19520565317

Committed 19 Nov 2025 11:19PM UTC coverage: 72.548% (+0.1%) from 72.449%

Build # 19520565317

Build Type

push

github

Committed by

web-flow

Commit Message

core: Verify inherited FDs are writable for stdout/stderr (#39674)

When inheriting file descriptors for stdout/stderr (either from stdin or
when making stderr inherit from stdout), we previously just assumed they
would be writable and dup'd them. This could lead to broken setups if
the inherited FD was actually opened read-only.

Before dup'ing any inherited FDs to stdout/stderr, verify they are
actually writable using the new fd_is_writable() helper. If not, fall
back to /dev/null (or reopen the terminal in the TTY case) with a
warning, rather than silently creating a broken setup where output
operations would fail.

Run Details

31 of 44 new or added lines in 3 files covered. (70.45%)

813 existing lines in 43 files now uncovered.

308541 of 425291 relevant lines covered (72.55%)

1188151.68 hits per line

Source File
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84.99

/src/network/networkd-link.c

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

#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/if_link.h>
#include <linux/netdevice.h>
#include <net/if.h>
#include <sys/socket.h>
#include <unistd.h>

#include "sd-bus.h"
#include "sd-dhcp-client.h"
#include "sd-dhcp-server.h"
#include "sd-dhcp6-client.h"
#include "sd-dhcp6-lease.h"
#include "sd-ipv4ll.h"
#include "sd-lldp-rx.h"
#include "sd-ndisc.h"
#include "sd-netlink.h"
#include "sd-radv.h"

#include "alloc-util.h"
#include "arphrd-util.h"
#include "bitfield.h"
#include "device-util.h"
#include "dns-domain.h"
#include "errno-util.h"
#include "ethtool-util.h"
#include "event-util.h"
#include "format-ifname.h"
#include "fs-util.h"
#include "glyph-util.h"
#include "logarithm.h"
#include "netif-util.h"
#include "netlink-util.h"
#include "networkd-address.h"
#include "networkd-address-label.h"
#include "networkd-bridge-fdb.h"
#include "networkd-bridge-mdb.h"
#include "networkd-bridge-vlan.h"
#include "networkd-dhcp-prefix-delegation.h"
#include "networkd-dhcp-server.h"
#include "networkd-dhcp4.h"
#include "networkd-dhcp6.h"
#include "networkd-ipv4acd.h"
#include "networkd-ipv4ll.h"
#include "networkd-ipv6-proxy-ndp.h"
#include "networkd-link.h"
#include "networkd-link-bus.h"
#include "networkd-lldp-tx.h"
#include "networkd-manager.h"
#include "networkd-ndisc.h"
#include "networkd-neighbor.h"
#include "networkd-nexthop.h"
#include "networkd-queue.h"
#include "networkd-radv.h"
#include "networkd-resolve-hook.h"
#include "networkd-route.h"
#include "networkd-route-util.h"
#include "networkd-routing-policy-rule.h"
#include "networkd-setlink.h"
#include "networkd-sriov.h"
#include "networkd-state-file.h"
#include "networkd-sysctl.h"
#include "networkd-wifi.h"
#include "ordered-set.h"
#include "parse-util.h"
#include "set.h"
#include "socket-util.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
#include "tc.h"
#include "udev-util.h"

void link_required_operstate_for_online(Link *link, LinkOperationalStateRange *ret) {
        assert(link);
        assert(ret);

        if (link->network && operational_state_range_is_valid(&link->network->required_operstate_for_online))
                /* If explicitly specified, use it as is. */
                *ret = link->network->required_operstate_for_online;
        else if (link->iftype == ARPHRD_CAN)
                /* CAN devices do not support addressing, hence defaults to 'carrier'. */
                *ret = (const LinkOperationalStateRange) {
                        .min = LINK_OPERSTATE_CARRIER,
                        .max = LINK_OPERSTATE_CARRIER,
                };
        else if (link->network && link->network->bond)
                /* Bonding slaves do not support addressing. */
                *ret = (const LinkOperationalStateRange) {
                        .min = LINK_OPERSTATE_ENSLAVED,
                        .max = LINK_OPERSTATE_ENSLAVED,
                };
        else if (STRPTR_IN_SET(link->kind, "batadv", "bond", "bridge", "vrf"))
                /* Some of slave interfaces may be offline. */
                *ret = (const LinkOperationalStateRange) {
                        .min = LINK_OPERSTATE_DEGRADED_CARRIER,
                        .max = LINK_OPERSTATE_ROUTABLE,
                };
        else
                *ret = LINK_OPERSTATE_RANGE_DEFAULT;
}

AddressFamily link_required_family_for_online(Link *link) {
        assert(link);

        if (link->network && link->network->required_family_for_online >= 0)
                return link->network->required_family_for_online;

        if (link->network && operational_state_range_is_valid(&link->network->required_operstate_for_online))
                /* If RequiredForOnline= is explicitly specified, defaults to no. */
                return ADDRESS_FAMILY_NO;

        if (STRPTR_IN_SET(link->kind, "batadv", "bond", "bridge", "vrf"))
                /* As the minimum required operstate for master interfaces is 'degraded-carrier',
                 * we should request an address assigned to the link for backward compatibility. */
                return ADDRESS_FAMILY_YES;

        return ADDRESS_FAMILY_NO;
}

bool link_ipv6_enabled(Link *link) {
        assert(link);

        if (!socket_ipv6_is_supported())
                return false;

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

        if (!link->network)
                return false;

        if (link->network->bond)
                return false;

        if (link_ipv6ll_enabled(link))
                return true;

        if (network_has_static_ipv6_configurations(link->network))
                return true;

        return false;
}

bool link_has_ipv6_connectivity(Link *link) {
        LinkAddressState ipv6_address_state;

        assert(link);

        link_get_address_states(link, NULL, &ipv6_address_state, NULL);

        switch (ipv6_address_state) {
        case LINK_ADDRESS_STATE_ROUTABLE:
                /* If the interface has a routable IPv6 address, then we assume yes. */
                return true;

        case LINK_ADDRESS_STATE_DEGRADED:
                /* If the interface has only degraded IPv6 address (mostly, link-local address), then let's check
                 * there is an IPv6 default gateway. */
                return link_has_default_gateway(link, AF_INET6);

        case LINK_ADDRESS_STATE_OFF:
                /* No IPv6 address. */
                return false;

        default:
                assert_not_reached();
        }
}

static bool link_is_ready_to_configure_one(Link *link, bool allow_unmanaged) {
        assert(link);

        if (!IN_SET(link->state, LINK_STATE_CONFIGURING, LINK_STATE_CONFIGURED, LINK_STATE_UNMANAGED))
                return false;

        if (!link->network)
                return allow_unmanaged;

        if (!link->network->configure_without_carrier) {
                if (link->set_flags_messages > 0)
                        return false;

                if (!link_has_carrier(link))
                        return false;
        }

        if (link->set_link_messages > 0)
                return false;

        if (!link->activated)
                return false;

        return true;
}

bool link_is_ready_to_configure(Link *link, bool allow_unmanaged) {
        return check_ready_for_all_sr_iov_ports(link, allow_unmanaged, link_is_ready_to_configure_one);
}

bool link_is_ready_to_configure_by_name(Manager *manager, const char *name, bool allow_unmanaged) {
        assert(manager);
        assert(name);

        Link *link;
        if (link_get_by_name(manager, name, &link) < 0)
                return false;

        return link_is_ready_to_configure(link, allow_unmanaged);
}

void link_ntp_settings_clear(Link *link) {
        link->ntp = strv_free(link->ntp);
}

void link_dns_settings_clear(Link *link) {
        if (link->n_dns != UINT_MAX)
                for (unsigned i = 0; i < link->n_dns; i++)
                        in_addr_full_free(link->dns[i]);
        link->dns = mfree(link->dns);
        link->n_dns = UINT_MAX;

        link->search_domains = ordered_set_free(link->search_domains);
        link->route_domains = ordered_set_free(link->route_domains);

        link->dns_default_route = -1;
        link->llmnr = _RESOLVE_SUPPORT_INVALID;
        link->mdns = _RESOLVE_SUPPORT_INVALID;
        link->dnssec_mode = _DNSSEC_MODE_INVALID;
        link->dns_over_tls_mode = _DNS_OVER_TLS_MODE_INVALID;

        link->dnssec_negative_trust_anchors = set_free(link->dnssec_negative_trust_anchors);
}

static void link_free_engines(Link *link) {
        if (!link)
                return;

        link->dhcp_server = sd_dhcp_server_unref(link->dhcp_server);

        link->dhcp_client = sd_dhcp_client_unref(link->dhcp_client);
        link->dhcp_lease = sd_dhcp_lease_unref(link->dhcp_lease);
        link->dhcp4_6rd_tunnel_name = mfree(link->dhcp4_6rd_tunnel_name);

        link->lldp_rx = sd_lldp_rx_unref(link->lldp_rx);
        link->lldp_tx = sd_lldp_tx_unref(link->lldp_tx);

        link->ipv4acd_by_address = hashmap_free(link->ipv4acd_by_address);

        link->ipv4ll = sd_ipv4ll_unref(link->ipv4ll);

        link->dhcp6_client = sd_dhcp6_client_unref(link->dhcp6_client);
        link->dhcp6_lease = sd_dhcp6_lease_unref(link->dhcp6_lease);

        link->ndisc = sd_ndisc_unref(link->ndisc);
        link->ndisc_expire = sd_event_source_disable_unref(link->ndisc_expire);
        ndisc_flush(link);

        link->radv = sd_radv_unref(link->radv);
}

static Link* link_free(Link *link) {
        assert(link);

        (void) link_clear_sysctl_shadows(link);

        link_ntp_settings_clear(link);
        link_dns_settings_clear(link);

        link->neighbors = set_free(link->neighbors);
        link->addresses = set_free(link->addresses);
        link->qdiscs = set_free(link->qdiscs);
        link->tclasses = set_free(link->tclasses);

        link->dhcp_pd_prefixes = set_free(link->dhcp_pd_prefixes);

        link_free_engines(link);

        set_free(link->sr_iov_virt_port_ifindices);
        free(link->ifname);
        strv_free(link->alternative_names);
        free(link->kind);
        free(link->ssid);
        free(link->previous_ssid);
        free(link->driver);

        unlink_and_free(link->lease_file);
        unlink_and_free(link->state_file);

        sd_device_unref(link->dev);
        netdev_unref(link->netdev);

        hashmap_free(link->bound_to_links);
        hashmap_free(link->bound_by_links);

        set_free(link->slaves);

        network_unref(link->network);

        sd_event_source_disable_unref(link->carrier_lost_timer);
        sd_event_source_disable_unref(link->ipv6_mtu_wait_synced_event_source);

        return mfree(link);
}

DEFINE_TRIVIAL_REF_UNREF_FUNC(Link, link, link_free);

DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
                link_hash_ops,
                void, trivial_hash_func, trivial_compare_func,
                Link, link_unref);

int link_get_by_index(Manager *m, int ifindex, Link **ret) {
        Link *link;

        assert(m);

        if (ifindex <= 0)
                return -EINVAL;

        link = hashmap_get(m->links_by_index, INT_TO_PTR(ifindex));
        if (!link)
                return -ENODEV;

        if (ret)
                *ret = link;
        return 0;
}

int link_get_by_name(Manager *m, const char *ifname, Link **ret) {
        Link *link;

        assert(m);
        assert(ifname);

        link = hashmap_get(m->links_by_name, ifname);
        if (!link)
                return -ENODEV;

        if (ret)
                *ret = link;
        return 0;
}

int link_get_by_hw_addr(Manager *m, const struct hw_addr_data *hw_addr, Link **ret) {
        Link *link;

        assert(m);
        assert(hw_addr);

        link = hashmap_get(m->links_by_hw_addr, hw_addr);
        if (!link)
                return -ENODEV;

        if (ret)
                *ret = link;
        return 0;
}

int link_get_master(Link *link, Link **ret) {
        assert(link);
        assert(link->manager);
        assert(ret);

        if (link->master_ifindex <= 0 || link->master_ifindex == link->ifindex)
                return -ENODEV;

        return link_get_by_index(link->manager, link->master_ifindex, ret);
}

void link_set_state(Link *link, LinkState state) {
        assert(link);

        if (link->state == state)
                return;

        log_link_debug(link, "State changed: %s -> %s",
                       link_state_to_string(link->state),
                       link_state_to_string(state));

        link->state = state;

        link_send_changed(link, "AdministrativeState");
        link_dirty(link);
}

int link_stop_engines(Link *link, bool may_keep_dynamic) {
        int r, ret = 0;

