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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>
19#include <linux/sched.h>
20#include <linux/timer.h>
21#include <linux/string.h>
22#include <linux/sockios.h>
23#include <linux/net.h>
24#include <net/ax25.h>
25#include <linux/inet.h>
26#include <linux/netdevice.h>
27#include <linux/skbuff.h>
28#include <net/sock.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070029#include <net/tcp_states.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <asm/system.h>
31#include <linux/fcntl.h>
32#include <linux/mm.h>
33#include <linux/interrupt.h>
34#include <net/rose.h>
35
36/*
37 * State machine for state 1, Awaiting Call Accepted State.
38 * The handling of the timer(s) is in file rose_timer.c.
39 * Handling of state 0 and connection release is in af_rose.c.
40 */
41static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
42{
43 struct rose_sock *rose = rose_sk(sk);
44
45 switch (frametype) {
46 case ROSE_CALL_ACCEPTED:
47 rose_stop_timer(sk);
48 rose_start_idletimer(sk);
49 rose->condition = 0x00;
50 rose->vs = 0;
51 rose->va = 0;
52 rose->vr = 0;
53 rose->vl = 0;
54 rose->state = ROSE_STATE_3;
55 sk->sk_state = TCP_ESTABLISHED;
56 if (!sock_flag(sk, SOCK_DEAD))
57 sk->sk_state_change(sk);
58 break;
59
60 case ROSE_CLEAR_REQUEST:
61 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
62 rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
63 rose->neighbour->use--;
64 break;
65
66 default:
67 break;
68 }
69
70 return 0;
71}
72
73/*
74 * State machine for state 2, Awaiting Clear Confirmation State.
75 * The handling of the timer(s) is in file rose_timer.c
76 * Handling of state 0 and connection release is in af_rose.c.
77 */
78static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
79{
80 struct rose_sock *rose = rose_sk(sk);
81
82 switch (frametype) {
83 case ROSE_CLEAR_REQUEST:
84 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
85 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
86 rose->neighbour->use--;
87 break;
88
89 case ROSE_CLEAR_CONFIRMATION:
90 rose_disconnect(sk, 0, -1, -1);
91 rose->neighbour->use--;
92 break;
93
94 default:
95 break;
96 }
97
98 return 0;
99}
100
101/*
102 * State machine for state 3, Connected State.
103 * The handling of the timer(s) is in file rose_timer.c
104 * Handling of state 0 and connection release is in af_rose.c.
105 */
106static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
107{
108 struct rose_sock *rose = rose_sk(sk);
109 int queued = 0;
110
111 switch (frametype) {
112 case ROSE_RESET_REQUEST:
113 rose_stop_timer(sk);
114 rose_start_idletimer(sk);
115 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
116 rose->condition = 0x00;
117 rose->vs = 0;
118 rose->vr = 0;
119 rose->va = 0;
120 rose->vl = 0;
121 rose_requeue_frames(sk);
122 break;
123
124 case ROSE_CLEAR_REQUEST:
125 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
126 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
127 rose->neighbour->use--;
128 break;
129
130 case ROSE_RR:
131 case ROSE_RNR:
132 if (!rose_validate_nr(sk, nr)) {
133 rose_write_internal(sk, ROSE_RESET_REQUEST);
134 rose->condition = 0x00;
135 rose->vs = 0;
136 rose->vr = 0;
137 rose->va = 0;
138 rose->vl = 0;
139 rose->state = ROSE_STATE_4;
140 rose_start_t2timer(sk);
141 rose_stop_idletimer(sk);
142 } else {
143 rose_frames_acked(sk, nr);
144 if (frametype == ROSE_RNR) {
145 rose->condition |= ROSE_COND_PEER_RX_BUSY;
146 } else {
147 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
148 }
149 }
150 break;
151
152 case ROSE_DATA: /* XXX */
153 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
154 if (!rose_validate_nr(sk, nr)) {
