cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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rndis_host.c (21014B)


      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Host Side support for RNDIS Networking Links
      4 * Copyright (C) 2005 by David Brownell
      5 */
      6#include <linux/module.h>
      7#include <linux/netdevice.h>
      8#include <linux/etherdevice.h>
      9#include <linux/ethtool.h>
     10#include <linux/workqueue.h>
     11#include <linux/slab.h>
     12#include <linux/mii.h>
     13#include <linux/usb.h>
     14#include <linux/usb/cdc.h>
     15#include <linux/usb/usbnet.h>
     16#include <linux/usb/rndis_host.h>
     17
     18
     19/*
     20 * RNDIS is NDIS remoted over USB.  It's a MSFT variant of CDC ACM ... of
     21 * course ACM was intended for modems, not Ethernet links!  USB's standard
     22 * for Ethernet links is "CDC Ethernet", which is significantly simpler.
     23 *
     24 * NOTE that Microsoft's "RNDIS 1.0" specification is incomplete.  Issues
     25 * include:
     26 *    - Power management in particular relies on information that's scattered
     27 *	through other documentation, and which is incomplete or incorrect even
     28 *	there.
     29 *    - There are various undocumented protocol requirements, such as the
     30 *	need to send unused garbage in control-OUT messages.
     31 *    - In some cases, MS-Windows will emit undocumented requests; this
     32 *	matters more to peripheral implementations than host ones.
     33 *
     34 * Moreover there's a no-open-specs variant of RNDIS called "ActiveSync".
     35 *
     36 * For these reasons and others, ** USE OF RNDIS IS STRONGLY DISCOURAGED ** in
     37 * favor of such non-proprietary alternatives as CDC Ethernet or the newer (and
     38 * currently rare) "Ethernet Emulation Model" (EEM).
     39 */
     40
     41/*
     42 * RNDIS notifications from device: command completion; "reverse"
     43 * keepalives; etc
     44 */
     45void rndis_status(struct usbnet *dev, struct urb *urb)
     46{
     47	netdev_dbg(dev->net, "rndis status urb, len %d stat %d\n",
     48		   urb->actual_length, urb->status);
     49	// FIXME for keepalives, respond immediately (asynchronously)
     50	// if not an RNDIS status, do like cdc_status(dev,urb) does
     51}
     52EXPORT_SYMBOL_GPL(rndis_status);
     53
     54/*
     55 * RNDIS indicate messages.
     56 */
     57static void rndis_msg_indicate(struct usbnet *dev, struct rndis_indicate *msg,
     58				int buflen)
     59{
     60	struct cdc_state *info = (void *)&dev->data;
     61	struct device *udev = &info->control->dev;
     62
     63	if (dev->driver_info->indication) {
     64		dev->driver_info->indication(dev, msg, buflen);
     65	} else {
     66		u32 status = le32_to_cpu(msg->status);
     67
     68		switch (status) {
     69		case RNDIS_STATUS_MEDIA_CONNECT:
     70			dev_info(udev, "rndis media connect\n");
     71			break;
     72		case RNDIS_STATUS_MEDIA_DISCONNECT:
     73			dev_info(udev, "rndis media disconnect\n");
     74			break;
     75		default:
     76			dev_info(udev, "rndis indication: 0x%08x\n", status);
     77		}
     78	}
     79}
     80
     81/*
     82 * RPC done RNDIS-style.  Caller guarantees:
     83 * - message is properly byteswapped
     84 * - there's no other request pending
     85 * - buf can hold up to 1KB response (required by RNDIS spec)
     86 * On return, the first few entries are already byteswapped.
     87 *
     88 * Call context is likely probe(), before interface name is known,
     89 * which is why we won't try to use it in the diagnostics.
