[Cerowrt-devel] ipv6 on comcast with 18.06.1

[Cerowrt-devel] ipv6 on comcast with 18.06.1

[Dave Taht]

Sigh. Once upon a time I used to test this stuff on comcast. So I
finally got around to deploying
a new 18.06 gateway and ipv6 is busted with comcast.


https://bugs.openwrt.org/index.php?do=details&task_id=1763

-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Mikael Abrahamsson]

On Mon, 1 Oct 2018, Dave Taht wrote:

> Sigh. Once upon a time I used to test this stuff on comcast. So I
> finally got around to deploying
> a new 18.06 gateway and ipv6 is busted with comcast.

Can you please email me output from "tcpdump -n -vvv -i <wan> port 546 or 
port 547 or icmp6" as your WAN is trying to get DHCPv6-PD ? Or if you dump 
that to a pcap and email it to me (or make it available somewhere for me 
to download).

I have 18.06.1 working with homenet on WRT1200AC,dual uplinks (two 
different vlans on WAN), getting dual stack from both ISPs, /56 from both, 
and both are announced out on LAN. I even configured bidirectional SQM 
with CAKE on each uplink (250/50 and 250/100 respectively) and it seems to 
do the right thing.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Dave Taht]

[-- Attachment #1: Type: text/plain, Size: 1081 bytes --]

Here you go! Going to go look at the firewall rules in a sec....
On Mon, Oct 1, 2018 at 8:45 AM Mikael Abrahamsson <swmike@swm.pp.se> wrote:
>
> On Mon, 1 Oct 2018, Dave Taht wrote:
>
> > Sigh. Once upon a time I used to test this stuff on comcast. So I
> > finally got around to deploying
> > a new 18.06 gateway and ipv6 is busted with comcast.
>
> Can you please email me output from "tcpdump -n -vvv -i <wan> port 546 or
> port 547 or icmp6" as your WAN is trying to get DHCPv6-PD ? Or if you dump
> that to a pcap and email it to me (or make it available somewhere for me
> to download).
>
> I have 18.06.1 working with homenet on WRT1200AC,dual uplinks (two
> different vlans on WAN), getting dual stack from both ISPs, /56 from both,
> and both are announced out on LAN. I even configured bidirectional SQM
> with CAKE on each uplink (250/50 and 250/100 respectively) and it seems to
> do the right thing.
>
> --
> Mikael Abrahamsson    email: swmike@swm.pp.se



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

[-- Attachment #2: comcast.cap --]
[-- Type: application/vnd.tcpdump.pcap, Size: 1726 bytes --]

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Dave Taht]

On Mon, Oct 1, 2018 at 8:58 AM Dave Taht <dave.taht@gmail.com> wrote:
>
> Here you go! Going to go look at the firewall rules in a sec....

I changed the rules to allow 547 and 546, no difference. I even
flushed the ipv6tables rules entirely,
and I'm running without that for a while. I can certainly imagine
comcast's dhcpv6 server giving up on me....

It's nice to know, btw, someone is still messing with homenet. Having
zero funding for
too many years burned me out on even trying. But I expected ipv6 to
keep working without
any more help from me! :(

> On Mon, Oct 1, 2018 at 8:45 AM Mikael Abrahamsson <swmike@swm.pp.se> wrote:
> >
> > On Mon, 1 Oct 2018, Dave Taht wrote:
> >
> > > Sigh. Once upon a time I used to test this stuff on comcast. So I
> > > finally got around to deploying
> > > a new 18.06 gateway and ipv6 is busted with comcast.
> >
> > Can you please email me output from "tcpdump -n -vvv -i <wan> port 546 or
> > port 547 or icmp6" as your WAN is trying to get DHCPv6-PD ? Or if you dump
> > that to a pcap and email it to me (or make it available somewhere for me
> > to download).
> >
> > I have 18.06.1 working with homenet on WRT1200AC,dual uplinks (two
> > different vlans on WAN), getting dual stack from both ISPs, /56 from both,
> > and both are announced out on LAN. I even configured bidirectional SQM
> > with CAKE on each uplink (250/50 and 250/100 respectively) and it seems to
> > do the right thing.
> >
> > --
> > Mikael Abrahamsson    email: swmike@swm.pp.se
>
>
>
> --
>
> Dave Täht
> CEO, TekLibre, LLC
> http://www.teklibre.com
> Tel: 1-669-226-2619



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Dave Taht]

hmm... bad udp checksum???

