1 /* $FreeBSD: src/sys/net80211/ieee80211_radiotap.h,v 1.5 2005/01/22 20:12:05 sam Exp $ */
2 /* $NetBSD: ieee80211_radiotap.h,v 1.11 2005/06/22 06:16:02 dyoung Exp $ */
3 
4 /*-
5  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of David Young may not be used to endorse or promote
16  *    products derived from this software without specific prior
17  *    written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``AS IS'' AND ANY
20  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
22  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL DAVID
23  * YOUNG BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
25  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30  * OF SUCH DAMAGE.
31  */
32 
33 /*
34  * Modifications to fit into the linux IEEE 802.11 stack,
35  * Mike Kershaw (dragorn@kismetwireless.net)
36  */
37 
38 #ifndef IEEE80211RADIOTAP_H
39 #define IEEE80211RADIOTAP_H
40 
41 #include <linux/if_ether.h>
42 #include <linux/kernel.h>
43 #include <asm/unaligned.h>
44 
45 /* Radiotap header version (from official NetBSD feed) */
46 #define IEEE80211RADIOTAP_VERSION	"1.5"
47 /* Base version of the radiotap packet header data */
48 #define PKTHDR_RADIOTAP_VERSION		0
49 
50 /* A generic radio capture format is desirable. There is one for
51  * Linux, but it is neither rigidly defined (there were not even
52  * units given for some fields) nor easily extensible.
53  *
54  * I suggest the following extensible radio capture format. It is
55  * based on a bitmap indicating which fields are present.
56  *
57  * I am trying to describe precisely what the application programmer
58  * should expect in the following, and for that reason I tell the
59  * units and origin of each measurement (where it applies), or else I
60  * use sufficiently weaselly language ("is a monotonically nondecreasing
61  * function of...") that I cannot set false expectations for lawyerly
62  * readers.
63  */
64 
65 /* XXX tcpdump/libpcap do not tolerate variable-length headers,
66  * yet, so we pad every radiotap header to 64 bytes. Ugh.
67  */
68 #define IEEE80211_RADIOTAP_HDRLEN	64
69 
70 /* The radio capture header precedes the 802.11 header.
71  * All data in the header is little endian on all platforms.
72  */
73 struct ieee80211_radiotap_header {
74 	u8 it_version;		/* Version 0. Only increases
75 				 * for drastic changes,
76 				 * introduction of compatible
77 				 * new fields does not count.
78 				 */
79 	u8 it_pad;
80 	__le16 it_len;		/* length of the whole
81 				 * header in bytes, including
82 				 * it_version, it_pad,
83 				 * it_len, and data fields.
84 				 */
85 	__le32 it_present;	/* A bitmap telling which
86 				 * fields are present. Set bit 31
87 				 * (0x80000000) to extend the
88 				 * bitmap by another 32 bits.
89 				 * Additional extensions are made
90 				 * by setting bit 31.
91 				 */
92 };
93 
94 /* Name                                 Data type    Units
95  * ----                                 ---------    -----
96  *
97  * IEEE80211_RADIOTAP_TSFT              __le64       microseconds
98  *
99  *      Value in microseconds of the MAC's 64-bit 802.11 Time
100  *      Synchronization Function timer when the first bit of the
101  *      MPDU arrived at the MAC. For received frames, only.
102  *
103  * IEEE80211_RADIOTAP_CHANNEL           2 x __le16   MHz, bitmap
104  *
105  *      Tx/Rx frequency in MHz, followed by flags (see below).
106  *
107  * IEEE80211_RADIOTAP_FHSS              __le16       see below
108  *
109  *      For frequency-hopping radios, the hop set (first byte)
110  *      and pattern (second byte).
111  *
112  * IEEE80211_RADIOTAP_RATE              u8           500kb/s
113  *
114  *      Tx/Rx data rate
115  *
116  * IEEE80211_RADIOTAP_DBM_ANTSIGNAL     s8           decibels from
117  *                                                   one milliwatt (dBm)
118  *
119  *      RF signal power at the antenna, decibel difference from
120  *      one milliwatt.
