xref: /linux/net/can/j1939/transport.c (revision 8137a49e1567726eb10fcf55ad141ac19804ca6b)
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 	if (session->err)
264 		j1939_sk_errqueue(session, J1939_ERRQUEUE_ABORT);
265 	else
266 		j1939_sk_errqueue(session, J1939_ERRQUEUE_ACK);
267 
268 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
269 
270 	WARN_ON_ONCE(!list_empty(&session->sk_session_queue_entry));
271 	WARN_ON_ONCE(!list_empty(&session->active_session_list_entry));
272 
273 	skb_queue_purge(&session->skb_queue);
274 	__j1939_session_drop(session);
275 	j1939_priv_put(session->priv);
276 	kfree(session);
277 }
278 
279 static void __j1939_session_release(struct kref *kref)
280 {
281 	struct j1939_session *session = container_of(kref, struct j1939_session,
282 						     kref);
283 
284 	j1939_session_destroy(session);
285 }
286 
287 void j1939_session_put(struct j1939_session *session)
288 {
289 	kref_put(&session->kref, __j1939_session_release);
290 }
291 
292 static void j1939_session_txtimer_cancel(struct j1939_session *session)
293 {
294 	if (hrtimer_cancel(&session->txtimer))
295 		j1939_session_put(session);
296 }
297 
298 static void j1939_session_rxtimer_cancel(struct j1939_session *session)
299 {
300 	if (hrtimer_cancel(&session->rxtimer))
301 		j1939_session_put(session);
302 }
303 
304 void j1939_session_timers_cancel(struct j1939_session *session)
305 {
306 	j1939_session_txtimer_cancel(session);
307 	j1939_session_rxtimer_cancel(session);
308 }
309 
310 static inline bool j1939_cb_is_broadcast(const struct j1939_sk_buff_cb *skcb)
311 {
312 	return (!skcb->addr.dst_name && (skcb->addr.da == 0xff));
313 }
314 
315 static void j1939_session_skb_drop_old(struct j1939_session *session)
316 {
317 	struct sk_buff *do_skb;
318 	struct j1939_sk_buff_cb *do_skcb;
319 	unsigned int offset_start;
320 	unsigned long flags;
321 
322 	if (skb_queue_len(&session->skb_queue) < 2)
323 		return;
324 
325 	offset_start = session->pkt.tx_acked * 7;
326 
327 	spin_lock_irqsave(&session->skb_queue.lock, flags);
328 	do_skb = skb_peek(&session->skb_queue);
329 	do_skcb = j1939_skb_to_cb(do_skb);
330 
331 	if ((do_skcb->offset + do_skb->len) < offset_start) {
332 		__skb_unlink(do_skb, &session->skb_queue);
333 		/* drop ref taken in j1939_session_skb_queue() */
334 		skb_unref(do_skb);
335 
336 		kfree_skb(do_skb);
337 	}
338 	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
339 }
340 
341 void j1939_session_skb_queue(struct j1939_session *session,
342 			     struct sk_buff *skb)
343 {
344 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
345 	struct j1939_priv *priv = session->priv;
346 
347 	j1939_ac_fixup(priv, skb);
348 
349 	if (j1939_address_is_unicast(skcb->addr.da) &&
350 	    priv->ents[skcb->addr.da].nusers)
351 		skcb->flags |= J1939_ECU_LOCAL_DST;
352 
353 	skcb->flags |= J1939_ECU_LOCAL_SRC;
354 
355 	skb_get(skb);
356 	skb_queue_tail(&session->skb_queue, skb);
357 }
358 
359 static struct
360 sk_buff *j1939_session_skb_get_by_offset(struct j1939_session *session,
361 					 unsigned int offset_start)
362 {
363 	struct j1939_priv *priv = session->priv;
364 	struct j1939_sk_buff_cb *do_skcb;
365 	struct sk_buff *skb = NULL;
366 	struct sk_buff *do_skb;
367 	unsigned long flags;
368 
369 	spin_lock_irqsave(&session->skb_queue.lock, flags);
370 	skb_queue_walk(&session->skb_queue, do_skb) {
371 		do_skcb = j1939_skb_to_cb(do_skb);
372 
373 		if (offset_start >= do_skcb->offset &&
374 		    offset_start < (do_skcb->offset + do_skb->len)) {
375 			skb = do_skb;
376 		}
377 	}
378 
379 	if (skb)
380 		skb_get(skb);
381 
382 	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
383 
384 	if (!skb)
385 		netdev_dbg(priv->ndev, "%s: 0x%p: no skb found for start: %i, queue size: %i\n",
386 			   __func__, session, offset_start,
387 			   skb_queue_len(&session->skb_queue));
388 
389 	return skb;
390 }
391 
392 static struct sk_buff *j1939_session_skb_get(struct j1939_session *session)
393 {
394 	unsigned int offset_start;
395 
396 	offset_start = session->pkt.dpo * 7;
397 	return j1939_session_skb_get_by_offset(session, offset_start);
398 }
399 
400 /* see if we are receiver
401  * returns 0 for broadcasts, although we will receive them
402  */
403 static inline int j1939_tp_im_receiver(const struct j1939_sk_buff_cb *skcb)
404 {
405 	return skcb->flags & J1939_ECU_LOCAL_DST;
406 }
407 
408 /* see if we are sender */
409 static inline int j1939_tp_im_transmitter(const struct j1939_sk_buff_cb *skcb)
410 {
411 	return skcb->flags & J1939_ECU_LOCAL_SRC;
412 }
413 
414 /* see if we are involved as either receiver or transmitter */
415 static int j1939_tp_im_involved(const struct j1939_sk_buff_cb *skcb, bool swap)
416 {
417 	if (swap)
418 		return j1939_tp_im_receiver(skcb);
419 	else
420 		return j1939_tp_im_transmitter(skcb);
421 }
422 
423 static int j1939_tp_im_involved_anydir(struct j1939_sk_buff_cb *skcb)
424 {
425 	return skcb->flags & (J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
426 }
427 
428 /* extract pgn from flow-ctl message */
429 static inline pgn_t j1939_xtp_ctl_to_pgn(const u8 *dat)
430 {
431 	pgn_t pgn;
432 
433 	pgn = (dat[7] << 16) | (dat[6] << 8) | (dat[5] << 0);
434 	if (j1939_pgn_is_pdu1(pgn))
435 		pgn &= 0xffff00;
436 	return pgn;
437 }
438 
439 static inline unsigned int j1939_tp_ctl_to_size(const u8 *dat)
440 {
441 	return (dat[2] << 8) + (dat[1] << 0);
442 }
443 
444 static inline unsigned int j1939_etp_ctl_to_packet(const u8 *dat)
445 {
446 	return (dat[4] << 16) | (dat[3] << 8) | (dat[2] << 0);
447 }
448 
449 static inline unsigned int j1939_etp_ctl_to_size(const u8 *dat)
450 {
451 	return (dat[4] << 24) | (dat[3] << 16) |
452 		(dat[2] << 8) | (dat[1] << 0);
453 }
454 
455 /* find existing session:
456  * reverse: swap cb's src & dst
457  * there is no problem with matching broadcasts, since
458  * broadcasts (no dst, no da) would never call this
459  * with reverse == true
460  */
461 static bool j1939_session_match(struct j1939_addr *se_addr,
462 				struct j1939_addr *sk_addr, bool reverse)
463 {
464 	if (se_addr->type != sk_addr->type)
465 		return false;
466 
467 	if (reverse) {
468 		if (se_addr->src_name) {
469 			if (se_addr->src_name != sk_addr->dst_name)
470 				return false;
471 		} else if (se_addr->sa != sk_addr->da) {
472 			return false;
473 		}
474 
475 		if (se_addr->dst_name) {
476 			if (se_addr->dst_name != sk_addr->src_name)
477 				return false;
478 		} else if (se_addr->da != sk_addr->sa) {
479 			return false;
480 		}
481 	} else {
482 		if (se_addr->src_name) {
483 			if (se_addr->src_name != sk_addr->src_name)
484 				return false;
485 		} else if (se_addr->sa != sk_addr->sa) {
486 			return false;
487 		}
488 
489 		if (se_addr->dst_name) {
490 			if (se_addr->dst_name != sk_addr->dst_name)
491 				return false;
492 		} else if (se_addr->da != sk_addr->da) {
493 			return false;
494 		}
495 	}
496 
497 	return true;
498 }
499 
500 static struct
