/*
 * 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, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/if_vlan.h>
#include <linux/nls.h>

#include "hyperv_net.h"


#define RNDIS_EXT_LEN 100
struct rndis_request {
        struct list_head list_ent;
        struct completion  wait_event;

        struct rndis_message response_msg;
        /*
         * The buffer for extended info after the RNDIS response message. It's
         * referenced based on the data offset in the RNDIS message. Its size
         * is enough for current needs, and should be sufficient for the near
         * future.
         */
        u8 response_ext[RNDIS_EXT_LEN];

        /* Simplify allocation by having a netvsc packet inline */
        struct hv_netvsc_packet pkt;
        /* Set 2 pages for rndis requests crossing page boundary */
        struct hv_page_buffer buf[2];

        struct rndis_message request_msg;
        /*
         * The buffer for the extended info after the RNDIS request message.
         * It is referenced and sized in a similar way as response_ext.
         */
        u8 request_ext[RNDIS_EXT_LEN];
};

static void rndis_filter_send_completion(void *ctx);


static struct rndis_device *get_rndis_device(void)
{
        struct rndis_device *device;

        device = kzalloc(sizeof(struct rndis_device), GFP_KERNEL);
        if (!device)
                return NULL;

        spin_lock_init(&device->request_lock);

        INIT_LIST_HEAD(&device->req_list);

        device->state = RNDIS_DEV_UNINITIALIZED;

        return device;
}

static struct rndis_request *get_rndis_request(struct rndis_device *dev,
                                             u32 msg_type,
                                             u32 msg_len)
{
        struct rndis_request *request;
        struct rndis_message *rndis_msg;
        struct rndis_set_request *set;
        unsigned long flags;

        request = kzalloc(sizeof(struct rndis_request), GFP_KERNEL);
        if (!request)
                return NULL;

        init_completion(&request->wait_event);

        rndis_msg = &request->request_msg;
        rndis_msg->ndis_msg_type = msg_type;
        rndis_msg->msg_len = msg_len;

        /*
         * Set the request id. This field is always after the rndis header for
         * request/response packet types so we just used the SetRequest as a
         * template
         */
        set = &rndis_msg->msg.set_req;
        set->req_id = atomic_inc_return(&dev->new_req_id);

        /* Add to the request list */
        spin_lock_irqsave(&dev->request_lock, flags);
        list_add_tail(&request->list_ent, &dev->req_list);
        spin_unlock_irqrestore(&dev->request_lock, flags);

        return request;
}

static void put_rndis_request(struct rndis_device *dev,
                            struct rndis_request *req)
{
        unsigned long flags;

        spin_lock_irqsave(&dev->request_lock, flags);
        list_del(&req->list_ent);
        spin_unlock_irqrestore(&dev->request_lock, flags);

        kfree(req);
}

static void dump_rndis_message(struct hv_device *hv_dev,
                        struct rndis_message *rndis_msg)
{
        struct net_device *netdev;
        struct netvsc_device *net_device;

        net_device = hv_get_drvdata(hv_dev);
        netdev = net_device->ndev;

        switch (rndis_msg->ndis_msg_type) {
        case RNDIS_MSG_PACKET:
                netdev_dbg(netdev, "RNDIS_MSG_PACKET (len %u, "
                           "data offset %u data len %u, # oob %u, "
                           "oob offset %u, oob len %u, pkt offset %u, "
                           "pkt len %u\n",
                           rndis_msg->msg_len,
                           rndis_msg->msg.pkt.data_offset,
                           rndis_msg->msg.pkt.data_len,
                           rndis_msg->msg.pkt.num_oob_data_elements,
                           rndis_msg->msg.pkt.oob_data_offset,
                           rndis_msg->msg.pkt.oob_data_len,
                           rndis_msg->msg.pkt.per_pkt_info_offset,
                           rndis_msg->msg.pkt.per_pkt_info_len);
                break;

