Series comparison

-[mptcp-next v3 0/2] selftests: mptcp: add tests for increasing
+[mptcp-next v4 0/2] selftests: mptcp: add tests for increasing
 These patches provide a method to verify the 'mptcp_diag_dump_one'
 function, and the new tool 'mptcp_diag' can get the specific mptcp_info
 through multi msks.
+Hi Matt:
+Thank you for your suggestions regarding these patches, they have been
+very useful to me. Sorry for the misunderstanding caused by my misuse of
+the 'CLOSE' keyword. Currently, I have used the 'Link' instead. These
+patches are designed for 'mptcp_dump_one'.
+There may need another test case for 'subflow_get_info_size'. I will
+continue to work on resolving this issue.
+Best wishes!
 Gang Yan (2):
   selftests: mptcp: Add a tool to get specific msk_info
   selftests: mptcp: add a test for mptcp_diag_dump_one
  tools/testing/selftests/net/mptcp/Makefile    |   2 +-
  tools/testing/selftests/net/mptcp/diag.sh     |  27 ++
- .../testing/selftests/net/mptcp/mptcp_diag.c  | 258 ++++++++++++++++++
+ .../testing/selftests/net/mptcp/mptcp_diag.c  | 271 ++++++++++++++++++
-files changed, 286 insertions(+), 1 deletion(-)
+files changed, 299 insertions(+), 1 deletion(-)
  create mode 100644 tools/testing/selftests/net/mptcp/mptcp_diag.c
 --
-.25.1
+.43.0

