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  3. [mptcp-next 0/7] Add 'dump_subflow' test in selftests
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[mptcp-next 5/7] selftests: mptcp: add a helper to get subflow_info

Gang Yan posted 7 patches 8 months ago
There is a newer version of this series
[mptcp-next 5/7] selftests: mptcp: add a helper to get subflow_info
Posted by Gang Yan 8 months ago 
This patch adds 'get_subflow_info' in 'mptcp_diag', which can check whether
a TCP connection is an MPTCP subflow based on the "INET_ULP_INFO_MPTCP"
with tcp_diag method.

Co-developed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Gang Yan <yangang@kylinos.cn>
---
 .../testing/selftests/net/mptcp/mptcp_diag.c  | 68 ++++++++++++++++++-
 1 file changed, 66 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_diag.c b/tools/testing/selftests/net/mptcp/mptcp_diag.c
index 2116b40bc927..03c92940e461 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_diag.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c
@@ -8,6 +8,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <linux/tcp.h>
+#include <arpa/inet.h>
 
 #include <unistd.h>
 #include <stdlib.h>
@@ -19,8 +20,13 @@
 #define IPPROTO_MPTCP 262
 #endif
 
+#define parse_rtattr_nested(tb, max, rta) \
+	(parse_rtattr_flags((tb), (max), RTA_DATA(rta), RTA_PAYLOAD(rta), \
+			    NLA_F_NESTED))
+
 struct params {
 	__u32 target_token;
+	char subflow_addr[1024];
 };
 
 struct mptcp_info {
@@ -58,7 +64,9 @@ static void die_perror(const char *msg)
 
 static void die_usage(int r)
 {
-	fprintf(stderr, "Usage: mptcp_diag -t\n");
+	fprintf(stderr, "Usage:\n"
+			"mptcp_diag -t <token>\n"
+			"mptcp_diag -s \"<saddr> <sport> <daddr> <dport>\"\n");
 	exit(r);
 }
 
@@ -182,6 +190,21 @@ static void parse_nlmsg(struct nlmsghdr *nlh, __u32 proto)
 		}
 		print_info_msg(info);
 	}
+	if (proto == IPPROTO_TCP && tb[INET_DIAG_ULP_INFO]) {
+		struct rtattr *ulpinfo[INET_ULP_INFO_MAX + 1] = { 0 };
+
+		parse_rtattr_nested(ulpinfo, INET_ULP_INFO_MAX,
+				    tb[INET_DIAG_ULP_INFO]);
+
+		if (ulpinfo[INET_ULP_INFO_MPTCP]) {
+			struct rtattr *sfinfo[MPTCP_SUBFLOW_ATTR_MAX + 1] = { 0 };
+
+			parse_rtattr_nested(sfinfo, MPTCP_SUBFLOW_ATTR_MAX,
+					    ulpinfo[INET_ULP_INFO_MPTCP]);
+		} else {
+			printf("It's a normal TCP!\n");
+		}
+	}
 }
 
 static void recv_nlmsg(int fd, __u32 proto)
@@ -244,6 +267,41 @@ static void get_mptcpinfo(__u32 token)
 	close(fd);
 }
 
+static void get_subflow_info(char *subflow_addr)
+{
+	struct inet_diag_req_v2 r = {
+		.sdiag_family           = AF_INET,
+		.sdiag_protocol         = IPPROTO_TCP,
+	};
+	int sport, dport;
+	char saddr[64];	// Take ipv6 into consideration
+	char daddr[64];
+	int ret;
+	int fd;
+
+	ret = sscanf(subflow_addr, "%s %d %s %d", saddr, &sport, daddr, &dport);
+	if (ret != 4)
+		die_perror("IP PORT Pairs has style problems!");
+
+	printf("%s:%d -> %s:%d\n", saddr, sport, daddr, dport);
+
+	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
+	if (fd < 0)
+		die_perror("Netlink socket");
+
+	r.id.idiag_cookie[0] = INET_DIAG_NOCOOKIE;
+	r.id.idiag_cookie[1] = INET_DIAG_NOCOOKIE;
+	r.id.idiag_sport = htons(sport);
+	r.id.idiag_dport = htons(dport);
+	r.id.idiag_if = 0;
+
+	inet_pton(AF_INET, saddr, &r.id.idiag_src);
+	inet_pton(AF_INET, daddr, &r.id.idiag_dst);
+	r.idiag_ext |= (1 << (INET_DIAG_INFO - 1));
+	send_query(fd, &r, IPPROTO_TCP);
+	recv_nlmsg(fd, IPPROTO_TCP);
+}
+
 static void parse_opts(int argc, char **argv, struct params *p)
 {
 	int c;
@@ -251,7 +309,7 @@ static void parse_opts(int argc, char **argv, struct params *p)
 	if (argc < 2)
 		die_usage(1);
 
