rconn: Decentralize and improve disconnection logging.

In some cases the rconn library was logging disconnections twice, and in
other cases it was not logging them at all.  This cleans it up, so that
each disconnection or connection failure should cause one log message.

This commit makes disconnect()'s 'error' argument unused, but it will be
used again in the following commit.

diff --git a/lib/rconn.c b/lib/rconn.c
index 771b3a30400812ccfeb9c23217be0c5332cf86b2..8cac1696e14d82aefcb9ca556b17f2341cf13dc0 100644 (file)
--- a/lib/rconn.c
+++ b/lib/rconn.c
@@ -136,6 +136,7 @@ static void state_transition(struct rconn *, enum state);
 static void set_vconn_name(struct rconn *, const char *name);
 static int try_send(struct rconn *);
 static int reconnect(struct rconn *);
+static void report_error(struct rconn *, int error);
 static void disconnect(struct rconn *, int error);
 static void flush_queue(struct rconn *);
 static void question_connectivity(struct rconn *);
@@ -272,6 +273,7 @@ void
 rconn_reconnect(struct rconn *rc)
 {
     if (rc->state & (S_ACTIVE | S_IDLE)) {
+        VLOG_INFO("%s: disconnecting", rc->name);
         disconnect(rc, 0);
     }
 }
@@ -511,6 +513,7 @@ rconn_recv(struct rconn *rc)
             }
             return buffer;
         } else if (error != EAGAIN) {
+            report_error(rc, error);
             disconnect(rc, error);
         }
     }
@@ -849,6 +852,7 @@ try_send(struct rconn *rc)
     retval = vconn_send(rc->vconn, rc->txq.head);
     if (retval) {
         if (retval != EAGAIN) {
+            report_error(rc, retval);
             disconnect(rc, retval);
         }
         return retval;
@@ -862,26 +866,31 @@ try_send(struct rconn *rc)
     return 0;
 }
 
-/* Disconnects 'rc'.  'error' is used only for logging purposes.  If it is
- * nonzero, then it should be EOF to indicate the connection was closed by the
- * peer in a normal fashion or a positive errno value. */
+/* Reports that 'error' caused 'rc' to disconnect.  'error' may be a positive
+ * errno value, or it may be EOF to indicate that the connection was closed
+ * normally. */
 static void
-disconnect(struct rconn *rc, int error)
+report_error(struct rconn *rc, int error)
+{
+    if (error == EOF) {
+        /* If 'rc' isn't reliable, then we don't really expect this connection
+         * to last forever anyway (probably it's a connection that we received
+         * via accept()), so use DBG level to avoid cluttering the logs. */
+        enum vlog_level level = rc->reliable ? VLL_INFO : VLL_DBG;
+        VLOG(level, "%s: connection closed by peer", rc->name);
+    } else {
+        VLOG_WARN("%s: connection dropped (%s)", rc->name, strerror(error));
+    }
+}
+
+/* Disconnects 'rc'. */
+static void
+disconnect(struct rconn *rc, int error OVS_UNUSED)
 {
     if (rc->reliable) {
         time_t now = time_now();
 
         if (rc->state & (S_CONNECTING | S_ACTIVE | S_IDLE)) {
-            if (error > 0) {
-                VLOG_WARN("%s: connection dropped (%s)",
-                          rc->name, strerror(error));
-            } else if (error == EOF) {
-                if (rc->reliable) {
-                    VLOG_INFO("%s: connection closed by peer", rc->name);
-                }
-            } else {
-                VLOG_INFO("%s: connection dropped", rc->name);
-            }
             vconn_close(rc->vconn);
             rc->vconn = NULL;
             flush_queue(rc);