From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VM5a29fqP95S1lJxPMUQbYsDCLKj49ryy4WzRwBltm0=; b=YP7lSbEoon+8DAygCdWSk1yRFfssjGAZL1y6hjnyrcEwt8+WOVr/7LzRLlsccRuLUd RBVYyOEBqY4CXP+UIcu2tFZNl8uiKTdPa3CYJnYcDyhoO/KEPapnWdrP6bJmWihOscxD yDrjPhyIQ4DVOVmYExxc2F5qhuaSKhkDh8W0+wUt2XC9dTwywPuxXdtu+0NCJsBpdOJC SYAyhxW9ugkbkYXDj9DXsxXyLh3dXy+5bydmBl9bqFuIr/BmXEKU/o269j7knp8EApIw ik9AnM/pWKUJjemyFLq/ZQD1AQTbmy+7Pb1fh/hVBLZlOhDYw7XoZCuJPRlxjlVysI4p BbXw== Date: Tue, 9 May 2017 08:49:28 -0700 From: Stephen Hemminger Message-ID: <20170509084928.4cfcbda5@xeon-e3> In-Reply-To: <20170509124439.45674-1-fredrik.markstrom@gmail.com> References: <20170509124439.45674-1-fredrik.markstrom@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Bridge] [PATCH 0/2] net: Set maximum receive packet size on veth interfaces List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fredrik Markstrom Cc: Eric Dumazet , Daniel Borkmann , netdev@vger.kernel.org, bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Alexei Starovoitov , "David S. Miller" On Tue, 9 May 2017 14:44:36 +0200 Fredrik Markstrom wrote: > Currently veth drops all packets larger then the mtu set on the receiving > end of the pair. This is inconsistent with most hardware ethernet drivers. There is no guarantee that packets larger than MTU + VLAN tag will be received by hardware drivers. So why is this necessary for veth? What is your special use case which makes this necessary? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754652AbdEIPtd (ORCPT ); Tue, 9 May 2017 11:49:33 -0400 Received: from mail-pf0-f175.google.com ([209.85.192.175]:34529 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754570AbdEIPtb (ORCPT ); Tue, 9 May 2017 11:49:31 -0400 Date: Tue, 9 May 2017 08:49:28 -0700 From: Stephen Hemminger To: Fredrik Markstrom Cc: Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bridge@lists.linux-foundation.org Subject: Re: [PATCH 0/2] net: Set maximum receive packet size on veth interfaces Message-ID: <20170509084928.4cfcbda5@xeon-e3> In-Reply-To: <20170509124439.45674-1-fredrik.markstrom@gmail.com> References: <20170509124439.45674-1-fredrik.markstrom@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 9 May 2017 14:44:36 +0200 Fredrik Markstrom wrote: > Currently veth drops all packets larger then the mtu set on the receiving > end of the pair. This is inconsistent with most hardware ethernet drivers. There is no guarantee that packets larger than MTU + VLAN tag will be received by hardware drivers. So why is this necessary for veth? What is your special use case which makes this necessary?