drivers/net/usb/cdc_mbim.c - third_party/linux - Git at Google

 /*
  * Copyright (c) 2012  Smith Micro Software, Inc.
  * Copyright (c) 2012  Bjørn Mork <bjorn@mork.no>
  *
  * This driver is based on and reuse most of cdc_ncm, which is
  * Copyright (C) ST-Ericsson 2010-2012
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  */

 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
 #include <linux/if_vlan.h>
 #include <linux/ip.h>
 #include <linux/mii.h>
 #include <linux/usb.h>
 #include <linux/usb/cdc.h>
 #include <linux/usb/usbnet.h>
 #include <linux/usb/cdc-wdm.h>
 #include <linux/usb/cdc_ncm.h>
 #include <net/ipv6.h>
 #include <net/addrconf.h>

 /* driver specific data - must match cdc_ncm usage */
 struct cdc_mbim_state {
 	struct cdc_ncm_ctx *ctx;
 	atomic_t pmcount;
 	struct usb_driver *subdriver;
 	struct usb_interface *control;
 	struct usb_interface *data;
 };

 /* using a counter to merge subdriver requests with our own into a combined state */
 static int cdc_mbim_manage_power(struct usbnet *dev, int on)
 {
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	int rv = 0;

 	dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(&info->pmcount), on);

 	if ((on && atomic_add_return(1, &info->pmcount) == 1) || (!on && atomic_dec_and_test(&info->pmcount))) {
 		/* need autopm_get/put here to ensure the usbcore sees the new value */
 		rv = usb_autopm_get_interface(dev->intf);
 		dev->intf->needs_remote_wakeup = on;
 		if (!rv)
 			usb_autopm_put_interface(dev->intf);
 	}
 	return 0;
 }

 static int cdc_mbim_wdm_manage_power(struct usb_interface *intf, int status)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);

 	/* can be called while disconnecting */
 	if (!dev)
 		return 0;

 	return cdc_mbim_manage_power(dev, status);
 }


 static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct cdc_ncm_ctx *ctx;
 	struct usb_driver *subdriver = ERR_PTR(-ENODEV);
 	int ret = -ENODEV;
 	u8 data_altsetting = cdc_ncm_select_altsetting(dev, intf);
 	struct cdc_mbim_state *info = (void *)&dev->data;

 	/* Probably NCM, defer for cdc_ncm_bind */
 	if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
 		goto err;

 	ret = cdc_ncm_bind_common(dev, intf, data_altsetting);
 	if (ret)
 		goto err;

 	ctx = info->ctx;

 	/* The MBIM descriptor and the status endpoint are required */
 	if (ctx->mbim_desc && dev->status)
 		subdriver = usb_cdc_wdm_register(ctx->control,
 						 &dev->status->desc,
 						 le16_to_cpu(ctx->mbim_desc->wMaxControlMessage),
 						 cdc_mbim_wdm_manage_power);
 	if (IS_ERR(subdriver)) {
 		ret = PTR_ERR(subdriver);
 		cdc_ncm_unbind(dev, intf);
 		goto err;
 	}

 	/* can't let usbnet use the interrupt endpoint */
 	dev->status = NULL;
 	info->subdriver = subdriver;

 	/* MBIM cannot do ARP */
 	dev->net->flags |= IFF_NOARP;

 	/* no need to put the VLAN tci in the packet headers */
 	dev->net->features |= NETIF_F_HW_VLAN_CTAG_TX;
 err:
 	return ret;
 }

 static void cdc_mbim_unbind(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;

 	/* disconnect subdriver from control interface */
 	if (info->subdriver && info->subdriver->disconnect)
 		info->subdriver->disconnect(ctx->control);
 	info->subdriver = NULL;

 	/* let NCM unbind clean up both control and data interface */
 	cdc_ncm_unbind(dev, intf);
 }


 static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 {
 	struct sk_buff *skb_out;
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;
 	__le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
 	u16 tci = 0;
 	u8 *c;

 	if (!ctx)
 		goto error;

 	if (skb) {
 		if (skb->len <= ETH_HLEN)
 			goto error;

