xref: /openbmc/linux/drivers/usb/usbip/usbip_common.c (revision fb574682)
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, &iov, 1, size);
313 
314 	usbip_dbg_xmit("enter\n");
315 
316 	do {
317 		sock->sk->sk_allocation = GFP_NOIO;
318 
319 		result = sock_recvmsg(sock, &msg, MSG_WAITALL);
320 		if (result <= 0)
321 			goto err;
322 
323 		total += result;
324 	} while (msg_data_left(&msg));
325 
326 	if (usbip_dbg_flag_xmit) {
327 		if (!in_interrupt())
328 			pr_debug("%-10s:", current->comm);
329 		else
330 			pr_debug("interrupt  :");
331 
332 		pr_debug("receiving....\n");
333 		usbip_dump_buffer(buf, size);
334 		pr_debug("received, osize %d ret %d size %zd total %d\n",
335 			 size, result, msg_data_left(&msg), total);
336 	}
337 
338 	return total;
339 
340 err:
341 	return result;
342 }
343 EXPORT_SYMBOL_GPL(usbip_recv);
344 
345 /* there may be more cases to tweak the flags. */
346 static unsigned int tweak_transfer_flags(unsigned int flags)
347 {
348 	flags &= ~URB_NO_TRANSFER_DMA_MAP;
349 	return flags;
350 }
351 
352 static void usbip_pack_cmd_submit(struct usbip_header *pdu, struct urb *urb,
353 				  int pack)
354 {
355 	struct usbip_header_cmd_submit *spdu = &pdu->u.cmd_submit;
356 
357 	/*
358 	 * Some members are not still implemented in usbip. I hope this issue
359 	 * will be discussed when usbip is ported to other operating systems.
360 	 */
361 	if (pack) {
362 		spdu->transfer_flags =
363 			tweak_transfer_flags(urb->transfer_flags);
364 		spdu->transfer_buffer_length	= urb->transfer_buffer_length;
365 		spdu->start_frame		= urb->start_frame;
366 		spdu->number_of_packets		= urb->number_of_packets;
367 		spdu->interval			= urb->interval;
368 	} else  {
369 		urb->transfer_flags         = spdu->transfer_flags;
370 		urb->transfer_buffer_length = spdu->transfer_buffer_length;
371 		urb->start_frame            = spdu->start_frame;
372 		urb->number_of_packets      = spdu->number_of_packets;
373 		urb->interval               = spdu->interval;
374 	}
375 }
376 
377 static void usbip_pack_ret_submit(struct usbip_header *pdu, struct urb *urb,
378 				  int pack)
379 {
380 	struct usbip_header_ret_submit *rpdu = &pdu->u.ret_submit;
381 
382 	if (pack) {
383 		rpdu->status		= urb->status;
384 		rpdu->actual_length	= urb->actual_length;
385 		rpdu->start_frame	= urb->start_frame;
386 		rpdu->number_of_packets = urb->number_of_packets;
387 		rpdu->error_count	= urb->error_count;
388 	} else {
389 		urb->status		= rpdu->status;
390 		urb->actual_length	= rpdu->actual_length;
391 		urb->start_frame	= rpdu->start_frame;
392 		urb->number_of_packets = rpdu->number_of_packets;
393 		urb->error_count	= rpdu->error_count;
394 	}
395 }
396 
397 void usbip_pack_pdu(struct usbip_header *pdu, struct urb *urb, int cmd,
398 		    int pack)
399 {
400 	switch (cmd) {
401 	case USBIP_CMD_SUBMIT:
402 		usbip_pack_cmd_submit(pdu, urb, pack);
403 		break;
404 	case USBIP_RET_SUBMIT:
405 		usbip_pack_ret_submit(pdu, urb, pack);
406 		break;
407 	default:
408 		/* NOT REACHED */
409 		pr_err("unknown command\n");
410 		break;
411 	}
412 }
413 EXPORT_SYMBOL_GPL(usbip_pack_pdu);
414 
415 static void correct_endian_basic(struct usbip_header_basic *base, int send)
416 {
417 	if (send) {
418 		base->command	= cpu_to_be32(base->command);
419 		base->seqnum	= cpu_to_be32(base->seqnum);
420 		base->devid	= cpu_to_be32(base->devid);
421 		base->direction	= cpu_to_be32(base->direction);
422 		base->ep	= cpu_to_be32(base->ep);
