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Date:   Thu, 24 Jun 2021 12:45:45 +0200
From:   Marek =?UTF-8?B?QmVow7pu?= <kabel@kernel.org>
To:     Pali =?UTF-8?B?Um9ow6Fy?= <pali@kernel.org>
Cc:     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,
        Nicolas Dichtel <nicolas.dichtel@6wind.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        Stephen Hemminger <stephen@networkplumber.org>,
        Phil Sutter <phil@nwl.cc>
Subject: Re: Issues during assigning addresses on point to point interfaces
Message-ID: <20210624124545.2b170258@dellmb>
In-Reply-To: <20210606151008.7dwx5ukrlvxt4t3k@pali>
References: <20210606151008.7dwx5ukrlvxt4t3k@pali>
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On Sun, 6 Jun 2021 17:10:08 +0200
Pali Roh=C3=A1r <pali@kernel.org> wrote:

> Hello!
>=20
> Seems that there is a bug during assigning IP addresses on point to
> point interfaces.
>=20
> Assigning just one local address works fine:
>=20
>     ip address add fe80::6 dev ppp1 --> inet6 fe80::6/128 scope link
>=20
> Assigning both local and remote peer address also works fine:
>=20
>     ip address add fe80::7 peer fe80::8 dev ppp1 ---> inet6 fe80::7
> peer fe80::8/128 scope link
>=20
> But trying to assign just remote peer address does not work. Moreover
> "ip address" call does not fail, it returns zero but instead of
> setting remote peer address, it sets local address:
>=20
>     ip address add peer fe80::5 dev ppp1 --> inet6 fe80::5/128 scope
> link
>=20

Adding some other people to Cc in order to get their opinions.

It seems this bug is there from the beginning, from commit
caeaba79009c2 ("ipv6: add support of peer address")
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?=
id=3Dcaeaba79009c2

Maybe some older user-space utilities use IFA_ADDRESS instead of
IFA_LOCAL, and this was done in order to be compatible with them?

Marek