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#include <linux/string_helpers.h>
  21#include <linux/usb/composite.h>
  22
  23#include "u_ether.h"
  24
  25
  26/*
  27 * This component encapsulates the Ethernet link glue needed to provide
  28 * one (!) network link through the USB gadget stack, normally "usb0".
  29 *
  30 * The control and data models are handled by the function driver which
  31 * connects to this code; such as CDC Ethernet (ECM or EEM),
  32 * "CDC Subset", or RNDIS.  That includes all descriptor and endpoint
  33 * management.
  34 *
  35 * Link level addressing is handled by this component using module
  36 * parameters; if no such parameters are provided, random link level
  37 * addresses are used.  Each end of the link uses one address.  The
  38 * host end address is exported in various ways, and is often recorded
  39 * in configuration databases.
  40 *
  41 * The driver which assembles each configuration using such a link is
  42 * responsible for ensuring that each configuration includes at most one
  43 * instance of is network link.  (The network layer provides ways for
  44 * this single "physical" link to be used by multiple virtual links.)
  45 */
  46
  47#define UETH__VERSION	"29-May-2008"
  48
  49/* Experiments show that both Linux and Windows hosts allow up to 16k
  50 * frame sizes. Set the max MTU size to 15k+52 to prevent allocating 32k
  51 * blocks and still have efficient handling. */
  52#define GETHER_MAX_MTU_SIZE 15412
  53#define GETHER_MAX_ETH_FRAME_LEN (GETHER_MAX_MTU_SIZE + ETH_HLEN)
  54
  55struct eth_dev {
  56	/* lock is held while accessing port_usb
  57	 */
  58	spinlock_t		lock;
  59	struct gether		*port_usb;
  60
  61	struct net_device	*net;
  62	struct usb_gadget	*gadget;
  63
  64	spinlock_t		req_lock;	/* guard {rx,tx}_reqs */
  65	struct list_head	tx_reqs, rx_reqs;
  66	atomic_t		tx_qlen;
  67
  68	struct sk_buff_head	rx_frames;
  69
  70	unsigned		qmult;
  71
  72	unsigned		header_len;
  73	struct sk_buff		*(*wrap)(struct gether *, struct sk_buff *skb);
  74	int			(*unwrap)(struct gether *,
  75						struct sk_buff *skb,
  76						struct sk_buff_head *list);
  77
  78	struct work_struct	work;
  79
  80	unsigned long		todo;
  81#define	WORK_RX_MEMORY		0
  82
  83	bool			zlp;
  84	bool			no_skb_reserve;
  85	bool			ifname_set;
  86	u8			host_mac[ETH_ALEN];
  87	u8			dev_mac[ETH_ALEN];
  88};
  89
  90/*-------------------------------------------------------------------------*/
  91
  92#define RX_EXTRA	20	/* bytes guarding against rx overflows */
  93
  94#define DEFAULT_QLEN	2	/* double buffering by default */
  95
  96/* use deeper queues at high/super speed */
  97static inline int qlen(struct usb_gadget *gadget, unsigned qmult)
  98{
  99	if (gadget->speed == USB_SPEED_HIGH || gadget->speed >= USB_SPEED_SUPER)
 100		return qmult * DEFAULT_QLEN;
 101	else
 102		return DEFAULT_QLEN;
 103}
 104
 105/*-------------------------------------------------------------------------*/
 106
 107/* NETWORK DRIVER HOOKUP (to the layer above this driver) */
 108
 109static void eth_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *p)
 110{
 111	struct eth_dev *dev = netdev_priv(net);
 112
 113	strscpy(p->driver, "g_ether", sizeof(p->driver));
 114	strscpy(p->version, UETH__VERSION, sizeof(p->version));
 115	strscpy(p->fw_version, dev->gadget->name, sizeof(p->fw_version));
 116	strscpy(p->bus_info, dev_name(&dev->gadget->dev), sizeof(p->bus_info));
 117}
 118
 119/* REVISIT can also support:
 120 *   - WOL (by tracking suspends and issuing remote wakeup)
 121 *   - msglevel (implies updated messaging)
 122 *   - ... probably more ethtool ops
 123 */
 124
 125static const struct ethtool_ops ops = {
 126	.get_drvinfo = eth_get_drvinfo,
 127	.get_link = ethtool_op_get_link,
 128};
 129
 130static void defer_kevent(struct eth_dev *dev, int flag)
 131{
 132	if (test_and_set_bit(flag, &dev->todo))
 133		return;
 134	if (!schedule_work(&dev->work))
 135		ERROR(dev, "kevent %d may have been dropped\n", flag);
 136	else
 137		DBG(dev, "kevent %d scheduled\n", flag);
 138}
 139
 140static void rx_complete(struct usb_ep *ep, struct usb_request *req);
 141
 142static int
 143rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
 144{
 145	struct usb_gadget *g = dev->gadget;
 146	struct sk_buff	*skb;
 147	int		retval = -ENOMEM;
 148	size_t		size = 0;
 149	struct usb_ep	*out;
 150	unsigned long	flags;
 151
 152	spin_lock_irqsave(&dev->lock, flags);
 153	if (dev->port_usb)
 154		out = dev->port_usb->out_ep;
 155	else
 156		out = NULL;
 157
 158	if (!out)
 159	{
 160		spin_unlock_irqrestore(&dev->lock, flags);
 161		return -ENOTCONN;
 162	}
 163
 164	/* Padding up to RX_EXTRA handles minor disagreements with host.