-[mptcp-next v3 1/2] selftests: mptcp: Add a tool to get specific msk_info
+[mptcp-next v4 1/2] selftests: mptcp: Add a tool to get specific msk_info
 ...
 present, specific information can be obtained for a given connection
 through the 'mptcp_diag_dump_one' by using the 'token' associated with
 the msk.
 Signed-off-by: Gang Yan <yangang@kylinos.cn>
+---
+Notes:
+- v4:
+  - With reference to include/uapi/linux/mptcp.h, the structure members
+    of mptcp_info have been supplemented.
+  - Improve the code style of 'print_info_msg'
+  - With reference to iproute2, make 'parse_nlmsg' compatible with older
+    kernel versions.
+  - Check argc in 'parse_opts' to make sure '-t' is passed.
 ---
  tools/testing/selftests/net/mptcp/Makefile    |   2 +-
- .../testing/selftests/net/mptcp/mptcp_diag.c  | 258 ++++++++++++++++++
+ .../testing/selftests/net/mptcp/mptcp_diag.c  | 271 ++++++++++++++++++
-files changed, 259 insertions(+), 1 deletion(-)
+files changed, 272 insertions(+), 1 deletion(-)
  create mode 100644 tools/testing/selftests/net/mptcp/mptcp_diag.c
 diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile
 index XXXXXXX..XXXXXXX 100644
 --- a/tools/testing/selftests/net/mptcp/Makefile
 ...
 +
 +#ifndef IPPROTO_MPTCP
 +#define IPPROTO_MPTCP 262
 +#endif
 +
-+#ifndef MPTCP_INFO
 +struct mptcp_info {
 +    __u8    mptcpi_subflows;
 +    __u8    mptcpi_add_addr_signal;
 +    __u8    mptcpi_add_addr_accepted;
 +    __u8    mptcpi_subflows_max;
 ...
 +    __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;
 +};
-+
-+#define MPTCP_INFO              1
-+#endif
 +
 +static void die_perror(const char *msg)
 +{
 +    perror(msg);
 +    exit(1);
 ...
 +    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:            %-5u subflows_max:          %u\n",
++    printf("subflows:        %u\n", info->mptcpi_subflows);
-+           info->mptcpi_subflows,
++    printf("subflows_max:        %u\n", info->mptcpi_subflows_max);
-+           info->mptcpi_subflows_max);
++    printf("subflows_total:        %u\n", info->mptcpi_subflows_total);
-+    printf("local_addr_used:     %-5u local_addr_max:        %u\n",
++    printf("local_addr_used:    %u\n", info->mptcpi_local_addr_used);
-+           info->mptcpi_local_addr_used,
++    printf("local_addr_max:        %u\n", info->mptcpi_local_addr_max);
-+           info->mptcpi_local_addr_max);
++    printf("add_addr_signal:    %u\n", info->mptcpi_add_addr_signal);
-+    printf("add_addr_signal:     %-5u add_addr_accepted:     %u\n",
++    printf("add_addr_accepted:    %u\n", info->mptcpi_add_addr_accepted);
-+           info->mptcpi_add_addr_signal,
++    printf("add_addr_signal_max:    %u\n", info->mptcpi_add_addr_signal_max);
-+           info->mptcpi_add_addr_accepted);
++    printf("add_addr_accepted_max:    %u\n", info->mptcpi_add_addr_accepted_max);
 +    printf("add_addr_signal_max: %-5u add_addr_accepted_max: %u\n",
 +           info->mptcpi_add_addr_signal_max,
 +           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);
 +}
 +
 +static void parse_nlmsg(struct nlmsghdr *nlh)
 +{
 +    struct inet_diag_msg *r = NLMSG_DATA(nlh);
 +    struct rtattr *tb[INET_DIAG_MAX + 1];
-+    struct mptcp_info *info;
 +
 +    parse_rtattr_flags(tb, INET_DIAG_MAX, (struct rtattr *)(r + 1),
 +               nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*r)),
 +               NLA_F_NESTED);
 +
 +    if (tb[INET_DIAG_INFO]) {
-+        info = RTA_DATA(tb[INET_DIAG_INFO]);
++        struct mptcp_info *info;
 +        int len;
 +
 +        len = RTA_PAYLOAD(tb[INET_DIAG_INFO]);
 +        /* workaround fort older kernels with less fields */
 +        if (len < sizeof(*info)) {
 +            info = alloca(sizeof(*info));
 +            memcpy(info, RTA_DATA(tb[INET_DIAG_INFO]), len);
 +            memset((char *)info + len, 0, sizeof(*info) - len);
 +        } else
 +            info = RTA_DATA(tb[INET_DIAG_INFO]);
 +        print_info_msg(info);
 +    }
 +}
 +
 +static void recv_nlmsg(int fd, struct nlmsghdr *nlh)
 ...
 +
 +static void parse_opts(int argc, char **argv, __u32 *target_token)
 +{
 +    int c;
 +
++    if (argc < 2)
++        die_usage(1);
++
 +    while ((c = getopt(argc, argv, "ht:")) != -1) {
 +        switch (c) {
 +        case 'h':
 +            die_usage(0);
 +            break;
 ...
 +
 +    return 0;
 +}
 +
 --
-.25.1
+.43.0

-[mptcp-next v3 2/2] selftests: mptcp: add a test for mptcp_diag_dump_one
+[mptcp-next v4 2/2] selftests: mptcp: add a test for mptcp_diag_dump_one
 This patch introduces a new 'chk_diag' test in diag.sh. It retrieves
 the token for a specified MPTCP socket (msk) using the 'ss' command and
 then accesses the 'mptcp_diag_dump_one' in kernel via ./mptcp_diag
 to verify if the correct token is returned.
-Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/524
+Link: https://github.com/multipath-tcp/mptcp_net-next/issues/524
 Signed-off-by: Gang Yan <yangang@kylinos.cn>
+---
+Notes:
+ - v4:
+  - Optimized the check logic for 'ss_token' and 'token′, and before
+    that,first check if 'ss_token' is empty.
 ---
  tools/testing/selftests/net/mptcp/diag.sh | 27 +++++++++++++++++++++++
 file changed, 27 insertions(+)
 diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/selftests/net/mptcp/diag.sh
 ...
 +         awk -F':[ \t]+' '/^token/ {print $2}')"
 +
 +    msg="....chk dump_one"
 +
 +    mptcp_lib_print_title "$msg"
-+    if [ "$ss_token" != "$token" ]; then
++    if [ -n "$ss_token" ] && [ "$ss_token" = "$token" ]; then
 +        mptcp_lib_pr_ok
 +        mptcp_lib_result_pass "${msg}"
 +    else
 +        mptcp_lib_pr_fail "expected $ss_token found $token"
 +        mptcp_lib_result_fail "${msg}"
 +        ret=${KSFT_FAIL}
-+    else
-+        mptcp_lib_pr_ok
-+        mptcp_lib_result_pass "${msg}"
 +    fi
 +}
 +
  msk_info_get_value()
  {
 ...
 +chk_dump_one
  flush_pids
  chk_msk_inuse 0 "2->0"
 --
-.25.1
+.43.0