        case RNDIS_MSG_INIT_C:
                netdev_dbg(netdev, "RNDIS_MSG_INIT_C "
                        "(len %u, id 0x%x, status 0x%x, major %d, minor %d, "
                        "device flags %d, max xfer size 0x%x, max pkts %u, "
                        "pkt aligned %u)\n",
                        rndis_msg->msg_len,
                        rndis_msg->msg.init_complete.req_id,
                        rndis_msg->msg.init_complete.status,
                        rndis_msg->msg.init_complete.major_ver,
                        rndis_msg->msg.init_complete.minor_ver,
                        rndis_msg->msg.init_complete.dev_flags,
                        rndis_msg->msg.init_complete.max_xfer_size,
                        rndis_msg->msg.init_complete.
                           max_pkt_per_msg,
                        rndis_msg->msg.init_complete.
                           pkt_alignment_factor);
                break;

        case RNDIS_MSG_QUERY_C:
                netdev_dbg(netdev, "RNDIS_MSG_QUERY_C "
                        "(len %u, id 0x%x, status 0x%x, buf len %u, "
                        "buf offset %u)\n",
                        rndis_msg->msg_len,
                        rndis_msg->msg.query_complete.req_id,
                        rndis_msg->msg.query_complete.status,
                        rndis_msg->msg.query_complete.
                           info_buflen,
                        rndis_msg->msg.query_complete.
                           info_buf_offset);
                break;

        case RNDIS_MSG_SET_C:
                netdev_dbg(netdev,
                        "RNDIS_MSG_SET_C (len %u, id 0x%x, status 0x%x)\n",
                        rndis_msg->msg_len,
                        rndis_msg->msg.set_complete.req_id,
                        rndis_msg->msg.set_complete.status);
                break;

        case RNDIS_MSG_INDICATE:
                netdev_dbg(netdev, "RNDIS_MSG_INDICATE "
                        "(len %u, status 0x%x, buf len %u, buf offset %u)\n",
                        rndis_msg->msg_len,
                        rndis_msg->msg.indicate_status.status,
                        rndis_msg->msg.indicate_status.status_buflen,
                        rndis_msg->msg.indicate_status.status_buf_offset);
                break;

        default:
                netdev_dbg(netdev, "0x%x (len %u)\n",
                        rndis_msg->ndis_msg_type,
                        rndis_msg->msg_len);
                break;
        }
}

static int rndis_filter_send_request(struct rndis_device *dev,
                                  struct rndis_request *req)
{
        int ret;
        struct hv_netvsc_packet *packet;

        /* Setup the packet to send it */
        packet = &req->pkt;

        packet->is_data_pkt = false;
        packet->total_data_buflen = req->request_msg.msg_len;
        packet->page_buf_cnt = 1;

        packet->page_buf[0].pfn = virt_to_phys(&req->request_msg) >>
                                        PAGE_SHIFT;
        packet->page_buf[0].len = req->request_msg.msg_len;
        packet->page_buf[0].offset =
                (unsigned long)&req->request_msg & (PAGE_SIZE - 1);

        /* Add one page_buf when request_msg crossing page boundary */
        if (packet->page_buf[0].offset + packet->page_buf[0].len > PAGE_SIZE) {
                packet->page_buf_cnt++;
                packet->page_buf[0].len = PAGE_SIZE -
                        packet->page_buf[0].offset;
                packet->page_buf[1].pfn = virt_to_phys((void *)&req->request_msg
                        + packet->page_buf[0].len) >> PAGE_SHIFT;
                packet->page_buf[1].offset = 0;
                packet->page_buf[1].len = req->request_msg.msg_len -
                        packet->page_buf[0].len;
        }

        packet->completion.send.send_completion = NULL;

        ret = netvsc_send(dev->net_dev->dev, packet);
        return ret;
}

static void rndis_filter_receive_response(struct rndis_device *dev,
                                       struct rndis_message *resp)
{
        struct rndis_request *request = NULL;
        bool found = false;
        unsigned long flags;
        struct net_device *ndev;

        ndev = dev->net_dev->ndev;

