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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * iSCSI Initiator over TCP/IP Data-Path
0004  *
0005  * Copyright (C) 2004 Dmitry Yusupov
0006  * Copyright (C) 2004 Alex Aizman
0007  * Copyright (C) 2005 - 2006 Mike Christie
0008  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
0009  * maintained by open-iscsi@googlegroups.com
0010  *
0011  * See the file COPYING included with this distribution for more details.
0012  *
0013  * Credits:
0014  *  Christoph Hellwig
0015  *  FUJITA Tomonori
0016  *  Arne Redlich
0017  *  Zhenyu Wang
0018  */
0019 
0020 #include <crypto/hash.h>
0021 #include <linux/types.h>
0022 #include <linux/inet.h>
0023 #include <linux/slab.h>
0024 #include <linux/sched/mm.h>
0025 #include <linux/file.h>
0026 #include <linux/blkdev.h>
0027 #include <linux/delay.h>
0028 #include <linux/kfifo.h>
0029 #include <linux/scatterlist.h>
0030 #include <linux/module.h>
0031 #include <linux/backing-dev.h>
0032 #include <net/tcp.h>
0033 #include <scsi/scsi_cmnd.h>
0034 #include <scsi/scsi_device.h>
0035 #include <scsi/scsi_host.h>
0036 #include <scsi/scsi.h>
0037 #include <scsi/scsi_transport_iscsi.h>
0038 #include <trace/events/iscsi.h>
0039 
0040 #include "iscsi_tcp.h"
0041 
0042 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
0043           "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
0044           "Alex Aizman <itn780@yahoo.com>");
0045 MODULE_DESCRIPTION("iSCSI/TCP data-path");
0046 MODULE_LICENSE("GPL");
0047 
0048 static struct scsi_transport_template *iscsi_sw_tcp_scsi_transport;
0049 static struct scsi_host_template iscsi_sw_tcp_sht;
0050 static struct iscsi_transport iscsi_sw_tcp_transport;
0051 
0052 static unsigned int iscsi_max_lun = ~0;
0053 module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
0054 
0055 static bool iscsi_recv_from_iscsi_q;
0056 module_param_named(recv_from_iscsi_q, iscsi_recv_from_iscsi_q, bool, 0644);
0057 MODULE_PARM_DESC(recv_from_iscsi_q, "Set to true to read iSCSI data/headers from the iscsi_q workqueue. The default is false which will perform reads from the network softirq context.");
0058 
0059 static int iscsi_sw_tcp_dbg;
0060 module_param_named(debug_iscsi_tcp, iscsi_sw_tcp_dbg, int,
0061            S_IRUGO | S_IWUSR);
0062 MODULE_PARM_DESC(debug_iscsi_tcp, "Turn on debugging for iscsi_tcp module "
0063          "Set to 1 to turn on, and zero to turn off. Default is off.");
0064 
0065 #define ISCSI_SW_TCP_DBG(_conn, dbg_fmt, arg...)        \
0066     do {                            \
0067         if (iscsi_sw_tcp_dbg)               \
0068             iscsi_conn_printk(KERN_INFO, _conn, \
0069                          "%s " dbg_fmt, \
0070                          __func__, ##arg);  \
0071         iscsi_dbg_trace(trace_iscsi_dbg_sw_tcp,     \
0072                 &(_conn)->cls_conn->dev,    \
0073                 "%s " dbg_fmt, __func__, ##arg);\
0074     } while (0);
0075 
0076 
0077 /**
0078  * iscsi_sw_tcp_recv - TCP receive in sendfile fashion
0079  * @rd_desc: read descriptor
0080  * @skb: socket buffer
0081  * @offset: offset in skb
0082  * @len: skb->len - offset
0083  */
0084 static int iscsi_sw_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
0085                  unsigned int offset, size_t len)
0086 {
0087     struct iscsi_conn *conn = rd_desc->arg.data;
0088     unsigned int consumed, total_consumed = 0;
0089     int status;
0090 
0091     ISCSI_SW_TCP_DBG(conn, "in %d bytes\n", skb->len - offset);
0092 
0093     do {
0094         status = 0;
0095         consumed = iscsi_tcp_recv_skb(conn, skb, offset, 0, &status);
0096         offset += consumed;
0097         total_consumed += consumed;
0098     } while (consumed != 0 && status != ISCSI_TCP_SKB_DONE);
0099 
0100     ISCSI_SW_TCP_DBG(conn, "read %d bytes status %d\n",
0101              skb->len - offset, status);
0102     return total_consumed;
0103 }
0104 
0105 /**
0106  * iscsi_sw_sk_state_check - check socket state
0107  * @sk: socket
0108  *
0109  * If the socket is in CLOSE or CLOSE_WAIT we should
0110  * not close the connection if there is still some
0111  * data pending.
0112  *
0113  * Must be called with sk_callback_lock.
0114  */
0115 static inline int iscsi_sw_sk_state_check(struct sock *sk)
0116 {
0117     struct iscsi_conn *conn = sk->sk_user_data;
0118 
0119     if ((sk->sk_state == TCP_CLOSE_WAIT || sk->sk_state == TCP_CLOSE) &&
0120         (conn->session->state != ISCSI_STATE_LOGGING_OUT) &&
0121         !atomic_read(&sk->sk_rmem_alloc)) {
0122         ISCSI_SW_TCP_DBG(conn, "TCP_CLOSE|TCP_CLOSE_WAIT\n");
0123         iscsi_conn_failure(conn, ISCSI_ERR_TCP_CONN_CLOSE);
0124         return -ECONNRESET;
0125     }
0126     return 0;
0127 }
0128 
0129 static void iscsi_sw_tcp_recv_data(struct iscsi_conn *conn)
0130 {
0131     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0132     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0133     struct sock *sk = tcp_sw_conn->sock->sk;
0134     read_descriptor_t rd_desc;
0135 
0136     /*
0137      * Use rd_desc to pass 'conn' to iscsi_tcp_recv.
