/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <netinet/in.h>
#include <linux/if_arp.h>

#include "bus-error.h"
#include "dhcp-internal.h"
#include "dhcp6-internal.h"
#include "escape.h"
#include "in-addr-util.h"
#include "networkd-dhcp-common.h"
#include "networkd-link.h"
#include "networkd-manager.h"
#include "networkd-network.h"
#include "parse-util.h"
#include "socket-util.h"
#include "string-table.h"
#include "strv.h"

bool link_dhcp_enabled(Link *link, int family) {
        assert(link);
        assert(IN_SET(family, AF_INET, AF_INET6));

        if (family == AF_INET6 && !socket_ipv6_is_supported())
                return false;

        if (link->flags & IFF_LOOPBACK)
                return false;

        if (link->iftype == ARPHRD_CAN)
                return false;

        if (!link->network)
                return false;

        return link->network->dhcp & (family == AF_INET ? ADDRESS_FAMILY_IPV4 : ADDRESS_FAMILY_IPV6);
}

void network_adjust_dhcp(Network *network) {
        assert(network);
        assert(network->dhcp >= 0);

        if (network->dhcp == ADDRESS_FAMILY_NO)
                return;

        /* Bonding slave does not support addressing. */
        if (network->bond) {
                log_warning("%s: Cannot enable DHCP= when Bond= is specified, disabling DHCP=.",
                            network->filename);
                network->dhcp = ADDRESS_FAMILY_NO;
                return;
        }

        if (!FLAGS_SET(network->link_local, ADDRESS_FAMILY_IPV6) &&
            FLAGS_SET(network->dhcp, ADDRESS_FAMILY_IPV6)) {
                log_warning("%s: DHCPv6 client is enabled but IPv6 link local addressing is disabled. "
                            "Disabling DHCPv6 client.", network->filename);
                SET_FLAG(network->dhcp, ADDRESS_FAMILY_IPV6, false);
        }
}

static struct DUID fallback_duid = { .type = DUID_TYPE_EN };
DUID* link_get_duid(Link *link) {
        if (link->network->duid.type != _DUID_TYPE_INVALID)
                return &link->network->duid;
        else if (link->hw_addr.length == 0 && IN_SET(link->manager->duid.type, DUID_TYPE_LLT, DUID_TYPE_LL))
                /* Fallback to DUID that works without MAC address.
                 * This is useful for tunnel devices without MAC address. */
                return &fallback_duid;
        else
                return &link->manager->duid;
}

static int duid_set_uuid(DUID *duid, sd_id128_t uuid) {
        assert(duid);

        if (duid->raw_data_len > 0)
                return 0;

        if (duid->type != DUID_TYPE_UUID)
                return -EINVAL;

        memcpy(&duid->raw_data, &uuid, sizeof(sd_id128_t));
        duid->raw_data_len = sizeof(sd_id128_t);

        return 1;
}

static int get_product_uuid_handler(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
        Manager *manager = userdata;
        const sd_bus_error *e;
        const void *a;
        size_t sz;
        DUID *duid;
        Link *link;
        int r;

        assert(m);
        assert(manager);

        e = sd_bus_message_get_error(m);
        if (e) {
                r = sd_bus_error_get_errno(e);
                log_warning_errno(r, "Could not get product UUID. Falling back to use machine-app-specific ID as DUID-UUID: %s",
                                  bus_error_message(e, r));
                goto configure;
        }

        r = sd_bus_message_read_array(m, 'y', &a, &sz);
        if (r < 0) {
                log_warning_errno(r, "Failed to get product UUID. Falling back to use machine-app-specific ID as DUID-UUID: %m");
                goto configure;
        }

        if (sz != sizeof(sd_id128_t)) {
                log_warning("Invalid product UUID. Falling back to use machine-app-specific ID as DUID-UUID.");
                goto configure;
        }

        memcpy(&manager->product_uuid, a, sz);
        while ((duid = set_steal_first(manager->duids_requesting_uuid)))
                (void) duid_set_uuid(duid, manager->product_uuid);

        manager->duids_requesting_uuid = set_free(manager->duids_requesting_uuid);

configure:
        while ((link = set_steal_first(manager->links_requesting_uuid))) {
                link_unref(link);

                r = link_configure(link);
                if (r < 0)
                        link_enter_failed(link);
        }

        manager->links_requesting_uuid = set_free(manager->links_requesting_uuid);

