hostapd: Make it possible to remove addresses from maclists

It is already possible to add MAC addresses at runtime. This patch
allows also to remove some of them by using the prefix "-" in the
address file.

Signed-off-by: Emanuel Taube <emanuel.taube@gmail.com>

hostapd/config_file.c

@@ -129,6 +129,8 @@ static int hostapd_config_read_maclist(const char *fname,
 	}
 
 	while (fgets(buf, sizeof(buf), f)) {
+		int i, rem = 0;
+
 		line++;
 
 		if (buf[0] == '#')
@@ -143,14 +145,32 @@ static int hostapd_config_read_maclist(const char *fname,
 		}
 		if (buf[0] == '\0')
 			continue;
+		pos = buf;
+		if (buf[0] == '-') {
+			rem = 1;
+			pos++;
+		}
 
-		if (hwaddr_aton(buf, addr)) {
+		if (hwaddr_aton(pos, addr)) {
 			wpa_printf(MSG_ERROR, "Invalid MAC address '%s' at "
-				   "line %d in '%s'", buf, line, fname);
+				   "line %d in '%s'", pos, line, fname);
 			fclose(f);
 			return -1;
 		}
 
+		if (rem) {
+			i = 0;
+			while (i < *num) {
+				if (os_memcmp((*acl)[i].addr, addr, ETH_ALEN) ==
+				    0) {
+					os_remove_in_array(*acl, *num,
+							   sizeof(**acl), i);
+					(*num)--;
+				} else
+					i++;
+			}
+			continue;
+		}
 		vlan_id = 0;
 		pos = buf;
 		while (*pos != '\0' && *pos != ' ' && *pos != '\t')