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-rw-r--r--net/passt.c753
1 files changed, 753 insertions, 0 deletions
diff --git a/net/passt.c b/net/passt.c
new file mode 100644
index 0000000000..6f616ba3c2
--- /dev/null
+++ b/net/passt.c
@@ -0,0 +1,753 @@
+/*
+ * passt network backend
+ *
+ * Copyright Red Hat
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include "qemu/osdep.h"
+#include <glib/gstdio.h>
+#include "qemu/error-report.h"
+#include <gio/gio.h>
+#include "net/net.h"
+#include "clients.h"
+#include "qapi/error.h"
+#include "io/net-listener.h"
+#include "chardev/char-fe.h"
+#include "net/vhost_net.h"
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-user.h"
+#include "standard-headers/linux/virtio_net.h"
+#include "stream_data.h"
+
+#ifdef CONFIG_VHOST_USER
+static const int user_feature_bits[] = {
+    VIRTIO_F_NOTIFY_ON_EMPTY,
+    VIRTIO_F_NOTIFICATION_DATA,
+    VIRTIO_RING_F_INDIRECT_DESC,
+    VIRTIO_RING_F_EVENT_IDX,
+
+    VIRTIO_F_ANY_LAYOUT,
+    VIRTIO_F_VERSION_1,
+    VIRTIO_NET_F_CSUM,
+    VIRTIO_NET_F_GUEST_CSUM,
+    VIRTIO_NET_F_GSO,
+    VIRTIO_NET_F_GUEST_TSO4,
+    VIRTIO_NET_F_GUEST_TSO6,
+    VIRTIO_NET_F_GUEST_ECN,
+    VIRTIO_NET_F_GUEST_UFO,
+    VIRTIO_NET_F_HOST_TSO4,
+    VIRTIO_NET_F_HOST_TSO6,
+    VIRTIO_NET_F_HOST_ECN,
+    VIRTIO_NET_F_HOST_UFO,
+    VIRTIO_NET_F_MRG_RXBUF,
+    VIRTIO_NET_F_MTU,
+    VIRTIO_F_IOMMU_PLATFORM,
+    VIRTIO_F_RING_PACKED,
+    VIRTIO_F_RING_RESET,
+    VIRTIO_F_IN_ORDER,
+    VIRTIO_NET_F_RSS,
+    VIRTIO_NET_F_RSC_EXT,
+    VIRTIO_NET_F_HASH_REPORT,
+    VIRTIO_NET_F_GUEST_USO4,
+    VIRTIO_NET_F_GUEST_USO6,
+    VIRTIO_NET_F_HOST_USO,
+
+    /* This bit implies RARP isn't sent by QEMU out of band */
+    VIRTIO_NET_F_GUEST_ANNOUNCE,
+
+    VIRTIO_NET_F_MQ,
+
+    VHOST_INVALID_FEATURE_BIT
+};
+#endif
+
+typedef struct NetPasstState {
+    NetStreamData data;
+    GPtrArray *args;
+    gchar *pidfile;
+    pid_t pid;
+#ifdef CONFIG_VHOST_USER
+    /* vhost user */
+    VhostUserState *vhost_user;
+    VHostNetState *vhost_net;
+    CharBackend vhost_chr;
+    guint vhost_watch;
+    uint64_t acked_features;
+    bool started;
+#endif
+} NetPasstState;
+
+static int net_passt_stream_start(NetPasstState *s, Error **errp);
+
+static void net_passt_cleanup(NetClientState *nc)
+{
+    NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+#ifdef CONFIG_VHOST_USER
+    if (s->vhost_net) {
+        vhost_net_cleanup(s->vhost_net);
+        g_free(s->vhost_net);
+        s->vhost_net = NULL;
+    }
+    if (s->vhost_watch) {
+        g_source_remove(s->vhost_watch);
+        s->vhost_watch = 0;
+    }
+    qemu_chr_fe_deinit(&s->vhost_chr, true);
+    if (s->vhost_user) {
+        vhost_user_cleanup(s->vhost_user);
+        g_free(s->vhost_user);
+        s->vhost_user = NULL;
+    }
+#endif
+
+    kill(s->pid, SIGTERM);
+    g_remove(s->pidfile);
+    g_free(s->pidfile);
+    g_ptr_array_free(s->args, TRUE);
+}
+
+static ssize_t net_passt_receive(NetClientState *nc, const uint8_t *buf,
+                                  size_t size)
+{
+    NetStreamData *d = DO_UPCAST(NetStreamData, nc, nc);
+
+    return net_stream_data_receive(d, buf, size);
+}
+
+static gboolean net_passt_send(QIOChannel *ioc, GIOCondition condition,
+                                gpointer data)
+{
+    if (net_stream_data_send(ioc, condition, data) == G_SOURCE_REMOVE) {
+        NetPasstState *s = DO_UPCAST(NetPasstState, data, data);
+        Error *error;
+
+        /* we need to restart passt */
+        kill(s->pid, SIGTERM);
