1 /*
2  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  * 3. The name of David Young may not be used to endorse or promote
13  *    products derived from this software without specific prior
14  *    written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``AS IS'' AND ANY
17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
18  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
19  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL DAVID
20  * YOUNG BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
21  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
22  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
27  * OF SUCH DAMAGE.
28  */
29 
30 /*
31  * Modifications to fit into the linux IEEE 802.11 stack,
32  * Mike Kershaw (dragorn@kismetwireless.net)
33  */
34 
35 #ifndef IEEE80211RADIOTAP_H
36 #define IEEE80211RADIOTAP_H
37 
38 #include <linux/if_ether.h>
39 #include <linux/kernel.h>
40 #include <asm/unaligned.h>
41 
42 /* Base version of the radiotap packet header data */
43 #define PKTHDR_RADIOTAP_VERSION		0
44 
45 /* A generic radio capture format is desirable. There is one for
46  * Linux, but it is neither rigidly defined (there were not even
47  * units given for some fields) nor easily extensible.
48  *
49  * I suggest the following extensible radio capture format. It is
50  * based on a bitmap indicating which fields are present.
51  *
52  * I am trying to describe precisely what the application programmer
53  * should expect in the following, and for that reason I tell the
54  * units and origin of each measurement (where it applies), or else I
55  * use sufficiently weaselly language ("is a monotonically nondecreasing
56  * function of...") that I cannot set false expectations for lawyerly
57  * readers.
58  */
59 
60 /*
61  * The radio capture header precedes the 802.11 header.
62  * All data in the header is little endian on all platforms.
63  */
64 struct ieee80211_radiotap_header {
65 	u8 it_version;		/* Version 0. Only increases
66 				 * for drastic changes,
67 				 * introduction of compatible
68 				 * new fields does not count.
69 				 */
70 	u8 it_pad;
71 	__le16 it_len;		/* length of the whole
72 				 * header in bytes, including
73 				 * it_version, it_pad,
74 				 * it_len, and data fields.
75 				 */
76 	__le32 it_present;	/* A bitmap telling which
77 				 * fields are present. Set bit 31
78 				 * (0x80000000) to extend the
79 				 * bitmap by another 32 bits.
80 				 * Additional extensions are made
81 				 * by setting bit 31.
82 				 */
83 } __packed;
84 
85 /* Name                                 Data type    Units
86  * ----                                 ---------    -----
87  *
88  * IEEE80211_RADIOTAP_TSFT              __le64       microseconds
89  *
90  *      Value in microseconds of the MAC's 64-bit 802.11 Time
91  *      Synchronization Function timer when the first bit of the
92  *      MPDU arrived at the MAC. For received frames, only.
93  *
94  * IEEE80211_RADIOTAP_CHANNEL           2 x __le16   MHz, bitmap
95  *
96  *      Tx/Rx frequency in MHz, followed by flags (see below).
97  *
98  * IEEE80211_RADIOTAP_FHSS              __le16       see below
99  *
100  *      For frequency-hopping radios, the hop set (first byte)
101  *      and pattern (second byte).
102  *
103  * IEEE80211_RADIOTAP_RATE              u8           500kb/s
104  *
105  *      Tx/Rx data rate
106  *
107  * IEEE80211_RADIOTAP_DBM_ANTSIGNAL     s8           decibels from
108  *                                                   one milliwatt (dBm)
109  *
110  *      RF signal power at the antenna, decibel difference from
111  *      one milliwatt.
112  *
113  * IEEE80211_RADIOTAP_DBM_ANTNOISE      s8           decibels from
114  *                                                   one milliwatt (dBm)
115  *
116  *      RF noise power at the antenna, decibel difference from one
117  *      milliwatt.
118  *
119  * IEEE80211_RADIOTAP_DB_ANTSIGNAL      u8           decibel (dB)
120  *
121  *      RF signal power at the antenna, decibel difference from an
122  *      arbitrary, fixed reference.
123  *
124  * IEEE80211_RADIOTAP_DB_ANTNOISE       u8           decibel (dB)
125  *
126  *      RF noise power at the antenna, decibel difference from an
127  *      arbitrary, fixed reference point.
128  *
129  * IEEE80211_RADIOTAP_LOCK_QUALITY      __le16       unitless
130  *
131  *      Quality of Barker code lock. Unitless. Monotonically
132  *      nondecreasing with "better" lock strength. Called "Signal
133  *      Quality" in datasheets.  (Is there a standard way to measure
134  *      this?)
