path: root/src/kernel/dnbd3.h

/*
 * This file is part of the Distributed Network Block Device 3
 *
 * Copyright(c) 2019 Frederic Robra <frederic@robra.org>
 * Parts copyright 2011-2012 Johann Latocha <johann@latocha.de>
 *
 * This file may be licensed under the terms of 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.
 *
 */
#ifndef DNBD_H_
#define DNBD_H_

#include <linux/blk-mq.h>
#include <linux/types.h>
#include <linux/refcount.h>
#include <linux/blkdev.h>

#define KERNEL_MODULE
#include "types.h"
#include "serialize.h"

/**
 * the number of parallel connections
 */
#define NUMBER_CONNECTIONS 4 // power of 2

/**
 * limit to which the other connected servers are only allowed to be that worser then the best rtt
 */
#define RTT_THRESOULD_LIMIT(best_rtt) ((best_rtt) * 10)

#define DEBUG


extern struct workqueue_struct *dnbd3_wq;

/**
 * struct dnbd3_server - defining a server for dnbd3
 * @host: host of this server
 * @rtts: last four round trip time measurements in microseconds
 * @protocol_version: dnbd3 protocol version of this server
 * @failures: how many times the server was unreachable
 */
struct dnbd3_server {
	dnbd3_host_t host;
	uint64_t rtts[4];
	uint16_t protocol_version;
	uint8_t failures;
};

/**
 * struct dnbd3_sock - defining a socket for dnbd3
 * @sock_nr: nr of this socket
 * @device: the dnbd3_device this socket belongs to
 * @server: the server this socket is connected to, 'NULL' if not connected
 * @tx_lock: mutex to lock when sending
 * @sock: the socket, 'NULL' if not connected
 * @panic: 'true' if it is not possible to send or receive
 * @cookie: is incremented for every send, used to find the mq request in the receiver
 * @keepalive_worker: worker to send a keepalive package
 * @receive_worker: worker to handle the incoming packages
 * @pending: the pending request which is going to be send
 * @receive_command: the last command the receiver got
 */
struct dnbd3_sock {
	uint8_t sock_nr;
	struct dnbd3_device *device;
	struct dnbd3_server *server;

	struct mutex tx_lock;
	struct socket *sock;

	bool panic;
	uint32_t cookie;

	struct work_struct keepalive_worker;
	struct work_struct receive_worker;

	struct request *pending;
	uint16_t receive_command;
};

/**
 * struct dnbd3_device - defining a dnbd3 device
 * @minor: minor number of this device
 * @tag_set: the blk mq tag set
 * @list: list of previous and next dnbd3_device
 * @disk: the gendisk
 * @kobj: the kobject
 * @device_lock: mutex to lock when device changes
 * @socks: array of dnbd3_sock to connect to
 * @imgname: the connected image name
 * @initial_server: the server which was configured with ioctl, will not be overriden
 * @alt_servers: array of alternative servers
 * @new_servers_num: number of new alternative servers that are waiting to be copied to above array
 * @new_servers: pending new alternative servers
 * @update_available: 'true' if the rid has changes
 * @use_server_provided_alts: 'true' if the alt_servers array is upated by the alternatives provided by the server
 * @rid: the revision ID? TODO
 * @reported_size: the size of the image
 * @panic_worker: worker to handle panics and to connect if all connections are down
 * @discovery_worker: worker to update the alt_servers, make rtt meassurement and reconnect to better servers
 * @discovery_count: counter for the discovery worker
 * @timer: timer to start the appropriate workers
 * @timer_count: counter for the timer
 */
struct dnbd3_device {
	int minor;
	struct blk_mq_tag_set tag_set;
	struct list_head list;

	// block
	struct gendisk *disk;

	// sysfs
	struct kobject kobj;

	struct mutex device_lock;

	// network
	struct dnbd3_sock socks[NUMBER_CONNECTIONS];
	char *imgname;
	struct dnbd3_server initial_server;
	struct dnbd3_server alt_servers[NUMBER_SERVERS]; // array of alt servers
	int new_servers_num;	// number of new alt servers that are waiting to be copied to above array
	dnbd3_server_entry_t new_servers[NUMBER_SERVERS]; // pending new alt servers
	bool update_available;
	bool use_server_provided_alts;
	uint16_t rid;
	uint64_t reported_size;

	struct work_struct panic_worker;
	struct work_struct discovery_worker;
	uint8_t discovery_count;
	struct timer_list timer;
	uint8_t timer_count;
};


