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 B20E8A0526; Fri, 10 Jul 2020 08:56:10 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id E58181DAF6; Fri, 10 Jul 2020 08:56:09 +0200 (CEST) Received: from huawei.com (szxga07-in.huawei.com [45.249.212.35]) by dpdk.org (Postfix) with ESMTP id 6C8431DAEC; Fri, 10 Jul 2020 08:56:08 +0200 (CEST) Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 5B39388CB07D59532AB9; Fri, 10 Jul 2020 14:56:05 +0800 (CST) Received: from DESKTOP-ORJPOMD.china.huawei.com (10.174.185.183) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.487.0; Fri, 10 Jul 2020 14:55:57 +0800 From: Hongzhi Guo To: CC: , , , , , , , , , , , , Date: Fri, 10 Jul 2020 14:55:51 +0800 Message-ID: <20200710065551.59352-1-guohongzhi1@huawei.com> X-Mailer: git-send-email 2.21.0.windows.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.174.185.183] X-CFilter-Loop: Reflected Subject: [dpdk-dev] [PATCH] net: fix unneeded replacement of 0 by ffff for TCP checksum X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Per RFC768: If the computed checksum is zero, it is transmitted as all ones. An all zero transmitted checksum value means that the transmitter generated no checksum. RFC793 for TCP has no such special treatment for the checksum of zero. Fixes: 6006818cfb26 ("net: new checksum functions") Cc: stable@dpdk.org Signed-off-by: Hongzhi Guo --- v2: * Fixed commit tile * Fixed the API comment --- --- lib/librte_net/rte_ip.h | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h index 292f63fd7..d03c77120 100644 --- a/lib/librte_net/rte_ip.h +++ b/lib/librte_net/rte_ip.h @@ -325,7 +325,7 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags) * The pointer to the beginning of the L4 header. * @return * The complemented checksum to set in the IP packet - * or 0 on error + * or 0 if the IP length is invalid in the header. */ static inline uint16_t rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr) @@ -344,7 +344,13 @@ rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr) cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff); cksum = (~cksum) & 0xffff; - if (cksum == 0) + /* + *Per RFC768: + *If the computed checksum is zero for udp, + *it is transmitted as all ones. + *(the equivalent in one's complement arithmetic). + */ + if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP) cksum = 0xffff; return (uint16_t)cksum; @@ -438,7 +444,13 @@ rte_ipv6_udptcp_cksum(const struct rte_ipv6_hdr *ipv6_hdr, const void *l4_hdr) cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff); cksum = (~cksum) & 0xffff; - if (cksum == 0) + /* + *Per RFC768: + *If the computed checksum is zero for udp, + *it is transmitted as all ones. + *(the equivalent in one's complement arithmetic). + */ + if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP) cksum = 0xffff; return (uint16_t)cksum; -- 2.21.0.windows.1