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

        bool keep_dynamic =
                may_keep_dynamic &&
                link->network &&
                (link->manager->state == MANAGER_RESTARTING ||
                 FLAGS_SET(link->network->keep_configuration, KEEP_CONFIGURATION_DYNAMIC_ON_STOP));

        if (!keep_dynamic) {
                r = sd_dhcp_client_stop(link->dhcp_client);
                if (r < 0)
                        RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop DHCPv4 client: %m"));

                r = sd_ipv4ll_stop(link->ipv4ll);
                if (r < 0)
                        RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop IPv4 link-local: %m"));

                r = sd_dhcp6_client_stop(link->dhcp6_client);
                if (r < 0)
                        RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop DHCPv6 client: %m"));

                r = dhcp_pd_remove(link, /* only_marked = */ false);
                if (r < 0)
                        RET_GATHER(ret, log_link_warning_errno(link, r, "Could not remove DHCPv6 PD addresses and routes: %m"));

                r = ndisc_stop(link);
                if (r < 0)
                        RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop IPv6 Router Discovery: %m"));

                ndisc_flush(link);
        }

        r = sd_dhcp_server_stop(link->dhcp_server);
        if (r < 0)
                RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop DHCPv4 server: %m"));

        r = sd_lldp_rx_stop(link->lldp_rx);
        if (r < 0)
                RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop LLDP Rx: %m"));

        r = sd_lldp_tx_stop(link->lldp_tx);
        if (r < 0)
                RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop LLDP Tx: %m"));

        r = ipv4acd_stop(link);
        if (r < 0)
                RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop IPv4 ACD client: %m"));

        r = sd_radv_stop(link->radv);
        if (r < 0)
                RET_GATHER(ret, log_link_warning_errno(link, r, "Could not stop IPv6 Router Advertisement: %m"));

        return ret;
}

void link_enter_failed(Link *link) {
        assert(link);

        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
                return;

        log_link_warning(link, "Failed");

        link_set_state(link, LINK_STATE_FAILED);

        if (!ratelimit_below(&link->automatic_reconfigure_ratelimit)) {
                log_link_warning(link, "The interface entered the failed state frequently, refusing to reconfigure it automatically.");
                goto stop;
        }

        log_link_info(link, "Trying to reconfigure the interface.");
        if (link_reconfigure(link, LINK_RECONFIGURE_UNCONDITIONALLY) > 0)
                return;

stop:
        (void) link_stop_engines(link, /* may_keep_dynamic = */ false);
}

void link_check_ready(Link *link) {
        Address *a;

        assert(link);

        if (link->state == LINK_STATE_CONFIGURED)
                return;

        if (link->state != LINK_STATE_CONFIGURING)
                return (void) log_link_debug(link, "%s(): link is in %s state.", __func__, link_state_to_string(link->state));

        if (!link->network)
                return (void) log_link_debug(link, "%s(): link is unmanaged.", __func__);

        if (!link->tc_configured)
                return (void) log_link_debug(link, "%s(): traffic controls are not configured.", __func__);

        if (link->set_link_messages > 0)
                return (void) log_link_debug(link, "%s(): link layer is configuring.", __func__);

        if (!link->activated)
                return (void) log_link_debug(link, "%s(): link is not activated.", __func__);

        if (link->iftype == ARPHRD_CAN)
                /* let's shortcut things for CAN which doesn't need most of checks below. */
                goto ready;

        if (!link->stacked_netdevs_created)
                return (void) log_link_debug(link, "%s(): stacked netdevs are not created.", __func__);

        if (!link->static_addresses_configured)
                return (void) log_link_debug(link, "%s(): static addresses are not configured.", __func__);

        if (!link->static_address_labels_configured)
                return (void) log_link_debug(link, "%s(): static address labels are not configured.", __func__);

        if (!link->static_bridge_fdb_configured)
                return (void) log_link_debug(link, "%s(): static bridge MDB entries are not configured.", __func__);

        if (!link->static_bridge_mdb_configured)
                return (void) log_link_debug(link, "%s(): static bridge MDB entries are not configured.", __func__);

        if (!link->static_ipv6_proxy_ndp_configured)
                return (void) log_link_debug(link, "%s(): static IPv6 proxy NDP addresses are not configured.", __func__);

        if (!link->static_neighbors_configured)
                return (void) log_link_debug(link, "%s(): static neighbors are not configured.", __func__);

        if (!link->static_nexthops_configured)
                return (void) log_link_debug(link, "%s(): static nexthops are not configured.", __func__);

        if (!link->static_routes_configured)
                return (void) log_link_debug(link, "%s(): static routes are not configured.", __func__);

        if (!link->static_routing_policy_rules_configured)
                return (void) log_link_debug(link, "%s(): static routing policy rules are not configured.", __func__);

        if (!link->sr_iov_configured)
                return (void) log_link_debug(link, "%s(): SR-IOV is not configured.", __func__);

        /* IPv6LL is assigned after the link gains its carrier. */
        if (!link->network->configure_without_carrier &&
            link_ipv6ll_enabled(link) &&
            !in6_addr_is_set(&link->ipv6ll_address))
                return (void) log_link_debug(link, "%s(): IPv6LL is not configured yet.", __func__);

        /* All static addresses must be ready. */
        bool has_static_address = false;
        SET_FOREACH(a, link->addresses) {
                if (a->source != NETWORK_CONFIG_SOURCE_STATIC)
                        continue;
                if (!address_is_ready(a))
                        return (void) log_link_debug(link, "%s(): static address %s is not ready.", __func__,
                                                     IN_ADDR_PREFIX_TO_STRING(a->family, &a->in_addr, a->prefixlen));
                has_static_address = true;
        }

        /* If at least one static address is requested, do not request that dynamic addressing protocols are finished. */
        if (has_static_address)
                goto ready;

        /* If no dynamic addressing protocol enabled, assume the interface is ready.
         * Note, ignore NDisc when ConfigureWithoutCarrier= is enabled, as IPv6AcceptRA= is enabled by default. */
        if (!link_ipv4ll_enabled(link) && !link_dhcp4_enabled(link) &&
            !link_dhcp6_enabled(link) && !link_dhcp_pd_is_enabled(link) &&
            (link->network->configure_without_carrier || !link_ndisc_enabled(link)))
                goto ready;

        bool ipv4ll_ready =
                link_ipv4ll_enabled(link) && link->ipv4ll_address_configured &&
                link_check_addresses_ready(link, NETWORK_CONFIG_SOURCE_IPV4LL);
        bool dhcp4_ready =
                link_dhcp4_enabled(link) && link->dhcp4_configured &&
                link_check_addresses_ready(link, NETWORK_CONFIG_SOURCE_DHCP4);
        bool dhcp6_ready =
                link_dhcp6_enabled(link) && link->dhcp6_configured &&
                (!link->network->dhcp6_use_address ||
                 link_check_addresses_ready(link, NETWORK_CONFIG_SOURCE_DHCP6));
        bool dhcp_pd_ready =
                link_dhcp_pd_is_enabled(link) && link->dhcp_pd_configured &&
                (!link->network->dhcp_pd_assign ||
                 link_check_addresses_ready(link, NETWORK_CONFIG_SOURCE_DHCP_PD));
        bool ndisc_ready =
                link_ndisc_enabled(link) && link->ndisc_configured &&
                (!link->network->ndisc_use_autonomous_prefix ||
                 link_check_addresses_ready(link, NETWORK_CONFIG_SOURCE_NDISC));

        /* If the uplink for PD is self, then request the corresponding DHCP protocol is also ready. */
        if (dhcp_pd_is_uplink(link, link, /* accept_auto = */ false)) {
                if (link_dhcp4_enabled(link) && link->network->dhcp_use_6rd &&
                    sd_dhcp_lease_has_6rd(link->dhcp_lease)) {
                        if (!link->dhcp4_configured)
                                return (void) log_link_debug(link, "%s(): DHCPv4 6rd prefix is assigned, but DHCPv4 protocol is not finished yet.", __func__);
                        if (!dhcp_pd_ready)
                                return (void) log_link_debug(link, "%s(): DHCPv4 is finished, but prefix acquired by DHCPv4-6rd is not assigned yet.", __func__);
                }

                if (link_dhcp6_enabled(link) && link->network->dhcp6_use_pd_prefix &&
                    sd_dhcp6_lease_has_pd_prefix(link->dhcp6_lease)) {
                        if (!link->dhcp6_configured)
                                return (void) log_link_debug(link, "%s(): DHCPv6 IA_PD prefix is assigned, but DHCPv6 protocol is not finished yet.", __func__);
                        if (!dhcp_pd_ready)
                                return (void) log_link_debug(link, "%s(): DHCPv6 is finished, but prefix acquired by DHCPv6 IA_PD is not assigned yet.", __func__);
                }
        }

        /* At least one dynamic addressing protocol is finished. */
        if (!ipv4ll_ready && !dhcp4_ready && !dhcp6_ready && !dhcp_pd_ready && !ndisc_ready)
                return (void) log_link_debug(link, "%s(): dynamic addressing protocols are enabled but none of them finished yet.", __func__);

        log_link_debug(link, "%s(): IPv4LL:%s DHCPv4:%s DHCPv6:%s DHCP-PD:%s NDisc:%s",
                       __func__,
                       yes_no(ipv4ll_ready),
                       yes_no(dhcp4_ready),
                       yes_no(dhcp6_ready),
                       yes_no(dhcp_pd_ready),
                       yes_no(ndisc_ready));

ready:
        link_set_state(link, LINK_STATE_CONFIGURED);
}

static int link_request_static_configs(Link *link) {
        int r;

        assert(link);
        assert(link->network);
        assert(link->state != _LINK_STATE_INVALID);

        r = link_request_static_addresses(link);
        if (r < 0)
                return r;

        r = link_request_static_address_labels(link);
        if (r < 0)
                return r;

        r = link_request_static_bridge_fdb(link);
        if (r < 0)
                return r;

        r = link_request_static_bridge_mdb(link);
        if (r < 0)
                return r;

        r = link_request_static_ipv6_proxy_ndp_addresses(link);
        if (r < 0)
                return r;

        r = link_request_static_neighbors(link);
        if (r < 0)
                return r;

        r = link_request_static_nexthops(link, false);
        if (r < 0)
                return r;

        r = link_request_static_routes(link, false);
        if (r < 0)
                return r;

        r = link_request_static_routing_policy_rules(link);
        if (r < 0)
                return r;

        return 0;
}

int link_request_stacked_netdevs(Link *link, NetDevLocalAddressType type) {
        NetDev *netdev;
        int r;

        assert(link);

        if (!IN_SET(link->state, LINK_STATE_CONFIGURING, LINK_STATE_CONFIGURED))
                return 0;

        assert(link->network);

        link->stacked_netdevs_created = false;

        HASHMAP_FOREACH(netdev, link->network->stacked_netdevs) {
                if (!netdev_needs_reconfigure(netdev, type))
                        continue;

                r = link_request_stacked_netdev(link, netdev);
                if (r < 0)
                        return r;
        }

        if (link->create_stacked_netdev_messages == 0) {
                link->stacked_netdevs_created = true;
                link_check_ready(link);
        }

        return 0;
}

static int link_acquire_dynamic_ipv6_conf(Link *link) {
        int r;

        assert(link);

        r = radv_start(link);
        if (r < 0)
                return log_link_warning_errno(link, r, "Failed to start IPv6 Router Advertisement engine: %m");

        r = ndisc_start(link);
        if (r < 0)
                return log_link_warning_errno(link, r, "Failed to start IPv6 Router Discovery: %m");

        r = dhcp6_start(link);
        if (r < 0)
                return log_link_warning_errno(link, r, "Failed to start DHCPv6 client: %m");

        return 0;
}

static int link_acquire_dynamic_ipv4_conf(Link *link) {
        int r;

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

        if (link->dhcp_client) {
                r = dhcp4_start(link);
                if (r < 0)
                        return log_link_warning_errno(link, r, "Failed to start DHCPv4 client: %m");

                log_link_debug(link, "Acquiring DHCPv4 lease.");

        } else if (link->ipv4ll) {
                if (in4_addr_is_set(&link->network->ipv4ll_start_address)) {
                        r = sd_ipv4ll_set_address(link->ipv4ll, &link->network->ipv4ll_start_address);
                        if (r < 0)
                                return log_link_warning_errno(link, r, "Could not set IPv4 link-local start address: %m");
                }

                r = ipv4ll_start(link);
                if (r < 0)
                        return log_link_warning_errno(link, r, "Could not acquire IPv4 link-local address: %m");
                if (r > 0)
                        log_link_debug(link, "Acquiring IPv4 link-local address.");
        }

        r = link_start_dhcp4_server(link);
        if (r < 0)
                return log_link_warning_errno(link, r, "Could not start DHCP server: %m");

        r = ipv4acd_start(link);
        if (r < 0)
                return log_link_warning_errno(link, r, "Could not start IPv4 ACD client: %m");

        return 0;
}

static int link_acquire_dynamic_conf(Link *link) {
        int r;

