linux/net/mac80211/rx.c

2684 lines
73 KiB
C
Raw Normal View History

/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007-2010 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.
*/
#include <linux/jiffies.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 09:04:11 +01:00
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.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 17:10:24 +02:00
#include <linux/rcupdate.h>
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "led.h"
#include "mesh.h"
#include "wep.h"
#include "wpa.h"
#include "tkip.h"
#include "wme.h"
/*
* monitor mode reception
*
* This function cleans up the SKB, i.e. it removes all the stuff
* only useful for monitoring.
*/
static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
struct sk_buff *skb)
{
if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
if (likely(skb->len > FCS_LEN))
__pskb_trim(skb, skb->len - FCS_LEN);
else {
/* driver bug */
WARN_ON(1);
dev_kfree_skb(skb);
skb = NULL;
}
}
return skb;
}
static inline int should_drop_frame(struct sk_buff *skb,
int present_fcs_len)
{
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
return 1;
if (unlikely(skb->len < 16 + present_fcs_len))
return 1;
if (ieee80211_is_ctl(hdr->frame_control) &&
!ieee80211_is_pspoll(hdr->frame_control) &&
!ieee80211_is_back_req(hdr->frame_control))
return 1;
return 0;
}
static int
ieee80211_rx_radiotap_len(struct ieee80211_local *local,
struct ieee80211_rx_status *status)
{
int len;
/* always present fields */
len = sizeof(struct ieee80211_radiotap_header) + 9;
if (status->flag & RX_FLAG_TSFT)
len += 8;
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
len += 1;
if (len & 1) /* padding for RX_FLAGS if necessary */
len++;
return len;
}
/*
* ieee80211_add_rx_radiotap_header - add radiotap header
*
* add a radiotap header containing all the fields which the hardware provided.
*/
static void
ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
struct sk_buff *skb,
struct ieee80211_rate *rate,
int rtap_len)
{
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_radiotap_header *rthdr;
unsigned char *pos;
u16 rx_flags = 0;
rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
memset(rthdr, 0, rtap_len);
/* radiotap header, set always present flags */
rthdr->it_present =
cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
(1 << IEEE80211_RADIOTAP_CHANNEL) |
(1 << IEEE80211_RADIOTAP_ANTENNA) |
(1 << IEEE80211_RADIOTAP_RX_FLAGS));
rthdr->it_len = cpu_to_le16(rtap_len);
pos = (unsigned char *)(rthdr+1);
/* the order of the following fields is important */
/* IEEE80211_RADIOTAP_TSFT */
if (status->flag & RX_FLAG_TSFT) {
put_unaligned_le64(status->mactime, pos);
rthdr->it_present |=
cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
pos += 8;
}
/* IEEE80211_RADIOTAP_FLAGS */
if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
*pos |= IEEE80211_RADIOTAP_F_FCS;
if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
*pos |= IEEE80211_RADIOTAP_F_BADFCS;
if (status->flag & RX_FLAG_SHORTPRE)
*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
pos++;
/* IEEE80211_RADIOTAP_RATE */
if (status->flag & RX_FLAG_HT) {
/*
* TODO: add following information into radiotap header once
* suitable fields are defined for it:
* - MCS index (status->rate_idx)
* - HT40 (status->flag & RX_FLAG_40MHZ)
* - short-GI (status->flag & RX_FLAG_SHORT_GI)
*/
*pos = 0;
} else {
rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
*pos = rate->bitrate / 5;
}
pos++;
/* IEEE80211_RADIOTAP_CHANNEL */
put_unaligned_le16(status->freq, pos);
pos += 2;
if (status->band == IEEE80211_BAND_5GHZ)
put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
pos);
else if (status->flag & RX_FLAG_HT)
put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
pos);
else if (rate->flags & IEEE80211_RATE_ERP_G)
put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
pos);
else
put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
pos);
pos += 2;
/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
*pos = status->signal;
rthdr->it_present |=
cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
pos++;
}
/* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */
/* IEEE80211_RADIOTAP_ANTENNA */
*pos = status->antenna;
pos++;
/* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */
/* IEEE80211_RADIOTAP_RX_FLAGS */
/* ensure 2 byte alignment for the 2 byte field as required */
if ((pos - (u8 *)rthdr) & 1)
pos++;
if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
put_unaligned_le16(rx_flags, pos);
pos += 2;
}
/*
* This function copies a received frame to all monitor interfaces and
* returns a cleaned-up SKB that no longer includes the FCS nor the
* radiotap header the driver might have added.
*/
static struct sk_buff *
ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
struct ieee80211_rate *rate)
{
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
struct ieee80211_sub_if_data *sdata;
int needed_headroom = 0;
struct sk_buff *skb, *skb2;
struct net_device *prev_dev = NULL;
int present_fcs_len = 0;
/*
* First, we may need to make a copy of the skb because
* (1) we need to modify it for radiotap (if not present), and
* (2) the other RX handlers will modify the skb we got.
*
* We don't need to, of course, if we aren't going to return
* the SKB because it has a bad FCS/PLCP checksum.
*/
/* room for the radiotap header based on driver features */
needed_headroom = ieee80211_rx_radiotap_len(local, status);
if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
present_fcs_len = FCS_LEN;
/* make sure hdr->frame_control is on the linear part */
if (!pskb_may_pull(origskb, 2)) {
dev_kfree_skb(origskb);
return NULL;
}
if (!local->monitors) {
if (should_drop_frame(origskb, present_fcs_len)) {
dev_kfree_skb(origskb);
return NULL;
}
return remove_monitor_info(local, origskb);
}
if (should_drop_frame(origskb, present_fcs_len)) {
/* only need to expand headroom if necessary */
skb = origskb;
origskb = NULL;
/*
* This shouldn't trigger often because most devices have an
* RX header they pull before we get here, and that should
* be big enough for our radiotap information. We should
* probably export the length to drivers so that we can have
* them allocate enough headroom to start with.
*/
if (skb_headroom(skb) < needed_headroom &&
pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
dev_kfree_skb(skb);
return NULL;
}
} else {
/*
* Need to make a copy and possibly remove radiotap header
* and FCS from the original.
*/
skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC);
origskb = remove_monitor_info(local, origskb);
if (!skb)
return origskb;
}
/* prepend radiotap information */
ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom);
skb_reset_mac_header(skb);
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->pkt_type = PACKET_OTHERHOST;
skb->protocol = htons(ETH_P_802_2);
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
continue;
if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
continue;
if (!ieee80211_sdata_running(sdata))
continue;
if (prev_dev) {
skb2 = skb_clone(skb, GFP_ATOMIC);
if (skb2) {
skb2->dev = prev_dev;
netif_receive_skb(skb2);
}
}
prev_dev = sdata->dev;
sdata->dev->stats.rx_packets++;
sdata->dev->stats.rx_bytes += skb->len;
}
if (prev_dev) {
skb->dev = prev_dev;
netif_receive_skb(skb);
} else
dev_kfree_skb(skb);
return origskb;
}
static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
int tid;
/* does the frame have a qos control field? */
if (ieee80211_is_data_qos(hdr->frame_control)) {
u8 *qc = ieee80211_get_qos_ctl(hdr);
/* frame has qos control */
tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
if (*qc & IEEE80211_QOS_CONTROL_A_MSDU_PRESENT)
rx->flags |= IEEE80211_RX_AMSDU;
else
rx->flags &= ~IEEE80211_RX_AMSDU;
} else {
/*
* IEEE 802.11-2007, 7.1.3.4.1 ("Sequence Number field"):
*
* Sequence numbers for management frames, QoS data
* frames with a broadcast/multicast address in the
* Address 1 field, and all non-QoS data frames sent
* by QoS STAs are assigned using an additional single
* modulo-4096 counter, [...]
*
* We also use that counter for non-QoS STAs.
*/
tid = NUM_RX_DATA_QUEUES - 1;
}
rx->queue = tid;
/* Set skb->priority to 1d tag if highest order bit of TID is not set.
* For now, set skb->priority to 0 for other cases. */
rx->skb->priority = (tid > 7) ? 0 : tid;
}
/**
* DOC: Packet alignment
*
* Drivers always need to pass packets that are aligned to two-byte boundaries
* to the stack.
*
* Additionally, should, if possible, align the payload data in a way that
* guarantees that the contained IP header is aligned to a four-byte
* boundary. In the case of regular frames, this simply means aligning the
* payload to a four-byte boundary (because either the IP header is directly
* contained, or IV/RFC1042 headers that have a length divisible by four are
* in front of it). If the payload data is not properly aligned and the
* architecture doesn't support efficient unaligned operations, mac80211
* will align the data.
*
* With A-MSDU frames, however, the payload data address must yield two modulo
* four because there are 14-byte 802.3 headers within the A-MSDU frames that
* push the IP header further back to a multiple of four again. Thankfully, the
* specs were sane enough this time around to require padding each A-MSDU
* subframe to a length that is a multiple of four.
*
* Padding like Atheros hardware adds which is inbetween the 802.11 header and
* the payload is not supported, the driver is required to move the 802.11
* header to be directly in front of the payload in that case.
