[CentOS] Attempting to use tproxy on Centos 8 fails with 'No such file or directory'

[Nathan Coulson]

On 2019-10-15 12:12 p.m., Nathan Coulson wrote:
> I was working on a haproxy transparent proxy setup that we had working 
> on Centos 7 (iptables), but running into issues getting tproxy working 
> with NFTables on Centos 8.
>
> From https://www.kernel.org/doc/Documentation/networking/tproxy.txt,
>
> It should be a matter of:
>
> # nft add table filter
> # nft add chain filter divert "{ type filter hook prerouting priority 
> -150; }"
> # nft add rule filter divert meta l4proto tcp socket transparent 1 
> meta mark set 1 accept
>
> But when running the 3rd line (add rule), I get
>
> root at kryptonite [/lib/modules/4.18.0-80.11.2.el8_0.x86_64]# nft add 
> rule filter divert meta l4proto tcp socket transparent 1 meta mark set 
> 1 accept
> Error: Could not process rule: No such file or directory
> add rule filter divert meta l4proto tcp socket transparent 1 meta mark 
> set 1 accept
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
>
>
> (In attempting to resolve this, I did the following)
>
> modprobe nf_tproxy_ipv4
> modprobe nf_tproxy_ipv6
> modprobe nf_socket_ipv4
> modprobe nf_socket_ipv6
>
> I also noted that:
> nft add rule filter divert meta l4proto tcp  meta mark set 1 accept 
> (Removing socket transparent 1)
>
> does not exit with a failure.
>
> Also found https://bugzilla.redhat.com/show_bug.cgi?id=1651813, (which 
> did make reference to the nftables version 0.9.0 possibly missing 
> support, I have not tried compiling 0.9.1 yet,  but I find it curious 
> the entire line fails with 'socket transparent 1' making me wonder if 
> it is a missing module still)
>
>
Adding to this:  just did a loop through the netfilter modules to see if 
something was missing (no change)

for x in $(find /lib/modules/4.18.0-80.11.2.el8_0.x86_64  | grep 
netfilter | sed 's/.*netfilter.//' | sed 's/\.ko.*$//' | sort); do
echo ">>>>>>$x<<<<<<<<"
   modprobe $x
   nft add rule filter divert meta l4proto tcp socket transparent 1 meta 
mark set 1 accept
done


-- 
Nathan Coulson
System Administrator for Bravenet Web Services
www.bravenet.com