2 files changed, 133 insertions, 0 deletions
diff --git a/cmd/hello/hello.go b/cmd/hello/hello.go
new file mode 100644
index 000000000..1f7439c0c
--- /dev/null
+++ b/cmd/hello/hello.go
@@ -0,0 +1,116 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The hello binary runs hello.ipn.dev.
+package main // import "tailscale.com/cmd/hello"
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"html/template"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"tailscale.com/tailcfg"
+)
+
+var (
+	httpAddr  = flag.String("http", ":80", "address to run an HTTP server on, or empty for none")
+	httpsAddr = flag.String("https", ":443", "address to run an HTTPS server on, or empty for none")
+)
+
+func main() {
+	flag.Parse()
+
+	http.HandleFunc("/", root)
+	log.Printf("Starting hello server.")
+
+	errc := make(chan error, 1)
+	if *httpAddr != "" {
+		log.Printf("running HTTP server on %s", *httpAddr)
+		go func() {
+			errc <- http.ListenAndServe(*httpAddr, nil)
+		}()
+	}
+	if *httpsAddr != "" {
+		log.Printf("running HTTPS server on %s", *httpsAddr)
+		go func() {
+			errc <- http.ListenAndServeTLS(*httpsAddr,
+				"/etc/hello/hello.ipn.dev.crt",
+				"/etc/hello/hello.ipn.dev.key",
+				nil,
+			)
+		}()
+	}
+	log.Fatal(<-errc)
+}
+
+func slurpHTML() string {
+	slurp, err := ioutil.ReadFile("hello.tmpl.html")
+	if err != nil {
+		log.Fatal(err)
+	}
+	return string(slurp)
+}
+
+var tmpl = template.Must(template.New("home").Parse(slurpHTML()))
+
+type tmplData struct {
+	DisplayName string // "Foo Barberson"
+	LoginName   string // "foo@bar.com"
+	MachineName string // "imac5k"
+	IP          string // "100.2.3.4"
+}
+
+func root(w http.ResponseWriter, r *http.Request) {
+	if r.TLS == nil && *httpsAddr != "" {
+		host := r.Host
+		if strings.Contains(r.Host, "100.101.102.103") {
+			host = "hello.ipn.dev"
+		}
+		http.Redirect(w, r, "https://"+host, http.StatusFound)
+		return
+	}
+	if r.RequestURI != "/" {
+		http.Redirect(w, r, "/", http.StatusFound)
+		return
+	}
+	ip, _, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+		http.Error(w, "no remote addr", 500)
+		return
+	}
+	who, err := whoIs(ip)
+	if err != nil {
+		log.Printf("whois(%q) error: %v", ip, err)
+		http.Error(w, "Your Tailscale works, but we failed to look you up.", 500)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	tmpl.Execute(w, tmplData{
+		DisplayName: who.UserProfile.DisplayName,
+		LoginName:   who.UserProfile.LoginName,
+		MachineName: who.Node.ComputedName,
+		IP:          ip,
+	})
+}
+
+func whoIs(ip string) (*tailcfg.WhoIsResponse, error) {
+	res, err := http.Get("http://127.0.0.1:4242/whois?ip=" + url.QueryEscape(ip))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	if res.StatusCode != 200 {
+		slurp, _ := ioutil.ReadAll(res.Body)
+		return nil, fmt.Errorf("HTTP %s: %s", res.Status, slurp)
+	}
+	r := new(tailcfg.WhoIsResponse)
+	return r, json.NewDecoder(res.Body).Decode(r)
+}
diff --git a/cmd/hello/hello.tmpl.html b/cmd/hello/hello.tmpl.html
new file mode 100644
index 000000000..bf43b65ac
--- /dev/null
+++ b/cmd/hello/hello.tmpl.html
@@ -0,0 +1,17 @@
+<html>
+  <head>
+    <title>Hello from Tailscale</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>
+      Hello {{.DisplayName}} ({{.LoginName}}) from {{.MachineName}} ({{.IP}}).
+    </p>
+    <p>
+      <b>Your Tailscale is working!</b>
+    </p>
+    <p>
+      Welcome to Tailscale.
+    </p>
+  </body>
+</html>