linux/fs/ocfs2/cluster/tcp.h
Gustavo A. R. Silva fa803cf8f3 ocfs2: cluster: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied.  As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://urldefense.com/v3/__https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html__;!!GqivPVa7Brio!NzMr-YRl2zy-K3lwLVVatz7x0uD2z7-ykQag4GrGigxmfWU8TWzDy6xrkTiW3hYl00czlw$
[2] https://urldefense.com/v3/__https://github.com/KSPP/linux/issues/21__;!!GqivPVa7Brio!NzMr-YRl2zy-K3lwLVVatz7x0uD2z7-ykQag4GrGigxmfWU8TWzDy6xrkTiW3hYHG1nAnw$
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Link: http://lkml.kernel.org/r/20200309201907.GA8005@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02 09:35:25 -07:00

140 lines
3.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* tcp.h
*
* Function prototypes
*
* Copyright (C) 2004 Oracle. All rights reserved.
*/
#ifndef O2CLUSTER_TCP_H
#define O2CLUSTER_TCP_H
#include <linux/socket.h>
#ifdef __KERNEL__
#include <net/sock.h>
#include <linux/tcp.h>
#else
#include <sys/socket.h>
#endif
#include <linux/inet.h>
#include <linux/in.h>
struct o2net_msg
{
__be16 magic;
__be16 data_len;
__be16 msg_type;
__be16 pad1;
__be32 sys_status;
__be32 status;
__be32 key;
__be32 msg_num;
__u8 buf[];
};
typedef int (o2net_msg_handler_func)(struct o2net_msg *msg, u32 len, void *data,
void **ret_data);
typedef void (o2net_post_msg_handler_func)(int status, void *data,
void *ret_data);
#define O2NET_MAX_PAYLOAD_BYTES (4096 - sizeof(struct o2net_msg))
/* same as hb delay, we're waiting for another node to recognize our hb */
#define O2NET_RECONNECT_DELAY_MS_DEFAULT 2000
#define O2NET_KEEPALIVE_DELAY_MS_DEFAULT 2000
#define O2NET_IDLE_TIMEOUT_MS_DEFAULT 30000
#define O2NET_TCP_USER_TIMEOUT 0x7fffffff
/* TODO: figure this out.... */
static inline int o2net_link_down(int err, struct socket *sock)
{
if (sock) {
if (sock->sk->sk_state != TCP_ESTABLISHED &&
sock->sk->sk_state != TCP_CLOSE_WAIT)
return 1;
}
if (err >= 0)
return 0;
switch (err) {
/* ????????????????????????? */
case -ERESTARTSYS:
case -EBADF:
/* When the server has died, an ICMP port unreachable
* message prompts ECONNREFUSED. */
case -ECONNREFUSED:
case -ENOTCONN:
case -ECONNRESET:
case -EPIPE:
return 1;
}
return 0;
}
enum {
O2NET_DRIVER_UNINITED,
O2NET_DRIVER_READY,
};
int o2net_send_message(u32 msg_type, u32 key, void *data, u32 len,
u8 target_node, int *status);
int o2net_send_message_vec(u32 msg_type, u32 key, struct kvec *vec,
size_t veclen, u8 target_node, int *status);
int o2net_register_handler(u32 msg_type, u32 key, u32 max_len,
o2net_msg_handler_func *func, void *data,
o2net_post_msg_handler_func *post_func,
struct list_head *unreg_list);
void o2net_unregister_handler_list(struct list_head *list);
void o2net_fill_node_map(unsigned long *map, unsigned bytes);
struct o2nm_node;
int o2net_register_hb_callbacks(void);
void o2net_unregister_hb_callbacks(void);
int o2net_start_listening(struct o2nm_node *node);
void o2net_stop_listening(struct o2nm_node *node);
void o2net_disconnect_node(struct o2nm_node *node);
int o2net_num_connected_peers(void);
int o2net_init(void);
void o2net_exit(void);
struct o2net_send_tracking;
struct o2net_sock_container;
#ifdef CONFIG_DEBUG_FS
void o2net_debugfs_init(void);
void o2net_debugfs_exit(void);
void o2net_debug_add_nst(struct o2net_send_tracking *nst);
void o2net_debug_del_nst(struct o2net_send_tracking *nst);
void o2net_debug_add_sc(struct o2net_sock_container *sc);
void o2net_debug_del_sc(struct o2net_sock_container *sc);
#else
static inline void o2net_debugfs_init(void)
{
}
static inline void o2net_debugfs_exit(void)
{
}
static inline void o2net_debug_add_nst(struct o2net_send_tracking *nst)
{
}
static inline void o2net_debug_del_nst(struct o2net_send_tracking *nst)
{
}
static inline void o2net_debug_add_sc(struct o2net_sock_container *sc)
{
}
static inline void o2net_debug_del_sc(struct o2net_sock_container *sc)
{
}
#endif /* CONFIG_DEBUG_FS */
#endif /* O2CLUSTER_TCP_H */