cmd/tailscale/cli: add push subcommand

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

cmd/tailscale/cli/cli.go

@@ -69,6 +69,7 @@ change in the future.
 			pingCmd,
 			versionCmd,
 			webCmd,
+			pushCmd,
 		},
 		FlagSet:   rootfs,
 		Exec:      func(context.Context, []string) error { return flag.ErrHelp },

cmd/tailscale/cli/push.go

@@ -0,0 +1,155 @@
+// 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.
+
+package cli
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"mime"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"time"
+
+	"github.com/peterbourgon/ff/v2/ffcli"
+	"tailscale.com/ipn"
+	"tailscale.com/ipn/ipnstate"
+)
+
+var pushCmd = &ffcli.Command{
+	Name:       "push",
+	ShortUsage: "push [--flags] <hostname-or-IP> <file>",
+	ShortHelp:  "Push a file to a host",
+	Exec:       runPush,
+	FlagSet: (func() *flag.FlagSet {
+		fs := flag.NewFlagSet("push", flag.ExitOnError)
+		fs.StringVar(&pushArgs.name, "name", "", "alternate filename to use, especially useful when <file> is \"-\" (stdin)")
+		fs.BoolVar(&pushArgs.verbose, "verbose", false, "verbose output")
+		return fs
+	})(),
+}
+
+var pushArgs struct {
+	name    string
+	verbose bool
+}
+
+func runPush(ctx context.Context, args []string) error {
+	if len(args) != 2 || args[0] == "" {
+		return errors.New("usage: push <hostname-or-IP> <file>")
+	}
+	var ip string
+
+	hostOrIP, fileArg := args[0], args[1]
+	ip, err := tailscaleIPFromArg(ctx, hostOrIP)
+	if err != nil {
+		return err
+	}
+
+	peerAPIPort, err := discoverPeerAPIPort(ctx, ip)
+	if err != nil {
+		return err
+	}
+
+	var fileContents io.Reader
+	var name = pushArgs.name
+	if fileArg == "-" {
+		fileContents = os.Stdin
+		if name == "" {
+			sniff, err := io.ReadAll(io.LimitReader(fileContents, 4<<20))
+			if err != nil {
+				return err
+			}
+			if exts, _ := mime.ExtensionsByType(http.DetectContentType(sniff)); len(exts) > 0 {
+				name = "stdin" + exts[0]
+			} else {
+				name = "stdin.txt"
+			}
+			fileContents = io.MultiReader(bytes.NewReader(sniff), fileContents)
+		}
+	} else {
+		f, err := os.Open(fileArg)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		fileContents = f
+		if name == "" {
+			name = fileArg
+		}
+	}
+
+	dstURL := "http://" + net.JoinHostPort(ip, fmt.Sprint(peerAPIPort)) + "/v0/put/" + url.PathEscape(name)
+	req, err := http.NewRequestWithContext(ctx, "PUT", dstURL, fileContents)
+	if err != nil {
+		return err
+	}
+	if pushArgs.verbose {
+		log.Printf("sending to %v ...", dstURL)
+	}
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	if res.StatusCode == 200 {
+		return nil
+	}
+	io.Copy(os.Stdout, res.Body)
+	return errors.New(res.Status)
+}
+
+func discoverPeerAPIPort(ctx context.Context, ip string) (port uint16, err error) {
+	c, bc, ctx, cancel := connect(ctx)
+	defer cancel()
+
+	prc := make(chan *ipnstate.PingResult, 2)
+	bc.SetNotifyCallback(func(n ipn.Notify) {
+		if n.ErrMessage != nil {
+			log.Fatal(*n.ErrMessage)
+		}
+		if pr := n.PingResult; pr != nil && pr.IP == ip {
+			prc <- pr
+		}
+	})
+	go pump(ctx, bc, c)
+
+	ticker := time.NewTicker(time.Second)
+	defer ticker.Stop()
+
+	discoPings := 0
+	timer := time.NewTimer(10 * time.Second)
+	defer timer.Stop()
+
+	sendPings := func() {
+		bc.Ping(ip, false)
+		bc.Ping(ip, true)
+	}
+	sendPings()
+	for {
+		select {
+		case <-ticker.C:
+			sendPings()
+		case <-timer.C:
+			return 0, fmt.Errorf("timeout contacting %v; it offline?", ip)
+		case pr := <-prc:
+			if p := pr.PeerAPIPort; p != 0 {
+				return p, nil
+			}
+			discoPings++
+			if discoPings == 3 {
+				return 0, fmt.Errorf("%v is online, but seems to be running an old Tailscale version", ip)
+			}
+		case <-ctx.Done():
+			return 0, ctx.Err()
+		}
+	}
+}