501 j1939_session *j1939_session_get_by_addr_locked(struct j1939_priv *priv,
502 						struct list_head *root,
503 						struct j1939_addr *addr,
504 						bool reverse, bool transmitter)
505 {
506 	struct j1939_session *session;
507 
508 	lockdep_assert_held(&priv->active_session_list_lock);
509 
510 	list_for_each_entry(session, root, active_session_list_entry) {
511 		j1939_session_get(session);
512 		if (j1939_session_match(&session->skcb.addr, addr, reverse) &&
513 		    session->transmission == transmitter)
514 			return session;
515 		j1939_session_put(session);
516 	}
517 
518 	return NULL;
519 }
520 
521 static struct
522 j1939_session *j1939_session_get_simple(struct j1939_priv *priv,
523 					struct sk_buff *skb)
524 {
525 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
526 	struct j1939_session *session;
527 
528 	lockdep_assert_held(&priv->active_session_list_lock);
529 
530 	list_for_each_entry(session, &priv->active_session_list,
531 			    active_session_list_entry) {
532 		j1939_session_get(session);
533 		if (session->skcb.addr.type == J1939_SIMPLE &&
534 		    session->tskey == skcb->tskey && session->sk == skb->sk)
535 			return session;
536 		j1939_session_put(session);
537 	}
538 
539 	return NULL;
540 }
541 
542 static struct
543 j1939_session *j1939_session_get_by_addr(struct j1939_priv *priv,
544 					 struct j1939_addr *addr,
545 					 bool reverse, bool transmitter)
546 {
547 	struct j1939_session *session;
548 
549 	j1939_session_list_lock(priv);
550 	session = j1939_session_get_by_addr_locked(priv,
551 						   &priv->active_session_list,
552 						   addr, reverse, transmitter);
553 	j1939_session_list_unlock(priv);
554 
555 	return session;
556 }
557 
558 static void j1939_skbcb_swap(struct j1939_sk_buff_cb *skcb)
559 {
560 	u8 tmp = 0;
561 
562 	swap(skcb->addr.dst_name, skcb->addr.src_name);
563 	swap(skcb->addr.da, skcb->addr.sa);
564 
565 	/* swap SRC and DST flags, leave other untouched */
566 	if (skcb->flags & J1939_ECU_LOCAL_SRC)
567 		tmp |= J1939_ECU_LOCAL_DST;
568 	if (skcb->flags & J1939_ECU_LOCAL_DST)
569 		tmp |= J1939_ECU_LOCAL_SRC;
570 	skcb->flags &= ~(J1939_ECU_LOCAL_SRC | J1939_ECU_LOCAL_DST);
571 	skcb->flags |= tmp;
572 }
573 
574 static struct
575 sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv,
576 			     const struct j1939_sk_buff_cb *re_skcb,
577 			     bool ctl,
578 			     bool swap_src_dst)
579 {
580 	struct sk_buff *skb;
581 	struct j1939_sk_buff_cb *skcb;
582 
583 	skb = alloc_skb(sizeof(struct can_frame) + sizeof(struct can_skb_priv),
584 			GFP_ATOMIC);
585 	if (unlikely(!skb))
586 		return ERR_PTR(-ENOMEM);
587 
588 	skb->dev = priv->ndev;
589 	can_skb_reserve(skb);
590 	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
591 	can_skb_prv(skb)->skbcnt = 0;
592 	/* reserve CAN header */
593 	skb_reserve(skb, offsetof(struct can_frame, data));
594 
595 	memcpy(skb->cb, re_skcb, sizeof(skb->cb));
596 	skcb = j1939_skb_to_cb(skb);
597 	if (swap_src_dst)
598 		j1939_skbcb_swap(skcb);
599 
600 	if (ctl) {
601 		if (skcb->addr.type == J1939_ETP)
602 			skcb->addr.pgn = J1939_ETP_PGN_CTL;
603 		else
604 			skcb->addr.pgn = J1939_TP_PGN_CTL;
605 	} else {
606 		if (skcb->addr.type == J1939_ETP)
607 			skcb->addr.pgn = J1939_ETP_PGN_DAT;
608 		else
609 			skcb->addr.pgn = J1939_TP_PGN_DAT;
610 	}
611 
612 	return skb;
613 }
614 
615 /* TP transmit packet functions */
616 static int j1939_tp_tx_dat(struct j1939_session *session,
617 			   const u8 *dat, int len)
618 {
619 	struct j1939_priv *priv = session->priv;
620 	struct sk_buff *skb;
621 
622 	skb = j1939_tp_tx_dat_new(priv, &session->skcb,
623 				  false, false);
624 	if (IS_ERR(skb))
625 		return PTR_ERR(skb);
626 
627 	skb_put_data(skb, dat, len);
628 	if (j1939_tp_padding && len < 8)
629 		memset(skb_put(skb, 8 - len), 0xff, 8 - len);
630 
631 	return j1939_send_one(priv, skb);
632 }
633 
634 static int j1939_xtp_do_tx_ctl(struct j1939_priv *priv,
635 			       const struct j1939_sk_buff_cb *re_skcb,
636 			       bool swap_src_dst, pgn_t pgn, const u8 *dat)
637 {
638 	struct sk_buff *skb;
639 	u8 *skdat;
640 
641 	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
642 		return 0;
643 
644 	skb = j1939_tp_tx_dat_new(priv, re_skcb, true, swap_src_dst);
645 	if (IS_ERR(skb))
646 		return PTR_ERR(skb);
647 
648 	skdat = skb_put(skb, 8);
649 	memcpy(skdat, dat, 5);
650 	skdat[5] = (pgn >> 0);
651 	skdat[6] = (pgn >> 8);
652 	skdat[7] = (pgn >> 16);
653 
654 	return j1939_send_one(priv, skb);
655 }
656 
657 static inline int j1939_tp_tx_ctl(struct j1939_session *session,
658 				  bool swap_src_dst, const u8 *dat)
659 {
660 	struct j1939_priv *priv = session->priv;
661 
662 	return j1939_xtp_do_tx_ctl(priv, &session->skcb,
663 				   swap_src_dst,
664 				   session->skcb.addr.pgn, dat);
665 }
666 
667 static int j1939_xtp_tx_abort(struct j1939_priv *priv,
668 			      const struct j1939_sk_buff_cb *re_skcb,
669 			      bool swap_src_dst,
670 			      enum j1939_xtp_abort err,
671 			      pgn_t pgn)
672 {
673 	u8 dat[5];
674 
675 	if (!j1939_tp_im_involved(re_skcb, swap_src_dst))
676 		return 0;
677 
678 	memset(dat, 0xff, sizeof(dat));
679 	dat[0] = J1939_TP_CMD_ABORT;
680 	dat[1] = err;
681 	return j1939_xtp_do_tx_ctl(priv, re_skcb, swap_src_dst, pgn, dat);
682 }
683 
684 void j1939_tp_schedule_txtimer(struct j1939_session *session, int msec)
685 {
686 	j1939_session_get(session);
687 	hrtimer_start(&session->txtimer, ms_to_ktime(msec),
688 		      HRTIMER_MODE_REL_SOFT);
689 }
690 
691 static inline void j1939_tp_set_rxtimeout(struct j1939_session *session,
692 					  int msec)
693 {
694 	j1939_session_rxtimer_cancel(session);
695 	j1939_session_get(session);
696 	hrtimer_start(&session->rxtimer, ms_to_ktime(msec),
697 		      HRTIMER_MODE_REL_SOFT);
698 }
699 
700 static int j1939_session_tx_rts(struct j1939_session *session)
701 {
702 	u8 dat[8];
703 	int ret;
704 
705 	memset(dat, 0xff, sizeof(dat));
706 
707 	dat[1] = (session->total_message_size >> 0);
708 	dat[2] = (session->total_message_size >> 8);
709 	dat[3] = session->pkt.total;
710 
711 	if (session->skcb.addr.type == J1939_ETP) {
712 		dat[0] = J1939_ETP_CMD_RTS;
713 		dat[1] = (session->total_message_size >> 0);
714 		dat[2] = (session->total_message_size >> 8);
715 		dat[3] = (session->total_message_size >> 16);
716 		dat[4] = (session->total_message_size >> 24);
717 	} else if (j1939_cb_is_broadcast(&session->skcb)) {
718 		dat[0] = J1939_TP_CMD_BAM;
719 		/* fake cts for broadcast */
720 		session->pkt.tx = 0;
721 	} else {
722 		dat[0] = J1939_TP_CMD_RTS;
723 		dat[4] = dat[3];
724 	}
725 
726 	if (dat[0] == session->last_txcmd)
727 		/* done already */
728 		return 0;
729 
730 	ret = j1939_tp_tx_ctl(session, false, dat);
731 	if (ret < 0)
732 		return ret;
733 
734 	session->last_txcmd = dat[0];
735 	if (dat[0] == J1939_TP_CMD_BAM) {
736 		j1939_tp_schedule_txtimer(session, 50);
737 		j1939_tp_set_rxtimeout(session, 250);
