From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD24BC77B72 for ; Thu, 20 Apr 2023 08:55:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234313AbjDTIzP (ORCPT ); Thu, 20 Apr 2023 04:55:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234199AbjDTIx5 (ORCPT ); Thu, 20 Apr 2023 04:53:57 -0400 Received: from mta-64-227.siemens.flowmailer.net (mta-64-227.siemens.flowmailer.net [185.136.64.227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 568E846BB for ; Thu, 20 Apr 2023 01:52:06 -0700 (PDT) Received: by mta-64-227.siemens.flowmailer.net with ESMTPSA id 202304200852011396a59810ab83a424 for ; Thu, 20 Apr 2023 10:52:01 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=fm1; d=siemens.com; i=daniel.starke@siemens.com; h=Date:From:Subject:To:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:Cc:References:In-Reply-To; bh=3x2yGjeK5u1omGmfHkW7ePEBZf1+enMbPDW41ey/pcA=; b=jC6VnpGptfOYjt/kcGttoWZ0iYVUQEywQ1BjuMJ7ovnlexEs3HPeifOq1ZgRqGafxcj8qQ jvlLATkBil/ZBinzu123fmdn65aKhGVKJ4W9IhUFH94BNEuBOIdUGJcTrOo/7WghXGT6vWi2 IWDn2WVzvkkdHrkZZQAu4MDiJzsMY=; From: "D. Starke" To: linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, ilpo.jarvinen@linux.intel.com Cc: linux-kernel@vger.kernel.org, Daniel Starke Subject: [PATCH v2 7/9] tty: n_gsm: increase gsm_mux unsupported counted where appropriate Date: Thu, 20 Apr 2023 10:50:15 +0200 Message-Id: <20230420085017.7314-7-daniel.starke@siemens.com> In-Reply-To: <20230420085017.7314-1-daniel.starke@siemens.com> References: <20230420085017.7314-1-daniel.starke@siemens.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Flowmailer-Platform: Siemens Feedback-ID: 519:519-314044:519-21489:flowmailer Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Daniel Starke The structure gsm_mux contains the 'unsupported' field. However, there is currently no place in the code which increases this counter. Increase the 'unsupported' statistics counter in the following case: - an unsupported frame type has been requested by the peer via parameter negotiation - a control frame with an unsupported but known command has been received Note that we have no means to detect an inconsistent/unsupported adaptation sufficient accuracy as this changes the structure of the UI/UIH frames. E.g. a one byte header is added in case of convergence layer type 2 instead of 1 and contains the modem signal octet with the state of the signal lines. There is no checksum or other value which indicates of this field is correct or should be present. Therefore, we can only assume protocol correctness here. See also 'gsm_dlci_data()' where this is handled. Signed-off-by: Daniel Starke --- drivers/tty/n_gsm.c | 3 +++ 1 file changed, 3 insertions(+) v1 -> v2: Added details about missing detection of inconsistent/unsupported adaption to the commit message. A question about this came up during the review. Link: https://lore.kernel.org/all/AS4PR10MB58955AB89CC251446B7509CBE0919@AS4PR10MB5895.EURPRD10.PROD.OUTLOOK.COM/ diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index cc7be05c37ce..ce06cbbe79af 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1589,6 +1589,7 @@ static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr, if (debug & DBG_ERRORS) pr_info("%s unsupported I frame request in PN\n", __func__); + gsm->unsupported++; return -EINVAL; default: if (debug & DBG_ERRORS) @@ -1896,6 +1897,8 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, /* Optional unsupported commands */ case CMD_RPN: /* Remote port negotiation */ case CMD_SNC: /* Service negotiation command */ + gsm->unsupported++; + fallthrough; default: /* Reply to bad commands with an NSC */ buf[0] = command; -- 2.34.1