1450 lines
40 KiB
C
1450 lines
40 KiB
C
/*
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* Copyright (C) 2016 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 Server Side
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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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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "nbd-internal.h"
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static int system_errno_to_nbd_errno(int err)
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{
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switch (err) {
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case 0:
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return NBD_SUCCESS;
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case EPERM:
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case EROFS:
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return NBD_EPERM;
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case EIO:
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return NBD_EIO;
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case ENOMEM:
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return NBD_ENOMEM;
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#ifdef EDQUOT
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case EDQUOT:
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#endif
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case EFBIG:
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case ENOSPC:
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return NBD_ENOSPC;
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case ESHUTDOWN:
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return NBD_ESHUTDOWN;
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case EINVAL:
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default:
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return NBD_EINVAL;
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}
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}
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/* Definitions for opaque data types */
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typedef struct NBDRequestData NBDRequestData;
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struct NBDRequestData {
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QSIMPLEQ_ENTRY(NBDRequestData) entry;
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NBDClient *client;
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uint8_t *data;
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bool complete;
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};
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struct NBDExport {
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int refcount;
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void (*close)(NBDExport *exp);
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BlockBackend *blk;
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char *name;
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char *description;
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off_t dev_offset;
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off_t size;
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uint16_t nbdflags;
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QTAILQ_HEAD(, NBDClient) clients;
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QTAILQ_ENTRY(NBDExport) next;
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AioContext *ctx;
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BlockBackend *eject_notifier_blk;
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Notifier eject_notifier;
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};
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static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
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struct NBDClient {
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int refcount;
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void (*close)(NBDClient *client);
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bool no_zeroes;
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NBDExport *exp;
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QCryptoTLSCreds *tlscreds;
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char *tlsaclname;
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QIOChannelSocket *sioc; /* The underlying data channel */
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QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
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Coroutine *recv_coroutine;
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CoMutex send_lock;
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Coroutine *send_coroutine;
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bool can_read;
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QTAILQ_ENTRY(NBDClient) next;
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int nb_requests;
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bool closing;
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};
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/* That's all folks */
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static void nbd_set_handlers(NBDClient *client);
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static void nbd_unset_handlers(NBDClient *client);
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static void nbd_update_can_read(NBDClient *client);
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static gboolean nbd_negotiate_continue(QIOChannel *ioc,
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GIOCondition condition,
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void *opaque)
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{
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qemu_coroutine_enter(opaque);
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return TRUE;
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}
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static ssize_t nbd_negotiate_read(QIOChannel *ioc, void *buffer, size_t size)
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{
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ssize_t ret;
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guint watch;
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assert(qemu_in_coroutine());
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/* Negotiation are always in main loop. */
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watch = qio_channel_add_watch(ioc,
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G_IO_IN,
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nbd_negotiate_continue,
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qemu_coroutine_self(),
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NULL);
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ret = read_sync(ioc, buffer, size);
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g_source_remove(watch);
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return ret;
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}
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static ssize_t nbd_negotiate_write(QIOChannel *ioc, const void *buffer,
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size_t size)
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{
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ssize_t ret;
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guint watch;
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assert(qemu_in_coroutine());
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/* Negotiation are always in main loop. */
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watch = qio_channel_add_watch(ioc,
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G_IO_OUT,
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nbd_negotiate_continue,
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qemu_coroutine_self(),
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NULL);
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ret = write_sync(ioc, buffer, size);
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g_source_remove(watch);
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return ret;
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}
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static ssize_t nbd_negotiate_drop_sync(QIOChannel *ioc, size_t size)
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{
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ssize_t ret, dropped = size;
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uint8_t *buffer = g_malloc(MIN(65536, size));
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while (size > 0) {
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ret = nbd_negotiate_read(ioc, buffer, MIN(65536, size));
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if (ret < 0) {
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g_free(buffer);
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return ret;
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}
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assert(ret <= size);
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size -= ret;
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}
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g_free(buffer);
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return dropped;
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}
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/* Basic flow for negotiation
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Server Client
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Negotiate
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or
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Server Client
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Negotiate #1
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Option
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Negotiate #2
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----
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followed by
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Server Client
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Request
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Response
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Request
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Response
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...
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...
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Request (type == 2)
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*/
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/* Send a reply header, including length, but no payload.
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* Return -errno on error, 0 on success. */
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static int nbd_negotiate_send_rep_len(QIOChannel *ioc, uint32_t type,
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uint32_t opt, uint32_t len)
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{
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uint64_t magic;
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TRACE("Reply opt=%" PRIx32 " type=%" PRIx32 " len=%" PRIu32,
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type, opt, len);
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magic = cpu_to_be64(NBD_REP_MAGIC);
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if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
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LOG("write failed (rep magic)");
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return -EINVAL;
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}
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opt = cpu_to_be32(opt);
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if (nbd_negotiate_write(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
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LOG("write failed (rep opt)");
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return -EINVAL;
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}
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type = cpu_to_be32(type);
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if (nbd_negotiate_write(ioc, &type, sizeof(type)) != sizeof(type)) {
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LOG("write failed (rep type)");
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return -EINVAL;
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}
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len = cpu_to_be32(len);
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if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
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LOG("write failed (rep data length)");
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return -EINVAL;
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}
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return 0;
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}
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/* Send a reply header with default 0 length.
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* Return -errno on error, 0 on success. */
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static int nbd_negotiate_send_rep(QIOChannel *ioc, uint32_t type, uint32_t opt)
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{
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return nbd_negotiate_send_rep_len(ioc, type, opt, 0);
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}
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/* Send an error reply.
