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 void
 104 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 105 {
 106     struct shash_node *node, *next;
 107
 108     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 109         ovsdb_jsonrpc_server_del_remote(node);
 110     }
 111     shash_destroy(&svr->remotes);
 112     free(svr);
 113 }
 114
 115 /* Sets 'svr''s current set of remotes to the names in 'new_remotes'.  The data
 116  * values in 'new_remotes' are ignored.
 117  *
 118  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 119  * "tcp:1.2.3.4". */
 120 void
 121 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 122                                  const struct shash *new_remotes)
 123 {
 124     struct shash_node *node, *next;
 125
 126     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 127         if (!shash_find(new_remotes, node->name)) {
 128             ovsdb_jsonrpc_server_del_remote(node);
 129         }
 130     }
 131     SHASH_FOR_EACH (node, new_remotes) {
 132         if (!shash_find(&svr->remotes, node->name)) {
 133             ovsdb_jsonrpc_server_add_remote(svr, node->name);
 134         }
 135     }
 136 }
 137
 138 static void
 139 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 140                                 const char *name)
 141 {
 142     struct ovsdb_jsonrpc_remote *remote;
 143     struct pstream *listener;
 144     int error;
 145
 146     error = pstream_open(name, &listener);
 147     if (error && error != EAFNOSUPPORT) {
 148         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, strerror(error));
 149         return;
 150     }
 151
 152     remote = xmalloc(sizeof *remote);
 153     remote->server = svr;
 154     remote->listener = listener;
 155     list_init(&remote->sessions);
 156     shash_add(&svr->remotes, name, remote);
 157
 158     if (!listener) {
 159         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name));
 160     }
 161 }
 162
 163 static void
 164 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 165 {
 166     struct ovsdb_jsonrpc_remote *remote = node->data;
 167
 168     ovsdb_jsonrpc_session_close_all(remote);
 169     pstream_close(remote->listener);
 170     shash_delete(&remote->server->remotes, node);
 171     free(remote);
 172 }
 173
 174 void
 175 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 176 {
 177     struct shash_node *node;
 178
 179     SHASH_FOR_EACH (node, &svr->remotes) {
 180         struct ovsdb_jsonrpc_remote *remote = node->data;
 181
 182         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 183             struct stream *stream;
 184             int error;
 185
 186             error = pstream_accept(remote->listener, &stream);
 187             if (!error) {
 188                 struct jsonrpc_session *js;
 189                 js = jsonrpc_session_open_unreliably(jsonrpc_open(stream));
 190                 ovsdb_jsonrpc_session_create(remote, js);
 191             } else if (error != EAGAIN) {
 192                 VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 193                              pstream_get_name(remote->listener),
 194                              strerror(error));
 195             }
 196         }
 197
 198         ovsdb_jsonrpc_session_run_all(remote);
 199     }
 200 }
 201
 202 void
 203 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 204 {
 205     struct shash_node *node;
 206
 207     SHASH_FOR_EACH (node, &svr->remotes) {
 208         struct ovsdb_jsonrpc_remote *remote = node->data;
 209
 210         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 211             pstream_wait(remote->listener);
 212         }
 213
 214         ovsdb_jsonrpc_session_wait_all(remote);
 215     }
 216 }
 217 \f
 218 /* JSON-RPC database server session. */
 219
 220 struct ovsdb_jsonrpc_session {
 221     struct ovsdb_jsonrpc_remote *remote;
 222     struct list node;           /* Element in remote's sessions list. */
 223
 224     /* Triggers. */
 225     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 226     struct list completions;    /* Completed triggers. */
 227
 228     /* Monitors. */
