xref: /linux/drivers/usb/usbip/usbip_common.c (revision 140eb5227767c6754742020a16d2691222b9c19b)
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 hub ttport %d\n", 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 %s, bus %s\n", dev_name(&udev->parent->dev),
128 		udev->bus->bus_name);
129 
130 	dev_dbg(dev, "have_langid %d, string_langid %d\n",
131 		udev->have_langid, udev->string_langid);
132 
133 	dev_dbg(dev, "maxchild %d\n", udev->maxchild);
134 }
135 
136 static void usbip_dump_request_type(__u8 rt)
137 {
138 	switch (rt & USB_RECIP_MASK) {
139 	case USB_RECIP_DEVICE:
140 		pr_debug("DEVICE");
141 		break;
142 	case USB_RECIP_INTERFACE:
143 		pr_debug("INTERF");
144 		break;
145 	case USB_RECIP_ENDPOINT:
146 		pr_debug("ENDPOI");
147 		break;
148 	case USB_RECIP_OTHER:
149 		pr_debug("OTHER ");
150 		break;
151 	default:
152 		pr_debug("------");
153 		break;
154 	}
155 }
156 
157 static void usbip_dump_usb_ctrlrequest(struct usb_ctrlrequest *cmd)
158 {
159 	if (!cmd) {
160 		pr_debug("       : null pointer\n");
161 		return;
162 	}
163 
164 	pr_debug("       ");
165 	pr_debug("bRequestType(%02X) bRequest(%02X) wValue(%04X) wIndex(%04X) wLength(%04X) ",
166 		 cmd->bRequestType, cmd->bRequest,
167 		 cmd->wValue, cmd->wIndex, cmd->wLength);
168 	pr_debug("\n       ");
169 
170 	if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
171 		pr_debug("STANDARD ");
172 		switch (cmd->bRequest) {
173 		case USB_REQ_GET_STATUS:
174 			pr_debug("GET_STATUS\n");
175 			break;
176 		case USB_REQ_CLEAR_FEATURE:
177 			pr_debug("CLEAR_FEAT\n");
178 			break;
179 		case USB_REQ_SET_FEATURE:
180 			pr_debug("SET_FEAT\n");
181 			break;
182 		case USB_REQ_SET_ADDRESS:
183 			pr_debug("SET_ADDRRS\n");
184 			break;
185 		case USB_REQ_GET_DESCRIPTOR:
186 			pr_debug("GET_DESCRI\n");
187 			break;
188 		case USB_REQ_SET_DESCRIPTOR:
189 			pr_debug("SET_DESCRI\n");
190 			break;
191 		case USB_REQ_GET_CONFIGURATION:
192 			pr_debug("GET_CONFIG\n");
193 			break;
194 		case USB_REQ_SET_CONFIGURATION:
195 			pr_debug("SET_CONFIG\n");
196 			break;
197 		case USB_REQ_GET_INTERFACE:
198 			pr_debug("GET_INTERF\n");
199 			break;
200 		case USB_REQ_SET_INTERFACE:
201 			pr_debug("SET_INTERF\n");
202 			break;
203 		case USB_REQ_SYNCH_FRAME:
204 			pr_debug("SYNC_FRAME\n");
205 			break;
206 		default:
207 			pr_debug("REQ(%02X)\n", cmd->bRequest);
208 			break;
209 		}
210 		usbip_dump_request_type(cmd->bRequestType);
211 	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS) {
212 		pr_debug("CLASS\n");
213 	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_VENDOR) {
214 		pr_debug("VENDOR\n");
215 	} else if ((cmd->bRequestType & USB_TYPE_MASK) == USB_TYPE_RESERVED) {
216 		pr_debug("RESERVED\n");
217 	}
218 }
219 
220 void usbip_dump_urb(struct urb *urb)
221 {
222 	struct device *dev;
223 
224 	if (!urb) {
225 		pr_debug("urb: null pointer!!\n");
226 		return;
227 	}
228 
229 	if (!urb->dev) {
230 		pr_debug("urb->dev: null pointer!!\n");
231 		return;
232 	}
233 
234 	dev = &urb->dev->dev;
235 
