1 files changed, 778 insertions, 0 deletions

diff --git a/drivers/usb/usbip/usbip_common.c b/drivers/usb/usbip/usbip_common.c
new file mode 100644
index 000000000..88eaf3c45
--- /dev/null
+++ b/drivers/usb/usbip/usbip_common.c
@@ -0,0 +1,778 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2003-2008 Takahiro Hirofuchi
+ * Copyright (C) 2015-2016 Samsung Electronics
+ *               Krzysztof Opasiak <k.opasiak@samsung.com>
+ */
+
+#include <asm/byteorder.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <net/sock.h>
+
+#include "usbip_common.h"
+
+#define DRIVER_AUTHOR "Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>"
+#define DRIVER_DESC "USB/IP Core"
+
+#ifdef CONFIG_USBIP_DEBUG
+unsigned long usbip_debug_flag = 0xffffffff;
+#else
+unsigned long usbip_debug_flag;
+#endif
+EXPORT_SYMBOL_GPL(usbip_debug_flag);
+module_param(usbip_debug_flag, ulong, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(usbip_debug_flag, "debug flags (defined in usbip_common.h)");
+
+/* FIXME */
+struct device_attribute dev_attr_usbip_debug;
+EXPORT_SYMBOL_GPL(dev_attr_usbip_debug);
+
+static ssize_t usbip_debug_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lx\n", usbip_debug_flag);
+}
+
+static ssize_t usbip_debug_store(struct device *dev,
+				 struct device_attribute *attr, const char *buf,
+				 size_t count)
+{
+	if (sscanf(buf, "%lx", &usbip_debug_flag) != 1)
+		return -EINVAL;
+	return count;
+}
+DEVICE_ATTR_RW(usbip_debug);
+
+static void usbip_dump_buffer(char *buff, int bufflen)
+{
+	print_hex_dump(KERN_DEBUG, "usbip-core", DUMP_PREFIX_OFFSET, 16, 4,
+		       buff, bufflen, false);
+}
+
+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);
+
+	pr_debug("dev(%d) ep(%d) [%s] ", dev, ep, dir ? "IN" : "OUT");
+
+	switch (type) {
+	case PIPE_ISOCHRONOUS:
+		pr_debug("ISO\n");
+		break;
+	case PIPE_INTERRUPT:
+		pr_debug("INT\n");
+		break;
+	case PIPE_CONTROL:
+		pr_debug("CTRL\n");
+		break;
+	case PIPE_BULK:
+		pr_debug("BULK\n");
+		break;
+	default:
+		pr_debug("ERR\n");
+		break;
+	}
+}
+
+static void usbip_dump_usb_device(struct usb_device *udev)
+{
+	struct device *dev = &udev->dev;
+	int i;
+
+	dev_dbg(dev, "       devnum(%d) devpath(%s) usb speed(%s)",
+		udev->devnum, udev->devpath, usb_speed_string(udev->speed));
+
+	pr_debug("tt hub ttport %d\n", udev->ttport);
+
+	dev_dbg(dev, "                    ");
+	for (i = 0; i < 16; i++)
+		pr_debug(" %2u", i);
+	pr_debug("\n");
+
+	dev_dbg(dev, "       toggle0(IN) :");
+	for (i = 0; i < 16; i++)
+		pr_debug(" %2u", (udev->toggle[0] & (1 << i)) ? 1 : 0);
+	pr_debug("\n");
+
+	dev_dbg(dev, "       toggle1(OUT):");
+	for (i = 0; i < 16; i++)
+		pr_debug(" %2u", (udev->toggle[1] & (1 << i)) ? 1 : 0);
+	pr_debug("\n");
+
+	dev_dbg(dev, "       epmaxp_in   :");
+	for (i = 0; i < 16; i++) {
+		if (udev->ep_in[i])
+			pr_debug(" %2u",
+			    le16_to_cpu(udev->ep_in[i]->desc.wMaxPacketSize));
+	}
+	pr_debug("\n");
+
+	dev_dbg(dev, "       epmaxp_out  :");
+	for (i = 0; i < 16; i++) {
+		if (udev->ep_out[i])
+			pr_debug(" %2u",
+			    le16_to_cpu(udev->ep_out[i]->desc.wMaxPacketSize));
+	}
+	pr_debug("\n");
+
+	dev_dbg(dev, "parent %s, bus %s\n", dev_name(&udev->parent->dev),
+		udev->bus->bus_name);
+
+	dev_dbg(dev, "have_langid %d, string_langid %d\n",
+		udev->have_langid, udev->string_langid);
+
+	dev_dbg(dev, "maxchild %d\n", udev->maxchild);
+}
+
