ovs-vsctl: Try connecting only once for active connections by default.
[sliver-openvswitch.git] / lib / jsonrpc.c
index 7646771..1ea5398 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2010, 2011, 2012 Nicira Networks.
+ * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,6 @@
 
 #include "jsonrpc.h"
 
-#include <assert.h>
 #include <errno.h>
 
 #include "byteq.h"
@@ -60,19 +59,20 @@ static void jsonrpc_error(struct jsonrpc *, int error);
 /* This is just the same as stream_open() except that it uses the default
  * JSONRPC ports if none is specified. */
 int
-jsonrpc_stream_open(const char *name, struct stream **streamp)
+jsonrpc_stream_open(const char *name, struct stream **streamp, uint8_t dscp)
 {
     return stream_open_with_default_ports(name, JSONRPC_TCP_PORT,
-                                          JSONRPC_SSL_PORT, streamp);
+                                          JSONRPC_SSL_PORT, streamp,
+                                          dscp);
 }
 
 /* This is just the same as pstream_open() except that it uses the default
  * JSONRPC ports if none is specified. */
 int
-jsonrpc_pstream_open(const char *name, struct pstream **pstreamp)
+jsonrpc_pstream_open(const char *name, struct pstream **pstreamp, uint8_t dscp)
 {
     return pstream_open_with_default_ports(name, JSONRPC_TCP_PORT,
-                                           JSONRPC_SSL_PORT, pstreamp);
+                                           JSONRPC_SSL_PORT, pstreamp, dscp);
 }
 
 /* Returns a new JSON-RPC stream that uses 'stream' for input and output.  The
@@ -82,7 +82,7 @@ jsonrpc_open(struct stream *stream)
 {
     struct jsonrpc *rpc;
 
-    assert(stream != NULL);
+    ovs_assert(stream != NULL);
 
     rpc = xzalloc(sizeof *rpc);
     rpc->name = xstrdup(stream_get_name(stream));
@@ -177,6 +177,14 @@ jsonrpc_get_backlog(const struct jsonrpc *rpc)
     return rpc->status ? 0 : rpc->backlog;
 }
 
+/* Returns the number of bytes that have been received on 'rpc''s underlying
+ * stream.  (The value wraps around if it exceeds UINT_MAX.) */
+unsigned int
+jsonrpc_get_received_bytes(const struct jsonrpc *rpc)
+{
+    return rpc->input.head;
+}
+
 /* Returns 'rpc''s name, that is, the name returned by stream_get_name() for
  * the stream underlying 'rpc' when 'rpc' was created. */
 const char *
@@ -276,13 +284,19 @@ jsonrpc_send(struct jsonrpc *rpc, struct jsonrpc_msg *msg)
 int
 jsonrpc_recv(struct jsonrpc *rpc, struct jsonrpc_msg **msgp)
 {
+    int i;
+
     *msgp = NULL;
     if (rpc->status) {
         return rpc->status;
     }
 
-    while (!rpc->received) {
-        if (byteq_is_empty(&rpc->input)) {
+    for (i = 0; i < 50; i++) {
+        if (rpc->received) {
+            *msgp = rpc->received;
+            rpc->received = NULL;
+            return 0;
+        } else if (byteq_is_empty(&rpc->input)) {
             size_t chunk;
             int retval;
 
@@ -327,9 +341,7 @@ jsonrpc_recv(struct jsonrpc *rpc, struct jsonrpc_msg **msgp)
         }
     }
 
-    *msgp = rpc->received;
-    rpc->received = NULL;
-    return 0;
+    return EAGAIN;
 }
 