        /* To avoid calling GetProductUUID() bus method so frequently, set the flag below
         * even if the method fails. */
        manager->has_product_uuid = true;

        return 1;
}

int manager_request_product_uuid(Manager *m, Link *link) {
        int r;

        assert(m);

        if (m->has_product_uuid)
                return 0;

        log_debug("Requesting product UUID");

        if (link) {
                DUID *duid;

                assert_se(duid = link_get_duid(link));

                r = set_ensure_put(&m->links_requesting_uuid, NULL, link);
                if (r < 0)
                        return log_oom();
                if (r > 0)
                        link_ref(link);

                r = set_ensure_put(&m->duids_requesting_uuid, NULL, duid);
                if (r < 0)
                        return log_oom();
        }

        if (!m->bus || sd_bus_is_ready(m->bus) <= 0) {
                log_debug("Not connected to system bus, requesting product UUID later.");
                return 0;
        }

        r = sd_bus_call_method_async(
                        m->bus,
                        NULL,
                        "org.freedesktop.hostname1",
                        "/org/freedesktop/hostname1",
                        "org.freedesktop.hostname1",
                        "GetProductUUID",
                        get_product_uuid_handler,
                        m,
                        "b",
                        false);
        if (r < 0)
                return log_warning_errno(r, "Failed to get product UUID: %m");

        return 0;
}

static bool link_requires_uuid(Link *link) {
        const DUID *duid;

        assert(link);
        assert(link->manager);
        assert(link->network);

        duid = link_get_duid(link);
        if (duid->type != DUID_TYPE_UUID || duid->raw_data_len != 0)
                return false;

        if (link_dhcp4_enabled(link) && IN_SET(link->network->dhcp_client_identifier, DHCP_CLIENT_ID_DUID, DHCP_CLIENT_ID_DUID_ONLY))
                return true;

        if (link_dhcp6_enabled(link) || link_ipv6_accept_ra_enabled(link))
                return true;

        return false;
}

int link_configure_duid(Link *link) {
        Manager *m;
        DUID *duid;
        int r;

        assert(link);
        assert(link->manager);
        assert(link->network);

        m = link->manager;
        duid = link_get_duid(link);

        if (!link_requires_uuid(link))
                return 1;

        if (m->has_product_uuid) {
                (void) duid_set_uuid(duid, m->product_uuid);
                return 1;
        }

        if (!m->links_requesting_uuid) {
                r = manager_request_product_uuid(m, link);
                if (r < 0) {
                        if (r == -ENOMEM)
                                return r;

                        log_link_warning_errno(link, r,
                                               "Failed to get product UUID. Falling back to use machine-app-specific ID as DUID-UUID: %m");
                        return 1;
                }
        } else {
                r = set_put(m->links_requesting_uuid, link);
                if (r < 0)
                        return log_oom();
                if (r > 0)
                        link_ref(link);

                r = set_put(m->duids_requesting_uuid, duid);
                if (r < 0)
                        return log_oom();
        }

        return 0;
}

int config_parse_dhcp(
                const char* unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        AddressFamily *dhcp = data, s;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(data);

        /* Note that this is mostly like
         * config_parse_address_family(), except that it
         * understands some old names for the enum values */

        s = address_family_from_string(rvalue);
        if (s < 0) {

                /* Previously, we had a slightly different enum here,
                 * support its values for compatibility. */

                if (streq(rvalue, "none"))
                        s = ADDRESS_FAMILY_NO;
                else if (streq(rvalue, "v4"))
                        s = ADDRESS_FAMILY_IPV4;
                else if (streq(rvalue, "v6"))
                        s = ADDRESS_FAMILY_IPV6;
                else if (streq(rvalue, "both"))
                        s = ADDRESS_FAMILY_YES;
                else {
                        log_syntax(unit, LOG_WARNING, filename, line, 0,
                                   "Failed to parse DHCP option, ignoring: %s", rvalue);
                        return 0;
                }

                log_syntax(unit, LOG_WARNING, filename, line, 0,
                           "DHCP=%s is deprecated, please use DHCP=%s instead.",
                           rvalue, address_family_to_string(s));
        }

