160 lines
3.9 KiB
C
160 lines
3.9 KiB
C
/*
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* llc_core.c - Minimum needed routines for sap handling and module init/exit
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*
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* Copyright (c) 1997 by Procom Technology, Inc.
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* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program can be redistributed or modified under the terms of the
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* GNU General Public License as published by the Free Software Foundation.
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* This program is distributed without any warranty or implied warranty
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* of merchantability or fitness for a particular purpose.
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*
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* See the GNU General Public License for more details.
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*/
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/if_ether.h>
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#include <linux/netdevice.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/init.h>
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#include <net/net_namespace.h>
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#include <net/llc.h>
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LIST_HEAD(llc_sap_list);
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static DEFINE_SPINLOCK(llc_sap_list_lock);
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/**
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* llc_sap_alloc - allocates and initializes sap.
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*
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* Allocates and initializes sap.
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*/
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static struct llc_sap *llc_sap_alloc(void)
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{
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struct llc_sap *sap = kzalloc(sizeof(*sap), GFP_ATOMIC);
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int i;
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if (sap) {
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/* sap->laddr.mac - leave as a null, it's filled by bind */
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sap->state = LLC_SAP_STATE_ACTIVE;
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spin_lock_init(&sap->sk_lock);
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for (i = 0; i < LLC_SK_LADDR_HASH_ENTRIES; i++)
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INIT_HLIST_NULLS_HEAD(&sap->sk_laddr_hash[i], i);
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refcount_set(&sap->refcnt, 1);
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}
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return sap;
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}
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static struct llc_sap *__llc_sap_find(unsigned char sap_value)
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{
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struct llc_sap *sap;
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list_for_each_entry(sap, &llc_sap_list, node)
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if (sap->laddr.lsap == sap_value)
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goto out;
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sap = NULL;
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out:
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return sap;
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}
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/**
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* llc_sap_find - searches a SAP in station
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* @sap_value: sap to be found
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*
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* Searches for a sap in the sap list of the LLC's station upon the sap ID.
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* If the sap is found it will be refcounted and the user will have to do
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* a llc_sap_put after use.
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* Returns the sap or %NULL if not found.
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*/
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struct llc_sap *llc_sap_find(unsigned char sap_value)
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{
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struct llc_sap *sap;
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rcu_read_lock_bh();
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sap = __llc_sap_find(sap_value);
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if (!sap || !llc_sap_hold_safe(sap))
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sap = NULL;
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rcu_read_unlock_bh();
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return sap;
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}
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/**
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* llc_sap_open - open interface to the upper layers.
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* @lsap: SAP number.
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* @func: rcv func for datalink protos
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*
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* Interface function to upper layer. Each one who wants to get a SAP
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* (for example NetBEUI) should call this function. Returns the opened
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* SAP for success, NULL for failure.
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*/
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struct llc_sap *llc_sap_open(unsigned char lsap,
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int (*func)(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt,
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struct net_device *orig_dev))
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{
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struct llc_sap *sap = NULL;
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spin_lock_bh(&llc_sap_list_lock);
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if (__llc_sap_find(lsap)) /* SAP already exists */
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goto out;
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sap = llc_sap_alloc();
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if (!sap)
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goto out;
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sap->laddr.lsap = lsap;
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sap->rcv_func = func;
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list_add_tail_rcu(&sap->node, &llc_sap_list);
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out:
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spin_unlock_bh(&llc_sap_list_lock);
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return sap;
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}
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/**
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* llc_sap_close - close interface for upper layers.
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* @sap: SAP to be closed.
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*
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* Close interface function to upper layer. Each one who wants to
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* close an open SAP (for example NetBEUI) should call this function.
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* Removes this sap from the list of saps in the station and then
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* frees the memory for this sap.
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*/
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void llc_sap_close(struct llc_sap *sap)
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{
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WARN_ON(sap->sk_count);
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spin_lock_bh(&llc_sap_list_lock);
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list_del_rcu(&sap->node);
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spin_unlock_bh(&llc_sap_list_lock);
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kfree_rcu(sap, rcu);
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}
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static struct packet_type llc_packet_type __read_mostly = {
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.type = cpu_to_be16(ETH_P_802_2),
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.func = llc_rcv,
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};
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static int __init llc_init(void)
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{
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dev_add_pack(&llc_packet_type);
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return 0;
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}
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static void __exit llc_exit(void)
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{
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dev_remove_pack(&llc_packet_type);
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}
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module_init(llc_init);
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module_exit(llc_exit);
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EXPORT_SYMBOL(llc_sap_list);
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EXPORT_SYMBOL(llc_sap_find);
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EXPORT_SYMBOL(llc_sap_open);
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EXPORT_SYMBOL(llc_sap_close);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
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MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
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