[LU-17006] socklnd: modify ksocklnd-config

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Labels: config socklnd
• Severity: 3
• Assignee: Serguei Smirnov
• Reporter: Serguei Smirnov

Description

To accomodate the topologies where the destination NID may be on a different subnet, it is proposed to setup linux routing as follows:

"10 ens3f0np0" >> /etc/iproute2/rt_tables
"20 ens3f1np1" >> /etc/iproute2/rt_tables
ip rule add from 10.85.160.146 table ens3f0np0
ip rule add from 10.85.160.147 table ens3f1np1
ip route add default via 10.85.160.1 dev ens3f0np0 table ens3f0np0
ip route add default via 10.85.160.1 dev ens3f1np1 table ens3f1np1

The difference between the above and what ksocklnd-config is setting up is in the "ip route add" command. ksocklnd-config script currently does this instead: 

ip route add 10.85.160.0/24 dev ens3f0np0 proto kernel scope link src 10.85.160.146 table ens3f0np0

This command is fine for making sure that traffic to destinations on the same subnet as the source goes out the specified interface, but doesn't cover the case when the destination happens to be on a different subnet. The proposed change makes sure that packets with 10.85.160.146 source IP always use ens3f0np0 no matter what the destination IP is.