738 	} else {
739 		j1939_tp_set_rxtimeout(session, 1250);
740 	}
741 
742 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
743 
744 	return 0;
745 }
746 
747 static int j1939_session_tx_dpo(struct j1939_session *session)
748 {
749 	unsigned int pkt;
750 	u8 dat[8];
751 	int ret;
752 
753 	memset(dat, 0xff, sizeof(dat));
754 
755 	dat[0] = J1939_ETP_CMD_DPO;
756 	session->pkt.dpo = session->pkt.tx_acked;
757 	pkt = session->pkt.dpo;
758 	dat[1] = session->pkt.last - session->pkt.tx_acked;
759 	dat[2] = (pkt >> 0);
760 	dat[3] = (pkt >> 8);
761 	dat[4] = (pkt >> 16);
762 
763 	ret = j1939_tp_tx_ctl(session, false, dat);
764 	if (ret < 0)
765 		return ret;
766 
767 	session->last_txcmd = dat[0];
768 	j1939_tp_set_rxtimeout(session, 1250);
769 	session->pkt.tx = session->pkt.tx_acked;
770 
771 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
772 
773 	return 0;
774 }
775 
776 static int j1939_session_tx_dat(struct j1939_session *session)
777 {
778 	struct j1939_priv *priv = session->priv;
779 	struct j1939_sk_buff_cb *skcb;
780 	int offset, pkt_done, pkt_end;
781 	unsigned int len, pdelay;
782 	struct sk_buff *se_skb;
783 	const u8 *tpdat;
784 	int ret = 0;
785 	u8 dat[8];
786 
787 	se_skb = j1939_session_skb_get_by_offset(session, session->pkt.tx * 7);
788 	if (!se_skb)
789 		return -ENOBUFS;
790 
791 	skcb = j1939_skb_to_cb(se_skb);
792 	tpdat = se_skb->data;
793 	ret = 0;
794 	pkt_done = 0;
795 	if (session->skcb.addr.type != J1939_ETP &&
796 	    j1939_cb_is_broadcast(&session->skcb))
797 		pkt_end = session->pkt.total;
798 	else
799 		pkt_end = session->pkt.last;
800 
801 	while (session->pkt.tx < pkt_end) {
802 		dat[0] = session->pkt.tx - session->pkt.dpo + 1;
803 		offset = (session->pkt.tx * 7) - skcb->offset;
804 		len =  se_skb->len - offset;
805 		if (len > 7)
806 			len = 7;
807 
808 		if (offset + len > se_skb->len) {
809 			netdev_err_once(priv->ndev,
810 					"%s: 0x%p: requested data outside of queued buffer: offset %i, len %i, pkt.tx: %i\n",
811 					__func__, session, skcb->offset, se_skb->len , session->pkt.tx);
812 			ret = -EOVERFLOW;
813 			goto out_free;
814 		}
815 
816 		if (!len) {
817 			ret = -ENOBUFS;
818 			break;
819 		}
820 
821 		memcpy(&dat[1], &tpdat[offset], len);
822 		ret = j1939_tp_tx_dat(session, dat, len + 1);
823 		if (ret < 0) {
824 			/* ENOBUS == CAN interface TX queue is full */
825 			if (ret != -ENOBUFS)
826 				netdev_alert(priv->ndev,
827 					     "%s: 0x%p: queue data error: %i\n",
828 					     __func__, session, ret);
829 			break;
830 		}
831 
832 		session->last_txcmd = 0xff;
833 		pkt_done++;
834 		session->pkt.tx++;
835 		pdelay = j1939_cb_is_broadcast(&session->skcb) ? 50 :
836 			j1939_tp_packet_delay;
837 
838 		if (session->pkt.tx < session->pkt.total && pdelay) {
839 			j1939_tp_schedule_txtimer(session, pdelay);
840 			break;
841 		}
842 	}
843 
844 	if (pkt_done)
845 		j1939_tp_set_rxtimeout(session, 250);
846 
847  out_free:
848 	if (ret)
849 		kfree_skb(se_skb);
850 	else
851 		consume_skb(se_skb);
852 
853 	return ret;
854 }
855 
856 static int j1939_xtp_txnext_transmiter(struct j1939_session *session)
857 {
858 	struct j1939_priv *priv = session->priv;
859 	int ret = 0;
860 
861 	if (!j1939_tp_im_transmitter(&session->skcb)) {
862 		netdev_alert(priv->ndev, "%s: 0x%p: called by not transmitter!\n",
863 			     __func__, session);
864 		return -EINVAL;
865 	}
866 
867 	switch (session->last_cmd) {
868 	case 0:
869 		ret = j1939_session_tx_rts(session);
870 		break;
871 
872 	case J1939_ETP_CMD_CTS:
873 		if (session->last_txcmd != J1939_ETP_CMD_DPO) {
874 			ret = j1939_session_tx_dpo(session);
875 			if (ret)
876 				return ret;
877 		}
878 
879 		fallthrough;
880 	case J1939_TP_CMD_CTS:
881 	case 0xff: /* did some data */
882 	case J1939_ETP_CMD_DPO:
883 	case J1939_TP_CMD_BAM:
884 		ret = j1939_session_tx_dat(session);
885 
886 		break;
887 	default:
888 		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
889 			     __func__, session, session->last_cmd);
890 	}
891 
892 	return ret;
893 }
894 
895 static int j1939_session_tx_cts(struct j1939_session *session)
896 {
897 	struct j1939_priv *priv = session->priv;
898 	unsigned int pkt, len;
899 	int ret;
900 	u8 dat[8];
901 
902 	if (!j1939_sk_recv_match(priv, &session->skcb))
903 		return -ENOENT;
904 
905 	len = session->pkt.total - session->pkt.rx;
906 	len = min3(len, session->pkt.block, j1939_tp_block ?: 255);
907 	memset(dat, 0xff, sizeof(dat));
908 
909 	if (session->skcb.addr.type == J1939_ETP) {
910 		pkt = session->pkt.rx + 1;
911 		dat[0] = J1939_ETP_CMD_CTS;
912 		dat[1] = len;
913 		dat[2] = (pkt >> 0);
914 		dat[3] = (pkt >> 8);
915 		dat[4] = (pkt >> 16);
916 	} else {
917 		dat[0] = J1939_TP_CMD_CTS;
918 		dat[1] = len;
919 		dat[2] = session->pkt.rx + 1;
920 	}
921 
922 	if (dat[0] == session->last_txcmd)
923 		/* done already */
924 		return 0;
925 
926 	ret = j1939_tp_tx_ctl(session, true, dat);
927 	if (ret < 0)
928 		return ret;
929 
930 	if (len)
931 		/* only mark cts done when len is set */
932 		session->last_txcmd = dat[0];
933 	j1939_tp_set_rxtimeout(session, 1250);
934 
935 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
936 
937 	return 0;
938 }
939 
940 static int j1939_session_tx_eoma(struct j1939_session *session)
941 {
942 	struct j1939_priv *priv = session->priv;
943 	u8 dat[8];
944 	int ret;
945 
946 	if (!j1939_sk_recv_match(priv, &session->skcb))
947 		return -ENOENT;
948 
949 	memset(dat, 0xff, sizeof(dat));
950 
951 	if (session->skcb.addr.type == J1939_ETP) {
952 		dat[0] = J1939_ETP_CMD_EOMA;
953 		dat[1] = session->total_message_size >> 0;
954 		dat[2] = session->total_message_size >> 8;
955 		dat[3] = session->total_message_size >> 16;
956 		dat[4] = session->total_message_size >> 24;
957 	} else {
958 		dat[0] = J1939_TP_CMD_EOMA;
959 		dat[1] = session->total_message_size;
960 		dat[2] = session->total_message_size >> 8;
961 		dat[3] = session->pkt.total;
962 	}
963 
964 	if (dat[0] == session->last_txcmd)
965 		/* done already */
966 		return 0;
967 
968 	ret = j1939_tp_tx_ctl(session, true, dat);
969 	if (ret < 0)
970 		return ret;
971 
972 	session->last_txcmd = dat[0];
973 
974 	/* wait for the EOMA packet to come in */
975 	j1939_tp_set_rxtimeout(session, 1250);
976 
977 	netdev_dbg(session->priv->ndev, "%p: 0x%p\n", __func__, session);
978 
979 	return 0;
980 }
981 
982 static int j1939_xtp_txnext_receiver(struct j1939_session *session)
983 {
984 	struct j1939_priv *priv = session->priv;
985 	int ret = 0;
986 
987 	if (!j1939_tp_im_receiver(&session->skcb)) {
988 		netdev_alert(priv->ndev, "%s: 0x%p: called by not receiver!\n",
989 			     __func__, session);
990 		return -EINVAL;
991 	}
992 
993 	switch (session->last_cmd) {
994 	case J1939_TP_CMD_RTS:
995 	case J1939_ETP_CMD_RTS:
996 		ret = j1939_session_tx_cts(session);
997 		break;
998 
999 	case J1939_ETP_CMD_CTS:
1000 	case J1939_TP_CMD_CTS:
1001 	case 0xff: /* did some data */
