diff options
| -rw-r--r-- | drivers/scsi/libiscsi_tcp.c | 1160 | ||||
| -rw-r--r-- | include/scsi/libiscsi_tcp.h | 131 |
2 files changed, 1291 insertions, 0 deletions
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c new file mode 100644 index 000000000000..e86508936314 --- /dev/null +++ b/drivers/scsi/libiscsi_tcp.c @@ -0,0 +1,1160 @@ +/* + * iSCSI over TCP/IP Data-Path lib + * + * Copyright (C) 2004 Dmitry Yusupov + * Copyright (C) 2004 Alex Aizman + * Copyright (C) 2005 - 2006 Mike Christie + * Copyright (C) 2006 Red Hat, Inc. All rights reserved. + * maintained by open-iscsi@googlegroups.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * See the file COPYING included with this distribution for more details. + * + * Credits: + * Christoph Hellwig + * FUJITA Tomonori + * Arne Redlich + * Zhenyu Wang + */ + +#include <linux/types.h> +#include <linux/list.h> +#include <linux/inet.h> +#include <linux/file.h> +#include <linux/blkdev.h> +#include <linux/crypto.h> +#include <linux/delay.h> +#include <linux/kfifo.h> +#include <linux/scatterlist.h> +#include <net/tcp.h> +#include <scsi/scsi_cmnd.h> +#include <scsi/scsi_device.h> +#include <scsi/scsi_host.h> +#include <scsi/scsi.h> +#include <scsi/scsi_transport_iscsi.h> + +#include "iscsi_tcp.h" + +MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, " + "Dmitry Yusupov <dmitry_yus@yahoo.com>, " + "Alex Aizman <itn780@yahoo.com>"); +MODULE_DESCRIPTION("iSCSI/TCP data-path"); +MODULE_LICENSE("GPL"); +#undef DEBUG_TCP + +#ifdef DEBUG_TCP +#define debug_tcp(fmt...) printk(KERN_INFO "tcp: " fmt) +#else +#define debug_tcp(fmt...) +#endif + +static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn, + struct iscsi_segment *segment); + +/* + * Scatterlist handling: inside the iscsi_segment, we + * remember an index into the scatterlist, and set data/size + * to the current scatterlist entry. For highmem pages, we + * kmap as needed. + * + * Note that the page is unmapped when we return from + * TCP's data_ready handler, so we may end up mapping and + * unmapping the same page repeatedly. The whole reason + * for this is that we shouldn't keep the page mapped + * outside the softirq. + */ + +/** + * iscsi_tcp_segment_init_sg - init indicated scatterlist entry + * @segment: the buffer object + * @sg: scatterlist + * @offset: byte offset into that sg entry + * + * This function sets up the segment so that subsequent + * data is copied to the indicated sg entry, at the given + * offset. + */ +static inline void +iscsi_tcp_segment_init_sg(struct iscsi_segment *segment, + struct scatterlist *sg, unsigned int offset) +{ + segment->sg = sg; + segment->sg_offset = offset; + segment->size = min(sg->length - offset, + segment->total_size - segment->total_copied); + segment->data = NULL; +} + +/** + * iscsi_tcp_segment_map - map the current S/G page + * @segment: iscsi_segment + * @recv: 1 if called from recv path + * + * We only need to possibly kmap data if scatter lists are being used, + * because the iscsi passthrough and internal IO paths will never use high + * mem pages. + */ +static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv) +{ + struct scatterlist *sg; + + if (segment->data != NULL || !segment->sg) + return; + + sg = segment->sg; + BUG_ON(segment->sg_mapped); + BUG_ON(sg->length == 0); + + /* + * If the page count is greater than one it is ok to send + * to the network layer's zero copy send path. If not we + * have to go the slow sendmsg path. We always map for the + * recv path. + */ + if (page_count(sg_page(sg)) >= 1 && !recv) + return; + + debug_tcp("iscsi_tcp_segment_map %s %p\n", recv ? "recv" : "xmit", + segment); + segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0); + segment->data = segment->sg_mapped + sg->offset + segment->sg_offset; +} + +void iscsi_tcp_segment_unmap(struct iscsi_segment *segment) +{ + debug_tcp("iscsi_tcp_segment_unmap %p\n", segment); + + if (segment->sg_mapped) { + debug_tcp("iscsi_tcp_segment_unmap valid\n"); + kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0); + segment->sg_mapped = NULL; + segment->data = NULL; + } +} +EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap); + +/* + * Splice the digest buffer into the buffer + */ +static inline void +iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest) +{ + segment->data = digest; + segment->digest_len = ISCSI_DIGEST_SIZE; + segment->total_size += ISCSI_DIGEST_SIZE; + segment->size = ISCSI_DIGEST_SIZE; + segment->copied = 0; + segment->sg = NULL; + segment->hash = NULL; +} + +/** + * iscsi_tcp_segment_done - check whether the segment is complete + * @segment: iscsi segment to check + * @recv: set to one of this is called from the recv path + * @copied: number of bytes copied + * + * Check if we're done receiving this segment. If the receive + * buffer is full but we expect more data, move on to the + * next entry in the scatterlist. + * + * If the amount of data we received isn't a multiple of 4, + * we will transparently receive the pad bytes, too. + * + * This function must be re-entrant. + */ +int iscsi_tcp_segment_done(struct iscsi_segment *segment, int recv, + unsigned copied) +{ + static unsigned char padbuf[ISCSI_PAD_LEN]; + struct scatterlist sg; + unsigned int pad; + + debug_tcp("copied %u %u size %u %s\n", segment->copied, copied, + segment->size, recv ? "recv" : "xmit"); + if (segment->hash && copied) { + /* + * If a segment is kmapd we must unmap it before sending + * to the crypto layer since that will try to kmap it again. + */ + iscsi_tcp_segment_unmap(segment); + + if (!segment->data) { + sg_init_table(&sg, 1); + sg_set_page(&sg, sg_page(segment->sg), copied, + segment->copied + segment->sg_offset + + segment->sg->offset); + } else + sg_init_one(&sg, segment->data + segment->copied, + copied); + crypto_hash_update(segment->hash, &sg, copied); + } + + segment->copied += copied; + if (segment->copied < segment->size) { + iscsi_tcp_segment_map(segment, recv); + return 0; + } + + segment->total_copied += segment->copied; + segment->copied = 0; + segment->size = 0; + + /* Unmap the current scatterlist page, if there is one. */ + iscsi_tcp_segment_unmap(segment); + + /* Do we have more scatterlist entries? */ + debug_tcp("total copied %u total size %u\n", segment->total_copied, + segment->total_size); + if (segment->total_copied < segment->total_size) { + /* Proceed to the next entry in the scatterlist. */ + iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg), + 0); + iscsi_tcp_segment_map(segment, recv); + BUG_ON(segment->size == 0); + return 0; + } + + /* Do we need to handle padding? */ + pad = iscsi_padding(segment->total_copied); + if (pad != 0) { + debug_tcp("consume %d pad bytes\n", pad); + segment->total_size += pad; + segment->size = pad; + segment->data = padbuf; + return 0; + } + + /* + * Set us up for transferring the data digest. hdr digest + * is completely handled in hdr done function. + */ + if (segment->hash) { + crypto_hash_final(segment->hash, segment->digest); + iscsi_tcp_segment_splice_digest(segment, + recv ? segment->recv_digest : segment->digest); + return 0; + } + + return 1; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done); + +/** + * iscsi_tcp_segment_recv - copy data to segment + * @tcp_conn: the iSCSI TCP connection + * @segment: the buffer to copy to + * @ptr: data pointer + * @len: amount of data available + * + * This function copies up to @len bytes to the + * given buffer, and returns the number of bytes + * consumed, which can actually be less than @len. + * + * If hash digest is enabled, the function will update the + * hash while copying. + * Combining these two operations doesn't buy us a lot (yet), + * but in the future we could implement combined copy+crc, + * just way we do for network layer checksums. + */ +static int +iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn, + struct iscsi_segment *segment, const void *ptr, + unsigned int len) +{ + unsigned int copy = 0, copied = 0; + + while (!iscsi_tcp_segment_done(segment, 1, copy)) { + if (copied == len) { + debug_tcp("iscsi_tcp_segment_recv copied %d bytes\n", + len); + break; + } + + copy = min(len - copied, segment->size - segment->copied); + debug_tcp("iscsi_tcp_segment_recv copying %d\n", copy); + memcpy(segment->data + segment->copied, ptr + copied, copy); + copied += copy; + } + return copied; +} + +inline void +iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen, + unsigned char digest[ISCSI_DIGEST_SIZE]) +{ + struct scatterlist sg; + + sg_init_one(&sg, hdr, hdrlen); + crypto_hash_digest(hash, &sg, hdrlen, digest); +} +EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header); + +static inline int +iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn, + struct iscsi_segment *segment) +{ + if (!segment->digest_len) + return 1; + + if (memcmp(segment->recv_digest, segment->digest, + segment->digest_len)) { + debug_scsi("digest