/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2013 - 2015 Red Hat, Inc.
 */

#include "src/core/nm-default-daemon.h"

#include "nm-device-tun.h"

#include <stdlib.h>
#include <sys/types.h>
#include <linux/if_tun.h>

#include "nm-act-request.h"
#include "nm-device-private.h"
#include "nm-ip4-config.h"
#include "libnm-platform/nm-platform.h"
#include "nm-device-factory.h"
#include "nm-setting-tun.h"
#include "libnm-core-intern/nm-core-internal.h"

#define _NMLOG_DEVICE_TYPE NMDeviceTun
#include "nm-device-logging.h"

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

NM_GOBJECT_PROPERTIES_DEFINE(NMDeviceTun,
                             PROP_OWNER,
                             PROP_GROUP,
                             PROP_MODE,
                             PROP_NO_PI,
                             PROP_VNET_HDR,
                             PROP_MULTI_QUEUE, );

typedef struct {
    NMPlatformLnkTun props;
} NMDeviceTunPrivate;

struct _NMDeviceTun {
    NMDevice           parent;
    NMDeviceTunPrivate _priv;
};

struct _NMDeviceTunClass {
    NMDeviceClass parent;
};

G_DEFINE_TYPE(NMDeviceTun, nm_device_tun, NM_TYPE_DEVICE)

#define NM_DEVICE_TUN_GET_PRIVATE(self) \
    _NM_GET_PRIVATE(self, NMDeviceTun, NM_IS_DEVICE_TUN, NMDevice)

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

static void
update_properties_from_struct(NMDeviceTun *self, const NMPlatformLnkTun *props)
{
    NMDeviceTunPrivate *   priv   = NM_DEVICE_TUN_GET_PRIVATE(self);
    const NMPlatformLnkTun props0 = {};

    if (!props) {
        /* allow passing %NULL to reset all properties. */
        props = &props0;
    }

    g_object_freeze_notify(G_OBJECT(self));

#define CHECK_PROPERTY_CHANGED_VALID(field, prop)                   \
    G_STMT_START                                                    \
    {                                                               \
        if (priv->props.field != props->field                       \
            || priv->props.field##_valid != props->field##_valid) { \
            priv->props.field##_valid = props->field##_valid;       \
            priv->props.field         = props->field;               \
            _notify(self, prop);                                    \
        }                                                           \
    }                                                               \
    G_STMT_END

#define CHECK_PROPERTY_CHANGED(field, prop)      \
    G_STMT_START                                 \
    {                                            \
        if (priv->props.field != props->field) { \
            priv->props.field = props->field;    \
            _notify(self, prop);                 \
        }                                        \
    }                                            \
    G_STMT_END

    CHECK_PROPERTY_CHANGED_VALID(owner, PROP_OWNER);
    CHECK_PROPERTY_CHANGED_VALID(group, PROP_GROUP);
    CHECK_PROPERTY_CHANGED(type, PROP_MODE);
    CHECK_PROPERTY_CHANGED(pi, PROP_NO_PI);
    CHECK_PROPERTY_CHANGED(vnet_hdr, PROP_VNET_HDR);
    CHECK_PROPERTY_CHANGED(multi_queue, PROP_MULTI_QUEUE);

    g_object_thaw_notify(G_OBJECT(self));
}

static void
update_properties(NMDeviceTun *self)
{
    NMPlatformLnkTun        props_storage;
    const NMPlatformLnkTun *props = NULL;
    int                     ifindex;

    ifindex = nm_device_get_ifindex(NM_DEVICE(self));
    if (ifindex > 0
        && nm_platform_link_tun_get_properties(nm_device_get_platform(NM_DEVICE(self)),
                                               ifindex,
                                               &props_storage))
        props = &props_storage;

    update_properties_from_struct(self, props);
}

static NMDeviceCapabilities
get_generic_capabilities(NMDevice *dev)
{
    return NM_DEVICE_CAP_IS_SOFTWARE;
}

static void
link_changed(NMDevice *device, const NMPlatformLink *pllink)
{
    NM_DEVICE_CLASS(nm_device_tun_parent_class)->link_changed(device, pllink);
    update_properties(NM_DEVICE_TUN(device));
}

