"connmark" connection mark match support

configname: CONFIG_NETFILTER_XT_MATCH_CONNMARK

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>Core Netfilter Configuration
└─>"connmark" connection mark match support
In linux kernel since version 2.6.16.30-pre1 (release Date: 2006-09-22)  
This is a backwards-compat option for the user's convenience
(e.g. when running oldconfig). It selects
CONFIG_NETFILTER_XT_CONNMARK (combined connmark/CONNMARK module).