xref: /linux/net/can/j1939/transport.c (revision 0e9b70c1e3623fa110fb6be553e644524228ef60)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2010-2011 EIA Electronics,
3 //                         Kurt Van Dijck <kurt.van.dijck@eia.be>
4 // Copyright (c) 2018 Protonic,
5 //                         Robin van der Gracht <robin@protonic.nl>
6 // Copyright (c) 2017-2019 Pengutronix,
7 //                         Marc Kleine-Budde <kernel@pengutronix.de>
8 // Copyright (c) 2017-2019 Pengutronix,
9 //                         Oleksij Rempel <kernel@pengutronix.de>
10 
11 #include <linux/can/skb.h>
12 
13 #include "j1939-priv.h"
14 
15 #define J1939_XTP_TX_RETRY_LIMIT 100
16 
17 #define J1939_ETP_PGN_CTL 0xc800
18 #define J1939_ETP_PGN_DAT 0xc700
19 #define J1939_TP_PGN_CTL 0xec00
20 #define J1939_TP_PGN_DAT 0xeb00
21 
22 #define J1939_TP_CMD_RTS 0x10
23 #define J1939_TP_CMD_CTS 0x11
24 #define J1939_TP_CMD_EOMA 0x13
25 #define J1939_TP_CMD_BAM 0x20
26 #define J1939_TP_CMD_ABORT 0xff
27 
28 #define J1939_ETP_CMD_RTS 0x14
29 #define J1939_ETP_CMD_CTS 0x15
30 #define J1939_ETP_CMD_DPO 0x16
31 #define J1939_ETP_CMD_EOMA 0x17
32 #define J1939_ETP_CMD_ABORT 0xff
33 
34 enum j1939_xtp_abort {
35 	J1939_XTP_NO_ABORT = 0,
36 	J1939_XTP_ABORT_BUSY = 1,
37 	/* Already in one or more connection managed sessions and
38 	 * cannot support another.
39 	 *
40 	 * EALREADY:
41 	 * Operation already in progress
42 	 */
43 
44 	J1939_XTP_ABORT_RESOURCE = 2,
45 	/* System resources were needed for another task so this
46 	 * connection managed session was terminated.
47 	 *
48 	 * EMSGSIZE:
49 	 * The socket type requires that message be sent atomically,
50 	 * and the size of the message to be sent made this
51 	 * impossible.
52 	 */
53 
54 	J1939_XTP_ABORT_TIMEOUT = 3,
55 	/* A timeout occurred and this is the connection abort to
56 	 * close the session.
57 	 *
58 	 * EHOSTUNREACH:
59 	 * The destination host cannot be reached (probably because
60 	 * the host is down or a remote router cannot reach it).
61 	 */
62 
63 	J1939_XTP_ABORT_GENERIC = 4,
64 	/* CTS messages received when data transfer is in progress
65 	 *
66 	 * EBADMSG:
67 	 * Not a data message
68 	 */
69 
70 	J1939_XTP_ABORT_FAULT = 5,
71 	/* Maximal retransmit request limit reached
72 	 *
73 	 * ENOTRECOVERABLE:
74 	 * State not recoverable
75 	 */
76 
77 	J1939_XTP_ABORT_UNEXPECTED_DATA = 6,
78 	/* Unexpected data transfer packet
79 	 *
80 	 * ENOTCONN:
81 	 * Transport endpoint is not connected
82 	 */
83 
84 	J1939_XTP_ABORT_BAD_SEQ = 7,
85 	/* Bad sequence number (and software is not able to recover)
86 	 *
87 	 * EILSEQ:
88 	 * Illegal byte sequence
89 	 */
90 
91 	J1939_XTP_ABORT_DUP_SEQ = 8,
92 	/* Duplicate sequence number (and software is not able to
93 	 * recover)
94 	 */
95 
96 	J1939_XTP_ABORT_EDPO_UNEXPECTED = 9,
97 	/* Unexpected EDPO packet (ETP) or Message size > 1785 bytes
98 	 * (TP)
99 	 */
100 
101 	J1939_XTP_ABORT_BAD_EDPO_PGN = 10,
102 	/* Unexpected EDPO PGN (PGN in EDPO is bad) */
103 
104 	J1939_XTP_ABORT_EDPO_OUTOF_CTS = 11,
105 	/* EDPO number of packets is greater than CTS */
106 
107 	J1939_XTP_ABORT_BAD_EDPO_OFFSET = 12,
108 	/* Bad EDPO offset */
109 
110 	J1939_XTP_ABORT_OTHER_DEPRECATED = 13,
111 	/* Deprecated. Use 250 instead (Any other reason)  */
112 
113 	J1939_XTP_ABORT_ECTS_UNXPECTED_PGN = 14,
114 	/* Unexpected ECTS PGN (PGN in ECTS is bad) */
115 
116 	J1939_XTP_ABORT_ECTS_TOO_BIG = 15,
117 	/* ECTS requested packets exceeds message size */
118 
119 	J1939_XTP_ABORT_OTHER = 250,
120 	/* Any other reason (if a Connection Abort reason is
121 	 * identified that is not listed in the table use code 250)
122 	 */
123 };
124 
125 static unsigned int j1939_tp_block = 255;
126 static unsigned int j1939_tp_packet_delay;
127 static unsigned int j1939_tp_padding = 1;
128 
129 /* helpers */
130 static const char *j1939_xtp_abort_to_str(enum j1939_xtp_abort abort)
131 {
132 	switch (abort) {
133 	case J1939_XTP_ABORT_BUSY:
134 		return "Already in one or more connection managed sessions and cannot support another.";
135 	case J1939_XTP_ABORT_RESOURCE:
136 		return "System resources were needed for another task so this connection managed session was terminated.";
137 	case J1939_XTP_ABORT_TIMEOUT:
138 		return "A timeout occurred and this is the connection abort to close the session.";
139 	case J1939_XTP_ABORT_GENERIC:
140 		return "CTS messages received when data transfer is in progress";
141 	case J1939_XTP_ABORT_FAULT:
142 		return "Maximal retransmit request limit reached";
143 	case J1939_XTP_ABORT_UNEXPECTED_DATA:
144 		return "Unexpected data transfer packet";
145 	case J1939_XTP_ABORT_BAD_SEQ:
146 		return "Bad sequence number (and software is not able to recover)";
147 	case J1939_XTP_ABORT_DUP_SEQ:
148 		return "Duplicate sequence number (and software is not able to recover)";
149 	case J1939_XTP_ABORT_EDPO_UNEXPECTED:
150 		return "Unexpected EDPO packet (ETP) or Message size > 1785 bytes (TP)";
151 	case J1939_XTP_ABORT_BAD_EDPO_PGN:
152 		return "Unexpected EDPO PGN (PGN in EDPO is bad)";
153 	case J1939_XTP_ABORT_EDPO_OUTOF_CTS:
154 		return "EDPO number of packets is greater than CTS";
155 	case J1939_XTP_ABORT_BAD_EDPO_OFFSET:
156 		return "Bad EDPO offset";
157 	case J1939_XTP_ABORT_OTHER_DEPRECATED:
158 		return "Deprecated. Use 250 instead (Any other reason)";
159 	case J1939_XTP_ABORT_ECTS_UNXPECTED_PGN:
160 		return "Unexpected ECTS PGN (PGN in ECTS is bad)";
161 	case J1939_XTP_ABORT_ECTS_TOO_BIG:
162 		return "ECTS requested packets exceeds message size";
163 	case J1939_XTP_ABORT_OTHER:
164 		return "Any other reason (if a Connection Abort reason is identified that is not listed in the table use code 250)";
165 	default:
166 		return "<unknown>";
167 	}
168 }
169 
170 static int j1939_xtp_abort_to_errno(struct j1939_priv *priv,
171 				    enum j1939_xtp_abort abort)
172 {
173 	int err;
174 
175 	switch (abort) {
176 	case J1939_XTP_NO_ABORT:
177 		WARN_ON_ONCE(abort == J1939_XTP_NO_ABORT);
178 		err = 0;
179 		break;
180 	case J1939_XTP_ABORT_BUSY:
181 		err = EALREADY;
182 		break;
183 	case J1939_XTP_ABORT_RESOURCE:
184 		err = EMSGSIZE;
185 		break;
186 	case J1939_XTP_ABORT_TIMEOUT:
187 		err = EHOSTUNREACH;
188 		break;
189 	case J1939_XTP_ABORT_GENERIC:
190 		err = EBADMSG;
191 		break;
192 	case J1939_XTP_ABORT_FAULT:
193 		err = ENOTRECOVERABLE;
194 		break;
195 	case J1939_XTP_ABORT_UNEXPECTED_DATA:
196 		err = ENOTCONN;
197 		break;
198 	case J1939_XTP_ABORT_BAD_SEQ:
199 		err = EILSEQ;
200 		break;
201 	case J1939_XTP_ABORT_DUP_SEQ:
202 		err = EPROTO;
203 		break;
204 	case J1939_XTP_ABORT_EDPO_UNEXPECTED:
205 		err = EPROTO;
206 		break;
207 	case J1939_XTP_ABORT_BAD_EDPO_PGN:
208 		err = EPROTO;
209 		break;
210 	case J1939_XTP_ABORT_EDPO_OUTOF_CTS:
211 		err = EPROTO;
212 		break;
213 	case J1939_XTP_ABORT_BAD_EDPO_OFFSET:
214 		err = EPROTO;
215 		break;
216 	case J1939_XTP_ABORT_OTHER_DEPRECATED:
217 		err = EPROTO;
218 		break;
219 	case J1939_XTP_ABORT_ECTS_UNXPECTED_PGN:
220 		err = EPROTO;
221 		break;
222 	case J1939_XTP_ABORT_ECTS_TOO_BIG:
223 		err = EPROTO;
224 		break;
225 	case J1939_XTP_ABORT_OTHER:
226 		err = EPROTO;
227 		break;
228 	default:
229 		netdev_warn(priv->ndev, "Unknown abort code %i", abort);
230 		err = EPROTO;
231 	}
232 
233 	return err;
234 }
235 
236 static inline void j1939_session_list_lock(struct j1939_priv *priv)
237 {
238 	spin_lock_bh(&priv->active_session_list_lock);
239 }
240 
241 static inline void j1939_session_list_unlock(struct j1939_priv *priv)
242 {
243 	spin_unlock_bh(&priv->active_session_list_lock);
244 }
245 
246 void j1939_session_get(struct j1939_session *session)
247 {
248 	kref_get(&session->kref);
249 }
250 
251 /* session completion functions */
252 static void __j1939_session_drop(struct j1939_session *session)
253 {
254 	if (!session->transmission)
255 		return;
256 
257 	j1939_sock_pending_del(session->sk);
258 	sock_put(session->sk);
259 }
260 
261 static void j1939_session_destroy(struct j1939_session *session)
262 {
263 	struct sk_buff *skb;
264 
265 	if (session->transmission) {
266 		if (session->err)
267 			j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ABORT);
268 		else
269 			j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ACK);
270 	} else if (session->err) {
271 			j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
272 	}
273 
274 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
275 
276 	WARN_ON_ONCE(!list_empty(&session->sk_session_queue_entry));
277 	WARN_ON_ONCE(!list_empty(&session->active_session_list_entry));
