capi.c

讲述linux的初始化过程

				capifs_free_ncci(0, mp->minor);
#endif
				if (mp->tty) {
					mp->nccip = 0;
#ifdef _DEBUG_REFCOUNT
					printk(KERN_DEBUG "reset mp->nccip\n");
#endif
					tty_hangup(mp->tty);
				} else if (mp->file) {
					mp->nccip = 0;
#ifdef _DEBUG_REFCOUNT
					printk(KERN_DEBUG "reset mp->nccip\n");
#endif
					wake_up_interruptible(&mp->recvwait);
					wake_up_interruptible(&mp->sendwait);
				} else {
					capiminor_free(mp);
				}
			}
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
			kmem_cache_free(capincci_cachep, np);
			if (*pp == 0) return;
		} else {
			pp = &(*pp)->next;
		}
	}
}

struct capincci *capincci_find(struct capidev *cdev, __u32 ncci)
{
	struct capincci *p;

	for (p=cdev->nccis; p ; p = p->next) {
		if (p->ncci == ncci)
			break;
	}
	return p;
}

/* -------- struct capidev ------------------------------------------ */

static struct capidev *capidev_alloc(struct file *file)
{
	struct capidev *cdev;
	struct capidev **pp;

	cdev = (struct capidev *)kmem_cache_alloc(capidev_cachep, GFP_KERNEL);
	if (!cdev)
		return 0;
	memset(cdev, 0, sizeof(struct capidev));
	cdev->file = file;
	cdev->minor = MINOR(file->f_dentry->d_inode->i_rdev);

	skb_queue_head_init(&cdev->recvqueue);
	init_waitqueue_head(&cdev->recvwait);
	pp=&capidev_openlist;
	while (*pp) pp = &(*pp)->next;
	*pp = cdev;
        return cdev;
}

static void capidev_free(struct capidev *cdev)
{
	struct capidev **pp;
	struct sk_buff *skb;

	if (cdev->applid)
		(*capifuncs->capi_release) (cdev->applid);
	cdev->applid = 0;

	while ((skb = skb_dequeue(&cdev->recvqueue)) != 0) {
		kfree_skb(skb);
	}
	
	pp=&capidev_openlist;
	while (*pp && *pp != cdev) pp = &(*pp)->next;
	if (*pp)
		*pp = cdev->next;

	kmem_cache_free(capidev_cachep, cdev);
}

static struct capidev *capidev_find(__u16 applid)
{
	struct capidev *p;
	for (p=capidev_openlist; p; p = p->next) {
		if (p->applid == applid)
			break;
	}
	return p;
}

#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
/* -------- handle data queue --------------------------------------- */

struct sk_buff *
gen_data_b3_resp_for(struct capiminor *mp, struct sk_buff *skb)
{
	struct sk_buff *nskb;
	nskb = alloc_skb(CAPI_DATA_B3_RESP_LEN, GFP_ATOMIC);
	if (nskb) {
		__u16 datahandle = CAPIMSG_U16(skb->data,CAPIMSG_BASELEN+4+4+2);
		unsigned char *s = skb_put(nskb, CAPI_DATA_B3_RESP_LEN);
		capimsg_setu16(s, 0, CAPI_DATA_B3_RESP_LEN);
		capimsg_setu16(s, 2, mp->applid);
		capimsg_setu8 (s, 4, CAPI_DATA_B3);
		capimsg_setu8 (s, 5, CAPI_RESP);
		capimsg_setu16(s, 6, mp->msgid++);
		capimsg_setu32(s, 8, mp->ncci);
		capimsg_setu16(s, 12, datahandle);
	}
	return nskb;
}

int handle_recv_skb(struct capiminor *mp, struct sk_buff *skb)
{
	struct sk_buff *nskb;
	unsigned int datalen;
	__u16 errcode, datahandle;

