1/* $NetBSD: ieee80211_crypto.c,v 1.14 2006/11/16 01:33:40 christos Exp $ */ 2/*- 3 * Copyright (c) 2001 Atsushi Onoe 4 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting 5 * 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 the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * Alternatively, this software may be distributed under the terms of the 19 * GNU General Public License ("GPL") version 2 as published by the Free 20 * Software Foundation. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34#include <sys/cdefs.h> 35#ifdef __FreeBSD__ 36__FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto.c,v 1.12 2005/08/08 18:46:35 sam Exp $"); 37#endif 38#ifdef __NetBSD__ 39__KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto.c,v 1.14 2006/11/16 01:33:40 christos Exp $"); 40#endif 41 42#include "opt_inet.h" 43 44/* 45 * IEEE 802.11 generic crypto support. 46 */ 47#include <sys/param.h> 48#include <sys/mbuf.h> 49 50#include <sys/socket.h> 51#include <sys/sockio.h> 52#include <sys/endian.h> 53#include <sys/errno.h> 54#include <sys/proc.h> 55#include <sys/sysctl.h> 56 57#include <net/if.h> 58#include <net/if_media.h> 59#include <net/if_arp.h> 60#include <net/if_ether.h> 61#include <net/if_llc.h> 62 63#include <net80211/ieee80211_netbsd.h> 64#include <net80211/ieee80211_var.h> 65 66/* 67 * Table of registered cipher modules. 68 */ 69static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX]; 70 71#ifdef INET 72#include <netinet/in.h> 73#include <net/if_ether.h> 74#endif 75 76static int _ieee80211_crypto_delkey(struct ieee80211com *, 77 struct ieee80211_key *); 78 79/* 80 * Default "null" key management routines. 81 */ 82static int 83null_key_alloc(struct ieee80211com *ic, const struct ieee80211_key *k, 84 ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix) 85{ 86 if (!(&ic->ic_nw_keys[0] <= k && 87 k < &ic->ic_nw_keys[IEEE80211_WEP_NKID])) { 88 /* 89 * Not in the global key table, the driver should handle this 90 * by allocating a slot in the h/w key table/cache. In 91 * lieu of that return key slot 0 for any unicast key 92 * request. We disallow the request if this is a group key. 93 * This default policy does the right thing for legacy hardware 94 * with a 4 key table. It also handles devices that pass 95 * packets through untouched when marked with the WEP bit 96 * and key index 0. 97 */ 98 if (k->wk_flags & IEEE80211_KEY_GROUP) 99 return 0; 100 *keyix = 0; /* NB: use key index 0 for ucast key */ 101 } else { 102 *keyix = k - ic->ic_nw_keys; 103 } 104 *rxkeyix = IEEE80211_KEYIX_NONE; /* XXX maybe *keyix? */ 105 return 1; 106} 107static int 108null_key_delete(struct ieee80211com *ic, 109 const struct ieee80211_key *k) 110{ 111 return 1; 112} 113static int 114null_key_set(struct ieee80211com *ic, 115 const struct ieee80211_key *k, 116 const u_int8_t mac[IEEE80211_ADDR_LEN]) 117{ 118 return 1; 119} 120static void null_key_update(struct ieee80211com *ic) {} 121 122/* 123 * Write-arounds for common operations. 124 */ 125static __inline void 126cipher_detach(struct ieee80211_key *key) 127{ 128 key->wk_cipher->ic_detach(key); 129} 130 131static __inline void * 132cipher_attach(struct ieee80211com *ic, struct ieee80211_key *key) 133{ 134 return key->wk_cipher->ic_attach(ic, key); 135} 136 137/* 138 * Wrappers for driver key management methods. 139 */ 140static __inline int 141dev_key_alloc(struct ieee80211com *ic, 142 const struct ieee80211_key *key, 143 ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix) 144{ 145 return ic->ic_crypto.cs_key_alloc(ic, key, keyix, rxkeyix); 146} 147 148static __inline int 149dev_key_delete(struct ieee80211com *ic, 150 const struct ieee80211_key *key) 151{ 152 return ic->ic_crypto.cs_key_delete(ic, key); 153} 154 155static __inline int 156dev_key_set(struct ieee80211com *ic, const struct ieee80211_key *key, 157 const u_int8_t mac[IEEE80211_ADDR_LEN]) 158{ 159 return ic->ic_crypto.cs_key_set(ic, key, mac); 160} 161 162/* 163 * Setup crypto support. 