422 lines
8.0 KiB
Go
422 lines
8.0 KiB
Go
package tun2
|
|
|
|
import (
|
|
"context"
|
|
"crypto/tls"
|
|
"encoding/json"
|
|
"errors"
|
|
"math/rand"
|
|
"net"
|
|
"net/http"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/Xe/ln"
|
|
failure "github.com/dgryski/go-failure"
|
|
"github.com/mtneug/pkg/ulid"
|
|
cmap "github.com/streamrail/concurrent-map"
|
|
kcp "github.com/xtaci/kcp-go"
|
|
"github.com/xtaci/smux"
|
|
)
|
|
|
|
// Error values
|
|
var (
|
|
ErrNoSuchBackend = errors.New("tun2: there is no such backend")
|
|
ErrAuthMismatch = errors.New("tun2: authenication doesn't match database records")
|
|
ErrCantRemoveWhatDoesntExist = errors.New("tun2: this connection does not exist, cannot remove it")
|
|
)
|
|
|
|
// ServerConfig ...
|
|
type ServerConfig struct {
|
|
TCPAddr string
|
|
KCPAddr string
|
|
TLSConfig *tls.Config
|
|
|
|
SmuxConf *smux.Config
|
|
Storage Storage
|
|
}
|
|
|
|
// Storage is the minimal subset of features that tun2's Server needs out of a
|
|
// persistence layer.
|
|
type Storage interface {
|
|
HasToken(token string) (user string, scopes []string, err error)
|
|
HasRoute(domain string) (user string, err error)
|
|
}
|
|
|
|
// Server routes frontend HTTP traffic to backend TCP traffic.
|
|
type Server struct {
|
|
cfg *ServerConfig
|
|
|
|
connlock sync.Mutex
|
|
conns map[net.Conn]*Connection
|
|
|
|
domains cmap.ConcurrentMap
|
|
}
|
|
|
|
// NewServer creates a new Server instance with a given config, acquiring all
|
|
// relevant resources.
|
|
func NewServer(cfg *ServerConfig) (*Server, error) {
|
|
if cfg == nil {
|
|
return nil, errors.New("tun2: config must be specified")
|
|
}
|
|
|
|
if cfg.SmuxConf == nil {
|
|
cfg.SmuxConf = smux.DefaultConfig()
|
|
}
|
|
|
|
cfg.SmuxConf.KeepAliveInterval = time.Second
|
|
cfg.SmuxConf.KeepAliveTimeout = 15 * time.Second
|
|
|
|
server := &Server{
|
|
cfg: cfg,
|
|
|
|
conns: map[net.Conn]*Connection{},
|
|
domains: cmap.New(),
|
|
}
|
|
|
|
return server, nil
|
|
}
|
|
|
|
// ListenAndServe starts the backend TCP/KCP listeners and relays backend
|
|
// traffic to and from them.
|
|
func (s *Server) ListenAndServe() error {
|
|
ln.Log(ln.F{
|
|
"action": "listen_and_serve_called",
|
|
})
|
|
|
|
if s.cfg.TCPAddr != "" {
|
|
go func() {
|
|
l, err := tls.Listen("tcp", s.cfg.TCPAddr, s.cfg.TLSConfig)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
ln.Log(ln.F{
|
|
"action": "tcp+tls_listening",
|
|
"addr": l.Addr(),
|
|
})
|
|
|
|
for {
|
|
conn, err := l.Accept()
|
|
if err != nil {
|
|
ln.Error(err, ln.F{"kind": "tcp", "addr": l.Addr().String()})
|
|
continue
|
|
}
|
|
|
|
ln.Log(ln.F{
|
|
"action": "new_client",
|
|
"kcp": false,
|
|
"addr": conn.RemoteAddr(),
|
|
})
|
|
|
|
go s.HandleConn(conn, false)
|
|
}
|
|
}()
|
|
}
|
|
|
|
if s.cfg.KCPAddr != "" {
|
|
go func() {
|
|
l, err := kcp.Listen(s.cfg.KCPAddr)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
ln.Log(ln.F{
|
|
"action": "kcp+tls_listening",
|
|
"addr": l.Addr(),
|
|
})
|
|
|
|
for {
|
|
conn, err := l.Accept()
|
|
if err != nil {
|
|
ln.Error(err, ln.F{"kind": "kcp", "addr": l.Addr().String()})
|
|
}
|
|
|
|
ln.Log(ln.F{
|
|
"action": "new_client",
|
|
"kcp": true,
|
|
"addr": conn.RemoteAddr(),
|
|
})
|
|
|
|
tc := tls.Server(conn, s.cfg.TLSConfig)
|
|
|
|
go s.HandleConn(tc, true)
|
|
}
|
|
}()
|
|
}
|
|
|
|
// XXX experimental, might get rid of this inside this process
|
|
go func() {
|
|
for {
|
|
time.Sleep(time.Second)
|
|
|
|
now := time.Now()
|
|
|
|
s.connlock.Lock()
|
|
for _, c := range s.conns {
|
|
failureChance := c.detector.Phi(now)
|
|
|
|
if failureChance != 0 {
|
|
ln.Log(c.F(), ln.F{
|
|
"action": "phi_failure_detection",
|
|
"value": failureChance,
|
|
})
|
|
}
|
|
}
|
|
s.connlock.Unlock()
|
|
}
|
|
}()
|
|
|
|
return nil
|
|
}
|
|
|
|
// HandleConn starts up the needed mechanisms to relay HTTP traffic to/from
|
|
// the currently connected backend.
