/*
* 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"
#include "serialize.h"
#include <linux/time.h>
#ifndef MIN
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
int dnbd3_net_connect(dnbd3_device_t *dev)
{
struct sockaddr_in sin;
struct request *req1 = kmalloc(sizeof(*req1), GFP_ATOMIC);
struct timeval timeout;
timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DATA;
timeout.tv_usec = 0;
// do some checks before connecting
if (!req1)
{
printk("FATAL: Kmalloc(1) failed.\n");
goto error;
}
if (dev->cur_server.port == 0 || dev->cur_server.hostaddrtype == 0 || dev->imgname == NULL)
{
printk("FATAL: Host, port or image name not set.\n");
goto error;
}
if (dev->sock)
{
if (dev->cur_server.hostaddrtype == AF_INET)
printk("ERROR: Device %s is already connected to %pI4 : %d.\n", dev->disk->disk_name, dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
else
printk("ERROR: Device %s is already connected to %pI6 : %d.\n", dev->disk->disk_name, dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
goto error;
}
if (dev->cur_server.hostaddrtype == AF_INET)
printk("INFO: Connecting device %s to %pI4 : %d\n", dev->disk->disk_name, dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
else
{
printk("ERROR: Cannot connect to %pI6 - IPv6 not yet implemented.\n", dev->cur_server.hostaddr);
//printk("INFO: Connecting device %s to %pI6 : %d\n", dev->disk->disk_name, dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
goto error;
}
if (dev->better_sock == NULL)
{ // no established connection yet from discovery thread, start new one
dnbd3_request_t dnbd3_request;
dnbd3_reply_t dnbd3_reply;
struct msghdr msg;
struct kvec iov[2];
uint16_t rid;
char *name;
init_msghdr(msg);
if (sock_create_kern(AF_INET, SOCK_STREAM, IPPROTO_TCP, &dev->sock) < 0)
{
printk("ERROR: Couldn't create socket.\n");
goto error;
}
kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO, (char *) &timeout, sizeof(timeout));
kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO, (char *) &timeout, sizeof(timeout));
dev->sock->sk->sk_allocation = GFP_NOIO;
sin.sin_family = AF_INET;
memcpy(&(sin.sin_addr.s_addr), dev->cur_server.hostaddr, 4);
sin.sin_port = dev->cur_server.port;
if (kernel_connect(dev->sock, (struct sockaddr *) &sin, sizeof(sin), 0) != 0)
{
printk("ERROR: Couldn't connect to host %pI4 : %d\n", dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
goto error;
}
// Request filesize
dnbd3_request.magic = dnbd3_packet_magic;
dnbd3_request.cmd = CMD_GET_SIZE;
dnbd3_request.size = strlen(dev->imgname) + 1 + 2 + 2; // str+\0, version, rid
fixup_request(dnbd3_request);
iov[0].iov_base = &dnbd3_request;
iov[0].iov_len = sizeof(dnbd3_request);
serializer_reset_write(&dev->payload_buffer);
serializer_put_uint16(&dev->payload_buffer, PROTOCOL_VERSION);
serializer_put_string(&dev->payload_buffer, dev->imgname);
serializer_put_uint16(&dev->payload_buffer, dev->rid);
iov[1].iov_base = &dev->payload_buffer;
iov[1].iov_len = serializer_get_written_length(&dev->payload_buffer);
if (kernel_sendmsg(dev->sock, &msg, iov, 2, sizeof(dnbd3_request) + iov[1].iov_len) != sizeof(dnbd3_request) + iov[1].iov_len)
{
printk("ERROR: Couldn't send CMD_SIZE_REQUEST to %pI4 : %d\n", dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
goto error;
}
// receive reply header