236 	usbip_dump_usb_device(urb->dev);
237 
238 	dev_dbg(dev, "   pipe                  :%08x ", urb->pipe);
239 
240 	usbip_dump_pipe(urb->pipe);
241 
242 	dev_dbg(dev, "   status                :%d\n", urb->status);
243 	dev_dbg(dev, "   transfer_flags        :%08X\n", urb->transfer_flags);
244 	dev_dbg(dev, "   transfer_buffer_length:%d\n",
245 						urb->transfer_buffer_length);
246 	dev_dbg(dev, "   actual_length         :%d\n", urb->actual_length);
247 
248 	if (urb->setup_packet && usb_pipetype(urb->pipe) == PIPE_CONTROL)
249 		usbip_dump_usb_ctrlrequest(
250 			(struct usb_ctrlrequest *)urb->setup_packet);
251 
252 	dev_dbg(dev, "   start_frame           :%d\n", urb->start_frame);
253 	dev_dbg(dev, "   number_of_packets     :%d\n", urb->number_of_packets);
254 	dev_dbg(dev, "   interval              :%d\n", urb->interval);
255 	dev_dbg(dev, "   error_count           :%d\n", urb->error_count);
256 }
257 EXPORT_SYMBOL_GPL(usbip_dump_urb);
258 
259 void usbip_dump_header(struct usbip_header *pdu)
260 {
261 	pr_debug("BASE: cmd %u seq %u devid %u dir %u ep %u\n",
262 		 pdu->base.command,
263 		 pdu->base.seqnum,
264 		 pdu->base.devid,
265 		 pdu->base.direction,
266 		 pdu->base.ep);
267 
268 	switch (pdu->base.command) {
269 	case USBIP_CMD_SUBMIT:
270 		pr_debug("USBIP_CMD_SUBMIT: x_flags %u x_len %u sf %u #p %d iv %d\n",
271 			 pdu->u.cmd_submit.transfer_flags,
272 			 pdu->u.cmd_submit.transfer_buffer_length,
273 			 pdu->u.cmd_submit.start_frame,
274 			 pdu->u.cmd_submit.number_of_packets,
275 			 pdu->u.cmd_submit.interval);
276 		break;
277 	case USBIP_CMD_UNLINK:
278 		pr_debug("USBIP_CMD_UNLINK: seq %u\n",
279 			 pdu->u.cmd_unlink.seqnum);
280 		break;
281 	case USBIP_RET_SUBMIT:
282 		pr_debug("USBIP_RET_SUBMIT: st %d al %u sf %d #p %d ec %d\n",
283 			 pdu->u.ret_submit.status,
284 			 pdu->u.ret_submit.actual_length,
285 			 pdu->u.ret_submit.start_frame,
286 			 pdu->u.ret_submit.number_of_packets,
287 			 pdu->u.ret_submit.error_count);
288 		break;
289 	case USBIP_RET_UNLINK:
290 		pr_debug("USBIP_RET_UNLINK: status %d\n",
291 			 pdu->u.ret_unlink.status);
292 		break;
293 	default:
294 		/* NOT REACHED */
295 		pr_err("unknown command\n");
296 		break;
297 	}
298 }
299 EXPORT_SYMBOL_GPL(usbip_dump_header);
300 
301 /* Receive data over TCP/IP. */
302 int usbip_recv(struct socket *sock, void *buf, int size)
303 {
304 	int result;
305 	struct kvec iov = {.iov_base = buf, .iov_len = size};
306 	struct msghdr msg = {.msg_flags = MSG_NOSIGNAL};
307 	int total = 0;
308 
309 	if (!sock || !buf || !size)
310 		return -EINVAL;
311 
312 	iov_iter_kvec(&msg.msg_iter, READ|ITER_KVEC, &iov, 1, size);
313 
314 	usbip_dbg_xmit("enter\n");
315 
316 	do {
317 		msg_data_left(&msg);
318 		sock->sk->sk_allocation = GFP_NOIO;
319 
320 		result = sock_recvmsg(sock, &msg, MSG_WAITALL);
321 		if (result <= 0)
322 			goto err;
323 
324 		total += result;
325 	} while (msg_data_left(&msg));
326 
327 	if (usbip_dbg_flag_xmit) {
328 		if (!in_interrupt())
329 			pr_debug("%-10s:", current->comm);
330 		else