:/tmp# 09:12:17.404257 IP6 (flowlabel 0xdfff4, hlim 1, next-header UDP
(17) payload length: 159) fe80::20d:b9ff:fe43:a06c.546 >
ff02::1:2.547: [bad udp cksum 0x58f4 -> 0xc4a1!]
On Mon, Oct 1, 2018 at 9:12 AM Dave Taht <dave.taht@gmail.com> wrote:
>
> On Mon, Oct 1, 2018 at 8:58 AM Dave Taht <dave.taht@gmail.com> wrote:
> >
> > Here you go! Going to go look at the firewall rules in a sec....
>
> I changed the rules to allow 547 and 546, no difference. I even
> flushed the ipv6tables rules entirely,
> and I'm running without that for a while. I can certainly imagine
> comcast's dhcpv6 server giving up on me....
>
> It's nice to know, btw, someone is still messing with homenet. Having
> zero funding for
> too many years burned me out on even trying. But I expected ipv6 to
> keep working without
> any more help from me! :(
>
> > On Mon, Oct 1, 2018 at 8:45 AM Mikael Abrahamsson <swmike@swm.pp.se> wrote:
> > >
> > > On Mon, 1 Oct 2018, Dave Taht wrote:
> > >
> > > > Sigh. Once upon a time I used to test this stuff on comcast. So I
> > > > finally got around to deploying
> > > > a new 18.06 gateway and ipv6 is busted with comcast.
> > >
> > > Can you please email me output from "tcpdump -n -vvv -i <wan> port 546 or
> > > port 547 or icmp6" as your WAN is trying to get DHCPv6-PD ? Or if you dump
> > > that to a pcap and email it to me (or make it available somewhere for me
> > > to download).
> > >
> > > I have 18.06.1 working with homenet on WRT1200AC,dual uplinks (two
> > > different vlans on WAN), getting dual stack from both ISPs, /56 from both,
> > > and both are announced out on LAN. I even configured bidirectional SQM
> > > with CAKE on each uplink (250/50 and 250/100 respectively) and it seems to
> > > do the right thing.
> > >
> > > --
> > > Mikael Abrahamsson    email: swmike@swm.pp.se
> >
> >
> >
> > --
> >
> > Dave Täht
> > CEO, TekLibre, LLC
> > http://www.teklibre.com
> > Tel: 1-669-226-2619
>
>
>
> --
>
> Dave Täht
> CEO, TekLibre, LLC
> http://www.teklibre.com
> Tel: 1-669-226-2619



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Anderson, Charles R]

Is udp checksum offload enabled?  If so, tcpdump/wireshark won't see
the actual checksum and assume it is bad.

On Mon, Oct 01, 2018 at 09:12:57AM -0700, Dave Taht wrote:
> hmm... bad udp checksum???
> 
> :/tmp# 09:12:17.404257 IP6 (flowlabel 0xdfff4, hlim 1, next-header UDP
> (17) payload length: 159) fe80::20d:b9ff:fe43:a06c.546 >
> ff02::1:2.547: [bad udp cksum 0x58f4 -> 0xc4a1!]
> On Mon, Oct 1, 2018 at 9:12 AM Dave Taht <dave.taht@gmail.com> wrote:
> >
> > On Mon, Oct 1, 2018 at 8:58 AM Dave Taht <dave.taht@gmail.com> wrote:
> > >
> > > Here you go! Going to go look at the firewall rules in a sec....
> >
> > I changed the rules to allow 547 and 546, no difference. I even
> > flushed the ipv6tables rules entirely,
> > and I'm running without that for a while. I can certainly imagine
> > comcast's dhcpv6 server giving up on me....
> >
> > It's nice to know, btw, someone is still messing with homenet. Having
> > zero funding for
> > too many years burned me out on even trying. But I expected ipv6 to
> > keep working without
> > any more help from me! :(
> >
> > > On Mon, Oct 1, 2018 at 8:45 AM Mikael Abrahamsson <swmike@swm.pp.se> wrote:
> > > >
> > > > On Mon, 1 Oct 2018, Dave Taht wrote:
> > > >
> > > > > Sigh. Once upon a time I used to test this stuff on comcast. So I
> > > > > finally got around to deploying
> > > > > a new 18.06 gateway and ipv6 is busted with comcast.
> > > >
> > > > Can you please email me output from "tcpdump -n -vvv -i <wan> port 546 or
> > > > port 547 or icmp6" as your WAN is trying to get DHCPv6-PD ? Or if you dump
> > > > that to a pcap and email it to me (or make it available somewhere for me
> > > > to download).
> > > >
> > > > I have 18.06.1 working with homenet on WRT1200AC,dual uplinks (two
> > > > different vlans on WAN), getting dual stack from both ISPs, /56 from both,
> > > > and both are announced out on LAN. I even configured bidirectional SQM
> > > > with CAKE on each uplink (250/50 and 250/100 respectively) and it seems to
> > > > do the right thing.

