1 /* 2 * Copyright 2002-2004, Instant802 Networks, Inc. 3 * Copyright 2008, Jouni Malinen <j@w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 */ 9 10 #include <linux/netdevice.h> 11 #include <linux/types.h> 12 #include <linux/skbuff.h> 13 #include <linux/compiler.h> 14 #include <linux/ieee80211.h> 15 #include <linux/gfp.h> 16 #include <asm/unaligned.h> 17 #include <net/mac80211.h> 18 #include <crypto/aes.h> 19 20 #include "ieee80211_i.h" 21 #include "michael.h" 22 #include "tkip.h" 23 #include "aes_ccm.h" 24 #include "aes_cmac.h" 25 #include "wpa.h" 26 27 ieee80211_tx_result 28 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx) 29 { 30 u8 *data, *key, *mic; 31 size_t data_len; 32 unsigned int hdrlen; 33 struct ieee80211_hdr *hdr; 34 struct sk_buff *skb = tx->skb; 35 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 36 int tail; 37 38 hdr = (struct ieee80211_hdr *)skb->data; 39 if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || 40 skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control)) 41 return TX_CONTINUE; 42 43 hdrlen = ieee80211_hdrlen(hdr->frame_control); 44 if (skb->len < hdrlen) 45 return TX_DROP; 46 47 data = skb->data + hdrlen; 48 data_len = skb->len - hdrlen; 49 50 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) { 51 /* Need to use software crypto for the test */ 52 info->control.hw_key = NULL; 53 } 54 55 if (info->control.hw_key && 56 (info->flags & IEEE80211_TX_CTL_DONTFRAG || 57 tx->local->ops->set_frag_threshold) && 58 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) { 59 /* hwaccel - with no need for SW-generated MMIC */ 60 return TX_CONTINUE; 61 } 62 63 tail = MICHAEL_MIC_LEN; 64 if (!info->control.hw_key) 65 tail += TKIP_ICV_LEN; 66 67 if (WARN_ON(skb_tailroom(skb) < tail || 68 skb_headroom(skb) < TKIP_IV_LEN)) 69 return TX_DROP; 70 71 key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY]; 72 mic = skb_put(skb, MICHAEL_MIC_LEN); 73 michael_mic(key, hdr, data, data_len, mic); 74 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) 75 mic[0]++; 76 77 return TX_CONTINUE; 78 } 79 80 81 ieee80211_rx_result 82 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx) 83 { 84 u8 *data, *key = NULL; 85 size_t data_len; 86 unsigned int hdrlen; 87 u8 mic[MICHAEL_MIC_LEN]; 88 struct sk_buff *skb = rx->skb; 89 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 90 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 91 92 /* 93 * it makes no sense to check for MIC errors on anything other 94 * than data frames. 95 */ 96 if (!ieee80211_is_data_present(hdr->frame_control)) 97 return RX_CONTINUE; 98 99 /* 100 * No way to verify the MIC if the hardware stripped it or 101 * the IV with the key index. In this case we have solely rely 102 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a 103 * MIC failure report. 104 */ 105 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) { 106 if (status->flag & RX_FLAG_MMIC_ERROR) 107 goto mic_fail; 108 109 if (!(status->flag & RX_FLAG_IV_STRIPPED)) 110 goto update_iv; 111 112 return RX_CONTINUE; 113 } 114 115 /* 116 * Some hardware seems to generate Michael MIC failure reports; even 117 * though, the frame was not encrypted with TKIP and therefore has no 118 * MIC. Ignore the flag them to avoid triggering countermeasures. 119 */ 120 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || 121 !