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     status->bound_port = (remote->listener
 601                           ? pstream_get_bound_port(remote->listener)
 602                           : htons(0));
 603
 604     if (list_is_empty(&remote->sessions)) {
 605         return false;
 606     }
 607     s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
 608     js = s->js;
 609
 610     status->is_connected = jsonrpc_session_is_connected(js);
 611     status->last_error = jsonrpc_session_get_status(js);
 612
 613     jsonrpc_session_get_reconnect_stats(js, &rstats);
 614     status->state = rstats.state;
 615     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 616         ? UINT_MAX : rstats.msec_since_connect / 1000;
 617     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 618         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 619
 620     ds_init(&locks_held);
 621     ds_init(&locks_waiting);
 622     ds_init(&locks_lost);
 623     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 624         struct ds *string;
 625
 626         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 627                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 628                   : &locks_lost);
 629         if (string->length) {
 630             ds_put_char(string, ' ');
 631         }
 632         ds_put_cstr(string, waiter->lock_name);
 633     }
 634     status->locks_held = ds_steal_cstr(&locks_held);
 635     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 636     status->locks_lost = ds_steal_cstr(&locks_lost);
 637
 638     status->n_connections = list_size(&remote->sessions);
 639
 640     return true;
 641 }
 642
 643 /* Examines 'request' to determine the database to which it relates, and then
 644  * searches 's' to find that database:
 645  *
 646  *    - If successful, returns the database and sets '*replyp' to NULL.
 647  *
 648  *    - If no such database exists, returns NULL and sets '*replyp' to an
 649  *      appropriate JSON-RPC error reply, owned by the caller. */
 650 static struct ovsdb *
 651 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 652                         const struct jsonrpc_msg *request,
 653                         struct jsonrpc_msg **replyp)
 654 {
 655     struct json_array *params;
 656     struct ovsdb_error *error;
 657     const char *db_name;
 658     struct ovsdb *db;
 659
 660     params = json_array(request->params);
 661     if (!params->n || params->elems[0]->type != JSON_STRING) {
 662         error = ovsdb_syntax_error(
 663             request->params, NULL,
 664             "%s request params must begin with <db-name>", request->method);
 665         goto error;
 666     }
 667
 668     db_name = params->elems[0]->u.string;
 669     db = shash_find_data(&s->up.server->dbs, db_name);
 670     if (!db) {
 671         error = ovsdb_syntax_error(
 672             request->params, "unknown database",
 673             "%s request specifies unknown database %s",
 674             request->method, db_name);
 675         goto error;
 676     }
 677
 678     *replyp = NULL;
 679     return db;
 680
 681 error:
 682     *replyp = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 683     ovsdb_error_destroy(error);
 684     return NULL;
 685 }
 686
 687 static struct ovsdb_error *
 688 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 689                                       const char **lock_namep)
 690 {
 691     const struct json_array *params;
 692
 693     params = json_array(request->params);
 694     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 695         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 696         *lock_namep = NULL;
 697         return ovsdb_syntax_error(request->params, NULL,
 698                                   "%s request params must be <id>",
 699                                   request->method);
 700     }
 701
 702     *lock_namep = json_string(params->elems[0]);
 703     return NULL;
 704 }
 705
 706 static void
 707 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 708                              const char *lock_name,
 709                              const char *method)
 710 {
 711     struct ovsdb_jsonrpc_session *s;
 712     struct json *params;
 713
 714     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 715     params = json_array_create_1(json_string_create(lock_name));
 716     jsonrpc_session_send(s->js, jsonrpc_create_notify(method, params));
 717 }
 718
 719 static struct jsonrpc_msg *
