xref: /openbmc/linux/drivers/usb/usbip/usbip_common.c (revision c127f98ba9aba1818a6ca3a1da5a24653a10d966)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2003-2008 Takahiro Hirofuchi
4  * Copyright (C) 2015-2016 Samsung Electronics
5  *               Krzysztof Opasiak <k.opasiak@samsung.com>
6  */
7 
8 #include <asm/byteorder.h>
9 #include <linux/file.h>
10 #include <linux/fs.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/stat.h>
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <net/sock.h>
17 
18 #include "usbip_common.h"
19 
20 #define DRIVER_AUTHOR "Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>"
21 #define DRIVER_DESC "USB/IP Core"
22 
23 #ifdef CONFIG_USBIP_DEBUG
24 unsigned long usbip_debug_flag = 0xffffffff;
25 #else
26 unsigned long usbip_debug_flag;
27 #endif
28 EXPORT_SYMBOL_GPL(usbip_debug_flag);
29 module_param(usbip_debug_flag, ulong, S_IRUGO|S_IWUSR);
30 MODULE_PARM_DESC(usbip_debug_flag, "debug flags (defined in usbip_common.h)");
31 
32 /* FIXME */
33 struct device_attribute dev_attr_usbip_debug;
34 EXPORT_SYMBOL_GPL(dev_attr_usbip_debug);
35 
36 static ssize_t usbip_debug_show(struct device *dev,
37 				struct device_attribute *attr, char *buf)
38 {
39 	return sprintf(buf, "%lx\n", usbip_debug_flag);
40 }
41 
42 static ssize_t usbip_debug_store(struct device *dev,
43 				 struct device_attribute *attr, const char *buf,
44 				 size_t count)
45 {
46 	if (sscanf(buf, "%lx", &usbip_debug_flag) != 1)
47 		return -EINVAL;
48 	return count;
49 }
50 DEVICE_ATTR_RW(usbip_debug);
51 
52 static void usbip_dump_buffer(char *buff, int bufflen)
53 {
54 	print_hex_dump(KERN_DEBUG, "usbip-core", DUMP_PREFIX_OFFSET, 16, 4,
55 		       buff, bufflen, false);
56 }
57 
58 static void usbip_dump_pipe(unsigned int p)
59 {
60 	unsigned char type = usb_pipetype(p);
61 	unsigned char ep   = usb_pipeendpoint(p);
62 	unsigned char dev  = usb_pipedevice(p);
63 	unsigned char dir  = usb_pipein(p);
64 
65 	pr_debug("dev(%d) ep(%d) [%s] ", dev, ep, dir ? "IN" : "OUT");
66 
67 	switch (type) {
68 	case PIPE_ISOCHRONOUS:
69 		pr_debug("ISO\n");
70 		break;
71 	case PIPE_INTERRUPT:
72 		pr_debug("INT\n");
73 		break;
74 	case PIPE_CONTROL:
75 		pr_debug("CTRL\n");
76 		break;
77 	case PIPE_BULK:
78 		pr_debug("BULK\n");
79 		break;
80 	default:
81 		pr_debug("ERR\n");
82 		break;
83 	}
84 }
85 
86 static void usbip_dump_usb_device(struct usb_device *udev)
87 {
88 	struct device *dev = &udev->dev;
89 	int i;
90 
91 	dev_dbg(dev, "       devnum(%d) devpath(%s) usb speed(%s)",
92 		udev->devnum, udev->devpath, usb_speed_string(udev->speed));
93 
94 	pr_debug("tt %p, ttport %d\n", udev->tt, udev->ttport);
95 
96 	dev_dbg(dev, "                    ");
97 	for (i = 0; i < 16; i++)
98 		pr_debug(" %2u", i);
99 	pr_debug("\n");
100 
101 	dev_dbg(dev, "       toggle0(IN) :");
102 	for (i = 0; i < 16; i++)
103 		pr_debug(" %2u", (udev->toggle[0] & (1 << i)) ? 1 : 0);
104 	pr_debug("\n");
105 
106 	dev_dbg(dev, "       toggle1(OUT):");
107 	for (i = 0; i < 16; i++)
108 		pr_debug(" %2u", (udev->toggle[1] & (1 << i)) ? 1 : 0);
109 	pr_debug("\n");
110 
111 	dev_dbg(dev, "       epmaxp_in   :");
112 	for (i = 0; i < 16; i++) {
