Files
coder/coderd/devtunnel/tunnel.go

342 lines
8.3 KiB
Go

package devtunnel
import (
"bytes"
"context"
"encoding/base64"
"encoding/hex"
"encoding/json"
"fmt"
"io"
"net"
"net/http"
"net/netip"
"os"
"path/filepath"
"time"
"github.com/google/uuid"
"golang.org/x/xerrors"
"golang.zx2c4.com/wireguard/conn"
"golang.zx2c4.com/wireguard/device"
"golang.zx2c4.com/wireguard/tun/netstack"
"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
"cdr.dev/slog"
"github.com/coder/coder/cryptorand"
)
var (
v0EndpointHTTPS = "wg-tunnel.coder.app"
v0ServerPublicKey = "+KNSMwed/IlqoesvTMSBNsHFaKVLrmmaCkn0bxIhUg0="
v0ServerIP = netip.AddrFrom16(uuid.MustParse("fcad0000-0000-4000-8000-000000000001"))
)
type Tunnel struct {
URL string
Listener net.Listener
}
type Config struct {
Version int `json:"version"`
ID uuid.UUID `json:"id"`
PrivateKey device.NoisePrivateKey `json:"private_key"`
PublicKey device.NoisePublicKey `json:"public_key"`
Tunnel Node `json:"tunnel"`
}
type configExt struct {
Version int `json:"-"`
ID uuid.UUID `json:"id"`
PrivateKey device.NoisePrivateKey `json:"-"`
PublicKey device.NoisePublicKey `json:"public_key"`
Tunnel Node `json:"-"`
}
// NewWithConfig calls New with the given config. For documentation, see New.
func NewWithConfig(ctx context.Context, logger slog.Logger, cfg Config) (*Tunnel, <-chan error, error) {
server, routineEnd, err := startUpdateRoutine(ctx, logger, cfg)
if err != nil {
return nil, nil, xerrors.Errorf("start update routine: %w", err)
}
tun, tnet, err := netstack.CreateNetTUN(
[]netip.Addr{server.ClientIP},
[]netip.Addr{netip.AddrFrom4([4]byte{1, 1, 1, 1})},
1280,
)
if err != nil {
return nil, nil, xerrors.Errorf("create net TUN: %w", err)
}
wgip, err := net.ResolveIPAddr("ip", cfg.Tunnel.HostnameWireguard)
if err != nil {
return nil, nil, xerrors.Errorf("resolve endpoint: %w", err)
}
dev := device.NewDevice(tun, conn.NewDefaultBind(), device.NewLogger(device.LogLevelSilent, ""))
err = dev.IpcSet(fmt.Sprintf(`private_key=%s
public_key=%s
endpoint=%s:%d
persistent_keepalive_interval=21
allowed_ip=%s/128`,
hex.EncodeToString(cfg.PrivateKey[:]),
server.ServerPublicKey,
wgip.IP.String(),
cfg.Tunnel.WireguardPort,
server.ServerIP.String(),
))
if err != nil {
return nil, nil, xerrors.Errorf("configure wireguard ipc: %w", err)
}
err = dev.Up()
if err != nil {
return nil, nil, xerrors.Errorf("wireguard device up: %w", err)
}
wgListen, err := tnet.ListenTCP(&net.TCPAddr{Port: 8090})
if err != nil {
return nil, nil, xerrors.Errorf("wireguard device listen: %w", err)
}
ch := make(chan error)
go func() {
select {
case <-ctx.Done():
_ = wgListen.Close()
dev.Close()
<-routineEnd
close(ch)
case <-dev.Wait():
close(ch)
}
}()
return &Tunnel{
URL: fmt.Sprintf("https://%s", server.Hostname),
Listener: wgListen,
}, ch, nil
}
// New creates a tunnel with a public URL and returns a listener for incoming
// connections on that URL. Connections are made over the wireguard protocol.
// Tunnel configuration is cached in the user's config directory. Successive
// calls to New will always use the same URL. If multiple public URLs in
// parallel are required, use NewWithConfig.
func New(ctx context.Context, logger slog.Logger) (*Tunnel, <-chan error, error) {
cfg, err := readOrGenerateConfig()
if err != nil {
return nil, nil, xerrors.Errorf("read or generate config: %w", err)
}
return NewWithConfig(ctx, logger, cfg)
}
func startUpdateRoutine(ctx context.Context, logger slog.Logger, cfg Config) (ServerResponse, <-chan struct{}, error) {
// Ensure we send the first config before spawning in the background.