static gboolean
complete_connection(NMDevice *           device,
                    NMConnection *       connection,
                    const char *         specific_object,
                    NMConnection *const *existing_connections,
                    GError **            error)
{
    NMSettingTun *s_tun;

    nm_utils_complete_generic(nm_device_get_platform(device),
                              connection,
                              NM_SETTING_TUN_SETTING_NAME,
                              existing_connections,
                              NULL,
                              _("TUN connection"),
                              NULL,
                              NULL,
                              TRUE);

    s_tun = nm_connection_get_setting_tun(connection);
    if (!s_tun) {
        g_set_error_literal(error,
                            NM_DEVICE_ERROR,
                            NM_DEVICE_ERROR_INVALID_CONNECTION,
                            "A 'tun' setting is required.");
        return FALSE;
    }

    return TRUE;
}

static void
update_connection(NMDevice *device, NMConnection *connection)
{
    NMDeviceTun *       self = NM_DEVICE_TUN(device);
    NMDeviceTunPrivate *priv = NM_DEVICE_TUN_GET_PRIVATE(self);
    NMSettingTun *      s_tun;
    NMSettingTunMode    mode;
    char                s_buf[100];
    const char *        str;

    /* Note: since we read tun properties from sysctl for older kernels,
     *       we don't get proper change notifications. Make sure that all our
     *       tun properties are up to date at this point. We should not do this,
     *       if we would entirely rely on netlink events. */
    update_properties(NM_DEVICE_TUN(device));

    switch (priv->props.type) {
    case IFF_TUN:
        mode = NM_SETTING_TUN_MODE_TUN;
        break;
    case IFF_TAP:
        mode = NM_SETTING_TUN_MODE_TAP;
        break;
    default:
        /* Huh? */
        return;
    }

    s_tun = nm_connection_get_setting_tun(connection);
    if (!s_tun) {
        s_tun = (NMSettingTun *) nm_setting_tun_new();
        nm_connection_add_setting(connection, (NMSetting *) s_tun);
    }

    if (mode != nm_setting_tun_get_mode(s_tun))
        g_object_set(G_OBJECT(s_tun), NM_SETTING_TUN_MODE, (guint) mode, NULL);

    str = priv->props.owner_valid ? nm_sprintf_buf(s_buf, "%" G_GINT32_FORMAT, priv->props.owner)
                                  : NULL;
    if (!nm_streq0(str, nm_setting_tun_get_owner(s_tun)))
        g_object_set(G_OBJECT(s_tun), NM_SETTING_TUN_OWNER, str, NULL);

    str = priv->props.group_valid ? nm_sprintf_buf(s_buf, "%" G_GINT32_FORMAT, priv->props.group)
                                  : NULL;
    if (!nm_streq0(str, nm_setting_tun_get_group(s_tun)))
        g_object_set(G_OBJECT(s_tun), NM_SETTING_TUN_GROUP, str, NULL);

    if (priv->props.pi != nm_setting_tun_get_pi(s_tun))
        g_object_set(G_OBJECT(s_tun), NM_SETTING_TUN_PI, (gboolean) priv->props.pi, NULL);
    if (priv->props.vnet_hdr != nm_setting_tun_get_vnet_hdr(s_tun))
        g_object_set(G_OBJECT(s_tun),
                     NM_SETTING_TUN_VNET_HDR,
                     (gboolean) priv->props.vnet_hdr,
                     NULL);
    if (priv->props.multi_queue != nm_setting_tun_get_multi_queue(s_tun))
        g_object_set(G_OBJECT(s_tun),
                     NM_SETTING_TUN_MULTI_QUEUE,
                     (gboolean) priv->props.multi_queue,
                     NULL);
}

static gboolean
create_and_realize(NMDevice *             device,
                   NMConnection *         connection,
                   NMDevice *             parent,
                   const NMPlatformLink **out_plink,
                   GError **              error)
{
    const char *     iface = nm_device_get_iface(device);
    NMPlatformLnkTun props = {};
    NMSettingTun *   s_tun;
    gint64           owner;
    gint64           group;
    int              r;

    s_tun = nm_connection_get_setting_tun(connection);
    g_return_val_if_fail(s_tun, FALSE);

