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   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_CMD_HDR_INIT            0x1
  36 #define XMSTATE_CMD_HDR_XMIT            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_W_RESEND_PAD            0x400
  46 #define XMSTATE_W_RESEND_DATA_DIGEST    0x800
  47 #define XMSTATE_IMM_HDR_INIT            0x1000
  48 #define XMSTATE_SOL_HDR_INIT            0x2000
  49
  50 #define ISCSI_PAD_LEN                   4
  51 #define ISCSI_SG_TABLESIZE              SG_ALL
  52 #define ISCSI_TCP_MAX_CMD_LEN           16
  53
  54 struct crypto_hash;
  55 struct socket;
  56
  57 /* Socket connection recieve helper */
  58 struct iscsi_tcp_recv {
  59         struct iscsi_hdr        *hdr;
  60         struct sk_buff          *skb;
  61         int                     offset;
  62         int                     len;
  63         int                     hdr_offset;
  64         int                     copy;
  65         int                     copied;
  66         int                     padding;
  67         struct iscsi_cmd_task   *ctask;         /* current cmd in progress */
  68
  69         /* copied and flipped values */
  70         int                     datalen;
  71         int                     datadgst;
  72         char                    zero_copy_hdr;
  73 };
  74
  75 struct iscsi_tcp_conn {
  76         struct iscsi_conn       *iscsi_conn;
  77         struct socket           *sock;
  78         struct iscsi_hdr        hdr;            /* header placeholder */
  79         char                    hdrext[4*sizeof(__u16) +
  80                                     sizeof(__u32)];
  81         int                     data_copied;
  82         int                     stop_stage;     /* conn_stop() flag: *
  83                                                  * stop to recover,  *
  84                                                  * stop to terminate */
  85         /* iSCSI connection-wide sequencing */
  86         int                     hdr_size;       /* PDU header size */
  87
  88         /* control data */
  89         struct iscsi_tcp_recv   in;             /* TCP receive context */
  90         int                     in_progress;    /* connection state machine */
  91
  92         /* old values for socket callbacks */
  93         void                    (*old_data_ready)(struct sock *, int);
  94         void                    (*old_state_change)(struct sock *);
  95         void                    (*old_write_space)(struct sock *);
  96
  97         /* data and header digests */
  98         struct hash_desc        tx_hash;        /* CRC32C (Tx) */
  99         struct hash_desc        rx_hash;        /* CRC32C (Rx) */
 100
 101         /* MIB custom statistics */
 102         uint32_t                sendpage_failures_cnt;
 103         uint32_t                discontiguous_hdr_cnt;
 104
 105         ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
 106 };
 107
 108 struct iscsi_buf {
 109         struct scatterlist      sg;
 110         unsigned int            sent;
 111         char                    use_sendmsg;
 112 };
 113
 114 struct iscsi_data_task {
 115         struct iscsi_data       hdr;                    /* PDU */
 116         char                    hdrext[sizeof(__u32)];  /* Header-Digest */
 117         struct iscsi_buf        digestbuf;              /* digest buffer */
 118         uint32_t                digest;                 /* data digest */
 119 };
 120
 121 struct iscsi_tcp_mgmt_task {
 122         struct iscsi_hdr        hdr;
 123         char                    hdrext[sizeof(__u32)]; /* Header-Digest */
 124         int                     xmstate;        /* mgmt xmit progress */
 125         struct iscsi_buf        headbuf;        /* header buffer */
 126         struct iscsi_buf        sendbuf;        /* in progress buffer */
 127         int                     sent;
 128 };
 129
 130 struct iscsi_r2t_info {
 131         __be32                  ttt;            /* copied from R2T */
 132         __be32                  exp_statsn;     /* copied from R2T */
 133         uint32_t                data_length;    /* copied from R2T */
 134         uint32_t                data_offset;    /* copied from R2T */
 135         struct iscsi_buf        headbuf;        /* Data-Out Header Buffer */
 136         struct iscsi_buf        sendbuf;        /* Data-Out in progress buffer*/
 137         int                     sent;           /* R2T sequence progress */
 138         int                     data_count;     /* DATA-Out payload progress */
 139         struct scatterlist      *sg;            /* per-R2T SG list */
 140         int                     solicit_datasn;
 141         struct iscsi_data_task   dtask;        /* which data task */
 142 };
 143
 144 struct iscsi_tcp_cmd_task {
 145         struct iscsi_cmd        hdr;
 146         char                    hdrext[4*sizeof(__u16)+ /* AHS */
 147                                     sizeof(__u32)];     /* HeaderDigest */
 148         char                    pad[ISCSI_PAD_LEN];
 149         int                     pad_count;              /* padded bytes */
 150         struct iscsi_buf        headbuf;                /* header buf (xmit) */
 151         struct iscsi_buf        sendbuf;                /* in progress buffer*/
 152         int                     xmstate;                /* xmit xtate machine */
 153         int                     sent;
 154         struct scatterlist      *sg;                    /* per-cmd SG list  */
 155         struct scatterlist      *bad_sg;                /* assert statement */
 156         int                     sg_count;               /* SG's to process  */
 157         uint32_t                exp_datasn;             /* expected target's R2TSN/DataSN */
 158         int                     data_offset;
 159         struct iscsi_r2t_info   *r2t;                   /* in progress R2T    */
 160         struct iscsi_queue      r2tpool;
 161         struct kfifo            *r2tqueue;
 162         struct iscsi_r2t_info   **r2ts;
 163         int                     digest_count;
 164         uint32_t                immdigest;              /* for imm data */
 165         struct iscsi_buf        immbuf;                 /* for imm data digest */
 166         struct iscsi_data_task  unsol_dtask;    /* unsol data task */
 167 };
 168
 169 #endif /* ISCSI_H */