SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/scsi/libiscsi_tcp.c

   1 /*
   2  * iSCSI over TCP/IP Data-Path lib
   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/list.h>
  31 #include <linux/inet.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 <net/tcp.h>
  39 #include <scsi/scsi_cmnd.h>
  40 #include <scsi/scsi_device.h>
  41 #include <scsi/scsi_host.h>
  42 #include <scsi/scsi.h>
  43 #include <scsi/scsi_transport_iscsi.h>
  44
  45 #include "iscsi_tcp.h"
  46
  47 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
  48               "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
  49               "Alex Aizman <itn780@yahoo.com>");
  50 MODULE_DESCRIPTION("iSCSI/TCP data-path");
  51 MODULE_LICENSE("GPL");
  52 #undef DEBUG_TCP
  53
  54 #ifdef DEBUG_TCP
  55 #define debug_tcp(fmt...) printk(KERN_INFO "tcp: " fmt)
  56 #else
  57 #define debug_tcp(fmt...)
  58 #endif
  59
  60 static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
  61                                    struct iscsi_segment *segment);
  62
  63 /*
  64  * Scatterlist handling: inside the iscsi_segment, we
  65  * remember an index into the scatterlist, and set data/size
  66  * to the current scatterlist entry. For highmem pages, we
  67  * kmap as needed.
  68  *
  69  * Note that the page is unmapped when we return from
  70  * TCP's data_ready handler, so we may end up mapping and
  71  * unmapping the same page repeatedly. The whole reason
  72  * for this is that we shouldn't keep the page mapped
  73  * outside the softirq.
  74  */
  75
  76 /**
  77  * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
  78  * @segment: the buffer object
  79  * @sg: scatterlist
  80  * @offset: byte offset into that sg entry
  81  *
  82  * This function sets up the segment so that subsequent
  83  * data is copied to the indicated sg entry, at the given
  84  * offset.
  85  */
  86 static inline void
  87 iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
  88                           struct scatterlist *sg, unsigned int offset)
  89 {
  90         segment->sg = sg;
  91         segment->sg_offset = offset;
  92         segment->size = min(sg->length - offset,
  93                             segment->total_size - segment->total_copied);
  94         segment->data = NULL;
  95 }
  96
  97 /**
  98  * iscsi_tcp_segment_map - map the current S/G page
  99  * @segment: iscsi_segment
 100  * @recv: 1 if called from recv path
 101  *
 102  * We only need to possibly kmap data if scatter lists are being used,
 103  * because the iscsi passthrough and internal IO paths will never use high
 104  * mem pages.
 105  */
 106 static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
 107 {
 108         struct scatterlist *sg;
 109
 110         if (segment->data != NULL || !segment->sg)
 111                 return;
 112
 113         sg = segment->sg;
 114         BUG_ON(segment->sg_mapped);
 115         BUG_ON(sg->length == 0);
 116
 117         /*
 118          * If the page count is greater than one it is ok to send
 119          * to the network layer's zero copy send path. If not we
 120          * have to go the slow sendmsg path. We always map for the
 121          * recv path.
 122          */
 123         if (page_count(sg_page(sg)) >= 1 && !recv)
 124                 return;
 125
 126         debug_tcp("iscsi_tcp_segment_map %s %p\n", recv ? "recv" : "xmit",
 127                   segment);
 128         segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
 129         segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
 130 }
 131
 132 void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
 133 {
 134         debug_tcp("iscsi_tcp_segment_unmap %p\n", segment);
 135
 136         if (segment->sg_mapped) {
 137                 debug_tcp("iscsi_tcp_segment_unmap valid\n");
 138                 kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
 139                 segment->sg_mapped = NULL;
 140                 segment->data = NULL;
 141         }
 142 }
 143 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
 144
 145 /*
 146  * Splice the digest buffer into the buffer
 147  */
 148 static inline void
 149 iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
 150 {
 151         segment->data = digest;
 152         segment->digest_len = ISCSI_DIGEST_SIZE;
 153         segment->total_size += ISCSI_DIGEST_SIZE;
 154         segment->size = ISCSI_DIGEST_SIZE;
 155         segment->copied = 0;
 156         segment->sg = NULL;
 157         segment->hash = NULL;
 158 }
 159
 160 /**
 161  * iscsi_tcp_segment_done - check whether the segment is complete
 162  * @segment: iscsi segment to check
 163  * @recv: set to one of this is called from the recv path
 164  * @copied: number of bytes copied
 165  *
 166  * Check if we're done receiving this segment. If the receive
 167  * buffer is full but we expect more data, move on to the
 168  * next entry in the scatterlist.
 169  *
 170  * If the amount of data we received isn't a multiple of 4,
 171  * we will transparently receive the pad bytes, too.
 172  *
 173  * This function must be re-entrant.
