Archipelago » qemu

/*

 * QEMU System Emulator

 *

 * Copyright (c) 2003-2008 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "config-host.h"

#include "net.h"

#include "net/clients.h"

#include "net/hub.h"

#include "net/slirp.h"

#include "net/util.h"

#include "monitor.h"

#include "qemu-common.h"

#include "qemu_socket.h"

#include "qmp-commands.h"

#include "hw/qdev.h"

#include "iov.h"

#include "qapi-visit.h"

#include "qapi/opts-visitor.h"

#include "qapi/qapi-dealloc-visitor.h"

/* Net bridge is currently not supported for W32. */

#if !defined(_WIN32)

# define CONFIG_NET_BRIDGE

#endif

static QTAILQ_HEAD(, NetClientState) net_clients;

int default_net = 1;

/***********************************************************/

/* network device redirectors */

#if defined(DEBUG_NET)

static void hex_dump(FILE *f, const uint8_t *buf, int size)

{

    int len, i, j, c;

    for(i=0;i<size;i+=16) {

        len = size - i;

        if (len > 16)

            len = 16;

        fprintf(f, "%08x ", i);

        for(j=0;j<16;j++) {

            if (j < len)

                fprintf(f, " %02x", buf[i+j]);

            else

                fprintf(f, "   ");

        }

        fprintf(f, " ");

        for(j=0;j<len;j++) {

            c = buf[i+j];

            if (c < ' ' || c > '~')

                c = '.';

            fprintf(f, "%c", c);

        }

        fprintf(f, "\n");

    }

}

#endif

static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)

{

    const char *p, *p1;

    int len;

    p = *pp;

    p1 = strchr(p, sep);

    if (!p1)

        return -1;

    len = p1 - p;

    p1++;

    if (buf_size > 0) {

        if (len > buf_size - 1)

            len = buf_size - 1;

        memcpy(buf, p, len);

        buf[len] = '\0';

    }

    *pp = p1;

    return 0;

}

int parse_host_port(struct sockaddr_in *saddr, const char *str)

{

    char buf[512];

    struct hostent *he;

    const char *p, *r;

    int port;

    p = str;

    if (get_str_sep(buf, sizeof(buf), &p, ':') < 0)

        return -1;

    saddr->sin_family = AF_INET;

    if (buf[0] == '\0') {

        saddr->sin_addr.s_addr = 0;

    } else {

        if (qemu_isdigit(buf[0])) {

            if (!inet_aton(buf, &saddr->sin_addr))

                return -1;

        } else {

            if ((he = gethostbyname(buf)) == NULL)

                return - 1;

            saddr->sin_addr = *(struct in_addr *)he->h_addr;

        }

    }

    port = strtol(p, (char **)&r, 0);

    if (r == p)

        return -1;

    saddr->sin_port = htons(port);

    return 0;

}

void qemu_format_nic_info_str(NetClientState *nc, uint8_t macaddr[6])

{

    snprintf(nc->info_str, sizeof(nc->info_str),

             "model=%s,macaddr=%02x:%02x:%02x:%02x:%02x:%02x",

             nc->model,

             macaddr[0], macaddr[1], macaddr[2],

             macaddr[3], macaddr[4], macaddr[5]);

}

void qemu_macaddr_default_if_unset(MACAddr *macaddr)

{

    static int index = 0;

    static const MACAddr zero = { .a = { 0,0,0,0,0,0 } };

    if (memcmp(macaddr, &zero, sizeof(zero)) != 0)

        return;

    macaddr->a[0] = 0x52;

    macaddr->a[1] = 0x54;

    macaddr->a[2] = 0x00;

    macaddr->a[3] = 0x12;

    macaddr->a[4] = 0x34;

    macaddr->a[5] = 0x56 + index++;

}

/**

 * Generate a name for net client

 *

 * Only net clients created with the legacy -net option need this.  Naming is

 * mandatory for net clients created with -netdev.

