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Reply-To: nicolas.dichtel@6wind.com
Subject: Re: Issues during assigning addresses on point to point interfaces
To:     =?UTF-8?Q?Pali_Roh=c3=a1r?= <pali@kernel.org>
Cc:     =?UTF-8?Q?Marek_Beh=c3=ban?= <kabel@kernel.org>,
        netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        linux-kernel@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        Stephen Hemminger <stephen@networkplumber.org>,
        Phil Sutter <phil@nwl.cc>
References: <20210606151008.7dwx5ukrlvxt4t3k@pali>
 <20210624124545.2b170258@dellmb>
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 <20210625084031.c33yovvximtabmf4@pali>
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 <20210625152737.6gslduccvguyrr77@pali>
From:   Nicolas Dichtel <nicolas.dichtel@6wind.com>
Organization: 6WIND
Message-ID: <c4b854ef-6646-7ae8-b4a7-cb04b7b73222@6wind.com>
Date:   Fri, 25 Jun 2021 17:32:08 +0200
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Le 25/06/2021 à 17:27, Pali Rohár a écrit :
[snip]
>>> Hello Nicolas!
>>>
>>> See my original email where I put also rtnetlink packets (how strace see
>>> them). Seems that there is a bug in handling them (or bug in iproute2)
>>> as setting just peer (remote) IPv6 address is ignored:
>>> https://lore.kernel.org/netdev/20210606151008.7dwx5ukrlvxt4t3k@pali/
>>>
>>> Do you have any idea if this is affected by that "issue in the uAPI"?
>>> And what is the way how to fix it?
>> What about forcing IFA_LOCAL address to :: in your case?
> 
> It does not work. ip address returns error:
> 
>     $ sudo ip address add :: peer fe80::8 dev ppp0
>     RTNETLINK answers: Cannot assign requested address
So this trick could probably be used to handle your case, without breaking
anything, as it's not a valid command today.


Regards,
Nicolas