 174  */
 175 int iscsi_tcp_segment_done(struct iscsi_segment *segment, int recv,
 176                            unsigned copied)
 177 {
 178         static unsigned char padbuf[ISCSI_PAD_LEN];
 179         struct scatterlist sg;
 180         unsigned int pad;
 181
 182         debug_tcp("copied %u %u size %u %s\n", segment->copied, copied,
 183                   segment->size, recv ? "recv" : "xmit");
 184         if (segment->hash && copied) {
 185                 /*
 186                  * If a segment is kmapd we must unmap it before sending
 187                  * to the crypto layer since that will try to kmap it again.
 188                  */
 189                 iscsi_tcp_segment_unmap(segment);
 190
 191                 if (!segment->data) {
 192                         sg_init_table(&sg, 1);
 193                         sg_set_page(&sg, sg_page(segment->sg), copied,
 194                                     segment->copied + segment->sg_offset +
 195                                                         segment->sg->offset);
 196                 } else
 197                         sg_init_one(&sg, segment->data + segment->copied,
 198                                     copied);
 199                 crypto_hash_update(segment->hash, &sg, copied);
 200         }
 201
 202         segment->copied += copied;
 203         if (segment->copied < segment->size) {
 204                 iscsi_tcp_segment_map(segment, recv);
 205                 return 0;
 206         }
 207
 208         segment->total_copied += segment->copied;
 209         segment->copied = 0;
 210         segment->size = 0;
 211
 212         /* Unmap the current scatterlist page, if there is one. */
 213         iscsi_tcp_segment_unmap(segment);
 214
 215         /* Do we have more scatterlist entries? */
 216         debug_tcp("total copied %u total size %u\n", segment->total_copied,
 217                    segment->total_size);
 218         if (segment->total_copied < segment->total_size) {
 219                 /* Proceed to the next entry in the scatterlist. */
 220                 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
 221                                           0);
 222                 iscsi_tcp_segment_map(segment, recv);
 223                 BUG_ON(segment->size == 0);
 224                 return 0;
 225         }
 226
 227         /* Do we need to handle padding? */
 228         pad = iscsi_padding(segment->total_copied);
 229         if (pad != 0) {
 230                 debug_tcp("consume %d pad bytes\n", pad);
 231                 segment->total_size += pad;
 232                 segment->size = pad;
 233                 segment->data = padbuf;
 234                 return 0;
 235         }
 236
 237         /*
 238          * Set us up for transferring the data digest. hdr digest
 239          * is completely handled in hdr done function.
 240          */
 241         if (segment->hash) {
 242                 crypto_hash_final(segment->hash, segment->digest);
 243                 iscsi_tcp_segment_splice_digest(segment,
 244                                  recv ? segment->recv_digest : segment->digest);
 245                 return 0;
 246         }
 247
 248         return 1;
 249 }
 250 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
 251
 252 /**
 253  * iscsi_tcp_segment_recv - copy data to segment
 254  * @tcp_conn: the iSCSI TCP connection
 255  * @segment: the buffer to copy to
 256  * @ptr: data pointer
 257  * @len: amount of data available
 258  *
 259  * This function copies up to @len bytes to the
 260  * given buffer, and returns the number of bytes
 261  * consumed, which can actually be less than @len.
 262  *
 263  * If hash digest is enabled, the function will update the
 264  * hash while copying.
 265  * Combining these two operations doesn't buy us a lot (yet),
 266  * but in the future we could implement combined copy+crc,
 267  * just way we do for network layer checksums.
