Merge pull request #4 from johnjaylward/support_dual_stack

Support dual stack IPv4 and IPv6

README.md

@@ -1,7 +1,7 @@
 # DIGITAL OCEAN DYNAMIC IP API CLIENT
 A simple script in Go language to automatically update Digital ocean DNS records if you have a dynamic IP. Since it can be compiled on any platform, you can use it along with raspberrypi etc.
 
-To find your Dynamic IP, this program will call out to https://diagnostic.opendns.com/myip.
+To find your Dynamic IP, this program will call out to https://ipv4bot.whatismyipaddress.com for ipv4 addresses and https://ipv6bot.whatismyipaddress.com for ipv6 addresses. This is to support dual-stack environments.
 
 ## requirements
 Requires Git and Go for building.
@@ -21,6 +21,9 @@ create a file ".digitalocean-dynamic-ip.json"(dot prefix to hide the file) and p
 {
   "apikey": "samplekeydasjkdhaskjdhrwofihsamplekey",
   "doPageSize" : 20,
+  "useIPv4": true,
+  "useIPv6": false,
+  "allowIPv4InIPv6": false,
   "domains": [
     {
       "domain": "example.com",
@@ -46,7 +49,11 @@ create a file ".digitalocean-dynamic-ip.json"(dot prefix to hide the file) and p
 ```
 The TTL can optionally be updated if passed in the configuration. Digital Ocean has a minimum TTL of 30 seconds. The `type` and the `name` must match existing records in the Digital Ocean DNS configuration. Only `types` of `A` and `AAAA` allowed at the moment.
 
-If you want to reduce the number of calls made to the digital ocean API and have more than 20 DNS records in your domain, you can adjust the `doPageSize` parameter. By default, Digital Ocean returns 20 records per page.
+If you want to reduce the number of calls made to the digital ocean API and have more than 20 DNS records in your domain, you can adjust the `doPageSize` parameter. By default, Digital Ocean returns 20 records per page. Digital Ocean has a max page size of 200 items.
+
+By default, the configuration checks both IPv4 and IPv6 addresses assuming your provider set up your connection as dual stack. If you know you only have ipv4 or ipv6 you can disable using one or the other in the config. To disable one or the other, set the `useIPv4` or `useIPv6` settings to `false`. If the options aren't present, or are set to `null`, then the configuration assumes a value of `true`.
+
+The `allowIPv4InIPv6` configuration option will allow adding an IPv4 address to be used in a AAAA record for IPv6 lookups.
 
 ```bash
 #run

digitalocean-dynamic-ip.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/hex"
 	"encoding/json"
 	"flag"
 	"fmt"
@@ -26,9 +27,12 @@ var config ClientConfig
 
 // ClientConfig : configuration json
 type ClientConfig struct {
-	APIKey     string   `json:"apiKey"`
+	APIKey          string   `json:"apiKey"`
-	DOPageSize int      `json:"doPageSize"`
+	DOPageSize      int      `json:"doPageSize"`
-	Domains    []Domain `json:"domains"`
+	UseIPv4         *bool    `json:"useIPv4"`
+	UseIPv6         *bool    `json:"useIPv6"`
+	AllowIPv4InIPv6 bool     `json:"allowIPv4InIPv6"`
+	Domains         []Domain `json:"domains"`
 }
 
