[mirror_qemu.git] / nbd / client.c

/*
 *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
 *
 *  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 "qapi/error.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)

*/


/* If type represents success, return 1 without further action.
 * If type represents an error reply, consume the rest of the packet on ioc.
 * Then return 0 for unsupported (so the client can fall back to
 * other approaches), or -1 with errp set for other errors.
 */
static int nbd_handle_reply_err(QIOChannel *ioc, uint32_t opt, uint32_t type,
                                Error **errp)
{
    uint32_t len;
    char *msg = NULL;
    int result = -1;

    if (!(type & (1 << 31))) {
        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 (len) {
        if (len > NBD_MAX_BUFFER_SIZE) {
            error_setg(errp, "server's error message is too long");
            goto cleanup;
        }
        msg = g_malloc(len + 1);
        if (read_sync(ioc, msg, len) != len) {
            error_setg(errp, "failed to read option error message");
            goto cleanup;
        }
        msg[len] = '\0';
    }

    switch (type) {
    case NBD_REP_ERR_UNSUP:
        TRACE("server doesn't understand request %" PRIx32
              ", attempting fallback", opt);
        result = 0;
        goto cleanup;

    case NBD_REP_ERR_POLICY:
        error_setg(errp, "Denied by server for option %" PRIx32, opt);
        break;

    case NBD_REP_ERR_INVALID:
        error_setg(errp, "Invalid data length for option %" PRIx32, opt);
        break;

    case NBD_REP_ERR_TLS_REQD:
        error_setg(errp, "TLS negotiation required before option %" PRIx32,
                   opt);
        break;

    default:
        error_setg(errp, "Unknown error code when asking for option %" PRIx32,
                   opt);
        break;
    }

    if (msg) {
        error_append_hint(errp, "%s\n", msg);
    }

 cleanup:
    g_free(msg);
    return result;
}

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;
    int error;

    *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 %" PRIx32 " 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);
    error = nbd_handle_reply_err(ioc, opt, type, errp);
    if (error <= 0) {
        return error;
    }

    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 (len < sizeof(namelen) || len > NBD_MAX_BUFFER_SIZE) {
            error_setg(errp, "incorrect option length");
            return -1;
        }
        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);
        len -= sizeof(namelen);
        if (len < namelen) {
            error_setg(errp, "incorrect option name length");
            return -1;
        }
        if (namelen > 255) {
            error_setg(errp, "export name length too long %" PRIu32, 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';
        len -= namelen;
        if (len) {
            char *buf = g_malloc(len + 1);
            if (read_sync(ioc, buf, len) != len) {
                error_setg(errp, "failed to read export description");
                g_free(*name);
                g_free(buf);
                *name = NULL;
                return -1;
            }
            buf[len] = '\0';
            TRACE("Ignoring export description: %s", buf);
            g_free(buf);
        }
    } else {
        error_setg(errp, "Unexpected reply type %" PRIx32 " 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 %" PRIx32 " 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 %" PRIx32,
                   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 response was not zero %" PRIu32,
                   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 handshake");
    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 %" PRIx32, 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 %" PRIx16, 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_cpu(*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;
}

int nbd_disconnect(int fd)
{
    ioctl(fd, NBD_CLEAR_QUE);
    ioctl(fd, NBD_DISCONNECT);
    ioctl(fd, NBD_CLEAR_SOCK);
    return 0;
}

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

int nbd_client(int fd)
{
    return -ENOTSUP;
}
int nbd_disconnect(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;

    TRACE("Sending request to server: "
          "{ .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64
          ", .type=%" PRIu16 " }",
          request->from, request->len, request->handle, request->type);

    stl_be_p(buf, NBD_REQUEST_MAGIC);
    stl_be_p(buf + 4, request->type);
    stq_be_p(buf + 8, request->handle);
    stq_be_p(buf + 16, request->from);
    stl_be_p(buf + 24, request->len);

