[XrdCl/XrdTls] Retry if SSL_read/write yield SSL_ERROR_NONE.

src/XrdCl/XrdClTls.cc

@@ -129,6 +129,12 @@ namespace XrdCl
     }
     pTlsHSRevert = None;
 
+    //------------------------------------------------------------------------
+    // If we didn't manage to read any data wait for another read event
+    //------------------------------------------------------------------------
+    if( bytesRead == 0 )
+      return Status( stOK, suRetry );
+
     return status;
   }
 
@@ -185,6 +191,15 @@ namespace XrdCl
     }
     pTlsHSRevert = None;
 
+    //------------------------------------------------------------------------
+    // If we didn't manage to read any data wait for another write event
+    //
+    // Adding this by symmetry, never actually experienced this (for reads
+    // it has been experienced)
+    //------------------------------------------------------------------------
+    if( bytesWritten == 0 )
+      return Status( stOK, suRetry );
+
     return status;
   }
 

src/XrdTls/XrdTlsSocket.cc

@@ -467,6 +467,7 @@ XrdTls::RC XrdTlsSocket::Read( char *buffer, size_t size, int &bytesRead )
     // not the handshake actually is finished (semi-accurate)
     //
     error = Diagnose(SSL_get_error( pImpl->ssl, rc ));
+    if( error == XrdTls::RC::TLS_AOK ) bytesRead = 0;
     pImpl->hsDone = bool( SSL_is_init_finished( pImpl->ssl ) );
 
     // The connection creator may wish that we wait for the handshake to
@@ -565,6 +566,7 @@ XrdTls::RC XrdTlsSocket::Write( const char *buffer, size_t size,
     // not the handshake actually is finished (semi-accurate)
     //
     pImpl->hsDone = bool( SSL_is_init_finished( pImpl->ssl ) );
+    if( error == XrdTls::RC::TLS_AOK ) bytesWritten = 0;
     error = Diagnose(SSL_get_error( pImpl->ssl, rc ));
 
     // The connection creator may wish that we wait for the handshake to