*/
static void ieee80211_verify_alignment(struct ieee80211_rx_data *rx)
{
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
WARN_ONCE((unsigned long)rx->skb->data & 1,
"unaligned packet at 0x%p\n", rx->skb->data);
#endif
}
/* rx handlers */
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
{
struct ieee80211_local *local = rx->local;
struct sk_buff *skb = rx->skb;
if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning)))
return ieee80211_scan_rx(rx->sdata, skb);
mac80211: hardware scan rework The scan code in mac80211 makes the software scan assumption in various places. For example, we stop the Tx queue during a software scan so that all the Tx packets will be queued by the stack. We also drop frames not related to scan in the software scan process. But these are not true for hardware scan. Some wireless hardwares (for example iwl3945/4965) has the ability to perform the whole scan process by hardware and/or firmware. The hardware scan is relative powerful in that it tries to maintain normal network traffic while doing a scan in the background. Some drivers (i.e iwlwifi) do provide a way to tune the hardware scan parameters (for example if the STA is associated, what's the max time could the STA leave from the associated channel, how long the scans get suspended after returning to the service channel, etc). But basically this is transparent to the stack. mac80211 should not stop Tx queues or drop Rx packets during a hardware scan. This patch resolves the above problem by spliting the current scan indicator local->sta_scanning into local->sta_sw_scanning and local->sta_hw_scanning. It then changes the scan related code to be aware of hardware scan or software scan in various places. With this patch, iwlwifi performs much better in the scan-while-associated condition and disable_hw_scan=1 should never be required. Cc: Mohamed Abbas <mohamed.abbas@intel.com> Cc: Ben Cahill <ben.m.cahill@intel.com> Signed-off-by: Zhu Yi <yi.zhu@intel.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-22 03:53:21 +01:00
if (unlikely(test_bit(SCAN_SW_SCANNING, &local->scanning) &&
(rx->flags & IEEE80211_RX_IN_SCAN))) {
mac80211: hardware scan rework The scan code in mac80211 makes the software scan assumption in various places. For example, we stop the Tx queue during a software scan so that all the Tx packets will be queued by the stack. We also drop frames not related to scan in the software scan process. But these are not true for hardware scan. Some wireless hardwares (for example iwl3945/4965) has the ability to perform the whole scan process by hardware and/or firmware. The hardware scan is relative powerful in that it tries to maintain normal network traffic while doing a scan in the background. Some drivers (i.e iwlwifi) do provide a way to tune the hardware scan parameters (for example if the STA is associated, what's the max time could the STA leave from the associated channel, how long the scans get suspended after returning to the service channel, etc). But basically this is transparent to the stack. mac80211 should not stop Tx queues or drop Rx packets during a hardware scan. This patch resolves the above problem by spliting the current scan indicator local->sta_scanning into local->sta_sw_scanning and local->sta_hw_scanning. It then changes the scan related code to be aware of hardware scan or software scan in various places. With this patch, iwlwifi performs much better in the scan-while-associated condition and disable_hw_scan=1 should never be required. Cc: Mohamed Abbas <mohamed.abbas@intel.com> Cc: Ben Cahill <ben.m.cahill@intel.com> Signed-off-by: Zhu Yi <yi.zhu@intel.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-22 03:53:21 +01:00
/* drop all the other packets during a software scan anyway */
if (ieee80211_scan_rx(rx->sdata, skb) != RX_QUEUED)
mac80211: hardware scan rework The scan code in mac80211 makes the software scan assumption in various places. For example, we stop the Tx queue during a software scan so that all the Tx packets will be queued by the stack. We also drop frames not related to scan in the software scan process. But these are not true for hardware scan. Some wireless hardwares (for example iwl3945/4965) has the ability to perform the whole scan process by hardware and/or firmware. The hardware scan is relative powerful in that it tries to maintain normal network traffic while doing a scan in the background. Some drivers (i.e iwlwifi) do provide a way to tune the hardware scan parameters (for example if the STA is associated, what's the max time could the STA leave from the associated channel, how long the scans get suspended after returning to the service channel, etc). But basically this is transparent to the stack. mac80211 should not stop Tx queues or drop Rx packets during a hardware scan. This patch resolves the above problem by spliting the current scan indicator local->sta_scanning into local->sta_sw_scanning and local->sta_hw_scanning. It then changes the scan related code to be aware of hardware scan or software scan in various places. With this patch, iwlwifi performs much better in the scan-while-associated condition and disable_hw_scan=1 should never be required. Cc: Mohamed Abbas <mohamed.abbas@intel.com> Cc: Ben Cahill <ben.m.cahill@intel.com> Signed-off-by: Zhu Yi <yi.zhu@intel.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-22 03:53:21 +01:00
dev_kfree_skb(skb);
return RX_QUEUED;
}
if (unlikely(rx->flags & IEEE80211_RX_IN_SCAN)) {
/* scanning finished during invoking of handlers */
I802_DEBUG_INC(local->rx_handlers_drop_passive_scan);
return RX_DROP_UNUSABLE;
}
return RX_CONTINUE;
}
static int ieee80211_is_unicast_robust_mgmt_frame(struct sk_buff *skb)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
if (skb->len < 24 || is_multicast_ether_addr(hdr->addr1))
return 0;
return ieee80211_is_robust_mgmt_frame(hdr);
}
static int ieee80211_is_multicast_robust_mgmt_frame(struct sk_buff *skb)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
if (skb->len < 24 || !is_multicast_ether_addr(hdr->addr1))
return 0;
return ieee80211_is_robust_mgmt_frame(hdr);
}
/* Get the BIP key index from MMIE; return -1 if this is not a BIP frame */
static int ieee80211_get_mmie_keyidx(struct sk_buff *skb)
{
struct ieee80211_mgmt *hdr = (struct ieee80211_mgmt *) skb->data;
struct ieee80211_mmie *mmie;
if (skb->len < 24 + sizeof(*mmie) ||
!is_multicast_ether_addr(hdr->da))
return -1;
if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *) hdr))
return -1; /* not a robust management frame */
mmie = (struct ieee80211_mmie *)
(skb->data + skb->len - sizeof(*mmie));
if (mmie->element_id != WLAN_EID_MMIE ||
mmie->length != sizeof(*mmie) - 2)
return -1;
return le16_to_cpu(mmie->key_id);
}
static ieee80211_rx_result
ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
unsigned int hdrlen = ieee80211_hdrlen(hdr->frame_control);
char *dev_addr = rx->sdata->vif.addr;
if (ieee80211_is_data(hdr->frame_control)) {
if (is_multicast_ether_addr(hdr->addr1)) {
if (ieee80211_has_tods(hdr->frame_control) ||
!ieee80211_has_fromds(hdr->frame_control))
return RX_DROP_MONITOR;
if (memcmp(hdr->addr3, dev_addr, ETH_ALEN) == 0)
return RX_DROP_MONITOR;
} else {
if (!ieee80211_has_a4(hdr->frame_control))
return RX_DROP_MONITOR;
if (memcmp(hdr->addr4, dev_addr, ETH_ALEN) == 0)
return RX_DROP_MONITOR;
}
}
/* If there is not an established peer link and this is not a peer link
* establisment frame, beacon or probe, drop the frame.
*/
if (!rx->sta || sta_plink_state(rx->sta) != PLINK_ESTAB) {
struct ieee80211_mgmt *mgmt;
if (!ieee80211_is_mgmt(hdr->frame_control))
return RX_DROP_MONITOR;
if (ieee80211_is_action(hdr->frame_control)) {
mgmt = (struct ieee80211_mgmt *)hdr;
if (mgmt->u.action.category != WLAN_CATEGORY_MESH_PLINK)
return RX_DROP_MONITOR;
return RX_CONTINUE;
}
if (ieee80211_is_probe_req(hdr->frame_control) ||
ieee80211_is_probe_resp(hdr->frame_control) ||
ieee80211_is_beacon(hdr->frame_control))
return RX_CONTINUE;
return RX_DROP_MONITOR;
}
#define msh_h_get(h, l) ((struct ieee80211s_hdr *) ((u8 *)h + l))
if (ieee80211_is_data(hdr->frame_control) &&
is_multicast_ether_addr(hdr->addr1) &&
mesh_rmc_check(hdr->addr3, msh_h_get(hdr, hdrlen), rx->sdata))
return RX_DROP_MONITOR;
#undef msh_h_get
return RX_CONTINUE;
}
#define SEQ_MODULO 0x1000
#define SEQ_MASK 0xfff
static inline int seq_less(u16 sq1, u16 sq2)
{
return ((sq1 - sq2) & SEQ_MASK) > (SEQ_MODULO >> 1);
}
static inline u16 seq_inc(u16 sq)
{
return (sq + 1) & SEQ_MASK;
}
static inline u16 seq_sub(u16 sq1, u16 sq2)
{
return (sq1 - sq2) & SEQ_MASK;
}
static void ieee80211_release_reorder_frame(struct ieee80211_hw *hw,
struct tid_ampdu_rx *tid_agg_rx,
int index,
struct sk_buff_head *frames)
{
struct ieee80211_supported_band *sband;
struct ieee80211_rate *rate = NULL;
struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
struct ieee80211_rx_status *status;
if (!skb)
goto no_frame;
status = IEEE80211_SKB_RXCB(skb);
/* release the reordered frames to stack */
sband = hw->wiphy->bands[status->band];
if (!(status->flag & RX_FLAG_HT))
rate = &sband->bitrates[status->rate_idx];
tid_agg_rx->stored_mpdu_num--;
tid_agg_rx->reorder_buf[index] = NULL;
__skb_queue_tail(frames, skb);
no_frame:
tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
}
static void ieee80211_release_reorder_frames(struct ieee80211_hw *hw,
struct tid_ampdu_rx *tid_agg_rx,
u16 head_seq_num,
struct sk_buff_head *frames)
{
int index;
while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) {
index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
tid_agg_rx->buf_size;
ieee80211_release_reorder_frame(hw, tid_agg_rx, index, frames);
}
}
/*
* Timeout (in jiffies) for skb's that are waiting in the RX reorder buffer. If
* the skb was added to the buffer longer than this time ago, the earlier
* frames that have not yet been received are assumed to be lost and the skb
* can be released for processing. This may also release other skb's from the
* reorder buffer if there are no additional gaps between the frames.
*/
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)
/*
* As this function belongs to the RX path it must be under
* rcu_read_lock protection. It returns false if the frame
* can be processed immediately, true if it was consumed.
*/
static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
struct tid_ampdu_rx *tid_agg_rx,
struct sk_buff *skb,
struct sk_buff_head *frames)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
u16 sc = le16_to_cpu(hdr->seq_ctrl);
u16 mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4;
u16 head_seq_num, buf_size;
int index;
buf_size = tid_agg_rx->buf_size;
head_seq_num = tid_agg_rx->head_seq_num;
/* frame with out of date sequence number */
if (seq_less(mpdu_seq_num, head_seq_num)) {
dev_kfree_skb(skb);
return true;
}
/*
* If frame the sequence number exceeds our buffering window
* size release some previous frames to make room for this one.
*/
if (!seq_less(mpdu_seq_num, head_seq_num + buf_size)) {
head_seq_num = seq_inc(seq_sub(mpdu_seq_num, buf_size));
/* release stored frames up to new head to stack */
ieee80211_release_reorder_frames(hw, tid_agg_rx, head_seq_num,
frames);
}
/* Now the new frame is always in the range of the reordering buffer */
index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn) % tid_agg_rx->buf_size;
/* check if we already stored this frame */
if (tid_agg_rx->reorder_buf[index]) {
dev_kfree_skb(skb);
return true;
}
/*
* If the current MPDU is in the right order and nothing else
* is stored we can process it directly, no need to buffer it.
*/
if (mpdu_seq_num == tid_agg_rx->head_seq_num &&
tid_agg_rx->stored_mpdu_num == 0) {
tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
return false;
}
/* put the frame in the reordering buffer */
tid_agg_rx->reorder_buf[index] = skb;
tid_agg_rx->reorder_time[index] = jiffies;
tid_agg_rx->stored_mpdu_num++;
/* release the buffer until next missing frame */
index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
tid_agg_rx->buf_size;
if (!tid_agg_rx->reorder_buf[index] &&
tid_agg_rx->stored_mpdu_num > 1) {
/*
* No buffers ready to be released, but check whether any
* frames in the reorder buffer have timed out.
*/
int j;
int skipped = 1;
for (j = (index + 1) % tid_agg_rx->buf_size; j != index;
j = (j + 1) % tid_agg_rx->buf_size) {
if (!tid_agg_rx->reorder_buf[j]) {
skipped++;
continue;
}
if (!time_after(jiffies, tid_agg_rx->reorder_time[j] +
HT_RX_REORDER_BUF_TIMEOUT))
break;
#ifdef CONFIG_MAC80211_HT_DEBUG
if (net_ratelimit())
printk(KERN_DEBUG "%s: release an RX reorder "
"frame due to timeout on earlier "
"frames\n",
wiphy_name(hw->wiphy));
#endif
ieee80211_release_reorder_frame(hw, tid_agg_rx,
j, frames);
/*
* Increment the head seq# also for the skipped slots.
