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linux/net/lapb/lapb_iface.c
Wang Hai e83332842a net: lapb: Use list_for_each_entry() to simplify code in lapb_iface.c 
Convert list_for_each() to list_for_each_entry() where
applicable. This simplifies the code.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-08 16:31:25 -07:00

553 lines
11 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* LAPB release 002
*
* This code REQUIRES 2.1.15 or higher/ NET3.038
*
* History
* LAPB 001 Jonathan Naylor Started Coding
* LAPB 002 Jonathan Naylor New timer architecture.
* 2000-10-29 Henner Eisen lapb_data_indication() return status.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <net/lapb.h>
static LIST_HEAD(lapb_list);
static DEFINE_RWLOCK(lapb_list_lock);
/*
* Free an allocated lapb control block.
*/
static void lapb_free_cb(struct lapb_cb *lapb)
{
kfree(lapb);
}
static __inline__ void lapb_hold(struct lapb_cb *lapb)
{
refcount_inc(&lapb->refcnt);
}
static __inline__ void lapb_put(struct lapb_cb *lapb)
{
if (refcount_dec_and_test(&lapb->refcnt))
lapb_free_cb(lapb);
}
/*
* Socket removal during an interrupt is now safe.
*/
static void __lapb_remove_cb(struct lapb_cb *lapb)
{
if (lapb->node.next) {
list_del(&lapb->node);
lapb_put(lapb);
}
}
/*
* Add a socket to the bound sockets list.
*/
static void __lapb_insert_cb(struct lapb_cb *lapb)
{
list_add(&lapb->node, &lapb_list);
lapb_hold(lapb);
}
static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
{
struct lapb_cb *lapb, *use = NULL;
list_for_each_entry(lapb, &lapb_list, node) {
if (lapb->dev == dev) {
use = lapb;
break;
}
}
if (use)
lapb_hold(use);
return use;
}
static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
{
struct lapb_cb *rc;
read_lock_bh(&lapb_list_lock);
rc = __lapb_devtostruct(dev);
read_unlock_bh(&lapb_list_lock);
return rc;
}
/*
* Create an empty LAPB control block.
*/
static struct lapb_cb *lapb_create_cb(void)
{
struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
if (!lapb)
goto out;
skb_queue_head_init(&lapb->write_queue);
skb_queue_head_init(&lapb->ack_queue);
timer_setup(&lapb->t1timer, NULL, 0);
timer_setup(&lapb->t2timer, NULL, 0);
lapb->t1timer_running = false;
lapb->t2timer_running = false;
lapb->t1 = LAPB_DEFAULT_T1;
lapb->t2 = LAPB_DEFAULT_T2;
lapb->n2 = LAPB_DEFAULT_N2;
lapb->mode = LAPB_DEFAULT_MODE;
lapb->window = LAPB_DEFAULT_WINDOW;
lapb->state = LAPB_STATE_0;
spin_lock_init(&lapb->lock);
refcount_set(&lapb->refcnt, 1);
out:
return lapb;
}
int lapb_register(struct net_device *dev,
const struct lapb_register_struct *callbacks)
{
struct lapb_cb *lapb;
int rc = LAPB_BADTOKEN;
write_lock_bh(&lapb_list_lock);
lapb = __lapb_devtostruct(dev);
if (lapb) {
lapb_put(lapb);
goto out;
}
lapb = lapb_create_cb();
rc = LAPB_NOMEM;
if (!lapb)
goto out;
lapb->dev = dev;
lapb->callbacks = callbacks;
__lapb_insert_cb(lapb);
lapb_start_t1timer(lapb);
rc = LAPB_OK;
out:
write_unlock_bh(&lapb_list_lock);
return rc;
}
EXPORT_SYMBOL(lapb_register);
int lapb_unregister(struct net_device *dev)
{
struct lapb_cb *lapb;
int rc = LAPB_BADTOKEN;
write_lock_bh(&lapb_list_lock);
lapb = __lapb_devtostruct(dev);
if (!lapb)
goto out;
lapb_put(lapb);
/* Wait for other refs to "lapb" to drop */
while (refcount_read(&lapb->refcnt) > 2)
usleep_range(1, 10);
spin_lock_bh(&lapb->lock);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb_clear_queues(lapb);
