[PATCH v2] buffer: Add buf_read_u64() and buf_write_u64()

From: Lev Stipakov <[email protected]>

Add 64-bit big-endian buffer accessors alongside the existing 8/16/32-bit
helpers. There is no portable 64-bit byte-order primitive, so the value is
handled as two big-endian 32-bit halves (most significant first).

buf_read_u64() reports success via a bool out-parameter, mirroring
buf_read_u32(): every 64-bit value is a legal result, leaving no room for
an in-band sentinel.

Change-Id: Ic677f43fc3eb0052f8e80d9a7f098d34ad03dfe1
Signed-off-by: Lev Stipakov <[email protected]>
Acked-by: Frank Lichtenheld <[email protected]>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1740
---

This change was reviewed on Gerrit and approved by at least one
developer. I request to merge it to master.

Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1740
This mail reflects revision 2 of this Change.

Acked-by according to Gerrit (reflected above):
Frank Lichtenheld <[email protected]>

        
diff --git a/src/openvpn/buffer.h b/src/openvpn/buffer.h
index fcc923b..1db9367 100644
--- a/src/openvpn/buffer.h
+++ b/src/openvpn/buffer.h
@@ -25,6 +25,7 @@
 
 #include "basic.h"
 #include "error.h"
+#include "integer.h"
 
 #define BUF_SIZE_MAX 1000000
 
@@ -702,6 +703,13 @@
 }
 
 static inline bool
+buf_write_u64(struct buffer *dest, uint64_t data)
+{
+    uint64_t u64 = htonll(data);
+    return buf_write(dest, &u64, sizeof(uint64_t));
+}
+
+static inline bool
 buf_copy(struct buffer *dest, const struct buffer *src)
 {
     return buf_write(dest, BPTR(src), BLENZ(src));
@@ -827,6 +835,30 @@
     }
 }
 
+/* Read a 64-bit big-endian value (see buf_write_u64()). Sets *good to indicate
+ * success, like buf_read_u32(). */
+static inline uint64_t
+buf_read_u64(struct buffer *buf, bool *good)
+{
+    uint64_t ret;
+    if (!buf_read(buf, &ret, sizeof(uint64_t)))
+    {
+        if (good)
+        {
+            *good = false;
+        }
+        return 0;
+    }
+    else
+    {
+        if (good)
+        {
+            *good = true;
+        }
+        return ntohll(ret);
+    }
+}
+
 /** Return true if buffer contents are equal */
 static inline bool
 buf_equal(const struct buffer *a, const struct buffer *b)