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1da177e4 LT |
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 | |
f8e1d201 | 6 | * screw up. It might even work. |
1da177e4 LT |
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. | |
f8e1d201 | 20 | * 2000-03-20 Daniela Squassoni Disabling/enabling of facilities |
1da177e4 LT |
21 | * negotiation. |
22 | * 2000-11-10 Henner Eisen Check and reset for out-of-sequence | |
23 | * i-frames. | |
24 | */ | |
25 | ||
5a0e3ad6 | 26 | #include <linux/slab.h> |
1da177e4 LT |
27 | #include <linux/errno.h> |
28 | #include <linux/kernel.h> | |
29 | #include <linux/string.h> | |
30 | #include <linux/skbuff.h> | |
31 | #include <net/sock.h> | |
c752f073 | 32 | #include <net/tcp_states.h> |
1da177e4 LT |
33 | #include <net/x25.h> |
34 | ||
35 | static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more) | |
36 | { | |
37 | struct sk_buff *skbo, *skbn = skb; | |
38 | struct x25_sock *x25 = x25_sk(sk); | |
39 | ||
40 | if (more) { | |
41 | x25->fraglen += skb->len; | |
42 | skb_queue_tail(&x25->fragment_queue, skb); | |
43 | skb_set_owner_r(skb, sk); | |
44 | return 0; | |
45 | } | |
46 | ||
47 | if (!more && x25->fraglen > 0) { /* End of fragment */ | |
48 | int len = x25->fraglen + skb->len; | |
49 | ||
50 | if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){ | |
51 | kfree_skb(skb); | |
52 | return 1; | |
53 | } | |
54 | ||
55 | skb_queue_tail(&x25->fragment_queue, skb); | |
56 | ||
badff6d0 | 57 | skb_reset_transport_header(skbn); |
1da177e4 LT |
58 | |
59 | skbo = skb_dequeue(&x25->fragment_queue); | |
1a4e2d09 ACM |
60 | skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len), |
61 | skbo->len); | |
1da177e4 LT |
62 | kfree_skb(skbo); |
63 | ||
64 | while ((skbo = | |
65 | skb_dequeue(&x25->fragment_queue)) != NULL) { | |
66 | skb_pull(skbo, (x25->neighbour->extended) ? | |
67 | X25_EXT_MIN_LEN : X25_STD_MIN_LEN); | |
1a4e2d09 ACM |
68 | skb_copy_from_linear_data(skbo, |
69 | skb_put(skbn, skbo->len), | |
70 | skbo->len); | |
1da177e4 LT |
71 | kfree_skb(skbo); |
72 | } | |
73 | ||
f8e1d201 | 74 | x25->fraglen = 0; |
1da177e4 LT |
75 | } |
76 | ||
77 | skb_set_owner_r(skbn, sk); | |
78 | skb_queue_tail(&sk->sk_receive_queue, skbn); | |
79 | if (!sock_flag(sk, SOCK_DEAD)) | |
80 | sk->sk_data_ready(sk, skbn->len); | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
85 | /* | |
86 | * State machine for state 1, Awaiting Call Accepted State. | |
87 | * The handling of the timer(s) is in file x25_timer.c. | |
88 | * Handling of state 0 and connection release is in af_x25.c. | |
89 | */ | |
90 | static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
91 | { | |
92 | struct x25_address source_addr, dest_addr; | |
93 | ||
94 | switch (frametype) { | |
95 | case X25_CALL_ACCEPTED: { | |
96 | struct x25_sock *x25 = x25_sk(sk); | |
97 | ||
98 | x25_stop_timer(sk); | |
99 | x25->condition = 0x00; | |
100 | x25->vs = 0; | |
101 | x25->va = 0; | |
102 | x25->vr = 0; | |
103 | x25->vl = 0; | |
104 | x25->state = X25_STATE_3; | |
105 | sk->sk_state = TCP_ESTABLISHED; | |
106 | /* | |
107 | * Parse the data in the frame. | |
108 | */ | |
109 | skb_pull(skb, X25_STD_MIN_LEN); | |
110 | skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr)); | |
111 | skb_pull(skb, | |
112 | x25_parse_facilities(skb, &x25->facilities, | |
a64b7b93 SP |
113 | &x25->dte_facilities, |
114 | &x25->vc_facil_mask)); | |
1da177e4 LT |
115 | /* |
116 | * Copy any Call User Data. | |
117 | */ | |
091bb8ab | 118 | if (skb->len > 0) { |
d626f62b ACM |
119 | skb_copy_from_linear_data(skb, |
120 | x25->calluserdata.cuddata, | |
121 | skb->len); | |
1da177e4 LT |
122 | x25->calluserdata.cudlength = skb->len; |
