1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Author	Karsten Keil <kkeil@novell.com>
5  *
6  * Copyright 2008  by Karsten Keil <kkeil@novell.com>
7  */
8 
9 #include <linux/gfp.h>
10 #include <linux/module.h>
11 #include <linux/mISDNhw.h>
12 
13 static void
dchannel_bh(struct work_struct * ws)14 dchannel_bh(struct work_struct *ws)
15 {
16 	struct dchannel	*dch  = container_of(ws, struct dchannel, workq);
17 	struct sk_buff	*skb;
18 	int		err;
19 
20 	if (test_and_clear_bit(FLG_RECVQUEUE, &dch->Flags)) {
21 		while ((skb = skb_dequeue(&dch->rqueue))) {
22 			if (likely(dch->dev.D.peer)) {
23 				err = dch->dev.D.recv(dch->dev.D.peer, skb);
24 				if (err)
25 					dev_kfree_skb(skb);
26 			} else
27 				dev_kfree_skb(skb);
28 		}
29 	}
30 	if (test_and_clear_bit(FLG_PHCHANGE, &dch->Flags)) {
31 		if (dch->phfunc)
32 			dch->phfunc(dch);
33 	}
34 }
35 
36 static void
bchannel_bh(struct work_struct * ws)37 bchannel_bh(struct work_struct *ws)
38 {
39 	struct bchannel	*bch  = container_of(ws, struct bchannel, workq);
40 	struct sk_buff	*skb;
41 	int		err;
42 
43 	if (test_and_clear_bit(FLG_RECVQUEUE, &bch->Flags)) {
44 		while ((skb = skb_dequeue(&bch->rqueue))) {
45 			bch->rcount--;
46 			if (likely(bch->ch.peer)) {
47 				err = bch->ch.recv(bch->ch.peer, skb);
48 				if (err)
49 					dev_kfree_skb(skb);
50 			} else
51 				dev_kfree_skb(skb);
52 		}
53 	}
54 }
55 
56 int
mISDN_initdchannel(struct dchannel * ch,int maxlen,void * phf)57 mISDN_initdchannel(struct dchannel *ch, int maxlen, void *phf)
58 {
59 	test_and_set_bit(FLG_HDLC, &ch->Flags);
60 	ch->maxlen = maxlen;
61 	ch->hw = NULL;
62 	ch->rx_skb = NULL;
63 	ch->tx_skb = NULL;
64 	ch->tx_idx = 0;
65 	ch->phfunc = phf;
66 	skb_queue_head_init(&ch->squeue);
67 	skb_queue_head_init(&ch->rqueue);
68 	INIT_LIST_HEAD(&ch->dev.bchannels);
69 	INIT_WORK(&ch->workq, dchannel_bh);
70 	return 0;
71 }
72 EXPORT_SYMBOL(mISDN_initdchannel);
73 
74 int
mISDN_initbchannel(struct bchannel * ch,unsigned short maxlen,unsigned short minlen)75 mISDN_initbchannel(struct bchannel *ch, unsigned short maxlen,
76 		   unsigned short minlen)
77 {
78 	ch->Flags = 0;
79 	ch->minlen = minlen;
80 	ch->next_minlen = minlen;
81 	ch->init_minlen = minlen;
82 	ch->maxlen = maxlen;
83 	ch->next_maxlen = maxlen;
84 	ch->init_maxlen = maxlen;
85 	ch->hw = NULL;
86 	ch->rx_skb = NULL;
87 	ch->tx_skb = NULL;
88 	ch->tx_idx = 0;
89 	skb_queue_head_init(&ch->rqueue);
90 	ch->rcount = 0;
91 	ch->next_skb = NULL;
92 	INIT_WORK(&ch->workq, bchannel_bh);
93 	return 0;
94 }
95 EXPORT_SYMBOL(mISDN_initbchannel);
96 
97 int
mISDN_freedchannel(struct dchannel * ch)98 mISDN_freedchannel(struct dchannel *ch)
99 {
100 	if (ch->tx_skb) {
101 		dev_kfree_skb(ch->tx_skb);
102 		ch->tx_skb = NULL;
103 	}
104 	if (ch->rx_skb) {
105 		dev_kfree_skb(ch->rx_skb);
106 		ch->rx_skb = NULL;
107 	}
108 	skb_queue_purge(&ch->squeue);
109 	skb_queue_purge(&ch->rqueue);
110 	flush_work(&ch->workq);
111 	return 0;
112 }
113 EXPORT_SYMBOL(mISDN_freedchannel);
114 
