From 66f71d33d516e2a7b16153173f55f9a251e6c553 Mon Sep 17 00:00:00 2001
From: agadiyar <aditya.gadiyar@intel.com>
Date: Thu, 13 Jun 2019 16:44:45 -0500
Subject: [PATCH] new example decrementTTL

---
 examples/.gitignore      |  1 +
 examples/Dockerfile      |  1 +
 examples/Makefile        |  3 ++-
 examples/decrementTTL.go | 40 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 examples/decrementTTL.go

diff --git a/examples/.gitignore b/examples/.gitignore
index f3341d52..eda6c703 100644
--- a/examples/.gitignore
+++ b/examples/.gitignore
@@ -14,3 +14,4 @@ devbind
 OSforwarding
 generate
 jumbo
+decrementTTL
diff --git a/examples/Dockerfile b/examples/Dockerfile
index 8a44e6da..4d612694 100644
--- a/examples/Dockerfile
+++ b/examples/Dockerfile
@@ -22,3 +22,4 @@ COPY netlink .
 COPY generate .
 COPY OSforwarding .
 COPY jumbo .
+COPY decrementTTL .
diff --git a/examples/Makefile b/examples/Makefile
index b41703ab..3aaaef21 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -7,7 +7,8 @@ IMAGENAME = nff-go-examples
 EXECUTABLES = dump clonablePcapDumper kni copy errorHandling timer \
 		createPacket sendFixedPktsNumber gtpu pingReplay \
 		netlink gopacketParserExample devbind generate \
-		OSforwarding jumbo
+		OSforwarding jumbo decrementTTL
+
 SUBDIRS = tutorial antiddos demo fileReadWrite firewall forwarding ipsec lb
 
 .PHONY: dpi nffPktgen
diff --git a/examples/decrementTTL.go b/examples/decrementTTL.go
new file mode 100644
index 00000000..cd2708a9
--- /dev/null
+++ b/examples/decrementTTL.go
@@ -0,0 +1,40 @@
+// Copyright 2017 Intel Corporation.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"flag"
+
+	"github.com/intel-go/nff-go/flow"
+	"github.com/intel-go/nff-go/packet"
+)
+
+// Main function for constructing packet processing graph.
+func main() {
+	inPort := flag.Uint("inPort", 0, "port for receiver")
+	outPort := flag.Uint("outPort", 1, "port for sender")
+	flag.Parse()
+
+	flow.SystemInit(nil)
+	inputFlow, _ := flow.SetReceiver(uint16(*inPort))
+	flow.SetHandlerDrop(inputFlow, decrementTTL, nil)
+	flow.SetSender(inputFlow, uint16(*outPort))
+	flow.SystemStart()
+}
+
+func decrementTTL(current *packet.Packet, c flow.UserContext) bool {
+	current.ParseL3() // must parse before header can be read
+	header := current.GetIPv4()
+	if header == nil { // not IPv4
+		return false
+	}
+
+	header.TimeToLive--
+	if header.TimeToLive == 0 { // TTL exceeded, drop
+		return false
+	} else {
+		return true
+	}
+}