1 /*
2  * f_rndis.c -- RNDIS link function driver
3  *
4  * Copyright (C) 2003-2005,2008 David Brownell
5  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
6  * Copyright (C) 2008 Nokia Corporation
7  * Copyright (C) 2009 Samsung Electronics
8  *                    Author: Michal Nazarewicz (mina86@mina86.com)
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  */
15 
16 /* #define VERBOSE_DEBUG */
17 
18 #include <linux/slab.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/device.h>
22 #include <linux/etherdevice.h>
23 
24 #include <linux/atomic.h>
25 
26 #include "u_ether.h"
27 #include "u_ether_configfs.h"
28 #include "u_rndis.h"
29 #include "rndis.h"
30 #include "configfs.h"
31 
32 /*
33  * This function is an RNDIS Ethernet port -- a Microsoft protocol that's
34  * been promoted instead of the standard CDC Ethernet.  The published RNDIS
35  * spec is ambiguous, incomplete, and needlessly complex.  Variants such as
36  * ActiveSync have even worse status in terms of specification.
37  *
38  * In short:  it's a protocol controlled by (and for) Microsoft, not for an
39  * Open ecosystem or markets.  Linux supports it *only* because Microsoft
40  * doesn't support the CDC Ethernet standard.
41  *
42  * The RNDIS data transfer model is complex, with multiple Ethernet packets
43  * per USB message, and out of band data.  The control model is built around
44  * what's essentially an "RNDIS RPC" protocol.  It's all wrapped in a CDC ACM
45  * (modem, not Ethernet) veneer, with those ACM descriptors being entirely
46  * useless (they're ignored).  RNDIS expects to be the only function in its
47  * configuration, so it's no real help if you need composite devices; and
48  * it expects to be the first configuration too.
49  *
50  * There is a single technical advantage of RNDIS over CDC Ethernet, if you
51  * discount the fluff that its RPC can be made to deliver: it doesn't need
52  * a NOP altsetting for the data interface.  That lets it work on some of the
53  * "so smart it's stupid" hardware which takes over configuration changes
54  * from the software, and adds restrictions like "no altsettings".
55  *
56  * Unfortunately MSFT's RNDIS drivers are buggy.  They hang or oops, and
57  * have all sorts of contrary-to-specification oddities that can prevent
58  * them from working sanely.  Since bugfixes (or accurate specs, letting
59  * Linux work around those bugs) are unlikely to ever come from MSFT, you
60  * may want to avoid using RNDIS on purely operational grounds.
61  *
62  * Omissions from the RNDIS 1.0 specification include:
63  *
64  *   - Power management ... references data that's scattered around lots
65  *     of other documentation, which is incorrect/incomplete there too.
66  *
67  *   - There are various undocumented protocol requirements, like the need
68  *     to send garbage in some control-OUT messages.
69  *
70  *   - MS-Windows drivers sometimes emit undocumented requests.
71  */
72 
73 struct f_rndis {
74 	struct gether			port;
75 	u8				ctrl_id, data_id;
76 	u8				ethaddr[ETH_ALEN];
77 	u32				vendorID;
78 	const char			*manufacturer;
79 	struct rndis_params		*params;
80 
81 	struct usb_ep			*notify;
82 	struct usb_request		*notify_req;
83 	atomic_t			notify_count;
84 };
85 
86 static inline struct f_rndis *func_to_rndis(struct usb_function *f)
87 {
88 	return container_of(f, struct f_rndis, port.func);
89 }
90 
91 /* peak (theoretical) bulk transfer rate in bits-per-second */
92 static unsigned int bitrate(struct usb_gadget *g)
93 {
94 	if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
95 		return 13 * 1024 * 8 * 1000 * 8;
96 	else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
97 		return 13 * 512 * 8 * 1000 * 8;
98 	else
99 		return 19 * 64 * 1 * 1000 * 8;
100 }
101 
102 /*-------------------------------------------------------------------------*/
103 
104 /*
105  */
106 
107 #define RNDIS_STATUS_INTERVAL_MS	32
108 #define STATUS_BYTECOUNT		8	/* 8 bytes data */
109 
110 
111 /* interface descriptor: */
112 
113 static struct usb_interface_descriptor rndis_control_intf = {
