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d4e46a3d98
linux/net/mac80211/tx.c
Johannes Berg d4e46a3d98 [MAC80211]: fix race conditions with keys 
During receive processing, we select the key long before using it and
because there's no locking it is possible that we kfree() the key
after having selected it but before using it for crypto operations.
Obviously, this is bad.

Secondly, during transmit processing, there are two possible races: We
have a similar race between select_key() and using it for encryption,
but we also have a race here between select_key() and hardware
encryption (both when a key is removed.)

This patch solves these issues by using RCU: when a key is to be freed,
we first remove the pointer from the appropriate places (sdata->keys,
sdata->default_key, sta->key) using rcu_assign_pointer() and then
synchronize_rcu(). Then, we can safely kfree() the key and remove it
from the hardware. There's a window here where the hardware may still
be using it for decryption, but we can't work around that without having
two hardware callbacks, one to disable the key for RX and one to disable
it for TX; but the worst thing that will happen is that we receive a
packet decrypted that we don't find a key for any more and then drop it.

When we add a key, we first need to upload it to the hardware and then,
using rcu_assign_pointer() again, link it into our structures.

In the code using keys (TX/RX paths) we use rcu_dereference() to get the
key and enclose the whole tx/rx section in a rcu_read_lock() ...
rcu_read_unlock() block. Because we've uploaded the key to hardware
before linking it into internal structures, we can guarantee that it is
valid once get to into tx().

One possible race condition remains, however: when we have hardware
acceleration enabled and the driver shuts down the queues, we end up
queueing the frame. If now somebody removes the key, the key will be
removed from hwaccel and then then driver will be asked to encrypt the
frame with a key index that has been removed. Hence, drivers will need
to be aware that the hw_key_index they are passed might not be under
all circumstances. Most drivers will, however, simply ignore that
condition and encrypt the frame with the selected key anyway, this
only results in a frame being encrypted with a wrong key or dropped
(rightfully) because the key was not valid. There isn't much we can
do about it unless we want to walk the pending frame queue every time
a key is removed and remove all frames that used it.

This race condition, however, will most likely be solved once we add
multiqueue support to mac80211 because then frames will be queued
further up the stack instead of after being processed.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:49:26 -07:00

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/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*
* Transmit and frame generation functions.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/bitmap.h>
#include <linux/rcupdate.h>
#include <net/net_namespace.h>
#include <net/ieee80211_radiotap.h>
#include <net/cfg80211.h>
#include <net/mac80211.h>
#include <asm/unaligned.h>
#include "ieee80211_i.h"
#include "ieee80211_led.h"
#include "wep.h"
#include "wpa.h"
#include "wme.h"
#include "ieee80211_rate.h"
#define IEEE80211_TX_OK 0
#define IEEE80211_TX_AGAIN 1
#define IEEE80211_TX_FRAG_AGAIN 2
/* misc utils */
static inline void ieee80211_include_sequence(struct ieee80211_sub_if_data *sdata,
struct ieee80211_hdr *hdr)
{
/* Set the sequence number for this frame. */
hdr->seq_ctrl = cpu_to_le16(sdata->sequence);
/* Increase the sequence number. */
sdata->sequence = (sdata->sequence + 0x10) & IEEE80211_SCTL_SEQ;
}
#ifdef CONFIG_MAC80211_LOWTX_FRAME_DUMP
static void ieee80211_dump_frame(const char *ifname, const char *title,
const struct sk_buff *skb)
{
const struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
u16 fc;
int hdrlen;
printk(KERN_DEBUG "%s: %s (len=%d)", ifname, title, skb->len);
if (skb->len < 4) {
printk("\n");
return;
}
fc = le16_to_cpu(hdr->frame_control);
hdrlen = ieee80211_get_hdrlen(fc);
if (hdrlen > skb->len)
hdrlen = skb->len;
if (hdrlen >= 4)
printk(" FC=0x%04x DUR=0x%04x",
fc, le16_to_cpu(hdr->duration_id));
if (hdrlen >= 10)
printk(" A1=" MAC_FMT, MAC_ARG(hdr->addr1));
if (hdrlen >= 16)
printk(" A2=" MAC_FMT, MAC_ARG(hdr->addr2));
if (hdrlen >= 24)
printk(" A3=" MAC_FMT, MAC_ARG(hdr->addr3));
if (hdrlen >= 30)
printk(" A4=" MAC_FMT, MAC_ARG(hdr->addr4));
printk("\n");
}
#else /* CONFIG_MAC80211_LOWTX_FRAME_DUMP */
static inline void ieee80211_dump_frame(const char *ifname, const char *title,
struct sk_buff *skb)
{
}
#endif /* CONFIG_MAC80211_LOWTX_FRAME_DUMP */
static u16 ieee80211_duration(struct ieee80211_txrx_data *tx, int group_addr,
int next_frag_len)
{
int rate, mrate, erp, dur, i;
struct ieee80211_rate *txrate = tx->u.tx.rate;
struct ieee80211_local *local = tx->local;
struct ieee80211_hw_mode *mode = tx->u.tx.mode;
erp = txrate->flags & IEEE80211_RATE_ERP;
/*
* data and mgmt (except PS Poll):
* - during CFP: 32768
* - during contention period:
* if addr1 is group address: 0
* if more fragments = 0 and addr1 is individual address: time to
* transmit one ACK plus SIFS
* if more fragments = 1 and addr1 is individual address: time to
* transmit next fragment plus 2 x ACK plus 3 x SIFS
*
* IEEE 802.11, 9.6:
* - control response frame (CTS or ACK) shall be transmitted using the
* same rate as the immediately previous frame in the frame exchange
* sequence, if this rate belongs to the PHY mandatory rates, or else
* at the highest possible rate belonging to the PHY rates in the
* BSSBasicRateSet
*/
if ((tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_CTL) {
/* TODO: These control frames are not currently sent by
* 80211.o, but should they be implemented, this function
* needs to be updated to support duration field calculation.
*
* RTS: time needed to transmit pending data/mgmt frame plus
* one CTS frame plus one ACK frame plus 3 x SIFS
* CTS: duration of immediately previous RTS minus time
* required to transmit CTS and its SIFS
* ACK: 0 if immediately previous directed data/mgmt had
* more=0, with more=1 duration in ACK frame is duration
* from previous frame minus time needed to transmit ACK
* and its SIFS
* PS Poll: BIT(15) | BIT(14) | aid
*/
return 0;
}
/* data/mgmt */
if (0 /* FIX: data/mgmt during CFP */)
return 32768;
if (group_addr) /* Group address as the destination - no ACK */
return 0;
/* Individual destination address:
* IEEE 802.11, Ch. 9.6 (after IEEE 802.11g changes)
* CTS and ACK frames shall be transmitted using the highest rate in
* basic rate set that is less than or equal to the rate of the
* immediately previous frame and that is using the same modulation
* (CCK or OFDM). If no basic rate set matches with these requirements,
* the highest mandatory rate of the PHY that is less than or equal to
* the rate of the previous frame is used.