135  *
136  * IEEE80211_RADIOTAP_TX_ATTENUATION    __le16       unitless
137  *
138  *      Transmit power expressed as unitless distance from max
139  *      power set at factory calibration.  0 is max power.
140  *      Monotonically nondecreasing with lower power levels.
141  *
142  * IEEE80211_RADIOTAP_DB_TX_ATTENUATION __le16       decibels (dB)
143  *
144  *      Transmit power expressed as decibel distance from max power
145  *      set at factory calibration.  0 is max power.  Monotonically
146  *      nondecreasing with lower power levels.
147  *
148  * IEEE80211_RADIOTAP_DBM_TX_POWER      s8           decibels from
149  *                                                   one milliwatt (dBm)
150  *
151  *      Transmit power expressed as dBm (decibels from a 1 milliwatt
152  *      reference). This is the absolute power level measured at
153  *      the antenna port.
154  *
155  * IEEE80211_RADIOTAP_FLAGS             u8           bitmap
156  *
157  *      Properties of transmitted and received frames. See flags
158  *      defined below.
159  *
160  * IEEE80211_RADIOTAP_ANTENNA           u8           antenna index
161  *
162  *      Unitless indication of the Rx/Tx antenna for this packet.
163  *      The first antenna is antenna 0.
164  *
165  * IEEE80211_RADIOTAP_RX_FLAGS          __le16       bitmap
166  *
167  *     Properties of received frames. See flags defined below.
168  *
169  * IEEE80211_RADIOTAP_TX_FLAGS          __le16       bitmap
170  *
171  *     Properties of transmitted frames. See flags defined below.
172  *
173  * IEEE80211_RADIOTAP_RTS_RETRIES       u8           data
174  *
175  *     Number of rts retries a transmitted frame used.
176  *
177  * IEEE80211_RADIOTAP_DATA_RETRIES      u8           data
178  *
179  *     Number of unicast retries a transmitted frame used.
180  *
181  * IEEE80211_RADIOTAP_MCS	u8, u8, u8		unitless
182  *
183  *     Contains a bitmap of known fields/flags, the flags, and
184  *     the MCS index.
185  *
186  */
187 enum ieee80211_radiotap_type {
188 	IEEE80211_RADIOTAP_TSFT = 0,
189 	IEEE80211_RADIOTAP_FLAGS = 1,
190 	IEEE80211_RADIOTAP_RATE = 2,
191 	IEEE80211_RADIOTAP_CHANNEL = 3,
192 	IEEE80211_RADIOTAP_FHSS = 4,
193 	IEEE80211_RADIOTAP_DBM_ANTSIGNAL = 5,
194 	IEEE80211_RADIOTAP_DBM_ANTNOISE = 6,
195 	IEEE80211_RADIOTAP_LOCK_QUALITY = 7,
196 	IEEE80211_RADIOTAP_TX_ATTENUATION = 8,
197 	IEEE80211_RADIOTAP_DB_TX_ATTENUATION = 9,
198 	IEEE80211_RADIOTAP_DBM_TX_POWER = 10,
199 	IEEE80211_RADIOTAP_ANTENNA = 11,
200 	IEEE80211_RADIOTAP_DB_ANTSIGNAL = 12,
201 	IEEE80211_RADIOTAP_DB_ANTNOISE = 13,
202 	IEEE80211_RADIOTAP_RX_FLAGS = 14,
203 	IEEE80211_RADIOTAP_TX_FLAGS = 15,
204 	IEEE80211_RADIOTAP_RTS_RETRIES = 16,
205 	IEEE80211_RADIOTAP_DATA_RETRIES = 17,
206 
207 	IEEE80211_RADIOTAP_MCS = 19,
208 
209 	/* valid in every it_present bitmap, even vendor namespaces */
210 	IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE = 29,
211 	IEEE80211_RADIOTAP_VENDOR_NAMESPACE = 30,
212 	IEEE80211_RADIOTAP_EXT = 31
213 };
214 
215 /* Channel flags. */
