2 * Copyright (c) 2009, 2010, 2011, 2012 Nicira Networks.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
25 #include "dynamic-string.h"
26 #include "fatal-signal.h"
30 #include "poll-loop.h"
31 #include "reconnect.h"
36 VLOG_DEFINE_THIS_MODULE(jsonrpc);
39 struct stream *stream;
45 struct json_parser *parser;
46 struct jsonrpc_msg *received;
49 struct list output; /* Contains "struct ofpbuf"s. */
53 /* Rate limit for error messages. */
54 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
56 static void jsonrpc_received(struct jsonrpc *);
57 static void jsonrpc_cleanup(struct jsonrpc *);
58 static void jsonrpc_error(struct jsonrpc *, int error);
60 /* This is just the same as stream_open() except that it uses the default
61 * JSONRPC ports if none is specified. */
63 jsonrpc_stream_open(const char *name, struct stream **streamp)
65 return stream_open_with_default_ports(name, JSONRPC_TCP_PORT,
66 JSONRPC_SSL_PORT, streamp);
69 /* This is just the same as pstream_open() except that it uses the default
70 * JSONRPC ports if none is specified. */
72 jsonrpc_pstream_open(const char *name, struct pstream **pstreamp)
74 return pstream_open_with_default_ports(name, JSONRPC_TCP_PORT,
75 JSONRPC_SSL_PORT, pstreamp);
78 /* Returns a new JSON-RPC stream that uses 'stream' for input and output. The
79 * new jsonrpc object takes ownership of 'stream'. */
81 jsonrpc_open(struct stream *stream)
85 assert(stream != NULL);
87 rpc = xzalloc(sizeof *rpc);
88 rpc->name = xstrdup(stream_get_name(stream));
90 byteq_init(&rpc->input);
91 list_init(&rpc->output);
96 /* Destroys 'rpc', closing the stream on which it is based, and frees its
99 jsonrpc_close(struct jsonrpc *rpc)
102 jsonrpc_cleanup(rpc);
108 /* Performs periodic maintenance on 'rpc', such as flushing output buffers. */
110 jsonrpc_run(struct jsonrpc *rpc)
116 stream_run(rpc->stream);
117 while (!list_is_empty(&rpc->output)) {
118 struct ofpbuf *buf = ofpbuf_from_list(rpc->output.next);
121 retval = stream_send(rpc->stream, buf->data, buf->size);
123 rpc->backlog -= retval;
124 ofpbuf_pull(buf, retval);
126 list_remove(&buf->list_node);
130 if (retval != -EAGAIN) {
131 VLOG_WARN_RL(&rl, "%s: send error: %s",
132 rpc->name, strerror(-retval));
133 jsonrpc_error(rpc, -retval);
140 /* Arranges for the poll loop to wake up when 'rpc' needs to perform
141 * maintenance activities. */
143 jsonrpc_wait(struct jsonrpc *rpc)
146 stream_run_wait(rpc->stream);
147 if (!list_is_empty(&rpc->output)) {
148 stream_send_wait(rpc->stream);
154 * Returns the current status of 'rpc'. The possible return values are:
157 * - EOF: end of file (remote end closed connection; not necessarily an error).