	datalen = skb->len - CAPIMSG_LEN(skb->data);
	if (mp->tty) {
		if (mp->tty->ldisc.receive_buf == 0) {
			printk(KERN_ERR "capi: ldisc has no receive_buf function\n");
			return -1;
		}
		if (mp->ttyinstop) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
			printk(KERN_DEBUG "capi: recv tty throttled\n");
#endif
			return -1;
		}
		if (mp->tty->ldisc.receive_room &&
		    mp->tty->ldisc.receive_room(mp->tty) < datalen) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
			printk(KERN_DEBUG "capi: no room in tty\n");
#endif
			return -1;
		}
		if ((nskb = gen_data_b3_resp_for(mp, skb)) == 0) {
			printk(KERN_ERR "capi: gen_data_b3_resp failed\n");
			return -1;
		}
		datahandle = CAPIMSG_U16(skb->data,CAPIMSG_BASELEN+4);
		errcode = (*capifuncs->capi_put_message)(mp->applid, nskb);
		if (errcode != CAPI_NOERROR) {
			printk(KERN_ERR "capi: send DATA_B3_RESP failed=%x\n",
					errcode);
			kfree_skb(nskb);
			return -1;
		}
		(void)skb_pull(skb, CAPIMSG_LEN(skb->data));
#ifdef _DEBUG_DATAFLOW
		printk(KERN_DEBUG "capi: DATA_B3_RESP %u len=%d => ldisc\n",
					datahandle, skb->len);
#endif
		mp->tty->ldisc.receive_buf(mp->tty, skb->data, 0, skb->len);
		kfree_skb(skb);
		return 0;

	} else if (mp->file) {
		if (skb_queue_len(&mp->recvqueue) > CAPINC_MAX_RECVQUEUE) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
			printk(KERN_DEBUG "capi: no room in raw queue\n");
#endif
			return -1;
		}
		if ((nskb = gen_data_b3_resp_for(mp, skb)) == 0) {
			printk(KERN_ERR "capi: gen_data_b3_resp failed\n");
			return -1;
		}
		datahandle = CAPIMSG_U16(skb->data,CAPIMSG_BASELEN+4);
		errcode = (*capifuncs->capi_put_message)(mp->applid, nskb);
		if (errcode != CAPI_NOERROR) {
			printk(KERN_ERR "capi: send DATA_B3_RESP failed=%x\n",
					errcode);
			kfree_skb(nskb);
			return -1;
		}
		(void)skb_pull(skb, CAPIMSG_LEN(skb->data));
#ifdef _DEBUG_DATAFLOW
		printk(KERN_DEBUG "capi: DATA_B3_RESP %u len=%d => raw\n",
					datahandle, skb->len);
#endif
		skb_queue_tail(&mp->recvqueue, skb);
		wake_up_interruptible(&mp->recvwait);
		return 0;
	}
#ifdef _DEBUG_DATAFLOW
	printk(KERN_DEBUG "capi: currently no receiver\n");
#endif
	return -1;
}

void handle_minor_recv(struct capiminor *mp)
{
	struct sk_buff *skb;
	while ((skb = skb_dequeue(&mp->inqueue)) != 0) {
		unsigned int len = skb->len;
		mp->inbytes -= len;
		if (handle_recv_skb(mp, skb) < 0) {
			skb_queue_head(&mp->inqueue, skb);
			mp->inbytes += len;
			return;
		}
	}
}

int handle_minor_send(struct capiminor *mp)
{
	struct sk_buff *skb;
	__u16 len;
	int count = 0;
	__u16 errcode;
	__u16 datahandle;

	if (mp->tty && mp->ttyoutstop) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
		printk(KERN_DEBUG "capi: send: tty stopped\n");
#endif
		return 0;
	}

	while ((skb = skb_dequeue(&mp->outqueue)) != 0) {
		datahandle = mp->datahandle;
		len = (__u16)skb->len;
		skb_push(skb, CAPI_DATA_B3_REQ_LEN);
		memset(skb->data, 0, CAPI_DATA_B3_REQ_LEN);
		capimsg_setu16(skb->data, 0, CAPI_DATA_B3_REQ_LEN);
		capimsg_setu16(skb->data, 2, mp->applid);
		capimsg_setu8 (skb->data, 4, CAPI_DATA_B3);
		capimsg_setu8 (skb->data, 5, CAPI_REQ);
		capimsg_setu16(skb->data, 6, mp->msgid++);
		capimsg_setu32(skb->data, 8, mp->ncci);	/* NCCI */
		capimsg_setu32(skb->data, 12, (__u32) skb->data); /* Data32 */
		capimsg_setu16(skb->data, 16, len);	/* Data length */
		capimsg_setu16(skb->data, 18, datahandle);
		capimsg_setu16(skb->data, 20, 0);	/* Flags */

		if (capincci_add_ack(mp, datahandle) < 0) {
			skb_pull(skb, CAPI_DATA_B3_REQ_LEN);
			skb_queue_head(&mp->outqueue, skb);
			return count;
		}
		errcode = (*capifuncs->capi_put_message) (mp->applid, skb);
		if (errcode == CAPI_NOERROR) {
			mp->datahandle++;
			count++;
			mp->outbytes -= len;
#ifdef _DEBUG_DATAFLOW
			printk(KERN_DEBUG "capi: DATA_B3_REQ %u len=%u\n",
							datahandle, len);
#endif
			continue;
		}
		capiminor_del_ack(mp, datahandle);

		if (errcode == CAPI_SENDQUEUEFULL) {
			skb_pull(skb, CAPI_DATA_B3_REQ_LEN);
			skb_queue_head(&mp->outqueue, skb);
			break;
		}

