Module intel_ethernet::descriptors

The different descriptor types used by Intel NICs. Usually the newer NICs use more advanced descriptor types but retain support for older ones. The difference in the types is the amount of packet information that is included in the descriptor, and the format.

Structs

• AdvancedRxDescriptor
  Advanced Receive Descriptor used in the Ixgbe driver. It has 2 modes: Read and Write Back, both of which use the whole 128 bits. There is one receive descriptor per receive buffer that can be converted between these 2 modes. Read contains the addresses that the driver writes. Write Back contains information the hardware writes on receiving a packet. More information can be found in the 82599 datasheet.
• AdvancedTxDescriptor
  Advanced Transmit Descriptor used by the ixgbe NIC driver.
• LegacyRxDescriptor
  This struct is a Legacy Receive Descriptor. The driver writes to the upper 64 bits, and the NIC writes to the lower 64 bits. It’s the descriptor type used in older Intel NICs and the E1000 driver.
• LegacyTxDescriptor
  This struct is a Legacy Transmit Descriptor. It’s the descriptor type used in older Intel NICs and the E1000 driver.

Constants

• RX_STATUS_DD
  Rx Status: Descriptor Done
• RX_STATUS_EOP
  Rx Status: End of Packet
• TX_CMD_DEXT
  Tx Command: Descriptor Extension (Advanced format)
• TX_CMD_EOP
  Tx Command: End of Packet
• TX_CMD_IC
  Tx Command: Insert Checksum
• TX_CMD_IDE
  Tx Command: Interrupt Delay Enable
• TX_CMD_IFCS
  Tx Command: Insert MAC FCS
• TX_CMD_RPS
  Tx Command: Report Packet Sent
• TX_CMD_RS
  Tx Command: Report Status
• TX_CMD_VLE
  Tx Command: VLAN Packet Enable
• TX_DTYP_ADV
  Tx Descriptor Type: advanced
• TX_PAYLEN_SHIFT
  Tx Descriptor paylen shift The paylen is located at bit 46 in the upper 64 bits of the advanced Tx descriptor. Since we have divided the upper 64 bits into 4 parts (u16,u8,u8,u32), the paylen is then located at bit 14 of the upper 32 bits of the descriptor.
• TX_STATUS_DD
  Tx Status: descriptor Done

Traits

• RxDescriptor
  A trait for the minimum set of functions needed to receive a packet using one of Intel’s receive descriptor types. Receive descriptors contain the physical address where an incoming packet should be stored by the NIC, as well as bits that are updated by the HW once the packet is received. There is one receive descriptor per receive buffer. Receive functions defined in the Network_Interface_Card crate expect a receive descriptor to implement this trait.
• TxDescriptor
  A trait for the minimum set of functions needed to transmit a packet using one of Intel’s transmit descriptor types. Transmit descriptors contain the physical address where an outgoing packet is stored, as well as bits that are updated by the HW once the packet is sent. There is one transmit descriptor per transmit buffer. Transmit functions defined in the Network_Interface_Card crate expect a transmit descriptor to implement this trait.