/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2014 Red Hat, Inc.
 */

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

#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <net/if_arp.h>

#include "nm-glib-aux/nm-dedup-multi.h"
#include "nm-std-aux/unaligned.h"

#include "nm-utils.h"
#include "nm-dhcp-utils.h"
#include "nm-dhcp-options.h"
#include "nm-core-utils.h"
#include "NetworkManagerUtils.h"
#include "platform/nm-platform.h"
#include "nm-dhcp-client-logging.h"
#include "systemd/nm-sd.h"
#include "systemd/nm-sd-utils-dhcp.h"

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

#define NM_TYPE_DHCP_SYSTEMD (nm_dhcp_systemd_get_type())
#define NM_DHCP_SYSTEMD(obj) \
    (G_TYPE_CHECK_INSTANCE_CAST((obj), NM_TYPE_DHCP_SYSTEMD, NMDhcpSystemd))
#define NM_DHCP_SYSTEMD_CLASS(klass) \
    (G_TYPE_CHECK_CLASS_CAST((klass), NM_TYPE_DHCP_SYSTEMD, NMDhcpSystemdClass))
#define NM_IS_DHCP_SYSTEMD(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj), NM_TYPE_DHCP_SYSTEMD))
#define NM_IS_DHCP_SYSTEMD_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass), NM_TYPE_DHCP_SYSTEMD))
#define NM_DHCP_SYSTEMD_GET_CLASS(obj) \
    (G_TYPE_INSTANCE_GET_CLASS((obj), NM_TYPE_DHCP_SYSTEMD, NMDhcpSystemdClass))

typedef struct _NMDhcpSystemd      NMDhcpSystemd;
typedef struct _NMDhcpSystemdClass NMDhcpSystemdClass;

static GType nm_dhcp_systemd_get_type(void);

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

typedef struct {
    sd_dhcp_client * client4;
    sd_dhcp6_client *client6;
    char *           lease_file;

    guint request_count;

    bool privacy : 1;
} NMDhcpSystemdPrivate;

struct _NMDhcpSystemd {
    NMDhcpClient         parent;
    NMDhcpSystemdPrivate _priv;
};

struct _NMDhcpSystemdClass {
    NMDhcpClientClass parent;
};

G_DEFINE_TYPE(NMDhcpSystemd, nm_dhcp_systemd, NM_TYPE_DHCP_CLIENT)

#define NM_DHCP_SYSTEMD_GET_PRIVATE(self) _NM_GET_PRIVATE(self, NMDhcpSystemd, NM_IS_DHCP_SYSTEMD)

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

static NMIP4Config *
lease_to_ip4_config(NMDedupMultiIndex *multi_idx,
                    const char *       iface,
                    int                ifindex,
                    sd_dhcp_lease *    lease,
                    guint32            route_table,
                    guint32            route_metric,
                    GHashTable **      out_options,
                    GError **          error)
{
    gs_unref_object NMIP4Config *ip4_config = NULL;
    gs_unref_hashtable GHashTable *options  = NULL;
    const struct in_addr *         addr_list;
    char                           addr_str[NM_UTILS_INET_ADDRSTRLEN];
    const char *                   s;
    nm_auto_free_gstring GString *str      = NULL;
    gs_free sd_dhcp_route **routes         = NULL;
    const char *const *     search_domains = NULL;
    guint16                 mtu;
    int                     i, num;
    const void *            data;
    gsize                   data_len;
    gboolean                metered                   = FALSE;
    gboolean                has_router_from_classless = FALSE;
    gboolean                has_classless_route       = FALSE;
    gboolean                has_static_route          = FALSE;
    const gint32            ts                        = nm_utils_get_monotonic_timestamp_sec();
    gint64                  ts_time                   = time(NULL);
    struct in_addr          a_address;
    struct in_addr          a_netmask;
    struct in_addr          a_next_server;
    struct in_addr          server_id;
    struct in_addr          broadcast;
    const struct in_addr *  a_router;
    guint32                 a_plen;
    guint32                 a_lifetime;
    guint32                 renewal;
    guint32                 rebinding;
    gs_free nm_sd_dhcp_option *private_options = NULL;

    nm_assert(lease != NULL);

    if (sd_dhcp_lease_get_address(lease, &a_address) < 0) {
        nm_utils_error_set_literal(error,
                                   NM_UTILS_ERROR_UNKNOWN,
                                   "could not get address from lease");
        return NULL;
    }

    if (sd_dhcp_lease_get_netmask(lease, &a_netmask) < 0) {
        nm_utils_error_set_literal(error,
                                   NM_UTILS_ERROR_UNKNOWN,
                                   "could not get netmask from lease");
        return NULL;
    }

    if (sd_dhcp_lease_get_lifetime(lease, &a_lifetime) < 0) {
        nm_utils_error_set_literal(error,
                                   NM_UTILS_ERROR_UNKNOWN,
                                   "could not get lifetime from lease");
        return NULL;
    }

    ip4_config = nm_ip4_config_new(multi_idx, ifindex);

    options = out_options ? nm_dhcp_option_create_options_dict() : NULL;