 		/* mapping VLANs to MBIM sessions:
 		 *   no tag     => IPS session <0>
 		 *   1 - 255    => IPS session <vlanid>
 		 *   256 - 511  => DSS session <vlanid - 256>
 		 *   512 - 4095 => unsupported, drop
 		 */
 		vlan_get_tag(skb, &tci);

 		switch (tci & 0x0f00) {
 		case 0x0000: /* VLAN ID 0 - 255 */
 			/* verify that datagram is IPv4 or IPv6 */
 			skb_reset_mac_header(skb);
 			switch (eth_hdr(skb)->h_proto) {
 			case htons(ETH_P_IP):
 			case htons(ETH_P_IPV6):
 				break;
 			default:
 				goto error;
 			}
 			c = (u8 *)&sign;
 			c[3] = tci;
 			break;
 		case 0x0100: /* VLAN ID 256 - 511 */
 			sign = cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN);
 			c = (u8 *)&sign;
 			c[3] = tci;
 			break;
 		default:
 			netif_err(dev, tx_err, dev->net,
 				  "unsupported tci=0x%04x\n", tci);
 			goto error;
 		}
 		skb_pull(skb, ETH_HLEN);
 	}

 	spin_lock_bh(&ctx->mtx);
 	skb_out = cdc_ncm_fill_tx_frame(dev, skb, sign);
 	spin_unlock_bh(&ctx->mtx);
 	return skb_out;

 error:
 	if (skb)
 		dev_kfree_skb_any(skb);

 	return NULL;
 }

 /* Some devices are known to send Neigbor Solicitation messages and
  * require Neigbor Advertisement replies.  The IPv6 core will not
  * respond since IFF_NOARP is set, so we must handle them ourselves.
  */
 static void do_neigh_solicit(struct usbnet *dev, u8 *buf, u16 tci)
 {
 	struct ipv6hdr *iph = (void *)buf;
 	struct nd_msg *msg = (void *)(iph + 1);
 	struct net_device *netdev;
 	struct inet6_dev *in6_dev;
 	bool is_router;

 	/* we'll only respond to requests from unicast addresses to
 	 * our solicited node addresses.
 	 */
 	if (!ipv6_addr_is_solict_mult(&iph->daddr) ||
 	    !(ipv6_addr_type(&iph->saddr) & IPV6_ADDR_UNICAST))
 		return;

 	/* need to send the NA on the VLAN dev, if any */
 	if (tci)
 		netdev = __vlan_find_dev_deep(dev->net, htons(ETH_P_8021Q),
 					      tci);
 	else
 		netdev = dev->net;
 	if (!netdev)
 		return;

 	in6_dev = in6_dev_get(netdev);
 	if (!in6_dev)
 		return;
 	is_router = !!in6_dev->cnf.forwarding;
 	in6_dev_put(in6_dev);

 	/* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */
 	ipv6_stub->ndisc_send_na(netdev, NULL, &iph->saddr, &msg->target,
 				 is_router /* router */,
 				 true /* solicited */,
 				 false /* override */,
 				 true /* inc_opt */);
 }

 static bool is_neigh_solicit(u8 *buf, size_t len)
 {
 	struct ipv6hdr *iph = (void *)buf;
 	struct nd_msg *msg = (void *)(iph + 1);

 	return (len >= sizeof(struct ipv6hdr) + sizeof(struct nd_msg) &&
 		iph->nexthdr == IPPROTO_ICMPV6 &&
 		msg->icmph.icmp6_code == 0 &&
 		msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION);
 }


 static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_t len, u16 tci)
 {
 	__be16 proto = htons(ETH_P_802_3);
 	struct sk_buff *skb = NULL;

 	if (tci < 256) { /* IPS session? */
 		if (len < sizeof(struct iphdr))
 			goto err;

 		switch (*buf & 0xf0) {
 		case 0x40:
 			proto = htons(ETH_P_IP);
 			break;
 		case 0x60:
 			if (is_neigh_solicit(buf, len))
 				do_neigh_solicit(dev, buf, tci);
 			proto = htons(ETH_P_IPV6);
 			break;
 		default:
 			goto err;
 		}
 	}

 	skb = netdev_alloc_skb_ip_align(dev->net,  len + ETH_HLEN);
 	if (!skb)
 		goto err;

 	/* add an ethernet header */
 	skb_put(skb, ETH_HLEN);
 	skb_reset_mac_header(skb);
 	eth_hdr(skb)->h_proto = proto;
 	memset(eth_hdr(skb)->h_source, 0, ETH_ALEN);
 	memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);

 	/* add datagram */
 	memcpy(skb_put(skb, len), buf, len);

