448 lines
13 KiB
C
448 lines
13 KiB
C
/******************************************************************************
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Copyright(c) 2003 - 2004 Intel Corporation. All rights reserved.
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This program is free software; you can redistribute it and/or modify it
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under the terms of version 2 of the GNU General Public License as
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published by the Free Software Foundation.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59
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Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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The full GNU General Public License is included in this distribution in the
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file called LICENSE.
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Contact Information:
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James P. Ketrenos <ipw2100-admin@linux.intel.com>
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Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
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******************************************************************************/
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#include <linux/compiler.h>
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/if_arp.h>
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#include <linux/in6.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/proc_fs.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/tcp.h>
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#include <linux/types.h>
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#include <linux/version.h>
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#include <linux/wireless.h>
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#include <linux/etherdevice.h>
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#include <asm/uaccess.h>
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#include <net/ieee80211.h>
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/*
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802.11 Data Frame
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,-------------------------------------------------------------------.
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Bytes | 2 | 2 | 6 | 6 | 6 | 2 | 0..2312 | 4 |
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|------|------|---------|---------|---------|------|---------|------|
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Desc. | ctrl | dura | DA/RA | TA | SA | Sequ | Frame | fcs |
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| | tion | (BSSID) | | | ence | data | |
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`--------------------------------------------------| |------'
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Total: 28 non-data bytes `----.----'
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.- 'Frame data' expands to <---------------------------'
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V
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,---------------------------------------------------.
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Bytes | 1 | 1 | 1 | 3 | 2 | 0-2304 |
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|------|------|---------|----------|------|---------|
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Desc. | SNAP | SNAP | Control |Eth Tunnel| Type | IP |
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| DSAP | SSAP | | | | Packet |
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| 0xAA | 0xAA |0x03 (UI)|0x00-00-F8| | |
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`-----------------------------------------| |
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Total: 8 non-data bytes `----.----'
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.- 'IP Packet' expands, if WEP enabled, to <--'
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V
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,-----------------------.
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Bytes | 4 | 0-2296 | 4 |
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|-----|-----------|-----|
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Desc. | IV | Encrypted | ICV |
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| | IP Packet | |
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`-----------------------'
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Total: 8 non-data bytes
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802.3 Ethernet Data Frame
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,-----------------------------------------.
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Bytes | 6 | 6 | 2 | Variable | 4 |
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|-------|-------|------|-----------|------|
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Desc. | Dest. | Source| Type | IP Packet | fcs |
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| MAC | MAC | | | |
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`-----------------------------------------'
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Total: 18 non-data bytes
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In the event that fragmentation is required, the incoming payload is split into
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N parts of size ieee->fts. The first fragment contains the SNAP header and the
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remaining packets are just data.
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If encryption is enabled, each fragment payload size is reduced by enough space
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to add the prefix and postfix (IV and ICV totalling 8 bytes in the case of WEP)
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So if you have 1500 bytes of payload with ieee->fts set to 500 without
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encryption it will take 3 frames. With WEP it will take 4 frames as the
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payload of each frame is reduced to 492 bytes.
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* SKB visualization
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*
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* ,- skb->data
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* |
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* | ETHERNET HEADER ,-<-- PAYLOAD
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* | | 14 bytes from skb->data
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* | 2 bytes for Type --> ,T. | (sizeof ethhdr)
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* | | | |
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* |,-Dest.--. ,--Src.---. | | |
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* | 6 bytes| | 6 bytes | | | |
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* v | | | | | |
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* 0 | v 1 | v | v 2
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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* ^ | ^ | ^ |
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* | | | | | |
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* | | | | `T' <---- 2 bytes for Type
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* | | | |
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* | | '---SNAP--' <-------- 6 bytes for SNAP
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* | |
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* `-IV--' <-------------------- 4 bytes for IV (WEP)
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*
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* SNAP HEADER
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*
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*/
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static u8 P802_1H_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0xf8 };
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static u8 RFC1042_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0x00 };
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static inline int ieee80211_put_snap(u8 *data, u16 h_proto)
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{
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struct ieee80211_snap_hdr *snap;
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u8 *oui;
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snap = (struct ieee80211_snap_hdr *)data;
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snap->dsap = 0xaa;
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snap->ssap = 0xaa;
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snap->ctrl = 0x03;
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if (h_proto == 0x8137 || h_proto == 0x80f3)
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oui = P802_1H_OUI;
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else
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oui = RFC1042_OUI;
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snap->oui[0] = oui[0];
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snap->oui[1] = oui[1];
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snap->oui[2] = oui[2];
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*(u16 *)(data + SNAP_SIZE) = htons(h_proto);
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return SNAP_SIZE + sizeof(u16);
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}
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static inline int ieee80211_encrypt_fragment(
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struct ieee80211_device *ieee,
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struct sk_buff *frag,
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int hdr_len)
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{
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struct ieee80211_crypt_data* crypt = ieee->crypt[ieee->tx_keyidx];
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int res;
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#ifdef CONFIG_IEEE80211_CRYPT_TKIP
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struct ieee80211_hdr *header;
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if (ieee->tkip_countermeasures &&
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crypt && crypt->ops && strcmp(crypt->ops->name, "TKIP") == 0) {
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header = (struct ieee80211_hdr *) frag->data;
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if (net_ratelimit()) {
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printk(KERN_DEBUG "%s: TKIP countermeasures: dropped "
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"TX packet to " MAC_FMT "\n",
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ieee->dev->name, MAC_ARG(header->addr1));
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}
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return -1;
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}
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#endif
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/* To encrypt, frame format is:
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* IV (4 bytes), clear payload (including SNAP), ICV (4 bytes) */
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// PR: FIXME: Copied from hostap. Check fragmentation/MSDU/MPDU encryption.
