Commit | Line | Data |
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21e3a7bd KS |
1 | /* |
2 | * Copyright (c) University of British Columbia, 1984 | |
3 | * Copyright (c) 1990 The Regents of the University of California. | |
4 | * All rights reserved. | |
5 | * | |
6 | * This code is derived from software contributed to Berkeley by | |
7 | * the Laboratory for Computation Vision and the Computer Science Department | |
8 | * of the University of British Columbia. | |
9 | * | |
10 | * %sccs.include.redist.c% | |
11 | * | |
42963956 | 12 | * @(#)hd_input.c 7.5 (Berkeley) %G% |
21e3a7bd | 13 | */ |
0f9bb9b6 | 14 | |
4507dea2 KS |
15 | #include "param.h" |
16 | #include "systm.h" | |
17 | #include "mbuf.h" | |
18 | #include "domain.h" | |
19 | #include "socket.h" | |
20 | #include "protosw.h" | |
21 | #include "errno.h" | |
22 | #include "time.h" | |
23 | #include "kernel.h" | |
0f9bb9b6 KS |
24 | |
25 | #include "../net/if.h" | |
26 | ||
4507dea2 KS |
27 | #include "hdlc.h" |
28 | #include "hd_var.h" | |
29 | #include "x25.h" | |
0f9bb9b6 KS |
30 | |
31 | /* | |
32 | * HDLC INPUT INTERFACE | |
33 | * | |
34 | * This routine is called when the HDLC physical device has | |
35 | * completed reading a frame. | |
36 | */ | |
37 | ||
38 | hdintr () | |
39 | { | |
40 | register struct mbuf *m; | |
41 | register struct hdcb *hdp; | |
42 | register struct ifnet *ifp; | |
43 | register int s; | |
42963956 | 44 | extern struct ifqueue pkintrq; |
0f9bb9b6 KS |
45 | static struct ifnet *lastifp; |
46 | static struct hdcb *lasthdp; | |
47 | ||
48 | for (;;) { | |
49 | s = splimp (); | |
42963956 | 50 | IF_DEQUEUE (&hdintrq, m); |
0f9bb9b6 KS |
51 | splx (s); |
52 | if (m == 0) | |
53 | break; | |
54 | if (m->m_len < HDHEADERLN) { | |
55 | printf ("hdintr: packet too short (len=%d)\n", | |
56 | m->m_len); | |
57 | m_freem (m); | |
58 | continue; | |
59 | } | |
42963956 KS |
60 | if ((m->m_flags & M_PKTHDR) == 0) |
61 | panic("hdintr"); | |
62 | ifp = m->m_pkthdr.rcvif; | |
0f9bb9b6 KS |
63 | |
64 | /* | |
65 | * look up the appropriate hdlc control block | |
66 | */ | |
67 | ||
68 | if (ifp == lastifp) | |
69 | hdp = lasthdp; | |
70 | else { | |
71 | for (hdp = hdcbhead; hdp; hdp = hdp->hd_next) | |
72 | if (hdp->hd_ifp == ifp) | |
73 | break; | |
74 | if (hdp == 0) { | |
75 | printf ("hdintr: unknown interface %x\n", ifp); | |
76 | m_freem (m); | |
77 | continue; | |
78 | } | |
79 | lastifp = ifp; | |
80 | lasthdp = hdp; | |
81 | } | |
82 | ||
83 | /* Process_rxframe returns FALSE if the frame was NOT queued | |
84 | for the next higher layers. */ | |
85 | if (process_rxframe (hdp, m) == FALSE) | |
86 | m_freem (m); | |
87 | } | |
42963956 KS |
88 | if (pkintrq.ifq_len) |
89 | pkintr (); | |
0f9bb9b6 KS |
90 | } |
91 | ||
92 | process_rxframe (hdp, fbuf) | |
93 | register struct hdcb *hdp; | |
94 | register struct mbuf *fbuf; | |
95 | { | |
96 | register int queued = FALSE, frametype, pf; | |
97 | register struct Hdlc_frame *frame; | |
98 | ||
