[qemu.git] / nbd / client.c

/*
 *  Copyright (C) 2005  Anthony Liguori <[email protected]>
 *
 *  Network Block Device Client Side
 *
 *  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 <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"
#include "nbd-internal.h"

static int nbd_errno_to_system_errno(int err)
{
    switch (err) {
    case NBD_SUCCESS:
        return 0;
    case NBD_EPERM:
        return EPERM;
    case NBD_EIO:
        return EIO;
    case NBD_ENOMEM:
        return ENOMEM;
    case NBD_ENOSPC:
        return ENOSPC;
    case NBD_EINVAL:
    default:
        return EINVAL;
    }
}

/* Definitions for opaque data types */

static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);

/* That's all folks */

/* Basic flow for negotiation

   Server         Client
   Negotiate

   or

   Server         Client
   Negotiate #1
                  Option
   Negotiate #2

   ----

   followed by

   Server         Client
                  Request
   Response
                  Request
   Response
                  ...
   ...
                  Request (type == 2)

*/


static int nbd_handle_reply_err(uint32_t opt, uint32_t type, Error **errp)
{
    if (!(type & (1 << 31))) {
        return 0;
    }

    switch (type) {
    case NBD_REP_ERR_UNSUP:
        error_setg(errp, "Unsupported option type %x", opt);
        break;

    case NBD_REP_ERR_POLICY:
        error_setg(errp, "Denied by server for option %x", opt);
        break;

    case NBD_REP_ERR_INVALID:
        error_setg(errp, "Invalid data length for option %x", opt);
        break;

    case NBD_REP_ERR_TLS_REQD:
        error_setg(errp, "TLS negotiation required before option %x", opt);
        break;

    default:
        error_setg(errp, "Unknown error code when asking for option %x", opt);
        break;
    }

    return -1;
}

static int nbd_receive_list(QIOChannel *ioc, char **name, Error **errp)
{
    uint64_t magic;
    uint32_t opt;
    uint32_t type;
    uint32_t len;
    uint32_t namelen;

    *name = NULL;
    if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
        error_setg(errp, "failed to read list option magic");
        return -1;
    }
    magic = be64_to_cpu(magic);
    if (magic != NBD_REP_MAGIC) {
        error_setg(errp, "Unexpected option list magic");
        return -1;
    }
    if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
        error_setg(errp, "failed to read list option");
        return -1;
    }
    opt = be32_to_cpu(opt);
    if (opt != NBD_OPT_LIST) {
        error_setg(errp, "Unexpected option type %x expected %x",
                   opt, NBD_OPT_LIST);
        return -1;
    }

    if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
        error_setg(errp, "failed to read list option type");
        return -1;
    }
    type = be32_to_cpu(type);
    if (type == NBD_REP_ERR_UNSUP) {
        return 0;
    }
    if (nbd_handle_reply_err(opt, type, errp) < 0) {
        return -1;
    }

    if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) {
        error_setg(errp, "failed to read option length");
        return -1;
    }
    len = be32_to_cpu(len);

    if (type == NBD_REP_ACK) {
        if (len != 0) {
            error_setg(errp, "length too long for option end");
            return -1;
        }
    } else if (type == NBD_REP_SERVER) {
        if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
            error_setg(errp, "failed to read option name length");
            return -1;
        }
        namelen = be32_to_cpu(namelen);
        if (len != (namelen + sizeof(namelen))) {
            error_setg(errp, "incorrect option mame length");
            return -1;
        }
        if (namelen > 255) {
            error_setg(errp, "export name length too long %d", namelen);
            return -1;
        }

        *name = g_new0(char, namelen + 1);
        if (read_sync(ioc, *name, namelen) != namelen) {
            error_setg(errp, "failed to read export name");
            g_free(*name);
            *name = NULL;
            return -1;
        }
        (*name)[namelen] = '\0';
    } else {
        error_setg(errp, "Unexpected reply type %x expected %x",
                   type, NBD_REP_SERVER);
        return -1;
    }
    return 1;
}


static int nbd_receive_query_exports(QIOChannel *ioc,
                                     const char *wantname,
                                     Error **errp)
{
    uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
    uint32_t opt = cpu_to_be32(NBD_OPT_LIST);
    uint32_t length = 0;
    bool foundExport = false;

    TRACE("Querying export list");
    if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
        error_setg(errp, "Failed to send list option magic");
        return -1;
    }

    if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
        error_setg(errp, "Failed to send list option number");
        return -1;
    }

    if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
        error_setg(errp, "Failed to send list option length");
        return -1;
    }