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* Return -errno on error, 0 on success. */
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static int GCC_FMT_ATTR(4, 5)
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nbd_negotiate_send_rep_err(QIOChannel *ioc, uint32_t type,
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uint32_t opt, const char *fmt, ...)
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{
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va_list va;
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char *msg;
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int ret;
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size_t len;
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va_start(va, fmt);
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msg = g_strdup_vprintf(fmt, va);
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va_end(va);
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len = strlen(msg);
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assert(len < 4096);
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TRACE("sending error message \"%s\"", msg);
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ret = nbd_negotiate_send_rep_len(ioc, type, opt, len);
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if (ret < 0) {
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goto out;
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}
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if (nbd_negotiate_write(ioc, msg, len) != len) {
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LOG("write failed (error message)");
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ret = -EIO;
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} else {
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ret = 0;
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}
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out:
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g_free(msg);
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return ret;
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}
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/* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload.
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* Return -errno on error, 0 on success. */
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static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
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{
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size_t name_len, desc_len;
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uint32_t len;
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const char *name = exp->name ? exp->name : "";
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const char *desc = exp->description ? exp->description : "";
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int rc;
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TRACE("Advertising export name '%s' description '%s'", name, desc);
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name_len = strlen(name);
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desc_len = strlen(desc);
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len = name_len + desc_len + sizeof(len);
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rc = nbd_negotiate_send_rep_len(ioc, NBD_REP_SERVER, NBD_OPT_LIST, len);
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if (rc < 0) {
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return rc;
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}
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len = cpu_to_be32(name_len);
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if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
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LOG("write failed (name length)");
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return -EINVAL;
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}
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if (nbd_negotiate_write(ioc, name, name_len) != name_len) {
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LOG("write failed (name buffer)");
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return -EINVAL;
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}
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if (nbd_negotiate_write(ioc, desc, desc_len) != desc_len) {
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LOG("write failed (description buffer)");
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return -EINVAL;
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}
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return 0;
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}
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/* Process the NBD_OPT_LIST command, with a potential series of replies.
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* Return -errno on error, 0 on success. */
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static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length)
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{
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NBDExport *exp;
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if (length) {
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if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
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return -EIO;
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}
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return nbd_negotiate_send_rep_err(client->ioc,
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NBD_REP_ERR_INVALID, NBD_OPT_LIST,
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"OPT_LIST should not have length");
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}
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/* For each export, send a NBD_REP_SERVER reply. */
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QTAILQ_FOREACH(exp, &exports, next) {
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if (nbd_negotiate_send_rep_list(client->ioc, exp)) {
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return -EINVAL;
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}
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}
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/* Finish with a NBD_REP_ACK. */
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return nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, NBD_OPT_LIST);
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}
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static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length)
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{
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int rc = -EINVAL;
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char name[NBD_MAX_NAME_SIZE + 1];
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/* Client sends:
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[20 .. xx] export name (length bytes)
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*/
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TRACE("Checking length");
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if (length >= sizeof(name)) {
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LOG("Bad length received");
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goto fail;
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}
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if (nbd_negotiate_read(client->ioc, name, length) != length) {
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LOG("read failed");
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goto fail;
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}
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name[length] = '\0';
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TRACE("Client requested export '%s'", name);
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client->exp = nbd_export_find(name);
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if (!client->exp) {
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LOG("export not found");
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goto fail;
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}
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QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
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nbd_export_get(client->exp);
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rc = 0;
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fail:
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return rc;
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}
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/* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
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* new channel for all further (now-encrypted) communication. */
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static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
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uint32_t length)
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{
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QIOChannel *ioc;
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QIOChannelTLS *tioc;
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struct NBDTLSHandshakeData data = { 0 };
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TRACE("Setting up TLS");
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ioc = client->ioc;
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if (length) {
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if (nbd_negotiate_drop_sync(ioc, length) != length) {
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return NULL;
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}
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nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
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"OPT_STARTTLS should not have length");
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return NULL;
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}
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if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
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NBD_OPT_STARTTLS) < 0) {
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return NULL;
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}
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tioc = qio_channel_tls_new_server(ioc,
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client->tlscreds,
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client->tlsaclname,
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NULL);
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if (!tioc) {
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return NULL;
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}
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qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls");
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TRACE("Starting TLS handshake");
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data.loop = g_main_loop_new(g_main_context_default(), FALSE);
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qio_channel_tls_handshake(tioc,
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nbd_tls_handshake,
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&data,
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NULL);
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if (!data.complete) {
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g_main_loop_run(data.loop);
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}
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g_main_loop_unref(data.loop);
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if (data.error) {
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object_unref(OBJECT(tioc));
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error_free(data.error);
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return NULL;
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}
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return QIO_CHANNEL(tioc);
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}
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|
|
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/* Process all NBD_OPT_* client option commands.