423 	} else {
424 		base->command	= be32_to_cpu(base->command);
425 		base->seqnum	= be32_to_cpu(base->seqnum);
426 		base->devid	= be32_to_cpu(base->devid);
427 		base->direction	= be32_to_cpu(base->direction);
428 		base->ep	= be32_to_cpu(base->ep);
429 	}
430 }
431 
432 static void correct_endian_cmd_submit(struct usbip_header_cmd_submit *pdu,
433 				      int send)
434 {
435 	if (send) {
436 		pdu->transfer_flags = cpu_to_be32(pdu->transfer_flags);
437 
438 		cpu_to_be32s(&pdu->transfer_buffer_length);
439 		cpu_to_be32s(&pdu->start_frame);
440 		cpu_to_be32s(&pdu->number_of_packets);
441 		cpu_to_be32s(&pdu->interval);
442 	} else {
443 		pdu->transfer_flags = be32_to_cpu(pdu->transfer_flags);
444 
445 		be32_to_cpus(&pdu->transfer_buffer_length);
446 		be32_to_cpus(&pdu->start_frame);
447 		be32_to_cpus(&pdu->number_of_packets);
448 		be32_to_cpus(&pdu->interval);
449 	}
450 }
451 
452 static void correct_endian_ret_submit(struct usbip_header_ret_submit *pdu,
453 				      int send)
454 {
455 	if (send) {
456 		cpu_to_be32s(&pdu->status);
457 		cpu_to_be32s(&pdu->actual_length);
458 		cpu_to_be32s(&pdu->start_frame);
459 		cpu_to_be32s(&pdu->number_of_packets);
460 		cpu_to_be32s(&pdu->error_count);
461 	} else {
462 		be32_to_cpus(&pdu->status);
463 		be32_to_cpus(&pdu->actual_length);
464 		be32_to_cpus(&pdu->start_frame);
465 		be32_to_cpus(&pdu->number_of_packets);
466 		be32_to_cpus(&pdu->error_count);
467 	}
468 }
469 
470 static void correct_endian_cmd_unlink(struct usbip_header_cmd_unlink *pdu,
471 				      int send)
472 {
473 	if (send)
474 		pdu->seqnum = cpu_to_be32(pdu->seqnum);
475 	else
476 		pdu->seqnum = be32_to_cpu(pdu->seqnum);
477 }
478 
479 static void correct_endian_ret_unlink(struct usbip_header_ret_unlink *pdu,
480 				      int send)
481 {
482 	if (send)
483 		cpu_to_be32s(&pdu->status);
484 	else
485 		be32_to_cpus(&pdu->status);
486 }
487 
488 void usbip_header_correct_endian(struct usbip_header *pdu, int send)
489 {
490 	__u32 cmd = 0;
491 
492 	if (send)
493 		cmd = pdu->base.command;
494 
495 	correct_endian_basic(&pdu->base, send);
496 
497 	if (!send)
498 		cmd = pdu->base.command;
499 
500 	switch (cmd) {
501 	case USBIP_CMD_SUBMIT:
502 		correct_endian_cmd_submit(&pdu->u.cmd_submit, send);
503 		break;
504 	case USBIP_RET_SUBMIT:
505 		correct_endian_ret_submit(&pdu->u.ret_submit, send);
506 		break;
507 	case USBIP_CMD_UNLINK:
508 		correct_endian_cmd_unlink(&pdu->u.cmd_unlink, send);
509 		break;
510 	case USBIP_RET_UNLINK:
511 		correct_endian_ret_unlink(&pdu->u.ret_unlink, send);
512 		break;
513 	default:
514 		/* NOT REACHED */
515 		pr_err("unknown command\n");
516 		break;
517 	}
518 }
519 EXPORT_SYMBOL_GPL(usbip_header_correct_endian);
520 
521 static void usbip_iso_packet_correct_endian(
522 		struct usbip_iso_packet_descriptor *iso, int send)
523 {
524 	/* does not need all members. but copy all simply. */
525 	if (send) {
526 		iso->offset	= cpu_to_be32(iso->offset);
527 		iso->length	= cpu_to_be32(iso->length);
528 		iso->status	= cpu_to_be32(iso->status);
529 		iso->actual_length = cpu_to_be32(iso->actual_length);
530 	} else {
531 		iso->offset	= be32_to_cpu(iso->offset);
532 		iso->length	= be32_to_cpu(iso->length);
533 		iso->status	= be32_to_cpu(iso->status);
534 		iso->actual_length = be32_to_cpu(iso->actual_length);
535 	}
536 }
537 
538 static void usbip_pack_iso(struct usbip_iso_packet_descriptor *iso,
539 			   struct usb_iso_packet_descriptor *uiso, int pack)