        spin_lock_irqsave(&dev->request_lock, flags);
        list_for_each_entry(request, &dev->req_list, list_ent) {
                /*
                 * All request/response message contains RequestId as the 1st
                 * field
                 */
                if (request->request_msg.msg.init_req.req_id
                    == resp->msg.init_complete.req_id) {
                        found = true;
                        break;
                }
        }
        spin_unlock_irqrestore(&dev->request_lock, flags);

        if (found) {
                if (resp->msg_len <=
                    sizeof(struct rndis_message) + RNDIS_EXT_LEN) {
                        memcpy(&request->response_msg, resp,
                               resp->msg_len);
                } else {
                        netdev_err(ndev,
                                "rndis response buffer overflow "
                                "detected (size %u max %zu)\n",
                                resp->msg_len,
                                sizeof(struct rndis_filter_packet));

                        if (resp->ndis_msg_type ==
                            RNDIS_MSG_RESET_C) {
                                /* does not have a request id field */
                                request->response_msg.msg.reset_complete.
                                        status = RNDIS_STATUS_BUFFER_OVERFLOW;
                        } else {
                                request->response_msg.msg.
                                init_complete.status =
                                        RNDIS_STATUS_BUFFER_OVERFLOW;
                        }
                }

                complete(&request->wait_event);
        } else {
                netdev_err(ndev,
                        "no rndis request found for this response "
                        "(id 0x%x res type 0x%x)\n",
                        resp->msg.init_complete.req_id,
                        resp->ndis_msg_type);
        }
}

static void rndis_filter_receive_indicate_status(struct rndis_device *dev,
                                             struct rndis_message *resp)
{
        struct rndis_indicate_status *indicate =
                        &resp->msg.indicate_status;

        if (indicate->status == RNDIS_STATUS_MEDIA_CONNECT) {
                netvsc_linkstatus_callback(
                        dev->net_dev->dev, 1);
        } else if (indicate->status == RNDIS_STATUS_MEDIA_DISCONNECT) {
                netvsc_linkstatus_callback(
                        dev->net_dev->dev, 0);
        } else {
                /*
                 * TODO:
                 */
        }
}

/*
 * Get the Per-Packet-Info with the specified type
 * return NULL if not found.
 */
static inline void *rndis_get_ppi(struct rndis_packet *rpkt, u32 type)
{
        struct rndis_per_packet_info *ppi;
        int len;

        if (rpkt->per_pkt_info_offset == 0)
                return NULL;

        ppi = (struct rndis_per_packet_info *)((ulong)rpkt +
                rpkt->per_pkt_info_offset);
        len = rpkt->per_pkt_info_len;

        while (len > 0) {
                if (ppi->type == type)
                        return (void *)((ulong)ppi + ppi->ppi_offset);
                len -= ppi->size;
                ppi = (struct rndis_per_packet_info *)((ulong)ppi + ppi->size);
        }

        return NULL;
}

static void rndis_filter_receive_data(struct rndis_device *dev,
                                   struct rndis_message *msg,
                                   struct hv_netvsc_packet *pkt)
{
        struct rndis_packet *rndis_pkt;
        u32 data_offset;
        struct ndis_pkt_8021q_info *vlan;

        rndis_pkt = &msg->msg.pkt;

        /* Remove the rndis header and pass it back up the stack */
        data_offset = RNDIS_HEADER_SIZE + rndis_pkt->data_offset;

        pkt->total_data_buflen -= data_offset;

        /*
         * Make sure we got a valid RNDIS message, now total_data_buflen
         * should be the data packet size plus the trailer padding size
         */
        if (pkt->total_data_buflen < rndis_pkt->data_len) {
                netdev_err(dev->net_dev->ndev, "rndis message buffer "
                           "overflow detected (got %u, min %u)"
                           "...dropping this message!\n",
                           pkt->total_data_buflen, rndis_pkt->data_len);
                return;
        }

