[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 %d, attempting fallback",
              opt);
        result = 0;
        goto cleanup;

    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;
    }

    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 %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);
    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 (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;

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

    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);

    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 <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:
6ff58164 AB	112	TRACE("server doesn't understand request %d, attempting fallback",
	113	opt);
	114	result = 0;
	115	goto cleanup;
9344e5f5	116
f95910fe DB	117	case NBD_REP_ERR_POLICY:
	118	error_setg(errp, "Denied by server for option %x", opt);
	119	break;
	120
9344e5f5 DB	121	case NBD_REP_ERR_INVALID:
	122	error_setg(errp, "Invalid data length for option %x", opt);
	123	break;
	124
f95910fe DB	125	case NBD_REP_ERR_TLS_REQD:
	126	error_setg(errp, "TLS negotiation required before option %x", opt);
	127	break;
	128
9344e5f5 DB	129	default:
	130	error_setg(errp, "Unknown error code when asking for option %x", opt);
	131	break;
	132	}
	133
6ff58164 AB	134	if (msg) {
	135	error_append_hint(errp, "%s\n", msg);
	136	}
	137
	138	cleanup:
	139	g_free(msg);
	140	return result;
9344e5f5 DB	141	}
	142
	143	static int nbd_receive_list(QIOChannel ioc, char name, Error *errp)
	144	{
	145	uint64_t magic;
	146	uint32_t opt;
	147	uint32_t type;
	148	uint32_t len;
	149	uint32_t namelen;
6ff58164	150	int error;
9344e5f5 DB	151
	152	*name = NULL;
	153	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	154	error_setg(errp, "failed to read list option magic");
	155	return -1;
	156	}
	157	magic = be64_to_cpu(magic);
	158	if (magic != NBD_REP_MAGIC) {
	159	error_setg(errp, "Unexpected option list magic");
	160	return -1;
	161	}
	162	if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	163	error_setg(errp, "failed to read list option");
	164	return -1;
	165	}
	166	opt = be32_to_cpu(opt);
	167	if (opt != NBD_OPT_LIST) {
	168	error_setg(errp, "Unexpected option type %x expected %x",
	169	opt, NBD_OPT_LIST);
	170	return -1;
	171	}
	172
	173	if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
	174	error_setg(errp, "failed to read list option type");
	175	return -1;
	176	}
	177	type = be32_to_cpu(type);
6ff58164 AB	178	error = nbd_handle_reply_err(ioc, opt, type, errp);
	179	if (error <= 0) {
	180	return error;
9344e5f5 DB	181	}
	182
	183	if (read_sync(ioc, &len, sizeof(len)) != sizeof(len)) {
	184	error_setg(errp, "failed to read option length");
	185	return -1;
	186	}
	187	len = be32_to_cpu(len);
	188
	189	if (type == NBD_REP_ACK) {
	190	if (len != 0) {
	191	error_setg(errp, "length too long for option end");
	192	return -1;
	193	}
	194	} else if (type == NBD_REP_SERVER) {
	195	if (read_sync(ioc, &namelen, sizeof(namelen)) != sizeof(namelen)) {
	196	error_setg(errp, "failed to read option name length");
	197	return -1;
	198	}
	199	namelen = be32_to_cpu(namelen);
	200	if (len != (namelen + sizeof(namelen))) {
	201	error_setg(errp, "incorrect option mame length");
	202	return -1;
	203	}
	204	if (namelen > 255) {
	205	error_setg(errp, "export name length too long %d", namelen);
	206	return -1;
	207	}
	208
	209	*name = g_new0(char, namelen + 1);
	210	if (read_sync(ioc, *name, namelen) != namelen) {
	211	error_setg(errp, "failed to read export name");
	212	g_free(*name);
	213	*name = NULL;
	214	return -1;
	215	}
	216	(*name)[namelen] = '\0';
	217	} else {
	218	error_setg(errp, "Unexpected reply type %x expected %x",
	219	type, NBD_REP_SERVER);
	220	return -1;
	221	}
	222	return 1;
	223	}
	224
	225
	226	static int nbd_receive_query_exports(QIOChannel *ioc,
	227	const char *wantname,
	228	Error **errp)
	229	{
	230	uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
	231	uint32_t opt = cpu_to_be32(NBD_OPT_LIST);
