iproute-extension breaks fwmark

[SriramScorp]

When adding fwmark rules using this extension, rules seem to have the same value upon listing. However, when rules are listed with the built-in iproute2 binary, they display the correct values. Current working option is to use this extension only for turning MPTCP on or off while falling back to the original, unmodified iproute2 for rule creation and selection.

root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# dpkg -l | grep iproute2
ii  iproute2                  4.20.0-2+deb10u1            armhf        networking and traffic control tools
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# which ip
/sbin/ip
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# ip -V
ip utility, iproute2-ss190107
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# ./ip/ip -V
ip utility, iproute2-ss181023
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# ./ip/ip rule add fwmark 5 table 5
root@raspi-mptcp:/tmp/iproute-mptcp# ./ip/ip rule add fwmark 6 table 6
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# ./ip/ip rule list 
0:	from all lookup local
32764:	from all fwmark 0x9076c lookup 6
32765:	from all fwmark 0x9076c lookup 5
32766:	from all lookup main
32767:	from all lookup default
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# ip rule list
0:	from all lookup local
32764:	from all fwmark 0x6 lookup 6
32765:	from all fwmark 0x5 lookup 5
32766:	from all lookup main
32767:	from all lookup default
root@raspi-mptcp:/tmp/iproute-mptcp# 

[matttbe]

Hi @SriramScorp,

Could you eventually compile a more recent version?

I don't see why this issue would come from the modifications we did to support the new multipath parameter for ip link.

Feel free to try master branch (or mptcp_v0.96 or mptcp_v0.95) but the upstream project recommendations is to use the latest version as older ones are no longer maintained and the latest one should still be compatible with old kernels.

[SriramScorp]

The kernel being used is the mptcp kernel built on a fairly recent RaspiOS (2021-01-11-raspios-buster-armhf.img).

root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# uname -r
5.4.83-MPTCP+
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# lsb_release -a
No LSB modules are available.
Distributor ID:	Raspbian
Description:	Raspbian GNU/Linux 10 (buster)
Release:	10
Codename:	buster
root@raspi-mptcp:/tmp/iproute-mptcp# 

Faced the issue when I built the extension from the latest commit of the default branch (mptcp_v0.95). After recompiling with the master branch, it seems to works just fine.

root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# ./ip/ip -V
ip utility, iproute2-5.15.0
root@raspi-mptcp:/tmp/iproute-mptcp# 
root@raspi-mptcp:/tmp/iproute-mptcp# ./ip/ip rule list
0:	from all lookup local
32764:	from all fwmark 0x6 lookup 6
32765:	from all fwmark 0x5 lookup 5
32766:	from all lookup main
32767:	from all lookup default
root@raspi-mptcp:/tmp/iproute-mptcp# 

I guess README should mention a recommendation to use master branch since it's currently not the default one.