* Mandatory rates for IEEE 802.11g PHY: 1, 2, 5.5, 11, 6, 12, 24 Mbps
*/
rate = -1;
mrate = 10; /* use 1 Mbps if everything fails */
for (i = 0; i < mode->num_rates; i++) {
struct ieee80211_rate *r = &mode->rates[i];
if (r->rate > txrate->rate)
break;
if (IEEE80211_RATE_MODULATION(txrate->flags) !=
IEEE80211_RATE_MODULATION(r->flags))
continue;
if (r->flags & IEEE80211_RATE_BASIC)
rate = r->rate;
else if (r->flags & IEEE80211_RATE_MANDATORY)
mrate = r->rate;
}
if (rate == -1) {
/* No matching basic rate found; use highest suitable mandatory
* PHY rate */
rate = mrate;
}
/* Time needed to transmit ACK
* (10 bytes + 4-byte FCS = 112 bits) plus SIFS; rounded up
* to closest integer */
dur = ieee80211_frame_duration(local, 10, rate, erp,
tx->sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
if (next_frag_len) {
/* Frame is fragmented: duration increases with time needed to
* transmit next fragment plus ACK and 2 x SIFS. */
dur *= 2; /* ACK + SIFS */
/* next fragment */
dur += ieee80211_frame_duration(local, next_frag_len,
txrate->rate, erp,
tx->sdata->flags &
IEEE80211_SDATA_SHORT_PREAMBLE);
}
return dur;
}
static inline int __ieee80211_queue_stopped(const struct ieee80211_local *local,
int queue)
{
return test_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
}
static inline int __ieee80211_queue_pending(const struct ieee80211_local *local,
int queue)
{
return test_bit(IEEE80211_LINK_STATE_PENDING, &local->state[queue]);
}
static int inline is_ieee80211_device(struct net_device *dev,
struct net_device *master)
{
return (wdev_priv(dev->ieee80211_ptr) ==
wdev_priv(master->ieee80211_ptr));
}
/* tx handlers */
static ieee80211_txrx_result
ieee80211_tx_h_check_assoc(struct ieee80211_txrx_data *tx)
{
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
struct sk_buff *skb = tx->skb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
u32 sta_flags;
if (unlikely(tx->local->sta_scanning != 0) &&
((tx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_MGMT ||
(tx->fc & IEEE80211_FCTL_STYPE) != IEEE80211_STYPE_PROBE_REQ))
return TXRX_DROP;
if (tx->flags & IEEE80211_TXRXD_TXPS_BUFFERED)
return TXRX_CONTINUE;
sta_flags = tx->sta ? tx->sta->flags : 0;
if (likely(tx->flags & IEEE80211_TXRXD_TXUNICAST)) {
if (unlikely(!(sta_flags & WLAN_STA_ASSOC) &&
tx->sdata->type != IEEE80211_IF_TYPE_IBSS &&
(tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA)) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: dropped data frame to not "
"associated station " MAC_FMT "\n",
tx->dev->name, MAC_ARG(hdr->addr1));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
I802_DEBUG_INC(tx->local->tx_handlers_drop_not_assoc);
return TXRX_DROP;
}
} else {
if (unlikely((tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA &&
tx->local->num_sta == 0 &&
tx->sdata->type != IEEE80211_IF_TYPE_IBSS)) {
/*
* No associated STAs - no need to send multicast
* frames.
*/
return TXRX_DROP;
}
return TXRX_CONTINUE;
}
if (unlikely(!tx->u.tx.mgmt_interface && tx->sdata->ieee802_1x &&
!(sta_flags & WLAN_STA_AUTHORIZED))) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: dropped frame to " MAC_FMT
" (unauthorized port)\n", tx->dev->name,
MAC_ARG(hdr->addr1));
#endif
I802_DEBUG_INC(tx->local->tx_handlers_drop_unauth_port);
return TXRX_DROP;
}
return TXRX_CONTINUE;
}
static ieee80211_txrx_result
ieee80211_tx_h_sequence(struct ieee80211_txrx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
if (ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control)) >= 24)
ieee80211_include_sequence(tx->sdata, hdr);
return TXRX_CONTINUE;
}
/* This function is called whenever the AP is about to exceed the maximum limit
* of buffered frames for power saving STAs. This situation should not really
* happen often during normal operation, so dropping the oldest buffered packet
* from each queue should be OK to make some room for new frames. */
static void purge_old_ps_buffers(struct ieee80211_local *local)
{
int total = 0, purged = 0;
struct sk_buff *skb;
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
read_lock(&local->sub_if_lock);
list_for_each_entry(sdata, &local->sub_if_list, list) {
struct ieee80211_if_ap *ap;
if (sdata->dev == local->mdev ||
sdata->type != IEEE80211_IF_TYPE_AP)
continue;
ap = &sdata->u.ap;
skb = skb_dequeue(&ap->ps_bc_buf);
if (skb) {
purged++;
dev_kfree_skb(skb);
}
total += skb_queue_len(&ap->ps_bc_buf);
}
read_unlock(&local->sub_if_lock);
read_lock_bh(&local->sta_lock);
list_for_each_entry(sta, &local->sta_list, list) {
skb = skb_dequeue(&sta->ps_tx_buf);
if (skb) {
purged++;
dev_kfree_skb(skb);
}
total += skb_queue_len(&sta->ps_tx_buf);
}
read_unlock_bh(&local->sta_lock);
local->total_ps_buffered = total;
printk(KERN_DEBUG "%s: PS buffers full - purged %d frames\n",
local->mdev->name, purged);
}
static inline ieee80211_txrx_result
ieee80211_tx_h_multicast_ps_buf(struct ieee80211_txrx_data *tx)
{
/* broadcast/multicast frame */
/* If any of the associated stations is in power save mode,
* the frame is buffered to be sent after DTIM beacon frame */
if ((tx->local->hw.flags & IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING) &&
tx->sdata->type != IEEE80211_IF_TYPE_WDS &&
tx->sdata->bss && atomic_read(&tx->sdata->bss->num_sta_ps) &&
!(tx->fc & IEEE80211_FCTL_ORDER)) {
if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
purge_old_ps_buffers(tx->local);
if (skb_queue_len(&tx->sdata->bss->ps_bc_buf) >=
AP_MAX_BC_BUFFER) {
if (net_ratelimit()) {
printk(KERN_DEBUG "%s: BC TX buffer full - "
"dropping the oldest frame\n",
tx->dev->name);
}
dev_kfree_skb(skb_dequeue(&tx->sdata->bss->ps_bc_buf));
} else
tx->local->total_ps_buffered++;
skb_queue_tail(&tx->sdata->bss->ps_bc_buf, tx->skb);
return TXRX_QUEUED;
}
return TXRX_CONTINUE;
}
static inline ieee80211_txrx_result
ieee80211_tx_h_unicast_ps_buf(struct ieee80211_txrx_data *tx)
{
struct sta_info *sta = tx->sta;
if (unlikely(!sta ||
((tx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_MGMT &&
(tx->fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PROBE_RESP)))
return TXRX_CONTINUE;
if (unlikely((sta->flags & WLAN_STA_PS) && !sta->pspoll)) {
struct ieee80211_tx_packet_data *pkt_data;
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "STA " MAC_FMT " aid %d: PS buffer (entries "
"before %d)\n",
MAC_ARG(sta->addr), sta->aid,
skb_queue_len(&sta->ps_tx_buf));
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
sta->flags |= WLAN_STA_TIM;
if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
purge_old_ps_buffers(tx->local);
if (skb_queue_len(&sta->ps_tx_buf) >= STA_MAX_TX_BUFFER) {
struct sk_buff *old = skb_dequeue(&sta->ps_tx_buf);
if (net_ratelimit()) {
printk(KERN_DEBUG "%s: STA " MAC_FMT " TX "
"buffer full - dropping oldest frame\n",
tx->dev->name, MAC_ARG(sta->addr));
}
dev_kfree_skb(old);
} else
tx->local->total_ps_buffered++;
/* Queue frame to be sent after STA sends an PS Poll frame */
if (skb_queue_empty(&sta->ps_tx_buf)) {
if (tx->local->ops->set_tim)
tx->local->ops->set_tim(local_to_hw(tx->local),
sta->aid, 1);
if (tx->sdata->bss)
bss_tim_set(tx->local, tx->sdata->bss, sta->aid);
}
pkt_data = (struct ieee80211_tx_packet_data *)tx->skb->cb;