115 void
mISDN_clear_bchannel(struct bchannel * ch)116 mISDN_clear_bchannel(struct bchannel *ch)
117 {
118 	if (ch->tx_skb) {
119 		dev_kfree_skb(ch->tx_skb);
120 		ch->tx_skb = NULL;
121 	}
122 	ch->tx_idx = 0;
123 	if (ch->rx_skb) {
124 		dev_kfree_skb(ch->rx_skb);
125 		ch->rx_skb = NULL;
126 	}
127 	if (ch->next_skb) {
128 		dev_kfree_skb(ch->next_skb);
129 		ch->next_skb = NULL;
130 	}
131 	test_and_clear_bit(FLG_TX_BUSY, &ch->Flags);
132 	test_and_clear_bit(FLG_TX_NEXT, &ch->Flags);
133 	test_and_clear_bit(FLG_ACTIVE, &ch->Flags);
134 	test_and_clear_bit(FLG_FILLEMPTY, &ch->Flags);
135 	test_and_clear_bit(FLG_TX_EMPTY, &ch->Flags);
136 	test_and_clear_bit(FLG_RX_OFF, &ch->Flags);
137 	ch->dropcnt = 0;
138 	ch->minlen = ch->init_minlen;
139 	ch->next_minlen = ch->init_minlen;
140 	ch->maxlen = ch->init_maxlen;
141 	ch->next_maxlen = ch->init_maxlen;
142 	skb_queue_purge(&ch->rqueue);
143 	ch->rcount = 0;
144 }
145 EXPORT_SYMBOL(mISDN_clear_bchannel);
146 
147 void
mISDN_freebchannel(struct bchannel * ch)148 mISDN_freebchannel(struct bchannel *ch)
149 {
150 	cancel_work_sync(&ch->workq);
151 	mISDN_clear_bchannel(ch);
152 }
153 EXPORT_SYMBOL(mISDN_freebchannel);
154 
155 int
mISDN_ctrl_bchannel(struct bchannel * bch,struct mISDN_ctrl_req * cq)156 mISDN_ctrl_bchannel(struct bchannel *bch, struct mISDN_ctrl_req *cq)
157 {
158 	int ret = 0;
159 
160 	switch (cq->op) {
161 	case MISDN_CTRL_GETOP:
162 		cq->op = MISDN_CTRL_RX_BUFFER | MISDN_CTRL_FILL_EMPTY |
163 			 MISDN_CTRL_RX_OFF;
164 		break;
165 	case MISDN_CTRL_FILL_EMPTY:
166 		if (cq->p1) {
167 			memset(bch->fill, cq->p2 & 0xff, MISDN_BCH_FILL_SIZE);
168 			test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
169 		} else {
170 			test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
171 		}
172 		break;
173 	case MISDN_CTRL_RX_OFF:
174 		/* read back dropped byte count */
175 		cq->p2 = bch->dropcnt;
176 		if (cq->p1)
177 			test_and_set_bit(FLG_RX_OFF, &bch->Flags);
178 		else
179 			test_and_clear_bit(FLG_RX_OFF, &bch->Flags);
180 		bch->dropcnt = 0;
181 		break;
182 	case MISDN_CTRL_RX_BUFFER:
183 		if (cq->p2 > MISDN_CTRL_RX_SIZE_IGNORE)
184 			bch->next_maxlen = cq->p2;
185 		if (cq->p1 > MISDN_CTRL_RX_SIZE_IGNORE)
186 			bch->next_minlen = cq->p1;
187 		/* we return the old values */
188 		cq->p1 = bch->minlen;
189 		cq->p2 = bch->maxlen;
190 		break;
191 	default:
192 		pr_info("mISDN unhandled control %x operation\n", cq->op);
193 		ret = -EINVAL;
194 		break;
195 	}
196 	return ret;
197 }
198 EXPORT_SYMBOL(mISDN_ctrl_bchannel);
199 
200 static inline u_int
get_sapi_tei(u_char * p)201 get_sapi_tei(u_char *p)
202 {
203 	u_int	sapi, tei;
204 
205 	sapi = *p >> 2;
206 	tei = p[1] >> 1;
207 	return sapi | (tei << 8);
208 }
209 
210 void
recv_Dchannel(struct dchannel * dch)211 recv_Dchannel(struct dchannel *dch)
212 {
213 	struct mISDNhead *hh;
214 
215 	if (dch->rx_skb->len < 2) { /* at least 2 for sapi / tei */
216 		dev_kfree_skb(dch->rx_skb);
217 		dch->rx_skb = NULL;
218 		return;
219 	}
