lib/jsonrpc.c

   1 /*
   2  * Copyright (c) 2009 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18
  19 #include "jsonrpc.h"
  20
  21 #include <errno.h>
  22
  23 #include "byteq.h"
  24 #include "json.h"
  25 #include "list.h"
  26 #include "ofpbuf.h"
  27 #include "poll-loop.h"
  28 #include "queue.h"
  29 #include "stream.h"
  30
  31 #define THIS_MODULE VLM_jsonrpc
  32 #include "vlog.h"
  33 \f
  34 struct jsonrpc {
  35     struct stream *stream;
  36     char *name;
  37     int status;
  38
  39     /* Input. */
  40     struct byteq input;
  41     struct json_parser *parser;
  42     struct jsonrpc_msg *received;
  43
  44     /* Output. */
  45     struct ovs_queue output;
  46     size_t backlog;
  47 };
  48
  49 /* Rate limit for error messages. */
  50 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
  51
  52 static void jsonrpc_received(struct jsonrpc *);
  53 static void jsonrpc_cleanup(struct jsonrpc *);
  54
  55 struct jsonrpc *
  56 jsonrpc_open(struct stream *stream)
  57 {
  58     struct jsonrpc *rpc;
  59
  60     assert(stream != NULL);
  61
  62     rpc = xzalloc(sizeof *rpc);
  63     rpc->name = xstrdup(stream_get_name(stream));
  64     rpc->stream = stream;
  65     byteq_init(&rpc->input);
  66     queue_init(&rpc->output);
  67
  68     return rpc;
  69 }
  70
  71 void
  72 jsonrpc_close(struct jsonrpc *rpc)
  73 {
  74     if (rpc) {
  75         jsonrpc_cleanup(rpc);
  76         free(rpc->name);
  77         free(rpc);
  78     }
  79 }
  80
  81 void
  82 jsonrpc_run(struct jsonrpc *rpc)
  83 {
  84     if (rpc->status) {
  85         return;
  86     }
  87
  88     while (!queue_is_empty(&rpc->output)) {
  89         struct ofpbuf *buf = rpc->output.head;
  90         int retval;
  91
  92         retval = stream_send(rpc->stream, buf->data, buf->size);
  93         if (retval >= 0) {
  94             rpc->backlog -= retval;
  95             ofpbuf_pull(buf, retval);
  96             if (!buf->size) {
  97                 ofpbuf_delete(queue_pop_head(&rpc->output));
  98             }
  99         } else {
 100             if (retval != -EAGAIN) {
 101                 VLOG_WARN_RL(&rl, "%s: send error: %s",
 102                              rpc->name, strerror(-retval));
 103                 jsonrpc_error(rpc, -retval);
 104             }
 105             break;
 106         }
 107     }
 108 }
 109
 110 void
 111 jsonrpc_wait(struct jsonrpc *rpc)
 112 {
 113     if (!rpc->status && !queue_is_empty(&rpc->output)) {
 114         stream_send_wait(rpc->stream);
 115     }
 116 }
 117
 118 int
 119 jsonrpc_get_status(const struct jsonrpc *rpc)
 120 {
 121     return rpc->status;
 122 }
 123
 124 size_t
 125 jsonrpc_get_backlog(const struct jsonrpc *rpc)
 126 {
 127     return rpc->status ? 0 : rpc->backlog;
 128 }
 129
 130 const char *
 131 jsonrpc_get_name(const struct jsonrpc *rpc)
 132 {
 133     return rpc->name;
 134 }
 135
 136 int
 137 jsonrpc_send(struct jsonrpc *rpc, struct jsonrpc_msg *msg)
 138 {
 139     struct ofpbuf *buf;
 140     struct json *json;
 141     size_t length;
 142     char *s;
 143
 144     if (rpc->status) {
 145         jsonrpc_msg_destroy(msg);
 146         return rpc->status;
 147     }
 148
 149     json = jsonrpc_msg_to_json(msg);
 150     s = json_to_string(json, 0);
 151     length = strlen(s);
 152     json_destroy(json);
 153
 154     buf = xmalloc(sizeof *buf);
 155     ofpbuf_use(buf, s, length);
 156     buf->size = length;
 157     queue_push_tail(&rpc->output, buf);
 158     rpc->backlog += length;
 159
 160     if (rpc->output.n == 1) {
 161         jsonrpc_run(rpc);
 162     }
 163     return rpc->status;
 164 }
 165
 166 int
 167 jsonrpc_recv(struct jsonrpc *rpc, struct jsonrpc_msg **msgp)
 168 {
 169     *msgp = NULL;
 170     if (rpc->status) {
 171         return rpc->status;