 	/* map MBIM session to VLAN */
 	if (tci)
 		vlan_put_tag(skb, htons(ETH_P_8021Q), tci);
 err:
 	return skb;
 }

 static int cdc_mbim_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 {
 	struct sk_buff *skb;
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;
 	int len;
 	int nframes;
 	int x;
 	int offset;
 	struct usb_cdc_ncm_ndp16 *ndp16;
 	struct usb_cdc_ncm_dpe16 *dpe16;
 	int ndpoffset;
 	int loopcount = 50; /* arbitrary max preventing infinite loop */
 	u8 *c;
 	u16 tci;

 	ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
 	if (ndpoffset < 0)
 		goto error;

 next_ndp:
 	nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
 	if (nframes < 0)
 		goto error;

 	ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);

 	switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
 	case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
 		c = (u8 *)&ndp16->dwSignature;
 		tci = c[3];
 		break;
 	case cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN):
 		c = (u8 *)&ndp16->dwSignature;
 		tci = c[3] + 256;
 		break;
 	default:
 		netif_dbg(dev, rx_err, dev->net,
 			  "unsupported NDP signature <0x%08x>\n",
 			  le32_to_cpu(ndp16->dwSignature));
 		goto err_ndp;

 	}

 	dpe16 = ndp16->dpe16;
 	for (x = 0; x < nframes; x++, dpe16++) {
 		offset = le16_to_cpu(dpe16->wDatagramIndex);
 		len = le16_to_cpu(dpe16->wDatagramLength);

 		/*
 		 * CDC NCM ch. 3.7
 		 * All entries after first NULL entry are to be ignored
 		 */
 		if ((offset == 0) || (len == 0)) {
 			if (!x)
 				goto err_ndp; /* empty NTB */
 			break;
 		}

 		/* sanity checking */
 		if (((offset + len) > skb_in->len) || (len > ctx->rx_max)) {
 			netif_dbg(dev, rx_err, dev->net,
 				  "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
 				  x, offset, len, skb_in);
 			if (!x)
 				goto err_ndp;
 			break;
 		} else {
 			skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
 			if (!skb)
 				goto error;
 			usbnet_skb_return(dev, skb);
 		}
 	}
 err_ndp:
 	/* are there more NDPs to process? */
 	ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
 	if (ndpoffset && loopcount--)
 		goto next_ndp;

 	return 1;
 error:
 	return 0;
 }

 static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	int ret = -ENODEV;
 	struct usbnet *dev = usb_get_intfdata(intf);
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;

 	if (!ctx)
 		goto error;

 	/*
 	 * Both usbnet_suspend() and subdriver->suspend() MUST return 0
 	 * in system sleep context, otherwise, the resume callback has
 	 * to recover device from previous suspend failure.
 	 */
 	ret = usbnet_suspend(intf, message);
 	if (ret < 0)
 		goto error;

 	if (intf == ctx->control && info->subdriver && info->subdriver->suspend)
 		ret = info->subdriver->suspend(intf, message);
 	if (ret < 0)
 		usbnet_resume(intf);

 error:
 	return ret;
 }

 static int cdc_mbim_resume(struct usb_interface *intf)
 {
 	int  ret = 0;
 	struct usbnet *dev = usb_get_intfdata(intf);
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;
 	bool callsub = (intf == ctx->control && info->subdriver && info->subdriver->resume);

 	if (callsub)
 		ret = info->subdriver->resume(intf);
 	if (ret < 0)
 		goto err;
 	ret = usbnet_resume(intf);
 	if (ret < 0 && callsub)
 		info->subdriver->suspend(intf, PMSG_SUSPEND);
 err:
 	return ret;
 }

 static const struct driver_info cdc_mbim_info = {
 	.description = "CDC MBIM",
 	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
 	.bind = cdc_mbim_bind,
 	.unbind = cdc_mbim_unbind,
 	.manage_power = cdc_mbim_manage_power,
 	.rx_fixup = cdc_mbim_rx_fixup,
 	.tx_fixup = cdc_mbim_tx_fixup,
 };

