iwinfo: export center_chan info for local wifi

Iwinfo already export the htmode but there is no way to know where the
channel expan in case a 40Mhz+ channel width is used. Export the center
channels used by the driver to better know the channel utilizzation of
the wifi.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>

include/iwinfo.h

@@ -282,6 +282,8 @@ struct iwinfo_ops {
 	int (*survey)(const char *, char *, int *);
 	int (*lookup_phy)(const char *, char *);
 	void (*close)(void);
+	int (*center_chan1)(const char *, int *);
+	int (*center_chan2)(const char *, int *);
 };
 
 const char * iwinfo_type(const char *ifname);

iwinfo_cli.c

@@ -445,6 +445,24 @@ static char * print_channel(const struct iwinfo_ops *iw, const char *ifname)
 	return format_channel(ch);
 }
 
+static char * print_center_chan1(const struct iwinfo_ops *iw, const char *ifname)
+{
+	int ch;
+	if (iw->center_chan1(ifname, &ch))
+		ch = -1;
+
+	return format_channel(ch);
+}
+
+static char * print_center_chan2(const struct iwinfo_ops *iw, const char *ifname)
+{
+	int ch;
+	if (iw->center_chan2(ifname, &ch))
+		ch = -1;
+
+	return format_channel(ch);
+}
+
 static char * print_frequency(const struct iwinfo_ops *iw, const char *ifname)
 {
 	int freq;
@@ -566,6 +584,11 @@ static void print_info(const struct iwinfo_ops *iw, const char *ifname)
 		print_mode(iw, ifname),
 		print_channel(iw, ifname),
 		print_frequency(iw, ifname));
+	if (iw->center_chan1 != NULL) {
+		printf("          Center Channel 1: %s",
+			print_center_chan1(iw, ifname));
+		printf(" 2: %s\n", print_center_chan2(iw, ifname));
+	}
 	printf("          Tx-Power: %s  Link Quality: %s/%s\n",
 		print_txpower(iw, ifname),
 		print_quality(iw, ifname),

iwinfo_nl80211.c

@@ -1262,6 +1262,56 @@ static int nl80211_get_frequency(const char *ifname, int *buf)
 	return (*buf == 0) ? -1 : 0;
 }
 
+static int nl80211_get_center_freq1_cb(struct nl_msg *msg, void *arg)
+{
+	int *freq = arg;
+	struct nlattr **tb = nl80211_parse(msg);
+
+	if (tb[NL80211_ATTR_CENTER_FREQ1])
+		*freq = nla_get_u32(tb[NL80211_ATTR_CENTER_FREQ1]);
+
+	return NL_SKIP;
+}
+
+static int nl80211_get_center_freq1(const char *ifname, int *buf)
+{
+	char *res;
+
+	/* try to find frequency from interface info */
+	res = nl80211_phy2ifname(ifname);
+	*buf = 0;
+
+	nl80211_request(res ? res : ifname, NL80211_CMD_GET_INTERFACE, 0,
+	                nl80211_get_center_freq1_cb, buf);
+
+	return (*buf == 0) ? -1 : 0;
+}
+
+static int nl80211_get_center_freq2_cb(struct nl_msg *msg, void *arg)
+{
+	int *freq = arg;
+	struct nlattr **tb = nl80211_parse(msg);
+
+	if (tb[NL80211_ATTR_CENTER_FREQ2])
+		*freq = nla_get_u32(tb[NL80211_ATTR_CENTER_FREQ2]);
+
+	return NL_SKIP;
+}
+
+static int nl80211_get_center_freq2(const char *ifname, int *buf)
+{
+	char *res;
+
+	/* try to find frequency from interface info */
+	res = nl80211_phy2ifname(ifname);
+	*buf = 0;
+
+	nl80211_request(res ? res : ifname, NL80211_CMD_GET_INTERFACE, 0,
+	                nl80211_get_center_freq2_cb, buf);
+
+	return (*buf == 0) ? -1 : 0;
+}
+
 static int nl80211_get_channel(const char *ifname, int *buf)
 {
 	if (!nl80211_get_frequency(ifname, buf))
@@ -1273,6 +1323,28 @@ static int nl80211_get_channel(const char *ifname, int *buf)
 	return -1;
 }
 
+static int nl80211_get_center_chan1(const char *ifname, int *buf)
+{
+	if (!nl80211_get_center_freq1(ifname, buf))
+	{
+		*buf = nl80211_freq2channel(*buf);
+		return 0;
+	}
+
+	return -1;
+}
+
+static int nl80211_get_center_chan2(const char *ifname, int *buf)
+{
+	if (!nl80211_get_center_freq2(ifname, buf))
+	{
+		*buf = nl80211_freq2channel(*buf);
+		return 0;
+	}
+
+	return -1;
+}
+
 static int nl80211_get_txpower_cb(struct nl_msg *msg, void *arg)
 {
 	int *buf = arg;
@@ -3272,5 +3344,7 @@ const struct iwinfo_ops nl80211_ops = {
 	.countrylist      = nl80211_get_countrylist,
 	.survey           = nl80211_get_survey,
 	.lookup_phy       = nl80211_lookup_phyname,
-	.close            = nl80211_close
+	.close            = nl80211_close,
+	.center_chan1     = nl80211_get_center_chan1,
+	.center_chan2     = nl80211_get_center_chan2
 };