        *dhcp = s;
        return 0;
}

int config_parse_dhcp_route_metric(
                const char* unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        Network *network = data;
        uint32_t metric;
        int r;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(data);

        r = safe_atou32(rvalue, &metric);
        if (r < 0) {
                log_syntax(unit, LOG_WARNING, filename, line, r,
                           "Failed to parse RouteMetric=%s, ignoring assignment: %m", rvalue);
                return 0;
        }

        if (streq_ptr(section, "DHCPv4")) {
                network->dhcp_route_metric = metric;
                network->dhcp_route_metric_set = true;
        } else if (streq_ptr(section, "DHCPv6")) {
                network->dhcp6_route_metric = metric;
                network->dhcp6_route_metric_set = true;
        } else { /* [DHCP] section */
                if (!network->dhcp_route_metric_set)
                        network->dhcp_route_metric = metric;
                if (!network->dhcp6_route_metric_set)
                        network->dhcp6_route_metric = metric;
        }

        return 0;
}

int config_parse_dhcp_use_dns(
                const char* unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        Network *network = data;
        int r;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(data);

        r = parse_boolean(rvalue);
        if (r < 0) {
                log_syntax(unit, LOG_WARNING, filename, line, r,
                           "Failed to parse UseDNS=%s, ignoring assignment: %m", rvalue);
                return 0;
        }

        if (streq_ptr(section, "DHCPv4")) {
                network->dhcp_use_dns = r;
                network->dhcp_use_dns_set = true;
        } else if (streq_ptr(section, "DHCPv6")) {
                network->dhcp6_use_dns = r;
                network->dhcp6_use_dns_set = true;
        } else { /* [DHCP] section */
                if (!network->dhcp_use_dns_set)
                        network->dhcp_use_dns = r;
                if (!network->dhcp6_use_dns_set)
                        network->dhcp6_use_dns = r;
        }

        return 0;
}

int config_parse_dhcp_use_ntp(
                const char* unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        Network *network = data;
        int r;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(data);

        r = parse_boolean(rvalue);
        if (r < 0) {
                log_syntax(unit, LOG_WARNING, filename, line, r,
                           "Failed to parse UseNTP=%s, ignoring assignment: %m", rvalue);
                return 0;
        }

        if (streq_ptr(section, "DHCPv4")) {
                network->dhcp_use_ntp = r;
                network->dhcp_use_ntp_set = true;
        } else if (streq_ptr(section, "DHCPv6")) {
                network->dhcp6_use_ntp = r;
                network->dhcp6_use_ntp_set = true;
        } else { /* [DHCP] section */
                if (!network->dhcp_use_ntp_set)
                        network->dhcp_use_ntp = r;
                if (!network->dhcp6_use_ntp_set)
                        network->dhcp6_use_ntp = r;
        }

        return 0;
}

int config_parse_section_route_table(
                const char *unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        Network *network = data;
        uint32_t rt;
        int r;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(data);

        r = safe_atou32(rvalue, &rt);
        if (r < 0) {
                log_syntax(unit, LOG_WARNING, filename, line, r,
                           "Failed to parse RouteTable=%s, ignoring assignment: %m", rvalue);
                return 0;
        }

        if (STRPTR_IN_SET(section, "DHCP", "DHCPv4")) {
                network->dhcp_route_table = rt;
                network->dhcp_route_table_set = true;
        } else { /* section is IPv6AcceptRA */
                network->ipv6_accept_ra_route_table = rt;
                network->ipv6_accept_ra_route_table_set = true;
        }

        return 0;
}

int config_parse_iaid(const char *unit,
                      const char *filename,
                      unsigned line,
                      const char *section,
                      unsigned section_line,
                      const char *lvalue,
                      int ltype,
                      const char *rvalue,
                      void *data,
                      void *userdata) {
        Network *network = data;
        uint32_t iaid;
        int r;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(network);

