Added guide to add table entries in P4 dpdk using native control plan…

doc/P4-DPDK-starting-guide/mac_modifier.p4

@@ -0,0 +1,190 @@
+/* -*- P4_16 -*- */
+#include <core.p4>
+#include <dpdk/psa.p4>
+
+typedef bit<48> MacAddr;
+typedef bit<32> IPv4Addr;
+typedef bit<16> PortId_t;
+
+// Headers
+header ethernet_t {
+    MacAddr dstAddr;
+    MacAddr srcAddr;
+    bit<16> etherType;
+}
+
+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;
+    IPv4Addr  srcAddr;
+    IPv4Addr  dstAddr;
+}
+
+// Parser and struct definitions
+struct headers_t {
+    ethernet_t ethernet;
+    ipv4_t     ipv4;
+}
+
+struct metadata_t {
+    // Empty for now
+}
+
+// Parser
+parser IngressParserImpl(
+    packet_in buffer,
+    out headers_t headers,
+    inout metadata_t meta,
+    in psa_ingress_parser_input_t istd,
+    in empty_t resubmit_meta,
+    in empty_t recirculate_meta) {
+
+    state start {
+        buffer.extract(headers.ethernet);
+        transition select(headers.ethernet.etherType) {
+            0x0800: parse_ipv4;
+            default: accept;
+        }
+    }
+
+    state parse_ipv4 {
+        buffer.extract(headers.ipv4);
+        transition accept;
+    }
+}
+
+parser EgressParserImpl(
+    packet_in buffer,
+    out headers_t headers,
+    inout metadata_t meta,
+    in psa_egress_parser_input_t istd,
+    in empty_t normal_meta,
+    in empty_t clone_i2e_meta,
+    in empty_t clone_e2e_meta) {
+
+    state start {
+        buffer.extract(headers.ethernet);
+        transition select(headers.ethernet.etherType) {
+            0x0800: parse_ipv4;
+            default: accept;
+        }
+    }
+
+    state parse_ipv4 {
+        buffer.extract(headers.ipv4);
+        transition accept;
+    }
+}
+
+// Main control block
+control IngressImpl(
+    inout headers_t headers,
+    inout metadata_t meta,
+    in    psa_ingress_input_t  istd,
+    inout psa_ingress_output_t ostd) {
+
+    // Action to modify source MAC
+    action modify_src_mac(MacAddr new_src_mac) {
+        headers.ethernet.srcAddr = new_src_mac;
+    }
+
+    // Action to modify destination MAC
+    action modify_dst_mac(MacAddr new_dst_mac) {
+        headers.ethernet.dstAddr = new_dst_mac;
+    }
+
+    // Exact match table for source MAC modification
+    table exact_match_table {
+        key = {
+            headers.ethernet.dstAddr: exact;
+            headers.ethernet.srcAddr: exact;
+            headers.ipv4.protocol: exact;
+        }
+        actions = {
+            modify_src_mac;
+            NoAction;
+        }
+        default_action = NoAction();
+        size = 1024;
+    }
+
+    // Ternary match table for destination MAC modification
+    table ternary_match_table {
+        key = {
+            headers.ipv4.srcAddr: ternary;
+            headers.ipv4.dstAddr: ternary;
+            headers.ipv4.protocol: ternary;
+        }
+        actions = {
+            modify_dst_mac;
+            NoAction;
+        }
+        default_action = NoAction();
+        size = 1024;
+    }
+
+    apply {
+        if (headers.ipv4.isValid()) {
+            exact_match_table.apply();
+            ternary_match_table.apply();
+        }
+
+        // Send out packet on the same port it came in
+        send_to_port(ostd, (PortId_t)istd.ingress_port);
+    }
+}
+
+control EgressImpl(
+    inout headers_t headers,
+    inout metadata_t meta,
+    in    psa_egress_input_t  istd,
+    inout psa_egress_output_t ostd) {
+    apply { }
+}
+
+// Deparser
+control IngressDeparserImpl(
+    packet_out packet,
+    out empty_t clone_i2e_meta,
+    out empty_t resubmit_meta,
+    out empty_t normal_meta,
+    inout headers_t headers,
+    in metadata_t meta,
+    in psa_ingress_output_t istd) {
+    apply {
+        packet.emit(headers.ethernet);
+        packet.emit(headers.ipv4);
+    }
+}
+
+control EgressDeparserImpl(
+    packet_out packet,
+    out empty_t clone_e2e_meta,
+    out empty_t recirculate_meta,
+    inout headers_t headers,
+    in metadata_t meta,
+    in psa_egress_output_t istd,
+    in psa_egress_deparser_input_t edstd) {
+    apply {
+        packet.emit(headers.ethernet);
+        packet.emit(headers.ipv4);
+    }
+}
+
+// Instantiate the PSA switch
+IngressParserImpl() ip;
+IngressImpl() ingress;
+IngressDeparserImpl() id;
+EgressParserImpl() ep;
+EgressImpl() egress;
+EgressDeparserImpl() ed;
+
+PSA_Switch(ip, ingress, id, ep, egress, ed) main;