From mboxrd@z Thu Jan 1 00:00:00 1970 From: Casey Carter Subject: Re: RFC1323. No timestamping if SYN timestamp = 0. Bug or Feature? Date: Fri, 24 Oct 2003 08:16:13 -0500 Sender: netdev-bounce@oss.sgi.com Message-ID: <3F99261D.5030008@Carter.net> References: <20031022200152.17005.qmail@web13006.mail.yahoo.com> <20031023013748.0dd168db.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Bartek Wydrowski , netdev@oss.sgi.com, kuznet@ms2.inr.ac.ru Return-path: To: "David S. Miller" In-Reply-To: <20031023013748.0dd168db.davem@redhat.com> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org David S. Miller wrote: >It is impossible to comply to RFC1323 if we allow TSval in the >initial SYN packet to be zero, from RFC1323: > > When TSecr is not valid, its value must be zero. > >It is therefore impossible to accept TSval as zero, because >our TSecr echo of that timestamp would be also zero and thus >invalid. > >That is why we reject zero timestamps in the initial SYN packet. > > Note that the text does not say "When TSecr is zero, it is invalid." You are reversing the conditional statement "not valid implies zero" to "zero implies not valid." I don't think that the intent of this text in the RFC is to forbid the use of zero as a timestamp, but only to assert that the value should be set to zero by default. -- Casey Carter Casey@Carter.net ccarter@cs.uiuc.edu AIM: cartec69