 268  */
 269 static int
 270 iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
 271                        struct iscsi_segment *segment, const void *ptr,
 272                        unsigned int len)
 273 {
 274         unsigned int copy = 0, copied = 0;
 275
 276         while (!iscsi_tcp_segment_done(segment, 1, copy)) {
 277                 if (copied == len) {
 278                         debug_tcp("iscsi_tcp_segment_recv copied %d bytes\n",
 279                                   len);
 280                         break;
 281                 }
 282
 283                 copy = min(len - copied, segment->size - segment->copied);
 284                 debug_tcp("iscsi_tcp_segment_recv copying %d\n", copy);
 285                 memcpy(segment->data + segment->copied, ptr + copied, copy);
 286                 copied += copy;
 287         }
 288         return copied;
 289 }
 290
 291 inline void
 292 iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
 293                       unsigned char digest[ISCSI_DIGEST_SIZE])
 294 {
 295         struct scatterlist sg;
 296
 297         sg_init_one(&sg, hdr, hdrlen);
 298         crypto_hash_digest(hash, &sg, hdrlen, digest);
 299 }
 300 EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
 301
 302 static inline int
 303 iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
 304                       struct iscsi_segment *segment)
 305 {
 306         if (!segment->digest_len)
 307                 return 1;
 308
 309         if (memcmp(segment->recv_digest, segment->digest,
 310                    segment->digest_len)) {
 311                 debug_scsi("digest mismatch\n");
 312                 return 0;
 313         }
 314
 315         return 1;
 316 }
 317
 318 /*
 319  * Helper function to set up segment buffer
 320  */
 321 static inline void
 322 __iscsi_segment_init(struct iscsi_segment *segment, size_t size,
 323                      iscsi_segment_done_fn_t *done, struct hash_desc *hash)
 324 {
 325         memset(segment, 0, sizeof(*segment));
 326         segment->total_size = size;
 327         segment->done = done;
 328
 329         if (hash) {
 330                 segment->hash = hash;
 331                 crypto_hash_init(hash);
 332         }
 333 }
 334
 335 inline void
 336 iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
 337                           size_t size, iscsi_segment_done_fn_t *done,
 338                           struct hash_desc *hash)
 339 {
 340         __iscsi_segment_init(segment, size, done, hash);
 341         segment->data = data;
 342         segment->size = size;
 343 }
 344 EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
 345
 346 inline int
 347 iscsi_segment_seek_sg(struct iscsi_segment *segment,
 348                       struct scatterlist *sg_list, unsigned int sg_count,
 349                       unsigned int offset, size_t size,
 350                       iscsi_segment_done_fn_t *done, struct hash_desc *hash)
 351 {
 352         struct scatterlist *sg;
 353         unsigned int i;
 354
 355         debug_scsi("iscsi_segment_seek_sg offset %u size %llu\n",
 356                   offset, size);
 357         __iscsi_segment_init(segment, size, done, hash);
 358         for_each_sg(sg_list, sg, sg_count, i) {
 359                 debug_scsi("sg %d, len %u offset %u\n", i, sg->length,
 360                            sg->offset);
 361                 if (offset < sg->length) {
 362                         iscsi_tcp_segment_init_sg(segment, sg, offset);
 363                         return 0;
 364                 }
 365                 offset -= sg->length;
 366         }
 367
 368         return ISCSI_ERR_DATA_OFFSET;
 369 }
 370 EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
 371
 372 /**
 373  * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
 374  * @tcp_conn: iscsi connection to prep for
 375  *
 376  * This function always passes NULL for the hash argument, because when this
 377  * function is called we do not yet know the final size of the header and want
 378  * to delay the digest processing until we know that.
 379  */
 380 void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 381 {
 382         debug_tcp("iscsi_tcp_hdr_recv_prep(%p%s)\n", tcp_conn,
 383                   tcp_conn->iscsi_conn->hdrdgst_en ? ", digest enabled" : "");
 384         iscsi_segment_init_linear(&tcp_conn->in.segment,
 385                                 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
 386                                 iscsi_tcp_hdr_recv_done, NULL);
 387 }
 388 EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
 389
 390 /*
 391  * Handle incoming reply to any other type of command
 392  */
 393 static int
 394 iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
 395                          struct iscsi_segment *segment)
 396 {
 397         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 398         int rc = 0;
 399
 400         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 401                 return ISCSI_ERR_DATA_DGST;
 402
 403         rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
 404                         conn->data, tcp_conn->in.datalen);
 405         if (rc)
 406                 return rc;
 407
 408         iscsi_tcp_hdr_recv_prep(tcp_conn);
 409         return 0;
 410 }
 411
 412 static void
 413 iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
 414 {
 415         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 416         struct hash_desc *rx_hash = NULL;
 417
 418         if (conn->datadgst_en &
 419             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 420                 rx_hash = tcp_conn->rx_hash;
 421
 422         iscsi_segment_init_linear(&tcp_conn->in.segment,
 423                                 conn->data, tcp_conn->in.datalen,
 424                                 iscsi_tcp_data_recv_done, rx_hash);
 425 }
 426
 427 /**
 428  * iscsi_tcp_cleanup_task - free tcp_task resources
 429  * @task: iscsi task
 430  *
 431  * must be called with session lock
 432  */
 433 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
 434 {
 435         struct iscsi_tcp_task *tcp_task = task->dd_data;
 436         struct iscsi_r2t_info *r2t;
 437
 438         /* nothing to do for mgmt or pending tasks */
 439         if (!task->sc || task->state == ISCSI_TASK_PENDING)
 440                 return;
 441
 442         /* flush task's r2t queues */
 443         while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
 444                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
 445                             sizeof(void*));
 446                 debug_scsi("iscsi_tcp_cleanup_task pending r2t dropped\n");
 447         }
