File: /usr/src/linux/net/rose/rose_in.c
1 /*
2 * ROSE release 003
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 * Most of this code is based on the SDL diagrams published in the 7th
13 * ARRL Computer Networking Conference papers. The diagrams have mistakes
14 * in them, but are mostly correct. Before you modify the code could you
15 * read the SDL diagrams as the code is not obvious and probably very
16 * easy to break;
17 *
18 * History
19 * ROSE 001 Jonathan(G4KLX) Cloned from nr_in.c
20 * ROSE 002 Jonathan(G4KLX) Return cause and diagnostic codes from Clear Requests.
21 * ROSE 003 Jonathan(G4KLX) New timer architecture.
22 * Removed M bit processing.
23 */
24
25 #include <linux/errno.h>
26 #include <linux/types.h>
27 #include <linux/socket.h>
28 #include <linux/in.h>
29 #include <linux/kernel.h>
30 #include <linux/sched.h>
31 #include <linux/timer.h>
32 #include <linux/string.h>
33 #include <linux/sockios.h>
34 #include <linux/net.h>
35 #include <net/ax25.h>
36 #include <linux/inet.h>
37 #include <linux/netdevice.h>
38 #include <linux/skbuff.h>
39 #include <net/sock.h>
40 #include <net/ip.h> /* For ip_rcv */
41 #include <asm/segment.h>
42 #include <asm/system.h>
43 #include <linux/fcntl.h>
44 #include <linux/mm.h>
45 #include <linux/interrupt.h>
46 #include <net/rose.h>
47
48 /*
49 * State machine for state 1, Awaiting Call Accepted State.
50 * The handling of the timer(s) is in file rose_timer.c.
51 * Handling of state 0 and connection release is in af_rose.c.
52 */
53 static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
54 {
55 switch (frametype) {
56
57 case ROSE_CALL_ACCEPTED:
58 rose_stop_timer(sk);
59 rose_start_idletimer(sk);
60 sk->protinfo.rose->condition = 0x00;
61 sk->protinfo.rose->vs = 0;
62 sk->protinfo.rose->va = 0;
63 sk->protinfo.rose->vr = 0;
64 sk->protinfo.rose->vl = 0;
65 sk->protinfo.rose->state = ROSE_STATE_3;
66 sk->state = TCP_ESTABLISHED;
67 if (!sk->dead)
68 sk->state_change(sk);
69 break;
70
71 case ROSE_CLEAR_REQUEST:
72 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
73 rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
74 sk->protinfo.rose->neighbour->use--;
75 break;
76
77 default:
78 break;
79 }
80
81 return 0;
82 }
83
84 /*
85 * State machine for state 2, Awaiting Clear Confirmation State.
86 * The handling of the timer(s) is in file rose_timer.c
87 * Handling of state 0 and connection release is in af_rose.c.
88 */
89 static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
90 {
91 switch (frametype) {
92
93 case ROSE_CLEAR_REQUEST:
94 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
95 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
96 sk->protinfo.rose->neighbour->use--;
97 break;
98
99 case ROSE_CLEAR_CONFIRMATION:
100 rose_disconnect(sk, 0, -1, -1);
101 sk->protinfo.rose->neighbour->use--;
102 break;
103
104 default:
105 break;
106 }
107
108 return 0;
109 }
110
111 /*
112 * State machine for state 3, Connected State.
113 * The handling of the timer(s) is in file rose_timer.c
114 * Handling of state 0 and connection release is in af_rose.c.
