drivers/staging/usbip/usbip_common.c

/*
 * Copyright (C) 2003-2008 Takahiro Hirofuchi
 *
 * This 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 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.
 */

#include <linux/kernel.h>
#include <linux/file.h>
#include <linux/tcp.h>
#include <linux/in.h>
#include "usbip_common.h"

/* version information */
#define DRIVER_VERSION "1.0"
#define DRIVER_AUTHOR "Takahiro Hirofuchi <hirofuchi _at_ users.sourceforge.net>"
#define DRIVER_DESC "usbip common driver"

/*-------------------------------------------------------------------------*/
/* debug routines */

#ifdef CONFIG_USB_DEBUG
unsigned long usbip_debug_flag = 0xffffffff;
#else
unsigned long usbip_debug_flag;
#endif
EXPORT_SYMBOL_GPL(usbip_debug_flag);


/* FIXME */
struct device_attribute dev_attr_usbip_debug;
EXPORT_SYMBOL_GPL(dev_attr_usbip_debug);


static ssize_t show_flag(struct device *dev, struct device_attribute *attr,
								char *buf)
{
	return sprintf(buf, "%lx\n", usbip_debug_flag);
}

static ssize_t store_flag(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t count)
{
	unsigned long flag;

	sscanf(buf, "%lx", &flag);
	usbip_debug_flag = flag;

	return count;
}
DEVICE_ATTR(usbip_debug, (S_IRUGO | S_IWUSR), show_flag, store_flag);

static void usbip_dump_buffer(char *buff, int bufflen)
{
	int i;

	if (bufflen > 128) {
		for (i = 0; i < 128; i++) {
			if (i%24 == 0)
				printk("   ");
			printk("%02x ", (unsigned char) buff[i]);
			if (i%4 == 3)
				printk("| ");
			if (i%24 == 23)
				printk("\n");
		}
		printk("... (%d byte)\n", bufflen);
		return;
	}

	for (i = 0; i < bufflen; i++) {
		if (i%24 == 0)
			printk("   ");
		printk("%02x ", (unsigned char) buff[i]);
		if (i%4 == 3)
			printk("| ");
		if (i%24 == 23)
			printk("\n");
	}
	printk("\n");

}

static void usbip_dump_pipe(unsigned int p)
{
	unsigned char type = usb_pipetype(p);
	unsigned char ep = usb_pipeendpoint(p);
	unsigned char dev = usb_pipedevice(p);
	unsigned char dir = usb_pipein(p);

	printk("dev(%d) ", dev);
	printk("ep(%d) ",  ep);
	printk("%s ", dir ? "IN" : "OUT");

	switch (type) {
	case PIPE_ISOCHRONOUS:
		printk("%s ", "ISO");
		break;
	case PIPE_INTERRUPT:
		printk("%s ", "INT");
		break;
	case PIPE_CONTROL:
		printk("%s ", "CTL");
		break;
	case PIPE_BULK:
		printk("%s ", "BLK");
		break;
	default:
		printk("ERR");
	}

	printk("\n");

}

static void usbip_dump_usb_device(struct usb_device *udev)
{
	struct device *dev = &udev->dev;
	int i;

	dev_dbg(dev, "       devnum(%d) devpath(%s)",
		udev->devnum, udev->devpath);

	switch (udev->speed) {
	case USB_SPEED_HIGH:
		printk(" SPD_HIGH");
		break;
	case USB_SPEED_FULL:
		printk(" SPD_FULL");
		break;
	case USB_SPEED_LOW:
		printk(" SPD_LOW");
		break;
	case USB_SPEED_UNKNOWN:
		printk(" SPD_UNKNOWN");
		break;
	default:
		printk(" SPD_ERROR");
	}

	printk(" tt %p, ttport %d", udev->tt, udev->ttport);
	printk("\n");

	dev_dbg(dev, "                    ");
	for (i = 0; i < 16; i++)
		printk(" %2u", i);
	printk("\n");

	dev_dbg(dev, "       toggle0(IN) :");
	for (i = 0; i < 16; i++)
		printk(" %2u", (udev->toggle[0] & (1 << i)) ? 1 : 0);
	printk("\n");