123 | } | |
124 | if (!sock_flag(sk, SOCK_DEAD)) | |
125 | sk->sk_state_change(sk); | |
126 | break; | |
127 | } | |
128 | case X25_CLEAR_REQUEST: | |
129 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); | |
130 | x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); | |
131 | break; | |
132 | ||
133 | default: | |
134 | break; | |
135 | } | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | /* | |
141 | * State machine for state 2, Awaiting Clear Confirmation State. | |
142 | * The handling of the timer(s) is in file x25_timer.c | |
143 | * Handling of state 0 and connection release is in af_x25.c. | |
144 | */ | |
145 | static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
146 | { | |
147 | switch (frametype) { | |
148 | ||
149 | case X25_CLEAR_REQUEST: | |
150 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); | |
151 | x25_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
152 | break; | |
153 | ||
154 | case X25_CLEAR_CONFIRMATION: | |
155 | x25_disconnect(sk, 0, 0, 0); | |
156 | break; | |
157 | ||
158 | default: | |
159 | break; | |
160 | } | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
165 | /* | |
166 | * State machine for state 3, Connected State. | |
167 | * The handling of the timer(s) is in file x25_timer.c | |
168 | * Handling of state 0 and connection release is in af_x25.c. | |
169 | */ | |
170 | static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) | |
171 | { | |
172 | int queued = 0; | |
173 | int modulus; | |
174 | struct x25_sock *x25 = x25_sk(sk); | |
f8e1d201 | 175 | |
1da177e4 LT |
176 | modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS; |
177 | ||
178 | switch (frametype) { | |
179 | ||
180 | case X25_RESET_REQUEST: | |
181 | x25_write_internal(sk, X25_RESET_CONFIRMATION); | |
182 | x25_stop_timer(sk); | |
183 | x25->condition = 0x00; | |
184 | x25->vs = 0; | |
185 | x25->vr = 0; | |
186 | x25->va = 0; | |
187 | x25->vl = 0; | |
188 | x25_requeue_frames(sk); | |
189 | break; | |
190 | ||
191 | case X25_CLEAR_REQUEST: | |
192 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); | |
193 | x25_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
194 | break; | |
195 | ||
196 | case X25_RR: | |
197 | case X25_RNR: | |
198 | if (!x25_validate_nr(sk, nr)) { | |
199 | x25_clear_queues(sk); | |
200 | x25_write_internal(sk, X25_RESET_REQUEST); | |
201 | x25_start_t22timer(sk); | |
202 | x25->condition = 0x00; | |
203 | x25->vs = 0; | |
204 | x25->vr = 0; | |
205 | x25->va = 0; | |
206 | x25->vl = 0; | |
207 | x25->state = X25_STATE_4; | |
208 | } else { | |
209 | x25_frames_acked(sk, nr); | |
210 | if (frametype == X25_RNR) { | |
211 | x25->condition |= X25_COND_PEER_RX_BUSY; | |
212 | } else { | |
213 | x25->condition &= ~X25_COND_PEER_RX_BUSY; | |
214 | } | |
215 | } | |
216 | break; | |
217 | ||
218 | case X25_DATA: /* XXX */ | |
219 | x25->condition &= ~X25_COND_PEER_RX_BUSY; | |
220 | if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) { | |
221 | x25_clear_queues(sk); | |
222 | x25_write_internal(sk, X25_RESET_REQUEST); | |
223 | x25_start_t22timer(sk); | |
224 | x25->condition = 0x00; | |
225 | x25->vs = 0; | |
226 | x25->vr = 0; | |
227 | x25->va = 0; | |
228 | x25->vl = 0; | |
229 | x25->state = X25_STATE_4; | |
230 | break; | |
231 | } | |
232 | x25_frames_acked(sk, nr); | |
233 | if (ns == x25->vr) { | |
234 | if (x25_queue_rx_frame(sk, skb, m) == 0) { | |
235 | x25->vr = (x25->vr + 1) % modulus; | |
236 | queued = 1; | |
237 | } else { | |
238 | /* Should never happen */ | |
239 | x25_clear_queues(sk); | |
240 | x25_write_internal(sk, X25_RESET_REQUEST); | |
241 | x25_start_t22timer(sk); | |
242 | x25->condition = 0x00; | |
