On 11/2/23 23:58, Stanislav Fomichev wrote:
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h index 2ecf79282c26..b0ee7ad19b51 100644 --- a/include/uapi/linux/if_xdp.h +++ b/include/uapi/linux/if_xdp.h @@ -106,6 +106,41 @@ struct xdp_options { #define XSK_UNALIGNED_BUF_ADDR_MASK \ ((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)+/* Request transmit timestamp. Upon completion, put it into tx_timestamp+ * field of struct xsk_tx_metadata. + */ +#define XDP_TXMD_FLAGS_TIMESTAMP (1 << 0) + +/* Request transmit checksum offload. Checksum start position and offset + * are communicated via csum_start and csum_offset fields of struct + * xsk_tx_metadata. + */ +#define XDP_TXMD_FLAGS_CHECKSUM (1 << 1) + +/* AF_XDP offloads request. 'request' union member is consumed by the driver + * when the packet is being transmitted. 'completion' union member is + * filled by the driver when the transmit completion arrives. + */ +struct xsk_tx_metadata { + union { + struct { + __u32 flags; + + /* XDP_TXMD_FLAGS_CHECKSUM */ + + /* Offset from desc->addr where checksumming should start. */ + __u16 csum_start; + /* Offset from csum_start where checksum should be stored. */ + __u16 csum_offset; + } request; + + struct { + /* XDP_TXMD_FLAGS_TIMESTAMP */ + __u64 tx_timestamp; + } completion; + }; +};
This looks wrong to me. It looks like member @flags is not avail at completion time. At completion time, I assume we also want to know if someone requested to get the timestamp for this packet (else we could read garbage). Another thing (I've raised this before): It would be really practical to store an u64 opaque value at TX and then read it at Completion time. One use-case is a forwarding application storing HW RX-time and comparing this to TX completion time to deduce the time spend processing the packet. --Jesper
