Hi
> -----Original Message-----
> From: Gregory Etelson <getel...@nvidia.com>
> Sent: Tuesday, July 27, 2021 21:08
> To: dev@dpdk.org
> Cc: getel...@nvidia.com; Ajit Khaparde <ajit.khapa...@broadcom.com>;
> Olivier Matz <olivier.m...@6wind.com>; Andrew Rybchenko
> <andrew.rybche...@oktetlabs.ru>; Yigit, Ferruh <ferruh.yi...@intel.com>;
> Thomas Monjalon <tho...@monjalon.net>; sta...@dpdk.org; Li, Xiaoyun
> <xiaoyun...@intel.com>
> Subject: [PATCH v2] app/testpmd: fix TX checksum calculation for tunnel
>
> TX checksum of a tunnelled packet can be calculated for outer headers only or
> for both outer and inner parts. The calculation method is determined by
> application.
> If TX checksum calculation can be offloaded, hardware ignores existing
> checksum value and replaces it with an updated result.
> If TX checksum is calculated by a software, existing value must be zeroed
> first.
> The testpmd checksum forwarding engine always zeroed inner checksums.
> If inner checksum calculation was offloaded, that header was left with 0
> checksum value.
> Following outer software checksum calculation produced wrong value.
> The patch zeroes inner IPv4 checksum only before software calculation.
>
> Fixes: 51f694dd40f5 ("app/testpmd: rework checksum forward engine")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Gregory Etelson <getel...@nvidia.com>
> ---
> v2:
> remove blank line between Fixes and Cc
> explicitly compare with 0 value in `if ()`
> ---
> app/test-pmd/csumonly.c | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c index
> 0161f72175..bd5ad64a57 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -480,17 +480,18 @@ process_inner_cksums(void *l3_hdr, const struct
> testpmd_offload_info *info,
>
> if (info->ethertype == _htons(RTE_ETHER_TYPE_IPV4)) {
> ipv4_hdr = l3_hdr;
> - ipv4_hdr->hdr_checksum = 0;
>
> ol_flags |= PKT_TX_IPV4;
> if (info->l4_proto == IPPROTO_TCP && tso_segsz) {
> ol_flags |= PKT_TX_IP_CKSUM;
> } else {
> - if (tx_offloads & DEV_TX_OFFLOAD_IPV4_CKSUM)
> + if (tx_offloads & DEV_TX_OFFLOAD_IPV4_CKSUM) {
> ol_flags |= PKT_TX_IP_CKSUM;
> - else
> + } else if (ipv4_hdr->hdr_checksum != 0) {
> + ipv4_hdr->hdr_checksum = 0;
> ipv4_hdr->hdr_checksum =
> rte_ipv4_cksum(ipv4_hdr);
> + }
> }
> } else if (info->ethertype == _htons(RTE_ETHER_TYPE_IPV6))
> ol_flags |= PKT_TX_IPV6;
> @@ -501,10 +502,10 @@ process_inner_cksums(void *l3_hdr, const struct
> testpmd_offload_info *info,
> udp_hdr = (struct rte_udp_hdr *)((char *)l3_hdr + info->l3_len);
> /* do not recalculate udp cksum if it was 0 */
> if (udp_hdr->dgram_cksum != 0) {
> - udp_hdr->dgram_cksum = 0;
> - if (tx_offloads & DEV_TX_OFFLOAD_UDP_CKSUM)
> + if (tx_offloads & DEV_TX_OFFLOAD_UDP_CKSUM) {
> ol_flags |= PKT_TX_UDP_CKSUM;
> - else {
> + } else {
else if (udp_hdr->dgram_cksum != 0) { ?
> + udp_hdr->dgram_cksum = 0;
> udp_hdr->dgram_cksum =
> get_udptcp_checksum(l3_hdr, udp_hdr,
> info->ethertype);
> @@ -514,12 +515,12 @@ process_inner_cksums(void *l3_hdr, const struct
> testpmd_offload_info *info,
> ol_flags |= PKT_TX_UDP_SEG;
> } else if (info->l4_proto == IPPROTO_TCP) {
> tcp_hdr = (struct rte_tcp_hdr *)((char *)l3_hdr + info->l3_len);
> - tcp_hdr->cksum = 0;
> if (tso_segsz)
> ol_flags |= PKT_TX_TCP_SEG;
> - else if (tx_offloads & DEV_TX_OFFLOAD_TCP_CKSUM)
> + else if (tx_offloads & DEV_TX_OFFLOAD_TCP_CKSUM) {
> ol_flags |= PKT_TX_TCP_CKSUM;
> - else {
> + } else if (tcp_hdr->cksum != 0) {
> + tcp_hdr->cksum = 0;
> tcp_hdr->cksum =
> get_udptcp_checksum(l3_hdr, tcp_hdr,
> info->ethertype);
> @@ -529,13 +530,13 @@ process_inner_cksums(void *l3_hdr, const struct
> testpmd_offload_info *info,
> } else if (info->l4_proto == IPPROTO_SCTP) {
> sctp_hdr = (struct rte_sctp_hdr *)
> ((char *)l3_hdr + info->l3_len);
> - sctp_hdr->cksum = 0;
> /* sctp payload must be a multiple of 4 to be
> * offloaded */
> if ((tx_offloads & DEV_TX_OFFLOAD_SCTP_CKSUM) &&
> ((ipv4_hdr->total_length & 0x3) == 0)) {
> ol_flags |= PKT_TX_SCTP_CKSUM;
> - } else {
> + } else if (sctp_hdr->cksum != 0) {
> + sctp_hdr->cksum = 0;
> /* XXX implement CRC32c, example available in
> * RFC3309 */
> }
> --
> 2.32.0
