/*

   * Copyright (c) 2009, Microsoft Corporation.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License along with

   * this program; if not, see <http://www.gnu.org/licenses/>.

   *
   * Authors:

   *   Haiyang Zhang <haiyangz@microsoft.com>

   *   Hank Janssen  <hjanssen@microsoft.com>

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/init.h>

  #include <linux/atomic.h>

  #include <linux/module.h>
  #include <linux/highmem.h>
  #include <linux/device.h>

  #include <linux/io.h>

  #include <linux/delay.h>
  #include <linux/netdevice.h>
  #include <linux/inetdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/skbuff.h>

  #include <linux/if_vlan.h>

  #include <linux/in.h>

  #include <linux/slab.h>

  #include <net/arp.h>
  #include <net/route.h>
  #include <net/sock.h>
  #include <net/pkt_sched.h>

  #include "hyperv_net.h"

  #define RING_SIZE_MIN 64

  #define LINKCHANGE_INT (2 * HZ)

  #define NETVSC_HW_FEATURES	(NETIF_F_RXCSUM | \
  				 NETIF_F_SG | \
  				 NETIF_F_TSO | \
  				 NETIF_F_TSO6 | \
  				 NETIF_F_HW_CSUM)

  
  /* Restrict GSO size to account for NVGRE */
  #define NETVSC_GSO_MAX_SIZE	62768

  static int ring_size = 128;

  module_param(ring_size, int, S_IRUGO);
  MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");

  static int max_num_vrss_chns = 8;

  static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
  				NETIF_MSG_LINK | NETIF_MSG_IFUP |
  				NETIF_MSG_IFDOWN | NETIF_MSG_RX_ERR |
  				NETIF_MSG_TX_ERR;
  
  static int debug = -1;
  module_param(debug, int, S_IRUGO);
  MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");

  static void do_set_multicast(struct work_struct *w)
  {

  	struct net_device_context *ndevctx =
  		container_of(w, struct net_device_context, work);

  	struct hv_device *device_obj = ndevctx->device_ctx;
  	struct net_device *ndev = hv_get_drvdata(device_obj);
  	struct netvsc_device *nvdev = ndevctx->nvdev;

  	struct rndis_device *rdev;

  	if (!nvdev)

  		return;

  
  	rdev = nvdev->extension;
  	if (rdev == NULL)

  		return;

  	if (ndev->flags & IFF_PROMISC)

  		rndis_filter_set_packet_filter(rdev,
  			NDIS_PACKET_TYPE_PROMISCUOUS);
  	else
  		rndis_filter_set_packet_filter(rdev,
  			NDIS_PACKET_TYPE_BROADCAST |
  			NDIS_PACKET_TYPE_ALL_MULTICAST |
  			NDIS_PACKET_TYPE_DIRECTED);

  }

  static void netvsc_set_multicast_list(struct net_device *net)

  {

  	struct net_device_context *net_device_ctx = netdev_priv(net);

  	schedule_work(&net_device_ctx->work);

  }

  static int netvsc_open(struct net_device *net)
  {

  	struct netvsc_device *nvdev = net_device_to_netvsc_device(net);

  	struct rndis_device *rdev;

  	int ret = 0;

  	netif_carrier_off(net);

  	/* Open up the device */

  	ret = rndis_filter_open(nvdev);

  	if (ret != 0) {
  		netdev_err(net, "unable to open device (ret %d).
  ", ret);
  		return ret;

  	}

  	netif_tx_wake_all_queues(net);

  	rdev = nvdev->extension;
  	if (!rdev->link_state)
  		netif_carrier_on(net);

  	return ret;
  }

  static int netvsc_close(struct net_device *net)
  {

  	struct net_device_context *net_device_ctx = netdev_priv(net);

  	struct netvsc_device *nvdev = net_device_ctx->nvdev;

  	int ret;

  	u32 aread, awrite, i, msec = 10, retry = 0, retry_max = 20;
  	struct vmbus_channel *chn;

  	netif_tx_disable(net);

  	/* Make sure netvsc_set_multicast_list doesn't re-enable filter! */
  	cancel_work_sync(&net_device_ctx->work);

  	ret = rndis_filter_close(nvdev);

  	if (ret != 0) {

  		netdev_err(net, "unable to close device (ret %d).
  ", ret);

  		return ret;
  	}
  
  	/* Ensure pending bytes in ring are read */
  	while (true) {
  		aread = 0;
  		for (i = 0; i < nvdev->num_chn; i++) {
  			chn = nvdev->chn_table[i];
  			if (!chn)
  				continue;
  
  			hv_get_ringbuffer_availbytes(&chn->inbound, &aread,
  						     &awrite);
  
  			if (aread)
  				break;
  
  			hv_get_ringbuffer_availbytes(&chn->outbound, &aread,
  						     &awrite);
  
  			if (aread)
  				break;
  		}
  
  		retry++;
  		if (retry > retry_max || aread == 0)
  			break;
  
  		msleep(msec);
  
  		if (msec < 1000)
  			msec *= 2;
  	}
  
  	if (aread) {
  		netdev_err(net, "Ring buffer not empty after closing rndis
  ");
  		ret = -ETIMEDOUT;
  	}

  	return ret;
  }

  static void *init_ppi_data(struct rndis_message *msg, u32 ppi_size,
  				int pkt_type)
  {
  	struct rndis_packet *rndis_pkt;
  	struct rndis_per_packet_info *ppi;
  
  	rndis_pkt = &msg->msg.pkt;
  	rndis_pkt->data_offset += ppi_size;
  
  	ppi = (struct rndis_per_packet_info *)((void *)rndis_pkt +
  		rndis_pkt->per_pkt_info_offset + rndis_pkt->per_pkt_info_len);
  
  	ppi->size = ppi_size;
  	ppi->type = pkt_type;
  	ppi->ppi_offset = sizeof(struct rndis_per_packet_info);
  
  	rndis_pkt->per_pkt_info_len += ppi_size;
  
  	return ppi;
  }

  static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
  			void *accel_priv, select_queue_fallback_t fallback)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(ndev);

  	struct netvsc_device *nvsc_dev = net_device_ctx->nvdev;

  	u32 hash;
  	u16 q_idx = 0;
  
  	if (nvsc_dev == NULL || ndev->real_num_tx_queues <= 1)
  		return 0;

  	hash = skb_get_hash(skb);
  	q_idx = nvsc_dev->send_table[hash % VRSS_SEND_TAB_SIZE] %
  		ndev->real_num_tx_queues;

  	if (!nvsc_dev->chn_table[q_idx])
  		q_idx = 0;

  	return q_idx;
  }

  static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
  			struct hv_page_buffer *pb)
  {
  	int j = 0;
  