    _nm_utils_inet4_ntop(a_address.s_addr, addr_str);
    nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_NM_IP_ADDRESS, addr_str);

    a_plen = nm_utils_ip4_netmask_to_prefix(a_netmask.s_addr);
    nm_dhcp_option_add_option(options,
                              AF_INET,
                              NM_DHCP_OPTION_DHCP4_SUBNET_MASK,
                              _nm_utils_inet4_ntop(a_netmask.s_addr, addr_str));

    nm_dhcp_option_add_option_u64(options,
                                  AF_INET,
                                  NM_DHCP_OPTION_DHCP4_IP_ADDRESS_LEASE_TIME,
                                  a_lifetime);
    nm_dhcp_option_add_option_u64(options,
                                  AF_INET,
                                  NM_DHCP_OPTION_DHCP4_NM_EXPIRY,
                                  (guint64)(ts_time + a_lifetime));

    if (sd_dhcp_lease_get_next_server(lease, &a_next_server) == 0) {
        _nm_utils_inet4_ntop(a_next_server.s_addr, addr_str);
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_NM_NEXT_SERVER, addr_str);
    }

    nm_ip4_config_add_address(ip4_config,
                              &((const NMPlatformIP4Address){
                                  .address      = a_address.s_addr,
                                  .peer_address = a_address.s_addr,
                                  .plen         = a_plen,
                                  .addr_source  = NM_IP_CONFIG_SOURCE_DHCP,
                                  .timestamp    = ts,
                                  .lifetime     = a_lifetime,
                                  .preferred    = a_lifetime,
                              }));

    if (sd_dhcp_lease_get_server_identifier(lease, &server_id) >= 0) {
        _nm_utils_inet4_ntop(server_id.s_addr, addr_str);
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_SERVER_ID, addr_str);
    }

    if (sd_dhcp_lease_get_broadcast(lease, &broadcast) >= 0) {
        _nm_utils_inet4_ntop(broadcast.s_addr, addr_str);
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_BROADCAST, addr_str);
    }

    num = sd_dhcp_lease_get_dns(lease, &addr_list);
    if (num > 0) {
        nm_gstring_prepare(&str);
        for (i = 0; i < num; i++) {
            _nm_utils_inet4_ntop(addr_list[i].s_addr, addr_str);
            g_string_append(nm_gstring_add_space_delimiter(str), addr_str);

            if (addr_list[i].s_addr == 0 || nm_ip4_addr_is_localhost(addr_list[i].s_addr)) {
                /* Skip localhost addresses, like also networkd does.
                 * See https://github.com/systemd/systemd/issues/4524. */
                continue;
            }
            nm_ip4_config_add_nameserver(ip4_config, addr_list[i].s_addr);
        }
        nm_dhcp_option_add_option(options,
                                  AF_INET,
                                  NM_DHCP_OPTION_DHCP4_DOMAIN_NAME_SERVER,
                                  str->str);
    }

    num = sd_dhcp_lease_get_search_domains(lease, (char ***) &search_domains);
    if (num > 0) {
        nm_gstring_prepare(&str);
        for (i = 0; i < num; i++) {
            g_string_append(nm_gstring_add_space_delimiter(str), search_domains[i]);
            nm_ip4_config_add_search(ip4_config, search_domains[i]);
        }
        nm_dhcp_option_add_option(options,
                                  AF_INET,
                                  NM_DHCP_OPTION_DHCP4_DOMAIN_SEARCH_LIST,
                                  str->str);
    }

    if (sd_dhcp_lease_get_domainname(lease, &s) >= 0) {
        gs_strfreev char **domains = NULL;
        char **            d;

        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_DOMAIN_NAME, s);

        /* Multiple domains sometimes stuffed into option 15 "Domain Name".
         * As systemd escapes such characters, split them at \\032. */
        domains = g_strsplit(s, "\\032", 0);
        for (d = domains; *d; d++)
            nm_ip4_config_add_domain(ip4_config, *d);
    }

    if (sd_dhcp_lease_get_hostname(lease, &s) >= 0) {
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_HOST_NAME, s);
    }

    num = sd_dhcp_lease_get_routes(lease, &routes);
    if (num > 0) {
        nm_auto_free_gstring GString *str_classless        = NULL;
        nm_auto_free_gstring GString *str_static           = NULL;
        guint32                       default_route_metric = route_metric;

        for (i = 0; i < num; i++) {
            switch (sd_dhcp_route_get_option(routes[i])) {
            case NM_DHCP_OPTION_DHCP4_CLASSLESS_STATIC_ROUTE:
                has_classless_route = TRUE;
                break;
            case NM_DHCP_OPTION_DHCP4_STATIC_ROUTE:
                has_static_route = TRUE;
                break;
            }
        }

        if (has_classless_route)
            str_classless = g_string_sized_new(30);
        if (has_static_route)
            str_static = g_string_sized_new(30);

        for (i = 0; i < num; i++) {
            char           network_net_str[NM_UTILS_INET_ADDRSTRLEN];
            char           gateway_str[NM_UTILS_INET_ADDRSTRLEN];
            guint8         r_plen;
            struct in_addr r_network;
            struct in_addr r_gateway;
            in_addr_t      network_net;
            int            option;
            guint32        m;

            option = sd_dhcp_route_get_option(routes[i]);
            if (!NM_IN_SET(option,
                           NM_DHCP_OPTION_DHCP4_CLASSLESS_STATIC_ROUTE,
                           NM_DHCP_OPTION_DHCP4_STATIC_ROUTE))
                continue;

