/*
* 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 "clientconfig.h"
#include "net.h"
#include "blk.h"
#include "utils.h"
#include "serialize.h"
#include <linux/time.h>
#include <linux/signal.h>
#ifndef MIN
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
#define dnbd3_sock_create(af,type,proto,sock) sock_create_kern(&init_net, (af) == HOST_IP4 ? AF_INET : AF_INET6, type, proto, sock)
#else
#define dnbd3_sock_create(af,type,proto,sock) sock_create_kern((af) == HOST_IP4 ? AF_INET : AF_INET6, type, proto, sock)
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
// cmd_flags and cmd_type are merged into cmd_flags now
#if REQ_FLAG_BITS > 24
#error "Fix CMD bitshift"
#endif
// Pack into cmd_flags field by shifting CMD_* into unused bits of cmd_flags
#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_DEV_READ REQ_OP_READ
#define DNBD3_REQ_OP_SPECIAL REQ_OP_DRV_IN
#else
// Old way with type and flags separated
#define dnbd3_cmd_to_priv(req, cmd) do { \
(req)->cmd_type = REQ_TYPE_SPECIAL; \
(req)->cmd_flags = (cmd); \
} while (0)
#define dnbd3_priv_to_cmd(req) (req)->cmd_flags
#define dnbd3_req_op(req) (req)->cmd_type
#define DNBD3_DEV_READ REQ_TYPE_FS
#define DNBD3_REQ_OP_SPECIAL REQ_TYPE_SPECIAL
#endif
/**
* Some macros for easier debug output. Location in source-code
* as well as server IP:port info will be printed.
* The error_* macros include a "goto error;" at the end
*/
#if 1 // Change to 0 to disable debug messages
#define debug_print_va_host(_host, _fmt, ...) do { \
if ((_host).type == HOST_IP4) \
printk("%s:%d " _fmt " (%s, %pI4:%d)\n", __FILE__, __LINE__, __VA_ARGS__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \
else \
printk("%s:%d " _fmt " (%s, [%pI6]:%d)\n", __FILE__, __LINE__, __VA_ARGS__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \
} while(0)
#define debug_error_va_host(_host, _fmt, ...) do { \
debug_print_va_host(_host, _fmt, __VA_ARGS__); \
goto error; \
} while(0)
#define debug_dev_va(_fmt, ...) debug_print_va_host(dev->cur_server.host, _fmt, __VA_ARGS__)
#define error_dev_va(_fmt, ...) debug_error_va_host(dev->cur_server.host, _fmt, __VA_ARGS__)
#define debug_alt_va(_fmt, ...) debug_print_va_host(dev->alt_servers[i].host, _fmt, __VA_ARGS__)
#define error_alt_va(_fmt, ...) debug_error_va_host(dev->alt_servers[i].host, _fmt, __VA_ARGS__)
#define debug_print_host(_host, txt) do { \
if ((_host).type == HOST_IP4) \
printk("%s:%d " txt " (%s, %pI4:%d)\n", __FILE__, __LINE__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \
else \
printk("%s:%d " txt " (%s, [%pI6]:%d)\n", __FILE__, __LINE__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \
} while(0)
#define debug_error_host(_host, txt) do { \
debug_print_host(_host, txt); \
goto error; \
} while(0)
#define debug_dev(txt) debug_print_host(dev->cur_server.host, txt)
#define error_dev(txt) debug_error_host(dev->cur_server.host, txt)
#define debug_alt(txt) debug_print_host(dev->alt_servers[i].host, txt)
#define error_alt(txt) debug_error_host(dev->alt_servers[i].host, txt)
#else // Silent
#define debug_dev(x) do { } while(0)
#define error_dev(x) goto error
#define debug_dev_va(x, ...) do { } while(0)
#define error_dev_va(x, ...) goto error
#define debug_alt(x) do { } while(0)
#define error_alt(x) goto error
#define debug_alt_va(x, ...) do { } while(0)
#define error_alt_va(x, ...) goto error
#endif
static inline int is_same_server(const dnbd3_server_t * const a, const dnbd3_server_t * const b)
{
return (a->host.type == b->host.type) && (a->host.port == b->host.port)
