NetBSD/sys/netinet6/TODO

KAME/NetBSD integration TODOs
$NetBSD: TODO,v 1.12 2000/02/05 18:11:41 itojun Exp $
Jun-ichiro itojun Hagino <itojun@itojun.org>


This file talks about issues/TODOs in KAME/NetBSD integration.
For details about original KAME distribution, please refer to
sys/netinet6/IMPLEMENTATION, or documents in KAME distribution.


KERNEL 
======
* net/if_types.h

IFT_GIF and IFT_FAITH are not defined in IANA assignment, but we need to
define these two (they are essential).  If it is prohibited to define these,
where should we check to get interface type?  if_xname?

* ATM PVC support in Adaptec/ENI ATM driver

Is it MI enough?  If not, would you like it to be removed from the tree?
Actually this is quite useful (we use it in Japanese ATM PVC leased line
service and is quite stable).

* mbuf pullup consideration

KAME IPv6 onion-peeling routine assumes that headers are contiguous on
mbufs.  For this we impose little restriction on drivers (namely,
MINCLSIZE has been modified for this).  From stats we gathered it has no
impact on performance (maybe better due to less m_pullup), but some of
you may not like this (you may hate deep-copy code in net/if_loop.c).
We may need to implement safer way, something similar to m_pullup().
I have an idea but I still need some time for this.  I'll test this in
KAME tree and then will bring it to NetBSD.
(NOTE: m_pullup is not very useful for IPv6 as the chained header length
can easily exceed MHLEN.  Remember, IPv6 header itself already occupies 40
bytes)

KAME team is doing experiments with m_pulldown().  will migrate to m_pulldown()
after stabilization.  working nicely but need more tests and code reviews.

* ipsec socket pointer

We currently reuse m_pkthdr.rcvif for ipsec socket pointer, and ipf and
other code does not like this.

It is planned to add m->m_pkthdr.aux (pointer to mbuf chain) to carry around
extra information for IPsec and other cases.

* gre/ipip compatibility

Hope I did not break any of these...  Could someone check?

* mbuf flags

KAME code introduces 5 mbuf flags, which should be decreased.  M_ANYCAST6
is local to IPv6 code so it should be M_PROTO0 or something like that.
Others (IPsec items) are used across IPv4 and IPv6 so they cannot be in
M_PROTO0 kind of thing.

When we switch to full m->m_pkthdr.aux support, we don't need IPsec related
flags in m->m_flags.

* use of xx_control() from kernel

xx_control() are designed to be called from userland process, not
from within the kernel.  Calling xx_control() from interrupt context would
cause various problems, like M_WAIT/NOWAIT issue, spl issue and others.
we need to clean it up.  The right thing to happen is to split those
necessary functions into (1) called-from-userland function, (2) called-from-
interrupt function, and (3) common backend which shares as much code as
possible.  in6_prefix.c is the offending portion.

* more LP64 friendliness checking

* scoped address printing

KAME implements extended format for link-local address printing, like
"fe80::1@lo0".  After long debate, IETF ipngwg will pick "lo0%fe80::1" as
standard one (picked "%" for avoiding conflict with "user@host" notation).
We'll need to update the support before the release.

* PRC_IF{UP,CHANGE}

We have some hook in sys/net/if.c for IPv6, for detecting (1) when interface
bringed up, and (2) when interface MTU changes.  These hooks should be
removed by introducing PRC_IF{UP,CHANGE}.


USERLAND
========
* pim6dd/pim6sd licensing

pim6dd/pim6sd license issue should be clarified, just like we need
clarification for mroute6d.

* IPv6-support in resolvers and libraries

Dual stack resolver code is from KAME.  The change may not be compatible with
future bind8 code, so we may have to merge future bind8 carefully.
(or we should volunteer for bind8 improvements)

At this moment IPv6 support in lib/libc/net/* is implemented in very
conservative way so that it will not break existing codebase.

* -DINET6, -DIPSEC

Where should we define -DINET6?  Should it be global option like 
EXPORTABLE_SYSTEM=1 (in /etc/mk.conf), or local option defined somewhere?
(some people may need a binary tree with no IPv6 support at all, for
smaller footprint)

At this moment -DINET6 is placed in each of leaf directory Makefiles,
and there's no global option for enabling/disabling userland IPv6/IPsec
support.  Since we ship single binary tree we want to ship them enabled
by default.

* more IPv6 support

X11, NFS, RPC, whatever.