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rx.c
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/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007-2010 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 <linux/slab.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/rcupdate.h>
#include <linux/export.h>
#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>
#include <asm/unaligned.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"
#include "rate.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)
{
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(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);
return NULL;
}
}
if (status->vendor_radiotap_len)
__pskb_pull(skb, status->vendor_radiotap_len);
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;
hdr = (void *)(skb->data + status->vendor_radiotap_len);
if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
RX_FLAG_FAILED_PLCP_CRC |
RX_FLAG_AMPDU_IS_ZEROLEN))
return 1;
if (unlikely(skb->len < 16 + present_fcs_len +
status->vendor_radiotap_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_space(struct ieee80211_local *local,
struct ieee80211_rx_status *status)
{
int len;
/* always present fields */
len = sizeof(struct ieee80211_radiotap_header) + 9;
/* allocate extra bitmap */
if (status->vendor_radiotap_len)
len += 4;
if (ieee80211_have_rx_timestamp(status)) {
len = ALIGN(len, 8);
len += 8;
}
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
len += 1;
/* padding for RX_FLAGS if necessary */
len = ALIGN(len, 2);
if (status->flag & RX_FLAG_HT) /* HT info */
len += 3;
if (status->flag & RX_FLAG_AMPDU_DETAILS) {
len = ALIGN(len, 4);
len += 8;
}
if (status->flag & RX_FLAG_VHT) {
len = ALIGN(len, 2);
len += 12;
}
if (status->vendor_radiotap_len) {
if (WARN_ON_ONCE(status->vendor_radiotap_align == 0))
status->vendor_radiotap_align = 1;
/* align standard part of vendor namespace */
len = ALIGN(len, 2);
/* allocate standard part of vendor namespace */
len += 6;
/* align vendor-defined part */
len = ALIGN(len, status->vendor_radiotap_align);
/* vendor-defined part is already in skb */
}
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, bool has_fcs)
{
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_radiotap_header *rthdr;
unsigned char *pos;
u16 rx_flags = 0;
int mpdulen;
mpdulen = skb->len;
if (!(has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)))
mpdulen += FCS_LEN;
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 + status->vendor_radiotap_len);
pos = (unsigned char *)(rthdr + 1);
if (status->vendor_radiotap_len) {
rthdr->it_present |=
cpu_to_le32(BIT(IEEE80211_RADIOTAP_VENDOR_NAMESPACE)) |
cpu_to_le32(BIT(IEEE80211_RADIOTAP_EXT));
put_unaligned_le32(status->vendor_radiotap_bitmap, pos);
pos += 4;
}
/* the order of the following fields is important */
/* IEEE80211_RADIOTAP_TSFT */
if (ieee80211_have_rx_timestamp(status)) {
/* padding */
while ((pos - (u8 *)rthdr) & 7)
*pos++ = 0;
put_unaligned_le64(
ieee80211_calculate_rx_timestamp(local, status,
mpdulen, 0),
pos);
rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
pos += 8;
}
/* IEEE80211_RADIOTAP_FLAGS */
if (has_fcs && (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 (!rate || status->flag & (RX_FLAG_HT | RX_FLAG_VHT)) {
/*
* Without rate information don't add it. If we have,
* MCS information is a separate field in radiotap,
* added below. The byte here is needed as padding
* for the channel though, so initialise it to 0.
*/
*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 | RX_FLAG_VHT))
put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
pos);
else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
pos);
else if (rate)
put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
pos);
else
put_unaligned_le16(IEEE80211_CHAN_2GHZ, pos);
pos += 2;
/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM &&
!(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
*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++ = 0;
if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
put_unaligned_le16(rx_flags, pos);
pos += 2;
if (status->flag & RX_FLAG_HT) {
rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
*pos++ = local->hw.radiotap_mcs_details;
*pos = 0;
if (status->flag & RX_FLAG_SHORT_GI)
*pos |= IEEE80211_RADIOTAP_MCS_SGI;
if (status->flag & RX_FLAG_40MHZ)
*pos |= IEEE80211_RADIOTAP_MCS_BW_40;
if (status->flag & RX_FLAG_HT_GF)
*pos |= IEEE80211_RADIOTAP_MCS_FMT_GF;
pos++;
*pos++ = status->rate_idx;
}
if (status->flag & RX_FLAG_AMPDU_DETAILS) {
u16 flags = 0;
/* ensure 4 byte alignment */
while ((pos - (u8 *)rthdr) & 3)
pos++;
rthdr->it_present |=
cpu_to_le32(1 << IEEE80211_RADIOTAP_AMPDU_STATUS);
put_unaligned_le32(status->ampdu_reference, pos);
pos += 4;
if (status->flag & RX_FLAG_AMPDU_REPORT_ZEROLEN)
flags |= IEEE80211_RADIOTAP_AMPDU_REPORT_ZEROLEN;
if (status->flag & RX_FLAG_AMPDU_IS_ZEROLEN)
flags |= IEEE80211_RADIOTAP_AMPDU_IS_ZEROLEN;
if (status->flag & RX_FLAG_AMPDU_LAST_KNOWN)