    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 = ldl_be_p(buf);
    reply->error  = ldl_be_p(buf + 4);
    reply->handle = ldq_be_p(buf + 8);

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

    TRACE("Got reply: { magic = 0x%" PRIx32 ", .error = % " PRId32
          ", handle = %" PRIu64" }",
          magic, reply->error, reply->handle);

    if (magic != NBD_REPLY_MAGIC) {
        LOG("invalid magic (got 0x%" PRIx32 ")", magic);
        return -EINVAL;
    }
    return 0;
}
Commit	Line	Data
798bfe00 FZ	1	/*
	2	* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
	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"
da34e65c	20	#include "qapi/error.h"
798bfe00 FZ	21	#include "nbd-internal.h"
	22
	23	static int nbd_errno_to_system_errno(int err)
	24	{
	25	switch (err) {
	26	case NBD_SUCCESS:
	27	return 0;
	28	case NBD_EPERM:
	29	return EPERM;
	30	case NBD_EIO:
	31	return EIO;
	32	case NBD_ENOMEM:
	33	return ENOMEM;
	34	case NBD_ENOSPC:
	35	return ENOSPC;
	36	case NBD_EINVAL:
	37	default:
	38	return EINVAL;
	39	}
	40	}
	41
	42	/* Definitions for opaque data types */
	43
	44	static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
	45
	46	/* That's all folks */
	47
	48	/* Basic flow for negotiation
	49
	50	Server Client
	51	Negotiate
	52
	53	or
	54
	55	Server Client
	56	Negotiate #1
	57	Option
	58	Negotiate #2
	59
	60	----
	61
	62	followed by
	63
	64	Server Client
	65	Request
	66	Response
	67	Request
	68	Response
	69	...
	70	...
	71	Request (type == 2)
	72
	73	*/
	74
9344e5f5	75
6ff58164 AB	76	/* If type represents success, return 1 without further action.
	77	* If type represents an error reply, consume the rest of the packet on ioc.
	78	* Then return 0 for unsupported (so the client can fall back to
	79	* other approaches), or -1 with errp set for other errors.
	80	*/
	81	static int nbd_handle_reply_err(QIOChannel *ioc, uint32_t opt, uint32_t type,
	82	Error **errp)
9344e5f5	83	{
6ff58164 AB	84	uint32_t len;
	85	char *msg = NULL;
	86	int result = -1;
	87
9344e5f5	88	if (!(type & (1 << 31))) {
6ff58164 AB	89	return 1;
	90	}
	91
	92	if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) {
	93	error_setg(errp, "failed to read option length");
	94	return -1;
	95	}
	96	len = be32_to_cpu(len);
	97	if (len) {
	98	if (len > NBD_MAX_BUFFER_SIZE) {
	99	error_setg(errp, "server's error message is too long");
	100	goto cleanup;
	101	}
	102	msg = g_malloc(len + 1);
	103	if (read_sync(ioc, msg, len) != len) {
	104	error_setg(errp, "failed to read option error message");
	105	goto cleanup;
	106	}
	107	msg[len] = '\0';
9344e5f5 DB	108	}
	109
	110	switch (type) {
	111	case NBD_REP_ERR_UNSUP:
2cb34749 EB	112	TRACE("server doesn't understand request %" PRIx32
2cb34749 EB	113	", attempting fallback", opt);
6ff58164 AB	114	result = 0;
6ff58164 AB	115	goto cleanup;
9344e5f5	116
f95910fe	117	case NBD_REP_ERR_POLICY:
2cb34749	118	error_setg(errp, "Denied by server for option %" PRIx32, opt);
f95910fe DB	119	break;
f95910fe DB	120
9344e5f5	121	case NBD_REP_ERR_INVALID:
2cb34749	122	error_setg(errp, "Invalid data length for option %" PRIx32, opt);
