linux/drivers/scsi/iscsi_tcp.c
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   1/*
   2 * iSCSI Initiator over TCP/IP Data-Path
   3 *
   4 * Copyright (C) 2004 Dmitry Yusupov
   5 * Copyright (C) 2004 Alex Aizman
   6 * Copyright (C) 2005 - 2006 Mike Christie
   7 * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
   8 * maintained by open-iscsi@googlegroups.com
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published
  12 * by the Free Software Foundation; either version 2 of the License, or
  13 * (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful, but
  16 * WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18 * General Public License for more details.
  19 *
  20 * See the file COPYING included with this distribution for more details.
  21 *
  22 * Credits:
  23 *      Christoph Hellwig
  24 *      FUJITA Tomonori
  25 *      Arne Redlich
  26 *      Zhenyu Wang
  27 */
  28
  29#include <linux/types.h>
  30#include <linux/inet.h>
  31#include <linux/slab.h>
  32#include <linux/file.h>
  33#include <linux/blkdev.h>
  34#include <linux/crypto.h>
  35#include <linux/delay.h>
  36#include <linux/kfifo.h>
  37#include <linux/scatterlist.h>
  38#include <linux/module.h>
  39#include <net/tcp.h>
  40#include <scsi/scsi_cmnd.h>
  41#include <scsi/scsi_device.h>
  42#include <scsi/scsi_host.h>
  43#include <scsi/scsi.h>
  44#include <scsi/scsi_transport_iscsi.h>
  45
  46#include "iscsi_tcp.h"
  47
  48MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
  49              "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
  50              "Alex Aizman <itn780@yahoo.com>");
  51MODULE_DESCRIPTION("iSCSI/TCP data-path");
  52MODULE_LICENSE("GPL");
  53
  54static struct scsi_transport_template *iscsi_sw_tcp_scsi_transport;
  55static struct scsi_host_template iscsi_sw_tcp_sht;
  56static struct iscsi_transport iscsi_sw_tcp_transport;
  57
  58static unsigned int iscsi_max_lun = ~0;
  59module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
  60
  61static int iscsi_sw_tcp_dbg;
  62module_param_named(debug_iscsi_tcp, iscsi_sw_tcp_dbg, int,
  63                   S_IRUGO | S_IWUSR);
  64MODULE_PARM_DESC(debug_iscsi_tcp, "Turn on debugging for iscsi_tcp module "
  65                 "Set to 1 to turn on, and zero to turn off. Default is off.");
  66
  67#define ISCSI_SW_TCP_DBG(_conn, dbg_fmt, arg...)                \
  68        do {                                                    \
  69                if (iscsi_sw_tcp_dbg)                           \
  70                        iscsi_conn_printk(KERN_INFO, _conn,     \
  71                                             "%s " dbg_fmt,     \
  72                                             __func__, ##arg);  \
  73        } while (0);
  74
  75
  76/**
  77 * iscsi_sw_tcp_recv - TCP receive in sendfile fashion
  78 * @rd_desc: read descriptor
  79 * @skb: socket buffer
  80 * @offset: offset in skb
  81 * @len: skb->len - offset
  82 */
  83static int iscsi_sw_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
  84                             unsigned int offset, size_t len)
  85{
  86        struct iscsi_conn *conn = rd_desc->arg.data;
  87        unsigned int consumed, total_consumed = 0;
  88        int status;
  89
  90        ISCSI_SW_TCP_DBG(conn, "in %d bytes\n", skb->len - offset);
  91
  92        do {
  93                status = 0;
  94                consumed = iscsi_tcp_recv_skb(conn, skb, offset, 0, &status);
  95                offset += consumed;
  96                total_consumed += consumed;
  97        } while (consumed != 0 && status != ISCSI_TCP_SKB_DONE);
  98
  99        ISCSI_SW_TCP_DBG(conn, "read %d bytes status %d\n",
 100                         skb->len - offset, status);
 101        return total_consumed;
 102}
 103
 104/**
 105 * iscsi_sw_sk_state_check - check socket state
 106 * @sk: socket
 107 *
 108 * If the socket is in CLOSE or CLOSE_WAIT we should
 109 * not close the connection if there is still some
 110 * data pending.
 111 *
 112 * Must be called with sk_callback_lock.
 113 */
 114static inline int iscsi_sw_sk_state_check(struct sock *sk)
 115{
 116        struct iscsi_conn *conn = sk->sk_user_data;
 117
 118        if ((sk->sk_state == TCP_CLOSE_WAIT || sk->sk_state == TCP_CLOSE) &&
 119            !atomic_read(&sk->sk_rmem_alloc)) {
 120                ISCSI_SW_TCP_DBG(conn, "TCP_CLOSE|TCP_CLOSE_WAIT\n");
 121                iscsi_conn_failure(conn, ISCSI_ERR_TCP_CONN_CLOSE);
 122                return -ECONNRESET;
 123        }
 124        return 0;
 125}
 126
 127static void iscsi_sw_tcp_data_ready(struct sock *sk, int flag)
 128{
 129        struct iscsi_conn *conn;
 130        struct iscsi_tcp_conn *tcp_conn;
 131        read_descriptor_t rd_desc;
 132
 133        read_lock(&sk->sk_callback_lock);
 134        conn = sk->sk_user_data;
 135        if (!conn) {
 136                read_unlock(&sk->sk_callback_lock);
 137                return;
 138        }
 139        tcp_conn = conn->dd_data;
 140
 141        /*
 142         * Use rd_desc to pass 'conn' to iscsi_tcp_recv.
