Archipelago » qemu

/*

 * Virtio Network Device

 *

 * Copyright IBM, Corp. 2007

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 *

 */

#include "virtio.h"

#include "net.h"

#include "qemu-timer.h"

#include "virtio-net.h"

#define VIRTIO_NET_VM_VERSION    10

#define MAC_TABLE_ENTRIES    64

#define MAX_VLAN    (1 << 12)   /* Per 802.1Q definition */

typedef struct VirtIONet

{

    VirtIODevice vdev;

    uint8_t mac[ETH_ALEN];

    uint16_t status;

    VirtQueue *rx_vq;

    VirtQueue *tx_vq;

    VirtQueue *ctrl_vq;

    VLANClientState *vc;

    QEMUTimer *tx_timer;

    int tx_timer_active;

    struct {

        VirtQueueElement elem;

        ssize_t len;

    } async_tx;

    int mergeable_rx_bufs;

    uint8_t promisc;

    uint8_t allmulti;

    uint8_t alluni;

    uint8_t nomulti;

    uint8_t nouni;

    uint8_t nobcast;

    struct {

        int in_use;

        int first_multi;

        uint8_t multi_overflow;

        uint8_t uni_overflow;

        uint8_t *macs;

    } mac_table;

    uint32_t *vlans;

} VirtIONet;

/* TODO

 * - we could suppress RX interrupt if we were so inclined.

 */

static VirtIONet *to_virtio_net(VirtIODevice *vdev)

{

    return (VirtIONet *)vdev;

}

static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)

{

    VirtIONet *n = to_virtio_net(vdev);

    struct virtio_net_config netcfg;

    netcfg.status = n->status;

    memcpy(netcfg.mac, n->mac, ETH_ALEN);

    memcpy(config, &netcfg, sizeof(netcfg));

}

static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config)

{

    VirtIONet *n = to_virtio_net(vdev);

    struct virtio_net_config netcfg;

    memcpy(&netcfg, config, sizeof(netcfg));

    if (memcmp(netcfg.mac, n->mac, ETH_ALEN)) {

        memcpy(n->mac, netcfg.mac, ETH_ALEN);

        qemu_format_nic_info_str(n->vc, n->mac);

    }

}

static void virtio_net_set_link_status(VLANClientState *vc)

{

    VirtIONet *n = vc->opaque;

    uint16_t old_status = n->status;

    if (vc->link_down)

        n->status &= ~VIRTIO_NET_S_LINK_UP;

    else

        n->status |= VIRTIO_NET_S_LINK_UP;

    if (n->status != old_status)

        virtio_notify_config(&n->vdev);

}

static void virtio_net_reset(VirtIODevice *vdev)

{

    VirtIONet *n = to_virtio_net(vdev);

    /* Reset back to compatibility mode */

    n->promisc = 1;

    n->allmulti = 0;

    n->alluni = 0;

    n->nomulti = 0;

    n->nouni = 0;

    n->nobcast = 0;

    /* Flush any MAC and VLAN filter table state */

    n->mac_table.in_use = 0;

    n->mac_table.first_multi = 0;

    n->mac_table.multi_overflow = 0;

    n->mac_table.uni_overflow = 0;

    memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);

    memset(n->vlans, 0, MAX_VLAN >> 3);

}

static uint32_t virtio_net_get_features(VirtIODevice *vdev)

{

    uint32_t features = (1 << VIRTIO_NET_F_MAC) |

                        (1 << VIRTIO_NET_F_MRG_RXBUF) |

                        (1 << VIRTIO_NET_F_STATUS) |

                        (1 << VIRTIO_NET_F_CTRL_VQ) |

                        (1 << VIRTIO_NET_F_CTRL_RX) |

                        (1 << VIRTIO_NET_F_CTRL_VLAN) |

                        (1 << VIRTIO_NET_F_CTRL_RX_EXTRA);

    return features;

}

static uint32_t virtio_net_bad_features(VirtIODevice *vdev)

{

    uint32_t features = 0;

