• Shaun Pereira's avatar
    [X25]: allow ITU-T DTE facilities for x25 · a64b7b93
    Shaun Pereira authored
    Allows use of the optional user facility to insert ITU-T
    (http://www.itu.int/ITU-T/) specified DTE facilities in call set-up x25
    packets.  This feature is optional; no facilities will be added if the ioctl
    is not used, and call setup packet remains the same as before.
    
    If the ioctls provided by the patch are used, then a facility marker will be
    added to the x25 packet header so that the called dte address extension
    facility can be differentiated from other types of facilities (as described in
    the ITU-T X.25 recommendation) that are also allowed in the x25 packet header.
    
    Facility markers are made up of two octets, and may be present in the x25
    packet headers of call-request, incoming call, call accepted, clear request,
    and clear indication packets.  The first of the two octets represents the
    facility code field and is set to zero by this patch.  The second octet of the
    marker represents the facility parameter field and is set to 0x0F because the
    marker will be inserted before ITU-T type DTE facilities.
    
    Since according to ITU-T X.25 Recommendation X.25(10/96)- 7.1 "All networks
    will support the facility markers with a facility parameter field set to all
    ones or to 00001111", therefore this patch should work with all x.25 networks.
    
    While there are many ITU-T DTE facilities, this patch implements only the
    called and calling address extension, with placeholders in the
    x25_dte_facilities structure for the rest of the facilities.
    
    Testing:
    
    This patch was tested using a cisco xot router connected on its serial ports
    to an X.25 network, and on its lan ports to a host running an xotd daemon.
    
    It is also possible to test this patch using an xotd daemon and an x25tap
    patch, where the xotd daemons work back-to-back without actually using an x.25
    network.  See www.fyonne.net for details on how to do this.
    Signed-off-by: default avatarShaun Pereira <spereira@tusc.com.au>
    Acked-by: default avatarAndrew Hendry <ahendry@tusc.com.au>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a64b7b93
x25.h 3.34 KB