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openwrt / odhcpd

This repository is a mirror of https://git.openwrt.org/?p=project/odhcpd.git. Pull requests will be accepted which will be merged in odhcpd.git
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odhcpd - Embedded DHCP/DHCPv6/RA Server & Relay

Abstract

odhcpd is a daemon for serving and relaying IP management protocols to configure clients and downstream routers. It tries to follow the RFC 6204 requirements for IPv6 home routers.

odhcpd provides server services for DHCP, RA, stateless and stateful DHCPv6, prefix delegation and can be used to relay RA, DHCPv6 and NDP between routed (non-bridged) interfaces in case no delegated prefixes are available.

Features

  1. Router Discovery support (solicitations and advertisements) with 2 modes server: RD server for slave interfaces a) automatic detection of prefixes, delegated prefix and default routes, MTU b) automatic reannouncement when changes to prefixes or routes occur

    relay: RD relay between master and slave interfaces a) support for rewriting announced DNS-server addresses in relay mode

  2. DHCPv6-support with 2 modes of operation server: stateless, stateful and PD-server mode a) stateless and stateful address assignment b) prefix delegation support c) dynamic reconfiguration in case prefixes change d) hostname detection and hosts-file creation

    relay: mostly standards-compliant DHCPv6-relay a) support for rewriting announced DNS-server addresses

  3. DHCPv4-support server: stateless and stateful mode

  4. Proxy for Neighbor Discovery messages (solicitations and advertisements) a) support for auto-learning routes to the local routing table b) support for marking interfaces "external" not proxying NDP for them and only serving NDP for DAD and for traffic to the router itself [Warning: you should provide additional firewall rules for security]

Compiling

odhcpd uses cmake:

Configuration

odhcpd uses a UCI configuration file in /etc/config/dhcp for configuration and may also receive information from ubus

Section of type odhcpd

Option Type Default Description legacy bool 0 Enable DHCPv4 if start but no dhcpv4 option set maindhcp bool 0 Use odhcpd as the main DHCPv4 service leasefile string DHCP/v6 lease/hostfile leasetrigger string Lease trigger script hostsfile string DHCP/v6 hostfile loglevel integer 6 Syslog level priority (0-7)

Sections of type dhcp (configure DHCP / DHCPv6 / RA / NDP service)

Option Type Default Description interface string logical OpenWrt interface ifname string physical network interface networkid string same as ifname compat. alias for ifname master bool 0 is a master interface for relaying

ra string disabled Router Advert service [disabled|server|relay|hybrid] dhcpv6 string disabled DHCPv6 service [disabled|server|relay|hybrid] dhcpv4 string disabled DHCPv4 service [disabled|server] ndp string disabled Neighbor Discovery Proxy [disabled|relay|hybrid]

dynamicdhcp bool 1 Dynamically create leases for DHCPv4 and DHCPv6 dhcpv4_forcereconf bool 0 Force reconfiguration by sending force renew message even if the client did not include the force renew nonce capability option (RFC6704) dhcpv6_assignall bool 1 Assign all viable DHCPv6 addresses in statefull mode; if disabled only the DHCPv6 address having the longest preferred lifetime is assigned dhcpv6_hostidlength integer 12 Host ID length of dynamically created leases, allowed values: 12 - 64 (bits). dhcpv6_na bool 1 DHCPv6 stateful addressing hands out IA_NA - Internet Address - Network Address dhcpv6_pd bool 1 DHCPv6 stateful addressing hands out IA_PD - Internet Address - Prefix Delegation dhcpv6_pd_min_len integer - Minimum prefix length to delegate with IA_PD (value is adjusted if needed to be greater than the interface prefix length). Range [1,62] router list Routers to announce accepts IPv4 only dns list DNS servers to announce accepts IPv4 and IPv6 dns_service bool 1 Announce the address of interface as DNS service if the list of dns is empty domain list Search domains to announce

leasetime string 12h DHCPv4 address leasetime start integer 100 DHCPv4 pool start limit integer 150 DHCPv4 pool size preferred_lifetime string 7d Value for the preferred lifetime for a prefix ra_default integer 0 Override default route 0: default, 1: ignore no public address, 2: ignore all ra_flags list other-config List of RA flags to be advertised in RA messages [managed-config other-config home-agent none] ra_slaac bool 1 Announce slaac for a prefix ra_offlink bool 0 Announce prefixes off-link ra_preference string medium Route(r) preference [medium|high|low] ra_maxinterval integer 600 Maximum time allowed between sending unsolicited RA ra_mininterval integer 200 Minimum time allowed between sending unsolicited RA ra_lifetime integer 1800 Value to be placed in Router Lifetime field of RA ra_useleasetime bool 0 Use configured leasetime as limit for the preferred and valid lifetime of a prefix ra_reachabletime integer 0 Reachable Time in milliseconds to be advertised in RA messages ra_retranstime integer 0 Retransmit Time in milliseconds to be advertised in RA messages ra_hoplimit integer 0 Current hoplimit to be advertised in RA messages ra_mtu integer - MTU to be advertised in RA messages ra_dns bool 1 Announce DNS configuration in RA messages (RFC8106) ra_pref64 string Announce PREF64 option [IPv6 prefix] for NAT64 prefix (RFC8781) ndproxy_routing bool 1 Learn routes from NDP ndproxy_slave bool 0 NDProxy external slave prefix_filter string ::/0 Only advertise on-link prefixes within [IPv6 prefix] the provided IPv6 prefix; others are filtered out. ntp list NTP servers to announce accepts IPv4 and IPv6

Sections of type host (static leases) Option Type Default Description ip string IP-Address to lease mac string MAC-address duid string DUID in base16 hostid string IPv6 host identifier name string Hostname leasetime string DHCPv4/v6 leasetime