99 | frame = mtod (fbuf, struct Hdlc_frame *); | |
100 | pf = ((struct Hdlc_iframe *) frame) -> pf; | |
101 | ||
102 | hd_trace (hdp, RX, frame); | |
103 | if (frame -> address != ADDRESS_A && frame -> address != ADDRESS_B) | |
104 | return (queued); | |
105 | ||
106 | switch ((frametype = hd_decode (hdp, frame)) + hdp->hd_state) { | |
107 | case DM + DISC_SENT: | |
108 | case UA + DISC_SENT: | |
109 | /* | |
110 | * Link now closed. Leave timer running | |
111 | * so hd_timer() can periodically check the | |
112 | * status of interface driver flag bit IFF_UP. | |
113 | */ | |
114 | hdp->hd_state = DISCONNECTED; | |
115 | break; | |
116 | ||
117 | case DM + INIT: | |
118 | case UA + INIT: | |
119 | /* | |
120 | * This is a non-standard state change needed for DCEs | |
121 | * that do dynamic link selection. We can't go into the | |
122 | * usual "SEND DM" state because a DM is a SARM in LAP. | |
123 | */ | |
124 | hd_writeinternal (hdp, SABM, POLLOFF); | |
125 | hdp->hd_state = SABM_SENT; | |
126 | SET_TIMER (hdp); | |
127 | break; | |
128 | ||
129 | case SABM + DM_SENT: | |
130 | case SABM + WAIT_SABM: | |
131 | hd_writeinternal (hdp, UA, pf); | |
132 | case UA + SABM_SENT: | |
133 | case UA + WAIT_UA: | |
134 | KILL_TIMER (hdp); | |
135 | hd_initvars (hdp); | |
136 | hdp->hd_state = ABM; | |
137 | hd_message (hdp, "Link level operational"); | |
138 | /* Notify the packet level - to send RESTART. */ | |
139 | (void) pk_ctlinput (PRC_LINKUP, hdp->hd_xcp); | |
140 | break; | |
141 | ||
142 | case SABM + SABM_SENT: | |
143 | /* Got a SABM collision. Acknowledge the remote's SABM | |
144 | via UA but still wait for UA. */ | |
145 | hd_writeinternal (hdp, UA, pf); | |
146 | break; | |
147 | ||
148 | case SABM + ABM: | |
149 | /* Request to reset the link from the remote. */ | |
150 | KILL_TIMER (hdp); | |
151 | hd_message (hdp, "Link reset"); | |
152 | #ifdef HDLCDEBUG | |
153 | hd_dumptrace (hdp); | |
154 | #endif | |
155 | hd_flush (hdp->hd_ifp); | |
156 | hd_writeinternal (hdp, UA, pf); | |
157 | hd_initvars (hdp); | |
158 | (void) pk_ctlinput (PRC_LINKRESET, hdp->hd_xcp); | |
159 | hdp->hd_resets++; | |
160 | break; | |
161 | ||
162 | case SABM + WAIT_UA: | |
163 | hd_writeinternal (hdp, UA, pf); | |
164 | break; | |
165 | ||
166 | case DM + ABM: | |
167 | hd_message (hdp, "DM received: link down"); | |
168 | #ifdef HDLCDEBUG | |
169 | hd_dumptrace (hdp); | |
170 | #endif | |
171 | (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_xcp); | |
172 | hd_flush (hdp->hd_ifp); | |
173 | case DM + DM_SENT: | |
174 | case DM + WAIT_SABM: | |
175 | case DM + WAIT_UA: | |
176 | hd_writeinternal (hdp, SABM, pf); | |
177 | hdp->hd_state = SABM_SENT; | |
178 | SET_TIMER (hdp); | |
179 | break; | |
180 | ||
181 | case DISC + INIT: | |
182 | case DISC + DM_SENT: | |
183 | case DISC + SABM_SENT: | |
184 | /* Note: This is a non-standard state change. */ | |
185 | hd_writeinternal (hdp, UA, pf); | |
186 | hd_writeinternal (hdp, SABM, POLLOFF); | |
187 | hdp->hd_state = SABM_SENT; | |
