Re: [PATCH v5 2/2] testpmd: fix l4 sw csum over multi segments

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 1/6/2022 4:03 PM, Xiaoyun Li wrote:
> In csum forwarding mode, software UDP/TCP csum calculation only takes
> the first segment into account while using the whole packet length so
> the calculation will read invalid memory region with multi-segments
> packets and will get wrong value.
> This patch fixes this issue.
> 
> Signed-off-by: Xiaoyun Li <xiaoyun.li@intel.com>
> Tested-by: Sunil Pai G <sunil.pai.g@intel.com>

Can you please check following check-git-log.sh warnings:

./devtools/check-git-log.sh -2
Wrong headline label:
         testpmd: fix l4 sw csum over multi segments
Wrong headline case:
                         "testpmd: fix l4 sw csum over multi segments": l4 --> L4
Wrong headline case:
                         "testpmd: fix l4 sw csum over multi segments": sw --> SW
Missing 'Fixes' tag:
         testpmd: fix l4 sw csum over multi segments



> ---
>   app/test-pmd/csumonly.c | 41 ++++++++++++++++++++++++++---------------
>   1 file changed, 26 insertions(+), 15 deletions(-)
> 
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
> index 2aeea243b6..0fbe1f1be7 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -96,12 +96,13 @@ struct simple_gre_hdr {
>   } __rte_packed;
>   
>   static uint16_t
> -get_udptcp_checksum(void *l3_hdr, void *l4_hdr, uint16_t ethertype)
> +get_udptcp_checksum(struct rte_mbuf *m, void *l3_hdr, uint16_t l4_off,
> +		    uint16_t ethertype)
>   {
>   	if (ethertype == _htons(RTE_ETHER_TYPE_IPV4))
> -		return rte_ipv4_udptcp_cksum(l3_hdr, l4_hdr);
> +		return rte_ipv4_udptcp_cksum_mbuf(m, l3_hdr, l4_off);
>   	else /* assume ethertype == RTE_ETHER_TYPE_IPV6 */
> -		return rte_ipv6_udptcp_cksum(l3_hdr, l4_hdr);
> +		return rte_ipv6_udptcp_cksum_mbuf(m, l3_hdr, l4_off);
>   }
>   
>   /* Parse an IPv4 header to fill l3_len, l4_len, and l4_proto */
> @@ -460,7 +461,7 @@ parse_encap_ip(void *encap_ip, struct testpmd_offload_info *info)
>    * depending on the testpmd command line configuration */
>   static uint64_t
>   process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
> -	uint64_t tx_offloads)
> +	uint64_t tx_offloads, struct rte_mbuf *m)
>   {
>   	struct rte_ipv4_hdr *ipv4_hdr = l3_hdr;
>   	struct rte_udp_hdr *udp_hdr;
> @@ -468,6 +469,7 @@ process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
>   	struct rte_sctp_hdr *sctp_hdr;
>   	uint64_t ol_flags = 0;
>   	uint32_t max_pkt_len, tso_segsz = 0;
> +	uint16_t l4_off;
>   
>   	/* ensure packet is large enough to require tso */
>   	if (!info->is_tunnel) {
> @@ -510,9 +512,15 @@ process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
>   			if (tx_offloads & RTE_ETH_TX_OFFLOAD_UDP_CKSUM) {
>   				ol_flags |= RTE_MBUF_F_TX_UDP_CKSUM;
>   			} else {
> +				if (info->is_tunnel)
> +					l4_off = info->l2_len +
> +						 info->outer_l3_len +
> +						 info->l2_len + info->l3_len;
> +				else
> +					l4_off = info->l2_len +	info->l3_len;
>   				udp_hdr->dgram_cksum = 0;
>   				udp_hdr->dgram_cksum =
> -					get_udptcp_checksum(l3_hdr, udp_hdr,
> +					get_udptcp_checksum(m, l3_hdr, l4_off,
>   						info->ethertype);
>   			}
>   		}
> @@ -527,9 +535,14 @@ process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
>   		else if (tx_offloads & RTE_ETH_TX_OFFLOAD_TCP_CKSUM) {
>   			ol_flags |= RTE_MBUF_F_TX_TCP_CKSUM;
>   		} else {
> +			if (info->is_tunnel)
> +				l4_off = info->l2_len + info->outer_l3_len +
> +					 info->l2_len + info->l3_len;
> +			else
> +				l4_off = info->l2_len + info->l3_len;
>   			tcp_hdr->cksum = 0;
>   			tcp_hdr->cksum =
> -				get_udptcp_checksum(l3_hdr, tcp_hdr,
> +				get_udptcp_checksum(m, l3_hdr, l4_off,
>   					info->ethertype);
>   		}
>   #ifdef RTE_LIB_GSO
> @@ -557,7 +570,7 @@ process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
>   /* Calculate the checksum of outer header */
>   static uint64_t
>   process_outer_cksums(void *outer_l3_hdr, struct testpmd_offload_info *info,
> -	uint64_t tx_offloads, int tso_enabled)
> +	uint64_t tx_offloads, int tso_enabled, struct rte_mbuf *m)
>   {
>   	struct rte_ipv4_hdr *ipv4_hdr = outer_l3_hdr;
>   	struct rte_ipv6_hdr *ipv6_hdr = outer_l3_hdr;
> @@ -611,12 +624,9 @@ process_outer_cksums(void *outer_l3_hdr, struct testpmd_offload_info *info,
>   	/* do not recalculate udp cksum if it was 0 */
>   	if (udp_hdr->dgram_cksum != 0) {
>   		udp_hdr->dgram_cksum = 0;
> -		if (info->outer_ethertype == _htons(RTE_ETHER_TYPE_IPV4))
> -			udp_hdr->dgram_cksum =
> -				rte_ipv4_udptcp_cksum(ipv4_hdr, udp_hdr);
> -		else
> -			udp_hdr->dgram_cksum =
> -				rte_ipv6_udptcp_cksum(ipv6_hdr, udp_hdr);
> +		udp_hdr->dgram_cksum = get_udptcp_checksum(m, outer_l3_hdr,
> +					info->l2_len + info->outer_l3_len,
> +					info->outer_ethertype);
>   	}
>   
>   	return ol_flags;
> @@ -957,7 +967,7 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>   
>   		/* process checksums of inner headers first */
>   		tx_ol_flags |= process_inner_cksums(l3_hdr, &info,
> -			tx_offloads);
> +			tx_offloads, m);
>   
>   		/* Then process outer headers if any. Note that the software
>   		 * checksum will be wrong if one of the inner checksums is
> @@ -965,7 +975,8 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>   		if (info.is_tunnel == 1) {
>   			tx_ol_flags |= process_outer_cksums(outer_l3_hdr, &info,
>   					tx_offloads,
> -					!!(tx_ol_flags & RTE_MBUF_F_TX_TCP_SEG));
> +					!!(tx_ol_flags & RTE_MBUF_F_TX_TCP_SEG),
> +					m);
>   		}
>   
>   		/* step 3: fill the mbuf meta data (flags and header lengths) */