(status->flag & RX_FLAG_DECRYPTED)) 122 return RX_CONTINUE; 123 124 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) { 125 /* 126 * APs with pairwise keys should never receive Michael MIC 127 * errors for non-zero keyidx because these are reserved for 128 * group keys and only the AP is sending real multicast 129 * frames in the BSS. ( 130 */ 131 return RX_DROP_UNUSABLE; 132 } 133 134 if (status->flag & RX_FLAG_MMIC_ERROR) 135 goto mic_fail; 136 137 hdrlen = ieee80211_hdrlen(hdr->frame_control); 138 if (skb->len < hdrlen + MICHAEL_MIC_LEN) 139 return RX_DROP_UNUSABLE; 140 141 data = skb->data + hdrlen; 142 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN; 143 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY]; 144 michael_mic(key, hdr, data, data_len, mic); 145 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0) 146 goto mic_fail; 147 148 /* remove Michael MIC from payload */ 149 skb_trim(skb, skb->len - MICHAEL_MIC_LEN); 150 151 update_iv: 152 /* update IV in key information to be able to detect replays */ 153 rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32; 154 rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16; 155 156 return RX_CONTINUE; 157 158 mic_fail: 159 /* 160 * In some cases the key can be unset - e.g. a multicast packet, in 161 * a driver that supports HW encryption. Send up the key idx only if 162 * the key is set. 163 */ 164 mac80211_ev_michael_mic_failure(rx->sdata, 165 rx->key ? rx->key->conf.keyidx : -1, 166 (void *) skb->data, NULL, GFP_ATOMIC); 167 return RX_DROP_UNUSABLE; 168 } 169 170 171 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 172 { 173 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 174 struct ieee80211_key *key = tx->key; 175 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 176 unsigned long flags; 177 unsigned int hdrlen; 178 int len, tail; 179 u8 *pos; 180 181 if (info->control.hw_key && 182 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) { 183 /* hwaccel - with no need for software-generated IV */ 184 return 0; 185 } 186 187 hdrlen = ieee80211_hdrlen(hdr->frame_control); 188 len = skb->len - hdrlen; 189 190 if (info->control.hw_key) 191 tail = 0; 192 else 193 tail = TKIP_ICV_LEN; 194 195 if (WARN_ON(skb_tailroom(skb) < tail || 196 skb_headroom(skb) < TKIP_IV_LEN)) 197 return -1; 198 199 pos = skb_push(skb, TKIP_IV_LEN); 200 memmove(pos, pos + TKIP_IV_LEN, hdrlen); 201 pos += hdrlen; 202 203 /* Increase IV for the frame */ 204 spin_lock_irqsave(&key->u.tkip.txlock, flags); 205 key->u.tkip.tx.iv16++; 206 if (key->u.tkip.tx.iv16 == 0) 207 key->u.tkip.tx.iv32++; 208 pos = ieee80211_tkip_add_iv(pos, key); 209 spin_unlock_irqrestore(&key->u.tkip.txlock, flags); 210 211 /* hwaccel - with software IV */ 212 if (info->control.hw_key) 213 return 0; 214 215 /* Add room for ICV */ 216 skb_put(skb, TKIP_ICV_LEN); 217 218 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm, 219 key, skb, pos, len); 220 } 221 222 223 ieee80211_tx_result 224 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx) 225 { 226 struct sk_buff *skb = tx->skb; 227 228 ieee80211_tx_set_protected(tx); 229 230 do { 231 if (tkip_encrypt_skb(tx, skb) < 0) 232 return TX_DROP; 233 } while ((skb = skb->next)); 234 235 return TX_CONTINUE; 236 } 237 238 239 ieee80211_rx_result 240 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx) 241 { 242 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data; 243 int hdrlen, res, hwaccel = 0; 244 struct ieee80211_key *key = rx->key; 245 struct sk_buff *skb = rx->skb; 246 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 247 248 hdrlen = ieee80211_hdrlen(hdr->frame_control); 249 250 if (!ieee80211_is_data(hdr->frame_control)) 251 return RX_CONTINUE; 252 253 if (!rx->sta || skb->len - hdrlen < 12) 254 return RX_DROP_UNUSABLE; 255 256 /* 257 * Let TKIP code verify IV, but skip decryption. 