From: Ben Pfaff <blp@nicira.com>
Date: Thu, 17 Dec 2009 23:16:43 +0000 (-0800)
Subject: ovsdb-server: Factor out complication by using jsonrpc_session.
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4931f33ad9e25eb2df70ff20f1eeb4df813f8b2c;p=openvswitch

ovsdb-server: Factor out complication by using jsonrpc_session.
---

diff --git a/lib/jsonrpc.c b/lib/jsonrpc.c
index bd019f73..0f535155 100644
--- a/lib/jsonrpc.c
+++ b/lib/jsonrpc.c
@@ -630,6 +630,9 @@ struct jsonrpc_session {
     unsigned int seqno;
 };
 
+/* Creates and returns a jsonrpc_session that connects and reconnects, with
+ * back-off, to 'name', which should be a string acceptable to
+ * stream_open(). */
 struct jsonrpc_session *
 jsonrpc_session_open(const char *name)
 {
@@ -646,6 +649,25 @@ jsonrpc_session_open(const char *name)
     return s;
 }
 
+/* Creates and returns a jsonrpc_session that is initially connected to
+ * 'jsonrpc'.  If the connection is dropped, it will not be reconnected. */
+struct jsonrpc_session *
+jsonrpc_session_open_unreliably(struct jsonrpc *jsonrpc)
+{
+    struct jsonrpc_session *s;
+
+    s = xmalloc(sizeof *s);
+    s->reconnect = reconnect_create(time_msec());
+    reconnect_set_name(s->reconnect, jsonrpc_get_name(jsonrpc));
+    reconnect_set_max_tries(s->reconnect, 0);
+    reconnect_connected(s->reconnect, time_msec());
+    s->rpc = jsonrpc;
+    s->stream = NULL;
+    s->seqno = 0;
+
+    return s;
+}
+
 void
 jsonrpc_session_close(struct jsonrpc_session *s)
 {
@@ -767,14 +789,28 @@ jsonrpc_session_send(struct jsonrpc_session *s, struct jsonrpc_msg *msg)
 struct jsonrpc_msg *
 jsonrpc_session_recv(struct jsonrpc_session *s)
 {
-    struct jsonrpc_msg *msg = NULL;
     if (s->rpc) {
+        struct jsonrpc_msg *msg;
         jsonrpc_recv(s->rpc, &msg);
         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;
+
+                reply = jsonrpc_create_reply(json_clone(msg->params), msg->id);
+                jsonrpc_session_send(s, reply);
+            } else if (msg->type == JSONRPC_REPLY
+                && msg->id && msg->id->type == JSON_STRING
+                && !strcmp(msg->id->u.string, "echo")) {
+                /* It's a reply to our echo request.  Suppress it. */
+            } else {
+                return msg;
+            }
+            jsonrpc_msg_destroy(msg);
         }
     }
-    return msg;
+    return NULL;
 }
 
 void
@@ -785,6 +821,12 @@ jsonrpc_session_recv_wait(struct jsonrpc_session *s)
     }
 }
 
+bool
+jsonrpc_session_is_alive(const struct jsonrpc_session *s)
+{
+    return s->rpc || s->stream || reconnect_get_max_tries(s->reconnect);
+}
+
 bool
 jsonrpc_session_is_connected(const struct jsonrpc_session *s)
 {
diff --git a/lib/jsonrpc.h b/lib/jsonrpc.h
index 93ac2e86..ae8b9de3 100644
--- a/lib/jsonrpc.h
+++ b/lib/jsonrpc.h
@@ -86,6 +86,7 @@ struct json *jsonrpc_msg_to_json(struct jsonrpc_msg *);
 /* A JSON-RPC session with reconnection. */
 
 struct jsonrpc_session *jsonrpc_session_open(const char *name);
+struct jsonrpc_session *jsonrpc_session_open_unreliably(struct jsonrpc *);
 void jsonrpc_session_close(struct jsonrpc_session *);
 
 void jsonrpc_session_run(struct jsonrpc_session *);
@@ -98,6 +99,7 @@ int jsonrpc_session_send(struct jsonrpc_session *, struct jsonrpc_msg *);
 struct jsonrpc_msg *jsonrpc_session_recv(struct jsonrpc_session *);
 void jsonrpc_session_recv_wait(struct jsonrpc_session *);
 
