_get_backlog(s->js)) {
 455         jsonrpc_session_recv_wait(s->js);
 456     }
 457 }
 458
 459 static void
 460 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 461 {
 462     struct ovsdb_jsonrpc_session *s;
 463
 464     LIST_FOR_EACH (s, node, &remote->sessions) {
 465         ovsdb_jsonrpc_session_wait(s);
 466     }
 467 }
 468
 469 static void
 470 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 471                                        struct simap *usage)
 472 {
 473     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 474     simap_increase(usage, "monitors", hmap_count(&s->monitors));
 475     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 476 }
 477
 478 static void
 479 ovsdb_jsonrpc_session_get_memory_usage_all(
 480     const struct ovsdb_jsonrpc_remote *remote,
 481     struct simap *usage)
 482 {
 483     struct ovsdb_jsonrpc_session *s;
 484
 485     LIST_FOR_EACH (s, node, &remote->sessions) {
 486         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 487     }
 488 }
 489
 490 static void
 491 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 492 {
 493     struct ovsdb_jsonrpc_session *s, *next;
 494
 495     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 496         ovsdb_jsonrpc_session_close(s);
 497     }
 498 }
 499
 500 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 501  * reconnect. */
 502 static void
 503 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 504 {
 505     struct ovsdb_jsonrpc_session *s, *next;
 506
 507     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 508         jsonrpc_session_force_reconnect(s->js);
 509         if (!jsonrpc_session_is_alive(s->js)) {
 510             ovsdb_jsonrpc_session_close(s);
 511         }
 512     }
 513 }
 514
 515 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 516  * 'options'. */
 517 static void
 518 ovsdb_jsonrpc_session_set_all_options(
 519     struct ovsdb_jsonrpc_remote *remote,
 520     const struct ovsdb_jsonrpc_options *options)
 521 {
 522     struct ovsdb_jsonrpc_session *s;
 523
 524     if (remote->listener) {
 525         int error;
 526
 527         error = pstream_set_dscp(remote->listener, options->dscp);
 528         if (error) {
 529             VLOG_ERR("%s: set_dscp failed %s",
 530                      pstream_get_name(remote->listener), strerror(error));
 531         } else {
 532             remote->dscp = options->dscp;
 533         }
 534         /*
 535          * TODO:XXX race window between setting dscp to listening socket
 536          * and accepting socket. Accepted socket may have old dscp value.
 537          * Ignore this race window for now.
 538          */
 539     }
 540     LIST_FOR_EACH (s, node, &remote->sessions) {
 541         ovsdb_jsonrpc_session_set_options(s, options);
 542     }
 543 }
 544
 545 static bool
 546 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
 547                                  struct ovsdb_jsonrpc_remote_status *status)
 548 {
 549     const struct ovsdb_jsonrpc_session *s;
 550     const struct jsonrpc_session *js;
 551     struct ovsdb_lock_waiter *waiter;
 552     struct reconnect_stats rstats;
 553     struct ds locks_held, locks_waiting, locks_lost;
 554
 555     if (list_is_empty(&remote->sessions)) {
 556         return false;
 557     }
 558     s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
 559     js = s->js;
 560
 561     status->is_connected = jsonrpc_session_is_connected(js);
 562     status->last_error = jsonrpc_session_get_status(js);
 563
 564     jsonrpc_session_get_reconnect_stats(js, &rstats);
 565     status->state = rstats.state;
 566     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 567         ? UINT_MAX : rstats.msec_since_connect / 1000;
 568     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 569         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 570
 571     ds_init(&locks_held);
 572     ds_init(&locks_waiting);
 573     ds_init(&locks_lost);
 574     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 575         struct ds *string;
 576
 577         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 578                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 579                   : &locks_lost);
 580         if (string->length) {
 581             ds_put_char(string, ' ');
 582         }
 583         ds_put_cstr(string, waiter->lock_name);
 584     }
 585     status->locks_held = ds_steal_cstr(&locks_held);
 586     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 587     status->locks_lost = ds_steal_cstr(&locks_lost);
 588
 589     status->n_connections = list_size(&remote->sessions);
 590
 591     return true;
 592 }
 593
 594 /* Examines 'request' to determine the database to which it relates, and then
 595  * searches 's' to find that database:
 596  *
 597  *    - If successful, returns the database and sets '*replyp' to NULL.