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/* Host-based IEEE 802.11 fragmentation for TX is not yet supported, so
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* call both MSDU and MPDU encryption functions from here. */
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atomic_inc(&crypt->refcnt);
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res = 0;
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if (crypt->ops->encrypt_msdu)
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res = crypt->ops->encrypt_msdu(frag, hdr_len, crypt->priv);
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if (res == 0 && crypt->ops->encrypt_mpdu)
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res = crypt->ops->encrypt_mpdu(frag, hdr_len, crypt->priv);
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atomic_dec(&crypt->refcnt);
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if (res < 0) {
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printk(KERN_INFO "%s: Encryption failed: len=%d.\n",
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ieee->dev->name, frag->len);
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ieee->ieee_stats.tx_discards++;
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return -1;
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}
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return 0;
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}
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void ieee80211_txb_free(struct ieee80211_txb *txb) {
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int i;
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if (unlikely(!txb))
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return;
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for (i = 0; i < txb->nr_frags; i++)
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if (txb->fragments[i])
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dev_kfree_skb_any(txb->fragments[i]);
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kfree(txb);
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}
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static struct ieee80211_txb *ieee80211_alloc_txb(int nr_frags, int txb_size,
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int gfp_mask)
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{
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struct ieee80211_txb *txb;
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int i;
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txb = kmalloc(
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sizeof(struct ieee80211_txb) + (sizeof(u8*) * nr_frags),
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gfp_mask);
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if (!txb)
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return NULL;
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memset(txb, 0, sizeof(struct ieee80211_txb));
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txb->nr_frags = nr_frags;
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txb->frag_size = txb_size;
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for (i = 0; i < nr_frags; i++) {
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txb->fragments[i] = dev_alloc_skb(txb_size);
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if (unlikely(!txb->fragments[i])) {
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i--;
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break;
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}
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}
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if (unlikely(i != nr_frags)) {
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while (i >= 0)
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dev_kfree_skb_any(txb->fragments[i--]);
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kfree(txb);
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return NULL;
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}
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return txb;
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}
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/* SKBs are added to the ieee->tx_queue. */
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int ieee80211_xmit(struct sk_buff *skb,
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struct net_device *dev)
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{
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struct ieee80211_device *ieee = netdev_priv(dev);
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struct ieee80211_txb *txb = NULL;
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struct ieee80211_hdr *frag_hdr;
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int i, bytes_per_frag, nr_frags, bytes_last_frag, frag_size;
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unsigned long flags;
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struct net_device_stats *stats = &ieee->stats;
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int ether_type, encrypt;
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int bytes, fc, hdr_len;
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struct sk_buff *skb_frag;
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struct ieee80211_hdr header = { /* Ensure zero initialized */
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.duration_id = 0,
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.seq_ctl = 0
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};
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u8 dest[ETH_ALEN], src[ETH_ALEN];
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struct ieee80211_crypt_data* crypt;
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spin_lock_irqsave(&ieee->lock, flags);
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/* If there is no driver handler to take the TXB, dont' bother
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* creating it... */
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if (!ieee->hard_start_xmit) {
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printk(KERN_WARNING "%s: No xmit handler.\n",
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ieee->dev->name);
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goto success;
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}
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if (unlikely(skb->len < SNAP_SIZE + sizeof(u16))) {
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printk(KERN_WARNING "%s: skb too small (%d).\n",
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ieee->dev->name, skb->len);
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goto success;
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}
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ether_type = ntohs(((struct ethhdr *)skb->data)->h_proto);
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crypt = ieee->crypt[ieee->tx_keyidx];
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encrypt = !(ether_type == ETH_P_PAE && ieee->ieee802_1x) &&
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ieee->host_encrypt && crypt && crypt->ops;
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if (!encrypt && ieee->ieee802_1x &&
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ieee->drop_unencrypted && ether_type != ETH_P_PAE) {
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stats->tx_dropped++;
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goto success;
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}
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#ifdef CONFIG_IEEE80211_DEBUG
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if (crypt && !encrypt && ether_type == ETH_P_PAE) {
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struct eapol *eap = (struct eapol *)(skb->data +
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sizeof(struct ethhdr) - SNAP_SIZE - sizeof(u16));
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IEEE80211_DEBUG_EAP("TX: IEEE 802.11 EAPOL frame: %s\n",
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eap_get_type(eap->type));
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}
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#endif
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/* Save source and destination addresses */
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memcpy(&dest, skb->data, ETH_ALEN);
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memcpy(&src, skb->data+ETH_ALEN, ETH_ALEN);
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/* Advance the SKB to the start of the payload */
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skb_pull(skb, sizeof(struct ethhdr));
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/* Determine total amount of storage required for TXB packets */
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bytes = skb->len + SNAP_SIZE + sizeof(u16);
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if (encrypt)
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fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA |
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IEEE80211_FCTL_WEP;