9344e5f5 DB	123	break;
9344e5f5 DB	124
f95910fe	125	case NBD_REP_ERR_TLS_REQD:
2cb34749 EB	126	error_setg(errp, "TLS negotiation required before option %" PRIx32,
2cb34749 EB	127	opt);
f95910fe DB	128	break;
f95910fe DB	129
9344e5f5	130	default:
2cb34749 EB	131	error_setg(errp, "Unknown error code when asking for option %" PRIx32,
2cb34749 EB	132	opt);
9344e5f5 DB	133	break;
	134	}
	135
6ff58164 AB	136	if (msg) {
	137	error_append_hint(errp, "%s\n", msg);
	138	}
	139
	140	cleanup:
	141	g_free(msg);
	142	return result;
9344e5f5 DB	143	}
	144
	145	static int nbd_receive_list(QIOChannel ioc, char name, Error *errp)
	146	{
	147	uint64_t magic;
	148	uint32_t opt;
	149	uint32_t type;
	150	uint32_t len;
	151	uint32_t namelen;
6ff58164	152	int error;
9344e5f5 DB	153
	154	*name = NULL;
	155	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	156	error_setg(errp, "failed to read list option magic");
	157	return -1;
	158	}
	159	magic = be64_to_cpu(magic);
	160	if (magic != NBD_REP_MAGIC) {
	161	error_setg(errp, "Unexpected option list magic");
	162	return -1;
	163	}
	164	if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	165	error_setg(errp, "failed to read list option");
	166	return -1;
	167	}
	168	opt = be32_to_cpu(opt);
	169	if (opt != NBD_OPT_LIST) {
2cb34749	170	error_setg(errp, "Unexpected option type %" PRIx32 " expected %x",
9344e5f5 DB	171	opt, NBD_OPT_LIST);
	172	return -1;
	173	}
	174
	175	if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
	176	error_setg(errp, "failed to read list option type");
	177	return -1;
	178	}
	179	type = be32_to_cpu(type);
6ff58164 AB	180	error = nbd_handle_reply_err(ioc, opt, type, errp);
	181	if (error <= 0) {
	182	return error;
9344e5f5 DB	183	}
	184
	185	if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) {
	186	error_setg(errp, "failed to read option length");
	187	return -1;
	188	}
	189	len = be32_to_cpu(len);
	190
	191	if (type == NBD_REP_ACK) {
	192	if (len != 0) {
	193	error_setg(errp, "length too long for option end");
	194	return -1;
	195	}
	196	} else if (type == NBD_REP_SERVER) {
200650d4 EB	197	if (len < sizeof(namelen) \|\| len > NBD_MAX_BUFFER_SIZE) {
	198	error_setg(errp, "incorrect option length");
	199	return -1;
	200	}
9344e5f5 DB	201	if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
	202	error_setg(errp, "failed to read option name length");
	203	return -1;
	204	}
	205	namelen = be32_to_cpu(namelen);
200650d4 EB	206	len -= sizeof(namelen);
	207	if (len < namelen) {
	208	error_setg(errp, "incorrect option name length");
9344e5f5 DB	209	return -1;
	210	}
	211	if (namelen > 255) {
2cb34749	212	error_setg(errp, "export name length too long %" PRIu32, namelen);
9344e5f5 DB	213	return -1;
	214	}
	215
	216	*name = g_new0(char, namelen + 1);
	217	if (read_sync(ioc, *name, namelen) != namelen) {
	218	error_setg(errp, "failed to read export name");
	219	g_free(*name);
	220	*name = NULL;
	221	return -1;
	222	}
	223	(*name)[namelen] = '\0';
200650d4 EB	224	len -= namelen;
	225	if (len) {
	226	char *buf = g_malloc(len + 1);
	227	if (read_sync(ioc, buf, len) != len) {
	228	error_setg(errp, "failed to read export description");
