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 E80C6C05027 for ; Mon, 20 Feb 2023 13:47:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232310AbjBTNrJ (ORCPT ); Mon, 20 Feb 2023 08:47:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232291AbjBTNrE (ORCPT ); Mon, 20 Feb 2023 08:47:04 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A1C81DB9D for ; Mon, 20 Feb 2023 05:46:43 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 04478B80B96 for ; Mon, 20 Feb 2023 13:46:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E908C433D2; Mon, 20 Feb 2023 13:46:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1676900778; bh=Ef6WGXLOEueMeEB5jwcyiDSDGo1alDNoQ4ftTxD1ZM0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IHiaKEJE1t/2i1X9mNUa7jQB8A5DshufnA5zVaZudZFrBxujeZtEJtRkEfxLNUt4E 32+1fsZSzQNJUTWjIaS9B2OQ64Qw9j8luk+1ceFOUhZ2l1mmZDFu8pA/CivETqCRZv aEmAo59pBCI6ejpXWioDgTet8pt0XZ8Ij82q5JEI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Devid Antonio Filoni , Oleksij Rempel , Marc Kleine-Budde Subject: [PATCH 5.4 064/156] can: j1939: do not wait 250 ms if the same addr was already claimed Date: Mon, 20 Feb 2023 14:35:08 +0100 Message-Id: <20230220133605.018963326@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230220133602.515342638@linuxfoundation.org> References: <20230220133602.515342638@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Devid Antonio Filoni commit 4ae5e1e97c44f4654516c1d41591a462ed62fa7b upstream. The ISO 11783-5 standard, in "4.5.2 - Address claim requirements", states: d) No CF shall begin, or resume, transmission on the network until 250 ms after it has successfully claimed an address except when responding to a request for address-claimed. But "Figure 6" and "Figure 7" in "4.5.4.2 - Address-claim prioritization" show that the CF begins the transmission after 250 ms from the first AC (address-claimed) message even if it sends another AC message during that time window to resolve the address contention with another CF. As stated in "4.4.2.3 - Address-claimed message": In order to successfully claim an address, the CF sending an address claimed message shall not receive a contending claim from another CF for at least 250 ms. As stated in "4.4.3.2 - NAME management (NM) message": 1) A commanding CF can d) request that a CF with a specified NAME transmit the address- claimed message with its current NAME. 2) A target CF shall d) send an address-claimed message in response to a request for a matching NAME Taking the above arguments into account, the 250 ms wait is requested only during network initialization. Do not restart the timer on AC message if both the NAME and the address match and so if the address has already been claimed (timer has expired) or the AC message has been sent to resolve the contention with another CF (timer is still running). Signed-off-by: Devid Antonio Filoni Acked-by: Oleksij Rempel Link: https://lore.kernel.org/all/20221125170418.34575-1-devid.filoni@egluetechnologies.com Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/j1939/address-claim.c | 40 +++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/net/can/j1939/address-claim.c b/net/can/j1939/address-claim.c index f33c47327927..ca4ad6cdd5cb 100644 --- a/net/can/j1939/address-claim.c +++ b/net/can/j1939/address-claim.c @@ -165,6 +165,46 @@ static void j1939_ac_process(struct j1939_priv *priv, struct sk_buff *skb) * leaving this function. */ ecu = j1939_ecu_get_by_name_locked(priv, name); + + if (ecu && ecu->addr == skcb->addr.sa) { + /* The ISO 11783-5 standard, in "4.5.2 - Address claim + * requirements", states: + * d) No CF shall begin, or resume, transmission on the + * network until 250 ms after it has successfully claimed + * an address except when responding to a request for + * address-claimed. + * + * But "Figure 6" and "Figure 7" in "4.5.4.2 - Address-claim + * prioritization" show that the CF begins the transmission + * after 250 ms from the first AC (address-claimed) message + * even if it sends another AC message during that time window + * to resolve the address contention with another CF. + * + * As stated in "4.4.2.3 - Address-claimed message": + * In order to successfully claim an address, the CF sending + * an address claimed message shall not receive a contending + * claim from another CF for at least 250 ms. + * + * As stated in "4.4.3.2 - NAME management (NM) message": + * 1) A commanding CF can + * d) request that a CF with a specified NAME transmit + * the address-claimed message with its current NAME. + * 2) A target CF shall + * d) send an address-claimed message in response to a + * request for a matching NAME + * + * Taking the above arguments into account, the 250 ms wait is + * requested only during network initialization. + * + * Do not restart the timer on AC message if both the NAME and + * the address match and so if the address has already been + * claimed (timer has expired) or the AC message has been sent + * to resolve the contention with another CF (timer is still + * running). + */ + goto out_ecu_put; + } + if (!ecu && j1939_address_is_unicast(skcb->addr.sa)) ecu = j1939_ecu_create_locked(priv, name); -- 2.39.1