Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / net / hyperv / netvsc_drv.c
diff --git a/kernel/drivers/net/hyperv/netvsc_drv.c b/kernel/drivers/net/hyperv/netvsc_drv.c
new file mode 100644 (file)
index 0000000..5993c7e
--- /dev/null
@@ -0,0 +1,1004 @@
+/*
+ * 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
+static int ring_size = 128;
+module_param(ring_size, int, S_IRUGO);
+MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
+
+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 netvsc_device *nvdev;
+       struct rndis_device *rdev;
+
+       nvdev = hv_get_drvdata(ndevctx->device_ctx);
+       if (nvdev == NULL || nvdev->ndev == NULL)
+               return;
+
+       rdev = nvdev->extension;
+       if (rdev == NULL)
+               return;
+
+       if (nvdev->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 net_device_context *net_device_ctx = netdev_priv(net);
+       struct hv_device *device_obj = net_device_ctx->device_ctx;
+       struct netvsc_device *nvdev;
+       struct rndis_device *rdev;
+       int ret = 0;
+
+       netif_carrier_off(net);
+
+       /* Open up the device */
+       ret = rndis_filter_open(device_obj);
+       if (ret != 0) {
+               netdev_err(net, "unable to open device (ret %d).\n", ret);
+               return ret;
+       }
+
+       netif_tx_start_all_queues(net);
+
+       nvdev = hv_get_drvdata(device_obj);
+       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 hv_device *device_obj = net_device_ctx->device_ctx;
+       int ret;
+
+       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(device_obj);
+       if (ret != 0)
+               netdev_err(net, "unable to close device (ret %d).\n", ret);
+
+       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;
+}
+
+union sub_key {
+       u64 k;
+       struct {
+               u8 pad[3];
+               u8 kb;
+               u32 ka;
+       };
+};
+
+/* Toeplitz hash function
+ * data: network byte order
+ * return: host byte order
+ */
+static u32 comp_hash(u8 *key, int klen, void *data, int dlen)
+{
+       union sub_key subk;
+       int k_next = 4;
+       u8 dt;
+       int i, j;
+       u32 ret = 0;
+
+       subk.k = 0;
+       subk.ka = ntohl(*(u32 *)key);
+
+       for (i = 0; i < dlen; i++) {
+               subk.kb = key[k_next];
+               k_next = (k_next + 1) % klen;
+               dt = ((u8 *)data)[i];
+               for (j = 0; j < 8; j++) {
+                       if (dt & 0x80)
+                               ret ^= subk.ka;
+                       dt <<= 1;
+                       subk.k <<= 1;
+               }
+       }
+
+       return ret;
+}
+
+static bool netvsc_set_hash(u32 *hash, struct sk_buff *skb)
+{
+       struct flow_keys flow;
+       int data_len;
+
+       if (!skb_flow_dissect(skb, &flow) ||
+           !(flow.n_proto == htons(ETH_P_IP) ||
+             flow.n_proto == htons(ETH_P_IPV6)))
+               return false;
+
+       if (flow.ip_proto == IPPROTO_TCP)
+               data_len = 12;
+       else
+               data_len = 8;
+
+       *hash = comp_hash(netvsc_hash_key, HASH_KEYLEN, &flow, data_len);
+
+       return true;
+}
+
+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 hv_device *hdev =  net_device_ctx->device_ctx;
+       struct netvsc_device *nvsc_dev = hv_get_drvdata(hdev);
+       u32 hash;
+       u16 q_idx = 0;
+
+       if (nvsc_dev == NULL || ndev->real_num_tx_queues <= 1)
+               return 0;
+
+       if (netvsc_set_hash(&hash, skb)) {
+               q_idx = nvsc_dev->send_table[hash % VRSS_SEND_TAB_SIZE] %
+                       ndev->real_num_tx_queues;
+               skb_set_hash(skb, hash, PKT_HASH_TYPE_L3);
+       }
+
+       return q_idx;
+}
+
+void netvsc_xmit_completion(void *context)
+{
+       struct hv_netvsc_packet *packet = (struct hv_netvsc_packet *)context;
+       struct sk_buff *skb = (struct sk_buff *)
+               (unsigned long)packet->send_completion_tid;
+
+       if (skb)
+               dev_kfree_skb_any(skb);
+}
+
+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 *pb = packet->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;
+       bool isvlan;
+       bool linear = false;
+       struct rndis_per_packet_info *ppi;
+       struct ndis_tcp_ip_checksum_info *csum_info;
+       struct ndis_tcp_lso_info *lso_info;
+       int  hdr_offset;
+       u32 net_trans_info;
+       u32 hash;
+       u32 skb_length;
+       u32 pkt_sz;
+       struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
+
+
+       /* 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.
