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linux/net/mac80211/tx.c

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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>
[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>
2007-09-14 08:10:24 -07:00
#include <linux/rcupdate.h>
[NET]: Make the device list and device lookups per namespace. This patch makes most of the generic device layer network namespace safe. This patch makes dev_base_head a network namespace variable, and then it picks up a few associated variables. The functions: dev_getbyhwaddr dev_getfirsthwbytype dev_get_by_flags dev_get_by_name __dev_get_by_name dev_get_by_index __dev_get_by_index dev_ioctl dev_ethtool dev_load wireless_process_ioctl were modified to take a network namespace argument, and deal with it. vlan_ioctl_set and brioctl_set were modified so their hooks will receive a network namespace argument. So basically anthing in the core of the network stack that was affected to by the change of dev_base was modified to handle multiple network namespaces. The rest of the network stack was simply modified to explicitly use &init_net the initial network namespace. This can be fixed when those components of the network stack are modified to handle multiple network namespaces. For now the ifindex generator is left global. Fundametally ifindex numbers are per namespace, or else we will have corner case problems with migration when we get that far. At the same time there are assumptions in the network stack that the ifindex of a network device won't change. Making the ifindex number global seems a good compromise until the network stack can cope with ifindex changes when you change namespaces, and the like. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-17 11:56:21 -07:00
#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 "led.h"
#include "mesh.h"
#include "wep.h"
#include "wpa.h"
#include "wme.h"
#include "rate.h"
#define IEEE80211_TX_OK 0
#define IEEE80211_TX_AGAIN 1
#define IEEE80211_TX_PENDING 2
/* misc utils */
static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr,
int next_frag_len)
{
int rate, mrate, erp, dur, i;
struct ieee80211_rate *txrate;
struct ieee80211_local *local = tx->local;
struct ieee80211_supported_band *sband;
struct ieee80211_hdr *hdr;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
/* assume HW handles this */
if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS)
return 0;
/* uh huh? */
if (WARN_ON_ONCE(info->control.rates[0].idx < 0))
return 0;
sband = local->hw.wiphy->bands[tx->channel->band];
txrate = &sband->bitrates[info->control.rates[0].idx];
erp = txrate->flags & IEEE80211_RATE_ERP_G;
/*
* 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
*/
hdr = (struct ieee80211_hdr *)tx->skb->data;
if (ieee80211_is_ctl(hdr->frame_control)) {
/* TODO: These control frames are not currently sent by
* mac80211, 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 cpu_to_le16(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;
/* use lowest available if everything fails */
mrate = sband->bitrates[0].bitrate;
for (i = 0; i < sband->n_bitrates; i++) {
struct ieee80211_rate *r = &sband->bitrates[i];
if (r->bitrate > txrate->bitrate)
break;
if (tx->sdata->vif.bss_conf.basic_rates & BIT(i))
rate = r->bitrate;
switch (sband->band) {
case IEEE80211_BAND_2GHZ: {
u32 flag;
if (tx->sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
flag = IEEE80211_RATE_MANDATORY_G;
else
flag = IEEE80211_RATE_MANDATORY_B;
if (r->flags & flag)
mrate = r->bitrate;
break;
}
case IEEE80211_BAND_5GHZ:
if (r->flags & IEEE80211_RATE_MANDATORY_A)
mrate = r->bitrate;
break;
case IEEE80211_NUM_BANDS:
WARN_ON(1);
break;
}
}
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->vif.bss_conf.use_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->bitrate, erp,
tx->sdata->vif.bss_conf.use_short_preamble);
}
return cpu_to_le16(dur);
}
static int inline is_ieee80211_device(struct ieee80211_local *local,
struct net_device *dev)
{
return local == wdev_priv(dev->ieee80211_ptr);
}
/* tx handlers */
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
u32 sta_flags;
if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED))
return TX_CONTINUE;
if (unlikely(tx->local->sw_scanning) &&
!ieee80211_is_probe_req(hdr->frame_control) &&
!ieee80211_is_nullfunc(hdr->frame_control))
/*
* When software scanning only nullfunc frames (to notify
* the sleep state to the AP) and probe requests (for the
* active scan) are allowed, all other frames should not be
* sent and we should not get here, but if we do
* nonetheless, drop them to avoid sending them
* off-channel. See the link below and
* ieee80211_start_scan() for more.
*
* http://article.gmane.org/gmane.linux.kernel.wireless.general/30089
*/
return TX_DROP;
if (tx->sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
return TX_CONTINUE;
if (tx->flags & IEEE80211_TX_PS_BUFFERED)
return TX_CONTINUE;
sta_flags = tx->sta ? get_sta_flags(tx->sta) : 0;
if (likely(tx->flags & IEEE80211_TX_UNICAST)) {
if (unlikely(!(sta_flags & WLAN_STA_ASSOC) &&
tx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
ieee80211_is_data(hdr->frame_control))) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: dropped data frame to not "
"associated station %pM\n",
tx->dev->name, hdr->addr1);
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
I802_DEBUG_INC(tx->local->tx_handlers_drop_not_assoc);
return TX_DROP;
}
} else {
if (unlikely(ieee80211_is_data(hdr->frame_control) &&
tx->local->num_sta == 0 &&
tx->sdata->vif.type != NL80211_IFTYPE_ADHOC)) {
/*
* No associated STAs - no need to send multicast
* frames.
*/
return TX_DROP;
}
return TX_CONTINUE;
}
return TX_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;
/*
* virtual interfaces are protected by RCU
*/
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
struct ieee80211_if_ap *ap;
if (sdata->vif.type != NL80211_IFTYPE_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);
}
list_for_each_entry_rcu(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);
}
rcu_read_unlock();
local->total_ps_buffered = total;
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "%s: PS buffers full - purged %d frames\n",
wiphy_name(local->hw.wiphy), purged);
#endif
}
static ieee80211_tx_result
ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
/*
* 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.
* This is done either by the hardware or us.