            if (sd_dhcp_route_get_destination(routes[i], &r_network) < 0)
                continue;
            if (sd_dhcp_route_get_destination_prefix_length(routes[i], &r_plen) < 0 || r_plen > 32)
                continue;
            if (sd_dhcp_route_get_gateway(routes[i], &r_gateway) < 0)
                continue;

            network_net = nm_utils_ip4_address_clear_host_address(r_network.s_addr, r_plen);
            _nm_utils_inet4_ntop(network_net, network_net_str);
            _nm_utils_inet4_ntop(r_gateway.s_addr, gateway_str);

            g_string_append_printf(
                nm_gstring_add_space_delimiter(option == NM_DHCP_OPTION_DHCP4_CLASSLESS_STATIC_ROUTE
                                                   ? str_classless
                                                   : str_static),
                "%s/%d %s",
                network_net_str,
                (int) r_plen,
                gateway_str);

            if (option == NM_DHCP_OPTION_DHCP4_STATIC_ROUTE && has_classless_route) {
                /* RFC 3443: if the DHCP server returns both a Classless Static Routes
                 * option and a Static Routes option, the DHCP client MUST ignore the
                 * Static Routes option. */
                continue;
            }

            if (r_plen == 0 && option == NM_DHCP_OPTION_DHCP4_STATIC_ROUTE) {
                /* for option 33 (static route), RFC 2132 says:
                 *
                 * The default route (0.0.0.0) is an illegal destination for a static
                 * route. */
                continue;
            }

            if (r_plen == 0) {
                /* if there are multiple default routes, we add them with differing
                 * metrics. */
                m = default_route_metric;
                if (default_route_metric < G_MAXUINT32)
                    default_route_metric++;

                has_router_from_classless = TRUE;
            } else
                m = route_metric;

            nm_ip4_config_add_route(
                ip4_config,
                &((const NMPlatformIP4Route){
                    .network       = network_net,
                    .plen          = r_plen,
                    .gateway       = r_gateway.s_addr,
                    .rt_source     = NM_IP_CONFIG_SOURCE_DHCP,
                    .metric        = m,
                    .table_coerced = nm_platform_route_table_coerce(route_table),
                }),
                NULL);
        }

        if (str_classless && str_classless->len > 0)
            nm_dhcp_option_add_option(options,
                                      AF_INET,
                                      NM_DHCP_OPTION_DHCP4_CLASSLESS_STATIC_ROUTE,
                                      str_classless->str);
        if (str_static && str_static->len > 0)
            nm_dhcp_option_add_option(options,
                                      AF_INET,
                                      NM_DHCP_OPTION_DHCP4_STATIC_ROUTE,
                                      str_static->str);
    }

    num = sd_dhcp_lease_get_router(lease, &a_router);
    if (num > 0) {
        guint32 default_route_metric = route_metric;

        nm_gstring_prepare(&str);
        for (i = 0; i < num; i++) {
            guint32 m;

            s = _nm_utils_inet4_ntop(a_router[i].s_addr, addr_str);
            g_string_append(nm_gstring_add_space_delimiter(str), s);

            if (a_router[i].s_addr == 0) {
                /* silently skip 0.0.0.0 */
                continue;
            }

            if (has_router_from_classless) {
                /* If the DHCP server returns both a Classless Static Routes option and a
                 * Router option, the DHCP client MUST ignore the Router option [RFC 3442].
                 *
                 * Be more lenient and ignore the Router option only if Classless Static
                 * Routes contain a default gateway (as other DHCP backends do).
                 */
                continue;
            }

            /* if there are multiple default routes, we add them with differing
             * metrics. */
            m = default_route_metric;
            if (default_route_metric < G_MAXUINT32)
                default_route_metric++;

            nm_ip4_config_add_route(
                ip4_config,
                &((const NMPlatformIP4Route){
                    .rt_source     = NM_IP_CONFIG_SOURCE_DHCP,
                    .gateway       = a_router[i].s_addr,
                    .table_coerced = nm_platform_route_table_coerce(route_table),
                    .metric        = m,
                }),
                NULL);
        }
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_ROUTER, str->str);
    }

    if (sd_dhcp_lease_get_mtu(lease, &mtu) >= 0 && mtu) {
        nm_dhcp_option_add_option_u64(options, AF_INET, NM_DHCP_OPTION_DHCP4_INTERFACE_MTU, mtu);
        nm_ip4_config_set_mtu(ip4_config, mtu, NM_IP_CONFIG_SOURCE_DHCP);
    }

    num = sd_dhcp_lease_get_ntp(lease, &addr_list);
    if (num > 0) {
        nm_gstring_prepare(&str);
        for (i = 0; i < num; i++) {
            _nm_utils_inet4_ntop(addr_list[i].s_addr, addr_str);
            g_string_append(nm_gstring_add_space_delimiter(str), addr_str);
        }
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_NTP_SERVER, str->str);
    }

    if (sd_dhcp_lease_get_root_path(lease, &s) >= 0) {
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_ROOT_PATH, s);
    }

    if (sd_dhcp_lease_get_t1(lease, &renewal) >= 0) {
        nm_dhcp_option_add_option_u64(options,
                                      AF_INET,
                                      NM_DHCP_OPTION_DHCP4_RENEWAL_T1_TIME,
                                      renewal);
    }

    if (sd_dhcp_lease_get_t2(lease, &rebinding) >= 0) {
        nm_dhcp_option_add_option_u64(options,
                                      AF_INET,
                                      NM_DHCP_OPTION_DHCP4_REBINDING_T2_TIME,
                                      rebinding);
    }