 598  *
 599  *    - If no such database exists, returns NULL and sets '*replyp' to an
 600  *      appropriate JSON-RPC error reply, owned by the caller. */
 601 static struct ovsdb *
 602 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 603                         const struct jsonrpc_msg *request,
 604                         struct jsonrpc_msg **replyp)
 605 {
 606     struct json_array *params;
 607     struct ovsdb_error *error;
 608     const char *db_name;
 609     struct ovsdb *db;
 610
 611     params = json_array(request->params);
 612     if (!params->n || params->elems[0]->type != JSON_STRING) {
 613         error = ovsdb_syntax_error(
 614             request->params, NULL,
 615             "%s request params must begin with <db-name>", request->method);
 616         goto error;
 617     }
 618
 619     db_name = params->elems[0]->u.string;
 620     db = shash_find_data(&s->up.server->dbs, db_name);
 621     if (!db) {
 622         error = ovsdb_syntax_error(
 623             request->params, "unknown database",
 624             "%s request specifies unknown database %s",
 625             request->method, db_name);
 626         goto error;
 627     }
 628
 629     *replyp = NULL;
 630     return db;
 631
 632 error:
 633     *replyp = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 634     ovsdb_error_destroy(error);
 635     return NULL;
 636 }
 637
 638 static struct ovsdb_error *
 639 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 640                                       const char **lock_namep)
 641 {
 642     const struct json_array *params;
 643
 644     params = json_array(request->params);
 645     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 646         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 647         *lock_namep = NULL;
 648         return ovsdb_syntax_error(request->params, NULL,
 649                                   "%s request params must be <id>",
 650                                   request->method);
 651     }
 652
 653     *lock_namep = json_string(params->elems[0]);
 654     return NULL;
 655 }
 656
 657 static void
 658 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 659                              const char *lock_name,
 660                              const char *method)
 661 {
 662     struct ovsdb_jsonrpc_session *s;
 663     struct json *params;
 664
 665     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 666     params = json_array_create_1(json_string_create(lock_name));
 667     jsonrpc_session_send(s->js, jsonrpc_create_notify(method, params));
 668 }
 669
 670 static struct jsonrpc_msg *
 671 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 672                            struct jsonrpc_msg *request,
 673                            enum ovsdb_lock_mode mode)
 674 {
 675     struct ovsdb_lock_waiter *waiter;
 676     struct jsonrpc_msg *reply;
 677     struct ovsdb_error *error;
 678     struct ovsdb_session *victim;
 679     const char *lock_name;
 680     struct json *result;
 681
 682     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 683     if (error) {
 684         goto error;
 685     }
 686
 687     /* Report error if this session has issued a "lock" or "steal" without a
 688      * matching "unlock" for this lock. */
 689     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 690     if (waiter) {
 691         error = ovsdb_syntax_error(
 692             request->params, NULL,
 693             "must issue \"unlock\" before new \"%s\"", request->method);
 694         goto error;
 695     }
 696
 697     /* Get the lock, add us as a waiter. */
 698     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 699                                &victim);
 700     if (victim) {
 701         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 702     }
 703
 704     result = json_object_create();
 705     json_object_put(result, "locked",
 706                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 707
 708     return jsonrpc_create_reply(result, request->id);
 709
 710 error:
 711     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 712     ovsdb_error_destroy(error);
 713     return reply;
 714 }
 715
 716 static void
 717 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 718 {
 719     struct ovsdb_lock_waiter *waiter, *next;
 720
 721     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 722         ovsdb_jsonrpc_session_unlock__(waiter);
 723     }
 724 }
 725
 726 static void
 727 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 728 {
 729     struct ovsdb_lock *lock = waiter->lock;
 730
 731     if (lock) {
 732         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 733         if (new_owner) {
 734             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 735         } else {
 736             /* ovsdb_server_lock() might have freed 'lock'. */
