Commit f5076b5a authored by Hani Benhabiles's avatar Hani Benhabiles Committed by Paolo Bonzini
Browse files

nbd: Handle fixed new-style clients. 



When this flag is set, the server tells the client that it can send another
option if the server received a request with an option that it doesn't
understand instead of directly closing the connection.

Also add link to the most up-to-date documentation.

Signed-off-by: default avatarHani Benhabiles <kroosec@gmail.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 27e5eae4

include/block/nbd.h

+9 −0
Original line number Diff line number Diff line
@@ -45,6 +45,15 @@ struct nbd_reply { 
#define NBD_FLAG_ROTATIONAL     (1 << 4)        /* Use elevator algorithm - rotational media */

#define NBD_FLAG_SEND_TRIM      (1 << 5)        /* Send TRIM (discard) */



/* New-style global flags. */

#define NBD_FLAG_FIXED_NEWSTYLE     (1 << 0)    /* Fixed newstyle protocol. */



/* New-style client flags. */

#define NBD_FLAG_C_FIXED_NEWSTYLE   (1 << 0)    /* Fixed newstyle protocol. */



/* Reply types. */

#define NBD_REP_ERR_UNSUP       ((1 << 31) | 1) /* Unknown option. */



#define NBD_CMD_MASK_COMMAND	0x0000ffff

#define NBD_CMD_FLAG_FUA	(1 << 16)

nbd.c

+102 −49
Original line number Diff line number Diff line
@@ -56,7 +56,11 @@ 
            __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \

} while(0)



/* This is all part of the "official" NBD API */

/* This is all part of the "official" NBD API.

 *

 * The most up-to-date documentation is available at:

 * https://github.com/yoe/nbd/blob/master/doc/proto.txt

 */



#define NBD_REQUEST_SIZE        (4 + 4 + 8 + 8 + 4)

#define NBD_REPLY_SIZE          (4 + 4 + 8)
@@ -64,6 +68,7 @@ 
#define NBD_REPLY_MAGIC         0x67446698

#define NBD_OPTS_MAGIC          0x49484156454F5054LL

#define NBD_CLIENT_MAGIC        0x0000420281861253LL

#define NBD_REP_MAGIC           0x3e889045565a9LL



#define NBD_SET_SOCK            _IO(0xab, 0)

#define NBD_SET_BLKSIZE         _IO(0xab, 1)
@@ -77,7 +82,8 @@ 
#define NBD_SET_TIMEOUT         _IO(0xab, 9)

#define NBD_SET_FLAGS           _IO(0xab, 10)



#define NBD_OPT_EXPORT_NAME     (1 << 0)

#define NBD_OPT_EXPORT_NAME     (1)

#define NBD_OPT_ABORT           (2)



/* Definitions for opaque data types */
@@ -215,82 +221,128 @@ static ssize_t write_sync(int fd, void *buffer, size_t size) 


*/



static int nbd_send_rep(int csock, uint32_t type, uint32_t opt)

{

    uint64_t magic;

    uint32_t len;



    magic = cpu_to_be64(NBD_REP_MAGIC);

    if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {

        LOG("write failed (rep magic)");

        return -EINVAL;

    }

    opt = cpu_to_be32(opt);

    if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) {

        LOG("write failed (rep opt)");

        return -EINVAL;

    }

    type = cpu_to_be32(type);

    if (write_sync(csock, &type, sizeof(type)) != sizeof(type)) {

        LOG("write failed (rep type)");

        return -EINVAL;

    }

    len = cpu_to_be32(0);

    if (write_sync(csock, &len, sizeof(len)) != sizeof(len)) {

        LOG("write failed (rep data length)");

        return -EINVAL;

    }

    return 0;

}



static int nbd_handle_export_name(NBDClient *client, uint32_t length)

{

    int rc = -EINVAL, csock = client->sock;

    char name[256];



    /* Client sends:

        [20 ..  xx]   export name (length bytes)

     */

    TRACE("Checking length");

    if (length > 255) {

        LOG("Bad length received");

        goto fail;