 165	 * Normally we use the USB "terminate on short read" convention;
 166	 * so allow up to (N*maxpacket), since that memory is normally
 167	 * already allocated.  Some hardware doesn't deal well with short
 168	 * reads (e.g. DMA must be N*maxpacket), so for now don't trim a
 169	 * byte off the end (to force hardware errors on overflow).
 170	 *
 171	 * RNDIS uses internal framing, and explicitly allows senders to
 172	 * pad to end-of-packet.  That's potentially nice for speed, but
 173	 * means receivers can't recover lost synch on their own (because
 174	 * new packets don't only start after a short RX).
 175	 */
 176	size += sizeof(struct ethhdr) + dev->net->mtu + RX_EXTRA;
 177	size += dev->port_usb->header_len;
 178
 179	if (g->quirk_ep_out_aligned_size) {
 180		size += out->maxpacket - 1;
 181		size -= size % out->maxpacket;
 182	}
 183
 184	if (dev->port_usb->is_fixed)
 185		size = max_t(size_t, size, dev->port_usb->fixed_out_len);
 186	spin_unlock_irqrestore(&dev->lock, flags);
 187
 188	skb = __netdev_alloc_skb(dev->net, size + NET_IP_ALIGN, gfp_flags);
 189	if (skb == NULL) {
 190		DBG(dev, "no rx skb\n");
 191		goto enomem;
 192	}
 193
 194	/* Some platforms perform better when IP packets are aligned,
 195	 * but on at least one, checksumming fails otherwise.  Note:
 196	 * RNDIS headers involve variable numbers of LE32 values.
 197	 */
 198	if (likely(!dev->no_skb_reserve))
 199		skb_reserve(skb, NET_IP_ALIGN);
 200
 201	req->buf = skb->data;
 202	req->length = size;
 203	req->complete = rx_complete;
 204	req->context = skb;
 205
 206	retval = usb_ep_queue(out, req, gfp_flags);
 207	if (retval == -ENOMEM)
 208enomem:
 209		defer_kevent(dev, WORK_RX_MEMORY);
 210	if (retval) {
 211		DBG(dev, "rx submit --> %d\n", retval);
 212		if (skb)
 213			dev_kfree_skb_any(skb);
 214		spin_lock_irqsave(&dev->req_lock, flags);
 215		list_add(&req->list, &dev->rx_reqs);
 216		spin_unlock_irqrestore(&dev->req_lock, flags);
 217	}
 218	return retval;
 219}
 220
 221static void rx_complete(struct usb_ep *ep, struct usb_request *req)
 222{
 223	struct sk_buff	*skb = req->context, *skb2;
 224	struct eth_dev	*dev = ep->driver_data;
 225	int		status = req->status;
 226
 227	switch (status) {
 228
 229	/* normal completion */
 230	case 0:
 231		skb_put(skb, req->actual);
 232
 233		if (dev->unwrap) {
 234			unsigned long	flags;
 235
 236			spin_lock_irqsave(&dev->lock, flags);
 237			if (dev->port_usb) {
 238				status = dev->unwrap(dev->port_usb,
 239							skb,
 240							&dev->rx_frames);
 241			} else {
 242				dev_kfree_skb_any(skb);
 243				status = -ENOTCONN;
 244			}
 245			spin_unlock_irqrestore(&dev->lock, flags);
 246		} else {
 247			skb_queue_tail(&dev->rx_frames, skb);
 248		}
 249		skb = NULL;
 250
 251		skb2 = skb_dequeue(&dev->rx_frames);
 252		while (skb2) {
 253			if (status < 0
 254					|| ETH_HLEN > skb2->len
 255					|| skb2->len > GETHER_MAX_ETH_FRAME_LEN) {
 256				dev->net->stats.rx_errors++;
 257				dev->net->stats.rx_length_errors++;
 258				DBG(dev, "rx length %d\n", skb2->len);
 259				dev_kfree_skb_any(skb2);
 260				goto next_frame;
 261			}
 262			skb2->protocol = eth_type_trans(skb2, dev->net);
 263			dev->net->stats.rx_packets++;
 264			dev->net->stats.rx_bytes += skb2->len;
 265
 266			/* no buffer copies needed, unless hardware can't
 267			 * use skb buffers.
