1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * u_ether.c -- Ethernet-over-USB link layer utilities for Gadget stack
4  *
5  * Copyright (C) 2003-2005,2008 David Brownell
6  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
7  * Copyright (C) 2008 Nokia Corporation
8  */
9 
10 /* #define VERBOSE_DEBUG */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/gfp.h>
15 #include <linux/device.h>
16 #include <linux/ctype.h>
17 #include <linux/etherdevice.h>
18 #include <linux/ethtool.h>
19 #include <linux/if_vlan.h>
20 
21 #include "u_ether.h"
22 
23 
24 /*
25  * This component encapsulates the Ethernet link glue needed to provide
26  * one (!) network link through the USB gadget stack, normally "usb0".
27  *
28  * The control and data models are handled by the function driver which
29  * connects to this code; such as CDC Ethernet (ECM or EEM),
30  * "CDC Subset", or RNDIS.  That includes all descriptor and endpoint
31  * management.
32  *
33  * Link level addressing is handled by this component using module
34  * parameters; if no such parameters are provided, random link level
35  * addresses are used.  Each end of the link uses one address.  The
36  * host end address is exported in various ways, and is often recorded
37  * in configuration databases.
38  *
39  * The driver which assembles each configuration using such a link is
40  * responsible for ensuring that each configuration includes at most one
41  * instance of is network link.  (The network layer provides ways for
42  * this single "physical" link to be used by multiple virtual links.)
43  */
44 
45 #define UETH__VERSION	"29-May-2008"
46 
47 /* Experiments show that both Linux and Windows hosts allow up to 16k
48  * frame sizes. Set the max MTU size to 15k+52 to prevent allocating 32k
49  * blocks and still have efficient handling. */
50 #define GETHER_MAX_MTU_SIZE 15412
51 #define GETHER_MAX_ETH_FRAME_LEN (GETHER_MAX_MTU_SIZE + ETH_HLEN)
52 
53 struct eth_dev {
54 	/* lock is held while accessing port_usb
55 	 */
56 	spinlock_t		lock;
57 	struct gether		*port_usb;
58 
59 	struct net_device	*net;
60 	struct usb_gadget	*gadget;
61 
62 	spinlock_t		req_lock;	/* guard {rx,tx}_reqs */
63 	struct list_head	tx_reqs, rx_reqs;
64 	atomic_t		tx_qlen;
65 
66 	struct sk_buff_head	rx_frames;
67 
68 	unsigned		qmult;
69 
70 	unsigned		header_len;
71 	struct sk_buff		*(*wrap)(struct gether *, struct sk_buff *skb);
72 	int			(*unwrap)(struct gether *,
73 						struct sk_buff *skb,
74 						struct sk_buff_head *list);
75 
76 	struct work_struct	work;
77 
78 	unsigned long		todo;
79 #define	WORK_RX_MEMORY		0
80 
81 	bool			zlp;
82 	bool			no_skb_reserve;
83 	bool			ifname_set;
84 	u8			host_mac[ETH_ALEN];
85 	u8			dev_mac[ETH_ALEN];
86 };
87 
88 /*-------------------------------------------------------------------------*/
89 
90 #define RX_EXTRA	20	/* bytes guarding against rx overflows */
91 
92 #define DEFAULT_QLEN	2	/* double buffering by default */
93 
94 /* for dual-speed hardware, use deeper queues at high/super speed */
95 static inline int qlen(struct usb_gadget *gadget, unsigned qmult)
96 {
97 	if (gadget_is_dualspeed(gadget) && (gadget->speed == USB_SPEED_HIGH ||
98 					    gadget->speed >= USB_SPEED_SUPER))
99 		return qmult * DEFAULT_QLEN;
100 	else
101 		return DEFAULT_QLEN;
102 }
103 
104 /*-------------------------------------------------------------------------*/
105 
106 /* REVISIT there must be a better way than having two sets
107  * of debug calls ...
108  */
109 
110 #undef DBG
111 #undef VDBG
112 #undef ERROR
113 #undef INFO
114 
115 #define xprintk(d, level, fmt, args...) \
116 	printk(level "%s: " fmt , (d)->net->name , ## args)
117 
118 #ifdef DEBUG
119 #undef DEBUG
120 #define DBG(dev, fmt, args...) \
121 	xprintk(dev , KERN_DEBUG , fmt , ## args)
122 #else
123 #define DBG(dev, fmt, args...) \
124 	do { } while (0)
125 #endif /* DEBUG */
126 
127 #ifdef VERBOSE_DEBUG
128 #define VDBG	DBG
129 #else
130 #define VDBG(dev, fmt, args...) \
131 	do { } while (0)
132 #endif /* DEBUG */
133 
134 #define ERROR(dev, fmt, args...) \
135 	xprintk(dev , KERN_ERR , fmt , ## args)
136 #define INFO(dev, fmt, args...) \
137 	xprintk(dev , KERN_INFO , fmt , ## args)
138 
139 /*-------------------------------------------------------------------------*/
140 
141 /* NETWORK DRIVER HOOKUP (to the layer above this driver) */
142 
143 static void eth_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *p)
144 {
145 	struct eth_dev *dev = netdev_priv(net);
146 
147 	strlcpy(p->driver, "g_ether", sizeof(p->driver));
148 	strlcpy(p->version, UETH__VERSION, sizeof(p->version));
149 	strlcpy(p->fw_version, dev->gadget->name, sizeof(p->fw_version));
150 	strlcpy(p->bus_info, dev_name(&dev->gadget->dev), sizeof(p->bus_info));
151 }
152 
153 /* REVISIT can also support:
154  *   - WOL (by tracking suspends and issuing remote wakeup)
155  *   - msglevel (implies updated messaging)
156  *   - ... probably more ethtool ops
157  */
158 
159 static const struct ethtool_ops ops = {
160 	.get_drvinfo = eth_get_drvinfo,
161 	.get_link = ethtool_op_get_link,
162 };
163 
164 static void defer_kevent(struct eth_dev *dev, int flag)
165 {
166 	if (test_and_set_bit(flag, &dev->todo))
167 		return;
168 	if (!schedule_work(&dev->work))
169 		ERROR(dev, "kevent %d may have been dropped\n", flag);
170 	else
171 		DBG(dev, "kevent %d scheduled\n", flag);
172 }
173 
174 static void rx_complete(struct usb_ep *ep, struct usb_request *req);
175 
176 static int
177 rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
178 {
179 	struct usb_gadget *g = dev->gadget;
180 	struct sk_buff	*skb;
181 	int		retval = -ENOMEM;
182 	size_t		size = 0;
183 	struct usb_ep	*out;
184 	unsigned long	flags;
185 
186 	spin_lock_irqsave(&dev->lock, flags);
187 	if (dev->port_usb)
188 		out = dev->port_usb->out_ep;
189 	else
190 		out = NULL;
191 
192 	if (!out)
193 	{
194 		spin_unlock_irqrestore(&dev->lock, flags);
195 		return -ENOTCONN;
196 	}
197 
198 	/* Padding up to RX_EXTRA handles minor disagreements with host.
