// SPDX-License-Identifier: GPL-2.0
/*
* This file is part of the Distributed Network Block Device 3
*
* Copyright(c) 2011-2012 Johann Latocha <johann@latocha.de>
*
* 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 <dnbd3/config/client.h>
#include <dnbd3/version.h>
#include <net/ipv6.h>
#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)");