 // Domain : domains to be changed
@@ -111,14 +115,49 @@ func usage() {
 	))
 }
 
-//CheckLocalIP : get current IP of server.
+//CheckLocalIPs : get current IP of server. checks both IPv4 and Ipv6 to support dual stack environments
-func CheckLocalIP() string {
+func CheckLocalIPs() (ipv4, ipv6 net.IP) {
-	currentIPRequest, err := http.Get("https://diagnostic.opendns.com/myip")
+	var ipv4String, ipv6String string
+
+	if config.UseIPv4 == nil || *(config.UseIPv4) {
+		ipv4String, _ = getURLBody("https://ipv4bot.whatismyipaddress.com")
+		if ipv4String == "" {
+			log.Println("No IPv4 address found. Consider disabling IPv4 checks in the config `\"useIPv4\": false`")
+		} else {
+			ipv4 = net.ParseIP(ipv4String)
+			if ipv4 != nil {
+				// make sure we got back an actual ipv4 address
+				ipv4 = ipv4.To4()
+			}
+			if ipv4 == nil {
+				log.Printf("Unable to parse `%s` as an IPv4 address", ipv4String)
+			}
+		}
+	}
+
+	if config.UseIPv6 == nil || *(config.UseIPv6) {
+		ipv6String, _ = getURLBody("https://ipv6bot.whatismyipaddress.com")
+		if ipv6String == "" {
+			log.Println("No IPv6 address found. Consider disabling IPv6 checks in the config `\"useIPv6\": false`")
+		} else {
+			ipv6 = net.ParseIP(ipv6String)
+			if ipv6 == nil {
+				log.Printf("Unable to parse `%s` as an IPv6 address", ipv6String)
+			}
+		}
+	}
+	return ipv4, ipv6
+}
+
+func getURLBody(url string) (string, error) {
+	request, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+	defer request.Body.Close()
+	body, err := ioutil.ReadAll(request.Body)
 	checkError(err)
-	defer currentIPRequest.Body.Close()
+	return string(body), nil
-	currentIPRequestParse, err := ioutil.ReadAll(currentIPRequest.Body)
-	checkError(err)
-	return string(currentIPRequestParse)
 }
 
 //GetDomainRecords : Get DNS records of current domain.
@@ -128,7 +167,12 @@ func GetDomainRecords(domain string) []DNSRecord {
 	pageParam := ""
 	// 20 is the default page size
 	if config.DOPageSize > 0 && config.DOPageSize != 20 {
-		pageParam = "?per_page=" + strconv.Itoa(config.DOPageSize)
+		pageSize := config.DOPageSize
+		// don't let users set more than the max size
+		if pageSize > 200 {
+			pageSize = 200
+		}
+		pageParam = "?per_page=" + strconv.Itoa(pageSize)
 	}
 	for url := "https://api.digitalocean.com/v2/domains/" + url.PathEscape(domain) + "/records" + pageParam; url != ""; url = page.Links.Pages.Next {
 		page = getPage(url)
@@ -148,7 +192,7 @@ func getPage(url string) DOResponse {
 	checkError(err)
 	defer response.Body.Close()
 	body, err := ioutil.ReadAll(response.Body)
-	// log.Print(string(body))
+	// log.Println(string(body))
 	var jsonDOResponse DOResponse
 	e := json.Unmarshal(body, &jsonDOResponse)
 	checkError(e)
@@ -156,46 +200,63 @@ func getPage(url string) DOResponse {
 }
 
