Re: [mptcp-next v4 1/2] selftests: mptcp: Add a tool to get specific msk_info

[Matthieu Baerts <matttbe@kernel.org>]

Hi Gang Yan,

On 24/02/2025 10:02, Gang Yan wrote:
> This patch enables the retrieval of the mptcp_info structure corresponding
> to a specified MPTCP socket (msk). When multiple MPTCP connections are
> present, specific information can be obtained for a given connection
> through the 'mptcp_diag_dump_one' by using the 'token' associated with
> the msk.

(...)

> diff --git a/tools/testing/selftests/net/mptcp/mptcp_diag.c b/tools/testing/selftests/net/mptcp/mptcp_diag.c
> new file mode 100644
> index 000000000000..6dc53ab867c5
> --- /dev/null
> +++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c
> @@ -0,0 +1,271 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2025, Kylin Software */
> +
> +#include <linux/sock_diag.h>
> +#include <linux/rtnetlink.h>
> +#include <linux/inet_diag.h>
> +#include <linux/netlink.h>
> +#include <sys/socket.h>
> +#include <netinet/in.h>
> +#include <linux/tcp.h>
> +
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <stdio.h>
> +
> +#ifndef IPPROTO_MPTCP
> +#define IPPROTO_MPTCP 262
> +#endif
> +
> +struct mptcp_info {
> +	__u8    mptcpi_subflows;
> +	__u8    mptcpi_add_addr_signal;
> +	__u8    mptcpi_add_addr_accepted;
> +	__u8    mptcpi_subflows_max;
> +	__u8    mptcpi_add_addr_signal_max;
> +	__u8    mptcpi_add_addr_accepted_max;
> +	__u32   mptcpi_flags;
> +	__u32   mptcpi_token;
> +	__u64   mptcpi_write_seq;
> +	__u64   mptcpi_snd_una;
> +	__u64   mptcpi_rcv_nxt;
> +	__u8    mptcpi_local_addr_used;
> +	__u8    mptcpi_local_addr_max;
> +	__u8    mptcpi_csum_enabled;
> +	__u32   mptcpi_retransmits;
> +	__u64   mptcpi_bytes_retrans;
> +	__u64   mptcpi_bytes_sent;
> +	__u64   mptcpi_bytes_received;
> +	__u64   mptcpi_bytes_acked;
> +	__u8	mptcpi_subflows_total;
> +	__u8	reserved[3];
> +	__u32	mptcpi_last_data_sent;
> +	__u32	mptcpi_last_data_recv;
> +	__u32	mptcpi_last_ack_recv;

Small detail: some fields are aligned with spaces, others with tabs. Can
you pick only one please? tabs?

(...)

> +static void print_info_msg(struct mptcp_info *info)
> +{
> +	printf("Token & Flags\n");
> +	printf("token:	       %x\n", info->mptcpi_token);
> +	printf("flags:	       %x\n", info->mptcpi_flags);
> +	printf("csum_enabled:  %u\n", info->mptcpi_csum_enabled);
> +
> +	printf("\nBasic Info\n");
> +	printf("subflows:		%u\n", info->mptcpi_subflows);
> +	printf("subflows_max:		%u\n", info->mptcpi_subflows_max);
> +	printf("subflows_total:		%u\n", info->mptcpi_subflows_total);
> +	printf("local_addr_used:	%u\n", info->mptcpi_local_addr_used);
> +	printf("local_addr_max:		%u\n", info->mptcpi_local_addr_max);
> +	printf("add_addr_signal:	%u\n", info->mptcpi_add_addr_signal);
> +	printf("add_addr_accepted:	%u\n", info->mptcpi_add_addr_accepted);
> +	printf("add_addr_signal_max:	%u\n", info->mptcpi_add_addr_signal_max);
> +	printf("add_addr_accepted_max:	%u\n", info->mptcpi_add_addr_accepted_max);
> +
> +	printf("\nTransmission Info\n");
> +	printf("write_seq:	  %llx\n", info->mptcpi_write_seq);
> +	printf("snd_una:	  %llx\n", info->mptcpi_snd_una);
> +	printf("rcv_nxt:	  %llx\n", info->mptcpi_rcv_nxt);
> +	printf("last_data_sent:	  %x\n", info->mptcpi_last_data_sent);
> +	printf("last_data_recv:	  %x\n", info->mptcpi_last_data_recv);
> +	printf("last_ack_recv:	  %x\n", info->mptcpi_last_ack_recv);
> +	printf("retransmits:	  %u\n", info->mptcpi_retransmits);
> +	printf("retransmit bytes: %llu\n", info->mptcpi_bytes_retrans);
> +	printf("bytes_sent:	  %llu\n", info->mptcpi_bytes_sent);
> +	printf("bytes_received:   %llu\n", info->mptcpi_bytes_received);
> +	printf("bytes_acked:	  %llu\n", info->mptcpi_bytes_acked);

Small detail: probably best to do the alignment only with spaces and not
a mix of both because I don't think it would look nice depending on how
the tabs are being printed.

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.