pkt_data->jiffies = jiffies;
skb_queue_tail(&sta->ps_tx_buf, tx->skb);
return TXRX_QUEUED;
}
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
else if (unlikely(sta->flags & WLAN_STA_PS)) {
printk(KERN_DEBUG "%s: STA " MAC_FMT " in PS mode, but pspoll "
"set -> send frame\n", tx->dev->name,
MAC_ARG(sta->addr));
}
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
sta->pspoll = 0;
return TXRX_CONTINUE;
}
static ieee80211_txrx_result
ieee80211_tx_h_ps_buf(struct ieee80211_txrx_data *tx)
{
if (unlikely(tx->flags & IEEE80211_TXRXD_TXPS_BUFFERED))
return TXRX_CONTINUE;
if (tx->flags & IEEE80211_TXRXD_TXUNICAST)
return ieee80211_tx_h_unicast_ps_buf(tx);
else
return ieee80211_tx_h_multicast_ps_buf(tx);
}
static ieee80211_txrx_result
ieee80211_tx_h_select_key(struct ieee80211_txrx_data *tx)
{
struct ieee80211_key *key;
tx->u.tx.control->key_idx = HW_KEY_IDX_INVALID;
if (unlikely(tx->u.tx.control->flags & IEEE80211_TXCTL_DO_NOT_ENCRYPT))
tx->key = NULL;
else if (tx->sta && (key = rcu_dereference(tx->sta->key)))
tx->key = key;
else if ((key = rcu_dereference(tx->sdata->default_key)))
tx->key = key;
else if (tx->sdata->drop_unencrypted &&
!(tx->sdata->eapol && ieee80211_is_eapol(tx->skb))) {
I802_DEBUG_INC(tx->local->tx_handlers_drop_unencrypted);
return TXRX_DROP;
} else
tx->key = NULL;
if (tx->key) {
tx->key->tx_rx_count++;
if (unlikely(tx->local->key_tx_rx_threshold &&
tx->key->tx_rx_count >
tx->local->key_tx_rx_threshold)) {
ieee80211_key_threshold_notify(tx->dev, tx->key,
tx->sta);
}
}
return TXRX_CONTINUE;
}
static ieee80211_txrx_result
ieee80211_tx_h_fragment(struct ieee80211_txrx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
size_t hdrlen, per_fragm, num_fragm, payload_len, left;
struct sk_buff **frags, *first, *frag;
int i;
u16 seq;
u8 *pos;
int frag_threshold = tx->local->fragmentation_threshold;
if (!(tx->flags & IEEE80211_TXRXD_FRAGMENTED))
return TXRX_CONTINUE;
first = tx->skb;
hdrlen = ieee80211_get_hdrlen(tx->fc);
payload_len = first->len - hdrlen;
per_fragm = frag_threshold - hdrlen - FCS_LEN;
num_fragm = DIV_ROUND_UP(payload_len, per_fragm);
frags = kzalloc(num_fragm * sizeof(struct sk_buff *), GFP_ATOMIC);
if (!frags)
goto fail;
hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREFRAGS);
seq = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_SEQ;
pos = first->data + hdrlen + per_fragm;
left = payload_len - per_fragm;
for (i = 0; i < num_fragm - 1; i++) {
struct ieee80211_hdr *fhdr;
size_t copylen;
if (left <= 0)
goto fail;
/* reserve enough extra head and tail room for possible
* encryption */
frag = frags[i] =
dev_alloc_skb(tx->local->tx_headroom +
frag_threshold +
IEEE80211_ENCRYPT_HEADROOM +
IEEE80211_ENCRYPT_TAILROOM);
if (!frag)
goto fail;
/* Make sure that all fragments use the same priority so
* that they end up using the same TX queue */
frag->priority = first->priority;
skb_reserve(frag, tx->local->tx_headroom +
IEEE80211_ENCRYPT_HEADROOM);
fhdr = (struct ieee80211_hdr *) skb_put(frag, hdrlen);
memcpy(fhdr, first->data, hdrlen);
if (i == num_fragm - 2)
fhdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_MOREFRAGS);
fhdr->seq_ctrl = cpu_to_le16(seq | ((i + 1) & IEEE80211_SCTL_FRAG));
copylen = left > per_fragm ? per_fragm : left;
memcpy(skb_put(frag, copylen), pos, copylen);
pos += copylen;
left -= copylen;
}
skb_trim(first, hdrlen + per_fragm);
tx->u.tx.num_extra_frag = num_fragm - 1;
tx->u.tx.extra_frag = frags;
return TXRX_CONTINUE;
fail:
printk(KERN_DEBUG "%s: failed to fragment frame\n", tx->dev->name);
if (frags) {
for (i = 0; i < num_fragm - 1; i++)
if (frags[i])
dev_kfree_skb(frags[i]);
kfree(frags);
}
I802_DEBUG_INC(tx->local->tx_handlers_drop_fragment);
return TXRX_DROP;
}
static int wep_encrypt_skb(struct ieee80211_txrx_data *tx, struct sk_buff *skb)
{
if (!(tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) {
if (ieee80211_wep_encrypt(tx->local, skb, tx->key))
return -1;
} else {
tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
if (tx->local->hw.flags & IEEE80211_HW_WEP_INCLUDE_IV) {
if (ieee80211_wep_add_iv(tx->local, skb, tx->key) ==
NULL)
return -1;
}
}
return 0;
}
static ieee80211_txrx_result
ieee80211_tx_h_wep_encrypt(struct ieee80211_txrx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
u16 fc;
fc = le16_to_cpu(hdr->frame_control);
if (!tx->key || tx->key->conf.alg != ALG_WEP ||
((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA &&
((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_MGMT ||
(fc & IEEE80211_FCTL_STYPE) != IEEE80211_STYPE_AUTH)))
return TXRX_CONTINUE;
tx->u.tx.control->iv_len = WEP_IV_LEN;
tx->u.tx.control->icv_len = WEP_ICV_LEN;
ieee80211_tx_set_iswep(tx);
if (wep_encrypt_skb(tx, tx->skb) < 0) {
I802_DEBUG_INC(tx->local->tx_handlers_drop_wep);
return TXRX_DROP;
}
if (tx->u.tx.extra_frag) {
int i;
for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
if (wep_encrypt_skb(tx, tx->u.tx.extra_frag[i]) < 0) {
I802_DEBUG_INC(tx->local->
tx_handlers_drop_wep);
return TXRX_DROP;
}
}
}
return TXRX_CONTINUE;
}
static ieee80211_txrx_result
ieee80211_tx_h_rate_ctrl(struct ieee80211_txrx_data *tx)
{
struct rate_control_extra extra;
memset(&extra, 0, sizeof(extra));
extra.mode = tx->u.tx.mode;
extra.mgmt_data = tx->sdata &&
tx->sdata->type == IEEE80211_IF_TYPE_MGMT;
extra.ethertype = tx->ethertype;
tx->u.tx.rate = rate_control_get_rate(tx->local, tx->dev, tx->skb,
&extra);
if (unlikely(extra.probe != NULL)) {
tx->u.tx.control->flags |= IEEE80211_TXCTL_RATE_CTRL_PROBE;
tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
tx->u.tx.control->alt_retry_rate = tx->u.tx.rate->val;
tx->u.tx.rate = extra.probe;
} else {
tx->u.tx.control->alt_retry_rate = -1;
}
if (!tx->u.tx.rate)
return TXRX_DROP;
if (tx->u.tx.mode->mode == MODE_IEEE80211G &&
(tx->sdata->flags & IEEE80211_SDATA_USE_PROTECTION) &&
(tx->flags & IEEE80211_TXRXD_FRAGMENTED) && extra.nonerp) {
tx->u.tx.last_frag_rate = tx->u.tx.rate;
if (extra.probe)
tx->flags &= ~IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
else
tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
tx->u.tx.rate = extra.nonerp;
tx->u.tx.control->rate = extra.nonerp;
tx->u.tx.control->flags &= ~IEEE80211_TXCTL_RATE_CTRL_PROBE;
} else {
tx->u.tx.last_frag_rate = tx->u.tx.rate;
tx->u.tx.control->rate = tx->u.tx.rate;
}
tx->u.tx.control->tx_rate = tx->u.tx.rate->val;
return TXRX_CONTINUE;
}
static ieee80211_txrx_result
ieee80211_tx_h_misc(struct ieee80211_txrx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
u16 fc = le16_to_cpu(hdr->frame_control);
u16 dur;
struct ieee80211_tx_control *control = tx->u.tx.control;
struct ieee80211_hw_mode *mode = tx->u.tx.mode;
if (!is_multicast_ether_addr(hdr->addr1)) {
if (tx->skb->len + FCS_LEN > tx->local->rts_threshold &&
tx->local->rts_threshold < IEEE80211_MAX_RTS_THRESHOLD) {
control->flags |= IEEE80211_TXCTL_USE_RTS_CTS;
control->flags |= IEEE80211_TXCTL_LONG_RETRY_LIMIT;
control->retry_limit =
tx->local->long_retry_limit;
} else {
control->retry_limit =
tx->local->short_retry_limit;
}
} else {
control->retry_limit = 1;
}
if (tx->flags & IEEE80211_TXRXD_FRAGMENTED) {
/* Do not use multiple retry rates when sending fragmented
* frames.
