hdlcdrv.c

linux-2.4.29操作系统的源码

/*****************************************************************************/

/*
 *	hdlcdrv.c  -- HDLC packet radio network driver.
 *
 *	Copyright (C) 1996-2000  Thomas Sailer ([e-mail])
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  Please note that the GPL allows you to use the driver, NOT the radio.
 *  In order to use the radio, you need a license from the communications
 *  authority of your country.
 *
 *  The driver was derived from Donald Beckers skeleton.c
 *	Written 1993-94 by Donald Becker.
 *
 *  History:
 *   0.1  21.09.1996  Started
 *        18.10.1996  Changed to new user space access routines 
 *                    (copy_{to,from}_user)
 *   0.2  21.11.1996  various small changes
 *   0.3  03.03.1997  fixed (hopefully) IP not working with ax.25 as a module
 *   0.4  16.04.1997  init code/data tagged
 *   0.5  30.07.1997  made HDLC buffers bigger (solves a problem with the
 *                    soundmodem driver)
 *   0.6  05.04.1998  add spinlocks
 *   0.7  03.08.1999  removed some old compatibility cruft
 *   0.8  12.02.2000  adapted to softnet driver interface
 */

/*****************************************************************************/

#include <linux/config.h>
#include <linux/version.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/if.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>

#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/hdlcdrv.h>
/* prototypes for ax25_encapsulate and ax25_rebuild_header */
#include <net/ax25.h> 

/* make genksyms happy */
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/tcp.h>

/* --------------------------------------------------------------------- */

/*
 * The name of the card. Is used for messages and in the requests for
 * io regions, irqs and dma channels
 */

static char ax25_bcast[AX25_ADDR_LEN] =
{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '0' << 1};
static char ax25_nocall[AX25_ADDR_LEN] =
{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};

/* --------------------------------------------------------------------- */

#define KISS_VERBOSE

/* --------------------------------------------------------------------- */

#define PARAM_TXDELAY   1
#define PARAM_PERSIST   2
#define PARAM_SLOTTIME  3
#define PARAM_TXTAIL    4
#define PARAM_FULLDUP   5
#define PARAM_HARDWARE  6
#define PARAM_RETURN    255

/* --------------------------------------------------------------------- */
/*
 * the CRC routines are stolen from WAMPES
 * by Dieter Deyke
 */

static const unsigned short crc_ccitt_table[] = {
	0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
	0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
	0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
	0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
	0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
	0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
	0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
	0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
	0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
	0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
	0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
	0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
	0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
	0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
	0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
	0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
	0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
	0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
	0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
	0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
	0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
	0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
	0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
	0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
	0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
	0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
	0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
	0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
	0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
	0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
	0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
	0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};

/*---------------------------------------------------------------------------*/

static inline void append_crc_ccitt(unsigned char *buffer, int len)
{
 	unsigned int crc = 0xffff;

	for (;len>0;len--)
		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buffer++) & 0xff];
	crc ^= 0xffff;
	*buffer++ = crc;
	*buffer++ = crc >> 8;
}

/*---------------------------------------------------------------------------*/

static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
{
	unsigned int crc = 0xffff;

	for (; cnt > 0; cnt--)
		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
	return (crc & 0xffff) == 0xf0b8;
}

/*---------------------------------------------------------------------------*/

#if 0
static int calc_crc_ccitt(const unsigned char *buf, int cnt)
{
	unsigned int crc = 0xffff;

	for (; cnt > 0; cnt--)
		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
	crc ^= 0xffff;
	return (crc & 0xffff);
}
#endif

/* ---------------------------------------------------------------------- */

#define tenms_to_2flags(s,tenms) ((tenms * s->par.bitrate) / 100 / 16)

/* ---------------------------------------------------------------------- */
/*
 * The HDLC routines
 */

static int hdlc_rx_add_bytes(struct hdlcdrv_state *s, unsigned int bits, 
			     int num)
{
	int added = 0;
	
	while (s->hdlcrx.rx_state && num >= 8) {
		if (s->hdlcrx.len >= sizeof(s->hdlcrx.buffer)) {
			s->hdlcrx.rx_state = 0;
			return 0;
		}
		*s->hdlcrx.bp++ = bits >> (32-num);
		s->hdlcrx.len++;
		num -= 8;
		added += 8;
	}
	return added;
}

static void hdlc_rx_flag(struct net_device *dev, struct hdlcdrv_state *s)
{
	struct sk_buff *skb;
	int pkt_len;
	unsigned char *cp;

