ovsdb/jsonrpc-server.c

   1 /* Copyright (c) 2009, 2010 Nicira Networks
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <config.h>
  17
  18 #include "jsonrpc-server.h"
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22
  23 #include "column.h"
  24 #include "json.h"
  25 #include "jsonrpc.h"
  26 #include "ovsdb-error.h"
  27 #include "ovsdb-parser.h"
  28 #include "ovsdb.h"
  29 #include "reconnect.h"
  30 #include "row.h"
  31 #include "stream.h"
  32 #include "table.h"
  33 #include "timeval.h"
  34 #include "transaction.h"
  35 #include "trigger.h"
  36
  37 #define THIS_MODULE VLM_ovsdb_jsonrpc_server
  38 #include "vlog.h"
  39
  40 struct ovsdb_jsonrpc_remote;
  41 struct ovsdb_jsonrpc_session;
  42
  43 /* Message rate-limiting. */
  44 struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  45
  46 /* Sessions. */
  47 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  48     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  49 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  50 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  51 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  52
  53 /* Triggers. */
  54 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  55                                          struct json *id, struct json *params);
  56 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  57     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  58 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  59 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  60 static void ovsdb_jsonrpc_trigger_complete_done(
  61     struct ovsdb_jsonrpc_session *);
  62
  63 /* Monitors. */
  64 static struct json *ovsdb_jsonrpc_monitor_create(
  65     struct ovsdb_jsonrpc_session *, struct json *params);
  66 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  67     struct ovsdb_jsonrpc_session *,
  68     struct json_array *params,
  69     const struct json *request_id);
  70 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
  71 \f
  72 /* JSON-RPC database server. */
  73
  74 struct ovsdb_jsonrpc_server {
  75     struct ovsdb *db;
  76     unsigned int n_sessions, max_sessions;
  77     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
  78 };
  79
  80 /* A configured remote.  This is either a passive stream listener plus a list
  81  * of the currently connected sessions, or a list of exactly one active
  82  * session. */
  83 struct ovsdb_jsonrpc_remote {
  84     struct ovsdb_jsonrpc_server *server;
  85     struct pstream *listener;   /* Listener, if passive. */
  86     struct list sessions;       /* List of "struct ovsdb_jsonrpc_session"s. */
  87 };
  88
  89 static void ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *,
  90                                             const char *name);
  91 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
  92
  93 struct ovsdb_jsonrpc_server *
  94 ovsdb_jsonrpc_server_create(struct ovsdb *db)
  95 {
  96     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
  97     server->db = db;
  98     server->max_sessions = 64;
  99     shash_init(&server->remotes);
 100     return server;
 101 }
 102
 103 /* Sets 'svr''s current set of remotes to the names in 'new_remotes'.  The data
 104  * values in 'new_remotes' are ignored.
 105  *
 106  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 107  * "tcp:1.2.3.4". */
 108 void
 109 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 110                                  const struct shash *new_remotes)
 111 {
 112     struct shash_node *node, *next;
 113
 114     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 115         if (!shash_find(new_remotes, node->name)) {
 116             ovsdb_jsonrpc_server_del_remote(node);
 117         }
 118     }
 119     SHASH_FOR_EACH (node, new_remotes) {
 120         if (!shash_find(&svr->remotes, node->name)) {
 121             ovsdb_jsonrpc_server_add_remote(svr, node->name);
 122         }
 123     }
 124 }
 125
 126 static void
 127 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 128                                 const char *name)
 129 {
 130     struct ovsdb_jsonrpc_remote *remote;
 131     struct pstream *listener;
 132     int error;
 133
 134     error = pstream_open(name, &listener);
 135     if (error && error != EAFNOSUPPORT) {
 136         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, strerror(error));
 137         return;
 138     }
 139
 140     remote = xmalloc(sizeof *remote);
