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[mirror_ubuntu-artful-kernel.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 skbn->h.raw = skbn->data;
57
58 skbo = skb_dequeue(&x25->fragment_queue);
59 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
60 kfree_skb(skbo);
61
62 while ((skbo =
63 skb_dequeue(&x25->fragment_queue)) != NULL) {
64 skb_pull(skbo, (x25->neighbour->extended) ?
65 X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
66 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
67 kfree_skb(skbo);
68 }
69
70 x25->fraglen = 0;
71 }
72
73 skb_set_owner_r(skbn, sk);
74 skb_queue_tail(&sk->sk_receive_queue, skbn);
75 if (!sock_flag(sk, SOCK_DEAD))
76 sk->sk_data_ready(sk, skbn->len);
77
78 return 0;
79 }
80
81 /*
82 * State machine for state 1, Awaiting Call Accepted State.
83 * The handling of the timer(s) is in file x25_timer.c.
84 * Handling of state 0 and connection release is in af_x25.c.
85 */
86 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
87 {
88 struct x25_address source_addr, dest_addr;
89
90 switch (frametype) {
91 case X25_CALL_ACCEPTED: {
92 struct x25_sock *x25 = x25_sk(sk);
93
94 x25_stop_timer(sk);
95 x25->condition = 0x00;
96 x25->vs = 0;
97 x25->va = 0;
98 x25->vr = 0;
99 x25->vl = 0;
100 x25->state = X25_STATE_3;
101 sk->sk_state = TCP_ESTABLISHED;
102 /*
103 * Parse the data in the frame.
104 */
105 skb_pull(skb, X25_STD_MIN_LEN);
106 skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
107 skb_pull(skb,
108 x25_parse_facilities(skb, &x25->facilities,
109 &x25->vc_facil_mask));
110 /*
111 * Copy any Call User Data.
112 */
113 if (skb->len >= 0) {
114 memcpy(x25->calluserdata.cuddata, skb->data,
115 skb->len);
116 x25->calluserdata.cudlength = skb->len;
117 }
118 if (!sock_flag(sk, SOCK_DEAD))
119 sk->sk_state_change(sk);
120 break;
121 }
122 case X25_CLEAR_REQUEST:
123 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
124 x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
125 break;
126
127 default:
128 break;
129 }
130
131 return 0;
132 }
133
134 /*
135 * State machine for state 2, Awaiting Clear Confirmation State.
136 * The handling of the timer(s) is in file x25_timer.c
137 * Handling of state 0 and connection release is in af_x25.c.
138 */
139 static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
140 {
141 switch (frametype) {
142
143 case X25_CLEAR_REQUEST:
144 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
145 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
146 break;
147
148 case X25_CLEAR_CONFIRMATION:
149 x25_disconnect(sk, 0, 0, 0);
150 break;
151
152 default:
153 break;
154 }
155
156 return 0;
157 }
158
159 /*
160 * State machine for state 3, Connected State.
161 * The handling of the timer(s) is in file x25_timer.c
162 * Handling of state 0 and connection release is in af_x25.c.
163 */
164 static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
165 {
166 int queued = 0;
167 int modulus;
168 struct x25_sock *x25 = x25_sk(sk);
169
170 modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
171
172 switch (frametype) {
173
174 case X25_RESET_REQUEST:
175 x25_write_internal(sk, X25_RESET_CONFIRMATION);
176 x25_stop_timer(sk);
177 x25->condition = 0x00;
178 x25->vs = 0;
179 x25->vr = 0;
180 x25->va = 0;
181 x25->vl = 0;
182 x25_requeue_frames(sk);
183 break;
184
185 case X25_CLEAR_REQUEST:
186 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
187 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
188 break;
189
190 case X25_RR:
191 case X25_RNR:
192 if (!x25_validate_nr(sk, nr)) {
193 x25_clear_queues(sk);
194 x25_write_internal(sk, X25_RESET_REQUEST);
195 x25_start_t22timer(sk);
196 x25->condition = 0x00;
197 x25->vs = 0;
198 x25->vr = 0;
199 x25->va = 0;
200 x25->vl = 0;
201 x25->state = X25_STATE_4;
202 } else {
203 x25_frames_acked(sk, nr);