220 	hh = mISDN_HEAD_P(dch->rx_skb);
221 	hh->prim = PH_DATA_IND;
222 	hh->id = get_sapi_tei(dch->rx_skb->data);
223 	skb_queue_tail(&dch->rqueue, dch->rx_skb);
224 	dch->rx_skb = NULL;
225 	schedule_event(dch, FLG_RECVQUEUE);
226 }
227 EXPORT_SYMBOL(recv_Dchannel);
228 
229 void
recv_Echannel(struct dchannel * ech,struct dchannel * dch)230 recv_Echannel(struct dchannel *ech, struct dchannel *dch)
231 {
232 	struct mISDNhead *hh;
233 
234 	if (ech->rx_skb->len < 2) { /* at least 2 for sapi / tei */
235 		dev_kfree_skb(ech->rx_skb);
236 		ech->rx_skb = NULL;
237 		return;
238 	}
239 	hh = mISDN_HEAD_P(ech->rx_skb);
240 	hh->prim = PH_DATA_E_IND;
241 	hh->id = get_sapi_tei(ech->rx_skb->data);
242 	skb_queue_tail(&dch->rqueue, ech->rx_skb);
243 	ech->rx_skb = NULL;
244 	schedule_event(dch, FLG_RECVQUEUE);
245 }
246 EXPORT_SYMBOL(recv_Echannel);
247 
248 void
recv_Bchannel(struct bchannel * bch,unsigned int id,bool force)249 recv_Bchannel(struct bchannel *bch, unsigned int id, bool force)
250 {
251 	struct mISDNhead *hh;
252 
253 	/* if allocation did fail upper functions still may call us */
254 	if (unlikely(!bch->rx_skb))
255 		return;
256 	if (unlikely(!bch->rx_skb->len)) {
257 		/* we have no data to send - this may happen after recovery
258 		 * from overflow or too small allocation.
259 		 * We need to free the buffer here */
260 		dev_kfree_skb(bch->rx_skb);
261 		bch->rx_skb = NULL;
262 	} else {
263 		if (test_bit(FLG_TRANSPARENT, &bch->Flags) &&
264 		    (bch->rx_skb->len < bch->minlen) && !force)
265 				return;
266 		hh = mISDN_HEAD_P(bch->rx_skb);
267 		hh->prim = PH_DATA_IND;
268 		hh->id = id;
269 		if (bch->rcount >= 64) {
270 			printk(KERN_WARNING
271 			       "B%d receive queue overflow - flushing!\n",
272 			       bch->nr);
273 			skb_queue_purge(&bch->rqueue);
274 		}
275 		bch->rcount++;
276 		skb_queue_tail(&bch->rqueue, bch->rx_skb);
277 		bch->rx_skb = NULL;
278 		schedule_event(bch, FLG_RECVQUEUE);
279 	}
280 }
281 EXPORT_SYMBOL(recv_Bchannel);
282 
283 void
recv_Dchannel_skb(struct dchannel * dch,struct sk_buff * skb)284 recv_Dchannel_skb(struct dchannel *dch, struct sk_buff *skb)
285 {
286 	skb_queue_tail(&dch->rqueue, skb);
287 	schedule_event(dch, FLG_RECVQUEUE);
288 }
289 EXPORT_SYMBOL(recv_Dchannel_skb);
290 
291 void
recv_Bchannel_skb(struct bchannel * bch,struct sk_buff * skb)292 recv_Bchannel_skb(struct bchannel *bch, struct sk_buff *skb)
293 {
294 	if (bch->rcount >= 64) {
295 		printk(KERN_WARNING "B-channel %p receive queue overflow, "
296 		       "flushing!\n", bch);
297 		skb_queue_purge(&bch->rqueue);
298 		bch->rcount = 0;
299 	}
300 	bch->rcount++;
301 	skb_queue_tail(&bch->rqueue, skb);
302 	schedule_event(bch, FLG_RECVQUEUE);
303 }
304 EXPORT_SYMBOL(recv_Bchannel_skb);
305 
306 static void
confirm_Dsend(struct dchannel * dch)307 confirm_Dsend(struct dchannel *dch)
308 {
309 	struct sk_buff	*skb;
310 
311 	skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(dch->tx_skb),
312 			       0, NULL, GFP_ATOMIC);