|
|
func (s *Server) HandleConn(c net.Conn, isKCP bool) {
|
|
// XXX TODO clean this up it's really ugly.
|
|
defer c.Close()
|
|
|
|
ctx, cancel := context.WithCancel(context.Background())
|
|
defer cancel()
|
|
|
|
session, err := smux.Server(c, s.cfg.SmuxConf)
|
|
if err != nil {
|
|
ln.Error(err, ln.F{
|
|
"action": "session_failure",
|
|
"local": c.LocalAddr().String(),
|
|
"remote": c.RemoteAddr().String(),
|
|
})
|
|
|
|
c.Close()
|
|
|
|
return
|
|
}
|
|
defer session.Close()
|
|
|
|
controlStream, err := session.OpenStream()
|
|
if err != nil {
|
|
ln.Error(err, ln.F{
|
|
"action": "control_stream_failure",
|
|
"local": c.LocalAddr().String(),
|
|
"remote": c.RemoteAddr().String(),
|
|
})
|
|
|
|
return
|
|
}
|
|
defer controlStream.Close()
|
|
|
|
csd := json.NewDecoder(controlStream)
|
|
auth := &Auth{}
|
|
err = csd.Decode(auth)
|
|
if err != nil {
|
|
ln.Error(err, ln.F{
|
|
"action": "control_stream_auth_decoding_failure",
|
|
"local": c.LocalAddr().String(),
|
|
"remote": c.RemoteAddr().String(),
|
|
})
|
|
|
|
return
|
|
}
|
|
|
|
routeUser, err := s.cfg.Storage.HasRoute(auth.Domain)
|
|
if err != nil {
|
|
ln.Error(err, ln.F{
|
|
"action": "nosuch_domain",
|
|
"local": c.LocalAddr().String(),
|
|
"remote": c.RemoteAddr().String(),
|
|
})
|
|
|
|
return
|
|
}
|
|
|
|
tokenUser, scopes, err := s.cfg.Storage.HasToken(auth.Token)
|
|
if err != nil {
|
|
ln.Error(err, ln.F{
|
|
"action": "nosuch_token",
|
|
"local": c.LocalAddr().String(),
|
|
"remote": c.RemoteAddr().String(),
|
|
})
|
|
|
|
return
|
|
}
|
|
|
|
ok := false
|
|
for _, sc := range scopes {
|
|
if sc == "connect" {
|
|
ok = true
|
|
break
|
|
}
|
|
}
|
|
|
|
if !ok {
|
|
ln.Error(ErrAuthMismatch, ln.F{
|
|
"action": "token_not_authorized",
|
|
"local": c.LocalAddr().String(),
|
|
"remote": c.RemoteAddr().String(),
|
|
})
|
|
}
|
|
|
|
if routeUser != tokenUser {
|
|
ln.Error(ErrAuthMismatch, ln.F{
|
|
"action": "auth_mismatch",
|
|
"local": c.LocalAddr().String(),
|
|
"remote": c.RemoteAddr().String(),
|
|
})
|
|
|
|
return
|
|
}
|
|
|
|
connection := &Connection{
|
|
id: ulid.New().String(),
|
|
conn: c,
|
|
isKCP: isKCP,
|
|
session: session,
|
|
user: tokenUser,
|
|
domain: auth.Domain,
|
|
cancel: cancel,
|
|
detector: failure.New(15, 1),
|
|
Auth: auth,
|
|
}
|
|
|
|
ln.Log(ln.F{
|
|
"action": "backend_connected",
|
|
}, connection.F())
|
|
|
|
s.connlock.Lock()
|
|
s.conns[c] = connection
|
|
s.connlock.Unlock()
|
|
|
|
var conns []*Connection
|
|
|
|
val, ok := s.domains.Get(auth.Domain)
|
|
if ok {
|
|
conns, ok = val.([]*Connection)
|
|
if !ok {
|
|
conns = nil
|
|
|
|
s.domains.Remove(auth.Domain)
|
|
}
|
|
}
|
|
|
|
conns = append(conns, connection)
|
|
|
|
s.domains.Set(auth.Domain, conns)
|
|
|
|
ticker := time.NewTicker(5 * time.Second)
|
|
defer ticker.Stop()
|
|
|
|
for {
|
|
select {
|
|
case <-ticker.C:
|
|
err := connection.Ping()
|
|
if err != nil {
|
|
cancel()
|
|
}
|
|
case <-ctx.Done():
|
|
s.RemoveConn(connection)
|
|
connection.Close()
|
|
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// RemoveConn removes a connection.