 737         }
 738     }
 739
 740     ovsdb_lock_waiter_destroy(waiter);
 741 }
 742
 743 static struct jsonrpc_msg *
 744 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 745                              struct jsonrpc_msg *request)
 746 {
 747     struct ovsdb_lock_waiter *waiter;
 748     struct jsonrpc_msg *reply;
 749     struct ovsdb_error *error;
 750     const char *lock_name;
 751
 752     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 753     if (error) {
 754         goto error;
 755     }
 756
 757     /* Report error if this session has not issued a "lock" or "steal" for this
 758      * lock. */
 759     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 760     if (!waiter) {
 761         error = ovsdb_syntax_error(
 762             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 763         goto error;
 764     }
 765
 766     ovsdb_jsonrpc_session_unlock__(waiter);
 767
 768     return jsonrpc_create_reply(json_object_create(), request->id);
 769
 770 error:
 771     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 772     ovsdb_error_destroy(error);
 773     return reply;
 774 }
 775
 776 static struct jsonrpc_msg *
 777 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 778                     struct jsonrpc_msg *request)
 779 {
 780     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 781     request->id = NULL;
 782     request->params = NULL;
 783     jsonrpc_msg_destroy(request);
 784     return NULL;
 785 }
 786
 787 static void
 788 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 789                                   struct jsonrpc_msg *request)
 790 {
 791     struct jsonrpc_msg *reply;
 792
 793     if (!strcmp(request->method, "transact")) {
 794         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 795         if (!reply) {
 796             reply = execute_transaction(s, db, request);
 797         }
 798     } else if (!strcmp(request->method, "monitor")) {
 799         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 800         if (!reply) {
 801             reply = jsonrpc_create_reply(
 802                 ovsdb_jsonrpc_monitor_create(s, db, request->params),
 803                 request->id);
 804         }
 805     } else if (!strcmp(request->method, "monitor_cancel")) {
 806         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 807                                              request->id);
 808     } else if (!strcmp(request->method, "get_schema")) {
 809         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 810         if (!reply) {
 811             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 812                                          request->id);
 813         }
 814     } else if (!strcmp(request->method, "list_dbs")) {
 815         size_t n_dbs = shash_count(&s->up.server->dbs);
 816         struct shash_node *node;
 817         struct json **dbs;
 818         size_t i;
 819
 820         dbs = xmalloc(n_dbs * sizeof *dbs);
 821         i = 0;
 822         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 823             dbs[i++] = json_string_create(node->name);
 824         }
 825         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 826                                      request->id);
 827     } else if (!strcmp(request->method, "lock")) {
 828         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 829     } else if (!strcmp(request->method, "steal")) {
 830         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 831     } else if (!strcmp(request->method, "unlock")) {
 832         reply = ovsdb_jsonrpc_session_unlock(s, request);
 833     } else if (!strcmp(request->method, "echo")) {
 834         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 835     } else {
 836         reply = jsonrpc_create_error(json_string_create("unknown method"),
 837                                      request->id);
 838     }
 839
 840     if (reply) {
 841         jsonrpc_msg_destroy(request);
 842         jsonrpc_session_send(s->js, reply);
 843     }
 844 }
 845
 846 static void
 847 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 848 {
 849     if (json_array(request->params)->n == 1) {
 850         struct ovsdb_jsonrpc_trigger *t;
 851         struct json *id;
 852
 853         id = request->params->u.array.elems[0];
 854         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 855         if (t) {
 856             ovsdb_jsonrpc_trigger_complete(t);
 857         }
 858     }
 859 }
 860
 861 static void
 862 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 863                                  struct jsonrpc_msg *request)
 864 {
 865     if (!strcmp(request->method, "cancel")) {
 866         execute_cancel(s, request);
 867     }
 868     jsonrpc_msg_destroy(request);
 869 }
 870 \f
 871 /* JSON-RPC database server triggers.