+bool jsonrpc_session_is_alive(const struct jsonrpc_session *);
 bool jsonrpc_session_is_connected(const struct jsonrpc_session *);
 unsigned int jsonrpc_session_get_seqno(const struct jsonrpc_session *);
 void jsonrpc_session_force_reconnect(struct jsonrpc_session *);
diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c
index 877fa3e2..29d1d0c4 100644
--- a/lib/ovsdb-idl.c
+++ b/lib/ovsdb-idl.c
@@ -244,9 +244,7 @@ ovsdb_idl_run(struct ovsdb_idl *idl)
         }
 
         reply = NULL;
-        if (msg->type == JSONRPC_REQUEST && !strcmp(msg->method, "echo")) {
-            reply = jsonrpc_create_reply(json_clone(msg->params), msg->id);
-        } else if (msg->type == JSONRPC_NOTIFY
+        if (msg->type == JSONRPC_NOTIFY
                    && !strcmp(msg->method, "update")
                    && msg->params->type == JSON_ARRAY
                    && msg->params->u.array.n == 2
diff --git a/ovsdb/jsonrpc-server.c b/ovsdb/jsonrpc-server.c
index a8e724a2..0bf11378 100644
--- a/ovsdb/jsonrpc-server.c
+++ b/ovsdb/jsonrpc-server.c
@@ -160,15 +160,12 @@ struct ovsdb_jsonrpc_session {
     /* Monitors. */
     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 
-    /* Connecting and reconnecting. */
-    struct reconnect *reconnect; /* For back-off. */
-    bool active;                /* Active or passive connection? */
-    struct jsonrpc *rpc;
-    struct stream *stream;      /* Only if active == false and rpc == NULL. */
+    /* Network connectivity. */
+    struct jsonrpc_session *js;  /* JSON-RPC session. */
+    unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 };
 
 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
-static void ovsdb_jsonrpc_session_disconnect(struct ovsdb_jsonrpc_session *s);
 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
@@ -178,7 +175,7 @@ static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 
 static struct ovsdb_jsonrpc_session *
 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_server *svr,
-                             const char *name, bool active)
+                             struct jsonrpc_session *js)
 {
     struct ovsdb_jsonrpc_session *s;
 
@@ -188,10 +185,8 @@ ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_server *svr,
     hmap_init(&s->triggers);
     hmap_init(&s->monitors);
     list_init(&s->completions);
-    s->reconnect = reconnect_create(time_msec());
-    reconnect_set_name(s->reconnect, name);
-    reconnect_enable(s->reconnect, time_msec());
-    s->active = active;
+    s->js = js;
+    s->js_seqno = jsonrpc_session_get_seqno(js);
 
     svr->n_sessions++;
 
@@ -202,132 +197,54 @@ static void
 ovsdb_jsonrpc_session_create_active(struct ovsdb_jsonrpc_server *svr,
                                     const char *name)
 {
-    ovsdb_jsonrpc_session_create(svr, name, true);
+    ovsdb_jsonrpc_session_create(svr, jsonrpc_session_open(name));
 }
 
 static void
 ovsdb_jsonrpc_session_create_passive(struct ovsdb_jsonrpc_server *svr,
                                      struct stream *stream)
 {
-    struct ovsdb_jsonrpc_session *s;
-
-    s = ovsdb_jsonrpc_session_create(svr, stream_get_name(stream), false);
-    reconnect_connected(s->reconnect, time_msec());
-    s->rpc = jsonrpc_open(stream);
+    ovsdb_jsonrpc_session_create(
+        svr, jsonrpc_session_open_unreliably(jsonrpc_open(stream)));
 }
 
 static void
 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 {
-    ovsdb_jsonrpc_session_disconnect(s);
+    jsonrpc_session_close(s->js);
     list_remove(&s->node);
     s->server->n_sessions--;
 }
 
-static void
-ovsdb_jsonrpc_session_disconnect(struct ovsdb_jsonrpc_session *s)
+static int
+ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 {
-    reconnect_disconnected(s->reconnect, time_msec(), 0);
-    if (s->rpc) {
-        jsonrpc_error(s->rpc, EOF);
+    jsonrpc_session_run(s->js);
+    if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
+        s->js_seqno = jsonrpc_session_get_seqno(s->js);
         ovsdb_jsonrpc_trigger_complete_all(s);
         ovsdb_jsonrpc_monitor_remove_all(s);
-        jsonrpc_close(s->rpc);
-        s->rpc = NULL;
-    } else if (s->stream) {
-        stream_close(s->stream);
-        s->stream = NULL;
     }
-}
 
-static void
-ovsdb_jsonrpc_session_connect(struct ovsdb_jsonrpc_session *s)
-{
-    ovsdb_jsonrpc_session_disconnect(s);
-    if (s->active) {
-        int error = stream_open(reconnect_get_name(s->reconnect), &s->stream);
-        if (error) {
-            reconnect_connect_failed(s->reconnect, time_msec(), error);
-        } else {
-            reconnect_connecting(s->reconnect, time_msec());
-        }
-    }
-}
-
-static int
-ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
-{
-    if (s->rpc) {
-        struct jsonrpc_msg *msg;
-        int error;
+    ovsdb_jsonrpc_trigger_complete_done(s);
 