+        */
+
+check_size:
+       skb_length = skb->len;
+       num_data_pgs = netvsc_get_slots(skb) + 2;
+       if (num_data_pgs > MAX_PAGE_BUFFER_COUNT && linear) {
+               net_alert_ratelimited("packet too big: %u pages (%u bytes)\n",
+                                     num_data_pgs, skb->len);
+               ret = -EFAULT;
+               goto drop;
+       } else if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
+               if (skb_linearize(skb)) {
+                       net_alert_ratelimited("failed to linearize skb\n");
+                       ret = -ENOMEM;
+                       goto drop;
+               }
+               linear = true;
+               goto check_size;
+       }
+
+       pkt_sz = sizeof(struct hv_netvsc_packet) + RNDIS_AND_PPI_SIZE;
+
+       ret = skb_cow_head(skb, pkt_sz);
+       if (ret) {
+               netdev_err(net, "unable to alloc hv_netvsc_packet\n");
+               ret = -ENOMEM;
+               goto drop;
+       }
+       /* Use the headroom for building up the packet */
+       packet = (struct hv_netvsc_packet *)skb->head;
+
+       packet->status = 0;
+       packet->xmit_more = skb->xmit_more;
+
+       packet->vlan_tci = skb->vlan_tci;
+       packet->page_buf = page_buf;
+
+       packet->q_idx = skb_get_queue_mapping(skb);
+
+       packet->is_data_pkt = true;
+       packet->total_data_buflen = skb->len;
+
+       packet->rndis_msg = (struct rndis_message *)((unsigned long)packet +
+                               sizeof(struct hv_netvsc_packet));
+
+       memset(packet->rndis_msg, 0, RNDIS_AND_PPI_SIZE);
+
+       /* Set the completion routine */
+       packet->send_completion = netvsc_xmit_completion;
+       packet->send_completion_ctx = packet;
+       packet->send_completion_tid = (unsigned long)skb;
+
+       isvlan = packet->vlan_tci & VLAN_TAG_PRESENT;
+
+       /* Add the rndis header */
+       rndis_msg = packet->rndis_msg;
+       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 (isvlan) {
+               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 = packet->vlan_tci & VLAN_VID_MASK;
+               vlan->pri = (packet->vlan_tci & VLAN_PRIO_MASK) >>
+                               VLAN_PRIO_SHIFT;
+       }
+
+       net_trans_info = get_net_transport_info(skb, &hdr_offset);
+       if (net_trans_info == TRANSPORT_INFO_NOT_IP)
+               goto do_send;
+
+       /*
+        * Setup the sendside checksum offload only if this is not a
+        * GSO packet.
+        */
+       if (skb_is_gso(skb))
+               goto do_lso;
+
+       if ((skb->ip_summed == CHECKSUM_NONE) ||
+           (skb->ip_summed == CHECKSUM_UNNECESSARY))
+               goto do_send;
+
+       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;
+
+       if (net_trans_info & INFO_TCP) {
+               csum_info->transmit.tcp_checksum = 1;
+               csum_info->transmit.tcp_header_offset = hdr_offset;
+       } else if (net_trans_info & INFO_UDP) {
+               /* UDP checksum offload is not supported on ws2008r2.
+                * Furthermore, on ws2012 and ws2012r2, there are some
+                * issues with udp checksum offload from Linux guests.
+                * (these are host issues).
+                * For now compute the checksum here.
