From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <jianfeng.tan@intel.com> Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 20233330D for <dev@dpdk.org>; Sat, 8 Jul 2017 18:37:48 +0200 (CEST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jul 2017 09:37:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,329,1496127600"; d="scan'208";a="284549174" Received: from tanjianf-mobl.ccr.corp.intel.com (HELO [10.255.31.104]) ([10.255.31.104]) by fmsmga004.fm.intel.com with ESMTP; 08 Jul 2017 09:37:46 -0700 To: Jiayu Hu <jiayu.hu@intel.com>, dev@dpdk.org References: <1499227716-116583-1-git-send-email-jiayu.hu@intel.com> <1499423958-84024-1-git-send-email-jiayu.hu@intel.com> <1499423958-84024-3-git-send-email-jiayu.hu@intel.com> Cc: konstantin.ananyev@intel.com, yliu@fridaylinux.org, stephen@networkplumber.org, jingjing.wu@intel.com, lei.a.yao@intel.com From: "Tan, Jianfeng" <jianfeng.tan@intel.com> Message-ID: <1d1750da-5118-9949-888b-3887d9c5de46@intel.com> Date: Sun, 9 Jul 2017 00:37:46 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1499423958-84024-3-git-send-email-jiayu.hu@intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v12 2/3] lib/gro: add TCP/IPv4 GRO support X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Sat, 08 Jul 2017 16:37:49 -0000 On 7/7/2017 6:39 PM, Jiayu Hu wrote: > In this patch, we introduce five APIs to support TCP/IPv4 GRO. > - gro_tcp4_reassemble: reassemble an inputted TCP/IPv4 packet. > - gro_tcp4_tbl_create: create a TCP/IPv4 reassembly table, which is used > to merge packets. > - gro_tcp4_tbl_destroy: free memory space of a TCP/IPv4 reassembly table. > - gro_tcp4_tbl_pkt_count: return the number of packets in a TCP/IPv4 > reassembly table. > - gro_tcp4_tbl_timeout_flush: flush timeout packets from a TCP/IPv4 > reassembly table. > > TCP/IPv4 GRO API assumes all inputted packets are with correct IPv4 > and TCP checksums. And TCP/IPv4 GRO API doesn't update IPv4 and TCP > checksums for merged packets. If inputted packets are IP fragmented, > TCP/IPv4 GRO API assumes they are complete packets (i.e. with L4 > headers). > > In TCP/IPv4 GRO, we use a table structure, called TCP/IPv4 reassembly > table, to reassemble packets. A TCP/IPv4 reassembly table includes a key > array and a item array, where the key array keeps the criteria to merge > packets and the item array keeps packet information. > > One key in the key array points to an item group, which consists of > packets which have the same criteria value. If two packets are able to > merge, they must be in the same item group. Each key in the key array > includes two parts: > - criteria: the criteria of merging packets. If two packets can be > merged, they must have the same criteria value. > - start_index: the index of the first incoming packet of the item group. > > Each element in the item array keeps the information of one packet. It > mainly includes three parts: > - firstseg: the address of the first segment of the packet > - lastseg: the address of the last segment of the packet > - next_pkt_index: the index of the next packet in the same item group. > All packets in the same item group are chained by next_pkt_index. > With next_pkt_index, we can locate all packets in the same item > group one by one. > > To process an incoming packet needs three steps: > a. check if the packet should be processed. Packets with one of the > following properties won't be processed: > - FIN, SYN, RST, URG, PSH, ECE or CWR bit is set; > - packet payload length is 0. > b. traverse the key array to find a key which has the same criteria > value with the incoming packet. If find, goto step c. Otherwise, > insert a new key and insert the packet into the item array. > c. locate the first packet in the item group via the start_index in the > key. Then traverse all packets in the item group via next_pkt_index. > If find one packet which can merge with the incoming one, merge them > together. If can't find, insert the packet into this item group. > > Signed-off-by: Jiayu Hu <jiayu.hu@intel.com> Reviewed-by: Jianfeng Tan <jianfeng.tan@intel.com>