Ensure we can never integer wrap when working on client-supplied max_data_bytes.

This would only be possible with SMB2, and is already checked in the upper
SMB2 layers, but it really doesn't hurt to have these extra checks at time
of use also.

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: David Disseldorp <ddiss@samba.org>

Autobuild-User(master): David Disseldorp <ddiss@samba.org>
Autobuild-Date(master): Sun Aug  4 16:54:04 CEST 2013 on sn-devel-104
tevent: Add echo server sample code

This is under a deliberately permissive license. I would like people to start
using libtevent and tevent_req (LGPL) without any worries about where to start
from.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

Autobuild-User(master): Amitay Isaacs <amitay@samba.org>
Autobuild-Date(master): Mon Aug  5 04:07:58 CEST 2013 on sn-devel-104