	229	g_free(*name);
	230	g_free(buf);
	231	*name = NULL;
	232	return -1;
	233	}
	234	buf[len] = '\0';
	235	TRACE("Ignoring export description: %s", buf);
	236	g_free(buf);
	237	}
9344e5f5	238	} else {
2cb34749	239	error_setg(errp, "Unexpected reply type %" PRIx32 " expected %x",
9344e5f5 DB	240	type, NBD_REP_SERVER);
	241	return -1;
	242	}
	243	return 1;
	244	}
	245
	246
	247	static int nbd_receive_query_exports(QIOChannel *ioc,
	248	const char *wantname,
	249	Error **errp)
	250	{
	251	uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
	252	uint32_t opt = cpu_to_be32(NBD_OPT_LIST);
	253	uint32_t length = 0;
	254	bool foundExport = false;
	255
	256	TRACE("Querying export list");
	257	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	258	error_setg(errp, "Failed to send list option magic");
	259	return -1;
	260	}
	261
	262	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	263	error_setg(errp, "Failed to send list option number");
	264	return -1;
	265	}
	266
	267	if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
	268	error_setg(errp, "Failed to send list option length");
	269	return -1;
	270	}
	271
	272	TRACE("Reading available export names");
	273	while (1) {
	274	char *name = NULL;
	275	int ret = nbd_receive_list(ioc, &name, errp);
	276
	277	if (ret < 0) {
	278	g_free(name);
	279	name = NULL;
	280	return -1;
	281	}
	282	if (ret == 0) {
	283	/* Server doesn't support export listing, so
	284	* we will just assume an export with our
	285	* wanted name exists */
	286	foundExport = true;
	287	break;
	288	}
	289	if (name == NULL) {
	290	TRACE("End of export name list");
	291	break;
	292	}
	293	if (g_str_equal(name, wantname)) {
	294	foundExport = true;
	295	TRACE("Found desired export name '%s'", name);
	296	} else {
	297	TRACE("Ignored export name '%s'", name);
	298	}
	299	g_free(name);
	300	}
	301
	302	if (!foundExport) {
	303	error_setg(errp, "No export with name '%s' available", wantname);
304	return -1;
305	}
306
307	return 0;
308	}
309
f95910fe DB	310	static QIOChannel nbd_receive_starttls(QIOChannel ioc,
	311	QCryptoTLSCreds *tlscreds,
	312	const char hostname, Error *errp)
	313	{
	314	uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
	315	uint32_t opt = cpu_to_be32(NBD_OPT_STARTTLS);
	316	uint32_t length = 0;
	317	uint32_t type;
	318	QIOChannelTLS *tioc;
	319	struct NBDTLSHandshakeData data = { 0 };
	320
	321	TRACE("Requesting TLS from server");
	322	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	323	error_setg(errp, "Failed to send option magic");
	324	return NULL;
	325	}
	326
	327	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	328	error_setg(errp, "Failed to send option number");
	329	return NULL;
	330	}
	331
	332	if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
	333	error_setg(errp, "Failed to send option length");
	334	return NULL;
	335	}
	336
	337	TRACE("Getting TLS reply from server1");
	338	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	339	error_setg(errp, "failed to read option magic");
	340	return NULL;
	341	}
	342	magic = be64_to_cpu(magic);
	343	if (magic != NBD_REP_MAGIC) {