 /* Causes the poll loop to wake up when jsonrpc_recv() may return a value other
@@ -412,9 +424,11 @@ jsonrpc_transact_block(struct jsonrpc *rpc, struct jsonrpc_msg *request,
     if (!error) {
         for (;;) {
             error = jsonrpc_recv_block(rpc, &reply);
-            if (error
-                || (reply->type == JSONRPC_REPLY
-                    && json_equal(id, reply->id))) {
+            if (error) {
+                break;
+            }
+            if ((reply->type == JSONRPC_REPLY || reply->type == JSONRPC_ERROR)
+                && json_equal(id, reply->id)) {
                 break;
             }
             jsonrpc_msg_destroy(reply);
@@ -458,7 +472,7 @@ jsonrpc_received(struct jsonrpc *rpc)
 static void
 jsonrpc_error(struct jsonrpc *rpc, int error)
 {
-    assert(error);
+    ovs_assert(error);
     if (!rpc->status) {
         rpc->status = error;
         jsonrpc_cleanup(rpc);
@@ -730,21 +744,27 @@ struct jsonrpc_session {
     struct jsonrpc *rpc;
     struct stream *stream;
     struct pstream *pstream;
+    int last_error;
     unsigned int seqno;
+    uint8_t dscp;
 };
 
 /* Creates and returns a jsonrpc_session to 'name', which should be a string
  * acceptable to stream_open() or pstream_open().
  *
  * If 'name' is an active connection method, e.g. "tcp:127.1.2.3", the new
- * jsonrpc_session connects and reconnects, with back-off, to 'name'.
+ * jsonrpc_session connects to 'name'.  If 'retry' is true, then the new
+ * session connects and reconnects to 'name', with backoff.  If 'retry' is
+ * false, the new session will only try to connect once and after a connection
+ * failure or a disconnection jsonrpc_session_is_alive() will return false for
+ * the new session.
  *
  * If 'name' is a passive connection method, e.g. "ptcp:", the new
  * jsonrpc_session listens for connections to 'name'.  It maintains at most one
  * connection at any given time.  Any new connection causes the previous one
  * (if any) to be dropped. */
 struct jsonrpc_session *
-jsonrpc_session_open(const char *name)
+jsonrpc_session_open(const char *name, bool retry)
 {
     struct jsonrpc_session *s;
 
@@ -756,9 +776,18 @@ jsonrpc_session_open(const char *name)
     s->stream = NULL;
     s->pstream = NULL;
     s->seqno = 0;
+    s->dscp = 0;
+    s->last_error = 0;
 
     if (!pstream_verify_name(name)) {
         reconnect_set_passive(s->reconnect, true, time_msec());
+    } else if (!retry) {
+        reconnect_set_max_tries(s->reconnect, 1);
+        reconnect_set_backoff(s->reconnect, INT_MAX, INT_MAX);
+    }
+
+    if (!stream_or_pstream_needs_probes(name)) {
+        reconnect_set_probe_interval(s->reconnect, 0);
     }
 
     return s;
@@ -770,7 +799,7 @@ jsonrpc_session_open(const char *name)
  * On the assumption that such connections are likely to be short-lived
  * (e.g. from ovs-vsctl), informational logging for them is suppressed. */
 struct jsonrpc_session *
-jsonrpc_session_open_unreliably(struct jsonrpc *jsonrpc)
+jsonrpc_session_open_unreliably(struct jsonrpc *jsonrpc, uint8_t dscp)
 {
     struct jsonrpc_session *s;
 
@@ -780,6 +809,7 @@ jsonrpc_session_open_unreliably(struct jsonrpc *jsonrpc)
     reconnect_set_name(s->reconnect, jsonrpc_get_name(jsonrpc));
     reconnect_set_max_tries(s->reconnect, 0);
     reconnect_connected(s->reconnect, time_msec());
+    s->dscp = dscp;
     s->rpc = jsonrpc;
     s->stream = NULL;
     s->pstream = NULL;
@@ -823,12 +853,15 @@ jsonrpc_session_connect(struct jsonrpc_session *s)
 
