added first draft for keepalive and discovery

12 files changed, 888 insertions, 718 deletions

diff --git a/Kbuild.in b/Kbuild.in
index 566a58b..68c1d02 100644
--- a/Kbuild.in
+++ b/Kbuild.in
@@ -1,2 +1,2 @@
 obj-m := ${MODULE_NAME}.o
-${MODULE_NAME}-objs += core.o sysfs.o block.o mq.o utils.o serialize_kmod.o
+${MODULE_NAME}-objs += core.o sysfs.o net.o utils.o serialize_kmod.o
diff --git a/src/kernel/block.c b/src/kernel/block.c
deleted file mode 100644
index 4295418..0000000
--- a/src/kernel/block.c
+++ /dev/null
@@ -1,399 +0,0 @@
-/*
- * block.c
- *
- *  Created on: Jun 26, 2019
- *      Author: fred
- */
-
-#include <net/sock.h>
-
-#include "dnbd3.h"
-#include "block.h"
-#include "clientconfig.h"
-
-#define dnbd3_sock_create(af,type,proto,sock) sock_create_kern(&init_net, (af) == HOST_IP4 ? AF_INET : AF_INET6, type, proto, sock)
-
-
-
-
-void dnbd3_blk_fail_all_requests(dnbd3_device_t *dev)
-{
-	printk(KERN_DEBUG "dnbd3: fail all requests device %i\n", dev->minor);
-}
-
-
-int dnbd3_socket_connect(dnbd3_device_t *dev, dnbd3_sock *sock)
-{
-	int result = -EIO;
-	struct request *req1 = NULL;
-	struct timeval timeout;
-	struct dnbd3_server_t *server = sock->server;
-	dnbd3_request_t dnbd3_request;
-	dnbd3_reply_t dnbd3_reply;
-	struct msghdr msg;
-	struct kvec iov[2];
-	uint16_t rid;
-	uint64_t reported_size;
-	char *name;
-	int mlen;
-	serialized_buffer_t payload_buffer;
-
-	printk(KERN_DEBUG "dnbd3: socket connect device %i\n", dev->minor);
-
-	mutex_init(&sock->lock);
-	mutex_lock(&sock->lock);
-	if (sock->pending) {
-		printk(KERN_DEBUG "dnbd3: socket still in request\n");
-		while (sock->pending)
-			schedule();
-	}
-	if (server->host.port == 0 || server->host.type == 0) {
-		printk(KERN_ERR "dnbd3: host or port not set\n");
-		goto error;
-	}
-	if (sock->sock) {
-		printk(KERN_WARNING "dnbd3: socket already connected\n");
-		goto error;
-	}
-
-	timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DATA;
-	timeout.tv_usec = 0;
-
-	req1 = kmalloc(sizeof(*req1), GFP_ATOMIC );
-	if (!req1) {
-		printk(KERN_ERR "dnbd3: kmalloc failed\n");
-		goto error;
-	}
-
-	init_msghdr(msg);
-
-	if (dnbd3_sock_create(server->host.type, SOCK_STREAM, IPPROTO_TCP, &sock->sock) < 0) {
-		printk(KERN_ERR "dnbd3: could not create socket\n");
-		goto error;
-	}
-
-	kernel_setsockopt(sock->sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
-	kernel_setsockopt(sock->sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
-	sock->sock->sk->sk_allocation = GFP_NOIO;
-	if (server->host.type == HOST_IP4) {
-		struct sockaddr_in sin;
-		memset(&sin, 0, sizeof(sin));
-		sin.sin_family = AF_INET;
-		memcpy(&(sin.sin_addr), server->host.addr, 4);
-		sin.sin_port = server->host.port;
-		if (kernel_connect(sock->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0) {
-			printk(KERN_ERR "dnbd3: connection to host failed (ipv4)\n");
-			goto error;
-		}
-	} else {
-		struct sockaddr_in6 sin;
-		memset(&sin, 0, sizeof(sin));
-		sin.sin6_family = AF_INET6;
-		memcpy(&(sin.sin6_addr), server->host.addr, 16);
-		sin.sin6_port = server->host.port;
-		if (kernel_connect(sock->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0){
-			printk(KERN_ERR "dnbd3: connection to host failed (ipv6)\n");
-			goto error;
-		}
-	}
-	// Request filesize
-	dnbd3_request.magic = dnbd3_packet_magic;
-	dnbd3_request.cmd = CMD_SELECT_IMAGE;
-	iov[0].iov_base = &dnbd3_request;
-	iov[0].iov_len = sizeof(dnbd3_request);
-	serializer_reset_write(&payload_buffer);
-	serializer_put_uint16(&payload_buffer, PROTOCOL_VERSION);
-	serializer_put_string(&payload_buffer, dev->imgname);
-	serializer_put_uint16(&payload_buffer, dev->rid);
-	serializer_put_uint8(&payload_buffer, 0); // is_server = false
-	iov[1].iov_base = &payload_buffer;
-	dnbd3_request.size = iov[1].iov_len = serializer_get_written_length(&payload_buffer);
-	fixup_request(dnbd3_request);
-	mlen = sizeof(dnbd3_request) + iov[1].iov_len;
-	if (kernel_sendmsg(sock->sock, &msg, iov, 2, mlen) != mlen) {
-		printk(KERN_ERR "dnbd3: could not send CMD_SIZE_REQUEST\n");
-		goto error;
-	}
-	// receive reply header
-	iov[0].iov_base = &dnbd3_reply;
-	iov[0].iov_len = sizeof(dnbd3_reply);
-	if (kernel_recvmsg(sock->sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply)) {
-		printk(KERN_ERR "dnbd3: received corrupted reply header after CMD_SIZE_REQUEST\n");
-		goto error;
-	}
-
-	// check reply header
-	fixup_reply(dnbd3_reply);
-	if (dnbd3_reply.cmd != CMD_SELECT_IMAGE ||
-			dnbd3_reply.size < 3 ||
-			dnbd3_reply.size > MAX_PAYLOAD ||
-			dnbd3_reply.magic != dnbd3_packet_magic) {
-		printk(KERN_ERR "dnbd3: received invalid reply to CMD_SIZE_REQUEST image does not exist on server\n");
-		goto error;
-	}
-
-	// receive reply payload
-	iov[0].iov_base = &payload_buffer;
-	iov[0].iov_len = dnbd3_reply.size;
-	if (kernel_recvmsg(sock->sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != dnbd3_reply.size) {
-		printk(KERN_ERR "dnbd3: could not read CMD_SELECT_IMAGE payload on handshake\n");
-		goto error;
-	}
-
-	// handle/check reply payload
-	serializer_reset_read(&payload_buffer, dnbd3_reply.size);
-	server->protocol_version = serializer_get_uint16(&payload_buffer);
-	if (server->protocol_version < MIN_SUPPORTED_SERVER) {
-		printk(KERN_ERR "dnbd3: server version is lower than min supported version\n");
-		goto error;
-	}
-
-	name = serializer_get_string(&payload_buffer);
-	rid = serializer_get_uint16(&payload_buffer);
-	if (dev->rid != rid && strcmp(name, dev->imgname) != 0) {
-		printk(KERN_ERR "dnbd3: server offers image '%s', requested '%s'\n", name, dev->imgname);
-		goto error;
-	}
-
-	reported_size = serializer_get_uint64(&payload_buffer);
-	if (dev->reported_size == NULL) {
-		if (reported_size < 4096) {
-			printk(KERN_ERR "dnbd3: reported size by server is < 4096\n");
-			goto error;
-		}
-		dev->reported_size = reported_size;
-		set_capacity(dev->disk, dev->reported_size >> 9); /* 512 Byte blocks */
-	} else if (dev->reported_size != reported_size) {
-		printk(KERN_ERR "dnbd3: reported size by server is %llu but should be %llu\n", reported_size, dev->reported_size);
-	}
-
-	printk(KERN_DEBUG "dnbd3: connected to image %s, filesize %llu\n", dev->imgname, dev->reported_size);
-
-	mutex_unlock(&sock->lock);
-
-//	TODO add heartbeat
-	//	timer_setup(&dev->hb_timer, dnbd3_net_heartbeat, 0);
-	//	dev->hb_timer.expires = jiffies + HZ;
-	//	add_timer(&dev->hb_timer);
-
-	return 0;
-error:
-	if (sock->sock) {
-		sock_release(sock->sock);
-		sock->sock = NULL;
-	}
-	if (req1) {
-		kfree(req1);