	344	error_setg(errp, "Unexpected option magic");
	345	return NULL;
	346	}
	347	TRACE("Getting TLS reply from server2");
	348	if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	349	error_setg(errp, "failed to read option");
	350	return NULL;
	351	}
	352	opt = be32_to_cpu(opt);
	353	if (opt != NBD_OPT_STARTTLS) {
2cb34749	354	error_setg(errp, "Unexpected option type %" PRIx32 " expected %x",
f95910fe DB	355	opt, NBD_OPT_STARTTLS);
	356	return NULL;
	357	}
	358
	359	TRACE("Getting TLS reply from server");
	360	if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
	361	error_setg(errp, "failed to read option type");
	362	return NULL;
	363	}
	364	type = be32_to_cpu(type);
	365	if (type != NBD_REP_ACK) {
2cb34749	366	error_setg(errp, "Server rejected request to start TLS %" PRIx32,
f95910fe DB	367	type);
	368	return NULL;
	369	}
	370
	371	TRACE("Getting TLS reply from server");
	372	if (read_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
	373	error_setg(errp, "failed to read option length");
	374	return NULL;
	375	}
	376	length = be32_to_cpu(length);
	377	if (length != 0) {
2cb34749	378	error_setg(errp, "Start TLS response was not zero %" PRIu32,
f95910fe DB	379	length);
	380	return NULL;
	381	}
	382
	383	TRACE("TLS request approved, setting up TLS");
	384	tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
	385	if (!tioc) {
	386	return NULL;
	387	}
	388	data.loop = g_main_loop_new(g_main_context_default(), FALSE);
2cb34749	389	TRACE("Starting TLS handshake");
f95910fe DB	390	qio_channel_tls_handshake(tioc,
	391	nbd_tls_handshake,
	392	&data,
	393	NULL);
	394
	395	if (!data.complete) {
	396	g_main_loop_run(data.loop);
	397	}
	398	g_main_loop_unref(data.loop);
	399	if (data.error) {
	400	error_propagate(errp, data.error);
	401	object_unref(OBJECT(tioc));
	402	return NULL;
	403	}
	404
	405	return QIO_CHANNEL(tioc);
	406	}
	407
	408
1c778ef7	409	int nbd_receive_negotiate(QIOChannel ioc, const char name, uint32_t *flags,
f95910fe DB	410	QCryptoTLSCreds tlscreds, const char hostname,
f95910fe DB	411	QIOChannel **outioc,
798bfe00 FZ	412	off_t size, Error *errp)
	413	{
	414	char buf[256];
	415	uint64_t magic, s;
798bfe00 FZ	416	int rc;
798bfe00 FZ	417
f95910fe DB	418	TRACE("Receiving negotiation tlscreds=%p hostname=%s.",
f95910fe DB	419	tlscreds, hostname ? hostname : "<null>");
798bfe00 FZ	420
	421	rc = -EINVAL;
	422
f95910fe DB	423	if (outioc) {
	424	*outioc = NULL;
	425	}
	426	if (tlscreds && !outioc) {
	427	error_setg(errp, "Output I/O channel required for TLS");
	428	goto fail;
	429	}
	430
1c778ef7	431	if (read_sync(ioc, buf, 8) != 8) {
798bfe00 FZ	432	error_setg(errp, "Failed to read data");
	433	goto fail;
	434	}
	435
	436	buf[8] = '\0';
	437	if (strlen(buf) == 0) {
	438	error_setg(errp, "Server connection closed unexpectedly");
	439	goto fail;
	440	}
	441
	442	TRACE("Magic is %c%c%c%c%c%c%c%c",
	443	qemu_isprint(buf[0]) ? buf[0] : '.',
	444	qemu_isprint(buf[1]) ? buf[1] : '.',
	445	qemu_isprint(buf[2]) ? buf[2] : '.',
	446	qemu_isprint(buf[3]) ? buf[3] : '.',
	447	qemu_isprint(buf[4]) ? buf[4] : '.',
	448	qemu_isprint(buf[5]) ? buf[5] : '.',
