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DEFINITIONS
This source file includes following definitions.
- llc_station_ev
- llc_stat_ev_enable_with_dup_addr_check
- llc_stat_ev_enable_without_dup_addr_check
- llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry
- llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry
- llc_stat_ev_rx_null_dsap_xid_c
- llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq
- llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq
- llc_stat_ev_rx_null_dsap_test_c
- llc_stat_ev_disable_req
- llc_station_send_pdu
- llc_station_ac_start_ack_timer
- llc_station_ac_set_retry_cnt_0
- llc_station_ac_inc_retry_cnt_by_1
- llc_station_ac_set_xid_r_cnt_0
- llc_station_ac_inc_xid_r_cnt_by_1
- llc_station_ac_send_null_dsap_xid_c
- llc_station_ac_send_xid_r
- llc_station_ac_send_test_r
- llc_station_ac_report_status
- llc_exec_station_trans_actions
- llc_find_station_trans
- llc_station_free_ev
- llc_station_next_state
- llc_station_service_events
- llc_station_state_process
- llc_station_ack_tmr_cb
- llc_station_rcv
- llc_station_init
- llc_station_exit
/*
* 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 <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>
/**
* struct llc_station - LLC station component
*
* SAP and connection resource manager, one per adapter.
*
* @state - state of station
* @xid_r_count - XID response PDU counter
* @mac_sa - MAC source address
* @sap_list - list of related SAPs
* @ev_q - events entering state mach.
* @mac_pdu_q - PDUs ready to send to MAC
*/
struct llc_station {
u8 state;
u8 xid_r_count;
struct timer_list ack_timer;
u8 retry_count;
u8 maximum_retry;
struct {
struct sk_buff_head list;
spinlock_t lock;
} ev_q;
struct sk_buff_head mac_pdu_q;
};
#define LLC_STATION_ACK_TIME (3 * HZ)
int sysctl_llc_station_ack_timeout = LLC_STATION_ACK_TIME;
/* Types of events (possible values in 'ev->type') */
#define LLC_STATION_EV_TYPE_SIMPLE 1
#define LLC_STATION_EV_TYPE_CONDITION 2
#define LLC_STATION_EV_TYPE_PRIM 3
#define LLC_STATION_EV_TYPE_PDU 4 /* command/response PDU */
#define LLC_STATION_EV_TYPE_ACK_TMR 5
#define LLC_STATION_EV_TYPE_RPT_STATUS 6
/* Events */
#define LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK 1
#define LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK 2
#define LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY 3
#define LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY 4
#define LLC_STATION_EV_RX_NULL_DSAP_XID_C 5
#define LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ 6
#define LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ 7
#define LLC_STATION_EV_RX_NULL_DSAP_TEST_C 8
#define LLC_STATION_EV_DISABLE_REQ 9
struct llc_station_state_ev {
u8 type;
u8 prim;
u8 prim_type;
u8 reason;
struct list_head node; /* node in station->ev_q.list */
};
static __inline__ struct llc_station_state_ev *
llc_station_ev(struct sk_buff *skb)
{
return (struct llc_station_state_ev *)skb->cb;
}
typedef int (*llc_station_ev_t)(struct sk_buff *skb);
#define LLC_STATION_STATE_DOWN 1 /* initial state */
#define LLC_STATION_STATE_DUP_ADDR_CHK 2
#define LLC_STATION_STATE_UP 3
#define LLC_NBR_STATION_STATES 3 /* size of state table */
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;
u8 next_state;
llc_station_action_t *ev_actions;
};
struct llc_station_state {
u8 curr_state;
struct llc_station_state_trans **transitions;
};
static struct llc_station llc_main_station;
static int llc_stat_ev_enable_with_dup_addr_check(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
