From patchwork Tue Sep 15 07:54:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Linus_L=C3=BCssing?= X-Patchwork-Id: 18181 X-Patchwork-Delegate: sw@simonwunderlich.de Return-Path: X-Original-To: patchwork@open-mesh.org Delivered-To: patchwork@open-mesh.org Received: from diktynna.open-mesh.org (localhost [IPv6:::1]) by diktynna.open-mesh.org (Postfix) with ESMTP id 375AC808BB; Tue, 15 Sep 2020 09:54:26 +0200 (CEST) Received: from mail.aperture-lab.de (mail.aperture-lab.de [IPv6:2a01:4f8:171:314c::100:a1]) by diktynna.open-mesh.org (Postfix) with ESMTPS id CE3C680548 for ; Tue, 15 Sep 2020 09:54:14 +0200 (CEST) From: =?utf-8?q?Linus_L=C3=BCssing?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c0d3.blue; s=2018; t=1600156454; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dkpBFpt1fBAVQz3cAv8UDI6RsllMadM1gxG6GTrmT84=; b=IuKlx7TD+7lYUePruPlL4GKsnHa9iyUW7/ej6uhql0dtyx5HYgHI1un/bAirfpghd74qXX JY/gqNlz5f6H1sWOw0893edOABABC9IhINbSEHmy5zsgNkTHvPndVXHKmfWsoszuzEs0/T sPZwXQOijcl2FDmyk7007DzOKoqeNGewMblaeIEpO7/8MFgnlf6MQOuRaNBm6yThtnXVS9 ll/h3XvraSiUll1SxwAeDv83jvtN+RqN0+9LvFT3tvdrkDoNy3T/T1TY6uHSjEKkjIQ2BG R2PMVu2clqAgVgsdJSHVh4U7OIb0tktwfuzRtqSRYrk5xERoErp60Kn7c9PZJw== To: b.a.t.m.a.n@lists.open-mesh.org Cc: =?utf-8?q?Linus_L=C3=BCssing?= Subject: [PATCH maint v6 3/3] batman-adv: mcast: fix duplicate mcast packets from BLA backbone to mesh Date: Tue, 15 Sep 2020 09:54:10 +0200 Message-Id: <20200915075410.13932-4-linus.luessing@c0d3.blue> In-Reply-To: <20200915075410.13932-1-linus.luessing@c0d3.blue> References: <20200915075410.13932-1-linus.luessing@c0d3.blue> MIME-Version: 1.0 Authentication-Results: ORIGINATING; auth=pass smtp.auth=linus.luessing@c0d3.blue smtp.mailfrom=linus.luessing@c0d3.blue ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=open-mesh.org; s=20121; t=1600156454; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=dkpBFpt1fBAVQz3cAv8UDI6RsllMadM1gxG6GTrmT84=; b=RDcBon+oETlAy6PO8Eyg1p6UvMz7d4596mCca4T7s/6P3sjfY2zZv2sidx84dkrzxPB6kE kgFsJcf8eNZSXjyX6JVK8F5aXdTAaCE/uYHVwQ9DC53OjOd9UdOmWQJqM+h6IMb7KR2shi C8gRiYXnMiRjhv9R8JsPvilSdi4wJAU= ARC-Seal: i=1; s=20121; d=open-mesh.org; t=1600156454; a=rsa-sha256; cv=none; b=PhsM4qGs4nSdU3I3nJD3K80uVxLj5/tq8Ah5qqmjOZuaZwhgo6FouEXSythWeHWAFcrnSv XVBUtRFFKj8f6ulxdo3G6DrQEYpdz2plFtTD5LFYK9PnIvZ9BImZ4iwvTUuCuevnVQfADB Y6JOjeLH7MK0LbCuSNswvsnoU9oZ0ek= ARC-Authentication-Results: i=1; diktynna.open-mesh.org; dkim=none (invalid DKIM record) header.d=c0d3.blue header.s=2018 header.b=IuKlx7TD; spf=none (diktynna.open-mesh.org: domain of linus.luessing@c0d3.blue has no SPF policy when checking 2a01:4f8:171:314c::100:a1) smtp.mailfrom=linus.luessing@c0d3.blue Message-ID-Hash: DKOINE3UBXKHNREFUSL77OL6PWRJH3G3 X-Message-ID-Hash: DKOINE3UBXKHNREFUSL77OL6PWRJH3G3 X-MailFrom: linus.luessing@c0d3.blue X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-b.a.t.m.a.n.lists.open-mesh.org-0; header-match-b.a.t.m.a.n.lists.open-mesh.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; suspicious-header X-Mailman-Version: 3.2.1 Precedence: list Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Scenario: * Multicast frame send from BLA backbone gateways (multiple nodes with their bat0 bridged together, with BLA enabled) sharing the same LAN to nodes in the mesh Issue: * Nodes receive the frame multiple times on bat0 from the mesh, once from each foreign BLA backbone gateway which shares the same LAN with another For multicast frames via batman-adv broadcast packets coming from the same BLA backbone but from different backbone gateways duplicates are currently detected via a CRC history of previously received packets. However this CRC so far was not performed for multicast frames received via batman-adv unicast packets. Fixing this by appyling the same check for such packets, too. Room for improvements in the future: Ideally we would introduce the possibility to not only claim a client, but a complete originator, too. This would allow us to only send a multicast-in-unicast packet from a BLA backbone gateway claiming the node and by that avoid potential redundant transmissions in the first place. Fixes: e5cf86d30a9b ("batman-adv: add broadcast duplicate check") Signed-off-by: Linus Lüssing --- net/batman-adv/bridge_loop_avoidance.c | 103 +++++++++++++++++++++---- 1 file changed, 87 insertions(+), 16 deletions(-) diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index 3d2a66f2..07f3ca8b 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -1580,13 +1580,16 @@ int batadv_bla_init(struct batadv_priv *bat_priv) } /** - * batadv_bla_check_bcast_duplist() - Check if a frame is in the broadcast dup. + * batadv_bla_check_duplist() - Check if a frame is in the broadcast dup. * @bat_priv: the bat priv with all the soft interface information - * @skb: contains the bcast_packet to be checked + * @skb: contains the multicast packet to be checked + * @payload_ptr: pointer to position inside the head