313 	if (!skb) {
314 		printk(KERN_ERR "%s: no skb id %x\n", __func__,
315 		       mISDN_HEAD_ID(dch->tx_skb));
316 		return;
317 	}
318 	skb_queue_tail(&dch->rqueue, skb);
319 	schedule_event(dch, FLG_RECVQUEUE);
320 }
321 
322 int
get_next_dframe(struct dchannel * dch)323 get_next_dframe(struct dchannel *dch)
324 {
325 	dch->tx_idx = 0;
326 	dch->tx_skb = skb_dequeue(&dch->squeue);
327 	if (dch->tx_skb) {
328 		confirm_Dsend(dch);
329 		return 1;
330 	}
331 	dch->tx_skb = NULL;
332 	test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
333 	return 0;
334 }
335 EXPORT_SYMBOL(get_next_dframe);
336 
337 static void
confirm_Bsend(struct bchannel * bch)338 confirm_Bsend(struct bchannel *bch)
339 {
340 	struct sk_buff	*skb;
341 
342 	if (bch->rcount >= 64) {
343 		printk(KERN_WARNING "B-channel %p receive queue overflow, "
344 		       "flushing!\n", bch);
345 		skb_queue_purge(&bch->rqueue);
346 		bch->rcount = 0;
347 	}
348 	skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(bch->tx_skb),
349 			       0, NULL, GFP_ATOMIC);
350 	if (!skb) {
351 		printk(KERN_ERR "%s: no skb id %x\n", __func__,
352 		       mISDN_HEAD_ID(bch->tx_skb));
353 		return;
354 	}
355 	bch->rcount++;
356 	skb_queue_tail(&bch->rqueue, skb);
357 	schedule_event(bch, FLG_RECVQUEUE);
358 }
359 
360 int
get_next_bframe(struct bchannel * bch)361 get_next_bframe(struct bchannel *bch)
362 {
363 	bch->tx_idx = 0;
364 	if (test_bit(FLG_TX_NEXT, &bch->Flags)) {
365 		bch->tx_skb = bch->next_skb;
366 		if (bch->tx_skb) {
367 			bch->next_skb = NULL;
368 			test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
369 			/* confirm imediately to allow next data */
370 			confirm_Bsend(bch);
371 			return 1;
372 		} else {
373 			test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
374 			printk(KERN_WARNING "B TX_NEXT without skb\n");
375 		}
376 	}
377 	bch->tx_skb = NULL;
378 	test_and_clear_bit(FLG_TX_BUSY, &bch->Flags);
379 	return 0;
380 }
381 EXPORT_SYMBOL(get_next_bframe);
382 
383 void
queue_ch_frame(struct mISDNchannel * ch,u_int pr,int id,struct sk_buff * skb)384 queue_ch_frame(struct mISDNchannel *ch, u_int pr, int id, struct sk_buff *skb)
385 {
386 	struct mISDNhead *hh;
387 
388 	if (!skb) {
389 		_queue_data(ch, pr, id, 0, NULL, GFP_ATOMIC);
390 	} else {
391 		if (ch->peer) {
392 			hh = mISDN_HEAD_P(skb);
393 			hh->prim = pr;
394 			hh->id = id;
395 			if (!ch->recv(ch->peer, skb))
396 				return;
397 		}
398 		dev_kfree_skb(skb);
399 	}
400 }
401 EXPORT_SYMBOL(queue_ch_frame);
402 
403 int
dchannel_senddata(struct dchannel * ch,struct sk_buff * skb)404 dchannel_senddata(struct dchannel *ch, struct sk_buff *skb)
405 {
406 	/* check oversize */
407 	if (skb->len <= 0) {
408 		printk(KERN_WARNING "%s: skb too small\n", __func__);
409 		return -EINVAL;
410 	}
411 	if (skb->len > ch->maxlen) {
412 		printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
413 		       __func__, skb->len, ch->maxlen);
414 		return -EINVAL;
415 	}
416 	/* HW lock must be obtained */
