From: Martin Schiller
> Sent: 24 November 2020 09:36
>
> 1. DTE interface changes immediately to LAPB_STATE_1 and start sending
> SABM(E).
>
> 2. DCE interface sends N2-times DM and changes to LAPB_STATE_1
> afterwards if there is no response in the meantime.
Seems reasonable.
It is 35 years since I wrote LAPB and I can't exactly remember
what we did.
If I stole a copy of the code it's on a QIC-150 tape cartridge!
I really don't remember having a DTE/DCE option.
It is likely that LAPB came up sending DM (response without F)
until level3 requested the link come up when it would send
N2 SABM+P hoping to get a UA+F.
It would then send DM-F until a retry request was made.
We certainly had several different types of crossover connectors
for DTE-DTE working.
David
>
> Signed-off-by: Martin Schiller <ms@xxxxxxxxxx>
> ---
> net/lapb/lapb_timer.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/net/lapb/lapb_timer.c b/net/lapb/lapb_timer.c
> index 8f5b17001a07..baa247fe4ed0 100644
> --- a/net/lapb/lapb_timer.c
> +++ b/net/lapb/lapb_timer.c
> @@ -85,11 +85,18 @@ static void lapb_t1timer_expiry(struct timer_list *t)
> switch (lapb->state) {
>
> /*
> - * If we are a DCE, keep going DM .. DM .. DM
> + * If we are a DCE, send DM up to N2 times, then switch to
> + * STATE_1 and send SABM(E).
> */
> case LAPB_STATE_0:
> - if (lapb->mode & LAPB_DCE)
> + if (lapb->mode & LAPB_DCE &&
> + lapb->n2count != lapb->n2) {
> + lapb->n2count++;
> lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
> + } else {
> + lapb->state = LAPB_STATE_1;
> + lapb_establish_data_link(lapb);
> + }
> break;
>
> /*
> --
> 2.20.1
-
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