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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8 *
9 * Most of this code is based on the SDL diagrams published in the 7th ARRL
10 * Computer Networking Conference papers. The diagrams have mistakes in them,
11 * but are mostly correct. Before you modify the code could you read the SDL
12 * diagrams as the code is not obvious and probably very easy to break.
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/timer.h>
20#include <linux/string.h>
21#include <linux/sockios.h>
22#include <linux/net.h>
23#include <net/ax25.h>
24#include <linux/inet.h>
25#include <linux/netdevice.h>
26#include <linux/skbuff.h>
27#include <net/sock.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070028#include <net/tcp_states.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/fcntl.h>
30#include <linux/mm.h>
31#include <linux/interrupt.h>
32#include <net/rose.h>
33
34/*
35 * State machine for state 1, Awaiting Call Accepted State.
36 * The handling of the timer(s) is in file rose_timer.c.
37 * Handling of state 0 and connection release is in af_rose.c.
38 */
39static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
40{
41 struct rose_sock *rose = rose_sk(sk);
42
43 switch (frametype) {
44 case ROSE_CALL_ACCEPTED:
45 rose_stop_timer(sk);
46 rose_start_idletimer(sk);
47 rose->condition = 0x00;
48 rose->vs = 0;
49 rose->va = 0;
50 rose->vr = 0;
51 rose->vl = 0;
52 rose->state = ROSE_STATE_3;
53 sk->sk_state = TCP_ESTABLISHED;
54 if (!sock_flag(sk, SOCK_DEAD))
55 sk->sk_state_change(sk);
56 break;
57
58 case ROSE_CLEAR_REQUEST:
59 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
60 rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
61 rose->neighbour->use--;
62 break;
63
64 default:
65 break;
66 }
67
68 return 0;
69}
70
71/*
72 * State machine for state 2, Awaiting Clear Confirmation State.
73 * The handling of the timer(s) is in file rose_timer.c
74 * Handling of state 0 and connection release is in af_rose.c.
75 */
76static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
77{
78 struct rose_sock *rose = rose_sk(sk);
79
80 switch (frametype) {
81 case ROSE_CLEAR_REQUEST:
82 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
83 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
84 rose->neighbour->use--;
85 break;
86
87 case ROSE_CLEAR_CONFIRMATION:
88 rose_disconnect(sk, 0, -1, -1);
89 rose->neighbour->use--;
90 break;
91
92 default:
93 break;
94 }
95
96 return 0;
97}
98
99/*
100 * State machine for state 3, Connected State.
101 * The handling of the timer(s) is in file rose_timer.c
102 * Handling of state 0 and connection release is in af_rose.c.
103 */
104static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
105{
106 struct rose_sock *rose = rose_sk(sk);
107 int queued = 0;
108
109 switch (frametype) {
110 case ROSE_RESET_REQUEST:
111 rose_stop_timer(sk);
112 rose_start_idletimer(sk);
113 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
114 rose->condition = 0x00;
115 rose->vs = 0;
116 rose->vr = 0;
117 rose->va = 0;
118 rose->vl = 0;
119 rose_requeue_frames(sk);
120 break;
121
122 case ROSE_CLEAR_REQUEST:
123 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
124 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
125 rose->neighbour->use--;
126 break;
127
128 case ROSE_RR:
129 case ROSE_RNR:
130 if (!rose_validate_nr(sk, nr)) {
131 rose_write_internal(sk, ROSE_RESET_REQUEST);
132 rose->condition = 0x00;
133 rose->vs = 0;
134 rose->vr = 0;
135 rose->va = 0;
136 rose->vl = 0;
137 rose->state = ROSE_STATE_4;
138 rose_start_t2timer(sk);
139 rose_stop_idletimer(sk);
140 } else {
141 rose_frames_acked(sk, nr);
142 if (frametype == ROSE_RNR) {
143 rose->condition |= ROSE_COND_PEER_RX_BUSY;
144 } else {
145 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
146 }
147 }
148 break;
149
150 case ROSE_DATA: /* XXX */
151 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
