On 8/4/2023 9:28 AM, Kaiwen Deng wrote:
> IEEE 802 packets may have a minimum size limit. The data fields
> should be padded when necessary. In some cases, the padding data
> is not zero. Testpmd does not trim these IP packets to the true
> length of the frame, so errors will occur when calculating TCP
> or UDP checksum.
>
Hi Kaiwen,
I am trying to understand the problem, what is the testcase that has
checksum error?
Are the received mbuf data_len & pkt_len wrong? Instead of trying to fix
the mbuf during forwarding, can we fix where packet generated?
> This commit fixes this issue by triming IP packets to the true
> length of the frame in testpmd.
>
> Fixes: 03d17e4d0179 ("app/testpmd: do not change IP addrs in checksum engine")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Kaiwen Deng <kaiwenx.d...@intel.com>
> ---
> app/test-pmd/csumonly.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
> index 7af635e3f7..58b72b714a 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -853,12 +853,14 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
> uint16_t nb_rx;
> uint16_t nb_prep;
> uint16_t i;
> + uint16_t pad_len;
> uint64_t rx_ol_flags, tx_ol_flags;
> uint64_t tx_offloads;
> uint32_t rx_bad_ip_csum;
> uint32_t rx_bad_l4_csum;
> uint32_t rx_bad_outer_l4_csum;
> uint32_t rx_bad_outer_ip_csum;
> + uint32_t l3_off;
> struct testpmd_offload_info info;
>
> /* receive a burst of packet */
> @@ -980,6 +982,36 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
> l3_hdr = (char *)l3_hdr + info.outer_l3_len +
> info.l2_len;
> }
>
> + if (info.is_tunnel) {
> + l3_off = info.outer_l2_len +
> + info.outer_l3_len +
> + info.l2_len;
> + } else {
> + l3_off = info.l2_len;
> + }
> + switch (info.ethertype) {
> + case _htons(RTE_ETHER_TYPE_IPV4):
> + pad_len = rte_pktmbuf_data_len(m) -
> + (l3_off +
> + rte_be_to_cpu_16(
> + ((struct rte_ipv4_hdr
> *)l3_hdr)->total_length));
> + break;
> + case _htons(RTE_ETHER_TYPE_IPV6):
> + pad_len = rte_pktmbuf_data_len(m) -
> + (l3_off +
> + rte_be_to_cpu_16(
> + ((struct rte_ipv6_hdr
> *)l3_hdr)->payload_len));
> + break;
> + default:
> + pad_len = 0;
> + break;
> + }
> +
> + if (pad_len) {
> + rte_pktmbuf_data_len(m) = rte_pktmbuf_data_len(m) -
> pad_len;
> + rte_pktmbuf_pkt_len(m) = rte_pktmbuf_data_len(m);
> + }
> +
> /* step 2: depending on user command line configuration,
> * recompute checksum either in software or flag the
> * mbuf to offload the calculation to the NIC. If TSO