-	while ((c = getopt(argc, argv, "ht:")) != -1) {
+	while ((c = getopt(argc, argv, "ht:s:")) != -1) {
 		switch (c) {
 		case 'h':
 			die_usage(0);
@@ -259,6 +317,9 @@ static void parse_opts(int argc, char **argv, struct params *p)
 		case 't':
 			sscanf(optarg, "%x", &p->target_token);
 			break;
+		case 's':
+			snprintf(p->subflow_addr, strlen(optarg) + 1, "%s", optarg);
+			break;
 		default:
 			die_usage(1);
 			break;
@@ -275,6 +336,9 @@ int main(int argc, char *argv[])
 	if (p.target_token)
 		get_mptcpinfo(p.target_token);
 
+	if (strlen(p.subflow_addr) != 0)
+		get_subflow_info(p.subflow_addr);
+
 	return 0;
 }
 
-- 
2.25.1
Re: [mptcp-next 5/7] selftests: mptcp: add a helper to get subflow_info
Posted by Geliang Tang 8 months ago 
Hi Gang,

On Wed, 2025-04-16 at 15:35 +0800, Gang Yan wrote:
> This patch adds 'get_subflow_info' in 'mptcp_diag', which can check
> whether
> a TCP connection is an MPTCP subflow based on the
> "INET_ULP_INFO_MPTCP"
> with tcp_diag method.
> 
> Co-developed-by: Geliang Tang <geliang@kernel.org>
> Signed-off-by: Geliang Tang <geliang@kernel.org>
> Signed-off-by: Gang Yan <yangang@kylinos.cn>
> ---
>  .../testing/selftests/net/mptcp/mptcp_diag.c  | 68
> ++++++++++++++++++-
>  1 file changed, 66 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/net/mptcp/mptcp_diag.c
> b/tools/testing/selftests/net/mptcp/mptcp_diag.c
> index 2116b40bc927..03c92940e461 100644
> --- a/tools/testing/selftests/net/mptcp/mptcp_diag.c
> +++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c
> @@ -8,6 +8,7 @@
>  #include <sys/socket.h>
>  #include <netinet/in.h>
>  #include <linux/tcp.h>
> +#include <arpa/inet.h>
>  
>  #include <unistd.h>
>  #include <stdlib.h>
> @@ -19,8 +20,13 @@
>  #define IPPROTO_MPTCP 262
>  #endif
>  
> +#define parse_rtattr_nested(tb, max, rta) \
> +	(parse_rtattr_flags((tb), (max), RTA_DATA(rta),
> RTA_PAYLOAD(rta), \
> +			    NLA_F_NESTED))
> +
>  struct params {
>  	__u32 target_token;
> +	char subflow_addr[1024];
>  };
>  
>  struct mptcp_info {
> @@ -58,7 +64,9 @@ static void die_perror(const char *msg)
>  
>  static void die_usage(int r)
>  {
> -	fprintf(stderr, "Usage: mptcp_diag -t\n");
> +	fprintf(stderr, "Usage:\n"
> +			"mptcp_diag -t <token>\n"
> +			"mptcp_diag -s \"<saddr> <sport> <daddr>
> <dport>\"\n");
>  	exit(r);
>  }
>  
> @@ -182,6 +190,21 @@ static void parse_nlmsg(struct nlmsghdr *nlh,
> __u32 proto)
>  		}
>  		print_info_msg(info);
>  	}
> +	if (proto == IPPROTO_TCP && tb[INET_DIAG_ULP_INFO]) {
> +		struct rtattr *ulpinfo[INET_ULP_INFO_MAX + 1] = { 0
> };
> +
> +		parse_rtattr_nested(ulpinfo, INET_ULP_INFO_MAX,
> +				    tb[INET_DIAG_ULP_INFO]);
> +
> +		if (ulpinfo[INET_ULP_INFO_MPTCP]) {
> +			struct rtattr *sfinfo[MPTCP_SUBFLOW_ATTR_MAX
> + 1] = { 0 };
> +
> +			parse_rtattr_nested(sfinfo,
> MPTCP_SUBFLOW_ATTR_MAX,
> +					   
> ulpinfo[INET_ULP_INFO_MPTCP]);

