[mptcp-next,v2,1/2] selftests: mptcp: Add a tool to get specific msk_info

Commit Message

Gang Yan Feb. 20, 2025, 7:11 a.m. UTC

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 <[e-mail]>
---
 tools/testing/selftests/net/mptcp/Makefile    |   2 +-
 .../testing/selftests/net/mptcp/mptcp_diag.c  | 235 ++++++++++++++++++
 2 files changed, 236 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/net/mptcp/mptcp_diag.c

Comments

Matthieu Baerts Feb. 20, 2025, 11:22 a.m. UTC | #1

Hi Gang Yan,

On 20/02/2025 08:11, 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.

Thank you for the v2. I had a very quick look, mainly because I saw
CheckPatch and Shellcheck were complaining about this series.

Do you mind looking at that please?

https://github.com/multipath-tcp/mptcp_net-next/actions/runs/13430040104

> 
> Signed-off-by: Gang Yan <[e-mail]>
> ---
>  tools/testing/selftests/net/mptcp/Makefile    |   2 +-
>  .../testing/selftests/net/mptcp/mptcp_diag.c  | 235 ++++++++++++++++++
>  2 files changed, 236 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 c76525fe2b84..340e1a777e16 100644
> --- a/tools/testing/selftests/net/mptcp/Makefile
> +++ b/tools/testing/selftests/net/mptcp/Makefile
> @@ -7,7 +7,7 @@ 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 000000000000..3e0be9e58912
> --- /dev/null
> +++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c
> @@ -0,0 +1,235 @@
> +// 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)

(the indentation doesn't look OK)

> +{
> +	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 struct mptcp_info *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]);
> +		return info;

The cope of "info" is local if it is a pointer from 'tb' that as been
allocated on the stack. A pointer to this local structure should then
not be returned.

Either allocate memory on heap, or probably better: a pointer to an
mptcp_info structure should be passed to get_mptcpinfo() -> recv_nlmsg()
-> parse_nlmsg(). Or use a global variable. So here, we would fill this
space, and read it later on.

(Or, if you only need the token, only return that, but that's strange to
give the token, and only get the token in return...)

(Or: don't return anything here, but simply print each field of the
mptcp_info structure → but that sounds better to do that after having
called get_mptcpinfo().)

> +	}
> +
> +	die_perror("Has no INET_DIAG_INFO");
> +	return info;

"info" might not have been assigned.

> +}
> +
> +static struct mptcp_info *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
> +	};
> +	struct mptcp_info *info = NULL;
> +	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;
> +		}
> +		info = parse_nlmsg(nlh);
> +		nlh = NLMSG_NEXT(nlh, len);
> +	}
> +	close(fd);

That's strange to close the fd here. Probably best to do that in
get_mptcpinfo() where it has been opened.

> +	return info;
> +}
> +
> +static struct mptcp_info *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);
> +	return recv_nlmsg(fd, nlh);
> +}
> +
> +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(1);

exit(0) for -h.

> +			break;
> +		case 't':
> +			sscanf(optarg, "%x", target_token);
> +			break;
> +		default:
> +			die_usage(1);
> +			break;
> +		}
> +	}

It might be good to call "die_usage(1)" if the program has not been
called with '-t'.

> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	struct mptcp_info *info = NULL;
> +	__u32 target_token;
> +
> +	parse_opts(argc, argv, &target_token);
> +	info = get_mptcpinfo(target_token);
> +
> +	if (info)
> +		printf("token:%x\n", info->mptcpi_token);
> +	else
> +		perror("No Such msk using this token!\n");
> +
> +	return 0;
> +}
> +

Cheers,
Matt

Patch

diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile
index c76525fe2b84..340e1a777e16 100644
--- a/tools/testing/selftests/net/mptcp/Makefile
+++ b/tools/testing/selftests/net/mptcp/Makefile
@@ -7,7 +7,7 @@  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 000000000000..3e0be9e58912
--- /dev/null
+++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c
@@ -0,0 +1,235 @@ 
+// 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 struct mptcp_info *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]);
+		return info;
+	}
+
+	die_perror("Has no INET_DIAG_INFO");
+	return info;
+}
+
+static struct mptcp_info *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
+	};
+	struct mptcp_info *info = NULL;
+	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;
+		}
+		info = parse_nlmsg(nlh);
+		nlh = NLMSG_NEXT(nlh, len);
+	}
+	close(fd);
+	return info;
+}
+
+static struct mptcp_info *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);
+	return recv_nlmsg(fd, nlh);
+}
+
+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(1);
+			break;
+		case 't':
+			sscanf(optarg, "%x", target_token);
+			break;
+		default:
+			die_usage(1);
+			break;
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	struct mptcp_info *info = NULL;
+	__u32 target_token;
+
+	parse_opts(argc, argv, &target_token);
+	info = get_mptcpinfo(target_token);
+
+	if (info)
+		printf("token:%x\n", info->mptcpi_token);
+	else
+		perror("No Such msk using this token!\n");
+
+	return 0;
+}
+