114 	.bLength =		sizeof rndis_control_intf,
115 	.bDescriptorType =	USB_DT_INTERFACE,
116 
117 	/* .bInterfaceNumber = DYNAMIC */
118 	/* status endpoint is optional; this could be patched later */
119 	.bNumEndpoints =	1,
120 	.bInterfaceClass =	USB_CLASS_COMM,
121 	.bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
122 	.bInterfaceProtocol =   USB_CDC_ACM_PROTO_VENDOR,
123 	/* .iInterface = DYNAMIC */
124 };
125 
126 static struct usb_cdc_header_desc header_desc = {
127 	.bLength =		sizeof header_desc,
128 	.bDescriptorType =	USB_DT_CS_INTERFACE,
129 	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
130 
131 	.bcdCDC =		cpu_to_le16(0x0110),
132 };
133 
134 static struct usb_cdc_call_mgmt_descriptor call_mgmt_descriptor = {
135 	.bLength =		sizeof call_mgmt_descriptor,
136 	.bDescriptorType =	USB_DT_CS_INTERFACE,
137 	.bDescriptorSubType =	USB_CDC_CALL_MANAGEMENT_TYPE,
138 
139 	.bmCapabilities =	0x00,
140 	.bDataInterface =	0x01,
141 };
142 
143 static struct usb_cdc_acm_descriptor rndis_acm_descriptor = {
144 	.bLength =		sizeof rndis_acm_descriptor,
145 	.bDescriptorType =	USB_DT_CS_INTERFACE,
146 	.bDescriptorSubType =	USB_CDC_ACM_TYPE,
147 
148 	.bmCapabilities =	0x00,
149 };
150 
151 static struct usb_cdc_union_desc rndis_union_desc = {
152 	.bLength =		sizeof(rndis_union_desc),
153 	.bDescriptorType =	USB_DT_CS_INTERFACE,
154 	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
155 	/* .bMasterInterface0 =	DYNAMIC */
156 	/* .bSlaveInterface0 =	DYNAMIC */
157 };
158 
159 /* the data interface has two bulk endpoints */
160 
161 static struct usb_interface_descriptor rndis_data_intf = {
162 	.bLength =		sizeof rndis_data_intf,
163 	.bDescriptorType =	USB_DT_INTERFACE,
164 
165 	/* .bInterfaceNumber = DYNAMIC */
166 	.bNumEndpoints =	2,
167 	.bInterfaceClass =	USB_CLASS_CDC_DATA,
168 	.bInterfaceSubClass =	0,
169 	.bInterfaceProtocol =	0,
170 	/* .iInterface = DYNAMIC */
171 };
172 
173 
174 static struct usb_interface_assoc_descriptor
175 rndis_iad_descriptor = {
176 	.bLength =		sizeof rndis_iad_descriptor,
177 	.bDescriptorType =	USB_DT_INTERFACE_ASSOCIATION,
178 
179 	.bFirstInterface =	0, /* XXX, hardcoded */
180 	.bInterfaceCount = 	2,	// control + data
181 	.bFunctionClass =	USB_CLASS_COMM,
182 	.bFunctionSubClass =	USB_CDC_SUBCLASS_ETHERNET,
183 	.bFunctionProtocol =	USB_CDC_PROTO_NONE,
184 	/* .iFunction = DYNAMIC */
185 };
186 
187 /* full speed support: */
188 
189 static struct usb_endpoint_descriptor fs_notify_desc = {
190 	.bLength =		USB_DT_ENDPOINT_SIZE,
191 	.bDescriptorType =	USB_DT_ENDPOINT,
192 
193 	.bEndpointAddress =	USB_DIR_IN,
194 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
195 	.wMaxPacketSize =	cpu_to_le16(STATUS_BYTECOUNT),
196 	.bInterval =		RNDIS_STATUS_INTERVAL_MS,
197 };
198 
199 static struct usb_endpoint_descriptor fs_in_desc = {
200 	.bLength =		USB_DT_ENDPOINT_SIZE,
201 	.bDescriptorType =	USB_DT_ENDPOINT,
202 
203 	.bEndpointAddress =	USB_DIR_IN,
204 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
205 };
206 
207 static struct usb_endpoint_descriptor fs_out_desc = {
208 	.bLength =		USB_DT_ENDPOINT_SIZE,
209 	.bDescriptorType =	USB_DT_ENDPOINT,
210 
211 	.bEndpointAddress =	USB_DIR_OUT,
212 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
213 };
214 
215 static struct usb_descriptor_header *eth_fs_function[] = {
216 	(struct usb_descriptor_header *) &rndis_iad_descriptor,
217 
218 	/* control interface matches ACM, not Ethernet */
219 	(struct usb_descriptor_header *) &rndis_control_intf,
220 	(struct usb_descriptor_header *) &header_desc,
221 	(struct usb_descriptor_header *) &call_mgmt_descriptor,
222 	(struct usb_descriptor_header *) &rndis_acm_descriptor,
223 	(struct usb_descriptor_header *) &rndis_union_desc,
224 	(struct usb_descriptor_header *) &fs_notify_desc,
225 
226 	/* data interface has no altsetting */
227 	(struct usb_descriptor_header *) &rndis_data_intf,
228 	(struct usb_descriptor_header *) &fs_in_desc,
229 	(struct usb_descriptor_header *) &fs_out_desc,
230 	NULL,
231 };
232 
233 /* high speed support: */
