ovsdb/jsonrpc-server.c

   1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <config.h>
  17
  18 #include "jsonrpc-server.h"
  19
  20 #include <errno.h>
  21
  22 #include "bitmap.h"
  23 #include "column.h"
  24 #include "dynamic-string.h"
  25 #include "json.h"
  26 #include "jsonrpc.h"
  27 #include "ovsdb-error.h"
  28 #include "ovsdb-parser.h"
  29 #include "ovsdb.h"
  30 #include "reconnect.h"
  31 #include "row.h"
  32 #include "server.h"
  33 #include "simap.h"
  34 #include "stream.h"
  35 #include "table.h"
  36 #include "timeval.h"
  37 #include "transaction.h"
  38 #include "trigger.h"
  39 #include "vlog.h"
  40
  41 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
  42
  43 struct ovsdb_jsonrpc_remote;
  44 struct ovsdb_jsonrpc_session;
  45
  46 /* Message rate-limiting. */
  47 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  48
  49 /* Sessions. */
  50 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  51     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  52 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  53 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  54 static void ovsdb_jsonrpc_session_get_memory_usage_all(
  55     const struct ovsdb_jsonrpc_remote *, struct simap *usage);
  56 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  57 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  58 static void ovsdb_jsonrpc_session_set_all_options(
  59     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  60 static bool ovsdb_jsonrpc_session_get_status(
  61     const struct ovsdb_jsonrpc_remote *,
  62     struct ovsdb_jsonrpc_remote_status *);
  63 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  64 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  65
  66 /* Triggers. */
  67 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  68                                          struct ovsdb *,
  69                                          struct json *id, struct json *params);
  70 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  71     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  72 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  73 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  74 static void ovsdb_jsonrpc_trigger_complete_done(
  75     struct ovsdb_jsonrpc_session *);
  76
  77 /* Monitors. */
  78 static struct json *ovsdb_jsonrpc_monitor_create(
  79     struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params);
  80 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  81     struct ovsdb_jsonrpc_session *,
  82     struct json_array *params,
  83     const struct json *request_id);
  84 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
  85 static size_t ovsdb_jsonrpc_monitor_json_length_all(
  86     struct ovsdb_jsonrpc_session *);
  87 \f
  88 /* JSON-RPC database server. */
  89
  90 struct ovsdb_jsonrpc_server {
  91     struct ovsdb_server up;
  92     unsigned int n_sessions, max_sessions;
  93     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
  94 };
  95
  96 /* A configured remote.  This is either a passive stream listener plus a list
  97  * of the currently connected sessions, or a list of exactly one active
  98  * session. */
  99 struct ovsdb_jsonrpc_remote {
 100     struct ovsdb_jsonrpc_server *server;
 101     struct pstream *listener;   /* Listener, if passive. */
 102     struct list sessions;       /* List of "struct ovsdb_jsonrpc_session"s. */
 103     uint8_t dscp;
 104 };
 105
 106 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 107     struct ovsdb_jsonrpc_server *, const char *name,
 108     const struct ovsdb_jsonrpc_options *options
 109 );
 110 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 111
 112 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 113  *
 114  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 115  * which 'server' should provide access. */
 116 struct ovsdb_jsonrpc_server *
 117 ovsdb_jsonrpc_server_create(void)
 118 {
 119     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 120     ovsdb_server_init(&server->up);
 121     server->max_sessions = 64;
 122     shash_init(&server->remotes);
 123     return server;
 124 }
 125
 126 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 127  * successful, false if 'db''s name is the same as some database already in
 128  * 'server'. */
 129 bool
 130 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 131 {
 132     return ovsdb_server_add_db(&svr->up, db);
 133 }
 134
 135 void
 136 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 137 {
 138     struct shash_node *node, *next;
 139
 140     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 141         ovsdb_jsonrpc_server_del_remote(node);
 142     }
 143     shash_destroy(&svr->remotes);
 144     ovsdb_server_destroy(&svr->up);
 145     free(svr);
 146 }
 147
 148 struct ovsdb_jsonrpc_options *
 149 ovsdb_jsonrpc_default_options(const char *target)
 150 {
 151     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 152     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 153     options->probe_interval = (stream_or_pstream_needs_probes(target)
 154                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 155                                : 0);
 156     return options;
 157 }
 158
 159 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 160  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 161  *
 162  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 163  * "tcp:1.2.3.4". */
 164 void
 165 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 166                                  const struct shash *new_remotes)
 167 {
 168     struct shash_node *node, *next;
 169
 170     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 171         if (!shash_find(new_remotes, node->name)) {
 172             VLOG_INFO("%s: remote deconfigured", node->name);
 173             ovsdb_jsonrpc_server_del_remote(node);
 174         }
 175     }
 176     SHASH_FOR_EACH (node, new_remotes) {
 177         const struct ovsdb_jsonrpc_options *options = node->data;
 178         struct ovsdb_jsonrpc_remote *remote;
 179
 180         remote = shash_find_data(&svr->remotes, node->name);
 181         if (!remote) {
 182             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 183             if (!remote) {
 184                 continue;
 185             }
 186         }
 187
 188         ovsdb_jsonrpc_session_set_all_options(remote, options);
 189     }
 190 }
 191
 192 static struct ovsdb_jsonrpc_remote *
 193 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 194                                 const char *name,
 195                                 const struct ovsdb_jsonrpc_options *options)
 196 {
 197     struct ovsdb_jsonrpc_remote *remote;
 198     struct pstream *listener;
 199     int error;
 200
 201     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 202     if (error && error != EAFNOSUPPORT) {
 203         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, strerror(error));
 204         return NULL;
 205     }
 206
 207     remote = xmalloc(sizeof *remote);
 208     remote->server = svr;
 209     remote->listener = listener;
 210     list_init(&remote->sessions);
 211     remote->dscp = options->dscp;
 212     shash_add(&svr->remotes, name, remote);
 213
 214     if (!listener) {
 215         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true));
 216     }
 217     return remote;
 218 }
 219
 220 static void
 221 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 222 {
 223     struct ovsdb_jsonrpc_remote *remote = node->data;
 224
 225     ovsdb_jsonrpc_session_close_all(remote);
 226     pstream_close(remote->listener);
 227     shash_delete(&remote->server->remotes, node);
 228     free(remote);
 229 }
 230
 231 /* Stores status information for the remote named 'target', which should have
 232  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 233  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 234  * a remote named 'target' or if that remote is an inbound remote that has no
 235  * active connections) returns false.  On failure, 'status' will be zeroed.
