// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2009, Microsoft Corporation.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 */
#include <linux/ethtool.h>
#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 <linux/rtnetlink.h>
#include <linux/ucs2_string.h>

#include "hyperv_net.h"
#include "netvsc_trace.h"

static void rndis_set_multicast(struct work_struct *w);

#define RNDIS_EXT_LEN HV_HYP_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 const u8 netvsc_hash_key[NETVSC_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 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);
        INIT_WORK(&device->mcast_work, rndis_set_multicast);

        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 net_device *netdev,
                               const struct rndis_message *rndis_msg,
                               const void *data)
{
        switch (rndis_msg->ndis_msg_type) {
        case RNDIS_MSG_PACKET:
                if (rndis_msg->msg_len - RNDIS_HEADER_SIZE >= sizeof(struct rndis_packet)) {
                        const struct rndis_packet *pkt = data + RNDIS_HEADER_SIZE;
                        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,
                                   pkt->data_offset,
                                   pkt->data_len,
                                   pkt->num_oob_data_elements,
                                   pkt->oob_data_offset,
                                   pkt->oob_data_len,
                                   pkt->per_pkt_info_offset,
                                   pkt->per_pkt_info_len);
                }
                break;

        case RNDIS_MSG_INIT_C:
                if (rndis_msg->msg_len - RNDIS_HEADER_SIZE >=
                                sizeof(struct rndis_initialize_complete)) {
                        const struct rndis_initialize_complete *init_complete =
                                data + RNDIS_HEADER_SIZE;
                        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,
                                init_complete->req_id,
                                init_complete->status,
                                init_complete->major_ver,
                                init_complete->minor_ver,
                                init_complete->dev_flags,
                                init_complete->max_xfer_size,
                                init_complete->max_pkt_per_msg,
                                init_complete->pkt_alignment_factor);
                }
                break;

        case RNDIS_MSG_QUERY_C:
                if (rndis_msg->msg_len - RNDIS_HEADER_SIZE >=
                                sizeof(struct rndis_query_complete)) {
                        const struct rndis_query_complete *query_complete =
                                data + RNDIS_HEADER_SIZE;
                        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,
                                query_complete->req_id,
                                query_complete->status,
                                query_complete->info_buflen,
                                query_complete->info_buf_offset);
                }
                break;

        case RNDIS_MSG_SET_C:
                if (rndis_msg->msg_len - RNDIS_HEADER_SIZE + sizeof(struct rndis_set_complete)) {
                        const struct rndis_set_complete *set_complete =
                                data + RNDIS_HEADER_SIZE;
                        netdev_dbg(netdev,
                                "RNDIS_MSG_SET_C (len %u, id 0x%x, status 0x%x)\n",
                                rndis_msg->msg_len,
                                set_complete->req_id,
                                set_complete->status);
                }
                break;

        case RNDIS_MSG_INDICATE:
                if (rndis_msg->msg_len - RNDIS_HEADER_SIZE >=
                                sizeof(struct rndis_indicate_status)) {
                        const struct rndis_indicate_status *indicate_status =
                                data + RNDIS_HEADER_SIZE;
                        netdev_dbg(netdev, "RNDIS_MSG_INDICATE "
                                "(len %u, status 0x%x, buf len %u, buf offset %u)\n",
                                rndis_msg->msg_len,
                                indicate_status->status,
                                indicate_status->status_buflen,
                                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)
{
        struct hv_netvsc_packet *packet;
        struct hv_page_buffer page_buf[2];
        struct hv_page_buffer *pb = page_buf;
        int ret;

        /* 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) >>
                                        HV_HYP_PAGE_SHIFT;
        pb[0].len = req->request_msg.msg_len;
        pb[0].offset = offset_in_hvpage(&req->request_msg);

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

        trace_rndis_send(dev->ndev, 0, &req->request_msg);

        rcu_read_lock_bh();
        ret = netvsc_send(dev->ndev, packet, NULL, pb, NULL, false);
        rcu_read_unlock_bh();

        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;
        u32 msg_len = request->response_msg.msg_len;

        /* Ensure the packet is big enough to access its fields */
        if (msg_len - RNDIS_HEADER_SIZE < sizeof(struct rndis_query_complete))
                return;

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

        if (query_complete->status == RNDIS_STATUS_SUCCESS &&
            query_complete->info_buflen >= sizeof(u32) &&
            query_complete->info_buf_offset >= sizeof(*query_complete) &&
            msg_len - RNDIS_HEADER_SIZE >= query_complete->info_buf_offset &&
            msg_len - RNDIS_HEADER_SIZE - query_complete->info_buf_offset
                        >= query_complete->info_buflen) {
                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 net_device *ndev,
                                          struct netvsc_device *nvdev,
                                          struct rndis_message *resp,
                                          void *data)
{
        u32 *req_id = &resp->msg.init_complete.req_id;
        struct rndis_device *dev = nvdev->extension;
        struct rndis_request *request = NULL;
        bool found = false;
        unsigned long flags;