*/
tid_agg_rx->head_seq_num =
(tid_agg_rx->head_seq_num + skipped) & SEQ_MASK;
skipped = 0;
}
} else while (tid_agg_rx->reorder_buf[index]) {
ieee80211_release_reorder_frame(hw, tid_agg_rx, index, frames);
index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
tid_agg_rx->buf_size;
}
return true;
}
/*
* Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
* true if the MPDU was buffered, false if it should be processed.
*/
static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
struct sk_buff_head *frames)
{
struct sk_buff *skb = rx->skb;
struct ieee80211_local *local = rx->local;
struct ieee80211_hw *hw = &local->hw;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct sta_info *sta = rx->sta;
struct tid_ampdu_rx *tid_agg_rx;
u16 sc;
int tid;
if (!ieee80211_is_data_qos(hdr->frame_control))
goto dont_reorder;
/*
* filter the QoS data rx stream according to
* STA/TID and check if this STA/TID is on aggregation
*/
if (!sta)
goto dont_reorder;
tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
if (!tid_agg_rx)
goto dont_reorder;
/* qos null data frames are excluded */
if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
goto dont_reorder;
/* new, potentially un-ordered, ampdu frame - process it */
/* reset session timer */
if (tid_agg_rx->timeout)
mod_timer(&tid_agg_rx->session_timer,
TU_TO_EXP_TIME(tid_agg_rx->timeout));
/* if this mpdu is fragmented - terminate rx aggregation session */
sc = le16_to_cpu(hdr->seq_ctrl);
if (sc & IEEE80211_SCTL_FRAG) {
skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
skb_queue_tail(&rx->sdata->skb_queue, skb);
ieee80211_queue_work(&local->hw, &rx->sdata->work);
return;
}
/*
* No locking needed -- we will only ever process one
* RX packet at a time, and thus own tid_agg_rx. All
* other code manipulating it needs to (and does) make
* sure that we cannot get to it any more before doing
* anything with it.
*/
if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, frames))
return;
dont_reorder:
__skb_queue_tail(frames, skb);
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
rx->sta->last_seq_ctrl[rx->queue] ==
hdr->seq_ctrl)) {
if (rx->flags & IEEE80211_RX_RA_MATCH) {
rx->local->dot11FrameDuplicateCount++;
rx->sta->num_duplicates++;
}
return RX_DROP_MONITOR;
} else
rx->sta->last_seq_ctrl[rx->queue] = hdr->seq_ctrl;
}
if (unlikely(rx->skb->len < 16)) {
I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
return RX_DROP_MONITOR;
}
/* Drop disallowed frame classes based on STA auth/assoc state;
* IEEE 802.11, Chap 5.5.
*
* mac80211 filters only based on association state, i.e. it drops
* Class 3 frames from not associated stations. hostapd sends
* deauth/disassoc frames when needed. In addition, hostapd is
* responsible for filtering on both auth and assoc states.
*/
if (ieee80211_vif_is_mesh(&rx->sdata->vif))
return ieee80211_rx_mesh_check(rx);
if (unlikely((ieee80211_is_data(hdr->frame_control) ||
ieee80211_is_pspoll(hdr->frame_control)) &&
rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
(!rx->sta || !test_sta_flags(rx->sta, WLAN_STA_ASSOC)))) {
if ((!ieee80211_has_fromds(hdr->frame_control) &&
!ieee80211_has_tods(hdr->frame_control) &&
ieee80211_is_data(hdr->frame_control)) ||
!(rx->flags & IEEE80211_RX_RA_MATCH)) {
/* Drop IBSS frames and frames for other hosts
* silently. */
return RX_DROP_MONITOR;
}
return RX_DROP_MONITOR;
}
return RX_CONTINUE;
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
{
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
int keyidx;
int hdrlen;
ieee80211_rx_result result = RX_DROP_UNUSABLE;
[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 17:10:24 +02:00
struct ieee80211_key *stakey = NULL;
int mmie_keyidx = -1;
__le16 fc;
/*
* Key selection 101
*
* There are four types of keys:
* - GTK (group keys)
* - IGTK (group keys for management frames)
* - PTK (pairwise keys)
* - STK (station-to-station pairwise keys)
*
* When selecting a key, we have to distinguish between multicast
* (including broadcast) and unicast frames, the latter can only
* use PTKs and STKs while the former always use GTKs and IGTKs.
* Unless, of course, actual WEP keys ("pre-RSNA") are used, then
* unicast frames can also use key indices like GTKs. Hence, if we
* don't have a PTK/STK we check the key index for a WEP key.
*
* Note that in a regular BSS, multicast frames are sent by the
* AP only, associated stations unicast the frame to the AP first
* which then multicasts it on their behalf.
*
* There is also a slight problem in IBSS mode: GTKs are negotiated
* with each station, that is something we don't currently handle.
* The spec seems to expect that one negotiates the same key with
* every station but there's no such requirement; VLANs could be
* possible.
*/
/*
* No point in finding a key and decrypting if the frame is neither
* addressed to us nor a multicast frame.
*/
if (!(rx->flags & IEEE80211_RX_RA_MATCH))
return RX_CONTINUE;
/* start without a key */
rx->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 17:10:24 +02:00
if (rx->sta)
stakey = rcu_dereference(rx->sta->key);
fc = hdr->frame_control;
if (!ieee80211_has_protected(fc))
mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);
[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 17:10:24 +02:00
if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
rx->key = stakey;
/* Skip decryption if the frame is not protected. */
if (!ieee80211_has_protected(fc))
return RX_CONTINUE;
} else if (mmie_keyidx >= 0) {
/* Broadcast/multicast robust management frame / BIP */
if ((status->flag & RX_FLAG_DECRYPTED) &&
(status->flag & RX_FLAG_IV_STRIPPED))
return RX_CONTINUE;
if (mmie_keyidx < NUM_DEFAULT_KEYS ||
mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
return RX_DROP_MONITOR; /* unexpected BIP keyidx */
rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
} else if (!ieee80211_has_protected(fc)) {
/*
* The frame was not protected, so skip decryption. However, we
* need to set rx->key if there is a key that could have been
* used so that the frame may be dropped if encryption would
* have been expected.
*/
struct ieee80211_key *key = NULL;
if (ieee80211_is_mgmt(fc) &&
is_multicast_ether_addr(hdr->addr1) &&
(key = rcu_dereference(rx->sdata->default_mgmt_key)))
rx->key = key;
else if ((key = rcu_dereference(rx->sdata->default_key)))
rx->key = key;
return RX_CONTINUE;
} else {
u8 keyid;
/*
* The device doesn't give us the IV so we won't be
* able to look up the key. That's ok though, we
* don't need to decrypt the frame, we just won't
* be able to keep statistics accurate.
* Except for key threshold notifications, should
* we somehow allow the driver to tell us which key
* the hardware used if this flag is set?
*/
if ((status->flag & RX_FLAG_DECRYPTED) &&
(status->flag & RX_FLAG_IV_STRIPPED))
return RX_CONTINUE;
hdrlen = ieee80211_hdrlen(fc);
if (rx->skb->len < 8 + hdrlen)
return RX_DROP_UNUSABLE; /* TODO: count this? */
/*
* no need to call ieee80211_wep_get_keyidx,
* it verifies a bunch of things we've done already
*/
skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1);
keyidx = keyid >> 6;
[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 17:10:24 +02:00
rx->key = rcu_dereference(rx->sdata->keys[keyidx]);
/*
* RSNA-protected unicast frames should always be sent with
* pairwise or station-to-station keys, but for WEP we allow
* using a key index as well.
*/
if (rx->key && rx->key->conf.alg != ALG_WEP &&
!is_multicast_ether_addr(hdr->addr1))
rx->key = NULL;
}
if (rx->key) {
rx->key->tx_rx_count++;
/* TODO: add threshold stuff again */
} else {
return RX_DROP_MONITOR;
}
if (skb_linearize(rx->skb))
return RX_DROP_UNUSABLE;
/* the hdr variable is invalid now! */
switch (rx->key->conf.alg) {
case ALG_WEP:
/* Check for weak IVs if possible */
if (rx->sta && ieee80211_is_data(fc) &&
(!(status->flag & RX_FLAG_IV_STRIPPED) ||
!(status->flag & RX_FLAG_DECRYPTED)) &&
ieee80211_wep_is_weak_iv(rx->skb, rx->key))
rx->sta->wep_weak_iv_count++;
result = ieee80211_crypto_wep_decrypt(rx);
break;
case ALG_TKIP:
result = ieee80211_crypto_tkip_decrypt(rx);
break;
case ALG_CCMP:
result = ieee80211_crypto_ccmp_decrypt(rx);
break;
case ALG_AES_CMAC:
result = ieee80211_crypto_aes_cmac_decrypt(rx);
break;
}
/* either the frame has been decrypted or will be dropped */
status->flag |= RX_FLAG_DECRYPTED;
return result;
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_check_more_data(struct ieee80211_rx_data *rx)
{
struct ieee80211_local *local;
struct ieee80211_hdr *hdr;
struct sk_buff *skb;
local = rx->local;
skb = rx->skb;
hdr = (struct ieee80211_hdr *) skb->data;
if (!local->pspolling)
return RX_CONTINUE;
if (!ieee80211_has_fromds(hdr->frame_control))
/* this is not from AP */
return RX_CONTINUE;
if (!ieee80211_is_data(hdr->frame_control))
return RX_CONTINUE;
if (!ieee80211_has_moredata(hdr->frame_control)) {
/* AP has no more frames buffered for us */
local->pspolling = false;
return RX_CONTINUE;
}
/* more data bit is set, let's request a new frame from the AP */
ieee80211_send_pspoll(local, rx->sdata);
return RX_CONTINUE;
}
static void ap_sta_ps_start(struct sta_info *sta)
{
struct ieee80211_sub_if_data *sdata = sta->sdata;
struct ieee80211_local *local = sdata->local;
atomic_inc(&sdata->bss->num_sta_ps);
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
set_sta_flags(sta, WLAN_STA_PS_STA);
drv_sta_notify(local, sdata, STA_NOTIFY_SLEEP, &sta->sta);
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "%s: STA %pM aid %d enters power save mode\n",
sdata->name, sta->sta.addr, sta->sta.aid);
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
}
static void ap_sta_ps_end(struct sta_info *sta)
{
struct ieee80211_sub_if_data *sdata = sta->sdata;
atomic_dec(&sdata->bss->num_sta_ps);
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
clear_sta_flags(sta, WLAN_STA_PS_STA);
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
printk(KERN_DEBUG "%s: STA %pM aid %d exits power save mode\n",
sdata->name, sta->sta.addr, sta->sta.aid);
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
if (test_sta_flags(sta, WLAN_STA_PS_DRIVER)) {
#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
printk(KERN_DEBUG "%s: STA %pM aid %d driver-ps-blocked\n",
sdata->name, sta->sta.addr, sta->sta.aid);
#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
return;
}
ieee80211_sta_ps_deliver_wakeup(sta);
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
{
struct sta_info *sta = rx->sta;
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
if (!sta)
return RX_CONTINUE;
/*
* Update last_rx only for IBSS packets which are for the current
* BSSID to avoid keeping the current IBSS network alive in cases
* where other STAs start using different BSSID.