234 
235 static struct usb_endpoint_descriptor hs_notify_desc = {
236 	.bLength =		USB_DT_ENDPOINT_SIZE,
237 	.bDescriptorType =	USB_DT_ENDPOINT,
238 
239 	.bEndpointAddress =	USB_DIR_IN,
240 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
241 	.wMaxPacketSize =	cpu_to_le16(STATUS_BYTECOUNT),
242 	.bInterval =		USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
243 };
244 
245 static struct usb_endpoint_descriptor hs_in_desc = {
246 	.bLength =		USB_DT_ENDPOINT_SIZE,
247 	.bDescriptorType =	USB_DT_ENDPOINT,
248 
249 	.bEndpointAddress =	USB_DIR_IN,
250 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
251 	.wMaxPacketSize =	cpu_to_le16(512),
252 };
253 
254 static struct usb_endpoint_descriptor hs_out_desc = {
255 	.bLength =		USB_DT_ENDPOINT_SIZE,
256 	.bDescriptorType =	USB_DT_ENDPOINT,
257 
258 	.bEndpointAddress =	USB_DIR_OUT,
259 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
260 	.wMaxPacketSize =	cpu_to_le16(512),
261 };
262 
263 static struct usb_descriptor_header *eth_hs_function[] = {
264 	(struct usb_descriptor_header *) &rndis_iad_descriptor,
265 
266 	/* control interface matches ACM, not Ethernet */
267 	(struct usb_descriptor_header *) &rndis_control_intf,
268 	(struct usb_descriptor_header *) &header_desc,
269 	(struct usb_descriptor_header *) &call_mgmt_descriptor,
270 	(struct usb_descriptor_header *) &rndis_acm_descriptor,
271 	(struct usb_descriptor_header *) &rndis_union_desc,
272 	(struct usb_descriptor_header *) &hs_notify_desc,
273 
274 	/* data interface has no altsetting */
275 	(struct usb_descriptor_header *) &rndis_data_intf,
276 	(struct usb_descriptor_header *) &hs_in_desc,
277 	(struct usb_descriptor_header *) &hs_out_desc,
278 	NULL,
279 };
280 
281 /* super speed support: */
282 
283 static struct usb_endpoint_descriptor ss_notify_desc = {
284 	.bLength =		USB_DT_ENDPOINT_SIZE,
285 	.bDescriptorType =	USB_DT_ENDPOINT,
286 
287 	.bEndpointAddress =	USB_DIR_IN,
288 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
289 	.wMaxPacketSize =	cpu_to_le16(STATUS_BYTECOUNT),
290 	.bInterval =		USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
291 };
292 
293 static struct usb_ss_ep_comp_descriptor ss_intr_comp_desc = {
294 	.bLength =		sizeof ss_intr_comp_desc,
295 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
296 
297 	/* the following 3 values can be tweaked if necessary */
298 	/* .bMaxBurst =		0, */
299 	/* .bmAttributes =	0, */
300 	.wBytesPerInterval =	cpu_to_le16(STATUS_BYTECOUNT),
301 };
302 
303 static struct usb_endpoint_descriptor ss_in_desc = {
304 	.bLength =		USB_DT_ENDPOINT_SIZE,
305 	.bDescriptorType =	USB_DT_ENDPOINT,
306 
307 	.bEndpointAddress =	USB_DIR_IN,
308 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
309 	.wMaxPacketSize =	cpu_to_le16(1024),
310 };
311 
312 static struct usb_endpoint_descriptor ss_out_desc = {
313 	.bLength =		USB_DT_ENDPOINT_SIZE,
314 	.bDescriptorType =	USB_DT_ENDPOINT,
315 
316 	.bEndpointAddress =	USB_DIR_OUT,
317 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
318 	.wMaxPacketSize =	cpu_to_le16(1024),
319 };
320 
321 static struct usb_ss_ep_comp_descriptor ss_bulk_comp_desc = {
322 	.bLength =		sizeof ss_bulk_comp_desc,
323 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
324 
325 	/* the following 2 values can be tweaked if necessary */
326 	/* .bMaxBurst =		0, */
327 	/* .bmAttributes =	0, */
328 };
329 
330 static struct usb_descriptor_header *eth_ss_function[] = {
331 	(struct usb_descriptor_header *) &rndis_iad_descriptor,
332 
333 	/* control interface matches ACM, not Ethernet */
334 	(struct usb_descriptor_header *) &rndis_control_intf,
335 	(struct usb_descriptor_header *) &header_desc,
336 	(struct usb_descriptor_header *) &call_mgmt_descriptor,
337 	(struct usb_descriptor_header *) &rndis_acm_descriptor,
338 	(struct usb_descriptor_header *) &rndis_union_desc,
339 	(struct usb_descriptor_header *) &ss_notify_desc,
340 	(struct usb_descriptor_header *) &ss_intr_comp_desc,
341 
342 	/* data interface has no altsetting */
343 	(struct usb_descriptor_header *) &rndis_data_intf,