113 		if (udev->ep_in[i])
114 			pr_debug(" %2u",
115 			    le16_to_cpu(udev->ep_in[i]->desc.wMaxPacketSize));
116 	}
117 	pr_debug("\n");
118 
119 	dev_dbg(dev, "       epmaxp_out  :");
120 	for (i = 0; i < 16; i++) {
121 		if (udev->ep_out[i])
122 			pr_debug(" %2u",
123 			    le16_to_cpu(udev->ep_out[i]->desc.wMaxPacketSize));
124 	}
125 	pr_debug("\n");
126 
127 	dev_dbg(dev, "parent %p, bus %p\n", udev->parent, udev->bus);
128 
129 	dev_dbg(dev,
130 		"descriptor %p, config %p, actconfig %p, rawdescriptors %p\n",
131 		&udev->descriptor, udev->config,
132 		udev->actconfig, udev->rawdescriptors);
133 
134 	dev_dbg(dev, "have_langid %d, string_langid %d\n",
135 		udev->have_langid, udev->string_langid);
136 
137 	dev_dbg(dev, "maxchild %d\n", udev->maxchild);
138 }
139 
140 static void usbip_dump_request_type(__u8 rt)
141 {
142 	switch (rt & USB_RECIP_MASK) {
143 	case USB_RECIP_DEVICE:
144 		pr_debug("DEVICE");
145 		break;
146 	case USB_RECIP_INTERFACE:
147 		pr_debug("INTERF");
148 		break;
149 	case USB_RECIP_ENDPOINT:
150 		pr_debug("ENDPOI");
151 		break;
152 	case USB_RECIP_OTHER:
153 		pr_debug("OTHER ");
154 		break;
155 	default:
156 		pr_debug("------");
157 		break;
158 	}
159 }
160 
161 static void usbip_dump_usb_ctrlrequest(struct usb_ctrlrequest *cmd)
162 {
163 	if (!cmd) {
164 		pr_debug("       : null pointer\n");
165 		return;
166 	}
167 
168 	pr_debug("       ");
169 	pr_debug("bRequestType(%02X) bRequest(%02X) wValue(%04X) wIndex(%04X) wLength(%04X) ",
170 		 cmd->bRequestType, cmd->bRequest,
171 		 cmd->wValue, cmd->wIndex, cmd->wLength);
172 	pr_debug("\n       ");
173 
174 	if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
175 		pr_debug("STANDARD ");
176 		switch (cmd->bRequest) {
177 		case USB_REQ_GET_STATUS:
178 			pr_debug("GET_STATUS\n");
179 			break;
180 		case USB_REQ_CLEAR_FEATURE:
181 			pr_debug("CLEAR_FEAT\n");
182 			break;
183 		case USB_REQ_SET_FEATURE:
184 			pr_debug("SET_FEAT\n");
185 			break;
186 		case USB_REQ_SET_ADDRESS:
187 			pr_debug("SET_ADDRRS\n");
188 			break;
189 		case USB_REQ_GET_DESCRIPTOR:
190 			pr_debug("GET_DESCRI\n");
191 			break;
192 		case USB_REQ_SET_DESCRIPTOR:
193 			pr_debug("SET_DESCRI\n");
194 			break;
195 		case USB_REQ_GET_CONFIGURATION:
196 			pr_debug("GET_CONFIG\n");
197 			break;
198 		case USB_REQ_SET_CONFIGURATION:
199 			pr_debug("SET_CONFIG\n");
200 			break;
201 		case USB_REQ_GET_INTERFACE:
202 			pr_debug("GET_INTERF\n");
203 			break;
204 		case USB_REQ_SET_INTERFACE:
205 			pr_debug("SET_INTERF\n");
206 			break;
207 		case USB_REQ_SYNCH_FRAME:
208 			pr_debug("SYNC_FRAME\n");
209 			break;
210 		default:
211 			pr_debug("REQ(%02X)\n", cmd->bRequest);
212 			break;
213 		}
214 		usbip_dump_request_type(cmd->bRequestType);
215 	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS) {
216 		pr_debug("CLASS\n");
217 	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_VENDOR) {
218 		pr_debug("VENDOR\n");
219 	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_RESERVED) {
220 		pr_debug("RESERVED\n");
221 	}
222 }
223 
224 void usbip_dump_urb(struct urb *urb)
225 {
226 	struct device *dev;
227 
228 	if (!urb) {