+        if (net_passt_stream_start(s, &error) == -1) {
+            error_report_err(error);
+        }
+
+        return G_SOURCE_REMOVE;
+    }
+
+    return G_SOURCE_CONTINUE;
+}
+
+#ifdef CONFIG_VHOST_USER
+static int passt_set_vnet_endianness(NetClientState *nc, bool enable)
+{
+    assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+    return 0;
+}
+
+static bool passt_has_vnet_hdr(NetClientState *nc)
+{
+    NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+    assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+    return s->vhost_user != NULL;
+}
+
+static bool passt_has_ufo(NetClientState *nc)
+{
+    NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+    assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+    return s->vhost_user != NULL;
+}
+
+static bool passt_check_peer_type(NetClientState *nc, ObjectClass *oc,
+                                             Error **errp)
+{
+    NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+    const char *driver = object_class_get_name(oc);
+
+    assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+    if (s->vhost_user == NULL) {
+        return true;
+    }
+
+    if (!g_str_has_prefix(driver, "virtio-net-")) {
+        error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
+        return false;
+    }
+
+    return true;
+}
+
+static struct vhost_net *passt_get_vhost_net(NetClientState *nc)
+{
+    NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+    assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+    return s->vhost_net;
+}
+
+static uint64_t passt_get_acked_features(NetClientState *nc)
+{
+    NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+    assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+    return s->acked_features;
+}
+
+static void passt_save_acked_features(NetClientState *nc)
+{
+    NetPasstState *s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+    assert(nc->info->type == NET_CLIENT_DRIVER_PASST);
+
+    if (s->vhost_net) {
+        uint64_t features = vhost_net_get_acked_features(s->vhost_net);
+        if (features) {
+            s->acked_features = features;
+        }
+    }
+}
+#endif
+
+static NetClientInfo net_passt_info = {
+    .type = NET_CLIENT_DRIVER_PASST,
+    .size = sizeof(NetPasstState),
+    .receive = net_passt_receive,
+    .cleanup = net_passt_cleanup,
+#ifdef CONFIG_VHOST_USER
+    .has_vnet_hdr = passt_has_vnet_hdr,
+    .has_ufo = passt_has_ufo,
+    .set_vnet_be = passt_set_vnet_endianness,
+    .set_vnet_le = passt_set_vnet_endianness,
+    .check_peer_type = passt_check_peer_type,
+    .get_vhost_net = passt_get_vhost_net,
+#endif
+};
+
+static void net_passt_client_connected(QIOTask *task, gpointer opaque)
+{
+    NetPasstState *s = opaque;
+
+    if (net_stream_data_client_connected(task, &s->data) == 0) {
+        qemu_set_info_str(&s->data.nc, "stream,connected to pid %d", s->pid);
+    }
+}
+
+static int net_passt_start_daemon(NetPasstState *s, int sock, Error **errp)
+{
+    g_autoptr(GSubprocess) daemon = NULL;
+    g_autofree gchar *contents = NULL;
+    g_autoptr(GError) error = NULL;
+    GSubprocessLauncher *launcher;
+
+    qemu_set_info_str(&s->data.nc, "launching passt");
+
+    launcher = g_subprocess_launcher_new(G_SUBPROCESS_FLAGS_NONE);
+    g_subprocess_launcher_take_fd(launcher, sock, 3);
+
+    daemon =  g_subprocess_launcher_spawnv(launcher,
+                                           (const gchar *const *)s->args->pdata,
+                                           &error);