 141     remote->server = svr;
 142     remote->listener = listener;
 143     list_init(&remote->sessions);
 144     shash_add(&svr->remotes, name, remote);
 145
 146     if (!listener) {
 147         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name));
 148     }
 149 }
 150
 151 static void
 152 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 153 {
 154     struct ovsdb_jsonrpc_remote *remote = node->data;
 155
 156     ovsdb_jsonrpc_session_close_all(remote);
 157     pstream_close(remote->listener);
 158     shash_delete(&remote->server->remotes, node);
 159     free(remote);
 160 }
 161
 162 void
 163 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 164 {
 165     struct shash_node *node;
 166
 167     SHASH_FOR_EACH (node, &svr->remotes) {
 168         struct ovsdb_jsonrpc_remote *remote = node->data;
 169
 170         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 171             struct stream *stream;
 172             int error;
 173
 174             error = pstream_accept(remote->listener, &stream);
 175             if (!error) {
 176                 struct jsonrpc_session *js;
 177                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream));
 178                 ovsdb_jsonrpc_session_create(remote, js);
 179             } else if (error != EAGAIN) {
 180                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 181                              pstream_get_name(remote->listener),
 182                              strerror(error));
 183             }
 184         }
 185
 186         ovsdb_jsonrpc_session_run_all(remote);
 187     }
 188 }
 189
 190 void
 191 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 192 {
 193     struct shash_node *node;
 194
 195     SHASH_FOR_EACH (node, &svr->remotes) {
 196         struct ovsdb_jsonrpc_remote *remote = node->data;
 197
 198         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 199             pstream_wait(remote->listener);
 200         }
 201
 202         ovsdb_jsonrpc_session_wait_all(remote);
 203     }
 204 }
 205 \f
 206 /* JSON-RPC database server session. */
 207
 208 struct ovsdb_jsonrpc_session {
 209     struct ovsdb_jsonrpc_remote *remote;
 210     struct list node;           /* Element in remote's sessions list. */
 211
 212     /* Triggers. */
 213     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 214     struct list completions;    /* Completed triggers. */
 215
 216     /* Monitors. */
 217     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 218
 219     /* Network connectivity. */
 220     struct jsonrpc_session *js;  /* JSON-RPC session. */
 221     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 222 };
 223
 224 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 225 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 226 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 227 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 228                                              struct jsonrpc_msg *);
 229 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 230                                              struct jsonrpc_msg *);
 231
 232 static struct ovsdb_jsonrpc_session *
 233 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 234                              struct jsonrpc_session *js)
 235 {
 236     struct ovsdb_jsonrpc_session *s;
 237
 238     s = xzalloc(sizeof *s);
 239     s->remote = remote;
 240     list_push_back(&remote->sessions, &s->node);
 241     hmap_init(&s->triggers);
 242     hmap_init(&s->monitors);
 243     list_init(&s->completions);
 244     s->js = js;
 245     s->js_seqno = jsonrpc_session_get_seqno(js);
 246
 247     remote->server->n_sessions++;
 248
 249     return s;
 250 }
 251
 252 static void
 253 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 254 {
 255     ovsdb_jsonrpc_monitor_remove_all(s);
 256     jsonrpc_session_close(s->js);
 257     list_remove(&s->node);
 258     s->remote->server->n_sessions--;
 259     free(s);
 260 }
 261
 262 static int
 263 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 264 {
 265     jsonrpc_session_run(s->js);
 266     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 267         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 268         ovsdb_jsonrpc_trigger_complete_all(s);
 269         ovsdb_jsonrpc_monitor_remove_all(s);
 270     }
 271
 272     ovsdb_jsonrpc_trigger_complete_done(s);
 273
 274     if (!jsonrpc_session_get_backlog(s->js)) {