 448
 449         r2t = tcp_task->r2t;
 450         if (r2t != NULL) {
 451                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
 452                             sizeof(void*));
 453                 tcp_task->r2t = NULL;
 454         }
 455 }
 456 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
 457
 458 /**
 459  * iscsi_tcp_data_in - SCSI Data-In Response processing
 460  * @conn: iscsi connection
 461  * @task: scsi command task
 462  */
 463 static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
 464 {
 465         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 466         struct iscsi_tcp_task *tcp_task = task->dd_data;
 467         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
 468         int datasn = be32_to_cpu(rhdr->datasn);
 469         unsigned total_in_length = scsi_in(task->sc)->length;
 470
 471         iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
 472         if (tcp_conn->in.datalen == 0)
 473                 return 0;
 474
 475         if (tcp_task->exp_datasn != datasn) {
 476                 debug_tcp("%s: task->exp_datasn(%d) != rhdr->datasn(%d)\n",
 477                           __func__, tcp_task->exp_datasn, datasn);
 478                 return ISCSI_ERR_DATASN;
 479         }
 480
 481         tcp_task->exp_datasn++;
 482
 483         tcp_task->data_offset = be32_to_cpu(rhdr->offset);
 484         if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
 485                 debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n",
 486                           __func__, tcp_task->data_offset,
 487                           tcp_conn->in.datalen, total_in_length);
 488                 return ISCSI_ERR_DATA_OFFSET;
 489         }
 490
 491         conn->datain_pdus_cnt++;
 492         return 0;
 493 }
 494
 495 /**
 496  * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
 497  * @conn: iscsi connection
 498  * @task: scsi command task
 499  */
 500 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 501 {
 502         struct iscsi_session *session = conn->session;
 503         struct iscsi_tcp_task *tcp_task = task->dd_data;
 504         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 505         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
 506         struct iscsi_r2t_info *r2t;
 507         int r2tsn = be32_to_cpu(rhdr->r2tsn);
 508         int rc;
 509
 510         if (tcp_conn->in.datalen) {
 511                 iscsi_conn_printk(KERN_ERR, conn,
 512                                   "invalid R2t with datalen %d\n",
 513                                   tcp_conn->in.datalen);
 514                 return ISCSI_ERR_DATALEN;
 515         }
 516
 517         if (tcp_task->exp_datasn != r2tsn){
 518                 debug_tcp("%s: task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
 519                           __func__, tcp_task->exp_datasn, r2tsn);
 520                 return ISCSI_ERR_R2TSN;
 521         }
 522
 523         /* fill-in new R2T associated with the task */
 524         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
 525
 526         if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
 527                 iscsi_conn_printk(KERN_INFO, conn,
 528                                   "dropping R2T itt %d in recovery.\n",
 529                                   task->itt);
 530                 return 0;
 531         }
 532
 533         rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
 534         if (!rc) {
 535                 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
 536                                   "Target has sent more R2Ts than it "
 537                                   "negotiated for or driver has has leaked.\n");
 538                 return ISCSI_ERR_PROTO;
 539         }
 540
 541         r2t->exp_statsn = rhdr->statsn;
 542         r2t->data_length = be32_to_cpu(rhdr->data_length);
 543         if (r2t->data_length == 0) {
 544                 iscsi_conn_printk(KERN_ERR, conn,
 545                                   "invalid R2T with zero data len\n");
 546                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
 547                             sizeof(void*));
 548                 return ISCSI_ERR_DATALEN;
 549         }
 550
 551         if (r2t->data_length > session->max_burst)
 552                 debug_scsi("invalid R2T with data len %u and max burst %u."
 553                            "Attempting to execute request.\n",
 554                             r2t->data_length, session->max_burst);
 555
 556         r2t->data_offset = be32_to_cpu(rhdr->data_offset);
 557         if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
 558                 iscsi_conn_printk(KERN_ERR, conn,
 559                                   "invalid R2T with data len %u at offset %u "
 560                                   "and total length %d\n", r2t->data_length,
 561                                   r2t->data_offset, scsi_out(task->sc)->length);
 562                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
 563                             sizeof(void*));
 564                 return ISCSI_ERR_DATALEN;
 565         }
 566
 567         r2t->ttt = rhdr->ttt; /* no flip */
 568         r2t->datasn = 0;
 569         r2t->sent = 0;
 570
 571         tcp_task->exp_datasn = r2tsn + 1;
 572         __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
 573         conn->r2t_pdus_cnt++;
 574
 575         iscsi_requeue_task(task);
 576         return 0;
 577 }
 578
 579 /*
 580  * Handle incoming reply to DataIn command
 581  */
 582 static int
 583 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
 584                           struct iscsi_segment *segment)
 585 {
 586         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 587         struct iscsi_hdr *hdr = tcp_conn->in.hdr;
 588         int rc;
 589
 590         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 591                 return ISCSI_ERR_DATA_DGST;
 592
 593         /* check for non-exceptional status */
 594         if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
 595                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
 596                 if (rc)
 597                         return rc;
 598         }
 599
 600         iscsi_tcp_hdr_recv_prep(tcp_conn);
 601         return 0;
 602 }
 603
 604 /**
 605  * iscsi_tcp_hdr_dissect - process PDU header
 606  * @conn: iSCSI connection
 607  * @hdr: PDU header
 608  *
 609  * This function analyzes the header of the PDU received,
 610  * and performs several sanity checks. If the PDU is accompanied
 611  * by data, the receive buffer is set up to copy the incoming data
 612  * to the correct location.