 172     }
 173
 174     while (!rpc->received) {
 175         if (byteq_is_empty(&rpc->input)) {
 176             size_t chunk;
 177             int retval;
 178
 179             chunk = byteq_headroom(&rpc->input);
 180             retval = stream_recv(rpc->stream, byteq_head(&rpc->input), chunk);
 181             if (retval < 0) {
 182                 if (retval == -EAGAIN) {
 183                     return EAGAIN;
 184                 } else {
 185                     VLOG_WARN_RL(&rl, "%s: receive error: %s",
 186                                  rpc->name, strerror(-retval));
 187                     jsonrpc_error(rpc, -retval);
 188                     return rpc->status;
 189                 }
 190             } else if (retval == 0) {
 191                 VLOG_INFO_RL(&rl, "%s: connection closed", rpc->name);
 192                 jsonrpc_error(rpc, EOF);
 193                 return EOF;
 194             }
 195             byteq_advance_head(&rpc->input, retval);
 196         } else {
 197             size_t n, used;
 198
 199             if (!rpc->parser) {
 200                 rpc->parser = json_parser_create(0);
 201             }
 202             n = byteq_tailroom(&rpc->input);
 203             used = json_parser_feed(rpc->parser,
 204                                     (char *) byteq_tail(&rpc->input), n);
 205             byteq_advance_tail(&rpc->input, used);
 206             if (json_parser_is_done(rpc->parser)) {
 207                 jsonrpc_received(rpc);
 208                 if (rpc->status) {
 209                     return rpc->status;
 210                 }
 211             }
 212         }
 213     }
 214
 215     *msgp = rpc->received;
 216     rpc->received = NULL;
 217     return 0;
 218 }
 219
 220 void
 221 jsonrpc_recv_wait(struct jsonrpc *rpc)
 222 {
 223     if (rpc->status || rpc->received || !byteq_is_empty(&rpc->input)) {
 224         poll_immediate_wake();
 225     } else {
 226         stream_recv_wait(rpc->stream);
 227     }
 228 }
 229
 230 int
 231 jsonrpc_send_block(struct jsonrpc *rpc, struct jsonrpc_msg *msg)
 232 {
 233     int error;
 234
 235     error = jsonrpc_send(rpc, msg);
 236     if (error) {
 237         return error;
 238     }
 239
 240     while (!queue_is_empty(&rpc->output) && !rpc->status) {
 241         jsonrpc_run(rpc);
 242         jsonrpc_wait(rpc);
 243         poll_block();
 244     }
 245     return rpc->status;
 246 }
 247
 248 int
 249 jsonrpc_recv_block(struct jsonrpc *rpc, struct jsonrpc_msg **msgp)
 250 {
 251     for (;;) {
 252         int error = jsonrpc_recv(rpc, msgp);
 253         if (error != EAGAIN) {
 254             return error;
 255         }
 256
 257         jsonrpc_run(rpc);
 258         jsonrpc_wait(rpc);
 259         jsonrpc_recv_wait(rpc);
 260         poll_block();
 261     }
 262 }
 263
 264 static void
 265 jsonrpc_received(struct jsonrpc *rpc)
 266 {
 267     struct jsonrpc_msg *msg;
 268     struct json *json;
 269     char *error;
 270
 271     json = json_parser_finish(rpc->parser);
 272     rpc->parser = NULL;
 273     if (json->type == JSON_STRING) {
 274         VLOG_WARN_RL(&rl, "%s: error parsing stream: %s",
 275                      rpc->name, json_string(json));
 276         jsonrpc_error(rpc, EPROTO);
 277         json_destroy(json);
 278         return;
 279     }
 280
 281     error = jsonrpc_msg_from_json(json, &msg);
 282     if (error) {
 283         VLOG_WARN_RL(&rl, "%s: received bad JSON-RPC message: %s",
 284                      rpc->name, error);
 285         free(error);
 286         jsonrpc_error(rpc, EPROTO);
 287         return;
 288     }
 289
 290     rpc->received = msg;
 291 }
 292
 293 void
 294 jsonrpc_error(struct jsonrpc *rpc, int error)
 295 {
 296     assert(error);
 297     if (!rpc->status) {
 298         rpc->status = error;
