Re: [PATCH net-next] ip6_tunnel: Allow rcv/xmit even if remote address is a local address

[David Miller <davem@davemloft.net>]

From: Shmulik Ladkani <shmulik@nsof.io>
Date: Sat, 21 Oct 2017 00:25:15 +0300

> From: Shmulik Ladkani <shmulik.ladkani@gmail.com>
> 
> Currently, ip6_tnl_xmit_ctl drops tunneled packets if the remote
> address (outer v6 destination) is one of host's locally configured
> addresses.
> Same applies to ip6_tnl_rcv_ctl: it drops packets if the remote address
> (outer v6 source) is a local address.
> 
> This prevents using ipxip6 (and ip6_gre) tunnels whose local/remote
> endpoints are on same host; OTOH v4 tunnels (ipip or gre) allow such
> configurations.
> 
> An example where this proves useful is a system where entities are
> identified by their unique v6 addresses, and use tunnels to encapsulate
> traffic between them. The limitation prevents placing several entities
> on same host.
> 
> Introduce IP6_TNL_F_ALLOW_LOCAL_REMOTE which allows to bypass this
> restriction.
> 
> Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>

Given this wasn't allowed for so long, making it configurable makes
sense.

Applied, thanks.