[PATCH] ieee80211: Fix TKIP, repeated fragmentation problem, and payload_size reporting

tree 8428e9f510e6ad6c77baec89cb57374842abf733
parent d78bfd3ddae9c422dd350159110f9c4d7cfc50de
author Liu Hong <hong.liu@intel.com> 1124446520 -0500
committer James Ketrenos <jketreno@linux.intel.com> 1127313183 -0500

Fix TKIP, repeated fragmentation problem, and payload_size reporting

1. TKIP encryption
    Originally, TKIP encryption issues msdu + mpdu encryption on every
    fragment. Change the behavior to msdu encryption on the whole
    packet, then mpdu encryption on every fragment.

2. Avoid repeated fragmentation when !host_encrypt.
    We only need do fragmentation when using host encryption. Otherwise
    we only need pass the whole packet to driver, letting driver do the
    fragmentation.

3. change the txb->payload_size to correct value
    FW will use this value to determine whether to do fragmentation. If
    we pass the wrong value, fw may cut on the wrong bound which will
    make decryption fail when we do host encryption.

NOTE:  This requires changing drivers (hostap) that have
extra_prefix_len used within them (structure member name change).

Signed-off-by: Hong Liu <liu.hong@intel.com>
Signed-off-by: James Ketrenos <jketreno@linux.intel.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 83 insertions, 65 deletions

diff --git a/net/ieee80211/ieee80211_tx.c b/net/ieee80211/ieee80211_tx.c
index f505aa127e2..23a1f88de7c 100644
--- a/net/ieee80211/ieee80211_tx.c
+++ b/net/ieee80211/ieee80211_tx.c
@@ -128,7 +128,7 @@ payload of each frame is reduced to 492 bytes.
 static u8 P802_1H_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0xf8 };
 static u8 RFC1042_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0x00 };
 
-static inline int ieee80211_put_snap(u8 * data, u16 h_proto)
+static inline int ieee80211_copy_snap(u8 * data, u16 h_proto)
 {
 	struct ieee80211_snap_hdr *snap;
 	u8 *oui;
@@ -159,15 +159,9 @@ static inline int ieee80211_encrypt_fragment(struct ieee80211_device *ieee,
 
 	/* To encrypt, frame format is:
 	 * IV (4 bytes), clear payload (including SNAP), ICV (4 bytes) */
-
-	// PR: FIXME: Copied from hostap. Check fragmentation/MSDU/MPDU encryption.
-	/* Host-based IEEE 802.11 fragmentation for TX is not yet supported, so
-	 * call both MSDU and MPDU encryption functions from here. */
 	atomic_inc(&crypt->refcnt);
 	res = 0;
-	if (crypt->ops->encrypt_msdu)
-		res = crypt->ops->encrypt_msdu(frag, hdr_len, crypt->priv);
-	if (res == 0 && crypt->ops->encrypt_mpdu)
+	if (crypt->ops->encrypt_mpdu)
 		res = crypt->ops->encrypt_mpdu(frag, hdr_len, crypt->priv);
 
 	atomic_dec(&crypt->refcnt);
@@ -222,7 +216,7 @@ static struct ieee80211_txb *ieee80211_alloc_txb(int nr_frags, int txb_size,
 	return txb;
 }
 
-/* Incoming skb is converted to a txb which consist of
+/* Incoming skb is converted to a txb which consists of
  * a block of 802.11 fragment packets (stored as skbs) */
 int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 {
@@ -233,7 +227,7 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 	    rts_required;
 	unsigned long flags;
 	struct net_device_stats *stats = &ieee->stats;
-	int ether_type, encrypt, host_encrypt;
+	int ether_type, encrypt, host_encrypt, host_encrypt_msdu;
 	int bytes, fc, hdr_len;
 	struct sk_buff *skb_frag;
 	struct ieee80211_hdr_3addr header = {	/* Ensure zero initialized */
@@ -241,8 +235,8 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 		.seq_ctl = 0
 	};
 	u8 dest[ETH_ALEN], src[ETH_ALEN];
-
 	struct ieee80211_crypt_data *crypt;
+	int snapped = 0;
 
 	spin_lock_irqsave(&ieee->lock, flags);
 
