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 * $FreeBSD: head/sys/net80211/ieee80211_radiotap.c 193761 2009-06-08 21:16:06Z sam $ 26 */ 27 28 /* 29 * IEEE 802.11 radiotap support. 30 */ 31 #include "opt_wlan.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/mbuf.h> 36 #include <sys/malloc.h> 37 #include <sys/endian.h> 38 #include <sys/kernel.h> 39 40 #include <sys/socket.h> 41 42 #include <net/bpf.h> 43 #include <net/if.h> 44 #include <net/if_llc.h> 45 #include <net/if_media.h> 46 #include <net/route.h> 47 48 #include <netproto/802_11/ieee80211_var.h> 49 50 static int radiotap_offset(struct ieee80211_radiotap_header *, 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 #define B(_v) (1<<(_v)) 58 int off; 59 60 th->it_len = htole16(roundup2(tlen, sizeof(uint32_t))); 61 th->it_present = htole32(tx_radiotap); 62 ic->ic_th = th; 63 /* calculate offset to channel data */ 64 off = -1; 65 if (tx_radiotap & B(IEEE80211_RADIOTAP_CHANNEL)) 66 off = radiotap_offset(th, IEEE80211_RADIOTAP_CHANNEL); 67 else if (tx_radiotap & B(IEEE80211_RADIOTAP_XCHANNEL)) 68 off = radiotap_offset(th, IEEE80211_RADIOTAP_XCHANNEL); 69 if (off == -1) { 70 if_printf(ic->ic_ifp, "%s: no tx channel, radiotap 0x%x", 71 __func__, tx_radiotap); 72 /* NB: we handle this case but data will have no chan spec */ 73 } else 74 ic->ic_txchan = ((uint8_t *) th) + off; 75 76 rh->it_len = htole16(roundup2(rlen, sizeof(uint32_t))); 77 rh->it_present = htole32(rx_radiotap); 78 ic->ic_rh = rh; 79 /* calculate offset to channel data */ 80 off = -1; 81 if (rx_radiotap & B(IEEE80211_RADIOTAP_CHANNEL)) 82 off = radiotap_offset(rh, IEEE80211_RADIOTAP_CHANNEL); 83 else if (rx_radiotap & B(IEEE80211_RADIOTAP_XCHANNEL)) 84 off = radiotap_offset(rh, IEEE80211_RADIOTAP_XCHANNEL); 85 if (off == -1) { 86 if_printf(ic->ic_ifp, "%s: no rx channel, radiotap 0x%x", 87 __func__, rx_radiotap); 88 /* NB: we handle this case but data will have no chan spec */ 89 } else 90 ic->ic_rxchan = ((uint8_t *) rh) + off; 91 #undef B 92 } 93 94 void 95 ieee80211_radiotap_detach(struct ieee80211com *ic) 96 { 97 } 98 99 void 100 ieee80211_radiotap_vattach(struct ieee80211vap *vap) 101 { 102 struct ieee80211com *ic = vap->iv_ic; 103 struct ieee80211_radiotap_header *th = ic->ic_th; 104 105 if (th != NULL && ic->ic_rh != NULL) { 106 /* radiotap DLT for raw 802.11 frames */ 107 bpfattach_dlt(vap->iv_ifp, DLT_IEEE802_11_RADIO, 108 sizeof(struct ieee80211_frame) + le16toh(th->it_len), 109 &vap->iv_rawbpf); 110 } 111 } 112 113 void 114 ieee80211_radiotap_vdetach(struct ieee80211vap *vap) 115 { 116 /* NB: bpfattach is called by ether_ifdetach and claims all taps */ 117 } 118 119 static void 120 set_channel(void *p, const struct ieee80211_channel *c) 121 { 122 struct { 123 uint16_t freq; 124 uint16_t flags; 125 } *rc = p; 126 127 rc->freq = htole16(c->ic_freq); 128 rc->flags = htole16(c->ic_flags); 129 } 130 131 static void 132 set_xchannel(void *p, const struct ieee80211_channel *c) 133 { 134 struct { 135 uint32_t flags; 136 uint16_t freq; 137 uint8_t ieee; 138 uint8_t maxpow; 139 } *rc = p; 140 141 rc->flags = htole32(c->ic_flags); 142 rc->freq = htole16(c->ic_freq); 143 rc->ieee = c->ic_ieee; 144 rc->maxpow = c->ic_maxregpower; 145 } 146 147 /* 148 * Update radiotap state on channel change. 