    /* Linux kernel 2.6.25.  It understood MAC (as everyone must),

     * but also these: */

    features |= (1 << VIRTIO_NET_F_MAC);

    features |= (1 << VIRTIO_NET_F_GUEST_CSUM);

    features |= (1 << VIRTIO_NET_F_GUEST_TSO4);

    features |= (1 << VIRTIO_NET_F_GUEST_TSO6);

    features |= (1 << VIRTIO_NET_F_GUEST_ECN);

    return features & virtio_net_get_features(vdev);

}

static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)

{

    VirtIONet *n = to_virtio_net(vdev);

    n->mergeable_rx_bufs = !!(features & (1 << VIRTIO_NET_F_MRG_RXBUF));

}

static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd,

                                     VirtQueueElement *elem)

{

    uint8_t on;

    if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(on)) {

        fprintf(stderr, "virtio-net ctrl invalid rx mode command\n");

        exit(1);

    }

    on = ldub_p(elem->out_sg[1].iov_base);

    if (cmd == VIRTIO_NET_CTRL_RX_MODE_PROMISC)

        n->promisc = on;

    else if (cmd == VIRTIO_NET_CTRL_RX_MODE_ALLMULTI)

        n->allmulti = on;

    else if (cmd == VIRTIO_NET_CTRL_RX_MODE_ALLUNI)

        n->alluni = on;

    else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOMULTI)

        n->nomulti = on;

    else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOUNI)

        n->nouni = on;

    else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOBCAST)

        n->nobcast = on;

    else

        return VIRTIO_NET_ERR;

    return VIRTIO_NET_OK;

}

static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,

                                 VirtQueueElement *elem)

{

    struct virtio_net_ctrl_mac mac_data;

    if (cmd != VIRTIO_NET_CTRL_MAC_TABLE_SET || elem->out_num != 3 ||

        elem->out_sg[1].iov_len < sizeof(mac_data) ||

        elem->out_sg[2].iov_len < sizeof(mac_data))

        return VIRTIO_NET_ERR;

    n->mac_table.in_use = 0;

    n->mac_table.first_multi = 0;

    n->mac_table.uni_overflow = 0;

    n->mac_table.multi_overflow = 0;

    memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);

    mac_data.entries = ldl_le_p(elem->out_sg[1].iov_base);

    if (sizeof(mac_data.entries) +

        (mac_data.entries * ETH_ALEN) > elem->out_sg[1].iov_len)

        return VIRTIO_NET_ERR;

    if (mac_data.entries <= MAC_TABLE_ENTRIES) {

        memcpy(n->mac_table.macs, elem->out_sg[1].iov_base + sizeof(mac_data),

               mac_data.entries * ETH_ALEN);

        n->mac_table.in_use += mac_data.entries;

    } else {

        n->mac_table.uni_overflow = 1;

    }

    n->mac_table.first_multi = n->mac_table.in_use;

    mac_data.entries = ldl_le_p(elem->out_sg[2].iov_base);

    if (sizeof(mac_data.entries) +

        (mac_data.entries * ETH_ALEN) > elem->out_sg[2].iov_len)

        return VIRTIO_NET_ERR;

    if (mac_data.entries) {

        if (n->mac_table.in_use + mac_data.entries <= MAC_TABLE_ENTRIES) {

            memcpy(n->mac_table.macs + (n->mac_table.in_use * ETH_ALEN),

                   elem->out_sg[2].iov_base + sizeof(mac_data),

                   mac_data.entries * ETH_ALEN);

            n->mac_table.in_use += mac_data.entries;

        } else {

            n->mac_table.multi_overflow = 1;

        }

    }

    return VIRTIO_NET_OK;

}

static int virtio_net_handle_vlan_table(VirtIONet *n, uint8_t cmd,

                                        VirtQueueElement *elem)

{

    uint16_t vid;

    if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(vid)) {

        fprintf(stderr, "virtio-net ctrl invalid vlan command\n");

        return VIRTIO_NET_ERR;

