add support for conn manager

core/network/conn.go

@@ -35,6 +35,18 @@ func (c *ConnError) Unwrap() error {
 	return c.TransportError
 }
 
+const (
+	ConnNoError                   ConnErrorCode = 0
+	ConnProtocolNegotiationFailed ConnErrorCode = 1001
+	ConnResourceLimitExceeded     ConnErrorCode = 1002
+	ConnRateLimited               ConnErrorCode = 1003
+	ConnProtocolViolation         ConnErrorCode = 1004
+	ConnSupplanted                ConnErrorCode = 1005
+	ConnGarbageCollected          ConnErrorCode = 1006
+	ConnShutdown                  ConnErrorCode = 1007
+	ConnGated                     ConnErrorCode = 1008
+)
+
 // Conn is a connection to a remote peer. It multiplexes streams.
 // Usually there is no need to use a Conn directly, but it may
 // be useful to get information about the peer on the other side:

p2p/net/connmgr/connmgr.go

@@ -175,7 +175,8 @@ func (cm *BasicConnMgr) memoryEmergency() {
 	// Trim connections without paying attention to the silence period.
 	for _, c := range cm.getConnsToCloseEmergency(target) {
 		log.Infow("low on memory. closing conn", "peer", c.RemotePeer())
-		c.Close()
+
+		c.CloseWithError(network.ConnGarbageCollected)
 	}
 
 	// finally, update the last trim time.
@@ -388,7 +389,7 @@ func (cm *BasicConnMgr) trim() {
 	// do the actual trim.
 	for _, c := range cm.getConnsToClose() {
 		log.Debugw("closing conn", "peer", c.RemotePeer())
-		c.Close()
+		c.CloseWithError(network.ConnGarbageCollected)
 	}
 }
 

p2p/net/connmgr/connmgr_test.go

@@ -33,6 +33,14 @@ func (c *tconn) Close() error {
 	return nil
 }
 
+func (c *tconn) CloseWithError(code network.ConnErrorCode) error {
+	atomic.StoreUint32(&c.closed, 1)
+	if c.disconnectNotify != nil {
+		c.disconnectNotify(nil, c)
+	}
+	return nil
+}
+
 func (c *tconn) isClosed() bool {
 	return atomic.LoadUint32(&c.closed) == 1
 }