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 E39B7A046B; Sat, 9 May 2020 10:24:37 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id BE6D91D706; Sat, 9 May 2020 10:24:37 +0200 (CEST) Received: from huawei.com (szxga05-in.huawei.com [45.249.212.191]) by dpdk.org (Postfix) with ESMTP id B41571D705 for ; Sat, 9 May 2020 10:24:35 +0200 (CEST) Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id E2F43F23578B51544977; Sat, 9 May 2020 16:24:33 +0800 (CST) Received: from DESKTOP-ORJPOMD.china.huawei.com (10.173.251.143) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.487.0; Sat, 9 May 2020 16:24:27 +0800 From: guohongzhi To: CC: , , , , , Date: Sat, 9 May 2020 16:24:21 +0800 Message-ID: <20200509082421.24588-1-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: [10.173.251.143] X-CFilter-Loop: Reflected Subject: [dpdk-dev] [PATCH] [PATCH] lib/librte_net: fix bug for ipv4 checksum calculating 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" The function of rte_ipv4_cksum for calculating the checksum of IPv4 header is incorrect. This function will return checksum value like 0xffff. This value, however, is considered an illegal checksum on some switches(like Trident3). RFC 1624 specifies the IPv4 checksum as follows: https://tools.ietf.org/rfc/rfc1624 Since there is guaranteed to be at least one non-zero field in the IP header, and the checksum field in the protocol header is the complement of the sum, the checksum field can never contain ~(+0), which is -0 (0xFFFF). It can, however, contain ~(-0), which is +0 (0x0000). --- lib/librte_net/rte_ip.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h index 1ceb7b7..ece2e43 100644 --- a/lib/librte_net/rte_ip.h +++ b/lib/librte_net/rte_ip.h @@ -267,7 +267,7 @@ rte_ipv4_cksum(const struct rte_ipv4_hdr *ipv4_hdr) { uint16_t cksum; cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr)); - return (cksum == 0xffff) ? cksum : (uint16_t)~cksum; + return (uint16_t)~cksum; } /** -- 2.21.0.windows.1