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List:       openvswitch-dev
Subject:    [ovs-dev] [PATCH 3/4] rconn: Preserve the name of an unreliable connection beyond disconnection.
From:       blp () nicira ! com (Ben Pfaff)
Date:       2014-04-30 17:51:24
Message-ID: 1398880285-19758-3-git-send-email-blp () nicira ! com
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An rconn has a human-readable name that typically designates both endpoints
of the connection.  For a "reliable" rconn, that automatically reconnects,
the name remains constant regardless of whether the rconn is currently
connected.  Until now, though, an "unreliable" rconn, that cannot
automatically reconnect, kept its name only until disconnection occurred.
This is OK for the uses currently in the OVS tree, which only use the name
of a rconn while it is connected, but an upcoming commit will add a final
log message following disconnection in some cases, and it makes the log
messages less useful if unreliable rconns just report "void" in that case.
This commit, therefore, modifies the rconn code so that unreliable rconns
preserve their names past disconnection, just like reliable ones.

Signed-off-by: Ben Pfaff <blp at nicira.com>
---
 lib/rconn.c |   45 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/lib/rconn.c b/lib/rconn.c
index f19c14e..fae1db9 100644
--- a/lib/rconn.c
+++ b/lib/rconn.c
@@ -39,12 +39,31 @@ COVERAGE_DEFINE(rconn_overflow);
 COVERAGE_DEFINE(rconn_queued);
 COVERAGE_DEFINE(rconn_sent);
 
+/* The connection states have the following meanings:
+ *
+ *    - S_VOID: No connection information is configured.
+ *
+ *    - S_BACKOFF: Waiting for a period of time before reconnecting.
+ *
+ *    - S_CONNECTING: A connection attempt is in progress and has not yet
+ *      succeeded or failed.
+ *
+ *    - S_ACTIVE: A connection has been established and appears to be healthy.
+ *
+ *    - S_IDLE: A connection has been established but has been idle for some
+ *      time.  An echo request has been sent, but no reply has yet been
+ *      received.
+ *
+ *    - S_DISCONNECTED: An unreliable connection has disconnected and cannot be
+ *      automatically retried.
+ */
 #define STATES                                  \
     STATE(VOID, 1 << 0)                         \
     STATE(BACKOFF, 1 << 1)                      \
     STATE(CONNECTING, 1 << 2)                   \
     STATE(ACTIVE, 1 << 3)                       \
-    STATE(IDLE, 1 << 4)
+    STATE(IDLE, 1 << 4)                         \
+    STATE(DISCONNECTED, 1 << 5)
 enum state {
 #define STATE(NAME, VALUE) S_##NAME = VALUE,
     STATES
@@ -580,6 +599,20 @@ run_IDLE(struct rconn *rc)
     }
 }
 
+static unsigned int
+timeout_DISCONNECTED(const struct rconn *rc OVS_UNUSED)
+    OVS_REQUIRES(rc->mutex)
+{
+    return UINT_MAX;
+}
+
+static void
+run_DISCONNECTED(struct rconn *rc OVS_UNUSED)
+    OVS_REQUIRES(rc->mutex)
+{
+    /* Nothing to do. */
+}
+
 /* Performs whatever activities are necessary to maintain 'rc': if 'rc' is
  * disconnected, attempts to (re)connect, backing off as necessary; if 'rc' is
  * connected, attempts to send packets in the send queue, if any. */
@@ -858,7 +891,7 @@ rconn_get_target(const struct rconn *rc)
 bool
 rconn_is_alive(const struct rconn *rconn)
 {
-    return rconn->state != S_VOID;
+    return rconn->state != S_VOID && rconn->state != S_DISCONNECTED;
 }
 
 /* Returns true if 'rconn' is connected, false otherwise. */
@@ -1165,13 +1198,15 @@ disconnect(struct rconn *rc, int error)
     OVS_REQUIRES(rc->mutex)
 {
     rc->last_error = error;
+    if (rc->vconn) {
+        vconn_close(rc->vconn);
+        rc->vconn = NULL;
+    }
     if (rc->reliable) {
         time_t now = time_now();
 
         if (rc->state & (S_CONNECTING | S_ACTIVE | S_IDLE)) {
             rc->last_disconnected = now;
-            vconn_close(rc->vconn);
-            rc->vconn = NULL;
             flush_queue(rc);
         }
 
@@ -1193,7 +1228,7 @@ disconnect(struct rconn *rc, int error)
         state_transition(rc, S_BACKOFF);
     } else {
         rc->last_disconnected = time_now();
-        rconn_disconnect__(rc);
+        state_transition(rc, S_DISCONNECTED);
     }
 }
 
-- 
1.7.10.4


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