util: add qemu_ether_ntoa

This adds a helper to format ethernet MAC address.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>

include/qemu-common.h

@@ -472,4 +472,6 @@ size_t buffer_find_nonzero_offset(const void *buf, size_t len);
  */
 int parse_debug_env(const char *name, int max, int initial);
 
+const char *qemu_ether_ntoa(const MACAddr *mac);
+
 #endif

util/cutils.c

@@ -27,6 +27,7 @@
 
 #include "qemu/sockets.h"
 #include "qemu/iov.h"
+#include "net/net.h"
 
 void strpadcpy(char *buf, int buf_size, const char *str, char pad)
 {
@@ -530,3 +531,16 @@ int parse_debug_env(const char *name, int max, int initial)
     }
     return debug;
 }
+
+/*
+ * Helper to print ethernet mac address
+ */
+const char *qemu_ether_ntoa(const MACAddr *mac)
+{
+    static char ret[18];
+
+    snprintf(ret, sizeof(ret), "%02x:%02x:%02x:%02x:%02x:%02x",
+             mac->a[0], mac->a[1], mac->a[2], mac->a[3], mac->a[4], mac->a[5]);
+
+    return ret;
+}