For NL80211_FLAG_MLO_VALID_LINK_ID cases, MLD needs to assign link id,
but non-MLD doesn't. Add support of parsing link id where the pattern
is as below. To avoid mess where some fields could have "link-id" as a
value, this pattern is only parsed at the beginning of argv.

	[link-id <LINK ID>]

If found, put NL80211_ATTR_MLO_LINK_ID and remove the assignment from
the argv range.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
---
v3: parse it only at the beginning of argv
v2: newly added
---
 iw.h   |  1 +
 util.c | 31 +++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/iw.h b/iw.h
index 145b058d86ba..df9ea1375dae 100644
--- a/iw.h
+++ b/iw.h
@@ -305,6 +305,7 @@ int set_bitrates(struct nl_msg *msg, int argc, char **argv,
 		 enum nl80211_attrs attr);
 
 int calc_s1g_ch_center_freq(__u8 ch_index, __u8 s1g_oper_class);
+int parse_link_id(struct nl_msg *msg, int *argc, char ***argv);
 
 /* sections */
 DECLARE_SECTION(ap);
diff --git a/util.c b/util.c
index 36c118513e3f..a96fbf968244 100644
--- a/util.c
+++ b/util.c
@@ -2378,3 +2378,34 @@ void print_s1g_capability(const uint8_t *caps)
 	/* Last 2 bits are reserved */
 #undef PRINT_S1G_CAP
 }
+
+int parse_link_id(struct nl_msg *msg, int *argc, char ***argv)
+{
+	unsigned int link_id;
+	char *endptr;
+
+	if (*argc < 1)
+		return 0;
+
+	if (strcmp((*argv)[0], "link-id") != 0)
+		return 0;
+
+	if (*argc == 1)
+		goto usage;
+
+	link_id = strtol((*argv)[1], &endptr, 0);
+	if (*endptr != '\0')
+		goto usage;
+
+	*argv += 2;
+	*argc -= 2;
+
+	NLA_PUT_U8(msg, NL80211_ATTR_MLO_LINK_ID, link_id);
+	return 0;
+
+usage:
+	return HANDLER_RET_USAGE;
+
+nla_put_failure:
+	return -ENOBUFS;
+}
-- 
2.39.0