 872  *
 873  * (Every transaction is treated as a trigger even if it doesn't actually have
 874  * any "wait" operations.) */
 875
 876 struct ovsdb_jsonrpc_trigger {
 877     struct ovsdb_trigger trigger;
 878     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 879     struct json *id;
 880 };
 881
 882 static void
 883 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 884                              struct json *id, struct json *params)
 885 {
 886     struct ovsdb_jsonrpc_trigger *t;
 887     size_t hash;
 888
 889     /* Check for duplicate ID. */
 890     hash = json_hash(id, 0);
 891     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 892     if (t) {
 893         struct jsonrpc_msg *msg;
 894
 895         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 896                                    id);
 897         jsonrpc_session_send(s->js, msg);
 898         json_destroy(id);
 899         json_destroy(params);
 900         return;
 901     }
 902
 903     /* Insert into trigger table. */
 904     t = xmalloc(sizeof *t);
 905     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 906     t->id = id;
 907     hmap_insert(&s->triggers, &t->hmap_node, hash);
 908
 909     /* Complete early if possible. */
 910     if (ovsdb_trigger_is_complete(&t->trigger)) {
 911         ovsdb_jsonrpc_trigger_complete(t);
 912     }
 913 }
 914
 915 static struct ovsdb_jsonrpc_trigger *
 916 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 917                            const struct json *id, size_t hash)
 918 {
 919     struct ovsdb_jsonrpc_trigger *t;
 920
 921     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
 922         if (json_equal(t->id, id)) {
 923             return t;
 924         }
 925     }
 926
 927     return NULL;
 928 }
 929
 930 static void
 931 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 932 {
 933     struct ovsdb_jsonrpc_session *s;
 934
 935     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 936
 937     if (jsonrpc_session_is_connected(s->js)) {
 938         struct jsonrpc_msg *reply;
 939         struct json *result;
 940
 941         result = ovsdb_trigger_steal_result(&t->trigger);
 942         if (result) {
 943             reply = jsonrpc_create_reply(result, t->id);
 944         } else {
 945             reply = jsonrpc_create_error(json_string_create("canceled"),
 946                                          t->id);
 947         }
 948         jsonrpc_session_send(s->js, reply);
 949     }
 950
 951     json_destroy(t->id);
 952     ovsdb_trigger_destroy(&t->trigger);
 953     hmap_remove(&s->triggers, &t->hmap_node);
 954     free(t);
 955 }
 956
 957 static void
 958 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
 959 {
 960     struct ovsdb_jsonrpc_trigger *t, *next;
 961     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
 962         ovsdb_jsonrpc_trigger_complete(t);
 963     }
 964 }
 965
 966 static void
 967 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
 968 {
 969     while (!list_is_empty(&s->up.completions)) {
 970         struct ovsdb_jsonrpc_trigger *t
 971             = CONTAINER_OF(s->up.completions.next,
 972                            struct ovsdb_jsonrpc_trigger, trigger.node);
 973         ovsdb_jsonrpc_trigger_complete(t);
 974     }
 975 }
 976 \f
 977 /* JSON-RPC database table monitors. */
 978
 979 enum ovsdb_jsonrpc_monitor_selection {
 980     OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
 981     OJMS_INSERT = 1 << 1,       /* New rows. */
 982     OJMS_DELETE = 1 << 2,       /* Deleted rows. */
 983     OJMS_MODIFY = 1 << 3        /* Modified rows. */
 984 };
 985
 986 /* A particular column being monitored. */
 987 struct ovsdb_jsonrpc_monitor_column {
 988     const struct ovsdb_column *column;
 989     enum ovsdb_jsonrpc_monitor_selection select;
 990 };
 991
 992 /* A particular table being monitored. */
 993 struct ovsdb_jsonrpc_monitor_table {
 994     const struct ovsdb_table *table;
 995
 996     /* This is the union (bitwise-OR) of the 'select' values in all of the
 997      * members of 'columns' below. */
 998     enum ovsdb_jsonrpc_monitor_selection select;
 999
1000     /* Columns being monitored. */
1001     struct ovsdb_jsonrpc_monitor_column *columns;
1002     size_t n_columns;
1003 };
1004
1005 /* A collection of tables being monitored. */
1006 struct ovsdb_jsonrpc_monitor {
1007     struct ovsdb_replica replica;
1008     struct ovsdb_jsonrpc_session *session;
1009     struct ovsdb *db;
