rndis_host.c

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					dev_dbg(&info->control->dev,
						"rndis keepalive err %d\n",
						retval);
				}
				break;
			default:
				dev_dbg(&info->control->dev,
					"unexpected rndis msg %08x len %d\n",
					le32_to_cpu(buf->msg_type), msg_len);
			}
		} else {
			/* device probably issued a protocol stall; ignore */
			dev_dbg(&info->control->dev,
				"rndis response error, code %d\n", retval);
		}
		msleep(2);
	}
	dev_dbg(&info->control->dev, "rndis response timeout\n");
	return -ETIMEDOUT;
}

/*
 * rndis_query:
 *
 * Performs a query for @oid along with 0 or more bytes of payload as
 * specified by @in_len. If @reply_len is not set to -1 then the reply
 * length is checked against this value, resulting in an error if it
 * doesn't match.
 *
 * NOTE: Adding a payload exactly or greater than the size of the expected
 * response payload is an evident requirement MSFT added for ActiveSync.
 *
 * The only exception is for OIDs that return a variably sized response,
 * in which case no payload should be added.  This undocumented (and
 * nonsensical!) issue was found by sniffing protocol requests from the
 * ActiveSync 4.1 Windows driver.
 */
static int rndis_query(struct usbnet *dev, struct usb_interface *intf,
		void *buf, u32 oid, u32 in_len,
		void **reply, int *reply_len)
{
	int retval;
	union {
		void			*buf;
		struct rndis_msg_hdr	*header;
		struct rndis_query	*get;
		struct rndis_query_c	*get_c;
	} u;
	u32 off, len;

	u.buf = buf;

	memset(u.get, 0, sizeof *u.get + in_len);
	u.get->msg_type = RNDIS_MSG_QUERY;
	u.get->msg_len = cpu_to_le32(sizeof *u.get + in_len);
	u.get->oid = oid;
	u.get->len = cpu_to_le32(in_len);
	u.get->offset = ccpu2(20);

	retval = rndis_command(dev, u.header);
	if (unlikely(retval < 0)) {
		dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) failed, %d\n",
				oid, retval);
		return retval;
	}

	off = le32_to_cpu(u.get_c->offset);
	len = le32_to_cpu(u.get_c->len);
	if (unlikely((8 + off + len) > CONTROL_BUFFER_SIZE))
		goto response_error;

	if (*reply_len != -1 && len != *reply_len)
		goto response_error;

	*reply = (unsigned char *) &u.get_c->request_id + off;
	*reply_len = len;

	return retval;

response_error:
	dev_err(&intf->dev, "RNDIS_MSG_QUERY(0x%08x) "
			"invalid response - off %d len %d\n",
		oid, off, len);
	return -EDOM;
}

static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
{
	int			retval;
	struct net_device	*net = dev->net;
	struct cdc_state	*info = (void *) &dev->data;
	union {
		void			*buf;
		struct rndis_msg_hdr	*header;
		struct rndis_init	*init;
		struct rndis_init_c	*init_c;
		struct rndis_query	*get;
		struct rndis_query_c	*get_c;
		struct rndis_set	*set;
		struct rndis_set_c	*set_c;
	} u;
	u32			tmp;
	int			reply_len;
	unsigned char		*bp;

	/* we can't rely on i/o from stack working, or stack allocation */
	u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
	if (!u.buf)
		return -ENOMEM;
	retval = usbnet_generic_cdc_bind(dev, intf);
	if (retval < 0)
		goto fail;

	u.init->msg_type = RNDIS_MSG_INIT;
	u.init->msg_len = ccpu2(sizeof *u.init);
	u.init->major_version = ccpu2(1);
	u.init->minor_version = ccpu2(0);