 720 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 721                            struct jsonrpc_msg *request,
 722                            enum ovsdb_lock_mode mode)
 723 {
 724     struct ovsdb_lock_waiter *waiter;
 725     struct jsonrpc_msg *reply;
 726     struct ovsdb_error *error;
 727     struct ovsdb_session *victim;
 728     const char *lock_name;
 729     struct json *result;
 730
 731     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 732     if (error) {
 733         goto error;
 734     }
 735
 736     /* Report error if this session has issued a "lock" or "steal" without a
 737      * matching "unlock" for this lock. */
 738     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 739     if (waiter) {
 740         error = ovsdb_syntax_error(
 741             request->params, NULL,
 742             "must issue \"unlock\" before new \"%s\"", request->method);
 743         goto error;
 744     }
 745
 746     /* Get the lock, add us as a waiter. */
 747     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 748                                &victim);
 749     if (victim) {
 750         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 751     }
 752
 753     result = json_object_create();
 754     json_object_put(result, "locked",
 755                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 756
 757     return jsonrpc_create_reply(result, request->id);
 758
 759 error:
 760     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 761     ovsdb_error_destroy(error);
 762     return reply;
 763 }
 764
 765 static void
 766 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 767 {
 768     struct ovsdb_lock_waiter *waiter, *next;
 769
 770     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 771         ovsdb_jsonrpc_session_unlock__(waiter);
 772     }
 773 }
 774
 775 static void
 776 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 777 {
 778     struct ovsdb_lock *lock = waiter->lock;
 779
 780     if (lock) {
 781         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 782         if (new_owner) {
 783             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 784         } else {
 785             /* ovsdb_server_lock() might have freed 'lock'. */
 786         }
 787     }
 788
 789     ovsdb_lock_waiter_destroy(waiter);
 790 }
 791
 792 static struct jsonrpc_msg *
 793 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 794                              struct jsonrpc_msg *request)
 795 {
 796     struct ovsdb_lock_waiter *waiter;
 797     struct jsonrpc_msg *reply;
 798     struct ovsdb_error *error;
 799     const char *lock_name;
 800
 801     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 802     if (error) {
 803         goto error;
 804     }
 805
 806     /* Report error if this session has not issued a "lock" or "steal" for this
 807      * lock. */
 808     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 809     if (!waiter) {
 810         error = ovsdb_syntax_error(
 811             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 812         goto error;
 813     }
 814
 815     ovsdb_jsonrpc_session_unlock__(waiter);
 816
 817     return jsonrpc_create_reply(json_object_create(), request->id);
 818
 819 error:
 820     reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id);
 821     ovsdb_error_destroy(error);
 822     return reply;
 823 }
 824
 825 static struct jsonrpc_msg *
 826 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 827                     struct jsonrpc_msg *request)
 828 {
 829     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 830     request->id = NULL;
 831     request->params = NULL;
 832     jsonrpc_msg_destroy(request);
 833     return NULL;
 834 }
 835
 836 static void
 837 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 838                                   struct jsonrpc_msg *request)
 839 {
 840     struct jsonrpc_msg *reply;
 841
 842     if (!strcmp(request->method, "transact")) {
 843         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 844         if (!reply) {
 845             reply = execute_transaction(s, db, request);
 846         }
 847     } else if (!strcmp(request->method, "monitor")) {
 848         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 849         if (!reply) {
 850             reply = jsonrpc_create_reply(
 851                 ovsdb_jsonrpc_monitor_create(s, db, request->params),
 852                 request->id);
 853         }
 854     } else if (!strcmp(request->method, "monitor_cancel")) {
 855         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 856                                              request->id);