     90 */
     91int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
     92{
     93	struct cdc_state	*info = (void *) &dev->data;
     94	struct usb_cdc_notification notification;
     95	int			master_ifnum;
     96	int			retval;
     97	int			partial;
     98	unsigned		count;
     99	u32			xid = 0, msg_len, request_id, msg_type, rsp,
    100				status;
    101
    102	/* REVISIT when this gets called from contexts other than probe() or
    103	 * disconnect(): either serialize, or dispatch responses on xid
    104	 */
    105
    106	msg_type = le32_to_cpu(buf->msg_type);
    107
    108	/* Issue the request; xid is unique, don't bother byteswapping it */
    109	if (likely(msg_type != RNDIS_MSG_HALT && msg_type != RNDIS_MSG_RESET)) {
    110		xid = dev->xid++;
    111		if (!xid)
    112			xid = dev->xid++;
    113		buf->request_id = (__force __le32) xid;
    114	}
    115	master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
    116	retval = usb_control_msg(dev->udev,
    117		usb_sndctrlpipe(dev->udev, 0),
    118		USB_CDC_SEND_ENCAPSULATED_COMMAND,
    119		USB_TYPE_CLASS | USB_RECIP_INTERFACE,
    120		0, master_ifnum,
    121		buf, le32_to_cpu(buf->msg_len),
    122		RNDIS_CONTROL_TIMEOUT_MS);
    123	if (unlikely(retval < 0 || xid == 0))
    124		return retval;
    125
    126	/* Some devices don't respond on the control channel until
    127	 * polled on the status channel, so do that first. */
    128	if (dev->driver_info->data & RNDIS_DRIVER_DATA_POLL_STATUS) {
    129		retval = usb_interrupt_msg(
    130			dev->udev,
    131			usb_rcvintpipe(dev->udev,
    132				       dev->status->desc.bEndpointAddress),
    133			&notification, sizeof(notification), &partial,
    134			RNDIS_CONTROL_TIMEOUT_MS);
    135		if (unlikely(retval < 0))
    136			return retval;
    137	}
    138
    139	/* Poll the control channel; the request probably completed immediately */
    140	rsp = le32_to_cpu(buf->msg_type) | RNDIS_MSG_COMPLETION;
    141	for (count = 0; count < 10; count++) {
    142		memset(buf, 0, CONTROL_BUFFER_SIZE);
    143		retval = usb_control_msg(dev->udev,
    144			usb_rcvctrlpipe(dev->udev, 0),
    145			USB_CDC_GET_ENCAPSULATED_RESPONSE,
    146			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
    147			0, master_ifnum,
    148			buf, buflen,
    149			RNDIS_CONTROL_TIMEOUT_MS);
    150		if (likely(retval >= 8)) {
    151			msg_type = le32_to_cpu(buf->msg_type);
    152			msg_len = le32_to_cpu(buf->msg_len);
    153			status = le32_to_cpu(buf->status);
    154			request_id = (__force u32) buf->request_id;
    155			if (likely(msg_type == rsp)) {
    156				if (likely(request_id == xid)) {
    157					if (unlikely(rsp == RNDIS_MSG_RESET_C))
    158						return 0;
    159					if (likely(RNDIS_STATUS_SUCCESS ==
    160							status))
    161						return 0;
    162					dev_dbg(&info->control->dev,
    163						"rndis reply status %08x\n",
    164						status);
    165					return -EL3RST;
    166				}
    167				dev_dbg(&info->control->dev,
    168					"rndis reply id %d expected %d\n",
    169					request_id, xid);
    170				/* then likely retry */
    171			} else switch (msg_type) {
    172			case RNDIS_MSG_INDICATE: /* fault/event */
    173				rndis_msg_indicate(dev, (void *)buf, buflen);
    174				break;
    175			case RNDIS_MSG_KEEPALIVE: { /* ping */
    176				struct rndis_keepalive_c *msg = (void *)buf;
    177
    178				msg->msg_type = cpu_to_le32(RNDIS_MSG_KEEPALIVE_C);
    179				msg->msg_len = cpu_to_le32(sizeof *msg);
    180				msg->status = cpu_to_le32(RNDIS_STATUS_SUCCESS);
    181				retval = usb_control_msg(dev->udev,
    182					usb_sndctrlpipe(dev->udev, 0),
    183					USB_CDC_SEND_ENCAPSULATED_COMMAND,
    184					USB_TYPE_CLASS | USB_RECIP_INTERFACE,
    185					0, master_ifnum,
    186					msg, sizeof *msg,
    187					RNDIS_CONTROL_TIMEOUT_MS);
    188				if (unlikely(retval < 0))
    189					dev_dbg(&info->control->dev,
    190						"rndis keepalive err %d\n",
    191						retval);
    192				}
    193				break;
    194			default:
    195				dev_dbg(&info->control->dev,
    196					"unexpected rndis msg %08x len %d\n",
    197					le32_to_cpu(buf->msg_type), msg_len);
    198			}
    199		} else {
    200			/* device probably issued a protocol stall; ignore */
    201			dev_dbg(&info->control->dev,
    202				"rndis response error, code %d\n", retval);
    203		}
    204		msleep(40);
    205	}
    206	dev_dbg(&info->control->dev, "rndis response timeout\n");
    207	return -ETIMEDOUT;
    208}
    209EXPORT_SYMBOL_GPL(rndis_command);
    210
    211/*
    212 * rndis_query:
    213 *
    214 * Performs a query for @oid along with 0 or more bytes of payload as
    215 * specified by @in_len. If @reply_len is not set to -1 then the reply
    216 * length is checked against this value, resulting in an error if it
    217 * doesn't match.