&& (0 == memcmp(a->host.addr, b->host.addr, (a->host.type == HOST_IP4 ? 4 : 16)));
}
static inline dnbd3_server_t *get_existing_server(const dnbd3_server_entry_t * const newserver,
dnbd3_device_t * const dev)
{
int i;
for (i = 0; i < NUMBER_SERVERS; ++i)
{
if ((newserver->host.type == dev->alt_servers[i].host.type)
&& (newserver->host.port == dev->alt_servers[i].host.port)
&& (0
== memcmp(newserver->host.addr, dev->alt_servers[i].host.addr, (newserver->host.type == HOST_IP4 ? 4 : 16))))
{
return &dev->alt_servers[i];
break;
}
}
return NULL ;
}
static inline dnbd3_server_t *get_free_alt_server(dnbd3_device_t * const dev)
{
int i;
for (i = 0; i < NUMBER_SERVERS; ++i)
{
if (dev->alt_servers[i].host.type == 0)
return &dev->alt_servers[i];
}
for (i = 0; i < NUMBER_SERVERS; ++i)
{
if (dev->alt_servers[i].failures > 10)
return &dev->alt_servers[i];
}
return NULL ;
}
int dnbd3_net_connect(dnbd3_device_t *dev)
{
struct request *req1 = NULL;
struct timeval timeout;
if (dev->disconnecting) {
debug_dev("CONNECT: Still disconnecting!!!\n");
while (dev->disconnecting)
schedule();
}
if (dev->thread_receive != NULL) {
debug_dev("CONNECT: Still receiving!!!\n");
while (dev->thread_receive != NULL)
schedule();
}
if (dev->thread_send != NULL) {
debug_dev("CONNECT: Still sending!!!\n");
while (dev->thread_send != NULL)
schedule();
}
timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DATA;
timeout.tv_usec = 0;
// do some checks before connecting
req1 = kmalloc(sizeof(*req1), GFP_ATOMIC );
if (!req1)
error_dev("FATAL: Kmalloc(1) failed.");
if (dev->cur_server.host.port == 0 || dev->cur_server.host.type == 0 || dev->imgname == NULL )
error_dev("FATAL: Host, port or image name not set.");
if (dev->sock)
error_dev("ERROR: Already connected.");
if (dev->cur_server.host.type != HOST_IP4 && dev->cur_server.host.type != HOST_IP6)
error_dev_va("ERROR: Unknown address type %d", (int)dev->cur_server.host.type);
debug_dev("INFO: Connecting...");
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;
int mlen;
init_msghdr(msg);
if (dnbd3_sock_create(dev->cur_server.host.type, SOCK_STREAM, IPPROTO_TCP, &dev->sock) < 0)
error_dev("ERROR: Couldn't create socket (v6).");
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;
if (dev->cur_server.host.type == HOST_IP4)
{
struct sockaddr_in sin;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
memcpy(&(sin.sin_addr), dev->cur_server.host.addr, 4);
sin.sin_port = dev->cur_server.host.port;
if (kernel_connect(dev->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0)
error_dev("FATAL: Connection to host failed. (v4)");
}
else
{
struct sockaddr_in6 sin;
memset(&sin, 0, sizeof(sin));
sin.sin6_family = AF_INET6;
memcpy(&(sin.sin6_addr), dev->cur_server.host.addr, 16);
sin.sin6_port = dev->cur_server.host.port;
if (kernel_connect(dev->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0)
error_dev("FATAL: Connection to host failed. (v6)");
}
// 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(&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);
serializer_put_uint8(&dev->payload_buffer, 0); // is_server = false
iov[1].iov_base = &dev->payload_buffer;
dnbd3_request.size = iov[1].iov_len = serializer_get_written_length(&dev->payload_buffer);
fixup_request(dnbd3_request);
mlen = sizeof(dnbd3_request) + iov[1].iov_len;
if (kernel_sendmsg(dev->sock, &msg, iov, 2, mlen) != mlen)
error_dev("ERROR: Couldn't send CMD_SIZE_REQUEST.");
// 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))
