doc: add ifctrstat(8) manpage

Makefile

@@ -127,7 +127,8 @@ install: all
 MANPAGES_8 = \
 	doc/ifquery.8 \
 	doc/ifup.8 \
-	doc/ifdown.8
+	doc/ifdown.8 \
+	doc/ifctrstat.8
 
 MANPAGES_5 = \
 	doc/interfaces.5

doc/ifctrstat.scd

@@ -0,0 +1,39 @@
+ifctrstat(8)
+
+# NAME
+
+ifctrstat - display interface statistics
+
+# SYNOPSIS
+
+*ifctrstat* [<_options_>...] <_interface_> <_counter_>
+
+*ifctrstat* [<_options_>...] -L|--list
+
+# DESCRIPTION
+
+*ifctrstat* is used to query interface statistic counters in
+a kernel-agnostic way.  This is useful for heterogenous
+environments where multiple kernels may be in use.
+
+# OPTIONS
+
+*-h, --help*
+	Display supported options to ifctrstat.
+
+*-n, --no-label*
+	Display the requested counter without its label.
+
+*-L, --list*
+	List available counters on this system.
+
+*-V, --version*
+	Print the ifupdown-ng version and exit.
+
+# SEE ALSO
+
+*ifquery*(8)
+
+# AUTHORS
+
+A. Wilcox <awilfox@adelielinux.org>