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* 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/connector.h>
#include <linux/dst.h>
#include <linux/device.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/socket.h>
#include <linux/slab.h>
#include <net/sock.h>
/*
* Polling machinery.
*/
struct dst_poll_helper
{
poll_table pt;
struct dst_state *st;
};
static int dst_queue_wake(wait_queue_t *wait, unsigned mode, int sync, void *key)
{
struct dst_state *st = container_of(wait, struct dst_state, wait);
wake_up(&st->thread_wait);
return 1;
}
static void dst_queue_func(struct file *file, wait_queue_head_t *whead,
poll_table *pt)
{
struct dst_state *st = container_of(pt, struct dst_poll_helper, pt)->st;
st->whead = whead;
init_waitqueue_func_entry(&st->wait, dst_queue_wake);
add_wait_queue(whead, &st->wait);
}
void dst_poll_exit(struct dst_state *st)
{
if (st->whead) {
remove_wait_queue(st->whead, &st->wait);
st->whead = NULL;
}
}
int dst_poll_init(struct dst_state *st)
{
struct dst_poll_helper ph;
ph.st = st;
init_poll_funcptr(&ph.pt, &dst_queue_func);
st->socket->ops->poll(NULL, st->socket, &ph.pt);
return 0;
}
/*
* Header receiving function - may block.
*/
static int dst_data_recv_header(struct socket *sock,
void *data, unsigned int size, int block)
{
struct msghdr msg;
struct kvec iov;
int err;
iov.iov_base = data;
iov.iov_len = size;
msg.msg_iov = (struct iovec *)&iov;
msg.msg_iovlen = 1;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = (block)?MSG_WAITALL:MSG_DONTWAIT;
err = kernel_recvmsg(sock, &msg, &iov, 1, iov.iov_len,
msg.msg_flags);
if (err != size)
return -1;
return 0;
}
/*
* Header sending function - may block.
*/
int dst_data_send_header(struct socket *sock,
void *data, unsigned int size, int more)
{
struct msghdr msg;
struct kvec iov;
int err;
iov.iov_base = data;
iov.iov_len = size;
msg.msg_iov = (struct iovec *)&iov;
msg.msg_iovlen = 1;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = MSG_WAITALL | (more)?MSG_MORE:0;
err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
if (err != size) {
dprintk("%s: size: %u, more: %d, err: %d.\n",
__func__, size, more, err);
return -1;
}
return 0;
}
/*
* Block autoconfiguration: request size of the storage and permissions.
*/
static int dst_request_remote_config(struct dst_state *st)
{
struct dst_node *n = st->node;
int err = -EINVAL;
struct dst_cmd *cmd = st->data;
memset(cmd, 0, sizeof(struct dst_cmd));
cmd->cmd = DST_CFG;
dst_convert_cmd(cmd);
err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0);
if (err)
goto out;
err = dst_data_recv_header(st->socket, cmd, sizeof(struct dst_cmd), 1);
if (err)
goto out;
dst_convert_cmd(cmd);
if (cmd->cmd != DST_CFG) {
err = -EINVAL;
dprintk("%s: checking result: cmd: %d, size reported: %llu.\n",
__func__, cmd->cmd, cmd->sector);
goto out;
}
if (n->size != 0)
n->size = min_t(loff_t, n->size, cmd->sector);
else
n->size = cmd->sector;
n->info->size = n->size;
st->permissions = cmd->rw;
out:
dprintk("%s: n: %p, err: %d, size: %llu, permission: %x.\n",
__func__, n, err, n->size, st->permissions);
return err;
}
/*
* Socket machinery.