        /*
         * Remove the rndis trailer padding from rndis packet message
         * rndis_pkt->data_len tell us the real data length, we only copy
         * the data packet to the stack, without the rndis trailer padding
         */
        pkt->total_data_buflen = rndis_pkt->data_len;
        pkt->data = (void *)((unsigned long)pkt->data + data_offset);

        pkt->is_data_pkt = true;

        vlan = rndis_get_ppi(rndis_pkt, IEEE_8021Q_INFO);
        if (vlan) {
                pkt->vlan_tci = VLAN_TAG_PRESENT | vlan->vlanid |
                        (vlan->pri << VLAN_PRIO_SHIFT);
        } else {
                pkt->vlan_tci = 0;
        }

        netvsc_recv_callback(dev->net_dev->dev, pkt);
}

int rndis_filter_receive(struct hv_device *dev,
                                struct hv_netvsc_packet *pkt)
{
        struct netvsc_device *net_dev = hv_get_drvdata(dev);
        struct rndis_device *rndis_dev;
        struct rndis_message *rndis_msg;
        struct net_device *ndev;
        int ret = 0;

        if (!net_dev) {
                ret = -EINVAL;
                goto exit;
        }

        ndev = net_dev->ndev;

        /* Make sure the rndis device state is initialized */
        if (!net_dev->extension) {
                netdev_err(ndev, "got rndis message but no rndis device - "
                          "dropping this message!\n");
                ret = -ENODEV;
                goto exit;
        }

        rndis_dev = (struct rndis_device *)net_dev->extension;
        if (rndis_dev->state == RNDIS_DEV_UNINITIALIZED) {
                netdev_err(ndev, "got rndis message but rndis device "
                           "uninitialized...dropping this message!\n");
                ret = -ENODEV;
                goto exit;
        }

        rndis_msg = pkt->data;

        dump_rndis_message(dev, rndis_msg);

        switch (rndis_msg->ndis_msg_type) {
        case RNDIS_MSG_PACKET:
                /* data msg */
                rndis_filter_receive_data(rndis_dev, rndis_msg, pkt);
                break;

        case RNDIS_MSG_INIT_C:
        case RNDIS_MSG_QUERY_C:
        case RNDIS_MSG_SET_C:
                /* completion msgs */
                rndis_filter_receive_response(rndis_dev, rndis_msg);
                break;

        case RNDIS_MSG_INDICATE:
                /* notification msgs */
                rndis_filter_receive_indicate_status(rndis_dev, rndis_msg);
                break;
        default:
                netdev_err(ndev,
                        "unhandled rndis message (type %u len %u)\n",
                           rndis_msg->ndis_msg_type,
                           rndis_msg->msg_len);
                break;
        }

exit:
        if (ret != 0)
                pkt->status = NVSP_STAT_FAIL;

        return ret;
}

static int rndis_filter_query_device(struct rndis_device *dev, u32 oid,
                                  void *result, u32 *result_size)
{
        struct rndis_request *request;
        u32 inresult_size = *result_size;
        struct rndis_query_request *query;
        struct rndis_query_complete *query_complete;
        int ret = 0;
        int t;

        if (!result)
                return -EINVAL;

        *result_size = 0;
        request = get_rndis_request(dev, RNDIS_MSG_QUERY,
                        RNDIS_MESSAGE_SIZE(struct rndis_query_request));
        if (!request) {
                ret = -ENOMEM;
                goto cleanup;
        }

        /* Setup the rndis query */
        query = &request->request_msg.msg.query_req;
        query->oid = oid;
        query->info_buf_offset = sizeof(struct rndis_query_request);
        query->info_buflen = 0;
        query->dev_vc_handle = 0;

        ret = rndis_filter_send_request(dev, request);
        if (ret != 0)
                goto cleanup;

        t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
        if (t == 0) {
                ret = -ETIMEDOUT;
                goto cleanup;
        }

        /* Copy the response back */
        query_complete = &request->response_msg.msg.query_complete;

        if (query_complete->info_buflen > inresult_size) {
                ret = -1;
                goto cleanup;
        }

        memcpy(result,
               (void *)((unsigned long)query_complete +
                         query_complete->info_buf_offset),
               query_complete->info_buflen);