152 if (!rose_validate_nr(sk, nr)) {
153 rose_write_internal(sk, ROSE_RESET_REQUEST);
154 rose->condition = 0x00;
155 rose->vs = 0;
156 rose->vr = 0;
157 rose->va = 0;
158 rose->vl = 0;
159 rose->state = ROSE_STATE_4;
160 rose_start_t2timer(sk);
161 rose_stop_idletimer(sk);
162 break;
163 }
164 rose_frames_acked(sk, nr);
165 if (ns == rose->vr) {
166 rose_start_idletimer(sk);
Willem de Bruijnf4979fc2016-07-12 18:18:56 -0400167 if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
168 __sock_queue_rcv_skb(sk, skb) == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 rose->vr = (rose->vr + 1) % ROSE_MODULUS;
170 queued = 1;
171 } else {
172 /* Should never happen ! */
173 rose_write_internal(sk, ROSE_RESET_REQUEST);
174 rose->condition = 0x00;
175 rose->vs = 0;
176 rose->vr = 0;
177 rose->va = 0;
178 rose->vl = 0;
179 rose->state = ROSE_STATE_4;
180 rose_start_t2timer(sk);
181 rose_stop_idletimer(sk);
182 break;
183 }
184 if (atomic_read(&sk->sk_rmem_alloc) >
Eric Dumazet95b7d922008-01-15 03:30:35 -0800185 (sk->sk_rcvbuf >> 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 rose->condition |= ROSE_COND_OWN_RX_BUSY;
187 }
188 /*
189 * If the window is full, ack the frame, else start the
190 * acknowledge hold back timer.
191 */
192 if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
193 rose->condition &= ~ROSE_COND_ACK_PENDING;
194 rose_stop_timer(sk);
195 rose_enquiry_response(sk);
196 } else {
197 rose->condition |= ROSE_COND_ACK_PENDING;
198 rose_start_hbtimer(sk);
199 }
200 break;
201
202 default:
203 printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
204 break;
205 }
206
207 return queued;
208}
209
210/*
211 * State machine for state 4, Awaiting Reset Confirmation State.
212 * The handling of the timer(s) is in file rose_timer.c
213 * Handling of state 0 and connection release is in af_rose.c.
214 */
215static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
216{
217 struct rose_sock *rose = rose_sk(sk);
218
219 switch (frametype) {
220 case ROSE_RESET_REQUEST:
221 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
222 case ROSE_RESET_CONFIRMATION:
223 rose_stop_timer(sk);
224 rose_start_idletimer(sk);
225 rose->condition = 0x00;
226 rose->va = 0;
227 rose->vr = 0;
228 rose->vs = 0;
229 rose->vl = 0;
230 rose->state = ROSE_STATE_3;
231 rose_requeue_frames(sk);
232 break;
233
234 case ROSE_CLEAR_REQUEST:
235 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
236 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
237 rose->neighbour->use--;
238 break;
239
240 default:
241 break;
242 }
243
244 return 0;
245}
246
247/*
248 * State machine for state 5, Awaiting Call Acceptance State.
249 * The handling of the timer(s) is in file rose_timer.c
250 * Handling of state 0 and connection release is in af_rose.c.
251 */
252static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
253{
254 if (frametype == ROSE_CLEAR_REQUEST) {
255 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
256 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
257 rose_sk(sk)->neighbour->use--;
258 }
259
260 return 0;
261}
262
263/* Higher level upcall for a LAPB frame */
264int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
265{
266 struct rose_sock *rose = rose_sk(sk);
267 int queued = 0, frametype, ns, nr, q, d, m;
268
269 if (rose->state == ROSE_STATE_0)
270 return 0;
271
272 frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
273
274 switch (rose->state) {
275 case ROSE_STATE_1:
276 queued = rose_state1_machine(sk, skb, frametype);
277 break;
278 case ROSE_STATE_2:
279 queued = rose_state2_machine(sk, skb, frametype);
280 break;
281 case ROSE_STATE_3:
282 queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
283 break;
284 case ROSE_STATE_4:
285 queued = rose_state4_machine(sk, skb, frametype);
286 break;
287 case ROSE_STATE_5:
288 queued = rose_state5_machine(sk, skb, frametype);
289 break;
290 }
291
292 rose_kick(sk);
293
294 return queued;
295}