isdn_v110.c

linux-2.6.15.6

	skb_trim(skb, DecodeMatrix(v, v110_buf, len, skb->data));
	kfree(v110_buf);
	if (skb->len)
		return skb;
	else {
		kfree_skb(skb);
		return NULL;
	}
}

/* EncodeMatrix takes input data in buf, len is the bytecount.
   Data is encoded into v110 frames in m. Return value is the number of
   matrix-lines generated.
 */
static int
EncodeMatrix(unsigned char *buf, int len, unsigned char *m, int mlen)
{
	int line = 0;
	int i = 0;
	int mbit = 128;
	int dbit = 1;
	int introducer = 3;
	int ibit[] = {0, 1, 1};

	while ((i < len) && (line < mlen)) {	/* while we still have input data */
		switch (line % 10) {	/* in which line of the matrix are we? */
			case 0:
				m[line++] = 0x00;	/* line 0 is always 0 */
				mbit = 128;	/* go on with the 7th bit */
				break;
			case 5:
				m[line++] = 0xbf;	/* line 5 is always 10111111 */
				mbit = 128;	/* go on with the 7th bit */
				break;
		}
		if (line >= mlen) {
			printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
			return line;
		}
	next_bit:
		switch (mbit) { /* leftmost or rightmost bit ? */
			case 1:
				line++;	/* rightmost -> go to next line */
				if (line >= mlen) {
					printk(KERN_WARNING "isdn_v110 (EncodeMatrix): buffer full!\n");
					return line;
				}
			case 128:
				m[line] = 128;	/* leftmost -> set byte to 1000000 */
				mbit = 64;	/* current bit in the matrix line */
				continue;
		}
		if (introducer) {	/* set 110 sequence ? */
			introducer--;	/* set on digit less */
			m[line] |= ibit[introducer] ? mbit : 0;	/* set corresponding bit */
			mbit >>= 1;	/* bit of matrix line  >> 1 */
			goto next_bit;	/* and go on there */
		}               /* else push data bits into the matrix! */
		m[line] |= (buf[i] & dbit) ? mbit : 0;	/* set data bit in matrix */
		if (dbit == 128) {	/* was it the last one? */
			dbit = 1;	/* then go on with first bit of  */
			i++;            /* next byte in input buffer */
			if (i < len)	/* input buffer done ? */
				introducer = 3;	/* no, write introducer 110 */
			else {  /* input buffer done ! */
				m[line] |= (mbit - 1) & 0xfe;	/* set remaining bits in line to 1 */
				break;
			}
		} else          /* not the last data bit */
			dbit <<= 1;	/* then go to next data bit */
		mbit >>= 1;     /* go to next bit of matrix */
		goto next_bit;

	}
	/* if necessary, generate remaining lines of the matrix... */
	if ((line) && ((line + 10) < mlen))
		switch (++line % 10) {
			case 1:
				m[line++] = 0xfe;
			case 2:
				m[line++] = 0xfe;
			case 3:
				m[line++] = 0xfe;
			case 4:
				m[line++] = 0xfe;
			case 5:
				m[line++] = 0xbf;
			case 6:
				m[line++] = 0xfe;
			case 7:
				m[line++] = 0xfe;
			case 8:
				m[line++] = 0xfe;
			case 9:
				m[line++] = 0xfe;
		}
	return line;            /* that's how many lines we have */
}

/*
 * Build a sync frame.
 */
static struct sk_buff *
isdn_v110_sync(isdn_v110_stream *v)
{
	struct sk_buff *skb;

	if (v == NULL) {
		/* invalid handle, no chance to proceed */
		printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
		return NULL;
	}
	if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
		skb_reserve(skb, v->skbres);
		memcpy(skb_put(skb, v->framelen), v->OfflineFrame, v->framelen);
	}
	return skb;
}

/*
 * Build an idle frame.
 */
static struct sk_buff *
isdn_v110_idle(isdn_v110_stream *v)
{
	struct sk_buff *skb;

	if (v == NULL) {
		/* invalid handle, no chance to proceed */
		printk(KERN_WARNING "isdn_v110_sync called with NULL stream!\n");
		return NULL;
	}
	if ((skb = dev_alloc_skb(v->framelen + v->skbres))) {
		skb_reserve(skb, v->skbres);
		memcpy(skb_put(skb, v->framelen), v->OnlineFrame, v->framelen);
	}
	return skb;
}

struct sk_buff *
isdn_v110_encode(isdn_v110_stream * v, struct sk_buff *skb)
{
	int i;
	int j;
	int rlen;
	int mlen;
	int olen;
	int size;
	int sval1;
	int sval2;
	int nframes;
	unsigned char *v110buf;
	unsigned char *rbuf;
	struct sk_buff *nskb;

