From fa198865e1af85f2868fceea03e64dc46ada9a1c Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Sun, 13 May 2018 21:18:49 +0200
Subject: [PATCH] add missing #define

---
 src/nat/gnunet-helper-nat-client.c | 11 +++++++++++
 src/nat/gnunet-helper-nat-server.c | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/src/nat/gnunet-helper-nat-client.c b/src/nat/gnunet-helper-nat-client.c
index 9768dd856..359e529b0 100644
--- a/src/nat/gnunet-helper-nat-client.c
+++ b/src/nat/gnunet-helper-nat-client.c
@@ -66,6 +66,17 @@
 #define ICMP_TIME_EXCEEDED 11
 #endif
 
+/**
+ * Call memcpy() but check for @a n being 0 first. In the latter
+ * case, it is now safe to pass NULL for @a src or @a dst.
+ * Unlike traditional memcpy(), returns nothing.
+ *
+ * @param dst destination of the copy, may be NULL if @a n is zero
+ * @param src source of the copy, may be NULL if @a n is zero
+ * @param n number of bytes to copy
+ */
+#define GNUNET_memcpy(dst,src,n) do { if (0 != n) { (void) memcpy (dst,src,n); } } while (0)
+
 /**
  * Must match IP given in the server.
  */
diff --git a/src/nat/gnunet-helper-nat-server.c b/src/nat/gnunet-helper-nat-server.c
index f35649152..b8f499b4d 100644
--- a/src/nat/gnunet-helper-nat-server.c
+++ b/src/nat/gnunet-helper-nat-server.c
@@ -70,6 +70,17 @@
 #define ICMP_TIME_EXCEEDED 11
 #endif
 
+/**
+ * Call memcpy() but check for @a n being 0 first. In the latter
+ * case, it is now safe to pass NULL for @a src or @a dst.
+ * Unlike traditional memcpy(), returns nothing.
+ *
+ * @param dst destination of the copy, may be NULL if @a n is zero
+ * @param src source of the copy, may be NULL if @a n is zero
+ * @param n number of bytes to copy
+ */
+#define GNUNET_memcpy(dst,src,n) do { if (0 != n) { (void) memcpy (dst,src,n); } } while (0)
+
 /**
  * Should we print some debug output?
  */
-- 
2.25.1