0138      * We set count to 1 because we want the network layer to
0139      * hand us all the skbs that are available. iscsi_tcp_recv
0140      * handled pdus that cross buffers or pdus that still need data.
0141      */
0142     rd_desc.arg.data = conn;
0143     rd_desc.count = 1;
0144 
0145     tcp_read_sock(sk, &rd_desc, iscsi_sw_tcp_recv);
0146 
0147     /* If we had to (atomically) map a highmem page,
0148      * unmap it now. */
0149     iscsi_tcp_segment_unmap(&tcp_conn->in.segment);
0150 
0151     iscsi_sw_sk_state_check(sk);
0152 }
0153 
0154 static void iscsi_sw_tcp_recv_data_work(struct work_struct *work)
0155 {
0156     struct iscsi_conn *conn = container_of(work, struct iscsi_conn,
0157                            recvwork);
0158     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0159     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0160     struct sock *sk = tcp_sw_conn->sock->sk;
0161 
0162     lock_sock(sk);
0163     iscsi_sw_tcp_recv_data(conn);
0164     release_sock(sk);
0165 }
0166 
0167 static void iscsi_sw_tcp_data_ready(struct sock *sk)
0168 {
0169     struct iscsi_sw_tcp_conn *tcp_sw_conn;
0170     struct iscsi_tcp_conn *tcp_conn;
0171     struct iscsi_conn *conn;
0172 
0173     read_lock_bh(&sk->sk_callback_lock);
0174     conn = sk->sk_user_data;
0175     if (!conn) {
0176         read_unlock_bh(&sk->sk_callback_lock);
0177         return;
0178     }
0179     tcp_conn = conn->dd_data;
0180     tcp_sw_conn = tcp_conn->dd_data;
0181 
0182     if (tcp_sw_conn->queue_recv)
0183         iscsi_conn_queue_recv(conn);
0184     else
0185         iscsi_sw_tcp_recv_data(conn);
0186     read_unlock_bh(&sk->sk_callback_lock);
0187 }
0188 
0189 static void iscsi_sw_tcp_state_change(struct sock *sk)
0190 {
0191     struct iscsi_tcp_conn *tcp_conn;
0192     struct iscsi_sw_tcp_conn *tcp_sw_conn;
0193     struct iscsi_conn *conn;
0194     void (*old_state_change)(struct sock *);
0195 
0196     read_lock_bh(&sk->sk_callback_lock);
0197     conn = sk->sk_user_data;
0198     if (!conn) {
0199         read_unlock_bh(&sk->sk_callback_lock);
0200         return;
0201     }
0202 
0203     iscsi_sw_sk_state_check(sk);
0204 
0205     tcp_conn = conn->dd_data;
0206     tcp_sw_conn = tcp_conn->dd_data;
0207     old_state_change = tcp_sw_conn->old_state_change;
0208 
0209     read_unlock_bh(&sk->sk_callback_lock);
0210 
0211     old_state_change(sk);
0212 }
0213 
0214 /**
0215  * iscsi_sw_tcp_write_space - Called when more output buffer space is available
0216  * @sk: socket space is available for
0217  **/
0218 static void iscsi_sw_tcp_write_space(struct sock *sk)
0219 {
0220     struct iscsi_conn *conn;
0221     struct iscsi_tcp_conn *tcp_conn;
0222     struct iscsi_sw_tcp_conn *tcp_sw_conn;
0223     void (*old_write_space)(struct sock *);
0224 
0225     read_lock_bh(&sk->sk_callback_lock);
0226     conn = sk->sk_user_data;
0227     if (!conn) {
0228         read_unlock_bh(&sk->sk_callback_lock);
0229         return;
0230     }
0231 
0232     tcp_conn = conn->dd_data;
0233     tcp_sw_conn = tcp_conn->dd_data;
0234     old_write_space = tcp_sw_conn->old_write_space;
0235     read_unlock_bh(&sk->sk_callback_lock);
0236 
0237     old_write_space(sk);
0238 
0239     ISCSI_SW_TCP_DBG(conn, "iscsi_write_space\n");
0240     iscsi_conn_queue_xmit(conn);
0241 }
0242 
0243 static void iscsi_sw_tcp_conn_set_callbacks(struct iscsi_conn *conn)
0244 {
0245     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0246     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0247     struct sock *sk = tcp_sw_conn->sock->sk;
0248 
0249     /* assign new callbacks */
0250     write_lock_bh(&sk->sk_callback_lock);
0251     sk->sk_user_data = conn;
0252     tcp_sw_conn->old_data_ready = sk->sk_data_ready;
0253     tcp_sw_conn->old_state_change = sk->sk_state_change;
0254     tcp_sw_conn->old_write_space = sk->sk_write_space;
0255     sk->sk_data_ready = iscsi_sw_tcp_data_ready;
0256     sk->sk_state_change = iscsi_sw_tcp_state_change;
0257     sk->sk_write_space = iscsi_sw_tcp_write_space;
0258     write_unlock_bh(&sk->sk_callback_lock);
0259 }
0260 
0261 static void
0262 iscsi_sw_tcp_conn_restore_callbacks(struct iscsi_conn *conn)
0263 {
0264     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0265     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0266     struct sock *sk = tcp_sw_conn->sock->sk;
0267 
0268     /* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
0269     write_lock_bh(&sk->sk_callback_lock);
0270     sk->sk_user_data    = NULL;
0271     sk->sk_data_ready   = tcp_sw_conn->old_data_ready;
0272     sk->sk_state_change = tcp_sw_conn->old_state_change;
0273     sk->sk_write_space  = tcp_sw_conn->old_write_space;
0274     sk->sk_no_check_tx = 0;
0275     write_unlock_bh(&sk->sk_callback_lock);
0276 }
0277 
0278 /**
0279  * iscsi_sw_tcp_xmit_segment - transmit segment
0280  * @tcp_conn: the iSCSI TCP connection
0281  * @segment: the buffer to transmnit
0282  *
0283  * This function transmits as much of the buffer as
0284  * the network layer will accept, and returns the number of
0285  * bytes transmitted.