  	/* Deal with compund pages by ignoring unused part
  	 * of the page.
  	 */
  	page += (offset >> PAGE_SHIFT);
  	offset &= ~PAGE_MASK;
  
  	while (len > 0) {
  		unsigned long bytes;
  
  		bytes = PAGE_SIZE - offset;
  		if (bytes > len)
  			bytes = len;
  		pb[j].pfn = page_to_pfn(page);
  		pb[j].offset = offset;
  		pb[j].len = bytes;
  
  		offset += bytes;
  		len -= bytes;
  
  		if (offset == PAGE_SIZE && len) {
  			page++;
  			offset = 0;
  			j++;
  		}
  	}
  
  	return j + 1;
  }

  static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,

  			   struct hv_netvsc_packet *packet,
  			   struct hv_page_buffer **page_buf)

  {

  	struct hv_page_buffer *pb = *page_buf;

  	u32 slots_used = 0;
  	char *data = skb->data;
  	int frags = skb_shinfo(skb)->nr_frags;
  	int i;
  
  	/* The packet is laid out thus:

  	 * 1. hdr: RNDIS header and PPI

  	 * 2. skb linear data
  	 * 3. skb fragment data
  	 */
  	if (hdr != NULL)
  		slots_used += fill_pg_buf(virt_to_page(hdr),
  					offset_in_page(hdr),
  					len, &pb[slots_used]);

  	packet->rmsg_size = len;
  	packet->rmsg_pgcnt = slots_used;

  	slots_used += fill_pg_buf(virt_to_page(data),
  				offset_in_page(data),
  				skb_headlen(skb), &pb[slots_used]);
  
  	for (i = 0; i < frags; i++) {
  		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
  
  		slots_used += fill_pg_buf(skb_frag_page(frag),
  					frag->page_offset,
  					skb_frag_size(frag), &pb[slots_used]);
  	}

  	return slots_used;

  }
  
  static int count_skb_frag_slots(struct sk_buff *skb)
  {
  	int i, frags = skb_shinfo(skb)->nr_frags;
  	int pages = 0;
  
  	for (i = 0; i < frags; i++) {
  		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
  		unsigned long size = skb_frag_size(frag);
  		unsigned long offset = frag->page_offset;
  
  		/* Skip unused frames from start of page */
  		offset &= ~PAGE_MASK;
  		pages += PFN_UP(offset + size);
  	}
  	return pages;
  }
  
  static int netvsc_get_slots(struct sk_buff *skb)
  {
  	char *data = skb->data;
  	unsigned int offset = offset_in_page(data);
  	unsigned int len = skb_headlen(skb);
  	int slots;
  	int frag_slots;
  
  	slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
  	frag_slots = count_skb_frag_slots(skb);
  	return slots + frag_slots;
  }

  static u32 get_net_transport_info(struct sk_buff *skb, u32 *trans_off)
  {
  	u32 ret_val = TRANSPORT_INFO_NOT_IP;
  
  	if ((eth_hdr(skb)->h_proto != htons(ETH_P_IP)) &&
  		(eth_hdr(skb)->h_proto != htons(ETH_P_IPV6))) {
  		goto not_ip;
  	}
  
  	*trans_off = skb_transport_offset(skb);
  
  	if ((eth_hdr(skb)->h_proto == htons(ETH_P_IP))) {
  		struct iphdr *iphdr = ip_hdr(skb);
  
  		if (iphdr->protocol == IPPROTO_TCP)
  			ret_val = TRANSPORT_INFO_IPV4_TCP;
  		else if (iphdr->protocol == IPPROTO_UDP)
  			ret_val = TRANSPORT_INFO_IPV4_UDP;
  	} else {
  		if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
  			ret_val = TRANSPORT_INFO_IPV6_TCP;
  		else if (ipv6_hdr(skb)->nexthdr == IPPROTO_UDP)
  			ret_val = TRANSPORT_INFO_IPV6_UDP;
  	}
  
  not_ip:
  	return ret_val;
  }

  static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)

  {

  	struct net_device_context *net_device_ctx = netdev_priv(net);

  	struct hv_netvsc_packet *packet = NULL;

  	int ret;

  	unsigned int num_data_pgs;
  	struct rndis_message *rndis_msg;
  	struct rndis_packet *rndis_pkt;
  	u32 rndis_msg_size;

  	struct rndis_per_packet_info *ppi;

  	struct ndis_tcp_ip_checksum_info *csum_info;
  	int  hdr_offset;
  	u32 net_trans_info;

  	u32 hash;

  	u32 skb_length;

  	struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];

  	struct hv_page_buffer *pb = page_buf;

  	/* We will atmost need two pages to describe the rndis
  	 * header. We can only transmit MAX_PAGE_BUFFER_COUNT number

  	 * of pages in a single packet. If skb is scattered around
  	 * more pages we try linearizing it.

  	 */

  	skb_length = skb->len;

  	num_data_pgs = netvsc_get_slots(skb) + 2;

  
  	if (unlikely(num_data_pgs > MAX_PAGE_BUFFER_COUNT)) {

  		++net_device_ctx->eth_stats.tx_scattered;
  
  		if (skb_linearize(skb))
  			goto no_memory;

  
  		num_data_pgs = netvsc_get_slots(skb) + 2;
  		if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {

  			++net_device_ctx->eth_stats.tx_too_big;

  			goto drop;
  		}

  	}

  	/*
  	 * Place the rndis header in the skb head room and
  	 * the skb->cb will be used for hv_netvsc_packet
  	 * structure.
  	 */
  	ret = skb_cow_head(skb, RNDIS_AND_PPI_SIZE);

  	if (ret)
  		goto no_memory;

  	/* Use the skb control buffer for building up the packet */
  	BUILD_BUG_ON(sizeof(struct hv_netvsc_packet) >
  			FIELD_SIZEOF(struct sk_buff, cb));
  	packet = (struct hv_netvsc_packet *)skb->cb;

  	packet->q_idx = skb_get_queue_mapping(skb);

  	packet->total_data_buflen = skb->len;

  	rndis_msg = (struct rndis_message *)skb->head;

  	memset(rndis_msg, 0, RNDIS_AND_PPI_SIZE);