    TRACE("Reading available export names");
    while (1) {
        char *name = NULL;
        int ret = nbd_receive_list(ioc, &name, errp);

        if (ret < 0) {
            g_free(name);
            name = NULL;
            return -1;
        }
        if (ret == 0) {
            /* Server doesn't support export listing, so
             * we will just assume an export with our
             * wanted name exists */
            foundExport = true;
            break;
        }
        if (name == NULL) {
            TRACE("End of export name list");
            break;
        }
        if (g_str_equal(name, wantname)) {
            foundExport = true;
            TRACE("Found desired export name '%s'", name);
        } else {
            TRACE("Ignored export name '%s'", name);
        }
        g_free(name);
    }

    if (!foundExport) {
        error_setg(errp, "No export with name '%s' available", wantname);
        return -1;
    }

    return 0;
}

static QIOChannel *nbd_receive_starttls(QIOChannel *ioc,
                                        QCryptoTLSCreds *tlscreds,
                                        const char *hostname, Error **errp)
{
    uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
    uint32_t opt = cpu_to_be32(NBD_OPT_STARTTLS);
    uint32_t length = 0;
    uint32_t type;
    QIOChannelTLS *tioc;
    struct NBDTLSHandshakeData data = { 0 };

    TRACE("Requesting TLS from server");
    if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
        error_setg(errp, "Failed to send option magic");
        return NULL;
    }

    if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
        error_setg(errp, "Failed to send option number");
        return NULL;
    }

    if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
        error_setg(errp, "Failed to send option length");
        return NULL;
    }

    TRACE("Getting TLS reply from server1");
    if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
        error_setg(errp, "failed to read option magic");
        return NULL;
    }
    magic = be64_to_cpu(magic);
    if (magic != NBD_REP_MAGIC) {
        error_setg(errp, "Unexpected option magic");
        return NULL;
    }
    TRACE("Getting TLS reply from server2");
    if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
        error_setg(errp, "failed to read option");
        return NULL;
    }
    opt = be32_to_cpu(opt);
    if (opt != NBD_OPT_STARTTLS) {
        error_setg(errp, "Unexpected option type %x expected %x",
                   opt, NBD_OPT_STARTTLS);
        return NULL;
    }

    TRACE("Getting TLS reply from server");
    if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
        error_setg(errp, "failed to read option type");
        return NULL;
    }
    type = be32_to_cpu(type);
    if (type != NBD_REP_ACK) {
        error_setg(errp, "Server rejected request to start TLS %x",
                   type);
        return NULL;
    }

    TRACE("Getting TLS reply from server");
    if (read_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
        error_setg(errp, "failed to read option length");
        return NULL;
    }
    length = be32_to_cpu(length);
    if (length != 0) {
        error_setg(errp, "Start TLS reponse was not zero %x",
                   length);
        return NULL;
    }

    TRACE("TLS request approved, setting up TLS");
    tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
    if (!tioc) {
        return NULL;
    }
    data.loop = g_main_loop_new(g_main_context_default(), FALSE);
    TRACE("Starting TLS hanshake");
    qio_channel_tls_handshake(tioc,
                              nbd_tls_handshake,
                              &data,
                              NULL);

    if (!data.complete) {
        g_main_loop_run(data.loop);
    }
    g_main_loop_unref(data.loop);
    if (data.error) {
        error_propagate(errp, data.error);
        object_unref(OBJECT(tioc));
        return NULL;
    }

    return QIO_CHANNEL(tioc);
}


int nbd_receive_negotiate(QIOChannel *ioc, const char *name, uint32_t *flags,
                          QCryptoTLSCreds *tlscreds, const char *hostname,
                          QIOChannel **outioc,
                          off_t *size, Error **errp)
{
    char buf[256];
    uint64_t magic, s;
    int rc;

    TRACE("Receiving negotiation tlscreds=%p hostname=%s.",
          tlscreds, hostname ? hostname : "<null>");

    rc = -EINVAL;

    if (outioc) {
        *outioc = NULL;
    }
    if (tlscreds && !outioc) {
        error_setg(errp, "Output I/O channel required for TLS");
        goto fail;
    }

    if (read_sync(ioc, buf, 8) != 8) {
        error_setg(errp, "Failed to read data");
        goto fail;
    }

    buf[8] = '\0';
    if (strlen(buf) == 0) {
        error_setg(errp, "Server connection closed unexpectedly");
        goto fail;
    }

    TRACE("Magic is %c%c%c%c%c%c%c%c",
          qemu_isprint(buf[0]) ? buf[0] : '.',
          qemu_isprint(buf[1]) ? buf[1] : '.',
          qemu_isprint(buf[2]) ? buf[2] : '.',
          qemu_isprint(buf[3]) ? buf[3] : '.',
          qemu_isprint(buf[4]) ? buf[4] : '.',
          qemu_isprint(buf[5]) ? buf[5] : '.',
          qemu_isprint(buf[6]) ? buf[6] : '.',
          qemu_isprint(buf[7]) ? buf[7] : '.');

    if (memcmp(buf, "NBDMAGIC", 8) != 0) {
        error_setg(errp, "Invalid magic received");
        goto fail;
    }

    if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
        error_setg(errp, "Failed to read magic");
        goto fail;
    }
    magic = be64_to_cpu(magic);
    TRACE("Magic is 0x%" PRIx64, magic);