-	}
-	mutex_unlock(&sock->lock);
-	return result;
-}
-
-int dnbd3_socket_disconnect(dnbd3_device_t *dev, dnbd3_sock *sock)
-{
-	printk(KERN_DEBUG "dnbd3: socket disconnect device %i\n", dev->minor);
-	mutex_lock(&sock->lock);
-
-	// clear heartbeat timer
-//	del_timer(&dev->hb_timer);
-
-
-	if (sock->sock) {
-		kernel_sock_shutdown(sock->sock, SHUT_RDWR);
-	}
-
-	// clear socket
-	if (sock->sock) {
-		sock_release(sock->sock);
-		sock->sock = NULL;
-	}
-
-	mutex_unlock(&sock->lock);
-	mutex_destroy(&sock->lock);
-	return 0;
-}
-
-int dnbd3_net_disconnect(struct dnbd3_device_t *dev) {
-	int i;
-	int result;
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
-		if (dev->socks[i].sock) {
-			if (dnbd3_socket_disconnect(dev, &dev->socks[i])) {
-				result = -EIO;
-			}
-		}
-	}
-	return result;
-}
-
-
-static void printHost(struct dnbd3_host_t *host, char *msg)
-{
-	if (host->type == HOST_IP4) {
-		printk(KERN_INFO "dnbd3: %s %pI4:%d", msg, host->addr, host->port);
-	} else {
-		printk(KERN_INFO "dnbd3: %s [%pI6]:%d", msg, host->addr, host->port);
-	}
-}
-
-static void printServerList(struct dnbd3_device_t *dev)
-{
-	int i;
-	printHost(&dev->initial_server.host, "initial server is");
-	for (i = 0; i < NUMBER_SERVERS; i++) {
-		if (dev->alt_servers[i].host.addr[0] != 0) {
-			printHost(&dev->alt_servers[i].host, "alternative server is");
-		}
-	}
-}
-
-static int dnbd3_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg)
-{
-	int result = -100;
-	dnbd3_device_t *dev = bdev->bd_disk->private_data;
-	char *imgname = NULL;
-	dnbd3_ioctl_t *msg = NULL;
-	int i;
-
-	printk(KERN_DEBUG "dnbd3: ioctl device %i, cmd %i, arg %lu\n", dev->minor, cmd, arg);
-	//unsigned long irqflags;
-
-//	while (dev->disconnecting) {
-//		// do nothing
-//	}
-
-	if (arg != 0) {
-		msg = kmalloc(sizeof(*msg), GFP_KERNEL);
-		if (msg == NULL) return -ENOMEM;
-		if (copy_from_user((char *)msg, (char *)arg, 2) != 0 || msg->len != sizeof(*msg)) {
-			result = -ENOEXEC;
-			goto cleanup_return;
-		}
-		if (copy_from_user((char *)msg, (char *)arg, sizeof(*msg)) != 0) {
-			result = -ENOENT;
-			goto cleanup_return;
-		}
-		if (msg->imgname != NULL && msg->imgnamelen > 0) {
-			imgname = kmalloc(msg->imgnamelen + 1, GFP_KERNEL);
-			if (imgname == NULL) {
-				result = -ENOMEM;
-				goto cleanup_return;
-			}
-			if (copy_from_user(imgname, msg->imgname, msg->imgnamelen) != 0) {
-				result = -ENOENT;
-				goto cleanup_return;
-			}
-			imgname[msg->imgnamelen] = '\0';
-
-			printk(KERN_DEBUG "dnbd3: ioctl image name of len %i is %s\n", (int)msg->imgnamelen, imgname);
-		}
-	}
-
-	switch (cmd) {
-	case IOCTL_OPEN:
-		printk(KERN_DEBUG "dnbd3: ioctl open\n");
-		if (dev->imgname != NULL) {
-			result = -EBUSY;
-		} else if (imgname == NULL) {
-			result = -EINVAL;
-		} else if (msg == NULL) {
-			result = -EINVAL;
-		} else {
-			if (sizeof(msg->host) != sizeof(dev->initial_server.host)) {
-				printk(KERN_INFO "dnbd3: odd size bug#1 triggered in ioctl\n");
-			}
-			memcpy(&dev->initial_server.host, &msg->host, sizeof(msg->host));
-			dev->initial_server.failures = 0;
-//			memcpy(&dev->initial_server, &dev->cur_server, sizeof(dev->initial_server));
-			dev->imgname = imgname;
-			dev->rid = msg->rid;
-			dev->use_server_provided_alts = msg->use_server_provided_alts;
-			// Forget all alt servers on explicit connect, set first alt server to initial server
-			memset(dev->alt_servers, 0, sizeof(dev->alt_servers[0])*NUMBER_SERVERS);
-			memcpy(dev->alt_servers, &dev->initial_server, sizeof(dev->alt_servers[0]));
-//#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
-//			if (blk_queue->backing_dev_info != NULL) {
-//				blk_queue->backing_dev_info->ra_pages = (msg->read_ahead_kb * 1024) / PAGE_SIZE;
-//			}
-//#else
-//			blk_queue->backing_dev_info.ra_pages = (msg->read_ahead_kb * 1024) / PAGE_SIZE;
-//#endif
-
-
-			dev->socks[0].server = &dev->initial_server;
-			if (dnbd3_socket_connect(dev, &dev->socks[0]) == 0) {
-				printServerList(dev);
-				result = 0;
-				imgname = NULL; // Prevent kfree at the end
-			} else {
-				printk(KERN_ERR "dnbd3: failed to connect to initial server\n");
-				result = -ENOENT;
-				dev->imgname = NULL;
-				dev->socks[0].server = NULL;
-			}
-
-		}
-		break;
-
-	case IOCTL_CLOSE:
-		printk(KERN_DEBUG "dnbd3: ioctl close\n");
-		dnbd3_blk_fail_all_requests(dev);
-		dnbd3_net_disconnect(dev);
-		dnbd3_blk_fail_all_requests(dev);
-		set_capacity(dev->disk, 0);
-		if (dev->imgname) {
-			kfree(dev->imgname);
-			dev->imgname = NULL;
-		}
-		break;
-
-	case IOCTL_SWITCH:
-		printk(KERN_DEBUG "dnbd3: ioctl switch\n");
-		result = -EINVAL;
-		break;
-
-	case IOCTL_ADD_SRV:
-	case IOCTL_REM_SRV:
-		printk(KERN_DEBUG "dnbd3: ioctl add/rem srv\n");
-		if (dev->imgname == NULL) {
-			result = -ENOENT;
-		} else if (dev->new_servers_num >= NUMBER_SERVERS) {
-			result = -EAGAIN;
-		} else if (msg == NULL) {
-			result = -EINVAL;
-		} else {
-			memcpy(&dev->new_servers[dev->new_servers_num].host, &msg->host, sizeof(msg->host));
-			dev->new_servers[dev->new_servers_num].failures = (cmd == IOCTL_ADD_SRV ? 0 : 1); // 0 = ADD, 1 = REM
-			++dev->new_servers_num;
-			result = 0;
-		}
-		break;
-
-	case BLKFLSBUF:
-		printk(KERN_DEBUG "dnbd3: ioctl blkflsbuf\n");
-		result = 0;
-		break;
-
-	default:
-		printk(KERN_DEBUG "dnbd3: ioctl unhandled cmd %d\n", cmd);
-		result = -EIO;
-		break;
-	}
-
-cleanup_return:
-	if (msg) kfree(msg);
-	if (imgname) kfree(imgname);
-	return result;
-
-}
-
-
-
-struct block_device_operations dnbd3_fops =
-{
-	.owner = THIS_MODULE,
-	.ioctl = dnbd3_ioctl,
-	.compat_ioctl =	dnbd3_ioctl,
-};
-
-
diff --git a/src/kernel/block.h b/src/kernel/block.h
deleted file mode 100644
index 49055d5..0000000
--- a/src/kernel/block.h
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * block.h
- *
- *  Created on: Jun 26, 2019
- *      Author: fred
- */
-
-#ifndef SRC_KERNEL_BLOCK_H_
-#define SRC_KERNEL_BLOCK_H_
-
-#define init_msghdr(h) do { \
-        h.msg_name = NULL; \
-        h.msg_namelen = 0; \
-        h.msg_control = NULL; \
-        h.msg_controllen = 0; \
-        h.msg_flags = MSG_WAITALL | MSG_NOSIGNAL; \
-	} while (0)
-
-//int dnbd3_net_connect(dnbd3_device_t *dev);
-
-int dnbd3_net_disconnect(dnbd3_device_t *dev);
-
-extern struct block_device_operations dnbd3_fops;
-
-
-#endif /* SRC_KERNEL_BLOCK_H_ */
diff --git a/src/kernel/core.c b/src/kernel/core.c
index db1f6de..48f809b 100644
--- a/src/kernel/core.c
+++ b/src/kernel/core.c
@@ -48,27 +48,298 @@
 #include <asm/types.h>
 
