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/qmp/qerror.h" 17 #include "sysemu/sysemu.h" 18 #include "qmp-commands.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 } NBDServerData; 27 28 static NBDServerData *nbd_server; 29 30 static void nbd_blockdev_client_closed(NBDClient *client, bool ignored) 31 { 32 nbd_client_put(client); 33 } 34 35 static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc, 36 gpointer opaque) 37 { 38 qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server"); 39 nbd_client_new(NULL, cioc, 40 nbd_server->tlscreds, NULL, 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 57 g_free(server); 58 } 59 60 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) 61 { 62 Object *obj; 63 QCryptoTLSCreds *creds; 64 65 obj = object_resolve_path_component( 66 object_get_objects_root(), id); 67 if (!obj) { 68 error_setg(errp, "No TLS credentials with id '%s'", 69 id); 70 return NULL; 71 } 72 creds = (QCryptoTLSCreds *) 73 object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS); 74 if (!creds) { 75 error_setg(errp, "Object with id '%s' is not TLS credentials", 76 id); 77 return NULL; 78 } 79 80 if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { 81 error_setg(errp, 82 "Expecting TLS credentials with a server endpoint"); 83 return NULL; 84 } 85 object_ref(obj); 86 return creds; 87 } 88 89 90 void nbd_server_start(SocketAddress *addr, const char *tls_creds, 91 Error **errp) 92 { 93 if (nbd_server) { 94 error_setg(errp, "NBD server already running"); 95 return; 96 } 97 98 nbd_server = g_new0(NBDServerData, 1); 99 nbd_server->listener = qio_net_listener_new(); 100 101 qio_net_listener_set_name(nbd_server->listener, 102 "nbd-listener"); 103 104 if (qio_net_listener_open_sync(nbd_server->listener, addr, errp) < 0) { 105 goto error; 106 } 107 108 if (tls_creds) { 109 nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp); 110 if (!nbd_server->tlscreds) { 111 goto error; 112 } 113 114 /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */ 115 if (addr->type != SOCKET_ADDRESS_TYPE_INET) { 116 error_setg(errp, "TLS is only supported with IPv4/IPv6"); 117 goto error; 118 } 119 } 120 121 qio_net_listener_set_client_func(nbd_server->listener, 122 nbd_accept, 123 NULL, 124 NULL); 125 126 return; 127 128 error: 129 nbd_server_free(nbd_server); 130 nbd_server = NULL; 131 } 132 133 void qmp_nbd_server_start(SocketAddressLegacy *addr, 134 bool has_tls_creds, const char *tls_creds, 135 Error **errp) 136 { 137 SocketAddress *addr_flat = socket_address_flatten(addr); 138 139 nbd_server_start(addr_flat, tls_creds, errp); 140 qapi_free_SocketAddress(addr_flat); 141 } 142 143 void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, 144 Error **errp) 145 { 146 BlockDriverState *bs = NULL; 147 BlockBackend *on_eject_blk; 148 NBDExport *exp; 149 150 if (!nbd_server) { 151 error_setg(errp, "NBD server not running"); 152 return; 153 } 154 155 if (nbd_export_find(device)) { 156 error_setg(errp, "NBD server already exporting device '%s'", device); 157 return; 158 } 159 160 on_eject_blk = blk_by_name(device); 161 162 bs = bdrv_lookup_bs(device, device, errp); 163 if (!bs) { 164 return; 165 } 166 167 if (!has_writable) { 168 writable = false; 169 } 170 if (bdrv_is_read_only(bs)) { 171 writable = false; 172 } 173 174 exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, 175 NULL, false, on_eject_blk, errp); 176 if (!exp) { 177 return; 178 } 179 180 nbd_export_set_name(exp, device); 181 182 /* The list of named exports has a strong reference to this export now and 183 * our only way of accessing it is through nbd_export_find(), so we can drop 184 * the strong reference that is @exp. */ 185 nbd_export_put(exp); 186 } 187 188 void qmp_nbd_server_stop(Error **errp) 189 { 190 nbd_export_close_all(); 191 192 nbd_server_free(nbd_server); 193 nbd_server = NULL; 194 } 195