From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net v2 2/3] packet: always probe for transport header Date: Wed, 11 Nov 2015 13:08:23 +0800 Message-ID: <5642CD47.4020101@redhat.com> References: <4adce55fc6c4aa8f05306af650659a1326537a1a.1447191361.git.daniel@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: edumazet@google.com, willemb@google.com, tklauser@distanz.ch, netdev@vger.kernel.org To: Daniel Borkmann , davem@davemloft.net Return-path: Received: from mx1.redhat.com ([209.132.183.28]:47983 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750778AbbKKFIb (ORCPT ); Wed, 11 Nov 2015 00:08:31 -0500 In-Reply-To: <4adce55fc6c4aa8f05306af650659a1326537a1a.1447191361.git.daniel@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: On 11/11/2015 06:03 AM, Daniel Borkmann wrote: > 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 > Cc: Jason Wang > --- > 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 80c36c0..bdecf17 100644 > --- a/net/packet/af_packet.c > +++ b/net/packet/af_packet.c > @@ -2447,8 +2447,7 @@ 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; > } > @@ -2808,8 +2807,8 @@ 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; > Acked-by: Jason Wang