121  *
122  * IEEE80211_RADIOTAP_DBM_ANTNOISE      s8           decibels from
123  *                                                   one milliwatt (dBm)
124  *
125  *      RF noise power at the antenna, decibel difference from one
126  *      milliwatt.
127  *
128  * IEEE80211_RADIOTAP_DB_ANTSIGNAL      u8           decibel (dB)
129  *
130  *      RF signal power at the antenna, decibel difference from an
131  *      arbitrary, fixed reference.
132  *
133  * IEEE80211_RADIOTAP_DB_ANTNOISE       u8           decibel (dB)
134  *
135  *      RF noise power at the antenna, decibel difference from an
136  *      arbitrary, fixed reference point.
137  *
138  * IEEE80211_RADIOTAP_LOCK_QUALITY      __le16       unitless
139  *
140  *      Quality of Barker code lock. Unitless. Monotonically
141  *      nondecreasing with "better" lock strength. Called "Signal
142  *      Quality" in datasheets.  (Is there a standard way to measure
143  *      this?)
144  *
145  * IEEE80211_RADIOTAP_TX_ATTENUATION    __le16       unitless
146  *
147  *      Transmit power expressed as unitless distance from max
148  *      power set at factory calibration.  0 is max power.
149  *      Monotonically nondecreasing with lower power levels.
150  *
151  * IEEE80211_RADIOTAP_DB_TX_ATTENUATION __le16       decibels (dB)
152  *
153  *      Transmit power expressed as decibel distance from max power
154  *      set at factory calibration.  0 is max power.  Monotonically
155  *      nondecreasing with lower power levels.
156  *
157  * IEEE80211_RADIOTAP_DBM_TX_POWER      s8           decibels from
158  *                                                   one milliwatt (dBm)
159  *
160  *      Transmit power expressed as dBm (decibels from a 1 milliwatt
161  *      reference). This is the absolute power level measured at
162  *      the antenna port.
163  *
164  * IEEE80211_RADIOTAP_FLAGS             u8           bitmap
165  *
166  *      Properties of transmitted and received frames. See flags
167  *      defined below.
168  *
169  * IEEE80211_RADIOTAP_ANTENNA           u8           antenna index
170  *
171  *      Unitless indication of the Rx/Tx antenna for this packet.
172  *      The first antenna is antenna 0.
173  *
174  * IEEE80211_RADIOTAP_RX_FLAGS          __le16       bitmap
175  *
176  *     Properties of received frames. See flags defined below.
177  *
178  * IEEE80211_RADIOTAP_TX_FLAGS          __le16       bitmap
179  *
180  *     Properties of transmitted frames. See flags defined below.
181  *
182  * IEEE80211_RADIOTAP_RTS_RETRIES       u8           data
183  *
184  *     Number of rts retries a transmitted frame used.
185  *
186  * IEEE80211_RADIOTAP_DATA_RETRIES      u8           data
187  *
188  *     Number of unicast retries a transmitted frame used.