155 rose_write_internal(sk, ROSE_RESET_REQUEST);
156 rose->condition = 0x00;
157 rose->vs = 0;
158 rose->vr = 0;
159 rose->va = 0;
160 rose->vl = 0;
161 rose->state = ROSE_STATE_4;
162 rose_start_t2timer(sk);
163 rose_stop_idletimer(sk);
164 break;
165 }
166 rose_frames_acked(sk, nr);
167 if (ns == rose->vr) {
168 rose_start_idletimer(sk);
169 if (sock_queue_rcv_skb(sk, skb) == 0) {
170 rose->vr = (rose->vr + 1) % ROSE_MODULUS;
171 queued = 1;
172 } else {
173 /* Should never happen ! */
174 rose_write_internal(sk, ROSE_RESET_REQUEST);
175 rose->condition = 0x00;
176 rose->vs = 0;
177 rose->vr = 0;
178 rose->va = 0;
179 rose->vl = 0;
180 rose->state = ROSE_STATE_4;
181 rose_start_t2timer(sk);
182 rose_stop_idletimer(sk);
183 break;
184 }
185 if (atomic_read(&sk->sk_rmem_alloc) >
186 (sk->sk_rcvbuf / 2))
187 rose->condition |= ROSE_COND_OWN_RX_BUSY;
188 }
189 /*
190 * If the window is full, ack the frame, else start the
191 * acknowledge hold back timer.
192 */
193 if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
194 rose->condition &= ~ROSE_COND_ACK_PENDING;
195 rose_stop_timer(sk);
196 rose_enquiry_response(sk);
197 } else {
198 rose->condition |= ROSE_COND_ACK_PENDING;
199 rose_start_hbtimer(sk);
200 }
201 break;
202
203 default:
204 printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
205 break;
206 }
207
208 return queued;
209}
210
211/*
212 * State machine for state 4, Awaiting Reset Confirmation State.
213 * The handling of the timer(s) is in file rose_timer.c
214 * Handling of state 0 and connection release is in af_rose.c.
215 */
216static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
217{
218 struct rose_sock *rose = rose_sk(sk);
219
220 switch (frametype) {
221 case ROSE_RESET_REQUEST:
222 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
223 case ROSE_RESET_CONFIRMATION:
224 rose_stop_timer(sk);
225 rose_start_idletimer(sk);
226 rose->condition = 0x00;
227 rose->va = 0;
228 rose->vr = 0;
229 rose->vs = 0;
230 rose->vl = 0;
231 rose->state = ROSE_STATE_3;
232 rose_requeue_frames(sk);
233 break;
234
235 case ROSE_CLEAR_REQUEST:
236 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
237 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
238 rose->neighbour->use--;
239 break;
240
241 default:
242 break;
243 }
244
245 return 0;
246}
247
248/*
249 * State machine for state 5, Awaiting Call Acceptance State.
250 * The handling of the timer(s) is in file rose_timer.c
251 * Handling of state 0 and connection release is in af_rose.c.
252 */
253static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
254{
255 if (frametype == ROSE_CLEAR_REQUEST) {
256 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
257 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
258 rose_sk(sk)->neighbour->use--;
259 }
260
261 return 0;
262}
263
264/* Higher level upcall for a LAPB frame */
265int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
266{
267 struct rose_sock *rose = rose_sk(sk);
268 int queued = 0, frametype, ns, nr, q, d, m;
269
270 if (rose->state == ROSE_STATE_0)
271 return 0;
272
273 frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
274
275 switch (rose->state) {
276 case ROSE_STATE_1:
277 queued = rose_state1_machine(sk, skb, frametype);
278 break;
279 case ROSE_STATE_2:
280 queued = rose_state2_machine(sk, skb, frametype);
281 break;
282 case ROSE_STATE_3:
283 queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
284 break;
285 case ROSE_STATE_4:
286 queued = rose_state4_machine(sk, skb, frametype);
287 break;
288 case ROSE_STATE_5:
289 queued = rose_state5_machine(sk, skb, frametype);
290 break;
291 }
292
293 rose_kick(sk);
294
295 return queued;
296}