extensions/libip6t_length.man - maze/iptables - Git at Google

 This module matches the length of the IPv6 payload in octets, or range of it.
 IPv6 header itself isn't counted.
 .TP
 .BR "--length " "[!] \fIlength\fP[:\fIlength\fP]"
	This module matches the length of the IPv6 payload in octets, or range of it.
	IPv6 header itself isn't counted.
	.TP
	.BR "--length " "[!] \fIlength\fP[:\fIlength\fP]"