344 	(struct usb_descriptor_header *) &ss_in_desc,
345 	(struct usb_descriptor_header *) &ss_bulk_comp_desc,
346 	(struct usb_descriptor_header *) &ss_out_desc,
347 	(struct usb_descriptor_header *) &ss_bulk_comp_desc,
348 	NULL,
349 };
350 
351 /* string descriptors: */
352 
353 static struct usb_string rndis_string_defs[] = {
354 	[0].s = "RNDIS Communications Control",
355 	[1].s = "RNDIS Ethernet Data",
356 	[2].s = "RNDIS",
357 	{  } /* end of list */
358 };
359 
360 static struct usb_gadget_strings rndis_string_table = {
361 	.language =		0x0409,	/* en-us */
362 	.strings =		rndis_string_defs,
363 };
364 
365 static struct usb_gadget_strings *rndis_strings[] = {
366 	&rndis_string_table,
367 	NULL,
368 };
369 
370 /*-------------------------------------------------------------------------*/
371 
372 static struct sk_buff *rndis_add_header(struct gether *port,
373 					struct sk_buff *skb)
374 {
375 	struct sk_buff *skb2;
376 
377 	skb2 = skb_realloc_headroom(skb, sizeof(struct rndis_packet_msg_type));
378 	rndis_add_hdr(skb2);
379 
380 	dev_kfree_skb(skb);
381 	return skb2;
382 }
383 
384 static void rndis_response_available(void *_rndis)
385 {
386 	struct f_rndis			*rndis = _rndis;
387 	struct usb_request		*req = rndis->notify_req;
388 	struct usb_composite_dev	*cdev = rndis->port.func.config->cdev;
389 	__le32				*data = req->buf;
390 	int				status;
391 
392 	if (atomic_inc_return(&rndis->notify_count) != 1)
393 		return;
394 
395 	/* Send RNDIS RESPONSE_AVAILABLE notification; a
396 	 * USB_CDC_NOTIFY_RESPONSE_AVAILABLE "should" work too
397 	 *
398 	 * This is the only notification defined by RNDIS.
399 	 */
400 	data[0] = cpu_to_le32(1);
401 	data[1] = cpu_to_le32(0);
402 
403 	status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
404 	if (status) {
405 		atomic_dec(&rndis->notify_count);
406 		DBG(cdev, "notify/0 --> %d\n", status);
407 	}
408 }
409 
410 static void rndis_response_complete(struct usb_ep *ep, struct usb_request *req)
411 {
412 	struct f_rndis			*rndis = req->context;
413 	struct usb_composite_dev	*cdev = rndis->port.func.config->cdev;
414 	int				status = req->status;
415 
416 	/* after TX:
417 	 *  - USB_CDC_GET_ENCAPSULATED_RESPONSE (ep0/control)
418 	 *  - RNDIS_RESPONSE_AVAILABLE (status/irq)
419 	 */
420 	switch (status) {
421 	case -ECONNRESET:
422 	case -ESHUTDOWN:
423 		/* connection gone */
424 		atomic_set(&rndis->notify_count, 0);
425 		break;
426 	default:
427 		DBG(cdev, "RNDIS %s response error %d, %d/%d\n",
428 			ep->name, status,
429 			req->actual, req->length);
430 		/* FALLTHROUGH */
431 	case 0:
432 		if (ep != rndis->notify)
433 			break;
434 
435 		/* handle multiple pending RNDIS_RESPONSE_AVAILABLE
436 		 * notifications by resending until we're done
437 		 */
438 		if (atomic_dec_and_test(&rndis->notify_count))
439 			break;
440 		status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
441 		if (status) {
442 			atomic_dec(&rndis->notify_count);
443 			DBG(cdev, "notify/1 --> %d\n", status);
444 		}
445 		break;
446 	}
447 }
448 
449 static void rndis_command_complete(struct usb_ep *ep, struct usb_request *req)
450 {
451 	struct f_rndis			*rndis = req->context;
452 	int				status;
453 
454 	/* received RNDIS command from USB_CDC_SEND_ENCAPSULATED_COMMAND */
455 //	spin_lock(&dev->lock);
456 	status = rndis_msg_parser(rndis->params, (u8 *) req->buf);
457 	if (status < 0)
458 		pr_err("RNDIS command error %d, %d/%d\n",
459 			status, req->actual, req->length);
460 //	spin_unlock(&dev->lock);
461 }
462 
463 static int
464 rndis_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
465 {
466 	struct f_rndis		*rndis = func_to_rndis(f);
467 	struct usb_composite_dev *cdev = f->config->cdev;
468 	struct usb_request	*req = cdev->req;
469 	int			value = -EOPNOTSUPP;
470 	u16			w_index = le16_to_cpu(ctrl->wIndex);
471 	u16			w_value = le16_to_cpu(ctrl->wValue);
472 	u16			w_length = le16_to_cpu(ctrl->wLength);
473 
474 	/* composite driver infrastructure handles everything except
475 	 * CDC class messages; interface activation uses set_alt().
