From patchwork Tue Mar 17 23:27:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 229171 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, UNWANTED_LANGUAGE_BODY, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9351BC5ACD6 for ; Tue, 17 Mar 2020 23:28:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68FC420674 for ; Tue, 17 Mar 2020 23:28:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=narfation.org header.i=@narfation.org header.b="wWxefmqP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727121AbgCQX2D (ORCPT ); Tue, 17 Mar 2020 19:28:03 -0400 Received: from dvalin.narfation.org ([213.160.73.56]:53636 "EHLO dvalin.narfation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727071AbgCQX2C (ORCPT ); Tue, 17 Mar 2020 19:28:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1584487680; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9HIpCSeN6V4nS9kXIL69UcHzqYtZPSTxPbAYslk2oVU=; b=wWxefmqPN4RZWQSEPdmDKsti/xScMKDbSvlEChnl3DM2t0dwV6EB2Fov1AuLGADE6dHDZR rGN1OnqHSy9sEsxPxNFrhlCXftgtnJXCa9UQJstArv3fc2asqMOi1HLYEgKsdNCfr34eAb 0Au8tW9zBLOBc+1ILSICTA0ZqzNZQL8= From: Sven Eckelmann To: stable@vger.kernel.org Cc: Simon Wunderlich , Alfons Name , Marek Lindner , Antonio Quartulli Subject: [PATCH 4.4 19/48] batman-adv: lock crc access in bridge loop avoidance Date: Wed, 18 Mar 2020 00:27:05 +0100 Message-Id: <20200317232734.6127-20-sven@narfation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200317232734.6127-1-sven@narfation.org> References: <20200317232734.6127-1-sven@narfation.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Simon Wunderlich commit 5a1dd8a4773d4c24e925cc6154826d555a85c370 upstream. We have found some networks in which nodes were constantly requesting other nodes BLA claim tables to synchronize, just to ask for that again once completed. The reason was that the crc checksum of the asked nodes were out of sync due to missing locking and multiple writes to the same crc checksum when adding/removing entries. Therefore the asked nodes constantly reported the wrong crc, which caused repeating requests. To avoid multiple functions changing a backbone gateways crc entry at the same time, lock it using a spinlock. Signed-off-by: Simon Wunderlich Tested-by: Alfons Name Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli --- net/batman-adv/bridge_loop_avoidance.c | 35 ++++++++++++++++++++++---- net/batman-adv/types.h | 2 ++ 2 files changed, 32 insertions(+), 5 deletions(-) diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index 6749fe7e0321..f7b30d8ec63b 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -256,7 +256,9 @@ batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw) } /* all claims gone, initialize CRC */ + spin_lock_bh(&backbone_gw->crc_lock); backbone_gw->crc = BATADV_BLA_CRC_INIT; + spin_unlock_bh(&backbone_gw->crc_lock); } /** @@ -407,6 +409,7 @@ batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, u8 *orig, entry->lasttime = jiffies; entry->crc = BATADV_BLA_CRC_INIT; entry->bat_priv = bat_priv; + spin_lock_init(&entry->crc_lock); atomic_set(&entry->request_sent, 0); atomic_set(&entry->wait_periods, 0); ether_addr_copy(entry->orig, orig); @@ -556,7 +559,9 @@ static void batadv_bla_send_announce(struct batadv_priv *bat_priv, __be16 crc; memcpy(mac, batadv_announce_mac, 4); + spin_lock_bh(&backbone_gw->crc_lock); crc = htons(backbone_gw->crc); + spin_unlock_bh(&backbone_gw->crc_lock); memcpy(&mac[4], &crc, 2); batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid, @@ -617,14 +622,18 @@ static void batadv_bla_add_claim(struct batadv_priv *bat_priv, "bla_add_claim(): changing ownership for %pM, vid %d\n", mac, BATADV_PRINT_VID(vid)); + spin_lock_bh(&claim->backbone_gw->crc_lock); claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); + spin_unlock_bh(&claim->backbone_gw->crc_lock); batadv_backbone_gw_free_ref(claim->backbone_gw); } /* set (new) backbone gw */ atomic_inc(&backbone_gw->refcount); claim->backbone_gw = backbone_gw; + spin_lock_bh(&backbone_gw->crc_lock); backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); + spin_unlock_bh(&backbone_gw->crc_lock); backbone_gw->lasttime = jiffies; claim_free_ref: @@ -652,7 +661,9 @@ static void batadv_bla_del_claim(struct batadv_priv *bat_priv, batadv_choose_claim, claim); batadv_claim_free_ref(claim); /* reference from the hash is gone */ + spin_lock_bh(&claim->backbone_gw->crc_lock); claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); + spin_unlock_bh(&claim->backbone_gw->crc_lock); /* don't need the reference from hash_find() anymore */ batadv_claim_free_ref(claim); @@ -663,7 +674,7 @@ static int batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr, u8 *backbone_addr, unsigned short vid) { struct batadv_bla_backbone_gw *backbone_gw; - u16 crc; + u16 backbone_crc, crc; if (memcmp(an_addr, batadv_announce_mac, 4) != 0) return 0; @@ -682,12 +693,16 @@ static int batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr, "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n", BATADV_PRINT_VID(vid), backbone_gw->orig, crc); - if (backbone_gw->crc != crc) { + spin_lock_bh(&backbone_gw->crc_lock); + backbone_crc = backbone_gw->crc; + spin_unlock_bh(&backbone_gw->crc_lock); + + if (backbone_crc != crc) { batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv, "handle_announce(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n", backbone_gw->orig, BATADV_PRINT_VID(backbone_gw->vid), - backbone_gw->crc, crc); + backbone_crc, crc); batadv_bla_send_request(backbone_gw); } else { @@ -1658,6 +1673,7 @@ int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset) struct batadv_bla_claim *claim; struct batadv_hard_iface *primary_if; struct hlist_head *head; + u16 backbone_crc; u32 i; bool is_own; u8 *primary_addr; @@ -1680,11 +1696,15 @@ int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset) hlist_for_each_entry_rcu(claim, head, hash_entry) { is_own = batadv_compare_eth(claim->backbone_gw->orig, primary_addr); + + spin_lock_bh(&claim->backbone_gw->crc_lock); + backbone_crc = claim->backbone_gw->crc; + spin_unlock_bh(&claim->backbone_gw->crc_lock); seq_printf(seq, " * %pM on %5d by %pM [%c] (%#.4x)\n", claim->addr, BATADV_PRINT_VID(claim->vid), claim->backbone_gw->orig, (is_own ? 'x' : ' '), - claim->backbone_gw->crc); + backbone_crc); } rcu_read_unlock(); } @@ -1703,6 +1723,7 @@ int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset) struct batadv_hard_iface *primary_if; struct hlist_head *head; int secs, msecs; + u16 backbone_crc; u32 i; bool is_own; u8 *primary_addr; @@ -1733,10 +1754,14 @@ int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset) if (is_own) continue; + spin_lock_bh(&backbone_gw->crc_lock); + backbone_crc = backbone_gw->crc; + spin_unlock_bh(&backbone_gw->crc_lock); + seq_printf(seq, " * %pM on %5d %4i.%03is (%#.4x)\n", backbone_gw->orig, BATADV_PRINT_VID(backbone_gw->vid), secs, - msecs, backbone_gw->crc); + msecs, backbone_crc); } rcu_read_unlock(); } diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 3188907c2b4b..4764495b4071 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -884,6 +884,7 @@ struct batadv_socket_packet { * backbone gateway - no bcast traffic is formwared until the situation was * resolved * @crc: crc16 checksum over all claims + * @crc_lock: lock protecting crc * @refcount: number of contexts the object is used * @rcu: struct used for freeing in an RCU-safe manner */ @@ -897,6 +898,7 @@ struct batadv_bla_backbone_gw { atomic_t wait_periods; atomic_t request_sent; u16 crc; + spinlock_t crc_lock; /* protects crc */ atomic_t refcount; struct rcu_head rcu; };