    if (magic == NBD_OPTS_MAGIC) {
        uint32_t clientflags = 0;
        uint32_t opt;
        uint32_t namesize;
        uint16_t globalflags;
        uint16_t exportflags;
        bool fixedNewStyle = false;

        if (read_sync(ioc, &globalflags, sizeof(globalflags)) !=
            sizeof(globalflags)) {
            error_setg(errp, "Failed to read server flags");
            goto fail;
        }
        globalflags = be16_to_cpu(globalflags);
        *flags = globalflags << 16;
        TRACE("Global flags are %x", globalflags);
        if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
            fixedNewStyle = true;
            TRACE("Server supports fixed new style");
            clientflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
        }
        /* client requested flags */
        clientflags = cpu_to_be32(clientflags);
        if (write_sync(ioc, &clientflags, sizeof(clientflags)) !=
            sizeof(clientflags)) {
            error_setg(errp, "Failed to send clientflags field");
            goto fail;
        }
        if (tlscreds) {
            if (fixedNewStyle) {
                *outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
                if (!*outioc) {
                    goto fail;
                }
                ioc = *outioc;
            } else {
                error_setg(errp, "Server does not support STARTTLS");
                goto fail;
            }
        }
        if (!name) {
            TRACE("Using default NBD export name \"\"");
            name = "";
        }
        if (fixedNewStyle) {
            /* Check our desired export is present in the
             * server export list. Since NBD_OPT_EXPORT_NAME
             * cannot return an error message, running this
             * query gives us good error reporting if the
             * server required TLS
             */
            if (nbd_receive_query_exports(ioc, name, errp) < 0) {
                goto fail;
            }
        }
        /* write the export name */
        magic = cpu_to_be64(magic);
        if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
            error_setg(errp, "Failed to send export name magic");
            goto fail;
        }
        opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
        if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
            error_setg(errp, "Failed to send export name option number");
            goto fail;
        }
        namesize = cpu_to_be32(strlen(name));
        if (write_sync(ioc, &namesize, sizeof(namesize)) !=
            sizeof(namesize)) {
            error_setg(errp, "Failed to send export name length");
            goto fail;
        }
        if (write_sync(ioc, (char *)name, strlen(name)) != strlen(name)) {
            error_setg(errp, "Failed to send export name");
            goto fail;
        }

        if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
            error_setg(errp, "Failed to read export length");
            goto fail;
        }
        *size = be64_to_cpu(s);
        TRACE("Size is %" PRIu64, *size);

        if (read_sync(ioc, &exportflags, sizeof(exportflags)) !=
            sizeof(exportflags)) {
            error_setg(errp, "Failed to read export flags");
            goto fail;
        }
        exportflags = be16_to_cpu(exportflags);
        *flags |= exportflags;
        TRACE("Export flags are %x", exportflags);
    } else if (magic == NBD_CLIENT_MAGIC) {
        if (name) {
            error_setg(errp, "Server does not support export names");
            goto fail;
        }
        if (tlscreds) {
            error_setg(errp, "Server does not support STARTTLS");
            goto fail;
        }

        if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
            error_setg(errp, "Failed to read export length");
            goto fail;
        }
        *size = be64_to_cpu(s);
        TRACE("Size is %" PRIu64, *size);

        if (read_sync(ioc, flags, sizeof(*flags)) != sizeof(*flags)) {
            error_setg(errp, "Failed to read export flags");
            goto fail;
        }
        *flags = be32_to_cpup(flags);
    } else {
        error_setg(errp, "Bad magic received");
        goto fail;
    }

    if (read_sync(ioc, &buf, 124) != 124) {
        error_setg(errp, "Failed to read reserved block");
        goto fail;
    }
    rc = 0;

fail:
    return rc;
}

#ifdef __linux__
int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size)
{
    TRACE("Setting NBD socket");

    if (ioctl(fd, NBD_SET_SOCK, sioc->fd) < 0) {
        int serrno = errno;
        LOG("Failed to set NBD socket");
        return -serrno;
    }

    TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);

    if (ioctl(fd, NBD_SET_BLKSIZE, (size_t)BDRV_SECTOR_SIZE) < 0) {
        int serrno = errno;
        LOG("Failed setting NBD block size");
        return -serrno;
    }

    TRACE("Setting size to %zd block(s)", (size_t)(size / BDRV_SECTOR_SIZE));

    if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0) {
        int serrno = errno;
        LOG("Failed setting size (in blocks)");
        return -serrno;
    }

    if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
        if (errno == ENOTTY) {
            int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
            TRACE("Setting readonly attribute");

            if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
                int serrno = errno;
                LOG("Failed setting read-only attribute");
                return -serrno;
            }
        } else {
            int serrno = errno;
            LOG("Failed setting flags");
            return -serrno;
        }
    }

    TRACE("Negotiation ended");

    return 0;
}

int nbd_client(int fd)
{
    int ret;
    int serrno;

