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