476 	 */
477 	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
478 
479 	/* RNDIS uses the CDC command encapsulation mechanism to implement
480 	 * an RPC scheme, with much getting/setting of attributes by OID.
481 	 */
482 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
483 			| USB_CDC_SEND_ENCAPSULATED_COMMAND:
484 		if (w_value || w_index != rndis->ctrl_id)
485 			goto invalid;
486 		/* read the request; process it later */
487 		value = w_length;
488 		req->complete = rndis_command_complete;
489 		req->context = rndis;
490 		/* later, rndis_response_available() sends a notification */
491 		break;
492 
493 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
494 			| USB_CDC_GET_ENCAPSULATED_RESPONSE:
495 		if (w_value || w_index != rndis->ctrl_id)
496 			goto invalid;
497 		else {
498 			u8 *buf;
499 			u32 n;
500 
501 			/* return the result */
502 			buf = rndis_get_next_response(rndis->params, &n);
503 			if (buf) {
504 				memcpy(req->buf, buf, n);
505 				req->complete = rndis_response_complete;
506 				req->context = rndis;
507 				rndis_free_response(rndis->params, buf);
508 				value = n;
509 			}
510 			/* else stalls ... spec says to avoid that */
511 		}
512 		break;
513 
514 	default:
515 invalid:
516 		VDBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
517 			ctrl->bRequestType, ctrl->bRequest,
518 			w_value, w_index, w_length);
519 	}
520 
521 	/* respond with data transfer or status phase? */
522 	if (value >= 0) {
523 		DBG(cdev, "rndis req%02x.%02x v%04x i%04x l%d\n",
524 			ctrl->bRequestType, ctrl->bRequest,
525 			w_value, w_index, w_length);
526 		req->zero = (value < w_length);
527 		req->length = value;
528 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
529 		if (value < 0)
530 			ERROR(cdev, "rndis response on err %d\n", value);
531 	}
532 
533 	/* device either stalls (value < 0) or reports success */
534 	return value;
535 }
536 
537 
538 static int rndis_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
539 {
540 	struct f_rndis		*rndis = func_to_rndis(f);
541 	struct usb_composite_dev *cdev = f->config->cdev;
542 
543 	/* we know alt == 0 */
544 
545 	if (intf == rndis->ctrl_id) {
546 		VDBG(cdev, "reset rndis control %d\n", intf);
547 		usb_ep_disable(rndis->notify);
548 
549 		if (!rndis->notify->desc) {
550 			VDBG(cdev, "init rndis ctrl %d\n", intf);
551 			if (config_ep_by_speed(cdev->gadget, f, rndis->notify))
552 				goto fail;
553 		}
554 		usb_ep_enable(rndis->notify);
555 
556 	} else if (intf == rndis->data_id) {
557 		struct net_device	*net;
558 
559 		if (rndis->port.in_ep->enabled) {
560 			DBG(cdev, "reset rndis\n");
561 			gether_disconnect(&rndis->port);
562 		}
563 
564 		if (!rndis->port.in_ep->desc || !rndis->port.out_ep->desc) {
565 			DBG(cdev, "init rndis\n");
566 			if (config_ep_by_speed(cdev->gadget, f,
567 					       rndis->port.in_ep) ||
568 			    config_ep_by_speed(cdev->gadget, f,
569 					       rndis->port.out_ep)) {
570 				rndis->port.in_ep->desc = NULL;
571 				rndis->port.out_ep->desc = NULL;
572 				goto fail;
573 			}
574 		}
575 
576 		/* Avoid ZLPs; they can be troublesome. */
577 		rndis->port.is_zlp_ok = false;
578 
579 		/* RNDIS should be in the "RNDIS uninitialized" state,
580 		 * either never activated or after rndis_uninit().
581 		 *
582 		 * We don't want data to flow here until a nonzero packet
583 		 * filter is set, at which point it enters "RNDIS data
584 		 * initialized" state ... but we do want the endpoints
585 		 * to be activated.  It's a strange little state.
586 		 *
587 		 * REVISIT the RNDIS gadget code has done this wrong for a
588 		 * very long time.  We need another call to the link layer
589 		 * code -- gether_updown(...bool) maybe -- to do it right.