        /* This should never happen, it means control message
         * response received after device removed.
         */
        if (dev->state == RNDIS_DEV_UNINITIALIZED) {
                netdev_err(ndev,
                           "got rndis message uninitialized\n");
                return;
        }

        /* Ensure the packet is big enough to read req_id. Req_id is the 1st
         * field in any request/response message, so the payload should have at
         * least sizeof(u32) bytes
         */
        if (resp->msg_len - RNDIS_HEADER_SIZE < sizeof(u32)) {
                netdev_err(ndev, "rndis msg_len too small: %u\n",
                           resp->msg_len);
                return;
        }

        /* Copy the request ID into nvchan->recv_buf */
        *req_id = *(u32 *)(data + RNDIS_HEADER_SIZE);

        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 == *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, RNDIS_HEADER_SIZE + sizeof(*req_id));
                        memcpy((void *)&request->response_msg + RNDIS_HEADER_SIZE + sizeof(*req_id),
                               data + RNDIS_HEADER_SIZE + sizeof(*req_id),
                               resp->msg_len - RNDIS_HEADER_SIZE - sizeof(*req_id));
                        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",
                        *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 net_device *ndev,
                                  struct rndis_packet *rpkt,
                                  u32 rpkt_len, u32 type, u8 internal,
                                  u32 ppi_size, void *data)
{
        struct rndis_per_packet_info *ppi;
        int len;

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

        /* Validate info_offset and info_len */
        if (rpkt->per_pkt_info_offset < sizeof(struct rndis_packet) ||
            rpkt->per_pkt_info_offset > rpkt_len) {
                netdev_err(ndev, "Invalid per_pkt_info_offset: %u\n",
                           rpkt->per_pkt_info_offset);
                return NULL;
        }

        if (rpkt->per_pkt_info_len < sizeof(*ppi) ||
            rpkt->per_pkt_info_len > rpkt_len - rpkt->per_pkt_info_offset) {
                netdev_err(ndev, "Invalid per_pkt_info_len: %u\n",
                           rpkt->per_pkt_info_len);
                return NULL;
        }

        ppi = (struct rndis_per_packet_info *)((ulong)rpkt +
                rpkt->per_pkt_info_offset);
        /* Copy the PPIs into nvchan->recv_buf */
        memcpy(ppi, data + RNDIS_HEADER_SIZE + rpkt->per_pkt_info_offset, rpkt->per_pkt_info_len);
        len = rpkt->per_pkt_info_len;

        while (len > 0) {
                /* Validate ppi_offset and ppi_size */
                if (ppi->size > len) {
                        netdev_err(ndev, "Invalid ppi size: %u\n", ppi->size);
                        continue;
                }

                if (ppi->ppi_offset >= ppi->size) {
                        netdev_err(ndev, "Invalid ppi_offset: %u\n", ppi->ppi_offset);
                        continue;
                }

                if (ppi->type == type && ppi->internal == internal) {
                        /* ppi->size should be big enough to hold the returned object. */
                        if (ppi->size - ppi->ppi_offset < ppi_size) {
                                netdev_err(ndev, "Invalid ppi: size %u ppi_offset %u\n",
                                           ppi->size, ppi->ppi_offset);
                                continue;
                        }
                        return (void *)((ulong)ppi + ppi->ppi_offset);
                }
                len -= ppi->size;
                ppi = (struct rndis_per_packet_info *)((ulong)ppi + ppi->size);
        }

        return NULL;
}

static inline
void rsc_add_data(struct netvsc_channel *nvchan,
                  const struct ndis_pkt_8021q_info *vlan,
                  const struct ndis_tcp_ip_checksum_info *csum_info,
                  const u32 *hash_info,
                  void *data, u32 len)
{
        u32 cnt = nvchan->rsc.cnt;

        if (cnt) {
                nvchan->rsc.pktlen += len;
        } else {
                /* The data/values pointed by vlan, csum_info and hash_info are shared
                 * across the different 'fragments' of the RSC packet; store them into
                 * the packet itself.
                 */
                if (vlan != NULL) {
                        memcpy(&nvchan->rsc.vlan, vlan, sizeof(*vlan));
                        nvchan->rsc.ppi_flags |= NVSC_RSC_VLAN;
                } else {
                        nvchan->rsc.ppi_flags &= ~NVSC_RSC_VLAN;
                }
                if (csum_info != NULL) {
                        memcpy(&nvchan->rsc.csum_info, csum_info, sizeof(*csum_info));
                        nvchan->rsc.ppi_flags |= NVSC_RSC_CSUM_INFO;
                } else {
                        nvchan->rsc.ppi_flags &= ~NVSC_RSC_CSUM_INFO;
                }
                nvchan->rsc.pktlen = len;
                if (hash_info != NULL) {
                        nvchan->rsc.hash_info = *hash_info;
                        nvchan->rsc.ppi_flags |= NVSC_RSC_HASH_INFO;
                } else {
                        nvchan->rsc.ppi_flags &= ~NVSC_RSC_HASH_INFO;
                }
        }

