1 /*-
2 * Copyright (c) 2009 Sam Leffler, Errno Consulting
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28
29 /*
30 * IEEE 802.11 radiotap support.
31 */
32 #include "opt_wlan.h"
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/mbuf.h>
37 #include <sys/malloc.h>
38 #include <sys/endian.h>
39 #include <sys/kernel.h>
40
41 #include <sys/socket.h>
42
43 #include <net/bpf.h>
44 #include <net/if.h>
45 #include <net/if_llc.h>
46 #include <net/if_media.h>
47
48 #include <net80211/ieee80211_var.h>
49
50 static int radiotap_offset(struct ieee80211_radiotap_header *, int, int);
51
52 void
53 ieee80211_radiotap_attach(struct ieee80211com *ic,
54 struct ieee80211_radiotap_header *th, int tlen, uint32_t tx_radiotap,
55 struct ieee80211_radiotap_header *rh, int rlen, uint32_t rx_radiotap)
56 {
57 ieee80211_radiotap_attachv(ic, th, tlen, 0, tx_radiotap,
58 rh, rlen, 0, rx_radiotap);
59 }
60
61 void
62 ieee80211_radiotap_attachv(struct ieee80211com *ic,
63 struct ieee80211_radiotap_header *th,
64 int tlen, int n_tx_v, uint32_t tx_radiotap,
65 struct ieee80211_radiotap_header *rh,
66 int rlen, int n_rx_v, uint32_t rx_radiotap)
67 {
68 #define B(_v) (1<<(_v))
69 int off;
70
71 th->it_len = htole16(roundup2(tlen, sizeof(uint32_t)));
72 th->it_present = htole32(tx_radiotap);
73 ic->ic_th = th;
74 /* calculate offset to channel data */
75 off = -1;
76 if (tx_radiotap & B(IEEE80211_RADIOTAP_CHANNEL))
77 off = radiotap_offset(th, n_tx_v, IEEE80211_RADIOTAP_CHANNEL);
78 else if (tx_radiotap & B(IEEE80211_RADIOTAP_XCHANNEL))
79 off = radiotap_offset(th, n_tx_v, IEEE80211_RADIOTAP_XCHANNEL);
80 if (off == -1) {
81 if_printf(ic->ic_ifp, "%s: no tx channel, radiotap 0x%x\n",
82 __func__, tx_radiotap);
83 /* NB: we handle this case but data will have no chan spec */
84 } else
85 ic->ic_txchan = ((uint8_t *) th) + off;
86
87 rh->it_len = htole16(roundup2(rlen, sizeof(uint32_t)));
88 rh->it_present = htole32(rx_radiotap);
89 ic->ic_rh = rh;
90 /* calculate offset to channel data */
91 off = -1;
92 if (rx_radiotap & B(IEEE80211_RADIOTAP_CHANNEL))
93 off = radiotap_offset(rh, n_rx_v, IEEE80211_RADIOTAP_CHANNEL);
94 else if (rx_radiotap & B(IEEE80211_RADIOTAP_XCHANNEL))
95 off = radiotap_offset(rh, n_rx_v, IEEE80211_RADIOTAP_XCHANNEL);
96 if (off == -1) {
97 if_printf(ic->ic_ifp, "%s: no rx channel, radiotap 0x%x\n",
98 __func__, rx_radiotap);
99 /* NB: we handle this case but data will have no chan spec */
100 } else
101 ic->ic_rxchan = ((uint8_t *) rh) + off;
102 #undef B
103 }
104
105 void
106 ieee80211_radiotap_detach(struct ieee80211com *ic)
107 {
108 }
109
110 void
111 ieee80211_radiotap_vattach(struct ieee80211vap *vap)
112 {
113 struct ieee80211com *ic = vap->iv_ic;
114 struct ieee80211_radiotap_header *th = ic->ic_th;
115
116 if (th != NULL && ic->ic_rh != NULL) {
117 /* radiotap DLT for raw 802.11 frames */
118 bpfattach2(vap->iv_ifp, DLT_IEEE802_11_RADIO,
119 sizeof(struct ieee80211_frame) + le16toh(th->it_len),
120 &vap->iv_rawbpf);
121 }
122 }
123
124 void
125 ieee80211_radiotap_vdetach(struct ieee80211vap *vap)
126 {
127 /* NB: bpfattach is called by ether_ifdetach and claims all taps */
128 }
129
130 static void
131 set_channel(void *p, const struct ieee80211_channel *c)
132 {
133 struct {
134 uint16_t freq;
135 uint16_t flags;
136 } *rc = p;
137
138 rc->freq = htole16(c->ic_freq);
139 rc->flags = htole16(c->ic_flags);
140 }
141
142 static void
143 set_xchannel(void *p, const struct ieee80211_channel *c)
144 {
145 struct {
146 uint32_t flags;
147 uint16_t freq;
148 uint8_t ieee;
149 uint8_t maxpow;
150 } *rc = p;
151
152 rc->flags = htole32(c->ic_flags);
153 rc->freq = htole16(c->ic_freq);
154 rc->ieee = c->ic_ieee;
155 rc->maxpow = c->ic_maxregpower;
156 }
157
158 /*
159 * Update radiotap state on channel change.
