Ipv6 - problem with multicast addresses

[Juan Luis Baptiste]

I'm having similar problems with click ipv6/ipv4 transtor elements, as I said in a prior email to the list.

If the ipv6 module is loaded, ping6'ing ::172.25.0.3 and using a sniffer, I can see that the translator responds to the ipv6 machine with an destination unreachable message, but click translates the packet and send it to 172.25.0.3. This machine replies to the packet but again the translator responds to it with an destination unreachable message, and the packet never goes back to the ipv6 machine. If I leave off the ipv6 module, the behavior is similar, but the first destination unreachable message desappears (the one from the translator to the ipv6 machine), in any case the translator works! :-P .

Oh, and I'm not using the kernel module, but the user level tool and I'm having similar problems, so the problem I think is not related to the kernel.


bye

Juan Luis

-----Original Message-----
From: Brecht Vermeulen <brecht.vermeulen at rug.ac.be>
Date: Tue, 26 Feb 2002 05:19:59 +0100
To: click at amsterdam.lcs.mit.edu, frederik.scholaert at rug.ac.be
Subject: Re: Ipv6 - problem with multicast addresses


> 
> Hi all,
> 
> I did some further testing on the problem with IPv6 and multicast
> addresses for sollicitation messages (see mail of Frederik Scholaert).
> 
> So the problem is further compressed to:
> 
> host 1 (eth1)  ----    host 2 (eth 2)
> 
> I have 3 scenarios (with a fresh reboot of both machines in between)
> 
> 1) if we load on both hosts the ipv6 module, then it is possible to ping
> from host 1 to the link scope address of host 2. (everything is
> auto-magically configured, we do not nothing)
> ping6 fe80::250:baff:feca:2cae -I eth1  
> 
> on host 1, we see
> tcpdump: listening on eth1
> 04:42:52.504557 :: > ff02::1:ff07:acd4: icmp6: neighbor sol: who has
> fe80::250:baff:fe07:acd4
> 04:42:56.504584 fe80::250:baff:fe07:acd4 > ip6-allrouters: icmp6: router
> solicitation
> 04:43:00.504555 fe80::250:baff:fe07:acd4 > ip6-allrouters: icmp6: router
> solicitation
> 04:43:01.045766 fe80::250:baff:fe07:acd4 > ff02::1:ffca:2cae: icmp6:
> neighbor sol: who has fe80::250:baff:feca:2cae
> 04:43:01.045896 fe80::250:baff:feca:2cae > fe80::250:baff:fe07:acd4:
> icmp6: neighbor adv: tgt is fe80::250:baff:feca:2cae
> 04:43:01.045934 fe80::250:baff:fe07:acd4 > fe80::250:baff:feca:2cae:
> icmp6: echo request
> 04:43:01.046038 fe80::250:baff:feca:2cae > fe80::250:baff:fe07:acd4:
> icmp6: echo reply
> 04:43:02.044621 fe80::250:baff:fe07:acd4 > fe80::250:baff:feca:2cae:
> icmp6: echo request
> 04:43:02.044727 fe80::250:baff:feca:2cae > fe80::250:baff:fe07:acd4:
> icmp6: echo reply
> 04:43:03.044605 fe80::250:baff:fe07:acd4 > fe80::250:baff:feca:2cae:
> icmp6: echo request
> 
> So, this works.
> 
> 2) on host 1, we load the ipv6 module, on host 2 we load click with the
> following config:
> echo "FromDevice(eth1,1)->Print(yes)->Discard;"> /proc/click/config
> 
> and we do the same ping from host 1 to host 2 : nothing is printed by
> click (a tcpdump on host 1 shows 
> tcpdump: listening on eth1
> 04:51:06.010989 fe80::250:baff:fe07:acd4 > ff02::1:ffca:2cae: icmp6:
> neighbor sol: who has fe80::250:baff:feca:2cae
> 04:51:07.004349 fe80::250:baff:fe07:acd4 > ff02::1:ffca:2cae: icmp6:
> neighbor sol: who has fe80::250:baff:feca:2cae
> 04:51:08.004341 fe80::250:baff:fe07:acd4 > ff02::1:ffca:2cae: icmp6:
