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// SPDX-License-Identifier: GPL-2.0
/*
* llc_core.c - Minimum needed routines for sap handling and module init/exit
*
* Copyright (c) 1997 by Procom Technology, Inc.
* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*/
#include <linux/module.h>
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <net/llc.h>
static LIST_HEAD(llc_sap_list);
static DEFINE_SPINLOCK(llc_sap_list_lock);
/**
* llc_sap_alloc - allocates and initializes sap.
*
* Allocates and initializes sap.
*/
static struct llc_sap *llc_sap_alloc(void)
{
struct llc_sap *sap = kzalloc_obj(*sap, GFP_ATOMIC);
if (sap)
refcount_set(&sap->refcnt, 1);
return sap;
}
static struct llc_sap *__llc_sap_find(unsigned char sap_value)
{
struct llc_sap *sap;
list_for_each_entry(sap, &llc_sap_list, node)
if (sap->lsap == sap_value)
goto out;
sap = NULL;
out:
return sap;
}
/**
* llc_sap_find - searches for a SAP by its number
* @sap_value: sap to be found
*
* If the sap is found it will be refcounted and the user will have to do
* a llc_sap_put after use.
* Returns the sap or %NULL if not found.
*/
struct llc_sap *llc_sap_find(unsigned char sap_value)
{
struct llc_sap *sap;
rcu_read_lock_bh();
sap = __llc_sap_find(sap_value);
if (!sap || !llc_sap_hold_safe(sap))
sap = NULL;
rcu_read_unlock_bh();
return sap;
}
/**
* llc_sap_open - open interface to the upper layers.
* @lsap: SAP number.
* @func: rcv func for datalink protos
*
* Interface function to upper layer. Each one who wants to get a SAP
* (for example NetBEUI) should call this function. Returns the opened
* SAP for success, NULL for failure.
*/
struct llc_sap *llc_sap_open(unsigned char lsap,
int (*func)(struct sk_buff *skb,
struct net_device *dev,
struct packet_type *pt,
struct net_device *orig_dev))
{
struct llc_sap *sap = NULL;
spin_lock_bh(&llc_sap_list_lock);
if (__llc_sap_find(lsap)) /* SAP already exists */
goto out;
sap = llc_sap_alloc();
if (!sap)
goto out;
sap->lsap = lsap;
sap->rcv_func = func;
list_add_tail_rcu(&sap->node, &llc_sap_list);
out:
spin_unlock_bh(&llc_sap_list_lock);
return sap;
}
/**
* llc_sap_close - close interface for upper layers.
* @sap: SAP to be closed.
*
* Close interface function to upper layer. Each one who wants to
* close an open SAP (for example NetBEUI) should call this function.
* Removes this sap from the SAP list and then frees the memory for it.
*/
void llc_sap_close(struct llc_sap *sap)
{
spin_lock_bh(&llc_sap_list_lock);
list_del_rcu(&sap->node);
spin_unlock_bh(&llc_sap_list_lock);
kfree_rcu(sap, rcu);
}
static struct packet_type llc_packet_type __read_mostly = {
.type = cpu_to_be16(ETH_P_802_2),
.func = llc_rcv,
};
static int __init llc_init(void)
{
dev_add_pack(&llc_packet_type);
return 0;
}
static void __exit llc_exit(void)
{
dev_remove_pack(&llc_packet_type);
}
module_init(llc_init);
module_exit(llc_exit);
EXPORT_SYMBOL(llc_sap_open);
EXPORT_SYMBOL(llc_sap_close);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
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