243 | x25->vs = 0; | |
244 | x25->vr = 0; | |
245 | x25->va = 0; | |
246 | x25->vl = 0; | |
247 | x25->state = X25_STATE_4; | |
248 | break; | |
249 | } | |
250 | if (atomic_read(&sk->sk_rmem_alloc) > | |
6bf1574e | 251 | (sk->sk_rcvbuf >> 1)) |
1da177e4 LT |
252 | x25->condition |= X25_COND_OWN_RX_BUSY; |
253 | } | |
254 | /* | |
255 | * If the window is full Ack it immediately, else | |
256 | * start the holdback timer. | |
257 | */ | |
258 | if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) { | |
259 | x25->condition &= ~X25_COND_ACK_PENDING; | |
260 | x25_stop_timer(sk); | |
261 | x25_enquiry_response(sk); | |
262 | } else { | |
263 | x25->condition |= X25_COND_ACK_PENDING; | |
264 | x25_start_t2timer(sk); | |
265 | } | |
266 | break; | |
267 | ||
268 | case X25_INTERRUPT_CONFIRMATION: | |
269 | x25->intflag = 0; | |
270 | break; | |
271 | ||
272 | case X25_INTERRUPT: | |
273 | if (sock_flag(sk, SOCK_URGINLINE)) | |
274 | queued = !sock_queue_rcv_skb(sk, skb); | |
275 | else { | |
276 | skb_set_owner_r(skb, sk); | |
277 | skb_queue_tail(&x25->interrupt_in_queue, skb); | |
278 | queued = 1; | |
279 | } | |
280 | sk_send_sigurg(sk); | |
281 | x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION); | |
282 | break; | |
283 | ||
284 | default: | |
285 | printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype); | |
286 | break; | |
287 | } | |
288 | ||
289 | return queued; | |
290 | } | |
291 | ||
292 | /* | |
293 | * State machine for state 4, Awaiting Reset Confirmation State. | |
294 | * The handling of the timer(s) is in file x25_timer.c | |
295 | * Handling of state 0 and connection release is in af_x25.c. | |
296 | */ | |
297 | static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
298 | { | |
299 | switch (frametype) { | |
300 | ||
301 | case X25_RESET_REQUEST: | |
302 | x25_write_internal(sk, X25_RESET_CONFIRMATION); | |
303 | case X25_RESET_CONFIRMATION: { | |
304 | struct x25_sock *x25 = x25_sk(sk); | |
305 | ||
306 | x25_stop_timer(sk); | |
307 | x25->condition = 0x00; | |
308 | x25->va = 0; | |
309 | x25->vr = 0; | |
310 | x25->vs = 0; | |
311 | x25->vl = 0; | |
312 | x25->state = X25_STATE_3; | |
313 | x25_requeue_frames(sk); | |
314 | break; | |
315 | } | |
316 | case X25_CLEAR_REQUEST: | |
317 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); | |
318 | x25_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
319 | break; | |
320 | ||
321 | default: | |
322 | break; | |
323 | } | |
324 | ||
325 | return 0; | |
326 | } | |
327 | ||
328 | /* Higher level upcall for a LAPB frame */ | |
329 | int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb) | |
330 | { | |
331 | struct x25_sock *x25 = x25_sk(sk); | |
332 | int queued = 0, frametype, ns, nr, q, d, m; | |
333 | ||
334 | if (x25->state == X25_STATE_0) | |
335 | return 0; | |
336 | ||
337 | frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m); | |
338 | ||
339 | switch (x25->state) { | |
340 | case X25_STATE_1: | |
341 | queued = x25_state1_machine(sk, skb, frametype); | |
342 | break; | |
343 | case X25_STATE_2: | |
344 | queued = x25_state2_machine(sk, skb, frametype); | |
345 | break; | |
346 | case X25_STATE_3: | |
347 | queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m); | |
348 | break; | |
349 | case X25_STATE_4: | |
350 | queued = x25_state4_machine(sk, skb, frametype); | |
351 | break; | |
352 | } | |
353 | ||
354 | x25_kick(sk); | |
355 | ||
356 | return queued; | |
357 | } | |
358 | ||
359 | int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
360 | { | |
361 | int queued = x25_process_rx_frame(sk, skb); | |
362 | ||
363 | if (!queued) | |
364 | kfree_skb(skb); | |
365 | ||
366 | return 0; | |
367 | } |