590 		 */
591 		rndis->port.cdc_filter = 0;
592 
593 		DBG(cdev, "RNDIS RX/TX early activation ... \n");
594 		net = gether_connect(&rndis->port);
595 		if (IS_ERR(net))
596 			return PTR_ERR(net);
597 
598 		rndis_set_param_dev(rndis->params, net,
599 				&rndis->port.cdc_filter);
600 	} else
601 		goto fail;
602 
603 	return 0;
604 fail:
605 	return -EINVAL;
606 }
607 
608 static void rndis_disable(struct usb_function *f)
609 {
610 	struct f_rndis		*rndis = func_to_rndis(f);
611 	struct usb_composite_dev *cdev = f->config->cdev;
612 
613 	if (!rndis->notify->enabled)
614 		return;
615 
616 	DBG(cdev, "rndis deactivated\n");
617 
618 	rndis_uninit(rndis->params);
619 	gether_disconnect(&rndis->port);
620 
621 	usb_ep_disable(rndis->notify);
622 }
623 
624 /*-------------------------------------------------------------------------*/
625 
626 /*
627  * This isn't quite the same mechanism as CDC Ethernet, since the
628  * notification scheme passes less data, but the same set of link
629  * states must be tested.  A key difference is that altsettings are
630  * not used to tell whether the link should send packets or not.
631  */
632 
633 static void rndis_open(struct gether *geth)
634 {
635 	struct f_rndis		*rndis = func_to_rndis(&geth->func);
636 	struct usb_composite_dev *cdev = geth->func.config->cdev;
637 
638 	DBG(cdev, "%s\n", __func__);
639 
640 	rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3,
641 				bitrate(cdev->gadget) / 100);
642 	rndis_signal_connect(rndis->params);
643 }
644 
645 static void rndis_close(struct gether *geth)
646 {
647 	struct f_rndis		*rndis = func_to_rndis(&geth->func);
648 
649 	DBG(geth->func.config->cdev, "%s\n", __func__);
650 
651 	rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3, 0);
652 	rndis_signal_disconnect(rndis->params);
653 }
654 
655 /*-------------------------------------------------------------------------*/
656 
657 /* Some controllers can't support RNDIS ... */
658 static inline bool can_support_rndis(struct usb_configuration *c)
659 {
660 	/* everything else is *presumably* fine */
661 	return true;
662 }
663 
664 /* ethernet function driver setup/binding */
665 
666 static int
667 rndis_bind(struct usb_configuration *c, struct usb_function *f)
668 {
669 	struct usb_composite_dev *cdev = c->cdev;
670 	struct f_rndis		*rndis = func_to_rndis(f);
671 	struct usb_string	*us;
672 	int			status;
673 	struct usb_ep		*ep;
674 
675 	struct f_rndis_opts *rndis_opts;
676 
677 	if (!can_support_rndis(c))
678 		return -EINVAL;
679 
680 	rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
681 
682 	if (cdev->use_os_string) {
683 		f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
684 					   GFP_KERNEL);
685 		if (!f->os_desc_table)
686 			return -ENOMEM;
687 		f->os_desc_n = 1;
688 		f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
689 	}
690 
691 	/*
692 	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
693 	 * configurations are bound in sequence with list_for_each_entry,
694 	 * in each configuration its functions are bound in sequence
695 	 * with list_for_each_entry, so we assume no race condition
696 	 * with regard to rndis_opts->bound access
697 	 */
698 	if (!rndis_opts->bound) {
699 		gether_set_gadget(rndis_opts->net, cdev->gadget);
700 		status = gether_register_netdev(rndis_opts->net);
701 		if (status)
702 			goto fail;
703 		rndis_opts->bound = true;
704 	}
705 
706 	us = usb_gstrings_attach(cdev, rndis_strings,
707 				 ARRAY_SIZE(rndis_string_defs));
708 	if (IS_ERR(us)) {
709 		status = PTR_ERR(us);
710 		goto fail;
711 	}
712 	rndis_control_intf.iInterface = us[0].id;
713 	rndis_data_intf.iInterface = us[1].id;
714 	rndis_iad_descriptor.iFunction = us[2].id;
715 
716 	/* allocate instance-specific interface IDs */
717 	status = usb_interface_id(c, f);
718 	if (status < 0)
719 		goto fail;
720 	rndis->ctrl_id = status;
721 	rndis_iad_descriptor.bFirstInterface = status;
722 
723 	rndis_control_intf.bInterfaceNumber = status;
724 	rndis_union_desc.bMasterInterface0 = status;
725 
726 	if (cdev->use_os_string)
727 		f->os_desc_table[0].if_id =
728 			rndis_iad_descriptor.bFirstInterface;
729 
730 	status = usb_interface_id(c, f);
731 	if (status < 0)
732 		goto fail;
733 	rndis->data_id = status;
734 
735 	rndis_data_intf.bInterfaceNumber = status;
736 	rndis_union_desc.bSlaveInterface0 = status;
737 
738 	status = -ENODEV;
739 
740 	/* allocate instance-specific endpoints */
741 	ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc);
742 	if (!ep)
743 		goto fail;
744 	rndis->port.in_ep = ep;
745 
746 	ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc);
747 	if (!ep)
748 		goto fail;
749 	rndis->port.out_ep = ep;
750 
751 	/* NOTE:  a status/notification endpoint is, strictly speaking,
752 	 * optional.  We don't treat it that way though!  It's simpler,
753 	 * and some newer profiles don't treat it as optional.