*/
if (rx->sdata->vif.type == NL80211_IFTYPE_ADHOC) {
u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len,
NL80211_IFTYPE_ADHOC);
if (compare_ether_addr(bssid, rx->sdata->u.ibss.bssid) == 0)
sta->last_rx = jiffies;
} else if (!is_multicast_ether_addr(hdr->addr1)) {
/*
* Mesh beacons will update last_rx when if they are found to
* match the current local configuration when processed.
*/
sta->last_rx = jiffies;
}
if (!(rx->flags & IEEE80211_RX_RA_MATCH))
return RX_CONTINUE;
if (rx->sdata->vif.type == NL80211_IFTYPE_STATION)
ieee80211_sta_rx_notify(rx->sdata, hdr);
sta->rx_fragments++;
sta->rx_bytes += rx->skb->len;
sta->last_signal = status->signal;
/*
* Change STA power saving mode only at the end of a frame
* exchange sequence.
*/
if (!ieee80211_has_morefrags(hdr->frame_control) &&
(rx->sdata->vif.type == NL80211_IFTYPE_AP ||
rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)) {
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
if (test_sta_flags(sta, WLAN_STA_PS_STA)) {
/*
* Ignore doze->wake transitions that are
* indicated by non-data frames, the standard
* is unclear here, but for example going to
* PS mode and then scanning would cause a
* doze->wake transition for the probe request,
* and that is clearly undesirable.
*/
if (ieee80211_is_data(hdr->frame_control) &&
!ieee80211_has_pm(hdr->frame_control))
ap_sta_ps_end(sta);
} else {
if (ieee80211_has_pm(hdr->frame_control))
ap_sta_ps_start(sta);
}
}
/*
* Drop (qos-)data::nullfunc frames silently, since they
* are used only to control station power saving mode.
*/
if (ieee80211_is_nullfunc(hdr->frame_control) ||
ieee80211_is_qos_nullfunc(hdr->frame_control)) {
I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
/*
* If we receive a 4-addr nullfunc frame from a STA
* that was not moved to a 4-addr STA vlan yet, drop
* the frame to the monitor interface, to make sure
* that hostapd sees it
*/
if (ieee80211_has_a4(hdr->frame_control) &&
(rx->sdata->vif.type == NL80211_IFTYPE_AP ||
(rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
!rx->sdata->u.vlan.sta)))
return RX_DROP_MONITOR;
/*
* Update counter and free packet here to avoid
* counting this as a dropped packed.
*/
sta->rx_packets++;
dev_kfree_skb(rx->skb);
return RX_QUEUED;
}
return RX_CONTINUE;
} /* ieee80211_rx_h_sta_process */
static inline struct ieee80211_fragment_entry *
ieee80211_reassemble_add(struct ieee80211_sub_if_data *sdata,
unsigned int frag, unsigned int seq, int rx_queue,
struct sk_buff **skb)
{
struct ieee80211_fragment_entry *entry;
int idx;
idx = sdata->fragment_next;
entry = &sdata->fragments[sdata->fragment_next++];
if (sdata->fragment_next >= IEEE80211_FRAGMENT_MAX)
sdata->fragment_next = 0;
if (!skb_queue_empty(&entry->skb_list)) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
struct ieee80211_hdr *hdr =
(struct ieee80211_hdr *) entry->skb_list.next->data;
printk(KERN_DEBUG "%s: RX reassembly removed oldest "
"fragment entry (idx=%d age=%lu seq=%d last_frag=%d "
"addr1=%pM addr2=%pM\n",
sdata->name, idx,
jiffies - entry->first_frag_time, entry->seq,
entry->last_frag, hdr->addr1, hdr->addr2);
#endif
__skb_queue_purge(&entry->skb_list);
}
__skb_queue_tail(&entry->skb_list, *skb); /* no need for locking */
*skb = NULL;
entry->first_frag_time = jiffies;
entry->seq = seq;
entry->rx_queue = rx_queue;
entry->last_frag = frag;
entry->ccmp = 0;
entry->extra_len = 0;
return entry;
}
static inline struct ieee80211_fragment_entry *
ieee80211_reassemble_find(struct ieee80211_sub_if_data *sdata,
unsigned int frag, unsigned int seq,
int rx_queue, struct ieee80211_hdr *hdr)
{
struct ieee80211_fragment_entry *entry;
int i, idx;
idx = sdata->fragment_next;
for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++) {
struct ieee80211_hdr *f_hdr;
idx--;
if (idx < 0)
idx = IEEE80211_FRAGMENT_MAX - 1;
entry = &sdata->fragments[idx];
if (skb_queue_empty(&entry->skb_list) || entry->seq != seq ||
entry->rx_queue != rx_queue ||
entry->last_frag + 1 != frag)
continue;
f_hdr = (struct ieee80211_hdr *)entry->skb_list.next->data;
/*
* Check ftype and addresses are equal, else check next fragment
*/
if (((hdr->frame_control ^ f_hdr->frame_control) &
cpu_to_le16(IEEE80211_FCTL_FTYPE)) ||
compare_ether_addr(hdr->addr1, f_hdr->addr1) != 0 ||
compare_ether_addr(hdr->addr2, f_hdr->addr2) != 0)
continue;
if (time_after(jiffies, entry->first_frag_time + 2 * HZ)) {
__skb_queue_purge(&entry->skb_list);
continue;
}
return entry;
}
return NULL;
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr;
u16 sc;
__le16 fc;
unsigned int frag, seq;
struct ieee80211_fragment_entry *entry;
struct sk_buff *skb;
hdr = (struct ieee80211_hdr *)rx->skb->data;
fc = hdr->frame_control;
sc = le16_to_cpu(hdr->seq_ctrl);
frag = sc & IEEE80211_SCTL_FRAG;
if (likely((!ieee80211_has_morefrags(fc) && frag == 0) ||
(rx->skb)->len < 24 ||
is_multicast_ether_addr(hdr->addr1))) {
/* not fragmented */
goto out;
}
I802_DEBUG_INC(rx->local->rx_handlers_fragments);
if (skb_linearize(rx->skb))
return RX_DROP_UNUSABLE;
/*
* skb_linearize() might change the skb->data and
* previously cached variables (in this case, hdr) need to
* be refreshed with the new data.
*/
hdr = (struct ieee80211_hdr *)rx->skb->data;
seq = (sc & IEEE80211_SCTL_SEQ) >> 4;
if (frag == 0) {
/* This is the first fragment of a new frame. */
entry = ieee80211_reassemble_add(rx->sdata, frag, seq,
rx->queue, &(rx->skb));
if (rx->key && rx->key->conf.alg == ALG_CCMP &&
ieee80211_has_protected(fc)) {
int queue = ieee80211_is_mgmt(fc) ?
NUM_RX_DATA_QUEUES : rx->queue;
/* Store CCMP PN so that we can verify that the next
* fragment has a sequential PN value. */
entry->ccmp = 1;
memcpy(entry->last_pn,
rx->key->u.ccmp.rx_pn[queue],
CCMP_PN_LEN);
}
return RX_QUEUED;
}
/* This is a fragment for a frame that should already be pending in
* fragment cache. Add this fragment to the end of the pending entry.
*/
entry = ieee80211_reassemble_find(rx->sdata, frag, seq, rx->queue, hdr);
if (!entry) {
I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
return RX_DROP_MONITOR;
}
/* Verify that MPDUs within one MSDU have sequential PN values.
* (IEEE 802.11i, 8.3.3.4.5) */
if (entry->ccmp) {
int i;
u8 pn[CCMP_PN_LEN], *rpn;
int queue;
if (!rx->key || rx->key->conf.alg != ALG_CCMP)
return RX_DROP_UNUSABLE;
memcpy(pn, entry->last_pn, CCMP_PN_LEN);
for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
pn[i]++;
if (pn[i])
break;
}
queue = ieee80211_is_mgmt(fc) ?
NUM_RX_DATA_QUEUES : rx->queue;
rpn = rx->key->u.ccmp.rx_pn[queue];
if (memcmp(pn, rpn, CCMP_PN_LEN))
return RX_DROP_UNUSABLE;
memcpy(entry->last_pn, pn, CCMP_PN_LEN);
}
skb_pull(rx->skb, ieee80211_hdrlen(fc));
__skb_queue_tail(&entry->skb_list, rx->skb);
entry->last_frag = frag;
entry->extra_len += rx->skb->len;
if (ieee80211_has_morefrags(fc)) {
rx->skb = NULL;
return RX_QUEUED;
}
rx->skb = __skb_dequeue(&entry->skb_list);
if (skb_tailroom(rx->skb) < entry->extra_len) {
I802_DEBUG_INC(rx->local->rx_expand_skb_head2);
if (unlikely(pskb_expand_head(rx->skb, 0, entry->extra_len,
GFP_ATOMIC))) {
I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
__skb_queue_purge(&entry->skb_list);
return RX_DROP_UNUSABLE;
}
}
while ((skb = __skb_dequeue(&entry->skb_list))) {
memcpy(skb_put(rx->skb, skb->len), skb->data, skb->len);
dev_kfree_skb(skb);
}
/* Complete frame has been reassembled - process it now */
rx->flags |= IEEE80211_RX_FRAGMENTED;
out:
if (rx->sta)
rx->sta->rx_packets++;
if (is_multicast_ether_addr(hdr->addr1))
rx->local->dot11MulticastReceivedFrameCount++;
else
ieee80211_led_rx(rx->local);
return RX_CONTINUE;
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_ps_poll(struct ieee80211_rx_data *rx)
{
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
struct ieee80211_sub_if_data *sdata = rx->sdata;
__le16 fc = ((struct ieee80211_hdr *)rx->skb->data)->frame_control;
if (likely(!rx->sta || !ieee80211_is_pspoll(fc) ||
!(rx->flags & IEEE80211_RX_RA_MATCH)))
return RX_CONTINUE;
if ((sdata->vif.type != NL80211_IFTYPE_AP) &&
(sdata->vif.type != NL80211_IFTYPE_AP_VLAN))
return RX_DROP_UNUSABLE;
mac80211: async station powersave handling Some devices require that all frames to a station are flushed when that station goes into powersave mode before being able to send frames to that station again when it wakes up or polls -- all in order to avoid reordering and too many or too few frames being sent to the station when it polls. Normally, this is the case unless the station goes to sleep and wakes up very quickly again. But in that case, frames for it may be pending on the hardware queues, and thus races could happen in the case of multiple hardware queues used for QoS/WMM. Normally this isn't a problem, but with the iwlwifi mechanism we need to make sure the race doesn't happen. This makes mac80211 able to cope with the race with driver help by a new WLAN_STA_PS_DRIVER per-station flag that can be controlled by the driver and tells mac80211 whether it can transmit frames or not. This flag must be set according to very specific rules outlined in the documentation for the function that controls it. When we buffer new frames for the station, we normally set the TIM bit right away, but while the driver has blocked transmission to that sta we need to avoid that as well since we cannot respond to the station if it wakes up due to the TIM bit. Once the driver unblocks, we can set the TIM bit. Similarly, when the station just wakes up, we need to wait until all other frames are flushed before we can transmit frames to that station, so the same applies here, we need to wait for the driver to give the OK. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-06 11:35:50 +01:00
if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
ieee80211_sta_ps_deliver_poll_response(rx->sta);
else
set_sta_flags(rx->sta, WLAN_STA_PSPOLL);
/* Free PS Poll skb here instead of returning RX_DROP that would
* count as an dropped frame. */
dev_kfree_skb(rx->skb);
return RX_QUEUED;
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_remove_qos_control(struct ieee80211_rx_data *rx)
{
u8 *data = rx->skb->data;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)data;
if (!ieee80211_is_data_qos(hdr->frame_control))
return RX_CONTINUE;
/* remove the qos control field, update frame type and meta-data */
memmove(data + IEEE80211_QOS_CTL_LEN, data,
ieee80211_hdrlen(hdr->frame_control) - IEEE80211_QOS_CTL_LEN);
hdr = (struct ieee80211_hdr *)skb_pull(rx->skb, IEEE80211_QOS_CTL_LEN);
/* change frame type to non QOS */
hdr->frame_control &= ~cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
return RX_CONTINUE;
}
static int
ieee80211_802_1x_port_control(struct ieee80211_rx_data *rx)
{
if (unlikely(!rx->sta ||
!test_sta_flags(rx->sta, WLAN_STA_AUTHORIZED)))
return -EACCES;
return 0;
}
static int
ieee80211_drop_unencrypted(struct ieee80211_rx_data *rx, __le16 fc)
{
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
/*
* Pass through unencrypted frames if the hardware has
* decrypted them already.