199 	 * Normally we use the USB "terminate on short read" convention;
200 	 * so allow up to (N*maxpacket), since that memory is normally
201 	 * already allocated.  Some hardware doesn't deal well with short
202 	 * reads (e.g. DMA must be N*maxpacket), so for now don't trim a
203 	 * byte off the end (to force hardware errors on overflow).
204 	 *
205 	 * RNDIS uses internal framing, and explicitly allows senders to
206 	 * pad to end-of-packet.  That's potentially nice for speed, but
207 	 * means receivers can't recover lost synch on their own (because
208 	 * new packets don't only start after a short RX).
209 	 */
210 	size += sizeof(struct ethhdr) + dev->net->mtu + RX_EXTRA;
211 	size += dev->port_usb->header_len;
212 
213 	if (g->quirk_ep_out_aligned_size) {
214 		size += out->maxpacket - 1;
215 		size -= size % out->maxpacket;
216 	}
217 
218 	if (dev->port_usb->is_fixed)
219 		size = max_t(size_t, size, dev->port_usb->fixed_out_len);
220 	spin_unlock_irqrestore(&dev->lock, flags);
221 
222 	skb = __netdev_alloc_skb(dev->net, size + NET_IP_ALIGN, gfp_flags);
223 	if (skb == NULL) {
224 		DBG(dev, "no rx skb\n");
225 		goto enomem;
226 	}
227 
228 	/* Some platforms perform better when IP packets are aligned,
229 	 * but on at least one, checksumming fails otherwise.  Note:
230 	 * RNDIS headers involve variable numbers of LE32 values.
231 	 */
232 	if (likely(!dev->no_skb_reserve))
233 		skb_reserve(skb, NET_IP_ALIGN);
234 
235 	req->buf = skb->data;
236 	req->length = size;
237 	req->complete = rx_complete;
238 	req->context = skb;
239 
240 	retval = usb_ep_queue(out, req, gfp_flags);
241 	if (retval == -ENOMEM)
242 enomem:
243 		defer_kevent(dev, WORK_RX_MEMORY);
244 	if (retval) {
245 		DBG(dev, "rx submit --> %d\n", retval);
246 		if (skb)
247 			dev_kfree_skb_any(skb);
248 		spin_lock_irqsave(&dev->req_lock, flags);
249 		list_add(&req->list, &dev->rx_reqs);
250 		spin_unlock_irqrestore(&dev->req_lock, flags);
251 	}
252 	return retval;
253 }
254 
255 static void rx_complete(struct usb_ep *ep, struct usb_request *req)
256 {
257 	struct sk_buff	*skb = req->context, *skb2;
258 	struct eth_dev	*dev = ep->driver_data;
259 	int		status = req->status;
260 
261 	switch (status) {
262 
263 	/* normal completion */
264 	case 0:
265 		skb_put(skb, req->actual);
266 
267 		if (dev->unwrap) {
268 			unsigned long	flags;
269 
270 			spin_lock_irqsave(&dev->lock, flags);
271 			if (dev->port_usb) {
272 				status = dev->unwrap(dev->port_usb,
273 							skb,
274 							&dev->rx_frames);
275 			} else {
276 				dev_kfree_skb_any(skb);
277 				status = -ENOTCONN;
278 			}
279 			spin_unlock_irqrestore(&dev->lock, flags);
280 		} else {
281 			skb_queue_tail(&dev->rx_frames, skb);
282 		}
283 		skb = NULL;
284 
285 		skb2 = skb_dequeue(&dev->rx_frames);
286 		while (skb2) {
287 			if (status < 0
288 					|| ETH_HLEN > skb2->len
289 					|| skb2->len > GETHER_MAX_ETH_FRAME_LEN) {
290 				dev->net->stats.rx_errors++;
291 				dev->net->stats.rx_length_errors++;
292 				DBG(dev, "rx length %d\n", skb2->len);
293 				dev_kfree_skb_any(skb2);
294 				goto next_frame;
295 			}
296 			skb2->protocol = eth_type_trans(skb2, dev->net);
297 			dev->net->stats.rx_packets++;
298 			dev->net->stats.rx_bytes += skb2->len;
299 
300 			/* no buffer copies needed, unless hardware can't
301 			 * use skb buffers.