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.

Signed-off-by: Gang Yan <yangang@kylinos.cn>
---
 tools/testing/selftests/net/mptcp/Makefile    |   2 +-
 .../testing/selftests/net/mptcp/mptcp_diag.c  | 258 ++++++++++++++++++
 2 files changed, 259 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/net/mptcp/mptcp_diag.c

diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile
index XXXXXXX..XXXXXXX 100644
--- a/tools/testing/selftests/net/mptcp/Makefile
+++ b/tools/testing/selftests/net/mptcp/Makefile
@@ -XXX,XX +XXX,XX @@ CFLAGS += -Wall -Wl,--no-as-needed -O2 -g -I$(top_srcdir)/usr/include $(KHDR_INC
 TEST_PROGS := mptcp_connect.sh pm_netlink.sh mptcp_join.sh diag.sh \
 	      simult_flows.sh mptcp_sockopt.sh userspace_pm.sh
 
-TEST_GEN_FILES = mptcp_connect pm_nl_ctl mptcp_sockopt mptcp_inq
+TEST_GEN_FILES = mptcp_connect pm_nl_ctl mptcp_sockopt mptcp_inq mptcp_diag
 
 TEST_FILES := mptcp_lib.sh settings
 
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 XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c
@@ -XXX,XX +XXX,XX @@
+// 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
+
+#ifndef MPTCP_INFO
+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;
+};
+
+#define MPTCP_INFO              1
+#endif
+
+static void die_perror(const char *msg)
+{
+	perror(msg);
+	exit(1);
+}
+
+static void die_usage(int r)
+{
+	fprintf(stderr, "Usage: mptcp_diag -t\n");
+	exit(r);
+}
+
+static void send_query(int fd, __u32 token)
+{
+	struct sockaddr_nl nladdr = {
+		.nl_family = AF_NETLINK
+	};
+	struct {
+		struct nlmsghdr nlh;
+		struct inet_diag_req_v2 r;
+	} req = {
+		.nlh = {
+			.nlmsg_len = sizeof(req),
+			.nlmsg_type = SOCK_DIAG_BY_FAMILY,
+			.nlmsg_flags = NLM_F_REQUEST
+		},
+		.r = {
+			.sdiag_family = AF_INET,
+			.sdiag_protocol = IPPROTO_MPTCP,
+			.id.idiag_cookie[0] = token,
+		}
+	};
+	struct rtattr rta_proto;
+	struct iovec iov[6];
+	int iovlen = 1;
+	__u32 proto;
+
+	req.r.idiag_ext |= (1 << (INET_DIAG_INFO - 1));
+	proto = IPPROTO_MPTCP;
+	rta_proto.rta_type = INET_DIAG_REQ_PROTOCOL;
+	rta_proto.rta_len = RTA_LENGTH(sizeof(proto));
+
+	iov[0] = (struct iovec) {
+		.iov_base = &req,
+		.iov_len = sizeof(req)
+	};
+	iov[iovlen] = (struct iovec){ &rta_proto, sizeof(rta_proto)};
+	iov[iovlen + 1] = (struct iovec){ &proto, sizeof(proto)};
+	req.nlh.nlmsg_len += RTA_LENGTH(sizeof(proto));
+	iovlen += 2;
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = iov,
+		.msg_iovlen = iovlen
+	};
+
+	for (;;) {
+		if (sendmsg(fd, &msg, 0) < 0) {
+			if (errno == EINTR)
+				continue;
+			die_perror("sendmsg");
+		}
+		break;
+	}
+}
+
+static void parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta,
+			       int len, unsigned short flags)
+{
+	unsigned short type;
+
+	memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+	while (RTA_OK(rta, len)) {
