drivers/scsi/iscsi_tcp.h

   1 /*
   2  * iSCSI Initiator TCP Transport
   3  * Copyright (C) 2004 Dmitry Yusupov
   4  * Copyright (C) 2004 Alex Aizman
   5  * Copyright (C) 2005 - 2006 Mike Christie
   6  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
   7  * maintained by open-iscsi@googlegroups.com
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published
  11  * by the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17  * General Public License for more details.
  18  *
  19  * See the file COPYING included with this distribution for more details.
  20  */
  21
  22 #ifndef ISCSI_TCP_H
  23 #define ISCSI_TCP_H
  24
  25 #include <scsi/libiscsi.h>
  26
  27 struct crypto_hash;
  28 struct socket;
  29 struct iscsi_tcp_conn;
  30 struct iscsi_segment;
  31
  32 typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
  33                                     struct iscsi_segment *);
  34
  35 struct iscsi_segment {
  36         unsigned char           *data;
  37         unsigned int            size;
  38         unsigned int            copied;
  39         unsigned int            total_size;
  40         unsigned int            total_copied;
  41
  42         struct hash_desc        *hash;
  43         unsigned char           recv_digest[ISCSI_DIGEST_SIZE];
  44         unsigned char           digest[ISCSI_DIGEST_SIZE];
  45         unsigned int            digest_len;
  46
  47         struct scatterlist      *sg;
  48         void                    *sg_mapped;
  49         unsigned int            sg_offset;
  50
  51         iscsi_segment_done_fn_t *done;
  52 };
  53
  54 /* Socket connection recieve helper */
  55 struct iscsi_tcp_recv {
  56         struct iscsi_hdr        *hdr;
  57         struct iscsi_segment    segment;
  58
  59         /* Allocate buffer for BHS + AHS */
  60         uint32_t                hdr_buf[64];
  61
  62         /* copied and flipped values */
  63         int                     datalen;
  64 };
  65
  66 /* Socket connection send helper */
  67 struct iscsi_tcp_send {
  68         struct iscsi_hdr        *hdr;
  69         struct iscsi_segment    segment;
  70         struct iscsi_segment    data_segment;
  71 };
  72
  73 struct iscsi_tcp_conn {
  74         struct iscsi_conn       *iscsi_conn;
  75         struct socket           *sock;
  76         int                     stop_stage;     /* conn_stop() flag: *
  77                                                  * stop to recover,  *
  78                                                  * stop to terminate */
  79         /* control data */
  80         struct iscsi_tcp_recv   in;             /* TCP receive context */
  81         struct iscsi_tcp_send   out;            /* TCP send context */
  82
  83         /* old values for socket callbacks */
  84         void                    (*old_data_ready)(struct sock *, int);
  85         void                    (*old_state_change)(struct sock *);
  86         void                    (*old_write_space)(struct sock *);
  87
  88         /* data and header digests */
  89         struct hash_desc        tx_hash;        /* CRC32C (Tx) */
  90         struct hash_desc        rx_hash;        /* CRC32C (Rx) */
  91
  92         /* MIB custom statistics */
  93         uint32_t                sendpage_failures_cnt;
  94         uint32_t                discontiguous_hdr_cnt;
  95
  96         int                     error;
  97
  98         ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
  99 };
 100
 101 struct iscsi_data_task {
 102         struct iscsi_data       hdr;                    /* PDU */
 103         char                    hdrext[ISCSI_DIGEST_SIZE];/* Header-Digest */
 104 };
 105
 106 struct iscsi_r2t_info {
 107         __be32                  ttt;            /* copied from R2T */
 108         __be32                  exp_statsn;     /* copied from R2T */
 109         uint32_t                data_length;    /* copied from R2T */
 110         uint32_t                data_offset;    /* copied from R2T */
 111         int                     sent;           /* R2T sequence progress */
 112         int                     data_count;     /* DATA-Out payload progress */
 113         int                     solicit_datasn;
 114         struct iscsi_data_task  dtask;          /* Data-Out header buf */
 115 };
 116
 117 struct iscsi_tcp_task {
 118         struct iscsi_hdr_buff {
 119                 struct iscsi_cmd        cmd_hdr;
 120                 char                    hdrextbuf[ISCSI_MAX_AHS_SIZE +
 121                                                   ISCSI_DIGEST_SIZE];
 122         } hdr;
 123
 124         int                     sent;
 125         uint32_t                exp_datasn;     /* expected target's R2TSN/DataSN */
 126         int                     data_offset;
 127         struct iscsi_r2t_info   *r2t;           /* in progress R2T    */
 128         struct iscsi_pool       r2tpool;
 129         struct kfifo            *r2tqueue;
 130         struct iscsi_data_task  unsol_dtask;    /* Data-Out header buf */
 131 };
 132
 133 #endif /* ISCSI_H */