[PATCH] ieee80211: adds support for the creation of RTS packets

tree b45c9c1017fd23216bfbe71e441aed9aa297fc84
parent 04aacdd71e904656a304d923bdcf57ad3bd2b254
author Ivo van Doorn <IvDoorn@gmail.com> 1124445405 -0500
committer James Ketrenos <jketreno@linux.intel.com> 1127313029 -0500

This patch adds support for the creation of RTS packets when the
config flag CFG_IEEE80211_RTS has been set.
Signed-Off-By: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: James Ketrenos <jketreno@linux.intel.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

include/net/ieee80211.h

@@ -690,6 +690,7 @@ enum ieee80211_state {
 
 #define CFG_IEEE80211_RESERVE_FCS (1<<0)
 #define CFG_IEEE80211_COMPUTE_FCS (1<<1)
+#define CFG_IEEE80211_RTS (1<<2)
 
 struct ieee80211_device {
 	struct net_device *dev;
@@ -747,6 +748,7 @@ struct ieee80211_device {
 	struct ieee80211_frag_entry frag_cache[IEEE80211_FRAG_CACHE_LEN];
 	unsigned int frag_next_idx;
 	u16 fts;		/* Fragmentation Threshold */
+	u16 rts;		/* RTS threshold */
 
 	/* Association info */
 	u8 bssid[ETH_ALEN];

net/ieee80211/ieee80211_module.c

@@ -126,6 +126,7 @@ struct net_device *alloc_ieee80211(int sizeof_priv)
 
 	/* Default fragmentation threshold is maximum payload size */
 	ieee->fts = DEFAULT_FTS;
+	ieee->rts = DEFAULT_FTS;
 	ieee->scan_age = DEFAULT_MAX_SCAN_AGE;
 	ieee->open_wep = 1;
 

net/ieee80211/ieee80211_tx.c

@@ -222,13 +222,15 @@ static struct ieee80211_txb *ieee80211_alloc_txb(int nr_frags, int txb_size,
 	return txb;
 }
 
-/* SKBs are added to the ieee->tx_queue. */
+/* Incoming skb is converted to a txb which consist of
+ * a block of 802.11 fragment packets (stored as skbs) */
 int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ieee80211_device *ieee = netdev_priv(dev);
 	struct ieee80211_txb *txb = NULL;
 	struct ieee80211_hdr_3addr *frag_hdr;
-	int i, bytes_per_frag, nr_frags, bytes_last_frag, frag_size;
+	int i, bytes_per_frag, nr_frags, bytes_last_frag, frag_size,
+	    rts_required;
 	unsigned long flags;
 	struct net_device_stats *stats = &ieee->stats;
 	int ether_type, encrypt, host_encrypt;
@@ -334,6 +336,13 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 	else
 		bytes_last_frag = bytes_per_frag;
 
+	rts_required = (frag_size > ieee->rts
+			&& ieee->config & CFG_IEEE80211_RTS);
+	if (rts_required)
+		nr_frags++;
+	else
+		bytes_last_frag = bytes_per_frag;
+
 	/* When we allocate the TXB we allocate enough space for the reserve
 	 * and full fragment bytes (bytes_per_frag doesn't include prefix,
 	 * postfix, header, FCS, etc.) */
@@ -346,7 +355,33 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 	txb->encrypted = encrypt;
 	txb->payload_size = bytes;
 
-	for (i = 0; i < nr_frags; i++) {
+	if (rts_required) {
+		skb_frag = txb->fragments[0];
+		frag_hdr =
+		    (struct ieee80211_hdr_3addr *)skb_put(skb_frag, hdr_len);
+
+		/*
+		 * Set header frame_ctl to the RTS.
+		 */
+		header.frame_ctl =
+		    cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS);
+		memcpy(frag_hdr, &header, hdr_len);
+
+		/*
+		 * Restore header frame_ctl to the original data setting.
+		 */
+		header.frame_ctl = cpu_to_le16(fc);
+
+		if (ieee->config &
+		    (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
+			skb_put(skb_frag, 4);
+
+		txb->rts_included = 1;
+		i = 1;
+	} else
+		i = 0;
+
+	for (; i < nr_frags; i++) {
 		skb_frag = txb->fragments[i];
 
 		if (host_encrypt)