	/* max transfer (in spec) is 0x4000 at full speed, but for
	 * TX we'll stick to one Ethernet packet plus RNDIS framing.
	 * For RX we handle drivers that zero-pad to end-of-packet.
	 * Don't let userspace change these settings.
	 *
	 * NOTE: there still seems to be wierdness here, as if we need
	 * to do some more things to make sure WinCE targets accept this.
	 * They default to jumbograms of 8KB or 16KB, which is absurd
	 * for such low data rates and which is also more than Linux
	 * can usually expect to allocate for SKB data...
	 */
	net->hard_header_len += sizeof (struct rndis_data_hdr);
	dev->hard_mtu = net->mtu + net->hard_header_len;

	dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
	dev->rx_urb_size &= ~(dev->maxpacket - 1);
	u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);

	net->change_mtu = NULL;
	retval = rndis_command(dev, u.header);
	if (unlikely(retval < 0)) {
		/* it might not even be an RNDIS device!! */
		dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
		goto fail_and_release;
	}
	tmp = le32_to_cpu(u.init_c->max_transfer_size);
	if (tmp < dev->hard_mtu) {
		if (tmp <= net->hard_header_len) {
			dev_err(&intf->dev,
				"dev can't take %u byte packets (max %u)\n",
				dev->hard_mtu, tmp);
			retval = -EINVAL;
			goto fail_and_release;
		}
		dev->hard_mtu = tmp;
		net->mtu = dev->hard_mtu - net->hard_header_len;
		dev_warn(&intf->dev,
			 "dev can't take %u byte packets (max %u), "
			 "adjusting MTU to %u\n",
			 dev->hard_mtu, tmp, net->mtu);
	}

	/* REVISIT:  peripheral "alignment" request is ignored ... */
	dev_dbg(&intf->dev,
		"hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
		dev->hard_mtu, tmp, dev->rx_urb_size,
		1 << le32_to_cpu(u.init_c->packet_alignment));

	/* Get designated host ethernet address */
	reply_len = ETH_ALEN;
	retval = rndis_query(dev, intf, u.buf, OID_802_3_PERMANENT_ADDRESS,
			48, (void **) &bp, &reply_len);
	if (unlikely(retval< 0)) {
		dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval);
		goto fail_and_release;
	}
	memcpy(net->dev_addr, bp, ETH_ALEN);

	/* set a nonzero filter to enable data transfers */
	memset(u.set, 0, sizeof *u.set);
	u.set->msg_type = RNDIS_MSG_SET;
	u.set->msg_len = ccpu2(4 + sizeof *u.set);
	u.set->oid = OID_GEN_CURRENT_PACKET_FILTER;
	u.set->len = ccpu2(4);
	u.set->offset = ccpu2((sizeof *u.set) - 8);
	*(__le32 *)(u.buf + sizeof *u.set) = ccpu2(DEFAULT_FILTER);

	retval = rndis_command(dev, u.header);
	if (unlikely(retval < 0)) {
		dev_err(&intf->dev, "rndis set packet filter, %d\n", retval);
		goto fail_and_release;
	}

	retval = 0;

	kfree(u.buf);
	return retval;

fail_and_release:
	usb_set_intfdata(info->data, NULL);
	usb_driver_release_interface(driver_of(intf), info->data);
	info->data = NULL;
fail:
	kfree(u.buf);
	return retval;
}

static void rndis_unbind(struct usbnet *dev, struct usb_interface *intf)
{
	struct rndis_halt	*halt;

	/* try to clear any rndis state/activity (no i/o from stack!) */
	halt = kzalloc(sizeof *halt, GFP_KERNEL);
	if (halt) {
		halt->msg_type = RNDIS_MSG_HALT;
		halt->msg_len = ccpu2(sizeof *halt);
		(void) rndis_command(dev, (void *)halt);
		kfree(halt);
	}

	return usbnet_cdc_unbind(dev, intf);
}

/*
 * DATA -- host must not write zlps
 */
static int rndis_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
{
	/* peripheral may have batched packets to us... */
	while (likely(skb->len)) {
		struct rndis_data_hdr	*hdr = (void *)skb->data;
		struct sk_buff		*skb2;
		u32			msg_len, data_offset, data_len;

		msg_len = le32_to_cpu(hdr->msg_len);
		data_offset = le32_to_cpu(hdr->data_offset);
		data_len = le32_to_cpu(hdr->data_len);