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Dave Taht]

On Mon, Oct 1, 2018 at 9:29 AM Anderson, Charles R <cra@wpi.edu> wrote:
>
> Is udp checksum offload enabled?  If so, tcpdump/wireshark won't see
> the actual checksum and assume it is bad.

I imagine it is theoretically offloaded. I DO have an 18.06.1 arm box
now up that IS
getting dhcpv6-pd from comcast....

This arm box IS getting dhcpv6-pd from comcast correctly.

root@gw1:~# cat /etc/openwrt_release
DISTRIB_ID='OpenWrt'
DISTRIB_RELEASE='18.06.1'
DISTRIB_REVISION='r7258-5eb055306f'
DISTRIB_TARGET='ipq806x/generic'
DISTRIB_ARCH='arm_cortex-a15_neon-vfpv4'
DISTRIB_DESCRIPTION='OpenWrt 18.06.1 r7258-5eb055306f'
DISTRIB_TAINTS=''

My mips and x86_64 boxes aren't.

Otherwise based on my 4+ year old memory of this stuff, I don't see
anything immediately wrong
with the solicit.

(I updated the bug, too)

>
> On Mon, Oct 01, 2018 at 09:12:57AM -0700, Dave Taht wrote:
> > hmm... bad udp checksum???
> >
> > :/tmp# 09:12:17.404257 IP6 (flowlabel 0xdfff4, hlim 1, next-header UDP
> > (17) payload length: 159) fe80::20d:b9ff:fe43:a06c.546 >
> > ff02::1:2.547: [bad udp cksum 0x58f4 -> 0xc4a1!]
> > On Mon, Oct 1, 2018 at 9:12 AM Dave Taht <dave.taht@gmail.com> wrote:
> > >
> > > On Mon, Oct 1, 2018 at 8:58 AM Dave Taht <dave.taht@gmail.com> wrote:
> > > >
> > > > Here you go! Going to go look at the firewall rules in a sec....
> > >
> > > I changed the rules to allow 547 and 546, no difference. I even
> > > flushed the ipv6tables rules entirely,
> > > and I'm running without that for a while. I can certainly imagine
> > > comcast's dhcpv6 server giving up on me....
> > >
> > > It's nice to know, btw, someone is still messing with homenet. Having
> > > zero funding for
> > > too many years burned me out on even trying. But I expected ipv6 to
> > > keep working without
> > > any more help from me! :(
> > >
> > > > On Mon, Oct 1, 2018 at 8:45 AM Mikael Abrahamsson <swmike@swm.pp.se> wrote:
> > > > >
> > > > > On Mon, 1 Oct 2018, Dave Taht wrote:
> > > > >
> > > > > > Sigh. Once upon a time I used to test this stuff on comcast. So I
> > > > > > finally got around to deploying
> > > > > > a new 18.06 gateway and ipv6 is busted with comcast.
> > > > >
> > > > > Can you please email me output from "tcpdump -n -vvv -i <wan> port 546 or
> > > > > port 547 or icmp6" as your WAN is trying to get DHCPv6-PD ? Or if you dump
> > > > > that to a pcap and email it to me (or make it available somewhere for me
> > > > > to download).
> > > > >
> > > > > I have 18.06.1 working with homenet on WRT1200AC,dual uplinks (two
> > > > > different vlans on WAN), getting dual stack from both ISPs, /56 from both,
> > > > > and both are announced out on LAN. I even configured bidirectional SQM
> > > > > with CAKE on each uplink (250/50 and 250/100 respectively) and it seems to
> > > > > do the right thing.



