datapath-protocol: Use Linux kernel types directly.

We want datapath-protocol.h to be acceptable as a Linux kernel header, so
it must use Linux kernel types and must not have references to Open vSwitch
symbols or header files.  This commit primarily makes that change to
datapath-protocol.h.

At the same time, at least for now we also want datapath-protocol.h to be
usable on non-Linux platforms, so we need some kind of compatiblity.  Thus,
this commit also introduces a <linux/types.h> header file that defines the
necessary Linux kernel types on non-Linux platforms.

In turn, this requires openvswitch/types.h to use the Linux types directly
for ovs_be<N>; otherwise, sparse complains because now __be<N> and
ovs_be<N> are incompatible from its perspective, so this commit makes that
change too.

I don't have a non-Linux kernel platform readily available, so I only
tested the non-Linux part of the linux/types.h substitute by forcing that
case to be triggered with #if 0.  It worked, except for errors in actual
Linux kernel headers included explicitly from OVS source files, so I think
it's likely to work in practice.

Bug #7559.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>

include/linux/types.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2011 Nicira Networks.
+ *
+ * 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.
+ */
+
+#ifndef LINUX_TYPES_H
+#define LINUX_TYPES_H 1
+
+/* On Linux, this header file just includes <linux/types.h>.
+ *
+ * On other platforms, this header file implements just enough of
+ * <linux/types.h> to allow datapath-protocol.h to work, that is, it defines
+ * the __u<N> and __be<N> types. */
+
+#if __KERNEL__ || HAVE_LINUX_TYPES_H
+#include_next <linux/types.h>
+#else  /* no <linux/types.h> */
+#include <stdint.h>
+
+#ifdef __CHECKER__
+#define __bitwise__ __attribute__((bitwise))
+#else
+#define __bitwise__
+#endif
+
+typedef uint8_t  __u8;
+typedef uint16_t __u16;
+typedef uint32_t __u32;
+typedef uint64_t __u64;
+
+typedef uint16_t __bitwise__ __be16;
+typedef uint32_t __bitwise__ __be32;
+typedef uint64_t __bitwise__ __be64;
+#endif	/* no <linux/types.h> */
+
+#endif /* <linux/types.h> */