1002 	case J1939_ETP_CMD_DPO:
1003 		if ((session->skcb.addr.type == J1939_TP &&
1004 		     j1939_cb_is_broadcast(&session->skcb)))
1005 			break;
1006 
1007 		if (session->pkt.rx >= session->pkt.total) {
1008 			ret = j1939_session_tx_eoma(session);
1009 		} else if (session->pkt.rx >= session->pkt.last) {
1010 			session->last_txcmd = 0;
1011 			ret = j1939_session_tx_cts(session);
1012 		}
1013 		break;
1014 	default:
1015 		netdev_alert(priv->ndev, "%s: 0x%p: unexpected last_cmd: %x\n",
1016 			     __func__, session, session->last_cmd);
1017 	}
1018 
1019 	return ret;
1020 }
1021 
1022 static int j1939_simple_txnext(struct j1939_session *session)
1023 {
1024 	struct j1939_priv *priv = session->priv;
1025 	struct sk_buff *se_skb = j1939_session_skb_get(session);
1026 	struct sk_buff *skb;
1027 	int ret;
1028 
1029 	if (!se_skb)
1030 		return 0;
1031 
1032 	skb = skb_clone(se_skb, GFP_ATOMIC);
1033 	if (!skb) {
1034 		ret = -ENOMEM;
1035 		goto out_free;
1036 	}
1037 
1038 	can_skb_set_owner(skb, se_skb->sk);
1039 
1040 	j1939_tp_set_rxtimeout(session, J1939_SIMPLE_ECHO_TIMEOUT_MS);
1041 
1042 	ret = j1939_send_one(priv, skb);
1043 	if (ret)
1044 		goto out_free;
1045 
1046 	j1939_sk_errqueue(session, J1939_ERRQUEUE_SCHED);
1047 	j1939_sk_queue_activate_next(session);
1048 
1049  out_free:
1050 	if (ret)
1051 		kfree_skb(se_skb);
1052 	else
1053 		consume_skb(se_skb);
1054 
1055 	return ret;
1056 }
1057 
1058 static bool j1939_session_deactivate_locked(struct j1939_session *session)
1059 {
1060 	bool active = false;
1061 
1062 	lockdep_assert_held(&session->priv->active_session_list_lock);
1063 
1064 	if (session->state >= J1939_SESSION_ACTIVE &&
1065 	    session->state < J1939_SESSION_ACTIVE_MAX) {
1066 		active = true;
1067 
1068 		list_del_init(&session->active_session_list_entry);
1069 		session->state = J1939_SESSION_DONE;
1070 		j1939_session_put(session);
1071 	}
1072 
1073 	return active;
1074 }
1075 
1076 static bool j1939_session_deactivate(struct j1939_session *session)
1077 {
1078 	bool active;
1079 
1080 	j1939_session_list_lock(session->priv);
1081 	active = j1939_session_deactivate_locked(session);
1082 	j1939_session_list_unlock(session->priv);
1083 
1084 	return active;
1085 }
1086 
1087 static void
1088 j1939_session_deactivate_activate_next(struct j1939_session *session)
1089 {
1090 	if (j1939_session_deactivate(session))
1091 		j1939_sk_queue_activate_next(session);
1092 }
1093 
1094 static void __j1939_session_cancel(struct j1939_session *session,
1095 				 enum j1939_xtp_abort err)
1096 {
1097 	struct j1939_priv *priv = session->priv;
1098 
1099 	WARN_ON_ONCE(!err);
1100 	lockdep_assert_held(&session->priv->active_session_list_lock);
1101 
1102 	session->err = j1939_xtp_abort_to_errno(priv, err);
1103 	session->state = J1939_SESSION_WAITING_ABORT;
1104 	/* do not send aborts on incoming broadcasts */
1105 	if (!j1939_cb_is_broadcast(&session->skcb)) {
1106 		j1939_xtp_tx_abort(priv, &session->skcb,
1107 				   !session->transmission,
1108 				   err, session->skcb.addr.pgn);
1109 	}
1110 
1111 	if (session->sk)
1112 		j1939_sk_send_loop_abort(session->sk, session->err);
1113 }
1114 
1115 static void j1939_session_cancel(struct j1939_session *session,
1116 				 enum j1939_xtp_abort err)
1117 {
1118 	j1939_session_list_lock(session->priv);
1119 
1120 	if (session->state >= J1939_SESSION_ACTIVE &&
1121 	    session->state < J1939_SESSION_WAITING_ABORT) {
1122 		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
1123 		__j1939_session_cancel(session, err);
1124 	}
1125 
1126 	j1939_session_list_unlock(session->priv);
1127 }
1128 
1129 static enum hrtimer_restart j1939_tp_txtimer(struct hrtimer *hrtimer)
1130 {
1131 	struct j1939_session *session =
1132 		container_of(hrtimer, struct j1939_session, txtimer);
1133 	struct j1939_priv *priv = session->priv;
1134 	int ret = 0;
1135 
1136 	if (session->skcb.addr.type == J1939_SIMPLE) {
1137 		ret = j1939_simple_txnext(session);
1138 	} else {
1139 		if (session->transmission)
1140 			ret = j1939_xtp_txnext_transmiter(session);
1141 		else
1142 			ret = j1939_xtp_txnext_receiver(session);
1143 	}
1144 
1145 	switch (ret) {
1146 	case -ENOBUFS:
1147 		/* Retry limit is currently arbitrary chosen */
1148 		if (session->tx_retry < J1939_XTP_TX_RETRY_LIMIT) {
1149 			session->tx_retry++;
1150 			j1939_tp_schedule_txtimer(session,
1151 						  10 + prandom_u32_max(16));
1152 		} else {
1153 			netdev_alert(priv->ndev, "%s: 0x%p: tx retry count reached\n",
1154 				     __func__, session);
1155 			session->err = -ENETUNREACH;
1156 			j1939_session_rxtimer_cancel(session);
1157 			j1939_session_deactivate_activate_next(session);
1158 		}
1159 		break;
1160 	case -ENETDOWN:
1161 		/* In this case we should get a netdev_event(), all active
1162 		 * sessions will be cleared by
1163 		 * j1939_cancel_all_active_sessions(). So handle this as an
1164 		 * error, but let j1939_cancel_all_active_sessions() do the
1165 		 * cleanup including propagation of the error to user space.
1166 		 */
1167 		break;
1168 	case -EOVERFLOW:
1169 		j1939_session_cancel(session, J1939_XTP_ABORT_ECTS_TOO_BIG);
1170 		break;
1171 	case 0:
1172 		session->tx_retry = 0;
1173 		break;
1174 	default:
1175 		netdev_alert(priv->ndev, "%s: 0x%p: tx aborted with unknown reason: %i\n",
1176 			     __func__, session, ret);
1177 		if (session->skcb.addr.type != J1939_SIMPLE) {
1178 			j1939_session_cancel(session, J1939_XTP_ABORT_OTHER);
1179 		} else {
1180 			session->err = ret;
1181 			j1939_session_rxtimer_cancel(session);
1182 			j1939_session_deactivate_activate_next(session);
1183 		}
1184 	}
1185 
1186 	j1939_session_put(session);
1187 
1188 	return HRTIMER_NORESTART;
1189 }
1190 
1191 static void j1939_session_completed(struct j1939_session *session)
1192 {
1193 	struct sk_buff *skb;
1194 
1195 	if (!session->transmission) {
1196 		skb = j1939_session_skb_get(session);
1197 		/* distribute among j1939 receivers */
1198 		j1939_sk_recv(session->priv, skb);
1199 		consume_skb(skb);
1200 	}
1201 
1202 	j1939_session_deactivate_activate_next(session);
1203 }
1204 
1205 static enum hrtimer_restart j1939_tp_rxtimer(struct hrtimer *hrtimer)
1206 {
1207 	struct j1939_session *session = container_of(hrtimer,
1208 						     struct j1939_session,
1209 						     rxtimer);
1210 	struct j1939_priv *priv = session->priv;
1211 
1212 	if (session->state == J1939_SESSION_WAITING_ABORT) {
1213 		netdev_alert(priv->ndev, "%s: 0x%p: abort rx timeout. Force session deactivation\n",
1214 			     __func__, session);
1215 
1216 		j1939_session_deactivate_activate_next(session);
1217 
1218 	} else if (session->skcb.addr.type == J1939_SIMPLE) {
1219 		netdev_alert(priv->ndev, "%s: 0x%p: Timeout. Failed to send simple message.\n",
1220 			     __func__, session);
1221 
1222 		/* The message is probably stuck in the CAN controller and can
1223 		 * be send as soon as CAN bus is in working state again.