 143         * We set count to 1 because we want the network layer to
 144         * hand us all the skbs that are available. iscsi_tcp_recv
 145         * handled pdus that cross buffers or pdus that still need data.
 146         */
 147        rd_desc.arg.data = conn;
 148        rd_desc.count = 1;
 149        tcp_read_sock(sk, &rd_desc, iscsi_sw_tcp_recv);
 150
 151        iscsi_sw_sk_state_check(sk);
 152
 153        /* If we had to (atomically) map a highmem page,
 154         * unmap it now. */
 155        iscsi_tcp_segment_unmap(&tcp_conn->in.segment);
 156        read_unlock(&sk->sk_callback_lock);
 157}
 158
 159static void iscsi_sw_tcp_state_change(struct sock *sk)
 160{
 161        struct iscsi_tcp_conn *tcp_conn;
 162        struct iscsi_sw_tcp_conn *tcp_sw_conn;
 163        struct iscsi_conn *conn;
 164        struct iscsi_session *session;
 165        void (*old_state_change)(struct sock *);
 166
 167        read_lock(&sk->sk_callback_lock);
 168        conn = sk->sk_user_data;
 169        if (!conn) {
 170                read_unlock(&sk->sk_callback_lock);
 171                return;
 172        }
 173        session = conn->session;
 174
 175        iscsi_sw_sk_state_check(sk);
 176
 177        tcp_conn = conn->dd_data;
 178        tcp_sw_conn = tcp_conn->dd_data;
 179        old_state_change = tcp_sw_conn->old_state_change;
 180
 181        read_unlock(&sk->sk_callback_lock);
 182
 183        old_state_change(sk);
 184}
 185
 186/**
 187 * iscsi_write_space - Called when more output buffer space is available
 188 * @sk: socket space is available for
 189 **/
 190static void iscsi_sw_tcp_write_space(struct sock *sk)
 191{
 192        struct iscsi_conn *conn;
 193        struct iscsi_tcp_conn *tcp_conn;
 194        struct iscsi_sw_tcp_conn *tcp_sw_conn;
 195        void (*old_write_space)(struct sock *);
 196
 197        read_lock_bh(&sk->sk_callback_lock);
 198        conn = sk->sk_user_data;
 199        if (!conn) {
 200                read_unlock_bh(&sk->sk_callback_lock);
 201                return;
 202        }
 203
 204        tcp_conn = conn->dd_data;
 205        tcp_sw_conn = tcp_conn->dd_data;
 206        old_write_space = tcp_sw_conn->old_write_space;
 207        read_unlock_bh(&sk->sk_callback_lock);
 208
 209        old_write_space(sk);
 210
 211        ISCSI_SW_TCP_DBG(conn, "iscsi_write_space\n");
 212        iscsi_conn_queue_work(conn);
 213}
 214
 215static void iscsi_sw_tcp_conn_set_callbacks(struct iscsi_conn *conn)
 216{
 217        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 218        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 219        struct sock *sk = tcp_sw_conn->sock->sk;
 220
 221        /* assign new callbacks */
 222        write_lock_bh(&sk->sk_callback_lock);
 223        sk->sk_user_data = conn;
 224        tcp_sw_conn->old_data_ready = sk->sk_data_ready;
 225        tcp_sw_conn->old_state_change = sk->sk_state_change;
 226        tcp_sw_conn->old_write_space = sk->sk_write_space;
 227        sk->sk_data_ready = iscsi_sw_tcp_data_ready;
 228        sk->sk_state_change = iscsi_sw_tcp_state_change;
 229        sk->sk_write_space = iscsi_sw_tcp_write_space;
 230        write_unlock_bh(&sk->sk_callback_lock);
 231}
 232
 233static void
 234iscsi_sw_tcp_conn_restore_callbacks(struct iscsi_conn *conn)
 235{
 236        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 237        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 238        struct sock *sk = tcp_sw_conn->sock->sk;
 239
 240        /* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
 241        write_lock_bh(&sk->sk_callback_lock);
 242        sk->sk_user_data    = NULL;
 243        sk->sk_data_ready   = tcp_sw_conn->old_data_ready;
 244        sk->sk_state_change = tcp_sw_conn->old_state_change;
 245        sk->sk_write_space  = tcp_sw_conn->old_write_space;
 246        sk->sk_no_check  = 0;
 247        write_unlock_bh(&sk->sk_callback_lock);
 248}
 249
 250/**
 251 * iscsi_sw_tcp_xmit_segment - transmit segment
 252 * @tcp_conn: the iSCSI TCP connection
 253 * @segment: the buffer to transmnit
 254 *
 255 * This function transmits as much of the buffer as
 256 * the network layer will accept, and returns the number of
 257 * bytes transmitted.