    }

    if (read_sync(csock, name, length) != length) {

        LOG("read failed");

        goto fail;

    }

    name[length] = '\0';



    client->exp = nbd_export_find(name);

    if (!client->exp) {

        LOG("export not found");

        goto fail;

    }



    QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);

    nbd_export_get(client->exp);

    rc = 0;

fail:

    return rc;

}



static int nbd_receive_options(NBDClient *client)

{

    while (1) {

        int csock = client->sock;

    char name[256];

        uint32_t tmp, length;

        uint64_t magic;

    int rc;



        /* Client sends:

        [ 0 ..   3]   reserved (0)

            [ 0 ..   3]   client flags

            [ 4 ..  11]   NBD_OPTS_MAGIC

        [12 ..  15]   NBD_OPT_EXPORT_NAME

            [12 ..  15]   NBD option

            [16 ..  19]   length

        [20 ..  xx]   export name (length bytes)

            ...           Rest of request

        */



    rc = -EINVAL;

        if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {

            LOG("read failed");

        goto fail;

            return -EINVAL;

        }

    TRACE("Checking reserved");

    if (tmp != 0) {

        LOG("Bad reserved received");

        goto fail;

        TRACE("Checking client flags");

        tmp = be32_to_cpu(tmp);

        if (tmp != 0 && tmp != NBD_FLAG_C_FIXED_NEWSTYLE) {

            LOG("Bad client flags received");

            return -EINVAL;

        }



        if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {

            LOG("read failed");

        goto fail;

            return -EINVAL;

        }

    TRACE("Checking reserved");

        TRACE("Checking opts magic");

        if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {

            LOG("Bad magic received");

        goto fail;

            return -EINVAL;

        }



        if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {

            LOG("read failed");

        goto fail;

    }

    TRACE("Checking option");

    if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) {

        LOG("Bad option received");

        goto fail;

            return -EINVAL;

        }



        if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) {

            LOG("read failed");

        goto fail;

            return -EINVAL;

        }

    TRACE("Checking length");

        length = be32_to_cpu(length);

    if (length > 255) {

        LOG("Bad length received");

        goto fail;

    }

    if (read_sync(csock, name, length) != length) {

        LOG("read failed");

        goto fail;

    }

    name[length] = '\0';



    client->exp = nbd_export_find(name);

    if (!client->exp) {

        LOG("export not found");

        goto fail;

    }

        TRACE("Checking option");

        switch (be32_to_cpu(tmp)) {

        case NBD_OPT_ABORT:

            return -EINVAL;



    QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);

    nbd_export_get(client->exp);

        case NBD_OPT_EXPORT_NAME:

            return nbd_handle_export_name(client, length);



    TRACE("Option negotiation succeeded.");

    rc = 0;

fail:

    return rc;

        default:

            tmp = be32_to_cpu(tmp);

            LOG("Unsupported option 0x%x", tmp);

            nbd_send_rep(client->sock, NBD_REP_ERR_UNSUP, tmp);

            return -EINVAL;

        }

    }

}



static int nbd_send_negotiate(NBDClient *client)
@@ -333,6 +385,7 @@ static int nbd_send_negotiate(NBDClient *client) 
        cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags);

    } else {

        cpu_to_be64w((uint64_t*)(buf + 8), NBD_OPTS_MAGIC);

        cpu_to_be16w((uint16_t *)(buf + 16), NBD_FLAG_FIXED_NEWSTYLE);

    }



    if (client->exp) {
@@ -346,7 +399,7 @@ static int nbd_send_negotiate(NBDClient *client) 
            goto fail;

        }

        rc = nbd_receive_options(client);

        if (rc < 0) {

        if (rc != 0) {

            LOG("option negotiation failed");

            goto fail;

        }
@@ -1174,7 +1227,7 @@ NBDClient *nbd_client_new(NBDExport *exp, int csock, 
    client->refcount = 1;

    client->exp = exp;

    client->sock = csock;

    if (nbd_send_negotiate(client) < 0) {

    if (nbd_send_negotiate(client)) {

        g_free(client);

        return NULL;

    }