461 lines
11 KiB
C
461 lines
11 KiB
C
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#ifndef _ISCSI_H
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#define _ISCSI_H
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/** @file
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*
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* iSCSI protocol
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*
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*/
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#include <stdint.h>
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#include <gpxe/tcp.h>
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#include <gpxe/scsi.h>
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/**
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* iSCSI segment lengths
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*
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* iSCSI uses an icky structure with one one-byte field (a dword
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* count) and one three-byte field (a byte count). This structure,
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* and the accompanying macros, relieve some of the pain.
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*/
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union iscsi_segment_lengths {
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struct {
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/** The AHS length (measured in dwords) */
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uint8_t ahs_len;
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/** The data length (measured in bytes), in network
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* byte order
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*/
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uint8_t data_len[3];
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} bytes;
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/** Ths data length (measured in bytes), in network byte
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* order, with ahs_len as the first byte.
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*/
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uint32_t ahs_and_data_len;
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};
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/** The length of the additional header segment, in dwords */
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#define ISCSI_AHS_LEN( segment_lengths ) \
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( (segment_lengths).bytes.ahs_len )
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/** The length of the data segment, in bytes, excluding any padding */
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#define ISCSI_DATA_LEN( segment_lengths ) \
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( ntohl ( (segment_lengths).ahs_and_data_len ) & 0xffffff )
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/** The padding of the data segment, in bytes */
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#define ISCSI_DATA_PAD_LEN( segment_lengths ) \
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( ( 0 - (segment_lengths).bytes.data_len[2] ) & 0x03 )
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/** Set additional header and data segment lengths */
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#define ISCSI_SET_LENGTHS( segment_lengths, ahs_len, data_len ) do { \
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(segment_lengths).ahs_and_data_len = \
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htonl ( data_len | ( ahs_len << 24 ) ); \
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} while ( 0 )
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/**
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* iSCSI basic header segment common fields
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*
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*/
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struct iscsi_bhs_common {
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/** Opcode */
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uint8_t opcode;
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/** Flags */
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uint8_t flags;
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/** Fields specific to the PDU type */
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uint8_t other_a[2];
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/** Segment lengths */
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union iscsi_segment_lengths lengths;
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/** Fields specific to the PDU type */
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uint8_t other_b[8];
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/** Initiator Task Tag */
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uint32_t itt;
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/** Fields specific to the PDU type */
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uint8_t other_c[28];
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};
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/** Opcode mask */
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#define ISCSI_OPCODE_MASK 0x3f
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/** Immediate delivery */
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#define ISCSI_FLAG_IMMEDIATE 0x40
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/** Final PDU of a sequence */
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#define ISCSI_FLAG_FINAL 0x80
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/**
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* iSCSI login request basic header segment
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*
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*/
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struct iscsi_bhs_login_request {
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/** Opcode */
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uint8_t opcode;
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/** Flags */
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uint8_t flags;
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/** Maximum supported version number */
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uint8_t version_max;
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/** Minimum supported version number */
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uint8_t version_min;
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/** Segment lengths */
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union iscsi_segment_lengths lengths;
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/** Initiator session ID (IANA format) enterprise number and flags */
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uint32_t isid_iana_en;
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/** Initiator session ID (IANA format) qualifier */
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uint16_t isid_iana_qual;
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/** Target session identifying handle */
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uint16_t tsih;
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/** Initiator Task Tag */
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uint32_t itt;
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/** Connection ID */
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uint16_t cid;
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/** Reserved */
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uint16_t reserved_a;
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/** Command sequence number */
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uint32_t cmdsn;
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/** Expected status sequence number */
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uint32_t expstatsn;
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/** Reserved */
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uint8_t reserved_b[16];
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};
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/** Login request opcode */
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#define ISCSI_OPCODE_LOGIN_REQUEST 0x03
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/** Willingness to transition to next stage */
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#define ISCSI_LOGIN_FLAG_TRANSITION 0x80
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/** Key=value pairs continued in subsequent request */
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#define ISCSI_LOGIN_FLAG_CONTINUE 0x40
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/* Current stage values and mask */
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#define ISCSI_LOGIN_CSG_MASK 0x0c
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#define ISCSI_LOGIN_CSG_SECURITY_NEGOTIATION 0x00
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#define ISCSI_LOGIN_CSG_OPERATIONAL_NEGOTIATION 0x04
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#define ISCSI_LOGIN_CSG_FULL_FEATURE_PHASE 0x0c
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/* Next stage values and mask */
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#define ISCSI_LOGIN_NSG_MASK 0x03
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#define ISCSI_LOGIN_NSG_SECURITY_NEGOTIATION 0x00
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#define ISCSI_LOGIN_NSG_OPERATIONAL_NEGOTIATION 0x01
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#define ISCSI_LOGIN_NSG_FULL_FEATURE_PHASE 0x03
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/** ISID IANA format marker */
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#define ISCSI_ISID_IANA 0x40000000
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/** Fen Systems Ltd. IANA enterprise number
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*
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* Permission is hereby granted to use Fen Systems Ltd.'s IANA
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* enterprise number with this iSCSI implementation.