 #include "dnbd3.h"
-#include "clientconfig.h"
 #include "sysfs.h"
-#include "block.h"
-#include "mq.h"
+#include "clientconfig.h"
+#include "net.h"
+
+#define DNBD3_CMD_REQUEUED 1
 
 DEFINE_IDR(dnbd3_index_idr);
 DEFINE_MUTEX(dnbd3_index_mutex);
 
 static unsigned int max_devs = NUMBER_DEVICES;
-static dnbd3_device_t *dnbd3_device;
+static dnbd3_device *device;
 int major;
 
 
+static void dnbd3_requeue_cmd(struct dnbd3_cmd *cmd)
+{
+	struct request *req = blk_mq_rq_from_pdu(cmd);
+
+	if (!test_and_set_bit(DNBD3_CMD_REQUEUED, &cmd->flags)) {
+		blk_mq_requeue_request(req, true);
+	}
+}
+
+static int dnbd3_handle_cmd(struct dnbd3_cmd *cmd, int index)
+{
+	struct request *req = blk_mq_rq_from_pdu(cmd);
+	struct dnbd3_device *dev = cmd->dnbd3;
+	struct dnbd3_sock *sock;
+	int ret = -1;
+
+	printk(KERN_DEBUG "dnbd3: handle request at position %lu and size %d, device %i\n", blk_rq_pos(req), blk_rq_bytes(req), dev->minor);
+
+//	if (index >= 1) { // TODO use next server with good rtt for this request
+//		printk(KERN_INFO "dnbd3: index is %d", index);
+//		dev_err_ratelimited(disk_to_dev(dev->disk), "attempted send on invalid socket\n");
+//		blk_mq_start_request(req);
+//		return -EINVAL;
+//	}
+
+	sock = &dev->socks[index];
+	if (!sock->sock) {
+		printk(KERN_INFO "dnbd3: index is %d but no socket was found\n", index);
+		dev_err_ratelimited(disk_to_dev(dev->disk), "attempted send on invalid socket\n");
+		blk_mq_start_request(req);
+		return -EINVAL;
+	}
+
+
+	cmd->status = BLK_STS_OK;
+
+again:
+
+
+	mutex_lock(&sock->lock);
+	if (unlikely(!sock->sock)) {
+		mutex_unlock(&sock->lock);
+		printk(KERN_DEBUG "dnbd3: not connected\n");
+		return -EIO;
+	}
+
+	blk_mq_start_request(req);
+	if (unlikely(sock->pending && sock->pending != req)) {
+		dnbd3_requeue_cmd(cmd);
+		ret = 0;
+		goto out;
+	}
+
+	ret = dnbd3_send_request(dev, sock, blk_mq_rq_from_pdu(cmd));
+	if (ret == -EAGAIN) {
+		dev_err_ratelimited(disk_to_dev(dev->disk), "request send failed, requeueing\n");
+		dnbd3_requeue_cmd(cmd);
+		ret = 0;
+	}
+out:
+	mutex_unlock(&sock->lock);
+	return ret;
+}
+
+static blk_status_t dnbd3_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd)
+{
+	struct dnbd3_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
+	int ret;
+	struct dnbd3_device *dev = cmd->dnbd3;
+
+	printk(KERN_DEBUG "dnbd3: queue request device %i\n", dev->minor);
+
 
-static int dnbd3_add_device(dnbd3_device_t *dev, int minor)
+	mutex_lock(&cmd->lock);
+	clear_bit(DNBD3_CMD_REQUEUED, &cmd->flags);
+
+
+	ret = dnbd3_handle_cmd(cmd, hctx->queue_num);
+	if (ret < 0) {
+		ret = BLK_STS_IOERR;
+	} else if (!ret) {
+		ret = BLK_STS_OK;
+	}
+	mutex_unlock(&cmd->lock);
+
+	return ret;
+}
+
+static void dnbd3_complete_rq(struct request *req)
+{
+	printk(KERN_DEBUG "dnbd3: dnbd3_complete_rq\n");
+
+}
+
+static int dnbd3_init_request(struct blk_mq_tag_set *set, struct request *rq, unsigned int hctx_idx, unsigned int numa_node)
+{
+	struct dnbd3_cmd *cmd = blk_mq_rq_to_pdu(rq);
+	cmd->dnbd3 = set->driver_data;
+	cmd->flags = 0;
+	mutex_init(&cmd->lock);
+	return 0;
+}
+static enum blk_eh_timer_return dnbd3_xmit_timeout(struct request *req, bool reserved)
+{
+	printk(KERN_DEBUG "dnbd3: dnbd3_xmit_timeout\n");
+	return BLK_EH_DONE;
+}
+
+
+static struct blk_mq_ops dnbd3_mq_ops = {
+	.queue_rq = dnbd3_queue_rq,
+	.complete = dnbd3_complete_rq,
+	.init_request = dnbd3_init_request,
+	.timeout = dnbd3_xmit_timeout,
+};
+
+
+
+
+static void dnbd3_blk_fail_all_requests(dnbd3_device *dev)
+{
+	printk(KERN_DEBUG "dnbd3: fail all requests device %i\n", dev->minor);
+}
+
+
+
+static int dnbd3_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg)
+{
+	int result = -100;
+	dnbd3_device *dev = bdev->bd_disk->private_data;
+	char *imgname = NULL;
+	dnbd3_ioctl_t *msg = NULL;
+
+	printk(KERN_DEBUG "dnbd3: ioctl device %i, cmd %i, arg %lu\n", dev->minor, cmd, arg);
+	//unsigned long irqflags;
+
+//	while (dev->disconnecting) {
+//		// do nothing
+//	}
+
+	if (arg != 0) {
+		msg = kmalloc(sizeof(*msg), GFP_KERNEL);
+		if (msg == NULL) return -ENOMEM;
+		if (copy_from_user((char *)msg, (char *)arg, 2) != 0 || msg->len != sizeof(*msg)) {
+			result = -ENOEXEC;
+			goto cleanup_return;
+		}
+		if (copy_from_user((char *)msg, (char *)arg, sizeof(*msg)) != 0) {
+			result = -ENOENT;
+			goto cleanup_return;
+		}
+		if (msg->imgname != NULL && msg->imgnamelen > 0) {
+			imgname = kmalloc(msg->imgnamelen + 1, GFP_KERNEL);
+			if (imgname == NULL) {
+				result = -ENOMEM;
+				goto cleanup_return;
+			}
+			if (copy_from_user(imgname, msg->imgname, msg->imgnamelen) != 0) {
+				result = -ENOENT;
+				goto cleanup_return;
+			}
+			imgname[msg->imgnamelen] = '\0';
+
+			printk(KERN_DEBUG "dnbd3: ioctl image name of len %i is %s\n", (int)msg->imgnamelen, imgname);
+		}
+	}
+
+	mutex_lock(&dev->device_lock);
+	switch (cmd) {
+	case IOCTL_OPEN:
+		printk(KERN_DEBUG "dnbd3: ioctl open\n");
+		if (dev->imgname != NULL) {
+			result = -EBUSY;
+		} else if (imgname == NULL) {
+			result = -EINVAL;
+		} else if (msg == NULL) {
+			result = -EINVAL;
+		} else {
+			if (sizeof(msg->host) != sizeof(dev->initial_server.host)) {
+				printk(KERN_INFO "dnbd3: odd size bug#1 triggered in ioctl\n");
+			}
+			memcpy(&dev->initial_server.host, &msg->host, sizeof(msg->host));
+			dev->initial_server.failures = 0;
+//			memcpy(&dev->initial_server, &dev->cur_server, sizeof(dev->initial_server));
+			dev->imgname = imgname;
+			dev->rid = msg->rid;
+			dev->use_server_provided_alts = msg->use_server_provided_alts;
+			// Forget all alt servers on explicit connect, set first alt server to initial server
+			memset(dev->alt_servers, 0, sizeof(dev->alt_servers[0])*NUMBER_SERVERS);
+			memcpy(dev->alt_servers, &dev->initial_server, sizeof(dev->alt_servers[0]));
+//#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
+//			if (blk_queue->backing_dev_info != NULL) {
+//				blk_queue->backing_dev_info->ra_pages = (msg->read_ahead_kb * 1024) / PAGE_SIZE;
+//			}
+//#else
+//			blk_queue->backing_dev_info.ra_pages = (msg->read_ahead_kb * 1024) / PAGE_SIZE;
+//#endif
+
+
+			result = dnbd3_net_connect(dev);
+			imgname = NULL;
+		}
+		break;
+
+	case IOCTL_CLOSE:
+		printk(KERN_DEBUG "dnbd3: ioctl close\n");
+		dnbd3_blk_fail_all_requests(dev);
+		dnbd3_net_disconnect(dev);
+		dnbd3_blk_fail_all_requests(dev);
+		set_capacity(dev->disk, 0);
+		if (dev->imgname) {
+			kfree(dev->imgname);
+			dev->imgname = NULL;
+		}
+		break;
+
+	case IOCTL_SWITCH:
+		printk(KERN_DEBUG "dnbd3: ioctl switch\n");
+		result = -EINVAL;
+		break;
+
+	case IOCTL_ADD_SRV:
+	case IOCTL_REM_SRV:
+		printk(KERN_DEBUG "dnbd3: ioctl add/rem srv\n");
+		if (dev->imgname == NULL) {
+			result = -ENOENT;
+		} else if (dev->new_servers_num >= NUMBER_SERVERS) {
+			result = -EAGAIN;
+		} else if (msg == NULL) {
+			result = -EINVAL;
+		} else {
+			memcpy(&dev->new_servers[dev->new_servers_num].host, &msg->host, sizeof(msg->host));
+			dev->new_servers[dev->new_servers_num].failures = (cmd == IOCTL_ADD_SRV ? 0 : 1); // 0 = ADD, 1 = REM
+			++dev->new_servers_num;
+			result = 0;
+		}
+		break;
+
+	case BLKFLSBUF:
+		printk(KERN_DEBUG "dnbd3: ioctl blkflsbuf\n");
+		result = 0;
+		break;
+
+	default:
+		printk(KERN_DEBUG "dnbd3: ioctl unhandled cmd %d\n", cmd);
+		result = -EIO;
+		break;
+	}
+	mutex_unlock(&dev->device_lock);
+cleanup_return:
+	if (msg) kfree(msg);
+	if (imgname) kfree(imgname);
+	return result;
+
+}
+
+
+
+static struct block_device_operations dnbd3_fops =
+{
+	.owner = THIS_MODULE,
+	.ioctl = dnbd3_ioctl,
+	.compat_ioctl =	dnbd3_ioctl,
+};
+
+
+
+
+
+int dnbd3_add_device(dnbd3_device *dev, int minor)
 {
 	struct gendisk *disk;
 	struct request_queue *q;
 	int err = -ENOMEM;
 	printk(KERN_DEBUG "dnbd3: adding device %i\n", minor);
 
