const (
	Active	ConnState	= iota
	Open
	Closed
)

var log = logger.Get().WithField("prefix", "tcp-proxy")

This type doesn't have documentation.

Field name	Field type	Comment
type	uint	No comment on field.

type ConnState uint

Modifier define rules for tranforming incoming and outcoming TCP messages To filter response set data to empty To close connection, return error

Field name	Field type	Comment
ModifyRequest	func(src, dst net.Conn, data []byte) ([]byte, error)	No comment on field.
ModifyResponse	func(src, dst net.Conn, data []byte) ([]byte, error)	No comment on field.

type Modifier struct {
	ModifyRequest	func(src, dst net.Conn, data []byte) ([]byte, error)
	ModifyResponse	func(src, dst net.Conn, data []byte) ([]byte, error)
}

This type doesn't have documentation.

Field name	Field type	Comment
	sync.RWMutex	No comment on field.
DialTLS	func(network, addr string) (net.Conn, error)	No comment on field.
Dial	func(network, addr string) (net.Conn, error)	No comment on field.
TLSConfigTarget	*tls.Config	No comment on field.
ReadTimeout	time.Duration	No comment on field.
WriteTimeout	time.Duration	No comment on field.
muxer	map[string]*targetConfig	Domain to config mapping
SyncStats	func(Stat)	No comment on field.
StatsSyncInterval	time.Duration	Duration in which connection stats will be flushed. Defaults to one second.

type Proxy struct {
	sync.RWMutex

	DialTLS		func(network, addr string) (net.Conn, error)
	Dial		func(network, addr string) (net.Conn, error)
	TLSConfigTarget	*tls.Config

	ReadTimeout	time.Duration
	WriteTimeout	time.Duration

	// Domain to config mapping
	muxer		map[string]*targetConfig
	SyncStats	func(Stat)
	// Duration in which connection stats will be flushed. Defaults to one second.
	StatsSyncInterval	time.Duration
}

Stat defines basic statistics about a tcp connection

Field name	Field type	Comment
State	ConnState	No comment on field.
BytesIn	int64	No comment on field.
BytesOut	int64	No comment on field.

type Stat struct {
	State		ConnState
	BytesIn		int64
	BytesOut	int64
}

This type doesn't have documentation.

Field name	Field type	Comment
modifier	func(net.Conn, net.Conn, []byte) ([]byte, error)	No comment on field.
onReadError	func(error)	No comment on field.
onWriteError	func(error)	No comment on field.
beforeExit	func()	No comment on field.

type pipeOpts struct {
	modifier	func(net.Conn, net.Conn, []byte) ([]byte, error)
	onReadError	func(error)
	onWriteError	func(error)
	beforeExit	func()
}

This type doesn't have documentation.

Field name	Field type	Comment
modifier	*Modifier	No comment on field.
target	string	No comment on field.

type targetConfig struct {
	modifier	*Modifier
	target		string
}

IsSocketClosed returns true if err is a result of reading from closed network connection

func IsSocketClosed(err error) bool {
	return strings.Contains(err.Error(), "use of closed network connection")
}

Cognitive complexity: 0, Cyclomatic complexity: 1

Uses: strings.Contains.

func (p *Proxy) AddDomainHandler(domain, target string, modifier *Modifier) {
	p.Lock()
	defer p.Unlock()

	if p.muxer == nil {
		p.muxer = make(map[string]*targetConfig)
	}

	if modifier == nil {
		modifier = &Modifier{}
	}

	p.muxer[domain] = &targetConfig{
		modifier:	modifier,
		target:		target,
	}
}

Cognitive complexity: 6, Cyclomatic complexity: 3

func (p *Proxy) RemoveDomainHandler(domain string) {
	p.Lock()
	defer p.Unlock()

	delete(p.muxer, domain)
}

Cognitive complexity: 0, Cyclomatic complexity: 1

func (p *Proxy) Serve(l net.Listener) error {
	for {
		conn, err := l.Accept()
		if err != nil {
			log.WithError(err).Warning("Can't accept connection")
			return err
		}
		go func() {
			if err := p.handleConn(conn); err != nil {
				log.WithError(err).Warning("Can't handle connection")
			}
		}()
	}
}

Cognitive complexity: 7, Cyclomatic complexity: 4

func (p *Proxy) Swap(new *Proxy) {
	p.Lock()
	defer p.Unlock()

	p.muxer = new.muxer
	p.TLSConfigTarget = new.TLSConfigTarget
}

Cognitive complexity: 0, Cyclomatic complexity: 1

func (s *Stat) Flush() Stat {
	v := Stat{
		BytesIn:	atomic.LoadInt64(&s.BytesIn),
		BytesOut:	atomic.LoadInt64(&s.BytesOut),
	}
	atomic.StoreInt64(&s.BytesIn, 0)
	atomic.StoreInt64(&s.BytesOut, 0)
	return v
}

Cognitive complexity: 1, Cyclomatic complexity: 1

Uses: atomic.LoadInt64, atomic.StoreInt64.

clientConn (c net.Conn) string

formatAddress (a,b net.Addr) string

upstreamConn (c net.Conn) string

getTargetConfig (conn net.Conn) (*targetConfig, error)

handleConn (conn net.Conn) error

pipe (src,dst net.Conn, opts pipeOpts)