106 lines
3.0 KiB
Go
106 lines
3.0 KiB
Go
package checker
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"net"
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"time"
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"mtproxy_checker/internal/faketls"
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"mtproxy_checker/internal/mtproxy"
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"mtproxy_checker/internal/secret"
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)
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// ErrProxyClosed indicates the MTProxy dropped the TCP connection right after the probe (Telethon #1134 style).
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var ErrProxyClosed = errors.New("mtproxy closed connection after initial payload")
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// Check runs the handshake probe for the given parsed secret.
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func Check(ctx context.Context, host string, port int, parsed *secret.Parsed, dcID int16) error {
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conn, err := dialTCP(ctx, host, port)
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if err != nil {
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return fmt.Errorf("tcp dial: %w", err)
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}
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defer conn.Close()
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switch parsed.Kind {
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case secret.KindEE:
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return checkEE(conn, parsed, dcID)
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case secret.KindDD:
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return checkDD(conn, parsed, dcID)
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default:
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return fmt.Errorf("unknown secret kind")
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}
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}
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func checkEE(conn net.Conn, p *secret.Parsed, dcID int16) error {
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// ee-секрет хранит домен как «сырой» хвост (часто 0xd0 + ASCII hostname). В TLS SNI нужен только hostname,
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// как в официальном клиенте Telegram — иначе прокси сбрасывает соединение до ServerHello.
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sni := faketls.SNIDomain(p.Domain)
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if len(sni) == 0 {
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sni = p.Domain
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}
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ch, err := faketls.BuildTdesktopClientHello(p.Key, sni)
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if err != nil {
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return fmt.Errorf("fake-tls client hello: %w", err)
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}
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if _, err := conn.Write(ch.Record); err != nil {
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return fmt.Errorf("write client hello: %w", err)
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}
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resp, err := faketls.ReadServerHello(conn)
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if err != nil {
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return fmt.Errorf("read server hello: %w", err)
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}
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if err := faketls.VerifyServerHelloTdesktop(resp, p.Key, ch.RandomField); err != nil {
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return fmt.Errorf("verify server hello: %w", err)
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}
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hdr, _, _, err := mtproxy.InitHeader(p.Key, dcID)
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if err != nil {
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return fmt.Errorf("mtproxy header: %w", err)
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}
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if err := faketls.WriteTLSApplicationData(conn, hdr); err != nil {
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return fmt.Errorf("write mtproxy header: %w", err)
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}
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return waitPostPayload(conn)
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}
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func checkDD(conn net.Conn, p *secret.Parsed, dcID int16) error {
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hdr, _, _, err := mtproxy.InitHeader(p.Key, dcID)
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if err != nil {
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return fmt.Errorf("mtproxy header: %w", err)
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}
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if _, err := conn.Write(hdr); err != nil {
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return fmt.Errorf("write mtproxy header: %w", err)
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}
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return waitPostPayload(conn)
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}
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func waitPostPayload(conn net.Conn) error {
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deadline := time.Now().Add(2 * time.Second)
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buf := make([]byte, 4096)
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for time.Now().Before(deadline) {
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_ = conn.SetReadDeadline(time.Now().Add(200 * time.Millisecond))
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n, err := conn.Read(buf)
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if n > 0 {
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_ = conn.SetReadDeadline(time.Time{})
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return nil
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}
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if err != nil {
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if errors.Is(err, io.EOF) {
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_ = conn.SetReadDeadline(time.Time{})
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return ErrProxyClosed
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}
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var ne net.Error
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if errors.As(err, &ne) && ne.Timeout() {
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continue
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}
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_ = conn.SetReadDeadline(time.Time{})
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return err
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}
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}
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_ = conn.SetReadDeadline(time.Time{})
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return nil
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}
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