@@ -266,6 +260,7 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 	encrypt = !(ether_type == ETH_P_PAE && ieee->ieee802_1x) &&
 	    ieee->sec.encrypt;
 	host_encrypt = ieee->host_encrypt && encrypt;
+	host_encrypt_msdu = ieee->host_encrypt_msdu && encrypt;
 
 	if (!encrypt && ieee->ieee802_1x &&
 	    ieee->drop_unencrypted && ether_type != ETH_P_PAE) {
@@ -291,14 +286,12 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	if (ieee->iw_mode == IW_MODE_INFRA) {
 		fc |= IEEE80211_FCTL_TODS;
-		/* To DS: Addr1 = BSSID, Addr2 = SA,
-		   Addr3 = DA */
+		/* To DS: Addr1 = BSSID, Addr2 = SA, Addr3 = DA */
 		memcpy(header.addr1, ieee->bssid, ETH_ALEN);
 		memcpy(header.addr2, src, ETH_ALEN);
 		memcpy(header.addr3, dest, ETH_ALEN);
 	} else if (ieee->iw_mode == IW_MODE_ADHOC) {
-		/* not From/To DS: Addr1 = DA, Addr2 = SA,
-		   Addr3 = BSSID */
+		/* not From/To DS: Addr1 = DA, Addr2 = SA, Addr3 = BSSID */
 		memcpy(header.addr1, dest, ETH_ALEN);
 		memcpy(header.addr2, src, ETH_ALEN);
 		memcpy(header.addr3, ieee->bssid, ETH_ALEN);
@@ -306,42 +299,75 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 	header.frame_ctl = cpu_to_le16(fc);
 	hdr_len = IEEE80211_3ADDR_LEN;
 
-	/* Determine fragmentation size based on destination (multicast
-	 * and broadcast are not fragmented) */
-	if (is_multicast_ether_addr(dest) || is_broadcast_ether_addr(dest))
-		frag_size = MAX_FRAG_THRESHOLD;
-	else
-		frag_size = ieee->fts;
+	/* Encrypt msdu first on the whole data packet. */
+	if ((host_encrypt || host_encrypt_msdu) &&
+	    crypt && crypt->ops && crypt->ops->encrypt_msdu) {
+		int res = 0;
+		int len = bytes + hdr_len + crypt->ops->extra_msdu_prefix_len +
+		    crypt->ops->extra_msdu_postfix_len;
+		struct sk_buff *skb_new = dev_alloc_skb(len);
+		if (unlikely(!skb_new))
+			goto failed;
+		skb_reserve(skb_new, crypt->ops->extra_msdu_prefix_len);
+		memcpy(skb_put(skb_new, hdr_len), &header, hdr_len);
+		snapped = 1;
+		ieee80211_copy_snap(skb_put(skb_new, SNAP_SIZE + sizeof(u16)),
+				    ether_type);
+		memcpy(skb_put(skb_new, skb->len), skb->data, skb->len);
+		res = crypt->ops->encrypt_msdu(skb_new, hdr_len, crypt->priv);
+		if (res < 0) {
+			IEEE80211_ERROR("msdu encryption failed\n");
+			dev_kfree_skb_any(skb_new);
+			goto failed;
+		}
+		dev_kfree_skb_any(skb);
+		skb = skb_new;
+		bytes += crypt->ops->extra_msdu_prefix_len +
+		    crypt->ops->extra_msdu_postfix_len;
+		skb_pull(skb, hdr_len);
+	}
 
-	/* Determine amount of payload per fragment.  Regardless of if
-	 * this stack is providing the full 802.11 header, one will
-	 * eventually be affixed to this fragment -- so we must account for
-	 * it when determining the amount of payload space. */
-	bytes_per_frag = frag_size - IEEE80211_3ADDR_LEN;
-	if (ieee->config &
-	    (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
-		bytes_per_frag -= IEEE80211_FCS_LEN;
+	if (host_encrypt || ieee->host_open_frag) {
+		/* Determine fragmentation size based on destination (multicast
+		 * and broadcast are not fragmented) */
+		if (is_multicast_ether_addr(dest))
+			frag_size = MAX_FRAG_THRESHOLD;
+		else
+			frag_size = ieee->fts;
+
+		/* Determine amount of payload per fragment.  Regardless of if
+		 * this stack is providing the full 802.11 header, one will
+		 * eventually be affixed to this fragment -- so we must account
+		 * for it when determining the amount of payload space. */
+		bytes_per_frag = frag_size - IEEE80211_3ADDR_LEN;
+		if (ieee->config &
+		    (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
+			bytes_per_frag -= IEEE80211_FCS_LEN;
 