*/
if (status->flag & RX_FLAG_DECRYPTED)
return 0;
/* Drop unencrypted frames if key is set. */
if (unlikely(!ieee80211_has_protected(fc) &&
!ieee80211_is_nullfunc(fc) &&
ieee80211_is_data(fc) &&
(rx->key || rx->sdata->drop_unencrypted)))
return -EACCES;
return 0;
}
static int
ieee80211_drop_unencrypted_mgmt(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
__le16 fc = hdr->frame_control;
/*
* Pass through unencrypted frames if the hardware has
* decrypted them already.
*/
if (status->flag & RX_FLAG_DECRYPTED)
return 0;
if (rx->sta && test_sta_flags(rx->sta, WLAN_STA_MFP)) {
if (unlikely(!ieee80211_has_protected(fc) &&
ieee80211_is_unicast_robust_mgmt_frame(rx->skb) &&
rx->key))
return -EACCES;
/* BIP does not use Protected field, so need to check MMIE */
if (unlikely(ieee80211_is_multicast_robust_mgmt_frame(rx->skb) &&
ieee80211_get_mmie_keyidx(rx->skb) < 0))
return -EACCES;
/*
* When using MFP, Action frames are not allowed prior to
* having configured keys.
*/
if (unlikely(ieee80211_is_action(fc) && !rx->key &&
ieee80211_is_robust_mgmt_frame(
(struct ieee80211_hdr *) rx->skb->data)))
return -EACCES;
}
return 0;
}
static int
__ieee80211_data_to_8023(struct ieee80211_rx_data *rx)
{
struct ieee80211_sub_if_data *sdata = rx->sdata;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
if (ieee80211_has_a4(hdr->frame_control) &&
sdata->vif.type == NL80211_IFTYPE_AP_VLAN && !sdata->u.vlan.sta)
return -1;
if (is_multicast_ether_addr(hdr->addr1) &&
((sdata->vif.type == NL80211_IFTYPE_AP_VLAN && sdata->u.vlan.sta) ||
(sdata->vif.type == NL80211_IFTYPE_STATION && sdata->u.mgd.use_4addr)))
return -1;
return ieee80211_data_to_8023(rx->skb, sdata->vif.addr, sdata->vif.type);
}
/*
* requires that rx->skb is a frame with ethernet header
*/
static bool ieee80211_frame_allowed(struct ieee80211_rx_data *rx, __le16 fc)
{
static const u8 pae_group_addr[ETH_ALEN] __aligned(2)
= { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x03 };
struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
/*
* Allow EAPOL frames to us/the PAE group address regardless
* of whether the frame was encrypted or not.
*/
if (ehdr->h_proto == htons(ETH_P_PAE) &&
(compare_ether_addr(ehdr->h_dest, rx->sdata->vif.addr) == 0 ||
compare_ether_addr(ehdr->h_dest, pae_group_addr) == 0))
return true;
if (ieee80211_802_1x_port_control(rx) ||
ieee80211_drop_unencrypted(rx, fc))
return false;
return true;
}
/*
* requires that rx->skb is a frame with ethernet header
*/
static void
ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
{
struct ieee80211_sub_if_data *sdata = rx->sdata;
struct net_device *dev = sdata->dev;
struct sk_buff *skb, *xmit_skb;
struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
struct sta_info *dsta;
skb = rx->skb;
xmit_skb = NULL;
if ((sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
!(sdata->flags & IEEE80211_SDATA_DONT_BRIDGE_PACKETS) &&
(rx->flags & IEEE80211_RX_RA_MATCH) &&
(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->u.vlan.sta)) {
if (is_multicast_ether_addr(ehdr->h_dest)) {
/*
* send multicast frames both to higher layers in
* local net stack and back to the wireless medium
*/
xmit_skb = skb_copy(skb, GFP_ATOMIC);
if (!xmit_skb && net_ratelimit())
printk(KERN_DEBUG "%s: failed to clone "
"multicast frame\n", dev->name);
} else {
dsta = sta_info_get(sdata, skb->data);
if (dsta) {
/*
* The destination station is associated to
* this AP (in this VLAN), so send the frame
* directly to it and do not pass it to local
* net stack.
*/
xmit_skb = skb;
skb = NULL;
}
}
}
if (skb) {
int align __maybe_unused;
#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
/*
* 'align' will only take the values 0 or 2 here
* since all frames are required to be aligned
* to 2-byte boundaries when being passed to
* mac80211. That also explains the __skb_push()
* below.
*/
align = ((unsigned long)(skb->data + sizeof(struct ethhdr))) & 3;
if (align) {
if (WARN_ON(skb_headroom(skb) < 3)) {
dev_kfree_skb(skb);
skb = NULL;
} else {
u8 *data = skb->data;
size_t len = skb_headlen(skb);
skb->data -= align;
memmove(skb->data, data, len);
skb_set_tail_pointer(skb, len);
}
}
#endif
if (skb) {
/* deliver to local stack */
skb->protocol = eth_type_trans(skb, dev);
memset(skb->cb, 0, sizeof(skb->cb));
netif_receive_skb(skb);
}
}
if (xmit_skb) {
/* send to wireless media */
xmit_skb->protocol = htons(ETH_P_802_3);
skb_reset_network_header(xmit_skb);
skb_reset_mac_header(xmit_skb);
dev_queue_xmit(xmit_skb);
}
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
{
struct net_device *dev = rx->sdata->dev;
struct sk_buff *skb = rx->skb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
__le16 fc = hdr->frame_control;
struct sk_buff_head frame_list;
if (unlikely(!ieee80211_is_data(fc)))
return RX_CONTINUE;
if (unlikely(!ieee80211_is_data_present(fc)))
return RX_DROP_MONITOR;
if (!(rx->flags & IEEE80211_RX_AMSDU))
return RX_CONTINUE;
if (ieee80211_has_a4(hdr->frame_control) &&
rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
!rx->sdata->u.vlan.sta)
return RX_DROP_UNUSABLE;
if (is_multicast_ether_addr(hdr->addr1) &&
((rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
rx->sdata->u.vlan.sta) ||
(rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
rx->sdata->u.mgd.use_4addr)))
return RX_DROP_UNUSABLE;
skb->dev = dev;
__skb_queue_head_init(&frame_list);
if (skb_linearize(skb))
return RX_DROP_UNUSABLE;
ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
rx->sdata->vif.type,
rx->local->hw.extra_tx_headroom);
while (!skb_queue_empty(&frame_list)) {
rx->skb = __skb_dequeue(&frame_list);
if (!ieee80211_frame_allowed(rx, fc)) {
dev_kfree_skb(rx->skb);
continue;
}
dev->stats.rx_packets++;
dev->stats.rx_bytes += rx->skb->len;
ieee80211_deliver_skb(rx);
}
return RX_QUEUED;
}
#ifdef CONFIG_MAC80211_MESH
static ieee80211_rx_result
ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr;
struct ieee80211s_hdr *mesh_hdr;
unsigned int hdrlen;
struct sk_buff *skb = rx->skb, *fwd_skb;
struct ieee80211_local *local = rx->local;
struct ieee80211_sub_if_data *sdata = rx->sdata;
hdr = (struct ieee80211_hdr *) skb->data;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
if (!ieee80211_is_data(hdr->frame_control))
return RX_CONTINUE;
if (!mesh_hdr->ttl)
/* illegal frame */
return RX_DROP_MONITOR;
if (mesh_hdr->flags & MESH_FLAGS_AE) {
struct mesh_path *mppath;
char *proxied_addr;
char *mpp_addr;
if (is_multicast_ether_addr(hdr->addr1)) {
mpp_addr = hdr->addr3;
proxied_addr = mesh_hdr->eaddr1;
} else {
mpp_addr = hdr->addr4;
proxied_addr = mesh_hdr->eaddr2;
}
rcu_read_lock();
mppath = mpp_path_lookup(proxied_addr, sdata);
if (!mppath) {
mpp_path_add(proxied_addr, mpp_addr, sdata);
} else {
spin_lock_bh(&mppath->state_lock);
if (compare_ether_addr(mppath->mpp, mpp_addr) != 0)
memcpy(mppath->mpp, mpp_addr, ETH_ALEN);
spin_unlock_bh(&mppath->state_lock);
}
rcu_read_unlock();
}
/* Frame has reached destination. Don't forward */
if (!is_multicast_ether_addr(hdr->addr1) &&
compare_ether_addr(sdata->vif.addr, hdr->addr3) == 0)
return RX_CONTINUE;
mesh_hdr->ttl--;
if (rx->flags & IEEE80211_RX_RA_MATCH) {
if (!mesh_hdr->ttl)
IEEE80211_IFSTA_MESH_CTR_INC(&rx->sdata->u.mesh,
dropped_frames_ttl);
else {
struct ieee80211_hdr *fwd_hdr;
struct ieee80211_tx_info *info;
fwd_skb = skb_copy(skb, GFP_ATOMIC);
if (!fwd_skb && net_ratelimit())
printk(KERN_DEBUG "%s: failed to clone mesh frame\n",
sdata->name);
fwd_hdr = (struct ieee80211_hdr *) fwd_skb->data;
memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
info = IEEE80211_SKB_CB(fwd_skb);
memset(info, 0, sizeof(*info));
info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
info->control.vif = &rx->sdata->vif;
skb_set_queue_mapping(skb,
ieee80211_select_queue(rx->sdata, fwd_skb));
ieee80211_set_qos_hdr(local, skb);
if (is_multicast_ether_addr(fwd_hdr->addr1))
IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
fwded_mcast);
