Sigcomm 17 (#52)

This problem contains the tutorial exercises and solutions presented at SIGCOMM '17.

SIGCOMM_2017/exercises/source_routing/source_routing.p4

@@ -0,0 +1,191 @@
+/* -*- P4_16 -*- */
+#include <core.p4>
+#include <v1model.p4>
+
+const bit<16> TYPE_IPV4 = 0x800;
+const bit<16> TYPE_SRCROUTING = 0x1234;
+
+#define MAX_HOPS 9
+
+/*************************************************************************
+*********************** H E A D E R S  ***********************************
+*************************************************************************/
+
+typedef bit<9>  egressSpec_t;
+typedef bit<48> macAddr_t;
+typedef bit<32> ip4Addr_t;
+
+header ethernet_t {
+    macAddr_t dstAddr;
+    macAddr_t srcAddr;
+    bit<16>   etherType;
+}
+
+header srcRoute_t {
+    bit<1>    bos;
+    bit<15>   port;
+}
+
+header ipv4_t {
+    bit<4>    version;
+    bit<4>    ihl;
+    bit<8>    diffserv;
+    bit<16>   totalLen;
+    bit<16>   identification;
+    bit<3>    flags;
+    bit<13>   fragOffset;
+    bit<8>    ttl;
+    bit<8>    protocol;
+    bit<16>   hdrChecksum;
+    ip4Addr_t srcAddr;
+    ip4Addr_t dstAddr;
+}
+
+struct metadata {
+    /* empty */
+}
+
+struct headers {
+    ethernet_t              ethernet;
+    srcRoute_t[MAX_HOPS]    srcRoutes;
+    ipv4_t                  ipv4;
+}
+
+/*************************************************************************
+*********************** P A R S E R  ***********************************
+*************************************************************************/
+
+parser MyParser(packet_in packet,
+                out headers hdr,
+                inout metadata meta,
+                inout standard_metadata_t standard_metadata) {
+
+    
+    state start {
+        transition parse_ethernet;
+    }
+
+    state parse_ethernet {
+        packet.extract(hdr.ethernet);
+        /*
+         * TODO: Modify the next line to select on hdr.ethernet.etherType
+         * If the value is TYPE_SRCROUTING transition to parse_srcRouting
+         * otherwise transition to accept.
+         */
+        transition accept;
+    }
+
+    state parse_srcRouting {
+        /*
+         * TODO: extract the next entry of hdr.srcRoutes
+         * while hdr.srcRoutes.last.bos is 0 transition to this state
+         * otherwise parse ipv4
+         */
+        transition accept;
+    }
+
+    state parse_ipv4 {
+        packet.extract(hdr.ipv4);
+        transition accept;
+    }
+
+}
+
+
+/*************************************************************************
+************   C H E C K S U M    V E R I F I C A T I O N   *************
+*************************************************************************/
+
+control MyVerifyChecksum(in headers hdr, inout metadata meta) {   
+    apply {  }
+}
+
+
+/*************************************************************************
+**************  I N G R E S S   P R O C E S S I N G   *******************
+*************************************************************************/
+
+control MyIngress(inout headers hdr,
+                  inout metadata meta,
+                  inout standard_metadata_t standard_metadata) {
+
+    action drop() {
+        mark_to_drop();
+    }
+    
+    action srcRoute_nhop() {
+        /*
+         * TODO: set standard_metadata.egress_spec 
+         * to the port in hdr.srcRoutes[0] and
+         * pop an entry from hdr.srcRoutes
+         */
+    }
+
+    action srcRoute_finish() {
+        hdr.ethernet.etherType = TYPE_IPV4;
+    }
+
+    action update_ttl(){
+        hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
+    }
+    
+    apply {
+        if (hdr.srcRoutes[0].isValid()){
+            /*
+             * TODO: add logic to:
+             * - If final srcRoutes (top of stack has bos==1):
+             *   - change etherType to IP
+             * - choose next hop and remove top of srcRoutes stack
+             */
+
+            if (hdr.ipv4.isValid()){
+                update_ttl();
+            }
+        }else{
+            drop();
+        } 
+    }
+}
+
+/*************************************************************************
+****************  E G R E S S   P R O C E S S I N G   *******************
+*************************************************************************/
+
+control MyEgress(inout headers hdr,
+                 inout metadata meta,
+                 inout standard_metadata_t standard_metadata) {
+    apply {  }
+}
+
+/*************************************************************************
+*************   C H E C K S U M    C O M P U T A T I O N   **************
+*************************************************************************/
+
+control MyComputeChecksum(inout headers hdr, inout metadata meta) {
+    apply {  }
+}
+
+/*************************************************************************
+***********************  D E P A R S E R  *******************************
+*************************************************************************/
+
+control MyDeparser(packet_out packet, in headers hdr) {
+    apply {
+        packet.emit(hdr.ethernet);
+        packet.emit(hdr.srcRoutes);
+        packet.emit(hdr.ipv4);
+    }
+}
+
+/*************************************************************************
+***********************  S W I T C H  *******************************
+*************************************************************************/
+
+V1Switch(
+MyParser(),
+MyVerifyChecksum(),
+MyIngress(),
+MyEgress(),
+MyComputeChecksum(),
+MyDeparser()
+) main;