164 */ 165void 166ieee80211_crypto_attach(struct ieee80211com *ic) 167{ 168 struct ieee80211_crypto_state *cs = &ic->ic_crypto; 169 int i; 170 171 /* NB: we assume everything is pre-zero'd */ 172 cs->cs_def_txkey = IEEE80211_KEYIX_NONE; 173 cs->cs_max_keyix = IEEE80211_WEP_NKID; 174 ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none; 175 for (i = 0; i < IEEE80211_WEP_NKID; i++) 176 ieee80211_crypto_resetkey(ic, &cs->cs_nw_keys[i], 177 IEEE80211_KEYIX_NONE); 178 /* 179 * Initialize the driver key support routines to noop entries. 180 * This is useful especially for the cipher test modules. 181 */ 182 cs->cs_key_alloc = null_key_alloc; 183 cs->cs_key_set = null_key_set; 184 cs->cs_key_delete = null_key_delete; 185 cs->cs_key_update_begin = null_key_update; 186 cs->cs_key_update_end = null_key_update; 187} 188 189/* 190 * Teardown crypto support. 191 */ 192void 193ieee80211_crypto_detach(struct ieee80211com *ic) 194{ 195 ieee80211_crypto_delglobalkeys(ic); 196} 197 198/* 199 * Register a crypto cipher module. 200 */ 201void 202ieee80211_crypto_register(const struct ieee80211_cipher *cip) 203{ 204 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 205 printf("%s: cipher %s has an invalid cipher index %u\n", 206 __func__, cip->ic_name, cip->ic_cipher); 207 return; 208 } 209 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 210 printf("%s: cipher %s registered with a different template\n", 211 __func__, cip->ic_name); 212 return; 213 } 214 ciphers[cip->ic_cipher] = cip; 215} 216 217/* 218 * Unregister a crypto cipher module. 219 */ 220void 221ieee80211_crypto_unregister(const struct ieee80211_cipher *cip) 222{ 223 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 224 printf("%s: cipher %s has an invalid cipher index %u\n", 225 __func__, cip->ic_name, cip->ic_cipher); 226 return; 227 } 228 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 229 printf("%s: cipher %s registered with a different template\n", 230 __func__, cip->ic_name); 231 return; 232 } 233 /* NB: don't complain about not being registered */ 234 /* XXX disallow if references */ 235 ciphers[cip->ic_cipher] = NULL; 236} 237 238int 239ieee80211_crypto_available(u_int cipher) 240{ 241 return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL; 242} 243 244/* XXX well-known names! */ 245static const char *cipher_modnames[] = { 246 "wlan_wep", /* IEEE80211_CIPHER_WEP */ 247 "wlan_tkip", /* IEEE80211_CIPHER_TKIP */ 248 "wlan_aes_ocb", /* IEEE80211_CIPHER_AES_OCB */ 249 "wlan_ccmp", /* IEEE80211_CIPHER_AES_CCM */ 250 "wlan_ckip", /* IEEE80211_CIPHER_CKIP */ 251}; 252 253/* 254 * Establish a relationship between the specified key and cipher 255 * and, if necessary, allocate a hardware index from the driver. 256 * Note that when a fixed key index is required it must be specified 257 * and we blindly assign it w/o consulting the driver (XXX). 258 * 259 * This must be the first call applied to a key; all the other key 260 * routines assume wk_cipher is setup. 261 * 262 * Locking must be handled by the caller using: 263 * ieee80211_key_update_begin(ic); 264 * ieee80211_key_update_end(ic); 265 */ 266int 267ieee80211_crypto_newkey(struct ieee80211com *ic, 268 int cipher, int flags, struct ieee80211_key *key) 269{ 270#define N(a) (sizeof(a) / sizeof(a[0])) 271 const struct ieee80211_cipher *cip; 272 ieee80211_keyix keyix, rxkeyix; 273 void *keyctx; 274 int oflags; 275 276 /* 277 * Validate cipher and set reference to cipher routines. 