/**
 * struct dnbd3_cmd - defines a mq cmd for dnbd3
 * @dnbd3: the dnbd3 device this command belongs to
 * @lock: mutex to lock the cmd
 * @cookie: the cookie of the command, this is set by the socket when sending
 * @status: the status of the command
 * @requed: 'true' if the command is requed
 */
struct dnbd3_cmd {
	struct dnbd3_device *dnbd3;
	struct mutex lock;
	uint32_t cookie;
	blk_status_t status;
	bool requed;
};


#define __print_sock(level, sock, fmt, ...) \
	do { \
		if ((sock)->server->host.type == HOST_IP4) { \
			printk(level "dnbd%d/%d %pI4:%d: " fmt "\n", (sock)->device->minor, (sock)->sock_nr, (sock)->server->host.addr, (sock)->server->host.port, ## __VA_ARGS__); \
		} else { \
			printk(level "dnbd%d/%d %pI6:%d: " fmt "\n", (sock)->device->minor, (sock)->sock_nr, (sock)->server->host.addr, (sock)->server->host.port, ## __VA_ARGS__); \
		} \
	} while (0)

#define __print_server(level, dev, server, fmt, ...) \
	do { \
		if ((server)->host.type == HOST_IP4) { \
			printk(level "dnbd%d: " fmt " %pI4:%d\n", (dev)->minor, ## __VA_ARGS__, (server)->host.addr, (server)->host.port); \
		} else { \
			printk(level "dnbd%d: " fmt " %pI6:%d\n", (dev)->minor, ## __VA_ARGS__, (server)->host.addr, (server)->host.port); \
		} \
	} while (0)


#ifdef DEBUG

#define debug(fmt, ...) \
	printk(KERN_DEBUG "dnbd: " fmt "\n", ## __VA_ARGS__)

#define debug_dev(dev, fmt, ...) \
	printk(KERN_DEBUG "dnbd%d: " fmt "\n", (dev)->minor, ## __VA_ARGS__)

#define debug_sock(sock, fmt, ...) \
	__print_sock(KERN_DEBUG, sock, fmt, ## __VA_ARGS__)

#define debug_server(dev, server, fmt, ...) \
	__print_server(KERN_DEBUG, dev, server, fmt, ## __VA_ARGS__)

#else

#define debug(fmt, ...)

#define debug_dev(dev, fmt, ...)

#define debug_sock(sock, fmt, ...)

#define debug_server(dev, server, fmt, ...)

#endif

#define info(fmt, ...) \
	printk(KERN_INFO "dnbd: " fmt "\n", ## __VA_ARGS__)

#define info_dev(dev, fmt, ...) \
	printk(KERN_INFO "dnbd%d: " fmt "\n", (dev)->minor, ## __VA_ARGS__)

#define info_sock(sock, fmt, ...) \
	__print_sock(KERN_INFO, sock, fmt, ## __VA_ARGS__)

#define info_server(dev, server, fmt, ...) \
	__print_server(KERN_INFO, dev, server, fmt, ## __VA_ARGS__)


#define warn(fmt, ...) \
	printk(KERN_WARNING "dnbd: " fmt "\n", ## __VA_ARGS__)

#define warn_dev(dev, fmt, ...) \
	printk(KERN_WARNING "dnbd%d: " fmt "\n", (dev)->minor, ## __VA_ARGS__)

#define warn_sock(sock, fmt, ...) \
	__print_sock(KERN_WARNING, sock, fmt, ## __VA_ARGS__)

#define warn_server(dev, server, fmt, ...) \
	__print_server(KERN_WARNING, dev, server, fmt, ## __VA_ARGS__)


#define error(fmt, ...) \
	printk(KERN_ERR "dnbd: " fmt "\n", ## __VA_ARGS__)

#define error_dev(dev, fmt, ...) \
	printk(KERN_ERR "dnbd%d: " fmt "\n", (dev)->minor, ## __VA_ARGS__)

#define error_sock(sock, fmt, ...) \
	__print_sock(KERN_ERR, sock, fmt, ## __VA_ARGS__)

#define error_server(dev, server, fmt, ...) \
	__print_server(KERN_ERR, dev, server, fmt, ## __VA_ARGS__)

#endif /* DNBD_H_ */