+		type = rta->rta_type & ~flags;
+		if (type <= max && !tb[type])
+			tb[type] = rta;
+		rta = RTA_NEXT(rta, len);
+	}
+}
+
+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:            %-5u subflows_max:          %u\n",
+	       info->mptcpi_subflows,
+	       info->mptcpi_subflows_max);
+	printf("local_addr_used:     %-5u local_addr_max:        %u\n",
+	       info->mptcpi_local_addr_used,
+	       info->mptcpi_local_addr_max);
+	printf("add_addr_signal:     %-5u add_addr_accepted:     %u\n",
+	       info->mptcpi_add_addr_signal,
+	       info->mptcpi_add_addr_accepted);
+	printf("add_addr_signal_max: %-5u add_addr_accepted_max: %u\n",
+	       info->mptcpi_add_addr_signal_max,
+	       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("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);
+}
+
+static void parse_nlmsg(struct nlmsghdr *nlh)
+{
+	struct inet_diag_msg *r = NLMSG_DATA(nlh);
+	struct rtattr *tb[INET_DIAG_MAX + 1];
+	struct mptcp_info *info;
+
+	parse_rtattr_flags(tb, INET_DIAG_MAX, (struct rtattr *)(r + 1),
+			   nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*r)),
+			   NLA_F_NESTED);
+
+	if (tb[INET_DIAG_INFO]) {
+		info = RTA_DATA(tb[INET_DIAG_INFO]);
+		print_info_msg(info);
+	}
+}
+
+static void recv_nlmsg(int fd, struct nlmsghdr *nlh)
+{
+	char rcv_buff[8192];
+	struct sockaddr_nl rcv_nladdr = {
+		.nl_family = AF_NETLINK
+	};
+	struct iovec rcv_iov = {
+		.iov_base = rcv_buff,
+		.iov_len = sizeof(rcv_buff)
+	};
+	struct msghdr rcv_msg = {
+		.msg_name = &rcv_nladdr,
+		.msg_namelen = sizeof(rcv_nladdr),
+		.msg_iov = &rcv_iov,
+		.msg_iovlen = 1
+	};
+	int len;
+
+	len = recvmsg(fd, &rcv_msg, 0);
+	nlh = (struct nlmsghdr *)rcv_buff;
+
+	while (NLMSG_OK(nlh, len)) {
+		if (nlh->nlmsg_type == NLMSG_DONE) {
+			printf("NLMSG_DONE\n");
+			break;
+		} else if (nlh->nlmsg_type == NLMSG_ERROR) {
+			struct nlmsgerr *err;
+
+			err = (struct nlmsgerr *)NLMSG_DATA(nlh);
+			printf("Error %d:%s\n",
+			       -(err->error), strerror(-(err->error)));
+			break;
+		}
+		parse_nlmsg(nlh);
+		nlh = NLMSG_NEXT(nlh, len);
+	}
+}
+
+static void get_mptcpinfo(__u32 token)
+{
+	struct nlmsghdr *nlh = NULL;
+	int fd;
+
+	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
+	if (fd < 0)
+		die_perror("Netlink socket");
+
+	send_query(fd, token);
+	recv_nlmsg(fd, nlh);
+
+	close(fd);
+}
+
+static void parse_opts(int argc, char **argv, __u32 *target_token)
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "ht:")) != -1) {
+		switch (c) {
+		case 'h':
+			die_usage(0);
+			break;
+		case 't':
+			sscanf(optarg, "%x", target_token);
+			break;
+		default:
+			die_usage(1);
+			break;
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	__u32 target_token;
+
+	parse_opts(argc, argv, &target_token);
+	get_mptcpinfo(target_token);
+
+	return 0;
+}
+
-- 
2.25.1

