From patchwork Mon Sep 14 01:21:34 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: 18167 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 59E4F80821; Mon, 14 Sep 2020 03:21:43 +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 8C1B680799 for ; Mon, 14 Sep 2020 03:21:39 +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=1600046499; 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=SNnR/kQrMM/sLFu8uuD817v7EOHUbl4ZbaR+1+GWa40=; b=Xe3ajBE21MBjnJRngRiPjeu36ELhTR6ZUYR65xsN+jhYwADGYsLjBzM7bMXCziG9DDZuHl tdrV8ILWE0K0LGUz24i1L7xKEIUm6KxnS4sPbtZhFXs+ICX+z0T6oCrTGhTIG1gApwWGvo aR0vFkvqnaSUke3O31zRbE/BPZzRy7ufnRSGLEqpEmbHsQL6wcupVJqnqkfHJBe/mKtObL 2TFjBewI1LhAheNJpWsQYuOOiBwi5pRcv4Ao3VxY/0m3eJGc8P9OM37kcrWBRcdPjUBpwG FqXilv00N/aJ//1/Wn0Qx2yyOPFELrwxhKx5RazsxmkX1XO0BdyzmrbcyzpFFQ== To: b.a.t.m.a.n@lists.open-mesh.org Cc: =?utf-8?q?Linus_L=C3=BCssing?= Subject: [PATCH maint v3 1/3] batman-adv: mcast: fix duplicate mcast packets in BLA backbone from LAN Date: Mon, 14 Sep 2020 03:21:34 +0200 Message-Id: <20200914012136.5278-2-linus.luessing@c0d3.blue> In-Reply-To: <20200914012136.5278-1-linus.luessing@c0d3.blue> References: <20200914012136.5278-1-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=1600046499; 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=SNnR/kQrMM/sLFu8uuD817v7EOHUbl4ZbaR+1+GWa40=; b=2tDZfdcMskdAk69vTzeqhWIQG0+2LdcoP1ZKwjr9cVBh3cbgFQ1gq0PPp80jrBITbvxETq GhvIUpQbC0xNVdN/gT14gc27Iq/xISjTKxHzS8qZfEE86z5ruIMOBg0VNfeen0jOYPHEIu IagwYzaF4icnimfq3kI49FOuyPaE+ks= ARC-Seal: i=1; s=20121; d=open-mesh.org; t=1600046499; a=rsa-sha256; cv=none; b=oRYf8PGFhNdtIpn6T4S0RB+me3lIhwc+Z8gmT6Sqr+xc8sNHpebCj6oKkevKmRxhZ/8psi CL6aZ84BPjOSnoAPjk1jdgJdfESHCcV9/7H98v70O8NjXmqPVqXjuspap3seHVDJH9yXyf 2tXW/z81+6dSFtourO7TLxaDBYN2aZI= ARC-Authentication-Results: i=1; diktynna.open-mesh.org; dkim=none (invalid DKIM record) header.d=c0d3.blue header.s=2018 header.b=Xe3ajBE2; 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: 6O3KMJACPSXSHKAYBGKDFS3LXPKKY6SO X-Message-ID-Hash: 6O3KMJACPSXSHKAYBGKDFS3LXPKKY6SO 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 a BLA backbone (multiple nodes with their bat0 bridged together, with BLA enabled) Issue: * BLA backbone nodes receive the frame multiple times on bat0 For multicast frames received via batman-adv broadcast packets the originator of the broadcast packet is checked before decapsulating and forwarding the frame to bat0 (batadv_bla_is_backbone_gw()-> batadv_recv_bcast_packet()). If it came from a node which shares the same BLA backbone with us then it is not forwarded to bat0 to avoid a loop. When sending a multicast frame in a non-4-address batman-adv unicast packet we are currently missing this check - and cannot do so because the batman-adv unicast packet has no originator address field. However, we can simply fix this on the sender side by only sending the multicast frame via unicasts to interested nodes which do not share the same BLA backbone with us. This also nicely avoids some unnecessary transmissions on mesh side. Note that no infinite loop was observed, probably because of dropping via batadv_interface_tx()->batadv_bla_tx(). However the duplicates still utterly confuse switches/bridges, ICMPv6 duplicate address detection and neighbor discovery and therefore leads to long delays before being able to establish TCP connections, for instance. And it also leads to the Linux bridge printing messages like: "br-lan: received packet on eth1 with own address as source address ..." Fixes: 405cc1e5a81e ("batman-adv: Modified forwarding behaviour for multicast packets") Signed-off-by: Linus Lüssing --- net/batman-adv/multicast.c | 46 ++++++++++++++++++++++++++------- net/batman-adv/multicast.h | 5 ++++ net/batman-adv/soft-interface.c | 5 ++-- 3 files changed, 43 insertions(+), 13 deletions(-) diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index