 */

static char *assign_name(NetClientState *nc1, const char *model)

{

    NetClientState *nc;

    char buf[256];

    int id = 0;

    QTAILQ_FOREACH(nc, &net_clients, next) {

        if (nc == nc1) {

            continue;

        }

        /* For compatibility only bump id for net clients on a vlan */

        if (strcmp(nc->model, model) == 0 &&

            net_hub_id_for_client(nc, NULL) == 0) {

            id++;

        }

    }

    snprintf(buf, sizeof(buf), "%s.%d", model, id);

    return g_strdup(buf);

}

NetClientState *qemu_new_net_client(NetClientInfo *info,

                                    NetClientState *peer,

                                    const char *model,

                                    const char *name)

{

    NetClientState *nc;

    assert(info->size >= sizeof(NetClientState));

    nc = g_malloc0(info->size);

    nc->info = info;

    nc->model = g_strdup(model);

    if (name) {

        nc->name = g_strdup(name);

    } else {

        nc->name = assign_name(nc, model);

    }

    if (peer) {

        assert(!peer->peer);

        nc->peer = peer;

        peer->peer = nc;

    }

    QTAILQ_INSERT_TAIL(&net_clients, nc, next);

    nc->send_queue = qemu_new_net_queue(nc);

    return nc;

}

NICState *qemu_new_nic(NetClientInfo *info,

                       NICConf *conf,

                       const char *model,

                       const char *name,

                       void *opaque)

{

    NetClientState *nc;

    NICState *nic;

    assert(info->type == NET_CLIENT_OPTIONS_KIND_NIC);

    assert(info->size >= sizeof(NICState));

    nc = qemu_new_net_client(info, conf->peer, model, name);

    nic = DO_UPCAST(NICState, nc, nc);

    nic->conf = conf;

    nic->opaque = opaque;

    return nic;

}

static void qemu_cleanup_net_client(NetClientState *nc)

{

    QTAILQ_REMOVE(&net_clients, nc, next);

    if (nc->info->cleanup) {

        nc->info->cleanup(nc);

    }

}

static void qemu_free_net_client(NetClientState *nc)

{

    if (nc->send_queue) {

        qemu_del_net_queue(nc->send_queue);

    }

    if (nc->peer) {

        nc->peer->peer = NULL;

    }

    g_free(nc->name);

    g_free(nc->model);

    g_free(nc);

}

void qemu_del_net_client(NetClientState *nc)

{

    /* If there is a peer NIC, delete and cleanup client, but do not free. */

    if (nc->peer && nc->peer->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {

        NICState *nic = DO_UPCAST(NICState, nc, nc->peer);

        if (nic->peer_deleted) {

            return;

        }

        nic->peer_deleted = true;

        /* Let NIC know peer is gone. */

        nc->peer->link_down = true;

        if (nc->peer->info->link_status_changed) {

            nc->peer->info->link_status_changed(nc->peer);

        }

        qemu_cleanup_net_client(nc);

        return;

    }

    /* If this is a peer NIC and peer has already been deleted, free it now. */

    if (nc->peer && nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {

        NICState *nic = DO_UPCAST(NICState, nc, nc);

        if (nic->peer_deleted) {

            qemu_free_net_client(nc->peer);

        }

    }

    qemu_cleanup_net_client(nc);

    qemu_free_net_client(nc);

}

void qemu_foreach_nic(qemu_nic_foreach func, void *opaque)

{

    NetClientState *nc;

    QTAILQ_FOREACH(nc, &net_clients, next) {

        if (nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {

            func(DO_UPCAST(NICState, nc, nc), opaque);

        }

    }

}

int qemu_can_send_packet(NetClientState *sender)

{

    if (!sender->peer) {

        return 1;

    }

    if (sender->peer->receive_disabled) {

        return 0;

    } else if (sender->peer->info->can_receive &&

               !sender->peer->info->can_receive(sender->peer)) {

        return 0;

    }

    return 1;

}

ssize_t qemu_deliver_packet(NetClientState *sender,

                            unsigned flags,

                            const uint8_t *data,

                            size_t size,

                            void *opaque)

{

    NetClientState *nc = opaque;

    ssize_t ret;

    if (nc->link_down) {

        return size;