160 */
161 void
162 ieee80211_radiotap_chan_change(struct ieee80211com *ic)
163 {
164 if (ic->ic_rxchan != NULL) {
165 struct ieee80211_radiotap_header *rh = ic->ic_rh;
166
167 if (rh->it_present & htole32(1<<IEEE80211_RADIOTAP_XCHANNEL))
168 set_xchannel(ic->ic_rxchan, ic->ic_curchan);
169 else if (rh->it_present & htole32(1<<IEEE80211_RADIOTAP_CHANNEL))
170 set_channel(ic->ic_rxchan, ic->ic_curchan);
171 }
172 if (ic->ic_txchan != NULL) {
173 struct ieee80211_radiotap_header *th = ic->ic_th;
174
175 if (th->it_present & htole32(1<<IEEE80211_RADIOTAP_XCHANNEL))
176 set_xchannel(ic->ic_txchan, ic->ic_curchan);
177 else if (th->it_present & htole32(1<<IEEE80211_RADIOTAP_CHANNEL))
178 set_channel(ic->ic_txchan, ic->ic_curchan);
179 }
180 }
181
182 /*
183 * Distribute radiotap data (+packet) to all monitor mode
184 * vaps with an active tap other than vap0.
185 */
186 static void
187 spam_vaps(struct ieee80211vap *vap0, struct mbuf *m,
188 struct ieee80211_radiotap_header *rh, int len)
189 {
190 struct ieee80211com *ic = vap0->iv_ic;
191 struct ieee80211vap *vap;
192
193 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
194 if (vap != vap0 &&
195 vap->iv_opmode == IEEE80211_M_MONITOR &&
196 (vap->iv_flags_ext & IEEE80211_FEXT_BPF) &&
197 vap->iv_state != IEEE80211_S_INIT)
198 bpf_mtap2(vap->iv_rawbpf, rh, len, m);
199 }
200 }
201
202 /*
203 * Dispatch radiotap data for transmitted packet.
204 */
205 void
206 ieee80211_radiotap_tx(struct ieee80211vap *vap0, struct mbuf *m)
207 {
208 struct ieee80211com *ic = vap0->iv_ic;
209 struct ieee80211_radiotap_header *th = ic->ic_th;
210 int len;
211
212 KASSERT(th != NULL, ("no tx radiotap header"));
213 len = le16toh(th->it_len);
214
215 if (vap0->iv_flags_ext & IEEE80211_FEXT_BPF)
216 bpf_mtap2(vap0->iv_rawbpf, th, len, m);
217 /*
218 * Spam monitor mode vaps.
219 */
220 if (ic->ic_montaps != 0)
221 spam_vaps(vap0, m, th, len);
222 }
223
224 /*
225 * Dispatch radiotap data for received packet.
226 */
227 void
228 ieee80211_radiotap_rx(struct ieee80211vap *vap0, struct mbuf *m)
229 {
230 struct ieee80211com *ic = vap0->iv_ic;
231 struct ieee80211_radiotap_header *rh = ic->ic_rh;
232 int len;
233
234 KASSERT(rh != NULL, ("no rx radiotap header"));
235 len = le16toh(rh->it_len);
236
237 if (vap0->iv_flags_ext & IEEE80211_FEXT_BPF)
238 bpf_mtap2(vap0->iv_rawbpf, rh, len, m);
239 /*
240 * Spam monitor mode vaps with unicast frames. Multicast
241 * frames are handled by passing through ieee80211_input_all
242 * which distributes copies to the monitor mode vaps.
243 */
244 if (ic->ic_montaps != 0 && (m->m_flags & M_BCAST) == 0)
245 spam_vaps(vap0, m, rh, len);
246 }
247
248 /*
249 * Dispatch radiotap data for a packet received outside the normal
250 * rx processing path; this is used, for example, to handle frames
251 * received with errors that would otherwise be dropped.
