// 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" _ "embed" "encoding/json" "flag" "html/template" "io/ioutil" "log" "net/http" "os" "strings" "tailscale.com/client/tailscale" "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") ) //go:embed hello.tmpl.html var embeddedTemplate string func main() { flag.Parse() if *testIP != "" { res, err := tailscale.WhoIs(context.Background(), *testIP) if err != nil { log.Fatal(err) } e := json.NewEncoder(os.Stdout) e.SetIndent("", "\t") e.Encode(res) return } if devMode() { // Parse it optimistically var err error tmpl, err = template.New("home").Parse(embeddedTemplate) if err != nil { log.Printf("ignoring template error in dev mode: %v", err) } } else { if embeddedTemplate == "" { log.Fatalf("embeddedTemplate is empty; must be build with Go 1.16+") } tmpl = template.Must(template.New("home").Parse(embeddedTemplate)) } 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 devMode() bool { return *httpsAddr == "" && *httpAddr != "" } func getTmpl() (*template.Template, error) { if devMode() { tmplData, err := ioutil.ReadFile("hello.tmpl.html") if os.IsNotExist(err) { log.Printf("using baked-in template in dev mode; can't find hello.tmpl.html in current directory") return tmpl, nil } return template.New("home").Parse(string(tmplData)) } return tmpl, nil } // tmpl is the template used in prod mode. // In dev mode it's only used if the template file doesn't exist on disk. // It's initialized by main after flag parsing. var tmpl *template.Template 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 tailscaleIP(who *tailcfg.WhoIsResponse) string { if who == nil { return "" } for _, nodeIP := range who.Node.Addresses { if nodeIP.IP.Is4() && nodeIP.IsSingleIP() { return nodeIP.IP.String() } } for _, nodeIP := range who.Node.Addresses { if nodeIP.IsSingleIP() { return nodeIP.IP.String() } } return "" } 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 } tmpl, err := getTmpl() if err != nil { w.Header().Set("Content-Type", "text/plain") http.Error(w, "template error: "+err.Error(), 500) return } who, err := tailscale.WhoIs(r.Context(), r.RemoteAddr) 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", r.RemoteAddr, 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, MachineName: firstLabel(who.Node.ComputedName), MachineOS: who.Node.Hostinfo.OS, IP: tailscaleIP(who), } } w.Header().Set("Content-Type", "text/html; charset=utf-8") tmpl.Execute(w, data) } // 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 }