From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id C8BF0A0350 for ; Wed, 1 Jul 2020 16:59:12 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 741A91D41F; Wed, 1 Jul 2020 16:59:12 +0200 (CEST) Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) by dpdk.org (Postfix) with ESMTP id 7FCA61D182 for ; Wed, 1 Jul 2020 16:59:11 +0200 (CEST) Received: by mail-wm1-f50.google.com with SMTP id q15so22763684wmj.2 for ; Wed, 01 Jul 2020 07:59:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JSSGja7G1KzWbz6IOdELRt9mP2Pit6/pdrGbZLT9pEM=; b=D+V+WvW+EJ2e5YwTTjWXpLmOPNxX5Vpxf0lMkOkx/J+n78+6yUZ2tYqafXJolYhu50 C/Zl3VNgpCkLcf5WOnTsRoOv89iWuDQ9WrP85JKYgMnuHxMlnw9jum6PXcA0mUawwKSM 3UG4uRaL4Bwj6Y/YQguZXodifvbSIqIKmGojlFAIWfvF+x2bCfB3mL3Xm/1wK1wxXAbG DMNiy3U/qn4bcv5XQZt3nG3rNedke3yExhkMhF4QxrgUJlwS6hEdUm+HI+wD/5RwY2tf XIjbR1PKPmP8RruWrXHq/VSOmHGDBeavyJX8ckG3V0RLn7TPEyalIu8zJxkRwG2IqefR DNRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JSSGja7G1KzWbz6IOdELRt9mP2Pit6/pdrGbZLT9pEM=; b=bG1q5qUIKwf2h1gkiD6DYSpVQlIiX8nA3bbLSOH68fPRdD1ZZGbzCoZu568ZbuF+Yh olwGE3ayKAxiz8T4lexaVp1nkV/pkKapluBNqXezncoeUKmFKNg6WaAf+YOjLDZcheQ5 veCbLG0d5Jy5PaU9TtNWP8ZqBPKk6oAl/AoMXGnUMvu6vHeI6G1Jvlo+pTy1k0sVItbo wJEh3mpgAf+OLToY9RoprDMqciBc5a8GpPHwVlnNdQOGSrYts14UaqXkdNR6po+xXpBw Ju2YEy38wZEg5DRURg13zL5VmmLhJYIWb9CdYbaCt5BL4OtWATEdbkE9DqzBP/aKpO7O WiVQ== X-Gm-Message-State: AOAM533aZ6RKYyc2id+bBYgPDCy9OkTMmuP/LUPiFZmYnj0fCjT1VRbA tYpxXc3ve2N7Uh04PGJ6JZvVOwECtXmyJRqoO4s= X-Google-Smtp-Source: ABdhPJwFvflBXv1zO+yqsKDE+Q6hLPXgmAikrmT9l2k2PlDhnwYCmkg3AkrI1woqITjcFL1uLGVMbnf7bps3uuta3fE= X-Received: by 2002:a1c:2ec7:: with SMTP id u190mr26576269wmu.48.1593615551112; Wed, 01 Jul 2020 07:59:11 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Cliff Burdick Date: Wed, 1 Jul 2020 07:59:00 -0700 Message-ID: To: David Aldrich Cc: users Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: Re: [dpdk-users] Why is udp packet, sent by dpdk, received with zero'd payload? X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org Sender: "users" If you look at the code for rte_pktmbuf_prepend it appears to be just incrementing data_len and pkt_len by the same amount. My guess is that those fields were not set to the correct values before you called rte_pktmbuf_prepend(). On Wed, Jul 1, 2020 at 6:41 AM David Aldrich wrote: > I think this is where my lack of understanding is my problem. Looking at > the mbuf dump: > > dump mbuf at 0x53e4e92c0, iova=73e4e9340, buf_len=2176 > pkt_len=57, ol_flags=c0000000000000, nb_segs=2, in_port=65535 > segment at 0x53e4e92c0, data=0x53e4e9396, data_len=42 > Dump data at [0x53e4e9396], len=42 > 00000000: 94 40 C9 1F C4 DB 94 40 C9 1E 13 7D 08 00 45 B8 | .@.....@...}..E. > 00000010: 00 2B 00 00 00 00 40 11 F5 E8 C0 A8 01 69 C0 A8 | .+....@......i.. > 00000020: 01 68 0B B9 0B B8 00 17 64 2D | | | | | | | .h......d- > segment at 0x53e146e40, data=0x53e4fbbc0, data_len=15 > Dump data at [0x53e4fbbc0], len=15 > 00000000: 48 65 6C 6C 6F 20 66 72 6F 6D 20 64 70 64 6B | | Hello from dpdk > > It consists of two parts (segments?), of lengths 42 and 15. This makes sense to me as I first > put the payload in the mbuf (15 bytes) and then added the Ethernet and L3 headers (42 bytes) by calling rte_pktmbuf_prepend(). > > I guess only the first segment is getting transmitted? > > > On Wed, Jul 1, 2020 at 1:57 PM Cliff Burdick wrote: > >> Are you setting data_len and packet_len in the mbuf before sending? >> >> >> On Wed, Jul 1, 2020, 03:23 David Aldrich >> wrote: >> >>> Hi, >>> >>> I have a problem transmitting udp packets with dpdk-stable-18.11.8. I >>> have >>> posted a question about it on stackoverflow: >>> >>> >>> https://stackoverflow.com/questions/62674596/why-is-udp-packet-sent-by-dpdk-received-with-zerod-payload >>> >>> I would be grateful for any comments either there or in this group >>> please. >>> >>> Best regards >>> >>> David >>> >>