Re: rtsol

[Robert Swindells <rjs%fdy2.co.uk@localhost>]

Roy Marples wrote:
>On 21/10/2014 13:02, Robert Swindells wrote:
>> Roy Marples wrote:
>>> On 20/10/2014 22:06, Robert Swindells wrote:
>>>> What is the recommended way to replace rtsol(8) ?
>>>>
>>>> I have read the man page.
>>>>
>>>> My /etc/rc.conf contains the following:
>>>>
>>>> dhcpcd=YES
>>>> dhcpcd_flags="-B6 --nodhcp6 rtk0"
>>>>
>>>> At boot, dhcpcd prints that it has received the RA but then blocks,
>>>> prints an error that it has timed out and overwrites the
>>>> /etc/resolv.conf file with an empty one.
>>>>
>>>> It doesn't set the IPv6 address of the interface.
>>>
>>> Remove the B flag, that stops it forking to the background.
>>> You may need the ipv6ra_fork option if your RA doesn't provide the RDNSS
>>> option and you're not doing an IPv4 setup to avoid the timeout error.
>> 
>> The RA comes from rtadvd(8) on another NetBSD system, I needed the
>> ipv6ra_fork option.
>> 
>> It doesn't block or generate an error now.
>> 
>> It still doesn't set the IPv6 address though, which was the whole
>> point of running rtsol previously.
>
>rtadvd(8) supports setting RDNSS servers to populate resolv.conf with.
>So if you set that, you don't need the ipv6ra_fork.
>I think we could possibly set this by default if *only* running IPv6RS,
>ie disable IPv4 entirely and DHCPv6 as you have done.

>I don't know why it doesn't set an address though.
>Can you post the output of dhcpcd -dT6 --nodhcp rtk0 please?

dhcpcd[244]: version 6.5.1 starting
dhcpcd[244]: DUID 00:01:00:01:1b:ca:5e:a8:00:13:d4:bb:35:ed
dhcpcd[244]: rtk0: IAID f2:75:b2:f0
dhcpcd[244]: rtk0: delaying IPv6 router solictation for 0.4 seconds
dhcpcd[244]: rtk0: soliciting an IPv6 router
dhcpcd[244]: rtk0: sending Router Solicitation
dhcpcd[244]: rtk0: Router Advertisement from fe80::3e4a:92ff:fe77:c13c
dhcpcd[244]: rtk0: executing `/libexec/dhcpcd-run-hooks' TEST
interface=rtk0
pid=244
reason=TEST
skip_hooks='lookup-hostname  resolv.conf'
ifcarrier=up
ifflags=4294936643
ifmtu=1500
ifwireless=0
ra1_addr=2001:8b0:beb9:11c7:215:f2ff:fe75:b2f0/64
ra1_from=fe80::3e4a:92ff:fe77:c13c
ra1_prefix=2001:8b0:beb9:11c7::/64
ra_count=1
dhcpcd[244]: rtk0: No DHCPv6 instruction in RA
dhcpcd[244]: exited

There was also a kernel message printed when dhcpcd ran at boot:

nd6_dad_timer: called with non-tentative address 2001:8b0:beb9:11c7:215:f2ff:fe75:b2f0(rtk0)

>>> As you're setting one interface via the flags and not dhcpcd.conf I
>>> would recommend adding the M flag as well in-case you want to use any
>>> dhcpcd tools further down the road.
>> 
>> I just followed the suggestion in the new rtsol man page.
>> 
>> I think users are going to get bitten by this when upgrading to
>> NetBSD-7.
>
>The example in the man page is just for testing purposes, it even states
>that. For example, the --nodhcp6 flag is only intended for testing as
>the RA message will say if DHCPv6 should be started or not.

I don't want to run DHCPv6. I didn't need it before, why would I need it
now ?

>>> The resolv.conf part is tricky - because dhcpcd supports DNSSL and RDNSS
>>> options that need to expire it needs to be able to manage resolv.conf
>>> somehow. The solution is to either disable dhcpcd from writing to it at
>>> all (--nohook resolv.conf), setup your static config using
>>> resolvconf.conf or make the file immutable. Is this something we should
>>> document in resolv.conf(5)?
>> 
>> I would expect the default behaviour to be to not overwrite
>> resolv.conf on an error.
>
>This behaves like DHCP, DHCPv6 or a vpn link - expect resolv.conf to be
>modified. The entry for the interface is cleared on start, just like the
>addresses are cleared on a reboot. Hence the above comment I made.

It still fails POLA for me.

Robert Swindells