1010     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1011
1012     struct json *monitor_id;
1013     struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
1014 };
1015
1016 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
1017
1018 struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
1019     struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
1020 static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
1021 static struct json *ovsdb_jsonrpc_monitor_get_initial(
1022     const struct ovsdb_jsonrpc_monitor *);
1023
1024 static bool
1025 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1026 {
1027     const struct json *json;
1028
1029     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1030     return json ? json_boolean(json) : default_value;
1031 }
1032
1033 struct ovsdb_jsonrpc_monitor *
1034 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1035                            const struct json *monitor_id)
1036 {
1037     struct ovsdb_jsonrpc_monitor *m;
1038
1039     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1040         if (json_equal(m->monitor_id, monitor_id)) {
1041             return m;
1042         }
1043     }
1044
1045     return NULL;
1046 }
1047
1048 static void
1049 ovsdb_jsonrpc_add_monitor_column(struct ovsdb_jsonrpc_monitor_table *mt,
1050                                  const struct ovsdb_column *column,
1051                                  enum ovsdb_jsonrpc_monitor_selection select,
1052                                  size_t *allocated_columns)
1053 {
1054     struct ovsdb_jsonrpc_monitor_column *c;
1055
1056     if (mt->n_columns >= *allocated_columns) {
1057         mt->columns = x2nrealloc(mt->columns, allocated_columns,
1058                                  sizeof *mt->columns);
1059     }
1060
1061     c = &mt->columns[mt->n_columns++];
1062     c->column = column;
1063     c->select = select;
1064 }
1065
1066 static int
1067 compare_ovsdb_jsonrpc_monitor_column(const void *a_, const void *b_)
1068 {
1069     const struct ovsdb_jsonrpc_monitor_column *a = a_;
1070     const struct ovsdb_jsonrpc_monitor_column *b = b_;
1071
1072     return a->column < b->column ? -1 : a->column > b->column;
1073 }
1074
1075 static struct ovsdb_error * WARN_UNUSED_RESULT
1076 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
1077                                     const struct json *monitor_request,
1078                                     size_t *allocated_columns)
1079 {
1080     const struct ovsdb_table_schema *ts = mt->table->schema;
1081     enum ovsdb_jsonrpc_monitor_selection select;
1082     const struct json *columns, *select_json;
1083     struct ovsdb_parser parser;
1084     struct ovsdb_error *error;
1085
1086     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1087     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1088     select_json = ovsdb_parser_member(&parser, "select",
1089                                       OP_OBJECT | OP_OPTIONAL);
1090     error = ovsdb_parser_finish(&parser);
1091     if (error) {
1092         return error;
1093     }
1094
1095     if (select_json) {
1096         select = 0;
1097         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1098         if (parse_bool(&parser, "initial", true)) {
1099             select |= OJMS_INITIAL;
1100         }
1101         if (parse_bool(&parser, "insert", true)) {
1102             select |= OJMS_INSERT;
1103         }
1104         if (parse_bool(&parser, "delete", true)) {
1105             select |= OJMS_DELETE;
1106         }
1107         if (parse_bool(&parser, "modify", true)) {
1108             select |= OJMS_MODIFY;
1109         }
1110         error = ovsdb_parser_finish(&parser);
1111         if (error) {
1112             return error;
1113         }
1114     } else {
1115         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1116     }
1117     mt->select |= select;
1118
1119     if (columns) {
1120         size_t i;
1121
1122         if (columns->type != JSON_ARRAY) {
1123             return ovsdb_syntax_error(columns, NULL,
1124                                       "array of column names expected");
1125         }
1126
1127         for (i = 0; i < columns->u.array.n; i++) {
1128             const struct ovsdb_column *column;
1129             const char *s;
1130
1131             if (columns->u.array.elems[i]->type != JSON_STRING) {
1132                 return ovsdb_syntax_error(columns, NULL,
1133                                           "array of column names expected");