flags |= IEEE80211_RADIOTAP_AMPDU_LAST_KNOWN;
if (status->flag & RX_FLAG_AMPDU_IS_LAST)
flags |= IEEE80211_RADIOTAP_AMPDU_IS_LAST;
if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_ERROR)
flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_ERR;
if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_KNOWN;
put_unaligned_le16(flags, pos);
pos += 2;
if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
*pos++ = status->ampdu_delimiter_crc;
else
*pos++ = 0;
*pos++ = 0;
}
if (status->flag & RX_FLAG_VHT) {
u16 known = local->hw.radiotap_vht_details;
rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);
/* known field - how to handle 80+80? */
if (status->flag & RX_FLAG_80P80MHZ)
known &= ~IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
put_unaligned_le16(known, pos);
pos += 2;
/* flags */
if (status->flag & RX_FLAG_SHORT_GI)
*pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
pos++;
/* bandwidth */
if (status->flag & RX_FLAG_80MHZ)
*pos++ = 4;
else if (status->flag & RX_FLAG_80P80MHZ)
*pos++ = 0; /* marked not known above */
else if (status->flag & RX_FLAG_160MHZ)
*pos++ = 11;
else if (status->flag & RX_FLAG_40MHZ)
*pos++ = 1;
else /* 20 MHz */
*pos++ = 0;
/* MCS/NSS */
*pos = (status->rate_idx << 4) | status->vht_nss;
pos += 4;
/* coding field */
pos++;
/* group ID */
pos++;
/* partial_aid */
pos += 2;
}
if (status->vendor_radiotap_len) {
/* ensure 2 byte alignment for the vendor field as required */
if ((pos - (u8 *)rthdr) & 1)
*pos++ = 0;
*pos++ = status->vendor_radiotap_oui[0];
*pos++ = status->vendor_radiotap_oui[1];
*pos++ = status->vendor_radiotap_oui[2];
*pos++ = status->vendor_radiotap_subns;
put_unaligned_le16(status->vendor_radiotap_len, pos);
pos += 2;
/* align the actual payload as requested */
while ((pos - (u8 *)rthdr) & (status->vendor_radiotap_align - 1))
*pos++ = 0;
}
}
/*
* 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;
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.
*/
if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
present_fcs_len = FCS_LEN;
/* ensure hdr->frame_control and vendor radiotap data are in skb head */
if (!pskb_may_pull(origskb, 2 + status->vendor_radiotap_len)) {
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);
}
/* room for the radiotap header based on driver features */
needed_headroom = ieee80211_rx_radiotap_space(local, status);
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,
true);
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;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
int tid, seqno_idx, security_idx;
/* 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_CTL_A_MSDU_PRESENT)
status->rx_flags |= IEEE80211_RX_AMSDU;
seqno_idx = tid;
security_idx = tid;
} 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.
*/
seqno_idx = IEEE80211_NUM_TIDS;
security_idx = 0;
if (ieee80211_is_mgmt(hdr->frame_control))
security_idx = IEEE80211_NUM_TIDS;
tid = 0;
}
rx->seqno_idx = seqno_idx;
rx->security_idx = security_idx;
/* 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 between 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 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;
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 (ether_addr_equal(hdr->addr3, dev_addr))
return RX_DROP_MONITOR;
} else {
if (!ieee80211_has_a4(hdr->frame_control))
return RX_DROP_MONITOR;
if (ether_addr_equal(hdr->addr4, dev_addr))
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) != NL80211_PLINK_ESTAB) {
struct ieee80211_mgmt *mgmt;
if (!ieee80211_is_mgmt(hdr->frame_control))
return RX_DROP_MONITOR;
if (ieee80211_is_action(hdr->frame_control)) {
u8 category;
/* make sure category field is present */
if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE)
return RX_DROP_MONITOR;
mgmt = (struct ieee80211_mgmt *)hdr;
category = mgmt->u.action.category;
if (category != WLAN_CATEGORY_MESH_ACTION &&
category != WLAN_CATEGORY_SELF_PROTECTED)
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) ||
ieee80211_is_auth(hdr->frame_control))
return RX_CONTINUE;
return RX_DROP_MONITOR;
}
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_sub_if_data *sdata,
struct tid_ampdu_rx *tid_agg_rx,
int index)
{
struct ieee80211_local *local = sdata->local;
struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
struct ieee80211_rx_status *status;
lockdep_assert_held(&tid_agg_rx->reorder_lock);
if (!skb)
goto no_frame;
/* release the frame from the reorder ring buffer */
tid_agg_rx->stored_mpdu_num--;
tid_agg_rx->reorder_buf[index] = NULL;
status = IEEE80211_SKB_RXCB(skb);
status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
skb_queue_tail(&local->rx_skb_queue, 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_sub_if_data *sdata,
struct tid_ampdu_rx *tid_agg_rx,
u16 head_seq_num)
{
int index;
lockdep_assert_held(&tid_agg_rx->reorder_lock);
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(sdata, tid_agg_rx, index);
}
}
/*
* 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.