		/* ups, drop packet */
		printk(KERN_ERR "capi: put_message = %x\n", errcode);
		mp->outbytes -= len;
		kfree_skb(skb);
	}
	if (count)
		wake_up_interruptible(&mp->sendwait);
	return count;
}

#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
/* -------- function called by lower level -------------------------- */

static void capi_signal(__u16 applid, void *param)
{
	struct capidev *cdev = (struct capidev *)param;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
	struct capiminor *mp;
	__u16 datahandle;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
	struct capincci *np;
	struct sk_buff *skb = 0;
	__u32 ncci;

	(void) (*capifuncs->capi_get_message) (applid, &skb);
	if (!skb) {
		printk(KERN_ERR "BUG: capi_signal: no skb\n");
		return;
	}

	if (CAPIMSG_COMMAND(skb->data) != CAPI_DATA_B3) {
		skb_queue_tail(&cdev->recvqueue, skb);
		wake_up_interruptible(&cdev->recvwait);
		return;
	}
	ncci = CAPIMSG_CONTROL(skb->data);
	for (np = cdev->nccis; np && np->ncci != ncci; np = np->next)
		;
	if (!np) {
		printk(KERN_ERR "BUG: capi_signal: ncci not found\n");
		skb_queue_tail(&cdev->recvqueue, skb);
		wake_up_interruptible(&cdev->recvwait);
		return;
	}
#ifndef CONFIG_ISDN_CAPI_MIDDLEWARE
	skb_queue_tail(&cdev->recvqueue, skb);
	wake_up_interruptible(&cdev->recvwait);
#else /* CONFIG_ISDN_CAPI_MIDDLEWARE */
	mp = np->minorp;
	if (!mp) {
		skb_queue_tail(&cdev->recvqueue, skb);
		wake_up_interruptible(&cdev->recvwait);
		return;
	}


	if (CAPIMSG_SUBCOMMAND(skb->data) == CAPI_IND) {
		datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN+4+4+2);
#ifdef _DEBUG_DATAFLOW
		printk(KERN_DEBUG "capi_signal: DATA_B3_IND %u len=%d\n",
				datahandle, skb->len-CAPIMSG_LEN(skb->data));
#endif
		skb_queue_tail(&mp->inqueue, skb);
		mp->inbytes += skb->len;
		handle_minor_recv(mp);

	} else if (CAPIMSG_SUBCOMMAND(skb->data) == CAPI_CONF) {

		datahandle = CAPIMSG_U16(skb->data, CAPIMSG_BASELEN+4);
#ifdef _DEBUG_DATAFLOW
		printk(KERN_DEBUG "capi_signal: DATA_B3_CONF %u 0x%x\n",
				datahandle,
				CAPIMSG_U16(skb->data, CAPIMSG_BASELEN+4+2));
#endif
		kfree_skb(skb);
		(void)capiminor_del_ack(mp, datahandle);
		if (mp->tty) {
			if (mp->tty->ldisc.write_wakeup)
				mp->tty->ldisc.write_wakeup(mp->tty);
		} else {
			wake_up_interruptible(&mp->sendwait);
		}
		(void)handle_minor_send(mp);

	} else {
		/* ups, let capi application handle it :-) */
		skb_queue_tail(&cdev->recvqueue, skb);
		wake_up_interruptible(&cdev->recvwait);
	}
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
}

/* -------- file_operations for capidev ----------------------------- */

static loff_t
capi_llseek(struct file *file, loff_t offset, int origin)
{
	return -ESPIPE;
}

static ssize_t
capi_read(struct file *file, char *buf, size_t count, loff_t *ppos)
{
	struct capidev *cdev = (struct capidev *)file->private_data;
	struct sk_buff *skb;
	int retval;
	size_t copied;

	if (ppos != &file->f_pos)
		return -ESPIPE;

	if (!cdev->applid)
		return -ENODEV;

	if ((skb = skb_dequeue(&cdev->recvqueue)) == 0) {

		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;