302 			 */
303 			status = netif_rx(skb2);
304 next_frame:
305 			skb2 = skb_dequeue(&dev->rx_frames);
306 		}
307 		break;
308 
309 	/* software-driven interface shutdown */
310 	case -ECONNRESET:		/* unlink */
311 	case -ESHUTDOWN:		/* disconnect etc */
312 		VDBG(dev, "rx shutdown, code %d\n", status);
313 		goto quiesce;
314 
315 	/* for hardware automagic (such as pxa) */
316 	case -ECONNABORTED:		/* endpoint reset */
317 		DBG(dev, "rx %s reset\n", ep->name);
318 		defer_kevent(dev, WORK_RX_MEMORY);
319 quiesce:
320 		dev_kfree_skb_any(skb);
321 		goto clean;
322 
323 	/* data overrun */
324 	case -EOVERFLOW:
325 		dev->net->stats.rx_over_errors++;
326 		fallthrough;
327 
328 	default:
329 		dev->net->stats.rx_errors++;
330 		DBG(dev, "rx status %d\n", status);
331 		break;
332 	}
333 
334 	if (skb)
335 		dev_kfree_skb_any(skb);
336 	if (!netif_running(dev->net)) {
337 clean:
338 		spin_lock(&dev->req_lock);
339 		list_add(&req->list, &dev->rx_reqs);
340 		spin_unlock(&dev->req_lock);
341 		req = NULL;
342 	}
343 	if (req)
344 		rx_submit(dev, req, GFP_ATOMIC);
345 }
346 
347 static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
348 {
349 	unsigned		i;
350 	struct usb_request	*req;
351 
352 	if (!n)
353 		return -ENOMEM;
354 
355 	/* queue/recycle up to N requests */
356 	i = n;
357 	list_for_each_entry(req, list, list) {
358 		if (i-- == 0)
359 			goto extra;
360 	}
361 	while (i--) {
362 		req = usb_ep_alloc_request(ep, GFP_ATOMIC);
363 		if (!req)
364 			return list_empty(list) ? -ENOMEM : 0;
365 		list_add(&req->list, list);
366 	}
367 	return 0;
368 
369 extra:
370 	/* free extras */
371 	for (;;) {
372 		struct list_head	*next;
373 
374 		next = req->list.next;
375 		list_del(&req->list);
376 		usb_ep_free_request(ep, req);
377 
378 		if (next == list)
379 			break;
380 
381 		req = container_of(next, struct usb_request, list);
382 	}
383 	return 0;
384 }
385 
386 static int alloc_requests(struct eth_dev *dev, struct gether *link, unsigned n)
387 {
388 	int	status;
389 
390 	spin_lock(&dev->req_lock);
391 	status = prealloc(&dev->tx_reqs, link->in_ep, n);
392 	if (status < 0)
393 		goto fail;
394 	status = prealloc(&dev->rx_reqs, link->out_ep, n);
395 	if (status < 0)
396 		goto fail;
397 	goto done;
398 fail:
399 	DBG(dev, "can't alloc requests\n");
400 done:
401 	spin_unlock(&dev->req_lock);
402 	return status;
403 }
404 
405 static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
406 {
407 	struct usb_request	*req;
408 	unsigned long		flags;
409 
410 	/* fill unused rxq slots with some skb */
411 	spin_lock_irqsave(&dev->req_lock, flags);
412 	while (!list_empty(&dev->rx_reqs)) {
413 		req = list_first_entry(&dev->rx_reqs, struct usb_request, list);
414 		list_del_init(&req->list);
415 		spin_unlock_irqrestore(&dev->req_lock, flags);
416 
417 		if (rx_submit(dev, req, gfp_flags) < 0) {
418 			defer_kevent(dev, WORK_RX_MEMORY);
419 			return;
420 		}
421 
422 		spin_lock_irqsave(&dev->req_lock, flags);
423 	}
424 	spin_unlock_irqrestore(&dev->req_lock, flags);
425 }
426 
427 static void eth_work(struct work_struct *work)
428 {
429 	struct eth_dev	*dev = container_of(work, struct eth_dev, work);
430 
431 	if (test_and_clear_bit(WORK_RX_MEMORY, &dev->todo)) {
432 		if (netif_running(dev->net))
433 			rx_fill(dev, GFP_KERNEL);
434 	}
435 
436 	if (dev->todo)
437 		DBG(dev, "work done, flags = 0x%lx\n", dev->todo);
438 }
439 
440 static void tx_complete(struct usb_ep *ep, struct usb_request *req)
441 {
442 	struct sk_buff	*skb = req->context;
443 	struct eth_dev	*dev = ep->driver_data;
444 
445 	switch (req->status) {
446 	default:
447 		dev->net->stats.tx_errors++;
448 		VDBG(dev, "tx err %d\n", req->status);
449 		fallthrough;
450 	case -ECONNRESET:		/* unlink */
451 	case -ESHUTDOWN:		/* disconnect etc */