188 | SET_TIMER (hdp); | |
189 | break; | |
190 | ||
191 | case DISC + WAIT_UA: | |
192 | hd_writeinternal (hdp, DM, pf); | |
193 | SET_TIMER (hdp); | |
194 | hdp->hd_state = DM_SENT; | |
195 | break; | |
196 | ||
197 | case DISC + ABM: | |
198 | hd_message (hdp, "DISC received: link down"); | |
199 | (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_xcp); | |
200 | case DISC + WAIT_SABM: | |
201 | hd_writeinternal (hdp, UA, pf); | |
202 | hdp->hd_state = DM_SENT; | |
203 | SET_TIMER (hdp); | |
204 | break; | |
205 | ||
206 | case UA + ABM: | |
207 | hd_message (hdp, "UA received: link down"); | |
208 | (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_xcp); | |
209 | case UA + WAIT_SABM: | |
210 | hd_writeinternal (hdp, DM, pf); | |
211 | hdp->hd_state = DM_SENT; | |
212 | SET_TIMER (hdp); | |
213 | break; | |
214 | ||
215 | case FRMR + DM_SENT: | |
216 | hd_writeinternal (hdp, SABM, pf); | |
217 | hdp->hd_state = SABM_SENT; | |
218 | SET_TIMER (hdp); | |
219 | break; | |
220 | ||
221 | case FRMR + WAIT_SABM: | |
222 | hd_writeinternal (hdp, DM, pf); | |
223 | hdp->hd_state = DM_SENT; | |
224 | SET_TIMER (hdp); | |
225 | break; | |
226 | ||
227 | case FRMR + ABM: | |
228 | hd_message (hdp, "FRMR received: link down"); | |
229 | (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_xcp); | |
230 | #ifdef HDLCDEBUG | |
231 | hd_dumptrace (hdp); | |
232 | #endif | |
233 | hd_flush (hdp->hd_ifp); | |
234 | hd_writeinternal (hdp, SABM, pf); | |
235 | hdp->hd_state = WAIT_UA; | |
236 | SET_TIMER (hdp); | |
237 | break; | |
238 | ||
239 | case RR + ABM: | |
240 | case RNR + ABM: | |
241 | case REJ + ABM: | |
242 | process_sframe (hdp, (struct Hdlc_sframe *)frame, frametype); | |
243 | break; | |
244 | ||
245 | case IFRAME + ABM: | |
246 | queued = process_iframe (hdp, fbuf, (struct Hdlc_iframe *)frame); | |
247 | break; | |
248 | ||
249 | case IFRAME + SABM_SENT: | |
250 | case RR + SABM_SENT: | |
251 | case RNR + SABM_SENT: | |
252 | case REJ + SABM_SENT: | |
253 | hd_writeinternal (hdp, DM, POLLON); | |
254 | hdp->hd_state = DM_SENT; | |
255 | SET_TIMER (hdp); | |
256 | break; | |
257 | ||
258 | case IFRAME + WAIT_SABM: | |
259 | case RR + WAIT_SABM: | |
260 | case RNR + WAIT_SABM: | |
261 | case REJ + WAIT_SABM: | |
262 | hd_writeinternal (hdp, FRMR, POLLOFF); | |
263 | SET_TIMER (hdp); | |
264 | break; | |
265 | ||
266 | case ILLEGAL + SABM_SENT: | |
267 | hdp->hd_unknown++; | |
268 | hd_writeinternal (hdp, DM, POLLOFF); | |
269 | hdp->hd_state = DM_SENT; | |
270 | SET_TIMER (hdp); | |
271 | break; | |
272 | ||
273 | case ILLEGAL + ABM: | |
274 | hd_message (hdp, "Unknown frame received: link down"); | |
275 | (void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_xcp); | |
276 | case ILLEGAL + WAIT_SABM: | |
277 | hdp->hd_unknown++; | |
278 | #ifdef HDLCDEBUG | |
279 | hd_dumptrace (hdp); | |
280 | #endif | |
281 | hd_writeinternal (hdp, FRMR, POLLOFF); | |
282 | hdp->hd_state = WAIT_SABM; | |
283 | SET_TIMER (hdp); | |
284 | break; | |
285 | } | |
286 | ||
