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 bpf_ptap(vap->iv_rawbpf, m, rh, len); 188 } 189 } 190 191 /* 192 * Dispatch radiotap data for transmitted packet. 193 */ 194 void 195 ieee80211_radiotap_tx(struct ieee80211vap *vap0, struct mbuf *m) 196 { 197 struct ieee80211com *ic = vap0->iv_ic; 198 struct ieee80211_radiotap_header *th = ic->ic_th; 199 int len; 200 201 KASSERT(th != NULL, ("no tx radiotap header")); 202 len = le16toh(th->it_len); 203 204 if (vap0->iv_flags_ext & IEEE80211_FEXT_BPF) 205 bpf_ptap(vap0->iv_rawbpf, m, th, len); 206 /* 207 * Spam monitor mode vaps. 208 */ 209 if (ic->ic_montaps != 0) 210 spam_vaps(vap0, m, th, len); 211 } 212 213 /* 214 * Dispatch radiotap data for received packet. 215 */ 216 void 217 ieee80211_radiotap_rx(struct ieee80211vap *vap0, struct mbuf *m) 218 { 219 struct ieee80211com *ic = vap0->iv_ic; 220 struct ieee80211_radiotap_header *rh = ic->ic_rh; 221 int len; 222 223 KASSERT(rh != NULL, ("no rx radiotap header")); 224 len = le16toh(rh->it_len); 225 226 if (vap0->iv_flags_ext & IEEE80211_FEXT_BPF) 227 bpf_ptap(vap0->iv_rawbpf, m, rh, len); 228 /* 229 * Spam monitor mode vaps with unicast frames. Multicast 230 * frames are handled by passing through ieee80211_input_all 231 * which distributes copies to the monitor mode vaps. 232 */ 233 if (ic->ic_montaps != 0 && (m->m_flags & M_BCAST) == 0) 234 spam_vaps(vap0, m, rh, len); 235 } 236 237 /* 238 * Dispatch radiotap data for a packet received outside the normal 239 * rx processing path; this is used, for example, to handle frames 240 * received with errors that would otherwise be dropped. 241 */ 242 void 243 ieee80211_radiotap_rx_all(struct ieee80211com *ic, struct mbuf *m) 244 { 245 struct ieee80211_radiotap_header *rh = ic->ic_rh; 246 int len = le16toh(rh->it_len); 247 struct ieee80211vap *vap; 248 249 /* XXX locking? */ 250 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) { 251 if (ieee80211_radiotap_active_vap(vap) && 252 vap->iv_state != IEEE80211_S_INIT) 253 bpf_ptap(vap->iv_rawbpf, m, rh, len); 254 } 255 } 256 257 /* 258 * Return the offset of the specified item in the radiotap 259 * header description. If the item is not present or is not 260 * known -1 is returned. 261 */ 262 static int 263 radiotap_offset(struct ieee80211_radiotap_header *rh, int item) 264 { 265 static const struct { 266 size_t align, width; 267 } items[] = { 268 [IEEE80211_RADIOTAP_TSFT] = { 269 .align = sizeof(uint64_t), 270 .width = sizeof(uint64_t), 271 }, 272 [IEEE80211_RADIOTAP_FLAGS] = { 273 .align = sizeof(uint8_t), 274 .width = sizeof(uint8_t), 275 }, 276 [IEEE80211_RADIOTAP_RATE] = { 277 .align = sizeof(uint8_t), 278 .width = sizeof(uint8_t), 279 }, 280 [IEEE80211_RADIOTAP_CHANNEL] = { 281 .align = sizeof(uint16_t), 282 .width = 2*sizeof(uint16_t), 283 }, 284 [IEEE80211_RADIOTAP_FHSS] = { 285 .align = sizeof(uint16_t), 286 .width = sizeof(uint16_t), 287 }, 288 [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = { 289 .align = sizeof(uint8_t), 290 .width = sizeof(uint8_t), 291 }, 292 [IEEE80211_RADIOTAP_DBM_ANTNOISE] = { 293 .align = sizeof(uint8_t), 294 .width = sizeof(uint8_t), 295 }, 296 [IEEE80211_RADIOTAP_LOCK_QUALITY] = { 297 .align = sizeof(uint16_t), 298 .width = sizeof(uint16_t), 299 }, 300 [IEEE80211_RADIOTAP_TX_ATTENUATION] = { 301 .align = sizeof(uint16_t), 302 .width = sizeof(uint16_t), 303 }, 304 [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = { 305 .align = sizeof(uint16_t), 306 .width = sizeof(uint16_t), 307 }, 308 [IEEE80211_RADIOTAP_DBM_TX_POWER] = { 309 .align = sizeof(uint8_t), 310 .width = sizeof(uint8_t), 311 }, 312 [IEEE80211_RADIOTAP_ANTENNA] = { 313 .align = sizeof(uint8_t), 314 .width = sizeof(uint8_t), 315 }, 316 [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = { 317 .align = sizeof(uint8_t), 318 .width = sizeof(uint8_t), 319 }, 320 [IEEE80211_RADIOTAP_DB_ANTNOISE] = { 321 .align = sizeof(uint8_t), 322 .width = sizeof(uint8_t), 323 }, 324 [IEEE80211_RADIOTAP_XCHANNEL] = { 325 .align = sizeof(uint32_t), 326 .width = 2*sizeof(uint32_t), 327 }, 328 }; 329 uint32_t present = le32toh(rh->it_present); 330 int off, i; 331 332 off = sizeof(struct ieee80211_radiotap_header); 333 for (i = 0; i < IEEE80211_RADIOTAP_EXT; i++) { 334 if ((present & (1<<i)) == 0) 335 continue; 336 if (items[i].align == 0) { 337 /* NB: unidentified element, don't guess */ 338 kprintf("%s: unknown item %d\n", __func__, i); 339 return -1; 340 } 341 off = roundup2(off, items[i].align); 342 if (i == item) { 343 if (off + items[i].width > le16toh(rh->it_len)) { 344 /* NB: item does not fit in header data */ 345 kprintf("%s: item %d not in header data, " 346 "off %d width %zu len %d\n", __func__, i, 347 off, items[i].width, le16toh(rh->it_len)); 348 return -1; 349 } 350 return off; 351 } 352 off += items[i].width; 353 } 354 return -1; 355 } 356