gtp: clear DF bit on GTP packet tx

Andreas Schultz · davem330 · commit c6ce1d08eede · 2017-01-27T10:39:09.000-05:00
3GPP TS 29.281 and 3GPP TS 29.060 imply that GTP-U packets should be
sent with the DF bit cleared. For example 3GPP TS 29.060, Release 8,
Section 13.2.2:

&gt; Backbone router: Any router in the backbone may fragment the GTP
&gt; packet if needed, according to IPv4.

Signed-off-by: Andreas Schultz &lt;aschultz@tpip.net&gt;
Acked-by: Harald Welte &lt;laforge@netfilter.org&gt;
Acked-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
@@ -612,7 +612,7 @@ static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 				    pktinfo.fl4.saddr, pktinfo.fl4.daddr,
 				    pktinfo.iph->tos,
 				    ip4_dst_hoplimit(&pktinfo.rt->dst),
-				    htons(IP_DF),
+				    0,
 				    pktinfo.gtph_port, pktinfo.gtph_port,
 				    true, false);
 		break;
