From 512e1c86211e901c0f349f22847a5922de950d51 Mon Sep 17 00:00:00 2001
From: campbellbs <wildfire@linex-design.de>
Date: Sat, 17 Sep 2022 03:17:55 +0200
Subject: [PATCH] ipv6 support for client configuration

---
 go.mod       |  1 +
 go.sum       |  2 ++
 util/util.go | 65 ++++++++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 58 insertions(+), 10 deletions(-)

diff --git a/go.mod b/go.mod
index 6cacd1e..fd39ad8 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,7 @@ go 1.14
 
 require (
 	github.com/GeertJohan/go.rice v1.0.2
+	github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d // indirect
 	github.com/glendc/go-external-ip v0.0.0-20170425150139-139229dcdddd
 	github.com/go-playground/universal-translator v0.17.0 // indirect
 	github.com/gorilla/sessions v1.2.0
diff --git a/go.sum b/go.sum
index 607f7a1..2da2e76 100644
--- a/go.sum
+++ b/go.sum
@@ -10,6 +10,8 @@ github.com/akavel/rsrc v0.8.0/go.mod h1:uLoCtb9J+EyAqh+26kdrTgmzRBFPGOolLWKpdxkK
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/appleboy/gofight/v2 v2.1.2/go.mod h1:frW+U1QZEdDgixycTj4CygQ48yLTUhplt43+Wczp3rw=
+github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d h1:Byv0BzEl3/e6D5CLfI0j/7hiIEtvGVFPCZ7Ei2oq8iQ=
+github.com/asaskevich/govalidator v0.0.0-20210307081110-f21760c49a8d/go.mod h1:WaHUgvxTVq04UNunO+XhnAqY/wQc+bxr74GqbsZ/Jqw=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
diff --git a/util/util.go b/util/util.go
index ea97fcc..29a4c23 100644
--- a/util/util.go
+++ b/util/util.go
@@ -7,12 +7,14 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
+	"regexp"
 	"strconv"
 	"strings"
 	"text/template"
 	"time"
 
 	rice "github.com/GeertJohan/go.rice"
+	"github.com/asaskevich/govalidator"
 	externalip "github.com/glendc/go-external-ip"
 	"github.com/labstack/gommon/log"
 	"github.com/ngoduykhanh/wireguard-ui/model"
@@ -38,16 +40,10 @@ func BuildClientConfig(client model.Client, server model.Server, setting model.G
 
 	peerAllowedIPs := fmt.Sprintf("AllowedIPs = %s\n", strings.Join(client.AllowedIPs, ","))
 
-	desiredHost := setting.EndpointAddress
-	desiredPort := server.Interface.ListenPort
-	if strings.Contains(desiredHost, ":") {
-		split := strings.Split(desiredHost, ":")
-		desiredHost = split[0]
-		if n, err := strconv.Atoi(split[1]); err == nil {
-			desiredPort = n
-		} else {
-			log.Error("Endpoint appears to be incorrectly formatted: ", err)
-		}
+	desiredHost, desiredPort, err := ParseEndpoint(setting.EndpointAddress, server.Interface.ListenPort)
+
+	if err != nil {
+		log.Error("Endpoint appears to be incorrectly formatted: ", err)
 	}
 	peerEndpoint := fmt.Sprintf("Endpoint = %s:%d\n", desiredHost, desiredPort)
 
@@ -457,3 +453,52 @@ func LookupEnvOrStrings(key string, defaultVal []string) []string {
 	}
 	return defaultVal
 }
+
+func RemoveIPv6Brackets(host string) string {
+	ipv6 := host
+	if matchBrackets, _ := regexp.MatchString(`^\[.*\]$`, ipv6); matchBrackets == true {
+		ipv6 = strings.Replace(ipv6, "[", "", -1)
+		ipv6 = strings.Replace(ipv6, "]", "", -1)
+
+		//only remove brackets if valid ipv6 address
+		if govalidator.IsIPv6(ipv6) {
+			return ipv6
+		}
+	}
+	return host
+}
+
+func AddIPv6Brackets(host string) string {
+	ipv6 := host
+
+	//only add brackets if valid ipv6 address
+	if govalidator.IsIPv6(ipv6) {
+		ipv6 = "[" + ipv6 + "]"
+		return ipv6
+	}
+	return host
+}
+
+func ParseEndpoint(host string, defaultPort int) (string, int, error) {
+	port := defaultPort
+
+	//remove brackets from standalone IPv6 address
+	host = RemoveIPv6Brackets(host)
+
+	if govalidator.IsIPv4(host) || govalidator.IsIPv6(host) || govalidator.IsDNSName(host) {
+		return AddIPv6Brackets(host), port, nil
+	}
+
+	//check if specific port contained
+	host, strPort, err := net.SplitHostPort(host)
+	if err != nil {
+		return "", -1, errors.New("invalid Host")
+	}
+
+	port, err = strconv.Atoi(strPort)
+	if err != nil || port > 65535 || port < 0 {
+		return "", -1, errors.New("invalid Port")
+	}
+
+	return AddIPv6Brackets(host), port, nil
+}