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@xxxxxxxxxxxxxxxx>
---
net/mac80211/rx.c | 350 ++++++++++++++++++++++++++++++++++--------------------
1 file changed, 226 insertions(+), 124 deletions(-)
--- wireless-dev.orig/net/mac80211/rx.c 2007-09-25 23:28:22.951572917 +0200
+++ wireless-dev/net/mac80211/rx.c 2007-09-25 23:29:33.141601345 +0200
@@ -25,6 +25,207 @@
#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,
+ int rtap_len)
+{
+ skb_pull(skb, rtap_len);
+
+ if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
+ if (likely(skb->len > FCS_LEN))
+ skb_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 ieee80211_rx_status *status,
+ struct sk_buff *skb,
+ int present_fcs_len,
+ int radiotap_len)
+{
+ 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 + radiotap_len))
+ return 1;
+ if ((hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_FTYPE)) ==
+ cpu_to_le16(IEEE80211_FTYPE_CTL))
+ return 1;
+ return 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_rx_status *status)
+{
+ struct ieee80211_sub_if_data *sdata;
+ struct ieee80211_rate *rate;
+ int needed_headroom = 0;
+ struct ieee80211_rtap_hdr {
+ struct ieee80211_radiotap_header hdr;
+ u8 flags;
+ u8 rate;
+ __le16 chan_freq;
+ __le16 chan_flags;
+ u8 antsignal;
+ u8 padding_for_rxflags;
+ __le16 rx_flags;
+ } __attribute__ ((packed)) *rthdr;
+ struct sk_buff *skb, *skb2;
+ struct net_device *prev_dev = NULL;
+ int present_fcs_len = 0;
+ int rtap_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 (status->flag & RX_FLAG_RADIOTAP)
+ rtap_len = ieee80211_get_radiotap_len(origskb->data);
+ else
+ needed_headroom = sizeof(*rthdr);
+
+ if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
+ present_fcs_len = FCS_LEN;
+
+ if (!local->monitors) {
+ if (should_drop_frame(status, origskb, present_fcs_len,
+ rtap_len)) {
+ dev_kfree_skb(origskb);
+ return NULL;
+ }
+
+ return remove_monitor_info(local, origskb, rtap_len);
+ }
+
+ if (should_drop_frame(status, origskb, present_fcs_len, rtap_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, sizeof(*rthdr), 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, rtap_len);
+
+ if (!skb)
+ return origskb;
+ }
+
+ /* if necessary, prepend radiotap information */
+ if (!(status->flag & RX_FLAG_RADIOTAP)) {
+ 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_RATE) |
+ (1 << IEEE80211_RADIOTAP_CHANNEL) |
+ (1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL) |
+ (1 << IEEE80211_RADIOTAP_RX_FLAGS));
+ rthdr->flags = local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS ?
