Re: [PATCH net] net: ipv6: Fix ping to link-local addresses.

On 8/9/16 1:01 AM, Erik Kline wrote:

On 9 August 2016 at 14:20, David Miller [off-list ref] wrote:

quoted

From: Lorenzo Colitti <redacted>
Date: Tue, 9 Aug 2016 10:00:25 +0900

quoted

Note that pretty much every sendmsg codepath allows other data to take
precedence over sk_bound_dev_if:

- udpv6_sendmsg: if sin6_scope_id specified on a scoped address
- rawv6_sendmsg: if sin6_scope_id specified on a scoped address
- l2tp_ip6_sendmsg: if sin6_scope_id specified on a scoped address
- ip_cmsg_send: if IP_PKTINFO or IPV6_PKTINFO specified

What should I do about those? -EINVAL? Ignore the conflicting data? Leave as is?

That's a good point, I guess this needs some more thought.

I could see a point of view that says when bound_if is in play sending
to destinations on/via other interfaces--by any mechanism--should
effectively get ENETUNREACH (or something).

VRF uses this capability to send on an enslaved interface. ie., socket is bound to VRF device to limit packets to that L3 domain and then uses PKTINFO to force a packet out a particular interface.