 236  */
 237 bool
 238 ovsdb_jsonrpc_server_get_remote_status(
 239     const struct ovsdb_jsonrpc_server *svr, const char *target,
 240     struct ovsdb_jsonrpc_remote_status *status)
 241 {
 242     const struct ovsdb_jsonrpc_remote *remote;
 243
 244     memset(status, 0, sizeof *status);
 245
 246     remote = shash_find_data(&svr->remotes, target);
 247     return remote && ovsdb_jsonrpc_session_get_status(remote, status);
 248 }
 249
 250 void
 251 ovsdb_jsonrpc_server_free_remote_status(
 252     struct ovsdb_jsonrpc_remote_status *status)
 253 {
 254     free(status->locks_held);
 255     free(status->locks_waiting);
 256     free(status->locks_lost);
 257 }
 258
 259 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 260  * reconnect. */
 261 void
 262 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 263 {
 264     struct shash_node *node;
 265
 266     SHASH_FOR_EACH (node, &svr->remotes) {
 267         struct ovsdb_jsonrpc_remote *remote = node->data;
 268
 269         ovsdb_jsonrpc_session_reconnect_all(remote);
 270     }
 271 }
 272
 273 void
 274 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 275 {
 276     struct shash_node *node;
 277
 278     SHASH_FOR_EACH (node, &svr->remotes) {
 279         struct ovsdb_jsonrpc_remote *remote = node->data;
 280
 281         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 282             struct stream *stream;
 283             int error;
 284
 285             error = pstream_accept(remote->listener, &stream);
 286             if (!error) {
 287                 struct jsonrpc_session *js;
 288                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
 289                                                      remote->dscp);
 290                 ovsdb_jsonrpc_session_create(remote, js);
 291             } else if (error != EAGAIN) {
 292                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 293                              pstream_get_name(remote->listener),
 294                              strerror(error));
 295             }
 296         }
 297
 298         ovsdb_jsonrpc_session_run_all(remote);
 299     }
 300 }
 301
 302 void
 303 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 304 {
 305     struct shash_node *node;
 306
 307     SHASH_FOR_EACH (node, &svr->remotes) {
 308         struct ovsdb_jsonrpc_remote *remote = node->data;
 309
 310         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 311             pstream_wait(remote->listener);
 312         }
 313
 314         ovsdb_jsonrpc_session_wait_all(remote);
 315     }
 316 }
 317
 318 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 319  * memory_report(). */
 320 void
 321 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 322                                       struct simap *usage)
 323 {
 324     struct shash_node *node;
 325
 326     simap_increase(usage, "sessions", svr->n_sessions);
 327     SHASH_FOR_EACH (node, &svr->remotes) {
 328         struct ovsdb_jsonrpc_remote *remote = node->data;
 329
 330         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 331     }
 332 }
 333 \f
 334 /* JSON-RPC database server session. */
 335
 336 struct ovsdb_jsonrpc_session {
 337     struct list node;           /* Element in remote's sessions list. */
 338     struct ovsdb_session up;
 339     struct ovsdb_jsonrpc_remote *remote;
 340     size_t backlog_threshold;   /* See ovsdb_jsonrpc_session_run(). */
 341     size_t reply_backlog;
 342
 343     /* Triggers. */
 344     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 345
 346     /* Monitors. */
 347     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 348
 349     /* Network connectivity. */
 350     struct jsonrpc_session *js;  /* JSON-RPC session. */
 351     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 352 };
 353
 354 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 355 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 356 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 357 static void ovsdb_jsonrpc_session_get_memory_usage(
 358     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 359 static void ovsdb_jsonrpc_session_set_options(
 360     struct ovsdb_jsonrpc_session *, const struct ovsdb_jsonrpc_options *);
 361 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 362                                              struct jsonrpc_msg *);
 363 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 364                                              struct jsonrpc_msg *);
 365
 366 static struct ovsdb_jsonrpc_session *
 367 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 368                              struct jsonrpc_session *js)
 369 {
 370     struct ovsdb_jsonrpc_session *s;
 371
 372     s = xzalloc(sizeof *s);
 373     ovsdb_session_init(&s->up, &remote->server->up);
 374     s->remote = remote;
 375     list_push_back(&remote->sessions, &s->node);
 376     hmap_init(&s->triggers);
 377     hmap_init(&s->monitors);
 378     s->reply_backlog = 0;
 379     s->backlog_threshold = 1024 * 1024;
 380     s->js = js;
 381     s->js_seqno = jsonrpc_session_get_seqno(js);
 382
 383     remote->server->n_sessions++;
 384
 385     return s;
 386 }
 387
 388 static void
 389 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 390 {
 391     ovsdb_jsonrpc_monitor_remove_all(s);
 392     ovsdb_jsonrpc_session_unlock_all(s);
 393     ovsdb_jsonrpc_trigger_complete_all(s);
 394
 395     hmap_destroy(&s->monitors);
 396     hmap_destroy(&s->triggers);
 397
 398     jsonrpc_session_close(s->js);
 399     list_remove(&s->node);
 400     s->remote->server->n_sessions--;
 401     ovsdb_session_destroy(&s->up);
 402     free(s);
 403 }
 404
 405 static int
 406 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 407 {
 408     size_t backlog;
 409
 410     jsonrpc_session_run(s->js);
 411     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 412         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 413         ovsdb_jsonrpc_trigger_complete_all(s);
 414         ovsdb_jsonrpc_monitor_remove_all(s);
 415         ovsdb_jsonrpc_session_unlock_all(s);
 416     }
 417
 418     ovsdb_jsonrpc_trigger_complete_done(s);
 419
 420     backlog = jsonrpc_session_get_backlog(s->js);
 421     if (!backlog) {
 422         struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
 423         if (msg) {
 424             if (msg->type == JSONRPC_REQUEST) {
 425                 ovsdb_jsonrpc_session_got_request(s, msg);
 426             } else if (msg->type == JSONRPC_NOTIFY) {
 427                 ovsdb_jsonrpc_session_got_notify(s, msg);
 428             } else {
 429                 VLOG_WARN("%s: received unexpected %s message",
 430                           jsonrpc_session_get_name(s->js),
 431                           jsonrpc_msg_type_to_string(msg->type));
 432                 jsonrpc_session_force_reconnect(s->js);
 433                 jsonrpc_msg_destroy(msg);
 434             }
 435         }
 436         s->reply_backlog = jsonrpc_session_get_backlog(s->js);
 437     } else if (backlog > s->reply_backlog + s->backlog_threshold) {
 438         /* We have a lot of data queued to send to the client.  The data is
 439          * likely to be mostly monitor updates.  It is unlikely that the
 440          * monitor updates are due to transactions by 's', because we will not
 441          * let 's' make any more transactions until it drains its backlog to 0
 442          * (see previous 'if' case).  So the monitor updates are probably due
 443          * to transactions made by database clients other than 's'.  We can't
 444          * fix that by preventing 's' from executing more transactions.  We
 445          * could fix it by preventing every client from executing transactions,
 446          * but then one slow or hung client could prevent other clients from
 447          * doing useful work.
 448          *
 449          * Our solution is to cap the maximum backlog to O(1) in the amount of
 450          * data in the database.  If the backlog exceeds that amount, then we
 451          * disconnect the client.  When it reconnects, it can fetch the entire
 452          * contents of the database using less data than was previously
 453          * backlogged. */
 454         size_t monitor_length;
 455
 456         monitor_length = ovsdb_jsonrpc_monitor_json_length_all(s);
 457         if (backlog > s->reply_backlog + monitor_length * 2) {
 458             VLOG_INFO("%s: %zu bytes backlogged but a complete replica "
 459                       "would only take %zu bytes, disconnecting",
 460                       jsonrpc_session_get_name(s->js),
 461                       backlog - s->reply_backlog, monitor_length);
 462             jsonrpc_session_force_reconnect(s->js);
 463         } else {
 464             /* The backlog is not unreasonably big.  Only check again after it
 465              * becomes much bigger. */
 466             s->backlog_threshold = 2 * MAX(s->backlog_threshold * 2,
 467                                            monitor_length);
 468         }
 469     }
 470     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 471 }
 472
 473 static void
 474 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 475                                   const struct ovsdb_jsonrpc_options *options)
 476 {
 477     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 478     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 479     jsonrpc_session_set_dscp(session->js, options->dscp);
 480 }
 481
 482 static void
 483 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 484 {
 485     struct ovsdb_jsonrpc_session *s, *next;
 486
 487     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 488         int error = ovsdb_jsonrpc_session_run(s);
 489         if (error) {
 490             ovsdb_jsonrpc_session_close(s);
 491         }
 492     }
 493 }
 494
 495 static void
 496 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 497 {
 498     jsonrpc_session_wait(s->js);
 499     if (!jsonrpc_session_get_backlog(s->js)) {
 500         jsonrpc_session_recv_wait(s->js);
 501     }
 502 }
 503
 504 static void
 505 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 506 {
 507     struct ovsdb_jsonrpc_session *s;
 508
 509     LIST_FOR_EACH (s, node, &remote->sessions) {
 510         ovsdb_jsonrpc_session_wait(s);
 511     }
 512 }
 513
 514 static void
 515 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 516                                        struct simap *usage)
 517 {
 518     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 519     simap_increase(usage, "monitors", hmap_count(&s->monitors));
 520     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 521 }
 522
 523 static void
 524 ovsdb_jsonrpc_session_get_memory_usage_all(
 525     const struct ovsdb_jsonrpc_remote *remote,
 526     struct simap *usage)
 527 {
 528     struct ovsdb_jsonrpc_session *s;
 529
 530     LIST_FOR_EACH (s, node, &remote->sessions) {
 531         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 532     }
 533 }
 534
 535 static void
 536 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 537 {
 538     struct ovsdb_jsonrpc_session *s, *next;
 539
 540     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 541         ovsdb_jsonrpc_session_close(s);
 542     }
 543 }
 544
 545 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 546  * reconnect. */
 547 static void
 548 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 549 {
 550     struct ovsdb_jsonrpc_session *s, *next;
 551
 552     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 553         jsonrpc_session_force_reconnect(s->js);
 554         if (!jsonrpc_session_is_alive(s->js)) {
 555             ovsdb_jsonrpc_session_close(s);
 556         }
 557     }
 558 }
 559
 560 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 561  * 'options'. */
 562 static void
 563 ovsdb_jsonrpc_session_set_all_options(
 564     struct ovsdb_jsonrpc_remote *remote,
 565     const struct ovsdb_jsonrpc_options *options)
 566 {
 567     struct ovsdb_jsonrpc_session *s;
 568
 569     if (remote->listener) {
 570         int error;
 571
 572         error = pstream_set_dscp(remote->listener, options->dscp);
 573         if (error) {
 574             VLOG_ERR("%s: set_dscp failed %s",
 575                      pstream_get_name(remote->listener), strerror(error));
 576         } else {
 577             remote->dscp = options->dscp;
 578         }
 579         /*
 580          * XXX race window between setting dscp to listening socket
 581          * and accepting socket. Accepted socket may have old dscp value.
 582          * Ignore this race window for now.