mismatch\n"); + return 0; + } + + return 1; +} + +/* + * Helper function to set up segment buffer + */ +static inline void +__iscsi_segment_init(struct iscsi_segment *segment, size_t size, + iscsi_segment_done_fn_t *done, struct hash_desc *hash) +{ + memset(segment, 0, sizeof(*segment)); + segment->total_size = size; + segment->done = done; + + if (hash) { + segment->hash = hash; + crypto_hash_init(hash); + } +} + +inline void +iscsi_segment_init_linear(struct iscsi_segment *segment, void *data, + size_t size, iscsi_segment_done_fn_t *done, + struct hash_desc *hash) +{ + __iscsi_segment_init(segment, size, done, hash); + segment->data = data; + segment->size = size; +} +EXPORT_SYMBOL_GPL(iscsi_segment_init_linear); + +inline int +iscsi_segment_seek_sg(struct iscsi_segment *segment, + struct scatterlist *sg_list, unsigned int sg_count, + unsigned int offset, size_t size, + iscsi_segment_done_fn_t *done, struct hash_desc *hash) +{ + struct scatterlist *sg; + unsigned int i; + + debug_scsi("iscsi_segment_seek_sg offset %u size %llu\n", + offset, size); + __iscsi_segment_init(segment, size, done, hash); + for_each_sg(sg_list, sg, sg_count, i) { + debug_scsi("sg %d, len %u offset %u\n", i, sg->length, + sg->offset); + if (offset < sg->length) { + iscsi_tcp_segment_init_sg(segment, sg, offset); + return 0; + } + offset -= sg->length; + } + + return ISCSI_ERR_DATA_OFFSET; +} +EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg); + +/** + * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception + * @tcp_conn: iscsi connection to prep for + * + * This function always passes NULL for the hash argument, because when this + * function is called we do not yet know the final size of the header and want + * to delay the digest processing until we know that. + */ +void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn) +{ + debug_tcp("iscsi_tcp_hdr_recv_prep(%p%s)\n", tcp_conn, + tcp_conn->iscsi_conn->hdrdgst_en ? ", digest enabled" : ""); + iscsi_segment_init_linear(&tcp_conn->in.segment, + tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr), + iscsi_tcp_hdr_recv_done, NULL); +} +EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep); + +/* + * Handle incoming reply to any other type of command + */ +static int +iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn, + struct iscsi_segment *segment) +{ + struct iscsi_conn *conn = tcp_conn->iscsi_conn; + int rc = 0; + + if (!iscsi_tcp_dgst_verify(tcp_conn, segment)) + return ISCSI_ERR_DATA_DGST; + + rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, + conn->data, tcp_conn->in.datalen); + if (rc) + return rc; + + iscsi_tcp_hdr_recv_prep(tcp_conn); + return 0; +} + +static void +iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn) +{ + struct iscsi_conn *conn = tcp_conn->iscsi_conn; + struct hash_desc *rx_hash = NULL; + + if (conn->datadgst_en & + !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) + rx_hash = tcp_conn->rx_hash; + + iscsi_segment_init_linear(&tcp_conn->in.segment, + conn->data, tcp_conn->in.datalen, + iscsi_tcp_data_recv_done, rx_hash); +} + +/** + * iscsi_tcp_cleanup_task - free tcp_task resources + * @task: iscsi task + * + * must be called with session lock + */ +void iscsi_tcp_cleanup_task(struct iscsi_task *task) +{ + struct iscsi_tcp_task *tcp_task = task->dd_data; + struct iscsi_r2t_info *r2t; + + /* nothing to do for mgmt or pending tasks */ + if (!task->sc || task->state == ISCSI_TASK_PENDING) + return; + + /* flush task's r2t queues */ + while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) { + __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + sizeof(void*)); + debug_scsi("iscsi_tcp_cleanup_task pending r2t dropped\n"); + } + + r2t = tcp_task->r2t; + if (r2t != NULL) { + __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + sizeof(void*)); + tcp_task->r2t = NULL; + } +} +EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task); + +/** + * iscsi_tcp_data_in - SCSI Data-In Response processing + * @conn: iscsi connection + * @task: scsi command task + */ +static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task) +{ + struct iscsi_tcp_conn *tcp_conn = conn->dd_data; + struct iscsi_tcp_task *tcp_task = task->dd_data; + struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr; + int datasn = be32_to_cpu(rhdr->datasn); + unsigned total_in_length = scsi_in(task->sc)->length; + + iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr); + if (tcp_conn->in.datalen == 0) + return 0; + + if (tcp_task->exp_datasn != datasn) { + debug_tcp("%s: task->exp_datasn(%d) != rhdr->datasn(%d)\n", + __func__, tcp_task->exp_datasn, datasn); + return ISCSI_ERR_DATASN; + } + + tcp_task->exp_datasn++; + + tcp_task->data_offset = be32_to_cpu(rhdr->offset); + if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) { + debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n", + __func__, tcp_task->data_offset, + tcp_conn->in.datalen, total_in_length); + return ISCSI_ERR_DATA_OFFSET; + } + + conn->datain_pdus_cnt++; + return 0; +} + +/** + * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing + * @conn: iscsi connection + * @task: scsi command task + */ +static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) +{ + struct iscsi_session *session = conn->session; + struct iscsi_tcp_task *tcp_task = task->dd_data; + struct iscsi_tcp_conn *tcp_conn = conn->dd_data; + struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr; + struct iscsi_r2t_info *r2t; + int r2tsn = be32_to_cpu(rhdr->r2tsn); + int rc; + + if (tcp_conn->in.datalen) { + iscsi_conn_printk(KERN_ERR, conn, + "invalid R2t with datalen %d\n", + tcp_conn->in.datalen); + return ISCSI_ERR_DATALEN; + } + + if (tcp_task->exp_datasn != r2tsn){ + debug_tcp("%s: task->exp_datasn(%d) != rhdr->r2tsn(%d)\n", + __func__, tcp_task->exp_datasn, r2tsn); + return ISCSI_ERR_R2TSN; + } + + /* fill-in new R2T associated with the task */ + iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr); + + if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) { + iscsi_conn_printk(KERN_INFO, conn, + "dropping R2T itt %d in recovery.\n", + task->itt); + return 0; + } + + rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*)); + if (!rc) { + iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. " + "Target has sent more R2Ts than it " + "negotiated for or driver has has leaked.\n"); + return ISCSI_ERR_PROTO; + } + + r2t->exp_statsn = rhdr->statsn; + r2t->data_length = be32_to_cpu(rhdr->data_length); + if (r2t->data_length == 0) { + iscsi_conn_printk(KERN_ERR, conn, + "invalid R2T with zero data len\n"); + __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + sizeof(void*)); + return ISCSI_ERR_DATALEN; + } + + if (r2t->data_length > session->max_burst) + debug_scsi("invalid R2T with data len %u and max burst %u." + "Attempting to execute request.\n", + r2t->data_length, session->max_burst); + + r2t->data_offset = be32_to_cpu(rhdr->data_offset); + if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) { + iscsi_conn_printk(KERN_ERR, conn, + "invalid R2T with data len %u at offset %u " + "and total length %d\n", r2t->data_length, + r2t->data_offset, scsi_out(task->sc)->length); + __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t, + sizeof(void*)); + return ISCSI_ERR_DATALEN; + } + + r2t->ttt = rhdr->ttt; /* no flip */ + r2t->datasn = 0; + r2t->sent = 0; + + tcp_task->exp_datasn = r2tsn + 1; + __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*)); + conn->r2t_pdus_cnt++; + + iscsi_requeue_task(task); + return 0; +} + +/* + * Handle incoming reply to DataIn command + */ +static int +iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn, + struct iscsi_segment *segment) +{ + struct iscsi_conn *conn = tcp_conn->iscsi_conn; + struct iscsi_hdr *hdr = tcp_conn->in.hdr; + int rc; + + if (!iscsi_tcp_dgst_verify(tcp_conn, segment)) + return ISCSI_ERR_DATA_DGST; + + /* check for non-exceptional status */ + if (hdr->flags & ISCSI_FLAG_DATA_STATUS) { + rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0); + if (rc) + return rc; + } + + iscsi_tcp_hdr_recv_prep(tcp_conn); + return 0; +} + +/** + * iscsi_tcp_hdr_dissect - process PDU header + * @conn: iSCSI connection + * @hdr: PDU header + * + * This function analyzes the header of the PDU received, + * and performs several sanity checks. If the PDU is accompanied + * by data, the receive buffer is set up to copy the incoming data + * to the correct location. + */ +static int +iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr) +{ + int rc = 0, opcode, ahslen; + struct iscsi_tcp_conn *tcp_conn = conn->dd_data; + struct iscsi_task *task; + + /* verify PDU length */ + tcp_conn->in.datalen = ntoh24(hdr->dlength); + if (tcp_conn->in.datalen > conn->max_recv_dlength) { + iscsi_conn_printk(KERN_ERR, conn, + "iscsi_tcp: datalen %d > %d\n", + tcp_conn->in.datalen, conn->max_recv_dlength); + return ISCSI_ERR_DATALEN; + } + + /* Additional header