278 
279 	while ((skb = skb_dequeue(&session->skb_queue)) != NULL) {
280 		/* drop ref taken in j1939_session_skb_queue() */
281 		skb_unref(skb);
282 		kfree_skb(skb);
283 	}
284 	__j1939_session_drop(session);
285 	j1939_priv_put(session->priv);
286 	kfree(session);
287 }
288 
289 static void __j1939_session_release(struct kref *kref)
290 {
291 	struct j1939_session *session = container_of(kref, struct j1939_session,
292 						     kref);
293 
294 	j1939_session_destroy(session);
295 }
296 
297 void j1939_session_put(struct j1939_session *session)
298 {
299 	kref_put(&session->kref, __j1939_session_release);
300 }
301 
302 static void j1939_session_txtimer_cancel(struct j1939_session *session)
303 {
304 	if (hrtimer_cancel(&session->txtimer))
305 		j1939_session_put(session);
306 }
307 
308 static void j1939_session_rxtimer_cancel(struct j1939_session *session)
309 {
310 	if (hrtimer_cancel(&session->rxtimer))
311 		j1939_session_put(session);
312 }
313 
314 void j1939_session_timers_cancel(struct j1939_session *session)
315 {
316 	j1939_session_txtimer_cancel(session);
317 	j1939_session_rxtimer_cancel(session);
318 }
319 
320 static inline bool j1939_cb_is_broadcast(const struct j1939_sk_buff_cb *skcb)
321 {
322 	return (!skcb->addr.dst_name && (skcb->addr.da == 0xff));
323 }
324 
325 static void j1939_session_skb_drop_old(struct j1939_session *session)
326 {
327 	struct sk_buff *do_skb;
328 	struct j1939_sk_buff_cb *do_skcb;
329 	unsigned int offset_start;
330 	unsigned long flags;
331 
332 	if (skb_queue_len(&session->skb_queue) < 2)
333 		return;
334 
335 	offset_start = session->pkt.tx_acked * 7;
336 
337 	spin_lock_irqsave(&session->skb_queue.lock, flags);
338 	do_skb = skb_peek(&session->skb_queue);
339 	do_skcb = j1939_skb_to_cb(do_skb);
340 
341 	if ((do_skcb->offset + do_skb->len) < offset_start) {
342 		__skb_unlink(do_skb, &session->skb_queue);
343 		/* drop ref taken in j1939_session_skb_queue() */
344 		skb_unref(do_skb);
345 		spin_unlock_irqrestore(&session->skb_queue.lock, flags);
346 
347 		kfree_skb(do_skb);
348 	} else {
349 		spin_unlock_irqrestore(&session->skb_queue.lock, flags);
350 	}
351 }
352 
353 void j1939_session_skb_queue(struct j1939_session *session,
354 			     struct sk_buff *skb)
355 {
356 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
357 	struct j1939_priv *priv = session->priv;
358 
359 	j1939_ac_fixup(priv, skb);
360 
361 	if (j1939_address_is_unicast(skcb->addr.da) &&
362 	    priv->ents[skcb->addr.da].nusers)
363 		skcb->flags |= J1939_ECU_LOCAL_DST;
364 
365 	skcb->flags |= J1939_ECU_LOCAL_SRC;
366 
367 	skb_get(skb);
368 	skb_queue_tail(&session->skb_queue, skb);
369 }
370 
371 static struct
372 sk_buff *j1939_session_skb_get_by_offset(struct j1939_session *session,
373 					 unsigned int offset_start)
374 {
375 	struct j1939_priv *priv = session->priv;
376 	struct j1939_sk_buff_cb *do_skcb;
377 	struct sk_buff *skb = NULL;
378 	struct sk_buff *do_skb;
379 	unsigned long flags;
380 
381 	spin_lock_irqsave(&session->skb_queue.lock, flags);
382 	skb_queue_walk(&session->skb_queue, do_skb) {
383 		do_skcb = j1939_skb_to_cb(do_skb);
384 
385 		if (offset_start >= do_skcb->offset &&
386 		    offset_start < (do_skcb->offset + do_skb->len)) {
387 			skb = do_skb;
388 		}
389 	}
390 
391 	if (skb)
392 		skb_get(skb);
393 
394 	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
395 
396 	if (!skb)
397 		netdev_dbg(priv->ndev, "%s: 0x%p: no skb found for start: %i, queue size: %i\n",
398 			   __func__, session, offset_start,
399 			   skb_queue_len(&session->skb_queue));
400 
401 	return skb;
402 }
403 
404 static struct sk_buff *j1939_session_skb_get(struct j1939_session *session)
405 {
406 	unsigned int offset_start;
407 
408 	offset_start = session->pkt.dpo * 7;
409 	return j1939_session_skb_get_by_offset(session, offset_start);
410 }
411 
412 /* see if we are receiver
413  * returns 0 for broadcasts, although we will receive them
414  */
415 static inline int j1939_tp_im_receiver(const struct j1939_sk_buff_cb *skcb)
416 {
417 	return skcb->flags & J1939_ECU_LOCAL_DST;
418 }
419 
420 /* see if we are sender */
421 static inline int j1939_tp_im_transmitter(const struct j1939_sk_buff_cb *skcb)
422 {
423 	return skcb->flags & J1939_ECU_LOCAL_SRC;
424 }
425 
426 /* see if we are involved as either receiver or transmitter */
427 static int j1939_tp_im_involved(const struct j1939_sk_buff_cb *skcb, bool swap)
428 {
429 	if (swap)
430 		return j1939_tp_im_receiver(skcb);
431 	else
432 		return j1939_tp_im_transmitter(skcb);
433 }
434 
435 static int j1939_tp_im_involved_anydir(struct j1939_sk_buff_cb *skcb)
436 {
437 	return skcb->flags & (J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
438 }
439 
440 /* extract pgn from flow-ctl message */
441 static inline pgn_t j1939_xtp_ctl_to_pgn(const u8 *dat)
442 {
443 	pgn_t pgn;
444 
445 	pgn = (dat[7] << 16) | (dat[6] << 8) | (dat[5] << 0);
446 	if (j1939_pgn_is_pdu1(pgn))
447 		pgn &= 0xffff00;
448 	return pgn;
449 }
450 
451 static inline unsigned int j1939_tp_ctl_to_size(const u8 *dat)
452 {
453 	return (dat[2] << 8) + (dat[1] << 0);
454 }
455 
456 static inline unsigned int j1939_etp_ctl_to_packet(const u8 *dat)
457 {
458 	return (dat[4] << 16) | (dat[3] << 8) | (dat[2] << 0);
459 }
460 
461 static inline unsigned int j1939_etp_ctl_to_size(const u8 *dat)
462 {
463 	return (dat[4] << 24) | (dat[3] << 16) |
464 		(dat[2] << 8) | (dat[1] << 0);
465 }
466 
467 /* find existing session:
468  * reverse: swap cb's src & dst
469  * there is no problem with matching broadcasts, since
470  * broadcasts (no dst, no da) would never call this
471  * with reverse == true
472  */
473 static bool j1939_session_match(struct j1939_addr *se_addr,
474 				struct j1939_addr *sk_addr, bool reverse)
475 {
476 	if (se_addr->type != sk_addr->type)
477 		return false;
478 
479 	if (reverse) {
480 		if (se_addr->src_name) {
481 			if (se_addr->src_name != sk_addr->dst_name)
482 				return false;
483 		} else if (se_addr->sa != sk_addr->da) {
484 			return false;
485 		}
486 
487 		if (se_addr->dst_name) {
488 			if (se_addr->dst_name != sk_addr->src_name)
489 				return false;
490 		} else if (se_addr->da != sk_addr->sa) {
491 			return false;
492 		}
493 	} else {
494 		if (se_addr->src_name) {
495 			if (se_addr->src_name != sk_addr->src_name)
496 				return false;
497 		} else if (se_addr->sa != sk_addr->sa) {
498 			return false;
499 		}
500 
501 		if (se_addr->dst_name) {
502 			if (se_addr->dst_name != sk_addr->dst_name)
503 				return false;
504 		} else if (se_addr->da != sk_addr->da) {
505 			return false;
506 		}
507 	}
508 
509 	return true;
510 }
511 
512 static struct
513 j1939_session *j1939_session_get_by_addr_locked(struct j1939_priv *priv,
514 						struct list_head *root,
515 						struct j1939_addr *addr,
516 						bool reverse, bool transmitter)
517 {
518 	struct j1939_session *session;
519 
520 	lockdep_assert_held(&priv->active_session_list_lock);
521 
522 	list_for_each_entry(session, root, active_session_list_entry) {
523 		j1939_session_get(session);
524 		if (j1939_session_match(&session->skcb.addr, addr, reverse) &&
525 		    session->transmission == transmitter)
526 			return session;
527 		j1939_session_put(session);
528 	}
529 
530 	return NULL;
531 }
532 
533 static struct
534 j1939_session *j1939_session_get_simple(struct j1939_priv *priv,
535 					struct sk_buff *skb)
536 {
537 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
538 	struct j1939_session *session;
539 
540 	lockdep_assert_held(&priv->active_session_list_lock);
541 
542 	list_for_each_entry(session, &priv->active_session_list,
543 			    active_session_list_entry) {
544 		j1939_session_get(session);
545 		if (session->skcb.addr.type == J1939_SIMPLE &&
546 		    session->tskey == skcb->tskey && session->sk == skb->sk)
547 			return session;
548 		j1939_session_put(session);
549 	}
550 
551 	return NULL;
552 }
553 
554 static struct
555 j1939_session *j1939_session_get_by_addr(struct j1939_priv *priv,
556 					 struct j1939_addr *addr,
557 					 bool reverse, bool transmitter)
558 {
559 	struct j1939_session *session;
560 
561 	j1939_session_list_lock(priv);
562 	session = j1939_session_get_by_addr_locked(priv,
563 						   &priv->active_session_list,
564 						   addr, reverse, transmitter);
565 	j1939_session_list_unlock(priv);
566 
567 	return session;
568 }
569 
570 static void j1939_skbcb_swap(struct j1939_sk_buff_cb *skcb)
571 {
572 	u8 tmp = 0;
573 
574 	swap(skcb->addr.dst_name, skcb->addr.src_name);
575 	swap(skcb->addr.da, skcb->addr.sa);
576 
