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*/
1 /*
2 * 802.2 Class 2 LLC service.
3 */
4
5
6 int llc_rx_adm(struct sock *sk,struct sk_buff *skb, int type, int cmd, int pf, int nr, int ns)
/* ![[next]](../icons/right.png)
![[first]](../icons/n_first.png)
![[top]](../icons/top.png)
*/
7 {
8 if(type==CMD)
9 {
10 if(cmd==DISC)
11 send_response(sk,DM|pf);
12 else if(cmd==SABM)
13 {
14 if(sk->state!=TCP_LISTEN)
15 send_response(sk. DM|pf);
16 else
17 {
18 sk=ll_rx_accept(sk);
19 if(sk!=NULL)
20 {
21 send_response(sk, UA|pf);
22 sk->llc.vs=0;
23 sk->llc.vr=0;
24 sk->llc.p_flag=0;
25 sk->llc.remote_busy=0;
26 llc_state(sk,LLC_NORMAL);
27 }
28 }
29 }
30 else if(pf)
31 send_response(sk, DM|PF);
32 }
33 return 0;
34 }
35
36 int llc_rx_setup(struct sock *sk, struct sk_buff *skb, int type, int cmd, int pf, int nr, int ns)
/* ![[previous]](../icons/left.png)
*/
37 {
38 if(type==CMD)
39 {
40 if(cmd==SABM)
41 {
42 sk->llc.vs=0;
43 sk->llc.vr=0;
44 send_response(sk, UA|pf);
45 }
46 if(cmd==DISC)
47 {
48 send_response(sk, DM|pf);
49 llc_error(sk,ECONNRESET);
50 llc_state(sk, LLC_ADM);
51 }
52 }
53 else
54 {
55 if(cmd==UA && pf==sk->llc.p_flag)
56 {
57 del_timer(&sk->llc.t1);
58 sk->llc.vs=0;
59 llc_update_p_flag(sk,pf);
60 llc_state(sk,LLC_NORMAL);
61 }
62 if(cmd==DM)
63 {
64 llc_error(sk, ECONNRESET);
65 llc_state(sk, LLC_ADM);
66 }
67 }
68 }
69
70 int llc_rx_reset(struct sock *sk, struct sk_buff *skb, int type, int cmd, int pf, int nr, int ns)
/* */
71 {
72 if(type==CMD)
73 {
74 if(cmd==SABM)
75 {
76 sk->llc.vr=0;
77 sk->llc.vs=0;
78 send_response(sk, UA|pf);
79 }
80 else if(cmd==DISC)
81 {
82 if(sk->llc.cause_flag==1)
83 llc_shutdown(sk,SHUTDOWN_MASK);
84 else
85 llc_eror(sk, ECONNREFUSED);
86 send_response(sk, DM|pf);
87 llc_state(sk, LLC_ADM);
88 }
89 }
90 else
91 {
92 if(cmd==UA)
93 {
94 if(sk->llc.p_flag==pf)
95 {
96 del_timer(&sk->llc.t1);
97 sk->llc.vs=0;
98 sk->llc.vr=0;
99 llc_update_p_flag(sk,pf);
100 llc_confirm_reset(sk, sk->llc.cause_flag);
101 sk->llc.remote_busy=0;
102 llc_state(sk, LLC_NORMAL);
103 }
104 }
105 if(cmd==DM)
106 { /* Should check cause_flag */
107 llc_shutdown(sk, SHUTDOWN_MASK);
108 llc_state(sk, LLC_ADM);
109 }
110 }
111 return 0;
112 }
113
114 int llc_rx_d_conn(struct sock *sk, struct sk_buff *skb, int type, int cmd, int pf, int nr, int ns)
/* */
115 {
116 if(type==CMD)
117 {
118 if(cmd==SABM)
119 {
120 llc_error(sk, ECONNRESET);
121 llc_state(sk, ADM);
122 }
123 else if(cmd==DISC)
124 {
125 send_response(UA|pf);
126 llc_state(sk, LLC_D_CONN);
127 }
128 else if(pf)
129 send_response(sk, DM|PF);
130 }
131 else
132 {
133 if(cmd==UA && pf==sk->llc.p_flag)
134 {
135 del_timer(&sk->llc.t1);
136 llc_state(sk, ADM);
137 llc_confirm_reset(sk, sk->llc.cause_flag);
138 }
139 if(cmd==DM)
140 {
141 del_timer(&sk->llc.t1);
142 /*if(sk->llc.cause_flag)*/
143 llc_shutdown(sk, SHUTDOWN_MASK);
144 }
145
