On Thu, 8 Jan 2026 16:47:13 -0500
[email protected] wrote:
> diff --git a/lib/net/rte_ip6.h b/lib/net/rte_ip6.h
> index d1abf1f5d5..8a7e5e4b8a 100644
> --- a/lib/net/rte_ip6.h
> +++ b/lib/net/rte_ip6.h
> @@ -560,19 +560,18 @@ rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr
> *ipv6_hdr, uint64_t ol_flags)
> static inline uint16_t
> rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags)
> {
> - uint32_t sum;
> struct {
> rte_be32_t len; /* L4 length. */
> rte_be32_t proto; /* L4 protocol - top 3 bytes must be zero */
> - } psd_hdr;
> -
> - psd_hdr.proto = (uint32_t)(ipv6_hdr->proto << 24);
> - if (ol_flags & (RTE_MBUF_F_TX_TCP_SEG | RTE_MBUF_F_TX_UDP_SEG))
> - psd_hdr.len = 0;
> - else
> - psd_hdr.len = ipv6_hdr->payload_len;
> + } psd_hdr = {
> + .len = (ol_flags & (RTE_MBUF_F_TX_TCP_SEG |
> RTE_MBUF_F_TX_UDP_SEG))
> + ? (rte_be32_t)0
> + : ipv6_hdr->payload_len,
> + .proto = (uint32_t)(ipv6_hdr->proto << 24)
> + };
> + RTE_SUPPRESS_UNINITIALIZED_WARNING(psd_hdr);
>
> - sum = __rte_raw_cksum(&ipv6_hdr->src_addr,
> + uint32_t sum = __rte_raw_cksum(&ipv6_hdr->src_addr,
> sizeof(ipv6_hdr->src_addr) + sizeof(ipv6_hdr->dst_addr),
> 0);
> sum = __rte_raw_cksum(&psd_hdr, sizeof(psd_hdr), sum);
> --
Seems like this could be unrolled as well.
static inline uint16_t
rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags)
{
union {
struct {
struct rte_ipv6_addr src_addr; /* 16 bytes */
struct rte_ipv6_addr dst_addr; /* 16 bytes */
rte_be32_t len; /* 4 bytes */
rte_be32_t proto; /* 4 bytes */
} psd;
uint16_t u16[20];
} hdr = {
.psd = {
.src_addr = ipv6_hdr->src_addr,
.dst_addr = ipv6_hdr->dst_addr,
.proto = (uint32_t)(ipv6_hdr->proto << 24),
}
};
uint32_t sum;
if (!(ol_flags & (RTE_MBUF_F_TX_TCP_SEG | RTE_MBUF_F_TX_UDP_SEG)))
hdr.psd.len = ipv6_hdr->payload_len;
/* Unrolled sum of 20 uint16_t words:
* [0-7]: src_addr
* [8-15]: dst_addr
* [16-17]: len
* [18-19]: proto (3 zero bytes + next header)
*/
sum = hdr.u16[0] + hdr.u16[1] + hdr.u16[2] + hdr.u16[3] +
hdr.u16[4] + hdr.u16[5] + hdr.u16[6] + hdr.u16[7] +
hdr.u16[8] + hdr.u16[9] + hdr.u16[10] + hdr.u16[11] +
hdr.u16[12] + hdr.u16[13] + hdr.u16[14] + hdr.u16[15] +
hdr.u16[16] + hdr.u16[17] + hdr.u16[18] + hdr.u16[19];
sum = (sum & 0xffff) + (sum >> 16);
sum = (sum & 0xffff) + (sum >> 16);
return (uint16_t)sum;
}
