/*
 * 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>
 */
#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 <linux/vmalloc.h>

#include "hyperv_net.h"


#define RNDIS_EXT_LEN PAGE_SIZE
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;

        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 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;

        request->pkt.q_idx = 0;

        /*
         * 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;
        struct hv_page_buffer page_buf[2];
        struct hv_page_buffer *pb = page_buf;

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

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

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

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

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

static void rndis_set_link_state(struct rndis_device *rdev,
                                 struct rndis_request *request)
{
        u32 link_status;
        struct rndis_query_complete *query_complete;

        query_complete = &request->response_msg.msg.query_complete;

        if (query_complete->status == RNDIS_STATUS_SUCCESS &&
            query_complete->info_buflen == sizeof(u32)) {
                memcpy(&link_status, (void *)((unsigned long)query_complete +
                       query_complete->info_buf_offset), sizeof(u32));
                rdev->link_state = link_status != 0;
        }
}

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);
                        if (request->request_msg.ndis_msg_type ==
                            RNDIS_MSG_QUERY && request->request_msg.msg.
                            query_req.oid == RNDIS_OID_GEN_MEDIA_CONNECT_STATUS)
                                rndis_set_link_state(dev, request);
                } else {
                        netdev_err(ndev,
                                "rndis response buffer overflow "
                                "detected (size %u max %zu)\n",
                                resp->msg_len,
                                sizeof(struct rndis_message));

                        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);
        }
}

/*
 * 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 int rndis_filter_receive_data(struct rndis_device *dev,
                                   struct rndis_message *msg,
                                   struct hv_netvsc_packet *pkt,
                                   void **data,
                                   struct vmbus_channel *channel)
{
        struct rndis_packet *rndis_pkt;
        u32 data_offset;
        struct ndis_pkt_8021q_info *vlan;
        struct ndis_tcp_ip_checksum_info *csum_info;
        u16 vlan_tci = 0;

        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 NVSP_STAT_FAIL;
        }

        /*
         * 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;
        *data = (void *)((unsigned long)(*data) + data_offset);

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

        csum_info = rndis_get_ppi(rndis_pkt, TCPIP_CHKSUM_PKTINFO);
        return netvsc_recv_callback(dev->net_dev->dev, pkt, data,
                                    csum_info, channel, vlan_tci);
}

int rndis_filter_receive(struct hv_device *dev,
                                struct hv_netvsc_packet *pkt,
                                void **data,
                                struct vmbus_channel *channel)
{
        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 = NVSP_STAT_FAIL;
                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 = NVSP_STAT_FAIL;
                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 = NVSP_STAT_FAIL;
                goto exit;
        }

        rndis_msg = *data;

        if (netif_msg_rx_err(net_dev->nd_ctx))
                dump_rndis_message(dev, rndis_msg);

        switch (rndis_msg->ndis_msg_type) {
        case RNDIS_MSG_PACKET:
                /* data msg */
                ret = rndis_filter_receive_data(rndis_dev, rndis_msg, pkt,
                                                data, channel);
                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 */
                netvsc_linkstatus_callback(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:
        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;
        unsigned long 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;

        if (oid == OID_GEN_RECEIVE_SCALE_CAPABILITIES) {
                struct ndis_recv_scale_cap *cap;

                request->request_msg.msg_len +=
                        sizeof(struct ndis_recv_scale_cap);
                query->info_buflen = sizeof(struct ndis_recv_scale_cap);
                cap = (struct ndis_recv_scale_cap *)((unsigned long)query +
                                                     query->info_buf_offset);
                cap->hdr.type = NDIS_OBJECT_TYPE_RSS_CAPABILITIES;
                cap->hdr.rev = NDIS_RECEIVE_SCALE_CAPABILITIES_REVISION_2;
                cap->hdr.size = sizeof(struct ndis_recv_scale_cap);
        }

        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;
        unsigned long 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_set_offload_params(struct hv_device *hdev,
                                struct ndis_offload_params *req_offloads)
{
        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 ndis_offload_params *offload_params;
        struct rndis_set_complete *set_complete;
        u32 extlen = sizeof(struct ndis_offload_params);
        int ret;
        unsigned long t;
        u32 vsp_version = nvdev->nvsp_version;

        if (vsp_version <= NVSP_PROTOCOL_VERSION_4) {
                extlen = VERSION_4_OFFLOAD_SIZE;
                /* On NVSP_PROTOCOL_VERSION_4 and below, we do not support
                 * UDP checksum offload.
                 */
                req_offloads->udp_ip_v4_csum = 0;
                req_offloads->udp_ip_v6_csum = 0;
        }

        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 = OID_TCP_OFFLOAD_PARAMETERS;
        set->info_buflen = extlen;
        set->info_buf_offset = sizeof(struct rndis_set_request);
        set->dev_vc_handle = 0;

        offload_params = (struct ndis_offload_params *)((ulong)set +
                                set->info_buf_offset);
        *offload_params = *req_offloads;
        offload_params->header.type = NDIS_OBJECT_TYPE_DEFAULT;
        offload_params->header.revision = NDIS_OFFLOAD_PARAMETERS_REVISION_3;
        offload_params->header.size = extlen;