+ IEEE80211_RADIOTAP_F_FCS : 0;
+
+ /* FIXME: when radiotap gets a 'bad PLCP' flag use it here */
+ rthdr->rx_flags = 0;
+ if (status->flag &
+ (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
+ rthdr->rx_flags |=
+ cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS);
+
+ rate = ieee80211_get_rate(local, status->phymode,
+ status->rate);
+ if (rate)
+ rthdr->rate = rate->rate / 5;
+
+ rthdr->chan_freq = cpu_to_le16(status->freq);
+
+ if (status->phymode == MODE_IEEE80211A)
+ 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);
+
+ rthdr->antsignal = status->ssi;
+ }
+
+ 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 (!netif_running(sdata->dev))
+ continue;
+
+ if (sdata->type != IEEE80211_IF_TYPE_MNTR)
+ continue;
+
+ if (prev_dev) {
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (skb2) {
+ skb2->dev = prev_dev;
+ netif_rx(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_rx(skb);
+ } else
+ dev_kfree_skb(skb);
+
+ return origskb;
+}
+
+
/* pre-rx handlers
*
* these don't have dev/sdata fields in the rx data
@@ -132,100 +333,6 @@ ieee80211_rx_h_if_stats(struct ieee80211
return TXRX_CONTINUE;
}
-static void
-ieee80211_rx_monitor(struct net_device *dev, struct sk_buff *skb,
- struct ieee80211_rx_status *status)
-{
- struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
- struct ieee80211_rate *rate;
- struct ieee80211_rtap_hdr {
- struct ieee80211_radiotap_header hdr;
- u8 flags;
- u8 rate;
- __le16 chan_freq;
- __le16 chan_flags;
- u8 antsignal;
- u8 padding_for_rxflags;
- __le16 rx_flags;
- } __attribute__ ((packed)) *rthdr;
-
- skb->dev = dev;
-
- if (status->flag & RX_FLAG_RADIOTAP)
- goto out;
-
- if (skb_headroom(skb) < sizeof(*rthdr)) {
- I802_DEBUG_INC(local->rx_expand_skb_head);
- if (pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC)) {
- dev_kfree_skb(skb);
- return;
- }
- }
-
- rthdr = (struct ieee80211_rtap_hdr *) 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_RATE) |
- (1 << IEEE80211_RADIOTAP_CHANNEL) |
- (1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL) |
- (1 << IEEE80211_RADIOTAP_RX_FLAGS));
- rthdr->flags = local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS ?
- IEEE80211_RADIOTAP_F_FCS : 0;
-
- /* FIXME: when radiotap gets a 'bad PLCP' flag use it here */
- rthdr->rx_flags = 0;
- if (status->flag &
- (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
- rthdr->rx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS);
-
- rate = ieee80211_get_rate(local, status->phymode, status->rate);
- if (rate)
- rthdr->rate = rate->rate / 5;
-
- rthdr->chan_freq = cpu_to_le16(status->freq);
- rthdr->chan_flags =
- status->phymode == MODE_IEEE80211A ?
- cpu_to_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ) :
- cpu_to_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ);
- rthdr->antsignal = status->ssi;
-
- out:
- dev->stats.rx_packets++;
- dev->stats.rx_bytes += skb->len;
-
- skb_set_mac_header(skb, 0);
- skb->ip_summed = CHECKSUM_UNNECESSARY;
- skb->pkt_type = PACKET_OTHERHOST;
- skb->protocol = htons(ETH_P_802_2);
- memset(skb->cb, 0, sizeof(skb->cb));
- netif_rx(skb);
-}
-
-static ieee80211_txrx_result
-ieee80211_rx_h_monitor(struct ieee80211_txrx_data *rx)
-{
- if (rx->sdata->type == IEEE80211_IF_TYPE_MNTR) {
- ieee80211_rx_monitor(rx->dev, rx->skb, rx->u.rx.status);
- return TXRX_QUEUED;
- }
-
- /*
- * Drop frames with failed FCS/PLCP checksums here, they are only
- * relevant for monitor mode, the rest of the stack should never
- * see them.