	dev_dbg(dev, "       toggle1(OUT):");
	for (i = 0; i < 16; i++)
		printk(" %2u", (udev->toggle[1] & (1 << i)) ? 1 : 0);
	printk("\n");


	dev_dbg(dev, "       epmaxp_in   :");
	for (i = 0; i < 16; i++) {
		if (udev->ep_in[i])
			printk(" %2u",
			     le16_to_cpu(udev->ep_in[i]->desc.wMaxPacketSize));
	}
	printk("\n");

	dev_dbg(dev, "       epmaxp_out  :");
	for (i = 0; i < 16; i++) {
		if (udev->ep_out[i])
			printk(" %2u",
			     le16_to_cpu(udev->ep_out[i]->desc.wMaxPacketSize));
	}
	printk("\n");

	dev_dbg(dev, "parent %p, bus %p\n", udev->parent, udev->bus);

	dev_dbg(dev, "descriptor %p, config %p, actconfig %p, "
		"rawdescriptors %p\n", &udev->descriptor, udev->config,
		udev->actconfig, udev->rawdescriptors);

	dev_dbg(dev, "have_langid %d, string_langid %d\n",
		udev->have_langid, udev->string_langid);

	dev_dbg(dev, "maxchild %d, children %p\n",
		udev->maxchild, udev->children);
}

static void usbip_dump_request_type(__u8 rt)
{
	switch (rt & USB_RECIP_MASK) {
	case USB_RECIP_DEVICE:
		printk("DEVICE");
		break;
	case USB_RECIP_INTERFACE:
		printk("INTERF");
		break;
	case USB_RECIP_ENDPOINT:
		printk("ENDPOI");
		break;
	case USB_RECIP_OTHER:
		printk("OTHER ");
		break;
	default:
		printk("------");
	}
}

static void usbip_dump_usb_ctrlrequest(struct usb_ctrlrequest *cmd)
{
	if (!cmd) {
		printk("      %s : null pointer\n", __func__);
		return;
	}

	printk("       ");
	printk("bRequestType(%02X) ", cmd->bRequestType);
	printk("bRequest(%02X) " , cmd->bRequest);
	printk("wValue(%04X) ", cmd->wValue);
	printk("wIndex(%04X) ", cmd->wIndex);
	printk("wLength(%04X) ", cmd->wLength);

	printk("\n       ");

	if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
		printk("STANDARD ");
		switch (cmd->bRequest) {
		case USB_REQ_GET_STATUS:
			printk("GET_STATUS");
			break;
		case USB_REQ_CLEAR_FEATURE:
			printk("CLEAR_FEAT");
			break;
		case USB_REQ_SET_FEATURE:
			printk("SET_FEAT  ");
			break;
		case USB_REQ_SET_ADDRESS:
			printk("SET_ADDRRS");
			break;
		case USB_REQ_GET_DESCRIPTOR:
			printk("GET_DESCRI");
			break;
		case USB_REQ_SET_DESCRIPTOR:
			printk("SET_DESCRI");
			break;
		case USB_REQ_GET_CONFIGURATION:
			printk("GET_CONFIG");
			break;
		case USB_REQ_SET_CONFIGURATION:
			printk("SET_CONFIG");
			break;
		case USB_REQ_GET_INTERFACE:
			printk("GET_INTERF");
			break;
		case USB_REQ_SET_INTERFACE:
			printk("SET_INTERF");
			break;
		case USB_REQ_SYNCH_FRAME:
			printk("SYNC_FRAME");
			break;
		default:
			printk("REQ(%02X) ", cmd->bRequest);
		}

		printk(" ");
		usbip_dump_request_type(cmd->bRequestType);

	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS)
		printk("CLASS   ");

	else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_VENDOR)
		printk("VENDOR  ");

	else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_RESERVED)
		printk("RESERVED");

	printk("\n");
}

void usbip_dump_urb(struct urb *urb)
{
	struct device *dev;

	if (!urb) {
		printk(KERN_DEBUG KBUILD_MODNAME
		       ":%s: urb: null pointer!!\n", __func__);
		return;
	}

	if (!urb->dev) {
		printk(KERN_DEBUG KBUILD_MODNAME
		       ":%s: urb->dev: null pointer!!\n", __func__);
		return;
	}
	dev = &urb->dev->dev;