    if (sd_dhcp_lease_get_timezone(lease, &s) >= 0) {
        nm_dhcp_option_add_option(options, AF_INET, NM_DHCP_OPTION_DHCP4_NEW_TZDB_TIMEZONE, s);
    }

    if (sd_dhcp_lease_get_vendor_specific(lease, &data, &data_len) >= 0)
        metered = !!memmem(data, data_len, "ANDROID_METERED", NM_STRLEN("ANDROID_METERED"));
    nm_ip4_config_set_metered(ip4_config, metered);

    num = nm_sd_dhcp_lease_get_private_options(lease, &private_options);
    if (num > 0) {
        for (i = 0; i < num; i++) {
            char *option_string;

            option_string = nm_utils_bin2hexstr_full(private_options[i].data,
                                                     private_options[i].data_len,
                                                     ':',
                                                     FALSE,
                                                     NULL);
            if (!options) {
                g_free(option_string);
                continue;
            }
            nm_dhcp_option_take_option(options, AF_INET, private_options[i].code, option_string);
        }
    }
    NM_SET_OUT(out_options, g_steal_pointer(&options));
    return g_steal_pointer(&ip4_config);
}

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

static void
bound4_handle(NMDhcpSystemd *self, gboolean extended)
{
    NMDhcpSystemdPrivate *priv              = NM_DHCP_SYSTEMD_GET_PRIVATE(self);
    const char *          iface             = nm_dhcp_client_get_iface(NM_DHCP_CLIENT(self));
    gs_unref_object NMIP4Config *ip4_config = NULL;
    gs_unref_hashtable GHashTable *options  = NULL;
    sd_dhcp_lease *                lease    = NULL;
    GError *                       error    = NULL;

    if (sd_dhcp_client_get_lease(priv->client4, &lease) < 0 || !lease) {
        _LOGW("no lease!");
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(self), NM_DHCP_STATE_FAIL, NULL, NULL);
        return;
    }

    _LOGD("lease available");

    ip4_config = lease_to_ip4_config(nm_dhcp_client_get_multi_idx(NM_DHCP_CLIENT(self)),
                                     iface,
                                     nm_dhcp_client_get_ifindex(NM_DHCP_CLIENT(self)),
                                     lease,
                                     nm_dhcp_client_get_route_table(NM_DHCP_CLIENT(self)),
                                     nm_dhcp_client_get_route_metric(NM_DHCP_CLIENT(self)),
                                     &options,
                                     &error);
    if (!ip4_config) {
        _LOGW("%s", error->message);
        g_clear_error(&error);
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(self), NM_DHCP_STATE_FAIL, NULL, NULL);
        return;
    }

    nm_dhcp_option_add_requests_to_options(options, AF_INET);
    dhcp_lease_save(lease, priv->lease_file);

    nm_dhcp_client_set_state(NM_DHCP_CLIENT(self),
                             extended ? NM_DHCP_STATE_EXTENDED : NM_DHCP_STATE_BOUND,
                             NM_IP_CONFIG_CAST(ip4_config),
                             options);
}

static int
dhcp_event_cb(sd_dhcp_client *client, int event, gpointer user_data)
{
    NMDhcpSystemd *       self = NM_DHCP_SYSTEMD(user_data);
    NMDhcpSystemdPrivate *priv = NM_DHCP_SYSTEMD_GET_PRIVATE(self);
    char                  addr_str[INET_ADDRSTRLEN];
    sd_dhcp_lease *       lease = NULL;
    struct in_addr        addr;
    int                   r;

    nm_assert(priv->client4 == client);

    _LOGD("client event %d", event);

    switch (event) {
    case SD_DHCP_CLIENT_EVENT_EXPIRED:
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(user_data), NM_DHCP_STATE_EXPIRE, NULL, NULL);
        break;
    case SD_DHCP_CLIENT_EVENT_STOP:
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(user_data), NM_DHCP_STATE_FAIL, NULL, NULL);
        break;
    case SD_DHCP_CLIENT_EVENT_RENEW:
    case SD_DHCP_CLIENT_EVENT_IP_CHANGE:
        bound4_handle(self, TRUE);
        break;
    case SD_DHCP_CLIENT_EVENT_IP_ACQUIRE:
        bound4_handle(self, FALSE);
        break;
    case SD_DHCP_CLIENT_EVENT_SELECTING:
        r = sd_dhcp_client_get_lease(priv->client4, &lease);
        if (r < 0)
            return r;
        r = sd_dhcp_lease_get_server_identifier(lease, &addr);
        if (r < 0)
            return r;
        if (nm_dhcp_client_server_id_is_rejected(NM_DHCP_CLIENT(user_data), &addr)) {
            _LOGD("server-id %s is in the reject-list, ignoring",
                  nm_utils_inet_ntop(AF_INET, &addr, addr_str));
            return -ENOMSG;
        }
        break;
    case SD_DHCP_CLIENT_EVENT_TRANSIENT_FAILURE:
        break;
    default:
        _LOGW("unhandled DHCP event %d", event);
        break;
    }