 857     } else if (!strcmp(request->method, "get_schema")) {
 858         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 859         if (!reply) {
 860             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 861                                          request->id);
 862         }
 863     } else if (!strcmp(request->method, "list_dbs")) {
 864         size_t n_dbs = shash_count(&s->up.server->dbs);
 865         struct shash_node *node;
 866         struct json **dbs;
 867         size_t i;
 868
 869         dbs = xmalloc(n_dbs * sizeof *dbs);
 870         i = 0;
 871         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 872             dbs[i++] = json_string_create(node->name);
 873         }
 874         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 875                                      request->id);
 876     } else if (!strcmp(request->method, "lock")) {
 877         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 878     } else if (!strcmp(request->method, "steal")) {
 879         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 880     } else if (!strcmp(request->method, "unlock")) {
 881         reply = ovsdb_jsonrpc_session_unlock(s, request);
 882     } else if (!strcmp(request->method, "echo")) {
 883         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 884     } else {
 885         reply = jsonrpc_create_error(json_string_create("unknown method"),
 886                                      request->id);
 887     }
 888
 889     if (reply) {
 890         jsonrpc_msg_destroy(request);
 891         jsonrpc_session_send(s->js, reply);
 892     }
 893 }
 894
 895 static void
 896 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 897 {
 898     if (json_array(request->params)->n == 1) {
 899         struct ovsdb_jsonrpc_trigger *t;
 900         struct json *id;
 901
 902         id = request->params->u.array.elems[0];
 903         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 904         if (t) {
 905             ovsdb_jsonrpc_trigger_complete(t);
 906         }
 907     }
 908 }
 909
 910 static void
 911 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 912                                  struct jsonrpc_msg *request)
 913 {
 914     if (!strcmp(request->method, "cancel")) {
 915         execute_cancel(s, request);
 916     }
 917     jsonrpc_msg_destroy(request);
 918 }
 919 \f
 920 /* JSON-RPC database server triggers.
 921  *
 922  * (Every transaction is treated as a trigger even if it doesn't actually have
 923  * any "wait" operations.) */
 924
 925 struct ovsdb_jsonrpc_trigger {
 926     struct ovsdb_trigger trigger;
 927     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 928     struct json *id;
 929 };
 930
 931 static void
 932 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 933                              struct json *id, struct json *params)
 934 {
 935     struct ovsdb_jsonrpc_trigger *t;
 936     size_t hash;
 937
 938     /* Check for duplicate ID. */
 939     hash = json_hash(id, 0);
 940     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 941     if (t) {
 942         struct jsonrpc_msg *msg;
 943
 944         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 945                                    id);
 946         jsonrpc_session_send(s->js, msg);
 947         json_destroy(id);
 948         json_destroy(params);
 949         return;
 950     }
 951
 952     /* Insert into trigger table. */
 953     t = xmalloc(sizeof *t);
 954     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 955     t->id = id;
 956     hmap_insert(&s->triggers, &t->hmap_node, hash);
 957
 958     /* Complete early if possible. */
 959     if (ovsdb_trigger_is_complete(&t->trigger)) {
 960         ovsdb_jsonrpc_trigger_complete(t);
 961     }
 962 }
 963
 964 static struct ovsdb_jsonrpc_trigger *
 965 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 966                            const struct json *id, size_t hash)
 967 {
 968     struct ovsdb_jsonrpc_trigger *t;
 969
 970     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
 971         if (json_equal(t->id, id)) {
 972             return t;
 973         }
 974     }
 975
 976     return NULL;
 977 }
 978
 979 static void
 980 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 981 {
 982     struct ovsdb_jsonrpc_session *s;
 983
 984     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 985
 986     if (jsonrpc_session_is_connected(s->js)) {
 987         struct jsonrpc_msg *reply;
 988         struct json *result;
