From patchwork Thu Feb 25 06:29:54 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andreas Pape X-Patchwork-Id: 15841 X-Patchwork-Delegate: mareklindner@neomailbox.ch Return-Path: X-Original-To: patchwork@open-mesh.org Delivered-To: patchwork@open-mesh.org Received: from open-mesh.org (localhost [127.0.0.1]) by open-mesh.org (Postfix) with ESMTP id A423481718; Thu, 25 Feb 2016 07:30:00 +0100 (CET) Received-SPF: None (no SPF record) identity=mailfrom; client-ip=62.157.123.121; helo=mail2.phoenixcontact.com; envelope-from=apape@phoenixcontact.com; receiver=b.a.t.m.a.n@lists.open-mesh.org Authentication-Results: open-mesh.org; dmarc=none header.from=phoenixcontact.com Received: from mail2.phoenixcontact.com (mail2.phoenixcontact.com [62.157.123.121]) by open-mesh.org (Postfix) with ESMTPS id ACCC28161F for ; Thu, 25 Feb 2016 07:29:58 +0100 (CET) Received: from localhost.localdomain ([149.208.237.66]) by de-nice01.de.phoenixcontact.com with ESMTP id 2016022507295652-8424 ; Thu, 25 Feb 2016 07:29:56 +0100 From: Andreas Pape To: b.a.t.m.a.n@lists.open-mesh.org X-Mailer: git-send-email 1.7.0.4 X-MIMETrack: Itemize by SMTP Server on DE-NICE01/Hub/SRV/DE/Phoenix Contact at 25.02.2016 07:29:56, Serialize by ntm_grab.EXE on nemex02/spoke/SRV/DE/Phoenix Contact at 25.02.2016 07:29:52, Serialize complete at 25.02.2016 07:29:52, Itemize by ntm_grab.EXE on nemex02/spoke/SRV/DE/Phoenix Contact at 25.02.2016 07:29:52, Serialize by Router on nemex02/spoke/SRV/DE/Phoenix Contact at 25.02.2016 07:29:52 X-TNEFEvaluated: 1 Message-ID: <1456381794-29716-1-git-send-email-apape@phoenixcontact.com> Date: Thu, 25 Feb 2016 07:29:54 +0100 content-transfer-encoding: quoted-printable content-type: text/plain; charset="utf-8" Subject: [B.A.T.M.A.N.] [PATCH 3/7] batman-adv: prevent duplication of ARP replies when DAT is used X-BeenThere: b.a.t.m.a.n@lists.open-mesh.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking Errors-To: b.a.t.m.a.n-bounces@lists.open-mesh.org Sender: "B.A.T.M.A.N" This patch covers the case of a bla setup with enabled dat if none of the common gateways of the same backbone has already knowledge of the searched ip address and therefore has to ask via dat some of the other mesh nodes. A broadcast arp request is coming from the backbone and each backbone gateway starts an address resolution via other dat mesh nodes. In this case it should be prevented that multiple answers from dat enabled mesh nodes reach the backbone gateways leading to multiple replies in a common backbone again. Signed-off-by: Andreas Pape --- net/batman-adv/distributed-arp-table.c | 63 +++++++++++++++++++++++++++++++- 1 files changed, 62 insertions(+), 1 deletions(-) -- 1.7.0.4 .................................................................. PHOENIX CONTACT ELECTRONICS GmbH Sitz der Gesellschaft / registered office of the company: 31812 Bad Pyrmont USt-Id-Nr.: DE811742156 Amtsgericht Hannover HRB 100528 / district court Hannover HRB 100528 Geschäftsführer / Executive Board: Roland Bent, Dr. Martin Heubeck diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c index fe46a3d..53149e2 100644 --- a/net/batman-adv/distributed-arp-table.c +++ b/net/batman-adv/distributed-arp-table.c @@ -1081,6 +1081,8 @@ bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv, u8 *hw_src; struct sk_buff *skb_new; struct batadv_dat_entry *dat_entry = NULL; + struct batadv_unicast_4addr_packet *unicast_4addr_packet; + struct batadv_orig_node *orig_node = NULL; bool ret = false; unsigned short vid; int err; @@ -1104,8 +1106,35 @@ bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv, batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst, vid); - if (!dat_entry) + if (!dat_entry) { + /* Check if this is a 4addr unicast DAT_DHT_GET frame from + * another backbone gw of the same backbone. If yes, drop + * it as this leads to multiplication of arp requests in bla + * setups as long as there is no dat_entry fo this answer. + * In this case better drop the DHT_GET. Normal bla code + * doesn't take care of these packets as they are tunneled + * via unicast. + */ + unicast_4addr_packet = + (struct batadv_unicast_4addr_packet *)skb->data; + orig_node = + batadv_orig_hash_find(bat_priv, unicast_4addr_packet->src); + if (orig_node) { + if ((unicast_4addr_packet->u.packet_type == BATADV_UNICAST_4ADDR) && + (unicast_4addr_packet->subtype == BATADV_P_DAT_DHT_GET) && + (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))) { + batadv_dbg(BATADV_DBG_DAT, bat_priv, "Doubled ARP request removed: " + "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]; originator: %pM\n", + hw_src, &ip_src, + batadv_arp_hw_dst(skb, hdr_size), &ip_dst, + unicast_4addr_packet->src); + ret = true; + } + batadv_orig_node_put(orig_node); + } + goto out; + } skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, bat_priv->soft_iface, ip_dst, hw_src, @@ -1204,6 +1233,7 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, __be32 ip_src, ip_dst; u8 *hw_src, *hw_dst; bool dropped = false; + struct batadv_dat_entry *dat_entry = NULL; unsigned short vid; if (!atomic_read(&bat_priv->distributed_arp_table)) @@ -1223,12 +1253,41 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, hw_dst = batadv_arp_hw_dst(skb, hdr_size); ip_dst = batadv_arp_ip_dst(skb, hdr_size); + /* If ip_dst is already in cache and has the right mac address, + * drop this frame if this ARP reply is destined for us. We have + * most probably received already a reply from someone else. Delivering + * this frame would lead to doubled receive of an ARP reply. + */ + dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_src, vid); + if ((dat_entry) && (batadv_compare_eth(hw_src, dat_entry->mac_addr))) { + batadv_dbg(BATADV_DBG_DAT, bat_priv, "Doubled ARP reply removed: " + "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]; dat_entry: %pM-%pI4\n", + hw_src, &ip_src, hw_dst, &ip_dst, dat_entry->mac_addr, + &dat_entry->ip); + dropped = true; + goto out; + } + /* Update our internal cache with both the IP addresses the node got * within the ARP reply */ batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid); batadv_dat_entry_add(bat_priv, ip_dst, hw_dst, vid); + /* If BLA is enabled, only forward ARP replies if we have claimed the + * source of the ARP reply or if no one else of the same backbone has + * already claimed that client. This prevents that different gateways + * to the same backbone all forward the ARP reply leading to multiple + * replies in the backbone. + */ + if (!batadv_bla_handle_local_claim(bat_priv, hw_src, vid)) { + batadv_dbg(BATADV_DBG_DAT, bat_priv, + "Device %pM claimed by another backbone gw. Drop ARP reply.\n", + hw_src); + dropped = true; + goto out; + } + /* if this REPLY is directed to a client of mine, let's deliver the * packet to the interface */ @@ -1241,6 +1300,8 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, out: if (dropped) kfree_skb(skb); + if (dat_entry) + batadv_dat_entry_put(dat_entry); /* if dropped == false -> deliver to the interface */ return dropped; }