 229     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 230
 231     /* Network connectivity. */
 232     struct jsonrpc_session *js;  /* JSON-RPC session. */
 233     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 234 };
 235
 236 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 237 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 238 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 239 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 240                                              struct jsonrpc_msg *);
 241 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 242                                              struct jsonrpc_msg *);
 243
 244 static struct ovsdb_jsonrpc_session *
 245 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 246                              struct jsonrpc_session *js)
 247 {
 248     struct ovsdb_jsonrpc_session *s;
 249
 250     s = xzalloc(sizeof *s);
 251     s->remote = remote;
 252     list_push_back(&remote->sessions, &s->node);
 253     hmap_init(&s->triggers);
 254     hmap_init(&s->monitors);
 255     list_init(&s->completions);
 256     s->js = js;
 257     s->js_seqno = jsonrpc_session_get_seqno(js);
 258
 259     remote->server->n_sessions++;
 260
 261     return s;
 262 }
 263
 264 static void
 265 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 266 {
 267     ovsdb_jsonrpc_monitor_remove_all(s);
 268     jsonrpc_session_close(s->js);
 269     list_remove(&s->node);
 270     s->remote->server->n_sessions--;
 271     free(s);
 272 }
 273
 274 static int
 275 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 276 {
 277     jsonrpc_session_run(s->js);
 278     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 279         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 280         ovsdb_jsonrpc_trigger_complete_all(s);
 281         ovsdb_jsonrpc_monitor_remove_all(s);
 282     }
 283
 284     ovsdb_jsonrpc_trigger_complete_done(s);
 285
 286     if (!jsonrpc_session_get_backlog(s->js)) {
 287         struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
 288         if (msg) {
 289             if (msg->type == JSONRPC_REQUEST) {
 290                 ovsdb_jsonrpc_session_got_request(s, msg);
 291             } else if (msg->type == JSONRPC_NOTIFY) {
 292                 ovsdb_jsonrpc_session_got_notify(s, msg);
 293             } else {
 294                 VLOG_WARN("%s: received unexpected %s message",
 295                           jsonrpc_session_get_name(s->js),
 296                           jsonrpc_msg_type_to_string(msg->type));
 297                 jsonrpc_session_force_reconnect(s->js);
 298                 jsonrpc_msg_destroy(msg);
 299             }
 300         }
 301     }
 302     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 303 }
 304
 305 static void
 306 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 307 {
 308     struct ovsdb_jsonrpc_session *s, *next;
 309
 310     LIST_FOR_EACH_SAFE (s, next, struct ovsdb_jsonrpc_session, node,
 311                         &remote->sessions) {
 312         int error = ovsdb_jsonrpc_session_run(s);
 313         if (error) {
 314             ovsdb_jsonrpc_session_close(s);
 315         }
 316     }
 317 }
 318
 319 static void
 320 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 321 {
 322     jsonrpc_session_wait(s->js);
 323     if (!jsonrpc_session_get_backlog(s->js)) {
 324         jsonrpc_session_recv_wait(s->js);
 325     }
 326 }
 327
 328 static void
 329 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 330 {
 331     struct ovsdb_jsonrpc_session *s;
 332
 333     LIST_FOR_EACH (s, struct ovsdb_jsonrpc_session, node, &remote->sessions) {
 334         ovsdb_jsonrpc_session_wait(s);
 335     }
 336 }
 337
 338 static void
 339 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 340 {
 341     struct ovsdb_jsonrpc_session *s, *next;
 342
 343     LIST_FOR_EACH_SAFE (s, next, struct ovsdb_jsonrpc_session, node,
 344                         &remote->sessions) {
 345         ovsdb_jsonrpc_session_close(s);
 346     }
 347 }
 348
 349 static struct jsonrpc_msg *
 350 execute_transaction(struct ovsdb_jsonrpc_session *s,