*/
#define DST_DEFAULT_TIMEO 20000
int dst_state_socket_create(struct dst_state *st)
{
int err;
struct socket *sock;
struct dst_network_ctl *ctl = &st->ctl;
err = sock_create(ctl->addr.sa_family, ctl->type, ctl->proto, &sock);
if (err < 0)
return err;
sock->sk->sk_sndtimeo = sock->sk->sk_rcvtimeo =
msecs_to_jiffies(DST_DEFAULT_TIMEO);
sock->sk->sk_allocation = GFP_NOIO;
st->socket = st->read_socket = sock;
return 0;
}
void dst_state_socket_release(struct dst_state *st)
{
dprintk("%s: st: %p, socket: %p, n: %p.\n",
__func__, st, st->socket, st->node);
if (st->socket) {
sock_release(st->socket);
st->socket = NULL;
st->read_socket = NULL;
}
}
void dst_dump_addr(struct socket *sk, struct sockaddr *sa, char *str)
{
if (sk->ops->family == AF_INET) {
struct sockaddr_in *sin = (struct sockaddr_in *)sa;
printk(KERN_INFO "%s %u.%u.%u.%u:%d.\n",
str, NIPQUAD(sin->sin_addr.s_addr), ntohs(sin->sin_port));
} else if (sk->ops->family == AF_INET6) {
struct sockaddr_in6 *sin = (struct sockaddr_in6 *)sa;
printk(KERN_INFO "%s %pi6:%d",
str, &sin->sin6_addr, ntohs(sin->sin6_port));
}
}
void dst_state_exit_connected(struct dst_state *st)
{
if (st->socket) {
dst_poll_exit(st);
st->socket->ops->shutdown(st->socket, 2);
dst_dump_addr(st->socket, (struct sockaddr *)&st->ctl.addr,
"Disconnected peer");
dst_state_socket_release(st);
}
}
static int dst_state_init_connected(struct dst_state *st)
{
int err;
struct dst_network_ctl *ctl = &st->ctl;
err = dst_state_socket_create(st);
if (err)
goto err_out_exit;
err = kernel_connect(st->socket, (struct sockaddr *)&st->ctl.addr,
st->ctl.addr.sa_data_len, 0);
if (err)
goto err_out_release;
err = dst_poll_init(st);
if (err)
goto err_out_release;
dst_dump_addr(st->socket, (struct sockaddr *)&ctl->addr,
"Connected to peer");
return 0;
err_out_release:
dst_state_socket_release(st);
err_out_exit:
return err;
}
/*
* State reset is used to reconnect to the remote peer.
* May fail, but who cares, we will try again later.
*/
static void inline dst_state_reset_nolock(struct dst_state *st)
{
dst_state_exit_connected(st);
dst_state_init_connected(st);
}
static void inline dst_state_reset(struct dst_state *st)
{
dst_state_lock(st);
dst_state_reset_nolock(st);
dst_state_unlock(st);
}
/*
* Basic network sending/receiving functions.
* Blocked mode is used.
*/
static int dst_data_recv_raw(struct dst_state *st, void *buf, u64 size)
{
struct msghdr msg;
struct kvec iov;
int err;
BUG_ON(!size);
iov.iov_base = buf;
iov.iov_len = size;
msg.msg_iov = (struct iovec *)&iov;
msg.msg_iovlen = 1;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = MSG_DONTWAIT;
err = kernel_recvmsg(st->socket, &msg, &iov, 1, iov.iov_len,
msg.msg_flags);
if (err <= 0) {
dprintk("%s: failed to recv data: size: %llu, err: %d.\n",
__func__, size, err);
if (err == 0)
err = -ECONNRESET;
dst_state_exit_connected(st);
}
return err;
}
/*
* Ping command to early detect failed nodes.
*/
static int dst_send_ping(struct dst_state *st)
{
struct dst_cmd *cmd = st->data;
int err = -ECONNRESET;
dst_state_lock(st);
if (st->socket) {
memset(cmd, 0, sizeof(struct dst_cmd));
cmd->cmd = __cpu_to_be32(DST_PING);
err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0);
}
dprintk("%s: st: %p, socket: %p, err: %d.\n", __func__, st, st->socket, err);
dst_state_unlock(st);
return err;
}
/*
* Receiving function, which should either return error or read
* whole block request. If there was no traffic for a one second,
* send a ping, since remote node may die.