417 	if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
418 		skb_queue_tail(&ch->squeue, skb);
419 		return 0;
420 	} else {
421 		/* write to fifo */
422 		ch->tx_skb = skb;
423 		ch->tx_idx = 0;
424 		return 1;
425 	}
426 }
427 EXPORT_SYMBOL(dchannel_senddata);
428 
429 int
bchannel_senddata(struct bchannel * ch,struct sk_buff * skb)430 bchannel_senddata(struct bchannel *ch, struct sk_buff *skb)
431 {
432 
433 	/* check oversize */
434 	if (skb->len <= 0) {
435 		printk(KERN_WARNING "%s: skb too small\n", __func__);
436 		return -EINVAL;
437 	}
438 	if (skb->len > ch->maxlen) {
439 		printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
440 		       __func__, skb->len, ch->maxlen);
441 		return -EINVAL;
442 	}
443 	/* HW lock must be obtained */
444 	/* check for pending next_skb */
445 	if (ch->next_skb) {
446 		printk(KERN_WARNING
447 		       "%s: next_skb exist ERROR (skb->len=%d next_skb->len=%d)\n",
448 		       __func__, skb->len, ch->next_skb->len);
449 		return -EBUSY;
450 	}
451 	if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
452 		test_and_set_bit(FLG_TX_NEXT, &ch->Flags);
453 		ch->next_skb = skb;
454 		return 0;
455 	} else {
456 		/* write to fifo */
457 		ch->tx_skb = skb;
458 		ch->tx_idx = 0;
459 		confirm_Bsend(ch);
460 		return 1;
461 	}
462 }
463 EXPORT_SYMBOL(bchannel_senddata);
464 
465 /* The function allocates a new receive skb on demand with a size for the
466  * requirements of the current protocol. It returns the tailroom of the
467  * receive skb or an error.
468  */
469 int
bchannel_get_rxbuf(struct bchannel * bch,int reqlen)470 bchannel_get_rxbuf(struct bchannel *bch, int reqlen)
471 {
472 	int len;
473 
474 	if (bch->rx_skb) {
475 		len = skb_tailroom(bch->rx_skb);
476 		if (len < reqlen) {
477 			pr_warn("B%d no space for %d (only %d) bytes\n",
478 				bch->nr, reqlen, len);
479 			if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
480 				/* send what we have now and try a new buffer */
481 				recv_Bchannel(bch, 0, true);
482 			} else {
483 				/* on HDLC we have to drop too big frames */
484 				return -EMSGSIZE;
485 			}
486 		} else {
487 			return len;
488 		}
489 	}
490 	/* update current min/max length first */
491 	if (unlikely(bch->maxlen != bch->next_maxlen))
492 		bch->maxlen = bch->next_maxlen;
493 	if (unlikely(bch->minlen != bch->next_minlen))
494 		bch->minlen = bch->next_minlen;
495 	if (unlikely(reqlen > bch->maxlen))
496 		return -EMSGSIZE;
497 	if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
498 		if (reqlen >= bch->minlen) {
499 			len = reqlen;
500 		} else {
501 			len = 2 * bch->minlen;
502 			if (len > bch->maxlen)
503 				len = bch->maxlen;
504 		}
505 	} else {
506 		/* with HDLC we do not know the length yet */
507 		len = bch->maxlen;
508 	}
509 	bch->rx_skb = mI_alloc_skb(len, GFP_ATOMIC);
510 	if (!bch->rx_skb) {
511 		pr_warn("B%d receive no memory for %d bytes\n", bch->nr, len);
512 		len = -ENOMEM;
513 	}
514 	return len;
515 }
516 EXPORT_SYMBOL(bchannel_get_rxbuf);
517