Re: [dpdk-dev] [PATCH 3/3] testpmd:rework csum forward engine

[Olivier MATZ <olivier.matz@6wind.com>]

Hi Jijiang,

On 11/27/2014 09:18 AM, Jijiang Liu wrote:
> The changes include:
> 1. use the new introduced ol_flags and fields in csumonly.c file;
> 2. fix an issue of outer UDP checksum check;
> 3. fix an issue that is if the TESTPMD_TX_OFFLOAD_IP_CKSUM is not set, and the "ol_flags |= PKT_TX_IPV4" should be done in the process_inner_cksums();
>
> Signed-off-by: Jijiang Liu <jijiang.liu@intel.com>
> ---
>   app/test-pmd/csumonly.c |   55 +++++++++++++++++++++++++---------------------
>   1 files changed, 30 insertions(+), 25 deletions(-)
>
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
> index d8c080a..0727510 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -189,11 +189,12 @@ process_inner_cksums(void *l3_hdr, uint16_t ethertype, uint16_t l3_len,
>   		} else {
>   			if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_IP_CKSUM)
>   				ol_flags |= PKT_TX_IP_CKSUM;
> -			else
> +			else {
>   				ipv4_hdr->hdr_checksum =
>   					rte_ipv4_cksum(ipv4_hdr);
> +				ol_flags |= PKT_TX_IPV4;
> +			}
>   		}
> -		ol_flags |= PKT_TX_IPV4;

Same remark than in the cover letter. I think we currently don't agree
on the meaning of PKT_TX_IPV4 and PKT_TX_IPV6.


>   	udp_hdr = (struct udp_hdr *)((char *)outer_l3_hdr + outer_l3_len);
>   	/* do not recalculate udp cksum if it was 0 */
>   	if (udp_hdr->dgram_cksum != 0) {
>   		udp_hdr->dgram_cksum = 0;
> -		if ((testpmd_ol_flags & TESTPMD_TX_OFFLOAD_VXLAN_CKSUM) == 0) {
> -			if (outer_ethertype == _htons(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);
> -		}
> +		if (outer_ethertype == _htons(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);

So, I understand that today no dpdk driver support the offload of
outer udp checksum, and that it has to be done in software?


> @@ -383,10 +385,6 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>   			if (((m->ol_flags & PKT_RX_TUNNEL_IPV4_HDR) ||
>   					(m->ol_flags & PKT_RX_TUNNEL_IPV6_HDR)))
>   				tunnel = 1;
> -			/* else check udp destination port, 4789 is the default
> -			 * vxlan port (rfc7348) */
> -			else if (udp_hdr->dst_port == _htons(4789))
> -				tunnel = 1;
>
>   			if (tunnel == 1) {
>   				outer_ethertype = ethertype;
> @@ -394,6 +392,11 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>   				outer_l3_len = l3_len;
>   				outer_l3_hdr = l3_hdr;
>
> +				/* check udp destination port, 4789 is the default
> +				 * vxlan port (rfc7348) */
> +				if (udp_hdr->dst_port == _htons(4789))
> +					l4_tun_len = ETHER_VXLAN_HLEN;
> +

Why moving this? It won't work anymore with drivers != i40e.


>   				eth_hdr = (struct ether_hdr *)((char *)udp_hdr +
>   					sizeof(struct udp_hdr) +
>   					sizeof(struct vxlan_hdr));
> @@ -432,10 +435,11 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>
>   		if (tunnel == 1) {
>   			if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_VXLAN_CKSUM) {
> -				m->l2_len = outer_l2_len;
> -				m->l3_len = outer_l3_len;
> -				m->inner_l2_len = l2_len;
> -				m->inner_l3_len = l3_len;
> +				m->outer_l2_len = outer_l2_len;
> +				m->outer_l3_len = outer_l3_len;
> +				m->l2_len = l2_len;
> +				m->l3_len = l3_len;
> +				m->l4_tun_len = l4_tun_len;
>   			}
>   			else {
>   				/* if we don't do vxlan cksum in hw,
> @@ -470,7 +474,7 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>   				{ PKT_TX_UDP_CKSUM, PKT_TX_L4_MASK },
>   				{ PKT_TX_TCP_CKSUM, PKT_TX_L4_MASK },
>   				{ PKT_TX_SCTP_CKSUM, PKT_TX_L4_MASK },
> -				{ PKT_TX_VXLAN_CKSUM, PKT_TX_VXLAN_CKSUM },
> +				{ PKT_TX_UDP_TUNNEL_PKT, PKT_TX_UDP_TUNNEL_PKT },
>   				{ PKT_TX_TCP_SEG, PKT_TX_TCP_SEG },
>   			};
>   			unsigned j;
> @@ -498,8 +502,9 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>   					m->l2_len, m->l3_len, m->l4_len);
>   			if ((tunnel == 1) &&
>   				(testpmd_ol_flags & TESTPMD_TX_OFFLOAD_VXLAN_CKSUM))
> -				printf("tx: m->inner_l2_len=%d m->inner_l3_len=%d\n",
> -					m->inner_l2_len, m->inner_l3_len);
> +				printf("tx: m->outer_l2_len=%d m->outer_l3_len=%d\n"
> +					"m->l4_tun_len=%d", m->outer_l2_len,
> +					m->outer_l3_len, m->l4_tun_len);
>   			if (tso_segsz != 0)
>   				printf("tx: m->tso_segsz=%d\n", m->tso_segsz);
>   			printf("tx: flags=");
>

One more comment:

I think the help of csum forward engine in testpmd command lines +
all the comments in csumonly.c should be checked. For example, I
can see: " The VxLAN flag concerns the outer IP and UDP layer (if
packet is recognized as a vxlan packet)". If it concerns the IP header
only, the comment should be modified.

Regards,
Olivier