 /* MBIM and NCM devices should not need a ZLP after NTBs with
  * dwNtbOutMaxSize length. Nevertheless, a number of devices from
  * different vendor IDs will fail unless we send ZLPs, forcing us
  * to make this the default.
  *
  * This default may cause a performance penalty for spec conforming
  * devices wanting to take advantage of optimizations possible without
  * ZLPs.  A whitelist is added in an attempt to avoid this for devices
  * known to conform to the MBIM specification.
  *
  * All known devices supporting NCM compatibility mode are also
  * conforming to the NCM and MBIM specifications. For this reason, the
  * NCM subclass entry is also in the ZLP whitelist.
  */
 static const struct driver_info cdc_mbim_info_zlp = {
 	.description = "CDC MBIM",
 	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN | FLAG_SEND_ZLP,
 	.bind = cdc_mbim_bind,
 	.unbind = cdc_mbim_unbind,
 	.manage_power = cdc_mbim_manage_power,
 	.rx_fixup = cdc_mbim_rx_fixup,
 	.tx_fixup = cdc_mbim_tx_fixup,
 };

 static const struct usb_device_id mbim_devs[] = {
 	/* This duplicate NCM entry is intentional. MBIM devices can
 	 * be disguised as NCM by default, and this is necessary to
 	 * allow us to bind the correct driver_info to such devices.
 	 *
 	 * bind() will sort out this for us, selecting the correct
 	 * entry and reject the other
 	 */
 	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info,
 	},
 	/* ZLP conformance whitelist: All Ericsson MBIM devices */
 	{ USB_VENDOR_AND_INTERFACE_INFO(0x0bdb, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info,
 	},
 	/* default entry */
 	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info_zlp,
 	},
 	{
 	},
 };
 MODULE_DEVICE_TABLE(usb, mbim_devs);

 static struct usb_driver cdc_mbim_driver = {
 	.name = "cdc_mbim",
 	.id_table = mbim_devs,
 	.probe = usbnet_probe,
 	.disconnect = usbnet_disconnect,
 	.suspend = cdc_mbim_suspend,
 	.resume = cdc_mbim_resume,
 	.reset_resume =	cdc_mbim_resume,
 	.supports_autosuspend = 1,
 	.disable_hub_initiated_lpm = 1,
 };
 module_usb_driver(cdc_mbim_driver);

 MODULE_AUTHOR("Greg Suarez <gsuarez@smithmicro.com>");
 MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
 MODULE_DESCRIPTION("USB CDC MBIM host driver");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (c) 2012 Smith Micro Software, Inc.
	* Copyright (c) 2012 Bjørn Mork <bjorn@mork.no>
	*
	* This driver is based on and reuse most of cdc_ncm, which is
	* Copyright (C) ST-Ericsson 2010-2012
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*/

	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/ethtool.h>
	#include <linux/if_vlan.h>
	#include <linux/ip.h>
	#include <linux/mii.h>
	#include <linux/usb.h>
	#include <linux/usb/cdc.h>
	#include <linux/usb/usbnet.h>
	#include <linux/usb/cdc-wdm.h>
	#include <linux/usb/cdc_ncm.h>
	#include <net/ipv6.h>
	#include <net/addrconf.h>

	/* driver specific data - must match cdc_ncm usage */
	struct cdc_mbim_state {
	struct cdc_ncm_ctx *ctx;
	atomic_t pmcount;
	struct usb_driver *subdriver;
	struct usb_interface *control;
	struct usb_interface *data;
	};

	/* using a counter to merge subdriver requests with our own into a combined state */
	static int cdc_mbim_manage_power(struct usbnet *dev, int on)
	{
	struct cdc_mbim_state info = (void )&dev->data;
	int rv = 0;

	dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(&info->pmcount), on);

	if ((on && atomic_add_return(1, &info->pmcount) == 1) \|\| (!on && atomic_dec_and_test(&info->pmcount))) {
	/* need autopm_get/put here to ensure the usbcore sees the new value */
	rv = usb_autopm_get_interface(dev->intf);
	dev->intf->needs_remote_wakeup = on;
	if (!rv)
	usb_autopm_put_interface(dev->intf);
	}
	return 0;
	}

	static int cdc_mbim_wdm_manage_power(struct usb_interface *intf, int status)
	{
	struct usbnet *dev = usb_get_intfdata(intf);

	/* can be called while disconnecting */
	if (!dev)
	return 0;

	return cdc_mbim_manage_power(dev, status);
	}


	static int cdc_mbim_bind(struct usbnet dev, struct usb_interface intf)
	{
	struct cdc_ncm_ctx *ctx;
	struct usb_driver *subdriver = ERR_PTR(-ENODEV);
	int ret = -ENODEV;
	u8 data_altsetting = cdc_ncm_select_altsetting(dev, intf);
	struct cdc_mbim_state info = (void )&dev->data;

