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5f66d060db
A typo in commit 23e099c set the size of buf[] used in response
to NBD_OPT_EXPORT_NAME according to the length needed for old-style
negotiation (4 bytes of flag information) instead of the intended
2 bytes used in new style. If the client doesn't enable
NBD_FLAG_C_NO_ZEROES, then the server sends two bytes too many,
and is then out of sync in response to the client's next command
(the bug is masked when modern qemu is the client, since we enable
the no zeroes flag).
While touching this code, add some more defines to nbd_internal.h
rather than having quite so many magic numbers in the .c; also,
use "" initialization rather than memset(), and tweak the oldstyle
negotiation to better match the spec description of the layout
(since the spec is big-endian, skipping two bytes as 0 followed by
writing a 2-byte flag is the same as writing a zero-extended 4-byte
flag), to make it a bit easier to follow compared to the spec.
[checkpatch.pl has some false positives in the comments]
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170717192635.17880-3-eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
145 lines
4.2 KiB
C
145 lines
4.2 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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/* Size of reply to NBD_OPT_EXPORT_NAME */
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#define NBD_REPLY_EXPORT_NAME_SIZE (8 + 2 + 124)
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/* Size of oldstyle negotiation */
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#define NBD_OLDSTYLE_NEGOTIATE_SIZE (8 + 8 + 8 + 4 + 124)
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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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