[PATCH] net: tftp: Avoid sending extra ack on completion

[Suneel Garapati]

On Wed, Feb 3, 2021 at 12:05 AM Ramon Fried <rfried.dev at gmail.com> wrote:
>
> in tftpboot, if ack was already sent previously for this
> packet, don't send again.
>
> Fixes: cc6b87ecaa96 ("net: tftp: Add client support for RFC 7440")
>
> Reported-by: Suneel Garapati <suneelglinux at gmail.com>
> Signed-off-by: Ramon Fried <rfried.dev at gmail.com>
> ---
>  net/tftp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/tftp.c b/net/tftp.c
> index 03079ded34..1111834f71 100644
> --- a/net/tftp.c
> +++ b/net/tftp.c
> @@ -678,7 +678,8 @@ static void tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
>                 }
>
>                 if (len < tftp_block_size) {
> -                       tftp_send();
> +                       if (tftp_cur_block != tftp_next_ack)
> +                               tftp_send();
In the 'if' block above this, next_ack is incremented by window size
already, so for size 1 this condition is always true.
And the extra ack is sent.

>                         tftp_complete();
>                 }
>                 break;
> --
> 2.17.1
>