540 {
541 	if (pack) {
542 		iso->offset		= uiso->offset;
543 		iso->length		= uiso->length;
544 		iso->status		= uiso->status;
545 		iso->actual_length	= uiso->actual_length;
546 	} else {
547 		uiso->offset		= iso->offset;
548 		uiso->length		= iso->length;
549 		uiso->status		= iso->status;
550 		uiso->actual_length	= iso->actual_length;
551 	}
552 }
553 
554 /* must free buffer */
555 struct usbip_iso_packet_descriptor*
556 usbip_alloc_iso_desc_pdu(struct urb *urb, ssize_t *bufflen)
557 {
558 	struct usbip_iso_packet_descriptor *iso;
559 	int np = urb->number_of_packets;
560 	ssize_t size = np * sizeof(*iso);
561 	int i;
562 
563 	iso = kzalloc(size, GFP_KERNEL);
564 	if (!iso)
565 		return NULL;
566 
567 	for (i = 0; i < np; i++) {
568 		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 1);
569 		usbip_iso_packet_correct_endian(&iso[i], 1);
570 	}
571 
572 	*bufflen = size;
573 
574 	return iso;
575 }
576 EXPORT_SYMBOL_GPL(usbip_alloc_iso_desc_pdu);
577 
578 /* some members of urb must be substituted before. */
579 int usbip_recv_iso(struct usbip_device *ud, struct urb *urb)
580 {
581 	void *buff;
582 	struct usbip_iso_packet_descriptor *iso;
583 	int np = urb->number_of_packets;
584 	int size = np * sizeof(*iso);
585 	int i;
586 	int ret;
587 	int total_length = 0;
588 
589 	if (!usb_pipeisoc(urb->pipe))
590 		return 0;
591 
592 	/* my Bluetooth dongle gets ISO URBs which are np = 0 */
593 	if (np == 0)
594 		return 0;
595 
596 	buff = kzalloc(size, GFP_KERNEL);
597 	if (!buff)
598 		return -ENOMEM;
599 
600 	ret = usbip_recv(ud->tcp_socket, buff, size);
601 	if (ret != size) {
602 		dev_err(&urb->dev->dev, "recv iso_frame_descriptor, %d\n",
603 			ret);
604 		kfree(buff);
605 
606 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
607 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
608 		else
609 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
610 
611 		return -EPIPE;
612 	}
613 
614 	iso = (struct usbip_iso_packet_descriptor *) buff;
615 	for (i = 0; i < np; i++) {
616 		usbip_iso_packet_correct_endian(&iso[i], 0);
617 		usbip_pack_iso(&iso[i], &urb->iso_frame_desc[i], 0);
618 		total_length += urb->iso_frame_desc[i].actual_length;
619 	}
620 
621 	kfree(buff);
622 
623 	if (total_length != urb->actual_length) {
624 		dev_err(&urb->dev->dev,
625 			"total length of iso packets %d not equal to actual length of buffer %d\n",
626 			total_length, urb->actual_length);
627 
628 		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
629 			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
630 		else
631 			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
632 
633 		return -EPIPE;
634 	}
635 
636 	return ret;
637 }
638 EXPORT_SYMBOL_GPL(usbip_recv_iso);
639 
640 /*
641  * This functions restores the padding which was removed for optimizing
642  * the bandwidth during transfer over tcp/ip
643  *
644  * buffer and iso packets need to be stored and be in propeper endian in urb
645  * before calling this function
646  */
647 void usbip_pad_iso(struct usbip_device *ud, struct urb *urb)
648 {
649 	int np = urb->number_of_packets;
650 	int i;
651 	int actualoffset = urb->actual_length;
652 
653 	if (!usb_pipeisoc(urb->pipe))
654 		return;
655 
656 	/* if no packets or length of data is 0, then nothing to unpack */
657 	if (np == 0 || urb->actual_length == 0)
658 		return;
659 
660 	/*
661 	 * if actual_length is transfer_buffer_length then no padding is
662 	 * present.