+    g_object_unref(launcher);
+
+    if (!daemon) {
+        error_setg(errp, "Error creating daemon: %s", error->message);
+        return -1;
+    }
+
+    if (!g_subprocess_wait(daemon, NULL, &error)) {
+        error_setg(errp, "Error waiting for daemon: %s", error->message);
+        return -1;
+    }
+
+    if (g_subprocess_get_if_exited(daemon) &&
+        g_subprocess_get_exit_status(daemon)) {
+        return -1;
+    }
+
+    if (!g_file_get_contents(s->pidfile, &contents, NULL, &error)) {
+        error_setg(errp, "Cannot read passt pid: %s", error->message);
+        return -1;
+    }
+
+    s->pid = (pid_t)g_ascii_strtoll(contents, NULL, 10);
+    if (s->pid <= 0) {
+        error_setg(errp, "File '%s' did not contain a valid PID.", s->pidfile);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int net_passt_stream_start(NetPasstState *s, Error **errp)
+{
+    QIOChannelSocket *sioc;
+    SocketAddress *addr;
+    int sv[2];
+
+    if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
+        error_setg_errno(errp, errno, "socketpair() failed");
+        return -1;
+    }
+
+    /* connect to passt */
+    qemu_set_info_str(&s->data.nc, "connecting to passt");
+
+    /* create socket channel */
+    sioc = qio_channel_socket_new();
+    s->data.ioc = QIO_CHANNEL(sioc);
+    s->data.nc.link_down = true;
+    s->data.send = net_passt_send;
+
+    addr = g_new0(SocketAddress, 1);
+    addr->type = SOCKET_ADDRESS_TYPE_FD;
+    addr->u.fd.str = g_strdup_printf("%d", sv[0]);
+
+    qio_channel_socket_connect_async(sioc, addr,
+                                     net_passt_client_connected, s,
+                                     NULL, NULL);
+
+    qapi_free_SocketAddress(addr);
+
+    /* start passt */
+    if (net_passt_start_daemon(s, sv[1], errp) == -1) {
+        close(sv[0]);
+        close(sv[1]);
+        return -1;
+    }
+    close(sv[1]);
+
+    return 0;
+}
+
+#ifdef CONFIG_VHOST_USER
+static gboolean passt_vhost_user_watch(void *do_not_use, GIOCondition cond,
+                                       void *opaque)
+{
+    NetPasstState *s = opaque;
+
+    qemu_chr_fe_disconnect(&s->vhost_chr);
+
+    return G_SOURCE_CONTINUE;
+}
+
+static void passt_vhost_user_event(void *opaque, QEMUChrEvent event);
+
+static void chr_closed_bh(void *opaque)
+{
+    NetPasstState *s = opaque;
+
+    passt_save_acked_features(&s->data.nc);
+
+    net_client_set_link(&(NetClientState *){ &s->data.nc }, 1, false);
+
+    qemu_chr_fe_set_handlers(&s->vhost_chr, NULL, NULL, passt_vhost_user_event,
+                             NULL, s, NULL, true);
+}
+
+static void passt_vhost_user_stop(NetPasstState *s)
+{
+    passt_save_acked_features(&s->data.nc);
+    vhost_net_cleanup(s->vhost_net);
+}
+
+static int passt_vhost_user_start(NetPasstState *s, VhostUserState *be)
+{
+    struct vhost_net *net = NULL;
+    VhostNetOptions options;
+
+    options.backend_type = VHOST_BACKEND_TYPE_USER;
+    options.net_backend = &s->data.nc;
+    options.opaque = be;
+    options.busyloop_timeout = 0;
+    options.nvqs = 2;
+    options.feature_bits = user_feature_bits;
+    options.max_tx_queue_size = VIRTQUEUE_MAX_SIZE;
+    options.get_acked_features = passt_get_acked_features;
+    options.save_acked_features = passt_save_acked_features;
+    options.is_vhost_user = true;
+
+    net = vhost_net_init(&options);
+    if (!net) {
+        error_report("failed to init passt vhost_net");
+        goto err;
+    }
+
+    if (s->vhost_net) {
+        vhost_net_cleanup(s->vhost_net);