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* Return -errno on error, 0 on success. */
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static int nbd_negotiate_options(NBDClient *client)
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{
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uint32_t flags;
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bool fixedNewstyle = false;
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/* Client sends:
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[ 0 .. 3] client flags
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[ 0 .. 7] NBD_OPTS_MAGIC
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[ 8 .. 11] NBD option
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[12 .. 15] Data length
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... Rest of request
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|
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[ 0 .. 7] NBD_OPTS_MAGIC
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[ 8 .. 11] Second NBD option
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[12 .. 15] Data length
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... Rest of request
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*/
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if (nbd_negotiate_read(client->ioc, &flags, sizeof(flags)) !=
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sizeof(flags)) {
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LOG("read failed");
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return -EIO;
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}
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TRACE("Checking client flags");
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be32_to_cpus(&flags);
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if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
|
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TRACE("Client supports fixed newstyle handshake");
|
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fixedNewstyle = true;
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flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
|
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}
|
|
if (flags & NBD_FLAG_C_NO_ZEROES) {
|
|
TRACE("Client supports no zeroes at handshake end");
|
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client->no_zeroes = true;
|
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flags &= ~NBD_FLAG_C_NO_ZEROES;
|
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}
|
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if (flags != 0) {
|
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TRACE("Unknown client flags 0x%" PRIx32 " received", flags);
|
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return -EIO;
|
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}
|
|
|
|
while (1) {
|
|
int ret;
|
|
uint32_t clientflags, length;
|
|
uint64_t magic;
|
|
|
|
if (nbd_negotiate_read(client->ioc, &magic, sizeof(magic)) !=
|
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sizeof(magic)) {
|
|
LOG("read failed");
|
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return -EINVAL;
|
|
}
|
|
TRACE("Checking opts magic");
|
|
if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {
|
|
LOG("Bad magic received");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (nbd_negotiate_read(client->ioc, &clientflags,
|
|
sizeof(clientflags)) != sizeof(clientflags)) {
|
|
LOG("read failed");
|
|
return -EINVAL;
|
|
}
|
|
clientflags = be32_to_cpu(clientflags);
|
|
|
|
if (nbd_negotiate_read(client->ioc, &length, sizeof(length)) !=
|
|
sizeof(length)) {
|
|
LOG("read failed");
|
|
return -EINVAL;
|
|
}
|
|
length = be32_to_cpu(length);
|
|
|
|
TRACE("Checking option 0x%" PRIx32, clientflags);
|
|
if (client->tlscreds &&
|
|
client->ioc == (QIOChannel *)client->sioc) {
|
|
QIOChannel *tioc;
|
|
if (!fixedNewstyle) {
|
|
TRACE("Unsupported option 0x%" PRIx32, clientflags);
|
|
return -EINVAL;
|
|
}
|
|
switch (clientflags) {
|
|
case NBD_OPT_STARTTLS:
|
|
tioc = nbd_negotiate_handle_starttls(client, length);
|
|
if (!tioc) {
|
|
return -EIO;
|
|
}
|
|
object_unref(OBJECT(client->ioc));
|
|
client->ioc = QIO_CHANNEL(tioc);
|
|
break;
|
|
|
|
case NBD_OPT_EXPORT_NAME:
|
|
/* No way to return an error to client, so drop connection */
|
|
TRACE("Option 0x%x not permitted before TLS", clientflags);
|
|
return -EINVAL;
|
|
|
|
default:
|
|
if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
|
|
return -EIO;
|
|
}
|
|
ret = nbd_negotiate_send_rep_err(client->ioc,
|
|
NBD_REP_ERR_TLS_REQD,
|
|
clientflags,
|
|
"Option 0x%" PRIx32
|
|
"not permitted before TLS",
|
|
clientflags);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
/* Let the client keep trying, unless they asked to quit */
|
|
if (clientflags == NBD_OPT_ABORT) {
|
|
return -EINVAL;
|
|
}
|
|
break;
|
|
}
|
|
} else if (fixedNewstyle) {
|
|
switch (clientflags) {
|
|
case NBD_OPT_LIST:
|
|
ret = nbd_negotiate_handle_list(client, length);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
break;
|
|
|
|
case NBD_OPT_ABORT:
|
|
/* NBD spec says we must try to reply before
|
|
* disconnecting, but that we must also tolerate
|
|
* guests that don't wait for our reply. */
|
|
nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK, clientflags);
|
|
return -EINVAL;
|
|
|
|
case NBD_OPT_EXPORT_NAME:
|
|
return nbd_negotiate_handle_export_name(client, length);
|
|
|
|
case NBD_OPT_STARTTLS:
|
|
if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
|
|
return -EIO;
|
|
}
|
|
if (client->tlscreds) {
|
|
ret = nbd_negotiate_send_rep_err(client->ioc,
|
|
NBD_REP_ERR_INVALID,
|
|
clientflags,
|
|
"TLS already enabled");
|
|
} else {
|
|
ret = nbd_negotiate_send_rep_err(client->ioc,
|
|
NBD_REP_ERR_POLICY,
|
|
clientflags,
|
|
"TLS not configured");
|
|
}
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
break;
|
|
default:
|
|
if (nbd_negotiate_drop_sync(client->ioc, length) != length) {
|
|
return -EIO;
|
|
}
|
|
ret = nbd_negotiate_send_rep_err(client->ioc,
|
|
NBD_REP_ERR_UNSUP,
|
|
clientflags,
|
|
"Unsupported option 0x%"
|
|
PRIx32,
|
|
clientflags);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
break;
|
|
}
|
|
} else {
|
|
/*
|
|
* If broken new-style we should drop the connection
|
|
* for anything except NBD_OPT_EXPORT_NAME
|
|
*/
|
|
switch (clientflags) {
|
|
case NBD_OPT_EXPORT_NAME:
|
|
return nbd_negotiate_handle_export_name(client, length);
|
|
|
|
default:
|
|
TRACE("Unsupported option 0x%" PRIx32, clientflags);
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
typedef struct {
|
|
NBDClient *client;
|
|
Coroutine *co;
|
|
} NBDClientNewData;
|
|
|
|
static coroutine_fn int nbd_negotiate(NBDClientNewData *data)
|
|
{
|
|
NBDClient *client = data->client;
|
|
char buf[8 + 8 + 8 + 128];
|
|
int rc;
|
|
const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
|
|
NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
|
|
NBD_FLAG_SEND_WRITE_ZEROES);
|
|
bool oldStyle;
|
|
size_t len;
|
|
|
|
/* Old style negotiation header without options
|
|
[ 0 .. 7] passwd ("NBDMAGIC")
|
|
[ 8 .. 15] magic (NBD_CLIENT_MAGIC)
|
|
[16 .. 23] size
|
|
[24 .. 25] server flags (0)
|
|
[26 .. 27] export flags
|
|
[28 .. 151] reserved (0)
|
|
|
|
New style negotiation header with options
|
|
[ 0 .. 7] passwd ("NBDMAGIC")
|
|
[ 8 .. 15] magic (NBD_OPTS_MAGIC)
|
|
[16 .. 17] server flags (0)
|
|
....options sent....