 351                     struct jsonrpc_msg *request)
 352 {
 353     ovsdb_jsonrpc_trigger_create(s, request->id, request->params);
 354     request->id = NULL;
 355     request->params = NULL;
 356     jsonrpc_msg_destroy(request);
 357     return NULL;
 358 }
 359
 360 static void
 361 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 362                                   struct jsonrpc_msg *request)
 363 {
 364     struct jsonrpc_msg *reply;
 365
 366     if (!strcmp(request->method, "transact")) {
 367         reply = execute_transaction(s, request);
 368     } else if (!strcmp(request->method, "monitor")) {
 369         reply = jsonrpc_create_reply(
 370             ovsdb_jsonrpc_monitor_create(s, request->params), request->id);
 371     } else if (!strcmp(request->method, "monitor_cancel")) {
 372         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 373                                              request->id);
 374     } else if (!strcmp(request->method, "get_schema")) {
 375         reply = jsonrpc_create_reply(
 376             ovsdb_schema_to_json(s->remote->server->db->schema), request->id);
 377     } else if (!strcmp(request->method, "echo")) {
 378         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 379     } else {
 380         reply = jsonrpc_create_error(json_string_create("unknown method"),
 381                                      request->id);
 382     }
 383
 384     if (reply) {
 385         jsonrpc_msg_destroy(request);
 386         jsonrpc_session_send(s->js, reply);
 387     }
 388 }
 389
 390 static void
 391 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 392 {
 393     if (json_array(request->params)->n == 1) {
 394         struct ovsdb_jsonrpc_trigger *t;
 395         struct json *id;
 396
 397         id = request->params->u.array.elems[0];
 398         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 399         if (t) {
 400             ovsdb_jsonrpc_trigger_complete(t);
 401         }
 402     }
 403 }
 404
 405 static void
 406 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 407                                  struct jsonrpc_msg *request)
 408 {
 409     if (!strcmp(request->method, "cancel")) {
 410         execute_cancel(s, request);
 411     }
 412     jsonrpc_msg_destroy(request);
 413 }
 414 \f
 415 /* JSON-RPC database server triggers.
 416  *
 417  * (Every transaction is treated as a trigger even if it doesn't actually have
 418  * any "wait" operations.) */
 419
 420 struct ovsdb_jsonrpc_trigger {
 421     struct ovsdb_trigger trigger;
 422     struct ovsdb_jsonrpc_session *session;
 423     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 424     struct json *id;
 425 };
 426
 427 static void
 428 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s,
 429                              struct json *id, struct json *params)
 430 {
 431     struct ovsdb_jsonrpc_trigger *t;
 432     size_t hash;
 433
 434     /* Check for duplicate ID. */
 435     hash = json_hash(id, 0);
 436     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 437     if (t) {
 438         struct jsonrpc_msg *msg;
 439
 440         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 441                                    id);
 442         jsonrpc_session_send(s->js, msg);
 443         json_destroy(id);
 444         json_destroy(params);
 445         return;
 446     }
 447
 448     /* Insert into trigger table. */
 449     t = xmalloc(sizeof *t);
 450     ovsdb_trigger_init(s->remote->server->db,
 451                        &t->trigger, params, &s->completions,
 452                        time_msec());
 453     t->session = s;
 454     t->id = id;
 455     hmap_insert(&s->triggers, &t->hmap_node, hash);
 456
 457     /* Complete early if possible. */
 458     if (ovsdb_trigger_is_complete(&t->trigger)) {
 459         ovsdb_jsonrpc_trigger_complete(t);
 460     }
 461 }
 462
 463 static struct ovsdb_jsonrpc_trigger *
 464 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 465                            const struct json *id, size_t hash)
 466 {
 467     struct ovsdb_jsonrpc_trigger *t;
 468
 469     HMAP_FOR_EACH_WITH_HASH (t, struct ovsdb_jsonrpc_trigger, hmap_node, hash,