 268			 */
 269			status = netif_rx(skb2);
 270next_frame:
 271			skb2 = skb_dequeue(&dev->rx_frames);
 272		}
 273		break;
 274
 275	/* software-driven interface shutdown */
 276	case -ECONNRESET:		/* unlink */
 277	case -ESHUTDOWN:		/* disconnect etc */
 278		VDBG(dev, "rx shutdown, code %d\n", status);
 279		goto quiesce;
 280
 281	/* for hardware automagic (such as pxa) */
 282	case -ECONNABORTED:		/* endpoint reset */
 283		DBG(dev, "rx %s reset\n", ep->name);
 284		defer_kevent(dev, WORK_RX_MEMORY);
 285quiesce:
 286		dev_kfree_skb_any(skb);
 287		goto clean;
 288
 289	/* data overrun */
 290	case -EOVERFLOW:
 291		dev->net->stats.rx_over_errors++;
 292		fallthrough;
 293
 294	default:
 295		dev->net->stats.rx_errors++;
 296		DBG(dev, "rx status %d\n", status);
 297		break;
 298	}
 299
 300	if (skb)
 301		dev_kfree_skb_any(skb);
 302	if (!netif_running(dev->net)) {
 303clean:
 304		spin_lock(&dev->req_lock);
 305		list_add(&req->list, &dev->rx_reqs);
 306		spin_unlock(&dev->req_lock);
 307		req = NULL;
 308	}
 309	if (req)
 310		rx_submit(dev, req, GFP_ATOMIC);
 311}
 312
 313static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
 314{
 315	unsigned		i;
 316	struct usb_request	*req;
 317
 318	if (!n)
 319		return -ENOMEM;
 320
 321	/* queue/recycle up to N requests */
 322	i = n;
 323	list_for_each_entry(req, list, list) {
 324		if (i-- == 0)
 325			goto extra;
 326	}
 327	while (i--) {
 328		req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 329		if (!req)
 330			return list_empty(list) ? -ENOMEM : 0;
 331		list_add(&req->list, list);
 332	}
 333	return 0;
 334
 335extra:
 336	/* free extras */
 337	for (;;) {
 338		struct list_head	*next;
 339
 340		next = req->list.next;
 341		list_del(&req->list);
 342		usb_ep_free_request(ep, req);
 343
 344		if (next == list)
 345			break;
 346
 347		req = container_of(next, struct usb_request, list);
 348	}
 349	return 0;
 350}
 351
 352static int alloc_requests(struct eth_dev *dev, struct gether *link, unsigned n)
 353{
 354	int	status;
 355
 356	spin_lock(&dev->req_lock);
 357	status = prealloc(&dev->tx_reqs, link->in_ep, n);
 358	if (status < 0)
 359		goto fail;
 360	status = prealloc(&dev->rx_reqs, link->out_ep, n);
 361	if (status < 0)
 362		goto fail;
 363	goto done;
 364fail:
 365	DBG(dev, "can't alloc requests\n");
 366done:
 367	spin_unlock(&dev->req_lock);
 368	return status;
 369}
 370
 371static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
 372{
 373	struct usb_request	*req;
 374	unsigned long		flags;
 375
 376	/* fill unused rxq slots with some skb */
 377	spin_lock_irqsave(&dev->req_lock, flags);
 378	while (!list_empty(&dev->rx_reqs)) {
 379		req = list_first_entry(&dev->rx_reqs, struct usb_request, list);
 380		list_del_init(&req->list);
 381		spin_unlock_irqrestore(&dev->req_lock, flags);
 382
 383		if (rx_submit(dev, req, gfp_flags) < 0) {
 384			defer_kevent(dev, WORK_RX_MEMORY);
 385			return;
 386		}
 387
 388		spin_lock_irqsave(&dev->req_lock, flags);
 389	}
 390	spin_unlock_irqrestore(&dev->req_lock, flags);
 391}
 392
 393static void eth_work(struct work_struct *work)
 394{
 395	struct eth_dev	*dev = container_of(work, struct eth_dev, work);
 396
 397	if (test_and_clear_bit(WORK_RX_MEMORY, &dev->todo)) {
 398		if (netif_running(dev->net))
 399			rx_fill(dev, GFP_KERNEL);
 400	}
 401
 402	if (dev->todo)
 403		DBG(dev, "work done, flags = 0x%lx\n", dev->todo);
 404}
 405
 406static void tx_complete(struct usb_ep *ep, struct usb_request *req)
 407{
 408	struct sk_buff	*skb = req->context;
 409	struct eth_dev	*dev = ep->driver_data;
 410
 411	switch (req->status) {
 412	default:
 413		dev->net->stats.tx_errors++;
 414		VDBG(dev, "tx err %d\n", req->status);
 415		fallthrough;
 416	case -ECONNRESET:		/* unlink */
 417	case -ESHUTDOWN:		/* disconnect etc */
 418		dev_kfree_skb_any(skb);
 419		break;
 420	case 0:
 421		dev->net->stats.tx_bytes += skb->len;
 422		dev_consume_skb_any(skb);
 423	}
 424	dev->net->stats.tx_packets++;
 425
 426	spin_lock(&dev->req_lock);
 427	list_add(&req->list, &dev->tx_reqs);
 428	spin_unlock(&dev->req_lock);
 429
 430	atomic_dec(&dev->tx_qlen);
 431	if (netif_carrier_ok(dev->net))
 432		netif_wake_queue(dev->net);
 433}
 434
 435static inline int is_promisc(u16 cdc_filter)
 436{
 437	return cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
 438}
 439
 440static int ether_wakeup_host(struct gether *port)
 441{
 442	int			ret;
 443	struct usb_function	*func = &port->func;
 444	struct usb_gadget	*gadget = func->config->cdev->gadget;
 445
 446	if (func->func_suspended)
 447		ret = usb_func_wakeup(func);
 448	else
 449		ret = usb_gadget_wakeup(gadget);
 450
 451	return ret;
 452}
 453
 454static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
 455					struct net_device *net)
 456{
 457	struct eth_dev		*dev = netdev_priv(net);
 458	int			length = 0;
 459	int			retval;
 460	struct usb_request	*req = NULL;
 461	unsigned long		flags;
 462	struct usb_ep		*in;
 463	u16			cdc_filter;
 464
 465	spin_lock_irqsave(&dev->lock, flags);
 466	if (dev->port_usb) {
 467		in = dev->port_usb->in_ep;
 468		cdc_filter = dev->port_usb->cdc_filter;
 469	} else {
 470		in = NULL;
 471		cdc_filter = 0;
 472	}
 473
 474	if (dev->port_usb && dev->port_usb->is_suspend) {
 475		DBG(dev, "Port suspended. Triggering wakeup\n");
 476		netif_stop_queue(net);