 989
 990         result = ovsdb_trigger_steal_result(&t->trigger);
 991         if (result) {
 992             reply = jsonrpc_create_reply(result, t->id);
 993         } else {
 994             reply = jsonrpc_create_error(json_string_create("canceled"),
 995                                          t->id);
 996         }
 997         jsonrpc_session_send(s->js, reply);
 998     }
 999
1000     json_destroy(t->id);
1001     ovsdb_trigger_destroy(&t->trigger);
1002     hmap_remove(&s->triggers, &t->hmap_node);
1003     free(t);
1004 }
1005
1006 static void
1007 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
1008 {
1009     struct ovsdb_jsonrpc_trigger *t, *next;
1010     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
1011         ovsdb_jsonrpc_trigger_complete(t);
1012     }
1013 }
1014
1015 static void
1016 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
1017 {
1018     while (!list_is_empty(&s->up.completions)) {
1019         struct ovsdb_jsonrpc_trigger *t
1020             = CONTAINER_OF(s->up.completions.next,
1021                            struct ovsdb_jsonrpc_trigger, trigger.node);
1022         ovsdb_jsonrpc_trigger_complete(t);
1023     }
1024 }
1025 \f
1026 /* JSON-RPC database table monitors. */
1027
1028 enum ovsdb_jsonrpc_monitor_selection {
1029     OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
1030     OJMS_INSERT = 1 << 1,       /* New rows. */
1031     OJMS_DELETE = 1 << 2,       /* Deleted rows. */
1032     OJMS_MODIFY = 1 << 3        /* Modified rows. */
1033 };
1034
1035 /* A particular column being monitored. */
1036 struct ovsdb_jsonrpc_monitor_column {
1037     const struct ovsdb_column *column;
1038     enum ovsdb_jsonrpc_monitor_selection select;
1039 };
1040
1041 /* A particular table being monitored. */
1042 struct ovsdb_jsonrpc_monitor_table {
1043     const struct ovsdb_table *table;
1044
1045     /* This is the union (bitwise-OR) of the 'select' values in all of the
1046      * members of 'columns' below. */
1047     enum ovsdb_jsonrpc_monitor_selection select;
1048
1049     /* Columns being monitored. */
1050     struct ovsdb_jsonrpc_monitor_column *columns;
1051     size_t n_columns;
1052 };
1053
1054 /* A collection of tables being monitored. */
1055 struct ovsdb_jsonrpc_monitor {
1056     struct ovsdb_replica replica;
1057     struct ovsdb_jsonrpc_session *session;
1058     struct ovsdb *db;
1059     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1060
1061     struct json *monitor_id;
1062     struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
1063 };
1064
1065 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
1066
1067 struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
1068     struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
1069 static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
1070 static struct json *ovsdb_jsonrpc_monitor_get_initial(
1071     const struct ovsdb_jsonrpc_monitor *);
1072 static size_t ovsdb_jsonrpc_monitor_json_length(
1073     const struct ovsdb_jsonrpc_monitor *);
1074
1075 static bool
1076 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1077 {
1078     const struct json *json;
1079
1080     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1081     return json ? json_boolean(json) : default_value;
1082 }
1083
1084 struct ovsdb_jsonrpc_monitor *
1085 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1086                            const struct json *monitor_id)
1087 {
1088     struct ovsdb_jsonrpc_monitor *m;
1089
1090     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1091         if (json_equal(m->monitor_id, monitor_id)) {
1092             return m;
1093         }
1094     }
1095
1096     return NULL;
1097 }
1098
1099 static void
1100 ovsdb_jsonrpc_add_monitor_column(struct ovsdb_jsonrpc_monitor_table *mt,
1101                                  const struct ovsdb_column *column,
1102                                  enum ovsdb_jsonrpc_monitor_selection select,
1103                                  size_t *allocated_columns)
1104 {
1105     struct ovsdb_jsonrpc_monitor_column *c;
1106
1107     if (mt->n_columns >= *allocated_columns) {
1108         mt->columns = x2nrealloc(mt->columns, allocated_columns,
1109                                  sizeof *mt->columns);
1110     }
1111
1112     c = &mt->columns[mt->n_columns++];
1113     c->column = column;
1114     c->select = select;
1115 }
1116
1117 static int
1118 compare_ovsdb_jsonrpc_monitor_column(const void *a_, const void *b_)
1119 {
1120     const struct ovsdb_jsonrpc_monitor_column *a = a_;