	if (v == NULL) {
		/* invalid handle, no chance to proceed */
		printk(KERN_WARNING "isdn_v110_encode called with NULL stream!\n");
		return NULL;
	}
	if (!skb) {
		/* invalid skb, no chance to proceed */
		printk(KERN_WARNING "isdn_v110_encode called with NULL skb!\n");
		return NULL;
	}
	rlen = skb->len;
	nframes = (rlen + 3) / 4;
	v110buf = v->encodebuf;
	if ((nframes * 40) > v->maxsize) {
		size = v->maxsize;
		rlen = v->maxsize / 40;
	} else
		size = nframes * 40;
	if (!(nskb = dev_alloc_skb(size + v->skbres + sizeof(int)))) {
		printk(KERN_WARNING "isdn_v110_encode: Couldn't alloc skb\n");
		return NULL;
	}
	skb_reserve(nskb, v->skbres + sizeof(int));
	if (skb->len == 0) {
		memcpy(skb_put(nskb, v->framelen), v->OnlineFrame, v->framelen);
		*((int *)skb_push(nskb, sizeof(int))) = 0;
		return nskb;
	}
	mlen = EncodeMatrix(skb->data, rlen, v110buf, size);
	/* now distribute 2 or 4 bits each to the output stream! */
	rbuf = skb_put(nskb, size);
	olen = 0;
	sval1 = 8 - v->nbits;
	sval2 = v->key << sval1;
	for (i = 0; i < mlen; i++) {
		v110buf[i] = FlipBits(v110buf[i], v->nbits);
		for (j = 0; j < v->nbytes; j++) {
			if (size--)
				*rbuf++ = ~v->key | (((v110buf[i] << (j * v->nbits)) & sval2) >> sval1);
			else {
				printk(KERN_WARNING "isdn_v110_encode: buffers full!\n");
				goto buffer_full;
			}
			olen++;
		}
	}
buffer_full:
	skb_trim(nskb, olen);
	*((int *)skb_push(nskb, sizeof(int))) = rlen;
	return nskb;
}

int
isdn_v110_stat_callback(int idx, isdn_ctrl *c)
{
	isdn_v110_stream *v = NULL;
	int i;
	int ret = 0;

	if (idx < 0)
		return 0;
	switch (c->command) {
		case ISDN_STAT_BSENT:
                        /* Keep the send-queue of the driver filled
			 * with frames:
			 * If number of outstanding frames < 3,
			 * send down an Idle-Frame (or an Sync-Frame, if
			 * v->SyncInit != 0). 
			 */
			if (!(v = dev->v110[idx]))
				return 0;
			atomic_inc(&dev->v110use[idx]);
			for (i=0; i * v->framelen < c->parm.length; i++) {
				if (v->skbidle > 0) {
					v->skbidle--;
					ret = 1;
				} else {
					if (v->skbuser > 0)
						v->skbuser--;
					ret = 0;
				}
			}
			for (i = v->skbuser + v->skbidle; i < 2; i++) {
				struct sk_buff *skb;
				if (v->SyncInit > 0)
					skb = isdn_v110_sync(v);
				else
					skb = isdn_v110_idle(v);
				if (skb) {
					if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
						dev_kfree_skb(skb);
						break;
					} else {
						if (v->SyncInit)
							v->SyncInit--;
						v->skbidle++;
					}
				} else
					break;
			}
			atomic_dec(&dev->v110use[idx]);
			return ret;
		case ISDN_STAT_DHUP:
		case ISDN_STAT_BHUP:
			while (1) {
				atomic_inc(&dev->v110use[idx]);
				if (atomic_dec_and_test(&dev->v110use[idx])) {
					isdn_v110_close(dev->v110[idx]);
					dev->v110[idx] = NULL;
					break;
				}
				mdelay(1);
			}
			break;
		case ISDN_STAT_BCONN:
			if (dev->v110emu[idx] && (dev->v110[idx] == NULL)) {
				int hdrlen = dev->drv[c->driver]->interface->hl_hdrlen;
				int maxsize = dev->drv[c->driver]->interface->maxbufsize;
				atomic_inc(&dev->v110use[idx]);
				switch (dev->v110emu[idx]) {
					case ISDN_PROTO_L2_V11096:
						dev->v110[idx] = isdn_v110_open(V110_9600, hdrlen, maxsize);
						break;
					case ISDN_PROTO_L2_V11019:
						dev->v110[idx] = isdn_v110_open(V110_19200, hdrlen, maxsize);
						break;
					case ISDN_PROTO_L2_V11038:
						dev->v110[idx] = isdn_v110_open(V110_38400, hdrlen, maxsize);
						break;
					default:;
				}
				if ((v = dev->v110[idx])) {
					while (v->SyncInit) {
						struct sk_buff *skb = isdn_v110_sync(v);
						if (dev->drv[c->driver]->interface->writebuf_skb(c->driver, c->arg, 1, skb) <= 0) {
							dev_kfree_skb(skb);
							/* Unable to send, try later */
							break;
						}
						v->SyncInit--;
						v->skbidle++;
					}
				} else
					printk(KERN_WARNING "isdn_v110: Couldn't open stream for chan %d\n", idx);
				atomic_dec(&dev->v110use[idx]);
			}
			break;
		default:
			return 0;
	}
	return 0;
}