segments. So far, we don't + * process additional headers. + */ + ahslen = hdr->hlength << 2; + + opcode = hdr->opcode & ISCSI_OPCODE_MASK; + /* verify itt (itt encoding: age+cid+itt) */ + rc = iscsi_verify_itt(conn, hdr->itt); + if (rc) + return rc; + + debug_tcp("opcode 0x%x ahslen %d datalen %d\n", + opcode, ahslen, tcp_conn->in.datalen); + + switch(opcode) { + case ISCSI_OP_SCSI_DATA_IN: + spin_lock(&conn->session->lock); + task = iscsi_itt_to_ctask(conn, hdr->itt); + if (!task) + rc = ISCSI_ERR_BAD_ITT; + else + rc = iscsi_tcp_data_in(conn, task); + if (rc) { + spin_unlock(&conn->session->lock); + break; + } + + if (tcp_conn->in.datalen) { + struct iscsi_tcp_task *tcp_task = task->dd_data; + struct hash_desc *rx_hash = NULL; + struct scsi_data_buffer *sdb = scsi_in(task->sc); + + /* + * Setup copy of Data-In into the Scsi_Cmnd + * Scatterlist case: + * We set up the iscsi_segment to point to the next + * scatterlist entry to copy to. As we go along, + * we move on to the next scatterlist entry and + * update the digest per-entry. + */ + if (conn->datadgst_en && + !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) + rx_hash = tcp_conn->rx_hash; + + debug_tcp("iscsi_tcp_begin_data_in(%p, offset=%d, " + "datalen=%d)\n", tcp_conn, + tcp_task->data_offset, + tcp_conn->in.datalen); + rc = iscsi_segment_seek_sg(&tcp_conn->in.segment, + sdb->table.sgl, + sdb->table.nents, + tcp_task->data_offset, + tcp_conn->in.datalen, + iscsi_tcp_process_data_in, + rx_hash); + spin_unlock(&conn->session->lock); + return rc; + } + rc = __iscsi_complete_pdu(conn, hdr, NULL, 0); + spin_unlock(&conn->session->lock); + break; + case ISCSI_OP_SCSI_CMD_RSP: + if (tcp_conn->in.datalen) { + iscsi_tcp_data_recv_prep(tcp_conn); + return 0; + } + rc = iscsi_complete_pdu(conn, hdr, NULL, 0); + break; + case ISCSI_OP_R2T: + spin_lock(&conn->session->lock); + task = iscsi_itt_to_ctask(conn, hdr->itt); + if (!task) + rc = ISCSI_ERR_BAD_ITT; + else if (ahslen) + rc = ISCSI_ERR_AHSLEN; + else if (task->sc->sc_data_direction == DMA_TO_DEVICE) + rc = iscsi_tcp_r2t_rsp(conn, task); + else + rc = ISCSI_ERR_PROTO; + spin_unlock(&conn->session->lock); + break; + case ISCSI_OP_LOGIN_RSP: + case ISCSI_OP_TEXT_RSP: + case ISCSI_OP_REJECT: + case ISCSI_OP_ASYNC_EVENT: + /* + * It is possible that we could get a PDU with a buffer larger + * than 8K, but there are no targets that currently do this. + * For now we fail until we find a vendor that needs it + */ + if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) { + iscsi_conn_printk(KERN_ERR, conn, + "iscsi_tcp: received buffer of " + "len %u but conn buffer is only %u " + "(opcode %0x)\n", + tcp_conn->in.datalen, + ISCSI_DEF_MAX_RECV_SEG_LEN, opcode); + rc = ISCSI_ERR_PROTO; + break; + } + + /* If there's data coming in with the response, + * receive it to the connection's buffer. + */ + if (tcp_conn->in.datalen) { + iscsi_tcp_data_recv_prep(tcp_conn); + return 0; + } + /* fall through */ + case ISCSI_OP_LOGOUT_RSP: + case ISCSI_OP_NOOP_IN: + case ISCSI_OP_SCSI_TMFUNC_RSP: + rc = iscsi_complete_pdu(conn, hdr, NULL, 0); + break; + default: + rc = ISCSI_ERR_BAD_OPCODE; + break; + } + + if (rc == 0) { + /* Anything that comes with data should have + * been handled above. */ + if (tcp_conn->in.datalen) + return ISCSI_ERR_PROTO; + iscsi_tcp_hdr_recv_prep(tcp_conn); + } + + return rc; +} + +/** + * iscsi_tcp_hdr_recv_done - process PDU header + * + * This is the callback invoked when the PDU header has + * been received. If the header is followed by additional + * header segments, we go back for more data. + */ +static int +iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn, + struct iscsi_segment *segment) +{ + struct iscsi_conn *conn = tcp_conn->iscsi_conn; + struct iscsi_hdr *hdr; + + /* Check if there are additional header segments + * *prior* to computing the digest, because we + * may need to go back to the caller for more. + */ + hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf; + if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) { + /* Bump the header length - the caller will + * just loop around and get the AHS for us, and + * call again. */ + unsigned int ahslen = hdr->hlength << 2; + + /* Make sure we don't overflow */ + if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf)) + return ISCSI_ERR_AHSLEN; + + segment->total_size += ahslen; + segment->size += ahslen; + return 0; + } + + /* We're done processing the header. See if we're doing + * header digests; if so, set up the recv_digest buffer + * and go back for more. */ + if (conn->hdrdgst_en) { + if (segment->digest_len == 0) { + /* + * Even if we offload the digest processing we + * splice it in so we can increment the skb/segment + * counters in preparation for the data segment. + */ + iscsi_tcp_segment_splice_digest(segment, + segment->recv_digest); + return 0; + } + + if (!