159 * When this functions nonzero, 'rpc' is effectively out of commission. 'rpc'
160 * will not receive any more messages and any further messages that one
161 * attempts to send with 'rpc' will be discarded. The caller can keep 'rpc'
162 * around as long as it wants, but it's not going to provide any more useful
166 jsonrpc_get_status(const struct jsonrpc *rpc)
171 /* Returns the number of bytes buffered by 'rpc' to be written to the
172 * underlying stream. Always returns 0 if 'rpc' has encountered an error or if
173 * the remote end closed the connection. */
175 jsonrpc_get_backlog(const struct jsonrpc *rpc)
177 return rpc->status ? 0 : rpc->backlog;
180 /* Returns 'rpc''s name, that is, the name returned by stream_get_name() for
181 * the stream underlying 'rpc' when 'rpc' was created. */
183 jsonrpc_get_name(const struct jsonrpc *rpc)
189 jsonrpc_log_msg(const struct jsonrpc *rpc, const char *title,
190 const struct jsonrpc_msg *msg)
192 if (VLOG_IS_DBG_ENABLED()) {
193 struct ds s = DS_EMPTY_INITIALIZER;
195 ds_put_format(&s, ", method=\"%s\"", msg->method);
198 ds_put_cstr(&s, ", params=");
199 json_to_ds(msg->params, 0, &s);
202 ds_put_cstr(&s, ", result=");
203 json_to_ds(msg->result, 0, &s);
206 ds_put_cstr(&s, ", error=");
207 json_to_ds(msg->error, 0, &s);
210 ds_put_cstr(&s, ", id=");
211 json_to_ds(msg->id, 0, &s);
213 VLOG_DBG("%s: %s %s%s", rpc->name, title,
214 jsonrpc_msg_type_to_string(msg->type), ds_cstr(&s));
219 /* Schedules 'msg' to be sent on 'rpc' and returns 'rpc''s status (as with
220 * jsonrpc_get_status()).
222 * If 'msg' cannot be sent immediately, it is appended to a buffer. The caller
223 * is responsible for ensuring that the amount of buffered data is somehow
224 * limited. (jsonrpc_get_backlog() returns the amount of data currently
225 * buffered in 'rpc'.)
227 * Always takes ownership of 'msg', regardless of success. */
229 jsonrpc_send(struct jsonrpc *rpc, struct jsonrpc_msg *msg)
237 jsonrpc_msg_destroy(msg);
241 jsonrpc_log_msg(rpc, "send", msg);
243 json = jsonrpc_msg_to_json(msg);
244 s = json_to_string(json, 0);
248 buf = xmalloc(sizeof *buf);
249 ofpbuf_use(buf, s, length);
251 list_push_back(&rpc->output, &buf->list_node);
252 rpc->backlog += length;
254 if (rpc->backlog == length) {
260 /* Attempts to receive a message from 'rpc'.
262 * If successful, stores the received message in '*msgp' and returns 0. The
263 * caller takes ownership of '*msgp' and must eventually destroy it with
264 * jsonrpc_msg_destroy().
266 * Otherwise, stores NULL in '*msgp' and returns one of the following:
268 * - EAGAIN: No message has been received.
270 * - EOF: The remote end closed the connection gracefully.
272 * - Otherwise an errno value that represents a JSON-RPC protocol violation
273 * or another error fatal to the connection. 'rpc' will not send or
274 * receive any more messages.
277 jsonrpc_recv(struct jsonrpc *rpc, struct jsonrpc_msg **msgp)
284 while (!rpc->received) {
285 if (byteq_is_empty(&rpc->input)) {
289 chunk = byteq_headroom(&rpc->input);
290 retval = stream_recv(rpc->stream, byteq_head(&rpc->input), chunk);
292 if (retval == -EAGAIN) {
295 VLOG_WARN_RL(&rl, "%s: receive error: %s",
296 rpc->name, strerror(-retval));
297 jsonrpc_error(rpc, -retval);
300 } else if (retval == 0) {
301 jsonrpc_error(rpc, EOF);
304 byteq_advance_head(&rpc->input, retval);
309 rpc->parser = json_parser_create(0);
311 n = byteq_tailroom(&rpc->input);
312 used = json_parser_feed(rpc->parser,
313 (char *) byteq_tail(&rpc->input), n);
314 byteq_advance_tail(&rpc->input, used);
315 if (json_parser_is_done(rpc->parser)) {
316 jsonrpc_received(rpc);
318 const struct byteq *q = &rpc->input;
319 if (q->head <= BYTEQ_SIZE) {
320 stream_report_content(q->buffer, q->head,
322 THIS_MODULE, rpc->name);
330 *msgp = rpc->received;
331 rpc->received = NULL;
335 /* Causes the poll loop to wake up when jsonrpc_recv() may return a value other
338 jsonrpc_recv_wait(struct jsonrpc *rpc)
340 if (rpc->status || rpc->received || !byteq_is_empty(&rpc->input)) {
341 (poll_immediate_wake)(rpc->name);
343 stream_recv_wait(rpc->stream);
347 /* Sends 'msg' on 'rpc' and waits for it to be successfully queued to the
348 * underlying stream. Returns 0 if 'msg' was sent successfully, otherwise a
349 * status value (see jsonrpc_get_status()).