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

        r = link_acquire_dynamic_ipv4_conf(link);
        if (r < 0)
                return r;

        if (in6_addr_is_set(&link->ipv6ll_address)) {
                r = link_acquire_dynamic_ipv6_conf(link);
                if (r < 0)
                        return r;
        }

        if (!link_radv_enabled(link) || !link->network->dhcp_pd_announce) {
                /* DHCPv6PD downstream does not require IPv6LL address. But may require RADV to be
                 * configured, and RADV may not be configured yet here. Only acquire subnet prefix when
                 * RADV is disabled, or the announcement of the prefix is disabled. Otherwise, the
                 * below will be called in radv_start(). */
                r = dhcp_request_prefix_delegation(link);
                if (r < 0)
                        return log_link_warning_errno(link, r, "Failed to request DHCP delegated subnet prefix: %m");
        }

        if (link->lldp_tx) {
                r = sd_lldp_tx_start(link->lldp_tx);
                if (r < 0)
                        return log_link_warning_errno(link, r, "Failed to start LLDP transmission: %m");
        }

        if (link->lldp_rx) {
                r = sd_lldp_rx_start(link->lldp_rx);
                if (r < 0)
                        return log_link_warning_errno(link, r, "Failed to start LLDP client: %m");
        }

        return 0;
}

int link_ipv6ll_gained(Link *link) {
        int r;

        assert(link);

        log_link_info(link, "Gained IPv6LL");

        if (!IN_SET(link->state, LINK_STATE_CONFIGURING, LINK_STATE_CONFIGURED))
                return 0;

        r = link_acquire_dynamic_ipv6_conf(link);
        if (r < 0)
                return r;

        r = link_request_stacked_netdevs(link, NETDEV_LOCAL_ADDRESS_IPV6LL);
        if (r < 0)
                return r;

        link_check_ready(link);
        return 0;
}

int link_handle_bound_to_list(Link *link) {
        bool required_up = false;
        bool link_is_up = false;
        Link *l;

        assert(link);

        /* If at least one interface in bound_to_links has carrier, then make this interface up.
         * If all interfaces in bound_to_links do not, then make this interface down. */

        if (hashmap_isempty(link->bound_to_links))
                return 0;

        if (link->flags & IFF_UP)
                link_is_up = true;

        HASHMAP_FOREACH(l, link->bound_to_links)
                if (link_has_carrier(l)) {
                        required_up = true;
                        break;
                }

        if (!required_up && link_is_up)
                return link_request_to_bring_up_or_down(link, /* up = */ false);
        if (required_up && !link_is_up)
                return link_request_to_bring_up_or_down(link, /* up = */ true);

        return 0;
}

static int link_handle_bound_by_list(Link *link) {
        Link *l;
        int r;

        assert(link);

        /* Update up or down state of interfaces which depend on this interface's carrier state. */

        HASHMAP_FOREACH(l, link->bound_by_links) {
                r = link_handle_bound_to_list(l);
                if (r < 0)
                        return r;
        }

        return 0;
}

static int link_put_carrier(Link *link, Link *carrier, Hashmap **h) {
        int r;

        assert(link);
        assert(carrier);

        if (link == carrier)
                return 0;

        if (hashmap_get(*h, INT_TO_PTR(carrier->ifindex)))
                return 0;

        r = hashmap_ensure_put(h, NULL, INT_TO_PTR(carrier->ifindex), carrier);
        if (r < 0)
                return r;

        link_dirty(link);

        return 0;
}

static int link_new_bound_by_list(Link *link) {
        Manager *m;
        Link *carrier;
        int r;

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

        m = link->manager;

        HASHMAP_FOREACH(carrier, m->links_by_index) {
                if (!carrier->network)
                        continue;

                if (strv_isempty(carrier->network->bind_carrier))
                        continue;

                if (strv_fnmatch(carrier->network->bind_carrier, link->ifname)) {
                        r = link_put_carrier(link, carrier, &link->bound_by_links);
                        if (r < 0)
                                return r;
                }
        }

        HASHMAP_FOREACH(carrier, link->bound_by_links) {
                r = link_put_carrier(carrier, link, &carrier->bound_to_links);
                if (r < 0)
                        return r;
        }

        return 0;
}

static int link_new_bound_to_list(Link *link) {
        Manager *m;
        Link *carrier;
        int r;

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

        if (!link->network)
                return 0;

        if (strv_isempty(link->network->bind_carrier))
                return 0;

        m = link->manager;

        HASHMAP_FOREACH(carrier, m->links_by_index) {
                if (strv_fnmatch(link->network->bind_carrier, carrier->ifname)) {
                        r = link_put_carrier(link, carrier, &link->bound_to_links);
                        if (r < 0)
                                return r;
                }
        }

        HASHMAP_FOREACH(carrier, link->bound_to_links) {
                r = link_put_carrier(carrier, link, &carrier->bound_by_links);
                if (r < 0)
                        return r;
        }

        return 0;
}

static void link_free_bound_to_list(Link *link) {
        bool updated = false;
        Link *bound_to;

        assert(link);

        while ((bound_to = hashmap_steal_first(link->bound_to_links))) {
                updated = true;

                if (hashmap_remove(bound_to->bound_by_links, INT_TO_PTR(link->ifindex)))
                        link_dirty(bound_to);
        }

        if (updated)
                link_dirty(link);
}

static void link_free_bound_by_list(Link *link) {
        bool updated = false;
        Link *bound_by;

        assert(link);

        while ((bound_by = hashmap_steal_first(link->bound_by_links))) {
                updated = true;

                if (hashmap_remove(bound_by->bound_to_links, INT_TO_PTR(link->ifindex))) {
                        link_dirty(bound_by);
                        link_handle_bound_to_list(bound_by);
                }
        }

        if (updated)
                link_dirty(link);
}

static int link_append_to_master(Link *link) {
        Link *master;
        int r;

        assert(link);

        /* - The link may have no master.
         * - RTM_NEWLINK message about master interface may not be received yet. */
        if (link_get_master(link, &master) < 0)
                return 0;

        r = set_ensure_put(&master->slaves, &link_hash_ops, link);
        if (r <= 0)
                return r;

        link_ref(link);
        return 0;
}

static void link_drop_from_master(Link *link) {
        Link *master;

        assert(link);

        if (!link->manager)
                return;

        if (link_get_master(link, &master) < 0)
                return;

        link_unref(set_remove(master->slaves, link));
}

static int link_drop_requests(Link *link) {
        Request *req;
        int ret = 0;

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

        ORDERED_SET_FOREACH(req, link->manager->request_queue) {
                if (req->link != link)
                        continue;

                /* If the request is already called, but its reply is not received, then we need to
                 * drop the configuration (e.g. address) here. Note, if the configuration is known,
                 * it will be handled later by link_drop_unmanaged_addresses() or so. */
                if (req->waiting_reply && link->state != LINK_STATE_LINGER)
                        switch (req->type) {
                        case REQUEST_TYPE_ADDRESS: {
                                Address *address = ASSERT_PTR(req->userdata);

                                if (address_get(link, address, NULL) < 0)
                                        RET_GATHER(ret, address_remove(address, link));
                                break;
                        }
                        case REQUEST_TYPE_NEIGHBOR: {
                                Neighbor *neighbor = ASSERT_PTR(req->userdata);

                                if (neighbor_get(link, neighbor, NULL) < 0)
                                        RET_GATHER(ret, neighbor_remove(neighbor, link));
                                break;
                        }
                        case REQUEST_TYPE_NEXTHOP: {
                                NextHop *nexthop = ASSERT_PTR(req->userdata);

                                if (nexthop_get_by_id(link->manager, nexthop->id, NULL) < 0)
                                        RET_GATHER(ret, nexthop_remove(nexthop, link->manager));
                                break;
                        }
                        case REQUEST_TYPE_ROUTE: {
                                Route *route = ASSERT_PTR(req->userdata);

                                if (route_get(link->manager, route, NULL) < 0)
                                        RET_GATHER(ret, route_remove(route, link->manager));
                                break;
                        }
                        default:
                                ;
                        }

                request_detach(req);
        }

        return ret;
}

static Link *link_drop(Link *link) {
        if (!link)
                return NULL;

        assert(link->manager);

        bool notify = link_has_local_lease_domain(link);

        link_set_state(link, LINK_STATE_LINGER);

        /* Drop all references from other links and manager. Note that async netlink calls may have
         * references to the link, and they will be dropped when we receive replies. */

        (void) link_drop_requests(link);

        link_free_bound_to_list(link);
        link_free_bound_by_list(link);

        link_clear_sr_iov_ifindices(link);

        link_drop_from_master(link);

        if (link->state_file)
                (void) unlink(link->state_file);

        link_clean(link);

        STRV_FOREACH(n, link->alternative_names)
                hashmap_remove(link->manager->links_by_name, *n);
        hashmap_remove(link->manager->links_by_name, link->ifname);

        /* bonding master and its slaves have the same hardware address. */
        hashmap_remove_value(link->manager->links_by_hw_addr, &link->hw_addr, link);

        /* The following must be called at last. */
        assert_se(hashmap_remove(link->manager->links_by_index, INT_TO_PTR(link->ifindex)) == link);

        if (notify)
                manager_notify_hook_filters(link->manager);

        return link_unref(link);
}

static int link_drop_unmanaged_config(Link *link) {
        int r;

        assert(link);
        assert(link->state == LINK_STATE_CONFIGURING);
        assert(link->manager);

        r = link_drop_unmanaged_routes(link);
        RET_GATHER(r, link_drop_unmanaged_nexthops(link));
        RET_GATHER(r, link_drop_unmanaged_addresses(link));
        RET_GATHER(r, link_drop_unmanaged_neighbors(link));
        RET_GATHER(r, link_drop_unmanaged_routing_policy_rules(link));

        return r;
}

static int link_drop_static_config(Link *link) {
        int r;

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

        r = link_drop_static_routes(link);
        RET_GATHER(r, link_drop_static_nexthops(link));
        RET_GATHER(r, link_drop_static_addresses(link));
        RET_GATHER(r, link_drop_static_neighbors(link));
        RET_GATHER(r, link_drop_static_routing_policy_rules(link));

        return r;
}

static int link_drop_dynamic_config(Link *link, Network *network) {
        int r;

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

        /* Drop unnecessary dynamic configurations gracefully, e.g. drop DHCP lease in the case that
         * previously DHCP=yes and now DHCP=no, but keep DHCP lease when DHCP setting is unchanged. */

        r = link_drop_ndisc_config(link, network);
        RET_GATHER(r, link_drop_radv_config(link, network)); /* Stop before dropping DHCP-PD prefixes. */
        RET_GATHER(r, link_drop_ipv4ll_config(link, network)); /* Stop before DHCPv4 client. */
        RET_GATHER(r, link_drop_dhcp4_config(link, network));
        RET_GATHER(r, link_drop_dhcp6_config(link, network));
        RET_GATHER(r, link_drop_dhcp_pd_config(link, network));
        link->dhcp_server = sd_dhcp_server_unref(link->dhcp_server);
        link->lldp_rx = sd_lldp_rx_unref(link->lldp_rx); /* TODO: keep the received neighbors. */
        link->lldp_tx = sd_lldp_tx_unref(link->lldp_tx);