    }

    vid = lduw_le_p(elem->out_sg[1].iov_base);

    if (vid >= MAX_VLAN)

        return VIRTIO_NET_ERR;

    if (cmd == VIRTIO_NET_CTRL_VLAN_ADD)

        n->vlans[vid >> 5] |= (1U << (vid & 0x1f));

    else if (cmd == VIRTIO_NET_CTRL_VLAN_DEL)

        n->vlans[vid >> 5] &= ~(1U << (vid & 0x1f));

    else

        return VIRTIO_NET_ERR;

    return VIRTIO_NET_OK;

}

static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtIONet *n = to_virtio_net(vdev);

    struct virtio_net_ctrl_hdr ctrl;

    virtio_net_ctrl_ack status = VIRTIO_NET_ERR;

    VirtQueueElement elem;

    while (virtqueue_pop(vq, &elem)) {

        if ((elem.in_num < 1) || (elem.out_num < 1)) {

            fprintf(stderr, "virtio-net ctrl missing headers\n");

            exit(1);

        }

        if (elem.out_sg[0].iov_len < sizeof(ctrl) ||

            elem.in_sg[elem.in_num - 1].iov_len < sizeof(status)) {

            fprintf(stderr, "virtio-net ctrl header not in correct element\n");

            exit(1);

        }

        ctrl.class = ldub_p(elem.out_sg[0].iov_base);

        ctrl.cmd = ldub_p(elem.out_sg[0].iov_base + sizeof(ctrl.class));

        if (ctrl.class == VIRTIO_NET_CTRL_RX_MODE)

            status = virtio_net_handle_rx_mode(n, ctrl.cmd, &elem);

        else if (ctrl.class == VIRTIO_NET_CTRL_MAC)

            status = virtio_net_handle_mac(n, ctrl.cmd, &elem);

        else if (ctrl.class == VIRTIO_NET_CTRL_VLAN)

            status = virtio_net_handle_vlan_table(n, ctrl.cmd, &elem);

        stb_p(elem.in_sg[elem.in_num - 1].iov_base, status);

        virtqueue_push(vq, &elem, sizeof(status));

        virtio_notify(vdev, vq);

    }

}

/* RX */

static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtIONet *n = to_virtio_net(vdev);

    qemu_flush_queued_packets(n->vc);

    /* We now have RX buffers, signal to the IO thread to break out of the

     * select to re-poll the tap file descriptor */

    qemu_notify_event();

}

static int do_virtio_net_can_receive(VirtIONet *n, int bufsize)

{

    if (!virtio_queue_ready(n->rx_vq) ||

        !(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))

        return 0;

    if (virtio_queue_empty(n->rx_vq) ||

        (n->mergeable_rx_bufs &&

         !virtqueue_avail_bytes(n->rx_vq, bufsize, 0))) {

        virtio_queue_set_notification(n->rx_vq, 1);

        return 0;

    }

    virtio_queue_set_notification(n->rx_vq, 0);

    return 1;

}

static int virtio_net_can_receive(VLANClientState *vc)

{

    VirtIONet *n = vc->opaque;

    return do_virtio_net_can_receive(n, VIRTIO_NET_MAX_BUFSIZE);

}

static int iov_fill(struct iovec *iov, int iovcnt, const void *buf, int count)

{

    int offset, i;

    offset = i = 0;

    while (offset < count && i < iovcnt) {

        int len = MIN(iov[i].iov_len, count - offset);

        memcpy(iov[i].iov_base, buf + offset, len);

        offset += len;

        i++;

    }

    return offset;

}

static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,

                          const void *buf, size_t size, size_t hdr_len)

{

    struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)iov[0].iov_base;

    int offset = 0;

    hdr->flags = 0;

    hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;

    /* We only ever receive a struct virtio_net_hdr from the tapfd,

     * but we may be passing along a larger header to the guest.

     */

    iov[0].iov_base += hdr_len;

    iov[0].iov_len  -= hdr_len;

    return offset;

}

static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)

{

    static const uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

    static const uint8_t vlan[] = {0x81, 0x00};

    uint8_t *ptr = (uint8_t *)buf;

    int i;

    if (n->promisc)

        return 1;

    if (!memcmp(&ptr[12], vlan, sizeof(vlan))) {

        int vid = be16_to_cpup((uint16_t *)(ptr + 14)) & 0xfff;

        if (!(n->vlans[vid >> 5] & (1U << (vid & 0x1f))))

            return 0;

    }

    if (ptr[0] & 1) { // multicast

        if (!memcmp(ptr, bcast, sizeof(bcast))) {

            return !n->nobcast;

        } else if (n->nomulti) {

            return 0;

        } else if (n->allmulti || n->mac_table.multi_overflow) {

            return 1;

        }

        for (i = n->mac_table.first_multi; i < n->mac_table.in_use; i++) {

            if (!memcmp(ptr, &n->mac_table.macs[i * ETH_ALEN], ETH_ALEN)) {

                return 1;

            }

        }

    } else { // unicast

        if (n->nouni) {

            return 0;

        } else if (n->alluni || n->mac_table.uni_overflow) {

            return 1;

        } else if (!memcmp(ptr, n->mac, ETH_ALEN)) {

            return 1;

        }

        for (i = 0; i < n->mac_table.first_multi; i++) {

            if (!memcmp(ptr, &n->mac_table.macs[i * ETH_ALEN], ETH_ALEN)) {

                return 1;

            }

        }

    }

    return 0;

}

static ssize_t virtio_net_receive(VLANClientState *vc, const uint8_t *buf, size_t size)

{

    VirtIONet *n = vc->opaque;

    struct virtio_net_hdr_mrg_rxbuf *mhdr = NULL;

    size_t hdr_len, offset, i;

    if (!do_virtio_net_can_receive(n, size))

        return 0;

    if (!receive_filter(n, buf, size))

        return size;

    /* hdr_len refers to the header we supply to the guest */

    hdr_len = n->mergeable_rx_bufs ?

        sizeof(struct virtio_net_hdr_mrg_rxbuf) : sizeof(struct virtio_net_hdr);

    offset = i = 0;

    while (offset < size) {

        VirtQueueElement elem;

        int len, total;

        struct iovec sg[VIRTQUEUE_MAX_SIZE];

        len = total = 0;

        if ((i != 0 && !n->mergeable_rx_bufs) ||

            virtqueue_pop(n->rx_vq, &elem) == 0) {

            if (i == 0)

                return -1;

            fprintf(stderr, "virtio-net truncating packet\n");

            exit(1);

        }

        if (elem.in_num < 1) {

            fprintf(stderr, "virtio-net receive queue contains no in buffers\n");

            exit(1);

        }

        if (!n->mergeable_rx_bufs && elem.in_sg[0].iov_len != hdr_len) {

            fprintf(stderr, "virtio-net header not in first element\n");

            exit(1);

        }

        memcpy(&sg, &elem.in_sg[0], sizeof(sg[0]) * elem.in_num);

        if (i == 0) {

            if (n->mergeable_rx_bufs)

                mhdr = (struct virtio_net_hdr_mrg_rxbuf *)sg[0].iov_base;

            offset += receive_header(n, sg, elem.in_num,

                                     buf + offset, size - offset, hdr_len);

            total += hdr_len;

        }

        /* copy in packet.  ugh */

        len = iov_fill(sg, elem.in_num,

                       buf + offset, size - offset);

        total += len;

        /* signal other side */

        virtqueue_fill(n->rx_vq, &elem, total, i++);

        offset += len;

    }

    if (mhdr)

        mhdr->num_buffers = i;

    virtqueue_flush(n->rx_vq, i);

    virtio_notify(&n->vdev, n->rx_vq);

    return size;

}

static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq);

static void virtio_net_tx_complete(VLANClientState *vc, ssize_t len)

{

    VirtIONet *n = vc->opaque;

    virtqueue_push(n->tx_vq, &n->async_tx.elem, n->async_tx.len);

    virtio_notify(&n->vdev, n->tx_vq);

    n->async_tx.elem.out_num = n->async_tx.len = 0;

    virtio_queue_set_notification(n->tx_vq, 1);

    virtio_net_flush_tx(n, n->tx_vq);

}

/* TX */

static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)

