From 5df6cd2115098c2268aeb0701070a51434cdc85c Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@gnumonks.org>
Date: Wed, 19 Feb 2014 23:16:04 +0100
Subject: [PATCH] gtp: fix flags field for GTPv1

Now wireshark shows a well-formed GTPv1 message.
---
 gtp.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/gtp.c b/gtp.c
index 8f0fa36..40ea3b5 100644
--- a/gtp.c
+++ b/gtp.c
@@ -462,7 +462,13 @@ gtp1_push_header(struct sk_buff *skb, struct pdp_ctx *pctx, int payload_len)
 	skb_cow(skb, sizeof(*gtp1) + IP_UDP_LEN);
 	gtp1 = (struct gtp1_header *) skb_push(skb, sizeof(*gtp1));
 
-	gtp1->flags = 0x20; /* V1, GTP-non-prime */
+	/* Bits    8  7  6  5  4  3  2  1
+	 *        +--+--+--+--+--+--+--+--+
+	 *        |version |PT| 1| E| S|PN|
+	 *	  +--+--+--+--+--+--+--+--+
+	 * 	    0  0  1  1  1  0  0  0
+	 */
+	gtp1->flags = 0x38; /* V1, GTP-non-prime */
 	gtp1->type = GTP_TPDU;
 	gtp1->length = htons(payload_len);
 	gtp1->tid = htonl((u32)pctx->tid);