[NET] ieee80211 subsystem

Contributors:
Host AP contributors
James Ketrenos <jketreno@linux.intel.com>
Francois Romieu <romieu@fr.zoreil.com>
Adrian Bunk <bunk@stusta.de>
Matthew Galgoci <mgalgoci@parcelfarce.linux.th
eplanet.co.uk>

1 files changed, 448 insertions, 0 deletions

diff --git a/net/ieee80211/ieee80211_tx.c b/net/ieee80211/ieee80211_tx.c
new file mode 100644
index 0000000..d70e6b8
--- /dev/null
+++ b/net/ieee80211/ieee80211_tx.c
@@ -0,0 +1,448 @@
+/******************************************************************************
+
+  Copyright(c) 2003 - 2004 Intel Corporation. All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify it
+  under the terms of version 2 of the GNU General Public License as
+  published by the Free Software Foundation.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+  more details.
+
+  You should have received a copy of the GNU General Public License along with
+  this program; if not, write to the Free Software Foundation, Inc., 59
+  Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+  The full GNU General Public License is included in this distribution in the
+  file called LICENSE.
+
+  Contact Information:
+  James P. Ketrenos <ipw2100-admin@linux.intel.com>
+  Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
+
+******************************************************************************/
+#include <linux/compiler.h>
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/if_arp.h>
+#include <linux/in6.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/pci.h>
+#include <linux/proc_fs.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/tcp.h>
+#include <linux/types.h>
+#include <linux/version.h>
+#include <linux/wireless.h>
+#include <linux/etherdevice.h>
+#include <asm/uaccess.h>
+
+#include <net/ieee80211.h>
+
+
+/*
+
+
+802.11 Data Frame
+
+      ,-------------------------------------------------------------------.
+Bytes |  2   |  2   |    6    |    6    |    6    |  2   | 0..2312 |   4  |
+      |------|------|---------|---------|---------|------|---------|------|
+Desc. | ctrl | dura |  DA/RA  |   TA    |    SA   | Sequ |  Frame  |  fcs |
+      |      | tion | (BSSID) |         |         | ence |  data   |      |
+      `--------------------------------------------------|         |------'
+Total: 28 non-data bytes                                 `----.----'
+                                                              |
+       .- 'Frame data' expands to <---------------------------'
+       |
+       V
+      ,---------------------------------------------------.
+Bytes |  1   |  1   |    1    |    3     |  2   |  0-2304 |
+      |------|------|---------|----------|------|---------|
+Desc. | SNAP | SNAP | Control |Eth Tunnel| Type | IP      |
+      | DSAP | SSAP |         |          |      | Packet  |
+      | 0xAA | 0xAA |0x03 (UI)|0x00-00-F8|      |         |
+      `-----------------------------------------|         |
+Total: 8 non-data bytes                         `----.----'
+                                                     |
+       .- 'IP Packet' expands, if WEP enabled, to <--'
+       |
+       V
+      ,-----------------------.
+Bytes |  4  |   0-2296  |  4  |
+      |-----|-----------|-----|
+Desc. | IV  | Encrypted | ICV |
+      |     | IP Packet |     |
+      `-----------------------'
+Total: 8 non-data bytes
+
+
+802.3 Ethernet Data Frame
+
+      ,-----------------------------------------.
+Bytes |   6   |   6   |  2   |  Variable |   4  |
+      |-------|-------|------|-----------|------|
+Desc. | Dest. | Source| Type | IP Packet |  fcs |
+      |  MAC  |  MAC  |      |           |      |
+      `-----------------------------------------'
+Total: 18 non-data bytes
+
+In the event that fragmentation is required, the incoming payload is split into
+N parts of size ieee->fts.  The first fragment contains the SNAP header and the
+remaining packets are just data.
+
+If encryption is enabled, each fragment payload size is reduced by enough space
+to add the prefix and postfix (IV and ICV totalling 8 bytes in the case of WEP)
+So if you have 1500 bytes of payload with ieee->fts set to 500 without
+encryption it will take 3 frames.  With WEP it will take 4 frames as the
+payload of each frame is reduced to 492 bytes.