* TODO: The last fragment could still use multiple retry
* rates. */
control->alt_retry_rate = -1;
}
/* Use CTS protection for unicast frames sent using extended rates if
* there are associated non-ERP stations and RTS/CTS is not configured
* for the frame. */
if (mode->mode == MODE_IEEE80211G &&
(tx->u.tx.rate->flags & IEEE80211_RATE_ERP) &&
(tx->flags & IEEE80211_TXRXD_TXUNICAST) &&
(tx->sdata->flags & IEEE80211_SDATA_USE_PROTECTION) &&
!(control->flags & IEEE80211_TXCTL_USE_RTS_CTS))
control->flags |= IEEE80211_TXCTL_USE_CTS_PROTECT;
/* Transmit data frames using short preambles if the driver supports
* short preambles at the selected rate and short preambles are
* available on the network at the current point in time. */
if (((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA) &&
(tx->u.tx.rate->flags & IEEE80211_RATE_PREAMBLE2) &&
(tx->sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE) &&
(!tx->sta || (tx->sta->flags & WLAN_STA_SHORT_PREAMBLE))) {
tx->u.tx.control->tx_rate = tx->u.tx.rate->val2;
}
/* Setup duration field for the first fragment of the frame. Duration
* for remaining fragments will be updated when they are being sent
* to low-level driver in ieee80211_tx(). */
dur = ieee80211_duration(tx, is_multicast_ether_addr(hdr->addr1),
(tx->flags & IEEE80211_TXRXD_FRAGMENTED) ?
tx->u.tx.extra_frag[0]->len : 0);
hdr->duration_id = cpu_to_le16(dur);
if ((control->flags & IEEE80211_TXCTL_USE_RTS_CTS) ||
(control->flags & IEEE80211_TXCTL_USE_CTS_PROTECT)) {
struct ieee80211_rate *rate;
/* Do not use multiple retry rates when using RTS/CTS */
control->alt_retry_rate = -1;
/* Use min(data rate, max base rate) as CTS/RTS rate */
rate = tx->u.tx.rate;
while (rate > mode->rates &&
!(rate->flags & IEEE80211_RATE_BASIC))
rate--;
control->rts_cts_rate = rate->val;
control->rts_rate = rate;
}
if (tx->sta) {
tx->sta->tx_packets++;
tx->sta->tx_fragments++;
tx->sta->tx_bytes += tx->skb->len;
if (tx->u.tx.extra_frag) {
int i;
tx->sta->tx_fragments += tx->u.tx.num_extra_frag;
for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
tx->sta->tx_bytes +=
tx->u.tx.extra_frag[i]->len;
}
}
}
return TXRX_CONTINUE;
}
static ieee80211_txrx_result
ieee80211_tx_h_load_stats(struct ieee80211_txrx_data *tx)
{
struct ieee80211_local *local = tx->local;
struct ieee80211_hw_mode *mode = tx->u.tx.mode;
struct sk_buff *skb = tx->skb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
u32 load = 0, hdrtime;
/* TODO: this could be part of tx_status handling, so that the number
* of retries would be known; TX rate should in that case be stored
* somewhere with the packet */
/* Estimate total channel use caused by this frame */
/* 1 bit at 1 Mbit/s takes 1 usec; in channel_use values,
* 1 usec = 1/8 * (1080 / 10) = 13.5 */
if (mode->mode == MODE_IEEE80211A ||
mode->mode == MODE_ATHEROS_TURBO ||
mode->mode == MODE_ATHEROS_TURBOG ||
(mode->mode == MODE_IEEE80211G &&
tx->u.tx.rate->flags & IEEE80211_RATE_ERP))
hdrtime = CHAN_UTIL_HDR_SHORT;
else
hdrtime = CHAN_UTIL_HDR_LONG;
load = hdrtime;
if (!is_multicast_ether_addr(hdr->addr1))
load += hdrtime;
if (tx->u.tx.control->flags & IEEE80211_TXCTL_USE_RTS_CTS)
load += 2 * hdrtime;
else if (tx->u.tx.control->flags & IEEE80211_TXCTL_USE_CTS_PROTECT)
load += hdrtime;
load += skb->len * tx->u.tx.rate->rate_inv;
if (tx->u.tx.extra_frag) {
int i;
for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
load += 2 * hdrtime;
load += tx->u.tx.extra_frag[i]->len *
tx->u.tx.rate->rate;
}
}
/* Divide channel_use by 8 to avoid wrapping around the counter */
load >>= CHAN_UTIL_SHIFT;
local->channel_use_raw += load;
if (tx->sta)
tx->sta->channel_use_raw += load;
tx->sdata->channel_use_raw += load;
return TXRX_CONTINUE;
}
/* TODO: implement register/unregister functions for adding TX/RX handlers
* into ordered list */
ieee80211_tx_handler ieee80211_tx_handlers[] =
{
ieee80211_tx_h_check_assoc,
ieee80211_tx_h_sequence,
ieee80211_tx_h_ps_buf,
ieee80211_tx_h_select_key,
ieee80211_tx_h_michael_mic_add,
ieee80211_tx_h_fragment,
ieee80211_tx_h_tkip_encrypt,
ieee80211_tx_h_ccmp_encrypt,
ieee80211_tx_h_wep_encrypt,
ieee80211_tx_h_rate_ctrl,
ieee80211_tx_h_misc,
ieee80211_tx_h_load_stats,
NULL
};
/* actual transmit path */
/*
* deal with packet injection down monitor interface
* with Radiotap Header -- only called for monitor mode interface
*/
static ieee80211_txrx_result
__ieee80211_parse_tx_radiotap(
struct ieee80211_txrx_data *tx,
struct sk_buff *skb, struct ieee80211_tx_control *control)
{
/*
* this is the moment to interpret and discard the radiotap header that
* must be at the start of the packet injected in Monitor mode
*
* Need to take some care with endian-ness since radiotap
* args are little-endian
*/
struct ieee80211_radiotap_iterator iterator;
struct ieee80211_radiotap_header *rthdr =
(struct ieee80211_radiotap_header *) skb->data;
struct ieee80211_hw_mode *mode = tx->local->hw.conf.mode;
int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
/*
* default control situation for all injected packets
* FIXME: this does not suit all usage cases, expand to allow control
*/
control->retry_limit = 1; /* no retry */
control->key_idx = HW_KEY_IDX_INVALID;
control->flags &= ~(IEEE80211_TXCTL_USE_RTS_CTS |
IEEE80211_TXCTL_USE_CTS_PROTECT);
control->flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT |
IEEE80211_TXCTL_NO_ACK;
control->antenna_sel_tx = 0; /* default to default antenna */
/*
* for every radiotap entry that is present
* (ieee80211_radiotap_iterator_next returns -ENOENT when no more
* entries present, or -EINVAL on error)
*/
while (!ret) {
int i, target_rate;
ret = ieee80211_radiotap_iterator_next(&iterator);
if (ret)
continue;
/* see if this argument is something we can use */
switch (iterator.this_arg_index) {
/*
* You must take care when dereferencing iterator.this_arg
* for multibyte types... the pointer is not aligned. Use
* get_unaligned((type *)iterator.this_arg) to dereference
* iterator.this_arg for type "type" safely on all arches.
*/
case IEEE80211_RADIOTAP_RATE:
/*
* radiotap rate u8 is in 500kbps units eg, 0x02=1Mbps
* ieee80211 rate int is in 100kbps units eg, 0x0a=1Mbps
*/
target_rate = (*iterator.this_arg) * 5;
for (i = 0; i < mode->num_rates; i++) {
struct ieee80211_rate *r = &mode->rates[i];
if (r->rate > target_rate)
continue;
control->rate = r;
if (r->flags & IEEE80211_RATE_PREAMBLE2)
control->tx_rate = r->val2;
else
control->tx_rate = r->val;
/* end on exact match */
if (r->rate == target_rate)
i = mode->num_rates;
}
break;
case IEEE80211_RADIOTAP_ANTENNA:
/*
* radiotap uses 0 for 1st ant, mac80211 is 1 for
* 1st ant
*/
control->antenna_sel_tx = (*iterator.this_arg) + 1;
break;
case IEEE80211_RADIOTAP_DBM_TX_POWER:
control->power_level = *iterator.this_arg;
break;
case IEEE80211_RADIOTAP_FLAGS:
if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) {
/*
* this indicates that the skb we have been
* handed has the 32-bit FCS CRC at the end...