iov[0].iov_base = &dnbd3_reply;
iov[0].iov_len = sizeof(dnbd3_reply);
if (kernel_recvmsg(dev->sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply))
{
printk("FATAL: Received corrupted reply header after CMD_SIZE_REQUEST.\n");
goto error;
}
fixup_reply(dnbd3_reply);
if (dnbd3_reply.cmd != CMD_GET_SIZE || dnbd3_reply.size < 3 || dnbd3_reply.size > MAX_PAYLOAD || dnbd3_reply.magic != dnbd3_packet_magic)
{
printk("FATAL: Received invalid reply to CMD_SIZE_REQUEST, image doesn't exist on server.\n");
goto error;
}
// receive reply payload
iov[0].iov_base = &dev->payload_buffer;
iov[0].iov_len = dnbd3_reply.size;
if (kernel_recvmsg(dev->sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != dnbd3_reply.size)
{
printk("FATAL: Cold not read CMD_GET_SIZE payload on handshake.\n");
goto error;
}
serializer_reset_read(&dev->payload_buffer, dnbd3_reply.size);
// read reply payload
dev->cur_server.protocol_version = serializer_get_uint16(&dev->payload_buffer);
if (dev->cur_server.protocol_version < MIN_SUPPORTED_SERVER)
{
printk("FATAL: Server version is lower than min supported version.\n");
goto error;
}
name = serializer_get_string(&dev->payload_buffer);
if (dev->rid != 0 && strcmp(name, dev->imgname) != 0)
{
printk("FATAL: Server provides different image than asked for.\n");
goto error;
}
if (strlen(dev->imgname) < strlen(name))
{
dev->imgname = krealloc(dev->imgname, strlen(name) + 1, GFP_ATOMIC);
if (dev->imgname == NULL)
{
printk("FATAL: Reallocating buffer for new image name failed");
goto error;
}
}
strcpy(dev->imgname, name);
rid = serializer_get_uint16(&dev->payload_buffer);
if (dev->rid != 0 && dev->rid != rid)
{
printk("FATAL: Server provides different rid of image than asked for.\n");
goto error;
}
dev->rid = rid;
dev->reported_size = serializer_get_uint64(&dev->payload_buffer);
// store image information
set_capacity(dev->disk, dev->reported_size >> 9); /* 512 Byte blocks */
printk("INFO: Filesize of %s: %llu\n", dev->disk->disk_name, dev->reported_size);
}
else // Switching server, connection is already established and size request was executed
{
printk("INFO: On-the-fly server change\n");
dev->sock = dev->better_sock;
dev->better_sock = NULL;
kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO, (char *) &timeout, sizeof(timeout));
kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO, (char *) &timeout, sizeof(timeout));
}
dev->panic = 0;
dev->panic_count = 0;
dev->alt_servers_num = 0;
dev->update_available = 0;
// enqueue request to request_queue_send (ask alt servers)
req1->cmd_type = REQ_TYPE_SPECIAL;
req1->cmd_flags = CMD_GET_SERVERS;
list_add(&req1->queuelist, &dev->request_queue_send);
// create required threads
dev->thread_send = kthread_create(dnbd3_net_send, dev, dev->disk->disk_name);
dev->thread_receive = kthread_create(dnbd3_net_receive, dev, dev->disk->disk_name);
dev->thread_discover = kthread_create(dnbd3_net_discover, dev, dev->disk->disk_name);
// start them up
wake_up_process(dev->thread_send);
wake_up_process(dev->thread_receive);
wake_up_process(dev->thread_discover);
wake_up(&dev->process_queue_send);
// 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 + TIMER_INTERVAL_HEARTBEAT;
add_timer(&dev->hb_timer);
return 0;
error:
if (dev->sock)
{
sock_release(dev->sock);
dev->sock = NULL;
}