res, err := sendConfigToServer(ctx, cfg)
if err != nil {
return ServerResponse{}, nil, xerrors.Errorf("send config to server: %w", err)
}
endCh := make(chan struct{})
go func() {
defer close(endCh)
ticker := time.NewTicker(30 * time.Second)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
return
case <-ticker.C:
}
_, err := sendConfigToServer(ctx, cfg)
if err != nil {
logger.Debug(ctx, "send tunnel config to server", slog.Error(err))
}
}
}()
return res, endCh, nil
}
type ServerResponse struct {
Hostname string `json:"hostname"`
ServerIP netip.Addr `json:"server_ip"`
ServerPublicKey string `json:"server_public_key"` // hex
ClientIP netip.Addr `json:"client_ip"`
}
func sendConfigToServer(ctx context.Context, cfg Config) (ServerResponse, error) {
raw, err := json.Marshal(configExt(cfg))
if err != nil {
return ServerResponse{}, xerrors.Errorf("marshal config: %w", err)
}
var req *http.Request
switch cfg.Version {
case 0:
req, err = http.NewRequestWithContext(ctx, "POST", "https://"+v0EndpointHTTPS+"/tun", bytes.NewReader(raw))
if err != nil {
return ServerResponse{}, xerrors.Errorf("new request: %w", err)
}
case 1:
req, err = http.NewRequestWithContext(ctx, "POST", "https://"+cfg.Tunnel.HostnameHTTPS+"/tun", bytes.NewReader(raw))
if err != nil {
return ServerResponse{}, xerrors.Errorf("new request: %w", err)
}
default:
return ServerResponse{}, xerrors.Errorf("unknown config version: %d", cfg.Version)
}
res, err := http.DefaultClient.Do(req)
if err != nil {
return ServerResponse{}, xerrors.Errorf("do request: %w", err)
}
defer res.Body.Close()
var resp ServerResponse
switch cfg.Version {
case 0:
_, _ = io.Copy(io.Discard, res.Body)
resp.Hostname = fmt.Sprintf("%s.%s", cfg.ID, v0EndpointHTTPS)
resp.ServerIP = v0ServerIP
resp.ServerPublicKey = encodeBase64ToHex(v0ServerPublicKey)
resp.ClientIP = netip.AddrFrom16(cfg.ID)
case 1:
err := json.NewDecoder(res.Body).Decode(&resp)
if err != nil {
return ServerResponse{}, xerrors.Errorf("decode response: %w", err)
}
default:
_, _ = io.Copy(io.Discard, res.Body)
return ServerResponse{}, xerrors.Errorf("unknown config version: %d", cfg.Version)
}
return resp, nil
}
func cfgPath() (string, error) {
cfgDir, err := os.UserConfigDir()
if err != nil {
return "", xerrors.Errorf("get user config dir: %w", err)
}
cfgDir = filepath.Join(cfgDir, "coderv2")
err = os.MkdirAll(cfgDir, 0750)
if err != nil {
return "", xerrors.Errorf("mkdirall config dir %q: %w", cfgDir, err)
}
return filepath.Join(cfgDir, "devtunnel"), nil
}
func readOrGenerateConfig() (Config, error) {
cfgFi, err := cfgPath()
if err != nil {
return Config{}, xerrors.Errorf("get config path: %w", err)
}
fi, err := os.ReadFile(cfgFi)
if err != nil {
if os.IsNotExist(err) {
cfg, err := GenerateConfig()
if err != nil {
return Config{}, xerrors.Errorf("generate config: %w", err)
}
err = writeConfig(cfg)
if err != nil {
return Config{}, xerrors.Errorf("write config: %w", err)
}
return cfg, nil
}
return Config{}, xerrors.Errorf("read config: %w", err)
}
cfg := Config{}
err = json.Unmarshal(fi, &cfg)
if err != nil {
return Config{}, xerrors.Errorf("unmarshal config: %w", err)
}
if cfg.Version == 0 {
cfg.Tunnel = Node{
ID: 0,
HostnameHTTPS: "wg-tunnel.coder.app",
HostnameWireguard: "wg-tunnel-udp.coder.app",
WireguardPort: 55555,
}
}
return cfg, nil
}
func GenerateConfig() (Config, error) {
priv, err := wgtypes.GeneratePrivateKey()
if err != nil {
return Config{}, xerrors.Errorf("generate private key: %w", err)
}
pub := priv.PublicKey()
node, err := FindClosestNode()
if err != nil {
region := Regions[0]
n, _ := cryptorand.Intn(len(region.Nodes))
node = region.Nodes[n]
_, _ = fmt.Println("Error picking closest dev tunnel:", err)
_, _ = fmt.Println("Defaulting to", Regions[0].LocationName)
}
return Config{
Version: 1,
PrivateKey: device.NoisePrivateKey(priv),
PublicKey: device.NoisePublicKey(pub),
Tunnel: node,
}, nil
}
func writeConfig(cfg Config) error {
cfgFi, err := cfgPath()
if err != nil {
return xerrors.Errorf("get config path: %w", err)
}
raw, err := json.Marshal(cfg)
if err != nil {
return xerrors.Errorf("marshal config: %w", err)
}
err = os.WriteFile(cfgFi, raw, 0600)
if err != nil {
return xerrors.Errorf("write file: %w", err)
}
return nil
}
func encodeBase64ToHex(key string) string {
decoded, err := base64.StdEncoding.DecodeString(key)
if err != nil {
panic(err)
}
if len(decoded) != 32 {
panic((xerrors.New("key should be 32 bytes: " + key)))
}
return hex.EncodeToString(decoded)
}