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
33 static void lapb_t1timer_expiry(struct timer_list *);
34 static void lapb_t2timer_expiry(struct timer_list *);
35
lapb_start_t1timer(struct lapb_cb * lapb)36 void 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 add_timer(&lapb->t1timer);
44 }
45
lapb_start_t2timer(struct lapb_cb * lapb)46 void lapb_start_t2timer(struct lapb_cb *lapb)
47 {
48 del_timer(&lapb->t2timer);
49
50 lapb->t2timer.function = lapb_t2timer_expiry;
51 lapb->t2timer.expires = jiffies + lapb->t2;
52
53 add_timer(&lapb->t2timer);
54 }
55
lapb_stop_t1timer(struct lapb_cb * lapb)56 void lapb_stop_t1timer(struct lapb_cb *lapb)
57 {
58 del_timer(&lapb->t1timer);
59 }
60
lapb_stop_t2timer(struct lapb_cb * lapb)61 void lapb_stop_t2timer(struct lapb_cb *lapb)
62 {
63 del_timer(&lapb->t2timer);
64 }
65
lapb_t1timer_running(struct lapb_cb * lapb)66 int lapb_t1timer_running(struct lapb_cb *lapb)
67 {
68 return timer_pending(&lapb->t1timer);
69 }
70
lapb_t2timer_expiry(struct timer_list * t)71 static void lapb_t2timer_expiry(struct timer_list *t)
72 {
73 struct lapb_cb *lapb = from_timer(lapb, t, t2timer);
74
75 if (lapb->condition & LAPB_ACK_PENDING_CONDITION) {
76 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
77 lapb_timeout_response(lapb);
78 }
79 }
80
lapb_t1timer_expiry(struct timer_list * t)81 static void lapb_t1timer_expiry(struct timer_list *t)
82 {
83 struct lapb_cb *lapb = from_timer(lapb, t, t1timer);
84
85 switch (lapb->state) {
86
87 /*
88 * If we are a DCE, keep going DM .. DM .. DM
89 */
90 case LAPB_STATE_0:
91 if (lapb->mode & LAPB_DCE)
92 lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
93 break;
94
95 /*
96 * Awaiting connection state, send SABM(E), up to N2 times.
97 */
98 case LAPB_STATE_1:
99 if (lapb->n2count == lapb->n2) {
100 lapb_clear_queues(lapb);
101 lapb->state = LAPB_STATE_0;
102 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
103 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
104 return;
105 } else {
106 lapb->n2count++;
107 if (lapb->mode & LAPB_EXTENDED) {
108 lapb_dbg(1, "(%p) S1 TX SABME(1)\n",
109 lapb->dev);
110 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
111 } else {
112 lapb_dbg(1, "(%p) S1 TX SABM(1)\n",
113 lapb->dev);
114 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
115 }
116 }
117 break;
118
119 /*
120 * Awaiting disconnection state, send DISC, up to N2 times.
121 */
122 case LAPB_STATE_2:
123 if (lapb->n2count == lapb->n2) {
124 lapb_clear_queues(lapb);
125 lapb->state = LAPB_STATE_0;
126 lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT);
127 lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
128 return;
129 } else {
130 lapb->n2count++;
131 lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev);
132 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
133 }
134 break;
135
136 /*
137 * Data transfer state, restransmit I frames, up to N2 times.
138 */
139 case LAPB_STATE_3:
140 if (lapb->n2count == lapb->n2) {
141 lapb_clear_queues(lapb);
142 lapb->state = LAPB_STATE_0;
143 lapb_stop_t2timer(lapb);
144 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
145 lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
146 return;
147 } else {
148 lapb->n2count++;
149 lapb_requeue_frames(lapb);
150 lapb_kick(lapb);
151 }
152 break;
153
154 /*
155 * Frame reject state, restransmit FRMR frames, up to N2 times.
156 */
157 case LAPB_STATE_4:
158 if (lapb->n2count == lapb->n2) {
159 lapb_clear_queues(lapb);
160 lapb->state = LAPB_STATE_0;
161 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
162 lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
163 return;
164 } else {
165 lapb->n2count++;
166 lapb_transmit_frmr(lapb);
167 }
168 break;
169 }
170
171 lapb_start_t1timer(lapb);
172 }
173