+	mutex_init(&dev->device_lock);
+	mutex_lock(&dev->device_lock);
 
 	disk = alloc_disk(1);
 	if (!disk) {
@@ -129,6 +400,9 @@ static int dnbd3_add_device(dnbd3_device_t *dev, int minor)
 	printk(KERN_DEBUG "dnbd3: add disk device %s\n", disk->disk_name);
 	add_disk(disk);
 	dnbd3_sysfs_init(dev);
+
+
+	mutex_unlock(&dev->device_lock);
 	return minor;
 
 out_free_tags:
@@ -139,12 +413,14 @@ out_free_disk:
 	put_disk(disk);
 out_free_dnbd3:
 	kfree(dev);
+	mutex_unlock(&dev->device_lock);
 	printk(KERN_DEBUG "dnbd3: destroy device %i\n", minor);
 	return err;
 }
 
 
 
+
 static int __init dnbd3_init(void)
 {
 	int i;
@@ -156,8 +432,8 @@ static int __init dnbd3_init(void)
 	}
 
 
-	dnbd3_device = kcalloc(max_devs, sizeof(*dnbd3_device), GFP_KERNEL);
-	if (!dnbd3_device) {
+	device = kcalloc(max_devs, sizeof(*device), GFP_KERNEL);
+	if (!device) {
 		printk(KERN_ERR "dnbd3: failed to create dnbd3 device\n");
 		return -ENOMEM;
 	}
@@ -174,7 +450,7 @@ static int __init dnbd3_init(void)
 	// add MAX_NUMBER_DEVICES devices
 	mutex_lock(&dnbd3_index_mutex);
 	for (i = 0; i < max_devs; i++) {
-		dnbd3_add_device(&dnbd3_device[i], i);
+		dnbd3_add_device(&device[i], i);
 	}
 	mutex_unlock(&dnbd3_index_mutex);
 
@@ -187,13 +463,13 @@ static int __init dnbd3_init(void)
 static int dnbd3_exit_cb(int id, void *ptr, void *data)
 {
 	struct list_head *list = (struct list_head *)data;
-	struct dnbd3_device_t *dnbd3 = ptr;
+	struct dnbd3_device *dnbd3 = ptr;
 
 	list_add_tail(&dnbd3->list, list);
 	return 0;
 }
 
-static void dnbd3_dev_remove(struct dnbd3_device_t *dnbd3)
+static void dnbd3_dev_remove(struct dnbd3_device *dnbd3)
 {
 	struct gendisk *disk = dnbd3->disk;
 	struct request_queue *q;
@@ -209,7 +485,7 @@ static void dnbd3_dev_remove(struct dnbd3_device_t *dnbd3)
 	}
 }
 
-static void dnbd3_put(struct dnbd3_device_t *dnbd3)
+static void dnbd3_put(struct dnbd3_device *dnbd3)
 {
 	mutex_lock(&dnbd3_index_mutex);
 	idr_remove(&dnbd3_index_idr, dnbd3->minor);
@@ -220,7 +496,7 @@ static void dnbd3_put(struct dnbd3_device_t *dnbd3)
 
 static void __exit dnbd3_exit(void)
 {
-	dnbd3_device_t *dnbd3;
+	dnbd3_device *dnbd3;
 	LIST_HEAD(del_list);
 	printk(KERN_DEBUG "dnbd3: stopping kernel module\n");
 
@@ -229,7 +505,7 @@ static void __exit dnbd3_exit(void)
 	mutex_unlock(&dnbd3_index_mutex);
 
 	while (!list_empty(&del_list)) {
-		dnbd3 = list_first_entry(&del_list, struct dnbd3_device_t, list);
+		dnbd3 = list_first_entry(&del_list, struct dnbd3_device, list);
 		dnbd3_sysfs_exit(dnbd3);
 		list_del_init(&dnbd3->list);
 		dnbd3_put(dnbd3);
@@ -238,7 +514,7 @@ static void __exit dnbd3_exit(void)
 	idr_destroy(&dnbd3_index_idr);
 	unregister_blkdev(major, "dnbd3");
 
-	kfree(dnbd3_device);
+	kfree(device);
 
 	printk(KERN_INFO "dnbd3: stopped kernel module\n");
 }
diff --git a/src/kernel/dnbd3.h b/src/kernel/dnbd3.h
index 7ad6b2f..57f26f6 100644
--- a/src/kernel/dnbd3.h
+++ b/src/kernel/dnbd3.h
@@ -33,22 +33,27 @@
 
 #define NUMBER_CONNECTIONS 4
 
-typedef struct dnbd3_server_t {
+typedef struct dnbd3_server {
 	dnbd3_host_t host;
 	uint64_t rtts[4];		// Last four round trip time measurements in microsecond
 	uint16_t protocol_version;	// dnbd3 protocol version of this server
 	uint8_t failures;			// How many times the server was unreachable
-} dnbd3_server_t;
+} dnbd3_server;
 
 
 typedef struct dnbd3_sock {
 	struct socket *sock;
 	struct mutex lock;
 	struct request *pending;
-	struct dnbd3_server_t *server;
+	struct dnbd3_server *server;
+	uint32_t heartbeat_count;
+	uint8_t panic, discover, panic_count;
+//	struct dnbd3_device *container_of;
+	struct work_struct keepalive;
+	struct timer_list keepalive_timer;
 } dnbd3_sock;
 
-typedef struct dnbd3_device_t {
+typedef struct dnbd3_device {
 	int minor;
 	struct blk_mq_tag_set tag_set;
 	struct list_head list;
@@ -59,28 +64,32 @@ typedef struct dnbd3_device_t {
 	// sysfs
 	struct kobject kobj;
 
+	struct mutex device_lock;
+
 	// network
 	dnbd3_sock socks[NUMBER_CONNECTIONS];
 	char *imgname;
 //	struct socket *sock;
 //	struct mutex socket_lock;
 //	struct request *pending;
-	dnbd3_server_t initial_server;
+	dnbd3_server initial_server;
 //	dnbd3_server_t cur_server, initial_server;
 //	uint64_t cur_rtt;
 //	serialized_buffer_t payload_buffer;
-	dnbd3_server_t alt_servers[NUMBER_SERVERS]; // array of alt servers
+	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
 //	uint8_t discover, panic, disconnecting, update_available, panic_count;
 	uint8_t update_available;
 	uint8_t use_server_provided_alts;
 	uint16_t rid;
-	uint32_t heartbeat_count;
+//	uint32_t heartbeat_count;
 	uint64_t reported_size;
 	// server switch
 //	struct socket *better_sock;
 
+	struct work_struct discovery; // if in irq and need to send request
+	struct timer_list discovery_timer;
 
 	// process
 //	struct task_struct * thread_send;
@@ -93,11 +102,11 @@ typedef struct dnbd3_device_t {
 //	struct list_head request_queue_send;
 //	struct list_head request_queue_receive;
 