+static void usbip_dump_request_type(__u8 rt)
+{
+	switch (rt & USB_RECIP_MASK) {
+	case USB_RECIP_DEVICE:
+		pr_debug("DEVICE");
+		break;
+	case USB_RECIP_INTERFACE:
+		pr_debug("INTERF");
+		break;
+	case USB_RECIP_ENDPOINT:
+		pr_debug("ENDPOI");
+		break;
+	case USB_RECIP_OTHER:
+		pr_debug("OTHER ");
+		break;
+	default:
+		pr_debug("------");
+		break;
+	}
+}
+
+static void usbip_dump_usb_ctrlrequest(struct usb_ctrlrequest *cmd)
+{
+	if (!cmd) {
+		pr_debug("       : null pointer\n");
+		return;
+	}
+
+	pr_debug("       ");
+	pr_debug("bRequestType(%02X) bRequest(%02X) wValue(%04X) wIndex(%04X) wLength(%04X) ",
+		 cmd->bRequestType, cmd->bRequest,
+		 cmd->wValue, cmd->wIndex, cmd->wLength);
+	pr_debug("\n       ");
+
+	if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
+		pr_debug("STANDARD ");
+		switch (cmd->bRequest) {
+		case USB_REQ_GET_STATUS:
+			pr_debug("GET_STATUS\n");
+			break;
+		case USB_REQ_CLEAR_FEATURE:
+			pr_debug("CLEAR_FEAT\n");
+			break;
+		case USB_REQ_SET_FEATURE:
+			pr_debug("SET_FEAT\n");
+			break;
+		case USB_REQ_SET_ADDRESS:
+			pr_debug("SET_ADDRRS\n");
+			break;
+		case USB_REQ_GET_DESCRIPTOR:
+			pr_debug("GET_DESCRI\n");
+			break;
+		case USB_REQ_SET_DESCRIPTOR:
+			pr_debug("SET_DESCRI\n");
+			break;
+		case USB_REQ_GET_CONFIGURATION:
+			pr_debug("GET_CONFIG\n");
+			break;
+		case USB_REQ_SET_CONFIGURATION:
+			pr_debug("SET_CONFIG\n");
+			break;
+		case USB_REQ_GET_INTERFACE:
+			pr_debug("GET_INTERF\n");
+			break;
+		case USB_REQ_SET_INTERFACE:
+			pr_debug("SET_INTERF\n");
+			break;
+		case USB_REQ_SYNCH_FRAME:
+			pr_debug("SYNC_FRAME\n");
+			break;
+		default:
+			pr_debug("REQ(%02X)\n", cmd->bRequest);
+			break;
+		}
+		usbip_dump_request_type(cmd->bRequestType);
+	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS) {
+		pr_debug("CLASS\n");
+	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_VENDOR) {
+		pr_debug("VENDOR\n");
+	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_RESERVED) {
+		pr_debug("RESERVED\n");
+	}
+}
+
+void usbip_dump_urb(struct urb *urb)
+{
+	struct device *dev;
+
+	if (!urb) {
+		pr_debug("urb: null pointer!!\n");
+		return;
+	}
+
+	if (!urb->dev) {
+		pr_debug("urb->dev: null pointer!!\n");
+		return;
+	}
+
+	dev = &urb->dev->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_length:%d\n",
+						urb->transfer_buffer_length);
+	dev_dbg(dev, "   actual_length         :%d\n", urb->actual_length);
+
+	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);
+}
+EXPORT_SYMBOL_GPL(usbip_dump_urb);
+
+void usbip_dump_header(struct usbip_header *pdu)
+{
+	pr_debug("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:
+		pr_debug("USBIP_CMD_SUBMIT: x_flags %u x_len %u sf %u #p %d iv %d\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:
+		pr_debug("USBIP_CMD_UNLINK: seq %u\n",
+			 pdu->u.cmd_unlink.seqnum);
+		break;
+	case USBIP_RET_SUBMIT:
+		pr_debug("USBIP_RET_SUBMIT: st %d al %u sf %d #p %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.number_of_packets,
+			 pdu->u.ret_submit.error_count);
+		break;
+	case USBIP_RET_UNLINK:
+		pr_debug("USBIP_RET_UNLINK: status %d\n",
+			 pdu->u.ret_unlink.status);
+		break;
+	default:
+		/* NOT REACHED */
+		pr_err("unknown command\n");
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(usbip_dump_header);
+
+/* Receive data over TCP/IP. */
+int usbip_recv(struct socket *sock, void *buf, int size)