error_dev("FATAL: Received corrupted reply header after CMD_SIZE_REQUEST.");
// 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)
error_dev("FATAL: Received invalid reply to CMD_SIZE_REQUEST, image doesn't exist on server.");
// 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)
error_dev("FATAL: Cold not read CMD_SELECT_IMAGE payload on handshake.");
// handle/check reply payload
serializer_reset_read(&dev->payload_buffer, dnbd3_reply.size);
dev->cur_server.protocol_version = serializer_get_uint16(&dev->payload_buffer);
if (dev->cur_server.protocol_version < MIN_SUPPORTED_SERVER)
error_dev("FATAL: Server version is lower than min supported version.");
name = serializer_get_string(&dev->payload_buffer);
if (dev->rid != 0 && strcmp(name, dev->imgname) != 0)
error_dev_va("FATAL: Server offers image '%s', requested '%s'", name, dev->imgname);
if (strlen(dev->imgname) < strlen(name))
{
dev->imgname = krealloc(dev->imgname, strlen(name) + 1, GFP_ATOMIC );
if (dev->imgname == NULL )
error_dev("FATAL: Reallocating buffer for new image name failed");
}
strcpy(dev->imgname, name);
rid = serializer_get_uint16(&dev->payload_buffer);
if (dev->rid != 0 && dev->rid != rid)
error_dev_va("FATAL: Server provides rid %d, requested was %d.", (int)rid, (int)dev->rid);
dev->rid = rid;
dev->reported_size = serializer_get_uint64(&dev->payload_buffer);
if (dev->reported_size < 4096)
error_dev("ERROR: Reported size by server is < 4096");
// store image information
set_capacity(dev->disk, dev->reported_size >> 9); /* 512 Byte blocks */
debug_dev_va("INFO: Filesize: %llu.", dev->reported_size);
dev->update_available = 0;
}
else // Switching server, connection is already established and size request was executed
{
debug_dev("INFO: On-the-fly server change.");
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;
// Enqueue request to request_queue_send for a fresh list of alt servers
dnbd3_cmd_to_priv(req1, 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
dev->heartbeat_count = 0;
// init_timer_key changed from kernel version 4.14 to 4.15, see and compare to 4.15:
// https://elixir.bootlin.com/linux/v4.14.32/source/include/linux/timer.h#L98
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
timer_setup(&dev->hb_timer, dnbd3_net_heartbeat, 0);
#else
// Old timer setup
init_timer(&dev->hb_timer);
dev->hb_timer.data = (unsigned long)dev;
dev->hb_timer.function = dnbd3_net_heartbeat;
#endif
dev->hb_timer.expires = jiffies + HZ;
add_timer(&dev->hb_timer);
return 0;
error: ;
if (dev->sock)
{
sock_release(dev->sock);
dev->sock = NULL;
}
dev->cur_server.host.type = 0;
dev->cur_server.host.port = 0;
if (req1)
kfree(req1);
return -1;
}
int dnbd3_net_disconnect(dnbd3_device_t *dev)
{
if (dev->disconnecting)
return 0;
if (dev->cur_server.host.port)
debug_dev("INFO: Disconnecting device.");
dev->disconnecting = 1;
// clear heartbeat 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);
}
if (dev->thread_receive)
{
kthread_stop(dev->thread_receive);
}
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.host.type = 0;
dev->cur_server.host.port = 0;
dev->disconnecting = 0;
return 0;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)
void dnbd3_net_heartbeat(struct timer_list *arg)
{
dnbd3_device_t *dev = (dnbd3_device_t *)container_of(arg, dnbd3_device_t, hb_timer);
#else
void dnbd3_net_heartbeat(unsigned long arg)
{
dnbd3_device_t *dev = (dnbd3_device_t *)arg;
#endif
// Because different events need different intervals, the timer is called once a second.