229 		pr_debug("urb: null pointer!!\n");
230 		return;
231 	}
232 
233 	if (!urb->dev) {
234 		pr_debug("urb->dev: null pointer!!\n");
235 		return;
236 	}
237 
238 	dev = &urb->dev->dev;
239 
240 	dev_dbg(dev, "   urb                   :%p\n", urb);
241 	dev_dbg(dev, "   dev                   :%p\n", urb->dev);
242 
243 	usbip_dump_usb_device(urb->dev);
244 
245 	dev_dbg(dev, "   pipe                  :%08x ", urb->pipe);
246 
247 	usbip_dump_pipe(urb->pipe);
248 
249 	dev_dbg(dev, "   status                :%d\n", urb->status);
250 	dev_dbg(dev, "   transfer_flags        :%08X\n", urb->transfer_flags);
251 	dev_dbg(dev, "   transfer_buffer       :%p\n", urb->transfer_buffer);
252 	dev_dbg(dev, "   transfer_buffer_length:%d\n",
253 						urb->transfer_buffer_length);
254 	dev_dbg(dev, "   actual_length         :%d\n", urb->actual_length);
255 	dev_dbg(dev, "   setup_packet          :%p\n", urb->setup_packet);
256 
257 	if (urb->setup_packet && usb_pipetype(urb->pipe) == PIPE_CONTROL)
258 		usbip_dump_usb_ctrlrequest(
259 			(struct usb_ctrlrequest *)urb->setup_packet);
260 
261 	dev_dbg(dev, "   start_frame           :%d\n", urb->start_frame);
262 	dev_dbg(dev, "   number_of_packets     :%d\n", urb->number_of_packets);
263 	dev_dbg(dev, "   interval              :%d\n", urb->interval);
264 	dev_dbg(dev, "   error_count           :%d\n", urb->error_count);
265 	dev_dbg(dev, "   context               :%p\n", urb->context);
266 	dev_dbg(dev, "   complete              :%p\n", urb->complete);
267 }
268 EXPORT_SYMBOL_GPL(usbip_dump_urb);
269 
270 void usbip_dump_header(struct usbip_header *pdu)
271 {
272 	pr_debug("BASE: cmd %u seq %u devid %u dir %u ep %u\n",
273 		 pdu->base.command,
274 		 pdu->base.seqnum,
275 		 pdu->base.devid,
276 		 pdu->base.direction,
277 		 pdu->base.ep);
278 
279 	switch (pdu->base.command) {
280 	case USBIP_CMD_SUBMIT:
281 		pr_debug("USBIP_CMD_SUBMIT: x_flags %u x_len %u sf %u #p %d iv %d\n",
282 			 pdu->u.cmd_submit.transfer_flags,
283 			 pdu->u.cmd_submit.transfer_buffer_length,
284 			 pdu->u.cmd_submit.start_frame,
285 			 pdu->u.cmd_submit.number_of_packets,
286 			 pdu->u.cmd_submit.interval);
287 		break;
288 	case USBIP_CMD_UNLINK:
289 		pr_debug("USBIP_CMD_UNLINK: seq %u\n",
290 			 pdu->u.cmd_unlink.seqnum);
291 		break;
292 	case USBIP_RET_SUBMIT:
293 		pr_debug("USBIP_RET_SUBMIT: st %d al %u sf %d #p %d ec %d\n",
294 			 pdu->u.ret_submit.status,
295 			 pdu->u.ret_submit.actual_length,
296 			 pdu->u.ret_submit.start_frame,
297 			 pdu->u.ret_submit.number_of_packets,
298 			 pdu->u.ret_submit.error_count);
299 		break;
300 	case USBIP_RET_UNLINK:
301 		pr_debug("USBIP_RET_UNLINK: status %d\n",
302 			 pdu->u.ret_unlink.status);
303 		break;
304 	default:
305 		/* NOT REACHED */
306 		pr_err("unknown command\n");
307 		break;
308 	}
309 }
310 EXPORT_SYMBOL_GPL(usbip_dump_header);
311 
312 /* Receive data over TCP/IP. */
313 int usbip_recv(struct socket *sock, void *buf, int size)
314 {
315 	int result;
316 	struct kvec iov = {.iov_base = buf, .iov_len = size};
317 	struct msghdr msg = {.msg_flags = MSG_NOSIGNAL};
318 	int total = 0;
319 
320 	if (!sock || !buf || !size)
321 		return -EINVAL;
322 