 470                              &s->triggers) {
 471         if (json_equal(t->id, id)) {
 472             return t;
 473         }
 474     }
 475
 476     return NULL;
 477 }
 478
 479 static void
 480 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 481 {
 482     struct ovsdb_jsonrpc_session *s = t->session;
 483
 484     if (jsonrpc_session_is_connected(s->js)) {
 485         struct jsonrpc_msg *reply;
 486         struct json *result;
 487
 488         result = ovsdb_trigger_steal_result(&t->trigger);
 489         if (result) {
 490             reply = jsonrpc_create_reply(result, t->id);
 491         } else {
 492             reply = jsonrpc_create_error(json_string_create("canceled"),
 493                                          t->id);
 494         }
 495         jsonrpc_session_send(s->js, reply);
 496     }
 497
 498     json_destroy(t->id);
 499     ovsdb_trigger_destroy(&t->trigger);
 500     hmap_remove(&s->triggers, &t->hmap_node);
 501     free(t);
 502 }
 503
 504 static void
 505 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
 506 {
 507     struct ovsdb_jsonrpc_trigger *t, *next;
 508     HMAP_FOR_EACH_SAFE (t, next, struct ovsdb_jsonrpc_trigger, hmap_node,
 509                         &s->triggers) {
 510         ovsdb_jsonrpc_trigger_complete(t);
 511     }
 512 }
 513
 514 static void
 515 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
 516 {
 517     while (!list_is_empty(&s->completions)) {
 518         struct ovsdb_jsonrpc_trigger *t
 519             = CONTAINER_OF(s->completions.next,
 520                            struct ovsdb_jsonrpc_trigger, trigger.node);
 521         ovsdb_jsonrpc_trigger_complete(t);
 522     }
 523 }
 524 \f
 525 /* JSON-RPC database table monitors. */
 526
 527 enum ovsdb_jsonrpc_monitor_selection {
 528     OJMS_INITIAL = 1 << 0,      /* All rows when monitor is created. */
 529     OJMS_INSERT = 1 << 1,       /* New rows. */
 530     OJMS_DELETE = 1 << 2,       /* Deleted rows. */
 531     OJMS_MODIFY = 1 << 3        /* Modified rows. */
 532 };
 533
 534 struct ovsdb_jsonrpc_monitor_table {
 535     const struct ovsdb_table *table;
 536     enum ovsdb_jsonrpc_monitor_selection select;
 537     struct ovsdb_column_set columns;
 538 };
 539
 540 struct ovsdb_jsonrpc_monitor {
 541     struct ovsdb_replica replica;
 542     struct ovsdb_jsonrpc_session *session;
 543     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
 544
 545     struct json *monitor_id;
 546     struct shash tables;     /* Holds "struct ovsdb_jsonrpc_monitor_table"s. */
 547 };
 548
 549 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class;
 550
 551 struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find(
 552     struct ovsdb_jsonrpc_session *, const struct json *monitor_id);
 553 static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *);
 554 static struct json *ovsdb_jsonrpc_monitor_get_initial(
 555     const struct ovsdb_jsonrpc_monitor *);
 556
 557 static bool
 558 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
 559 {
 560     const struct json *json;
 561
 562     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
 563     return json ? json_boolean(json) : default_value;
 564 }
 565
 566 struct ovsdb_jsonrpc_monitor *
 567 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
 568                            const struct json *monitor_id)
 569 {
 570     struct ovsdb_jsonrpc_monitor *m;
 571
 572     HMAP_FOR_EACH_WITH_HASH (m, struct ovsdb_jsonrpc_monitor, node,
 573                              json_hash(monitor_id, 0), &s->monitors) {
 574         if (json_equal(m->monitor_id, monitor_id)) {
 575             return m;
 576         }
 577     }
 578
 579     return NULL;
 580 }
 581
 582 static struct json *
 583 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s,
 584                              struct json *params)
 585 {
 586     struct ovsdb_jsonrpc_monitor *m = NULL;
 587     struct json *monitor_id, *monitor_requests;
 588     struct ovsdb_error *error = NULL;
 589     struct shash_node *node;
 590     struct json *json;
 591
 592     if (json_array(params)->n != 2) {
 593         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
