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Xray-core/common/drain/drainer.go

63 lines
1.5 KiB

package drain
import (
"io"
"github.com/xtls/xray-core/common/dice"
"github.com/xtls/xray-core/common/errors"
)
type BehaviorSeedLimitedDrainer struct {
DrainSize int
}
func NewBehaviorSeedLimitedDrainer(behaviorSeed int64, drainFoundation, maxBaseDrainSize, maxRandDrain int) (Drainer, error) {
behaviorRand := dice.NewDeterministicDice(behaviorSeed)
BaseDrainSize := behaviorRand.Roll(maxBaseDrainSize)
RandDrainMax := behaviorRand.Roll(maxRandDrain) + 1
RandDrainRolled := dice.Roll(RandDrainMax)
DrainSize := drainFoundation + BaseDrainSize + RandDrainRolled
return &BehaviorSeedLimitedDrainer{DrainSize: DrainSize}, nil
}
func (d *BehaviorSeedLimitedDrainer) AcknowledgeReceive(size int) {
d.DrainSize -= size
}
func (d *BehaviorSeedLimitedDrainer) Drain(reader io.Reader) error {
if d.DrainSize > 0 {
err := drainReadN(reader, d.DrainSize)
if err == nil {
return errors.New("drained connection")
}
return errors.New("unable to drain connection").Base(err)
}
return nil
}
func drainReadN(reader io.Reader, n int) error {
_, err := io.CopyN(io.Discard, reader, int64(n))
return err
}
func WithError(drainer Drainer, reader io.Reader, err error) error {
drainErr := drainer.Drain(reader)
if drainErr == nil {
return err
}
return errors.New(drainErr).Base(err)
}
type NopDrainer struct{}
func (n NopDrainer) AcknowledgeReceive(size int) {
}
func (n NopDrainer) Drain(reader io.Reader) error {
return nil
}
func NewNopDrainer() Drainer {
return &NopDrainer{}
}