TUN-6666: Define packet package

This package defines IP and ICMP packet, decoders, encoder and flow

vendor/github.com/google/gopacket/layers/fuzz_layer.go

@@ -0,0 +1,39 @@
+// Copyright 2019 The GoPacket Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found
+// in the LICENSE file in the root of the source tree.
+
+package layers
+
+import (
+	"encoding/binary"
+
+	"github.com/google/gopacket"
+)
+
+// FuzzLayer is a fuzz target for the layers package of gopacket
+// A fuzz target is a function processing a binary blob (byte slice)
+// The process here is to interpret this data as a packet, and print the layers contents.
+// The decoding options and the starting layer are encoded in the first bytes.
+// The function returns 1 if this is a valid packet (no error layer)
+func FuzzLayer(data []byte) int {
+	if len(data) < 3 {
+		return 0
+	}
+	// use the first two bytes to choose the top level layer
+	startLayer := binary.BigEndian.Uint16(data[:2])
+	var fuzzOpts = gopacket.DecodeOptions{
+		Lazy:                     data[2]&0x1 != 0,
+		NoCopy:                   data[2]&0x2 != 0,
+		SkipDecodeRecovery:       data[2]&0x4 != 0,
+		DecodeStreamsAsDatagrams: data[2]&0x8 != 0,
+	}
+	p := gopacket.NewPacket(data[3:], gopacket.LayerType(startLayer), fuzzOpts)
+	for _, l := range p.Layers() {
+		gopacket.LayerString(l)
+	}
+	if p.ErrorLayer() != nil {
+		return 0
+	}
+	return 1
+}