    }

    if (nc->receive_disabled) {

        return 0;

    }

    if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) {

        ret = nc->info->receive_raw(nc, data, size);

    } else {

        ret = nc->info->receive(nc, data, size);

    }

    if (ret == 0) {

        nc->receive_disabled = 1;

    };

    return ret;

}

void qemu_purge_queued_packets(NetClientState *nc)

{

    if (!nc->peer) {

        return;

    }

    qemu_net_queue_purge(nc->peer->send_queue, nc);

}

void qemu_flush_queued_packets(NetClientState *nc)

{

    nc->receive_disabled = 0;

    if (qemu_net_queue_flush(nc->send_queue)) {

        /* We emptied the queue successfully, signal to the IO thread to repoll

         * the file descriptor (for tap, for example).

         */

        qemu_notify_event();

    }

}

static ssize_t qemu_send_packet_async_with_flags(NetClientState *sender,

                                                 unsigned flags,

                                                 const uint8_t *buf, int size,

                                                 NetPacketSent *sent_cb)

{

    NetQueue *queue;

#ifdef DEBUG_NET

    printf("qemu_send_packet_async:\n");

    hex_dump(stdout, buf, size);

#endif

    if (sender->link_down || !sender->peer) {

        return size;

    }

    queue = sender->peer->send_queue;

    return qemu_net_queue_send(queue, sender, flags, buf, size, sent_cb);

}

ssize_t qemu_send_packet_async(NetClientState *sender,

                               const uint8_t *buf, int size,

                               NetPacketSent *sent_cb)

{

    return qemu_send_packet_async_with_flags(sender, QEMU_NET_PACKET_FLAG_NONE,

                                             buf, size, sent_cb);

}

void qemu_send_packet(NetClientState *nc, const uint8_t *buf, int size)

{

    qemu_send_packet_async(nc, buf, size, NULL);

}

ssize_t qemu_send_packet_raw(NetClientState *nc, const uint8_t *buf, int size)

{

    return qemu_send_packet_async_with_flags(nc, QEMU_NET_PACKET_FLAG_RAW,

                                             buf, size, NULL);

}

static ssize_t nc_sendv_compat(NetClientState *nc, const struct iovec *iov,

                               int iovcnt)

{

    uint8_t buffer[4096];

    size_t offset;

    offset = iov_to_buf(iov, iovcnt, 0, buffer, sizeof(buffer));

    return nc->info->receive(nc, buffer, offset);

}

ssize_t qemu_deliver_packet_iov(NetClientState *sender,

                                unsigned flags,

                                const struct iovec *iov,

                                int iovcnt,

                                void *opaque)

{

    NetClientState *nc = opaque;

    int ret;

    if (nc->link_down) {

        return iov_size(iov, iovcnt);

    }

    if (nc->receive_disabled) {

        return 0;

    }

    if (nc->info->receive_iov) {

        ret = nc->info->receive_iov(nc, iov, iovcnt);

    } else {

        ret = nc_sendv_compat(nc, iov, iovcnt);

    }

    if (ret == 0) {

        nc->receive_disabled = 1;

    }

    return ret;

}

ssize_t qemu_sendv_packet_async(NetClientState *sender,

                                const struct iovec *iov, int iovcnt,

                                NetPacketSent *sent_cb)

{

    NetQueue *queue;

    if (sender->link_down || !sender->peer) {

        return iov_size(iov, iovcnt);

    }

    queue = sender->peer->send_queue;

    return qemu_net_queue_send_iov(queue, sender,

                                   QEMU_NET_PACKET_FLAG_NONE,

                                   iov, iovcnt, sent_cb);

}

ssize_t

qemu_sendv_packet(NetClientState *nc, const struct iovec *iov, int iovcnt)

{

    return qemu_sendv_packet_async(nc, iov, iovcnt, NULL);

}

NetClientState *qemu_find_netdev(const char *id)

{

    NetClientState *nc;