146 }
147 return 0;
148 }
149
150 int llc_rx_error(struct sock *sk, struct sk_buff *skb, int type, int cmd, int pf, int nr, int ns)
/* */
151 {
152 if(type==CMD)
153 {
154 if(cmd==SABM)
155 {
156 sk->llc.vs=0;
157 sk->llc.vr=0;
158 send_response(sk, UA|pf);
159 llc_error(sk,ECONNRESET);
160 sk->llc.p_flag=0;
161 sk->llc.remote_busy=0;
162 llc_state(sk, LLC_NORMAL);
163 }
164 else if(cmd==DISC)
165 {
166 send_response(sk, UA|pf);
167 llc_shutdown(sk, SHUTDOWN_MASK);
168 llc_state(sk, LLC_ADM);
169 }
170 else
171 llc_resend_frmr_rsp(sk,pf);
172 }
173 else
174 {
175 if(cmd==DM)
176 {
177 llc_error(sk, ECONNRESET);
178 del_timer(&sk->llc.t1);
179 llc_state(sk, LLC_ADM);
180 }
181 if(cmd==FRMR)
182 {
183 send_command(sk, SABM);
184 sk->llc.p_flag=pf;
185 llc_start_t1();
186 sk->llc.retry_count=0;
187 sk->llc.cause_flag=0;
188 llc_error(sk, EPROTO);
189 llc_state(sk, LLC_RESET);
190 }
191 }
192 }
193
194
195 /*
196 * Subroutine for handling the shared cases of the data modes.
197 */
198
199 int llc_rx_nr_shared(struct sock *sk, struct sk_buff *skb, int type, int cmd, int pf, int nr, int ns)
/* */
200 {
201 if(type==CMD)
202 {
203 if(cmd==SABM)
204 {
205 /*
206 * Optional reset processing. We decline resets.
207 */
208 send_response(sk,DM|pf);
209 llc_error(sk, ECONNRESET);
210 llc_state(sk, LLC_ADM);
211 }
212 else if(cmd==DISC)
213 {
214 send_response(sk,UA|pf);
215 llc_state(sk, LLC_ADM);
216 llc_shutdown(sk, SHUTDOWN_MASK);
217 }
218 /*
219 * We only ever use windows of 7, so there is no illegal NR/NS value
220 * otherwise we would FRMR here and go to ERROR state
221 */
222 else if(cmd==ILLEGAL)
223 {
224 llc_send_frmr_response(sk, ILLEGAL_TYPE,pf);
225 llc_state(sk, LLC_ERROR);
226 llc_error(sk, EPROTO);
227 }
228 else
229 /*
230 * Not covered by general rule
231 */
232 return 0;
233 }
234 else
235 {
236 /*
237 * We close on errors
238 */
239 if(cmd==FRMR)
240 {
241 send_command(sk, DM|pf);
242 sk->llc.p_flag=pf;
243 llc_start_t1(sk);
244 llc_error(sk, EPROTO);
245 sk->llc.cause_flag=0;
246 llc_state(sk, LLC_D_CONN):
247 }
248 else if(cmd==DM)
249 {
250 llc_state(sk, LLC_ADM);
251 llc_error(sk, ECONNREFUSED);
252 }
253 /*
254 * We always use a window of 7 so can't get I resp
255 * with invalid NS, or any resp with invalid NR. If
256 * we add this they do the same as..
257 */
258 else if(cmd==UA)
259 {
260 llc_send_frmr_response(sk, UNEXPECTED_CONTROL, pf);
261 llc_state(sk, LLC_ERROR);
262 llc_error(sk, EPROTO);
263 }
264 else if(pf==1 && sk->llc.p_flag==0)
265 {
266 llc_send_frmr_response(sk, UNEXPECTED_RESPONSE, pf);
267 llc_state(sk, LLC_ERROR);
268 llc_error(sk, EPROTO);
269 }
270 else if(cmd==ILLEGAL)
271 {
272 llc_send_frmr_response(sk, ILLEGAL_TYPE,pf);
273 llc_state(sk, LLC_ERROR);
274 llc_error(sk, EPROTO);
275 }
276 else
277 /*
278 * Not covered by general rule
279 */
280 return 0
281 }
282 /*
283 * Processed.