331 			pr_debug("interrupt  :");
332 
333 		pr_debug("receiving....\n");
334 		usbip_dump_buffer(buf, size);
335 		pr_debug("received, osize %d ret %d size %zd total %d\n",
336 			 size, result, msg_data_left(&msg), total);
337 	}
338 
339 	return total;
340 
341 err:
342 	return result;
343 }
344 EXPORT_SYMBOL_GPL(usbip_recv);
345 
346 /* there may be more cases to tweak the flags. */
347 static unsigned int tweak_transfer_flags(unsigned int flags)
348 {
349 	flags &= ~URB_NO_TRANSFER_DMA_MAP;
350 	return flags;
351 }
352 
353 static void usbip_pack_cmd_submit(struct usbip_header *pdu, struct urb *urb,
354 				  int pack)
355 {
356 	struct usbip_header_cmd_submit *spdu = &pdu->u.cmd_submit;
357 
358 	/*
359 	 * Some members are not still implemented in usbip. I hope this issue
360 	 * will be discussed when usbip is ported to other operating systems.
361 	 */
362 	if (pack) {
363 		spdu->transfer_flags =
364 			tweak_transfer_flags(urb->transfer_flags);
365 		spdu->transfer_buffer_length	= urb->transfer_buffer_length;
366 		spdu->start_frame		= urb->start_frame;
367 		spdu->number_of_packets		= urb->number_of_packets;
368 		spdu->interval			= urb->interval;
369 	} else  {
370 		urb->transfer_flags         = spdu->transfer_flags;
371 		urb->transfer_buffer_length = spdu->transfer_buffer_length;
372 		urb->start_frame            = spdu->start_frame;
373 		urb->number_of_packets      = spdu->number_of_packets;
374 		urb->interval               = spdu->interval;
375 	}
376 }
377 
378 static void usbip_pack_ret_submit(struct usbip_header *pdu, struct urb *urb,
379 				  int pack)
380 {
381 	struct usbip_header_ret_submit *rpdu = &pdu->u.ret_submit;
382 
383 	if (pack) {
384 		rpdu->status		= urb->status;
385 		rpdu->actual_length	= urb->actual_length;
386 		rpdu->start_frame	= urb->start_frame;
387 		rpdu->number_of_packets = urb->number_of_packets;
388 		rpdu->error_count	= urb->error_count;
389 	} else {
390 		urb->status		= rpdu->status;
391 		urb->actual_length	= rpdu->actual_length;
392 		urb->start_frame	= rpdu->start_frame;
393 		urb->number_of_packets = rpdu->number_of_packets;
394 		urb->error_count	= rpdu->error_count;
395 	}
396 }
397 
398 void usbip_pack_pdu(struct usbip_header *pdu, struct urb *urb, int cmd,
399 		    int pack)
400 {
401 	switch (cmd) {
402 	case USBIP_CMD_SUBMIT:
403 		usbip_pack_cmd_submit(pdu, urb, pack);
404 		break;
405 	case USBIP_RET_SUBMIT:
406 		usbip_pack_ret_submit(pdu, urb, pack);
407 		break;
408 	default:
409 		/* NOT REACHED */
410 		pr_err("unknown command\n");
411 		break;
412 	}
413 }
414 EXPORT_SYMBOL_GPL(usbip_pack_pdu);
415 
416 static void correct_endian_basic(struct usbip_header_basic *base, int send)
417 {
418 	if (send) {
419 		base->command	= cpu_to_be32(base->command);
420 		base->seqnum	= cpu_to_be32(base->seqnum);
421 		base->devid	= cpu_to_be32(base->devid);
422 		base->direction	= cpu_to_be32(base->direction);
423 		base->ep	= cpu_to_be32(base->ep);
424 	} else {
425 		base->command	= be32_to_cpu(base->command);
426 		base->seqnum	= be32_to_cpu(base->seqnum);