 258 *
 259 * If CRC hashing is enabled, the function will compute the
 260 * hash as it goes. When the entire segment has been transmitted,
 261 * it will retrieve the hash value and send it as well.
 262 */
 263static int iscsi_sw_tcp_xmit_segment(struct iscsi_tcp_conn *tcp_conn,
 264                                     struct iscsi_segment *segment)
 265{
 266        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 267        struct socket *sk = tcp_sw_conn->sock;
 268        unsigned int copied = 0;
 269        int r = 0;
 270
 271        while (!iscsi_tcp_segment_done(tcp_conn, segment, 0, r)) {
 272                struct scatterlist *sg;
 273                unsigned int offset, copy;
 274                int flags = 0;
 275
 276                r = 0;
 277                offset = segment->copied;
 278                copy = segment->size - offset;
 279
 280                if (segment->total_copied + segment->size < segment->total_size)
 281                        flags |= MSG_MORE;
 282
 283                /* Use sendpage if we can; else fall back to sendmsg */
 284                if (!segment->data) {
 285                        sg = segment->sg;
 286                        offset += segment->sg_offset + sg->offset;
 287                        r = tcp_sw_conn->sendpage(sk, sg_page(sg), offset,
 288                                                  copy, flags);
 289                } else {
 290                        struct msghdr msg = { .msg_flags = flags };
 291                        struct kvec iov = {
 292                                .iov_base = segment->data + offset,
 293                                .iov_len = copy
 294                        };
 295
 296                        r = kernel_sendmsg(sk, &msg, &iov, 1, copy);
 297                }
 298
 299                if (r < 0) {
 300                        iscsi_tcp_segment_unmap(segment);
 301                        return r;
 302                }
 303                copied += r;
 304        }
 305        return copied;
 306}
 307
 308/**
 309 * iscsi_sw_tcp_xmit - TCP transmit
 310 **/
 311static int iscsi_sw_tcp_xmit(struct iscsi_conn *conn)
 312{
 313        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 314        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 315        struct iscsi_segment *segment = &tcp_sw_conn->out.segment;
 316        unsigned int consumed = 0;
 317        int rc = 0;
 318
 319        while (1) {
 320                rc = iscsi_sw_tcp_xmit_segment(tcp_conn, segment);
 321                /*
 322                 * We may not have been able to send data because the conn
 323                 * is getting stopped. libiscsi will know so propagate err
 324                 * for it to do the right thing.
 325                 */
 326                if (rc == -EAGAIN)
 327                        return rc;
 328                else if (rc < 0) {
 329                        rc = ISCSI_ERR_XMIT_FAILED;
 330                        goto error;
 331                } else if (rc == 0)
 332                        break;
 333
 334                consumed += rc;
 335
 336                if (segment->total_copied >= segment->total_size) {
 337                        if (segment->done != NULL) {
 338                                rc = segment->done(tcp_conn, segment);
 339                                if (rc != 0)
 340                                        goto error;
 341                        }
 342                }
 343        }
 344
 345        ISCSI_SW_TCP_DBG(conn, "xmit %d bytes\n", consumed);
 346
 347        conn->txdata_octets += consumed;
 348        return consumed;
 349
 350error:
 351        /* Transmit error. We could initiate error recovery
 352         * here. */
 353        ISCSI_SW_TCP_DBG(conn, "Error sending PDU, errno=%d\n", rc);
 354        iscsi_conn_failure(conn, rc);
 355        return -EIO;
 356}
 357
 358/**
 359 * iscsi_tcp_xmit_qlen - return the number of bytes queued for xmit
 360 */
 361static inline int iscsi_sw_tcp_xmit_qlen(struct iscsi_conn *conn)
 362{
 363        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 364        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 365        struct iscsi_segment *segment = &tcp_sw_conn->out.segment;
 366
 367        return segment->total_copied - segment->total_size;
 368}
 369
 370static int iscsi_sw_tcp_pdu_xmit(struct iscsi_task *task)
 371{
 372        struct iscsi_conn *conn = task->conn;
 373        unsigned long pflags = current->flags;
 374        int rc = 0;
 375
 376        current->flags |= PF_MEMALLOC;
 377
 378        while (iscsi_sw_tcp_xmit_qlen(conn)) {
 379                rc = iscsi_sw_tcp_xmit(conn);
 380                if (rc == 0) {
 381                        rc = -EAGAIN;
 382                        break;
 383                }
 384                if (rc < 0)
 385                        break;
 386                rc = 0;
 387        }
 388
 389        tsk_restore_flags(current, pflags, PF_MEMALLOC);
 390        return rc;
 391}
 392
 393/*
 394 * This is called when we're done sending the header.
 395 * Simply copy the data_segment to the send segment, and return.