// Other intervals can be derived using dev->heartbeat_count.
#define timeout_seconds(x) (dev->heartbeat_count % (x) == 0)
if (!dev->panic)
{
if (timeout_seconds(TIMER_INTERVAL_KEEPALIVE_PACKET))
{
struct request *req = kmalloc(sizeof(struct request), GFP_ATOMIC );
// send keepalive
if (req)
{
dnbd3_cmd_to_priv(req, CMD_KEEPALIVE);
list_add_tail(&req->queuelist, &dev->request_queue_send);
wake_up(&dev->process_queue_send);
}
else
{
debug_dev("ERROR: Couldn't create keepalive request.");
}
}
if ((dev->heartbeat_count > STARTUP_MODE_DURATION && timeout_seconds(TIMER_INTERVAL_PROBE_NORMAL))
|| (dev->heartbeat_count <= STARTUP_MODE_DURATION && timeout_seconds(TIMER_INTERVAL_PROBE_STARTUP)))
{
// Normal discovery
dev->discover = 1;
wake_up(&dev->process_queue_discover);
}
}
else if (timeout_seconds(TIMER_INTERVAL_PROBE_PANIC))
{
// Panic discovery
dev->discover = 1;
wake_up(&dev->process_queue_discover);
}
dev->hb_timer.expires = jiffies + HZ;
++dev->heartbeat_count;
add_timer(&dev->hb_timer);
#undef timeout_seconds
}
int dnbd3_net_discover(void *data)
{
dnbd3_device_t *dev = data;
struct sockaddr_in sin4;
struct sockaddr_in6 sin6;
struct socket *sock, *best_sock = NULL;
dnbd3_request_t dnbd3_request;
dnbd3_reply_t dnbd3_reply;
dnbd3_server_t *alt_server;
struct msghdr msg;
struct kvec iov[2];
char *buf, *name;
serialized_buffer_t *payload;
uint64_t filesize;
uint16_t rid;
struct timeval start, end;
unsigned long rtt, best_rtt = 0;
unsigned long irqflags;
int i, j, isize, best_server, current_server;
int turn = 0;
int ready = 0, do_change = 0;
char check_order[NUMBER_SERVERS];
int mlen;
struct request *last_request = (struct request *)123, *cur_request = (struct request *)456;
struct timeval timeout;
timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DISCOVERY;
timeout.tv_usec = 0;
memset(&sin4, 0, sizeof(sin4));
memset(&sin6, 0, sizeof(sin6));
init_msghdr(msg);
buf = kmalloc(4096, GFP_KERNEL);
if (!buf)
{
debug_dev("FATAL: Kmalloc failed (discover)");
return -1;
}
payload = (serialized_buffer_t *)buf; // Reuse this buffer to save kernel mem
dnbd3_request.magic = dnbd3_packet_magic;
for (i = 0; i < NUMBER_SERVERS; ++i) {
check_order[i] = i;
}
for (;;)
{
wait_event_interruptible(dev->process_queue_discover,
kthread_should_stop() || dev->discover || dev->thread_discover == NULL);
if (kthread_should_stop() || dev->imgname == NULL || dev->thread_discover == NULL )
break;
if (!dev->discover)
continue;
dev->discover = 0;
if (dev->reported_size < 4096)
continue;
// Check if the list of alt servers needs to be updated and do so if necessary
if (dev->new_servers_num)
{
spin_lock_irqsave(&dev->blk_lock, irqflags);
for (i = 0; i < dev->new_servers_num; ++i)
{
if (dev->new_servers[i].host.type != HOST_IP4 && dev->new_servers[i].host.type != HOST_IP6) // Invalid entry?
