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/net/ax25/ax25_std_timer.c

http://github.com/mirrors/linux
C | 175 lines | 144 code | 17 blank | 14 comment | 30 complexity | 2347445efbea7906bfb54d7ec61b5dfe MD5 | raw file
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *
  4 * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
  5 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
  6 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
  7 * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
  8 */
  9#include <linux/errno.h>
 10#include <linux/types.h>
 11#include <linux/socket.h>
 12#include <linux/in.h>
 13#include <linux/kernel.h>
 14#include <linux/timer.h>
 15#include <linux/string.h>
 16#include <linux/sockios.h>
 17#include <linux/net.h>
 18#include <net/ax25.h>
 19#include <linux/inet.h>
 20#include <linux/netdevice.h>
 21#include <linux/skbuff.h>
 22#include <net/sock.h>
 23#include <net/tcp_states.h>
 24#include <linux/uaccess.h>
 25#include <linux/fcntl.h>
 26#include <linux/mm.h>
 27#include <linux/interrupt.h>
 28
 29void ax25_std_heartbeat_expiry(ax25_cb *ax25)
 30{
 31	struct sock *sk = ax25->sk;
 32
 33	if (sk)
 34		bh_lock_sock(sk);
 35
 36	switch (ax25->state) {
 37	case AX25_STATE_0:
 38	case AX25_STATE_2:
 39		/* Magic here: If we listen() and a new link dies before it
 40		   is accepted() it isn't 'dead' so doesn't get removed. */
 41		if (!sk || sock_flag(sk, SOCK_DESTROY) ||
 42		    (sk->sk_state == TCP_LISTEN &&
 43		     sock_flag(sk, SOCK_DEAD))) {
 44			if (sk) {
 45				sock_hold(sk);
 46				ax25_destroy_socket(ax25);
 47				bh_unlock_sock(sk);
 48				/* Ungrab socket and destroy it */
 49				sock_put(sk);
 50			} else
 51				ax25_destroy_socket(ax25);
 52			return;
 53		}
 54		break;
 55
 56	case AX25_STATE_3:
 57	case AX25_STATE_4:
 58		/*
 59		 * Check the state of the receive buffer.
 60		 */
 61		if (sk != NULL) {
 62			if (atomic_read(&sk->sk_rmem_alloc) <
 63			    (sk->sk_rcvbuf >> 1) &&
 64			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
 65				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
 66				ax25->condition &= ~AX25_COND_ACK_PENDING;
 67				ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
 68				break;
 69			}
 70		}
 71	}
 72
 73	if (sk)
 74		bh_unlock_sock(sk);
 75
 76	ax25_start_heartbeat(ax25);
 77}
 78
 79void ax25_std_t2timer_expiry(ax25_cb *ax25)
 80{
 81	if (ax25->condition & AX25_COND_ACK_PENDING) {
 82		ax25->condition &= ~AX25_COND_ACK_PENDING;
 83		ax25_std_timeout_response(ax25);
 84	}
 85}
 86
 87void ax25_std_t3timer_expiry(ax25_cb *ax25)
 88{
 89	ax25->n2count = 0;
 90	ax25_std_transmit_enquiry(ax25);
 91	ax25->state   = AX25_STATE_4;
 92}
 93
 94void ax25_std_idletimer_expiry(ax25_cb *ax25)
 95{
 96	ax25_clear_queues(ax25);
 97
 98	ax25->n2count = 0;
 99	ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
100	ax25->state   = AX25_STATE_2;
101
102	ax25_calculate_t1(ax25);
103	ax25_start_t1timer(ax25);
104	ax25_stop_t2timer(ax25);
105	ax25_stop_t3timer(ax25);
106
107	if (ax25->sk != NULL) {
108		bh_lock_sock(ax25->sk);
109		ax25->sk->sk_state     = TCP_CLOSE;
110		ax25->sk->sk_err       = 0;
111		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
112		if (!sock_flag(ax25->sk, SOCK_DEAD)) {
113			ax25->sk->sk_state_change(ax25->sk);
114			sock_set_flag(ax25->sk, SOCK_DEAD);
115		}
116		bh_unlock_sock(ax25->sk);
117	}
118}
119
120void ax25_std_t1timer_expiry(ax25_cb *ax25)
121{
122	switch (ax25->state) {
123	case AX25_STATE_1:
124		if (ax25->n2count == ax25->n2) {
125			if (ax25->modulus == AX25_MODULUS) {
126				ax25_disconnect(ax25, ETIMEDOUT);
127				return;
128			} else {
129				ax25->modulus = AX25_MODULUS;
130				ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
131				ax25->n2count = 0;
132				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
133			}
134		} else {
135			ax25->n2count++;
136			if (ax25->modulus == AX25_MODULUS)
137				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
138			else
139				ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
140		}
141		break;
142
143	case AX25_STATE_2:
144		if (ax25->n2count == ax25->n2) {
145			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
146			if (!sock_flag(ax25->sk, SOCK_DESTROY))
147				ax25_disconnect(ax25, ETIMEDOUT);
148			return;
149		} else {
150			ax25->n2count++;
151			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
152		}
153		break;
154
155	case AX25_STATE_3:
156		ax25->n2count = 1;
157		ax25_std_transmit_enquiry(ax25);
158		ax25->state   = AX25_STATE_4;
159		break;
160
161	case AX25_STATE_4:
162		if (ax25->n2count == ax25->n2) {
163			ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
164			ax25_disconnect(ax25, ETIMEDOUT);
165			return;
166		} else {
167			ax25->n2count++;
168			ax25_std_transmit_enquiry(ax25);
169		}
170		break;
171	}
172
173	ax25_calculate_t1(ax25);
174	ax25_start_t1timer(ax25);
175}