1224 		 */
1225 		session->err = -ETIME;
1226 		j1939_session_deactivate(session);
1227 	} else {
1228 		netdev_alert(priv->ndev, "%s: 0x%p: rx timeout, send abort\n",
1229 			     __func__, session);
1230 
1231 		j1939_session_list_lock(session->priv);
1232 		if (session->state >= J1939_SESSION_ACTIVE &&
1233 		    session->state < J1939_SESSION_ACTIVE_MAX) {
1234 			j1939_session_get(session);
1235 			hrtimer_start(&session->rxtimer,
1236 				      ms_to_ktime(J1939_XTP_ABORT_TIMEOUT_MS),
1237 				      HRTIMER_MODE_REL_SOFT);
1238 			__j1939_session_cancel(session, J1939_XTP_ABORT_TIMEOUT);
1239 		}
1240 		j1939_session_list_unlock(session->priv);
1241 	}
1242 
1243 	j1939_session_put(session);
1244 
1245 	return HRTIMER_NORESTART;
1246 }
1247 
1248 static bool j1939_xtp_rx_cmd_bad_pgn(struct j1939_session *session,
1249 				     const struct sk_buff *skb)
1250 {
1251 	const struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1252 	pgn_t pgn = j1939_xtp_ctl_to_pgn(skb->data);
1253 	struct j1939_priv *priv = session->priv;
1254 	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
1255 	u8 cmd = skb->data[0];
1256 
1257 	if (session->skcb.addr.pgn == pgn)
1258 		return false;
1259 
1260 	switch (cmd) {
1261 	case J1939_TP_CMD_BAM:
1262 		abort = J1939_XTP_NO_ABORT;
1263 		break;
1264 
1265 	case J1939_ETP_CMD_RTS:
1266 	case J1939_TP_CMD_RTS: /* fall through */
1267 		abort = J1939_XTP_ABORT_BUSY;
1268 		break;
1269 
1270 	case J1939_ETP_CMD_CTS:
1271 	case J1939_TP_CMD_CTS: /* fall through */
1272 		abort = J1939_XTP_ABORT_ECTS_UNXPECTED_PGN;
1273 		break;
1274 
1275 	case J1939_ETP_CMD_DPO:
1276 		abort = J1939_XTP_ABORT_BAD_EDPO_PGN;
1277 		break;
1278 
1279 	case J1939_ETP_CMD_EOMA:
1280 	case J1939_TP_CMD_EOMA: /* fall through */
1281 		abort = J1939_XTP_ABORT_OTHER;
1282 		break;
1283 
1284 	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
1285 		abort = J1939_XTP_NO_ABORT;
1286 		break;
1287 
1288 	default:
1289 		WARN_ON_ONCE(1);
1290 		break;
1291 	}
1292 
1293 	netdev_warn(priv->ndev, "%s: 0x%p: CMD 0x%02x with PGN 0x%05x for running session with different PGN 0x%05x.\n",
1294 		    __func__, session, cmd, pgn, session->skcb.addr.pgn);
1295 	if (abort != J1939_XTP_NO_ABORT)
1296 		j1939_xtp_tx_abort(priv, skcb, true, abort, pgn);
1297 
1298 	return true;
1299 }
1300 
1301 static void j1939_xtp_rx_abort_one(struct j1939_priv *priv, struct sk_buff *skb,
1302 				   bool reverse, bool transmitter)
1303 {
1304 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1305 	struct j1939_session *session;
1306 	u8 abort = skb->data[1];
1307 
1308 	session = j1939_session_get_by_addr(priv, &skcb->addr, reverse,
1309 					    transmitter);
1310 	if (!session)
1311 		return;
1312 
1313 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1314 		goto abort_put;
1315 
1316 	netdev_info(priv->ndev, "%s: 0x%p: 0x%05x: (%u) %s\n", __func__,
1317 		    session, j1939_xtp_ctl_to_pgn(skb->data), abort,
1318 		    j1939_xtp_abort_to_str(abort));
1319 
1320 	j1939_session_timers_cancel(session);
1321 	session->err = j1939_xtp_abort_to_errno(priv, abort);
1322 	if (session->sk)
1323 		j1939_sk_send_loop_abort(session->sk, session->err);
1324 	j1939_session_deactivate_activate_next(session);
1325 
1326 abort_put:
1327 	j1939_session_put(session);
1328 }
1329 
1330 /* abort packets may come in 2 directions */
1331 static void
1332 j1939_xtp_rx_abort(struct j1939_priv *priv, struct sk_buff *skb,
1333 		   bool transmitter)
1334 {
1335 	j1939_xtp_rx_abort_one(priv, skb, false, transmitter);
1336 	j1939_xtp_rx_abort_one(priv, skb, true, transmitter);
1337 }
1338 
1339 static void
1340 j1939_xtp_rx_eoma_one(struct j1939_session *session, struct sk_buff *skb)
1341 {
1342 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1343 	const u8 *dat;
1344 	int len;
1345 
1346 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1347 		return;
1348 
1349 	dat = skb->data;
1350 
1351 	if (skcb->addr.type == J1939_ETP)
1352 		len = j1939_etp_ctl_to_size(dat);
1353 	else
1354 		len = j1939_tp_ctl_to_size(dat);
1355 
1356 	if (session->total_message_size != len) {
1357 		netdev_warn_once(session->priv->ndev,
1358 				 "%s: 0x%p: Incorrect size. Expected: %i; got: %i.\n",
1359 				 __func__, session, session->total_message_size,
1360 				 len);
1361 	}
1362 
1363 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1364 
1365 	session->pkt.tx_acked = session->pkt.total;
1366 	j1939_session_timers_cancel(session);
1367 	/* transmitted without problems */
1368 	j1939_session_completed(session);
1369 }
1370 
1371 static void
1372 j1939_xtp_rx_eoma(struct j1939_priv *priv, struct sk_buff *skb,
1373 		  bool transmitter)
1374 {
1375 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1376 	struct j1939_session *session;
1377 
1378 	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
1379 					    transmitter);
1380 	if (!session)
1381 		return;
1382 
1383 	j1939_xtp_rx_eoma_one(session, skb);
1384 	j1939_session_put(session);
1385 }
1386 
1387 static void
1388 j1939_xtp_rx_cts_one(struct j1939_session *session, struct sk_buff *skb)
1389 {
1390 	enum j1939_xtp_abort err = J1939_XTP_ABORT_FAULT;
1391 	unsigned int pkt;
1392 	const u8 *dat;
1393 
1394 	dat = skb->data;
1395 
1396 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1397 		return;
1398 
1399 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1400 
1401 	if (session->last_cmd == dat[0]) {
1402 		err = J1939_XTP_ABORT_DUP_SEQ;
1403 		goto out_session_cancel;
1404 	}
1405 
1406 	if (session->skcb.addr.type == J1939_ETP)
1407 		pkt = j1939_etp_ctl_to_packet(dat);
1408 	else
1409 		pkt = dat[2];
1410 
1411 	if (!pkt)
1412 		goto out_session_cancel;
1413 	else if (dat[1] > session->pkt.block /* 0xff for etp */)
1414 		goto out_session_cancel;
1415 
1416 	/* set packet counters only when not CTS(0) */
1417 	session->pkt.tx_acked = pkt - 1;
1418 	j1939_session_skb_drop_old(session);
1419 	session->pkt.last = session->pkt.tx_acked + dat[1];
1420 	if (session->pkt.last > session->pkt.total)
1421 		/* safety measure */
1422 		session->pkt.last = session->pkt.total;
1423 	/* TODO: do not set tx here, do it in txtimer */
1424 	session->pkt.tx = session->pkt.tx_acked;
1425 
1426 	session->last_cmd = dat[0];
1427 	if (dat[1]) {
1428 		j1939_tp_set_rxtimeout(session, 1250);
1429 		if (session->transmission) {
1430 			if (session->pkt.tx_acked)
1431 				j1939_sk_errqueue(session,
1432 						  J1939_ERRQUEUE_SCHED);
1433 			j1939_session_txtimer_cancel(session);
1434 			j1939_tp_schedule_txtimer(session, 0);
1435 		}
1436 	} else {
1437 		/* CTS(0) */
1438 		j1939_tp_set_rxtimeout(session, 550);
1439 	}
1440 	return;
1441 
1442  out_session_cancel:
1443 	j1939_session_timers_cancel(session);
1444 	j1939_session_cancel(session, err);
1445 }
1446 
1447 static void
1448 j1939_xtp_rx_cts(struct j1939_priv *priv, struct sk_buff *skb, bool transmitter)
1449 {
1450 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1451 	struct j1939_session *session;
1452 
1453 	session = j1939_session_get_by_addr(priv, &skcb->addr, true,
1454 					    transmitter);
1455 	if (!session)
1456 		return;
1457 	j1939_xtp_rx_cts_one(session, skb);
1458 	j1939_session_put(session);
1459 }
1460 
1461 static struct j1939_session *j1939_session_new(struct j1939_priv *priv,
1462 					       struct sk_buff *skb, size_t size)
1463 {
1464 	struct j1939_session *session;
