/*

 * 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"

typedef struct VirtIONet

{

    VirtIODevice vdev;

    uint8_t mac[6];

    VirtQueue *rx_vq;

    VirtQueue *tx_vq;

    VLANClientState *vc;

    QEMUTimer *tx_timer;

    int tx_timer_active;

    int mergeable_rx_bufs;

} 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_update_config(VirtIODevice *vdev, uint8_t *config)

{

    VirtIONet *n = to_virtio_net(vdev);

    struct virtio_net_config netcfg;

    memcpy(netcfg.mac, n->mac, 6);

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

}

static uint32_t virtio_net_get_features(VirtIODevice *vdev)

{

    uint32_t features = (1 << VIRTIO_NET_F_MAC);

    return features;

}

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));

}

/* RX */

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

{

}

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(void *opaque)

{

    VirtIONet *n = 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 = 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 void virtio_net_receive(void *opaque, const uint8_t *buf, int size)

{

    VirtIONet *n = opaque;

    struct virtio_net_hdr_mrg_rxbuf *mhdr = NULL;

    size_t hdr_len, offset, i;

    if (!do_virtio_net_can_receive(n, size))

        return;

    /* 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;

            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);

}

/* 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;

    while (virtqueue_pop(vq, &elem)) {

        ssize_t 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;

        }

        len += qemu_sendv_packet(n->vc, out_sg, out_num);

        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, 6);

    qemu_put_be32(f, n->tx_timer_active);

}

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

{

    VirtIONet *n = opaque;

    if (version_id != 1)

        return -EINVAL;

    virtio_load(&n->vdev, f);

    qemu_get_buffer(f, n->mac, 6);

    n->tx_timer_active = qemu_get_be32(f);

    if (n->tx_timer_active) {

        qemu_mod_timer(n->tx_timer,

                       qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);

    }

    return 0;

}

void virtio_net_init(VirtIOBindFn bind, void *bind_arg, NICInfo *nd)

{

    VirtIONet *n;

    static int virtio_net_id;

    n = (VirtIONet *)bind(bind_arg, "virtio-net", 0, VIRTIO_ID_NET,

                          6, sizeof(VirtIONet));

    if (!n)

        return;

    n->vdev.get_config = virtio_net_update_config;

    n->vdev.get_features = virtio_net_get_features;

    n->vdev.set_features = virtio_net_set_features;

    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);

    memcpy(n->mac, nd->macaddr, 6);

    n->vc = qemu_new_vlan_client(nd->vlan, virtio_net_receive,

                                 virtio_net_can_receive, n);

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

    n->tx_timer_active = 0;

    n->mergeable_rx_bufs = 0;

    register_savevm("virtio-net", virtio_net_id++, 1,

                    virtio_net_save, virtio_net_load, n);

}