+                */
+               struct udphdr *uh;
+               u16 udp_len;
+
+               ret = skb_cow_head(skb, 0);
+               if (ret)
+                       goto drop;
+
+               uh = udp_hdr(skb);
+               udp_len = ntohs(uh->len);
+               uh->check = 0;
+               uh->check = csum_tcpudp_magic(ip_hdr(skb)->saddr,
+                                             ip_hdr(skb)->daddr,
+                                             udp_len, IPPROTO_UDP,
+                                             csum_partial(uh, udp_len, 0));
+               if (uh->check == 0)
+                       uh->check = CSUM_MANGLED_0;
+
+               csum_info->transmit.udp_checksum = 0;
+       }
+       goto do_send;
+
+do_lso:
+       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;
+
+do_send:
+       /* 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);
+
+       ret = netvsc_send(net_device_ctx->device_ctx, packet);
+
+drop:
+       if (ret == 0) {
+               net->stats.tx_bytes += skb_length;
+               net->stats.tx_packets++;
+       } else {
+               if (ret != -EAGAIN) {
+                       dev_kfree_skb_any(skb);
+                       net->stats.tx_dropped++;
+               }
+       }
+
+       return (ret == -EAGAIN) ? NETDEV_TX_BUSY : NETDEV_TX_OK;
+}
+
+/*
+ * 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_device *net_device;
+       struct rndis_device *rdev;
+
+       net_device = hv_get_drvdata(device_obj);
+       rdev = net_device->extension;
+
+       switch (indicate->status) {
+       case RNDIS_STATUS_MEDIA_CONNECT:
+               rdev->link_state = false;
+               break;
+       case RNDIS_STATUS_MEDIA_DISCONNECT:
+               rdev->link_state = true;
+               break;
+       case RNDIS_STATUS_NETWORK_CHANGE:
+               rdev->link_change = true;
+               break;
+       default:
+               return;
+       }
+
+       net = net_device->ndev;
+
+       if (!net || net->reg_state != NETREG_REGISTERED)
+               return;
+
+       ndev_ctx = netdev_priv(net);
+       if (!rdev->link_state) {
+               schedule_delayed_work(&ndev_ctx->dwork, 0);
+               schedule_delayed_work(&ndev_ctx->dwork, msecs_to_jiffies(20));
+       } else {
+               schedule_delayed_work(&ndev_ctx->dwork, 0);
+       }
+}
+
+/*
+ * 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,
+                               struct ndis_tcp_ip_checksum_info *csum_info)
+{
+       struct net_device *net;
+       struct sk_buff *skb;
+
+       net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
+       if (!net || net->reg_state != NETREG_REGISTERED) {
+               packet->status = NVSP_STAT_FAIL;
+               return 0;
+       }
+
+       /* Allocate a skb - TODO direct I/O to pages? */
+       skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
+       if (unlikely(!skb)) {
+               ++net->stats.rx_dropped;
+               packet->status = NVSP_STAT_FAIL;
+               return 0;
+       }
+
+       /*
+        * 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), packet->data,
+               packet->total_data_buflen);
+
+       skb->protocol = eth_type_trans(skb, net);
+       if (csum_info) {
+               /* We only look at the IP checksum here.
+                * Should we be dropping the packet if checksum
+                * failed? How do we deal with other checksums - TCP/UDP?
+                */
+               if (csum_info->receive.ip_checksum_succeeded)
+                       skb->ip_summed = CHECKSUM_UNNECESSARY;
+               else
+                       skb->ip_summed = CHECKSUM_NONE;
+       }
+
+       if (packet->vlan_tci & VLAN_TAG_PRESENT)
+               __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
+                                      packet->vlan_tci);
+
+       skb_record_rx_queue(skb, packet->channel->
+                           offermsg.offer.sub_channel_index);
+
+       net->stats.rx_packets++;
+       net->stats.rx_bytes += packet->total_data_buflen;
+
+       /*
+        * Pass the skb back up. Network stack will deallocate the skb when it
+        * is done.
+        * TODO - use NAPI?
+        */
+       netif_rx(skb);
+
+       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 hv_device *dev = net_device_ctx->device_ctx;
+       struct netvsc_device *nvdev = hv_get_drvdata(dev);
+
+       if (nvdev) {
+               channel->max_combined   = nvdev->max_chn;
+               channel->combined_count = nvdev->num_chn;
+       }
+}
+
+static int netvsc_change_mtu(struct net_device *ndev, int mtu)
+{
+       struct net_device_context *ndevctx = netdev_priv(ndev);
+       struct hv_device *hdev =  ndevctx->device_ctx;
+       struct netvsc_device *nvdev = hv_get_drvdata(hdev);
+       struct netvsc_device_info device_info;
+       int limit = ETH_DATA_LEN;
+
+       if (nvdev == NULL || nvdev->destroy)
+               return -ENODEV;
+
+       if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
+               limit = NETVSC_MTU - ETH_HLEN;
+
+       /* Hyper-V hosts don't support MTU < ETH_DATA_LEN (1500) */
+       if (mtu < ETH_DATA_LEN || mtu > limit)
+               return -EINVAL;
+
+       nvdev->start_remove = true;
+       cancel_work_sync(&ndevctx->work);
+       netif_tx_disable(ndev);
+       rndis_filter_device_remove(hdev);
+
+       ndev->mtu = mtu;
+
+       ndevctx->device_ctx = hdev;
+       hv_set_drvdata(hdev, ndev);
+       device_info.ring_size = ring_size;
+       rndis_filter_device_add(hdev, &device_info);
+       netif_tx_wake_all_queues(ndev);
+
+       return 0;
+}
+
+
+static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
+{
+       struct net_device_context *ndevctx = netdev_priv(ndev);
+       struct hv_device *hdev =  ndevctx->device_ctx;
+       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(hdev, 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;
+}
+
+#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_channels   = netvsc_get_channels,
+};
+
+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,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+       .ndo_poll_controller =          netvsc_poll_controller,
+#endif
+};
+
+/*
+ * Send GARP packet to network peers after migrations.
