Re: [dpdk-dev] [PATCH] lib/librte_net: fix bug for checksum calculating

["Morten Brørup" <mb@smartsharesystems.com>]

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of guohongzhi
> Sent: Friday, May 15, 2020 3:09 PM
> 
> 1.rte_ipv4_cksum will return invalid checksum value like
> 0xffff.(rfc1624)
> 2.__rte_raw_cksum should consider Big Endian.
> 3.checksum 0x0000 is invalid for udp, but valid for tcp.(rfc768)
> 
> Signed-off-by: guohongzhi <guohongzhi1@huawei.com>
> ---
>  lib/librte_net/rte_ip.h | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
> index 1ceb7b7..4177ea7 100644
> --- a/lib/librte_net/rte_ip.h
> +++ b/lib/librte_net/rte_ip.h
> @@ -140,7 +140,11 @@ __rte_raw_cksum(const void *buf, size_t len,
> uint32_t sum)
> 
>  	/* if length is in odd bytes */
>  	if (len == 1)
> +#if (RTE_BYTE_ORDER == RTE_BIG_ENDIAN)
> +		sum += *((const uint8_t *)u16_buf) << 8;
> +#else
>  		sum += *((const uint8_t *)u16_buf);
> +#endif
> 
>  	return sum;
>  }
> @@ -267,7 +271,7 @@ 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;
>  }
> 
>  /**
> @@ -324,8 +328,7 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr
> *ipv4_hdr, uint64_t ol_flags)
>   * @param l4_hdr
>   *   The pointer to the beginning of the L4 header.
>   * @return
> - *   The complemented checksum to set in the IP packet
> - *   or 0 on error
> + *   The complemented checksum to set in the IP packet.
>   */
>  static inline uint16_t
>  rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void
> *l4_hdr)
> @@ -344,7 +347,8 @@ 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)
> +	/* 0x0000 is invalid for udp, but valid for tcp. rfc768 */
> +	if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
>  		cksum = 0xffff;
> 
>  	return (uint16_t)cksum;
> @@ -436,7 +440,8 @@ 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)
> +	/* 0x0000 is invalid for udp, but valid for tcp. rfc768 */
> +	if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP)
>  		cksum = 0xffff;
> 
>  	return (uint16_t)cksum;
> --
> 2.21.0.windows.1
> 
> 

Reviewed-by: Morten Brørup <mb@smartsharesystems.com>