78 lines
3.1 KiB
Swift
78 lines
3.1 KiB
Swift
//
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// File.swift
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// sdlan
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//
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// Created by 安礼成 on 2025/7/14.
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//
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import Foundation
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import NIOCore
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// 网络类型探测器
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@available(macOS 14, *)
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struct SDLNatProber {
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// 定义nat类型
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enum NatType: UInt8, Encodable {
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case blocked = 0
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case noNat = 1
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case fullCone = 2
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case portRestricted = 3
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case coneRestricted = 4
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case symmetric = 5
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}
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// 获取当前所处的网络的nat类型
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static func getNatType(udpHole: SDLUDPHole?, config: SDLConfiguration, logger: SDLLogger) async -> NatType {
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guard let udpHole else {
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return .blocked
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}
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let addressArray = config.stunProbeSocketAddressArray
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// step1: ip1:port1 <---- ip1:port1
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guard let natAddress1 = await getNatAddress(udpHole, remoteAddress: addressArray[0][0], attr: .none) else {
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return .blocked
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}
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// 网络没有在nat下
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if await natAddress1 == udpHole.localAddress {
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return .noNat
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}
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// step2: ip2:port2 <---- ip2:port2
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guard let natAddress2 = await getNatAddress(udpHole, remoteAddress: addressArray[1][1], attr: .none) else {
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return .blocked
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}
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// 如果natAddress2 的IP地址与上次回来的IP是不一样的，它就是对称型NAT; 这次的包也一定能发成功并收到
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// 如果ip地址变了，这说明{dstIp, dstPort, srcIp, srcPort}, 其中有一个变了；则用新的ip地址
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logger.log("[SDLNatProber] nat_address1: \(natAddress1), nat_address2: \(natAddress2)", level: .debug)
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if let ipAddress1 = natAddress1.ipAddress, let ipAddress2 = natAddress2.ipAddress, ipAddress1 != ipAddress2 {
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return .symmetric
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}
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// step3: ip1:port1 <---- ip2:port2 (ip地址和port都变的情况)
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// 如果能收到的，说明是完全锥形 说明是IP地址限制锥型NAT，如果不能收到说明是端口限制锥型。
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if let natAddress3 = await getNatAddress(udpHole, remoteAddress: addressArray[0][0], attr: .peer) {
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logger.log("[SDLNatProber] nat_address1: \(natAddress1), nat_address2: \(natAddress2), nat_address3: \(natAddress3)", level: .debug)
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return .fullCone
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}
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// step3: ip1:port1 <---- ip1:port2 (port改变情况)
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// 如果能收到的说明是IP地址限制锥型NAT，如果不能收到说明是端口限制锥型。
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if let natAddress4 = await getNatAddress(udpHole, remoteAddress: addressArray[0][0], attr: .port) {
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logger.log("[SDLNatProber] nat_address1: \(natAddress1), nat_address2: \(natAddress2), nat_address4: \(natAddress4)", level: .debug)
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return .coneRestricted
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} else {
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return .portRestricted
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}
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}
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private static func getNatAddress(_ udpHole: SDLUDPHole, remoteAddress: SocketAddress, attr: SDLProbeAttr) async -> SocketAddress? {
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let stunProbeReply = try? await udpHole.stunProbe(remoteAddress: remoteAddress, attr: attr, timeout: 5)
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return stunProbeReply?.socketAddress()
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}
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}
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