	232	uint32_t length = 0;
	233	bool foundExport = false;
	234
	235	TRACE("Querying export list");
	236	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	237	error_setg(errp, "Failed to send list option magic");
	238	return -1;
	239	}
	240
	241	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	242	error_setg(errp, "Failed to send list option number");
	243	return -1;
	244	}
245
246	if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
247	error_setg(errp, "Failed to send list option length");
248	return -1;
249	}
250
251	TRACE("Reading available export names");
252	while (1) {
253	char *name = NULL;
254	int ret = nbd_receive_list(ioc, &name, errp);
255
256	if (ret < 0) {
257	g_free(name);
258	name = NULL;
259	return -1;
260	}
261	if (ret == 0) {
262	/* Server doesn't support export listing, so
263	* we will just assume an export with our
264	* wanted name exists */
265	foundExport = true;
266	break;
267	}
268	if (name == NULL) {
269	TRACE("End of export name list");
270	break;
271	}
272	if (g_str_equal(name, wantname)) {
273	foundExport = true;
274	TRACE("Found desired export name '%s'", name);
275	} else {
276	TRACE("Ignored export name '%s'", name);
277	}
278	g_free(name);
279	}
280
281	if (!foundExport) {
282	error_setg(errp, "No export with name '%s' available", wantname);
283	return -1;
284	}
285
286	return 0;
287	}
288
f95910fe DB	289	static QIOChannel nbd_receive_starttls(QIOChannel ioc,
	290	QCryptoTLSCreds *tlscreds,
	291	const char hostname, Error *errp)
	292	{
	293	uint64_t magic = cpu_to_be64(NBD_OPTS_MAGIC);
	294	uint32_t opt = cpu_to_be32(NBD_OPT_STARTTLS);
	295	uint32_t length = 0;
	296	uint32_t type;
	297	QIOChannelTLS *tioc;
	298	struct NBDTLSHandshakeData data = { 0 };
	299
	300	TRACE("Requesting TLS from server");
	301	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	302	error_setg(errp, "Failed to send option magic");
	303	return NULL;
	304	}
	305
	306	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	307	error_setg(errp, "Failed to send option number");
	308	return NULL;
	309	}
	310
	311	if (write_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
	312	error_setg(errp, "Failed to send option length");
	313	return NULL;
	314	}
	315
	316	TRACE("Getting TLS reply from server1");
	317	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
	318	error_setg(errp, "failed to read option magic");
	319	return NULL;
	320	}
	321	magic = be64_to_cpu(magic);
	322	if (magic != NBD_REP_MAGIC) {
	323	error_setg(errp, "Unexpected option magic");
	324	return NULL;
	325	}
	326	TRACE("Getting TLS reply from server2");
	327	if (read_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
	328	error_setg(errp, "failed to read option");
	329	return NULL;
	330	}
	331	opt = be32_to_cpu(opt);
	332	if (opt != NBD_OPT_STARTTLS) {
	333	error_setg(errp, "Unexpected option type %x expected %x",
	334	opt, NBD_OPT_STARTTLS);
	335	return NULL;
	336	}
	337
	338	TRACE("Getting TLS reply from server");
	339	if (read_sync(ioc, &type, sizeof(type)) != sizeof(type)) {
	340	error_setg(errp, "failed to read option type");
	341	return NULL;
	342	}
	343	type = be32_to_cpu(type);
	344	if (type != NBD_REP_ACK) {
	345	error_setg(errp, "Server rejected request to start TLS %x",
	346	type);
	347	return NULL;
	348	}
	349
	350	TRACE("Getting TLS reply from server");
	351	if (read_sync(ioc, &length, sizeof(length)) != sizeof(length)) {
	352	error_setg(errp, "failed to read option length");
353	return NULL;
354	}
355	length = be32_to_cpu(length);
356	if (length != 0) {
357	error_setg(errp, "Start TLS reponse was not zero %x",
358	length);
359	return NULL;
360	}
361
362	TRACE("TLS request approved, setting up TLS");
363	tioc = qio_channel_tls_new_client(ioc, tlscreds, hostname, errp);
364	if (!tioc) {
365	return NULL;
366	}
367	data.loop = g_main_loop_new(g_main_context_default(), FALSE);
368	TRACE("Starting TLS hanshake");
369	qio_channel_tls_handshake(tioc,
370	nbd_tls_handshake,
371	&data,
372	NULL);
373
374	if (!data.complete) {