    switch (nm_setting_tun_get_mode(s_tun)) {
    case NM_SETTING_TUN_MODE_TAP:
        props.type = IFF_TAP;
        break;
    case NM_SETTING_TUN_MODE_TUN:
        props.type = IFF_TUN;
        break;
    default:
        g_return_val_if_reached(FALSE);
    }

    owner = _nm_utils_ascii_str_to_int64(nm_setting_tun_get_owner(s_tun), 10, 0, G_MAXINT32, -1);
    if (owner != -1) {
        props.owner_valid = TRUE;
        props.owner       = owner;
    }
    group = _nm_utils_ascii_str_to_int64(nm_setting_tun_get_group(s_tun), 10, 0, G_MAXINT32, -1);
    if (group != -1) {
        props.group_valid = TRUE;
        props.group       = group;
    }

    props.pi          = nm_setting_tun_get_pi(s_tun);
    props.vnet_hdr    = nm_setting_tun_get_vnet_hdr(s_tun);
    props.multi_queue = nm_setting_tun_get_multi_queue(s_tun);
    props.persist     = TRUE;

    r = nm_platform_link_tun_add(nm_device_get_platform(device), iface, &props, out_plink, NULL);
    if (r < 0) {
        g_set_error(error,
                    NM_DEVICE_ERROR,
                    NM_DEVICE_ERROR_CREATION_FAILED,
                    "Failed to create TUN/TAP interface '%s' for '%s': %s",
                    iface,
                    nm_connection_get_id(connection),
                    nm_strerror(r));
        return FALSE;
    }

    return TRUE;
}

static gboolean
_same_og(const char *str, gboolean og_valid, guint32 og_num)
{
    gint64 v;

    v = _nm_utils_ascii_str_to_int64(str, 10, 0, G_MAXINT32, -1);
    return (!og_valid && (v == (gint64) -1)) || (og_valid && (((guint32) v) == og_num));
}

static gboolean
check_connection_compatible(NMDevice *device, NMConnection *connection, GError **error)
{
    NMDeviceTun *       self = NM_DEVICE_TUN(device);
    NMDeviceTunPrivate *priv = NM_DEVICE_TUN_GET_PRIVATE(self);
    NMSettingTunMode    mode;
    NMSettingTun *      s_tun;

    if (!NM_DEVICE_CLASS(nm_device_tun_parent_class)
             ->check_connection_compatible(device, connection, error))
        return FALSE;

    if (nm_device_is_real(device)) {
        switch (priv->props.type) {
        case IFF_TUN:
            mode = NM_SETTING_TUN_MODE_TUN;
            break;
        case IFF_TAP:
            mode = NM_SETTING_TUN_MODE_TAP;
            break;
        default:
            nm_utils_error_set_literal(error,
                                       NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
                                       "invalid tun type on device");
            return FALSE;
        }

        s_tun = nm_connection_get_setting_tun(connection);

        if (mode != nm_setting_tun_get_mode(s_tun)) {
            nm_utils_error_set_literal(error,
                                       NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
                                       "tun mode setting mismatches");
            return FALSE;
        }
        if (!_same_og(nm_setting_tun_get_owner(s_tun),
                      priv->props.owner_valid,
                      priv->props.owner)) {
            nm_utils_error_set_literal(error,
                                       NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
                                       "tun owner setting mismatches");
            return FALSE;
        }
        if (!_same_og(nm_setting_tun_get_group(s_tun),
                      priv->props.group_valid,
                      priv->props.group)) {
            nm_utils_error_set_literal(error,
                                       NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
                                       "tun group setting mismatches");
            return FALSE;
        }
        if (nm_setting_tun_get_pi(s_tun) != priv->props.pi) {
            nm_utils_error_set_literal(error,
                                       NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
                                       "tun pi setting mismatches");
            return FALSE;
        }
        if (nm_setting_tun_get_vnet_hdr(s_tun) != priv->props.vnet_hdr) {
            nm_utils_error_set_literal(error,
                                       NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
                                       "tun vnet-hdr setting mismatches");
            return FALSE;
        }
        if (nm_setting_tun_get_multi_queue(s_tun) != priv->props.multi_queue) {
            nm_utils_error_set_literal(error,
                                       NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
                                       "tun multi-queue setting mismatches");
            return FALSE;
        }
    }