This patch introduces a new 'chk_diag' test in diag.sh. It retrieves
the token for a specified MPTCP socket (msk) using the 'ss' command and
then accesses the 'mptcp_diag_dump_one' in kernel via ./mptcp_diag
to verify if the correct token is returned.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/524
Signed-off-by: Gang Yan <yangang@kylinos.cn>
---
 tools/testing/selftests/net/mptcp/diag.sh | 27 +++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/selftests/net/mptcp/diag.sh
index XXXXXXX..XXXXXXX 100755
--- a/tools/testing/selftests/net/mptcp/diag.sh
+++ b/tools/testing/selftests/net/mptcp/diag.sh
@@ -XXX,XX +XXX,XX @@ chk_msk_cestab()
 		 "${expected}" "${msg}" ""
 }
 
+chk_dump_one()
+{
+	local ss_token
+	local token
+	local msg
+
+	ss_token="$(ss -inmHMN $ns | grep 'token:' |\
+		    head -n 1 |\
+		    sed 's/.*token:$[0-9a-f]*$.*/\1/')"
+
+	token="$(ip netns exec $ns ./mptcp_diag -t $ss_token |\
+		 awk -F':[ \t]+' '/^token/ {print $2}')"
+
+	msg="....chk dump_one"
+
+	mptcp_lib_print_title "$msg"
+	if [ "$ss_token" != "$token" ]; then
+		mptcp_lib_pr_fail "expected $ss_token found $token"
+		mptcp_lib_result_fail "${msg}"
+		ret=${KSFT_FAIL}
+	else
+		mptcp_lib_pr_ok
+		mptcp_lib_result_pass "${msg}"
+	fi
+}
+
 msk_info_get_value()
 {
 	local port="${1}"
@@ -XXX,XX +XXX,XX @@ chk_msk_remote_key_nr 2 "....chk remote_key"
 chk_msk_fallback_nr 0 "....chk no fallback"
 chk_msk_inuse 2
 chk_msk_cestab 2
+chk_dump_one
 flush_pids
 
 chk_msk_inuse 0 "2->0"
-- 
2.25.1

Signed-off-by: Gang Yan <yangang@kylinos.cn>

---
Notes:
- v4:
  - With reference to include/uapi/linux/mptcp.h, the structure members
    of mptcp_info have been supplemented.
  - Improve the code style of 'print_info_msg'
  - With reference to iproute2, make 'parse_nlmsg' compatible with older
    kernel versions.
  - Check argc in 'parse_opts' to make sure '-t' is passed.
---
 tools/testing/selftests/net/mptcp/Makefile    |   2 +-
 .../testing/selftests/net/mptcp/mptcp_diag.c  | 271 ++++++++++++++++++
 2 files changed, 272 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/net/mptcp/mptcp_diag.c

diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile
index XXXXXXX..XXXXXXX 100644
--- a/tools/testing/selftests/net/mptcp/Makefile
+++ b/tools/testing/selftests/net/mptcp/Makefile
@@ -XXX,XX +XXX,XX @@ CFLAGS += -Wall -Wl,--no-as-needed -O2 -g -I$(top_srcdir)/usr/include $(KHDR_INC
 TEST_PROGS := mptcp_connect.sh pm_netlink.sh mptcp_join.sh diag.sh \
 	      simult_flows.sh mptcp_sockopt.sh userspace_pm.sh
 
-TEST_GEN_FILES = mptcp_connect pm_nl_ctl mptcp_sockopt mptcp_inq
+TEST_GEN_FILES = mptcp_connect pm_nl_ctl mptcp_sockopt mptcp_inq mptcp_diag
 