    return 0;
}

static gboolean
ip4_start(NMDhcpClient *client,
          const char *  dhcp_anycast_addr,
          const char *  last_ip4_address,
          GError **     error)
{
    nm_auto(sd_dhcp_client_unrefp) sd_dhcp_client *sd_client  = NULL;
    NMDhcpSystemd *                                self       = NM_DHCP_SYSTEMD(client);
    NMDhcpSystemdPrivate *                         priv       = NM_DHCP_SYSTEMD_GET_PRIVATE(self);
    gs_free char *                                 lease_file = NULL;
    GBytes *                                       hwaddr;
    const uint8_t *                                hwaddr_arr;
    gsize                                          hwaddr_len;
    int                                            arp_type;
    GBytes *                                       client_id;
    gs_unref_bytes GBytes *client_id_new = NULL;
    GBytes *               vendor_class_identifier;
    const uint8_t *        client_id_arr;
    size_t                 client_id_len;
    struct in_addr         last_addr = {0};
    const char *           hostname;
    const char *           mud_url;
    int                    r, i;
    GBytes *               bcast_hwaddr;
    const uint8_t *        bcast_hwaddr_arr;
    gsize                  bcast_hwaddr_len;

    g_return_val_if_fail(!priv->client4, FALSE);
    g_return_val_if_fail(!priv->client6, FALSE);

    r = sd_dhcp_client_new(&sd_client, FALSE);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to create dhcp-client: %s");
        return FALSE;
    }

    _LOGT("dhcp-client4: set %p", sd_client);

    r = sd_dhcp_client_attach_event(sd_client, NULL, 0);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to attach event: %s");
        return FALSE;
    }

    hwaddr = nm_dhcp_client_get_hw_addr(client);
    if (!hwaddr || !(hwaddr_arr = g_bytes_get_data(hwaddr, &hwaddr_len))
        || (arp_type = nm_utils_arp_type_detect_from_hwaddrlen(hwaddr_len)) < 0) {
        nm_utils_error_set_literal(error, NM_UTILS_ERROR_UNKNOWN, "invalid MAC address");
        return FALSE;
    }

    bcast_hwaddr_arr = NULL;
    if ((bcast_hwaddr = nm_dhcp_client_get_broadcast_hw_addr(NM_DHCP_CLIENT(self)))) {
        bcast_hwaddr_arr = g_bytes_get_data(bcast_hwaddr, &bcast_hwaddr_len);
        if (bcast_hwaddr_len != hwaddr_len)
            bcast_hwaddr_arr = NULL;
    }

    r = sd_dhcp_client_set_mac(sd_client,
                               hwaddr_arr,
                               bcast_hwaddr_arr,
                               hwaddr_len,
                               (guint16) arp_type);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set MAC address: %s");
        return FALSE;
    }

    r = sd_dhcp_client_set_ifindex(sd_client, nm_dhcp_client_get_ifindex(client));
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set ifindex: %s");
        return FALSE;
    }

    nm_dhcp_utils_get_leasefile_path(AF_INET,
                                     "internal",
                                     nm_dhcp_client_get_iface(client),
                                     nm_dhcp_client_get_uuid(client),
                                     &lease_file);

    if (last_ip4_address)
        inet_pton(AF_INET, last_ip4_address, &last_addr);
    else {
        nm_auto(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL;

        dhcp_lease_load(&lease, lease_file);
        if (lease)
            sd_dhcp_lease_get_address(lease, &last_addr);
    }

    if (last_addr.s_addr) {
        r = sd_dhcp_client_set_request_address(sd_client, &last_addr);
        if (r < 0) {
            nm_utils_error_set_errno(error, r, "failed to set last IPv4 address: %s");
            return FALSE;
        }
    }

    client_id = nm_dhcp_client_get_client_id(client);
    if (!client_id) {
        client_id_new = nm_utils_dhcp_client_id_mac(arp_type, hwaddr_arr, hwaddr_len);
        client_id     = client_id_new;
    }

    if (!(client_id_arr = g_bytes_get_data(client_id, &client_id_len)) || client_id_len < 2) {
        /* invalid client-ids are not expected. */
        nm_assert_not_reached();

        nm_utils_error_set_literal(error, NM_UTILS_ERROR_UNKNOWN, "no valid IPv4 client-id");
        return FALSE;
    }

    /* Note that we always set a client-id. In particular for infiniband that is necessary,
     * see https://tools.ietf.org/html/rfc4390#section-2.1 . */
    r = sd_dhcp_client_set_client_id(sd_client,
                                     client_id_arr[0],
                                     client_id_arr + 1,
                                     NM_MIN(client_id_len - 1, _NM_SD_MAX_CLIENT_ID_LEN));
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set IPv4 client-id: %s");
        return FALSE;
    }

    /* Add requested options */
    for (i = 0; i < (int) G_N_ELEMENTS(_nm_dhcp_option_dhcp4_options); i++) {
        if (_nm_dhcp_option_dhcp4_options[i].include) {
            nm_assert(_nm_dhcp_option_dhcp4_options[i].option_num <= 255);
            r = sd_dhcp_client_set_request_option(sd_client,
                                                  _nm_dhcp_option_dhcp4_options[i].option_num);
            nm_assert(r >= 0 || r == -EEXIST);
        }
    }

    hostname = nm_dhcp_client_get_hostname(client);
    if (hostname) {
        /* FIXME: sd-dhcp decides which hostname/FQDN option to send (12 or 81)
         * only based on whether the hostname has a domain part or not. At the
         * moment there is no way to force one or another.
         */
        r = sd_dhcp_client_set_hostname(sd_client, hostname);
        if (r < 0) {
            nm_utils_error_set_errno(error, r, "failed to set DHCP hostname: %s");
            return FALSE;
        }
    }