    218 *
    219 * NOTE: Adding a payload exactly or greater than the size of the expected
    220 * response payload is an evident requirement MSFT added for ActiveSync.
    221 *
    222 * The only exception is for OIDs that return a variably sized response,
    223 * in which case no payload should be added.  This undocumented (and
    224 * nonsensical!) issue was found by sniffing protocol requests from the
    225 * ActiveSync 4.1 Windows driver.
    226 */
    227static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
    228		void *buf, u32 oid, u32 in_len,
    229		void **reply, int *reply_len)
    230{
    231	int retval;
    232	union {
    233		void			*buf;
    234		struct rndis_msg_hdr	*header;
    235		struct rndis_query	*get;
    236		struct rndis_query_c	*get_c;
    237	} u;
    238	u32 off, len;
    239
    240	u.buf = buf;
    241
    242	memset(u.get, 0, sizeof *u.get + in_len);
    243	u.get->msg_type = cpu_to_le32(RNDIS_MSG_QUERY);
    244	u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
    245	u.get->oid = cpu_to_le32(oid);
    246	u.get->len = cpu_to_le32(in_len);
    247	u.get->offset = cpu_to_le32(20);
    248
    249	retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
    250	if (unlikely(retval < 0)) {
    251		dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
    252				oid, retval);
    253		return retval;
    254	}
    255
    256	off = le32_to_cpu(u.get_c->offset);
    257	len = le32_to_cpu(u.get_c->len);
    258	if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
    259		goto response_error;
    260
    261	if (*reply_len != -1 && len != *reply_len)
    262		goto response_error;
    263
    264	*reply = (unsigned char *) &u.get_c->request_id + off;
    265	*reply_len = len;
    266
    267	return retval;
    268
    269response_error:
    270	dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
    271			"invalid response - off %d len %d\n",
    272		oid, off, len);
    273	return -EDOM;
    274}
    275
    276/* same as usbnet_netdev_ops but MTU change not allowed */
    277static const struct net_device_ops rndis_netdev_ops = {
    278	.ndo_open		= usbnet_open,
    279	.ndo_stop		= usbnet_stop,
    280	.ndo_start_xmit		= usbnet_start_xmit,
    281	.ndo_tx_timeout		= usbnet_tx_timeout,
    282	.ndo_get_stats64	= dev_get_tstats64,
    283	.ndo_set_mac_address 	= eth_mac_addr,
    284	.ndo_validate_addr	= eth_validate_addr,
    285};
    286
    287int
    288generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags)
    289{
    290	int			retval;
    291	struct net_device	*net = dev->net;
    292	struct cdc_state	*info = (void *) &dev->data;
    293	union {
    294		void			*buf;
    295		struct rndis_msg_hdr	*header;
    296		struct rndis_init	*init;
    297		struct rndis_init_c	*init_c;
    298		struct rndis_query	*get;
    299		struct rndis_query_c	*get_c;
    300		struct rndis_set	*set;
    301		struct rndis_set_c	*set_c;
    302		struct rndis_halt	*halt;
    303	} u;
    304	u32			tmp;
    305	__le32			phym_unspec, *phym;
    306	int			reply_len;
    307	unsigned char		*bp;
    308
    309	/* we can't rely on i/o from stack working, or stack allocation */
    310	u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
    311	if (!u.buf)
    312		return -ENOMEM;
    313	retval = usbnet_generic_cdc_bind(dev, intf);
    314	if (retval < 0)
    315		goto fail;
    316
    317	u.init->msg_type = cpu_to_le32(RNDIS_MSG_INIT);
    318	u.init->msg_len = cpu_to_le32(sizeof *u.init);
    319	u.init->major_version = cpu_to_le32(1);
    320	u.init->minor_version = cpu_to_le32(0);
    321
    322	/* max transfer (in spec) is 0x4000 at full speed, but for
    323	 * TX we'll stick to one Ethernet packet plus RNDIS framing.