ev->prim_type ==
LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK ? 0 : 1;
}
static int llc_stat_ev_enable_without_dup_addr_check(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
return ev->type == LLC_STATION_EV_TYPE_SIMPLE &&
ev->prim_type ==
LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK ? 0 : 1;
}
static int llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
llc_main_station.retry_count <
llc_main_station.maximum_retry ? 0 : 1;
}
static int llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
return ev->type == LLC_STATION_EV_TYPE_ACK_TMR &&
llc_main_station.retry_count ==
llc_main_station.maximum_retry ? 0 : 1;
}
static int llc_stat_ev_rx_null_dsap_xid_c(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return ev->type == LLC_STATION_EV_TYPE_PDU &&
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_0_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return ev->type == LLC_STATION_EV_TYPE_PDU &&
LLC_PDU_IS_RSP(pdu) && /* response PDU */
LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
!pdu->dsap && /* NULL DSAP value */
!llc_main_station.xid_r_count ? 0 : 1;
}
static int llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return ev->type == LLC_STATION_EV_TYPE_PDU &&
LLC_PDU_IS_RSP(pdu) && /* response PDU */
LLC_PDU_TYPE_IS_U(pdu) && /* U type PDU */
LLC_U_PDU_RSP(pdu) == LLC_1_PDU_CMD_XID &&
!pdu->dsap && /* NULL DSAP value */
llc_main_station.xid_r_count == 1 ? 0 : 1;
}
static int llc_stat_ev_rx_null_dsap_test_c(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
return ev->type == LLC_STATION_EV_TYPE_PDU &&
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_stat_ev_disable_req(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
return ev->type == LLC_STATION_EV_TYPE_PRIM &&
ev->prim == LLC_DISABLE_PRIM &&
ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
}
/**
* llc_station_send_pdu - queues PDU to send
* @skb: Address of the PDU
*
* Queues a PDU to send to the MAC layer.
*/
static void llc_station_send_pdu(struct sk_buff *skb)
{
skb_queue_tail(&llc_main_station.mac_pdu_q, skb);
while ((skb = skb_dequeue(&llc_main_station.mac_pdu_q)) != NULL)
if (dev_queue_xmit(skb))
break;
}
static int llc_station_ac_start_ack_timer(struct sk_buff *skb)
{
mod_timer(&llc_main_station.ack_timer,
jiffies + sysctl_llc_station_ack_timeout);
return 0;
}
static int llc_station_ac_set_retry_cnt_0(struct sk_buff *skb)
{
llc_main_station.retry_count = 0;
return 0;
}
static int llc_station_ac_inc_retry_cnt_by_1(struct sk_buff *skb)
{
llc_main_station.retry_count++;
return 0;
}
static int llc_station_ac_set_xid_r_cnt_0(struct sk_buff *skb)
{
llc_main_station.xid_r_count = 0;
return 0;
}
static int llc_station_ac_inc_xid_r_cnt_by_1(struct sk_buff *skb)
{
llc_main_station.xid_r_count++;
return 0;
}
static int llc_station_ac_send_null_dsap_xid_c(struct sk_buff *skb)
{
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;
llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, 0, 0, LLC_PDU_CMD);
llc_pdu_init_as_xid_cmd(nskb, LLC_XID_NULL_CLASS_2, 127);
rc = llc_mac_hdr_init(nskb, skb->dev->dev_addr, skb->dev->dev_addr);
if (unlikely(rc))
goto free;
llc_station_send_pdu(nskb);
out:
return rc;
free:
kfree_skb(skb);
goto out;
}
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;
llc_station_send_pdu(nskb);
out:
return rc;
free:
kfree_skb(skb);
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;
llc_station_send_pdu(nskb);
out:
return rc;
free:
kfree_skb(skb);