|
|
[18 .. 25] size
|
|
[26 .. 27] export flags
|
|
[28 .. 151] reserved (0, omit if no_zeroes)
|
|
*/
|
|
|
|
qio_channel_set_blocking(client->ioc, false, NULL);
|
|
rc = -EINVAL;
|
|
|
|
TRACE("Beginning negotiation.");
|
|
memset(buf, 0, sizeof(buf));
|
|
memcpy(buf, "NBDMAGIC", 8);
|
|
|
|
oldStyle = client->exp != NULL && !client->tlscreds;
|
|
if (oldStyle) {
|
|
TRACE("advertising size %" PRIu64 " and flags %x",
|
|
client->exp->size, client->exp->nbdflags | myflags);
|
|
stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
|
|
stq_be_p(buf + 16, client->exp->size);
|
|
stw_be_p(buf + 26, client->exp->nbdflags | myflags);
|
|
} else {
|
|
stq_be_p(buf + 8, NBD_OPTS_MAGIC);
|
|
stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES);
|
|
}
|
|
|
|
if (oldStyle) {
|
|
if (client->tlscreds) {
|
|
TRACE("TLS cannot be enabled with oldstyle protocol");
|
|
goto fail;
|
|
}
|
|
if (nbd_negotiate_write(client->ioc, buf, sizeof(buf)) != sizeof(buf)) {
|
|
LOG("write failed");
|
|
goto fail;
|
|
}
|
|
} else {
|
|
if (nbd_negotiate_write(client->ioc, buf, 18) != 18) {
|
|
LOG("write failed");
|
|
goto fail;
|
|
}
|
|
rc = nbd_negotiate_options(client);
|
|
if (rc != 0) {
|
|
LOG("option negotiation failed");
|
|
goto fail;
|
|
}
|
|
|
|
TRACE("advertising size %" PRIu64 " and flags %x",
|
|
client->exp->size, client->exp->nbdflags | myflags);
|
|
stq_be_p(buf + 18, client->exp->size);
|
|
stw_be_p(buf + 26, client->exp->nbdflags | myflags);
|
|
len = client->no_zeroes ? 10 : sizeof(buf) - 18;
|
|
if (nbd_negotiate_write(client->ioc, buf + 18, len) != len) {
|
|
LOG("write failed");
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
TRACE("Negotiation succeeded.");
|
|
rc = 0;
|
|
fail:
|
|
return rc;
|
|
}
|
|
|
|
static ssize_t nbd_receive_request(QIOChannel *ioc, NBDRequest *request)
|
|
{
|
|
uint8_t buf[NBD_REQUEST_SIZE];
|
|
uint32_t magic;
|
|
ssize_t ret;
|
|
|
|
ret = read_sync(ioc, buf, sizeof(buf));
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
if (ret != sizeof(buf)) {
|
|
LOG("read failed");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Request
|
|
[ 0 .. 3] magic (NBD_REQUEST_MAGIC)
|
|
[ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...)
|
|
[ 6 .. 7] type (NBD_CMD_READ, ...)
|
|
[ 8 .. 15] handle
|
|
[16 .. 23] from
|
|
[24 .. 27] len
|
|
*/
|
|
|
|
magic = ldl_be_p(buf);
|
|
request->flags = lduw_be_p(buf + 4);
|
|
request->type = lduw_be_p(buf + 6);
|
|
request->handle = ldq_be_p(buf + 8);
|
|
request->from = ldq_be_p(buf + 16);
|
|
request->len = ldl_be_p(buf + 24);
|
|
|
|
TRACE("Got request: { magic = 0x%" PRIx32 ", .flags = %" PRIx16
|
|
", .type = %" PRIx16 ", from = %" PRIu64 ", len = %" PRIu32 " }",
|
|
magic, request->flags, request->type, request->from, request->len);
|
|
|
|
if (magic != NBD_REQUEST_MAGIC) {
|
|
LOG("invalid magic (got 0x%" PRIx32 ")", magic);
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t nbd_send_reply(QIOChannel *ioc, NBDReply *reply)
|
|
{
|
|
uint8_t buf[NBD_REPLY_SIZE];
|
|
ssize_t ret;
|
|
|
|
reply->error = system_errno_to_nbd_errno(reply->error);
|
|
|
|
TRACE("Sending response to client: { .error = %" PRId32
|
|
", handle = %" PRIu64 " }",
|
|
reply->error, reply->handle);
|
|
|
|
/* Reply
|
|
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
|
|
[ 4 .. 7] error (0 == no error)
|
|
[ 7 .. 15] handle
|
|
*/
|
|
stl_be_p(buf, NBD_REPLY_MAGIC);
|
|
stl_be_p(buf + 4, reply->error);
|
|
stq_be_p(buf + 8, reply->handle);
|
|
|
|
ret = write_sync(ioc, buf, sizeof(buf));
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
if (ret != sizeof(buf)) {
|
|
LOG("writing to socket failed");
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#define MAX_NBD_REQUESTS 16
|
|
|
|
void nbd_client_get(NBDClient *client)
|
|
{
|
|
client->refcount++;
|
|
}
|
|
|
|
void nbd_client_put(NBDClient *client)
|
|
{
|
|
if (--client->refcount == 0) {
|
|
/* The last reference should be dropped by client->close,
|
|
* which is called by client_close.