        nvchan->rsc.data[cnt] = data;
        nvchan->rsc.len[cnt] = len;
        nvchan->rsc.cnt++;
}

static int rndis_filter_receive_data(struct net_device *ndev,
                                     struct netvsc_device *nvdev,
                                     struct netvsc_channel *nvchan,
                                     struct rndis_message *msg,
                                     void *data, u32 data_buflen)
{
        struct rndis_packet *rndis_pkt = &msg->msg.pkt;
        const struct ndis_tcp_ip_checksum_info *csum_info;
        const struct ndis_pkt_8021q_info *vlan;
        const struct rndis_pktinfo_id *pktinfo_id;
        const u32 *hash_info;
        u32 data_offset, rpkt_len;
        bool rsc_more = false;
        int ret;

        /* Ensure data_buflen is big enough to read header fields */
        if (data_buflen < RNDIS_HEADER_SIZE + sizeof(struct rndis_packet)) {
                netdev_err(ndev, "invalid rndis pkt, data_buflen too small: %u\n",
                           data_buflen);
                return NVSP_STAT_FAIL;
        }

        /* Copy the RNDIS packet into nvchan->recv_buf */
        memcpy(rndis_pkt, data + RNDIS_HEADER_SIZE, sizeof(*rndis_pkt));

        /* Validate rndis_pkt offset */
        if (rndis_pkt->data_offset >= data_buflen - RNDIS_HEADER_SIZE) {
                netdev_err(ndev, "invalid rndis packet offset: %u\n",
                           rndis_pkt->data_offset);
                return NVSP_STAT_FAIL;
        }

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

        rpkt_len = data_buflen - RNDIS_HEADER_SIZE;
        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 (unlikely(data_buflen < rndis_pkt->data_len)) {
                netdev_err(ndev, "rndis message buffer "
                           "overflow detected (got %u, min %u)"
                           "...dropping this message!\n",
                           data_buflen, rndis_pkt->data_len);
                return NVSP_STAT_FAIL;
        }

        vlan = rndis_get_ppi(ndev, rndis_pkt, rpkt_len, IEEE_8021Q_INFO, 0, sizeof(*vlan),
                             data);

        csum_info = rndis_get_ppi(ndev, rndis_pkt, rpkt_len, TCPIP_CHKSUM_PKTINFO, 0,
                                  sizeof(*csum_info), data);

        hash_info = rndis_get_ppi(ndev, rndis_pkt, rpkt_len, NBL_HASH_VALUE, 0,
                                  sizeof(*hash_info), data);

        pktinfo_id = rndis_get_ppi(ndev, rndis_pkt, rpkt_len, RNDIS_PKTINFO_ID, 1,
                                   sizeof(*pktinfo_id), data);

        /* Identify RSC frags, drop erroneous packets */
        if (pktinfo_id && (pktinfo_id->flag & RNDIS_PKTINFO_SUBALLOC)) {
                if (pktinfo_id->flag & RNDIS_PKTINFO_1ST_FRAG)
                        nvchan->rsc.cnt = 0;
                else if (nvchan->rsc.cnt == 0)
                        goto drop;

                rsc_more = true;

                if (pktinfo_id->flag & RNDIS_PKTINFO_LAST_FRAG)
                        rsc_more = false;

                if (rsc_more && nvchan->rsc.is_last)
                        goto drop;
        } else {
                nvchan->rsc.cnt = 0;
        }

        if (unlikely(nvchan->rsc.cnt >= NVSP_RSC_MAX))
                goto drop;

        /* Put data into per channel structure.
         * Also, 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
         */
        rsc_add_data(nvchan, vlan, csum_info, hash_info,
                     data + data_offset, rndis_pkt->data_len);

        if (rsc_more)
                return NVSP_STAT_SUCCESS;

        ret = netvsc_recv_callback(ndev, nvdev, nvchan);
        nvchan->rsc.cnt = 0;

        return ret;

drop:
        return NVSP_STAT_FAIL;
}

int rndis_filter_receive(struct net_device *ndev,
                         struct netvsc_device *net_dev,
                         struct netvsc_channel *nvchan,
                         void *data, u32 buflen)
{
        struct net_device_context *net_device_ctx = netdev_priv(ndev);
        struct rndis_message *rndis_msg = nvchan->recv_buf;

        if (buflen < RNDIS_HEADER_SIZE) {
                netdev_err(ndev, "Invalid rndis_msg (buflen: %u)\n", buflen);
                return NVSP_STAT_FAIL;
        }

