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/*
* llc_station.c - station component of LLC
*
* Copyright (c) 1997 by Procom Technology, Inc.
* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program can be redistributed or modified under the terms of the
* GNU General Public License as published by the Free Software Foundation.
* This program is distributed without any warranty or implied warranty
* of merchantability or fitness for a particular purpose.
*
* See the GNU General Public License for more details.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <net/llc.h>
#include <net/llc_sap.h>
#include <net/llc_conn.h>
#include <net/llc_c_ac.h>
#include <net/llc_s_ac.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_st.h>
#include <net/llc_s_ev.h>
#include <net/llc_s_st.h>
#include <net/llc_pdu.h>
typedef int (*llc_station_ev_t)(struct sk_buff *skb);
typedef int (*llc_station_action_t)(struct sk_buff *skb);
/* Station component state table structure */
struct llc_station_state_trans {
llc_station_ev_t ev;
llc_station_action_t *ev_actions;
};
static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return LLC_PDU_IS_CMD(pdu) && /* command PDU */
LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_XID &&
!pdu->dsap ? 0 : 1; /* NULL DSAP value */
}
static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
{
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return LLC_PDU_IS_CMD(pdu) && /* command PDU */
LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
LLC_U_PDU_CMD(pdu) == LLC_1_PDU_CMD_TEST &&
!pdu->dsap ? 0 : 1; /* NULL DSAP */
}
static int llc_station_ac_send_xid_r(struct sk_buff *skb)
{
u8 mac_da[ETH_ALEN], dsap;
int rc = 1;
struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U,
sizeof(struct llc_xid_info));
if (!nskb)
goto out;
rc = 0;
llc_pdu_decode_sa(skb, mac_da);
llc_pdu_decode_ssap(skb, &dsap);
llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
llc_pdu_init_as_xid_rsp(nskb, LLC_XID_NULL_CLASS_2, 127);
rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
if (unlikely(rc))
goto free;
dev_queue_xmit(nskb);
out:
return rc;
free:
kfree_skb(nskb);
goto out;
}
static int llc_station_ac_send_test_r(struct sk_buff *skb)
{
u8 mac_da[ETH_ALEN], dsap;
int rc = 1;
u32 data_size;
struct sk_buff *nskb;
/* The test request command is type U (llc_len = 3) */
data_size = ntohs(eth_hdr(skb)->h_proto) - 3;
nskb = llc_alloc_frame(NULL, skb->dev, LLC_PDU_TYPE_U, data_size);
if (!nskb)
goto out;
rc = 0;
llc_pdu_decode_sa(skb, mac_da);
llc_pdu_decode_ssap(skb, &dsap);
llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, dsap, LLC_PDU_RSP);
llc_pdu_init_as_test_rsp(nskb, skb);
rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, mac_da);
if (unlikely(rc))
goto free;
dev_queue_xmit(nskb);
out:
return rc;
free:
kfree_skb(nskb);
goto out;
}
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
static llc_station_action_t llc_stat_up_state_actions_2[] = {
llc_station_ac_send_xid_r,
NULL,
};
static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
.ev = llc_stat_ev_rx_null_dsap_xid_c,
.ev_actions = llc_stat_up_state_actions_2,
};
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_TEST_C event */
static llc_station_action_t llc_stat_up_state_actions_3[] = {
llc_station_ac_send_test_r,
NULL,
};
static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
.ev = llc_stat_ev_rx_null_dsap_test_c,
.ev_actions = llc_stat_up_state_actions_3,
};
/* array of pointers; one to each transition */
static struct llc_station_state_trans *llc_stat_up_state_trans [] = {
&llc_stat_up_state_trans_2,
&llc_stat_up_state_trans_3,
NULL,
};
/**
* llc_exec_station_trans_actions - executes actions for transition
* @trans: Address of the transition
* @skb: Address of the event that caused the transition
*
* Executes actions of a transition of the station state machine. Returns
* 0 if all actions complete successfully, nonzero otherwise.
*/
static u16 llc_exec_station_trans_actions(struct llc_station_state_trans *trans,
struct sk_buff *skb)
{
u16 rc = 0;
llc_station_action_t *next_action = trans->ev_actions;
for (; next_action && *next_action; next_action++)
if ((*next_action)(skb))
rc = 1;
return rc;
}
/**
* llc_find_station_trans - finds transition for this event
* @skb: Address of the event
*
* Search thru events of the current state of the station until list
* exhausted or it's obvious that the event is not valid for the current
* state. Returns the address of the transition if cound, %NULL otherwise.
*/
static struct llc_station_state_trans *
llc_find_station_trans(struct sk_buff *skb)
{
int i = 0;
struct llc_station_state_trans *rc = NULL;
struct llc_station_state_trans **next_trans;
for (next_trans = llc_stat_up_state_trans; next_trans[i]; i++)
if (!next_trans[i]->ev(skb)) {
rc = next_trans[i];
break;
}
return rc;
}
/**
* llc_station_rcv - send received pdu to the station state machine
* @skb: received frame.
*
* Sends data unit to station state machine.
*/
static void llc_station_rcv(struct sk_buff *skb)
{
struct llc_station_state_trans *trans;
trans = llc_find_station_trans(skb);
if (trans)
llc_exec_station_trans_actions(trans, skb);
kfree_skb(skb);
}
void __init llc_station_init(void)
{
llc_set_station_handler(llc_station_rcv);
}
void llc_station_exit(void)
{
llc_set_station_handler(NULL);
}
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