 594         goto error;
 595     }
 596     monitor_id = params->u.array.elems[0];
 597     monitor_requests = params->u.array.elems[1];
 598     if (monitor_requests->type != JSON_OBJECT) {
 599         error = ovsdb_syntax_error(monitor_requests, NULL,
 600                                    "monitor-requests must be object");
 601         goto error;
 602     }
 603
 604     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
 605         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
 606         goto error;
 607     }
 608
 609     m = xzalloc(sizeof *m);
 610     ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class);
 611     ovsdb_add_replica(s->remote->server->db, &m->replica);
 612     m->session = s;
 613     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
 614     m->monitor_id = json_clone(monitor_id);
 615     shash_init(&m->tables);
 616
 617     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
 618         const struct ovsdb_table *table;
 619         struct ovsdb_jsonrpc_monitor_table *mt;
 620         const struct json *columns_json, *select_json;
 621         struct ovsdb_parser parser;
 622
 623         table = ovsdb_get_table(s->remote->server->db, node->name);
 624         if (!table) {
 625             error = ovsdb_syntax_error(NULL, NULL,
 626                                        "no table named %s", node->name);
 627             goto error;
 628         }
 629
 630         mt = xzalloc(sizeof *mt);
 631         mt->table = table;
 632         mt->select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
 633         ovsdb_column_set_init(&mt->columns);
 634         shash_add(&m->tables, table->schema->name, mt);
 635
 636         ovsdb_parser_init(&parser, node->data, "table %s", node->name);
 637         columns_json = ovsdb_parser_member(&parser, "columns",
 638                                            OP_ARRAY | OP_OPTIONAL);
 639         select_json = ovsdb_parser_member(&parser, "select",
 640                                           OP_OBJECT | OP_OPTIONAL);
 641         error = ovsdb_parser_finish(&parser);
 642         if (error) {
 643             goto error;
 644         }
 645
 646         if (columns_json) {
 647             error = ovsdb_column_set_from_json(columns_json, table,
 648                                                &mt->columns);
 649             if (error) {
 650                 goto error;
 651             }
 652         } else {
 653             struct shash_node *node;
 654
 655             SHASH_FOR_EACH (node, &table->schema->columns) {
 656                 const struct ovsdb_column *column = node->data;
 657                 if (column->index != OVSDB_COL_UUID) {
 658                     ovsdb_column_set_add(&mt->columns, column);
 659                 }
 660             }
 661         }
 662
 663         if (select_json) {
 664             mt->select = 0;
 665             ovsdb_parser_init(&parser, select_json, "table %s select",
 666                               table->schema->name);
 667             if (parse_bool(&parser, "initial", true)) {
 668                 mt->select |= OJMS_INITIAL;
 669             }
 670             if (parse_bool(&parser, "insert", true)) {
 671                 mt->select |= OJMS_INSERT;
 672             }
 673             if (parse_bool(&parser, "delete", true)) {
 674                 mt->select |= OJMS_DELETE;
 675             }
 676             if (parse_bool(&parser, "modify", true)) {
 677                 mt->select |= OJMS_MODIFY;
 678             }
 679             error = ovsdb_parser_finish(&parser);
 680             if (error) {
 681                 goto error;
 682             }
 683         }
 684     }
 685
 686     return ovsdb_jsonrpc_monitor_get_initial(m);
 687
 688 error:
 689     if (m) {
 690         ovsdb_remove_replica(s->remote->server->db, &m->replica);
 691     }
 692
 693     json = ovsdb_error_to_json(error);
 694     ovsdb_error_destroy(error);
 695     return json;
 696 }
 697
 698 static struct jsonrpc_msg *
 699 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
 700                              struct json_array *params,
