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client.go
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client.go
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package chclient
import (
"context"
"fmt"
"io"
"net"
"net/http"
"net/url"
"regexp"
"strings"
"time"
"os"
"github.com/pariseed/websocket"
"github.com/jpillora/backoff"
"github.com/launchdarkly/go-ntlm-proxy-auth"
chshare "github.com/jpillora/chisel/share"
"golang.org/x/crypto/ssh"
)
var isntlm bool = false
var ntlmdomain = ""
var ntlmusr = ""
var ntlmpwd = ""
var ntlmurl = ""
var Stop string
//Config represents a client configuration
type Config struct {
shared *chshare.Config
Fingerprint string
Auth string
KeepAlive time.Duration
MaxRetryCount int
MaxRetryInterval time.Duration
Server string
HTTPProxy string
Remotes []string
HostHeader string
}
//Client represents a client instance
type Client struct {
*chshare.Logger
config *Config
sshConfig *ssh.ClientConfig
sshConn ssh.Conn
httpProxyURL *url.URL
server string
running bool
runningc chan error
connStats chshare.ConnStats
}
//NewClient creates a new client instance
func NewClient(config *Config) (*Client, error) {
//apply default scheme
if !strings.HasPrefix(config.Server, "http") {
config.Server = "http://" + config.Server
}
if config.MaxRetryInterval < time.Second {
config.MaxRetryInterval = 5 * time.Minute
}
u, err := url.Parse(config.Server)
if err != nil {
return nil, err
}
//apply default port
if !regexp.MustCompile(`:\d+$`).MatchString(u.Host) {
if u.Scheme == "https" || u.Scheme == "wss" {
u.Host = u.Host + ":443"
} else {
u.Host = u.Host + ":80"
}
}
//swap to websockets scheme
u.Scheme = strings.Replace(u.Scheme, "http", "ws", 1)
shared := &chshare.Config{}
for _, s := range config.Remotes {
r, err := chshare.DecodeRemote(s)
if err != nil {
return nil, fmt.Errorf("Failed to decode remote '%s': %s", s, err)
}
shared.Remotes = append(shared.Remotes, r)
}
config.shared = shared
client := &Client{
Logger: chshare.NewLogger("client"),
config: config,
server: u.String(),
running: true,
runningc: make(chan error, 1),
}
client.Info = true
if p := config.HTTPProxy; p != "" {
urlrgx := regexp.MustCompile("htt.*://")
ntlmrgx := regexp.MustCompile("(NTLM)þ(.*):(.*):(.*)@")
ntlmfind := ntlmrgx.FindStringSubmatch(p)
if len(ntlmfind) == 0 {
;;
} else {
isntlm = true
ntlmdomain = ntlmfind[2]
ntlmusr = ntlmfind[3]
ntlmpwd = ntlmfind[4]
p = ntlmrgx.ReplaceAllString(p, "")
ntlmurl = urlrgx.ReplaceAllString(p, "")
}
client.httpProxyURL, err = url.Parse(p)
if err != nil {
return nil, fmt.Errorf("Invalid proxy URL (%s)", err)
}
client.httpProxyURL.Scheme = websocket.Scheme
}
user, pass := chshare.ParseAuth(config.Auth)
client.sshConfig = &ssh.ClientConfig{
User: user,
Auth: []ssh.AuthMethod{ssh.Password(pass)},
ClientVersion: "SSH-" + chshare.ProtocolVersion + "-client",
HostKeyCallback: client.verifyServer,
Timeout: 30 * time.Second,
}
return client, nil
}
//Run starts client and blocks while connected
func (c *Client) Run() error {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
if err := c.Start(ctx); err != nil {
return err
}
return c.Wait()
}
func (c *Client) verifyServer(hostname string, remote net.Addr, key ssh.PublicKey) error {
expect := c.config.Fingerprint
got := chshare.FingerprintKey(key)
if expect != "" && !strings.HasPrefix(got, expect) {
return fmt.Errorf("Invalid fingerprint (%s)", got)
}
//overwrite with complete fingerprint
c.Infof("Fingerprint %s", got)
return nil
}
//Start client and does not block
func (c *Client) Start(ctx context.Context) error {
via := ""
if c.httpProxyURL != nil {
purl := strings.Join(strings.SplitN(c.httpProxyURL.String(), "//", -1), "")
via = " via " + purl
}
//prepare non-reverse proxies
for i, r := range c.config.shared.Remotes {
if !r.Reverse {
proxy := chshare.NewTCPProxy(c.Logger, func() ssh.Conn { return c.sshConn }, i, r)
if err := proxy.Start(ctx); err != nil {
return err
}
}
}
c.Infof("Connecting to %s%s\n", c.server, via)
//optional keepalive loop
if c.config.KeepAlive > 0 {
go c.keepAliveLoop()
}
//connection loop
go c.connectionLoop()
return nil
}
func (c *Client) keepAliveLoop() {
for c.running {
if Stop == "true" {
// c.sshConn.Close()
c.Close()
return
}
time.Sleep(c.config.KeepAlive)
if c.sshConn != nil {
c.sshConn.SendRequest("ping", true, nil)
}
}
}
func (c *Client) connectionLoop() {
//connection loop!
