334 lines
8.3 KiB
C
334 lines
8.3 KiB
C
/* $NetBSD: ieee80211_crypto.c,v 1.4 2003/09/23 16:03:46 dyoung Exp $ */
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/*-
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* Copyright (c) 2001 Atsushi Onoe
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* Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifdef __FreeBSD__
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__FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto.c,v 1.2 2003/06/27 05:13:52 sam Exp $");
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#else
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__KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto.c,v 1.4 2003/09/23 16:03:46 dyoung Exp $");
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#endif
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#include "opt_inet.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/malloc.h>
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#include <sys/kernel.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <sys/endian.h>
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#include <sys/errno.h>
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#ifdef __FreeBSD__
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#include <sys/bus.h>
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#endif
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#include <sys/proc.h>
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#include <sys/sysctl.h>
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#ifdef __FreeBSD__
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#include <machine/atomic.h>
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#endif
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/if_media.h>
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#include <net/if_arp.h>
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#ifdef __FreeBSD__
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#include <net/ethernet.h>
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#else
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#include <net/if_ether.h>
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#endif
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#include <net/if_llc.h>
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#include <net80211/ieee80211_var.h>
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#include <net80211/ieee80211_compat.h>
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#include <net/bpf.h>
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#ifdef INET
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#include <netinet/in.h>
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#ifdef __FreeBSD__
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#include <netinet/if_ether.h>
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#else
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#include <net/if_ether.h>
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#endif
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#endif
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#ifdef __FreeBSD__
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#include <crypto/rc4/rc4.h>
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#define arc4_ctxlen() sizeof (struct rc4_state)
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#define arc4_setkey(_c,_k,_l) rc4_init(_c,_k,_l)
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#define arc4_encrypt(_c,_d,_s,_l) rc4_crypt(_c,_s,_d,_l)
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#else
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#include <crypto/arc4/arc4.h>
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#endif
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static void ieee80211_crc_init(void);
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static u_int32_t ieee80211_crc_update(u_int32_t crc, u_int8_t *buf, int len);
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void
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ieee80211_crypto_attach(struct ifnet *ifp)
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{
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struct ieee80211com *ic = (void *)ifp;
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/*
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* Setup crypto support.
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*/
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ieee80211_crc_init();
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ic->ic_iv = arc4random();
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}
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void
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ieee80211_crypto_detach(struct ifnet *ifp)
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{
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struct ieee80211com *ic = (void *)ifp;
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if (ic->ic_wep_ctx != NULL) {
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free(ic->ic_wep_ctx, M_DEVBUF);
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ic->ic_wep_ctx = NULL;
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}
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}
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struct mbuf *
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ieee80211_wep_crypt(struct ifnet *ifp, struct mbuf *m0, int txflag)
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{
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struct ieee80211com *ic = (void *)ifp;
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struct mbuf *m, *n, *n0;
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struct ieee80211_frame *wh;
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int i, left, len, moff, noff, kid;
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u_int32_t iv, crc;
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u_int8_t *ivp;
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void *ctx;
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u_int8_t keybuf[IEEE80211_WEP_IVLEN + IEEE80211_KEYBUF_SIZE];
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u_int8_t crcbuf[IEEE80211_WEP_CRCLEN];
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n0 = NULL;
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if ((ctx = ic->ic_wep_ctx) == NULL) {
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ctx = malloc(arc4_ctxlen(), M_DEVBUF, M_NOWAIT);
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if (ctx == NULL)
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goto fail;
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ic->ic_wep_ctx = ctx;
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}
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m = m0;
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left = m->m_pkthdr.len;
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MGET(n, M_DONTWAIT, m->m_type);
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n0 = n;
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if (n == NULL)
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goto fail;
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#ifdef __FreeBSD__
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M_MOVE_PKTHDR(n, m);
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#else
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M_COPY_PKTHDR(n, m);
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#endif
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len = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + IEEE80211_WEP_CRCLEN;
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if (txflag) {
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n->m_pkthdr.len += len;
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} else {
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n->m_pkthdr.len -= len;
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left -= len;
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}
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n->m_len = MHLEN;
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if (n->m_pkthdr.len >= MINCLSIZE) {
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MCLGET(n, M_DONTWAIT);
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if (n->m_flags & M_EXT)
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n->m_len = n->m_ext.ext_size;
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}
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len = sizeof(struct ieee80211_frame);
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memcpy(mtod(n, caddr_t), mtod(m, caddr_t), len);
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wh = mtod(n, struct ieee80211_frame *);
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left -= len;
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moff = len;
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noff = len;
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if (txflag) {
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kid = ic->ic_wep_txkey;
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wh->i_fc[1] |= IEEE80211_FC1_WEP;
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iv = ic->ic_iv;
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/*
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* Skip 'bad' IVs from Fluhrer/Mantin/Shamir:
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* (B, 255, N) with 3 <= B < 8
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*/
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if (iv >= 0x03ff00 &&
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(iv & 0xf8ff00) == 0x00ff00)
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iv += 0x000100;
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ic->ic_iv = iv + 1;
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/* put iv in little endian to prepare 802.11i */
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ivp = mtod(n, u_int8_t *) + noff;
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for (i = 0; i < IEEE80211_WEP_IVLEN; i++) {