(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) { + iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr, + segment->total_copied - ISCSI_DIGEST_SIZE, + segment->digest); + + if (!iscsi_tcp_dgst_verify(tcp_conn, segment)) + return ISCSI_ERR_HDR_DGST; + } + } + + tcp_conn->in.hdr = hdr; + return iscsi_tcp_hdr_dissect(conn, hdr); +} + +/** + * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header + * @tcp_conn: iscsi tcp conn + * + * returns non zero if we are currently processing or setup to process + * a header. + */ +inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn) +{ + return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr); + +/** + * iscsi_tcp_recv_skb - Process skb + * @conn: iscsi connection + * @skb: network buffer with header and/or data segment + * @offset: offset in skb + * @offload: bool indicating if transfer was offloaded + * + * Will return status of transfer in status. And will return + * number of bytes copied. + */ +int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb, + unsigned int offset, bool offloaded, int *status) +{ + struct iscsi_tcp_conn *tcp_conn = conn->dd_data; + struct iscsi_segment *segment = &tcp_conn->in.segment; + struct skb_seq_state seq; + unsigned int consumed = 0; + int rc = 0; + + debug_tcp("in %d bytes\n", skb->len - offset); + + if (unlikely(conn->suspend_rx)) { + debug_tcp("conn %d Rx suspended!\n", conn->id); + *status = ISCSI_TCP_SUSPENDED; + return 0; + } + + if (offloaded) { + segment->total_copied = segment->total_size; + goto segment_done; + } + + skb_prepare_seq_read(skb, offset, skb->len, &seq); + while (1) { + unsigned int avail; + const u8 *ptr; + + avail = skb_seq_read(consumed, &ptr, &seq); + if (avail == 0) { + debug_tcp("no more data avail. Consumed %d\n", + consumed); + *status = ISCSI_TCP_SKB_DONE; + skb_abort_seq_read(&seq); + goto skb_done; + } + BUG_ON(segment->copied >= segment->size); + + debug_tcp("skb %p ptr=%p avail=%u\n", skb, ptr, avail); + rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail); + BUG_ON(rc == 0); + consumed += rc; + + if (segment->total_copied >= segment->total_size) { + skb_abort_seq_read(&seq); + goto segment_done; + } + } + +segment_done: + *status = ISCSI_TCP_SEGMENT_DONE; + debug_tcp("segment done\n"); + rc = segment->done(tcp_conn, segment); + if (rc != 0) { + *status = ISCSI_TCP_CONN_ERR; + debug_tcp("Error receiving PDU, errno=%d\n", rc); + iscsi_conn_failure(conn, rc); + return 0; + } + /* The done() functions sets up the next segment. */ + +skb_done: + conn->rxdata_octets += consumed; + return consumed; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb); + +/** + * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands + * @conn: iscsi connection + * @task: scsi command task + * @sc: scsi command + */ +int iscsi_tcp_task_init(struct iscsi_task *task) +{ + struct iscsi_tcp_task *tcp_task = task->dd_data; + struct iscsi_conn *conn = task->conn; + struct scsi_cmnd *sc = task->sc; + int err; + + if (!sc) { + /* + * mgmt tasks do not have a scatterlist since they come + * in from the iscsi interface. + */ + debug_scsi("mtask deq [cid %d itt 0x%x]\n", conn->id, + task->itt); + + return conn->session->tt->init_pdu(task, 0, task->data_count); + } + + BUG_ON(__kfifo_len(tcp_task->r2tqueue)); + tcp_task->exp_datasn = 0; + + /* Prepare PDU, optionally w/ immediate data */ + debug_scsi("task deq [cid %d itt 0x%x imm %d unsol %d]\n", + conn->id, task->itt, task->imm_count, + task->unsol_r2t.data_length); + + err = conn->session->tt->init_pdu(task, 0, task->imm_count); + if (err) + return err; + task->imm_count = 0; + return 0; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_task_init); + +static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task) +{ + struct iscsi_session *session = task->conn->session; + struct iscsi_tcp_task *tcp_task = task->dd_data; + struct iscsi_r2t_info *r2t = NULL; + + if (iscsi_task_has_unsol_data(task)) + r2t = &task->unsol_r2t; + else { + spin_lock_bh(&session->lock); + if (tcp_task->r2t) { + r2t = tcp_task->r2t; + /* Continue with this R2T? */ + if (r2t->data_length <= r2t->sent) { + debug_scsi(" done with r2t %p\n", r2t); + __kfifo_put(tcp_task->r2tpool.queue, + (void *)&tcp_task->r2t, + sizeof(void *)); + tcp_task->r2t = r2t = NULL; + } + } + + if (r2t == NULL) { + __kfifo_get(tcp_task->r2tqueue, + (void *)&tcp_task->r2t, sizeof(void *)); + r2t = tcp_task->r2t; + } + spin_unlock_bh(&session->lock); + } + + return r2t; +} + +/** + * iscsi_tcp_task_xmit - xmit normal PDU task + * @task: iscsi command task + * + * We're expected to return 0 when everything was transmitted succesfully, + * -EAGAIN if there's still data in the queue, or != 0 for any other kind + * of error. + */ +int iscsi_tcp_task_xmit(struct iscsi_task *task) +{ + struct iscsi_conn *conn = task->conn; + struct iscsi_session *session = conn->session; + struct iscsi_r2t_info *r2t; + int rc = 0; + +flush: + /* Flush any pending data first. */ + rc = session->tt->xmit_pdu(task); + if (rc < 0) + return rc; + + /* mgmt command */ + if (!task->sc) { + if (task->hdr->itt == RESERVED_ITT) + iscsi_put_task(task); + return 0; + } + + /* Are we done already? */ + if (task->sc->sc_data_direction != DMA_TO_DEVICE) + return 0; + + r2t = iscsi_tcp_get_curr_r2t(task); + if (r2t == NULL) { + /* Waiting for more R2Ts to arrive. */ + debug_tcp("no R2Ts yet\n"); + return 0; + } + + rc = conn->session->tt->alloc_pdu(task); + if (rc) + return rc; + iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr); + + debug_scsi("sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n", + r2t, r2t->datasn - 1, task->hdr->itt, + r2t->data_offset + r2t->sent, r2t->data_count); + + rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent, + r2t->data_count); + if (rc) + return rc; + r2t->sent += r2t->data_count; + goto flush; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit); + +struct iscsi_cls_conn * +iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size, + uint32_t conn_idx) + +{ + struct iscsi_conn *conn; + struct iscsi_cls_conn *cls_conn; + struct iscsi_tcp_conn *tcp_conn; + + cls_conn = iscsi_conn_setup(cls_session, sizeof(*tcp_conn), conn_idx); + if (!cls_conn) + return NULL; + conn = cls_conn->dd_data; + /* + * due to strange issues with iser these are not set + * in iscsi_conn_setup + */ + conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN; + + tcp_conn = conn->dd_data; + tcp_conn->iscsi_conn = conn; + + tcp_conn->dd_data = kzalloc(dd_data_size, GFP_KERNEL); + if (!tcp_conn->dd_data) { + iscsi_conn_teardown(cls_conn); + return NULL; + } + return cls_conn; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup); + +void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn) +{ + struct iscsi_conn *conn = cls_conn->dd_data; + struct iscsi_tcp_conn *tcp_conn = conn->dd_data; + + kfree(tcp_conn->dd_data); + iscsi_conn_teardown(cls_conn); +} +EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown); + +int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session) +{ + int i; + int cmd_i; + + /* + * initialize per-task: R2T pool and xmit queue + */ + for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) { + struct iscsi_task *task = session->cmds[cmd_i]; + struct iscsi_tcp_task *tcp_task = task->dd_data; + + /* + * pre-allocated x2 as much r2ts to handle race when + * target acks DataOut faster than we data_xmit() queues + * could replenish r2tqueue. + */ + + /* R2T pool */ + if (iscsi_pool_init(&tcp_task->r2tpool, + session->max_r2t * 2, NULL, + sizeof(struct iscsi_r2t_info))) { + goto r2t_alloc_fail; + } + + /* R2T xmit queue */ + tcp_task->r2tqueue = kfifo_alloc( + session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL); + if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) { + iscsi_pool_free(&tcp_task->r2tpool); + goto r2t_alloc_fail; + } + } + + return 0; + +r2t_alloc_fail: + for (i = 0; i < cmd_i; i++) { + struct iscsi_task *task = session->cmds[i]; + struct iscsi_tcp_task *tcp_task = task->dd_data; + + kfifo_free(tcp_task->r2tqueue); + iscsi_pool_free(&tcp_task->r2tpool); + } + return -ENOMEM; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc); + +void iscsi_tcp_r2tpool_free(struct iscsi_session *session) +{ + int i; + + for (i = 0; i < session->cmds_max; i++) { + struct iscsi_task *task = session->cmds[i]; + struct iscsi_tcp_task *tcp_task = task->dd_data; + + kfifo_free(tcp_task->r2tqueue); + iscsi_pool_free(&tcp_task->r2tpool); + } +} +EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free); + +void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn, + struct