Re: Working on howl port

From: Andrea Campi (andrea+freebsd_net_at_webcom.it)
Date: 12/12/04

  • Next message: Peter Heerboth: "Re: Working on howl port" 
    Date: Sun, 12 Dec 2004 00:14:34 +0100
To: Chuck Swiger <cswiger@mac.com>

    On Sat, Dec 11, 2004 at 03:56:33PM -0500, Chuck Swiger wrote:
    > >Just to check my assumptions: is it reasonable to assume autoipd
    > >has total control over the 169.254 block? I don't want to have to
    > >bother about preserving any existing address in that range etc.
    >
    > No, it is not reasonable. Although if you make that assumption for the
    > first implementation, it's probably mostly harmless again. However,

    Ah no, I meant on the local machine. What I mean is that by running
    zeroconf the user is giving total control of that block, and in
    particular is going to avoid explicitely configuring an interface
    with such an address. I figure that's quite reasonable.

    > Anyway, perhaps my responses would be more helpful if you explained the use
    > case you are trying to get going, first?

    Unless I'm mistaken, using SIOCAIFADDR instead of SIOCSIFADDR means
    that I do need to bother about other addresses in the same network
    on the same or on another interface. My plan is to replace any
    such address as needed, as long as I can trust they are not of any
    special meaning to the user.

    Additionally, if I can expect the user not to set a 169.254 address,
    I can assume RTM_ADD/RTM_NEWADDR messages for such an address come
    from dhclient failing to get a lease. Think of this scenario:

     - unconnected laptop on a bus, I get an addess by zeroconf;
     - I arrive at the office and the DHCP server gives out an address,
    zeroconf goes to sleep;
     - the DHCP server dies and come renew time dhclient notices and
    sets a 169.254 address.

    I'd like to be able to notice this case and decide it's really
    dhclient trying to tell me something, and not have to worry about
    a user trying to set a random IP address.

    Anyway, thinking again, this is probably less important than I
    first thought. I'm mostly thinking out aloud here. It just
    occurred to me that the second part can probably be better
    dealt with by having an useful set of scripts for dhclient.

    I think I should now get some more steps and expecially tests
    done, and come back when I have a clearer idea of how they
    interact. I'll still post some interim steps for feedback on
    the implementation.

    Bye,
            Andrea 

    -- 
            Give a man a fish and you feed him for a day;
     teach him to use the Net and he won't bother you for weeks.
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  • Next message: Peter Heerboth: "Re: Working on howl port"