577 	/* swap SRC and DST flags, leave other untouched */
578 	if (skcb->flags & J1939_ECU_LOCAL_SRC)
579 		tmp |= J1939_ECU_LOCAL_DST;
580 	if (skcb->flags & J1939_ECU_LOCAL_DST)
581 		tmp |= J1939_ECU_LOCAL_SRC;
582 	skcb->flags &= ~(J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
583 	skcb->flags |= tmp;
584 }
585 
586 static struct
587 sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv,
588 			     const struct j1939_sk_buff_cb *re_skcb,
589 			     bool ctl,
590 			     bool swap_src_dst)
591 {
592 	struct sk_buff *skb;
593 	struct j1939_sk_buff_cb *skcb;
594 
595 	skb = alloc_skb(sizeof(struct can_frame) + sizeof(struct can_skb_priv),
596 			GFP_ATOMIC);
597 	if (unlikely(!skb))
598 		return ERR_PTR(-ENOMEM);
599 
600 	skb->dev = priv->ndev;
601 	can_skb_reserve(skb);
602 	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
603 	can_skb_prv(skb)->skbcnt = 0;
604 	/* reserve CAN header */
605 	skb_reserve(skb, offsetof(struct can_frame, data));
606 
607 	memcpy(skb->cb, re_skcb, sizeof(skb->cb));
608 	skcb = j1939_skb_to_cb(skb);
609 	if (swap_src_dst)
610 		j1939_skbcb_swap(skcb);
611 
612 	if (ctl) {
613 		if (skcb->addr.type == J1939_ETP)
614 			skcb->addr.pgn = J1939_ETP_PGN_CTL;
615 		else
616 			skcb->addr.pgn = J1939_TP_PGN_CTL;
617 	} else {
618 		if (skcb->addr.type == J1939_ETP)
619 			skcb->addr.pgn = J1939_ETP_PGN_DAT;
620 		else
621 			skcb->addr.pgn = J1939_TP_PGN_DAT;
622 	}
623 
624 	return skb;
625 }
626 
627 /* TP transmit packet functions */
628 static int j1939_tp_tx_dat(struct j1939_session *session,
629 			   const u8 *dat, int len)
630 {
631 	struct j1939_priv *priv = session->priv;
632 	struct sk_buff *skb;
633 
634 	skb = j1939_tp_tx_dat_new(priv, &session->skcb,
635 				  false, false);
636 	if (IS_ERR(skb))
637 		return PTR_ERR(skb);
638 
639 	skb_put_data(skb, dat, len);
640 	if (j1939_tp_padding && len < 8)
641 		memset(skb_put(skb, 8 - len), 0xff, 8 - len);
642 
643 	return j1939_send_one(priv, skb);
644 }
645 
646 static int j1939_xtp_do_tx_ctl(struct j1939_priv *priv,
647 			       const struct j1939_sk_buff_cb *re_skcb,
648 			       bool swap_src_dst, pgn_t pgn, const u8 *dat)
649 {
650 	struct sk_buff *skb;
651 	u8 *skdat;
652 
653 	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
654 		return 0;
655 
656 	skb = j1939_tp_tx_dat_new(priv, re_skcb, true, swap_src_dst);
657 	if (IS_ERR(skb))
658 		return PTR_ERR(skb);
659 
660 	skdat = skb_put(skb, 8);
661 	memcpy(skdat, dat, 5);
662 	skdat[5] = (pgn >> 0);
663 	skdat[6] = (pgn >> 8);
664 	skdat[7] = (pgn >> 16);
665 
666 	return j1939_send_one(priv, skb);
667 }
668 
669 static inline int j1939_tp_tx_ctl(struct j1939_session *session,
670 				  bool swap_src_dst, const u8 *dat)
671 {
672 	struct j1939_priv *priv = session->priv;
673 
674 	return j1939_xtp_do_tx_ctl(priv, &session->skcb,
675 				   swap_src_dst,
676 				   session->skcb.addr.pgn, dat);
677 }
678 
679 static int j1939_xtp_tx_abort(struct j1939_priv *priv,
680 			      const struct j1939_sk_buff_cb *re_skcb,
681 			      bool swap_src_dst,
682 			      enum j1939_xtp_abort err,
683 			      pgn_t pgn)
684 {
685 	u8 dat[5];
686 
687 	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
688 		return 0;
689 
690 	memset(dat, 0xff, sizeof(dat));
691 	dat[0] = J1939_TP_CMD_ABORT;
692 	dat[1] = err;
693 	return j1939_xtp_do_tx_ctl(priv, re_skcb, swap_src_dst, pgn, dat);
694 }
695 
696 void j1939_tp_schedule_txtimer(struct j1939_session *session, int msec)
697 {
698 	j1939_session_get(session);
699 	hrtimer_start(&session->txtimer, ms_to_ktime(msec),
700 		      HRTIMER_MODE_REL_SOFT);
701 }
702 
703 static inline void j1939_tp_set_rxtimeout(struct j1939_session *session,
704 					  int msec)
705 {
706 	j1939_session_rxtimer_cancel(session);
707 	j1939_session_get(session);
708 	hrtimer_start(&session->rxtimer, ms_to_ktime(msec),
709 		      HRTIMER_MODE_REL_SOFT);
710 }
711 
712 static int j1939_session_tx_rts(struct j1939_session *session)
713 {
714 	u8 dat[8];
715 	int ret;
716 
717 	memset(dat, 0xff, sizeof(dat));
718 
719 	dat[1] = (session->total_message_size >> 0);
720 	dat[2] = (session->total_message_size >> 8);
721 	dat[3] = session->pkt.total;
722 
723 	if (session->skcb.addr.type == J1939_ETP) {
724 		dat[0] = J1939_ETP_CMD_RTS;
725 		dat[1] = (session->total_message_size >> 0);
726 		dat[2] = (session->total_message_size >> 8);
727 		dat[3] = (session->total_message_size >> 16);
728 		dat[4] = (session->total_message_size >> 24);
729 	} else if (j1939_cb_is_broadcast(&session->skcb)) {
730 		dat[0] = J1939_TP_CMD_BAM;
731 		/* fake cts for broadcast */
732 		session->pkt.tx = 0;
733 	} else {
734 		dat[0] = J1939_TP_CMD_RTS;
735 		dat[4] = dat[3];
736 	}
737 
738 	if (dat[0] == session->last_txcmd)
739 		/* done already */
740 		return 0;
741 
742 	ret = j1939_tp_tx_ctl(session, false, dat);
743 	if (ret < 0)
744 		return ret;
745 
746 	session->last_txcmd = dat[0];
747 	if (dat[0] == J1939_TP_CMD_BAM) {
748 		j1939_tp_schedule_txtimer(session, 50);
749 		j1939_tp_set_rxtimeout(session, 250);
750 	} else {
751 		j1939_tp_set_rxtimeout(session, 1250);
752 	}
753 
754 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
755 
756 	return 0;
757 }
758 
759 static int j1939_session_tx_dpo(struct j1939_session *session)
760 {
761 	unsigned int pkt;
762 	u8 dat[8];
763 	int ret;
764 
765 	memset(dat, 0xff, sizeof(dat));
766 
767 	dat[0] = J1939_ETP_CMD_DPO;
768 	session->pkt.dpo = session->pkt.tx_acked;
769 	pkt = session->pkt.dpo;
770 	dat[1] = session->pkt.last - session->pkt.tx_acked;
771 	dat[2] = (pkt >> 0);
772 	dat[3] = (pkt >> 8);
773 	dat[4] = (pkt >> 16);
774 
775 	ret = j1939_tp_tx_ctl(session, false, dat);
776 	if (ret < 0)
777 		return ret;
778 
779 	session->last_txcmd = dat[0];
780 	j1939_tp_set_rxtimeout(session, 1250);
781 	session->pkt.tx = session->pkt.tx_acked;
782 
783 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
784 
785 	return 0;
786 }
787 
788 static int j1939_session_tx_dat(struct j1939_session *session)
789 {
790 	struct j1939_priv *priv = session->priv;
791 	struct j1939_sk_buff_cb *se_skcb;
792 	int offset, pkt_done, pkt_end;
793 	unsigned int len, pdelay;
794 	struct sk_buff *se_skb;
795 	const u8 *tpdat;
796 	int ret = 0;
797 	u8 dat[8];
798 
799 	se_skb = j1939_session_skb_get_by_offset(session, session->pkt.tx * 7);
800 	if (!se_skb)
801 		return -ENOBUFS;
802 
803 	se_skcb = j1939_skb_to_cb(se_skb);
804 	tpdat = se_skb->data;
805 	ret = 0;
806 	pkt_done = 0;
807 	if (session->skcb.addr.type != J1939_ETP &&
808 	    j1939_cb_is_broadcast(&session->skcb))
809 		pkt_end = session->pkt.total;
810 	else
811 		pkt_end = session->pkt.last;
812 
813 	while (session->pkt.tx < pkt_end) {
814 		dat[0] = session->pkt.tx - session->pkt.dpo + 1;
815 		offset = (session->pkt.tx * 7) - se_skcb->offset;
816 		len =  se_skb->len - offset;
817 		if (len > 7)
818 			len = 7;
819 
820 		if (offset + len > se_skb->len) {
821 			netdev_err_once(priv->ndev,
822 					"%s: 0x%p: requested data outside of queued buffer: offset %i, len %i, pkt.tx: %i\n",
823 					__func__, session, se_skcb->offset,
824 					se_skb->len , session->pkt.tx);
825 			ret = -EOVERFLOW;
826 			goto out_free;
827 		}
828 
829 		if (!len) {
830 			ret = -ENOBUFS;
831 			break;
832 		}
833 
834 		memcpy(&dat[1], &tpdat[offset], len);
835 		ret = j1939_tp_tx_dat(session, dat, len + 1);
836 		if (ret < 0) {
837 			/* ENOBUFS == CAN interface TX queue is full */
838 			if (ret != -ENOBUFS)
839 				netdev_alert(priv->ndev,
840 					     "%s: 0x%p: queue data error: %i\n",
841 					     __func__, session, ret);
842 			break;
843 		}
844 
845 		session->last_txcmd = 0xff;
846 		pkt_done++;
847 		session->pkt.tx++;
848 		pdelay = j1939_cb_is_broadcast(&session->skcb) ? 50 :
849 			j1939_tp_packet_delay;
850 
851 		if (session->pkt.tx < session->pkt.total && pdelay) {
852 			j1939_tp_schedule_txtimer(session, pdelay);
853 			break;
854 		}
855 	}
856 
857 	if (pkt_done)
858 		j1939_tp_set_rxtimeout(session, 250);
859 
860  out_free:
861 	if (ret)
862 		kfree_skb(se_skb);
863 	else
864 		consume_skb(se_skb);
865 
866 	return ret;
867 }
868 
869 static int j1939_xtp_txnext_transmiter(struct j1939_session *session)
870 {
871 	struct j1939_priv *priv = session->priv;
872 	int ret = 0;
873 
874 	if (!j1939_tp_im_transmitter(&session->skcb)) {
875 		netdev_alert(priv->ndev, "%s: 0x%p: called by not transmitter!\n",
876 			     __func__, session);
877 		return -EINVAL;
878 	}
879 
880 	switch (session->last_cmd) {
881 	case 0:
882 		ret = j1939_session_tx_rts(session);
883 		break;