dev->cur_server.hostaddrtype = 0;
dev->cur_server.port = 0;
if (req1) kfree(req1);
return -1;
}
int dnbd3_net_disconnect(dnbd3_device_t *dev)
{
printk("INFO: Disconnecting device %s\n", dev->disk->disk_name);
dev->disconnecting = 1;
// clear heartbeat timer
if (&dev->hb_timer)
del_timer(&dev->hb_timer);
dev->discover = 0;
if (dev->sock)
kernel_sock_shutdown(dev->sock, SHUT_RDWR);
// kill sending and receiving threads
if (dev->thread_send)
{
kthread_stop(dev->thread_send);
dev->thread_send = NULL;
}
if (dev->thread_receive)
{
kthread_stop(dev->thread_receive);
dev->thread_receive = NULL;
}
if (dev->thread_discover)
{
kthread_stop(dev->thread_discover);
dev->thread_discover = NULL;
}
// clear socket
if (dev->sock)
{
sock_release(dev->sock);
dev->sock = NULL;
}
dev->cur_server.hostaddrtype = 0;
dev->cur_server.port = 0;
dev->disconnecting = 0;
return 0;
}
void dnbd3_net_heartbeat(unsigned long arg)
{
dnbd3_device_t *dev = (dnbd3_device_t *) arg;
if (!dev->panic)
{
struct request *req = kmalloc(sizeof(struct request), GFP_ATOMIC);
// send keepalive
if (req)
{
req->cmd_type = REQ_TYPE_SPECIAL;
req->cmd_flags = CMD_GET_SERVERS;
list_add_tail(&req->queuelist, &dev->request_queue_send);
wake_up(&dev->process_queue_send);
}
else
{
printk("ERROR: Couldn't create keepalive request\n");
}
}
// start discover
dev->discover = 1;
wake_up(&dev->process_queue_discover);
if (dev->panic)
dev->hb_timer.expires = jiffies + TIMER_INTERVAL_PANIC;
else
dev->hb_timer.expires = jiffies + TIMER_INTERVAL_HEARTBEAT;
add_timer(&dev->hb_timer);
}
int dnbd3_net_discover(void *data)
{
dnbd3_device_t *dev = data;
struct sockaddr_in sin;
struct socket *sock, *best_sock = NULL;
dnbd3_request_t dnbd3_request;
dnbd3_reply_t dnbd3_reply;
struct msghdr msg;
struct kvec iov[2];
char *buf, *name;
serialized_buffer_t *payload;
uint64_t filesize;
uint16_t rid;
struct timeval start, end;
uint64_t rtt, best_rtt = 0;
int i, best_server, current_server;
int turn = 0;
int ready = 0;
struct timeval timeout;
timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DISCOVERY;
timeout.tv_usec = 0;
init_msghdr(msg);
buf = kmalloc(4096, GFP_KERNEL);
if (!buf)
{
printk("FATAL: Kmalloc failed (discover)\n");
return -1;
}
payload = (serialized_buffer_t*)buf;
dnbd3_request.magic = dnbd3_packet_magic;
for (;;)
{
wait_event_interruptible(dev->process_queue_discover,
kthread_should_stop() || dev->discover);
if (kthread_should_stop() || dev->imgname == NULL)
break;
if (!dev->discover)
continue;
dev->discover = 0;
// Check if the list of alt servers needs to be updated and do so if neccessary
spin_lock_irq(&dev->blk_lock);
if (dev->new_servers_num)
{
for (i = 0; i < dev->new_servers_num; ++i)
{
memcpy(dev->alt_servers[i].hostaddr, dev->new_servers[i].ipaddr, 16);
dev->alt_servers[i].hostaddrtype = dev->new_servers[i].addrtype;
dev->alt_servers[i].port = dev->new_servers[i].port;
memset(dev->alt_servers[i].rtts, 0xFF, sizeof(dev->alt_servers[i].rtts[0]) * 4);
dev->alt_servers[i].protocol_version = 0;
dev->alt_servers[i].skip_count = 0;
}
dev->alt_servers_num = dev->new_servers_num;
dev->new_servers_num = 0;
}
spin_unlock_irq(&dev->blk_lock);
current_server = best_server = -1;
best_rtt = 0xFFFFFFFFFFFFull;
for (i=0; i < dev->alt_servers_num; ++i)
{
if (dev->alt_servers[i].hostaddrtype != AF_INET) // add IPv6....