216 #define	IEEE80211_CHAN_TURBO	0x0010	/* Turbo channel */
217 #define	IEEE80211_CHAN_CCK	0x0020	/* CCK channel */
218 #define	IEEE80211_CHAN_OFDM	0x0040	/* OFDM channel */
219 #define	IEEE80211_CHAN_2GHZ	0x0080	/* 2 GHz spectrum channel. */
220 #define	IEEE80211_CHAN_5GHZ	0x0100	/* 5 GHz spectrum channel */
221 #define	IEEE80211_CHAN_PASSIVE	0x0200	/* Only passive scan allowed */
222 #define	IEEE80211_CHAN_DYN	0x0400	/* Dynamic CCK-OFDM channel */
223 #define	IEEE80211_CHAN_GFSK	0x0800	/* GFSK channel (FHSS PHY) */
224 
225 /* For IEEE80211_RADIOTAP_FLAGS */
226 #define	IEEE80211_RADIOTAP_F_CFP	0x01	/* sent/received
227 						 * during CFP
228 						 */
229 #define	IEEE80211_RADIOTAP_F_SHORTPRE	0x02	/* sent/received
230 						 * with short
231 						 * preamble
232 						 */
233 #define	IEEE80211_RADIOTAP_F_WEP	0x04	/* sent/received
234 						 * with WEP encryption
235 						 */
236 #define	IEEE80211_RADIOTAP_F_FRAG	0x08	/* sent/received
237 						 * with fragmentation
238 						 */
239 #define	IEEE80211_RADIOTAP_F_FCS	0x10	/* frame includes FCS */
240 #define	IEEE80211_RADIOTAP_F_DATAPAD	0x20	/* frame has padding between
241 						 * 802.11 header and payload
242 						 * (to 32-bit boundary)
243 						 */
244 #define IEEE80211_RADIOTAP_F_BADFCS	0x40	/* bad FCS */
245 
246 /* For IEEE80211_RADIOTAP_RX_FLAGS */
247 #define IEEE80211_RADIOTAP_F_RX_BADPLCP	0x0002	/* frame has bad PLCP */
248 
249 /* For IEEE80211_RADIOTAP_TX_FLAGS */
250 #define IEEE80211_RADIOTAP_F_TX_FAIL	0x0001	/* failed due to excessive
251 						 * retries */
252 #define IEEE80211_RADIOTAP_F_TX_CTS	0x0002	/* used cts 'protection' */
253 #define IEEE80211_RADIOTAP_F_TX_RTS	0x0004	/* used rts/cts handshake */
254 
255 
256 /* For IEEE80211_RADIOTAP_MCS */
257 #define IEEE80211_RADIOTAP_MCS_HAVE_BW		0x01
258 #define IEEE80211_RADIOTAP_MCS_HAVE_MCS		0x02
259 #define IEEE80211_RADIOTAP_MCS_HAVE_GI		0x04
260 #define IEEE80211_RADIOTAP_MCS_HAVE_FMT		0x08
261 #define IEEE80211_RADIOTAP_MCS_HAVE_FEC		0x10
262 
263 #define IEEE80211_RADIOTAP_MCS_BW_MASK		0x03
264 #define		IEEE80211_RADIOTAP_MCS_BW_20	0
265 #define		IEEE80211_RADIOTAP_MCS_BW_40	1
266 #define		IEEE80211_RADIOTAP_MCS_BW_20L	2
267 #define		IEEE80211_RADIOTAP_MCS_BW_20U	3
268 #define IEEE80211_RADIOTAP_MCS_SGI		0x04
269 #define IEEE80211_RADIOTAP_MCS_FMT_GF		0x08
270 #define IEEE80211_RADIOTAP_MCS_FEC_LDPC		0x10
271 
272 
273 /* Ugly macro to convert literal channel numbers into their mhz equivalents
274  * There are certianly some conditions that will break this (like feeding it '30')
275  * but they shouldn't arise since nothing talks on channel 30. */
276 #define ieee80211chan2mhz(x) \
277 	(((x) <= 14) ? \
278 	(((x) == 14) ? 2484 : ((x) * 5) + 2407) : \
279 	((x) + 1000) * 5)
280 
281 /* helpers */
ieee80211_get_radiotap_len(unsigned char * data)282 static inline int ieee80211_get_radiotap_len(unsigned char *data)
283 {
284 	struct ieee80211_radiotap_header *hdr =
285 		(struct ieee80211_radiotap_header *)data;
286 
287 	return get_unaligned_le16(&hdr->it_len);
288 }
289 
290 #endif				/* IEEE80211_RADIOTAP_H */
291