        /* Copy the RNDIS msg header into nvchan->recv_buf */
        memcpy(rndis_msg, data, RNDIS_HEADER_SIZE);

        /* Validate incoming rndis_message packet */
        if (rndis_msg->msg_len < RNDIS_HEADER_SIZE ||
            buflen < rndis_msg->msg_len) {
                netdev_err(ndev, "Invalid rndis_msg (buflen: %u, msg_len: %u)\n",
                           buflen, rndis_msg->msg_len);
                return NVSP_STAT_FAIL;
        }

        if (netif_msg_rx_status(net_device_ctx))
                dump_rndis_message(ndev, rndis_msg, data);

        switch (rndis_msg->ndis_msg_type) {
        case RNDIS_MSG_PACKET:
                return rndis_filter_receive_data(ndev, net_dev, nvchan,
                                                 rndis_msg, data, buflen);
        case RNDIS_MSG_INIT_C:
        case RNDIS_MSG_QUERY_C:
        case RNDIS_MSG_SET_C:
                /* completion msgs */
                rndis_filter_receive_response(ndev, net_dev, rndis_msg, data);
                break;

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

        return NVSP_STAT_SUCCESS;
}

static int rndis_filter_query_device(struct rndis_device *dev,
                                     struct netvsc_device *nvdev,
                                     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;
        u32 msg_len;
        int ret = 0;

        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_TCP_OFFLOAD_HARDWARE_CAPABILITIES) {
                struct ndis_offload *hwcaps;
                u32 nvsp_version = nvdev->nvsp_version;
                u8 ndis_rev;
                size_t size;

                if (nvsp_version >= NVSP_PROTOCOL_VERSION_5) {
                        ndis_rev = NDIS_OFFLOAD_PARAMETERS_REVISION_3;
                        size = NDIS_OFFLOAD_SIZE;
                } else if (nvsp_version >= NVSP_PROTOCOL_VERSION_4) {
                        ndis_rev = NDIS_OFFLOAD_PARAMETERS_REVISION_2;
                        size = NDIS_OFFLOAD_SIZE_6_1;
                } else {
                        ndis_rev = NDIS_OFFLOAD_PARAMETERS_REVISION_1;
                        size = NDIS_OFFLOAD_SIZE_6_0;
                }

                request->request_msg.msg_len += size;
                query->info_buflen = size;
                hwcaps = (struct ndis_offload *)
                        ((unsigned long)query + query->info_buf_offset);

                hwcaps->header.type = NDIS_OBJECT_TYPE_OFFLOAD;
                hwcaps->header.revision = ndis_rev;
                hwcaps->header.size = size;

        } else 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;

        wait_for_completion(&request->wait_event);

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

        /* Ensure the packet is big enough to access its fields */
        if (msg_len - RNDIS_HEADER_SIZE < sizeof(struct rndis_query_complete)) {
                ret = -1;
                goto cleanup;
        }

        if (query_complete->info_buflen > inresult_size ||
            query_complete->info_buf_offset < sizeof(*query_complete) ||
            msg_len - RNDIS_HEADER_SIZE < query_complete->info_buf_offset ||
            msg_len - RNDIS_HEADER_SIZE - query_complete->info_buf_offset
                        < query_complete->info_buflen) {
                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;
}

/* Get the hardware offload capabilities */
static int
rndis_query_hwcaps(struct rndis_device *dev, struct netvsc_device *net_device,
                   struct ndis_offload *caps)
{
        u32 caps_len = sizeof(*caps);
        int ret;

        memset(caps, 0, sizeof(*caps));

        ret = rndis_filter_query_device(dev, net_device,
                                        OID_TCP_OFFLOAD_HARDWARE_CAPABILITIES,
                                        caps, &caps_len);
        if (ret)
                return ret;

        if (caps->header.type != NDIS_OBJECT_TYPE_OFFLOAD) {
                netdev_warn(dev->ndev, "invalid NDIS objtype %#x\n",
                            caps->header.type);
                return -EINVAL;
        }

        if (caps->header.revision < NDIS_OFFLOAD_PARAMETERS_REVISION_1) {
                netdev_warn(dev->ndev, "invalid NDIS objrev %x\n",
                            caps->header.revision);
                return -EINVAL;
        }

        if (caps->header.size > caps_len ||
            caps->header.size < NDIS_OFFLOAD_SIZE_6_0) {
                netdev_warn(dev->ndev,
                            "invalid NDIS objsize %u, data size %u\n",
                            caps->header.size, caps_len);
                return -EINVAL;
        }

        return 0;
}

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

        return rndis_filter_query_device(dev, net_device,
                                      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 netvsc_device *nvdev,
                                const char *mac)
{
        struct rndis_device *rdev = nvdev->extension;
        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;

        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;

        wait_for_completion(&request->wait_event);

        set_complete = &request->response_msg.msg.set_complete;
        if (set_complete->status != RNDIS_STATUS_SUCCESS)
                ret = -EIO;

