Re: [PATCH net-next] net: mctp: add MCTP_OPT_ROUTE_SRCADDR getsockopt

Hi Faizan,

Add a new socket option MCTP_OPT_ROUTE_SRCADDR that allows applications
to query which local EID the kernel would use as the source address
when sending to a given destination EID.

Applications such as PLDM need to advertise a local EID as the event
receiver address to remote endpoints. Previously this required a manual
multi-step lookup via the mctp tool (route show + addr show).
The kernel routing table is the authoritative
source for this mapping, so expose it directly via a socket option.

As I had asked earlier, can you elaborate on why this is needed over
choosing any local address? Is there a routing topology where this
would not work?

I'm not against the idea, we just need a fairly solidy justification
for adding user ABI that cannot be changed in future.

Cheers,


Jeremy