{

    VirtQueueElement elem;

    int has_vnet_hdr = 0;

    if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))

        return;

    if (n->async_tx.elem.out_num) {

        virtio_queue_set_notification(n->tx_vq, 0);

        return;

    }

    while (virtqueue_pop(vq, &elem)) {

        ssize_t ret, len = 0;

        unsigned int out_num = elem.out_num;

        struct iovec *out_sg = &elem.out_sg[0];

        unsigned hdr_len;

        /* hdr_len refers to the header received from the guest */

        hdr_len = n->mergeable_rx_bufs ?

            sizeof(struct virtio_net_hdr_mrg_rxbuf) :

            sizeof(struct virtio_net_hdr);

        if (out_num < 1 || out_sg->iov_len != hdr_len) {

            fprintf(stderr, "virtio-net header not in first element\n");

            exit(1);

        }

        /* ignore the header if GSO is not supported */

        if (!has_vnet_hdr) {

            out_num--;

            out_sg++;

            len += hdr_len;

        } else if (n->mergeable_rx_bufs) {

            /* tapfd expects a struct virtio_net_hdr */

            hdr_len -= sizeof(struct virtio_net_hdr);

            out_sg->iov_len -= hdr_len;

            len += hdr_len;

        }

        ret = qemu_sendv_packet_async(n->vc, out_sg, out_num,

                                      virtio_net_tx_complete);

        if (ret == 0) {

            virtio_queue_set_notification(n->tx_vq, 0);

            n->async_tx.elem = elem;

            n->async_tx.len  = len;

            return;

        }

        len += ret;

        virtqueue_push(vq, &elem, len);

        virtio_notify(&n->vdev, vq);

    }

}

static void virtio_net_handle_tx(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtIONet *n = to_virtio_net(vdev);

    if (n->tx_timer_active) {

        virtio_queue_set_notification(vq, 1);

        qemu_del_timer(n->tx_timer);

        n->tx_timer_active = 0;

        virtio_net_flush_tx(n, vq);

    } else {

        qemu_mod_timer(n->tx_timer,

                       qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);

        n->tx_timer_active = 1;

        virtio_queue_set_notification(vq, 0);

    }

}

static void virtio_net_tx_timer(void *opaque)

{

    VirtIONet *n = opaque;

    n->tx_timer_active = 0;

    /* Just in case the driver is not ready on more */

    if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))

        return;

    virtio_queue_set_notification(n->tx_vq, 1);

    virtio_net_flush_tx(n, n->tx_vq);

}

static void virtio_net_save(QEMUFile *f, void *opaque)

{

    VirtIONet *n = opaque;

    virtio_save(&n->vdev, f);

    qemu_put_buffer(f, n->mac, ETH_ALEN);

    qemu_put_be32(f, n->tx_timer_active);

    qemu_put_be32(f, n->mergeable_rx_bufs);

    qemu_put_be16(f, n->status);

    qemu_put_byte(f, n->promisc);

    qemu_put_byte(f, n->allmulti);

    qemu_put_be32(f, n->mac_table.in_use);

    qemu_put_buffer(f, n->mac_table.macs, n->mac_table.in_use * ETH_ALEN);

    qemu_put_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);

    qemu_put_be32(f, 0); /* vnet-hdr placeholder */

    qemu_put_byte(f, n->mac_table.multi_overflow);

    qemu_put_byte(f, n->mac_table.uni_overflow);

    qemu_put_byte(f, n->alluni);

    qemu_put_byte(f, n->nomulti);

    qemu_put_byte(f, n->nouni);

    qemu_put_byte(f, n->nobcast);

}

static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)

{

    VirtIONet *n = opaque;

    int i;

    if (version_id < 2 || version_id > VIRTIO_NET_VM_VERSION)

        return -EINVAL;

    virtio_load(&n->vdev, f);

    qemu_get_buffer(f, n->mac, ETH_ALEN);

    n->tx_timer_active = qemu_get_be32(f);

    n->mergeable_rx_bufs = qemu_get_be32(f);

    if (version_id >= 3)

        n->status = qemu_get_be16(f);

    if (version_id >= 4) {

        if (version_id < 8) {

            n->promisc = qemu_get_be32(f);

            n->allmulti = qemu_get_be32(f);