252 */
253 void
254 ieee80211_radiotap_rx_all(struct ieee80211com *ic, struct mbuf *m)
255 {
256 struct ieee80211_radiotap_header *rh = ic->ic_rh;
257 int len = le16toh(rh->it_len);
258 struct ieee80211vap *vap;
259
260 /* XXX locking? */
261 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
262 if (ieee80211_radiotap_active_vap(vap) &&
263 vap->iv_state != IEEE80211_S_INIT)
264 bpf_mtap2(vap->iv_rawbpf, rh, len, m);
265 }
266 }
267
268 /*
269 * Return the offset of the specified item in the radiotap
270 * header description. If the item is not present or is not
271 * known -1 is returned.
272 */
273 static int
274 radiotap_offset(struct ieee80211_radiotap_header *rh,
275 int n_vendor_attributes, int item)
276 {
277 static const struct {
278 size_t align, width;
279 } items[] = {
280 [IEEE80211_RADIOTAP_TSFT] = {
281 .align = sizeof(uint64_t),
282 .width = sizeof(uint64_t),
283 },
284 [IEEE80211_RADIOTAP_FLAGS] = {
285 .align = sizeof(uint8_t),
286 .width = sizeof(uint8_t),
287 },
288 [IEEE80211_RADIOTAP_RATE] = {
289 .align = sizeof(uint8_t),
290 .width = sizeof(uint8_t),
291 },
292 [IEEE80211_RADIOTAP_CHANNEL] = {
293 .align = sizeof(uint16_t),
294 .width = 2*sizeof(uint16_t),
295 },
296 [IEEE80211_RADIOTAP_FHSS] = {
297 .align = sizeof(uint16_t),
298 .width = sizeof(uint16_t),
299 },
300 [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = {
301 .align = sizeof(uint8_t),
302 .width = sizeof(uint8_t),
303 },
304 [IEEE80211_RADIOTAP_DBM_ANTNOISE] = {
305 .align = sizeof(uint8_t),
306 .width = sizeof(uint8_t),
307 },
308 [IEEE80211_RADIOTAP_LOCK_QUALITY] = {
309 .align = sizeof(uint16_t),
310 .width = sizeof(uint16_t),
311 },
312 [IEEE80211_RADIOTAP_TX_ATTENUATION] = {
313 .align = sizeof(uint16_t),
314 .width = sizeof(uint16_t),
315 },
316 [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = {
317 .align = sizeof(uint16_t),
318 .width = sizeof(uint16_t),
319 },
320 [IEEE80211_RADIOTAP_DBM_TX_POWER] = {
321 .align = sizeof(uint8_t),
322 .width = sizeof(uint8_t),
323 },
324 [IEEE80211_RADIOTAP_ANTENNA] = {
325 .align = sizeof(uint8_t),
326 .width = sizeof(uint8_t),
327 },
328 [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = {
329 .align = sizeof(uint8_t),
330 .width = sizeof(uint8_t),
331 },
332 [IEEE80211_RADIOTAP_DB_ANTNOISE] = {
333 .align = sizeof(uint8_t),
334 .width = sizeof(uint8_t),
335 },
336 [IEEE80211_RADIOTAP_XCHANNEL] = {
337 .align = sizeof(uint32_t),
338 .width = 2*sizeof(uint32_t),
339 },
340 [IEEE80211_RADIOTAP_MCS] = {
341 .align = sizeof(uint8_t),
342 .width = 3*sizeof(uint8_t),
343 },
344 };
345 uint32_t present = le32toh(rh->it_present);
346 int off, i;
347
348 off = sizeof(struct ieee80211_radiotap_header);
349 off += n_vendor_attributes * (sizeof(uint32_t));
350
351 for (i = 0; i < IEEE80211_RADIOTAP_EXT; i++) {
352 if ((present & (1<<i)) == 0)
353 continue;
354 if (items[i].align == 0) {
355 /* NB: unidentified element, don't guess */
356 printf("%s: unknown item %d\n", __func__, i);
357 return -1;
358 }
359 off = roundup2(off, items[i].align);
360 if (i == item) {
361 if (off + items[i].width > le16toh(rh->it_len)) {
362 /* NB: item does not fit in header data */
363 printf("%s: item %d not in header data, "
364 "off %d width %zu len %d\n", __func__, i,
365 off, items[i].width, le16toh(rh->it_len));
366 return -1;
367 }
368 return off;
369 }
370 off += items[i].width;
371 }
372 return -1;
373 }
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