    mud_url = nm_dhcp_client_get_mud_url(client);
    if (mud_url) {
        r = sd_dhcp_client_set_mud_url(sd_client, mud_url);
        if (r < 0) {
            nm_utils_error_set_errno(error, r, "failed to set DHCP MUDURL: %s");
            return FALSE;
        }
    }

    vendor_class_identifier = nm_dhcp_client_get_vendor_class_identifier(client);
    if (vendor_class_identifier) {
        const char *option_data;
        gsize       len;

        option_data = g_bytes_get_data(vendor_class_identifier, &len);
        nm_assert(option_data);
        nm_assert(len <= 255);

        option_data = nm_strndup_a(300, option_data, len, NULL);

        r = sd_dhcp_client_set_vendor_class_identifier(sd_client, option_data);
        if (r < 0) {
            nm_utils_error_set_errno(error, r, "failed to set DHCP vendor class identifier: %s");
            return FALSE;
        }
    }

    r = sd_dhcp_client_set_callback(sd_client, dhcp_event_cb, client);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set callback: %s");
        return FALSE;
    }

    priv->client4 = g_steal_pointer(&sd_client);

    g_free(priv->lease_file);
    priv->lease_file = g_steal_pointer(&lease_file);

    nm_dhcp_client_set_client_id(client, client_id);

    r = sd_dhcp_client_start(priv->client4);
    if (r < 0) {
        sd_dhcp_client_set_callback(priv->client4, NULL, NULL);
        nm_clear_pointer(&priv->client4, sd_dhcp_client_unref);
        nm_utils_error_set_errno(error, r, "failed to start DHCP client: %s");
        return FALSE;
    }

    nm_dhcp_client_start_timeout(client);
    return TRUE;
}

static NMIP6Config *
lease_to_ip6_config(NMDedupMultiIndex *multi_idx,
                    const char *       iface,
                    int                ifindex,
                    sd_dhcp6_lease *   lease,
                    gboolean           info_only,
                    GHashTable **      out_options,
                    gint32             ts,
                    GError **          error)
{
    gs_unref_object NMIP6Config *ip6_config = NULL;
    gs_unref_hashtable GHashTable *options  = NULL;
    struct in6_addr                tmp_addr;
    const struct in6_addr *        dns;
    uint32_t                       lft_pref, lft_valid;
    char                           addr_str[NM_UTILS_INET_ADDRSTRLEN];
    char **                        domains;
    const char *                   s;
    nm_auto_free_gstring GString *str = NULL;
    int                           num, i;

    nm_assert(lease);

    ip6_config = nm_ip6_config_new(multi_idx, ifindex);

    options = out_options ? nm_dhcp_option_create_options_dict() : NULL;

    sd_dhcp6_lease_reset_address_iter(lease);
    nm_gstring_prepare(&str);
    while (sd_dhcp6_lease_get_address(lease, &tmp_addr, &lft_pref, &lft_valid) >= 0) {
        const NMPlatformIP6Address address = {
            .plen        = 128,
            .address     = tmp_addr,
            .timestamp   = ts,
            .lifetime    = lft_valid,
            .preferred   = lft_pref,
            .addr_source = NM_IP_CONFIG_SOURCE_DHCP,
        };

        nm_ip6_config_add_address(ip6_config, &address);

        _nm_utils_inet6_ntop(&tmp_addr, addr_str);
        g_string_append(nm_gstring_add_space_delimiter(str), addr_str);
    };
    if (str->len)
        nm_dhcp_option_add_option(options, AF_INET6, NM_DHCP_OPTION_DHCP6_NM_IP_ADDRESS, str->str);

    if (!info_only && nm_ip6_config_get_num_addresses(ip6_config) == 0) {
        g_set_error_literal(error,
                            NM_MANAGER_ERROR,
                            NM_MANAGER_ERROR_FAILED,
                            "no address received in managed mode");
        return NULL;
    }

    num = sd_dhcp6_lease_get_dns(lease, &dns);
    if (num > 0) {
        nm_gstring_prepare(&str);
        for (i = 0; i < num; i++) {
            _nm_utils_inet6_ntop(&dns[i], addr_str);
            g_string_append(nm_gstring_add_space_delimiter(str), addr_str);
            nm_ip6_config_add_nameserver(ip6_config, &dns[i]);
        }
        nm_dhcp_option_add_option(options, AF_INET6, NM_DHCP_OPTION_DHCP6_DNS_SERVERS, str->str);
    }

    num = sd_dhcp6_lease_get_domains(lease, &domains);
    if (num > 0) {
        nm_gstring_prepare(&str);
        for (i = 0; i < num; i++) {
            g_string_append(nm_gstring_add_space_delimiter(str), domains[i]);
            nm_ip6_config_add_search(ip6_config, domains[i]);
        }
        nm_dhcp_option_add_option(options, AF_INET6, NM_DHCP_OPTION_DHCP6_DOMAIN_LIST, str->str);
    }

    if (sd_dhcp6_lease_get_fqdn(lease, &s) >= 0) {
        nm_dhcp_option_add_option(options, AF_INET6, NM_DHCP_OPTION_DHCP6_FQDN, s);
    }