    TRACE("Doing NBD loop");

    ret = ioctl(fd, NBD_DO_IT);
    if (ret < 0 && errno == EPIPE) {
        /* NBD_DO_IT normally returns EPIPE when someone has disconnected
         * the socket via NBD_DISCONNECT.  We do not want to return 1 in
         * that case.
         */
        ret = 0;
    }
    serrno = errno;

    TRACE("NBD loop returned %d: %s", ret, strerror(serrno));

    TRACE("Clearing NBD queue");
    ioctl(fd, NBD_CLEAR_QUE);

    TRACE("Clearing NBD socket");
    ioctl(fd, NBD_CLEAR_SOCK);

    errno = serrno;
    return ret;
}
#else
int nbd_init(int fd, QIOChannelSocket *ioc, uint32_t flags, off_t size)
{
    return -ENOTSUP;
}

int nbd_client(int fd)
{
    return -ENOTSUP;
}
#endif

ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request)
{
    uint8_t buf[NBD_REQUEST_SIZE];
    ssize_t ret;

    cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
    cpu_to_be32w((uint32_t*)(buf + 4), request->type);
    cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
    cpu_to_be64w((uint64_t*)(buf + 16), request->from);
    cpu_to_be32w((uint32_t*)(buf + 24), request->len);

    TRACE("Sending request to client: "
          "{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
          request->from, request->len, request->handle, request->type);

    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;
}

ssize_t nbd_receive_reply(QIOChannel *ioc, struct nbd_reply *reply)
{
    uint8_t buf[NBD_REPLY_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;
    }

    /* Reply
       [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
       [ 4 ..  7]    error   (0 == no error)
       [ 7 .. 15]    handle
     */

    magic = be32_to_cpup((uint32_t*)buf);
    reply->error  = be32_to_cpup((uint32_t*)(buf + 4));
    reply->handle = be64_to_cpup((uint64_t*)(buf + 8));

    reply->error = nbd_errno_to_system_errno(reply->error);

    TRACE("Got reply: "
          "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
          magic, reply->error, reply->handle);