    324	 * For RX we handle drivers that zero-pad to end-of-packet.
    325	 * Don't let userspace change these settings.
    326	 *
    327	 * NOTE: there still seems to be weirdness here, as if we need
    328	 * to do some more things to make sure WinCE targets accept this.
    329	 * They default to jumbograms of 8KB or 16KB, which is absurd
    330	 * for such low data rates and which is also more than Linux
    331	 * can usually expect to allocate for SKB data...
    332	 */
    333	net->hard_header_len += sizeof (struct rndis_data_hdr);
    334	dev->hard_mtu = net->mtu + net->hard_header_len;
    335
    336	dev->maxpacket = usb_maxpacket(dev->udev, dev->out);
    337	if (dev->maxpacket == 0) {
    338		netif_dbg(dev, probe, dev->net,
    339			  "dev->maxpacket can't be 0\n");
    340		retval = -EINVAL;
    341		goto fail_and_release;
    342	}
    343
    344	dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
    345	dev->rx_urb_size &= ~(dev->maxpacket - 1);
    346	u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
    347
    348	net->netdev_ops = &rndis_netdev_ops;
    349
    350	retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
    351	if (unlikely(retval < 0)) {
    352		/* it might not even be an RNDIS device!! */
    353		dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
    354		goto fail_and_release;
    355	}
    356	tmp = le32_to_cpu(u.init_c->max_transfer_size);
    357	if (tmp < dev->hard_mtu) {
    358		if (tmp <= net->hard_header_len) {
    359			dev_err(&intf->dev,
    360				"dev can't take %u byte packets (max %u)\n",
    361				dev->hard_mtu, tmp);
    362			retval = -EINVAL;
    363			goto halt_fail_and_release;
    364		}
    365		dev_warn(&intf->dev,
    366			 "dev can't take %u byte packets (max %u), "
    367			 "adjusting MTU to %u\n",
    368			 dev->hard_mtu, tmp, tmp - net->hard_header_len);
    369		dev->hard_mtu = tmp;
    370		net->mtu = dev->hard_mtu - net->hard_header_len;
    371	}
    372
    373	/* REVISIT:  peripheral "alignment" request is ignored ... */
    374	dev_dbg(&intf->dev,
    375		"hard mtu %u (%u from dev), rx buflen %zu, align %d\n",
    376		dev->hard_mtu, tmp, dev->rx_urb_size,
    377		1 << le32_to_cpu(u.init_c->packet_alignment));
    378
    379	/* module has some device initialization code needs to be done right
    380	 * after RNDIS_INIT */
    381	if (dev->driver_info->early_init &&
    382			dev->driver_info->early_init(dev) != 0)
    383		goto halt_fail_and_release;
    384
    385	/* Check physical medium */
    386	phym = NULL;
    387	reply_len = sizeof *phym;
    388	retval = rndis_query(dev, intf, u.buf,
    389			     RNDIS_OID_GEN_PHYSICAL_MEDIUM,
    390			     reply_len, (void **)&phym, &reply_len);
    391	if (retval != 0 || !phym) {
    392		/* OID is optional so don't fail here. */
    393		phym_unspec = cpu_to_le32(RNDIS_PHYSICAL_MEDIUM_UNSPECIFIED);
    394		phym = &phym_unspec;
    395	}
    396	if ((flags & FLAG_RNDIS_PHYM_WIRELESS) &&
    397	    le32_to_cpup(phym) != RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
    398		netif_dbg(dev, probe, dev->net,
    399			  "driver requires wireless physical medium, but device is not\n");