 275         struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
 276         if (msg) {
 277             if (msg->type == JSONRPC_REQUEST) {
 278                 ovsdb_jsonrpc_session_got_request(s, msg);
 279             } else if (msg->type == JSONRPC_NOTIFY) {
 280                 ovsdb_jsonrpc_session_got_notify(s, msg);
 281             } else {
 282                 VLOG_WARN("%s: received unexpected %s message",
 283                           jsonrpc_session_get_name(s->js),
 284                           jsonrpc_msg_type_to_string(msg->type));
 285                 jsonrpc_session_force_reconnect(s->js);
 286                 jsonrpc_msg_destroy(msg);
 287             }
 288         }
 289     }
 290     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 291 }
 292
 293 static void
 294 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 295 {
 296     struct ovsdb_jsonrpc_session *s, *next;
 297
 298     LIST_FOR_EACH_SAFE (s, next, struct ovsdb_jsonrpc_session, node,
 299                         &remote->sessions) {
 300         int error = ovsdb_jsonrpc_session_run(s);
 301         if (error) {
 302             ovsdb_jsonrpc_session_close(s);
 303         }
 304     }
 305 }
 306
 307 static void
 308 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 309 {
 310     jsonrpc_session_wait(s->js);
 311     if (!jsonrpc_session_get_backlog(s->js)) {
 312         jsonrpc_session_recv_wait(s->js);
 313     }
 314 }
 315
 316 static void
 317 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 318 {
 319     struct ovsdb_jsonrpc_session *s;
 320
 321     LIST_FOR_EACH (s, struct ovsdb_jsonrpc_session, node, &remote->sessions) {
 322         ovsdb_jsonrpc_session_wait(s);
 323     }
 324 }
 325
 326 static void
 327 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 328 {
 329     struct ovsdb_jsonrpc_session *s, *next;
 330
 331     LIST_FOR_EACH_SAFE (s, next, struct ovsdb_jsonrpc_session, node,
 332                         &remote->sessions) {
 333         ovsdb_jsonrpc_session_close(s);
 334     }
 335 }
 336
 337 static struct jsonrpc_msg *
 338 execute_transaction(struct ovsdb_jsonrpc_session *s,
 339                     struct jsonrpc_msg *request)
 340 {
 341     ovsdb_jsonrpc_trigger_create(s, request->id, request->params);
 342     request->id = NULL;
 343     request->params = NULL;
 344     jsonrpc_msg_destroy(request);
 345     return NULL;
 346 }
 347
 348 static void
 349 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 350                                   struct jsonrpc_msg *request)
 351 {
 352     struct jsonrpc_msg *reply;
 353
 354     if (!strcmp(request->method, "transact")) {
 355         reply = execute_transaction(s, request);
 356     } else if (!strcmp(request->method, "monitor")) {
 357         reply = jsonrpc_create_reply(
 358             ovsdb_jsonrpc_monitor_create(s, request->params), request->id);
 359     } else if (!strcmp(request->method, "monitor_cancel")) {
 360         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 361                                              request->id);
 362     } else if (!strcmp(request->method, "get_schema")) {
 363         reply = jsonrpc_create_reply(
 364             ovsdb_schema_to_json(s->remote->server->db->schema), request->id);
 365     } else if (!strcmp(request->method, "echo")) {
 366         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 367     } else {
 368         reply = jsonrpc_create_error(json_string_create("unknown method"),
 369                                      request->id);
 370     }
 371
 372     if (reply) {
 373         jsonrpc_msg_destroy(request);
 374         jsonrpc_session_send(s->js, reply);
 375     }
 376 }
 377
 378 static void
 379 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 380 {
 381     if (json_array(request->params)->n == 1) {
 382         struct ovsdb_jsonrpc_trigger *t;
 383         struct json *id;
 384
 385         id = request->params->u.array.elems[0];
 386         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 387         if (t) {
 388             ovsdb_jsonrpc_trigger_complete(t);
 389         }
 390     }
 391 }
 392
 393 static void
 394 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 395                                  struct jsonrpc_msg *request)
 396 {
 397     if (!strcmp(request->method, "cancel")) {
 398         execute_cancel(s, request);
 399     }
 400     jsonrpc_msg_destroy(request);
 401 }
 402 \f
 403 /* JSON-RPC database server triggers.