1121     const struct ovsdb_jsonrpc_monitor_column *b = b_;
1122
1123     return a->column < b->column ? -1 : a->column > b->column;
1124 }
1125
1126 static struct ovsdb_error * WARN_UNUSED_RESULT
1127 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt,
1128                                     const struct json *monitor_request,
1129                                     size_t *allocated_columns)
1130 {
1131     const struct ovsdb_table_schema *ts = mt->table->schema;
1132     enum ovsdb_jsonrpc_monitor_selection select;
1133     const struct json *columns, *select_json;
1134     struct ovsdb_parser parser;
1135     struct ovsdb_error *error;
1136
1137     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1138     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1139     select_json = ovsdb_parser_member(&parser, "select",
1140                                       OP_OBJECT | OP_OPTIONAL);
1141     error = ovsdb_parser_finish(&parser);
1142     if (error) {
1143         return error;
1144     }
1145
1146     if (select_json) {
1147         select = 0;
1148         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1149         if (parse_bool(&parser, "initial", true)) {
1150             select |= OJMS_INITIAL;
1151         }
1152         if (parse_bool(&parser, "insert", true)) {
1153             select |= OJMS_INSERT;
1154         }
1155         if (parse_bool(&parser, "delete", true)) {
1156             select |= OJMS_DELETE;
1157         }
1158         if (parse_bool(&parser, "modify", true)) {
1159             select |= OJMS_MODIFY;
1160         }
1161         error = ovsdb_parser_finish(&parser);
1162         if (error) {
1163             return error;
1164         }
1165     } else {
1166         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1167     }
1168     mt->select |= select;
1169
1170     if (columns) {
1171         size_t i;
1172
1173         if (columns->type != JSON_ARRAY) {
1174             return ovsdb_syntax_error(columns, NULL,
1175                                       "array of column names expected");
1176         }
1177
1178         for (i = 0; i < columns->u.array.n; i++) {
1179             const struct ovsdb_column *column;
1180             const char *s;
1181
1182             if (columns->u.array.elems[i]->type != JSON_STRING) {
1183                 return ovsdb_syntax_error(columns, NULL,
1184                                           "array of column names expected");
1185             }
1186
1187             s = columns->u.array.elems[i]->u.string;
1188             column = shash_find_data(&mt->table->schema->columns, s);
1189             if (!column) {
1190                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1191                                           "column name", s);
1192             }
1193             ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1194                                              allocated_columns);
1195         }
1196     } else {
1197         struct shash_node *node;
1198
1199         SHASH_FOR_EACH (node, &ts->columns) {
1200             const struct ovsdb_column *column = node->data;
1201             if (column->index != OVSDB_COL_UUID) {
1202                 ovsdb_jsonrpc_add_monitor_column(mt, column, select,
1203                                                  allocated_columns);
1204             }
1205         }
1206     }
1207
1208     return NULL;
1209 }
1210
1211 static struct json *
1212 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1213                              struct json *params)
1214 {
1215     struct ovsdb_jsonrpc_monitor *m = NULL;
1216     struct json *monitor_id, *monitor_requests;
1217     struct ovsdb_error *error = NULL;
1218     struct shash_node *node;
1219     struct json *json;
1220
1221     if (json_array(params)->n != 3) {
1222         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1223         goto error;
1224     }
1225     monitor_id = params->u.array.elems[1];
1226     monitor_requests = params->u.array.elems[2];
1227     if (monitor_requests->type != JSON_OBJECT) {
1228         error = ovsdb_syntax_error(monitor_requests, NULL,
1229                                    "monitor-requests must be object");
1230         goto error;
1231     }
1232
1233     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1234         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1235         goto error;
1236     }
1237
1238     m = xzalloc(sizeof *m);
1239     ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
1240     ovsdb_add_replica(db, &m->replica);
1241     m->session = s;