    return TRUE;
}

static NMActStageReturn
act_stage1_prepare(NMDevice *device, NMDeviceStateReason *out_failure_reason)
{
    NMDeviceTun *       self = NM_DEVICE_TUN(device);
    NMDeviceTunPrivate *priv = NM_DEVICE_TUN_GET_PRIVATE(self);

    if (priv->props.type == IFF_TUN) {
        /* Nothing to do for TUN devices */
    } else {
        if (!nm_device_hw_addr_set_cloned(device,
                                          nm_device_get_applied_connection(device),
                                          FALSE)) {
            *out_failure_reason = NM_DEVICE_STATE_REASON_CONFIG_FAILED;
            return NM_ACT_STAGE_RETURN_FAILURE;
        }
    }

    return NM_ACT_STAGE_RETURN_SUCCESS;
}

static void
unrealize_notify(NMDevice *device)
{
    NM_DEVICE_CLASS(nm_device_tun_parent_class)->unrealize_notify(device);
    update_properties_from_struct(NM_DEVICE_TUN(device), NULL);
}

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

static void
get_property(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
    NMDeviceTun *       self = NM_DEVICE_TUN(object);
    NMDeviceTunPrivate *priv = NM_DEVICE_TUN_GET_PRIVATE(self);
    const char *        s;

    switch (prop_id) {
    case PROP_OWNER:
        g_value_set_int64(value,
                          priv->props.owner_valid ? (gint64) priv->props.owner : (gint64) -1);
        break;
    case PROP_GROUP:
        g_value_set_int64(value,
                          priv->props.group_valid ? (gint64) priv->props.group : (gint64) -1);
        break;
    case PROP_MODE:
        switch (priv->props.type) {
        case IFF_TUN:
            s = "tun";
            break;
        case IFF_TAP:
            s = "tap";
            break;
        default:
            s = NULL;
            break;
        }
        g_value_set_static_string(value, s);
        break;
    case PROP_NO_PI:
        g_value_set_boolean(value, !priv->props.pi);
        break;
    case PROP_VNET_HDR:
        g_value_set_boolean(value, priv->props.vnet_hdr);
        break;
    case PROP_MULTI_QUEUE:
        g_value_set_boolean(value, priv->props.multi_queue);
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
        break;
    }
}

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

static void
nm_device_tun_init(NMDeviceTun *self)
{}

static const NMDBusInterfaceInfoExtended interface_info_device_tun = {
    .parent = NM_DEFINE_GDBUS_INTERFACE_INFO_INIT(
        NM_DBUS_INTERFACE_DEVICE_TUN,
        .properties = NM_DEFINE_GDBUS_PROPERTY_INFOS(
            NM_DEFINE_DBUS_PROPERTY_INFO_EXTENDED_READABLE("Owner", "x", NM_DEVICE_TUN_OWNER),
            NM_DEFINE_DBUS_PROPERTY_INFO_EXTENDED_READABLE("Group", "x", NM_DEVICE_TUN_GROUP),
            NM_DEFINE_DBUS_PROPERTY_INFO_EXTENDED_READABLE("Mode", "s", NM_DEVICE_TUN_MODE),
            NM_DEFINE_DBUS_PROPERTY_INFO_EXTENDED_READABLE("NoPi", "b", NM_DEVICE_TUN_NO_PI),
            NM_DEFINE_DBUS_PROPERTY_INFO_EXTENDED_READABLE("VnetHdr", "b", NM_DEVICE_TUN_VNET_HDR),
            NM_DEFINE_DBUS_PROPERTY_INFO_EXTENDED_READABLE("MultiQueue",
                                                           "b",
                                                           NM_DEVICE_TUN_MULTI_QUEUE),
            NM_DEFINE_DBUS_PROPERTY_INFO_EXTENDED_READABLE("HwAddress",
                                                           "s",
                                                           NM_DEVICE_HW_ADDRESS), ), ),
};

static void
nm_device_tun_class_init(NMDeviceTunClass *klass)
{
    GObjectClass *     object_class      = G_OBJECT_CLASS(klass);
    NMDBusObjectClass *dbus_object_class = NM_DBUS_OBJECT_CLASS(klass);
    NMDeviceClass *    device_class      = NM_DEVICE_CLASS(klass);