    QTAILQ_FOREACH(nc, &net_clients, next) {

        if (nc->info->type == NET_CLIENT_OPTIONS_KIND_NIC)

            continue;

        if (!strcmp(nc->name, id)) {

            return nc;

        }

    }

    return NULL;

}

static int nic_get_free_idx(void)

{

    int index;

    for (index = 0; index < MAX_NICS; index++)

        if (!nd_table[index].used)

            return index;

    return -1;

}

int qemu_show_nic_models(const char *arg, const char *const *models)

{

    int i;

    if (!arg || !is_help_option(arg)) {

        return 0;

    }

    fprintf(stderr, "qemu: Supported NIC models: ");

    for (i = 0 ; models[i]; i++)

        fprintf(stderr, "%s%c", models[i], models[i+1] ? ',' : '\n');

    return 1;

}

void qemu_check_nic_model(NICInfo *nd, const char *model)

{

    const char *models[2];

    models[0] = model;

    models[1] = NULL;

    if (qemu_show_nic_models(nd->model, models))

        exit(0);

    if (qemu_find_nic_model(nd, models, model) < 0)

        exit(1);

}

int qemu_find_nic_model(NICInfo *nd, const char * const *models,

                        const char *default_model)

{

    int i;

    if (!nd->model)

        nd->model = g_strdup(default_model);

    for (i = 0 ; models[i]; i++) {

        if (strcmp(nd->model, models[i]) == 0)

            return i;

    }

    error_report("Unsupported NIC model: %s", nd->model);

    return -1;

}

static int net_init_nic(const NetClientOptions *opts, const char *name,

                        NetClientState *peer)

{

    int idx;

    NICInfo *nd;

    const NetLegacyNicOptions *nic;

    assert(opts->kind == NET_CLIENT_OPTIONS_KIND_NIC);

    nic = opts->nic;

    idx = nic_get_free_idx();

    if (idx == -1 || nb_nics >= MAX_NICS) {

        error_report("Too Many NICs");

        return -1;

    }

    nd = &nd_table[idx];

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

    if (nic->has_netdev) {

        nd->netdev = qemu_find_netdev(nic->netdev);

        if (!nd->netdev) {

            error_report("netdev '%s' not found", nic->netdev);

            return -1;

        }

    } else {

        assert(peer);

        nd->netdev = peer;

    }

    if (name) {

        nd->name = g_strdup(name);

    }

    if (nic->has_model) {

        nd->model = g_strdup(nic->model);

    }

    if (nic->has_addr) {

        nd->devaddr = g_strdup(nic->addr);

    }

    if (nic->has_macaddr &&

        net_parse_macaddr(nd->macaddr.a, nic->macaddr) < 0) {

        error_report("invalid syntax for ethernet address");

        return -1;

    }

    qemu_macaddr_default_if_unset(&nd->macaddr);

    if (nic->has_vectors) {

        if (nic->vectors > 0x7ffffff) {

            error_report("invalid # of vectors: %"PRIu32, nic->vectors);

            return -1;

        }

        nd->nvectors = nic->vectors;

    } else {

        nd->nvectors = DEV_NVECTORS_UNSPECIFIED;

    }

    nd->used = 1;

    nb_nics++;

    return idx;

}

static int (* const net_client_init_fun[NET_CLIENT_OPTIONS_KIND_MAX])(

    const NetClientOptions *opts,

    const char *name,

    NetClientState *peer) = {

        [NET_CLIENT_OPTIONS_KIND_NIC]       = net_init_nic,

#ifdef CONFIG_SLIRP

        [NET_CLIENT_OPTIONS_KIND_USER]      = net_init_slirp,

#endif

        [NET_CLIENT_OPTIONS_KIND_TAP]       = net_init_tap,

        [NET_CLIENT_OPTIONS_KIND_SOCKET]    = net_init_socket,

#ifdef CONFIG_VDE

        [NET_CLIENT_OPTIONS_KIND_VDE]       = net_init_vde,

#endif

        [NET_CLIENT_OPTIONS_KIND_DUMP]      = net_init_dump,

#ifdef CONFIG_NET_BRIDGE

        [NET_CLIENT_OPTIONS_KIND_BRIDGE]    = net_init_bridge,

#endif

        [NET_CLIENT_OPTIONS_KIND_HUBPORT]   = net_init_hubport,

};

static int net_client_init1(const void *object, int is_netdev, Error **errp)