|
|
*/
|
|
assert(client->closing);
|
|
|
|
nbd_unset_handlers(client);
|
|
object_unref(OBJECT(client->sioc));
|
|
object_unref(OBJECT(client->ioc));
|
|
if (client->tlscreds) {
|
|
object_unref(OBJECT(client->tlscreds));
|
|
}
|
|
g_free(client->tlsaclname);
|
|
if (client->exp) {
|
|
QTAILQ_REMOVE(&client->exp->clients, client, next);
|
|
nbd_export_put(client->exp);
|
|
}
|
|
g_free(client);
|
|
}
|
|
}
|
|
|
|
static void client_close(NBDClient *client)
|
|
{
|
|
if (client->closing) {
|
|
return;
|
|
}
|
|
|
|
client->closing = true;
|
|
|
|
/* Force requests to finish. They will drop their own references,
|
|
* then we'll close the socket and free the NBDClient.
|
|
*/
|
|
qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
|
|
NULL);
|
|
|
|
/* Also tell the client, so that they release their reference. */
|
|
if (client->close) {
|
|
client->close(client);
|
|
}
|
|
}
|
|
|
|
static NBDRequestData *nbd_request_get(NBDClient *client)
|
|
{
|
|
NBDRequestData *req;
|
|
|
|
assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
|
|
client->nb_requests++;
|
|
nbd_update_can_read(client);
|
|
|
|
req = g_new0(NBDRequestData, 1);
|
|
nbd_client_get(client);
|
|
req->client = client;
|
|
return req;
|
|
}
|
|
|
|
static void nbd_request_put(NBDRequestData *req)
|
|
{
|
|
NBDClient *client = req->client;
|
|
|
|
if (req->data) {
|
|
qemu_vfree(req->data);
|
|
}
|
|
g_free(req);
|
|
|
|
client->nb_requests--;
|
|
nbd_update_can_read(client);
|
|
nbd_client_put(client);
|
|
}
|
|
|
|
static void blk_aio_attached(AioContext *ctx, void *opaque)
|
|
{
|
|
NBDExport *exp = opaque;
|
|
NBDClient *client;
|
|
|
|
TRACE("Export %s: Attaching clients to AIO context %p\n", exp->name, ctx);
|
|
|
|
exp->ctx = ctx;
|
|
|
|
QTAILQ_FOREACH(client, &exp->clients, next) {
|
|
nbd_set_handlers(client);
|
|
}
|
|
}
|
|
|
|
static void blk_aio_detach(void *opaque)
|
|
{
|
|
NBDExport *exp = opaque;
|
|
NBDClient *client;
|
|
|
|
TRACE("Export %s: Detaching clients from AIO context %p\n", exp->name, exp->ctx);
|
|
|
|
QTAILQ_FOREACH(client, &exp->clients, next) {
|
|
nbd_unset_handlers(client);
|
|
}
|
|
|
|
exp->ctx = NULL;
|
|
}
|
|
|
|
static void nbd_eject_notifier(Notifier *n, void *data)
|
|
{
|
|
NBDExport *exp = container_of(n, NBDExport, eject_notifier);
|
|
nbd_export_close(exp);
|
|
}
|
|
|
|
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)
|
|
{
|
|
BlockBackend *blk;
|
|
NBDExport *exp = g_malloc0(sizeof(NBDExport));
|
|
|
|
blk = blk_new();
|
|
blk_insert_bs(blk, bs);
|
|
blk_set_enable_write_cache(blk, !writethrough);
|
|
|
|
exp->refcount = 1;
|
|
QTAILQ_INIT(&exp->clients);
|
|
exp->blk = blk;
|
|
exp->dev_offset = dev_offset;
|
|
exp->nbdflags = nbdflags;
|
|
exp->size = size < 0 ? blk_getlength(blk) : size;
|
|
if (exp->size < 0) {
|
|
error_setg_errno(errp, -exp->size,
|
|
"Failed to determine the NBD export's length");
|
|
goto fail;
|
|
}
|
|
exp->size -= exp->size % BDRV_SECTOR_SIZE;
|
|
|
|
exp->close = close;
|
|
exp->ctx = blk_get_aio_context(blk);
|
|
blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
|
|
|
|
if (on_eject_blk) {
|
|
blk_ref(on_eject_blk);
|
|
exp->eject_notifier_blk = on_eject_blk;
|
|
exp->eject_notifier.notify = nbd_eject_notifier;
|
|
blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
|
|
}
|
|
|
|
/*
|
|
* NBD exports are used for non-shared storage migration. Make sure
|
|
* that BDRV_O_INACTIVE is cleared and the image is ready for write
|
|
* access since the export could be available before migration handover.