continue;
alt_server = get_existing_server(&dev->new_servers[i], dev);
if (alt_server != NULL ) // Server already known
{
if (dev->new_servers[i].failures == 1)
{
// REMOVE request
if (alt_server->host.type == HOST_IP4)
debug_dev_va("Removing alt server %pI4", alt_server->host.addr);
else
debug_dev_va("Removing alt server %pI6", alt_server->host.addr);
alt_server->host.type = 0;
continue;
}
// ADD, so just reset fail counter
alt_server->failures = 0;
continue;
}
if (dev->new_servers[i].failures == 1) // REMOVE, but server is not in list anyways
continue;
alt_server = get_free_alt_server(dev);
if (alt_server == NULL ) // All NUMBER_SERVERS slots are taken, ignore entry
continue;
// Add new server entry
alt_server->host = dev->new_servers[i].host;
if (alt_server->host.type == HOST_IP4)
debug_dev_va("Adding alt server %pI4", alt_server->host.addr);
else
debug_dev_va("Adding alt server %pI6", alt_server->host.addr);
alt_server->rtts[0] = alt_server->rtts[1] = alt_server->rtts[2] = alt_server->rtts[3] = RTT_UNREACHABLE;
alt_server->protocol_version = 0;
alt_server->failures = 0;
}
dev->new_servers_num = 0;
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
}
current_server = best_server = -1;
best_rtt = 0xFFFFFFFul;
if (dev->heartbeat_count < STARTUP_MODE_DURATION || dev->panic)
{
isize = NUMBER_SERVERS;
}
else
{
isize = 3;
}
if (NUMBER_SERVERS > isize) {
for (i = 0; i < isize; ++i) {
j = ((start.tv_sec >> i) ^ (start.tv_usec >> j)) % NUMBER_SERVERS;
if (j != i) {
mlen = check_order[i];
check_order[i] = check_order[j];
check_order[j] = mlen;
}
}
}
for (j = 0; j < NUMBER_SERVERS; ++j)
{
i = check_order[j];
if (dev->alt_servers[i].host.type == 0) // Empty slot
continue;
if (!dev->panic && dev->alt_servers[i].failures > 50 && (start.tv_usec & 7) != 0) // If not in panic mode, skip server if it failed too many times
continue;
if (isize-- <= 0 && !is_same_server(&dev->cur_server, &dev->alt_servers[i]))
continue;
// Initialize socket and connect
if (dnbd3_sock_create(dev->alt_servers[i].host.type, SOCK_STREAM, IPPROTO_TCP, &sock) < 0)
{
debug_alt("ERROR: Couldn't create socket (discover).");
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;
if (dev->alt_servers[i].host.type == HOST_IP4)
{
sin4.sin_family = AF_INET;
memcpy(&sin4.sin_addr, dev->alt_servers[i].host.addr, 4);
sin4.sin_port = dev->alt_servers[i].host.port;
if (kernel_connect(sock, (struct sockaddr *)&sin4, sizeof(sin4), 0) < 0)
goto error;
}
else
{
sin6.sin6_family = AF_INET6;
memcpy(&sin6.sin6_addr, dev->alt_servers[i].host.addr, 16);
sin6.sin6_port = dev->alt_servers[i].host.port;
if (kernel_connect(sock, (struct sockaddr *)&sin6, sizeof(sin6), 0) < 0)
goto error;
}
// Request filesize
dnbd3_request.cmd = CMD_SELECT_IMAGE;
iov[0].iov_base = &dnbd3_request;
iov[0].iov_len = sizeof(dnbd3_request);
serializer_reset_write(payload);
serializer_put_uint16(payload, PROTOCOL_VERSION); // DNBD3 protocol version
serializer_put_string(payload, dev->imgname); // image name
serializer_put_uint16(payload, dev->rid); // revision id
serializer_put_uint8(payload, 0); // are we a server? (no!)