 583          */
 584     }
 585     LIST_FOR_EACH (s, node, &remote->sessions) {
 586         ovsdb_jsonrpc_session_set_options(s, options);
 587     }
 588 }
 589
 590 static bool
 591 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
 592                                  struct ovsdb_jsonrpc_remote_status *status)
 593 {
 594     const struct ovsdb_jsonrpc_session *s;
 595     const struct jsonrpc_session *js;
 596     struct ovsdb_lock_waiter *waiter;
 597     struct reconnect_stats rstats;
 598     struct ds locks_held, locks_waiting, locks_lost;
 599
 600     if (list_is_empty(&remote->sessions)) {
 601         return false;
 602     }
 603     s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
 604     js = s->js;
 605
 606     status->is_connected = jsonrpc_session_is_connected(js);
 607     status->last_error = jsonrpc_session_get_status(js);
 608
 609     jsonrpc_session_get_reconnect_stats(js, &rstats);
 610     status->state = rstats.state;
 611     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 612         ? UINT_MAX : rstats.msec_since_connect / 1000;
 613     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 614         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 615
 616     ds_init(&locks_held);
 617     ds_init(&locks_waiting);
 618     ds_init(&locks_lost);
 619     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 620         struct ds *string;
 621
 622         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 623                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 624                   : &locks_lost);
 625         if (string->length) {
 626             ds_put_char(string, ' ');
 627         }
 628         ds_put_cstr(string, waiter->lock_name);
 629     }
 630     status->locks_held = ds_steal_cstr(&locks_held);
 631     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 632     status->locks_lost = ds_steal_cstr(&locks_lost);
 633
 634     status->n_connections = list_size(&remote->sessions);
 635
 636     return true;
 637 }
 638
 639 /* Examines 'request' to determine the database to which it relates, and then
 640  * searches 's' to find that database:
 641  *
 642  *    - If successful, returns the database and sets '*replyp' to NULL.
 643  *
 644  *    - If no such database exists, returns NULL and sets '*replyp' to an
 645  *      appropriate JSON-RPC error reply, owned by the caller. */
 646 static struct ovsdb *
 647 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 648                         const struct jsonrpc_msg *request,
 649                         struct jsonrpc_msg **replyp)
 650 {
 651     struct json_array *params;
 652     struct ovsdb_error *error;
 653     const char *db_name;
 654     struct ovsdb *db;
 655
 656     params = json_array(request->params);
 657     if (!params->n || params->elems[0]->type != JSON_STRING) {
 658         error = ovsdb_syntax_error(
 659             request->params, NULL,
 660             "%s request params must begin with <db-name>", request->method);
 661         goto error;
 662     }
 663
 664     db_name = params->elems[0]->u.string;
 665     db = shash_find_data(&s->up.server->dbs, db_name);
 666     if (!db) {
 667         error = ovsdb_syntax_error(
 668             request->params, "unknown database",
 669             "%s request specifies unknown database %s",
 670             request->method, db_name);
 671         goto error;
 672     }
 673
 674     *replyp = NULL;
 675     return db;
 676
 677 error:
 678     *replyp = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 679     ovsdb_error_destroy(error);
 680     return NULL;
 681 }
 682
 683 static struct ovsdb_error *
 684 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 685                                       const char **lock_namep)
 686 {
 687     const struct json_array *params;
 688
 689     params = json_array(request->params);
 690     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 691         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 692         *lock_namep = NULL;
 693         return ovsdb_syntax_error(request->params, NULL,
 694                                   "%s request params must be <id>",
 695                                   request->method);
 696     }
 697
 698     *lock_namep = json_string(params->elems[0]);
 699     return NULL;
 700 }
 701
 702 static void
 703 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 704                              const char *lock_name,
 705                              const char *method)
 706 {
 707     struct ovsdb_jsonrpc_session *s;
 708     struct json *params;
 709
 710     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 711     params = json_array_create_1(json_string_create(lock_name));
 712     jsonrpc_session_send(s->js, jsonrpc_create_notify(method, params));
 713 }
 714
 715 static struct jsonrpc_msg *
 716 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 717                            struct jsonrpc_msg *request,
 718                            enum ovsdb_lock_mode mode)
 719 {
 720     struct ovsdb_lock_waiter *waiter;
 721     struct jsonrpc_msg *reply;
 722     struct ovsdb_error *error;
 723     struct ovsdb_session *victim;
 724     const char *lock_name;
 725     struct json *result;
 726
 727     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 728     if (error) {
 729         goto error;
 730     }
 731
 732     /* Report error if this session has issued a "lock" or "steal" without a
 733      * matching "unlock" for this lock. */
 734     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 735     if (waiter) {
 736         error = ovsdb_syntax_error(
 737             request->params, NULL,
 738             "must issue \"unlock\" before new \"%s\"", request->method);
 739         goto error;
 740     }
 741
 742     /* Get the lock, add us as a waiter. */
 743     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 744                                &victim);
 745     if (victim) {
 746         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 747     }
 748
 749     result = json_object_create();
 750     json_object_put(result, "locked",
 751                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 752
 753     return jsonrpc_create_reply(result, request->id);
 754
 755 error:
 756     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 757     ovsdb_error_destroy(error);
 758     return reply;
 759 }
 760
 761 static void
 762 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 763 {
 764     struct ovsdb_lock_waiter *waiter, *next;
 765
 766     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 767         ovsdb_jsonrpc_session_unlock__(waiter);
 768     }
 769 }
 770
 771 static void
 772 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 773 {
 774     struct ovsdb_lock *lock = waiter->lock;
 775
 776     if (lock) {
 777         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 778         if (new_owner) {
 779             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 780         } else {
 781             /* ovsdb_server_lock() might have freed 'lock'. */
 782         }
 783     }
 784
 785     ovsdb_lock_waiter_destroy(waiter);
 786 }
 787
 788 static struct jsonrpc_msg *
 789 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 790                              struct jsonrpc_msg *request)
 791 {