278 */ 279 if (cipher >= IEEE80211_CIPHER_MAX) { 280 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 281 "%s: invalid cipher %u\n", __func__, cipher); 282 ic->ic_stats.is_crypto_badcipher++; 283 return 0; 284 } 285 cip = ciphers[cipher]; 286 if (cip == NULL) { 287 /* 288 * Auto-load cipher module if we have a well-known name 289 * for it. It might be better to use string names rather 290 * than numbers and craft a module name based on the cipher 291 * name; e.g. wlan_cipher_<cipher-name>. 292 */ 293 if (cipher < N(cipher_modnames)) { 294 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 295 "%s: unregistered cipher %u, load module %s\n", 296 __func__, cipher, cipher_modnames[cipher]); 297 ieee80211_load_module(cipher_modnames[cipher]); 298 /* 299 * If cipher module loaded it should immediately 300 * call ieee80211_crypto_register which will fill 301 * in the entry in the ciphers array. 302 */ 303 cip = ciphers[cipher]; 304 } 305 if (cip == NULL) { 306 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 307 "%s: unable to load cipher %u, module %s\n", 308 __func__, cipher, 309 cipher < N(cipher_modnames) ? 310 cipher_modnames[cipher] : "<unknown>"); 311 ic->ic_stats.is_crypto_nocipher++; 312 return 0; 313 } 314 } 315 316 oflags = key->wk_flags; 317 flags &= IEEE80211_KEY_COMMON; 318 /* 319 * If the hardware does not support the cipher then 320 * fallback to a host-based implementation. 321 */ 322 if ((ic->ic_caps & (1<<cipher)) == 0) { 323 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 324 "%s: no h/w support for cipher %s, falling back to s/w\n", 325 __func__, cip->ic_name); 326 flags |= IEEE80211_KEY_SWCRYPT; 327 } 328 /* 329 * Hardware TKIP with software MIC is an important 330 * combination; we handle it by flagging each key, 331 * the cipher modules honor it. 332 */ 333 if (cipher == IEEE80211_CIPHER_TKIP && 334 (ic->ic_caps & IEEE80211_C_TKIPMIC) == 0) { 335 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 336 "%s: no h/w support for TKIP MIC, falling back to s/w\n", 337 __func__); 338 flags |= IEEE80211_KEY_SWMIC; 339 } 340 341 /* 342 * Bind cipher to key instance. Note we do this 343 * after checking the device capabilities so the 344 * cipher module can optimize space usage based on 345 * whether or not it needs to do the cipher work. 346 */ 347 if (key->wk_cipher != cip || key->wk_flags != flags) { 348again: 349 /* 350 * Fillin the flags so cipher modules can see s/w 351 * crypto requirements and potentially allocate 352 * different state and/or attach different method 353 * pointers. 354 * 355 * XXX this is not right when s/w crypto fallback 356 * fails and we try to restore previous state. 357 */ 358 key->wk_flags = flags; 359 keyctx = cip->ic_attach(ic, key); 360 if (keyctx == NULL) { 361 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 362 "%s: unable to attach cipher %s\n", 363 __func__, cip->ic_name); 364 key->wk_flags = oflags; /* restore old flags */ 365 ic->ic_stats.is_crypto_attachfail++; 366 return 0; 367 } 368 cipher_detach(key); 369 key->wk_cipher = cip; /* XXX refcnt? */ 370 key->wk_private = keyctx; 371 } 372 /* 373 * Commit to requested usage so driver can see the flags. 374 */ 375 key->wk_flags = flags; 376 377 /* 378 * Ask the driver for a key index if we don't have one. 379 * Note that entries in the global key table always have 380 * an index; this means it's safe to call this routine 381 * for these entries just to setup the reference to the 382 * cipher template. Note also that when using software 383 * crypto we also call the driver to give us a key index. 