typedef __be16 ovs_be16;
typedef __be32 ovs_be32;
typedef __be64 ovs_be64;
+
+#define OVS_BE16_MAX ((OVS_FORCE ovs_be16) 0xffff)
+#define OVS_BE32_MAX ((OVS_FORCE ovs_be32) 0xffffffff)
+#define OVS_BE64_MAX ((OVS_FORCE ovs_be64) 0xffffffffffffffffULL)
\f
-/* Netlink and OpenFlow both contain 64-bit values that are only guaranteed to
- * be aligned on 32-bit boundaries. These types help.
+/* These types help with a few funny situations:
+ *
+ * - The Ethernet header is 14 bytes long, which misaligns everything after
+ * that. One can put 2 "shim" bytes before the Ethernet header, but this
+ * helps only if there is exactly one Ethernet header. If there are two,
+ * as with GRE and VXLAN (and if the inner header doesn't use this
+ * trick--GRE and VXLAN don't) then you have the choice of aligning the
+ * inner data or the outer data. So it seems better to treat 32-bit fields
+ * in protocol headers as aligned only on 16-bit boundaries.
+ *
+ * - ARP headers contain misaligned 32-bit fields.
+ *
+ * - Netlink and OpenFlow contain 64-bit values that are only guaranteed to
+ * be aligned on 32-bit boundaries.
*
* lib/unaligned.h has helper functions for accessing these. */
+/* A 32-bit value, in host byte order, that is only aligned on a 16-bit
+ * boundary. */
+typedef struct {
+#ifdef WORDS_BIGENDIAN
+ uint16_t hi, lo;
+#else
+ uint16_t lo, hi;
+#endif
+} ovs_16aligned_u32;
+
+/* A 32-bit value, in network byte order, that is only aligned on a 16-bit
+ * boundary. */
+typedef struct {
+ ovs_be16 hi, lo;
+} ovs_16aligned_be32;
+
/* A 64-bit value, in host byte order, that is only aligned on a 32-bit
* boundary. */
typedef struct {