+        g_free(s->vhost_net);
+    }
+    s->vhost_net = net;
+
+    return 0;
+err:
+    if (net) {
+        vhost_net_cleanup(net);
+        g_free(net);
+    }
+    passt_vhost_user_stop(s);
+    return -1;
+}
+
+static void passt_vhost_user_event(void *opaque, QEMUChrEvent event)
+{
+    NetPasstState *s = opaque;
+    Error *err = NULL;
+
+    switch (event) {
+    case CHR_EVENT_OPENED:
+        if (passt_vhost_user_start(s, s->vhost_user) < 0) {
+            qemu_chr_fe_disconnect(&s->vhost_chr);
+            return;
+        }
+        s->vhost_watch = qemu_chr_fe_add_watch(&s->vhost_chr, G_IO_HUP,
+                                               passt_vhost_user_watch, s);
+        net_client_set_link(&(NetClientState *){ &s->data.nc }, 1, true);
+        s->started = true;
+        break;
+    case CHR_EVENT_CLOSED:
+        if (s->vhost_watch) {
+            AioContext *ctx = qemu_get_current_aio_context();
+
+            g_source_remove(s->vhost_watch);
+            s->vhost_watch = 0;
+            qemu_chr_fe_set_handlers(&s->vhost_chr, NULL, NULL,  NULL, NULL,
+                                     NULL, NULL, false);
+
+            aio_bh_schedule_oneshot(ctx, chr_closed_bh, s);
+        }
+        break;
+    case CHR_EVENT_BREAK:
+    case CHR_EVENT_MUX_IN:
+    case CHR_EVENT_MUX_OUT:
+        /* Ignore */
+        break;
+    }
+
+    if (err) {
+        error_report_err(err);
+    }
+}
+
+static int net_passt_vhost_user_init(NetPasstState *s, Error **errp)
+{
+    Chardev *chr;
+    int sv[2];
+
+    if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
+        error_setg_errno(errp, errno, "socketpair() failed");
+        return -1;
+    }
+
+    /* connect to passt */
+    qemu_set_info_str(&s->data.nc, "connecting to passt");
+
+    /* create chardev */
+
+    chr = CHARDEV(object_new(TYPE_CHARDEV_SOCKET));
+    if (!chr || qemu_chr_add_client(chr, sv[0]) == -1) {
+        object_unref(OBJECT(chr));
+        error_setg(errp, "Failed to make socket chardev");
+        goto err;
+    }
+
+    s->vhost_user = g_new0(struct VhostUserState, 1);
+    if (!qemu_chr_fe_init(&s->vhost_chr, chr, errp) ||
+        !vhost_user_init(s->vhost_user, &s->vhost_chr, errp)) {
+        goto err;
+    }
+
+    /* start passt */
+    if (net_passt_start_daemon(s, sv[1], errp) == -1) {
+        goto err;
+    }
+
+    do {
+        if (qemu_chr_fe_wait_connected(&s->vhost_chr, errp) < 0) {
+            goto err;
+        }
+
+        qemu_chr_fe_set_handlers(&s->vhost_chr, NULL, NULL,
+                                 passt_vhost_user_event, NULL, s, NULL,
+                                 true);
+    } while (!s->started);
+
+    qemu_set_info_str(&s->data.nc, "vhost-user,connected to pid %d", s->pid);
+
+    close(sv[1]);
+    return 0;
+err:
+    close(sv[0]);
+    close(sv[1]);
+
+    return -1;
+}
+#else
+static int net_passt_vhost_user_init(NetPasstState *s, Error **errp)
+{
+    error_setg(errp, "vhost-user support has not been built");
+
+    return -1;
+}
+#endif
+
+static GPtrArray *net_passt_decode_args(const NetDevPasstOptions *passt,
+                                        gchar *pidfile, Error **errp)
+{
+    GPtrArray *args = g_ptr_array_new_with_free_func(g_free);
+
+    if (passt->path) {
+        g_ptr_array_add(args, g_strdup(passt->path));
+    } else {
+        g_ptr_array_add(args, g_strdup("passt"));
+    }
+
+    if (passt->has_vhost_user && passt->vhost_user) {
+        g_ptr_array_add(args, g_strdup("--vhost-user"));
+    }
+
+    /* by default, be quiet */
+    if (!passt->has_quiet || passt->quiet) {
+        g_ptr_array_add(args, g_strdup("--quiet"));
+    }
+
+    if (passt->has_mtu) {
+        g_ptr_array_add(args, g_strdup("--mtu"));
+        g_ptr_array_add(args, g_strdup_printf("%"PRId64, passt->mtu));
+    }
+
+    if (passt->address) {
+        g_ptr_array_add(args, g_strdup("--address"));
+        g_ptr_array_add(args, g_strdup(passt->address));
+    }
+
+    if (passt->netmask) {
+        g_ptr_array_add(args, g_strdup("--netmask"));
+        g_ptr_array_add(args, g_strdup(passt->netmask));
+    }
+
+    if (passt->mac) {
+        g_ptr_array_add(args, g_strdup("--mac-addr"));
+        g_ptr_array_add(args, g_strdup(passt->mac));
+    }
+
+    if (passt->gateway) {
+        g_ptr_array_add(args, g_strdup("--gateway"));
+        g_ptr_array_add(args, g_strdup(passt->gateway));
+    }
+
+    if (passt->interface) {
+        g_ptr_array_add(args, g_strdup("--interface"));
+        g_ptr_array_add(args, g_strdup(passt->interface));
+    }
+
+    if (passt->outbound) {
+        g_ptr_array_add(args, g_strdup("--outbound"));
+        g_ptr_array_add(args, g_strdup(passt->outbound));
+    }
+
+    if (passt->outbound_if4) {
+        g_ptr_array_add(args, g_strdup("--outbound-if4"));
+        g_ptr_array_add(args, g_strdup(passt->outbound_if4));
+    }
+
+    if (passt->outbound_if6) {
+        g_ptr_array_add(args, g_strdup("--outbound-if6"));
+        g_ptr_array_add(args, g_strdup(passt->outbound_if6));
+    }
+
+    if (passt->dns) {
+        g_ptr_array_add(args, g_strdup("--dns"));
+        g_ptr_array_add(args, g_strdup(passt->dns));
+    }
+    if (passt->fqdn) {
+        g_ptr_array_add(args, g_strdup("--fqdn"));
+        g_ptr_array_add(args, g_strdup(passt->fqdn));
+    }
+
+    if (passt->has_dhcp_dns && !passt->dhcp_dns) {
+        g_ptr_array_add(args, g_strdup("--no-dhcp-dns"));
+    }
+
+    if (passt->has_dhcp_search && !passt->dhcp_search) {
+        g_ptr_array_add(args, g_strdup("--no-dhcp-search"));
+    }
+
+    if (passt->map_host_loopback) {
+        g_ptr_array_add(args, g_strdup("--map-host-loopback"));
+        g_ptr_array_add(args, g_strdup(passt->map_host_loopback));
+    }
+
+    if (passt->map_guest_addr) {
+        g_ptr_array_add(args, g_strdup("--map-guest-addr"));
+        g_ptr_array_add(args, g_strdup(passt->map_guest_addr));
+    }
+
+    if (passt->dns_forward) {
+        g_ptr_array_add(args, g_strdup("--dns-forward"));
+        g_ptr_array_add(args, g_strdup(passt->dns_forward));
+    }
+
+    if (passt->dns_host) {
+        g_ptr_array_add(args, g_strdup("--dns-host"));
+        g_ptr_array_add(args, g_strdup(passt->dns_host));
+    }
+
+    if (passt->has_tcp && !passt->tcp) {
+        g_ptr_array_add(args, g_strdup("--no-tcp"));
+    }
+
+    if (passt->has_udp && !passt->udp) {
+        g_ptr_array_add(args, g_strdup("--no-udp"));
+    }
+
+    if (passt->has_icmp && !passt->icmp) {
+        g_ptr_array_add(args, g_strdup("--no-icmp"));
+    }
+
+    if (passt->has_dhcp && !passt->dhcp) {
+        g_ptr_array_add(args, g_strdup("--no-dhcp"));
+    }
+
+    if (passt->has_ndp && !passt->ndp) {
+        g_ptr_array_add(args, g_strdup("--no-ndp"));
+    }
+    if (passt->has_dhcpv6 && !passt->dhcpv6) {
+        g_ptr_array_add(args, g_strdup("--no-dhcpv6"));
+    }
+
+    if (passt->has_ra && !passt->ra) {
+        g_ptr_array_add(args, g_strdup("--no-ra"));
+    }
+
+    if (passt->has_freebind && passt->freebind) {
+        g_ptr_array_add(args, g_strdup("--freebind"));
+    }
+
