[PATCH] mac80211: pass frames to monitor interfaces early
This makes mac80211 pass all frames to monitor interfaces early before all receive processing with the benefit that only a single copy needs to be made, all monitors can receive clones of the skb and if the frame will be discarded we don't even need to make a single copy. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg
David S. Miller
parent
5b2812e925
commit
b2e7771e55
1 changed files with 226 additions and 124 deletions
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@ -25,6 +25,207 @@
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#include "tkip.h"
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#include "wme.h"
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/*
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* monitor mode reception
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*
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* This function cleans up the SKB, i.e. it removes all the stuff
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* only useful for monitoring.
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*/
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static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
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struct sk_buff *skb,
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int rtap_len)
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{
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skb_pull(skb, rtap_len);
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if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
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if (likely(skb->len > FCS_LEN))
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skb_trim(skb, skb->len - FCS_LEN);
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else {
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/* driver bug */
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WARN_ON(1);
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dev_kfree_skb(skb);
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skb = NULL;
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}
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}
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return skb;
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}
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static inline int should_drop_frame(struct ieee80211_rx_status *status,
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struct sk_buff *skb,
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int present_fcs_len,
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int radiotap_len)
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{
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
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if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
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return 1;
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if (unlikely(skb->len < 16 + present_fcs_len + radiotap_len))
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return 1;
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if ((hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_FTYPE)) ==
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cpu_to_le16(IEEE80211_FTYPE_CTL))
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return 1;
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return 0;
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}
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/*
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* This function copies a received frame to all monitor interfaces and
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* returns a cleaned-up SKB that no longer includes the FCS nor the
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* radiotap header the driver might have added.
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*/
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static struct sk_buff *
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ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
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struct ieee80211_rx_status *status)
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{
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struct ieee80211_sub_if_data *sdata;
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struct ieee80211_rate *rate;
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int needed_headroom = 0;
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struct ieee80211_rtap_hdr {
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struct ieee80211_radiotap_header hdr;
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u8 flags;
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u8 rate;
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__le16 chan_freq;
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__le16 chan_flags;
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u8 antsignal;
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u8 padding_for_rxflags;
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__le16 rx_flags;
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} __attribute__ ((packed)) *rthdr;
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struct sk_buff *skb, *skb2;
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struct net_device *prev_dev = NULL;
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int present_fcs_len = 0;
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int rtap_len = 0;
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/*
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* First, we may need to make a copy of the skb because
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* (1) we need to modify it for radiotap (if not present), and
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* (2) the other RX handlers will modify the skb we got.
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*
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* We don't need to, of course, if we aren't going to return
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* the SKB because it has a bad FCS/PLCP checksum.
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*/
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if (status->flag & RX_FLAG_RADIOTAP)
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rtap_len = ieee80211_get_radiotap_len(origskb->data);
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else
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needed_headroom = sizeof(*rthdr);
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if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
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present_fcs_len = FCS_LEN;
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if (!local->monitors) {
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if (should_drop_frame(status, origskb, present_fcs_len,
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rtap_len)) {
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dev_kfree_skb(origskb);
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return NULL;
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}
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return remove_monitor_info(local, origskb, rtap_len);
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}
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if (should_drop_frame(status, origskb, present_fcs_len, rtap_len)) {
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/* only need to expand headroom if necessary */
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skb = origskb;
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origskb = NULL;
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/*
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* This shouldn't trigger often because most devices have an
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* RX header they pull before we get here, and that should
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* be big enough for our radiotap information. We should
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* probably export the length to drivers so that we can have
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* them allocate enough headroom to start with.
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*/
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if (skb_headroom(skb) < needed_headroom &&
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pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC)) {
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dev_kfree_skb(skb);
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return NULL;
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}
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} else {
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/*
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* Need to make a copy and possibly remove radiotap header
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* and FCS from the original.
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*/
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skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC);
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origskb = remove_monitor_info(local, origskb, rtap_len);
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if (!skb)
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return origskb;
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}
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/* if necessary, prepend radiotap information */
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if (!(status->flag & RX_FLAG_RADIOTAP)) {
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rthdr = (void *) skb_push(skb, sizeof(*rthdr));
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memset(rthdr, 0, sizeof(*rthdr));
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rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
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rthdr->hdr.it_present =
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cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
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(1 << IEEE80211_RADIOTAP_RATE) |
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(1 << IEEE80211_RADIOTAP_CHANNEL) |
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(1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL) |
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(1 << IEEE80211_RADIOTAP_RX_FLAGS));
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rthdr->flags = local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS ?
