Merge branch 'master' into next
[linux-2.6.git] / net / rose / rose_in.c
1 /*
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/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>
28 #include <net/tcp_states.h>
29 #include <asm/system.h>
30 #include <linux/fcntl.h>
31 #include <linux/mm.h>
32 #include <linux/interrupt.h>
33 #include <net/rose.h>
34
35 /*
36  * State machine for state 1, Awaiting Call Accepted State.
37  * The handling of the timer(s) is in file rose_timer.c.
38  * Handling of state 0 and connection release is in af_rose.c.
39  */
40 static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
41 {
42         struct rose_sock *rose = rose_sk(sk);
43
44         switch (frametype) {
45         case ROSE_CALL_ACCEPTED:
46                 rose_stop_timer(sk);
47                 rose_start_idletimer(sk);
48                 rose->condition = 0x00;
49                 rose->vs        = 0;
50                 rose->va        = 0;
51                 rose->vr        = 0;
52                 rose->vl        = 0;
53                 rose->state     = ROSE_STATE_3;
54                 sk->sk_state    = TCP_ESTABLISHED;
55                 if (!sock_flag(sk, SOCK_DEAD))
56                         sk->sk_state_change(sk);
57                 break;
58
59         case ROSE_CLEAR_REQUEST:
60                 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
61                 rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
62                 rose->neighbour->use--;
63                 break;
64
65         default:
66                 break;
67         }
68
69         return 0;
70 }
71
72 /*
73  * State machine for state 2, Awaiting Clear Confirmation State.
74  * The handling of the timer(s) is in file rose_timer.c
75  * Handling of state 0 and connection release is in af_rose.c.
76  */
77 static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
78 {
79         struct rose_sock *rose = rose_sk(sk);
80
81         switch (frametype) {
82         case ROSE_CLEAR_REQUEST:
83                 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
84                 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
85                 rose->neighbour->use--;
86                 break;
87
88         case ROSE_CLEAR_CONFIRMATION:
89                 rose_disconnect(sk, 0, -1, -1);
90                 rose->neighbour->use--;
91                 break;
92
93         default:
94                 break;
95         }
96
97         return 0;
98 }
99
100 /*
101  * State machine for state 3, Connected State.
102  * The handling of the timer(s) is in file rose_timer.c
103  * Handling of state 0 and connection release is in af_rose.c.
104  */
105 static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
106 {
107         struct rose_sock *rose = rose_sk(sk);
108         int queued = 0;
109
110         switch (frametype) {
111         case ROSE_RESET_REQUEST:
112                 rose_stop_timer(sk);
113                 rose_start_idletimer(sk);
114                 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
115                 rose->condition = 0x00;
116                 rose->vs        = 0;
117                 rose->vr        = 0;
118                 rose->va        = 0;
119                 rose->vl        = 0;
120                 rose_requeue_frames(sk);
121                 break;
122
123         case ROSE_CLEAR_REQUEST:
124                 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
125                 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
126                 rose->neighbour->use--;
127                 break;
128
129         case ROSE_RR:
130         case ROSE_RNR:
131                 if (!rose_validate_nr(sk, nr)) {
132                         rose_write_internal(sk, ROSE_RESET_REQUEST);
133                         rose->condition = 0x00;
134                         rose->vs        = 0;
135                         rose->vr        = 0;
136                         rose->va        = 0;
137                         rose->vl        = 0;
138                         rose->state     = ROSE_STATE_4;
139                         rose_start_t2timer(sk);
140                         rose_stop_idletimer(sk);
141                 } else {
142                         rose_frames_acked(sk, nr);
143                         if (frametype == ROSE_RNR) {
144                                 rose->condition |= ROSE_COND_PEER_RX_BUSY;
145                         } else {
146                                 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
147                         }
148                 }
149                 break;
150
151         case ROSE_DATA: /* XXX */
152                 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
153                 if (!rose_validate_nr(sk, nr)) {
154                         rose_write_internal(sk, ROSE_RESET_REQUEST);
155                         rose->condition = 0x00;
156                         rose->vs        = 0;
157                         rose->vr        = 0;
158                         rose->va        = 0;
159                         rose->vl        = 0;
160                         rose->state     = ROSE_STATE_4;
161                         rose_start_t2timer(sk);
162                         rose_stop_idletimer(sk);
163                         break;
164                 }
165                 rose_frames_acked(sk, nr);
166                 if (ns == rose->vr) {
167                         rose_start_idletimer(sk);
168                         if (sock_queue_rcv_skb(sk, skb) == 0) {
169                                 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) >
185                             (sk->sk_rcvbuf >> 1))
186                                 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  */
215 static 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  */
252 static 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 */
264 int 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 }