 404  *
 405  * (Every transaction is treated as a trigger even if it doesn't actually have
 406  * any "wait" operations.) */
 407
 408 struct ovsdb_jsonrpc_trigger {
 409     struct ovsdb_trigger trigger;
 410     struct ovsdb_jsonrpc_session *session;
 411     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 412     struct json *id;
 413 };
 414
 415 static void
 416 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s,
 417                              struct json *id, struct json *params)
 418 {
 419     struct ovsdb_jsonrpc_trigger *t;
 420     size_t hash;
 421
 422     /* Check for duplicate ID. */
 423     hash = json_hash(id, 0);
 424     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 425     if (t) {
 426         struct jsonrpc_msg *msg;
 427
 428         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 429                                    id);
 430         jsonrpc_session_send(s->js, msg);
 431         json_destroy(id);
 432         json_destroy(params);
 433         return;
 434     }
 435
 436     /* Insert into trigger table. */
 437     t = xmalloc(sizeof *t);
 438     ovsdb_trigger_init(s->remote->server->db,
 439                        &t->trigger, params, &s->completions,
 440                        time_msec());
 441     t->session = s;
 442     t->id = id;
 443     hmap_insert(&s->triggers, &t->hmap_node, hash);
 444
 445     /* Complete early if possible. */
 446     if (ovsdb_trigger_is_complete(&t->trigger)) {
 447         ovsdb_jsonrpc_trigger_complete(t);
 448     }
 449 }
 450
 451 static struct ovsdb_jsonrpc_trigger *
 452 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 453                            const struct json *id, size_t hash)
 454 {
 455     struct ovsdb_jsonrpc_trigger *t;
 456
 457     HMAP_FOR_EACH_WITH_HASH (t, struct ovsdb_jsonrpc_trigger, hmap_node, hash,
 458                              &s->triggers) {
 459         if (json_equal(t->id, id)) {
 460             return t;
 461         }
 462     }
 463
 464     return NULL;
 465 }
 466
 467 static void
 468 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 469 {
 470     struct ovsdb_jsonrpc_session *s = t->session;
 471
 472     if (jsonrpc_session_is_connected(s->js)) {
 473         struct jsonrpc_msg *reply;
 474         struct json *result;
 475
 476         result = ovsdb_trigger_steal_result(&t->trigger);
 477         if (result) {
 478             reply = jsonrpc_create_reply(result, t->id);
 479         } else {
 480             reply = jsonrpc_create_error(json_string_create("canceled"),
 481                                          t->id);
 482         }
 483         jsonrpc_session_send(s->js, reply);
 484     }
 485
 486     json_destroy(t->id);
 487     ovsdb_trigger_destroy(&t->trigger);
 488     hmap_remove(&s->triggers, &t->hmap_node);
 489     free(t);
 490 }
 491
 492 static void
 493 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
 494 {
 495     struct ovsdb_jsonrpc_trigger *t, *next;
 496     HMAP_FOR_EACH_SAFE (t, next, struct ovsdb_jsonrpc_trigger, hmap_node,
 497                         &s->triggers) {
 498         ovsdb_jsonrpc_trigger_complete(t);
 499     }
 500 }
 501
 502 static void
 503 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
 504 {
 505     while (!list_is_empty(&s->completions)) {
 506         struct ovsdb_jsonrpc_trigger *t
 507             = CONTAINER_OF(s->completions.next,
 508                            struct ovsdb_jsonrpc_trigger, trigger.node);
 509         ovsdb_jsonrpc_trigger_complete(t);
 510     }
 511 }
 512 \f
 513 /* JSON-RPC database table monitors. */
 514
 515 enum ovsdb_jsonrpc_monitor_selection {
 516     OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
 517     OJMS_INSERT = 1 << 1,       /* New rows. */
 518     OJMS_DELETE = 1 << 2,       /* Deleted rows. */
 519     OJMS_MODIFY = 1 << 3        /* Modified rows. */
 520 };
 521
 522 struct ovsdb_jsonrpc_monitor_table {
 523     const struct ovsdb_table *table;
 524     enum ovsdb_jsonrpc_monitor_selection select;
 525     struct ovsdb_column_set columns;
 526 };
 527
 528 struct ovsdb_jsonrpc_monitor {
 529     struct ovsdb_replica replica;
 530     struct ovsdb_jsonrpc_session *session;
 531     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
 532
 533     struct json *monitor_id;
 534     struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
 535 };
 536
 537 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
 538
 539 struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
 540     struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
