blockdev-nbd.c

   1 /*
   2  * Serving QEMU block devices via NBD
   3  *
   4  * Copyright (c) 2012 Red Hat, Inc.
   5  *
   6  * Author: Paolo Bonzini <pbonzini@redhat.com>
   7  *
   8  * This work is licensed under the terms of the GNU GPL, version 2 or
   9  * later.  See the COPYING file in the top-level directory.
  10  */
  11
  12 #include "qemu/osdep.h"
  13 #include "sysemu/blockdev.h"
  14 #include "sysemu/block-backend.h"
  15 #include "hw/block/block.h"
  16 #include "qapi/error.h"
  17 #include "qapi/qapi-commands-block.h"
  18 #include "sysemu/sysemu.h"
  19 #include "block/nbd.h"
  20 #include "io/channel-socket.h"
  21 #include "io/net-listener.h"
  22
  23 typedef struct NBDServerData {
  24     QIONetListener *listener;
  25     QCryptoTLSCreds *tlscreds;
  26     char *tlsauthz;
  27 } NBDServerData;
  28
  29 static NBDServerData *nbd_server;
  30
  31 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored)
  32 {
  33     nbd_client_put(client);
  34 }
  35
  36 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc,
  37                        gpointer opaque)
  38 {
  39     qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server");
  40     nbd_client_new(cioc, nbd_server->tlscreds, nbd_server->tlsauthz,
  41                    nbd_blockdev_client_closed);
  42 }
  43
  44
  45 static void nbd_server_free(NBDServerData *server)
  46 {
  47     if (!server) {
  48         return;
  49     }
  50
  51     qio_net_listener_disconnect(server->listener);
  52     object_unref(OBJECT(server->listener));
  53     if (server->tlscreds) {
  54         object_unref(OBJECT(server->tlscreds));
  55     }
  56     g_free(server->tlsauthz);
  57
  58     g_free(server);
  59 }
  60
  61 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
  62 {
  63     Object *obj;
  64     QCryptoTLSCreds *creds;
  65
  66     obj = object_resolve_path_component(
  67         object_get_objects_root(), id);
  68     if (!obj) {
  69         error_setg(errp, "No TLS credentials with id '%s'",
  70                    id);
  71         return NULL;
  72     }
  73     creds = (QCryptoTLSCreds *)
  74         object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS);
  75     if (!creds) {
  76         error_setg(errp, "Object with id '%s' is not TLS credentials",
  77                    id);
  78         return NULL;
  79     }
  80
  81     if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
  82         error_setg(errp,
  83                    "Expecting TLS credentials with a server endpoint");
  84         return NULL;
  85     }
  86     object_ref(obj);
  87     return creds;
  88 }
  89
  90
  91 void nbd_server_start(SocketAddress *addr, const char *tls_creds,
  92                       const char *tls_authz, Error **errp)
  93 {
  94     if (nbd_server) {
  95         error_setg(errp, "NBD server already running");
  96         return;
  97     }
  98
  99     nbd_server = g_new0(NBDServerData, 1);
 100     nbd_server->listener = qio_net_listener_new();
 101
 102     qio_net_listener_set_name(nbd_server->listener,
 103                               "nbd-listener");
 104
 105     if (qio_net_listener_open_sync(nbd_server->listener, addr, errp) < 0) {
 106         goto error;
 107     }
 108
 109     if (tls_creds) {
 110         nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp);
 111         if (!nbd_server->tlscreds) {
 112             goto error;
 113         }
 114
 115         /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */
 116         if (addr->type != SOCKET_ADDRESS_TYPE_INET) {
 117             error_setg(errp, "TLS is only supported with IPv4/IPv6");
 118             goto error;
 119         }
 120     }
 121
 122     nbd_server->tlsauthz = g_strdup(tls_authz);
 123
 124     qio_net_listener_set_client_func(nbd_server->listener,
 125                                      nbd_accept,
 126                                      NULL,
 127                                      NULL);
 128
 129     return;
 130
 131  error:
 132     nbd_server_free(nbd_server);
 133     nbd_server = NULL;
 134 }
 135
 136 void qmp_nbd_server_start(SocketAddressLegacy *addr,
 137                           bool has_tls_creds, const char *tls_creds,
 138                           bool has_tls_authz, const char *tls_authz,
 139                           Error **errp)
 140 {
 141     SocketAddress *addr_flat = socket_address_flatten(addr);
 142
 143     nbd_server_start(addr_flat, tls_creds, tls_authz, errp);
 144     qapi_free_SocketAddress(addr_flat);
 145 }
 146
 147 void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
 148                         bool has_writable, bool writable,
 149                         bool has_bitmap, const char *bitmap, Error **errp)
 150 {
 151     BlockDriverState *bs = NULL;
 152     BlockBackend *on_eject_blk;
 153     NBDExport *exp;
 154     int64_t len;
 155
 156     if (!nbd_server) {
 157         error_setg(errp, "NBD server not running");
 158         return;
 159     }
 160
 161     if (!has_name) {
 162         name = device;
 163     }
 164
 165     if (nbd_export_find(name)) {
 166         error_setg(errp, "NBD server already has export named '%s'", name);
 167         return;
 168     }
 169
 170     on_eject_blk = blk_by_name(device);
 171
 172     bs = bdrv_lookup_bs(device, device, errp);
 173     if (!bs) {
 174         return;
 175     }
 176
 177     len = bdrv_getlength(bs);
 178     if (len < 0) {
 179         error_setg_errno(errp, -len,
 180                          "Failed to determine the NBD export's length");
 181         return;
 182     }
 183
 184     if (!has_writable) {
 185         writable = false;
 186     }
 187     if (bdrv_is_read_only(bs)) {
 188         writable = false;
 189     }
 190
 191     exp = nbd_export_new(bs, 0, len, name, NULL, bitmap,
 192                          writable ? 0 : NBD_FLAG_READ_ONLY,
 193                          NULL, false, on_eject_blk, errp);
 194     if (!exp) {
 195         return;
 196     }
 197
 198     /* The list of named exports has a strong reference to this export now and
 199      * our only way of accessing it is through nbd_export_find(), so we can drop
 200      * the strong reference that is @exp. */
 201     nbd_export_put(exp);
 202 }
 203
 204 void qmp_nbd_server_remove(const char *name,
 205                            bool has_mode, NbdServerRemoveMode mode,
 206                            Error **errp)
 207 {
 208     NBDExport *exp;
 209
 210     if (!nbd_server) {
 211         error_setg(errp, "NBD server not running");
 212         return;
 213     }
 214
 215     exp = nbd_export_find(name);
 216     if (exp == NULL) {
 217         error_setg(errp, "Export '%s' is not found", name);
 218         return;
 219     }
 220
 221     if (!has_mode) {
 222         mode = NBD_SERVER_REMOVE_MODE_SAFE;
 223     }
 224
 225     nbd_export_remove(exp, mode, errp);
 226 }
 227
 228 void qmp_nbd_server_stop(Error **errp)
 229 {
 230     if (!nbd_server) {
 231         error_setg(errp, "NBD server not running");
 232         return;
 233     }
 234
 235     nbd_export_close_all();
 236
 237     nbd_server_free(nbd_server);
 238     nbd_server = NULL;
 239 }