/*
 * vhost-user.c
 *
 * Copyright (c) 2013 Virtual Open Systems Sarl.
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include "clients.h"
#include "net/vhost_net.h"
#include "net/vhost-user.h"
#include "sysemu/char.h"
#include "qemu/config-file.h"
#include "qemu/error-report.h"

typedef struct VhostUserState {
    NetClientState nc;
    CharDriverState *chr;
    VHostNetState *vhost_net;
} VhostUserState;

typedef struct VhostUserChardevProps {
    bool is_socket;
    bool is_unix;
    bool is_server;
} VhostUserChardevProps;

VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
{
    VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
    assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
    return s->vhost_net;
}

static int vhost_user_running(VhostUserState *s)
{
    return (s->vhost_net) ? 1 : 0;
}

static int vhost_user_start(VhostUserState *s)
{
    VhostNetOptions options;

    if (vhost_user_running(s)) {
        return 0;
    }

    options.backend_type = VHOST_BACKEND_TYPE_USER;
    options.net_backend = &s->nc;
    options.opaque = s->chr;
    options.force = true;

    s->vhost_net = vhost_net_init(&options);

    return vhost_user_running(s) ? 0 : -1;
}

static void vhost_user_stop(VhostUserState *s)
{
    if (vhost_user_running(s)) {
        vhost_net_cleanup(s->vhost_net);
    }

    s->vhost_net = 0;
}

static void vhost_user_cleanup(NetClientState *nc)
{
    VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);

    vhost_user_stop(s);
    qemu_purge_queued_packets(nc);
}

static bool vhost_user_has_vnet_hdr(NetClientState *nc)
{
    assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);

    return true;
}

static bool vhost_user_has_ufo(NetClientState *nc)
{
    assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);

    return true;
}

static NetClientInfo net_vhost_user_info = {
        .type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
        .size = sizeof(VhostUserState),
        .cleanup = vhost_user_cleanup,
        .has_vnet_hdr = vhost_user_has_vnet_hdr,
        .has_ufo = vhost_user_has_ufo,
};

static void net_vhost_link_down(VhostUserState *s, bool link_down)
{
    s->nc.link_down = link_down;

    if (s->nc.peer) {
        s->nc.peer->link_down = link_down;
    }

    if (s->nc.info->link_status_changed) {
        s->nc.info->link_status_changed(&s->nc);
    }

    if (s->nc.peer && s->nc.peer->info->link_status_changed) {
        s->nc.peer->info->link_status_changed(s->nc.peer);
    }
}

static void net_vhost_user_event(void *opaque, int event)
{
    VhostUserState *s = opaque;

    switch (event) {
    case CHR_EVENT_OPENED:
        vhost_user_start(s);
        net_vhost_link_down(s, false);
        error_report("chardev \"%s\" went up", s->chr->label);
        break;
    case CHR_EVENT_CLOSED:
        net_vhost_link_down(s, true);
        vhost_user_stop(s);
        error_report("chardev \"%s\" went down", s->chr->label);
        break;
    }
}

static int net_vhost_user_init(NetClientState *peer, const char *device,
                               const char *name, CharDriverState *chr)
{
    NetClientState *nc;
    VhostUserState *s;

    nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);

    snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user to %s",
             chr->label);

    s = DO_UPCAST(VhostUserState, nc, nc);

    /* We don't provide a receive callback */
    s->nc.receive_disabled = 1;
    s->chr = chr;

    qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);

    return 0;
}

static int net_vhost_chardev_opts(const char *name, const char *value,
                                  void *opaque)
{
    VhostUserChardevProps *props = opaque;

    if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
        props->is_socket = true;
    } else if (strcmp(name, "path") == 0) {
        props->is_unix = true;
    } else if (strcmp(name, "server") == 0) {
        props->is_server = true;
    } else {
        error_report("vhost-user does not support a chardev"
                     " with the following option:\n %s = %s",
                     name, value);
        return -1;
    }
    return 0;
}

static CharDriverState *net_vhost_parse_chardev(const NetdevVhostUserOptions *opts)
{
    CharDriverState *chr = qemu_chr_find(opts->chardev);
    VhostUserChardevProps props;

    if (chr == NULL) {
        error_report("chardev \"%s\" not found", opts->chardev);
        return NULL;
    }

    /* inspect chardev opts */
    memset(&props, 0, sizeof(props));
    if (qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, true) != 0) {
        return NULL;
    }

    if (!props.is_socket || !props.is_unix) {
        error_report("chardev \"%s\" is not a unix socket",
                     opts->chardev);
        return NULL;
    }

    qemu_chr_fe_claim_no_fail(chr);

    return chr;
}

static int net_vhost_check_net(QemuOpts *opts, void *opaque)
{
    const char *name = opaque;
    const char *driver, *netdev;
    const char virtio_name[] = "virtio-net-";

    driver = qemu_opt_get(opts, "driver");
    netdev = qemu_opt_get(opts, "netdev");

    if (!driver || !netdev) {
        return 0;
    }

    if (strcmp(netdev, name) == 0 &&
        strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
        error_report("vhost-user requires frontend driver virtio-net-*");
        return -1;
    }

    return 0;
}

int net_init_vhost_user(const NetClientOptions *opts, const char *name,
                        NetClientState *peer, Error **errp)
{
    /* FIXME error_setg(errp, ...) on failure */
    const NetdevVhostUserOptions *vhost_user_opts;
    CharDriverState *chr;

    assert(opts->kind == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
    vhost_user_opts = opts->vhost_user;

    chr = net_vhost_parse_chardev(vhost_user_opts);
    if (!chr) {
        error_report("No suitable chardev found");
        return -1;
    }

    /* verify net frontend */
    if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
                          (char *)name, true) == -1) {
        return -1;
    }


    return net_vhost_user_init(peer, "vhost_user", name, chr);
}