Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755891AbZJZTVn (ORCPT ); Mon, 26 Oct 2009 15:21:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755479AbZJZTVm (ORCPT ); Mon, 26 Oct 2009 15:21:42 -0400 Received: from alto.filmlight.ltd.uk ([77.107.81.250]:23373 "HELO a.mx.filmlight.ltd.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755450AbZJZTVl (ORCPT ); Mon, 26 Oct 2009 15:21:41 -0400 X-Greylist: delayed 398 seconds by postgrey-1.27 at vger.kernel.org; Mon, 26 Oct 2009 15:21:41 EDT Subject: netlink: symantics for NLM_F_MULTI and NLMSG_DONE ? From: Roger Willcocks To: linux-kernel@vger.kernel.org Content-Type: text/plain Date: Mon, 26 Oct 2009 19:14:53 +0000 Message-Id: <1256584493.10998.784.camel@montana.filmlight.ltd.uk> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-8.el5_2.2) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 985 Lines: 24 The netlink rfc (3549) says that in multi-part messages (messages split over multiple netlink packets), the first and all following headers have the NLM_F_MULTI flag set except for the last header which has the header type NLMSG_DONE. afaict NLMSG_DONE is redundant, since one could simply not set the NLM_F_MULTI flag for the final header; and if a multi-part message can't cross a datagram boundary - which is assumed by e.g. the reading example in http://www.kernel.org/doc/man-pages/online/pages/man7/netlink.7.html - NLMSG_DONE is redundant too. And the rfc doesn't say what NLMSG_DONE /and/ NLM_F_MULTI should mean, although net/netlink/af_netlink.c always sets both. So, what are the symantics for NLM_F_MULTI and NLMSG_DONE? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/