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

int
rndis_filter_set_offload_params(struct net_device *ndev,
                                struct netvsc_device *nvdev,
                                struct ndis_offload_params *req_offloads)
{
        struct rndis_device *rdev = nvdev->extension;
        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;
        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;

        wait_for_completion(&request->wait_event);
        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;
}

static int rndis_set_rss_param_msg(struct rndis_device *rdev,
                                   const u8 *rss_key, u16 flag)
{
        struct net_device *ndev = rdev->ndev;
        struct net_device_context *ndc = netdev_priv(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 + NETVSC_HASH_KEYLEN;
        struct ndis_recv_scale_param *rssp;
        u32 *itab;
        u8 *keyp;
        int i, ret;

        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 = flag;
        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 = NETVSC_HASH_KEYLEN;
        rssp->hashkey_offset = rssp->indirect_taboffset +
                               rssp->indirect_tabsize;

        /* Set indirection table entries */
        itab = (u32 *)(rssp + 1);
        for (i = 0; i < ITAB_NUM; i++)
                itab[i] = ndc->rx_table[i];

        /* Set hask key values */
        keyp = (u8 *)((unsigned long)rssp + rssp->hashkey_offset);
        memcpy(keyp, rss_key, NETVSC_HASH_KEYLEN);

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

        wait_for_completion(&request->wait_event);
        set_complete = &request->response_msg.msg.set_complete;
        if (set_complete->status == RNDIS_STATUS_SUCCESS) {
                if (!(flag & NDIS_RSS_PARAM_FLAG_DISABLE_RSS) &&
                    !(flag & NDIS_RSS_PARAM_FLAG_HASH_KEY_UNCHANGED))
                        memcpy(rdev->rss_key, rss_key, NETVSC_HASH_KEYLEN);

        } else {
                netdev_err(ndev, "Fail to set RSS parameters:0x%x\n",
                           set_complete->status);
                ret = -EINVAL;
        }

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

int rndis_filter_set_rss_param(struct rndis_device *rdev,
                               const u8 *rss_key)
{
        /* Disable RSS before change */
        rndis_set_rss_param_msg(rdev, rss_key,
                                NDIS_RSS_PARAM_FLAG_DISABLE_RSS);

        return rndis_set_rss_param_msg(rdev, rss_key, 0);
}

static int rndis_filter_query_device_link_status(struct rndis_device *dev,
                                                 struct netvsc_device *net_device)

{
        u32 size = sizeof(u32);
        u32 link_status;

        return rndis_filter_query_device(dev, net_device,
                                         RNDIS_OID_GEN_MEDIA_CONNECT_STATUS,
                                         &link_status, &size);
}

static int rndis_filter_query_link_speed(struct rndis_device *dev,
                                         struct netvsc_device *net_device)
{
        u32 size = sizeof(u32);
        u32 link_speed;
        struct net_device_context *ndc;
        int ret;

        ret = rndis_filter_query_device(dev, net_device,
                                        RNDIS_OID_GEN_LINK_SPEED,
                                        &link_speed, &size);

        if (!ret) {
                ndc = netdev_priv(dev->ndev);

                /* The link speed reported from host is in 100bps unit, so
                 * we convert it to Mbps here.
                 */
                ndc->speed = link_speed / 10000;
        }

        return ret;
}

static int rndis_filter_set_packet_filter(struct rndis_device *dev,
                                          u32 new_filter)
{
        struct rndis_request *request;
        struct rndis_set_request *set;
        int ret;

        if (dev->filter == new_filter)
                return 0;

        request = get_rndis_request(dev, RNDIS_MSG_SET,
                        RNDIS_MESSAGE_SIZE(struct rndis_set_request) +
                        sizeof(u32));
        if (!request)
                return -ENOMEM;

        /* 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 = offsetof(typeof(*set), info_buf);
        memcpy(set->info_buf, &new_filter, sizeof(u32));

        ret = rndis_filter_send_request(dev, request);
        if (ret == 0) {
                wait_for_completion(&request->wait_event);
                dev->filter = new_filter;
        }

        put_rndis_request(dev, request);

        return ret;
}

static void rndis_set_multicast(struct work_struct *w)
{
        struct rndis_device *rdev
                = container_of(w, struct rndis_device, mcast_work);
        u32 filter = NDIS_PACKET_TYPE_DIRECTED;
        unsigned int flags = rdev->ndev->flags;

        if (flags & IFF_PROMISC) {
                filter = NDIS_PACKET_TYPE_PROMISCUOUS;
        } else {
                if (!netdev_mc_empty(rdev->ndev) || (flags & IFF_ALLMULTI))
                        filter |= NDIS_PACKET_TYPE_ALL_MULTICAST;
                if (flags & IFF_BROADCAST)
                        filter |= NDIS_PACKET_TYPE_BROADCAST;
        }

        rndis_filter_set_packet_filter(rdev, filter);
}

void rndis_filter_update(struct netvsc_device *nvdev)
{
        struct rndis_device *rdev = nvdev->extension;

        schedule_work(&rdev->mcast_work);
}

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

        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;
        }

        wait_for_completion(&request->wait_event);