	dev_dbg(dev, "   urb                   :%p\n", urb);
	dev_dbg(dev, "   dev                   :%p\n", urb->dev);

	usbip_dump_usb_device(urb->dev);

	dev_dbg(dev, "   pipe                  :%08x ", urb->pipe);

	usbip_dump_pipe(urb->pipe);

	dev_dbg(dev, "   status                :%d\n", urb->status);
	dev_dbg(dev, "   transfer_flags        :%08X\n", urb->transfer_flags);
	dev_dbg(dev, "   transfer_buffer       :%p\n", urb->transfer_buffer);
	dev_dbg(dev, "   transfer_buffer_length:%d\n", urb->transfer_buffer_length);
	dev_dbg(dev, "   actual_length         :%d\n", urb->actual_length);
	dev_dbg(dev, "   setup_packet          :%p\n", urb->setup_packet);

	if (urb->setup_packet && usb_pipetype(urb->pipe) == PIPE_CONTROL)
			usbip_dump_usb_ctrlrequest(
			(struct usb_ctrlrequest *)urb->setup_packet);

	dev_dbg(dev, "   start_frame           :%d\n", urb->start_frame);
	dev_dbg(dev, "   number_of_packets     :%d\n", urb->number_of_packets);
	dev_dbg(dev, "   interval              :%d\n", urb->interval);
	dev_dbg(dev, "   error_count           :%d\n", urb->error_count);
	dev_dbg(dev, "   context               :%p\n", urb->context);
	dev_dbg(dev, "   complete              :%p\n", urb->complete);
}
EXPORT_SYMBOL_GPL(usbip_dump_urb);

void usbip_dump_header(struct usbip_header *pdu)
{
	udbg("BASE: cmd %u seq %u devid %u dir %u ep %u\n",
			pdu->base.command,
			pdu->base.seqnum,
			pdu->base.devid,
			pdu->base.direction,
			pdu->base.ep);

	switch (pdu->base.command) {
	case USBIP_CMD_SUBMIT:
		udbg("CMD_SUBMIT: x_flags %u x_len %u sf %u #p %u iv %u\n",
				pdu->u.cmd_submit.transfer_flags,
				pdu->u.cmd_submit.transfer_buffer_length,
				pdu->u.cmd_submit.start_frame,
				pdu->u.cmd_submit.number_of_packets,
				pdu->u.cmd_submit.interval);
				break;
	case USBIP_CMD_UNLINK:
		udbg("CMD_UNLINK: seq %u\n", pdu->u.cmd_unlink.seqnum);
		break;
	case USBIP_RET_SUBMIT:
		udbg("RET_SUBMIT: st %d al %u sf %d ec %d\n",
				pdu->u.ret_submit.status,
				pdu->u.ret_submit.actual_length,
				pdu->u.ret_submit.start_frame,
				pdu->u.ret_submit.error_count);
	case USBIP_RET_UNLINK:
		udbg("RET_UNLINK: status %d\n", pdu->u.ret_unlink.status);
		break;
	default:
		/* NOT REACHED */
		udbg("UNKNOWN\n");
	}
}
EXPORT_SYMBOL_GPL(usbip_dump_header);


/*-------------------------------------------------------------------------*/
/* thread routines */

int usbip_thread(void *param)
{
	struct usbip_task *ut = param;

	if (!ut)
		return -EINVAL;

	lock_kernel();
	daemonize(ut->name);
	allow_signal(SIGKILL);
	ut->thread = current;
	unlock_kernel();

	/* srv.rb must wait for rx_thread starting */
	complete(&ut->thread_done);

	/* start of while loop */
	ut->loop_ops(ut);

	/* end of loop */
	ut->thread = NULL;

	complete_and_exit(&ut->thread_done, 0);
}

void usbip_start_threads(struct usbip_device *ud)
{
	/*
	 * threads are invoked per one device (per one connection).
	 */
	int retval;

	retval = kernel_thread(usbip_thread, (void *)&ud->tcp_rx, 0);
	if (retval < 0) {
		printk(KERN_ERR "Creating tcp_rx thread for ud %p failed.\n",
				ud);
		return;
	}
	retval = kernel_thread(usbip_thread, (void *)&ud->tcp_tx, 0);
	if (retval < 0) {
		printk(KERN_ERR "Creating tcp_tx thread for ud %p failed.\n",
				ud);
		return;
	}

