// SPDX-License-Identifier: GPL-2.0 /* * This file is part of the Distributed Network Block Device 3 * * Copyright(c) 2011-2012 Johann Latocha * * This file may be licensed under the terms of the * GNU General Public License Version 2 (the ``GPL''). * * Software distributed under the License is distributed * on an ``AS IS'' basis, WITHOUT WARRANTY OF ANY KIND, either * express or implied. See the GPL for the specific language * governing rights and limitations. * * You should have received a copy of the GPL along with this * program. If not, go to http://www.gnu.org/licenses/gpl.html * or write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include "dnbd3_main.h" #include "blk.h" int major; static unsigned int max_devs = NUMBER_DEVICES; static dnbd3_device_t *dnbd3_devices; struct device *dnbd3_device_to_dev(dnbd3_device_t *dev) { return disk_to_dev(dev->disk); } int dnbd3_host_to_sockaddr(const dnbd3_host_t *host, struct sockaddr_storage *dest) { struct sockaddr_in *sin4; struct sockaddr_in6 *sin6; memset(dest, 0, sizeof(*dest)); if (host->type == HOST_IP4) { sin4 = (struct sockaddr_in *)dest; sin4->sin_family = AF_INET; memcpy(&(sin4->sin_addr), host->addr, 4); sin4->sin_port = host->port; } else if (host->type == HOST_IP6) { sin6 = (struct sockaddr_in6 *)dest; sin6->sin6_family = AF_INET6; memcpy(&(sin6->sin6_addr), host->addr, 16); sin6->sin6_port = host->port; } else return 0; return 1; } int is_same_server(const struct sockaddr_storage *const x, const struct sockaddr_storage *const y) { if (x->ss_family != y->ss_family) return 0; switch (x->ss_family) { case AF_INET: { const struct sockaddr_in *sinx = (const struct sockaddr_in *)x; const struct sockaddr_in *siny = (const struct sockaddr_in *)y; if (sinx->sin_port != siny->sin_port) return 0; if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr) return 0; break; } case AF_INET6: { const struct sockaddr_in6 *sinx = (const struct sockaddr_in6 *)x; const struct sockaddr_in6 *siny = (const struct sockaddr_in6 *)y; if (sinx->sin6_port != siny->sin6_port) return 0; if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr)) return 0; break; } default: return 0; } return 1; } /** * Get a free slot pointer from the alt_servers list. Tries to find an * entirely empty slot first, then looks for a slot with a server that * wasn't reachable recently, finally returns NULL if none of the * conditions match. * The caller has to hold dev->alt_servers_lock. */ static dnbd3_alt_server_t *get_free_alt_server(dnbd3_device_t *const dev) { int i; for (i = 0; i < NUMBER_SERVERS; ++i) { if (dev->alt_servers[i].host.ss_family == 0) return &dev->alt_servers[i]; } for (i = 0; i < NUMBER_SERVERS; ++i) { if (dev->alt_servers[i].failures > 10) return &dev->alt_servers[i]; } return NULL; } dnbd3_alt_server_t *get_existing_alt_from_addr(const struct sockaddr_storage *const addr, dnbd3_device_t *const dev) { int i; for (i = 0; i < NUMBER_SERVERS; ++i) { if (is_same_server(addr, &dev->alt_servers[i].host)) return &dev->alt_servers[i]; } return NULL; } /** * Returns pointer to existing entry in alt_servers that matches the given * alt server, or NULL if not found. * The caller has to hold dev->alt_servers_lock. */ dnbd3_alt_server_t *get_existing_alt_from_host(const dnbd3_host_t *const host, dnbd3_device_t *const dev) { struct sockaddr_storage addr; if (!dnbd3_host_to_sockaddr(host, &addr)) return NULL; return get_existing_alt_from_addr(&addr, dev); } int dnbd3_add_server(dnbd3_device_t *dev, dnbd3_host_t *host) { int result; dnbd3_alt_server_t *alt_server; if (host->type != HOST_IP4 && host->type != HOST_IP6) return -EINVAL; /* protect access to 'alt_servers' */ mutex_lock(&dev->alt_servers_lock); alt_server = get_existing_alt_from_host(host, dev); // ADD if (alt_server != NULL) { // Exists result = -EEXIST; } else { // OK add alt_server = get_free_alt_server(dev); if (alt_server == NULL) { result = -ENOSPC; } else { dnbd3_host_to_sockaddr(host, &alt_server->host); alt_server->protocol_version = 0; alt_server->rtts[0] = alt_server->rtts[1] = alt_server->rtts[2] = alt_server->rtts[3] = RTT_UNREACHABLE; alt_server->failures = 0; alt_server->best_count = 0; result = 0; } } mutex_unlock(&dev->alt_servers_lock); return result; } int dnbd3_rem_server(dnbd3_device_t *dev, dnbd3_host_t *host) { dnbd3_alt_server_t *alt_server; int result; /* protect access to 'alt_servers' */ mutex_lock(&dev->alt_servers_lock); alt_server = get_existing_alt_from_host(host, dev); // REMOVE if (alt_server == NULL) { // Not found result = -ENOENT; } else { // Remove alt_server->host.ss_family = 0; result = 0; } mutex_unlock(&dev->alt_servers_lock); return result; } static int __init dnbd3_init(void) { int i; dnbd3_devices = kcalloc(max_devs, sizeof(*dnbd3_devices), GFP_KERNEL); if (!dnbd3_devices) return -ENOMEM; // initialize block device major = register_blkdev(0, "dnbd3"); if (major == 0) { pr_err("register_blkdev failed\n"); return -EIO; } pr_info("kernel module in version %s loaded\n", DNBD3_VERSION); pr_debug("machine type %s\n", DNBD3_ENDIAN_MODE); // add MAX_NUMBER_DEVICES devices for (i = 0; i < max_devs; i++) { if (dnbd3_blk_add_device(&dnbd3_devices[i], i) != 0) { pr_err("dnbd3_blk_add_device failed\n"); // TODO: delete all devices added so far. // It could happen that it's not the first one that fails. // Also call unregister_blkdev and free memory. return -EIO; } } pr_info("init successful (%i devices)\n", max_devs); return 0; } static void __exit dnbd3_exit(void) { int i; pr_debug("exiting kernel module...\n"); for (i = 0; i < max_devs; i++) dnbd3_blk_del_device(&dnbd3_devices[i]); unregister_blkdev(major, "dnbd3"); kfree(dnbd3_devices); pr_info("exit kernel module done\n"); } module_init(dnbd3_init); module_exit(dnbd3_exit); MODULE_DESCRIPTION("Distributed Network Block Device 3"); MODULE_LICENSE("GPL"); MODULE_VERSION(DNBD3_VERSION); module_param(max_devs, int, 0444); MODULE_PARM_DESC(max_devs, "number of network block devices to initialize (default: 8)");