258 * In the case where hardware checks the IV as well, 259 * we don't even get here, see ieee80211_rx_h_decrypt() 260 */ 261 if (status->flag & RX_FLAG_DECRYPTED) 262 hwaccel = 1; 263 264 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm, 265 key, skb->data + hdrlen, 266 skb->len - hdrlen, rx->sta->sta.addr, 267 hdr->addr1, hwaccel, rx->security_idx, 268 &rx->tkip_iv32, 269 &rx->tkip_iv16); 270 if (res != TKIP_DECRYPT_OK) 271 return RX_DROP_UNUSABLE; 272 273 /* Trim ICV */ 274 skb_trim(skb, skb->len - TKIP_ICV_LEN); 275 276 /* Remove IV */ 277 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen); 278 skb_pull(skb, TKIP_IV_LEN); 279 280 return RX_CONTINUE; 281 } 282 283 284 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, 285 int encrypted) 286 { 287 __le16 mask_fc; 288 int a4_included, mgmt; 289 u8 qos_tid; 290 u8 *b_0, *aad; 291 u16 data_len, len_a; 292 unsigned int hdrlen; 293 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 294 295 memset(scratch, 0, 6 * AES_BLOCK_SIZE); 296 297 b_0 = scratch + 3 * AES_BLOCK_SIZE; 298 aad = scratch + 4 * AES_BLOCK_SIZE; 299 300 /* 301 * Mask FC: zero subtype b4 b5 b6 (if not mgmt) 302 * Retry, PwrMgt, MoreData; set Protected 303 */ 304 mgmt = ieee80211_is_mgmt(hdr->frame_control); 305 mask_fc = hdr->frame_control; 306 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | 307 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA); 308 if (!mgmt) 309 mask_fc &= ~cpu_to_le16(0x0070); 310 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED); 311 312 hdrlen = ieee80211_hdrlen(hdr->frame_control); 313 len_a = hdrlen - 2; 314 a4_included = ieee80211_has_a4(hdr->frame_control); 315 316 if (ieee80211_is_data_qos(hdr->frame_control)) 317 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 318 else 319 qos_tid = 0; 320 321 data_len = skb->len - hdrlen - CCMP_HDR_LEN; 322 if (encrypted) 323 data_len -= CCMP_MIC_LEN; 324 325 /* First block, b_0 */ 326 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */ 327 /* Nonce: Nonce Flags | A2 | PN 328 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7) 329 */ 330 b_0[1] = qos_tid | (mgmt << 4); 331 memcpy(&b_0[2], hdr->addr2, ETH_ALEN); 332 memcpy(&b_0[8], pn, CCMP_PN_LEN); 333 /* l(m) */ 334 put_unaligned_be16(data_len, &b_0[14]); 335 336 /* AAD (extra authenticate-only data) / masked 802.11 header 337 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */ 338 put_unaligned_be16(len_a, &aad[0]); 339 put_unaligned(mask_fc, (__le16 *)&aad[2]); 340 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN); 341 342 /* Mask Seq#, leave Frag# */ 343 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f; 344 aad[23] = 0; 345 346 if (a4_included) { 347 memcpy(&aad[24], hdr->addr4, ETH_ALEN); 348 aad[30] = qos_tid; 349 aad[31] = 0; 350 } else { 351 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN); 352 aad[24] = qos_tid; 353 } 354 } 355 356 357 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id) 358 { 359 hdr[0] = pn[5]; 360 hdr[1] = pn[4]; 361 hdr[2] = 0; 362 hdr[3] = 0x20 | (key_id << 