384 */ 385 if (key->wk_keyix == IEEE80211_KEYIX_NONE) { 386 if (!dev_key_alloc(ic, key, &keyix, &rxkeyix)) { 387 /* 388 * Driver has no room; fallback to doing crypto 389 * in the host. We change the flags and start the 390 * procedure over. If we get back here then there's 391 * no hope and we bail. Note that this can leave 392 * the key in a inconsistent state if the caller 393 * continues to use it. 394 */ 395 if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) { 396 ic->ic_stats.is_crypto_swfallback++; 397 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 398 "%s: no h/w resources for cipher %s, " 399 "falling back to s/w\n", __func__, 400 cip->ic_name); 401 oflags = key->wk_flags; 402 flags |= IEEE80211_KEY_SWCRYPT; 403 if (cipher == IEEE80211_CIPHER_TKIP) 404 flags |= IEEE80211_KEY_SWMIC; 405 goto again; 406 } 407 ic->ic_stats.is_crypto_keyfail++; 408 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 409 "%s: unable to setup cipher %s\n", 410 __func__, cip->ic_name); 411 return 0; 412 } 413 key->wk_keyix = keyix; 414 key->wk_rxkeyix = rxkeyix; 415 } 416 return 1; 417#undef N 418} 419 420/* 421 * Remove the key (no locking, for internal use). 422 */ 423static int 424_ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key) 425{ 426 ieee80211_keyix keyix; 427 428 IASSERT(key->wk_cipher != NULL, ("No cipher!")); 429 430 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 431 "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n", 432 __func__, key->wk_cipher->ic_name, 433 key->wk_keyix, key->wk_flags, 434 key->wk_keyrsc, key->wk_keytsc, key->wk_keylen); 435 436 keyix = key->wk_keyix; 437 if (keyix != IEEE80211_KEYIX_NONE) { 438 /* 439 * Remove hardware entry. 440 */ 441 /* XXX key cache */ 442 if (!dev_key_delete(ic, key)) { 443 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 444 "%s: driver did not delete key index %u\n", 445 __func__, keyix); 446 ic->ic_stats.is_crypto_delkey++; 447 /* XXX recovery? */ 448 } 449 } 450 cipher_detach(key); 451 memset(key, 0, sizeof(*key)); 452 ieee80211_crypto_resetkey(ic, key, IEEE80211_KEYIX_NONE); 453 return 1; 454} 455 456/* 457 * Remove the specified key. 458 */ 459int 460ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key) 461{ 462 int status; 463 464 ieee80211_key_update_begin(ic); 465 status = _ieee80211_crypto_delkey(ic, key); 466 ieee80211_key_update_end(ic); 467 return status; 468} 469 470/* 471 * Clear the global key table. 472 */ 473void 474ieee80211_crypto_delglobalkeys(struct ieee80211com *ic) 475{ 476 int i; 477 478 ieee80211_key_update_begin(ic); 479 for (i = 0; i < IEEE80211_WEP_NKID; i++) 480 (void) _ieee80211_crypto_delkey(ic, &ic->ic_nw_keys[i]); 481 ieee80211_key_update_end(ic); 482} 483 484/* 485 * Set the contents of the specified key. 486 * 487 * Locking must be handled by the caller using: 488 * ieee80211_key_update_begin(ic); 489 * ieee80211_key_update_end(ic); 490 */ 491int 492ieee80211_crypto_setkey(struct ieee80211com *ic, struct ieee80211_key *key, 493 const u_int8_t macaddr[IEEE80211_ADDR_LEN]) 494{ 495 const struct ieee80211_cipher *cip = key->wk_cipher; 496 497 IASSERT(cip != NULL, ("No cipher!")); 498 499 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 500 "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n", 501 __func__, cip->ic_name, key->wk_keyix, 502 key->wk_flags, ether_sprintf(macaddr), 503 key->wk_keyrsc, key->wk_keytsc, key->wk_keylen); 504 505 /* 506 * Give cipher a chance to validate key contents. 507 * XXX should happen before modifying state. 