 541 static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
 542 static struct json *ovsdb_jsonrpc_monitor_get_initial(
 543     const struct ovsdb_jsonrpc_monitor *);
 544
 545 static bool
 546 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
 547 {
 548     const struct json *json;
 549
 550     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
 551     return json ? json_boolean(json) : default_value;
 552 }
 553
 554 struct ovsdb_jsonrpc_monitor *
 555 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
 556                            const struct json *monitor_id)
 557 {
 558     struct ovsdb_jsonrpc_monitor *m;
 559
 560     HMAP_FOR_EACH_WITH_HASH (m, struct ovsdb_jsonrpc_monitor, node,
 561                              json_hash(monitor_id, 0), &s->monitors) {
 562         if (json_equal(m->monitor_id, monitor_id)) {
 563             return m;
 564         }
 565     }
 566
 567     return NULL;
 568 }
 569
 570 static struct json *
 571 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s,
 572                              struct json *params)
 573 {
 574     struct ovsdb_jsonrpc_monitor *m = NULL;
 575     struct json *monitor_id, *monitor_requests;
 576     struct ovsdb_error *error = NULL;
 577     struct shash_node *node;
 578     struct json *json;
 579
 580     if (json_array(params)->n != 2) {
 581         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
 582         goto error;
 583     }
 584     monitor_id = params->u.array.elems[0];
 585     monitor_requests = params->u.array.elems[1];
 586     if (monitor_requests->type != JSON_OBJECT) {
 587         error = ovsdb_syntax_error(monitor_requests, NULL,
 588                                    "monitor-requests must be object");
 589         goto error;
 590     }
 591
 592     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
 593         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
 594         goto error;
 595     }
 596
 597     m = xzalloc(sizeof *m);
 598     ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
 599     ovsdb_add_replica(s->remote->server->db, &m->replica);
 600     m->session = s;
 601     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
 602     m->monitor_id = json_clone(monitor_id);
 603     shash_init(&m->tables);
 604
 605     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
 606         const struct ovsdb_table *table;
 607         struct ovsdb_jsonrpc_monitor_table *mt;
 608         const struct json *columns_json, *select_json;
 609         struct ovsdb_parser parser;
 610
 611         table = ovsdb_get_table(s->remote->server->db, node->name);
 612         if (!table) {
 613             error = ovsdb_syntax_error(NULL, NULL,
 614                                        "no table named %s", node->name);
 615             goto error;
 616         }
 617
 618         mt = xzalloc(sizeof *mt);
 619         mt->table = table;
 620         mt->select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
 621         ovsdb_column_set_init(&mt->columns);
 622         shash_add(&m->tables, table->schema->name, mt);
 623
 624         ovsdb_parser_init(&parser, node->data, "table %s", node->name);
 625         columns_json = ovsdb_parser_member(&parser, "columns",
 626                                            OP_ARRAY | OP_OPTIONAL);
 627         select_json = ovsdb_parser_member(&parser, "select",
 628                                           OP_OBJECT | OP_OPTIONAL);
 629         error = ovsdb_parser_finish(&parser);
 630         if (error) {
 631             goto error;
 632         }
 633
 634         if (columns_json) {
 635             error = ovsdb_column_set_from_json(columns_json, table,
 636                                                &mt->columns);
 637             if (error) {
 638                 goto error;
 639             }
 640         } else {
 641             struct shash_node *node;
 642
 643             SHASH_FOR_EACH (node, &table->schema->columns) {
 644                 const struct ovsdb_column *column = node->data;
 645                 if (column->index != OVSDB_COL_UUID) {
 646                     ovsdb_column_set_add(&mt->columns, column);
 647                 }
 648             }
 649         }
 650
 651         if (select_json) {
 652             mt->select = 0;
 653             ovsdb_parser_init(&parser, select_json, "table %s select",
 654                               table->schema->name);
 655             if (parse_bool(&parser, "initial", true)) {
 656                 mt->select |= OJMS_INITIAL;
 657             }
 658             if (parse_bool(&parser, "insert", true)) {
