forked from osmocom/wireshark
114 lines
3.3 KiB
C
114 lines
3.3 KiB
C
/* 802_11-utils.c
|
|
* 802.11 utility definitions
|
|
*
|
|
* Wireshark - Network traffic analyzer
|
|
* By Gerald Combs <gerald@wireshark.org>
|
|
* Copyright 2007 Gerald Combs
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0-or-later
|
|
*/
|
|
|
|
#include "config.h"
|
|
#include "802_11-utils.h"
|
|
|
|
typedef struct freq_cvt_s {
|
|
guint fmin; /* Minimum frequency in MHz */
|
|
guint fmax; /* Maximum frequency in MHz */
|
|
gint cmin; /* Minimum/base channel */
|
|
gboolean is_bg; /* B/G channel? */
|
|
} freq_cvt_t;
|
|
|
|
#define FREQ_STEP 5 /* MHz. This seems to be consistent, thankfully */
|
|
|
|
/*
|
|
* XXX - Japanese channels 182 through 196 actually have center
|
|
* frequencies that are off by 2.5 MHz from these values, according
|
|
* to the IEEE standard, although the table in ARIB STD T-71 version 5.2:
|
|
*
|
|
* http://www.arib.or.jp/english/html/overview/doc/1-STD-T71v5_2.pdf
|
|
*
|
|
* section 5.3.8.3.3 doesn't show that.
|
|
*
|
|
* XXX - what about the U.S. public safety 4.9 GHz band?
|
|
*
|
|
* XXX - what about 802.11ad?
|
|
*/
|
|
static freq_cvt_t freq_cvt[] = {
|
|
{ 2412, 2472, 1, TRUE }, /* IEEE Std 802.11-2020: Section 15.4.4.3 and Annex E */
|
|
{ 2484, 2484, 14, TRUE }, /* IEEE Std 802.11-2020: Section 15.4.4.3 and Annex E */
|
|
{ 5000, 5925, 0, FALSE }, /* IEEE Std 802.11-2020: Annex E */
|
|
{ 5950, 7125, 0, FALSE }, /* IEEE Std 802.11ax-2021: Annex E */
|
|
{ 4910, 4980, 182, FALSE },
|
|
};
|
|
|
|
#define NUM_FREQ_CVT (sizeof(freq_cvt) / sizeof(freq_cvt_t))
|
|
#define MAX_CHANNEL(fc) ( (gint) ((fc.fmax - fc.fmin) / FREQ_STEP) + fc.cmin )
|
|
|
|
/*
|
|
* Get channel number given a Frequency
|
|
*/
|
|
gint
|
|
ieee80211_mhz_to_chan(guint freq) {
|
|
guint i;
|
|
|
|
for (i = 0; i < NUM_FREQ_CVT; i++) {
|
|
if (freq >= freq_cvt[i].fmin && freq <= freq_cvt[i].fmax) {
|
|
return ((freq - freq_cvt[i].fmin) / FREQ_STEP) + freq_cvt[i].cmin;
|
|
}
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* Get Frequency given a Channel number
|
|
*
|
|
* XXX - Because channel numbering schemes for 2.4 and 5 overlap with 6 GHz,
|
|
* this function may not return the correct channel. For example, the frequency
|
|
* for channel 1 in 2.4 GHz band is 2412 MHz, while the frequency for channel 1
|
|
* in the 6 GHz band is 5955 MHz. To resolve this problem, this function needs
|
|
* to take a starting frequency to convert channel to frequencies correctly.
|
|
* Unfortunately, this is not possible in some cases, so for now, the order on
|
|
* which frequency ranges are defined will favor 2.4 and 5 GHz over 6 GHz.
|
|
*/
|
|
guint
|
|
ieee80211_chan_to_mhz(gint chan, gboolean is_bg) {
|
|
guint i;
|
|
|
|
for (i = 0; i < NUM_FREQ_CVT; i++) {
|
|
if (is_bg == freq_cvt[i].is_bg &&
|
|
chan >= freq_cvt[i].cmin && chan <= MAX_CHANNEL(freq_cvt[i])) {
|
|
return ((chan - freq_cvt[i].cmin) * FREQ_STEP) + freq_cvt[i].fmin;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Get channel representation string given a Frequency
|
|
*/
|
|
gchar*
|
|
ieee80211_mhz_to_str(guint freq){
|
|
gint chan = ieee80211_mhz_to_chan(freq);
|
|
gboolean is_bg = FREQ_IS_BG(freq);
|
|
|
|
if (chan < 0) {
|
|
return ws_strdup_printf("%u", freq);
|
|
} else {
|
|
return ws_strdup_printf("%u [%s %u]", freq, is_bg ? "BG" : "A",
|
|
chan);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Editor modelines
|
|
*
|
|
* Local Variables:
|
|
* c-basic-offset: 4
|
|
* tab-width: 8
|
|
* indent-tabs-mode: nil
|
|
* End:
|
|
*
|
|
* ex: set shiftwidth=4 tabstop=8 expandtab:
|
|
* :indentSize=4:tabSize=8:noTabs=true:
|
|
*/
|