754 	 */
755 	ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc);
756 	if (!ep)
757 		goto fail;
758 	rndis->notify = ep;
759 
760 	status = -ENOMEM;
761 
762 	/* allocate notification request and buffer */
763 	rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
764 	if (!rndis->notify_req)
765 		goto fail;
766 	rndis->notify_req->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
767 	if (!rndis->notify_req->buf)
768 		goto fail;
769 	rndis->notify_req->length = STATUS_BYTECOUNT;
770 	rndis->notify_req->context = rndis;
771 	rndis->notify_req->complete = rndis_response_complete;
772 
773 	/* support all relevant hardware speeds... we expect that when
774 	 * hardware is dual speed, all bulk-capable endpoints work at
775 	 * both speeds
776 	 */
777 	hs_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
778 	hs_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
779 	hs_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
780 
781 	ss_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
782 	ss_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
783 	ss_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
784 
785 	status = usb_assign_descriptors(f, eth_fs_function, eth_hs_function,
786 			eth_ss_function, NULL);
787 	if (status)
788 		goto fail;
789 
790 	rndis->port.open = rndis_open;
791 	rndis->port.close = rndis_close;
792 
793 	rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3, 0);
794 	rndis_set_host_mac(rndis->params, rndis->ethaddr);
795 
796 	if (rndis->manufacturer && rndis->vendorID &&
797 			rndis_set_param_vendor(rndis->params, rndis->vendorID,
798 					       rndis->manufacturer)) {
799 		status = -EINVAL;
800 		goto fail_free_descs;
801 	}
802 
803 	/* NOTE:  all that is done without knowing or caring about
804 	 * the network link ... which is unavailable to this code
805 	 * until we're activated via set_alt().
806 	 */
807 
808 	DBG(cdev, "RNDIS: %s speed IN/%s OUT/%s NOTIFY/%s\n",
809 			gadget_is_superspeed(c->cdev->gadget) ? "super" :
810 			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
811 			rndis->port.in_ep->name, rndis->port.out_ep->name,
812 			rndis->notify->name);
813 	return 0;
814 
815 fail_free_descs:
816 	usb_free_all_descriptors(f);
817 fail:
818 	kfree(f->os_desc_table);
819 	f->os_desc_n = 0;
820 
821 	if (rndis->notify_req) {
822 		kfree(rndis->notify_req->buf);
823 		usb_ep_free_request(rndis->notify, rndis->notify_req);
824 	}
825 
826 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
827 
828 	return status;
829 }
830 
831 void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)
832 {
833 	struct f_rndis_opts *opts;
834 
835 	opts = container_of(f, struct f_rndis_opts, func_inst);
836 	if (opts->bound)
837 		gether_cleanup(netdev_priv(opts->net));
838 	else
839 		free_netdev(opts->net);
840 	opts->borrowed_net = opts->bound = true;
841 	opts->net = net;
842 }
843 EXPORT_SYMBOL_GPL(rndis_borrow_net);
844 
845 static inline struct f_rndis_opts *to_f_rndis_opts(struct config_item *item)
846 {
847 	return container_of(to_config_group(item), struct f_rndis_opts,
848 			    func_inst.group);
849 }
850 
851 /* f_rndis_item_ops */
852 USB_ETHERNET_CONFIGFS_ITEM(rndis);
853 
854 /* f_rndis_opts_dev_addr */
855 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(rndis);
856 
857 /* f_rndis_opts_host_addr */
858 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(rndis);
859 
860 /* f_rndis_opts_qmult */
861 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(rndis);
862 
863 /* f_rndis_opts_ifname */
864 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(rndis);
865 
866 static struct configfs_attribute *rndis_attrs[] = {
867 	&rndis_opts_attr_dev_addr,
868 	&rndis_opts_attr_host_addr,
869 	&rndis_opts_attr_qmult,
870 	&rndis_opts_attr_ifname,
871 	NULL,
872 };
873 
874 static struct config_item_type rndis_func_type = {