spin_unlock_bh(&lapb->lock);
/* Wait for running timers to stop */
del_timer_sync(&lapb->t1timer);
del_timer_sync(&lapb->t2timer);
__lapb_remove_cb(lapb);
lapb_put(lapb);
rc = LAPB_OK;
out:
write_unlock_bh(&lapb_list_lock);
return rc;
}
EXPORT_SYMBOL(lapb_unregister);
int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
{
int rc = LAPB_BADTOKEN;
struct lapb_cb *lapb = lapb_devtostruct(dev);
if (!lapb)
goto out;
spin_lock_bh(&lapb->lock);
parms->t1 = lapb->t1 / HZ;
parms->t2 = lapb->t2 / HZ;
parms->n2 = lapb->n2;
parms->n2count = lapb->n2count;
parms->state = lapb->state;
parms->window = lapb->window;
parms->mode = lapb->mode;
if (!timer_pending(&lapb->t1timer))
parms->t1timer = 0;
else
parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
if (!timer_pending(&lapb->t2timer))
parms->t2timer = 0;
else
parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
spin_unlock_bh(&lapb->lock);
lapb_put(lapb);
rc = LAPB_OK;
out:
return rc;
}
EXPORT_SYMBOL(lapb_getparms);
int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
{
int rc = LAPB_BADTOKEN;
struct lapb_cb *lapb = lapb_devtostruct(dev);
if (!lapb)
goto out;
spin_lock_bh(&lapb->lock);
rc = LAPB_INVALUE;
if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
goto out_put;
if (lapb->state == LAPB_STATE_0) {
if (parms->mode & LAPB_EXTENDED) {
if (parms->window < 1 || parms->window > 127)
goto out_put;
} else {
if (parms->window < 1 || parms->window > 7)
goto out_put;
}
lapb->mode = parms->mode;
lapb->window = parms->window;
}
lapb->t1 = parms->t1 * HZ;
lapb->t2 = parms->t2 * HZ;
lapb->n2 = parms->n2;
rc = LAPB_OK;
out_put:
spin_unlock_bh(&lapb->lock);
lapb_put(lapb);
out:
return rc;
}
EXPORT_SYMBOL(lapb_setparms);
int lapb_connect_request(struct net_device *dev)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (!lapb)
goto out;
spin_lock_bh(&lapb->lock);
rc = LAPB_OK;
if (lapb->state == LAPB_STATE_1)
goto out_put;
rc = LAPB_CONNECTED;
if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
goto out_put;
lapb_establish_data_link(lapb);
lapb_dbg(0, "(%p) S0 -> S1\n", lapb->dev);
lapb->state = LAPB_STATE_1;
rc = LAPB_OK;
out_put:
spin_unlock_bh(&lapb->lock);
lapb_put(lapb);
out:
return rc;
}
EXPORT_SYMBOL(lapb_connect_request);
static int __lapb_disconnect_request(struct lapb_cb *lapb)
{
switch (lapb->state) {
case LAPB_STATE_0:
return LAPB_NOTCONNECTED;
case LAPB_STATE_1:
lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev);
lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
return LAPB_NOTCONNECTED;
case LAPB_STATE_2:
return LAPB_OK;
}
lapb_clear_queues(lapb);
lapb->n2count = 0;
lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_2;
lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev);
lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev);
return LAPB_OK;
}
int lapb_disconnect_request(struct net_device *dev)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (!lapb)
goto out;
spin_lock_bh(&lapb->lock);
rc = __lapb_disconnect_request(lapb);
spin_unlock_bh(&lapb->lock);
lapb_put(lapb);
out:
return rc;
}
EXPORT_SYMBOL(lapb_disconnect_request);
int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (!lapb)
goto out;
spin_lock_bh(&lapb->lock);
rc = LAPB_NOTCONNECTED;
if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
goto out_put;
skb_queue_tail(&lapb->write_queue, skb);
lapb_kick(lapb);
rc = LAPB_OK;
out_put:
spin_unlock_bh(&lapb->lock);
lapb_put(lapb);
out:
return rc;
