ieee80211_tx.c

RTL8187 for linux驱动 提供内核支持802.11g的模块

/******************************************************************************
  
  Copyright(c) 2003 - 2004 Intel Corporation. All rights reserved.
  
  ieee802.11 header construcion, some TX logic and misc modifications
  for rtl8180-sa2400 driver added by Andrea Merello <[e-mail]>
  
  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 <[e-mail]>
  Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  
  Please note that the file has been heavily modified for the rtl8180-sa2400
  driver, so please don't contact the above person for bugs or other issues
  if you are not sure they are related to the original code

******************************************************************************/
#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 "ieee80211.h"
/*
#define DEBUG_SKB2TXB
#define DEBUG_HARD_XMIT
*/

/*

802.11 frame_contorl for data frames - 2 bytes
     ,-----------------------------------------------------------------------------------------.
bits | 0  |  1  |  2  |  3  |  4  |  5  |  6  |  7  |  8  |  9  |  a  |  b  |  c  |  d  |  e   |
     |----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|------|
val  | 0  |  0  |  0  |  1  |  x  |  0  |  0  |  0  |  1  |  0  |  x  |  x  |  x  |  x  |  x   |
     |----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|-----|------|
desc | ^-ver-^  |  ^type-^  |  ^-----subtype-----^  | to  |from |more |retry| pwr |more |wep   |
     |          |           | x=0 data,x=1 data+ack | DS  | DS  |frag |     | mgm |data |      |
     '-----------------------------------------------------------------------------------------'
		                                    /\
                                                    |
802.11 Data Frame                                   |
           ,--------- 'ctrl' expands to >-----------'
          |
      ,---'--,
      |      |------------------------------------------------------------.
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 ieee_802_11_snap_header *snap;
	u8 *oui;

	snap = (struct ieee_802_11_snap_header *)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);
}

#ifndef CONFIG_IEEE80211_NOWEP
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 NOT_YET
	if (ieee->tkip_countermeasures &&
	    crypt && crypt->ops && strcmp(crypt->ops->name, "TKIP") == 0) {
		hdr = (struct ieee80211_hdr *) skb->data;
		if (net_ratelimit()) {
			printk(KERN_DEBUG "%s: TKIP countermeasures: dropped "
			       "TX packet to " MACSTR "\n",
			       ieee->dev->name, MAC2STR(hdr->addr1));
		}
		return NULL;
	}
#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;
}
#endif

void ieee80211_r8180_txb_free(struct ieee80211_txb *txb) {
	int i;
	//static int alloc=0;
	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_r8180_alloc_txb(int nr_frags, int txb_size,
					  int gfp_mask) {
	struct ieee80211_txb *txb;
	int i;
	//static int dealloc=0;
	txb = (struct ieee80211_txb *)kmalloc(
		sizeof(struct ieee80211_txb) + (sizeof(u8*) * nr_frags), 
		gfp_mask);
	if (!txb)
		return NULL;

	memset(txb, 0, sizeof(struct ieee80211_txb));
	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);
		IEEE80211DMESG("fail");
		return NULL;
	}
	
	return txb;
}


u16 ieee80211_calc_duration(u32 len, short rate)//,short* ext)
{
	//*ext=0;
	u16 duration;
	u16 drift;
	switch(rate){
	case 0://1mbps
	//	*ext=0;
		duration = ((len+4)<<4) /0x2;
		drift = ((len+4)<<4) % 0x2;
		if(drift ==0 ) break;
		duration++;
		break;
		
	case 1://2mbps
	//	*ext=0;
		duration = ((len+4)<<4) /0x4;
		drift = ((len+4)<<4) % 0x4;
		if(drift ==0 ) break;
		duration++;
		break;
		
	case 2: //5.5mbps
	//	*ext=0;
		duration = ((len+4)<<4) /0xb;
		drift = ((len+4)<<4) % 0xb;
		if(drift ==0 ) 
			break;
		duration++;
		break;
		
	default:
	case 3://11mbps				
	//	*ext=0;
		duration = ((len+4)<<4) /0x16;
		drift = ((len+4)<<4) % 0x16;
		if(drift ==0 ) 
			break;
		duration++;
	/*	if(drift > 6) 
			break;
		*ext=1;*/
		break;
	}
	
	return duration;
}



struct ieee80211_txb *ieee80211_r8180_skb_to_txb(struct ieee80211_device *ieee, 
					   struct sk_buff *skb)
{
	struct ieee80211_txb *txb;
	int i, payload_size, nr_frags, last_payload_size;
	//unsigned long flags;
	struct net_device_stats *stats = &ieee->stats;
	int ether_type, encrypt;
	int size, fc, hdr_len;
	struct sk_buff *skb_frag;
	struct ieee80211_header_data *header;
	u8 src_addr[ETH_ALEN];
	u8 dst_addr[ETH_ALEN];
	u16 acktime;
	u8 icv[]={0,0,0,0};
	
#ifndef CONFIG_IEEE80211_NOWEP
	struct ieee80211_crypt_data* crypt;
#endif
	/* we don't aquire lock since this is called only from 
	 * already-locked context
	 */	
	
	//spin_lock_irqsave(&ieee->lock, flags);
	
	
	/* We do not return fail even if not associated,
	 * during reassociation data frame are accepted until
	 * the TX buffer is full. The nic should avoid to TX
	 * them due to HW disable of the dma from data ring