452 		dev_kfree_skb_any(skb);
453 		break;
454 	case 0:
455 		dev->net->stats.tx_bytes += skb->len;
456 		dev_consume_skb_any(skb);
457 	}
458 	dev->net->stats.tx_packets++;
459 
460 	spin_lock(&dev->req_lock);
461 	list_add(&req->list, &dev->tx_reqs);
462 	spin_unlock(&dev->req_lock);
463 
464 	atomic_dec(&dev->tx_qlen);
465 	if (netif_carrier_ok(dev->net))
466 		netif_wake_queue(dev->net);
467 }
468 
469 static inline int is_promisc(u16 cdc_filter)
470 {
471 	return cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
472 }
473 
474 static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
475 					struct net_device *net)
476 {
477 	struct eth_dev		*dev = netdev_priv(net);
478 	int			length = 0;
479 	int			retval;
480 	struct usb_request	*req = NULL;
481 	unsigned long		flags;
482 	struct usb_ep		*in;
483 	u16			cdc_filter;
484 
485 	spin_lock_irqsave(&dev->lock, flags);
486 	if (dev->port_usb) {
487 		in = dev->port_usb->in_ep;
488 		cdc_filter = dev->port_usb->cdc_filter;
489 	} else {
490 		in = NULL;
491 		cdc_filter = 0;
492 	}
493 	spin_unlock_irqrestore(&dev->lock, flags);
494 
495 	if (!in) {
496 		if (skb)
497 			dev_kfree_skb_any(skb);
498 		return NETDEV_TX_OK;
499 	}
500 
501 	/* apply outgoing CDC or RNDIS filters */
502 	if (skb && !is_promisc(cdc_filter)) {
503 		u8		*dest = skb->data;
504 
505 		if (is_multicast_ether_addr(dest)) {
506 			u16	type;
507 
508 			/* ignores USB_CDC_PACKET_TYPE_MULTICAST and host
509 			 * SET_ETHERNET_MULTICAST_FILTERS requests
510 			 */
511 			if (is_broadcast_ether_addr(dest))
512 				type = USB_CDC_PACKET_TYPE_BROADCAST;
513 			else
514 				type = USB_CDC_PACKET_TYPE_ALL_MULTICAST;
515 			if (!(cdc_filter & type)) {
516 				dev_kfree_skb_any(skb);
517 				return NETDEV_TX_OK;
518 			}
519 		}
520 		/* ignores USB_CDC_PACKET_TYPE_DIRECTED */
521 	}
522 
523 	spin_lock_irqsave(&dev->req_lock, flags);
524 	/*
525 	 * this freelist can be empty if an interrupt triggered disconnect()
526 	 * and reconfigured the gadget (shutting down this queue) after the
527 	 * network stack decided to xmit but before we got the spinlock.
528 	 */
529 	if (list_empty(&dev->tx_reqs)) {
530 		spin_unlock_irqrestore(&dev->req_lock, flags);
531 		return NETDEV_TX_BUSY;
532 	}
533 
534 	req = list_first_entry(&dev->tx_reqs, struct usb_request, list);
535 	list_del(&req->list);
536 
537 	/* temporarily stop TX queue when the freelist empties */
538 	if (list_empty(&dev->tx_reqs))
539 		netif_stop_queue(net);
540 	spin_unlock_irqrestore(&dev->req_lock, flags);
541 
542 	/* no buffer copies needed, unless the network stack did it
543 	 * or the hardware can't use skb buffers.
544 	 * or there's not enough space for extra headers we need
545 	 */
546 	if (dev->wrap) {
547 		unsigned long	flags;
548 
549 		spin_lock_irqsave(&dev->lock, flags);
550 		if (dev->port_usb)
551 			skb = dev->wrap(dev->port_usb, skb);
552 		spin_unlock_irqrestore(&dev->lock, flags);
553 		if (!skb) {
554 			/* Multi frame CDC protocols may store the frame for
555 			 * later which is not a dropped frame.
556 			 */
557 			if (dev->port_usb &&
558 					dev->port_usb->supports_multi_frame)
559 				goto multiframe;
560 			goto drop;
561 		}
562 	}
563 
564 	length = skb->len;
565 	req->buf = skb->data;
566 	req->context = skb;
567 	req->complete = tx_complete;
568 
569 	/* NCM requires no zlp if transfer is dwNtbInMaxSize */
570 	if (dev->port_usb &&
571 	    dev->port_usb->is_fixed &&
572 	    length == dev->port_usb->fixed_in_len &&
573 	    (length % in->maxpacket) == 0)
574 		req->zero = 0;
575 	else
576 		req->zero = 1;
577 
578 	/* use zlp framing on tx for strict CDC-Ether conformance,
579 	 * though any robust network rx path ignores extra padding.
580 	 * and some hardware doesn't like to write zlps.
