Files
sing-box/dns/transport/base.go
2025-12-30 18:24:33 +08:00

146 lines
2.6 KiB
Go

package transport
import (
"context"
"os"
"sync"
C "github.com/sagernet/sing-box/constant"
"github.com/sagernet/sing-box/dns"
E "github.com/sagernet/sing/common/exceptions"
"github.com/sagernet/sing/common/logger"
)
type TransportState int
const (
StateNew TransportState = iota
StateStarted
StateClosing
StateClosed
)
var (
ErrTransportClosed = os.ErrClosed
ErrConnectionReset = E.New("connection reset")
)
type BaseTransport struct {
dns.TransportAdapter
Logger logger.ContextLogger
mutex sync.Mutex
state TransportState
inFlight int32
queriesComplete chan struct{}
closeCtx context.Context
closeCancel context.CancelFunc
}
func NewBaseTransport(adapter dns.TransportAdapter, logger logger.ContextLogger) *BaseTransport {
ctx, cancel := context.WithCancel(context.Background())
return &BaseTransport{
TransportAdapter: adapter,
Logger: logger,
state: StateNew,
closeCtx: ctx,
closeCancel: cancel,
}
}
func (t *BaseTransport) State() TransportState {
t.mutex.Lock()
defer t.mutex.Unlock()
return t.state
}
func (t *BaseTransport) SetStarted() error {
t.mutex.Lock()
defer t.mutex.Unlock()
switch t.state {
case StateNew:
t.state = StateStarted
return nil
case StateStarted:
return nil
default:
return ErrTransportClosed
}
}
func (t *BaseTransport) BeginQuery() bool {
t.mutex.Lock()
defer t.mutex.Unlock()
if t.state != StateStarted {
return false
}
t.inFlight++
return true
}
func (t *BaseTransport) EndQuery() {
t.mutex.Lock()
if t.inFlight > 0 {
t.inFlight--
}
if t.inFlight == 0 && t.queriesComplete != nil {
close(t.queriesComplete)
t.queriesComplete = nil
}
t.mutex.Unlock()
}
func (t *BaseTransport) CloseContext() context.Context {
return t.closeCtx
}
func (t *BaseTransport) Shutdown(ctx context.Context) error {
t.mutex.Lock()
if t.state >= StateClosing {
t.mutex.Unlock()
return nil
}
if t.state == StateNew {
t.state = StateClosed
t.mutex.Unlock()
t.closeCancel()
return nil
}
t.state = StateClosing
if t.inFlight == 0 {
t.state = StateClosed
t.mutex.Unlock()
t.closeCancel()
return nil
}
t.queriesComplete = make(chan struct{})
queriesComplete := t.queriesComplete
t.mutex.Unlock()
t.closeCancel()
select {
case <-queriesComplete:
t.mutex.Lock()
t.state = StateClosed
t.mutex.Unlock()
return nil
case <-ctx.Done():
t.mutex.Lock()
t.state = StateClosed
t.mutex.Unlock()
return ctx.Err()
}
}
func (t *BaseTransport) Close() error {
ctx, cancel := context.WithTimeout(context.Background(), C.TCPTimeout)
defer cancel()
return t.Shutdown(ctx)
}