int link_set_mtu(Link *link, uint32_t mtu);
-int ipv4ll_configure(Link *link);
bool link_ipv4ll_enabled(Link *link, AddressFamilyBoolean mask);
-void dhcp4_release_old_lease(Link *link);
-int dhcp4_configure(Link *link);
-int dhcp4_set_client_identifier(Link *link);
-int dhcp4_set_promote_secondaries(Link *link);
-int dhcp6_request_prefix_delegation(Link *link);
-int dhcp6_configure(Link *link);
-int dhcp6_request_address(Link *link, int ir);
-int dhcp6_lease_pd_prefix_lost(sd_dhcp6_client *client, Link* link);
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int link_stop_clients(Link *link, bool may_keep_dhcp);
const char* link_state_to_string(LinkState s) _const_;