Re: [PATCH bpf-next v11 12/12] selftests/bpf: add simple bpf tests in the tx path for timestamping feature

[Martin KaFai Lau <martin.lau@linux.dev>]

On 2/13/25 5:00 PM, Jason Xing wrote:
> +static void test_recv_errmsg_cmsg(struct msghdr *msg)
> +{
> +	struct sock_extended_err *serr = NULL;
> +	struct scm_timestamping *tss = NULL;
> +	struct cmsghdr *cm;
> +
> +	for (cm = CMSG_FIRSTHDR(msg);
> +	     cm && cm->cmsg_len;
> +	     cm = CMSG_NXTHDR(msg, cm)) {
> +		if (cm->cmsg_level == SOL_SOCKET &&
> +		    cm->cmsg_type == SCM_TIMESTAMPING) {
> +			tss = (void *)CMSG_DATA(cm);
> +		} else if ((cm->cmsg_level == SOL_IP &&
> +			    cm->cmsg_type == IP_RECVERR) ||
> +			   (cm->cmsg_level == SOL_IPV6 &&
> +			    cm->cmsg_type == IPV6_RECVERR) ||
> +			   (cm->cmsg_level == SOL_PACKET &&
> +			    cm->cmsg_type == PACKET_TX_TIMESTAMP)) {
> +			serr = (void *)CMSG_DATA(cm);
> +			ASSERT_EQ(serr->ee_origin, SO_EE_ORIGIN_TIMESTAMPING,
> +				  "cmsg type");
> +		}
> +
> +		if (serr && tss)

Regarding this check, does it need to reset both serr and tss to NULL before the 
next iteration? e.g. It can get >1 timestamps in one recvmsg(MSG_ERRQUEUE) ?

> +			test_socket_timestamp(tss, serr->ee_info,
> +					      serr->ee_data);
> +	}
> +}
> +