Re: Issues during assigning addresses on point to point interfaces

On Sun, 6 Jun 2021 17:10:08 +0200
Pali Rohár [off-list ref] wrote:

Hello!

Seems that there is a bug during assigning IP addresses on point to
point interfaces.

Assigning just one local address works fine:

    ip address add fe80::6 dev ppp1 --> inet6 fe80::6/128 scope link

Assigning both local and remote peer address also works fine:

    ip address add fe80::7 peer fe80::8 dev ppp1 ---> inet6 fe80::7
peer fe80::8/128 scope link

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:

    ip address add peer fe80::5 dev ppp1 --> inet6 fe80::5/128 scope
link

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=caeaba79009c2

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