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#include <linux/fs.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <net/sock.h>
// Own
#include "config.h"
#include "include/types.h"
static int major;
static struct gendisk *disk;
static struct request_queue *dnbd3_queue;
DEFINE_SPINLOCK( dnbd3_lock);
static struct socket *_sock;
static struct dnbd3_request _dnbd3_request;
static struct dnbd3_reply _dnbd3_reply;
static char* host;
static char* port;
unsigned int inet_addr(char *str)
{
int a, b, c, d;
char arr[4];
sscanf(str, "%d.%d.%d.%d", &a, &b, &c, &d);
arr[0] = a;
arr[1] = b;
arr[2] = c;
arr[3] = d;
return *(unsigned int*) arr;
}
void connect(void)
{
if (!host || !port)
{
printk("ERROR: Host or port not set.");
return;
}
// initialize socket
struct sockaddr_in sin;
if (sock_create_kern(AF_INET, SOCK_STREAM, IPPROTO_TCP, &_sock) < 0)
{
printk("ERROR: dnbd3 couldn't create socket.\n");
return;
}
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = inet_addr(host);
sin.sin_port = htons(simple_strtol(port, NULL, 10));
if (kernel_connect(_sock, (struct sockaddr *) &sin, sizeof(sin), 0) < 0)
{
printk("ERROR: dnbd3 couldn't connect to given host.\n");
return;
}
// prepare message
struct msghdr msg;
struct kvec iov;
_sock->sk->sk_allocation = GFP_NOIO; // GFP_NOIO: blocking is possible, but no I/O will be performed.
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = MSG_WAITALL | MSG_NOSIGNAL; // No SIGPIPE
// send request
_dnbd3_request.cmd = CMD_GET_SIZE;
iov.iov_base = &_dnbd3_request;
iov.iov_len = sizeof(_dnbd3_request);
kernel_sendmsg(_sock, &msg, &iov, 1, sizeof(_dnbd3_request));
// receive replay
iov.iov_base = &_dnbd3_reply;
iov.iov_len = sizeof(_dnbd3_reply);
kernel_recvmsg(_sock, &msg, &iov, 1, sizeof(_dnbd3_reply), msg.msg_flags);
// set filesize
printk("INFO: dnbd3 filesize: %llu\n", _dnbd3_reply.filesize);
set_capacity(disk, _dnbd3_reply.filesize >> 9); /* 512 Byte blocks */
}
void dnbd3_request(struct request_queue *q)
{
if (!_sock)
return;
struct request *req;
struct msghdr msg;
struct kvec iov;
_sock->sk->sk_allocation = GFP_NOIO; // GFP_NOIO: blocking is possible, but no I/O will be performed.
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = MSG_WAITALL | MSG_NOSIGNAL; // No SIGPIPE
while ((req = blk_fetch_request(q)) != NULL)
{
if (req->cmd_type != REQ_TYPE_FS)
{
if (!__blk_end_request_cur(req, 0))
req = blk_fetch_request(q);
continue;
}
spin_unlock_irq(q->queue_lock);
if (rq_data_dir(req) == READ)
{
_dnbd3_request.cmd = CMD_GET_BLOCK;
_dnbd3_request.offset = blk_rq_pos(req) << 9; // *512
_dnbd3_request.size = blk_rq_bytes(req); // blk_rq_bytes() Returns bytes left to complete in the entire request
// send request
iov.iov_base = &_dnbd3_request;
iov.iov_len = sizeof(_dnbd3_request);
kernel_sendmsg(_sock, &msg, &iov, 1, sizeof(_dnbd3_request));
// receive replay
struct req_iterator iter;
struct bio_vec *bvec;
rq_for_each_segment(bvec, req, iter)
{
iov.iov_base = kmap(bvec->bv_page) + bvec->bv_offset;
iov.iov_len = bvec->bv_len;
kernel_recvmsg(_sock, &msg, &iov, 1, bvec->bv_len, msg.msg_flags);
kunmap(bvec->bv_page);
}
}
spin_lock_irq(q->queue_lock);
__blk_end_request_all(req, 0);
}
}
int dnbd3_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
switch (cmd)
{
case IOCTL_SET_HOST:
host = (char *) arg;
break;
case IOCTL_SET_PORT:
port = (char *) arg;
break;
case IOCTL_CONNECT:
connect();
break;
case BLKFLSBUF:
// TODO: if missing, hdparm tells "BLKFLSBUF failed: Operation not permitted". Figure out what this should do.
break;
default:
return -1;
}
return 0;
}
struct block_device_operations dnbd3_ops =
{ .owner = THIS_MODULE, .ioctl = dnbd3_ioctl, };
static int __init dnbd3_init(void)
{
// Init blkdev
if ((major = register_blkdev(0, "dnbd")) == 0)
{
printk("ERROR: dnbd3 register_blkdev failed.\n");
return -EIO;
}
if (!(disk = alloc_disk(1)))
{
printk("ERROR: dnbd3 alloc_disk failed.\n");
return -EIO;
}
disk->major = major;
disk->first_minor = 0;
sprintf(disk->disk_name, "dnbd0");
set_capacity(disk, 0);
//set_disk_ro(disk, 1);
disk->fops = &dnbd3_ops;
if ((dnbd3_queue = blk_init_queue(&dnbd3_request, &dnbd3_lock)) == NULL)
{
printk("ERROR: dnbd3 blk_init_queue failed.\n");
return -EIO;
}
blk_queue_logical_block_size(dnbd3_queue, DNBD3_BLOCK_SIZE); // set logical block size for the queue
disk->queue = dnbd3_queue;
add_disk(disk);
printk("INFO: dnbd3 init successful.\n");
return 0;
}
static void __exit dnbd3_exit(void)
{
if (_sock)
sock_release(_sock);
unregister_blkdev(major, "dnbd");
del_gendisk(disk);
put_disk(disk);
blk_cleanup_queue(dnbd3_queue);
printk("INFO: dnbd3 exit.\n");
}
module_init( dnbd3_init);
module_exit( dnbd3_exit);
MODULE_LICENSE("GPL");
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