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 /* Socket's Receive state machine */
  28 #define IN_PROGRESS_WAIT_HEADER         0x0
  29 #define IN_PROGRESS_HEADER_GATHER       0x1
  30 #define IN_PROGRESS_DATA_RECV           0x2
  31 #define IN_PROGRESS_DDIGEST_RECV        0x3
  32
  33 /* xmit state machine */
  34 #define XMSTATE_IDLE                    0x0
  35 #define XMSTATE_R_HDR                   0x1
  36 #define XMSTATE_W_HDR                   0x2
  37 #define XMSTATE_IMM_HDR                 0x4
  38 #define XMSTATE_IMM_DATA                0x8
  39 #define XMSTATE_UNS_INIT                0x10
  40 #define XMSTATE_UNS_HDR                 0x20
  41 #define XMSTATE_UNS_DATA                0x40
  42 #define XMSTATE_SOL_HDR                 0x80
  43 #define XMSTATE_SOL_DATA                0x100
  44 #define XMSTATE_W_PAD                   0x200
  45 #define XMSTATE_DATA_DIGEST             0x400
  46
  47 #define ISCSI_CONN_RCVBUF_MIN           262144
  48 #define ISCSI_CONN_SNDBUF_MIN           262144
  49 #define ISCSI_PAD_LEN                   4
  50 #define ISCSI_R2T_MAX                   16
  51 #define ISCSI_SG_TABLESIZE              SG_ALL
  52 #define ISCSI_TCP_MAX_CMD_LEN           16
  53
  54 struct socket;
  55
  56 /* Socket connection recieve helper */
  57 struct iscsi_tcp_recv {
  58         struct iscsi_hdr        *hdr;
  59         struct sk_buff          *skb;
  60         int                     offset;
  61         int                     len;
  62         int                     hdr_offset;
  63         int                     copy;
  64         int                     copied;
  65         int                     padding;
  66         struct iscsi_cmd_task   *ctask;         /* current cmd in progress */
  67
  68         /* copied and flipped values */
  69         int                     datalen;
  70         int                     datadgst;
  71         char                    zero_copy_hdr;
  72 };
  73
  74 struct iscsi_tcp_conn {
  75         struct iscsi_conn       *iscsi_conn;
  76         struct socket           *sock;
  77         struct iscsi_hdr        hdr;            /* header placeholder */
  78         char                    hdrext[4*sizeof(__u16) +
  79                                     sizeof(__u32)];
  80         int                     data_copied;
  81         char                    *data;          /* data placeholder */
  82         int                     data_size;      /* actual recv_dlength */
  83         int                     stop_stage;     /* conn_stop() flag: *
  84                                                  * stop to recover,  *
  85                                                  * stop to terminate */
  86         /* iSCSI connection-wide sequencing */
  87         int                     hdr_size;       /* PDU header size */
  88
  89         struct crypto_tfm       *rx_tfm;        /* CRC32C (Rx) */
  90         struct crypto_tfm       *data_rx_tfm;   /* CRC32C (Rx) for data */
  91
  92         /* control data */
  93         struct iscsi_tcp_recv   in;             /* TCP receive context */
  94         int                     in_progress;    /* connection state machine */
  95
  96         /* old values for socket callbacks */
  97         void                    (*old_data_ready)(struct sock *, int);
  98         void                    (*old_state_change)(struct sock *);
  99         void                    (*old_write_space)(struct sock *);
 100
 101         /* xmit */
 102         struct crypto_tfm       *tx_tfm;        /* CRC32C (Tx) */
 103         struct crypto_tfm       *data_tx_tfm;   /* CRC32C (Tx) for data */
 104
 105         /* MIB custom statistics */
 106         uint32_t                sendpage_failures_cnt;
 107         uint32_t                discontiguous_hdr_cnt;
 108
 109         ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
 110 };
 111
 112 struct iscsi_buf {
 113         struct scatterlist      sg;
 114         unsigned int            sent;
 115         char                    use_sendmsg;
 116 };
 117
 118 struct iscsi_data_task {
 119         struct iscsi_data       hdr;                    /* PDU */
 120         char                    hdrext[sizeof(__u32)];  /* Header-Digest */
 121         struct list_head        item;                   /* data queue item */
 122         struct iscsi_buf        digestbuf;              /* digest buffer */
 123         uint32_t                digest;                 /* data digest */
 124 };
 125 #define ISCSI_DTASK_DEFAULT_MAX ISCSI_SG_TABLESIZE * PAGE_SIZE / 512
 126
 127 struct iscsi_tcp_mgmt_task {
 128         struct iscsi_hdr        hdr;
 129         char                    hdrext[sizeof(__u32)]; /* Header-Digest */
 130         int                     xmstate;        /* mgmt xmit progress */
 131         struct iscsi_buf        headbuf;        /* header buffer */
 132         struct iscsi_buf        sendbuf;        /* in progress buffer */
 133         int                     sent;
 134 };
 135
 136 struct iscsi_r2t_info {
 137         __be32                  ttt;            /* copied from R2T */
 138         __be32                  exp_statsn;     /* copied from R2T */
 139         uint32_t                data_length;    /* copied from R2T */
 140         uint32_t                data_offset;    /* copied from R2T */
 141         struct iscsi_buf        headbuf;        /* Data-Out Header Buffer */
 142         struct iscsi_buf        sendbuf;        /* Data-Out in progress buffer*/
 143         int                     sent;           /* R2T sequence progress */
 144         int                     data_count;     /* DATA-Out payload progress */
 145         struct scatterlist      *sg;            /* per-R2T SG list */
 146         int                     solicit_datasn;
 147         struct iscsi_data_task   *dtask;        /* which data task */
 148 };
 149
 150 struct iscsi_tcp_cmd_task {
 151         struct iscsi_cmd        hdr;
 152         char                    hdrext[4*sizeof(__u16)+ /* AHS */
 153                                     sizeof(__u32)];     /* HeaderDigest */
 154         char                    pad[ISCSI_PAD_LEN];
 155         int                     pad_count;              /* padded bytes */
 156         struct iscsi_buf        headbuf;                /* header buf (xmit) */
 157         struct iscsi_buf        sendbuf;                /* in progress buffer*/
 158         int                     xmstate;                /* xmit xtate machine */
 159         int                     sent;
 160         struct scatterlist      *sg;                    /* per-cmd SG list  */
 161         struct scatterlist      *bad_sg;                /* assert statement */
 162         int                     sg_count;               /* SG's to process  */
 163         uint32_t                exp_r2tsn;
 164         int                     r2t_data_count;         /* R2T Data-Out bytes */
 165         int                     data_offset;
 166         struct iscsi_r2t_info   *r2t;                   /* in progress R2T    */
 167         struct iscsi_queue      r2tpool;
 168         struct kfifo            *r2tqueue;
 169         struct iscsi_r2t_info   **r2ts;
 170         struct list_head        dataqueue;              /* Data-Out dataqueue */
 171         mempool_t               *datapool;
 172         uint32_t                datadigest;             /* for recover digest */
 173         int                     digest_count;
 174         uint32_t                immdigest;              /* for imm data */
 175         struct iscsi_buf        immbuf;                 /* for imm data digest */
 176         struct iscsi_data_task   *dtask;                /* data task in progress*/
 177         int                     digest_offset;          /* for partial buff digest */
 178 };
 179
 180 #endif /* ISCSI_H */