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: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 86 insertions, 1 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 3a3112f1783..b1fc112152c 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -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;
 	}