323 	iov_iter_kvec(&msg.msg_iter, READ|ITER_KVEC, &iov, 1, size);
324 
325 	usbip_dbg_xmit("enter\n");
326 
327 	do {
328 		msg_data_left(&msg);
329 		sock->sk->sk_allocation = GFP_NOIO;
330 
331 		result = sock_recvmsg(sock, &msg, MSG_WAITALL);
332 		if (result <= 0)
333 			goto err;
334 
335 		total += result;
336 	} while (msg_data_left(&msg));
337 
338 	if (usbip_dbg_flag_xmit) {
339 		if (!in_interrupt())
340 			pr_debug("%-10s:", current->comm);
341 		else
342 			pr_debug("interrupt  :");
343 
344 		pr_debug("receiving....\n");
345 		usbip_dump_buffer(buf, size);
346 		pr_debug("received, osize %d ret %d size %zd total %d\n",
347 			 size, result, msg_data_left(&msg), total);
348 	}
349 
350 	return total;
351 
352 err:
353 	return result;
354 }
355 EXPORT_SYMBOL_GPL(usbip_recv);
356 
357 /* there may be more cases to tweak the flags. */
358 static unsigned int tweak_transfer_flags(unsigned int flags)
359 {
360 	flags &= ~URB_NO_TRANSFER_DMA_MAP;
361 	return flags;
362 }
363 
364 static void usbip_pack_cmd_submit(struct usbip_header *pdu, struct urb *urb,
365 				  int pack)
366 {
367 	struct usbip_header_cmd_submit *spdu = &pdu->u.cmd_submit;
368 
369 	/*
370 	 * Some members are not still implemented in usbip. I hope this issue
371 	 * will be discussed when usbip is ported to other operating systems.
372 	 */
373 	if (pack) {
374 		spdu->transfer_flags =
375 			tweak_transfer_flags(urb->transfer_flags);
376 		spdu->transfer_buffer_length	= urb->transfer_buffer_length;
377 		spdu->start_frame		= urb->start_frame;
378 		spdu->number_of_packets		= urb->number_of_packets;
379 		spdu->interval			= urb->interval;
380 	} else  {
381 		urb->transfer_flags         = spdu->transfer_flags;
382 		urb->transfer_buffer_length = spdu->transfer_buffer_length;
383 		urb->start_frame            = spdu->start_frame;
384 		urb->number_of_packets      = spdu->number_of_packets;
385 		urb->interval               = spdu->interval;
386 	}
387 }
388 
389 static void usbip_pack_ret_submit(struct usbip_header *pdu, struct urb *urb,
390 				  int pack)
391 {
392 	struct usbip_header_ret_submit *rpdu = &pdu->u.ret_submit;
393 
394 	if (pack) {
395 		rpdu->status		= urb->status;
396 		rpdu->actual_length	= urb->actual_length;
397 		rpdu->start_frame	= urb->start_frame;
398 		rpdu->number_of_packets = urb->number_of_packets;
399 		rpdu->error_count	= urb->error_count;
400 	} else {
401 		urb->status		= rpdu->status;
402 		urb->actual_length	= rpdu->actual_length;
403 		urb->start_frame	= rpdu->start_frame;
404 		urb->number_of_packets = rpdu->number_of_packets;
405 		urb->error_count	= rpdu->error_count;
406 	}
407 }
408 
409 void usbip_pack_pdu(struct usbip_header *pdu, struct urb *urb, int cmd,
410 		    int pack)
411 {
412 	switch (cmd) {
413 	case USBIP_CMD_SUBMIT:
414 		usbip_pack_cmd_submit(pdu, urb, pack);
415 		break;
416 	case USBIP_RET_SUBMIT:
417 		usbip_pack_ret_submit(pdu, urb, pack);
418 		break;
419 	default:
420 		/* NOT REACHED */
421 		pr_err("unknown command\n");
422 		break;
423 	}
424 }
425 EXPORT_SYMBOL_GPL(usbip_pack_pdu);
426 
427 static void correct_endian_basic(struct usbip_header_basic *base, int send)
428 {
