<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:DengXian;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"\@DengXian";
panose-1:2 1 6 0 3 1 1 1 1 1;}
/* Style Definitions */
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{mso-style-priority:99;
mso-style-link:"Plain Text Char";
margin:0cm;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.PlainTextChar
{mso-style-name:"Plain Text Char";
mso-style-priority:99;
mso-style-link:"Plain Text";
font-family:"Calibri",sans-serif;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoPlainText">> -----Original Message-----<br>
> From: <span lang="ZH-CN" style="font-family:DengXian">苏赛</span> <susai.ss@bytedance.com>
<o:p></o:p></p>
<p class="MsoPlainText">> Sent: Thursday 31 July 2025 10:55<o:p></o:p></p>
<p class="MsoPlainText">> To: jasvinder.singh@intel.com<o:p></o:p></p>
<p class="MsoPlainText">> Cc: dev@dpdk.org<o:p></o:p></p>
<p class="MsoPlainText">> Subject: [PATCH] net/cksum: compute raw cksum for several segments<o:p></o:p></p>
<p class="MsoPlainText">> <o:p></o:p></p>
<p class="MsoPlainText">> The rte_raw_cksum_mbuf function is used to compute<o:p></o:p></p>
<p class="MsoPlainText">> the raw checksum of a packet.<o:p></o:p></p>
<p class="MsoPlainText">> If the packet payload stored in multi mbuf, the function<o:p></o:p></p>
<p class="MsoPlainText">> will goto the hard case. In hard case,<o:p></o:p></p>
<p class="MsoPlainText">> the variable 'tmp' is a type of uint32_t,<o:p></o:p></p>
<p class="MsoPlainText">> so rte_bswap16 will drop high 16 bit.<o:p></o:p></p>
<p class="MsoPlainText">> Meanwhile, the variable 'sum' is a type of uint32_t,<o:p></o:p></p>
<p class="MsoPlainText">> so 'sum += tmp' will drop the carry when overflow.<o:p></o:p></p>
<p class="MsoPlainText">> Both drop will make cksum incorrect.<o:p></o:p></p>
<p class="MsoPlainText">> This commit fixes the above bug.<o:p></o:p></p>
<p class="MsoPlainText">> <o:p></o:p></p>
<p class="MsoPlainText">> Signed-off-by: Su Sai <susai.ss@bytedance.com><o:p></o:p></p>
<p class="MsoPlainText">> ---<o:p></o:p></p>
<p class="MsoPlainText">> .mailmap | 1 +<o:p></o:p></p>
<p class="MsoPlainText">> lib/net/rte_cksum.h | 26 +++++++++++++++++++++++---<o:p></o:p></p>
<p class="MsoPlainText">> 2 files changed, 24 insertions(+), 3 deletions(-)<o:p></o:p></p>
<p class="MsoPlainText">> <o:p></o:p></p>
<p class="MsoPlainText">> diff --git a/.mailmap b/.mailmap<o:p></o:p></p>
<p class="MsoPlainText">> index 34a99f93a1..838b544a97 100644<o:p></o:p></p>
<p class="MsoPlainText">> --- a/.mailmap<o:p></o:p></p>
<p class="MsoPlainText">> +++ b/.mailmap<o:p></o:p></p>
<p class="MsoPlainText">> @@ -1891,3 +1891,4 @@ Zoltan Kiss <zoltan.kiss@schaman.hu> <zoltan.kiss@linaro.org><o:p></o:p></p>
<p class="MsoPlainText">> Zorik Machulsky <zorik@amazon.com><o:p></o:p></p>
<p class="MsoPlainText">> Zyta Szpak <zyta@marvell.com> <zr@semihalf.com><o:p></o:p></p>
<p class="MsoPlainText">> Zyta Szpak <zyta@marvell.com> <zyta.szpak@semihalf.com><o:p></o:p></p>
<p class="MsoPlainText">> +Su Sai <susai.ss@bytedance.com><o:p></o:p></p>
<p class="MsoPlainText">> diff --git a/lib/net/rte_cksum.h b/lib/net/rte_cksum.h<o:p></o:p></p>
<p class="MsoPlainText">> index a8e8927952..aa584d5f8d 100644<o:p></o:p></p>
<p class="MsoPlainText">> --- a/lib/net/rte_cksum.h<o:p></o:p></p>
<p class="MsoPlainText">> +++ b/lib/net/rte_cksum.h<o:p></o:p></p>
<p class="MsoPlainText">> @@ -80,6 +80,25 @@ __rte_raw_cksum_reduce(uint32_t sum)<o:p></o:p></p>
<p class="MsoPlainText">> return (uint16_t)sum;<o:p></o:p></p>
<p class="MsoPlainText">> }<o:p></o:p></p>
<p class="MsoPlainText">> <o:p></o:p></p>
