feat(正式发布): 以Apache License 2.0协议开源

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2026-01-22 14:36:46 +08:00
parent b11b3e617c
commit 66d61df266
9 changed files with 846 additions and 1 deletions
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// Copyright 2026 肖其顿 (XIAO QI DUN)
//
// 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 main
import (
"crypto/rand"
"net"
"strconv"
"time"
)
// MappingEndpointIndependent 独立映射模式常量
const MappingEndpointIndependent = "Endpoint-Independent"
// MappingAddressDependent 地址相关映射模式常量
const MappingAddressDependent = "Address-Dependent"
// MappingAddressPortDependent 地址端口相关映射模式常量
const MappingAddressPortDependent = "Address and Port-Dependent"
// MappingUnknown 未知映射模式常量
const MappingUnknown = "Unknown"
// FilteringEndpointIndependent 独立过滤模式常量
const FilteringEndpointIndependent = "Endpoint-Independent"
// FilteringAddressDependent 地址相关过滤模式常量
const FilteringAddressDependent = "Address-Dependent"
// FilteringAddressPortDependent 地址端口相关过滤模式常量
const FilteringAddressPortDependent = "Address and Port-Dependent"
// FilteringUnknown 未知过滤模式常量
const FilteringUnknown = "Unknown"
// NATOpen 公网类型常量
const NATOpen = "Open Internet"
// NATFullCone 全锥型NAT常量
const NATFullCone = "Full Cone"
// NATRestricted 限制锥型NAT常量
const NATRestricted = "Restricted Cone"
// NATPortRestricted 端口限制锥型NAT常量
const NATPortRestricted = "Port Restricted Cone"
// NATSymmetric 对称型NAT常量
const NATSymmetric = "Symmetric"
// NATUDPBlocked UDP阻塞常量
const NATUDPBlocked = "UDP Blocked"
// NATUnknown 未知类型常量
const NATUnknown = "Unknown"
// NATResult NAT探测结果结构
type NATResult struct {
Type string
Mapping string
Filtering string
MappedIP string
}
// resolveAddr 解析探测目标地址
// 入参: conn 当前连接, addrStr 目标地址字符串, network 网络协议
// 返回: addr 解析后的网络地址, err 解析错误
func resolveAddr(conn net.PacketConn, addrStr, network string) (net.Addr, error) {
host, portStr, err := net.SplitHostPort(addrStr)
if err != nil {
return nil, err
}
port, err := strconv.Atoi(portStr)
if err != nil {
return nil, err
}
if _, ok := conn.(*socks5PacketConn); ok {
if net.ParseIP(host) == nil && host != "localhost" && host != "127.0.0.1" {
return &SocksAddr{Host: host, Port: port}, nil
}
}
return net.ResolveUDPAddr(network, addrStr)
}
// performTest 执行单次STUN探测
// 入参: conn 连接对象, serverAddr STUN服务器地址, network 协议, timeout 超时设定, changeIP 变更IP标志, changePort 变更端口标志
// 返回: msg 响应消息, addr 响应源地址, err 探测错误
func performTest(conn net.PacketConn, serverAddr string, network string, timeout time.Duration, changeIP, changePort bool) (*stunMessage, *net.UDPAddr, error) {
dst, err := resolveAddr(conn, serverAddr, network)
if err != nil {
return nil, nil, err
}
txID := [12]byte{}
rand.Read(txID[:])
req := encodeSTUNRequest(txID, changeIP, changePort)
if _, err := conn.WriteTo(req, dst); err != nil {
return nil, nil, err
}
conn.SetReadDeadline(time.Now().Add(timeout))
defer conn.SetReadDeadline(time.Time{})
buf := make([]byte, 2048)
for i := 0; i < 3; i++ {
n, addr, err := conn.ReadFrom(buf)
if err != nil {
if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
break
}
return nil, nil, err
}
msg, err := decodeSTUNResponse(buf[:n], txID)
if err != nil {
continue
}
uAddr, ok := addr.(*net.UDPAddr)
if !ok {
continue
}
return msg, uAddr, nil
}
return nil, nil, nil
}
// DetectNAT 执行NAT类型检测核心逻辑
// 入参: conn 连接对象, primarySTUN 主服务器, secondarySTUN 辅服务器, network 协议, timeout 超时设定
// 返回: result 检测结果
func DetectNAT(conn net.PacketConn, primarySTUN, secondarySTUN, network string, timeout time.Duration) NATResult {
res := NATResult{Type: NATUnknown, Mapping: MappingUnknown, Filtering: FilteringUnknown}
resp1, _, err := performTest(conn, primarySTUN, network, timeout, false, false)
if err != nil || resp1 == nil {
res.Type = NATUDPBlocked
return res
}
mappedAddr1 := resp1.GetMappedAddress()
if mappedAddr1 == nil {
return res
}
res.MappedIP = mappedAddr1.String()
var targetSTUN2 string
if secondarySTUN != "" {
targetSTUN2 = secondarySTUN
} else {
changedAddr := resp1.GetChangedAddress()
if changedAddr != nil {
targetSTUN2 = net.JoinHostPort(changedAddr.IP.String(), strconv.Itoa(changedAddr.Port))
} else {
host, port, _ := net.SplitHostPort(primarySTUN)
ips, err := net.LookupIP(host)
if err == nil && len(ips) > 1 {
primaryIP, _ := net.ResolveIPAddr("ip", host)
wantIPv4 := network == "udp4"
wantIPv6 := network == "udp6"
if network == "udp" {
wantIPv4 = primaryIP.IP.To4() != nil
wantIPv6 = !wantIPv4
}
for _, ip := range ips {
if ip.Equal(primaryIP.IP) {
continue
}
isV4 := ip.To4() != nil
if wantIPv4 && !isV4 {
continue
}
if wantIPv6 && isV4 {
continue
}
targetSTUN2 = net.JoinHostPort(ip.String(), port)
break
}
}
}
}
var mappedAddr3 *net.UDPAddr
if targetSTUN2 != "" {
resp3, _, err := performTest(conn, targetSTUN2, network, timeout, false, false)
if err == nil && resp3 != nil {
mappedAddr3 = resp3.GetMappedAddress()
}
}
if mappedAddr3 != nil {
if mappedAddr1.String() == mappedAddr3.String() {
res.Mapping = MappingEndpointIndependent
} else {
res.Mapping = MappingAddressPortDependent
}
} else {
res.Mapping = MappingUnknown
}
resp2, _, _ := performTest(conn, primarySTUN, network, timeout, true, true)
if resp2 != nil {
res.Filtering = FilteringEndpointIndependent
} else {
resp4, _, _ := performTest(conn, primarySTUN, network, timeout, false, true)
if resp4 != nil {
res.Filtering = FilteringAddressDependent
} else {
res.Filtering = FilteringAddressPortDependent
}
}
if res.Filtering == FilteringEndpointIndependent {
res.Type = NATFullCone
if res.Mapping == MappingUnknown {
res.Mapping = MappingEndpointIndependent
}
} else if res.Mapping == MappingEndpointIndependent {
switch res.Filtering {
case FilteringAddressDependent:
res.Type = NATRestricted
case FilteringAddressPortDependent:
res.Type = NATPortRestricted
}
} else {
res.Type = NATSymmetric
}
return res
}