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    SubjectRe: 2.2.13 ISDN funnies
    >>>>> "Alan" == Alan Cox <> writes:

    >> I heared similar problems with ppp over ethernet and normal
    >> ppp.

    Alan> There was a sign bug months ago with this that bit Alpha
    Alan> users for one. That was fixed. Other than that we haven't
    Alan> seen anything. So right now I believe the bug is in the isdn

    Maybe there is still another bug in ip_output.c::ip_queue_xmit():
    There, the re-allocation of header space is only done if the
    device has a dev->hard_header() method:

    if (skb_headroom(skb) < dev->hard_header_len && dev->hard_header) {
    struct sk_buff *skb2;

    skb2 = skb_realloc_headroom(skb, (dev->hard_header_len + 15) & ~

    Async ppp in 2.2.x as well as the generic ppp in 2.3.x have no
    dev->hard_header() method. Karsten's routing scenario
    (e.g. from slip or raw hdlc device to ppp-over-ethernet) will result in
    header space growing larger then the implict space of 16 byte
    as provided by dev_alloc_skb(). Now, if ip_output does not reallocate
    headroom because ppp has no dev->hard_header() method, problems might


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      Last update: 2005-03-22 13:54    [W:0.025 / U:13.956 seconds]
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