CI complains this:

selftests - selftests: Commit: 0ce1b7bc31 selftests: mptcp: add a
helper to get subflow_info
  make: Entering directory
'/github/workspace/tools/testing/selftests/net/mptcp'
    CC       mptcp_diag
  mptcp_diag.c: In function 'parse_nlmsg':
  mptcp_diag.c:200:47: error: 'MPTCP_SUBFLOW_ATTR_MAX' undeclared
(first use in this function)
    200 |                         struct rtattr
*sfinfo[MPTCP_SUBFLOW_ATTR_MAX + 1] = { 0 };
        |                                              
^~~~~~~~~~~~~~~~~~~~~~
  mptcp_diag.c:200:47: note: each undeclared identifier is reported
only once for each function it appears in
  mptcp_diag.c:200:40: warning: unused variable 'sfinfo' [-Wunused-
variable]
    200 |                         struct rtattr
*sfinfo[MPTCP_SUBFLOW_ATTR_MAX + 1] = { 0 };
        |                                        ^~~~~~
  make: *** [../../lib.mk:222:
/github/workspace/tools/testing/selftests/net/mptcp/mptcp_diag] Error 1
  make: Leaving directory
'/github/workspace/tools/testing/selftests/net/mptcp'
 
4147cca0b271a635059089415cf51a6072389c1c.1744788247.git.yangang@kylinos.cn
fail Build error with: make -C tools/testing/selftests/net/mptcp
  ERROR: Unable to compile selftests
ERROR: Unable to validate one commit: 0ce1b7bc31 selftests: mptcp: add
a helper to get subflow_info

> +		} else {
> +			printf("It's a normal TCP!\n");
> +		}
> +	}
>  }
>  
>  static void recv_nlmsg(int fd, __u32 proto)
> @@ -244,6 +267,41 @@ static void get_mptcpinfo(__u32 token)
>  	close(fd);
>  }
>  
> +static void get_subflow_info(char *subflow_addr)
> +{
> +	struct inet_diag_req_v2 r = {
> +		.sdiag_family           = AF_INET,
> +		.sdiag_protocol         = IPPROTO_TCP,
> +	};
> +	int sport, dport;
> +	char saddr[64];	// Take ipv6 into consideration
> +	char daddr[64];
> +	int ret;
> +	int fd;
> +
> +	ret = sscanf(subflow_addr, "%s %d %s %d", saddr, &sport,
> daddr, &dport);
> +	if (ret != 4)
> +		die_perror("IP PORT Pairs has style problems!");
> +
> +	printf("%s:%d -> %s:%d\n", saddr, sport, daddr, dport);
> +
> +	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
> +	if (fd < 0)
> +		die_perror("Netlink socket");
> +
> +	r.id.idiag_cookie[0] = INET_DIAG_NOCOOKIE;
> +	r.id.idiag_cookie[1] = INET_DIAG_NOCOOKIE;
> +	r.id.idiag_sport = htons(sport);
> +	r.id.idiag_dport = htons(dport);
> +	r.id.idiag_if = 0;
> +
> +	inet_pton(AF_INET, saddr, &r.id.idiag_src);
> +	inet_pton(AF_INET, daddr, &r.id.idiag_dst);
> +	r.idiag_ext |= (1 << (INET_DIAG_INFO - 1));
> +	send_query(fd, &r, IPPROTO_TCP);
> +	recv_nlmsg(fd, IPPROTO_TCP);
> +}
> +
>  static void parse_opts(int argc, char **argv, struct params *p)
>  {
>  	int c;
> @@ -251,7 +309,7 @@ static void parse_opts(int argc, char **argv,
> struct params *p)
>  	if (argc < 2)
>  		die_usage(1);
>  
> -	while ((c = getopt(argc, argv, "ht:")) != -1) {
> +	while ((c = getopt(argc, argv, "ht:s:")) != -1) {
>  		switch (c) {
>  		case 'h':
>  			die_usage(0);
> @@ -259,6 +317,9 @@ static void parse_opts(int argc, char **argv,
> struct params *p)
>  		case 't':
>  			sscanf(optarg, "%x", &p->target_token);
>  			break;
> +		case 's':
> +			snprintf(p->subflow_addr, strlen(optarg) +
> 1, "%s", optarg);
> +			break;
>  		default:
>  			die_usage(1);
>  			break;
> @@ -275,6 +336,9 @@ int main(int argc, char *argv[])
>  	if (p.target_token)
>  		get_mptcpinfo(p.target_token);
>  
> +	if (strlen(p.subflow_addr) != 0)
> +		get_subflow_info(p.subflow_addr);
> +
>  	return 0;
>  }
>  

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