goto out;
}
static int llc_station_ac_report_status(struct sk_buff *skb)
{
return 0;
}
/* COMMON STATION STATE transitions */
/* dummy last-transition indicator; common to all state transition groups
* last entry for this state
* all members are zeros, .bss zeroes it
*/
static struct llc_station_state_trans llc_stat_state_trans_end;
/* DOWN STATE transitions */
/* state transition for LLC_STATION_EV_ENABLE_WITH_DUP_ADDR_CHECK event */
static llc_station_action_t llc_stat_down_state_actions_1[] = {
[0] = llc_station_ac_start_ack_timer,
[1] = llc_station_ac_set_retry_cnt_0,
[2] = llc_station_ac_set_xid_r_cnt_0,
[3] = llc_station_ac_send_null_dsap_xid_c,
[4] = NULL,
};
static struct llc_station_state_trans llc_stat_down_state_trans_1 = {
.ev = llc_stat_ev_enable_with_dup_addr_check,
.next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
.ev_actions = llc_stat_down_state_actions_1,
};
/* state transition for LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK event */
static llc_station_action_t llc_stat_down_state_actions_2[] = {
[0] = llc_station_ac_report_status, /* STATION UP */
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_down_state_trans_2 = {
.ev = llc_stat_ev_enable_without_dup_addr_check,
.next_state = LLC_STATION_STATE_UP,
.ev_actions = llc_stat_down_state_actions_2,
};
/* array of pointers; one to each transition */
static struct llc_station_state_trans *llc_stat_dwn_state_trans[] = {
[0] = &llc_stat_down_state_trans_1,
[1] = &llc_stat_down_state_trans_2,
[2] = &llc_stat_state_trans_end,
};
/* UP STATE transitions */
/* state transition for LLC_STATION_EV_DISABLE_REQ event */
static llc_station_action_t llc_stat_up_state_actions_1[] = {
[0] = llc_station_ac_report_status, /* STATION DOWN */
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_up_state_trans_1 = {
.ev = llc_stat_ev_disable_req,
.next_state = LLC_STATION_STATE_DOWN,
.ev_actions = llc_stat_up_state_actions_1,
};
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
static llc_station_action_t llc_stat_up_state_actions_2[] = {
[0] = llc_station_ac_send_xid_r,
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_up_state_trans_2 = {
.ev = llc_stat_ev_rx_null_dsap_xid_c,
.next_state = LLC_STATION_STATE_UP,
.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[] = {
[0] = llc_station_ac_send_test_r,
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_up_state_trans_3 = {
.ev = llc_stat_ev_rx_null_dsap_test_c,
.next_state = LLC_STATION_STATE_UP,
.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 [] = {
[0] = &llc_stat_up_state_trans_1,
[1] = &llc_stat_up_state_trans_2,
[2] = &llc_stat_up_state_trans_3,
[3] = &llc_stat_state_trans_end,
};
/* DUP ADDR CHK STATE transitions */
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_0_XID_R_XID_R_CNT_EQ
* event
*/
static llc_station_action_t llc_stat_dupaddr_state_actions_1[] = {
[0] = llc_station_ac_inc_xid_r_cnt_by_1,
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_dupaddr_state_trans_1 = {
.ev = llc_stat_ev_rx_null_dsap_0_xid_r_xid_r_cnt_eq,
.next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
.ev_actions = llc_stat_dupaddr_state_actions_1,
};
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_1_XID_R_XID_R_CNT_EQ
* event
*/
static llc_station_action_t llc_stat_dupaddr_state_actions_2[] = {
[0] = llc_station_ac_report_status, /* DUPLICATE ADDRESS FOUND */
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_dupaddr_state_trans_2 = {
.ev = llc_stat_ev_rx_null_dsap_1_xid_r_xid_r_cnt_eq,
