🏷️ Version 1.0.0

**Added**:
* `Search` will return the manufacturer of the given MAC address.

.github/workflows/go-test.yml

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+name: Go Test
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.19
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Test
+        run: go test -v ./...

README.md

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+# gomanuf
+
+[![Go Reference](https://pkg.go.dev/badge/github.com/kkrypt0nn/gomanuf.svg)](https://pkg.go.dev/github.com/kkrypt0nn/gomanuf) ![Repository License](https://img.shields.io/github/license/kkrypt0nn/gomanuf?style=flat-square) ![Code Size](https://img.shields.io/github/languages/code-size/kkrypt0nn/gomanuf?style=flat-square) ![Last Commit](https://img.shields.io/github/last-commit/kkrypt0nn/gomanuf?style=flat-square)
+
+`gomanuf` is a very simple library used for [Project Absence](https://github.com/ProjectAbsence) to get the manufacturer of a specific MAC address.
+
+## Installation
+If you want to use this library for one of your projects, you can install it like any other Go library
+
+```shell
+go get github.com/kkrypt0nn/gomanuf
+```
+
+## Example
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/kkrypt0nn/gomanuf"
+)
+
+func main() {
+	manuf, _ := gomanuf.Search("C4:A8:1D:73:D7:8C")
+	fmt.Println(manuf)
+}
+
+```
+
+## License
+This library was made with 💜 by Krypton and is under the [GPL v3](LICENSE.md) license.

example/main.go

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+package main
+
+import (
+	"fmt"
+	"github.com/kkrypt0nn/gomanuf"
+)
+
+func main() {
+	manuf, _ := gomanuf.Search("C4:A8:1D:73:D7:8C")
+	fmt.Println(manuf)
+}

go.mod

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+module github.com/kkrypt0nn/gomanuf
+
+go 1.19

gomanuf.go

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+package gomanuf
+
+import (
+	"fmt"
+	"os"
+	"regexp"
+	"strings"
+)
+
+var data map[string]string
+var slash28 map[string]string
+var slash36 map[string]string
+
+var macRegex, _ = regexp.Compile("^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$")
+
+func init() {
+	data = make(map[string]string)
+	slash28 = make(map[string]string)
+	slash36 = make(map[string]string)
+	file, err := os.ReadFile("manuf.txt")
+	if err != nil {
+		panic(err)
+	}
+	lines := strings.Split(string(file), "\n")
+	for i := 0; i < len(lines); i++ {
+		line := lines[i]
+		fields := strings.Split(line, "\t")
+
+		// Ignore the comments and empty lines
+		if strings.HasPrefix(fields[0], "#") || line == "" {
+			continue
+		}
+
+		mac := fields[0]
+		manuf := fields[1]
+		if len(fields) > 2 {
+			manuf = fields[2]
+		}
+		if strings.Contains(mac, ":00/28") {
+			slash28[mac] = manuf
+		} else if strings.Contains(mac, ":00/36") {
+			slash36[mac] = manuf
+		}
+
+		data[mac] = manuf
+	}
+}
+
+func checkSlash28(mac string) string {
+	mac = mac[:10] + "0:00:00/28"
+	for address, manuf := range slash28 {
+		if address == mac {
+			return manuf
+		}
+	}
+	return ""
+}
+
+func checkSlash36(mac string) string {
+	mac = mac[:13] + "0:00/36"
+	for address, manuf := range slash36 {
+		if address == mac {
+			return manuf
+		}
+	}
+	return ""
+}
+
+// Search will return the manufacturer of the given MAC address.
+func Search(mac string) (string, error) {
+	mac = strings.Replace(strings.ToUpper(mac), "-", ":", -1)
+	if !macRegex.MatchString(mac) {
+		return "Invalid MAC address", fmt.Errorf("invalid MAC address")
+	}
+	for address, manuf := range data {
+		if strings.HasPrefix(mac, address) {
+			// Check if manufacturer is one of those manufacturer that have MACs with /28 or /36
+			if manuf == "IEEE Registration Authority" {
+				check28 := checkSlash28(mac)
+				if check28 != "" {
+					return check28, nil
+				}
+				check36 := checkSlash36(mac)
+				if check36 != "" {
+					return check36, nil
+				}
+			}
+
+			return manuf, nil
+		}
+	}
+	return "unknown", nil
+}

gomanuf_test.go

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+package gomanuf
+
+import "testing"
+
+func TestDLink(t *testing.T) {
+	manuf, _ := Search("C4:A8:1D:73:D7:8C")
+	if manuf == "D-Link International" {
+		t.Log("D-Link International MAC address found.")
+		return
+	}
+	t.Errorf("Found %s instead of D-Link International!", manuf)
+}
+
+func TestNetgear(t *testing.T) {
+	manuf, _ := Search("9C:D3:6D:9A:CA:81")
+	if manuf == "Netgear" {
+		t.Log("Netgear MAC address found.")
+		return
+	}
+	t.Errorf("Found %s instead of Netgear!", manuf)
+}
+
+func TestShanghaiBroadwanCommunications(t *testing.T) {
+	manuf, _ := Search("40:ED:98:6F:DB:AC")
+	if manuf == "Shanghai Broadwan Communications Co.,Ltd" {
+		t.Log("Shanghai Broadwan Communications Co.,Ltd MAC address found.")
+		return
+	}
+	t.Errorf("Found %s instead of Shanghai Broadwan Communications Co.,Ltd!", manuf)
+}
+
+func TestPiranhaEMS(t *testing.T) {
+	manuf, _ := Search("70:B3:D5:8C:CD:BE")
+	if manuf == "Piranha EMS Inc." {
+		t.Log("Piranha EMS Inc. MAC address found.")
+		return
+	}
+	t.Errorf("Found %s instead of Piranha EMS Inc.!", manuf)
+}
+
+func TestIEEERegistrationAuthority(t *testing.T) {
+	manuf, _ := Search("3C:24:F0:F0:BE:CF")
+	if manuf == "IEEE Registration Authority" {
+		t.Log("IEEE Registration Authority MAC address found.")
+		return
+	}
+	t.Errorf("Found %s instead of IEEE Registration Authority!", manuf)
+}
+
+func TestSamsungElectronics(t *testing.T) {
+	manuf, _ := Search("24:FC:E5:AD:BB:89")
+	if manuf == "Samsung Electronics Co.,Ltd" {
+		t.Log("Samsung Electronics Co.,Ltd MAC address found.")
+		return
+	}
+	t.Errorf("Found %s instead of Samsung Electronics Co.,Ltd!", manuf)
+}
+
+func TestInvalidAddress(t *testing.T) {
+	manuf, _ := Search("G4:FC:E5:AD:BB:89")
+	if manuf == "Invalid MAC address" {
+		t.Log("Invalid MAC address MAC address found.")
+		return
+	}
+	t.Errorf("Found %s instead of Invalid MAC address!", manuf)
+}