fix: refactor processing of junk packets (#103)

- fix the bug that transport packet interprets as init/resp/cookie with the same size
- cleanup error responses
- reduce buffer allocations

device/peer.go

@@ -13,7 +13,6 @@ import (
 	"time"
 
 	"github.com/amnezia-vpn/amneziawg-go/conn"
-	"github.com/amnezia-vpn/amneziawg-go/device/awg"
 )
 
 type Peer struct {
@@ -114,16 +113,6 @@ func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
 	return peer, nil
 }
 
-func (peer *Peer) SendAndCountBuffers(buffers [][]byte) error {
-	err := peer.SendBuffers(buffers)
-	if err == nil {
-		awg.PacketCounter.Add(uint64(len(buffers)))
-		return nil
-	}
-
-	return err
-}
-
 func (peer *Peer) SendBuffers(buffers [][]byte) error {
 	peer.device.net.RLock()
 	defer peer.device.net.RUnlock()