 477		spin_unlock_irqrestore(&dev->lock, flags);
 478		ether_wakeup_host(dev->port_usb);
 479		return NETDEV_TX_BUSY;
 480	}
 481
 482	spin_unlock_irqrestore(&dev->lock, flags);
 483
 484	if (!in) {
 485		if (skb)
 486			dev_kfree_skb_any(skb);
 487		return NETDEV_TX_OK;
 488	}
 489
 490	/* apply outgoing CDC or RNDIS filters */
 491	if (skb && !is_promisc(cdc_filter)) {
 492		u8		*dest = skb->data;
 493
 494		if (is_multicast_ether_addr(dest)) {
 495			u16	type;
 496
 497			/* ignores USB_CDC_PACKET_TYPE_MULTICAST and host
 498			 * SET_ETHERNET_MULTICAST_FILTERS requests
 499			 */
 500			if (is_broadcast_ether_addr(dest))
 501				type = USB_CDC_PACKET_TYPE_BROADCAST;
 502			else
 503				type = USB_CDC_PACKET_TYPE_ALL_MULTICAST;
 504			if (!(cdc_filter & type)) {
 505				dev_kfree_skb_any(skb);
 506				return NETDEV_TX_OK;
 507			}
 508		}
 509		/* ignores USB_CDC_PACKET_TYPE_DIRECTED */
 510	}
 511
 512	spin_lock_irqsave(&dev->req_lock, flags);
 513	/*
 514	 * this freelist can be empty if an interrupt triggered disconnect()
 515	 * and reconfigured the gadget (shutting down this queue) after the
 516	 * network stack decided to xmit but before we got the spinlock.
 517	 */
 518	if (list_empty(&dev->tx_reqs)) {
 519		spin_unlock_irqrestore(&dev->req_lock, flags);
 520		return NETDEV_TX_BUSY;
 521	}
 522
 523	req = list_first_entry(&dev->tx_reqs, struct usb_request, list);
 524	list_del(&req->list);
 525
 526	/* temporarily stop TX queue when the freelist empties */
 527	if (list_empty(&dev->tx_reqs))
 528		netif_stop_queue(net);
 529	spin_unlock_irqrestore(&dev->req_lock, flags);
 530
 531	/* no buffer copies needed, unless the network stack did it
 532	 * or the hardware can't use skb buffers.
 533	 * or there's not enough space for extra headers we need
 534	 */
 535	if (dev->wrap) {
 536		unsigned long	flags;
 537
 538		spin_lock_irqsave(&dev->lock, flags);
 539		if (dev->port_usb)
 540			skb = dev->wrap(dev->port_usb, skb);
 541		spin_unlock_irqrestore(&dev->lock, flags);
 542		if (!skb) {
 543			/* Multi frame CDC protocols may store the frame for
 544			 * later which is not a dropped frame.
 545			 */
 546			if (dev->port_usb &&
 547					dev->port_usb->supports_multi_frame)
 548				goto multiframe;
 549			goto drop;
 550		}
 551	}
 552
 553	length = skb->len;
 554	req->buf = skb->data;
 555	req->context = skb;
 556	req->complete = tx_complete;
 557
 558	/* NCM requires no zlp if transfer is dwNtbInMaxSize */
 559	if (dev->port_usb &&
 560	    dev->port_usb->is_fixed &&
 561	    length == dev->port_usb->fixed_in_len &&
 562	    (length % in->maxpacket) == 0)
 563		req->zero = 0;
 564	else
 565		req->zero = 1;
 566
 567	/* use zlp framing on tx for strict CDC-Ether conformance,
 568	 * though any robust network rx path ignores extra padding.
 569	 * and some hardware doesn't like to write zlps.
 570	 */
 571	if (req->zero && !dev->zlp && (length % in->maxpacket) == 0)
 572		length++;
 573
 574	req->length = length;
 575
 576	retval = usb_ep_queue(in, req, GFP_ATOMIC);
 577	switch (retval) {
 578	default:
 579		DBG(dev, "tx queue err %d\n", retval);
 580		break;
 581	case 0:
 582		netif_trans_update(net);
 583		atomic_inc(&dev->tx_qlen);
 584	}
 585
 586	if (retval) {
 587		dev_kfree_skb_any(skb);
 588drop:
 589		dev->net->stats.tx_dropped++;
 590multiframe:
 591		spin_lock_irqsave(&dev->req_lock, flags);
 592		if (list_empty(&dev->tx_reqs))
 593			netif_start_queue(net);
 594		list_add(&req->list, &dev->tx_reqs);
 595		spin_unlock_irqrestore(&dev->req_lock, flags);
 596	}
 597	return NETDEV_TX_OK;
 598}
 599
 600/*-------------------------------------------------------------------------*/
 601
 602static void eth_start(struct eth_dev *dev, gfp_t gfp_flags)
 603{
 604	DBG(dev, "%s\n", __func__);
 605
 606	/* fill the rx queue */
 607	rx_fill(dev, gfp_flags);
 608
 609	/* and open the tx floodgates */
 610	atomic_set(&dev->tx_qlen, 0);
 611	netif_wake_queue(dev->net);
 612}
 613
 614static int eth_open(struct net_device *net)
 615{
 616	struct eth_dev	*dev = netdev_priv(net);
 617	struct gether	*link;
 618
 619	DBG(dev, "%s\n", __func__);
 620	if (netif_carrier_ok(dev->net))
 621		eth_start(dev, GFP_KERNEL);
 622
 623	spin_lock_irq(&dev->lock);
 624	link = dev->port_usb;
 625	if (link && link->open)
 626		link->open(link);
 627	spin_unlock_irq(&dev->lock);
 628
 629	return 0;
 630}
 631
 632static int eth_stop(struct net_device *net)
 633{
 634	struct eth_dev	*dev = netdev_priv(net);
 635	unsigned long	flags;
 636
 637	VDBG(dev, "%s\n", __func__);
 638	netif_stop_queue(net);
 639
 640	DBG(dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
 641		dev->net->stats.rx_packets, dev->net->stats.tx_packets,
 642		dev->net->stats.rx_errors, dev->net->stats.tx_errors
 643		);
 644
 645	/* ensure there are no more active requests */
 646	spin_lock_irqsave(&dev->lock, flags);
 647	if (dev->port_usb) {
 648		struct gether	*link = dev->port_usb;
 649		const struct usb_endpoint_descriptor *in;
 650		const struct usb_endpoint_descriptor *out;
 651
 652		if (link->close)
 653			link->close(link);
 654
 655		/* NOTE:  we have no abort-queue primitive we could use
 656		 * to cancel all pending I/O.  Instead, we disable then
 657		 * reenable the endpoints ... this idiom may leave toggle
 658		 * wrong, but that's a self-correcting error.