*/
/* powersaving STAs only in AP/VLAN mode */
if (!tx->sdata->bss)
return TX_CONTINUE;
/* no buffering for ordered frames */
if (ieee80211_has_order(hdr->frame_control))
return TX_CONTINUE;
/* no stations in PS mode */
if (!atomic_read(&tx->sdata->bss->num_sta_ps))
return TX_CONTINUE;
/* buffered in mac80211 */
if (tx->local->hw.flags & IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING) {
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) {
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
if (net_ratelimit()) {
printk(KERN_DEBUG "%s: BC TX buffer full - "
"dropping the oldest frame\n",
tx->dev->name);
}
#endif
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 TX_QUEUED;
}
/* buffered in hardware */
info->flags |= IEEE80211_TX_CTL_SEND_AFTER_DTIM;
return TX_CONTINUE;
}
static int ieee80211_use_mfp(__le16 fc, struct sta_info *sta,
struct sk_buff *skb)
{
if (!ieee80211_is_mgmt(fc))
return 0;
if (sta == NULL || !test_sta_flags(sta, WLAN_STA_MFP))
return 0;
if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *)
skb->data))
return 0;
return 1;
}
static ieee80211_tx_result
ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
{
struct sta_info *sta = tx->sta;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
u32 staflags;
if (unlikely(!sta || ieee80211_is_probe_resp(hdr->frame_control)))
return TX_CONTINUE;
staflags = get_sta_flags(sta);
if (unlikely((staflags & WLAN_STA_PS) &&
!(staflags & WLAN_STA_PSPOLL))) {
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "STA %pM aid %d: PS buffer (entries "
"before %d)\n",
sta->sta.addr, sta->sta.aid,
skb_queue_len(&sta->ps_tx_buf));
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
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);
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
if (net_ratelimit()) {
printk(KERN_DEBUG "%s: STA %pM TX "
"buffer full - dropping oldest frame\n",
tx->dev->name, sta->sta.addr);
}
#endif
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))
sta_info_set_tim_bit(sta);
info->control.jiffies = jiffies;
skb_queue_tail(&sta->ps_tx_buf, tx->skb);
return TX_QUEUED;
}
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
else if (unlikely(test_sta_flags(sta, WLAN_STA_PS))) {
printk(KERN_DEBUG "%s: STA %pM in PS mode, but pspoll "
"set -> send frame\n", tx->dev->name,
sta->sta.addr);
}
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
clear_sta_flags(sta, WLAN_STA_PSPOLL);
return TX_CONTINUE;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_ps_buf(struct ieee80211_tx_data *tx)
{
if (unlikely(tx->flags & IEEE80211_TX_PS_BUFFERED))
return TX_CONTINUE;
if (tx->flags & IEEE80211_TX_UNICAST)
return ieee80211_tx_h_unicast_ps_buf(tx);
else
return ieee80211_tx_h_multicast_ps_buf(tx);
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
{
[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>
2007-09-14 08:10:24 -07:00
struct ieee80211_key *key;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
[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>
2007-09-14 08:10:24 -07:00
if (unlikely(tx->skb->do_not_encrypt))
tx->key = NULL;
[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>
2007-09-14 08:10:24 -07:00
else if (tx->sta && (key = rcu_dereference(tx->sta->key)))
tx->key = key;
else if (ieee80211_is_mgmt(hdr->frame_control) &&
(key = rcu_dereference(tx->sdata->default_mgmt_key)))
tx->key = key;
[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>
2007-09-14 08:10:24 -07:00
else if ((key = rcu_dereference(tx->sdata->default_key)))
tx->key = key;
else if (tx->sdata->drop_unencrypted &&
(tx->skb->protocol != cpu_to_be16(ETH_P_PAE)) &&
!(info->flags & IEEE80211_TX_CTL_INJECTED) &&
(!ieee80211_is_robust_mgmt_frame(hdr) ||
(ieee80211_is_action(hdr->frame_control) &&
tx->sta && test_sta_flags(tx->sta, WLAN_STA_MFP)))) {
I802_DEBUG_INC(tx->local->tx_handlers_drop_unencrypted);
return TX_DROP;
} else
tx->key = NULL;
if (tx->key) {
tx->key->tx_rx_count++;
/* TODO: add threshold stuff again */
switch (tx->key->conf.alg) {
case ALG_WEP:
if (ieee80211_is_auth(hdr->frame_control))
break;
case ALG_TKIP:
if (!ieee80211_is_data_present(hdr->frame_control))
tx->key = NULL;
break;
case ALG_CCMP:
if (!ieee80211_is_data_present(hdr->frame_control) &&
!ieee80211_use_mfp(hdr->frame_control, tx->sta,
tx->skb))
tx->key = NULL;
break;
case ALG_AES_CMAC:
if (!ieee80211_is_mgmt(hdr->frame_control))
tx->key = NULL;
break;
}
}
if (!tx->key || !(tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
tx->skb->do_not_encrypt = 1;
return TX_CONTINUE;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_rate_ctrl(struct ieee80211_tx_data *tx)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
struct ieee80211_hdr *hdr = (void *)tx->skb->data;
struct ieee80211_supported_band *sband;
struct ieee80211_rate *rate;
int i, len;
bool inval = false, rts = false, short_preamble = false;
struct ieee80211_tx_rate_control txrc;
memset(&txrc, 0, sizeof(txrc));
sband = tx->local->hw.wiphy->bands[tx->channel->band];
len = min_t(int, tx->skb->len + FCS_LEN,
tx->local->fragmentation_threshold);
/* set up the tx rate control struct we give the RC algo */
txrc.hw = local_to_hw(tx->local);
txrc.sband = sband;
txrc.bss_conf = &tx->sdata->vif.bss_conf;
txrc.skb = tx->skb;
txrc.reported_rate.idx = -1;
txrc.max_rate_idx = tx->sdata->max_ratectrl_rateidx;
/* set up RTS protection if desired */
if (tx->local->rts_threshold < IEEE80211_MAX_RTS_THRESHOLD &&
len > tx->local->rts_threshold) {
txrc.rts = rts = true;
}
/*
* Use short preamble if the BSS can handle it, but not for
* management frames unless we know the receiver can handle
* that -- the management frame might be to a station that
* just wants a probe response.
*/
if (tx->sdata->vif.bss_conf.use_short_preamble &&
(ieee80211_is_data(hdr->frame_control) ||
(tx->sta && test_sta_flags(tx->sta, WLAN_STA_SHORT_PREAMBLE))))
txrc.short_preamble = short_preamble = true;
rate_control_get_rate(tx->sdata, tx->sta, &txrc);
if (unlikely(info->control.rates[0].idx < 0))
return TX_DROP;
if (txrc.reported_rate.idx < 0)
txrc.reported_rate = info->control.rates[0];
if (tx->sta)
tx->sta->last_tx_rate = txrc.reported_rate;
if (unlikely(!info->control.rates[0].count))
info->control.rates[0].count = 1;
if (is_multicast_ether_addr(hdr->addr1)) {
/*
* XXX: verify the rate is in the basic rateset
*/
return TX_CONTINUE;
}
/*
* set up the RTS/CTS rate as the fastest basic rate
* that is not faster than the data rate
*
* XXX: Should this check all retry rates?
*/
if (!(info->control.rates[0].flags & IEEE80211_TX_RC_MCS)) {
s8 baserate = 0;
rate = &sband->bitrates[info->control.rates[0].idx];
for (i = 0; i < sband->n_bitrates; i++) {
/* must be a basic rate */
if (!(tx->sdata->vif.bss_conf.basic_rates & BIT(i)))
continue;
/* must not be faster than the data rate */
if (sband->bitrates[i].bitrate > rate->bitrate)
continue;
/* maximum */
if (sband->bitrates[baserate].bitrate <
sband->bitrates[i].bitrate)
baserate = i;
}
info->control.rts_cts_rate_idx = baserate;
}
for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
/*
* make sure there's no valid rate following
* an invalid one, just in case drivers don't
* take the API seriously to stop at -1.
*/
if (inval) {
info->control.rates[i].idx = -1;
continue;
}
if (info->control.rates[i].idx < 0) {
inval = true;
continue;
}
/*
* For now assume MCS is already set up correctly, this
* needs to be fixed.
*/
if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS) {
WARN_ON(info->control.rates[i].idx > 76);
continue;
}
/* set up RTS protection if desired */
if (rts)
info->control.rates[i].flags |=
IEEE80211_TX_RC_USE_RTS_CTS;
/* RC is busted */
if (WARN_ON_ONCE(info->control.rates[i].idx >=
sband->n_bitrates)) {
info->control.rates[i].idx = -1;
continue;
}
rate = &sband->bitrates[info->control.rates[i].idx];
/* set up short preamble */
if (short_preamble &&
rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
info->control.rates[i].flags |=
IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
/* set up G protection */
if (!rts && tx->sdata->vif.bss_conf.use_cts_prot &&
rate->flags & IEEE80211_RATE_ERP_G)
info->control.rates[i].flags |=
IEEE80211_TX_RC_USE_CTS_PROTECT;
}
return TX_CONTINUE;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_misc(struct ieee80211_tx_data *tx)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
if (tx->sta)
info->control.sta = &tx->sta->sta;
return TX_CONTINUE;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
u16 *seq;
u8 *qc;
int tid;
/*
* Packet injection may want to control the sequence
* number, if we have no matching interface then we
* neither assign one ourselves nor ask the driver to.