429 	if (send) {
430 		base->command	= cpu_to_be32(base->command);
431 		base->seqnum	= cpu_to_be32(base->seqnum);
432 		base->devid	= cpu_to_be32(base->devid);
433 		base->direction	= cpu_to_be32(base->direction);
434 		base->ep	= cpu_to_be32(base->ep);
435 	} else {
436 		base->command	= be32_to_cpu(base->command);
437 		base->seqnum	= be32_to_cpu(base->seqnum);
438 		base->devid	= be32_to_cpu(base->devid);
439 		base->direction	= be32_to_cpu(base->direction);
440 		base->ep	= be32_to_cpu(base->ep);
441 	}
442 }
443 
444 static void correct_endian_cmd_submit(struct usbip_header_cmd_submit *pdu,
445 				      int send)
446 {
447 	if (send) {
448 		pdu->transfer_flags = cpu_to_be32(pdu->transfer_flags);
449 
450 		cpu_to_be32s(&pdu->transfer_buffer_length);
451 		cpu_to_be32s(&pdu->start_frame);
452 		cpu_to_be32s(&pdu->number_of_packets);
453 		cpu_to_be32s(&pdu->interval);
454 	} else {
455 		pdu->transfer_flags = be32_to_cpu(pdu->transfer_flags);
456 
457 		be32_to_cpus(&pdu->transfer_buffer_length);
458 		be32_to_cpus(&pdu->start_frame);
459 		be32_to_cpus(&pdu->number_of_packets);
460 		be32_to_cpus(&pdu->interval);
461 	}
462 }
463 
464 static void correct_endian_ret_submit(struct usbip_header_ret_submit *pdu,
465 				      int send)
466 {
467 	if (send) {
468 		cpu_to_be32s(&pdu->status);
469 		cpu_to_be32s(&pdu->actual_length);
470 		cpu_to_be32s(&pdu->start_frame);
471 		cpu_to_be32s(&pdu->number_of_packets);
472 		cpu_to_be32s(&pdu->error_count);
473 	} else {
474 		be32_to_cpus(&pdu->status);
475 		be32_to_cpus(&pdu->actual_length);
476 		be32_to_cpus(&pdu->start_frame);
477 		be32_to_cpus(&pdu->number_of_packets);
478 		be32_to_cpus(&pdu->error_count);
479 	}
480 }
481 
482 static void correct_endian_cmd_unlink(struct usbip_header_cmd_unlink *pdu,
483 				      int send)
484 {
485 	if (send)
486 		pdu->seqnum = cpu_to_be32(pdu->seqnum);
487 	else
488 		pdu->seqnum = be32_to_cpu(pdu->seqnum);
489 }
490 
491 static void correct_endian_ret_unlink(struct usbip_header_ret_unlink *pdu,
492 				      int send)
493 {
494 	if (send)
495 		cpu_to_be32s(&pdu->status);
496 	else
497 		be32_to_cpus(&pdu->status);
498 }
499 
500 void usbip_header_correct_endian(struct usbip_header *pdu, int send)
501 {
502 	__u32 cmd = 0;
503 
504 	if (send)
505 		cmd = pdu->base.command;
506 
507 	correct_endian_basic(&pdu->base, send);
508 
509 	if (!send)
510 		cmd = pdu->base.command;
511 
512 	switch (cmd) {
513 	case USBIP_CMD_SUBMIT:
514 		correct_endian_cmd_submit(&pdu->u.cmd_submit, send);
515 		break;
516 	case USBIP_RET_SUBMIT:
517 		correct_endian_ret_submit(&pdu->u.ret_submit, send);
518 		break;
519 	case USBIP_CMD_UNLINK:
520 		correct_endian_cmd_unlink(&pdu->u.cmd_unlink, send);
521 		break;
522 	case USBIP_RET_UNLINK:
523 		correct_endian_ret_unlink(&pdu->u.ret_unlink, send);
524 		break;
525 	default:
526 		/* NOT REACHED */
527 		pr_err("unknown command\n");
528 		break;
529 	}
530 }
531 EXPORT_SYMBOL_GPL(usbip_header_correct_endian);
532 
533 static void usbip_iso_packet_correct_endian(
534 		struct usbip_iso_packet_descriptor *iso, int send)
535 {
536 	/* does not need all members. but copy all simply. */
537 	if (send) {