	/* confirm threads are starting */
	wait_for_completion(&ud->tcp_rx.thread_done);
	wait_for_completion(&ud->tcp_tx.thread_done);
}
EXPORT_SYMBOL_GPL(usbip_start_threads);

void usbip_stop_threads(struct usbip_device *ud)
{
	/* kill threads related to this sdev, if v.c. exists */
	if (ud->tcp_rx.thread != NULL) {
		send_sig(SIGKILL, ud->tcp_rx.thread, 1);
		wait_for_completion(&ud->tcp_rx.thread_done);
		udbg("rx_thread for ud %p has finished\n", ud);
	}

	if (ud->tcp_tx.thread != NULL) {
		send_sig(SIGKILL, ud->tcp_tx.thread, 1);
		wait_for_completion(&ud->tcp_tx.thread_done);
		udbg("tx_thread for ud %p has finished\n", ud);
	}
}
EXPORT_SYMBOL_GPL(usbip_stop_threads);

void usbip_task_init(struct usbip_task *ut, char *name,
		void (*loop_ops)(struct usbip_task *))
{
	ut->thread = NULL;
	init_completion(&ut->thread_done);
	ut->name = name;
	ut->loop_ops = loop_ops;
}
EXPORT_SYMBOL_GPL(usbip_task_init);


/*-------------------------------------------------------------------------*/
/* socket routines */

 /*  Send/receive messages over TCP/IP. I refer drivers/block/nbd.c */
int usbip_xmit(int send, struct socket *sock, char *buf,
	       int size, int msg_flags)
{
	int result;
	struct msghdr msg;
	struct kvec iov;
	int total = 0;

	/* for blocks of if (dbg_flag_xmit) */
	char *bp = buf;
	int osize = size;

	dbg_xmit("enter\n");

	if (!sock || !buf || !size) {
		printk(KERN_ERR "%s: invalid arg, sock %p buff %p size %d\n",
		       __func__, sock, buf, size);
		return -EINVAL;
	}


	if (dbg_flag_xmit) {
		if (send) {
			if (!in_interrupt())
				printk(KERN_DEBUG "%-10s:", current->comm);
			else
				printk(KERN_DEBUG "interupt  :");

			printk("%s: sending... , sock %p, buf %p, "
			       "size %d, msg_flags %d\n", __func__,
			       sock, buf, size, msg_flags);
			usbip_dump_buffer(buf, size);
		}
	}


	do {
		sock->sk->sk_allocation = GFP_NOIO;
		iov.iov_base    = buf;
		iov.iov_len     = size;
		msg.msg_name    = NULL;
		msg.msg_namelen = 0;
		msg.msg_control = NULL;
		msg.msg_controllen = 0;
		msg.msg_namelen    = 0;
		msg.msg_flags      = msg_flags | MSG_NOSIGNAL;

		if (send)
			result = kernel_sendmsg(sock, &msg, &iov, 1, size);
		else
			result = kernel_recvmsg(sock, &msg, &iov, 1, size,
								MSG_WAITALL);

		if (result <= 0) {
			udbg("usbip_xmit: %s sock %p buf %p size %u ret %d"
					" total %d\n",
					send ? "send" : "receive", sock, buf,
					size, result, total);
			goto err;
		}

		size -= result;
		buf += result;
		total += result;

	} while (size > 0);


	if (dbg_flag_xmit) {
		if (!send) {
			if (!in_interrupt())
				printk(KERN_DEBUG "%-10s:", current->comm);
			else
				printk(KERN_DEBUG "interupt  :");

			printk("usbip_xmit: receiving....\n");
			usbip_dump_buffer(bp, osize);
			printk("usbip_xmit: received, osize %d ret %d size %d "
					"total %d\n", osize, result, size,
					total);
		}

		if (send)
			printk("usbip_xmit: send, total %d\n", total);
	}

	return total;

err:
	return result;
}
EXPORT_SYMBOL_GPL(usbip_xmit);


