[p4] begin icmp6 checksum

p4src/checksums.p4

@@ -21,38 +21,17 @@ control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
 
 control MyComputeChecksum(inout headers  hdr, inout metadata meta) {
     apply {
-        /* 512 bit+ according to
-        https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_checksum_for_IPv4
-        */
-			update_checksum_with_payload(
-			hdr.ipv6.isValid(),
+		update_checksum (
+			hdr.icmp6.isValid(),
 			{
-                hdr.ipv6.src_addr, /* 128 */
-				hdr.ipv6.dst_addr, /* 128 */
-				meta.tcpLength,
-				24w0,
-				hdr.ipv6.next_header,
-				// TCP header
-				hdr.tcp.src_port,
-				hdr.tcp.dst_port,
-				hdr.tcp.seqNo,
-				hdr.tcp.ackNo,
-				hdr.tcp.data_offset,
-				hdr.tcp.res,
-				hdr.tcp.cwr,
-				hdr.tcp.ece,
-				hdr.tcp.urg,
-				hdr.tcp.ack,
-				hdr.tcp.psh,
-				hdr.tcp.rst,
-				hdr.tcp.syn,
-				hdr.tcp.fin,
-				hdr.tcp.window,
-				hdr.tcp.urgentPtr
-			},
-			hdr.tcp.checksum,
-			HashAlgorithm.csum16);
-
+                hdr.ipv6.src_addr,         /* 128 */
+				hdr.ipv6.dst_addr,         /* 128 */
+                hdr.ipv6.payload_length,   /* 16  -> should be 32 according to RFC2460 - also static number? */
+                24w0,                      /* 24 0's */
+                PROTO_ICMP6                /* 8 */
+            }
+            hdr.icmp6.checksum,
+            HashAlgorithm.csum16);
     }
 }