284 */
285 return 1;
286 }
287
288 int llc_rx_normal(struct sock *sk, struct sk_buff *skb, int type, int cmd, int pf, int nr, int ns)
/* ![[last]](../icons/n_last.png)
*/
289 {
290 if(llc_rx_nr_shared(sk, skb, type, cmd, pf, nr, ns))
291 return 0;
292 if(cmd==I)
293 {
294 if(llc_invalid_ns(sk,ns))
295 {
296 if((type==RESP && sk->llc.p_flag==pf)||(type==CMD && pf==0 && sk->llc.p_flag==0))
297 {
298 llc_command(sk, REJ|PF);
299 llc_ack_frames(sk,nr); /* Ack frames and update N(R) */
300 sk->llc.p_flag=PF;
301 llc_state(sk, LLC_REJECT);
302 sk->llc.retry_count=0;
303 llc_start_t1(sk);
304 sk->llc.remote_busy=0;
305 }
306 else if((type==CMD && !pf && sk->llc.p_flag==1) || (type==RESP && !pf && sk->llc.p_flag==1))
307 {
308 if(type==CMD)
309 llc_response(sk, REJ);
310 else
311 llc_command(sk, REJ);
312 llc_ack_frames(sk,nr);
313 sk->llc.retry_count=0;
314 llc_state(sk, LLC_REJECT);
315 llc_start_t1(sk);
316 }
317 else if(pf && type==CMD)
318 {
319 llc_response(sk, REJ|PF);
320 llc_ack_frames(sk,nr);
321 sk->llc.retry_count=0;
322 llc_start_t1(sk);
323 }
324 }
325 else
326 {
327 /*
328 * Valid I frame cases
329 */
330
331 if(sk->llc.p_flag==pf && !(type==CMD && pf))
332 {
333 sk->llc.vr=(sk->llc.vr+1)&7;
334 llc_queue_rr_cmd(sk, PF);
335 sk->llc.retry_count=0;
336 llc_start_t1(sk);
337 sk->llc.p_flag=1;
338 llc_ack_frames(sk,nr);
339 sk->llc.remote_busy=0;
340 }
341 else if(sk->ppc.p_flag!=pf)
342 {
343 sk->llc.vr=(sk->llc.vr+1)&7;
344 if(type==CMD)
345 llc_queue_rr_resp(sk, 0);
346 else
347 llc_queue_rr_cmd(sk, 0);
348 if(sk->llc.nr!=nr)
349 {
350 llc_ack_frames(sk,nr);
351 llc_reset_t1(sk);
352 }
353 }
354 else if(pf)
355 {
356 sk->llc.vr=(sk->llc.vr+1)&7;
357 llc_queue_rr_resp(sk,PF);
358 if(sk->llc.nr!=nr)
359 {
360 llc_ack_frames(sk,nr);
361 llc_reset_t1(sk);
362 }
363 }
364 llc_queue_data(sk,skb);
365 return 1;
366 }
367 }
368 else if(cmd==RR||cmd==RNR)
369 {
370 if(type==CMD || (type==RESP && (!pf || pf==1 && sk->llc.p_flag==1)))
371 {
372 llc_update_p_flag(sk,pf);
373 if(sk->llc.nr!=nr)
374 {
375 llc_ack_frames(sk,nr);
376 llc_reset_t1(sk);
377 }
378 if(cmd==RR)
379 sk->llc.remote_busy=0;
380 else
381 { sk->llc.remote_busy=1;
382 if(!llc_t1_running(sk))
383 llc_start_t1(sk);
384 }
385 }
386 else if(type==cmd && pf)
387 {
388 if(cmd==RR)
389 llc_queue_rr_resp(sk,PF);
390 else
391 {
392 send_response(sk, RR|PF);
393 if(!llc_t1_running(sk))
394 llc_start_t1(sk);
395 }
396 if(sk->llc.nr!=nr)
397 {
398 llc_ack_frames(sk,nr);
399 llc_reset_t1(sk);
400 }
401 if(cmd==RR)
402 sk->llc.remote_busy=0;
403 else
404 sk->llc.remote_busy=1;
405 }
406 }
407 else if(cmd==REJ)
408 {
409
410 }
411 }
412
![[bottom]](../icons/n_bottom.png){kind=icon}
*/