-	/* Each fragment may need to have room for encryptiong pre/postfix */
-	if (host_encrypt)
-		bytes_per_frag -= crypt->ops->extra_prefix_len +
-		    crypt->ops->extra_postfix_len;
-
-	/* Number of fragments is the total bytes_per_frag /
-	 * payload_per_fragment */
-	nr_frags = bytes / bytes_per_frag;
-	bytes_last_frag = bytes % bytes_per_frag;
-	if (bytes_last_frag)
-		nr_frags++;
-	else
-		bytes_last_frag = bytes_per_frag;
+		/* Each fragment may need to have room for encryptiong
+		 * pre/postfix */
+		if (host_encrypt)
+			bytes_per_frag -= crypt->ops->extra_mpdu_prefix_len +
+			    crypt->ops->extra_mpdu_postfix_len;
+
+		/* Number of fragments is the total
+		 * bytes_per_frag / payload_per_fragment */
+		nr_frags = bytes / bytes_per_frag;
+		bytes_last_frag = bytes % bytes_per_frag;
+		if (bytes_last_frag)
+			nr_frags++;
+		else
+			bytes_last_frag = bytes_per_frag;
+	} else {
+		nr_frags = 1;
+		bytes_per_frag = bytes_last_frag = bytes;
+		frag_size = bytes + IEEE80211_3ADDR_LEN;
+	}
 
 	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,
@@ -353,7 +379,11 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto failed;
 	}
 	txb->encrypted = encrypt;
-	txb->payload_size = bytes;
+	if (host_encrypt)
+		txb->payload_size = frag_size * (nr_frags - 1) +
+		    bytes_last_frag;
+	else
+		txb->payload_size = bytes;
 
 	if (rts_required) {
 		skb_frag = txb->fragments[0];
@@ -385,7 +415,8 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 		skb_frag = txb->fragments[i];
 
 		if (host_encrypt)
-			skb_reserve(skb_frag, crypt->ops->extra_prefix_len);
+			skb_reserve(skb_frag,
+				    crypt->ops->extra_mpdu_prefix_len);
 
 		frag_hdr =
 		    (struct ieee80211_hdr_3addr *)skb_put(skb_frag, hdr_len);
@@ -402,11 +433,10 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 			bytes = bytes_last_frag;
 		}
 
-		/* Put a SNAP header on the first fragment */
-		if (i == 0) {
-			ieee80211_put_snap(skb_put
-					   (skb_frag, SNAP_SIZE + sizeof(u16)),
-					   ether_type);
+		if (i == 0 && !snapped) {
+			ieee80211_copy_snap(skb_put
+					    (skb_frag, SNAP_SIZE + sizeof(u16)),
+					    ether_type);
 			bytes -= SNAP_SIZE + sizeof(u16);
 		}
 
@@ -420,19 +450,6 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 		if (host_encrypt)
 			ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len);
 
-		/* ipw2200/2915 Hardware encryption doesn't support TKIP MIC */
-		if (!ieee->host_encrypt && encrypt &&
-		    (ieee->sec.level == SEC_LEVEL_2) &&
-		    crypt && crypt->ops && crypt->ops->encrypt_msdu) {
-			int res = 0;
-			res = crypt->ops->encrypt_msdu(skb_frag, hdr_len,
-						       crypt->priv);
-			if (res < 0) {
-				IEEE80211_ERROR("TKIP MIC encryption failed\n");
-				goto failed;
-			}
-		}
-
 		if (ieee->config &
 		    (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
 			skb_put(skb_frag, 4);
@@ -444,7 +461,8 @@ int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 	dev_kfree_skb_any(skb);
 
 	if (txb) {
-		if ((*ieee->hard_start_xmit) (txb, dev) == 0) {
+		int ret = (*ieee->hard_start_xmit) (txb, dev);
+		if (ret == 0) {
 			stats->tx_packets++;
 			stats->tx_bytes += txb->payload_size;
 			return 0;