 659                 mt->select |= OJMS_INSERT;
 660             }
 661             if (parse_bool(&parser, "delete", true)) {
 662                 mt->select |= OJMS_DELETE;
 663             }
 664             if (parse_bool(&parser, "modify", true)) {
 665                 mt->select |= OJMS_MODIFY;
 666             }
 667             error = ovsdb_parser_finish(&parser);
 668             if (error) {
 669                 goto error;
 670             }
 671         }
 672     }
 673
 674     return ovsdb_jsonrpc_monitor_get_initial(m);
 675
 676 error:
 677     if (m) {
 678         ovsdb_remove_replica(s->remote->server->db, &m->replica);
 679     }
 680
 681     json = ovsdb_error_to_json(error);
 682     ovsdb_error_destroy(error);
 683     return json;
 684 }
 685
 686 static struct jsonrpc_msg *
 687 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
 688                              struct json_array *params,
 689                              const struct json *request_id)
 690 {
 691     if (params->n != 1) {
 692         return jsonrpc_create_error(json_string_create("invalid parameters"),
 693                                     request_id);
 694     } else {
 695         struct ovsdb_jsonrpc_monitor *m;
 696
 697         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
 698         if (!m) {
 699             return jsonrpc_create_error(json_string_create("unknown monitor"),
 700                                         request_id);
 701         } else {
 702             ovsdb_remove_replica(s->remote->server->db, &m->replica);
 703             return jsonrpc_create_reply(json_object_create(), request_id);
 704         }
 705     }
 706 }
 707
 708 static void
 709 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
 710 {
 711     struct ovsdb_jsonrpc_monitor *m, *next;
 712
 713     HMAP_FOR_EACH_SAFE (m, next,
 714                         struct ovsdb_jsonrpc_monitor, node, &s->monitors) {
 715         ovsdb_remove_replica(s->remote->server->db, &m->replica);
 716     }
 717 }
 718
 719 static struct ovsdb_jsonrpc_monitor *
 720 ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
 721 {
 722     assert(replica->class == &ovsdb_jsonrpc_replica_class);
 723     return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
 724 }
 725
 726 struct ovsdb_jsonrpc_monitor_aux {
 727     bool initial;               /* Sending initial contents of table? */
 728     const struct ovsdb_jsonrpc_monitor *monitor;
 729     struct json *json;          /* JSON for the whole transaction. */
 730
 731     /* Current table.  */
 732     struct ovsdb_jsonrpc_monitor_table *mt;
 733     struct json *table_json;    /* JSON for table's transaction. */
 734 };
 735
 736 static bool
 737 ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
 738                                 const struct ovsdb_row *new,
 739                                 void *aux_)
 740 {
 741     struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
 742     const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
 743     struct ovsdb_table *table = new ? new->table : old->table;
 744     enum ovsdb_jsonrpc_monitor_selection type;
 745     struct json *old_json, *new_json;
 746     struct json *row_json;
 747     char uuid[UUID_LEN + 1];
 748     int n_changed;
 749     size_t i;
 750
 751     if (!aux->mt || table != aux->mt->table) {
 752         aux->mt = shash_find_data(&m->tables, table->schema->name);
 753         aux->table_json = NULL;
 754         if (!aux->mt) {
 755             /* We don't care about rows in this table at all.  Tell the caller
 756              * to skip it.  */
 757             return false;
 758         }
 759     }
 760
 761     type = (aux->initial ? OJMS_INITIAL
 762             : !old ? OJMS_INSERT
 763             : !new ? OJMS_DELETE
 764             : OJMS_MODIFY);
 765     if (!(aux->mt->select & type)) {
 766         /* We don't care about this type of change (but do want to be called
 767          * back for changes to other rows in the same table). */
 768         return true;
 769     }
 770
 771     old_json = new_json = NULL;
 772     n_changed = 0;
 773     for (i = 0; i < aux->mt->columns.n_columns; i++) {
 774         const struct ovsdb_column *column = aux->mt->columns.columns[i];
 775         unsigned int idx = column->index;
 776         bool changed = false;
 777
 778         if (type == OJMS_MODIFY) {
 779             changed = !ovsdb_datum_equals(&old->fields[idx],
 780                                           &new->fields[idx], &column->type);
 781             n_changed += changed;
 782         }