		for (;;) {
			interruptible_sleep_on(&cdev->recvwait);
			if ((skb = skb_dequeue(&cdev->recvqueue)) != 0)
				break;
			if (signal_pending(current))
				break;
		}
		if (skb == 0)
			return -ERESTARTNOHAND;
	}
	if (skb->len > count) {
		skb_queue_head(&cdev->recvqueue, skb);
		return -EMSGSIZE;
	}
	retval = copy_to_user(buf, skb->data, skb->len);
	if (retval) {
		skb_queue_head(&cdev->recvqueue, skb);
		return retval;
	}
	copied = skb->len;

	if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_IND) {
		cdev->nrecvdatapkt++;
	} else {
		cdev->nrecvctlpkt++;
	}

	kfree_skb(skb);

	return copied;
}

static ssize_t
capi_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
	struct capidev *cdev = (struct capidev *)file->private_data;
	struct sk_buff *skb;
	int retval;
	__u16 mlen;

        if (ppos != &file->f_pos)
		return -ESPIPE;

	if (!cdev->applid)
		return -ENODEV;

	skb = alloc_skb(count, GFP_USER);

	if ((retval = copy_from_user(skb_put(skb, count), buf, count))) {
		kfree_skb(skb);
		return retval;
	}
	mlen = CAPIMSG_LEN(skb->data);
	if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_REQ) {
		if (mlen + CAPIMSG_DATALEN(skb->data) != count) {
			kfree_skb(skb);
			return -EINVAL;
		}
	} else {
		if (mlen != count) {
			kfree_skb(skb);
			return -EINVAL;
		}
	}
	CAPIMSG_SETAPPID(skb->data, cdev->applid);

	cdev->errcode = (*capifuncs->capi_put_message) (cdev->applid, skb);

	if (cdev->errcode) {
		kfree_skb(skb);
		return -EIO;
	}
	if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_REQ) {
		cdev->nsentdatapkt++;
	} else {
		cdev->nsentctlpkt++;
	}
	return count;
}

static unsigned int
capi_poll(struct file *file, poll_table * wait)
{
	struct capidev *cdev = (struct capidev *)file->private_data;
	unsigned int mask = 0;

	if (!cdev->applid)
		return POLLERR;

	poll_wait(file, &(cdev->recvwait), wait);
	mask = POLLOUT | POLLWRNORM;
	if (!skb_queue_empty(&cdev->recvqueue))
		mask |= POLLIN | POLLRDNORM;
	return mask;
}

static int
capi_ioctl(struct inode *inode, struct file *file,
		      unsigned int cmd, unsigned long arg)
{
	struct capidev *cdev = (struct capidev *)file->private_data;
	capi_ioctl_struct data;
	int retval = -EINVAL;

	switch (cmd) {
	case CAPI_REGISTER:
		{
			retval = copy_from_user((void *) &data.rparams,
						(void *) arg, sizeof(struct capi_register_params));
			if (retval)
				return -EFAULT;
			if (cdev->applid)
				return -EEXIST;
			cdev->errcode = (*capifuncs->capi_register) (&data.rparams,
							  &cdev->applid);
			if (cdev->errcode) {
				cdev->applid = 0;
				return -EIO;
			}
			(void) (*capifuncs->capi_set_signal) (cdev->applid, capi_signal, cdev);
		}
		return (int)cdev->applid;

	case CAPI_GET_VERSION:
		{
			retval = copy_from_user((void *) &data.contr,
						(void *) arg,
						sizeof(data.contr));
			if (retval)
				return -EFAULT;
		        cdev->errcode = (*capifuncs->capi_get_version) (data.contr, &data.version);
			if (cdev->errcode)
				return -EIO;
			retval = copy_to_user((void *) arg,
					      (void *) &data.version,
					      sizeof(data.version));
			if (retval)
				return -EFAULT;
		}
		return 0;

	case CAPI_GET_SERIAL:
		{
			retval = copy_from_user((void *) &data.contr,
						(void *) arg,
						sizeof(data.contr));
			if (retval)
				return -EFAULT;
			cdev->errcode = (*capifuncs->capi_get_serial) (data.contr, data.serial);
			if (cdev->errcode)
				return -EIO;
			retval = copy_to_user((void *) arg,
					      (void *) data.serial,
					      sizeof(data.serial));
			if (retval)
				return -EFAULT;
		}
		return 0;
	case CAPI_GET_PROFILE:
		{
			retval = copy_from_user((void *) &data.contr,
						(void *) arg,
						sizeof(data.contr));
			if (retval)
				return -EFAULT;

			if (data.contr == 0) {
				cdev->errcode = (*capifuncs->capi_get_profile) (data.contr, &data.profile);
				if (cdev->errcode)
					return -EIO;