continue;
if (!dev->panic && dev->alt_servers[i].skip_count) // If not in panic mode, skip server if indicated
{
--dev->alt_servers[i].skip_count;
continue;
}
// Initialize socket and connect
if (sock_create_kern(AF_INET, SOCK_STREAM, IPPROTO_TCP, &sock) < 0)
{
printk("ERROR: Couldn't create socket (discover)\n");
sock = NULL;
continue;
}
kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char *) &timeout, sizeof(timeout));
kernel_setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char *) &timeout, sizeof(timeout));
sock->sk->sk_allocation = GFP_NOIO;
sin.sin_family = AF_INET; // add IPv6.....
memcpy(&sin.sin_addr.s_addr, dev->alt_servers[i].hostaddr, 4);
sin.sin_port = dev->alt_servers[i].port;
if (kernel_connect(sock, (struct sockaddr *) &sin, sizeof(sin), 0) < 0)
{
//printk("ERROR: Couldn't connect to host %s:%s (discover)\n", current_server, dev->cur_server.port);
goto error;
}
// Request filesize
dnbd3_request.cmd = CMD_GET_SIZE;
fixup_request(dnbd3_request);
iov[0].iov_base = &dnbd3_request;
iov[0].iov_len = sizeof(dnbd3_request);
serializer_reset_write(payload);
serializer_put_uint16(payload, PROTOCOL_VERSION);
serializer_put_string(payload, dev->imgname);
serializer_put_uint16(payload, dev->rid);
iov[1].iov_base = payload;
dnbd3_request.size = iov[1].iov_len = serializer_get_written_length(payload);
if (kernel_sendmsg(sock, &msg, iov, 2, sizeof(dnbd3_request) + iov[1].iov_len) != sizeof(dnbd3_request) + iov[1].iov_len)
{
printk("ERROR: Requesting image size failed (%pI4 : %d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
// receive net reply
iov[0].iov_base = &dnbd3_reply;
iov[0].iov_len = sizeof(dnbd3_reply);
if (kernel_recvmsg(sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply))
{
printk("ERROR: Receiving image size packet (header) failed (%pI4 :%d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
fixup_reply(dnbd3_reply);
if (dnbd3_reply.magic != dnbd3_packet_magic || dnbd3_reply.cmd != CMD_GET_SIZE || dnbd3_reply.size < 4)
{
printk("ERROR: Content of image size packet (header) mismatched (%pI4 :%d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
// receive data
iov[0].iov_base = payload;
iov[0].iov_len = dnbd3_reply.size;
if (kernel_recvmsg(sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != dnbd3_reply.size)
{
printk("ERROR: Receiving image size packet (payload) failed (%pI4 : %d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
serializer_reset_read(payload, dnbd3_reply.size);
dev->alt_servers[i].protocol_version = serializer_get_uint16(payload);
if (dev->alt_servers[i].protocol_version < MIN_SUPPORTED_SERVER)
{
printk("ERROR: Server version too old (client: %d, server: %d, min supported: %d) (%pI4 : %d, discover)\n", (int)PROTOCOL_VERSION, (int)dev->alt_servers[i].protocol_version, (int)MIN_SUPPORTED_SERVER, dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
name = serializer_get_string(payload);
if (name == NULL)
{
printk("ERROR: Server did not supply an image name (%pI4 : %d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
if (strcmp(name, dev->imgname) != 0)
{
printk("ERROR: Image name does not match requested one (client: '%s', server: '%s') (%pI4 : %d, discover)\n", dev->imgname, name, dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
rid = serializer_get_uint16(payload);
if (rid != dev->rid)
{
printk("ERROR: Server supplied wrong rid (client: '%d', server: '%d') (%pI4 : %d, discover)\n", (int)dev->rid, (int)rid, dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
filesize = serializer_get_uint64(payload);
if (filesize != dev->reported_size)
{