        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 aOFFLOAD 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 offload on host side:0x%x\n",
                                   set_complete->status);
                        ret = -EINVAL;
                }
        }

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

u8 netvsc_hash_key[HASH_KEYLEN] = {
        0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2,
        0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0,
        0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4,
        0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c,
        0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa
};

static int rndis_filter_set_rss_param(struct rndis_device *rdev, int num_queue)
{
        struct net_device *ndev = rdev->net_dev->ndev;
        struct rndis_request *request;
        struct rndis_set_request *set;
        struct rndis_set_complete *set_complete;
        u32 extlen = sizeof(struct ndis_recv_scale_param) +
                     4*ITAB_NUM + HASH_KEYLEN;
        struct ndis_recv_scale_param *rssp;
        u32 *itab;
        u8 *keyp;
        int i, ret;
        unsigned long 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 = OID_GEN_RECEIVE_SCALE_PARAMETERS;
        set->info_buflen = extlen;
        set->info_buf_offset = sizeof(struct rndis_set_request);
        set->dev_vc_handle = 0;

        rssp = (struct ndis_recv_scale_param *)(set + 1);
        rssp->hdr.type = NDIS_OBJECT_TYPE_RSS_PARAMETERS;
        rssp->hdr.rev = NDIS_RECEIVE_SCALE_PARAMETERS_REVISION_2;
        rssp->hdr.size = sizeof(struct ndis_recv_scale_param);
        rssp->flag = 0;
        rssp->hashinfo = NDIS_HASH_FUNC_TOEPLITZ | NDIS_HASH_IPV4 |
                         NDIS_HASH_TCP_IPV4 | NDIS_HASH_IPV6 |
                         NDIS_HASH_TCP_IPV6;
        rssp->indirect_tabsize = 4*ITAB_NUM;
        rssp->indirect_taboffset = sizeof(struct ndis_recv_scale_param);
        rssp->hashkey_size = HASH_KEYLEN;
        rssp->kashkey_offset = rssp->indirect_taboffset +
                               rssp->indirect_tabsize;

        /* Set indirection table entries */
        itab = (u32 *)(rssp + 1);
        for (i = 0; i < ITAB_NUM; i++)
                itab[i] = i % num_queue;

        /* Set hask key values */
        keyp = (u8 *)((unsigned long)rssp + rssp->kashkey_offset);
        for (i = 0; i < HASH_KEYLEN; i++)
                keyp[i] = netvsc_hash_key[i];


        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 -ETIMEDOUT;
        } else {
                set_complete = &request->response_msg.msg.set_complete;
                if (set_complete->status != RNDIS_STATUS_SUCCESS) {
                        netdev_err(ndev, "Fail to set RSS parameters: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);

        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;
        unsigned long 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;
        unsigned long t;
        struct netvsc_device *nvdev = dev->net_dev;

        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;
                nvdev->max_pkt = init_complete->max_pkt_per_msg;
                nvdev->pkt_align = 1 << init_complete->pkt_alignment_factor;
                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 == -ENODEV)
                ret = 0;

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

        return ret;
}

static void netvsc_sc_open(struct vmbus_channel *new_sc)
{
        struct netvsc_device *nvscdev;
        u16 chn_index = new_sc->offermsg.offer.sub_channel_index;
        int ret;
        unsigned long flags;

        nvscdev = hv_get_drvdata(new_sc->primary_channel->device_obj);

        if (chn_index >= nvscdev->num_chn)
                return;

        set_per_channel_state(new_sc, nvscdev->sub_cb_buf + (chn_index - 1) *
                              NETVSC_PACKET_SIZE);

        ret = vmbus_open(new_sc, nvscdev->ring_size * PAGE_SIZE,
                         nvscdev->ring_size * PAGE_SIZE, NULL, 0,
                         netvsc_channel_cb, new_sc);

        if (ret == 0)
                nvscdev->chn_table[chn_index] = new_sc;

        spin_lock_irqsave(&nvscdev->sc_lock, flags);
        nvscdev->num_sc_offered--;
        spin_unlock_irqrestore(&nvscdev->sc_lock, flags);
        if (nvscdev->num_sc_offered == 0)
                complete(&nvscdev->channel_init_wait);
}

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;
        struct ndis_offload_params offloads;
        struct nvsp_message *init_packet;
        unsigned long t;
        struct ndis_recv_scale_cap rsscap;
        u32 rsscap_size = sizeof(struct ndis_recv_scale_cap);
        u32 mtu, size;
        u32 num_rss_qs;
        u32 sc_delta;
        const struct cpumask *node_cpu_mask;
        u32 num_possible_rss_qs;
        unsigned long flags;

