Re: [RFC] The Linux kernel IPv6 stack don't follow the RFC 4942 recommendation

["François-Xavier Le Bail" <fx.lebail@yahoo.com>]

----- Original Message -----

> From: François-Xavier Le Bail <fx.lebail@yahoo.com>
> To: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
> Sent: Thursday, November 10, 2011 1:54 PM
> Subject: Re: [RFC] The Linux kernel IPv6 stack don't follow the RFC 4942 recommendation
> 
> ----- Original Message -----
>>  From: Eric Dumazet <eric.dumazet@gmail.com>
>>  To: François-Xavier Le Bail <fx.lebail@yahoo.com>
>>  Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
>>  Sent: Thursday, November 10, 2011 12:27 PM
>>  Subject: Re: [RFC] The Linux kernel IPv6 stack don't follow the RFC 
> 4942 recommendation
>> 
>>  Le jeudi 10 novembre 2011 à 02:58 -0800, François-Xavier Le Bail a
>>  écrit :
>>>   ----- Original Message -----
>>> 
>>>   > From: Eric Dumazet <eric.dumazet@gmail.com>
>>>   > To: François-Xavier Le Bail <fx.lebail@yahoo.com>
>>>   > Cc: "netdev@vger.kernel.org" 
> <netdev@vger.kernel.org>
>>>   > Sent: Saturday, November 5, 2011 10:30 AM
>>>   > Subject: Re: [RFC] The Linux kernel IPv6 stack don't follow 
> the 
>>  RFC 4942 recommendation
>>>   > 
>>>   > Le samedi 05 novembre 2011 à 01:39 -0700, François-Xavier Le Bail 
> a
>>>   > écrit :
>>>   > 
>>>   >> 
>>>   >>  I will study and test these options for my application 
> server
>>>   > 
>>>   > Here is a sample of use of the IPv4 part, an udpecho service that 
> use
>>>   > IP_PKTINFO and IP_RECVTOS/IP_TOS to be able to use multihomed 
> machine,
>>>   > and reflect TOS field as well.
>>>   > [. . .]
>>> 
>>>   Hi,
>>> 
>>>   I have updated the code for IPv6.
>>> 
>>>   When a UDP client send to an unicast address on a multihomed Linux 
> 3.0.0 
>>  host, from another host, it's OK.
>>>   For example :
>>>   setup 2001::1 on eth0, 2a01::1 on eth1.
>>>   send to 2001::1, recv from 2001::1.
>>>   send to 2a01::1, recv from 2a01::1.
>>> 
>>>   When the UDP client send to an Subnet-Router anycast address on a 
>>  multihomed Linux 3.0.0 host, from another host, it's KO.
>>>   send to 2001:: or 2a01::, the udpecho server display "sendmsg: 
> Invalid 
>>  argument".
>>> 
>>>   Any idea ?
>> 
>>  Could you describe the setup of this machine ?
>> 
>>  ip -6 addr
>>  ip -6 ro
> 
> The server has ipv6 forwarding on.
> 
> # ip -6 a
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 
>     inet6 ::1/128 scope host 
>        valid_lft forever preferred_lft forever
> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
>     inet6 2a01::1/64 scope global 
>        valid_lft forever preferred_lft forever
>     inet6 fe80::20c:29ff:fecc:bc43/64 scope link 
>        valid_lft forever preferred_lft forever
> 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
>     inet6 2001::1/64 scope global 
>        valid_lft forever preferred_lft forever
>     inet6 fe80::20c:29ff:fecc:bc4d/64 scope link 
>        valid_lft forever preferred_lft forever
> 
> # ip -6 r
> 2001::/64 dev eth1  proto kernel  metric 256 
> 2a01::/64 dev eth0  proto kernel  metric 256 
> fe80::/64 dev eth1  proto kernel  metric 256 
> fe80::/64 dev eth0  proto kernel  metric 256 
> default via 2001::2 dev eth1  metric 1024 
> 
> 2001::2 is the address of the other (client) host.

I put a printk in addrconf.c at the beginning of ipv6_get_saddr_eval function.
In th OK case : nothing is print.
In the KO case : many printk messages.

Any problem in RFC 3484 code ?

Thanks,
Francois-Xavier