6); 363 hdr[4] = pn[3]; 364 hdr[5] = pn[2]; 365 hdr[6] = pn[1]; 366 hdr[7] = pn[0]; 367 } 368 369 370 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr) 371 { 372 pn[0] = hdr[7]; 373 pn[1] = hdr[6]; 374 pn[2] = hdr[5]; 375 pn[3] = hdr[4]; 376 pn[4] = hdr[1]; 377 pn[5] = hdr[0]; 378 } 379 380 381 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 382 { 383 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 384 struct ieee80211_key *key = tx->key; 385 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 386 int hdrlen, len, tail; 387 u8 *pos; 388 u8 pn[6]; 389 u64 pn64; 390 u8 scratch[6 * AES_BLOCK_SIZE]; 391 392 if (info->control.hw_key && 393 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) { 394 /* 395 * hwaccel has no need for preallocated room for CCMP 396 * header or MIC fields 397 */ 398 return 0; 399 } 400 401 hdrlen = ieee80211_hdrlen(hdr->frame_control); 402 len = skb->len - hdrlen; 403 404 if (info->control.hw_key) 405 tail = 0; 406 else 407 tail = CCMP_MIC_LEN; 408 409 if (WARN_ON(skb_tailroom(skb) < tail || 410 skb_headroom(skb) < CCMP_HDR_LEN)) 411 return -1; 412 413 pos = skb_push(skb, CCMP_HDR_LEN); 414 memmove(pos, pos + CCMP_HDR_LEN, hdrlen); 415 hdr = (struct ieee80211_hdr *) pos; 416 pos += hdrlen; 417 418 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn); 419 420 pn[5] = pn64; 421 pn[4] = pn64 >> 8; 422 pn[3] = pn64 >> 16; 423 pn[2] = pn64 >> 24; 424 pn[1] = pn64 >> 32; 425 pn[0] = pn64 >> 40; 426 427 ccmp_pn2hdr(pos, pn, key->conf.keyidx); 428 429 /* hwaccel - with software CCMP header */ 430 if (info->control.hw_key) 431 return 0; 432 433 pos += CCMP_HDR_LEN; 434 ccmp_special_blocks(skb, pn, scratch, 0); 435 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len, 436 pos, skb_put(skb, CCMP_MIC_LEN)); 437 438 return 0; 439 } 440 441 442 ieee80211_tx_result 443 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx) 444 { 445 struct sk_buff *skb = tx->skb; 446 447 ieee80211_tx_set_protected(tx); 448 449 do { 450 if (ccmp_encrypt_skb(tx, skb) < 0) 451 return TX_DROP; 452 } while ((skb = skb->next)); 453 454 return TX_CONTINUE; 455 } 456 457 458 ieee80211_rx_result 459 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) 460 { 461 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 462 int hdrlen; 463 struct ieee80211_key *key = rx->key; 464 struct sk_buff *skb = rx->skb; 465 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 466 u8 pn[CCMP_PN_LEN]; 467 int data_len; 468 int queue; 469 470 hdrlen = ieee80211_hdrlen(hdr->frame_control); 471 472 if (!ieee80211_is_data(hdr->frame_control) && 473 !ieee80211_is_robust_mgmt_frame(hdr)) 474 return RX_CONTINUE; 475 476 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN; 477 if (!rx->sta || data_len < 0) 478 return RX_DROP_UNUSABLE; 479 480 ccmp_hdr2pn(pn, skb->data + hdrlen); 481 482 queue = rx->security_idx; 483 484 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) { 485 key->u.ccmp.replays++; 486 return RX_DROP_UNUSABLE; 487 } 488 489 if (!