else {
int err;
/*
* Save TA to addr1 to send TA a path error if a
* suitable next hop is not found
*/
memcpy(fwd_hdr->addr1, fwd_hdr->addr2,
ETH_ALEN);
err = mesh_nexthop_lookup(fwd_skb, sdata);
/* Failed to immediately resolve next hop:
* fwded frame was dropped or will be added
* later to the pending skb queue. */
if (err)
return RX_DROP_MONITOR;
IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
fwded_unicast);
}
IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
fwded_frames);
ieee80211_add_pending_skb(local, fwd_skb);
}
}
if (is_multicast_ether_addr(hdr->addr1) ||
sdata->dev->flags & IFF_PROMISC)
return RX_CONTINUE;
else
return RX_DROP_MONITOR;
}
#endif
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
{
struct ieee80211_sub_if_data *sdata = rx->sdata;
struct ieee80211_local *local = rx->local;
struct net_device *dev = sdata->dev;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
__le16 fc = hdr->frame_control;
int err;
if (unlikely(!ieee80211_is_data(hdr->frame_control)))
return RX_CONTINUE;
if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
return RX_DROP_MONITOR;
/*
* Allow the cooked monitor interface of an AP to see 4-addr frames so
* that a 4-addr station can be detected and moved into a separate VLAN
*/
if (ieee80211_has_a4(hdr->frame_control) &&
sdata->vif.type == NL80211_IFTYPE_AP)
return RX_DROP_MONITOR;
err = __ieee80211_data_to_8023(rx);
if (unlikely(err))
return RX_DROP_UNUSABLE;
if (!ieee80211_frame_allowed(rx, fc))
return RX_DROP_MONITOR;
rx->skb->dev = dev;
dev->stats.rx_packets++;
dev->stats.rx_bytes += rx->skb->len;
if (ieee80211_is_data(hdr->frame_control) &&
!is_multicast_ether_addr(hdr->addr1) &&
local->hw.conf.dynamic_ps_timeout > 0 && local->ps_sdata) {
mod_timer(&local->dynamic_ps_timer, jiffies +
msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
}
ieee80211_deliver_skb(rx);
return RX_QUEUED;
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx, struct sk_buff_head *frames)
{
struct ieee80211_local *local = rx->local;
struct ieee80211_hw *hw = &local->hw;
struct sk_buff *skb = rx->skb;
struct ieee80211_bar *bar = (struct ieee80211_bar *)skb->data;
struct tid_ampdu_rx *tid_agg_rx;
u16 start_seq_num;
u16 tid;
if (likely(!ieee80211_is_ctl(bar->frame_control)))
return RX_CONTINUE;
if (ieee80211_is_back_req(bar->frame_control)) {
struct {
__le16 control, start_seq_num;
} __packed bar_data;
if (!rx->sta)
return RX_DROP_MONITOR;
if (skb_copy_bits(skb, offsetof(struct ieee80211_bar, control),
&bar_data, sizeof(bar_data)))
return RX_DROP_MONITOR;
tid = le16_to_cpu(bar_data.control) >> 12;
tid_agg_rx = rcu_dereference(rx->sta->ampdu_mlme.tid_rx[tid]);
if (!tid_agg_rx)
return RX_DROP_MONITOR;
start_seq_num = le16_to_cpu(bar_data.start_seq_num) >> 4;
/* reset session timer */
if (tid_agg_rx->timeout)
mod_timer(&tid_agg_rx->session_timer,
TU_TO_EXP_TIME(tid_agg_rx->timeout));
/* release stored frames up to start of BAR */
ieee80211_release_reorder_frames(hw, tid_agg_rx, start_seq_num,
frames);
kfree_skb(skb);
return RX_QUEUED;
}
/*
* After this point, we only want management frames,
* so we can drop all remaining control frames to
* cooked monitor interfaces.
*/
return RX_DROP_MONITOR;
}
static void ieee80211_process_sa_query_req(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
size_t len)
{
struct ieee80211_local *local = sdata->local;
struct sk_buff *skb;
struct ieee80211_mgmt *resp;
if (compare_ether_addr(mgmt->da, sdata->vif.addr) != 0) {
/* Not to own unicast address */
return;
}
if (compare_ether_addr(mgmt->sa, sdata->u.mgd.bssid) != 0 ||
compare_ether_addr(mgmt->bssid, sdata->u.mgd.bssid) != 0) {
/* Not from the current AP or not associated yet. */
return;
}
if (len < 24 + 1 + sizeof(resp->u.action.u.sa_query)) {
/* Too short SA Query request frame */
return;
}
skb = dev_alloc_skb(sizeof(*resp) + local->hw.extra_tx_headroom);
if (skb == NULL)
return;
skb_reserve(skb, local->hw.extra_tx_headroom);
resp = (struct ieee80211_mgmt *) skb_put(skb, 24);
memset(resp, 0, 24);
memcpy(resp->da, mgmt->sa, ETH_ALEN);
memcpy(resp->sa, sdata->vif.addr, ETH_ALEN);
memcpy(resp->bssid, sdata->u.mgd.bssid, ETH_ALEN);
resp->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_ACTION);
skb_put(skb, 1 + sizeof(resp->u.action.u.sa_query));
resp->u.action.category = WLAN_CATEGORY_SA_QUERY;
resp->u.action.u.sa_query.action = WLAN_ACTION_SA_QUERY_RESPONSE;
memcpy(resp->u.action.u.sa_query.trans_id,
mgmt->u.action.u.sa_query.trans_id,
WLAN_SA_QUERY_TR_ID_LEN);
ieee80211_tx_skb(sdata, skb);
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
{
struct ieee80211_local *local = rx->local;
struct ieee80211_sub_if_data *sdata = rx->sdata;
struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
struct sk_buff *nskb;
struct ieee80211_rx_status *status;
int len = rx->skb->len;
if (!ieee80211_is_action(mgmt->frame_control))
return RX_CONTINUE;
/* drop too small frames */
if (len < IEEE80211_MIN_ACTION_SIZE)
return RX_DROP_UNUSABLE;
if (!rx->sta && mgmt->u.action.category != WLAN_CATEGORY_PUBLIC)
return RX_DROP_UNUSABLE;
if (!(rx->flags & IEEE80211_RX_RA_MATCH))
return RX_DROP_UNUSABLE;
if (ieee80211_drop_unencrypted_mgmt(rx))
return RX_DROP_UNUSABLE;
switch (mgmt->u.action.category) {
case WLAN_CATEGORY_BACK:
/*
* The aggregation code is not prepared to handle
* anything but STA/AP due to the BSSID handling;
* IBSS could work in the code but isn't supported
* by drivers or the standard.
*/
if (sdata->vif.type != NL80211_IFTYPE_STATION &&
sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
sdata->vif.type != NL80211_IFTYPE_AP)
break;
/* verify action_code is present */
if (len < IEEE80211_MIN_ACTION_SIZE + 1)
break;
switch (mgmt->u.action.u.addba_req.action_code) {
case WLAN_ACTION_ADDBA_REQ:
if (len < (IEEE80211_MIN_ACTION_SIZE +
sizeof(mgmt->u.action.u.addba_req)))
goto invalid;
break;
case WLAN_ACTION_ADDBA_RESP:
if (len < (IEEE80211_MIN_ACTION_SIZE +
sizeof(mgmt->u.action.u.addba_resp)))
goto invalid;
break;
case WLAN_ACTION_DELBA:
if (len < (IEEE80211_MIN_ACTION_SIZE +
sizeof(mgmt->u.action.u.delba)))
goto invalid;
break;
default:
goto invalid;
}
goto queue;
case WLAN_CATEGORY_SPECTRUM_MGMT:
if (local->hw.conf.channel->band != IEEE80211_BAND_5GHZ)
break;
if (sdata->vif.type != NL80211_IFTYPE_STATION)
break;
/* verify action_code is present */
if (len < IEEE80211_MIN_ACTION_SIZE + 1)
break;
switch (mgmt->u.action.u.measurement.action_code) {
case WLAN_ACTION_SPCT_MSR_REQ:
if (len < (IEEE80211_MIN_ACTION_SIZE +
sizeof(mgmt->u.action.u.measurement)))
break;
ieee80211_process_measurement_req(sdata, mgmt, len);
goto handled;
case WLAN_ACTION_SPCT_CHL_SWITCH:
if (len < (IEEE80211_MIN_ACTION_SIZE +
sizeof(mgmt->u.action.u.chan_switch)))
break;
if (sdata->vif.type != NL80211_IFTYPE_STATION)
break;
if (memcmp(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN))
break;
goto queue;
}
break;
case WLAN_CATEGORY_SA_QUERY:
if (len < (IEEE80211_MIN_ACTION_SIZE +
sizeof(mgmt->u.action.u.sa_query)))
break;
switch (mgmt->u.action.u.sa_query.action) {
case WLAN_ACTION_SA_QUERY_REQUEST:
if (sdata->vif.type != NL80211_IFTYPE_STATION)
break;
ieee80211_process_sa_query_req(sdata, mgmt, len);
goto handled;
}
break;
case WLAN_CATEGORY_MESH_PLINK:
case WLAN_CATEGORY_MESH_PATH_SEL:
if (!ieee80211_vif_is_mesh(&sdata->vif))
break;
goto queue;
}
invalid:
/*
* For AP mode, hostapd is responsible for handling any action
* frames that we didn't handle, including returning unknown
* ones. For all other modes we will return them to the sender,
* setting the 0x80 bit in the action category, as required by
* 802.11-2007 7.3.1.11.
*/
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
return RX_DROP_MONITOR;
/*
* Getting here means the kernel doesn't know how to handle
* it, but maybe userspace does ... include returned frames
* so userspace can register for those to know whether ones
* it transmitted were processed or returned.