287 | return (queued); | |
288 | } | |
289 | ||
290 | process_iframe (hdp, fbuf, frame) | |
291 | register struct hdcb *hdp; | |
292 | struct mbuf *fbuf; | |
293 | register struct Hdlc_iframe *frame; | |
294 | { | |
295 | register int nr = frame -> nr, | |
296 | ns = frame -> ns, | |
297 | pf = frame -> pf; | |
298 | register int queued = FALSE; | |
299 | ||
300 | /* | |
301 | * Validate the iframe's N(R) value. It's N(R) value must be in | |
302 | * sync with our V(S) value and our "last received nr". | |
303 | */ | |
304 | ||
305 | if (valid_nr (hdp, nr, FALSE) == FALSE) { | |
306 | frame_reject (hdp, Z, frame); | |
307 | return (queued); | |
308 | } | |
309 | ||
310 | ||
311 | /* | |
312 | * This section tests the IFRAME for proper sequence. That is, it's | |
313 | * sequence number N(S) MUST be equal to V(S). | |
314 | */ | |
315 | ||
316 | if (ns != hdp->hd_vr) { | |
317 | hdp->hd_invalid_ns++; | |
318 | if (pf || (hdp->hd_condition & REJ_CONDITION) == 0) { | |
319 | hdp->hd_condition |= REJ_CONDITION; | |
320 | /* | |
321 | * Flush the transmit queue. This is ugly but we | |
322 | * have no choice. A reject response must be | |
323 | * immediately sent to the DCE. Failure to do so | |
324 | * may result in another out of sequence iframe | |
325 | * arriving (and thus sending another reject) | |
326 | * before the first reject is transmitted. This | |
327 | * will cause the DCE to receive two or more | |
328 | * rejects back to back, which must never happen. | |
329 | */ | |
330 | hd_flush (hdp->hd_ifp); | |
331 | hd_writeinternal (hdp, REJ, pf); | |
332 | } | |
333 | return (queued); | |
334 | } | |
335 | hdp->hd_condition &= ~REJ_CONDITION; | |
336 | ||
337 | /* | |
338 | * This section finally tests the IFRAME's sequence number against | |
339 | * the window size (K) and the sequence number of the last frame | |
340 | * we have acknowledged. If the IFRAME is completely correct then | |
341 | * it is queued for the packet level. | |
342 | */ | |
343 | ||
344 | if (ns != (hdp->hd_lasttxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) { | |
345 | hdp->hd_vr = (hdp->hd_vr + 1) % MODULUS; | |
346 | if (pf == 1) { | |
347 | /* Must generate a RR or RNR with final bit on. */ | |
348 | hd_writeinternal (hdp, RR, POLLON); | |
349 | } else | |
350 | /* | |
351 | * Hopefully we can piggyback the RR, if not we will generate | |
352 | * a RR when T3 timer expires. | |
353 | */ | |
354 | if (hdp -> hd_rrtimer == 0) | |
355 | hdp->hd_rrtimer = hd_t3; | |
356 | ||
357 | /* Forward iframe to packet level of X.25. */ | |
b84e7ca8 | 358 | fbuf -> m_data += HDHEADERLN; |
0f9bb9b6 KS |
359 | fbuf -> m_len -= HDHEADERLN; |
360 | #ifdef BSD4_3 | |
361 | fbuf->m_act = 0; /* probably not necessary */ | |
362 | #else | |
363 | { | |
364 | register struct mbuf *m; | |
365 | ||
366 | for (m = fbuf; m -> m_next; m = m -> m_next) | |
367 | m -> m_act = (struct mbuf *) 0; | |
368 | m -> m_act = (struct mbuf *) 1; | |
369 | } | |
370 | #endif | |
371 | pk_input (fbuf, hdp->hd_xcp); | |