printk("ERROR: Reported image size of %llu does not match expected value %llu. (%pI4 :%d, discover)\n", (unsigned long long)filesize, (unsigned long long)dev->reported_size, dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
// panic mode, take first responding server
if (dev->panic)
{
printk("WARN: Panic mode (%s), taking server %pI4 : %d\n", dev->disk->disk_name, dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
if (best_sock != NULL) sock_release(best_sock);
dev->better_sock = sock; // Pass over socket to take a shortcut in *_connect();
kfree(buf);
dev->thread_discover = NULL;
dnbd3_net_disconnect(dev);
memcpy(&dev->cur_server, &dev->alt_servers[i], sizeof(dev->cur_server));
dnbd3_net_connect(dev);
return 0;
}
// start rtt measurement
do_gettimeofday(&start);
// Request block
dnbd3_request.cmd = CMD_GET_BLOCK;
dnbd3_request.offset = ((start.tv_usec ^ start.tv_sec) % dev->reported_size) & ~(uint64_t)(RTT_BLOCK_SIZE-1); // Pick random block
dnbd3_request.size = RTT_BLOCK_SIZE;
fixup_request(dnbd3_request);
iov[0].iov_base = &dnbd3_request;
iov[0].iov_len = sizeof(dnbd3_request);
if (kernel_sendmsg(sock, &msg, iov, 1, sizeof(dnbd3_request)) <= 0)
{
printk("ERROR: Requesting test block failed (%pI4 : %d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
// receive net reply
iov[0].iov_base = &dnbd3_reply;
iov[0].iov_len = sizeof(dnbd3_reply);
if (kernel_recvmsg(sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply))
{
printk("ERROR: Receiving test block header packet failed (%pI4 : %d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
fixup_reply(dnbd3_reply);
if (dnbd3_reply.cmd != CMD_GET_BLOCK || dnbd3_reply.size != RTT_BLOCK_SIZE)
{
printk("ERROR: Unexpected reply to block request: cmd=%d, size=%d (%pI4 : %d, discover)\n", (int)dnbd3_reply.cmd, (int)dnbd3_reply.size, dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
// receive data
iov[0].iov_base = buf;
iov[0].iov_len = RTT_BLOCK_SIZE;
if (kernel_recvmsg(sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != RTT_BLOCK_SIZE)
{
printk("ERROR: Receiving test block payload failed (%pI4 : %d, discover)\n", dev->alt_servers[i].hostaddr, (int)ntohs(dev->alt_servers[i].port));
goto error;
}
do_gettimeofday(&end); // end rtt measurement
dev->alt_servers[i].rtts[turn] =
(end.tv_sec - start.tv_sec) * 1000000ull
+ (end.tv_usec - start.tv_usec);
rtt = ( dev->alt_servers[i].rtts[0]
+ dev->alt_servers[i].rtts[1]
+ dev->alt_servers[i].rtts[2]
+ dev->alt_servers[i].rtts[3] ) / 4;
if (best_rtt > rtt)
{ // This one is better, keep socket open in case we switch
best_rtt = rtt;
best_server = i;
if (best_sock != NULL) sock_release(best_sock);
best_sock = sock;
sock = NULL;
}
else
{ // Not better, discard connection
sock_release(sock);
sock = NULL;
}
// update cur servers rtt
if (dev->cur_server.port == dev->alt_servers[i].port && dev->cur_server.hostaddrtype == dev->alt_servers[i].hostaddrtype
&& (
(dev->cur_server.hostaddrtype == AF_INET
&& memcmp(dev->cur_server.hostaddr, dev->alt_servers[i].hostaddr, 4) == 0)
||
(dev->cur_server.hostaddrtype == AF_INET6
&& memcmp(dev->cur_server.hostaddr, dev->alt_servers[i].hostaddr, 16) == 0)
)
)
{
dev->cur_rtt = rtt;
current_server = i;
}
continue;
error:
sock_release(sock);
sock = NULL;
dev->alt_servers[i].rtts[turn] = 0xFFFFFFFF;
continue;
}
if (dev->panic && ++dev->panic_count == 21)
{ // After 21 retries, bail out by reporting errors to block layer
dnbd3_blk_fail_all_requests(dev);
}
if (best_server == -1 || kthread_should_stop()) // No alt server could be reached at all or thread should stop
{
if (best_sock != NULL) // Should never happen actually
{
sock_release(best_sock);
best_sock = NULL;
}
continue;
}
// take server with lowest rtt
if (ready && best_server != current_server