|
|
*/
|
|
aio_context_acquire(exp->ctx);
|
|
blk_invalidate_cache(blk, NULL);
|
|
aio_context_release(exp->ctx);
|
|
return exp;
|
|
|
|
fail:
|
|
blk_unref(blk);
|
|
g_free(exp);
|
|
return NULL;
|
|
}
|
|
|
|
NBDExport *nbd_export_find(const char *name)
|
|
{
|
|
NBDExport *exp;
|
|
QTAILQ_FOREACH(exp, &exports, next) {
|
|
if (strcmp(name, exp->name) == 0) {
|
|
return exp;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
void nbd_export_set_name(NBDExport *exp, const char *name)
|
|
{
|
|
if (exp->name == name) {
|
|
return;
|
|
}
|
|
|
|
nbd_export_get(exp);
|
|
if (exp->name != NULL) {
|
|
g_free(exp->name);
|
|
exp->name = NULL;
|
|
QTAILQ_REMOVE(&exports, exp, next);
|
|
nbd_export_put(exp);
|
|
}
|
|
if (name != NULL) {
|
|
nbd_export_get(exp);
|
|
exp->name = g_strdup(name);
|
|
QTAILQ_INSERT_TAIL(&exports, exp, next);
|
|
}
|
|
nbd_export_put(exp);
|
|
}
|
|
|
|
void nbd_export_set_description(NBDExport *exp, const char *description)
|
|
{
|
|
g_free(exp->description);
|
|
exp->description = g_strdup(description);
|
|
}
|
|
|
|
void nbd_export_close(NBDExport *exp)
|
|
{
|
|
NBDClient *client, *next;
|
|
|
|
nbd_export_get(exp);
|
|
QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {
|
|
client_close(client);
|
|
}
|
|
nbd_export_set_name(exp, NULL);
|
|
nbd_export_set_description(exp, NULL);
|
|
nbd_export_put(exp);
|
|
}
|
|
|
|
void nbd_export_get(NBDExport *exp)
|
|
{
|
|
assert(exp->refcount > 0);
|
|
exp->refcount++;
|
|
}
|
|
|
|
void nbd_export_put(NBDExport *exp)
|
|
{
|
|
assert(exp->refcount > 0);
|
|
if (exp->refcount == 1) {
|
|
nbd_export_close(exp);
|
|
}
|
|
|
|
if (--exp->refcount == 0) {
|
|
assert(exp->name == NULL);
|
|
assert(exp->description == NULL);
|
|
|
|
if (exp->close) {
|
|
exp->close(exp);
|
|
}
|
|
|
|
if (exp->blk) {
|
|
if (exp->eject_notifier_blk) {
|
|
notifier_remove(&exp->eject_notifier);
|
|
blk_unref(exp->eject_notifier_blk);
|
|
}
|
|
blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
|
|
blk_aio_detach, exp);
|
|
blk_unref(exp->blk);
|
|
exp->blk = NULL;
|
|
}
|
|
|
|
g_free(exp);
|
|
}
|
|
}
|
|
|
|
BlockBackend *nbd_export_get_blockdev(NBDExport *exp)
|
|
{
|
|
return exp->blk;
|
|
}
|
|
|
|
void nbd_export_close_all(void)
|
|
{
|
|
NBDExport *exp, *next;
|
|
|
|
QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {
|
|
nbd_export_close(exp);
|
|
}
|
|
}
|
|
|
|
static ssize_t nbd_co_send_reply(NBDRequestData *req, NBDReply *reply,
|
|
int len)
|
|
{
|
|
NBDClient *client = req->client;
|
|
ssize_t rc, ret;
|
|
|
|
g_assert(qemu_in_coroutine());
|
|
qemu_co_mutex_lock(&client->send_lock);
|
|
client->send_coroutine = qemu_coroutine_self();
|
|
nbd_set_handlers(client);
|
|
|
|
if (!len) {
|
|
rc = nbd_send_reply(client->ioc, reply);
|
|
} else {
|
|
qio_channel_set_cork(client->ioc, true);
|
|
rc = nbd_send_reply(client->ioc, reply);
|
|
if (rc >= 0) {
|
|
ret = write_sync(client->ioc, req->data, len);
|
|
if (ret != len) {
|
|
rc = -EIO;
|
|
}
|
|
}
|
|
qio_channel_set_cork(client->ioc, false);
|
|
}
|
|
|
|
client->send_coroutine = NULL;
|
|
nbd_set_handlers(client);
|
|
qemu_co_mutex_unlock(&client->send_lock);
|
|
return rc;
|
|
}
|
|
|
|
/* Collect a client request. Return 0 if request looks valid, -EAGAIN
|
|
* to keep trying the collection, -EIO to drop connection right away,
|
|
* and any other negative value to report an error to the client
|
|
* (although the caller may still need to disconnect after reporting
|
|
* the error). */
|
|
static ssize_t nbd_co_receive_request(NBDRequestData *req,
|
|
NBDRequest *request)
|
|
{
|
|
NBDClient *client = req->client;
|
|
ssize_t rc;
|
|
|
|
g_assert(qemu_in_coroutine());
|
|
client->recv_coroutine = qemu_coroutine_self();
|
|
nbd_update_can_read(client);
|
|
|
|
rc = nbd_receive_request(client->ioc, request);
|
|
if (rc < 0) {
|
|
if (rc != -EAGAIN) {
|
|
rc = -EIO;
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
TRACE("Decoding type");
|
|
|
|
if (request->type != NBD_CMD_WRITE) {
|
|
/* No payload, we are ready to read the next request. */
|
|
req->complete = true;
|
|
}
|
|
|
|
if (request->type == NBD_CMD_DISC) {
|
|
/* Special case: we're going to disconnect without a reply,
|
|
* whether or not flags, from, or len are bogus */
|
|
TRACE("Request type is DISCONNECT");
|
|
rc = -EIO;
|
|
goto out;
|
|
}
|
|
|
|
/* Check for sanity in the parameters, part 1. Defer as many
|
|
* checks as possible until after reading any NBD_CMD_WRITE
|
|
* payload, so we can try and keep the connection alive. */
|
|
if ((request->from + request->len) < request->from) {
|
|
LOG("integer overflow detected, you're probably being attacked");
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE) {
|
|
if (request->len > NBD_MAX_BUFFER_SIZE) {
|
|
LOG("len (%" PRIu32" ) is larger than max len (%u)",
|
|
request->len, NBD_MAX_BUFFER_SIZE);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
req->data = blk_try_blockalign(client->exp->blk, request->len);