{

    union {

        const Netdev    *netdev;

        const NetLegacy *net;

    } u;

    const NetClientOptions *opts;

    const char *name;

    if (is_netdev) {

        u.netdev = object;

        opts = u.netdev->opts;

        name = u.netdev->id;

        switch (opts->kind) {

#ifdef CONFIG_SLIRP

        case NET_CLIENT_OPTIONS_KIND_USER:

#endif

        case NET_CLIENT_OPTIONS_KIND_TAP:

        case NET_CLIENT_OPTIONS_KIND_SOCKET:

#ifdef CONFIG_VDE

        case NET_CLIENT_OPTIONS_KIND_VDE:

#endif

#ifdef CONFIG_NET_BRIDGE

        case NET_CLIENT_OPTIONS_KIND_BRIDGE:

#endif

        case NET_CLIENT_OPTIONS_KIND_HUBPORT:

            break;

        default:

            error_set(errp, QERR_INVALID_PARAMETER_VALUE, "type",

                      "a netdev backend type");

            return -1;

        }

    } else {

        u.net = object;

        opts = u.net->opts;

        /* missing optional values have been initialized to "all bits zero" */

        name = u.net->has_id ? u.net->id : u.net->name;

    }

    if (net_client_init_fun[opts->kind]) {

        NetClientState *peer = NULL;

        /* Do not add to a vlan if it's a -netdev or a nic with a netdev=

         * parameter. */

        if (!is_netdev &&

            (opts->kind != NET_CLIENT_OPTIONS_KIND_NIC ||

             !opts->nic->has_netdev)) {

            peer = net_hub_add_port(u.net->has_vlan ? u.net->vlan : 0, NULL);

        }

        if (net_client_init_fun[opts->kind](opts, name, peer) < 0) {

            /* TODO push error reporting into init() methods */

            error_set(errp, QERR_DEVICE_INIT_FAILED,

                      NetClientOptionsKind_lookup[opts->kind]);

            return -1;

        }

    }

    return 0;

}

static void net_visit(Visitor *v, int is_netdev, void **object, Error **errp)

{

    if (is_netdev) {

        visit_type_Netdev(v, (Netdev **)object, NULL, errp);

    } else {

        visit_type_NetLegacy(v, (NetLegacy **)object, NULL, errp);

    }

}

int net_client_init(QemuOpts *opts, int is_netdev, Error **errp)

{

    void *object = NULL;

    Error *err = NULL;

    int ret = -1;

    {

        OptsVisitor *ov = opts_visitor_new(opts);

        net_visit(opts_get_visitor(ov), is_netdev, &object, &err);

        opts_visitor_cleanup(ov);

    }

    if (!err) {

        ret = net_client_init1(object, is_netdev, &err);

    }

    if (object) {

        QapiDeallocVisitor *dv = qapi_dealloc_visitor_new();

        net_visit(qapi_dealloc_get_visitor(dv), is_netdev, &object, NULL);

        qapi_dealloc_visitor_cleanup(dv);

    }

    error_propagate(errp, err);

    return ret;

}

static int net_host_check_device(const char *device)

{

    int i;

    const char *valid_param_list[] = { "tap", "socket", "dump"

#ifdef CONFIG_NET_BRIDGE

                                       , "bridge"

#endif

#ifdef CONFIG_SLIRP

                                       ,"user"

#endif

#ifdef CONFIG_VDE

                                       ,"vde"

#endif

    };

    for (i = 0; i < sizeof(valid_param_list) / sizeof(char *); i++) {

        if (!strncmp(valid_param_list[i], device,

                     strlen(valid_param_list[i])))

            return 1;

    }

    return 0;

}

void net_host_device_add(Monitor *mon, const QDict *qdict)