        *result_size = query_complete->info_buflen;

cleanup:
        if (request)
                put_rndis_request(dev, request);

        return ret;
}

static int rndis_filter_query_device_mac(struct rndis_device *dev)
{
        u32 size = ETH_ALEN;

        return rndis_filter_query_device(dev,
                                      RNDIS_OID_802_3_PERMANENT_ADDRESS,
                                      dev->hw_mac_adr, &size);
}

#define NWADR_STR "NetworkAddress"
#define NWADR_STRLEN 14

int rndis_filter_set_device_mac(struct hv_device *hdev, char *mac)
{
        struct netvsc_device *nvdev = hv_get_drvdata(hdev);
        struct rndis_device *rdev = nvdev->extension;
        struct net_device *ndev = nvdev->ndev;
        struct rndis_request *request;
        struct rndis_set_request *set;
        struct rndis_config_parameter_info *cpi;
        wchar_t *cfg_nwadr, *cfg_mac;
        struct rndis_set_complete *set_complete;
        char macstr[2*ETH_ALEN+1];
        u32 extlen = sizeof(struct rndis_config_parameter_info) +
                2*NWADR_STRLEN + 4*ETH_ALEN;
        int ret, t;

        request = get_rndis_request(rdev, RNDIS_MSG_SET,
                RNDIS_MESSAGE_SIZE(struct rndis_set_request) + extlen);
        if (!request)
                return -ENOMEM;

        set = &request->request_msg.msg.set_req;
        set->oid = RNDIS_OID_GEN_RNDIS_CONFIG_PARAMETER;
        set->info_buflen = extlen;
        set->info_buf_offset = sizeof(struct rndis_set_request);
        set->dev_vc_handle = 0;

        cpi = (struct rndis_config_parameter_info *)((ulong)set +
                set->info_buf_offset);
        cpi->parameter_name_offset =
                sizeof(struct rndis_config_parameter_info);
        /* Multiply by 2 because host needs 2 bytes (utf16) for each char */
        cpi->parameter_name_length = 2*NWADR_STRLEN;
        cpi->parameter_type = RNDIS_CONFIG_PARAM_TYPE_STRING;
        cpi->parameter_value_offset =
                cpi->parameter_name_offset + cpi->parameter_name_length;
        /* Multiply by 4 because each MAC byte displayed as 2 utf16 chars */
        cpi->parameter_value_length = 4*ETH_ALEN;

        cfg_nwadr = (wchar_t *)((ulong)cpi + cpi->parameter_name_offset);
        cfg_mac = (wchar_t *)((ulong)cpi + cpi->parameter_value_offset);
        ret = utf8s_to_utf16s(NWADR_STR, NWADR_STRLEN, UTF16_HOST_ENDIAN,
                              cfg_nwadr, NWADR_STRLEN);
        if (ret < 0)
                goto cleanup;
        snprintf(macstr, 2*ETH_ALEN+1, "%pm", mac);
        ret = utf8s_to_utf16s(macstr, 2*ETH_ALEN, UTF16_HOST_ENDIAN,
                              cfg_mac, 2*ETH_ALEN);
        if (ret < 0)
                goto cleanup;

        ret = rndis_filter_send_request(rdev, request);
        if (ret != 0)
                goto cleanup;

        t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
        if (t == 0) {
                netdev_err(ndev, "timeout before we got a set response...\n");
                /*
                 * can't put_rndis_request, since we may still receive a
                 * send-completion.
                 */
                return -EBUSY;
        } else {
                set_complete = &request->response_msg.msg.set_complete;
                if (set_complete->status != RNDIS_STATUS_SUCCESS) {
                        netdev_err(ndev, "Fail to set MAC on host side:0x%x\n",
                                   set_complete->status);
                        ret = -EINVAL;
                }
        }

cleanup:
        put_rndis_request(rdev, request);
        return ret;
}


static int rndis_filter_query_device_link_status(struct rndis_device *dev)
{
        u32 size = sizeof(u32);
        u32 link_status;
        int ret;

        ret = rndis_filter_query_device(dev,
                                      RNDIS_OID_GEN_MEDIA_CONNECT_STATUS,
                                      &link_status, &size);
        dev->link_state = (link_status != 0) ? true : false;