884 
885 	case J1939_ETP_CMD_CTS:
886 		if (session->last_txcmd != J1939_ETP_CMD_DPO) {
887 			ret = j1939_session_tx_dpo(session);
888 			if (ret)
889 				return ret;
890 		}
891 
892 		fallthrough;
893 	case J1939_TP_CMD_CTS:
894 	case 0xff: /* did some data */
895 	case J1939_ETP_CMD_DPO:
896 	case J1939_TP_CMD_BAM:
897 		ret = j1939_session_tx_dat(session);
898 
899 		break;
900 	default:
901 		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
902 			     __func__, session, session->last_cmd);
903 	}
904 
905 	return ret;
906 }
907 
908 static int j1939_session_tx_cts(struct j1939_session *session)
909 {
910 	struct j1939_priv *priv = session->priv;
911 	unsigned int pkt, len;
912 	int ret;
913 	u8 dat[8];
914 
915 	if (!j1939_sk_recv_match(priv, &session->skcb))
916 		return -ENOENT;
917 
918 	len = session->pkt.total - session->pkt.rx;
919 	len = min3(len, session->pkt.block, j1939_tp_block ?: 255);
920 	memset(dat, 0xff, sizeof(dat));
921 
922 	if (session->skcb.addr.type == J1939_ETP) {
923 		pkt = session->pkt.rx + 1;
924 		dat[0] = J1939_ETP_CMD_CTS;
925 		dat[1] = len;
926 		dat[2] = (pkt >> 0);
927 		dat[3] = (pkt >> 8);
928 		dat[4] = (pkt >> 16);
929 	} else {
930 		dat[0] = J1939_TP_CMD_CTS;
931 		dat[1] = len;
932 		dat[2] = session->pkt.rx + 1;
933 	}
934 
935 	if (dat[0] == session->last_txcmd)
936 		/* done already */
937 		return 0;
938 
939 	ret = j1939_tp_tx_ctl(session, true, dat);
940 	if (ret < 0)
941 		return ret;
942 
943 	if (len)
944 		/* only mark cts done when len is set */
945 		session->last_txcmd = dat[0];
946 	j1939_tp_set_rxtimeout(session, 1250);
947 
948 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
949 
950 	return 0;
951 }
952 
953 static int j1939_session_tx_eoma(struct j1939_session *session)
954 {
955 	struct j1939_priv *priv = session->priv;
956 	u8 dat[8];
957 	int ret;
958 
959 	if (!j1939_sk_recv_match(priv, &session->skcb))
960 		return -ENOENT;
961 
962 	memset(dat, 0xff, sizeof(dat));
963 
964 	if (session->skcb.addr.type == J1939_ETP) {
965 		dat[0] = J1939_ETP_CMD_EOMA;
966 		dat[1] = session->total_message_size >> 0;
967 		dat[2] = session->total_message_size >> 8;
968 		dat[3] = session->total_message_size >> 16;
969 		dat[4] = session->total_message_size >> 24;
970 	} else {
971 		dat[0] = J1939_TP_CMD_EOMA;
972 		dat[1] = session->total_message_size;
973 		dat[2] = session->total_message_size >> 8;
974 		dat[3] = session->pkt.total;
975 	}
976 
977 	if (dat[0] == session->last_txcmd)
978 		/* done already */
979 		return 0;
980 
981 	ret = j1939_tp_tx_ctl(session, true, dat);
982 	if (ret < 0)
983 		return ret;
984 
985 	session->last_txcmd = dat[0];
986 
987 	/* wait for the EOMA packet to come in */
988 	j1939_tp_set_rxtimeout(session, 1250);
989 
990 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
991 
992 	return 0;
993 }
994 
995 static int j1939_xtp_txnext_receiver(struct j1939_session *session)
996 {
997 	struct j1939_priv *priv = session->priv;
998 	int ret = 0;
999 
1000 	if (!j1939_tp_im_receiver(&session->skcb)) {
1001 		netdev_alert(priv->ndev, "%s: 0x%p: called by not receiver!\n",
1002 			     __func__, session);
1003 		return -EINVAL;
1004 	}
1005 
1006 	switch (session->last_cmd) {
1007 	case J1939_TP_CMD_RTS:
1008 	case J1939_ETP_CMD_RTS:
1009 		ret = j1939_session_tx_cts(session);
1010 		break;
1011 
1012 	case J1939_ETP_CMD_CTS:
1013 	case J1939_TP_CMD_CTS:
1014 	case 0xff: /* did some data */
1015 	case J1939_ETP_CMD_DPO:
1016 		if ((session->skcb.addr.type == J1939_TP &&
1017 		     j1939_cb_is_broadcast(&session->skcb)))
1018 			break;
1019 
1020 		if (session->pkt.rx >= session->pkt.total) {
1021 			ret = j1939_session_tx_eoma(session);
1022 		} else if (session->pkt.rx >= session->pkt.last) {
1023 			session->last_txcmd = 0;
1024 			ret = j1939_session_tx_cts(session);
1025 		}
1026 		break;
1027 	default:
1028 		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
1029 			     __func__, session, session->last_cmd);
1030 	}
1031 
1032 	return ret;
1033 }
1034 
1035 static int j1939_simple_txnext(struct j1939_session *session)
1036 {
1037 	struct j1939_priv *priv = session->priv;
1038 	struct sk_buff *se_skb = j1939_session_skb_get(session);
1039 	struct sk_buff *skb;
1040 	int ret;
1041 
1042 	if (!se_skb)
1043 		return 0;
1044 
1045 	skb = skb_clone(se_skb, GFP_ATOMIC);
1046 	if (!skb) {
1047 		ret = -ENOMEM;
1048 		goto out_free;
1049 	}
1050 
1051 	can_skb_set_owner(skb, se_skb->sk);
1052 
1053 	j1939_tp_set_rxtimeout(session, J1939_SIMPLE_ECHO_TIMEOUT_MS);
1054 
1055 	ret = j1939_send_one(priv, skb);
1056 	if (ret)
1057 		goto out_free;
1058 
1059 	j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_SCHED);
1060 	j1939_sk_queue_activate_next(session);
1061 
1062  out_free:
1063 	if (ret)
1064 		kfree_skb(se_skb);
1065 	else
1066 		consume_skb(se_skb);
1067 
1068 	return ret;
1069 }
1070 
1071 static bool j1939_session_deactivate_locked(struct j1939_session *session)
1072 {
1073 	bool active = false;
1074 
1075 	lockdep_assert_held(&session->priv->active_session_list_lock);
1076 
1077 	if (session->state >= J1939_SESSION_ACTIVE &&
1078 	    session->state < J1939_SESSION_ACTIVE_MAX) {
1079 		active = true;
1080 
1081 		list_del_init(&session->active_session_list_entry);
1082 		session->state = J1939_SESSION_DONE;
1083 		j1939_session_put(session);
1084 	}
1085 
1086 	return active;
1087 }
1088 
1089 static bool j1939_session_deactivate(struct j1939_session *session)
1090 {
1091 	struct j1939_priv *priv = session->priv;
1092 	bool active;
1093 
1094 	j1939_session_list_lock(priv);
1095 	active = j1939_session_deactivate_locked(session);
1096 	j1939_session_list_unlock(priv);
1097 
1098 	return active;
1099 }
1100 
1101 static void
1102 j1939_session_deactivate_activate_next(struct j1939_session *session)
1103 {
1104 	if (j1939_session_deactivate(session))
1105 		j1939_sk_queue_activate_next(session);
1106 }
1107 
1108 static void __j1939_session_cancel(struct j1939_session *session,
1109 				   enum j1939_xtp_abort err)
1110 {
1111 	struct j1939_priv *priv = session->priv;
1112 
1113 	WARN_ON_ONCE(!err);
1114 	lockdep_assert_held(&session->priv->active_session_list_lock);
1115 
1116 	session->err = j1939_xtp_abort_to_errno(priv, err);
1117 	session->state = J1939_SESSION_WAITING_ABORT;
1118 	/* do not send aborts on incoming broadcasts */
1119 	if (!j1939_cb_is_broadcast(&session->skcb)) {
1120 		j1939_xtp_tx_abort(priv, &session->skcb,
1121 				   !session->transmission,
1122 				   err, session->skcb.addr.pgn);
1123 	}
1124 
1125 	if (session->sk)
1126 		j1939_sk_send_loop_abort(session->sk, session->err);
1127 	else
1128 		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
1129 }
1130 
1131 static void j1939_session_cancel(struct j1939_session *session,
1132 				 enum j1939_xtp_abort err)
1133 {
1134 	j1939_session_list_lock(session->priv);
1135 
1136 	if (session->state >= J1939_SESSION_ACTIVE &&
1137 	    session->state < J1939_SESSION_WAITING_ABORT) {
1138 		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
1139 		__j1939_session_cancel(session, err);
1140 	}
1141 
1142 	j1939_session_list_unlock(session->priv);
1143 }
1144 
1145 static enum hrtimer_restart j1939_tp_txtimer(struct hrtimer *hrtimer)
1146 {
1147 	struct j1939_session *session =
1148 		container_of(hrtimer, struct j1939_session, txtimer);
1149 	struct j1939_priv *priv = session->priv;
1150 	int ret = 0;
1151 
1152 	if (session->skcb.addr.type == J1939_SIMPLE) {
1153 		ret = j1939_simple_txnext(session);
1154 	} else {
1155 		if (session->transmission)
1156 			ret = j1939_xtp_txnext_transmiter(session);
1157 		else
1158 			ret = j1939_xtp_txnext_receiver(session);
1159 	}
1160 
1161 	switch (ret) {
1162 	case -ENOBUFS:
1163 		/* Retry limit is currently arbitrary chosen */
1164 		if (session->tx_retry < J1939_XTP_TX_RETRY_LIMIT) {
1165 			session->tx_retry++;
1166 			j1939_tp_schedule_txtimer(session,
1167 						  10 + get_random_u32_below(16));
1168 		} else {
1169 			netdev_alert(priv->ndev, "%s: 0x%p: tx retry count reached\n",
1170 				     __func__, session);
1171 			session->err = -ENETUNREACH;
1172 			j1939_session_rxtimer_cancel(session);
1173 			j1939_session_deactivate_activate_next(session);
1174 		}
1175 		break;
1176 	case -ENETDOWN:
1177 		/* In this case we should get a netdev_event(), all active
1178 		 * sessions will be cleared by
1179 		 * j1939_cancel_all_active_sessions(). So handle this as an
1180 		 * error, but let j1939_cancel_all_active_sessions() do the
1181 		 * cleanup including propagation of the error to user space.