    400		retval = -ENODEV;
    401		goto halt_fail_and_release;
    402	}
    403	if ((flags & FLAG_RNDIS_PHYM_NOT_WIRELESS) &&
    404	    le32_to_cpup(phym) == RNDIS_PHYSICAL_MEDIUM_WIRELESS_LAN) {
    405		netif_dbg(dev, probe, dev->net,
    406			  "driver requires non-wireless physical medium, but device is wireless.\n");
    407		retval = -ENODEV;
    408		goto halt_fail_and_release;
    409	}
    410
    411	/* Get designated host ethernet address */
    412	reply_len = ETH_ALEN;
    413	retval = rndis_query(dev, intf, u.buf,
    414			     RNDIS_OID_802_3_PERMANENT_ADDRESS,
    415			     48, (void **) &bp, &reply_len);
    416	if (unlikely(retval< 0)) {
    417		dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
    418		goto halt_fail_and_release;
    419	}
    420
    421	eth_hw_addr_set(net, bp);
    422
    423	/* set a nonzero filter to enable data transfers */
    424	memset(u.set, 0, sizeof *u.set);
    425	u.set->msg_type = cpu_to_le32(RNDIS_MSG_SET);
    426	u.set->msg_len = cpu_to_le32(4 + sizeof *u.set);
    427	u.set->oid = cpu_to_le32(RNDIS_OID_GEN_CURRENT_PACKET_FILTER);
    428	u.set->len = cpu_to_le32(4);
    429	u.set->offset = cpu_to_le32((sizeof *u.set) - 8);
    430	*(__le32 *)(u.buf + sizeof *u.set) = cpu_to_le32(RNDIS_DEFAULT_FILTER);
    431
    432	retval = rndis_command(dev, u.header, CONTROL_BUFFER_SIZE);
    433	if (unlikely(retval < 0)) {
    434		dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
    435		goto halt_fail_and_release;
    436	}
    437
    438	retval = 0;
    439
    440	kfree(u.buf);
    441	return retval;
    442
    443halt_fail_and_release:
    444	memset(u.halt, 0, sizeof *u.halt);
    445	u.halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
    446	u.halt->msg_len = cpu_to_le32(sizeof *u.halt);
    447	(void) rndis_command(dev, (void *)u.halt, CONTROL_BUFFER_SIZE);
    448fail_and_release:
    449	usb_set_intfdata(info->data, NULL);
    450	usb_driver_release_interface(driver_of(intf), info->data);
    451	info->data = NULL;
    452fail:
    453	kfree(u.buf);
    454	return retval;
    455}
    456EXPORT_SYMBOL_GPL(generic_rndis_bind);
    457
    458static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
    459{
    460	return generic_rndis_bind(dev, intf, FLAG_RNDIS_PHYM_NOT_WIRELESS);
    461}
    462
    463static int zte_rndis_bind(struct usbnet *dev, struct usb_interface *intf)
    464{
    465	int status = rndis_bind(dev, intf);
    466
    467	if (!status && (dev->net->dev_addr[0] & 0x02))
    468		eth_hw_addr_random(dev->net);
    469
    470	return status;
    471}
    472
    473void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
    474{
    475	struct rndis_halt	*halt;
    476
    477	/* try to clear any rndis state/activity (no i/o from stack!) */
    478	halt = kzalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
    479	if (halt) {
    480		halt->msg_type = cpu_to_le32(RNDIS_MSG_HALT);
    481		halt->msg_len = cpu_to_le32(sizeof *halt);
    482		(void) rndis_command(dev, (void *)halt, CONTROL_BUFFER_SIZE);
    483		kfree(halt);
    484	}
    485
    486	usbnet_cdc_unbind(dev, intf);
    487}
    488EXPORT_SYMBOL_GPL(rndis_unbind);
    489
    490/*