.next_state = LLC_STATION_STATE_DOWN,
.ev_actions = llc_stat_dupaddr_state_actions_2,
};
/* state transition for LLC_STATION_EV_RX_NULL_DSAP_XID_C event */
static llc_station_action_t llc_stat_dupaddr_state_actions_3[] = {
[0] = llc_station_ac_send_xid_r,
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_dupaddr_state_trans_3 = {
.ev = llc_stat_ev_rx_null_dsap_xid_c,
.next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
.ev_actions = llc_stat_dupaddr_state_actions_3,
};
/* state transition for LLC_STATION_EV_ACK_TMR_EXP_LT_RETRY_CNT_MAX_RETRY
* event
*/
static llc_station_action_t llc_stat_dupaddr_state_actions_4[] = {
[0] = llc_station_ac_start_ack_timer,
[1] = llc_station_ac_inc_retry_cnt_by_1,
[2] = llc_station_ac_set_xid_r_cnt_0,
[3] = llc_station_ac_send_null_dsap_xid_c,
[4] = NULL,
};
static struct llc_station_state_trans llc_stat_dupaddr_state_trans_4 = {
.ev = llc_stat_ev_ack_tmr_exp_lt_retry_cnt_max_retry,
.next_state = LLC_STATION_STATE_DUP_ADDR_CHK,
.ev_actions = llc_stat_dupaddr_state_actions_4,
};
/* state transition for LLC_STATION_EV_ACK_TMR_EXP_EQ_RETRY_CNT_MAX_RETRY
* event
*/
static llc_station_action_t llc_stat_dupaddr_state_actions_5[] = {
[0] = llc_station_ac_report_status, /* STATION UP */
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_dupaddr_state_trans_5 = {
.ev = llc_stat_ev_ack_tmr_exp_eq_retry_cnt_max_retry,
.next_state = LLC_STATION_STATE_UP,
.ev_actions = llc_stat_dupaddr_state_actions_5,
};
/* state transition for LLC_STATION_EV_DISABLE_REQ event */
static llc_station_action_t llc_stat_dupaddr_state_actions_6[] = {
[0] = llc_station_ac_report_status, /* STATION DOWN */
[1] = NULL,
};
static struct llc_station_state_trans llc_stat_dupaddr_state_trans_6 = {
.ev = llc_stat_ev_disable_req,
.next_state = LLC_STATION_STATE_DOWN,
.ev_actions = llc_stat_dupaddr_state_actions_6,
};
/* array of pointers; one to each transition */
static struct llc_station_state_trans *llc_stat_dupaddr_state_trans[] = {
[0] = &llc_stat_dupaddr_state_trans_6, /* Request */
[1] = &llc_stat_dupaddr_state_trans_4, /* Timer */
[2] = &llc_stat_dupaddr_state_trans_5,
[3] = &llc_stat_dupaddr_state_trans_1, /* Receive frame */
[4] = &llc_stat_dupaddr_state_trans_2,
[5] = &llc_stat_dupaddr_state_trans_3,
[6] = &llc_stat_state_trans_end,
};
static struct llc_station_state
llc_station_state_table[LLC_NBR_STATION_STATES] = {
[LLC_STATION_STATE_DOWN - 1] = {
.curr_state = LLC_STATION_STATE_DOWN,
.transitions = llc_stat_dwn_state_trans,
},
[LLC_STATION_STATE_DUP_ADDR_CHK - 1] = {
.curr_state = LLC_STATION_STATE_DUP_ADDR_CHK,
.transitions = llc_stat_dupaddr_state_trans,
},
[LLC_STATION_STATE_UP - 1] = {
.curr_state = LLC_STATION_STATE_UP,
.transitions = llc_stat_up_state_trans,
},
};
/**
* 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;
struct llc_station_state *curr_state =
&llc_station_state_table[llc_main_station.state - 1];
for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
if (!next_trans[i]->ev(skb)) {
rc = next_trans[i];
break;
}
return rc;
}
/**
* llc_station_free_ev - frees an event
* @skb: Address of the event
*
* Frees an event.
*/
static void llc_station_free_ev(struct sk_buff *skb)
{
struct llc_station_state_ev *ev = llc_station_ev(skb);
if (ev->type == LLC_STATION_EV_TYPE_PDU)
kfree_skb(skb);
}
/**
* llc_station_next_state - processes event and goes to the next state
* @skb: Address of the event
*
* Processes an event, executes any transitions related to that event and
* updates the state of the station.