372 | queued = TRUE; | |
373 | hd_start (hdp); | |
374 | } else { | |
375 | /* | |
376 | * Here if the remote station has transmitted more iframes then | |
377 | * the number which have been acknowledged plus K. | |
378 | */ | |
379 | hdp->hd_invalid_ns++; | |
380 | frame_reject (hdp, W, frame); | |
381 | } | |
382 | return (queued); | |
383 | } | |
384 | ||
385 | /* | |
386 | * This routine is used to determine if a value (the middle parameter) | |
387 | * is between two other values. The low value is the first parameter | |
388 | * the high value is the last parameter. The routine checks the middle | |
389 | * value to see if it is within the range of the first and last values. | |
390 | * The reason we need this routine is the values are modulo some base | |
391 | * hence a simple test for greater or less than is not sufficient. | |
392 | */ | |
393 | ||
394 | bool | |
395 | range_check (rear, value, front) | |
396 | int rear, | |
397 | value, | |
398 | front; | |
399 | { | |
400 | register bool result = FALSE; | |
401 | ||
402 | if (front > rear) | |
403 | result = (rear <= value) && (value <= front); | |
404 | else | |
405 | result = (rear <= value) || (value <= front); | |
406 | ||
407 | return (result); | |
408 | } | |
409 | ||
410 | /* | |
411 | * This routine handles all the frame reject conditions which can | |
412 | * arise as a result of secondary processing. The frame reject | |
413 | * condition Y (frame length error) are handled elsewhere. | |
414 | */ | |
415 | ||
416 | static | |
417 | frame_reject (hdp, rejectcode, frame) | |
418 | struct hdcb *hdp; | |
419 | struct Hdlc_iframe *frame; | |
420 | { | |
421 | register struct Frmr_frame *frmr = &hd_frmr; | |
422 | ||
423 | frmr -> frmr_control = ((struct Hdlc_frame *) frame) -> control; | |
424 | ||
425 | frmr -> frmr_ns = frame -> ns; | |
426 | frmr -> frmr_f1_0 = 0; | |
427 | frmr -> frmr_nr = frame -> nr; | |
428 | frmr -> frmr_f2_0 = 0; | |
429 | ||
430 | frmr -> frmr_0000 = 0; | |
431 | frmr -> frmr_w = frmr -> frmr_x = frmr -> frmr_y = | |
432 | frmr -> frmr_z = 0; | |
433 | switch (rejectcode) { | |
434 | case Z: | |
435 | frmr -> frmr_z = 1;/* invalid N(R). */ | |
436 | break; | |
437 | ||
438 | case Y: | |
439 | frmr -> frmr_y = 1;/* iframe length error. */ | |
440 | break; | |
441 | ||
442 | case X: | |
443 | frmr -> frmr_x = 1;/* invalid information field. */ | |
444 | frmr -> frmr_w = 1; | |
445 | break; | |
446 | ||
447 | case W: | |
448 | frmr -> frmr_w = 1;/* invalid N(S). */ | |
449 | } | |
450 | ||
451 | hd_writeinternal (hdp, FRMR, POLLOFF); | |
452 | ||
453 | hdp->hd_state = WAIT_SABM; | |
454 | SET_TIMER (hdp); | |
455 | } | |
456 | ||
457 | /* | |
458 | * This procedure is invoked when ever we receive a supervisor | |
459 | * frame such as RR, RNR and REJ. All processing for these | |
460 | * frames is done here. | |
461 | */ | |
462 | ||
463 | process_sframe (hdp, frame, frametype) | |
464 | register struct hdcb *hdp; | |
465 | register struct Hdlc_sframe *frame; | |