buffer of the skb + * marking the start of the data to be CRC'ed + * @orig: originator mac address, NULL if unknown * - * check if it is on our broadcast list. Another gateway might - * have sent the same packet because it is connected to the same backbone, - * so we have to remove this duplicate. + * Check if it is on our broadcast list. Another gateway might have sent the + * same packet because it is connected to the same backbone, so we have to + * remove this duplicate. * * This is performed by checking the CRC, which will tell us * with a good chance that it is the same packet. If it is furthermore @@ -1595,19 +1598,17 @@ int batadv_bla_init(struct batadv_priv *bat_priv) * * Return: true if a packet is in the duplicate list, false otherwise. */ -bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv, - struct sk_buff *skb) +static bool batadv_bla_check_duplist(struct batadv_priv *bat_priv, + struct sk_buff *skb, u8 *payload_ptr, + const u8 *orig) { + struct batadv_bcast_duplist_entry *entry; + bool ret = false; int i, curr; __be32 crc; - struct batadv_bcast_packet *bcast_packet; - struct batadv_bcast_duplist_entry *entry; - bool ret = false; - - bcast_packet = (struct batadv_bcast_packet *)skb->data; /* calculate the crc ... */ - crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1)); + crc = batadv_skb_crc32(skb, payload_ptr); spin_lock_bh(&bat_priv->bla.bcast_duplist_lock); @@ -1626,8 +1627,21 @@ bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv, if (entry->crc != crc) continue; - if (batadv_compare_eth(entry->orig, bcast_packet->orig)) - continue; + /* are the originators both known and not anonymous? */ + if (orig && !is_zero_ether_addr(orig) && + !is_zero_ether_addr(entry->orig)) { + /* If known, check if the new frame came from + * the same originator: + * We are safe to take identical frames from the + * same orig, if known, as multiplications in + * the mesh are detected via the (orig, seqno) pair. + * So we can be a bit more liberal here and allow + * identical frames from the same orig which the source + * host might have sent multiple times on purpose. + */ + if (batadv_compare_eth(entry->orig, orig)) + continue; + } /* this entry seems to match: same crc, not too old, * and from another gw. therefore return true to forbid it. @@ -1643,7 +1657,14 @@ bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv, entry = &bat_priv->bla.bcast_duplist[curr]; entry->crc = crc; entry->entrytime = jiffies; - ether_addr_copy(entry->orig, bcast_packet->orig); + + /* known originator */ + if (orig) + ether_addr_copy(entry->orig, orig); + /* anonymous originator */ + else + eth_zero_addr(entry->orig); + bat_priv->bla.bcast_duplist_curr = curr; out: @@ -1652,6 +1673,48 @@ bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv, return ret; } +/** + * batadv_bla_check_ucast_duplist() - Check if a frame is in the broadcast dup. + * @bat_priv: the bat priv with all the soft interface information + * @skb: contains the multicast packet to be checked, decapsulated from a + * unicast_packet + * + * Check if it is on our broadcast list. Another gateway might have sent the + * same packet because it is connected to the same backbone, so we have to + * remove this duplicate. + * + * Return: true if a packet is in the duplicate list, false otherwise. + */ +static bool batadv_bla_check_ucast_duplist(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + return batadv_bla_check_duplist(bat_priv, skb, (u8 *)skb->data, NULL); +} + +/** + * batadv_bla_check_bcast_duplist() - Check if a frame is in the broadcast dup. + * @bat_priv: the bat priv with all the soft interface information + * @skb: contains the bcast_packet to be checked + * + * Check if it is on our broadcast list. Another gateway might have sent the + * same packet because it is connected to the same backbone, so we have to + * remove this duplicate. + * + * Return: true if a packet is in the duplicate list, false otherwise. + */ +bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv, + struct sk_buff *skb) +{ + struct batadv_bcast_packet *bcast_packet; + u8 *payload_ptr; + + bcast_packet = (struct batadv_bcast_packet *)skb->data; + payload_ptr = (u8 *)(bcast_packet + 1); + + return batadv_bla_check_duplist(bat_priv, skb, payload_ptr, + bcast_packet->orig); +} + /** * batadv_bla_is_backbone_gw_orig() - Check if the originator is a gateway for * the VLAN identified by vid. @@ -1866,6 +1929,14 @@ bool batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, packet_type == BATADV_UNICAST) goto handled; + /* potential duplicates from foreign BLA backbone gateways via + * multicast-in-unicast packets + */ + if (is_multicast_ether_addr(ethhdr->h_dest) && + packet_type == BATADV_UNICAST && + batadv_bla_check_ucast_duplist(bat_priv, skb)) + goto handled; + ether_addr_copy(search_claim.addr, ethhdr->h_source); search_claim.vid = vid; claim = batadv_claim_hash_find(bat_priv, &search_claim);