* we should react to that by snipping it off
* because it will be recomputed and added
* on transmission
*/
if (skb->len < (iterator.max_length + FCS_LEN))
return TXRX_DROP;
skb_trim(skb, skb->len - FCS_LEN);
}
break;
default:
break;
}
}
if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
return TXRX_DROP;
/*
* remove the radiotap header
* iterator->max_length was sanity-checked against
* skb->len by iterator init
*/
skb_pull(skb, iterator.max_length);
return TXRX_CONTINUE;
}
static ieee80211_txrx_result inline
__ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
struct sk_buff *skb,
struct net_device *dev,
struct ieee80211_tx_control *control)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_sub_if_data *sdata;
ieee80211_txrx_result res = TXRX_CONTINUE;
int hdrlen;
memset(tx, 0, sizeof(*tx));
tx->skb = skb;
tx->dev = dev; /* use original interface */
tx->local = local;
tx->sdata = IEEE80211_DEV_TO_SUB_IF(dev);
tx->sta = sta_info_get(local, hdr->addr1);
tx->fc = le16_to_cpu(hdr->frame_control);
/*
* set defaults for things that can be set by
* injected radiotap headers
*/
control->power_level = local->hw.conf.power_level;
control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
/* process and remove the injection radiotap header */
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
if (unlikely(sdata->type == IEEE80211_IF_TYPE_MNTR)) {
if (__ieee80211_parse_tx_radiotap(tx, skb, control) ==
TXRX_DROP) {
return TXRX_DROP;
}
/*
* we removed the radiotap header after this point,
* we filled control with what we could use
* set to the actual ieee header now
*/
hdr = (struct ieee80211_hdr *) skb->data;
res = TXRX_QUEUED; /* indication it was monitor packet */
}
tx->u.tx.control = control;
if (is_multicast_ether_addr(hdr->addr1)) {
tx->flags &= ~IEEE80211_TXRXD_TXUNICAST;
control->flags |= IEEE80211_TXCTL_NO_ACK;
} else {
tx->flags |= IEEE80211_TXRXD_TXUNICAST;
control->flags &= ~IEEE80211_TXCTL_NO_ACK;
}
if (local->fragmentation_threshold < IEEE80211_MAX_FRAG_THRESHOLD &&
(tx->flags & IEEE80211_TXRXD_TXUNICAST) &&
skb->len + FCS_LEN > local->fragmentation_threshold &&
!local->ops->set_frag_threshold)
tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
else
tx->flags &= ~IEEE80211_TXRXD_FRAGMENTED;
if (!tx->sta)
control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
else if (tx->sta->clear_dst_mask) {
control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
tx->sta->clear_dst_mask = 0;
}
hdrlen = ieee80211_get_hdrlen(tx->fc);
if (skb->len > hdrlen + sizeof(rfc1042_header) + 2) {
u8 *pos = &skb->data[hdrlen + sizeof(rfc1042_header)];
tx->ethertype = (pos[0] << 8) | pos[1];
}
control->flags |= IEEE80211_TXCTL_FIRST_FRAGMENT;
return res;
}
/* Device in tx->dev has a reference added; use dev_put(tx->dev) when
* finished with it. */
static int inline ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
struct sk_buff *skb,
struct net_device *mdev,
struct ieee80211_tx_control *control)
{
struct ieee80211_tx_packet_data *pkt_data;
struct net_device *dev;
pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
dev = dev_get_by_index(&init_net, pkt_data->ifindex);
if (unlikely(dev && !is_ieee80211_device(dev, mdev))) {
dev_put(dev);
dev = NULL;
}
if (unlikely(!dev))
return -ENODEV;
__ieee80211_tx_prepare(tx, skb, dev, control);
return 0;
}
static int __ieee80211_tx(struct ieee80211_local *local, struct sk_buff *skb,
struct ieee80211_txrx_data *tx)
{
struct ieee80211_tx_control *control = tx->u.tx.control;
int ret, i;
if (!ieee80211_qdisc_installed(local->mdev) &&
__ieee80211_queue_stopped(local, 0)) {
netif_stop_queue(local->mdev);
return IEEE80211_TX_AGAIN;
}
if (skb) {
ieee80211_dump_frame(local->mdev->name, "TX to low-level driver", skb);
ret = local->ops->tx(local_to_hw(local), skb, control);
if (ret)
return IEEE80211_TX_AGAIN;
local->mdev->trans_start = jiffies;
ieee80211_led_tx(local, 1);
}
if (tx->u.tx.extra_frag) {
control->flags &= ~(IEEE80211_TXCTL_USE_RTS_CTS |
IEEE80211_TXCTL_USE_CTS_PROTECT |
IEEE80211_TXCTL_CLEAR_DST_MASK |
IEEE80211_TXCTL_FIRST_FRAGMENT);
for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
if (!tx->u.tx.extra_frag[i])
continue;
if (__ieee80211_queue_stopped(local, control->queue))
return IEEE80211_TX_FRAG_AGAIN;
if (i == tx->u.tx.num_extra_frag) {
control->tx_rate = tx->u.tx.last_frag_hwrate;
control->rate = tx->u.tx.last_frag_rate;
if (tx->flags & IEEE80211_TXRXD_TXPROBE_LAST_FRAG)
control->flags |=
IEEE80211_TXCTL_RATE_CTRL_PROBE;
else
control->flags &=
~IEEE80211_TXCTL_RATE_CTRL_PROBE;
}
ieee80211_dump_frame(local->mdev->name,
"TX to low-level driver",
tx->u.tx.extra_frag[i]);
ret = local->ops->tx(local_to_hw(local),
tx->u.tx.extra_frag[i],
control);
if (ret)
return IEEE80211_TX_FRAG_AGAIN;
local->mdev->trans_start = jiffies;
ieee80211_led_tx(local, 1);
tx->u.tx.extra_frag[i] = NULL;
}
kfree(tx->u.tx.extra_frag);
tx->u.tx.extra_frag = NULL;
}
return IEEE80211_TX_OK;
}
static int ieee80211_tx(struct net_device *dev, struct sk_buff *skb,
struct ieee80211_tx_control *control, int mgmt)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct sta_info *sta;
ieee80211_tx_handler *handler;
struct ieee80211_txrx_data tx;
ieee80211_txrx_result res = TXRX_DROP, res_prepare;
int ret, i;
WARN_ON(__ieee80211_queue_pending(local, control->queue));
if (unlikely(skb->len < 10)) {
dev_kfree_skb(skb);
return 0;
}
res_prepare = __ieee80211_tx_prepare(&tx, skb, dev, control);
if (res_prepare == TXRX_DROP) {
dev_kfree_skb(skb);
return 0;
}
/*
* key references are protected using RCU and this requires that
* we are in a read-site RCU section during receive processing
*/
rcu_read_lock();
sta = tx.sta;
tx.u.tx.mgmt_interface = mgmt;
tx.u.tx.mode = local->hw.conf.mode;
if (res_prepare == TXRX_QUEUED) { /* if it was an injected packet */
res = TXRX_CONTINUE;
} else {
for (handler = local->tx_handlers; *handler != NULL;
handler++) {
res = (*handler)(&tx);
if (res != TXRX_CONTINUE)
break;
}
}
skb = tx.skb; /* handlers are allowed to change skb */
if (sta)
sta_info_put(sta);
