From 05e07e8b692c628ba3542a3e180fbb1145b4e5ed Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Sun, 21 Jan 2018 18:02:32 +0100
Subject: [PATCH] Add a simple built-in DNS client for testing

---
 dnscrypt-proxy/config.go  |  5 ++++
 dnscrypt-proxy/main.go    |  3 +-
 dnscrypt-proxy/resolve.go | 60 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 dnscrypt-proxy/resolve.go

diff --git a/dnscrypt-proxy/config.go b/dnscrypt-proxy/config.go
index fbfbed39..f609d9b8 100644
--- a/dnscrypt-proxy/config.go
+++ b/dnscrypt-proxy/config.go
@@ -104,6 +104,7 @@ type BlockIPConfig struct {
 func ConfigLoad(proxy *Proxy, svcFlag *string, config_file string) error {
 	version := flag.Bool("version", false, "prints current proxy version")
 	configFile := flag.String("config", "dnscrypt-proxy.toml", "path to the configuration file")
+	resolve := flag.String("resolve", "", "resolve a name using system libraries")
 	flag.Parse()
 	if *svcFlag == "stop" || *svcFlag == "uninstall" {
 		return nil
@@ -112,6 +113,10 @@ func ConfigLoad(proxy *Proxy, svcFlag *string, config_file string) error {
 		fmt.Println(AppVersion)
 		os.Exit(0)
 	}
+	if resolve != nil && len(*resolve) > 0 {
+		Resolve(*resolve)
+		os.Exit(0)
+	}
 	config := newConfig()
 	if _, err := toml.DecodeFile(*configFile, &config); err != nil {
 		return err
diff --git a/dnscrypt-proxy/main.go b/dnscrypt-proxy/main.go
index 8e9ac79d..1ea81411 100644
--- a/dnscrypt-proxy/main.go
+++ b/dnscrypt-proxy/main.go
@@ -60,7 +60,6 @@ type App struct {
 
 func main() {
 	dlog.Init("dnscrypt-proxy", dlog.SeverityNotice, "DAEMON")
-	dlog.Noticef("Starting dnscrypt-proxy %s", AppVersion)
 
 	cdLocal()
 
@@ -80,6 +79,8 @@ func main() {
 	if err := ConfigLoad(&app.proxy, svcFlag, "dnscrypt-proxy.toml"); err != nil {
 		dlog.Fatal(err)
 	}
+	dlog.Noticef("Starting dnscrypt-proxy %s", AppVersion)
+
 	if len(*svcFlag) != 0 {
 		if err := service.Control(svc, *svcFlag); err != nil {
 			dlog.Fatal(err)
diff --git a/dnscrypt-proxy/resolve.go b/dnscrypt-proxy/resolve.go
new file mode 100644
index 00000000..7d50b08c
--- /dev/null
+++ b/dnscrypt-proxy/resolve.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"strings"
+)
+
+const myResolverHost string = "resolver.dnscrypt.info"
+
+func Resolve(name string) {
+	fmt.Printf("Resolving [%s]\n\n", name)
+
+	fmt.Printf("Domain exists:  ")
+	ns, err := net.LookupNS(name)
+	if err != nil || len(ns) == 0 {
+		if name == "." {
+			fmt.Println("'No' would mean that the Internet doesn't exist any more, and that would be very sad. On the bright side, you just found an easter egg.")
+		} else {
+			fmt.Println("probably not, or blocked by the proxy")
+		}
+	} else {
+		fmt.Printf("yes, %d name servers found\n", len(ns))
+	}
+
+	fmt.Printf("Canonical name: ")
+	cname, err := net.LookupCNAME(name)
+	if err != nil {
+		fmt.Println("-")
+	} else {
+		fmt.Println(cname)
+	}
+
+	fmt.Printf("IP addresses:   ")
+	addrs, err := net.LookupHost(name)
+	if err != nil {
+		fmt.Println("-")
+	} else {
+		fmt.Println(strings.Join(addrs, ", "))
+	}
+
+	fmt.Printf("TXT records:    ")
+	txt, err := net.LookupTXT(name)
+	if err != nil {
+		fmt.Println("-")
+	} else {
+		fmt.Println(strings.Join(txt, " "))
+	}
+
+	resIP, err := net.LookupHost(myResolverHost)
+	if err == nil && len(resIP) > 0 {
+		fmt.Printf("Resolver IP:    %s", resIP[0])
+		rev, err := net.LookupAddr(resIP[0])
+		if err == nil && len(rev) > 0 {
+			fmt.Printf(" (%s)", rev[0])
+		}
+		fmt.Println("")
+	}
+	fmt.Println("")
+}