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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 | |
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> | |
c752f073 | 31 | #include <net/tcp_states.h> |
1da177e4 LT |
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 | } |