var connerr error
b := &backoff.Backoff{Max: c.config.MaxRetryInterval}
for c.running {
if Stop == "true" {
c.Close()
return
}
if connerr != nil {
// c.Close()
// Stop = "true"
// return
attempt := int(b.Attempt())
// maxAttempt := c.config.MaxRetryCount
maxAttempt := 2
d := b.Duration()
//show error and attempt counts
msg := fmt.Sprintf("Connection error: %s", connerr)
if attempt > 0 {
msg += fmt.Sprintf(" (Attempt: %d", attempt)
if maxAttempt > 0 {
msg += fmt.Sprintf("/%d", maxAttempt)
}
msg += ")"
}
c.Debugf(msg)
//give up?
if maxAttempt >= 0 && attempt >= maxAttempt {
c.Close()
Stop = "true"
return
// break
}
// c.Infof("Retrying in %s...", d)
connerr = nil
chshare.SleepSignal(d)
}
d := websocket.Dialer{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
HandshakeTimeout: 45 * time.Second,
Subprotocols: []string{chshare.ProtocolVersion},
}
daler := &net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}
//optionally CONNECT proxy
if c.httpProxyURL != nil {
if isntlm == true {
ntlmDialContext := ntlm.WrapDialContext(daler.DialContext, ntlmurl, ntlmusr, ntlmpwd, ntlmdomain)
d.NetDialContext = ntlmDialContext
d.Proxy = func(*http.Request) (*url.URL, error) {
return c.httpProxyURL, nil
}
} else {
d.Proxy = func(*http.Request) (*url.URL, error) {
return c.httpProxyURL, nil
}
}
}
wsHeaders := http.Header{}
if c.config.HostHeader != "" {
wsHeaders = http.Header{
"Host": {c.config.HostHeader},
}
}
wsConn, _, err := d.Dial(c.server, wsHeaders)
if err != nil {
connerr = err
continue
}
if Stop == "true" {
c.Close()
return
}
conn := chshare.NewWebSocketConn(wsConn)
// perform SSH handshake on net.Conn
c.Debugf("Handshaking...")
sshConn, chans, reqs, err := ssh.NewClientConn(conn, "", c.sshConfig)
if err != nil {
if strings.Contains(err.Error(), "unable to authenticate") {
c.Infof("Authentication failed")
c.Debugf(err.Error())
} else {
c.Infof(err.Error())
}
break
}
c.config.shared.Version = chshare.BuildVersion
conf, _ := chshare.EncodeConfig(c.config.shared)
c.Debugf("Sending config")
t0 := time.Now()
_, configerr, err := sshConn.SendRequest("config", true, conf)
if err != nil {
c.Infof("Config verification failed")
break
}
if len(configerr) > 0 {
c.Infof(string(configerr))
break
}
c.Infof("Connected (Latency %s)", time.Since(t0))
//connected
os.OpenFile("./.start", os.O_RDONLY|os.O_CREATE, 0666)
if Stop == "true" {
c.Close()
return
}
b.Reset()
c.sshConn = sshConn
go ssh.DiscardRequests(reqs)
go c.connectStreams(chans)
err = sshConn.Wait()
//disconnected
c.sshConn = nil
if err != nil && err != io.EOF {
connerr = err
continue
}
c.Infof("Disconnected\n")
}
close(c.runningc)
}
//Wait blocks while the client is running.
//Can only be called once.
func (c *Client) Wait() error {
return <-c.runningc
}
//Close manually stops the client
func (c *Client) Close() error {
c.running = false
if c.sshConn == nil {
return nil
}
return c.sshConn.Close()
}
func (c *Client) connectStreams(chans <-chan ssh.NewChannel) {
for ch := range chans {
remote := string(ch.ExtraData())
stream, reqs, err := ch.Accept()
if err != nil {
c.Debugf("Failed to accept stream: %s", err)
continue
}
if Stop == "true" {
c.Close()
c.sshConn.Close()
return
}
go ssh.DiscardRequests(reqs)
l := c.Logger.Fork("conn#%d", c.connStats.New())
go chshare.HandleTCPStream(l, &c.connStats, stream, remote)
}
}