581 	 */
582 	if (req->zero && !dev->zlp && (length % in->maxpacket) == 0)
583 		length++;
584 
585 	req->length = length;
586 
587 	retval = usb_ep_queue(in, req, GFP_ATOMIC);
588 	switch (retval) {
589 	default:
590 		DBG(dev, "tx queue err %d\n", retval);
591 		break;
592 	case 0:
593 		netif_trans_update(net);
594 		atomic_inc(&dev->tx_qlen);
595 	}
596 
597 	if (retval) {
598 		dev_kfree_skb_any(skb);
599 drop:
600 		dev->net->stats.tx_dropped++;
601 multiframe:
602 		spin_lock_irqsave(&dev->req_lock, flags);
603 		if (list_empty(&dev->tx_reqs))
604 			netif_start_queue(net);
605 		list_add(&req->list, &dev->tx_reqs);
606 		spin_unlock_irqrestore(&dev->req_lock, flags);
607 	}
608 	return NETDEV_TX_OK;
609 }
610 
611 /*-------------------------------------------------------------------------*/
612 
613 static void eth_start(struct eth_dev *dev, gfp_t gfp_flags)
614 {
615 	DBG(dev, "%s\n", __func__);
616 
617 	/* fill the rx queue */
618 	rx_fill(dev, gfp_flags);
619 
620 	/* and open the tx floodgates */
621 	atomic_set(&dev->tx_qlen, 0);
622 	netif_wake_queue(dev->net);
623 }
624 
625 static int eth_open(struct net_device *net)
626 {
627 	struct eth_dev	*dev = netdev_priv(net);
628 	struct gether	*link;
629 
630 	DBG(dev, "%s\n", __func__);
631 	if (netif_carrier_ok(dev->net))
632 		eth_start(dev, GFP_KERNEL);
633 
634 	spin_lock_irq(&dev->lock);
635 	link = dev->port_usb;
636 	if (link && link->open)
637 		link->open(link);
638 	spin_unlock_irq(&dev->lock);
639 
640 	return 0;
641 }
642 
643 static int eth_stop(struct net_device *net)
644 {
645 	struct eth_dev	*dev = netdev_priv(net);
646 	unsigned long	flags;
647 
648 	VDBG(dev, "%s\n", __func__);
649 	netif_stop_queue(net);
650 
651 	DBG(dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
652 		dev->net->stats.rx_packets, dev->net->stats.tx_packets,
653 		dev->net->stats.rx_errors, dev->net->stats.tx_errors
654 		);
655 
656 	/* ensure there are no more active requests */
657 	spin_lock_irqsave(&dev->lock, flags);
658 	if (dev->port_usb) {
659 		struct gether	*link = dev->port_usb;
660 		const struct usb_endpoint_descriptor *in;
661 		const struct usb_endpoint_descriptor *out;
662 
663 		if (link->close)
664 			link->close(link);
665 
666 		/* NOTE:  we have no abort-queue primitive we could use
667 		 * to cancel all pending I/O.  Instead, we disable then
668 		 * reenable the endpoints ... this idiom may leave toggle
669 		 * wrong, but that's a self-correcting error.
670 		 *
671 		 * REVISIT:  we *COULD* just let the transfers complete at
672 		 * their own pace; the network stack can handle old packets.
673 		 * For the moment we leave this here, since it works.
674 		 */
675 		in = link->in_ep->desc;
676 		out = link->out_ep->desc;
677 		usb_ep_disable(link->in_ep);
678 		usb_ep_disable(link->out_ep);
679 		if (netif_carrier_ok(net)) {
680 			DBG(dev, "host still using in/out endpoints\n");
681 			link->in_ep->desc = in;
682 			link->out_ep->desc = out;
683 			usb_ep_enable(link->in_ep);
684 			usb_ep_enable(link->out_ep);
685 		}
686 	}
687 	spin_unlock_irqrestore(&dev->lock, flags);
688 
689 	return 0;
690 }
691 
692 /*-------------------------------------------------------------------------*/
693 
694 static int get_ether_addr(const char *str, u8 *dev_addr)
695 {
696 	if (str) {
697 		unsigned	i;
698 
699 		for (i = 0; i < 6; i++) {
700 			unsigned char num;
701 
702 			if ((*str == '.') || (*str == ':'))
703 				str++;
704 			num = hex_to_bin(*str++) << 4;
705 			num |= hex_to_bin(*str++);
706 			dev_addr [i] = num;
707 		}
708 		if (is_valid_ether_addr(dev_addr))
709 			return 0;
710 	}
711 	eth_random_addr(dev_addr);
712 	return 1;
713 }
714 
715 static int get_ether_addr_str(u8 dev_addr[ETH_ALEN], char *str, int len)
716 {
717 	if (len < 18)
718 		return -EINVAL;
719 
720 	snprintf(str, len, "%pM", dev_addr);
721 	return 18;
722 }
723 
724 static const struct net_device_ops eth_netdev_ops = {
725 	.ndo_open		= eth_open,
726 	.ndo_stop		= eth_stop,
727 	.ndo_start_xmit		= eth_start_xmit,
728 	.ndo_set_mac_address 	= eth_mac_addr,
729 	.ndo_validate_addr	= eth_validate_addr,
730 };
731 
732 static struct device_type gadget_type = {
733 	.name	= "gadget",
734 };
735 
736 /*
737  * gether_setup_name - initialize one ethernet-over-usb link
738  * @g: gadget to associated with these links
739  * @ethaddr: NULL, or a buffer in which the ethernet address of the
740  *	host side of the link is recorded
741  * @netname: name for network device (for example, "usb")
742  * Context: may sleep
743  *
744  * This sets up the single network link that may be exported by a
745  * gadget driver using this framework.  The link layer addresses are
746  * set up using module parameters.
747  *
748  * Returns an eth_dev pointer on success, or an ERR_PTR on failure.
