Starting data structures

.gitignore

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+
+# Created by https://www.toptal.com/developers/gitignore/api/intellij+all,go
+# Edit at https://www.toptal.com/developers/gitignore?templates=intellij+all,go
+
+### Go ###
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+### Go Patch ###
+/vendor/
+/Godeps/
+
+### Intellij+all ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### Intellij+all Patch ###
+# Ignores the whole .idea folder and all .iml files
+# See https://github.com/joeblau/gitignore.io/issues/186 and https://github.com/joeblau/gitignore.io/issues/360
+
+.idea/
+
+# Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-249601023
+
+*.iml
+modules.xml
+.idea/misc.xml
+*.ipr
+
+# Sonarlint plugin
+.idea/sonarlint
+
+# End of https://www.toptal.com/developers/gitignore/api/intellij+all,go

go.mod

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+module mbpl3p
+
+go 1.15
+
+require golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897

go.sum

@@ -0,0 +1,8 @@
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897 h1:pLI5jrR7OSLijeIDcmRxNmw2api+jEfxLoykJVice/E=
+golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

main.go

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+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("hello world")
+}

proxy/packet.go

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+package proxy
+
+import (
+	"encoding/binary"
+	"time"
+)
+
+type Packet struct {
+	Data      []byte
+	timestamp time.Time
+}
+
+func NewPacket(data []byte) Packet {
+	return Packet{
+		Data: data,
+		timestamp: time.Now(),
+	}
+}
+
+func UnmarshalPacket(raw []byte, verifier MacVerifier) *Packet {
+	// the MAC is the last N bytes
+	data := raw[:len(raw)-verifier.CodeLength()]
+	sum := raw[len(raw)-verifier.CodeLength():]
+
+	if !verifier.Verify(data, sum) {
+		return nil
+	}
+
+	p := Packet{
+		Data: data[:8],
+	}
+
+	unixTime := int64(binary.LittleEndian.Uint64(data[len(data)-8:]))
+	p.timestamp = time.Unix(unixTime, 0)
+
+	return &p
+}
+
+func (p Packet) Marshal(generator MacGenerator) []byte {
+	// length of data + length of timestamp (8 byte) + length of checksum
+	slice := make([]byte, len(p.Data)+8+generator.CodeLength())
+
+	copy(slice, p.Data)
+
+	unixTime := uint64(p.timestamp.Unix())
+	binary.LittleEndian.PutUint64(slice[len(p.Data):], unixTime)
+
+	mac := generator.Generate(slice)
+	copy(slice[len(p.Data)+8:], mac)
+
+	return slice
+}

proxy/proxy.go

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+package proxy
+
+const ChecksumLength = 16
+
+type Producer interface {
+	IsAlive() bool
+	Produce(chan Packet)
+}
+
+type Consumer interface {
+	IsAlive() bool
+	Consume(chan Packet)
+}
+
+type MacGenerator interface {
+	CodeLength() int
+	Generate([]byte) []byte
+}
+
+type MacVerifier interface {
+	CodeLength() int
+	Verify(data []byte, sum []byte) bool
+}
+
+type Source interface {
+}
+
+type Sink interface {
+	Release(packet Packet)
+}
+
+type Proxy struct {
+	proxyChan chan Packet
+	sinkChan  chan Packet
+}