375	g_main_loop_run(data.loop);
376	}
377	g_main_loop_unref(data.loop);
378	if (data.error) {
379	error_propagate(errp, data.error);
380	object_unref(OBJECT(tioc));
381	return NULL;
382	}
383
384	return QIO_CHANNEL(tioc);
385	}
386
387
1c778ef7	388	int nbd_receive_negotiate(QIOChannel ioc, const char name, uint32_t *flags,
f95910fe DB	389	QCryptoTLSCreds tlscreds, const char hostname,
f95910fe DB	390	QIOChannel **outioc,
798bfe00 FZ	391	off_t size, Error *errp)
	392	{
	393	char buf[256];
	394	uint64_t magic, s;
798bfe00 FZ	395	int rc;
798bfe00 FZ	396
f95910fe DB	397	TRACE("Receiving negotiation tlscreds=%p hostname=%s.",
f95910fe DB	398	tlscreds, hostname ? hostname : "<null>");
798bfe00 FZ	399
	400	rc = -EINVAL;
	401
f95910fe DB	402	if (outioc) {
	403	*outioc = NULL;
	404	}
	405	if (tlscreds && !outioc) {
	406	error_setg(errp, "Output I/O channel required for TLS");
	407	goto fail;
	408	}
	409
1c778ef7	410	if (read_sync(ioc, buf, 8) != 8) {
798bfe00 FZ	411	error_setg(errp, "Failed to read data");
	412	goto fail;
	413	}
	414
	415	buf[8] = '\0';
	416	if (strlen(buf) == 0) {
	417	error_setg(errp, "Server connection closed unexpectedly");
	418	goto fail;
	419	}
	420
	421	TRACE("Magic is %c%c%c%c%c%c%c%c",
	422	qemu_isprint(buf[0]) ? buf[0] : '.',
	423	qemu_isprint(buf[1]) ? buf[1] : '.',
	424	qemu_isprint(buf[2]) ? buf[2] : '.',
	425	qemu_isprint(buf[3]) ? buf[3] : '.',
	426	qemu_isprint(buf[4]) ? buf[4] : '.',
	427	qemu_isprint(buf[5]) ? buf[5] : '.',
	428	qemu_isprint(buf[6]) ? buf[6] : '.',
	429	qemu_isprint(buf[7]) ? buf[7] : '.');
	430
	431	if (memcmp(buf, "NBDMAGIC", 8) != 0) {
	432	error_setg(errp, "Invalid magic received");
	433	goto fail;
	434	}
	435
1c778ef7	436	if (read_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
798bfe00 FZ	437	error_setg(errp, "Failed to read magic");
	438	goto fail;
	439	}
	440	magic = be64_to_cpu(magic);
	441	TRACE("Magic is 0x%" PRIx64, magic);
	442
f72d705f	443	if (magic == NBD_OPTS_MAGIC) {
e2a9d9a3	444	uint32_t clientflags = 0;
798bfe00 FZ	445	uint32_t opt;
798bfe00 FZ	446	uint32_t namesize;
e2a9d9a3 DB	447	uint16_t globalflags;
e2a9d9a3 DB	448	uint16_t exportflags;
9344e5f5	449	bool fixedNewStyle = false;
798bfe00	450
e2a9d9a3 DB	451	if (read_sync(ioc, &globalflags, sizeof(globalflags)) !=
e2a9d9a3 DB	452	sizeof(globalflags)) {
798bfe00 FZ	453	error_setg(errp, "Failed to read server flags");
	454	goto fail;
	455	}
9344e5f5 DB	456	globalflags = be16_to_cpu(globalflags);
	457	*flags = globalflags << 16;
	458	TRACE("Global flags are %x", globalflags);
e2a9d9a3	459	if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
9344e5f5	460	fixedNewStyle = true;
e2a9d9a3 DB	461	TRACE("Server supports fixed new style");
	462	clientflags \|= NBD_FLAG_C_FIXED_NEWSTYLE;
	463	}
	464	/* client requested flags */
9344e5f5	465	clientflags = cpu_to_be32(clientflags);
e2a9d9a3 DB	466	if (write_sync(ioc, &clientflags, sizeof(clientflags)) !=
	467	sizeof(clientflags)) {
	468	error_setg(errp, "Failed to send clientflags field");
798bfe00 FZ	469	goto fail;
798bfe00 FZ	470	}
f95910fe DB	471	if (tlscreds) {
	472	if (fixedNewStyle) {
	473	*outioc = nbd_receive_starttls(ioc, tlscreds, hostname, errp);
	474	if (!*outioc) {
	475	goto fail;
	476	}
	477	ioc = *outioc;
	478	} else {
	479	error_setg(errp, "Server does not support STARTTLS");
	480	goto fail;
	481	}
	482	}
f72d705f	483	if (!name) {
69b49502 DB	484	TRACE("Using default NBD export name \"\"");
69b49502 DB	485	name = "";
f72d705f	486	}
9344e5f5 DB	487	if (fixedNewStyle) {
	488	/* Check our desired export is present in the
	489	* server export list. Since NBD_OPT_EXPORT_NAME
	490	* cannot return an error message, running this
	491	* query gives us good error reporting if the
	492	* server required TLS
	493	*/
	494	if (nbd_receive_query_exports(ioc, name, errp) < 0) {
	495	goto fail;
	496	}
	497	}
	498	/* write the export name */
798bfe00	499	magic = cpu_to_be64(magic);
1c778ef7	500	if (write_sync(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
