/*
* 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 "utils.h"
void dnbd3_net_connect(struct dnbd3_device *lo)
{
struct sockaddr_in sin;
struct msghdr msg;
struct kvec iov;
struct dnbd3_request dnbd3_request;
struct dnbd3_reply dnbd3_reply;
struct task_struct *thread_send;
struct task_struct *thread_receive;
if (!lo->host || !lo->port || !lo->image_id)
{
printk("ERROR: Host or port not set.");
return;
}
// initialize socket
if (sock_create_kern(AF_INET, SOCK_STREAM, IPPROTO_TCP, &lo->sock) < 0)
{
printk("ERROR: dnbd3 couldn't create socket.\n");
return;
}
lo->sock->sk->sk_allocation = GFP_NOIO;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = inet_addr(lo->host);
sin.sin_port = htons(simple_strtol(lo->port, NULL, 10));
if (kernel_connect(lo->sock, (struct sockaddr *) &sin, sizeof(sin), 0) < 0)
{
printk("ERROR: dnbd3 couldn't connect to given host.\n");
return;
}
// prepare message and send request
dnbd3_request.cmd = CMD_GET_SIZE;
strcpy(dnbd3_request.image_id, lo->image_id);
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
iov.iov_base = &dnbd3_request;
iov.iov_len = sizeof(dnbd3_request);
kernel_sendmsg(lo->sock, &msg, &iov, 1, sizeof(dnbd3_request));
// receive replay
iov.iov_base = &dnbd3_reply;
iov.iov_len = sizeof(dnbd3_reply);
kernel_recvmsg(lo->sock, &msg, &iov, 1, sizeof(dnbd3_reply), msg.msg_flags);
// set filesize
if (dnbd3_reply.filesize <= 0)
{
printk("ERROR: File size returned by server is < 0.\n");
return;
}
printk("INFO: dnbd3 filesize: %llu\n", dnbd3_reply.filesize);
set_capacity(lo->disk, dnbd3_reply.filesize >> 9); /* 512 Byte blocks */
// start sending thread
thread_send = kthread_create(dnbd3_net_send, lo, lo->disk->disk_name);
wake_up_process(thread_send);
// start receiving thread
thread_receive = kthread_create(dnbd3_net_receive, lo, lo->disk->disk_name);
wake_up_process(thread_receive);
}
int dnbd3_net_send(void *data)
{
struct dnbd3_device *lo = data;
struct dnbd3_request dnbd3_request;
struct request *blk_request;
struct msghdr msg;
struct kvec iov;
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
set_user_nice(current, -20);
while (!kthread_should_stop() || !list_empty(&lo->request_queue_send))
{
wait_event_interruptible(lo->process_queue_send,
kthread_should_stop() || !list_empty(&lo->request_queue_send));
if (list_empty(&lo->request_queue_send))
continue;
// extract block request
spin_lock_irq(&lo->blk_lock);
blk_request = list_entry(lo->request_queue_send.next, struct request, queuelist);
list_del_init(&blk_request->queuelist);
spin_unlock_irq(&lo->blk_lock);
// prepare net request
dnbd3_request.cmd = CMD_GET_BLOCK;
dnbd3_request.offset = blk_rq_pos(blk_request) << 9; // *512
dnbd3_request.size = blk_rq_bytes(blk_request); // blk_rq_bytes() Returns bytes left to complete in the entire request
memcpy(dnbd3_request.handle, &blk_request, sizeof(blk_request));
iov.iov_base = &dnbd3_request;
iov.iov_len = sizeof(dnbd3_request);
// send net request
if (kernel_sendmsg(lo->sock, &msg, &iov, 1, sizeof(dnbd3_request)) <= 0)
printk("ERROR: kernel_sendmsg\n");
spin_lock_irq(&lo->blk_lock);
list_add_tail(&blk_request->queuelist, &lo->request_queue_receive);
spin_unlock_irq(&lo->blk_lock);
wake_up(&lo->process_queue_receive);
}
return 0;
}
int dnbd3_net_receive(void *data)
{
struct dnbd3_device *lo = data;
struct dnbd3_reply dnbd3_reply;
struct request *blk_request;
struct msghdr msg;
struct kvec iov;
struct req_iterator iter;
struct bio_vec *bvec;
unsigned long flags;
sigset_t blocked, oldset;
struct request *tmp_request, *received_request;
void *kaddr;
unsigned int size;
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
set_user_nice(current, -20);
while (!kthread_should_stop() || !list_empty(&lo->request_queue_receive))
{
wait_event_interruptible(lo->process_queue_receive, kthread_should_stop() || !list_empty(&lo->request_queue_receive));
// receive net replay
iov.iov_base = &dnbd3_reply;
iov.iov_len = sizeof(dnbd3_reply);
kernel_recvmsg(lo->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(&lo->blk_lock);
list_for_each_entry_safe(blk_request, tmp_request, &lo->request_queue_receive, queuelist)
{
if (blk_request != received_request)
continue;
list_del_init(&blk_request->queuelist);
break;
}
spin_unlock_irq(&lo->blk_lock);
// 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(lo->sock, &msg, &iov, 1, size, msg.msg_flags);
kunmap(bvec->bv_page);
sigprocmask(SIG_SETMASK, &oldset, NULL);
}
spin_lock_irqsave(&lo->blk_lock, flags);
__blk_end_request_all(blk_request, 0);
spin_unlock_irqrestore(&lo->blk_lock, flags);
}
return 0;
}
