diff --git a/src/net/ipv6/inet6.c b/src/net/ipv6/inet6.c
index 3c931ba..069cb63 100644
--- a/src/net/ipv6/inet6.c
+++ b/src/net/ipv6/inet6.c
@@ -8,6 +8,7 @@
 #include <string.h>
 
 #include "base/xalloc.h"
+#include "base/ipchecksum.h"
 #include "net/ipv6/inet6.h"
 #include "net/ipv6/ipv6.h"
 
@@ -166,22 +167,6 @@
 	return -1;
 }
 
-static uint16_t checksum(const void *_data, size_t len, uint16_t _sum)
-{
-	uint32_t sum = _sum;
-	const uint16_t *data = _data;
-
-	while (len > 1) {
-		sum += *data++;
-		len -= 2;
-	}
-	if (len)
-		sum += (*data & 0xFF);
-	while (sum > 0xFFFF)
-		sum = (sum & 0xFFFF) + (sum >> 16);
-	return sum;
-}
-
 typedef struct __attribute__((packed)) {
 	uint32_t ver_tc_flow;
 	uint16_t length;
@@ -213,15 +198,10 @@
 
 static unsigned ipv6_checksum(Ipv6Hdr *ip, unsigned type, size_t length)
 {
-	uint16_t sum;
-
 	// Length and protocol field for pseudo-header.
-	sum = checksum(&ip->length, 2, htonw(type));
+	uint16_t sum = ipchecksum(&ip->length, 2, ~htonw(type));
 	// src/dst for pseudo-header + payload.
-	sum = checksum(ip->src, 32 + length, sum);
-
-	// 0 is illegal, so 0xffff remains 0xffff
-	return sum == 0xffff ? sum : ~sum;
+	return ipchecksum(ip->src, 32 + length, sum);
 }
 
 static int ipv6_setup(Ipv6Pkt *p, NetDevice *dev, const Ipv6Address *daddr,
@@ -350,7 +330,6 @@
 static void _udpv6_recv(Ipv6Hdr *ip, void *_data, size_t len)
 {
 	UdpHdr *udp = _data;
-	uint16_t sum, n;
 
 	if (len < Udp_HdrLen)
 		printf("error: Bogus Header Len\n");
@@ -359,12 +338,12 @@
 	if (udp->checksum == 0xFFFF)
 		udp->checksum = 0;
 
-	sum = checksum(&ip->length, 2, htonw(HdrUdp));
-	sum = checksum(ip->src, 32 + len, sum);
-	if (sum != 0xFFFF)
+	uint16_t sum = ipchecksum(&ip->length, 2, ~htonw(HdrUdp));
+	sum = ipchecksum(ip->src, 32 + len, sum);
+	if (sum != 0)
 		printf("error: Checksum Incorrect\n");
 
-	n = ntohw(udp->length);
+	uint16_t n = ntohw(udp->length);
 	if (n < Udp_HdrLen)
 		printf("error: Bogus Header Len\n");
 	if (n > len)
@@ -401,9 +380,9 @@
 	if (icmp->checksum == 0xFFFF)
 		icmp->checksum = 0;
 
-	uint16_t sum = checksum(&ip->length, 2, htonw(HdrIcmpv6));
-	sum = checksum(ip->src, 32 + len, sum);
-	if (sum != 0xFFFF)
+	uint16_t sum = ipchecksum(&ip->length, 2, ~htonw(HdrIcmpv6));
+	sum = ipchecksum(ip->src, 32 + len, sum);
+	if (sum != 0)
 		printf("error: Checksum Incorrect\n");
 
 	if (icmp->type == Icmpv6_NdpNSolicit) {