 701                              const struct json *request_id)
 702 {
 703     if (params->n != 1) {
 704         return jsonrpc_create_error(json_string_create("invalid parameters"),
 705                                     request_id);
 706     } else {
 707         struct ovsdb_jsonrpc_monitor *m;
 708
 709         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
 710         if (!m) {
 711             return jsonrpc_create_error(json_string_create("unknown monitor"),
 712                                         request_id);
 713         } else {
 714             ovsdb_remove_replica(s->remote->server->db, &m->replica);
 715             return jsonrpc_create_reply(json_object_create(), request_id);
 716         }
 717     }
 718 }
 719
 720 static void
 721 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
 722 {
 723     struct ovsdb_jsonrpc_monitor *m, *next;
 724
 725     HMAP_FOR_EACH_SAFE (m, next,
 726                         struct ovsdb_jsonrpc_monitor, node, &s->monitors) {
 727         ovsdb_remove_replica(s->remote->server->db, &m->replica);
 728     }
 729 }
 730
 731 static struct ovsdb_jsonrpc_monitor *
 732 ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica)
 733 {
 734     assert(replica->class == &ovsdb_jsonrpc_replica_class);
 735     return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica);
 736 }
 737
 738 struct ovsdb_jsonrpc_monitor_aux {
 739     bool initial;               /* Sending initial contents of table? */
 740     const struct ovsdb_jsonrpc_monitor *monitor;
 741     struct json *json;          /* JSON for the whole transaction. */
 742
 743     /* Current table.  */
 744     struct ovsdb_jsonrpc_monitor_table *mt;
 745     struct json *table_json;    /* JSON for table's transaction. */
 746 };
 747
 748 static bool
 749 ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old,
 750                                 const struct ovsdb_row *new,
 751                                 void *aux_)
 752 {
 753     struct ovsdb_jsonrpc_monitor_aux *aux = aux_;
 754     const struct ovsdb_jsonrpc_monitor *m = aux->monitor;
 755     struct ovsdb_table *table = new ? new->table : old->table;
 756     enum ovsdb_jsonrpc_monitor_selection type;
 757     struct json *old_json, *new_json;
 758     struct json *row_json;
 759     char uuid[UUID_LEN + 1];
 760     int n_changed;
 761     size_t i;
 762
 763     if (!aux->mt || table != aux->mt->table) {
 764         aux->mt = shash_find_data(&m->tables, table->schema->name);
 765         aux->table_json = NULL;
 766         if (!aux->mt) {
 767             /* We don't care about rows in this table at all.  Tell the caller
 768              * to skip it.  */
 769             return false;
 770         }
 771     }
 772
 773     type = (aux->initial ? OJMS_INITIAL
 774             : !old ? OJMS_INSERT
 775             : !new ? OJMS_DELETE
 776             : OJMS_MODIFY);
 777     if (!(aux->mt->select & type)) {
 778         /* We don't care about this type of change (but do want to be called
 779          * back for changes to other rows in the same table). */
 780         return true;
 781     }
 782
 783     old_json = new_json = NULL;
 784     n_changed = 0;
 785     for (i = 0; i < aux->mt->columns.n_columns; i++) {
 786         const struct ovsdb_column *column = aux->mt->columns.columns[i];
 787         unsigned int idx = column->index;
 788         bool changed = false;
 789
 790         if (type == OJMS_MODIFY) {
 791             changed = !ovsdb_datum_equals(&old->fields[idx],
 792                                           &new->fields[idx], &column->type);
 793             n_changed += changed;
 794         }
 795         if (changed || type == OJMS_DELETE) {
 796             if (!old_json) {
 797                 old_json = json_object_create();
 798             }
 799             json_object_put(old_json, column->name,
 800                             ovsdb_datum_to_json(&old->fields[idx],
 801                                                 &column->type));
 802         }
 803         if (type & (OJMS_INITIAL | OJMS_INSERT | OJMS_MODIFY)) {
 804             if (!new_json) {
 805                 new_json = json_object_create();
 806             }
 807             json_object_put(new_json, column->name,
 808                             ovsdb_datum_to_json(&new->fields[idx],
 809                                                 &column->type));
 810         }
 811     }
 812     if ((type == OJMS_MODIFY && !n_changed) || (!old_json && !new_json)) {
 813         /* No reportable changes. */
 814         json_destroy(old_json);
 815         json_destroy(new_json);
 816         return true;
 817     }
 818
 819     /* Create JSON object for transaction overall. */
 820     if (!aux->json) {
 821         aux->json = json_object_create();
 822     }
 823
 824     /* Create JSON object for transaction on this table. */
 825     if (!aux->table_json) {
 826         aux->table_json = json_object_create();
 827         json_object_put(aux->json, aux->mt->table->schema->name,
 828                         aux->table_json);
 829     }
 830
 831     /* Create JSON object for transaction on this row. */
 832     row_json = json_object_create();
 833     if (old_json) {
 834         json_object_put(row_json, "old", old_json);
 835     }
 836     if (new_json) {
 837         json_object_put(row_json, "new", new_json);
 838     }
 839
 840     /* Add JSON row to JSON table. */
 841     snprintf(uuid, sizeof uuid,
 842              UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
 843     json_object_put(aux->table_json, uuid, row_json);
 844
 845     return true;
 846 }
 847
 848 static void
 849 ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux,
 850                                const struct ovsdb_jsonrpc_monitor *m,
 851                                bool initial)
 852 {
 853     aux->initial = initial;
 854     aux->monitor = m;
 855     aux->json = NULL;
 856     aux->mt = NULL;
 857     aux->table_json = NULL;
 858 }
 859
 860 static struct ovsdb_error *
 861 ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
 862                              const struct ovsdb_txn *txn, bool durable UNUSED)
 863 {
 864     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
 865     struct ovsdb_jsonrpc_monitor_aux aux;
 866
 867     ovsdb_jsonrpc_monitor_init_aux(&aux, m, false);
 868     ovsdb_txn_for_each_change(txn, ovsdb_jsonrpc_monitor_change_cb, &aux);
 869     if (aux.json) {
 870         struct jsonrpc_msg *msg;
 871         struct json *params;
 872
 873         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
 874                                      aux.json);
 875         msg = jsonrpc_create_notify("update", params);
 876         jsonrpc_session_send(aux.monitor->session->js, msg);
 877     }
 878
 879     return NULL;
 880 }
 881
 882 static struct json *
 883 ovsdb_jsonrpc_monitor_get_initial(const struct ovsdb_jsonrpc_monitor *m)
 884 {
 885     struct ovsdb_jsonrpc_monitor_aux aux;
 886     struct shash_node *node;
 887
 888     ovsdb_jsonrpc_monitor_init_aux(&aux, m, true);
 889     SHASH_FOR_EACH (node, &m->tables) {
 890         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
 891
 892         if (mt->select & OJMS_INITIAL) {
 893             struct ovsdb_row *row;
 894
 895             HMAP_FOR_EACH (row, struct ovsdb_row, hmap_node,
 896                            &mt->table->rows) {
 897                 ovsdb_jsonrpc_monitor_change_cb(NULL, row, &aux);
 898             }
 899         }
 900     }
 901     return aux.json ? aux.json : json_object_create();
 902 }
 903
 904 static void
 905 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *replica)
 906 {
 907     struct ovsdb_jsonrpc_monitor *m = ovsdb_jsonrpc_monitor_cast(replica);
 908     struct shash_node *node;
 909
 910     json_destroy(m->monitor_id);
 911     SHASH_FOR_EACH (node, &m->tables) {
 912         struct ovsdb_jsonrpc_monitor_table *mt = node->data;
 913         ovsdb_column_set_destroy(&mt->columns);
 914         free(mt);
 915     }
 916     shash_destroy(&m->tables);
 917     hmap_remove(&m->session->monitors, &m->node);
 918     free(m);
 919 }
 920
 921 static const struct ovsdb_replica_class ovsdb_jsonrpc_replica_class = {
 922     ovsdb_jsonrpc_monitor_commit,
 923     ovsdb_jsonrpc_monitor_destroy
 924 };