798bfe00 FZ	501	error_setg(errp, "Failed to send export name magic");
	502	goto fail;
	503	}
	504	opt = cpu_to_be32(NBD_OPT_EXPORT_NAME);
1c778ef7	505	if (write_sync(ioc, &opt, sizeof(opt)) != sizeof(opt)) {
798bfe00 FZ	506	error_setg(errp, "Failed to send export name option number");
	507	goto fail;
	508	}
	509	namesize = cpu_to_be32(strlen(name));
1c778ef7	510	if (write_sync(ioc, &namesize, sizeof(namesize)) !=
798bfe00 FZ	511	sizeof(namesize)) {
	512	error_setg(errp, "Failed to send export name length");
	513	goto fail;
	514	}
1c778ef7	515	if (write_sync(ioc, (char *)name, strlen(name)) != strlen(name)) {
798bfe00 FZ	516	error_setg(errp, "Failed to send export name");
	517	goto fail;
	518	}
f72d705f DB	519
	520	if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
	521	error_setg(errp, "Failed to read export length");
798bfe00 FZ	522	goto fail;
798bfe00 FZ	523	}
f72d705f DB	524	*size = be64_to_cpu(s);
f72d705f DB	525	TRACE("Size is %" PRIu64, *size);
798bfe00	526
e2a9d9a3 DB	527	if (read_sync(ioc, &exportflags, sizeof(exportflags)) !=
e2a9d9a3 DB	528	sizeof(exportflags)) {
f72d705f DB	529	error_setg(errp, "Failed to read export flags");
	530	goto fail;
	531	}
9344e5f5 DB	532	exportflags = be16_to_cpu(exportflags);
	533	*flags \|= exportflags;
	534	TRACE("Export flags are %x", exportflags);
f72d705f DB	535	} else if (magic == NBD_CLIENT_MAGIC) {
	536	if (name) {
	537	error_setg(errp, "Server does not support export names");
	538	goto fail;
	539	}
f95910fe DB	540	if (tlscreds) {
	541	error_setg(errp, "Server does not support STARTTLS");
	542	goto fail;
	543	}
f72d705f DB	544
	545	if (read_sync(ioc, &s, sizeof(s)) != sizeof(s)) {
	546	error_setg(errp, "Failed to read export length");
	547	goto fail;
	548	}
	549	*size = be64_to_cpu(s);
	550	TRACE("Size is %" PRIu64, *size);
798bfe00	551
1c778ef7	552	if (read_sync(ioc, flags, sizeof(flags)) != sizeof(flags)) {
798bfe00 FZ	553	error_setg(errp, "Failed to read export flags");
	554	goto fail;
	555	}
	556	*flags = be32_to_cpup(flags);
	557	} else {
f72d705f DB	558	error_setg(errp, "Bad magic received");
f72d705f DB	559	goto fail;
798bfe00	560	}
f72d705f	561
1c778ef7	562	if (read_sync(ioc, &buf, 124) != 124) {
798bfe00 FZ	563	error_setg(errp, "Failed to read reserved block");
	564	goto fail;
	565	}
	566	rc = 0;
	567
	568	fail:
	569	return rc;
	570	}
	571
	572	#ifdef __linux__
1c778ef7	573	int nbd_init(int fd, QIOChannelSocket *sioc, uint32_t flags, off_t size)
798bfe00 FZ	574	{
	575	TRACE("Setting NBD socket");
	576
1c778ef7	577	if (ioctl(fd, NBD_SET_SOCK, sioc->fd) < 0) {
798bfe00 FZ	578	int serrno = errno;
	579	LOG("Failed to set NBD socket");
	580	return -serrno;
	581	}
	582
	583	TRACE("Setting block size to %lu", (unsigned long)BDRV_SECTOR_SIZE);
	584
	585	if (ioctl(fd, NBD_SET_BLKSIZE, (size_t)BDRV_SECTOR_SIZE) < 0) {
	586	int serrno = errno;
	587	LOG("Failed setting NBD block size");
	588	return -serrno;
	589	}
	590
	591	TRACE("Setting size to %zd block(s)", (size_t)(size / BDRV_SECTOR_SIZE));
	592
	593	if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0) {
	594	int serrno = errno;
	595	LOG("Failed setting size (in blocks)");
	596	return -serrno;
	597	}
	598
	599	if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
	600	if (errno == ENOTTY) {
	601	int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
	602	TRACE("Setting readonly attribute");
	603
	604	if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
	605	int serrno = errno;
	606	LOG("Failed setting read-only attribute");
	607	return -serrno;
	608	}
	609	} else {
	610	int serrno = errno;
	611	LOG("Failed setting flags");
	612	return -serrno;
	613	}
	614	}
	615
	616	TRACE("Negotiation ended");
	617
	618	return 0;
	619	}
	620
	621	int nbd_client(int fd)
	622	{
	623	int ret;
	624	int serrno;
	625
	626	TRACE("Doing NBD loop");
	627
	628	ret = ioctl(fd, NBD_DO_IT);
	629	if (ret < 0 && errno == EPIPE) {
	630	/* NBD_DO_IT normally returns EPIPE when someone has disconnected
	631	* the socket via NBD_DISCONNECT. We do not want to return 1 in
	632	* that case.