        /* Even if we do not release DHCP lease or so, reset 'configured' flags. Otherwise, e.g. if
         * previously UseDNS= was disabled but is now enabled, link will enter configured state before
         * expected DNS servers being acquired. */
        link->ipv4ll_address_configured = false;
        link->dhcp4_configured = false;
        link->dhcp6_configured = false;
        link->dhcp_pd_configured = false;
        link->ndisc_configured = false;

        return r;
}

static int link_configure(Link *link) {
        int r;

        assert(link);
        assert(link->network);
        assert(link->state == LINK_STATE_INITIALIZED);

        link_set_state(link, LINK_STATE_CONFIGURING);

        r = link_drop_unmanaged_config(link);
        if (r < 0)
                return r;

        r = link_new_bound_to_list(link);
        if (r < 0)
                return r;

        r = link_request_traffic_control(link);
        if (r < 0)
                return r;

        r = link_configure_mtu(link);
        if (r < 0)
                return r;

        if (link->iftype == ARPHRD_CAN) {
                /* let's shortcut things for CAN which doesn't need most of what's done below. */
                r = link_request_to_set_can(link);
                if (r < 0)
                        return r;

                return link_request_to_activate(link);
        }

        r = link_request_sr_iov_vfs(link);
        if (r < 0)
                return r;

        r = link_set_sysctl(link);
        if (r < 0)
                return r;

        r = link_request_to_set_mac(link, /* allow_retry = */ true);
        if (r < 0)
                return r;

        r = link_request_to_set_ipoib(link);
        if (r < 0)
                return r;

        r = link_request_to_set_flags(link);
        if (r < 0)
                return r;

        r = link_request_to_set_group(link);
        if (r < 0)
                return r;

        r = link_request_to_set_addrgen_mode(link);
        if (r < 0)
                return r;

        r = link_request_to_set_master(link);
        if (r < 0)
                return r;

        r = link_request_stacked_netdevs(link, _NETDEV_LOCAL_ADDRESS_TYPE_INVALID);
        if (r < 0)
                return r;

        r = link_request_to_set_bond(link);
        if (r < 0)
                return r;

        r = link_request_to_set_bridge(link);
        if (r < 0)
                return r;

        r = link_request_to_set_bridge_vlan(link);
        if (r < 0)
                return r;

        r = link_request_to_activate(link);
        if (r < 0)
                return r;

        r = ipv4ll_configure(link);
        if (r < 0)
                return r;

        r = link_request_dhcp4_client(link);
        if (r < 0)
                return r;

        r = link_request_dhcp6_client(link);
        if (r < 0)
                return r;

        r = link_request_ndisc(link);
        if (r < 0)
                return r;

        r = link_request_dhcp_server(link);
        if (r < 0)
                return r;

        r = link_request_radv(link);
        if (r < 0)
                return r;

        r = link_lldp_rx_configure(link);
        if (r < 0)
                return r;

        r = link_lldp_tx_configure(link);
        if (r < 0)
                return r;

        r = link_request_static_configs(link);
        if (r < 0)
                return r;

        if (!link_has_carrier(link))
                return 0;

        return link_acquire_dynamic_conf(link);
}

static int link_get_network(Link *link, Network **ret) {
        Network *network;
        int r;

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

        ORDERED_HASHMAP_FOREACH(network, link->manager->networks) {
                bool warn = false;

                r = net_match_config(
                                &network->match,
                                link->dev,
                                &link->hw_addr,
                                &link->permanent_hw_addr,
                                link->driver,
                                link->iftype,
                                link->kind,
                                link->ifname,
                                link->alternative_names,
                                link->wlan_iftype,
                                link->ssid,
                                &link->bssid);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                if (network->match.ifname && link->dev) {
                        uint8_t name_assign_type = NET_NAME_UNKNOWN;
                        const char *attr;

                        if (sd_device_get_sysattr_value(link->dev, "name_assign_type", &attr) >= 0)
                                (void) safe_atou8(attr, &name_assign_type);

                        warn = name_assign_type == NET_NAME_ENUM;
                }

                log_link_full(link, warn ? LOG_WARNING : LOG_DEBUG,
                              "Found matching .network file%s: %s",
                              warn ? ", based on potentially unpredictable interface name" : "",
                              network->filename);

                if (network->unmanaged)
                        return -ENOENT;

                *ret = network;
                return 0;
        }

        return log_link_debug_errno(link, SYNTHETIC_ERRNO(ENOENT), "No matching .network found.");
}

static void link_enter_unmanaged(Link *link) {
        assert(link);

        if (link->state == LINK_STATE_UNMANAGED)
                return;

        bool notify = link_has_local_lease_domain(link);

        log_link_full(link, link->state == LINK_STATE_INITIALIZED ? LOG_DEBUG : LOG_INFO,
                      "Unmanaging interface.");

        (void) link_stop_engines(link, /* may_keep_dynamic = */ false);
        (void) link_drop_requests(link);
        (void) link_drop_static_config(link);

        /* The bound_to map depends on .network file, hence it needs to be freed. But, do not free the
         * bound_by map. Otherwise, if a link enters unmanaged state below, then its carrier state will
         * not propagated to other interfaces anymore. Moreover, it is not necessary to recreate the
         * map here, as it depends on .network files assigned to other links. */
        link_free_bound_to_list(link);
        link_free_engines(link);

        link->network = network_unref(link->network);
        link_set_state(link, LINK_STATE_UNMANAGED);

        if (notify)
                manager_notify_hook_filters(link->manager);
}

static int link_managed_by_us(Link *link) {
        int r;

        assert(link);

        if (!link->dev)
                return true;

        const char *s;
        r = sd_device_get_property_value(link->dev, "ID_NET_MANAGED_BY", &s);
        if (r == -ENOENT)
                return true;
        if (r < 0)
                return log_link_warning_errno(link, r, "Failed to get ID_NET_MANAGED_BY udev property: %m");

        if (streq(s, "io.systemd.Network"))
                return true;

        if (link->state == LINK_STATE_UNMANAGED)
                return false; /* Already in unmanaged state */

        log_link_debug(link, "Interface is requested to be managed by '%s', unmanaging the interface.", s);
        link_set_state(link, LINK_STATE_UNMANAGED);
        return false;
}

int link_reconfigure_impl(Link *link, LinkReconfigurationFlag flags) {
        Network *network = NULL;
        int r;

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

        link_assign_netdev(link);

        if (link->manager->state != MANAGER_RUNNING)
                return 0;

        if (IN_SET(link->state, LINK_STATE_PENDING, LINK_STATE_LINGER))
                return 0;

        r = link_managed_by_us(link);
        if (r <= 0)
                return r;

        r = link_get_network(link, &network);
        if (r == -ENOENT) {
                link_enter_unmanaged(link);
                return 0;
        }
        if (r < 0)
                return r;

        if (link->network == network && !FLAGS_SET(flags, LINK_RECONFIGURE_UNCONDITIONALLY))
                return 0;

        _cleanup_free_ char *joined = strv_join(network->dropins, ", ");
        if (link->network)
                log_link_info(link, "Reconfiguring with %s%s%s%s.",
                              network->filename,
                              isempty(joined) ? "" : " (dropins: ",
                              joined,
                              isempty(joined) ? "" : ")");
        else
                log_link_info(link, "Configuring with %s%s%s%s.",
                              network->filename,
                              isempty(joined) ? "" : " (dropins: ",
                              joined,
                              isempty(joined) ? "" : ")");

        /* Dropping configurations based on the old .network file. */
        r = link_drop_requests(link);
        if (r < 0)
                return r;

        /* The bound_to map depends on .network file, hence it needs to be freed. But, do not free the
         * bound_by map. Otherwise, if a link enters unmanaged state below, then its carrier state will
         * not propagated to other interfaces anymore. Moreover, it is not necessary to recreate the
         * map here, as it depends on .network files assigned to other links. */
        link_free_bound_to_list(link);

        _cleanup_(network_unrefp) Network *old_network = TAKE_PTR(link->network);

        /* Then, apply new .network file */
        link->network = network_ref(network);

        if (FLAGS_SET(network->keep_configuration, KEEP_CONFIGURATION_DYNAMIC) ||
            !FLAGS_SET(flags, LINK_RECONFIGURE_CLEANLY)) {
                /* To make 'networkctl reconfigure INTERFACE' work safely for an interface whose new .network
                 * file has KeepConfiguration=dynamic or yes, even if a clean reconfiguration is requested,
                 * drop only unnecessary or possibly being changed dynamic configurations here. */
                r = link_drop_dynamic_config(link, old_network);
                if (r < 0)
                        return r;
        } else {
                /* Otherwise, stop DHCP client and friends unconditionally, and drop all dynamic
                 * configurations like DHCP address and routes. */
                r = link_stop_engines(link, /* may_keep_dynamic = */ false);
                if (r < 0)
                        return r;

                /* Free DHCP client and friends. */
                link_free_engines(link);
        }

        link_update_operstate(link, true);
        link_dirty(link);

        link_set_state(link, LINK_STATE_INITIALIZED);
        link->activated = false;

        r = link_configure(link);
        if (r < 0)
                return r;

        return 1;
}

typedef struct LinkReconfigurationData {
        Manager *manager;
        Link *link;
        LinkReconfigurationFlag flags;
        sd_bus_message *message;
        unsigned *counter;
} LinkReconfigurationData;

static LinkReconfigurationData* link_reconfiguration_data_free(LinkReconfigurationData *data) {
        if (!data)
                return NULL;

        link_unref(data->link);
        sd_bus_message_unref(data->message);

        return mfree(data);
}

DEFINE_TRIVIAL_CLEANUP_FUNC(LinkReconfigurationData*, link_reconfiguration_data_free);

static void link_reconfiguration_data_destroy_callback(LinkReconfigurationData *data) {
        int r;

        assert(data);

        if (data->message) {
                if (data->counter) {
                        assert(*data->counter > 0);
                        (*data->counter)--;
                }

                if (!data->counter || *data->counter <= 0) {
                        /* Update the state files before replying the bus method. Otherwise,
                         * systemd-networkd-wait-online following networkctl reload/reconfigure may read an
                         * outdated state file and wrongly handle an interface is already in the configured
                         * state. */
                        (void) manager_clean_all(data->manager);

                        r = sd_bus_reply_method_return(data->message, NULL);
                        if (r < 0)
                                log_warning_errno(r, "Failed to reply for DBus method, ignoring: %m");
                }
        }

        link_reconfiguration_data_free(data);
}

static int link_reconfigure_handler(sd_netlink *rtnl, sd_netlink_message *m, LinkReconfigurationData *data) {
        Link *link = ASSERT_PTR(ASSERT_PTR(data)->link);
        int r;

        r = link_getlink_handler_internal(rtnl, m, link, "Failed to update link state");
        if (r <= 0)
                return r;

        r = link_reconfigure_impl(link, data->flags);
        if (r < 0) {
                link_enter_failed(link);
                return 0;
        }

        return r;
}

int link_reconfigure_full(Link *link, LinkReconfigurationFlag flags, sd_bus_message *message, unsigned *counter) {
        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL;
        _cleanup_(link_reconfiguration_data_freep) LinkReconfigurationData *data = NULL;
        int r;

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

        /* When the link is in the pending or initialized state, link_reconfigure_impl() will be called later
         * by link_initialized() or link_initialized_and_synced(). To prevent the function from being called
         * multiple times simultaneously, let's refuse to reconfigure the interface here in such cases. */
        if (IN_SET(link->state, LINK_STATE_PENDING, LINK_STATE_INITIALIZED, LINK_STATE_LINGER))
                return 0; /* 0 means no-op. */

        data = new(LinkReconfigurationData, 1);
        if (!data) {
                r = -ENOMEM;
                goto failed;
        }

        *data = (LinkReconfigurationData) {
                .manager = link->manager,
                .link = link_ref(link),
                .flags = flags,
                .message = sd_bus_message_ref(message), /* message may be NULL, but _ref() works fine. */
                .counter = counter,
        };

        r = sd_rtnl_message_new_link(link->manager->rtnl, &req, RTM_GETLINK, link->ifindex);
        if (r < 0)
                goto failed;

        r = netlink_call_async(link->manager->rtnl, NULL, req,
                               link_reconfigure_handler,
                               link_reconfiguration_data_destroy_callback, data);
        if (r < 0)
                goto failed;

        TAKE_PTR(data);
        if (counter)
                (*counter)++;

        if (link->state == LINK_STATE_FAILED)
                link_set_state(link, LINK_STATE_INITIALIZED);

        return 1; /* 1 means the interface will be reconfigured, and bus method will be replied later. */

failed:
        log_link_warning_errno(link, r, "Failed to reconfigure interface: %m");
        link_enter_failed(link);
        return r;
}

static int link_initialized_and_synced(Link *link) {
        int r;

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

        if (link->state == LINK_STATE_PENDING) {
                log_link_debug(link, "Link state is up-to-date");
                link_set_state(link, LINK_STATE_INITIALIZED);

                r = link_new_bound_by_list(link);
                if (r < 0)
                        return r;

                r = link_handle_bound_by_list(link);
                if (r < 0)
                        return r;
        }

        return link_reconfigure_impl(link, /* flags = */ 0);
}

static int link_initialized_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
        int r;

        r = link_getlink_handler_internal(rtnl, m, link, "Failed to wait for the interface to be initialized");
        if (r <= 0)
                return r;

        r = link_initialized_and_synced(link);
        if (r < 0)
                link_enter_failed(link);

        return 0;
}

static int link_initialized(Link *link, sd_device *device) {
        int r;

        assert(link);
        assert(device);

