datapath: Consider tunnels to have no MTU, fixing jumbo frame support.

[openvswitch] / lib / util.h

diff --git a/lib/util.h b/lib/util.h
index 703b93cf4c6e528ec0d5c48ae5034b03f0cd710f..f3bf80c6eaeddc760344b743bb30785d2258b985 100644 (file)
--- a/lib/util.h
+++ b/lib/util.h
@@ -77,20 +77,37 @@ extern const char *program_name;
 
 #define NOT_REACHED() abort()
 
+/* Given a pointer-typed lvalue OBJECT, expands to a pointer type that may be
+ * assigned to OBJECT. */
+#ifdef __GNUC__
+#define OVS_TYPEOF(OBJECT) typeof(OBJECT)
+#else
+#define OVS_TYPEOF(OBJECT) void *
+#endif
+
 /* Given POINTER, the address of the given MEMBER in a STRUCT object, returns
    the STRUCT object. */
 #define CONTAINER_OF(POINTER, STRUCT, MEMBER)                           \
         ((STRUCT *) (void *) ((char *) (POINTER) - offsetof (STRUCT, MEMBER)))
 
 /* Given POINTER, the address of the given MEMBER within an object of the type
- * that that OBJECT points to, returns OBJECT as a "void *" pointer.  OBJECT
- * must be an lvalue.
+ * that that OBJECT points to, returns OBJECT as an assignment-compatible
+ * pointer type (either the correct pointer type or "void *").  OBJECT must be
+ * an lvalue.
  *
  * This is the same as CONTAINER_OF except that it infers the structure type
  * from the type of '*OBJECT'. */
 #define OBJECT_CONTAINING(POINTER, OBJECT, MEMBER)                      \
-        ((void *) ((char *) (POINTER)                                   \
-                   - ((char *) &(OBJECT)->MEMBER - (char *) (OBJECT))))
+    ((OVS_TYPEOF(OBJECT)) (void *)                                      \
+     ((char *) (POINTER) - ((char *) &(OBJECT)->MEMBER - (char *) (OBJECT))))
+
+/* Given POINTER, the address of the given MEMBER within an object of the type
+ * that that OBJECT points to, assigns the address of the outer object to
+ * OBJECT, which must be an lvalue.
+ *
+ * Evaluates to 1. */
+#define ASSIGN_CONTAINER(OBJECT, POINTER, MEMBER) \
+    ((OBJECT) = OBJECT_CONTAINING(POINTER, OBJECT, MEMBER), 1)
 
 #ifdef  __cplusplus
 extern "C" {
@@ -120,6 +137,7 @@ void ovs_strlcpy(char *dst, const char *src, size_t size);
 void ovs_fatal(int err_no, const char *format, ...)
     PRINTF_FORMAT(2, 3) NO_RETURN;
 void ovs_error(int err_no, const char *format, ...) PRINTF_FORMAT(2, 3);
+const char *ovs_retval_to_string(int);
 void ovs_hex_dump(FILE *, const void *, size_t, uintptr_t offset, bool ascii);
 
 bool str_to_int(const char *, int base, int *);