105 lines
3.6 KiB
C#
105 lines
3.6 KiB
C#
using System.Globalization;
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using System.Net;
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namespace MoShiro.Protocol;
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/// <summary>
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/// 单个 Agent 任务的目标：<c>http</c> 是 <c>http(s)://主机[:端口][/路径]</c>，其余 Kind 是 <c>主机[:端口]</c>（IP 或域名，IPv6 带端口时用方括号）。
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/// Backend 只检查格式，不做 DNS 解析；解析在 Agent 上进行，每个解析出的地址都要在 <c>allowed_target_cidrs</c> 里。
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/// </summary>
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public static class TargetHost
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{
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public const string HttpKind = "http_request";
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/// <summary>解析目标；<paramref name="port"/> 为 0 表示没有写端口，<paramref name="url"/> 只在 http(s) URL 时有值。</summary>
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public static bool TryParse(string? target, out string host, out int port, out Uri? url)
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{
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host = "";
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port = 0;
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url = null;
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if (string.IsNullOrWhiteSpace(target) || target.Length > 2048 || target.Any(char.IsWhiteSpace))
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{
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return false;
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}
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if (target.Contains("://", StringComparison.Ordinal))
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{
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if (!Uri.TryCreate(target, UriKind.Absolute, out Uri? uri) || uri.Scheme is not ("http" or "https") || uri.UserInfo.Length > 0 || !ValidHost(uri.IdnHost))
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{
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return false;
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}
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url = uri;
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host = uri.IdnHost.Trim('[', ']');
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port = uri.IsDefaultPort ? 0 : uri.Port;
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return true;
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}
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// IPAddress.TryParse 会把「[v6]:端口」的端口丢掉，带方括号的先按端点解析
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if (!target.StartsWith('[') && IPAddress.TryParse(target, out IPAddress? ip))
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{
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host = ip.ToString();
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return true;
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}
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if (IPEndPoint.TryParse(target, out IPEndPoint? endpoint))
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{
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if (endpoint.Port is 0)
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{
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return false;
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}
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host = endpoint.Address.ToString();
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port = endpoint.Port;
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return true;
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}
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int colon = target.LastIndexOf(':');
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string name = colon < 0 ? target : target[..colon];
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if (colon >= 0 && (!int.TryParse(target.AsSpan(colon + 1), NumberStyles.None, CultureInfo.InvariantCulture, out port) || port is < 1 or > 65535))
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{
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return false;
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}
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if (!ValidHost(name))
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{
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return false;
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}
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host = name.ToLowerInvariant();
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return true;
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}
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/// <summary>按 Kind 检查并规范化：<c>http</c> 必须是 http(s) URL，其余 Kind 必须是主机[:端口]；不合格返回 null。</summary>
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public static string? Normalize(string kindId, string? target)
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{
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if (!TryParse(target, out string host, out int port, out Uri? url) || (url is not null) != (kindId == HttpKind))
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{
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return null;
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}
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if (url is not null)
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{
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return url.AbsoluteUri;
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}
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string shown = IPAddress.TryParse(host, out IPAddress? ip) && ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetworkV6 && port != 0 ? "[" + host + "]" : host;
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return port == 0 ? host : shown + ":" + port.ToString(CultureInfo.InvariantCulture);
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}
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private static bool ValidHost(string name)
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{
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if (IPAddress.TryParse(name.Trim('[', ']'), out _))
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{
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return true;
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}
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if (name.Length is 0 or > 253 || name[^1] == '-' || name[0] is '-' or '.')
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{
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return false;
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}
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return name.TrimEnd('.').Split('.').All(label => label.Length is > 0 and <= 63 && label.All(c => char.IsAsciiLetterOrDigit(c) || c == '-'));
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}
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}
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