 613  */
 614 static int
 615 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 616 {
 617         int rc = 0, opcode, ahslen;
 618         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 619         struct iscsi_task *task;
 620
 621         /* verify PDU length */
 622         tcp_conn->in.datalen = ntoh24(hdr->dlength);
 623         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
 624                 iscsi_conn_printk(KERN_ERR, conn,
 625                                   "iscsi_tcp: datalen %d > %d\n",
 626                                   tcp_conn->in.datalen, conn->max_recv_dlength);
 627                 return ISCSI_ERR_DATALEN;
 628         }
 629
 630         /* Additional header segments. So far, we don't
 631          * process additional headers.
 632          */
 633         ahslen = hdr->hlength << 2;
 634
 635         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 636         /* verify itt (itt encoding: age+cid+itt) */
 637         rc = iscsi_verify_itt(conn, hdr->itt);
 638         if (rc)
 639                 return rc;
 640
 641         debug_tcp("opcode 0x%x ahslen %d datalen %d\n",
 642                   opcode, ahslen, tcp_conn->in.datalen);
 643
 644         switch(opcode) {
 645         case ISCSI_OP_SCSI_DATA_IN:
 646                 spin_lock(&conn->session->lock);
 647                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 648                 if (!task)
 649                         rc = ISCSI_ERR_BAD_ITT;
 650                 else
 651                         rc = iscsi_tcp_data_in(conn, task);
 652                 if (rc) {
 653                         spin_unlock(&conn->session->lock);
 654                         break;
 655                 }
 656
 657                 if (tcp_conn->in.datalen) {
 658                         struct iscsi_tcp_task *tcp_task = task->dd_data;
 659                         struct hash_desc *rx_hash = NULL;
 660                         struct scsi_data_buffer *sdb = scsi_in(task->sc);
 661
 662                         /*
 663                          * Setup copy of Data-In into the Scsi_Cmnd
 664                          * Scatterlist case:
 665                          * We set up the iscsi_segment to point to the next
 666                          * scatterlist entry to copy to. As we go along,
 667                          * we move on to the next scatterlist entry and
 668                          * update the digest per-entry.
 669                          */
 670                         if (conn->datadgst_en &&
 671                             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
 672                                 rx_hash = tcp_conn->rx_hash;
 673
 674                         debug_tcp("iscsi_tcp_begin_data_in(%p, offset=%d, "
 675                                   "datalen=%d)\n", tcp_conn,
 676                                   tcp_task->data_offset,
 677                                   tcp_conn->in.datalen);
 678                         rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
 679                                                    sdb->table.sgl,
 680                                                    sdb->table.nents,
 681                                                    tcp_task->data_offset,
 682                                                    tcp_conn->in.datalen,
 683                                                    iscsi_tcp_process_data_in,
 684                                                    rx_hash);
 685                         spin_unlock(&conn->session->lock);
 686                         return rc;
 687                 }
 688                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
 689                 spin_unlock(&conn->session->lock);
 690                 break;
 691         case ISCSI_OP_SCSI_CMD_RSP:
 692                 if (tcp_conn->in.datalen) {
 693                         iscsi_tcp_data_recv_prep(tcp_conn);
 694                         return 0;
 695                 }
 696                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 697                 break;
 698         case ISCSI_OP_R2T:
 699                 spin_lock(&conn->session->lock);
 700                 task = iscsi_itt_to_ctask(conn, hdr->itt);
 701                 if (!task)
 702                         rc = ISCSI_ERR_BAD_ITT;
 703                 else if (ahslen)
 704                         rc = ISCSI_ERR_AHSLEN;
 705                 else if (task->sc->sc_data_direction == DMA_TO_DEVICE)
 706                         rc = iscsi_tcp_r2t_rsp(conn, task);
 707                 else
 708                         rc = ISCSI_ERR_PROTO;
 709                 spin_unlock(&conn->session->lock);
 710                 break;
 711         case ISCSI_OP_LOGIN_RSP:
 712         case ISCSI_OP_TEXT_RSP:
 713         case ISCSI_OP_REJECT:
 714         case ISCSI_OP_ASYNC_EVENT:
 715                 /*
 716                  * It is possible that we could get a PDU with a buffer larger
 717                  * than 8K, but there are no targets that currently do this.
