From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Turull Subject: [PATCH] pktgen: fix transmission headers with frags=0 Date: Mon, 14 Mar 2011 14:22:06 +0100 Message-ID: <4D7E167E.2090807@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Robert Olsson , Jens Laas , Voravit Tanyingyong , Daniel Turull To: netdev@vger.kernel.org Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:54556 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755026Ab1CNNWM (ORCPT ); Mon, 14 Mar 2011 09:22:12 -0400 Received: by fxm17 with SMTP id 17so2875153fxm.19 for ; Mon, 14 Mar 2011 06:22:11 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: The headers of pktgen were incorrectly added in a pktgen packet without frags (frags=0). There was an offset in the pktgen headers. The cause was in reusing the pgh variable as a return variable in skb_put when adding the payload to the skb. A rename of the variable is done. Signed-off-by: Daniel Turull --- The PKTGEN magic (be9b e955) now starts in the correct offset. Before the patch, it was starting at the end of the packet (be9b) Capture from tcpdump: before patch: 14:57:37.854812 IP 10.0.0.2.discard > 10.254.254.84.discard: UDP, length 18 0x0000: 001b 2157 ed84 001b 215d 01d0 0800 4500 0x0010: 002e 0004 0000 2011 8767 0a00 0002 0afe 0x0020: fe54 0009 0009 001a 0000 0000 0000 b072 0x0030: 9102 00ea ffff 0010 0000 be9b after patch: 14:44:32.896048 IP 10.0.0.2.discard > 10.217.234.56.discard: UDP, length 18 0x0000: 001b 2157 ed84 001b 215d 01d0 0800 4500 0x0010: 002e 0000 0000 2011 9bac 0a00 0002 0ad9 0x0020: ea38 0009 0009 001a 0000 be9b e955 0000 0x0030: 0001 4d7e 1b09 0005 5f23 af00 --- diff --git a/net/core/pktgen.c b/net/core/pktgen.c index f0aec6c..5baa9d9 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -2615,13 +2615,14 @@ static void pktgen_finalize_skb(struct pktgen_dev *pkt_dev, struct sk_buff *skb, { struct timeval timestamp; struct pktgen_hdr *pgh; + void *data; pgh = (struct pktgen_hdr *)skb_put(skb, sizeof(*pgh)); datalen -= sizeof(*pgh); if (pkt_dev->nfrags <= 0) { - pgh = (struct pktgen_hdr *)skb_put(skb, datalen); - memset(pgh + 1, 0, datalen); + data = skb_put(skb, datalen); + memset(data + 1, 0, datalen); } else { int frags = pkt_dev->nfrags; int i, len;