	449	qemu_isprint(buf[6]) ? buf[6] : '.',
	450	qemu_isprint(buf[7]) ? buf[7] : '.');
	451
	452	if (memcmp(buf, "NBDMAGIC", 8) != 0) {
	453	error_setg(errp, "Invalid magic received");
	454	goto fail;
	455	}
	456
1c778ef7	457	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
798bfe00 FZ	458	error_setg(errp, "Failed to read magic");
	459	goto fail;
	460	}
	461	magic = be64_to_cpu(magic);
	462	TRACE("Magic is 0x%" PRIx64, magic);
	463
f72d705f	464	if (magic == NBD_OPTS_MAGIC) {
e2a9d9a3	465	uint32_t clientflags = 0;
798bfe00 FZ	466	uint32_t opt;
798bfe00 FZ	467	uint32_t namesize;
e2a9d9a3 DB	468	uint16_t globalflags;
e2a9d9a3 DB	469	uint16_t exportflags;
9344e5f5	470	bool fixedNewStyle = false;
798bfe00	471
e2a9d9a3 DB	472	if (read_sync(ioc, &globalflags, sizeof(globalflags)) !=
e2a9d9a3 DB	473	sizeof(globalflags)) {
798bfe00 FZ	474	error_setg(errp, "Failed to read server flags");
	475	goto fail;
	476	}
9344e5f5 DB	477	globalflags = be16_to_cpu(globalflags);
9344e5f5 DB	478	*flags = globalflags << 16;
2cb34749	479	TRACE("Global flags are %" PRIx32, globalflags);
e2a9d9a3	480	if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
9344e5f5	481	fixedNewStyle = true;
e2a9d9a3 DB	482	TRACE("Server supports fixed new style");
	483	clientflags \|= NBD_FLAG_C_FIXED_NEWSTYLE;
	484	}
	485	/* client requested flags */
9344e5f5	486	clientflags = cpu_to_be32(clientflags);
e2a9d9a3 DB	487	if (write_sync(ioc, &clientflags, sizeof(clientflags)) !=
	488	sizeof(clientflags)) {
	489	error_setg(errp, "Failed to send clientflags field");
798bfe00 FZ	490	goto fail;
798bfe00 FZ	491	}
f95910fe DB	492	if (tlscreds) {
	493	if (fixedNewStyle) {
	494	*outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
	495	if (!*outioc) {
	496	goto fail;
	497	}
	498	ioc = *outioc;
	499	} else {
	500	error_setg(errp, "Server does not support STARTTLS");
	501	goto fail;
	502	}
	503	}
f72d705f	504	if (!name) {
69b49502 DB	505	TRACE("Using default NBD export name \"\"");
69b49502 DB	506	name = "";
f72d705f	507	}
9344e5f5 DB	508	if (fixedNewStyle) {
	509	/* Check our desired export is present in the
	510	* server export list. Since NBD_OPT_EXPORT_NAME
	511	* cannot return an error message, running this
	512	* query gives us good error reporting if the
	513	* server required TLS
	514	*/
	515	if (nbd_receive_query_exports(ioc, name, errp) < 0) {
	516	goto fail;
	517	}
	518	}
	519	/* write the export name */
798bfe00	520	magic = cpu_to_be64(magic);
1c778ef7	521	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
798bfe00 FZ	522	error_setg(errp, "Failed to send export name magic");
	523	goto fail;
	524	}
	525	opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
1c778ef7	526	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
798bfe00 FZ	527	error_setg(errp, "Failed to send export name option number");
	528	goto fail;
	529	}
	530	namesize = cpu_to_be32(strlen(name));
1c778ef7	531	if (write_sync(ioc, &namesize, sizeof(namesize)) !=
798bfe00 FZ	532	sizeof(namesize)) {
	533	error_setg(errp, "Failed to send export name length");
	534	goto fail;
	535	}
1c778ef7	536	if (write_sync(ioc, (char *)name, strlen(name)) != strlen(name)) {