}
EXPORT_SYMBOL(lapb_data_request);
int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (lapb) {
spin_lock_bh(&lapb->lock);
lapb_data_input(lapb, skb);
spin_unlock_bh(&lapb->lock);
lapb_put(lapb);
rc = LAPB_OK;
}
return rc;
}
EXPORT_SYMBOL(lapb_data_received);
void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks->connect_confirmation)
lapb->callbacks->connect_confirmation(lapb->dev, reason);
}
void lapb_connect_indication(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks->connect_indication)
lapb->callbacks->connect_indication(lapb->dev, reason);
}
void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks->disconnect_confirmation)
lapb->callbacks->disconnect_confirmation(lapb->dev, reason);
}
void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks->disconnect_indication)
lapb->callbacks->disconnect_indication(lapb->dev, reason);
}
int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
{
if (lapb->callbacks->data_indication)
return lapb->callbacks->data_indication(lapb->dev, skb);
kfree_skb(skb);
return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */
}
int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
{
int used = 0;
if (lapb->callbacks->data_transmit) {
lapb->callbacks->data_transmit(lapb->dev, skb);
used = 1;
}
return used;
}
/* Handle device status changes. */
static int lapb_device_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct lapb_cb *lapb;
if (!net_eq(dev_net(dev), &init_net))
return NOTIFY_DONE;
if (dev->type != ARPHRD_X25)
return NOTIFY_DONE;
lapb = lapb_devtostruct(dev);
if (!lapb)
return NOTIFY_DONE;
spin_lock_bh(&lapb->lock);
switch (event) {
case NETDEV_UP:
lapb_dbg(0, "(%p) Interface up: %s\n", dev, dev->name);
if (netif_carrier_ok(dev)) {
lapb_dbg(0, "(%p): Carrier is already up: %s\n", dev,
dev->name);
if (lapb->mode & LAPB_DCE) {
lapb_start_t1timer(lapb);
} else {
if (lapb->state == LAPB_STATE_0) {
lapb->state = LAPB_STATE_1;
lapb_establish_data_link(lapb);
}
}
}
break;
case NETDEV_GOING_DOWN:
if (netif_carrier_ok(dev))
__lapb_disconnect_request(lapb);
break;
case NETDEV_DOWN:
lapb_dbg(0, "(%p) Interface down: %s\n", dev, dev->name);
lapb_dbg(0, "(%p) S%d -> S0\n", dev, lapb->state);
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb->n2count = 0;
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
break;
case NETDEV_CHANGE:
if (netif_carrier_ok(dev)) {
lapb_dbg(0, "(%p): Carrier detected: %s\n", dev,
dev->name);
if (lapb->mode & LAPB_DCE) {
lapb_start_t1timer(lapb);
} else {
if (lapb->state == LAPB_STATE_0) {
lapb->state = LAPB_STATE_1;
lapb_establish_data_link(lapb);
}
}
} else {
lapb_dbg(0, "(%p) Carrier lost: %s\n", dev, dev->name);
lapb_dbg(0, "(%p) S%d -> S0\n", dev, lapb->state);
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb->n2count = 0;
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
}
break;
}
spin_unlock_bh(&lapb->lock);
lapb_put(lapb);
return NOTIFY_DONE;
}
static struct notifier_block lapb_dev_notifier = {
.notifier_call = lapb_device_event,
};
static int __init lapb_init(void)
{
return register_netdevice_notifier(&lapb_dev_notifier);
}
static void __exit lapb_exit(void)
{
WARN_ON(!list_empty(&lapb_list));
unregister_netdevice_notifier(&lapb_dev_notifier);
}
MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
MODULE_LICENSE("GPL");
module_init(lapb_init);
module_exit(lapb_exit);
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