if (unlikely(res == TXRX_DROP)) {
I802_DEBUG_INC(local->tx_handlers_drop);
goto drop;
}
if (unlikely(res == TXRX_QUEUED)) {
I802_DEBUG_INC(local->tx_handlers_queued);
rcu_read_unlock();
return 0;
}
if (tx.u.tx.extra_frag) {
for (i = 0; i < tx.u.tx.num_extra_frag; i++) {
int next_len, dur;
struct ieee80211_hdr *hdr =
(struct ieee80211_hdr *)
tx.u.tx.extra_frag[i]->data;
if (i + 1 < tx.u.tx.num_extra_frag) {
next_len = tx.u.tx.extra_frag[i + 1]->len;
} else {
next_len = 0;
tx.u.tx.rate = tx.u.tx.last_frag_rate;
tx.u.tx.last_frag_hwrate = tx.u.tx.rate->val;
}
dur = ieee80211_duration(&tx, 0, next_len);
hdr->duration_id = cpu_to_le16(dur);
}
}
retry:
ret = __ieee80211_tx(local, skb, &tx);
if (ret) {
struct ieee80211_tx_stored_packet *store =
&local->pending_packet[control->queue];
if (ret == IEEE80211_TX_FRAG_AGAIN)
skb = NULL;
set_bit(IEEE80211_LINK_STATE_PENDING,
&local->state[control->queue]);
smp_mb();
/* When the driver gets out of buffers during sending of
* fragments and calls ieee80211_stop_queue, there is
* a small window between IEEE80211_LINK_STATE_XOFF and
* IEEE80211_LINK_STATE_PENDING flags are set. If a buffer
* gets available in that window (i.e. driver calls
* ieee80211_wake_queue), we would end up with ieee80211_tx
* called with IEEE80211_LINK_STATE_PENDING. Prevent this by
* continuing transmitting here when that situation is
* possible to have happened. */
if (!__ieee80211_queue_stopped(local, control->queue)) {
clear_bit(IEEE80211_LINK_STATE_PENDING,
&local->state[control->queue]);
goto retry;
}
memcpy(&store->control, control,
sizeof(struct ieee80211_tx_control));
store->skb = skb;
store->extra_frag = tx.u.tx.extra_frag;
store->num_extra_frag = tx.u.tx.num_extra_frag;
store->last_frag_hwrate = tx.u.tx.last_frag_hwrate;
store->last_frag_rate = tx.u.tx.last_frag_rate;
store->last_frag_rate_ctrl_probe =
!!(tx.flags & IEEE80211_TXRXD_TXPROBE_LAST_FRAG);
}
rcu_read_unlock();
return 0;
drop:
if (skb)
dev_kfree_skb(skb);
for (i = 0; i < tx.u.tx.num_extra_frag; i++)
if (tx.u.tx.extra_frag[i])
dev_kfree_skb(tx.u.tx.extra_frag[i]);
kfree(tx.u.tx.extra_frag);
rcu_read_unlock();
return 0;
}
/* device xmit handlers */
int ieee80211_master_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct ieee80211_tx_control control;
struct ieee80211_tx_packet_data *pkt_data;
struct net_device *odev = NULL;
struct ieee80211_sub_if_data *osdata;
int headroom;
int ret;
/*
* copy control out of the skb so other people can use skb->cb
*/
pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
memset(&control, 0, sizeof(struct ieee80211_tx_control));
if (pkt_data->ifindex)
odev = dev_get_by_index(&init_net, pkt_data->ifindex);
if (unlikely(odev && !is_ieee80211_device(odev, dev))) {
dev_put(odev);
odev = NULL;
}
if (unlikely(!odev)) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Discarded packet with nonexistent "
"originating device\n", dev->name);
#endif
dev_kfree_skb(skb);
return 0;
}
osdata = IEEE80211_DEV_TO_SUB_IF(odev);
headroom = osdata->local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM;
if (skb_headroom(skb) < headroom) {
if (pskb_expand_head(skb, headroom, 0, GFP_ATOMIC)) {
dev_kfree_skb(skb);
dev_put(odev);
return 0;
}
}
control.ifindex = odev->ifindex;
control.type = osdata->type;
if (pkt_data->flags & IEEE80211_TXPD_REQ_TX_STATUS)
control.flags |= IEEE80211_TXCTL_REQ_TX_STATUS;
if (pkt_data->flags & IEEE80211_TXPD_DO_NOT_ENCRYPT)
control.flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT;
if (pkt_data->flags & IEEE80211_TXPD_REQUEUE)
control.flags |= IEEE80211_TXCTL_REQUEUE;
control.queue = pkt_data->queue;
ret = ieee80211_tx(odev, skb, &control,
control.type == IEEE80211_IF_TYPE_MGMT);
dev_put(odev);
return ret;
}
int ieee80211_monitor_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_tx_packet_data *pkt_data;
struct ieee80211_radiotap_header *prthdr =
(struct ieee80211_radiotap_header *)skb->data;
u16 len_rthdr;
/* check for not even having the fixed radiotap header part */
if (unlikely(skb->len < sizeof(struct ieee80211_radiotap_header)))
goto fail; /* too short to be possibly valid */
/* is it a header version we can trust to find length from? */
if (unlikely(prthdr->it_version))
goto fail; /* only version 0 is supported */
/* then there must be a radiotap header with a length we can use */
len_rthdr = ieee80211_get_radiotap_len(skb->data);
/* does the skb contain enough to deliver on the alleged length? */
if (unlikely(skb->len < len_rthdr))
goto fail; /* skb too short for claimed rt header extent */
skb->dev = local->mdev;
pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
memset(pkt_data, 0, sizeof(*pkt_data));
/* needed because we set skb device to master */
pkt_data->ifindex = dev->ifindex;
pkt_data->flags |= IEEE80211_TXPD_DO_NOT_ENCRYPT;
/*
* fix up the pointers accounting for the radiotap
* header still being in there. We are being given
* a precooked IEEE80211 header so no need for
* normal processing
*/
skb_set_mac_header(skb, len_rthdr);
/*
* these are just fixed to the end of the rt area since we
* don't have any better information and at this point, nobody cares
*/
skb_set_network_header(skb, len_rthdr);
skb_set_transport_header(skb, len_rthdr);
/* pass the radiotap header up to the next stage intact */
dev_queue_xmit(skb);
return NETDEV_TX_OK;
fail:
dev_kfree_skb(skb);
return NETDEV_TX_OK; /* meaning, we dealt with the skb */
}
/**
* ieee80211_subif_start_xmit - netif start_xmit function for Ethernet-type
* subinterfaces (wlan#, WDS, and VLAN interfaces)
* @skb: packet to be sent
* @dev: incoming interface
*
* Returns: 0 on success (and frees skb in this case) or 1 on failure (skb will
* not be freed, and caller is responsible for either retrying later or freeing
* skb).
*
* This function takes in an Ethernet header and encapsulates it with suitable
* IEEE 802.11 header based on which interface the packet is coming in. The
* encapsulated packet will then be passed to master interface, wlan#.11, for
* transmission (through low-level driver).