798bfe00 FZ	537	error_setg(errp, "Failed to send export name");
	538	goto fail;
	539	}
f72d705f DB	540
	541	if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
	542	error_setg(errp, "Failed to read export length");
798bfe00 FZ	543	goto fail;
798bfe00 FZ	544	}
f72d705f DB	545	*size = be64_to_cpu(s);
f72d705f DB	546	TRACE("Size is %" PRIu64, *size);
798bfe00	547
e2a9d9a3 DB	548	if (read_sync(ioc, &exportflags, sizeof(exportflags)) !=
e2a9d9a3 DB	549	sizeof(exportflags)) {
f72d705f DB	550	error_setg(errp, "Failed to read export flags");
	551	goto fail;
	552	}
9344e5f5 DB	553	exportflags = be16_to_cpu(exportflags);
9344e5f5 DB	554	*flags \|= exportflags;
2cb34749	555	TRACE("Export flags are %" PRIx16, exportflags);
f72d705f DB	556	} else if (magic == NBD_CLIENT_MAGIC) {
	557	if (name) {
	558	error_setg(errp, "Server does not support export names");
	559	goto fail;
	560	}
f95910fe DB	561	if (tlscreds) {
	562	error_setg(errp, "Server does not support STARTTLS");
	563	goto fail;
	564	}
f72d705f DB	565
	566	if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
	567	error_setg(errp, "Failed to read export length");
	568	goto fail;
	569	}
	570	*size = be64_to_cpu(s);
	571	TRACE("Size is %" PRIu64, *size);
798bfe00	572
1c778ef7	573	if (read_sync(ioc, flags, sizeof(flags)) != sizeof(flags)) {
798bfe00 FZ	574	error_setg(errp, "Failed to read export flags");
	575	goto fail;
	576	}
773dce3c	577	flags = be32_to_cpu(flags);
798bfe00	578	} else {
f72d705f DB	579	error_setg(errp, "Bad magic received");
f72d705f DB	580	goto fail;
798bfe00	581	}
f72d705f	582
1c778ef7	583	if (read_sync(ioc, &buf, 124) != 124) {
798bfe00 FZ	584	error_setg(errp, "Failed to read reserved block");
	585	goto fail;
	586	}
	587	rc = 0;
	588
	589	fail:
	590	return rc;
	591	}
	592
	593	#ifdef __linux__
1c778ef7	594	int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size)
798bfe00 FZ	595	{
	596	TRACE("Setting NBD socket");
	597
1c778ef7	598	if (ioctl(fd, NBD_SET_SOCK, sioc->fd) < 0) {
798bfe00 FZ	599	int serrno = errno;
	600	LOG("Failed to set NBD socket");
	601	return -serrno;
	602	}
	603
	604	TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);
	605
	606	if (ioctl(fd, NBD_SET_BLKSIZE, (size_t)BDRV_SECTOR_SIZE) < 0) {
	607	int serrno = errno;
	608	LOG("Failed setting NBD block size");
	609	return -serrno;
	610	}
	611
	612	TRACE("Setting size to %zd block(s)", (size_t)(size / BDRV_SECTOR_SIZE));
	613
	614	if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0) {
	615	int serrno = errno;
	616	LOG("Failed setting size (in blocks)");
	617	return -serrno;
	618	}
	619
	620	if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
	621	if (errno == ENOTTY) {
	622	int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
	623	TRACE("Setting readonly attribute");
	624
	625	if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
	626	int serrno = errno;
	627	LOG("Failed setting read-only attribute");
	628	return -serrno;
	629	}
	630	} else {
	631	int serrno = errno;
	632	LOG("Failed setting flags");
	633	return -serrno;
	634	}
	635	}
	636
	637	TRACE("Negotiation ended");
