Create a early first working version

go.mod

@@ -0,0 +1,15 @@
+module github.com/themimitoof/ipg
+
+go 1.18
+
+require (
+	github.com/alecthomas/kong v0.6.1
+	github.com/c-robinson/iplib v1.0.3
+	github.com/fatih/color v1.13.0
+)
+
+require (
+	github.com/mattn/go-colorable v0.1.9 // indirect
+	github.com/mattn/go-isatty v0.0.14 // indirect
+	golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c // indirect
+)

go.sum

@@ -0,0 +1,28 @@
+github.com/alecthomas/kong v0.6.1 h1:1kNhcFepkR+HmasQpbiKDLylIL8yh5B5y1zPp5bJimA=
+github.com/alecthomas/kong v0.6.1/go.mod h1:JfHWDzLmbh/puW6I3V7uWenoh56YNVONW+w8eKeUr9I=
+github.com/alecthomas/repr v0.0.0-20210801044451-80ca428c5142 h1:8Uy0oSf5co/NZXje7U1z8Mpep++QJOldL2hs/sBQf48=
+github.com/alecthomas/repr v0.0.0-20210801044451-80ca428c5142/go.mod h1:2kn6fqh/zIyPLmm3ugklbEi5hg5wS435eygvNfaDQL8=
+github.com/c-robinson/iplib v1.0.3 h1:NG0UF0GoEsrC1/vyfX1Lx2Ss7CySWl3KqqXh3q4DdPU=
+github.com/c-robinson/iplib v1.0.3/go.mod h1:i3LuuFL1hRT5gFpBRnEydzw8R6yhGkF4szNDIbF8pgo=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fatih/color v1.13.0 h1:8LOYc1KYPPmyKMuN8QV2DNRWNbLo6LZ0iLs8+mlH53w=
+github.com/fatih/color v1.13.0/go.mod h1:kLAiJbzzSOZDVNGyDpeOxJ47H46qBXwg5ILebYFFOfk=
+github.com/mattn/go-colorable v0.1.9 h1:sqDoxXbdeALODt0DAeJCVp38ps9ZogZEAXjus69YV3U=
+github.com/mattn/go-colorable v0.1.9/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc=
+github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
+github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
+github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.2 h1:4jaiDzPyXQvSd7D0EjG45355tLlV3VOECpq10pLC+8s=
+github.com/stretchr/testify v1.7.2/go.mod h1:R6va5+xMeoiuVRoj+gSkQ7d3FALtqAAGI1FQKckRals=
+golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c h1:F1jZWGFhYfh0Ci55sIpILtKKK8p3i2/krTr0H1rg74I=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