 659		 *
 660		 * REVISIT:  we *COULD* just let the transfers complete at
 661		 * their own pace; the network stack can handle old packets.
 662		 * For the moment we leave this here, since it works.
 663		 */
 664		in = link->in_ep->desc;
 665		out = link->out_ep->desc;
 666		usb_ep_disable(link->in_ep);
 667		usb_ep_disable(link->out_ep);
 668		if (netif_carrier_ok(net)) {
 669			DBG(dev, "host still using in/out endpoints\n");
 670			link->in_ep->desc = in;
 671			link->out_ep->desc = out;
 672			usb_ep_enable(link->in_ep);
 673			usb_ep_enable(link->out_ep);
 674		}
 675	}
 676	spin_unlock_irqrestore(&dev->lock, flags);
 677
 678	return 0;
 679}
 680
 681/*-------------------------------------------------------------------------*/
 682
 683static int get_ether_addr(const char *str, u8 *dev_addr)
 684{
 685	if (str) {
 686		unsigned	i;
 687
 688		for (i = 0; i < 6; i++) {
 689			unsigned char num;
 690
 691			if ((*str == '.') || (*str == ':'))
 692				str++;
 693			num = hex_to_bin(*str++) << 4;
 694			num |= hex_to_bin(*str++);
 695			dev_addr [i] = num;
 696		}
 697		if (is_valid_ether_addr(dev_addr))
 698			return 0;
 699	}
 700	eth_random_addr(dev_addr);
 701	return 1;
 702}
 703
 704static int get_ether_addr_str(u8 dev_addr[ETH_ALEN], char *str, int len)
 705{
 706	if (len < 18)
 707		return -EINVAL;
 708
 709	snprintf(str, len, "%pM", dev_addr);
 710	return 18;
 711}
 712
 713static const struct net_device_ops eth_netdev_ops = {
 714	.ndo_open		= eth_open,
 715	.ndo_stop		= eth_stop,
 716	.ndo_start_xmit		= eth_start_xmit,
 717	.ndo_set_mac_address 	= eth_mac_addr,
 718	.ndo_validate_addr	= eth_validate_addr,
 719};
 720
 721static struct device_type gadget_type = {
 722	.name	= "gadget",
 723};
 724
 725/*
 726 * gether_setup_name - initialize one ethernet-over-usb link
 727 * @g: gadget to associated with these links
 728 * @ethaddr: NULL, or a buffer in which the ethernet address of the
 729 *	host side of the link is recorded
 730 * @netname: name for network device (for example, "usb")
 731 * Context: may sleep
 732 *
 733 * This sets up the single network link that may be exported by a
 734 * gadget driver using this framework.  The link layer addresses are
 735 * set up using module parameters.
 736 *
 737 * Returns an eth_dev pointer on success, or an ERR_PTR on failure.