1242     m->db = db;
1243     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1244     m->monitor_id = json_clone(monitor_id);
1245     shash_init(&m->tables);
1246
1247     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1248         const struct ovsdb_table *table;
1249         struct ovsdb_jsonrpc_monitor_table *mt;
1250         size_t allocated_columns;
1251         const struct json *mr_value;
1252         size_t i;
1253
1254         table = ovsdb_get_table(m->db, node->name);
1255         if (!table) {
1256             error = ovsdb_syntax_error(NULL, NULL,
1257                                        "no table named %s", node->name);
1258             goto error;
1259         }
1260
1261         mt = xzalloc(sizeof *mt);
1262         mt->table = table;
1263         shash_add(&m->tables, table->schema->name, mt);
1264
1265         /* Parse columns. */
1266         mr_value = node->data;
1267         allocated_columns = 0;
1268         if (mr_value->type == JSON_ARRAY) {
1269             const struct json_array *array = &mr_value->u.array;
1270
1271             for (i = 0; i < array->n; i++) {
1272                 error = ovsdb_jsonrpc_parse_monitor_request(
1273                     mt, array->elems[i], &allocated_columns);
1274                 if (error) {
1275                     goto error;
1276                 }
1277             }
1278         } else {
1279             error = ovsdb_jsonrpc_parse_monitor_request(
1280                 mt, mr_value, &allocated_columns);
1281             if (error) {
1282                 goto error;
1283             }
1284         }
1285
1286         /* Check for duplicate columns. */
1287         qsort(mt->columns, mt->n_columns, sizeof *mt->columns,
1288               compare_ovsdb_jsonrpc_monitor_column);
1289         for (i = 1; i < mt->n_columns; i++) {
1290             if (mt->columns[i].column == mt->columns[i - 1].column) {
1291                 error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1292                                            "mentioned more than once",
1293                                            mt->columns[i].column->name);
1294                 goto error;
1295             }
1296         }
1297     }
1298
1299     return ovsdb_jsonrpc_monitor_get_initial(m);
1300
1301 error:
1302     if (m) {
1303         ovsdb_remove_replica(m->db, &m->replica);
1304     }
1305
1306     json = ovsdb_error_to_json(error);
1307     ovsdb_error_destroy(error);
1308     return json;
1309 }
1310
1311 static struct jsonrpc_msg *
1312 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1313                              struct json_array *params,
1314                              const struct json *request_id)
1315 {
1316     if (params->n != 1) {
1317         return jsonrpc_create_error(json_string_create("invalid parameters"),
1318                                     request_id);
1319     } else {
1320         struct ovsdb_jsonrpc_monitor *m;
1321
1322         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1323         if (!m) {
1324             return jsonrpc_create_error(json_string_create("unknown monitor"),
1325                                         request_id);
1326         } else {
1327             ovsdb_remove_replica(m->db, &m->replica);
1328             return jsonrpc_create_reply(json_object_create(), request_id);
1329         }
1330     }
1331 }
1332
1333 static void
1334 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1335 {
1336     struct ovsdb_jsonrpc_monitor *m, *next;
1337
1338     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1339         ovsdb_remove_replica(m->db, &m->replica);
1340     }
1341 }
1342
1343 /* Returns an overestimate of the number of bytes of JSON data required to
1344  * report the current contents of the database over all the monitors currently
1345  * configured in 's'.  */
1346 static size_t
1347 ovsdb_jsonrpc_monitor_json_length_all(struct ovsdb_jsonrpc_session *s)
1348 {
1349     struct ovsdb_jsonrpc_monitor *m;
1350     size_t length;
1351
1352     length = 0;
1353     HMAP_FOR_EACH (m, node, &s->monitors) {
1354         length += ovsdb_jsonrpc_monitor_json_length(m);
1355     }
1356     return length;
1357 }
1358
1359 static struct ovsdb_jsonrpc_monitor *
1360 ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
1361 {
1362     ovs_assert(replica->class == &ovsdb_jsonrpc_replica_class);
1363     return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
1364 }
1365
1366 struct ovsdb_jsonrpc_monitor_aux {
1367     bool initial;               /* Sending initial contents of table? */
