From mboxrd@z Thu Jan 1 00:00:00 1970 From: nick black Subject: is PACKET_TX_RING expected to work on loopback? Date: Thu, 6 Oct 2011 14:37:32 -0400 Message-ID: <20111006183732.GA24014@qemfd.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-net@vger.kernel.org To: Vitali Lovitch , Johann Baudy , David Miller Return-path: Received: from mail-gy0-f174.google.com ([209.85.160.174]:57305 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755185Ab1JFTEg convert rfc822-to-8bit (ORCPT ); Thu, 6 Oct 2011 15:04:36 -0400 Received: by gyg10 with SMTP id 10so2904424gyg.19 for ; Thu, 06 Oct 2011 12:04:35 -0700 (PDT) Received: from recombinator.qemfd.net (localhost.localdomain [127.0.0.1]) by vps.qemfd.net (Postfix) with ESMTP id 2CBC62B136 for ; Thu, 6 Oct 2011 15:04:33 -0400 (EDT) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Hey there. I'm developing an application which makes use of PACKET_TX_R= ING (http://dank.qemfd.net/dankwiki/index.php/Omphalos), one mmap'd RX and = TX socket per interface. When I transmit on wireless/ethernet devices, the packets flow out fine, and I get responses. When I transmit on loopback, I can see the packets using tcpdump -i lo,= =20 send() returns 0, and the frame is set back to TP_STATUS_AVAILABLE. Checksums are properly set and the packets appear well-formed in Wiresh= ark. I can't seem to read the packets, however; neither the intended DNS ser= ver (verified via dnsmasq -d and strace) nor my own socat udp-listen proces= s seem to get the packets. Is PACKET_TX_RING expected to work on loopback? Thanks! --=20 nick black "A main cause of the Roman Empire's fall was that=E2=80=93lacking zero=E2= =80=93they had no way to indicate successful termination of their C programs."