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*/
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#define IANA_EN_FEN_SYSTEMS 10019
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/**
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* iSCSI login response basic header segment
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*
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*/
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struct iscsi_bhs_login_response {
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/** Opcode */
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uint8_t opcode;
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/** Flags */
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uint8_t flags;
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/** Maximum supported version number */
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uint8_t version_max;
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/** Minimum supported version number */
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uint8_t version_min;
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/** Segment lengths */
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union iscsi_segment_lengths lengths;
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/** Initiator session ID (IANA format) enterprise number and flags */
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uint32_t isid_iana_en;
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/** Initiator session ID (IANA format) qualifier */
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uint16_t isid_iana_qual;
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/** Target session identifying handle */
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uint16_t tsih;
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/** Initiator Task Tag */
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uint32_t itt;
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/** Reserved */
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uint32_t reserved_a;
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/** Status sequence number */
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uint32_t statsn;
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/** Expected command sequence number */
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uint32_t expcmdsn;
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/** Maximum command sequence number */
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uint32_t maxcmdsn;
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/** Status class */
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uint8_t status_class;
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/** Status detail */
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uint8_t status_detail;
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/** Reserved */
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uint8_t reserved_b[10];
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};
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/** Login response opcode */
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#define ISCSI_OPCODE_LOGIN_RESPONSE 0x23
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/**
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* iSCSI SCSI command basic header segment
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*
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*/
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struct iscsi_bhs_scsi_command {
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/** Opcode */
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uint8_t opcode;
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/** Flags */
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uint8_t flags;
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/** Reserved */
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uint16_t reserved_a;
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/** Segment lengths */
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union iscsi_segment_lengths lengths;
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/** SCSI Logical Unit Number */
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uint8_t lun[8];
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/** Initiator Task Tag */
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uint32_t itt;
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/** Expected data transfer length */
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uint32_t exp_len;
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/** Command sequence number */
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uint32_t cmdsn;
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/** Expected status sequence number */
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uint32_t expstatsn;
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/** SCSI Command Descriptor Block (CDB) */
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union scsi_cdb cdb;
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};
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/** SCSI command opcode */
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#define ISCSI_OPCODE_SCSI_COMMAND 0x01
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/** Command will read data */
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#define ISCSI_COMMAND_FLAG_READ 0x40
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/** Command will write data */
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#define ISCSI_COMMAND_FLAG_WRITE 0x20
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/* Task attributes */
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#define ISCSI_COMMAND_ATTR_UNTAGGED 0x00
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#define ISCSI_COMMAND_ATTR_SIMPLE 0x01
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#define ISCSI_COMMAND_ATTR_ORDERED 0x02
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#define ISCSI_COMMAND_ATTR_HEAD_OF_QUEUE 0x03
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#define ISCSI_COMMAND_ATTR_ACA 0x04
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/**
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* iSCSI SCSI response basic header segment
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*
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*/
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struct iscsi_bhs_scsi_response {
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/** Opcode */
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uint8_t opcode;
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/** Flags */
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uint8_t flags;
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/** Response code */
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uint8_t response;
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/** SCSI status code */
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uint8_t status;
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/** Segment lengths */
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union iscsi_segment_lengths lengths;
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/** Reserved */
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uint8_t reserved_a[8];
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/** Initiator Task Tag */
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uint32_t itt;
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/** SNACK tag */
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uint32_t snack;
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/** Status sequence number */
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uint32_t statsn;
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/** Expected command sequence number */
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uint32_t expcmdsn;
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/** Maximum command sequence number */
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uint32_t maxcmdsn;
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/** Expected data sequence number */
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uint32_t expdatasn;
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/** Reserved */
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uint8_t reserved_b[8];
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};
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/** SCSI response opcode */
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#define ISCSI_OPCODE_SCSI_RESPONSE 0x21
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/** SCSI command completed at target */
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#define ISCSI_RESPONSE_COMMAND_COMPLETE 0x00
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/** SCSI target failure */
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#define ISCSI_RESPONSE_TARGET_FAILURE 0x01
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/**
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* iSCSI data in basic header segment
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*
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*/
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struct iscsi_bhs_data_in {
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/** Opcode */
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uint8_t opcode;
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/** Flags */
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uint8_t flags;
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/** Reserved */
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uint8_t reserved_a;
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/** SCSI status code */
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uint8_t status;
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/** Segment lengths */
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union iscsi_segment_lengths lengths;
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/** Logical Unit Number */
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uint8_t lun[8];
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/** Initiator Task Tag */
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uint32_t itt;
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/** Target Transfer Tag */
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uint32_t ttt;
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/** Status sequence number */
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uint32_t statsn;
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/** Expected command sequence number */
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uint32_t expcmdsn;
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/** Maximum command sequence number */
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uint32_t maxcmdsn;
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/** Data sequence number */
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uint32_t datasn;
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/** Buffer offset */
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uint32_t offset;
