Re: Issues during assigning addresses on point to point interfaces

[Marek Behún]

On Sun, 6 Jun 2021 17:10:08 +0200
Pali Rohár <pali@xxxxxxxxxx> 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