		/* don't choke if we see oob, per-packet data, etc */
		if (unlikely(hdr->msg_type != RNDIS_MSG_PACKET
				|| skb->len < msg_len
				|| (data_offset + data_len + 8) > msg_len)) {
			dev->stats.rx_frame_errors++;
			devdbg(dev, "bad rndis message %d/%d/%d/%d, len %d",
				le32_to_cpu(hdr->msg_type),
				msg_len, data_offset, data_len, skb->len);
			return 0;
		}
		skb_pull(skb, 8 + data_offset);

		/* at most one packet left? */
		if (likely((data_len - skb->len) <= sizeof *hdr)) {
			skb_trim(skb, data_len);
			break;
		}

		/* try to return all the packets in the batch */
		skb2 = skb_clone(skb, GFP_ATOMIC);
		if (unlikely(!skb2))
			break;
		skb_pull(skb, msg_len - sizeof *hdr);
		skb_trim(skb2, data_len);
		usbnet_skb_return(dev, skb2);
	}

	/* caller will usbnet_skb_return the remaining packet */
	return 1;
}

static struct sk_buff *
rndis_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
	struct rndis_data_hdr	*hdr;
	struct sk_buff		*skb2;
	unsigned		len = skb->len;

	if (likely(!skb_cloned(skb))) {
		int	room = skb_headroom(skb);

		/* enough head room as-is? */
		if (unlikely((sizeof *hdr) <= room))
			goto fill;

		/* enough room, but needs to be readjusted? */
		room += skb_tailroom(skb);
		if (likely((sizeof *hdr) <= room)) {
			skb->data = memmove(skb->head + sizeof *hdr,
					    skb->data, len);
			skb_set_tail_pointer(skb, len);
			goto fill;
		}
	}

	/* create a new skb, with the correct size (and tailpad) */
	skb2 = skb_copy_expand(skb, sizeof *hdr, 1, flags);
	dev_kfree_skb_any(skb);
	if (unlikely(!skb2))
		return skb2;
	skb = skb2;

	/* fill out the RNDIS header.  we won't bother trying to batch
	 * packets; Linux minimizes wasted bandwidth through tx queues.
	 */
fill:
	hdr = (void *) __skb_push(skb, sizeof *hdr);
	memset(hdr, 0, sizeof *hdr);
	hdr->msg_type = RNDIS_MSG_PACKET;
	hdr->msg_len = cpu_to_le32(skb->len);
	hdr->data_offset = ccpu2(sizeof(*hdr) - 8);
	hdr->data_len = cpu_to_le32(len);

	/* FIXME make the last packet always be short ... */
	return skb;
}


static const struct driver_info	rndis_info = {
	.description =	"RNDIS device",
	.flags =	FLAG_ETHER | FLAG_FRAMING_RN | FLAG_NO_SETINT,
	.bind =		rndis_bind,
	.unbind =	rndis_unbind,
	.status =	rndis_status,
	.rx_fixup =	rndis_rx_fixup,
	.tx_fixup =	rndis_tx_fixup,
};

#undef ccpu2


/*-------------------------------------------------------------------------*/

static const struct usb_device_id	products [] = {
{
	/* RNDIS is MSFT's un-official variant of CDC ACM */
	USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
	.driver_info = (unsigned long) &rndis_info,
}, {
	/* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
	USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
	.driver_info = (unsigned long) &rndis_info,
},
	{ },		// END
};
MODULE_DEVICE_TABLE(usb, products);

static struct usb_driver rndis_driver = {
	.name =		"rndis_host",
	.id_table =	products,
	.probe =	usbnet_probe,
	.disconnect =	usbnet_disconnect,
	.suspend =	usbnet_suspend,
	.resume =	usbnet_resume,
};

static int __init rndis_init(void)
{
	return usb_register(&rndis_driver);
}
module_init(rndis_init);

static void __exit rndis_exit(void)
{
	usb_deregister(&rndis_driver);
}
module_exit(rndis_exit);

MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("USB Host side RNDIS driver");
MODULE_LICENSE("GPL");