    NM_SET_OUT(out_options, g_steal_pointer(&options));
    return g_steal_pointer(&ip6_config);
}

static void
bound6_handle(NMDhcpSystemd *self)
{
    NMDhcpSystemdPrivate *priv              = NM_DHCP_SYSTEMD_GET_PRIVATE(self);
    const gint32          ts                = nm_utils_get_monotonic_timestamp_sec();
    const char *          iface             = nm_dhcp_client_get_iface(NM_DHCP_CLIENT(self));
    gs_unref_object NMIP6Config *ip6_config = NULL;
    gs_unref_hashtable GHashTable *options  = NULL;
    gs_free_error GError *error             = NULL;
    NMPlatformIP6Address  prefix            = {0};
    sd_dhcp6_lease *      lease             = NULL;

    if (sd_dhcp6_client_get_lease(priv->client6, &lease) < 0 || !lease) {
        _LOGW(" no lease!");
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(self), NM_DHCP_STATE_FAIL, NULL, NULL);
        return;
    }

    _LOGD("lease available");

    ip6_config = lease_to_ip6_config(nm_dhcp_client_get_multi_idx(NM_DHCP_CLIENT(self)),
                                     iface,
                                     nm_dhcp_client_get_ifindex(NM_DHCP_CLIENT(self)),
                                     lease,
                                     nm_dhcp_client_get_info_only(NM_DHCP_CLIENT(self)),
                                     &options,
                                     ts,
                                     &error);

    if (!ip6_config) {
        _LOGW("%s", error->message);
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(self), NM_DHCP_STATE_FAIL, NULL, NULL);
        return;
    }

    nm_dhcp_client_set_state(NM_DHCP_CLIENT(self),
                             NM_DHCP_STATE_BOUND,
                             NM_IP_CONFIG_CAST(ip6_config),
                             options);

    sd_dhcp6_lease_reset_pd_prefix_iter(lease);
    while (!sd_dhcp6_lease_get_pd(lease,
                                  &prefix.address,
                                  &prefix.plen,
                                  &prefix.preferred,
                                  &prefix.lifetime)) {
        prefix.timestamp = ts;
        nm_dhcp_client_emit_ipv6_prefix_delegated(NM_DHCP_CLIENT(self), &prefix);
    }
}

static void
dhcp6_event_cb(sd_dhcp6_client *client, int event, gpointer user_data)
{
    NMDhcpSystemd *       self = NM_DHCP_SYSTEMD(user_data);
    NMDhcpSystemdPrivate *priv = NM_DHCP_SYSTEMD_GET_PRIVATE(self);

    nm_assert(priv->client6 == client);

    _LOGD("client event %d", event);

    switch (event) {
    case SD_DHCP6_CLIENT_EVENT_RETRANS_MAX:
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(user_data), NM_DHCP_STATE_TIMEOUT, NULL, NULL);
        break;
    case SD_DHCP6_CLIENT_EVENT_RESEND_EXPIRE:
    case SD_DHCP6_CLIENT_EVENT_STOP:
        nm_dhcp_client_set_state(NM_DHCP_CLIENT(user_data), NM_DHCP_STATE_FAIL, NULL, NULL);
        break;
    case SD_DHCP6_CLIENT_EVENT_IP_ACQUIRE:
    case SD_DHCP6_CLIENT_EVENT_INFORMATION_REQUEST:
        bound6_handle(self);
        break;
    default:
        _LOGW("unhandled event %d", event);
        break;
    }
}

static gboolean
ip6_start(NMDhcpClient *            client,
          const char *              dhcp_anycast_addr,
          const struct in6_addr *   ll_addr,
          NMSettingIP6ConfigPrivacy privacy,
          guint                     needed_prefixes,
          GError **                 error)
{
    NMDhcpSystemd *                                  self      = NM_DHCP_SYSTEMD(client);
    NMDhcpSystemdPrivate *                           priv      = NM_DHCP_SYSTEMD_GET_PRIVATE(self);
    nm_auto(sd_dhcp6_client_unrefp) sd_dhcp6_client *sd_client = NULL;
    const char *                                     hostname;
    const char *                                     mud_url;
    int                                              r, i;
    const guint8 *                                   duid_arr;
    gsize                                            duid_len;
    GBytes *                                         duid;

    g_return_val_if_fail(!priv->client4, FALSE);
    g_return_val_if_fail(!priv->client6, FALSE);

    if (!(duid = nm_dhcp_client_get_client_id(client))
        || !(duid_arr = g_bytes_get_data(duid, &duid_len)) || duid_len < 2) {
        nm_utils_error_set_literal(error, NM_UTILS_ERROR_UNKNOWN, "missing DUID");
        g_return_val_if_reached(FALSE);
    }

    r = sd_dhcp6_client_new(&sd_client);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to create dhcp-client: %s");
        return FALSE;
    }

    _LOGT("dhcp-client6: set %p", sd_client);

    if (nm_dhcp_client_get_info_only(client)) {
        sd_dhcp6_client_set_address_request(sd_client, 0);
        if (needed_prefixes == 0)
            sd_dhcp6_client_set_information_request(sd_client, 1);
    }

    r = sd_dhcp6_client_set_iaid(sd_client, nm_dhcp_client_get_iaid(client));
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set IAID: %s");
        return FALSE;
    }

    r = sd_dhcp6_client_set_duid(sd_client,
                                 unaligned_read_be16(&duid_arr[0]),
                                 &duid_arr[2],
                                 duid_len - 2);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set DUID: %s");
        return FALSE;
    }

    r = sd_dhcp6_client_attach_event(sd_client, NULL, 0);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to attach event: %s");
        return FALSE;
    }

    r = sd_dhcp6_client_set_ifindex(sd_client, nm_dhcp_client_get_ifindex(client));
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set ifindex: %s");
        return FALSE;
    }