        r = safe_atou32(rvalue, &iaid);
        if (r < 0) {
                log_syntax(unit, LOG_WARNING, filename, line, r,
                           "Unable to read IAID, ignoring assignment: %s", rvalue);
                return 0;
        }

        network->iaid = iaid;
        network->iaid_set = true;

        return 0;
}

int config_parse_dhcp_user_class(
                const char *unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        char ***l = data;
        int r;

        assert(l);
        assert(lvalue);
        assert(rvalue);

        if (isempty(rvalue)) {
                *l = strv_free(*l);
                return 0;
        }

        for (const char *p = rvalue;;) {
                _cleanup_free_ char *w = NULL;

                r = extract_first_word(&p, &w, NULL, EXTRACT_CUNESCAPE|EXTRACT_UNQUOTE);
                if (r == -ENOMEM)
                        return log_oom();
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to split user classes option, ignoring: %s", rvalue);
                        return 0;
                }
                if (r == 0)
                        return 0;

                if (ltype == AF_INET) {
                        if (strlen(w) > UINT8_MAX) {
                                log_syntax(unit, LOG_WARNING, filename, line, 0,
                                           "%s length is not in the range 1-255, ignoring.", w);
                                continue;
                        }
                } else {
                        if (strlen(w) > UINT16_MAX) {
                                log_syntax(unit, LOG_WARNING, filename, line, 0,
                                           "%s length is not in the range 1-65535, ignoring.", w);
                                continue;
                        }
                }

                r = strv_push(l, w);
                if (r < 0)
                        return log_oom();

                w = NULL;
        }
}

int config_parse_dhcp_vendor_class(
                const char *unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {
        char ***l = data;
        int r;

        assert(l);
        assert(lvalue);
        assert(rvalue);

        if (isempty(rvalue)) {
                *l = strv_free(*l);
                return 0;
        }

        for (const char *p = rvalue;;) {
                _cleanup_free_ char *w = NULL;

                r = extract_first_word(&p, &w, NULL, EXTRACT_CUNESCAPE|EXTRACT_UNQUOTE);
                if (r == -ENOMEM)
                        return log_oom();
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to split vendor classes option, ignoring: %s", rvalue);
                        return 0;
                }
                if (r == 0)
                        return 0;

                if (strlen(w) > UINT8_MAX) {
                        log_syntax(unit, LOG_WARNING, filename, line, 0,
                                   "%s length is not in the range 1-255, ignoring.", w);
                        continue;
                }

                r = strv_push(l, w);
                if (r < 0)
                        return log_oom();

                w = NULL;
        }
}

int config_parse_dhcp_send_option(
                const char *unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        _cleanup_(sd_dhcp_option_unrefp) sd_dhcp_option *opt4 = NULL, *old4 = NULL;
        _cleanup_(sd_dhcp6_option_unrefp) sd_dhcp6_option *opt6 = NULL, *old6 = NULL;
        uint32_t uint32_data, enterprise_identifier = 0;
        _cleanup_free_ char *word = NULL, *q = NULL;
        OrderedHashmap **options = data;
        uint16_t u16, uint16_data;
        union in_addr_union addr;
        DHCPOptionDataType type;
        uint8_t u8, uint8_data;
        const void *udata;
        const char *p;
        ssize_t sz;
        int r;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(data);

        if (isempty(rvalue)) {
                *options = ordered_hashmap_free(*options);
                return 0;
        }

        p = rvalue;
        if (ltype == AF_INET6 && streq(lvalue, "SendVendorOption")) {
                r = extract_first_word(&p, &word, ":", 0);
                if (r == -ENOMEM)
                        return log_oom();
                if (r <= 0 || isempty(p)) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Invalid DHCP option, ignoring assignment: %s", rvalue);
                        return 0;
                }

                r = safe_atou32(word, &enterprise_identifier);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to parse DHCPv6 enterprise identifier data, ignoring assignment: %s", p);
                        return 0;
                }
                word = mfree(word);
        }