|
|
if (req->data == NULL) {
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
}
|
|
if (request->type == NBD_CMD_WRITE) {
|
|
TRACE("Reading %" PRIu32 " byte(s)", request->len);
|
|
|
|
if (read_sync(client->ioc, req->data, request->len) != request->len) {
|
|
LOG("reading from socket failed");
|
|
rc = -EIO;
|
|
goto out;
|
|
}
|
|
req->complete = true;
|
|
}
|
|
|
|
/* Sanity checks, part 2. */
|
|
if (request->from + request->len > client->exp->size) {
|
|
LOG("operation past EOF; From: %" PRIu64 ", Len: %" PRIu32
|
|
", Size: %" PRIu64, request->from, request->len,
|
|
(uint64_t)client->exp->size);
|
|
rc = request->type == NBD_CMD_WRITE ? -ENOSPC : -EINVAL;
|
|
goto out;
|
|
}
|
|
if (request->flags & ~(NBD_CMD_FLAG_FUA | NBD_CMD_FLAG_NO_HOLE)) {
|
|
LOG("unsupported flags (got 0x%x)", request->flags);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
if (request->type != NBD_CMD_WRITE_ZEROES &&
|
|
(request->flags & NBD_CMD_FLAG_NO_HOLE)) {
|
|
LOG("unexpected flags (got 0x%x)", request->flags);
|
|
rc = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
rc = 0;
|
|
|
|
out:
|
|
client->recv_coroutine = NULL;
|
|
nbd_update_can_read(client);
|
|
|
|
return rc;
|
|
}
|
|
|
|
static void nbd_trip(void *opaque)
|
|
{
|
|
NBDClient *client = opaque;
|
|
NBDExport *exp = client->exp;
|
|
NBDRequestData *req;
|
|
NBDRequest request;
|
|
NBDReply reply;
|
|
ssize_t ret;
|
|
int flags;
|
|
|
|
TRACE("Reading request.");
|
|
if (client->closing) {
|
|
return;
|
|
}
|
|
|
|
req = nbd_request_get(client);
|
|
ret = nbd_co_receive_request(req, &request);
|
|
if (ret == -EAGAIN) {
|
|
goto done;
|
|
}
|
|
if (ret == -EIO) {
|
|
goto out;
|
|
}
|
|
|
|
reply.handle = request.handle;
|
|
reply.error = 0;
|
|
|
|
if (ret < 0) {
|
|
reply.error = -ret;
|
|
goto error_reply;
|
|
}
|
|
|
|
if (client->closing) {
|
|
/*
|
|
* The client may be closed when we are blocked in
|
|
* nbd_co_receive_request()
|
|
*/
|
|
goto done;
|
|
}
|
|
|
|
switch (request.type) {
|
|
case NBD_CMD_READ:
|
|
TRACE("Request type is READ");
|
|
|
|
/* XXX: NBD Protocol only documents use of FUA with WRITE */
|
|
if (request.flags & NBD_CMD_FLAG_FUA) {
|
|
ret = blk_co_flush(exp->blk);
|
|
if (ret < 0) {
|
|
LOG("flush failed");
|
|
reply.error = -ret;
|
|
goto error_reply;
|
|
}
|
|
}
|
|
|
|
ret = blk_pread(exp->blk, request.from + exp->dev_offset,
|
|
req->data, request.len);
|
|
if (ret < 0) {
|
|
LOG("reading from file failed");
|
|
reply.error = -ret;
|
|
goto error_reply;
|
|
}
|
|
|
|
TRACE("Read %" PRIu32" byte(s)", request.len);
|
|
if (nbd_co_send_reply(req, &reply, request.len) < 0)
|
|
goto out;
|
|
break;
|
|
case NBD_CMD_WRITE:
|
|
TRACE("Request type is WRITE");
|
|
|
|
if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
|
|
TRACE("Server is read-only, return error");
|
|
reply.error = EROFS;
|
|
goto error_reply;
|
|
}
|
|
|
|
TRACE("Writing to device");
|
|
|
|
flags = 0;
|
|
if (request.flags & NBD_CMD_FLAG_FUA) {
|
|
flags |= BDRV_REQ_FUA;
|
|
}
|
|
ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
|
|
req->data, request.len, flags);
|
|
if (ret < 0) {
|
|
LOG("writing to file failed");
|
|
reply.error = -ret;
|
|
goto error_reply;
|
|
}
|
|
|
|
if (nbd_co_send_reply(req, &reply, 0) < 0) {
|
|
goto out;
|
|
}
|
|
break;
|
|
|
|
case NBD_CMD_WRITE_ZEROES:
|
|
TRACE("Request type is WRITE_ZEROES");
|
|
|
|
if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
|
|
TRACE("Server is read-only, return error");
|
|
reply.error = EROFS;
|
|
goto error_reply;
|
|
}
|
|
|
|
TRACE("Writing to device");
|
|
|
|
flags = 0;
|
|
if (request.flags & NBD_CMD_FLAG_FUA) {
|
|
flags |= BDRV_REQ_FUA;
|
|
}
|
|
if (!(request.flags & NBD_CMD_FLAG_NO_HOLE)) {
|
|
flags |= BDRV_REQ_MAY_UNMAP;
|
|
}
|
|
ret = blk_pwrite_zeroes(exp->blk, request.from + exp->dev_offset,
|
|
request.len, flags);
|
|
if (ret < 0) {
|
|
LOG("writing to file failed");
|
|
reply.error = -ret;
|
|
goto error_reply;
|
|
}
|
|
|
|
if (nbd_co_send_reply(req, &reply, 0) < 0) {
|
|
goto out;
|
|
}
|
|
break;
|
|
|
|
case NBD_CMD_DISC:
|
|
/* unreachable, thanks to special case in nbd_co_receive_request() */
|
|
abort();
|
|
|
|
case NBD_CMD_FLUSH:
|
|
TRACE("Request type is FLUSH");
|
|
|
|
ret = blk_co_flush(exp->blk);
|
|
if (ret < 0) {
|
|
LOG("flush failed");
|
|
reply.error = -ret;
|
|
}
|
|
if (nbd_co_send_reply(req, &reply, 0) < 0) {
|
|
goto out;
|
|
}
|
|
break;
|
|
case NBD_CMD_TRIM:
|
|
TRACE("Request type is TRIM");
|
|
ret = blk_co_pdiscard(exp->blk, request.from + exp->dev_offset,
|
|
request.len);
|
|
if (ret < 0) {
|
|
LOG("discard failed");
|
|
reply.error = -ret;
|
|
}
|
|
if (nbd_co_send_reply(req, &reply, 0) < 0) {
|
|
goto out;
|
|
}
|
|
break;
|
|
default:
|
|
LOG("invalid request type (%" PRIu32 ") received", request.type);
|
|
reply.error = EINVAL;
|
|
error_reply:
|
|
/* We must disconnect after NBD_CMD_WRITE if we did not
|
|
* read the payload.