1134             }
1135
1136             s = columns->u.array.elems[i]->u.string;
1137             column = shash_find_data(&mt->table->schema->columns, s);
1138             if (!column) {
1139                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1140                                           "column name", s);
1141             }
1142             ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1143                                              allocated_columns);
1144         }
1145     } else {
1146         struct shash_node *node;
1147
1148         SHASH_FOR_EACH (node, &ts->columns) {
1149             const struct ovsdb_column *column = node->data;
1150             if (column->index != OVSDB_COL_UUID) {
1151                 ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1152                                                  allocated_columns);
1153             }
1154         }
1155     }
1156
1157     return NULL;
1158 }
1159
1160 static struct json *
1161 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1162                              struct json *params)
1163 {
1164     struct ovsdb_jsonrpc_monitor *m = NULL;
1165     struct json *monitor_id, *monitor_requests;
1166     struct ovsdb_error *error = NULL;
1167     struct shash_node *node;
1168     struct json *json;
1169
1170     if (json_array(params)->n != 3) {
1171         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1172         goto error;
1173     }
1174     monitor_id = params->u.array.elems[1];
1175     monitor_requests = params->u.array.elems[2];
1176     if (monitor_requests->type != JSON_OBJECT) {
1177         error = ovsdb_syntax_error(monitor_requests, NULL,
1178                                    "monitor-requests must be object");
1179         goto error;
1180     }
1181
1182     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1183         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1184         goto error;
1185     }
1186
1187     m = xzalloc(sizeof *m);
1188     ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
1189     ovsdb_add_replica(db, &m->replica);
1190     m->session = s;
1191     m->db = db;
1192     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1193     m->monitor_id = json_clone(monitor_id);
1194     shash_init(&m->tables);
1195
1196     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1197         const struct ovsdb_table *table;
1198         struct ovsdb_jsonrpc_monitor_table *mt;
1199         size_t allocated_columns;
1200         const struct json *mr_value;
1201         size_t i;
1202
1203         table = ovsdb_get_table(m->db, node->name);
1204         if (!table) {
1205             error = ovsdb_syntax_error(NULL, NULL,
1206                                        "no table named %s", node->name);
1207             goto error;
1208         }
1209
1210         mt = xzalloc(sizeof *mt);
1211         mt->table = table;
1212         shash_add(&m->tables, table->schema->name, mt);
1213
1214         /* Parse columns. */
1215         mr_value = node->data;
1216         allocated_columns = 0;
1217         if (mr_value->type == JSON_ARRAY) {
1218             const struct json_array *array = &mr_value->u.array;
1219
1220             for (i = 0; i < array->n; i++) {
1221                 error = ovsdb_jsonrpc_parse_monitor_request(
1222                     mt, array->elems[i], &allocated_columns);
1223                 if (error) {
1224                     goto error;
1225                 }
1226             }
1227         } else {
1228             error = ovsdb_jsonrpc_parse_monitor_request(
1229                 mt, mr_value, &allocated_columns);
1230             if (error) {
1231                 goto error;
1232             }
1233         }
1234
1235         /* Check for duplicate columns. */
1236         qsort(mt->columns, mt->n_columns, sizeof *mt->columns,
1237               compare_ovsdb_jsonrpc_monitor_column);
1238         for (i = 1; i < mt->n_columns; i++) {
1239             if (mt->columns[i].column == mt->columns[i - 1].column) {
1240                 error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1241                                            "mentioned more than once",
1242                                            mt->columns[i].column->name);
1243                 goto error;
1244             }
1245         }
1246     }
1247
1248     return ovsdb_jsonrpc_monitor_get_initial(m);
1249
1250 error:
1251     if (m) {
1252         ovsdb_remove_replica(m->db, &m->replica);
