nexmon – Blame information for rev 1

Subversion Repositories:
Rev:
Rev Author Line No. Line
1 office 1 /* frequency-utils.c
2 * Frequency conversion utility definitions
3 *
4 * Wireshark - Network traffic analyzer
5 * By Gerald Combs <gerald@wireshark.org>
6 * Copyright 2007 Gerald Combs
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2
11 * of the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21 */
22  
23 #include "config.h"
24  
25 #include <glib.h>
26  
27 #include "frequency-utils.h"
28  
29 typedef struct freq_cvt_s {
30 guint fmin; /* Minimum frequency in MHz */
31 guint fmax; /* Maximum frequency in MHz */
32 gint cmin; /* Minimum/base channel */
33 gboolean is_bg; /* B/G channel? */
34 } freq_cvt_t;
35  
36 #define FREQ_STEP 5 /* MHz. This seems to be consistent, thankfully */
37  
38 /*
39 * From IEEE Std 802.11-2012:
40 *
41 * section 16.4.6.3 "Channel Numbering of operating channels";
42 *
43 * section 17.4.6.3 "Channel Numbering of operating channels";
44 *
45 * section 18.3.8.4.2 "Channel numbering";
46 *
47 * Annex E.
48 *
49 * XXX - Japanese channels 182 through 196 actually have center
50 * frequencies that are off by 2.5 MHz from these values, according
51 * to the IEEE standard, although the table in ARIB STD T-71 version 5.2:
52 *
53 * http://www.arib.or.jp/english/html/overview/doc/1-STD-T71v5_2.pdf
54 *
55 * section 5.3.8.3.3 doesn't show that.
56 *
57 * XXX - what about the U.S. public safety 4.9 GHz band?
58 *
59 * XXX - what about 802.11ad?
60 */
61 static freq_cvt_t freq_cvt[] = {
62 { 2412, 2472, 1, TRUE },
63 { 2484, 2484, 14, TRUE },
64 { 5000, 5995, 0, FALSE },
65 { 4910, 4980, 182, FALSE }
66 };
67  
68 #define NUM_FREQ_CVT (sizeof(freq_cvt) / sizeof(freq_cvt_t))
69 #define MAX_CHANNEL(fc) ( (gint) ((fc.fmax - fc.fmin) / FREQ_STEP) + fc.cmin )
70  
71 /*
72 * Get channel number given a Frequency
73 */
74 gint
75 ieee80211_mhz_to_chan(guint freq) {
76 guint i;
77  
78 for (i = 0; i < NUM_FREQ_CVT; i++) {
79 if (freq >= freq_cvt[i].fmin && freq <= freq_cvt[i].fmax) {
80 return ((freq - freq_cvt[i].fmin) / FREQ_STEP) + freq_cvt[i].cmin;
81 }
82 }
83 return -1;
84 }
85  
86 /*
87 * Get Frequency given a Channel number
88 */
89 guint
90 ieee80211_chan_to_mhz(gint chan, gboolean is_bg) {
91 guint i;
92  
93 for (i = 0; i < NUM_FREQ_CVT; i++) {
94 if (is_bg == freq_cvt[i].is_bg &&
95 chan >= freq_cvt[i].cmin && chan <= MAX_CHANNEL(freq_cvt[i])) {
96 return ((chan - freq_cvt[i].cmin) * FREQ_STEP) + freq_cvt[i].fmin;
97 }
98 }
99 return 0;
100 }
101  
102 /*
103 * Get channel representation string given a Frequency
104 */
105 gchar*
106 ieee80211_mhz_to_str(guint freq){
107 gint chan = ieee80211_mhz_to_chan(freq);
108 gboolean is_bg = FREQ_IS_BG(freq);
109  
110 if (chan < 0) {
111 return g_strdup_printf("%u", freq);
112 } else {
113 return g_strdup_printf("%u [%s %u]", freq, is_bg ? "BG" : "A",
114 chan);
115 }
116 }
117  
118 /*
119 * Editor modelines
120 *
121 * Local Variables:
122 * c-basic-offset: 4
123 * tab-width: 8
124 * indent-tabs-mode: nil
125 * End:
126 *
127 * ex: set shiftwidth=4 tabstop=8 expandtab:
128 * :indentSize=4:tabSize=8:noTabs=true:
129 */