538 		iso->offset	= cpu_to_be32(iso->offset);
539 		iso->length	= cpu_to_be32(iso->length);
540 		iso->status	= cpu_to_be32(iso->status);
541 		iso->actual_length = cpu_to_be32(iso->actual_length);
542 	} else {
543 		iso->offset	= be32_to_cpu(iso->offset);
544 		iso->length	= be32_to_cpu(iso->length);
545 		iso->status	= be32_to_cpu(iso->status);
546 		iso->actual_length = be32_to_cpu(iso->actual_length);
547 	}
548 }
549 
550 static void usbip_pack_iso(struct usbip_iso_packet_descriptor *iso,
551 			   struct usb_iso_packet_descriptor *uiso, int pack)
552 {
553 	if (pack) {
554 		iso->offset		= uiso->offset;
555 		iso->length		= uiso->length;
556 		iso->status		= uiso->status;
557 		iso->actual_length	= uiso->actual_length;
558 	} else {
559 		uiso->offset		= iso->offset;
560 		uiso->length		= iso->length;
561 		uiso->status		= iso->status;
562 		uiso->actual_length	= iso->actual_length;
563 	}
564 }
565 
566 /* must free buffer */
567 struct usbip_iso_packet_descriptor*
568 usbip_alloc_iso_desc_pdu(struct urb *urb, ssize_t *bufflen)
569 {
570 	struct usbip_iso_packet_descriptor *iso;
571 	int np = urb->number_of_packets;
572 	ssize_t size = np * sizeof(*iso);
573 	int i;
574 
575 	iso = kzalloc(size, GFP_KERNEL);
576 	if (!iso)
577 		return NULL;
578 
579 	for (i = 0; i < np; i++) {
580 		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 1);
581 		usbip_iso_packet_correct_endian(&iso[i], 1);
582 	}
583 
584 	*bufflen = size;
585 
586 	return iso;
587 }
588 EXPORT_SYMBOL_GPL(usbip_alloc_iso_desc_pdu);
589 
590 /* some members of urb must be substituted before. */
591 int usbip_recv_iso(struct usbip_device *ud, struct urb *urb)
592 {
593 	void *buff;
594 	struct usbip_iso_packet_descriptor *iso;
595 	int np = urb->number_of_packets;
596 	int size = np * sizeof(*iso);
597 	int i;
598 	int ret;
599 	int total_length = 0;
600 
601 	if (!usb_pipeisoc(urb->pipe))
602 		return 0;
603 
604 	/* my Bluetooth dongle gets ISO URBs which are np = 0 */
605 	if (np == 0)
606 		return 0;
607 
608 	buff = kzalloc(size, GFP_KERNEL);
609 	if (!buff)
610 		return -ENOMEM;
611 
612 	ret = usbip_recv(ud->tcp_socket, buff, size);
613 	if (ret != size) {
614 		dev_err(&urb->dev->dev, "recv iso_frame_descriptor, %d\n",
615 			ret);
616 		kfree(buff);
617 
618 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
619 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
620 		else
621 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
622 
623 		return -EPIPE;
624 	}
625 
626 	iso = (struct usbip_iso_packet_descriptor *) buff;
627 	for (i = 0; i < np; i++) {
628 		usbip_iso_packet_correct_endian(&iso[i], 0);
629 		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 0);
630 		total_length += urb->iso_frame_desc[i].actual_length;
631 	}
632 
633 	kfree(buff);
634 
635 	if (total_length != urb->actual_length) {
636 		dev_err(&urb->dev->dev,
637 			"total length of iso packets %d not equal to actual length of buffer %d\n",
638 			total_length, urb->actual_length);
639 
640 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
641 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
642 		else
643 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