 718                  * For now we fail until we find a vendor that needs it
 719                  */
 720                 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
 721                         iscsi_conn_printk(KERN_ERR, conn,
 722                                           "iscsi_tcp: received buffer of "
 723                                           "len %u but conn buffer is only %u "
 724                                           "(opcode %0x)\n",
 725                                           tcp_conn->in.datalen,
 726                                           ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
 727                         rc = ISCSI_ERR_PROTO;
 728                         break;
 729                 }
 730
 731                 /* If there's data coming in with the response,
 732                  * receive it to the connection's buffer.
 733                  */
 734                 if (tcp_conn->in.datalen) {
 735                         iscsi_tcp_data_recv_prep(tcp_conn);
 736                         return 0;
 737                 }
 738         /* fall through */
 739         case ISCSI_OP_LOGOUT_RSP:
 740         case ISCSI_OP_NOOP_IN:
 741         case ISCSI_OP_SCSI_TMFUNC_RSP:
 742                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 743                 break;
 744         default:
 745                 rc = ISCSI_ERR_BAD_OPCODE;
 746                 break;
 747         }
 748
 749         if (rc == 0) {
 750                 /* Anything that comes with data should have
 751                  * been handled above. */
 752                 if (tcp_conn->in.datalen)
 753                         return ISCSI_ERR_PROTO;
 754                 iscsi_tcp_hdr_recv_prep(tcp_conn);
 755         }
 756
 757         return rc;
 758 }
 759
 760 /**
 761  * iscsi_tcp_hdr_recv_done - process PDU header
 762  *
 763  * This is the callback invoked when the PDU header has
 764  * been received. If the header is followed by additional
 765  * header segments, we go back for more data.
 766  */
 767 static int
 768 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
 769                         struct iscsi_segment *segment)
 770 {
 771         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
 772         struct iscsi_hdr *hdr;
 773
 774         /* Check if there are additional header segments
 775          * *prior* to computing the digest, because we
 776          * may need to go back to the caller for more.
 777          */
 778         hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
 779         if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
 780                 /* Bump the header length - the caller will
 781                  * just loop around and get the AHS for us, and
 782                  * call again. */
 783                 unsigned int ahslen = hdr->hlength << 2;
 784
 785                 /* Make sure we don't overflow */
 786                 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
 787                         return ISCSI_ERR_AHSLEN;
 788
 789                 segment->total_size += ahslen;
 790                 segment->size += ahslen;
 791                 return 0;
 792         }
 793
 794         /* We're done processing the header. See if we're doing
 795          * header digests; if so, set up the recv_digest buffer
 796          * and go back for more. */
 797         if (conn->hdrdgst_en) {
 798                 if (segment->digest_len == 0) {
 799                         /*
 800                          * Even if we offload the digest processing we
 801                          * splice it in so we can increment the skb/segment
 802                          * counters in preparation for the data segment.
 803                          */
 804                         iscsi_tcp_segment_splice_digest(segment,
 805                                                         segment->recv_digest);
 806                         return 0;
 807                 }
 808
 809                 if (!(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
 810                         iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
 811                                 segment->total_copied - ISCSI_DIGEST_SIZE,
 812                                 segment->digest);
 813
 814                         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
 815                                 return ISCSI_ERR_HDR_DGST;
 816                 }
 817         }
 818
 819         tcp_conn->in.hdr = hdr;
 820         return iscsi_tcp_hdr_dissect(conn, hdr);
 821 }
 822
 823 /**
 824  * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
 825  * @tcp_conn: iscsi tcp conn
 826  *
 827  * returns non zero if we are currently processing or setup to process
 828  * a header.
 829  */
 830 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
 831 {
 832         return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
 833 }
 834 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
 835
 836 /**
 837  * iscsi_tcp_recv_skb - Process skb
 838  * @conn: iscsi connection
 839  * @skb: network buffer with header and/or data segment
 840  * @offset: offset in skb
 841  * @offload: bool indicating if transfer was offloaded
 842  *
 843  * Will return status of transfer in status. And will return
 844  * number of bytes copied.