 792     struct ovsdb_lock_waiter *waiter;
 793     struct jsonrpc_msg *reply;
 794     struct ovsdb_error *error;
 795     const char *lock_name;
 796
 797     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 798     if (error) {
 799         goto error;
 800     }
 801
 802     /* Report error if this session has not issued a "lock" or "steal" for this
 803      * lock. */
 804     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 805     if (!waiter) {
 806         error = ovsdb_syntax_error(
 807             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 808         goto error;
 809     }
 810
 811     ovsdb_jsonrpc_session_unlock__(waiter);
 812
 813     return jsonrpc_create_reply(json_object_create(), request->id);
 814
 815 error:
 816     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 817     ovsdb_error_destroy(error);
 818     return reply;
 819 }
 820
 821 static struct jsonrpc_msg *
 822 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 823                     struct jsonrpc_msg *request)
 824 {
 825     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 826     request->id = NULL;
 827     request->params = NULL;
 828     jsonrpc_msg_destroy(request);
 829     return NULL;
 830 }
 831
 832 static void
 833 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 834                                   struct jsonrpc_msg *request)
 835 {
 836     struct jsonrpc_msg *reply;
 837
 838     if (!strcmp(request->method, "transact")) {
 839         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 840         if (!reply) {
 841             reply = execute_transaction(s, db, request);
 842         }
 843     } else if (!strcmp(request->method, "monitor")) {
 844         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 845         if (!reply) {
 846             reply = jsonrpc_create_reply(
 847                 ovsdb_jsonrpc_monitor_create(s, db, request->params),
 848                 request->id);
 849         }
 850     } else if (!strcmp(request->method, "monitor_cancel")) {
 851         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 852                                              request->id);
 853     } else if (!strcmp(request->method, "get_schema")) {
 854         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 855         if (!reply) {
 856             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 857                                          request->id);
 858         }
 859     } else if (!strcmp(request->method, "list_dbs")) {
 860         size_t n_dbs = shash_count(&s->up.server->dbs);
 861         struct shash_node *node;
 862         struct json **dbs;
 863         size_t i;
 864
 865         dbs = xmalloc(n_dbs * sizeof *dbs);
 866         i = 0;
 867         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 868             dbs[i++] = json_string_create(node->name);
 869         }
 870         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 871                                      request->id);
 872     } else if (!strcmp(request->method, "lock")) {
 873         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 874     } else if (!strcmp(request->method, "steal")) {
 875         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 876     } else if (!strcmp(request->method, "unlock")) {
 877         reply = ovsdb_jsonrpc_session_unlock(s, request);
 878     } else if (!strcmp(request->method, "echo")) {
 879         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 880     } else {
 881         reply = jsonrpc_create_error(json_string_create("unknown method"),
 882                                      request->id);
 883     }
 884
 885     if (reply) {
 886         jsonrpc_msg_destroy(request);
 887         jsonrpc_session_send(s->js, reply);
 888     }
 889 }
 890
 891 static void
 892 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 893 {
 894     if (json_array(request->params)->n == 1) {
 895         struct ovsdb_jsonrpc_trigger *t;
 896         struct json *id;
 897
 898         id = request->params->u.array.elems[0];
 899         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 900         if (t) {
 901             ovsdb_jsonrpc_trigger_complete(t);
 902         }
 903     }
 904 }
 905
 906 static void
 907 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 908                                  struct jsonrpc_msg *request)
 909 {
 910     if (!strcmp(request->method, "cancel")) {
 911         execute_cancel(s, request);
 912     }
 913     jsonrpc_msg_destroy(request);
 914 }
 915 \f
 916 /* JSON-RPC database server triggers.
 917  *
 918  * (Every transaction is treated as a trigger even if it doesn't actually have
 919  * any "wait" operations.) */
 920
 921 struct ovsdb_jsonrpc_trigger {
 922     struct ovsdb_trigger trigger;
 923     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 924     struct json *id;
 925 };
 926
 927 static void
 928 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 929                              struct json *id, struct json *params)
 930 {
 931     struct ovsdb_jsonrpc_trigger *t;
 932     size_t hash;
 933
 934     /* Check for duplicate ID. */
 935     hash = json_hash(id, 0);
 936     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 937     if (t) {
 938         struct jsonrpc_msg *msg;
 939
 940         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 941                                    id);
 942         jsonrpc_session_send(s->js, msg);
 943         json_destroy(id);
 944         json_destroy(params);
 945         return;
 946     }
 947
 948     /* Insert into trigger table. */
 949     t = xmalloc(sizeof *t);
 950     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 951     t->id = id;
 952     hmap_insert(&s->triggers, &t->hmap_node, hash);
 953
 954     /* Complete early if possible. */
 955     if (ovsdb_trigger_is_complete(&t->trigger)) {
 956         ovsdb_jsonrpc_trigger_complete(t);
 957     }
 958 }
 959
 960 static struct ovsdb_jsonrpc_trigger *
 961 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 962                            const struct json *id, size_t hash)
 963 {
 964     struct ovsdb_jsonrpc_trigger *t;
 965
 966     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
 967         if (json_equal(t->id, id)) {
 968             return t;
 969         }
 970     }
 971
 972     return NULL;
 973 }
 974
 975 static void
 976 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 977 {
 978     struct ovsdb_jsonrpc_session *s;
 979
 980     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 981
 982     if (jsonrpc_session_is_connected(s->js)) {
 983         struct jsonrpc_msg *reply;
 984         struct json *result;
 985
 986         result = ovsdb_trigger_steal_result(&t->trigger);
 987         if (result) {
 988             reply = jsonrpc_create_reply(result, t->id);
 989         } else {
 990             reply = jsonrpc_create_error(json_string_create("canceled"),
 991                                          t->id);
 992         }
 993         jsonrpc_session_send(s->js, reply);
 994     }
 995
 996     json_destroy(t->id);
 997     ovsdb_trigger_destroy(&t->trigger);
 998     hmap_remove(&s->triggers, &t->hmap_node);
 999     free(t);
1000 }
1001
1002 static void
1003 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
1004 {
1005     struct ovsdb_jsonrpc_trigger *t, *next;