<p class="MsoPlainText">> +/**<o:p></o:p></p>
<p class="MsoPlainText">> + * @internal Reduce a sum to the non-complemented checksum.<o:p></o:p></p>
<p class="MsoPlainText">> + * Helper routine for the rte_raw_cksum_mbuf().<o:p></o:p></p>
<p class="MsoPlainText">> + *<o:p></o:p></p>
<p class="MsoPlainText">> + * @param sum<o:p></o:p></p>
<p class="MsoPlainText">> + * Value of the sum.<o:p></o:p></p>
<p class="MsoPlainText">> + * @return<o:p></o:p></p>
<p class="MsoPlainText">> + * The non-complemented checksum.<o:p></o:p></p>
<p class="MsoPlainText">> + */<o:p></o:p></p>
<p class="MsoPlainText">> +static inline uint16_t<o:p></o:p></p>
<p class="MsoPlainText">> +__rte_raw_cksum_reduce_u64(uint64_t sum)<o:p></o:p></p>
<p class="MsoPlainText">> +{<o:p></o:p></p>
<p class="MsoPlainText">> + uint32_t tmp;<o:p></o:p></p>
<p class="MsoPlainText">> +<o:p></o:p></p>
<p class="MsoPlainText">> + tmp = __rte_raw_cksum_reduce((uint32_t)sum);<o:p></o:p></p>
<p class="MsoPlainText">> + tmp += __rte_raw_cksum_reduce((uint32_t)(sum >> 32));<o:p></o:p></p>
<p class="MsoPlainText">> + return __rte_raw_cksum_reduce(tmp);<o:p></o:p></p>
<p class="MsoPlainText">> +}<o:p></o:p></p>
<p class="MsoPlainText">> +<o:p></o:p></p>
<p class="MsoPlainText">> /**<o:p></o:p></p>
<p class="MsoPlainText">> * Process the non-complemented checksum of a buffer.<o:p></o:p></p>
<p class="MsoPlainText">> *<o:p></o:p></p>
<p class="MsoPlainText">> @@ -119,8 +138,9 @@ rte_raw_cksum_mbuf(const struct rte_mbuf *m, uint32_t off, uint32_t len,<o:p></o:p></p>
<p class="MsoPlainText">> {<o:p></o:p></p>
<p class="MsoPlainText">> const struct rte_mbuf *seg;<o:p></o:p></p>
<p class="MsoPlainText">> const char *buf;<o:p></o:p></p>
<p class="MsoPlainText">> - uint32_t sum, tmp;<o:p></o:p></p>
<p class="MsoPlainText">> + uint32_t tmp;<o:p></o:p></p>
<p class="MsoPlainText">> uint32_t seglen, done;<o:p></o:p></p>
<p class="MsoPlainText">> + uint64_t sum;<o:p></o:p></p>
<p class="MsoPlainText">> <o:p></o:p></p>
<p class="MsoPlainText">> /* easy case: all data in the first segment */<o:p></o:p></p>
<p class="MsoPlainText">> if (off + len <= rte_pktmbuf_data_len(m)) {<o:p></o:p></p>
<p class="MsoPlainText">> @@ -157,7 +177,7 @@ rte_raw_cksum_mbuf(const struct rte_mbuf *m, uint32_t off, uint32_t len,<o:p></o:p></p>
<p class="MsoPlainText">> for (;;) {<o:p></o:p></p>
<p class="MsoPlainText">> tmp = __rte_raw_cksum(buf, seglen, 0);<o:p></o:p></p>
<p class="MsoPlainText">> if (done & 1)<o:p></o:p></p>
<p class="MsoPlainText">> - tmp = rte_bswap16((uint16_t)tmp);<o:p></o:p></p>
<p class="MsoPlainText">> + tmp = rte_bswap32(tmp);<o:p></o:p></p>
<p class="MsoPlainText">> sum += tmp;<o:p></o:p></p>
<p class="MsoPlainText">> done += seglen;<o:p></o:p></p>
<p class="MsoPlainText">> if (done == len)<o:p></o:p></p>
<p class="MsoPlainText">> @@ -169,7 +189,7 @@ rte_raw_cksum_mbuf(const struct rte_mbuf *m, uint32_t off, uint32_t len,<o:p></o:p></p>
<p class="MsoPlainText">> seglen = len - done;<o:p></o:p></p>
<p class="MsoPlainText">> }<o:p></o:p></p>
<p class="MsoPlainText">> <o:p></o:p></p>
<p class="MsoPlainText">> - *cksum = __rte_raw_cksum_reduce(sum);<o:p></o:p></p>
<p class="MsoPlainText">> + *cksum = __rte_raw_cksum_reduce_u64(sum);<o:p></o:p></p>
<p class="MsoPlainText">> return 0;<o:p></o:p></p>
<p class="MsoPlainText">> }<o:p></o:p></p>
<p class="MsoPlainText">> <o:p></o:p></p>
<p class="MsoPlainText">> -- <o:p></o:p></p>
<p class="MsoPlainText">> 2.39.2 (Apple Git-143)<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Acked-by: Marat Khalili <<a href="mailto:marat.khalili@huawei.com">marat.khalili@huawei.com</a>><o:p></o:p></p>
</div>
</body>
</html>