&& dev->cur_rtt > best_rtt + RTT_THRESHOLD)
{
printk("INFO: Server %d on %s is faster (%lluµs)\n", best_server, dev->disk->disk_name, best_rtt);
kfree(buf);
dev->better_sock = best_sock; // Take shortcut by continuing to use open connection
dev->thread_discover = NULL;
dnbd3_net_disconnect(dev);
memcpy(&dev->cur_server, &dev->alt_servers[best_server], sizeof(dev->cur_server));
dev->cur_rtt = best_rtt;
dnbd3_net_connect(dev);
return 0;
}
// Clean up connection that was held open for quicker server switch
if (best_sock != NULL)
{
sock_release(best_sock);
best_sock = NULL;
}
turn = (turn + 1) % 4;
if (turn == 3)
ready = 1;
}
kfree(buf);
return 0;
}
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);
dnbd3_request.magic = dnbd3_packet_magic;
set_user_nice(current, -20);
for (;;)
{
wait_event_interruptible(dev->process_queue_send,
kthread_should_stop() || !list_empty(&dev->request_queue_send));
if (kthread_should_stop())
break;
// extract block request
spin_lock_irq(&dev->blk_lock); // TODO: http://www.linuxjournal.com/article/5833 says spin_lock_irq should not be used in general, but article is 10 years old
if (list_empty(&dev->request_queue_send))
{
spin_unlock_irq(&dev->blk_lock);
continue;
}
blk_request = list_entry(dev->request_queue_send.next, struct 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
// enqueue request to request_queue_receive
spin_lock_irq(&dev->blk_lock);
list_del_init(&blk_request->queuelist);
list_add_tail(&blk_request->queuelist, &dev->request_queue_receive);
spin_unlock_irq(&dev->blk_lock);
break;
case REQ_TYPE_SPECIAL:
dnbd3_request.cmd = blk_request->cmd_flags;
dnbd3_request.size = 0;
spin_lock_irq(&dev->blk_lock);
list_del_init(&blk_request->queuelist);
spin_unlock_irq(&dev->blk_lock);
break;
default:
printk("ERROR: Unknown command (send)\n");
spin_lock_irq(&dev->blk_lock);
list_del_init(&blk_request->queuelist);
spin_unlock_irq(&dev->blk_lock);
continue;
}
// send net request
dnbd3_request.handle = (uint64_t)(uintptr_t)blk_request; // 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(dev->sock, &msg, &iov, 1, sizeof(dnbd3_request)) != sizeof(dnbd3_request))
{
printk("Couldn't properly send a request header.\n");
goto error;
}
wake_up(&dev->process_queue_receive);
}
return 0;
error:
printk("ERROR: Connection to server %pI4 : %d lost (send)\n", dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
if (dev->sock)
kernel_sock_shutdown(dev->sock, SHUT_RDWR);
dev->thread_send = NULL;
if (!dev->disconnecting)
{
dev->panic = 1;
// start discover
dev->discover = 1;
wake_up(&dev->process_queue_discover);
}
return -1;
}
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;
int count, remaining, ret;
init_msghdr(msg);
set_user_nice(current, -20);
while (!kthread_should_stop())
{
// receive net reply
iov.iov_base = &dnbd3_reply;
iov.iov_len = sizeof(dnbd3_reply);
ret = kernel_recvmsg(dev->sock, &msg, &iov, 1, sizeof(dnbd3_reply), msg.msg_flags);
if (ret == -EAGAIN)
{
msleep_interruptible(2000); // Sleep at most 2 seconds, then check if we can receive something
// If a request for a block was sent, the thread is waken up immediately, so that we don't wait 2 seconds for the reply
// This change was made to allow unrequested information from the server to be received (push)
continue;
}
if (ret <= 0)
{
printk("Connection closed (%d).\n", ret);
goto error;
}
if (ret != sizeof(dnbd3_reply))
{
printk("ERROR: Recv msg header\n");
goto error;
}
fixup_reply(dnbd3_reply);
// check error
if (dnbd3_reply.magic != dnbd3_packet_magic)
{
printk("ERROR: Wrong packet magic (Receive)\n");
goto error;
}
if (dnbd3_reply.cmd == 0)
{
printk("ERROR: Command was 0 (Receive)\n");
goto error;
}
// what to do?