*/
int dst_data_recv(struct dst_state *st, void *data, unsigned int size)
{
unsigned int revents = 0;
unsigned int err_mask = POLLERR | POLLHUP | POLLRDHUP;
unsigned int mask = err_mask | POLLIN;
struct dst_node *n = st->node;
int err = 0;
while (size && !err) {
revents = dst_state_poll(st);
if (!(revents & mask)) {
DEFINE_WAIT(wait);
for (;;) {
prepare_to_wait(&st->thread_wait, &wait,
TASK_INTERRUPTIBLE);
if (!n->trans_scan_timeout || st->need_exit)
break;
revents = dst_state_poll(st);
if (revents & mask)
break;
if (signal_pending(current))
break;
if (!schedule_timeout(HZ)) {
err = dst_send_ping(st);
if (err)
return err;
}
continue;
}
finish_wait(&st->thread_wait, &wait);
}
err = -ECONNRESET;
dst_state_lock(st);
if ( st->socket &&
(st->read_socket == st->socket) &&
(revents & POLLIN)) {
err = dst_data_recv_raw(st, data, size);
if (err > 0) {
data += err;
size -= err;
err = 0;
}
}
if (revents & err_mask || !st->socket) {
dprintk("%s: revents: %x, socket: %p, size: %u, err: %d.\n",
__func__, revents, st->socket, size, err);
err = -ECONNRESET;
}
dst_state_unlock(st);
if (!n->trans_scan_timeout)
err = -ENODEV;
}
return err;
}
/*
* Send block autoconf reply.
*/
static int dst_process_cfg(struct dst_state *st)
{
struct dst_node *n = st->node;
struct dst_cmd *cmd = st->data;
int err;
cmd->sector = n->size;
cmd->rw = st->permissions;
dst_convert_cmd(cmd);
dst_state_lock(st);
err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0);
dst_state_unlock(st);
return err;
}
/*
* Receive block IO from the network.
*/
static int dst_recv_bio(struct dst_state *st, struct bio *bio, unsigned int total_size)
{
struct bio_vec *bv;
int i, err;
void *data;
unsigned int sz;
bio_for_each_segment(bv, bio, i) {
sz = min(total_size, bv->bv_len);
dprintk("%s: bio: %llu/%u, total: %u, len: %u, sz: %u, off: %u.\n",
__func__, (u64)bio->bi_sector, bio->bi_size, total_size,
bv->bv_len, sz, bv->bv_offset);
data = kmap(bv->bv_page) + bv->bv_offset;
err = dst_data_recv(st, data, sz);
kunmap(bv->bv_page);
bv->bv_len = sz;
if (err)
return err;
total_size -= sz;
if (total_size == 0)
break;
}
return 0;
}
/*
* Our block IO has just completed and arrived: get it.
*/
static int dst_process_io_response(struct dst_state *st)
{
struct dst_node *n = st->node;
struct dst_cmd *cmd = st->data;
struct dst_trans *t;
int err = 0;
struct bio *bio;
mutex_lock(&n->trans_lock);
t = dst_trans_search(n, cmd->id);
mutex_unlock(&n->trans_lock);
if (!t)
goto err_out_exit;
bio = t->bio;
dprintk("%s: bio: %llu/%u, cmd_size: %u, csize: %u, dir: %lu.\n",
__func__, (u64)bio->bi_sector, bio->bi_size, cmd->size,
cmd->csize, bio_data_dir(bio));
if (bio_data_dir(bio) == READ) {
if (bio->bi_size != cmd->size - cmd->csize)
goto err_out_exit;
if (dst_need_crypto(n)) {
err = dst_recv_cdata(st, t->cmd.hash);
if (err)
goto err_out_exit;
}
err = dst_recv_bio(st, t->bio, bio->bi_size);
if (err)
goto err_out_exit;
if (dst_need_crypto(n))
return dst_trans_crypto(t);
} else {
err = -EBADMSG;
if (cmd->size || cmd->csize)
goto err_out_exit;
}
dst_trans_remove(t);
dst_trans_put(t);
return 0;
err_out_exit:
return err;
}
/*
* Receive crypto data.
