selftests: mptcp: add token for get_addr

The command get_addr() of pm_nl_ctl can be used like this in in-kernel PM:

	pm_nl_ctl get $id

This patch adds token argument for it to support userspace PM:

	pm_nl_ctl get $id token $token

If 'token $token' is passed to get_addr(), copy it into the kernel netlink.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Message-Id: <f7096776872035eab1f1d25a9217a51eb4cffc2f.1708422758.git.tanggeliang@kylinos.cn>

tools/testing/selftests/net/mptcp/pm_nl_ctl.c

@@ -1087,6 +1087,7 @@ int get_addr(int fd, int pm_family, int argc, char *argv[])
 		  1024];
 	struct rtattr *rta, *nest;
 	struct nlmsghdr *nh;
+	u_int32_t token = 0;
 	int nest_start;
 	u_int8_t id;
 	int off = 0;
@@ -1097,10 +1098,12 @@ int get_addr(int fd, int pm_family, int argc, char *argv[])
 			    MPTCP_PM_VER);
 
 	/* the only argument is the address id */
-	if (argc != 3)
+	if (argc != 3 && argc != 5)
 		syntax(argv);
 
 	id = atoi(argv[2]);
+	if (argc == 5 && !strcmp(argv[3], "token"))
+		token = strtoul(argv[4], NULL, 10);
 
 	nest_start = off;
 	nest = (void *)(data + off);
@@ -1116,6 +1119,15 @@ int get_addr(int fd, int pm_family, int argc, char *argv[])
 	off += NLMSG_ALIGN(rta->rta_len);
 	nest->rta_len = off - nest_start;
 
+	/* token */
+	if (token) {
+		rta = (void *)(data + off);
+		rta->rta_type = MPTCP_PM_ATTR_TOKEN;
+		rta->rta_len = RTA_LENGTH(4);
+		memcpy(RTA_DATA(rta), &token, 4);
+		off += NLMSG_ALIGN(rta->rta_len);
+	}
+
 	print_addrs(nh, pm_family, do_nl_req(fd, nh, off, sizeof(data)));
 	return 0;
 }