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 #define IN_PROGRESS_PAD_RECV            0x4
  33
  34 /* xmit state machine */
  35 #define XMSTATE_VALUE_IDLE                      0
  36 #define XMSTATE_BIT_CMD_HDR_INIT                0
  37 #define XMSTATE_BIT_CMD_HDR_XMIT                1
  38 #define XMSTATE_BIT_IMM_HDR                     2
  39 #define XMSTATE_BIT_IMM_DATA                    3
  40 #define XMSTATE_BIT_UNS_INIT                    4
  41 #define XMSTATE_BIT_UNS_HDR                     5
  42 #define XMSTATE_BIT_UNS_DATA                    6
  43 #define XMSTATE_BIT_SOL_HDR                     7
  44 #define XMSTATE_BIT_SOL_DATA                    8
  45 #define XMSTATE_BIT_W_PAD                       9
  46 #define XMSTATE_BIT_W_RESEND_PAD                10
  47 #define XMSTATE_BIT_W_RESEND_DATA_DIGEST        11
  48 #define XMSTATE_BIT_IMM_HDR_INIT                12
  49 #define XMSTATE_BIT_SOL_HDR_INIT                13
  50
  51 #define ISCSI_PAD_LEN                   4
  52 #define ISCSI_SG_TABLESIZE              SG_ALL
  53 #define ISCSI_TCP_MAX_CMD_LEN           16
  54
  55 struct crypto_hash;
  56 struct socket;
  57
  58 /* Socket connection recieve helper */
  59 struct iscsi_tcp_recv {
  60         struct iscsi_hdr        *hdr;
  61         struct sk_buff          *skb;
  62         int                     offset;
  63         int                     len;
  64         int                     hdr_offset;
  65         int                     copy;
  66         int                     copied;
  67         int                     padding;
  68         struct iscsi_cmd_task   *ctask;         /* current cmd in progress */
  69
  70         /* copied and flipped values */
  71         int                     datalen;
  72         int                     datadgst;
  73         char                    zero_copy_hdr;
  74 };
  75
  76 struct iscsi_tcp_conn {
  77         struct iscsi_conn       *iscsi_conn;
  78         struct socket           *sock;
  79         struct iscsi_hdr        hdr;            /* header placeholder */
  80         char                    hdrext[4*sizeof(__u16) +
  81                                     sizeof(__u32)];
  82         int                     data_copied;
  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         /* control data */
  90         struct iscsi_tcp_recv   in;             /* TCP receive context */
  91         int                     in_progress;    /* connection state machine */
  92
  93         /* old values for socket callbacks */
  94         void                    (*old_data_ready)(struct sock *, int);
  95         void                    (*old_state_change)(struct sock *);
  96         void                    (*old_write_space)(struct sock *);
  97
  98         /* data and header digests */
  99         struct hash_desc        tx_hash;        /* CRC32C (Tx) */
 100         struct hash_desc        rx_hash;        /* CRC32C (Rx) */
 101
 102         /* MIB custom statistics */
 103         uint32_t                sendpage_failures_cnt;
 104         uint32_t                discontiguous_hdr_cnt;
 105
 106         ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
 107 };
 108
 109 struct iscsi_buf {
 110         struct scatterlist      sg;
 111         unsigned int            sent;
 112         char                    use_sendmsg;
 113 };
 114
 115 struct iscsi_data_task {
 116         struct iscsi_data       hdr;                    /* PDU */
 117         char                    hdrext[sizeof(__u32)];  /* Header-Digest */
 118         struct iscsi_buf        digestbuf;              /* digest buffer */
 119         uint32_t                digest;                 /* data digest */
 120 };
 121
 122 struct iscsi_tcp_mgmt_task {
 123         struct iscsi_hdr        hdr;
 124         char                    hdrext[sizeof(__u32)]; /* Header-Digest */
 125         unsigned long           xmstate;        /* mgmt xmit progress */
 126         struct iscsi_buf        headbuf;        /* header buffer */
 127         struct iscsi_buf        sendbuf;        /* in progress buffer */
 128         int                     sent;
 129 };
 130
 131 struct iscsi_r2t_info {
 132         __be32                  ttt;            /* copied from R2T */
 133         __be32                  exp_statsn;     /* copied from R2T */
 134         uint32_t                data_length;    /* copied from R2T */
 135         uint32_t                data_offset;    /* copied from R2T */
 136         struct iscsi_buf        headbuf;        /* Data-Out Header Buffer */
 137         struct iscsi_buf        sendbuf;        /* Data-Out in progress buffer*/
 138         int                     sent;           /* R2T sequence progress */
 139         int                     data_count;     /* DATA-Out payload progress */
 140         struct scatterlist      *sg;            /* per-R2T SG list */
 141         int                     solicit_datasn;
 142         struct iscsi_data_task   dtask;        /* which data task */
 143 };
 144
 145 struct iscsi_tcp_cmd_task {
 146         struct iscsi_cmd        hdr;
 147         char                    hdrext[4*sizeof(__u16)+ /* AHS */
 148                                     sizeof(__u32)];     /* HeaderDigest */
 149         char                    pad[ISCSI_PAD_LEN];
 150         int                     pad_count;              /* padded bytes */
 151         struct iscsi_buf        headbuf;                /* header buf (xmit) */
 152         struct iscsi_buf        sendbuf;                /* in progress buffer*/
 153         unsigned long           xmstate;                /* xmit xtate machine */
 154         int                     sent;
 155         struct scatterlist      *sg;                    /* per-cmd SG list  */
 156         struct scatterlist      *bad_sg;                /* assert statement */
 157         int                     sg_count;               /* SG's to process  */
 158         uint32_t                exp_datasn;             /* expected target's R2TSN/DataSN */
 159         int                     data_offset;
 160         struct iscsi_r2t_info   *r2t;                   /* in progress R2T    */
 161         struct iscsi_queue      r2tpool;
 162         struct kfifo            *r2tqueue;
 163         struct iscsi_r2t_info   **r2ts;
 164         int                     digest_count;
 165         uint32_t                immdigest;              /* for imm data */
 166         struct iscsi_buf        immbuf;                 /* for imm data digest */
 167         struct iscsi_data_task  unsol_dtask;    /* unsol data task */
 168 };
 169
 170 #endif /* ISCSI_H */