/* now a usrland utility should set options. */
#if 0
int setquickack(struct socket *socket)
{
	mm_segment_t oldfs;
	int val = 1;
	int ret;

	oldfs = get_fs();
	set_fs(get_ds());
	ret = socket->ops->setsockopt(socket, SOL_TCP, TCP_QUICKACK,
			(char __user *) &val, sizeof(ret));
	set_fs(oldfs);

	return ret;
}

int setnodelay(struct socket *socket)
{
	mm_segment_t oldfs;
	int val = 1;
	int ret;

	oldfs = get_fs();
	set_fs(get_ds());
	ret = socket->ops->setsockopt(socket, SOL_TCP, TCP_NODELAY,
			(char __user *) &val, sizeof(ret));
	set_fs(oldfs);

	return ret;
}

int setkeepalive(struct socket *socket)
{
	mm_segment_t oldfs;
	int val = 1;
	int ret;

	oldfs = get_fs();
	set_fs(get_ds());
	ret = socket->ops->setsockopt(socket, SOL_SOCKET, SO_KEEPALIVE,
			(char __user *) &val, sizeof(ret));
	set_fs(oldfs);

	return ret;
}

void setreuse(struct socket *socket)
{
	socket->sk->sk_reuse = 1;
}
#endif

struct socket *sockfd_to_socket(unsigned int sockfd)
{
	struct socket *socket;
	struct file *file;
	struct inode *inode;

	file = fget(sockfd);
	if (!file) {
		printk(KERN_ERR "%s: invalid sockfd\n", __func__);
		return NULL;
	}

	inode = file->f_dentry->d_inode;

	if (!inode || !S_ISSOCK(inode->i_mode))
		return NULL;

	socket = SOCKET_I(inode);

	return socket;
}
EXPORT_SYMBOL_GPL(sockfd_to_socket);



/*-------------------------------------------------------------------------*/
/* pdu routines */

/* there may be more cases to tweak the flags. */
static unsigned int tweak_transfer_flags(unsigned int flags)
{

	if (flags & URB_NO_TRANSFER_DMA_MAP)
		/*
		 * vhci_hcd does not provide DMA-mapped I/O. The upper
		 * driver does not need to set this flag. The remote
		 * usbip.ko does not still perform DMA-mapped I/O for
		 * DMA-caplable host controllers. So, clear this flag.
		 */
		flags &= ~URB_NO_TRANSFER_DMA_MAP;

	if (flags & URB_NO_SETUP_DMA_MAP)
		flags &= ~URB_NO_SETUP_DMA_MAP;

	return flags;
}

static void usbip_pack_cmd_submit(struct usbip_header *pdu, struct urb *urb,
								int pack)
{
	struct usbip_header_cmd_submit *spdu = &pdu->u.cmd_submit;

	/*
	 * Some members are not still implemented in usbip. I hope this issue
	 * will be discussed when usbip is ported to other operating systems.
	 */
	if (pack) {
		/* vhci_tx.c */
		spdu->transfer_flags =
				tweak_transfer_flags(urb->transfer_flags);
		spdu->transfer_buffer_length	= urb->transfer_buffer_length;
		spdu->start_frame		= urb->start_frame;
		spdu->number_of_packets		= urb->number_of_packets;
		spdu->interval			= urb->interval;
	} else  {
		/* stub_rx.c */
		urb->transfer_flags         = spdu->transfer_flags;

		urb->transfer_buffer_length = spdu->transfer_buffer_length;
		urb->start_frame            = spdu->start_frame;
		urb->number_of_packets      = spdu->number_of_packets;
		urb->interval               = spdu->interval;
	}
}

static void usbip_pack_ret_submit(struct usbip_header *pdu, struct urb *urb,
								int pack)
{
	struct usbip_header_ret_submit *rpdu = &pdu->u.ret_submit;

	if (pack) {
		/* stub_tx.c */

		rpdu->status		= urb->status;
		rpdu->actual_length	= urb->actual_length;
		rpdu->start_frame	= urb->start_frame;
		rpdu->error_count	= urb->error_count;
	} else {
		/* vhci_rx.c */

		urb->status		= rpdu->status;
		urb->actual_length	= rpdu->actual_length;
		urb->start_frame	= rpdu->start_frame;
		urb->error_count	= rpdu->error_count;
	}
}


