Handle nbd CACHE command. Just do read, without sending read data back. Cache mechanism should be done by exported node driver chain. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20180413143156.11409-1-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: fix two missing case labels in switch statements] Signed-off-by: Eric Blake <eblake@redhat.com>
346 lines
12 KiB
C
346 lines
12 KiB
C
/*
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* Copyright (C) 2016-2017 Red Hat, Inc.
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* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
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*
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* Network Block Device
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef NBD_H
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#define NBD_H
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#include "qapi/qapi-types-block.h"
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#include "io/channel-socket.h"
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#include "crypto/tlscreds.h"
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/* Handshake phase structs - this struct is passed on the wire */
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struct NBDOption {
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uint64_t magic; /* NBD_OPTS_MAGIC */
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uint32_t option; /* NBD_OPT_* */
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uint32_t length;
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} QEMU_PACKED;
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typedef struct NBDOption NBDOption;
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struct NBDOptionReply {
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uint64_t magic; /* NBD_REP_MAGIC */
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uint32_t option; /* NBD_OPT_* */
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uint32_t type; /* NBD_REP_* */
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uint32_t length;
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} QEMU_PACKED;
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typedef struct NBDOptionReply NBDOptionReply;
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typedef struct NBDOptionReplyMetaContext {
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NBDOptionReply h; /* h.type = NBD_REP_META_CONTEXT, h.length > 4 */
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uint32_t context_id;
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/* meta context name follows */
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} QEMU_PACKED NBDOptionReplyMetaContext;
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/* Transmission phase structs
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*
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* Note: these are _NOT_ the same as the network representation of an NBD
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* request and reply!
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*/
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struct NBDRequest {
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uint64_t handle;
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uint64_t from;
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uint32_t len;
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uint16_t flags; /* NBD_CMD_FLAG_* */
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uint16_t type; /* NBD_CMD_* */
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};
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typedef struct NBDRequest NBDRequest;
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typedef struct NBDSimpleReply {
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uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC */
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uint32_t error;
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uint64_t handle;
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} QEMU_PACKED NBDSimpleReply;
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/* Header of all structured replies */
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typedef struct NBDStructuredReplyChunk {
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uint32_t magic; /* NBD_STRUCTURED_REPLY_MAGIC */
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uint16_t flags; /* combination of NBD_REPLY_FLAG_* */
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uint16_t type; /* NBD_REPLY_TYPE_* */
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uint64_t handle; /* request handle */
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uint32_t length; /* length of payload */
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} QEMU_PACKED NBDStructuredReplyChunk;
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typedef union NBDReply {
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NBDSimpleReply simple;
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NBDStructuredReplyChunk structured;
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struct {
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/* @magic and @handle fields have the same offset and size both in
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* simple reply and structured reply chunk, so let them be accessible
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* without ".simple." or ".structured." specification
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*/
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uint32_t magic;
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uint32_t _skip;
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uint64_t handle;
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} QEMU_PACKED;
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} NBDReply;
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/* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */
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typedef struct NBDStructuredReadData {
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NBDStructuredReplyChunk h; /* h.length >= 9 */
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uint64_t offset;
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/* At least one byte of data payload follows, calculated from h.length */
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} QEMU_PACKED NBDStructuredReadData;
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/* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */
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typedef struct NBDStructuredReadHole {
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NBDStructuredReplyChunk h; /* h.length == 12 */
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uint64_t offset;
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uint32_t length;
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} QEMU_PACKED NBDStructuredReadHole;
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/* Header of all NBD_REPLY_TYPE_ERROR* errors */
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typedef struct NBDStructuredError {
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NBDStructuredReplyChunk h; /* h.length >= 6 */
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uint32_t error;
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uint16_t message_length;
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} QEMU_PACKED NBDStructuredError;
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/* Header of NBD_REPLY_TYPE_BLOCK_STATUS */
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typedef struct NBDStructuredMeta {
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NBDStructuredReplyChunk h; /* h.length >= 12 (at least one extent) */
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uint32_t context_id;
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/* extents follows */
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} QEMU_PACKED NBDStructuredMeta;
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/* Extent chunk for NBD_REPLY_TYPE_BLOCK_STATUS */
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typedef struct NBDExtent {
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uint32_t length;
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uint32_t flags; /* NBD_STATE_* */
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} QEMU_PACKED NBDExtent;
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/* Transmission (export) flags: sent from server to client during handshake,
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but describe what will happen during transmission */
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#define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */
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#define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */
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#define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */
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#define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */
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#define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm -
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rotational media */
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#define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */
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#define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */
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#define NBD_FLAG_SEND_DF (1 << 7) /* Send DF (Do not Fragment) */
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#define NBD_FLAG_SEND_CACHE (1 << 8) /* Send CACHE (prefetch) */
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/* New-style handshake (global) flags, sent from server to client, and
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control what will happen during handshake phase. */
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#define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
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#define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */
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/* New-style client flags, sent from client to server to control what happens
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during handshake phase. */
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#define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */
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#define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */
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/* Option requests. */
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#define NBD_OPT_EXPORT_NAME (1)
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#define NBD_OPT_ABORT (2)
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#define NBD_OPT_LIST (3)
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/* #define NBD_OPT_PEEK_EXPORT (4) not in use */
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#define NBD_OPT_STARTTLS (5)
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#define NBD_OPT_INFO (6)
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#define NBD_OPT_GO (7)
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#define NBD_OPT_STRUCTURED_REPLY (8)
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#define NBD_OPT_LIST_META_CONTEXT (9)
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#define NBD_OPT_SET_META_CONTEXT (10)
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/* Option reply types. */
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#define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value))
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#define NBD_REP_ACK (1) /* Data sending finished. */
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#define NBD_REP_SERVER (2) /* Export description. */
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#define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */
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#define NBD_REP_META_CONTEXT (4) /* NBD_OPT_{LIST,SET}_META_CONTEXT */
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#define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */
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#define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */
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#define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */
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#define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */
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#define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */
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#define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */
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#define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */
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#define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */
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/* Info types, used during NBD_REP_INFO */
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#define NBD_INFO_EXPORT 0
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#define NBD_INFO_NAME 1
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#define NBD_INFO_DESCRIPTION 2
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#define NBD_INFO_BLOCK_SIZE 3
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/* Request flags, sent from client to server during transmission phase */
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#define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */
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#define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */
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#define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */
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#define NBD_CMD_FLAG_REQ_ONE (1 << 3) /* only one extent in BLOCK_STATUS
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* reply chunk */
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/* Supported request types */
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enum {
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NBD_CMD_READ = 0,
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NBD_CMD_WRITE = 1,
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NBD_CMD_DISC = 2,
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NBD_CMD_FLUSH = 3,
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NBD_CMD_TRIM = 4,
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NBD_CMD_CACHE = 5,
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NBD_CMD_WRITE_ZEROES = 6,
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NBD_CMD_BLOCK_STATUS = 7,
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};
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#define NBD_DEFAULT_PORT 10809
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/* Maximum size of a single READ/WRITE data buffer */
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#define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024)
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/* Maximum size of an export name. The NBD spec requires 256 and
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* suggests that servers support up to 4096, but we stick to only the
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* required size so that we can stack-allocate the names, and because
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* going larger would require an audit of more code to make sure we
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* aren't overflowing some other buffer. */
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#define NBD_MAX_NAME_SIZE 256
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/* Two types of reply structures */
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#define NBD_SIMPLE_REPLY_MAGIC 0x67446698
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#define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef
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/* Structured reply flags */
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#define NBD_REPLY_FLAG_DONE (1 << 0) /* This reply-chunk is last */
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/* Structured reply types */
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#define NBD_REPLY_ERR(value) ((1 << 15) | (value))
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#define NBD_REPLY_TYPE_NONE 0
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#define NBD_REPLY_TYPE_OFFSET_DATA 1
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#define NBD_REPLY_TYPE_OFFSET_HOLE 2
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#define NBD_REPLY_TYPE_BLOCK_STATUS 5
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#define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1)
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#define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_ERR(2)
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/* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */
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#define NBD_STATE_HOLE (1 << 0)
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#define NBD_STATE_ZERO (1 << 1)
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/* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */
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#define NBD_STATE_DIRTY (1 << 0)
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static inline bool nbd_reply_type_is_error(int type)
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{
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return type & (1 << 15);
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}
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/* NBD errors are based on errno numbers, so there is a 1:1 mapping,
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* but only a limited set of errno values is specified in the protocol.