1182 		 */
1183 		break;
1184 	case -EOVERFLOW:
1185 		j1939_session_cancel(session, J1939_XTP_ABORT_ECTS_TOO_BIG);
1186 		break;
1187 	case 0:
1188 		session->tx_retry = 0;
1189 		break;
1190 	default:
1191 		netdev_alert(priv->ndev, "%s: 0x%p: tx aborted with unknown reason: %i\n",
1192 			     __func__, session, ret);
1193 		if (session->skcb.addr.type != J1939_SIMPLE) {
1194 			j1939_session_cancel(session, J1939_XTP_ABORT_OTHER);
1195 		} else {
1196 			session->err = ret;
1197 			j1939_session_rxtimer_cancel(session);
1198 			j1939_session_deactivate_activate_next(session);
1199 		}
1200 	}
1201 
1202 	j1939_session_put(session);
1203 
1204 	return HRTIMER_NORESTART;
1205 }
1206 
1207 static void j1939_session_completed(struct j1939_session *session)
1208 {
1209 	struct sk_buff *se_skb;
1210 
1211 	if (!session->transmission) {
1212 		se_skb = j1939_session_skb_get(session);
1213 		/* distribute among j1939 receivers */
1214 		j1939_sk_recv(session->priv, se_skb);
1215 		consume_skb(se_skb);
1216 	}
1217 
1218 	j1939_session_deactivate_activate_next(session);
1219 }
1220 
1221 static enum hrtimer_restart j1939_tp_rxtimer(struct hrtimer *hrtimer)
1222 {
1223 	struct j1939_session *session = container_of(hrtimer,
1224 						     struct j1939_session,
1225 						     rxtimer);
1226 	struct j1939_priv *priv = session->priv;
1227 
1228 	if (session->state == J1939_SESSION_WAITING_ABORT) {
1229 		netdev_alert(priv->ndev, "%s: 0x%p: abort rx timeout. Force session deactivation\n",
1230 			     __func__, session);
1231 
1232 		j1939_session_deactivate_activate_next(session);
1233 
1234 	} else if (session->skcb.addr.type == J1939_SIMPLE) {
1235 		netdev_alert(priv->ndev, "%s: 0x%p: Timeout. Failed to send simple message.\n",
1236 			     __func__, session);
1237 
1238 		/* The message is probably stuck in the CAN controller and can
1239 		 * be send as soon as CAN bus is in working state again.
1240 		 */
1241 		session->err = -ETIME;
1242 		j1939_session_deactivate(session);
1243 	} else {
1244 		j1939_session_list_lock(session->priv);
1245 		if (session->state >= J1939_SESSION_ACTIVE &&
1246 		    session->state < J1939_SESSION_ACTIVE_MAX) {
1247 			netdev_alert(priv->ndev, "%s: 0x%p: rx timeout, send abort\n",
1248 				     __func__, session);
1249 			j1939_session_get(session);
1250 			hrtimer_start(&session->rxtimer,
1251 				      ms_to_ktime(J1939_XTP_ABORT_TIMEOUT_MS),
1252 				      HRTIMER_MODE_REL_SOFT);
1253 			__j1939_session_cancel(session, J1939_XTP_ABORT_TIMEOUT);
1254 		}
1255 		j1939_session_list_unlock(session->priv);
1256 	}
1257 
1258 	j1939_session_put(session);
1259 
1260 	return HRTIMER_NORESTART;
1261 }
1262 
1263 static bool j1939_xtp_rx_cmd_bad_pgn(struct j1939_session *session,
1264 				     const struct sk_buff *skb)
1265 {
1266 	const struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1267 	pgn_t pgn = j1939_xtp_ctl_to_pgn(skb->data);
1268 	struct j1939_priv *priv = session->priv;
1269 	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
1270 	u8 cmd = skb->data[0];
1271 
1272 	if (session->skcb.addr.pgn == pgn)
1273 		return false;
1274 
1275 	switch (cmd) {
1276 	case J1939_TP_CMD_BAM:
1277 		abort = J1939_XTP_NO_ABORT;
1278 		break;
1279 
1280 	case J1939_ETP_CMD_RTS:
1281 		fallthrough;
1282 	case J1939_TP_CMD_RTS:
1283 		abort = J1939_XTP_ABORT_BUSY;
1284 		break;
1285 
1286 	case J1939_ETP_CMD_CTS:
1287 		fallthrough;
1288 	case J1939_TP_CMD_CTS:
1289 		abort = J1939_XTP_ABORT_ECTS_UNXPECTED_PGN;
1290 		break;
1291 
1292 	case J1939_ETP_CMD_DPO:
1293 		abort = J1939_XTP_ABORT_BAD_EDPO_PGN;
1294 		break;
1295 
1296 	case J1939_ETP_CMD_EOMA:
1297 		fallthrough;
1298 	case J1939_TP_CMD_EOMA:
1299 		abort = J1939_XTP_ABORT_OTHER;
1300 		break;
1301 
1302 	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
1303 		abort = J1939_XTP_NO_ABORT;
1304 		break;
1305 
1306 	default:
1307 		WARN_ON_ONCE(1);
1308 		break;
1309 	}
1310 
1311 	netdev_warn(priv->ndev, "%s: 0x%p: CMD 0x%02x with PGN 0x%05x for running session with different PGN 0x%05x.\n",
1312 		    __func__, session, cmd, pgn, session->skcb.addr.pgn);
1313 	if (abort != J1939_XTP_NO_ABORT)
1314 		j1939_xtp_tx_abort(priv, skcb, true, abort, pgn);
1315 
1316 	return true;
1317 }
1318 
1319 static void j1939_xtp_rx_abort_one(struct j1939_priv *priv, struct sk_buff *skb,
1320 				   bool reverse, bool transmitter)
1321 {
1322 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1323 	struct j1939_session *session;
1324 	u8 abort = skb->data[1];
1325 
1326 	session = j1939_session_get_by_addr(priv, &skcb->addr, reverse,
1327 					    transmitter);
1328 	if (!session)
1329 		return;
1330 
1331 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1332 		goto abort_put;
1333 
1334 	netdev_info(priv->ndev, "%s: 0x%p: 0x%05x: (%u) %s\n", __func__,
1335 		    session, j1939_xtp_ctl_to_pgn(skb->data), abort,
1336 		    j1939_xtp_abort_to_str(abort));
1337 
1338 	j1939_session_timers_cancel(session);
1339 	session->err = j1939_xtp_abort_to_errno(priv, abort);
1340 	if (session->sk)
1341 		j1939_sk_send_loop_abort(session->sk, session->err);
1342 	else
1343 		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
1344 	j1939_session_deactivate_activate_next(session);
1345 
1346 abort_put:
1347 	j1939_session_put(session);
1348 }
1349 
1350 /* abort packets may come in 2 directions */
1351 static void
1352 j1939_xtp_rx_abort(struct j1939_priv *priv, struct sk_buff *skb,
1353 		   bool transmitter)
1354 {
1355 	j1939_xtp_rx_abort_one(priv, skb, false, transmitter);
1356 	j1939_xtp_rx_abort_one(priv, skb, true, transmitter);
1357 }
1358 
1359 static void
1360 j1939_xtp_rx_eoma_one(struct j1939_session *session, struct sk_buff *skb)
1361 {
1362 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1363 	const u8 *dat;
1364 	int len;
1365 
1366 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1367 		return;
1368 
1369 	dat = skb->data;
1370 
1371 	if (skcb->addr.type == J1939_ETP)
1372 		len = j1939_etp_ctl_to_size(dat);
1373 	else
1374 		len = j1939_tp_ctl_to_size(dat);
1375 
1376 	if (session->total_message_size != len) {
1377 		netdev_warn_once(session->priv->ndev,
1378 				 "%s: 0x%p: Incorrect size. Expected: %i; got: %i.\n",
1379 				 __func__, session, session->total_message_size,
1380 				 len);
1381 	}
1382 
1383 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1384 
1385 	session->pkt.tx_acked = session->pkt.total;
1386 	j1939_session_timers_cancel(session);
1387 	/* transmitted without problems */
1388 	j1939_session_completed(session);
1389 }
1390 
1391 static void
1392 j1939_xtp_rx_eoma(struct j1939_priv *priv, struct sk_buff *skb,
1393 		  bool transmitter)
1394 {
1395 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1396 	struct j1939_session *session;
1397 
1398 	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
1399 					    transmitter);
1400 	if (!session)
1401 		return;
1402 
1403 	j1939_xtp_rx_eoma_one(session, skb);
1404 	j1939_session_put(session);
1405 }
1406 
1407 static void
1408 j1939_xtp_rx_cts_one(struct j1939_session *session, struct sk_buff *skb)
1409 {
1410 	enum j1939_xtp_abort err = J1939_XTP_ABORT_FAULT;
1411 	unsigned int pkt;
1412 	const u8 *dat;
1413 
1414 	dat = skb->data;
1415 
1416 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1417 		return;
1418 
1419 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1420 
1421 	if (session->last_cmd == dat[0]) {
1422 		err = J1939_XTP_ABORT_DUP_SEQ;
1423 		goto out_session_cancel;
1424 	}
1425 
1426 	if (session->skcb.addr.type == J1939_ETP)
1427 		pkt = j1939_etp_ctl_to_packet(dat);
1428 	else
1429 		pkt = dat[2];
1430 
1431 	if (!pkt)
1432 		goto out_session_cancel;
1433 	else if (dat[1] > session->pkt.block /* 0xff for etp */)
1434 		goto out_session_cancel;
1435 
1436 	/* set packet counters only when not CTS(0) */
1437 	session->pkt.tx_acked = pkt - 1;
1438 	j1939_session_skb_drop_old(session);
1439 	session->pkt.last = session->pkt.tx_acked + dat[1];
1440 	if (session->pkt.last > session->pkt.total)
