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