-} dnbd3_device_t;
+} dnbd3_device;
 
 
 typedef struct dnbd3_cmd {
-	struct dnbd3_device_t *dnbd3;
+	struct dnbd3_device *dnbd3;
 	struct mutex lock;
 	int index;
 	int cookie;
diff --git a/src/kernel/mq.c b/src/kernel/mq.c
deleted file mode 100644
index 98e6e14..0000000
--- a/src/kernel/mq.c
+++ /dev/null
@@ -1,237 +0,0 @@
-/*
- * mq.c
- *
- *  Created on: Jun 26, 2019
- *      Author: fred
- */
-
-#include <net/sock.h>
-
-#include "mq.h"
-#include "block.h"
-
-#define DNBD3_CMD_REQUEUED 1
-
-
-#define dnbd3_priv_to_cmd(req)        ((req)->cmd_flags >> REQ_FLAG_BITS)
-
-static int dnbd3_send_cmd(struct dnbd3_device_t *dev, struct dnbd3_sock *sock, struct dnbd3_cmd *cmd, int index)
-{
-	struct request *req = blk_mq_rq_from_pdu(cmd);
-	dnbd3_request_t dnbd3_request;
-	dnbd3_reply_t dnbd3_reply;
-	struct msghdr msg;
-	struct kvec iov;
-	struct req_iterator iter;
-	struct bio_vec bvec_inst;
-	struct bio_vec *bvec = &bvec_inst;
-	sigset_t blocked, oldset;
-	void *kaddr;
-	int result;
-	sock->pending = req;
-	init_msghdr(msg);
-
-	dnbd3_request.magic = dnbd3_packet_magic;
-
-	switch (req_op(req)) {
-//	case REQ_OP_DISCARD:
-//		printk(KERN_DEBUG "dnbd3: request operation discard on device %d\n", dev->minor);
-//		break;
-//	case REQ_OP_FLUSH:
-//		printk(KERN_DEBUG "dnbd3: request operation flush on device %d\n", dev->minor);
-//		break;
-//	case REQ_OP_WRITE:
-//		printk(KERN_DEBUG "dnbd3: request operation write on device %d\n", dev->minor);
-//		break;
-	case REQ_OP_READ:
-		printk(KERN_DEBUG "dnbd3: request operation read on device %d\n", dev->minor);
-		dnbd3_request.cmd = CMD_GET_BLOCK;
-		dnbd3_request.offset = blk_rq_pos(req) << 9; // *512
-		dnbd3_request.size = blk_rq_bytes(req); // bytes left to complete entire request
-		break;
-	case REQ_OP_DRV_IN:
-		printk(KERN_DEBUG "dnbd3: request operation driver in on device %d\n", dev->minor);
-		dnbd3_request.cmd = dnbd3_priv_to_cmd(req);
-		dnbd3_request.size = 0;
-		break;
-
-	default:
-		return -EIO;
-	}
-
-	dnbd3_request.handle = (uint64_t)(uintptr_t)req; // Double cast to prevent warning on 32bit
-	fixup_request(dnbd3_request);
-	iov.iov_base = &dnbd3_request;
-	iov.iov_len = sizeof(dnbd3_request);
-	if (kernel_sendmsg(sock->sock, &msg, &iov, 1, sizeof(dnbd3_request)) != sizeof(dnbd3_request)) {
-		printk(KERN_ERR "dnbd3: connection to server lost\n");
-		result = -EIO;
-		goto error;
-	}
-
-	// receive net reply
-	iov.iov_base = &dnbd3_reply;
-	iov.iov_len = sizeof(dnbd3_reply);
-	result = kernel_recvmsg(sock->sock, &msg, &iov, 1, sizeof(dnbd3_reply), msg.msg_flags);
-	if (!result) {
-		printk(KERN_ERR "dnbd3: connection to server lost\n");
-		result = -EIO;
-		goto error;
-
-	}
-	fixup_reply(dnbd3_reply);
-
-	// check error
-	if (dnbd3_reply.magic != dnbd3_packet_magic) {
-		printk(KERN_ERR "dnbd3: wrong magic packet\n");
-		result = -EIO;
-		goto error;
-	}
-
-	if (dnbd3_reply.cmd != CMD_GET_BLOCK) {
-		printk(KERN_ERR "dnbd3: command was %d\n", dnbd3_reply.cmd);
-		result = -EIO;
-		goto error;
-	}
-
-
-
-	rq_for_each_segment(bvec_inst, req, iter) {
-		siginitsetinv(&blocked, sigmask(SIGKILL));
-		sigprocmask(SIG_SETMASK, &blocked, &oldset);
-
-		kaddr = kmap(bvec->bv_page) + bvec->bv_offset;
-		iov.iov_base = kaddr;
-		iov.iov_len = bvec->bv_len;
-		if (kernel_recvmsg(sock->sock, &msg, &iov, 1, bvec->bv_len, msg.msg_flags) != bvec->bv_len) {
-			kunmap(bvec->bv_page);
-			sigprocmask(SIG_SETMASK, &oldset, NULL );
-			printk(KERN_ERR "dnbd3: could not receive form net to block layer\n");
-			goto error;
-		}
-		kunmap(bvec->bv_page);
-
-		sigprocmask(SIG_SETMASK, &oldset, NULL );
-	}
-	blk_mq_end_request(req, 0);
-	sock->pending = NULL;
-error:
-	return result;
-}
-
-static void dnbd3_requeue_cmd(struct dnbd3_cmd *cmd)
-{
-	struct request *req = blk_mq_rq_from_pdu(cmd);
-
-	if (!test_and_set_bit(DNBD3_CMD_REQUEUED, &cmd->flags)) {
-		blk_mq_requeue_request(req, true);
-	}
-}
-
-static int dnbd3_handle_cmd(struct dnbd3_cmd *cmd, int index)
-{
-	struct request *req = blk_mq_rq_from_pdu(cmd);
-	struct dnbd3_device_t *dev = cmd->dnbd3;
-	struct dnbd3_sock *sock;
-	int ret = -1;
-
-	printk(KERN_DEBUG "dnbd3: handle request at position %lu and size %d, device %i\n", blk_rq_pos(req), blk_rq_bytes(req), dev->minor);
-
-//	if (index >= 1) { // TODO use next server with good rtt for this request
-//		printk(KERN_INFO "dnbd3: index is %d", index);
-//		dev_err_ratelimited(disk_to_dev(dev->disk), "attempted send on invalid socket\n");
-//		blk_mq_start_request(req);
-//		return -EINVAL;
-//	}
-
-	sock = &dev->socks[index];
-	if (!sock->sock) {
-		printk(KERN_INFO "dnbd3: index is %d but no socket was found\n", index);
-		dev_err_ratelimited(disk_to_dev(dev->disk), "attempted send on invalid socket\n");
-		blk_mq_start_request(req);
-		return -EINVAL;
-	}
-
-
-	cmd->status = BLK_STS_OK;
-
-again:
-
-
-	mutex_lock(&sock->lock);
-	if (unlikely(!sock->sock)) {
-		mutex_unlock(&sock->lock);
-		printk(KERN_DEBUG "dnbd3: not connected\n");
-		return -EIO;
-	}
-
-	blk_mq_start_request(req);
-	if (unlikely(sock->pending && sock->pending != req)) {
-		dnbd3_requeue_cmd(cmd);
-		ret = 0;
-		goto out;
-	}
-
-	ret = dnbd3_send_cmd(dev, sock, cmd, index);
-	if (ret == -EAGAIN) {
-		dev_err_ratelimited(disk_to_dev(dev->disk), "request send failed, requeueing\n");
-		dnbd3_requeue_cmd(cmd);
-		ret = 0;
-	}
-out:
-	mutex_unlock(&sock->lock);
-	return ret;
-}
-
-static blk_status_t dnbd3_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd)
-{
-	struct dnbd3_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
-	int ret;
-	struct dnbd3_device_t *dev = cmd->dnbd3;
-
-	printk(KERN_DEBUG "dnbd3: queue request device %i\n", dev->minor);
-
-
-	mutex_lock(&cmd->lock);
-	clear_bit(DNBD3_CMD_REQUEUED, &cmd->flags);
-
-
-	ret = dnbd3_handle_cmd(cmd, hctx->queue_num);
-	if (ret < 0) {
-		ret = BLK_STS_IOERR;
-	} else if (!ret) {
-		ret = BLK_STS_OK;
-	}
-	mutex_unlock(&cmd->lock);
-
-	return ret;
-}
-
-static void dnbd3_complete_rq(struct request *req)
-{
-	printk(KERN_DEBUG "dnbd3: dnbd3_complete_rq\n");
-
-}
-
-static int dnbd3_init_request(struct blk_mq_tag_set *set, struct request *rq, unsigned int hctx_idx, unsigned int numa_node)
-{
-	struct dnbd3_cmd *cmd = blk_mq_rq_to_pdu(rq);
-	cmd->dnbd3 = set->driver_data;
-	cmd->flags = 0;
-	mutex_init(&cmd->lock);
-	return 0;
-}
-static enum blk_eh_timer_return dnbd3_xmit_timeout(struct request *req, bool reserved)
-{
-	printk(KERN_DEBUG "dnbd3: dnbd3_xmit_timeout\n");
-	return BLK_EH_DONE;
-}
-
-
-struct blk_mq_ops dnbd3_mq_ops = {
-	.queue_rq = dnbd3_queue_rq,
-	.complete = dnbd3_complete_rq,
-	.init_request = dnbd3_init_request,
-	.timeout = dnbd3_xmit_timeout,
-};
-
diff --git a/src/kernel/mq.h b/src/kernel/mq.h
deleted file mode 100644
index 9f3cde8..0000000
--- a/src/kernel/mq.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/*
- * mq.h
- *
- *  Created on: Jun 26, 2019
- *      Author: fred
- */
-
-#ifndef SRC_KERNEL_MQ_H_
-#define SRC_KERNEL_MQ_H_
-
-#include "dnbd3.h"
-
-extern struct blk_mq_ops dnbd3_mq_ops;
-
-
-#endif /* SRC_KERNEL_MQ_H_ */
diff --git a/src/kernel/net.c b/src/kernel/net.c
new file mode 100644
index 0000000..f44925f
--- /dev/null
+++ b/src/kernel/net.c
@@ -0,0 +1,528 @@
+/*
+ * 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.
+ *
+ */
+
+
+
+#include <net/sock.h>
+
+#include "dnbd3.h"
+#include "clientconfig.h"
+
+#define dnbd3_cmd_to_priv(req, cmd)   (req)->cmd_flags = REQ_OP_DRV_IN | ((cmd) << REQ_FLAG_BITS)
+#define dnbd3_priv_to_cmd(req)        ((req)->cmd_flags >> REQ_FLAG_BITS)
+#define dnbd3_req_op(req)             req_op(req)
+#define dnbd3_sock_create(af,type,proto,sock) sock_create_kern(&init_net, (af) == HOST_IP4 ? AF_INET : AF_INET6, type, proto, sock)
+
+#define KEEPALIVE_TIMER (TIMER_INTERVAL_KEEPALIVE_PACKET * (jiffies + HZ))
+#define DISCOVERY_TIMER (TIMER_INTERVAL_PROBE_NORMAL * (jiffies + HZ))
+
+#define init_msghdr(h) do { \
+        h.msg_name = NULL; \
