diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 82d9685..ca198c1 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2384,7 +2384,7 @@
 	struct nlattr *extfilt;
 	u32 filter_mask = 0;
 
-	extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct rtgenmsg),
+	extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct ifinfomsg),
 				  IFLA_EXT_MASK);
 	if (extfilt)
 		filter_mask = nla_get_u32(extfilt);