  	/* Add the rndis header */

  	rndis_msg->ndis_msg_type = RNDIS_MSG_PACKET;
  	rndis_msg->msg_len = packet->total_data_buflen;
  	rndis_pkt = &rndis_msg->msg.pkt;
  	rndis_pkt->data_offset = sizeof(struct rndis_packet);
  	rndis_pkt->data_len = packet->total_data_buflen;
  	rndis_pkt->per_pkt_info_offset = sizeof(struct rndis_packet);
  
  	rndis_msg_size = RNDIS_MESSAGE_SIZE(struct rndis_packet);

  	hash = skb_get_hash_raw(skb);
  	if (hash != 0 && net->real_num_tx_queues > 1) {
  		rndis_msg_size += NDIS_HASH_PPI_SIZE;
  		ppi = init_ppi_data(rndis_msg, NDIS_HASH_PPI_SIZE,
  				    NBL_HASH_VALUE);
  		*(u32 *)((void *)ppi + ppi->ppi_offset) = hash;
  	}

  	if (skb_vlan_tag_present(skb)) {

  		struct ndis_pkt_8021q_info *vlan;
  
  		rndis_msg_size += NDIS_VLAN_PPI_SIZE;
  		ppi = init_ppi_data(rndis_msg, NDIS_VLAN_PPI_SIZE,
  					IEEE_8021Q_INFO);
  		vlan = (struct ndis_pkt_8021q_info *)((void *)ppi +
  						ppi->ppi_offset);

  		vlan->vlanid = skb->vlan_tci & VLAN_VID_MASK;
  		vlan->pri = (skb->vlan_tci & VLAN_PRIO_MASK) >>

  				VLAN_PRIO_SHIFT;
  	}

  	net_trans_info = get_net_transport_info(skb, &hdr_offset);

  
  	/*
  	 * Setup the sendside checksum offload only if this is not a
  	 * GSO packet.
  	 */

  	if ((net_trans_info & (INFO_TCP | INFO_UDP)) && skb_is_gso(skb)) {

  		struct ndis_tcp_lso_info *lso_info;
  
  		rndis_msg_size += NDIS_LSO_PPI_SIZE;
  		ppi = init_ppi_data(rndis_msg, NDIS_LSO_PPI_SIZE,
  				    TCP_LARGESEND_PKTINFO);
  
  		lso_info = (struct ndis_tcp_lso_info *)((void *)ppi +
  							ppi->ppi_offset);
  
  		lso_info->lso_v2_transmit.type = NDIS_TCP_LARGE_SEND_OFFLOAD_V2_TYPE;
  		if (net_trans_info & (INFO_IPV4 << 16)) {
  			lso_info->lso_v2_transmit.ip_version =
  				NDIS_TCP_LARGE_SEND_OFFLOAD_IPV4;
  			ip_hdr(skb)->tot_len = 0;
  			ip_hdr(skb)->check = 0;
  			tcp_hdr(skb)->check =
  				~csum_tcpudp_magic(ip_hdr(skb)->saddr,
  						   ip_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
  		} else {
  			lso_info->lso_v2_transmit.ip_version =
  				NDIS_TCP_LARGE_SEND_OFFLOAD_IPV6;
  			ipv6_hdr(skb)->payload_len = 0;
  			tcp_hdr(skb)->check =
  				~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
  						 &ipv6_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
  		}
  		lso_info->lso_v2_transmit.tcp_header_offset = hdr_offset;
  		lso_info->lso_v2_transmit.mss = skb_shinfo(skb)->gso_size;

  	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
  		if (net_trans_info & INFO_TCP) {
  			rndis_msg_size += NDIS_CSUM_PPI_SIZE;
  			ppi = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
  					    TCPIP_CHKSUM_PKTINFO);
  
  			csum_info = (struct ndis_tcp_ip_checksum_info *)((void *)ppi +
  									 ppi->ppi_offset);
  
  			if (net_trans_info & (INFO_IPV4 << 16))
  				csum_info->transmit.is_ipv4 = 1;
  			else
  				csum_info->transmit.is_ipv6 = 1;
  
  			csum_info->transmit.tcp_checksum = 1;
  			csum_info->transmit.tcp_header_offset = hdr_offset;
  		} else {
  			/* UDP checksum (and other) offload is not supported. */
  			if (skb_checksum_help(skb))
  				goto drop;
  		}

  	}

  	/* Start filling in the page buffers with the rndis hdr */
  	rndis_msg->msg_len += rndis_msg_size;

  	packet->total_data_buflen = rndis_msg->msg_len;

  	packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size,

  					       skb, packet, &pb);

  	/* timestamp packet in software */
  	skb_tx_timestamp(skb);

  	ret = netvsc_send(net_device_ctx->device_ctx, packet,
  			  rndis_msg, &pb, skb);

  	if (likely(ret == 0)) {

  		struct netvsc_stats *tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);

  		u64_stats_update_begin(&tx_stats->syncp);

  		tx_stats->packets++;
  		tx_stats->bytes += skb_length;

  		u64_stats_update_end(&tx_stats->syncp);

  		return NETDEV_TX_OK;

  	}

  
  	if (ret == -EAGAIN) {
  		++net_device_ctx->eth_stats.tx_busy;

  		return NETDEV_TX_BUSY;

  	}
  
  	if (ret == -ENOSPC)
  		++net_device_ctx->eth_stats.tx_no_space;

  
  drop:
  	dev_kfree_skb_any(skb);
  	net->stats.tx_dropped++;

  	return NETDEV_TX_OK;

  
  no_memory:
  	++net_device_ctx->eth_stats.tx_no_memory;
  	goto drop;

  }

  /*

   * netvsc_linkstatus_callback - Link up/down notification
   */

  void netvsc_linkstatus_callback(struct hv_device *device_obj,

  				struct rndis_message *resp)

  {

  	struct rndis_indicate_status *indicate = &resp->msg.indicate_status;

  	struct net_device *net;

  	struct net_device_context *ndev_ctx;

  	struct netvsc_reconfig *event;
  	unsigned long flags;

  	net = hv_get_drvdata(device_obj);
  
  	if (!net)
  		return;
  
  	ndev_ctx = netdev_priv(net);
  
  	/* Update the physical link speed when changing to another vSwitch */
  	if (indicate->status == RNDIS_STATUS_LINK_SPEED_CHANGE) {
  		u32 speed;
  
  		speed = *(u32 *)((void *)indicate + indicate->
  				 status_buf_offset) / 10000;
  		ndev_ctx->speed = speed;
  		return;
  	}
  
