path: root/drivers/net/usb/cdc_mbim.c

/*
 * 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<