vrouter: initialize sandesh; implement random() functions

Changes required to support Contrail on Windows:
- windows/vr_win_transport.c - functions used to initialize sandesh and
  vr_message layer on Windows
- windows/windows_random.c - implement get_random_bytes() and
  get_random_ulong() for Windows

Initial work:
  https://github.com/codilime/contrail-vrouter/commits/windows

Change-Id: I6e0d7b24c6d43f5657bd751f53c721a5397289a5
Partial-Bug: #1734699

windows/vr_win_transport.c

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2017 Juniper Networks, Inc. All rights reserved.
+ */
+#include <precomp.h>
+
+#include "vr_message.h"
+#include "vr_sandesh.h"
+
+static ULONG WIN_TRANSPORT_TAG = 'ARTV';
+
+static char *
+win_trans_alloc(unsigned int size)
+{
+    char *buffer;
+    size_t allocation_size;
+
+    allocation_size = NLMSG_ALIGN(size) + NETLINK_HEADER_LEN;
+    buffer = ExAllocatePoolWithTag(NonPagedPoolNx, allocation_size, WIN_TRANSPORT_TAG);
+    if (buffer == NULL)
+        return NULL;
+
+    return buffer + NETLINK_HEADER_LEN;
+}
+
+static void
+win_trans_free(char *buf)
+{
+    ASSERT(buf != NULL);
+    ExFreePool(buf - NETLINK_HEADER_LEN);
+}
+
+static struct vr_mtransport win_transport = {
+    .mtrans_alloc   =   win_trans_alloc,
+    .mtrans_free    =   win_trans_free,
+};
+
+void
+vr_transport_exit(void)
+{
+    vr_message_transport_unregister(&win_transport);
+}
+
+int
+vr_transport_init(void)
+{
+    int ret;
+
+    ret = vr_message_transport_register(&win_transport);
+    if (ret) {
+        DbgPrint("%s: error on transport register = %d\n", __func__, ret);
+        return ret;
+    }
+
+    return 0;
+}
+
+NTSTATUS
+vr_message_init(void)
+{
+    int ret = vr_sandesh_init();
+    if (ret) {
+        DbgPrint("%s: vr_sandesh_init() failed with return %d\n", __func__, ret);
+        return NDIS_STATUS_FAILURE;
+    }
+
+    ret = vr_transport_init();
+    if (ret) {
+        DbgPrint("%s: vr_transport_init() failed with return %d", __func__, ret);
+        vr_sandesh_exit();
+        return NDIS_STATUS_FAILURE;
+    }
+
+    return NDIS_STATUS_SUCCESS;
+}
+
+void
+vr_message_exit(void)
+{
+    vr_transport_exit();
+    vr_sandesh_exit();
+}

windows/windows_random.c

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2017 Juniper Networks, Inc. All rights reserved.
+ */
+#include "precomp.h"
+#include "vr_os.h"
+
+ULONG seed;
+bool isSeedInitialized;
+
+static void prepareSeed() {
+    if (!isSeedInitialized) {
+        seed = KeQueryPerformanceCounter(NULL).LowPart;
+        isSeedInitialized = TRUE;
+    }
+}
+
+// make sure prepareSeed has been run before using this function
+static ULONG get_random_ulong() {
+    const ULONG a = 1103515245UL, c = 12345UL;
+    seed = a * seed + c;
+    return seed;
+}
+
+void get_random_bytes(void *buf, int nbytes) {
+    ULONG t;
+    prepareSeed();
+    while (nbytes > sizeof(ULONG)) {
+        t = get_random_ulong();
+        memcpy(buf, &t, sizeof(ULONG));
+        nbytes -= sizeof(ULONG);
+        buf = (PINT8)buf + sizeof(ULONG);
+    }
+    t = get_random_ulong();
+    memcpy(buf, &t, nbytes);
+}