From 982bb68cab2b93724f9625d53c309e73fa194e6e Mon Sep 17 00:00:00 2001 From: Hongzhi Guo Date: Fri, 10 Jul 2020 19:43:13 +0800 Subject: [PATCH] net: fix checksum on big endian CPUs MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit With current code, the checksum of odd-length buffers is wrong on big endian CPUs: the last byte is not properly summed to the accumulator. Fix this by left-shifting the remaining byte by 8. For instance, if the last byte is 0x42, we should add 0x4200 to the accumulator on big endian CPUs. This change is similar to what is suggested in Errata 3133 of RFC 1071. Fixes: 6006818cfb26("net: new checksum functions") Cc: stable@dpdk.org Signed-off-by: Hongzhi Guo Reviewed-by: Morten Brørup Acked-by: Olivier Matz --- lib/librte_net/rte_ip.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h index a9ffc33571..fcd1eb342d 100644 --- a/lib/librte_net/rte_ip.h +++ b/lib/librte_net/rte_ip.h @@ -139,8 +139,11 @@ __rte_raw_cksum(const void *buf, size_t len, uint32_t sum) } /* if length is in odd bytes */ - if (len == 1) - sum += *((const uint8_t *)u16_buf); + if (len == 1) { + uint16_t left = 0; + *(uint8_t *)&left = *(const uint8_t *)u16_buf; + sum += left; + } return sum; } -- 2.20.1