gtp: let userspace handle packets for invalid tunnels

enable userspace to send error replies for invalid tunnels
Acked-by: NHarald Welte <laforge@netfilter.org>
Signed-off-by: NAndreas Schultz <aschultz@tpip.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/gtp.c

@@ -198,12 +198,12 @@ static int gtp0_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb,
 	pctx = gtp0_pdp_find(gtp, be64_to_cpu(gtp0->tid));
 	if (!pctx) {
 		netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb);
-		return -1;
+		return 1;
 	}
 
 	if (!gtp_check_src_ms(skb, pctx, hdrlen)) {
 		netdev_dbg(gtp->dev, "No PDP ctx for this MS\n");
-		return -1;
+		return 1;
 	}
 
 	/* Get rid of the GTP + UDP headers. */
@@ -247,12 +247,12 @@ static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb,
 	pctx = gtp1_pdp_find(gtp, ntohl(gtp1->tid));
 	if (!pctx) {
 		netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb);
-		return -1;
+		return 1;
 	}
 
 	if (!gtp_check_src_ms(skb, pctx, hdrlen)) {
 		netdev_dbg(gtp->dev, "No PDP ctx for this MS\n");
-		return -1;
+		return 1;
 	}
 
 	/* Get rid of the GTP + UDP headers. */