    if (magic != NBD_REPLY_MAGIC) {
        LOG("invalid magic (got 0x%x)", magic);
        return -EINVAL;
    }
    return 0;
}
Commit	Line	Data
798bfe00 FZ	1	/*
	2	* Copyright (C) 2005 Anthony Liguori <[email protected]>
	3	*
	4	* Network Block Device Client Side
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; under version 2 of the License.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	17	*/
	18
d38ea87a	19	#include "qemu/osdep.h"
798bfe00 FZ	20	#include "nbd-internal.h"
	21
	22	static int nbd_errno_to_system_errno(int err)
	23	{
	24	switch (err) {
	25	case NBD_SUCCESS:
	26	return 0;
	27	case NBD_EPERM:
	28	return EPERM;
	29	case NBD_EIO:
	30	return EIO;
	31	case NBD_ENOMEM:
	32	return ENOMEM;
	33	case NBD_ENOSPC:
	34	return ENOSPC;
	35	case NBD_EINVAL:
	36	default:
	37	return EINVAL;
	38	}
	39	}
	40
	41	/* Definitions for opaque data types */
	42
	43	static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
	44
	45	/* That's all folks */
	46
	47	/* Basic flow for negotiation
	48
	49	Server Client
	50	Negotiate
	51
	52	or
	53
	54	Server Client
	55	Negotiate #1
	56	Option
	57	Negotiate #2
	58
	59	----
	60
	61	followed by
	62
	63	Server Client
	64	Request
	65	Response
	66	Request
	67	Response
	68	...
	69	...
	70	Request (type == 2)
	71
	72	*/
	73
9344e5f5 DB	74
	75	static int nbd_handle_reply_err(uint32_t opt, uint32_t type, Error **errp)
	76	{
	77	if (!(type & (1 << 31))) {
	78	return 0;
	79	}
	80
	81	switch (type) {
	82	case NBD_REP_ERR_UNSUP:
	83	error_setg(errp, "Unsupported option type %x", opt);
	84	break;
	85
f95910fe DB	86	case NBD_REP_ERR_POLICY:
	87	error_setg(errp, "Denied by server for option %x", opt);
	88	break;
	89
9344e5f5 DB	90	case NBD_REP_ERR_INVALID:
	91	error_setg(errp, "Invalid data length for option %x", opt);
	92	break;
	93
f95910fe DB	94	case NBD_REP_ERR_TLS_REQD:
	95	error_setg(errp, "TLS negotiation required before option %x", opt);
	96	break;
	97
9344e5f5 DB	98	default:
	99	error_setg(errp, "Unknown error code when asking for option %x", opt);
	100	break;
	101	}
	102
	103	return -1;
	104	}
	105
	106	static int nbd_receive_list(QIOChannel ioc, char name, Error *errp)
	107	{
	108	uint64_t magic;
	109	uint32_t opt;
	110	uint32_t type;
	111	uint32_t len;
	112	uint32_t namelen;
	113
	114	*name = NULL;
	115	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	116	error_setg(errp, "failed to read list option magic");
	117	return -1;
	118	}
	119	magic = be64_to_cpu(magic);
	120	if (magic != NBD_REP_MAGIC) {
	121	error_setg(errp, "Unexpected option list magic");
	122	return -1;
	123	}
	124	if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	125	error_setg(errp, "failed to read list option");
	126	return -1;
	127	}
	128	opt = be32_to_cpu(opt);
	129	if (opt != NBD_OPT_LIST) {
	130	error_setg(errp, "Unexpected option type %x expected %x",
	131	opt, NBD_OPT_LIST);
	132	return -1;
	133	}
	134
	135	if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
	136	error_setg(errp, "failed to read list option type");
	137	return -1;
	138	}
	139	type = be32_to_cpu(type);
	140	if (type == NBD_REP_ERR_UNSUP) {
	141	return 0;
	142	}
	143	if (nbd_handle_reply_err(opt, type, errp) < 0) {
	144	return -1;
	145	}
	146
	147	if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) {
	148	error_setg(errp, "failed to read option length");
	149	return -1;
	150	}
	151	len = be32_to_cpu(len);
	152
	153	if (type == NBD_REP_ACK) {
	154	if (len != 0) {
	155	error_setg(errp, "length too long for option end");
	156	return -1;
	157	}
	158	} else if (type == NBD_REP_SERVER) {
	159	if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
	160	error_setg(errp, "failed to read option name length");
	161	return -1;
162	}
163	namelen = be32_to_cpu(namelen);
164	if (len != (namelen + sizeof(namelen))) {
165	error_setg(errp, "incorrect option mame length");
166	return -1;
167	}
168	if (namelen > 255) {
169	error_setg(errp, "export name length too long %d", namelen);
170	return -1;
171	}
172
173	*name = g_new0(char, namelen + 1);
174	if (read_sync(ioc, *name, namelen) != namelen) {
175	error_setg(errp, "failed to read export name");
176	g_free(*name);
177	*name = NULL;
178	return -1;
179	}
180	(*name)[namelen] = '\0';
181	} else {
182	error_setg(errp, "Unexpected reply type %x expected %x",
183	type, NBD_REP_SERVER);
184	return -1;
185	}
186	return 1;
187	}
188
189
190	static int nbd_receive_query_exports(QIOChannel *ioc,
191	const char *wantname,
192	Error **errp)
193	{
194	uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
195	uint32_t opt = cpu_to_be32(NBD_OPT_LIST);
196	uint32_t length = 0;
197	bool foundExport = false;
198
199	TRACE("Querying export list");
200	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