 738 */
 739struct eth_dev *gether_setup_name(struct usb_gadget *g,
 740		const char *dev_addr, const char *host_addr,
 741		u8 ethaddr[ETH_ALEN], unsigned qmult, const char *netname)
 742{
 743	struct eth_dev		*dev;
 744	struct net_device	*net;
 745	int			status;
 746	u8			addr[ETH_ALEN];
 747
 748	net = alloc_etherdev(sizeof *dev);
 749	if (!net)
 750		return ERR_PTR(-ENOMEM);
 751
 752	dev = netdev_priv(net);
 753	spin_lock_init(&dev->lock);
 754	spin_lock_init(&dev->req_lock);
 755	INIT_WORK(&dev->work, eth_work);
 756	INIT_LIST_HEAD(&dev->tx_reqs);
 757	INIT_LIST_HEAD(&dev->rx_reqs);
 758
 759	skb_queue_head_init(&dev->rx_frames);
 760
 761	/* network device setup */
 762	dev->net = net;
 763	dev->qmult = qmult;
 764	snprintf(net->name, sizeof(net->name), "%s%%d", netname);
 765
 766	if (get_ether_addr(dev_addr, addr)) {
 767		net->addr_assign_type = NET_ADDR_RANDOM;
 768		dev_warn(&g->dev,
 769			"using random %s ethernet address\n", "self");
 770	} else {
 771		net->addr_assign_type = NET_ADDR_SET;
 772	}
 773	eth_hw_addr_set(net, addr);
 774	if (get_ether_addr(host_addr, dev->host_mac))
 775		dev_warn(&g->dev,
 776			"using random %s ethernet address\n", "host");
 777
 778	if (ethaddr)
 779		memcpy(ethaddr, dev->host_mac, ETH_ALEN);
 780
 781	net->netdev_ops = &eth_netdev_ops;
 782
 783	net->ethtool_ops = &ops;
 784
 785	/* MTU range: 14 - 15412 */
 786	net->min_mtu = ETH_HLEN;
 787	net->max_mtu = GETHER_MAX_MTU_SIZE;
 788
 789	dev->gadget = g;
 790	SET_NETDEV_DEV(net, &g->dev);
 791	SET_NETDEV_DEVTYPE(net, &gadget_type);
 792
 793	status = register_netdev(net);
 794	if (status < 0) {
 795		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
 796		free_netdev(net);
 797		dev = ERR_PTR(status);
 798	} else {
 799		INFO(dev, "MAC %pM\n", net->dev_addr);
 800		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
 801
 802		/*
 803		 * two kinds of host-initiated state changes:
 804		 *  - iff DATA transfer is active, carrier is "on"
 805		 *  - tx queueing enabled if open *and* carrier is "on"
 806		 */
 807		netif_carrier_off(net);
 808	}
 809
 810	return dev;
 811}
 812EXPORT_SYMBOL_GPL(gether_setup_name);
 813
 814struct net_device *gether_setup_name_default(const char *netname)
 815{
 816	struct net_device	*net;
 817	struct eth_dev		*dev;
 818
 819	net = alloc_etherdev(sizeof(*dev));
 820	if (!net)
 821		return ERR_PTR(-ENOMEM);
 822
 823	dev = netdev_priv(net);
 824	spin_lock_init(&dev->lock);
 825	spin_lock_init(&dev->req_lock);
 826	INIT_WORK(&dev->work, eth_work);
 827	INIT_LIST_HEAD(&dev->tx_reqs);
 828	INIT_LIST_HEAD(&dev->rx_reqs);
 829
 830	skb_queue_head_init(&dev->rx_frames);
 831
 832	/* network device setup */
 833	dev->net = net;
 834	dev->qmult = QMULT_DEFAULT;
 835	snprintf(net->name, sizeof(net->name), "%s%%d", netname);
 836
 837	eth_random_addr(dev->dev_mac);
 838
 839	/* by default we always have a random MAC address */
 840	net->addr_assign_type = NET_ADDR_RANDOM;
 841
 842	eth_random_addr(dev->host_mac);
 843
 844	net->netdev_ops = &eth_netdev_ops;
 845
 846	net->ethtool_ops = &ops;
 847	SET_NETDEV_DEVTYPE(net, &gadget_type);
 848
 849	/* MTU range: 14 - 15412 */
 850	net->min_mtu = ETH_HLEN;
 851	net->max_mtu = GETHER_MAX_MTU_SIZE;
 852
 853	return net;
 854}
 855EXPORT_SYMBOL_GPL(gether_setup_name_default);
 856
 857int gether_register_netdev(struct net_device *net)
 858{
 859	struct eth_dev *dev;
 860	struct usb_gadget *g;
 861	int status;
 862
 863	if (!net->dev.parent)
 864		return -EINVAL;
 865	dev = netdev_priv(net);
 866	g = dev->gadget;
 867
 868	eth_hw_addr_set(net, dev->dev_mac);
 869
 870	status = register_netdev(net);
 871	if (status < 0) {
 872		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
 873		return status;
 874	} else {
 875		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
 876		INFO(dev, "MAC %pM\n", dev->dev_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
 885	return status;
 886}
 887EXPORT_SYMBOL_GPL(gether_register_netdev);
 888
 889void gether_set_gadget(struct net_device *net, struct usb_gadget *g)
 890{
 891	struct eth_dev *dev;
 892
 893	dev = netdev_priv(net);
 894	dev->gadget = g;
 895	SET_NETDEV_DEV(net, &g->dev);
 896}
 897EXPORT_SYMBOL_GPL(gether_set_gadget);
 898
 899int gether_set_dev_addr(struct net_device *net, const char *dev_addr)
 900{
 901	struct eth_dev *dev;
 902	u8 new_addr[ETH_ALEN];
 903
 904	dev = netdev_priv(net);
 905	if (get_ether_addr(dev_addr, new_addr))
 906		return -EINVAL;
 907	memcpy(dev->dev_mac, new_addr, ETH_ALEN);
 908	net->addr_assign_type = NET_ADDR_SET;
 909	return 0;
 910}
