tailscale/cmd/hello/hello.go

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// 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 (
"context"
"encoding/json"
"flag"
"fmt"
"html/template"
"io/ioutil"
"log"
"net"
"net/http"
"net/url"
"os"
"strconv"
"strings"
"tailscale.com/safesocket"
"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")
testIP = flag.String("test-ip", "", "if non-empty, look up IP and exit before running a server")
)
func main() {
flag.Parse()
if *testIP != "" {
res, err := whoIs(*testIP)
if err != nil {
log.Fatal(err)
}
e := json.NewEncoder(os.Stdout)
e.SetIndent("", "\t")
e.Encode(res)
return
}
if !devMode() {
tmpl = template.Must(template.New("home").Parse(slurpHTML()))
}
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)
}
func devMode() bool { return *httpsAddr == "" && *httpAddr != "" }
func getTmpl() (*template.Template, error) {
if devMode() {
return template.New("home").Parse(slurpHTML())
}
return tmpl, nil
}
var tmpl *template.Template // not used in dev mode, initialized by main after flag parse
type tmplData struct {
DisplayName string // "Foo Barberson"
LoginName string // "foo@bar.com"
ProfilePicURL string // "https://..."
MachineName string // "imac5k"
MachineOS string // "Linux"
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
}
tmpl, err := getTmpl()
if err != nil {
w.Header().Set("Content-Type", "text/plain")
http.Error(w, "template error: "+err.Error(), 500)
return
}
who, err := whoIs(ip)
var data tmplData
if err != nil {
if devMode() {
log.Printf("warning: using fake data in dev mode due to whois lookup error: %v", err)
data = tmplData{
DisplayName: "Taily Scalerson",
LoginName: "taily@scaler.son",
ProfilePicURL: "https://placekitten.com/200/200",
MachineName: "scaled",
MachineOS: "Linux",
IP: "100.1.2.3",
}
} else {
log.Printf("whois(%q) error: %v", ip, err)
http.Error(w, "Your Tailscale works, but we failed to look you up.", 500)
return
}
} else {
data = tmplData{
DisplayName: who.UserProfile.DisplayName,
LoginName: who.UserProfile.LoginName,
ProfilePicURL: who.UserProfile.ProfilePicURL,
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MachineName: firstLabel(who.Node.ComputedName),
MachineOS: who.Node.Hostinfo.OS,
IP: ip,
}
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
tmpl.Execute(w, data)
}
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// firstLabel s up until the first period, if any.
func firstLabel(s string) string {
if i := strings.Index(s, "."); i != -1 {
return s[:i]
}
return s
}
// tsSockClient does HTTP requests to the local Tailscale daemon.
// The hostname in the HTTP request is ignored.
var tsSockClient = &http.Client{
Transport: &http.Transport{
DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
// On macOS, when dialing from non-sandboxed program to sandboxed GUI running
// a TCP server on a random port, find the random port. For HTTP connections,
// we don't send the token. It gets added in an HTTP Basic-Auth header.
if port, _, err := safesocket.LocalTCPPortAndToken(); err == nil {
var d net.Dialer
return d.DialContext(ctx, "tcp", "localhost:"+strconv.Itoa(port))
}
return safesocket.ConnectDefault()
},
},
}
func whoIs(ip string) (*tailcfg.WhoIsResponse, error) {
ctx := context.Background()
req, err := http.NewRequestWithContext(ctx, "GET", "http://local-tailscaled.sock/localapi/v0/whois?ip="+url.QueryEscape(ip), nil)
if err != nil {
return nil, err
}
if _, token, err := safesocket.LocalTCPPortAndToken(); err == nil {
req.SetBasicAuth("", token)
}
res, err := tsSockClient.Do(req)
if err != nil {
return nil, err
}
defer res.Body.Close()
slurp, _ := ioutil.ReadAll(res.Body)
if res.StatusCode != 200 {
return nil, fmt.Errorf("HTTP %s: %s", res.Status, slurp)
}
r := new(tailcfg.WhoIsResponse)
if err := json.Unmarshal(slurp, r); err != nil {
if max := 200; len(slurp) > max {
slurp = slurp[:max]
}
return nil, fmt.Errorf("failed to parse JSON WhoIsResponse from %q", slurp)
}
return r, nil
}