  	/* Handle these link change statuses below */

  	if (indicate->status != RNDIS_STATUS_NETWORK_CHANGE &&
  	    indicate->status != RNDIS_STATUS_MEDIA_CONNECT &&
  	    indicate->status != RNDIS_STATUS_MEDIA_DISCONNECT)

  		return;

  	if (net->reg_state != NETREG_REGISTERED)

  		return;

  	event = kzalloc(sizeof(*event), GFP_ATOMIC);
  	if (!event)
  		return;
  	event->event = indicate->status;
  
  	spin_lock_irqsave(&ndev_ctx->lock, flags);
  	list_add_tail(&event->list, &ndev_ctx->reconfig_events);
  	spin_unlock_irqrestore(&ndev_ctx->lock, flags);
  
  	schedule_delayed_work(&ndev_ctx->dwork, 0);

  }

  static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,

  				struct hv_netvsc_packet *packet,

  				struct ndis_tcp_ip_checksum_info *csum_info,

  				void *data, u16 vlan_tci)

  {

  	struct sk_buff *skb;

  	skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);

  	if (!skb)
  		return skb;

  	/*
  	 * Copy to skb. This copy is needed here since the memory pointed by
  	 * hv_netvsc_packet cannot be deallocated
  	 */

  	memcpy(skb_put(skb, packet->total_data_buflen), data,
  	       packet->total_data_buflen);

  
  	skb->protocol = eth_type_trans(skb, net);

  
  	/* skb is already created with CHECKSUM_NONE */
  	skb_checksum_none_assert(skb);
  
  	/*
  	 * In Linux, the IP checksum is always checked.
  	 * Do L4 checksum offload if enabled and present.
  	 */
  	if (csum_info && (net->features & NETIF_F_RXCSUM)) {
  		if (csum_info->receive.tcp_checksum_succeeded ||
  		    csum_info->receive.udp_checksum_succeeded)

  			skb->ip_summed = CHECKSUM_UNNECESSARY;

  	}

  	if (vlan_tci & VLAN_TAG_PRESENT)

  		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),

  				       vlan_tci);

  	return skb;
  }
  
  /*
   * netvsc_recv_callback -  Callback when we receive a packet from the
   * "wire" on the specified device.
   */
  int netvsc_recv_callback(struct hv_device *device_obj,
  				struct hv_netvsc_packet *packet,
  				void **data,
  				struct ndis_tcp_ip_checksum_info *csum_info,
  				struct vmbus_channel *channel,
  				u16 vlan_tci)
  {

  	struct net_device *net = hv_get_drvdata(device_obj);
  	struct net_device_context *net_device_ctx = netdev_priv(net);

  	struct net_device *vf_netdev;

  	struct sk_buff *skb;

  	struct netvsc_stats *rx_stats;

  	if (net->reg_state != NETREG_REGISTERED)

  		return NVSP_STAT_FAIL;

  	/*
  	 * If necessary, inject this packet into the VF interface.
  	 * On Hyper-V, multicast and brodcast packets are only delivered
  	 * to the synthetic interface (after subjecting these to
  	 * policy filters on the host). Deliver these via the VF
  	 * interface in the guest.
  	 */

  	rcu_read_lock();

  	vf_netdev = rcu_dereference(net_device_ctx->vf_netdev);

  	if (vf_netdev && (vf_netdev->flags & IFF_UP))
  		net = vf_netdev;

  
  	/* Allocate a skb - TODO direct I/O to pages? */
  	skb = netvsc_alloc_recv_skb(net, packet, csum_info, *data, vlan_tci);
  	if (unlikely(!skb)) {
  		++net->stats.rx_dropped;

  		rcu_read_unlock();

  		return NVSP_STAT_FAIL;
  	}

  	if (net != vf_netdev)
  		skb_record_rx_queue(skb,
  				    channel->offermsg.offer.sub_channel_index);
  
  	/*
  	 * Even if injecting the packet, record the statistics
  	 * on the synthetic device because modifying the VF device
  	 * statistics will not work correctly.
  	 */
  	rx_stats = this_cpu_ptr(net_device_ctx->rx_stats);

  	u64_stats_update_begin(&rx_stats->syncp);

  	rx_stats->packets++;
  	rx_stats->bytes += packet->total_data_buflen;

  
  	if (skb->pkt_type == PACKET_BROADCAST)
  		++rx_stats->broadcast;
  	else if (skb->pkt_type == PACKET_MULTICAST)
  		++rx_stats->multicast;

  	u64_stats_update_end(&rx_stats->syncp);

  	/*
  	 * Pass the skb back up. Network stack will deallocate the skb when it

  	 * is done.
  	 * TODO - use NAPI?

  	 */

  	netif_rx(skb);

  	rcu_read_unlock();

  	return 0;
  }

  static void netvsc_get_drvinfo(struct net_device *net,
  			       struct ethtool_drvinfo *info)
  {

  	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));

  	strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));

  }

  static void netvsc_get_channels(struct net_device *net,
  				struct ethtool_channels *channel)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(net);

  	struct netvsc_device *nvdev = net_device_ctx->nvdev;

  
  	if (nvdev) {
  		channel->max_combined	= nvdev->max_chn;
  		channel->combined_count = nvdev->num_chn;
  	}
  }

  static int netvsc_set_channels(struct net_device *net,
  			       struct ethtool_channels *channels)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(net);
  	struct hv_device *dev = net_device_ctx->device_ctx;

  	struct netvsc_device *nvdev = net_device_ctx->nvdev;

  	struct netvsc_device_info device_info;

  	u32 num_chn;
  	u32 max_chn;

  	int ret = 0;
  	bool recovering = false;

  	if (net_device_ctx->start_remove || !nvdev || nvdev->destroy)

  		return -ENODEV;

  	num_chn = nvdev->num_chn;
  	max_chn = min_t(u32, nvdev->max_chn, num_online_cpus());

  	if (nvdev->nvsp_version < NVSP_PROTOCOL_VERSION_5) {
  		pr_info("vRSS unsupported before NVSP Version 5
  ");
  		return -EINVAL;
  	}
  
