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 22 typedef struct NBDServerData { 23 QIOChannelSocket *listen_ioc; 24 int watch; 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 gboolean nbd_accept(QIOChannel *ioc, GIOCondition condition, 36 gpointer opaque) 37 { 38 QIOChannelSocket *cioc; 39 40 if (!nbd_server) { 41 return FALSE; 42 } 43 44 cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc), 45 NULL); 46 if (!cioc) { 47 return TRUE; 48 } 49 50 qio_channel_set_name(QIO_CHANNEL(cioc), "nbd-server"); 51 nbd_client_new(NULL, cioc, 52 nbd_server->tlscreds, NULL, 53 nbd_blockdev_client_closed); 54 object_unref(OBJECT(cioc)); 55 return TRUE; 56 } 57 58 59 static void nbd_server_free(NBDServerData *server) 60 { 61 if (!server) { 62 return; 63 } 64 65 if (server->watch != -1) { 66 g_source_remove(server->watch); 67 } 68 object_unref(OBJECT(server->listen_ioc)); 69 if (server->tlscreds) { 70 object_unref(OBJECT(server->tlscreds)); 71 } 72 73 g_free(server); 74 } 75 76 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) 77 { 78 Object *obj; 79 QCryptoTLSCreds *creds; 80 81 obj = object_resolve_path_component( 82 object_get_objects_root(), id); 83 if (!obj) { 84 error_setg(errp, "No TLS credentials with id '%s'", 85 id); 86 return NULL; 87 } 88 creds = (QCryptoTLSCreds *) 89 object_dynamic_cast(obj, TYPE_QCRYPTO_TLS_CREDS); 90 if (!creds) { 91 error_setg(errp, "Object with id '%s' is not TLS credentials", 92 id); 93 return NULL; 94 } 95 96 if (creds->endpoint != QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { 97 error_setg(errp, 98 "Expecting TLS credentials with a server endpoint"); 99 return NULL; 100 } 101 object_ref(obj); 102 return creds; 103 } 104 105 106 void nbd_server_start(SocketAddress *addr, const char *tls_creds, 107 Error **errp) 108 { 109 if (nbd_server) { 110 error_setg(errp, "NBD server already running"); 111 return; 112 } 113 114 nbd_server = g_new0(NBDServerData, 1); 115 nbd_server->watch = -1; 116 nbd_server->listen_ioc = qio_channel_socket_new(); 117 qio_channel_set_name(QIO_CHANNEL(nbd_server->listen_ioc), 118 "nbd-listener"); 119 if (qio_channel_socket_listen_sync( 120 nbd_server->listen_ioc, addr, errp) < 0) { 121 goto error; 122 } 123 124 if (tls_creds) { 125 nbd_server->tlscreds = nbd_get_tls_creds(tls_creds, errp); 126 if (!nbd_server->tlscreds) { 127 goto error; 128 } 129 130 /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */ 131 if (addr->type != SOCKET_ADDRESS_TYPE_INET) { 132 error_setg(errp, "TLS is only supported with IPv4/IPv6"); 133 goto error; 134 } 135 } 136 137 nbd_server->watch = qio_channel_add_watch( 138 QIO_CHANNEL(nbd_server->listen_ioc), 139 G_IO_IN, 140 nbd_accept, 141 NULL, 142 NULL); 143 144 return; 145 146 error: 147 nbd_server_free(nbd_server); 148 nbd_server = NULL; 149 } 150 151 void qmp_nbd_server_start(SocketAddressLegacy *addr, 152 bool has_tls_creds, const char *tls_creds, 153 Error **errp) 154 { 155 SocketAddress *addr_flat = socket_address_flatten(addr); 156 157 nbd_server_start(addr_flat, tls_creds, errp); 158 qapi_free_SocketAddress(addr_flat); 159 } 160 161 void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, 162 Error **errp) 163 { 164 BlockDriverState *bs = NULL; 165 BlockBackend *on_eject_blk; 166 NBDExport *exp; 167 168 if (!nbd_server) { 169 error_setg(errp, "NBD server not running"); 170 return; 171 } 172 173 if (nbd_export_find(device)) { 174 error_setg(errp, "NBD server already exporting device '%s'", device); 175 return; 176 } 177 178 on_eject_blk = blk_by_name(device); 179 180 bs = bdrv_lookup_bs(device, device, errp); 181 if (!bs) { 182 return; 183 } 184 185 if (!has_writable) { 186 writable = false; 187 } 188 if (bdrv_is_read_only(bs)) { 189 writable = false; 190 } 191 192 exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, 193 NULL, false, on_eject_blk, errp); 194 if (!exp) { 195 return; 196 } 197 198 nbd_export_set_name(exp, device); 199 200 /* The list of named exports has a strong reference to this export now and 201 * our only way of accessing it is through nbd_export_find(), so we can drop 202 * the strong reference that is @exp. */ 203 nbd_export_put(exp); 204 } 205 206 void qmp_nbd_server_stop(Error **errp) 207 { 208 nbd_export_close_all(); 209 210 nbd_server_free(nbd_server); 211 nbd_server = NULL; 212 } 213