Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 25 Feb 2002 22:54:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 25 Feb 2002 22:54:36 -0500 Received: from Hell.WH8.TU-Dresden.De ([141.30.225.3]:22789 "EHLO Hell.WH8.TU-Dresden.De") by vger.kernel.org with ESMTP id ; Mon, 25 Feb 2002 22:54:22 -0500 Message-ID: <3C7B06ED.8EC55523@delusion.de> Date: Tue, 26 Feb 2002 04:54:21 +0100 From: "Udo A. Steinberg" Organization: Disorganized X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.5.5 i686) X-Accept-Language: en, de MIME-Version: 1.0 To: Linux Kernel , linux-net Subject: mmapped packet socket queueing tcp packets twice? Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, While playing around with packet sockets I stumbled across the following strange thing: Feb 26 04:41:56 Kerberos ipacctd: [Slot 4] Incoming TCP - Len: 136 Sum: 72b7 [1014694916.161277] Feb 26 04:41:56 Kerberos ipacctd: [Slot 5] Incoming TCP - Len: 136 Sum: 72b7 [1014694916.161592] Feb 26 04:41:56 Kerberos ipacctd: [Slot 9] Incoming TCP - Len: 120 Sum: 81b7 [1014694916.168418] Feb 26 04:41:56 Kerberos ipacctd: [Slot 10] Incoming TCP - Len: 120 Sum: 81b7 [1014694916.168687] Feb 26 04:41:56 Kerberos ipacctd: [Slot 12] Incoming TCP - Len: 120 Sum: 80b7 [1014694916.170024] Feb 26 04:41:56 Kerberos ipacctd: [Slot 13] Incoming TCP - Len: 120 Sum: 80b7 [1014694916.170283] Feb 26 04:41:56 Kerberos ipacctd: [Slot 15] Incoming TCP - Len: 120 Sum: 7fb7 [1014694916.171432] Feb 26 04:41:56 Kerberos ipacctd: [Slot 16] Incoming TCP - Len: 120 Sum: 7fb7 [1014694916.171681] Feb 26 04:41:56 Kerberos ipacctd: [Slot 18] Incoming TCP - Len: 120 Sum: 7eb7 [1014694916.172807] Feb 26 04:41:56 Kerberos ipacctd: [Slot 19] Incoming TCP - Len: 120 Sum: 7eb7 [1014694916.173094] Feb 26 04:41:56 Kerberos ipacctd: [Slot 21] Incoming TCP - Len: 120 Sum: 7db7 [1014694916.174245] Feb 26 04:41:56 Kerberos ipacctd: [Slot 22] Incoming TCP - Len: 120 Sum: 7db7 [1014694916.174499] Feb 26 04:41:56 Kerberos ipacctd: [Slot 24] Incoming TCP - Len: 120 Sum: 7cb7 [1014694916.176289] Feb 26 04:41:56 Kerberos ipacctd: [Slot 25] Incoming TCP - Len: 120 Sum: 7cb7 [1014694916.176562] Feb 26 04:41:56 Kerberos ipacctd: [Slot 30] Incoming TCP - Len: 136 Sum: 6bb7 [1014694916.182037] Feb 26 04:41:56 Kerberos ipacctd: [Slot 31] Incoming TCP - Len: 136 Sum: 6bb7 [1014694916.182308] ^ ^ ^ | | | Ring Slot Checksum Timestamp The program runs under Linux-2.4.17 on machine A and looks for packets of type PACKET_OTHERHOST coming from and going to machine B. For all incoming tcp traffic of machine B, each packet appears in the mmapped packet ring twice. The ring slots are adjacent and the checksum is the same. Only the timestamps differ slightly. Can someone explain this behaviour? -Udo. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/