	if (s->hdlcrx.len < 4) 
		return;
	if (!check_crc_ccitt(s->hdlcrx.buffer, s->hdlcrx.len)) 
		return;
	pkt_len = s->hdlcrx.len - 2 + 1; /* KISS kludge */
	if (!(skb = dev_alloc_skb(pkt_len))) {
		printk("%s: memory squeeze, dropping packet\n", dev->name);
		s->stats.rx_dropped++;
		return;
	}
	skb->dev = dev;
	cp = skb_put(skb, pkt_len);
	*cp++ = 0; /* KISS kludge */
	memcpy(cp, s->hdlcrx.buffer, pkt_len - 1);
	skb->protocol = htons(ETH_P_AX25);
	skb->mac.raw = skb->data;
	netif_rx(skb);
	s->stats.rx_packets++;
}

void hdlcdrv_receiver(struct net_device *dev, struct hdlcdrv_state *s)
{
	int i;
	unsigned int mask1, mask2, mask3, mask4, mask5, mask6, word;
	
	if (!s || s->magic != HDLCDRV_MAGIC) 
		return;
	if (test_and_set_bit(0, &s->hdlcrx.in_hdlc_rx))
		return;

	while (!hdlcdrv_hbuf_empty(&s->hdlcrx.hbuf)) {
		word = hdlcdrv_hbuf_get(&s->hdlcrx.hbuf);	

#ifdef HDLCDRV_DEBUG
		hdlcdrv_add_bitbuffer_word(&s->bitbuf_hdlc, word);
#endif /* HDLCDRV_DEBUG */
	       	s->hdlcrx.bitstream >>= 16;
		s->hdlcrx.bitstream |= word << 16;
		s->hdlcrx.bitbuf >>= 16;
		s->hdlcrx.bitbuf |= word << 16;
		s->hdlcrx.numbits += 16;
		for(i = 15, mask1 = 0x1fc00, mask2 = 0x1fe00, mask3 = 0x0fc00,
		    mask4 = 0x1f800, mask5 = 0xf800, mask6 = 0xffff; 
		    i >= 0; 
		    i--, mask1 <<= 1, mask2 <<= 1, mask3 <<= 1, mask4 <<= 1, 
		    mask5 <<= 1, mask6 = (mask6 << 1) | 1) {
			if ((s->hdlcrx.bitstream & mask1) == mask1)
				s->hdlcrx.rx_state = 0; /* abort received */
			else if ((s->hdlcrx.bitstream & mask2) == mask3) {
				/* flag received */
				if (s->hdlcrx.rx_state) {
					hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf 
							  << (8+i),
							  s->hdlcrx.numbits
							  -8-i);
					hdlc_rx_flag(dev, s);
				}
				s->hdlcrx.len = 0;
				s->hdlcrx.bp = s->hdlcrx.buffer;
				s->hdlcrx.rx_state = 1;
				s->hdlcrx.numbits = i;
			} else if ((s->hdlcrx.bitstream & mask4) == mask5) {
				/* stuffed bit */
				s->hdlcrx.numbits--;
				s->hdlcrx.bitbuf = (s->hdlcrx.bitbuf & (~mask6)) |
					((s->hdlcrx.bitbuf & mask6) << 1);
			}
		}
		s->hdlcrx.numbits -= hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf,
						       s->hdlcrx.numbits);
	}
	clear_bit(0, &s->hdlcrx.in_hdlc_rx);
}

/* ---------------------------------------------------------------------- */

static inline void do_kiss_params(struct hdlcdrv_state *s,
				  unsigned char *data, unsigned long len)
{

#ifdef KISS_VERBOSE
#define PKP(a,b) printk(KERN_INFO "hdlcdrv.c: channel params: " a "\n", b)
#else /* KISS_VERBOSE */	      
#define PKP(a,b) 
#endif /* KISS_VERBOSE */	      

	if (len < 2)
		return;
	switch(data[0]) {
	case PARAM_TXDELAY:
		s->ch_params.tx_delay = data[1];
		PKP("TX delay = %ums", 10 * s->ch_params.tx_delay);
		break;
	case PARAM_PERSIST:   
		s->ch_params.ppersist = data[1];
		PKP("p persistence = %u", s->ch_params.ppersist);
		break;
	case PARAM_SLOTTIME:  
		s->ch_params.slottime = data[1];
		PKP("slot time = %ums", s->ch_params.slottime);
		break;
	case PARAM_TXTAIL:    
		s->ch_params.tx_tail = data[1];
		PKP("TX tail = %ums", s->ch_params.tx_tail);
		break;
	case PARAM_FULLDUP:   
		s->ch_params.fulldup = !!data[1];
		PKP("%s duplex", s->ch_params.fulldup ? "full" : "half");
		break;
	default:
		break;
	}
#undef PKP
}

