Re: [PATCH net-next 1/3] net-timestamp: add strict check when setting tx flags

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 30/09/2024 10:24, Jason Xing wrote:
> From: Jason Xing <kernelxing@tencent.com>
> 
> Even though this case is unlikely to happen, we have to avoid such
> a case occurring at an earlier point: the sk_rmem_alloc could get
> increased because of inserting more and more skbs into the errqueue
> when calling __skb_complete_tx_timestamp(). This bad case would stop
> the socket transmitting soon.
> 
> Signed-off-by: Jason Xing <kernelxing@tencent.com>
> ---
>   net/core/sock.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/net/core/sock.c b/net/core/sock.c
> index fe87f9bd8f16..4bddd6f62e4f 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -905,6 +905,10 @@ int sock_set_timestamping(struct sock *sk, int optname,
>   	if (val & ~SOF_TIMESTAMPING_MASK)
>   		return -EINVAL;
>   
> +	if (val & SOF_TIMESTAMPING_TX_RECORD_MASK &&
> +	    !(val & SOF_TIMESTAMPING_SOFTWARE))
> +		return -EINVAL;

SOF_TIMESTAMPING_TX_RECORD_MASK contains SOF_TIMESTAMPING_TX_HARDWARE.
That means that there will be no option to enable HW TX timestamping
without enabling software timestamping. I believe this is wrong
restriction.

> +
>   	if (val & SOF_TIMESTAMPING_OPT_ID_TCP &&
>   	    !(val & SOF_TIMESTAMPING_OPT_ID))
>   		return -EINVAL;