115 */
116 static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
117 {
118 int queued = 0;
119
120 switch (frametype) {
121
122 case ROSE_RESET_REQUEST:
123 rose_stop_timer(sk);
124 rose_start_idletimer(sk);
125 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
126 sk->protinfo.rose->condition = 0x00;
127 sk->protinfo.rose->vs = 0;
128 sk->protinfo.rose->vr = 0;
129 sk->protinfo.rose->va = 0;
130 sk->protinfo.rose->vl = 0;
131 rose_requeue_frames(sk);
132 break;
133
134 case ROSE_CLEAR_REQUEST:
135 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
136 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
137 sk->protinfo.rose->neighbour->use--;
138 break;
139
140 case ROSE_RR:
141 case ROSE_RNR:
142 if (!rose_validate_nr(sk, nr)) {
143 rose_write_internal(sk, ROSE_RESET_REQUEST);
144 sk->protinfo.rose->condition = 0x00;
145 sk->protinfo.rose->vs = 0;
146 sk->protinfo.rose->vr = 0;
147 sk->protinfo.rose->va = 0;
148 sk->protinfo.rose->vl = 0;
149 sk->protinfo.rose->state = ROSE_STATE_4;
150 rose_start_t2timer(sk);
151 rose_stop_idletimer(sk);
152 } else {
153 rose_frames_acked(sk, nr);
154 if (frametype == ROSE_RNR) {
155 sk->protinfo.rose->condition |= ROSE_COND_PEER_RX_BUSY;
156 } else {
157 sk->protinfo.rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
158 }
159 }
160 break;
161
162 case ROSE_DATA: /* XXX */
163 sk->protinfo.rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
164 if (!rose_validate_nr(sk, nr)) {
165 rose_write_internal(sk, ROSE_RESET_REQUEST);
166 sk->protinfo.rose->condition = 0x00;
167 sk->protinfo.rose->vs = 0;
168 sk->protinfo.rose->vr = 0;
169 sk->protinfo.rose->va = 0;
170 sk->protinfo.rose->vl = 0;
171 sk->protinfo.rose->state = ROSE_STATE_4;
172 rose_start_t2timer(sk);
173 rose_stop_idletimer(sk);
174 break;
175 }
176 rose_frames_acked(sk, nr);
177 if (ns == sk->protinfo.rose->vr) {
178 rose_start_idletimer(sk);
179 if (sock_queue_rcv_skb(sk, skb) == 0) {
180 sk->protinfo.rose->vr = (sk->protinfo.rose->vr + 1) % ROSE_MODULUS;
181 queued = 1;
182 } else {
183 /* Should never happen ! */
184 rose_write_internal(sk, ROSE_RESET_REQUEST);
185 sk->protinfo.rose->condition = 0x00;
186 sk->protinfo.rose->vs = 0;
187 sk->protinfo.rose->vr = 0;
188 sk->protinfo.rose->va = 0;
189 sk->protinfo.rose->vl = 0;
190 sk->protinfo.rose->state = ROSE_STATE_4;
191 rose_start_t2timer(sk);
192 rose_stop_idletimer(sk);
193 break;
194 }
195 if (atomic_read(&sk->rmem_alloc) > (sk->rcvbuf / 2))
196 sk->protinfo.rose->condition |= ROSE_COND_OWN_RX_BUSY;
197 }
198 /*
199 * If the window is full, ack the frame, else start the
200 * acknowledge hold back timer.
201 */
202 if (((sk->protinfo.rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == sk->protinfo.rose->vr) {
203 sk->protinfo.rose->condition &= ~ROSE_COND_ACK_PENDING;
204 rose_stop_timer(sk);
205 rose_enquiry_response(sk);
206 } else {
207 sk->protinfo.rose->condition |= ROSE_COND_ACK_PENDING;
208 rose_start_hbtimer(sk);
209 }
210 break;
211
212 default:
213 printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
214 break;
215 }
216
217 return queued;
218 }
219
220 /*
221 * State machine for state 4, Awaiting Reset Confirmation State.
222 * The handling of the timer(s) is in file rose_timer.c
223 * Handling of state 0 and connection release is in af_rose.c.
224 */
225 static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
226 {
227 switch (frametype) {
228
229 case ROSE_RESET_REQUEST:
230 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
231 case ROSE_RESET_CONFIRMATION:
232 rose_stop_timer(sk);
233 rose_start_idletimer(sk);
234 sk->protinfo.rose->condition = 0x00;
235 sk->protinfo.rose->va = 0;
236 sk->protinfo.rose->vr = 0;
237 sk->protinfo.rose->vs = 0;
238 sk->protinfo.rose->vl = 0;
239 sk->protinfo.rose->state = ROSE_STATE_3;
240 rose_requeue_frames(sk);
241 break;
242
243 case ROSE_CLEAR_REQUEST:
244 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
245 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
246 sk->protinfo.rose->neighbour->use--;
247 break;
248
249 default:
250 break;
251 }
252
253 return 0;
254 }
255
256 /*
257 * State machine for state 5, Awaiting Call Acceptance State.
258 * The handling of the timer(s) is in file rose_timer.c
259 * Handling of state 0 and connection release is in af_rose.c.
260 */
261 static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
262 {
263 if (frametype == ROSE_CLEAR_REQUEST) {
264 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
265 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
266 sk->protinfo.rose->neighbour->use--;
267 }
268
269 return 0;
270 }
271
272 /* Higher level upcall for a LAPB frame */
273 int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
274 {
275 int queued = 0, frametype, ns, nr, q, d, m;
276
277 if (sk->protinfo.rose->state == ROSE_STATE_0)
278 return 0;
279
280 frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
281
282 switch (sk->protinfo.rose->state) {
283 case ROSE_STATE_1:
284 queued = rose_state1_machine(sk, skb, frametype);
285 break;
286 case ROSE_STATE_2:
287 queued = rose_state2_machine(sk, skb, frametype);
288 break;
289 case ROSE_STATE_3:
290 queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
291 break;
292 case ROSE_STATE_4:
293 queued = rose_state4_machine(sk, skb, frametype);
294 break;
295 case ROSE_STATE_5:
296 queued = rose_state5_machine(sk, skb, frametype);
297 break;
298 }
299
300 rose_kick(sk);
301
302 return queued;
303 }
304