466 | int frametype; | |
467 | { | |
468 | register int nr = frame -> nr, pf = frame -> pf, pollbit = 0; | |
469 | ||
470 | if (valid_nr (hdp, nr, pf) == TRUE) { | |
471 | switch (frametype) { | |
472 | case RR: | |
473 | hdp->hd_condition &= ~REMOTE_RNR_CONDITION; | |
474 | break; | |
475 | ||
476 | case RNR: | |
477 | hdp->hd_condition |= REMOTE_RNR_CONDITION; | |
478 | hdp->hd_retxcnt = 0; | |
479 | break; | |
480 | ||
481 | case REJ: | |
482 | hdp->hd_condition &= ~REMOTE_RNR_CONDITION; | |
483 | rej_routine (hdp, nr); | |
484 | } | |
485 | ||
486 | if (pf == 1) { | |
487 | hdp->hd_retxcnt = 0; | |
488 | hdp->hd_condition &= ~TIMER_RECOVERY_CONDITION; | |
489 | ||
42963956 KS |
490 | if (frametype == RR && hdp->hd_lastrxnr == hdp->hd_vs |
491 | && hdp->hd_timer == 0 && hdp->hd_txq.head == 0) | |
492 | hd_writeinternal(hdp, RR, pf); | |
493 | else | |
0f9bb9b6 KS |
494 | /* If any iframes have been queued because of the |
495 | timer condition, transmit then now. */ | |
496 | if (hdp->hd_condition & REMOTE_RNR_CONDITION) { | |
497 | /* Remote is busy or timer condition, so only | |
498 | send one. */ | |
499 | if (hdp->hd_vs != hdp->hd_retxqi) | |
500 | hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], pollbit); | |
501 | } | |
502 | else /* Flush the retransmit list first. */ | |
503 | while (hdp->hd_vs != hdp->hd_retxqi) | |
504 | hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLOFF); | |
505 | } | |
506 | ||
507 | hd_start (hdp); | |
508 | } else | |
509 | frame_reject (hdp, Z, (struct Hdlc_iframe *)frame); /* Invalid N(R). */ | |
510 | } | |
511 | ||
512 | /* | |
513 | * This routine tests the validity of the N(R) which we have received. | |
514 | * If it is ok, then all the iframes which it acknowledges (if any) | |
515 | * will be freed. | |
516 | */ | |
517 | ||
518 | bool | |
519 | valid_nr (hdp, nr, finalbit) | |
520 | register struct hdcb *hdp; | |
521 | register int finalbit; | |
522 | { | |
523 | /* Make sure it really does acknowledge something. */ | |
524 | if (hdp->hd_lastrxnr == nr) | |
525 | return (TRUE); | |
526 | ||
527 | /* | |
528 | * This section validates the frame's N(R) value. It's N(R) value | |
529 | * must be in syncronization with our V(S) value and our "last | |
530 | * received nr" variable. If it is correct then we are able to send | |
531 | * more IFRAME's, else frame reject condition is entered. | |
532 | */ | |
533 | ||
534 | if (range_check (hdp->hd_lastrxnr, nr, hdp->hd_vs) == FALSE) { | |
535 | if ((hdp->hd_condition & TIMER_RECOVERY_CONDITION) && | |
536 | range_check (hdp->hd_vs, nr, hdp->hd_xx) == TRUE) | |
537 | hdp->hd_vs = nr; | |
538 | ||
539 | else { | |
540 | hdp->hd_invalid_nr++; | |
541 | return (FALSE); | |
542 | } | |
543 | } | |
544 | ||
545 | /* | |
546 | * If we get to here, we do have a valid frame but it might be out | |
547 | * of sequence. However, we should still accept the receive state | |
548 | * number N(R) since it has already passed our previous test and it | |