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Michael Richardson]

[-- Attachment #1: Type: text/plain, Size: 845 bytes --]


Dave Taht <dave.taht@gmail.com> wrote:
    > hmm... bad udp checksum???

With some capture mechanisms, tcpdump gets bogus values because the hardware
did the checksums.  I wouldn't imagine that we have hardware checksum offload
on openwrt devices, but could be.

Or it's a real issue.

    > :/tmp# 09:12:17.404257 IP6 (flowlabel 0xdfff4, hlim 1, next-header UDP
    > (17) payload length: 159) fe80::20d:b9ff:fe43:a06c.546 > ff02::1:2.547:
    > [bad udp cksum 0x58f4 -> 0xc4a1!]  On Mon, Oct 1, 2018 at 9:12 AM Dave
    > Taht <dave.taht@gmail.com> wrote:

Did you capture with -i device, or -i any?

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        | network architect  [
]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 487 bytes --]

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Dave Taht]

On Mon, Oct 1, 2018 at 10:13 AM Michael Richardson <mcr@sandelman.ca> wrote:
>
>
> Dave Taht <dave.taht@gmail.com> wrote:
>     > hmm... bad udp checksum???
>
> With some capture mechanisms, tcpdump gets bogus values because the hardware
> did the checksums.  I wouldn't imagine that we have hardware checksum offload
> on openwrt devices, but could be.
>
> Or it's a real issue.

Checksums were good on the mips device I have not getting internal dhcpv6pd,
(dhcpv6 and slaac work on the external interface)...
but I didn't check them all, and it's possible the pool is exhausted.

Wasn't planning on doing this today! Hoped it was a firewall rule, frankly. :(

>
>     > :/tmp# 09:12:17.404257 IP6 (flowlabel 0xdfff4, hlim 1, next-header UDP
>     > (17) payload length: 159) fe80::20d:b9ff:fe43:a06c.546 > ff02::1:2.547:
>     > [bad udp cksum 0x58f4 -> 0xc4a1!]  On Mon, Oct 1, 2018 at 9:12 AM Dave
>     > Taht <dave.taht@gmail.com> wrote:
>
> Did you capture with -i device, or -i any?

device.

>
> --
> ]               Never tell me the odds!                 | ipv6 mesh networks [
> ]   Michael Richardson, Sandelman Software Works        | network architect  [
> ]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [
>


-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

Re: [Cerowrt-devel] ipv6 on comcast with 18.06.1

[Mikael Abrahamsson]

On Mon, 1 Oct 2018, Dave Taht wrote:

> On Mon, Oct 1, 2018 at 8:58 AM Dave Taht <dave.taht@gmail.com> wrote:
>>
>> Here you go! Going to go look at the firewall rules in a sec....
>
> I changed the rules to allow 547 and 546, no difference. I even
> flushed the ipv6tables rules entirely,
> and I'm running without that for a while. I can certainly imagine
> comcast's dhcpv6 server giving up on me....

Looking at your pcap file, there is no IPv6 to be had what so ever. No 
answer to RS or DHCPv6 SOLICIT. It doesn't get more basic than that.

> It's nice to know, btw, someone is still messing with homenet. Having 
> zero funding for too many years burned me out on even trying. But I 
> expected ipv6 to keep working without any more help from me! :(

Yes, your problem has nothing to do with basic IPv6 function. Windows 
Vista on launch day does the same you're doing, but since nothing is 
answering then you get no IPv6. So either your packets aren't making it to 
the Comcast upstream router, or it doesn't do any of the basics.

I thought this would be a PD problem or something, but this is more basic 
than that.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se