+
+* SKB visualization
+*
+*  ,- skb->data
+* |
+* |    ETHERNET HEADER        ,-<-- PAYLOAD
+* |                           |     14 bytes from skb->data
+* |  2 bytes for Type --> ,T. |     (sizeof ethhdr)
+* |                       | | |
+* |,-Dest.--. ,--Src.---. | | |
+* |  6 bytes| | 6 bytes | | | |
+* v         | |         | | | |
+* 0         | v       1 | v | v           2
+* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+*     ^     | ^         | ^ |
+*     |     | |         | | |
+*     |     | |         | `T' <---- 2 bytes for Type
+*     |     | |         |
+*     |     | '---SNAP--' <-------- 6 bytes for SNAP
+*     |     |
+*     `-IV--' <-------------------- 4 bytes for IV (WEP)
+*
+*      SNAP HEADER
+*
+*/
+
+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)
+{
+	struct ieee80211_snap_hdr *snap;
+	u8 *oui;
+
+	snap = (struct ieee80211_snap_hdr *)data;
+	snap->dsap = 0xaa;
+	snap->ssap = 0xaa;
+	snap->ctrl = 0x03;
+
+	if (h_proto == 0x8137 || h_proto == 0x80f3)
+		oui = P802_1H_OUI;
+	else
+		oui = RFC1042_OUI;
+	snap->oui[0] = oui[0];
+	snap->oui[1] = oui[1];
+	snap->oui[2] = oui[2];
+
+	*(u16 *)(data + SNAP_SIZE) = htons(h_proto);
+
+	return SNAP_SIZE + sizeof(u16);
+}
+
+static inline int ieee80211_encrypt_fragment(
+	struct ieee80211_device *ieee,
+	struct sk_buff *frag,
+	int hdr_len)
+{
+	struct ieee80211_crypt_data* crypt = ieee->crypt[ieee->tx_keyidx];
+	int res;
+
+#ifdef CONFIG_IEEE80211_CRYPT_TKIP
+	struct ieee80211_hdr *header;
+
+	if (ieee->tkip_countermeasures &&
+	    crypt && crypt->ops && strcmp(crypt->ops->name, "TKIP") == 0) {
+		header = (struct ieee80211_hdr *) frag->data;
+		if (net_ratelimit()) {
+			printk(KERN_DEBUG "%s: TKIP countermeasures: dropped "
+			       "TX packet to " MAC_FMT "\n",
+			       ieee->dev->name, MAC_ARG(header->addr1));
+		}
+		return -1;
+	}
+#endif
+	/* 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)
+		res = crypt->ops->encrypt_mpdu(frag, hdr_len, crypt->priv);
+
+	atomic_dec(&crypt->refcnt);
+	if (res < 0) {
+		printk(KERN_INFO "%s: Encryption failed: len=%d.\n",
+		       ieee->dev->name, frag->len);
+		ieee->ieee_stats.tx_discards++;
+		return -1;
+	}
+
+	return 0;
+}
+
+
+void ieee80211_txb_free(struct ieee80211_txb *txb) {
+	int i;
+	if (unlikely(!txb))
+		return;
+	for (i = 0; i < txb->nr_frags; i++)
+		if (txb->fragments[i])
+			dev_kfree_skb_any(txb->fragments[i]);
+	kfree(txb);
+}
+
+struct ieee80211_txb *ieee80211_alloc_txb(int nr_frags, int txb_size,
+					  int gfp_mask)
+{
+	struct ieee80211_txb *txb;
+	int i;
+	txb = kmalloc(
+		sizeof(struct ieee80211_txb) + (sizeof(u8*) * nr_frags),
+		gfp_mask);
+	if (!txb)
+		return NULL;
+
+	memset(txb, sizeof(struct ieee80211_txb), 0);
+	txb->nr_frags = nr_frags;
+	txb->frag_size = txb_size;
+
+	for (i = 0; i < nr_frags; i++) {
+		txb->fragments[i] = dev_alloc_skb(txb_size);
+		if (unlikely(!txb->fragments[i])) {
+			i--;
+			break;
+		}
+	}
+	if (unlikely(i != nr_frags)) {
+		while (i >= 0)
+			dev_kfree_skb_any(txb->fragments[i--]);
+		kfree(txb);
+		return NULL;
+	}
+	return txb;
+}
+
+/* SKBs are added to the ieee->tx_queue. */
+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 *frag_hdr;
+	int i, bytes_per_frag, nr_frags, bytes_last_frag, frag_size;
+	unsigned long flags;
+	struct net_device_stats *stats = &ieee->stats;
+	int ether_type, encrypt;
+	int bytes, fc, hdr_len;
+	struct sk_buff *skb_frag;
+	struct ieee80211_hdr header = { /* Ensure zero initialized */
+		.duration_id = 0,
+		.seq_ctl = 0
+	};
+	u8 dest[ETH_ALEN], src[ETH_ALEN];
+
+	struct ieee80211_crypt_data* crypt;
+
+	spin_lock_irqsave(&ieee->lock, flags);
+
+	/* If there is no driver handler to take the TXB, dont' bother
+	 * creating it... */