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ivp[i] = iv & 0xff;
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iv >>= 8;
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}
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ivp[IEEE80211_WEP_IVLEN] = kid << 6; /* pad and keyid */
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noff += IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN;
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} else {
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wh->i_fc[1] &= ~IEEE80211_FC1_WEP;
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ivp = mtod(m, u_int8_t *) + moff;
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kid = ivp[IEEE80211_WEP_IVLEN] >> 6;
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moff += IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN;
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}
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memcpy(keybuf, ivp, IEEE80211_WEP_IVLEN);
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memcpy(keybuf + IEEE80211_WEP_IVLEN, ic->ic_nw_keys[kid].wk_key,
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ic->ic_nw_keys[kid].wk_len);
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arc4_setkey(ctx, keybuf,
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IEEE80211_WEP_IVLEN + ic->ic_nw_keys[kid].wk_len);
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/* encrypt with calculating CRC */
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crc = ~0;
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while (left > 0) {
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len = m->m_len - moff;
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if (len == 0) {
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m = m->m_next;
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moff = 0;
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continue;
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}
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if (len > n->m_len - noff) {
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len = n->m_len - noff;
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if (len == 0) {
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MGET(n->m_next, M_DONTWAIT, n->m_type);
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if (n->m_next == NULL)
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goto fail;
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n = n->m_next;
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n->m_len = MLEN;
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if (left >= MINCLSIZE) {
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MCLGET(n, M_DONTWAIT);
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if (n->m_flags & M_EXT)
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n->m_len = n->m_ext.ext_size;
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}
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noff = 0;
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continue;
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}
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}
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if (len > left)
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len = left;
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arc4_encrypt(ctx, mtod(n, caddr_t) + noff,
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mtod(m, caddr_t) + moff, len);
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if (txflag)
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crc = ieee80211_crc_update(crc,
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mtod(m, u_int8_t *) + moff, len);
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else
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crc = ieee80211_crc_update(crc,
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mtod(n, u_int8_t *) + noff, len);
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left -= len;
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moff += len;
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noff += len;
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}
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crc = ~crc;
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if (txflag) {
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*(u_int32_t *)crcbuf = htole32(crc);
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if (n->m_len >= noff + sizeof(crcbuf))
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n->m_len = noff + sizeof(crcbuf);
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else {
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n->m_len = noff;
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MGET(n->m_next, M_DONTWAIT, n->m_type);
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if (n->m_next == NULL)
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goto fail;
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n = n->m_next;
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n->m_len = sizeof(crcbuf);
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noff = 0;
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}
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arc4_encrypt(ctx, mtod(n, caddr_t) + noff, crcbuf,
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sizeof(crcbuf));
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} else {
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n->m_len = noff;
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for (noff = 0; noff < sizeof(crcbuf); noff += len) {
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len = sizeof(crcbuf) - noff;
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if (len > m->m_len - moff)
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len = m->m_len - moff;
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if (len > 0)
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arc4_encrypt(ctx, crcbuf + noff,
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mtod(m, caddr_t) + moff, len);
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m = m->m_next;
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moff = 0;
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}
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if (crc != le32toh(*(u_int32_t *)crcbuf)) {
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#ifdef IEEE80211_DEBUG
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if (ieee80211_debug) {
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if_printf(ifp, "decrypt CRC error\n");
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if (ieee80211_debug > 1)
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ieee80211_dump_pkt(n0->m_data,
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n0->m_len, -1, -1);
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}
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#endif
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goto fail;
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}
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}
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m_freem(m0);
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return n0;
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fail:
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m_freem(m0);
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m_freem(n0);
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return NULL;
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}
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/*
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* CRC 32 -- routine from RFC 2083
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*/
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/* Table of CRCs of all 8-bit messages */
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static u_int32_t ieee80211_crc_table[256];
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/* Make the table for a fast CRC. */
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static void
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ieee80211_crc_init(void)
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{
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u_int32_t c;
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int n, k;
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for (n = 0; n < 256; n++) {
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c = (u_int32_t)n;
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for (k = 0; k < 8; k++) {
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if (c & 1)
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c = 0xedb88320UL ^ (c >> 1);
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else
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c = c >> 1;
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}
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ieee80211_crc_table[n] = c;
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}
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}
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/*
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* Update a running CRC with the bytes buf[0..len-1]--the CRC
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* should be initialized to all 1's, and the transmitted value
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* is the 1's complement of the final running CRC
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*/
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static u_int32_t
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ieee80211_crc_update(u_int32_t crc, u_int8_t *buf, int len)
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{
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u_int8_t *endbuf;
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for (endbuf = buf + len; buf < endbuf; buf++)
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crc = ieee80211_crc_table[(crc ^ *buf) & 0xff] ^ (crc >> 8);
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return crc;
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}
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