cmd/tailscale/cli: add debug 2021 --verbose flag

Change-Id: Ic93c2a8451518755fb44b5c35272d9b9353fe4d4
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/tailscale/cli/debug.go

@@ -18,6 +18,7 @@ import (
 	"net"
 	"net/http"
 	"net/netip"
+	"net/url"
 	"os"
 	"runtime"
 	"strconv"
@@ -25,14 +26,17 @@ import (
 	"time"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
+	"golang.org/x/net/http/httpproxy"
 	"tailscale.com/control/controlhttp"
 	"tailscale.com/hostinfo"
 	"tailscale.com/ipn"
 	"tailscale.com/net/tsaddr"
+	"tailscale.com/net/tshttpproxy"
 	"tailscale.com/paths"
 	"tailscale.com/safesocket"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/key"
+	"tailscale.com/types/logger"
 )
 
 var debugCmd = &ffcli.Command{
@@ -141,6 +145,7 @@ var debugCmd = &ffcli.Command{
 				fs := newFlagSet("ts2021")
 				fs.StringVar(&ts2021Args.host, "host", "controlplane.tailscale.com", "hostname of control plane")
 				fs.IntVar(&ts2021Args.version, "version", int(tailcfg.CurrentCapabilityVersion), "protocol version")
+				fs.BoolVar(&ts2021Args.verbose, "verbose", false, "be extra verbose")
 				return fs
 			})(),
 		},
@@ -465,19 +470,35 @@ func runVia(ctx context.Context, args []string) error {
 var ts2021Args struct {
 	host    string // "controlplane.tailscale.com"
 	version int    // 27 or whatever
+	verbose bool
 }
 
 func runTS2021(ctx context.Context, args []string) error {
 	log.SetOutput(os.Stdout)
 	log.SetFlags(log.Ltime | log.Lmicroseconds)
 
+	keysURL := "https://" + ts2021Args.host + "/key?v=" + strconv.Itoa(ts2021Args.version)
+
+	if ts2021Args.verbose {
+		u, err := url.Parse(keysURL)
+		if err != nil {
+			return err
+		}
+		envConf := httpproxy.FromEnvironment()
+		if *envConf == (httpproxy.Config{}) {
+			log.Printf("HTTP proxy env: (none)")
+		} else {
+			log.Printf("HTTP proxy env: %+v", envConf)
+		}
+		proxy, err := tshttpproxy.ProxyFromEnvironment(&http.Request{URL: u})
+		log.Printf("tshttpproxy.ProxyFromEnvironment = (%v, %v)", proxy, err)
+	}
 	machinePrivate := key.NewMachine()
 	var dialer net.Dialer
 
 	var keys struct {
 		PublicKey key.MachinePublic
 	}
-	keysURL := "https://" + ts2021Args.host + "/key?v=" + strconv.Itoa(ts2021Args.version)
 	log.Printf("Fetching keys from %s ...", keysURL)
 	req, err := http.NewRequestWithContext(ctx, "GET", keysURL, nil)
 	if err != nil {
@@ -497,6 +518,9 @@ func runTS2021(ctx context.Context, args []string) error {
 		return fmt.Errorf("decoding /keys JSON: %w", err)
 	}
 	res.Body.Close()
+	if ts2021Args.verbose {
+		log.Printf("got public key: %v", keys.PublicKey)
+	}
 
 	dialFunc := func(ctx context.Context, network, address string) (net.Conn, error) {
 		log.Printf("Dial(%q, %q) ...", network, address)
@@ -508,7 +532,10 @@ func runTS2021(ctx context.Context, args []string) error {
 		}
 		return c, err
 	}
-
+	var logf logger.Logf
+	if ts2021Args.verbose {
+		logf = log.Printf
+	}
 	conn, err := (&controlhttp.Dialer{
 		Hostname:        ts2021Args.host,
 		HTTPPort:        "80",
@@ -517,6 +544,7 @@ func runTS2021(ctx context.Context, args []string) error {
 		ControlKey:      keys.PublicKey,
 		ProtocolVersion: uint16(ts2021Args.version),
 		Dialer:          dialFunc,
+		Logf:            logf,
 	}).Dial(ctx)
 	log.Printf("controlhttp.Dial = %p, %v", conn, err)
 	if err != nil {

cmd/tailscale/depaware.txt

@@ -129,7 +129,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from net/http+
-        golang.org/x/net/http/httpproxy                              from net/http
+        golang.org/x/net/http/httpproxy                              from net/http+
         golang.org/x/net/http2/hpack                                 from net/http
         golang.org/x/net/icmp                                        from tailscale.com/net/ping
         golang.org/x/net/idna                                        from golang.org/x/net/http/httpguts+