1/*
2 *	LAPB release 002
3 *
4 *	This code REQUIRES 2.1.15 or higher/ NET3.038
5 *
6 *	This module:
7 *		This module is free software; you can redistribute it and/or
8 *		modify it under the terms of the GNU General Public License
9 *		as published by the Free Software Foundation; either version
10 *		2 of the License, or (at your option) any later version.
11 *
12 *	History
13 *	LAPB 001	Jonathan Naylor	Started Coding
14 *	LAPB 002	Jonathan Naylor	New timer architecture.
15 */
16
17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/errno.h>
20#include <linux/types.h>
21#include <linux/socket.h>
22#include <linux/in.h>
23#include <linux/kernel.h>
24#include <linux/jiffies.h>
25#include <linux/timer.h>
26#include <linux/string.h>
27#include <linux/sockios.h>
28#include <linux/net.h>
29#include <linux/inet.h>
30#include <linux/skbuff.h>
31#include <net/sock.h>
32#include <asm/uaccess.h>
33#include <linux/fcntl.h>
34#include <linux/mm.h>
35#include <linux/interrupt.h>
36#include <net/lapb.h>
37
38static void lapb_t1timer_expiry(unsigned long);
39static void lapb_t2timer_expiry(unsigned long);
40
41void lapb_start_t1timer(struct lapb_cb *lapb)
42{
43	del_timer(&lapb->t1timer);
44
45	lapb->t1timer.data     = (unsigned long)lapb;
46	lapb->t1timer.function = &lapb_t1timer_expiry;
47	lapb->t1timer.expires  = jiffies + lapb->t1;
48
49	add_timer(&lapb->t1timer);
50}
51
52void lapb_start_t2timer(struct lapb_cb *lapb)
53{
54	del_timer(&lapb->t2timer);
55
56	lapb->t2timer.data     = (unsigned long)lapb;
57	lapb->t2timer.function = &lapb_t2timer_expiry;
58	lapb->t2timer.expires  = jiffies + lapb->t2;
59
60	add_timer(&lapb->t2timer);
61}
62
63void lapb_stop_t1timer(struct lapb_cb *lapb)
64{
65	del_timer(&lapb->t1timer);
66}
67
68void lapb_stop_t2timer(struct lapb_cb *lapb)
69{
70	del_timer(&lapb->t2timer);
71}
72
73int lapb_t1timer_running(struct lapb_cb *lapb)
74{
75	return timer_pending(&lapb->t1timer);
76}
77
78static void lapb_t2timer_expiry(unsigned long param)
79{
80	struct lapb_cb *lapb = (struct lapb_cb *)param;
81
82	if (lapb->condition & LAPB_ACK_PENDING_CONDITION) {
83		lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
84		lapb_timeout_response(lapb);
85	}
86}
87
88static void lapb_t1timer_expiry(unsigned long param)
89{
90	struct lapb_cb *lapb = (struct lapb_cb *)param;
91
92	switch (lapb->state) {
93
94		/*
95		 *	If we are a DCE, keep going DM .. DM .. DM
96		 */
97		case LAPB_STATE_0:
98			if (lapb->mode & LAPB_DCE)
99				lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
100			break;
101
102		/*
103		 *	Awaiting connection state, send SABM(E), up to N2 times.
104		 */
105		case LAPB_STATE_1:
106			if (lapb->n2count == lapb->n2) {
107				lapb_clear_queues(lapb);
108				lapb->state = LAPB_STATE_0;
109				lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
110				lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
111				return;
112			} else {
113				lapb->n2count++;
114				if (lapb->mode & LAPB_EXTENDED) {
115					lapb_dbg(1, "(%p) S1 TX SABME(1)\n",
116						 lapb->dev);
117					lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
118				} else {
119					lapb_dbg(1, "(%p) S1 TX SABM(1)\n",
120						 lapb->dev);
121					lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
122				}
123			}
124			break;
125
126		/*
127		 *	Awaiting disconnection state, send DISC, up to N2 times.
128		 */
129		case LAPB_STATE_2:
130			if (lapb->n2count == lapb->n2) {
131				lapb_clear_queues(lapb);
132				lapb->state = LAPB_STATE_0;
133				lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT);
134				lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
135				return;
136			} else {
137				lapb->n2count++;
138				lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev);
139				lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
140			}
141			break;
142
143		/*
144		 *	Data transfer state, restransmit I frames, up to N2 times.
145		 */
146		case LAPB_STATE_3:
147			if (lapb->n2count == lapb->n2) {
148				lapb_clear_queues(lapb);
149				lapb->state = LAPB_STATE_0;
150				lapb_stop_t2timer(lapb);
151				lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
152				lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
153				return;
154			} else {
155				lapb->n2count++;
156				lapb_requeue_frames(lapb);
157				lapb_kick(lapb);
158			}
159			break;
160
161		/*
162		 *	Frame reject state, restransmit FRMR frames, up to N2 times.
163		 */
164		case LAPB_STATE_4:
165			if (lapb->n2count == lapb->n2) {
166				lapb_clear_queues(lapb);
167				lapb->state = LAPB_STATE_0;
168				lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
169				lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
170				return;
171			} else {
172				lapb->n2count++;
173				lapb_transmit_frmr(lapb);
174			}
175			break;
176	}
177
178	lapb_start_t1timer(lapb);
179}
180