+{
+	int result;
+	struct kvec iov = {.iov_base = buf, .iov_len = size};
+	struct msghdr msg = {.msg_flags = MSG_NOSIGNAL};
+	int total = 0;
+
+	if (!sock || !buf || !size)
+		return -EINVAL;
+
+	iov_iter_kvec(&msg.msg_iter, READ|ITER_KVEC, &iov, 1, size);
+
+	usbip_dbg_xmit("enter\n");
+
+	do {
+		sock->sk->sk_allocation = GFP_NOIO;
+
+		result = sock_recvmsg(sock, &msg, MSG_WAITALL);
+		if (result <= 0)
+			goto err;
+
+		total += result;
+	} while (msg_data_left(&msg));
+
+	if (usbip_dbg_flag_xmit) {
+		if (!in_interrupt())
+			pr_debug("%-10s:", current->comm);
+		else
+			pr_debug("interrupt  :");
+
+		pr_debug("receiving....\n");
+		usbip_dump_buffer(buf, size);
+		pr_debug("received, osize %d ret %d size %zd total %d\n",
+			 size, result, msg_data_left(&msg), total);
+	}
+
+	return total;
+
+err:
+	return result;
+}
+EXPORT_SYMBOL_GPL(usbip_recv);
+
+/* there may be more cases to tweak the flags. */
+static unsigned int tweak_transfer_flags(unsigned int flags)
+{
+	flags &= ~URB_NO_TRANSFER_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) {
+		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  {
+		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) {
+		rpdu->status		= urb->status;
+		rpdu->actual_length	= urb->actual_length;
+		rpdu->start_frame	= urb->start_frame;
+		rpdu->number_of_packets = urb->number_of_packets;
+		rpdu->error_count	= urb->error_count;
+	} else {
+		urb->status		= rpdu->status;
+		urb->actual_length	= rpdu->actual_length;
+		urb->start_frame	= rpdu->start_frame;
+		urb->number_of_packets = rpdu->number_of_packets;
+		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:
+		/* NOT REACHED */
+		pr_err("unknown command\n");
+		break;
+	}
+}
+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->number_of_packets);
+		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->number_of_packets);
+		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:
+		/* NOT REACHED */
+		pr_err("unknown command\n");
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(usbip_header_correct_endian);
+
+static void usbip_iso_packet_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 */
+struct usbip_iso_packet_descriptor*
+usbip_alloc_iso_desc_pdu(struct urb *urb, ssize_t *bufflen)
+{
+	struct usbip_iso_packet_descriptor *iso;
+	int np = urb->number_of_packets;
+	ssize_t size = np * sizeof(*iso);
+	int i;
+
+	iso = kzalloc(size, GFP_KERNEL);
+	if (!iso)
+		return NULL;
+
+	for (i = 0; i < np; i++) {
+		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 1);
+		usbip_iso_packet_correct_endian(&iso[i], 1);
+	}
+
+	*bufflen = size;
+
+	return iso;
+}
+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;
+	int total_length = 0;
+
+	if (!usb_pipeisoc(urb->pipe))
+		return 0;
+
+	/* my Bluetooth dongle gets ISO URBs which are np = 0 */
+	if (np == 0)
+		return 0;
+
+	buff = kzalloc(size, GFP_KERNEL);
+	if (!buff)
+		return -ENOMEM;
+
+	ret = usbip_recv(ud->tcp_socket, buff, size);
+	if (ret != size) {
+		dev_err(&urb->dev->dev, "recv iso_frame_descriptor, %d\n",
+			ret);
+		kfree(buff);
+
+		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
+			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
+		else
+			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
+
+		return -EPIPE;
+	}
+
+	iso = (struct usbip_iso_packet_descriptor *) buff;
+	for (i = 0; i < np; i++) {