749  */
750 struct eth_dev *gether_setup_name(struct usb_gadget *g,
751 		const char *dev_addr, const char *host_addr,
752 		u8 ethaddr[ETH_ALEN], unsigned qmult, const char *netname)
753 {
754 	struct eth_dev		*dev;
755 	struct net_device	*net;
756 	int			status;
757 
758 	net = alloc_etherdev(sizeof *dev);
759 	if (!net)
760 		return ERR_PTR(-ENOMEM);
761 
762 	dev = netdev_priv(net);
763 	spin_lock_init(&dev->lock);
764 	spin_lock_init(&dev->req_lock);
765 	INIT_WORK(&dev->work, eth_work);
766 	INIT_LIST_HEAD(&dev->tx_reqs);
767 	INIT_LIST_HEAD(&dev->rx_reqs);
768 
769 	skb_queue_head_init(&dev->rx_frames);
770 
771 	/* network device setup */
772 	dev->net = net;
773 	dev->qmult = qmult;
774 	snprintf(net->name, sizeof(net->name), "%s%%d", netname);
775 
776 	if (get_ether_addr(dev_addr, net->dev_addr))
777 		dev_warn(&g->dev,
778 			"using random %s ethernet address\n", "self");
779 	if (get_ether_addr(host_addr, dev->host_mac))
780 		dev_warn(&g->dev,
781 			"using random %s ethernet address\n", "host");
782 
783 	if (ethaddr)
784 		memcpy(ethaddr, dev->host_mac, ETH_ALEN);
785 
786 	net->netdev_ops = &eth_netdev_ops;
787 
788 	net->ethtool_ops = &ops;
789 
790 	/* MTU range: 14 - 15412 */
791 	net->min_mtu = ETH_HLEN;
792 	net->max_mtu = GETHER_MAX_MTU_SIZE;
793 
794 	dev->gadget = g;
795 	SET_NETDEV_DEV(net, &g->dev);
796 	SET_NETDEV_DEVTYPE(net, &gadget_type);
797 
798 	status = register_netdev(net);
799 	if (status < 0) {
800 		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
801 		free_netdev(net);
802 		dev = ERR_PTR(status);
803 	} else {
804 		INFO(dev, "MAC %pM\n", net->dev_addr);
805 		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
806 
807 		/*
808 		 * two kinds of host-initiated state changes:
809 		 *  - iff DATA transfer is active, carrier is "on"
810 		 *  - tx queueing enabled if open *and* carrier is "on"
811 		 */
812 		netif_carrier_off(net);
813 	}
814 
815 	return dev;
816 }
817 EXPORT_SYMBOL_GPL(gether_setup_name);
818 
819 struct net_device *gether_setup_name_default(const char *netname)
820 {
821 	struct net_device	*net;
822 	struct eth_dev		*dev;
823 
824 	net = alloc_etherdev(sizeof(*dev));
825 	if (!net)
826 		return ERR_PTR(-ENOMEM);
827 
828 	dev = netdev_priv(net);
829 	spin_lock_init(&dev->lock);
830 	spin_lock_init(&dev->req_lock);
831 	INIT_WORK(&dev->work, eth_work);
832 	INIT_LIST_HEAD(&dev->tx_reqs);
833 	INIT_LIST_HEAD(&dev->rx_reqs);
834 
835 	skb_queue_head_init(&dev->rx_frames);
836 
837 	/* network device setup */
838 	dev->net = net;
839 	dev->qmult = QMULT_DEFAULT;
840 	snprintf(net->name, sizeof(net->name), "%s%%d", netname);
841 
842 	eth_random_addr(dev->dev_mac);
843 	pr_warn("using random %s ethernet address\n", "self");
844 	eth_random_addr(dev->host_mac);
845 	pr_warn("using random %s ethernet address\n", "host");
846 
847 	net->netdev_ops = &eth_netdev_ops;
848 
849 	net->ethtool_ops = &ops;
850 	SET_NETDEV_DEVTYPE(net, &gadget_type);
851 
852 	/* MTU range: 14 - 15412 */
853 	net->min_mtu = ETH_HLEN;
854 	net->max_mtu = GETHER_MAX_MTU_SIZE;
855 
856 	return net;
857 }
858 EXPORT_SYMBOL_GPL(gether_setup_name_default);
859 
860 int gether_register_netdev(struct net_device *net)
861 {
862 	struct eth_dev *dev;
863 	struct usb_gadget *g;
864 	struct sockaddr sa;
865 	int status;
866 
867 	if (!net->dev.parent)
868 		return -EINVAL;
869 	dev = netdev_priv(net);
870 	g = dev->gadget;
871 	status = register_netdev(net);
872 	if (status < 0) {
873 		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
874 		return status;
875 	} else {
876 		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
877 
878 		/* two kinds of host-initiated state changes:
879 		 *  - iff DATA transfer is active, carrier is "on"
880 		 *  - tx queueing enabled if open *and* carrier is "on"
881 		 */
882 		netif_carrier_off(net);
883 	}
884 	sa.sa_family = net->type;
885 	memcpy(sa.sa_data, dev->dev_mac, ETH_ALEN);
886 	rtnl_lock();
887 	status = dev_set_mac_address(net, &sa, NULL);
888 	rtnl_unlock();
889 	if (status)
890 		pr_warn("cannot set self ethernet address: %d\n", status);
891 	else
892 		INFO(dev, "MAC %pM\n", dev->dev_mac);
893 
894 	return status;
895 }
896 EXPORT_SYMBOL_GPL(gether_register_netdev);
897 
898 void gether_set_gadget(struct net_device *net, struct usb_gadget *g)
899 {
900 	struct eth_dev *dev;
901 
902 	dev = netdev_priv(net);
903 	dev->gadget = g;
904 	SET_NETDEV_DEV(net, &g->dev);
905 }
906 EXPORT_SYMBOL_GPL(gether_set_gadget);
907 
908 int gether_set_dev_addr(struct net_device *net, const char *dev_addr)