+        h.msg_namelen = 0; \
+        h.msg_control = NULL; \
+        h.msg_controllen = 0; \
+        h.msg_flags = MSG_WAITALL | MSG_NOSIGNAL; \
+	} while (0)
+
+
+static void printHost(struct dnbd3_host_t *host, char *msg)
+{
+	if (host->type == HOST_IP4) {
+		printk(KERN_INFO "dnbd3: %s %pI4:%d\n", msg, host->addr, host->port);
+	} else {
+		printk(KERN_INFO "dnbd3: %s [%pI6]:%d\n", msg, host->addr, host->port);
+	}
+}
+
+static void printServerList(struct dnbd3_device *dev)
+{
+	int i;
+	printHost(&dev->initial_server.host, "initial server is");
+	for (i = 0; i < NUMBER_SERVERS; i++) {
+		if (dev->alt_servers[i].host.addr[0] != 0) {
+			printHost(&dev->alt_servers[i].host, "alternative server is");
+		}
+	}
+}
+
+int dnbd3_send_request(struct dnbd3_device *dev, struct dnbd3_sock *sock, struct request *req)
+{
+	dnbd3_request_t dnbd3_request;
+	dnbd3_reply_t dnbd3_reply;
+	struct msghdr msg;
+	struct kvec iov;
+	struct req_iterator iter;
+	struct bio_vec bvec_inst;
+	struct bio_vec *bvec = &bvec_inst;
+	sigset_t blocked, oldset;
+	void *kaddr;
+	int result, count, remaining;
+	uint16_t rid;
+	sock->pending = req;
+	init_msghdr(msg);
+
+	dnbd3_request.magic = dnbd3_packet_magic;
+
+	switch (req_op(req)) {
+//	case REQ_OP_DISCARD:
+//		printk(KERN_DEBUG "dnbd3: request operation discard on device %d\n", dev->minor);
+//		break;
+//	case REQ_OP_FLUSH:
+//		printk(KERN_DEBUG "dnbd3: request operation flush on device %d\n", dev->minor);
+//		break;
+//	case REQ_OP_WRITE:
+//		printk(KERN_DEBUG "dnbd3: request operation write on device %d\n", dev->minor);
+//		break;
+	case REQ_OP_READ:
+		printk(KERN_DEBUG "dnbd3: request operation read\n");
+		dnbd3_request.cmd = CMD_GET_BLOCK;
+		dnbd3_request.offset = blk_rq_pos(req) << 9; // *512
+		dnbd3_request.size = blk_rq_bytes(req); // bytes left to complete entire request
+		break;
+	case REQ_OP_DRV_IN:
+		printk(KERN_DEBUG "dnbd3: request operation driver in\n");
+		dnbd3_request.cmd = dnbd3_priv_to_cmd(req);
+		dnbd3_request.size = 0;
+		break;
+
+	default:
+		return -EIO;
+	}
+
+	dnbd3_request.handle = (uint64_t)(uintptr_t)req; // Double cast to prevent warning on 32bit
+	fixup_request(dnbd3_request);
+	iov.iov_base = &dnbd3_request;
+	iov.iov_len = sizeof(dnbd3_request);
+	if (kernel_sendmsg(sock->sock, &msg, &iov, 1, sizeof(dnbd3_request)) != sizeof(dnbd3_request)) {
+		printk(KERN_ERR "dnbd3: connection to server lost\n");
+		result = -EIO;
+		goto error;
+	}
+
+	// receive net reply
+	iov.iov_base = &dnbd3_reply;
+	iov.iov_len = sizeof(dnbd3_reply);
+	result = kernel_recvmsg(sock->sock, &msg, &iov, 1, sizeof(dnbd3_reply), msg.msg_flags);
+	if (!result) {
+		printk(KERN_ERR "dnbd3: connection to server lost\n");
+		result = -EIO;
+		goto error;
+
+	}
+	fixup_reply(dnbd3_reply);
+
+	// check error
+	if (dnbd3_reply.magic != dnbd3_packet_magic) {
+		printk(KERN_ERR "dnbd3: wrong magic packet\n");
+		result = -EIO;
+		goto error;
+	}
+
+	if (dnbd3_reply.cmd == 0) {
+		printk(KERN_ERR "dnbd3: command was 0\n");
+		result = -EIO;
+		goto error;
+	}
+
+
+	switch (dnbd3_reply.cmd) {
+	case CMD_GET_BLOCK:
+		rq_for_each_segment(bvec_inst, req, iter) {
+			siginitsetinv(&blocked, sigmask(SIGKILL));
+			sigprocmask(SIG_SETMASK, &blocked, &oldset);
+
+			kaddr = kmap(bvec->bv_page) + bvec->bv_offset;
+			iov.iov_base = kaddr;
+			iov.iov_len = bvec->bv_len;
+			if (kernel_recvmsg(sock->sock, &msg, &iov, 1, bvec->bv_len, msg.msg_flags) != bvec->bv_len) {
+				kunmap(bvec->bv_page);
+				sigprocmask(SIG_SETMASK, &oldset, NULL );
+				printk(KERN_ERR "dnbd3: could not receive form net to block layer\n");
+				goto error;
+			}
+			kunmap(bvec->bv_page);
+
+			sigprocmask(SIG_SETMASK, &oldset, NULL );
+		}
+		blk_mq_end_request(req, 0);
+		break;
+	case CMD_GET_SERVERS:
+		printk(KERN_DEBUG "dnbd3: get servers received\n");
+		mutex_lock(&dev->device_lock);
+		if (!dev->use_server_provided_alts) {
+			remaining = dnbd3_reply.size;
+			goto consume_payload;
+		}
+		dev->new_servers_num = 0;
+		count = MIN(NUMBER_SERVERS, dnbd3_reply.size / sizeof(dnbd3_server_entry_t));
+
+		if (count != 0) {
+			iov.iov_base = dev->new_servers;
+			iov.iov_len = count * sizeof(dnbd3_server_entry_t);
+			if (kernel_recvmsg(sock->sock, &msg, &iov, 1, (count * sizeof(dnbd3_server_entry_t)), msg.msg_flags) != (count * sizeof(dnbd3_server_entry_t))) {
+				printk(KERN_ERR "dnbd3: failed to get servers\n");
+				mutex_unlock(&dev->device_lock);
+				goto error;
+			}
+			dev->new_servers_num = count;
+		}
+		// If there were more servers than accepted, remove the remaining data from the socket buffer
+		remaining = dnbd3_reply.size - (count * sizeof(dnbd3_server_entry_t));
+consume_payload:
+		while (remaining > 0) {
+			count = MIN(sizeof(dnbd3_reply), remaining); // Abuse the reply struct as the receive buffer
+			iov.iov_base = &dnbd3_reply;
+			iov.iov_len = count;
+			result = kernel_recvmsg(sock->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags);
+			if (result <= 0) {
+				printk(KERN_ERR "dnbd3: failed to receive payload from get servers\n");
+				mutex_unlock(&dev->device_lock);
+				goto error;
+			}
+			result = 0;
+		}
+		mutex_unlock(&dev->device_lock);
+		break;
+	case CMD_LATEST_RID:
+		if (dnbd3_reply.size != 2) {
+			printk(KERN_ERR "dnbd3: failed to get latest rid, wrong size\n");
+			goto error;
+		}
+		printk(KERN_DEBUG "dnbd3: latest rid received\n");
+		iov.iov_base = &rid;
+		iov.iov_len = sizeof(rid);
+		if (kernel_recvmsg(sock->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags) <= 0) {
+			printk(KERN_ERR "dnbd3: failed to get latest rid\n");
+			goto error;
+		}
+		rid = net_order_16(rid);
+		printk("Latest rid of %s is %d (currently using %d)\n", dev->imgname, (int)rid, (int)dev->rid);
+		dev->update_available = (rid > dev->rid ? 1 : 0);
+		break;
+	case CMD_KEEPALIVE:
+		if (dnbd3_reply.size != 0) {
+			printk(KERN_ERR "dnbd3: got keep alive packet with payload\n");
+			goto error;
+		}
+		printk(KERN_DEBUG "dnbd3: keep alive received\n");
+		break;
+
+	default:
+		printk("ERROR: Unknown command (Receive)\n");
+		break;
+
+	}
+	sock->pending = NULL;
+error:
+	return result;
+}
+
+
+void dnbd3_keepalive(struct timer_list *arg)
+{
+	struct dnbd3_sock *sock = container_of(arg, struct dnbd3_sock, keepalive_timer);
+	printk(KERN_DEBUG "dnbd3: schedule keepalive\n");
+//	schedule_work(&sock->keepalive);
+	sock->keepalive_timer.expires = KEEPALIVE_TIMER;
+	add_timer(&sock->keepalive_timer);
+}
+
+static void keepalive(struct work_struct *work)
+{
+	struct dnbd3_sock *sock = container_of(work, struct dnbd3_sock, keepalive);
+	struct request *req;
+	mutex_lock(&sock->lock);
+	req = kmalloc(sizeof(struct request), GFP_ATOMIC );
+	// send keepalive
+	if (req) {
+		dnbd3_cmd_to_priv(req, CMD_KEEPALIVE);
+		dnbd3_send_request(NULL, sock, req); // we do not need the device for keepalive
+		kfree(req);
+	} else {
+		printk(KERN_WARNING "dnbd3: could not create keepalive request\n");
+	}
+	++sock->heartbeat_count;
+	mutex_unlock(&sock->lock);
+}
+
+void dnbd3_discovery(struct timer_list *arg)
+{
+	struct dnbd3_device *dev = container_of(arg, struct dnbd3_device, discovery_timer);
+	printk(KERN_DEBUG "dnbd3: schedule discovery\n");
+//	schedule_work(&dev->discovery);
+	dev->discovery_timer.expires = DISCOVERY_TIMER;
+	add_timer(&dev->discovery_timer);
+}
+
+static void discovery(struct work_struct *work)
+{
+	struct dnbd3_device *dev = container_of(work, struct dnbd3_device, discovery);
+	dnbd3_sock *sock = &dev->socks[0]; // we use the first sock for discovery
+	struct request *req;
+	mutex_lock(&sock->lock);
+	req = kmalloc(sizeof(struct request), GFP_ATOMIC );
+	// send keepalive
+	if (req) {
+		dnbd3_cmd_to_priv(req, CMD_GET_SERVERS);
+		dnbd3_send_request(NULL, sock, req); // we do not need the device for keepalive
+		kfree(req);
+	} else {
+		printk(KERN_WARNING "dnbd3: could not create get servers request\n");