        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 bool netvsc_device_idle(const struct netvsc_device *nvdev)
{
        int i;

        for (i = 0; i < nvdev->num_chn; i++) {
                const struct netvsc_channel *nvchan = &nvdev->chan_table[i];

                if (nvchan->mrc.first != nvchan->mrc.next)
                        return false;

                if (atomic_read(&nvchan->queue_sends) > 0)
                        return false;
        }

        return true;
}

static void rndis_filter_halt_device(struct netvsc_device *nvdev,
                                     struct rndis_device *dev)
{
        struct rndis_request *request;
        struct rndis_halt_request *halt;

        /* 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:
        nvdev->destroy = true;

        /* Force flag to be ordered before waiting */
        wmb();

        /* Wait for all send completions */
        wait_event(nvdev->wait_drain, netvsc_device_idle(nvdev));

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

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;

        /* Make sure rndis_set_multicast doesn't re-enable filter! */
        cancel_work_sync(&dev->mcast_work);

        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 net_device *ndev =
                hv_get_drvdata(new_sc->primary_channel->device_obj);
        struct net_device_context *ndev_ctx = netdev_priv(ndev);
        struct netvsc_device *nvscdev;
        u16 chn_index = new_sc->offermsg.offer.sub_channel_index;
        struct netvsc_channel *nvchan;
        int ret;

        /* This is safe because this callback only happens when
         * new device is being setup and waiting on the channel_init_wait.
         */
        nvscdev = rcu_dereference_raw(ndev_ctx->nvdev);
        if (!nvscdev || chn_index >= nvscdev->num_chn)
                return;

        nvchan = nvscdev->chan_table + chn_index;

        /* Because the device uses NAPI, all the interrupt batching and
         * control is done via Net softirq, not the channel handling
         */
        set_channel_read_mode(new_sc, HV_CALL_ISR);

        /* Set the channel before opening.*/
        nvchan->channel = new_sc;

        new_sc->next_request_id_callback = vmbus_next_request_id;
        new_sc->request_addr_callback = vmbus_request_addr;
        new_sc->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes);
        new_sc->max_pkt_size = NETVSC_MAX_PKT_SIZE;

        ret = vmbus_open(new_sc, netvsc_ring_bytes,
                         netvsc_ring_bytes, NULL, 0,
                         netvsc_channel_cb, nvchan);
        if (ret == 0)
                napi_enable(&nvchan->napi);
        else
                netdev_notice(ndev, "sub channel open failed: %d\n", ret);

        if (atomic_inc_return(&nvscdev->open_chn) == nvscdev->num_chn)
                wake_up(&nvscdev->subchan_open);
}

/* Open sub-channels after completing the handling of the device probe.
 * This breaks overlap of processing the host message for the
 * new primary channel with the initialization of sub-channels.
 */
int rndis_set_subchannel(struct net_device *ndev,
                         struct netvsc_device *nvdev,
                         struct netvsc_device_info *dev_info)
{
        struct nvsp_message *init_packet = &nvdev->channel_init_pkt;
        struct net_device_context *ndev_ctx = netdev_priv(ndev);
        struct hv_device *hv_dev = ndev_ctx->device_ctx;
        struct rndis_device *rdev = nvdev->extension;
        int i, ret;

        ASSERT_RTNL();

        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 =
                                                nvdev->num_chn - 1;
        trace_nvsp_send(ndev, init_packet);

        ret = vmbus_sendpacket(hv_dev->channel, init_packet,
                               sizeof(struct nvsp_message),
                               (unsigned long)init_packet,
                               VM_PKT_DATA_INBAND,
                               VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
        if (ret) {
                netdev_err(ndev, "sub channel allocate send failed: %d\n", ret);
                return ret;
        }

        wait_for_completion(&nvdev->channel_init_wait);
        if (init_packet->msg.v5_msg.subchn_comp.status != NVSP_STAT_SUCCESS) {
                netdev_err(ndev, "sub channel request failed\n");
                return -EIO;
        }

        /* Check that number of allocated sub channel is within the expected range */
        if (init_packet->msg.v5_msg.subchn_comp.num_subchannels > nvdev->num_chn - 1) {
                netdev_err(ndev, "invalid number of allocated sub channel\n");
                return -EINVAL;
        }
        nvdev->num_chn = 1 +
                init_packet->msg.v5_msg.subchn_comp.num_subchannels;

        /* wait for all sub channels to open */
        wait_event(nvdev->subchan_open,
                   atomic_read(&nvdev->open_chn) == nvdev->num_chn);

        for (i = 0; i < VRSS_SEND_TAB_SIZE; i++)
                ndev_ctx->tx_table[i] = i % nvdev->num_chn;