427 		base->devid	= be32_to_cpu(base->devid);
428 		base->direction	= be32_to_cpu(base->direction);
429 		base->ep	= be32_to_cpu(base->ep);
430 	}
431 }
432 
433 static void correct_endian_cmd_submit(struct usbip_header_cmd_submit *pdu,
434 				      int send)
435 {
436 	if (send) {
437 		pdu->transfer_flags = cpu_to_be32(pdu->transfer_flags);
438 
439 		cpu_to_be32s(&pdu->transfer_buffer_length);
440 		cpu_to_be32s(&pdu->start_frame);
441 		cpu_to_be32s(&pdu->number_of_packets);
442 		cpu_to_be32s(&pdu->interval);
443 	} else {
444 		pdu->transfer_flags = be32_to_cpu(pdu->transfer_flags);
445 
446 		be32_to_cpus(&pdu->transfer_buffer_length);
447 		be32_to_cpus(&pdu->start_frame);
448 		be32_to_cpus(&pdu->number_of_packets);
449 		be32_to_cpus(&pdu->interval);
450 	}
451 }
452 
453 static void correct_endian_ret_submit(struct usbip_header_ret_submit *pdu,
454 				      int send)
455 {
456 	if (send) {
457 		cpu_to_be32s(&pdu->status);
458 		cpu_to_be32s(&pdu->actual_length);
459 		cpu_to_be32s(&pdu->start_frame);
460 		cpu_to_be32s(&pdu->number_of_packets);
461 		cpu_to_be32s(&pdu->error_count);
462 	} else {
463 		be32_to_cpus(&pdu->status);
464 		be32_to_cpus(&pdu->actual_length);
465 		be32_to_cpus(&pdu->start_frame);
466 		be32_to_cpus(&pdu->number_of_packets);
467 		be32_to_cpus(&pdu->error_count);
468 	}
469 }
470 
471 static void correct_endian_cmd_unlink(struct usbip_header_cmd_unlink *pdu,
472 				      int send)
473 {
474 	if (send)
475 		pdu->seqnum = cpu_to_be32(pdu->seqnum);
476 	else
477 		pdu->seqnum = be32_to_cpu(pdu->seqnum);
478 }
479 
480 static void correct_endian_ret_unlink(struct usbip_header_ret_unlink *pdu,
481 				      int send)
482 {
483 	if (send)
484 		cpu_to_be32s(&pdu->status);
485 	else
486 		be32_to_cpus(&pdu->status);
487 }
488 
489 void usbip_header_correct_endian(struct usbip_header *pdu, int send)
490 {
491 	__u32 cmd = 0;
492 
493 	if (send)
494 		cmd = pdu->base.command;
495 
496 	correct_endian_basic(&pdu->base, send);
497 
498 	if (!send)
499 		cmd = pdu->base.command;
500 
501 	switch (cmd) {
502 	case USBIP_CMD_SUBMIT:
503 		correct_endian_cmd_submit(&pdu->u.cmd_submit, send);
504 		break;
505 	case USBIP_RET_SUBMIT:
506 		correct_endian_ret_submit(&pdu->u.ret_submit, send);
507 		break;
508 	case USBIP_CMD_UNLINK:
509 		correct_endian_cmd_unlink(&pdu->u.cmd_unlink, send);
510 		break;
511 	case USBIP_RET_UNLINK:
512 		correct_endian_ret_unlink(&pdu->u.ret_unlink, send);
513 		break;
514 	default:
515 		/* NOT REACHED */
516 		pr_err("unknown command\n");
517 		break;
518 	}
519 }
520 EXPORT_SYMBOL_GPL(usbip_header_correct_endian);
521 
522 static void usbip_iso_packet_correct_endian(
523 		struct usbip_iso_packet_descriptor *iso, int send)
524 {
525 	/* does not need all members. but copy all simply. */
526 	if (send) {
527 		iso->offset	= cpu_to_be32(iso->offset);
528 		iso->length	= cpu_to_be32(iso->length);
529 		iso->status	= cpu_to_be32(iso->status);
530 		iso->actual_length = cpu_to_be32(iso->actual_length);
531 	} else {
532 		iso->offset	= be32_to_cpu(iso->offset);