bdc4a1fb..ca24a2e5 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -51,6 +51,7 @@ #include #include +#include "bridge_loop_avoidance.h" #include "hard-interface.h" #include "hash.h" #include "log.h" @@ -1434,6 +1435,35 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, return BATADV_FORW_ALL; } +/** + * batadv_mcast_forw_send_orig() - send a multicast packet to an originator + * @bat_priv: the bat priv with all the soft interface information + * @skb: the multicast packet to send + * @vid: the vlan identifier + * @orig_node: the originator to send the packet to + * + * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise. + */ +int batadv_mcast_forw_send_orig(struct batadv_priv *bat_priv, + struct sk_buff *skb, + unsigned short vid, + struct batadv_orig_node *orig_node) +{ + /* Avoid sending multicast-in-unicast packets to other BLA + * gateways - they already got the frame from the LAN side + * we share with them. + * TODO: Refactor to take BLA into account earlier, to avoid + * reducing the mcast_fanout count. + */ + if (batadv_bla_is_backbone_gw_orig(bat_priv, orig_node->orig, vid)) { + dev_kfree_skb(skb); + return NET_XMIT_SUCCESS; + } + + return batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST, 0, + orig_node, vid); +} + /** * batadv_mcast_forw_tt() - forwards a packet to multicast listeners * @bat_priv: the bat priv with all the soft interface information @@ -1471,8 +1501,8 @@ batadv_mcast_forw_tt(struct batadv_priv *bat_priv, struct sk_buff *skb, break; } - batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0, - orig_entry->orig_node, vid); + batadv_mcast_forw_send_orig(bat_priv, newskb, vid, + orig_entry->orig_node); } rcu_read_unlock(); @@ -1513,8 +1543,7 @@ batadv_mcast_forw_want_all_ipv4(struct batadv_priv *bat_priv, break; } - batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0, - orig_node, vid); + batadv_mcast_forw_send_orig(bat_priv, newskb, vid, orig_node); } rcu_read_unlock(); return ret; @@ -1551,8 +1580,7 @@ batadv_mcast_forw_want_all_ipv6(struct batadv_priv *bat_priv, break; } - batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0, - orig_node, vid); + batadv_mcast_forw_send_orig(bat_priv, newskb, vid, orig_node); } rcu_read_unlock(); return ret; @@ -1618,8 +1646,7 @@ batadv_mcast_forw_want_all_rtr4(struct batadv_priv *bat_priv, break; } - batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0, - orig_node, vid); + batadv_mcast_forw_send_orig(bat_priv, newskb, vid, orig_node); } rcu_read_unlock(); return ret; @@ -1656,8 +1683,7 @@ batadv_mcast_forw_want_all_rtr6(struct batadv_priv *bat_priv, break; } - batadv_send_skb_unicast(bat_priv, newskb, BATADV_UNICAST, 0, - orig_node, vid); + batadv_mcast_forw_send_orig(bat_priv, newskb, vid, orig_node); } rcu_read_unlock(); return ret; diff --git a/net/batman-adv/multicast.h b/net/batman-adv/multicast.h index ebf82599..08eb02c3 100644 --- a/net/batman-adv/multicast.h +++ b/net/batman-adv/multicast.h @@ -46,6 +46,11 @@ enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, struct batadv_orig_node **mcast_single_orig); +int batadv_mcast_forw_send_orig(struct batadv_priv *bat_priv, + struct sk_buff *skb, + unsigned short vid, + struct batadv_orig_node *orig_node); + int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb, unsigned short vid); diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 23833a0b..3d037b17 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -364,9 +364,8 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, goto dropped; ret = batadv_send_skb_via_gw(bat_priv, skb, vid); } else if (mcast_single_orig) { - ret = batadv_send_skb_unicast(bat_priv, skb, - BATADV_UNICAST, 0, - mcast_single_orig, vid); + ret = batadv_mcast_forw_send_orig(bat_priv, skb, vid, + mcast_single_orig); } else if (forw_mode == BATADV_FORW_SOME) { ret = batadv_mcast_forw_send(bat_priv, skb, vid); } else {