diff --git a/ipn/ipnserver/server.go b/ipn/ipnserver/server.go index fe091af84..fb63de133 100644 --- a/ipn/ipnserver/server.go +++ b/ipn/ipnserver/server.go @@ -8,22 +8,29 @@ import ( "bufio" "context" "fmt" + "html" + "io" "log" "net" "net/http" "os" "os/exec" "os/signal" + "os/user" + "runtime" "sync" "syscall" "time" + "inet.af/netaddr" "tailscale.com/control/controlclient" "tailscale.com/ipn" "tailscale.com/logtail/backoff" + "tailscale.com/net/netstat" "tailscale.com/safesocket" "tailscale.com/smallzstd" "tailscale.com/types/logger" + "tailscale.com/util/pidowner" "tailscale.com/version" "tailscale.com/wgengine" ) @@ -84,11 +91,22 @@ type server struct { } func (s *server) serveConn(ctx context.Context, c net.Conn, logf logger.Logf) { + br := bufio.NewReader(c) + + // First see if it's an HTTP request. + c.SetReadDeadline(time.Now().Add(time.Second)) + peek, _ := br.Peek(4) + c.SetReadDeadline(time.Time{}) + if string(peek) == "GET " { + http.Serve(&oneConnListener{altReaderNetConn{br, c}}, localhostHandler(c)) + return + } + s.addConn(c) logf("incoming control connection") defer s.removeAndCloseConn(c) for ctx.Err() == nil { - msg, err := ipn.ReadMsg(c) + msg, err := ipn.ReadMsg(br) if err != nil { if ctx.Err() == nil { logf("ReadMsg: %v", err) @@ -394,3 +412,83 @@ func BabysitProc(ctx context.Context, args []string, logf logger.Logf) { func FixedEngine(eng wgengine.Engine) func() (wgengine.Engine, error) { return func() (wgengine.Engine, error) { return eng, nil } } + +type dummyAddr string +type oneConnListener struct { + conn net.Conn +} + +func (l *oneConnListener) Accept() (c net.Conn, err error) { + c = l.conn + if c == nil { + err = io.EOF + return + } + err = nil + l.conn = nil + return +} + +func (l *oneConnListener) Close() error { return nil } + +func (l *oneConnListener) Addr() net.Addr { return dummyAddr("unused-address") } + +func (a dummyAddr) Network() string { return string(a) } +func (a dummyAddr) String() string { return string(a) } + +type altReaderNetConn struct { + r io.Reader + net.Conn +} + +func (a altReaderNetConn) Read(p []byte) (int, error) { return a.r.Read(p) } + +func localhostHandler(c net.Conn) http.Handler { + la, lerr := netaddr.ParseIPPort(c.LocalAddr().String()) + ra, rerr := netaddr.ParseIPPort(c.RemoteAddr().String()) + return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + fmt.Fprintf(w, "

tailscale

\n") + if lerr != nil || rerr != nil { + io.WriteString(w, "failed to parse remote address") + return + } + if !la.IP.IsLoopback() || !ra.IP.IsLoopback() { + io.WriteString(w, "not loopback") + return + } + tab, err := netstat.Get() + if err == netstat.ErrNotImplemented { + io.WriteString(w, "status page not available on "+runtime.GOOS) + return + } + if err != nil { + io.WriteString(w, "failed to get netstat table") + return + } + pid := peerPid(tab.Entries, la, ra) + if pid == 0 { + io.WriteString(w, "peer pid not found") + return + } + uid, err := pidowner.OwnerOfPID(pid) + if err != nil { + io.WriteString(w, "owner of peer pid not found") + return + } + u, err := user.LookupId(uid) + if err != nil { + io.WriteString(w, "User lookup failed") + return + } + fmt.Fprintf(w, "Hello, %s", html.EscapeString(u.Username)) + }) +} + +func peerPid(entries []netstat.Entry, la, ra netaddr.IPPort) int { + for _, e := range entries { + if e.Local == ra && e.Remote == la { + return e.Pid + } + } + return 0 +}