[lwip-users] [lwip] Why ack packets are not sent when snd_wnd is zero?

[Mumtaz Ahmad]

in tcp_output we send tcp segements only if the snd_wnd is greater than zero
though TCP RFC allows to send ACKs even when the receiver window is zero .
Why is it so?

I think it might result in memory leak in some scenarios like
        if we send a delayed ack but the snd_wnd is zero . We have already
allocated a seg and pbuf for it but could not empty pcb->unsent . If the
receiver window remains zero for long time then on next timer expiry we
would generate another delayed ack packet which would  overwrite the
pcb->unsent .Now there is no information stored about the old ACK segement
and it might be a memory leak.

am i missiong something ??

Regards
Mumtaz Ahmad



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