 396 */
 397static int iscsi_sw_tcp_send_hdr_done(struct iscsi_tcp_conn *tcp_conn,
 398                                      struct iscsi_segment *segment)
 399{
 400        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 401
 402        tcp_sw_conn->out.segment = tcp_sw_conn->out.data_segment;
 403        ISCSI_SW_TCP_DBG(tcp_conn->iscsi_conn,
 404                         "Header done. Next segment size %u total_size %u\n",
 405                         tcp_sw_conn->out.segment.size,
 406                         tcp_sw_conn->out.segment.total_size);
 407        return 0;
 408}
 409
 410static void iscsi_sw_tcp_send_hdr_prep(struct iscsi_conn *conn, void *hdr,
 411                                       size_t hdrlen)
 412{
 413        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 414        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 415
 416        ISCSI_SW_TCP_DBG(conn, "%s\n", conn->hdrdgst_en ?
 417                         "digest enabled" : "digest disabled");
 418
 419        /* Clear the data segment - needs to be filled in by the
 420         * caller using iscsi_tcp_send_data_prep() */
 421        memset(&tcp_sw_conn->out.data_segment, 0,
 422               sizeof(struct iscsi_segment));
 423
 424        /* If header digest is enabled, compute the CRC and
 425         * place the digest into the same buffer. We make
 426         * sure that both iscsi_tcp_task and mtask have
 427         * sufficient room.
 428         */
 429        if (conn->hdrdgst_en) {
 430                iscsi_tcp_dgst_header(&tcp_sw_conn->tx_hash, hdr, hdrlen,
 431                                      hdr + hdrlen);
 432                hdrlen += ISCSI_DIGEST_SIZE;
 433        }
 434
 435        /* Remember header pointer for later, when we need
 436         * to decide whether there's a payload to go along
 437         * with the header. */
 438        tcp_sw_conn->out.hdr = hdr;
 439
 440        iscsi_segment_init_linear(&tcp_sw_conn->out.segment, hdr, hdrlen,
 441                                  iscsi_sw_tcp_send_hdr_done, NULL);
 442}
 443
 444/*
 445 * Prepare the send buffer for the payload data.
 446 * Padding and checksumming will all be taken care
 447 * of by the iscsi_segment routines.
 448 */
 449static int
 450iscsi_sw_tcp_send_data_prep(struct iscsi_conn *conn, struct scatterlist *sg,
 451                            unsigned int count, unsigned int offset,
 452                            unsigned int len)
 453{
 454        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 455        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 456        struct hash_desc *tx_hash = NULL;
 457        unsigned int hdr_spec_len;
 458
 459        ISCSI_SW_TCP_DBG(conn, "offset=%d, datalen=%d %s\n", offset, len,
 460                         conn->datadgst_en ?
 461                         "digest enabled" : "digest disabled");
 462
 463        /* Make sure the datalen matches what the caller
 464           said he would send. */
 465        hdr_spec_len = ntoh24(tcp_sw_conn->out.hdr->dlength);
 466        WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
 467
 468        if (conn->datadgst_en)
 469                tx_hash = &tcp_sw_conn->tx_hash;
 470
 471        return iscsi_segment_seek_sg(&tcp_sw_conn->out.data_segment,
 472                                     sg, count, offset, len,
 473                                     NULL, tx_hash);
 474}
 475
 476static void
 477iscsi_sw_tcp_send_linear_data_prep(struct iscsi_conn *conn, void *data,
 478                                   size_t len)
 479{
 480        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 481        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 482        struct hash_desc *tx_hash = NULL;
 483        unsigned int hdr_spec_len;