/* ---------------------------------------------------------------------- */

void hdlcdrv_transmitter(struct net_device *dev, struct hdlcdrv_state *s)
{
	unsigned int mask1, mask2, mask3;
	int i;
	struct sk_buff *skb;
	int pkt_len;

	if (!s || s->magic != HDLCDRV_MAGIC) 
		return;
	if (test_and_set_bit(0, &s->hdlctx.in_hdlc_tx))
		return;
	for (;;) {
		if (s->hdlctx.numbits >= 16) {
			if (hdlcdrv_hbuf_full(&s->hdlctx.hbuf)) {
				clear_bit(0, &s->hdlctx.in_hdlc_tx);
				return;
			}
			hdlcdrv_hbuf_put(&s->hdlctx.hbuf, s->hdlctx.bitbuf);
			s->hdlctx.bitbuf >>= 16;
			s->hdlctx.numbits -= 16;
		}
		switch (s->hdlctx.tx_state) {
		default:
			clear_bit(0, &s->hdlctx.in_hdlc_tx);
			return;
		case 0:
		case 1:
			if (s->hdlctx.numflags) {
				s->hdlctx.numflags--;
				s->hdlctx.bitbuf |= 
					0x7e7e << s->hdlctx.numbits;
				s->hdlctx.numbits += 16;
				break;
			}
			if (s->hdlctx.tx_state == 1) {
				clear_bit(0, &s->hdlctx.in_hdlc_tx);
				return;
			}
			if (!(skb = s->skb)) {
				int flgs = tenms_to_2flags(s, s->ch_params.tx_tail);
				if (flgs < 2)
					flgs = 2;
				s->hdlctx.tx_state = 1;
				s->hdlctx.numflags = flgs;
				break;
			}
			s->skb = NULL;
			netif_wake_queue(dev);
			pkt_len = skb->len-1; /* strip KISS byte */
			if (pkt_len >= HDLCDRV_MAXFLEN || pkt_len < 2) {
				s->hdlctx.tx_state = 0;
				s->hdlctx.numflags = 1;
				dev_kfree_skb_irq(skb);
				break;
			}
			memcpy(s->hdlctx.buffer, skb->data+1, pkt_len);
			dev_kfree_skb_irq(skb);
			s->hdlctx.bp = s->hdlctx.buffer;
			append_crc_ccitt(s->hdlctx.buffer, pkt_len);
			s->hdlctx.len = pkt_len+2; /* the appended CRC */
			s->hdlctx.tx_state = 2;
			s->hdlctx.bitstream = 0;
			s->stats.tx_packets++;
			break;
		case 2:
			if (!s->hdlctx.len) {
				s->hdlctx.tx_state = 0;
				s->hdlctx.numflags = 1;
				break;
			}
			s->hdlctx.len--;
			s->hdlctx.bitbuf |= *s->hdlctx.bp <<
				s->hdlctx.numbits;
			s->hdlctx.bitstream >>= 8;
			s->hdlctx.bitstream |= (*s->hdlctx.bp++) << 16;
			mask1 = 0x1f000;
			mask2 = 0x10000;
			mask3 = 0xffffffff >> (31-s->hdlctx.numbits);
			s->hdlctx.numbits += 8;
			for(i = 0; i < 8; i++, mask1 <<= 1, mask2 <<= 1, 
			    mask3 = (mask3 << 1) | 1) {
				if ((s->hdlctx.bitstream & mask1) != mask1) 
					continue;
				s->hdlctx.bitstream &= ~mask2;
				s->hdlctx.bitbuf = 
					(s->hdlctx.bitbuf & mask3) |
						((s->hdlctx.bitbuf & 
						 (~mask3)) << 1);
				s->hdlctx.numbits++;
				mask3 = (mask3 << 1) | 1;
			}
			break;
		}
	}
}

/* ---------------------------------------------------------------------- */

static void start_tx(struct net_device *dev, struct hdlcdrv_state *s)
{
	s->hdlctx.tx_state = 0;
	s->hdlctx.numflags = tenms_to_2flags(s, s->ch_params.tx_delay);
	s->hdlctx.bitbuf = s->hdlctx.bitstream = s->hdlctx.numbits = 0;
	hdlcdrv_transmitter(dev, s);
	s->hdlctx.ptt = 1;
	s->ptt_keyed++;
}

/* ---------------------------------------------------------------------- */

static unsigned short random_seed;

static inline unsigned short random_num(void)
{
	random_seed = 28629 * random_seed + 157;
	return random_seed;
}

/* ---------------------------------------------------------------------- */

void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
{
	if (!s || s->magic != HDLCDRV_MAGIC || s->hdlctx.ptt || !s->skb) 
		return;
	if (s->ch_params.fulldup) {
		start_tx(dev, s);
		return;
	}
	if (s->hdlcrx.dcd) {
		s->hdlctx.slotcnt = s->ch_params.slottime;