*/
status = IEEE80211_SKB_RXCB(rx->skb);
if (cfg80211_rx_action(rx->sdata->dev, status->freq,
rx->skb->data, rx->skb->len,
GFP_ATOMIC))
goto handled;
/* do not return rejected action frames */
if (mgmt->u.action.category & 0x80)
return RX_DROP_UNUSABLE;
nskb = skb_copy_expand(rx->skb, local->hw.extra_tx_headroom, 0,
GFP_ATOMIC);
if (nskb) {
struct ieee80211_mgmt *nmgmt = (void *)nskb->data;
nmgmt->u.action.category |= 0x80;
memcpy(nmgmt->da, nmgmt->sa, ETH_ALEN);
memcpy(nmgmt->sa, rx->sdata->vif.addr, ETH_ALEN);
memset(nskb->cb, 0, sizeof(nskb->cb));
ieee80211_tx_skb(rx->sdata, nskb);
}
handled:
if (rx->sta)
rx->sta->rx_packets++;
dev_kfree_skb(rx->skb);
return RX_QUEUED;
queue:
rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
skb_queue_tail(&sdata->skb_queue, rx->skb);
ieee80211_queue_work(&local->hw, &sdata->work);
if (rx->sta)
rx->sta->rx_packets++;
return RX_QUEUED;
}
static ieee80211_rx_result debug_noinline
ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
{
struct ieee80211_sub_if_data *sdata = rx->sdata;
ieee80211_rx_result rxs;
struct ieee80211_mgmt *mgmt = (void *)rx->skb->data;
__le16 stype;
if (!(rx->flags & IEEE80211_RX_RA_MATCH))
return RX_DROP_MONITOR;
if (rx->skb->len < 24)
return RX_DROP_MONITOR;
if (ieee80211_drop_unencrypted_mgmt(rx))
return RX_DROP_UNUSABLE;
rxs = ieee80211_work_rx_mgmt(rx->sdata, rx->skb);
if (rxs != RX_CONTINUE)
return rxs;
stype = mgmt->frame_control & cpu_to_le16(IEEE80211_FCTL_STYPE);
if (!ieee80211_vif_is_mesh(&sdata->vif) &&
sdata->vif.type != NL80211_IFTYPE_ADHOC &&
sdata->vif.type != NL80211_IFTYPE_STATION)
return RX_DROP_MONITOR;
switch (stype) {
case cpu_to_le16(IEEE80211_STYPE_BEACON):
case cpu_to_le16(IEEE80211_STYPE_PROBE_RESP):
/* process for all: mesh, mlme, ibss */
break;
case cpu_to_le16(IEEE80211_STYPE_DEAUTH):
case cpu_to_le16(IEEE80211_STYPE_DISASSOC):
/* process only for station */
if (sdata->vif.type != NL80211_IFTYPE_STATION)
return RX_DROP_MONITOR;
break;
case cpu_to_le16(IEEE80211_STYPE_PROBE_REQ):
case cpu_to_le16(IEEE80211_STYPE_AUTH):
/* process only for ibss */
if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
return RX_DROP_MONITOR;
break;
default:
return RX_DROP_MONITOR;
}
/* queue up frame and kick off work to process it */
rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
skb_queue_tail(&sdata->skb_queue, rx->skb);
ieee80211_queue_work(&rx->local->hw, &sdata->work);
if (rx->sta)
rx->sta->rx_packets++;
return RX_QUEUED;
}
static void ieee80211_rx_michael_mic_report(struct ieee80211_hdr *hdr,
struct ieee80211_rx_data *rx)
{
int keyidx;
unsigned int hdrlen;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (rx->skb->len >= hdrlen + 4)
keyidx = rx->skb->data[hdrlen + 3] >> 6;
else
keyidx = -1;
if (!rx->sta) {
/*
* Some hardware seem to generate incorrect Michael MIC
* reports; ignore them to avoid triggering countermeasures.
*/
return;
}
if (!ieee80211_has_protected(hdr->frame_control))
return;
if (rx->sdata->vif.type == NL80211_IFTYPE_AP && keyidx) {
/*
* APs with pairwise keys should never receive Michael MIC
* errors for non-zero keyidx because these are reserved for
* group keys and only the AP is sending real multicast
* frames in the BSS.
*/
return;
}
if (!ieee80211_is_data(hdr->frame_control) &&
!ieee80211_is_auth(hdr->frame_control))
return;
mac80211_ev_michael_mic_failure(rx->sdata, keyidx, hdr, NULL,
GFP_ATOMIC);
}
/* TODO: use IEEE80211_RX_FRAGMENTED */
static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx,
struct ieee80211_rate *rate)
{
struct ieee80211_sub_if_data *sdata;
struct ieee80211_local *local = rx->local;
struct ieee80211_rtap_hdr {
struct ieee80211_radiotap_header hdr;
u8 flags;
u8 rate_or_pad;
__le16 chan_freq;
__le16 chan_flags;
} __packed *rthdr;
struct sk_buff *skb = rx->skb, *skb2;
struct net_device *prev_dev = NULL;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
if (status->flag & RX_FLAG_INTERNAL_CMTR)
goto out_free_skb;
if (skb_headroom(skb) < sizeof(*rthdr) &&
pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC))
goto out_free_skb;
rthdr = (void *)skb_push(skb, sizeof(*rthdr));
memset(rthdr, 0, sizeof(*rthdr));
rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
rthdr->hdr.it_present =
cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
(1 << IEEE80211_RADIOTAP_CHANNEL));
if (rate) {
rthdr->rate_or_pad = rate->bitrate / 5;
rthdr->hdr.it_present |=
cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
}
rthdr->chan_freq = cpu_to_le16(status->freq);
if (status->band == IEEE80211_BAND_5GHZ)
rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_OFDM |
IEEE80211_CHAN_5GHZ);
else
rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_DYN |
IEEE80211_CHAN_2GHZ);
skb_set_mac_header(skb, 0);
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->pkt_type = PACKET_OTHERHOST;
skb->protocol = htons(ETH_P_802_2);
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
continue;
if (sdata->vif.type != NL80211_IFTYPE_MONITOR ||
!(sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES))
continue;
if (prev_dev) {
skb2 = skb_clone(skb, GFP_ATOMIC);
if (skb2) {
skb2->dev = prev_dev;
netif_receive_skb(skb2);
}
}
prev_dev = sdata->dev;
sdata->dev->stats.rx_packets++;
sdata->dev->stats.rx_bytes += skb->len;
}
if (prev_dev) {
skb->dev = prev_dev;
netif_receive_skb(skb);
skb = NULL;
} else
goto out_free_skb;
status->flag |= RX_FLAG_INTERNAL_CMTR;
return;
out_free_skb:
dev_kfree_skb(skb);
}
static void ieee80211_invoke_rx_handlers(struct ieee80211_sub_if_data *sdata,
struct ieee80211_rx_data *rx,
struct sk_buff *skb,
struct ieee80211_rate *rate)
{
struct sk_buff_head reorder_release;
ieee80211_rx_result res = RX_DROP_MONITOR;
__skb_queue_head_init(&reorder_release);
rx->skb = skb;
rx->sdata = sdata;
#define CALL_RXH(rxh) \
do { \
res = rxh(rx); \
if (res != RX_CONTINUE) \
goto rxh_next; \
} while (0);
/*
* NB: the rxh_next label works even if we jump
* to it from here because then the list will
* be empty, which is a trivial check
*/
CALL_RXH(ieee80211_rx_h_passive_scan)
CALL_RXH(ieee80211_rx_h_check)
ieee80211_rx_reorder_ampdu(rx, &reorder_release);
while ((skb = __skb_dequeue(&reorder_release))) {
/*
* all the other fields are valid across frames
* that belong to an aMPDU since they are on the
* same TID from the same station
*/
rx->skb = skb;
CALL_RXH(ieee80211_rx_h_decrypt)
CALL_RXH(ieee80211_rx_h_check_more_data)
CALL_RXH(ieee80211_rx_h_sta_process)
CALL_RXH(ieee80211_rx_h_defragment)
CALL_RXH(ieee80211_rx_h_ps_poll)
CALL_RXH(ieee80211_rx_h_michael_mic_verify)
/* must be after MMIC verify so header is counted in MPDU mic */
CALL_RXH(ieee80211_rx_h_remove_qos_control)
CALL_RXH(ieee80211_rx_h_amsdu)
#ifdef CONFIG_MAC80211_MESH
if (ieee80211_vif_is_mesh(&sdata->vif))
CALL_RXH(ieee80211_rx_h_mesh_fwding);
#endif
CALL_RXH(ieee80211_rx_h_data)
/* special treatment -- needs the queue */
res = ieee80211_rx_h_ctrl(rx, &reorder_release);
if (res != RX_CONTINUE)
goto rxh_next;
CALL_RXH(ieee80211_rx_h_action)
CALL_RXH(ieee80211_rx_h_mgmt)
#undef CALL_RXH
rxh_next:
switch (res) {
case RX_DROP_MONITOR:
I802_DEBUG_INC(sdata->local->rx_handlers_drop);
if (rx->sta)
rx->sta->rx_dropped++;
/* fall through */
case RX_CONTINUE:
ieee80211_rx_cooked_monitor(rx, rate);
break;
case RX_DROP_UNUSABLE:
I802_DEBUG_INC(sdata->local->rx_handlers_drop);
if (rx->sta)
rx->sta->rx_dropped++;
dev_kfree_skb(rx->skb);
break;
case RX_QUEUED:
I802_DEBUG_INC(sdata->local->rx_handlers_queued);
break;
}
}
}
/* main receive path */
static int prepare_for_handlers(struct ieee80211_sub_if_data *sdata,
struct ieee80211_rx_data *rx,
struct ieee80211_hdr *hdr)
{
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
u8 *bssid = ieee80211_get_bssid(hdr, skb->len, sdata->vif.type);
int multicast = is_multicast_ether_addr(hdr->addr1);
switch (sdata->vif.type) {
case NL80211_IFTYPE_STATION:
if (!bssid && !sdata->u.mgd.use_4addr)
return 0;
if (!multicast &&
compare_ether_addr(sdata->vif.addr, hdr->addr1) != 0) {
[PATCH] mac80211: revamp interface and filter configuration Drivers are currently supposed to keep track of monitor interfaces if they allow so-called "hard" monitor, and they are also supposed to keep track of multicast etc. This patch changes that, replaces the set_multicast_list() callback with a new configure_filter() callback that takes filter flags (FIF_*) instead of interface flags (IFF_*). For a driver, this means it should open the filter as much as necessary to get all frames requested by the filter flags. Accordingly, the filter flags are named "positively", e.g. FIF_ALLMULTI. Multicast filtering is a bit special in that drivers that have no multicast address filters need to allow multicast frames through when either the FIF_ALLMULTI flag is set or when the mc_count value is positive. At the same time, drivers are no longer notified about monitor interfaces at all, this means they now need to implement the start() and stop() callbacks and the new change_filter_flags() callback. Also, the start()/stop() ordering changed, start() is now called *before* any add_interface() as it really should be, and stop() after any remove_interface(). The patch also changes the behaviour of setting the bssid to multicast for scanning when IEEE80211_HW_NO_PROBE_FILTERING is set; the IEEE80211_HW_NO_PROBE_FILTERING flag is removed and the filter flag FIF_BCN_PRBRESP_PROMISC introduced. This is a lot more efficient for hardware like b43 that supports it and other hardware can still set the BSSID to all-ones. Driver modifications by Johannes Berg (b43 & iwlwifi), Michael Wu (rtl8187, adm8211, and p54), Larry Finger (b43legacy), and Ivo van Doorn (rt2x00). Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Michael Wu <flamingice@sourmilk.net> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2007-09-17 07:29:23 +02:00