663 	 */
664 	if (urb->actual_length == urb->transfer_buffer_length)
665 		return;
666 
667 	/*
668 	 * loop over all packets from last to first (to prevent overwriting
669 	 * memory when padding) and move them into the proper place
670 	 */
671 	for (i = np-1; i > 0; i--) {
672 		actualoffset -= urb->iso_frame_desc[i].actual_length;
673 		memmove(urb->transfer_buffer + urb->iso_frame_desc[i].offset,
674 			urb->transfer_buffer + actualoffset,
675 			urb->iso_frame_desc[i].actual_length);
676 	}
677 }
678 EXPORT_SYMBOL_GPL(usbip_pad_iso);
679 
680 /* some members of urb must be substituted before. */
681 int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
682 {
683 	struct scatterlist *sg;
684 	int ret = 0;
685 	int recv;
686 	int size;
687 	int copy;
688 	int i;
689 
690 	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
691 		/* the direction of urb must be OUT. */
692 		if (usb_pipein(urb->pipe))
693 			return 0;
694 
695 		size = urb->transfer_buffer_length;
696 	} else {
697 		/* the direction of urb must be IN. */
698 		if (usb_pipeout(urb->pipe))
699 			return 0;
700 
701 		size = urb->actual_length;
702 	}
703 
704 	/* no need to recv xbuff */
705 	if (!(size > 0))
706 		return 0;
707 
708 	if (size > urb->transfer_buffer_length)
709 		/* should not happen, probably malicious packet */
710 		goto error;
711 
712 	if (urb->num_sgs) {
713 		copy = size;
714 		for_each_sg(urb->sg, sg, urb->num_sgs, i) {
715 			int recv_size;
716 
717 			if (copy < sg->length)
718 				recv_size = copy;
719 			else
720 				recv_size = sg->length;
721 
722 			recv = usbip_recv(ud->tcp_socket, sg_virt(sg),
723 						recv_size);
724 
725 			if (recv != recv_size)
726 				goto error;
727 
728 			copy -= recv;
729 			ret += recv;
730 
731 			if (!copy)
732 				break;
733 		}
734 
735 		if (ret != size)
736 			goto error;
737 	} else {
738 		ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
739 		if (ret != size)
740 			goto error;
741 	}
742 
743 	return ret;
744 
745 error:
746 	dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
747 	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
748 		usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
749 	else
750 		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
751 
752 	return -EPIPE;
753 }
754 EXPORT_SYMBOL_GPL(usbip_recv_xbuff);
755 
756 static int __init usbip_core_init(void)
757 {
758 	int ret;
759 
760 	ret = usbip_init_eh();
761 	if (ret)
762 		return ret;
763 
764 	return 0;
765 }
766 
767 static void __exit usbip_core_exit(void)
768 {
769 	usbip_finish_eh();
770 	return;
771 }
772 
773 module_init(usbip_core_init);
774 module_exit(usbip_core_exit);
775 
776 MODULE_AUTHOR(DRIVER_AUTHOR);
777 MODULE_DESCRIPTION(DRIVER_DESC);
778 MODULE_LICENSE("GPL");
779