|
|
*/
|
|
if (nbd_co_send_reply(req, &reply, 0) < 0 || !req->complete) {
|
|
goto out;
|
|
}
|
|
break;
|
|
}
|
|
|
|
TRACE("Request/Reply complete");
|
|
|
|
done:
|
|
nbd_request_put(req);
|
|
return;
|
|
|
|
out:
|
|
nbd_request_put(req);
|
|
client_close(client);
|
|
}
|
|
|
|
static void nbd_read(void *opaque)
|
|
{
|
|
NBDClient *client = opaque;
|
|
|
|
if (client->recv_coroutine) {
|
|
qemu_coroutine_enter(client->recv_coroutine);
|
|
} else {
|
|
qemu_coroutine_enter(qemu_coroutine_create(nbd_trip, client));
|
|
}
|
|
}
|
|
|
|
static void nbd_restart_write(void *opaque)
|
|
{
|
|
NBDClient *client = opaque;
|
|
|
|
qemu_coroutine_enter(client->send_coroutine);
|
|
}
|
|
|
|
static void nbd_set_handlers(NBDClient *client)
|
|
{
|
|
if (client->exp && client->exp->ctx) {
|
|
aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
|
|
true,
|
|
client->can_read ? nbd_read : NULL,
|
|
client->send_coroutine ? nbd_restart_write : NULL,
|
|
client);
|
|
}
|
|
}
|
|
|
|
static void nbd_unset_handlers(NBDClient *client)
|
|
{
|
|
if (client->exp && client->exp->ctx) {
|
|
aio_set_fd_handler(client->exp->ctx, client->sioc->fd,
|
|
true, NULL, NULL, NULL);
|
|
}
|
|
}
|
|
|
|
static void nbd_update_can_read(NBDClient *client)
|
|
{
|
|
bool can_read = client->recv_coroutine ||
|
|
client->nb_requests < MAX_NBD_REQUESTS;
|
|
|
|
if (can_read != client->can_read) {
|
|
client->can_read = can_read;
|
|
nbd_set_handlers(client);
|
|
|
|
/* There is no need to invoke aio_notify(), since aio_set_fd_handler()
|
|
* in nbd_set_handlers() will have taken care of that */
|
|
}
|
|
}
|
|
|
|
static coroutine_fn void nbd_co_client_start(void *opaque)
|
|
{
|
|
NBDClientNewData *data = opaque;
|
|
NBDClient *client = data->client;
|
|
NBDExport *exp = client->exp;
|
|
|
|
if (exp) {
|
|
nbd_export_get(exp);
|
|
}
|
|
if (nbd_negotiate(data)) {
|
|
client_close(client);
|
|
goto out;
|
|
}
|
|
qemu_co_mutex_init(&client->send_lock);
|
|
nbd_set_handlers(client);
|
|
|
|
if (exp) {
|
|
QTAILQ_INSERT_TAIL(&exp->clients, client, next);
|
|
}
|
|
out:
|
|
g_free(data);
|
|
}
|
|
|
|
void nbd_client_new(NBDExport *exp,
|
|
QIOChannelSocket *sioc,
|
|
QCryptoTLSCreds *tlscreds,
|
|
const char *tlsaclname,
|
|
void (*close_fn)(NBDClient *))
|
|
{
|
|
NBDClient *client;
|
|
NBDClientNewData *data = g_new(NBDClientNewData, 1);
|
|
|
|
client = g_malloc0(sizeof(NBDClient));
|
|
client->refcount = 1;
|
|
client->exp = exp;
|
|
client->tlscreds = tlscreds;
|
|
if (tlscreds) {
|
|
object_ref(OBJECT(client->tlscreds));
|
|
}
|
|
client->tlsaclname = g_strdup(tlsaclname);
|
|
client->sioc = sioc;
|
|
object_ref(OBJECT(client->sioc));
|
|
client->ioc = QIO_CHANNEL(sioc);
|
|
object_ref(OBJECT(client->ioc));
|
|
client->can_read = true;
|
|
client->close = close_fn;
|
|
|
|
data->client = client;
|
|
data->co = qemu_coroutine_create(nbd_co_client_start, data);
|
|
qemu_coroutine_enter(data->co);
|
|
}
|