*/
int ieee80211_subif_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_tx_packet_data *pkt_data;
struct ieee80211_sub_if_data *sdata;
int ret = 1, head_need;
u16 ethertype, hdrlen, fc;
struct ieee80211_hdr hdr;
const u8 *encaps_data;
int encaps_len, skip_header_bytes;
int nh_pos, h_pos;
struct sta_info *sta;
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
if (unlikely(skb->len < ETH_HLEN)) {
printk(KERN_DEBUG "%s: short skb (len=%d)\n",
dev->name, skb->len);
ret = 0;
goto fail;
}
nh_pos = skb_network_header(skb) - skb->data;
h_pos = skb_transport_header(skb) - skb->data;
/* convert Ethernet header to proper 802.11 header (based on
* operation mode) */
ethertype = (skb->data[12] << 8) | skb->data[13];
/* TODO: handling for 802.1x authorized/unauthorized port */
fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
switch (sdata->type) {
case IEEE80211_IF_TYPE_AP:
case IEEE80211_IF_TYPE_VLAN:
fc |= IEEE80211_FCTL_FROMDS;
/* DA BSSID SA */
memcpy(hdr.addr1, skb->data, ETH_ALEN);
memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
hdrlen = 24;
break;
case IEEE80211_IF_TYPE_WDS:
fc |= IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS;
/* RA TA DA SA */
memcpy(hdr.addr1, sdata->u.wds.remote_addr, ETH_ALEN);
memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
memcpy(hdr.addr3, skb->data, ETH_ALEN);
memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
hdrlen = 30;
break;
case IEEE80211_IF_TYPE_STA:
fc |= IEEE80211_FCTL_TODS;
/* BSSID SA DA */
memcpy(hdr.addr1, sdata->u.sta.bssid, ETH_ALEN);
memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
memcpy(hdr.addr3, skb->data, ETH_ALEN);
hdrlen = 24;
break;
case IEEE80211_IF_TYPE_IBSS:
/* DA SA BSSID */
memcpy(hdr.addr1, skb->data, ETH_ALEN);
memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
memcpy(hdr.addr3, sdata->u.sta.bssid, ETH_ALEN);
hdrlen = 24;
break;
default:
ret = 0;
goto fail;
}
/* receiver is QoS enabled, use a QoS type frame */
sta = sta_info_get(local, hdr.addr1);
if (sta) {
if (sta->flags & WLAN_STA_WME) {
fc |= IEEE80211_STYPE_QOS_DATA;
hdrlen += 2;
}
sta_info_put(sta);
}
hdr.frame_control = cpu_to_le16(fc);
hdr.duration_id = 0;
hdr.seq_ctrl = 0;
skip_header_bytes = ETH_HLEN;
if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
encaps_data = bridge_tunnel_header;
encaps_len = sizeof(bridge_tunnel_header);
skip_header_bytes -= 2;
} else if (ethertype >= 0x600) {
encaps_data = rfc1042_header;
encaps_len = sizeof(rfc1042_header);
skip_header_bytes -= 2;
} else {
encaps_data = NULL;
encaps_len = 0;
}
skb_pull(skb, skip_header_bytes);
nh_pos -= skip_header_bytes;
h_pos -= skip_header_bytes;
/* TODO: implement support for fragments so that there is no need to
* reallocate and copy payload; it might be enough to support one
* extra fragment that would be copied in the beginning of the frame
* data.. anyway, it would be nice to include this into skb structure
* somehow
*
* There are few options for this:
* use skb->cb as an extra space for 802.11 header
* allocate new buffer if not enough headroom
* make sure that there is enough headroom in every skb by increasing
* build in headroom in __dev_alloc_skb() (linux/skbuff.h) and
* alloc_skb() (net/core/skbuff.c)
*/
head_need = hdrlen + encaps_len + local->tx_headroom;
head_need -= skb_headroom(skb);
/* We are going to modify skb data, so make a copy of it if happens to
* be cloned. This could happen, e.g., with Linux bridge code passing
* us broadcast frames. */
if (head_need > 0 || skb_cloned(skb)) {
#if 0
printk(KERN_DEBUG "%s: need to reallocate buffer for %d bytes "
"of headroom\n", dev->name, head_need);
#endif
if (skb_cloned(skb))
I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
else
I802_DEBUG_INC(local->tx_expand_skb_head);
/* Since we have to reallocate the buffer, make sure that there
* is enough room for possible WEP IV/ICV and TKIP (8 bytes
* before payload and 12 after). */
if (pskb_expand_head(skb, (head_need > 0 ? head_need + 8 : 8),
12, GFP_ATOMIC)) {
printk(KERN_DEBUG "%s: failed to reallocate TX buffer"
"\n", dev->name);
goto fail;
}
}
if (encaps_data) {
memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
nh_pos += encaps_len;
h_pos += encaps_len;
}
if (fc & IEEE80211_STYPE_QOS_DATA) {
__le16 *qos_control;
qos_control = (__le16*) skb_push(skb, 2);
memcpy(skb_push(skb, hdrlen - 2), &hdr, hdrlen - 2);
/*
* Maybe we could actually set some fields here, for now just
* initialise to zero to indicate no special operation.
*/
*qos_control = 0;
} else
memcpy(skb_push(skb, hdrlen), &hdr, hdrlen);
nh_pos += hdrlen;
h_pos += hdrlen;
pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
memset(pkt_data, 0, sizeof(struct ieee80211_tx_packet_data));
pkt_data->ifindex = dev->ifindex;
if (sdata->type == IEEE80211_IF_TYPE_MGMT)
pkt_data->flags |= IEEE80211_TXPD_MGMT_IFACE;
skb->dev = local->mdev;
sdata->stats.tx_packets++;
sdata->stats.tx_bytes += skb->len;
/* Update skb pointers to various headers since this modified frame
* is going to go through Linux networking code that may potentially
* need things like pointer to IP header. */
skb_set_mac_header(skb, 0);
skb_set_network_header(skb, nh_pos);
skb_set_transport_header(skb, h_pos);
dev->trans_start = jiffies;
dev_queue_xmit(skb);
return 0;
fail:
if (!ret)
dev_kfree_skb(skb);
return ret;
}
/*
* This is the transmit routine for the 802.11 type interfaces
* called by upper layers of the linux networking
* stack when it has a frame to transmit
*/
int ieee80211_mgmt_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ieee80211_sub_if_data *sdata;
struct ieee80211_tx_packet_data *pkt_data;
struct ieee80211_hdr *hdr;
u16 fc;
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
if (skb->len < 10) {
dev_kfree_skb(skb);
return 0;
}
if (skb_headroom(skb) < sdata->local->tx_headroom) {
if (pskb_expand_head(skb, sdata->local->tx_headroom,
0, GFP_ATOMIC)) {
dev_kfree_skb(skb);
return 0;
}
}
hdr = (struct ieee80211_hdr *) skb->data;
fc = le16_to_cpu(hdr->frame_control);
pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
memset(pkt_data, 0, sizeof(struct ieee80211_tx_packet_data));
pkt_data->ifindex = sdata->dev->ifindex;
if (sdata->type == IEEE80211_IF_TYPE_MGMT)
pkt_data->flags |= IEEE80211_TXPD_MGMT_IFACE;
skb->priority = 20; /* use hardcoded priority for mgmt TX queue */
skb->dev = sdata->local->mdev;
/*
* We're using the protocol field of the the frame control header
* to request TX callback for hostapd. BIT(1) is checked.
*/
if ((fc & BIT(1)) == BIT(1)) {
pkt_data->flags |= IEEE80211_TXPD_REQ_TX_STATUS;
fc &= ~BIT(1);
hdr->frame_control = cpu_to_le16(fc);
}
if (!(fc & IEEE80211_FCTL_PROTECTED))
pkt_data->flags |= IEEE80211_TXPD_DO_NOT_ENCRYPT;
sdata->stats.tx_packets++;
sdata->stats.tx_bytes += skb->len;
dev_queue_xmit(skb);
return 0;
}
/* helper functions for pending packets for when queues are stopped */
void ieee80211_clear_tx_pending(struct ieee80211_local *local)
{
int i, j;
struct ieee80211_tx_stored_packet *store;
for (i = 0; i < local->hw.queues; i++) {
if (!__ieee80211_queue_pending(local, i))
continue;
store = &local->pending_packet[i];
kfree_skb(store->skb);
for (j = 0; j < store->num_extra_frag; j++)
kfree_skb(store->extra_frag[j]);
kfree(store->extra_frag);
clear_bit(IEEE80211_LINK_STATE_PENDING, &local->state[i]);
}
}
void ieee80211_tx_pending(unsigned long data)
{
struct ieee80211_local *local = (struct ieee80211_local *)data;
struct net_device *dev = local->mdev;
struct ieee80211_tx_stored_packet *store;