iscsi_stats *stats) +{ + struct iscsi_conn *conn = cls_conn->dd_data; + + stats->txdata_octets = conn->txdata_octets; + stats->rxdata_octets = conn->rxdata_octets; + stats->scsicmd_pdus = conn->scsicmd_pdus_cnt; + stats->dataout_pdus = conn->dataout_pdus_cnt; + stats->scsirsp_pdus = conn->scsirsp_pdus_cnt; + stats->datain_pdus = conn->datain_pdus_cnt; + stats->r2t_pdus = conn->r2t_pdus_cnt; + stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt; + stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt; +} +EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats); diff --git a/include/scsi/libiscsi_tcp.h b/include/scsi/libiscsi_tcp.h new file mode 100644 index 000000000000..e6bf8ef276bb --- /dev/null +++ b/include/scsi/libiscsi_tcp.h @@ -0,0 +1,131 @@ +/* + * iSCSI over TCP/IP Data-Path lib + * + * Copyright (C) 2008 Mike Christie + * Copyright (C) 2008 Red Hat, Inc. All rights reserved. + * maintained by open-iscsi@googlegroups.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * See the file COPYING included with this distribution for more details. + */ + +#ifndef LIBISCSI_TCP_H +#define LIBISCSI_TCP_H + +#include <scsi/libiscsi.h> + +struct iscsi_tcp_conn; +struct iscsi_segment; +struct sk_buff; +struct hash_desc; + +typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *, + struct iscsi_segment *); + +struct iscsi_segment { + unsigned char *data; + unsigned int size; + unsigned int copied; + unsigned int total_size; + unsigned int total_copied; + + struct hash_desc *hash; + unsigned char recv_digest[ISCSI_DIGEST_SIZE]; + unsigned char digest[ISCSI_DIGEST_SIZE]; + unsigned int digest_len; + + struct scatterlist *sg; + void *sg_mapped; + unsigned int sg_offset; + + iscsi_segment_done_fn_t *done; +}; + +/* Socket connection recieve helper */ +struct iscsi_tcp_recv { + struct iscsi_hdr *hdr; + struct iscsi_segment segment; + + /* Allocate buffer for BHS + AHS */ + uint32_t hdr_buf[64]; + + /* copied and flipped values */ + int datalen; +}; + +struct iscsi_tcp_conn { + struct iscsi_conn *iscsi_conn; + void *dd_data; + int stop_stage; /* conn_stop() flag: * + * stop to recover, * + * stop to terminate */ + /* control data */ + struct iscsi_tcp_recv in; /* TCP receive context */ + /* CRC32C (Rx) LLD should set this is they do not offload */ + struct hash_desc *rx_hash; +}; + +struct iscsi_tcp_task { + uint32_t exp_datasn; /* expected target's R2TSN/DataSN */ + int data_offset; + struct iscsi_r2t_info *r2t; /* in progress solict R2T */ + struct iscsi_pool r2tpool; + struct kfifo *r2tqueue; + void *dd_data; +}; + +enum { + ISCSI_TCP_SEGMENT_DONE, /* curr seg has been processed */ + ISCSI_TCP_SKB_DONE, /* skb is out of data */ + ISCSI_TCP_CONN_ERR, /* iscsi layer has fired a conn err */ + ISCSI_TCP_SUSPENDED, /* conn is suspended */ +}; + +extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn); +extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb, + unsigned int offset, bool offloaded, int *status); +extern void iscsi_tcp_cleanup_task(struct iscsi_task *task); +extern int iscsi_tcp_task_init(struct iscsi_task *task); +extern int iscsi_tcp_task_xmit(struct iscsi_task *task); + +/* segment helpers */ +extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn); +extern int iscsi_tcp_segment_done(struct iscsi_segment *segment, int recv, + unsigned copied); +extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment); + +extern void iscsi_segment_init_linear(struct iscsi_segment *segment, + void *data, size_t size, + iscsi_segment_done_fn_t *done, + struct hash_desc *hash); +extern int +iscsi_segment_seek_sg(struct iscsi_segment *segment, + struct scatterlist *sg_list, unsigned int sg_count, + unsigned int offset, size_t size, + iscsi_segment_done_fn_t *done, struct hash_desc *hash); + +/* digest helpers */ +extern void iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, + size_t hdrlen, + unsigned char digest[ISCSI_DIGEST_SIZE]); +extern struct iscsi_cls_conn * +iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size, + uint32_t conn_idx); +extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn); + +/* misc helpers */ +extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session); +extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session); + +extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn, + struct iscsi_stats *stats); +#endif /* LIBISCSI_TCP_H */ |