0286  *
0287  * If CRC hashing is enabled, the function will compute the
0288  * hash as it goes. When the entire segment has been transmitted,
0289  * it will retrieve the hash value and send it as well.
0290  */
0291 static int iscsi_sw_tcp_xmit_segment(struct iscsi_tcp_conn *tcp_conn,
0292                      struct iscsi_segment *segment)
0293 {
0294     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0295     struct socket *sk = tcp_sw_conn->sock;
0296     unsigned int copied = 0;
0297     int r = 0;
0298 
0299     while (!iscsi_tcp_segment_done(tcp_conn, segment, 0, r)) {
0300         struct scatterlist *sg;
0301         unsigned int offset, copy;
0302         int flags = 0;
0303 
0304         r = 0;
0305         offset = segment->copied;
0306         copy = segment->size - offset;
0307 
0308         if (segment->total_copied + segment->size < segment->total_size)
0309             flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
0310 
0311         if (tcp_sw_conn->queue_recv)
0312             flags |= MSG_DONTWAIT;
0313 
0314         /* Use sendpage if we can; else fall back to sendmsg */
0315         if (!segment->data) {
0316             sg = segment->sg;
0317             offset += segment->sg_offset + sg->offset;
0318             r = tcp_sw_conn->sendpage(sk, sg_page(sg), offset,
0319                           copy, flags);
0320         } else {
0321             struct msghdr msg = { .msg_flags = flags };
0322             struct kvec iov = {
0323                 .iov_base = segment->data + offset,
0324                 .iov_len = copy
0325             };
0326 
0327             r = kernel_sendmsg(sk, &msg, &iov, 1, copy);
0328         }
0329 
0330         if (r < 0) {
0331             iscsi_tcp_segment_unmap(segment);
0332             return r;
0333         }
0334         copied += r;
0335     }
0336     return copied;
0337 }
0338 
0339 /**
0340  * iscsi_sw_tcp_xmit - TCP transmit
0341  * @conn: iscsi connection
0342  **/
0343 static int iscsi_sw_tcp_xmit(struct iscsi_conn *conn)
0344 {
0345     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0346     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0347     struct iscsi_segment *segment = &tcp_sw_conn->out.segment;
0348     unsigned int consumed = 0;
0349     int rc = 0;
0350 
0351     while (1) {
0352         rc = iscsi_sw_tcp_xmit_segment(tcp_conn, segment);
0353         /*
0354          * We may not have been able to send data because the conn
0355          * is getting stopped. libiscsi will know so propagate err
0356          * for it to do the right thing.
0357          */
0358         if (rc == -EAGAIN)
0359             return rc;
0360         else if (rc < 0) {
0361             rc = ISCSI_ERR_XMIT_FAILED;
0362             goto error;
0363         } else if (rc == 0)
0364             break;
0365 
0366         consumed += rc;
0367 
0368         if (segment->total_copied >= segment->total_size) {
0369             if (segment->done != NULL) {
0370                 rc = segment->done(tcp_conn, segment);
0371                 if (rc != 0)
0372                     goto error;
0373             }
0374         }
0375     }
0376 
0377     ISCSI_SW_TCP_DBG(conn, "xmit %d bytes\n", consumed);
0378 
0379     conn->txdata_octets += consumed;
0380     return consumed;
0381 
0382 error:
0383     /* Transmit error. We could initiate error recovery
0384      * here. */
0385     ISCSI_SW_TCP_DBG(conn, "Error sending PDU, errno=%d\n", rc);
0386     iscsi_conn_failure(conn, rc);
0387     return -EIO;
0388 }
0389 
0390 /**
0391  * iscsi_sw_tcp_xmit_qlen - return the number of bytes queued for xmit
0392  * @conn: iscsi connection
0393  */
0394 static inline int iscsi_sw_tcp_xmit_qlen(struct iscsi_conn *conn)
0395 {
0396     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0397     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0398     struct iscsi_segment *segment = &tcp_sw_conn->out.segment;
0399 
0400     return segment->total_copied - segment->total_size;
0401 }
0402 
0403 static int iscsi_sw_tcp_pdu_xmit(struct iscsi_task *task)
0404 {
0405     struct iscsi_conn *conn = task->conn;
0406     unsigned int noreclaim_flag;
0407     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0408     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0409     int rc = 0;
0410 
0411     if (!tcp_sw_conn->sock) {
0412         iscsi_conn_printk(KERN_ERR, conn,
0413                   "Transport not bound to socket!\n");
0414         return -EINVAL;
0415     }
0416 
0417     noreclaim_flag = memalloc_noreclaim_save();
0418 
0419     while (iscsi_sw_tcp_xmit_qlen(conn)) {
0420         rc = iscsi_sw_tcp_xmit(conn);
0421         if (rc == 0) {
0422             rc = -EAGAIN;
0423             break;
0424         }
0425         if (rc < 0)
0426             break;
0427         rc = 0;
0428     }
0429 
0430     memalloc_noreclaim_restore(noreclaim_flag);
0431     return rc;
0432 }
0433 
0434 /*
0435  * This is called when we're done sending the header.