        r = extract_first_word(&p, &word, ":", 0);
        if (r == -ENOMEM)
                return log_oom();
        if (r <= 0 || isempty(p)) {
                log_syntax(unit, LOG_WARNING, filename, line, r,
                           "Invalid DHCP option, ignoring assignment: %s", rvalue);
                return 0;
        }

        if (ltype == AF_INET6) {
                r = safe_atou16(word, &u16);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Invalid DHCP option, ignoring assignment: %s", rvalue);
                         return 0;
                }
                if (u16 < 1 || u16 >= UINT16_MAX) {
                        log_syntax(unit, LOG_WARNING, filename, line, 0,
                                   "Invalid DHCP option, valid range is 1-65535, ignoring assignment: %s", rvalue);
                        return 0;
                }
        } else {
                r = safe_atou8(word, &u8);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Invalid DHCP option, ignoring assignment: %s", rvalue);
                         return 0;
                }
                if (u8 < 1 || u8 >= UINT8_MAX) {
                        log_syntax(unit, LOG_WARNING, filename, line, 0,
                                   "Invalid DHCP option, valid range is 1-254, ignoring assignment: %s", rvalue);
                        return 0;
                }
        }

        word = mfree(word);
        r = extract_first_word(&p, &word, ":", 0);
        if (r == -ENOMEM)
                return log_oom();
        if (r <= 0 || isempty(p)) {
                log_syntax(unit, LOG_WARNING, filename, line, r,
                           "Invalid DHCP option, ignoring assignment: %s", rvalue);
                return 0;
        }

        type = dhcp_option_data_type_from_string(word);
        if (type < 0) {
                log_syntax(unit, LOG_WARNING, filename, line, 0,
                           "Invalid DHCP option data type, ignoring assignment: %s", p);
                return 0;
        }

        switch(type) {
        case DHCP_OPTION_DATA_UINT8:{
                r = safe_atou8(p, &uint8_data);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to parse DHCP uint8 data, ignoring assignment: %s", p);
                        return 0;
                }

                udata = &uint8_data;
                sz = sizeof(uint8_t);
                break;
        }
        case DHCP_OPTION_DATA_UINT16:{
                r = safe_atou16(p, &uint16_data);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to parse DHCP uint16 data, ignoring assignment: %s", p);
                        return 0;
                }

                udata = &uint16_data;
                sz = sizeof(uint16_t);
                break;
        }
        case DHCP_OPTION_DATA_UINT32: {
                r = safe_atou32(p, &uint32_data);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to parse DHCP uint32 data, ignoring assignment: %s", p);
                        return 0;
                }

                udata = &uint32_data;
                sz = sizeof(uint32_t);

                break;
        }
        case DHCP_OPTION_DATA_IPV4ADDRESS: {
                r = in_addr_from_string(AF_INET, p, &addr);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to parse DHCP ipv4address data, ignoring assignment: %s", p);
                        return 0;
                }

                udata = &addr.in;
                sz = sizeof(addr.in.s_addr);
                break;
        }
        case DHCP_OPTION_DATA_IPV6ADDRESS: {
                r = in_addr_from_string(AF_INET6, p, &addr);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to parse DHCP ipv6address data, ignoring assignment: %s", p);
                        return 0;
                }

                udata = &addr.in6;
                sz = sizeof(addr.in6.s6_addr);
                break;
        }
        case DHCP_OPTION_DATA_STRING:
                sz = cunescape(p, UNESCAPE_ACCEPT_NUL, &q);
                if (sz < 0)
                        log_syntax(unit, LOG_WARNING, filename, line, sz,
                                   "Failed to decode DHCP option data, ignoring assignment: %s", p);

                udata = q;
                break;
        default:
                return -EINVAL;
        }

        if (ltype == AF_INET6) {
                r = sd_dhcp6_option_new(u16, udata, sz, enterprise_identifier, &opt6);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to store DHCP option '%s', ignoring assignment: %m", rvalue);
                        return 0;
                }

                r = ordered_hashmap_ensure_allocated(options, &dhcp6_option_hash_ops);
                if (r < 0)
                        return log_oom();

