Add Heavy Hitter to examples master (#10)

Add Heavy Hitter to SIGCOMM 2016 in master

SIGCOMM_2016/heavy_hitter/p4src/heavy_hitter_template.p4

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+/* Copyright 2013-present Barefoot Networks, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "includes/headers.p4"
+#include "includes/parser.p4"
+
+// TODO: Define the threshold value
+
+field_list ipv4_checksum_list {
+        ipv4.version;
+        ipv4.ihl;
+        ipv4.diffserv;
+        ipv4.totalLen;
+        ipv4.identification;
+        ipv4.flags;
+        ipv4.fragOffset;
+        ipv4.ttl;
+        ipv4.protocol;
+        ipv4.srcAddr;
+        ipv4.dstAddr;
+}
+
+field_list_calculation ipv4_checksum {
+    input {
+        ipv4_checksum_list;
+    }
+    algorithm : csum16;
+    output_width : 16;
+}
+
+calculated_field ipv4.hdrChecksum  {
+    verify ipv4_checksum;
+    update ipv4_checksum;
+}
+
+action _drop() {
+    drop();
+}
+
+header_type custom_metadata_t {
+    fields {
+        nhop_ipv4: 32;
+        // TODO: Add the metadata for hash indices and count values
+    }
+}
+
+metadata custom_metadata_t custom_metadata;
+
+action set_nhop(nhop_ipv4, port) {
+    modify_field(custom_metadata.nhop_ipv4, nhop_ipv4);
+    modify_field(standard_metadata.egress_spec, port);
+    add_to_field(ipv4.ttl, -1);
+}
+
+action set_dmac(dmac) {
+    modify_field(ethernet.dstAddr, dmac);
+}
+
+// TODO: Define the field list to compute the hash on
+// Use the 5 tuple of 
+// (src ip, dst ip, src port, dst port, ip protocol)
+
+// TODO: Define two different hash functions to store the counts
+// Note: Please use csum16 and crc16 for the hash functions
+
+// TODO: Define the registers to store the counts
+
+
+// TODO: Actions to set heavy hitter filter
+
+
+// TODO: Define the tables to run actions
+
+
+// TODO: Define table to drop the heavy hitter traffic
+
+
+table ipv4_lpm {
+    reads {
+        ipv4.dstAddr : lpm;
+    }
+    actions {
+        set_nhop;
+        _drop;
+    }
+    size: 1024;
+}
+
+table forward {
+    reads {
+        custom_metadata.nhop_ipv4 : exact;
+    }
+    actions {
+        set_dmac;
+        _drop;
+    }
+    size: 512;
+}
+
+action rewrite_mac(smac) {
+    modify_field(ethernet.srcAddr, smac);
+}
+
+table send_frame {
+    reads {
+        standard_metadata.egress_port: exact;
+    }
+    actions {
+        rewrite_mac;
+        _drop;
+    }
+    size: 256;
+}
+
+control ingress {
+    // TODO: Add table control here
+    if (// TODO: Add conditional here) {
+        // TODO: apply table here
+    } else {
+        apply(ipv4_lpm);
+        apply(forward);
+    }
+}
+
+control egress {
+    apply(send_frame);
+}