+	}
+	mutex_unlock(&sock->lock);
+}
+
+
+static int dnbd3_socket_connect(dnbd3_device *dev, dnbd3_sock *sock)
+{
+	int result = -EIO;
+	struct request *req1 = NULL;
+	struct timeval timeout;
+	struct dnbd3_server *server = sock->server;
+	dnbd3_request_t dnbd3_request;
+	dnbd3_reply_t dnbd3_reply;
+	struct msghdr msg;
+	struct kvec iov[2];
+	uint16_t rid;
+	uint64_t reported_size;
+	char *name;
+	int mlen;
+	serialized_buffer_t payload_buffer;
+
+	printk(KERN_DEBUG "dnbd3: socket connect device %i\n", dev->minor);
+
+	mutex_init(&sock->lock);
+	mutex_lock(&sock->lock);
+	if (sock->pending) {
+		printk(KERN_DEBUG "dnbd3: socket still in request\n");
+		while (sock->pending)
+			schedule();
+	}
+	if (server->host.port == 0 || server->host.type == 0) {
+		printk(KERN_ERR "dnbd3: host or port not set\n");
+		goto error;
+	}
+	if (sock->sock) {
+		printk(KERN_WARNING "dnbd3: socket already connected\n");
+		goto error;
+	}
+
+	timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DATA;
+	timeout.tv_usec = 0;
+
+	req1 = kmalloc(sizeof(*req1), GFP_ATOMIC );
+	if (!req1) {
+		printk(KERN_ERR "dnbd3: kmalloc failed\n");
+		goto error;
+	}
+
+	init_msghdr(msg);
+
+	if (dnbd3_sock_create(server->host.type, SOCK_STREAM, IPPROTO_TCP, &sock->sock) < 0) {
+		printk(KERN_ERR "dnbd3: could not create socket\n");
+		goto error;
+	}
+
+	kernel_setsockopt(sock->sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
+	kernel_setsockopt(sock->sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
+	sock->sock->sk->sk_allocation = GFP_NOIO;
+	if (server->host.type == HOST_IP4) {
+		struct sockaddr_in sin;
+		memset(&sin, 0, sizeof(sin));
+		sin.sin_family = AF_INET;
+		memcpy(&(sin.sin_addr), server->host.addr, 4);
+		sin.sin_port = server->host.port;
+		if (kernel_connect(sock->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0) {
+			printk(KERN_ERR "dnbd3: connection to host failed (ipv4)\n");
+			goto error;
+		}
+	} else {
+		struct sockaddr_in6 sin;
+		memset(&sin, 0, sizeof(sin));
+		sin.sin6_family = AF_INET6;
+		memcpy(&(sin.sin6_addr), server->host.addr, 16);
+		sin.sin6_port = server->host.port;
+		if (kernel_connect(sock->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0){
+			printk(KERN_ERR "dnbd3: connection to host failed (ipv6)\n");
+			goto error;
+		}
+	}
+	// Request filesize
+	dnbd3_request.magic = dnbd3_packet_magic;
+	dnbd3_request.cmd = CMD_SELECT_IMAGE;
+	iov[0].iov_base = &dnbd3_request;
+	iov[0].iov_len = sizeof(dnbd3_request);
+	serializer_reset_write(&payload_buffer);
+	serializer_put_uint16(&payload_buffer, PROTOCOL_VERSION);
+	serializer_put_string(&payload_buffer, dev->imgname);
+	serializer_put_uint16(&payload_buffer, dev->rid);
+	serializer_put_uint8(&payload_buffer, 0); // is_server = false
+	iov[1].iov_base = &payload_buffer;
+	dnbd3_request.size = iov[1].iov_len = serializer_get_written_length(&payload_buffer);
+	fixup_request(dnbd3_request);
+	mlen = sizeof(dnbd3_request) + iov[1].iov_len;
+	if (kernel_sendmsg(sock->sock, &msg, iov, 2, mlen) != mlen) {
+		printk(KERN_ERR "dnbd3: could not send CMD_SIZE_REQUEST\n");
+		goto error;
+	}
+	// receive reply header
+	iov[0].iov_base = &dnbd3_reply;
+	iov[0].iov_len = sizeof(dnbd3_reply);
+	if (kernel_recvmsg(sock->sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply)) {
+		printk(KERN_ERR "dnbd3: received corrupted reply header after CMD_SIZE_REQUEST\n");
+		goto error;
+	}
+
+	// check reply header
+	fixup_reply(dnbd3_reply);
+	if (dnbd3_reply.cmd != CMD_SELECT_IMAGE ||
+			dnbd3_reply.size < 3 ||
+			dnbd3_reply.size > MAX_PAYLOAD ||
+			dnbd3_reply.magic != dnbd3_packet_magic) {
+		printk(KERN_ERR "dnbd3: received invalid reply to CMD_SIZE_REQUEST image does not exist on server\n");
+		goto error;
+	}
+
+	// receive reply payload
+	iov[0].iov_base = &payload_buffer;
+	iov[0].iov_len = dnbd3_reply.size;
+	if (kernel_recvmsg(sock->sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != dnbd3_reply.size) {
+		printk(KERN_ERR "dnbd3: could not read CMD_SELECT_IMAGE payload on handshake\n");
+		goto error;
+	}
+
+	// handle/check reply payload
+	serializer_reset_read(&payload_buffer, dnbd3_reply.size);
+	server->protocol_version = serializer_get_uint16(&payload_buffer);
+	if (server->protocol_version < MIN_SUPPORTED_SERVER) {
+		printk(KERN_ERR "dnbd3: server version is lower than min supported version\n");
+		goto error;
+	}
+
+	name = serializer_get_string(&payload_buffer);
+	rid = serializer_get_uint16(&payload_buffer);
+	if (dev->rid != rid && strcmp(name, dev->imgname) != 0) {
+		printk(KERN_ERR "dnbd3: server offers image '%s', requested '%s'\n", name, dev->imgname);
+		goto error;
+	}
+
+	reported_size = serializer_get_uint64(&payload_buffer);
+	if (dev->reported_size == NULL) {
+		if (reported_size < 4096) {
+			printk(KERN_ERR "dnbd3: reported size by server is < 4096\n");
+			goto error;
+		}
+		dev->reported_size = reported_size;
+		set_capacity(dev->disk, dev->reported_size >> 9); /* 512 Byte blocks */
+	} else if (dev->reported_size != reported_size) {
+		printk(KERN_ERR "dnbd3: reported size by server is %llu but should be %llu\n", reported_size, dev->reported_size);
+	}
+
+	printk(KERN_DEBUG "dnbd3: connected to image %s, filesize %llu\n", dev->imgname, dev->reported_size);
+
+//	TODO add heartbeat
+	// add heartbeat timer and scheduler for the command
+	INIT_WORK(&sock->keepalive, keepalive);
+	sock->heartbeat_count = 0;
+	timer_setup(&sock->keepalive_timer, dnbd3_keepalive, 0);
+	sock->keepalive_timer.expires = KEEPALIVE_TIMER;
+	add_timer(&sock->keepalive_timer);
+
+	mutex_unlock(&sock->lock);
+
+	return 0;
+error:
+	if (sock->sock) {
+		sock_release(sock->sock);
+		sock->sock = NULL;
+	}
+	if (req1) {
+		kfree(req1);
+	}
+	mutex_unlock(&sock->lock);
+	return result;
+}
+
+static int dnbd3_socket_disconnect(dnbd3_device *dev, dnbd3_sock *sock)
+{
+	printk(KERN_DEBUG "dnbd3: socket disconnect device %i\n", dev->minor);
+	mutex_lock(&sock->lock);
+
+	// clear heartbeat timer
+	del_timer_sync(&sock->keepalive_timer);
+//	destroy_workqueue(&sock->keepalive);
+
+	if (sock->sock) {
+		kernel_sock_shutdown(sock->sock, SHUT_RDWR);
+	}
+
+	// clear socket
+	if (sock->sock) {
+		sock_release(sock->sock);
+		sock->sock = NULL;
+	}
+
+	mutex_unlock(&sock->lock);
+	mutex_destroy(&sock->lock);
+	return 0;
+}
+
+int dnbd3_net_disconnect(struct dnbd3_device *dev)
+{
+	int i;
+	int result;
+	del_timer_sync(&dev->discovery_timer);
+//	destroy_workqueue(&dev->discovery);
+	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
+		if (dev->socks[i].sock) {
+			if (dnbd3_socket_disconnect(dev, &dev->socks[i])) {
+				result = -EIO;
+			}
+		}
+	}
+	return result;
+}
+
+
+int dnbd3_net_connect(struct dnbd3_device *dev) {
+	// TODO decide which socket to connect
+	int result;
+	dev->socks[0].server = &dev->initial_server;
+	if (dnbd3_socket_connect(dev, &dev->socks[0]) == 0) {
+		printServerList(dev);
+
+		INIT_WORK(&dev->discovery, discovery);
+		timer_setup(&dev->discovery_timer, dnbd3_discovery, 0);
+		dev->discovery_timer.expires = DISCOVERY_TIMER;
+		add_timer(&dev->discovery_timer);
+
+		result = 0;
+	} else {
+		printk(KERN_ERR "dnbd3: failed to connect to initial server\n");
+		result = -ENOENT;
+		dev->imgname = NULL;
+		dev->socks[0].server = NULL;
+	}
+	return result;
+}
+
+
+
diff --git a/src/kernel/net.h b/src/kernel/net.h
new file mode 100644
index 0000000..6cd0ffa
--- /dev/null
+++ b/src/kernel/net.h
@@ -0,0 +1,33 @@
+/*
+ * 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 NET_H_
+#define NET_H_
+
+
+int dnbd3_send_request(struct dnbd3_device *dev, struct dnbd3_sock *sock, struct request *req);
+
+
+int dnbd3_net_connect(struct dnbd3_device *dev);
+int dnbd3_net_disconnect(struct dnbd3_device *dev);
+
+#endif /* NET_H_ */
diff --git a/src/kernel/sysfs.c b/src/kernel/sysfs.c
index 118cbca..b5e180b 100644
--- a/src/kernel/sysfs.c
+++ b/src/kernel/sysfs.c
@@ -18,9 +18,10 @@
  *
  */
 