909 {
910 	struct eth_dev *dev;
911 	u8 new_addr[ETH_ALEN];
912 
913 	dev = netdev_priv(net);
914 	if (get_ether_addr(dev_addr, new_addr))
915 		return -EINVAL;
916 	memcpy(dev->dev_mac, new_addr, ETH_ALEN);
917 	return 0;
918 }
919 EXPORT_SYMBOL_GPL(gether_set_dev_addr);
920 
921 int gether_get_dev_addr(struct net_device *net, char *dev_addr, int len)
922 {
923 	struct eth_dev *dev;
924 	int ret;
925 
926 	dev = netdev_priv(net);
927 	ret = get_ether_addr_str(dev->dev_mac, dev_addr, len);
928 	if (ret + 1 < len) {
929 		dev_addr[ret++] = '\n';
930 		dev_addr[ret] = '\0';
931 	}
932 
933 	return ret;
934 }
935 EXPORT_SYMBOL_GPL(gether_get_dev_addr);
936 
937 int gether_set_host_addr(struct net_device *net, const char *host_addr)
938 {
939 	struct eth_dev *dev;
940 	u8 new_addr[ETH_ALEN];
941 
942 	dev = netdev_priv(net);
943 	if (get_ether_addr(host_addr, new_addr))
944 		return -EINVAL;
945 	memcpy(dev->host_mac, new_addr, ETH_ALEN);
946 	return 0;
947 }
948 EXPORT_SYMBOL_GPL(gether_set_host_addr);
949 
950 int gether_get_host_addr(struct net_device *net, char *host_addr, int len)
951 {
952 	struct eth_dev *dev;
953 	int ret;
954 
955 	dev = netdev_priv(net);
956 	ret = get_ether_addr_str(dev->host_mac, host_addr, len);
957 	if (ret + 1 < len) {
958 		host_addr[ret++] = '\n';
959 		host_addr[ret] = '\0';
960 	}
961 
962 	return ret;
963 }
964 EXPORT_SYMBOL_GPL(gether_get_host_addr);
965 
966 int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
967 {
968 	struct eth_dev *dev;
969 
970 	if (len < 13)
971 		return -EINVAL;
972 
973 	dev = netdev_priv(net);
974 	snprintf(host_addr, len, "%pm", dev->host_mac);
975 
976 	return strlen(host_addr);
977 }
978 EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
979 
980 void gether_get_host_addr_u8(struct net_device *net, u8 host_mac[ETH_ALEN])
981 {
982 	struct eth_dev *dev;
983 
984 	dev = netdev_priv(net);
985 	memcpy(host_mac, dev->host_mac, ETH_ALEN);
986 }
987 EXPORT_SYMBOL_GPL(gether_get_host_addr_u8);
988 
989 void gether_set_qmult(struct net_device *net, unsigned qmult)
990 {
991 	struct eth_dev *dev;
992 
993 	dev = netdev_priv(net);
994 	dev->qmult = qmult;
995 }
996 EXPORT_SYMBOL_GPL(gether_set_qmult);
997 
998 unsigned gether_get_qmult(struct net_device *net)
999 {
1000 	struct eth_dev *dev;
1001 
1002 	dev = netdev_priv(net);
1003 	return dev->qmult;
1004 }
1005 EXPORT_SYMBOL_GPL(gether_get_qmult);
1006 
1007 int gether_get_ifname(struct net_device *net, char *name, int len)
1008 {
1009 	struct eth_dev *dev = netdev_priv(net);
1010 	int ret;
1011 
1012 	rtnl_lock();
1013 	ret = scnprintf(name, len, "%s\n",
1014 			dev->ifname_set ? net->name : netdev_name(net));
1015 	rtnl_unlock();
1016 	return ret;
1017 }
1018 EXPORT_SYMBOL_GPL(gether_get_ifname);
1019 
1020 int gether_set_ifname(struct net_device *net, const char *name, int len)
1021 {
1022 	struct eth_dev *dev = netdev_priv(net);
1023 	char tmp[IFNAMSIZ];
1024 	const char *p;
1025 
1026 	if (name[len - 1] == '\n')
1027 		len--;
1028 
1029 	if (len >= sizeof(tmp))
1030 		return -E2BIG;
1031 
1032 	strscpy(tmp, name, len + 1);
1033 	if (!dev_valid_name(tmp))
1034 		return -EINVAL;
1035 
1036 	/* Require exactly one %d, so binding will not fail with EEXIST. */
1037 	p = strchr(name, '%');
1038 	if (!p || p[1] != 'd' || strchr(p + 2, '%'))
1039 		return -EINVAL;
1040 
1041 	strncpy(net->name, tmp, sizeof(net->name));
1042 	dev->ifname_set = true;
1043 
1044 	return 0;
1045 }
1046 EXPORT_SYMBOL_GPL(gether_set_ifname);
1047 
1048 /*
1049  * gether_cleanup - remove Ethernet-over-USB device
1050  * Context: may sleep
1051  *
1052  * This is called to free all resources allocated by @gether_setup().
1053  */
1054 void gether_cleanup(struct eth_dev *dev)
1055 {
1056 	if (!dev)
1057 		return;
1058 
1059 	unregister_netdev(dev->net);
1060 	flush_work(&dev->work);
1061 	free_netdev(dev->net);
1062 }
1063 EXPORT_SYMBOL_GPL(gether_cleanup);
1064 
1065 /**
1066  * gether_connect - notify network layer that USB link is active
1067  * @link: the USB link, set up with endpoints, descriptors matching
1068  *	current device speed, and any framing wrapper(s) set up.
1069  * Context: irqs blocked
1070  *
1071  * This is called to activate endpoints and let the network layer know
1072  * the connection is active ("carrier detect").  It may cause the I/O
1073  * queues to open and start letting network packets flow, but will in
1074  * any case activate the endpoints so that they respond properly to the
1075  * USB host.
