IPv6 & Linux - Current Status - Kernel and mandatory features

Contents

• Primary IPv6 features in the kernel
• Low level transport protocols
• User space daemons
• Security
• Mobility
• Stateful autoconfiguration
• Source address selection

Primary IPv6 features in the kernel

• Linux vanilla
• Kernel sources
• ftp://ftp.kernel.org/pub/linux/kernel/
• USAGI project (here you will find also the related kernel patches and ready-to-install kernel RPMs)
• http://www.linux-ipv6.org/
• Comparisons with test suites (http://www.tahi.org/)
• 2000-09: http://www.linux-ipv6.org/linux-test-en/index.html

Currently work/update in progress...

Feature	RFC/ Draft	Status Vanilla 2.4 (2.4.6)	Status USAGI 2.4 Extension	Status Vanilla 2.6	Status USAGI 2.6 Extension	Who is working on it	Link to sources / Additional comments
Raw socket		working		working
TCP		working		working
UDP		working		working
SCTP	RFC 2960	working (reported 2004-07-29)		working (reported 2004-07-29)		lksctp project	Stream Transmission Control Protocol Linux Kernel SCTP (lksctp) Project
ICMP
ICMPv6	RFC 2463	working		working
ICMP node information queries	draft-ietf-ipngwg-icmp-name-lookups	missing	working			USAGI
Address configuration
Stateless address autoconfiguration		working
Privacy extensions for stateless address autoconfiguration	RFC 3041 draft-ietf-ipngwg-temp-addresses-v2	missing	available				per interface switchable
Node discovery
Duplicate address detection		working		working
Neigbour discovery		bugfixed				USAGI	some (older) versions do not re-join all-node multicast address on network devices after down and up again
Neigbour discovery for inverse discovery	RFC 3122	missing
Router discovery		bugfixed				USAGI	some (older) versions do not re-join all-node multicast address on network devices after down and up again
Tunneling
Static tunneling (IPv6 encapsulated in IPv4)		working		working
Automatic tunneling of IPv4-comaptible IPv6 addresses		working		working
6over4		missing					Stig Venås do not have enough time for this
6to4		working		working
6to4 over UDP	draft-ietf-ngtrans-shipworm	missing
IPv{4,6} over IPv6			in progress			USAGI
ISATAP	draft-ietf-ngtrans-isatap	in progress?	available				Fred Templin, Nathan Lutchansky
Teredo		described working		described working			Use miredo http://www.simphalempin.com/dev/miredo/
ToS bit handling	RFC 2893 3.5	probably
ToS bit handling at Differentiated Services and Tunnels	RFC 2983
Bridging
Multilink subnets	draft-thaler-ipngwg-multilink-subnets	missing
Routing
Unicast routing		working
Multicast routing			on TODO			USAGI
Anycast routing		working					similar to unicast routing
Selections
Source address selection	draft-ietf-ipngwg-default-addr-select	in progress	improved, draft implementation in progress			Stig Venås	http://www.venaas.priv.no/ipv6/srcaddrsel.html kernel patch of the USAGI project more info below
Default router selection		working, but rather old
Security
IPsec Transport Mode AH			done	probably		USAGI
IPsec Transport Mode ESP			in progress	working		USAGI
IPsec Tunnel Mode AH			in progress	in progress		USAGI
IPsec Tunnel Mode ESP			in progress	working		USAGI
Firewalling		working (stateless paket filtering)		working (stateless paket filtering)	stateful packet filtering	USAGI & Netfilter team	Stateful packet filtering scheduled for vanilla kernel 2.6.15 (introducing protocol independend connection tracking support)
Mobility
Mobility support			in progress, only importing from/syncing with MIPL			MIPL
Options
hop-by-hop / jumbo payload		implemented
hop-by-hop / router alert		implemented
routing header		implemented
destination options			in progress, imported from MIPL			USAGI
QoS
Flow label support in kernel		still unknown
Flow label specific routing		still unknown
Flow label specific routing		still unknown				Wang Hui
Flow label support on application level		working?
Interface support / layer 2 transport protocols
Ethernet		working
Token-Ring						Mike Phillips
PPP	RFC 2472	working					with IPv6 enabled pppd working in 2.4 confirmed by me
ATM-PVC			in progress
ISDN CiscoHDLC							cannot test because of lack of a Cisco router
ISDN X.25							cannot test
ISDN HDLC using encapsulation ip		working					confirmed by me
ISDN HDLC using encapsulation syncppp and ipppd		not supported					confirmed by me, kernel doesn't support IPv6 in isdn_ppp.c: isdn_ppp: skipped unsupported protocol: 0xdd86. ipppd: i2.2 patch level 12
ISDN HDLC using encapsulation rawip		never capable					design issue, no type field available better called now rawipv4
SLIP and PLIP	RFC 1055	never capable					design issue, no type field available better called now SLIPv4
MPLS							URL: http://sf.net/projects/mpls-linux/
Still unsorted
Renumbering link net		working					with radvd
Multicast client		working
Anycast listening		missing
Path MTU discovery		bugfix in 2.4.6
sin6_socpe_id	like in RFC 2553		working			SEKIYA Yuji USAGI project	http://ftp2.v6.linux.or.jp/pub/Linux/kernel/patches/ ftp://ftp.nemoto.ecei.tohoku.ac.jp/pub/Net/IPv6/Patches/ kernel patch of the USAGI project discussions..., update of RFC is in progress
Divert sockets						Ilia Baldinei	http://www.anr.mcnc.org/~divert
specify next hop address	RFC 2292	missing
Traffic counters		missing					IPv6 data provided for SNMP

IPv6 packet filtering in kernel 2.4+

• URLs:
• Main: http://www.netfilter.org/

User space daemons

Security

Mobility 

Stateful autoconfiguration

DHCPv6 

Hierarchicly router (and clients) renumbering

• Possible with very new versions of radvd

Source address selection

I think Linux needs better IPv6 source address selection. When there are several global non-deprecated addresses, the current code (2.3.99-pre6) simply picks the first it finds, while I would like to choose one with longest common prefix compared to the destination address. This is described in draft-ietf-ipngwg-default-addr-select-00.txt paragraph 4 rule 6, and seems to be what for instance Solaris 8 does.
This is generally useful when one has several global IPv6 addresses (multihomed). An important special case is when one of the addresses is a 6to4 address (starting with 2002::/16). If the destination address is 6to4 the source address must also be 6to4. If the destionation is some other global address (3ffe or something) it must not be used.

It's necessary when an interface has both 6to4 and "normal" global addresses

• URL: http://www.venaas.priv.no/ipv6/srcaddrsel.html