*/
if (unlikely(!info->control.vif))
return TX_CONTINUE;
if (unlikely(ieee80211_is_ctl(hdr->frame_control)))
return TX_CONTINUE;
if (ieee80211_hdrlen(hdr->frame_control) < 24)
return TX_CONTINUE;
/*
* Anything but QoS data that has a sequence number field
* (is long enough) gets a sequence number from the global
* counter.
*/
if (!ieee80211_is_data_qos(hdr->frame_control)) {
/* driver should assign sequence number */
info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
/* for pure STA mode without beacons, we can do it */
hdr->seq_ctrl = cpu_to_le16(tx->sdata->sequence_number);
tx->sdata->sequence_number += 0x10;
tx->sdata->sequence_number &= IEEE80211_SCTL_SEQ;
return TX_CONTINUE;
}
/*
* This should be true for injected/management frames only, for
* management frames we have set the IEEE80211_TX_CTL_ASSIGN_SEQ
* above since they are not QoS-data frames.
*/
if (!tx->sta)
return TX_CONTINUE;
/* include per-STA, per-TID sequence counter */
qc = ieee80211_get_qos_ctl(hdr);
tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
seq = &tx->sta->tid_seq[tid];
hdr->seq_ctrl = cpu_to_le16(*seq);
/* Increase the sequence number. */
*seq = (*seq + 0x10) & IEEE80211_SCTL_SEQ;
return TX_CONTINUE;
}
static int ieee80211_fragment(struct ieee80211_local *local,
struct sk_buff *skb, int hdrlen,
int frag_threshold)
{
struct sk_buff *tail = skb, *tmp;
int per_fragm = frag_threshold - hdrlen - FCS_LEN;
int pos = hdrlen + per_fragm;
int rem = skb->len - hdrlen - per_fragm;
if (WARN_ON(rem < 0))
return -EINVAL;
while (rem) {
int fraglen = per_fragm;
if (fraglen > rem)
fraglen = rem;
rem -= fraglen;
tmp = dev_alloc_skb(local->tx_headroom +
frag_threshold +
IEEE80211_ENCRYPT_HEADROOM +
IEEE80211_ENCRYPT_TAILROOM);
if (!tmp)
return -ENOMEM;
tail->next = tmp;
tail = tmp;
skb_reserve(tmp, local->tx_headroom +
IEEE80211_ENCRYPT_HEADROOM);
/* copy control information */
memcpy(tmp->cb, skb->cb, sizeof(tmp->cb));
skb_copy_queue_mapping(tmp, skb);
tmp->priority = skb->priority;
tmp->do_not_encrypt = skb->do_not_encrypt;
tmp->dev = skb->dev;
tmp->iif = skb->iif;
/* copy header and data */
memcpy(skb_put(tmp, hdrlen), skb->data, hdrlen);
memcpy(skb_put(tmp, fraglen), skb->data + pos, fraglen);
pos += fraglen;
}
skb->len = hdrlen + per_fragm;
return 0;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
{
struct sk_buff *skb = tx->skb;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr = (void *)skb->data;
int frag_threshold = tx->local->fragmentation_threshold;
int hdrlen;
int fragnum;
if (!(tx->flags & IEEE80211_TX_FRAGMENTED))
return TX_CONTINUE;
/*
* Warn when submitting a fragmented A-MPDU frame and drop it.
* This scenario is handled in __ieee80211_tx_prepare but extra
* caution taken here as fragmented ampdu may cause Tx stop.
*/
if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
return TX_DROP;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
/* internal error, why is TX_FRAGMENTED set? */
if (WARN_ON(skb->len <= frag_threshold))
return TX_DROP;
/*
* Now fragment the frame. This will allocate all the fragments and
* chain them (using skb as the first fragment) to skb->next.
* During transmission, we will remove the successfully transmitted
* fragments from this list. When the low-level driver rejects one
* of the fragments then we will simply pretend to accept the skb
* but store it away as pending.
*/
if (ieee80211_fragment(tx->local, skb, hdrlen, frag_threshold))
return TX_DROP;
/* update duration/seq/flags of fragments */
fragnum = 0;
do {
int next_len;
const __le16 morefrags = cpu_to_le16(IEEE80211_FCTL_MOREFRAGS);
hdr = (void *)skb->data;
info = IEEE80211_SKB_CB(skb);
if (skb->next) {
hdr->frame_control |= morefrags;
next_len = skb->next->len;
/*
* No multi-rate retries for fragmented frames, that
* would completely throw off the NAV at other STAs.
*/
info->control.rates[1].idx = -1;
info->control.rates[2].idx = -1;
info->control.rates[3].idx = -1;
info->control.rates[4].idx = -1;
BUILD_BUG_ON(IEEE80211_TX_MAX_RATES != 5);
info->flags &= ~IEEE80211_TX_CTL_RATE_CTRL_PROBE;
} else {
hdr->frame_control &= ~morefrags;
next_len = 0;
}
hdr->duration_id = ieee80211_duration(tx, 0, next_len);
hdr->seq_ctrl |= cpu_to_le16(fragnum & IEEE80211_SCTL_FRAG);
fragnum++;
} while ((skb = skb->next));
return TX_CONTINUE;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_encrypt(struct ieee80211_tx_data *tx)
{
if (!tx->key)
return TX_CONTINUE;
switch (tx->key->conf.alg) {
case ALG_WEP:
return ieee80211_crypto_wep_encrypt(tx);
case ALG_TKIP:
return ieee80211_crypto_tkip_encrypt(tx);
case ALG_CCMP:
return ieee80211_crypto_ccmp_encrypt(tx);
case ALG_AES_CMAC:
return ieee80211_crypto_aes_cmac_encrypt(tx);
}
/* not reached */
WARN_ON(1);
return TX_DROP;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_calculate_duration(struct ieee80211_tx_data *tx)
{
struct sk_buff *skb = tx->skb;
struct ieee80211_hdr *hdr;
int next_len;
bool group_addr;
do {
hdr = (void *) skb->data;
next_len = skb->next ? skb->next->len : 0;
group_addr = is_multicast_ether_addr(hdr->addr1);
hdr->duration_id =
ieee80211_duration(tx, group_addr, next_len);
} while ((skb = skb->next));
return TX_CONTINUE;
}
static ieee80211_tx_result debug_noinline
ieee80211_tx_h_stats(struct ieee80211_tx_data *tx)
{
struct sk_buff *skb = tx->skb;
if (!tx->sta)
return TX_CONTINUE;
tx->sta->tx_packets++;
do {
tx->sta->tx_fragments++;
tx->sta->tx_bytes += skb->len;
} while ((skb = skb->next));
return TX_CONTINUE;
}
/* actual transmit path */
/*
* deal with packet injection down monitor interface
* with Radiotap Header -- only called for monitor mode interface
*/
static ieee80211_tx_result
__ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
struct sk_buff *skb)
{
/*
* 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_supported_band *sband;
int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
sband = tx->local->hw.wiphy->bands[tx->channel->band];
skb->do_not_encrypt = 1;
tx->flags &= ~IEEE80211_TX_FRAGMENTED;
/*
* for every radiotap entry that is present
* (ieee80211_radiotap_iterator_next returns -ENOENT when no more
* entries present, or -EINVAL on error)
*/
while (!ret) {
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_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 TX_DROP;
skb_trim(skb, skb->len - FCS_LEN);
}
if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
tx->skb->do_not_encrypt = 0;
if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
tx->flags |= IEEE80211_TX_FRAGMENTED;
break;
/*
* Please update the file
* Documentation/networking/mac80211-injection.txt
* when parsing new fields here.