1253     }
1254
1255     json = ovsdb_error_to_json(error);
1256     ovsdb_error_destroy(error);
1257     return json;
1258 }
1259
1260 static struct jsonrpc_msg *
1261 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1262                              struct json_array *params,
1263                              const struct json *request_id)
1264 {
1265     if (params->n != 1) {
1266         return jsonrpc_create_error(json_string_create("invalid parameters"),
1267                                     request_id);
1268     } else {
1269         struct ovsdb_jsonrpc_monitor *m;
1270
1271         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1272         if (!m) {
1273             return jsonrpc_create_error(json_string_create("unknown monitor"),
1274                                         request_id);
1275         } else {
1276             ovsdb_remove_replica(m->db, &m->replica);
1277             return jsonrpc_create_reply(json_object_create(), request_id);
1278         }
1279     }
1280 }
1281
1282 static void
1283 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1284 {
1285     struct ovsdb_jsonrpc_monitor *m, *next;
1286
1287     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1288         ovsdb_remove_replica(m->db, &m->replica);
1289     }
1290 }
1291
1292 static struct ovsdb_jsonrpc_monitor *
1293 ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
1294 {
1295     assert(replica->class == &ovsdb_jsonrpc_replica_class);
1296     return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
1297 }
1298
1299 struct ovsdb_jsonrpc_monitor_aux {
1300     bool initial;               /* Sending initial contents of table? */
1301     const struct ovsdb_jsonrpc_monitor *monitor;
1302     struct json *json;          /* JSON for the whole transaction. */
1303
1304     /* Current table.  */
1305     struct ovsdb_jsonrpc_monitor_table *mt;
1306     struct json *table_json;    /* JSON for table's transaction. */
1307 };
1308
1309 static bool
1310 any_reportable_change(const struct ovsdb_jsonrpc_monitor_table *mt,
1311                       const unsigned long int *changed)
1312 {
1313     size_t i;
1314
1315     for (i = 0; i < mt->n_columns; i++) {
1316         const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1317         unsigned int idx = c->column->index;
1318
1319         if (c->select & OJMS_MODIFY && bitmap_is_set(changed, idx)) {
1320             return true;
1321         }
1322     }
1323
1324     return false;
1325 }
1326
1327 static bool
1328 ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
1329                                 const struct ovsdb_row *new,
1330                                 const unsigned long int *changed,
1331                                 void *aux_)
1332 {
1333     struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
1334     const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
1335     struct ovsdb_table *table = new ? new->table : old->table;
1336     enum ovsdb_jsonrpc_monitor_selection type;
1337     struct json *old_json, *new_json;
1338     struct json *row_json;
1339     char uuid[UUID_LEN + 1];
1340     size_t i;
1341
1342     if (!aux->mt || table != aux->mt->table) {
1343         aux->mt = shash_find_data(&m->tables, table->schema->name);
1344         aux->table_json = NULL;
1345         if (!aux->mt) {
1346             /* We don't care about rows in this table at all.  Tell the caller
1347              * to skip it.  */
1348             return false;
1349         }
1350     }
1351
1352     type = (aux->initial ? OJMS_INITIAL
1353             : !old ? OJMS_INSERT
1354             : !new ? OJMS_DELETE
1355             : OJMS_MODIFY);
1356     if (!(aux->mt->select & type)) {
1357         /* We don't care about this type of change (but do want to be called
1358          * back for changes to other rows in the same table). */
1359         return true;
1360     }
1361
1362     if (type == OJMS_MODIFY && !any_reportable_change(aux->mt, changed)) {
1363         /* Nothing of interest changed. */
1364         return true;
1365     }
1366
1367     old_json = new_json = NULL;
1368     if (type & (OJMS_DELETE | OJMS_MODIFY)) {
1369         old_json = json_object_create();
1370     }
1371     if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1372         new_json = json_object_create();
1373     }
1374     for (i = 0; i < aux->mt->n_columns; i++) {
1375         const struct ovsdb_jsonrpc_monitor_column *c = &aux->mt->columns[i];
1376         const struct ovsdb_column *column = c->column;