875 	.ct_item_ops	= &rndis_item_ops,
876 	.ct_attrs	= rndis_attrs,
877 	.ct_owner	= THIS_MODULE,
878 };
879 
880 static void rndis_free_inst(struct usb_function_instance *f)
881 {
882 	struct f_rndis_opts *opts;
883 
884 	opts = container_of(f, struct f_rndis_opts, func_inst);
885 	if (!opts->borrowed_net) {
886 		if (opts->bound)
887 			gether_cleanup(netdev_priv(opts->net));
888 		else
889 			free_netdev(opts->net);
890 	}
891 
892 	kfree(opts);
893 }
894 
895 static struct usb_function_instance *rndis_alloc_inst(void)
896 {
897 	struct f_rndis_opts *opts;
898 	struct usb_os_desc *descs[1];
899 	char *names[1];
900 
901 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
902 	if (!opts)
903 		return ERR_PTR(-ENOMEM);
904 	opts->rndis_os_desc.ext_compat_id = opts->rndis_ext_compat_id;
905 
906 	mutex_init(&opts->lock);
907 	opts->func_inst.free_func_inst = rndis_free_inst;
908 	opts->net = gether_setup_default();
909 	if (IS_ERR(opts->net)) {
910 		struct net_device *net = opts->net;
911 		kfree(opts);
912 		return ERR_CAST(net);
913 	}
914 	INIT_LIST_HEAD(&opts->rndis_os_desc.ext_prop);
915 
916 	descs[0] = &opts->rndis_os_desc;
917 	names[0] = "rndis";
918 	config_group_init_type_name(&opts->func_inst.group, "",
919 				    &rndis_func_type);
920 	usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
921 				       names, THIS_MODULE);
922 
923 	return &opts->func_inst;
924 }
925 
926 static void rndis_free(struct usb_function *f)
927 {
928 	struct f_rndis *rndis;
929 	struct f_rndis_opts *opts;
930 
931 	rndis = func_to_rndis(f);
932 	rndis_deregister(rndis->params);
933 	opts = container_of(f->fi, struct f_rndis_opts, func_inst);
934 	kfree(rndis);
935 	mutex_lock(&opts->lock);
936 	opts->refcnt--;
937 	mutex_unlock(&opts->lock);
938 }
939 
940 static void rndis_unbind(struct usb_configuration *c, struct usb_function *f)
941 {
942 	struct f_rndis		*rndis = func_to_rndis(f);
943 
944 	kfree(f->os_desc_table);
945 	f->os_desc_n = 0;
946 	usb_free_all_descriptors(f);
947 
948 	kfree(rndis->notify_req->buf);
949 	usb_ep_free_request(rndis->notify, rndis->notify_req);
950 }
951 
952 static struct usb_function *rndis_alloc(struct usb_function_instance *fi)
953 {
954 	struct f_rndis	*rndis;
955 	struct f_rndis_opts *opts;
956 	struct rndis_params *params;
957 
958 	/* allocate and initialize one new instance */
959 	rndis = kzalloc(sizeof(*rndis), GFP_KERNEL);
960 	if (!rndis)
961 		return ERR_PTR(-ENOMEM);
962 
963 	opts = container_of(fi, struct f_rndis_opts, func_inst);
964 	mutex_lock(&opts->lock);
965 	opts->refcnt++;
966 
967 	gether_get_host_addr_u8(opts->net, rndis->ethaddr);
968 	rndis->vendorID = opts->vendor_id;
969 	rndis->manufacturer = opts->manufacturer;
970 
971 	rndis->port.ioport = netdev_priv(opts->net);
972 	mutex_unlock(&opts->lock);
973 	/* RNDIS activates when the host changes this filter */
974 	rndis->port.cdc_filter = 0;
975 
976 	/* RNDIS has special (and complex) framing */
977 	rndis->port.header_len = sizeof(struct rndis_packet_msg_type);
978 	rndis->port.wrap = rndis_add_header;
979 	rndis->port.unwrap = rndis_rm_hdr;
980 
981 	rndis->port.func.name = "rndis";
982 	/* descriptors are per-instance copies */
983 	rndis->port.func.bind = rndis_bind;
984 	rndis->port.func.unbind = rndis_unbind;
985 	rndis->port.func.set_alt = rndis_set_alt;
986 	rndis->port.func.setup = rndis_setup;
987 	rndis->port.func.disable = rndis_disable;
988 	rndis->port.func.free_func = rndis_free;
989 
990 	params = rndis_register(rndis_response_available, rndis);
991 	if (IS_ERR(params)) {
992 		kfree(rndis);
993 		return ERR_CAST(params);
994 	}
995 	rndis->params = params;
996 
997 	return &rndis->port.func;
998 }
999 
1000 DECLARE_USB_FUNCTION_INIT(rndis, rndis_alloc_inst, rndis_alloc);
1001 MODULE_LICENSE("GPL");
1002 MODULE_AUTHOR("David Brownell");
1003