1076  *
1077  * Verify net_device pointer returned using IS_ERR().  If it doesn't
1078  * indicate some error code (negative errno), ep->driver_data values
1079  * have been overwritten.
1080  */
1081 struct net_device *gether_connect(struct gether *link)
1082 {
1083 	struct eth_dev		*dev = link->ioport;
1084 	int			result = 0;
1085 
1086 	if (!dev)
1087 		return ERR_PTR(-EINVAL);
1088 
1089 	link->in_ep->driver_data = dev;
1090 	result = usb_ep_enable(link->in_ep);
1091 	if (result != 0) {
1092 		DBG(dev, "enable %s --> %d\n",
1093 			link->in_ep->name, result);
1094 		goto fail0;
1095 	}
1096 
1097 	link->out_ep->driver_data = dev;
1098 	result = usb_ep_enable(link->out_ep);
1099 	if (result != 0) {
1100 		DBG(dev, "enable %s --> %d\n",
1101 			link->out_ep->name, result);
1102 		goto fail1;
1103 	}
1104 
1105 	if (result == 0)
1106 		result = alloc_requests(dev, link, qlen(dev->gadget,
1107 					dev->qmult));
1108 
1109 	if (result == 0) {
1110 		dev->zlp = link->is_zlp_ok;
1111 		dev->no_skb_reserve = gadget_avoids_skb_reserve(dev->gadget);
1112 		DBG(dev, "qlen %d\n", qlen(dev->gadget, dev->qmult));
1113 
1114 		dev->header_len = link->header_len;
1115 		dev->unwrap = link->unwrap;
1116 		dev->wrap = link->wrap;
1117 
1118 		spin_lock(&dev->lock);
1119 		dev->port_usb = link;
1120 		if (netif_running(dev->net)) {
1121 			if (link->open)
1122 				link->open(link);
1123 		} else {
1124 			if (link->close)
1125 				link->close(link);
1126 		}
1127 		spin_unlock(&dev->lock);
1128 
1129 		netif_carrier_on(dev->net);
1130 		if (netif_running(dev->net))
1131 			eth_start(dev, GFP_ATOMIC);
1132 
1133 	/* on error, disable any endpoints  */
1134 	} else {
1135 		(void) usb_ep_disable(link->out_ep);
1136 fail1:
1137 		(void) usb_ep_disable(link->in_ep);
1138 	}
1139 fail0:
1140 	/* caller is responsible for cleanup on error */
1141 	if (result < 0)
1142 		return ERR_PTR(result);
1143 	return dev->net;
1144 }
1145 EXPORT_SYMBOL_GPL(gether_connect);
1146 
1147 /**
1148  * gether_disconnect - notify network layer that USB link is inactive
1149  * @link: the USB link, on which gether_connect() was called
1150  * Context: irqs blocked
1151  *
1152  * This is called to deactivate endpoints and let the network layer know
1153  * the connection went inactive ("no carrier").
1154  *
1155  * On return, the state is as if gether_connect() had never been called.
1156  * The endpoints are inactive, and accordingly without active USB I/O.
1157  * Pointers to endpoint descriptors and endpoint private data are nulled.
1158  */
1159 void gether_disconnect(struct gether *link)
1160 {
1161 	struct eth_dev		*dev = link->ioport;
1162 	struct usb_request	*req;
1163 
1164 	WARN_ON(!dev);
1165 	if (!dev)
1166 		return;
1167 
1168 	DBG(dev, "%s\n", __func__);
1169 
1170 	netif_stop_queue(dev->net);
1171 	netif_carrier_off(dev->net);
1172 
1173 	/* disable endpoints, forcing (synchronous) completion
1174 	 * of all pending i/o.  then free the request objects
1175 	 * and forget about the endpoints.
1176 	 */
1177 	usb_ep_disable(link->in_ep);
1178 	spin_lock(&dev->req_lock);
1179 	while (!list_empty(&dev->tx_reqs)) {
1180 		req = list_first_entry(&dev->tx_reqs, struct usb_request, list);
1181 		list_del(&req->list);
1182 
1183 		spin_unlock(&dev->req_lock);
1184 		usb_ep_free_request(link->in_ep, req);
1185 		spin_lock(&dev->req_lock);
1186 	}
1187 	spin_unlock(&dev->req_lock);
1188 	link->in_ep->desc = NULL;
1189 
1190 	usb_ep_disable(link->out_ep);
1191 	spin_lock(&dev->req_lock);
1192 	while (!list_empty(&dev->rx_reqs)) {
1193 		req = list_first_entry(&dev->rx_reqs, struct usb_request, list);
1194 		list_del(&req->list);
1195 
1196 		spin_unlock(&dev->req_lock);
1197 		usb_ep_free_request(link->out_ep, req);
1198 		spin_lock(&dev->req_lock);
1199 	}
1200 	spin_unlock(&dev->req_lock);
1201 	link->out_ep->desc = NULL;
1202 
1203 	/* finish forgetting about this USB link episode */
1204 	dev->header_len = 0;
1205 	dev->unwrap = NULL;
1206 	dev->wrap = NULL;
1207 
1208 	spin_lock(&dev->lock);
1209 	dev->port_usb = NULL;
1210 	spin_unlock(&dev->lock);
1211 }
1212 EXPORT_SYMBOL_GPL(gether_disconnect);
1213 
1214 MODULE_LICENSE("GPL");
1215 MODULE_AUTHOR("David Brownell");
1216