351 * Always takes ownership of 'msg', regardless of success. */
353 jsonrpc_send_block(struct jsonrpc *rpc, struct jsonrpc_msg *msg)
359 error = jsonrpc_send(rpc, msg);
366 if (list_is_empty(&rpc->output) || rpc->status) {
374 /* Waits for a message to be received on 'rpc'. Same semantics as
375 * jsonrpc_recv() except that EAGAIN will never be returned. */
377 jsonrpc_recv_block(struct jsonrpc *rpc, struct jsonrpc_msg **msgp)
380 int error = jsonrpc_recv(rpc, msgp);
381 if (error != EAGAIN) {
388 jsonrpc_recv_wait(rpc);
393 /* Sends 'request' to 'rpc' then waits for a reply. The return value is 0 if
394 * successful, in which case '*replyp' is set to the reply, which the caller
395 * must eventually free with jsonrpc_msg_destroy(). Otherwise returns a status
396 * value (see jsonrpc_get_status()).
398 * Discards any message received on 'rpc' that is not a reply to 'request'
399 * (based on message id).
401 * Always takes ownership of 'request', regardless of success. */
403 jsonrpc_transact_block(struct jsonrpc *rpc, struct jsonrpc_msg *request,
404 struct jsonrpc_msg **replyp)
406 struct jsonrpc_msg *reply = NULL;
410 id = json_clone(request->id);
411 error = jsonrpc_send_block(rpc, request);
414 error = jsonrpc_recv_block(rpc, &reply);
418 if ((reply->type == JSONRPC_REPLY || reply->type == JSONRPC_ERROR)
419 && json_equal(id, reply->id)) {
422 jsonrpc_msg_destroy(reply);
425 *replyp = error ? NULL : reply;
431 jsonrpc_received(struct jsonrpc *rpc)
433 struct jsonrpc_msg *msg;
437 json = json_parser_finish(rpc->parser);
439 if (json->type == JSON_STRING) {
440 VLOG_WARN_RL(&rl, "%s: error parsing stream: %s",
441 rpc->name, json_string(json));
442 jsonrpc_error(rpc, EPROTO);
447 error = jsonrpc_msg_from_json(json, &msg);
449 VLOG_WARN_RL(&rl, "%s: received bad JSON-RPC message: %s",
452 jsonrpc_error(rpc, EPROTO);
456 jsonrpc_log_msg(rpc, "received", msg);
461 jsonrpc_error(struct jsonrpc *rpc, int error)
466 jsonrpc_cleanup(rpc);
471 jsonrpc_cleanup(struct jsonrpc *rpc)
473 stream_close(rpc->stream);
476 json_parser_abort(rpc->parser);
479 jsonrpc_msg_destroy(rpc->received);
480 rpc->received = NULL;
482 ofpbuf_list_delete(&rpc->output);
486 static struct jsonrpc_msg *
487 jsonrpc_create(enum jsonrpc_msg_type type, const char *method,
488 struct json *params, struct json *result, struct json *error,
491 struct jsonrpc_msg *msg = xmalloc(sizeof *msg);
493 msg->method = method ? xstrdup(method) : NULL;
494 msg->params = params;
495 msg->result = result;
502 jsonrpc_create_id(void)
504 static unsigned int id;
505 return json_integer_create(id++);
509 jsonrpc_create_request(const char *method, struct json *params,
512 struct json *id = jsonrpc_create_id();
514 *idp = json_clone(id);
516 return jsonrpc_create(JSONRPC_REQUEST, method, params, NULL, NULL, id);
520 jsonrpc_create_notify(const char *method, struct json *params)
522 return jsonrpc_create(JSONRPC_NOTIFY, method, params, NULL, NULL, NULL);
526 jsonrpc_create_reply(struct json *result, const struct json *id)
528 return jsonrpc_create(JSONRPC_REPLY, NULL, NULL, result, NULL,
533 jsonrpc_create_error(struct json *error, const struct json *id)
535 return jsonrpc_create(JSONRPC_REPLY, NULL, NULL, NULL, error,
540 jsonrpc_msg_type_to_string(enum jsonrpc_msg_type type)
543 case JSONRPC_REQUEST:
547 return "notification";
559 jsonrpc_msg_is_valid(const struct jsonrpc_msg *m)
561 const char *type_name;