  	/* We do not support rx, tx, or other */
  	if (!channels ||
  	    channels->rx_count ||
  	    channels->tx_count ||
  	    channels->other_count ||
  	    (channels->combined_count < 1))
  		return -EINVAL;
  
  	if (channels->combined_count > max_chn) {
  		pr_info("combined channels too high, using %d
  ", max_chn);
  		channels->combined_count = max_chn;
  	}
  
  	ret = netvsc_close(net);
  	if (ret)
  		goto out;
  
   do_set:

  	net_device_ctx->start_remove = true;

  	rndis_filter_device_remove(dev);
  
  	nvdev->num_chn = channels->combined_count;

  	memset(&device_info, 0, sizeof(device_info));
  	device_info.num_chn = nvdev->num_chn; /* passed to RNDIS */
  	device_info.ring_size = ring_size;
  	device_info.max_num_vrss_chns = max_num_vrss_chns;
  
  	ret = rndis_filter_device_add(dev, &device_info);
  	if (ret) {
  		if (recovering) {
  			netdev_err(net, "unable to add netvsc device (ret %d)
  ", ret);
  			return ret;
  		}
  		goto recover;
  	}

  	nvdev = net_device_ctx->nvdev;

  
  	ret = netif_set_real_num_tx_queues(net, nvdev->num_chn);
  	if (ret) {
  		if (recovering) {
  			netdev_err(net, "could not set tx queue count (ret %d)
  ", ret);
  			return ret;
  		}
  		goto recover;
  	}
  
  	ret = netif_set_real_num_rx_queues(net, nvdev->num_chn);
  	if (ret) {
  		if (recovering) {
  			netdev_err(net, "could not set rx queue count (ret %d)
  ", ret);
  			return ret;
  		}
  		goto recover;
  	}
  
   out:
  	netvsc_open(net);

  	net_device_ctx->start_remove = false;

  	/* We may have missed link change notifications */
  	schedule_delayed_work(&net_device_ctx->dwork, 0);

  
  	return ret;
  
   recover:
  	/* If the above failed, we attempt to recover through the same
  	 * process but with the original number of channels.
  	 */
  	netdev_err(net, "could not set channels, recovering
  ");
  	recovering = true;
  	channels->combined_count = num_chn;
  	goto do_set;
  }

  static bool netvsc_validate_ethtool_ss_cmd(const struct ethtool_cmd *cmd)
  {
  	struct ethtool_cmd diff1 = *cmd;
  	struct ethtool_cmd diff2 = {};
  
  	ethtool_cmd_speed_set(&diff1, 0);
  	diff1.duplex = 0;
  	/* advertising and cmd are usually set */
  	diff1.advertising = 0;
  	diff1.cmd = 0;
  	/* We set port to PORT_OTHER */
  	diff2.port = PORT_OTHER;
  
  	return !memcmp(&diff1, &diff2, sizeof(diff1));
  }
  
  static void netvsc_init_settings(struct net_device *dev)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  
  	ndc->speed = SPEED_UNKNOWN;
  	ndc->duplex = DUPLEX_UNKNOWN;
  }
  
  static int netvsc_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  
  	ethtool_cmd_speed_set(cmd, ndc->speed);
  	cmd->duplex = ndc->duplex;
  	cmd->port = PORT_OTHER;
  
  	return 0;
  }
  
  static int netvsc_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	u32 speed;
  
  	speed = ethtool_cmd_speed(cmd);
  	if (!ethtool_validate_speed(speed) ||
  	    !ethtool_validate_duplex(cmd->duplex) ||
  	    !netvsc_validate_ethtool_ss_cmd(cmd))
  		return -EINVAL;
  
  	ndc->speed = speed;
  	ndc->duplex = cmd->duplex;
  
  	return 0;
  }

  static int netvsc_change_mtu(struct net_device *ndev, int mtu)
  {
  	struct net_device_context *ndevctx = netdev_priv(ndev);

  	struct netvsc_device *nvdev = ndevctx->nvdev;
  	struct hv_device *hdev = ndevctx->device_ctx;

  	struct netvsc_device_info device_info;
  	int limit = ETH_DATA_LEN;

  	u32 num_chn;

  	int ret = 0;

  	if (ndevctx->start_remove || !nvdev || nvdev->destroy)

  		return -ENODEV;

  	if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)

  		limit = NETVSC_MTU - ETH_HLEN;

  	if (mtu < NETVSC_MTU_MIN || mtu > limit)

  		return -EINVAL;

  	ret = netvsc_close(ndev);
  	if (ret)
  		goto out;

  	num_chn = nvdev->num_chn;

  	ndevctx->start_remove = true;

  	rndis_filter_device_remove(hdev);
  
  	ndev->mtu = mtu;

  	memset(&device_info, 0, sizeof(device_info));

  	device_info.ring_size = ring_size;

  	device_info.num_chn = num_chn;

  	device_info.max_num_vrss_chns = max_num_vrss_chns;

  	rndis_filter_device_add(hdev, &device_info);

  out:
  	netvsc_open(ndev);

  	ndevctx->start_remove = false;

  	/* We may have missed link change notifications */
  	schedule_delayed_work(&ndevctx->dwork, 0);

  	return ret;

  }

  static struct rtnl_link_stats64 *netvsc_get_stats64(struct net_device *net,
  						    struct rtnl_link_stats64 *t)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	int cpu;
  
  	for_each_possible_cpu(cpu) {
  		struct netvsc_stats *tx_stats = per_cpu_ptr(ndev_ctx->tx_stats,
  							    cpu);
  		struct netvsc_stats *rx_stats = per_cpu_ptr(ndev_ctx->rx_stats,
  							    cpu);

  		u64 tx_packets, tx_bytes, rx_packets, rx_bytes, rx_multicast;

  		unsigned int start;
  
  		do {

  			start = u64_stats_fetch_begin_irq(&tx_stats->syncp);

  			tx_packets = tx_stats->packets;
  			tx_bytes = tx_stats->bytes;

  		} while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));

  
  		do {

  			start = u64_stats_fetch_begin_irq(&rx_stats->syncp);

  			rx_packets = rx_stats->packets;
  			rx_bytes = rx_stats->bytes;

  			rx_multicast = rx_stats->multicast + rx_stats->broadcast;

  		} while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));

  
  		t->tx_bytes	+= tx_bytes;
  		t->tx_packets	+= tx_packets;
  		t->rx_bytes	+= rx_bytes;
  		t->rx_packets	+= rx_packets;

  		t->multicast	+= rx_multicast;