533 		iso->length	= be32_to_cpu(iso->length);
534 		iso->status	= be32_to_cpu(iso->status);
535 		iso->actual_length = be32_to_cpu(iso->actual_length);
536 	}
537 }
538 
539 static void usbip_pack_iso(struct usbip_iso_packet_descriptor *iso,
540 			   struct usb_iso_packet_descriptor *uiso, int pack)
541 {
542 	if (pack) {
543 		iso->offset		= uiso->offset;
544 		iso->length		= uiso->length;
545 		iso->status		= uiso->status;
546 		iso->actual_length	= uiso->actual_length;
547 	} else {
548 		uiso->offset		= iso->offset;
549 		uiso->length		= iso->length;
550 		uiso->status		= iso->status;
551 		uiso->actual_length	= iso->actual_length;
552 	}
553 }
554 
555 /* must free buffer */
556 struct usbip_iso_packet_descriptor*
557 usbip_alloc_iso_desc_pdu(struct urb *urb, ssize_t *bufflen)
558 {
559 	struct usbip_iso_packet_descriptor *iso;
560 	int np = urb->number_of_packets;
561 	ssize_t size = np * sizeof(*iso);
562 	int i;
563 
564 	iso = kzalloc(size, GFP_KERNEL);
565 	if (!iso)
566 		return NULL;
567 
568 	for (i = 0; i < np; i++) {
569 		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 1);
570 		usbip_iso_packet_correct_endian(&iso[i], 1);
571 	}
572 
573 	*bufflen = size;
574 
575 	return iso;
576 }
577 EXPORT_SYMBOL_GPL(usbip_alloc_iso_desc_pdu);
578 
579 /* some members of urb must be substituted before. */
580 int usbip_recv_iso(struct usbip_device *ud, struct urb *urb)
581 {
582 	void *buff;
583 	struct usbip_iso_packet_descriptor *iso;
584 	int np = urb->number_of_packets;
585 	int size = np * sizeof(*iso);
586 	int i;
587 	int ret;
588 	int total_length = 0;
589 
590 	if (!usb_pipeisoc(urb->pipe))
591 		return 0;
592 
593 	/* my Bluetooth dongle gets ISO URBs which are np = 0 */
594 	if (np == 0)
595 		return 0;
596 
597 	buff = kzalloc(size, GFP_KERNEL);
598 	if (!buff)
599 		return -ENOMEM;
600 
601 	ret = usbip_recv(ud->tcp_socket, buff, size);
602 	if (ret != size) {
603 		dev_err(&urb->dev->dev, "recv iso_frame_descriptor, %d\n",
604 			ret);
605 		kfree(buff);
606 
607 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
608 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
609 		else
610 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
611 
612 		return -EPIPE;
613 	}
614 
615 	iso = (struct usbip_iso_packet_descriptor *) buff;
616 	for (i = 0; i < np; i++) {
617 		usbip_iso_packet_correct_endian(&iso[i], 0);
618 		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 0);
619 		total_length += urb->iso_frame_desc[i].actual_length;
620 	}
621 
622 	kfree(buff);
623 
624 	if (total_length != urb->actual_length) {
625 		dev_err(&urb->dev->dev,
626 			"total length of iso packets %d not equal to actual length of buffer %d\n",
627 			total_length, urb->actual_length);
628 
629 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
630 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
631 		else
632 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
633 
634 		return -EPIPE;
635 	}
636 
637 	return ret;
638 }
639 EXPORT_SYMBOL_GPL(usbip_recv_iso);
640 
641 /*
