Re: [PATCH v3 12/13] can: slcan: extend the protocol with error info
From: Dario Binacchi
Date: Mon Jun 13 2022 - 17:21:41 EST
On Mon, Jun 13, 2022 at 9:32 AM Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> wrote:
>
> On 12.06.2022 23:39:26, Dario Binacchi wrote:
> > It extends the protocol to receive the adapter CAN communication errors
> > and forward them to the netdev upper levels.
> >
> > Signed-off-by: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
> >
> > ---
> >
> > (no changes since v2)
> >
> > Changes in v2:
> > - Protect decoding against the case the len value is longer than the
> > received data.
>
> Where is that check?
I added the default case in the switch statement. Each line that is
processed by slc_bump_err()
is terminated by a '\r' or '\a' character. If len value is longer than
the received characters, it will
enter the default case for the eol character and the function will return.
But I realize now that I am wrong, the terminator is not placed in the
buffer passed to slc_bump_err() !!!!!! :)
I will add the right check in v4.
Thanks and regards,
Dario
>
> > - Continue error handling even if no skb can be allocated.
> >
> > drivers/net/can/slcan/slcan-core.c | 130 ++++++++++++++++++++++++++++-
> > 1 file changed, 129 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
> > index 3df35ae8f040..48077edb9497 100644
> > --- a/drivers/net/can/slcan/slcan-core.c
> > +++ b/drivers/net/can/slcan/slcan-core.c
> > @@ -175,8 +175,118 @@ int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on)
> > * STANDARD SLCAN DECAPSULATION *
> > ************************************************************************/
> >
> > +static void slc_bump_err(struct slcan *sl)
> > +{
> > + struct net_device *dev = sl->dev;
> > + struct sk_buff *skb;
> > + struct can_frame *cf;
> > + char *cmd = sl->rbuff;
> > + bool rx_errors = false, tx_errors = false;
> > + int i, len;
> > +
> > + if (*cmd != 'e')
> > + return;
>
> This has already been checked in the caller, right?
>
> > +
> > + cmd += SLC_CMD_LEN;
> > + /* get len from sanitized ASCII value */
> > + len = *cmd++;
> > + if (len >= '0' && len < '9')
> > + len -= '0';
> > + else
> > + return;
> > +
> > + skb = alloc_can_err_skb(dev, &cf);
> > +
> > + if (skb)
> > + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> > +
> > + for (i = 0; i < len; i++, cmd++) {
> > + switch (*cmd) {
> > + case 'a':
> > + netdev_dbg(dev, "ACK error\n");
> > + tx_errors = true;
>
> Nitpick:
> Please decide if you want to set tx/tx_errors here and increment at the
> end of the function....or.....
>
> > + if (skb) {
> > + cf->can_id |= CAN_ERR_ACK;
> > + cf->data[3] = CAN_ERR_PROT_LOC_ACK;
> > + }
> > +
> > + break;
> > + case 'b':
> > + netdev_dbg(dev, "Bit0 error\n");
> > + tx_errors = true;
> > + if (skb)
> > + cf->data[2] |= CAN_ERR_PROT_BIT0;
> > +
> > + break;
> > + case 'B':
> > + netdev_dbg(dev, "Bit1 error\n");
> > + tx_errors = true;
> > + if (skb)
> > + cf->data[2] |= CAN_ERR_PROT_BIT1;
> > +
> > + break;
> > + case 'c':
> > + netdev_dbg(dev, "CRC error\n");
> > + rx_errors = true;
> > + if (skb) {
> > + cf->data[2] |= CAN_ERR_PROT_BIT;
> > + cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
> > + }
> > +
> > + break;
> > + case 'f':
> > + netdev_dbg(dev, "Form Error\n");
> > + rx_errors = true;
> > + if (skb)
> > + cf->data[2] |= CAN_ERR_PROT_FORM;
> > +
> > + break;
> > + case 'o':
> > + netdev_dbg(dev, "Rx overrun error\n");
> > + dev->stats.rx_over_errors++;
> > + dev->stats.rx_errors++;
>
> ....if you want to increment in the case.
>
> > + if (skb) {
> > + cf->can_id |= CAN_ERR_CRTL;
> > + cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> > + }
> > +
> > + break;
> > + case 'O':
> > + netdev_dbg(dev, "Tx overrun error\n");
> > + dev->stats.tx_errors++;
> > + if (skb) {
> > + cf->can_id |= CAN_ERR_CRTL;
> > + cf->data[1] = CAN_ERR_CRTL_TX_OVERFLOW;
> > + }
> > +
> > + break;
> > + case 's':
> > + netdev_dbg(dev, "Stuff error\n");
> > + rx_errors = true;
> > + if (skb)
> > + cf->data[2] |= CAN_ERR_PROT_STUFF;
> > +
> > + break;
> > + default:
> > + if (skb)
> > + dev_kfree_skb(skb);
> > +
> > + return;
> > + }
> > + }
> > +
> > + if (rx_errors)
> > + dev->stats.rx_errors++;
> > +
> > + if (tx_errors)
> > + dev->stats.tx_errors++;
> > +
> > + if (skb)
> > + netif_rx(skb);
> > +}
> > +
> > /* Send one completely decapsulated can_frame to the network layer */
> > -static void slc_bump(struct slcan *sl)
> > +static void slc_bump_frame(struct slcan *sl)
> > {
> > struct sk_buff *skb;
> > struct can_frame *cf;
> > @@ -255,6 +365,24 @@ static void slc_bump(struct slcan *sl)
> > dev_kfree_skb(skb);
> > }
> >
> > +static void slc_bump(struct slcan *sl)
> > +{
> > + switch (sl->rbuff[0]) {
> > + case 'r':
> > + fallthrough;
> > + case 't':
> > + fallthrough;
> > + case 'R':
> > + fallthrough;
> > + case 'T':
> > + return slc_bump_frame(sl);
> > + case 'e':
> > + return slc_bump_err(sl);
> > + default:
> > + return;
> > + }
> > +}
> > +
> > /* parse tty input stream */
> > static void slcan_unesc(struct slcan *sl, unsigned char s)
> > {
> > --
> > 2.32.0
> >
> >
>
> Marc
>
> --
> Pengutronix e.K. | Marc Kleine-Budde |
> Embedded Linux | https://www.pengutronix.de |
> Vertretung West/Dortmund | Phone: +49-231-2826-924 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
--
Dario Binacchi
Embedded Linux Developer
dario.binacchi@xxxxxxxxxxxxxxxxxxxx
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