204 if (frametype == X25_RNR) {
205 x25->condition |= X25_COND_PEER_RX_BUSY;
206 } else {
207 x25->condition &= ~X25_COND_PEER_RX_BUSY;
208 }
209 }
210 break;
211
212 case X25_DATA: /* XXX */
213 x25->condition &= ~X25_COND_PEER_RX_BUSY;
214 if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
215 x25_clear_queues(sk);
216 x25_write_internal(sk, X25_RESET_REQUEST);
217 x25_start_t22timer(sk);
218 x25->condition = 0x00;
219 x25->vs = 0;
220 x25->vr = 0;
221 x25->va = 0;
222 x25->vl = 0;
223 x25->state = X25_STATE_4;
224 break;
225 }
226 x25_frames_acked(sk, nr);
227 if (ns == x25->vr) {
228 if (x25_queue_rx_frame(sk, skb, m) == 0) {
229 x25->vr = (x25->vr + 1) % modulus;
230 queued = 1;
231 } else {
232 /* Should never happen */
233 x25_clear_queues(sk);
234 x25_write_internal(sk, X25_RESET_REQUEST);
235 x25_start_t22timer(sk);
236 x25->condition = 0x00;
237 x25->vs = 0;
238 x25->vr = 0;
239 x25->va = 0;
240 x25->vl = 0;
241 x25->state = X25_STATE_4;
242 break;
243 }
244 if (atomic_read(&sk->sk_rmem_alloc) >
245 (sk->sk_rcvbuf / 2))
246 x25->condition |= X25_COND_OWN_RX_BUSY;
247 }
248 /*
249 * If the window is full Ack it immediately, else
250 * start the holdback timer.
251 */
252 if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
253 x25->condition &= ~X25_COND_ACK_PENDING;
254 x25_stop_timer(sk);
255 x25_enquiry_response(sk);
256 } else {
257 x25->condition |= X25_COND_ACK_PENDING;
258 x25_start_t2timer(sk);
259 }
260 break;
261
262 case X25_INTERRUPT_CONFIRMATION:
263 x25->intflag = 0;
264 break;
265
266 case X25_INTERRUPT:
267 if (sock_flag(sk, SOCK_URGINLINE))
268 queued = !sock_queue_rcv_skb(sk, skb);
269 else {
270 skb_set_owner_r(skb, sk);
271 skb_queue_tail(&x25->interrupt_in_queue, skb);
272 queued = 1;
273 }
274 sk_send_sigurg(sk);
275 x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
276 break;
277
278 default:
279 printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
280 break;
281 }
282
283 return queued;
284 }
285
286 /*
287 * State machine for state 4, Awaiting Reset Confirmation State.
288 * The handling of the timer(s) is in file x25_timer.c
289 * Handling of state 0 and connection release is in af_x25.c.
290 */
291 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
292 {
293 switch (frametype) {
294
295 case X25_RESET_REQUEST:
296 x25_write_internal(sk, X25_RESET_CONFIRMATION);
297 case X25_RESET_CONFIRMATION: {
298 struct x25_sock *x25 = x25_sk(sk);
299
300 x25_stop_timer(sk);
301 x25->condition = 0x00;
302 x25->va = 0;
303 x25->vr = 0;
304 x25->vs = 0;
305 x25->vl = 0;
306 x25->state = X25_STATE_3;
307 x25_requeue_frames(sk);
308 break;
309 }
310 case X25_CLEAR_REQUEST:
311 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
312 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
313 break;
314
315 default:
316 break;
317 }
318
319 return 0;
320 }
321
322 /* Higher level upcall for a LAPB frame */
323 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
324 {
325 struct x25_sock *x25 = x25_sk(sk);
326 int queued = 0, frametype, ns, nr, q, d, m;
327
328 if (x25->state == X25_STATE_0)
329 return 0;
330
331 frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
332
333 switch (x25->state) {
334 case X25_STATE_1:
335 queued = x25_state1_machine(sk, skb, frametype);
336 break;
337 case X25_STATE_2:
338 queued = x25_state2_machine(sk, skb, frametype);
339 break;
340 case X25_STATE_3:
341 queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
342 break;
343 case X25_STATE_4:
344 queued = x25_state4_machine(sk, skb, frametype);
345 break;
346 }
347
348 x25_kick(sk);
349
350 return queued;
351 }
352
353 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
354 {
355 int queued = x25_process_rx_frame(sk, skb);
356
357 if (!queued)
358 kfree_skb(skb);
359
360 return 0;
361 }
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