On Fri, Jul 10, 2020 at 02:55:51PM +0800, Hongzhi Guo wrote:
> 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: sta...@dpdk.org
>
> Signed-off-by: Hongzhi Guo <guohongz...@huawei.com>
> ---
> 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).
> + */
There should be a space after the '*', and maybe it could be on
less lines.
Thomas, maybe you can do it when applying?
> + 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).
> + */
Same here
> + if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP)
> cksum = 0xffff;
>
> return (uint16_t)cksum;
> --
> 2.21.0.windows.1
>
>
Acked-by: Olivier Matz <olivier.m...@6wind.com>
