[PATCH rtems-libbsd] ppp: Fix transmitting data

[Gedare Bloom]

looks ok, but hold until chris pushes his big patches through I think.
(Not that it should conflict, but I think it will be better this way.)

On Thu, Aug 12, 2021 at 5:42 AM Christian Mauderer
<christian.mauderer at embedded-brains.de> wrote:
>
> The pppstart expected that a driver write would somehow magically
> process all data passed to the write function. Because ppp disables all
> buffering that originally has been in termios, that assumption is not
> true for all but polled drivers.
>
> With this patch, the pppstart now gets and processes the feedback that
> is returned from the driver via rtems_termios_dequeue_characters.
>
> Fixes #4493
> ---
>  rtemsbsd/sys/net/if_ppp.c    | 11 ++++++-----
>  rtemsbsd/sys/net/if_pppvar.h |  1 +
>  rtemsbsd/sys/net/ppp_tty.c   | 32 ++++++++++++++++++++++++++++----
>  3 files changed, 35 insertions(+), 9 deletions(-)
>
> diff --git a/rtemsbsd/sys/net/if_ppp.c b/rtemsbsd/sys/net/if_ppp.c
> index 709f13e04..e134dc760 100644
> --- a/rtemsbsd/sys/net/if_ppp.c
> +++ b/rtemsbsd/sys/net/if_ppp.c
> @@ -313,11 +313,12 @@ static rtems_task ppp_txdaemon(rtems_task_argument arg)
>        frag=0;
>
>        /* initialize output values */
> -      sc->sc_outfcs    = PPP_INITFCS;
> -      sc->sc_outbuf    = (u_char *)0;
> -      sc->sc_outlen    = (short   )0;
> -      sc->sc_outoff    = (short   )0;
> -      sc->sc_outfcslen = (short   )0;
> +      sc->sc_outfcs        = PPP_INITFCS;
> +      sc->sc_outbuf        = (u_char *)0;
> +      sc->sc_outlen        = (short   )0;
> +      sc->sc_outoff        = (short   )0;
> +      sc->sc_outoff_update = false;
> +      sc->sc_outfcslen     = (short   )0;
>
>  /*       printf("Start Transmit Packet..\n"); */
>
> diff --git a/rtemsbsd/sys/net/if_pppvar.h b/rtemsbsd/sys/net/if_pppvar.h
> index fdfb56df0..bd11bcbc4 100644
> --- a/rtemsbsd/sys/net/if_pppvar.h
> +++ b/rtemsbsd/sys/net/if_pppvar.h
> @@ -117,6 +117,7 @@ struct ppp_softc {
>
>         struct  ifqueue sc_freeq;       /* free packets */
>         short   sc_outoff;              /* output packet byte offset */
> +       bool    sc_outoff_update;       /* outoff needs update in pppstart */
>         short   sc_outflag;             /* output status flag */
>         short   sc_outlen;              /* length of output packet */
>         short   sc_outfcslen;           /* length of output fcs data */
> diff --git a/rtemsbsd/sys/net/ppp_tty.c b/rtemsbsd/sys/net/ppp_tty.c
> index 80d4fee16..2e850dc77 100644
> --- a/rtemsbsd/sys/net/ppp_tty.c
> +++ b/rtemsbsd/sys/net/ppp_tty.c
> @@ -124,7 +124,7 @@ int     pppread(struct rtems_termios_tty *tty, rtems_libio_rw_args_t *rw_args);
>  int     pppwrite(struct rtems_termios_tty *tty, rtems_libio_rw_args_t *rw_args);
>  int     ppptioctl(struct rtems_termios_tty *tty, rtems_libio_ioctl_args_t *args);
>  int     pppinput(int c, struct rtems_termios_tty *tty);
> -int     pppstart(struct rtems_termios_tty *tp);
> +int     pppstart(struct rtems_termios_tty *tp, int len);
>  u_short pppfcs(u_short fcs, u_char *cp, int len);
>  void    pppallocmbuf(struct ppp_softc *sc, struct mbuf **mp);
>
> @@ -557,7 +557,7 @@ pppasyncctlp(
>   * Called at spltty or higher.
>   */
>  int
> -pppstart(struct rtems_termios_tty *tp)
> +pppstart(struct rtems_termios_tty *tp, int len)
>  {
>    u_char             *sendBegin;
>    u_long              ioffset = (u_long       )0;
> @@ -567,6 +567,13 @@ pppstart(struct rtems_termios_tty *tp)
>
>    /* ensure input is valid and we are busy */
>    if (( sc != NULL ) && ( sc->sc_outflag & SC_TX_BUSY )) {
> +    /* Adapt offsets if necessary */
> +    if ( sc->sc_outoff_update ) {
> +      sc->sc_stats.ppp_obytes += len;
> +      sc->sc_outoff += len;
> +      sc->sc_outoff_update = false;
> +    }
> +
>      /* check to see if we need to get the next buffer */
>
>      /* Ready with PPP_FLAG Character ? */
> @@ -644,8 +651,25 @@ pppstart(struct rtems_termios_tty *tp)
>
>        /* write out the character(s) and update the stats */
>        (*tp->handler.write)(ctx, (char *)sendBegin, (ioffset > 0) ? ioffset : 1);
> -      sc->sc_stats.ppp_obytes += (ioffset > 0) ? ioffset : 1;
> -      sc->sc_outoff += ioffset;
> +      /*
> +       * In case of polled drivers, everything is sent here. So adapt the
> +       * offsets. In case of interrupt or task driven drivers, we don't know
> +       * whether all characters have been sent. We only get feedback via
> +       * rtems_termios_dequeue_characters() function which is the one that is
> +       * calling us.
> +       */
> +      if (tp->handler.mode == TERMIOS_POLLED) {
> +        sc->sc_stats.ppp_obytes += (ioffset > 0) ? ioffset : 1;
> +        sc->sc_outoff += ioffset;
> +        sc->sc_outoff_update = false;
> +      } else {
> +        if (ioffset > 0) {
> +          sc->sc_outoff_update = true;
> +        } else {
> +          sc->sc_outoff_update = false;
> +          sc->sc_stats.ppp_obytes += 1;
> +        }
> +      }
>
>        return (0);
>      }
> --
> 2.31.1
>
> _______________________________________________
> devel mailing list
> devel at rtems.org
> http://lists.rtems.org/mailman/listinfo/devel