frp/pkg/nathole/classify.go

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2023-03-30 14:28:15 +02:00
// Copyright 2023 The frp Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package nathole
import (
"fmt"
"net"
)
const (
EasyNAT = "EasyNAT"
HardNAT = "HardNAT"
BehaviorNoChange = "BehaviorNoChange"
BehaviorIPChanged = "BehaviorIPChanged"
BehaviorPortChanged = "BehaviorPortChanged"
BehaviorBothChanged = "BehaviorBothChanged"
)
// ClassifyNATType classify NAT type by given addresses.
func ClassifyNATType(addresses []string) (string, string, error) {
if len(addresses) <= 1 {
return "", "", fmt.Errorf("not enough addresses")
}
ipChanged := false
portChanged := false
var baseIP, basePort string
for _, addr := range addresses {
ip, port, err := net.SplitHostPort(addr)
if err != nil {
return "", "", err
}
if baseIP == "" {
baseIP = ip
basePort = port
continue
}
if baseIP != ip {
ipChanged = true
}
if basePort != port {
portChanged = true
}
if ipChanged && portChanged {
break
}
}
switch {
case ipChanged && portChanged:
return HardNAT, BehaviorBothChanged, nil
case ipChanged:
return HardNAT, BehaviorIPChanged, nil
case portChanged:
return HardNAT, BehaviorPortChanged, nil
default:
return EasyNAT, BehaviorNoChange, nil
}
}