 845  */
 846 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
 847                        unsigned int offset, bool offloaded, int *status)
 848 {
 849         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
 850         struct iscsi_segment *segment = &tcp_conn->in.segment;
 851         struct skb_seq_state seq;
 852         unsigned int consumed = 0;
 853         int rc = 0;
 854
 855         debug_tcp("in %d bytes\n", skb->len - offset);
 856
 857         if (unlikely(conn->suspend_rx)) {
 858                 debug_tcp("conn %d Rx suspended!\n", conn->id);
 859                 *status = ISCSI_TCP_SUSPENDED;
 860                 return 0;
 861         }
 862
 863         if (offloaded) {
 864                 segment->total_copied = segment->total_size;
 865                 goto segment_done;
 866         }
 867
 868         skb_prepare_seq_read(skb, offset, skb->len, &seq);
 869         while (1) {
 870                 unsigned int avail;
 871                 const u8 *ptr;
 872
 873                 avail = skb_seq_read(consumed, &ptr, &seq);
 874                 if (avail == 0) {
 875                         debug_tcp("no more data avail. Consumed %d\n",
 876                                   consumed);
 877                         *status = ISCSI_TCP_SKB_DONE;
 878                         skb_abort_seq_read(&seq);
 879                         goto skb_done;
 880                 }
 881                 BUG_ON(segment->copied >= segment->size);
 882
 883                 debug_tcp("skb %p ptr=%p avail=%u\n", skb, ptr, avail);
 884                 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
 885                 BUG_ON(rc == 0);
 886                 consumed += rc;
 887
 888                 if (segment->total_copied >= segment->total_size) {
 889                         skb_abort_seq_read(&seq);
 890                         goto segment_done;
 891                 }
 892         }
 893
 894 segment_done:
 895         *status = ISCSI_TCP_SEGMENT_DONE;
 896         debug_tcp("segment done\n");
 897         rc = segment->done(tcp_conn, segment);
 898         if (rc != 0) {
 899                 *status = ISCSI_TCP_CONN_ERR;
 900                 debug_tcp("Error receiving PDU, errno=%d\n", rc);
 901                 iscsi_conn_failure(conn, rc);
 902                 return 0;
 903         }
 904         /* The done() functions sets up the next segment. */
 905
 906 skb_done:
 907         conn->rxdata_octets += consumed;
 908         return consumed;
 909 }
 910 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
 911
 912 /**
 913  * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 914  * @conn: iscsi connection
 915  * @task: scsi command task
 916  * @sc: scsi command
 917  */
 918 int iscsi_tcp_task_init(struct iscsi_task *task)
 919 {
 920         struct iscsi_tcp_task *tcp_task = task->dd_data;
 921         struct iscsi_conn *conn = task->conn;
 922         struct scsi_cmnd *sc = task->sc;
 923         int err;
 924
 925         if (!sc) {
 926                 /*
 927                  * mgmt tasks do not have a scatterlist since they come
 928                  * in from the iscsi interface.
 929                  */
 930                 debug_scsi("mtask deq [cid %d itt 0x%x]\n", conn->id,
 931                            task->itt);
 932
 933                 return conn->session->tt->init_pdu(task, 0, task->data_count);
 934         }
 935
 936         BUG_ON(__kfifo_len(tcp_task->r2tqueue));
 937         tcp_task->exp_datasn = 0;
 938
 939         /* Prepare PDU, optionally w/ immediate data */
 940         debug_scsi("task deq [cid %d itt 0x%x imm %d unsol %d]\n",
 941                     conn->id, task->itt, task->imm_count,
 942                     task->unsol_r2t.data_length);
 943
 944         err = conn->session->tt->init_pdu(task, 0, task->imm_count);
 945         if (err)
 946                 return err;
 947         task->imm_count = 0;
 948         return 0;
 949 }
 950 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
 951
 952 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
 953 {
 954         struct iscsi_session *session = task->conn->session;
 955         struct iscsi_tcp_task *tcp_task = task->dd_data;
 956         struct iscsi_r2t_info *r2t = NULL;
 957
 958         if (iscsi_task_has_unsol_data(task))
 959                 r2t = &task->unsol_r2t;
 960         else {
 961                 spin_lock_bh(&session->lock);
 962                 if (tcp_task->r2t) {
 963                         r2t = tcp_task->r2t;
 964                         /* Continue with this R2T? */
 965                         if (r2t->data_length <= r2t->sent) {
 966                                 debug_scsi("  done with r2t %p\n", r2t);
 967                                 __kfifo_put(tcp_task->r2tpool.queue,
 968                                             (void *)&tcp_task->r2t,
 969                                             sizeof(void *));
 970                                 tcp_task->r2t = r2t = NULL;
 971                         }
 972                 }
 973
 974                 if (r2t == NULL) {
 975                         __kfifo_get(tcp_task->r2tqueue,
 976                                     (void *)&tcp_task->r2t, sizeof(void *));
 977                         r2t = tcp_task->r2t;
 978                 }
 979                 spin_unlock_bh(&session->lock);
 980         }
 981
 982         return r2t;
 983 }
 984
 985 /**
 986  * iscsi_tcp_task_xmit - xmit normal PDU task
 987  * @task: iscsi command task
 988  *
 989  * We're expected to return 0 when everything was transmitted succesfully,
 990  * -EAGAIN if there's still data in the queue, or != 0 for any other kind
 991  * of error.
