This is used to set the security mark value associated with the
packet for use by security subsystems such as SELinux.  It is
valid in the
.B security
table (for backwards compatibility with older kernels, it is also
valid in the
.B mangle
table). The mark is 32 bits wide.
.TP
\fB\-\-selctx\fP \fIsecurity_context\fP
