netiucv.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

/**
 * Transmit a packet.
 * This is a helper function for netiucv_tx().
 *
 * @param conn Connection to be used for sending.
 * @param skb Pointer to struct sk_buff of packet to send.
 *            The linklevel header has already been set up
 *            by netiucv_tx().
 *
 * @return 0 on success, -ERRNO on failure. (Never fails.)
 */
static int
netiucv_transmit_skb(iucv_connection *conn, struct sk_buff *skb) {
	unsigned long saveflags;
	ll_header header;
	int       rc = 0;

	if (fsm_getstate(conn->fsm) != CONN_STATE_IDLE) {
		int l = skb->len + NETIUCV_HDRLEN;

		spin_lock_irqsave(&conn->collect_lock, saveflags);
		if (conn->collect_len + l >
		    (conn->max_buffsize - NETIUCV_HDRLEN))
			rc = -EBUSY;
		else {
			atomic_inc(&skb->users);
			skb_queue_tail(&conn->collect_queue, skb);
			conn->collect_len += l;
		}
		spin_unlock_irqrestore(&conn->collect_lock, saveflags);
	} else {
		struct sk_buff *nskb = skb;
		/**
		 * Copy the skb to a new allocated skb in lowmem only if the
		 * data is located above 2G in memory or tailroom is < 2.
		 */
		unsigned long hi =
			((unsigned long)(skb->tail + NETIUCV_HDRLEN)) >> 31;
		int copied = 0;
		if (hi || (skb_tailroom(skb) < 2)) {
			nskb = alloc_skb(skb->len + NETIUCV_HDRLEN +
					 NETIUCV_HDRLEN, GFP_ATOMIC | GFP_DMA);
			if (!nskb) {
				printk(KERN_WARNING
				       "%s: Could not allocate tx_skb\n",
				       conn->netdev->name);
				rc = -ENOMEM;
			} else {
				skb_reserve(nskb, NETIUCV_HDRLEN);
				memcpy(skb_put(nskb, skb->len),
				       skb->data, skb->len);
			}
			copied = 1;
		}
		/**
		 * skb now is below 2G and has enough room. Add headers.
		 */
		header.next = nskb->len + NETIUCV_HDRLEN;
		memcpy(skb_push(nskb, NETIUCV_HDRLEN), &header, NETIUCV_HDRLEN);
		header.next = 0;
		memcpy(skb_put(nskb, NETIUCV_HDRLEN), &header,  NETIUCV_HDRLEN);

		conn->retry = 0;
		fsm_newstate(conn->fsm, CONN_STATE_TX);
		fsm_addtimer(&conn->timer, NETIUCV_TIMEOUT_5SEC,
			     CONN_EVENT_TIMER, conn);
		conn->prof.send_stamp = xtime;
		
		rc = iucv_send(conn->pathid, NULL, 0, 0,
			       /* Shut up, gcc! nskb is always below 2G. */
			       (__u32)(((unsigned long)nskb)&0xffffffff), 0,
			       nskb->data, nskb->len);
		conn->prof.doios_single++;
		conn->prof.txlen += skb->len;
		if (rc != 0) {
			fsm_deltimer(&conn->timer);
			if (copied)
				dev_kfree_skb(nskb);
			else {
				/**
				 * Remove our headers. They get added
				 * again on retransmit.
				 */
				skb_pull(skb, NETIUCV_HDRLEN);
				skb_trim(skb, skb->len - NETIUCV_HDRLEN);
			}
		} else {
			if (copied)
				dev_kfree_skb(skb);
		}
	}

	return rc;
}

/**
 * Interface API for upper network layers
 *****************************************************************************/

/**
 * Open an interface.
 * Called from generic network layer when ifconfig up is run.
 *
 * @param dev Pointer to interface struct.
 *
 * @return 0 on success, -ERRNO on failure. (Never fails.)
 */
static int
netiucv_open(net_device *dev) {
	MOD_INC_USE_COUNT;
	SET_DEVICE_START(dev, 1);
	fsm_event(((netiucv_priv *)dev->priv)->fsm, DEV_EVENT_START, dev);
	return 0;
}

/**
 * Close an interface.
 * Called from generic network layer when ifconfig down is run.
 *
 * @param dev Pointer to interface struct.
 *
 * @return 0 on success, -ERRNO on failure. (Never fails.)
 */
static int
netiucv_close(net_device *dev) {
	SET_DEVICE_START(dev, 0);
	fsm_event(((netiucv_priv *)dev->priv)->fsm, DEV_EVENT_STOP, dev);
	MOD_DEC_USE_COUNT;
	return 0;
}

/**
 * Start transmission of a packet.
 * Called from generic network device layer.
 *
 * @param skb Pointer to buffer containing the packet.
 * @param dev Pointer to interface struct.
 *
 * @return 0 if packet consumed, !0 if packet rejected.
 *         Note: If we return !0, then the packet is free'd by
 *               the generic network layer.
 */
static int netiucv_tx(struct sk_buff *skb, net_device *dev)
{
	int          rc = 0;
	netiucv_priv *privptr = (netiucv_priv *)dev->priv;

	/**
	 * Some sanity checks ...
	 */
	if (skb == NULL) {
		printk(KERN_WARNING "%s: NULL sk_buff passed\n", dev->name);
		privptr->stats.tx_dropped++;
		return 0;
	}
	if (skb_headroom(skb) < (NETIUCV_HDRLEN)) {
		printk(KERN_WARNING
		       "%s: Got sk_buff with head room < %ld bytes\n",
		       dev->name, NETIUCV_HDRLEN);
		dev_kfree_skb(skb);
		privptr->stats.tx_dropped++;
		return 0;
	}

	/**
	 * If connection is not running, try to restart it
	 * notify anybody about a link failure and throw
	 * away packet. 
	 */
	if (fsm_getstate(privptr->fsm) != DEV_STATE_RUNNING) {
		fsm_event(privptr->fsm, DEV_EVENT_START, dev);
		dst_link_failure(skb);
		dev_kfree_skb(skb);
		privptr->stats.tx_dropped++;
		privptr->stats.tx_errors++;
		privptr->stats.tx_carrier_errors++;
		return 0;
	}

	if (netiucv_test_and_set_busy(dev))
		return -EBUSY;

	dev->trans_start = jiffies;
	if (netiucv_transmit_skb(privptr->conn, skb) != 0)
		rc = 1;
	netiucv_clear_busy(dev);
	return rc;
}

/**
 * Returns interface statistics of a device.
 *
 * @param dev Pointer to interface struct.
 *
 * @return Pointer to stats struct of this interface.
 */
static struct net_device_stats *
netiucv_stats (net_device * dev)
{
	return &((netiucv_priv *)dev->priv)->stats;
}

/**
 * Sets MTU of an interface.
 *
 * @param dev     Pointer to interface struct.
 * @param new_mtu The new MTU to use for this interface.
 *
 * @return 0 on success, -EINVAL if MTU is out of valid range.
 *         (valid range is 576 .. NETIUCV_MTU_MAX).
 */
static int
netiucv_change_mtu (net_device * dev, int new_mtu)
{
	if ((new_mtu < 576) || (new_mtu > NETIUCV_MTU_MAX))
		return -EINVAL;
	dev->mtu = new_mtu;
	return 0;
}


/**
 * procfs related structures and routines
 *****************************************************************************/

static net_device *
find_netdev_by_ino(unsigned long ino)
{
	iucv_connection *conn = connections;
	net_device *dev = NULL;
	netiucv_priv *privptr;

	while (conn) {
		if (conn->netdev != dev) {
			dev = conn->netdev;
			privptr = (netiucv_priv *)dev->priv;

			if ((privptr->proc_buffer_entry->low_ino == ino) ||
			    (privptr->proc_user_entry->low_ino == ino)   ||
			    (privptr->proc_stat_entry->low_ino == ino)     )
				return dev;
		}
		conn = conn->next;
	}
	return NULL;
}

#if LINUX_VERSION_CODE < 0x020363
/**
 * Lock the module, if someone changes into
 * our proc directory.
 */
static void
netiucv_fill_inode(struct inode *inode, int fill)
{
	if (fill) {
		MOD_INC_USE_COUNT;
	} else
		MOD_DEC_USE_COUNT;
}
#endif