 911EXPORT_SYMBOL_GPL(gether_set_dev_addr);
 912
 913int gether_get_dev_addr(struct net_device *net, char *dev_addr, int len)
 914{
 915	struct eth_dev *dev;
 916	int ret;
 917
 918	dev = netdev_priv(net);
 919	ret = get_ether_addr_str(dev->dev_mac, dev_addr, len);
 920	if (ret + 1 < len) {
 921		dev_addr[ret++] = '\n';
 922		dev_addr[ret] = '\0';
 923	}
 924
 925	return ret;
 926}
 927EXPORT_SYMBOL_GPL(gether_get_dev_addr);
 928
 929int gether_set_host_addr(struct net_device *net, const char *host_addr)
 930{
 931	struct eth_dev *dev;
 932	u8 new_addr[ETH_ALEN];
 933
 934	dev = netdev_priv(net);
 935	if (get_ether_addr(host_addr, new_addr))
 936		return -EINVAL;
 937	memcpy(dev->host_mac, new_addr, ETH_ALEN);
 938	return 0;
 939}
 940EXPORT_SYMBOL_GPL(gether_set_host_addr);
 941
 942int gether_get_host_addr(struct net_device *net, char *host_addr, int len)
 943{
 944	struct eth_dev *dev;
 945	int ret;
 946
 947	dev = netdev_priv(net);
 948	ret = get_ether_addr_str(dev->host_mac, host_addr, len);
 949	if (ret + 1 < len) {
 950		host_addr[ret++] = '\n';
 951		host_addr[ret] = '\0';
 952	}
 953
 954	return ret;
 955}
 956EXPORT_SYMBOL_GPL(gether_get_host_addr);
 957
 958int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
 959{
 960	struct eth_dev *dev;
 961
 962	if (len < 13)
 963		return -EINVAL;
 964
 965	dev = netdev_priv(net);
 966	snprintf(host_addr, len, "%pm", dev->host_mac);
 967
 968	string_upper(host_addr, host_addr);
 969
 970	return strlen(host_addr);
 971}
 972EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
 973
 974void 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}
 981EXPORT_SYMBOL_GPL(gether_get_host_addr_u8);
 982
 983void 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}
 990EXPORT_SYMBOL_GPL(gether_set_qmult);
 991
 992unsigned gether_get_qmult(struct net_device *net)
 993{
 994	struct eth_dev *dev;
 995
 996	dev = netdev_priv(net);
 997	return dev->qmult;
 998}
 999EXPORT_SYMBOL_GPL(gether_get_qmult);
1000
1001int gether_get_ifname(struct net_device *net, char *name, int len)
1002{
1003	struct eth_dev *dev = netdev_priv(net);
1004	int ret;
1005
1006	rtnl_lock();
1007	ret = scnprintf(name, len, "%s\n",
1008			dev->ifname_set ? net->name : netdev_name(net));
1009	rtnl_unlock();
1010	return ret;
1011}
1012EXPORT_SYMBOL_GPL(gether_get_ifname);
1013
1014int gether_set_ifname(struct net_device *net, const char *name, int len)
1015{
1016	struct eth_dev *dev = netdev_priv(net);
1017	char tmp[IFNAMSIZ];
1018	const char *p;
1019
1020	if (name[len - 1] == '\n')
1021		len--;
1022
1023	if (len >= sizeof(tmp))
1024		return -E2BIG;
1025
1026	strscpy(tmp, name, len + 1);
1027	if (!dev_valid_name(tmp))
1028		return -EINVAL;
1029
1030	/* Require exactly one %d, so binding will not fail with EEXIST. */
1031	p = strchr(name, '%');
1032	if (!p || p[1] != 'd' || strchr(p + 2, '%'))
1033		return -EINVAL;
1034
1035	strncpy(net->name, tmp, sizeof(net->name));
1036	dev->ifname_set = true;
1037
1038	return 0;
1039}
1040EXPORT_SYMBOL_GPL(gether_set_ifname);
1041
1042void gether_suspend(struct gether *link)
1043{
1044	struct eth_dev *dev = link->ioport;
1045	unsigned long flags;
1046
1047	if (!dev)
1048		return;
1049
1050	if (atomic_read(&dev->tx_qlen)) {
1051		/*
1052		 * There is a transfer in progress. So we trigger a remote
1053		 * wakeup to inform the host.
1054		 */
1055		ether_wakeup_host(dev->port_usb);
1056		return;
1057	}
1058	spin_lock_irqsave(&dev->lock, flags);
1059	link->is_suspend = true;
1060	spin_unlock_irqrestore(&dev->lock, flags);
1061}
1062EXPORT_SYMBOL_GPL(gether_suspend);
1063
1064void gether_resume(struct gether *link)
1065{
1066	struct eth_dev *dev = link->ioport;
1067	unsigned long flags;
1068
1069	if (!dev)
1070		return;
1071
1072	if (netif_queue_stopped(dev->net))
1073		netif_start_queue(dev->net);
1074
1075	spin_lock_irqsave(&dev->lock, flags);
1076	link->is_suspend = false;
1077	spin_unlock_irqrestore(&dev->lock, flags);
1078}
1079EXPORT_SYMBOL_GPL(gether_resume);
1080
1081/*
1082 * gether_cleanup - remove Ethernet-over-USB device
1083 * Context: may sleep
1084 *
1085 * This is called to free all resources allocated by @gether_setup().
1086 */
1087void gether_cleanup(struct eth_dev *dev)
1088{
1089	if (!dev)
1090		return;
1091
1092	unregister_netdev(dev->net);
1093	flush_work(&dev->work);
1094	free_netdev(dev->net);
1095}
1096EXPORT_SYMBOL_GPL(gether_cleanup);
1097
1098/**
1099 * gether_connect - notify network layer that USB link is active
1100 * @link: the USB link, set up with endpoints, descriptors matching
1101 *	current device speed, and any framing wrapper(s) set up.