iov[1].iov_base = payload;
dnbd3_request.size = iov[1].iov_len = serializer_get_written_length(payload);
fixup_request(dnbd3_request);
mlen = iov[1].iov_len + sizeof(dnbd3_request);
if (kernel_sendmsg(sock, &msg, iov, 2, mlen) != mlen)
error_alt("ERROR: Requesting image size failed.");
// 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))
error_alt("ERROR: Receiving image size packet (header) failed (discover).");
fixup_reply(dnbd3_reply);
if (dnbd3_reply.magic != dnbd3_packet_magic || dnbd3_reply.cmd != CMD_SELECT_IMAGE || dnbd3_reply.size < 4)
error_alt("ERROR: Content of image size packet (header) mismatched (discover).");
// 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)
error_alt("ERROR: Receiving image size packet (payload) failed (discover).");
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)
error_alt_va("ERROR: Server version too old (client: %d, server: %d, min supported: %d).",
(int)PROTOCOL_VERSION, (int)dev->alt_servers[i].protocol_version, (int)MIN_SUPPORTED_SERVER);
name = serializer_get_string(payload);
if (name == NULL )
error_alt("ERROR: Server did not supply an image name (discover).");
if (strcmp(name, dev->imgname) != 0)
error_alt_va("ERROR: Image name does not match requested one (client: '%s', server: '%s') (discover).",
dev->imgname, name);
rid = serializer_get_uint16(payload);
if (rid != dev->rid)
error_alt_va("ERROR: Server supplied wrong rid (client: '%d', server: '%d') (discover).",
(int)dev->rid, (int)rid);
filesize = serializer_get_uint64(payload);
if (filesize != dev->reported_size)
error_alt_va("ERROR: Reported image size of %llu does not match expected value %llu.(discover).",
(unsigned long long)filesize, (unsigned long long)dev->reported_size);
// panic mode, take first responding server
if (dev->panic)
{
dev->panic = 0;
debug_alt("WARN: Panic mode, changing server:");
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;
}
// Request block
dnbd3_request.cmd = CMD_GET_BLOCK;
// Do *NOT* pick a random block as it has proven to cause severe
// cache thrashing on the server
dnbd3_request.offset = 0;
dnbd3_request.size = RTT_BLOCK_SIZE;
fixup_request(dnbd3_request);
iov[0].iov_base = &dnbd3_request;
iov[0].iov_len = sizeof(dnbd3_request);
// start rtt measurement
do_gettimeofday(&start);
if (kernel_sendmsg(sock, &msg, iov, 1, sizeof(dnbd3_request)) <= 0)
error_alt("ERROR: Requesting test block failed (discover).");
// 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))
error_alt("ERROR: Receiving test block header packet failed (discover).");
fixup_reply(dnbd3_reply);
if (dnbd3_reply.magic
!= dnbd3_packet_magic|| dnbd3_reply.cmd != CMD_GET_BLOCK || dnbd3_reply.size != RTT_BLOCK_SIZE)
error_alt_va("ERROR: Unexpected reply to block request: cmd=%d, size=%d (discover).",
(int)dnbd3_reply.cmd, (int)dnbd3_reply.size);
// 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)
error_alt("ERROR: Receiving test block payload failed (discover).");
do_gettimeofday(&end); // end rtt measurement
dev->alt_servers[i].rtts[turn] = (unsigned long)((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 (is_same_server(&dev->cur_server, &dev->alt_servers[i]))
{
dev->cur_rtt = rtt;
current_server = i;
}
dev->alt_servers[i].failures = 0;
continue;
error: ;
++dev->alt_servers[i].failures;
sock_release(sock);
sock = NULL;
dev->alt_servers[i].rtts[turn] = RTT_UNREACHABLE;
if (is_same_server(&dev->cur_server, &dev->alt_servers[i]))
{
dev->cur_rtt = RTT_UNREACHABLE;
current_server = i;
}
continue;
}
if (dev->panic)
{
// After 21 retries, bail out by reporting errors to block layer
if (PROBE_COUNT_TIMEOUT > 0 && dev->panic_count < 255 && ++dev->panic_count == PROBE_COUNT_TIMEOUT + 1)
dnbd3_blk_fail_all_requests(dev);
}
if (best_server == -1 || kthread_should_stop() || dev->thread_discover == NULL ) // 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;
}
do_change = ready && best_server != current_server && (start.tv_usec & 3) != 0