201	error_setg(errp, "Failed to send list option magic");
202	return -1;
203	}
204
205	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
206	error_setg(errp, "Failed to send list option number");
207	return -1;
208	}
209
210	if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
211	error_setg(errp, "Failed to send list option length");
212	return -1;
213	}
214
215	TRACE("Reading available export names");
216	while (1) {
217	char *name = NULL;
218	int ret = nbd_receive_list(ioc, &name, errp);
219
220	if (ret < 0) {
221	g_free(name);
222	name = NULL;
223	return -1;
224	}
225	if (ret == 0) {
226	/* Server doesn't support export listing, so
227	* we will just assume an export with our
228	* wanted name exists */
229	foundExport = true;
230	break;
231	}
232	if (name == NULL) {
233	TRACE("End of export name list");
234	break;
235	}
236	if (g_str_equal(name, wantname)) {
237	foundExport = true;
238	TRACE("Found desired export name '%s'", name);
239	} else {
240	TRACE("Ignored export name '%s'", name);
241	}
242	g_free(name);
243	}
244
245	if (!foundExport) {
246	error_setg(errp, "No export with name '%s' available", wantname);
247	return -1;
248	}
249
250	return 0;
251	}
252
f95910fe DB	253	static QIOChannel nbd_receive_starttls(QIOChannel ioc,
	254	QCryptoTLSCreds *tlscreds,
	255	const char hostname, Error *errp)
	256	{
	257	uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
	258	uint32_t opt = cpu_to_be32(NBD_OPT_STARTTLS);
	259	uint32_t length = 0;
	260	uint32_t type;
	261	QIOChannelTLS *tioc;
	262	struct NBDTLSHandshakeData data = { 0 };
	263
	264	TRACE("Requesting TLS from server");
	265	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	266	error_setg(errp, "Failed to send option magic");
	267	return NULL;
	268	}
	269
	270	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	271	error_setg(errp, "Failed to send option number");
	272	return NULL;
	273	}
	274
	275	if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
	276	error_setg(errp, "Failed to send option length");
	277	return NULL;
	278	}
	279
	280	TRACE("Getting TLS reply from server1");
	281	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	282	error_setg(errp, "failed to read option magic");
	283	return NULL;
	284	}
	285	magic = be64_to_cpu(magic);
	286	if (magic != NBD_REP_MAGIC) {
	287	error_setg(errp, "Unexpected option magic");
	288	return NULL;
	289	}
	290	TRACE("Getting TLS reply from server2");
	291	if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	292	error_setg(errp, "failed to read option");
	293	return NULL;
	294	}
	295	opt = be32_to_cpu(opt);
	296	if (opt != NBD_OPT_STARTTLS) {
	297	error_setg(errp, "Unexpected option type %x expected %x",
	298	opt, NBD_OPT_STARTTLS);
	299	return NULL;
	300	}
	301
	302	TRACE("Getting TLS reply from server");
	303	if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
	304	error_setg(errp, "failed to read option type");
	305	return NULL;
	306	}
	307	type = be32_to_cpu(type);
	308	if (type != NBD_REP_ACK) {
	309	error_setg(errp, "Server rejected request to start TLS %x",
	310	type);
	311	return NULL;
	312	}
	313
	314	TRACE("Getting TLS reply from server");
	315	if (read_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
	316	error_setg(errp, "failed to read option length");
317	return NULL;
318	}
319	length = be32_to_cpu(length);
320	if (length != 0) {
321	error_setg(errp, "Start TLS reponse was not zero %x",
322	length);
323	return NULL;
324	}
325
326	TRACE("TLS request approved, setting up TLS");
327	tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
328	if (!tioc) {
329	return NULL;
330	}
331	data.loop = g_main_loop_new(g_main_context_default(), FALSE);
332	TRACE("Starting TLS hanshake");
333	qio_channel_tls_handshake(tioc,
334	nbd_tls_handshake,
335	&data,
336	NULL);
337
338	if (!data.complete) {
339	g_main_loop_run(data.loop);
340	}
341	g_main_loop_unref(data.loop);
342	if (data.error) {
343	error_propagate(errp, data.error);
344	object_unref(OBJECT(tioc));
345	return NULL;
346	}
347
348	return QIO_CHANNEL(tioc);
349	}
350
351
1c778ef7	352	int nbd_receive_negotiate(QIOChannel ioc, const char name, uint32_t *flags,
f95910fe DB	353	QCryptoTLSCreds tlscreds, const char hostname,
f95910fe DB	354	QIOChannel **outioc,
798bfe00 FZ	355	off_t size, Error *errp)
	356	{
	357	char buf[256];
	358	uint64_t magic, s;
798bfe00 FZ	359	int rc;
798bfe00 FZ	360
f95910fe DB	361	TRACE("Receiving negotiation tlscreds=%p hostname=%s.",
f95910fe DB	362	tlscreds, hostname ? hostname : "<null>");
798bfe00 FZ	363
	364	rc = -EINVAL;
	365
f95910fe DB	366	if (outioc) {
	367	*outioc = NULL;
	368	}
	369	if (tlscreds && !outioc) {
	370	error_setg(errp, "Output I/O channel required for TLS");
	371	goto fail;
	372	}
	373
1c778ef7	374	if (read_sync(ioc, buf, 8) != 8) {
