/* * Copyright (C) 2016-2017 Red Hat, Inc. * Copyright (C) 2005 Anthony Liguori * * Network Block Device * * 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; under version 2 of the License. * * 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #ifndef NBD_H #define NBD_H #include "qemu-common.h" #include "qemu/option.h" #include "io/channel-socket.h" #include "crypto/tlscreds.h" /* Handshake phase structs - this struct is passed on the wire */ struct nbd_option { uint64_t magic; /* NBD_OPTS_MAGIC */ uint32_t option; /* NBD_OPT_* */ uint32_t length; } QEMU_PACKED; typedef struct nbd_option nbd_option; struct nbd_opt_reply { uint64_t magic; /* NBD_REP_MAGIC */ uint32_t option; /* NBD_OPT_* */ uint32_t type; /* NBD_REP_* */ uint32_t length; } QEMU_PACKED; typedef struct nbd_opt_reply nbd_opt_reply; /* Transmission phase structs * * Note: these are _NOT_ the same as the network representation of an NBD * request and reply! */ struct NBDRequest { uint64_t handle; uint64_t from; uint32_t len; uint16_t flags; /* NBD_CMD_FLAG_* */ uint16_t type; /* NBD_CMD_* */ }; typedef struct NBDRequest NBDRequest; typedef struct NBDSimpleReply { uint32_t magic; /* NBD_SIMPLE_REPLY_MAGIC */ uint32_t error; uint64_t handle; } QEMU_PACKED NBDSimpleReply; /* Header of all structured replies */ typedef struct NBDStructuredReplyChunk { uint32_t magic; /* NBD_STRUCTURED_REPLY_MAGIC */ uint16_t flags; /* combination of NBD_REPLY_FLAG_* */ uint16_t type; /* NBD_REPLY_TYPE_* */ uint64_t handle; /* request handle */ uint32_t length; /* length of payload */ } QEMU_PACKED NBDStructuredReplyChunk; typedef union NBDReply { NBDSimpleReply simple; NBDStructuredReplyChunk structured; struct { /* @magic and @handle fields have the same offset and size both in * simple reply and structured reply chunk, so let them be accessible * without ".simple." or ".structured." specification */ uint32_t magic; uint32_t _skip; uint64_t handle; } QEMU_PACKED; } NBDReply; /* Header of chunk for NBD_REPLY_TYPE_OFFSET_DATA */ typedef struct NBDStructuredReadData { NBDStructuredReplyChunk h; /* h.length >= 9 */ uint64_t offset; /* At least one byte of data payload follows, calculated from h.length */ } QEMU_PACKED NBDStructuredReadData; /* Complete chunk for NBD_REPLY_TYPE_OFFSET_HOLE */ typedef struct NBDStructuredReadHole { NBDStructuredReplyChunk h; /* h.length == 12 */ uint64_t offset; uint32_t length; } QEMU_PACKED NBDStructuredReadHole; /* Header of all NBD_REPLY_TYPE_ERROR* errors */ typedef struct NBDStructuredError { NBDStructuredReplyChunk h; /* h.length >= 6 */ uint32_t error; uint16_t message_length; } QEMU_PACKED NBDStructuredError; /* Transmission (export) flags: sent from server to client during handshake, but describe what will happen during transmission */ #define NBD_FLAG_HAS_FLAGS (1 << 0) /* Flags are there */ #define NBD_FLAG_READ_ONLY (1 << 1) /* Device is read-only */ #define NBD_FLAG_SEND_FLUSH (1 << 2) /* Send FLUSH */ #define NBD_FLAG_SEND_FUA (1 << 3) /* Send FUA (Force Unit Access) */ #define NBD_FLAG_ROTATIONAL (1 << 4) /* Use elevator algorithm - rotational media */ #define NBD_FLAG_SEND_TRIM (1 << 5) /* Send TRIM (discard) */ #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */ #define NBD_FLAG_SEND_DF (1 << 7) /* Send DF (Do not Fragment) */ /* New-style handshake (global) flags, sent from server to client, and control what will happen during handshake phase. */ #define NBD_FLAG_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ #define NBD_FLAG_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ /* New-style client flags, sent from client to server to control what happens during handshake phase. */ #define NBD_FLAG_C_FIXED_NEWSTYLE (1 << 0) /* Fixed newstyle protocol. */ #define NBD_FLAG_C_NO_ZEROES (1 << 1) /* End handshake without zeroes. */ /* Option requests. */ #define NBD_OPT_EXPORT_NAME (1) #define NBD_OPT_ABORT (2) #define NBD_OPT_LIST (3) /* #define NBD_OPT_PEEK_EXPORT (4) not in use */ #define NBD_OPT_STARTTLS (5) #define NBD_OPT_INFO (6) #define NBD_OPT_GO (7) #define NBD_OPT_STRUCTURED_REPLY (8) /* Option reply types. */ #define NBD_REP_ERR(value) ((UINT32_C(1) << 31) | (value)) #define NBD_REP_ACK (1) /* Data sending finished. */ #define NBD_REP_SERVER (2) /* Export description. */ #define NBD_REP_INFO (3) /* NBD_OPT_INFO/GO. */ #define NBD_REP_ERR_UNSUP NBD_REP_ERR(1) /* Unknown option */ #define NBD_REP_ERR_POLICY NBD_REP_ERR(2) /* Server denied */ #define NBD_REP_ERR_INVALID NBD_REP_ERR(3) /* Invalid length */ #define NBD_REP_ERR_PLATFORM NBD_REP_ERR(4) /* Not compiled in */ #define NBD_REP_ERR_TLS_REQD NBD_REP_ERR(5) /* TLS required */ #define NBD_REP_ERR_UNKNOWN