*/
int dst_recv_cdata(struct dst_state *st, void *cdata)
{
struct dst_cmd *cmd = st->data;
struct dst_node *n = st->node;
struct dst_crypto_ctl *c = &n->crypto;
int err;
if (cmd->csize != c->crypto_attached_size) {
dprintk("%s: cmd: cmd: %u, sector: %llu, size: %u, "
"csize: %u != digest size %u.\n",
__func__, cmd->cmd, cmd->sector, cmd->size,
cmd->csize, c->crypto_attached_size);
err = -EINVAL;
goto err_out_exit;
}
err = dst_data_recv(st, cdata, cmd->csize);
if (err)
goto err_out_exit;
cmd->size -= cmd->csize;
return 0;
err_out_exit:
return err;
}
/*
* Receive the command and start its processing.
*/
static int dst_recv_processing(struct dst_state *st)
{
int err = -EINTR;
struct dst_cmd *cmd = st->data;
/*
* If socket will be reset after this statement, then
* dst_data_recv() will just fail and loop will
* start again, so it can be done without any locks.
*
* st->read_socket is needed to prevents state machine
* breaking between this data reading and subsequent one
* in protocol specific functions during connection reset.
* In case of reset we have to read next command and do
* not expect data for old command to magically appear in
* new connection.
*/
st->read_socket = st->socket;
err = dst_data_recv(st, cmd, sizeof(struct dst_cmd));
if (err)
goto out_exit;
dst_convert_cmd(cmd);
dprintk("%s: cmd: %u, size: %u, csize: %u, id: %llu, "
"sector: %llu, flags: %llx, rw: %llx.\n",
__func__, cmd->cmd, cmd->size,
cmd->csize, cmd->id, cmd->sector,
cmd->flags, cmd->rw);
/*
* This should catch protocol breakage and random garbage instead of commands.
*/
if (unlikely(cmd->csize > st->size - sizeof(struct dst_cmd))) {
err = -EBADMSG;
goto out_exit;
}
err = -EPROTO;
switch (cmd->cmd) {
case DST_IO_RESPONSE:
err = dst_process_io_response(st);
break;
case DST_IO:
err = dst_process_io(st);
break;
case DST_CFG:
err = dst_process_cfg(st);
break;
case DST_PING:
err = 0;
break;
default:
break;
}
out_exit:
return err;
}
/*
* Receiving thread. For the client node we should try to reconnect,
* for accepted client we just drop the state and expect it to reconnect.
*/
static int dst_recv(void *init_data, void *schedule_data)
{
struct dst_state *st = schedule_data;
struct dst_node *n = init_data;
int err = 0;
dprintk("%s: start st: %p, n: %p, scan: %lu, need_exit: %d.\n",
__func__, st, n, n->trans_scan_timeout, st->need_exit);
while (n->trans_scan_timeout && !st->need_exit) {
err = dst_recv_processing(st);
if (err < 0) {
if (!st->ctl.type)
break;
if (!n->trans_scan_timeout || st->need_exit)
break;
dst_state_reset(st);
msleep(1000);
}
}
st->need_exit = 1;
wake_up(&st->thread_wait);
dprintk("%s: freeing receiving socket st: %p.\n", __func__, st);
dst_state_lock(st);
dst_state_exit_connected(st);
dst_state_unlock(st);
dst_state_put(st);
dprintk("%s: freed receiving socket st: %p.\n", __func__, st);
return err;
}
/*
* Network state dies here and borns couple of lines below.
* This object is the main network state processing engine:
* sending, receiving, reconnections, all network related
* tasks are handled on behalf of the state.