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else
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fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
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if (ieee->iw_mode == IW_MODE_INFRA) {
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fc |= IEEE80211_FCTL_TODS;
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/* To DS: Addr1 = BSSID, Addr2 = SA,
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Addr3 = DA */
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memcpy(&header.addr1, ieee->bssid, ETH_ALEN);
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memcpy(&header.addr2, &src, ETH_ALEN);
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memcpy(&header.addr3, &dest, ETH_ALEN);
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} else if (ieee->iw_mode == IW_MODE_ADHOC) {
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/* not From/To DS: Addr1 = DA, Addr2 = SA,
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Addr3 = BSSID */
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memcpy(&header.addr1, dest, ETH_ALEN);
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memcpy(&header.addr2, src, ETH_ALEN);
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memcpy(&header.addr3, ieee->bssid, ETH_ALEN);
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}
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header.frame_ctl = cpu_to_le16(fc);
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hdr_len = IEEE80211_3ADDR_LEN;
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/* Determine fragmentation size based on destination (multicast
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* and broadcast are not fragmented) */
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if (is_multicast_ether_addr(dest) ||
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is_broadcast_ether_addr(dest))
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frag_size = MAX_FRAG_THRESHOLD;
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else
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frag_size = ieee->fts;
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/* Determine amount of payload per fragment. Regardless of if
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* this stack is providing the full 802.11 header, one will
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* eventually be affixed to this fragment -- so we must account for
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* it when determining the amount of payload space. */
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bytes_per_frag = frag_size - IEEE80211_3ADDR_LEN;
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if (ieee->config &
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(CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
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bytes_per_frag -= IEEE80211_FCS_LEN;
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/* Each fragment may need to have room for encryptiong pre/postfix */
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if (encrypt)
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bytes_per_frag -= crypt->ops->extra_prefix_len +
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crypt->ops->extra_postfix_len;
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/* Number of fragments is the total bytes_per_frag /
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* payload_per_fragment */
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nr_frags = bytes / bytes_per_frag;
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bytes_last_frag = bytes % bytes_per_frag;
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if (bytes_last_frag)
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nr_frags++;
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else
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bytes_last_frag = bytes_per_frag;
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/* When we allocate the TXB we allocate enough space for the reserve
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* and full fragment bytes (bytes_per_frag doesn't include prefix,
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* postfix, header, FCS, etc.) */
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txb = ieee80211_alloc_txb(nr_frags, frag_size, GFP_ATOMIC);
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if (unlikely(!txb)) {
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printk(KERN_WARNING "%s: Could not allocate TXB\n",
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ieee->dev->name);
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goto failed;
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}
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txb->encrypted = encrypt;
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txb->payload_size = bytes;
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for (i = 0; i < nr_frags; i++) {
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skb_frag = txb->fragments[i];
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if (encrypt)
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skb_reserve(skb_frag, crypt->ops->extra_prefix_len);
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frag_hdr = (struct ieee80211_hdr *)skb_put(skb_frag, hdr_len);
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memcpy(frag_hdr, &header, hdr_len);
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/* If this is not the last fragment, then add the MOREFRAGS
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* bit to the frame control */
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if (i != nr_frags - 1) {
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frag_hdr->frame_ctl = cpu_to_le16(
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fc | IEEE80211_FCTL_MOREFRAGS);
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bytes = bytes_per_frag;
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} else {
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/* The last fragment takes the remaining length */
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bytes = bytes_last_frag;
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}
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/* Put a SNAP header on the first fragment */
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if (i == 0) {
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ieee80211_put_snap(
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skb_put(skb_frag, SNAP_SIZE + sizeof(u16)),
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ether_type);
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bytes -= SNAP_SIZE + sizeof(u16);
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}
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memcpy(skb_put(skb_frag, bytes), skb->data, bytes);
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/* Advance the SKB... */
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skb_pull(skb, bytes);
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/* Encryption routine will move the header forward in order
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* to insert the IV between the header and the payload */
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if (encrypt)
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ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len);
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if (ieee->config &
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(CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
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skb_put(skb_frag, 4);
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}
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success:
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spin_unlock_irqrestore(&ieee->lock, flags);
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dev_kfree_skb_any(skb);
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if (txb) {
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if ((*ieee->hard_start_xmit)(txb, dev) == 0) {
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stats->tx_packets++;
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stats->tx_bytes += txb->payload_size;
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return 0;
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}
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ieee80211_txb_free(txb);
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}
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return 0;
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failed:
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spin_unlock_irqrestore(&ieee->lock, flags);
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netif_stop_queue(dev);
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stats->tx_errors++;
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return 1;
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}
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EXPORT_SYMBOL(ieee80211_txb_free);
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