void usbip_pack_pdu(struct usbip_header *pdu, struct urb *urb, int cmd,
								int pack)
{
	switch (cmd) {
	case USBIP_CMD_SUBMIT:
		usbip_pack_cmd_submit(pdu, urb, pack);
		break;
	case USBIP_RET_SUBMIT:
		usbip_pack_ret_submit(pdu, urb, pack);
		break;
	default:
		err("unknown command");
		/* NOTREACHED */
		/* BUG(); */
	}
}
EXPORT_SYMBOL_GPL(usbip_pack_pdu);


static void correct_endian_basic(struct usbip_header_basic *base, int send)
{
	if (send) {
		base->command	= cpu_to_be32(base->command);
		base->seqnum	= cpu_to_be32(base->seqnum);
		base->devid	= cpu_to_be32(base->devid);
		base->direction	= cpu_to_be32(base->direction);
		base->ep	= cpu_to_be32(base->ep);
	} else {
		base->command	= be32_to_cpu(base->command);
		base->seqnum	= be32_to_cpu(base->seqnum);
		base->devid	= be32_to_cpu(base->devid);
		base->direction	= be32_to_cpu(base->direction);
		base->ep	= be32_to_cpu(base->ep);
	}
}

static void correct_endian_cmd_submit(struct usbip_header_cmd_submit *pdu,
								int send)
{
	if (send) {
		pdu->transfer_flags = cpu_to_be32(pdu->transfer_flags);

		cpu_to_be32s(&pdu->transfer_buffer_length);
		cpu_to_be32s(&pdu->start_frame);
		cpu_to_be32s(&pdu->number_of_packets);
		cpu_to_be32s(&pdu->interval);
	} else {
		pdu->transfer_flags = be32_to_cpu(pdu->transfer_flags);

		be32_to_cpus(&pdu->transfer_buffer_length);
		be32_to_cpus(&pdu->start_frame);
		be32_to_cpus(&pdu->number_of_packets);
		be32_to_cpus(&pdu->interval);
	}
}

static void correct_endian_ret_submit(struct usbip_header_ret_submit *pdu,
								int send)
{
	if (send) {
		cpu_to_be32s(&pdu->status);
		cpu_to_be32s(&pdu->actual_length);
		cpu_to_be32s(&pdu->start_frame);
		cpu_to_be32s(&pdu->error_count);
	} else {
		be32_to_cpus(&pdu->status);
		be32_to_cpus(&pdu->actual_length);
		be32_to_cpus(&pdu->start_frame);
		be32_to_cpus(&pdu->error_count);
	}
}

static void correct_endian_cmd_unlink(struct usbip_header_cmd_unlink *pdu,
								int send)
{
	if (send)
		pdu->seqnum = cpu_to_be32(pdu->seqnum);
	else
		pdu->seqnum = be32_to_cpu(pdu->seqnum);
}

static void correct_endian_ret_unlink(struct usbip_header_ret_unlink *pdu,
								int send)
{
	if (send)
		cpu_to_be32s(&pdu->status);
	else
		be32_to_cpus(&pdu->status);
}

void usbip_header_correct_endian(struct usbip_header *pdu, int send)
{
	__u32 cmd = 0;

	if (send)
		cmd = pdu->base.command;

	correct_endian_basic(&pdu->base, send);

	if (!send)
		cmd = pdu->base.command;

	switch (cmd) {
	case USBIP_CMD_SUBMIT:
		correct_endian_cmd_submit(&pdu->u.cmd_submit, send);
		break;
	case USBIP_RET_SUBMIT:
		correct_endian_ret_submit(&pdu->u.ret_submit, send);
		break;
	case USBIP_CMD_UNLINK:
		correct_endian_cmd_unlink(&pdu->u.cmd_unlink, send);
		break;
	case USBIP_RET_UNLINK:
		correct_endian_ret_unlink(&pdu->u.ret_unlink, send);
		break;
	default:
		/* NOTREACHED */
		err("unknown command in pdu header: %d", cmd);
		/* BUG(); */
	}
}
EXPORT_SYMBOL_GPL(usbip_header_correct_endian);