        /* Always replace with the new sd_device object. As the sysname (and possibly other properties
         * or sysattrs) may be outdated. */
        device_unref_and_replace(link->dev, device);

        r = link_managed_by_us(link);
        if (r <= 0)
                return r;

        if (link->dhcp_client) {
                r = sd_dhcp_client_attach_device(link->dhcp_client, link->dev);
                if (r < 0)
                        log_link_warning_errno(link, r, "Failed to attach device to DHCPv4 client, ignoring: %m");
        }

        if (link->dhcp6_client) {
                r = sd_dhcp6_client_attach_device(link->dhcp6_client, link->dev);
                if (r < 0)
                        log_link_warning_errno(link, r, "Failed to attach device to DHCPv6 client, ignoring: %m");
        }

        r = link_set_sr_iov_ifindices(link);
        if (r < 0)
                log_link_warning_errno(link, r, "Failed to manage SR-IOV PF and VF ports, ignoring: %m");

        if (link->state != LINK_STATE_PENDING)
                return link_reconfigure(link, /* flags = */ 0);

        log_link_debug(link, "udev initialized link");

        /* udev has initialized the link, but we don't know if we have yet
         * processed the NEWLINK messages with the latest state. Do a GETLINK,
         * when it returns we know that the pending NEWLINKs have already been
         * processed and that we are up-to-date */

        return link_call_getlink(link, link_initialized_handler);
}

int link_check_initialized(Link *link) {
        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
        int r;

        assert(link);

        if (!udev_available())
                return link_initialized_and_synced(link);

        /* udev should be around */
        r = sd_device_new_from_ifindex(&device, link->ifindex);
        if (r < 0) {
                log_link_debug_errno(link, r, "Could not find device, waiting for device initialization: %m");
                return 0;
        }

        r = device_is_processed(device);
        if (r < 0)
                return log_link_warning_errno(link, r, "Could not determine whether the device is processed by udevd: %m");
        if (r == 0) {
                /* not yet ready */
                log_link_debug(link, "link pending udev initialization...");
                return 0;
        }

        r = device_is_renaming(device);
        if (r < 0)
                return log_link_warning_errno(link, r, "Failed to determine the device is being renamed: %m");
        if (r > 0) {
                log_link_debug(link, "Interface is being renamed, pending initialization.");
                return 0;
        }

        return link_initialized(link, device);
}

int manager_udev_process_link(Manager *m, sd_device *device, sd_device_action_t action) {
        int r, ifindex;
        Link *link;

        assert(m);
        assert(device);

        r = sd_device_get_ifindex(device, &ifindex);
        if (r < 0)
                return log_device_debug_errno(device, r, "Failed to get ifindex: %m");

        r = link_get_by_index(m, ifindex, &link);
        if (r < 0) {
                /* This error is not critical, as the corresponding rtnl message may be received later. */
                log_device_debug_errno(device, r, "Failed to get link from ifindex %i, ignoring: %m", ifindex);
                return 0;
        }

        /* Let's unref the sd-device object assigned to the corresponding Link object, but keep the Link
         * object here. It will be removed only when rtnetlink says so. */
        if (action == SD_DEVICE_REMOVE) {
                link->dev = sd_device_unref(link->dev);
                return 0;
        }

        r = device_is_renaming(device);
        if (r < 0)
                return log_device_debug_errno(device, r, "Failed to determine if the device is renaming or not: %m");
        if (r > 0) {
                log_device_debug(device, "Device is renaming, waiting for the interface to be renamed.");
                /* TODO:
                 * What happens when a device is initialized, then soon renamed after that? When we detect
                 * such, maybe we should cancel or postpone all queued requests for the interface. */
                return 0;
        }

        r = link_initialized(link, device);
        if (r < 0)
                link_enter_failed(link);

        return 0;
}

static int link_carrier_gained(Link *link) {
        LinkReconfigurationFlag flags = 0;
        int r;

        assert(link);

        log_link_info(link, "Gained carrier");

        r = event_source_disable(link->carrier_lost_timer);
        if (r < 0)
                log_link_warning_errno(link, r, "Failed to disable carrier lost timer, ignoring: %m");

        /* Process BindCarrier= setting specified by other interfaces. This is independent of the .network
         * file assigned to this interface, but depends on .network files assigned to other interfaces.
         * Hence, this can and should be called earlier. */
        r = link_handle_bound_by_list(link);
        if (r < 0)
                return r;

        /* If a wireless interface was connected to an access point, and the SSID is changed (that is,
         * both previous_ssid and ssid are non-NULL), then the connected wireless network could be
         * changed. So, always reconfigure the link. Which means e.g. the DHCP client will be
         * restarted, and the correct network information will be gained.
         *
         * However, do not reconfigure the wireless interface forcibly if it was not connected to any
         * access points previously (previous_ssid is NULL in this case). As, a .network file may be
         * already assigned to the interface (in that case, the .network file does not have the SSID=
         * setting in the [Match] section), and the interface is already being configured. Of course,
         * there may exist another .network file with higher priority and a matching SSID= setting. But
         * in that case, link_reconfigure_impl() can handle that without any flags.
         *
         * For non-wireless interfaces, we have no way to detect the connected network change. So,
         * we do not set any flags here. Note, both ssid and previous_ssid are NULL in that case. */
        if (link->previous_ssid && !streq_ptr(link->previous_ssid, link->ssid))
                flags |= LINK_RECONFIGURE_UNCONDITIONALLY | LINK_RECONFIGURE_CLEANLY;
        link->previous_ssid = mfree(link->previous_ssid);

        /* AP and P2P-GO interfaces may have a new SSID - update the link properties in case a new .network
         * profile wants to match on it with SSID= in its [Match] section.
         */
        if (IN_SET(link->wlan_iftype, NL80211_IFTYPE_AP, NL80211_IFTYPE_P2P_GO)) {
                r = link_get_wlan_interface(link);
                if (r < 0)
                        return r;
        }

        /* At this stage, both wlan and link information should be up-to-date. Hence, it is not necessary to
         * call RTM_GETLINK, NL80211_CMD_GET_INTERFACE, or NL80211_CMD_GET_STATION commands, and simply call
         * link_reconfigure_impl(). Note, link_reconfigure_impl() returns 1 when the link is reconfigured. */
        r = link_reconfigure_impl(link, flags);
        if (r != 0)
                return r;

        if (link->iftype == ARPHRD_CAN)
                /* let's shortcut things for CAN which doesn't need most of what's done below. */
                return 0;

        if (IN_SET(link->state, LINK_STATE_CONFIGURING, LINK_STATE_CONFIGURED)) {
                r = link_acquire_dynamic_conf(link);
                if (r < 0)
                        return r;

                r = link_request_static_configs(link);
                if (r < 0)
                        return r;
        }

        return 0;
}

static int link_carrier_lost_impl(Link *link) {
        int ret = 0;

        assert(link);

        link->previous_ssid = mfree(link->previous_ssid);

        ret = link_handle_bound_by_list(link);

        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
                return ret;

        if (!link->network)
                return ret;

        RET_GATHER(ret, link_stop_engines(link, /* may_keep_dynamic = */ false));
        RET_GATHER(ret, link_drop_static_config(link));

        return ret;
}

static int link_carrier_lost_handler(sd_event_source *s, uint64_t usec, void *userdata) {
        Link *link = ASSERT_PTR(userdata);
        int r;

        r = link_carrier_lost_impl(link);
        if (r < 0) {
                log_link_warning_errno(link, r, "Failed to process carrier lost event: %m");
                link_enter_failed(link);
        }

        return 0;
}

static int link_carrier_lost(Link *link) {
        uint16_t dhcp_mtu;
        usec_t usec;

        assert(link);

        log_link_info(link, "Lost carrier");

        if (link->iftype == ARPHRD_CAN)
                /* let's shortcut things for CAN which doesn't need most of what's done below. */
                usec = 0;

        else if (!link->network)
                usec = 0;

        else if (link->network->ignore_carrier_loss_set)
                /* If IgnoreCarrierLoss= is explicitly specified, then use the specified value. */
                usec = link->network->ignore_carrier_loss_usec;

        else if (link->network->bond && link->wlan_iftype > 0)
                /* Enslaving wlan interface to a bond disconnects from the connected AP, and causes its
                 * carrier to be lost. See #19832. */
                usec = 3 * USEC_PER_SEC;

        else if (link->network->dhcp_use_mtu &&
                 link->dhcp_lease &&
                 sd_dhcp_lease_get_mtu(link->dhcp_lease, &dhcp_mtu) >= 0 &&
                 dhcp_mtu != link->original_mtu)
                /* Some drivers reset interfaces when changing MTU. Resetting interfaces by the static
                 * MTU should not cause any issues, as MTU is changed only once. However, setting MTU
                 * through DHCP lease causes an infinite loop of resetting the interface. See #18738. */
                usec = 5 * USEC_PER_SEC;

        else
                /* Otherwise, use the implied default value. */
                usec = link->network->ignore_carrier_loss_usec;

        if (usec == USEC_INFINITY)
                return 0;

        if (usec == 0)
                return link_carrier_lost_impl(link);

        return event_reset_time_relative(link->manager->event,
                                         &link->carrier_lost_timer,
                                         CLOCK_BOOTTIME,
                                         usec,
                                         0,
                                         link_carrier_lost_handler,
                                         link,
                                         0,
                                         "link-carrier-loss",
                                         true);
}

static int link_admin_state_up(Link *link) {
        assert(link);

        /* This is called every time an interface admin state changes to up;
         * specifically, when IFF_UP flag changes from unset to set. */

        log_link_info(link, "Link UP");

        if (!link->network)
                return 0;

        if (link->activated && link->network->activation_policy == ACTIVATION_POLICY_ALWAYS_DOWN) {
                log_link_info(link, "Activation policy is \"always-down\", forcing link down.");
                return link_request_to_bring_up_or_down(link, /* up = */ false);
        }

        /* We set the ipv6 mtu after the device mtu, but the kernel resets
         * ipv6 mtu on NETDEV_UP, so we need to reset it. */
        (void) link_set_ipv6_mtu(link, LOG_INFO);

        return 0;
}

static int link_admin_state_down(Link *link) {
        assert(link);

        log_link_info(link, "Link DOWN");

        link_forget_nexthops(link);
        link_forget_routes(link);

        if (!link->network)
                return 0;

        if (link->activated && link->network->activation_policy == ACTIVATION_POLICY_ALWAYS_UP) {
                log_link_info(link, "Activation policy is \"always-up\", forcing link up.");
                return link_request_to_bring_up_or_down(link, /* up = */ true);
        }

        return 0;
}

static bool link_is_enslaved(Link *link) {
        if (link->flags & IFF_SLAVE)
                return true;

        if (link->master_ifindex > 0)
                return true;

        return false;
}

void link_update_operstate(Link *link, bool also_update_master) {
        LinkOperationalState operstate;
        LinkCarrierState carrier_state;
        LinkAddressState ipv4_address_state, ipv6_address_state, address_state;
        LinkOnlineState online_state;
        _cleanup_strv_free_ char **p = NULL;
        bool changed = false;

        assert(link);

        if (link->kernel_operstate == IF_OPER_DORMANT)
                carrier_state = LINK_CARRIER_STATE_DORMANT;
        else if (link_has_carrier(link)) {
                if (link_is_enslaved(link))
                        carrier_state = LINK_CARRIER_STATE_ENSLAVED;
                else
                        carrier_state = LINK_CARRIER_STATE_CARRIER;
        } else if (link->flags & IFF_UP)
                carrier_state = LINK_CARRIER_STATE_NO_CARRIER;
        else
                carrier_state = LINK_CARRIER_STATE_OFF;

        if (carrier_state >= LINK_CARRIER_STATE_CARRIER) {
                Link *slave;

                SET_FOREACH(slave, link->slaves) {
                        link_update_operstate(slave, false);

                        if (slave->carrier_state < LINK_CARRIER_STATE_CARRIER)
                                carrier_state = LINK_CARRIER_STATE_DEGRADED_CARRIER;
                }
        }

        link_get_address_states(link, &ipv4_address_state, &ipv6_address_state, &address_state);