1377         unsigned int idx = c->column->index;
1378
1379         if (!(type & c->select)) {
1380             /* We don't care about this type of change for this particular
1381              * column (but we will care about it for some other column). */
1382             continue;
1383         }
1384
1385         if ((type == OJMS_MODIFY && bitmap_is_set(changed, idx))
1386             || type == OJMS_DELETE) {
1387             json_object_put(old_json, column->name,
1388                             ovsdb_datum_to_json(&old->fields[idx],
1389                                                 &column->type));
1390         }
1391         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1392             json_object_put(new_json, column->name,
1393                             ovsdb_datum_to_json(&new->fields[idx],
1394                                                 &column->type));
1395         }
1396     }
1397
1398     /* Create JSON object for transaction overall. */
1399     if (!aux->json) {
1400         aux->json = json_object_create();
1401     }
1402
1403     /* Create JSON object for transaction on this table. */
1404     if (!aux->table_json) {
1405         aux->table_json = json_object_create();
1406         json_object_put(aux->json, aux->mt->table->schema->name,
1407                         aux->table_json);
1408     }
1409
1410     /* Create JSON object for transaction on this row. */
1411     row_json = json_object_create();
1412     if (old_json) {
1413         json_object_put(row_json, "old", old_json);
1414     }
1415     if (new_json) {
1416         json_object_put(row_json, "new", new_json);
1417     }
1418
1419     /* Add JSON row to JSON table. */
1420     snprintf(uuid, sizeof uuid,
1421              UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
1422     json_object_put(aux->table_json, uuid, row_json);
1423
1424     return true;
1425 }
1426
1427 static void
1428 ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
1429                                const struct ovsdb_jsonrpc_monitor *m,
1430                                bool initial)
1431 {
1432     aux->initial = initial;
1433     aux->monitor = m;
1434     aux->json = NULL;
1435     aux->mt = NULL;
1436     aux->table_json = NULL;
1437 }
1438
1439 static struct ovsdb_error *
1440 ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
1441                              const struct ovsdb_txn *txn,
1442                              bool durable OVS_UNUSED)
1443 {
1444     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1445     struct ovsdb_jsonrpc_monitor_aux aux;
1446
1447     ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
1448     ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
1449     if (aux.json) {
1450         struct jsonrpc_msg *msg;
1451         struct json *params;
1452
1453         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
1454                                      aux.json);
1455         msg = jsonrpc_create_notify("update", params);
1456         jsonrpc_session_send(aux.monitor->session->js, msg);
1457     }
1458
1459     return NULL;
1460 }
1461
1462 static struct json *
1463 ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
1464 {
1465     struct ovsdb_jsonrpc_monitor_aux aux;
1466     struct shash_node *node;
1467
1468     ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
1469     SHASH_FOR_EACH (node, &m->tables) {
1470         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1471
1472         if (mt->select & OJMS_INITIAL) {
1473             struct ovsdb_row *row;
1474
1475             HMAP_FOR_EACH (row, hmap_node, &mt->table->rows) {
1476                 ovsdb_jsonrpc_monitor_change_cb(NULL, row, NULL, &aux);
1477             }
1478         }
1479     }
1480     return aux.json ? aux.json : json_object_create();
1481 }
1482
1483 static void
1484 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
1485 {
1486     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1487     struct shash_node *node;
1488
1489     json_destroy(m->monitor_id);
1490     SHASH_FOR_EACH (node, &m->tables) {
1491         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1492         free(mt->columns);
1493         free(mt);
1494     }
1495     shash_destroy(&m->tables);
1496     hmap_remove(&m->session->monitors, &m->node);
1497     free(m);
1498 }
1499
1500 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
1501     ovsdb_jsonrpc_monitor_commit,
1502     ovsdb_jsonrpc_monitor_destroy
1503 };