> neighbor sol: who has fe80::250:baff:feca:2cae
> 
> If we then however load ipv6 on host2, then the packets are printed in
> the syslog (without stopping click).
> We use the kernel level click module of Jan. 11th, 2002 with linux
> 2.2.19. The ethernet cards are DLINK DFE 530TX with via-rhine
> (non-polling) driver. I haven't tried with other cards yet.
> 
> 3) if we start on host 2 a tcpdump, load the ipv6 modules on both hosts
> and do the ping from host1 to host2, then it is the same as in scenario
> 2, no packets at host2, but tcpdump on host 1 sees the packets. If we
> stop tcpdump on host 2 and start tcpdump again, then we see the packets.
> (tried with libpcap 0.4a6/tcpdump 3.7.1 and libpcap 0.6.2/tcpdump 3.6.2,
> hope these are the correct version numbers).
> 
> 
> 
> If we look at the ethernet headers, we see
> tcpdump: listening on eth1
> 04:51:20.932240 0:50:ba:7:ac:d4 33:33:ff:ca:2c:ae 86dd 86:
> fe80::250:baff:fe07:acd4 > ff02::1:ffca:2cae: icmp6: neighbor sol: who
> has fe80::250:baff:feca:2cae
> 
> so, the destination MAC address is 33:33:... which is an ethernet
> multicast. 
> 
> So, scenario 2 seems very strange to me as I thought that click just
> took over the networking from Linux, but how comes then that it doesn't
> see any packet and that the loading of the ipv6 module makes that this
> works.
> Or could there be something broken with the multicast ethernet addresses
> and the card (although click is in promiscuous mode) ?
> 
> Our system is debian 2.2 (potato), kernel 2.2.19 with Click patch. (for
> all scenarios, Click is however not loaded in the 1st and 3rd scenario).
> 
> anyone any good idea (next possibilities I see is testing with other
> cards, 2.4.x kernels) ?
> 
> regards,
> Brecht
> 
> 
> 
> 
> 
> 
> 
> 
> Hi,
> 
> I'm experimenting with IPv6 in click. It works pretty well except for
> the
> fact that i'm not able to receive all-nodes or all-router multicast
> addresses in my click config.
> 
> My configuration is like this:
> 
> |HOST|-ETH1-fec0:0:0:1::65/64---ETH1-|CLICK
> ROUTER|-ETH2---fec0:0:0:2::66/64-ETH1-|HOST|
>                           [fec0:0:0:1::64/64]  [fec0:0:0:2::64/64]
> 
> 
> The IPv6-addresses fec0:0:0:1::64 and fec0:0:0:2::64 are not really
> assigned because IPv6 is not loaded on the click router.
> 
> When for instance the IPv6 Click config is loaded and i load IPv6 on the
> left host, the all-routers sollicitation packets don't seem to arrive at
> the click router. Or, when i do a ping fec0:0:0:2::66 on the left host,
> i
> see 'fec0:0:0:1::65 > ff02::1:ff00:64: icmp6: neighbor sol: who has
> fec0:0:0:1::64' -packets (leaving?) on eth1 of the left host, but they
> also do not seem to arrive at the click router. (I have a Print-element
> there after a FromDevice(eth1,1)-element and see nothing).
> 
> But when i first load the IPv6-module on the click-router and actually
> assign the fec0:0:0:1::64 and fec0:0:0:2::64 addresses, and then
> afterwards load click, i can ping through the click router.
> 
> I don't think it should have to be this way. Shouldn't i be able to run
> a
> IPv6 click config completely indepedent of IPv6 in the Linux kernel?
> 
> I use a click-version from january (from cvs), and kernel 2.2.19.
> 
> Can somebody help me on this matter?
> 
> regards,
> Frederik
> 
> 

-- 

Get your free email from www.linuxmail.org 


Powered by Outblaze