1465 	struct j1939_sk_buff_cb *skcb;
1466 
1467 	session = kzalloc(sizeof(*session), gfp_any());
1468 	if (!session)
1469 		return NULL;
1470 
1471 	INIT_LIST_HEAD(&session->active_session_list_entry);
1472 	INIT_LIST_HEAD(&session->sk_session_queue_entry);
1473 	kref_init(&session->kref);
1474 
1475 	j1939_priv_get(priv);
1476 	session->priv = priv;
1477 	session->total_message_size = size;
1478 	session->state = J1939_SESSION_NEW;
1479 
1480 	skb_queue_head_init(&session->skb_queue);
1481 	skb_queue_tail(&session->skb_queue, skb);
1482 
1483 	skcb = j1939_skb_to_cb(skb);
1484 	memcpy(&session->skcb, skcb, sizeof(session->skcb));
1485 
1486 	hrtimer_init(&session->txtimer, CLOCK_MONOTONIC,
1487 		     HRTIMER_MODE_REL_SOFT);
1488 	session->txtimer.function = j1939_tp_txtimer;
1489 	hrtimer_init(&session->rxtimer, CLOCK_MONOTONIC,
1490 		     HRTIMER_MODE_REL_SOFT);
1491 	session->rxtimer.function = j1939_tp_rxtimer;
1492 
1493 	netdev_dbg(priv->ndev, "%s: 0x%p: sa: %02x, da: %02x\n",
1494 		   __func__, session, skcb->addr.sa, skcb->addr.da);
1495 
1496 	return session;
1497 }
1498 
1499 static struct
1500 j1939_session *j1939_session_fresh_new(struct j1939_priv *priv,
1501 				       int size,
1502 				       const struct j1939_sk_buff_cb *rel_skcb)
1503 {
1504 	struct sk_buff *skb;
1505 	struct j1939_sk_buff_cb *skcb;
1506 	struct j1939_session *session;
1507 
1508 	skb = alloc_skb(size + sizeof(struct can_skb_priv), GFP_ATOMIC);
1509 	if (unlikely(!skb))
1510 		return NULL;
1511 
1512 	skb->dev = priv->ndev;
1513 	can_skb_reserve(skb);
1514 	can_skb_prv(skb)->ifindex = priv->ndev->ifindex;
1515 	can_skb_prv(skb)->skbcnt = 0;
1516 	skcb = j1939_skb_to_cb(skb);
1517 	memcpy(skcb, rel_skcb, sizeof(*skcb));
1518 
1519 	session = j1939_session_new(priv, skb, size);
1520 	if (!session) {
1521 		kfree_skb(skb);
1522 		return NULL;
1523 	}
1524 
1525 	/* alloc data area */
1526 	skb_put(skb, size);
1527 	/* skb is recounted in j1939_session_new() */
1528 	return session;
1529 }
1530 
1531 int j1939_session_activate(struct j1939_session *session)
1532 {
1533 	struct j1939_priv *priv = session->priv;
1534 	struct j1939_session *active = NULL;
1535 	int ret = 0;
1536 
1537 	j1939_session_list_lock(priv);
1538 	if (session->skcb.addr.type != J1939_SIMPLE)
1539 		active = j1939_session_get_by_addr_locked(priv,
1540 							  &priv->active_session_list,
1541 							  &session->skcb.addr, false,
1542 							  session->transmission);
1543 	if (active) {
1544 		j1939_session_put(active);
1545 		ret = -EAGAIN;
1546 	} else {
1547 		WARN_ON_ONCE(session->state != J1939_SESSION_NEW);
1548 		list_add_tail(&session->active_session_list_entry,
1549 			      &priv->active_session_list);
1550 		j1939_session_get(session);
1551 		session->state = J1939_SESSION_ACTIVE;
1552 
1553 		netdev_dbg(session->priv->ndev, "%s: 0x%p\n",
1554 			   __func__, session);
1555 	}
1556 	j1939_session_list_unlock(priv);
1557 
1558 	return ret;
1559 }
1560 
1561 static struct
1562 j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv,
1563 					    struct sk_buff *skb)
1564 {
1565 	enum j1939_xtp_abort abort = J1939_XTP_NO_ABORT;
1566 	struct j1939_sk_buff_cb skcb = *j1939_skb_to_cb(skb);
1567 	struct j1939_session *session;
1568 	const u8 *dat;
1569 	pgn_t pgn;
1570 	int len;
1571 
1572 	netdev_dbg(priv->ndev, "%s\n", __func__);
1573 
1574 	dat = skb->data;
1575 	pgn = j1939_xtp_ctl_to_pgn(dat);
1576 	skcb.addr.pgn = pgn;
1577 
1578 	if (!j1939_sk_recv_match(priv, &skcb))
1579 		return NULL;
1580 
1581 	if (skcb.addr.type == J1939_ETP) {
1582 		len = j1939_etp_ctl_to_size(dat);
1583 		if (len > J1939_MAX_ETP_PACKET_SIZE)
1584 			abort = J1939_XTP_ABORT_FAULT;
1585 		else if (len > priv->tp_max_packet_size)
1586 			abort = J1939_XTP_ABORT_RESOURCE;
1587 		else if (len <= J1939_MAX_TP_PACKET_SIZE)
1588 			abort = J1939_XTP_ABORT_FAULT;
1589 	} else {
1590 		len = j1939_tp_ctl_to_size(dat);
1591 		if (len > J1939_MAX_TP_PACKET_SIZE)
1592 			abort = J1939_XTP_ABORT_FAULT;
1593 		else if (len > priv->tp_max_packet_size)
1594 			abort = J1939_XTP_ABORT_RESOURCE;
1595 	}
1596 
1597 	if (abort != J1939_XTP_NO_ABORT) {
1598 		j1939_xtp_tx_abort(priv, &skcb, true, abort, pgn);
1599 		return NULL;
1600 	}
1601 
1602 	session = j1939_session_fresh_new(priv, len, &skcb);
1603 	if (!session) {
1604 		j1939_xtp_tx_abort(priv, &skcb, true,
1605 				   J1939_XTP_ABORT_RESOURCE, pgn);
1606 		return NULL;
1607 	}
1608 
1609 	/* initialize the control buffer: plain copy */
1610 	session->pkt.total = (len + 6) / 7;
1611 	session->pkt.block = 0xff;
1612 	if (skcb.addr.type != J1939_ETP) {
1613 		if (dat[3] != session->pkt.total)
1614 			netdev_alert(priv->ndev, "%s: 0x%p: strange total, %u != %u\n",
1615 				     __func__, session, session->pkt.total,
1616 				     dat[3]);
1617 		session->pkt.total = dat[3];
1618 		session->pkt.block = min(dat[3], dat[4]);
1619 	}
1620 
1621 	session->pkt.rx = 0;
1622 	session->pkt.tx = 0;
1623 
1624 	WARN_ON_ONCE(j1939_session_activate(session));
1625 
1626 	return session;
1627 }
1628 
1629 static int j1939_xtp_rx_rts_session_active(struct j1939_session *session,
1630 					   struct sk_buff *skb)
1631 {
1632 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1633 	struct j1939_priv *priv = session->priv;
1634 
1635 	if (!session->transmission) {
1636 		if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1637 			return -EBUSY;
1638 
1639 		/* RTS on active session */
1640 		j1939_session_timers_cancel(session);
1641 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
1642 	}
1643 
1644 	if (session->last_cmd != 0) {
1645 		/* we received a second rts on the same connection */
1646 		netdev_alert(priv->ndev, "%s: 0x%p: connection exists (%02x %02x). last cmd: %x\n",
1647 			     __func__, session, skcb->addr.sa, skcb->addr.da,
1648 			     session->last_cmd);
1649 
1650 		j1939_session_timers_cancel(session);
1651 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
1652 
1653 		return -EBUSY;
1654 	}
1655 
1656 	if (session->skcb.addr.sa != skcb->addr.sa ||
1657 	    session->skcb.addr.da != skcb->addr.da)
1658 		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",
1659 			    __func__, session,
1660 			    session->skcb.addr.sa, skcb->addr.sa,
1661 			    session->skcb.addr.da, skcb->addr.da);
1662 	/* make sure 'sa' & 'da' are correct !
1663 	 * They may be 'not filled in yet' for sending
1664 	 * skb's, since they did not pass the Address Claim ever.
1665 	 */
1666 	session->skcb.addr.sa = skcb->addr.sa;
1667 	session->skcb.addr.da = skcb->addr.da;
1668 
1669 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1670 
1671 	return 0;
1672 }
1673 
1674 static void j1939_xtp_rx_rts(struct j1939_priv *priv, struct sk_buff *skb,
1675 			     bool transmitter)
1676 {
1677 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1678 	struct j1939_session *session;
1679 	u8 cmd = skb->data[0];
1680 
1681 	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1682 					    transmitter);
1683 
1684 	if (!session) {
1685 		if (transmitter) {
1686 			/* If we're the transmitter and this function is called,
1687 			 * we received our own RTS. A session has already been
1688 			 * created.
1689 			 *
1690 			 * For some reasons however it might have been destroyed
1691 			 * already. So don't create a new one here (using
1692 			 * "j1939_xtp_rx_rts_session_new()") as this will be a
1693 			 * receiver session.