        /* Mapping of address and carrier state vs operational state
         *                                                     carrier state
         *                          | off | no-carrier | dormant | degraded-carrier | carrier  | enslaved
         *                 ------------------------------------------------------------------------------
         *                 off      | off | no-carrier | dormant | degraded-carrier | carrier  | enslaved
         * address_state   degraded | off | no-carrier | dormant | degraded         | degraded | enslaved
         *                 routable | off | no-carrier | dormant | routable         | routable | routable
         */

        if (carrier_state == LINK_CARRIER_STATE_DEGRADED_CARRIER && address_state == LINK_ADDRESS_STATE_ROUTABLE)
                operstate = LINK_OPERSTATE_ROUTABLE;
        else if (carrier_state == LINK_CARRIER_STATE_DEGRADED_CARRIER && address_state == LINK_ADDRESS_STATE_DEGRADED)
                operstate = LINK_OPERSTATE_DEGRADED;
        else if (carrier_state < LINK_CARRIER_STATE_CARRIER || address_state == LINK_ADDRESS_STATE_OFF)
                operstate = (LinkOperationalState) carrier_state;
        else if (address_state == LINK_ADDRESS_STATE_ROUTABLE)
                operstate = LINK_OPERSTATE_ROUTABLE;
        else if (carrier_state == LINK_CARRIER_STATE_CARRIER)
                operstate = LINK_OPERSTATE_DEGRADED;
        else
                operstate = LINK_OPERSTATE_ENSLAVED;

        LinkOperationalStateRange req;
        link_required_operstate_for_online(link, &req);

        /* Only determine online state for managed links with RequiredForOnline=yes */
        if (!link->network || !link->network->required_for_online)
                online_state = _LINK_ONLINE_STATE_INVALID;

        else if (!operational_state_is_in_range(operstate, &req))
                online_state = LINK_ONLINE_STATE_OFFLINE;

        else {
                AddressFamily required_family = link_required_family_for_online(link);
                bool needs_ipv4 = required_family & ADDRESS_FAMILY_IPV4;
                bool needs_ipv6 = required_family & ADDRESS_FAMILY_IPV6;

                /* The operational state is within the range required for online.
                 * If a particular address family is also required, we might revert
                 * to offline in the blocks below. */
                online_state = LINK_ONLINE_STATE_ONLINE;

                if (req.min >= LINK_OPERSTATE_DEGRADED) {
                        if (needs_ipv4 && ipv4_address_state < LINK_ADDRESS_STATE_DEGRADED)
                                online_state = LINK_ONLINE_STATE_OFFLINE;
                        if (needs_ipv6 && ipv6_address_state < LINK_ADDRESS_STATE_DEGRADED)
                                online_state = LINK_ONLINE_STATE_OFFLINE;
                }

                if (req.min >= LINK_OPERSTATE_ROUTABLE) {
                        if (needs_ipv4 && ipv4_address_state < LINK_ADDRESS_STATE_ROUTABLE)
                                online_state = LINK_ONLINE_STATE_OFFLINE;
                        if (needs_ipv6 && ipv6_address_state < LINK_ADDRESS_STATE_ROUTABLE)
                                online_state = LINK_ONLINE_STATE_OFFLINE;
                }
        }

        if (link->carrier_state != carrier_state) {
                link->carrier_state = carrier_state;
                changed = true;
                if (strv_extend(&p, "CarrierState") < 0)
                        log_oom();
        }

        if (link->address_state != address_state) {
                link->address_state = address_state;
                changed = true;
                if (strv_extend(&p, "AddressState") < 0)
                        log_oom();
        }

        if (link->ipv4_address_state != ipv4_address_state) {
                link->ipv4_address_state = ipv4_address_state;
                changed = true;
                if (strv_extend(&p, "IPv4AddressState") < 0)
                        log_oom();
        }

        if (link->ipv6_address_state != ipv6_address_state) {
                link->ipv6_address_state = ipv6_address_state;
                changed = true;
                if (strv_extend(&p, "IPv6AddressState") < 0)
                        log_oom();
        }

        if (link->operstate != operstate) {
                link->operstate = operstate;
                changed = true;
                if (strv_extend(&p, "OperationalState") < 0)
                        log_oom();
        }

        if (link->online_state != online_state) {
                link->online_state = online_state;
                changed = true;
                if (strv_extend(&p, "OnlineState") < 0)
                        log_oom();
        }

        if (p)
                link_send_changed_strv(link, p);
        if (changed)
                link_dirty(link);

        if (also_update_master) {
                Link *master;

                if (link_get_master(link, &master) >= 0)
                        link_update_operstate(master, true);
        }
}

bool link_has_carrier(Link *link) {
        assert(link);
        return netif_has_carrier(link->kernel_operstate, link->flags);
}

bool link_multicast_enabled(Link *link) {
        assert(link);

        /* If Multicast= is specified, use the value. */
        if (link->network && link->network->multicast >= 0)
                return link->network->multicast;

        /* Otherwise, return the current state. */
        return FLAGS_SET(link->flags, IFF_MULTICAST);
}

#define FLAG_STRING(string, flag, old, new)                      \
        (((old ^ new) & flag)                                    \
         ? ((old & flag) ? (" -" string) : (" +" string))        \
         : "")

static int link_update_flags(Link *link, sd_netlink_message *message) {
        bool link_was_admin_up, had_carrier;
        uint8_t operstate;
        unsigned flags;
        int r;

        assert(link);
        assert(message);

        r = sd_rtnl_message_link_get_flags(message, &flags);
        if (r < 0)
                return log_link_debug_errno(link, r, "rtnl: failed to read link flags: %m");

        r = sd_netlink_message_read_u8(message, IFLA_OPERSTATE, &operstate);
        if (r == -ENODATA)
                /* If we got a message without operstate, assume the state was unchanged. */
                operstate = link->kernel_operstate;
        else if (r < 0)
                return log_link_debug_errno(link, r, "rtnl: failed to read operational state: %m");

        if (link->flags == flags && link->kernel_operstate == operstate)
                return 0;

        if (link->flags != flags) {
                unsigned unknown_flags, unknown_flags_added, unknown_flags_removed;

                log_link_debug(link, "Flags change:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
                               FLAG_STRING("LOOPBACK", IFF_LOOPBACK, link->flags, flags),
                               FLAG_STRING("MASTER", IFF_MASTER, link->flags, flags),
                               FLAG_STRING("SLAVE", IFF_SLAVE, link->flags, flags),
                               FLAG_STRING("UP", IFF_UP, link->flags, flags),
                               FLAG_STRING("DORMANT", IFF_DORMANT, link->flags, flags),
                               FLAG_STRING("LOWER_UP", IFF_LOWER_UP, link->flags, flags),
                               FLAG_STRING("RUNNING", IFF_RUNNING, link->flags, flags),
                               FLAG_STRING("MULTICAST", IFF_MULTICAST, link->flags, flags),
                               FLAG_STRING("BROADCAST", IFF_BROADCAST, link->flags, flags),
                               FLAG_STRING("POINTOPOINT", IFF_POINTOPOINT, link->flags, flags),
                               FLAG_STRING("PROMISC", IFF_PROMISC, link->flags, flags),
                               FLAG_STRING("ALLMULTI", IFF_ALLMULTI, link->flags, flags),
                               FLAG_STRING("PORTSEL", IFF_PORTSEL, link->flags, flags),
                               FLAG_STRING("AUTOMEDIA", IFF_AUTOMEDIA, link->flags, flags),
                               FLAG_STRING("DYNAMIC", IFF_DYNAMIC, link->flags, flags),
                               FLAG_STRING("NOARP", IFF_NOARP, link->flags, flags),
                               FLAG_STRING("NOTRAILERS", IFF_NOTRAILERS, link->flags, flags),
                               FLAG_STRING("DEBUG", IFF_DEBUG, link->flags, flags),
                               FLAG_STRING("ECHO", IFF_ECHO, link->flags, flags));

                unknown_flags = ~(IFF_LOOPBACK | IFF_MASTER | IFF_SLAVE | IFF_UP |
                                  IFF_DORMANT | IFF_LOWER_UP | IFF_RUNNING |
                                  IFF_MULTICAST | IFF_BROADCAST | IFF_POINTOPOINT |
                                  IFF_PROMISC | IFF_ALLMULTI | IFF_PORTSEL |
                                  IFF_AUTOMEDIA | IFF_DYNAMIC | IFF_NOARP |
                                  IFF_NOTRAILERS | IFF_DEBUG | IFF_ECHO);
                unknown_flags_added = ((link->flags ^ flags) & flags & unknown_flags);
                unknown_flags_removed = ((link->flags ^ flags) & link->flags & unknown_flags);

                if (unknown_flags_added)
                        log_link_debug(link, "Unknown link flags gained, ignoring: %#.5x", unknown_flags_added);

                if (unknown_flags_removed)
                        log_link_debug(link, "Unknown link flags lost, ignoring: %#.5x", unknown_flags_removed);
        }

        link_was_admin_up = link->flags & IFF_UP;
        had_carrier = link_has_carrier(link);

        link->flags = flags;
        link->kernel_operstate = operstate;

        link_update_operstate(link, true);

        r = 0;

        if (!link_was_admin_up && (link->flags & IFF_UP))
                r = link_admin_state_up(link);
        else if (link_was_admin_up && !(link->flags & IFF_UP))
                r = link_admin_state_down(link);
        if (r < 0)
                return r;

        if (!had_carrier && link_has_carrier(link))
                r = link_carrier_gained(link);
        else if (had_carrier && !link_has_carrier(link))
                r = link_carrier_lost(link);
        if (r < 0)
                return r;

        return 0;
}

static int link_update_master(Link *link, sd_netlink_message *message) {
        int master_ifindex, r;

        assert(link);
        assert(message);

        r = sd_netlink_message_read_u32(message, IFLA_MASTER, (uint32_t*) &master_ifindex);
        if (r == -ENODATA)
                master_ifindex = 0; /* no master interface */
        else if (r < 0)
                return log_link_debug_errno(link, r, "rtnl: failed to read master ifindex: %m");

        if (master_ifindex == link->ifindex)
                master_ifindex = 0;

        if (master_ifindex != link->master_ifindex) {
                if (link->master_ifindex == 0)
                        log_link_debug(link, "Attached to master interface: %i", master_ifindex);
                else if (master_ifindex == 0)
                        log_link_debug(link, "Detached from master interface: %i", link->master_ifindex);
                else
                        log_link_debug(link, "Master interface changed: %i %s %i", link->master_ifindex,
                                       glyph(GLYPH_ARROW_RIGHT), master_ifindex);

                link_drop_from_master(link);
                link->master_ifindex = master_ifindex;

                /* Updating master ifindex may cause operational state change, e.g. carrier <-> enslaved */
                link_dirty(link);
        }

        r = link_append_to_master(link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Failed to append link to master: %m");

        return 0;
}

static int link_update_driver(Link *link, sd_netlink_message *message) {
        int r;

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

        /* Driver is already read. Assuming the driver is never changed. */
        if (link->ethtool_driver_read)
                return 0;

        /* When udevd is running, read the driver after the interface is initialized by udevd.
         * Otherwise, ethtool may not work correctly. See issue #22538.
         * When udevd is not running, read the value when the interface is detected. */
        if (udev_available() && !link->dev)
                return 0;

        link->ethtool_driver_read = true;

        r = ethtool_get_driver(&link->manager->ethtool_fd, link->ifname, &link->driver);
        if (r < 0) {
                log_link_debug_errno(link, r, "Failed to get driver, continuing without: %m");
                return 0;
        }

        log_link_debug(link, "Found driver: %s", strna(link->driver));

        if (streq_ptr(link->driver, "dsa")) {
                uint32_t dsa_master_ifindex = 0;

                r = sd_netlink_message_read_u32(message, IFLA_LINK, &dsa_master_ifindex);
                if (r < 0 && r != -ENODATA)
                        return log_link_debug_errno(link, r, "rtnl: failed to read ifindex of the DSA master interface: %m");

                if (dsa_master_ifindex > INT_MAX) {
                        log_link_debug(link, "rtnl: received too large DSA master ifindex (%"PRIu32" > INT_MAX), ignoring.",
                                       dsa_master_ifindex);
                        dsa_master_ifindex = 0;
                }

                link->dsa_master_ifindex = (int) dsa_master_ifindex;
        }

        return 1; /* needs reconfigure */
}

static int link_update_permanent_hardware_address_from_ethtool(Link *link, sd_netlink_message *message) {
        int r;

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

        if (link->ethtool_permanent_hw_addr_read)
                return 0;

        /* When udevd is running, read the permanent hardware address after the interface is
         * initialized by udevd. Otherwise, ethtool may not work correctly. See issue #22538.
         * When udevd is not running, read the value when the interface is detected. */
        if (udev_available() && !link->dev)
                return 0;