        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->max_chn = 1;
        net_device->num_chn = 1;

        spin_lock_init(&net_device->sc_lock);

        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 MTU from the host */
        size = sizeof(u32);
        ret = rndis_filter_query_device(rndis_device,
                                        RNDIS_OID_GEN_MAXIMUM_FRAME_SIZE,
                                        &mtu, &size);
        if (ret == 0 && size == sizeof(u32) && mtu < net_device->ndev->mtu)
                net_device->ndev->mtu = mtu;

        /* 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);

        /* Turn on the offloads; the host supports all of the relevant
         * offloads.
         */
        memset(&offloads, 0, sizeof(struct ndis_offload_params));
        /* A value of zero means "no change"; now turn on what we
         * want.
         */
        offloads.ip_v4_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
        offloads.tcp_ip_v4_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
        offloads.udp_ip_v4_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
        offloads.tcp_ip_v6_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
        offloads.udp_ip_v6_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
        offloads.lso_v2_ipv4 = NDIS_OFFLOAD_PARAMETERS_LSOV2_ENABLED;


        ret = rndis_filter_set_offload_params(dev, &offloads);
        if (ret)
                goto err_dev_remv;

        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");

        if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
                return 0;

        /* vRSS setup */
        memset(&rsscap, 0, rsscap_size);
        ret = rndis_filter_query_device(rndis_device,
                                        OID_GEN_RECEIVE_SCALE_CAPABILITIES,
                                        &rsscap, &rsscap_size);
        if (ret || rsscap.num_recv_que < 2)
                goto out;

        net_device->max_chn = min_t(u32, VRSS_CHANNEL_MAX, rsscap.num_recv_que);

        num_rss_qs = min(device_info->max_num_vrss_chns, net_device->max_chn);

        /*
         * We will limit the VRSS channels to the number CPUs in the NUMA node
         * the primary channel is currently bound to.
         */
        node_cpu_mask = cpumask_of_node(cpu_to_node(dev->channel->target_cpu));
        num_possible_rss_qs = cpumask_weight(node_cpu_mask);

        /* We will use the given number of channels if available. */
        if (device_info->num_chn && device_info->num_chn < net_device->max_chn)
                net_device->num_chn = device_info->num_chn;
        else
                net_device->num_chn = min(num_possible_rss_qs, num_rss_qs);

        num_rss_qs = net_device->num_chn - 1;
        net_device->num_sc_offered = num_rss_qs;

        if (net_device->num_chn == 1)
                goto out;

        net_device->sub_cb_buf = vzalloc((net_device->num_chn - 1) *
                                         NETVSC_PACKET_SIZE);
        if (!net_device->sub_cb_buf) {
                net_device->num_chn = 1;
                dev_info(&dev->device, "No memory for subchannels.\n");
                goto out;
        }

        vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);

        init_packet = &net_device->channel_init_pkt;
        memset(init_packet, 0, sizeof(struct nvsp_message));
        init_packet->hdr.msg_type = NVSP_MSG5_TYPE_SUBCHANNEL;
        init_packet->msg.v5_msg.subchn_req.op = NVSP_SUBCHANNEL_ALLOCATE;
        init_packet->msg.v5_msg.subchn_req.num_subchannels =
                                                net_device->num_chn - 1;
        ret = vmbus_sendpacket(dev->channel, init_packet,
                               sizeof(struct nvsp_message),
                               (unsigned long)init_packet,
                               VM_PKT_DATA_INBAND,
                               VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
        if (ret)
                goto out;
        t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);
        if (t == 0) {
                ret = -ETIMEDOUT;
                goto out;
        }
        if (init_packet->msg.v5_msg.subchn_comp.status !=
            NVSP_STAT_SUCCESS) {
                ret = -ENODEV;
                goto out;
        }
        net_device->num_chn = 1 +
                init_packet->msg.v5_msg.subchn_comp.num_subchannels;

        ret = rndis_filter_set_rss_param(rndis_device, net_device->num_chn);

        /*
         * Set the number of sub-channels to be received.
         */
        spin_lock_irqsave(&net_device->sc_lock, flags);
        sc_delta = num_rss_qs - (net_device->num_chn - 1);
        net_device->num_sc_offered -= sc_delta;
        spin_unlock_irqrestore(&net_device->sc_lock, flags);

out:
        if (ret) {
                net_device->max_chn = 1;
                net_device->num_chn = 1;
                net_device->num_sc_offered = 0;
        }

        return 0; /* return 0 because primary channel can be used alone */

err_dev_remv:
        rndis_filter_device_remove(dev);
        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;
        unsigned long t;

        /* If not all subchannel offers are complete, wait for them until
         * completion to avoid race.
         */
        while (net_dev->num_sc_offered > 0) {
                t = wait_for_completion_timeout(&net_dev->channel_init_wait,
                                                10 * HZ);
                if (t == 0)
                        WARN(1, "Netvsc: Waiting for sub-channel processing");
        }

        /* 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);
}