	/* Probably NCM, defer for cdc_ncm_bind */
	if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
	goto err;

	ret = cdc_ncm_bind_common(dev, intf, data_altsetting);
	if (ret)
	goto err;

	ctx = info->ctx;

	/* The MBIM descriptor and the status endpoint are required */
	if (ctx->mbim_desc && dev->status)
	subdriver = usb_cdc_wdm_register(ctx->control,
	&dev->status->desc,
	le16_to_cpu(ctx->mbim_desc->wMaxControlMessage),
	cdc_mbim_wdm_manage_power);
	if (IS_ERR(subdriver)) {
	ret = PTR_ERR(subdriver);
	cdc_ncm_unbind(dev, intf);
	goto err;
	}

	/* can't let usbnet use the interrupt endpoint */
	dev->status = NULL;
	info->subdriver = subdriver;

	/* MBIM cannot do ARP */
	dev->net->flags \|= IFF_NOARP;

	/* no need to put the VLAN tci in the packet headers */
	dev->net->features \|= NETIF_F_HW_VLAN_CTAG_TX;
	err:
	return ret;
	}

	static void cdc_mbim_unbind(struct usbnet dev, struct usb_interface intf)
	{
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;

	/* disconnect subdriver from control interface */
	if (info->subdriver && info->subdriver->disconnect)
	info->subdriver->disconnect(ctx->control);
	info->subdriver = NULL;

	/* let NCM unbind clean up both control and data interface */
	cdc_ncm_unbind(dev, intf);
	}


	static struct sk_buff cdc_mbim_tx_fixup(struct usbnet dev, struct sk_buff *skb, gfp_t flags)
	{
	struct sk_buff *skb_out;
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;
	__le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
	u16 tci = 0;
	u8 *c;

	if (!ctx)
	goto error;

	if (skb) {
	if (skb->len <= ETH_HLEN)
	goto error;

	/* mapping VLANs to MBIM sessions:
	* no tag => IPS session <0>
	* 1 - 255 => IPS session <vlanid>
	* 256 - 511 => DSS session <vlanid - 256>
	* 512 - 4095 => unsupported, drop
	*/
	vlan_get_tag(skb, &tci);

	switch (tci & 0x0f00) {
	case 0x0000: /* VLAN ID 0 - 255 */
	/* verify that datagram is IPv4 or IPv6 */
	skb_reset_mac_header(skb);
	switch (eth_hdr(skb)->h_proto) {
	case htons(ETH_P_IP):
	case htons(ETH_P_IPV6):
	break;
	default:
	goto error;
	}
	c = (u8 *)&sign;
	c[3] = tci;
	break;
	case 0x0100: /* VLAN ID 256 - 511 */
	sign = cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN);
	c = (u8 *)&sign;
	c[3] = tci;
	break;
	default:
	netif_err(dev, tx_err, dev->net,
	"unsupported tci=0x%04x\n", tci);
	goto error;
	}
	skb_pull(skb, ETH_HLEN);
	}

	spin_lock_bh(&ctx->mtx);
	skb_out = cdc_ncm_fill_tx_frame(dev, skb, sign);
	spin_unlock_bh(&ctx->mtx);
	return skb_out;

	error:
	if (skb)
	dev_kfree_skb_any(skb);

	return NULL;
	}

	/* Some devices are known to send Neigbor Solicitation messages and
	* require Neigbor Advertisement replies. The IPv6 core will not
	* respond since IFF_NOARP is set, so we must handle them ourselves.
	*/
	static void do_neigh_solicit(struct usbnet dev, u8 buf, u16 tci)
	{
	struct ipv6hdr iph = (void )buf;
	struct nd_msg msg = (void )(iph + 1);
	struct net_device *netdev;
	struct inet6_dev *in6_dev;
	bool is_router;

	/* we'll only respond to requests from unicast addresses to
	* our solicited node addresses.
	*/
	if (!ipv6_addr_is_solict_mult(&iph->daddr) \|\|
	!(ipv6_addr_type(&iph->saddr) & IPV6_ADDR_UNICAST))
	return;