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IEEE80211_RADIOTAP_F_FCS : 0;
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/* FIXME: when radiotap gets a 'bad PLCP' flag use it here */
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rthdr->rx_flags = 0;
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if (status->flag &
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(RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
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rthdr->rx_flags |=
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cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS);
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rate = ieee80211_get_rate(local, status->phymode,
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status->rate);
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if (rate)
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rthdr->rate = rate->rate / 5;
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rthdr->chan_freq = cpu_to_le16(status->freq);
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if (status->phymode == MODE_IEEE80211A)
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rthdr->chan_flags =
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cpu_to_le16(IEEE80211_CHAN_OFDM |
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IEEE80211_CHAN_5GHZ);
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else
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rthdr->chan_flags =
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cpu_to_le16(IEEE80211_CHAN_DYN |
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IEEE80211_CHAN_2GHZ);
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rthdr->antsignal = status->ssi;
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}
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skb_set_mac_header(skb, 0);
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skb->ip_summed = CHECKSUM_UNNECESSARY;
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skb->pkt_type = PACKET_OTHERHOST;
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skb->protocol = htons(ETH_P_802_2);
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list_for_each_entry_rcu(sdata, &local->interfaces, list) {
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if (!netif_running(sdata->dev))
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continue;
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if (sdata->type != IEEE80211_IF_TYPE_MNTR)
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continue;
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if (prev_dev) {
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skb2 = skb_clone(skb, GFP_ATOMIC);
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if (skb2) {
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skb2->dev = prev_dev;
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netif_rx(skb2);
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}
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}
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prev_dev = sdata->dev;
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sdata->dev->stats.rx_packets++;
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sdata->dev->stats.rx_bytes += skb->len;
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}
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if (prev_dev) {
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skb->dev = prev_dev;
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netif_rx(skb);
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} else
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dev_kfree_skb(skb);
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return origskb;
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}
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/* pre-rx handlers
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*
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* these don't have dev/sdata fields in the rx data
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@ -132,100 +333,6 @@ ieee80211_rx_h_if_stats(struct ieee80211_txrx_data *rx)
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return TXRX_CONTINUE;
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}
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static void
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ieee80211_rx_monitor(struct net_device *dev, struct sk_buff *skb,
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struct ieee80211_rx_status *status)
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{
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struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
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struct ieee80211_rate *rate;
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struct ieee80211_rtap_hdr {
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struct ieee80211_radiotap_header hdr;
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u8 flags;
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u8 rate;
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__le16 chan_freq;
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__le16 chan_flags;
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u8 antsignal;
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u8 padding_for_rxflags;
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__le16 rx_flags;
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} __attribute__ ((packed)) *rthdr;
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skb->dev = dev;
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if (status->flag & RX_FLAG_RADIOTAP)
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goto out;
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if (skb_headroom(skb) < sizeof(*rthdr)) {
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I802_DEBUG_INC(local->rx_expand_skb_head);
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if (pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC)) {
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dev_kfree_skb(skb);
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return;
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}
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}
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rthdr = (struct ieee80211_rtap_hdr *) skb_push(skb, sizeof(*rthdr));
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memset(rthdr, 0, sizeof(*rthdr));
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rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
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rthdr->hdr.it_present =
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cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
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(1 << IEEE80211_RADIOTAP_RATE) |
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(1 << IEEE80211_RADIOTAP_CHANNEL) |
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(1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL) |
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(1 << IEEE80211_RADIOTAP_RX_FLAGS));
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rthdr->flags = local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS ?
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IEEE80211_RADIOTAP_F_FCS : 0;
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/* FIXME: when radiotap gets a 'bad PLCP' flag use it here */
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rthdr->rx_flags = 0;
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if (status->flag &
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(RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
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rthdr->rx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS);
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rate = ieee80211_get_rate(local, status->phymode, status->rate);
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if (rate)
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rthdr->rate = rate->rate / 5;
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rthdr->chan_freq = cpu_to_le16(status->freq);
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rthdr->chan_flags =
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status->phymode == MODE_IEEE80211A ?
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cpu_to_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ) :
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cpu_to_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ);
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rthdr->antsignal = status->ssi;
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out:
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dev->stats.rx_packets++;
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dev->stats.rx_bytes += skb->len;
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skb_set_mac_header(skb, 0);
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skb->ip_summed = CHECKSUM_UNNECESSARY;
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skb->pkt_type = PACKET_OTHERHOST;
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skb->protocol = htons(ETH_P_802_2);
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memset(skb->cb, 0, sizeof(skb->cb));
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netif_rx(skb);
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}
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static ieee80211_txrx_result
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ieee80211_rx_h_monitor(struct ieee80211_txrx_data *rx)
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{
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if (rx->sdata->type == IEEE80211_IF_TYPE_MNTR) {
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ieee80211_rx_monitor(rx->dev, rx->skb, rx->u.rx.status);
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return TXRX_QUEUED;
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}
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/*
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* Drop frames with failed FCS/PLCP checksums here, they are only
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* relevant for monitor mode, the rest of the stack should never
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* see them.