*/
static void dst_state_free(struct dst_state *st)
{
dprintk("%s: st: %p.\n", __func__, st);
if (st->cleanup)
st->cleanup(st);
kfree(st->data);
kfree(st);
}
struct dst_state *dst_state_alloc(struct dst_node *n)
{
struct dst_state *st;
int err = -ENOMEM;
st = kzalloc(sizeof(struct dst_state), GFP_KERNEL);
if (!st)
goto err_out_exit;
st->node = n;
st->need_exit = 0;
st->size = PAGE_SIZE;
st->data = kmalloc(st->size, GFP_KERNEL);
if (!st->data)
goto err_out_free;
spin_lock_init(&st->request_lock);
INIT_LIST_HEAD(&st->request_list);
mutex_init(&st->state_lock);
init_waitqueue_head(&st->thread_wait);
/*
* One for processing thread, another one for node itself.
*/
atomic_set(&st->refcnt, 2);
dprintk("%s: st: %p, n: %p.\n", __func__, st, st->node);
return st;
err_out_free:
kfree(st);
err_out_exit:
return ERR_PTR(err);
}
int dst_state_schedule_receiver(struct dst_state *st)
{
return thread_pool_schedule_private(st->node->pool, dst_thread_setup,
dst_recv, st, MAX_SCHEDULE_TIMEOUT, st->node);
}
/*
* Initialize client's connection to the remote peer: allocate state,
* connect and perform block IO autoconfiguration.
*/
int dst_node_init_connected(struct dst_node *n, struct dst_network_ctl *r)
{
struct dst_state *st;
int err = -ENOMEM;
st = dst_state_alloc(n);
if (IS_ERR(st)) {
err = PTR_ERR(st);
goto err_out_exit;
}
memcpy(&st->ctl, r, sizeof(struct dst_network_ctl));
err = dst_state_init_connected(st);
if (err)
goto err_out_free_data;
err = dst_request_remote_config(st);
if (err)
goto err_out_exit_connected;
n->state = st;
err = dst_state_schedule_receiver(st);
if (err)
goto err_out_exit_connected;
return 0;
err_out_exit_connected:
dst_state_exit_connected(st);
err_out_free_data:
dst_state_free(st);
err_out_exit:
n->state = NULL;
return err;
}
void dst_state_put(struct dst_state *st)
{
dprintk("%s: st: %p, refcnt: %d.\n",
__func__, st, atomic_read(&st->refcnt));
if (atomic_dec_and_test(&st->refcnt))
dst_state_free(st);
}
/*
* Send block IO to the network one by one using zero-copy ->sendpage().
*/
int dst_send_bio(struct dst_state *st, struct dst_cmd *cmd, struct bio *bio)
{
struct bio_vec *bv;
struct dst_crypto_ctl *c = &st->node->crypto;
int err, i = 0;
int flags = MSG_WAITALL;
err = dst_data_send_header(st->socket, cmd,
sizeof(struct dst_cmd) + c->crypto_attached_size, bio->bi_vcnt);
if (err)
goto err_out_exit;
bio_for_each_segment(bv, bio, i) {
if (i < bio->bi_vcnt - 1)
flags |= MSG_MORE;
err = kernel_sendpage(st->socket, bv->bv_page, bv->bv_offset,
bv->bv_len, flags);
if (err <= 0)
goto err_out_exit;
}
return 0;
err_out_exit:
dprintk("%s: %d/%d, flags: %x, err: %d.\n",
__func__, i, bio->bi_vcnt, flags, err);
return err;
}
/*
* Send transaction to the remote peer.
*/
int dst_trans_send(struct dst_trans *t)
{
int err;
struct dst_state *st = t->n->state;
struct bio *bio = t->bio;
dst_convert_cmd(&t->cmd);
dst_state_lock(st);
if (!st->socket) {
err = dst_state_init_connected(st);
if (err)
goto err_out_unlock;
}
if (bio_data_dir(bio) == WRITE) {
err = dst_send_bio(st, &t->cmd, t->bio);
} else {
err = dst_data_send_header(st->socket, &t->cmd,
sizeof(struct dst_cmd), 0);
}
if (err)
goto err_out_reset;
dst_state_unlock(st);
return 0;
err_out_reset:
dst_state_reset_nolock(st);
err_out_unlock:
dst_state_unlock(st);
return err;
}
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