From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <andrw.wng@gmail.com>
Received: from mail-oi0-f49.google.com (mail-oi0-f49.google.com
 [209.85.218.49]) by dpdk.org (Postfix) with ESMTP id E29A02661
 for <users@dpdk.org>; Wed,  8 Aug 2018 18:57:36 +0200 (CEST)
Received: by mail-oi0-f49.google.com with SMTP id s198-v6so4888467oih.11
 for <users@dpdk.org>; Wed, 08 Aug 2018 09:57:36 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
 h=mime-version:from:date:message-id:subject:to;
 bh=xJRhtGHeDKHm7hBvhFRY+/Ym66iJ3nWA5CWLAQGtULg=;
 b=l6+yitbuY6Sbbq/+DK66kEsqlJ5MmmRykYX/TVBDUKMx0qnMeQBZMbv1QhAnzNL1tJ
 oBxMzl+Wd5FiRz5zpIyDkialrU5FrPRMiKE+NOzjnBEVM8zIPCGme6DM0dTZm3eDp2Cd
 oMPcrJoHKMniPS3E56GnG5yignBu7hgpCRIupy/9ie4xYHy8FQJM+UamprKc0ZACCT5Q
 Ge7wA5Yn0gUskvivsxafXsAD0xCe/G3FLqqRqyqHsFvPLDFEqqK10bkiDgif22bp1wsM
 KUwMrAHAB1r4961X83SPY65EynPpQu1oo+pCo4JKzFlbpbHeZn/U/o0jsSCIqZo4ShP8
 m9Iw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:mime-version:from:date:message-id:subject:to;
 bh=xJRhtGHeDKHm7hBvhFRY+/Ym66iJ3nWA5CWLAQGtULg=;
 b=C9/1ttWihIM0Uiytqv7iXdjZ5POew7x2kyT4KdFTsXckuFr/X6N9X4JPG5p/du1q1F
 5EvS2Sn/pLYvdZ0G9OO1QLLtWetBpeWm3iOjCxi8Xnu0yDvhrfjN2zwgy9ttZtnCupcm
 67tPg/DUf/uy7f12ZRTVMbqXhxBAEQ+MOsf6ZLi1sjvR+WYfHoCSBCmMoZWrS+IoLUyn
 uLD05tn27SRHBBGw10zrX5yR742jFofcU1tSiFGfaq3VTrEkef7iJ536nCRRcC71JwwD
 FcqdLTE82+9yvdBADRtk6Xo1PpoH3PJZ7zSIGmCfZc4oTlLljbNgzuREnNXsNh/kZvjP
 wxJQ==
X-Gm-Message-State: AOUpUlH+2DiBC4GzjYpuUQXNVfFVCgafiBRNIe4LnSeupVpGT43NMQDx
 Zb9BuI80ItVF9aCZglZ1I83oF3jtqWRWZZSf+zT8Ag==
X-Google-Smtp-Source: AA+uWPw9K6hSpgegxX0EZiVocUbWVSnCVdBXBEfLhXwvxIa+79MFMT8FQQrZc7ehHReLxNLbdVgg3fCQ1BjkxrnYK90=
X-Received: by 2002:aca:d682:: with SMTP id
 n124-v6mr3919525oig.32.1533747455966; 
 Wed, 08 Aug 2018 09:57:35 -0700 (PDT)
MIME-Version: 1.0
Received: by 2002:aca:eb52:0:0:0:0:0 with HTTP;
 Wed, 8 Aug 2018 09:57:35 -0700 (PDT)
From: Andrew Wang <andrw.wng@gmail.com>
Date: Wed, 8 Aug 2018 12:57:35 -0400
Message-ID: <CANEosPAzArSSEzpDqUfg4nSDLz=2882hPSqNJ5bNxZae=T_Esw@mail.gmail.com>
To: users@dpdk.org
Content-Type: text/plain; charset="UTF-8"
X-Content-Filtered-By: Mailman/MimeDel 2.1.15
Subject: [dpdk-users] AF_PACKET pmd and linux networking stack
X-BeenThere: users@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK usage discussions <users.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/users>,
 <mailto:users-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/users/>
List-Post: <mailto:users@dpdk.org>
List-Help: <mailto:users-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/users>,
 <mailto:users-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Wed, 08 Aug 2018 16:57:37 -0000

Hi

Is there a way of preventing the linux kernel networking stack from
handling packets when using the AF_PACKET pmd?

Our DPDK app is running on a node that is attracting traffic for a VIP and
for which it has a blackhole routing rule (to drop all the incoming packets
for that VIP).

The intention was to have our DPDK app (running on AF_PACKET pmd for now -
we're still developing the app) grab those packets, process and send them
out (with a different address).

Right now we can actually see those packets in our dpdk app, we process
them, give them a different address, but it seems that the linux kernel
networking stack is still dropping them.

When the blackhole rule is removed we see the outgoing packet with correct
header, but also a destination unreachable message is sent out, suggesting
the kernel is also handling the packet. We see the same behavior when using
iptables to drop packets (instead of blackhole route).

Any suggestions appreciated.

Thanks
Andrew