149 */ 150 void 151 ieee80211_radiotap_chan_change(struct ieee80211com *ic) 152 { 153 if (ic->ic_rxchan != NULL) { 154 struct ieee80211_radiotap_header *rh = ic->ic_rh; 155 156 if (rh->it_present & htole32(1<<IEEE80211_RADIOTAP_XCHANNEL)) 157 set_xchannel(ic->ic_rxchan, ic->ic_curchan); 158 else if (rh->it_present & htole32(1<<IEEE80211_RADIOTAP_CHANNEL)) 159 set_channel(ic->ic_rxchan, ic->ic_curchan); 160 } 161 if (ic->ic_txchan != NULL) { 162 struct ieee80211_radiotap_header *th = ic->ic_th; 163 164 if (th->it_present & htole32(1<<IEEE80211_RADIOTAP_XCHANNEL)) 165 set_xchannel(ic->ic_txchan, ic->ic_curchan); 166 else if (th->it_present & htole32(1<<IEEE80211_RADIOTAP_CHANNEL)) 167 set_channel(ic->ic_txchan, ic->ic_curchan); 168 } 169 } 170 171 /* 172 * Distribute radiotap data (+packet) to all monitor mode 173 * vaps with an active tap other than vap0. 174 */ 175 static void 176 spam_vaps(struct ieee80211vap *vap0, struct mbuf *m, 177 struct ieee80211_radiotap_header *rh, int len) 178 { 179 struct ieee80211com *ic = vap0->iv_ic; 180 struct ieee80211vap *vap; 181 182 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) { 183 if (vap != vap0 && 184 vap->iv_opmode == IEEE80211_M_MONITOR && 185 (vap->iv_flags_ext & IEEE80211_FEXT_BPF) && 186 vap->iv_state != IEEE80211_S_INIT) { 187 if (vap->iv_rawbpf) { 188 bpf_gettoken(); 189 if (vap->iv_rawbpf) 190 bpf_ptap(vap->iv_rawbpf, m, rh, len); 191 bpf_reltoken(); 192 } 193 } 194 } 195 } 196 197 /* 198 * Dispatch radiotap data for transmitted packet. 199 */ 200 void 201 ieee80211_radiotap_tx(struct ieee80211vap *vap0, struct mbuf *m) 202 { 203 struct ieee80211com *ic = vap0->iv_ic; 204 struct ieee80211_radiotap_header *th = ic->ic_th; 205 int len; 206 207 KASSERT(th != NULL, ("no tx radiotap header")); 208 len = le16toh(th->it_len); 209 210 if (vap0->iv_flags_ext & IEEE80211_FEXT_BPF) { 211 if (vap0->iv_rawbpf) { 212 bpf_gettoken(); 213 if (vap0->iv_rawbpf) 214 bpf_ptap(vap0->iv_rawbpf, m, th, len); 215 bpf_reltoken(); 216 } 217 } 218 /* 219 * Spam monitor mode vaps. 220 */ 221 if (ic->ic_montaps != 0) 222 spam_vaps(vap0, m, th, len); 223 } 224 225 /* 226 * Dispatch radiotap data for received packet. 227 */ 228 void 229 ieee80211_radiotap_rx(struct ieee80211vap *vap0, struct mbuf *m) 230 { 231 struct ieee80211com *ic = vap0->iv_ic; 232 struct ieee80211_radiotap_header *rh = ic->ic_rh; 233 int len; 234 235 KASSERT(rh != NULL, ("no rx radiotap header")); 236 len = le16toh(rh->it_len); 237 238 if (vap0->iv_flags_ext & IEEE80211_FEXT_BPF) { 239 if (vap0->iv_rawbpf) { 240 bpf_gettoken(); 241 if (vap0->iv_rawbpf) 242 bpf_ptap(vap0->iv_rawbpf, m, rh, len); 243 bpf_reltoken(); 244 } 245 } 246 /* 247 * Spam monitor mode vaps with unicast frames. Multicast 248 * frames are handled by passing through ieee80211_input_all 249 * which distributes copies to the monitor mode vaps. 250 */ 251 if (ic->ic_montaps != 0 && (m->m_flags & M_BCAST) == 0) 252 spam_vaps(vap0, m, rh, len); 253 } 254 255 /* 256 * Dispatch radiotap data for a packet received outside the normal 257 * rx processing path; this is used, for example, to handle frames 258 * received with errors that would otherwise be dropped. 