1006     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
1007         ovsdb_jsonrpc_trigger_complete(t);
1008     }
1009 }
1010
1011 static void
1012 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
1013 {
1014     while (!list_is_empty(&s->up.completions)) {
1015         struct ovsdb_jsonrpc_trigger *t
1016             = CONTAINER_OF(s->up.completions.next,
1017                            struct ovsdb_jsonrpc_trigger, trigger.node);
1018         ovsdb_jsonrpc_trigger_complete(t);
1019     }
1020 }
1021 \f
1022 /* JSON-RPC database table monitors. */
1023
1024 enum ovsdb_jsonrpc_monitor_selection {
1025     OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
1026     OJMS_INSERT = 1 << 1,       /* New rows. */
1027     OJMS_DELETE = 1 << 2,       /* Deleted rows. */
1028     OJMS_MODIFY = 1 << 3        /* Modified rows. */
1029 };
1030
1031 /* A particular column being monitored. */
1032 struct ovsdb_jsonrpc_monitor_column {
1033     const struct ovsdb_column *column;
1034     enum ovsdb_jsonrpc_monitor_selection select;
1035 };
1036
1037 /* A particular table being monitored. */
1038 struct ovsdb_jsonrpc_monitor_table {
1039     const struct ovsdb_table *table;
1040
1041     /* This is the union (bitwise-OR) of the 'select' values in all of the
1042      * members of 'columns' below. */
1043     enum ovsdb_jsonrpc_monitor_selection select;
1044
1045     /* Columns being monitored. */
1046     struct ovsdb_jsonrpc_monitor_column *columns;
1047     size_t n_columns;
1048 };
1049
1050 /* A collection of tables being monitored. */
1051 struct ovsdb_jsonrpc_monitor {
1052     struct ovsdb_replica replica;
1053     struct ovsdb_jsonrpc_session *session;
1054     struct ovsdb *db;
1055     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1056
1057     struct json *monitor_id;
1058     struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
1059 };
1060
1061 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
1062
1063 struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
1064     struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
1065 static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
1066 static struct json *ovsdb_jsonrpc_monitor_get_initial(
1067     const struct ovsdb_jsonrpc_monitor *);
1068 static size_t ovsdb_jsonrpc_monitor_json_length(
1069     const struct ovsdb_jsonrpc_monitor *);
1070
1071 static bool
1072 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1073 {
1074     const struct json *json;
1075
1076     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1077     return json ? json_boolean(json) : default_value;
1078 }
1079
1080 struct ovsdb_jsonrpc_monitor *
1081 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1082                            const struct json *monitor_id)
1083 {
1084     struct ovsdb_jsonrpc_monitor *m;
1085
1086     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1087         if (json_equal(m->monitor_id, monitor_id)) {
1088             return m;
1089         }
1090     }
1091
1092     return NULL;
1093 }
1094
1095 static void
1096 ovsdb_jsonrpc_add_monitor_column(struct ovsdb_jsonrpc_monitor_table *mt,
1097                                  const struct ovsdb_column *column,
1098                                  enum ovsdb_jsonrpc_monitor_selection select,
1099                                  size_t *allocated_columns)
1100 {
1101     struct ovsdb_jsonrpc_monitor_column *c;
1102
1103     if (mt->n_columns >= *allocated_columns) {
1104         mt->columns = x2nrealloc(mt->columns, allocated_columns,
1105                                  sizeof *mt->columns);
1106     }
1107
1108     c = &mt->columns[mt->n_columns++];
1109     c->column = column;
1110     c->select = select;
1111 }
1112
1113 static int
1114 compare_ovsdb_jsonrpc_monitor_column(const void *a_, const void *b_)
1115 {
1116     const struct ovsdb_jsonrpc_monitor_column *a = a_;
1117     const struct ovsdb_jsonrpc_monitor_column *b = b_;
1118
1119     return a->column < b->column ? -1 : a->column > b->column;
1120 }
1121
1122 static struct ovsdb_error * WARN_UNUSED_RESULT
1123 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
1124                                     const struct json *monitor_request,
1125                                     size_t *allocated_columns)
1126 {
1127     const struct ovsdb_table_schema *ts = mt->table->schema;
1128     enum ovsdb_jsonrpc_monitor_selection select;
1129     const struct json *columns, *select_json;
1130     struct ovsdb_parser parser;
1131     struct ovsdb_error *error;
1132
1133     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1134     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1135     select_json = ovsdb_parser_member(&parser, "select",
1136                                       OP_OBJECT | OP_OPTIONAL);
1137     error = ovsdb_parser_finish(&parser);
1138     if (error) {
1139         return error;
1140     }
1141
1142     if (select_json) {
1143         select = 0;
1144         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1145         if (parse_bool(&parser, "initial", true)) {
1146             select |= OJMS_INITIAL;
1147         }
1148         if (parse_bool(&parser, "insert", true)) {
1149             select |= OJMS_INSERT;
1150         }
1151         if (parse_bool(&parser, "delete", true)) {
1152             select |= OJMS_DELETE;
1153         }
1154         if (parse_bool(&parser, "modify", true)) {
1155             select |= OJMS_MODIFY;
1156         }
1157         error = ovsdb_parser_finish(&parser);
1158         if (error) {
1159             return error;
1160         }
1161     } else {
1162         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1163     }
1164     mt->select |= select;
1165
1166     if (columns) {
1167         size_t i;
1168
1169         if (columns->type != JSON_ARRAY) {
1170             return ovsdb_syntax_error(columns, NULL,
1171                                       "array of column names expected");
1172         }
1173
1174         for (i = 0; i < columns->u.array.n; i++) {
1175             const struct ovsdb_column *column;
1176             const char *s;
1177
1178             if (columns->u.array.elems[i]->type != JSON_STRING) {
1179                 return ovsdb_syntax_error(columns, NULL,
1180                                           "array of column names expected");
1181             }
1182
1183             s = columns->u.array.elems[i]->u.string;
1184             column = shash_find_data(&mt->table->schema->columns, s);
1185             if (!column) {
1186                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1187                                           "column name", s);
1188             }
1189             ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1190                                              allocated_columns);
1191         }
1192     } else {
1193         struct shash_node *node;
1194
1195         SHASH_FOR_EACH (node, &ts->columns) {
1196             const struct ovsdb_column *column = node->data;
1197             if (column->index != OVSDB_COL_UUID) {
1198                 ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1199                                                  allocated_columns);
1200             }
1201         }
1202     }
1203
1204     return NULL;
1205 }
1206
1207 static struct json *
1208 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1209                              struct json *params)