|
|
func (s *Server) RemoveConn(connection *Connection) {
|
|
s.connlock.Lock()
|
|
delete(s.conns, connection.conn)
|
|
s.connlock.Unlock()
|
|
|
|
auth := connection.Auth
|
|
|
|
var conns []*Connection
|
|
|
|
val, ok := s.domains.Get(auth.Domain)
|
|
if ok {
|
|
conns, ok = val.([]*Connection)
|
|
if !ok {
|
|
ln.Error(ErrCantRemoveWhatDoesntExist, connection.F(), ln.F{
|
|
"action": "looking_up_for_disconnect_removal",
|
|
})
|
|
return
|
|
}
|
|
}
|
|
|
|
for i, cntn := range conns {
|
|
if cntn.id == connection.id {
|
|
conns[i] = conns[len(conns)-1]
|
|
conns = conns[:len(conns)-1]
|
|
}
|
|
}
|
|
|
|
if len(conns) != 0 {
|
|
s.domains.Set(auth.Domain, conns)
|
|
} else {
|
|
s.domains.Remove(auth.Domain)
|
|
}
|
|
|
|
ln.Log(connection.F(), ln.F{
|
|
"action": "client_disconnecting",
|
|
})
|
|
}
|
|
|
|
// RoundTrip sends a HTTP request to a backend and then returns its response.
|
|
func (s *Server) RoundTrip(req *http.Request) (*http.Response, error) {
|
|
var conns []*Connection
|
|
|
|
val, ok := s.domains.Get(req.Host)
|
|
if ok {
|
|
conns, ok = val.([]*Connection)
|
|
if !ok {
|
|
ln.Error(ErrNoSuchBackend, ln.F{
|
|
"action": "no_backend_connected",
|
|
"remote": req.RemoteAddr,
|
|
"host": req.Host,
|
|
"uri": req.RequestURI,
|
|
})
|
|
|
|
return nil, ErrNoSuchBackend
|
|
}
|
|
}
|
|
|
|
if len(conns) == 0 {
|
|
ln.Error(ErrNoSuchBackend, ln.F{
|
|
"action": "no_backend_connected",
|
|
"remote": req.RemoteAddr,
|
|
"host": req.Host,
|
|
"uri": req.RequestURI,
|
|
})
|
|
|
|
return nil, ErrNoSuchBackend
|
|
}
|
|
|
|
c := conns[rand.Intn(len(conns))]
|
|
|
|
resp, err := c.RoundTrip(req)
|
|
if err != nil {
|
|
ln.Error(err, c.F(), ln.F{
|
|
"action": "connection_roundtrip",
|
|
})
|
|
|
|
defer c.cancel()
|
|
return nil, err
|
|
}
|
|
|
|
ln.Log(c.F(), ln.F{
|
|
"action": "http_traffic",
|
|
"remote_addr": req.RemoteAddr,
|
|
"host": req.Host,
|
|
"uri": req.RequestURI,
|
|
})
|
|
|
|
return resp, nil
|
|
}
|
|
|
|
// Auth is the authentication info the client passes to the server.
|
|
type Auth struct {
|
|
Token string `json:"token"`
|
|
Domain string `json:"domain"`
|
|
}
|
|
|
|
const defaultUser = "Cadey"
|