1102 * Context: irqs blocked
1103 *
1104 * This is called to activate endpoints and let the network layer know
1105 * the connection is active ("carrier detect").  It may cause the I/O
1106 * queues to open and start letting network packets flow, but will in
1107 * any case activate the endpoints so that they respond properly to the
1108 * USB host.
1109 *
1110 * Verify net_device pointer returned using IS_ERR().  If it doesn't
1111 * indicate some error code (negative errno), ep->driver_data values
1112 * have been overwritten.
1113 */
1114struct net_device *gether_connect(struct gether *link)
1115{
1116	struct eth_dev		*dev = link->ioport;
1117	int			result = 0;
1118
1119	if (!dev)
1120		return ERR_PTR(-EINVAL);
1121
1122	link->in_ep->driver_data = dev;
1123	result = usb_ep_enable(link->in_ep);
1124	if (result != 0) {
1125		DBG(dev, "enable %s --> %d\n",
1126			link->in_ep->name, result);
1127		goto fail0;
1128	}
1129
1130	link->out_ep->driver_data = dev;
1131	result = usb_ep_enable(link->out_ep);
1132	if (result != 0) {
1133		DBG(dev, "enable %s --> %d\n",
1134			link->out_ep->name, result);
1135		goto fail1;
1136	}
1137
1138	if (result == 0)
1139		result = alloc_requests(dev, link, qlen(dev->gadget,
1140					dev->qmult));
1141
1142	if (result == 0) {
1143		dev->zlp = link->is_zlp_ok;
1144		dev->no_skb_reserve = gadget_avoids_skb_reserve(dev->gadget);
1145		DBG(dev, "qlen %d\n", qlen(dev->gadget, dev->qmult));
1146
1147		dev->header_len = link->header_len;
1148		dev->unwrap = link->unwrap;
1149		dev->wrap = link->wrap;
1150
1151		spin_lock(&dev->lock);
1152		dev->port_usb = link;
1153		if (netif_running(dev->net)) {
1154			if (link->open)
1155				link->open(link);
1156		} else {
1157			if (link->close)
1158				link->close(link);
1159		}
1160		spin_unlock(&dev->lock);
1161
1162		netif_carrier_on(dev->net);
1163		if (netif_running(dev->net))
1164			eth_start(dev, GFP_ATOMIC);
1165
1166		netif_device_attach(dev->net);
1167
1168	/* on error, disable any endpoints  */
1169	} else {
1170		(void) usb_ep_disable(link->out_ep);
1171fail1:
1172		(void) usb_ep_disable(link->in_ep);
1173	}
1174fail0:
1175	/* caller is responsible for cleanup on error */
1176	if (result < 0)
1177		return ERR_PTR(result);
1178	return dev->net;
1179}
1180EXPORT_SYMBOL_GPL(gether_connect);
1181
1182/**
1183 * gether_disconnect - notify network layer that USB link is inactive
1184 * @link: the USB link, on which gether_connect() was called
1185 * Context: irqs blocked
1186 *
1187 * This is called to deactivate endpoints and let the network layer know
1188 * the connection went inactive ("no carrier").
1189 *
1190 * On return, the state is as if gether_connect() had never been called.
1191 * The endpoints are inactive, and accordingly without active USB I/O.
1192 * Pointers to endpoint descriptors and endpoint private data are nulled.
1193 */
1194void gether_disconnect(struct gether *link)
1195{
1196	struct eth_dev		*dev = link->ioport;
1197	struct usb_request	*req;
1198
1199	WARN_ON(!dev);
1200	if (!dev)
1201		return;
1202
1203	DBG(dev, "%s\n", __func__);
1204
1205	netif_device_detach(dev->net);
1206	netif_carrier_off(dev->net);
1207
1208	/* disable endpoints, forcing (synchronous) completion
1209	 * of all pending i/o.  then free the request objects
1210	 * and forget about the endpoints.
1211	 */
1212	usb_ep_disable(link->in_ep);
1213	spin_lock(&dev->req_lock);
1214	while (!list_empty(&dev->tx_reqs)) {
1215		req = list_first_entry(&dev->tx_reqs, struct usb_request, list);
1216		list_del(&req->list);
1217
1218		spin_unlock(&dev->req_lock);
1219		usb_ep_free_request(link->in_ep, req);
1220		spin_lock(&dev->req_lock);
1221	}
1222	spin_unlock(&dev->req_lock);
1223	link->in_ep->desc = NULL;
1224
1225	usb_ep_disable(link->out_ep);
1226	spin_lock(&dev->req_lock);
1227	while (!list_empty(&dev->rx_reqs)) {
1228		req = list_first_entry(&dev->rx_reqs, struct usb_request, list);
1229		list_del(&req->list);
1230
1231		spin_unlock(&dev->req_lock);
1232		usb_ep_free_request(link->out_ep, req);
1233		spin_lock(&dev->req_lock);
1234	}
1235	spin_unlock(&dev->req_lock);
1236	link->out_ep->desc = NULL;
1237
1238	/* finish forgetting about this USB link episode */
1239	dev->header_len = 0;
1240	dev->unwrap = NULL;
1241	dev->wrap = NULL;
1242
1243	spin_lock(&dev->lock);
1244	dev->port_usb = NULL;
1245	link->is_suspend = false;
1246	spin_unlock(&dev->lock);
1247}
1248EXPORT_SYMBOL_GPL(gether_disconnect);
1249
 
1250MODULE_LICENSE("GPL");
1251MODULE_AUTHOR("David Brownell");