if (!(sdata->dev->flags & IFF_PROMISC))
return 0;
rx->flags &= ~IEEE80211_RX_RA_MATCH;
}
break;
case NL80211_IFTYPE_ADHOC:
if (!bssid)
return 0;
if (ieee80211_is_beacon(hdr->frame_control)) {
return 1;
}
else if (!ieee80211_bssid_match(bssid, sdata->u.ibss.bssid)) {
if (!(rx->flags & IEEE80211_RX_IN_SCAN))
return 0;
rx->flags &= ~IEEE80211_RX_RA_MATCH;
} else if (!multicast &&
compare_ether_addr(sdata->vif.addr,
hdr->addr1) != 0) {
[PATCH] mac80211: revamp interface and filter configuration Drivers are currently supposed to keep track of monitor interfaces if they allow so-called "hard" monitor, and they are also supposed to keep track of multicast etc. This patch changes that, replaces the set_multicast_list() callback with a new configure_filter() callback that takes filter flags (FIF_*) instead of interface flags (IFF_*). For a driver, this means it should open the filter as much as necessary to get all frames requested by the filter flags. Accordingly, the filter flags are named "positively", e.g. FIF_ALLMULTI. Multicast filtering is a bit special in that drivers that have no multicast address filters need to allow multicast frames through when either the FIF_ALLMULTI flag is set or when the mc_count value is positive. At the same time, drivers are no longer notified about monitor interfaces at all, this means they now need to implement the start() and stop() callbacks and the new change_filter_flags() callback. Also, the start()/stop() ordering changed, start() is now called *before* any add_interface() as it really should be, and stop() after any remove_interface(). The patch also changes the behaviour of setting the bssid to multicast for scanning when IEEE80211_HW_NO_PROBE_FILTERING is set; the IEEE80211_HW_NO_PROBE_FILTERING flag is removed and the filter flag FIF_BCN_PRBRESP_PROMISC introduced. This is a lot more efficient for hardware like b43 that supports it and other hardware can still set the BSSID to all-ones. Driver modifications by Johannes Berg (b43 & iwlwifi), Michael Wu (rtl8187, adm8211, and p54), Larry Finger (b43legacy), and Ivo van Doorn (rt2x00). Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Michael Wu <flamingice@sourmilk.net> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
2007-09-17 07:29:23 +02:00
if (!(sdata->dev->flags & IFF_PROMISC))
return 0;
rx->flags &= ~IEEE80211_RX_RA_MATCH;
} else if (!rx->sta) {
int rate_idx;
if (status->flag & RX_FLAG_HT)
rate_idx = 0; /* TODO: HT rates */
else
rate_idx = status->rate_idx;
rx->sta = ieee80211_ibss_add_sta(sdata, bssid,
hdr->addr2, BIT(rate_idx), GFP_ATOMIC);
}
break;
case NL80211_IFTYPE_MESH_POINT:
if (!multicast &&
compare_ether_addr(sdata->vif.addr,
hdr->addr1) != 0) {
if (!(sdata->dev->flags & IFF_PROMISC))
return 0;
rx->flags &= ~IEEE80211_RX_RA_MATCH;
}
break;
case NL80211_IFTYPE_AP_VLAN:
case NL80211_IFTYPE_AP:
if (!bssid) {
if (compare_ether_addr(sdata->vif.addr,
hdr->addr1))
return 0;
} else if (!ieee80211_bssid_match(bssid,
sdata->vif.addr)) {
if (!(rx->flags & IEEE80211_RX_IN_SCAN))
return 0;
rx->flags &= ~IEEE80211_RX_RA_MATCH;
}
break;
case NL80211_IFTYPE_WDS:
if (bssid || !ieee80211_is_data(hdr->frame_control))
return 0;
if (compare_ether_addr(sdata->u.wds.remote_addr, hdr->addr2))
return 0;
break;
case NL80211_IFTYPE_MONITOR:
case NL80211_IFTYPE_UNSPECIFIED:
case __NL80211_IFTYPE_AFTER_LAST:
/* should never get here */
WARN_ON(1);
break;
}
return 1;
}
/*
* This is the actual Rx frames handler. as it blongs to Rx path it must
* be called with rcu_read_lock protection.
*/
static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
struct sk_buff *skb,
struct ieee80211_rate *rate)
{
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
struct ieee80211_hdr *hdr;
__le16 fc;
struct ieee80211_rx_data rx;
int prepares;
struct ieee80211_sub_if_data *prev = NULL;
struct sk_buff *skb_new;
struct sta_info *sta, *tmp;
bool found_sta = false;
int err = 0;
fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
memset(&rx, 0, sizeof(rx));
rx.skb = skb;
rx.local = local;
if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))
local->dot11ReceivedFragmentCount++;
if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
test_bit(SCAN_OFF_CHANNEL, &local->scanning)))
rx.flags |= IEEE80211_RX_IN_SCAN;
if (ieee80211_is_mgmt(fc))
err = skb_linearize(skb);
else
err = !pskb_may_pull(skb, ieee80211_hdrlen(fc));
if (err) {
dev_kfree_skb(skb);
return;
}
hdr = (struct ieee80211_hdr *)skb->data;
ieee80211_parse_qos(&rx);
ieee80211_verify_alignment(&rx);
if (ieee80211_is_data(fc)) {
for_each_sta_info(local, hdr->addr2, sta, tmp) {
rx.sta = sta;
found_sta = true;
rx.sdata = sta->sdata;
rx.flags |= IEEE80211_RX_RA_MATCH;
prepares = prepare_for_handlers(rx.sdata, &rx, hdr);
if (prepares) {
if (status->flag & RX_FLAG_MMIC_ERROR) {
if (rx.flags & IEEE80211_RX_RA_MATCH)
ieee80211_rx_michael_mic_report(hdr, &rx);
} else
prev = rx.sdata;
}
}
}
if (!found_sta) {
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
continue;
if (sdata->vif.type == NL80211_IFTYPE_MONITOR ||
sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
continue;
/*
* frame is destined for this interface, but if it's
* not also for the previous one we handle that after
* the loop to avoid copying the SKB once too much
*/
if (!prev) {
prev = sdata;
continue;
}
rx.sta = sta_info_get_bss(prev, hdr->addr2);
rx.flags |= IEEE80211_RX_RA_MATCH;
prepares = prepare_for_handlers(prev, &rx, hdr);
if (!prepares)
goto next;
if (status->flag & RX_FLAG_MMIC_ERROR) {
rx.sdata = prev;
if (rx.flags & IEEE80211_RX_RA_MATCH)
ieee80211_rx_michael_mic_report(hdr,
&rx);
goto next;
}
/*
* frame was destined for the previous interface
* so invoke RX handlers for it
*/
skb_new = skb_copy(skb, GFP_ATOMIC);
if (!skb_new) {
if (net_ratelimit())
printk(KERN_DEBUG "%s: failed to copy "
"multicast frame for %s\n",
wiphy_name(local->hw.wiphy),
prev->name);
goto next;
}
ieee80211_invoke_rx_handlers(prev, &rx, skb_new, rate);
next:
prev = sdata;
}
if (prev) {
rx.sta = sta_info_get_bss(prev, hdr->addr2);
rx.flags |= IEEE80211_RX_RA_MATCH;
prepares = prepare_for_handlers(prev, &rx, hdr);
if (!prepares)
prev = NULL;
}
}
if (prev)
ieee80211_invoke_rx_handlers(prev, &rx, skb, rate);
else
dev_kfree_skb(skb);
}
/*
* This is the receive path handler. It is called by a low level driver when an
* 802.11 MPDU is received from the hardware.
*/
void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_rate *rate = NULL;
struct ieee80211_supported_band *sband;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
WARN_ON_ONCE(softirq_count() == 0);
if (WARN_ON(status->band < 0 ||
status->band >= IEEE80211_NUM_BANDS))
goto drop;
sband = local->hw.wiphy->bands[status->band];
if (WARN_ON(!sband))
goto drop;
/*
* If we're suspending, it is possible although not too likely
* that we'd be receiving frames after having already partially
* quiesced the stack. We can't process such frames then since
* that might, for example, cause stations to be added or other
* driver callbacks be invoked.
*/
if (unlikely(local->quiescing || local->suspended))
goto drop;
/*
* The same happens when we're not even started,
* but that's worth a warning.
*/
if (WARN_ON(!local->started))
goto drop;
if (status->flag & RX_FLAG_HT) {
/*
* rate_idx is MCS index, which can be [0-76] as documented on:
*
* http://wireless.kernel.org/en/developers/Documentation/ieee80211/802.11n
*
* Anything else would be some sort of driver or hardware error.
* The driver should catch hardware errors.
*/
if (WARN((status->rate_idx < 0 ||
status->rate_idx > 76),
"Rate marked as an HT rate but passed "
"status->rate_idx is not "
"an MCS index [0-76]: %d (0x%02x)\n",
status->rate_idx,
status->rate_idx))
goto drop;
} else {
if (WARN_ON(status->rate_idx < 0 ||
status->rate_idx >= sband->n_bitrates))
goto drop;
rate = &sband->bitrates[status->rate_idx];
}
/*
* key references and virtual interfaces are protected using RCU
* and this requires that we are in a read-side RCU section during
* receive processing
*/
rcu_read_lock();
/*
* Frames with failed FCS/PLCP checksum are not returned,
* all other frames are returned without radiotap header
* if it was previously present.
* Also, frames with less than 16 bytes are dropped.
*/
skb = ieee80211_rx_monitor(local, skb, rate);
if (!skb) {
rcu_read_unlock();
return;
}
__ieee80211_rx_handle_packet(hw, skb, rate);
rcu_read_unlock();
return;
drop:
kfree_skb(skb);
}
EXPORT_SYMBOL(ieee80211_rx);
/* This is a version of the rx handler that can be called from hard irq
* context. Post the skb on the queue and schedule the tasklet */
void ieee80211_rx_irqsafe(struct ieee80211_hw *hw, struct sk_buff *skb)
{
struct ieee80211_local *local = hw_to_local(hw);
BUILD_BUG_ON(sizeof(struct ieee80211_rx_status) > sizeof(skb->cb));
skb->pkt_type = IEEE80211_RX_MSG;
skb_queue_tail(&local->skb_queue, skb);
tasklet_schedule(&local->tasklet);
}
EXPORT_SYMBOL(ieee80211_rx_irqsafe);