1210 {
1211     struct ovsdb_jsonrpc_monitor *m = NULL;
1212     struct json *monitor_id, *monitor_requests;
1213     struct ovsdb_error *error = NULL;
1214     struct shash_node *node;
1215     struct json *json;
1216
1217     if (json_array(params)->n != 3) {
1218         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1219         goto error;
1220     }
1221     monitor_id = params->u.array.elems[1];
1222     monitor_requests = params->u.array.elems[2];
1223     if (monitor_requests->type != JSON_OBJECT) {
1224         error = ovsdb_syntax_error(monitor_requests, NULL,
1225                                    "monitor-requests must be object");
1226         goto error;
1227     }
1228
1229     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1230         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1231         goto error;
1232     }
1233
1234     m = xzalloc(sizeof *m);
1235     ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
1236     ovsdb_add_replica(db, &m->replica);
1237     m->session = s;
1238     m->db = db;
1239     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1240     m->monitor_id = json_clone(monitor_id);
1241     shash_init(&m->tables);
1242
1243     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1244         const struct ovsdb_table *table;
1245         struct ovsdb_jsonrpc_monitor_table *mt;
1246         size_t allocated_columns;
1247         const struct json *mr_value;
1248         size_t i;
1249
1250         table = ovsdb_get_table(m->db, node->name);
1251         if (!table) {
1252             error = ovsdb_syntax_error(NULL, NULL,
1253                                        "no table named %s", node->name);
1254             goto error;
1255         }
1256
1257         mt = xzalloc(sizeof *mt);
1258         mt->table = table;
1259         shash_add(&m->tables, table->schema->name, mt);
1260
1261         /* Parse columns. */
1262         mr_value = node->data;
1263         allocated_columns = 0;
1264         if (mr_value->type == JSON_ARRAY) {
1265             const struct json_array *array = &mr_value->u.array;
1266
1267             for (i = 0; i < array->n; i++) {
1268                 error = ovsdb_jsonrpc_parse_monitor_request(
1269                     mt, array->elems[i], &allocated_columns);
1270                 if (error) {
1271                     goto error;
1272                 }
1273             }
1274         } else {
1275             error = ovsdb_jsonrpc_parse_monitor_request(
1276                 mt, mr_value, &allocated_columns);
1277             if (error) {
1278                 goto error;
1279             }
1280         }
1281
1282         /* Check for duplicate columns. */
1283         qsort(mt->columns, mt->n_columns, sizeof *mt->columns,
1284               compare_ovsdb_jsonrpc_monitor_column);
1285         for (i = 1; i < mt->n_columns; i++) {
1286             if (mt->columns[i].column == mt->columns[i - 1].column) {
1287                 error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1288                                            "mentioned more than once",
1289                                            mt->columns[i].column->name);
1290                 goto error;
1291             }
1292         }
1293     }
1294
1295     return ovsdb_jsonrpc_monitor_get_initial(m);
1296
1297 error:
1298     if (m) {
1299         ovsdb_remove_replica(m->db, &m->replica);
1300     }
1301
1302     json = ovsdb_error_to_json(error);
1303     ovsdb_error_destroy(error);
1304     return json;
1305 }
1306
1307 static struct jsonrpc_msg *
1308 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1309                              struct json_array *params,
1310                              const struct json *request_id)
1311 {
1312     if (params->n != 1) {
1313         return jsonrpc_create_error(json_string_create("invalid parameters"),
1314                                     request_id);
1315     } else {
1316         struct ovsdb_jsonrpc_monitor *m;
1317
1318         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1319         if (!m) {
1320             return jsonrpc_create_error(json_string_create("unknown monitor"),
1321                                         request_id);
1322         } else {
1323             ovsdb_remove_replica(m->db, &m->replica);
1324             return jsonrpc_create_reply(json_object_create(), request_id);
1325         }
1326     }
1327 }
1328
1329 static void
1330 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1331 {
1332     struct ovsdb_jsonrpc_monitor *m, *next;
1333
1334     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1335         ovsdb_remove_replica(m->db, &m->replica);
1336     }
1337 }
1338
1339 /* Returns an overestimate of the number of bytes of JSON data required to
1340  * report the current contents of the database over all the monitors currently
1341  * configured in 's'.  */
1342 static size_t
1343 ovsdb_jsonrpc_monitor_json_length_all(struct ovsdb_jsonrpc_session *s)
1344 {
1345     struct ovsdb_jsonrpc_monitor *m;
1346     size_t length;
1347
1348     length = 0;
1349     HMAP_FOR_EACH (m, node, &s->monitors) {
1350         length += ovsdb_jsonrpc_monitor_json_length(m);
1351     }
1352     return length;
1353 }
1354
1355 static struct ovsdb_jsonrpc_monitor *
1356 ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
1357 {
1358     ovs_assert(replica->class == &ovsdb_jsonrpc_replica_class);
1359     return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
1360 }
1361
1362 struct ovsdb_jsonrpc_monitor_aux {
1363     bool initial;               /* Sending initial contents of table? */
1364     const struct ovsdb_jsonrpc_monitor *monitor;
1365     struct json *json;          /* JSON for the whole transaction. */
1366
1367     /* Current table.  */
1368     struct ovsdb_jsonrpc_monitor_table *mt;
1369     struct json *table_json;    /* JSON for table's transaction. */
1370 };
1371
1372 static bool
1373 any_reportable_change(const struct ovsdb_jsonrpc_monitor_table *mt,
1374                       const unsigned long int *changed)
1375 {
1376     size_t i;
1377
1378     for (i = 0; i < mt->n_columns; i++) {
1379         const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1380         unsigned int idx = c->column->index;
1381
1382         if (c->select & OJMS_MODIFY && bitmap_is_set(changed, idx)) {
1383             return true;
1384         }
1385     }
1386
1387     return false;
1388 }
1389
1390 static bool
1391 ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
1392                                 const struct ovsdb_row *new,
1393                                 const unsigned long int *changed,
1394                                 void *aux_)
1395 {
1396     struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
1397     const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
1398     struct ovsdb_table *table = new ? new->table : old->table;
1399     enum ovsdb_jsonrpc_monitor_selection type;
1400     struct json *old_json, *new_json;
1401     struct json *row_json;
1402     char uuid[UUID_LEN + 1];
1403     size_t i;
1404
1405     if (!aux->mt || table != aux->mt->table) {
1406         aux->mt = shash_find_data(&m->tables, table->schema->name);
1407         aux->table_json = NULL;
1408         if (!aux->mt) {
1409             /* We don't care about rows in this table at all.  Tell the caller
1410              * to skip it.  */