+	if (!ieee->hard_start_xmit) {
+		printk(KERN_WARNING "%s: No xmit handler.\n",
+		       ieee->dev->name);
+		goto success;
+	}
+
+	if (unlikely(skb->len < SNAP_SIZE + sizeof(u16))) {
+		printk(KERN_WARNING "%s: skb too small (%d).\n",
+		       ieee->dev->name, skb->len);
+		goto success;
+	}
+
+	ether_type = ntohs(((struct ethhdr *)skb->data)->h_proto);
+
+	crypt = ieee->crypt[ieee->tx_keyidx];
+
+	encrypt = !(ether_type == ETH_P_PAE && ieee->ieee802_1x) &&
+		ieee->host_encrypt && crypt && crypt->ops;
+
+	if (!encrypt && ieee->ieee802_1x &&
+	    ieee->drop_unencrypted && ether_type != ETH_P_PAE) {
+		stats->tx_dropped++;
+		goto success;
+	}
+
+#ifdef CONFIG_IEEE80211_DEBUG
+	if (crypt && !encrypt && ether_type == ETH_P_PAE) {
+		struct eapol *eap = (struct eapol *)(skb->data +
+			sizeof(struct ethhdr) - SNAP_SIZE - sizeof(u16));
+		IEEE80211_DEBUG_EAP("TX: IEEE 802.11 EAPOL frame: %s\n",
+			eap_get_type(eap->type));
+	}
+#endif
+
+	/* Save source and destination addresses */
+	memcpy(&dest, skb->data, ETH_ALEN);
+	memcpy(&src, skb->data+ETH_ALEN, ETH_ALEN);
+
+	/* Advance the SKB to the start of the payload */
+	skb_pull(skb, sizeof(struct ethhdr));
+
+	/* Determine total amount of storage required for TXB packets */
+	bytes = skb->len + SNAP_SIZE + sizeof(u16);
+
+	if (encrypt)
+		fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA |
+			IEEE80211_FCTL_WEP;
+	else
+		fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
+
+	if (ieee->iw_mode == IW_MODE_INFRA) {
+		fc |= IEEE80211_FCTL_TODS;
+		/* 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 */
+		memcpy(&header.addr1, dest, ETH_ALEN);
+		memcpy(&header.addr2, src, ETH_ALEN);
+		memcpy(&header.addr3, ieee->bssid, ETH_ALEN);
+	}
+	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;
+
+	/* 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 (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;
+
+	/* 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.) */
+	txb = ieee80211_alloc_txb(nr_frags, frag_size, GFP_ATOMIC);
+	if (unlikely(!txb)) {
+		printk(KERN_WARNING "%s: Could not allocate TXB\n",
+		       ieee->dev->name);
+		goto failed;
+	}
+	txb->encrypted = encrypt;
+	txb->payload_size = bytes;
+
+	for (i = 0; i < nr_frags; i++) {
+		skb_frag = txb->fragments[i];
+
+		if (encrypt)
+			skb_reserve(skb_frag, crypt->ops->extra_prefix_len);
+
+		frag_hdr = (struct ieee80211_hdr *)skb_put(skb_frag, hdr_len);
+		memcpy(frag_hdr, &header, hdr_len);
+
+		/* If this is not the last fragment, then add the MOREFRAGS
+		 * bit to the frame control */
+		if (i != nr_frags - 1) {
+			frag_hdr->frame_ctl = cpu_to_le16(
+				fc | IEEE80211_FCTL_MOREFRAGS);
+			bytes = bytes_per_frag;
+		} else {
+			/* The last fragment takes the remaining length */
+			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);
+			bytes -= SNAP_SIZE + sizeof(u16);
+		}
+
+		memcpy(skb_put(skb_frag, bytes), skb->data, bytes);
+
+		/* Advance the SKB... */
+		skb_pull(skb, bytes);
+
+		/* Encryption routine will move the header forward in order
+		 * to insert the IV between the header and the payload */
+		if (encrypt)
+			ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len);
+		if (ieee->config &
+		    (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
+			skb_put(skb_frag, 4);
+	}
+
+
+ success:
+	spin_unlock_irqrestore(&ieee->lock, flags);
+
+	dev_kfree_skb_any(skb);
+
+	if (txb) {
+		if ((*ieee->hard_start_xmit)(txb, dev) == 0) {
+			stats->tx_packets++;
+			stats->tx_bytes += txb->payload_size;
+			return 0;
+		}
+		ieee80211_txb_free(txb);
+	}
+
+	return 0;
+
+ failed:
+	spin_unlock_irqrestore(&ieee->lock, flags);
+	netif_stop_queue(dev);
+	stats->tx_errors++;
+	return 1;
+
+}
+
+EXPORT_SYMBOL(ieee80211_txb_free);