644 
645 		return -EPIPE;
646 	}
647 
648 	return ret;
649 }
650 EXPORT_SYMBOL_GPL(usbip_recv_iso);
651 
652 /*
653  * This functions restores the padding which was removed for optimizing
654  * the bandwidth during transfer over tcp/ip
655  *
656  * buffer and iso packets need to be stored and be in propeper endian in urb
657  * before calling this function
658  */
659 void usbip_pad_iso(struct usbip_device *ud, struct urb *urb)
660 {
661 	int np = urb->number_of_packets;
662 	int i;
663 	int actualoffset = urb->actual_length;
664 
665 	if (!usb_pipeisoc(urb->pipe))
666 		return;
667 
668 	/* if no packets or length of data is 0, then nothing to unpack */
669 	if (np == 0 || urb->actual_length == 0)
670 		return;
671 
672 	/*
673 	 * if actual_length is transfer_buffer_length then no padding is
674 	 * present.
675 	 */
676 	if (urb->actual_length == urb->transfer_buffer_length)
677 		return;
678 
679 	/*
680 	 * loop over all packets from last to first (to prevent overwriting
681 	 * memory when padding) and move them into the proper place
682 	 */
683 	for (i = np-1; i > 0; i--) {
684 		actualoffset -= urb->iso_frame_desc[i].actual_length;
685 		memmove(urb->transfer_buffer + urb->iso_frame_desc[i].offset,
686 			urb->transfer_buffer + actualoffset,
687 			urb->iso_frame_desc[i].actual_length);
688 	}
689 }
690 EXPORT_SYMBOL_GPL(usbip_pad_iso);
691 
692 /* some members of urb must be substituted before. */
693 int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
694 {
695 	int ret;
696 	int size;
697 
698 	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
699 		/* the direction of urb must be OUT. */
700 		if (usb_pipein(urb->pipe))
701 			return 0;
702 
703 		size = urb->transfer_buffer_length;
704 	} else {
705 		/* the direction of urb must be IN. */
706 		if (usb_pipeout(urb->pipe))
707 			return 0;
708 
709 		size = urb->actual_length;
710 	}
711 
712 	/* no need to recv xbuff */
713 	if (!(size > 0))
714 		return 0;
715 
716 	if (size > urb->transfer_buffer_length) {
717 		/* should not happen, probably malicious packet */
718 		if (ud->side == USBIP_STUB) {
719 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
720 			return 0;
721 		} else {
722 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
723 			return -EPIPE;
724 		}
725 	}
726 
727 	ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
728 	if (ret != size) {
729 		dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
730 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
731 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
732 		} else {
733 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
734 			return -EPIPE;
735 		}
736 	}
737 
738 	return ret;
739 }
740 EXPORT_SYMBOL_GPL(usbip_recv_xbuff);
741 
742 static int __init usbip_core_init(void)
743 {
744 	int ret;
745 
746 	ret = usbip_init_eh();
747 	if (ret)
748 		return ret;
749 
750 	return 0;
751 }
752 
753 static void __exit usbip_core_exit(void)
754 {
755 	usbip_finish_eh();
756 	return;
757 }
758 
759 module_init(usbip_core_init);
760 module_exit(usbip_core_exit);
761 
762 MODULE_AUTHOR(DRIVER_AUTHOR);
763 MODULE_DESCRIPTION(DRIVER_DESC);
764 MODULE_LICENSE("GPL");
765