diff --git a/net/netfilter/xt_DSCP.c b/net/netfilter/xt_DSCP.c
index 0a229191e55b2f8e15e00e459b2ceb20fe226893..ae8271652efa9cf5a6f939fcedc3238ca6c865c7 100644
--- a/net/netfilter/xt_DSCP.c
+++ b/net/netfilter/xt_DSCP.c
@@ -99,7 +99,7 @@ tos_tg6(struct sk_buff *skb, const struct xt_action_param *par)
 	u_int8_t orig, nv;
 
 	orig = ipv6_get_dsfield(iph);
-	nv   = (orig & info->tos_mask) ^ info->tos_value;
+	nv   = (orig & ~info->tos_mask) ^ info->tos_value;
 
 	if (orig != nv) {
 		if (!skb_make_writable(skb, sizeof(struct iphdr)))