 299         jsonrpc_cleanup(rpc);
 300     }
 301 }
 302
 303 static void
 304 jsonrpc_cleanup(struct jsonrpc *rpc)
 305 {
 306     stream_close(rpc->stream);
 307     rpc->stream = NULL;
 308
 309     json_parser_abort(rpc->parser);
 310     rpc->parser = NULL;
 311
 312     jsonrpc_msg_destroy(rpc->received);
 313     rpc->received = NULL;
 314
 315     queue_clear(&rpc->output);
 316     rpc->backlog = 0;
 317 }
 318 \f
 319 static struct jsonrpc_msg *
 320 jsonrpc_create(enum jsonrpc_msg_type type, const char *method,
 321                 struct json *params, struct json *result, struct json *error,
 322                 struct json *id)
 323 {
 324     struct jsonrpc_msg *msg = xmalloc(sizeof *msg);
 325     msg->type = type;
 326     msg->method = method ? xstrdup(method) : NULL;
 327     msg->params = params;
 328     msg->result = result;
 329     msg->error = error;
 330     msg->id = id;
 331     return msg;
 332 }
 333
 334 static struct json *
 335 jsonrpc_create_id(void)
 336 {
 337     static unsigned int id;
 338     return json_integer_create(id++);
 339 }
 340
 341 struct jsonrpc_msg *
 342 jsonrpc_create_request(const char *method, struct json *params)
 343 {
 344     return jsonrpc_create(JSONRPC_REQUEST, method, params, NULL, NULL,
 345                            jsonrpc_create_id());
 346 }
 347
 348 struct jsonrpc_msg *
 349 jsonrpc_create_notify(const char *method, struct json *params)
 350 {
 351     return jsonrpc_create(JSONRPC_NOTIFY, method, params, NULL, NULL, NULL);
 352 }
 353
 354 struct jsonrpc_msg *
 355 jsonrpc_create_reply(struct json *result, const struct json *id)
 356 {
 357     return jsonrpc_create(JSONRPC_REPLY, NULL, NULL, result, NULL,
 358                            json_clone(id));
 359 }
 360
 361 struct jsonrpc_msg *
 362 jsonrpc_create_error(struct json *error, const struct json *id)
 363 {
 364     return jsonrpc_create(JSONRPC_REPLY, NULL, NULL, NULL, error,
 365                            json_clone(id));
 366 }
 367
 368 const char *
 369 jsonrpc_msg_type_to_string(enum jsonrpc_msg_type type)
 370 {
 371     switch (type) {
 372     case JSONRPC_REQUEST:
 373         return "request";
 374
 375     case JSONRPC_NOTIFY:
 376         return "notification";
 377
 378     case JSONRPC_REPLY:
 379         return "reply";
 380
 381     case JSONRPC_ERROR:
 382         return "error";
 383     }
 384     return "(null)";
 385 }
 386
 387 char *
 388 jsonrpc_msg_is_valid(const struct jsonrpc_msg *m)
 389 {
 390     const char *type_name;
 391     unsigned int pattern;
 392
 393     if (m->params && m->params->type != JSON_ARRAY) {
 394         return xstrdup("\"params\" must be JSON array");
 395     }
 396
 397     switch (m->type) {
 398     case JSONRPC_REQUEST:
 399         pattern = 0x11001;
 400         break;
 401
 402     case JSONRPC_NOTIFY:
 403         pattern = 0x11000;
 404         break;
 405
 406     case JSONRPC_REPLY:
 407         pattern = 0x00101;
 408         break;
 409
 410     case JSONRPC_ERROR:
 411         pattern = 0x00011;
 412         break;
 413
 414     default:
 415         return xasprintf("invalid JSON-RPC message type %d", m->type);
 416     }
 417
 418     type_name = jsonrpc_msg_type_to_string(m->type);
 419     if ((m->method != NULL) != ((pattern & 0x10000) != 0)) {
 420         return xasprintf("%s must%s have \"method\"",
 421                          type_name, (pattern & 0x10000) ? "" : " not");
 422
 423     }
 424     if ((m->params != NULL) != ((pattern & 0x1000) != 0)) {
 425         return xasprintf("%s must%s have \"params\"",
 426                          type_name, (pattern & 0x1000) ? "" : " not");
 427
 428     }
 429     if ((m->result != NULL) != ((pattern & 0x100) != 0)) {
 430         return xasprintf("%s must%s have \"result\"",
 431                          type_name, (pattern & 0x100) ? "" : " not");
