166 lines
6.8 KiB
Groff
166 lines
6.8 KiB
Groff
.\" $FreeBSD$
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.Dd January 27, 2017
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.Dt IFlIBTXTX(9)
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.Os
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.Sh NAME
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.Nm iflibtxrx
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.Nd Device Dependent Transmit and Receive Functions
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.Sh SYNOPSIS
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.In "ifdi_if.h"
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.Ss "Interface Manipulation Functions"
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.Ft int
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.Fn isc_txd_encap "void *sc, if_pkt_into_t pi"
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.Ft void
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.Fn isc_txd_flush "void *sc, uint16_t qid, uint32_t _pidx_or_credits_"
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.Ft int *
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.Fn isc_txd_credits_update "void *sc, uint16_t qid, uint32_t credits"
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.Ft int *
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.Fn isc_rxd_available "void *sc, uint16_t qsid, uint32_t cidx"
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.Ft void *
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.Fn isc_rxd_refill "void *sc, uint16_t qsid, uint8_t flid, uint32_t pidx, uint64_t *paddrs, caddr_t *vaddrs, uint16_t count"
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.Ft void *
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.Fn isc_rxd_flush "void *sc, uint16_t qsid, uint8_t flid, uint32_t pidx"
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.Ft int
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.Fn isc_rxd_pkt_get "void *sc, if_rxd_info_t ri"
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.Ss "Global Variables"
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.Vt extern struct if_txrx
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.Sh DATA STRUCTURES
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The device dependent mechanisms for handling packet transmit and receive are primarily defined by the functions named above. The if_pkt_info data structure contains statistics and identifying info necessary for packet transmission. While the data structure for packet receipt is the if_rxd_info structure.
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.Pp
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.Ss The if_pkt_info Structure
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The fields of
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.Vt "struct if_pkt_info"
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are as follows:
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.Bl -tag -width ".Va if_capabilities" -offset indent
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.It Va ipi_len
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.Pq Vt "uint32_t"
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Denotes the size of packet to be sent on the transmit queue.
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.It Va ipi_segs
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.Pq Vt "bus_dma_segment_t *"
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A pointer to the bus_dma_segment of the device independent transfer queue defined in iflib.
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.It Va ipi_qsidx
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Unique index value assigned sequentially to each transmit queue. Used to reference the currently transmitting queue.
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.It Va ipi_nsegs
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.Pq Vt "uint16_t"
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Number of descriptors to be read into the device dependent transfer descriptors.
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.It Va ipi_ndescs
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.Pq Vt "uint16_t"
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Number of descriptors in use. Calculated by subtracting the old pidx value from the new pidx value.
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.It Va ipi_flags
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.Pq Vt "uint16_t"
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Flags defined on a per packet basis.
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.It Va ipi_pidx
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.Pq Vt "uint32_t"
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Value of first pidx sent to the isc_encap function for encapsulation and subsequent transmission.
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.It Va ipi_new_pidx
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.Pq Vt "uint32_t"
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Value set after the termination of the isc_encap function. This value will become the first pidx sent to the isc-encap the next time that the function is called.
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.It Va \fBThe Following Fields Are Used For Offload Handling\fP
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.It Va ipi_csum_flags
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.Pq Vt "uint64_t"
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Flags describing the checksum values. Used on a per packet basis.
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.It Va ipi_tso_segsz
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.Pq Vt "uint16_t"
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Size of the TSO Segment Size.
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.It Va ipi_mflags
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.Pq Vt "uint16_t"
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Flags describing the operational parameters of the mbuf.
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.It Va ipi_vtag
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.Pq Vt "uint16_t"
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Contains the VLAN information in the Ethernet Frame.
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.It Va ipi_etype
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.Pq Vt "uint16_t"
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Type of ethernet header protocol as contained by the struct ether_vlan_header.
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.It Va ipi_ehrdlen
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.Pq Vt "uint8_t"
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Length of the Ethernet Header.
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.It Va ipi_ip_hlen
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.Pq Vt "uint8_t"
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Length of the TCP Header
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.It Va ipi_tcp_hlen
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.Pq Vt "uint8_t"
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Length of the TCP Header.