        return ret;
}

int rndis_filter_set_packet_filter(struct rndis_device *dev, u32 new_filter)
{
        struct rndis_request *request;
        struct rndis_set_request *set;
        struct rndis_set_complete *set_complete;
        u32 status;
        int ret, t;
        struct net_device *ndev;

        ndev = dev->net_dev->ndev;

        request = get_rndis_request(dev, RNDIS_MSG_SET,
                        RNDIS_MESSAGE_SIZE(struct rndis_set_request) +
                        sizeof(u32));
        if (!request) {
                ret = -ENOMEM;
                goto cleanup;
        }

        /* Setup the rndis set */
        set = &request->request_msg.msg.set_req;
        set->oid = RNDIS_OID_GEN_CURRENT_PACKET_FILTER;
        set->info_buflen = sizeof(u32);
        set->info_buf_offset = sizeof(struct rndis_set_request);

        memcpy((void *)(unsigned long)set + sizeof(struct rndis_set_request),
               &new_filter, sizeof(u32));

        ret = rndis_filter_send_request(dev, request);
        if (ret != 0)
                goto cleanup;

        t = wait_for_completion_timeout(&request->wait_event, 5*HZ);

        if (t == 0) {
                netdev_err(ndev,
                        "timeout before we got a set response...\n");
                ret = -ETIMEDOUT;
                /*
                 * We can't deallocate the request since we may still receive a
                 * send completion for it.
                 */
                goto exit;
        } else {
                set_complete = &request->response_msg.msg.set_complete;
                status = set_complete->status;
        }

cleanup:
        if (request)
                put_rndis_request(dev, request);
exit:
        return ret;
}


static int rndis_filter_init_device(struct rndis_device *dev)
{
        struct rndis_request *request;
        struct rndis_initialize_request *init;
        struct rndis_initialize_complete *init_complete;
        u32 status;
        int ret, t;

        request = get_rndis_request(dev, RNDIS_MSG_INIT,
                        RNDIS_MESSAGE_SIZE(struct rndis_initialize_request));
        if (!request) {
                ret = -ENOMEM;
                goto cleanup;
        }

        /* Setup the rndis set */
        init = &request->request_msg.msg.init_req;
        init->major_ver = RNDIS_MAJOR_VERSION;
        init->minor_ver = RNDIS_MINOR_VERSION;
        init->max_xfer_size = 0x4000;

        dev->state = RNDIS_DEV_INITIALIZING;

        ret = rndis_filter_send_request(dev, request);
        if (ret != 0) {
                dev->state = RNDIS_DEV_UNINITIALIZED;
                goto cleanup;
        }


        t = wait_for_completion_timeout(&request->wait_event, 5*HZ);

        if (t == 0) {
                ret = -ETIMEDOUT;
                goto cleanup;
        }

        init_complete = &request->response_msg.msg.init_complete;
        status = init_complete->status;
        if (status == RNDIS_STATUS_SUCCESS) {
                dev->state = RNDIS_DEV_INITIALIZED;
                ret = 0;
        } else {
                dev->state = RNDIS_DEV_UNINITIALIZED;
                ret = -EINVAL;
        }

cleanup:
        if (request)
                put_rndis_request(dev, request);

        return ret;
}

static void rndis_filter_halt_device(struct rndis_device *dev)
{
        struct rndis_request *request;
        struct rndis_halt_request *halt;
        struct netvsc_device *nvdev = dev->net_dev;
        struct hv_device *hdev = nvdev->dev;
        ulong flags;

        /* Attempt to do a rndis device halt */
        request = get_rndis_request(dev, RNDIS_MSG_HALT,
                                RNDIS_MESSAGE_SIZE(struct rndis_halt_request));
        if (!request)
                goto cleanup;

        /* Setup the rndis set */
        halt = &request->request_msg.msg.halt_req;
        halt->req_id = atomic_inc_return(&dev->new_req_id);