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/** Residual count */
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uint32_t residual_count;
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};
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/** Data in opcode */
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#define ISCSI_OPCODE_DATA_IN 0x25
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/** Data requires acknowledgement */
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#define ISCSI_DATA_FLAG_ACKNOWLEDGE 0x40
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/** Data overflow occurred */
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#define ISCSI_DATA_FLAG_OVERFLOW 0x04
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/** Data underflow occurred */
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#define ISCSI_DATA_FLAG_UNDERFLOW 0x02
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/** SCSI status code and verflow/underflow flags are valid */
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#define ISCSI_DATA_FLAG_STATUS 0x01
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/**
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* An iSCSI basic header segment
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*/
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union iscsi_bhs {
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struct iscsi_bhs_common common;
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struct iscsi_bhs_login_request login_request;
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struct iscsi_bhs_login_response login_response;
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struct iscsi_bhs_scsi_command scsi_command;
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struct iscsi_bhs_scsi_response scsi_response;
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struct iscsi_bhs_data_in data_in;
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unsigned char bytes[ sizeof ( struct iscsi_bhs_common ) ];
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};
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/** State */
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enum iscsi_state {
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/** In the process of logging in */
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ISCSI_STATE_FAILED = -1,
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ISCSI_STATE_NOT_CONNECTED = 0,
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ISCSI_STATE_IDLE,
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ISCSI_STATE_LOGGING_IN,
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ISCSI_STATE_READING_DATA,
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};
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/** State of an iSCSI TX engine */
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enum iscsi_tx_state {
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/** Nothing to send */
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ISCSI_TX_IDLE = 0,
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/** Sending the basic header segment */
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ISCSI_TX_BHS,
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/** Sending the additional header segment */
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ISCSI_TX_AHS,
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/** Sending the data segment */
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ISCSI_TX_DATA,
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/** Sending the data segment padding */
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ISCSI_TX_DATA_PADDING,
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};
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/** State of an iSCSI RX engine */
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enum iscsi_rx_state {
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/** Receiving the basic header segment */
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ISCSI_RX_BHS = 0,
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/** Receiving the additional header segment */
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ISCSI_RX_AHS,
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/** Receiving the data segment */
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ISCSI_RX_DATA,
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/** Receiving the data segment padding */
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ISCSI_RX_DATA_PADDING,
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};
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/** An iSCSI session */
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struct iscsi_session {
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/** TCP connection for this session */
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struct tcp_connection tcp;
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/** Initiator IQN */
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const char *initiator;
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/** Target IQN */
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const char *target;
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/** Block size in bytes */
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size_t block_size;
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/** Starting block number of the current data transfer */
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unsigned long block_start;
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/** Block count of the current data transfer */
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unsigned long block_count;
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/** Block read callback function
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*
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* Note that this may be called several times, since it is
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* called per-packet rather than per-block.
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*/
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void ( * block_read_callback ) ( void *private, const void *data,
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unsigned long offset, size_t len );
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/** Block read callback private data
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*
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* This is passed to block_read_callback()
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*/
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void *block_read_private;
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/** State of the session */
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enum iscsi_state state;
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/** Target session identifying handle
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*
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* This is assigned by the target when we first log in, and
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* must be reused on subsequent login attempts.
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*/
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uint16_t tsih;
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/** Initiator task tag
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*
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* This is the tag of the current command. It is incremented
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* whenever a final response PDU is received.
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*/
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uint32_t itt;
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/** Command sequence number
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*
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* This is the sequence number of the current command, used to
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* fill out the CmdSN field in iSCSI request PDUs. It is
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* updated with the value of the ExpCmdSN field whenever we
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* receive an iSCSI response PDU containing such a field.
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*/
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uint32_t cmdsn;
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/** Status sequence number
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*
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* This is the most recent status sequence number present in
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* the StatSN field of an iSCSI response PDU containing such a
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* field. Whenever we send an iSCSI request PDU, we fill out
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* the ExpStatSN field with this value plus one.
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*/
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uint32_t statsn;
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/** Basic header segment for current TX PDU */
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union iscsi_bhs tx_bhs;
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/** State of the TX engine */
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enum iscsi_tx_state tx_state;
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/** Byte offset within the current TX state */
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size_t tx_offset;
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/** Basic header segment for current RX PDU */
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union iscsi_bhs rx_bhs;
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/** State of the RX engine */
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enum iscsi_rx_state rx_state;
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/** Byte offset within the current RX state */
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size_t rx_offset;
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};
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||
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static inline int iscsi_busy ( struct iscsi_session *iscsi ) {
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||
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return ( iscsi->state > ISCSI_STATE_IDLE );
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||
|
}
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||
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||
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static inline int iscsi_error ( struct iscsi_session *iscsi ) {
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||
|
return ( iscsi->state == ISCSI_STATE_FAILED );
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||
|
}
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||
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||
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#endif /* _ISCSI_H */
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