# DHCPv4 implementation for Zephyr # Copyright (c) 2016 Intel Corporation. # Copyright (c) 2024 Nordic Semiconductor ASA # # SPDX-License-Identifier: Apache-2.0 config NET_DHCPV4 bool "DHCPv4 client" select NET_MGMT select NET_MGMT_EVENT select NET_MGMT_EVENT_INFO if NET_IPV4_ACD depends on NET_IPV4 && NET_UDP if NET_DHCPV4 module = NET_DHCPV4 module-dep = NET_LOG module-str = Log level for DHCPv4 client module-help = Enable debug diagnostic from DHCPV4 client. source "subsys/net/Kconfig.template.log_config.net" config NET_DHCPV4_INITIAL_DELAY_MAX int "Maximum time out for initial discover request" depends on NET_DHCPV4 default 10 range 2 10 help As per RFC2131 4.1.1, we wait a random period between 1 and 10 seconds before sending the initial discover. config NET_DHCPV4_OPTION_CALLBACKS bool "Option callbacks" depends on NET_DHCPV4 help If set, custom callbacks for arbitrary DHCP options can be added. These can be used to support otherwise DHCP options not used by the rest of the system. config NET_DHCPV4_MAX_REQUESTED_OPTIONS int "Maximum number of requested options" depends on NET_DHCPV4 && NET_DHCPV4_OPTION_CALLBACKS default 10 range 3 $(UINT8_MAX) help Maximum number of requested options that can be added to the DHCPv4 request message. The options are added using the net_dhcpv4_add_option_callback() API. config NET_DHCPV4_OPTION_CALLBACKS_VENDOR_SPECIFIC bool "Encapsulated vendor specific option callbacks" depends on NET_DHCPV4 select NET_DHCPV4_OPTION_CALLBACKS help If set, custom callbacks for encapsulated vendor-specific information in DHCP option 43 can be added. config NET_DHCPV4_ACCEPT_UNICAST bool "Accept unicast DHCPv4 traffic" depends on NET_DHCPV4 default y help If set, the network stack will accept unicast DHCPv4 responses from servers, before the assigned address is configured on the interface. config NET_DHCPV4_VENDOR_CLASS_IDENTIFIER bool "Send vendor class identifier in DHCPv4 request" depends on NET_DHCPV4 help If set, the network stack will include the specified string in the DHCPv4 vendor class identifier option in the DHCPv4 request. config NET_DHCPV4_VENDOR_CLASS_IDENTIFIER_STRING string "Vendor class identifier" depends on NET_DHCPV4_VENDOR_CLASS_IDENTIFIER default "" help The string to include in the DHCPv4 vendor class identifier option in the DHCPv4 request. config NET_DHCPV4_OPTION_NTP_SERVER bool "Use NTP server from DHCPv4 option and save it in the net_if" default y depends on SNTP help If this option is set, then the NTP server can be set from the DHCPv4 option. config NET_DHCPV4_OPTION_DNS_ADDRESS bool "Use DNS server from DHCPv4 option and save it in the DNS resolver default context" default y depends on DNS_RESOLVER help If this option is set, then the DNS server can be set from the DHCPv4 option. endif # NET_DHCPV4 config NET_DHCPV4_SERVER bool "DHCPv4 server" depends on NET_IPV4 && NET_UDP select NET_SOCKETS select NET_SOCKETS_SERVICE if NET_DHCPV4_SERVER module = NET_DHCPV4_SERVER module-dep = NET_LOG module-str = Log level for DHCPv4 server module-help = Enables DHCPv4 server output debug messages source "subsys/net/Kconfig.template.log_config.net" config NET_DHCPV4_SERVER_INSTANCES int "Maximum number of DHCPv4 server instances" default 1 help Maximum number of DHCPv4 server instances supported by the system. Each network interface that wants to act as a DHCPv4 server requires a separate instance. config NET_DHCPV4_SERVER_ADDR_COUNT int "Number of IPv4 addresses that can be assigned by the server" default 4 help Maximum number of IPv4 addresses that can be assigned by the DHCPv4 server instance. The base IPv4 address in the address pool is provided at runtime, during server initialization. Consecutive addresses in the pool have the lowest address octet incremented. config NET_DHCPV4_SERVER_ADDR_LEASE_TIME int "Lease time for IPv4 addresses assigned by the server (seconds)" range 0 $(UINT32_MAX) default 86400 help Lease time in seconds for IPv4 addresses assigned by the server. The lease time determines when the IPv4 address lease expires if the client does not renew it. config NET_DHCPV4_SERVER_ADDR_DECLINE_TIME int "The time IPv4 addresses remains blocked after conflict detection (seconds)" range 0 $(UINT32_MAX) default 86400 help In case IPv4 address becomes blocked (either because of receiving Decline message or due to ICMP probe detecting conflict), the address can no longer be assigned. This timeout specifies how long the address remains in the Declined state. Note, that the server may try to reuse the oldest declined address in case it runs out of free addresses to assign. config NET_DHCPV4_SERVER_ICMP_PROBE_TIMEOUT int "Timeout for ICMP probes sent by the server (milliseconds)" range 0 60000 default 1000 help DHCPv4 server will probe the offered IP address (send ICMP echo request) and wait for the time specific by this config before offering the address. If set to 0, ICMP probing will be disabled. config NET_DHCPV4_SERVER_NAK_UNRECOGNIZED_REQUESTS bool "Reply with NAK for DHCP Requests from clients we do not recognize" default y help Zephyr's DHCPv4 server does not implement persistent storage of address leases. As a result, all leases are lost on reboot, which can cause delays with clients starting in INIT-REBOOT state and thus sending (potentially several) Requests before attempting full Discover-Request procedure. Enabling this config will violate the RFC in this regard, as instead of staying silent for unrecognized Request messages, the server will send a NAK, informing the client it should proceed with a full procedure. config NET_DHCPV4_SERVER_OPTION_DNS_ADDRESS string "DNS Server address" default DNS_SERVER1 if DNS_SERVER_IP_ADDRESSES default "" help This configuration option specifies the DNS server address that the DHCPv4 server should provide to clients when they request an IP address. The DHCPv4 server adds this DNS server address in the DHCP offer and acknowledgment messages sent to the clients, allowing them to use the specified DNS server for name resolution. config NET_DHCPV4_SERVER_OPTION_ROUTER bool "Set the router option in the DHCP server response" default y help If enabled, set the DHCP router option pointing to the interface own gateway address in responses from the DHCP server. This can be disabled so that the client does not try to forward traffic to our device. endif # NET_DHCPV4_SERVER