iucv: Fix bad merging.
[linux-2.6.git] / net / x25 / x25_in.c
1 /*
2  *      X.25 Packet Layer release 002
3  *
4  *      This is ALPHA test software. This code may break your machine,
5  *      randomly fail to work with new releases, misbehave and/or generally
6  *      screw up. It might even work.
7  *
8  *      This code REQUIRES 2.1.15 or higher
9  *
10  *      This module:
11  *              This module is free software; you can redistribute it and/or
12  *              modify it under the terms of the GNU General Public License
13  *              as published by the Free Software Foundation; either version
14  *              2 of the License, or (at your option) any later version.
15  *
16  *      History
17  *      X.25 001        Jonathan Naylor   Started coding.
18  *      X.25 002        Jonathan Naylor   Centralised disconnection code.
19  *                                        New timer architecture.
20  *      2000-03-20      Daniela Squassoni Disabling/enabling of facilities
21  *                                        negotiation.
22  *      2000-11-10      Henner Eisen      Check and reset for out-of-sequence
23  *                                        i-frames.
24  */
25
26 #include <linux/errno.h>
27 #include <linux/kernel.h>
28 #include <linux/string.h>
29 #include <linux/skbuff.h>
30 #include <net/sock.h>
31 #include <net/tcp_states.h>
32 #include <net/x25.h>
33
34 static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
35 {
36         struct sk_buff *skbo, *skbn = skb;
37         struct x25_sock *x25 = x25_sk(sk);
38
39         if (more) {
40                 x25->fraglen += skb->len;
41                 skb_queue_tail(&x25->fragment_queue, skb);
42                 skb_set_owner_r(skb, sk);
43                 return 0;
44         }
45
46         if (!more && x25->fraglen > 0) {        /* End of fragment */
47                 int len = x25->fraglen + skb->len;
48
49                 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
50                         kfree_skb(skb);
51                         return 1;
52                 }
53
54                 skb_queue_tail(&x25->fragment_queue, skb);
55
56                 skb_reset_transport_header(skbn);
57
58                 skbo = skb_dequeue(&x25->fragment_queue);
59                 skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
60                                           skbo->len);
61                 kfree_skb(skbo);
62
63                 while ((skbo =
64                         skb_dequeue(&x25->fragment_queue)) != NULL) {
65                         skb_pull(skbo, (x25->neighbour->extended) ?
66                                         X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
67                         skb_copy_from_linear_data(skbo,
68                                                   skb_put(skbn, skbo->len),
69                                                   skbo->len);
70                         kfree_skb(skbo);
71                 }
72
73                 x25->fraglen = 0;
74         }
75
76         skb_set_owner_r(skbn, sk);
77         skb_queue_tail(&sk->sk_receive_queue, skbn);
78         if (!sock_flag(sk, SOCK_DEAD))
79                 sk->sk_data_ready(sk, skbn->len);
80
81         return 0;
82 }
83
84 /*
85  * State machine for state 1, Awaiting Call Accepted State.
86  * The handling of the timer(s) is in file x25_timer.c.
87  * Handling of state 0 and connection release is in af_x25.c.
88  */
89 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
90 {
91         struct x25_address source_addr, dest_addr;
92
93         switch (frametype) {
94                 case X25_CALL_ACCEPTED: {
95                         struct x25_sock *x25 = x25_sk(sk);
96
97                         x25_stop_timer(sk);
98                         x25->condition = 0x00;
99                         x25->vs        = 0;
100                         x25->va        = 0;
101                         x25->vr        = 0;
102                         x25->vl        = 0;
103                         x25->state     = X25_STATE_3;
104                         sk->sk_state   = TCP_ESTABLISHED;
105                         /*
106                          *      Parse the data in the frame.
107                          */
108                         skb_pull(skb, X25_STD_MIN_LEN);
109                         skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
110                         skb_pull(skb,
111                                  x25_parse_facilities(skb, &x25->facilities,
112                                                 &x25->dte_facilities,
113                                                 &x25->vc_facil_mask));
114                         /*
115                          *      Copy any Call User Data.
116                          */
117                         if (skb->len >= 0) {
118                                 skb_copy_from_linear_data(skb,
119                                               x25->calluserdata.cuddata,
120                                               skb->len);
121                                 x25->calluserdata.cudlength = skb->len;
122                         }
123                         if (!sock_flag(sk, SOCK_DEAD))
124                                 sk->sk_state_change(sk);
125                         break;
126                 }
127                 case X25_CLEAR_REQUEST:
128                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
129                         x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
130                         break;
131
132                 default:
133                         break;
134         }
135
136         return 0;
137 }
138
139 /*
140  * State machine for state 2, Awaiting Clear Confirmation State.
141  * The handling of the timer(s) is in file x25_timer.c
142  * Handling of state 0 and connection release is in af_x25.c.
143  */
144 static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
145 {
146         switch (frametype) {
147
148                 case X25_CLEAR_REQUEST:
149                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
150                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
151                         break;
152
153                 case X25_CLEAR_CONFIRMATION:
154                         x25_disconnect(sk, 0, 0, 0);
155                         break;
156
157                 default:
158                         break;
159         }
160
161         return 0;
162 }
163
164 /*
165  * State machine for state 3, Connected State.
166  * The handling of the timer(s) is in file x25_timer.c
167  * Handling of state 0 and connection release is in af_x25.c.
