net/mlx5: zero out UDP checksum in encapsulation

Mellanox NICs do not support UDP checksum hardware tx offload over IPv6.
This limitation becomes critical for UDP based tunnels like VXLAN.
Beside the UDP checksum validity is required by IPv6 there is an option
in Linux to allow accepting UDP zero sum (see udp6zerocsumrx in iproute2
package).

This patch zeroes out the UDP checksum field for encapsulation headers
in raw encap action.

Signed-off-by: Eli Britstein <elibr@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>

diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
index 8f64182..7a8f16b 100644 (file)
--- a/drivers/net/mlx5/mlx5_flow_dv.c
+++ b/drivers/net/mlx5/mlx5_flow_dv.c
@@ -1454,6 +1454,50 @@ flow_dv_convert_encap_data(const struct rte_flow_item *items, uint8_t *buf,
        return 0;
 }
 
+static int
+flow_dv_zero_encap_udp_csum(void *data, struct rte_flow_error *error)
+{
+       struct rte_ether_hdr *eth = NULL;
+       struct rte_vlan_hdr *vlan = NULL;
+       struct rte_ipv6_hdr *ipv6 = NULL;
+       struct rte_udp_hdr *udp = NULL;
+       char *next_hdr;
+       uint16_t proto;
+
+       eth = (struct rte_ether_hdr *)data;
+       next_hdr = (char *)(eth + 1);
+       proto = RTE_BE16(eth->ether_type);
+
+       /* VLAN skipping */
+       while (proto == RTE_ETHER_TYPE_VLAN || proto == RTE_ETHER_TYPE_QINQ) {
+               next_hdr += sizeof(struct rte_vlan_hdr);
+               vlan = (struct rte_vlan_hdr *)next_hdr;
+               proto = RTE_BE16(vlan->eth_proto);
+       }
+
+       /* HW calculates IPv4 csum. no need to proceed */
+       if (proto == RTE_ETHER_TYPE_IPV4)
+               return 0;
+
+       /* non IPv4/IPv6 header. not supported */
+       if (proto != RTE_ETHER_TYPE_IPV6) {
+               return rte_flow_error_set(error, ENOTSUP,
+                                         RTE_FLOW_ERROR_TYPE_ACTION,
+                                         NULL, "Cannot offload non IPv4/IPv6");
+       }
+
+       ipv6 = (struct rte_ipv6_hdr *)next_hdr;
+
+       /* ignore non UDP */
+       if (ipv6->proto != IPPROTO_UDP)
+               return 0;
+
+       udp = (struct rte_udp_hdr *)(ipv6 + 1);
+       udp->dgram_cksum = 0;
+
+       return 0;
+}
+
 /**
  * Convert L2 encap action to DV specification.
  *
@@ -1492,6 +1536,8 @@ flow_dv_create_action_l2_encap(struct rte_eth_dev *dev,
                        (const struct rte_flow_action_raw_encap *)action->conf;
                res.size = raw_encap_data->size;
                memcpy(res.buf, raw_encap_data->data, res.size);
+               if (flow_dv_zero_encap_udp_csum(res.buf, error))
+                       return -rte_errno;
        } else {
                if (action->type == RTE_FLOW_ACTION_TYPE_VXLAN_ENCAP)
                        encap_data =