    /* Add requested options */
    for (i = 0; i < (int) G_N_ELEMENTS(_nm_dhcp_option_dhcp6_options); i++) {
        if (_nm_dhcp_option_dhcp6_options[i].include) {
            r = sd_dhcp6_client_set_request_option(sd_client,
                                                   _nm_dhcp_option_dhcp6_options[i].option_num);
            nm_assert(r >= 0 || r == -EEXIST);
        }
    }

    mud_url = nm_dhcp_client_get_mud_url(client);
    if (mud_url) {
        r = sd_dhcp6_client_set_request_mud_url(sd_client, mud_url);
        if (r < 0) {
            nm_utils_error_set_errno(error, r, "failed to set mud-url: %s");
            return FALSE;
        }
    }

    if (needed_prefixes > 0) {
        if (needed_prefixes > 1)
            _LOGW("dhcp-client6: only one prefix request is supported");
        /* FIXME: systemd-networkd API only allows to request a
         * single prefix */
        r = sd_dhcp6_client_set_prefix_delegation(sd_client, TRUE);
        if (r < 0) {
            nm_utils_error_set_errno(error, r, "failed to enable prefix delegation: %s");
            return FALSE;
        }
    }

    r = sd_dhcp6_client_set_local_address(sd_client, ll_addr);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set local address: %s");
        return FALSE;
    }

    hostname = nm_dhcp_client_get_hostname(client);
    r        = sd_dhcp6_client_set_fqdn(sd_client, hostname);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set DHCP hostname: %s");
        return FALSE;
    }

    r = sd_dhcp6_client_set_callback(sd_client, dhcp6_event_cb, client);
    if (r < 0) {
        nm_utils_error_set_errno(error, r, "failed to set callback: %s");
        return FALSE;
    }

    priv->client6 = g_steal_pointer(&sd_client);

    r = sd_dhcp6_client_start(priv->client6);
    if (r < 0) {
        sd_dhcp6_client_set_callback(priv->client6, NULL, NULL);
        nm_clear_pointer(&priv->client6, sd_dhcp6_client_unref);
        nm_utils_error_set_errno(error, r, "failed to start client: %s");
        return FALSE;
    }

    nm_dhcp_client_start_timeout(client);
    return TRUE;
}

static void
stop(NMDhcpClient *client, gboolean release)
{
    NMDhcpSystemd *       self = NM_DHCP_SYSTEMD(client);
    NMDhcpSystemdPrivate *priv = NM_DHCP_SYSTEMD_GET_PRIVATE(self);
    int                   r    = 0;

    NM_DHCP_CLIENT_CLASS(nm_dhcp_systemd_parent_class)->stop(client, release);

    _LOGT("dhcp-client%d: stop %p",
          priv->client4 ? '4' : '6',
          priv->client4 ? (gpointer) priv->client4 : (gpointer) priv->client6);

    if (priv->client4) {
        sd_dhcp_client_set_callback(priv->client4, NULL, NULL);
        r = sd_dhcp_client_stop(priv->client4);
    } else if (priv->client6) {
        sd_dhcp6_client_set_callback(priv->client6, NULL, NULL);
        r = sd_dhcp6_client_stop(priv->client6);
    }

    if (r)
        _LOGW("failed to stop client (%d)", r);
}

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

static void
nm_dhcp_systemd_init(NMDhcpSystemd *self)
{}

static void
dispose(GObject *object)
{
    NMDhcpSystemdPrivate *priv = NM_DHCP_SYSTEMD_GET_PRIVATE(object);

    nm_clear_g_free(&priv->lease_file);

    if (priv->client4) {
        sd_dhcp_client_stop(priv->client4);
        sd_dhcp_client_unref(priv->client4);
        priv->client4 = NULL;
    }

    if (priv->client6) {
        sd_dhcp6_client_stop(priv->client6);
        sd_dhcp6_client_unref(priv->client6);
        priv->client6 = NULL;
    }

    G_OBJECT_CLASS(nm_dhcp_systemd_parent_class)->dispose(object);
}

static void
nm_dhcp_systemd_class_init(NMDhcpSystemdClass *sdhcp_class)
{
    NMDhcpClientClass *client_class = NM_DHCP_CLIENT_CLASS(sdhcp_class);
    GObjectClass *     object_class = G_OBJECT_CLASS(sdhcp_class);

    object_class->dispose = dispose;

    client_class->ip4_start = ip4_start;
    client_class->ip6_start = ip6_start;
    client_class->stop      = stop;
}

const NMDhcpClientFactory _nm_dhcp_client_factory_systemd = {
    .name         = "systemd",
    .get_type     = nm_dhcp_systemd_get_type,
    .experimental = TRUE,
};

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

static GType
_get_type_per_addr_family(int addr_family)
{
    nm_assert_addr_family(addr_family);

    if (addr_family == AF_INET)
        return nm_dhcp_nettools_get_type();
    return nm_dhcp_systemd_get_type();
}

const NMDhcpClientFactory _nm_dhcp_client_factory_internal = {
    .name                     = "internal",
    .get_type_per_addr_family = _get_type_per_addr_family,
};
