/*
* 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 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.
*
*/
#include "net.h"
#include "blk.h"
#include "utils.h"
void dnbd3_net_connect(dnbd3_device_t *dev)
{
struct sockaddr_in sin;
struct request *req = kmalloc(sizeof(struct request), GFP_ATOMIC);
// do some checks before connecting
if (!req)
{
printk("ERROR: Kmalloc failed.\n");
return;
}
if (!dev->host || !dev->port || (dev->vid == 0))
{
printk("ERROR: Host, port or vid not set.\n");
return;
}
if (dev->sock)
{
printk("ERROR: Device %s already connected to %s.\n", dev->disk->disk_name, dev->host);
return;
}
printk("INFO: Connecting device %s to %s\n", dev->disk->disk_name, dev->host);
// initialize socket
if (sock_create_kern(AF_INET, SOCK_STREAM, IPPROTO_TCP, &dev->sock) < 0)
{
printk("ERROR: Couldn't create socket.\n");
dev->sock = NULL;
return;
}
dev->sock->sk->sk_allocation = GFP_NOIO;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = inet_addr(dev->host);
sin.sin_port = htons(simple_strtol(dev->port, NULL, 10));
if (kernel_connect(dev->sock, (struct sockaddr *) &sin, sizeof(sin), 0) < 0)
{
printk("ERROR: Couldn't connect to host %s:%s\n", dev->host, dev->port);
dev->sock = NULL;
return;
}
// start sending thread
dev->thread_send = kthread_create(dnbd3_net_send, dev, dev->disk->disk_name);
wake_up_process(dev->thread_send);
// start receiving thread
dev->thread_receive = kthread_create(dnbd3_net_receive, dev, dev->disk->disk_name);
wake_up_process(dev->thread_receive);
// add heartbeat timer
init_timer(&dev->hb_timer);
dev->hb_timer.data = (unsigned long) dev;
dev->hb_timer.function = dnbd3_net_heartbeat;
dev->hb_timer.expires = jiffies + HB_INTERVAL;
add_timer(&dev->hb_timer);
// enqueue request to request_queue_send (ask file size)
req->cmd_type = REQ_TYPE_SPECIAL;
req->cmd_flags = REQ_GET_FILESIZE;
list_add(&req->queuelist, &dev->request_queue_send);
wake_up(&dev->process_queue_send);
}
void dnbd3_net_disconnect(dnbd3_device_t *dev)
{
struct request *blk_request, *tmp_request;
printk("INFO: Disconnecting device %s\n", dev->disk->disk_name);
// kill sending and receiving threads
if (dev->thread_send && dev->thread_receive)
{
kthread_stop(dev->thread_send);
kthread_stop(dev->thread_receive);
}
// clear socket
if (dev->sock)
{
sock_release(dev->sock);
dev->sock = NULL;
}
// clear heartbeat timer
if (&dev->hb_timer)
del_timer(&dev->hb_timer);
// move already send requests to request_queue_send again
if (!list_empty(&dev->request_queue_receive))
{
printk("WARN: Request queue was not empty on %s\n", dev->disk->disk_name);
spin_lock_irq(&dev->blk_lock);
list_for_each_entry_safe(blk_request, tmp_request, &dev->request_queue_receive, queuelist)
{
list_del_init(&blk_request->queuelist);
list_add_tail(&blk_request->queuelist, &dev->request_queue_send);
}
spin_unlock_irq(&dev->blk_lock);
}
}
int dnbd3_net_send(void *data)
{
dnbd3_device_t *dev = data;
struct request *blk_request;
dnbd3_request_t dnbd3_request;
struct msghdr msg;
struct kvec iov;
init_msghdr(msg);
set_user_nice(current, -20);
while (!kthread_should_stop() || !list_empty(&dev->request_queue_send))
{
wait_event_interruptible(dev->process_queue_send,
kthread_should_stop() || !list_empty(&dev->request_queue_send));
if (list_empty(&dev->request_queue_send))
continue;
// extract block request
spin_lock_irq(&dev->blk_lock);
blk_request = list_entry(dev->request_queue_send.next, struct request, queuelist);
list_del_init(&blk_request->queuelist);
spin_unlock_irq(&dev->blk_lock);
// what to do?