	638
	639	return 0;
	640	}
	641
	642	int nbd_client(int fd)
	643	{
	644	int ret;
	645	int serrno;
	646
	647	TRACE("Doing NBD loop");
	648
	649	ret = ioctl(fd, NBD_DO_IT);
	650	if (ret < 0 && errno == EPIPE) {
	651	/* NBD_DO_IT normally returns EPIPE when someone has disconnected
	652	* the socket via NBD_DISCONNECT. We do not want to return 1 in
	653	* that case.
	654	*/
	655	ret = 0;
	656	}
	657	serrno = errno;
	658
	659	TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
	660
	661	TRACE("Clearing NBD queue");
	662	ioctl(fd, NBD_CLEAR_QUE);
663
664	TRACE("Clearing NBD socket");
665	ioctl(fd, NBD_CLEAR_SOCK);
666
667	errno = serrno;
668	return ret;
669	}
98494e3b EB	670
	671	int nbd_disconnect(int fd)
	672	{
	673	ioctl(fd, NBD_CLEAR_QUE);
	674	ioctl(fd, NBD_DISCONNECT);
	675	ioctl(fd, NBD_CLEAR_SOCK);
	676	return 0;
	677	}
	678
798bfe00	679	#else
1c778ef7	680	int nbd_init(int fd, QIOChannelSocket *ioc, uint32_t flags, off_t size)
798bfe00 FZ	681	{
	682	return -ENOTSUP;
	683	}
	684
	685	int nbd_client(int fd)
	686	{
	687	return -ENOTSUP;
	688	}
98494e3b EB	689	int nbd_disconnect(int fd)
	690	{
	691	return -ENOTSUP;
	692	}
798bfe00 FZ	693	#endif
798bfe00 FZ	694
1c778ef7	695	ssize_t nbd_send_request(QIOChannel ioc, struct nbd_request request)
798bfe00 FZ	696	{
	697	uint8_t buf[NBD_REQUEST_SIZE];
	698	ssize_t ret;
	699
7548fe31	700	TRACE("Sending request to server: "
2cb34749 EB	701	"{ .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64
2cb34749 EB	702	", .type=%" PRIu16 " }",
7548fe31 EB	703	request->from, request->len, request->handle, request->type);
7548fe31 EB	704
f6be6720 PM	705	stl_be_p(buf, NBD_REQUEST_MAGIC);
	706	stl_be_p(buf + 4, request->type);
	707	stq_be_p(buf + 8, request->handle);
	708	stq_be_p(buf + 16, request->from);
	709	stl_be_p(buf + 24, request->len);
798bfe00	710
1c778ef7	711	ret = write_sync(ioc, buf, sizeof(buf));
798bfe00 FZ	712	if (ret < 0) {
	713	return ret;
	714	}
	715
	716	if (ret != sizeof(buf)) {
	717	LOG("writing to socket failed");
	718	return -EINVAL;
	719	}
	720	return 0;
	721	}
	722
1c778ef7	723	ssize_t nbd_receive_reply(QIOChannel ioc, struct nbd_reply reply)
798bfe00 FZ	724	{
	725	uint8_t buf[NBD_REPLY_SIZE];
	726	uint32_t magic;
	727	ssize_t ret;
	728
1c778ef7	729	ret = read_sync(ioc, buf, sizeof(buf));
798bfe00 FZ	730	if (ret < 0) {
	731	return ret;
	732	}
	733
	734	if (ret != sizeof(buf)) {
	735	LOG("read failed");
	736	return -EINVAL;
	737	}
	738
	739	/* Reply
	740	[ 0 .. 3] magic (NBD_REPLY_MAGIC)
	741	[ 4 .. 7] error (0 == no error)
	742	[ 7 .. 15] handle
	743	*/
	744
773dce3c PM	745	magic = ldl_be_p(buf);
	746	reply->error = ldl_be_p(buf + 4);
	747	reply->handle = ldq_be_p(buf + 8);
798bfe00 FZ	748
	749	reply->error = nbd_errno_to_system_errno(reply->error);
	750
2cb34749 EB	751	TRACE("Got reply: { magic = 0x%" PRIx32 ", .error = % " PRId32
2cb34749 EB	752	", handle = %" PRIu64" }",
798bfe00 FZ	753	magic, reply->error, reply->handle);
	754
	755	if (magic != NBD_REPLY_MAGIC) {
2cb34749	756	LOG("invalid magic (got 0x%" PRIx32 ")", magic);
798bfe00 FZ	757	return -EINVAL;
	758	}
	759	return 0;
	760	}
	761