        /* Ignore return since this msg is optional. */
        rndis_filter_send_request(dev, request);

        dev->state = RNDIS_DEV_UNINITIALIZED;

cleanup:
        spin_lock_irqsave(&hdev->channel->inbound_lock, flags);
        nvdev->destroy = true;
        spin_unlock_irqrestore(&hdev->channel->inbound_lock, flags);

        /* Wait for all send completions */
        wait_event(nvdev->wait_drain,
                atomic_read(&nvdev->num_outstanding_sends) == 0);

        if (request)
                put_rndis_request(dev, request);
        return;
}

static int rndis_filter_open_device(struct rndis_device *dev)
{
        int ret;

        if (dev->state != RNDIS_DEV_INITIALIZED)
                return 0;

        ret = rndis_filter_set_packet_filter(dev,
                                         NDIS_PACKET_TYPE_BROADCAST |
                                         NDIS_PACKET_TYPE_ALL_MULTICAST |
                                         NDIS_PACKET_TYPE_DIRECTED);
        if (ret == 0)
                dev->state = RNDIS_DEV_DATAINITIALIZED;

        return ret;
}

static int rndis_filter_close_device(struct rndis_device *dev)
{
        int ret;

        if (dev->state != RNDIS_DEV_DATAINITIALIZED)
                return 0;

        ret = rndis_filter_set_packet_filter(dev, 0);
        if (ret == 0)
                dev->state = RNDIS_DEV_INITIALIZED;

        return ret;
}

int rndis_filter_device_add(struct hv_device *dev,
                                  void *additional_info)
{
        int ret;
        struct netvsc_device *net_device;
        struct rndis_device *rndis_device;
        struct netvsc_device_info *device_info = additional_info;

        rndis_device = get_rndis_device();
        if (!rndis_device)
                return -ENODEV;

        /*
         * Let the inner driver handle this first to create the netvsc channel
         * NOTE! Once the channel is created, we may get a receive callback
         * (RndisFilterOnReceive()) before this call is completed
         */
        ret = netvsc_device_add(dev, additional_info);
        if (ret != 0) {
                kfree(rndis_device);
                return ret;
        }


        /* Initialize the rndis device */
        net_device = hv_get_drvdata(dev);

        net_device->extension = rndis_device;
        rndis_device->net_dev = net_device;

        /* Send the rndis initialization message */
        ret = rndis_filter_init_device(rndis_device);
        if (ret != 0) {
                rndis_filter_device_remove(dev);
                return ret;
        }

        /* Get the mac address */
        ret = rndis_filter_query_device_mac(rndis_device);
        if (ret != 0) {
                rndis_filter_device_remove(dev);
                return ret;
        }

        memcpy(device_info->mac_adr, rndis_device->hw_mac_adr, ETH_ALEN);

        rndis_filter_query_device_link_status(rndis_device);

        device_info->link_state = rndis_device->link_state;

        dev_info(&dev->device, "Device MAC %pM link state %s\n",
                 rndis_device->hw_mac_adr,
                 device_info->link_state ? "down" : "up");

        return ret;
}

void rndis_filter_device_remove(struct hv_device *dev)
{
        struct netvsc_device *net_dev = hv_get_drvdata(dev);
        struct rndis_device *rndis_dev = net_dev->extension;

        /* Halt and release the rndis device */
        rndis_filter_halt_device(rndis_dev);

        kfree(rndis_dev);
        net_dev->extension = NULL;

        netvsc_device_remove(dev);
}


int rndis_filter_open(struct hv_device *dev)
{
        struct netvsc_device *net_device = hv_get_drvdata(dev);

        if (!net_device)
                return -EINVAL;

        return rndis_filter_open_device(net_device->extension);
}

int rndis_filter_close(struct hv_device *dev)
{
        struct netvsc_device *nvdev = hv_get_drvdata(dev);

        if (!nvdev)
                return -EINVAL;

        return rndis_filter_close_device(nvdev->extension);
}

int rndis_filter_send(struct hv_device *dev,
                             struct hv_netvsc_packet *pkt)
{
        int ret;
        struct rndis_filter_packet *filter_pkt;
        struct rndis_message *rndis_msg;
        struct rndis_packet *rndis_pkt;
        u32 rndis_msg_size;
        bool isvlan = pkt->vlan_tci & VLAN_TAG_PRESENT;

