Re: [PATCH net] net: ipv6: Fix a bug in ndisc_send_ns when netdev only has a global address

[David Miller <davem@davemloft.net>]

From: Su Yanjun <suyj.fnst@cn.fujitsu.com>
Date: Mon, 29 Jul 2019 10:49:51 +0800

> When we send mpls packets and the interface only has a
> manual global ipv6 address, then the two hosts cant communicate.
> I find that in ndisc_send_ns it only tries to get a ll address.
> In my case, the executive path is as below.
> ip6_output
>  ->ip6_finish_output
>   ->lwtunnel_xmit
>    ->mpls_xmit
>     ->neigh_resolve_output
>      ->neigh_probe
>       ->ndisc_solicit
>        ->ndisc_send_ns
> 
> In RFC4861, 7.2.2 says
> "If the source address of the packet prompting the solicitation is the
> same as one of the addresses assigned to the outgoing interface, that
> address SHOULD be placed in the IP Source Address of the outgoing
> solicitation.  Otherwise, any one of the addresses assigned to the
> interface should be used."
> 
> In this patch we try get a global address if we get ll address failed.
> 
> Signed-off-by: Su Yanjun <suyj.fnst@cn.fujitsu.com>

David, can you take a quick look at this?

Thank you.