	/* need to send the NA on the VLAN dev, if any */
	if (tci)
	netdev = __vlan_find_dev_deep(dev->net, htons(ETH_P_8021Q),
	tci);
	else
	netdev = dev->net;
	if (!netdev)
	return;

	in6_dev = in6_dev_get(netdev);
	if (!in6_dev)
	return;
	is_router = !!in6_dev->cnf.forwarding;
	in6_dev_put(in6_dev);

	/* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */
	ipv6_stub->ndisc_send_na(netdev, NULL, &iph->saddr, &msg->target,
	is_router /* router */,
	true /* solicited */,
	false /* override */,
	true /* inc_opt */);
	}

	static bool is_neigh_solicit(u8 *buf, size_t len)
	{
	struct ipv6hdr iph = (void )buf;
	struct nd_msg msg = (void )(iph + 1);

	return (len >= sizeof(struct ipv6hdr) + sizeof(struct nd_msg) &&
	iph->nexthdr == IPPROTO_ICMPV6 &&
	msg->icmph.icmp6_code == 0 &&
	msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION);
	}


	static struct sk_buff cdc_mbim_process_dgram(struct usbnet dev, u8 *buf, size_t len, u16 tci)
	{
	__be16 proto = htons(ETH_P_802_3);
	struct sk_buff *skb = NULL;

	if (tci < 256) { /* IPS session? */
	if (len < sizeof(struct iphdr))
	goto err;

	switch (*buf & 0xf0) {
	case 0x40:
	proto = htons(ETH_P_IP);
	break;
	case 0x60:
	if (is_neigh_solicit(buf, len))
	do_neigh_solicit(dev, buf, tci);
	proto = htons(ETH_P_IPV6);
	break;
	default:
	goto err;
	}
	}

	skb = netdev_alloc_skb_ip_align(dev->net, len + ETH_HLEN);
	if (!skb)
	goto err;

	/* add an ethernet header */
	skb_put(skb, ETH_HLEN);
	skb_reset_mac_header(skb);
	eth_hdr(skb)->h_proto = proto;
	memset(eth_hdr(skb)->h_source, 0, ETH_ALEN);
	memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);

	/* add datagram */
	memcpy(skb_put(skb, len), buf, len);

	/* map MBIM session to VLAN */
	if (tci)
	vlan_put_tag(skb, htons(ETH_P_8021Q), tci);
	err:
	return skb;
	}

	static int cdc_mbim_rx_fixup(struct usbnet dev, struct sk_buff skb_in)
	{
	struct sk_buff *skb;
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;
	int len;
	int nframes;
	int x;
	int offset;
	struct usb_cdc_ncm_ndp16 *ndp16;
	struct usb_cdc_ncm_dpe16 *dpe16;
	int ndpoffset;
	int loopcount = 50; /* arbitrary max preventing infinite loop */
	u8 *c;
	u16 tci;

	ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
	if (ndpoffset < 0)
	goto error;

	next_ndp:
	nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
	if (nframes < 0)
	goto error;

	ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);

	switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
	case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
	c = (u8 *)&ndp16->dwSignature;
	tci = c[3];
	break;
	case cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN):
	c = (u8 *)&ndp16->dwSignature;
	tci = c[3] + 256;
	break;
	default:
	netif_dbg(dev, rx_err, dev->net,
	"unsupported NDP signature <0x%08x>\n",
	le32_to_cpu(ndp16->dwSignature));
	goto err_ndp;

	}

	dpe16 = ndp16->dpe16;
	for (x = 0; x < nframes; x++, dpe16++) {
	offset = le16_to_cpu(dpe16->wDatagramIndex);
	len = le16_to_cpu(dpe16->wDatagramLength);

	/*
	* CDC NCM ch. 3.7
	* All entries after first NULL entry are to be ignored
	*/
	if ((offset == 0) \|\| (len == 0)) {
	if (!x)
	goto err_ndp; /* empty NTB */
	break;
	}

	/* sanity checking */
	if (((offset + len) > skb_in->len) \|\| (len > ctx->rx_max)) {
	netif_dbg(dev, rx_err, dev->net,
	"invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
	x, offset, len, skb_in);
	if (!x)
	goto err_ndp;
	break;
	} else {
	skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
	if (!skb)
	goto error;
	usbnet_skb_return(dev, skb);
	}
	}
	err_ndp:
	/* are there more NDPs to process? */
	ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
	if (ndpoffset && loopcount--)
	goto next_ndp;

	return 1;
	error:
	return 0;
	}

	static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
	{
	int ret = -ENODEV;
	struct usbnet *dev = usb_get_intfdata(intf);
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;

	if (!ctx)
	goto error;