NBD_REP_ERR(6) /* Export unknown */ #define NBD_REP_ERR_SHUTDOWN NBD_REP_ERR(7) /* Server shutting down */ #define NBD_REP_ERR_BLOCK_SIZE_REQD NBD_REP_ERR(8) /* Need INFO_BLOCK_SIZE */ /* Info types, used during NBD_REP_INFO */ #define NBD_INFO_EXPORT 0 #define NBD_INFO_NAME 1 #define NBD_INFO_DESCRIPTION 2 #define NBD_INFO_BLOCK_SIZE 3 /* Request flags, sent from client to server during transmission phase */ #define NBD_CMD_FLAG_FUA (1 << 0) /* 'force unit access' during write */ #define NBD_CMD_FLAG_NO_HOLE (1 << 1) /* don't punch hole on zero run */ #define NBD_CMD_FLAG_DF (1 << 2) /* don't fragment structured read */ /* Supported request types */ enum { NBD_CMD_READ = 0, NBD_CMD_WRITE = 1, NBD_CMD_DISC = 2, NBD_CMD_FLUSH = 3, NBD_CMD_TRIM = 4, /* 5 reserved for failed experiment NBD_CMD_CACHE */ NBD_CMD_WRITE_ZEROES = 6, }; #define NBD_DEFAULT_PORT 10809 /* Maximum size of a single READ/WRITE data buffer */ #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024) /* Maximum size of an export name. The NBD spec requires 256 and * suggests that servers support up to 4096, but we stick to only the * required size so that we can stack-allocate the names, and because * going larger would require an audit of more code to make sure we * aren't overflowing some other buffer. */ #define NBD_MAX_NAME_SIZE 256 /* Two types of reply structures */ #define NBD_SIMPLE_REPLY_MAGIC 0x67446698 #define NBD_STRUCTURED_REPLY_MAGIC 0x668e33ef /* Structured reply flags */ #define NBD_REPLY_FLAG_DONE (1 << 0) /* This reply-chunk is last */ /* Structured reply types */ #define NBD_REPLY_ERR(value) ((1 << 15) | (value)) #define NBD_REPLY_TYPE_NONE 0 #define NBD_REPLY_TYPE_OFFSET_DATA 1 #define NBD_REPLY_TYPE_OFFSET_HOLE 2 #define NBD_REPLY_TYPE_ERROR NBD_REPLY_ERR(1) #define NBD_REPLY_TYPE_ERROR_OFFSET NBD_REPLY_ERR(2) static inline bool nbd_reply_type_is_error(int type) { return type & (1 << 15); } /* NBD errors are based on errno numbers, so there is a 1:1 mapping, * but only a limited set of errno values is specified in the protocol. * Everything else is squashed to EINVAL. */ #define NBD_SUCCESS 0 #define NBD_EPERM 1 #define NBD_EIO 5 #define NBD_ENOMEM 12 #define NBD_EINVAL 22 #define NBD_ENOSPC 28 #define NBD_EOVERFLOW 75 #define NBD_ESHUTDOWN 108 /* Details collected by NBD_OPT_EXPORT_NAME and NBD_OPT_GO */ struct NBDExportInfo { /* Set by client before nbd_receive_negotiate() */ bool request_sizes; /* In-out fields, set by client before nbd_receive_negotiate() and * updated by server results during nbd_receive_negotiate() */ bool structured_reply; /* Set by server results during nbd_receive_negotiate() */ uint64_t size; uint16_t flags; uint32_t min_block; uint32_t opt_block; uint32_t max_block; }; typedef struct NBDExportInfo NBDExportInfo; int nbd_receive_negotiate(QIOChannel *ioc, const char *name, QCryptoTLSCreds *tlscreds, const char *hostname, QIOChannel **outioc, NBDExportInfo *info, Error **errp); int nbd_init(int fd, QIOChannelSocket *sioc, NBDExportInfo *info, Error **errp); int nbd_send_request(QIOChannel *ioc, NBDRequest *request); int nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp); int nbd_client(int fd); int nbd_disconnect(int fd); int nbd_errno_to_system_errno(int err); typedef struct NBDExport NBDExport; typedef struct NBDClient NBDClient; NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, uint16_t nbdflags, void (*close)(NBDExport *), bool writethrough, BlockBackend *on_eject_blk, Error **errp); void nbd_export_close(NBDExport *exp); void nbd_export_get(NBDExport *exp); void nbd_export_put(NBDExport *exp); BlockBackend *nbd_export_get_blockdev(NBDExport *exp); NBDExport *nbd_export_find(const char *name); void nbd_export_set_name(NBDExport *exp, const char *name); void nbd_export_set_description(NBDExport *exp, const char *description); void nbd_export_close_all(void); void nbd_client_new(NBDExport *exp, QIOChannelSocket *sioc, QCryptoTLSCreds *tlscreds, const char *tlsaclname, void (*close_fn)(NBDClient *, bool)); void nbd_client_get(NBDClient *client); void nbd_client_put(NBDClient *client); void nbd_server_start(SocketAddress *addr, const char *tls_creds, Error **errp); /* nbd_read * Reads @size bytes from @ioc. Returns 0 on success. */ static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size, Error **errp) { return qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0; } static inline bool nbd_reply_is_simple(NBDReply *reply) { return reply->magic == NBD_SIMPLE_REPLY_MAGIC; } static inline bool nbd_reply_is_structured(NBDReply *reply) { return reply->magic == NBD_STRUCTURED_REPLY_MAGIC; } const char *nbd_reply_type_lookup(uint16_t type); #endif