1411             return false;
1412         }
1413     }
1414
1415     type = (aux->initial ? OJMS_INITIAL
1416             : !old ? OJMS_INSERT
1417             : !new ? OJMS_DELETE
1418             : OJMS_MODIFY);
1419     if (!(aux->mt->select & type)) {
1420         /* We don't care about this type of change (but do want to be called
1421          * back for changes to other rows in the same table). */
1422         return true;
1423     }
1424
1425     if (type == OJMS_MODIFY && !any_reportable_change(aux->mt, changed)) {
1426         /* Nothing of interest changed. */
1427         return true;
1428     }
1429
1430     old_json = new_json = NULL;
1431     if (type & (OJMS_DELETE | OJMS_MODIFY)) {
1432         old_json = json_object_create();
1433     }
1434     if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1435         new_json = json_object_create();
1436     }
1437     for (i = 0; i < aux->mt->n_columns; i++) {
1438         const struct ovsdb_jsonrpc_monitor_column *c = &aux->mt->columns[i];
1439         const struct ovsdb_column *column = c->column;
1440         unsigned int idx = c->column->index;
1441
1442         if (!(type & c->select)) {
1443             /* We don't care about this type of change for this particular
1444              * column (but we will care about it for some other column). */
1445             continue;
1446         }
1447
1448         if ((type == OJMS_MODIFY && bitmap_is_set(changed, idx))
1449             || type == OJMS_DELETE) {
1450             json_object_put(old_json, column->name,
1451                             ovsdb_datum_to_json(&old->fields[idx],
1452                                                 &column->type));
1453         }
1454         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1455             json_object_put(new_json, column->name,
1456                             ovsdb_datum_to_json(&new->fields[idx],
1457                                                 &column->type));
1458         }
1459     }
1460
1461     /* Create JSON object for transaction overall. */
1462     if (!aux->json) {
1463         aux->json = json_object_create();
1464     }
1465
1466     /* Create JSON object for transaction on this table. */
1467     if (!aux->table_json) {
1468         aux->table_json = json_object_create();
1469         json_object_put(aux->json, aux->mt->table->schema->name,
1470                         aux->table_json);
1471     }
1472
1473     /* Create JSON object for transaction on this row. */
1474     row_json = json_object_create();
1475     if (old_json) {
1476         json_object_put(row_json, "old", old_json);
1477     }
1478     if (new_json) {
1479         json_object_put(row_json, "new", new_json);
1480     }
1481
1482     /* Add JSON row to JSON table. */
1483     snprintf(uuid, sizeof uuid,
1484              UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
1485     json_object_put(aux->table_json, uuid, row_json);
1486
1487     return true;
1488 }
1489
1490 /* Returns an overestimate of the number of bytes of JSON data required to
1491  * report the current contents of the database over monitor 'm'. */
1492 static size_t
1493 ovsdb_jsonrpc_monitor_json_length(const struct ovsdb_jsonrpc_monitor *m)
1494 {
1495     const struct shash_node *node;
1496     size_t length;
1497
1498     /* Top-level overhead of monitor JSON. */
1499     length = 256;
1500
1501     SHASH_FOR_EACH (node, &m->tables) {
1502         const struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1503         const struct ovsdb_table *table = mt->table;
1504         const struct ovsdb_row *row;
1505         size_t i;
1506
1507         /* Per-table JSON overhead: "<table>":{...}. */
1508         length += strlen(table->schema->name) + 32;
1509
1510         /* Per-row JSON overhead: ,"<uuid>":{"old":{...},"new":{...}} */
1511         length += hmap_count(&table->rows) * (UUID_LEN + 32);
1512
1513         /* Per-row, per-column JSON overhead: ,"<column>": */
1514         for (i = 0; i < mt->n_columns; i++) {
1515             const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1516             const struct ovsdb_column *column = c->column;
1517
1518             length += hmap_count(&table->rows) * (8 + strlen(column->name));
1519         }
1520
1521         /* Data. */
1522         HMAP_FOR_EACH (row, hmap_node, &table->rows) {
1523             for (i = 0; i < mt->n_columns; i++) {
1524                 const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1525                 const struct ovsdb_column *column = c->column;
1526
1527                 length += ovsdb_datum_json_length(&row->fields[column->index],
1528                                                   &column->type);
1529             }
1530         }
1531     }
1532
1533     return length;
1534 }
1535
1536 static void
1537 ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
1538                                const struct ovsdb_jsonrpc_monitor *m,
1539                                bool initial)
1540 {
1541     aux->initial = initial;
1542     aux->monitor = m;
1543     aux->json = NULL;
1544     aux->mt = NULL;
1545     aux->table_json = NULL;
1546 }
1547
1548 static struct ovsdb_error *
1549 ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
1550                              const struct ovsdb_txn *txn,
1551                              bool durable OVS_UNUSED)
1552 {
1553     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1554     struct ovsdb_jsonrpc_monitor_aux aux;
1555
1556     ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
1557     ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
1558     if (aux.json) {
1559         struct jsonrpc_msg *msg;
1560         struct json *params;
1561
1562         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
1563                                      aux.json);
1564         msg = jsonrpc_create_notify("update", params);
1565         jsonrpc_session_send(aux.monitor->session->js, msg);
1566     }
1567
1568     return NULL;
1569 }
1570
1571 static struct json *
1572 ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
1573 {
1574     struct ovsdb_jsonrpc_monitor_aux aux;
1575     struct shash_node *node;
1576
1577     ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
1578     SHASH_FOR_EACH (node, &m->tables) {
1579         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1580
1581         if (mt->select & OJMS_INITIAL) {
1582             struct ovsdb_row *row;
1583
1584             HMAP_FOR_EACH (row, hmap_node, &mt->table->rows) {
1585                 ovsdb_jsonrpc_monitor_change_cb(NULL, row, NULL, &aux);
1586             }
1587         }
1588     }
1589     return aux.json ? aux.json : json_object_create();
1590 }
1591
1592 static void
1593 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
1594 {
1595     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1596     struct shash_node *node;
1597
1598     json_destroy(m->monitor_id);
1599     SHASH_FOR_EACH (node, &m->tables) {
1600         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1601         free(mt->columns);
1602         free(mt);
1603     }
1604     shash_destroy(&m->tables);
1605     hmap_remove(&m->session->monitors, &m->node);
1606     free(m);
1607 }
1608
1609 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
1610     ovsdb_jsonrpc_monitor_commit,
1611     ovsdb_jsonrpc_monitor_destroy
1612 };