 992  */
 993 int iscsi_tcp_task_xmit(struct iscsi_task *task)
 994 {
 995         struct iscsi_conn *conn = task->conn;
 996         struct iscsi_session *session = conn->session;
 997         struct iscsi_r2t_info *r2t;
 998         int rc = 0;
 999
1000 flush:
1001         /* Flush any pending data first. */
1002         rc = session->tt->xmit_pdu(task);
1003         if (rc < 0)
1004                 return rc;
1005
1006         /* mgmt command */
1007         if (!task->sc) {
1008                 if (task->hdr->itt == RESERVED_ITT)
1009                         iscsi_put_task(task);
1010                 return 0;
1011         }
1012
1013         /* Are we done already? */
1014         if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1015                 return 0;
1016
1017         r2t = iscsi_tcp_get_curr_r2t(task);
1018         if (r2t == NULL) {
1019                 /* Waiting for more R2Ts to arrive. */
1020                 debug_tcp("no R2Ts yet\n");
1021                 return 0;
1022         }
1023
1024         rc = conn->session->tt->alloc_pdu(task);
1025         if (rc)
1026                 return rc;
1027         iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1028
1029         debug_scsi("sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1030                    r2t, r2t->datasn - 1, task->hdr->itt,
1031                    r2t->data_offset + r2t->sent, r2t->data_count);
1032
1033         rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1034                                          r2t->data_count);
1035         if (rc)
1036                 return rc;
1037         r2t->sent += r2t->data_count;
1038         goto flush;
1039 }
1040 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1041
1042 struct iscsi_cls_conn *
1043 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1044                       uint32_t conn_idx)
1045
1046 {
1047         struct iscsi_conn *conn;
1048         struct iscsi_cls_conn *cls_conn;
1049         struct iscsi_tcp_conn *tcp_conn;
1050
1051         cls_conn = iscsi_conn_setup(cls_session, sizeof(*tcp_conn), conn_idx);
1052         if (!cls_conn)
1053                 return NULL;
1054         conn = cls_conn->dd_data;
1055         /*
1056          * due to strange issues with iser these are not set
1057          * in iscsi_conn_setup
1058          */
1059         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1060
1061         tcp_conn = conn->dd_data;
1062         tcp_conn->iscsi_conn = conn;
1063
1064         tcp_conn->dd_data = kzalloc(dd_data_size, GFP_KERNEL);
1065         if (!tcp_conn->dd_data) {
1066                 iscsi_conn_teardown(cls_conn);
1067                 return NULL;
1068         }
1069         return cls_conn;
1070 }
1071 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1072
1073 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1074 {
1075         struct iscsi_conn *conn = cls_conn->dd_data;
1076         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1077
1078         kfree(tcp_conn->dd_data);
1079         iscsi_conn_teardown(cls_conn);
1080 }
1081 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1082
1083 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1084 {
1085         int i;
1086         int cmd_i;
1087
1088         /*
1089          * initialize per-task: R2T pool and xmit queue
1090          */
1091         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1092                 struct iscsi_task *task = session->cmds[cmd_i];
1093                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1094
1095                 /*
1096                  * pre-allocated x2 as much r2ts to handle race when
1097                  * target acks DataOut faster than we data_xmit() queues
1098                  * could replenish r2tqueue.
1099                  */
1100
1101                 /* R2T pool */
1102                 if (iscsi_pool_init(&tcp_task->r2tpool,
1103                                     session->max_r2t * 2, NULL,
1104                                     sizeof(struct iscsi_r2t_info))) {
1105                         goto r2t_alloc_fail;
1106                 }
1107
1108                 /* R2T xmit queue */
1109                 tcp_task->r2tqueue = kfifo_alloc(
1110                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
1111                 if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) {
1112                         iscsi_pool_free(&tcp_task->r2tpool);
1113                         goto r2t_alloc_fail;
1114                 }
1115         }
1116
1117         return 0;
1118
1119 r2t_alloc_fail:
1120         for (i = 0; i < cmd_i; i++) {
1121                 struct iscsi_task *task = session->cmds[i];
1122                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1123
1124                 kfifo_free(tcp_task->r2tqueue);
1125                 iscsi_pool_free(&tcp_task->r2tpool);
1126         }
1127         return -ENOMEM;
1128 }
1129 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1130
1131 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1132 {
1133         int i;
1134
1135         for (i = 0; i < session->cmds_max; i++) {
1136                 struct iscsi_task *task = session->cmds[i];
1137                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1138
1139                 kfifo_free(tcp_task->r2tqueue);
1140                 iscsi_pool_free(&tcp_task->r2tpool);
1141         }
1142 }
1143 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1144
1145 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1146                               struct iscsi_stats *stats)
1147 {
1148         struct iscsi_conn *conn = cls_conn->dd_data;
1149
1150         stats->txdata_octets = conn->txdata_octets;
1151         stats->rxdata_octets = conn->rxdata_octets;
1152         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1153         stats->dataout_pdus = conn->dataout_pdus_cnt;
1154         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1155         stats->datain_pdus = conn->datain_pdus_cnt;
1156         stats->r2t_pdus = conn->r2t_pdus_cnt;
1157         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1158         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1159 }
1160 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);