562 unsigned int pattern;
564 if (m->params && m->params->type != JSON_ARRAY) {
565 return xstrdup("\"params\" must be JSON array");
569 case JSONRPC_REQUEST:
586 return xasprintf("invalid JSON-RPC message type %d", m->type);
589 type_name = jsonrpc_msg_type_to_string(m->type);
590 if ((m->method != NULL) != ((pattern & 0x10000) != 0)) {
591 return xasprintf("%s must%s have \"method\"",
592 type_name, (pattern & 0x10000) ? "" : " not");
595 if ((m->params != NULL) != ((pattern & 0x1000) != 0)) {
596 return xasprintf("%s must%s have \"params\"",
597 type_name, (pattern & 0x1000) ? "" : " not");
600 if ((m->result != NULL) != ((pattern & 0x100) != 0)) {
601 return xasprintf("%s must%s have \"result\"",
602 type_name, (pattern & 0x100) ? "" : " not");
605 if ((m->error != NULL) != ((pattern & 0x10) != 0)) {
606 return xasprintf("%s must%s have \"error\"",
607 type_name, (pattern & 0x10) ? "" : " not");
610 if ((m->id != NULL) != ((pattern & 0x1) != 0)) {
611 return xasprintf("%s must%s have \"id\"",
612 type_name, (pattern & 0x1) ? "" : " not");
619 jsonrpc_msg_destroy(struct jsonrpc_msg *m)
623 json_destroy(m->params);
624 json_destroy(m->result);
625 json_destroy(m->error);
632 null_from_json_null(struct json *json)
634 if (json && json->type == JSON_NULL) {
642 jsonrpc_msg_from_json(struct json *json, struct jsonrpc_msg **msgp)
644 struct json *method = NULL;
645 struct jsonrpc_msg *msg = NULL;
646 struct shash *object;
649 if (json->type != JSON_OBJECT) {
650 error = xstrdup("message is not a JSON object");
653 object = json_object(json);
655 method = shash_find_and_delete(object, "method");
656 if (method && method->type != JSON_STRING) {
657 error = xstrdup("method is not a JSON string");
661 msg = xzalloc(sizeof *msg);
662 msg->method = method ? xstrdup(method->u.string) : NULL;
663 msg->params = null_from_json_null(shash_find_and_delete(object, "params"));
664 msg->result = null_from_json_null(shash_find_and_delete(object, "result"));
665 msg->error = null_from_json_null(shash_find_and_delete(object, "error"));
666 msg->id = null_from_json_null(shash_find_and_delete(object, "id"));
667 msg->type = (msg->result ? JSONRPC_REPLY
668 : msg->error ? JSONRPC_ERROR
669 : msg->id ? JSONRPC_REQUEST
671 if (!shash_is_empty(object)) {
672 error = xasprintf("message has unexpected member \"%s\"",
673 shash_first(object)->name);
676 error = jsonrpc_msg_is_valid(msg);
682 json_destroy(method);
685 jsonrpc_msg_destroy(msg);
693 jsonrpc_msg_to_json(struct jsonrpc_msg *m)
695 struct json *json = json_object_create();
698 json_object_put(json, "method", json_string_create_nocopy(m->method));
702 json_object_put(json, "params", m->params);
706 json_object_put(json, "result", m->result);
707 } else if (m->type == JSONRPC_ERROR) {
708 json_object_put(json, "result", json_null_create());
712 json_object_put(json, "error", m->error);
713 } else if (m->type == JSONRPC_REPLY) {
714 json_object_put(json, "error", json_null_create());
718 json_object_put(json, "id", m->id);
719 } else if (m->type == JSONRPC_NOTIFY) {
720 json_object_put(json, "id", json_null_create());
728 /* A JSON-RPC session with reconnection. */
730 struct jsonrpc_session {
731 struct reconnect *reconnect;
733 struct stream *stream;
734 struct pstream *pstream;
738 /* Creates and returns a jsonrpc_session to 'name', which should be a string
739 * acceptable to stream_open() or pstream_open().