ipg.go

@@ -0,0 +1,176 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"net"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/alecthomas/kong"
+	"github.com/c-robinson/iplib"
+	"github.com/fatih/color"
+)
+
+var cli struct {
+	Subnet        string `arg:"" help:"IPv6 Subnet"`
+	Random        bool   `short:"r" xor:"Name,Random" required:"" help:"Generate a random IPv6 address on the given subnet."`
+	Name          string `short:"n" xor:"Name,Random" required:"" help:"Specify the hostname of a machine, an IPv6 address will be generated based on it."`
+	Silent        bool   `short:"s" help:"Only display values without their labels."`
+	Reverse       bool   `short:"R" help:"Display the ARPA version of the IP address."`
+	DNSRecord     bool   `name:"dns" short:"d" help:"Returns a DNS record ready to paste to a DNS zone."`
+	ReverseRecord bool   `name:"rrecord" short:"x" help:"Returns a rDNS record ready to paste to a DNS zone."`
+	DNSTTL        int    `name:"ttl" short:"t" default:"86400" help:"TTL value for DNS returned DNS records."`
+}
+
+// Function stollen from c-robinson/iplib, method non-exposed by the lib ¯\_(ツ)_/¯
+func Net6wildcard(n iplib.Net6) net.IPMask {
+	wc := make([]byte, len(n.Mask()))
+	for i, b := range n.Mask() {
+		wc[i] = 0xff - b
+	}
+	return wc
+}
+
+func RandomNumber(min int, max int) int {
+	rand.Seed(time.Now().UnixNano())
+	return rand.Intn(max-min) + min
+}
+
+// Generate a random IP address based on the given IP subnet.
+func GenerateRandomIP(net iplib.Net6) net.IP {
+	finalIP := net.FirstAddress()
+
+	for idx, b := range net.Mask() {
+		if b == 0xff {
+			continue
+		} else if b != 0x0 {
+			randByte := byte(RandomNumber(0, 255))
+			wildCardByte := Net6wildcard(net)[idx]
+
+			finalIP[idx] = net.IP()[idx] + wildCardByte&randByte
+		} else {
+			finalIP[idx] = byte(RandomNumber(0, 255))
+		}
+	}
+
+	return finalIP
+}
+
+// Generate an IP address based on the hostname.
+// The algorithm first tries with the complete hostname, if it does not work,
+// it tries by removing vowels and iterate by removing character by character.
+func GenerateIPFromHostname(net iplib.Net6, hostname string) net.IP {
+	finalIP := []byte(net.FirstAddress())
+	cidr, _ := net.Mask().Size()
+	availableBits := 128 - cidr
+	hostname = strings.Split(hostname, ".")[0]
+
+	if len(hostname)*8 > availableBits {
+		// Remove vowels
+		shrinkedHostname := []byte{}
+		for _, c := range hostname {
+			asVowel := false
+
+			for _, v := range "aiueo" {
+				if c == v {
+					asVowel = true
+				}
+			}
+
+			if !asVowel {
+				shrinkedHostname = append(shrinkedHostname, byte(c))
+			}
+		}
+
+		// In case it's not enough, shrink last character until it fits
+		for len(shrinkedHostname)*8 > availableBits {
+			shrinkedHostname = shrinkedHostname[0 : len(shrinkedHostname)-1]
+		}
+
+		hostname = string(shrinkedHostname)
+	}
+
+	for i, c := range hostname {
+		pos := len(finalIP) - len(hostname) + i
+		finalIP[pos] = byte(c)
+	}
+
+	return finalIP
+}
+
+// Generate a DNS record ready to be paste on a Bind compatible zone
+func GenerateDNSRecord(ip string, ttl int, hostname string) string {
+	return fmt.Sprintf("%s\t%d\tIN\tAAAA\t%s", hostname, ttl, ip)
+}
+
+// Generate a ARPA record ready to be paste on a Bind compatible zone
+func GenerateReverseDNSRecord(ip string, ttl int, hostname string) string {
+	return fmt.Sprintf("%s.\t%d\tIN\tPTR\t%s", ip, ttl, hostname)
+}
+
+func main() {
+	kong.Parse(
+		&cli,
+		kong.Description("A simple IPv6 generator for lazy netadmins."),
+	)
+
+	var ipNetwork iplib.Net6 = iplib.Net6FromStr(cli.Subnet)
+
+	// Check if the Subnet is valid or not.
+	if len(ipNetwork.IP()) == 0 {
+		fmt.Println("The given subnet is not valid.")
+		os.Exit(1)
+	}
+
+	// Check if the subnet is not too small to be used
+	var cidr, _ = ipNetwork.Mask().Size()
+
+	if cidr > 126 {
+		fmt.Printf("The given subnet is too small (/%d) to be used with ipg.\n", cidr)
+		os.Exit(1)
+	}
+
+	// Generate the new IP address using the given generation method
+	var generatedIp net.IP
+
+	if cli.Random {
+		generatedIp = GenerateRandomIP(ipNetwork)
+	} else {
+		generatedIp = GenerateIPFromHostname(ipNetwork, cli.Name)
+	}
+
+	var reverseIpAddr string = iplib.IPToARPA(generatedIp)
+	var ipAddr string = generatedIp.String()
+
+	// Always display the generated IP address
+	if !cli.Silent {
+		fmt.Printf("IP address: ")
+	}
+	color.Yellow(ipAddr)
+
+	// Display the ARPA version of the IP address if the flag is set
+	if cli.Reverse {
+		if !cli.Silent {
+			fmt.Printf("Reverse IP address: ")
+		}
+		color.Yellow(reverseIpAddr)
+	}
+
+	// Display the BIND DNS record if the flag is set
+	if cli.DNSRecord {
+		if !cli.Silent {
+			fmt.Println("DNS record:")
+		}
+		color.Yellow(GenerateDNSRecord(ipAddr, cli.DNSTTL, cli.Name))
+	}
+
+	// Display the ARPA DNS record if the flag is set
+	if cli.ReverseRecord {
+		if !cli.Silent {
+			fmt.Println("ARPA DNS record:")
+		}
+		color.Yellow(GenerateReverseDNSRecord(reverseIpAddr, cli.DNSTTL, cli.Name))
+	}
+}