0436  * Simply copy the data_segment to the send segment, and return.
0437  */
0438 static int iscsi_sw_tcp_send_hdr_done(struct iscsi_tcp_conn *tcp_conn,
0439                       struct iscsi_segment *segment)
0440 {
0441     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0442 
0443     tcp_sw_conn->out.segment = tcp_sw_conn->out.data_segment;
0444     ISCSI_SW_TCP_DBG(tcp_conn->iscsi_conn,
0445              "Header done. Next segment size %u total_size %u\n",
0446              tcp_sw_conn->out.segment.size,
0447              tcp_sw_conn->out.segment.total_size);
0448     return 0;
0449 }
0450 
0451 static void iscsi_sw_tcp_send_hdr_prep(struct iscsi_conn *conn, void *hdr,
0452                        size_t hdrlen)
0453 {
0454     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0455     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0456 
0457     ISCSI_SW_TCP_DBG(conn, "%s\n", conn->hdrdgst_en ?
0458              "digest enabled" : "digest disabled");
0459 
0460     /* Clear the data segment - needs to be filled in by the
0461      * caller using iscsi_tcp_send_data_prep() */
0462     memset(&tcp_sw_conn->out.data_segment, 0,
0463            sizeof(struct iscsi_segment));
0464 
0465     /* If header digest is enabled, compute the CRC and
0466      * place the digest into the same buffer. We make
0467      * sure that both iscsi_tcp_task and mtask have
0468      * sufficient room.
0469      */
0470     if (conn->hdrdgst_en) {
0471         iscsi_tcp_dgst_header(tcp_sw_conn->tx_hash, hdr, hdrlen,
0472                       hdr + hdrlen);
0473         hdrlen += ISCSI_DIGEST_SIZE;
0474     }
0475 
0476     /* Remember header pointer for later, when we need
0477      * to decide whether there's a payload to go along
0478      * with the header. */
0479     tcp_sw_conn->out.hdr = hdr;
0480 
0481     iscsi_segment_init_linear(&tcp_sw_conn->out.segment, hdr, hdrlen,
0482                   iscsi_sw_tcp_send_hdr_done, NULL);
0483 }
0484 
0485 /*
0486  * Prepare the send buffer for the payload data.
0487  * Padding and checksumming will all be taken care
0488  * of by the iscsi_segment routines.
0489  */
0490 static int
0491 iscsi_sw_tcp_send_data_prep(struct iscsi_conn *conn, struct scatterlist *sg,
0492                 unsigned int count, unsigned int offset,
0493                 unsigned int len)
0494 {
0495     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0496     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0497     struct ahash_request *tx_hash = NULL;
0498     unsigned int hdr_spec_len;
0499 
0500     ISCSI_SW_TCP_DBG(conn, "offset=%d, datalen=%d %s\n", offset, len,
0501              conn->datadgst_en ?
0502              "digest enabled" : "digest disabled");
0503 
0504     /* Make sure the datalen matches what the caller
0505        said he would send. */
0506     hdr_spec_len = ntoh24(tcp_sw_conn->out.hdr->dlength);
0507     WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
0508 
0509     if (conn->datadgst_en)
0510         tx_hash = tcp_sw_conn->tx_hash;
0511 
0512     return iscsi_segment_seek_sg(&tcp_sw_conn->out.data_segment,
0513                      sg, count, offset, len,
0514                      NULL, tx_hash);
0515 }
0516 
0517 static void
0518 iscsi_sw_tcp_send_linear_data_prep(struct iscsi_conn *conn, void *data,
0519                    size_t len)
0520 {
0521     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0522     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0523     struct ahash_request *tx_hash = NULL;
0524     unsigned int hdr_spec_len;
