8ecaeae822
NBD_OPT_EXPORT_NAME is lousy: per the NBD protocol, any failure requires the server to close the connection rather than report an error to us. Therefore, upstream NBD recently added NBD_OPT_GO as the improved version of the option that does what we want [1]: it reports sane errors on failures, and on success provides at least as much info as NBD_OPT_EXPORT_NAME. [1] https://github.com/NetworkBlockDevice/nbd/blob/extension-info/doc/proto.md This is a first cut at use of the information types. Note that we do not need to use NBD_OPT_INFO, and that use of NBD_OPT_GO means we no longer have to use NBD_OPT_LIST to learn whether a server requires TLS (this requires servers that gracefully handle unknown NBD_OPT, many servers prior to qemu 2.5 were buggy, but I have patched qemu, upstream nbd, and nbdkit in the meantime, in part because of interoperability testing with this patch). We still fall back to NBD_OPT_LIST when NBD_OPT_GO is not supported on the server, as it is still one last chance for a nicer error message. Later patches will use further info, like NBD_INFO_BLOCK_SIZE. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20170707203049.534-8-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
141 lines
4.0 KiB
C
141 lines
4.0 KiB
C
/*
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* NBD Internal Declarations
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*
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* Copyright (C) 2016 Red Hat, Inc.
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#ifndef NBD_INTERNAL_H
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#define NBD_INTERNAL_H
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#include "block/nbd.h"
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#include "sysemu/block-backend.h"
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#include "io/channel-tls.h"
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#include "qemu/coroutine.h"
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#include "qemu/iov.h"
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#ifndef _WIN32
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#include <sys/ioctl.h>
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#endif
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#if defined(__sun__) || defined(__HAIKU__)
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#include <sys/ioccom.h>
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#endif
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#ifdef __linux__
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#include <linux/fs.h>
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#endif
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#include "qemu/bswap.h"
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#include "qemu/queue.h"
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#include "qemu/main-loop.h"
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/* This is all part of the "official" NBD API.
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*
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* The most up-to-date documentation is available at:
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* https://github.com/yoe/nbd/blob/master/doc/proto.md
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*/
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/* Size of all NBD_OPT_*, without payload */
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#define NBD_REQUEST_SIZE (4 + 2 + 2 + 8 + 8 + 4)
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/* Size of all NBD_REP_* sent in answer to most NBD_OPT_*, without payload */
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#define NBD_REPLY_SIZE (4 + 4 + 8)
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#define NBD_REQUEST_MAGIC 0x25609513
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#define NBD_REPLY_MAGIC 0x67446698
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#define NBD_OPTS_MAGIC 0x49484156454F5054LL
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#define NBD_CLIENT_MAGIC 0x0000420281861253LL
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#define NBD_REP_MAGIC 0x0003e889045565a9LL
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#define NBD_SET_SOCK _IO(0xab, 0)
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#define NBD_SET_BLKSIZE _IO(0xab, 1)
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#define NBD_SET_SIZE _IO(0xab, 2)
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#define NBD_DO_IT _IO(0xab, 3)
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#define NBD_CLEAR_SOCK _IO(0xab, 4)
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#define NBD_CLEAR_QUE _IO(0xab, 5)
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#define NBD_PRINT_DEBUG _IO(0xab, 6)
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#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
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#define NBD_DISCONNECT _IO(0xab, 8)
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#define NBD_SET_TIMEOUT _IO(0xab, 9)
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#define NBD_SET_FLAGS _IO(0xab, 10)
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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_ESHUTDOWN 108
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/* nbd_read_eof
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* Tries to read @size bytes from @ioc. Returns number of bytes actually read.
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* May return a value >= 0 and < size only on EOF, i.e. when iteratively called
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* qio_channel_readv() returns 0. So, there is no need to call nbd_read_eof
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* iteratively.
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*/
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static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
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Error **errp)
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{
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struct iovec iov = { .iov_base = buffer, .iov_len = size };
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/* Sockets are kept in blocking mode in the negotiation phase. After
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* that, a non-readable socket simply means that another thread stole
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* our request/reply. Synchronization is done with recv_coroutine, so
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* that this is coroutine-safe.
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*/
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return nbd_rwv(ioc, &iov, 1, size, true, errp);
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}
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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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ssize_t ret = nbd_read_eof(ioc, buffer, size, errp);
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if (ret >= 0 && ret != size) {
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ret = -EINVAL;
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error_setg(errp, "End of file");
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}
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return ret < 0 ? ret : 0;
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}
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/* nbd_write
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* Writes @size bytes to @ioc. Returns 0 on success.
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*/
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static inline int nbd_write(QIOChannel *ioc, const void *buffer, size_t size,
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Error **errp)
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{
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struct iovec iov = { .iov_base = (void *) buffer, .iov_len = size };
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ssize_t ret = nbd_rwv(ioc, &iov, 1, size, false, errp);
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assert(ret < 0 || ret == size);
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return ret < 0 ? ret : 0;
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}
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struct NBDTLSHandshakeData {
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GMainLoop *loop;
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bool complete;
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Error *error;
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};
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void nbd_tls_handshake(QIOTask *task,
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void *opaque);
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const char *nbd_opt_lookup(uint32_t opt);
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const char *nbd_rep_lookup(uint32_t rep);
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const char *nbd_info_lookup(uint16_t info);
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const char *nbd_cmd_lookup(uint16_t info);
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int nbd_drop(QIOChannel *ioc, size_t size, Error **errp);
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#endif
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