diff --git a/fastbootd/transport.c b/fastbootd/transport.c
new file mode 100644
index 0000000..01a5a8a
--- /dev/null
+++ b/fastbootd/transport.c
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <pthread.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include "debug.h"
+#include "protocol.h"
+#include "transport.h"
+
+#define COMMAND_BUF_SIZE 64
+
+ssize_t transport_handle_write(struct transport_handle *thandle, char *buffer, size_t len)
+{
+    return thandle->transport->write(thandle, buffer, len);
+}
+
+void transport_handle_close(struct transport_handle *thandle)
+{
+    thandle->transport->close(thandle);
+}
+
+int transport_handle_download(struct transport_handle *thandle, size_t len)
+{
+    ssize_t ret;
+    size_t n = 0;
+    int fd;
+    // TODO: move out of /dev
+    char tempname[] = "/dev/fastboot_download_XXXXXX";
+    char *buffer;
+
+    fd = mkstemp(tempname);
+    if (fd < 0)
+        return -1;
+
+    unlink(tempname);
+
+    ftruncate(fd, len);
+
+    buffer = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+    if (buffer == NULL) {
+        D(ERR, "mmap(%u) failed: %d %s", len, errno, strerror(errno));
+        goto err;
+    }
+
+    while (n < len) {
+        ret = thandle->transport->read(thandle, buffer + n, len - n);
+        if (ret <= 0) {
+            D(WARN, "transport read failed, ret=%d %s", ret, strerror(-ret));
+            break;
+        }
+        n += ret;
+    }
+
+    munmap(buffer, len);
+
+    if (n != len)
+        goto err;
+
+    return fd;
+
+err:
+    close(fd);
+    transport_handle_close(thandle);
+    return -1;
+}
+
+static void *transport_data_thread(void *arg)
+{
+    struct transport_handle *thandle = arg;
+    struct protocol_handle *phandle = create_protocol_handle(thandle);
+
+    while (!thandle->stopped) {
+        int ret;
+        char buffer[COMMAND_BUF_SIZE + 1];
+        D(VERBOSE, "transport_data_thread\n");
+
+        ret = thandle->transport->read(thandle, buffer, COMMAND_BUF_SIZE);
+        if (ret <= 0) {
+            D(DEBUG, "ret = %d\n", ret);
+            break;
+        }
+        if (ret > 0) {
+            buffer[ret] = 0;
+            protocol_handle_command(phandle, buffer);
+        }
+    }
+
+    transport_handle_close(thandle);
+    free(thandle);
+
+    return NULL;
+}
+
+static void *transport_connect_thread(void *arg)
+{
+    struct transport *transport = arg;
+    while (!transport->stopped) {
+        struct transport_handle *thandle;
+        pthread_t thread;
+        pthread_attr_t attr;
+
+        D(VERBOSE, "transport_connect_thread\n");
+        thandle = transport->connect(transport);
+        if (thandle == NULL) {
+            D(ERR, "transport connect failed\n");
+            sleep(1);
+            continue;
+        }
+        thandle->transport = transport;
+
+        pthread_attr_init(&attr);
+        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+        pthread_create(&thread, &attr, transport_data_thread, thandle);
+
+        sleep(1);
+    }
+
+    return NULL;
+}
+
+void transport_register(struct transport *transport)
+{
+    pthread_t thread;
+    pthread_attr_t attr;
+
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+    pthread_create(&thread, &attr, transport_connect_thread, transport);
+}