        /* ignore failures from setting rss parameters, still have channels */
        if (dev_info)
                rndis_filter_set_rss_param(rdev, dev_info->rss_key);
        else
                rndis_filter_set_rss_param(rdev, netvsc_hash_key);

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

        return 0;
}

static int rndis_netdev_set_hwcaps(struct rndis_device *rndis_device,
                                   struct netvsc_device *nvdev)
{
        struct net_device *net = rndis_device->ndev;
        struct net_device_context *net_device_ctx = netdev_priv(net);
        struct ndis_offload hwcaps;
        struct ndis_offload_params offloads;
        unsigned int gso_max_size = GSO_MAX_SIZE;
        int ret;

        /* Find HW offload capabilities */
        ret = rndis_query_hwcaps(rndis_device, nvdev, &hwcaps);
        if (ret != 0)
                return ret;

        /* A value of zero means "no change"; now turn on what we want. */
        memset(&offloads, 0, sizeof(struct ndis_offload_params));

        /* Linux does not care about IP checksum, always does in kernel */
        offloads.ip_v4_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_DISABLED;

        /* Reset previously set hw_features flags */
        net->hw_features &= ~NETVSC_SUPPORTED_HW_FEATURES;
        net_device_ctx->tx_checksum_mask = 0;

        /* Compute tx offload settings based on hw capabilities */
        net->hw_features |= NETIF_F_RXCSUM;
        net->hw_features |= NETIF_F_SG;
        net->hw_features |= NETIF_F_RXHASH;

        if ((hwcaps.csum.ip4_txcsum & NDIS_TXCSUM_ALL_TCP4) == NDIS_TXCSUM_ALL_TCP4) {
                /* Can checksum TCP */
                net->hw_features |= NETIF_F_IP_CSUM;
                net_device_ctx->tx_checksum_mask |= TRANSPORT_INFO_IPV4_TCP;

                offloads.tcp_ip_v4_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;

                if (hwcaps.lsov2.ip4_encap & NDIS_OFFLOAD_ENCAP_8023) {
                        offloads.lso_v2_ipv4 = NDIS_OFFLOAD_PARAMETERS_LSOV2_ENABLED;
                        net->hw_features |= NETIF_F_TSO;

                        if (hwcaps.lsov2.ip4_maxsz < gso_max_size)
                                gso_max_size = hwcaps.lsov2.ip4_maxsz;
                }

                if (hwcaps.csum.ip4_txcsum & NDIS_TXCSUM_CAP_UDP4) {
                        offloads.udp_ip_v4_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
                        net_device_ctx->tx_checksum_mask |= TRANSPORT_INFO_IPV4_UDP;
                }
        }

        if ((hwcaps.csum.ip6_txcsum & NDIS_TXCSUM_ALL_TCP6) == NDIS_TXCSUM_ALL_TCP6) {
                net->hw_features |= NETIF_F_IPV6_CSUM;

                offloads.tcp_ip_v6_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
                net_device_ctx->tx_checksum_mask |= TRANSPORT_INFO_IPV6_TCP;

                if ((hwcaps.lsov2.ip6_encap & NDIS_OFFLOAD_ENCAP_8023) &&
                    (hwcaps.lsov2.ip6_opts & NDIS_LSOV2_CAP_IP6) == NDIS_LSOV2_CAP_IP6) {
                        offloads.lso_v2_ipv6 = NDIS_OFFLOAD_PARAMETERS_LSOV2_ENABLED;
                        net->hw_features |= NETIF_F_TSO6;

                        if (hwcaps.lsov2.ip6_maxsz < gso_max_size)
                                gso_max_size = hwcaps.lsov2.ip6_maxsz;
                }

                if (hwcaps.csum.ip6_txcsum & NDIS_TXCSUM_CAP_UDP6) {
                        offloads.udp_ip_v6_csum = NDIS_OFFLOAD_PARAMETERS_TX_RX_ENABLED;
                        net_device_ctx->tx_checksum_mask |= TRANSPORT_INFO_IPV6_UDP;
                }
        }

        if (hwcaps.rsc.ip4 && hwcaps.rsc.ip6) {
                net->hw_features |= NETIF_F_LRO;

                if (net->features & NETIF_F_LRO) {
                        offloads.rsc_ip_v4 = NDIS_OFFLOAD_PARAMETERS_RSC_ENABLED;
                        offloads.rsc_ip_v6 = NDIS_OFFLOAD_PARAMETERS_RSC_ENABLED;
                } else {
                        offloads.rsc_ip_v4 = NDIS_OFFLOAD_PARAMETERS_RSC_DISABLED;
                        offloads.rsc_ip_v6 = NDIS_OFFLOAD_PARAMETERS_RSC_DISABLED;
                }
        }