*
* Callers must hold tid_agg_rx->reorder_lock.
*/
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)
static void ieee80211_sta_reorder_release(struct ieee80211_sub_if_data *sdata,
struct tid_ampdu_rx *tid_agg_rx)
{
int index, j;
lockdep_assert_held(&tid_agg_rx->reorder_lock);
/* 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) {
/*
* No buffers ready to be released, but check whether any
* frames in the reorder buffer have timed out.
*/
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 (skipped &&
!time_after(jiffies, tid_agg_rx->reorder_time[j] +
HT_RX_REORDER_BUF_TIMEOUT))
goto set_release_timer;
ht_dbg_ratelimited(sdata,
"release an RX reorder frame due to timeout on earlier frames\n");
ieee80211_release_reorder_frame(sdata, tid_agg_rx, j);
/*
* 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(sdata, tid_agg_rx, index);
index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
tid_agg_rx->buf_size;
}
if (tid_agg_rx->stored_mpdu_num) {
j = index = seq_sub(tid_agg_rx->head_seq_num,
tid_agg_rx->ssn) % tid_agg_rx->buf_size;
for (; j != (index - 1) % tid_agg_rx->buf_size;
j = (j + 1) % tid_agg_rx->buf_size) {
if (tid_agg_rx->reorder_buf[j])
break;
}
set_release_timer:
mod_timer(&tid_agg_rx->reorder_timer,
tid_agg_rx->reorder_time[j] + 1 +
HT_RX_REORDER_BUF_TIMEOUT);
} else {
del_timer(&tid_agg_rx->reorder_timer);
}
}
/*
* 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_sub_if_data *sdata,
struct tid_ampdu_rx *tid_agg_rx,
struct sk_buff *skb)
{
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;
bool ret = true;
spin_lock(&tid_agg_rx->reorder_lock);
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);
goto out;
}
/*
* 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(sdata, tid_agg_rx,
head_seq_num);
}
/* 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);
goto out;
}
/*
* 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 it is first but there's something stored, we may be able
* to release frames after this one.
*/
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);
ret = false;
goto out;
}
/* 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++;
ieee80211_sta_reorder_release(sdata, tid_agg_rx);
out:
spin_unlock(&tid_agg_rx->reorder_lock);
return ret;
}
/*
* 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 *skb = rx->skb;
struct ieee80211_local *local = rx->local;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct sta_info *sta = rx->sta;
struct tid_ampdu_rx *tid_agg_rx;
u16 sc;
u8 tid, ack_policy;
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;
ack_policy = *ieee80211_get_qos_ctl(hdr) &
IEEE80211_QOS_CTL_ACK_POLICY_MASK;
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;
/* not part of a BA session */
if (ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK &&
ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_NORMAL)
goto dont_reorder;
/* not actually part of this BA session */
if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
goto dont_reorder;
/* new, potentially un-ordered, ampdu frame - process it */
/* reset session timer */
if (tid_agg_rx->timeout)
tid_agg_rx->last_rx = jiffies;
/* 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(rx->sdata, tid_agg_rx, skb))
return;
dont_reorder:
skb_queue_tail(&local->rx_skb_queue, 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;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
/* 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->seqno_idx] ==
hdr->seq_ctrl)) {
if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
rx->local->dot11FrameDuplicateCount++;
rx->sta->num_duplicates++;
}
return RX_DROP_UNUSABLE;
} else
rx->sta->last_seq_ctrl[rx->seqno_idx] = 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->sdata->vif.type != NL80211_IFTYPE_WDS &&
(!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_ASSOC)))) {
/*
* accept port control frames from the AP even when it's not
* yet marked ASSOC to prevent a race where we don't set the
* assoc bit quickly enough before it sends the first frame
*/
if (rx->sta && rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
ieee80211_is_data_present(hdr->frame_control)) {
unsigned int hdrlen;
__be16 ethertype;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (rx->skb->len < hdrlen + 8)
return RX_DROP_MONITOR;
skb_copy_bits(rx->skb, hdrlen + 6, ðertype, 2);
if (ethertype == rx->sdata->control_port_protocol)
return RX_CONTINUE;
}
if (rx->sdata->vif.type == NL80211_IFTYPE_AP &&
cfg80211_rx_spurious_frame(rx->sdata->dev,
hdr->addr2,
GFP_ATOMIC))
return RX_DROP_UNUSABLE;
return RX_DROP_MONITOR;