798bfe00 FZ	375	error_setg(errp, "Failed to read data");
	376	goto fail;
	377	}
	378
	379	buf[8] = '\0';
	380	if (strlen(buf) == 0) {
	381	error_setg(errp, "Server connection closed unexpectedly");
	382	goto fail;
	383	}
	384
	385	TRACE("Magic is %c%c%c%c%c%c%c%c",
	386	qemu_isprint(buf[0]) ? buf[0] : '.',
	387	qemu_isprint(buf[1]) ? buf[1] : '.',
	388	qemu_isprint(buf[2]) ? buf[2] : '.',
	389	qemu_isprint(buf[3]) ? buf[3] : '.',
	390	qemu_isprint(buf[4]) ? buf[4] : '.',
	391	qemu_isprint(buf[5]) ? buf[5] : '.',
	392	qemu_isprint(buf[6]) ? buf[6] : '.',
	393	qemu_isprint(buf[7]) ? buf[7] : '.');
	394
	395	if (memcmp(buf, "NBDMAGIC", 8) != 0) {
	396	error_setg(errp, "Invalid magic received");
	397	goto fail;
	398	}
	399
1c778ef7	400	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
798bfe00 FZ	401	error_setg(errp, "Failed to read magic");
	402	goto fail;
	403	}
	404	magic = be64_to_cpu(magic);
	405	TRACE("Magic is 0x%" PRIx64, magic);
	406
f72d705f	407	if (magic == NBD_OPTS_MAGIC) {
e2a9d9a3	408	uint32_t clientflags = 0;
798bfe00 FZ	409	uint32_t opt;
798bfe00 FZ	410	uint32_t namesize;
e2a9d9a3 DB	411	uint16_t globalflags;
e2a9d9a3 DB	412	uint16_t exportflags;
9344e5f5	413	bool fixedNewStyle = false;
798bfe00	414
e2a9d9a3 DB	415	if (read_sync(ioc, &globalflags, sizeof(globalflags)) !=
e2a9d9a3 DB	416	sizeof(globalflags)) {
798bfe00 FZ	417	error_setg(errp, "Failed to read server flags");
	418	goto fail;
	419	}
9344e5f5 DB	420	globalflags = be16_to_cpu(globalflags);
	421	*flags = globalflags << 16;
	422	TRACE("Global flags are %x", globalflags);
e2a9d9a3	423	if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
9344e5f5	424	fixedNewStyle = true;
e2a9d9a3 DB	425	TRACE("Server supports fixed new style");
	426	clientflags \|= NBD_FLAG_C_FIXED_NEWSTYLE;
	427	}
	428	/* client requested flags */
9344e5f5	429	clientflags = cpu_to_be32(clientflags);
e2a9d9a3 DB	430	if (write_sync(ioc, &clientflags, sizeof(clientflags)) !=
	431	sizeof(clientflags)) {
	432	error_setg(errp, "Failed to send clientflags field");
798bfe00 FZ	433	goto fail;
798bfe00 FZ	434	}
f95910fe DB	435	if (tlscreds) {
	436	if (fixedNewStyle) {
	437	*outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
	438	if (!*outioc) {
	439	goto fail;
	440	}
	441	ioc = *outioc;
	442	} else {
	443	error_setg(errp, "Server does not support STARTTLS");
	444	goto fail;
	445	}
	446	}
f72d705f	447	if (!name) {
69b49502 DB	448	TRACE("Using default NBD export name \"\"");
69b49502 DB	449	name = "";
f72d705f	450	}
9344e5f5 DB	451	if (fixedNewStyle) {
	452	/* Check our desired export is present in the
	453	* server export list. Since NBD_OPT_EXPORT_NAME
	454	* cannot return an error message, running this
	455	* query gives us good error reporting if the
	456	* server required TLS
	457	*/
	458	if (nbd_receive_query_exports(ioc, name, errp) < 0) {
	459	goto fail;
	460	}
	461	}
	462	/* write the export name */
798bfe00	463	magic = cpu_to_be64(magic);
1c778ef7	464	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
798bfe00 FZ	465	error_setg(errp, "Failed to send export name magic");
	466	goto fail;
	467	}
	468	opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
1c778ef7	469	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
798bfe00 FZ	470	error_setg(errp, "Failed to send export name option number");
	471	goto fail;
	472	}
	473	namesize = cpu_to_be32(strlen(name));
1c778ef7	474	if (write_sync(ioc, &namesize, sizeof(namesize)) !=
798bfe00 FZ	475	sizeof(namesize)) {
	476	error_setg(errp, "Failed to send export name length");
	477	goto fail;
	478	}
1c778ef7	479	if (write_sync(ioc, (char *)name, strlen(name)) != strlen(name)) {
798bfe00 FZ	480	error_setg(errp, "Failed to send export name");
	481	goto fail;
	482	}
f72d705f DB	483
	484	if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
	485	error_setg(errp, "Failed to read export length");
798bfe00 FZ	486	goto fail;
798bfe00 FZ	487	}
f72d705f DB	488	*size = be64_to_cpu(s);
f72d705f DB	489	TRACE("Size is %" PRIu64, *size);
798bfe00	490
e2a9d9a3 DB	491	if (read_sync(ioc, &exportflags, sizeof(exportflags)) !=
e2a9d9a3 DB	492	sizeof(exportflags)) {
f72d705f DB	493	error_setg(errp, "Failed to read export flags");
	494	goto fail;
	495	}
9344e5f5 DB	496	exportflags = be16_to_cpu(exportflags);
	497	*flags \|= exportflags;
	498	TRACE("Export flags are %x", exportflags);
f72d705f DB	499	} else if (magic == NBD_CLIENT_MAGIC) {
	500	if (name) {
	501	error_setg(errp, "Server does not support export names");
	502	goto fail;
	503	}
f95910fe DB	504	if (tlscreds) {
	505	error_setg(errp, "Server does not support STARTTLS");
	506	goto fail;
	507	}
f72d705f DB	508
	509	if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
	510	error_setg(errp, "Failed to read export length");