        /* In case some hw_features disappeared we need to remove them from
         * net->features list as they're no longer supported.
         */
        net->features &= ~NETVSC_SUPPORTED_HW_FEATURES | net->hw_features;

        netif_set_gso_max_size(net, gso_max_size);

        ret = rndis_filter_set_offload_params(net, nvdev, &offloads);

        return ret;
}

static void rndis_get_friendly_name(struct net_device *net,
                                    struct rndis_device *rndis_device,
                                    struct netvsc_device *net_device)
{
        ucs2_char_t wname[256];
        unsigned long len;
        u8 ifalias[256];
        u32 size;

        size = sizeof(wname);
        if (rndis_filter_query_device(rndis_device, net_device,
                                      RNDIS_OID_GEN_FRIENDLY_NAME,
                                      wname, &size) != 0)
                return; /* ignore if host does not support */

        if (size == 0)
                return; /* name not set */

        /* Convert Windows Unicode string to UTF-8 */
        len = ucs2_as_utf8(ifalias, wname, sizeof(ifalias));

        /* ignore the default value from host */
        if (strcmp(ifalias, "Network Adapter") != 0)
                dev_set_alias(net, ifalias, len);
}

struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
                                      struct netvsc_device_info *device_info)
{
        struct net_device *net = hv_get_drvdata(dev);
        struct net_device_context *ndc = netdev_priv(net);
        struct netvsc_device *net_device;
        struct rndis_device *rndis_device;
        struct ndis_recv_scale_cap rsscap;
        u32 rsscap_size = sizeof(struct ndis_recv_scale_cap);
        u32 mtu, size;
        u32 num_possible_rss_qs;
        int i, ret;

        rndis_device = get_rndis_device();
        if (!rndis_device)
                return ERR_PTR(-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
         */
        net_device = netvsc_device_add(dev, device_info);
        if (IS_ERR(net_device)) {
                kfree(rndis_device);
                return net_device;
        }

        /* Initialize the rndis device */
        net_device->max_chn = 1;
        net_device->num_chn = 1;

        net_device->extension = rndis_device;
        rndis_device->ndev = net;

        /* Send the rndis initialization message */
        ret = rndis_filter_init_device(rndis_device, net_device);
        if (ret != 0)
                goto err_dev_remv;

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

        /* Get the mac address */
        ret = rndis_filter_query_device_mac(rndis_device, net_device);
        if (ret != 0)
                goto err_dev_remv;

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

        /* Get friendly name as ifalias*/
        if (!net->ifalias)
                rndis_get_friendly_name(net, rndis_device, net_device);

        /* Query and set hardware capabilities */
        ret = rndis_netdev_set_hwcaps(rndis_device, net_device);
        if (ret != 0)
                goto err_dev_remv;

        rndis_filter_query_device_link_status(rndis_device, net_device);

        netdev_dbg(net, "Device MAC %pM link state %s\n",
                   rndis_device->hw_mac_adr,
                   rndis_device->link_state ? "down" : "up");

        if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
                goto out;

        rndis_filter_query_link_speed(rndis_device, net_device);

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

        /* This guarantees that num_possible_rss_qs <= num_online_cpus */
        num_possible_rss_qs = min_t(u32, num_online_cpus(),
                                    rsscap.num_recv_que);

        net_device->max_chn = min_t(u32, VRSS_CHANNEL_MAX, num_possible_rss_qs);

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

        if (!netif_is_rxfh_configured(net)) {
                for (i = 0; i < ITAB_NUM; i++)
                        ndc->rx_table[i] = ethtool_rxfh_indir_default(
                                                i, net_device->num_chn);
        }

        atomic_set(&net_device->open_chn, 1);
        vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);

        for (i = 1; i < net_device->num_chn; i++) {
                ret = netvsc_alloc_recv_comp_ring(net_device, i);
                if (ret) {
                        while (--i != 0)
                                vfree(net_device->chan_table[i].mrc.slots);
                        goto out;
                }
        }

        for (i = 1; i < net_device->num_chn; i++)
                netif_napi_add(net, &net_device->chan_table[i].napi,
                               netvsc_poll, NAPI_POLL_WEIGHT);

        return net_device;

out:
        /* setting up multiple channels failed */
        net_device->max_chn = 1;
        net_device->num_chn = 1;
        return net_device;

err_dev_remv:
        rndis_filter_device_remove(dev, net_device);
        return ERR_PTR(ret);
}

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

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

        netvsc_device_remove(dev);
}

int rndis_filter_open(struct netvsc_device *nvdev)
{
        if (!nvdev)
                return -EINVAL;

        return rndis_filter_open_device(nvdev->extension);
}

int rndis_filter_close(struct netvsc_device *nvdev)
{
        if (!nvdev)
                return -EINVAL;

        return rndis_filter_close_device(nvdev->extension);
}