*/
default:
break;
}
}
if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
return TX_DROP;
/*
* remove the radiotap header
* iterator->max_length was sanity-checked against
* skb->len by iterator init
*/
skb_pull(skb, iterator.max_length);
return TX_CONTINUE;
}
/*
* initialises @tx
*/
static ieee80211_tx_result
__ieee80211_tx_prepare(struct ieee80211_tx_data *tx,
struct sk_buff *skb,
struct net_device *dev)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_hdr *hdr;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
int hdrlen, tid;
u8 *qc, *state;
bool queued = false;
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->channel = local->hw.conf.channel;
/*
* Set this flag (used below to indicate "automatic fragmentation"),
* it will be cleared/left by radiotap as desired.
*/
tx->flags |= IEEE80211_TX_FRAGMENTED;
/* process and remove the injection radiotap header */
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED)) {
if (__ieee80211_parse_tx_radiotap(tx, skb) == TX_DROP)
return TX_DROP;
/*
* __ieee80211_parse_tx_radiotap has now removed
* the radiotap header that was present and pre-filled
* 'tx' with tx control information.
*/
}
/*
* If this flag is set to true anywhere, and we get here,
* we are doing the needed processing, so remove the flag
* now.
*/
info->flags &= ~IEEE80211_TX_INTFL_NEED_TXPROCESSING;
hdr = (struct ieee80211_hdr *) skb->data;
tx->sta = sta_info_get(local, hdr->addr1);
if (tx->sta && ieee80211_is_data_qos(hdr->frame_control) &&
(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION)) {
mac80211: fix aggregation for hardware with ampdu queues Hardware with AMPDU queues currently has broken aggregation. This patch fixes it by making all A-MPDUs go over the regular AC queues, but keeping track of the hardware queues in mac80211. As a first rough version, it actually stops the AC queue for extended periods of time, which can be removed by adding buffering internal to mac80211, but is currently not a huge problem because people rarely use multiple TIDs that are in the same AC (and iwlwifi currently doesn't operate as AP). This is a short-term fix, my current medium-term plan, which I hope to execute soon as well, but am not sure can finish before .30, looks like this: 1) rework the internal queuing layer in mac80211 that we use for fragments if the driver stopped queue in the middle of a fragmented frame to be able to queue more frames at once (rather than just a single frame with its fragments) 2) instead of stopping the entire AC queue, queue up the frames in a per-station/per-TID queue during aggregation session initiation, when the session has come up take all those frames and put them onto the queue from 1) 3) push the ampdu queue layer abstraction this patch introduces in mac80211 into the driver, and remove the virtual queue stuff from mac80211 again This plan will probably also affect ath9k in that mac80211 queues the frames instead of passing them down, even when there are no ampdu queues. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-02-11 16:51:53 -07:00
unsigned long flags;
struct tid_ampdu_tx *tid_tx;
qc = ieee80211_get_qos_ctl(hdr);
tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
mac80211: fix aggregation for hardware with ampdu queues Hardware with AMPDU queues currently has broken aggregation. This patch fixes it by making all A-MPDUs go over the regular AC queues, but keeping track of the hardware queues in mac80211. As a first rough version, it actually stops the AC queue for extended periods of time, which can be removed by adding buffering internal to mac80211, but is currently not a huge problem because people rarely use multiple TIDs that are in the same AC (and iwlwifi currently doesn't operate as AP). This is a short-term fix, my current medium-term plan, which I hope to execute soon as well, but am not sure can finish before .30, looks like this: 1) rework the internal queuing layer in mac80211 that we use for fragments if the driver stopped queue in the middle of a fragmented frame to be able to queue more frames at once (rather than just a single frame with its fragments) 2) instead of stopping the entire AC queue, queue up the frames in a per-station/per-TID queue during aggregation session initiation, when the session has come up take all those frames and put them onto the queue from 1) 3) push the ampdu queue layer abstraction this patch introduces in mac80211 into the driver, and remove the virtual queue stuff from mac80211 again This plan will probably also affect ath9k in that mac80211 queues the frames instead of passing them down, even when there are no ampdu queues. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-02-11 16:51:53 -07:00
spin_lock_irqsave(&tx->sta->lock, flags);
/*
* XXX: This spinlock could be fairly expensive, but see the
* comment in agg-tx.c:ieee80211_agg_tx_operational().
* One way to solve this would be to do something RCU-like
* for managing the tid_tx struct and using atomic bitops
* for the actual state -- by introducing an actual
* 'operational' bit that would be possible. It would
* require changing ieee80211_agg_tx_operational() to
* set that bit, and changing the way tid_tx is managed
* everywhere, including races between that bit and
* tid_tx going away (tid_tx being added can be easily
* committed to memory before the 'operational' bit).