  	}
  
  	t->tx_dropped	= net->stats.tx_dropped;
  	t->tx_errors	= net->stats.tx_dropped;
  
  	t->rx_dropped	= net->stats.rx_dropped;
  	t->rx_errors	= net->stats.rx_errors;
  
  	return t;
  }

  
  static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
  {

  	struct sockaddr *addr = p;

  	char save_adr[ETH_ALEN];

  	unsigned char save_aatype;
  	int err;
  
  	memcpy(save_adr, ndev->dev_addr, ETH_ALEN);
  	save_aatype = ndev->addr_assign_type;
  
  	err = eth_mac_addr(ndev, p);
  	if (err != 0)
  		return err;

  	err = rndis_filter_set_device_mac(ndev, addr->sa_data);

  	if (err != 0) {
  		/* roll back to saved MAC */
  		memcpy(ndev->dev_addr, save_adr, ETH_ALEN);
  		ndev->addr_assign_type = save_aatype;
  	}
  
  	return err;
  }

  static const struct {
  	char name[ETH_GSTRING_LEN];
  	u16 offset;
  } netvsc_stats[] = {
  	{ "tx_scattered", offsetof(struct netvsc_ethtool_stats, tx_scattered) },
  	{ "tx_no_memory",  offsetof(struct netvsc_ethtool_stats, tx_no_memory) },
  	{ "tx_no_space",  offsetof(struct netvsc_ethtool_stats, tx_no_space) },
  	{ "tx_too_big",	  offsetof(struct netvsc_ethtool_stats, tx_too_big) },
  	{ "tx_busy",	  offsetof(struct netvsc_ethtool_stats, tx_busy) },
  };
  
  static int netvsc_get_sset_count(struct net_device *dev, int string_set)
  {
  	switch (string_set) {
  	case ETH_SS_STATS:
  		return ARRAY_SIZE(netvsc_stats);
  	default:
  		return -EINVAL;
  	}
  }
  
  static void netvsc_get_ethtool_stats(struct net_device *dev,
  				     struct ethtool_stats *stats, u64 *data)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	const void *nds = &ndc->eth_stats;
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++)
  		data[i] = *(unsigned long *)(nds + netvsc_stats[i].offset);
  }
  
  static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)
  {
  	int i;
  
  	switch (stringset) {
  	case ETH_SS_STATS:
  		for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++)
  			memcpy(data + i * ETH_GSTRING_LEN,
  			       netvsc_stats[i].name, ETH_GSTRING_LEN);
  		break;
  	}
  }

  #ifdef CONFIG_NET_POLL_CONTROLLER
  static void netvsc_poll_controller(struct net_device *net)
  {
  	/* As netvsc_start_xmit() works synchronous we don't have to
  	 * trigger anything here.
  	 */
  }
  #endif

  static const struct ethtool_ops ethtool_ops = {
  	.get_drvinfo	= netvsc_get_drvinfo,

  	.get_link	= ethtool_op_get_link,

  	.get_ethtool_stats = netvsc_get_ethtool_stats,
  	.get_sset_count = netvsc_get_sset_count,
  	.get_strings	= netvsc_get_strings,

  	.get_channels   = netvsc_get_channels,

  	.set_channels   = netvsc_set_channels,

  	.get_ts_info	= ethtool_op_get_ts_info,

  	.get_settings	= netvsc_get_settings,
  	.set_settings	= netvsc_set_settings,

  };

  static const struct net_device_ops device_ops = {
  	.ndo_open =			netvsc_open,
  	.ndo_stop =			netvsc_close,
  	.ndo_start_xmit =		netvsc_start_xmit,

  	.ndo_set_rx_mode =		netvsc_set_multicast_list,

  	.ndo_change_mtu =		netvsc_change_mtu,

  	.ndo_validate_addr =		eth_validate_addr,

  	.ndo_set_mac_address =		netvsc_set_mac_addr,

  	.ndo_select_queue =		netvsc_select_queue,

  	.ndo_get_stats64 =		netvsc_get_stats64,

  #ifdef CONFIG_NET_POLL_CONTROLLER
  	.ndo_poll_controller =		netvsc_poll_controller,
  #endif

  };

  /*

   * Handle link status changes. For RNDIS_STATUS_NETWORK_CHANGE emulate link
   * down/up sequence. In case of RNDIS_STATUS_MEDIA_CONNECT when carrier is
   * present send GARP packet to network peers with netif_notify_peers().

   */

  static void netvsc_link_change(struct work_struct *w)

  {

  	struct net_device_context *ndev_ctx =
  		container_of(w, struct net_device_context, dwork.work);
  	struct hv_device *device_obj = ndev_ctx->device_ctx;
  	struct net_device *net = hv_get_drvdata(device_obj);

  	struct netvsc_device *net_device;

  	struct rndis_device *rdev;

  	struct netvsc_reconfig *event = NULL;
  	bool notify = false, reschedule = false;
  	unsigned long flags, next_reconfig, delay;

  	rtnl_lock();
  	if (ndev_ctx->start_remove)
  		goto out_unlock;

  	net_device = ndev_ctx->nvdev;

  	rdev = net_device->extension;

  	next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
  	if (time_is_after_jiffies(next_reconfig)) {
  		/* link_watch only sends one notification with current state
  		 * per second, avoid doing reconfig more frequently. Handle
  		 * wrap around.
  		 */
  		delay = next_reconfig - jiffies;
  		delay = delay < LINKCHANGE_INT ? delay : LINKCHANGE_INT;
  		schedule_delayed_work(&ndev_ctx->dwork, delay);

  		goto out_unlock;

  	}
  	ndev_ctx->last_reconfig = jiffies;
  
  	spin_lock_irqsave(&ndev_ctx->lock, flags);
  	if (!list_empty(&ndev_ctx->reconfig_events)) {
  		event = list_first_entry(&ndev_ctx->reconfig_events,
  					 struct netvsc_reconfig, list);
  		list_del(&event->list);
  		reschedule = !list_empty(&ndev_ctx->reconfig_events);
  	}
  	spin_unlock_irqrestore(&ndev_ctx->lock, flags);
  
  	if (!event)

  		goto out_unlock;

  
  	switch (event->event) {
  		/* Only the following events are possible due to the check in
  		 * netvsc_linkstatus_callback()
  		 */
  	case RNDIS_STATUS_MEDIA_CONNECT:
  		if (rdev->link_state) {
  			rdev->link_state = false;
  			netif_carrier_on(net);
  			netif_tx_wake_all_queues(net);
  		} else {
  			notify = true;
  		}
  		kfree(event);
  		break;
  	case RNDIS_STATUS_MEDIA_DISCONNECT:
  		if (!rdev->link_state) {
  			rdev->link_state = true;
  			netif_carrier_off(net);
  			netif_tx_stop_all_queues(net);
  		}
  		kfree(event);
  		break;
  	case RNDIS_STATUS_NETWORK_CHANGE:
  		/* Only makes sense if carrier is present */
  		if (!rdev->link_state) {
  			rdev->link_state = true;
  			netif_carrier_off(net);
  			netif_tx_stop_all_queues(net);
  			event->event = RNDIS_STATUS_MEDIA_CONNECT;
  			spin_lock_irqsave(&ndev_ctx->lock, flags);

  			list_add(&event->list, &ndev_ctx->reconfig_events);

  			spin_unlock_irqrestore(&ndev_ctx->lock, flags);
  			reschedule = true;