 432
 433     }
 434     if ((m->error != NULL) != ((pattern & 0x10) != 0)) {
 435         return xasprintf("%s must%s have \"error\"",
 436                          type_name, (pattern & 0x10) ? "" : " not");
 437
 438     }
 439     if ((m->id != NULL) != ((pattern & 0x1) != 0)) {
 440         return xasprintf("%s must%s have \"id\"",
 441                          type_name, (pattern & 0x1) ? "" : " not");
 442
 443     }
 444     return NULL;
 445 }
 446
 447 void
 448 jsonrpc_msg_destroy(struct jsonrpc_msg *m)
 449 {
 450     if (m) {
 451         free(m->method);
 452         json_destroy(m->params);
 453         json_destroy(m->result);
 454         json_destroy(m->error);
 455         json_destroy(m->id);
 456         free(m);
 457     }
 458 }
 459
 460 static struct json *
 461 null_from_json_null(struct json *json)
 462 {
 463     if (json && json->type == JSON_NULL) {
 464         json_destroy(json);
 465         return NULL;
 466     }
 467     return json;
 468 }
 469
 470 char *
 471 jsonrpc_msg_from_json(struct json *json, struct jsonrpc_msg **msgp)
 472 {
 473     struct json *method = NULL;
 474     struct jsonrpc_msg *msg = NULL;
 475     struct shash *object;
 476     char *error;
 477
 478     if (json->type != JSON_OBJECT) {
 479         error = xstrdup("message is not a JSON object");
 480         goto exit;
 481     }
 482     object = json_object(json);
 483
 484     method = shash_find_and_delete(object, "method");
 485     if (method && method->type != JSON_STRING) {
 486         error = xstrdup("method is not a JSON string");
 487         goto exit;
 488     }
 489
 490     msg = xzalloc(sizeof *msg);
 491     msg->method = method ? xstrdup(method->u.string) : NULL;
 492     msg->params = null_from_json_null(shash_find_and_delete(object, "params"));
 493     msg->result = null_from_json_null(shash_find_and_delete(object, "result"));
 494     msg->error = null_from_json_null(shash_find_and_delete(object, "error"));
 495     msg->id = null_from_json_null(shash_find_and_delete(object, "id"));
 496     msg->type = (msg->result ? JSONRPC_REPLY
 497                  : msg->error ? JSONRPC_ERROR
 498                  : msg->id ? JSONRPC_REQUEST
 499                  : JSONRPC_NOTIFY);
 500     if (!shash_is_empty(object)) {
 501         error = xasprintf("message has unexpected member \"%s\"",
 502                           shash_first(object)->name);
 503         goto exit;
 504     }
 505     error = jsonrpc_msg_is_valid(msg);
 506     if (error) {
 507         goto exit;
 508     }
 509
 510 exit:
 511     json_destroy(method);
 512     json_destroy(json);
 513     if (error) {
 514         jsonrpc_msg_destroy(msg);
 515         msg = NULL;
 516     }
 517     *msgp = msg;
 518     return error;
 519 }
 520
 521 struct json *
 522 jsonrpc_msg_to_json(struct jsonrpc_msg *m)
 523 {
 524     struct json *json = json_object_create();
 525
 526     if (m->method) {
 527         json_object_put(json, "method", json_string_create_nocopy(m->method));
 528     }
 529
 530     if (m->params) {
 531         json_object_put(json, "params", m->params);
 532     }
 533
 534     if (m->result) {
 535         json_object_put(json, "result", m->result);
 536     } else if (m->type == JSONRPC_ERROR) {
 537         json_object_put(json, "result", json_null_create());
 538     }
 539
 540     if (m->error) {
 541         json_object_put(json, "error", m->error);
 542     } else if (m->type == JSONRPC_REPLY) {
 543         json_object_put(json, "error", json_null_create());
 544     }
 545
 546     if (m->id) {
 547         json_object_put(json, "id", m->id);
 548     } else if (m->type == JSONRPC_NOTIFY) {
 549         json_object_put(json, "id", json_null_create());
 550     }
 551
 552     free(m);
 553
 554     return json;
 555 }