Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * LAPB release 002
4 *
5 * This code REQUIRES 2.1.15 or higher/ NET3.038
6 *
7 * History
8 * LAPB 001 Jonathan Naylor Started Coding
9 * LAPB 002 Jonathan Naylor New timer architecture.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/errno.h>
15#include <linux/types.h>
16#include <linux/socket.h>
17#include <linux/in.h>
18#include <linux/kernel.h>
19#include <linux/jiffies.h>
20#include <linux/timer.h>
21#include <linux/string.h>
22#include <linux/sockios.h>
23#include <linux/net.h>
24#include <linux/inet.h>
25#include <linux/skbuff.h>
26#include <net/sock.h>
27#include <linux/uaccess.h>
28#include <linux/fcntl.h>
29#include <linux/mm.h>
30#include <linux/interrupt.h>
31#include <net/lapb.h>
32
33static void lapb_t1timer_expiry(struct timer_list *);
34static void lapb_t2timer_expiry(struct timer_list *);
35
36void lapb_start_t1timer(struct lapb_cb *lapb)
37{
38 del_timer(&lapb->t1timer);
39
40 lapb->t1timer.function = lapb_t1timer_expiry;
41 lapb->t1timer.expires = jiffies + lapb->t1;
42
43 lapb->t1timer_stop = false;
44 add_timer(&lapb->t1timer);
45}
46
47void lapb_start_t2timer(struct lapb_cb *lapb)
48{
49 del_timer(&lapb->t2timer);
50
51 lapb->t2timer.function = lapb_t2timer_expiry;
52 lapb->t2timer.expires = jiffies + lapb->t2;
53
54 lapb->t2timer_stop = false;
55 add_timer(&lapb->t2timer);
56}
57
58void lapb_stop_t1timer(struct lapb_cb *lapb)
59{
60 lapb->t1timer_stop = true;
61 del_timer(&lapb->t1timer);
62}
63
64void lapb_stop_t2timer(struct lapb_cb *lapb)
65{
66 lapb->t2timer_stop = true;
67 del_timer(&lapb->t2timer);
68}
69
70int lapb_t1timer_running(struct lapb_cb *lapb)
71{
72 return timer_pending(&lapb->t1timer);
73}
74
75static void lapb_t2timer_expiry(struct timer_list *t)
76{
77 struct lapb_cb *lapb = from_timer(lapb, t, t2timer);
78
79 spin_lock_bh(&lapb->lock);
80 if (timer_pending(&lapb->t2timer)) /* A new timer has been set up */
81 goto out;
82 if (lapb->t2timer_stop) /* The timer has been stopped */
83 goto out;
84
85 if (lapb->condition & LAPB_ACK_PENDING_CONDITION) {
86 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
87 lapb_timeout_response(lapb);
88 }
89
90out:
91 spin_unlock_bh(&lapb->lock);
92}
93
94static void lapb_t1timer_expiry(struct timer_list *t)
95{
96 struct lapb_cb *lapb = from_timer(lapb, t, t1timer);
97
98 spin_lock_bh(&lapb->lock);
99 if (timer_pending(&lapb->t1timer)) /* A new timer has been set up */
100 goto out;
101 if (lapb->t1timer_stop) /* The timer has been stopped */
102 goto out;
103
104 switch (lapb->state) {
105
106 /*
107 * If we are a DCE, send DM up to N2 times, then switch to
108 * STATE_1 and send SABM(E).
109 */
110 case LAPB_STATE_0:
111 if (lapb->mode & LAPB_DCE &&
112 lapb->n2count != lapb->n2) {
113 lapb->n2count++;
114 lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
115 } else {
116 lapb->state = LAPB_STATE_1;
117 lapb_establish_data_link(lapb);
118 }
119 break;
120
121 /*
122 * Awaiting connection state, send SABM(E), up to N2 times.
123 */
124 case LAPB_STATE_1:
125 if (lapb->n2count == lapb->n2) {
126 lapb_clear_queues(lapb);
127 lapb->state = LAPB_STATE_0;
128 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
129 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
130 goto out;
131 } else {
132 lapb->n2count++;
133 if (lapb->mode & LAPB_EXTENDED) {
134 lapb_dbg(1, "(%p) S1 TX SABME(1)\n",
135 lapb->dev);
136 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
137 } else {
138 lapb_dbg(1, "(%p) S1 TX SABM(1)\n",
139 lapb->dev);
140 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
141 }
142 }
143 break;
144
145 /*
146 * Awaiting disconnection state, send DISC, up to N2 times.
147 */
148 case LAPB_STATE_2:
149 if (lapb->n2count == lapb->n2) {
150 lapb_clear_queues(lapb);
151 lapb->state = LAPB_STATE_0;
152 lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT);
153 lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
154 goto out;
155 } else {
156 lapb->n2count++;
157 lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev);
158 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
159 }
160 break;
161
162 /*
163 * Data transfer state, restransmit I frames, up to N2 times.
164 */
165 case LAPB_STATE_3:
166 if (lapb->n2count == lapb->n2) {
167 lapb_clear_queues(lapb);
168 lapb->state = LAPB_STATE_0;
169 lapb_stop_t2timer(lapb);
170 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
171 lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
172 goto out;
173 } else {
174 lapb->n2count++;
175 lapb_requeue_frames(lapb);
176 lapb_kick(lapb);
177 }
178 break;
179
180 /*
181 * Frame reject state, restransmit FRMR frames, up to N2 times.
182 */
183 case LAPB_STATE_4:
184 if (lapb->n2count == lapb->n2) {
185 lapb_clear_queues(lapb);
186 lapb->state = LAPB_STATE_0;
187 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
188 lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
189 goto out;
190 } else {
191 lapb->n2count++;
192 lapb_transmit_frmr(lapb);
193 }
194 break;
195 }
196
197 lapb_start_t1timer(lapb);
198
199out:
200 spin_unlock_bh(&lapb->lock);
201}