"ecn" match support

modulename: xt_ecn.ko

configname: CONFIG_NETFILTER_XT_MATCH_ECN

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>Core Netfilter Configuration
└─>"ecn" match support
In linux kernel since version 3.1 (release Date: 2011-10-24)  
This option adds an "ECN" match, which allows you to match against
the IPv4 and TCP header ECN fields.

To compile it as a module, choose M here. If unsure, say N.

source code: