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linux-sg2042/fs/dlm/lowcomms.c

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// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
******************************************************************************/
/*
* lowcomms.c
*
* This is the "low-level" comms layer.
*
* It is responsible for sending/receiving messages
* from other nodes in the cluster.
*
* Cluster nodes are referred to by their nodeids. nodeids are
* simply 32 bit numbers to the locking module - if they need to
* be expanded for the cluster infrastructure then that is its
* responsibility. It is this layer's
* responsibility to resolve these into IP address or
* whatever it needs for inter-node communication.
*
* The comms level is two kernel threads that deal mainly with
* the receiving of messages from other nodes and passing them
* up to the mid-level comms layer (which understands the
* message format) for execution by the locking core, and
* a send thread which does all the setting up of connections
* to remote nodes and the sending of data. Threads are not allowed
* to send their own data because it may cause them to wait in times
* of high load. Also, this way, the sending thread can collect together
* messages bound for one node and send them in one block.
*
* lowcomms will choose to use either TCP or SCTP as its transport layer
* depending on the configuration variable 'protocol'. This should be set
* to 0 (default) for TCP or 1 for SCTP. It should be configured using a
* cluster-wide mechanism as it must be the same on all nodes of the cluster
* for the DLM to function.
*
*/
#include <asm/ioctls.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/mutex.h>
#include <linux/sctp.h>
#include <linux/slab.h>
#include <net/sctp/sctp.h>
#include <net/ipv6.h>
#include "dlm_internal.h"
#include "lowcomms.h"
#include "midcomms.h"
#include "config.h"
#define NEEDED_RMEM (4*1024*1024)
#define CONN_HASH_SIZE 32
/* Number of messages to send before rescheduling */
#define MAX_SEND_MSG_COUNT 25
#define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(10000)
struct connection {
struct socket *sock; /* NULL if not connected */
uint32_t nodeid; /* So we know who we are in the list */
struct mutex sock_mutex;
unsigned long flags;
#define CF_READ_PENDING 1
#define CF_WRITE_PENDING 2
#define CF_INIT_PENDING 4
#define CF_IS_OTHERCON 5
#define CF_CLOSE 6
#define CF_APP_LIMITED 7
#define CF_CLOSING 8
#define CF_SHUTDOWN 9
#define CF_CONNECTED 10
struct list_head writequeue; /* List of outgoing writequeue_entries */
spinlock_t writequeue_lock;
void (*connect_action) (struct connection *); /* What to do to connect */
void (*shutdown_action)(struct connection *con); /* What to do to shutdown */
int retries;
#define MAX_CONNECT_RETRIES 3
struct hlist_node list;
struct connection *othercon;
struct work_struct rwork; /* Receive workqueue */
struct work_struct swork; /* Send workqueue */
wait_queue_head_t shutdown_wait; /* wait for graceful shutdown */
unsigned char *rx_buf;
int rx_buflen;
int rx_leftover;
struct rcu_head rcu;
};
#define sock2con(x) ((struct connection *)(x)->sk_user_data)
struct listen_connection {
struct socket *sock;
struct work_struct rwork;
};
/* An entry waiting to be sent */
struct writequeue_entry {
struct list_head list;
struct page *page;
int offset;
int len;
int end;
int users;
struct connection *con;
};
struct dlm_node_addr {
struct list_head list;
int nodeid;
int addr_count;
int curr_addr_index;
struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
};
static struct listen_sock_callbacks {
void (*sk_error_report)(struct sock *);
void (*sk_data_ready)(struct sock *);
void (*sk_state_change)(struct sock *);
void (*sk_write_space)(struct sock *);
} listen_sock;
static LIST_HEAD(dlm_node_addrs);
static DEFINE_SPINLOCK(dlm_node_addrs_spin);
static struct listen_connection listen_con;
static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
static int dlm_local_count;
static int dlm_allow_conn;
/* Work queues */
static struct workqueue_struct *recv_workqueue;
static struct workqueue_struct *send_workqueue;
static struct hlist_head connection_hash[CONN_HASH_SIZE];
static DEFINE_SPINLOCK(connections_lock);
DEFINE_STATIC_SRCU(connections_srcu);
static void process_recv_sockets(struct work_struct *work);
static void process_send_sockets(struct work_struct *work);
static void sctp_connect_to_sock(struct connection *con);
static void tcp_connect_to_sock(struct connection *con);
static void dlm_tcp_shutdown(struct connection *con);
/* This is deliberately very simple because most clusters have simple
sequential nodeids, so we should be able to go straight to a connection
struct in the array */
static inline int nodeid_hash(int nodeid)
{
return nodeid & (CONN_HASH_SIZE-1);
}
static struct connection *__find_con(int nodeid)
{
int r, idx;
struct connection *con;
r = nodeid_hash(nodeid);
idx = srcu_read_lock(&connections_srcu);
hlist_for_each_entry_rcu(con, &connection_hash[r], list) {
if (con->nodeid == nodeid) {
srcu_read_unlock(&connections_srcu, idx);
return con;
}
}
srcu_read_unlock(&connections_srcu, idx);
return NULL;
}
static int dlm_con_init(struct connection *con, int nodeid)
{
con->rx_buflen = dlm_config.ci_buffer_size;
con->rx_buf = kmalloc(con->rx_buflen, GFP_NOFS);
if (!con->rx_buf)
return -ENOMEM;
con->nodeid = nodeid;
mutex_init(&con->sock_mutex);
INIT_LIST_HEAD(&con->writequeue);
spin_lock_init(&con->writequeue_lock);
INIT_WORK(&con->swork, process_send_sockets);
INIT_WORK(&con->rwork, process_recv_sockets);
init_waitqueue_head(&con->shutdown_wait);
if (dlm_config.ci_protocol == 0) {
con->connect_action = tcp_connect_to_sock;
con->shutdown_action = dlm_tcp_shutdown;
} else {
con->connect_action = sctp_connect_to_sock;
}
return 0;
}
/*
* If 'allocation' is zero then we don't attempt to create a new
* connection structure for this node.
*/
static struct connection *nodeid2con(int nodeid, gfp_t alloc)
{
struct connection *con, *tmp;
int r, ret;
con = __find_con(nodeid);
if (con || !alloc)
return con;
con = kzalloc(sizeof(*con), alloc);
if (!con)
return NULL;
ret = dlm_con_init(con, nodeid);
if (ret) {
kfree(con);
return NULL;
}
r = nodeid_hash(nodeid);
spin_lock(&connections_lock);
/* Because multiple workqueues/threads calls this function it can
* race on multiple cpu's. Instead of locking hot path __find_con()
* we just check in rare cases of recently added nodes again
* under protection of connections_lock. If this is the case we
* abort our connection creation and return the existing connection.
*/
tmp = __find_con(nodeid);
if (tmp) {
spin_unlock(&connections_lock);
kfree(con->rx_buf);
kfree(con);
return tmp;
}
hlist_add_head_rcu(&con->list, &connection_hash[r]);
spin_unlock(&connections_lock);
return con;
}
/* Loop round all connections */
static void foreach_conn(void (*conn_func)(struct connection *c))
{
int i, idx;
struct connection *con;
idx = srcu_read_lock(&connections_srcu);
for (i = 0; i < CONN_HASH_SIZE; i++) {
hlist_for_each_entry_rcu(con, &connection_hash[i], list)
conn_func(con);
}
srcu_read_unlock(&connections_srcu, idx);
}
static struct dlm_node_addr *find_node_addr(int nodeid)
{
struct dlm_node_addr *na;
list_for_each_entry(na, &dlm_node_addrs, list) {
if (na->nodeid == nodeid)
return na;
}
return NULL;
}
static int addr_compare(const struct sockaddr_storage *x,
const struct sockaddr_storage *y)
{
switch (x->ss_family) {
case AF_INET: {
struct sockaddr_in *sinx = (struct sockaddr_in *)x;
struct sockaddr_in *siny = (struct sockaddr_in *)y;
if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
return 0;
if (sinx->sin_port != siny->sin_port)
return 0;
break;
}
case AF_INET6: {
struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
return 0;
if (sinx->sin6_port != siny->sin6_port)
return 0;
break;
}
default:
return 0;
}
return 1;
}
static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
struct sockaddr *sa_out, bool try_new_addr)
{
struct sockaddr_storage sas;
struct dlm_node_addr *na;
if (!dlm_local_count)
return -1;
spin_lock(&dlm_node_addrs_spin);
na = find_node_addr(nodeid);
if (na && na->addr_count) {
memcpy(&sas, na->addr[na->curr_addr_index],
sizeof(struct sockaddr_storage));
if (try_new_addr) {
na->curr_addr_index++;
if (na->curr_addr_index == na->addr_count)
na->curr_addr_index = 0;
}
}
spin_unlock(&dlm_node_addrs_spin);
if (!na)
return -EEXIST;
if (!na->addr_count)
return -ENOENT;
if (sas_out)
memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
if (!sa_out)
return 0;
if (dlm_local_addr[0]->ss_family == AF_INET) {
struct sockaddr_in *in4 = (struct sockaddr_in *) &sas;
struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
} else {
struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &sas;
struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
ret6->sin6_addr = in6->sin6_addr;
}
return 0;
}
static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
{
struct dlm_node_addr *na;
int rv = -EEXIST;
int addr_i;
spin_lock(&dlm_node_addrs_spin);
list_for_each_entry(na, &dlm_node_addrs, list) {
if (!na->addr_count)
continue;
for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
if (addr_compare(na->addr[addr_i], addr)) {
*nodeid = na->nodeid;
rv = 0;
goto unlock;
}
}
}
unlock:
spin_unlock(&dlm_node_addrs_spin);
return rv;
}
/* caller need to held dlm_node_addrs_spin lock */
static bool dlm_lowcomms_na_has_addr(const struct dlm_node_addr *na,
const struct sockaddr_storage *addr)
{
int i;
for (i = 0; i < na->addr_count; i++) {
if (addr_compare(na->addr[i], addr))
return true;
}
return false;
}
int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
{
struct sockaddr_storage *new_addr;
struct dlm_node_addr *new_node, *na;
bool ret;
new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
if (!new_node)
return -ENOMEM;
new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
if (!new_addr) {
kfree(new_node);
return -ENOMEM;
}
memcpy(new_addr, addr, len);
spin_lock(&dlm_node_addrs_spin);
na = find_node_addr(nodeid);
if (!na) {
new_node->nodeid = nodeid;
new_node->addr[0] = new_addr;
new_node->addr_count = 1;
list_add(&new_node->list, &dlm_node_addrs);
spin_unlock(&dlm_node_addrs_spin);
return 0;
}
ret = dlm_lowcomms_na_has_addr(na, addr);
if (ret) {
spin_unlock(&dlm_node_addrs_spin);
kfree(new_addr);
kfree(new_node);
return -EEXIST;
}
if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
spin_unlock(&dlm_node_addrs_spin);
kfree(new_addr);
kfree(new_node);
return -ENOSPC;
}
na->addr[na->addr_count++] = new_addr;
spin_unlock(&dlm_node_addrs_spin);
kfree(new_node);
return 0;
}
/* Data available on socket or listen socket received a connect */
static void lowcomms_data_ready(struct sock *sk)
{
struct connection *con;
read_lock_bh(&sk->sk_callback_lock);
con = sock2con(sk);
if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
queue_work(recv_workqueue, &con->rwork);
read_unlock_bh(&sk->sk_callback_lock);
}
static void lowcomms_listen_data_ready(struct sock *sk)
{
queue_work(recv_workqueue, &listen_con.rwork);
}
static void lowcomms_write_space(struct sock *sk)
{
struct connection *con;
read_lock_bh(&sk->sk_callback_lock);
con = sock2con(sk);
if (!con)
goto out;
if (!test_and_set_bit(CF_CONNECTED, &con->flags)) {
log_print("successful connected to node %d", con->nodeid);
queue_work(send_workqueue, &con->swork);
goto out;
}
clear_bit(SOCK_NOSPACE, &con->sock->flags);
if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
con->sock->sk->sk_write_pending--;
clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
}
queue_work(send_workqueue, &con->swork);
out:
read_unlock_bh(&sk->sk_callback_lock);
}
static inline void lowcomms_connect_sock(struct connection *con)
{
if (test_bit(CF_CLOSE, &con->flags))
return;
queue_work(send_workqueue, &con->swork);
cond_resched();
}
static void lowcomms_state_change(struct sock *sk)
{
/* SCTP layer is not calling sk_data_ready when the connection
* is done, so we catch the signal through here. Also, it
* doesn't switch socket state when entering shutdown, so we
* skip the write in that case.
*/
if (sk->sk_shutdown) {
if (sk->sk_shutdown == RCV_SHUTDOWN)
lowcomms_data_ready(sk);
} else if (sk->sk_state == TCP_ESTABLISHED) {
lowcomms_write_space(sk);
}
}
int dlm_lowcomms_connect_node(int nodeid)
{
struct connection *con;
if (nodeid == dlm_our_nodeid())
return 0;
con = nodeid2con(nodeid, GFP_NOFS);
if (!con)
return -ENOMEM;
lowcomms_connect_sock(con);
return 0;
}
static void lowcomms_error_report(struct sock *sk)
{
struct connection *con;
struct sockaddr_storage saddr;
void (*orig_report)(struct sock *) = NULL;
read_lock_bh(&sk->sk_callback_lock);
con = sock2con(sk);
if (con == NULL)
goto out;
orig_report = listen_sock.sk_error_report;
if (con->sock == NULL ||
kernel_getpeername(con->sock, (struct sockaddr *)&saddr) < 0) {
printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
"sending to node %d, port %d, "
"sk_err=%d/%d\n", dlm_our_nodeid(),
con->nodeid, dlm_config.ci_tcp_port,
sk->sk_err, sk->sk_err_soft);
} else if (saddr.ss_family == AF_INET) {
struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
"sending to node %d at %pI4, port %d, "
"sk_err=%d/%d\n", dlm_our_nodeid(),
con->nodeid, &sin4->sin_addr.s_addr,
dlm_config.ci_tcp_port, sk->sk_err,
sk->sk_err_soft);
} else {
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
"sending to node %d at %u.%u.%u.%u, "
"port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
con->nodeid, sin6->sin6_addr.s6_addr32[0],
sin6->sin6_addr.s6_addr32[1],
sin6->sin6_addr.s6_addr32[2],
sin6->sin6_addr.s6_addr32[3],
dlm_config.ci_tcp_port, sk->sk_err,
sk->sk_err_soft);
}
out:
read_unlock_bh(&sk->sk_callback_lock);
if (orig_report)
orig_report(sk);
}
/* Note: sk_callback_lock must be locked before calling this function. */
static void save_listen_callbacks(struct socket *sock)
{
struct sock *sk = sock->sk;
listen_sock.sk_data_ready = sk->sk_data_ready;
listen_sock.sk_state_change = sk->sk_state_change;
listen_sock.sk_write_space = sk->sk_write_space;
listen_sock.sk_error_report = sk->sk_error_report;
}
static void restore_callbacks(struct socket *sock)
{
struct sock *sk = sock->sk;
write_lock_bh(&sk->sk_callback_lock);
sk->sk_user_data = NULL;
sk->sk_data_ready = listen_sock.sk_data_ready;
sk->sk_state_change = listen_sock.sk_state_change;
sk->sk_write_space = listen_sock.sk_write_space;
sk->sk_error_report = listen_sock.sk_error_report;
write_unlock_bh(&sk->sk_callback_lock);
}
static void add_listen_sock(struct socket *sock, struct listen_connection *con)
{
struct sock *sk = sock->sk;
write_lock_bh(&sk->sk_callback_lock);
save_listen_callbacks(sock);
con->sock = sock;
sk->sk_user_data = con;
sk->sk_allocation = GFP_NOFS;
/* Install a data_ready callback */
sk->sk_data_ready = lowcomms_listen_data_ready;
write_unlock_bh(&sk->sk_callback_lock);
}
/* Make a socket active */
static void add_sock(struct socket *sock, struct connection *con)
{
struct sock *sk = sock->sk;
write_lock_bh(&sk->sk_callback_lock);
con->sock = sock;
sk->sk_user_data = con;
/* Install a data_ready callback */
sk->sk_data_ready = lowcomms_data_ready;
sk->sk_write_space = lowcomms_write_space;
sk->sk_state_change = lowcomms_state_change;
sk->sk_allocation = GFP_NOFS;
sk->sk_error_report = lowcomms_error_report;
write_unlock_bh(&sk->sk_callback_lock);
}
/* Add the port number to an IPv6 or 4 sockaddr and return the address
length */
static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
int *addr_len)
{
saddr->ss_family = dlm_local_addr[0]->ss_family;
if (saddr->ss_family == AF_INET) {
struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
in4_addr->sin_port = cpu_to_be16(port);
*addr_len = sizeof(struct sockaddr_in);
memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
} else {
struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
in6_addr->sin6_port = cpu_to_be16(port);
*addr_len = sizeof(struct sockaddr_in6);
}
memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
}
static void dlm_close_sock(struct socket **sock)
{
if (*sock) {
restore_callbacks(*sock);
sock_release(*sock);
*sock = NULL;
}
}
/* Close a remote connection and tidy up */
static void close_connection(struct connection *con, bool and_other,
bool tx, bool rx)
{
bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
if (tx && !closing && cancel_work_sync(&con->swork)) {
log_print("canceled swork for node %d", con->nodeid);
clear_bit(CF_WRITE_PENDING, &con->flags);
}
if (rx && !closing && cancel_work_sync(&con->rwork)) {
log_print("canceled rwork for node %d", con->nodeid);
clear_bit(CF_READ_PENDING, &con->flags);
}
mutex_lock(&con->sock_mutex);
dlm_close_sock(&con->sock);
if (con->othercon && and_other) {
/* Will only re-enter once. */
close_connection(con->othercon, false, true, true);
}
con->rx_leftover = 0;
con->retries = 0;
clear_bit(CF_CONNECTED, &con->flags);
mutex_unlock(&con->sock_mutex);
clear_bit(CF_CLOSING, &con->flags);
}
static void shutdown_connection(struct connection *con)
{
int ret;
if (cancel_work_sync(&con->swork)) {
log_print("canceled swork for node %d", con->nodeid);
clear_bit(CF_WRITE_PENDING, &con->flags);
}
mutex_lock(&con->sock_mutex);
/* nothing to shutdown */
if (!con->sock) {
mutex_unlock(&con->sock_mutex);
return;
}
set_bit(CF_SHUTDOWN, &con->flags);
ret = kernel_sock_shutdown(con->sock, SHUT_WR);
mutex_unlock(&con->sock_mutex);
if (ret) {
log_print("Connection %p failed to shutdown: %d will force close",
con, ret);
goto force_close;
} else {
ret = wait_event_timeout(con->shutdown_wait,
!test_bit(CF_SHUTDOWN, &con->flags),
DLM_SHUTDOWN_WAIT_TIMEOUT);
if (ret == 0) {
log_print("Connection %p shutdown timed out, will force close",
con);
goto force_close;
}
}
return;
force_close:
clear_bit(CF_SHUTDOWN, &con->flags);
close_connection(con, false, true, true);
}
static void dlm_tcp_shutdown(struct connection *con)
{
if (con->othercon)
shutdown_connection(con->othercon);
shutdown_connection(con);
}
static int con_realloc_receive_buf(struct connection *con, int newlen)
{
unsigned char *newbuf;
newbuf = kmalloc(newlen, GFP_NOFS);
if (!newbuf)
return -ENOMEM;
/* copy any leftover from last receive */
if (con->rx_leftover)
memmove(newbuf, con->rx_buf, con->rx_leftover);
/* swap to new buffer space */
kfree(con->rx_buf);
con->rx_buflen = newlen;
con->rx_buf = newbuf;
return 0;
}
/* Data received from remote end */
static int receive_from_sock(struct connection *con)
{
int call_again_soon = 0;
struct msghdr msg;
struct kvec iov;
int ret, buflen;
mutex_lock(&con->sock_mutex);
if (con->sock == NULL) {
ret = -EAGAIN;
goto out_close;
}
/* realloc if we get new buffer size to read out */
buflen = dlm_config.ci_buffer_size;
if (con->rx_buflen != buflen && con->rx_leftover <= buflen) {
ret = con_realloc_receive_buf(con, buflen);
if (ret < 0)
goto out_resched;
}
/* calculate new buffer parameter regarding last receive and
* possible leftover bytes
*/
iov.iov_base = con->rx_buf + con->rx_leftover;
iov.iov_len = con->rx_buflen - con->rx_leftover;
memset(&msg, 0, sizeof(msg));
msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
msg.msg_flags);
if (ret <= 0)
goto out_close;
else if (ret == iov.iov_len)
call_again_soon = 1;
/* new buflen according readed bytes and leftover from last receive */
buflen = ret + con->rx_leftover;
ret = dlm_process_incoming_buffer(con->nodeid, con->rx_buf, buflen);
if (ret < 0)
goto out_close;
/* calculate leftover bytes from process and put it into begin of
* the receive buffer, so next receive we have the full message
* at the start address of the receive buffer.
*/
con->rx_leftover = buflen - ret;
if (con->rx_leftover) {
memmove(con->rx_buf, con->rx_buf + ret,
con->rx_leftover);
call_again_soon = true;
}
if (call_again_soon)
goto out_resched;
mutex_unlock(&con->sock_mutex);
return 0;
out_resched:
if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
queue_work(recv_workqueue, &con->rwork);
mutex_unlock(&con->sock_mutex);
return -EAGAIN;
out_close:
mutex_unlock(&con->sock_mutex);
if (ret != -EAGAIN) {
/* Reconnect when there is something to send */
close_connection(con, false, true, false);
if (ret == 0) {
log_print("connection %p got EOF from %d",
con, con->nodeid);
/* handling for tcp shutdown */
clear_bit(CF_SHUTDOWN, &con->flags);
wake_up(&con->shutdown_wait);
/* signal to breaking receive worker */
ret = -1;
}
}
return ret;
}
/* Listening socket is busy, accept a connection */
static int accept_from_sock(struct listen_connection *con)
{
int result;
struct sockaddr_storage peeraddr;
struct socket *newsock;
int len;
int nodeid;
struct connection *newcon;
struct connection *addcon;
unsigned int mark;
if (!dlm_allow_conn) {
return -1;
}
if (!con->sock)
return -ENOTCONN;
result = kernel_accept(con->sock, &newsock, O_NONBLOCK);
if (result < 0)
goto accept_err;
/* Get the connected socket's peer */
memset(&peeraddr, 0, sizeof(peeraddr));
len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2);
if (len < 0) {
result = -ECONNABORTED;
goto accept_err;
}
/* Get the new node's NODEID */
make_sockaddr(&peeraddr, 0, &len);
if (addr_to_nodeid(&peeraddr, &nodeid)) {
unsigned char *b=(unsigned char *)&peeraddr;
log_print("connect from non cluster node");
print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
b, sizeof(struct sockaddr_storage));
sock_release(newsock);
return -1;
}
dlm_comm_mark(nodeid, &mark);
sock_set_mark(newsock->sk, mark);
log_print("got connection from %d", nodeid);
/* Check to see if we already have a connection to this node. This
* could happen if the two nodes initiate a connection at roughly
* the same time and the connections cross on the wire.
* In this case we store the incoming one in "othercon"
*/
newcon = nodeid2con(nodeid, GFP_NOFS);
if (!newcon) {
result = -ENOMEM;
goto accept_err;
}
mutex_lock(&newcon->sock_mutex);
if (newcon->sock) {
struct connection *othercon = newcon->othercon;
if (!othercon) {
othercon = kzalloc(sizeof(*othercon), GFP_NOFS);
if (!othercon) {
log_print("failed to allocate incoming socket");
mutex_unlock(&newcon->sock_mutex);
result = -ENOMEM;
goto accept_err;
}
result = dlm_con_init(othercon, nodeid);
if (result < 0) {
kfree(othercon);
goto accept_err;
}
newcon->othercon = othercon;
} else {
/* close other sock con if we have something new */
close_connection(othercon, false, true, false);
}
mutex_lock_nested(&othercon->sock_mutex, 1);
add_sock(newsock, othercon);
addcon = othercon;
mutex_unlock(&othercon->sock_mutex);
}
else {
/* accept copies the sk after we've saved the callbacks, so we
don't want to save them a second time or comm errors will
result in calling sk_error_report recursively. */
add_sock(newsock, newcon);
addcon = newcon;
}
mutex_unlock(&newcon->sock_mutex);
/*
* Add it to the active queue in case we got data
* between processing the accept adding the socket
* to the read_sockets list
*/
if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
queue_work(recv_workqueue, &addcon->rwork);
return 0;
accept_err:
if (newsock)
sock_release(newsock);
if (result != -EAGAIN)
log_print("error accepting connection from node: %d", result);
return result;
}
static void free_entry(struct writequeue_entry *e)
{
__free_page(e->page);
kfree(e);
}
/*
* writequeue_entry_complete - try to delete and free write queue entry
* @e: write queue entry to try to delete
* @completed: bytes completed
*
* writequeue_lock must be held.
*/
static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
{
e->offset += completed;
e->len -= completed;
if (e->len == 0 && e->users == 0) {
list_del(&e->list);
free_entry(e);
}
}
/*
* sctp_bind_addrs - bind a SCTP socket to all our addresses
*/
static int sctp_bind_addrs(struct socket *sock, uint16_t port)
{
struct sockaddr_storage localaddr;
struct sockaddr *addr = (struct sockaddr *)&localaddr;
int i, addr_len, result = 0;
for (i = 0; i < dlm_local_count; i++) {
memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
make_sockaddr(&localaddr, port, &addr_len);
if (!i)
result = kernel_bind(sock, addr, addr_len);
else
result = sock_bind_add(sock->sk, addr, addr_len);
if (result < 0) {
log_print("Can't bind to %d addr number %d, %d.\n",
port, i + 1, result);
break;
}
}
return result;
}
/* Initiate an SCTP association.
This is a special case of send_to_sock() in that we don't yet have a
peeled-off socket for this association, so we use the listening socket
and add the primary IP address of the remote node.
*/
static void sctp_connect_to_sock(struct connection *con)
{
struct sockaddr_storage daddr;
int result;
int addr_len;
struct socket *sock;
unsigned int mark;
dlm_comm_mark(con->nodeid, &mark);
mutex_lock(&con->sock_mutex);
/* Some odd races can cause double-connects, ignore them */
if (con->retries++ > MAX_CONNECT_RETRIES)
goto out;
if (con->sock) {
log_print("node %d already connected.", con->nodeid);
goto out;
}
memset(&daddr, 0, sizeof(daddr));
result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
if (result < 0) {
log_print("no address for nodeid %d", con->nodeid);
goto out;
}
/* Create a socket to communicate with */
result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
SOCK_STREAM, IPPROTO_SCTP, &sock);
if (result < 0)
goto socket_err;
sock_set_mark(sock->sk, mark);
add_sock(sock, con);
/* Bind to all addresses. */
if (sctp_bind_addrs(con->sock, 0))
goto bind_err;
make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
log_print("connecting to %d", con->nodeid);
/* Turn off Nagle's algorithm */
sctp_sock_set_nodelay(sock->sk);
/*
* Make sock->ops->connect() function return in specified time,
* since O_NONBLOCK argument in connect() function does not work here,
* then, we should restore the default value of this attribute.
*/
sock_set_sndtimeo(sock->sk, 5);
result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
0);
sock_set_sndtimeo(sock->sk, 0);
if (result == -EINPROGRESS)
result = 0;
if (result == 0) {
if (!test_and_set_bit(CF_CONNECTED, &con->flags))
log_print("successful connected to node %d", con->nodeid);
goto out;
}
bind_err:
con->sock = NULL;
sock_release(sock);
socket_err:
/*
* Some errors are fatal and this list might need adjusting. For other
* errors we try again until the max number of retries is reached.
*/
if (result != -EHOSTUNREACH &&
result != -ENETUNREACH &&
result != -ENETDOWN &&
result != -EINVAL &&
result != -EPROTONOSUPPORT) {
log_print("connect %d try %d error %d", con->nodeid,
con->retries, result);
mutex_unlock(&con->sock_mutex);
msleep(1000);
lowcomms_connect_sock(con);
return;
}
out:
mutex_unlock(&con->sock_mutex);
}
/* Connect a new socket to its peer */
static void tcp_connect_to_sock(struct connection *con)
{
struct sockaddr_storage saddr, src_addr;
int addr_len;
struct socket *sock = NULL;
unsigned int mark;
int result;
dlm_comm_mark(con->nodeid, &mark);
mutex_lock(&con->sock_mutex);
if (con->retries++ > MAX_CONNECT_RETRIES)
goto out;
/* Some odd races can cause double-connects, ignore them */
if (con->sock)
goto out;
/* Create a socket to communicate with */
result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
SOCK_STREAM, IPPROTO_TCP, &sock);
if (result < 0)
goto out_err;
sock_set_mark(sock->sk, mark);
memset(&saddr, 0, sizeof(saddr));
result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
if (result < 0) {
log_print("no address for nodeid %d", con->nodeid);
goto out_err;
}
add_sock(sock, con);
/* Bind to our cluster-known address connecting to avoid
routing problems */
memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
make_sockaddr(&src_addr, 0, &addr_len);
result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
addr_len);
if (result < 0) {
log_print("could not bind for connect: %d", result);
/* This *may* not indicate a critical error */
}
make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
log_print("connecting to %d", con->nodeid);
/* Turn off Nagle's algorithm */
tcp_sock_set_nodelay(sock->sk);
result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
O_NONBLOCK);
if (result == -EINPROGRESS)
result = 0;
if (result == 0)
goto out;
out_err:
if (con->sock) {
sock_release(con->sock);
con->sock = NULL;
} else if (sock) {
sock_release(sock);
}
/*
* Some errors are fatal and this list might need adjusting. For other
* errors we try again until the max number of retries is reached.
*/
if (result != -EHOSTUNREACH &&
result != -ENETUNREACH &&
result != -ENETDOWN &&
result != -EINVAL &&
result != -EPROTONOSUPPORT) {
log_print("connect %d try %d error %d", con->nodeid,
con->retries, result);
mutex_unlock(&con->sock_mutex);
msleep(1000);
lowcomms_connect_sock(con);
return;
}
out:
mutex_unlock(&con->sock_mutex);
return;
}
/* On error caller must run dlm_close_sock() for the
* listen connection socket.
*/
static int tcp_create_listen_sock(struct listen_connection *con,
struct sockaddr_storage *saddr)
{
struct socket *sock = NULL;
int result = 0;
int addr_len;
if (dlm_local_addr[0]->ss_family == AF_INET)
addr_len = sizeof(struct sockaddr_in);
else
addr_len = sizeof(struct sockaddr_in6);
/* Create a socket to communicate with */
result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
SOCK_STREAM, IPPROTO_TCP, &sock);
if (result < 0) {
log_print("Can't create listening comms socket");
goto create_out;
}
sock_set_mark(sock->sk, dlm_config.ci_mark);
/* Turn off Nagle's algorithm */
tcp_sock_set_nodelay(sock->sk);
sock_set_reuseaddr(sock->sk);
add_listen_sock(sock, con);
/* Bind to our port */
make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
if (result < 0) {
log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
goto create_out;
}
sock_set_keepalive(sock->sk);
result = sock->ops->listen(sock, 5);
if (result < 0) {
log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
goto create_out;
}
return 0;
create_out:
return result;
}
/* Get local addresses */
static void init_local(void)
{
struct sockaddr_storage sas, *addr;
int i;
dlm_local_count = 0;
for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
if (dlm_our_addr(&sas, i))
break;
addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
if (!addr)
break;
dlm_local_addr[dlm_local_count++] = addr;
}
}
static void deinit_local(void)
{
int i;
for (i = 0; i < dlm_local_count; i++)
kfree(dlm_local_addr[i]);
}
/* Initialise SCTP socket and bind to all interfaces
* On error caller must run dlm_close_sock() for the
* listen connection socket.
*/
static int sctp_listen_for_all(struct listen_connection *con)
{
struct socket *sock = NULL;
int result = -EINVAL;
log_print("Using SCTP for communications");
result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
SOCK_STREAM, IPPROTO_SCTP, &sock);
if (result < 0) {
log_print("Can't create comms socket, check SCTP is loaded");
goto out;
}
sock_set_rcvbuf(sock->sk, NEEDED_RMEM);
sock_set_mark(sock->sk, dlm_config.ci_mark);
sctp_sock_set_nodelay(sock->sk);
add_listen_sock(sock, con);
/* Bind to all addresses. */
result = sctp_bind_addrs(con->sock, dlm_config.ci_tcp_port);
if (result < 0)
goto out;
result = sock->ops->listen(sock, 5);
if (result < 0) {
log_print("Can't set socket listening");
goto out;
}
return 0;
out:
return result;
}
static int tcp_listen_for_all(void)
{
/* We don't support multi-homed hosts */
if (dlm_local_count > 1) {
log_print("TCP protocol can't handle multi-homed hosts, "
"try SCTP");
return -EINVAL;
}
log_print("Using TCP for communications");
return tcp_create_listen_sock(&listen_con, dlm_local_addr[0]);
}
static struct writequeue_entry *new_writequeue_entry(struct connection *con,
gfp_t allocation)
{
struct writequeue_entry *entry;
entry = kmalloc(sizeof(struct writequeue_entry), allocation);
if (!entry)
return NULL;
entry->page = alloc_page(allocation);
if (!entry->page) {
kfree(entry);
return NULL;
}
entry->offset = 0;
entry->len = 0;
entry->end = 0;
entry->users = 0;
entry->con = con;
return entry;
}
void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
{
struct connection *con;
struct writequeue_entry *e;
int offset = 0;
if (len > LOWCOMMS_MAX_TX_BUFFER_LEN) {
BUILD_BUG_ON(PAGE_SIZE < LOWCOMMS_MAX_TX_BUFFER_LEN);
log_print("failed to allocate a buffer of size %d", len);
return NULL;
}
con = nodeid2con(nodeid, allocation);
if (!con)
return NULL;
spin_lock(&con->writequeue_lock);
e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
if ((&e->list == &con->writequeue) ||
(PAGE_SIZE - e->end < len)) {
e = NULL;
} else {
offset = e->end;
e->end += len;
e->users++;
}
spin_unlock(&con->writequeue_lock);
if (e) {
got_one:
*ppc = page_address(e->page) + offset;
return e;
}
e = new_writequeue_entry(con, allocation);
if (e) {
spin_lock(&con->writequeue_lock);
offset = e->end;
e->end += len;
e->users++;
list_add_tail(&e->list, &con->writequeue);
spin_unlock(&con->writequeue_lock);
goto got_one;
}
return NULL;
}
void dlm_lowcomms_commit_buffer(void *mh)
{
struct writequeue_entry *e = (struct writequeue_entry *)mh;
struct connection *con = e->con;
int users;
spin_lock(&con->writequeue_lock);
users = --e->users;
if (users)
goto out;
e->len = e->end - e->offset;
spin_unlock(&con->writequeue_lock);
queue_work(send_workqueue, &con->swork);
return;
out:
spin_unlock(&con->writequeue_lock);
return;
}
/* Send a message */
static void send_to_sock(struct connection *con)
{
int ret = 0;
const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
struct writequeue_entry *e;
int len, offset;
int count = 0;
mutex_lock(&con->sock_mutex);
if (con->sock == NULL)
goto out_connect;
spin_lock(&con->writequeue_lock);
for (;;) {
e = list_entry(con->writequeue.next, struct writequeue_entry,
list);
if ((struct list_head *) e == &con->writequeue)
break;
len = e->len;
offset = e->offset;
BUG_ON(len == 0 && e->users == 0);
spin_unlock(&con->writequeue_lock);
ret = 0;
if (len) {
ret = kernel_sendpage(con->sock, e->page, offset, len,
msg_flags);
if (ret == -EAGAIN || ret == 0) {
if (ret == -EAGAIN &&
test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
!test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
/* Notify TCP that we're limited by the
* application window size.
*/
set_bit(SOCK_NOSPACE, &con->sock->flags);
con->sock->sk->sk_write_pending++;
}
cond_resched();
goto out;
} else if (ret < 0)
goto send_error;
}
/* Don't starve people filling buffers */
if (++count >= MAX_SEND_MSG_COUNT) {
cond_resched();
count = 0;
}
spin_lock(&con->writequeue_lock);
writequeue_entry_complete(e, ret);
}
spin_unlock(&con->writequeue_lock);
out:
mutex_unlock(&con->sock_mutex);
return;
send_error:
mutex_unlock(&con->sock_mutex);
close_connection(con, false, false, true);
/* Requeue the send work. When the work daemon runs again, it will try
a new connection, then call this function again. */
queue_work(send_workqueue, &con->swork);
return;
out_connect:
mutex_unlock(&con->sock_mutex);
queue_work(send_workqueue, &con->swork);
cond_resched();
}
static void clean_one_writequeue(struct connection *con)
{
struct writequeue_entry *e, *safe;
spin_lock(&con->writequeue_lock);
list_for_each_entry_safe(e, safe, &con->writequeue, list) {
list_del(&e->list);
free_entry(e);
}
spin_unlock(&con->writequeue_lock);
}
/* Called from recovery when it knows that a node has
left the cluster */
int dlm_lowcomms_close(int nodeid)
{
struct connection *con;
struct dlm_node_addr *na;
log_print("closing connection to node %d", nodeid);
con = nodeid2con(nodeid, 0);
if (con) {
set_bit(CF_CLOSE, &con->flags);
close_connection(con, true, true, true);
clean_one_writequeue(con);
if (con->othercon)
clean_one_writequeue(con->othercon);
}
spin_lock(&dlm_node_addrs_spin);
na = find_node_addr(nodeid);
if (na) {
list_del(&na->list);
while (na->addr_count--)
kfree(na->addr[na->addr_count]);
kfree(na);
}
spin_unlock(&dlm_node_addrs_spin);
return 0;
}
/* Receive workqueue function */
static void process_recv_sockets(struct work_struct *work)
{
struct connection *con = container_of(work, struct connection, rwork);
int err;
clear_bit(CF_READ_PENDING, &con->flags);
do {
err = receive_from_sock(con);
} while (!err);
}
static void process_listen_recv_socket(struct work_struct *work)
{
accept_from_sock(&listen_con);
}
/* Send workqueue function */
static void process_send_sockets(struct work_struct *work)
{
struct connection *con = container_of(work, struct connection, swork);
clear_bit(CF_WRITE_PENDING, &con->flags);
if (con->sock == NULL) /* not mutex protected so check it inside too */
con->connect_action(con);
if (!list_empty(&con->writequeue))
send_to_sock(con);
}
static void work_stop(void)
{
if (recv_workqueue)
destroy_workqueue(recv_workqueue);
if (send_workqueue)
destroy_workqueue(send_workqueue);
}
static int work_start(void)
{
recv_workqueue = alloc_workqueue("dlm_recv",
WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
if (!recv_workqueue) {
log_print("can't start dlm_recv");
return -ENOMEM;
}
send_workqueue = alloc_workqueue("dlm_send",
WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
if (!send_workqueue) {
log_print("can't start dlm_send");
destroy_workqueue(recv_workqueue);
return -ENOMEM;
}
return 0;
}
static void _stop_conn(struct connection *con, bool and_other)
{
mutex_lock(&con->sock_mutex);
set_bit(CF_CLOSE, &con->flags);
set_bit(CF_READ_PENDING, &con->flags);
set_bit(CF_WRITE_PENDING, &con->flags);
if (con->sock && con->sock->sk) {
write_lock_bh(&con->sock->sk->sk_callback_lock);
con->sock->sk->sk_user_data = NULL;
write_unlock_bh(&con->sock->sk->sk_callback_lock);
}
if (con->othercon && and_other)
_stop_conn(con->othercon, false);
mutex_unlock(&con->sock_mutex);
}
static void stop_conn(struct connection *con)
{
_stop_conn(con, true);
}
static void shutdown_conn(struct connection *con)
{
if (con->shutdown_action)
con->shutdown_action(con);
}
static void connection_release(struct rcu_head *rcu)
{
struct connection *con = container_of(rcu, struct connection, rcu);
kfree(con->rx_buf);
kfree(con);
}
static void free_conn(struct connection *con)
{
close_connection(con, true, true, true);
spin_lock(&connections_lock);
hlist_del_rcu(&con->list);
spin_unlock(&connections_lock);
if (con->othercon) {
clean_one_writequeue(con->othercon);
call_srcu(&connections_srcu, &con->othercon->rcu,
connection_release);
}
clean_one_writequeue(con);
call_srcu(&connections_srcu, &con->rcu, connection_release);
}
static void work_flush(void)
{
int ok, idx;
int i;
struct connection *con;
do {
ok = 1;
foreach_conn(stop_conn);
if (recv_workqueue)
flush_workqueue(recv_workqueue);
if (send_workqueue)
flush_workqueue(send_workqueue);
idx = srcu_read_lock(&connections_srcu);
for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
hlist_for_each_entry_rcu(con, &connection_hash[i],
list) {
ok &= test_bit(CF_READ_PENDING, &con->flags);
ok &= test_bit(CF_WRITE_PENDING, &con->flags);
if (con->othercon) {
ok &= test_bit(CF_READ_PENDING,
&con->othercon->flags);
ok &= test_bit(CF_WRITE_PENDING,
&con->othercon->flags);
}
}
}
srcu_read_unlock(&connections_srcu, idx);
} while (!ok);
}
void dlm_lowcomms_stop(void)
{
/* Set all the flags to prevent any
socket activity.
*/
dlm_allow_conn = 0;
if (recv_workqueue)
flush_workqueue(recv_workqueue);
if (send_workqueue)
flush_workqueue(send_workqueue);
dlm_close_sock(&listen_con.sock);
foreach_conn(shutdown_conn);
work_flush();
foreach_conn(free_conn);
work_stop();
deinit_local();
}
int dlm_lowcomms_start(void)
{
int error = -EINVAL;
int i;
for (i = 0; i < CONN_HASH_SIZE; i++)
INIT_HLIST_HEAD(&connection_hash[i]);
init_local();
if (!dlm_local_count) {
error = -ENOTCONN;
log_print("no local IP address has been set");
goto fail;
}
INIT_WORK(&listen_con.rwork, process_listen_recv_socket);
error = work_start();
if (error)
goto fail;
dlm_allow_conn = 1;
/* Start listening */
if (dlm_config.ci_protocol == 0)
error = tcp_listen_for_all();
else
error = sctp_listen_for_all(&listen_con);
if (error)
goto fail_unlisten;
return 0;
fail_unlisten:
dlm_allow_conn = 0;
dlm_close_sock(&listen_con.sock);
fail:
return error;
}
void dlm_lowcomms_exit(void)
{
struct dlm_node_addr *na, *safe;
spin_lock(&dlm_node_addrs_spin);
list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
list_del(&na->list);
while (na->addr_count--)
kfree(na->addr[na->addr_count]);
kfree(na);
}
spin_unlock(&dlm_node_addrs_spin);
}
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