*/
tid_tx = tx->sta->ampdu_mlme.tid_tx[tid];
state = &tx->sta->ampdu_mlme.tid_state_tx[tid];
if (*state == HT_AGG_STATE_OPERATIONAL) {
info->flags |= IEEE80211_TX_CTL_AMPDU;
} else if (*state != HT_AGG_STATE_IDLE) {
/* in progress */
queued = true;
info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
__skb_queue_tail(&tid_tx->pending, skb);
}
mac80211: fix aggregation for hardware with ampdu queues Hardware with AMPDU queues currently has broken aggregation. This patch fixes it by making all A-MPDUs go over the regular AC queues, but keeping track of the hardware queues in mac80211. As a first rough version, it actually stops the AC queue for extended periods of time, which can be removed by adding buffering internal to mac80211, but is currently not a huge problem because people rarely use multiple TIDs that are in the same AC (and iwlwifi currently doesn't operate as AP). This is a short-term fix, my current medium-term plan, which I hope to execute soon as well, but am not sure can finish before .30, looks like this: 1) rework the internal queuing layer in mac80211 that we use for fragments if the driver stopped queue in the middle of a fragmented frame to be able to queue more frames at once (rather than just a single frame with its fragments) 2) instead of stopping the entire AC queue, queue up the frames in a per-station/per-TID queue during aggregation session initiation, when the session has come up take all those frames and put them onto the queue from 1) 3) push the ampdu queue layer abstraction this patch introduces in mac80211 into the driver, and remove the virtual queue stuff from mac80211 again This plan will probably also affect ath9k in that mac80211 queues the frames instead of passing them down, even when there are no ampdu queues. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-02-11 16:51:53 -07:00
spin_unlock_irqrestore(&tx->sta->lock, flags);
if (unlikely(queued))
return TX_QUEUED;
}
if (is_multicast_ether_addr(hdr->addr1)) {
tx->flags &= ~IEEE80211_TX_UNICAST;
info->flags |= IEEE80211_TX_CTL_NO_ACK;
} else {
tx->flags |= IEEE80211_TX_UNICAST;
info->flags &= ~IEEE80211_TX_CTL_NO_ACK;
}
if (tx->flags & IEEE80211_TX_FRAGMENTED) {
if ((tx->flags & IEEE80211_TX_UNICAST) &&
skb->len + FCS_LEN > local->fragmentation_threshold &&
!(info->flags & IEEE80211_TX_CTL_AMPDU))
tx->flags |= IEEE80211_TX_FRAGMENTED;
else
tx->flags &= ~IEEE80211_TX_FRAGMENTED;
}
if (!tx->sta)
info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
else if (test_and_clear_sta_flags(tx->sta, WLAN_STA_CLEAR_PS_FILT))
info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (skb->len > hdrlen + sizeof(rfc1042_header) + 2) {
u8 *pos = &skb->data[hdrlen + sizeof(rfc1042_header)];
tx->ethertype = (pos[0] << 8) | pos[1];
}
info->flags |= IEEE80211_TX_CTL_FIRST_FRAGMENT;
return TX_CONTINUE;
}
/*
* NB: @tx is uninitialised when passed in here
*/
static int ieee80211_tx_prepare(struct ieee80211_local *local,
struct ieee80211_tx_data *tx,
struct sk_buff *skb)
{
struct net_device *dev;
dev = dev_get_by_index(&init_net, skb->iif);
if (unlikely(dev && !is_ieee80211_device(local, dev))) {
dev_put(dev);
dev = NULL;
}
if (unlikely(!dev))
return -ENODEV;
/*
* initialises tx with control
*
* return value is safe to ignore here because this function
* can only be invoked for multicast frames
*
* XXX: clean up
*/
__ieee80211_tx_prepare(tx, skb, dev);
dev_put(dev);
return 0;
}
static int __ieee80211_tx(struct ieee80211_local *local,
struct sk_buff **skbp,
struct sta_info *sta)
{
struct sk_buff *skb = *skbp, *next;
struct ieee80211_tx_info *info;
int ret, len;
bool fragm = false;
local->mdev->trans_start = jiffies;
while (skb) {
mac80211: fix aggregation for hardware with ampdu queues Hardware with AMPDU queues currently has broken aggregation. This patch fixes it by making all A-MPDUs go over the regular AC queues, but keeping track of the hardware queues in mac80211. As a first rough version, it actually stops the AC queue for extended periods of time, which can be removed by adding buffering internal to mac80211, but is currently not a huge problem because people rarely use multiple TIDs that are in the same AC (and iwlwifi currently doesn't operate as AP). This is a short-term fix, my current medium-term plan, which I hope to execute soon as well, but am not sure can finish before .30, looks like this: 1) rework the internal queuing layer in mac80211 that we use for fragments if the driver stopped queue in the middle of a fragmented frame to be able to queue more frames at once (rather than just a single frame with its fragments) 2) instead of stopping the entire AC queue, queue up the frames in a per-station/per-TID queue during aggregation session initiation, when the session has come up take all those frames and put them onto the queue from 1) 3) push the ampdu queue layer abstraction this patch introduces in mac80211 into the driver, and remove the virtual queue stuff from mac80211 again This plan will probably also affect ath9k in that mac80211 queues the frames instead of passing them down, even when there are no ampdu queues. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-02-11 16:51:53 -07:00
if (ieee80211_queue_stopped(&local->hw,
skb_get_queue_mapping(skb)))
return IEEE80211_TX_PENDING;
info = IEEE80211_SKB_CB(skb);
if (fragm)
info->flags &= ~(IEEE80211_TX_CTL_CLEAR_PS_FILT |
IEEE80211_TX_CTL_FIRST_FRAGMENT);
next = skb->next;
len = skb->len;
ret = local->ops->tx(local_to_hw(local), skb);
if (WARN_ON(ret != NETDEV_TX_OK && skb->len != len)) {
dev_kfree_skb(skb);
ret = NETDEV_TX_OK;
}
if (ret != NETDEV_TX_OK)
return IEEE80211_TX_AGAIN;
*skbp = skb = next;
ieee80211_led_tx(local, 1);
fragm = true;
}
return IEEE80211_TX_OK;
}
/*
* Invoke TX handlers, return 0 on success and non-zero if the
* frame was dropped or queued.
*/
static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
{
struct sk_buff *skb = tx->skb;
ieee80211_tx_result res = TX_DROP;
#define CALL_TXH(txh) \
res = txh(tx); \
if (res != TX_CONTINUE) \
goto txh_done;
CALL_TXH(ieee80211_tx_h_check_assoc)
CALL_TXH(ieee80211_tx_h_ps_buf)
CALL_TXH(ieee80211_tx_h_select_key)
CALL_TXH(ieee80211_tx_h_michael_mic_add)
CALL_TXH(ieee80211_tx_h_rate_ctrl)
CALL_TXH(ieee80211_tx_h_misc)
CALL_TXH(ieee80211_tx_h_sequence)
CALL_TXH(ieee80211_tx_h_fragment)
/* handlers after fragment must be aware of tx info fragmentation! */
CALL_TXH(ieee80211_tx_h_encrypt)
CALL_TXH(ieee80211_tx_h_calculate_duration)
CALL_TXH(ieee80211_tx_h_stats)
#undef CALL_TXH
txh_done:
if (unlikely(res == TX_DROP)) {
I802_DEBUG_INC(tx->local->tx_handlers_drop);
while (skb) {
struct sk_buff *next;
next = skb->next;
dev_kfree_skb(skb);
skb = next;
}
return -1;
} else if (unlikely(res == TX_QUEUED)) {
I802_DEBUG_INC(tx->local->tx_handlers_queued);
return -1;
}
return 0;
}
static void ieee80211_tx(struct net_device *dev, struct sk_buff *skb,
bool txpending)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct sta_info *sta;
struct ieee80211_tx_data tx;
ieee80211_tx_result res_prepare;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct sk_buff *next;
unsigned long flags;
int ret, retries;
u16 queue;
queue = skb_get_queue_mapping(skb);
WARN_ON(!txpending && !skb_queue_empty(&local->pending[queue]));
if (unlikely(skb->len < 10)) {
dev_kfree_skb(skb);
return;
}
rcu_read_lock();
/* initialises tx */
res_prepare = __ieee80211_tx_prepare(&tx, skb, dev);
if (unlikely(res_prepare == TX_DROP)) {
dev_kfree_skb(skb);
rcu_read_unlock();
return;
} else if (unlikely(res_prepare == TX_QUEUED)) {
rcu_read_unlock();
return;
}
sta = tx.sta;
tx.channel = local->hw.conf.channel;
info->band = tx.channel->band;
if (invoke_tx_handlers(&tx))
goto out;
retries = 0;
retry:
ret = __ieee80211_tx(local, &tx.skb, tx.sta);
switch (ret) {
case IEEE80211_TX_OK:
break;
case IEEE80211_TX_AGAIN:
/*
* Since there are no fragmented frames on A-MPDU
* queues, there's no reason for a driver to reject
* a frame there, warn and drop it.
