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Diffstat (limited to 'wsutil/frequency-utils.c')
-rw-r--r-- | wsutil/frequency-utils.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/wsutil/frequency-utils.c b/wsutil/frequency-utils.c new file mode 100644 index 0000000000..2ee6bc9d8c --- /dev/null +++ b/wsutil/frequency-utils.c @@ -0,0 +1,107 @@ +/* frequency-utils.c + * Frequency conversion utility definitions + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 2007 Gerald Combs + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "config.h" + +#include <glib.h> + +#include "frequency-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 */ + +/* From "802.11 Wireless Networks: The Definitive Guide", 2nd Ed. by Matthew Gast */ +static freq_cvt_t freq_cvt[] = { + { 2412, 2472, 1, TRUE }, /* Table 12-1, p 257 */ + { 2484, 2484, 14, TRUE }, /* Table 12-1, p 257 */ + { 5000, 5995, 0, FALSE }, /* Table 13-1, p 289 */ + { 4920, 4995, 240, FALSE } /* Table 13-1, p 289 */ +}; + +#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 + */ +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 g_strdup_printf("%u", freq); + } else { + return g_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: + */ |