0525 
0526     ISCSI_SW_TCP_DBG(conn, "datalen=%zd %s\n", len, conn->datadgst_en ?
0527              "digest enabled" : "digest disabled");
0528 
0529     /* Make sure the datalen matches what the caller
0530        said he would send. */
0531     hdr_spec_len = ntoh24(tcp_sw_conn->out.hdr->dlength);
0532     WARN_ON(iscsi_padded(len) != iscsi_padded(hdr_spec_len));
0533 
0534     if (conn->datadgst_en)
0535         tx_hash = tcp_sw_conn->tx_hash;
0536 
0537     iscsi_segment_init_linear(&tcp_sw_conn->out.data_segment,
0538                 data, len, NULL, tx_hash);
0539 }
0540 
0541 static int iscsi_sw_tcp_pdu_init(struct iscsi_task *task,
0542                  unsigned int offset, unsigned int count)
0543 {
0544     struct iscsi_conn *conn = task->conn;
0545     int err = 0;
0546 
0547     iscsi_sw_tcp_send_hdr_prep(conn, task->hdr, task->hdr_len);
0548 
0549     if (!count)
0550         return 0;
0551 
0552     if (!task->sc)
0553         iscsi_sw_tcp_send_linear_data_prep(conn, task->data, count);
0554     else {
0555         struct scsi_data_buffer *sdb = &task->sc->sdb;
0556 
0557         err = iscsi_sw_tcp_send_data_prep(conn, sdb->table.sgl,
0558                           sdb->table.nents, offset,
0559                           count);
0560     }
0561 
0562     if (err) {
0563         /* got invalid offset/len */
0564         return -EIO;
0565     }
0566     return 0;
0567 }
0568 
0569 static int iscsi_sw_tcp_pdu_alloc(struct iscsi_task *task, uint8_t opcode)
0570 {
0571     struct iscsi_tcp_task *tcp_task = task->dd_data;
0572 
0573     task->hdr = task->dd_data + sizeof(*tcp_task);
0574     task->hdr_max = sizeof(struct iscsi_sw_tcp_hdrbuf) - ISCSI_DIGEST_SIZE;
0575     return 0;
0576 }
0577 
0578 static struct iscsi_cls_conn *
0579 iscsi_sw_tcp_conn_create(struct iscsi_cls_session *cls_session,
0580              uint32_t conn_idx)
0581 {
0582     struct iscsi_conn *conn;
0583     struct iscsi_cls_conn *cls_conn;
0584     struct iscsi_tcp_conn *tcp_conn;
0585     struct iscsi_sw_tcp_conn *tcp_sw_conn;
0586     struct crypto_ahash *tfm;
0587 
0588     cls_conn = iscsi_tcp_conn_setup(cls_session, sizeof(*tcp_sw_conn),
0589                     conn_idx);
0590     if (!cls_conn)
0591         return NULL;
0592     conn = cls_conn->dd_data;
0593     tcp_conn = conn->dd_data;
0594     tcp_sw_conn = tcp_conn->dd_data;
0595     INIT_WORK(&conn->recvwork, iscsi_sw_tcp_recv_data_work);
0596     tcp_sw_conn->queue_recv = iscsi_recv_from_iscsi_q;
0597 
0598     tfm = crypto_alloc_ahash("crc32c", 0, CRYPTO_ALG_ASYNC);
0599     if (IS_ERR(tfm))
0600         goto free_conn;
0601 
0602     tcp_sw_conn->tx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
0603     if (!tcp_sw_conn->tx_hash)
0604         goto free_tfm;
0605     ahash_request_set_callback(tcp_sw_conn->tx_hash, 0, NULL, NULL);
0606 
0607     tcp_sw_conn->rx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
0608     if (!tcp_sw_conn->rx_hash)
0609         goto free_tx_hash;
0610     ahash_request_set_callback(tcp_sw_conn->rx_hash, 0, NULL, NULL);
0611 
0612     tcp_conn->rx_hash = tcp_sw_conn->rx_hash;
0613 
0614     return cls_conn;
0615 
0616 free_tx_hash:
0617     ahash_request_free(tcp_sw_conn->tx_hash);
0618 free_tfm:
0619     crypto_free_ahash(tfm);
0620 free_conn:
0621     iscsi_conn_printk(KERN_ERR, conn,
0622               "Could not create connection due to crc32c "
0623               "loading error. Make sure the crc32c "
0624               "module is built as a module or into the "
0625               "kernel\n");
0626     iscsi_tcp_conn_teardown(cls_conn);
0627     return NULL;
0628 }
0629 
0630 static void iscsi_sw_tcp_release_conn(struct iscsi_conn *conn)
0631 {
0632     struct iscsi_session *session = conn->session;
0633     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0634     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0635     struct socket *sock = tcp_sw_conn->sock;
0636 
0637     if (!sock)
0638         return;
0639 
0640     /*
0641      * Make sure we start socket shutdown now in case userspace is up
0642      * but delayed in releasing the socket.
0643      */
0644     kernel_sock_shutdown(sock, SHUT_RDWR);
0645 
0646     sock_hold(sock->sk);
0647     iscsi_sw_tcp_conn_restore_callbacks(conn);
0648     sock_put(sock->sk);
0649 
0650     iscsi_suspend_rx(conn);
0651 
0652     spin_lock_bh(&session->frwd_lock);
0653     tcp_sw_conn->sock = NULL;
0654     spin_unlock_bh(&session->frwd_lock);
0655     sockfd_put(sock);
0656 }
0657 
0658 static void iscsi_sw_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
0659 {
0660     struct iscsi_conn *conn = cls_conn->dd_data;
0661     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0662     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0663 
0664     iscsi_sw_tcp_release_conn(conn);
0665 
0666     ahash_request_free(tcp_sw_conn->rx_hash);
0667     if (tcp_sw_conn->tx_hash) {
0668         struct crypto_ahash *tfm;
0669 
0670         tfm = crypto_ahash_reqtfm(tcp_sw_conn->tx_hash);
0671         ahash_request_free(tcp_sw_conn->tx_hash);
0672         crypto_free_ahash(tfm);
0673     }
0674 
0675     iscsi_tcp_conn_teardown(cls_conn);
0676 }
0677 
0678 static void iscsi_sw_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