+#include "sysfs.h"
+
 #include <linux/kobject.h>
 
-#include "sysfs.h"
 #include "utils.h"
 
 #ifndef MIN
@@ -42,7 +43,7 @@
 //	return MIN(snprintf(buf, PAGE_SIZE, "%llu\n", (unsigned long long)dev->cur_rtt), PAGE_SIZE);
 //}
 
-ssize_t show_alt_server_num(char *buf, dnbd3_device_t *dev)
+ssize_t show_alt_server_num(char *buf, dnbd3_device *dev)
 {
 	int i, num = 0;
 	for (i = 0; i < NUMBER_SERVERS; ++i)
@@ -52,7 +53,7 @@ ssize_t show_alt_server_num(char *buf, dnbd3_device_t *dev)
 	return MIN(snprintf(buf, PAGE_SIZE, "%d\n", num), PAGE_SIZE);
 }
 
-ssize_t show_alt_servers(char *buf, dnbd3_device_t *dev)
+ssize_t show_alt_servers(char *buf, dnbd3_device *dev)
 {
 	int i, size = PAGE_SIZE, ret;
 	for (i = 0; i < NUMBER_SERVERS; ++i)
@@ -84,18 +85,18 @@ ssize_t show_alt_servers(char *buf, dnbd3_device_t *dev)
 	return PAGE_SIZE - size;
 }
 
-ssize_t show_image_name(char *buf, dnbd3_device_t *dev)
+ssize_t show_image_name(char *buf, dnbd3_device *dev)
 {
 	if (dev->imgname == NULL) return sprintf(buf, "(null)");
 	return MIN(snprintf(buf, PAGE_SIZE, "%s\n", dev->imgname), PAGE_SIZE);
 }
 
-ssize_t show_rid(char *buf, dnbd3_device_t *dev)
+ssize_t show_rid(char *buf, dnbd3_device *dev)
 {
 	return MIN(snprintf(buf, PAGE_SIZE, "%d\n", dev->rid), PAGE_SIZE);
 }
 
-ssize_t show_update_available(char *buf, dnbd3_device_t *dev)
+ssize_t show_update_available(char *buf, dnbd3_device *dev)
 {
 	return MIN(snprintf(buf, PAGE_SIZE, "%d\n", dev->update_available), PAGE_SIZE);
 }
@@ -152,7 +153,7 @@ device_attr_t update_available =
 ssize_t device_show(struct kobject *kobj, struct attribute *attr, char *buf)
 {
 	device_attr_t *device_attr = container_of(attr, device_attr_t, attr);
-	dnbd3_device_t *dev = container_of(kobj, dnbd3_device_t, kobj);
+	dnbd3_device *dev = container_of(kobj, dnbd3_device, kobj);
 	return device_attr->show(buf, dev);
 }
 
@@ -187,7 +188,7 @@ struct kobj_type device_ktype =
 };
 
 
-void dnbd3_sysfs_init(dnbd3_device_t *dev)
+void dnbd3_sysfs_init(dnbd3_device *dev)
 {
 	int error;
 	struct kobject *kobj = &dev->kobj;
@@ -199,7 +200,7 @@ void dnbd3_sysfs_init(dnbd3_device_t *dev)
 		printk("Error initializing dnbd3 device!\n");
 }
 
-void dnbd3_sysfs_exit(dnbd3_device_t *dev)
+void dnbd3_sysfs_exit(dnbd3_device *dev)
 {
 	kobject_put(&dev->kobj);
 }
diff --git a/src/kernel/sysfs.h b/src/kernel/sysfs.h
index 0a747a5..b48acc3 100644
--- a/src/kernel/sysfs.h
+++ b/src/kernel/sysfs.h
@@ -23,22 +23,22 @@
 
 #include "dnbd3.h"
 
-void dnbd3_sysfs_init(dnbd3_device_t *dev);
+void dnbd3_sysfs_init(dnbd3_device *dev);
 
-void dnbd3_sysfs_exit(dnbd3_device_t *dev);
+void dnbd3_sysfs_exit(dnbd3_device *dev);
 
 typedef struct
 {
 	struct attribute attr;
-	ssize_t (*show)(char *, dnbd3_device_t *);
-	ssize_t (*store)(const char *, size_t, dnbd3_device_t *);
+	ssize_t (*show)(char *, dnbd3_device *);
+	ssize_t (*store)(const char *, size_t, dnbd3_device *);
 } device_attr_t;
 
 typedef struct
 {
 	struct attribute attr;
-	ssize_t (*show)(char *, dnbd3_server_t *);
-	ssize_t (*store)(const char *, size_t, dnbd3_server_t *);
+	ssize_t (*show)(char *, dnbd3_server *);
+	ssize_t (*store)(const char *, size_t, dnbd3_server *);
 } server_attr_t;
 
 
diff --git a/src/kernel/utils.c b/src/kernel/utils.c
index 902025f..957d69b 100644
--- a/src/kernel/utils.c
+++ b/src/kernel/utils.c
@@ -18,9 +18,10 @@
  *
  */
 
+#include "utils.h"
+
 #include <linux/kernel.h>
 
-#include "utils.h"
 
 unsigned int inet_addr(char *str)
 {