508 */ 509 if (!cip->ic_setkey(key)) { 510 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 511 "%s: cipher %s rejected key index %u len %u flags 0x%x\n", 512 __func__, cip->ic_name, key->wk_keyix, 513 key->wk_keylen, key->wk_flags); 514 ic->ic_stats.is_crypto_setkey_cipher++; 515 return 0; 516 } 517 if (key->wk_keyix == IEEE80211_KEYIX_NONE) { 518 /* XXX nothing allocated, should not happen */ 519 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 520 "%s: no key index; should not happen!\n", __func__); 521 ic->ic_stats.is_crypto_setkey_nokey++; 522 return 0; 523 } 524 return dev_key_set(ic, key, macaddr); 525} 526 527/* 528 * Add privacy headers appropriate for the specified key. 529 */ 530struct ieee80211_key * 531ieee80211_crypto_encap(struct ieee80211com *ic, 532 struct ieee80211_node *ni, struct mbuf *m) 533{ 534 struct ieee80211_key *k; 535 struct ieee80211_frame *wh; 536 const struct ieee80211_cipher *cip; 537 u_int8_t keyid; 538 539 /* 540 * Multicast traffic always uses the multicast key. 541 * Otherwise if a unicast key is set we use that and 542 * it is always key index 0. When no unicast key is 543 * set we fall back to the default transmit key. 544 */ 545 wh = mtod(m, struct ieee80211_frame *); 546 if (IEEE80211_IS_MULTICAST(wh->i_addr1) || 547 ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) { 548 if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE) { 549 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 550 "[%s] no default transmit key (%s) deftxkey %u\n", 551 ether_sprintf(wh->i_addr1), __func__, 552 ic->ic_def_txkey); 553 ic->ic_stats.is_tx_nodefkey++; 554 return NULL; 555 } 556 keyid = ic->ic_def_txkey; 557 k = &ic->ic_nw_keys[ic->ic_def_txkey]; 558 } else { 559 keyid = 0; 560 k = &ni->ni_ucastkey; 561 } 562 cip = k->wk_cipher; 563 return (cip->ic_encap(k, m, keyid<<6) ? k : NULL); 564} 565 566/* 567 * Validate and strip privacy headers (and trailer) for a 568 * received frame that has the WEP/Privacy bit set. 569 */ 570struct ieee80211_key * 571ieee80211_crypto_decap(struct ieee80211com *ic, 572 struct ieee80211_node *ni, struct mbuf *m, int hdrlen) 573{ 574#define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN) 575#define IEEE80211_WEP_MINLEN \ 576 (sizeof(struct ieee80211_frame) + \ 577 IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN) 578 struct ieee80211_key *k; 579 struct ieee80211_frame *wh; 580 const struct ieee80211_cipher *cip; 581 u_int8_t keyid; 582 583 /* NB: this minimum size data frame could be bigger */ 584 if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) { 585 IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY, 586 "%s: WEP data frame too short, len %u\n", 587 __func__, m->m_pkthdr.len); 588 ic->ic_stats.is_rx_tooshort++; /* XXX need unique stat? */ 589 return NULL; 590 } 591 592 /* 593 * Locate the key. If unicast and there is no unicast 594 * key then we fall back to the key id in the header. 595 * This assumes unicast keys are only configured when 596 * the key id in the header is meaningless (typically 0). 597 */ 598 wh = mtod(m, struct ieee80211_frame *); 599 m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid); 600 if (IEEE80211_IS_MULTICAST(wh->i_addr1) || 601 ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) 602 k = &ic->ic_nw_keys[keyid >> 6]; 603 else 604 k = &ni->ni_ucastkey; 605 606 /* 607 * Insure crypto header is contiguous for all decap work. 608 */ 609 cip = k->wk_cipher; 610 if (m->m_len < hdrlen + cip->ic_header && 611 (m = m_pullup(m, hdrlen + cip->ic_header)) == NULL) { 612 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO, 613 "[%s] unable to pullup %s header\n", 614 ether_sprintf(wh->i_addr2), cip->ic_name); 615 ic->ic_stats.is_rx_wepfail++; /* XXX */ 616 return NULL; 617 } 618 619 return (cip->ic_decap(k, m, hdrlen) ? k : NULL); 620#undef IEEE80211_WEP_MINLEN 621#undef IEEE80211_WEP_HDRLEN 622} 623