switch (dnbd3_reply.cmd)
{
case CMD_GET_BLOCK:
// search for replied request in queue
blk_request = NULL;
spin_lock_irq(&dev->blk_lock);
list_for_each_entry_safe(received_request, tmp_request, &dev->request_queue_receive, queuelist)
{
if ((uint64_t)(uintptr_t)received_request == dnbd3_reply.handle) // Double cast to prevent warning on 32bit
{
blk_request = received_request;
break;
}
}
spin_unlock_irq(&dev->blk_lock);
if (blk_request == NULL)
{
printk("ERROR: Received block data for unrequested handle (%llu: %llu).\n",
(unsigned long long)dnbd3_reply.handle, (unsigned long long)dnbd3_reply.size);
goto error;
}
// 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;
iov.iov_base = kaddr;
iov.iov_len = bvec->bv_len;
if (kernel_recvmsg(dev->sock, &msg, &iov, 1, bvec->bv_len, msg.msg_flags) != bvec->bv_len)
{
printk("ERROR: Receiving from net to block layer\n");
kunmap(bvec->bv_page);
goto error;
}
kunmap(bvec->bv_page);
sigprocmask(SIG_SETMASK, &oldset, NULL);
}
spin_lock_irqsave(&dev->blk_lock, flags);
list_del_init(&blk_request->queuelist);
__blk_end_request_all(blk_request, 0);
spin_unlock_irqrestore(&dev->blk_lock, flags);
continue;
case CMD_GET_SERVERS:
spin_lock_irq(&dev->blk_lock);
dev->new_servers_num = 0;
spin_unlock_irq(&dev->blk_lock);
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(dev->sock, &msg, &iov, 1, (count * sizeof(dnbd3_server_entry_t)), msg.msg_flags) != (count * sizeof(dnbd3_server_entry_t)))
{
printk("ERROR: Recv CMD_GET_SERVERS payload.\n");
goto error;
}
spin_lock_irq(&dev->blk_lock);
dev->new_servers_num = count;
spin_unlock_irq(&dev->blk_lock);
// TODO: Re-Add update check
}
// 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));
while (remaining > 0)
{
count = MIN(sizeof(dnbd3_reply), remaining);
iov.iov_base = &dnbd3_reply;
iov.iov_len = count;
ret = kernel_recvmsg(dev->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags);
if (ret <= 0)
{
printk("ERROR: Recv additional payload from CMD_GET_SERVERS.\n");
goto error;
}
remaining -= ret;
}
continue;
default:
printk("ERROR: Unknown command (Receive)\n");
continue;
}
}
printk("dnbd3_net_receive terminated normally.\n");
return 0;
error:
printk("ERROR: Connection to server %pI4 : %d lost (receive)\n", dev->cur_server.hostaddr, (int)ntohs(dev->cur_server.port));
// move already send requests to request_queue_send again
while (!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(&blk_request->queuelist, &dev->request_queue_send);
}
spin_unlock_irq(&dev->blk_lock);
}
if (dev->sock)
kernel_sock_shutdown(dev->sock, SHUT_RDWR);
dev->thread_receive = NULL;
if (!dev->disconnecting)
{
dev->panic = 1;
// start discover
dev->discover = 1;
wake_up(&dev->process_queue_discover);
}
return -1;
}