642  * This functions restores the padding which was removed for optimizing
643  * the bandwidth during transfer over tcp/ip
644  *
645  * buffer and iso packets need to be stored and be in propeper endian in urb
646  * before calling this function
647  */
648 void usbip_pad_iso(struct usbip_device *ud, struct urb *urb)
649 {
650 	int np = urb->number_of_packets;
651 	int i;
652 	int actualoffset = urb->actual_length;
653 
654 	if (!usb_pipeisoc(urb->pipe))
655 		return;
656 
657 	/* if no packets or length of data is 0, then nothing to unpack */
658 	if (np == 0 || urb->actual_length == 0)
659 		return;
660 
661 	/*
662 	 * if actual_length is transfer_buffer_length then no padding is
663 	 * present.
664 	 */
665 	if (urb->actual_length == urb->transfer_buffer_length)
666 		return;
667 
668 	/*
669 	 * loop over all packets from last to first (to prevent overwriting
670 	 * memory when padding) and move them into the proper place
671 	 */
672 	for (i = np-1; i > 0; i--) {
673 		actualoffset -= urb->iso_frame_desc[i].actual_length;
674 		memmove(urb->transfer_buffer + urb->iso_frame_desc[i].offset,
675 			urb->transfer_buffer + actualoffset,
676 			urb->iso_frame_desc[i].actual_length);
677 	}
678 }
679 EXPORT_SYMBOL_GPL(usbip_pad_iso);
680 
681 /* some members of urb must be substituted before. */
682 int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
683 {
684 	int ret;
685 	int size;
686 
687 	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
688 		/* the direction of urb must be OUT. */
689 		if (usb_pipein(urb->pipe))
690 			return 0;
691 
692 		size = urb->transfer_buffer_length;
693 	} else {
694 		/* the direction of urb must be IN. */
695 		if (usb_pipeout(urb->pipe))
696 			return 0;
697 
698 		size = urb->actual_length;
699 	}
700 
701 	/* no need to recv xbuff */
702 	if (!(size > 0))
703 		return 0;
704 
705 	if (size > urb->transfer_buffer_length) {
706 		/* should not happen, probably malicious packet */
707 		if (ud->side == USBIP_STUB) {
708 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
709 			return 0;
710 		} else {
711 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
712 			return -EPIPE;
713 		}
714 	}
715 
716 	ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
717 	if (ret != size) {
718 		dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
719 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
720 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
721 		} else {
722 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
723 			return -EPIPE;
724 		}
725 	}
726 
727 	return ret;
728 }
729 EXPORT_SYMBOL_GPL(usbip_recv_xbuff);
730 
731 static int __init usbip_core_init(void)
732 {
733 	int ret;
734 
735 	ret = usbip_init_eh();
736 	if (ret)
737 		return ret;
738 
739 	return 0;
740 }
741 
742 static void __exit usbip_core_exit(void)
743 {
744 	usbip_finish_eh();
745 	return;
746 }
747 
748 module_init(usbip_core_init);
749 module_exit(usbip_core_exit);
750 
751 MODULE_AUTHOR(DRIVER_AUTHOR);
752 MODULE_DESCRIPTION(DRIVER_DESC);
753 MODULE_LICENSE("GPL");
754