        } else {

            n->promisc = qemu_get_byte(f);

            n->allmulti = qemu_get_byte(f);

        }

    }

    if (version_id >= 5) {

        n->mac_table.in_use = qemu_get_be32(f);

        /* MAC_TABLE_ENTRIES may be different from the saved image */

        if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {

            qemu_get_buffer(f, n->mac_table.macs,

                            n->mac_table.in_use * ETH_ALEN);

        } else if (n->mac_table.in_use) {

            qemu_fseek(f, n->mac_table.in_use * ETH_ALEN, SEEK_CUR);

            n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1;

            n->mac_table.in_use = 0;

        }

    }

    if (version_id >= 6)

        qemu_get_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);

    if (version_id >= 7 && qemu_get_be32(f)) {

        fprintf(stderr,

                "virtio-net: saved image requires vnet header support\n");

        exit(1);

    }

    if (version_id >= 9) {

        n->mac_table.multi_overflow = qemu_get_byte(f);

        n->mac_table.uni_overflow = qemu_get_byte(f);

    }

    if (version_id >= 10) {

        n->alluni = qemu_get_byte(f);

        n->nomulti = qemu_get_byte(f);

        n->nouni = qemu_get_byte(f);

        n->nobcast = qemu_get_byte(f);

    }

    /* Find the first multicast entry in the saved MAC filter */

    for (i = 0; i < n->mac_table.in_use; i++) {

        if (n->mac_table.macs[i * ETH_ALEN] & 1) {

            break;

        }

    }

    n->mac_table.first_multi = i;

    if (n->tx_timer_active) {

        qemu_mod_timer(n->tx_timer,

                       qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);

    }

    return 0;

}

static void virtio_net_cleanup(VLANClientState *vc)

{

    VirtIONet *n = vc->opaque;

    qemu_purge_queued_packets(vc);

    unregister_savevm("virtio-net", n);

    qemu_free(n->mac_table.macs);

    qemu_free(n->vlans);

    qemu_del_timer(n->tx_timer);

    qemu_free_timer(n->tx_timer);

    virtio_cleanup(&n->vdev);

}

VirtIODevice *virtio_net_init(DeviceState *dev)

{

    VirtIONet *n;

    static int virtio_net_id;

    n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET,

                                        sizeof(struct virtio_net_config),

                                        sizeof(VirtIONet));

    n->vdev.get_config = virtio_net_get_config;

    n->vdev.set_config = virtio_net_set_config;

    n->vdev.get_features = virtio_net_get_features;

    n->vdev.set_features = virtio_net_set_features;

    n->vdev.bad_features = virtio_net_bad_features;

    n->vdev.reset = virtio_net_reset;

    n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);

    n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx);

    n->ctrl_vq = virtio_add_queue(&n->vdev, 64, virtio_net_handle_ctrl);

    qdev_get_macaddr(dev, n->mac);

    n->status = VIRTIO_NET_S_LINK_UP;

    n->vc = qdev_get_vlan_client(dev,

                                 virtio_net_can_receive,

                                 virtio_net_receive, NULL,

                                 virtio_net_cleanup, n);

    n->vc->link_status_changed = virtio_net_set_link_status;

    qemu_format_nic_info_str(n->vc, n->mac);

    n->tx_timer = qemu_new_timer(vm_clock, virtio_net_tx_timer, n);

    n->tx_timer_active = 0;

    n->mergeable_rx_bufs = 0;

    n->promisc = 1; /* for compatibility */

    n->mac_table.macs = qemu_mallocz(MAC_TABLE_ENTRIES * ETH_ALEN);

    n->vlans = qemu_mallocz(MAX_VLAN >> 3);

    if (dev->nd->nvectors == NIC_NVECTORS_UNSPECIFIED)

        n->vdev.nvectors = 3;

    else

        n->vdev.nvectors = dev->nd->nvectors;

    register_savevm("virtio-net", virtio_net_id++, VIRTIO_NET_VM_VERSION,

                    virtio_net_save, virtio_net_load, n);

    return &n->vdev;

}