- */
- if (rx->u.rx.status->flag &
- (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
- return TXRX_DROP;
-
- if (rx->u.rx.status->flag & RX_FLAG_RADIOTAP)
- skb_pull(rx->skb, ieee80211_get_radiotap_len(rx->skb->data));
-
- return TXRX_CONTINUE;
-}
-
static ieee80211_txrx_result
ieee80211_rx_h_passive_scan(struct ieee80211_txrx_data *rx)
{
@@ -266,10 +373,6 @@ ieee80211_rx_h_check(struct ieee80211_tx
rx->sta->last_seq_ctrl[rx->u.rx.queue] = hdr->seq_ctrl;
}
- if ((rx->local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) &&
- rx->skb->len > FCS_LEN)
- skb_trim(rx->skb, rx->skb->len - FCS_LEN);
-
if (unlikely(rx->skb->len < 16)) {
I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
return TXRX_DROP;
@@ -1264,7 +1367,6 @@ static void ieee80211_rx_michael_mic_rep
ieee80211_rx_handler ieee80211_rx_handlers[] =
{
ieee80211_rx_h_if_stats,
- ieee80211_rx_h_monitor,
ieee80211_rx_h_passive_scan,
ieee80211_rx_h_check,
ieee80211_rx_h_load_key,
@@ -1371,16 +1473,10 @@ void __ieee80211_rx(struct ieee80211_hw
struct ieee80211_hdr *hdr;
struct ieee80211_txrx_data rx;
u16 type;
- int radiotap_len = 0, prepres;
+ int prepres;
struct ieee80211_sub_if_data *prev = NULL;
struct sk_buff *skb_new;
u8 *bssid;
- int bogon;
-
- if (status->flag & RX_FLAG_RADIOTAP) {
- radiotap_len = ieee80211_get_radiotap_len(skb->data);
- skb_pull(skb, radiotap_len);
- }
/*
* key references and virtual interfaces are protected using RCU
@@ -1389,30 +1485,35 @@ void __ieee80211_rx(struct ieee80211_hw
*/
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, status);
+ if (!skb) {
+ rcu_read_unlock();
+ return;
+ }
+
hdr = (struct ieee80211_hdr *) skb->data;
memset(&rx, 0, sizeof(rx));
rx.skb = skb;
rx.local = local;
rx.u.rx.status = status;
- rx.fc = skb->len >= 2 ? le16_to_cpu(hdr->frame_control) : 0;
+ rx.fc = le16_to_cpu(hdr->frame_control);
type = rx.fc & IEEE80211_FCTL_FTYPE;
- bogon = status->flag & (RX_FLAG_FAILED_FCS_CRC |
- RX_FLAG_FAILED_PLCP_CRC);
-
- if (!bogon && (type == IEEE80211_FTYPE_DATA ||
- type == IEEE80211_FTYPE_MGMT))
+ if (type == IEEE80211_FTYPE_DATA || type == IEEE80211_FTYPE_MGMT)
local->dot11ReceivedFragmentCount++;
- if (!bogon && skb->len >= 16) {
- sta = rx.sta = sta_info_get(local, hdr->addr2);
- if (sta) {
- rx.dev = rx.sta->dev;
- rx.sdata = IEEE80211_DEV_TO_SUB_IF(rx.dev);
- }
- } else
- sta = rx.sta = NULL;
+ sta = rx.sta = sta_info_get(local, hdr->addr2);
+ if (sta) {
+ rx.dev = rx.sta->dev;
+ rx.sdata = IEEE80211_DEV_TO_SUB_IF(rx.dev);
+ }
if ((status->flag & RX_FLAG_MMIC_ERROR)) {
ieee80211_rx_michael_mic_report(local->mdev, hdr, sta, &rx);
@@ -1427,7 +1528,6 @@ void __ieee80211_rx(struct ieee80211_hw
goto end;
skb = rx.skb;
- skb_push(skb, radiotap_len);
if (sta && !(sta->flags & (WLAN_STA_WDS | WLAN_STA_ASSOC_AP)) &&
!local->iff_promiscs && !is_multicast_ether_addr(hdr->addr1)) {
rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
@@ -1438,14 +1538,16 @@ void __ieee80211_rx(struct ieee80211_hw
return;
}
- bssid = ieee80211_get_bssid(hdr, skb->len - radiotap_len);
+ bssid = ieee80211_get_bssid(hdr, skb->len);
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
- rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
-
if (!netif_running(sdata->dev))
continue;
+ if (sdata->type == IEEE80211_IF_TYPE_MNTR)
+ continue;
+
+ rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
prepres = prepare_for_handlers(sdata, bssid, &rx, hdr);
/* prepare_for_handlers can change sta */
sta = rx.sta;
--
-
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