Re: [PATCH v6 net-next 04/14] selftests/net: gro: add self-test for TCP CWR flag

[Paolo Abeni <pabeni@redhat.com>]

On 11/14/25 8:13 AM, chia-yu.chang@nokia-bell-labs.com wrote:
> +/* send extra flags of the (NUM_PACKETS / 2) and (NUM_PACKETS / 2 - 1)
> + * pkts, not first and not last pkt
> + */
> +static void send_flags(int fd, struct sockaddr_ll *daddr, int psh, int syn,
> +		       int rst, int urg, int cwr)
> +{
> +	static char flag_buf[2][MAX_HDR_LEN + PAYLOAD_LEN];
> +	static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
> +	int payload_len, pkt_size, i;
> +	struct tcphdr *tcph;
> +	int flag[2];
> +
> +	payload_len = PAYLOAD_LEN * (psh || cwr);
> +	pkt_size = total_hdr_len + payload_len;
> +	flag[0] = NUM_PACKETS / 2;
> +	flag[1] = NUM_PACKETS / 2 - 1;
> +
> +	// Create and configure packets with flags

Please use /* */ for comments.

Other than that:

Acked-by: Paolo Abeni <pabeni@redhat.com>

> +	for (i = 0; i < 2; i++) {
> +		if (flag[i] > 0) {
> +			create_packet(flag_buf[i], flag[i] * payload_len, 0,
> +				      payload_len, 0);
> +			tcph = (struct tcphdr *)(flag_buf[i] + tcp_offset);
> +			set_flags(tcph, payload_len, psh, syn, rst, urg, cwr);
> +		}
> +	}
>  
>  	for (i = 0; i < NUM_PACKETS + 1; i++) {
> -		if (i == flag) {
> -			write_packet(fd, flag_buf, pkt_size, daddr);
> +		if (i == flag[0]) {
> +			write_packet(fd, flag_buf[0], pkt_size, daddr);
> +			continue;
> +		} else if (i == flag[1] && cwr) {
> +			write_packet(fd, flag_buf[1], pkt_size, daddr);
>  			continue;
>  		}
>  		create_packet(buf, i * PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
> @@ -1020,16 +1045,19 @@ static void gro_sender(void)
>  		send_ack(txfd, &daddr);
>  		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
>  	} else if (strcmp(testname, "flags") == 0) {
> -		send_flags(txfd, &daddr, 1, 0, 0, 0);
> +		send_flags(txfd, &daddr, 1, 0, 0, 0, 0);
>  		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
>  
> -		send_flags(txfd, &daddr, 0, 1, 0, 0);
> +		send_flags(txfd, &daddr, 0, 1, 0, 0, 0);
>  		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
>  
> -		send_flags(txfd, &daddr, 0, 0, 1, 0);
> +		send_flags(txfd, &daddr, 0, 0, 1, 0, 0);
>  		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
>  
> -		send_flags(txfd, &daddr, 0, 0, 0, 1);
> +		send_flags(txfd, &daddr, 0, 0, 0, 1, 0);
> +		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
> +
> +		send_flags(txfd, &daddr, 0, 0, 0, 0, 1);
>  		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
>  	} else if (strcmp(testname, "tcp") == 0) {
>  		send_changed_checksum(txfd, &daddr);
> @@ -1163,6 +1191,12 @@ static void gro_receiver(void)
>  
>  		printf("urg flag ends coalescing: ");
>  		check_recv_pkts(rxfd, correct_payload, 3);
> +
> +		correct_payload[0] = PAYLOAD_LEN;
> +		correct_payload[1] = PAYLOAD_LEN * 2;
> +		correct_payload[2] = PAYLOAD_LEN * 2;
> +		printf("cwr flag ends coalescing: ");
> +		check_recv_pkts(rxfd, correct_payload, 3);
>  	} else if (strcmp(testname, "tcp") == 0) {
>  		correct_payload[0] = PAYLOAD_LEN;
>  		correct_payload[1] = PAYLOAD_LEN;