mac80211: adding 802.11n essential A-MSDU Rx capability

This patch adds the ability to receive and handle A-MSDU frames.

Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 125 insertions, 0 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 982f99672994..66b6cf3a62ac 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -155,6 +155,7 @@ struct ieee80211_txrx_data {
                         int load;
                         u32 tkip_iv32;
                         u16 tkip_iv16;
+                        u8  amsdu_frame;
                 } rx;
         } u;
 };
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 478d85563bdb..4525d7332c88 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -243,6 +243,10 @@ ieee80211_rx_h_parse_qos(struct ieee80211_txrx_data *rx)
                 u8 *qc = data + ieee80211_get_hdrlen(rx->fc) - QOS_CONTROL_LEN;
                 /* frame has qos control */
                 tid = qc[0] & QOS_CONTROL_TID_MASK;
+                if (qc[0] & IEEE80211_QOS_CONTROL_A_MSDU_PRESENT)
+                        rx->u.rx.amsdu_frame = 1;
+                else
+                        rx->u.rx.amsdu_frame = 0;
         } else {
                 if (unlikely((rx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_MGMT)) {
                         /* Separate TID for management frames */
@@ -1197,6 +1201,125 @@ ieee80211_deliver_skb(struct ieee80211_txrx_data *rx)
 }
 
 static ieee80211_txrx_result
+ieee80211_rx_h_amsdu(struct ieee80211_txrx_data *rx)
+{
+        struct net_device *dev = rx->dev;
+        struct ieee80211_local *local = rx->local;
+        u16 fc, ethertype;
+        u8 *payload;
+        struct sk_buff *skb = rx->skb, *frame = NULL;
+        const struct ethhdr *eth;
+        int remaining, err;
+        u8 dst[ETH_ALEN];
+        u8 src[ETH_ALEN];
+        DECLARE_MAC_BUF(mac);
+
+        fc = rx->fc;
+        if (unlikely((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA))
+                return TXRX_CONTINUE;
+
+        if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
+                return TXRX_DROP;
+
+        if (!rx->u.rx.amsdu_frame)
+                return TXRX_CONTINUE;
+
+        err = ieee80211_data_to_8023(rx);
+        if (unlikely(err))
+                return TXRX_DROP;
+
+        skb->dev = dev;
+
+        dev->stats.rx_packets++;
+        dev->stats.rx_bytes += skb->len;
+
+        /* skip the wrapping header */
+        eth = (struct ethhdr *) skb_pull(skb, sizeof(struct ethhdr));
+        if (!eth)
+                return TXRX_DROP;
+
+        while (skb != frame) {
+                u8 padding;
+                __be16 len = eth->h_proto;
+                unsigned int subframe_len = sizeof(struct ethhdr) + ntohs(len);
+
+                remaining = skb->len;
+                memcpy(dst, eth->h_dest, ETH_ALEN);
+                memcpy(src, eth->h_source, ETH_ALEN);
+
+                padding = ((4 - subframe_len) & 0x3);
+                /* the last MSDU has no padding */
+                if (subframe_len > remaining) {
+                        printk(KERN_DEBUG "%s: wrong buffer size", dev->name);
+                        return TXRX_DROP;
+                }
+
+                skb_pull(skb, sizeof(struct ethhdr));
+                /* if last subframe reuse skb */
+                if (remaining <= subframe_len + padding)
+                        frame = skb;
+                else {
+                        frame = dev_alloc_skb(local->hw.extra_tx_headroom +
+                                              subframe_len);
+
+                        if (frame == NULL)
+                                return TXRX_DROP;
+
+                        skb_reserve(frame, local->hw.extra_tx_headroom +
+                                    sizeof(struct ethhdr));
+                        memcpy(skb_put(frame, ntohs(len)), skb->data,
+                                ntohs(len));
+
+                        eth = (struct ethhdr *) skb_pull(skb, ntohs(len) +
+                                                        padding);
+                        if (!eth) {
+                                printk(KERN_DEBUG "%s: wrong buffer size ",
+                                       dev->name);
+                                dev_kfree_skb(frame);
+                                return TXRX_DROP;
+                        }
+                }
+
+                skb_set_network_header(frame, 0);
+                frame->dev = dev;
+                frame->priority = skb->priority;
+                rx->skb = frame;
+
+                if ((ieee80211_drop_802_1x_pae(rx, 0)) ||
+                    (ieee80211_drop_unencrypted(rx, 0))) {
+                        if (skb == frame) /* last frame */
+                                return TXRX_DROP;
+                        dev_kfree_skb(frame);
+                        continue;
+                }
+
+                payload = frame->data;
+                ethertype = (payload[6] << 8) | payload[7];
+
+                if (likely((compare_ether_addr(payload, rfc1042_header) == 0 &&
+                        ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
+                        compare_ether_addr(payload,
+                                           bridge_tunnel_header) == 0)) {
+                        /* remove RFC1042 or Bridge-Tunnel
+                         * encapsulation and replace EtherType */
+                        skb_pull(frame, 6);
+                        memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
+                        memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
+                } else {
+                        memcpy(skb_push(frame, sizeof(__be16)), &len,
+                                sizeof(__be16));
+                        memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
+                        memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
+                }
+
+
+                ieee80211_deliver_skb(rx);
+        }
+
+        return TXRX_QUEUED;
+}
+
+static ieee80211_txrx_result
 ieee80211_rx_h_data(struct ieee80211_txrx_data *rx)
 {
         struct net_device *dev = rx->dev;
@@ -1379,6 +1502,7 @@ ieee80211_rx_handler ieee80211_rx_handlers[] =
          * are not passed to user space by these functions
          */
         ieee80211_rx_h_remove_qos_control,
+        ieee80211_rx_h_amsdu,
         ieee80211_rx_h_data,
         ieee80211_rx_h_mgmt,
         NULL