/*
* 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)
static int dnbd3_open(struct block_device *bdev, fmode_t mode)
{
dnbd3_device_t *dev = bdev->bd_disk->private_data;
printk(KERN_DEBUG "dnbd3: open device %i\n", dev->minor);
//TODO can be removed?
return 0;
}
static void dnbd3_release(struct gendisk *disk, fmode_t mode)
{
dnbd3_device_t *dev = disk->private_data;
printk(KERN_DEBUG "dnbd3: release device %i\n", dev->minor);
//TODO can be removed?
}
void dnbd3_blk_fail_all_requests(dnbd3_device_t *dev)
{
printk(KERN_DEBUG "dnbd3: fail all requests device %i\n", dev->minor);
}
int dnbd3_net_connect(dnbd3_device_t *dev)
{
struct request *req1 = NULL;
struct timeval timeout;
printk(KERN_DEBUG "dnbd3: net connect device %i\n", dev->minor);
if (dev->disconnecting) {
printk(KERN_DEBUG "dnbd3: device still disconnecting\n");
while (dev->disconnecting)
schedule();
}
if (dev->request) {
printk(KERN_DEBUG "dnbd3: device still in request\n");
while (dev->disconnecting)
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) {
printk(KERN_ERR "dnbd3: kmalloc failed\n");
goto error;
}
if (dev->cur_server.host.port == 0 || dev->cur_server.host.type == 0 || dev->imgname == NULL ) {
printk(KERN_ERR "dnbd3: host, port or image name not set\n");
goto error;
}
if (dev->sock) {
printk(KERN_WARNING "dnbd3: already connected\n");
goto error;
}
if (dev->cur_server.host.type != HOST_IP4 && dev->cur_server.host.type != HOST_IP6) {
printk(KERN_ERR "dnbd3: unknown address type %d\n", (int)dev->cur_server.host.type);
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;
int mlen;
init_msghdr(msg);
if (dnbd3_sock_create(dev->cur_server.host.type, SOCK_STREAM, IPPROTO_TCP, &dev->sock) < 0) {
printk(KERN_ERR "dnbd3: could not 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;
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) {
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), 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){
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(&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) {
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(dev->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 = &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(KERN_ERR "dnbd3: could not read CMD_SELECT_IMAGE payload on handshake\n");
goto error;
}
// 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) {
printk(KERN_ERR "dnbd3: 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(KERN_ERR "dnbd3: server offers image '%s', requested '%s'\n", name, dev->imgname);
goto error;
}
if (strlen(dev->imgname) < strlen(name)) {
dev->imgname = krealloc(dev->imgname, strlen(name) + 1, GFP_ATOMIC );
if (dev->imgname == NULL ) {
printk(KERN_ERR "dnbd3: reallocating buffer for new image name failed\n");
goto error;
}
}
strcpy(dev->imgname, name);
rid = serializer_get_uint16(&dev->payload_buffer);
if (dev->rid != 0 && dev->rid != rid) {
printk(KERN_ERR "dnbd3: server provides rid %d, requested was %d\n", (int)rid, (int)dev->rid);
goto error;
}
dev->rid = rid;
dev->reported_size = serializer_get_uint64(&dev->payload_buffer);
if (dev->reported_size < 4096) {
printk(KERN_ERR "dnbd3: reported size by server is < 4096\n");
goto error;
}
// store image information
set_capacity(dev->disk, dev->reported_size >> 9); /* 512 Byte blocks */
printk(KERN_DEBUG "dnbd3: connected to image %s, filesize %llu\n", dev->imgname, dev->reported_size);
dev->update_available = 0;
} else { // Switching server, connection is already established and size request was executed
printk(KERN_DEBUG "dnbd3: changing server\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;
refcount_inc(&dev->config_refs);
// Enqueue request to request_queue_send for a fresh list of alt servers
//TODO refresh alt server list
// add heartbeat timer
//TODO needed anymore=
// dev->heartbeat_count = 0;
// timer_setup(&dev->hb_timer, dnbd3_net_heartbeat, 0);
// 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)
{
printk(KERN_DEBUG "dnbd3: net disconnect device %i\n", dev->minor);
if (dev->disconnecting) {
return 0;
}
dev->disconnecting = 1;
// clear heartbeat timer
// del_timer(&dev->hb_timer);
dev->discover = 0;
if (dev->sock) {
kernel_sock_shutdown(dev->sock, SHUT_RDWR);
}
// 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;
}
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;
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->cur_server.host)) {
printk(KERN_INFO "dnbd3: odd size bug#1 triggered in ioctl\n");
}
memcpy(&dev->cur_server.host, &msg->host, sizeof(msg->host));
dev->cur_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
if (dnbd3_net_connect(dev) == 0) {
result = 0;
imgname = NULL; // Prevent kfree at the end
} else {
result = -ENOENT;
dev->imgname = NULL;
}
}
break;
case IOCTL_CLOSE:
printk(KERN_DEBUG "dnbd3: ioctl close\n");
dnbd3_blk_fail_all_requests(dev);
result = 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,
.open = dnbd3_open,
.release = dnbd3_release,
.ioctl = dnbd3_ioctl,
.compat_ioctl = dnbd3_ioctl,
};