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 3a3112f17832..b1fc112152c9 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;
         }