diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 4d9324c530a7..b64ce46afd3d 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1,4 +1,4 @@
-#       $NetBSD: Makefile,v 1.79 2001/05/23 15:59:58 sommerfeld Exp $
+#       $NetBSD: Makefile,v 1.80 2001/05/24 14:04:41 sommerfeld Exp $
 
 #	Makefile for section 9 (kernel function and variable) manual pages.
 
@@ -79,6 +79,8 @@ MLINKS+=extent.9 extent_create.9 extent.9 extent_destroy.9 \
 MLINKS+=fetch.9 fubyte.9 fetch.9 fuibyte.9 fetch.9 fusword.9 \
 	fetch.9 fuswintr.9 fetch.9 fuword.9 fetch.9 fuiword.9
 MLINKS+=humanize_number.9 format_bytes.9
+MLINKS+=in4_cksum.9 in_cksum.9 \
+	in4_cksum.9 in6_cksum.9
 MLINKS+=kprintf.9 printf.9 kprintf.9 sprintf.9 kprintf.9 snprintf.9 \
 	kprintf.9 vprintf.9 kprintf.9 vsprintf.9 kprintf.9 vsnprintf.9 \
 	kprintf.9 uprintf.9 kprintf.9 ttyprintf.9 \
diff --git a/share/man/man9/in4_cksum.9 b/share/man/man9/in4_cksum.9
index 4344c69fecc7..e90740065d40 100644
--- a/share/man/man9/in4_cksum.9
+++ b/share/man/man9/in4_cksum.9
@@ -1,4 +1,4 @@
-.\"	$NetBSD: in4_cksum.9,v 1.2 2001/05/23 18:49:59 wiz Exp $
+.\"	$NetBSD: in4_cksum.9,v 1.3 2001/05/24 14:04:41 sommerfeld Exp $
 .\"
 .\" Copyright (c) 2001 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -35,20 +35,30 @@
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
 .Dd May 22, 2001
-.Dt in4_cksum 9
+.Dt in_cksum 9
 .Os
 .Sh NAME
-.Nm in4_cksum
-.Nd compute checksum for IPv4 packets
+.Nm in_cksum ,
+.Nm in4_cksum ,
+.Nm in6_cksum
+.Nd compute Internet checksum
 .Sh SYNOPSIS
 .Ft uint16_t
+.Fn in_cksum "struct mbuf *m" "int len"
+.Ft uint16_t
 .Fn in4_cksum "struct mbuf *m" "uint8_t nxt" "int off" "int len"
+.Ft uint16_t
+.Fn in6_cksum "struct mbuf *m" "uint8_t nxt" "int off" "int len"
 .Sh DESCRIPTION
+These functions are used to compute the ones-complement checksum
+required by IP and IPv6.
 The
 .Fn in4_cksum
-function is used to compute the ones-complement checksum required by the
-.Xr inet 4
-protocol family over a range of bytes starting at
+function is used to compute the transport-layer checksum required by
+.Xr tcp 4
+and
+.Xr udp 4
+over a range of bytes starting at
 .Fa off
 and continuing on for
 .Fa len
@@ -60,25 +70,50 @@ If the
 parameter is non-zero, it is assumed to be an IP protocol number.
 It is also assumed that the data within
 .Fa m
-starts with an ip header; a pseudo-header is constructed as specified
+starts with an IP header, and the transport-layer header starts at 
+.Fa off ; 
+a pseudo-header is constructed as specified
 in RFC768 and RFC793, and the pseudo-header is prepended to the data
 covered by the checksum.
 .Pp
-This function is almost always performance critical and should be
-reimplemented in assembler or optimized C for each platform; use of
-repeated full-width add-with-carry followed by reduction of the sum to
-a 16 bit width usually leads to best results.
-.Sh RETURN VALUES
+The 
+.Fn in6_cksum
+function is similar; if 
+.Fa nxt 
+is non-zero, it is assumed that 
+.Fa m
+starts with an IPv6 header, and that the transport-layer header starts
+after
+.Fa off
+bytes.
+.Pp
 The
-.Fn in4_cksum
-function returns the computed checksum value.
+.Fn in_cksum
+function is equivalent to
+.Fn in4_cksum "m" "0" "0" "len" .
+.Pp
+These functions are always performance critical and should be
+reimplemented in assembler or optimized C for each platform; when
+available, use of repeated full-width add-with-carry followed by
+reduction of the sum to a 16 bit width usually leads to best results.
+See RFC's 1071, 1141, 1624, and 1936 for more information about
+efficient computation of the internet checksum.
+.Sh RETURN VALUES
+All three functions return the computed checksum value.
 .Sh SEE ALSO
 .Xr inet 4 ,
-.Xr tcp 4 ,
-.Xr udp 4 ,
+.Xr inet6 4 ,
+.Xr mbuf 9 ,
 .Xr protocols 5 ,
-.Xr mbuf 9
+.Xr tcp 4 ,
+.Xr udp 4
 .Sh STANDARDS
+These functions implement the Internet transport-layer checksum as specified 
+in RFC768, RFC793, and RFC2460.
+.Sh BUGS
 The
-.Fn in4_cksum
-function implements the checksum specified in RFC768 and RFC793.
+.Fn in6_cksum
+function currently requires special handling of link-local addresses
+in the pseudo-header due to the use of embedded scope-id's within
+link-local addresses.
+