+    if (passt->has_ipv4 && !passt->ipv4) {
+        g_ptr_array_add(args, g_strdup("--ipv6-only"));
+    }
+
+    if (passt->has_ipv6 && !passt->ipv6) {
+        g_ptr_array_add(args, g_strdup("--ipv4-only"));
+    }
+
+    if (passt->has_search && passt->search) {
+        const StringList *list = passt->search;
+        GString *domains = g_string_new(list->value->str);
+
+        list = list->next;
+        while (list) {
+            g_string_append(domains, " ");
+            g_string_append(domains, list->value->str);
+            list = list->next;
+        }
+
+        g_ptr_array_add(args, g_strdup("--search"));
+        g_ptr_array_add(args, g_string_free(domains, FALSE));
+    }
+
+    if (passt->has_tcp_ports && passt->tcp_ports) {
+        const StringList *list = passt->tcp_ports;
+        GString *tcp_ports = g_string_new(list->value->str);
+
+        list = list->next;
+        while (list) {
+            g_string_append(tcp_ports, ",");
+            g_string_append(tcp_ports, list->value->str);
+            list = list->next;
+        }
+
+        g_ptr_array_add(args, g_strdup("--tcp-ports"));
+        g_ptr_array_add(args, g_string_free(tcp_ports, FALSE));
+    }
+
+    if (passt->has_udp_ports && passt->udp_ports) {
+        const StringList *list = passt->udp_ports;
+        GString *udp_ports = g_string_new(list->value->str);
+
+        list = list->next;
+        while (list) {
+            g_string_append(udp_ports, ",");
+            g_string_append(udp_ports, list->value->str);
+            list = list->next;
+        }
+
+        g_ptr_array_add(args, g_strdup("--udp-ports"));
+        g_ptr_array_add(args, g_string_free(udp_ports, FALSE));
+    }
+
+    if (passt->has_param && passt->param) {
+        const StringList *list = passt->param;
+
+        while (list) {
+            g_ptr_array_add(args, g_strdup(list->value->str));
+            list = list->next;
+        }
+    }
+
+    /* provide a pid file to be able to kil passt on exit */
+    g_ptr_array_add(args, g_strdup("--pid"));
+    g_ptr_array_add(args, g_strdup(pidfile));
+
+    /* g_subprocess_launcher_take_fd() will set the socket on fd 3 */
+    g_ptr_array_add(args, g_strdup("--fd"));
+    g_ptr_array_add(args, g_strdup("3"));
+
+    g_ptr_array_add(args, NULL);
+
+    return args;
+}
+
+int net_init_passt(const Netdev *netdev, const char *name,
+                   NetClientState *peer, Error **errp)
+{
+    g_autoptr(GError) error = NULL;
+    NetClientState *nc;
+    NetPasstState *s;
+    GPtrArray *args;
+    gchar *pidfile;
+    int pidfd;
+
+    assert(netdev->type == NET_CLIENT_DRIVER_PASST);
+
+    pidfd = g_file_open_tmp("passt-XXXXXX.pid", &pidfile, &error);
+    if (pidfd == -1) {
+        error_setg(errp, "Failed to create temporary file: %s", error->message);
+        return -1;
+    }
+    close(pidfd);
+
+    args = net_passt_decode_args(&netdev->u.passt, pidfile, errp);
+    if (args == NULL) {
+        g_free(pidfile);
+        return -1;
+    }
+
+    nc = qemu_new_net_client(&net_passt_info, peer, "passt", name);
+    s = DO_UPCAST(NetPasstState, data.nc, nc);
+
+    s->args = args;
+    s->pidfile = pidfile;
+
+    if (netdev->u.passt.has_vhost_user && netdev->u.passt.vhost_user) {
+        if (net_passt_vhost_user_init(s, errp) == -1) {
+            qemu_del_net_client(nc);
+            return -1;
+        }
+
+        return 0;
+    }
+
+    if (net_passt_stream_start(s, errp) == -1) {
+        qemu_del_net_client(nc);
+        return -1;
+    }
+
+    return 0;
+}