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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/net/ax25/ax25_std_timer.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 *

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 * Copyright (C) Alan Cox GW4PTS ([email protected])

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 * Copyright (C) Jonathan Naylor G4KLX ([email protected])

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 * Copyright (C) Joerg Reuter DL1BKE ([email protected])

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 * Copyright (C) Frederic Rible F1OAT ([email protected])

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 */

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#include <linux/errno.h>

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#include <linux/types.h>

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#include <linux/socket.h>

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#include <linux/in.h>

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#include <linux/kernel.h>

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#include <linux/timer.h>

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#include <linux/string.h>

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#include <linux/sockios.h>

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#include <linux/net.h>

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#include <net/ax25.h>

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#include <linux/inet.h>

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#include <linux/netdevice.h>

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#include <linux/skbuff.h>

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#include <net/sock.h>

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#include <net/tcp_states.h>

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#include <linux/uaccess.h>

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#include <linux/fcntl.h>

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#include <linux/mm.h>

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#include <linux/interrupt.h>

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void ax25_std_heartbeat_expiry(ax25_cb *ax25)

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{

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	struct sock *sk = ax25->sk;

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	if (sk)

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		bh_lock_sock(sk);

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	switch (ax25->state) {

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	case AX25_STATE_0:

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	case AX25_STATE_2:

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		/* Magic here: If we listen() and a new link dies before it

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		   is accepted() it isn't 'dead' so doesn't get removed. */

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		if (!sk || sock_flag(sk, SOCK_DESTROY) ||

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		    (sk->sk_state == TCP_LISTEN &&

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		     sock_flag(sk, SOCK_DEAD))) {

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			if (sk) {

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				sock_hold(sk);

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				ax25_destroy_socket(ax25);

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				bh_unlock_sock(sk);

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				/* Ungrab socket and destroy it */

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				sock_put(sk);

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			} else

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				ax25_destroy_socket(ax25);

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			return;

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		}

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		break;

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	case AX25_STATE_3:

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	case AX25_STATE_4:

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		/*

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		 * Check the state of the receive buffer.

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		 */

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		if (sk != NULL) {

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			if (atomic_read(&sk->sk_rmem_alloc) <

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			    (sk->sk_rcvbuf >> 1) &&

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			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {

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				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;

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				ax25->condition &= ~AX25_COND_ACK_PENDING;

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				ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);

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				break;

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			}

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		}

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	}

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	if (sk)

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		bh_unlock_sock(sk);

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	ax25_start_heartbeat(ax25);

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}

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void ax25_std_t2timer_expiry(ax25_cb *ax25)

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{

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	if (ax25->condition & AX25_COND_ACK_PENDING) {

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		ax25->condition &= ~AX25_COND_ACK_PENDING;

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		ax25_std_timeout_response(ax25);

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	}

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}

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void ax25_std_t3timer_expiry(ax25_cb *ax25)

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{

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	ax25->n2count = 0;

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	ax25_std_transmit_enquiry(ax25);

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	ax25->state   = AX25_STATE_4;

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}

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void ax25_std_idletimer_expiry(ax25_cb *ax25)

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{

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	ax25_clear_queues(ax25);

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	ax25->n2count = 0;

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	ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);

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	ax25->state   = AX25_STATE_2;

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	ax25_calculate_t1(ax25);

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	ax25_start_t1timer(ax25);

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	ax25_stop_t2timer(ax25);

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	ax25_stop_t3timer(ax25);

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	if (ax25->sk != NULL) {

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		bh_lock_sock(ax25->sk);

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		ax25->sk->sk_state     = TCP_CLOSE;

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		ax25->sk->sk_err       = 0;

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		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;

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		if (!sock_flag(ax25->sk, SOCK_DEAD)) {

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			ax25->sk->sk_state_change(ax25->sk);

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			sock_set_flag(ax25->sk, SOCK_DEAD);

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		}

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		bh_unlock_sock(ax25->sk);

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	}

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}

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void ax25_std_t1timer_expiry(ax25_cb *ax25)

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{

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	switch (ax25->state) {

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	case AX25_STATE_1:

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		if (ax25->n2count == ax25->n2) {

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			if (ax25->modulus == AX25_MODULUS) {

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				ax25_disconnect(ax25, ETIMEDOUT);

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				return;

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			} else {

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				ax25->modulus = AX25_MODULUS;

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				ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];

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				ax25->n2count = 0;

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				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);

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			}

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		} else {

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			ax25->n2count++;

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			if (ax25->modulus == AX25_MODULUS)

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				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);

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			else

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				ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);

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		}

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		break;

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	case AX25_STATE_2:

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		if (ax25->n2count == ax25->n2) {

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			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);

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			if (!sock_flag(ax25->sk, SOCK_DESTROY))

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				ax25_disconnect(ax25, ETIMEDOUT);

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			return;

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		} else {

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			ax25->n2count++;

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			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);

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		}

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		break;

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	case AX25_STATE_3:

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		ax25->n2count = 1;

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		ax25_std_transmit_enquiry(ax25);

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		ax25->state   = AX25_STATE_4;

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		break;

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	case AX25_STATE_4:

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		if (ax25->n2count == ax25->n2) {

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			ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);

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			ax25_disconnect(ax25, ETIMEDOUT);

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			return;

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		} else {

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			ax25->n2count++;

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			ax25_std_transmit_enquiry(ax25);

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		}

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		break;

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	}

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	ax25_calculate_t1(ax25);

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	ax25_start_t1timer(ax25);

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}

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