RE: [PATCH v3] app/testpmd: perform SW IP checksum for GRO/GSO packets

["Hu, Jiayu" <jiayu.hu@intel.com>]

> -----Original Message-----
> From: Ma, WenwuX <wenwux.ma@intel.com>
> Sent: Thursday, May 12, 2022 9:08 AM
> To: Li, Xiaoyun <xiaoyun.li@intel.com>; Singh, Aman Deep
> <aman.deep.singh@intel.com>; Zhang, Yuying <yuying.zhang@intel.com>;
> dev@dpdk.org
> Cc: Hu, Jiayu <jiayu.hu@intel.com>; Wang, Yinan <yinan.wang@intel.com>;
> He, Xingguang <xingguang.he@intel.com>; Ma, WenwuX
> <wenwux.ma@intel.com>; stable@dpdk.org
> Subject: [PATCH v3] app/testpmd: perform SW IP checksum for GRO/GSO
> packets
> 
> The GRO/GSO library doesn't re-calculate checksums for merged/fragmented
> packets. If users want the packets to have correct IP checksums, they should
> select HW IP checksum calculation for the port which the packets are
> transmitted to. But if the port doesn't support HW IP checksum, users may
> perform a SW IP checksum. This patch add the code about it.
> 
> Fixes: b7091f1dcfbc ("app/testpmd: enable the heavyweight mode TCP/IPv4
> GRO")
> Fixes: 52f38a2055ed ("app/testpmd: enable TCP/IPv4 VxLAN and GRE GSO")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
> ---
>  app/test-pmd/csumonly.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c index
> 8b6665d6f3..2498ee88a2 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -778,6 +778,28 @@ pkt_copy_split(const struct rte_mbuf *pkt)
>  	return md[0];
>  }
> 
> +#if defined(RTE_LIB_GRO) || defined(RTE_LIB_GSO)
> +/*
> + * Re-calculate IP checksum for merged/fragmented packets.
> + */
> +static void
> +pkts_ip_csum_recalc(struct rte_mbuf **pkts_burst, const uint16_t
> +nb_pkts, uint64_t tx_offloads) {
> +	int i;
> +	struct rte_ipv4_hdr *ipv4_hdr;
> +	for (i = 0; i < nb_pkts; i++) {
> +		if ((pkts_burst[i]->ol_flags & RTE_MBUF_F_TX_IPV4) &&
> +			(tx_offloads & RTE_ETH_TX_OFFLOAD_IPV4_CKSUM)
> == 0) {
> +			ipv4_hdr = rte_pktmbuf_mtod_offset(pkts_burst[i],
> +						struct rte_ipv4_hdr *,
> +						pkts_burst[i]->l2_len);
> +			ipv4_hdr->hdr_checksum = 0;
> +			ipv4_hdr->hdr_checksum =
> rte_ipv4_cksum(ipv4_hdr);
> +		}
> +	}
> +}
> +#endif
> +
>  /*
>   * Receive a burst of packets, and for each packet:
>   *  - parse packet, and try to recognize a supported packet type (1) @@ -
> 1098,6 +1120,8 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>  				fs->gro_times = 0;
>  			}
>  		}
> +
> +		pkts_ip_csum_recalc(pkts_burst, nb_rx, tx_offloads);
>  	}
>  #endif
> 
> @@ -1131,6 +1155,8 @@ pkt_burst_checksum_forward(struct fwd_stream
> *fs)
> 
>  		tx_pkts_burst = gso_segments;
>  		nb_rx = nb_segments;
> +
> +		pkts_ip_csum_recalc(tx_pkts_burst, nb_rx, tx_offloads);
>  	} else
>  #endif
>  		tx_pkts_burst = pkts_burst;
> --
> 2.25.1

Reviewed-by: Jiayu Hu <jiayu.hu@intel.com>

Thanks,
Jiayu