 484
 485        ISCSI_SW_TCP_DBG(conn, "datalen=%zd %s\n", len, conn->datadgst_en ?
 486                         "digest enabled" : "digest disabled");
 487
 488        /* Make sure the datalen matches what the caller
 489           said he would send. */
 490        hdr_spec_len = ntoh24(tcp_sw_conn->out.hdr->dlength);
 491        WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
 492
 493        if (conn->datadgst_en)
 494                tx_hash = &tcp_sw_conn->tx_hash;
 495
 496        iscsi_segment_init_linear(&tcp_sw_conn->out.data_segment,
 497                                data, len, NULL, tx_hash);
 498}
 499
 500static int iscsi_sw_tcp_pdu_init(struct iscsi_task *task,
 501                                 unsigned int offset, unsigned int count)
 502{
 503        struct iscsi_conn *conn = task->conn;
 504        int err = 0;
 505
 506        iscsi_sw_tcp_send_hdr_prep(conn, task->hdr, task->hdr_len);
 507
 508        if (!count)
 509                return 0;
 510
 511        if (!task->sc)
 512                iscsi_sw_tcp_send_linear_data_prep(conn, task->data, count);
 513        else {
 514                struct scsi_data_buffer *sdb = scsi_out(task->sc);
 515
 516                err = iscsi_sw_tcp_send_data_prep(conn, sdb->table.sgl,
 517                                                  sdb->table.nents, offset,
 518                                                  count);
 519        }
 520
 521        if (err) {
 522                /* got invalid offset/len */
 523                return -EIO;
 524        }
 525        return 0;
 526}
 527
 528static int iscsi_sw_tcp_pdu_alloc(struct iscsi_task *task, uint8_t opcode)
 529{
 530        struct iscsi_tcp_task *tcp_task = task->dd_data;
 531
 532        task->hdr = task->dd_data + sizeof(*tcp_task);
 533        task->hdr_max = sizeof(struct iscsi_sw_tcp_hdrbuf) - ISCSI_DIGEST_SIZE;
 534        return 0;
 535}
 536
 537static struct iscsi_cls_conn *
 538iscsi_sw_tcp_conn_create(struct iscsi_cls_session *cls_session,
 539                         uint32_t conn_idx)
 540{
 541        struct iscsi_conn *conn;
 542        struct iscsi_cls_conn *cls_conn;
 543        struct iscsi_tcp_conn *tcp_conn;
 544        struct iscsi_sw_tcp_conn *tcp_sw_conn;
 545
 546        cls_conn = iscsi_tcp_conn_setup(cls_session, sizeof(*tcp_sw_conn),
 547                                        conn_idx);
 548        if (!cls_conn)
 549                return NULL;
 550        conn = cls_conn->dd_data;
 551        tcp_conn = conn->dd_data;
 552        tcp_sw_conn = tcp_conn->dd_data;
 553
 554        tcp_sw_conn->tx_hash.tfm = crypto_alloc_hash("crc32c", 0,
 555                                                     CRYPTO_ALG_ASYNC);
 556        tcp_sw_conn->tx_hash.flags = 0;
 557        if (IS_ERR(tcp_sw_conn->tx_hash.tfm))
 558                goto free_conn;
 559
 560        tcp_sw_conn->rx_hash.tfm = crypto_alloc_hash("crc32c", 0,
 561                                                     CRYPTO_ALG_ASYNC);
 562        tcp_sw_conn->rx_hash.flags = 0;
 563        if (IS_ERR(tcp_sw_conn->rx_hash.tfm))
 564                goto free_tx_tfm;
 565        tcp_conn->rx_hash = &tcp_sw_conn->rx_hash;
 566
 567        return cls_conn;
 568
 569free_tx_tfm:
 570        crypto_free_hash(tcp_sw_conn->tx_hash.tfm);
 571free_conn:
 572        iscsi_conn_printk(KERN_ERR, conn,
 573                          "Could not create connection due to crc32c "
 574                          "loading error. Make sure the crc32c "
 575                          "module is built as a module or into the "
 576                          "kernel\n");
 577        iscsi_tcp_conn_teardown(cls_conn);
 578        return NULL;
 579}
 580
 581static void iscsi_sw_tcp_release_conn(struct iscsi_conn *conn)
 582{
 583        struct iscsi_session *session = conn->session;
 584        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 585        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 586        struct socket *sock = tcp_sw_conn->sock;
 587
 588        if (!sock)
 589                return;
 590
 591        sock_hold(sock->sk);
 592        iscsi_sw_tcp_conn_restore_callbacks(conn);
 593        sock_put(sock->sk);
 594
 595        spin_lock_bh(&session->lock);
 596        tcp_sw_conn->sock = NULL;
 597        spin_unlock_bh(&session->lock);
 598        sockfd_put(sock);
 599}
 600
 601static void iscsi_sw_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
 602{
 603        struct iscsi_conn *conn = cls_conn->dd_data;
 604        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 605        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 606
 607        iscsi_sw_tcp_release_conn(conn);
 608
 609        if (tcp_sw_conn->tx_hash.tfm)
 610                crypto_free_hash(tcp_sw_conn->tx_hash.tfm);
 611        if (tcp_sw_conn->rx_hash.tfm)
 612                crypto_free_hash(tcp_sw_conn->rx_hash.tfm);
 613
 614        iscsi_tcp_conn_teardown(cls_conn);
 615}
 616
 617static void iscsi_sw_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
 618{
 619        struct iscsi_conn *conn = cls_conn->dd_data;
 620        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 621        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 622        struct socket *sock = tcp_sw_conn->sock;
 623
 624        /* userspace may have goofed up and not bound us */