(status->flag & RX_FLAG_DECRYPTED)) { 490 u8 scratch[6 * AES_BLOCK_SIZE]; 491 /* hardware didn't decrypt/verify MIC */ 492 ccmp_special_blocks(skb, pn, scratch, 1); 493 494 if (ieee80211_aes_ccm_decrypt( 495 key->u.ccmp.tfm, scratch, 496 skb->data + hdrlen + CCMP_HDR_LEN, data_len, 497 skb->data + skb->len - CCMP_MIC_LEN, 498 skb->data + hdrlen + CCMP_HDR_LEN)) 499 return RX_DROP_UNUSABLE; 500 } 501 502 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN); 503 504 /* Remove CCMP header and MIC */ 505 skb_trim(skb, skb->len - CCMP_MIC_LEN); 506 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen); 507 skb_pull(skb, CCMP_HDR_LEN); 508 509 return RX_CONTINUE; 510 } 511 512 513 static void bip_aad(struct sk_buff *skb, u8 *aad) 514 { 515 /* BIP AAD: FC(masked) || A1 || A2 || A3 */ 516 517 /* FC type/subtype */ 518 aad[0] = skb->data[0]; 519 /* Mask FC Retry, PwrMgt, MoreData flags to zero */ 520 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6)); 521 /* A1 || A2 || A3 */ 522 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN); 523 } 524 525 526 static inline void bip_ipn_set64(u8 *d, u64 pn) 527 { 528 *d++ = pn; 529 *d++ = pn >> 8; 530 *d++ = pn >> 16; 531 *d++ = pn >> 24; 532 *d++ = pn >> 32; 533 *d = pn >> 40; 534 } 535 536 static inline void bip_ipn_swap(u8 *d, const u8 *s) 537 { 538 *d++ = s[5]; 539 *d++ = s[4]; 540 *d++ = s[3]; 541 *d++ = s[2]; 542 *d++ = s[1]; 543 *d = s[0]; 544 } 545 546 547 ieee80211_tx_result 548 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) 549 { 550 struct sk_buff *skb = tx->skb; 551 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 552 struct ieee80211_key *key = tx->key; 553 struct ieee80211_mmie *mmie; 554 u8 aad[20]; 555 u64 pn64; 556 557 if (info->control.hw_key) 558 return 0; 559 560 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie))) 561 return TX_DROP; 562 563 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie)); 564 mmie->element_id = WLAN_EID_MMIE; 565 mmie->length = sizeof(*mmie) - 2; 566 mmie->key_id = cpu_to_le16(key->conf.keyidx); 567 568 /* PN = PN + 1 */ 569 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); 570 571 bip_ipn_set64(mmie->sequence_number, pn64); 572 573 bip_aad(skb, aad); 574 575 /* 576 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) 577 */ 578 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 579 skb->data + 24, skb->len - 24, mmie->mic); 580 581 return TX_CONTINUE; 582 } 583 584 585 ieee80211_rx_result 586 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) 587 { 588 struct sk_buff *skb = rx->skb; 589 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 590 struct ieee80211_key *key = rx->key; 591 struct ieee80211_mmie *mmie; 592 u8 aad[20], mic[8], ipn[6]; 593 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 594 595 if (!ieee80211_is_mgmt(hdr->frame_control)) 596 return RX_CONTINUE; 597 598 if (skb->len < 24 + sizeof(*mmie)) 599 return RX_DROP_UNUSABLE; 600 601 mmie = (struct ieee80211_mmie *) 602 (skb->data + skb->len - sizeof(*mmie)); 603 if (mmie->element_id != WLAN_EID_MMIE || 604 mmie->length != sizeof(*mmie) - 2) 605 return RX_DROP_UNUSABLE; /* Invalid MMIE */ 606 607 bip_ipn_swap(ipn, mmie->sequence_number); 608 609 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) { 610 key->u.aes_cmac.replays++; 611 return RX_DROP_UNUSABLE; 612 } 613 614 if (!(status->flag & RX_FLAG_DECRYPTED)) { 615 /* hardware didn't decrypt/verify MIC */ 616 bip_aad(skb, aad); 617 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 618 skb->data + 24, skb->len - 24, mic); 619 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) { 620 key->u.aes_cmac.icverrors++; 621 return RX_DROP_UNUSABLE; 622 } 623 } 624 625 memcpy(key->u.aes_cmac.rx_pn, ipn, 6); 626 627 /* Remove MMIE */ 628 skb_trim(skb, skb->len - sizeof(*mmie)); 629 630 return RX_CONTINUE; 631 } 632