socram8888 / mod_mark

Apache2 module for retrieving the connection's SO_MARK value

mod_mark

Apache 2 module for retrieving connections's SO_MARK.

This module defines a new environment variable called SOCKET_MARK which can be accessed and processed from PHP and other content processors.

Installation

Apache's apxs module compiler must be available. On Debian this can be installed using:

sudo apt install apache-dev

Once available, the module can be built and installed using:

make
sudo make install
sudo service apache2 restart

Please note that for this to work, the tcp_fwmark_accept kernel flag must be set.

This change can be made temporarily for testing via:

sysctl net.ipv4.tcp_fwmark_accept=1

If desired, it can be made persistent by creating a configuration file:

cat <<'EOF' | sudo tee /etc/sysctl.d/50-accept-fwmark.conf
# Allow getsockopt(SO_MARK) to fetch netfilter-assigned marks
net.ipv4.tcp_fwmark_accept = 1
EOF
sudo sysctl -p /etc/sysctl.d/50-accept-fwmark.conf