	/*
	* Both usbnet_suspend() and subdriver->suspend() MUST return 0
	* in system sleep context, otherwise, the resume callback has
	* to recover device from previous suspend failure.
	*/
	ret = usbnet_suspend(intf, message);
	if (ret < 0)
	goto error;

	if (intf == ctx->control && info->subdriver && info->subdriver->suspend)
	ret = info->subdriver->suspend(intf, message);
	if (ret < 0)
	usbnet_resume(intf);

	error:
	return ret;
	}

	static int cdc_mbim_resume(struct usb_interface *intf)
	{
	int ret = 0;
	struct usbnet *dev = usb_get_intfdata(intf);
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;
	bool callsub = (intf == ctx->control && info->subdriver && info->subdriver->resume);

	if (callsub)
	ret = info->subdriver->resume(intf);
	if (ret < 0)
	goto err;
	ret = usbnet_resume(intf);
	if (ret < 0 && callsub)
	info->subdriver->suspend(intf, PMSG_SUSPEND);
	err:
	return ret;
	}

	static const struct driver_info cdc_mbim_info = {
	.description = "CDC MBIM",
	.flags = FLAG_NO_SETINT \| FLAG_MULTI_PACKET \| FLAG_WWAN,
	.bind = cdc_mbim_bind,
	.unbind = cdc_mbim_unbind,
	.manage_power = cdc_mbim_manage_power,
	.rx_fixup = cdc_mbim_rx_fixup,
	.tx_fixup = cdc_mbim_tx_fixup,
	};

	/* MBIM and NCM devices should not need a ZLP after NTBs with
	* dwNtbOutMaxSize length. Nevertheless, a number of devices from
	* different vendor IDs will fail unless we send ZLPs, forcing us
	* to make this the default.
	*
	* This default may cause a performance penalty for spec conforming
	* devices wanting to take advantage of optimizations possible without
	* ZLPs. A whitelist is added in an attempt to avoid this for devices
	* known to conform to the MBIM specification.
	*
	* All known devices supporting NCM compatibility mode are also
	* conforming to the NCM and MBIM specifications. For this reason, the
	* NCM subclass entry is also in the ZLP whitelist.
	*/
	static const struct driver_info cdc_mbim_info_zlp = {
	.description = "CDC MBIM",
	.flags = FLAG_NO_SETINT \| FLAG_MULTI_PACKET \| FLAG_WWAN \| FLAG_SEND_ZLP,
	.bind = cdc_mbim_bind,
	.unbind = cdc_mbim_unbind,
	.manage_power = cdc_mbim_manage_power,
	.rx_fixup = cdc_mbim_rx_fixup,
	.tx_fixup = cdc_mbim_tx_fixup,
	};

	static const struct usb_device_id mbim_devs[] = {
	/* This duplicate NCM entry is intentional. MBIM devices can
	* be disguised as NCM by default, and this is necessary to
	* allow us to bind the correct driver_info to such devices.
	*
	* bind() will sort out this for us, selecting the correct
	* entry and reject the other
	*/
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info,
	},
	/* ZLP conformance whitelist: All Ericsson MBIM devices */
	{ USB_VENDOR_AND_INTERFACE_INFO(0x0bdb, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info,
	},
	/* default entry */
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info_zlp,
	},
	{
	},
	};
	MODULE_DEVICE_TABLE(usb, mbim_devs);

	static struct usb_driver cdc_mbim_driver = {
	.name = "cdc_mbim",
	.id_table = mbim_devs,
	.probe = usbnet_probe,
	.disconnect = usbnet_disconnect,
	.suspend = cdc_mbim_suspend,
	.resume = cdc_mbim_resume,
	.reset_resume = cdc_mbim_resume,
	.supports_autosuspend = 1,
	.disable_hub_initiated_lpm = 1,
	};
	module_usb_driver(cdc_mbim_driver);

	MODULE_AUTHOR("Greg Suarez <gsuarez@smithmicro.com>");
	MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
	MODULE_DESCRIPTION("USB CDC MBIM host driver");
	MODULE_LICENSE("GPL");