1441 		/* safety measure */
1442 		session->pkt.last = session->pkt.total;
1443 	/* TODO: do not set tx here, do it in txtimer */
1444 	session->pkt.tx = session->pkt.tx_acked;
1445 
1446 	session->last_cmd = dat[0];
1447 	if (dat[1]) {
1448 		j1939_tp_set_rxtimeout(session, 1250);
1449 		if (session->transmission) {
1450 			if (session->pkt.tx_acked)
1451 				j1939_sk_errqueue(session,
1452 						  J1939_ERRQUEUE_TX_SCHED);
1453 			j1939_session_txtimer_cancel(session);
1454 			j1939_tp_schedule_txtimer(session, 0);
1455 		}
1456 	} else {
1457 		/* CTS(0) */
1458 		j1939_tp_set_rxtimeout(session, 550);
1459 	}
1460 	return;
1461 
1462  out_session_cancel:
1463 	j1939_session_timers_cancel(session);
1464 	j1939_session_cancel(session, err);
1465 }
1466 
1467 static void
1468 j1939_xtp_rx_cts(struct j1939_priv *priv, struct sk_buff *skb, bool transmitter)
1469 {
1470 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1471 	struct j1939_session *session;
1472 
1473 	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
1474 					    transmitter);
1475 	if (!session)
1476 		return;
1477 	j1939_xtp_rx_cts_one(session, skb);
1478 	j1939_session_put(session);
1479 }
1480 
1481 static struct j1939_session *j1939_session_new(struct j1939_priv *priv,
1482 					       struct sk_buff *skb, size_t size)
1483 {
1484 	struct j1939_session *session;
1485 	struct j1939_sk_buff_cb *skcb;
1486 
1487 	session = kzalloc(sizeof(*session), gfp_any());
1488 	if (!session)
1489 		return NULL;
1490 
1491 	INIT_LIST_HEAD(&session->active_session_list_entry);
1492 	INIT_LIST_HEAD(&session->sk_session_queue_entry);
1493 	kref_init(&session->kref);
1494 
1495 	j1939_priv_get(priv);
1496 	session->priv = priv;
1497 	session->total_message_size = size;
1498 	session->state = J1939_SESSION_NEW;
1499 
1500 	skb_queue_head_init(&session->skb_queue);
1501 	skb_queue_tail(&session->skb_queue, skb);
1502 
1503 	skcb = j1939_skb_to_cb(skb);
1504 	memcpy(&session->skcb, skcb, sizeof(session->skcb));
1505 
1506 	hrtimer_init(&session->txtimer, CLOCK_MONOTONIC,
1507 		     HRTIMER_MODE_REL_SOFT);
1508 	session->txtimer.function = j1939_tp_txtimer;
1509 	hrtimer_init(&session->rxtimer, CLOCK_MONOTONIC,
1510 		     HRTIMER_MODE_REL_SOFT);
1511 	session->rxtimer.function = j1939_tp_rxtimer;
1512 
1513 	netdev_dbg(priv->ndev, "%s: 0x%p: sa: %02x, da: %02x\n",
1514 		   __func__, session, skcb->addr.sa, skcb->addr.da);
1515 
1516 	return session;
1517 }
1518 
1519 static struct
1520 j1939_session *j1939_session_fresh_new(struct j1939_priv *priv,
1521 				       int size,
1522 				       const struct j1939_sk_buff_cb *rel_skcb)
1523 {
1524 	struct sk_buff *skb;
1525 	struct j1939_sk_buff_cb *skcb;
1526 	struct j1939_session *session;
1527 
1528 	skb = alloc_skb(size + sizeof(struct can_skb_priv), GFP_ATOMIC);
1529 	if (unlikely(!skb))
1530 		return NULL;
1531 
1532 	skb->dev = priv->ndev;
1533 	can_skb_reserve(skb);
1534 	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
1535 	can_skb_prv(skb)->skbcnt = 0;
1536 	skcb = j1939_skb_to_cb(skb);
1537 	memcpy(skcb, rel_skcb, sizeof(*skcb));
1538 
1539 	session = j1939_session_new(priv, skb, size);
1540 	if (!session) {
1541 		kfree_skb(skb);
1542 		return NULL;
1543 	}
1544 
1545 	/* alloc data area */
1546 	skb_put(skb, size);
1547 	/* skb is recounted in j1939_session_new() */
1548 	return session;
1549 }
1550 
1551 int j1939_session_activate(struct j1939_session *session)
1552 {
1553 	struct j1939_priv *priv = session->priv;
1554 	struct j1939_session *active = NULL;
1555 	int ret = 0;
1556 
1557 	j1939_session_list_lock(priv);
1558 	if (session->skcb.addr.type != J1939_SIMPLE)
1559 		active = j1939_session_get_by_addr_locked(priv,
1560 							  &priv->active_session_list,
1561 							  &session->skcb.addr, false,
1562 							  session->transmission);
1563 	if (active) {
1564 		j1939_session_put(active);
1565 		ret = -EAGAIN;
1566 	} else {
1567 		WARN_ON_ONCE(session->state != J1939_SESSION_NEW);
1568 		list_add_tail(&session->active_session_list_entry,
1569 			      &priv->active_session_list);
1570 		j1939_session_get(session);
1571 		session->state = J1939_SESSION_ACTIVE;
1572 
1573 		netdev_dbg(session->priv->ndev, "%s: 0x%p\n",
1574 			   __func__, session);
1575 	}
1576 	j1939_session_list_unlock(priv);
1577 
1578 	return ret;
1579 }
1580 
1581 static struct
1582 j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv,
1583 					    struct sk_buff *skb)
1584 {
1585 	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
1586 	struct j1939_sk_buff_cb skcb = *j1939_skb_to_cb(skb);
1587 	struct j1939_session *session;
1588 	const u8 *dat;
1589 	pgn_t pgn;
1590 	int len;
1591 
1592 	netdev_dbg(priv->ndev, "%s\n", __func__);
1593 
1594 	dat = skb->data;
1595 	pgn = j1939_xtp_ctl_to_pgn(dat);
1596 	skcb.addr.pgn = pgn;
1597 
1598 	if (!j1939_sk_recv_match(priv, &skcb))
1599 		return NULL;
1600 
1601 	if (skcb.addr.type == J1939_ETP) {
1602 		len = j1939_etp_ctl_to_size(dat);
1603 		if (len > J1939_MAX_ETP_PACKET_SIZE)
1604 			abort = J1939_XTP_ABORT_FAULT;
1605 		else if (len > priv->tp_max_packet_size)
1606 			abort = J1939_XTP_ABORT_RESOURCE;
1607 		else if (len <= J1939_MAX_TP_PACKET_SIZE)
1608 			abort = J1939_XTP_ABORT_FAULT;
1609 	} else {
1610 		len = j1939_tp_ctl_to_size(dat);
1611 		if (len > J1939_MAX_TP_PACKET_SIZE)
1612 			abort = J1939_XTP_ABORT_FAULT;
1613 		else if (len > priv->tp_max_packet_size)
1614 			abort = J1939_XTP_ABORT_RESOURCE;
1615 		else if (len < J1939_MIN_TP_PACKET_SIZE)
1616 			abort = J1939_XTP_ABORT_FAULT;
1617 	}
1618 
1619 	if (abort != J1939_XTP_NO_ABORT) {
1620 		j1939_xtp_tx_abort(priv, &skcb, true, abort, pgn);
1621 		return NULL;
1622 	}
1623 
1624 	session = j1939_session_fresh_new(priv, len, &skcb);
1625 	if (!session) {
1626 		j1939_xtp_tx_abort(priv, &skcb, true,
1627 				   J1939_XTP_ABORT_RESOURCE, pgn);
1628 		return NULL;
1629 	}
1630 
1631 	/* initialize the control buffer: plain copy */
1632 	session->pkt.total = (len + 6) / 7;
1633 	session->pkt.block = 0xff;
1634 	if (skcb.addr.type != J1939_ETP) {
1635 		if (dat[3] != session->pkt.total)
1636 			netdev_alert(priv->ndev, "%s: 0x%p: strange total, %u != %u\n",
1637 				     __func__, session, session->pkt.total,
1638 				     dat[3]);
1639 		session->pkt.total = dat[3];
1640 		session->pkt.block = min(dat[3], dat[4]);
1641 	}
1642 
1643 	session->pkt.rx = 0;
1644 	session->pkt.tx = 0;
1645 
1646 	session->tskey = priv->rx_tskey++;
1647 	j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_RTS);
1648 
1649 	WARN_ON_ONCE(j1939_session_activate(session));
1650 
1651 	return session;
1652 }
1653 
1654 static int j1939_xtp_rx_rts_session_active(struct j1939_session *session,
1655 					   struct sk_buff *skb)
1656 {
1657 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1658 	struct j1939_priv *priv = session->priv;
1659 
1660 	if (!session->transmission) {
1661 		if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1662 			return -EBUSY;
1663 
1664 		/* RTS on active session */
1665 		j1939_session_timers_cancel(session);
1666 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
1667 	}
1668 
1669 	if (session->last_cmd != 0) {
1670 		/* we received a second rts on the same connection */
1671 		netdev_alert(priv->ndev, "%s: 0x%p: connection exists (%02x %02x). last cmd: %x\n",
1672 			     __func__, session, skcb->addr.sa, skcb->addr.da,
1673 			     session->last_cmd);
1674 
1675 		j1939_session_timers_cancel(session);
1676 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
1677 
1678 		return -EBUSY;
1679 	}
1680 
1681 	if (session->skcb.addr.sa != skcb->addr.sa ||
1682 	    session->skcb.addr.da != skcb->addr.da)
1683 		netdev_warn(priv->ndev, "%s: 0x%p: session->skcb.addr.sa=0x%02x skcb->addr.sa=0x%02x session->skcb.addr.da=0x%02x skcb->addr.da=0x%02x\n",
1684 			    __func__, session,
1685 			    session->skcb.addr.sa, skcb->addr.sa,
1686 			    session->skcb.addr.da, skcb->addr.da);
1687 	/* make sure 'sa' & 'da' are correct !