  		}

  		break;

  	}
  
  	rtnl_unlock();
  
  	if (notify)
  		netdev_notify_peers(net);

  
  	/* link_watch only sends one notification with current state per
  	 * second, handle next reconfig event in 2 seconds.
  	 */
  	if (reschedule)
  		schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT);

  
  	return;
  
  out_unlock:
  	rtnl_unlock();

  }

  static void netvsc_free_netdev(struct net_device *netdev)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(netdev);
  
  	free_percpu(net_device_ctx->tx_stats);
  	free_percpu(net_device_ctx->rx_stats);
  	free_netdev(netdev);
  }

  static struct net_device *get_netvsc_bymac(const u8 *mac)

  {

  	struct net_device *dev;

  	ASSERT_RTNL();

  
  	for_each_netdev(&init_net, dev) {

  		if (dev->netdev_ops != &device_ops)
  			continue;	/* not a netvsc device */
  
  		if (ether_addr_equal(mac, dev->perm_addr))
  			return dev;
  	}
  
  	return NULL;
  }

  static struct net_device *get_netvsc_byref(struct net_device *vf_netdev)

  {
  	struct net_device *dev;
  
  	ASSERT_RTNL();
  
  	for_each_netdev(&init_net, dev) {
  		struct net_device_context *net_device_ctx;
  
  		if (dev->netdev_ops != &device_ops)
  			continue;	/* not a netvsc device */
  
  		net_device_ctx = netdev_priv(dev);
  		if (net_device_ctx->nvdev == NULL)
  			continue;	/* device is removed */

  		if (rtnl_dereference(net_device_ctx->vf_netdev) == vf_netdev)

  			return dev;	/* a match */

  	}

  	return NULL;

  }
  
  static int netvsc_register_vf(struct net_device *vf_netdev)
  {

  	struct net_device *ndev;
  	struct net_device_context *net_device_ctx;

  	struct netvsc_device *netvsc_dev;

  	if (vf_netdev->addr_len != ETH_ALEN)
  		return NOTIFY_DONE;

  	/*
  	 * We will use the MAC address to locate the synthetic interface to
  	 * associate with the VF interface. If we don't find a matching
  	 * synthetic interface, move on.
  	 */

  	ndev = get_netvsc_bymac(vf_netdev->perm_addr);

  	if (!ndev)
  		return NOTIFY_DONE;
  
  	net_device_ctx = netdev_priv(ndev);
  	netvsc_dev = net_device_ctx->nvdev;

  	if (!netvsc_dev || rtnl_dereference(net_device_ctx->vf_netdev))

  		return NOTIFY_DONE;

  	netdev_info(ndev, "VF registering: %s
  ", vf_netdev->name);

  	/*
  	 * Take a reference on the module.
  	 */
  	try_module_get(THIS_MODULE);

  
  	dev_hold(vf_netdev);

  	rcu_assign_pointer(net_device_ctx->vf_netdev, vf_netdev);

  	return NOTIFY_OK;
  }

  static int netvsc_vf_up(struct net_device *vf_netdev)
  {

  	struct net_device *ndev;

  	struct netvsc_device *netvsc_dev;

  	struct net_device_context *net_device_ctx;

  	ndev = get_netvsc_byref(vf_netdev);

  	if (!ndev)
  		return NOTIFY_DONE;
  
  	net_device_ctx = netdev_priv(ndev);
  	netvsc_dev = net_device_ctx->nvdev;

  	netdev_info(ndev, "VF up: %s
  ", vf_netdev->name);

  
  	/*
  	 * Open the device before switching data path.
  	 */

  	rndis_filter_open(netvsc_dev);

  
  	/*
  	 * notify the host to switch the data path.
  	 */

  	netvsc_switch_datapath(ndev, true);
  	netdev_info(ndev, "Data path switched to VF: %s
  ", vf_netdev->name);

  	netif_carrier_off(ndev);

  	/* Now notify peers through VF device. */
  	call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, vf_netdev);

  
  	return NOTIFY_OK;
  }

  static int netvsc_vf_down(struct net_device *vf_netdev)
  {

  	struct net_device *ndev;

  	struct netvsc_device *netvsc_dev;
  	struct net_device_context *net_device_ctx;

  	ndev = get_netvsc_byref(vf_netdev);

  	if (!ndev)
  		return NOTIFY_DONE;
  
  	net_device_ctx = netdev_priv(ndev);
  	netvsc_dev = net_device_ctx->nvdev;

  	netdev_info(ndev, "VF down: %s
  ", vf_netdev->name);

  	netvsc_switch_datapath(ndev, false);
  	netdev_info(ndev, "Data path switched from VF: %s
  ", vf_netdev->name);

  	rndis_filter_close(netvsc_dev);

  	netif_carrier_on(ndev);

  
  	/* Now notify peers through netvsc device. */
  	call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, ndev);

  
  	return NOTIFY_OK;
  }

  static int netvsc_unregister_vf(struct net_device *vf_netdev)
  {

  	struct net_device *ndev;

  	struct netvsc_device *netvsc_dev;

  	struct net_device_context *net_device_ctx;

  	ndev = get_netvsc_byref(vf_netdev);

  	if (!ndev)
  		return NOTIFY_DONE;
  
  	net_device_ctx = netdev_priv(ndev);
  	netvsc_dev = net_device_ctx->nvdev;

  	netdev_info(ndev, "VF unregistering: %s
  ", vf_netdev->name);

  
  	RCU_INIT_POINTER(net_device_ctx->vf_netdev, NULL);

  	dev_put(vf_netdev);

  	module_put(THIS_MODULE);
  	return NOTIFY_OK;
  }

  static int netvsc_probe(struct hv_device *dev,
  			const struct hv_vmbus_device_id *dev_id)

