# RDMA (SMB Direct) Feature - Detailed Design Document

## 1. Overview

SMB Direct enables high-performance data transfer using Remote Direct Memory Access (RDMA) technology. This provides ultra-low latency and high bandwidth data transfer by bypassing the traditional TCP/IP stack and allowing direct memory-to-memory transfers between client and server.

## 2. Protocol Specification Reference

- **MS-SMBD**: SMB2 Remote Direct Memory Access (RDMA) Transport Protocol

     * @param isDirect whether to use direct transmission
     * @throws IOException if an I/O error occurs
     */
    protected abstract void doSendFragment(byte[] buf, int off, int length, boolean isDirect) throws IOException;

    /**
     * Receives a DCERPC fragment from the remote endpoint
     * @param buf the buffer to receive the fragment
     * @param isDirect whether to use direct reception

    protected long getBufferAddress(ByteBuffer buffer) {
        // In real implementation, this would get the native memory address:
        // For direct ByteBuffers, this could be obtained through unsafe operations
        // or DiSNI-specific methods

        if (buffer.isDirect()) {
            // Assign a unique address to each buffer instance

When we run this code, the interceptor runs twice. Once for the initial request to `http://www.publicobject.com/helloworld.txt`, and another for the redirect to `https://publicobject.com/helloworld.txt`.

```
INFO: Sending request http://www.publicobject.com/helloworld.txt on Connection{www.publicobject.com:80, proxy=DIRECT hostAddress=54.187.32.157 cipherSuite=none protocol=http/1.1}
User-Agent: OkHttp Example
Host: www.publicobject.com
Connection: Keep-Alive

IS'' AND ANY EXPRESS // OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE // ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR // BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,...

delete_cleanup_interval         (duration)  set to change intervals when deleted objects are permanently deleted from ".trash" folder (default: '5m')
odirect                         (boolean)   set to enable or disable O_DIRECT for writes under special conditions. NOTE: do not disable O_DIRECT without prior testing (default: 'on')

        assertNotNull(buffer, "Buffer should not be null");
        assertTrue(buffer.capacity() >= 2048, "Buffer should be at least requested size");
        assertTrue(buffer.isDirect(), "Buffer should be direct");
    }

    @Test
    public void testReleaseBuffer() {
        ByteBuffer buffer = bufferManager.allocateBuffer(1024);

        // Release should not throw exception

		if !guessIsHealthCheckReq(r) && guessIsBrowserReq(r) && read && globalBrowserRedirect {
			// Fetch the redirect location if any.
			if u := getRedirectLocation(r); u != nil {
				// Employ a temporary re-direct.
				http.Redirect(w, r, u.String(), http.StatusTemporaryRedirect)
				return
			}
		}
		h.ServeHTTP(w, r)
	})
}

var redirectPrefixes = map[string]struct{}{

 * this class separates _allocations_ from _streams_. An allocation is created by a call, used for
 * one or more streams, and then released. An allocated connection won't be stolen by other calls
 * while a redirect or authorization challenge is being handled.
 *
 * When the maximum concurrent streams limit is reduced, some allocations will be rescinded.
 * Attempting to create new streams on these allocations will fail.
 *

IS'' AND ANY EXPRESS // OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE // ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR // BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,...