1694 			 *
1695 			 * The reasons the session is already destroyed might
1696 			 * be:
1697 			 * - user space closed socket was and the session was
1698 			 *   aborted
1699 			 * - session was aborted due to external abort message
1700 			 */
1701 			return;
1702 		}
1703 		session = j1939_xtp_rx_rts_session_new(priv, skb);
1704 		if (!session) {
1705 			if (cmd == J1939_TP_CMD_BAM && j1939_sk_recv_match(priv, skcb))
1706 				netdev_info(priv->ndev, "%s: failed to create TP BAM session\n",
1707 					    __func__);
1708 			return;
1709 		}
1710 	} else {
1711 		if (j1939_xtp_rx_rts_session_active(session, skb)) {
1712 			j1939_session_put(session);
1713 			return;
1714 		}
1715 	}
1716 	session->last_cmd = cmd;
1717 
1718 	if (cmd == J1939_TP_CMD_BAM) {
1719 		if (!session->transmission)
1720 			j1939_tp_set_rxtimeout(session, 750);
1721 	} else {
1722 		if (!session->transmission) {
1723 			j1939_session_txtimer_cancel(session);
1724 			j1939_tp_schedule_txtimer(session, 0);
1725 		}
1726 		j1939_tp_set_rxtimeout(session, 1250);
1727 	}
1728 
1729 	j1939_session_put(session);
1730 }
1731 
1732 static void j1939_xtp_rx_dpo_one(struct j1939_session *session,
1733 				 struct sk_buff *skb)
1734 {
1735 	const u8 *dat = skb->data;
1736 
1737 	if (j1939_xtp_rx_cmd_bad_pgn(session, skb))
1738 		return;
1739 
1740 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
1741 
1742 	/* transmitted without problems */
1743 	session->pkt.dpo = j1939_etp_ctl_to_packet(skb->data);
1744 	session->last_cmd = dat[0];
1745 	j1939_tp_set_rxtimeout(session, 750);
1746 }
1747 
1748 static void j1939_xtp_rx_dpo(struct j1939_priv *priv, struct sk_buff *skb,
1749 			     bool transmitter)
1750 {
1751 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1752 	struct j1939_session *session;
1753 
1754 	session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1755 					    transmitter);
1756 	if (!session) {
1757 		netdev_info(priv->ndev,
1758 			    "%s: no connection found\n", __func__);
1759 		return;
1760 	}
1761 
1762 	j1939_xtp_rx_dpo_one(session, skb);
1763 	j1939_session_put(session);
1764 }
1765 
1766 static void j1939_xtp_rx_dat_one(struct j1939_session *session,
1767 				 struct sk_buff *skb)
1768 {
1769 	struct j1939_priv *priv = session->priv;
1770 	struct j1939_sk_buff_cb *skcb;
1771 	struct sk_buff *se_skb = NULL;
1772 	const u8 *dat;
1773 	u8 *tpdat;
1774 	int offset;
1775 	int nbytes;
1776 	bool final = false;
1777 	bool remain = false;
1778 	bool do_cts_eoma = false;
1779 	int packet;
1780 
1781 	skcb = j1939_skb_to_cb(skb);
1782 	dat = skb->data;
1783 	if (skb->len <= 1)
1784 		/* makes no sense */
1785 		goto out_session_cancel;
1786 
1787 	switch (session->last_cmd) {
1788 	case 0xff:
1789 		break;
1790 	case J1939_ETP_CMD_DPO:
1791 		if (skcb->addr.type == J1939_ETP)
1792 			break;
1793 		fallthrough;
1794 	case J1939_TP_CMD_BAM:
1795 	case J1939_TP_CMD_CTS: /* fall through */
1796 		if (skcb->addr.type != J1939_ETP)
1797 			break;
1798 		fallthrough;
1799 	default:
1800 		netdev_info(priv->ndev, "%s: 0x%p: last %02x\n", __func__,
1801 			    session, session->last_cmd);
1802 		goto out_session_cancel;
1803 	}
1804 
1805 	packet = (dat[0] - 1 + session->pkt.dpo);
1806 	if (packet > session->pkt.total ||
1807 	    (session->pkt.rx + 1) > session->pkt.total) {
1808 		netdev_info(priv->ndev, "%s: 0x%p: should have been completed\n",
1809 			    __func__, session);
1810 		goto out_session_cancel;
1811 	}
1812 
1813 	se_skb = j1939_session_skb_get_by_offset(session, packet * 7);
1814 	if (!se_skb) {
1815 		netdev_warn(priv->ndev, "%s: 0x%p: no skb found\n", __func__,
1816 			    session);
1817 		goto out_session_cancel;
1818 	}
1819 
1820 	skcb = j1939_skb_to_cb(se_skb);
1821 	offset = packet * 7 - skcb->offset;
1822 	nbytes = se_skb->len - offset;
1823 	if (nbytes > 7)
1824 		nbytes = 7;
1825 	if (nbytes <= 0 || (nbytes + 1) > skb->len) {
1826 		netdev_info(priv->ndev, "%s: 0x%p: nbytes %i, len %i\n",
1827 			    __func__, session, nbytes, skb->len);
1828 		goto out_session_cancel;
1829 	}
1830 
1831 	tpdat = se_skb->data;
1832 	if (!session->transmission) {
1833 		memcpy(&tpdat[offset], &dat[1], nbytes);
1834 	} else {
1835 		int err;
1836 
1837 		err = memcmp(&tpdat[offset], &dat[1], nbytes);
1838 		if (err)
1839 			netdev_err_once(priv->ndev,
1840 					"%s: 0x%p: Data of RX-looped back packet (%*ph) doesn't match TX data (%*ph)!\n",
1841 					__func__, session,
1842 					nbytes, &dat[1],
1843 					nbytes, &tpdat[offset]);
1844 	}
1845 
1846 	if (packet == session->pkt.rx)
1847 		session->pkt.rx++;
1848 
1849 	if (skcb->addr.type != J1939_ETP &&
1850 	    j1939_cb_is_broadcast(&session->skcb)) {
1851 		if (session->pkt.rx >= session->pkt.total)
1852 			final = true;
1853 		else
1854 			remain = true;
1855 	} else {
1856 		/* never final, an EOMA must follow */
1857 		if (session->pkt.rx >= session->pkt.last)
1858 			do_cts_eoma = true;
1859 	}
1860 
1861 	if (final) {
1862 		j1939_session_timers_cancel(session);
1863 		j1939_session_completed(session);
1864 	} else if (remain) {
1865 		if (!session->transmission)
1866 			j1939_tp_set_rxtimeout(session, 750);
1867 	} else if (do_cts_eoma) {
1868 		j1939_tp_set_rxtimeout(session, 1250);
1869 		if (!session->transmission)
1870 			j1939_tp_schedule_txtimer(session, 0);
1871 	} else {
1872 		j1939_tp_set_rxtimeout(session, 250);
1873 	}
1874 	session->last_cmd = 0xff;
1875 	consume_skb(se_skb);
1876 	j1939_session_put(session);
1877 
1878 	return;
1879 
1880  out_session_cancel:
1881 	kfree_skb(se_skb);
1882 	j1939_session_timers_cancel(session);
1883 	j1939_session_cancel(session, J1939_XTP_ABORT_FAULT);
1884 	j1939_session_put(session);
1885 }
1886 
1887 static void j1939_xtp_rx_dat(struct j1939_priv *priv, struct sk_buff *skb)
1888 {
1889 	struct j1939_sk_buff_cb *skcb;
1890 	struct j1939_session *session;
1891 
1892 	skcb = j1939_skb_to_cb(skb);
1893 
1894 	if (j1939_tp_im_transmitter(skcb)) {
1895 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1896 						    true);
1897 		if (!session)
1898 			netdev_info(priv->ndev, "%s: no tx connection found\n",
1899 				    __func__);
1900 		else
1901 			j1939_xtp_rx_dat_one(session, skb);
1902 	}
1903 
1904 	if (j1939_tp_im_receiver(skcb)) {
1905 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1906 						    false);
1907 		if (!session)
1908 			netdev_info(priv->ndev, "%s: no rx connection found\n",
1909 				    __func__);
1910 		else
1911 			j1939_xtp_rx_dat_one(session, skb);
1912 	}
1913 
1914 	if (j1939_cb_is_broadcast(skcb)) {
1915 		session = j1939_session_get_by_addr(priv, &skcb->addr, false,
1916 						    false);
1917 		if (session)
1918 			j1939_xtp_rx_dat_one(session, skb);
1919 	}
1920 }
1921 
1922 /* j1939 main intf */