+ * After Quick Migration, the network is not immediately operational in the
+ * current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, add
+ * another netif_notify_peers() into a delayed work, otherwise GARP packet
+ * will not be sent after quick migration, and cause network disconnection.
+ * Also, we update the carrier status here.
+ */
+static void netvsc_link_change(struct work_struct *w)
+{
+       struct net_device_context *ndev_ctx;
+       struct net_device *net;
+       struct netvsc_device *net_device;
+       struct rndis_device *rdev;
+       bool notify, refresh = false;
+       char *argv[] = { "/etc/init.d/network", "restart", NULL };
+       char *envp[] = { "HOME=/", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL };
+
+       rtnl_lock();
+
+       ndev_ctx = container_of(w, struct net_device_context, dwork.work);
+       net_device = hv_get_drvdata(ndev_ctx->device_ctx);
+       rdev = net_device->extension;
+       net = net_device->ndev;
+
+       if (rdev->link_state) {
+               netif_carrier_off(net);
+               notify = false;
+       } else {
+               netif_carrier_on(net);
+               notify = true;
+               if (rdev->link_change) {
+                       rdev->link_change = false;
+                       refresh = true;
+               }
+       }
+
+       rtnl_unlock();
+
+       if (refresh)
+               call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+
+       if (notify)
+               netdev_notify_peers(net);
+}
+
+
+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;
+       u32 max_needed_headroom;
+
+       net = alloc_etherdev_mq(sizeof(struct net_device_context),
+                               num_online_cpus());
+       if (!net)
+               return -ENOMEM;
+
+       max_needed_headroom = sizeof(struct hv_netvsc_packet) +
+                             RNDIS_AND_PPI_SIZE;
+
+       netif_carrier_off(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\n",
+                          net_device_ctx->msg_enable);
+
+       hv_set_drvdata(dev, net);
+       INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
+       INIT_WORK(&net_device_ctx->work, do_set_multicast);
+
+       net->netdev_ops = &device_ops;
+
+       net->hw_features = NETIF_F_RXCSUM | NETIF_F_SG | NETIF_F_IP_CSUM |
+                               NETIF_F_TSO;
+       net->features = NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_SG | NETIF_F_RXCSUM |
+                       NETIF_F_IP_CSUM | NETIF_F_TSO;
+
+       net->ethtool_ops = &ethtool_ops;
+       SET_NETDEV_DEV(net, &dev->device);
+
+       /*
+        * Request additional head room in the skb.
+        * We will use this space to build the rndis
+        * heaser and other state we need to maintain.
+        */
+       net->needed_headroom = max_needed_headroom;
+
+       /* Notify the netvsc driver of the new device */
+       device_info.ring_size = ring_size;
+       ret = rndis_filter_device_add(dev, &device_info);
+       if (ret != 0) {
+               netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
+               free_netdev(net);
+               hv_set_drvdata(dev, NULL);
+               return ret;
+       }
+       memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
+
+       nvdev = hv_get_drvdata(dev);
+       netif_set_real_num_tx_queues(net, nvdev->num_chn);
+       netif_set_real_num_rx_queues(net, nvdev->num_chn);
+
+       ret = register_netdev(net);
+       if (ret != 0) {
+               pr_err("Unable to register netdev.\n");
+               rndis_filter_device_remove(dev);
+               free_netdev(net);
+       } else {
+               schedule_delayed_work(&net_device_ctx->dwork, 0);
+       }
+
+       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_device = hv_get_drvdata(dev);
+       net = net_device->ndev;
+
+       if (net == NULL) {
+               dev_err(&dev->device, "No net device to remove\n");
+               return 0;
+       }
+
+       net_device->start_remove = true;
+
+       ndev_ctx = netdev_priv(net);
+       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);
+
+       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,
+};
+
+static void __exit netvsc_drv_exit(void)
+{
+       vmbus_driver_unregister(&netvsc_drv);
+}
+
+static int __init netvsc_drv_init(void)
+{
+       if (ring_size < RING_SIZE_MIN) {
+               ring_size = RING_SIZE_MIN;
+               pr_info("Increased ring_size to %d (min allowed)\n",
+                       ring_size);
+       }
+       return vmbus_driver_register(&netvsc_drv);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Microsoft Hyper-V network driver");
+
+module_init(netvsc_drv_init);
+module_exit(netvsc_drv_exit);