  {

  	struct net_device *net = NULL;
  	struct net_device_context *net_device_ctx;
  	struct netvsc_device_info device_info;

  	struct netvsc_device *nvdev;

  	int ret;

  	net = alloc_etherdev_mq(sizeof(struct net_device_context),
  				num_online_cpus());

  	if (!net)

  		return -ENOMEM;

  	netif_carrier_off(net);

  	netvsc_init_settings(net);

  	net_device_ctx = netdev_priv(net);

  	net_device_ctx->device_ctx = dev;

  	net_device_ctx->msg_enable = netif_msg_init(debug, default_msg);
  	if (netif_msg_probe(net_device_ctx))
  		netdev_dbg(net, "netvsc msg_enable: %d
  ",
  			   net_device_ctx->msg_enable);

  	net_device_ctx->tx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
  	if (!net_device_ctx->tx_stats) {
  		free_netdev(net);
  		return -ENOMEM;
  	}
  	net_device_ctx->rx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
  	if (!net_device_ctx->rx_stats) {
  		free_percpu(net_device_ctx->tx_stats);
  		free_netdev(net);
  		return -ENOMEM;
  	}

  	hv_set_drvdata(dev, net);

  
  	net_device_ctx->start_remove = false;

  	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);

  	INIT_WORK(&net_device_ctx->work, do_set_multicast);

  	spin_lock_init(&net_device_ctx->lock);
  	INIT_LIST_HEAD(&net_device_ctx->reconfig_events);

  	net->netdev_ops = &device_ops;

  	net->hw_features = NETVSC_HW_FEATURES;
  	net->features = NETVSC_HW_FEATURES | NETIF_F_HW_VLAN_CTAG_TX;

  	net->ethtool_ops = &ethtool_ops;

  	SET_NETDEV_DEV(net, &dev->device);

  	/* We always need headroom for rndis header */
  	net->needed_headroom = RNDIS_AND_PPI_SIZE;

  	/* Notify the netvsc driver of the new device */

  	memset(&device_info, 0, sizeof(device_info));

  	device_info.ring_size = ring_size;

  	device_info.max_num_vrss_chns = max_num_vrss_chns;

  	ret = rndis_filter_device_add(dev, &device_info);
  	if (ret != 0) {
  		netdev_err(net, "unable to add netvsc device (ret %d)
  ", ret);

  		netvsc_free_netdev(net);

  		hv_set_drvdata(dev, NULL);

  		return ret;

  	}

  	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);

  	nvdev = net_device_ctx->nvdev;

  	netif_set_real_num_tx_queues(net, nvdev->num_chn);
  	netif_set_real_num_rx_queues(net, nvdev->num_chn);

  	netif_set_gso_max_size(net, NETVSC_GSO_MAX_SIZE);

  	ret = register_netdev(net);
  	if (ret != 0) {
  		pr_err("Unable to register netdev.
  ");
  		rndis_filter_device_remove(dev);

  		netvsc_free_netdev(net);

  	}

  	return ret;
  }

  static int netvsc_remove(struct hv_device *dev)

  {

  	struct net_device *net;

  	struct net_device_context *ndev_ctx;

  	struct netvsc_device *net_device;

  	net = hv_get_drvdata(dev);

  	if (net == NULL) {

  		dev_err(&dev->device, "No net device to remove
  ");

  		return 0;
  	}

  	ndev_ctx = netdev_priv(net);

  	net_device = ndev_ctx->nvdev;

  	/* Avoid racing with netvsc_change_mtu()/netvsc_set_channels()
  	 * removing the device.
  	 */
  	rtnl_lock();

  	ndev_ctx->start_remove = true;

  	rtnl_unlock();

  	cancel_delayed_work_sync(&ndev_ctx->dwork);

  	cancel_work_sync(&ndev_ctx->work);

  	/* Stop outbound asap */

  	netif_tx_disable(net);

  
  	unregister_netdev(net);
  
  	/*
  	 * Call to the vsc driver to let it know that the device is being
  	 * removed
  	 */

  	rndis_filter_device_remove(dev);

  	hv_set_drvdata(dev, NULL);

  	netvsc_free_netdev(net);

  	return 0;

  }

  static const struct hv_vmbus_device_id id_table[] = {

  	/* Network guid */

  	{ HV_NIC_GUID, },

  	{ },

  };
  
  MODULE_DEVICE_TABLE(vmbus, id_table);

  /* The one and only one */

  static struct  hv_driver netvsc_drv = {

  	.name = KBUILD_MODNAME,

  	.id_table = id_table,

  	.probe = netvsc_probe,
  	.remove = netvsc_remove,

  };

  /*
   * On Hyper-V, every VF interface is matched with a corresponding
   * synthetic interface. The synthetic interface is presented first
   * to the guest. When the corresponding VF instance is registered,
   * we will take care of switching the data path.
   */
  static int netvsc_netdev_event(struct notifier_block *this,
  			       unsigned long event, void *ptr)
  {
  	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);

  	/* Skip our own events */
  	if (event_dev->netdev_ops == &device_ops)
  		return NOTIFY_DONE;
  
  	/* Avoid non-Ethernet type devices */
  	if (event_dev->type != ARPHRD_ETHER)
  		return NOTIFY_DONE;

  	/* Avoid Vlan dev with same MAC registering as VF */
  	if (event_dev->priv_flags & IFF_802_1Q_VLAN)
  		return NOTIFY_DONE;
  
  	/* Avoid Bonding master dev with same MAC registering as VF */

  	if ((event_dev->priv_flags & IFF_BONDING) &&
  	    (event_dev->flags & IFF_MASTER))

  		return NOTIFY_DONE;

  	switch (event) {
  	case NETDEV_REGISTER:
  		return netvsc_register_vf(event_dev);
  	case NETDEV_UNREGISTER:
  		return netvsc_unregister_vf(event_dev);
  	case NETDEV_UP:
  		return netvsc_vf_up(event_dev);
  	case NETDEV_DOWN:
  		return netvsc_vf_down(event_dev);
  	default:
  		return NOTIFY_DONE;
  	}
  }
  
  static struct notifier_block netvsc_netdev_notifier = {
  	.notifier_call = netvsc_netdev_event,
  };

  static void __exit netvsc_drv_exit(void)

  {

  	unregister_netdevice_notifier(&netvsc_netdev_notifier);

  	vmbus_driver_unregister(&netvsc_drv);

  }

  static int __init netvsc_drv_init(void)

  {

  	int ret;

  	if (ring_size < RING_SIZE_MIN) {
  		ring_size = RING_SIZE_MIN;
  		pr_info("Increased ring_size to %d (min allowed)
  ",
  			ring_size);
  	}

  	ret = vmbus_driver_register(&netvsc_drv);
  
  	if (ret)
  		return ret;
  
  	register_netdevice_notifier(&netvsc_netdev_notifier);
  	return 0;

  }

  MODULE_LICENSE("GPL");

  MODULE_DESCRIPTION("Microsoft Hyper-V network driver");

  module_init(netvsc_drv_init);

  module_exit(netvsc_drv_exit);