#define CTRL_BUFSIZE 40

static int
netiucv_buffer_open(struct inode *inode, struct file *file)
{
	file->private_data = kmalloc(CTRL_BUFSIZE, GFP_KERNEL);
	if (file->private_data == NULL)
		return -ENOMEM;
	MOD_INC_USE_COUNT;
	return 0;
}

static int
netiucv_buffer_close(struct inode *inode, struct file *file)
{
	kfree(file->private_data);
	MOD_DEC_USE_COUNT;
	return 0;
}

static ssize_t
netiucv_buffer_write(struct file *file, const char *buf, size_t count,
			   loff_t *off)
{
	unsigned int ino = ((struct inode *)file->f_dentry->d_inode)->i_ino;
	net_device   *dev;
	netiucv_priv *privptr;
	char         *e;
	int          bs1;
	char         tmp[CTRL_BUFSIZE];

	if (!(dev = find_netdev_by_ino(ino)))
		return -ENODEV;
	if (off != &file->f_pos)
		return -ESPIPE;

	privptr = (netiucv_priv *)dev->priv;

	if (count >= 39)
		return -EINVAL;

	if (copy_from_user(tmp, buf, count))
		return -EFAULT;
	tmp[count+1] = '\0';
	bs1 = simple_strtoul(tmp, &e, 0);

	if ((bs1 > NETIUCV_BUFSIZE_MAX) ||
	    (e && (!isspace(*e))))
		return -EINVAL;
	if ((dev->flags & IFF_RUNNING) &&
	    (bs1 < (dev->mtu + NETIUCV_HDRLEN + 2)))
		return -EINVAL;
	if (bs1 < (576 + NETIUCV_HDRLEN + NETIUCV_HDRLEN))
		return -EINVAL;


	privptr->conn->max_buffsize = bs1;
	if (!(dev->flags & IFF_RUNNING))
		dev->mtu = bs1 - NETIUCV_HDRLEN - NETIUCV_HDRLEN;
	privptr->conn->flags |= CONN_FLAGS_BUFSIZE_CHANGED;

	return count;
}

static ssize_t
netiucv_buffer_read(struct file *file, char *buf, size_t count, loff_t *off)
{
	unsigned int ino = ((struct inode *)file->f_dentry->d_inode)->i_ino;
	char *sbuf = (char *)file->private_data;
	net_device *dev;
	netiucv_priv *privptr;
	ssize_t ret = 0;
	char *p = sbuf;
	int l;

	if (!(dev = find_netdev_by_ino(ino)))
		return -ENODEV;
	if (off != &file->f_pos)
		return -ESPIPE;

	privptr = (netiucv_priv *)dev->priv;

	if (file->f_pos == 0)
		sprintf(sbuf, "%d\n", privptr->conn->max_buffsize);

	l = strlen(sbuf);
	p = sbuf;
	if (file->f_pos < l) {
		p += file->f_pos;
		l = strlen(p);
		ret = (count > l) ? l : count;
		if (copy_to_user(buf, p, ret))
			return -EFAULT;
	}
	file->f_pos += ret;
	return ret;
}

static int
netiucv_user_open(struct inode *inode, struct file *file)
{
	file->private_data = kmalloc(CTRL_BUFSIZE, GFP_KERNEL);
	if (file->private_data == NULL)
		return -ENOMEM;
	MOD_INC_USE_COUNT;
	return 0;
}

static int
netiucv_user_close(struct inode *inode, struct file *file)
{
	kfree(file->private_data);
	MOD_DEC_USE_COUNT;
	return 0;
}

static ssize_t
netiucv_user_write(struct file *file, const char *buf, size_t count,
			   loff_t *off)
{
	unsigned int ino = ((struct inode *)file->f_dentry->d_inode)->i_ino;
	net_device   *dev;
	netiucv_priv *privptr;
	int          i;
	char         *p;
	char         tmp[CTRL_BUFSIZE];
	char         user[9];

	if (!(dev = find_netdev_by_ino(ino)))
		return -ENODEV;
	if (off != &file->f_pos)
		return -ESPIPE;

	privptr = (netiucv_priv *)dev->priv;

	if (count >= 39)
		return -EINVAL;

	if (copy_from_user(tmp, buf, count))
		return -EFAULT;
	tmp[count+1] = '\0';