     jsonrpc_session_disconnect(s);
     if (!reconnect_is_passive(s->reconnect)) {
-        error = jsonrpc_stream_open(name, &s->stream);
+        error = jsonrpc_stream_open(name, &s->stream, s->dscp);
         if (!error) {
             reconnect_connecting(s->reconnect, time_msec());
+        } else {
+            s->last_error = error;
         }
     } else {
-        error = s->pstream ? 0 : jsonrpc_pstream_open(name, &s->pstream);
+        error = s->pstream ? 0 : jsonrpc_pstream_open(name, &s->pstream,
+                                                      s->dscp);
         if (!error) {
             reconnect_listening(s->reconnect, time_msec());
         }
@@ -865,13 +898,28 @@ jsonrpc_session_run(struct jsonrpc_session *s)
     }
 
     if (s->rpc) {
+        size_t backlog;
         int error;
 
+        backlog = jsonrpc_get_backlog(s->rpc);
         jsonrpc_run(s->rpc);
+        if (jsonrpc_get_backlog(s->rpc) < backlog) {
+            /* Data previously caught in a queue was successfully sent (or
+             * there's an error, which we'll catch below.)
+             *
+             * We don't count data that is successfully sent immediately as
+             * activity, because there's a lot of queuing downstream from us,
+             * which means that we can push a lot of data into a connection
+             * that has stalled and won't ever recover.
+             */
+            reconnect_activity(s->reconnect, time_msec());
+        }
+
         error = jsonrpc_get_status(s->rpc);
         if (error) {
             reconnect_disconnected(s->reconnect, time_msec(), error);
             jsonrpc_session_disconnect(s);
+            s->last_error = error;
         }
     } else if (s->stream) {
         int error;
@@ -959,10 +1007,21 @@ struct jsonrpc_msg *
 jsonrpc_session_recv(struct jsonrpc_session *s)
 {
     if (s->rpc) {
+        unsigned int received_bytes;
         struct jsonrpc_msg *msg;
+
+        received_bytes = jsonrpc_get_received_bytes(s->rpc);
         jsonrpc_recv(s->rpc, &msg);
+        if (received_bytes != jsonrpc_get_received_bytes(s->rpc)) {
+            /* Data was successfully received.
+             *
+             * Previously we only counted receiving a full message as activity,
+             * but with large messages or a slow connection that policy could
+             * time out the session mid-message. */
+            reconnect_activity(s->reconnect, time_msec());
+        }
+
         if (msg) {
-            reconnect_received(s->reconnect, time_msec());
             if (msg->type == JSONRPC_REQUEST && !strcmp(msg->method, "echo")) {
                 /* Echo request.  Send reply. */
                 struct jsonrpc_msg *reply;
@@ -1014,6 +1073,12 @@ jsonrpc_session_get_status(const struct jsonrpc_session *s)
     return s && s->rpc ? jsonrpc_get_status(s->rpc) : 0;
 }
 
+int
+jsonrpc_session_get_last_error(const struct jsonrpc_session *s)
+{
+    return s->last_error;
+}
+
 void
 jsonrpc_session_get_reconnect_stats(const struct jsonrpc_session *s,
                                     struct reconnect_stats *stats)
@@ -1039,3 +1104,27 @@ jsonrpc_session_set_probe_interval(struct jsonrpc_session *s,
 {
     reconnect_set_probe_interval(s->reconnect, probe_interval);
 }
+
+void
+jsonrpc_session_set_dscp(struct jsonrpc_session *s,
+                         uint8_t dscp)
+{
+    if (s->dscp != dscp) {
+        if (s->pstream) {
+            int error;
+
+            error = pstream_set_dscp(s->pstream, dscp);
+            if (error) {
+                VLOG_ERR("%s: failed set_dscp %s",
+                         reconnect_get_name(s->reconnect), strerror(error));
+            }
+            /*
+             * XXX race window between setting dscp to listening socket
+             * and accepting socket. accepted socket may have old dscp value.
+             * Ignore this race window for now.
+             */
+        }
+        s->dscp = dscp;
+        jsonrpc_session_force_reconnect(s);
+    }
+}