 625        if (!sock)
 626                return;
 627
 628        sock->sk->sk_err = EIO;
 629        wake_up_interruptible(sk_sleep(sock->sk));
 630
 631        /* stop xmit side */
 632        iscsi_suspend_tx(conn);
 633
 634        /* stop recv side and release socket */
 635        iscsi_sw_tcp_release_conn(conn);
 636
 637        iscsi_conn_stop(cls_conn, flag);
 638}
 639
 640static int
 641iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
 642                       struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
 643                       int is_leading)
 644{
 645        struct iscsi_session *session = cls_session->dd_data;
 646        struct iscsi_conn *conn = cls_conn->dd_data;
 647        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 648        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 649        struct sock *sk;
 650        struct socket *sock;
 651        int err;
 652
 653        /* lookup for existing socket */
 654        sock = sockfd_lookup((int)transport_eph, &err);
 655        if (!sock) {
 656                iscsi_conn_printk(KERN_ERR, conn,
 657                                  "sockfd_lookup failed %d\n", err);
 658                return -EEXIST;
 659        }
 660
 661        err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
 662        if (err)
 663                goto free_socket;
 664
 665        spin_lock_bh(&session->lock);
 666        /* bind iSCSI connection and socket */
 667        tcp_sw_conn->sock = sock;
 668        spin_unlock_bh(&session->lock);
 669
 670        /* setup Socket parameters */
 671        sk = sock->sk;
 672        sk->sk_reuse = SK_CAN_REUSE;
 673        sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
 674        sk->sk_allocation = GFP_ATOMIC;
 675        sk_set_memalloc(sk);
 676
 677        iscsi_sw_tcp_conn_set_callbacks(conn);
 678        tcp_sw_conn->sendpage = tcp_sw_conn->sock->ops->sendpage;
 679        /*
 680         * set receive state machine into initial state
 681         */
 682        iscsi_tcp_hdr_recv_prep(tcp_conn);
 683        return 0;
 684
 685free_socket:
 686        sockfd_put(sock);
 687        return err;
 688}
 689
 690static int iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn *cls_conn,
 691                                       enum iscsi_param param, char *buf,
 692                                       int buflen)
 693{
 694        struct iscsi_conn *conn = cls_conn->dd_data;
 695        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 696        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 697
 698        switch(param) {
 699        case ISCSI_PARAM_HDRDGST_EN:
 700                iscsi_set_param(cls_conn, param, buf, buflen);
 701                break;
 702        case ISCSI_PARAM_DATADGST_EN:
 703                iscsi_set_param(cls_conn, param, buf, buflen);
 704                tcp_sw_conn->sendpage = conn->datadgst_en ?
 705                        sock_no_sendpage : tcp_sw_conn->sock->ops->sendpage;
 706                break;
 707        case ISCSI_PARAM_MAX_R2T:
 708                return iscsi_tcp_set_max_r2t(conn, buf);
 709        default:
 710                return iscsi_set_param(cls_conn, param, buf, buflen);
 711        }
 712
 713        return 0;
 714}
 715
 716static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
 717                                       enum iscsi_param param, char *buf)
 718{
 719        struct iscsi_conn *conn = cls_conn->dd_data;
 720        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 721        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 722        struct sockaddr_in6 addr;
 723        int rc, len;
 724
 725        switch(param) {
 726        case ISCSI_PARAM_CONN_PORT:
 727        case ISCSI_PARAM_CONN_ADDRESS:
 728                spin_lock_bh(&conn->session->lock);
 729                if (!tcp_sw_conn || !tcp_sw_conn->sock) {
 730                        spin_unlock_bh(&conn->session->lock);
 731                        return -ENOTCONN;
 732                }
 733                rc = kernel_getpeername(tcp_sw_conn->sock,
 734                                        (struct sockaddr *)&addr, &len);
 735                spin_unlock_bh(&conn->session->lock);
 736                if (rc)
 737                        return rc;
 738
 739                return iscsi_conn_get_addr_param((struct sockaddr_storage *)
 740                                                 &addr, param, buf);
 741        default:
 742                return iscsi_conn_get_param(cls_conn, param, buf);
 743        }
 744
 745        return 0;
 746}
 747
 748static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
 749                                       enum iscsi_host_param param, char *buf)
 750{
 751        struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(shost);
 752        struct iscsi_session *session = tcp_sw_host->session;
 753        struct iscsi_conn *conn;
 754        struct iscsi_tcp_conn *tcp_conn;
 755        struct iscsi_sw_tcp_conn *tcp_sw_conn;
 756        struct sockaddr_in6 addr;
 757        int rc, len;
 758
 759        switch (param) {
 760        case ISCSI_HOST_PARAM_IPADDRESS:
 761                spin_lock_bh(&session->lock);
 762                conn = session->leadconn;
 763                if (!conn) {