        /* Add the rndis header */
        filter_pkt = (struct rndis_filter_packet *)pkt->extension;

        rndis_msg = &filter_pkt->msg;
        rndis_msg_size = RNDIS_MESSAGE_SIZE(struct rndis_packet);
        if (isvlan)
                rndis_msg_size += NDIS_VLAN_PPI_SIZE;

        rndis_msg->ndis_msg_type = RNDIS_MSG_PACKET;
        rndis_msg->msg_len = pkt->total_data_buflen +
                                      rndis_msg_size;

        rndis_pkt = &rndis_msg->msg.pkt;
        rndis_pkt->data_offset = sizeof(struct rndis_packet);
        if (isvlan)
                rndis_pkt->data_offset += NDIS_VLAN_PPI_SIZE;
        rndis_pkt->data_len = pkt->total_data_buflen;

        if (isvlan) {
                struct rndis_per_packet_info *ppi;
                struct ndis_pkt_8021q_info *vlan;

                rndis_pkt->per_pkt_info_offset = sizeof(struct rndis_packet);
                rndis_pkt->per_pkt_info_len = NDIS_VLAN_PPI_SIZE;

                ppi = (struct rndis_per_packet_info *)((ulong)rndis_pkt +
                        rndis_pkt->per_pkt_info_offset);
                ppi->size = NDIS_VLAN_PPI_SIZE;
                ppi->type = IEEE_8021Q_INFO;
                ppi->ppi_offset = sizeof(struct rndis_per_packet_info);

                vlan = (struct ndis_pkt_8021q_info *)((ulong)ppi +
                        ppi->ppi_offset);
                vlan->vlanid = pkt->vlan_tci & VLAN_VID_MASK;
                vlan->pri = (pkt->vlan_tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
        }

        pkt->is_data_pkt = true;
        pkt->page_buf[0].pfn = virt_to_phys(rndis_msg) >> PAGE_SHIFT;
        pkt->page_buf[0].offset =
                        (unsigned long)rndis_msg & (PAGE_SIZE-1);
        pkt->page_buf[0].len = rndis_msg_size;

        /* Add one page_buf if the rndis msg goes beyond page boundary */
        if (pkt->page_buf[0].offset + rndis_msg_size > PAGE_SIZE) {
                int i;
                for (i = pkt->page_buf_cnt; i > 1; i--)
                        pkt->page_buf[i] = pkt->page_buf[i-1];
                pkt->page_buf_cnt++;
                pkt->page_buf[0].len = PAGE_SIZE - pkt->page_buf[0].offset;
                pkt->page_buf[1].pfn = virt_to_phys((void *)((ulong)
                        rndis_msg + pkt->page_buf[0].len)) >> PAGE_SHIFT;
                pkt->page_buf[1].offset = 0;
                pkt->page_buf[1].len = rndis_msg_size - pkt->page_buf[0].len;
        }

        /* Save the packet send completion and context */
        filter_pkt->completion = pkt->completion.send.send_completion;
        filter_pkt->completion_ctx =
                                pkt->completion.send.send_completion_ctx;

        /* Use ours */
        pkt->completion.send.send_completion = rndis_filter_send_completion;
        pkt->completion.send.send_completion_ctx = filter_pkt;

        ret = netvsc_send(dev, pkt);
        if (ret != 0) {
                /*
                 * Reset the completion to originals to allow retries from
                 * above
                 */
                pkt->completion.send.send_completion =
                                filter_pkt->completion;
                pkt->completion.send.send_completion_ctx =
                                filter_pkt->completion_ctx;
        }

        return ret;
}

static void rndis_filter_send_completion(void *ctx)
{
        struct rndis_filter_packet *filter_pkt = ctx;

        /* Pass it back to the original handler */
        filter_pkt->completion(filter_pkt->completion_ctx);
}