741 * If 'name' is an active connection method, e.g. "tcp:127.1.2.3", the new
742 * jsonrpc_session connects and reconnects, with back-off, to 'name'.
744 * If 'name' is a passive connection method, e.g. "ptcp:", the new
745 * jsonrpc_session listens for connections to 'name'. It maintains at most one
746 * connection at any given time. Any new connection causes the previous one
747 * (if any) to be dropped. */
748 struct jsonrpc_session *
749 jsonrpc_session_open(const char *name)
751 struct jsonrpc_session *s;
753 s = xmalloc(sizeof *s);
754 s->reconnect = reconnect_create(time_msec());
755 reconnect_set_name(s->reconnect, name);
756 reconnect_enable(s->reconnect, time_msec());
762 if (!pstream_verify_name(name)) {
763 reconnect_set_passive(s->reconnect, true, time_msec());
769 /* Creates and returns a jsonrpc_session that is initially connected to
770 * 'jsonrpc'. If the connection is dropped, it will not be reconnected.
772 * On the assumption that such connections are likely to be short-lived
773 * (e.g. from ovs-vsctl), informational logging for them is suppressed. */
774 struct jsonrpc_session *
775 jsonrpc_session_open_unreliably(struct jsonrpc *jsonrpc)
777 struct jsonrpc_session *s;
779 s = xmalloc(sizeof *s);
780 s->reconnect = reconnect_create(time_msec());
781 reconnect_set_quiet(s->reconnect, true);
782 reconnect_set_name(s->reconnect, jsonrpc_get_name(jsonrpc));
783 reconnect_set_max_tries(s->reconnect, 0);
784 reconnect_connected(s->reconnect, time_msec());
794 jsonrpc_session_close(struct jsonrpc_session *s)
797 jsonrpc_close(s->rpc);
798 reconnect_destroy(s->reconnect);
799 stream_close(s->stream);
800 pstream_close(s->pstream);
806 jsonrpc_session_disconnect(struct jsonrpc_session *s)
809 jsonrpc_error(s->rpc, EOF);
810 jsonrpc_close(s->rpc);
813 } else if (s->stream) {
814 stream_close(s->stream);
821 jsonrpc_session_connect(struct jsonrpc_session *s)
823 const char *name = reconnect_get_name(s->reconnect);
826 jsonrpc_session_disconnect(s);
827 if (!reconnect_is_passive(s->reconnect)) {
828 error = jsonrpc_stream_open(name, &s->stream);
830 reconnect_connecting(s->reconnect, time_msec());
833 error = s->pstream ? 0 : jsonrpc_pstream_open(name, &s->pstream);
835 reconnect_listening(s->reconnect, time_msec());
840 reconnect_connect_failed(s->reconnect, time_msec(), error);
846 jsonrpc_session_run(struct jsonrpc_session *s)
849 struct stream *stream;
852 error = pstream_accept(s->pstream, &stream);
854 if (s->rpc || s->stream) {
856 "%s: new connection replacing active connection",
857 reconnect_get_name(s->reconnect));
858 jsonrpc_session_disconnect(s);
860 reconnect_connected(s->reconnect, time_msec());
861 s->rpc = jsonrpc_open(stream);
862 } else if (error != EAGAIN) {
863 reconnect_listen_error(s->reconnect, time_msec(), error);
864 pstream_close(s->pstream);
873 error = jsonrpc_get_status(s->rpc);
875 reconnect_disconnected(s->reconnect, time_msec(), error);
876 jsonrpc_session_disconnect(s);
878 } else if (s->stream) {
881 stream_run(s->stream);
882 error = stream_connect(s->stream);
884 reconnect_connected(s->reconnect, time_msec());