189  *
190  */
191 enum ieee80211_radiotap_type {
192 	IEEE80211_RADIOTAP_TSFT = 0,
193 	IEEE80211_RADIOTAP_FLAGS = 1,
194 	IEEE80211_RADIOTAP_RATE = 2,
195 	IEEE80211_RADIOTAP_CHANNEL = 3,
196 	IEEE80211_RADIOTAP_FHSS = 4,
197 	IEEE80211_RADIOTAP_DBM_ANTSIGNAL = 5,
198 	IEEE80211_RADIOTAP_DBM_ANTNOISE = 6,
199 	IEEE80211_RADIOTAP_LOCK_QUALITY = 7,
200 	IEEE80211_RADIOTAP_TX_ATTENUATION = 8,
201 	IEEE80211_RADIOTAP_DB_TX_ATTENUATION = 9,
202 	IEEE80211_RADIOTAP_DBM_TX_POWER = 10,
203 	IEEE80211_RADIOTAP_ANTENNA = 11,
204 	IEEE80211_RADIOTAP_DB_ANTSIGNAL = 12,
205 	IEEE80211_RADIOTAP_DB_ANTNOISE = 13,
206 	IEEE80211_RADIOTAP_RX_FLAGS = 14,
207 	IEEE80211_RADIOTAP_TX_FLAGS = 15,
208 	IEEE80211_RADIOTAP_RTS_RETRIES = 16,
209 	IEEE80211_RADIOTAP_DATA_RETRIES = 17,
210 	IEEE80211_RADIOTAP_EXT = 31
211 };
212 
213 /* Channel flags. */
214 #define	IEEE80211_CHAN_TURBO	0x0010	/* Turbo channel */
215 #define	IEEE80211_CHAN_CCK	0x0020	/* CCK channel */
216 #define	IEEE80211_CHAN_OFDM	0x0040	/* OFDM channel */
217 #define	IEEE80211_CHAN_2GHZ	0x0080	/* 2 GHz spectrum channel. */
218 #define	IEEE80211_CHAN_5GHZ	0x0100	/* 5 GHz spectrum channel */
219 #define	IEEE80211_CHAN_PASSIVE	0x0200	/* Only passive scan allowed */
220 #define	IEEE80211_CHAN_DYN	0x0400	/* Dynamic CCK-OFDM channel */
221 #define	IEEE80211_CHAN_GFSK	0x0800	/* GFSK channel (FHSS PHY) */
222 
223 /* For IEEE80211_RADIOTAP_FLAGS */
224 #define	IEEE80211_RADIOTAP_F_CFP	0x01	/* sent/received
225 						 * during CFP
226 						 */
227 #define	IEEE80211_RADIOTAP_F_SHORTPRE	0x02	/* sent/received
228 						 * with short
229 						 * preamble
230 						 */
231 #define	IEEE80211_RADIOTAP_F_WEP	0x04	/* sent/received
232 						 * with WEP encryption
233 						 */
234 #define	IEEE80211_RADIOTAP_F_FRAG	0x08	/* sent/received
235 						 * with fragmentation
236 						 */
237 #define	IEEE80211_RADIOTAP_F_FCS	0x10	/* frame includes FCS */
238 #define	IEEE80211_RADIOTAP_F_DATAPAD	0x20	/* frame has padding between
239 						 * 802.11 header and payload
240 						 * (to 32-bit boundary)
241 						 */
242 /* For IEEE80211_RADIOTAP_RX_FLAGS */
243 #define IEEE80211_RADIOTAP_F_RX_BADFCS	0x0001	/* frame failed crc check */
244 
245 /* For IEEE80211_RADIOTAP_TX_FLAGS */
246 #define IEEE80211_RADIOTAP_F_TX_FAIL	0x0001	/* failed due to excessive
247 						 * retries */
248 #define IEEE80211_RADIOTAP_F_TX_CTS	0x0002	/* used cts 'protection' */
249 #define IEEE80211_RADIOTAP_F_TX_RTS	0x0004	/* used rts/cts handshake */
250 
251 /* Ugly macro to convert literal channel numbers into their mhz equivalents
252  * There are certianly some conditions that will break this (like feeding it '30')
253  * but they shouldn't arise since nothing talks on channel 30. */
254 #define ieee80211chan2mhz(x) \
255 	(((x) <= 14) ? \
256 	(((x) == 14) ? 2484 : ((x) * 5) + 2407) : \
257 	((x) + 1000) * 5)
258 
259 /* helpers */
260 static inline int ieee80211_get_radiotap_len(unsigned char *data)
261 {
262 	struct ieee80211_radiotap_header *hdr =
263 		(struct ieee80211_radiotap_header *)data;
264 
265 	return get_unaligned_le16(&hdr->it_len);
266 }
267 
268 #endif				/* IEEE80211_RADIOTAP_H */
269