&& RTT_THRESHOLD_FACTOR(dev->cur_rtt) > best_rtt + 1500;
if (ready && !do_change) {
spin_lock_irqsave(&dev->blk_lock, irqflags);
if (!list_empty(&dev->request_queue_send))
{
cur_request = list_entry(dev->request_queue_send.next, struct request, queuelist);
do_change = (cur_request == last_request);
if (do_change)
printk("WARNING: Hung request on %s\n", dev->disk->disk_name);
}
else
{
cur_request = (struct request *)123;
}
last_request = cur_request;
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
}
// take server with lowest rtt
if (do_change)
{
printk("INFO: Server %d on %s is faster (%lluµs vs. %lluµs)\n", best_server, dev->disk->disk_name,
(unsigned long long)best_rtt, (unsigned long long)dev->cur_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;
}
if (!ready || (start.tv_usec & 15) != 0)
turn = (turn + 1) % 4;
if (turn == 2) // Set ready when we only have 2 of 4 measurements for quicker load balancing
ready = 1;
}
kfree(buf);
return 0;
}
int dnbd3_net_send(void *data)
{
dnbd3_device_t *dev = data;
struct request *blk_request, *tmp_request;
dnbd3_request_t dnbd3_request;
struct msghdr msg;
struct kvec iov;
unsigned long irqflags;
init_msghdr(msg);
dnbd3_request.magic = dnbd3_packet_magic;
set_user_nice(current, -20);
// move already sent 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_irqsave(&dev->blk_lock, irqflags);
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_irqrestore(&dev->blk_lock, irqflags);
}
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_irqsave(&dev->blk_lock, irqflags);
if (list_empty(&dev->request_queue_send))
{
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
continue;
}
blk_request = list_entry(dev->request_queue_send.next, struct request, queuelist);
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
// what to do?
switch (dnbd3_req_op(blk_request))
{
case DNBD3_DEV_READ:
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_irqsave(&dev->blk_lock, irqflags);
list_del_init(&blk_request->queuelist);
list_add_tail(&blk_request->queuelist, &dev->request_queue_receive);
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
break;
case DNBD3_REQ_OP_SPECIAL:
dnbd3_request.cmd = dnbd3_priv_to_cmd(blk_request);
dnbd3_request.size = 0;
spin_lock_irqsave(&dev->blk_lock, irqflags);
list_del_init(&blk_request->queuelist);
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
break;
default:
printk("ERROR: Unknown command (send %u %u)\n", (int)blk_request->cmd_flags, (int)dnbd3_req_op(blk_request));
spin_lock_irqsave(&dev->blk_lock, irqflags);
list_del_init(&blk_request->queuelist);
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
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))
{
debug_dev("ERROR: Connection to server lost (send)");
goto error;
}
wake_up(&dev->process_queue_receive);
}
dev->thread_send = NULL;
return 0;
error: ;
if (dev->sock)
kernel_sock_shutdown(dev->sock, SHUT_RDWR);
if (!dev->disconnecting)
{
dev->panic = 1;
dev->discover = 1;
wake_up(&dev->process_queue_discover);
}
dev->thread_send = NULL;
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_inst;
struct bio_vec *bvec = &bvec_inst;
void *kaddr;
unsigned long irqflags;
sigset_t blocked, oldset;
uint16_t rid;
unsigned long int recv_timeout = jiffies;
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)
{
if (jiffies < recv_timeout) recv_timeout = jiffies; // Handle overflow
if ((jiffies - recv_timeout) / HZ > SOCKET_KEEPALIVE_TIMEOUT)
error_dev_va("ERROR: Receive timeout reached (%d of %d secs).", (int)((jiffies - recv_timeout) / HZ), (int)SOCKET_KEEPALIVE_TIMEOUT);
continue;
}
if (ret <= 0)
error_dev("ERROR: Connection to server lost (receive)");
if (ret != sizeof(dnbd3_reply))
error_dev("ERROR: Recv msg header.");
fixup_reply(dnbd3_reply);
// check error
if (dnbd3_reply.magic != dnbd3_packet_magic)
error_dev("ERROR: Wrong packet magic (Receive).");
if (dnbd3_reply.cmd == 0)
error_dev("ERROR: Command was 0 (Receive).");
// Update timeout
recv_timeout = jiffies;
// what to do?