1368     const struct ovsdb_jsonrpc_monitor *monitor;
1369     struct json *json;          /* JSON for the whole transaction. */
1370
1371     /* Current table.  */
1372     struct ovsdb_jsonrpc_monitor_table *mt;
1373     struct json *table_json;    /* JSON for table's transaction. */
1374 };
1375
1376 static bool
1377 any_reportable_change(const struct ovsdb_jsonrpc_monitor_table *mt,
1378                       const unsigned long int *changed)
1379 {
1380     size_t i;
1381
1382     for (i = 0; i < mt->n_columns; i++) {
1383         const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1384         unsigned int idx = c->column->index;
1385
1386         if (c->select & OJMS_MODIFY && bitmap_is_set(changed, idx)) {
1387             return true;
1388         }
1389     }
1390
1391     return false;
1392 }
1393
1394 static bool
1395 ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
1396                                 const struct ovsdb_row *new,
1397                                 const unsigned long int *changed,
1398                                 void *aux_)
1399 {
1400     struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
1401     const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
1402     struct ovsdb_table *table = new ? new->table : old->table;
1403     enum ovsdb_jsonrpc_monitor_selection type;
1404     struct json *old_json, *new_json;
1405     struct json *row_json;
1406     char uuid[UUID_LEN + 1];
1407     size_t i;
1408
1409     if (!aux->mt || table != aux->mt->table) {
1410         aux->mt = shash_find_data(&m->tables, table->schema->name);
1411         aux->table_json = NULL;
1412         if (!aux->mt) {
1413             /* We don't care about rows in this table at all.  Tell the caller
1414              * to skip it.  */
1415             return false;
1416         }
1417     }
1418
1419     type = (aux->initial ? OJMS_INITIAL
1420             : !old ? OJMS_INSERT
1421             : !new ? OJMS_DELETE
1422             : OJMS_MODIFY);
1423     if (!(aux->mt->select & type)) {
1424         /* We don't care about this type of change (but do want to be called
1425          * back for changes to other rows in the same table). */
1426         return true;
1427     }
1428
1429     if (type == OJMS_MODIFY && !any_reportable_change(aux->mt, changed)) {
1430         /* Nothing of interest changed. */
1431         return true;
1432     }
1433
1434     old_json = new_json = NULL;
1435     if (type & (OJMS_DELETE | OJMS_MODIFY)) {
1436         old_json = json_object_create();
1437     }
1438     if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1439         new_json = json_object_create();
1440     }
1441     for (i = 0; i < aux->mt->n_columns; i++) {
1442         const struct ovsdb_jsonrpc_monitor_column *c = &aux->mt->columns[i];
1443         const struct ovsdb_column *column = c->column;
1444         unsigned int idx = c->column->index;
1445
1446         if (!(type & c->select)) {
1447             /* We don't care about this type of change for this particular
1448              * column (but we will care about it for some other column). */
1449             continue;
1450         }
1451
1452         if ((type == OJMS_MODIFY && bitmap_is_set(changed, idx))
1453             || type == OJMS_DELETE) {
1454             json_object_put(old_json, column->name,
1455                             ovsdb_datum_to_json(&old->fields[idx],
1456                                                 &column->type));
1457         }
1458         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
1459             json_object_put(new_json, column->name,
1460                             ovsdb_datum_to_json(&new->fields[idx],
1461                                                 &column->type));
1462         }
1463     }
1464
1465     /* Create JSON object for transaction overall. */
1466     if (!aux->json) {
1467         aux->json = json_object_create();
1468     }
1469
1470     /* Create JSON object for transaction on this table. */
1471     if (!aux->table_json) {
1472         aux->table_json = json_object_create();
1473         json_object_put(aux->json, aux->mt->table->schema->name,
1474                         aux->table_json);
1475     }
1476
1477     /* Create JSON object for transaction on this row. */
1478     row_json = json_object_create();
1479     if (old_json) {
1480         json_object_put(row_json, "old", old_json);
1481     }
1482     if (new_json) {
1483         json_object_put(row_json, "new", new_json);
1484     }
1485
1486     /* Add JSON row to JSON table. */
1487     snprintf(uuid, sizeof uuid,