0679 {
0680     struct iscsi_conn *conn = cls_conn->dd_data;
0681     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0682     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0683     struct socket *sock = tcp_sw_conn->sock;
0684 
0685     /* userspace may have goofed up and not bound us */
0686     if (!sock)
0687         return;
0688 
0689     sock->sk->sk_err = EIO;
0690     wake_up_interruptible(sk_sleep(sock->sk));
0691 
0692     /* stop xmit side */
0693     iscsi_suspend_tx(conn);
0694 
0695     /* stop recv side and release socket */
0696     iscsi_sw_tcp_release_conn(conn);
0697 
0698     iscsi_conn_stop(cls_conn, flag);
0699 }
0700 
0701 static int
0702 iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
0703                struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
0704                int is_leading)
0705 {
0706     struct iscsi_session *session = cls_session->dd_data;
0707     struct iscsi_conn *conn = cls_conn->dd_data;
0708     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0709     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0710     struct sock *sk;
0711     struct socket *sock;
0712     int err;
0713 
0714     /* lookup for existing socket */
0715     sock = sockfd_lookup((int)transport_eph, &err);
0716     if (!sock) {
0717         iscsi_conn_printk(KERN_ERR, conn,
0718                   "sockfd_lookup failed %d\n", err);
0719         return -EEXIST;
0720     }
0721 
0722     err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
0723     if (err)
0724         goto free_socket;
0725 
0726     spin_lock_bh(&session->frwd_lock);
0727     /* bind iSCSI connection and socket */
0728     tcp_sw_conn->sock = sock;
0729     spin_unlock_bh(&session->frwd_lock);
0730 
0731     /* setup Socket parameters */
0732     sk = sock->sk;
0733     sk->sk_reuse = SK_CAN_REUSE;
0734     sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
0735     sk->sk_allocation = GFP_ATOMIC;
0736     sk_set_memalloc(sk);
0737     sock_no_linger(sk);
0738 
0739     iscsi_sw_tcp_conn_set_callbacks(conn);
0740     tcp_sw_conn->sendpage = tcp_sw_conn->sock->ops->sendpage;
0741     /*
0742      * set receive state machine into initial state
0743      */
0744     iscsi_tcp_hdr_recv_prep(tcp_conn);
0745     return 0;
0746 
0747 free_socket:
0748     sockfd_put(sock);
0749     return err;
0750 }
0751 
0752 static int iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn *cls_conn,
0753                        enum iscsi_param param, char *buf,
0754                        int buflen)
0755 {
0756     struct iscsi_conn *conn = cls_conn->dd_data;
0757     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0758     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0759 
0760     switch(param) {
0761     case ISCSI_PARAM_HDRDGST_EN:
0762         iscsi_set_param(cls_conn, param, buf, buflen);
0763         break;
0764     case ISCSI_PARAM_DATADGST_EN:
0765         iscsi_set_param(cls_conn, param, buf, buflen);
0766         tcp_sw_conn->sendpage = conn->datadgst_en ?
0767             sock_no_sendpage : tcp_sw_conn->sock->ops->sendpage;
0768         break;
0769     case ISCSI_PARAM_MAX_R2T:
0770         return iscsi_tcp_set_max_r2t(conn, buf);
0771     default:
0772         return iscsi_set_param(cls_conn, param, buf, buflen);
0773     }
0774 
0775     return 0;
0776 }
0777 
0778 static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
0779                        enum iscsi_param param, char *buf)
0780 {
0781     struct iscsi_conn *conn = cls_conn->dd_data;
0782     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0783     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0784     struct sockaddr_in6 addr;
0785     struct socket *sock;
0786     int rc;
0787 
0788     switch(param) {
0789     case ISCSI_PARAM_CONN_PORT:
0790     case ISCSI_PARAM_CONN_ADDRESS:
0791     case ISCSI_PARAM_LOCAL_PORT:
0792         spin_lock_bh(&conn->session->frwd_lock);
0793         if (!tcp_sw_conn || !tcp_sw_conn->sock) {
0794             spin_unlock_bh(&conn->session->frwd_lock);
0795             return -ENOTCONN;
0796         }
0797         sock = tcp_sw_conn->sock;
0798         sock_hold(sock->sk);
0799         spin_unlock_bh(&conn->session->frwd_lock);
0800 
0801         if (param == ISCSI_PARAM_LOCAL_PORT)
0802             rc = kernel_getsockname(sock,
0803                         (struct sockaddr *)&addr);
0804         else
0805             rc = kernel_getpeername(sock,
0806                         (struct sockaddr *)&addr);
0807         sock_put(sock->sk);
0808         if (rc < 0)
0809             return rc;
0810 
0811         return iscsi_conn_get_addr_param((struct sockaddr_storage *)
0812                          &addr, param, buf);
0813     default:
0814         return iscsi_conn_get_param(cls_conn, param, buf);
0815     }
0816 
0817     return 0;
0818 }
0819 
0820 static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
0821                        enum iscsi_host_param param, char *buf)
0822 {
0823     struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(shost);
0824     struct iscsi_session *session = tcp_sw_host->session;
0825     struct iscsi_conn *conn;
0826     struct iscsi_tcp_conn *tcp_conn;