259 */ 260 void 261 ieee80211_radiotap_rx_all(struct ieee80211com *ic, struct mbuf *m) 262 { 263 struct ieee80211_radiotap_header *rh = ic->ic_rh; 264 int len = le16toh(rh->it_len); 265 struct ieee80211vap *vap; 266 267 /* XXX locking? */ 268 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) { 269 if (ieee80211_radiotap_active_vap(vap) && 270 vap->iv_state != IEEE80211_S_INIT) { 271 if (vap->iv_rawbpf) { 272 bpf_gettoken(); 273 if (vap->iv_rawbpf) 274 bpf_ptap(vap->iv_rawbpf, m, rh, len); 275 bpf_reltoken(); 276 } 277 } 278 } 279 } 280 281 /* 282 * Return the offset of the specified item in the radiotap 283 * header description. If the item is not present or is not 284 * known -1 is returned. 285 */ 286 static int 287 radiotap_offset(struct ieee80211_radiotap_header *rh, int item) 288 { 289 static const struct { 290 size_t align, width; 291 } items[] = { 292 [IEEE80211_RADIOTAP_TSFT] = { 293 .align = sizeof(uint64_t), 294 .width = sizeof(uint64_t), 295 }, 296 [IEEE80211_RADIOTAP_FLAGS] = { 297 .align = sizeof(uint8_t), 298 .width = sizeof(uint8_t), 299 }, 300 [IEEE80211_RADIOTAP_RATE] = { 301 .align = sizeof(uint8_t), 302 .width = sizeof(uint8_t), 303 }, 304 [IEEE80211_RADIOTAP_CHANNEL] = { 305 .align = sizeof(uint16_t), 306 .width = 2*sizeof(uint16_t), 307 }, 308 [IEEE80211_RADIOTAP_FHSS] = { 309 .align = sizeof(uint16_t), 310 .width = sizeof(uint16_t), 311 }, 312 [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = { 313 .align = sizeof(uint8_t), 314 .width = sizeof(uint8_t), 315 }, 316 [IEEE80211_RADIOTAP_DBM_ANTNOISE] = { 317 .align = sizeof(uint8_t), 318 .width = sizeof(uint8_t), 319 }, 320 [IEEE80211_RADIOTAP_LOCK_QUALITY] = { 321 .align = sizeof(uint16_t), 322 .width = sizeof(uint16_t), 323 }, 324 [IEEE80211_RADIOTAP_TX_ATTENUATION] = { 325 .align = sizeof(uint16_t), 326 .width = sizeof(uint16_t), 327 }, 328 [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = { 329 .align = sizeof(uint16_t), 330 .width = sizeof(uint16_t), 331 }, 332 [IEEE80211_RADIOTAP_DBM_TX_POWER] = { 333 .align = sizeof(uint8_t), 334 .width = sizeof(uint8_t), 335 }, 336 [IEEE80211_RADIOTAP_ANTENNA] = { 337 .align = sizeof(uint8_t), 338 .width = sizeof(uint8_t), 339 }, 340 [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = { 341 .align = sizeof(uint8_t), 342 .width = sizeof(uint8_t), 343 }, 344 [IEEE80211_RADIOTAP_DB_ANTNOISE] = { 345 .align = sizeof(uint8_t), 346 .width = sizeof(uint8_t), 347 }, 348 [IEEE80211_RADIOTAP_XCHANNEL] = { 349 .align = sizeof(uint32_t), 350 .width = 2*sizeof(uint32_t), 351 }, 352 }; 353 uint32_t present = le32toh(rh->it_present); 354 int off, i; 355 356 off = sizeof(struct ieee80211_radiotap_header); 357 for (i = 0; i < IEEE80211_RADIOTAP_EXT; i++) { 358 if ((present & (1<<i)) == 0) 359 continue; 360 if (items[i].align == 0) { 361 /* NB: unidentified element, don't guess */ 362 kprintf("%s: unknown item %d\n", __func__, i); 363 return -1; 364 } 365 off = roundup2(off, items[i].align); 366 if (i == item) { 367 if (off + items[i].width > le16toh(rh->it_len)) { 368 /* NB: item does not fit in header data */ 369 kprintf("%s: item %d not in header data, " 370 "off %d width %zu len %d\n", __func__, i, 371 off, items[i].width, le16toh(rh->it_len)); 372 return -1; 373 } 374 return off; 375 } 376 off += items[i].width; 377 } 378 return -1; 379 } 380