-        jsonrpc_run(s->rpc);
-
-        ovsdb_jsonrpc_trigger_complete_done(s);
-
-        if (!jsonrpc_get_backlog(s->rpc) && !jsonrpc_recv(s->rpc, &msg)) {
-            reconnect_received(s->reconnect, time_msec());
+    if (!jsonrpc_session_get_backlog(s->js)) {
+        struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js);
+        if (msg) {
             if (msg->type == JSONRPC_REQUEST) {
                 ovsdb_jsonrpc_session_got_request(s, msg);
             } else if (msg->type == JSONRPC_NOTIFY) {
                 ovsdb_jsonrpc_session_got_notify(s, msg);
-            } else if (msg->type == JSONRPC_REPLY
-                       && msg->id && msg->id->type == JSON_STRING
-                       && !strcmp(msg->id->u.string, "echo")) {
-                /* It's a reply to our echo request.  Ignore it. */
             } else {
                 VLOG_WARN("%s: received unexpected %s message",
-                          jsonrpc_get_name(s->rpc),
+                          jsonrpc_session_get_name(s->js),
                           jsonrpc_msg_type_to_string(msg->type));
-                jsonrpc_error(s->rpc, EPROTO);
+                jsonrpc_session_force_reconnect(s->js);
                 jsonrpc_msg_destroy(msg);
             }
         }
-
-        error = jsonrpc_get_status(s->rpc);
-        if (error) {
-            if (s->active) {
-                ovsdb_jsonrpc_session_disconnect(s);
-            } else {
-                return error;
-            }
-        }
-    } else if (s->stream) {
-        int error = stream_connect(s->stream);
-        if (!error) {
-            reconnect_connected(s->reconnect, time_msec());
-            s->rpc = jsonrpc_open(s->stream);
-            s->stream = NULL;
-        } else if (error != EAGAIN) {
-            reconnect_connect_failed(s->reconnect, time_msec(), error);
-            stream_close(s->stream);
-            s->stream = NULL;
-        }
     }
-
-    switch (reconnect_run(s->reconnect, time_msec())) {
-    case RECONNECT_CONNECT:
-        ovsdb_jsonrpc_session_connect(s);
-        break;
-
-    case RECONNECT_DISCONNECT:
-        ovsdb_jsonrpc_session_disconnect(s);
-        break;
-
-    case RECONNECT_PROBE:
-        if (s->rpc) {
-            struct json *params;
-            struct jsonrpc_msg *request;
-
-            params = json_array_create_empty();
-            request = jsonrpc_create_request("echo", params, NULL);
-            json_destroy(request->id);
-            request->id = json_string_create("echo");
-            jsonrpc_send(s->rpc, request);
-        }
-        break;
-    }
-    return s->active || s->rpc ? 0 : ETIMEDOUT;
+    return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 }
 
 static void
@@ -347,15 +264,10 @@ ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_server *svr)
 static void
 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 {
-    if (s->rpc) {
-        jsonrpc_wait(s->rpc);
-        if (!jsonrpc_get_backlog(s->rpc)) {
-            jsonrpc_recv_wait(s->rpc);
-        }
-    } else if (s->stream) {
-        stream_connect_wait(s->stream);
+    jsonrpc_session_wait(s->js);
+    if (!jsonrpc_session_get_backlog(s->js)) {
+        jsonrpc_session_recv_wait(s->js);
     }
-    reconnect_wait(s->reconnect, time_msec());
 }
 
 static void
@@ -404,7 +316,7 @@ ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 
     if (reply) {
         jsonrpc_msg_destroy(request);
-        jsonrpc_send(s->rpc, reply);
+        jsonrpc_session_send(s->js, reply);
     }
 }
 
@@ -456,8 +368,11 @@ ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s,
     hash = json_hash(id, 0);
     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
     if (t) {
-        jsonrpc_send(s->rpc, jsonrpc_create_error(
-                         json_string_create("duplicate request ID"), id));
+        struct jsonrpc_msg *msg;
+
+        msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
+                                   id);
+        jsonrpc_session_send(s->js, msg);
         json_destroy(id);
         json_destroy(params);
         return;
@@ -499,7 +414,7 @@ ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 {
     struct ovsdb_jsonrpc_session *s = t->session;
 
-    if (s->rpc && !jsonrpc_get_status(s->rpc)) {
+    if (jsonrpc_session_is_connected(s->js)) {
         struct jsonrpc_msg *reply;
         struct json *result;
 
@@ -510,7 +425,7 @@ ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
             reply = jsonrpc_create_error(json_string_create("canceled"),
                                          t->id);
         }
-        jsonrpc_send(s->rpc, reply);
+        jsonrpc_session_send(s->js, reply);
     }
 
     json_destroy(t->id);
@@ -891,7 +806,7 @@ ovsdb_jsonrpc_monitor_commit(struct ovsdb_replica *replica,
         params = json_array_create_2(json_clone(aux.monitor->monitor_id),
                                      aux.json);
         msg = jsonrpc_create_notify("update", params);
-        jsonrpc_send(aux.monitor->session->rpc, msg);
+        jsonrpc_session_send(aux.monitor->session->js, msg);
     }
 
     return NULL;