*/
if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
goto drop;
/* fall through */
case IEEE80211_TX_PENDING:
skb = tx.skb;
spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
if (__netif_subqueue_stopped(local->mdev, queue)) {
do {
next = skb->next;
skb->next = NULL;
if (unlikely(txpending))
skb_queue_head(&local->pending[queue],
skb);
else
skb_queue_tail(&local->pending[queue],
skb);
} while ((skb = next));
/*
* Make sure nobody will enable the queue on us
* (without going through the tasklet) nor disable the
* netdev queue underneath the pending handling code.
*/
__set_bit(IEEE80211_QUEUE_STOP_REASON_PENDING,
&local->queue_stop_reasons[queue]);
spin_unlock_irqrestore(&local->queue_stop_reason_lock,
flags);
} else {
spin_unlock_irqrestore(&local->queue_stop_reason_lock,
flags);
retries++;
if (WARN(retries > 10, "tx refused but queue active"))
goto drop;
goto retry;
}
}
out:
[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>
2007-09-14 08:10:24 -07:00
rcu_read_unlock();
return;
drop:
[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>
2007-09-14 08:10:24 -07:00
rcu_read_unlock();
skb = tx.skb;
while (skb) {
next = skb->next;
dev_kfree_skb(skb);
skb = next;
}
}
/* device xmit handlers */
static int ieee80211_skb_resize(struct ieee80211_local *local,
struct sk_buff *skb,
int head_need, bool may_encrypt)
{
int tail_need = 0;
/*
* This could be optimised, devices that do full hardware
* crypto (including TKIP MMIC) need no tailroom... But we
* have no drivers for such devices currently.
*/
if (may_encrypt) {
tail_need = IEEE80211_ENCRYPT_TAILROOM;
tail_need -= skb_tailroom(skb);
tail_need = max_t(int, tail_need, 0);
}
if (head_need || tail_need) {
/* Sorry. Can't account for this any more */
skb_orphan(skb);
}
if (skb_header_cloned(skb))
I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
else
I802_DEBUG_INC(local->tx_expand_skb_head);
if (pskb_expand_head(skb, head_need, tail_need, GFP_ATOMIC)) {
printk(KERN_DEBUG "%s: failed to reallocate TX buffer\n",
wiphy_name(local->hw.wiphy));
return -ENOMEM;
}
/* update truesize too */
skb->truesize += head_need + tail_need;
return 0;
}
int ieee80211_master_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ieee80211_master_priv *mpriv = netdev_priv(dev);
struct ieee80211_local *local = mpriv->local;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct net_device *odev = NULL;
struct ieee80211_sub_if_data *osdata;
int headroom;
bool may_encrypt;
enum {
NOT_MONITOR,
FOUND_SDATA,
UNKNOWN_ADDRESS,
} monitor_iface = NOT_MONITOR;
if (skb->iif)
odev = dev_get_by_index(&init_net, skb->iif);
if (unlikely(odev && !is_ieee80211_device(local, odev))) {
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 NETDEV_TX_OK;
}
if ((local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK) &&
local->hw.conf.dynamic_ps_timeout > 0) {
if (local->hw.conf.flags & IEEE80211_CONF_PS) {
ieee80211_stop_queues_by_reason(&local->hw,
IEEE80211_QUEUE_STOP_REASON_PS);
queue_work(local->hw.workqueue,
&local->dynamic_ps_disable_work);
}
mod_timer(&local->dynamic_ps_timer, jiffies +
msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
}
memset(info, 0, sizeof(*info));
info->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
osdata = IEEE80211_DEV_TO_SUB_IF(odev);
if (ieee80211_vif_is_mesh(&osdata->vif) &&
ieee80211_is_data(hdr->frame_control)) {
if (is_multicast_ether_addr(hdr->addr3))
memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
else
if (mesh_nexthop_lookup(skb, osdata)) {
dev_put(odev);
return NETDEV_TX_OK;
}
if (memcmp(odev->dev_addr, hdr->addr4, ETH_ALEN) != 0)
IEEE80211_IFSTA_MESH_CTR_INC(&osdata->u.mesh,
fwded_frames);
} else if (unlikely(osdata->vif.type == NL80211_IFTYPE_MONITOR)) {
struct ieee80211_sub_if_data *sdata;
int hdrlen;
u16 len_rthdr;
info->flags |= IEEE80211_TX_CTL_INJECTED;
monitor_iface = UNKNOWN_ADDRESS;
len_rthdr = ieee80211_get_radiotap_len(skb->data);
hdr = (struct ieee80211_hdr *)skb->data + len_rthdr;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
/* check the header is complete in the frame */
if (likely(skb->len >= len_rthdr + hdrlen)) {
/*
* We process outgoing injected frames that have a
* local address we handle as though they are our
* own frames.
* This code here isn't entirely correct, the local
* MAC address is not necessarily enough to find
* the interface to use; for that proper VLAN/WDS
* support we will need a different mechanism.
*/
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces,
list) {
if (!netif_running(sdata->dev))
continue;
if (sdata->vif.type != NL80211_IFTYPE_AP)
continue;
if (compare_ether_addr(sdata->dev->dev_addr,
hdr->addr2)) {
dev_hold(sdata->dev);
dev_put(odev);
osdata = sdata;
odev = osdata->dev;
skb->iif = sdata->dev->ifindex;
monitor_iface = FOUND_SDATA;
break;
}
}
rcu_read_unlock();
}
}
may_encrypt = !skb->do_not_encrypt;
headroom = osdata->local->tx_headroom;
if (may_encrypt)
headroom += IEEE80211_ENCRYPT_HEADROOM;
headroom -= skb_headroom(skb);
headroom = max_t(int, 0, headroom);
if (ieee80211_skb_resize(osdata->local, skb, headroom, may_encrypt)) {
dev_kfree_skb(skb);
dev_put(odev);
return NETDEV_TX_OK;
}
if (osdata->vif.type == NL80211_IFTYPE_AP_VLAN)
osdata = container_of(osdata->bss,
struct ieee80211_sub_if_data,
u.ap);
if (likely(monitor_iface != UNKNOWN_ADDRESS))
info->control.vif = &osdata->vif;
ieee80211_tx(odev, skb, false);
dev_put(odev);
return NETDEV_TX_OK;
}
int ieee80211_monitor_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_channel *chan = local->hw.conf.channel;
struct ieee80211_radiotap_header *prthdr =
(struct ieee80211_radiotap_header *)skb->data;
u16 len_rthdr;
/*
* Frame injection is not allowed if beaconing is not allowed
* or if we need radar detection. Beaconing is usually not allowed when
* the mode or operation (Adhoc, AP, Mesh) does not support DFS.
* Passive scan is also used in world regulatory domains where
* your country is not known and as such it should be treated as
* NO TX unless the channel is explicitly allowed in which case
* your current regulatory domain would not have the passive scan
* flag.
*
* Since AP mode uses monitor interfaces to inject/TX management
* frames we can make AP mode the exception to this rule once it
* supports radar detection as its implementation can deal with
* radar detection by itself. We can do that later by adding a
* monitor flag interfaces used for AP support.
