From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: 2.6.18-rc6 memory mapped pcap truncates outgoing TCP packets, but not icmp Date: Thu, 14 Sep 2006 12:02:26 +0200 Message-ID: <450928B2.4090003@trash.net> References: <20060913112307.GA1374@outpost.ds9a.nl> <45085185.2060904@trash.net> <20060914085618.GA4623@outpost.ds9a.nl> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------030808020009080306090908" Cc: cpw@lanl.gov, netdev@vger.kernel.org Return-path: Received: from stinky.trash.net ([213.144.137.162]:16811 "EHLO stinky.trash.net") by vger.kernel.org with ESMTP id S1750715AbWINKC2 (ORCPT ); Thu, 14 Sep 2006 06:02:28 -0400 To: bert hubert In-Reply-To: <20060914085618.GA4623@outpost.ds9a.nl> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org This is a multi-part message in MIME format. --------------030808020009080306090908 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit bert hubert wrote: > On Wed, Sep 13, 2006 at 08:44:21PM +0200, Patrick McHardy wrote: > > >>Are you using TSO on the outgoing device? If so please try to log the >>packet using iptables to see if it really is a TSO packet. > > > Good catch! I turned off TSO and things are working fine again. > > Is this a known problem, should it be documented or fixed? I'm more than > willing to write up some warnings should this be a good idea. It appears to be intentionally, but I don't see a reason for it. Can you try if this patch makes it work as expected? --------------030808020009080306090908 Content-Type: text/plain; name="x" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="x" [PACKET]: Don't truncate non-linear skbs with mmaped IO Non-linear skbs are truncated to their linear part with mmaped IO. Fix by using skb_copy_bits instead of memcpy. Signed-off-by: Patrick McHardy --- commit 6e184976552a407c331f9b4e52b2c26fcae46ee7 tree 1bb4fc2b65179a51e795dc07908277b83cc0921a parent 9f737633e6ee54fc174282d49b2559bd2208391d author Patrick McHardy Thu, 14 Sep 2006 11:59:09 +0200 committer Patrick McHardy Thu, 14 Sep 2006 11:59:09 +0200 net/packet/af_packet.c | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index f9cef36..4172a52 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -626,8 +626,6 @@ static int tpacket_rcv(struct sk_buff *s if ((int)snaplen < 0) snaplen = 0; } - if (snaplen > skb->len-skb->data_len) - snaplen = skb->len-skb->data_len; spin_lock(&sk->sk_receive_queue.lock); h = (struct tpacket_hdr *)packet_lookup_frame(po, po->head); @@ -644,7 +642,7 @@ static int tpacket_rcv(struct sk_buff *s status &= ~TP_STATUS_LOSING; spin_unlock(&sk->sk_receive_queue.lock); - memcpy((u8*)h + macoff, skb->data, snaplen); + skb_copy_bits(skb, 0, (u8*)h + macoff, snaplen); h->tp_len = skb->len; h->tp_snaplen = snaplen; --------------030808020009080306090908--