 // UpdateRecords : Update DNS records of domain
-func UpdateRecords(domain string, ip net.IP, toUpdateRecords []DNSRecord) {
+func UpdateRecords(domain Domain, ipv4, ipv6 net.IP) {
-	currentIP := ip.String()
+	log.Printf("%s: %d to update", domain.Domain, len(domain.Records))
-	isIpv6 := ip.To4() == nil
-	if !isIpv6 {
-		// make sure we are using a v4 format
-		currentIP = ip.To4().String()
-	}
-	log.Printf("%s: %d to update\n", domain, len(toUpdateRecords))
 	updated := 0
-	doRecords := GetDomainRecords(domain)
+	doRecords := GetDomainRecords(domain.Domain)
 	// look for the item to update
 	if len(doRecords) < 1 {
-		log.Printf("%s: No DNS records found", domain)
+		log.Printf("%s: No DNS records found in Digital Ocean", domain.Domain)
 		return
 	}
-	log.Printf("%s: %d DNS records found", domain, len(doRecords))
+	log.Printf("%s: %d DNS records found in Digital Ocean", domain.Domain, len(doRecords))
-	for _, toUpdateRecord := range toUpdateRecords {
+	for _, toUpdateRecord := range domain.Records {
 		if toUpdateRecord.Type != "A" && toUpdateRecord.Type != "AAAA" {
-			log.Fatalf("%s: Unsupported type (Only A and AAAA records supported) for updates %+v", domain, toUpdateRecord)
+			log.Printf("%s: Unsupported type (Only A and AAAA records supported) for updates %+v", domain.Domain, toUpdateRecord)
+			continue
 		}
-		if isIpv6 && toUpdateRecord.Type == "A" {
+		if ipv4 == nil && toUpdateRecord.Type == "A" {
-			log.Fatalf("%s: You are trying to update an IPV4 A record with an IPV6 address: new ip: %s, config: %+v", domain, currentIP, toUpdateRecord)
+			log.Printf("%s: You are trying to update an IPv4 A record with no IPv4 address: config: %+v", domain.Domain, toUpdateRecord)
-		}
+			continue
-		if !isIpv6 && toUpdateRecord.Type == "AAAA" {
-			log.Fatalf("%s: You are trying to update an IPV6 A record with an IPV4 address: new ip: %s, config: %+v", domain, currentIP, toUpdateRecord)
 		}
 		if toUpdateRecord.ID > 0 {
 			// update the record directly. skip the extra search
-			log.Fatalf("%s: Unable to directly update records yet. Record: %+v", domain, toUpdateRecord)
+			log.Printf("%s: Unable to directly update records yet. Record: %+v", domain.Domain, toUpdateRecord)
+			continue
 		}
 
-		log.Printf("%s: trying to update `%s` : `%s`", domain, toUpdateRecord.Type, toUpdateRecord.Name)
+		var currentIP string
+		if toUpdateRecord.Type == "A" {
+			currentIP = ipv4.String()
+		} else if ipv6 == nil || ipv6.To4() != nil {
+			if ipv6 == nil {
+				ipv6 = ipv4
+			}
+
+			log.Printf("%s: You are trying to update an IPv6 AAAA record without an IPv6 address: ip: %s config: %+v",
+				domain.Domain,
+				ipv6,
+				toUpdateRecord,
+			)
+			if config.AllowIPv4InIPv6 {
+				currentIP = toIPv6String(ipv6)
+				log.Printf("%s: Converting IPv4 `%s` to IPv6 `%s`", domain.Domain, ipv6.String(), currentIP)
+			} else {
+				continue
+			}
+		} else {
+			currentIP = ipv6.String()
+		}
+
+		log.Printf("%s: trying to update `%s` : `%s`", domain.Domain, toUpdateRecord.Type, toUpdateRecord.Name)
 		for _, doRecord := range doRecords {
-			//log.Printf("%s: checking `%s` : `%s`", domain, doRecord.Type, doRecord.Name)
+			//log.Printf("%s: checking `%s` : `%s`", domain.Domain, doRecord.Type, doRecord.Name)
 			if doRecord.Name == toUpdateRecord.Name && doRecord.Type == toUpdateRecord.Type {
 				if doRecord.Data == currentIP && (toUpdateRecord.TTL < 30 || doRecord.TTL == toUpdateRecord.TTL) {
-					log.Printf("%s: IP/TTL did not change %+v", domain, doRecord)
+					log.Printf("%s: IP/TTL did not change %+v", domain.Domain, doRecord)
 					continue
 				}
-				log.Printf("%s: updating %+v", domain, doRecord)
+				log.Printf("%s: updating %+v", domain.Domain, doRecord)
 				// set the IP address
 				doRecord.Data = currentIP
 				if toUpdateRecord.TTL >= 30 && doRecord.TTL != toUpdateRecord.TTL {
@@ -205,7 +266,7 @@ func UpdateRecords(domain string, ip net.IP, toUpdateRecords []DNSRecord) {
 				checkError(err)
 				client := &http.Client{}
 				request, err := http.NewRequest("PUT",
-					"https://api.digitalocean.com/v2/domains/"+url.PathEscape(domain)+"/records/"+strconv.FormatInt(int64(doRecord.ID), 10),
+					"https://api.digitalocean.com/v2/domains/"+url.PathEscape(domain.Domain)+"/records/"+strconv.FormatInt(int64(doRecord.ID), 10),
 					bytes.NewBuffer(update))
 				checkError(err)
 				request.Header.Set("Content-Type", "application/json")
@@ -214,26 +275,63 @@ func UpdateRecords(domain string, ip net.IP, toUpdateRecords []DNSRecord) {
 				checkError(err)
 				defer response.Body.Close()
 				body, err := ioutil.ReadAll(response.Body)
-				log.Printf("%s: DO update response for %s: %s\n", domain, doRecord.Name, string(body))
+				log.Printf("%s: DO update response for %s: %s", domain.Domain, doRecord.Name, string(body))
 				updated++
 			}
 		}
 