    491 * DATA -- host must not write zlps
    492 */
    493int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
    494{
    495	bool dst_mac_fixup;
    496
    497	/* This check is no longer done by usbnet */
    498	if (skb->len < dev->net->hard_header_len)
    499		return 0;
    500
    501	dst_mac_fixup = !!(dev->driver_info->data & RNDIS_DRIVER_DATA_DST_MAC_FIXUP);
    502
    503	/* peripheral may have batched packets to us... */
    504	while (likely(skb->len)) {
    505		struct rndis_data_hdr	*hdr = (void *)skb->data;
    506		struct sk_buff		*skb2;
    507		u32			msg_type, msg_len, data_offset, data_len;
    508
    509		msg_type = le32_to_cpu(hdr->msg_type);
    510		msg_len = le32_to_cpu(hdr->msg_len);
    511		data_offset = le32_to_cpu(hdr->data_offset);
    512		data_len = le32_to_cpu(hdr->data_len);
    513
    514		/* don't choke if we see oob, per-packet data, etc */
    515		if (unlikely(msg_type != RNDIS_MSG_PACKET || skb->len < msg_len
    516				|| (data_offset + data_len + 8) > msg_len)) {
    517			dev->net->stats.rx_frame_errors++;
    518			netdev_dbg(dev->net, "bad rndis message %d/%d/%d/%d, len %d\n",
    519				   le32_to_cpu(hdr->msg_type),
    520				   msg_len, data_offset, data_len, skb->len);
    521			return 0;
    522		}
    523		skb_pull(skb, 8 + data_offset);
    524
    525		/* at most one packet left? */
    526		if (likely((data_len - skb->len) <= sizeof *hdr)) {
    527			skb_trim(skb, data_len);
    528			break;
    529		}
    530
    531		/* try to return all the packets in the batch */
    532		skb2 = skb_clone(skb, GFP_ATOMIC);
    533		if (unlikely(!skb2))
    534			break;
    535		skb_pull(skb, msg_len - sizeof *hdr);
    536		skb_trim(skb2, data_len);
    537
    538		if (unlikely(dst_mac_fixup))
    539			usbnet_cdc_zte_rx_fixup(dev, skb2);
    540
    541		usbnet_skb_return(dev, skb2);
    542	}
    543
    544	/* caller will usbnet_skb_return the remaining packet */
    545	if (unlikely(dst_mac_fixup))
    546		usbnet_cdc_zte_rx_fixup(dev, skb);
    547
    548	return 1;
    549}
    550EXPORT_SYMBOL_GPL(rndis_rx_fixup);
    551
    552struct sk_buff *
    553rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
    554{
    555	struct rndis_data_hdr	*hdr;
    556	struct sk_buff		*skb2;
    557	unsigned		len = skb->len;
    558
    559	if (likely(!skb_cloned(skb))) {
    560		int	room = skb_headroom(skb);
    561
    562		/* enough head room as-is? */
    563		if (unlikely((sizeof *hdr) <= room))
    564			goto fill;
    565
    566		/* enough room, but needs to be readjusted? */
    567		room += skb_tailroom(skb);
    568		if (likely((sizeof *hdr) <= room)) {
    569			skb->data = memmove(skb->head + sizeof *hdr,
    570					    skb->data, len);
    571			skb_set_tail_pointer(skb, len);
    572			goto fill;
    573		}
    574	}
    575
    576	/* create a new skb, with the correct size (and tailpad) */
    577	skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
    578	dev_kfree_skb_any(skb);
    579	if (unlikely(!skb2))
    580		return skb2;
    581	skb = skb2;
    582
    583	/* fill out the RNDIS header.  we won't bother trying to batch
    584	 * packets; Linux minimizes wasted bandwidth through tx queues.