*/
if ((chan->flags & (IEEE80211_CHAN_NO_IBSS | IEEE80211_CHAN_RADAR |
IEEE80211_CHAN_PASSIVE_SCAN)))
goto fail;
/* 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;
/* needed because we set skb device to master */
skb->iif = dev->ifindex;
/* sometimes we do encrypt injected frames, will be fixed
* up in radiotap parser if not wanted */
skb->do_not_encrypt = 0;
/*
* 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_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_local *local = sdata->local;
int ret = 1, head_need;
u16 ethertype, hdrlen, meshhdrlen = 0;
__le16 fc;
struct ieee80211_hdr hdr;
struct ieee80211s_hdr mesh_hdr;
const u8 *encaps_data;
int encaps_len, skip_header_bytes;
int nh_pos, h_pos;
struct sta_info *sta;
u32 sta_flags = 0;
if (unlikely(skb->len < ETH_HLEN)) {
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];
fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
switch (sdata->vif.type) {
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_AP_VLAN:
fc |= cpu_to_le16(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 NL80211_IFTYPE_WDS:
fc |= cpu_to_le16(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;
#ifdef CONFIG_MAC80211_MESH
case NL80211_IFTYPE_MESH_POINT:
fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
if (!sdata->u.mesh.mshcfg.dot11MeshTTL) {
/* Do not send frames with mesh_ttl == 0 */
sdata->u.mesh.mshstats.dropped_frames_ttl++;
ret = 0;
goto fail;
}
memset(&mesh_hdr, 0, sizeof(mesh_hdr));
if (compare_ether_addr(dev->dev_addr,
skb->data + ETH_ALEN) == 0) {
/* RA TA DA SA */
memset(hdr.addr1, 0, 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);
meshhdrlen = ieee80211_new_mesh_header(&mesh_hdr, sdata);
} else {
/* packet from other interface */
struct mesh_path *mppath;
memset(hdr.addr1, 0, ETH_ALEN);
memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
memcpy(hdr.addr4, dev->dev_addr, ETH_ALEN);
if (is_multicast_ether_addr(skb->data))
memcpy(hdr.addr3, skb->data, ETH_ALEN);
else {
rcu_read_lock();
mppath = mpp_path_lookup(skb->data, sdata);
if (mppath)
memcpy(hdr.addr3, mppath->mpp, ETH_ALEN);
else
memset(hdr.addr3, 0xff, ETH_ALEN);
rcu_read_unlock();
}
mesh_hdr.flags |= MESH_FLAGS_AE_A5_A6;
mesh_hdr.ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
put_unaligned(cpu_to_le32(sdata->u.mesh.mesh_seqnum), &mesh_hdr.seqnum);
memcpy(mesh_hdr.eaddr1, skb->data, ETH_ALEN);
memcpy(mesh_hdr.eaddr2, skb->data + ETH_ALEN, ETH_ALEN);
sdata->u.mesh.mesh_seqnum++;
meshhdrlen = 18;
}
hdrlen = 30;
break;
#endif
case NL80211_IFTYPE_STATION:
fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
/* BSSID SA DA */
memcpy(hdr.addr1, sdata->u.mgd.bssid, ETH_ALEN);
memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
memcpy(hdr.addr3, skb->data, ETH_ALEN);
hdrlen = 24;
break;
case NL80211_IFTYPE_ADHOC:
/* DA SA BSSID */
memcpy(hdr.addr1, skb->data, ETH_ALEN);
memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
memcpy(hdr.addr3, sdata->u.ibss.bssid, ETH_ALEN);
hdrlen = 24;
break;
default:
ret = 0;
goto fail;
}
/*
* There's no need to try to look up the destination
* if it is a multicast address (which can only happen
* in AP mode)
*/
if (!is_multicast_ether_addr(hdr.addr1)) {
rcu_read_lock();
sta = sta_info_get(local, hdr.addr1);
if (sta)
sta_flags = get_sta_flags(sta);
rcu_read_unlock();
}
/* receiver and we are QoS enabled, use a QoS type frame */
if ((sta_flags & WLAN_STA_WME) && local->hw.queues >= 4) {
fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
hdrlen += 2;
}
/*
* Drop unicast frames to unauthorised stations unless they are
* EAPOL frames from the local station.
*/
if (!ieee80211_vif_is_mesh(&sdata->vif) &&
unlikely(!is_multicast_ether_addr(hdr.addr1) &&
!(sta_flags & WLAN_STA_AUTHORIZED) &&
!(ethertype == ETH_P_PAE &&
compare_ether_addr(dev->dev_addr,
skb->data + ETH_ALEN) == 0))) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
if (net_ratelimit())
printk(KERN_DEBUG "%s: dropped frame to %pM"
" (unauthorized port)\n", dev->name,
hdr.addr1);
#endif
I802_DEBUG_INC(local->tx_handlers_drop_unauth_port);
ret = 0;
goto fail;
}
hdr.frame_control = 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;
head_need = hdrlen + encaps_len + meshhdrlen - skb_headroom(skb);
/*
* So we need to modify the skb header and hence need a copy of
* that. The head_need variable above doesn't, so far, include
* the needed header space that we don't need right away. If we
* can, then we don't reallocate right now but only after the
* frame arrives at the master device (if it does...)
*
* If we cannot, however, then we will reallocate to include all
* the ever needed space. Also, if we need to reallocate it anyway,
* make it big enough for everything we may ever need.
*/
if (head_need > 0 || skb_cloned(skb)) {
head_need += IEEE80211_ENCRYPT_HEADROOM;
head_need += local->tx_headroom;
head_need = max_t(int, 0, head_need);
if (ieee80211_skb_resize(local, skb, head_need, true))
goto fail;
}
if (encaps_data) {
memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
nh_pos += encaps_len;
h_pos += encaps_len;
}
if (meshhdrlen > 0) {
memcpy(skb_push(skb, meshhdrlen), &mesh_hdr, meshhdrlen);
nh_pos += meshhdrlen;
h_pos += meshhdrlen;
}
if (ieee80211_is_data_qos(fc)) {
__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;
skb->iif = dev->ifindex;
skb->dev = local->mdev;
dev->stats.tx_packets++;
dev->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;
}
/*
* ieee80211_clear_tx_pending may not be called in a context where
* it is possible that it packets could come in again.
*/
void ieee80211_clear_tx_pending(struct ieee80211_local *local)
{
int i;
for (i = 0; i < local->hw.queues; i++)
skb_queue_purge(&local->pending[i]);
}
static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
struct sk_buff *skb)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
struct ieee80211_hdr *hdr;
struct net_device *dev;
int ret;
bool result = true;
/* does interface still exist? */
dev = dev_get_by_index(&init_net, skb->iif);
if (!dev) {
dev_kfree_skb(skb);
return true;
}
/* validate info->control.vif against skb->iif */
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
sdata = container_of(sdata->bss,
struct ieee80211_sub_if_data,
u.ap);
if (unlikely(info->control.vif && info->control.vif != &sdata->vif)) {
dev_kfree_skb(skb);
result = true;
goto out;
}
if (info->flags & IEEE80211_TX_INTFL_NEED_TXPROCESSING) {
ieee80211_tx(dev, skb, true);
} else {
hdr = (struct ieee80211_hdr *)skb->data;
sta = sta_info_get(local, hdr->addr1);
ret = __ieee80211_tx(local, &skb, sta);
if (ret != IEEE80211_TX_OK)
result = false;
}
out:
dev_put(dev);
return result;
}
/*
* Transmit all pending packets. Called from tasklet, locks master device
* TX lock so that no new packets can come in.
*/
void ieee80211_tx_pending(unsigned long data)
{
struct ieee80211_local *local = (struct ieee80211_local *)data;
struct net_device *dev = local->mdev;
unsigned long flags;
int i;
bool next;
rcu_read_lock();
netif_tx_lock_bh(dev);
for (i = 0; i < local->hw.queues; i++) {
/*
* If queue is stopped by something other than due to pending
* frames, or we have no pending frames, proceed to next queue.