+		usbip_iso_packet_correct_endian(&iso[i], 0);
+		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 0);
+		total_length += urb->iso_frame_desc[i].actual_length;
+	}
+
+	kfree(buff);
+
+	if (total_length != urb->actual_length) {
+		dev_err(&urb->dev->dev,
+			"total length of iso packets %d not equal to actual length of buffer %d\n",
+			total_length, urb->actual_length);
+
+		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
+			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_iso);
+
+/*
+ * This functions restores the padding which was removed for optimizing
+ * the bandwidth during transfer over tcp/ip
+ *
+ * buffer and iso packets need to be stored and be in propeper endian in urb
+ * before calling this function
+ */
+void usbip_pad_iso(struct usbip_device *ud, struct urb *urb)
+{
+	int np = urb->number_of_packets;
+	int i;
+	int actualoffset = urb->actual_length;
+
+	if (!usb_pipeisoc(urb->pipe))
+		return;
+
+	/* if no packets or length of data is 0, then nothing to unpack */
+	if (np == 0 || urb->actual_length == 0)
+		return;
+
+	/*
+	 * if actual_length is transfer_buffer_length then no padding is
+	 * present.
+	 */
+	if (urb->actual_length == urb->transfer_buffer_length)
+		return;
+
+	/*
+	 * loop over all packets from last to first (to prevent overwriting
+	 * memory when padding) and move them into the proper place
+	 */
+	for (i = np-1; i > 0; i--) {
+		actualoffset -= urb->iso_frame_desc[i].actual_length;
+		memmove(urb->transfer_buffer + urb->iso_frame_desc[i].offset,
+			urb->transfer_buffer + actualoffset,
+			urb->iso_frame_desc[i].actual_length);
+	}
+}
+EXPORT_SYMBOL_GPL(usbip_pad_iso);
+
+/* some members of urb must be substituted before. */
+int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
+{
+	struct scatterlist *sg;
+	int ret = 0;
+	int recv;
+	int size;
+	int copy;
+	int i;
+
+	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
+		/* the direction of urb must be OUT. */
+		if (usb_pipein(urb->pipe))
+			return 0;
+
+		size = urb->transfer_buffer_length;
+	} else {
+		/* 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;
+
+	if (size > urb->transfer_buffer_length)
+		/* should not happen, probably malicious packet */
+		goto error;
+
+	if (urb->num_sgs) {
+		copy = size;
+		for_each_sg(urb->sg, sg, urb->num_sgs, i) {
+			int recv_size;
+
+			if (copy < sg->length)
+				recv_size = copy;
+			else
+				recv_size = sg->length;
+
+			recv = usbip_recv(ud->tcp_socket, sg_virt(sg),
+						recv_size);
+
+			if (recv != recv_size)
+				goto error;
+
+			copy -= recv;
+			ret += recv;
+
+			if (!copy)
+				break;
+		}
+
+		if (ret != size)
+			goto error;
+	} else {
+		ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
+		if (ret != size)
+			goto error;
+	}
+
+	return ret;
+
+error:
+	dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
+	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
+		usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
+	else
+		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
+
+	return -EPIPE;
+}
+EXPORT_SYMBOL_GPL(usbip_recv_xbuff);
+
+static int __init usbip_core_init(void)
+{
+	int ret;
+
+	ret = usbip_init_eh();
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void __exit usbip_core_exit(void)
+{
+	usbip_finish_eh();
+	return;
+}
+
+module_init(usbip_core_init);
+module_exit(usbip_core_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");