 	}
-	log.Printf("%s: %d of %d records updated\n", domain, updated, len(toUpdateRecords))
+	log.Printf("%s: %d of %d records updated", domain.Domain, updated, len(domain.Records))
+}
+
+// toIPv6String : net.IP.String will always output an IPv4 address in dot
+// notation (127.0.0.1) even if we convert it using net.IP.To16().
+// For AAAA records, we can't have that. Instead, force the
+// IP to have the IPv6 colon notation.
+func toIPv6String(ip net.IP) (currentIP string) {
+	if ip == nil {
+		return ""
+	}
+	if ipv4 := ip.To4(); ipv4 != nil {
+		ip = ipv4
+	}
+	l := len(ip)
+	if l < 16 {
+		// ensure "v4InV6Prefix" for IPv4 addresses
+		currentIP = "::ffff:"
+	}
+	// byte length of an ipv6 segment.
+	segSize := 2
+	for i := 0; i < l; i += segSize {
+		end := i + segSize
+		bs := ip[i:end]
+		addColon := (end + 1) < l
+		currentIP += hex.EncodeToString(bs)
+		if addColon {
+			currentIP += ":"
+		}
+	}
+	return currentIP
+}
+
+func areZero(bs []byte) bool {
+	for _, b := range bs {
+		if b != 0 {
+			return false
+		}
+	}
+	return true
 }
 
 func main() {
 	config = GetConfig()
-	currentIP := CheckLocalIP()
+	currentIPv4, currentIPv6 := CheckLocalIPs()
-	ip := net.ParseIP(currentIP)
+	if currentIPv4 == nil && currentIPv6 == nil {
-	if ip == nil {
+		log.Fatal("current IP addresses are not a valid, or both are disabled in the config. Check you configuration and internet connection")
-		log.Fatalf("current IP address `%s` is not a valid IP address", currentIP)
 	}
 	for _, domain := range config.Domains {
-		domainName := domain.Domain
+		log.Printf("%s: START", domain.Domain)
-		log.Printf("%s: START\n", domainName)
+		UpdateRecords(domain, currentIPv4, currentIPv6)
-		UpdateRecords(domainName, ip, domain.Records)
+		log.Printf("%s: END", domain.Domain)
-		log.Printf("%s: END\n", domainName)
 	}
 }

digitalocean-dynamic-ip.sample.json

@@ -1,6 +1,9 @@
 {
   "apikey": "samplekeydasjkdhaskjdhrwofihsamplekey",
-  "doPageSize" : 20,
+  "doPageSize": 20,
+  "useIPv4": true,
+  "useIPv6": true,
+  "allowIPv4InIPv6": false,
   "domains": [
     {
       "domain": "example.com",