        /* If the interface does not have a hardware address, then it will not have a permanent address either. */
        r = netlink_message_read_hw_addr(message, IFLA_ADDRESS, NULL);
        if (r == -ENODATA)
                return 0;
        if (r < 0)
                return log_link_debug_errno(link, r, "Failed to read IFLA_ADDRESS attribute: %m");

        link->ethtool_permanent_hw_addr_read = true;

        r = ethtool_get_permanent_hw_addr(&link->manager->ethtool_fd, link->ifname, &link->permanent_hw_addr);
        if (r < 0)
                log_link_debug_errno(link, r, "Permanent hardware address not found, continuing without: %m");

        return 0;
}

static int link_update_permanent_hardware_address(Link *link, sd_netlink_message *message) {
        int r;

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

        if (link->permanent_hw_addr.length > 0)
                return 0;

        r = netlink_message_read_hw_addr(message, IFLA_PERM_ADDRESS, &link->permanent_hw_addr);
        if (r < 0) {
                if (r != -ENODATA)
                        return log_link_debug_errno(link, r, "Failed to read IFLA_PERM_ADDRESS attribute: %m");

                /* Fallback to ethtool for kernels older than v5.6 (f74877a5457d34d604dba6dbbb13c4c05bac8b93). */
                r = link_update_permanent_hardware_address_from_ethtool(link, message);
                if (r < 0)
                        return r;
        }

        if (link->permanent_hw_addr.length > 0)
                log_link_debug(link, "Saved permanent hardware address: %s", HW_ADDR_TO_STR(&link->permanent_hw_addr));

        return 1; /* needs reconfigure */
}

static int link_update_hardware_address(Link *link, sd_netlink_message *message) {
        struct hw_addr_data addr;
        int r;

        assert(link);
        assert(message);

        r = netlink_message_read_hw_addr(message, IFLA_BROADCAST, &link->bcast_addr);
        if (r < 0 && r != -ENODATA)
                return log_link_debug_errno(link, r, "rtnl: failed to read broadcast address: %m");

        r = netlink_message_read_hw_addr(message, IFLA_ADDRESS, &addr);
        if (r == -ENODATA)
                return 0;
        if (r < 0)
                return log_link_debug_errno(link, r, "rtnl: failed to read hardware address: %m");

        if (hw_addr_equal(&link->hw_addr, &addr))
                return 0;

        if (link->hw_addr.length == 0)
                log_link_debug(link, "Saved hardware address: %s", HW_ADDR_TO_STR(&addr));
        else {
                log_link_debug(link, "Hardware address is changed: %s %s %s",
                               HW_ADDR_TO_STR(&link->hw_addr),
                               glyph(GLYPH_ARROW_RIGHT),
                               HW_ADDR_TO_STR(&addr));

                hashmap_remove_value(link->manager->links_by_hw_addr, &link->hw_addr, link);
        }

        link->hw_addr = addr;

        if (!hw_addr_is_null(&link->hw_addr)) {
                r = hashmap_ensure_put(&link->manager->links_by_hw_addr, &hw_addr_hash_ops, &link->hw_addr, link);
                if (r == -EEXIST && streq_ptr(link->kind, "bond"))
                        /* bonding master and its slaves have the same hardware address. */
                        r = hashmap_replace(link->manager->links_by_hw_addr, &link->hw_addr, link);
                if (r < 0)
                        log_link_debug_errno(link, r, "Failed to manage link by its new hardware address, ignoring: %m");
        }

        r = ipv4acd_update_mac(link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Could not update MAC address in IPv4 ACD client: %m");

        r = ipv4ll_update_mac(link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Could not update MAC address in IPv4LL client: %m");

        r = dhcp4_update_mac(link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Could not update MAC address in DHCP client: %m");

        r = dhcp6_update_mac(link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Could not update MAC address in DHCPv6 client: %m");

        r = radv_update_mac(link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Could not update MAC address for Router Advertisement: %m");

        if (link->ndisc && link->hw_addr.length == ETH_ALEN) {
                r = sd_ndisc_set_mac(link->ndisc, &link->hw_addr.ether);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Could not update MAC for NDisc: %m");
        }

        if (link->lldp_rx) {
                r = sd_lldp_rx_set_filter_address(link->lldp_rx, &link->hw_addr.ether);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Could not update MAC address for LLDP Rx: %m");
        }

        if (link->lldp_tx) {
                r = sd_lldp_tx_set_hwaddr(link->lldp_tx, &link->hw_addr.ether);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Could not update MAC address for LLDP Tx: %m");
        }

        return 1; /* needs reconfigure */
}

static int link_update_mtu(Link *link, sd_netlink_message *message) {
        uint32_t mtu, min_mtu = 0, max_mtu = UINT32_MAX;
        int r;

        assert(link);
        assert(message);

        r = sd_netlink_message_read_u32(message, IFLA_MTU, &mtu);
        if (r == -ENODATA)
                return 0;
        if (r < 0)
                return log_link_debug_errno(link, r, "rtnl: failed to read MTU in RTM_NEWLINK message: %m");
        if (mtu == 0)
                return 0;

        r = sd_netlink_message_read_u32(message, IFLA_MIN_MTU, &min_mtu);
        if (r < 0 && r != -ENODATA)
                return log_link_debug_errno(link, r, "rtnl: failed to read minimum MTU in RTM_NEWLINK message: %m");

        r = sd_netlink_message_read_u32(message, IFLA_MAX_MTU, &max_mtu);
        if (r < 0 && r != -ENODATA)
                return log_link_debug_errno(link, r, "rtnl: failed to read maximum MTU in RTM_NEWLINK message: %m");

        if (max_mtu == 0)
                max_mtu = UINT32_MAX;

        link->min_mtu = min_mtu;
        link->max_mtu = max_mtu;

        if (link->original_mtu == 0) {
                link->original_mtu = mtu;
                log_link_debug(link, "Saved original MTU %" PRIu32" (min: %"PRIu32", max: %"PRIu32")",
                               link->original_mtu, link->min_mtu, link->max_mtu);
        }

        if (link->mtu == mtu)
                return 0;

        if (link->mtu != 0)
                log_link_debug(link, "MTU is changed: %"PRIu32" %s %"PRIu32" (min: %"PRIu32", max: %"PRIu32")",
                               link->mtu, glyph(GLYPH_ARROW_RIGHT), mtu,
                               link->min_mtu, link->max_mtu);

        link->mtu = mtu;

        if (IN_SET(link->state, LINK_STATE_CONFIGURING, LINK_STATE_CONFIGURED))
                /* The kernel resets IPv6 MTU after changing device MTU. So, we need to re-set IPv6 MTU again. */
                (void) link_set_ipv6_mtu_async(link);

        if (link->dhcp_client) {
                r = sd_dhcp_client_set_mtu(link->dhcp_client, link->mtu);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Could not update MTU in DHCP client: %m");
        }

        if (link->radv) {
                r = sd_radv_set_mtu(link->radv, link->mtu);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Could not set MTU for Router Advertisement: %m");
        }

        return 0;
}

static int link_update_alternative_names(Link *link, sd_netlink_message *message) {
        _cleanup_strv_free_ char **altnames = NULL;
        int r;

        assert(link);
        assert(message);

        r = sd_netlink_message_read_strv(message, IFLA_PROP_LIST, IFLA_ALT_IFNAME, &altnames);
        if (r == -ENODATA)
                /* The message does not have IFLA_PROP_LIST container attribute. It does not mean the
                 * interface has no alternative name. */
                return 0;
        if (r < 0)
                return log_link_debug_errno(link, r, "rtnl: failed to read alternative names: %m");

        if (strv_equal(altnames, link->alternative_names))
                return 0;

        STRV_FOREACH(n, link->alternative_names)
                hashmap_remove(link->manager->links_by_name, *n);

        strv_free_and_replace(link->alternative_names, altnames);

        STRV_FOREACH(n, link->alternative_names) {
                r = hashmap_ensure_put(&link->manager->links_by_name, &string_hash_ops, *n, link);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to manage link by its new alternative names: %m");
        }

        return 1; /* needs reconfigure */
}

static int link_update_name(Link *link, sd_netlink_message *message) {
        char ifname_from_index[IF_NAMESIZE];
        const char *ifname;
        int r;

        assert(link);
        assert(message);

        r = sd_netlink_message_read_string(message, IFLA_IFNAME, &ifname);
        if (r == -ENODATA)
                /* Hmm?? But ok. */
                return 0;
        if (r < 0)
                return log_link_debug_errno(link, r, "Failed to read interface name in RTM_NEWLINK message: %m");

        if (streq(ifname, link->ifname))
                return 0;

        r = format_ifname(link->ifindex, ifname_from_index);
        if (r < 0)
                return log_link_debug_errno(link, r, "Could not get interface name for index %i.", link->ifindex);

        if (!streq(ifname, ifname_from_index)) {
                log_link_debug(link, "New interface name '%s' received from the kernel does not correspond "
                               "with the name currently configured on the actual interface '%s'. Ignoring.",
                               ifname, ifname_from_index);
                return 0;
        }

        log_link_info(link, "Interface name change detected, renamed to %s.", ifname);

        hashmap_remove(link->manager->links_by_name, link->ifname);

        r = free_and_strdup(&link->ifname, ifname);
        if (r < 0)
                return log_oom_debug();

        r = hashmap_ensure_put(&link->manager->links_by_name, &string_hash_ops, link->ifname, link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Failed to manage link by its new name: %m");

        if (link->dhcp_client) {
                r = sd_dhcp_client_set_ifname(link->dhcp_client, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in DHCP client: %m");
        }

        if (link->dhcp6_client) {
                r = sd_dhcp6_client_set_ifname(link->dhcp6_client, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in DHCPv6 client: %m");
        }

        if (link->ndisc) {
                r = sd_ndisc_set_ifname(link->ndisc, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in NDisc: %m");
        }

        if (link->dhcp_server) {
                r = sd_dhcp_server_set_ifname(link->dhcp_server, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in DHCP server: %m");
        }

        if (link->radv) {
                r = sd_radv_set_ifname(link->radv, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in Router Advertisement: %m");
        }

        if (link->lldp_rx) {
                r = sd_lldp_rx_set_ifname(link->lldp_rx, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in LLDP Rx: %m");
        }

        if (link->lldp_tx) {
                r = sd_lldp_tx_set_ifname(link->lldp_tx, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in LLDP Tx: %m");
        }

        if (link->ipv4ll) {
                r = sd_ipv4ll_set_ifname(link->ipv4ll, link->ifname);
                if (r < 0)
                        return log_link_debug_errno(link, r, "Failed to update interface name in IPv4LL client: %m");
        }

        r = ipv4acd_set_ifname(link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Failed to update interface name in IPv4ACD client: %m");

        return 1; /* needs reconfigure */
}

static int link_update(Link *link, sd_netlink_message *message) {
        bool needs_reconfigure = false;
        int r;

        assert(link);
        assert(message);

        r = link_update_name(link, message);
        if (r < 0)
                return r;
        needs_reconfigure = needs_reconfigure || r > 0;

        r = link_update_alternative_names(link, message);
        if (r < 0)
                return r;
        needs_reconfigure = needs_reconfigure || r > 0;

        r = link_update_mtu(link, message);
        if (r < 0)
                return r;

        r = link_update_driver(link, message);
        if (r < 0)
                return r;
        needs_reconfigure = needs_reconfigure || r > 0;

        r = link_update_permanent_hardware_address(link, message);
        if (r < 0)
                return r;
        needs_reconfigure = needs_reconfigure || r > 0;

        r = link_update_hardware_address(link, message);
        if (r < 0)
                return r;
        needs_reconfigure = needs_reconfigure || r > 0;

        r = link_update_master(link, message);
        if (r < 0)
                return r;

        r = link_update_ipv6ll_addrgen_mode(link, message);
        if (r < 0)
                return r;

        r = link_update_flags(link, message);
        if (r < 0)
                return r;

        r = link_update_bridge_vlan(link, message);
        if (r < 0)
                return r;

        return needs_reconfigure;
}

static Link *link_drop_or_unref(Link *link) {
        if (!link)
                return NULL;
        if (!link->manager)
                return link_unref(link);
        return link_drop(link);
}

DEFINE_TRIVIAL_CLEANUP_FUNC(Link*, link_drop_or_unref);

static int link_new(Manager *manager, sd_netlink_message *message, Link **ret) {
        _cleanup_free_ char *ifname = NULL, *kind = NULL, *state_file = NULL, *lease_file = NULL;
        _cleanup_(link_drop_or_unrefp) Link *link = NULL;
        unsigned short iftype;
        int r, ifindex;

        assert(manager);
        assert(message);
        assert(ret);