885 s->rpc = jsonrpc_open(s->stream);
887 } else if (error != EAGAIN) {
888 reconnect_connect_failed(s->reconnect, time_msec(), error);
889 stream_close(s->stream);
894 switch (reconnect_run(s->reconnect, time_msec())) {
895 case RECONNECT_CONNECT:
896 jsonrpc_session_connect(s);
899 case RECONNECT_DISCONNECT:
900 reconnect_disconnected(s->reconnect, time_msec(), 0);
901 jsonrpc_session_disconnect(s);
904 case RECONNECT_PROBE:
907 struct jsonrpc_msg *request;
909 params = json_array_create_empty();
910 request = jsonrpc_create_request("echo", params, NULL);
911 json_destroy(request->id);
912 request->id = json_string_create("echo");
913 jsonrpc_send(s->rpc, request);
920 jsonrpc_session_wait(struct jsonrpc_session *s)
923 jsonrpc_wait(s->rpc);
924 } else if (s->stream) {
925 stream_run_wait(s->stream);
926 stream_connect_wait(s->stream);
929 pstream_wait(s->pstream);
931 reconnect_wait(s->reconnect, time_msec());
935 jsonrpc_session_get_backlog(const struct jsonrpc_session *s)
937 return s->rpc ? jsonrpc_get_backlog(s->rpc) : 0;
940 /* Always returns a pointer to a valid C string, assuming 's' was initialized
943 jsonrpc_session_get_name(const struct jsonrpc_session *s)
945 return reconnect_get_name(s->reconnect);
948 /* Always takes ownership of 'msg', regardless of success. */
950 jsonrpc_session_send(struct jsonrpc_session *s, struct jsonrpc_msg *msg)
953 return jsonrpc_send(s->rpc, msg);
955 jsonrpc_msg_destroy(msg);
961 jsonrpc_session_recv(struct jsonrpc_session *s)
964 struct jsonrpc_msg *msg;
965 jsonrpc_recv(s->rpc, &msg);
967 reconnect_received(s->reconnect, time_msec());
968 if (msg->type == JSONRPC_REQUEST && !strcmp(msg->method, "echo")) {
969 /* Echo request. Send reply. */
970 struct jsonrpc_msg *reply;
972 reply = jsonrpc_create_reply(json_clone(msg->params), msg->id);
973 jsonrpc_session_send(s, reply);
974 } else if (msg->type == JSONRPC_REPLY
975 && msg->id && msg->id->type == JSON_STRING
976 && !strcmp(msg->id->u.string, "echo")) {
977 /* It's a reply to our echo request. Suppress it. */
981 jsonrpc_msg_destroy(msg);
988 jsonrpc_session_recv_wait(struct jsonrpc_session *s)
991 jsonrpc_recv_wait(s->rpc);
996 jsonrpc_session_is_alive(const struct jsonrpc_session *s)
998 return s->rpc || s->stream || reconnect_get_max_tries(s->reconnect);
1002 jsonrpc_session_is_connected(const struct jsonrpc_session *s)
1004 return s->rpc != NULL;
1008 jsonrpc_session_get_seqno(const struct jsonrpc_session *s)
1014 jsonrpc_session_get_status(const struct jsonrpc_session *s)
1016 return s && s->rpc ? jsonrpc_get_status(s->rpc) : 0;
1020 jsonrpc_session_get_reconnect_stats(const struct jsonrpc_session *s,
1021 struct reconnect_stats *stats)
1023 reconnect_get_stats(s->reconnect, time_msec(), stats);
1027 jsonrpc_session_force_reconnect(struct jsonrpc_session *s)
1029 reconnect_force_reconnect(s->reconnect, time_msec());
1033 jsonrpc_session_set_max_backoff(struct jsonrpc_session *s, int max_backoff)
1035 reconnect_set_backoff(s->reconnect, 0, max_backoff);
1039 jsonrpc_session_set_probe_interval(struct jsonrpc_session *s,
1042 reconnect_set_probe_interval(s->reconnect, probe_interval);