                /* Overwrite existing option */
                old6 = ordered_hashmap_get(*options, UINT_TO_PTR(u16));
                r = ordered_hashmap_replace(*options, UINT_TO_PTR(u16), opt6);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to store DHCP option '%s', ignoring assignment: %m", rvalue);
                        return 0;
                }
                TAKE_PTR(opt6);
        } else {
                r = sd_dhcp_option_new(u8, udata, sz, &opt4);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to store DHCP option '%s', ignoring assignment: %m", rvalue);
                        return 0;
                }

                r = ordered_hashmap_ensure_allocated(options, &dhcp_option_hash_ops);
                if (r < 0)
                        return log_oom();

                /* Overwrite existing option */
                old4 = ordered_hashmap_get(*options, UINT_TO_PTR(u8));
                r = ordered_hashmap_replace(*options, UINT_TO_PTR(u8), opt4);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to store DHCP option '%s', ignoring assignment: %m", rvalue);
                        return 0;
                }
                TAKE_PTR(opt4);
        }
        return 0;
}

int config_parse_dhcp_request_options(
                const char *unit,
                const char *filename,
                unsigned line,
                const char *section,
                unsigned section_line,
                const char *lvalue,
                int ltype,
                const char *rvalue,
                void *data,
                void *userdata) {

        Network *network = data;
        const char *p;
        int r;

        assert(filename);
        assert(lvalue);
        assert(rvalue);
        assert(data);

        if (isempty(rvalue)) {
                if (ltype == AF_INET)
                        network->dhcp_request_options = set_free(network->dhcp_request_options);
                else
                        network->dhcp6_request_options = set_free(network->dhcp6_request_options);

                return 0;
        }

        for (p = rvalue;;) {
                _cleanup_free_ char *n = NULL;
                uint32_t i;

                r = extract_first_word(&p, &n, NULL, 0);
                if (r == -ENOMEM)
                        return log_oom();
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to parse DHCP request option, ignoring assignment: %s",
                                   rvalue);
                        return 0;
                }
                if (r == 0)
                        return 0;

                r = safe_atou32(n, &i);
                if (r < 0) {
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "DHCP request option is invalid, ignoring assignment: %s", n);
                        continue;
                }

                if (i < 1 || i >= UINT8_MAX) {
                        log_syntax(unit, LOG_WARNING, filename, line, 0,
                                   "DHCP request option is invalid, valid range is 1-254, ignoring assignment: %s", n);
                        continue;
                }

                r = set_ensure_put(ltype == AF_INET ? &network->dhcp_request_options : &network->dhcp6_request_options,
                                   NULL, UINT32_TO_PTR(i));
                if (r < 0)
                        log_syntax(unit, LOG_WARNING, filename, line, r,
                                   "Failed to store DHCP request option '%s', ignoring assignment: %m", n);
        }
}

DEFINE_CONFIG_PARSE_ENUM(config_parse_dhcp_use_domains, dhcp_use_domains, DHCPUseDomains,
                         "Failed to parse DHCP use domains setting");

static const char* const dhcp_use_domains_table[_DHCP_USE_DOMAINS_MAX] = {
        [DHCP_USE_DOMAINS_NO] = "no",
        [DHCP_USE_DOMAINS_ROUTE] = "route",
        [DHCP_USE_DOMAINS_YES] = "yes",
};

DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(dhcp_use_domains, DHCPUseDomains, DHCP_USE_DOMAINS_YES);

static const char * const dhcp_option_data_type_table[_DHCP_OPTION_DATA_MAX] = {
        [DHCP_OPTION_DATA_UINT8]       = "uint8",
        [DHCP_OPTION_DATA_UINT16]      = "uint16",
        [DHCP_OPTION_DATA_UINT32]      = "uint32",
        [DHCP_OPTION_DATA_STRING]      = "string",
        [DHCP_OPTION_DATA_IPV4ADDRESS] = "ipv4address",
        [DHCP_OPTION_DATA_IPV6ADDRESS] = "ipv6address",
};

DEFINE_STRING_TABLE_LOOKUP(dhcp_option_data_type, DHCPOptionDataType);