549 | * does acknowledge frames which we are sending. | |
550 | */ | |
551 | ||
552 | KILL_TIMER (hdp); | |
553 | free_iframes (hdp, &nr, finalbit);/* Free all acknowledged iframes */ | |
554 | if (nr != hdp->hd_vs) | |
555 | SET_TIMER (hdp); | |
556 | ||
557 | return (TRUE); | |
558 | } | |
559 | ||
560 | /* | |
561 | * This routine determines how many iframes need to be retransmitted. | |
562 | * It then resets the Send State Variable V(S) to accomplish this. | |
563 | */ | |
564 | ||
565 | static | |
566 | rej_routine (hdp, rejnr) | |
567 | register struct hdcb *hdp; | |
568 | register int rejnr; | |
569 | { | |
570 | register int anchor; | |
571 | ||
572 | /* | |
573 | * Flush the output queue. Any iframes queued for | |
574 | * transmission will be out of sequence. | |
575 | */ | |
576 | ||
577 | hd_flush (hdp->hd_ifp); | |
578 | ||
579 | /* | |
580 | * Determine how many frames should be re-transmitted. In the case | |
581 | * of a normal REJ this should be 1 to K. In the case of a timer | |
582 | * recovery REJ (ie. a REJ with the Final Bit on) this could be 0. | |
583 | */ | |
584 | ||
585 | anchor = hdp->hd_vs; | |
586 | if (hdp->hd_condition & TIMER_RECOVERY_CONDITION) | |
587 | anchor = hdp->hd_xx; | |
588 | ||
589 | anchor = (anchor - rejnr + 8) % MODULUS; | |
590 | ||
591 | if (anchor > 0) { | |
592 | ||
593 | /* There is at least one iframe to retransmit. */ | |
594 | KILL_TIMER (hdp); | |
595 | hdp->hd_vs = rejnr; | |
596 | ||
597 | while (hdp->hd_vs != hdp->hd_retxqi) | |
598 | hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLOFF); | |
599 | ||
600 | } | |
601 | hd_start (hdp); | |
602 | } | |
603 | ||
604 | /* | |
605 | * This routine frees iframes from the retransmit queue. It is called | |
606 | * when a previously written iframe is acknowledged. | |
607 | */ | |
608 | ||
609 | static | |
610 | free_iframes (hdp, nr, finalbit) | |
611 | register struct hdcb *hdp; | |
612 | int *nr; | |
613 | register int finalbit; | |
614 | ||
615 | { | |
616 | register int i, k; | |
617 | ||
618 | /* | |
619 | * We need to do the following because of a funny quirk in the | |
620 | * protocol. This case occures when in Timer recovery condition | |
621 | * we get a N(R) which acknowledges all the outstanding iframes | |
622 | * but with the Final Bit off. In this case we need to save the last | |
623 | * iframe for possible retransmission even though it has already been | |
624 | * acknowledged! | |
625 | */ | |
626 | ||
627 | if ((hdp->hd_condition & TIMER_RECOVERY_CONDITION) && *nr == hdp->hd_xx && finalbit == 0) { | |
628 | *nr = (*nr - 1 + 8) % MODULUS; | |
629 | /* printf ("QUIRK\n"); */ | |
630 | } | |
631 | ||
632 | k = (*nr - hdp->hd_lastrxnr + 8) % MODULUS; | |
633 | ||
634 | /* Loop here freeing all acknowledged iframes. */ | |
635 | for (i = 0; i < k; ++i) { | |
636 | m_freem (hdp->hd_retxq[hdp->hd_lastrxnr]); | |
637 | hdp->hd_retxq[hdp->hd_lastrxnr] = 0; | |
638 | hdp->hd_lastrxnr = (hdp->hd_lastrxnr + 1) % MODULUS; | |
639 | } | |
640 | ||
641 | } |