*/
static u16 llc_station_next_state(struct sk_buff *skb)
{
u16 rc = 1;
struct llc_station_state_trans *trans;
if (llc_main_station.state > LLC_NBR_STATION_STATES)
goto out;
trans = llc_find_station_trans(skb);
if (trans) {
/* got the state to which we next transition; perform the
* actions associated with this transition before actually
* transitioning to the next state
*/
rc = llc_exec_station_trans_actions(trans, skb);
if (!rc)
/* transition station to next state if all actions
* execute successfully; done; wait for next event
*/
llc_main_station.state = trans->next_state;
} else
/* event not recognized in current state; re-queue it for
* processing again at a later time; return failure
*/
rc = 0;
out:
llc_station_free_ev(skb);
return rc;
}
/**
* llc_station_service_events - service events in the queue
*
* Get an event from the station event queue (if any); attempt to service
* the event; if event serviced, get the next event (if any) on the event
* queue; if event not service, re-queue the event on the event queue and
* attempt to service the next event; when serviced all events in queue,
* finished; if don't transition to different state, just service all
* events once; if transition to new state, service all events again.
* Caller must hold llc_main_station.ev_q.lock.
*/
static void llc_station_service_events(void)
{
struct sk_buff *skb;
while ((skb = skb_dequeue(&llc_main_station.ev_q.list)) != NULL)
llc_station_next_state(skb);
}
/**
* llc_station_state_process: queue event and try to process queue.
* @skb: Address of the event
*
* Queues an event (on the station event queue) for handling by the
* station state machine and attempts to process any queued-up events.
*/
static void llc_station_state_process(struct sk_buff *skb)
{
spin_lock_bh(&llc_main_station.ev_q.lock);
skb_queue_tail(&llc_main_station.ev_q.list, skb);
llc_station_service_events();
spin_unlock_bh(&llc_main_station.ev_q.lock);
}
static void llc_station_ack_tmr_cb(unsigned long timeout_data)
{
struct sk_buff *skb = alloc_skb(0, GFP_ATOMIC);
if (skb) {
struct llc_station_state_ev *ev = llc_station_ev(skb);
ev->type = LLC_STATION_EV_TYPE_ACK_TMR;
llc_station_state_process(skb);
}
}
/*
* 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_ev *ev = llc_station_ev(skb);
ev->type = LLC_STATION_EV_TYPE_PDU;
ev->reason = 0;
llc_station_state_process(skb);
}
int __init llc_station_init(void)
{
u16 rc = -ENOBUFS;
struct sk_buff *skb;
struct llc_station_state_ev *ev;
skb_queue_head_init(&llc_main_station.mac_pdu_q);
skb_queue_head_init(&llc_main_station.ev_q.list);
spin_lock_init(&llc_main_station.ev_q.lock);
setup_timer(&llc_main_station.ack_timer, llc_station_ack_tmr_cb,
(unsigned long)&llc_main_station);
llc_main_station.ack_timer.expires = jiffies +
sysctl_llc_station_ack_timeout;
skb = alloc_skb(0, GFP_ATOMIC);
if (!skb)
goto out;
rc = 0;
llc_set_station_handler(llc_station_rcv);
ev = llc_station_ev(skb);
memset(ev, 0, sizeof(*ev));
llc_main_station.maximum_retry = 1;
llc_main_station.state = LLC_STATION_STATE_DOWN;
ev->type = LLC_STATION_EV_TYPE_SIMPLE;
ev->prim_type = LLC_STATION_EV_ENABLE_WITHOUT_DUP_ADDR_CHECK;
rc = llc_station_next_state(skb);
out:
return rc;
}
void __exit llc_station_exit(void)
{
llc_set_station_handler(NULL);
}