nl80211: fix frequency/channel conversion for the 6G band

Update using current linux sources, which this was apparently
based on.

Signed-off-by: Andre Heider <a.heider@gmail.com>
[don't fail if no ieee80211ax option is present]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

diff --git a/iwinfo_nl80211.c b/iwinfo_nl80211.c
index 545c56c5322d92317aa0ade3e70740f71608618a..b9dbdbaffd13a053694439b908d99d44b5eae15f 100644 (file)
--- a/iwinfo_nl80211.c
+++ b/iwinfo_nl80211.c
@@ -655,7 +655,13 @@ static int __nl80211_wait(const char *family, const char *group, ...)
 #define nl80211_wait(family, group, ...) \
        __nl80211_wait(family, group, __VA_ARGS__, 0)
 
-
+/* This is linux's ieee80211_freq_khz_to_channel() which is:
+ * SPDX-License-Identifier: GPL-2.0
+ * Copyright 2007-2009 Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2013-2014 Intel Mobile Communications GmbH
+ * Copyright 2017 Intel Deutschland GmbH
+ * Copyright (C) 2018-2022 Intel Corporation
+ */
 static int nl80211_freq2channel(int freq)
 {
        if (freq == 2484)
@@ -664,14 +670,31 @@ static int nl80211_freq2channel(int freq)
                return (freq - 2407) / 5;
        else if (freq >= 4910 && freq <= 4980)
                return (freq - 4000) / 5;
-       else if(freq >= 56160 + 2160 * 1 && freq <= 56160 + 2160 * 6)
+       else if (freq < 5925)
+               return (freq - 5000) / 5;
+       else if (freq == 5935)
+               return 2;
+       else if (freq <= 45000) /* DMG band lower limit */
+               /* see 802.11ax D6.1 27.3.22.2 */
+               return (freq - 5950) / 5;
+       else if (freq >= 58320 && freq <= 70200)
                return (freq - 56160) / 2160;
        else
-               return (freq - 5000) / 5;
+               return 0;
 }
 
-static int nl80211_channel2freq(int channel, const char *band)
+/* This is linux's ieee80211_channel_to_freq_khz() which is:
+ * SPDX-License-Identifier: GPL-2.0
+ * Copyright 2007-2009 Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2013-2014 Intel Mobile Communications GmbH
+ * Copyright 2017 Intel Deutschland GmbH
+ * Copyright (C) 2018-2022 Intel Corporation
+ */
+static int nl80211_channel2freq(int channel, const char *band, bool ax)
 {
+       if (channel < 1)
+               return 0;
+
        if (!band || band[0] != 'a')
        {
                if (channel == 14)
@@ -679,9 +702,17 @@ static int nl80211_channel2freq(int channel, const char *band)
                else if (channel < 14)
                        return (channel * 5) + 2407;
        }
-       else if ( strcmp(band, "ad") == 0)
+       else if (strcmp(band, "ad")  == 0)
+       {
+               if (channel < 7)
+                       return 56160 + 2160 * channel;
+       }
+       else if (ax)
        {
-               return 56160 + 2160 * channel;
+               if (channel == 2)
+                       return 5935;
+               if (channel < 233)
+                       return (channel * 5) + 5950;
        }
        else
        {
@@ -1336,7 +1367,7 @@ static int nl80211_get_frequency_info_cb(struct nl_msg *msg, void *arg)
 
 static int nl80211_get_frequency(const char *ifname, int *buf)
 {
-       char *res, channel[4], hwmode[3];
+       char *res, channel[4] = { 0 }, hwmode[3] = { 0 }, ax[2] = { 0 };
 
        /* try to find frequency from interface info */
        res = nl80211_phy2ifname(ifname);
@@ -1348,9 +1379,10 @@ static int nl80211_get_frequency(const char *ifname, int *buf)
        /* failed, try to find frequency from hostapd info */
        if ((*buf == 0) &&
            nl80211_hostapd_query(ifname, "hw_mode", hwmode, sizeof(hwmode),
-                                         "channel", channel, sizeof(channel)) == 2)
+                                         "channel", channel, sizeof(channel),
+                                         "ieee80211ax", ax, sizeof(ax)) >= 2)
        {
-               *buf = nl80211_channel2freq(atoi(channel), hwmode);
+               *buf = nl80211_channel2freq(atoi(channel), hwmode, ax[0] == '1');
        }
 
        /* failed, try to find frequency from scan results */