From owner-freebsd-net@FreeBSD.ORG Thu Aug 2 22:15:26 2007 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DD0F016A419 for ; Thu, 2 Aug 2007 22:15:26 +0000 (UTC) (envelope-from jfvogel@gmail.com) Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.180]) by mx1.freebsd.org (Postfix) with ESMTP id B1E8B13C483 for ; Thu, 2 Aug 2007 22:15:26 +0000 (UTC) (envelope-from jfvogel@gmail.com) Received: by wa-out-1112.google.com with SMTP id k17so693315waf for ; Thu, 02 Aug 2007 15:15:26 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=puA7rADe9kY9cBkfy25/IzpHg7HDFYBhaNhbez1hZxmABO66CbXXBpLUxBVpO7QhjmnwuRrpO16NG4QwqKIrQtgrhRWrUSLAbo/MVE63rIh3js/mfr8ueag7gmfVJR5rBktzFFD4QLUKaRGiVpKy7rkR4wDntbRn+uS9Rc53eMY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=VLQg5HXRco0iNuMWJYKJEhDQ48Sph4t//GZJjDjpBTTRSekVlrnAKllqZ2gOSZaRg2DivVuc1P/dGw9297F5zHb9qMnK1mrgIsl7KK6WjosQZe0PARpRbLfyXSYGNNTUrzX3YQES0m1jlvT5UaxC8yWYWdwHauirT+7ncvDSnpY= Received: by 10.114.198.1 with SMTP id v1mr2300065waf.1186092923343; Thu, 02 Aug 2007 15:15:23 -0700 (PDT) Received: by 10.114.103.14 with HTTP; Thu, 2 Aug 2007 15:15:23 -0700 (PDT) Message-ID: <2a41acea0708021515v118a6087ge6ddbfe415cb3774@mail.gmail.com> Date: Thu, 2 Aug 2007 15:15:23 -0700 From: "Jack Vogel" To: "Andre Oppermann" , "freebsd-net@freebsd.org" In-Reply-To: <2a41acea0708021444o7edc4ecetb08601fa18ad43ea@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <2a41acea0708021444o7edc4ecetb08601fa18ad43ea@mail.gmail.com> Cc: Subject: Re: Odd driver behavior with IPV6 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Aug 2007 22:15:26 -0000 On 8/2/07, Jack Vogel wrote: > I have some behavior I don't understand, perhaps someone can enlighten me. > > There is a difference in behavior between the em driver and ixgbe, but I can > not figure out what it is, here is the behavior. > > With em driver, you can give the interface an ipv6 address, and set mtu > to 9000, then when you 'route get -inet6 ipv6host' it will show the mtu > to be 9000, this is what you would expect. > > OK, the problem is that with ixgbe, when it is built in OR when it is set > to load immediately on boot it works correctly, BUT, if I just randomly > load the driver after coming up, and then do the above steps, when you > do the route get the MTU shows up only as 1500. This works correctly > for IPv4 which is why this mystifies me, the driver doesnt have any > code for IP versions. > > I hope this explanation is clear. Anyone have a clue? I have some more data, in setup, after the call to ether_ifattach(), the ixgbe driver explicitly does ifp->if_mtu = 9000 to change the default. If I take this out then this all works, but I don't understand why this should be, especially since if the code is static in the kernel it works. Very strange :( Jack PS. BTW, the mxge does this as well, Drew you might want to check if this happens for you.