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Commit 3d30d949 authored by Michael Wu's avatar Michael Wu Committed by John W. Linville
Browse files

mac80211: Add cooked monitor mode support 



This adds "cooked" monitor mode to mac80211. A monitor interface
in "cooked" mode will see all frames that mac80211 has not used
internally.

Signed-off-by: default avatarMichael Wu <flamingice@sourmilk.net>
Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 8944b79f

net/mac80211/ieee80211.c

+38 −29
Original line number Diff line number Diff line
@@ -239,6 +239,11 @@ static int ieee80211_open(struct net_device *dev) 
		/* no need to tell driver */

		break;

	case IEEE80211_IF_TYPE_MNTR:

		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {

			local->cooked_mntrs++;

			break;

		}



		/* must be before the call to ieee80211_configure_filter */

		local->monitors++;

		if (local->monitors == 1)
@@ -370,6 +375,11 @@ static int ieee80211_stop(struct net_device *dev) 
		/* no need to tell driver */

		break;

	case IEEE80211_IF_TYPE_MNTR:

		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {

			local->cooked_mntrs--;

			break;

		}



		local->monitors--;

		if (local->monitors == 0)

			local->hw.conf.flags &= ~IEEE80211_CONF_RADIOTAP;
@@ -1177,7 +1187,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb, 
	u16 frag, type;

	struct ieee80211_tx_status_rtap_hdr *rthdr;

	struct ieee80211_sub_if_data *sdata;

	int monitors;

	struct net_device *prev_dev = NULL;



	if (!status) {

		printk(KERN_ERR
@@ -1290,7 +1300,11 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb, 
	/* this was a transmitted frame, but now we want to reuse it */

	skb_orphan(skb);



	if (!local->monitors) {

	/*

	 * This is a bit racy but we can avoid a lot of work

	 * with this test...

	 */

	if (!local->monitors && !local->cooked_mntrs) {

		dev_kfree_skb(skb);

		return;

	}
@@ -1324,41 +1338,36 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb, 


	rthdr->data_retries = status->retry_count;



	rcu_read_lock();

	monitors = local->monitors;

	list_for_each_entry_rcu(sdata, &local->interfaces, list) {

		/*

		 * Using the monitors counter is possibly racy, but

		 * if the value is wrong we simply either clone the skb

		 * once too much or forget sending it to one monitor iface

		 * The latter case isn't nice but fixing the race is much

		 * more complicated.

		 */

		if (!monitors || !skb)

			goto out;



		if (sdata->vif.type == IEEE80211_IF_TYPE_MNTR) {

			if (!netif_running(sdata->dev))

				continue;

			monitors--;

			if (monitors)

				skb2 = skb_clone(skb, GFP_ATOMIC);

			else

				skb2 = NULL;

			skb->dev = sdata->dev;

	/* XXX: is this sufficient for BPF? */

	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);

			skb = skb2;



	rcu_read_lock();

	list_for_each_entry_rcu(sdata, &local->interfaces, list) {

		if (sdata->vif.type == IEEE80211_IF_TYPE_MNTR) {

			if (!netif_running(sdata->dev))

				continue;



			if (prev_dev) {

				skb2 = skb_clone(skb, GFP_ATOMIC);

				if (skb2) {

					skb2->dev = prev_dev;

					netif_rx(skb2);

				}

			}

 out:



			prev_dev = sdata->dev;

		}

	}

	if (prev_dev) {

		skb->dev = prev_dev;

		netif_rx(skb);

		skb = NULL;

	}

	rcu_read_unlock();

	if (skb)

	dev_kfree_skb(skb);

}

EXPORT_SYMBOL(ieee80211_tx_status);

net/mac80211/ieee80211_i.h

+2 −1
Original line number Diff line number Diff line
@@ -131,6 +131,7 @@ typedef unsigned __bitwise__ ieee80211_rx_result; 
#define IEEE80211_TXRXD_RXRA_MATCH		BIT(5)

#define IEEE80211_TXRXD_TX_INJECTED		BIT(6)

#define IEEE80211_TXRXD_RX_AMSDU		BIT(7)

#define IEEE80211_TXRXD_RX_CMNTR_REPORTED	BIT(8)

struct ieee80211_txrx_data {

	struct sk_buff *skb;

	struct net_device *dev;
@@ -419,7 +420,7 @@ struct ieee80211_local { 


	struct net_device *mdev; /* wmaster# - "master" 802.11 device */

	int open_count;

	int monitors;

	int monitors, cooked_mntrs;

	/* number of interfaces with corresponding FIF_ flags */

	int fif_fcsfail, fif_plcpfail, fif_control, fif_other_bss;

	unsigned int filter_flags; /* FIF_* */

net/mac80211/rx.c

+86 −1
Original line number Diff line number Diff line
@@ -223,6 +223,9 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, 
		if (sdata->vif.type != IEEE80211_IF_TYPE_MNTR)

			continue;



		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)

			continue;



		if (prev_dev) {

			skb2 = skb_clone(skb, GFP_ATOMIC);

			if (skb2) {
@@ -1520,6 +1523,86 @@ static void ieee80211_rx_michael_mic_report(struct net_device *dev, 
	rx->skb = NULL;

}



static void ieee80211_rx_cooked_monitor(struct ieee80211_txrx_data *rx)

{

	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;

		__le16 chan_freq;

		__le16 chan_flags;

	} __attribute__ ((packed)) *rthdr;

	struct sk_buff *skb = rx->skb, *skb2;

	struct net_device *prev_dev = NULL;

	struct ieee80211_rx_status *status = rx->u.rx.status;



	if (rx->flags & IEEE80211_TXRXD_RX_CMNTR_REPORTED)

		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_RATE) |

			    (1 << IEEE80211_RADIOTAP_CHANNEL));



	rthdr->rate = rx->u.rx.rate->bitrate / 5;

	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 (!netif_running(sdata->dev))

			continue;



		if (sdata->vif.type != IEEE80211_IF_TYPE_MNTR ||

		    !(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_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);

		skb = NULL;

	} else

		goto out_free_skb;



	rx->flags |= IEEE80211_TXRXD_RX_CMNTR_REPORTED;

	return;



 out_free_skb:

	dev_kfree_skb(skb);

}



typedef ieee80211_rx_result (*ieee80211_rx_handler)(struct ieee80211_txrx_data *);

static ieee80211_rx_handler ieee80211_rx_handlers[] =

{
@@ -1574,9 +1657,11 @@ static void ieee80211_invoke_rx_handlers(struct ieee80211_sub_if_data *sdata, 
	}



	switch (res) {

	case RX_CONTINUE:

	case RX_DROP_MONITOR:

		ieee80211_rx_cooked_monitor(rx);

		break;

	case RX_DROP_UNUSABLE:

	case RX_CONTINUE:

		dev_kfree_skb(rx->skb);

		break;

	}