1688 	 * They may be 'not filled in yet' for sending
1689 	 * skb's, since they did not pass the Address Claim ever.
1690 	 */
1691 	session->skcb.addr.sa = skcb->addr.sa;
1692 	session->skcb.addr.da = skcb->addr.da;
1693 
1694 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1695 
1696 	return 0;
1697 }
1698 
1699 static void j1939_xtp_rx_rts(struct j1939_priv *priv, struct sk_buff *skb,
1700 			     bool transmitter)
1701 {
1702 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1703 	struct j1939_session *session;
1704 	u8 cmd = skb->data[0];
1705 
1706 	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1707 					    transmitter);
1708 
1709 	if (!session) {
1710 		if (transmitter) {
1711 			/* If we're the transmitter and this function is called,
1712 			 * we received our own RTS. A session has already been
1713 			 * created.
1714 			 *
1715 			 * For some reasons however it might have been destroyed
1716 			 * already. So don't create a new one here (using
1717 			 * "j1939_xtp_rx_rts_session_new()") as this will be a
1718 			 * receiver session.
1719 			 *
1720 			 * The reasons the session is already destroyed might
1721 			 * be:
1722 			 * - user space closed socket was and the session was
1723 			 *   aborted
1724 			 * - session was aborted due to external abort message
1725 			 */
1726 			return;
1727 		}
1728 		session = j1939_xtp_rx_rts_session_new(priv, skb);
1729 		if (!session) {
1730 			if (cmd == J1939_TP_CMD_BAM && j1939_sk_recv_match(priv, skcb))
1731 				netdev_info(priv->ndev, "%s: failed to create TP BAM session\n",
1732 					    __func__);
1733 			return;
1734 		}
1735 	} else {
1736 		if (j1939_xtp_rx_rts_session_active(session, skb)) {
1737 			j1939_session_put(session);
1738 			return;
1739 		}
1740 	}
1741 	session->last_cmd = cmd;
1742 
1743 	if (cmd == J1939_TP_CMD_BAM) {
1744 		if (!session->transmission)
1745 			j1939_tp_set_rxtimeout(session, 750);
1746 	} else {
1747 		if (!session->transmission) {
1748 			j1939_session_txtimer_cancel(session);
1749 			j1939_tp_schedule_txtimer(session, 0);
1750 		}
1751 		j1939_tp_set_rxtimeout(session, 1250);
1752 	}
1753 
1754 	j1939_session_put(session);
1755 }
1756 
1757 static void j1939_xtp_rx_dpo_one(struct j1939_session *session,
1758 				 struct sk_buff *skb)
1759 {
1760 	const u8 *dat = skb->data;
1761 
1762 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1763 		return;
1764 
1765 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1766 
1767 	/* transmitted without problems */
1768 	session->pkt.dpo = j1939_etp_ctl_to_packet(skb->data);
1769 	session->last_cmd = dat[0];
1770 	j1939_tp_set_rxtimeout(session, 750);
1771 
1772 	if (!session->transmission)
1773 		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_DPO);
1774 }
1775 
1776 static void j1939_xtp_rx_dpo(struct j1939_priv *priv, struct sk_buff *skb,
1777 			     bool transmitter)
1778 {
1779 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1780 	struct j1939_session *session;
1781 
1782 	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1783 					    transmitter);
1784 	if (!session) {
1785 		netdev_info(priv->ndev,
1786 			    "%s: no connection found\n", __func__);
1787 		return;
1788 	}
1789 
1790 	j1939_xtp_rx_dpo_one(session, skb);
1791 	j1939_session_put(session);
1792 }
1793 
1794 static void j1939_xtp_rx_dat_one(struct j1939_session *session,
1795 				 struct sk_buff *skb)
1796 {
1797 	enum j1939_xtp_abort abort = J1939_XTP_ABORT_FAULT;
1798 	struct j1939_priv *priv = session->priv;
1799 	struct j1939_sk_buff_cb *skcb, *se_skcb;
1800 	struct sk_buff *se_skb = NULL;
1801 	const u8 *dat;
1802 	u8 *tpdat;
1803 	int offset;
1804 	int nbytes;
1805 	bool final = false;
1806 	bool remain = false;
1807 	bool do_cts_eoma = false;
1808 	int packet;
1809 
1810 	skcb = j1939_skb_to_cb(skb);
1811 	dat = skb->data;
1812 	if (skb->len != 8) {
1813 		/* makes no sense */
1814 		abort = J1939_XTP_ABORT_UNEXPECTED_DATA;
1815 		goto out_session_cancel;
1816 	}
1817 
1818 	switch (session->last_cmd) {
1819 	case 0xff:
1820 		break;
1821 	case J1939_ETP_CMD_DPO:
1822 		if (skcb->addr.type == J1939_ETP)
1823 			break;
1824 		fallthrough;
1825 	case J1939_TP_CMD_BAM:
1826 		fallthrough;
1827 	case J1939_TP_CMD_CTS:
1828 		if (skcb->addr.type != J1939_ETP)
1829 			break;
1830 		fallthrough;
1831 	default:
1832 		netdev_info(priv->ndev, "%s: 0x%p: last %02x\n", __func__,
1833 			    session, session->last_cmd);
1834 		goto out_session_cancel;
1835 	}
1836 
1837 	packet = (dat[0] - 1 + session->pkt.dpo);
1838 	if (packet > session->pkt.total ||
1839 	    (session->pkt.rx + 1) > session->pkt.total) {
1840 		netdev_info(priv->ndev, "%s: 0x%p: should have been completed\n",
1841 			    __func__, session);
1842 		goto out_session_cancel;
1843 	}
1844 
1845 	se_skb = j1939_session_skb_get_by_offset(session, packet * 7);
1846 	if (!se_skb) {
1847 		netdev_warn(priv->ndev, "%s: 0x%p: no skb found\n", __func__,
1848 			    session);
1849 		goto out_session_cancel;
1850 	}
1851 
1852 	se_skcb = j1939_skb_to_cb(se_skb);
1853 	offset = packet * 7 - se_skcb->offset;
1854 	nbytes = se_skb->len - offset;
1855 	if (nbytes > 7)
1856 		nbytes = 7;
1857 	if (nbytes <= 0 || (nbytes + 1) > skb->len) {
1858 		netdev_info(priv->ndev, "%s: 0x%p: nbytes %i, len %i\n",
1859 			    __func__, session, nbytes, skb->len);
1860 		goto out_session_cancel;
1861 	}
1862 
1863 	tpdat = se_skb->data;
1864 	if (!session->transmission) {
1865 		memcpy(&tpdat[offset], &dat[1], nbytes);
1866 	} else {
1867 		int err;
1868 
1869 		err = memcmp(&tpdat[offset], &dat[1], nbytes);
1870 		if (err)
1871 			netdev_err_once(priv->ndev,
1872 					"%s: 0x%p: Data of RX-looped back packet (%*ph) doesn't match TX data (%*ph)!\n",
1873 					__func__, session,
1874 					nbytes, &dat[1],
1875 					nbytes, &tpdat[offset]);
1876 	}
1877 
1878 	if (packet == session->pkt.rx)
1879 		session->pkt.rx++;
1880 
1881 	if (se_skcb->addr.type != J1939_ETP &&
1882 	    j1939_cb_is_broadcast(&session->skcb)) {
1883 		if (session->pkt.rx >= session->pkt.total)
1884 			final = true;
1885 		else
1886 			remain = true;
1887 	} else {
1888 		/* never final, an EOMA must follow */
1889 		if (session->pkt.rx >= session->pkt.last)
1890 			do_cts_eoma = true;
1891 	}
1892 
1893 	if (final) {
1894 		j1939_session_timers_cancel(session);
1895 		j1939_session_completed(session);
1896 	} else if (remain) {
1897 		if (!session->transmission)
1898 			j1939_tp_set_rxtimeout(session, 750);
1899 	} else if (do_cts_eoma) {
1900 		j1939_tp_set_rxtimeout(session, 1250);
1901 		if (!session->transmission)
1902 			j1939_tp_schedule_txtimer(session, 0);
1903 	} else {
1904 		j1939_tp_set_rxtimeout(session, 750);
1905 	}
1906 	session->last_cmd = 0xff;
1907 	consume_skb(se_skb);
1908 	j1939_session_put(session);
1909 
1910 	return;
1911 
1912  out_session_cancel:
1913 	kfree_skb(se_skb);
1914 	j1939_session_timers_cancel(session);
1915 	j1939_session_cancel(session, abort);
1916 	j1939_session_put(session);
1917 }
1918 
1919 static void j1939_xtp_rx_dat(struct j1939_priv *priv, struct sk_buff *skb)
1920 {
1921 	struct j1939_sk_buff_cb *skcb;
1922 	struct j1939_session *session;
1923 
1924 	skcb = j1939_skb_to_cb(skb);
1925 
1926 	if (j1939_tp_im_transmitter(skcb)) {
1927 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1928 						    true);
1929 		if (!session)
1930 			netdev_info(priv->ndev, "%s: no tx connection found\n",
1931 				    __func__);
1932 		else
1933 			j1939_xtp_rx_dat_one(session, skb);
1934 	}
1935 
1936 	if (j1939_tp_im_receiver(skcb)) {
1937 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1938 						    false);