	511	goto fail;
	512	}
	513	*size = be64_to_cpu(s);
	514	TRACE("Size is %" PRIu64, *size);
798bfe00	515
1c778ef7	516	if (read_sync(ioc, flags, sizeof(flags)) != sizeof(flags)) {
798bfe00 FZ	517	error_setg(errp, "Failed to read export flags");
	518	goto fail;
	519	}
	520	*flags = be32_to_cpup(flags);
	521	} else {
f72d705f DB	522	error_setg(errp, "Bad magic received");
f72d705f DB	523	goto fail;
798bfe00	524	}
f72d705f	525
1c778ef7	526	if (read_sync(ioc, &buf, 124) != 124) {
798bfe00 FZ	527	error_setg(errp, "Failed to read reserved block");
	528	goto fail;
	529	}
	530	rc = 0;
	531
	532	fail:
	533	return rc;
	534	}
	535
	536	#ifdef __linux__
1c778ef7	537	int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size)
798bfe00 FZ	538	{
	539	TRACE("Setting NBD socket");
	540
1c778ef7	541	if (ioctl(fd, NBD_SET_SOCK, sioc->fd) < 0) {
798bfe00 FZ	542	int serrno = errno;
	543	LOG("Failed to set NBD socket");
	544	return -serrno;
	545	}
	546
	547	TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);
	548
	549	if (ioctl(fd, NBD_SET_BLKSIZE, (size_t)BDRV_SECTOR_SIZE) < 0) {
	550	int serrno = errno;
	551	LOG("Failed setting NBD block size");
	552	return -serrno;
	553	}
	554
	555	TRACE("Setting size to %zd block(s)", (size_t)(size / BDRV_SECTOR_SIZE));
	556
	557	if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0) {
	558	int serrno = errno;
	559	LOG("Failed setting size (in blocks)");
	560	return -serrno;
	561	}
	562
	563	if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
	564	if (errno == ENOTTY) {
	565	int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
	566	TRACE("Setting readonly attribute");
	567
	568	if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
	569	int serrno = errno;
	570	LOG("Failed setting read-only attribute");
	571	return -serrno;
	572	}
	573	} else {
	574	int serrno = errno;
	575	LOG("Failed setting flags");
	576	return -serrno;
	577	}
	578	}
	579
	580	TRACE("Negotiation ended");
	581
	582	return 0;
	583	}
	584
	585	int nbd_client(int fd)
	586	{
	587	int ret;
	588	int serrno;
	589
	590	TRACE("Doing NBD loop");
	591
	592	ret = ioctl(fd, NBD_DO_IT);
	593	if (ret < 0 && errno == EPIPE) {
	594	/* NBD_DO_IT normally returns EPIPE when someone has disconnected
	595	* the socket via NBD_DISCONNECT. We do not want to return 1 in
	596	* that case.
	597	*/
	598	ret = 0;
	599	}
	600	serrno = errno;
	601
	602	TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
	603
	604	TRACE("Clearing NBD queue");
	605	ioctl(fd, NBD_CLEAR_QUE);
606
607	TRACE("Clearing NBD socket");
608	ioctl(fd, NBD_CLEAR_SOCK);
609
610	errno = serrno;
611	return ret;
612	}
613	#else
1c778ef7	614	int nbd_init(int fd, QIOChannelSocket *ioc, uint32_t flags, off_t size)
798bfe00 FZ	615	{
	616	return -ENOTSUP;
	617	}
	618
	619	int nbd_client(int fd)
	620	{
	621	return -ENOTSUP;
	622	}
	623	#endif
	624
1c778ef7	625	ssize_t nbd_send_request(QIOChannel ioc, struct nbd_request request)
798bfe00 FZ	626	{
	627	uint8_t buf[NBD_REQUEST_SIZE];
	628	ssize_t ret;
	629
	630	cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
	631	cpu_to_be32w((uint32_t*)(buf + 4), request->type);
	632	cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
	633	cpu_to_be64w((uint64_t*)(buf + 16), request->from);
	634	cpu_to_be32w((uint32_t*)(buf + 24), request->len);
	635
	636	TRACE("Sending request to client: "
	637	"{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
	638	request->from, request->len, request->handle, request->type);
	639
1c778ef7	640	ret = write_sync(ioc, buf, sizeof(buf));
798bfe00 FZ	641	if (ret < 0) {
	642	return ret;
	643	}
	644
	645	if (ret != sizeof(buf)) {
	646	LOG("writing to socket failed");
	647	return -EINVAL;
	648	}
	649	return 0;
	650	}
	651
1c778ef7	652	ssize_t nbd_receive_reply(QIOChannel ioc, struct nbd_reply reply)
798bfe00 FZ	653	{
	654	uint8_t buf[NBD_REPLY_SIZE];
	655	uint32_t magic;
	656	ssize_t ret;
	657
1c778ef7	658	ret = read_sync(ioc, buf, sizeof(buf));
798bfe00 FZ	659	if (ret < 0) {
	660	return ret;
	661	}
	662
	663	if (ret != sizeof(buf)) {
	664	LOG("read failed");
	665	return -EINVAL;
	666	}
	667
	668	/* Reply
	669	[ 0 .. 3] magic (NBD_REPLY_MAGIC)
	670	[ 4 .. 7] error (0 == no error)
	671	[ 7 .. 15] handle
	672	*/
	673
	674	magic = be32_to_cpup((uint32_t*)buf);
	675	reply->error = be32_to_cpup((uint32_t*)(buf + 4));
	676	reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
	677
	678	reply->error = nbd_errno_to_system_errno(reply->error);
	679
	680	TRACE("Got reply: "
	681	"{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
	682	magic, reply->error, reply->handle);
	683
	684	if (magic != NBD_REPLY_MAGIC) {
	685	LOG("invalid magic (got 0x%x)", magic);
	686	return -EINVAL;
	687	}
	688	return 0;
	689	}
	690