168  */
169 static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
170 {
171         int queued = 0;
172         int modulus;
173         struct x25_sock *x25 = x25_sk(sk);
174
175         modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
176
177         switch (frametype) {
178
179                 case X25_RESET_REQUEST:
180                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
181                         x25_stop_timer(sk);
182                         x25->condition = 0x00;
183                         x25->vs        = 0;
184                         x25->vr        = 0;
185                         x25->va        = 0;
186                         x25->vl        = 0;
187                         x25_requeue_frames(sk);
188                         break;
189
190                 case X25_CLEAR_REQUEST:
191                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
192                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
193                         break;
194
195                 case X25_RR:
196                 case X25_RNR:
197                         if (!x25_validate_nr(sk, nr)) {
198                                 x25_clear_queues(sk);
199                                 x25_write_internal(sk, X25_RESET_REQUEST);
200                                 x25_start_t22timer(sk);
201                                 x25->condition = 0x00;
202                                 x25->vs        = 0;
203                                 x25->vr        = 0;
204                                 x25->va        = 0;
205                                 x25->vl        = 0;
206                                 x25->state     = X25_STATE_4;
207                         } else {
208                                 x25_frames_acked(sk, nr);
209                                 if (frametype == X25_RNR) {
210                                         x25->condition |= X25_COND_PEER_RX_BUSY;
211                                 } else {
212                                         x25->condition &= ~X25_COND_PEER_RX_BUSY;
213                                 }
214                         }
215                         break;
216
217                 case X25_DATA:  /* XXX */
218                         x25->condition &= ~X25_COND_PEER_RX_BUSY;
219                         if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
220                                 x25_clear_queues(sk);
221                                 x25_write_internal(sk, X25_RESET_REQUEST);
222                                 x25_start_t22timer(sk);
223                                 x25->condition = 0x00;
224                                 x25->vs        = 0;
225                                 x25->vr        = 0;
226                                 x25->va        = 0;
227                                 x25->vl        = 0;
228                                 x25->state     = X25_STATE_4;
229                                 break;
230                         }
231                         x25_frames_acked(sk, nr);
232                         if (ns == x25->vr) {
233                                 if (x25_queue_rx_frame(sk, skb, m) == 0) {
234                                         x25->vr = (x25->vr + 1) % modulus;
235                                         queued = 1;
236                                 } else {
237                                         /* Should never happen */
238                                         x25_clear_queues(sk);
239                                         x25_write_internal(sk, X25_RESET_REQUEST);
240                                         x25_start_t22timer(sk);
241                                         x25->condition = 0x00;
242                                         x25->vs        = 0;
243                                         x25->vr        = 0;
244                                         x25->va        = 0;
245                                         x25->vl        = 0;
246                                         x25->state     = X25_STATE_4;
247                                         break;
248                                 }
249                                 if (atomic_read(&sk->sk_rmem_alloc) >
250                                     (sk->sk_rcvbuf >> 1))
251                                         x25->condition |= X25_COND_OWN_RX_BUSY;
252                         }
253                         /*
254                          *      If the window is full Ack it immediately, else
255                          *      start the holdback timer.
256                          */
257                         if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
258                                 x25->condition &= ~X25_COND_ACK_PENDING;
259                                 x25_stop_timer(sk);
260                                 x25_enquiry_response(sk);
261                         } else {
262                                 x25->condition |= X25_COND_ACK_PENDING;
263                                 x25_start_t2timer(sk);
264                         }
265                         break;
266
267                 case X25_INTERRUPT_CONFIRMATION:
268                         x25->intflag = 0;
269                         break;
270
271                 case X25_INTERRUPT:
272                         if (sock_flag(sk, SOCK_URGINLINE))
273                                 queued = !sock_queue_rcv_skb(sk, skb);
274                         else {
275                                 skb_set_owner_r(skb, sk);
276                                 skb_queue_tail(&x25->interrupt_in_queue, skb);
277                                 queued = 1;
278                         }
279                         sk_send_sigurg(sk);
280                         x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
281                         break;
282
283                 default:
284                         printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
285                         break;
286         }
287
288         return queued;
289 }
290
291 /*
292  * State machine for state 4, Awaiting Reset Confirmation State.
293  * The handling of the timer(s) is in file x25_timer.c
294  * Handling of state 0 and connection release is in af_x25.c.
295  */
296 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
297 {
298         switch (frametype) {
299
300                 case X25_RESET_REQUEST:
301                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
302                 case X25_RESET_CONFIRMATION: {
303                         struct x25_sock *x25 = x25_sk(sk);
304
305                         x25_stop_timer(sk);
306                         x25->condition = 0x00;
307                         x25->va        = 0;
308                         x25->vr        = 0;
309                         x25->vs        = 0;
310                         x25->vl        = 0;
311                         x25->state     = X25_STATE_3;
312                         x25_requeue_frames(sk);
313                         break;
314                 }
315                 case X25_CLEAR_REQUEST:
316                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
317                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
318                         break;
319
320                 default:
321                         break;
322         }
323
324         return 0;
325 }
326
327 /* Higher level upcall for a LAPB frame */
328 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
329 {
330         struct x25_sock *x25 = x25_sk(sk);
331         int queued = 0, frametype, ns, nr, q, d, m;
332
333         if (x25->state == X25_STATE_0)
334                 return 0;
335
336         frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
337
338         switch (x25->state) {
339                 case X25_STATE_1:
340                         queued = x25_state1_machine(sk, skb, frametype);
341                         break;
342                 case X25_STATE_2:
343                         queued = x25_state2_machine(sk, skb, frametype);
344                         break;
345                 case X25_STATE_3:
346                         queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
347                         break;
348                 case X25_STATE_4:
349                         queued = x25_state4_machine(sk, skb, frametype);
350                         break;
351         }
352
353         x25_kick(sk);
354
355         return queued;
356 }
357
358 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
359 {
360         int queued = x25_process_rx_frame(sk, skb);
361
362         if (!queued)
363                 kfree_skb(skb);
364
365         return 0;
366 }