Subject: [PATCH 11/37] packet: always probe for transport header

From: Daniel Borkmann <[email-masked]>
Date: Wed, 11 Nov 2015 23:25:41 +0100

[ Upstream commit 8fd6c80d9dd938ca338c70698533a7e304752846 ]

We concluded that the skb_probe_transport_header() should better be
called unconditionally. Avoiding the call into the flow dissector has
also not really much to do with the direct xmit mode.

While it seems that only virtio_net code makes use of GSO from non
RX/TX ring packet socket paths, we should probe for a transport header
nevertheless before they hit devices.

Reference: http://thread.gmane.org/gmane.linux.network/386173/
Signed-off-by: Daniel Borkmann <[email-masked]>
Acked-by: Jason Wang <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/packet/af_packet.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index ff4586f..5b1eadb 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2328,8 +2328,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
 		len = ((to_write > len_max) ? len_max : to_write);
 	}
 
-	if (!packet_use_direct_xmit(po))
-		skb_probe_transport_header(skb, 0);
+	skb_probe_transport_header(skb, 0);
 
 	return tp_len;
 }
@@ -2681,8 +2680,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
 		len += vnet_hdr_len;
 	}
 
-	if (!packet_use_direct_xmit(po))
-		skb_probe_transport_header(skb, reserve);
+	skb_probe_transport_header(skb, reserve);
+
 	if (unlikely(extra_len == 4))
 		skb->no_fcs = 1;
 
-- 
2.1.0