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c126467 Jul 23, 2018
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@x1ddos @bradfitz
158 lines (144 sloc) 4.45 KB
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package autocert
import (
"crypto/tls"
"log"
"net"
"os"
"path/filepath"
"runtime"
"time"
)
// NewListener returns a net.Listener that listens on the standard TLS
// port (443) on all interfaces and returns *tls.Conn connections with
// LetsEncrypt certificates for the provided domain or domains.
//
// It enables one-line HTTPS servers:
//
// log.Fatal(http.Serve(autocert.NewListener("example.com"), handler))
//
// NewListener is a convenience function for a common configuration.
// More complex or custom configurations can use the autocert.Manager
// type instead.
//
// Use of this function implies acceptance of the LetsEncrypt Terms of
// Service. If domains is not empty, the provided domains are passed
// to HostWhitelist. If domains is empty, the listener will do
// LetsEncrypt challenges for any requested domain, which is not
// recommended.
//
// Certificates are cached in a "golang-autocert" directory under an
// operating system-specific cache or temp directory. This may not
// be suitable for servers spanning multiple machines.
//
// The returned listener uses a *tls.Config that enables HTTP/2, and
// should only be used with servers that support HTTP/2.
//
// The returned Listener also enables TCP keep-alives on the accepted
// connections. The returned *tls.Conn are returned before their TLS
// handshake has completed.
func NewListener(domains ...string) net.Listener {
m := &Manager{
Prompt: AcceptTOS,
}
if len(domains) > 0 {
m.HostPolicy = HostWhitelist(domains...)
}
dir := cacheDir()
if err := os.MkdirAll(dir, 0700); err != nil {
log.Printf("warning: autocert.NewListener not using a cache: %v", err)
} else {
m.Cache = DirCache(dir)
}
return m.Listener()
}
// Listener listens on the standard TLS port (443) on all interfaces
// and returns a net.Listener returning *tls.Conn connections.
//
// The returned listener uses a *tls.Config that enables HTTP/2, and
// should only be used with servers that support HTTP/2.
//
// The returned Listener also enables TCP keep-alives on the accepted
// connections. The returned *tls.Conn are returned before their TLS
// handshake has completed.
//
// Unlike NewListener, it is the caller's responsibility to initialize
// the Manager m's Prompt, Cache, HostPolicy, and other desired options.
func (m *Manager) Listener() net.Listener {
ln := &listener{
m: m,
conf: m.TLSConfig(),
}
ln.tcpListener, ln.tcpListenErr = net.Listen("tcp", ":443")
return ln
}
type listener struct {
m *Manager
conf *tls.Config
tcpListener net.Listener
tcpListenErr error
}
func (ln *listener) Accept() (net.Conn, error) {
if ln.tcpListenErr != nil {
return nil, ln.tcpListenErr
}
conn, err := ln.tcpListener.Accept()
if err != nil {
return nil, err
}
tcpConn := conn.(*net.TCPConn)
// Because Listener is a convenience function, help out with
// this too. This is not possible for the caller to set once
// we return a *tcp.Conn wrapping an inaccessible net.Conn.
// If callers don't want this, they can do things the manual
// way and tweak as needed. But this is what net/http does
// itself, so copy that. If net/http changes, we can change
// here too.
tcpConn.SetKeepAlive(true)
tcpConn.SetKeepAlivePeriod(3 * time.Minute)
return tls.Server(tcpConn, ln.conf), nil
}
func (ln *listener) Addr() net.Addr {
if ln.tcpListener != nil {
return ln.tcpListener.Addr()
}
// net.Listen failed. Return something non-nil in case callers
// call Addr before Accept:
return &net.TCPAddr{IP: net.IP{0, 0, 0, 0}, Port: 443}
}
func (ln *listener) Close() error {
if ln.tcpListenErr != nil {
return ln.tcpListenErr
}
return ln.tcpListener.Close()
}
func homeDir() string {
if runtime.GOOS == "windows" {
return os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
}
if h := os.Getenv("HOME"); h != "" {
return h
}
return "/"
}
func cacheDir() string {
const base = "golang-autocert"
switch runtime.GOOS {
case "darwin":
return filepath.Join(homeDir(), "Library", "Caches", base)
case "windows":
for _, ev := range []string{"APPDATA", "CSIDL_APPDATA", "TEMP", "TMP"} {
if v := os.Getenv(ev); v != "" {
return filepath.Join(v, base)
}
}
// Worst case:
return filepath.Join(homeDir(), base)
}
if xdg := os.Getenv("XDG_CACHE_HOME"); xdg != "" {
return filepath.Join(xdg, base)
}
return filepath.Join(homeDir(), ".cache", base)
}