    585	 */
    586fill:
    587	hdr = __skb_push(skb, sizeof *hdr);
    588	memset(hdr, 0, sizeof *hdr);
    589	hdr->msg_type = cpu_to_le32(RNDIS_MSG_PACKET);
    590	hdr->msg_len = cpu_to_le32(skb->len);
    591	hdr->data_offset = cpu_to_le32(sizeof(*hdr) - 8);
    592	hdr->data_len = cpu_to_le32(len);
    593
    594	/* FIXME make the last packet always be short ... */
    595	return skb;
    596}
    597EXPORT_SYMBOL_GPL(rndis_tx_fixup);
    598
    599
    600static const struct driver_info	rndis_info = {
    601	.description =	"RNDIS device",
    602	.flags =	FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
    603	.bind =		rndis_bind,
    604	.unbind =	rndis_unbind,
    605	.status =	rndis_status,
    606	.rx_fixup =	rndis_rx_fixup,
    607	.tx_fixup =	rndis_tx_fixup,
    608};
    609
    610static const struct driver_info	rndis_poll_status_info = {
    611	.description =	"RNDIS device (poll status before control)",
    612	.flags =	FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
    613	.data =		RNDIS_DRIVER_DATA_POLL_STATUS,
    614	.bind =		rndis_bind,
    615	.unbind =	rndis_unbind,
    616	.status =	rndis_status,
    617	.rx_fixup =	rndis_rx_fixup,
    618	.tx_fixup =	rndis_tx_fixup,
    619};
    620
    621static const struct driver_info	zte_rndis_info = {
    622	.description =	"ZTE RNDIS device",
    623	.flags =	FLAG_ETHER | FLAG_POINTTOPOINT | FLAG_FRAMING_RN | FLAG_NO_SETINT,
    624	.data =		RNDIS_DRIVER_DATA_DST_MAC_FIXUP,
    625	.bind =		zte_rndis_bind,
    626	.unbind =	rndis_unbind,
    627	.status =	rndis_status,
    628	.rx_fixup =	rndis_rx_fixup,
    629	.tx_fixup =	rndis_tx_fixup,
    630};
    631
    632/*-------------------------------------------------------------------------*/
    633
    634static const struct usb_device_id	products [] = {
    635{
    636	/* 2Wire HomePortal 1000SW */
    637	USB_DEVICE_AND_INTERFACE_INFO(0x1630, 0x0042,
    638				      USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
    639	.driver_info = (unsigned long) &rndis_poll_status_info,
    640}, {
    641	/* Hytera Communications DMR radios' "Radio to PC Network" */
    642	USB_VENDOR_AND_INTERFACE_INFO(0x238b,
    643				      USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
    644	.driver_info = (unsigned long)&rndis_info,
    645}, {
    646	/* ZTE WWAN modules */
    647	USB_VENDOR_AND_INTERFACE_INFO(0x19d2,
    648				      USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
    649	.driver_info = (unsigned long)&zte_rndis_info,
    650}, {
    651	/* ZTE WWAN modules, ACM flavour */
    652	USB_VENDOR_AND_INTERFACE_INFO(0x19d2,
    653				      USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
    654	.driver_info = (unsigned long)&zte_rndis_info,
    655}, {
    656	/* RNDIS is MSFT's un-official variant of CDC ACM */
    657	USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
    658	.driver_info = (unsigned long) &rndis_info,
    659}, {
    660	/* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
    661	USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
    662	.driver_info = (unsigned long) &rndis_poll_status_info,
    663}, {
    664	/* RNDIS for tethering */
    665	USB_INTERFACE_INFO(USB_CLASS_WIRELESS_CONTROLLER, 1, 3),
    666	.driver_info = (unsigned long) &rndis_info,
    667}, {
    668	/* Novatel Verizon USB730L */
    669	USB_INTERFACE_INFO(USB_CLASS_MISC, 4, 1),
    670	.driver_info = (unsigned long) &rndis_info,
    671},
    672	{ },		// END
    673};
    674MODULE_DEVICE_TABLE(usb, products);
    675
    676static struct usb_driver rndis_driver = {
    677	.name =		"rndis_host",
    678	.id_table =	products,
    679	.probe =	usbnet_probe,
    680	.disconnect =	usbnet_disconnect,
    681	.suspend =	usbnet_suspend,
    682	.resume =	usbnet_resume,
    683	.disable_hub_initiated_lpm = 1,
    684};
    685
    686module_usb_driver(rndis_driver);
    687
    688MODULE_AUTHOR("David Brownell");
    689MODULE_DESCRIPTION("USB Host side RNDIS driver");
    690MODULE_LICENSE("GPL");