0827     struct iscsi_sw_tcp_conn *tcp_sw_conn;
0828     struct sockaddr_in6 addr;
0829     struct socket *sock;
0830     int rc;
0831 
0832     switch (param) {
0833     case ISCSI_HOST_PARAM_IPADDRESS:
0834         if (!session)
0835             return -ENOTCONN;
0836 
0837         spin_lock_bh(&session->frwd_lock);
0838         conn = session->leadconn;
0839         if (!conn) {
0840             spin_unlock_bh(&session->frwd_lock);
0841             return -ENOTCONN;
0842         }
0843         tcp_conn = conn->dd_data;
0844         tcp_sw_conn = tcp_conn->dd_data;
0845         sock = tcp_sw_conn->sock;
0846         if (!sock) {
0847             spin_unlock_bh(&session->frwd_lock);
0848             return -ENOTCONN;
0849         }
0850         sock_hold(sock->sk);
0851         spin_unlock_bh(&session->frwd_lock);
0852 
0853         rc = kernel_getsockname(sock,
0854                     (struct sockaddr *)&addr);
0855         sock_put(sock->sk);
0856         if (rc < 0)
0857             return rc;
0858 
0859         return iscsi_conn_get_addr_param((struct sockaddr_storage *)
0860                          &addr,
0861                          (enum iscsi_param)param, buf);
0862     default:
0863         return iscsi_host_get_param(shost, param, buf);
0864     }
0865 
0866     return 0;
0867 }
0868 
0869 static void
0870 iscsi_sw_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
0871                 struct iscsi_stats *stats)
0872 {
0873     struct iscsi_conn *conn = cls_conn->dd_data;
0874     struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
0875     struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;
0876 
0877     stats->custom_length = 3;
0878     strcpy(stats->custom[0].desc, "tx_sendpage_failures");
0879     stats->custom[0].value = tcp_sw_conn->sendpage_failures_cnt;
0880     strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
0881     stats->custom[1].value = tcp_sw_conn->discontiguous_hdr_cnt;
0882     strcpy(stats->custom[2].desc, "eh_abort_cnt");
0883     stats->custom[2].value = conn->eh_abort_cnt;
0884 
0885     iscsi_tcp_conn_get_stats(cls_conn, stats);
0886 }
0887 
0888 static struct iscsi_cls_session *
0889 iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
0890                 uint16_t qdepth, uint32_t initial_cmdsn)
0891 {
0892     struct iscsi_cls_session *cls_session;
0893     struct iscsi_session *session;
0894     struct iscsi_sw_tcp_host *tcp_sw_host;
0895     struct Scsi_Host *shost;
0896     int rc;
0897 
0898     if (ep) {
0899         printk(KERN_ERR "iscsi_tcp: invalid ep %p.\n", ep);
0900         return NULL;
0901     }
0902 
0903     shost = iscsi_host_alloc(&iscsi_sw_tcp_sht,
0904                  sizeof(struct iscsi_sw_tcp_host), 1);
0905     if (!shost)
0906         return NULL;
0907     shost->transportt = iscsi_sw_tcp_scsi_transport;
0908     shost->cmd_per_lun = qdepth;
0909     shost->max_lun = iscsi_max_lun;
0910     shost->max_id = 0;
0911     shost->max_channel = 0;
0912     shost->max_cmd_len = SCSI_MAX_VARLEN_CDB_SIZE;
0913 
0914     rc = iscsi_host_get_max_scsi_cmds(shost, cmds_max);
0915     if (rc < 0)
0916         goto free_host;
0917     shost->can_queue = rc;
0918 
0919     if (iscsi_host_add(shost, NULL))
0920         goto free_host;
0921 
0922     cls_session = iscsi_session_setup(&iscsi_sw_tcp_transport, shost,
0923                       cmds_max, 0,
0924                       sizeof(struct iscsi_tcp_task) +
0925                       sizeof(struct iscsi_sw_tcp_hdrbuf),
0926                       initial_cmdsn, 0);
0927     if (!cls_session)
0928         goto remove_host;
0929     session = cls_session->dd_data;
0930     tcp_sw_host = iscsi_host_priv(shost);
0931     tcp_sw_host->session = session;
0932 
0933     if (iscsi_tcp_r2tpool_alloc(session))
0934         goto remove_session;
0935     return cls_session;
0936 
0937 remove_session:
0938     iscsi_session_teardown(cls_session);
0939 remove_host:
0940     iscsi_host_remove(shost, false);
0941 free_host:
0942     iscsi_host_free(shost);
0943     return NULL;
0944 }
0945 
0946 static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
0947 {
0948     struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
0949     struct iscsi_session *session = cls_session->dd_data;
0950 
0951     if (WARN_ON_ONCE(session->leadconn))
0952         return;
0953 
0954     iscsi_tcp_r2tpool_free(cls_session->dd_data);
0955     iscsi_session_teardown(cls_session);
0956 
0957     iscsi_host_remove(shost, false);
0958     iscsi_host_free(shost);
0959 }
0960 
0961 static umode_t iscsi_sw_tcp_attr_is_visible(int param_type, int param)
0962 {
0963     switch (param_type) {
0964     case ISCSI_HOST_PARAM:
0965         switch (param) {
0966         case ISCSI_HOST_PARAM_NETDEV_NAME:
0967         case ISCSI_HOST_PARAM_HWADDRESS:
0968         case ISCSI_HOST_PARAM_IPADDRESS:
0969         case ISCSI_HOST_PARAM_INITIATOR_NAME:
0970             return S_IRUGO;
0971         default:
0972             return 0;
0973         }
0974     case ISCSI_PARAM:
0975         switch (param) {
0976         case ISCSI_PARAM_MAX_RECV_DLENGTH:
0977         case ISCSI_PARAM_MAX_XMIT_DLENGTH:
0978         case ISCSI_PARAM_HDRDGST_EN:
0979         case ISCSI_PARAM_DATADGST_EN:
