[LTP] [PATCH 2/2] pty04: use the correct protocol per line discipline to avoid extra packets

[Petr Vorel]

Hi Vasileios,

> Use specific protocol filter (ETH_P_IP for N_SLIP, ETH_P_CAN for N_SLCAN)
> instead of ETH_P_ALL to avoid catching unrelated packets like IPv6
> multicast (MLD) which cause false test failures.

LGTM.
@Martin: could you please double check?

Reviewed-by: Petr Vorel <pvorel@suse.cz>

Kind regards,
Petr

> Signed-off-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
> ---
>  testcases/kernel/pty/pty04.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)

> diff --git a/testcases/kernel/pty/pty04.c b/testcases/kernel/pty/pty04.c
> index 204703253..770c053c4 100644
> --- a/testcases/kernel/pty/pty04.c
> +++ b/testcases/kernel/pty/pty04.c
> @@ -258,6 +258,19 @@ static void open_netdev(const struct ldisc_info *ldisc)
>  {
>  	struct ifreq ifreq = { 0 };
>  	struct sockaddr_ll lla = { 0 };
> +	int protocol;
> +
> +	switch (ldisc->n) {
> +		case N_SLIP:
> +			protocol = ETH_P_IP;
> +			break;
> +		case N_SLCAN:
> +			protocol = ETH_P_CAN;
> +			break;
> +		default:
> +			protocol = ETH_P_ALL;
> +			break;
> +	}

>  	SAFE_IOCTL(pts, SIOCGIFNAME, ifreq.ifr_name);
>  	tst_res(TINFO, "Netdev is %s", ifreq.ifr_name);
> @@ -282,7 +295,7 @@ static void open_netdev(const struct ldisc_info *ldisc)
>  	SAFE_IOCTL(sk, SIOCGIFINDEX, &ifreq);

>  	lla.sll_family = PF_PACKET;
> -	lla.sll_protocol = htons(ETH_P_ALL);
> +	lla.sll_protocol = htons(protocol);
>  	lla.sll_ifindex = ifreq.ifr_ifindex;
>  	SAFE_BIND(sk, (struct sockaddr *)&lla, sizeof(struct sockaddr_ll));