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.It Va ipi_tcp_hflags
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.Pq Vt "uint8_t"
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Flags describing the operational parameters of the TCP Header.
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.It Va ipi_ipproto
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.Pq Vt "uint8_t"
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Specifies the type of IP Protocol in use. Example TCP, UDP, or SCTP.
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.El
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.Ss The if_rxd_info Structure
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The fields of
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.Vt "struct if_rxd_info"
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are as follows:
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.Bl -tag -width ".Va if_capabilities" -offset indent
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.It Va iri_qsidx
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.Pq Vt "uint16_t"
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Unique index value assigned sequentially to each receive queue. Used to reference the currently receiving queue.
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.It Va iri_vtag
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.Pq Vt "uint16_t"
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Contains the VLAN information in the Ethernet Frame.
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.It Va iri_len
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.Pq Vt "uint16_t"
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Denotes the size of a received packet.
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.It Va iri_next_offset
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.Pq Vt "uint16_t"
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Denotes the offset value for the next packet to be receive. A Null value signifies the end of packet.
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.It Va iri_cidx
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.Pq Vt "uint32_t"
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Denotes the index value of the packet currently being processed in the consumer queue.
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.It Va iri_flowid
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.Pq Vt "uint32_t"
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Value of the RSS hash for the packet.
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.It Va iri_flags
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.Pq Vt "uint"
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Flags describing the operational parameters of the mbuf contained in the receive packet.
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.It Va iri_csum_flags
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.Pq Vt "uint32_t"
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Flags describing the checksum value contained in the receive packet.
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.It Va iri_csum_data
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.Pq Vt "uint32_t"
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Checksum data contained in the mbuf packet header.
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.It Va iri_m
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.Pq Vt "struct mbuf *"
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A mbuf for drivers that manage their own receive queues.
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.It Va iri_ifp
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.Pq Vt "struct ifnet *"
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A link back to the interface structure. Utilized by drivers that have multiple interface per softc.
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.It Va iri_rsstype
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.Pq Vt "uint8_t"
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The value of the RSS hash type.
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.It Va iri_pad
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.Pq Vt "uint8_t"
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The length of any padding contained by the received data.
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.It Va iri_qidx
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.Pq Vt "uint8_t"
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Represents the type of queue event. If value >= 0 then it is the freelist id otherwise it is a completion queue event.
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.El
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.Sh FUNCTIONS
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All function calls are associated exclusively with either packet transmission or receipt.
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The void *sc passed as the first arguement to all of the following functions repressents the driver's softc.
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.Ss Transmit Packet Functions
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.Bl -ohang -offset indent
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.It Fn isc_txd_encap
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Transmit function that sends a packet on an interface. The if_pkt_info data structure contains data information fields describing the packet. This function returns 0 if successful, otherwise an error value is returned.
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.It Fn isc_txd_flush
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Flush function is called immediately after the isc_txd_encap function transmits a packet. It updates the hardware producer index or increments the descriptors used to pidx_or_credits in the queue designated by the qid number. This is often referred to as poking the doorbell register.
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.It Fn isc_txd_credits_update
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Credit function advances the buffer ring and calculates the credits (descriptors) processed. Until the I/O is complete it cleans the range in case of multisegments and updates the count of processed packets. The function returns the number of processed credits.
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.El
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.Ss Receive Packet Functions
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.Bl -ohang -offset indent
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.It Fn isc_rxd_available
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Function calculates the remaining number of descriptors from a position given by idx. The function returns this value.
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.It Fn isc_rxd_refill
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Starting with the physical address paddrs, the function reads a packet into the rx_ring until a value designated by count is reached. vaddrs is typically not needed and is provided for devices that place their own metadata in the packet header.
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.It Fn isc_rxd_flush
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Flush function updates the producer pointer on the free list flid in queue set number qid to pidx to reflect the presence of new buffers.
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.It Fn isc_rxd_pkt_get
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Process a single software descriptor. rxr->rx_base[i] contains a descriptor that describes a received packet. Hardware specific information about the buffer referred to by ri is returned in the data structure if_rxd_info
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.El
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.Sh "SEE ALSO"
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iflibdd(9), iflibdi(9)
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.Sh AUTHORS
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This manual page was written by
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.An Nicole Graziano
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