 764                        spin_unlock_bh(&session->lock);
 765                        return -ENOTCONN;
 766                }
 767                tcp_conn = conn->dd_data;
 768
 769                tcp_sw_conn = tcp_conn->dd_data;
 770                if (!tcp_sw_conn->sock) {
 771                        spin_unlock_bh(&session->lock);
 772                        return -ENOTCONN;
 773                }
 774
 775                rc = kernel_getsockname(tcp_sw_conn->sock,
 776                                        (struct sockaddr *)&addr, &len);
 777                spin_unlock_bh(&session->lock);
 778                if (rc)
 779                        return rc;
 780
 781                return iscsi_conn_get_addr_param((struct sockaddr_storage *)
 782                                                 &addr, param, buf);
 783        default:
 784                return iscsi_host_get_param(shost, param, buf);
 785        }
 786
 787        return 0;
 788}
 789
 790static void
 791iscsi_sw_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
 792                            struct iscsi_stats *stats)
 793{
 794        struct iscsi_conn *conn = cls_conn->dd_data;
 795        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 796        struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
 797
 798        stats->custom_length = 3;
 799        strcpy(stats->custom[0].desc, "tx_sendpage_failures");
 800        stats->custom[0].value = tcp_sw_conn->sendpage_failures_cnt;
 801        strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
 802        stats->custom[1].value = tcp_sw_conn->discontiguous_hdr_cnt;
 803        strcpy(stats->custom[2].desc, "eh_abort_cnt");
 804        stats->custom[2].value = conn->eh_abort_cnt;
 805
 806        iscsi_tcp_conn_get_stats(cls_conn, stats);
 807}
 808
 809static struct iscsi_cls_session *
 810iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
 811                            uint16_t qdepth, uint32_t initial_cmdsn)
 812{
 813        struct iscsi_cls_session *cls_session;
 814        struct iscsi_session *session;
 815        struct iscsi_sw_tcp_host *tcp_sw_host;
 816        struct Scsi_Host *shost;
 817
 818        if (ep) {
 819                printk(KERN_ERR "iscsi_tcp: invalid ep %p.\n", ep);
 820                return NULL;
 821        }
 822
 823        shost = iscsi_host_alloc(&iscsi_sw_tcp_sht,
 824                                 sizeof(struct iscsi_sw_tcp_host), 1);
 825        if (!shost)
 826                return NULL;
 827        shost->transportt = iscsi_sw_tcp_scsi_transport;
 828        shost->cmd_per_lun = qdepth;
 829        shost->max_lun = iscsi_max_lun;
 830        shost->max_id = 0;
 831        shost->max_channel = 0;
 832        shost->max_cmd_len = SCSI_MAX_VARLEN_CDB_SIZE;
 833
 834        if (iscsi_host_add(shost, NULL))
 835                goto free_host;
 836
 837        cls_session = iscsi_session_setup(&iscsi_sw_tcp_transport, shost,
 838                                          cmds_max, 0,
 839                                          sizeof(struct iscsi_tcp_task) +
 840                                          sizeof(struct iscsi_sw_tcp_hdrbuf),
 841                                          initial_cmdsn, 0);
 842        if (!cls_session)
 843                goto remove_host;
 844        session = cls_session->dd_data;
 845        tcp_sw_host = iscsi_host_priv(shost);
 846        tcp_sw_host->session = session;
 847
 848        shost->can_queue = session->scsi_cmds_max;
 849        if (iscsi_tcp_r2tpool_alloc(session))
 850                goto remove_session;
 851        return cls_session;
 852
 853remove_session:
 854        iscsi_session_teardown(cls_session);
 855remove_host:
 856        iscsi_host_remove(shost);
 857free_host:
 858        iscsi_host_free(shost);
 859        return NULL;
 860}
 861
 862static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
 863{
 864        struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
 865
 866        iscsi_tcp_r2tpool_free(cls_session->dd_data);
 867        iscsi_session_teardown(cls_session);
 868
 869        iscsi_host_remove(shost);
 870        iscsi_host_free(shost);
 871}
 872
 873static umode_t iscsi_sw_tcp_attr_is_visible(int param_type, int param)
 874{
 875        switch (param_type) {
 876        case ISCSI_HOST_PARAM:
 877                switch (param) {
 878                case ISCSI_HOST_PARAM_NETDEV_NAME:
 879                case ISCSI_HOST_PARAM_HWADDRESS:
 880                case ISCSI_HOST_PARAM_IPADDRESS:
 881                case ISCSI_HOST_PARAM_INITIATOR_NAME:
 882                        return S_IRUGO;
 883                default:
 884                        return 0;
 885                }
 886        case ISCSI_PARAM:
 887                switch (param) {
 888                case ISCSI_PARAM_MAX_RECV_DLENGTH:
 889                case ISCSI_PARAM_MAX_XMIT_DLENGTH:
 890                case ISCSI_PARAM_HDRDGST_EN:
 891                case ISCSI_PARAM_DATADGST_EN:
 892                case ISCSI_PARAM_CONN_ADDRESS:
 893                case ISCSI_PARAM_CONN_PORT:
 894                case ISCSI_PARAM_EXP_STATSN:
 895                case ISCSI_PARAM_PERSISTENT_ADDRESS:
 896                case ISCSI_PARAM_PERSISTENT_PORT:
 897                case ISCSI_PARAM_PING_TMO:
 898                case ISCSI_PARAM_RECV_TMO:
 899                case ISCSI_PARAM_INITIAL_R2T_EN:
 900                case ISCSI_PARAM_MAX_R2T:
 901                case ISCSI_PARAM_IMM_DATA_EN:
 902                case ISCSI_PARAM_FIRST_BURST:
 903                case ISCSI_PARAM_MAX_BURST:
 904                case ISCSI_PARAM_PDU_INORDER_EN:
 905                case ISCSI_PARAM_DATASEQ_INORDER_EN:
 906                case ISCSI_PARAM_ERL:
 907                case ISCSI_PARAM_TARGET_NAME:
 908                case ISCSI_PARAM_TPGT:
 909                case ISCSI_PARAM_USERNAME:
 910                case ISCSI_PARAM_PASSWORD:
 911                case ISCSI_PARAM_USERNAME_IN:
 912                case ISCSI_PARAM_PASSWORD_IN:
 913                case ISCSI_PARAM_FAST_ABORT:
 914                case ISCSI_PARAM_ABORT_TMO:
 915                case ISCSI_PARAM_LU_RESET_TMO:
 916                case ISCSI_PARAM_TGT_RESET_TMO:
 917                case ISCSI_PARAM_IFACE_NAME:
 918                case ISCSI_PARAM_INITIATOR_NAME:
 919                        return S_IRUGO;
 920                default:
 921                        return 0;
 922                }
 923        }
 924
 925        return 0;
 926}
 927
 928static int iscsi_sw_tcp_slave_alloc(struct scsi_device *sdev)
 929{
 930        set_bit(QUEUE_FLAG_BIDI, &sdev->request_queue->queue_flags);
 931        return 0;
 932}
 933
 934static int iscsi_sw_tcp_slave_configure(struct scsi_device *sdev)
 935{
 936        blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_ANY);
 937        blk_queue_dma_alignment(sdev->request_queue, 0);
 938        return 0;
 939}
 940
 941static struct scsi_host_template iscsi_sw_tcp_sht = {
 942        .module                 = THIS_MODULE,
 943        .name                   = "iSCSI Initiator over TCP/IP",
 944        .queuecommand           = iscsi_queuecommand,
 945        .change_queue_depth     = iscsi_change_queue_depth,
 946        .can_queue              = ISCSI_DEF_XMIT_CMDS_MAX - 1,
 947        .sg_tablesize           = 4096,
 948        .max_sectors            = 0xFFFF,
 949        .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
 950        .eh_abort_handler       = iscsi_eh_abort,
 951        .eh_device_reset_handler= iscsi_eh_device_reset,
 952        .eh_target_reset_handler = iscsi_eh_recover_target,
 953        .use_clustering         = DISABLE_CLUSTERING,
 954        .slave_alloc            = iscsi_sw_tcp_slave_alloc,
 955        .slave_configure        = iscsi_sw_tcp_slave_configure,
 956        .target_alloc           = iscsi_target_alloc,
 957        .proc_name              = "iscsi_tcp",
 958        .this_id                = -1,
 959};
 960
 961static struct iscsi_transport iscsi_sw_tcp_transport = {
 962        .owner                  = THIS_MODULE,
 963        .name                   = "tcp",
 964        .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
 965                                  | CAP_DATADGST,
 966        /* session management */
 967        .create_session         = iscsi_sw_tcp_session_create,
 968        .destroy_session        = iscsi_sw_tcp_session_destroy,
 969        /* connection management */
 970        .create_conn            = iscsi_sw_tcp_conn_create,
 971        .bind_conn              = iscsi_sw_tcp_conn_bind,
 972        .destroy_conn           = iscsi_sw_tcp_conn_destroy,
 973        .attr_is_visible        = iscsi_sw_tcp_attr_is_visible,
 974        .set_param              = iscsi_sw_tcp_conn_set_param,
 975        .get_conn_param         = iscsi_sw_tcp_conn_get_param,
 976        .get_session_param      = iscsi_session_get_param,
 977        .start_conn             = iscsi_conn_start,
 978        .stop_conn              = iscsi_sw_tcp_conn_stop,
 979        /* iscsi host params */
 980        .get_host_param         = iscsi_sw_tcp_host_get_param,
 981        .set_host_param         = iscsi_host_set_param,
 982        /* IO */
 983        .send_pdu               = iscsi_conn_send_pdu,
 984        .get_stats              = iscsi_sw_tcp_conn_get_stats,
 985        /* iscsi task/cmd helpers */
 986        .init_task              = iscsi_tcp_task_init,
 987        .xmit_task              = iscsi_tcp_task_xmit,
 988        .cleanup_task           = iscsi_tcp_cleanup_task,
 989        /* low level pdu helpers */
 990        .xmit_pdu               = iscsi_sw_tcp_pdu_xmit,
 991        .init_pdu               = iscsi_sw_tcp_pdu_init,
 992        .alloc_pdu              = iscsi_sw_tcp_pdu_alloc,
 993        /* recovery */
 994        .session_recovery_timedout = iscsi_session_recovery_timedout,
 995};
 996
 997static int __init iscsi_sw_tcp_init(void)
 998{
 999        if (iscsi_max_lun < 1) {
1000                printk(KERN_ERR "iscsi_tcp: Invalid max_lun value of %u\n",
1001                       iscsi_max_lun);
1002                return -EINVAL;
1003        }
1004
1005        iscsi_sw_tcp_scsi_transport = iscsi_register_transport(
1006                                                &iscsi_sw_tcp_transport);
1007        if (!iscsi_sw_tcp_scsi_transport)
1008                return -ENODEV;
1009
1010        return 0;
1011}
1012
1013static void __exit iscsi_sw_tcp_exit(void)
1014{
1015        iscsi_unregister_transport(&iscsi_sw_tcp_transport);
1016}
1017
1018module_init(iscsi_sw_tcp_init);
1019module_exit(iscsi_sw_tcp_exit);
1020
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