    object_class->get_property = get_property;

    dbus_object_class->interface_infos = NM_DBUS_INTERFACE_INFOS(&interface_info_device_tun);

    device_class->connection_type_supported        = NM_SETTING_TUN_SETTING_NAME;
    device_class->connection_type_check_compatible = NM_SETTING_TUN_SETTING_NAME;
    device_class->link_types                       = NM_DEVICE_DEFINE_LINK_TYPES(NM_LINK_TYPE_TUN);

    device_class->link_changed                = link_changed;
    device_class->complete_connection         = complete_connection;
    device_class->check_connection_compatible = check_connection_compatible;
    device_class->create_and_realize          = create_and_realize;
    device_class->get_generic_capabilities    = get_generic_capabilities;
    device_class->unrealize_notify            = unrealize_notify;
    device_class->update_connection           = update_connection;
    device_class->act_stage1_prepare          = act_stage1_prepare;
    device_class->get_configured_mtu          = nm_device_get_configured_mtu_for_wired;

    obj_properties[PROP_OWNER] = g_param_spec_int64(NM_DEVICE_TUN_OWNER,
                                                    "",
                                                    "",
                                                    -1,
                                                    G_MAXUINT32,
                                                    -1,
                                                    G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

    obj_properties[PROP_GROUP] = g_param_spec_int64(NM_DEVICE_TUN_GROUP,
                                                    "",
                                                    "",
                                                    -1,
                                                    G_MAXUINT32,
                                                    -1,
                                                    G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

    obj_properties[PROP_MODE] = g_param_spec_string(NM_DEVICE_TUN_MODE,
                                                    "",
                                                    "",
                                                    NULL,
                                                    G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

    obj_properties[PROP_NO_PI] = g_param_spec_boolean(NM_DEVICE_TUN_NO_PI,
                                                      "",
                                                      "",
                                                      FALSE,
                                                      G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

    obj_properties[PROP_VNET_HDR] = g_param_spec_boolean(NM_DEVICE_TUN_VNET_HDR,
                                                         "",
                                                         "",
                                                         FALSE,
                                                         G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

    obj_properties[PROP_MULTI_QUEUE] =
        g_param_spec_boolean(NM_DEVICE_TUN_MULTI_QUEUE,
                             "",
                             "",
                             FALSE,
                             G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);

    g_object_class_install_properties(object_class, _PROPERTY_ENUMS_LAST, obj_properties);
}

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

#define NM_TYPE_TUN_DEVICE_FACTORY (nm_tun_device_factory_get_type())
#define NM_TUN_DEVICE_FACTORY(obj) \
    (G_TYPE_CHECK_INSTANCE_CAST((obj), NM_TYPE_TUN_DEVICE_FACTORY, NMTunDeviceFactory))

static NMDevice *
create_device(NMDeviceFactory *     factory,
              const char *          iface,
              const NMPlatformLink *plink,
              NMConnection *        connection,
              gboolean *            out_ignore)
{
    g_return_val_if_fail(!plink || plink->type == NM_LINK_TYPE_TUN, NULL);
    g_return_val_if_fail(!connection
                             || nm_streq0(nm_connection_get_connection_type(connection),
                                          NM_SETTING_TUN_SETTING_NAME),
                         NULL);

    return g_object_new(NM_TYPE_DEVICE_TUN,
                        NM_DEVICE_IFACE,
                        iface,
                        NM_DEVICE_TYPE_DESC,
                        "Tun",
                        NM_DEVICE_DEVICE_TYPE,
                        NM_DEVICE_TYPE_TUN,
                        NM_DEVICE_LINK_TYPE,
                        (guint) NM_LINK_TYPE_TUN,
                        NULL);
}

NM_DEVICE_FACTORY_DEFINE_INTERNAL(
    TUN,
    Tun,
    tun,
    NM_DEVICE_FACTORY_DECLARE_LINK_TYPES(NM_LINK_TYPE_TUN)
        NM_DEVICE_FACTORY_DECLARE_SETTING_TYPES(NM_SETTING_TUN_SETTING_NAME),
    factory_class->create_device = create_device;);