1939 		if (!session)
1940 			netdev_info(priv->ndev, "%s: no rx connection found\n",
1941 				    __func__);
1942 		else
1943 			j1939_xtp_rx_dat_one(session, skb);
1944 	}
1945 
1946 	if (j1939_cb_is_broadcast(skcb)) {
1947 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1948 						    false);
1949 		if (session)
1950 			j1939_xtp_rx_dat_one(session, skb);
1951 	}
1952 }
1953 
1954 /* j1939 main intf */
1955 struct j1939_session *j1939_tp_send(struct j1939_priv *priv,
1956 				    struct sk_buff *skb, size_t size)
1957 {
1958 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1959 	struct j1939_session *session;
1960 	int ret;
1961 
1962 	if (skcb->addr.pgn == J1939_TP_PGN_DAT ||
1963 	    skcb->addr.pgn == J1939_TP_PGN_CTL ||
1964 	    skcb->addr.pgn == J1939_ETP_PGN_DAT ||
1965 	    skcb->addr.pgn == J1939_ETP_PGN_CTL)
1966 		/* avoid conflict */
1967 		return ERR_PTR(-EDOM);
1968 
1969 	if (size > priv->tp_max_packet_size)
1970 		return ERR_PTR(-EMSGSIZE);
1971 
1972 	if (size <= 8)
1973 		skcb->addr.type = J1939_SIMPLE;
1974 	else if (size > J1939_MAX_TP_PACKET_SIZE)
1975 		skcb->addr.type = J1939_ETP;
1976 	else
1977 		skcb->addr.type = J1939_TP;
1978 
1979 	if (skcb->addr.type == J1939_ETP &&
1980 	    j1939_cb_is_broadcast(skcb))
1981 		return ERR_PTR(-EDESTADDRREQ);
1982 
1983 	/* fill in addresses from names */
1984 	ret = j1939_ac_fixup(priv, skb);
1985 	if (unlikely(ret))
1986 		return ERR_PTR(ret);
1987 
1988 	/* fix DST flags, it may be used there soon */
1989 	if (j1939_address_is_unicast(skcb->addr.da) &&
1990 	    priv->ents[skcb->addr.da].nusers)
1991 		skcb->flags |= J1939_ECU_LOCAL_DST;
1992 
1993 	/* src is always local, I'm sending ... */
1994 	skcb->flags |= J1939_ECU_LOCAL_SRC;
1995 
1996 	/* prepare new session */
1997 	session = j1939_session_new(priv, skb, size);
1998 	if (!session)
1999 		return ERR_PTR(-ENOMEM);
2000 
2001 	/* skb is recounted in j1939_session_new() */
2002 	sock_hold(skb->sk);
2003 	session->sk = skb->sk;
2004 	session->transmission = true;
2005 	session->pkt.total = (size + 6) / 7;
2006 	session->pkt.block = skcb->addr.type == J1939_ETP ? 255 :
2007 		min(j1939_tp_block ?: 255, session->pkt.total);
2008 
2009 	if (j1939_cb_is_broadcast(&session->skcb))
2010 		/* set the end-packet for broadcast */
2011 		session->pkt.last = session->pkt.total;
2012 
2013 	skcb->tskey = atomic_inc_return(&session->sk->sk_tskey) - 1;
2014 	session->tskey = skcb->tskey;
2015 
2016 	return session;
2017 }
2018 
2019 static void j1939_tp_cmd_recv(struct j1939_priv *priv, struct sk_buff *skb)
2020 {
2021 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
2022 	int extd = J1939_TP;
2023 	u8 cmd = skb->data[0];
2024 
2025 	switch (cmd) {
2026 	case J1939_ETP_CMD_RTS:
2027 		extd = J1939_ETP;
2028 		fallthrough;
2029 	case J1939_TP_CMD_BAM:
2030 		if (cmd == J1939_TP_CMD_BAM && !j1939_cb_is_broadcast(skcb)) {
2031 			netdev_err_once(priv->ndev, "%s: BAM to unicast (%02x), ignoring!\n",
2032 					__func__, skcb->addr.sa);
2033 			return;
2034 		}
2035 		fallthrough;
2036 	case J1939_TP_CMD_RTS:
2037 		if (skcb->addr.type != extd)
2038 			return;
2039 
2040 		if (cmd == J1939_TP_CMD_RTS && j1939_cb_is_broadcast(skcb)) {
2041 			netdev_alert(priv->ndev, "%s: rts without destination (%02x)\n",
2042 				     __func__, skcb->addr.sa);
2043 			return;
2044 		}
2045 
2046 		if (j1939_tp_im_transmitter(skcb))
2047 			j1939_xtp_rx_rts(priv, skb, true);
2048 
2049 		if (j1939_tp_im_receiver(skcb) || j1939_cb_is_broadcast(skcb))
2050 			j1939_xtp_rx_rts(priv, skb, false);
2051 
2052 		break;
2053 
2054 	case J1939_ETP_CMD_CTS:
2055 		extd = J1939_ETP;
2056 		fallthrough;
2057 	case J1939_TP_CMD_CTS:
2058 		if (skcb->addr.type != extd)
2059 			return;
2060 
2061 		if (j1939_tp_im_transmitter(skcb))
2062 			j1939_xtp_rx_cts(priv, skb, false);
2063 
2064 		if (j1939_tp_im_receiver(skcb))
2065 			j1939_xtp_rx_cts(priv, skb, true);
2066 
2067 		break;
2068 
2069 	case J1939_ETP_CMD_DPO:
2070 		if (skcb->addr.type != J1939_ETP)
2071 			return;
2072 
2073 		if (j1939_tp_im_transmitter(skcb))
2074 			j1939_xtp_rx_dpo(priv, skb, true);
2075 
2076 		if (j1939_tp_im_receiver(skcb))
2077 			j1939_xtp_rx_dpo(priv, skb, false);
2078 
2079 		break;
2080 
2081 	case J1939_ETP_CMD_EOMA:
2082 		extd = J1939_ETP;
2083 		fallthrough;
2084 	case J1939_TP_CMD_EOMA:
2085 		if (skcb->addr.type != extd)
2086 			return;
2087 
2088 		if (j1939_tp_im_transmitter(skcb))
2089 			j1939_xtp_rx_eoma(priv, skb, false);
2090 
2091 		if (j1939_tp_im_receiver(skcb))
2092 			j1939_xtp_rx_eoma(priv, skb, true);
2093 
2094 		break;
2095 
2096 	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
2097 		if (j1939_cb_is_broadcast(skcb)) {
2098 			netdev_err_once(priv->ndev, "%s: abort to broadcast (%02x), ignoring!\n",
2099 					__func__, skcb->addr.sa);
2100 			return;
2101 		}
2102 
2103 		if (j1939_tp_im_transmitter(skcb))
2104 			j1939_xtp_rx_abort(priv, skb, true);
2105 
2106 		if (j1939_tp_im_receiver(skcb))
2107 			j1939_xtp_rx_abort(priv, skb, false);
2108 
2109 		break;
2110 	default:
2111 		return;
2112 	}
2113 }
2114 
2115 int j1939_tp_recv(struct j1939_priv *priv, struct sk_buff *skb)
2116 {
2117 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
2118 
2119 	if (!j1939_tp_im_involved_anydir(skcb) && !j1939_cb_is_broadcast(skcb))
2120 		return 0;
2121 
2122 	switch (skcb->addr.pgn) {
2123 	case J1939_ETP_PGN_DAT:
2124 		skcb->addr.type = J1939_ETP;
2125 		fallthrough;
2126 	case J1939_TP_PGN_DAT:
2127 		j1939_xtp_rx_dat(priv, skb);
2128 		break;
2129 
2130 	case J1939_ETP_PGN_CTL:
2131 		skcb->addr.type = J1939_ETP;
2132 		fallthrough;
2133 	case J1939_TP_PGN_CTL:
2134 		if (skb->len < 8)
2135 			return 0; /* Don't care. Nothing to extract here */
2136 
2137 		j1939_tp_cmd_recv(priv, skb);
2138 		break;
2139 	default:
2140 		return 0; /* no problem */
2141 	}
2142 	return 1; /* "I processed the message" */
2143 }
2144 
2145 void j1939_simple_recv(struct j1939_priv *priv, struct sk_buff *skb)
2146 {
2147 	struct j1939_session *session;
2148 
2149 	if (!skb->sk)
2150 		return;
2151 
2152 	if (skb->sk->sk_family != AF_CAN ||
2153 	    skb->sk->sk_protocol != CAN_J1939)
2154 		return;
2155 
2156 	j1939_session_list_lock(priv);
2157 	session = j1939_session_get_simple(priv, skb);
2158 	j1939_session_list_unlock(priv);
2159 	if (!session) {
2160 		netdev_warn(priv->ndev,
2161 			    "%s: Received already invalidated message\n",
2162 			    __func__);
2163 		return;
2164 	}
2165 
2166 	j1939_session_timers_cancel(session);
2167 	j1939_session_deactivate(session);
2168 	j1939_session_put(session);
2169 }
2170 
2171 int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk)
2172 {
2173 	struct j1939_session *session, *saved;
2174 
2175 	netdev_dbg(priv->ndev, "%s, sk: %p\n", __func__, sk);
2176 	j1939_session_list_lock(priv);
2177 	list_for_each_entry_safe(session, saved,
2178 				 &priv->active_session_list,
2179 				 active_session_list_entry) {
2180 		if (!sk || sk == session->sk) {
2181 			if (hrtimer_try_to_cancel(&session->txtimer) == 1)
2182 				j1939_session_put(session);
2183 			if (hrtimer_try_to_cancel(&session->rxtimer) == 1)
2184 				j1939_session_put(session);
2185 
2186 			session->err = ESHUTDOWN;
2187 			j1939_session_deactivate_locked(session);
2188 		}
2189 	}
2190 	j1939_session_list_unlock(priv);
2191 	return NOTIFY_DONE;
2192 }
2193 
2194 void j1939_tp_init(struct j1939_priv *priv)
2195 {
2196 	spin_lock_init(&priv->active_session_list_lock);
2197 	INIT_LIST_HEAD(&priv->active_session_list);
2198 	priv->tp_max_packet_size = J1939_MAX_ETP_PACKET_SIZE;
2199 }
2200