 TEST_FILES := mptcp_lib.sh settings
 
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 XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c
@@ -XXX,XX +XXX,XX @@
+// 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;
+};
+
+static void die_perror(const char *msg)
+{
+	perror(msg);
+	exit(1);
+}
+
+static void die_usage(int r)
+{
+	fprintf(stderr, "Usage: mptcp_diag -t\n");
+	exit(r);
+}
+
+static void send_query(int fd, __u32 token)
+{
+	struct sockaddr_nl nladdr = {
+		.nl_family = AF_NETLINK
+	};
+	struct {
+		struct nlmsghdr nlh;
+		struct inet_diag_req_v2 r;
+	} req = {
+		.nlh = {
+			.nlmsg_len = sizeof(req),
+			.nlmsg_type = SOCK_DIAG_BY_FAMILY,
+			.nlmsg_flags = NLM_F_REQUEST
+		},
+		.r = {
+			.sdiag_family = AF_INET,
+			.sdiag_protocol = IPPROTO_MPTCP,
+			.id.idiag_cookie[0] = token,
+		}
+	};
+	struct rtattr rta_proto;
+	struct iovec iov[6];
+	int iovlen = 1;
+	__u32 proto;
+
+	req.r.idiag_ext |= (1 << (INET_DIAG_INFO - 1));
+	proto = IPPROTO_MPTCP;
+	rta_proto.rta_type = INET_DIAG_REQ_PROTOCOL;
+	rta_proto.rta_len = RTA_LENGTH(sizeof(proto));
+
+	iov[0] = (struct iovec) {
+		.iov_base = &req,
+		.iov_len = sizeof(req)
+	};
+	iov[iovlen] = (struct iovec){ &rta_proto, sizeof(rta_proto)};
+	iov[iovlen + 1] = (struct iovec){ &proto, sizeof(proto)};
+	req.nlh.nlmsg_len += RTA_LENGTH(sizeof(proto));
+	iovlen += 2;
+	struct msghdr msg = {
+		.msg_name = &nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = iov,
+		.msg_iovlen = iovlen
+	};
+
+	for (;;) {
+		if (sendmsg(fd, &msg, 0) < 0) {
+			if (errno == EINTR)
+				continue;
+			die_perror("sendmsg");
+		}
+		break;
+	}
+}
+
+static void parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta,
+			       int len, unsigned short flags)
+{
+	unsigned short type;
+
+	memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+	while (RTA_OK(rta, len)) {
+		type = rta->rta_type & ~flags;
+		if (type <= max && !tb[type])
+			tb[type] = rta;
+		rta = RTA_NEXT(rta, len);
+	}
+}
+
+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);
+}
+
+static void parse_nlmsg(struct nlmsghdr *nlh)
+{
+	struct inet_diag_msg *r = NLMSG_DATA(nlh);
+	struct rtattr *tb[INET_DIAG_MAX + 1];
+
+	parse_rtattr_flags(tb, INET_DIAG_MAX, (struct rtattr *)(r + 1),
+			   nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*r)),
+			   NLA_F_NESTED);
+
+	if (tb[INET_DIAG_INFO]) {
+		struct mptcp_info *info;
+		int len;
+
+		len = RTA_PAYLOAD(tb[INET_DIAG_INFO]);
+		/* workaround fort older kernels with less fields */
+		if (len < sizeof(*info)) {
+			info = alloca(sizeof(*info));
+			memcpy(info, RTA_DATA(tb[INET_DIAG_INFO]), len);
+			memset((char *)info + len, 0, sizeof(*info) - len);
+		} else
+			info = RTA_DATA(tb[INET_DIAG_INFO]);
+		print_info_msg(info);
+	}
+}
+
+static void recv_nlmsg(int fd, struct nlmsghdr *nlh)
+{
+	char rcv_buff[8192];
+	struct sockaddr_nl rcv_nladdr = {
+		.nl_family = AF_NETLINK
+	};
+	struct iovec rcv_iov = {
+		.iov_base = rcv_buff,
+		.iov_len = sizeof(rcv_buff)
+	};
+	struct msghdr rcv_msg = {
+		.msg_name = &rcv_nladdr,
+		.msg_namelen = sizeof(rcv_nladdr),
+		.msg_iov = &rcv_iov,
+		.msg_iovlen = 1
+	};
+	int len;
+
+	len = recvmsg(fd, &rcv_msg, 0);
+	nlh = (struct nlmsghdr *)rcv_buff;
+
+	while (NLMSG_OK(nlh, len)) {
+		if (nlh->nlmsg_type == NLMSG_DONE) {
+			printf("NLMSG_DONE\n");
+			break;
+		} else if (nlh->nlmsg_type == NLMSG_ERROR) {
+			struct nlmsgerr *err;
+
+			err = (struct nlmsgerr *)NLMSG_DATA(nlh);
+			printf("Error %d:%s\n",
+			       -(err->error), strerror(-(err->error)));
+			break;
+		}
+		parse_nlmsg(nlh);
+		nlh = NLMSG_NEXT(nlh, len);
+	}
+}
+
+static void get_mptcpinfo(__u32 token)
+{
+	struct nlmsghdr *nlh = NULL;
+	int fd;
+
+	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
+	if (fd < 0)
+		die_perror("Netlink socket");
+
+	send_query(fd, token);
+	recv_nlmsg(fd, nlh);
+
+	close(fd);
+}
+
+static void parse_opts(int argc, char **argv, __u32 *target_token)
+{
+	int c;
+
+	if (argc < 2)
+		die_usage(1);
+
+	while ((c = getopt(argc, argv, "ht:")) != -1) {
+		switch (c) {
+		case 'h':
+			die_usage(0);
+			break;
+		case 't':
+			sscanf(optarg, "%x", target_token);
+			break;
+		default:
+			die_usage(1);
+			break;
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	__u32 target_token;
+
+	parse_opts(argc, argv, &target_token);
+	get_mptcpinfo(target_token);
+
+	return 0;
+}
+
-- 
2.43.0