	memset(user, ' ', sizeof(user));
	user[8] = '\0';
	for (p = tmp, i = 0; *p && (!isspace(*p)); p++) {
		if (i > 7)
			return -EINVAL;
		user[i++] = *p;
	}

	if (memcmp(user, privptr->conn->userid, 8) != 0) {
		/* username changed */
		if (dev->flags & IFF_RUNNING)
			return -EBUSY;
	}
	memcpy(privptr->conn->userid, user, 9);
	return count;
}

static ssize_t
netiucv_user_read(struct file *file, char *buf, size_t count, loff_t *off)
{
	unsigned int ino = ((struct inode *)file->f_dentry->d_inode)->i_ino;
	char *sbuf = (char *)file->private_data;
	net_device *dev;
	netiucv_priv *privptr;
	ssize_t ret = 0;
	char *p = sbuf;
	int l;

	if (!(dev = find_netdev_by_ino(ino)))
		return -ENODEV;
	if (off != &file->f_pos)
		return -ESPIPE;

	privptr = (netiucv_priv *)dev->priv;


	if (file->f_pos == 0)
		sprintf(sbuf, "%s\n",
			netiucv_printname(privptr->conn->userid));

	l = strlen(sbuf);
	p = sbuf;
	if (file->f_pos < l) {
		p += file->f_pos;
		l = strlen(p);
		ret = (count > l) ? l : count;
		if (copy_to_user(buf, p, ret))
			return -EFAULT;
	}
	file->f_pos += ret;
	return ret;
}

#define STATS_BUFSIZE 2048

static int
netiucv_stat_open(struct inode *inode, struct file *file)
{
	file->private_data = kmalloc(STATS_BUFSIZE, GFP_KERNEL);
	if (file->private_data == NULL)
		return -ENOMEM;
	MOD_INC_USE_COUNT;
	return 0;
}

static int
netiucv_stat_close(struct inode *inode, struct file *file)
{
	kfree(file->private_data);
	MOD_DEC_USE_COUNT;
	return 0;
}

static ssize_t
netiucv_stat_write(struct file *file, const char *buf, size_t count, loff_t *off)
{
	unsigned int ino = ((struct inode *)file->f_dentry->d_inode)->i_ino;
	net_device *dev;
	netiucv_priv *privptr;

	if (!(dev = find_netdev_by_ino(ino)))
		return -ENODEV;
	privptr = (netiucv_priv *)dev->priv;
	privptr->conn->prof.maxmulti = 0;
	privptr->conn->prof.maxcqueue = 0;
	privptr->conn->prof.doios_single = 0;
	privptr->conn->prof.doios_multi = 0;
	privptr->conn->prof.txlen = 0;
	privptr->conn->prof.tx_time = 0;
	return count;
}

static ssize_t
netiucv_stat_read(struct file *file, char *buf, size_t count, loff_t *off)
{
	unsigned int ino = ((struct inode *)file->f_dentry->d_inode)->i_ino;
	char *sbuf = (char *)file->private_data;
	net_device *dev;
	netiucv_priv *privptr;
	ssize_t ret = 0;
	char *p = sbuf;
	int l;

	if (!(dev = find_netdev_by_ino(ino)))
		return -ENODEV;
	if (off != &file->f_pos)
		return -ESPIPE;

	privptr = (netiucv_priv *)dev->priv;

	if (file->f_pos == 0) {
		p += sprintf(p, "Device FSM state: %s\n",
			     fsm_getstate_str(privptr->fsm));
		p += sprintf(p, "Connection FSM state: %s\n",
			     fsm_getstate_str(privptr->conn->fsm));
		p += sprintf(p, "Max. TX buffer used: %ld\n",
			     privptr->conn->prof.maxmulti);
		p += sprintf(p, "Max. chained SKBs: %ld\n",
			     privptr->conn->prof.maxcqueue);
		p += sprintf(p, "TX single write ops: %ld\n",
			     privptr->conn->prof.doios_single);
		p += sprintf(p, "TX multi write ops: %ld\n",
			     privptr->conn->prof.doios_multi);
		p += sprintf(p, "Netto bytes written: %ld\n",
			     privptr->conn->prof.txlen);
		p += sprintf(p, "Max. TX IO-time: %ld\n",
			     privptr->conn->prof.tx_time);
	}