struct ieee80211_txrx_data tx;
int i, ret, reschedule = 0;
netif_tx_lock_bh(dev);
for (i = 0; i < local->hw.queues; i++) {
if (__ieee80211_queue_stopped(local, i))
continue;
if (!__ieee80211_queue_pending(local, i)) {
reschedule = 1;
continue;
}
store = &local->pending_packet[i];
tx.u.tx.control = &store->control;
tx.u.tx.extra_frag = store->extra_frag;
tx.u.tx.num_extra_frag = store->num_extra_frag;
tx.u.tx.last_frag_hwrate = store->last_frag_hwrate;
tx.u.tx.last_frag_rate = store->last_frag_rate;
tx.flags = 0;
if (store->last_frag_rate_ctrl_probe)
tx.flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
ret = __ieee80211_tx(local, store->skb, &tx);
if (ret) {
if (ret == IEEE80211_TX_FRAG_AGAIN)
store->skb = NULL;
} else {
clear_bit(IEEE80211_LINK_STATE_PENDING,
&local->state[i]);
reschedule = 1;
}
}
netif_tx_unlock_bh(dev);
if (reschedule) {
if (!ieee80211_qdisc_installed(dev)) {
if (!__ieee80211_queue_stopped(local, 0))
netif_wake_queue(dev);
} else
netif_schedule(dev);
}
}
/* functions for drivers to get certain frames */
static void ieee80211_beacon_add_tim(struct ieee80211_local *local,
struct ieee80211_if_ap *bss,
struct sk_buff *skb)
{
u8 *pos, *tim;
int aid0 = 0;
int i, have_bits = 0, n1, n2;
/* Generate bitmap for TIM only if there are any STAs in power save
* mode. */
read_lock_bh(&local->sta_lock);
if (atomic_read(&bss->num_sta_ps) > 0)
/* in the hope that this is faster than
* checking byte-for-byte */
have_bits = !bitmap_empty((unsigned long*)bss->tim,
IEEE80211_MAX_AID+1);
if (bss->dtim_count == 0)
bss->dtim_count = bss->dtim_period - 1;
else
bss->dtim_count--;
tim = pos = (u8 *) skb_put(skb, 6);
*pos++ = WLAN_EID_TIM;
*pos++ = 4;
*pos++ = bss->dtim_count;
*pos++ = bss->dtim_period;
if (bss->dtim_count == 0 && !skb_queue_empty(&bss->ps_bc_buf))
aid0 = 1;
if (have_bits) {
/* Find largest even number N1 so that bits numbered 1 through
* (N1 x 8) - 1 in the bitmap are 0 and number N2 so that bits
* (N2 + 1) x 8 through 2007 are 0. */
n1 = 0;
for (i = 0; i < IEEE80211_MAX_TIM_LEN; i++) {
if (bss->tim[i]) {
n1 = i & 0xfe;
break;
}
}
n2 = n1;
for (i = IEEE80211_MAX_TIM_LEN - 1; i >= n1; i--) {
if (bss->tim[i]) {
n2 = i;
break;
}
}
/* Bitmap control */
*pos++ = n1 | aid0;
/* Part Virt Bitmap */
memcpy(pos, bss->tim + n1, n2 - n1 + 1);
tim[1] = n2 - n1 + 4;
skb_put(skb, n2 - n1);
} else {
*pos++ = aid0; /* Bitmap control */
*pos++ = 0; /* Part Virt Bitmap */
}
read_unlock_bh(&local->sta_lock);
}
struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw, int if_id,
struct ieee80211_tx_control *control)
{
struct ieee80211_local *local = hw_to_local(hw);
struct sk_buff *skb;
struct net_device *bdev;
struct ieee80211_sub_if_data *sdata = NULL;
struct ieee80211_if_ap *ap = NULL;
struct ieee80211_rate *rate;
struct rate_control_extra extra;
u8 *b_head, *b_tail;
int bh_len, bt_len;
bdev = dev_get_by_index(&init_net, if_id);
if (bdev) {
sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
ap = &sdata->u.ap;
dev_put(bdev);
}
if (!ap || sdata->type != IEEE80211_IF_TYPE_AP ||
!ap->beacon_head) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
if (net_ratelimit())
printk(KERN_DEBUG "no beacon data avail for idx=%d "
"(%s)\n", if_id, bdev ? bdev->name : "N/A");
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
return NULL;
}
/* Assume we are generating the normal beacon locally */
b_head = ap->beacon_head;
b_tail = ap->beacon_tail;
bh_len = ap->beacon_head_len;
bt_len = ap->beacon_tail_len;
skb = dev_alloc_skb(local->tx_headroom +
bh_len + bt_len + 256 /* maximum TIM len */);
if (!skb)
return NULL;
skb_reserve(skb, local->tx_headroom);
memcpy(skb_put(skb, bh_len), b_head, bh_len);
ieee80211_include_sequence(sdata, (struct ieee80211_hdr *)skb->data);
ieee80211_beacon_add_tim(local, ap, skb);
if (b_tail) {
memcpy(skb_put(skb, bt_len), b_tail, bt_len);
}
if (control) {
memset(&extra, 0, sizeof(extra));
extra.mode = local->oper_hw_mode;
rate = rate_control_get_rate(local, local->mdev, skb, &extra);
if (!rate) {
if (net_ratelimit()) {
printk(KERN_DEBUG "%s: ieee80211_beacon_get: no rate "
"found\n", local->mdev->name);
}
dev_kfree_skb(skb);
return NULL;
}
control->tx_rate =
((sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE) &&
(rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
rate->val2 : rate->val;
control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
control->power_level = local->hw.conf.power_level;
control->flags |= IEEE80211_TXCTL_NO_ACK;
control->retry_limit = 1;
control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
}
ap->num_beacons++;
return skb;
}
EXPORT_SYMBOL(ieee80211_beacon_get);
void ieee80211_rts_get(struct ieee80211_hw *hw, int if_id,
const void *frame, size_t frame_len,
const struct ieee80211_tx_control *frame_txctl,
struct ieee80211_rts *rts)
{
const struct ieee80211_hdr *hdr = frame;
u16 fctl;
fctl = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS;
rts->frame_control = cpu_to_le16(fctl);
rts->duration = ieee80211_rts_duration(hw, if_id, frame_len, frame_txctl);
memcpy(rts->ra, hdr->addr1, sizeof(rts->ra));
memcpy(rts->ta, hdr->addr2, sizeof(rts->ta));
}
EXPORT_SYMBOL(ieee80211_rts_get);
void ieee80211_ctstoself_get(struct ieee80211_hw *hw, int if_id,
const void *frame, size_t frame_len,
const struct ieee80211_tx_control *frame_txctl,
struct ieee80211_cts *cts)
{
const struct ieee80211_hdr *hdr = frame;
u16 fctl;
fctl = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS;
cts->frame_control = cpu_to_le16(fctl);
cts->duration = ieee80211_ctstoself_duration(hw, if_id, frame_len, frame_txctl);
memcpy(cts->ra, hdr->addr1, sizeof(cts->ra));
}
EXPORT_SYMBOL(ieee80211_ctstoself_get);
struct sk_buff *
ieee80211_get_buffered_bc(struct ieee80211_hw *hw, int if_id,
struct ieee80211_tx_control *control)
{
struct ieee80211_local *local = hw_to_local(hw);
struct sk_buff *skb;
struct sta_info *sta;
ieee80211_tx_handler *handler;
struct ieee80211_txrx_data tx;
ieee80211_txrx_result res = TXRX_DROP;
struct net_device *bdev;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_if_ap *bss = NULL;
bdev = dev_get_by_index(&init_net, if_id);
if (bdev) {
sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
bss = &sdata->u.ap;
dev_put(bdev);
}
if (!bss || sdata->type != IEEE80211_IF_TYPE_AP || !bss->beacon_head)
return NULL;
if (bss->dtim_count != 0)
return NULL; /* send buffered bc/mc only after DTIM beacon */
memset(control, 0, sizeof(*control));
while (1) {
skb = skb_dequeue(&bss->ps_bc_buf);
if (!skb)
return NULL;
local->total_ps_buffered--;
if (!skb_queue_empty(&bss->ps_bc_buf) && skb->len >= 2) {
struct ieee80211_hdr *hdr =
(struct ieee80211_hdr *) skb->data;
/* more buffered multicast/broadcast frames ==> set
* MoreData flag in IEEE 802.11 header to inform PS
* STAs */
hdr->frame_control |=
cpu_to_le16(IEEE80211_FCTL_MOREDATA);
}
if (ieee80211_tx_prepare(&tx, skb, local->mdev, control) == 0)
break;
dev_kfree_skb_any(skb);
}
sta = tx.sta;
tx.flags |= IEEE80211_TXRXD_TXPS_BUFFERED;
for (handler = local->tx_handlers; *handler != NULL; handler++) {
res = (*handler)(&tx);
if (res == TXRX_DROP || res == TXRX_QUEUED)
break;
}
dev_put(tx.dev);
skb = tx.skb; /* handlers are allowed to change skb */
if (res == TXRX_DROP) {
I802_DEBUG_INC(local->tx_handlers_drop);
dev_kfree_skb(skb);
skb = NULL;
} else if (res == TXRX_QUEUED) {
I802_DEBUG_INC(local->tx_handlers_queued);
skb = NULL;
}
if (sta)
sta_info_put(sta);
return skb;
}
EXPORT_SYMBOL(ieee80211_get_buffered_bc);
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