0980         case ISCSI_PARAM_CONN_ADDRESS:
0981         case ISCSI_PARAM_CONN_PORT:
0982         case ISCSI_PARAM_LOCAL_PORT:
0983         case ISCSI_PARAM_EXP_STATSN:
0984         case ISCSI_PARAM_PERSISTENT_ADDRESS:
0985         case ISCSI_PARAM_PERSISTENT_PORT:
0986         case ISCSI_PARAM_PING_TMO:
0987         case ISCSI_PARAM_RECV_TMO:
0988         case ISCSI_PARAM_INITIAL_R2T_EN:
0989         case ISCSI_PARAM_MAX_R2T:
0990         case ISCSI_PARAM_IMM_DATA_EN:
0991         case ISCSI_PARAM_FIRST_BURST:
0992         case ISCSI_PARAM_MAX_BURST:
0993         case ISCSI_PARAM_PDU_INORDER_EN:
0994         case ISCSI_PARAM_DATASEQ_INORDER_EN:
0995         case ISCSI_PARAM_ERL:
0996         case ISCSI_PARAM_TARGET_NAME:
0997         case ISCSI_PARAM_TPGT:
0998         case ISCSI_PARAM_USERNAME:
0999         case ISCSI_PARAM_PASSWORD:
1000         case ISCSI_PARAM_USERNAME_IN:
1001         case ISCSI_PARAM_PASSWORD_IN:
1002         case ISCSI_PARAM_FAST_ABORT:
1003         case ISCSI_PARAM_ABORT_TMO:
1004         case ISCSI_PARAM_LU_RESET_TMO:
1005         case ISCSI_PARAM_TGT_RESET_TMO:
1006         case ISCSI_PARAM_IFACE_NAME:
1007         case ISCSI_PARAM_INITIATOR_NAME:
1008             return S_IRUGO;
1009         default:
1010             return 0;
1011         }
1012     }
1013 
1014     return 0;
1015 }
1016 
1017 static int iscsi_sw_tcp_slave_configure(struct scsi_device *sdev)
1018 {
1019     struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(sdev->host);
1020     struct iscsi_session *session = tcp_sw_host->session;
1021     struct iscsi_conn *conn = session->leadconn;
1022 
1023     if (conn->datadgst_en)
1024         blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
1025                    sdev->request_queue);
1026     blk_queue_dma_alignment(sdev->request_queue, 0);
1027     return 0;
1028 }
1029 
1030 static struct scsi_host_template iscsi_sw_tcp_sht = {
1031     .module         = THIS_MODULE,
1032     .name           = "iSCSI Initiator over TCP/IP",
1033     .queuecommand           = iscsi_queuecommand,
1034     .change_queue_depth = scsi_change_queue_depth,
1035     .can_queue      = ISCSI_TOTAL_CMDS_MAX,
1036     .sg_tablesize       = 4096,
1037     .max_sectors        = 0xFFFF,
1038     .cmd_per_lun        = ISCSI_DEF_CMD_PER_LUN,
1039     .eh_timed_out       = iscsi_eh_cmd_timed_out,
1040     .eh_abort_handler       = iscsi_eh_abort,
1041     .eh_device_reset_handler= iscsi_eh_device_reset,
1042     .eh_target_reset_handler = iscsi_eh_recover_target,
1043     .dma_boundary       = PAGE_SIZE - 1,
1044     .slave_configure        = iscsi_sw_tcp_slave_configure,
1045     .proc_name      = "iscsi_tcp",
1046     .this_id        = -1,
1047     .track_queue_depth  = 1,
1048     .cmd_size       = sizeof(struct iscsi_cmd),
1049 };
1050 
1051 static struct iscsi_transport iscsi_sw_tcp_transport = {
1052     .owner          = THIS_MODULE,
1053     .name           = "tcp",
1054     .caps           = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
1055                   | CAP_DATADGST,
1056     /* session management */
1057     .create_session     = iscsi_sw_tcp_session_create,
1058     .destroy_session    = iscsi_sw_tcp_session_destroy,
1059     /* connection management */
1060     .create_conn        = iscsi_sw_tcp_conn_create,
1061     .bind_conn      = iscsi_sw_tcp_conn_bind,
1062     .destroy_conn       = iscsi_sw_tcp_conn_destroy,
1063     .attr_is_visible    = iscsi_sw_tcp_attr_is_visible,
1064     .set_param      = iscsi_sw_tcp_conn_set_param,
1065     .get_conn_param     = iscsi_sw_tcp_conn_get_param,
1066     .get_session_param  = iscsi_session_get_param,
1067     .start_conn     = iscsi_conn_start,
1068     .stop_conn      = iscsi_sw_tcp_conn_stop,
1069     /* iscsi host params */
1070     .get_host_param     = iscsi_sw_tcp_host_get_param,
1071     .set_host_param     = iscsi_host_set_param,
1072     /* IO */
1073     .send_pdu       = iscsi_conn_send_pdu,
1074     .get_stats      = iscsi_sw_tcp_conn_get_stats,
1075     /* iscsi task/cmd helpers */
1076     .init_task      = iscsi_tcp_task_init,
1077     .xmit_task      = iscsi_tcp_task_xmit,
1078     .cleanup_task       = iscsi_tcp_cleanup_task,
1079     /* low level pdu helpers */
1080     .xmit_pdu       = iscsi_sw_tcp_pdu_xmit,
1081     .init_pdu       = iscsi_sw_tcp_pdu_init,
1082     .alloc_pdu      = iscsi_sw_tcp_pdu_alloc,
1083     /* recovery */
1084     .session_recovery_timedout = iscsi_session_recovery_timedout,
1085 };
1086 
1087 static int __init iscsi_sw_tcp_init(void)
1088 {
1089     if (iscsi_max_lun < 1) {
1090         printk(KERN_ERR "iscsi_tcp: Invalid max_lun value of %u\n",
1091                iscsi_max_lun);
1092         return -EINVAL;
1093     }
1094 
1095     iscsi_sw_tcp_scsi_transport = iscsi_register_transport(
1096                         &iscsi_sw_tcp_transport);
1097     if (!iscsi_sw_tcp_scsi_transport)
1098         return -ENODEV;
1099 
1100     return 0;
1101 }
1102 
1103 static void __exit iscsi_sw_tcp_exit(void)
1104 {
1105     iscsi_unregister_transport(&iscsi_sw_tcp_transport);
1106 }
1107 
1108 module_init(iscsi_sw_tcp_init);
1109 module_exit(iscsi_sw_tcp_exit);
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