static void usbip_iso_pakcet_correct_endian(
				struct usbip_iso_packet_descriptor *iso,
				int send)
{
	/* does not need all members. but copy all simply. */
	if (send) {
		iso->offset	= cpu_to_be32(iso->offset);
		iso->length	= cpu_to_be32(iso->length);
		iso->status	= cpu_to_be32(iso->status);
		iso->actual_length = cpu_to_be32(iso->actual_length);
	} else {
		iso->offset	= be32_to_cpu(iso->offset);
		iso->length	= be32_to_cpu(iso->length);
		iso->status	= be32_to_cpu(iso->status);
		iso->actual_length = be32_to_cpu(iso->actual_length);
	}
}

static void usbip_pack_iso(struct usbip_iso_packet_descriptor *iso,
		struct usb_iso_packet_descriptor *uiso, int pack)
{
	if (pack) {
		iso->offset		= uiso->offset;
		iso->length		= uiso->length;
		iso->status		= uiso->status;
		iso->actual_length	= uiso->actual_length;
	} else {
		uiso->offset		= iso->offset;
		uiso->length		= iso->length;
		uiso->status		= iso->status;
		uiso->actual_length	= iso->actual_length;
	}
}


/* must free buffer */
void *usbip_alloc_iso_desc_pdu(struct urb *urb, ssize_t *bufflen)
{
	void *buff;
	struct usbip_iso_packet_descriptor *iso;
	int np = urb->number_of_packets;
	ssize_t size = np * sizeof(*iso);
	int i;

	buff = kzalloc(size, GFP_KERNEL);
	if (!buff)
		return NULL;

	for (i = 0; i < np; i++) {
		iso = buff + (i * sizeof(*iso));

		usbip_pack_iso(iso, &urb->iso_frame_desc[i], 1);
		usbip_iso_pakcet_correct_endian(iso, 1);
	}

	*bufflen = size;

	return buff;
}
EXPORT_SYMBOL_GPL(usbip_alloc_iso_desc_pdu);

/* some members of urb must be substituted before. */
int usbip_recv_iso(struct usbip_device *ud, struct urb *urb)
{
	void *buff;
	struct usbip_iso_packet_descriptor *iso;
	int np = urb->number_of_packets;
	int size = np * sizeof(*iso);
	int i;
	int ret;

	if (!usb_pipeisoc(urb->pipe))
		return 0;

	/* my Bluetooth dongle gets ISO URBs which are np = 0 */
	if (np == 0) {
		/* uinfo("iso np == 0\n"); */
		/* usbip_dump_urb(urb); */
		return 0;
	}

	buff = kzalloc(size, GFP_KERNEL);
	if (!buff)
		return -ENOMEM;

	ret = usbip_xmit(0, ud->tcp_socket, buff, size, 0);
	if (ret != size) {
		dev_err(&urb->dev->dev, "recv iso_frame_descriptor, %d\n",
			ret);
		kfree(buff);

		if (ud->side == USBIP_STUB)
			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
		else
			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);

		return -EPIPE;
	}

	for (i = 0; i < np; i++) {
		iso = buff + (i * sizeof(*iso));

		usbip_iso_pakcet_correct_endian(iso, 0);
		usbip_pack_iso(iso, &urb->iso_frame_desc[i], 0);
	}


	kfree(buff);

	return ret;
}
EXPORT_SYMBOL_GPL(usbip_recv_iso);


/* some members of urb must be substituted before. */
int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
{
	int ret;
	int size;

	if (ud->side == USBIP_STUB) {
		/* stub_rx.c */
		/* the direction of urb must be OUT. */
		if (usb_pipein(urb->pipe))
			return 0;

		size = urb->transfer_buffer_length;
	} else {
		/* vhci_rx.c */
		/* the direction of urb must be IN. */
		if (usb_pipeout(urb->pipe))
			return 0;

		size = urb->actual_length;
	}

	/* no need to recv xbuff */
	if (!(size > 0))
		return 0;

	ret = usbip_xmit(0, ud->tcp_socket, (char *)urb->transfer_buffer,
			 size, 0);
	if (ret != size) {
		dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
		if (ud->side == USBIP_STUB) {
			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
		} else {
			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
			return -EPIPE;
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(usbip_recv_xbuff);


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

static int __init usbip_common_init(void)
{
	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "" DRIVER_VERSION);

	return 0;
}

static void __exit usbip_common_exit(void)
{
	return;
}




module_init(usbip_common_init);
module_exit(usbip_common_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");