switch (dnbd3_reply.cmd)
{
case CMD_GET_BLOCK:
// search for replied request in queue
blk_request = NULL;
spin_lock_irqsave(&dev->blk_lock, irqflags);
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_irqrestore(&dev->blk_lock, irqflags);
if (blk_request == NULL )
error_dev_va("ERROR: Received block data for unrequested handle (%llu: %llu).\n",
(unsigned long long)dnbd3_reply.handle, (unsigned long long)dnbd3_reply.size);
// receive data and answer to block layer
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 14, 0)
rq_for_each_segment(bvec_inst, blk_request, iter)
#else
rq_for_each_segment(bvec, blk_request, iter)
#endif
{
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)
{
kunmap(bvec->bv_page);
sigprocmask(SIG_SETMASK, &oldset, NULL );
error_dev("ERROR: Receiving from net to block layer.");
}
kunmap(bvec->bv_page);
sigprocmask(SIG_SETMASK, &oldset, NULL );
}
spin_lock_irqsave(&dev->blk_lock, irqflags);
list_del_init(&blk_request->queuelist);
__blk_end_request_all(blk_request, 0);
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
continue;
case CMD_GET_SERVERS:
if (!dev->use_server_provided_alts)
{
remaining = dnbd3_reply.size;
goto consume_payload;
}
spin_lock_irqsave(&dev->blk_lock, irqflags);
dev->new_servers_num = 0;
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
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)))
error_dev("ERROR: Recv CMD_GET_SERVERS payload.");
spin_lock_irqsave(&dev->blk_lock, irqflags);
dev->new_servers_num = count;
spin_unlock_irqrestore(&dev->blk_lock, irqflags);
}
// 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;
ret = kernel_recvmsg(dev->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags);
if (ret <= 0)
error_dev("ERROR: Recv additional payload from CMD_GET_SERVERS.");
remaining -= ret;
}
continue;
case CMD_LATEST_RID:
if (dnbd3_reply.size != 2)
{
printk("ERROR: CMD_LATEST_RID.size != 2.\n");
continue;
}
iov.iov_base = &rid;
iov.iov_len = sizeof(rid);
if (kernel_recvmsg(dev->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags) <= 0)
{
printk("ERROR: Could not receive CMD_LATEST_RID payload.\n");
}
else
{
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);
}
continue;
case CMD_KEEPALIVE:
if (dnbd3_reply.size != 0)
printk("ERROR: keep alive packet with payload.\n");
continue;
default:
printk("ERROR: Unknown command (Receive)\n");
continue;
}
}
printk("dnbd3_net_receive terminated normally.\n");
dev->thread_receive = NULL;
return 0;
error:
if (dev->sock)
kernel_sock_shutdown(dev->sock, SHUT_RDWR);
if (!dev->disconnecting)
{
dev->panic = 1;
dev->discover = 1;
wake_up(&dev->process_queue_discover);
}
dev->thread_receive = NULL;
return -1;
}
