Index: vl.c
===================================================================
RCS file: /sources/qemu/qemu/vl.c,v
retrieving revision 1.317
diff -u -r1.317 vl.c
--- vl.c	29 Jun 2007 23:26:08 -0000	1.317
+++ vl.c	1 Jul 2007 11:42:53 -0000
@@ -3020,21 +3020,66 @@
     }
 }
 
+static inline int is_hex_char(char c)
+{
+	return (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F') || (c >= '0' && c <= '9');
+}
+
 static int parse_macaddr(uint8_t *macaddr, const char *p)
 {
-    int i;
-    for(i = 0; i < 6; i++) {
-        macaddr[i] = strtol(p, (char **)&p, 16);
-        if (i == 5) {
-            if (*p != '\0') 
-                return -1;
-        } else {
-            if (*p != ':') 
-                return -1;
-            p++;
-        }
-    }
-    return 0;
+	if (NULL == p)
+		return -1;
+	
+	if ('-' == *p || '+' == *p)
+	{
+		/* an offset relative to the default address */
+		char *endptr;
+		int offset = strtol(p, (char**)&endptr, 0);
+		if ('\0' != *endptr)
+			return -1;
+		/* convert the macaddr to 64 bit num, add the offset and convert it back */
+		uint64_t macaddr_l = ((uint64_t)macaddr[0] << 40UL) + ((uint64_t)macaddr[1] << 32UL) + 
+			((uint64_t)macaddr[2] << 24UL) + ((uint64_t)macaddr[3] << 16UL) + ((uint64_t)macaddr[4] << 8UL) +
+			((uint64_t)macaddr[5]);
+		macaddr_l += offset;
+		macaddr[0] = (uint8_t)((macaddr_l >> 40UL) & 0xFF);
+		macaddr[1] = (uint8_t)((macaddr_l >> 32UL) & 0xFF);
+		macaddr[2] = (uint8_t)((macaddr_l >> 24UL) & 0xFF);
+		macaddr[3] = (uint8_t)((macaddr_l >> 16UL) & 0xFF);
+		macaddr[4] = (uint8_t)((macaddr_l >>  8UL) & 0xFF);
+		macaddr[5] = (uint8_t)((macaddr_l >>  0UL) & 0xFF);
+	}
+	else if (is_hex_char(*p))
+	{
+		/* a full mac address - hopefully :) */
+		int mac_i = 0;
+		while ('\0' != *p)
+		{
+			/* skip separator chars */
+			while ( ('\0' != *p) && (':' == *p || '-' == *p) ) p++;
+			char hex_chars[3]; hex_chars[2] = '\0';
+			/* get two hexdec chars and parse it */
+			if ( is_hex_char(*p) && is_hex_char(*(p+1)) )
+			{
+				hex_chars[0] = *p; hex_chars[1] = *(p+1);
+				macaddr[mac_i] = strtol(hex_chars, NULL, 16);
+				p += 2; mac_i++;
+				/* the string should contain only 6 pairs */
+				if (mac_i >= 6 && *p != '\0') 
+					return -1;
+			}
+			else
+			{
+				return -1;
+			}
+		}
+	}
+	else
+	{
+		/* error, unexpected character */
+		return -1;
+	}
+	return 0;
 }
 
 static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)