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* Everything else is squashed to EINVAL.
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*/
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#define NBD_SUCCESS 0
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#define NBD_EPERM 1
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#define NBD_EIO 5
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#define NBD_ENOMEM 12
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#define NBD_EINVAL 22
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#define NBD_ENOSPC 28
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#define NBD_EOVERFLOW 75
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#define NBD_ESHUTDOWN 108
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/* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */
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struct NBDExportInfo {
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/* Set by client before nbd_receive_negotiate() */
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bool request_sizes;
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/* In-out fields, set by client before nbd_receive_negotiate() and
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* updated by server results during nbd_receive_negotiate() */
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bool structured_reply;
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bool base_allocation; /* base:allocation context for NBD_CMD_BLOCK_STATUS */
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/* Set by server results during nbd_receive_negotiate() */
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uint64_t size;
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uint16_t flags;
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uint32_t min_block;
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uint32_t opt_block;
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uint32_t max_block;
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uint32_t meta_base_allocation_id;
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};
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typedef struct NBDExportInfo NBDExportInfo;
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int nbd_receive_negotiate(QIOChannel *ioc, const char *name,
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QCryptoTLSCreds *tlscreds, const char *hostname,
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QIOChannel **outioc, NBDExportInfo *info,
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Error **errp);
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int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info,
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Error **errp);
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int nbd_send_request(QIOChannel *ioc, NBDRequest *request);
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int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp);
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int nbd_client(int fd);
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int nbd_disconnect(int fd);
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int nbd_errno_to_system_errno(int err);
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typedef struct NBDExport NBDExport;
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typedef struct NBDClient NBDClient;
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NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
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uint16_t nbdflags, void (*close)(NBDExport *),
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bool writethrough, BlockBackend *on_eject_blk,
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Error **errp);
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void nbd_export_close(NBDExport *exp);
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void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
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void nbd_export_get(NBDExport *exp);
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void nbd_export_put(NBDExport *exp);
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BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
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NBDExport *nbd_export_find(const char *name);
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void nbd_export_set_name(NBDExport *exp, const char *name);
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void nbd_export_set_description(NBDExport *exp, const char *description);
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void nbd_export_close_all(void);
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void nbd_client_new(NBDExport *exp,
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QIOChannelSocket *sioc,
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QCryptoTLSCreds *tlscreds,
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const char *tlsaclname,
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void (*close_fn)(NBDClient *, bool));
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void nbd_client_get(NBDClient *client);
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void nbd_client_put(NBDClient *client);
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void nbd_server_start(SocketAddress *addr, const char *tls_creds,
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Error **errp);
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void nbd_export_bitmap(NBDExport *exp, const char *bitmap,
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const char *bitmap_export_name, Error **errp);
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/* nbd_read
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* Reads @size bytes from @ioc. Returns 0 on success.
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*/
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static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
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Error **errp)
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{
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return qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
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}
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static inline bool nbd_reply_is_simple(NBDReply *reply)
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{
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return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
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}
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static inline bool nbd_reply_is_structured(NBDReply *reply)
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{
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return reply->magic == NBD_STRUCTURED_REPLY_MAGIC;
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}
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const char *nbd_reply_type_lookup(uint16_t type);
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#endif
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