Method handleTCPConnection

proxy/servertcp.go:126–166

handleTCPConnection starts a loop that handles an incoming TCP connection. proto must be either [ProtoTCP] or [ProtoTLS].

(
	ctx context.Context,
	conn net.Conn,
	proto Proto,
	reqSema syncutil.Semaphore,
)

// handleTCPConnection starts a loop that handles an incoming TCP connection.
// proto must be either [ProtoTCP] or [ProtoTLS].
func (p *Proxy) handleTCPConnection(
	ctx context.Context,
	conn net.Conn,
	proto Proto,
	reqSema syncutil.Semaphore,
) {
	defer slogutil.RecoverAndLog(ctx, p.logger)
	defer reqSema.Release()
	defer func() {
		err := conn.Close()
		if err != nil {
			logWithNonCrit(ctx, err, "closing conn", ProtoTCP, p.logger)
		}
	}()

	p.logger.DebugContext(ctx, "handling new request", "proto", proto, "raddr", conn.RemoteAddr())

	ctx, cancel := p.reqCtx.New(ctx)
	defer cancel()

	for p.isStarted() {
		err := conn.SetDeadline(p.time.Now().Add(defaultTimeout))
		if err != nil {
			// Consider deadline errors non-critical.
			logWithNonCrit(ctx, err, "setting deadline", ProtoTCP, p.logger)
		}

		req := p.readDNSReq(ctx, conn)
		if req == nil {
			return
		}

		d := p.newDNSContext(proto, req, netutil.NetAddrToAddrPort(conn.RemoteAddr()))
		d.Conn = conn

		err = p.handleDNSRequest(ctx, d)
		if err != nil {
			logWithNonCrit(ctx, err, "handling request", ProtoTCP, p.logger)
		}
	}
}

// readDNSReq returns DNS request message from the given connection or nil if
// it failed to read it.  Properly logs the error if it happened.