/* * 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/config.h> #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); 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, llc_station_mac_sa, llc_station_mac_sa); 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); 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, llc_station_mac_sa, 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; struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev); 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, llc_station_mac_sa, 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); init_timer(&llc_main_station.ack_timer); llc_main_station.ack_timer.data = (unsigned long)&llc_main_station; llc_main_station.ack_timer.function = llc_station_ack_tmr_cb; 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); }