1488              UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
1489     json_object_put(aux->table_json, uuid, row_json);
1490
1491     return true;
1492 }
1493
1494 /* Returns an overestimate of the number of bytes of JSON data required to
1495  * report the current contents of the database over monitor 'm'. */
1496 static size_t
1497 ovsdb_jsonrpc_monitor_json_length(const struct ovsdb_jsonrpc_monitor *m)
1498 {
1499     const struct shash_node *node;
1500     size_t length;
1501
1502     /* Top-level overhead of monitor JSON. */
1503     length = 256;
1504
1505     SHASH_FOR_EACH (node, &m->tables) {
1506         const struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1507         const struct ovsdb_table *table = mt->table;
1508         const struct ovsdb_row *row;
1509         size_t i;
1510
1511         /* Per-table JSON overhead: "<table>":{...}. */
1512         length += strlen(table->schema->name) + 32;
1513
1514         /* Per-row JSON overhead: ,"<uuid>":{"old":{...},"new":{...}} */
1515         length += hmap_count(&table->rows) * (UUID_LEN + 32);
1516
1517         /* Per-row, per-column JSON overhead: ,"<column>": */
1518         for (i = 0; i < mt->n_columns; i++) {
1519             const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1520             const struct ovsdb_column *column = c->column;
1521
1522             length += hmap_count(&table->rows) * (8 + strlen(column->name));
1523         }
1524
1525         /* Data. */
1526         HMAP_FOR_EACH (row, hmap_node, &table->rows) {
1527             for (i = 0; i < mt->n_columns; i++) {
1528                 const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i];
1529                 const struct ovsdb_column *column = c->column;
1530
1531                 length += ovsdb_datum_json_length(&row->fields[column->index],
1532                                                   &column->type);
1533             }
1534         }
1535     }
1536
1537     return length;
1538 }
1539
1540 static void
1541 ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
1542                                const struct ovsdb_jsonrpc_monitor *m,
1543                                bool initial)
1544 {
1545     aux->initial = initial;
1546     aux->monitor = m;
1547     aux->json = NULL;
1548     aux->mt = NULL;
1549     aux->table_json = NULL;
1550 }
1551
1552 static struct ovsdb_error *
1553 ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
1554                              const struct ovsdb_txn *txn,
1555                              bool durable OVS_UNUSED)
1556 {
1557     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1558     struct ovsdb_jsonrpc_monitor_aux aux;
1559
1560     ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
1561     ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
1562     if (aux.json) {
1563         struct jsonrpc_msg *msg;
1564         struct json *params;
1565
1566         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
1567                                      aux.json);
1568         msg = jsonrpc_create_notify("update", params);
1569         jsonrpc_session_send(aux.monitor->session->js, msg);
1570     }
1571
1572     return NULL;
1573 }
1574
1575 static struct json *
1576 ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
1577 {
1578     struct ovsdb_jsonrpc_monitor_aux aux;
1579     struct shash_node *node;
1580
1581     ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
1582     SHASH_FOR_EACH (node, &m->tables) {
1583         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1584
1585         if (mt->select & OJMS_INITIAL) {
1586             struct ovsdb_row *row;
1587
1588             HMAP_FOR_EACH (row, hmap_node, &mt->table->rows) {
1589                 ovsdb_jsonrpc_monitor_change_cb(NULL, row, NULL, &aux);
1590             }
1591         }
1592     }
1593     return aux.json ? aux.json : json_object_create();
1594 }
1595
1596 static void
1597 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
1598 {
1599     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
1600     struct shash_node *node;
1601
1602     json_destroy(m->monitor_id);
1603     SHASH_FOR_EACH (node, &m->tables) {
1604         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
1605         free(mt->columns);
1606         free(mt);
1607     }
1608     shash_destroy(&m->tables);
1609     hmap_remove(&m->session->monitors, &m->node);
1610     free(m);
1611 }
1612
1613 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
1614     ovsdb_jsonrpc_monitor_commit,
1615     ovsdb_jsonrpc_monitor_destroy
1616 };