{

    const char *device = qdict_get_str(qdict, "device");

    const char *opts_str = qdict_get_try_str(qdict, "opts");

    Error *local_err = NULL;

    QemuOpts *opts;

    if (!net_host_check_device(device)) {

        monitor_printf(mon, "invalid host network device %s\n", device);

        return;

    }

    opts = qemu_opts_parse(qemu_find_opts("net"), opts_str ? opts_str : "", 0);

    if (!opts) {

        return;

    }

    qemu_opt_set(opts, "type", device);

    net_client_init(opts, 0, &local_err);

    if (error_is_set(&local_err)) {

        qerror_report_err(local_err);

        error_free(local_err);

        monitor_printf(mon, "adding host network device %s failed\n", device);

    }

}

void net_host_device_remove(Monitor *mon, const QDict *qdict)

{

    NetClientState *nc;

    int vlan_id = qdict_get_int(qdict, "vlan_id");

    const char *device = qdict_get_str(qdict, "device");

    nc = net_hub_find_client_by_name(vlan_id, device);

    if (!nc) {

        return;

    }

    if (!net_host_check_device(nc->model)) {

        monitor_printf(mon, "invalid host network device %s\n", device);

        return;

    }

    qemu_del_net_client(nc);

}

void netdev_add(QemuOpts *opts, Error **errp)

{

    net_client_init(opts, 1, errp);

}

int qmp_netdev_add(Monitor *mon, const QDict *qdict, QObject **ret)

{

    Error *local_err = NULL;

    QemuOptsList *opts_list;

    QemuOpts *opts;

    opts_list = qemu_find_opts_err("netdev", &local_err);

    if (error_is_set(&local_err)) {

        goto exit_err;

    }

    opts = qemu_opts_from_qdict(opts_list, qdict, &local_err);

    if (error_is_set(&local_err)) {

        goto exit_err;

    }

    netdev_add(opts, &local_err);

    if (error_is_set(&local_err)) {

        qemu_opts_del(opts);

        goto exit_err;

    }

    return 0;

exit_err:

    qerror_report_err(local_err);

    error_free(local_err);

    return -1;

}

void qmp_netdev_del(const char *id, Error **errp)

{

    NetClientState *nc;

    QemuOpts *opts;

    nc = qemu_find_netdev(id);

    if (!nc) {

        error_set(errp, QERR_DEVICE_NOT_FOUND, id);

        return;

    }

    opts = qemu_opts_find(qemu_find_opts_err("netdev", NULL), id);

    if (!opts) {

        error_setg(errp, "Device '%s' is not a netdev", id);

        return;

    }

    qemu_del_net_client(nc);

    qemu_opts_del(opts);

}

void print_net_client(Monitor *mon, NetClientState *nc)

{

    monitor_printf(mon, "%s: type=%s,%s\n", nc->name,

                   NetClientOptionsKind_lookup[nc->info->type], nc->info_str);

}

void do_info_network(Monitor *mon)

{

    NetClientState *nc, *peer;

    NetClientOptionsKind type;

    net_hub_info(mon);

    QTAILQ_FOREACH(nc, &net_clients, next) {

        peer = nc->peer;

        type = nc->info->type;

        /* Skip if already printed in hub info */

        if (net_hub_id_for_client(nc, NULL) == 0) {

            continue;

        }

        if (!peer || type == NET_CLIENT_OPTIONS_KIND_NIC) {

            print_net_client(mon, nc);

        } /* else it's a netdev connected to a NIC, printed with the NIC */

        if (peer && type == NET_CLIENT_OPTIONS_KIND_NIC) {

            monitor_printf(mon, " \\ ");

            print_net_client(mon, peer);

        }

    }

}

void qmp_set_link(const char *name, bool up, Error **errp)

{

    NetClientState *nc = NULL;

    QTAILQ_FOREACH(nc, &net_clients, next) {

        if (!strcmp(nc->name, name)) {

            goto done;

        }

    }

done:

    if (!nc) {

        error_set(errp, QERR_DEVICE_NOT_FOUND, name);

        return;

    }

    nc->link_down = !up;