 783         if (changed || type == OJMS_DELETE) {
 784             if (!old_json) {
 785                 old_json = json_object_create();
 786             }
 787             json_object_put(old_json, column->name,
 788                             ovsdb_datum_to_json(&old->fields[idx],
 789                                                 &column->type));
 790         }
 791         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
 792             if (!new_json) {
 793                 new_json = json_object_create();
 794             }
 795             json_object_put(new_json, column->name,
 796                             ovsdb_datum_to_json(&new->fields[idx],
 797                                                 &column->type));
 798         }
 799     }
 800     if ((type == OJMS_MODIFY && !n_changed) || (!old_json && !new_json)) {
 801         /* No reportable changes. */
 802         json_destroy(old_json);
 803         json_destroy(new_json);
 804         return true;
 805     }
 806
 807     /* Create JSON object for transaction overall. */
 808     if (!aux->json) {
 809         aux->json = json_object_create();
 810     }
 811
 812     /* Create JSON object for transaction on this table. */
 813     if (!aux->table_json) {
 814         aux->table_json = json_object_create();
 815         json_object_put(aux->json, aux->mt->table->schema->name,
 816                         aux->table_json);
 817     }
 818
 819     /* Create JSON object for transaction on this row. */
 820     row_json = json_object_create();
 821     if (old_json) {
 822         json_object_put(row_json, "old", old_json);
 823     }
 824     if (new_json) {
 825         json_object_put(row_json, "new", new_json);
 826     }
 827
 828     /* Add JSON row to JSON table. */
 829     snprintf(uuid, sizeof uuid,
 830              UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
 831     json_object_put(aux->table_json, uuid, row_json);
 832
 833     return true;
 834 }
 835
 836 static void
 837 ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
 838                                const struct ovsdb_jsonrpc_monitor *m,
 839                                bool initial)
 840 {
 841     aux->initial = initial;
 842     aux->monitor = m;
 843     aux->json = NULL;
 844     aux->mt = NULL;
 845     aux->table_json = NULL;
 846 }
 847
 848 static struct ovsdb_error *
 849 ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
 850                              const struct ovsdb_txn *txn, bool durable UNUSED)
 851 {
 852     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
 853     struct ovsdb_jsonrpc_monitor_aux aux;
 854
 855     ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
 856     ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
 857     if (aux.json) {
 858         struct jsonrpc_msg *msg;
 859         struct json *params;
 860
 861         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
 862                                      aux.json);
 863         msg = jsonrpc_create_notify("update", params);
 864         jsonrpc_session_send(aux.monitor->session->js, msg);
 865     }
 866
 867     return NULL;
 868 }
 869
 870 static struct json *
 871 ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
 872 {
 873     struct ovsdb_jsonrpc_monitor_aux aux;
 874     struct shash_node *node;
 875
 876     ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
 877     SHASH_FOR_EACH (node, &m->tables) {
 878         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
 879
 880         if (mt->select & OJMS_INITIAL) {
 881             struct ovsdb_row *row;
 882
 883             HMAP_FOR_EACH (row, struct ovsdb_row, hmap_node,
 884                            &mt->table->rows) {
 885                 ovsdb_jsonrpc_monitor_change_cb(NULL, row, &aux);
 886             }
 887         }
 888     }
 889     return aux.json ? aux.json : json_object_create();
 890 }
 891
 892 static void
 893 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
 894 {
 895     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
 896     struct shash_node *node;
 897
 898     json_destroy(m->monitor_id);
 899     SHASH_FOR_EACH (node, &m->tables) {
 900         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
 901         ovsdb_column_set_destroy(&mt->columns);
 902         free(mt);
 903     }
 904     shash_destroy(&m->tables);
 905     hmap_remove(&m->session->monitors, &m->node);
 906     free(m);
 907 }
 908
 909 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
 910     ovsdb_jsonrpc_monitor_commit,
 911     ovsdb_jsonrpc_monitor_destroy
 912 };