switch (blk_request->cmd_type)
{
case REQ_TYPE_FS:
dnbd3_request.cmd = CMD_GET_BLOCK;
dnbd3_request.offset = blk_rq_pos(blk_request) << 9; // *512
dnbd3_request.size = blk_rq_bytes(blk_request); // bytes left to complete entire request
break;
case REQ_TYPE_SPECIAL:
switch (blk_request->cmd_flags)
{
case REQ_GET_FILESIZE:
dnbd3_request.cmd = CMD_GET_SIZE;
dnbd3_request.vid = dev->vid;
dnbd3_request.rid = dev->rid;
break;
case REQ_GET_SERVERS:
dnbd3_request.cmd = CMD_GET_SERVERS;
break;
}
break;
default:
printk("ERROR: Unknown command (Send)\n");
continue;
}
// send net request
memcpy(dnbd3_request.handle, &blk_request, sizeof(blk_request));
iov.iov_base = &dnbd3_request;
iov.iov_len = sizeof(dnbd3_request);
if (kernel_sendmsg(dev->sock, &msg, &iov, 1, sizeof(dnbd3_request)) <= 0)
printk("ERROR: kernel_sendmsg\n");
// enqueue request to request_queue_receive
spin_lock_irq(&dev->blk_lock);
list_add_tail(&blk_request->queuelist, &dev->request_queue_receive);
spin_unlock_irq(&dev->blk_lock);
wake_up(&dev->process_queue_receive);
}
return 0;
}
int dnbd3_net_receive(void *data)
{
dnbd3_device_t *dev = data;
struct request *blk_request, *tmp_request, *received_request;
dnbd3_reply_t dnbd3_reply;
struct msghdr msg;
struct kvec iov;
struct req_iterator iter;
struct bio_vec *bvec;
void *kaddr;
unsigned long flags;
sigset_t blocked, oldset;
unsigned int size, i;
uint64_t filesize;
init_msghdr(msg);
set_user_nice(current, -20);
while (!kthread_should_stop() || !list_empty(&dev->request_queue_receive))
{
wait_event_interruptible(dev->process_queue_receive,
kthread_should_stop() || !list_empty(&dev->request_queue_receive));
if (list_empty(&dev->request_queue_receive))
continue;
// receive net replay
iov.iov_base = &dnbd3_reply;
iov.iov_len = sizeof(dnbd3_reply);
kernel_recvmsg(dev->sock, &msg, &iov, 1, sizeof(dnbd3_reply), msg.msg_flags);
// search for replied request in queue
received_request = *(struct request **) dnbd3_reply.handle;
spin_lock_irq(&dev->blk_lock);
list_for_each_entry_safe(blk_request, tmp_request, &dev->request_queue_receive, queuelist)
{
if (blk_request != received_request)
continue;
list_del_init(&blk_request->queuelist);
break;
}
spin_unlock_irq(&dev->blk_lock);
// check if server send error
switch (dnbd3_reply.error)
{
case ERROR_SIZE:
printk("ERROR: Requested image does't exist\n");
kthread_stop(dev->thread_send);
del_timer(&dev->hb_timer);
sock_release(dev->sock);
kfree(blk_request);
dev->sock = NULL;
return -1;
case ERROR_RELOAD:
blk_request->cmd_type = REQ_TYPE_SPECIAL;
blk_request->cmd_flags = REQ_GET_FILESIZE;
list_add(&blk_request->queuelist, &dev->request_queue_send);
wake_up(&dev->process_queue_send);
continue;
}
// what to do?
switch (dnbd3_reply.cmd)
{
case CMD_GET_BLOCK:
// receive data and answer to block layer
rq_for_each_segment(bvec, blk_request, iter)
{
siginitsetinv(&blocked, sigmask(SIGKILL));
sigprocmask(SIG_SETMASK, &blocked, &oldset);
kaddr = kmap(bvec->bv_page) + bvec->bv_offset;
size = bvec->bv_len;
iov.iov_base = kaddr;
iov.iov_len = size;
kernel_recvmsg(dev->sock, &msg, &iov, 1, size, msg.msg_flags);
kunmap(bvec->bv_page);
sigprocmask(SIG_SETMASK, &oldset, NULL);
}
spin_lock_irqsave(&dev->blk_lock, flags);
__blk_end_request_all(blk_request, 0);
spin_unlock_irqrestore(&dev->blk_lock, flags);
continue;
case CMD_GET_SIZE:
iov.iov_base = &filesize;
iov.iov_len = sizeof(uint64_t);
kernel_recvmsg(dev->sock, &msg, &iov, 1, dnbd3_reply.size, msg.msg_flags);
set_capacity(dev->disk, filesize >> 9); /* 512 Byte blocks */
printk("INFO: Filesize %s: %llu\n", dev->disk->disk_name, filesize);
kfree(blk_request);
continue;
case CMD_GET_SERVERS:
dev->num_servers = dnbd3_reply.size / sizeof(struct in_addr);
size = sizeof(struct in_addr);
for (i = 0; i < dev->num_servers && i < MAX_NUMBER_SERVERS; i++)
{
iov.iov_base = &dev->servers[i];
iov.iov_len = size;
kernel_recvmsg(dev->sock, &msg, &iov, 1, size, msg.msg_flags);
}
kfree(blk_request);
continue;
default:
printk("ERROR: Unknown command (Receive)\n");
continue;
}
}
return 0;
}
void dnbd3_net_heartbeat(unsigned long arg)
{
dnbd3_device_t *dev = (dnbd3_device_t *) arg;
struct request *req = kmalloc(sizeof(struct request), GFP_ATOMIC);
if (req)
{
req->cmd_type = REQ_TYPE_SPECIAL;
req->cmd_flags = REQ_GET_SERVERS;
list_add(&req->queuelist, &dev->request_queue_send);
wake_up(&dev->process_queue_send);
}
dev->hb_timer.expires = jiffies + HB_INTERVAL;
add_timer(&dev->hb_timer);
}