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/524
Signed-off-by: Gang Yan <yangang@kylinos.cn>

---
Notes:
 - v4:
  - Optimized the check logic for 'ss_token' and 'token′, and before
    that,first check if 'ss_token' is empty.
---
 tools/testing/selftests/net/mptcp/diag.sh | 27 +++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/selftests/net/mptcp/diag.sh
index XXXXXXX..XXXXXXX 100755
--- a/tools/testing/selftests/net/mptcp/diag.sh
+++ b/tools/testing/selftests/net/mptcp/diag.sh
@@ -XXX,XX +XXX,XX @@ chk_msk_cestab()
 		 "${expected}" "${msg}" ""
 }
 
+chk_dump_one()
+{
+	local ss_token
+	local token
+	local msg
+
+	ss_token="$(ss -inmHMN $ns | grep 'token:' |\
+		    head -n 1 |\
+		    sed 's/.*token:$[0-9a-f]*$.*/\1/')"
+
+	token="$(ip netns exec $ns ./mptcp_diag -t $ss_token |\
+		 awk -F':[ \t]+' '/^token/ {print $2}')"
+
+	msg="....chk dump_one"
+
+	mptcp_lib_print_title "$msg"
+	if [ -n "$ss_token" ] && [ "$ss_token" = "$token" ]; then
+		mptcp_lib_pr_ok
+		mptcp_lib_result_pass "${msg}"
+	else
+		mptcp_lib_pr_fail "expected $ss_token found $token"
+		mptcp_lib_result_fail "${msg}"
+		ret=${KSFT_FAIL}
+	fi
+}
+
 msk_info_get_value()
 {
 	local port="${1}"
@@ -XXX,XX +XXX,XX @@ chk_msk_remote_key_nr 2 "....chk remote_key"
 chk_msk_fallback_nr 0 "....chk no fallback"
 chk_msk_inuse 2
 chk_msk_cestab 2
+chk_dump_one
 flush_pids
 
 chk_msk_inuse 0 "2->0"
-- 
2.43.0