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*/
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if (rx->u.rx.status->flag &
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(RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
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return TXRX_DROP;
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if (rx->u.rx.status->flag & RX_FLAG_RADIOTAP)
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skb_pull(rx->skb, ieee80211_get_radiotap_len(rx->skb->data));
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return TXRX_CONTINUE;
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}
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static ieee80211_txrx_result
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ieee80211_rx_h_passive_scan(struct ieee80211_txrx_data *rx)
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{
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@ -266,10 +373,6 @@ ieee80211_rx_h_check(struct ieee80211_txrx_data *rx)
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rx->sta->last_seq_ctrl[rx->u.rx.queue] = hdr->seq_ctrl;
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}
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if ((rx->local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) &&
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rx->skb->len > FCS_LEN)
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skb_trim(rx->skb, rx->skb->len - FCS_LEN);
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if (unlikely(rx->skb->len < 16)) {
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I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
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return TXRX_DROP;
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@ -1264,7 +1367,6 @@ static void ieee80211_rx_michael_mic_report(struct net_device *dev,
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ieee80211_rx_handler ieee80211_rx_handlers[] =
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{
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ieee80211_rx_h_if_stats,
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ieee80211_rx_h_monitor,
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ieee80211_rx_h_passive_scan,
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ieee80211_rx_h_check,
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ieee80211_rx_h_load_key,
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@ -1371,16 +1473,10 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
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struct ieee80211_hdr *hdr;
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struct ieee80211_txrx_data rx;
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u16 type;
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int radiotap_len = 0, prepres;
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int prepres;
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struct ieee80211_sub_if_data *prev = NULL;
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struct sk_buff *skb_new;
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u8 *bssid;
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int bogon;
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if (status->flag & RX_FLAG_RADIOTAP) {
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radiotap_len = ieee80211_get_radiotap_len(skb->data);
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skb_pull(skb, radiotap_len);
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}
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/*
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* key references and virtual interfaces are protected using RCU
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@ -1389,30 +1485,35 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
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*/
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rcu_read_lock();
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/*
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* Frames with failed FCS/PLCP checksum are not returned,
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* all other frames are returned without radiotap header
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* if it was previously present.
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* Also, frames with less than 16 bytes are dropped.
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*/
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skb = ieee80211_rx_monitor(local, skb, status);
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if (!skb) {
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rcu_read_unlock();
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return;
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}
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hdr = (struct ieee80211_hdr *) skb->data;
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memset(&rx, 0, sizeof(rx));
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rx.skb = skb;
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rx.local = local;
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rx.u.rx.status = status;
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rx.fc = skb->len >= 2 ? le16_to_cpu(hdr->frame_control) : 0;
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rx.fc = le16_to_cpu(hdr->frame_control);
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type = rx.fc & IEEE80211_FCTL_FTYPE;
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bogon = status->flag & (RX_FLAG_FAILED_FCS_CRC |
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RX_FLAG_FAILED_PLCP_CRC);
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if (!bogon && (type == IEEE80211_FTYPE_DATA ||
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type == IEEE80211_FTYPE_MGMT))
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if (type == IEEE80211_FTYPE_DATA || type == IEEE80211_FTYPE_MGMT)
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local->dot11ReceivedFragmentCount++;
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if (!bogon && skb->len >= 16) {
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sta = rx.sta = sta_info_get(local, hdr->addr2);
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if (sta) {
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rx.dev = rx.sta->dev;
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rx.sdata = IEEE80211_DEV_TO_SUB_IF(rx.dev);
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}
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} else
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sta = rx.sta = NULL;
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sta = rx.sta = sta_info_get(local, hdr->addr2);
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if (sta) {
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rx.dev = rx.sta->dev;
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rx.sdata = IEEE80211_DEV_TO_SUB_IF(rx.dev);
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}
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if ((status->flag & RX_FLAG_MMIC_ERROR)) {
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ieee80211_rx_michael_mic_report(local->mdev, hdr, sta, &rx);
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@ -1427,7 +1528,6 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
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goto end;
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skb = rx.skb;
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skb_push(skb, radiotap_len);
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if (sta && !(sta->flags & (WLAN_STA_WDS | WLAN_STA_ASSOC_AP)) &&
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!local->iff_promiscs && !is_multicast_ether_addr(hdr->addr1)) {
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rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
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@ -1438,14 +1538,16 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
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return;
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}
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bssid = ieee80211_get_bssid(hdr, skb->len - radiotap_len);
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bssid = ieee80211_get_bssid(hdr, skb->len);
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list_for_each_entry_rcu(sdata, &local->interfaces, list) {
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rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
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if (!netif_running(sdata->dev))
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continue;
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if (sdata->type == IEEE80211_IF_TYPE_MNTR)
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continue;
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rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
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prepres = prepare_for_handlers(sdata, bssid, &rx, hdr);
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/* prepare_for_handlers can change sta */
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sta = rx.sta;
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