	633	*/
	634	ret = 0;
	635	}
	636	serrno = errno;
	637
	638	TRACE("NBD loop returned %d: %s", ret, strerror(serrno));
	639
	640	TRACE("Clearing NBD queue");
	641	ioctl(fd, NBD_CLEAR_QUE);
642
643	TRACE("Clearing NBD socket");
644	ioctl(fd, NBD_CLEAR_SOCK);
645
646	errno = serrno;
647	return ret;
648	}
649	#else
1c778ef7	650	int nbd_init(int fd, QIOChannelSocket *ioc, uint32_t flags, off_t size)
798bfe00 FZ	651	{
	652	return -ENOTSUP;
	653	}
	654
	655	int nbd_client(int fd)
	656	{
	657	return -ENOTSUP;
	658	}
	659	#endif
	660
1c778ef7	661	ssize_t nbd_send_request(QIOChannel ioc, struct nbd_request request)
798bfe00 FZ	662	{
	663	uint8_t buf[NBD_REQUEST_SIZE];
	664	ssize_t ret;
	665
7548fe31 EB	666	TRACE("Sending request to server: "
	667	"{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
	668	request->from, request->len, request->handle, request->type);
	669
798bfe00 FZ	670	cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
	671	cpu_to_be32w((uint32_t*)(buf + 4), request->type);
	672	cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
	673	cpu_to_be64w((uint64_t*)(buf + 16), request->from);
	674	cpu_to_be32w((uint32_t*)(buf + 24), request->len);
	675
1c778ef7	676	ret = write_sync(ioc, buf, sizeof(buf));
798bfe00 FZ	677	if (ret < 0) {
	678	return ret;
	679	}
	680
	681	if (ret != sizeof(buf)) {
	682	LOG("writing to socket failed");
	683	return -EINVAL;
	684	}
	685	return 0;
	686	}
	687
1c778ef7	688	ssize_t nbd_receive_reply(QIOChannel ioc, struct nbd_reply reply)
798bfe00 FZ	689	{
	690	uint8_t buf[NBD_REPLY_SIZE];
	691	uint32_t magic;
	692	ssize_t ret;
	693
1c778ef7	694	ret = read_sync(ioc, buf, sizeof(buf));
798bfe00 FZ	695	if (ret < 0) {
	696	return ret;
	697	}
	698
	699	if (ret != sizeof(buf)) {
	700	LOG("read failed");
	701	return -EINVAL;
	702	}
	703
	704	/* Reply
	705	[ 0 .. 3] magic (NBD_REPLY_MAGIC)
	706	[ 4 .. 7] error (0 == no error)
	707	[ 7 .. 15] handle
	708	*/
	709
	710	magic = be32_to_cpup((uint32_t*)buf);
	711	reply->error = be32_to_cpup((uint32_t*)(buf + 4));
	712	reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
	713
	714	reply->error = nbd_errno_to_system_errno(reply->error);
	715
	716	TRACE("Got reply: "
	717	"{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
	718	magic, reply->error, reply->handle);
	719
	720	if (magic != NBD_REPLY_MAGIC) {
	721	LOG("invalid magic (got 0x%x)", magic);
	722	return -EINVAL;
	723	}
	724	return 0;
	725	}
	726