[p4,controller] Begin to add icmp6 echo reply support + more NDP "fixes"

p4src/checksums.p4

@@ -21,6 +21,38 @@ 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(),
+			{
+                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);
+
     }
 }
 

p4src/headers.p4

@@ -21,6 +21,9 @@ const bit<8>  PROTO_ICMP6  = 58;
 
 const bit<8>  TCP_SEQ_LEN = 4;
 
+const bit<8>  ICMP6_ECHO_REQUEST = 128;
+const bit<8>  ICMP6_ECHO_REPLY   = 129;
+
 
 header ethernet_t {
     mac_addr_t dst_addr;

p4src/static-mapping.p4

@@ -17,7 +17,17 @@ control MyIngress(inout headers hdr,
     inout standard_metadata_t standard_metadata) {
 
     /********************** ADDRESS TABLES ***********************************/
-    action icmp6_answer(port_t port) {
+    action icmp6_answer() {
+
+        if(hdr.icmp6.isValid()) {
+            if(hdr.icmp6.code == ICMP6_ECHO_REQUEST) {
+                ipv6_addr_t tmp = hdr.ipv6.src_addr;
+                hdr.ipv6.src_addr = hdr.ipv6.dst_addr;
+                hdr.ipv6.dst_addr = tmp;
+                hdr.icmp6.code = ICMP6_ECHO_REPLY;
+            }
+        }
+
         /* do something:
         - change src/dst
         - change type
@@ -27,6 +37,7 @@ control MyIngress(inout headers hdr,
     table v6_addresses {
         key = {
             hdr.ipv6.dst_addr: exact;
+//            hdr.ipv6.next_header: exact;
         }
         actions = {
 			icmp6_answer;