*/
spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
next = false;
if (local->queue_stop_reasons[i] !=
BIT(IEEE80211_QUEUE_STOP_REASON_PENDING) ||
skb_queue_empty(&local->pending[i]))
next = true;
spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
if (next)
continue;
/*
* start the queue now to allow processing our packets,
* we're under the tx lock here anyway so nothing will
* happen as a result of this
*/
netif_start_subqueue(local->mdev, i);
while (!skb_queue_empty(&local->pending[i])) {
struct sk_buff *skb = skb_dequeue(&local->pending[i]);
if (!ieee80211_tx_pending_skb(local, skb)) {
skb_queue_head(&local->pending[i], skb);
break;
}
}
/* Start regular packet processing again. */
if (skb_queue_empty(&local->pending[i]))
ieee80211_wake_queue_by_reason(&local->hw, i,
IEEE80211_QUEUE_STOP_REASON_PENDING);
}
netif_tx_unlock_bh(dev);
rcu_read_unlock();
}
/* functions for drivers to get certain frames */
static void ieee80211_beacon_add_tim(struct ieee80211_if_ap *bss,
struct sk_buff *skb,
struct beacon_data *beacon)
{
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. */
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 = beacon->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++ = beacon->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 */
}
}
struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
struct ieee80211_vif *vif)
{
struct ieee80211_local *local = hw_to_local(hw);
struct sk_buff *skb = NULL;
struct ieee80211_tx_info *info;
struct ieee80211_sub_if_data *sdata = NULL;
struct ieee80211_if_ap *ap = NULL;
struct beacon_data *beacon;
struct ieee80211_supported_band *sband;
enum ieee80211_band band = local->hw.conf.channel->band;
sband = local->hw.wiphy->bands[band];
rcu_read_lock();
sdata = vif_to_sdata(vif);
if (sdata->vif.type == NL80211_IFTYPE_AP) {
ap = &sdata->u.ap;
beacon = rcu_dereference(ap->beacon);
if (ap && beacon) {
/*
* headroom, head length,
* tail length and maximum TIM length
*/
skb = dev_alloc_skb(local->tx_headroom +
beacon->head_len +
beacon->tail_len + 256);
if (!skb)
goto out;
skb_reserve(skb, local->tx_headroom);
memcpy(skb_put(skb, beacon->head_len), beacon->head,
beacon->head_len);
/*
* Not very nice, but we want to allow the driver to call
* ieee80211_beacon_get() as a response to the set_tim()
* callback. That, however, is already invoked under the
* sta_lock to guarantee consistent and race-free update
* of the tim bitmap in mac80211 and the driver.
*/
if (local->tim_in_locked_section) {
ieee80211_beacon_add_tim(ap, skb, beacon);
} else {
unsigned long flags;
spin_lock_irqsave(&local->sta_lock, flags);
ieee80211_beacon_add_tim(ap, skb, beacon);
spin_unlock_irqrestore(&local->sta_lock, flags);
}
if (beacon->tail)
memcpy(skb_put(skb, beacon->tail_len),
beacon->tail, beacon->tail_len);
} else
goto out;
} else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
struct ieee80211_hdr *hdr;
if (!ifibss->probe_resp)
goto out;
skb = skb_copy(ifibss->probe_resp, GFP_ATOMIC);
if (!skb)
goto out;
hdr = (struct ieee80211_hdr *) skb->data;
hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_BEACON);
} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
struct ieee80211_mgmt *mgmt;
u8 *pos;
/* headroom, head length, tail length and maximum TIM length */
skb = dev_alloc_skb(local->tx_headroom + 400);
if (!skb)
goto out;
skb_reserve(skb, local->hw.extra_tx_headroom);
mgmt = (struct ieee80211_mgmt *)
skb_put(skb, 24 + sizeof(mgmt->u.beacon));
memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
mgmt->frame_control =
cpu_to_le16(IEEE80211_FTYPE_MGMT | IEEE80211_STYPE_BEACON);
memset(mgmt->da, 0xff, ETH_ALEN);
memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
/* BSSID is left zeroed, wildcard value */
mgmt->u.beacon.beacon_int =
cpu_to_le16(local->hw.conf.beacon_int);
mgmt->u.beacon.capab_info = 0x0; /* 0x0 for MPs */
pos = skb_put(skb, 2);
*pos++ = WLAN_EID_SSID;
*pos++ = 0x0;
mesh_mgmt_ies_add(skb, sdata);
} else {
WARN_ON(1);
goto out;
}
info = IEEE80211_SKB_CB(skb);
skb->do_not_encrypt = 1;
info->band = band;
/*
* XXX: For now, always use the lowest rate
*/
info->control.rates[0].idx = 0;
info->control.rates[0].count = 1;
info->control.rates[1].idx = -1;
info->control.rates[2].idx = -1;
info->control.rates[3].idx = -1;
info->control.rates[4].idx = -1;
BUILD_BUG_ON(IEEE80211_TX_MAX_RATES != 5);
info->control.vif = vif;
info->flags |= IEEE80211_TX_CTL_NO_ACK;
info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
out:
rcu_read_unlock();
return skb;
}
EXPORT_SYMBOL(ieee80211_beacon_get);
void ieee80211_rts_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
const void *frame, size_t frame_len,
const struct ieee80211_tx_info *frame_txctl,
struct ieee80211_rts *rts)
{
const struct ieee80211_hdr *hdr = frame;
rts->frame_control =
cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS);
rts->duration = ieee80211_rts_duration(hw, vif, 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, struct ieee80211_vif *vif,
const void *frame, size_t frame_len,
const struct ieee80211_tx_info *frame_txctl,
struct ieee80211_cts *cts)
{
const struct ieee80211_hdr *hdr = frame;
cts->frame_control =
cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS);
cts->duration = ieee80211_ctstoself_duration(hw, vif,
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,
struct ieee80211_vif *vif)
{
struct ieee80211_local *local = hw_to_local(hw);
struct sk_buff *skb = NULL;
struct sta_info *sta;
struct ieee80211_tx_data tx;
struct ieee80211_sub_if_data *sdata;
struct ieee80211_if_ap *bss = NULL;
struct beacon_data *beacon;
struct ieee80211_tx_info *info;
sdata = vif_to_sdata(vif);
bss = &sdata->u.ap;
if (!bss)
return NULL;
rcu_read_lock();
beacon = rcu_dereference(bss->beacon);
if (sdata->vif.type != NL80211_IFTYPE_AP || !beacon || !beacon->head)
goto out;
if (bss->dtim_count != 0)
goto out; /* send buffered bc/mc only after DTIM beacon */
while (1) {
skb = skb_dequeue(&bss->ps_bc_buf);
if (!skb)
goto out;
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(local, &tx, skb))
break;
dev_kfree_skb_any(skb);
}
info = IEEE80211_SKB_CB(skb);
sta = tx.sta;
tx.flags |= IEEE80211_TX_PS_BUFFERED;
tx.channel = local->hw.conf.channel;
info->band = tx.channel->band;
if (invoke_tx_handlers(&tx))
skb = NULL;
out:
rcu_read_unlock();
return skb;
}
EXPORT_SYMBOL(ieee80211_get_buffered_bc);