1923 struct j1939_session *j1939_tp_send(struct j1939_priv *priv,
1924 				    struct sk_buff *skb, size_t size)
1925 {
1926 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1927 	struct j1939_session *session;
1928 	int ret;
1929 
1930 	if (skcb->addr.pgn == J1939_TP_PGN_DAT ||
1931 	    skcb->addr.pgn == J1939_TP_PGN_CTL ||
1932 	    skcb->addr.pgn == J1939_ETP_PGN_DAT ||
1933 	    skcb->addr.pgn == J1939_ETP_PGN_CTL)
1934 		/* avoid conflict */
1935 		return ERR_PTR(-EDOM);
1936 
1937 	if (size > priv->tp_max_packet_size)
1938 		return ERR_PTR(-EMSGSIZE);
1939 
1940 	if (size <= 8)
1941 		skcb->addr.type = J1939_SIMPLE;
1942 	else if (size > J1939_MAX_TP_PACKET_SIZE)
1943 		skcb->addr.type = J1939_ETP;
1944 	else
1945 		skcb->addr.type = J1939_TP;
1946 
1947 	if (skcb->addr.type == J1939_ETP &&
1948 	    j1939_cb_is_broadcast(skcb))
1949 		return ERR_PTR(-EDESTADDRREQ);
1950 
1951 	/* fill in addresses from names */
1952 	ret = j1939_ac_fixup(priv, skb);
1953 	if (unlikely(ret))
1954 		return ERR_PTR(ret);
1955 
1956 	/* fix DST flags, it may be used there soon */
1957 	if (j1939_address_is_unicast(skcb->addr.da) &&
1958 	    priv->ents[skcb->addr.da].nusers)
1959 		skcb->flags |= J1939_ECU_LOCAL_DST;
1960 
1961 	/* src is always local, I'm sending ... */
1962 	skcb->flags |= J1939_ECU_LOCAL_SRC;
1963 
1964 	/* prepare new session */
1965 	session = j1939_session_new(priv, skb, size);
1966 	if (!session)
1967 		return ERR_PTR(-ENOMEM);
1968 
1969 	/* skb is recounted in j1939_session_new() */
1970 	sock_hold(skb->sk);
1971 	session->sk = skb->sk;
1972 	session->transmission = true;
1973 	session->pkt.total = (size + 6) / 7;
1974 	session->pkt.block = skcb->addr.type == J1939_ETP ? 255 :
1975 		min(j1939_tp_block ?: 255, session->pkt.total);
1976 
1977 	if (j1939_cb_is_broadcast(&session->skcb))
1978 		/* set the end-packet for broadcast */
1979 		session->pkt.last = session->pkt.total;
1980 
1981 	skcb->tskey = session->sk->sk_tskey++;
1982 	session->tskey = skcb->tskey;
1983 
1984 	return session;
1985 }
1986 
1987 static void j1939_tp_cmd_recv(struct j1939_priv *priv, struct sk_buff *skb)
1988 {
1989 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
1990 	int extd = J1939_TP;
1991 	u8 cmd = skb->data[0];
1992 
1993 	switch (cmd) {
1994 	case J1939_ETP_CMD_RTS:
1995 		extd = J1939_ETP;
1996 		fallthrough;
1997 	case J1939_TP_CMD_BAM:
1998 	case J1939_TP_CMD_RTS: /* fall through */
1999 		if (skcb->addr.type != extd)
2000 			return;
2001 
2002 		if (cmd == J1939_TP_CMD_RTS && j1939_cb_is_broadcast(skcb)) {
2003 			netdev_alert(priv->ndev, "%s: rts without destination (%02x)\n",
2004 				     __func__, skcb->addr.sa);
2005 			return;
2006 		}
2007 
2008 		if (j1939_tp_im_transmitter(skcb))
2009 			j1939_xtp_rx_rts(priv, skb, true);
2010 
2011 		if (j1939_tp_im_receiver(skcb) || j1939_cb_is_broadcast(skcb))
2012 			j1939_xtp_rx_rts(priv, skb, false);
2013 
2014 		break;
2015 
2016 	case J1939_ETP_CMD_CTS:
2017 		extd = J1939_ETP;
2018 		fallthrough;
2019 	case J1939_TP_CMD_CTS:
2020 		if (skcb->addr.type != extd)
2021 			return;
2022 
2023 		if (j1939_tp_im_transmitter(skcb))
2024 			j1939_xtp_rx_cts(priv, skb, false);
2025 
2026 		if (j1939_tp_im_receiver(skcb))
2027 			j1939_xtp_rx_cts(priv, skb, true);
2028 
2029 		break;
2030 
2031 	case J1939_ETP_CMD_DPO:
2032 		if (skcb->addr.type != J1939_ETP)
2033 			return;
2034 
2035 		if (j1939_tp_im_transmitter(skcb))
2036 			j1939_xtp_rx_dpo(priv, skb, true);
2037 
2038 		if (j1939_tp_im_receiver(skcb))
2039 			j1939_xtp_rx_dpo(priv, skb, false);
2040 
2041 		break;
2042 
2043 	case J1939_ETP_CMD_EOMA:
2044 		extd = J1939_ETP;
2045 		fallthrough;
2046 	case J1939_TP_CMD_EOMA:
2047 		if (skcb->addr.type != extd)
2048 			return;
2049 
2050 		if (j1939_tp_im_transmitter(skcb))
2051 			j1939_xtp_rx_eoma(priv, skb, false);
2052 
2053 		if (j1939_tp_im_receiver(skcb))
2054 			j1939_xtp_rx_eoma(priv, skb, true);
2055 
2056 		break;
2057 
2058 	case J1939_ETP_CMD_ABORT: /* && J1939_TP_CMD_ABORT */
2059 		if (j1939_tp_im_transmitter(skcb))
2060 			j1939_xtp_rx_abort(priv, skb, true);
2061 
2062 		if (j1939_tp_im_receiver(skcb))
2063 			j1939_xtp_rx_abort(priv, skb, false);
2064 
2065 		break;
2066 	default:
2067 		return;
2068 	}
2069 }
2070 
2071 int j1939_tp_recv(struct j1939_priv *priv, struct sk_buff *skb)
2072 {
2073 	struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
2074 
2075 	if (!j1939_tp_im_involved_anydir(skcb) && !j1939_cb_is_broadcast(skcb))
2076 		return 0;
2077 
2078 	switch (skcb->addr.pgn) {
2079 	case J1939_ETP_PGN_DAT:
2080 		skcb->addr.type = J1939_ETP;
2081 		fallthrough;
2082 	case J1939_TP_PGN_DAT:
2083 		j1939_xtp_rx_dat(priv, skb);
2084 		break;
2085 
2086 	case J1939_ETP_PGN_CTL:
2087 		skcb->addr.type = J1939_ETP;
2088 		fallthrough;
2089 	case J1939_TP_PGN_CTL:
2090 		if (skb->len < 8)
2091 			return 0; /* Don't care. Nothing to extract here */
2092 
2093 		j1939_tp_cmd_recv(priv, skb);
2094 		break;
2095 	default:
2096 		return 0; /* no problem */
2097 	}
2098 	return 1; /* "I processed the message" */
2099 }
2100 
2101 void j1939_simple_recv(struct j1939_priv *priv, struct sk_buff *skb)
2102 {
2103 	struct j1939_session *session;
2104 
2105 	if (!skb->sk)
2106 		return;
2107 
2108 	if (skb->sk->sk_family != AF_CAN ||
2109 	    skb->sk->sk_protocol != CAN_J1939)
2110 		return;
2111 
2112 	j1939_session_list_lock(priv);
2113 	session = j1939_session_get_simple(priv, skb);
2114 	j1939_session_list_unlock(priv);
2115 	if (!session) {
2116 		netdev_warn(priv->ndev,
2117 			    "%s: Received already invalidated message\n",
2118 			    __func__);
2119 		return;
2120 	}
2121 
2122 	j1939_session_timers_cancel(session);
2123 	j1939_session_deactivate(session);
2124 	j1939_session_put(session);
2125 }
2126 
2127 int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk)
2128 {
2129 	struct j1939_session *session, *saved;
2130 
2131 	netdev_dbg(priv->ndev, "%s, sk: %p\n", __func__, sk);
2132 	j1939_session_list_lock(priv);
2133 	list_for_each_entry_safe(session, saved,
2134 				 &priv->active_session_list,
2135 				 active_session_list_entry) {
2136 		if (!sk || sk == session->sk) {
2137 			if (hrtimer_try_to_cancel(&session->txtimer) == 1)
2138 				j1939_session_put(session);
2139 			if (hrtimer_try_to_cancel(&session->rxtimer) == 1)
2140 				j1939_session_put(session);
2141 
2142 			session->err = ESHUTDOWN;
2143 			j1939_session_deactivate_locked(session);
2144 		}
2145 	}
2146 	j1939_session_list_unlock(priv);
2147 	return NOTIFY_DONE;
2148 }
2149 
2150 void j1939_tp_init(struct j1939_priv *priv)
2151 {
2152 	spin_lock_init(&priv->active_session_list_lock);
2153 	INIT_LIST_HEAD(&priv->active_session_list);
2154 	priv->tp_max_packet_size = J1939_MAX_ETP_PACKET_SIZE;
2155 }
2156