        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
        if (r < 0)
                return log_debug_errno(r, "rtnl: failed to read ifindex from link message: %m");
        else if (ifindex <= 0)
                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "rtnl: received link message without valid ifindex.");

        r = sd_rtnl_message_link_get_type(message, &iftype);
        if (r < 0)
                return log_debug_errno(r, "rtnl: failed to read interface type from link message: %m");

        r = sd_netlink_message_read_string_strdup(message, IFLA_IFNAME, &ifname);
        if (r < 0)
                return log_debug_errno(r, "rtnl: failed to read interface name from link message: %m");

        /* check for link kind */
        r = sd_netlink_message_enter_container(message, IFLA_LINKINFO);
        if (r >= 0) {
                r = sd_netlink_message_read_string_strdup(message, IFLA_INFO_KIND, &kind);
                if (r < 0 && r != -ENODATA)
                        return log_debug_errno(r, "rtnl: failed to read interface kind from link message: %m");
                r = sd_netlink_message_exit_container(message);
                if (r < 0)
                        return log_debug_errno(r, "rtnl: failed to exit IFLA_LINKINFO container: %m");
        }

        if (!manager->test_mode) {
                /* Do not update state files when running in test mode. */
                if (asprintf(&state_file, "/run/systemd/netif/links/%d", ifindex) < 0)
                        return log_oom_debug();

                if (asprintf(&lease_file, "/run/systemd/netif/leases/%d", ifindex) < 0)
                        return log_oom_debug();
        }

        link = new(Link, 1);
        if (!link)
                return -ENOMEM;

        *link = (Link) {
                .n_ref = 1,
                .state = LINK_STATE_PENDING,
                .online_state = _LINK_ONLINE_STATE_INVALID,
                .automatic_reconfigure_ratelimit = (const RateLimit) { .interval = 10 * USEC_PER_SEC, .burst = 5 },
                .ifindex = ifindex,
                .iftype = iftype,
                .ifname = TAKE_PTR(ifname),
                .kind = TAKE_PTR(kind),

                .bridge_vlan_pvid = UINT16_MAX,

                .ipv6ll_address_gen_mode = _IPV6_LINK_LOCAL_ADDRESS_GEN_MODE_INVALID,

                .state_file = TAKE_PTR(state_file),
                .lease_file = TAKE_PTR(lease_file),

                .n_dns = UINT_MAX,
                .dns_default_route = -1,
                .llmnr = _RESOLVE_SUPPORT_INVALID,
                .mdns = _RESOLVE_SUPPORT_INVALID,
                .dnssec_mode = _DNSSEC_MODE_INVALID,
                .dns_over_tls_mode = _DNS_OVER_TLS_MODE_INVALID,
        };

        r = hashmap_ensure_put(&manager->links_by_index, &link_hash_ops, INT_TO_PTR(link->ifindex), link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Failed to store link into manager: %m");

        link->manager = manager;

        r = hashmap_ensure_put(&manager->links_by_name, &string_hash_ops, link->ifname, link);
        if (r < 0)
                return log_link_debug_errno(link, r, "Failed to manage link by its interface name: %m");

        log_link_debug(link, "Saved new link: ifindex=%i, iftype=%s(%u), kind=%s",
                       link->ifindex, strna(arphrd_to_name(link->iftype)), link->iftype, strna(link->kind));

        /* If contained in this set, the link is wireless and the corresponding NL80211_CMD_NEW_INTERFACE
         * message arrived too early. Request the wireless link information again.
         */
        if (set_remove(manager->new_wlan_ifindices, INT_TO_PTR(link->ifindex))) {
                r = link_get_wlan_interface(link);
                if (r < 0)
                        log_link_warning_errno(link, r, "Failed to get wireless interface, ignoring: %m");
        }

        *ret = TAKE_PTR(link);
        return 0;
}

int manager_rtnl_process_link(sd_netlink *rtnl, sd_netlink_message *message, Manager *manager) {
        Link *link = NULL;
        NetDev *netdev = NULL;
        uint16_t type;
        const char *name;
        int r, ifindex;

        assert(rtnl);
        assert(message);
        assert(manager);

        if (sd_netlink_message_is_error(message)) {
                r = sd_netlink_message_get_errno(message);
                if (r < 0)
                        log_message_warning_errno(message, r, "rtnl: Could not receive link message, ignoring");

                return 0;
        }

        r = sd_netlink_message_get_type(message, &type);
        if (r < 0) {
                log_warning_errno(r, "rtnl: Could not get message type, ignoring: %m");
                return 0;
        } else if (!IN_SET(type, RTM_NEWLINK, RTM_DELLINK)) {
                log_warning("rtnl: Received unexpected message type %u when processing link, ignoring.", type);
                return 0;
        }

        r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
        if (r < 0) {
                log_warning_errno(r, "rtnl: Could not get ifindex from link message, ignoring: %m");
                return 0;
        } else if (ifindex <= 0) {
                log_warning("rtnl: received link message with invalid ifindex %d, ignoring.", ifindex);
                return 0;
        }

        r = sd_netlink_message_read_string(message, IFLA_IFNAME, &name);
        if (r < 0) {
                log_warning_errno(r, "rtnl: Received link message without ifname, ignoring: %m");
                return 0;
        }

        (void) link_get_by_index(manager, ifindex, &link);
        (void) netdev_get(manager, name, &netdev);

        switch (type) {
        case RTM_NEWLINK:
                if (netdev) {
                        /* netdev exists, so make sure the ifindex matches */
                        r = netdev_set_ifindex(netdev, message);
                        if (r < 0) {
                                log_netdev_warning_errno(netdev, r, "Could not process new link message for netdev, ignoring: %m");
                                netdev_enter_failed(netdev);
                                return 0;
                        }
                }

                if (!link) {
                        /* link is new, so add it */
                        r = link_new(manager, message, &link);
                        if (r < 0) {
                                log_warning_errno(r, "Could not process new link message: %m");
                                return 0;
                        }

                        r = link_update(link, message);
                        if (r < 0) {
                                log_link_warning_errno(link, r, "Could not process link message: %m");
                                link_enter_failed(link);
                                return 0;
                        }

                        if (link->manager->test_mode) {
                                log_link_debug(link, "Running in test mode, refusing to enter initialized state.");
                                link_set_state(link, LINK_STATE_UNMANAGED);
                                return 0;
                        }

                        /* Do not enter initialized state if we are enumerating. */
                        if (manager->enumerating)
                                return 0;

                        r = link_check_initialized(link);
                        if (r < 0) {
                                log_link_warning_errno(link, r, "Failed to check link is initialized: %m");
                                link_enter_failed(link);
                                return 0;
                        }
                } else {
                        r = link_update(link, message);
                        if (r < 0) {
                                log_link_warning_errno(link, r, "Could not process link message: %m");
                                link_enter_failed(link);
                                return 0;
                        }
                        if (r == 0)
                                return 0;

                        if (link->manager->test_mode) {
                                log_link_debug(link, "Running in test mode, refusing to configure interface.");
                                link_set_state(link, LINK_STATE_UNMANAGED);
                                return 0;
                        }

                        /* Do not configure interface if we are enumerating. */
                        if (manager->enumerating)
                                return 0;

                        r = link_reconfigure_impl(link, /* flags = */ 0);
                        if (r < 0) {
                                log_link_warning_errno(link, r, "Failed to reconfigure interface: %m");
                                link_enter_failed(link);
                                return 0;
                        }
                }
                break;

        case RTM_DELLINK:
                link_drop(link);
                netdev_drop(netdev);
                break;

        default:
                assert_not_reached();
        }

        return 1;
}

int link_getlink_handler_internal(sd_netlink *rtnl, sd_netlink_message *m, Link *link, const char *error_msg) {
        uint16_t message_type;
        int r;

        assert(m);
        assert(link);
        assert(error_msg);

        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
                return 0;

        r = sd_netlink_message_get_errno(m);
        if (r < 0) {
                log_link_message_warning_errno(link, m, r, "%s", error_msg);
                link_enter_failed(link);
                return 0;
        }

        r = sd_netlink_message_get_type(m, &message_type);
        if (r < 0) {
                log_link_debug_errno(link, r, "rtnl: failed to read link message type, ignoring: %m");
                return 0;
        }
        if (message_type != RTM_NEWLINK) {
                log_link_debug(link, "rtnl: received invalid link message type, ignoring.");
                return 0;
        }

        r = link_update(link, m);
        if (r < 0) {
                link_enter_failed(link);
                return 0;
        }

        return 1;
}

int link_call_getlink(Link *link, link_netlink_message_handler_t callback) {
        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL;
        int r;

        assert(link);
        assert(link->manager);
        assert(link->manager->rtnl);
        assert(callback);

        r = sd_rtnl_message_new_link(link->manager->rtnl, &req, RTM_GETLINK, link->ifindex);
        if (r < 0)
                return r;

        r = netlink_call_async(link->manager->rtnl, NULL, req, callback,
                               link_netlink_destroy_callback, link);
        if (r < 0)
                return r;

        link_ref(link);
        return 0;
}

static const char* const link_state_table[_LINK_STATE_MAX] = {
        [LINK_STATE_PENDING]     = "pending",
        [LINK_STATE_INITIALIZED] = "initialized",
        [LINK_STATE_CONFIGURING] = "configuring",
        [LINK_STATE_CONFIGURED]  = "configured",
        [LINK_STATE_UNMANAGED]   = "unmanaged",
        [LINK_STATE_FAILED]      = "failed",
        [LINK_STATE_LINGER]      = "linger",
};

DEFINE_STRING_TABLE_LOOKUP(link_state, LinkState);

int link_flags_to_string_alloc(uint32_t flags, char **ret) {
        _cleanup_free_ char *str = NULL;
        static const char* map[] = {
                [LOG2U(IFF_UP)]          = "up",             /* interface is up. */
                [LOG2U(IFF_BROADCAST)]   = "broadcast",      /* broadcast address valid. */
                [LOG2U(IFF_DEBUG)]       = "debug",          /* turn on debugging. */
                [LOG2U(IFF_LOOPBACK)]    = "loopback",       /* interface is a loopback net. */
                [LOG2U(IFF_POINTOPOINT)] = "point-to-point", /* interface has p-p link. */
                [LOG2U(IFF_NOTRAILERS)]  = "no-trailers",    /* avoid use of trailers. */
                [LOG2U(IFF_RUNNING)]     = "running",        /* interface RFC2863 OPER_UP. */
                [LOG2U(IFF_NOARP)]       = "no-arp",         /* no ARP protocol. */
                [LOG2U(IFF_PROMISC)]     = "promiscuous",    /* receive all packets. */
                [LOG2U(IFF_ALLMULTI)]    = "all-multicast",  /* receive all multicast packets. */
                [LOG2U(IFF_MASTER)]      = "master",         /* master of a load balancer. */
                [LOG2U(IFF_SLAVE)]       = "slave",          /* slave of a load balancer. */
                [LOG2U(IFF_MULTICAST)]   = "multicast",      /* supports multicast. */
                [LOG2U(IFF_PORTSEL)]     = "portsel",        /* can set media type. */
                [LOG2U(IFF_AUTOMEDIA)]   = "auto-media",     /* auto media select active. */
                [LOG2U(IFF_DYNAMIC)]     = "dynamic",        /* dialup device with changing addresses. */
                [LOG2U(IFF_LOWER_UP)]    = "lower-up",       /* driver signals L1 up. */
                [LOG2U(IFF_DORMANT)]     = "dormant",        /* driver signals dormant. */
                [LOG2U(IFF_ECHO)]        = "echo",           /* echo sent packets. */
        };

        assert(ret);

        for (size_t i = 0; i < ELEMENTSOF(map); i++)
                if (BIT_SET(flags, i) && map[i])
                        if (!strextend_with_separator(&str, ",", map[i]))
                                return -ENOMEM;

        *ret = TAKE_PTR(str);
        return 0;
}

static const char * const kernel_operstate_table[] = {
        [IF_OPER_UNKNOWN]        = "unknown",
        [IF_OPER_NOTPRESENT]     = "not-present",
        [IF_OPER_DOWN]           = "down",
        [IF_OPER_LOWERLAYERDOWN] = "lower-layer-down",
        [IF_OPER_TESTING]        = "testing",
        [IF_OPER_DORMANT]        = "dormant",
        [IF_OPER_UP]             = "up",
};

DEFINE_STRING_TABLE_LOOKUP_TO_STRING(kernel_operstate, int);

bool link_has_local_lease_domain(Link *link) {
        assert(link);

        return link->dhcp_server &&
                link->network &&
                link->network->dhcp_server_local_lease_domain &&
                !dns_name_is_root(link->network->dhcp_server_local_lease_domain);
}

systemd / systemd / 19520565317

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